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Diffstat (limited to 'gcc-4.8/gcc/ada/exp_ch4.adb')
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diff --git a/gcc-4.8/gcc/ada/exp_ch4.adb b/gcc-4.8/gcc/ada/exp_ch4.adb deleted file mode 100644 index f8d37a553..000000000 --- a/gcc-4.8/gcc/ada/exp_ch4.adb +++ /dev/null @@ -1,12806 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT COMPILER COMPONENTS -- --- -- --- E X P _ C H 4 -- --- -- --- B o d y -- --- -- --- Copyright (C) 1992-2013, Free Software Foundation, Inc. -- --- -- --- GNAT is free software; you can redistribute it and/or modify it under -- --- terms of the GNU General Public License as published by the Free Soft- -- --- ware Foundation; either version 3, or (at your option) any later ver- -- --- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- --- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- --- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- --- for more details. You should have received a copy of the GNU General -- --- Public License distributed with GNAT; see file COPYING3. If not, go to -- --- http://www.gnu.org/licenses for a complete copy of the license. -- --- -- --- GNAT was originally developed by the GNAT team at New York University. -- --- Extensive contributions were provided by Ada Core Technologies Inc. -- --- -- ------------------------------------------------------------------------------- - -with Atree; use Atree; -with Checks; use Checks; -with Debug; use Debug; -with Einfo; use Einfo; -with Elists; use Elists; -with Errout; use Errout; -with Exp_Aggr; use Exp_Aggr; -with Exp_Atag; use Exp_Atag; -with Exp_Ch2; use Exp_Ch2; -with Exp_Ch3; use Exp_Ch3; -with Exp_Ch6; use Exp_Ch6; -with Exp_Ch7; use Exp_Ch7; -with Exp_Ch9; use Exp_Ch9; -with Exp_Disp; use Exp_Disp; -with Exp_Fixd; use Exp_Fixd; -with Exp_Intr; use Exp_Intr; -with Exp_Pakd; use Exp_Pakd; -with Exp_Tss; use Exp_Tss; -with Exp_Util; use Exp_Util; -with Exp_VFpt; use Exp_VFpt; -with Freeze; use Freeze; -with Inline; use Inline; -with Lib; use Lib; -with Namet; use Namet; -with Nlists; use Nlists; -with Nmake; use Nmake; -with Opt; use Opt; -with Par_SCO; use Par_SCO; -with Restrict; use Restrict; -with Rident; use Rident; -with Rtsfind; use Rtsfind; -with Sem; use Sem; -with Sem_Aux; use Sem_Aux; -with Sem_Cat; use Sem_Cat; -with Sem_Ch3; use Sem_Ch3; -with Sem_Ch8; use Sem_Ch8; -with Sem_Ch13; use Sem_Ch13; -with Sem_Eval; use Sem_Eval; -with Sem_Res; use Sem_Res; -with Sem_Type; use Sem_Type; -with Sem_Util; use Sem_Util; -with Sem_Warn; use Sem_Warn; -with Sinfo; use Sinfo; -with Snames; use Snames; -with Stand; use Stand; -with SCIL_LL; use SCIL_LL; -with Targparm; use Targparm; -with Tbuild; use Tbuild; -with Ttypes; use Ttypes; -with Uintp; use Uintp; -with Urealp; use Urealp; -with Validsw; use Validsw; - -package body Exp_Ch4 is - - ----------------------- - -- Local Subprograms -- - ----------------------- - - procedure Binary_Op_Validity_Checks (N : Node_Id); - pragma Inline (Binary_Op_Validity_Checks); - -- Performs validity checks for a binary operator - - procedure Build_Boolean_Array_Proc_Call - (N : Node_Id; - Op1 : Node_Id; - Op2 : Node_Id); - -- If a boolean array assignment can be done in place, build call to - -- corresponding library procedure. - - function Current_Anonymous_Master return Entity_Id; - -- Return the entity of the heterogeneous finalization master belonging to - -- the current unit (either function, package or procedure). This master - -- services all anonymous access-to-controlled types. If the current unit - -- does not have such master, create one. - - procedure Displace_Allocator_Pointer (N : Node_Id); - -- Ada 2005 (AI-251): Subsidiary procedure to Expand_N_Allocator and - -- Expand_Allocator_Expression. Allocating class-wide interface objects - -- this routine displaces the pointer to the allocated object to reference - -- the component referencing the corresponding secondary dispatch table. - - procedure Expand_Allocator_Expression (N : Node_Id); - -- Subsidiary to Expand_N_Allocator, for the case when the expression - -- is a qualified expression or an aggregate. - - procedure Expand_Array_Comparison (N : Node_Id); - -- This routine handles expansion of the comparison operators (N_Op_Lt, - -- N_Op_Le, N_Op_Gt, N_Op_Ge) when operating on an array type. The basic - -- code for these operators is similar, differing only in the details of - -- the actual comparison call that is made. Special processing (call a - -- run-time routine) - - function Expand_Array_Equality - (Nod : Node_Id; - Lhs : Node_Id; - Rhs : Node_Id; - Bodies : List_Id; - Typ : Entity_Id) return Node_Id; - -- Expand an array equality into a call to a function implementing this - -- equality, and a call to it. Loc is the location for the generated nodes. - -- Lhs and Rhs are the array expressions to be compared. Bodies is a list - -- on which to attach bodies of local functions that are created in the - -- process. It is the responsibility of the caller to insert those bodies - -- at the right place. Nod provides the Sloc value for the generated code. - -- Normally the types used for the generated equality routine are taken - -- from Lhs and Rhs. However, in some situations of generated code, the - -- Etype fields of Lhs and Rhs are not set yet. In such cases, Typ supplies - -- the type to be used for the formal parameters. - - procedure Expand_Boolean_Operator (N : Node_Id); - -- Common expansion processing for Boolean operators (And, Or, Xor) for the - -- case of array type arguments. - - procedure Expand_Short_Circuit_Operator (N : Node_Id); - -- Common expansion processing for short-circuit boolean operators - - procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id); - -- Deal with comparison in MINIMIZED/ELIMINATED overflow mode. This is - -- where we allow comparison of "out of range" values. - - function Expand_Composite_Equality - (Nod : Node_Id; - Typ : Entity_Id; - Lhs : Node_Id; - Rhs : Node_Id; - Bodies : List_Id) return Node_Id; - -- Local recursive function used to expand equality for nested composite - -- types. Used by Expand_Record/Array_Equality, Bodies is a list on which - -- to attach bodies of local functions that are created in the process. - -- It is the responsibility of the caller to insert those bodies at the - -- right place. Nod provides the Sloc value for generated code. Lhs and Rhs - -- are the left and right sides for the comparison, and Typ is the type of - -- the objects to compare. - - procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id); - -- Routine to expand concatenation of a sequence of two or more operands - -- (in the list Operands) and replace node Cnode with the result of the - -- concatenation. The operands can be of any appropriate type, and can - -- include both arrays and singleton elements. - - procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id); - -- N is an N_In membership test mode, with the overflow check mode set to - -- MINIMIZED or ELIMINATED, and the type of the left operand is a signed - -- integer type. This is a case where top level processing is required to - -- handle overflow checks in subtrees. - - procedure Fixup_Universal_Fixed_Operation (N : Node_Id); - -- N is a N_Op_Divide or N_Op_Multiply node whose result is universal - -- fixed. We do not have such a type at runtime, so the purpose of this - -- routine is to find the real type by looking up the tree. We also - -- determine if the operation must be rounded. - - function Has_Inferable_Discriminants (N : Node_Id) return Boolean; - -- Ada 2005 (AI-216): A view of an Unchecked_Union object has inferable - -- discriminants if it has a constrained nominal type, unless the object - -- is a component of an enclosing Unchecked_Union object that is subject - -- to a per-object constraint and the enclosing object lacks inferable - -- discriminants. - -- - -- An expression of an Unchecked_Union type has inferable discriminants - -- if it is either a name of an object with inferable discriminants or a - -- qualified expression whose subtype mark denotes a constrained subtype. - - procedure Insert_Dereference_Action (N : Node_Id); - -- N is an expression whose type is an access. When the type of the - -- associated storage pool is derived from Checked_Pool, generate a - -- call to the 'Dereference' primitive operation. - - function Make_Array_Comparison_Op - (Typ : Entity_Id; - Nod : Node_Id) return Node_Id; - -- Comparisons between arrays are expanded in line. This function produces - -- the body of the implementation of (a > b), where a and b are one- - -- dimensional arrays of some discrete type. The original node is then - -- expanded into the appropriate call to this function. Nod provides the - -- Sloc value for the generated code. - - function Make_Boolean_Array_Op - (Typ : Entity_Id; - N : Node_Id) return Node_Id; - -- Boolean operations on boolean arrays are expanded in line. This function - -- produce the body for the node N, which is (a and b), (a or b), or (a xor - -- b). It is used only the normal case and not the packed case. The type - -- involved, Typ, is the Boolean array type, and the logical operations in - -- the body are simple boolean operations. Note that Typ is always a - -- constrained type (the caller has ensured this by using - -- Convert_To_Actual_Subtype if necessary). - - function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean; - -- For signed arithmetic operations when the current overflow mode is - -- MINIMIZED or ELIMINATED, we must call Apply_Arithmetic_Overflow_Checks - -- as the first thing we do. We then return. We count on the recursive - -- apparatus for overflow checks to call us back with an equivalent - -- operation that is in CHECKED mode, avoiding a recursive entry into this - -- routine, and that is when we will proceed with the expansion of the - -- operator (e.g. converting X+0 to X, or X**2 to X*X). We cannot do - -- these optimizations without first making this check, since there may be - -- operands further down the tree that are relying on the recursive calls - -- triggered by the top level nodes to properly process overflow checking - -- and remaining expansion on these nodes. Note that this call back may be - -- skipped if the operation is done in Bignum mode but that's fine, since - -- the Bignum call takes care of everything. - - procedure Optimize_Length_Comparison (N : Node_Id); - -- Given an expression, if it is of the form X'Length op N (or the other - -- way round), where N is known at compile time to be 0 or 1, and X is a - -- simple entity, and op is a comparison operator, optimizes it into a - -- comparison of First and Last. - - procedure Rewrite_Comparison (N : Node_Id); - -- If N is the node for a comparison whose outcome can be determined at - -- compile time, then the node N can be rewritten with True or False. If - -- the outcome cannot be determined at compile time, the call has no - -- effect. If N is a type conversion, then this processing is applied to - -- its expression. If N is neither comparison nor a type conversion, the - -- call has no effect. - - procedure Tagged_Membership - (N : Node_Id; - SCIL_Node : out Node_Id; - Result : out Node_Id); - -- Construct the expression corresponding to the tagged membership test. - -- Deals with a second operand being (or not) a class-wide type. - - function Safe_In_Place_Array_Op - (Lhs : Node_Id; - Op1 : Node_Id; - Op2 : Node_Id) return Boolean; - -- In the context of an assignment, where the right-hand side is a boolean - -- operation on arrays, check whether operation can be performed in place. - - procedure Unary_Op_Validity_Checks (N : Node_Id); - pragma Inline (Unary_Op_Validity_Checks); - -- Performs validity checks for a unary operator - - ------------------------------- - -- Binary_Op_Validity_Checks -- - ------------------------------- - - procedure Binary_Op_Validity_Checks (N : Node_Id) is - begin - if Validity_Checks_On and Validity_Check_Operands then - Ensure_Valid (Left_Opnd (N)); - Ensure_Valid (Right_Opnd (N)); - end if; - end Binary_Op_Validity_Checks; - - ------------------------------------ - -- Build_Boolean_Array_Proc_Call -- - ------------------------------------ - - procedure Build_Boolean_Array_Proc_Call - (N : Node_Id; - Op1 : Node_Id; - Op2 : Node_Id) - is - Loc : constant Source_Ptr := Sloc (N); - Kind : constant Node_Kind := Nkind (Expression (N)); - Target : constant Node_Id := - Make_Attribute_Reference (Loc, - Prefix => Name (N), - Attribute_Name => Name_Address); - - Arg1 : Node_Id := Op1; - Arg2 : Node_Id := Op2; - Call_Node : Node_Id; - Proc_Name : Entity_Id; - - begin - if Kind = N_Op_Not then - if Nkind (Op1) in N_Binary_Op then - - -- Use negated version of the binary operators - - if Nkind (Op1) = N_Op_And then - Proc_Name := RTE (RE_Vector_Nand); - - elsif Nkind (Op1) = N_Op_Or then - Proc_Name := RTE (RE_Vector_Nor); - - else pragma Assert (Nkind (Op1) = N_Op_Xor); - Proc_Name := RTE (RE_Vector_Xor); - end if; - - Call_Node := - Make_Procedure_Call_Statement (Loc, - Name => New_Occurrence_Of (Proc_Name, Loc), - - Parameter_Associations => New_List ( - Target, - Make_Attribute_Reference (Loc, - Prefix => Left_Opnd (Op1), - Attribute_Name => Name_Address), - - Make_Attribute_Reference (Loc, - Prefix => Right_Opnd (Op1), - Attribute_Name => Name_Address), - - Make_Attribute_Reference (Loc, - Prefix => Left_Opnd (Op1), - Attribute_Name => Name_Length))); - - else - Proc_Name := RTE (RE_Vector_Not); - - Call_Node := - Make_Procedure_Call_Statement (Loc, - Name => New_Occurrence_Of (Proc_Name, Loc), - Parameter_Associations => New_List ( - Target, - - Make_Attribute_Reference (Loc, - Prefix => Op1, - Attribute_Name => Name_Address), - - Make_Attribute_Reference (Loc, - Prefix => Op1, - Attribute_Name => Name_Length))); - end if; - - else - -- We use the following equivalences: - - -- (not X) or (not Y) = not (X and Y) = Nand (X, Y) - -- (not X) and (not Y) = not (X or Y) = Nor (X, Y) - -- (not X) xor (not Y) = X xor Y - -- X xor (not Y) = not (X xor Y) = Nxor (X, Y) - - if Nkind (Op1) = N_Op_Not then - Arg1 := Right_Opnd (Op1); - Arg2 := Right_Opnd (Op2); - if Kind = N_Op_And then - Proc_Name := RTE (RE_Vector_Nor); - elsif Kind = N_Op_Or then - Proc_Name := RTE (RE_Vector_Nand); - else - Proc_Name := RTE (RE_Vector_Xor); - end if; - - else - if Kind = N_Op_And then - Proc_Name := RTE (RE_Vector_And); - elsif Kind = N_Op_Or then - Proc_Name := RTE (RE_Vector_Or); - elsif Nkind (Op2) = N_Op_Not then - Proc_Name := RTE (RE_Vector_Nxor); - Arg2 := Right_Opnd (Op2); - else - Proc_Name := RTE (RE_Vector_Xor); - end if; - end if; - - Call_Node := - Make_Procedure_Call_Statement (Loc, - Name => New_Occurrence_Of (Proc_Name, Loc), - Parameter_Associations => New_List ( - Target, - Make_Attribute_Reference (Loc, - Prefix => Arg1, - Attribute_Name => Name_Address), - Make_Attribute_Reference (Loc, - Prefix => Arg2, - Attribute_Name => Name_Address), - Make_Attribute_Reference (Loc, - Prefix => Arg1, - Attribute_Name => Name_Length))); - end if; - - Rewrite (N, Call_Node); - Analyze (N); - - exception - when RE_Not_Available => - return; - end Build_Boolean_Array_Proc_Call; - - ------------------------------ - -- Current_Anonymous_Master -- - ------------------------------ - - function Current_Anonymous_Master return Entity_Id is - Decls : List_Id; - Loc : Source_Ptr; - Subp_Body : Node_Id; - Unit_Decl : Node_Id; - Unit_Id : Entity_Id; - - begin - Unit_Id := Cunit_Entity (Current_Sem_Unit); - - -- Find the entity of the current unit - - if Ekind (Unit_Id) = E_Subprogram_Body then - - -- When processing subprogram bodies, the proper scope is always that - -- of the spec. - - Subp_Body := Unit_Id; - while Present (Subp_Body) - and then Nkind (Subp_Body) /= N_Subprogram_Body - loop - Subp_Body := Parent (Subp_Body); - end loop; - - Unit_Id := Corresponding_Spec (Subp_Body); - end if; - - Loc := Sloc (Unit_Id); - Unit_Decl := Unit (Cunit (Current_Sem_Unit)); - - -- Find the declarations list of the current unit - - if Nkind (Unit_Decl) = N_Package_Declaration then - Unit_Decl := Specification (Unit_Decl); - Decls := Visible_Declarations (Unit_Decl); - - if No (Decls) then - Decls := New_List (Make_Null_Statement (Loc)); - Set_Visible_Declarations (Unit_Decl, Decls); - - elsif Is_Empty_List (Decls) then - Append_To (Decls, Make_Null_Statement (Loc)); - end if; - - else - Decls := Declarations (Unit_Decl); - - if No (Decls) then - Decls := New_List (Make_Null_Statement (Loc)); - Set_Declarations (Unit_Decl, Decls); - - elsif Is_Empty_List (Decls) then - Append_To (Decls, Make_Null_Statement (Loc)); - end if; - end if; - - -- The current unit has an existing anonymous master, traverse its - -- declarations and locate the entity. - - if Has_Anonymous_Master (Unit_Id) then - declare - Decl : Node_Id; - Fin_Mas_Id : Entity_Id; - - begin - Decl := First (Decls); - while Present (Decl) loop - - -- Look for the first variable in the declarations whole type - -- is Finalization_Master. - - if Nkind (Decl) = N_Object_Declaration then - Fin_Mas_Id := Defining_Identifier (Decl); - - if Ekind (Fin_Mas_Id) = E_Variable - and then Etype (Fin_Mas_Id) = RTE (RE_Finalization_Master) - then - return Fin_Mas_Id; - end if; - end if; - - Next (Decl); - end loop; - - -- The master was not found even though the unit was labeled as - -- having one. - - raise Program_Error; - end; - - -- Create a new anonymous master - - else - declare - First_Decl : constant Node_Id := First (Decls); - Action : Node_Id; - Fin_Mas_Id : Entity_Id; - - begin - -- Since the master and its associated initialization is inserted - -- at top level, use the scope of the unit when analyzing. - - Push_Scope (Unit_Id); - - -- Create the finalization master - - Fin_Mas_Id := - Make_Defining_Identifier (Loc, - Chars => New_External_Name (Chars (Unit_Id), "AM")); - - -- Generate: - -- <Fin_Mas_Id> : Finalization_Master; - - Action := - Make_Object_Declaration (Loc, - Defining_Identifier => Fin_Mas_Id, - Object_Definition => - New_Reference_To (RTE (RE_Finalization_Master), Loc)); - - Insert_Before_And_Analyze (First_Decl, Action); - - -- Mark the unit to prevent the generation of multiple masters - - Set_Has_Anonymous_Master (Unit_Id); - - -- Do not set the base pool and mode of operation on .NET/JVM - -- since those targets do not support pools and all VM masters - -- are heterogeneous by default. - - if VM_Target = No_VM then - - -- Generate: - -- Set_Base_Pool - -- (<Fin_Mas_Id>, Global_Pool_Object'Unrestricted_Access); - - Action := - Make_Procedure_Call_Statement (Loc, - Name => - New_Reference_To (RTE (RE_Set_Base_Pool), Loc), - - Parameter_Associations => New_List ( - New_Reference_To (Fin_Mas_Id, Loc), - Make_Attribute_Reference (Loc, - Prefix => - New_Reference_To (RTE (RE_Global_Pool_Object), Loc), - Attribute_Name => Name_Unrestricted_Access))); - - Insert_Before_And_Analyze (First_Decl, Action); - - -- Generate: - -- Set_Is_Heterogeneous (<Fin_Mas_Id>); - - Action := - Make_Procedure_Call_Statement (Loc, - Name => - New_Reference_To (RTE (RE_Set_Is_Heterogeneous), Loc), - Parameter_Associations => New_List ( - New_Reference_To (Fin_Mas_Id, Loc))); - - Insert_Before_And_Analyze (First_Decl, Action); - end if; - - -- Restore the original state of the scope stack - - Pop_Scope; - - return Fin_Mas_Id; - end; - end if; - end Current_Anonymous_Master; - - -------------------------------- - -- Displace_Allocator_Pointer -- - -------------------------------- - - procedure Displace_Allocator_Pointer (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Orig_Node : constant Node_Id := Original_Node (N); - Dtyp : Entity_Id; - Etyp : Entity_Id; - PtrT : Entity_Id; - - begin - -- Do nothing in case of VM targets: the virtual machine will handle - -- interfaces directly. - - if not Tagged_Type_Expansion then - return; - end if; - - pragma Assert (Nkind (N) = N_Identifier - and then Nkind (Orig_Node) = N_Allocator); - - PtrT := Etype (Orig_Node); - Dtyp := Available_View (Designated_Type (PtrT)); - Etyp := Etype (Expression (Orig_Node)); - - if Is_Class_Wide_Type (Dtyp) - and then Is_Interface (Dtyp) - then - -- If the type of the allocator expression is not an interface type - -- we can generate code to reference the record component containing - -- the pointer to the secondary dispatch table. - - if not Is_Interface (Etyp) then - declare - Saved_Typ : constant Entity_Id := Etype (Orig_Node); - - begin - -- 1) Get access to the allocated object - - Rewrite (N, - Make_Explicit_Dereference (Loc, Relocate_Node (N))); - Set_Etype (N, Etyp); - Set_Analyzed (N); - - -- 2) Add the conversion to displace the pointer to reference - -- the secondary dispatch table. - - Rewrite (N, Convert_To (Dtyp, Relocate_Node (N))); - Analyze_And_Resolve (N, Dtyp); - - -- 3) The 'access to the secondary dispatch table will be used - -- as the value returned by the allocator. - - Rewrite (N, - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (N), - Attribute_Name => Name_Access)); - Set_Etype (N, Saved_Typ); - Set_Analyzed (N); - end; - - -- If the type of the allocator expression is an interface type we - -- generate a run-time call to displace "this" to reference the - -- component containing the pointer to the secondary dispatch table - -- or else raise Constraint_Error if the actual object does not - -- implement the target interface. This case corresponds with the - -- following example: - - -- function Op (Obj : Iface_1'Class) return access Iface_2'Class is - -- begin - -- return new Iface_2'Class'(Obj); - -- end Op; - - else - Rewrite (N, - Unchecked_Convert_To (PtrT, - Make_Function_Call (Loc, - Name => New_Reference_To (RTE (RE_Displace), Loc), - Parameter_Associations => New_List ( - Unchecked_Convert_To (RTE (RE_Address), - Relocate_Node (N)), - - New_Occurrence_Of - (Elists.Node - (First_Elmt - (Access_Disp_Table (Etype (Base_Type (Dtyp))))), - Loc))))); - Analyze_And_Resolve (N, PtrT); - end if; - end if; - end Displace_Allocator_Pointer; - - --------------------------------- - -- Expand_Allocator_Expression -- - --------------------------------- - - procedure Expand_Allocator_Expression (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Exp : constant Node_Id := Expression (Expression (N)); - PtrT : constant Entity_Id := Etype (N); - DesigT : constant Entity_Id := Designated_Type (PtrT); - - procedure Apply_Accessibility_Check - (Ref : Node_Id; - Built_In_Place : Boolean := False); - -- Ada 2005 (AI-344): For an allocator with a class-wide designated - -- type, generate an accessibility check to verify that the level of the - -- type of the created object is not deeper than the level of the access - -- type. If the type of the qualified expression is class-wide, then - -- always generate the check (except in the case where it is known to be - -- unnecessary, see comment below). Otherwise, only generate the check - -- if the level of the qualified expression type is statically deeper - -- than the access type. - -- - -- Although the static accessibility will generally have been performed - -- as a legality check, it won't have been done in cases where the - -- allocator appears in generic body, so a run-time check is needed in - -- general. One special case is when the access type is declared in the - -- same scope as the class-wide allocator, in which case the check can - -- never fail, so it need not be generated. - -- - -- As an open issue, there seem to be cases where the static level - -- associated with the class-wide object's underlying type is not - -- sufficient to perform the proper accessibility check, such as for - -- allocators in nested subprograms or accept statements initialized by - -- class-wide formals when the actual originates outside at a deeper - -- static level. The nested subprogram case might require passing - -- accessibility levels along with class-wide parameters, and the task - -- case seems to be an actual gap in the language rules that needs to - -- be fixed by the ARG. ??? - - ------------------------------- - -- Apply_Accessibility_Check -- - ------------------------------- - - procedure Apply_Accessibility_Check - (Ref : Node_Id; - Built_In_Place : Boolean := False) - is - Pool_Id : constant Entity_Id := Associated_Storage_Pool (PtrT); - Cond : Node_Id; - Free_Stmt : Node_Id; - Obj_Ref : Node_Id; - Stmts : List_Id; - - begin - if Ada_Version >= Ada_2005 - and then Is_Class_Wide_Type (DesigT) - and then not Scope_Suppress.Suppress (Accessibility_Check) - and then - (Type_Access_Level (Etype (Exp)) > Type_Access_Level (PtrT) - or else - (Is_Class_Wide_Type (Etype (Exp)) - and then Scope (PtrT) /= Current_Scope)) - and then (Tagged_Type_Expansion or else VM_Target /= No_VM) - then - -- If the allocator was built in place, Ref is already a reference - -- to the access object initialized to the result of the allocator - -- (see Exp_Ch6.Make_Build_In_Place_Call_In_Allocator). We call - -- Remove_Side_Effects for cases where the build-in-place call may - -- still be the prefix of the reference (to avoid generating - -- duplicate calls). Otherwise, it is the entity associated with - -- the object containing the address of the allocated object. - - if Built_In_Place then - Remove_Side_Effects (Ref); - Obj_Ref := New_Copy (Ref); - else - Obj_Ref := New_Reference_To (Ref, Loc); - end if; - - -- Step 1: Create the object clean up code - - Stmts := New_List; - - -- Create an explicit free statement to clean up the allocated - -- object in case the accessibility check fails. Generate: - - -- Free (Obj_Ref); - - Free_Stmt := Make_Free_Statement (Loc, New_Copy (Obj_Ref)); - Set_Storage_Pool (Free_Stmt, Pool_Id); - - Append_To (Stmts, Free_Stmt); - - -- Finalize the object (if applicable), but wrap the call inside - -- a block to ensure that the object would still be deallocated in - -- case the finalization fails. Generate: - - -- begin - -- [Deep_]Finalize (Obj_Ref.all); - -- exception - -- when others => - -- Free (Obj_Ref); - -- raise; - -- end; - - if Needs_Finalization (DesigT) then - Prepend_To (Stmts, - Make_Block_Statement (Loc, - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List ( - Make_Final_Call ( - Obj_Ref => - Make_Explicit_Dereference (Loc, - Prefix => New_Copy (Obj_Ref)), - Typ => DesigT)), - - Exception_Handlers => New_List ( - Make_Exception_Handler (Loc, - Exception_Choices => New_List ( - Make_Others_Choice (Loc)), - Statements => New_List ( - New_Copy_Tree (Free_Stmt), - Make_Raise_Statement (Loc))))))); - end if; - - -- Signal the accessibility failure through a Program_Error - - Append_To (Stmts, - Make_Raise_Program_Error (Loc, - Condition => New_Reference_To (Standard_True, Loc), - Reason => PE_Accessibility_Check_Failed)); - - -- Step 2: Create the accessibility comparison - - -- Generate: - -- Ref'Tag - - Obj_Ref := - Make_Attribute_Reference (Loc, - Prefix => Obj_Ref, - Attribute_Name => Name_Tag); - - -- For tagged types, determine the accessibility level by looking - -- at the type specific data of the dispatch table. Generate: - - -- Type_Specific_Data (Address (Ref'Tag)).Access_Level - - if Tagged_Type_Expansion then - Cond := Build_Get_Access_Level (Loc, Obj_Ref); - - -- Use a runtime call to determine the accessibility level when - -- compiling on virtual machine targets. Generate: - - -- Get_Access_Level (Ref'Tag) - - else - Cond := - Make_Function_Call (Loc, - Name => - New_Reference_To (RTE (RE_Get_Access_Level), Loc), - Parameter_Associations => New_List (Obj_Ref)); - end if; - - Cond := - Make_Op_Gt (Loc, - Left_Opnd => Cond, - Right_Opnd => - Make_Integer_Literal (Loc, Type_Access_Level (PtrT))); - - -- Due to the complexity and side effects of the check, utilize an - -- if statement instead of the regular Program_Error circuitry. - - Insert_Action (N, - Make_If_Statement (Loc, - Condition => Cond, - Then_Statements => Stmts)); - end if; - end Apply_Accessibility_Check; - - -- Local variables - - Aggr_In_Place : constant Boolean := Is_Delayed_Aggregate (Exp); - Indic : constant Node_Id := Subtype_Mark (Expression (N)); - T : constant Entity_Id := Entity (Indic); - Node : Node_Id; - Tag_Assign : Node_Id; - Temp : Entity_Id; - Temp_Decl : Node_Id; - - TagT : Entity_Id := Empty; - -- Type used as source for tag assignment - - TagR : Node_Id := Empty; - -- Target reference for tag assignment - - -- Start of processing for Expand_Allocator_Expression - - begin - -- Handle call to C++ constructor - - if Is_CPP_Constructor_Call (Exp) then - Make_CPP_Constructor_Call_In_Allocator - (Allocator => N, - Function_Call => Exp); - return; - end if; - - -- In the case of an Ada 2012 allocator whose initial value comes from a - -- function call, pass "the accessibility level determined by the point - -- of call" (AI05-0234) to the function. Conceptually, this belongs in - -- Expand_Call but it couldn't be done there (because the Etype of the - -- allocator wasn't set then) so we generate the parameter here. See - -- the Boolean variable Defer in (a block within) Expand_Call. - - if Ada_Version >= Ada_2012 and then Nkind (Exp) = N_Function_Call then - declare - Subp : Entity_Id; - - begin - if Nkind (Name (Exp)) = N_Explicit_Dereference then - Subp := Designated_Type (Etype (Prefix (Name (Exp)))); - else - Subp := Entity (Name (Exp)); - end if; - - Subp := Ultimate_Alias (Subp); - - if Present (Extra_Accessibility_Of_Result (Subp)) then - Add_Extra_Actual_To_Call - (Subprogram_Call => Exp, - Extra_Formal => Extra_Accessibility_Of_Result (Subp), - Extra_Actual => Dynamic_Accessibility_Level (PtrT)); - end if; - end; - end if; - - -- Case of tagged type or type requiring finalization - - if Is_Tagged_Type (T) or else Needs_Finalization (T) then - - -- Ada 2005 (AI-318-02): If the initialization expression is a call - -- to a build-in-place function, then access to the allocated object - -- must be passed to the function. Currently we limit such functions - -- to those with constrained limited result subtypes, but eventually - -- we plan to expand the allowed forms of functions that are treated - -- as build-in-place. - - if Ada_Version >= Ada_2005 - and then Is_Build_In_Place_Function_Call (Exp) - then - Make_Build_In_Place_Call_In_Allocator (N, Exp); - Apply_Accessibility_Check (N, Built_In_Place => True); - return; - end if; - - -- Actions inserted before: - -- Temp : constant ptr_T := new T'(Expression); - -- Temp._tag = T'tag; -- when not class-wide - -- [Deep_]Adjust (Temp.all); - - -- We analyze by hand the new internal allocator to avoid any - -- recursion and inappropriate call to Initialize - - -- We don't want to remove side effects when the expression must be - -- built in place. In the case of a build-in-place function call, - -- that could lead to a duplication of the call, which was already - -- substituted for the allocator. - - if not Aggr_In_Place then - Remove_Side_Effects (Exp); - end if; - - Temp := Make_Temporary (Loc, 'P', N); - - -- For a class wide allocation generate the following code: - - -- type Equiv_Record is record ... end record; - -- implicit subtype CW is <Class_Wide_Subytpe>; - -- temp : PtrT := new CW'(CW!(expr)); - - if Is_Class_Wide_Type (T) then - Expand_Subtype_From_Expr (Empty, T, Indic, Exp); - - -- Ada 2005 (AI-251): If the expression is a class-wide interface - -- object we generate code to move up "this" to reference the - -- base of the object before allocating the new object. - - -- Note that Exp'Address is recursively expanded into a call - -- to Base_Address (Exp.Tag) - - if Is_Class_Wide_Type (Etype (Exp)) - and then Is_Interface (Etype (Exp)) - and then Tagged_Type_Expansion - then - Set_Expression - (Expression (N), - Unchecked_Convert_To (Entity (Indic), - Make_Explicit_Dereference (Loc, - Unchecked_Convert_To (RTE (RE_Tag_Ptr), - Make_Attribute_Reference (Loc, - Prefix => Exp, - Attribute_Name => Name_Address))))); - else - Set_Expression - (Expression (N), - Unchecked_Convert_To (Entity (Indic), Exp)); - end if; - - Analyze_And_Resolve (Expression (N), Entity (Indic)); - end if; - - -- Processing for allocators returning non-interface types - - if not Is_Interface (Directly_Designated_Type (PtrT)) then - if Aggr_In_Place then - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Object_Definition => New_Reference_To (PtrT, Loc), - Expression => - Make_Allocator (Loc, - Expression => - New_Reference_To (Etype (Exp), Loc))); - - -- Copy the Comes_From_Source flag for the allocator we just - -- built, since logically this allocator is a replacement of - -- the original allocator node. This is for proper handling of - -- restriction No_Implicit_Heap_Allocations. - - Set_Comes_From_Source - (Expression (Temp_Decl), Comes_From_Source (N)); - - Set_No_Initialization (Expression (Temp_Decl)); - Insert_Action (N, Temp_Decl); - - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); - - -- Attach the object to the associated finalization master. - -- This is done manually on .NET/JVM since those compilers do - -- no support pools and can't benefit from internally generated - -- Allocate / Deallocate procedures. - - if VM_Target /= No_VM - and then Is_Controlled (DesigT) - and then Present (Finalization_Master (PtrT)) - then - Insert_Action (N, - Make_Attach_Call ( - Obj_Ref => - New_Reference_To (Temp, Loc), - Ptr_Typ => PtrT)); - end if; - - else - Node := Relocate_Node (N); - Set_Analyzed (Node); - - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Constant_Present => True, - Object_Definition => New_Reference_To (PtrT, Loc), - Expression => Node); - - Insert_Action (N, Temp_Decl); - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - - -- Attach the object to the associated finalization master. - -- This is done manually on .NET/JVM since those compilers do - -- no support pools and can't benefit from internally generated - -- Allocate / Deallocate procedures. - - if VM_Target /= No_VM - and then Is_Controlled (DesigT) - and then Present (Finalization_Master (PtrT)) - then - Insert_Action (N, - Make_Attach_Call ( - Obj_Ref => - New_Reference_To (Temp, Loc), - Ptr_Typ => PtrT)); - end if; - end if; - - -- Ada 2005 (AI-251): Handle allocators whose designated type is an - -- interface type. In this case we use the type of the qualified - -- expression to allocate the object. - - else - declare - Def_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); - New_Decl : Node_Id; - - begin - New_Decl := - Make_Full_Type_Declaration (Loc, - Defining_Identifier => Def_Id, - Type_Definition => - Make_Access_To_Object_Definition (Loc, - All_Present => True, - Null_Exclusion_Present => False, - Constant_Present => - Is_Access_Constant (Etype (N)), - Subtype_Indication => - New_Reference_To (Etype (Exp), Loc))); - - Insert_Action (N, New_Decl); - - -- Inherit the allocation-related attributes from the original - -- access type. - - Set_Finalization_Master (Def_Id, Finalization_Master (PtrT)); - - Set_Associated_Storage_Pool (Def_Id, - Associated_Storage_Pool (PtrT)); - - -- Declare the object using the previous type declaration - - if Aggr_In_Place then - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Object_Definition => New_Reference_To (Def_Id, Loc), - Expression => - Make_Allocator (Loc, - New_Reference_To (Etype (Exp), Loc))); - - -- Copy the Comes_From_Source flag for the allocator we just - -- built, since logically this allocator is a replacement of - -- the original allocator node. This is for proper handling - -- of restriction No_Implicit_Heap_Allocations. - - Set_Comes_From_Source - (Expression (Temp_Decl), Comes_From_Source (N)); - - Set_No_Initialization (Expression (Temp_Decl)); - Insert_Action (N, Temp_Decl); - - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); - - else - Node := Relocate_Node (N); - Set_Analyzed (Node); - - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Constant_Present => True, - Object_Definition => New_Reference_To (Def_Id, Loc), - Expression => Node); - - Insert_Action (N, Temp_Decl); - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - end if; - - -- Generate an additional object containing the address of the - -- returned object. The type of this second object declaration - -- is the correct type required for the common processing that - -- is still performed by this subprogram. The displacement of - -- this pointer to reference the component associated with the - -- interface type will be done at the end of common processing. - - New_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Make_Temporary (Loc, 'P'), - Object_Definition => New_Reference_To (PtrT, Loc), - Expression => - Unchecked_Convert_To (PtrT, - New_Reference_To (Temp, Loc))); - - Insert_Action (N, New_Decl); - - Temp_Decl := New_Decl; - Temp := Defining_Identifier (New_Decl); - end; - end if; - - Apply_Accessibility_Check (Temp); - - -- Generate the tag assignment - - -- Suppress the tag assignment when VM_Target because VM tags are - -- represented implicitly in objects. - - if not Tagged_Type_Expansion then - null; - - -- Ada 2005 (AI-251): Suppress the tag assignment with class-wide - -- interface objects because in this case the tag does not change. - - elsif Is_Interface (Directly_Designated_Type (Etype (N))) then - pragma Assert (Is_Class_Wide_Type - (Directly_Designated_Type (Etype (N)))); - null; - - elsif Is_Tagged_Type (T) and then not Is_Class_Wide_Type (T) then - TagT := T; - TagR := New_Reference_To (Temp, Loc); - - elsif Is_Private_Type (T) - and then Is_Tagged_Type (Underlying_Type (T)) - then - TagT := Underlying_Type (T); - TagR := - Unchecked_Convert_To (Underlying_Type (T), - Make_Explicit_Dereference (Loc, - Prefix => New_Reference_To (Temp, Loc))); - end if; - - if Present (TagT) then - declare - Full_T : constant Entity_Id := Underlying_Type (TagT); - begin - Tag_Assign := - Make_Assignment_Statement (Loc, - Name => - Make_Selected_Component (Loc, - Prefix => TagR, - Selector_Name => - New_Reference_To (First_Tag_Component (Full_T), Loc)), - Expression => - Unchecked_Convert_To (RTE (RE_Tag), - New_Reference_To - (Elists.Node - (First_Elmt (Access_Disp_Table (Full_T))), Loc))); - end; - - -- The previous assignment has to be done in any case - - Set_Assignment_OK (Name (Tag_Assign)); - Insert_Action (N, Tag_Assign); - end if; - - if Needs_Finalization (DesigT) - and then Needs_Finalization (T) - then - -- Generate an Adjust call if the object will be moved. In Ada - -- 2005, the object may be inherently limited, in which case - -- there is no Adjust procedure, and the object is built in - -- place. In Ada 95, the object can be limited but not - -- inherently limited if this allocator came from a return - -- statement (we're allocating the result on the secondary - -- stack). In that case, the object will be moved, so we _do_ - -- want to Adjust. - - if not Aggr_In_Place - and then not Is_Immutably_Limited_Type (T) - then - Insert_Action (N, - Make_Adjust_Call ( - Obj_Ref => - - -- An unchecked conversion is needed in the classwide - -- case because the designated type can be an ancestor - -- of the subtype mark of the allocator. - - Unchecked_Convert_To (T, - Make_Explicit_Dereference (Loc, - Prefix => New_Reference_To (Temp, Loc))), - Typ => T)); - end if; - - -- Generate: - -- Set_Finalize_Address (<PtrT>FM, <T>FD'Unrestricted_Access); - - -- Do not generate this call in the following cases: - - -- * .NET/JVM - these targets do not support address arithmetic - -- and unchecked conversion, key elements of Finalize_Address. - - -- * Alfa mode - the call is useless and results in unwanted - -- expansion. - - -- * CodePeer mode - TSS primitive Finalize_Address is not - -- created in this mode. - - if VM_Target = No_VM - and then not Alfa_Mode - and then not CodePeer_Mode - and then Present (Finalization_Master (PtrT)) - and then Present (Temp_Decl) - and then Nkind (Expression (Temp_Decl)) = N_Allocator - then - Insert_Action (N, - Make_Set_Finalize_Address_Call - (Loc => Loc, - Typ => T, - Ptr_Typ => PtrT)); - end if; - end if; - - Rewrite (N, New_Reference_To (Temp, Loc)); - Analyze_And_Resolve (N, PtrT); - - -- Ada 2005 (AI-251): Displace the pointer to reference the record - -- component containing the secondary dispatch table of the interface - -- type. - - if Is_Interface (Directly_Designated_Type (PtrT)) then - Displace_Allocator_Pointer (N); - end if; - - elsif Aggr_In_Place then - Temp := Make_Temporary (Loc, 'P', N); - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Object_Definition => New_Reference_To (PtrT, Loc), - Expression => - Make_Allocator (Loc, - Expression => New_Reference_To (Etype (Exp), Loc))); - - -- Copy the Comes_From_Source flag for the allocator we just built, - -- since logically this allocator is a replacement of the original - -- allocator node. This is for proper handling of restriction - -- No_Implicit_Heap_Allocations. - - Set_Comes_From_Source - (Expression (Temp_Decl), Comes_From_Source (N)); - - Set_No_Initialization (Expression (Temp_Decl)); - Insert_Action (N, Temp_Decl); - - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); - - -- Attach the object to the associated finalization master. Thisis - -- done manually on .NET/JVM since those compilers do no support - -- pools and cannot benefit from internally generated Allocate and - -- Deallocate procedures. - - if VM_Target /= No_VM - and then Is_Controlled (DesigT) - and then Present (Finalization_Master (PtrT)) - then - Insert_Action (N, - Make_Attach_Call - (Obj_Ref => New_Reference_To (Temp, Loc), - Ptr_Typ => PtrT)); - end if; - - Rewrite (N, New_Reference_To (Temp, Loc)); - Analyze_And_Resolve (N, PtrT); - - elsif Is_Access_Type (T) - and then Can_Never_Be_Null (T) - then - Install_Null_Excluding_Check (Exp); - - elsif Is_Access_Type (DesigT) - and then Nkind (Exp) = N_Allocator - and then Nkind (Expression (Exp)) /= N_Qualified_Expression - then - -- Apply constraint to designated subtype indication - - Apply_Constraint_Check (Expression (Exp), - Designated_Type (DesigT), - No_Sliding => True); - - if Nkind (Expression (Exp)) = N_Raise_Constraint_Error then - - -- Propagate constraint_error to enclosing allocator - - Rewrite (Exp, New_Copy (Expression (Exp))); - end if; - - else - Build_Allocate_Deallocate_Proc (N, True); - - -- If we have: - -- type A is access T1; - -- X : A := new T2'(...); - -- T1 and T2 can be different subtypes, and we might need to check - -- both constraints. First check against the type of the qualified - -- expression. - - Apply_Constraint_Check (Exp, T, No_Sliding => True); - - if Do_Range_Check (Exp) then - Set_Do_Range_Check (Exp, False); - Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed); - end if; - - -- A check is also needed in cases where the designated subtype is - -- constrained and differs from the subtype given in the qualified - -- expression. Note that the check on the qualified expression does - -- not allow sliding, but this check does (a relaxation from Ada 83). - - if Is_Constrained (DesigT) - and then not Subtypes_Statically_Match (T, DesigT) - then - Apply_Constraint_Check - (Exp, DesigT, No_Sliding => False); - - if Do_Range_Check (Exp) then - Set_Do_Range_Check (Exp, False); - Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed); - end if; - end if; - - -- For an access to unconstrained packed array, GIGI needs to see an - -- expression with a constrained subtype in order to compute the - -- proper size for the allocator. - - if Is_Array_Type (T) - and then not Is_Constrained (T) - and then Is_Packed (T) - then - declare - ConstrT : constant Entity_Id := Make_Temporary (Loc, 'A'); - Internal_Exp : constant Node_Id := Relocate_Node (Exp); - begin - Insert_Action (Exp, - Make_Subtype_Declaration (Loc, - Defining_Identifier => ConstrT, - Subtype_Indication => - Make_Subtype_From_Expr (Internal_Exp, T))); - Freeze_Itype (ConstrT, Exp); - Rewrite (Exp, OK_Convert_To (ConstrT, Internal_Exp)); - end; - end if; - - -- Ada 2005 (AI-318-02): If the initialization expression is a call - -- to a build-in-place function, then access to the allocated object - -- must be passed to the function. Currently we limit such functions - -- to those with constrained limited result subtypes, but eventually - -- we plan to expand the allowed forms of functions that are treated - -- as build-in-place. - - if Ada_Version >= Ada_2005 - and then Is_Build_In_Place_Function_Call (Exp) - then - Make_Build_In_Place_Call_In_Allocator (N, Exp); - end if; - end if; - - exception - when RE_Not_Available => - return; - end Expand_Allocator_Expression; - - ----------------------------- - -- Expand_Array_Comparison -- - ----------------------------- - - -- Expansion is only required in the case of array types. For the unpacked - -- case, an appropriate runtime routine is called. For packed cases, and - -- also in some other cases where a runtime routine cannot be called, the - -- form of the expansion is: - - -- [body for greater_nn; boolean_expression] - - -- The body is built by Make_Array_Comparison_Op, and the form of the - -- Boolean expression depends on the operator involved. - - procedure Expand_Array_Comparison (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Op1 : Node_Id := Left_Opnd (N); - Op2 : Node_Id := Right_Opnd (N); - Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); - Ctyp : constant Entity_Id := Component_Type (Typ1); - - Expr : Node_Id; - Func_Body : Node_Id; - Func_Name : Entity_Id; - - Comp : RE_Id; - - Byte_Addressable : constant Boolean := System_Storage_Unit = Byte'Size; - -- True for byte addressable target - - function Length_Less_Than_4 (Opnd : Node_Id) return Boolean; - -- Returns True if the length of the given operand is known to be less - -- than 4. Returns False if this length is known to be four or greater - -- or is not known at compile time. - - ------------------------ - -- Length_Less_Than_4 -- - ------------------------ - - function Length_Less_Than_4 (Opnd : Node_Id) return Boolean is - Otyp : constant Entity_Id := Etype (Opnd); - - begin - if Ekind (Otyp) = E_String_Literal_Subtype then - return String_Literal_Length (Otyp) < 4; - - else - declare - Ityp : constant Entity_Id := Etype (First_Index (Otyp)); - Lo : constant Node_Id := Type_Low_Bound (Ityp); - Hi : constant Node_Id := Type_High_Bound (Ityp); - Lov : Uint; - Hiv : Uint; - - begin - if Compile_Time_Known_Value (Lo) then - Lov := Expr_Value (Lo); - else - return False; - end if; - - if Compile_Time_Known_Value (Hi) then - Hiv := Expr_Value (Hi); - else - return False; - end if; - - return Hiv < Lov + 3; - end; - end if; - end Length_Less_Than_4; - - -- Start of processing for Expand_Array_Comparison - - begin - -- Deal first with unpacked case, where we can call a runtime routine - -- except that we avoid this for targets for which are not addressable - -- by bytes, and for the JVM/CIL, since they do not support direct - -- addressing of array components. - - if not Is_Bit_Packed_Array (Typ1) - and then Byte_Addressable - and then VM_Target = No_VM - then - -- The call we generate is: - - -- Compare_Array_xn[_Unaligned] - -- (left'address, right'address, left'length, right'length) <op> 0 - - -- x = U for unsigned, S for signed - -- n = 8,16,32,64 for component size - -- Add _Unaligned if length < 4 and component size is 8. - -- <op> is the standard comparison operator - - if Component_Size (Typ1) = 8 then - if Length_Less_Than_4 (Op1) - or else - Length_Less_Than_4 (Op2) - then - if Is_Unsigned_Type (Ctyp) then - Comp := RE_Compare_Array_U8_Unaligned; - else - Comp := RE_Compare_Array_S8_Unaligned; - end if; - - else - if Is_Unsigned_Type (Ctyp) then - Comp := RE_Compare_Array_U8; - else - Comp := RE_Compare_Array_S8; - end if; - end if; - - elsif Component_Size (Typ1) = 16 then - if Is_Unsigned_Type (Ctyp) then - Comp := RE_Compare_Array_U16; - else - Comp := RE_Compare_Array_S16; - end if; - - elsif Component_Size (Typ1) = 32 then - if Is_Unsigned_Type (Ctyp) then - Comp := RE_Compare_Array_U32; - else - Comp := RE_Compare_Array_S32; - end if; - - else pragma Assert (Component_Size (Typ1) = 64); - if Is_Unsigned_Type (Ctyp) then - Comp := RE_Compare_Array_U64; - else - Comp := RE_Compare_Array_S64; - end if; - end if; - - Remove_Side_Effects (Op1, Name_Req => True); - Remove_Side_Effects (Op2, Name_Req => True); - - Rewrite (Op1, - Make_Function_Call (Sloc (Op1), - Name => New_Occurrence_Of (RTE (Comp), Loc), - - Parameter_Associations => New_List ( - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Op1), - Attribute_Name => Name_Address), - - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Op2), - Attribute_Name => Name_Address), - - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Op1), - Attribute_Name => Name_Length), - - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Op2), - Attribute_Name => Name_Length)))); - - Rewrite (Op2, - Make_Integer_Literal (Sloc (Op2), - Intval => Uint_0)); - - Analyze_And_Resolve (Op1, Standard_Integer); - Analyze_And_Resolve (Op2, Standard_Integer); - return; - end if; - - -- Cases where we cannot make runtime call - - -- For (a <= b) we convert to not (a > b) - - if Chars (N) = Name_Op_Le then - Rewrite (N, - Make_Op_Not (Loc, - Right_Opnd => - Make_Op_Gt (Loc, - Left_Opnd => Op1, - Right_Opnd => Op2))); - Analyze_And_Resolve (N, Standard_Boolean); - return; - - -- For < the Boolean expression is - -- greater__nn (op2, op1) - - elsif Chars (N) = Name_Op_Lt then - Func_Body := Make_Array_Comparison_Op (Typ1, N); - - -- Switch operands - - Op1 := Right_Opnd (N); - Op2 := Left_Opnd (N); - - -- For (a >= b) we convert to not (a < b) - - elsif Chars (N) = Name_Op_Ge then - Rewrite (N, - Make_Op_Not (Loc, - Right_Opnd => - Make_Op_Lt (Loc, - Left_Opnd => Op1, - Right_Opnd => Op2))); - Analyze_And_Resolve (N, Standard_Boolean); - return; - - -- For > the Boolean expression is - -- greater__nn (op1, op2) - - else - pragma Assert (Chars (N) = Name_Op_Gt); - Func_Body := Make_Array_Comparison_Op (Typ1, N); - end if; - - Func_Name := Defining_Unit_Name (Specification (Func_Body)); - Expr := - Make_Function_Call (Loc, - Name => New_Reference_To (Func_Name, Loc), - Parameter_Associations => New_List (Op1, Op2)); - - Insert_Action (N, Func_Body); - Rewrite (N, Expr); - Analyze_And_Resolve (N, Standard_Boolean); - - exception - when RE_Not_Available => - return; - end Expand_Array_Comparison; - - --------------------------- - -- Expand_Array_Equality -- - --------------------------- - - -- Expand an equality function for multi-dimensional arrays. Here is an - -- example of such a function for Nb_Dimension = 2 - - -- function Enn (A : atyp; B : btyp) return boolean is - -- begin - -- if (A'length (1) = 0 or else A'length (2) = 0) - -- and then - -- (B'length (1) = 0 or else B'length (2) = 0) - -- then - -- return True; -- RM 4.5.2(22) - -- end if; - - -- if A'length (1) /= B'length (1) - -- or else - -- A'length (2) /= B'length (2) - -- then - -- return False; -- RM 4.5.2(23) - -- end if; - - -- declare - -- A1 : Index_T1 := A'first (1); - -- B1 : Index_T1 := B'first (1); - -- begin - -- loop - -- declare - -- A2 : Index_T2 := A'first (2); - -- B2 : Index_T2 := B'first (2); - -- begin - -- loop - -- if A (A1, A2) /= B (B1, B2) then - -- return False; - -- end if; - - -- exit when A2 = A'last (2); - -- A2 := Index_T2'succ (A2); - -- B2 := Index_T2'succ (B2); - -- end loop; - -- end; - - -- exit when A1 = A'last (1); - -- A1 := Index_T1'succ (A1); - -- B1 := Index_T1'succ (B1); - -- end loop; - -- end; - - -- return true; - -- end Enn; - - -- Note on the formal types used (atyp and btyp). If either of the arrays - -- is of a private type, we use the underlying type, and do an unchecked - -- conversion of the actual. If either of the arrays has a bound depending - -- on a discriminant, then we use the base type since otherwise we have an - -- escaped discriminant in the function. - - -- If both arrays are constrained and have the same bounds, we can generate - -- a loop with an explicit iteration scheme using a 'Range attribute over - -- the first array. - - function Expand_Array_Equality - (Nod : Node_Id; - Lhs : Node_Id; - Rhs : Node_Id; - Bodies : List_Id; - Typ : Entity_Id) return Node_Id - is - Loc : constant Source_Ptr := Sloc (Nod); - Decls : constant List_Id := New_List; - Index_List1 : constant List_Id := New_List; - Index_List2 : constant List_Id := New_List; - - Actuals : List_Id; - Formals : List_Id; - Func_Name : Entity_Id; - Func_Body : Node_Id; - - A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); - B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); - - Ltyp : Entity_Id; - Rtyp : Entity_Id; - -- The parameter types to be used for the formals - - function Arr_Attr - (Arr : Entity_Id; - Nam : Name_Id; - Num : Int) return Node_Id; - -- This builds the attribute reference Arr'Nam (Expr) - - function Component_Equality (Typ : Entity_Id) return Node_Id; - -- Create one statement to compare corresponding components, designated - -- by a full set of indexes. - - function Get_Arg_Type (N : Node_Id) return Entity_Id; - -- Given one of the arguments, computes the appropriate type to be used - -- for that argument in the corresponding function formal - - function Handle_One_Dimension - (N : Int; - Index : Node_Id) return Node_Id; - -- This procedure returns the following code - -- - -- declare - -- Bn : Index_T := B'First (N); - -- begin - -- loop - -- xxx - -- exit when An = A'Last (N); - -- An := Index_T'Succ (An) - -- Bn := Index_T'Succ (Bn) - -- end loop; - -- end; - -- - -- If both indexes are constrained and identical, the procedure - -- returns a simpler loop: - -- - -- for An in A'Range (N) loop - -- xxx - -- end loop - -- - -- N is the dimension for which we are generating a loop. Index is the - -- N'th index node, whose Etype is Index_Type_n in the above code. The - -- xxx statement is either the loop or declare for the next dimension - -- or if this is the last dimension the comparison of corresponding - -- components of the arrays. - -- - -- The actual way the code works is to return the comparison of - -- corresponding components for the N+1 call. That's neater! - - function Test_Empty_Arrays return Node_Id; - -- This function constructs the test for both arrays being empty - -- (A'length (1) = 0 or else A'length (2) = 0 or else ...) - -- and then - -- (B'length (1) = 0 or else B'length (2) = 0 or else ...) - - function Test_Lengths_Correspond return Node_Id; - -- This function constructs the test for arrays having different lengths - -- in at least one index position, in which case the resulting code is: - - -- A'length (1) /= B'length (1) - -- or else - -- A'length (2) /= B'length (2) - -- or else - -- ... - - -------------- - -- Arr_Attr -- - -------------- - - function Arr_Attr - (Arr : Entity_Id; - Nam : Name_Id; - Num : Int) return Node_Id - is - begin - return - Make_Attribute_Reference (Loc, - Attribute_Name => Nam, - Prefix => New_Reference_To (Arr, Loc), - Expressions => New_List (Make_Integer_Literal (Loc, Num))); - end Arr_Attr; - - ------------------------ - -- Component_Equality -- - ------------------------ - - function Component_Equality (Typ : Entity_Id) return Node_Id is - Test : Node_Id; - L, R : Node_Id; - - begin - -- if a(i1...) /= b(j1...) then return false; end if; - - L := - Make_Indexed_Component (Loc, - Prefix => Make_Identifier (Loc, Chars (A)), - Expressions => Index_List1); - - R := - Make_Indexed_Component (Loc, - Prefix => Make_Identifier (Loc, Chars (B)), - Expressions => Index_List2); - - Test := Expand_Composite_Equality - (Nod, Component_Type (Typ), L, R, Decls); - - -- If some (sub)component is an unchecked_union, the whole operation - -- will raise program error. - - if Nkind (Test) = N_Raise_Program_Error then - - -- This node is going to be inserted at a location where a - -- statement is expected: clear its Etype so analysis will set - -- it to the expected Standard_Void_Type. - - Set_Etype (Test, Empty); - return Test; - - else - return - Make_Implicit_If_Statement (Nod, - Condition => Make_Op_Not (Loc, Right_Opnd => Test), - Then_Statements => New_List ( - Make_Simple_Return_Statement (Loc, - Expression => New_Occurrence_Of (Standard_False, Loc)))); - end if; - end Component_Equality; - - ------------------ - -- Get_Arg_Type -- - ------------------ - - function Get_Arg_Type (N : Node_Id) return Entity_Id is - T : Entity_Id; - X : Node_Id; - - begin - T := Etype (N); - - if No (T) then - return Typ; - - else - T := Underlying_Type (T); - - X := First_Index (T); - while Present (X) loop - if Denotes_Discriminant (Type_Low_Bound (Etype (X))) - or else - Denotes_Discriminant (Type_High_Bound (Etype (X))) - then - T := Base_Type (T); - exit; - end if; - - Next_Index (X); - end loop; - - return T; - end if; - end Get_Arg_Type; - - -------------------------- - -- Handle_One_Dimension -- - --------------------------- - - function Handle_One_Dimension - (N : Int; - Index : Node_Id) return Node_Id - is - Need_Separate_Indexes : constant Boolean := - Ltyp /= Rtyp - or else not Is_Constrained (Ltyp); - -- If the index types are identical, and we are working with - -- constrained types, then we can use the same index for both - -- of the arrays. - - An : constant Entity_Id := Make_Temporary (Loc, 'A'); - - Bn : Entity_Id; - Index_T : Entity_Id; - Stm_List : List_Id; - Loop_Stm : Node_Id; - - begin - if N > Number_Dimensions (Ltyp) then - return Component_Equality (Ltyp); - end if; - - -- Case where we generate a loop - - Index_T := Base_Type (Etype (Index)); - - if Need_Separate_Indexes then - Bn := Make_Temporary (Loc, 'B'); - else - Bn := An; - end if; - - Append (New_Reference_To (An, Loc), Index_List1); - Append (New_Reference_To (Bn, Loc), Index_List2); - - Stm_List := New_List ( - Handle_One_Dimension (N + 1, Next_Index (Index))); - - if Need_Separate_Indexes then - - -- Generate guard for loop, followed by increments of indexes - - Append_To (Stm_List, - Make_Exit_Statement (Loc, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => New_Reference_To (An, Loc), - Right_Opnd => Arr_Attr (A, Name_Last, N)))); - - Append_To (Stm_List, - Make_Assignment_Statement (Loc, - Name => New_Reference_To (An, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Index_T, Loc), - Attribute_Name => Name_Succ, - Expressions => New_List (New_Reference_To (An, Loc))))); - - Append_To (Stm_List, - Make_Assignment_Statement (Loc, - Name => New_Reference_To (Bn, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Index_T, Loc), - Attribute_Name => Name_Succ, - Expressions => New_List (New_Reference_To (Bn, Loc))))); - end if; - - -- If separate indexes, we need a declare block for An and Bn, and a - -- loop without an iteration scheme. - - if Need_Separate_Indexes then - Loop_Stm := - Make_Implicit_Loop_Statement (Nod, Statements => Stm_List); - - return - Make_Block_Statement (Loc, - Declarations => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => An, - Object_Definition => New_Reference_To (Index_T, Loc), - Expression => Arr_Attr (A, Name_First, N)), - - Make_Object_Declaration (Loc, - Defining_Identifier => Bn, - Object_Definition => New_Reference_To (Index_T, Loc), - Expression => Arr_Attr (B, Name_First, N))), - - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List (Loop_Stm))); - - -- If no separate indexes, return loop statement with explicit - -- iteration scheme on its own - - else - Loop_Stm := - Make_Implicit_Loop_Statement (Nod, - Statements => Stm_List, - Iteration_Scheme => - Make_Iteration_Scheme (Loc, - Loop_Parameter_Specification => - Make_Loop_Parameter_Specification (Loc, - Defining_Identifier => An, - Discrete_Subtype_Definition => - Arr_Attr (A, Name_Range, N)))); - return Loop_Stm; - end if; - end Handle_One_Dimension; - - ----------------------- - -- Test_Empty_Arrays -- - ----------------------- - - function Test_Empty_Arrays return Node_Id is - Alist : Node_Id; - Blist : Node_Id; - - Atest : Node_Id; - Btest : Node_Id; - - begin - Alist := Empty; - Blist := Empty; - for J in 1 .. Number_Dimensions (Ltyp) loop - Atest := - Make_Op_Eq (Loc, - Left_Opnd => Arr_Attr (A, Name_Length, J), - Right_Opnd => Make_Integer_Literal (Loc, 0)); - - Btest := - Make_Op_Eq (Loc, - Left_Opnd => Arr_Attr (B, Name_Length, J), - Right_Opnd => Make_Integer_Literal (Loc, 0)); - - if No (Alist) then - Alist := Atest; - Blist := Btest; - - else - Alist := - Make_Or_Else (Loc, - Left_Opnd => Relocate_Node (Alist), - Right_Opnd => Atest); - - Blist := - Make_Or_Else (Loc, - Left_Opnd => Relocate_Node (Blist), - Right_Opnd => Btest); - end if; - end loop; - - return - Make_And_Then (Loc, - Left_Opnd => Alist, - Right_Opnd => Blist); - end Test_Empty_Arrays; - - ----------------------------- - -- Test_Lengths_Correspond -- - ----------------------------- - - function Test_Lengths_Correspond return Node_Id is - Result : Node_Id; - Rtest : Node_Id; - - begin - Result := Empty; - for J in 1 .. Number_Dimensions (Ltyp) loop - Rtest := - Make_Op_Ne (Loc, - Left_Opnd => Arr_Attr (A, Name_Length, J), - Right_Opnd => Arr_Attr (B, Name_Length, J)); - - if No (Result) then - Result := Rtest; - else - Result := - Make_Or_Else (Loc, - Left_Opnd => Relocate_Node (Result), - Right_Opnd => Rtest); - end if; - end loop; - - return Result; - end Test_Lengths_Correspond; - - -- Start of processing for Expand_Array_Equality - - begin - Ltyp := Get_Arg_Type (Lhs); - Rtyp := Get_Arg_Type (Rhs); - - -- For now, if the argument types are not the same, go to the base type, - -- since the code assumes that the formals have the same type. This is - -- fixable in future ??? - - if Ltyp /= Rtyp then - Ltyp := Base_Type (Ltyp); - Rtyp := Base_Type (Rtyp); - pragma Assert (Ltyp = Rtyp); - end if; - - -- Build list of formals for function - - Formals := New_List ( - Make_Parameter_Specification (Loc, - Defining_Identifier => A, - Parameter_Type => New_Reference_To (Ltyp, Loc)), - - Make_Parameter_Specification (Loc, - Defining_Identifier => B, - Parameter_Type => New_Reference_To (Rtyp, Loc))); - - Func_Name := Make_Temporary (Loc, 'E'); - - -- Build statement sequence for function - - Func_Body := - Make_Subprogram_Body (Loc, - Specification => - Make_Function_Specification (Loc, - Defining_Unit_Name => Func_Name, - Parameter_Specifications => Formals, - Result_Definition => New_Reference_To (Standard_Boolean, Loc)), - - Declarations => Decls, - - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List ( - - Make_Implicit_If_Statement (Nod, - Condition => Test_Empty_Arrays, - Then_Statements => New_List ( - Make_Simple_Return_Statement (Loc, - Expression => - New_Occurrence_Of (Standard_True, Loc)))), - - Make_Implicit_If_Statement (Nod, - Condition => Test_Lengths_Correspond, - Then_Statements => New_List ( - Make_Simple_Return_Statement (Loc, - Expression => - New_Occurrence_Of (Standard_False, Loc)))), - - Handle_One_Dimension (1, First_Index (Ltyp)), - - Make_Simple_Return_Statement (Loc, - Expression => New_Occurrence_Of (Standard_True, Loc))))); - - Set_Has_Completion (Func_Name, True); - Set_Is_Inlined (Func_Name); - - -- If the array type is distinct from the type of the arguments, it - -- is the full view of a private type. Apply an unchecked conversion - -- to insure that analysis of the call succeeds. - - declare - L, R : Node_Id; - - begin - L := Lhs; - R := Rhs; - - if No (Etype (Lhs)) - or else Base_Type (Etype (Lhs)) /= Base_Type (Ltyp) - then - L := OK_Convert_To (Ltyp, Lhs); - end if; - - if No (Etype (Rhs)) - or else Base_Type (Etype (Rhs)) /= Base_Type (Rtyp) - then - R := OK_Convert_To (Rtyp, Rhs); - end if; - - Actuals := New_List (L, R); - end; - - Append_To (Bodies, Func_Body); - - return - Make_Function_Call (Loc, - Name => New_Reference_To (Func_Name, Loc), - Parameter_Associations => Actuals); - end Expand_Array_Equality; - - ----------------------------- - -- Expand_Boolean_Operator -- - ----------------------------- - - -- Note that we first get the actual subtypes of the operands, since we - -- always want to deal with types that have bounds. - - procedure Expand_Boolean_Operator (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - -- Special case of bit packed array where both operands are known to be - -- properly aligned. In this case we use an efficient run time routine - -- to carry out the operation (see System.Bit_Ops). - - if Is_Bit_Packed_Array (Typ) - and then not Is_Possibly_Unaligned_Object (Left_Opnd (N)) - and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) - then - Expand_Packed_Boolean_Operator (N); - return; - end if; - - -- For the normal non-packed case, the general expansion is to build - -- function for carrying out the comparison (use Make_Boolean_Array_Op) - -- and then inserting it into the tree. The original operator node is - -- then rewritten as a call to this function. We also use this in the - -- packed case if either operand is a possibly unaligned object. - - declare - Loc : constant Source_Ptr := Sloc (N); - L : constant Node_Id := Relocate_Node (Left_Opnd (N)); - R : constant Node_Id := Relocate_Node (Right_Opnd (N)); - Func_Body : Node_Id; - Func_Name : Entity_Id; - - begin - Convert_To_Actual_Subtype (L); - Convert_To_Actual_Subtype (R); - Ensure_Defined (Etype (L), N); - Ensure_Defined (Etype (R), N); - Apply_Length_Check (R, Etype (L)); - - if Nkind (N) = N_Op_Xor then - Silly_Boolean_Array_Xor_Test (N, Etype (L)); - end if; - - if Nkind (Parent (N)) = N_Assignment_Statement - and then Safe_In_Place_Array_Op (Name (Parent (N)), L, R) - then - Build_Boolean_Array_Proc_Call (Parent (N), L, R); - - elsif Nkind (Parent (N)) = N_Op_Not - and then Nkind (N) = N_Op_And - and then - Safe_In_Place_Array_Op (Name (Parent (Parent (N))), L, R) - then - return; - else - - Func_Body := Make_Boolean_Array_Op (Etype (L), N); - Func_Name := Defining_Unit_Name (Specification (Func_Body)); - Insert_Action (N, Func_Body); - - -- Now rewrite the expression with a call - - Rewrite (N, - Make_Function_Call (Loc, - Name => New_Reference_To (Func_Name, Loc), - Parameter_Associations => - New_List ( - L, - Make_Type_Conversion - (Loc, New_Reference_To (Etype (L), Loc), R)))); - - Analyze_And_Resolve (N, Typ); - end if; - end; - end Expand_Boolean_Operator; - - ------------------------------------------------ - -- Expand_Compare_Minimize_Eliminate_Overflow -- - ------------------------------------------------ - - procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - - Result_Type : constant Entity_Id := Etype (N); - -- Capture result type (could be a derived boolean type) - - Llo, Lhi : Uint; - Rlo, Rhi : Uint; - - LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); - -- Entity for Long_Long_Integer'Base - - Check : constant Overflow_Mode_Type := Overflow_Check_Mode; - -- Current overflow checking mode - - procedure Set_True; - procedure Set_False; - -- These procedures rewrite N with an occurrence of Standard_True or - -- Standard_False, and then makes a call to Warn_On_Known_Condition. - - --------------- - -- Set_False -- - --------------- - - procedure Set_False is - begin - Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); - Warn_On_Known_Condition (N); - end Set_False; - - -------------- - -- Set_True -- - -------------- - - procedure Set_True is - begin - Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); - Warn_On_Known_Condition (N); - end Set_True; - - -- Start of processing for Expand_Compare_Minimize_Eliminate_Overflow - - begin - -- Nothing to do unless we have a comparison operator with operands - -- that are signed integer types, and we are operating in either - -- MINIMIZED or ELIMINATED overflow checking mode. - - if Nkind (N) not in N_Op_Compare - or else Check not in Minimized_Or_Eliminated - or else not Is_Signed_Integer_Type (Etype (Left_Opnd (N))) - then - return; - end if; - - -- OK, this is the case we are interested in. First step is to process - -- our operands using the Minimize_Eliminate circuitry which applies - -- this processing to the two operand subtrees. - - Minimize_Eliminate_Overflows - (Left_Opnd (N), Llo, Lhi, Top_Level => False); - Minimize_Eliminate_Overflows - (Right_Opnd (N), Rlo, Rhi, Top_Level => False); - - -- See if the range information decides the result of the comparison. - -- We can only do this if we in fact have full range information (which - -- won't be the case if either operand is bignum at this stage). - - if Llo /= No_Uint and then Rlo /= No_Uint then - case N_Op_Compare (Nkind (N)) is - when N_Op_Eq => - if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then - Set_True; - elsif Llo > Rhi or else Lhi < Rlo then - Set_False; - end if; - - when N_Op_Ge => - if Llo >= Rhi then - Set_True; - elsif Lhi < Rlo then - Set_False; - end if; - - when N_Op_Gt => - if Llo > Rhi then - Set_True; - elsif Lhi <= Rlo then - Set_False; - end if; - - when N_Op_Le => - if Llo > Rhi then - Set_False; - elsif Lhi <= Rlo then - Set_True; - end if; - - when N_Op_Lt => - if Llo >= Rhi then - Set_False; - elsif Lhi < Rlo then - Set_True; - end if; - - when N_Op_Ne => - if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then - Set_False; - elsif Llo > Rhi or else Lhi < Rlo then - Set_True; - end if; - end case; - - -- All done if we did the rewrite - - if Nkind (N) not in N_Op_Compare then - return; - end if; - end if; - - -- Otherwise, time to do the comparison - - declare - Ltype : constant Entity_Id := Etype (Left_Opnd (N)); - Rtype : constant Entity_Id := Etype (Right_Opnd (N)); - - begin - -- If the two operands have the same signed integer type we are - -- all set, nothing more to do. This is the case where either - -- both operands were unchanged, or we rewrote both of them to - -- be Long_Long_Integer. - - -- Note: Entity for the comparison may be wrong, but it's not worth - -- the effort to change it, since the back end does not use it. - - if Is_Signed_Integer_Type (Ltype) - and then Base_Type (Ltype) = Base_Type (Rtype) - then - return; - - -- Here if bignums are involved (can only happen in ELIMINATED mode) - - elsif Is_RTE (Ltype, RE_Bignum) or else Is_RTE (Rtype, RE_Bignum) then - declare - Left : Node_Id := Left_Opnd (N); - Right : Node_Id := Right_Opnd (N); - -- Bignum references for left and right operands - - begin - if not Is_RTE (Ltype, RE_Bignum) then - Left := Convert_To_Bignum (Left); - elsif not Is_RTE (Rtype, RE_Bignum) then - Right := Convert_To_Bignum (Right); - end if; - - -- We rewrite our node with: - - -- do - -- Bnn : Result_Type; - -- declare - -- M : Mark_Id := SS_Mark; - -- begin - -- Bnn := Big_xx (Left, Right); (xx = EQ, NT etc) - -- SS_Release (M); - -- end; - -- in - -- Bnn - -- end - - declare - Blk : constant Node_Id := Make_Bignum_Block (Loc); - Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); - Ent : RE_Id; - - begin - case N_Op_Compare (Nkind (N)) is - when N_Op_Eq => Ent := RE_Big_EQ; - when N_Op_Ge => Ent := RE_Big_GE; - when N_Op_Gt => Ent := RE_Big_GT; - when N_Op_Le => Ent := RE_Big_LE; - when N_Op_Lt => Ent := RE_Big_LT; - when N_Op_Ne => Ent := RE_Big_NE; - end case; - - -- Insert assignment to Bnn into the bignum block - - Insert_Before - (First (Statements (Handled_Statement_Sequence (Blk))), - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Bnn, Loc), - Expression => - Make_Function_Call (Loc, - Name => - New_Occurrence_Of (RTE (Ent), Loc), - Parameter_Associations => New_List (Left, Right)))); - - -- Now do the rewrite with expression actions - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Actions => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => Bnn, - Object_Definition => - New_Occurrence_Of (Result_Type, Loc)), - Blk), - Expression => New_Occurrence_Of (Bnn, Loc))); - Analyze_And_Resolve (N, Result_Type); - end; - end; - - -- No bignums involved, but types are different, so we must have - -- rewritten one of the operands as a Long_Long_Integer but not - -- the other one. - - -- If left operand is Long_Long_Integer, convert right operand - -- and we are done (with a comparison of two Long_Long_Integers). - - elsif Ltype = LLIB then - Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); - Analyze_And_Resolve (Right_Opnd (N), LLIB, Suppress => All_Checks); - return; - - -- If right operand is Long_Long_Integer, convert left operand - -- and we are done (with a comparison of two Long_Long_Integers). - - -- This is the only remaining possibility - - else pragma Assert (Rtype = LLIB); - Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); - Analyze_And_Resolve (Left_Opnd (N), LLIB, Suppress => All_Checks); - return; - end if; - end; - end Expand_Compare_Minimize_Eliminate_Overflow; - - ------------------------------- - -- Expand_Composite_Equality -- - ------------------------------- - - -- This function is only called for comparing internal fields of composite - -- types when these fields are themselves composites. This is a special - -- case because it is not possible to respect normal Ada visibility rules. - - function Expand_Composite_Equality - (Nod : Node_Id; - Typ : Entity_Id; - Lhs : Node_Id; - Rhs : Node_Id; - Bodies : List_Id) return Node_Id - is - Loc : constant Source_Ptr := Sloc (Nod); - Full_Type : Entity_Id; - Prim : Elmt_Id; - Eq_Op : Entity_Id; - - function Find_Primitive_Eq return Node_Id; - -- AI05-0123: Locate primitive equality for type if it exists, and - -- build the corresponding call. If operation is abstract, replace - -- call with an explicit raise. Return Empty if there is no primitive. - - ----------------------- - -- Find_Primitive_Eq -- - ----------------------- - - function Find_Primitive_Eq return Node_Id is - Prim_E : Elmt_Id; - Prim : Node_Id; - - begin - Prim_E := First_Elmt (Collect_Primitive_Operations (Typ)); - while Present (Prim_E) loop - Prim := Node (Prim_E); - - -- Locate primitive equality with the right signature - - if Chars (Prim) = Name_Op_Eq - and then Etype (First_Formal (Prim)) = - Etype (Next_Formal (First_Formal (Prim))) - and then Etype (Prim) = Standard_Boolean - then - if Is_Abstract_Subprogram (Prim) then - return - Make_Raise_Program_Error (Loc, - Reason => PE_Explicit_Raise); - - else - return - Make_Function_Call (Loc, - Name => New_Reference_To (Prim, Loc), - Parameter_Associations => New_List (Lhs, Rhs)); - end if; - end if; - - Next_Elmt (Prim_E); - end loop; - - -- If not found, predefined operation will be used - - return Empty; - end Find_Primitive_Eq; - - -- Start of processing for Expand_Composite_Equality - - begin - if Is_Private_Type (Typ) then - Full_Type := Underlying_Type (Typ); - else - Full_Type := Typ; - end if; - - -- Defense against malformed private types with no completion the error - -- will be diagnosed later by check_completion - - if No (Full_Type) then - return New_Reference_To (Standard_False, Loc); - end if; - - Full_Type := Base_Type (Full_Type); - - if Is_Array_Type (Full_Type) then - - -- If the operand is an elementary type other than a floating-point - -- type, then we can simply use the built-in block bitwise equality, - -- since the predefined equality operators always apply and bitwise - -- equality is fine for all these cases. - - if Is_Elementary_Type (Component_Type (Full_Type)) - and then not Is_Floating_Point_Type (Component_Type (Full_Type)) - then - return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); - - -- For composite component types, and floating-point types, use the - -- expansion. This deals with tagged component types (where we use - -- the applicable equality routine) and floating-point, (where we - -- need to worry about negative zeroes), and also the case of any - -- composite type recursively containing such fields. - - else - return Expand_Array_Equality (Nod, Lhs, Rhs, Bodies, Full_Type); - end if; - - elsif Is_Tagged_Type (Full_Type) then - - -- Call the primitive operation "=" of this type - - if Is_Class_Wide_Type (Full_Type) then - Full_Type := Root_Type (Full_Type); - end if; - - -- If this is derived from an untagged private type completed with a - -- tagged type, it does not have a full view, so we use the primitive - -- operations of the private type. This check should no longer be - -- necessary when these types receive their full views ??? - - if Is_Private_Type (Typ) - and then not Is_Tagged_Type (Typ) - and then not Is_Controlled (Typ) - and then Is_Derived_Type (Typ) - and then No (Full_View (Typ)) - then - Prim := First_Elmt (Collect_Primitive_Operations (Typ)); - else - Prim := First_Elmt (Primitive_Operations (Full_Type)); - end if; - - loop - Eq_Op := Node (Prim); - exit when Chars (Eq_Op) = Name_Op_Eq - and then Etype (First_Formal (Eq_Op)) = - Etype (Next_Formal (First_Formal (Eq_Op))) - and then Base_Type (Etype (Eq_Op)) = Standard_Boolean; - Next_Elmt (Prim); - pragma Assert (Present (Prim)); - end loop; - - Eq_Op := Node (Prim); - - return - Make_Function_Call (Loc, - Name => New_Reference_To (Eq_Op, Loc), - Parameter_Associations => - New_List - (Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Lhs), - Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Rhs))); - - elsif Is_Record_Type (Full_Type) then - Eq_Op := TSS (Full_Type, TSS_Composite_Equality); - - if Present (Eq_Op) then - if Etype (First_Formal (Eq_Op)) /= Full_Type then - - -- Inherited equality from parent type. Convert the actuals to - -- match signature of operation. - - declare - T : constant Entity_Id := Etype (First_Formal (Eq_Op)); - - begin - return - Make_Function_Call (Loc, - Name => New_Reference_To (Eq_Op, Loc), - Parameter_Associations => New_List ( - OK_Convert_To (T, Lhs), - OK_Convert_To (T, Rhs))); - end; - - else - -- Comparison between Unchecked_Union components - - if Is_Unchecked_Union (Full_Type) then - declare - Lhs_Type : Node_Id := Full_Type; - Rhs_Type : Node_Id := Full_Type; - Lhs_Discr_Val : Node_Id; - Rhs_Discr_Val : Node_Id; - - begin - -- Lhs subtype - - if Nkind (Lhs) = N_Selected_Component then - Lhs_Type := Etype (Entity (Selector_Name (Lhs))); - end if; - - -- Rhs subtype - - if Nkind (Rhs) = N_Selected_Component then - Rhs_Type := Etype (Entity (Selector_Name (Rhs))); - end if; - - -- Lhs of the composite equality - - if Is_Constrained (Lhs_Type) then - - -- Since the enclosing record type can never be an - -- Unchecked_Union (this code is executed for records - -- that do not have variants), we may reference its - -- discriminant(s). - - if Nkind (Lhs) = N_Selected_Component - and then Has_Per_Object_Constraint ( - Entity (Selector_Name (Lhs))) - then - Lhs_Discr_Val := - Make_Selected_Component (Loc, - Prefix => Prefix (Lhs), - Selector_Name => - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Lhs_Type), - Lhs_Type, - Stored_Constraint (Lhs_Type)))); - - else - Lhs_Discr_Val := - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Lhs_Type), - Lhs_Type, - Stored_Constraint (Lhs_Type))); - - end if; - else - -- It is not possible to infer the discriminant since - -- the subtype is not constrained. - - return - Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction); - end if; - - -- Rhs of the composite equality - - if Is_Constrained (Rhs_Type) then - if Nkind (Rhs) = N_Selected_Component - and then Has_Per_Object_Constraint - (Entity (Selector_Name (Rhs))) - then - Rhs_Discr_Val := - Make_Selected_Component (Loc, - Prefix => Prefix (Rhs), - Selector_Name => - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Rhs_Type), - Rhs_Type, - Stored_Constraint (Rhs_Type)))); - - else - Rhs_Discr_Val := - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Rhs_Type), - Rhs_Type, - Stored_Constraint (Rhs_Type))); - - end if; - else - return - Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction); - end if; - - -- Call the TSS equality function with the inferred - -- discriminant values. - - return - Make_Function_Call (Loc, - Name => New_Reference_To (Eq_Op, Loc), - Parameter_Associations => New_List ( - Lhs, - Rhs, - Lhs_Discr_Val, - Rhs_Discr_Val)); - end; - - else - return - Make_Function_Call (Loc, - Name => New_Reference_To (Eq_Op, Loc), - Parameter_Associations => New_List (Lhs, Rhs)); - end if; - end if; - - -- Equality composes in Ada 2012 for untagged record types. It also - -- composes for bounded strings, because they are part of the - -- predefined environment. We could make it compose for bounded - -- strings by making them tagged, or by making sure all subcomponents - -- are set to the same value, even when not used. Instead, we have - -- this special case in the compiler, because it's more efficient. - - elsif Ada_Version >= Ada_2012 or else Is_Bounded_String (Typ) then - - -- if no TSS has been created for the type, check whether there is - -- a primitive equality declared for it. - - declare - Op : constant Node_Id := Find_Primitive_Eq; - - begin - -- Use user-defined primitive if it exists, otherwise use - -- predefined equality. - - if Present (Op) then - return Op; - else - return Make_Op_Eq (Loc, Lhs, Rhs); - end if; - end; - - else - return Expand_Record_Equality (Nod, Full_Type, Lhs, Rhs, Bodies); - end if; - - else - -- If not array or record type, it is predefined equality. - - return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); - end if; - end Expand_Composite_Equality; - - ------------------------ - -- Expand_Concatenate -- - ------------------------ - - procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id) is - Loc : constant Source_Ptr := Sloc (Cnode); - - Atyp : constant Entity_Id := Base_Type (Etype (Cnode)); - -- Result type of concatenation - - Ctyp : constant Entity_Id := Base_Type (Component_Type (Etype (Cnode))); - -- Component type. Elements of this component type can appear as one - -- of the operands of concatenation as well as arrays. - - Istyp : constant Entity_Id := Etype (First_Index (Atyp)); - -- Index subtype - - Ityp : constant Entity_Id := Base_Type (Istyp); - -- Index type. This is the base type of the index subtype, and is used - -- for all computed bounds (which may be out of range of Istyp in the - -- case of null ranges). - - Artyp : Entity_Id; - -- This is the type we use to do arithmetic to compute the bounds and - -- lengths of operands. The choice of this type is a little subtle and - -- is discussed in a separate section at the start of the body code. - - Concatenation_Error : exception; - -- Raised if concatenation is sure to raise a CE - - Result_May_Be_Null : Boolean := True; - -- Reset to False if at least one operand is encountered which is known - -- at compile time to be non-null. Used for handling the special case - -- of setting the high bound to the last operand high bound for a null - -- result, thus ensuring a proper high bound in the super-flat case. - - N : constant Nat := List_Length (Opnds); - -- Number of concatenation operands including possibly null operands - - NN : Nat := 0; - -- Number of operands excluding any known to be null, except that the - -- last operand is always retained, in case it provides the bounds for - -- a null result. - - Opnd : Node_Id; - -- Current operand being processed in the loop through operands. After - -- this loop is complete, always contains the last operand (which is not - -- the same as Operands (NN), since null operands are skipped). - - -- Arrays describing the operands, only the first NN entries of each - -- array are set (NN < N when we exclude known null operands). - - Is_Fixed_Length : array (1 .. N) of Boolean; - -- True if length of corresponding operand known at compile time - - Operands : array (1 .. N) of Node_Id; - -- Set to the corresponding entry in the Opnds list (but note that null - -- operands are excluded, so not all entries in the list are stored). - - Fixed_Length : array (1 .. N) of Uint; - -- Set to length of operand. Entries in this array are set only if the - -- corresponding entry in Is_Fixed_Length is True. - - Opnd_Low_Bound : array (1 .. N) of Node_Id; - -- Set to lower bound of operand. Either an integer literal in the case - -- where the bound is known at compile time, else actual lower bound. - -- The operand low bound is of type Ityp. - - Var_Length : array (1 .. N) of Entity_Id; - -- Set to an entity of type Natural that contains the length of an - -- operand whose length is not known at compile time. Entries in this - -- array are set only if the corresponding entry in Is_Fixed_Length - -- is False. The entity is of type Artyp. - - Aggr_Length : array (0 .. N) of Node_Id; - -- The J'th entry in an expression node that represents the total length - -- of operands 1 through J. It is either an integer literal node, or a - -- reference to a constant entity with the right value, so it is fine - -- to just do a Copy_Node to get an appropriate copy. The extra zero'th - -- entry always is set to zero. The length is of type Artyp. - - Low_Bound : Node_Id; - -- A tree node representing the low bound of the result (of type Ityp). - -- This is either an integer literal node, or an identifier reference to - -- a constant entity initialized to the appropriate value. - - Last_Opnd_Low_Bound : Node_Id; - -- A tree node representing the low bound of the last operand. This - -- need only be set if the result could be null. It is used for the - -- special case of setting the right low bound for a null result. - -- This is of type Ityp. - - Last_Opnd_High_Bound : Node_Id; - -- A tree node representing the high bound of the last operand. This - -- need only be set if the result could be null. It is used for the - -- special case of setting the right high bound for a null result. - -- This is of type Ityp. - - High_Bound : Node_Id; - -- A tree node representing the high bound of the result (of type Ityp) - - Result : Node_Id; - -- Result of the concatenation (of type Ityp) - - Actions : constant List_Id := New_List; - -- Collect actions to be inserted - - Known_Non_Null_Operand_Seen : Boolean; - -- Set True during generation of the assignments of operands into - -- result once an operand known to be non-null has been seen. - - function Make_Artyp_Literal (Val : Nat) return Node_Id; - -- This function makes an N_Integer_Literal node that is returned in - -- analyzed form with the type set to Artyp. Importantly this literal - -- is not flagged as static, so that if we do computations with it that - -- result in statically detected out of range conditions, we will not - -- generate error messages but instead warning messages. - - function To_Artyp (X : Node_Id) return Node_Id; - -- Given a node of type Ityp, returns the corresponding value of type - -- Artyp. For non-enumeration types, this is a plain integer conversion. - -- For enum types, the Pos of the value is returned. - - function To_Ityp (X : Node_Id) return Node_Id; - -- The inverse function (uses Val in the case of enumeration types) - - ------------------------ - -- Make_Artyp_Literal -- - ------------------------ - - function Make_Artyp_Literal (Val : Nat) return Node_Id is - Result : constant Node_Id := Make_Integer_Literal (Loc, Val); - begin - Set_Etype (Result, Artyp); - Set_Analyzed (Result, True); - Set_Is_Static_Expression (Result, False); - return Result; - end Make_Artyp_Literal; - - -------------- - -- To_Artyp -- - -------------- - - function To_Artyp (X : Node_Id) return Node_Id is - begin - if Ityp = Base_Type (Artyp) then - return X; - - elsif Is_Enumeration_Type (Ityp) then - return - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Ityp, Loc), - Attribute_Name => Name_Pos, - Expressions => New_List (X)); - - else - return Convert_To (Artyp, X); - end if; - end To_Artyp; - - ------------- - -- To_Ityp -- - ------------- - - function To_Ityp (X : Node_Id) return Node_Id is - begin - if Is_Enumeration_Type (Ityp) then - return - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Ityp, Loc), - Attribute_Name => Name_Val, - Expressions => New_List (X)); - - -- Case where we will do a type conversion - - else - if Ityp = Base_Type (Artyp) then - return X; - else - return Convert_To (Ityp, X); - end if; - end if; - end To_Ityp; - - -- Local Declarations - - Opnd_Typ : Entity_Id; - Ent : Entity_Id; - Len : Uint; - J : Nat; - Clen : Node_Id; - Set : Boolean; - - -- Start of processing for Expand_Concatenate - - begin - -- Choose an appropriate computational type - - -- We will be doing calculations of lengths and bounds in this routine - -- and computing one from the other in some cases, e.g. getting the high - -- bound by adding the length-1 to the low bound. - - -- We can't just use the index type, or even its base type for this - -- purpose for two reasons. First it might be an enumeration type which - -- is not suitable for computations of any kind, and second it may - -- simply not have enough range. For example if the index type is - -- -128..+127 then lengths can be up to 256, which is out of range of - -- the type. - - -- For enumeration types, we can simply use Standard_Integer, this is - -- sufficient since the actual number of enumeration literals cannot - -- possibly exceed the range of integer (remember we will be doing the - -- arithmetic with POS values, not representation values). - - if Is_Enumeration_Type (Ityp) then - Artyp := Standard_Integer; - - -- If index type is Positive, we use the standard unsigned type, to give - -- more room on the top of the range, obviating the need for an overflow - -- check when creating the upper bound. This is needed to avoid junk - -- overflow checks in the common case of String types. - - -- ??? Disabled for now - - -- elsif Istyp = Standard_Positive then - -- Artyp := Standard_Unsigned; - - -- For modular types, we use a 32-bit modular type for types whose size - -- is in the range 1-31 bits. For 32-bit unsigned types, we use the - -- identity type, and for larger unsigned types we use 64-bits. - - elsif Is_Modular_Integer_Type (Ityp) then - if RM_Size (Ityp) < RM_Size (Standard_Unsigned) then - Artyp := Standard_Unsigned; - elsif RM_Size (Ityp) = RM_Size (Standard_Unsigned) then - Artyp := Ityp; - else - Artyp := RTE (RE_Long_Long_Unsigned); - end if; - - -- Similar treatment for signed types - - else - if RM_Size (Ityp) < RM_Size (Standard_Integer) then - Artyp := Standard_Integer; - elsif RM_Size (Ityp) = RM_Size (Standard_Integer) then - Artyp := Ityp; - else - Artyp := Standard_Long_Long_Integer; - end if; - end if; - - -- Supply dummy entry at start of length array - - Aggr_Length (0) := Make_Artyp_Literal (0); - - -- Go through operands setting up the above arrays - - J := 1; - while J <= N loop - Opnd := Remove_Head (Opnds); - Opnd_Typ := Etype (Opnd); - - -- The parent got messed up when we put the operands in a list, - -- so now put back the proper parent for the saved operand, that - -- is to say the concatenation node, to make sure that each operand - -- is seen as a subexpression, e.g. if actions must be inserted. - - Set_Parent (Opnd, Cnode); - - -- Set will be True when we have setup one entry in the array - - Set := False; - - -- Singleton element (or character literal) case - - if Base_Type (Opnd_Typ) = Ctyp then - NN := NN + 1; - Operands (NN) := Opnd; - Is_Fixed_Length (NN) := True; - Fixed_Length (NN) := Uint_1; - Result_May_Be_Null := False; - - -- Set low bound of operand (no need to set Last_Opnd_High_Bound - -- since we know that the result cannot be null). - - Opnd_Low_Bound (NN) := - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Istyp, Loc), - Attribute_Name => Name_First); - - Set := True; - - -- String literal case (can only occur for strings of course) - - elsif Nkind (Opnd) = N_String_Literal then - Len := String_Literal_Length (Opnd_Typ); - - if Len /= 0 then - Result_May_Be_Null := False; - end if; - - -- Capture last operand low and high bound if result could be null - - if J = N and then Result_May_Be_Null then - Last_Opnd_Low_Bound := - New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); - - Last_Opnd_High_Bound := - Make_Op_Subtract (Loc, - Left_Opnd => - New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)), - Right_Opnd => Make_Integer_Literal (Loc, 1)); - end if; - - -- Skip null string literal - - if J < N and then Len = 0 then - goto Continue; - end if; - - NN := NN + 1; - Operands (NN) := Opnd; - Is_Fixed_Length (NN) := True; - - -- Set length and bounds - - Fixed_Length (NN) := Len; - - Opnd_Low_Bound (NN) := - New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); - - Set := True; - - -- All other cases - - else - -- Check constrained case with known bounds - - if Is_Constrained (Opnd_Typ) then - declare - Index : constant Node_Id := First_Index (Opnd_Typ); - Indx_Typ : constant Entity_Id := Etype (Index); - Lo : constant Node_Id := Type_Low_Bound (Indx_Typ); - Hi : constant Node_Id := Type_High_Bound (Indx_Typ); - - begin - -- Fixed length constrained array type with known at compile - -- time bounds is last case of fixed length operand. - - if Compile_Time_Known_Value (Lo) - and then - Compile_Time_Known_Value (Hi) - then - declare - Loval : constant Uint := Expr_Value (Lo); - Hival : constant Uint := Expr_Value (Hi); - Len : constant Uint := - UI_Max (Hival - Loval + 1, Uint_0); - - begin - if Len > 0 then - Result_May_Be_Null := False; - end if; - - -- Capture last operand bounds if result could be null - - if J = N and then Result_May_Be_Null then - Last_Opnd_Low_Bound := - Convert_To (Ityp, - Make_Integer_Literal (Loc, Expr_Value (Lo))); - - Last_Opnd_High_Bound := - Convert_To (Ityp, - Make_Integer_Literal (Loc, Expr_Value (Hi))); - end if; - - -- Exclude null length case unless last operand - - if J < N and then Len = 0 then - goto Continue; - end if; - - NN := NN + 1; - Operands (NN) := Opnd; - Is_Fixed_Length (NN) := True; - Fixed_Length (NN) := Len; - - Opnd_Low_Bound (NN) := - To_Ityp - (Make_Integer_Literal (Loc, Expr_Value (Lo))); - Set := True; - end; - end if; - end; - end if; - - -- All cases where the length is not known at compile time, or the - -- special case of an operand which is known to be null but has a - -- lower bound other than 1 or is other than a string type. - - if not Set then - NN := NN + 1; - - -- Capture operand bounds - - Opnd_Low_Bound (NN) := - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr (Opnd, Name_Req => True), - Attribute_Name => Name_First); - Set_Parent (Opnd_Low_Bound (NN), Opnd); - - -- Capture last operand bounds if result could be null - - if J = N and Result_May_Be_Null then - Last_Opnd_Low_Bound := - Convert_To (Ityp, - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr (Opnd, Name_Req => True), - Attribute_Name => Name_First)); - Set_Parent (Last_Opnd_Low_Bound, Opnd); - - Last_Opnd_High_Bound := - Convert_To (Ityp, - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr (Opnd, Name_Req => True), - Attribute_Name => Name_Last)); - Set_Parent (Last_Opnd_High_Bound, Opnd); - end if; - - -- Capture length of operand in entity - - Operands (NN) := Opnd; - Is_Fixed_Length (NN) := False; - - Var_Length (NN) := Make_Temporary (Loc, 'L'); - - Append_To (Actions, - Make_Object_Declaration (Loc, - Defining_Identifier => Var_Length (NN), - Constant_Present => True, - Object_Definition => New_Occurrence_Of (Artyp, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr (Opnd, Name_Req => True), - Attribute_Name => Name_Length))); - end if; - end if; - - -- Set next entry in aggregate length array - - -- For first entry, make either integer literal for fixed length - -- or a reference to the saved length for variable length. - - if NN = 1 then - if Is_Fixed_Length (1) then - Aggr_Length (1) := Make_Integer_Literal (Loc, Fixed_Length (1)); - else - Aggr_Length (1) := New_Reference_To (Var_Length (1), Loc); - end if; - - -- If entry is fixed length and only fixed lengths so far, make - -- appropriate new integer literal adding new length. - - elsif Is_Fixed_Length (NN) - and then Nkind (Aggr_Length (NN - 1)) = N_Integer_Literal - then - Aggr_Length (NN) := - Make_Integer_Literal (Loc, - Intval => Fixed_Length (NN) + Intval (Aggr_Length (NN - 1))); - - -- All other cases, construct an addition node for the length and - -- create an entity initialized to this length. - - else - Ent := Make_Temporary (Loc, 'L'); - - if Is_Fixed_Length (NN) then - Clen := Make_Integer_Literal (Loc, Fixed_Length (NN)); - else - Clen := New_Reference_To (Var_Length (NN), Loc); - end if; - - Append_To (Actions, - Make_Object_Declaration (Loc, - Defining_Identifier => Ent, - Constant_Present => True, - Object_Definition => New_Occurrence_Of (Artyp, Loc), - Expression => - Make_Op_Add (Loc, - Left_Opnd => New_Copy (Aggr_Length (NN - 1)), - Right_Opnd => Clen))); - - Aggr_Length (NN) := Make_Identifier (Loc, Chars => Chars (Ent)); - end if; - - <<Continue>> - J := J + 1; - end loop; - - -- If we have only skipped null operands, return the last operand - - if NN = 0 then - Result := Opnd; - goto Done; - end if; - - -- If we have only one non-null operand, return it and we are done. - -- There is one case in which this cannot be done, and that is when - -- the sole operand is of the element type, in which case it must be - -- converted to an array, and the easiest way of doing that is to go - -- through the normal general circuit. - - if NN = 1 - and then Base_Type (Etype (Operands (1))) /= Ctyp - then - Result := Operands (1); - goto Done; - end if; - - -- Cases where we have a real concatenation - - -- Next step is to find the low bound for the result array that we - -- will allocate. The rules for this are in (RM 4.5.6(5-7)). - - -- If the ultimate ancestor of the index subtype is a constrained array - -- definition, then the lower bound is that of the index subtype as - -- specified by (RM 4.5.3(6)). - - -- The right test here is to go to the root type, and then the ultimate - -- ancestor is the first subtype of this root type. - - if Is_Constrained (First_Subtype (Root_Type (Atyp))) then - Low_Bound := - Make_Attribute_Reference (Loc, - Prefix => - New_Occurrence_Of (First_Subtype (Root_Type (Atyp)), Loc), - Attribute_Name => Name_First); - - -- If the first operand in the list has known length we know that - -- the lower bound of the result is the lower bound of this operand. - - elsif Is_Fixed_Length (1) then - Low_Bound := Opnd_Low_Bound (1); - - -- OK, we don't know the lower bound, we have to build a horrible - -- if expression node of the form - - -- if Cond1'Length /= 0 then - -- Opnd1 low bound - -- else - -- if Opnd2'Length /= 0 then - -- Opnd2 low bound - -- else - -- ... - - -- The nesting ends either when we hit an operand whose length is known - -- at compile time, or on reaching the last operand, whose low bound we - -- take unconditionally whether or not it is null. It's easiest to do - -- this with a recursive procedure: - - else - declare - function Get_Known_Bound (J : Nat) return Node_Id; - -- Returns the lower bound determined by operands J .. NN - - --------------------- - -- Get_Known_Bound -- - --------------------- - - function Get_Known_Bound (J : Nat) return Node_Id is - begin - if Is_Fixed_Length (J) or else J = NN then - return New_Copy (Opnd_Low_Bound (J)); - - else - return - Make_If_Expression (Loc, - Expressions => New_List ( - - Make_Op_Ne (Loc, - Left_Opnd => New_Reference_To (Var_Length (J), Loc), - Right_Opnd => Make_Integer_Literal (Loc, 0)), - - New_Copy (Opnd_Low_Bound (J)), - Get_Known_Bound (J + 1))); - end if; - end Get_Known_Bound; - - begin - Ent := Make_Temporary (Loc, 'L'); - - Append_To (Actions, - Make_Object_Declaration (Loc, - Defining_Identifier => Ent, - Constant_Present => True, - Object_Definition => New_Occurrence_Of (Ityp, Loc), - Expression => Get_Known_Bound (1))); - - Low_Bound := New_Reference_To (Ent, Loc); - end; - end if; - - -- Now we can safely compute the upper bound, normally - -- Low_Bound + Length - 1. - - High_Bound := - To_Ityp ( - Make_Op_Add (Loc, - Left_Opnd => To_Artyp (New_Copy (Low_Bound)), - Right_Opnd => - Make_Op_Subtract (Loc, - Left_Opnd => New_Copy (Aggr_Length (NN)), - Right_Opnd => Make_Artyp_Literal (1)))); - - -- Note that calculation of the high bound may cause overflow in some - -- very weird cases, so in the general case we need an overflow check on - -- the high bound. We can avoid this for the common case of string types - -- and other types whose index is Positive, since we chose a wider range - -- for the arithmetic type. - - if Istyp /= Standard_Positive then - Activate_Overflow_Check (High_Bound); - end if; - - -- Handle the exceptional case where the result is null, in which case - -- case the bounds come from the last operand (so that we get the proper - -- bounds if the last operand is super-flat). - - if Result_May_Be_Null then - Low_Bound := - Make_If_Expression (Loc, - Expressions => New_List ( - Make_Op_Eq (Loc, - Left_Opnd => New_Copy (Aggr_Length (NN)), - Right_Opnd => Make_Artyp_Literal (0)), - Last_Opnd_Low_Bound, - Low_Bound)); - - High_Bound := - Make_If_Expression (Loc, - Expressions => New_List ( - Make_Op_Eq (Loc, - Left_Opnd => New_Copy (Aggr_Length (NN)), - Right_Opnd => Make_Artyp_Literal (0)), - Last_Opnd_High_Bound, - High_Bound)); - end if; - - -- Here is where we insert the saved up actions - - Insert_Actions (Cnode, Actions, Suppress => All_Checks); - - -- Now we construct an array object with appropriate bounds. We mark - -- the target as internal to prevent useless initialization when - -- Initialize_Scalars is enabled. Also since this is the actual result - -- entity, we make sure we have debug information for the result. - - Ent := Make_Temporary (Loc, 'S'); - Set_Is_Internal (Ent); - Set_Needs_Debug_Info (Ent); - - -- If the bound is statically known to be out of range, we do not want - -- to abort, we want a warning and a runtime constraint error. Note that - -- we have arranged that the result will not be treated as a static - -- constant, so we won't get an illegality during this insertion. - - Insert_Action (Cnode, - Make_Object_Declaration (Loc, - Defining_Identifier => Ent, - Object_Definition => - Make_Subtype_Indication (Loc, - Subtype_Mark => New_Occurrence_Of (Atyp, Loc), - Constraint => - Make_Index_Or_Discriminant_Constraint (Loc, - Constraints => New_List ( - Make_Range (Loc, - Low_Bound => Low_Bound, - High_Bound => High_Bound))))), - Suppress => All_Checks); - - -- If the result of the concatenation appears as the initializing - -- expression of an object declaration, we can just rename the - -- result, rather than copying it. - - Set_OK_To_Rename (Ent); - - -- Catch the static out of range case now - - if Raises_Constraint_Error (High_Bound) then - raise Concatenation_Error; - end if; - - -- Now we will generate the assignments to do the actual concatenation - - -- There is one case in which we will not do this, namely when all the - -- following conditions are met: - - -- The result type is Standard.String - - -- There are nine or fewer retained (non-null) operands - - -- The optimization level is -O0 - - -- The corresponding System.Concat_n.Str_Concat_n routine is - -- available in the run time. - - -- The debug flag gnatd.c is not set - - -- If all these conditions are met then we generate a call to the - -- relevant concatenation routine. The purpose of this is to avoid - -- undesirable code bloat at -O0. - - if Atyp = Standard_String - and then NN in 2 .. 9 - and then (Opt.Optimization_Level = 0 or else Debug_Flag_Dot_CC) - and then not Debug_Flag_Dot_C - then - declare - RR : constant array (Nat range 2 .. 9) of RE_Id := - (RE_Str_Concat_2, - RE_Str_Concat_3, - RE_Str_Concat_4, - RE_Str_Concat_5, - RE_Str_Concat_6, - RE_Str_Concat_7, - RE_Str_Concat_8, - RE_Str_Concat_9); - - begin - if RTE_Available (RR (NN)) then - declare - Opnds : constant List_Id := - New_List (New_Occurrence_Of (Ent, Loc)); - - begin - for J in 1 .. NN loop - if Is_List_Member (Operands (J)) then - Remove (Operands (J)); - end if; - - if Base_Type (Etype (Operands (J))) = Ctyp then - Append_To (Opnds, - Make_Aggregate (Loc, - Component_Associations => New_List ( - Make_Component_Association (Loc, - Choices => New_List ( - Make_Integer_Literal (Loc, 1)), - Expression => Operands (J))))); - - else - Append_To (Opnds, Operands (J)); - end if; - end loop; - - Insert_Action (Cnode, - Make_Procedure_Call_Statement (Loc, - Name => New_Reference_To (RTE (RR (NN)), Loc), - Parameter_Associations => Opnds)); - - Result := New_Reference_To (Ent, Loc); - goto Done; - end; - end if; - end; - end if; - - -- Not special case so generate the assignments - - Known_Non_Null_Operand_Seen := False; - - for J in 1 .. NN loop - declare - Lo : constant Node_Id := - Make_Op_Add (Loc, - Left_Opnd => To_Artyp (New_Copy (Low_Bound)), - Right_Opnd => Aggr_Length (J - 1)); - - Hi : constant Node_Id := - Make_Op_Add (Loc, - Left_Opnd => To_Artyp (New_Copy (Low_Bound)), - Right_Opnd => - Make_Op_Subtract (Loc, - Left_Opnd => Aggr_Length (J), - Right_Opnd => Make_Artyp_Literal (1))); - - begin - -- Singleton case, simple assignment - - if Base_Type (Etype (Operands (J))) = Ctyp then - Known_Non_Null_Operand_Seen := True; - Insert_Action (Cnode, - Make_Assignment_Statement (Loc, - Name => - Make_Indexed_Component (Loc, - Prefix => New_Occurrence_Of (Ent, Loc), - Expressions => New_List (To_Ityp (Lo))), - Expression => Operands (J)), - Suppress => All_Checks); - - -- Array case, slice assignment, skipped when argument is fixed - -- length and known to be null. - - elsif (not Is_Fixed_Length (J)) or else (Fixed_Length (J) > 0) then - declare - Assign : Node_Id := - Make_Assignment_Statement (Loc, - Name => - Make_Slice (Loc, - Prefix => - New_Occurrence_Of (Ent, Loc), - Discrete_Range => - Make_Range (Loc, - Low_Bound => To_Ityp (Lo), - High_Bound => To_Ityp (Hi))), - Expression => Operands (J)); - begin - if Is_Fixed_Length (J) then - Known_Non_Null_Operand_Seen := True; - - elsif not Known_Non_Null_Operand_Seen then - - -- Here if operand length is not statically known and no - -- operand known to be non-null has been processed yet. - -- If operand length is 0, we do not need to perform the - -- assignment, and we must avoid the evaluation of the - -- high bound of the slice, since it may underflow if the - -- low bound is Ityp'First. - - Assign := - Make_Implicit_If_Statement (Cnode, - Condition => - Make_Op_Ne (Loc, - Left_Opnd => - New_Occurrence_Of (Var_Length (J), Loc), - Right_Opnd => Make_Integer_Literal (Loc, 0)), - Then_Statements => New_List (Assign)); - end if; - - Insert_Action (Cnode, Assign, Suppress => All_Checks); - end; - end if; - end; - end loop; - - -- Finally we build the result, which is a reference to the array object - - Result := New_Reference_To (Ent, Loc); - - <<Done>> - Rewrite (Cnode, Result); - Analyze_And_Resolve (Cnode, Atyp); - - exception - when Concatenation_Error => - - -- Kill warning generated for the declaration of the static out of - -- range high bound, and instead generate a Constraint_Error with - -- an appropriate specific message. - - Kill_Dead_Code (Declaration_Node (Entity (High_Bound))); - Apply_Compile_Time_Constraint_Error - (N => Cnode, - Msg => "concatenation result upper bound out of range??", - Reason => CE_Range_Check_Failed); - end Expand_Concatenate; - - --------------------------------------------------- - -- Expand_Membership_Minimize_Eliminate_Overflow -- - --------------------------------------------------- - - procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id) is - pragma Assert (Nkind (N) = N_In); - -- Despite the name, this routine applies only to N_In, not to - -- N_Not_In. The latter is always rewritten as not (X in Y). - - Result_Type : constant Entity_Id := Etype (N); - -- Capture result type, may be a derived boolean type - - Loc : constant Source_Ptr := Sloc (N); - Lop : constant Node_Id := Left_Opnd (N); - Rop : constant Node_Id := Right_Opnd (N); - - -- Note: there are many referencs to Etype (Lop) and Etype (Rop). It - -- is thus tempting to capture these values, but due to the rewrites - -- that occur as a result of overflow checking, these values change - -- as we go along, and it is safe just to always use Etype explicitly. - - Restype : constant Entity_Id := Etype (N); - -- Save result type - - Lo, Hi : Uint; - -- Bounds in Minimize calls, not used currently - - LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); - -- Entity for Long_Long_Integer'Base (Standard should export this???) - - begin - Minimize_Eliminate_Overflows (Lop, Lo, Hi, Top_Level => False); - - -- If right operand is a subtype name, and the subtype name has no - -- predicate, then we can just replace the right operand with an - -- explicit range T'First .. T'Last, and use the explicit range code. - - if Nkind (Rop) /= N_Range - and then No (Predicate_Function (Etype (Rop))) - then - declare - Rtyp : constant Entity_Id := Etype (Rop); - begin - Rewrite (Rop, - Make_Range (Loc, - Low_Bound => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => New_Reference_To (Rtyp, Loc)), - High_Bound => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => New_Reference_To (Rtyp, Loc)))); - Analyze_And_Resolve (Rop, Rtyp, Suppress => All_Checks); - end; - end if; - - -- Here for the explicit range case. Note that the bounds of the range - -- have not been processed for minimized or eliminated checks. - - if Nkind (Rop) = N_Range then - Minimize_Eliminate_Overflows - (Low_Bound (Rop), Lo, Hi, Top_Level => False); - Minimize_Eliminate_Overflows - (High_Bound (Rop), Lo, Hi, Top_Level => False); - - -- We have A in B .. C, treated as A >= B and then A <= C - - -- Bignum case - - if Is_RTE (Etype (Lop), RE_Bignum) - or else Is_RTE (Etype (Low_Bound (Rop)), RE_Bignum) - or else Is_RTE (Etype (High_Bound (Rop)), RE_Bignum) - then - declare - Blk : constant Node_Id := Make_Bignum_Block (Loc); - Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); - L : constant Entity_Id := - Make_Defining_Identifier (Loc, Name_uL); - Lopnd : constant Node_Id := Convert_To_Bignum (Lop); - Lbound : constant Node_Id := - Convert_To_Bignum (Low_Bound (Rop)); - Hbound : constant Node_Id := - Convert_To_Bignum (High_Bound (Rop)); - - -- Now we rewrite the membership test node to look like - - -- do - -- Bnn : Result_Type; - -- declare - -- M : Mark_Id := SS_Mark; - -- L : Bignum := Lopnd; - -- begin - -- Bnn := Big_GE (L, Lbound) and then Big_LE (L, Hbound) - -- SS_Release (M); - -- end; - -- in - -- Bnn - -- end - - begin - -- Insert declaration of L into declarations of bignum block - - Insert_After - (Last (Declarations (Blk)), - Make_Object_Declaration (Loc, - Defining_Identifier => L, - Object_Definition => - New_Occurrence_Of (RTE (RE_Bignum), Loc), - Expression => Lopnd)); - - -- Insert assignment to Bnn into expressions of bignum block - - Insert_Before - (First (Statements (Handled_Statement_Sequence (Blk))), - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Bnn, Loc), - Expression => - Make_And_Then (Loc, - Left_Opnd => - Make_Function_Call (Loc, - Name => - New_Occurrence_Of (RTE (RE_Big_GE), Loc), - Parameter_Associations => New_List ( - New_Occurrence_Of (L, Loc), - Lbound)), - Right_Opnd => - Make_Function_Call (Loc, - Name => - New_Occurrence_Of (RTE (RE_Big_LE), Loc), - Parameter_Associations => New_List ( - New_Occurrence_Of (L, Loc), - Hbound))))); - - -- Now rewrite the node - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Actions => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => Bnn, - Object_Definition => - New_Occurrence_Of (Result_Type, Loc)), - Blk), - Expression => New_Occurrence_Of (Bnn, Loc))); - Analyze_And_Resolve (N, Result_Type); - return; - end; - - -- Here if no bignums around - - else - -- Case where types are all the same - - if Base_Type (Etype (Lop)) = Base_Type (Etype (Low_Bound (Rop))) - and then - Base_Type (Etype (Lop)) = Base_Type (Etype (High_Bound (Rop))) - then - null; - - -- If types are not all the same, it means that we have rewritten - -- at least one of them to be of type Long_Long_Integer, and we - -- will convert the other operands to Long_Long_Integer. - - else - Convert_To_And_Rewrite (LLIB, Lop); - Set_Analyzed (Lop, False); - Analyze_And_Resolve (Lop, LLIB); - - -- For the right operand, avoid unnecessary recursion into - -- this routine, we know that overflow is not possible. - - Convert_To_And_Rewrite (LLIB, Low_Bound (Rop)); - Convert_To_And_Rewrite (LLIB, High_Bound (Rop)); - Set_Analyzed (Rop, False); - Analyze_And_Resolve (Rop, LLIB, Suppress => Overflow_Check); - end if; - - -- Now the three operands are of the same signed integer type, - -- so we can use the normal expansion routine for membership, - -- setting the flag to prevent recursion into this procedure. - - Set_No_Minimize_Eliminate (N); - Expand_N_In (N); - end if; - - -- Right operand is a subtype name and the subtype has a predicate. We - -- have to make sure the predicate is checked, and for that we need to - -- use the standard N_In circuitry with appropriate types. - - else - pragma Assert (Present (Predicate_Function (Etype (Rop)))); - - -- If types are "right", just call Expand_N_In preventing recursion - - if Base_Type (Etype (Lop)) = Base_Type (Etype (Rop)) then - Set_No_Minimize_Eliminate (N); - Expand_N_In (N); - - -- Bignum case - - elsif Is_RTE (Etype (Lop), RE_Bignum) then - - -- For X in T, we want to rewrite our node as - - -- do - -- Bnn : Result_Type; - - -- declare - -- M : Mark_Id := SS_Mark; - -- Lnn : Long_Long_Integer'Base - -- Nnn : Bignum; - - -- begin - -- Nnn := X; - - -- if not Bignum_In_LLI_Range (Nnn) then - -- Bnn := False; - -- else - -- Lnn := From_Bignum (Nnn); - -- Bnn := - -- Lnn in LLIB (T'Base'First) .. LLIB (T'Base'Last) - -- and then T'Base (Lnn) in T; - -- end if; - -- - -- SS_Release (M); - -- end - -- in - -- Bnn - -- end - - -- A bit gruesome, but there doesn't seem to be a simpler way - - declare - Blk : constant Node_Id := Make_Bignum_Block (Loc); - Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); - Lnn : constant Entity_Id := Make_Temporary (Loc, 'L', N); - Nnn : constant Entity_Id := Make_Temporary (Loc, 'N', N); - T : constant Entity_Id := Etype (Rop); - TB : constant Entity_Id := Base_Type (T); - Nin : Node_Id; - - begin - -- Mark the last membership operation to prevent recursion - - Nin := - Make_In (Loc, - Left_Opnd => Convert_To (TB, New_Occurrence_Of (Lnn, Loc)), - Right_Opnd => New_Occurrence_Of (T, Loc)); - Set_No_Minimize_Eliminate (Nin); - - -- Now decorate the block - - Insert_After - (Last (Declarations (Blk)), - Make_Object_Declaration (Loc, - Defining_Identifier => Lnn, - Object_Definition => New_Occurrence_Of (LLIB, Loc))); - - Insert_After - (Last (Declarations (Blk)), - Make_Object_Declaration (Loc, - Defining_Identifier => Nnn, - Object_Definition => - New_Occurrence_Of (RTE (RE_Bignum), Loc))); - - Insert_List_Before - (First (Statements (Handled_Statement_Sequence (Blk))), - New_List ( - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Nnn, Loc), - Expression => Relocate_Node (Lop)), - - Make_If_Statement (Loc, - Condition => - Make_Op_Not (Loc, - Right_Opnd => - Make_Function_Call (Loc, - Name => - New_Occurrence_Of - (RTE (RE_Bignum_In_LLI_Range), Loc), - Parameter_Associations => New_List ( - New_Occurrence_Of (Nnn, Loc)))), - - Then_Statements => New_List ( - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Bnn, Loc), - Expression => - New_Occurrence_Of (Standard_False, Loc))), - - Else_Statements => New_List ( - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Lnn, Loc), - Expression => - Make_Function_Call (Loc, - Name => - New_Occurrence_Of (RTE (RE_From_Bignum), Loc), - Parameter_Associations => New_List ( - New_Occurrence_Of (Nnn, Loc)))), - - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Bnn, Loc), - Expression => - Make_And_Then (Loc, - Left_Opnd => - Make_In (Loc, - Left_Opnd => New_Occurrence_Of (Lnn, Loc), - Right_Opnd => - Make_Range (Loc, - Low_Bound => - Convert_To (LLIB, - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => - New_Occurrence_Of (TB, Loc))), - - High_Bound => - Convert_To (LLIB, - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => - New_Occurrence_Of (TB, Loc))))), - - Right_Opnd => Nin)))))); - - -- Now we can do the rewrite - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Actions => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => Bnn, - Object_Definition => - New_Occurrence_Of (Result_Type, Loc)), - Blk), - Expression => New_Occurrence_Of (Bnn, Loc))); - Analyze_And_Resolve (N, Result_Type); - return; - end; - - -- Not bignum case, but types don't match (this means we rewrote the - -- left operand to be Long_Long_Integer). - - else - pragma Assert (Base_Type (Etype (Lop)) = LLIB); - - -- We rewrite the membership test as (where T is the type with - -- the predicate, i.e. the type of the right operand) - - -- Lop in LLIB (T'Base'First) .. LLIB (T'Base'Last) - -- and then T'Base (Lop) in T - - declare - T : constant Entity_Id := Etype (Rop); - TB : constant Entity_Id := Base_Type (T); - Nin : Node_Id; - - begin - -- The last membership test is marked to prevent recursion - - Nin := - Make_In (Loc, - Left_Opnd => Convert_To (TB, Duplicate_Subexpr (Lop)), - Right_Opnd => New_Occurrence_Of (T, Loc)); - Set_No_Minimize_Eliminate (Nin); - - -- Now do the rewrite - - Rewrite (N, - Make_And_Then (Loc, - Left_Opnd => - Make_In (Loc, - Left_Opnd => Lop, - Right_Opnd => - Make_Range (Loc, - Low_Bound => - Convert_To (LLIB, - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => New_Occurrence_Of (TB, Loc))), - High_Bound => - Convert_To (LLIB, - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => New_Occurrence_Of (TB, Loc))))), - Right_Opnd => Nin)); - Set_Analyzed (N, False); - Analyze_And_Resolve (N, Restype); - end; - end if; - end if; - end Expand_Membership_Minimize_Eliminate_Overflow; - - ------------------------ - -- Expand_N_Allocator -- - ------------------------ - - procedure Expand_N_Allocator (N : Node_Id) is - PtrT : constant Entity_Id := Etype (N); - Dtyp : constant Entity_Id := Available_View (Designated_Type (PtrT)); - Etyp : constant Entity_Id := Etype (Expression (N)); - Loc : constant Source_Ptr := Sloc (N); - Desig : Entity_Id; - Nod : Node_Id; - Pool : Entity_Id; - Temp : Entity_Id; - - procedure Rewrite_Coextension (N : Node_Id); - -- Static coextensions have the same lifetime as the entity they - -- constrain. Such occurrences can be rewritten as aliased objects - -- and their unrestricted access used instead of the coextension. - - function Size_In_Storage_Elements (E : Entity_Id) return Node_Id; - -- Given a constrained array type E, returns a node representing the - -- code to compute the size in storage elements for the given type. - -- This is done without using the attribute (which malfunctions for - -- large sizes ???) - - ------------------------- - -- Rewrite_Coextension -- - ------------------------- - - procedure Rewrite_Coextension (N : Node_Id) is - Temp_Id : constant Node_Id := Make_Temporary (Loc, 'C'); - Temp_Decl : Node_Id; - - begin - -- Generate: - -- Cnn : aliased Etyp; - - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp_Id, - Aliased_Present => True, - Object_Definition => New_Occurrence_Of (Etyp, Loc)); - - if Nkind (Expression (N)) = N_Qualified_Expression then - Set_Expression (Temp_Decl, Expression (Expression (N))); - end if; - - Insert_Action (N, Temp_Decl); - Rewrite (N, - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Temp_Id, Loc), - Attribute_Name => Name_Unrestricted_Access)); - - Analyze_And_Resolve (N, PtrT); - end Rewrite_Coextension; - - ------------------------------ - -- Size_In_Storage_Elements -- - ------------------------------ - - function Size_In_Storage_Elements (E : Entity_Id) return Node_Id is - begin - -- Logically this just returns E'Max_Size_In_Storage_Elements. - -- However, the reason for the existence of this function is - -- to construct a test for sizes too large, which means near the - -- 32-bit limit on a 32-bit machine, and precisely the trouble - -- is that we get overflows when sizes are greater than 2**31. - - -- So what we end up doing for array types is to use the expression: - - -- number-of-elements * component_type'Max_Size_In_Storage_Elements - - -- which avoids this problem. All this is a bit bogus, but it does - -- mean we catch common cases of trying to allocate arrays that - -- are too large, and which in the absence of a check results in - -- undetected chaos ??? - - declare - Len : Node_Id; - Res : Node_Id; - - begin - for J in 1 .. Number_Dimensions (E) loop - Len := - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (E, Loc), - Attribute_Name => Name_Length, - Expressions => New_List (Make_Integer_Literal (Loc, J))); - - if J = 1 then - Res := Len; - - else - Res := - Make_Op_Multiply (Loc, - Left_Opnd => Res, - Right_Opnd => Len); - end if; - end loop; - - return - Make_Op_Multiply (Loc, - Left_Opnd => Len, - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Component_Type (E), Loc), - Attribute_Name => Name_Max_Size_In_Storage_Elements)); - end; - end Size_In_Storage_Elements; - - -- Start of processing for Expand_N_Allocator - - begin - -- RM E.2.3(22). We enforce that the expected type of an allocator - -- shall not be a remote access-to-class-wide-limited-private type - - -- Why is this being done at expansion time, seems clearly wrong ??? - - Validate_Remote_Access_To_Class_Wide_Type (N); - - -- Processing for anonymous access-to-controlled types. These access - -- types receive a special finalization master which appears in the - -- declarations of the enclosing semantic unit. This expansion is done - -- now to ensure that any additional types generated by this routine or - -- Expand_Allocator_Expression inherit the proper type attributes. - - if (Ekind (PtrT) = E_Anonymous_Access_Type - or else - (Is_Itype (PtrT) and then No (Finalization_Master (PtrT)))) - and then Needs_Finalization (Dtyp) - then - -- Anonymous access-to-controlled types allocate on the global pool. - -- Do not set this attribute on .NET/JVM since those targets do not - -- support pools. - - if No (Associated_Storage_Pool (PtrT)) and then VM_Target = No_VM then - Set_Associated_Storage_Pool - (PtrT, Get_Global_Pool_For_Access_Type (PtrT)); - end if; - - -- The finalization master must be inserted and analyzed as part of - -- the current semantic unit. This form of expansion is not carried - -- out in Alfa mode because it is useless. Note that the master is - -- updated when analysis changes current units. - - if not Alfa_Mode then - Set_Finalization_Master (PtrT, Current_Anonymous_Master); - end if; - end if; - - -- Set the storage pool and find the appropriate version of Allocate to - -- call. Do not overwrite the storage pool if it is already set, which - -- can happen for build-in-place function returns (see - -- Exp_Ch4.Expand_N_Extended_Return_Statement). - - if No (Storage_Pool (N)) then - Pool := Associated_Storage_Pool (Root_Type (PtrT)); - - if Present (Pool) then - Set_Storage_Pool (N, Pool); - - if Is_RTE (Pool, RE_SS_Pool) then - if VM_Target = No_VM then - Set_Procedure_To_Call (N, RTE (RE_SS_Allocate)); - end if; - - -- In the case of an allocator for a simple storage pool, locate - -- and save a reference to the pool type's Allocate routine. - - elsif Present (Get_Rep_Pragma - (Etype (Pool), Name_Simple_Storage_Pool_Type)) - then - declare - Pool_Type : constant Entity_Id := Base_Type (Etype (Pool)); - Alloc_Op : Entity_Id; - begin - Alloc_Op := Get_Name_Entity_Id (Name_Allocate); - while Present (Alloc_Op) loop - if Scope (Alloc_Op) = Scope (Pool_Type) - and then Present (First_Formal (Alloc_Op)) - and then Etype (First_Formal (Alloc_Op)) = Pool_Type - then - Set_Procedure_To_Call (N, Alloc_Op); - exit; - else - Alloc_Op := Homonym (Alloc_Op); - end if; - end loop; - end; - - elsif Is_Class_Wide_Type (Etype (Pool)) then - Set_Procedure_To_Call (N, RTE (RE_Allocate_Any)); - - else - Set_Procedure_To_Call (N, - Find_Prim_Op (Etype (Pool), Name_Allocate)); - end if; - end if; - end if; - - -- Under certain circumstances we can replace an allocator by an access - -- to statically allocated storage. The conditions, as noted in AARM - -- 3.10 (10c) are as follows: - - -- Size and initial value is known at compile time - -- Access type is access-to-constant - - -- The allocator is not part of a constraint on a record component, - -- because in that case the inserted actions are delayed until the - -- record declaration is fully analyzed, which is too late for the - -- analysis of the rewritten allocator. - - if Is_Access_Constant (PtrT) - and then Nkind (Expression (N)) = N_Qualified_Expression - and then Compile_Time_Known_Value (Expression (Expression (N))) - and then Size_Known_At_Compile_Time - (Etype (Expression (Expression (N)))) - and then not Is_Record_Type (Current_Scope) - then - -- Here we can do the optimization. For the allocator - - -- new x'(y) - - -- We insert an object declaration - - -- Tnn : aliased x := y; - - -- and replace the allocator by Tnn'Unrestricted_Access. Tnn is - -- marked as requiring static allocation. - - Temp := Make_Temporary (Loc, 'T', Expression (Expression (N))); - Desig := Subtype_Mark (Expression (N)); - - -- If context is constrained, use constrained subtype directly, - -- so that the constant is not labelled as having a nominally - -- unconstrained subtype. - - if Entity (Desig) = Base_Type (Dtyp) then - Desig := New_Occurrence_Of (Dtyp, Loc); - end if; - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Aliased_Present => True, - Constant_Present => Is_Access_Constant (PtrT), - Object_Definition => Desig, - Expression => Expression (Expression (N)))); - - Rewrite (N, - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Temp, Loc), - Attribute_Name => Name_Unrestricted_Access)); - - Analyze_And_Resolve (N, PtrT); - - -- We set the variable as statically allocated, since we don't want - -- it going on the stack of the current procedure! - - Set_Is_Statically_Allocated (Temp); - return; - end if; - - -- Same if the allocator is an access discriminant for a local object: - -- instead of an allocator we create a local value and constrain the - -- enclosing object with the corresponding access attribute. - - if Is_Static_Coextension (N) then - Rewrite_Coextension (N); - return; - end if; - - -- Check for size too large, we do this because the back end misses - -- proper checks here and can generate rubbish allocation calls when - -- we are near the limit. We only do this for the 32-bit address case - -- since that is from a practical point of view where we see a problem. - - if System_Address_Size = 32 - and then not Storage_Checks_Suppressed (PtrT) - and then not Storage_Checks_Suppressed (Dtyp) - and then not Storage_Checks_Suppressed (Etyp) - then - -- The check we want to generate should look like - - -- if Etyp'Max_Size_In_Storage_Elements > 3.5 gigabytes then - -- raise Storage_Error; - -- end if; - - -- where 3.5 gigabytes is a constant large enough to accommodate any - -- reasonable request for. But we can't do it this way because at - -- least at the moment we don't compute this attribute right, and - -- can silently give wrong results when the result gets large. Since - -- this is all about large results, that's bad, so instead we only - -- apply the check for constrained arrays, and manually compute the - -- value of the attribute ??? - - if Is_Array_Type (Etyp) and then Is_Constrained (Etyp) then - Insert_Action (N, - Make_Raise_Storage_Error (Loc, - Condition => - Make_Op_Gt (Loc, - Left_Opnd => Size_In_Storage_Elements (Etyp), - Right_Opnd => - Make_Integer_Literal (Loc, Uint_7 * (Uint_2 ** 29))), - Reason => SE_Object_Too_Large)); - end if; - end if; - - -- Handle case of qualified expression (other than optimization above) - -- First apply constraint checks, because the bounds or discriminants - -- in the aggregate might not match the subtype mark in the allocator. - - if Nkind (Expression (N)) = N_Qualified_Expression then - Apply_Constraint_Check - (Expression (Expression (N)), Etype (Expression (N))); - - Expand_Allocator_Expression (N); - return; - end if; - - -- If the allocator is for a type which requires initialization, and - -- there is no initial value (i.e. operand is a subtype indication - -- rather than a qualified expression), then we must generate a call to - -- the initialization routine using an expressions action node: - - -- [Pnnn : constant ptr_T := new (T); Init (Pnnn.all,...); Pnnn] - - -- Here ptr_T is the pointer type for the allocator, and T is the - -- subtype of the allocator. A special case arises if the designated - -- type of the access type is a task or contains tasks. In this case - -- the call to Init (Temp.all ...) is replaced by code that ensures - -- that tasks get activated (see Exp_Ch9.Build_Task_Allocate_Block - -- for details). In addition, if the type T is a task T, then the - -- first argument to Init must be converted to the task record type. - - declare - T : constant Entity_Id := Entity (Expression (N)); - Args : List_Id; - Decls : List_Id; - Decl : Node_Id; - Discr : Elmt_Id; - Init : Entity_Id; - Init_Arg1 : Node_Id; - Temp_Decl : Node_Id; - Temp_Type : Entity_Id; - - begin - if No_Initialization (N) then - - -- Even though this might be a simple allocation, create a custom - -- Allocate if the context requires it. Since .NET/JVM compilers - -- do not support pools, this step is skipped. - - if VM_Target = No_VM - and then Present (Finalization_Master (PtrT)) - then - Build_Allocate_Deallocate_Proc - (N => N, - Is_Allocate => True); - end if; - - -- Case of no initialization procedure present - - elsif not Has_Non_Null_Base_Init_Proc (T) then - - -- Case of simple initialization required - - if Needs_Simple_Initialization (T) then - Check_Restriction (No_Default_Initialization, N); - Rewrite (Expression (N), - Make_Qualified_Expression (Loc, - Subtype_Mark => New_Occurrence_Of (T, Loc), - Expression => Get_Simple_Init_Val (T, N))); - - Analyze_And_Resolve (Expression (Expression (N)), T); - Analyze_And_Resolve (Expression (N), T); - Set_Paren_Count (Expression (Expression (N)), 1); - Expand_N_Allocator (N); - - -- No initialization required - - else - null; - end if; - - -- Case of initialization procedure present, must be called - - else - Check_Restriction (No_Default_Initialization, N); - - if not Restriction_Active (No_Default_Initialization) then - Init := Base_Init_Proc (T); - Nod := N; - Temp := Make_Temporary (Loc, 'P'); - - -- Construct argument list for the initialization routine call - - Init_Arg1 := - Make_Explicit_Dereference (Loc, - Prefix => - New_Reference_To (Temp, Loc)); - - Set_Assignment_OK (Init_Arg1); - Temp_Type := PtrT; - - -- The initialization procedure expects a specific type. if the - -- context is access to class wide, indicate that the object - -- being allocated has the right specific type. - - if Is_Class_Wide_Type (Dtyp) then - Init_Arg1 := Unchecked_Convert_To (T, Init_Arg1); - end if; - - -- If designated type is a concurrent type or if it is private - -- type whose definition is a concurrent type, the first - -- argument in the Init routine has to be unchecked conversion - -- to the corresponding record type. If the designated type is - -- a derived type, also convert the argument to its root type. - - if Is_Concurrent_Type (T) then - Init_Arg1 := - Unchecked_Convert_To ( - Corresponding_Record_Type (T), Init_Arg1); - - elsif Is_Private_Type (T) - and then Present (Full_View (T)) - and then Is_Concurrent_Type (Full_View (T)) - then - Init_Arg1 := - Unchecked_Convert_To - (Corresponding_Record_Type (Full_View (T)), Init_Arg1); - - elsif Etype (First_Formal (Init)) /= Base_Type (T) then - declare - Ftyp : constant Entity_Id := Etype (First_Formal (Init)); - - begin - Init_Arg1 := OK_Convert_To (Etype (Ftyp), Init_Arg1); - Set_Etype (Init_Arg1, Ftyp); - end; - end if; - - Args := New_List (Init_Arg1); - - -- For the task case, pass the Master_Id of the access type as - -- the value of the _Master parameter, and _Chain as the value - -- of the _Chain parameter (_Chain will be defined as part of - -- the generated code for the allocator). - - -- In Ada 2005, the context may be a function that returns an - -- anonymous access type. In that case the Master_Id has been - -- created when expanding the function declaration. - - if Has_Task (T) then - if No (Master_Id (Base_Type (PtrT))) then - - -- The designated type was an incomplete type, and the - -- access type did not get expanded. Salvage it now. - - if not Restriction_Active (No_Task_Hierarchy) then - pragma Assert (Present (Parent (Base_Type (PtrT)))); - Expand_N_Full_Type_Declaration - (Parent (Base_Type (PtrT))); - end if; - end if; - - -- If the context of the allocator is a declaration or an - -- assignment, we can generate a meaningful image for it, - -- even though subsequent assignments might remove the - -- connection between task and entity. We build this image - -- when the left-hand side is a simple variable, a simple - -- indexed assignment or a simple selected component. - - if Nkind (Parent (N)) = N_Assignment_Statement then - declare - Nam : constant Node_Id := Name (Parent (N)); - - begin - if Is_Entity_Name (Nam) then - Decls := - Build_Task_Image_Decls - (Loc, - New_Occurrence_Of - (Entity (Nam), Sloc (Nam)), T); - - elsif Nkind_In (Nam, N_Indexed_Component, - N_Selected_Component) - and then Is_Entity_Name (Prefix (Nam)) - then - Decls := - Build_Task_Image_Decls - (Loc, Nam, Etype (Prefix (Nam))); - else - Decls := Build_Task_Image_Decls (Loc, T, T); - end if; - end; - - elsif Nkind (Parent (N)) = N_Object_Declaration then - Decls := - Build_Task_Image_Decls - (Loc, Defining_Identifier (Parent (N)), T); - - else - Decls := Build_Task_Image_Decls (Loc, T, T); - end if; - - if Restriction_Active (No_Task_Hierarchy) then - Append_To (Args, - New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc)); - else - Append_To (Args, - New_Reference_To - (Master_Id (Base_Type (Root_Type (PtrT))), Loc)); - end if; - - Append_To (Args, Make_Identifier (Loc, Name_uChain)); - - Decl := Last (Decls); - Append_To (Args, - New_Occurrence_Of (Defining_Identifier (Decl), Loc)); - - -- Has_Task is false, Decls not used - - else - Decls := No_List; - end if; - - -- Add discriminants if discriminated type - - declare - Dis : Boolean := False; - Typ : Entity_Id; - - begin - if Has_Discriminants (T) then - Dis := True; - Typ := T; - - elsif Is_Private_Type (T) - and then Present (Full_View (T)) - and then Has_Discriminants (Full_View (T)) - then - Dis := True; - Typ := Full_View (T); - end if; - - if Dis then - - -- If the allocated object will be constrained by the - -- default values for discriminants, then build a subtype - -- with those defaults, and change the allocated subtype - -- to that. Note that this happens in fewer cases in Ada - -- 2005 (AI-363). - - if not Is_Constrained (Typ) - and then Present (Discriminant_Default_Value - (First_Discriminant (Typ))) - and then (Ada_Version < Ada_2005 - or else not - Effectively_Has_Constrained_Partial_View - (Typ => Typ, - Scop => Current_Scope)) - then - Typ := Build_Default_Subtype (Typ, N); - Set_Expression (N, New_Reference_To (Typ, Loc)); - end if; - - Discr := First_Elmt (Discriminant_Constraint (Typ)); - while Present (Discr) loop - Nod := Node (Discr); - Append (New_Copy_Tree (Node (Discr)), Args); - - -- AI-416: when the discriminant constraint is an - -- anonymous access type make sure an accessibility - -- check is inserted if necessary (3.10.2(22.q/2)) - - if Ada_Version >= Ada_2005 - and then - Ekind (Etype (Nod)) = E_Anonymous_Access_Type - then - Apply_Accessibility_Check - (Nod, Typ, Insert_Node => Nod); - end if; - - Next_Elmt (Discr); - end loop; - end if; - end; - - -- We set the allocator as analyzed so that when we analyze - -- the if expression node, we do not get an unwanted recursive - -- expansion of the allocator expression. - - Set_Analyzed (N, True); - Nod := Relocate_Node (N); - - -- Here is the transformation: - -- input: new Ctrl_Typ - -- output: Temp : constant Ctrl_Typ_Ptr := new Ctrl_Typ; - -- Ctrl_TypIP (Temp.all, ...); - -- [Deep_]Initialize (Temp.all); - - -- Here Ctrl_Typ_Ptr is the pointer type for the allocator, and - -- is the subtype of the allocator. - - Temp_Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Constant_Present => True, - Object_Definition => New_Reference_To (Temp_Type, Loc), - Expression => Nod); - - Set_Assignment_OK (Temp_Decl); - Insert_Action (N, Temp_Decl, Suppress => All_Checks); - - Build_Allocate_Deallocate_Proc (Temp_Decl, True); - - -- If the designated type is a task type or contains tasks, - -- create block to activate created tasks, and insert - -- declaration for Task_Image variable ahead of call. - - if Has_Task (T) then - declare - L : constant List_Id := New_List; - Blk : Node_Id; - begin - Build_Task_Allocate_Block (L, Nod, Args); - Blk := Last (L); - Insert_List_Before (First (Declarations (Blk)), Decls); - Insert_Actions (N, L); - end; - - else - Insert_Action (N, - Make_Procedure_Call_Statement (Loc, - Name => New_Reference_To (Init, Loc), - Parameter_Associations => Args)); - end if; - - if Needs_Finalization (T) then - - -- Generate: - -- [Deep_]Initialize (Init_Arg1); - - Insert_Action (N, - Make_Init_Call - (Obj_Ref => New_Copy_Tree (Init_Arg1), - Typ => T)); - - if Present (Finalization_Master (PtrT)) then - - -- Special processing for .NET/JVM, the allocated object - -- is attached to the finalization master. Generate: - - -- Attach (<PtrT>FM, Root_Controlled_Ptr (Init_Arg1)); - - -- Types derived from [Limited_]Controlled are the only - -- ones considered since they have fields Prev and Next. - - if VM_Target /= No_VM then - if Is_Controlled (T) then - Insert_Action (N, - Make_Attach_Call - (Obj_Ref => New_Copy_Tree (Init_Arg1), - Ptr_Typ => PtrT)); - end if; - - -- Default case, generate: - - -- Set_Finalize_Address - -- (<PtrT>FM, <T>FD'Unrestricted_Access); - - -- Do not generate this call in the following cases: - -- - -- * Alfa mode - the call is useless and results in - -- unwanted expansion. - -- - -- * CodePeer mode - TSS primitive Finalize_Address is - -- not created in this mode. - - elsif not Alfa_Mode - and then not CodePeer_Mode - then - Insert_Action (N, - Make_Set_Finalize_Address_Call - (Loc => Loc, - Typ => T, - Ptr_Typ => PtrT)); - end if; - end if; - end if; - - Rewrite (N, New_Reference_To (Temp, Loc)); - Analyze_And_Resolve (N, PtrT); - end if; - end if; - end; - - -- Ada 2005 (AI-251): If the allocator is for a class-wide interface - -- object that has been rewritten as a reference, we displace "this" - -- to reference properly its secondary dispatch table. - - if Nkind (N) = N_Identifier - and then Is_Interface (Dtyp) - then - Displace_Allocator_Pointer (N); - end if; - - exception - when RE_Not_Available => - return; - end Expand_N_Allocator; - - ----------------------- - -- Expand_N_And_Then -- - ----------------------- - - procedure Expand_N_And_Then (N : Node_Id) - renames Expand_Short_Circuit_Operator; - - ------------------------------ - -- Expand_N_Case_Expression -- - ------------------------------ - - procedure Expand_N_Case_Expression (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Cstmt : Node_Id; - Tnn : Entity_Id; - Pnn : Entity_Id; - Actions : List_Id; - Ttyp : Entity_Id; - Alt : Node_Id; - Fexp : Node_Id; - - begin - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- We expand - - -- case X is when A => AX, when B => BX ... - - -- to - - -- do - -- Tnn : typ; - -- case X is - -- when A => - -- Tnn := AX; - -- when B => - -- Tnn := BX; - -- ... - -- end case; - -- in Tnn end; - - -- However, this expansion is wrong for limited types, and also - -- wrong for unconstrained types (since the bounds may not be the - -- same in all branches). Furthermore it involves an extra copy - -- for large objects. So we take care of this by using the following - -- modified expansion for non-elementary types: - - -- do - -- type Pnn is access all typ; - -- Tnn : Pnn; - -- case X is - -- when A => - -- T := AX'Unrestricted_Access; - -- when B => - -- T := BX'Unrestricted_Access; - -- ... - -- end case; - -- in Tnn.all end; - - Cstmt := - Make_Case_Statement (Loc, - Expression => Expression (N), - Alternatives => New_List); - - Actions := New_List; - - -- Scalar case - - if Is_Elementary_Type (Typ) then - Ttyp := Typ; - - else - Pnn := Make_Temporary (Loc, 'P'); - Append_To (Actions, - Make_Full_Type_Declaration (Loc, - Defining_Identifier => Pnn, - Type_Definition => - Make_Access_To_Object_Definition (Loc, - All_Present => True, - Subtype_Indication => - New_Reference_To (Typ, Loc)))); - Ttyp := Pnn; - end if; - - Tnn := Make_Temporary (Loc, 'T'); - Append_To (Actions, - Make_Object_Declaration (Loc, - Defining_Identifier => Tnn, - Object_Definition => New_Occurrence_Of (Ttyp, Loc))); - - -- Now process the alternatives - - Alt := First (Alternatives (N)); - while Present (Alt) loop - declare - Aexp : Node_Id := Expression (Alt); - Aloc : constant Source_Ptr := Sloc (Aexp); - Stats : List_Id; - - begin - -- As described above, take Unrestricted_Access for case of non- - -- scalar types, to avoid big copies, and special cases. - - if not Is_Elementary_Type (Typ) then - Aexp := - Make_Attribute_Reference (Aloc, - Prefix => Relocate_Node (Aexp), - Attribute_Name => Name_Unrestricted_Access); - end if; - - Stats := New_List ( - Make_Assignment_Statement (Aloc, - Name => New_Occurrence_Of (Tnn, Loc), - Expression => Aexp)); - - -- Propagate declarations inserted in the node by Insert_Actions - -- (for example, temporaries generated to remove side effects). - -- These actions must remain attached to the alternative, given - -- that they are generated by the corresponding expression. - - if Present (Sinfo.Actions (Alt)) then - Prepend_List (Sinfo.Actions (Alt), Stats); - end if; - - Append_To - (Alternatives (Cstmt), - Make_Case_Statement_Alternative (Sloc (Alt), - Discrete_Choices => Discrete_Choices (Alt), - Statements => Stats)); - end; - - Next (Alt); - end loop; - - Append_To (Actions, Cstmt); - - -- Construct and return final expression with actions - - if Is_Elementary_Type (Typ) then - Fexp := New_Occurrence_Of (Tnn, Loc); - else - Fexp := - Make_Explicit_Dereference (Loc, - Prefix => New_Occurrence_Of (Tnn, Loc)); - end if; - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Expression => Fexp, - Actions => Actions)); - - Analyze_And_Resolve (N, Typ); - end Expand_N_Case_Expression; - - ----------------------------------- - -- Expand_N_Explicit_Dereference -- - ----------------------------------- - - procedure Expand_N_Explicit_Dereference (N : Node_Id) is - begin - -- Insert explicit dereference call for the checked storage pool case - - Insert_Dereference_Action (Prefix (N)); - - -- If the type is an Atomic type for which Atomic_Sync is enabled, then - -- we set the atomic sync flag. - - if Is_Atomic (Etype (N)) - and then not Atomic_Synchronization_Disabled (Etype (N)) - then - Activate_Atomic_Synchronization (N); - end if; - end Expand_N_Explicit_Dereference; - - -------------------------------------- - -- Expand_N_Expression_With_Actions -- - -------------------------------------- - - procedure Expand_N_Expression_With_Actions (N : Node_Id) is - In_Case_Or_If_Expression : constant Boolean := - Within_Case_Or_If_Expression (N); - - function Process_Action (Act : Node_Id) return Traverse_Result; - -- Inspect and process a single action of an expression_with_actions - - -------------------- - -- Process_Action -- - -------------------- - - function Process_Action (Act : Node_Id) return Traverse_Result is - procedure Process_Transient_Object (Obj_Decl : Node_Id); - -- Obj_Decl denotes the declaration of a transient controlled object. - -- Generate all necessary types and hooks to properly finalize the - -- result when the enclosing context is elaborated/evaluated. - - ------------------------------ - -- Process_Transient_Object -- - ------------------------------ - - procedure Process_Transient_Object (Obj_Decl : Node_Id) is - function Find_Enclosing_Context return Node_Id; - -- Find the context where the expression_with_actions appears - - ---------------------------- - -- Find_Enclosing_Context -- - ---------------------------- - - function Find_Enclosing_Context return Node_Id is - function Is_Body_Or_Unit (N : Node_Id) return Boolean; - -- Determine whether N denotes a body or unit declaration - - --------------------- - -- Is_Body_Or_Unit -- - --------------------- - - function Is_Body_Or_Unit (N : Node_Id) return Boolean is - begin - return Nkind_In (N, N_Entry_Body, - N_Package_Body, - N_Package_Declaration, - N_Protected_Body, - N_Subprogram_Body, - N_Task_Body); - end Is_Body_Or_Unit; - - -- Local variables - - Par : Node_Id; - Top : Node_Id; - - -- Start of processing for Find_Enclosing_Context - - begin - -- The expression_with_actions is in a case/if expression and - -- the lifetime of any temporary controlled object is therefore - -- extended. Find a suitable insertion node by locating the top - -- most case or if expressions. - - if In_Case_Or_If_Expression then - Par := N; - Top := N; - while Present (Par) loop - if Nkind_In (Original_Node (Par), N_Case_Expression, - N_If_Expression) - then - Top := Par; - - -- Prevent the search from going too far - - elsif Is_Body_Or_Unit (Par) then - exit; - end if; - - Par := Parent (Par); - end loop; - - -- The topmost case or if expression is now recovered, but - -- it may still not be the correct place to add all the - -- generated code. Climb to find a parent that is part of a - -- declarative or statement list. - - Par := Top; - while Present (Par) loop - if Is_List_Member (Par) - and then - not Nkind_In (Par, N_Component_Association, - N_Discriminant_Association, - N_Parameter_Association, - N_Pragma_Argument_Association) - then - return Par; - - -- Prevent the search from going too far - - elsif Is_Body_Or_Unit (Par) then - exit; - end if; - - Par := Parent (Par); - end loop; - - return Par; - - -- Short circuit operators in complex expressions are converted - -- into expression_with_actions. - - else - -- Take care of the case where the expression_with_actions - -- is buried deep inside an IF statement. The temporary - -- function result must be finalized before the then, elsif - -- or else statements are evaluated. - - -- if Something - -- and then Ctrl_Func_Call - -- then - -- <result must be finalized at this point> - -- <statements> - -- end if; - - -- To achieve this, find the topmost logical operator. The - -- generated actions are then inserted before/after it. - - Par := N; - while Present (Par) loop - - -- Keep climbing past various operators - - if Nkind (Parent (Par)) in N_Op - or else Nkind_In (Parent (Par), N_And_Then, N_Or_Else) - then - Par := Parent (Par); - else - exit; - end if; - end loop; - - Top := Par; - - -- The expression_with_actions might be located in a pragma - -- in which case locate the pragma itself: - - -- pragma Precondition (... and then Ctrl_Func_Call ...); - - -- Similar case occurs when the expression_with_actions is - -- related to an object declaration or assignment: - - -- Obj [: Some_Typ] := ... and then Ctrl_Func_Call ...; - - -- Another case to consider is an expression_with_actions as - -- part of a return statement: - - -- return ... and then Ctrl_Func_Call ...; - - while Present (Par) loop - if Nkind_In (Par, N_Assignment_Statement, - N_Object_Declaration, - N_Pragma, - N_Simple_Return_Statement) - then - return Par; - - elsif Is_Body_Or_Unit (Par) then - exit; - end if; - - Par := Parent (Par); - end loop; - - -- Return the topmost short circuit operator - - return Top; - end if; - end Find_Enclosing_Context; - - -- Local variables - - Context : constant Node_Id := Find_Enclosing_Context; - Loc : constant Source_Ptr := Sloc (Obj_Decl); - Obj_Id : constant Entity_Id := Defining_Identifier (Obj_Decl); - Obj_Typ : constant Node_Id := Etype (Obj_Id); - Desig_Typ : Entity_Id; - Expr : Node_Id; - Ptr_Id : Entity_Id; - Temp_Id : Entity_Id; - - -- Start of processing for Process_Transient_Object - - begin - -- Step 1: Create the access type which provides a reference to - -- the transient object. - - if Is_Access_Type (Obj_Typ) then - Desig_Typ := Directly_Designated_Type (Obj_Typ); - else - Desig_Typ := Obj_Typ; - end if; - - -- Generate: - -- Ann : access [all] <Desig_Typ>; - - Ptr_Id := Make_Temporary (Loc, 'A'); - - Insert_Action (Context, - Make_Full_Type_Declaration (Loc, - Defining_Identifier => Ptr_Id, - Type_Definition => - Make_Access_To_Object_Definition (Loc, - All_Present => - Ekind (Obj_Typ) = E_General_Access_Type, - Subtype_Indication => New_Reference_To (Desig_Typ, Loc)))); - - -- Step 2: Create a temporary which acts as a hook to the - -- transient object. Generate: - - -- Temp : Ptr_Id := null; - - Temp_Id := Make_Temporary (Loc, 'T'); - - Insert_Action (Context, - Make_Object_Declaration (Loc, - Defining_Identifier => Temp_Id, - Object_Definition => New_Reference_To (Ptr_Id, Loc))); - - -- Mark this temporary as created for the purposes of exporting - -- the transient declaration out of the Actions list. This signals - -- the machinery in Build_Finalizer to recognize this special - -- case. - - Set_Status_Flag_Or_Transient_Decl (Temp_Id, Obj_Decl); - - -- Step 3: Hook the transient object to the temporary - - if Is_Access_Type (Obj_Typ) then - Expr := Convert_To (Ptr_Id, New_Reference_To (Obj_Id, Loc)); - else - Expr := - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Obj_Id, Loc), - Attribute_Name => Name_Unrestricted_Access); - end if; - - -- Generate: - -- Temp := Ptr_Id (Obj_Id); - -- <or> - -- Temp := Obj_Id'Unrestricted_Access; - - Insert_After_And_Analyze (Obj_Decl, - Make_Assignment_Statement (Loc, - Name => New_Reference_To (Temp_Id, Loc), - Expression => Expr)); - - -- Step 4: Finalize the function result after the context has been - -- evaluated/elaborated. Generate: - - -- if Temp /= null then - -- [Deep_]Finalize (Temp.all); - -- Temp := null; - -- end if; - - -- When the expression_with_actions is part of a return statement, - -- there is no need to insert a finalization call, as the general - -- finalization mechanism (see Build_Finalizer) would take care of - -- the temporary function result on subprogram exit. Note that it - -- would also be impossible to insert the finalization code after - -- the return statement as this would make it unreachable. - - if Nkind (Context) /= N_Simple_Return_Statement then - Insert_Action_After (Context, - Make_If_Statement (Loc, - Condition => - Make_Op_Ne (Loc, - Left_Opnd => New_Reference_To (Temp_Id, Loc), - Right_Opnd => Make_Null (Loc)), - - Then_Statements => New_List ( - Make_Final_Call - (Obj_Ref => - Make_Explicit_Dereference (Loc, - Prefix => New_Reference_To (Temp_Id, Loc)), - Typ => Desig_Typ), - - Make_Assignment_Statement (Loc, - Name => New_Reference_To (Temp_Id, Loc), - Expression => Make_Null (Loc))))); - end if; - end Process_Transient_Object; - - -- Start of processing for Process_Action - - begin - if Nkind (Act) = N_Object_Declaration - and then Is_Finalizable_Transient (Act, N) - then - Process_Transient_Object (Act); - - -- Avoid processing temporary function results multiple times when - -- dealing with nested expression_with_actions. - - elsif Nkind (Act) = N_Expression_With_Actions then - return Abandon; - - -- Do not process temporary function results in loops. This is - -- done by Expand_N_Loop_Statement and Build_Finalizer. - - elsif Nkind (Act) = N_Loop_Statement then - return Abandon; - end if; - - return OK; - end Process_Action; - - procedure Process_Single_Action is new Traverse_Proc (Process_Action); - - -- Local variables - - Act : Node_Id; - - -- Start of processing for Expand_N_Expression_With_Actions - - begin - Act := First (Actions (N)); - while Present (Act) loop - Process_Single_Action (Act); - - Next (Act); - end loop; - end Expand_N_Expression_With_Actions; - - ---------------------------- - -- Expand_N_If_Expression -- - ---------------------------- - - -- Deal with limited types and condition actions - - procedure Expand_N_If_Expression (N : Node_Id) is - function Create_Alternative - (Loc : Source_Ptr; - Temp_Id : Entity_Id; - Flag_Id : Entity_Id; - Expr : Node_Id) return List_Id; - -- Build the statements of a "then" or "else" dependent expression - -- alternative. Temp_Id is the if expression result, Flag_Id is a - -- finalization flag created to service expression Expr. - - function Is_Controlled_Function_Call (Expr : Node_Id) return Boolean; - -- Determine if expression Expr is a rewritten controlled function call - - ------------------------ - -- Create_Alternative -- - ------------------------ - - function Create_Alternative - (Loc : Source_Ptr; - Temp_Id : Entity_Id; - Flag_Id : Entity_Id; - Expr : Node_Id) return List_Id - is - Result : constant List_Id := New_List; - - begin - -- Generate: - -- Fnn := True; - - if Present (Flag_Id) - and then not Is_Controlled_Function_Call (Expr) - then - Append_To (Result, - Make_Assignment_Statement (Loc, - Name => New_Reference_To (Flag_Id, Loc), - Expression => New_Reference_To (Standard_True, Loc))); - end if; - - -- Generate: - -- Cnn := <expr>'Unrestricted_Access; - - Append_To (Result, - Make_Assignment_Statement (Loc, - Name => New_Reference_To (Temp_Id, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Expr), - Attribute_Name => Name_Unrestricted_Access))); - - return Result; - end Create_Alternative; - - --------------------------------- - -- Is_Controlled_Function_Call -- - --------------------------------- - - function Is_Controlled_Function_Call (Expr : Node_Id) return Boolean is - begin - return - Nkind (Original_Node (Expr)) = N_Function_Call - and then Needs_Finalization (Etype (Expr)); - end Is_Controlled_Function_Call; - - -- Local variables - - Loc : constant Source_Ptr := Sloc (N); - Cond : constant Node_Id := First (Expressions (N)); - Thenx : constant Node_Id := Next (Cond); - Elsex : constant Node_Id := Next (Thenx); - Typ : constant Entity_Id := Etype (N); - - Actions : List_Id; - Cnn : Entity_Id; - Decl : Node_Id; - Expr : Node_Id; - New_If : Node_Id; - New_N : Node_Id; - - -- Start of processing for Expand_N_If_Expression - - begin - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- Fold at compile time if condition known. We have already folded - -- static if expressions, but it is possible to fold any case in which - -- the condition is known at compile time, even though the result is - -- non-static. - - -- Note that we don't do the fold of such cases in Sem_Elab because - -- it can cause infinite loops with the expander adding a conditional - -- expression, and Sem_Elab circuitry removing it repeatedly. - - if Compile_Time_Known_Value (Cond) then - if Is_True (Expr_Value (Cond)) then - Expr := Thenx; - Actions := Then_Actions (N); - else - Expr := Elsex; - Actions := Else_Actions (N); - end if; - - Remove (Expr); - - if Present (Actions) then - - -- If we are not allowed to use Expression_With_Actions, just skip - -- the optimization, it is not critical for correctness. - - if not Use_Expression_With_Actions then - goto Skip_Optimization; - end if; - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Expression => Relocate_Node (Expr), - Actions => Actions)); - Analyze_And_Resolve (N, Typ); - - else - Rewrite (N, Relocate_Node (Expr)); - end if; - - -- Note that the result is never static (legitimate cases of static - -- if expressions were folded in Sem_Eval). - - Set_Is_Static_Expression (N, False); - return; - end if; - - <<Skip_Optimization>> - - -- If the type is limited or unconstrained, we expand as follows to - -- avoid any possibility of improper copies. - - -- Note: it may be possible to avoid this special processing if the - -- back end uses its own mechanisms for handling by-reference types ??? - - -- type Ptr is access all Typ; - -- Cnn : Ptr; - -- if cond then - -- <<then actions>> - -- Cnn := then-expr'Unrestricted_Access; - -- else - -- <<else actions>> - -- Cnn := else-expr'Unrestricted_Access; - -- end if; - - -- and replace the if expression by a reference to Cnn.all. - - -- This special case can be skipped if the back end handles limited - -- types properly and ensures that no incorrect copies are made. - - if Is_By_Reference_Type (Typ) - and then not Back_End_Handles_Limited_Types - then - declare - Flag_Id : Entity_Id; - Ptr_Typ : Entity_Id; - - begin - Flag_Id := Empty; - - -- At least one of the if expression dependent expressions uses a - -- controlled function to provide the result. Create a status flag - -- to signal the finalization machinery that Cnn needs special - -- handling. - - if Is_Controlled_Function_Call (Thenx) - or else - Is_Controlled_Function_Call (Elsex) - then - Flag_Id := Make_Temporary (Loc, 'F'); - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => Flag_Id, - Object_Definition => - New_Reference_To (Standard_Boolean, Loc), - Expression => - New_Reference_To (Standard_False, Loc))); - end if; - - -- Generate: - -- type Ann is access all Typ; - - Ptr_Typ := Make_Temporary (Loc, 'A'); - - Insert_Action (N, - Make_Full_Type_Declaration (Loc, - Defining_Identifier => Ptr_Typ, - Type_Definition => - Make_Access_To_Object_Definition (Loc, - All_Present => True, - Subtype_Indication => New_Reference_To (Typ, Loc)))); - - -- Generate: - -- Cnn : Ann; - - Cnn := Make_Temporary (Loc, 'C', N); - Set_Ekind (Cnn, E_Variable); - Set_Status_Flag_Or_Transient_Decl (Cnn, Flag_Id); - - Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Cnn, - Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc)); - - New_If := - Make_Implicit_If_Statement (N, - Condition => Relocate_Node (Cond), - Then_Statements => - Create_Alternative (Sloc (Thenx), Cnn, Flag_Id, Thenx), - Else_Statements => - Create_Alternative (Sloc (Elsex), Cnn, Flag_Id, Elsex)); - - New_N := - Make_Explicit_Dereference (Loc, - Prefix => New_Occurrence_Of (Cnn, Loc)); - end; - - -- For other types, we only need to expand if there are other actions - -- associated with either branch. - - elsif Present (Then_Actions (N)) or else Present (Else_Actions (N)) then - - -- We have two approaches to handling this. If we are allowed to use - -- N_Expression_With_Actions, then we can just wrap the actions into - -- the appropriate expression. - - if Use_Expression_With_Actions then - if Present (Then_Actions (N)) then - Rewrite (Thenx, - Make_Expression_With_Actions (Sloc (Thenx), - Actions => Then_Actions (N), - Expression => Relocate_Node (Thenx))); - Set_Then_Actions (N, No_List); - Analyze_And_Resolve (Thenx, Typ); - end if; - - if Present (Else_Actions (N)) then - Rewrite (Elsex, - Make_Expression_With_Actions (Sloc (Elsex), - Actions => Else_Actions (N), - Expression => Relocate_Node (Elsex))); - Set_Else_Actions (N, No_List); - Analyze_And_Resolve (Elsex, Typ); - end if; - - return; - - -- if we can't use N_Expression_With_Actions nodes, then we insert - -- the following sequence of actions (using Insert_Actions): - - -- Cnn : typ; - -- if cond then - -- <<then actions>> - -- Cnn := then-expr; - -- else - -- <<else actions>> - -- Cnn := else-expr - -- end if; - - -- and replace the if expression by a reference to Cnn - - else - Cnn := Make_Temporary (Loc, 'C', N); - - Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Cnn, - Object_Definition => New_Occurrence_Of (Typ, Loc)); - - New_If := - Make_Implicit_If_Statement (N, - Condition => Relocate_Node (Cond), - - Then_Statements => New_List ( - Make_Assignment_Statement (Sloc (Thenx), - Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), - Expression => Relocate_Node (Thenx))), - - Else_Statements => New_List ( - Make_Assignment_Statement (Sloc (Elsex), - Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), - Expression => Relocate_Node (Elsex)))); - - Set_Assignment_OK (Name (First (Then_Statements (New_If)))); - Set_Assignment_OK (Name (First (Else_Statements (New_If)))); - - New_N := New_Occurrence_Of (Cnn, Loc); - end if; - - -- If no actions then no expansion needed, gigi will handle it using - -- the same approach as a C conditional expression. - - else - return; - end if; - - -- Fall through here for either the limited expansion, or the case of - -- inserting actions for non-limited types. In both these cases, we must - -- move the SLOC of the parent If statement to the newly created one and - -- change it to the SLOC of the expression which, after expansion, will - -- correspond to what is being evaluated. - - if Present (Parent (N)) - and then Nkind (Parent (N)) = N_If_Statement - then - Set_Sloc (New_If, Sloc (Parent (N))); - Set_Sloc (Parent (N), Loc); - end if; - - -- Make sure Then_Actions and Else_Actions are appropriately moved - -- to the new if statement. - - if Present (Then_Actions (N)) then - Insert_List_Before - (First (Then_Statements (New_If)), Then_Actions (N)); - end if; - - if Present (Else_Actions (N)) then - Insert_List_Before - (First (Else_Statements (New_If)), Else_Actions (N)); - end if; - - Insert_Action (N, Decl); - Insert_Action (N, New_If); - Rewrite (N, New_N); - Analyze_And_Resolve (N, Typ); - end Expand_N_If_Expression; - - ----------------- - -- Expand_N_In -- - ----------------- - - procedure Expand_N_In (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Restyp : constant Entity_Id := Etype (N); - Lop : constant Node_Id := Left_Opnd (N); - Rop : constant Node_Id := Right_Opnd (N); - Static : constant Boolean := Is_OK_Static_Expression (N); - - Ltyp : Entity_Id; - Rtyp : Entity_Id; - - procedure Substitute_Valid_Check; - -- Replaces node N by Lop'Valid. This is done when we have an explicit - -- test for the left operand being in range of its subtype. - - ---------------------------- - -- Substitute_Valid_Check -- - ---------------------------- - - procedure Substitute_Valid_Check is - begin - Rewrite (N, - Make_Attribute_Reference (Loc, - Prefix => Relocate_Node (Lop), - Attribute_Name => Name_Valid)); - - Analyze_And_Resolve (N, Restyp); - - -- Give warning unless overflow checking is MINIMIZED or ELIMINATED, - -- in which case, this usage makes sense, and in any case, we have - -- actually eliminated the danger of optimization above. - - if Overflow_Check_Mode not in Minimized_Or_Eliminated then - Error_Msg_N - ("??explicit membership test may be optimized away", N); - Error_Msg_N -- CODEFIX - ("\??use ''Valid attribute instead", N); - end if; - - return; - end Substitute_Valid_Check; - - -- Start of processing for Expand_N_In - - begin - -- If set membership case, expand with separate procedure - - if Present (Alternatives (N)) then - Expand_Set_Membership (N); - return; - end if; - - -- Not set membership, proceed with expansion - - Ltyp := Etype (Left_Opnd (N)); - Rtyp := Etype (Right_Opnd (N)); - - -- If MINIMIZED/ELIMINATED overflow mode and type is a signed integer - -- type, then expand with a separate procedure. Note the use of the - -- flag No_Minimize_Eliminate to prevent infinite recursion. - - if Overflow_Check_Mode in Minimized_Or_Eliminated - and then Is_Signed_Integer_Type (Ltyp) - and then not No_Minimize_Eliminate (N) - then - Expand_Membership_Minimize_Eliminate_Overflow (N); - return; - end if; - - -- Check case of explicit test for an expression in range of its - -- subtype. This is suspicious usage and we replace it with a 'Valid - -- test and give a warning for scalar types. - - if Is_Scalar_Type (Ltyp) - - -- Only relevant for source comparisons - - and then Comes_From_Source (N) - - -- In floating-point this is a standard way to check for finite values - -- and using 'Valid would typically be a pessimization. - - and then not Is_Floating_Point_Type (Ltyp) - - -- Don't give the message unless right operand is a type entity and - -- the type of the left operand matches this type. Note that this - -- eliminates the cases where MINIMIZED/ELIMINATED mode overflow - -- checks have changed the type of the left operand. - - and then Nkind (Rop) in N_Has_Entity - and then Ltyp = Entity (Rop) - - -- Skip in VM mode, where we have no sense of invalid values. The - -- warning still seems relevant, but not important enough to worry. - - and then VM_Target = No_VM - - -- Skip this for predicated types, where such expressions are a - -- reasonable way of testing if something meets the predicate. - - and then not Present (Predicate_Function (Ltyp)) - then - Substitute_Valid_Check; - return; - end if; - - -- Do validity check on operands - - if Validity_Checks_On and Validity_Check_Operands then - Ensure_Valid (Left_Opnd (N)); - Validity_Check_Range (Right_Opnd (N)); - end if; - - -- Case of explicit range - - if Nkind (Rop) = N_Range then - declare - Lo : constant Node_Id := Low_Bound (Rop); - Hi : constant Node_Id := High_Bound (Rop); - - Lo_Orig : constant Node_Id := Original_Node (Lo); - Hi_Orig : constant Node_Id := Original_Node (Hi); - - Lcheck : Compare_Result; - Ucheck : Compare_Result; - - Warn1 : constant Boolean := - Constant_Condition_Warnings - and then Comes_From_Source (N) - and then not In_Instance; - -- This must be true for any of the optimization warnings, we - -- clearly want to give them only for source with the flag on. We - -- also skip these warnings in an instance since it may be the - -- case that different instantiations have different ranges. - - Warn2 : constant Boolean := - Warn1 - and then Nkind (Original_Node (Rop)) = N_Range - and then Is_Integer_Type (Etype (Lo)); - -- For the case where only one bound warning is elided, we also - -- insist on an explicit range and an integer type. The reason is - -- that the use of enumeration ranges including an end point is - -- common, as is the use of a subtype name, one of whose bounds is - -- the same as the type of the expression. - - begin - -- If test is explicit x'First .. x'Last, replace by valid check - - -- Could use some individual comments for this complex test ??? - - if Is_Scalar_Type (Ltyp) - - -- And left operand is X'First where X matches left operand - -- type (this eliminates cases of type mismatch, including - -- the cases where ELIMINATED/MINIMIZED mode has changed the - -- type of the left operand. - - and then Nkind (Lo_Orig) = N_Attribute_Reference - and then Attribute_Name (Lo_Orig) = Name_First - and then Nkind (Prefix (Lo_Orig)) in N_Has_Entity - and then Entity (Prefix (Lo_Orig)) = Ltyp - - -- Same tests for right operand - - and then Nkind (Hi_Orig) = N_Attribute_Reference - and then Attribute_Name (Hi_Orig) = Name_Last - and then Nkind (Prefix (Hi_Orig)) in N_Has_Entity - and then Entity (Prefix (Hi_Orig)) = Ltyp - - -- Relevant only for source cases - - and then Comes_From_Source (N) - - -- Omit for VM cases, where we don't have invalid values - - and then VM_Target = No_VM - then - Substitute_Valid_Check; - goto Leave; - end if; - - -- If bounds of type are known at compile time, and the end points - -- are known at compile time and identical, this is another case - -- for substituting a valid test. We only do this for discrete - -- types, since it won't arise in practice for float types. - - if Comes_From_Source (N) - and then Is_Discrete_Type (Ltyp) - and then Compile_Time_Known_Value (Type_High_Bound (Ltyp)) - and then Compile_Time_Known_Value (Type_Low_Bound (Ltyp)) - and then Compile_Time_Known_Value (Lo) - and then Compile_Time_Known_Value (Hi) - and then Expr_Value (Type_High_Bound (Ltyp)) = Expr_Value (Hi) - and then Expr_Value (Type_Low_Bound (Ltyp)) = Expr_Value (Lo) - - -- Kill warnings in instances, since they may be cases where we - -- have a test in the generic that makes sense with some types - -- and not with other types. - - and then not In_Instance - then - Substitute_Valid_Check; - goto Leave; - end if; - - -- If we have an explicit range, do a bit of optimization based on - -- range analysis (we may be able to kill one or both checks). - - Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => False); - Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => False); - - -- If either check is known to fail, replace result by False since - -- the other check does not matter. Preserve the static flag for - -- legality checks, because we are constant-folding beyond RM 4.9. - - if Lcheck = LT or else Ucheck = GT then - if Warn1 then - Error_Msg_N ("?c?range test optimized away", N); - Error_Msg_N ("\?c?value is known to be out of range", N); - end if; - - Rewrite (N, New_Reference_To (Standard_False, Loc)); - Analyze_And_Resolve (N, Restyp); - Set_Is_Static_Expression (N, Static); - goto Leave; - - -- If both checks are known to succeed, replace result by True, - -- since we know we are in range. - - elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then - if Warn1 then - Error_Msg_N ("?c?range test optimized away", N); - Error_Msg_N ("\?c?value is known to be in range", N); - end if; - - Rewrite (N, New_Reference_To (Standard_True, Loc)); - Analyze_And_Resolve (N, Restyp); - Set_Is_Static_Expression (N, Static); - goto Leave; - - -- If lower bound check succeeds and upper bound check is not - -- known to succeed or fail, then replace the range check with - -- a comparison against the upper bound. - - elsif Lcheck in Compare_GE then - if Warn2 and then not In_Instance then - Error_Msg_N ("??lower bound test optimized away", Lo); - Error_Msg_N ("\??value is known to be in range", Lo); - end if; - - Rewrite (N, - Make_Op_Le (Loc, - Left_Opnd => Lop, - Right_Opnd => High_Bound (Rop))); - Analyze_And_Resolve (N, Restyp); - goto Leave; - - -- If upper bound check succeeds and lower bound check is not - -- known to succeed or fail, then replace the range check with - -- a comparison against the lower bound. - - elsif Ucheck in Compare_LE then - if Warn2 and then not In_Instance then - Error_Msg_N ("??upper bound test optimized away", Hi); - Error_Msg_N ("\??value is known to be in range", Hi); - end if; - - Rewrite (N, - Make_Op_Ge (Loc, - Left_Opnd => Lop, - Right_Opnd => Low_Bound (Rop))); - Analyze_And_Resolve (N, Restyp); - goto Leave; - end if; - - -- We couldn't optimize away the range check, but there is one - -- more issue. If we are checking constant conditionals, then we - -- see if we can determine the outcome assuming everything is - -- valid, and if so give an appropriate warning. - - if Warn1 and then not Assume_No_Invalid_Values then - Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => True); - Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => True); - - -- Result is out of range for valid value - - if Lcheck = LT or else Ucheck = GT then - Error_Msg_N - ("?c?value can only be in range if it is invalid", N); - - -- Result is in range for valid value - - elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then - Error_Msg_N - ("?c?value can only be out of range if it is invalid", N); - - -- Lower bound check succeeds if value is valid - - elsif Warn2 and then Lcheck in Compare_GE then - Error_Msg_N - ("?c?lower bound check only fails if it is invalid", Lo); - - -- Upper bound check succeeds if value is valid - - elsif Warn2 and then Ucheck in Compare_LE then - Error_Msg_N - ("?c?upper bound check only fails for invalid values", Hi); - end if; - end if; - end; - - -- For all other cases of an explicit range, nothing to be done - - goto Leave; - - -- Here right operand is a subtype mark - - else - declare - Typ : Entity_Id := Etype (Rop); - Is_Acc : constant Boolean := Is_Access_Type (Typ); - Cond : Node_Id := Empty; - New_N : Node_Id; - Obj : Node_Id := Lop; - SCIL_Node : Node_Id; - - begin - Remove_Side_Effects (Obj); - - -- For tagged type, do tagged membership operation - - if Is_Tagged_Type (Typ) then - - -- No expansion will be performed when VM_Target, as the VM - -- back-ends will handle the membership tests directly (tags - -- are not explicitly represented in Java objects, so the - -- normal tagged membership expansion is not what we want). - - if Tagged_Type_Expansion then - Tagged_Membership (N, SCIL_Node, New_N); - Rewrite (N, New_N); - Analyze_And_Resolve (N, Restyp); - - -- Update decoration of relocated node referenced by the - -- SCIL node. - - if Generate_SCIL and then Present (SCIL_Node) then - Set_SCIL_Node (N, SCIL_Node); - end if; - end if; - - goto Leave; - - -- If type is scalar type, rewrite as x in t'First .. t'Last. - -- This reason we do this is that the bounds may have the wrong - -- type if they come from the original type definition. Also this - -- way we get all the processing above for an explicit range. - - -- Don't do this for predicated types, since in this case we - -- want to check the predicate! - - elsif Is_Scalar_Type (Typ) then - if No (Predicate_Function (Typ)) then - Rewrite (Rop, - Make_Range (Loc, - Low_Bound => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => New_Reference_To (Typ, Loc)), - - High_Bound => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => New_Reference_To (Typ, Loc)))); - Analyze_And_Resolve (N, Restyp); - end if; - - goto Leave; - - -- Ada 2005 (AI-216): Program_Error is raised when evaluating - -- a membership test if the subtype mark denotes a constrained - -- Unchecked_Union subtype and the expression lacks inferable - -- discriminants. - - elsif Is_Unchecked_Union (Base_Type (Typ)) - and then Is_Constrained (Typ) - and then not Has_Inferable_Discriminants (Lop) - then - Insert_Action (N, - Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction)); - - -- Prevent Gigi from generating incorrect code by rewriting the - -- test as False. What is this undocumented thing about ??? - - Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); - goto Leave; - end if; - - -- Here we have a non-scalar type - - if Is_Acc then - Typ := Designated_Type (Typ); - end if; - - if not Is_Constrained (Typ) then - Rewrite (N, New_Reference_To (Standard_True, Loc)); - Analyze_And_Resolve (N, Restyp); - - -- For the constrained array case, we have to check the subscripts - -- for an exact match if the lengths are non-zero (the lengths - -- must match in any case). - - elsif Is_Array_Type (Typ) then - Check_Subscripts : declare - function Build_Attribute_Reference - (E : Node_Id; - Nam : Name_Id; - Dim : Nat) return Node_Id; - -- Build attribute reference E'Nam (Dim) - - ------------------------------- - -- Build_Attribute_Reference -- - ------------------------------- - - function Build_Attribute_Reference - (E : Node_Id; - Nam : Name_Id; - Dim : Nat) return Node_Id - is - begin - return - Make_Attribute_Reference (Loc, - Prefix => E, - Attribute_Name => Nam, - Expressions => New_List ( - Make_Integer_Literal (Loc, Dim))); - end Build_Attribute_Reference; - - -- Start of processing for Check_Subscripts - - begin - for J in 1 .. Number_Dimensions (Typ) loop - Evolve_And_Then (Cond, - Make_Op_Eq (Loc, - Left_Opnd => - Build_Attribute_Reference - (Duplicate_Subexpr_No_Checks (Obj), - Name_First, J), - Right_Opnd => - Build_Attribute_Reference - (New_Occurrence_Of (Typ, Loc), Name_First, J))); - - Evolve_And_Then (Cond, - Make_Op_Eq (Loc, - Left_Opnd => - Build_Attribute_Reference - (Duplicate_Subexpr_No_Checks (Obj), - Name_Last, J), - Right_Opnd => - Build_Attribute_Reference - (New_Occurrence_Of (Typ, Loc), Name_Last, J))); - end loop; - - if Is_Acc then - Cond := - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Eq (Loc, - Left_Opnd => Obj, - Right_Opnd => Make_Null (Loc)), - Right_Opnd => Cond); - end if; - - Rewrite (N, Cond); - Analyze_And_Resolve (N, Restyp); - end Check_Subscripts; - - -- These are the cases where constraint checks may be required, - -- e.g. records with possible discriminants - - else - -- Expand the test into a series of discriminant comparisons. - -- The expression that is built is the negation of the one that - -- is used for checking discriminant constraints. - - Obj := Relocate_Node (Left_Opnd (N)); - - if Has_Discriminants (Typ) then - Cond := Make_Op_Not (Loc, - Right_Opnd => Build_Discriminant_Checks (Obj, Typ)); - - if Is_Acc then - Cond := Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Eq (Loc, - Left_Opnd => Obj, - Right_Opnd => Make_Null (Loc)), - Right_Opnd => Cond); - end if; - - else - Cond := New_Occurrence_Of (Standard_True, Loc); - end if; - - Rewrite (N, Cond); - Analyze_And_Resolve (N, Restyp); - end if; - - -- Ada 2012 (AI05-0149): Handle membership tests applied to an - -- expression of an anonymous access type. This can involve an - -- accessibility test and a tagged type membership test in the - -- case of tagged designated types. - - if Ada_Version >= Ada_2012 - and then Is_Acc - and then Ekind (Ltyp) = E_Anonymous_Access_Type - then - declare - Expr_Entity : Entity_Id := Empty; - New_N : Node_Id; - Param_Level : Node_Id; - Type_Level : Node_Id; - - begin - if Is_Entity_Name (Lop) then - Expr_Entity := Param_Entity (Lop); - - if not Present (Expr_Entity) then - Expr_Entity := Entity (Lop); - end if; - end if; - - -- If a conversion of the anonymous access value to the - -- tested type would be illegal, then the result is False. - - if not Valid_Conversion - (Lop, Rtyp, Lop, Report_Errs => False) - then - Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); - Analyze_And_Resolve (N, Restyp); - - -- Apply an accessibility check if the access object has an - -- associated access level and when the level of the type is - -- less deep than the level of the access parameter. This - -- only occur for access parameters and stand-alone objects - -- of an anonymous access type. - - else - if Present (Expr_Entity) - and then - Present - (Effective_Extra_Accessibility (Expr_Entity)) - and then UI_Gt (Object_Access_Level (Lop), - Type_Access_Level (Rtyp)) - then - Param_Level := - New_Occurrence_Of - (Effective_Extra_Accessibility (Expr_Entity), Loc); - - Type_Level := - Make_Integer_Literal (Loc, Type_Access_Level (Rtyp)); - - -- Return True only if the accessibility level of the - -- expression entity is not deeper than the level of - -- the tested access type. - - Rewrite (N, - Make_And_Then (Loc, - Left_Opnd => Relocate_Node (N), - Right_Opnd => Make_Op_Le (Loc, - Left_Opnd => Param_Level, - Right_Opnd => Type_Level))); - - Analyze_And_Resolve (N); - end if; - - -- If the designated type is tagged, do tagged membership - -- operation. - - -- *** NOTE: we have to check not null before doing the - -- tagged membership test (but maybe that can be done - -- inside Tagged_Membership?). - - if Is_Tagged_Type (Typ) then - Rewrite (N, - Make_And_Then (Loc, - Left_Opnd => Relocate_Node (N), - Right_Opnd => - Make_Op_Ne (Loc, - Left_Opnd => Obj, - Right_Opnd => Make_Null (Loc)))); - - -- No expansion will be performed when VM_Target, as - -- the VM back-ends will handle the membership tests - -- directly (tags are not explicitly represented in - -- Java objects, so the normal tagged membership - -- expansion is not what we want). - - if Tagged_Type_Expansion then - - -- Note that we have to pass Original_Node, because - -- the membership test might already have been - -- rewritten by earlier parts of membership test. - - Tagged_Membership - (Original_Node (N), SCIL_Node, New_N); - - -- Update decoration of relocated node referenced - -- by the SCIL node. - - if Generate_SCIL and then Present (SCIL_Node) then - Set_SCIL_Node (New_N, SCIL_Node); - end if; - - Rewrite (N, - Make_And_Then (Loc, - Left_Opnd => Relocate_Node (N), - Right_Opnd => New_N)); - - Analyze_And_Resolve (N, Restyp); - end if; - end if; - end if; - end; - end if; - end; - end if; - - -- At this point, we have done the processing required for the basic - -- membership test, but not yet dealt with the predicate. - - <<Leave>> - - -- If a predicate is present, then we do the predicate test, but we - -- most certainly want to omit this if we are within the predicate - -- function itself, since otherwise we have an infinite recursion! - -- The check should also not be emitted when testing against a range - -- (the check is only done when the right operand is a subtype; see - -- RM12-4.5.2 (28.1/3-30/3)). - - declare - PFunc : constant Entity_Id := Predicate_Function (Rtyp); - - begin - if Present (PFunc) - and then Current_Scope /= PFunc - and then Nkind (Rop) /= N_Range - then - Rewrite (N, - Make_And_Then (Loc, - Left_Opnd => Relocate_Node (N), - Right_Opnd => Make_Predicate_Call (Rtyp, Lop))); - - -- Analyze new expression, mark left operand as analyzed to - -- avoid infinite recursion adding predicate calls. Similarly, - -- suppress further range checks on the call. - - Set_Analyzed (Left_Opnd (N)); - Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); - - -- All done, skip attempt at compile time determination of result - - return; - end if; - end; - end Expand_N_In; - - -------------------------------- - -- Expand_N_Indexed_Component -- - -------------------------------- - - procedure Expand_N_Indexed_Component (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - P : constant Node_Id := Prefix (N); - T : constant Entity_Id := Etype (P); - Atp : Entity_Id; - - begin - -- A special optimization, if we have an indexed component that is - -- selecting from a slice, then we can eliminate the slice, since, for - -- example, x (i .. j)(k) is identical to x(k). The only difference is - -- the range check required by the slice. The range check for the slice - -- itself has already been generated. The range check for the - -- subscripting operation is ensured by converting the subject to - -- the subtype of the slice. - - -- This optimization not only generates better code, avoiding slice - -- messing especially in the packed case, but more importantly bypasses - -- some problems in handling this peculiar case, for example, the issue - -- of dealing specially with object renamings. - - if Nkind (P) = N_Slice then - Rewrite (N, - Make_Indexed_Component (Loc, - Prefix => Prefix (P), - Expressions => New_List ( - Convert_To - (Etype (First_Index (Etype (P))), - First (Expressions (N)))))); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place - -- function, then additional actuals must be passed. - - if Ada_Version >= Ada_2005 - and then Is_Build_In_Place_Function_Call (P) - then - Make_Build_In_Place_Call_In_Anonymous_Context (P); - end if; - - -- If the prefix is an access type, then we unconditionally rewrite if - -- as an explicit dereference. This simplifies processing for several - -- cases, including packed array cases and certain cases in which checks - -- must be generated. We used to try to do this only when it was - -- necessary, but it cleans up the code to do it all the time. - - if Is_Access_Type (T) then - Insert_Explicit_Dereference (P); - Analyze_And_Resolve (P, Designated_Type (T)); - Atp := Designated_Type (T); - else - Atp := T; - end if; - - -- Generate index and validity checks - - Generate_Index_Checks (N); - - if Validity_Checks_On and then Validity_Check_Subscripts then - Apply_Subscript_Validity_Checks (N); - end if; - - -- If selecting from an array with atomic components, and atomic sync - -- is not suppressed for this array type, set atomic sync flag. - - if (Has_Atomic_Components (Atp) - and then not Atomic_Synchronization_Disabled (Atp)) - or else (Is_Atomic (Typ) - and then not Atomic_Synchronization_Disabled (Typ)) - then - Activate_Atomic_Synchronization (N); - end if; - - -- All done for the non-packed case - - if not Is_Packed (Etype (Prefix (N))) then - return; - end if; - - -- For packed arrays that are not bit-packed (i.e. the case of an array - -- with one or more index types with a non-contiguous enumeration type), - -- we can always use the normal packed element get circuit. - - if not Is_Bit_Packed_Array (Etype (Prefix (N))) then - Expand_Packed_Element_Reference (N); - return; - end if; - - -- For a reference to a component of a bit packed array, we have to - -- convert it to a reference to the corresponding Packed_Array_Type. - -- We only want to do this for simple references, and not for: - - -- Left side of assignment, or prefix of left side of assignment, or - -- prefix of the prefix, to handle packed arrays of packed arrays, - -- This case is handled in Exp_Ch5.Expand_N_Assignment_Statement - - -- Renaming objects in renaming associations - -- This case is handled when a use of the renamed variable occurs - - -- Actual parameters for a procedure call - -- This case is handled in Exp_Ch6.Expand_Actuals - - -- The second expression in a 'Read attribute reference - - -- The prefix of an address or bit or size attribute reference - - -- The following circuit detects these exceptions - - declare - Child : Node_Id := N; - Parnt : Node_Id := Parent (N); - - begin - loop - if Nkind (Parnt) = N_Unchecked_Expression then - null; - - elsif Nkind_In (Parnt, N_Object_Renaming_Declaration, - N_Procedure_Call_Statement) - or else (Nkind (Parnt) = N_Parameter_Association - and then - Nkind (Parent (Parnt)) = N_Procedure_Call_Statement) - then - return; - - elsif Nkind (Parnt) = N_Attribute_Reference - and then (Attribute_Name (Parnt) = Name_Address - or else - Attribute_Name (Parnt) = Name_Bit - or else - Attribute_Name (Parnt) = Name_Size) - and then Prefix (Parnt) = Child - then - return; - - elsif Nkind (Parnt) = N_Assignment_Statement - and then Name (Parnt) = Child - then - return; - - -- If the expression is an index of an indexed component, it must - -- be expanded regardless of context. - - elsif Nkind (Parnt) = N_Indexed_Component - and then Child /= Prefix (Parnt) - then - Expand_Packed_Element_Reference (N); - return; - - elsif Nkind (Parent (Parnt)) = N_Assignment_Statement - and then Name (Parent (Parnt)) = Parnt - then - return; - - elsif Nkind (Parnt) = N_Attribute_Reference - and then Attribute_Name (Parnt) = Name_Read - and then Next (First (Expressions (Parnt))) = Child - then - return; - - elsif Nkind_In (Parnt, N_Indexed_Component, N_Selected_Component) - and then Prefix (Parnt) = Child - then - null; - - else - Expand_Packed_Element_Reference (N); - return; - end if; - - -- Keep looking up tree for unchecked expression, or if we are the - -- prefix of a possible assignment left side. - - Child := Parnt; - Parnt := Parent (Child); - end loop; - end; - end Expand_N_Indexed_Component; - - --------------------- - -- Expand_N_Not_In -- - --------------------- - - -- Replace a not in b by not (a in b) so that the expansions for (a in b) - -- can be done. This avoids needing to duplicate this expansion code. - - procedure Expand_N_Not_In (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Cfs : constant Boolean := Comes_From_Source (N); - - begin - Rewrite (N, - Make_Op_Not (Loc, - Right_Opnd => - Make_In (Loc, - Left_Opnd => Left_Opnd (N), - Right_Opnd => Right_Opnd (N)))); - - -- If this is a set membership, preserve list of alternatives - - Set_Alternatives (Right_Opnd (N), Alternatives (Original_Node (N))); - - -- We want this to appear as coming from source if original does (see - -- transformations in Expand_N_In). - - Set_Comes_From_Source (N, Cfs); - Set_Comes_From_Source (Right_Opnd (N), Cfs); - - -- Now analyze transformed node - - Analyze_And_Resolve (N, Typ); - end Expand_N_Not_In; - - ------------------- - -- Expand_N_Null -- - ------------------- - - -- The only replacement required is for the case of a null of a type that - -- is an access to protected subprogram, or a subtype thereof. We represent - -- such access values as a record, and so we must replace the occurrence of - -- null by the equivalent record (with a null address and a null pointer in - -- it), so that the backend creates the proper value. - - procedure Expand_N_Null (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Base_Type (Etype (N)); - Agg : Node_Id; - - begin - if Is_Access_Protected_Subprogram_Type (Typ) then - Agg := - Make_Aggregate (Loc, - Expressions => New_List ( - New_Occurrence_Of (RTE (RE_Null_Address), Loc), - Make_Null (Loc))); - - Rewrite (N, Agg); - Analyze_And_Resolve (N, Equivalent_Type (Typ)); - - -- For subsequent semantic analysis, the node must retain its type. - -- Gigi in any case replaces this type by the corresponding record - -- type before processing the node. - - Set_Etype (N, Typ); - end if; - - exception - when RE_Not_Available => - return; - end Expand_N_Null; - - --------------------- - -- Expand_N_Op_Abs -- - --------------------- - - procedure Expand_N_Op_Abs (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Expr : constant Node_Id := Right_Opnd (N); - - begin - Unary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- Deal with software overflow checking - - if not Backend_Overflow_Checks_On_Target - and then Is_Signed_Integer_Type (Etype (N)) - and then Do_Overflow_Check (N) - then - -- The only case to worry about is when the argument is equal to the - -- largest negative number, so what we do is to insert the check: - - -- [constraint_error when Expr = typ'Base'First] - - -- with the usual Duplicate_Subexpr use coding for expr - - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Expr), - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => - New_Occurrence_Of (Base_Type (Etype (Expr)), Loc), - Attribute_Name => Name_First)), - Reason => CE_Overflow_Check_Failed)); - end if; - - -- Vax floating-point types case - - if Vax_Float (Etype (N)) then - Expand_Vax_Arith (N); - end if; - end Expand_N_Op_Abs; - - --------------------- - -- Expand_N_Op_Add -- - --------------------- - - procedure Expand_N_Op_Add (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- N + 0 = 0 + N = N for integer types - - if Is_Integer_Type (Typ) then - if Compile_Time_Known_Value (Right_Opnd (N)) - and then Expr_Value (Right_Opnd (N)) = Uint_0 - then - Rewrite (N, Left_Opnd (N)); - return; - - elsif Compile_Time_Known_Value (Left_Opnd (N)) - and then Expr_Value (Left_Opnd (N)) = Uint_0 - then - Rewrite (N, Right_Opnd (N)); - return; - end if; - end if; - - -- Arithmetic overflow checks for signed integer/fixed point types - - if Is_Signed_Integer_Type (Typ) - or else Is_Fixed_Point_Type (Typ) - then - Apply_Arithmetic_Overflow_Check (N); - return; - - -- Vax floating-point types case - - elsif Vax_Float (Typ) then - Expand_Vax_Arith (N); - end if; - end Expand_N_Op_Add; - - --------------------- - -- Expand_N_Op_And -- - --------------------- - - procedure Expand_N_Op_And (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - if Is_Array_Type (Etype (N)) then - Expand_Boolean_Operator (N); - - elsif Is_Boolean_Type (Etype (N)) then - Adjust_Condition (Left_Opnd (N)); - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - - elsif Is_Intrinsic_Subprogram (Entity (N)) then - Expand_Intrinsic_Call (N, Entity (N)); - - end if; - end Expand_N_Op_And; - - ------------------------ - -- Expand_N_Op_Concat -- - ------------------------ - - procedure Expand_N_Op_Concat (N : Node_Id) is - Opnds : List_Id; - -- List of operands to be concatenated - - Cnode : Node_Id; - -- Node which is to be replaced by the result of concatenating the nodes - -- in the list Opnds. - - begin - -- Ensure validity of both operands - - Binary_Op_Validity_Checks (N); - - -- If we are the left operand of a concatenation higher up the tree, - -- then do nothing for now, since we want to deal with a series of - -- concatenations as a unit. - - if Nkind (Parent (N)) = N_Op_Concat - and then N = Left_Opnd (Parent (N)) - then - return; - end if; - - -- We get here with a concatenation whose left operand may be a - -- concatenation itself with a consistent type. We need to process - -- these concatenation operands from left to right, which means - -- from the deepest node in the tree to the highest node. - - Cnode := N; - while Nkind (Left_Opnd (Cnode)) = N_Op_Concat loop - Cnode := Left_Opnd (Cnode); - end loop; - - -- Now Cnode is the deepest concatenation, and its parents are the - -- concatenation nodes above, so now we process bottom up, doing the - -- operations. We gather a string that is as long as possible up to five - -- operands. - - -- The outer loop runs more than once if more than one concatenation - -- type is involved. - - Outer : loop - Opnds := New_List (Left_Opnd (Cnode), Right_Opnd (Cnode)); - Set_Parent (Opnds, N); - - -- The inner loop gathers concatenation operands - - Inner : while Cnode /= N - and then Base_Type (Etype (Cnode)) = - Base_Type (Etype (Parent (Cnode))) - loop - Cnode := Parent (Cnode); - Append (Right_Opnd (Cnode), Opnds); - end loop Inner; - - Expand_Concatenate (Cnode, Opnds); - - exit Outer when Cnode = N; - Cnode := Parent (Cnode); - end loop Outer; - end Expand_N_Op_Concat; - - ------------------------ - -- Expand_N_Op_Divide -- - ------------------------ - - procedure Expand_N_Op_Divide (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Lopnd : constant Node_Id := Left_Opnd (N); - Ropnd : constant Node_Id := Right_Opnd (N); - Ltyp : constant Entity_Id := Etype (Lopnd); - Rtyp : constant Entity_Id := Etype (Ropnd); - Typ : Entity_Id := Etype (N); - Rknow : constant Boolean := Is_Integer_Type (Typ) - and then - Compile_Time_Known_Value (Ropnd); - Rval : Uint; - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- Otherwise proceed with expansion of division - - if Rknow then - Rval := Expr_Value (Ropnd); - end if; - - -- N / 1 = N for integer types - - if Rknow and then Rval = Uint_1 then - Rewrite (N, Lopnd); - return; - end if; - - -- Convert x / 2 ** y to Shift_Right (x, y). Note that the fact that - -- Is_Power_Of_2_For_Shift is set means that we know that our left - -- operand is an unsigned integer, as required for this to work. - - if Nkind (Ropnd) = N_Op_Expon - and then Is_Power_Of_2_For_Shift (Ropnd) - - -- We cannot do this transformation in configurable run time mode if we - -- have 64-bit integers and long shifts are not available. - - and then - (Esize (Ltyp) <= 32 - or else Support_Long_Shifts_On_Target) - then - Rewrite (N, - Make_Op_Shift_Right (Loc, - Left_Opnd => Lopnd, - Right_Opnd => - Convert_To (Standard_Natural, Right_Opnd (Ropnd)))); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Do required fixup of universal fixed operation - - if Typ = Universal_Fixed then - Fixup_Universal_Fixed_Operation (N); - Typ := Etype (N); - end if; - - -- Divisions with fixed-point results - - if Is_Fixed_Point_Type (Typ) then - - -- No special processing if Treat_Fixed_As_Integer is set, since - -- from a semantic point of view such operations are simply integer - -- operations and will be treated that way. - - if not Treat_Fixed_As_Integer (N) then - if Is_Integer_Type (Rtyp) then - Expand_Divide_Fixed_By_Integer_Giving_Fixed (N); - else - Expand_Divide_Fixed_By_Fixed_Giving_Fixed (N); - end if; - end if; - - -- Other cases of division of fixed-point operands. Again we exclude the - -- case where Treat_Fixed_As_Integer is set. - - elsif (Is_Fixed_Point_Type (Ltyp) or else - Is_Fixed_Point_Type (Rtyp)) - and then not Treat_Fixed_As_Integer (N) - then - if Is_Integer_Type (Typ) then - Expand_Divide_Fixed_By_Fixed_Giving_Integer (N); - else - pragma Assert (Is_Floating_Point_Type (Typ)); - Expand_Divide_Fixed_By_Fixed_Giving_Float (N); - end if; - - -- Mixed-mode operations can appear in a non-static universal context, - -- in which case the integer argument must be converted explicitly. - - elsif Typ = Universal_Real - and then Is_Integer_Type (Rtyp) - then - Rewrite (Ropnd, - Convert_To (Universal_Real, Relocate_Node (Ropnd))); - - Analyze_And_Resolve (Ropnd, Universal_Real); - - elsif Typ = Universal_Real - and then Is_Integer_Type (Ltyp) - then - Rewrite (Lopnd, - Convert_To (Universal_Real, Relocate_Node (Lopnd))); - - Analyze_And_Resolve (Lopnd, Universal_Real); - - -- Non-fixed point cases, do integer zero divide and overflow checks - - elsif Is_Integer_Type (Typ) then - Apply_Divide_Checks (N); - - -- Deal with Vax_Float - - elsif Vax_Float (Typ) then - Expand_Vax_Arith (N); - return; - end if; - end Expand_N_Op_Divide; - - -------------------- - -- Expand_N_Op_Eq -- - -------------------- - - procedure Expand_N_Op_Eq (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Lhs : constant Node_Id := Left_Opnd (N); - Rhs : constant Node_Id := Right_Opnd (N); - Bodies : constant List_Id := New_List; - A_Typ : constant Entity_Id := Etype (Lhs); - - Typl : Entity_Id := A_Typ; - Op_Name : Entity_Id; - Prim : Elmt_Id; - - procedure Build_Equality_Call (Eq : Entity_Id); - -- If a constructed equality exists for the type or for its parent, - -- build and analyze call, adding conversions if the operation is - -- inherited. - - function Has_Unconstrained_UU_Component (Typ : Node_Id) return Boolean; - -- Determines whether a type has a subcomponent of an unconstrained - -- Unchecked_Union subtype. Typ is a record type. - - ------------------------- - -- Build_Equality_Call -- - ------------------------- - - procedure Build_Equality_Call (Eq : Entity_Id) is - Op_Type : constant Entity_Id := Etype (First_Formal (Eq)); - L_Exp : Node_Id := Relocate_Node (Lhs); - R_Exp : Node_Id := Relocate_Node (Rhs); - - begin - if Base_Type (Op_Type) /= Base_Type (A_Typ) - and then not Is_Class_Wide_Type (A_Typ) - then - L_Exp := OK_Convert_To (Op_Type, L_Exp); - R_Exp := OK_Convert_To (Op_Type, R_Exp); - end if; - - -- If we have an Unchecked_Union, we need to add the inferred - -- discriminant values as actuals in the function call. At this - -- point, the expansion has determined that both operands have - -- inferable discriminants. - - if Is_Unchecked_Union (Op_Type) then - declare - Lhs_Type : constant Node_Id := Etype (L_Exp); - Rhs_Type : constant Node_Id := Etype (R_Exp); - Lhs_Discr_Val : Node_Id; - Rhs_Discr_Val : Node_Id; - - begin - -- Per-object constrained selected components require special - -- attention. If the enclosing scope of the component is an - -- Unchecked_Union, we cannot reference its discriminants - -- directly. This is why we use the two extra parameters of - -- the equality function of the enclosing Unchecked_Union. - - -- type UU_Type (Discr : Integer := 0) is - -- . . . - -- end record; - -- pragma Unchecked_Union (UU_Type); - - -- 1. Unchecked_Union enclosing record: - - -- type Enclosing_UU_Type (Discr : Integer := 0) is record - -- . . . - -- Comp : UU_Type (Discr); - -- . . . - -- end Enclosing_UU_Type; - -- pragma Unchecked_Union (Enclosing_UU_Type); - - -- Obj1 : Enclosing_UU_Type; - -- Obj2 : Enclosing_UU_Type (1); - - -- [. . .] Obj1 = Obj2 [. . .] - - -- Generated code: - - -- if not (uu_typeEQ (obj1.comp, obj2.comp, a, b)) then - - -- A and B are the formal parameters of the equality function - -- of Enclosing_UU_Type. The function always has two extra - -- formals to capture the inferred discriminant values. - - -- 2. Non-Unchecked_Union enclosing record: - - -- type - -- Enclosing_Non_UU_Type (Discr : Integer := 0) - -- is record - -- . . . - -- Comp : UU_Type (Discr); - -- . . . - -- end Enclosing_Non_UU_Type; - - -- Obj1 : Enclosing_Non_UU_Type; - -- Obj2 : Enclosing_Non_UU_Type (1); - - -- ... Obj1 = Obj2 ... - - -- Generated code: - - -- if not (uu_typeEQ (obj1.comp, obj2.comp, - -- obj1.discr, obj2.discr)) then - - -- In this case we can directly reference the discriminants of - -- the enclosing record. - - -- Lhs of equality - - if Nkind (Lhs) = N_Selected_Component - and then Has_Per_Object_Constraint - (Entity (Selector_Name (Lhs))) - then - -- Enclosing record is an Unchecked_Union, use formal A - - if Is_Unchecked_Union - (Scope (Entity (Selector_Name (Lhs)))) - then - Lhs_Discr_Val := Make_Identifier (Loc, Name_A); - - -- Enclosing record is of a non-Unchecked_Union type, it is - -- possible to reference the discriminant. - - else - Lhs_Discr_Val := - Make_Selected_Component (Loc, - Prefix => Prefix (Lhs), - Selector_Name => - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Lhs_Type), - Lhs_Type, - Stored_Constraint (Lhs_Type)))); - end if; - - -- Comment needed here ??? - - else - -- Infer the discriminant value - - Lhs_Discr_Val := - New_Copy - (Get_Discriminant_Value - (First_Discriminant (Lhs_Type), - Lhs_Type, - Stored_Constraint (Lhs_Type))); - end if; - - -- Rhs of equality - - if Nkind (Rhs) = N_Selected_Component - and then Has_Per_Object_Constraint - (Entity (Selector_Name (Rhs))) - then - if Is_Unchecked_Union - (Scope (Entity (Selector_Name (Rhs)))) - then - Rhs_Discr_Val := Make_Identifier (Loc, Name_B); - - else - Rhs_Discr_Val := - Make_Selected_Component (Loc, - Prefix => Prefix (Rhs), - Selector_Name => - New_Copy (Get_Discriminant_Value ( - First_Discriminant (Rhs_Type), - Rhs_Type, - Stored_Constraint (Rhs_Type)))); - - end if; - else - Rhs_Discr_Val := - New_Copy (Get_Discriminant_Value ( - First_Discriminant (Rhs_Type), - Rhs_Type, - Stored_Constraint (Rhs_Type))); - - end if; - - Rewrite (N, - Make_Function_Call (Loc, - Name => New_Reference_To (Eq, Loc), - Parameter_Associations => New_List ( - L_Exp, - R_Exp, - Lhs_Discr_Val, - Rhs_Discr_Val))); - end; - - -- Normal case, not an unchecked union - - else - Rewrite (N, - Make_Function_Call (Loc, - Name => New_Reference_To (Eq, Loc), - Parameter_Associations => New_List (L_Exp, R_Exp))); - end if; - - Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); - end Build_Equality_Call; - - ------------------------------------ - -- Has_Unconstrained_UU_Component -- - ------------------------------------ - - function Has_Unconstrained_UU_Component - (Typ : Node_Id) return Boolean - is - Tdef : constant Node_Id := - Type_Definition (Declaration_Node (Base_Type (Typ))); - Clist : Node_Id; - Vpart : Node_Id; - - function Component_Is_Unconstrained_UU - (Comp : Node_Id) return Boolean; - -- Determines whether the subtype of the component is an - -- unconstrained Unchecked_Union. - - function Variant_Is_Unconstrained_UU - (Variant : Node_Id) return Boolean; - -- Determines whether a component of the variant has an unconstrained - -- Unchecked_Union subtype. - - ----------------------------------- - -- Component_Is_Unconstrained_UU -- - ----------------------------------- - - function Component_Is_Unconstrained_UU - (Comp : Node_Id) return Boolean - is - begin - if Nkind (Comp) /= N_Component_Declaration then - return False; - end if; - - declare - Sindic : constant Node_Id := - Subtype_Indication (Component_Definition (Comp)); - - begin - -- Unconstrained nominal type. In the case of a constraint - -- present, the node kind would have been N_Subtype_Indication. - - if Nkind (Sindic) = N_Identifier then - return Is_Unchecked_Union (Base_Type (Etype (Sindic))); - end if; - - return False; - end; - end Component_Is_Unconstrained_UU; - - --------------------------------- - -- Variant_Is_Unconstrained_UU -- - --------------------------------- - - function Variant_Is_Unconstrained_UU - (Variant : Node_Id) return Boolean - is - Clist : constant Node_Id := Component_List (Variant); - - begin - if Is_Empty_List (Component_Items (Clist)) then - return False; - end if; - - -- We only need to test one component - - declare - Comp : Node_Id := First (Component_Items (Clist)); - - begin - while Present (Comp) loop - if Component_Is_Unconstrained_UU (Comp) then - return True; - end if; - - Next (Comp); - end loop; - end; - - -- None of the components withing the variant were of - -- unconstrained Unchecked_Union type. - - return False; - end Variant_Is_Unconstrained_UU; - - -- Start of processing for Has_Unconstrained_UU_Component - - begin - if Null_Present (Tdef) then - return False; - end if; - - Clist := Component_List (Tdef); - Vpart := Variant_Part (Clist); - - -- Inspect available components - - if Present (Component_Items (Clist)) then - declare - Comp : Node_Id := First (Component_Items (Clist)); - - begin - while Present (Comp) loop - - -- One component is sufficient - - if Component_Is_Unconstrained_UU (Comp) then - return True; - end if; - - Next (Comp); - end loop; - end; - end if; - - -- Inspect available components withing variants - - if Present (Vpart) then - declare - Variant : Node_Id := First (Variants (Vpart)); - - begin - while Present (Variant) loop - - -- One component within a variant is sufficient - - if Variant_Is_Unconstrained_UU (Variant) then - return True; - end if; - - Next (Variant); - end loop; - end; - end if; - - -- Neither the available components, nor the components inside the - -- variant parts were of an unconstrained Unchecked_Union subtype. - - return False; - end Has_Unconstrained_UU_Component; - - -- Start of processing for Expand_N_Op_Eq - - begin - Binary_Op_Validity_Checks (N); - - -- Deal with private types - - if Ekind (Typl) = E_Private_Type then - Typl := Underlying_Type (Typl); - elsif Ekind (Typl) = E_Private_Subtype then - Typl := Underlying_Type (Base_Type (Typl)); - else - null; - end if; - - -- It may happen in error situations that the underlying type is not - -- set. The error will be detected later, here we just defend the - -- expander code. - - if No (Typl) then - return; - end if; - - Typl := Base_Type (Typl); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that - -- means we no longer have a comparison operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Eq then - return; - end if; - - -- Boolean types (requiring handling of non-standard case) - - if Is_Boolean_Type (Typl) then - Adjust_Condition (Left_Opnd (N)); - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - - -- Array types - - elsif Is_Array_Type (Typl) then - - -- If we are doing full validity checking, and it is possible for the - -- array elements to be invalid then expand out array comparisons to - -- make sure that we check the array elements. - - if Validity_Check_Operands - and then not Is_Known_Valid (Component_Type (Typl)) - then - declare - Save_Force_Validity_Checks : constant Boolean := - Force_Validity_Checks; - begin - Force_Validity_Checks := True; - Rewrite (N, - Expand_Array_Equality - (N, - Relocate_Node (Lhs), - Relocate_Node (Rhs), - Bodies, - Typl)); - Insert_Actions (N, Bodies); - Analyze_And_Resolve (N, Standard_Boolean); - Force_Validity_Checks := Save_Force_Validity_Checks; - end; - - -- Packed case where both operands are known aligned - - elsif Is_Bit_Packed_Array (Typl) - and then not Is_Possibly_Unaligned_Object (Lhs) - and then not Is_Possibly_Unaligned_Object (Rhs) - then - Expand_Packed_Eq (N); - - -- Where the component type is elementary we can use a block bit - -- comparison (if supported on the target) exception in the case - -- of floating-point (negative zero issues require element by - -- element comparison), and atomic types (where we must be sure - -- to load elements independently) and possibly unaligned arrays. - - elsif Is_Elementary_Type (Component_Type (Typl)) - and then not Is_Floating_Point_Type (Component_Type (Typl)) - and then not Is_Atomic (Component_Type (Typl)) - and then not Is_Possibly_Unaligned_Object (Lhs) - and then not Is_Possibly_Unaligned_Object (Rhs) - and then Support_Composite_Compare_On_Target - then - null; - - -- For composite and floating-point cases, expand equality loop to - -- make sure of using proper comparisons for tagged types, and - -- correctly handling the floating-point case. - - else - Rewrite (N, - Expand_Array_Equality - (N, - Relocate_Node (Lhs), - Relocate_Node (Rhs), - Bodies, - Typl)); - Insert_Actions (N, Bodies, Suppress => All_Checks); - Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); - end if; - - -- Record Types - - elsif Is_Record_Type (Typl) then - - -- For tagged types, use the primitive "=" - - if Is_Tagged_Type (Typl) then - - -- No need to do anything else compiling under restriction - -- No_Dispatching_Calls. During the semantic analysis we - -- already notified such violation. - - if Restriction_Active (No_Dispatching_Calls) then - return; - end if; - - -- If this is derived from an untagged private type completed with - -- a tagged type, it does not have a full view, so we use the - -- primitive operations of the private type. This check should no - -- longer be necessary when these types get their full views??? - - if Is_Private_Type (A_Typ) - and then not Is_Tagged_Type (A_Typ) - and then Is_Derived_Type (A_Typ) - and then No (Full_View (A_Typ)) - then - -- Search for equality operation, checking that the operands - -- have the same type. Note that we must find a matching entry, - -- or something is very wrong! - - Prim := First_Elmt (Collect_Primitive_Operations (A_Typ)); - - while Present (Prim) loop - exit when Chars (Node (Prim)) = Name_Op_Eq - and then Etype (First_Formal (Node (Prim))) = - Etype (Next_Formal (First_Formal (Node (Prim)))) - and then - Base_Type (Etype (Node (Prim))) = Standard_Boolean; - - Next_Elmt (Prim); - end loop; - - pragma Assert (Present (Prim)); - Op_Name := Node (Prim); - - -- Find the type's predefined equality or an overriding - -- user- defined equality. The reason for not simply calling - -- Find_Prim_Op here is that there may be a user-defined - -- overloaded equality op that precedes the equality that we want, - -- so we have to explicitly search (e.g., there could be an - -- equality with two different parameter types). - - else - if Is_Class_Wide_Type (Typl) then - Typl := Root_Type (Typl); - end if; - - Prim := First_Elmt (Primitive_Operations (Typl)); - while Present (Prim) loop - exit when Chars (Node (Prim)) = Name_Op_Eq - and then Etype (First_Formal (Node (Prim))) = - Etype (Next_Formal (First_Formal (Node (Prim)))) - and then - Base_Type (Etype (Node (Prim))) = Standard_Boolean; - - Next_Elmt (Prim); - end loop; - - pragma Assert (Present (Prim)); - Op_Name := Node (Prim); - end if; - - Build_Equality_Call (Op_Name); - - -- Ada 2005 (AI-216): Program_Error is raised when evaluating the - -- predefined equality operator for a type which has a subcomponent - -- of an Unchecked_Union type whose nominal subtype is unconstrained. - - elsif Has_Unconstrained_UU_Component (Typl) then - Insert_Action (N, - Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction)); - - -- Prevent Gigi from generating incorrect code by rewriting the - -- equality as a standard False. (is this documented somewhere???) - - Rewrite (N, - New_Occurrence_Of (Standard_False, Loc)); - - elsif Is_Unchecked_Union (Typl) then - - -- If we can infer the discriminants of the operands, we make a - -- call to the TSS equality function. - - if Has_Inferable_Discriminants (Lhs) - and then - Has_Inferable_Discriminants (Rhs) - then - Build_Equality_Call - (TSS (Root_Type (Typl), TSS_Composite_Equality)); - - else - -- Ada 2005 (AI-216): Program_Error is raised when evaluating - -- the predefined equality operator for an Unchecked_Union type - -- if either of the operands lack inferable discriminants. - - Insert_Action (N, - Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction)); - - -- Prevent Gigi from generating incorrect code by rewriting - -- the equality as a standard False (documented where???). - - Rewrite (N, - New_Occurrence_Of (Standard_False, Loc)); - - end if; - - -- If a type support function is present (for complex cases), use it - - elsif Present (TSS (Root_Type (Typl), TSS_Composite_Equality)) then - Build_Equality_Call - (TSS (Root_Type (Typl), TSS_Composite_Equality)); - - -- Otherwise expand the component by component equality. Note that - -- we never use block-bit comparisons for records, because of the - -- problems with gaps. The backend will often be able to recombine - -- the separate comparisons that we generate here. - - else - Remove_Side_Effects (Lhs); - Remove_Side_Effects (Rhs); - Rewrite (N, - Expand_Record_Equality (N, Typl, Lhs, Rhs, Bodies)); - - Insert_Actions (N, Bodies, Suppress => All_Checks); - Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); - end if; - end if; - - -- Test if result is known at compile time - - Rewrite_Comparison (N); - - -- If we still have comparison for Vax_Float, process it - - if Vax_Float (Typl) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Eq; - - ----------------------- - -- Expand_N_Op_Expon -- - ----------------------- - - procedure Expand_N_Op_Expon (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Rtyp : constant Entity_Id := Root_Type (Typ); - Base : constant Node_Id := Relocate_Node (Left_Opnd (N)); - Bastyp : constant Node_Id := Etype (Base); - Exp : constant Node_Id := Relocate_Node (Right_Opnd (N)); - Exptyp : constant Entity_Id := Etype (Exp); - Ovflo : constant Boolean := Do_Overflow_Check (N); - Expv : Uint; - Temp : Node_Id; - Rent : RE_Id; - Ent : Entity_Id; - Etyp : Entity_Id; - Xnode : Node_Id; - - begin - Binary_Op_Validity_Checks (N); - - -- CodePeer and GNATprove want to see the unexpanded N_Op_Expon node - - if CodePeer_Mode or Alfa_Mode then - return; - end if; - - -- If either operand is of a private type, then we have the use of an - -- intrinsic operator, and we get rid of the privateness, by using root - -- types of underlying types for the actual operation. Otherwise the - -- private types will cause trouble if we expand multiplications or - -- shifts etc. We also do this transformation if the result type is - -- different from the base type. - - if Is_Private_Type (Etype (Base)) - or else Is_Private_Type (Typ) - or else Is_Private_Type (Exptyp) - or else Rtyp /= Root_Type (Bastyp) - then - declare - Bt : constant Entity_Id := Root_Type (Underlying_Type (Bastyp)); - Et : constant Entity_Id := Root_Type (Underlying_Type (Exptyp)); - - begin - Rewrite (N, - Unchecked_Convert_To (Typ, - Make_Op_Expon (Loc, - Left_Opnd => Unchecked_Convert_To (Bt, Base), - Right_Opnd => Unchecked_Convert_To (Et, Exp)))); - Analyze_And_Resolve (N, Typ); - return; - end; - end if; - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- Test for case of known right argument where we can replace the - -- exponentiation by an equivalent expression using multiplication. - - if Compile_Time_Known_Value (Exp) then - Expv := Expr_Value (Exp); - - -- We only fold small non-negative exponents. You might think we - -- could fold small negative exponents for the real case, but we - -- can't because we are required to raise Constraint_Error for - -- the case of 0.0 ** (negative) even if Machine_Overflows = False. - -- See ACVC test C4A012B. - - if Expv >= 0 and then Expv <= 4 then - - -- X ** 0 = 1 (or 1.0) - - if Expv = 0 then - - -- Call Remove_Side_Effects to ensure that any side effects - -- in the ignored left operand (in particular function calls - -- to user defined functions) are properly executed. - - Remove_Side_Effects (Base); - - if Ekind (Typ) in Integer_Kind then - Xnode := Make_Integer_Literal (Loc, Intval => 1); - else - Xnode := Make_Real_Literal (Loc, Ureal_1); - end if; - - -- X ** 1 = X - - elsif Expv = 1 then - Xnode := Base; - - -- X ** 2 = X * X - - elsif Expv = 2 then - Xnode := - Make_Op_Multiply (Loc, - Left_Opnd => Duplicate_Subexpr (Base), - Right_Opnd => Duplicate_Subexpr_No_Checks (Base)); - - -- X ** 3 = X * X * X - - elsif Expv = 3 then - Xnode := - Make_Op_Multiply (Loc, - Left_Opnd => - Make_Op_Multiply (Loc, - Left_Opnd => Duplicate_Subexpr (Base), - Right_Opnd => Duplicate_Subexpr_No_Checks (Base)), - Right_Opnd => Duplicate_Subexpr_No_Checks (Base)); - - -- X ** 4 -> - - -- do - -- En : constant base'type := base * base; - -- in - -- En * En - - else - pragma Assert (Expv = 4); - Temp := Make_Temporary (Loc, 'E', Base); - - Xnode := - Make_Expression_With_Actions (Loc, - Actions => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Constant_Present => True, - Object_Definition => New_Reference_To (Typ, Loc), - Expression => - Make_Op_Multiply (Loc, - Left_Opnd => - Duplicate_Subexpr (Base), - Right_Opnd => - Duplicate_Subexpr_No_Checks (Base)))), - - Expression => - Make_Op_Multiply (Loc, - Left_Opnd => New_Reference_To (Temp, Loc), - Right_Opnd => New_Reference_To (Temp, Loc))); - end if; - - Rewrite (N, Xnode); - Analyze_And_Resolve (N, Typ); - return; - end if; - end if; - - -- Case of (2 ** expression) appearing as an argument of an integer - -- multiplication, or as the right argument of a division of a non- - -- negative integer. In such cases we leave the node untouched, setting - -- the flag Is_Natural_Power_Of_2_for_Shift set, then the expansion - -- of the higher level node converts it into a shift. - - -- Another case is 2 ** N in any other context. We simply convert - -- this to 1 * 2 ** N, and then the above transformation applies. - - -- Note: this transformation is not applicable for a modular type with - -- a non-binary modulus in the multiplication case, since we get a wrong - -- result if the shift causes an overflow before the modular reduction. - - if Nkind (Base) = N_Integer_Literal - and then Intval (Base) = 2 - and then Is_Integer_Type (Root_Type (Exptyp)) - and then Esize (Root_Type (Exptyp)) <= Esize (Standard_Integer) - and then Is_Unsigned_Type (Exptyp) - and then not Ovflo - then - -- First the multiply and divide cases - - if Nkind_In (Parent (N), N_Op_Divide, N_Op_Multiply) then - declare - P : constant Node_Id := Parent (N); - L : constant Node_Id := Left_Opnd (P); - R : constant Node_Id := Right_Opnd (P); - - begin - if (Nkind (P) = N_Op_Multiply - and then not Non_Binary_Modulus (Typ) - and then - ((Is_Integer_Type (Etype (L)) and then R = N) - or else - (Is_Integer_Type (Etype (R)) and then L = N)) - and then not Do_Overflow_Check (P)) - or else - (Nkind (P) = N_Op_Divide - and then Is_Integer_Type (Etype (L)) - and then Is_Unsigned_Type (Etype (L)) - and then R = N - and then not Do_Overflow_Check (P)) - then - Set_Is_Power_Of_2_For_Shift (N); - return; - end if; - end; - - -- Now the other cases - - elsif not Non_Binary_Modulus (Typ) then - Rewrite (N, - Make_Op_Multiply (Loc, - Left_Opnd => Make_Integer_Literal (Loc, 1), - Right_Opnd => Relocate_Node (N))); - Analyze_And_Resolve (N, Typ); - return; - end if; - end if; - - -- Fall through if exponentiation must be done using a runtime routine - - -- First deal with modular case - - if Is_Modular_Integer_Type (Rtyp) then - - -- Non-binary case, we call the special exponentiation routine for - -- the non-binary case, converting the argument to Long_Long_Integer - -- and passing the modulus value. Then the result is converted back - -- to the base type. - - if Non_Binary_Modulus (Rtyp) then - Rewrite (N, - Convert_To (Typ, - Make_Function_Call (Loc, - Name => New_Reference_To (RTE (RE_Exp_Modular), Loc), - Parameter_Associations => New_List ( - Convert_To (Standard_Integer, Base), - Make_Integer_Literal (Loc, Modulus (Rtyp)), - Exp)))); - - -- Binary case, in this case, we call one of two routines, either the - -- unsigned integer case, or the unsigned long long integer case, - -- with a final "and" operation to do the required mod. - - else - if UI_To_Int (Esize (Rtyp)) <= Standard_Integer_Size then - Ent := RTE (RE_Exp_Unsigned); - else - Ent := RTE (RE_Exp_Long_Long_Unsigned); - end if; - - Rewrite (N, - Convert_To (Typ, - Make_Op_And (Loc, - Left_Opnd => - Make_Function_Call (Loc, - Name => New_Reference_To (Ent, Loc), - Parameter_Associations => New_List ( - Convert_To (Etype (First_Formal (Ent)), Base), - Exp)), - Right_Opnd => - Make_Integer_Literal (Loc, Modulus (Rtyp) - 1)))); - - end if; - - -- Common exit point for modular type case - - Analyze_And_Resolve (N, Typ); - return; - - -- Signed integer cases, done using either Integer or Long_Long_Integer. - -- It is not worth having routines for Short_[Short_]Integer, since for - -- most machines it would not help, and it would generate more code that - -- might need certification when a certified run time is required. - - -- In the integer cases, we have two routines, one for when overflow - -- checks are required, and one when they are not required, since there - -- is a real gain in omitting checks on many machines. - - elsif Rtyp = Base_Type (Standard_Long_Long_Integer) - or else (Rtyp = Base_Type (Standard_Long_Integer) - and then - Esize (Standard_Long_Integer) > Esize (Standard_Integer)) - or else (Rtyp = Universal_Integer) - then - Etyp := Standard_Long_Long_Integer; - - if Ovflo then - Rent := RE_Exp_Long_Long_Integer; - else - Rent := RE_Exn_Long_Long_Integer; - end if; - - elsif Is_Signed_Integer_Type (Rtyp) then - Etyp := Standard_Integer; - - if Ovflo then - Rent := RE_Exp_Integer; - else - Rent := RE_Exn_Integer; - end if; - - -- Floating-point cases, always done using Long_Long_Float. We do not - -- need separate routines for the overflow case here, since in the case - -- of floating-point, we generate infinities anyway as a rule (either - -- that or we automatically trap overflow), and if there is an infinity - -- generated and a range check is required, the check will fail anyway. - - else - pragma Assert (Is_Floating_Point_Type (Rtyp)); - Etyp := Standard_Long_Long_Float; - Rent := RE_Exn_Long_Long_Float; - end if; - - -- Common processing for integer cases and floating-point cases. - -- If we are in the right type, we can call runtime routine directly - - if Typ = Etyp - and then Rtyp /= Universal_Integer - and then Rtyp /= Universal_Real - then - Rewrite (N, - Make_Function_Call (Loc, - Name => New_Reference_To (RTE (Rent), Loc), - Parameter_Associations => New_List (Base, Exp))); - - -- Otherwise we have to introduce conversions (conversions are also - -- required in the universal cases, since the runtime routine is - -- typed using one of the standard types). - - else - Rewrite (N, - Convert_To (Typ, - Make_Function_Call (Loc, - Name => New_Reference_To (RTE (Rent), Loc), - Parameter_Associations => New_List ( - Convert_To (Etyp, Base), - Exp)))); - end if; - - Analyze_And_Resolve (N, Typ); - return; - - exception - when RE_Not_Available => - return; - end Expand_N_Op_Expon; - - -------------------- - -- Expand_N_Op_Ge -- - -------------------- - - procedure Expand_N_Op_Ge (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - Op1 : constant Node_Id := Left_Opnd (N); - Op2 : constant Node_Id := Right_Opnd (N); - Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); - - begin - Binary_Op_Validity_Checks (N); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that - -- means we no longer have a comparison operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Ge then - return; - end if; - - -- Array type case - - if Is_Array_Type (Typ1) then - Expand_Array_Comparison (N); - return; - end if; - - -- Deal with boolean operands - - if Is_Boolean_Type (Typ1) then - Adjust_Condition (Op1); - Adjust_Condition (Op2); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - end if; - - Rewrite_Comparison (N); - - -- If we still have comparison, and Vax_Float type, process it - - if Vax_Float (Typ1) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Ge; - - -------------------- - -- Expand_N_Op_Gt -- - -------------------- - - procedure Expand_N_Op_Gt (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - Op1 : constant Node_Id := Left_Opnd (N); - Op2 : constant Node_Id := Right_Opnd (N); - Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); - - begin - Binary_Op_Validity_Checks (N); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that - -- means we no longer have a comparison operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Gt then - return; - end if; - - -- Deal with array type operands - - if Is_Array_Type (Typ1) then - Expand_Array_Comparison (N); - return; - end if; - - -- Deal with boolean type operands - - if Is_Boolean_Type (Typ1) then - Adjust_Condition (Op1); - Adjust_Condition (Op2); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - end if; - - Rewrite_Comparison (N); - - -- If we still have comparison, and Vax_Float type, process it - - if Vax_Float (Typ1) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Gt; - - -------------------- - -- Expand_N_Op_Le -- - -------------------- - - procedure Expand_N_Op_Le (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - Op1 : constant Node_Id := Left_Opnd (N); - Op2 : constant Node_Id := Right_Opnd (N); - Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); - - begin - Binary_Op_Validity_Checks (N); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that - -- means we no longer have a comparison operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Le then - return; - end if; - - -- Deal with array type operands - - if Is_Array_Type (Typ1) then - Expand_Array_Comparison (N); - return; - end if; - - -- Deal with Boolean type operands - - if Is_Boolean_Type (Typ1) then - Adjust_Condition (Op1); - Adjust_Condition (Op2); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - end if; - - Rewrite_Comparison (N); - - -- If we still have comparison, and Vax_Float type, process it - - if Vax_Float (Typ1) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Le; - - -------------------- - -- Expand_N_Op_Lt -- - -------------------- - - procedure Expand_N_Op_Lt (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - Op1 : constant Node_Id := Left_Opnd (N); - Op2 : constant Node_Id := Right_Opnd (N); - Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); - - begin - Binary_Op_Validity_Checks (N); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that - -- means we no longer have a comparison operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Lt then - return; - end if; - - -- Deal with array type operands - - if Is_Array_Type (Typ1) then - Expand_Array_Comparison (N); - return; - end if; - - -- Deal with Boolean type operands - - if Is_Boolean_Type (Typ1) then - Adjust_Condition (Op1); - Adjust_Condition (Op2); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - end if; - - Rewrite_Comparison (N); - - -- If we still have comparison, and Vax_Float type, process it - - if Vax_Float (Typ1) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Lt; - - ----------------------- - -- Expand_N_Op_Minus -- - ----------------------- - - procedure Expand_N_Op_Minus (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - - begin - Unary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - if not Backend_Overflow_Checks_On_Target - and then Is_Signed_Integer_Type (Etype (N)) - and then Do_Overflow_Check (N) - then - -- Software overflow checking expands -expr into (0 - expr) - - Rewrite (N, - Make_Op_Subtract (Loc, - Left_Opnd => Make_Integer_Literal (Loc, 0), - Right_Opnd => Right_Opnd (N))); - - Analyze_And_Resolve (N, Typ); - - -- Vax floating-point types case - - elsif Vax_Float (Etype (N)) then - Expand_Vax_Arith (N); - end if; - end Expand_N_Op_Minus; - - --------------------- - -- Expand_N_Op_Mod -- - --------------------- - - procedure Expand_N_Op_Mod (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - DDC : constant Boolean := Do_Division_Check (N); - - Left : Node_Id; - Right : Node_Id; - - LLB : Uint; - Llo : Uint; - Lhi : Uint; - LOK : Boolean; - Rlo : Uint; - Rhi : Uint; - ROK : Boolean; - - pragma Warnings (Off, Lhi); - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - if Is_Integer_Type (Etype (N)) then - Apply_Divide_Checks (N); - - -- All done if we don't have a MOD any more, which can happen as a - -- result of overflow expansion in MINIMIZED or ELIMINATED modes. - - if Nkind (N) /= N_Op_Mod then - return; - end if; - end if; - - -- Proceed with expansion of mod operator - - Left := Left_Opnd (N); - Right := Right_Opnd (N); - - Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); - Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); - - -- Convert mod to rem if operands are known non-negative. We do this - -- since it is quite likely that this will improve the quality of code, - -- (the operation now corresponds to the hardware remainder), and it - -- does not seem likely that it could be harmful. - - if LOK and then Llo >= 0 - and then - ROK and then Rlo >= 0 - then - Rewrite (N, - Make_Op_Rem (Sloc (N), - Left_Opnd => Left_Opnd (N), - Right_Opnd => Right_Opnd (N))); - - -- Instead of reanalyzing the node we do the analysis manually. This - -- avoids anomalies when the replacement is done in an instance and - -- is epsilon more efficient. - - Set_Entity (N, Standard_Entity (S_Op_Rem)); - Set_Etype (N, Typ); - Set_Do_Division_Check (N, DDC); - Expand_N_Op_Rem (N); - Set_Analyzed (N); - - -- Otherwise, normal mod processing - - else - -- Apply optimization x mod 1 = 0. We don't really need that with - -- gcc, but it is useful with other back ends (e.g. AAMP), and is - -- certainly harmless. - - if Is_Integer_Type (Etype (N)) - and then Compile_Time_Known_Value (Right) - and then Expr_Value (Right) = Uint_1 - then - -- Call Remove_Side_Effects to ensure that any side effects in - -- the ignored left operand (in particular function calls to - -- user defined functions) are properly executed. - - Remove_Side_Effects (Left); - - Rewrite (N, Make_Integer_Literal (Loc, 0)); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Deal with annoying case of largest negative number remainder - -- minus one. Gigi may not handle this case correctly, because - -- on some targets, the mod value is computed using a divide - -- instruction which gives an overflow trap for this case. - - -- It would be a bit more efficient to figure out which targets - -- this is really needed for, but in practice it is reasonable - -- to do the following special check in all cases, since it means - -- we get a clearer message, and also the overhead is minimal given - -- that division is expensive in any case. - - -- In fact the check is quite easy, if the right operand is -1, then - -- the mod value is always 0, and we can just ignore the left operand - -- completely in this case. - - -- This only applies if we still have a mod operator. Skip if we - -- have already rewritten this (e.g. in the case of eliminated - -- overflow checks which have driven us into bignum mode). - - if Nkind (N) = N_Op_Mod then - - -- The operand type may be private (e.g. in the expansion of an - -- intrinsic operation) so we must use the underlying type to get - -- the bounds, and convert the literals explicitly. - - LLB := - Expr_Value - (Type_Low_Bound (Base_Type (Underlying_Type (Etype (Left))))); - - if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) - and then - ((not LOK) or else (Llo = LLB)) - then - Rewrite (N, - Make_If_Expression (Loc, - Expressions => New_List ( - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Right), - Right_Opnd => - Unchecked_Convert_To (Typ, - Make_Integer_Literal (Loc, -1))), - Unchecked_Convert_To (Typ, - Make_Integer_Literal (Loc, Uint_0)), - Relocate_Node (N)))); - - Set_Analyzed (Next (Next (First (Expressions (N))))); - Analyze_And_Resolve (N, Typ); - end if; - end if; - end if; - end Expand_N_Op_Mod; - - -------------------------- - -- Expand_N_Op_Multiply -- - -------------------------- - - procedure Expand_N_Op_Multiply (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Lop : constant Node_Id := Left_Opnd (N); - Rop : constant Node_Id := Right_Opnd (N); - - Lp2 : constant Boolean := - Nkind (Lop) = N_Op_Expon - and then Is_Power_Of_2_For_Shift (Lop); - - Rp2 : constant Boolean := - Nkind (Rop) = N_Op_Expon - and then Is_Power_Of_2_For_Shift (Rop); - - Ltyp : constant Entity_Id := Etype (Lop); - Rtyp : constant Entity_Id := Etype (Rop); - Typ : Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- Special optimizations for integer types - - if Is_Integer_Type (Typ) then - - -- N * 0 = 0 for integer types - - if Compile_Time_Known_Value (Rop) - and then Expr_Value (Rop) = Uint_0 - then - -- Call Remove_Side_Effects to ensure that any side effects in - -- the ignored left operand (in particular function calls to - -- user defined functions) are properly executed. - - Remove_Side_Effects (Lop); - - Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Similar handling for 0 * N = 0 - - if Compile_Time_Known_Value (Lop) - and then Expr_Value (Lop) = Uint_0 - then - Remove_Side_Effects (Rop); - Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- N * 1 = 1 * N = N for integer types - - -- This optimisation is not done if we are going to - -- rewrite the product 1 * 2 ** N to a shift. - - if Compile_Time_Known_Value (Rop) - and then Expr_Value (Rop) = Uint_1 - and then not Lp2 - then - Rewrite (N, Lop); - return; - - elsif Compile_Time_Known_Value (Lop) - and then Expr_Value (Lop) = Uint_1 - and then not Rp2 - then - Rewrite (N, Rop); - return; - end if; - end if; - - -- Convert x * 2 ** y to Shift_Left (x, y). Note that the fact that - -- Is_Power_Of_2_For_Shift is set means that we know that our left - -- operand is an integer, as required for this to work. - - if Rp2 then - if Lp2 then - - -- Convert 2 ** A * 2 ** B into 2 ** (A + B) - - Rewrite (N, - Make_Op_Expon (Loc, - Left_Opnd => Make_Integer_Literal (Loc, 2), - Right_Opnd => - Make_Op_Add (Loc, - Left_Opnd => Right_Opnd (Lop), - Right_Opnd => Right_Opnd (Rop)))); - Analyze_And_Resolve (N, Typ); - return; - - else - Rewrite (N, - Make_Op_Shift_Left (Loc, - Left_Opnd => Lop, - Right_Opnd => - Convert_To (Standard_Natural, Right_Opnd (Rop)))); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Same processing for the operands the other way round - - elsif Lp2 then - Rewrite (N, - Make_Op_Shift_Left (Loc, - Left_Opnd => Rop, - Right_Opnd => - Convert_To (Standard_Natural, Right_Opnd (Lop)))); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Do required fixup of universal fixed operation - - if Typ = Universal_Fixed then - Fixup_Universal_Fixed_Operation (N); - Typ := Etype (N); - end if; - - -- Multiplications with fixed-point results - - if Is_Fixed_Point_Type (Typ) then - - -- No special processing if Treat_Fixed_As_Integer is set, since from - -- a semantic point of view such operations are simply integer - -- operations and will be treated that way. - - if not Treat_Fixed_As_Integer (N) then - - -- Case of fixed * integer => fixed - - if Is_Integer_Type (Rtyp) then - Expand_Multiply_Fixed_By_Integer_Giving_Fixed (N); - - -- Case of integer * fixed => fixed - - elsif Is_Integer_Type (Ltyp) then - Expand_Multiply_Integer_By_Fixed_Giving_Fixed (N); - - -- Case of fixed * fixed => fixed - - else - Expand_Multiply_Fixed_By_Fixed_Giving_Fixed (N); - end if; - end if; - - -- Other cases of multiplication of fixed-point operands. Again we - -- exclude the cases where Treat_Fixed_As_Integer flag is set. - - elsif (Is_Fixed_Point_Type (Ltyp) or else Is_Fixed_Point_Type (Rtyp)) - and then not Treat_Fixed_As_Integer (N) - then - if Is_Integer_Type (Typ) then - Expand_Multiply_Fixed_By_Fixed_Giving_Integer (N); - else - pragma Assert (Is_Floating_Point_Type (Typ)); - Expand_Multiply_Fixed_By_Fixed_Giving_Float (N); - end if; - - -- Mixed-mode operations can appear in a non-static universal context, - -- in which case the integer argument must be converted explicitly. - - elsif Typ = Universal_Real - and then Is_Integer_Type (Rtyp) - then - Rewrite (Rop, Convert_To (Universal_Real, Relocate_Node (Rop))); - - Analyze_And_Resolve (Rop, Universal_Real); - - elsif Typ = Universal_Real - and then Is_Integer_Type (Ltyp) - then - Rewrite (Lop, Convert_To (Universal_Real, Relocate_Node (Lop))); - - Analyze_And_Resolve (Lop, Universal_Real); - - -- Non-fixed point cases, check software overflow checking required - - elsif Is_Signed_Integer_Type (Etype (N)) then - Apply_Arithmetic_Overflow_Check (N); - - -- Deal with VAX float case - - elsif Vax_Float (Typ) then - Expand_Vax_Arith (N); - return; - end if; - end Expand_N_Op_Multiply; - - -------------------- - -- Expand_N_Op_Ne -- - -------------------- - - procedure Expand_N_Op_Ne (N : Node_Id) is - Typ : constant Entity_Id := Etype (Left_Opnd (N)); - - begin - -- Case of elementary type with standard operator - - if Is_Elementary_Type (Typ) - and then Sloc (Entity (N)) = Standard_Location - then - Binary_Op_Validity_Checks (N); - - -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if - -- means we no longer have a /= operation, we are all done. - - Expand_Compare_Minimize_Eliminate_Overflow (N); - - if Nkind (N) /= N_Op_Ne then - return; - end if; - - -- Boolean types (requiring handling of non-standard case) - - if Is_Boolean_Type (Typ) then - Adjust_Condition (Left_Opnd (N)); - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - end if; - - Rewrite_Comparison (N); - - -- If we still have comparison for Vax_Float, process it - - if Vax_Float (Typ) and then Nkind (N) in N_Op_Compare then - Expand_Vax_Comparison (N); - return; - end if; - - -- For all cases other than elementary types, we rewrite node as the - -- negation of an equality operation, and reanalyze. The equality to be - -- used is defined in the same scope and has the same signature. This - -- signature must be set explicitly since in an instance it may not have - -- the same visibility as in the generic unit. This avoids duplicating - -- or factoring the complex code for record/array equality tests etc. - - else - declare - Loc : constant Source_Ptr := Sloc (N); - Neg : Node_Id; - Ne : constant Entity_Id := Entity (N); - - begin - Binary_Op_Validity_Checks (N); - - Neg := - Make_Op_Not (Loc, - Right_Opnd => - Make_Op_Eq (Loc, - Left_Opnd => Left_Opnd (N), - Right_Opnd => Right_Opnd (N))); - Set_Paren_Count (Right_Opnd (Neg), 1); - - if Scope (Ne) /= Standard_Standard then - Set_Entity (Right_Opnd (Neg), Corresponding_Equality (Ne)); - end if; - - -- For navigation purposes, we want to treat the inequality as an - -- implicit reference to the corresponding equality. Preserve the - -- Comes_From_ source flag to generate proper Xref entries. - - Preserve_Comes_From_Source (Neg, N); - Preserve_Comes_From_Source (Right_Opnd (Neg), N); - Rewrite (N, Neg); - Analyze_And_Resolve (N, Standard_Boolean); - end; - end if; - - Optimize_Length_Comparison (N); - end Expand_N_Op_Ne; - - --------------------- - -- Expand_N_Op_Not -- - --------------------- - - -- If the argument is other than a Boolean array type, there is no special - -- expansion required, except for VMS operations on signed integers. - - -- For the packed case, we call the special routine in Exp_Pakd, except - -- that if the component size is greater than one, we use the standard - -- routine generating a gruesome loop (it is so peculiar to have packed - -- arrays with non-standard Boolean representations anyway, so it does not - -- matter that we do not handle this case efficiently). - - -- For the unpacked case (and for the special packed case where we have non - -- standard Booleans, as discussed above), we generate and insert into the - -- tree the following function definition: - - -- function Nnnn (A : arr) is - -- B : arr; - -- begin - -- for J in a'range loop - -- B (J) := not A (J); - -- end loop; - -- return B; - -- end Nnnn; - - -- Here arr is the actual subtype of the parameter (and hence always - -- constrained). Then we replace the not with a call to this function. - - procedure Expand_N_Op_Not (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Opnd : Node_Id; - Arr : Entity_Id; - A : Entity_Id; - B : Entity_Id; - J : Entity_Id; - A_J : Node_Id; - B_J : Node_Id; - - Func_Name : Entity_Id; - Loop_Statement : Node_Id; - - begin - Unary_Op_Validity_Checks (N); - - -- For boolean operand, deal with non-standard booleans - - if Is_Boolean_Type (Typ) then - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - return; - end if; - - -- For the VMS "not" on signed integer types, use conversion to and from - -- a predefined modular type. - - if Is_VMS_Operator (Entity (N)) then - declare - Rtyp : Entity_Id; - Utyp : Entity_Id; - - begin - -- If this is a derived type, retrieve original VMS type so that - -- the proper sized type is used for intermediate values. - - if Is_Derived_Type (Typ) then - Rtyp := First_Subtype (Etype (Typ)); - else - Rtyp := Typ; - end if; - - -- The proper unsigned type must have a size compatible with the - -- operand, to prevent misalignment. - - if RM_Size (Rtyp) <= 8 then - Utyp := RTE (RE_Unsigned_8); - - elsif RM_Size (Rtyp) <= 16 then - Utyp := RTE (RE_Unsigned_16); - - elsif RM_Size (Rtyp) = RM_Size (Standard_Unsigned) then - Utyp := RTE (RE_Unsigned_32); - - else - Utyp := RTE (RE_Long_Long_Unsigned); - end if; - - Rewrite (N, - Unchecked_Convert_To (Typ, - Make_Op_Not (Loc, - Unchecked_Convert_To (Utyp, Right_Opnd (N))))); - Analyze_And_Resolve (N, Typ); - return; - end; - end if; - - -- Only array types need any other processing - - if not Is_Array_Type (Typ) then - return; - end if; - - -- Case of array operand. If bit packed with a component size of 1, - -- handle it in Exp_Pakd if the operand is known to be aligned. - - if Is_Bit_Packed_Array (Typ) - and then Component_Size (Typ) = 1 - and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) - then - Expand_Packed_Not (N); - return; - end if; - - -- Case of array operand which is not bit-packed. If the context is - -- a safe assignment, call in-place operation, If context is a larger - -- boolean expression in the context of a safe assignment, expansion is - -- done by enclosing operation. - - Opnd := Relocate_Node (Right_Opnd (N)); - Convert_To_Actual_Subtype (Opnd); - Arr := Etype (Opnd); - Ensure_Defined (Arr, N); - Silly_Boolean_Array_Not_Test (N, Arr); - - if Nkind (Parent (N)) = N_Assignment_Statement then - if Safe_In_Place_Array_Op (Name (Parent (N)), N, Empty) then - Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); - return; - - -- Special case the negation of a binary operation - - elsif Nkind_In (Opnd, N_Op_And, N_Op_Or, N_Op_Xor) - and then Safe_In_Place_Array_Op - (Name (Parent (N)), Left_Opnd (Opnd), Right_Opnd (Opnd)) - then - Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); - return; - end if; - - elsif Nkind (Parent (N)) in N_Binary_Op - and then Nkind (Parent (Parent (N))) = N_Assignment_Statement - then - declare - Op1 : constant Node_Id := Left_Opnd (Parent (N)); - Op2 : constant Node_Id := Right_Opnd (Parent (N)); - Lhs : constant Node_Id := Name (Parent (Parent (N))); - - begin - if Safe_In_Place_Array_Op (Lhs, Op1, Op2) then - - -- (not A) op (not B) can be reduced to a single call - - if N = Op1 and then Nkind (Op2) = N_Op_Not then - return; - - elsif N = Op2 and then Nkind (Op1) = N_Op_Not then - return; - - -- A xor (not B) can also be special-cased - - elsif N = Op2 and then Nkind (Parent (N)) = N_Op_Xor then - return; - end if; - end if; - end; - end if; - - A := Make_Defining_Identifier (Loc, Name_uA); - B := Make_Defining_Identifier (Loc, Name_uB); - J := Make_Defining_Identifier (Loc, Name_uJ); - - A_J := - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (A, Loc), - Expressions => New_List (New_Reference_To (J, Loc))); - - B_J := - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (B, Loc), - Expressions => New_List (New_Reference_To (J, Loc))); - - Loop_Statement := - Make_Implicit_Loop_Statement (N, - Identifier => Empty, - - Iteration_Scheme => - Make_Iteration_Scheme (Loc, - Loop_Parameter_Specification => - Make_Loop_Parameter_Specification (Loc, - Defining_Identifier => J, - Discrete_Subtype_Definition => - Make_Attribute_Reference (Loc, - Prefix => Make_Identifier (Loc, Chars (A)), - Attribute_Name => Name_Range))), - - Statements => New_List ( - Make_Assignment_Statement (Loc, - Name => B_J, - Expression => Make_Op_Not (Loc, A_J)))); - - Func_Name := Make_Temporary (Loc, 'N'); - Set_Is_Inlined (Func_Name); - - Insert_Action (N, - Make_Subprogram_Body (Loc, - Specification => - Make_Function_Specification (Loc, - Defining_Unit_Name => Func_Name, - Parameter_Specifications => New_List ( - Make_Parameter_Specification (Loc, - Defining_Identifier => A, - Parameter_Type => New_Reference_To (Typ, Loc))), - Result_Definition => New_Reference_To (Typ, Loc)), - - Declarations => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => B, - Object_Definition => New_Reference_To (Arr, Loc))), - - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List ( - Loop_Statement, - Make_Simple_Return_Statement (Loc, - Expression => Make_Identifier (Loc, Chars (B))))))); - - Rewrite (N, - Make_Function_Call (Loc, - Name => New_Reference_To (Func_Name, Loc), - Parameter_Associations => New_List (Opnd))); - - Analyze_And_Resolve (N, Typ); - end Expand_N_Op_Not; - - -------------------- - -- Expand_N_Op_Or -- - -------------------- - - procedure Expand_N_Op_Or (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - if Is_Array_Type (Etype (N)) then - Expand_Boolean_Operator (N); - - elsif Is_Boolean_Type (Etype (N)) then - Adjust_Condition (Left_Opnd (N)); - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - - elsif Is_Intrinsic_Subprogram (Entity (N)) then - Expand_Intrinsic_Call (N, Entity (N)); - - end if; - end Expand_N_Op_Or; - - ---------------------- - -- Expand_N_Op_Plus -- - ---------------------- - - procedure Expand_N_Op_Plus (N : Node_Id) is - begin - Unary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - end Expand_N_Op_Plus; - - --------------------- - -- Expand_N_Op_Rem -- - --------------------- - - procedure Expand_N_Op_Rem (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - - Left : Node_Id; - Right : Node_Id; - - Lo : Uint; - Hi : Uint; - OK : Boolean; - - Lneg : Boolean; - Rneg : Boolean; - -- Set if corresponding operand can be negative - - pragma Unreferenced (Hi); - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - if Is_Integer_Type (Etype (N)) then - Apply_Divide_Checks (N); - - -- All done if we don't have a REM any more, which can happen as a - -- result of overflow expansion in MINIMIZED or ELIMINATED modes. - - if Nkind (N) /= N_Op_Rem then - return; - end if; - end if; - - -- Proceed with expansion of REM - - Left := Left_Opnd (N); - Right := Right_Opnd (N); - - -- Apply optimization x rem 1 = 0. We don't really need that with gcc, - -- but it is useful with other back ends (e.g. AAMP), and is certainly - -- harmless. - - if Is_Integer_Type (Etype (N)) - and then Compile_Time_Known_Value (Right) - and then Expr_Value (Right) = Uint_1 - then - -- Call Remove_Side_Effects to ensure that any side effects in the - -- ignored left operand (in particular function calls to user defined - -- functions) are properly executed. - - Remove_Side_Effects (Left); - - Rewrite (N, Make_Integer_Literal (Loc, 0)); - Analyze_And_Resolve (N, Typ); - return; - end if; - - -- Deal with annoying case of largest negative number remainder minus - -- one. Gigi may not handle this case correctly, because on some - -- targets, the mod value is computed using a divide instruction - -- which gives an overflow trap for this case. - - -- It would be a bit more efficient to figure out which targets this - -- is really needed for, but in practice it is reasonable to do the - -- following special check in all cases, since it means we get a clearer - -- message, and also the overhead is minimal given that division is - -- expensive in any case. - - -- In fact the check is quite easy, if the right operand is -1, then - -- the remainder is always 0, and we can just ignore the left operand - -- completely in this case. - - Determine_Range (Right, OK, Lo, Hi, Assume_Valid => True); - Lneg := (not OK) or else Lo < 0; - - Determine_Range (Left, OK, Lo, Hi, Assume_Valid => True); - Rneg := (not OK) or else Lo < 0; - - -- We won't mess with trying to find out if the left operand can really - -- be the largest negative number (that's a pain in the case of private - -- types and this is really marginal). We will just assume that we need - -- the test if the left operand can be negative at all. - - if Lneg and Rneg then - Rewrite (N, - Make_If_Expression (Loc, - Expressions => New_List ( - Make_Op_Eq (Loc, - Left_Opnd => Duplicate_Subexpr (Right), - Right_Opnd => - Unchecked_Convert_To (Typ, Make_Integer_Literal (Loc, -1))), - - Unchecked_Convert_To (Typ, - Make_Integer_Literal (Loc, Uint_0)), - - Relocate_Node (N)))); - - Set_Analyzed (Next (Next (First (Expressions (N))))); - Analyze_And_Resolve (N, Typ); - end if; - end Expand_N_Op_Rem; - - ----------------------------- - -- Expand_N_Op_Rotate_Left -- - ----------------------------- - - procedure Expand_N_Op_Rotate_Left (N : Node_Id) is - begin - Binary_Op_Validity_Checks (N); - end Expand_N_Op_Rotate_Left; - - ------------------------------ - -- Expand_N_Op_Rotate_Right -- - ------------------------------ - - procedure Expand_N_Op_Rotate_Right (N : Node_Id) is - begin - Binary_Op_Validity_Checks (N); - end Expand_N_Op_Rotate_Right; - - ---------------------------- - -- Expand_N_Op_Shift_Left -- - ---------------------------- - - procedure Expand_N_Op_Shift_Left (N : Node_Id) is - begin - Binary_Op_Validity_Checks (N); - end Expand_N_Op_Shift_Left; - - ----------------------------- - -- Expand_N_Op_Shift_Right -- - ----------------------------- - - procedure Expand_N_Op_Shift_Right (N : Node_Id) is - begin - Binary_Op_Validity_Checks (N); - end Expand_N_Op_Shift_Right; - - ---------------------------------------- - -- Expand_N_Op_Shift_Right_Arithmetic -- - ---------------------------------------- - - procedure Expand_N_Op_Shift_Right_Arithmetic (N : Node_Id) is - begin - Binary_Op_Validity_Checks (N); - end Expand_N_Op_Shift_Right_Arithmetic; - - -------------------------- - -- Expand_N_Op_Subtract -- - -------------------------- - - procedure Expand_N_Op_Subtract (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - -- Check for MINIMIZED/ELIMINATED overflow mode - - if Minimized_Eliminated_Overflow_Check (N) then - Apply_Arithmetic_Overflow_Check (N); - return; - end if; - - -- N - 0 = N for integer types - - if Is_Integer_Type (Typ) - and then Compile_Time_Known_Value (Right_Opnd (N)) - and then Expr_Value (Right_Opnd (N)) = 0 - then - Rewrite (N, Left_Opnd (N)); - return; - end if; - - -- Arithmetic overflow checks for signed integer/fixed point types - - if Is_Signed_Integer_Type (Typ) - or else - Is_Fixed_Point_Type (Typ) - then - Apply_Arithmetic_Overflow_Check (N); - - -- VAX floating-point types case - - elsif Vax_Float (Typ) then - Expand_Vax_Arith (N); - end if; - end Expand_N_Op_Subtract; - - --------------------- - -- Expand_N_Op_Xor -- - --------------------- - - procedure Expand_N_Op_Xor (N : Node_Id) is - Typ : constant Entity_Id := Etype (N); - - begin - Binary_Op_Validity_Checks (N); - - if Is_Array_Type (Etype (N)) then - Expand_Boolean_Operator (N); - - elsif Is_Boolean_Type (Etype (N)) then - Adjust_Condition (Left_Opnd (N)); - Adjust_Condition (Right_Opnd (N)); - Set_Etype (N, Standard_Boolean); - Adjust_Result_Type (N, Typ); - - elsif Is_Intrinsic_Subprogram (Entity (N)) then - Expand_Intrinsic_Call (N, Entity (N)); - - end if; - end Expand_N_Op_Xor; - - ---------------------- - -- Expand_N_Or_Else -- - ---------------------- - - procedure Expand_N_Or_Else (N : Node_Id) - renames Expand_Short_Circuit_Operator; - - ----------------------------------- - -- Expand_N_Qualified_Expression -- - ----------------------------------- - - procedure Expand_N_Qualified_Expression (N : Node_Id) is - Operand : constant Node_Id := Expression (N); - Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); - - begin - -- Do validity check if validity checking operands - - if Validity_Checks_On and then Validity_Check_Operands then - Ensure_Valid (Operand); - end if; - - -- Apply possible constraint check - - Apply_Constraint_Check (Operand, Target_Type, No_Sliding => True); - - if Do_Range_Check (Operand) then - Set_Do_Range_Check (Operand, False); - Generate_Range_Check (Operand, Target_Type, CE_Range_Check_Failed); - end if; - end Expand_N_Qualified_Expression; - - ------------------------------------ - -- Expand_N_Quantified_Expression -- - ------------------------------------ - - -- We expand: - - -- for all X in range => Cond - - -- into: - - -- T := True; - -- for X in range loop - -- if not Cond then - -- T := False; - -- exit; - -- end if; - -- end loop; - - -- Similarly, an existentially quantified expression: - - -- for some X in range => Cond - - -- becomes: - - -- T := False; - -- for X in range loop - -- if Cond then - -- T := True; - -- exit; - -- end if; - -- end loop; - - -- In both cases, the iteration may be over a container in which case it is - -- given by an iterator specification, not a loop parameter specification. - - procedure Expand_N_Quantified_Expression (N : Node_Id) is - Actions : constant List_Id := New_List; - For_All : constant Boolean := All_Present (N); - Iter_Spec : constant Node_Id := Iterator_Specification (N); - Loc : constant Source_Ptr := Sloc (N); - Loop_Spec : constant Node_Id := Loop_Parameter_Specification (N); - Cond : Node_Id; - Flag : Entity_Id; - Scheme : Node_Id; - Stmts : List_Id; - - begin - -- Create the declaration of the flag which tracks the status of the - -- quantified expression. Generate: - - -- Flag : Boolean := (True | False); - - Flag := Make_Temporary (Loc, 'T', N); - - Append_To (Actions, - Make_Object_Declaration (Loc, - Defining_Identifier => Flag, - Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), - Expression => - New_Occurrence_Of (Boolean_Literals (For_All), Loc))); - - -- Construct the circuitry which tracks the status of the quantified - -- expression. Generate: - - -- if [not] Cond then - -- Flag := (False | True); - -- exit; - -- end if; - - Cond := Relocate_Node (Condition (N)); - - if For_All then - Cond := Make_Op_Not (Loc, Cond); - end if; - - Stmts := New_List ( - Make_Implicit_If_Statement (N, - Condition => Cond, - Then_Statements => New_List ( - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Flag, Loc), - Expression => - New_Occurrence_Of (Boolean_Literals (not For_All), Loc)), - Make_Exit_Statement (Loc)))); - - -- Build the loop equivalent of the quantified expression - - if Present (Iter_Spec) then - Scheme := - Make_Iteration_Scheme (Loc, - Iterator_Specification => Iter_Spec); - else - Scheme := - Make_Iteration_Scheme (Loc, - Loop_Parameter_Specification => Loop_Spec); - end if; - - Append_To (Actions, - Make_Loop_Statement (Loc, - Iteration_Scheme => Scheme, - Statements => Stmts, - End_Label => Empty)); - - -- Transform the quantified expression - - Rewrite (N, - Make_Expression_With_Actions (Loc, - Expression => New_Occurrence_Of (Flag, Loc), - Actions => Actions)); - Analyze_And_Resolve (N, Standard_Boolean); - end Expand_N_Quantified_Expression; - - --------------------------------- - -- Expand_N_Selected_Component -- - --------------------------------- - - procedure Expand_N_Selected_Component (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Par : constant Node_Id := Parent (N); - P : constant Node_Id := Prefix (N); - Ptyp : Entity_Id := Underlying_Type (Etype (P)); - Disc : Entity_Id; - New_N : Node_Id; - Dcon : Elmt_Id; - Dval : Node_Id; - - function In_Left_Hand_Side (Comp : Node_Id) return Boolean; - -- Gigi needs a temporary for prefixes that depend on a discriminant, - -- unless the context of an assignment can provide size information. - -- Don't we have a general routine that does this??? - - function Is_Subtype_Declaration return Boolean; - -- The replacement of a discriminant reference by its value is required - -- if this is part of the initialization of an temporary generated by a - -- change of representation. This shows up as the construction of a - -- discriminant constraint for a subtype declared at the same point as - -- the entity in the prefix of the selected component. We recognize this - -- case when the context of the reference is: - -- subtype ST is T(Obj.D); - -- where the entity for Obj comes from source, and ST has the same sloc. - - ----------------------- - -- In_Left_Hand_Side -- - ----------------------- - - function In_Left_Hand_Side (Comp : Node_Id) return Boolean is - begin - return (Nkind (Parent (Comp)) = N_Assignment_Statement - and then Comp = Name (Parent (Comp))) - or else (Present (Parent (Comp)) - and then Nkind (Parent (Comp)) in N_Subexpr - and then In_Left_Hand_Side (Parent (Comp))); - end In_Left_Hand_Side; - - ----------------------------- - -- Is_Subtype_Declaration -- - ----------------------------- - - function Is_Subtype_Declaration return Boolean is - Par : constant Node_Id := Parent (N); - begin - return - Nkind (Par) = N_Index_Or_Discriminant_Constraint - and then Nkind (Parent (Parent (Par))) = N_Subtype_Declaration - and then Comes_From_Source (Entity (Prefix (N))) - and then Sloc (Par) = Sloc (Entity (Prefix (N))); - end Is_Subtype_Declaration; - - -- Start of processing for Expand_N_Selected_Component - - begin - -- Insert explicit dereference if required - - if Is_Access_Type (Ptyp) then - - -- First set prefix type to proper access type, in case it currently - -- has a private (non-access) view of this type. - - Set_Etype (P, Ptyp); - - Insert_Explicit_Dereference (P); - Analyze_And_Resolve (P, Designated_Type (Ptyp)); - - if Ekind (Etype (P)) = E_Private_Subtype - and then Is_For_Access_Subtype (Etype (P)) - then - Set_Etype (P, Base_Type (Etype (P))); - end if; - - Ptyp := Etype (P); - end if; - - -- Deal with discriminant check required - - if Do_Discriminant_Check (N) then - - -- Present the discriminant checking function to the backend, so that - -- it can inline the call to the function. - - Add_Inlined_Body - (Discriminant_Checking_Func - (Original_Record_Component (Entity (Selector_Name (N))))); - - -- Now reset the flag and generate the call - - Set_Do_Discriminant_Check (N, False); - Generate_Discriminant_Check (N); - end if; - - -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place - -- function, then additional actuals must be passed. - - if Ada_Version >= Ada_2005 - and then Is_Build_In_Place_Function_Call (P) - then - Make_Build_In_Place_Call_In_Anonymous_Context (P); - end if; - - -- Gigi cannot handle unchecked conversions that are the prefix of a - -- selected component with discriminants. This must be checked during - -- expansion, because during analysis the type of the selector is not - -- known at the point the prefix is analyzed. If the conversion is the - -- target of an assignment, then we cannot force the evaluation. - - if Nkind (Prefix (N)) = N_Unchecked_Type_Conversion - and then Has_Discriminants (Etype (N)) - and then not In_Left_Hand_Side (N) - then - Force_Evaluation (Prefix (N)); - end if; - - -- Remaining processing applies only if selector is a discriminant - - if Ekind (Entity (Selector_Name (N))) = E_Discriminant then - - -- If the selector is a discriminant of a constrained record type, - -- we may be able to rewrite the expression with the actual value - -- of the discriminant, a useful optimization in some cases. - - if Is_Record_Type (Ptyp) - and then Has_Discriminants (Ptyp) - and then Is_Constrained (Ptyp) - then - -- Do this optimization for discrete types only, and not for - -- access types (access discriminants get us into trouble!) - - if not Is_Discrete_Type (Etype (N)) then - null; - - -- Don't do this on the left hand of an assignment statement. - -- Normally one would think that references like this would not - -- occur, but they do in generated code, and mean that we really - -- do want to assign the discriminant! - - elsif Nkind (Par) = N_Assignment_Statement - and then Name (Par) = N - then - null; - - -- Don't do this optimization for the prefix of an attribute or - -- the name of an object renaming declaration since these are - -- contexts where we do not want the value anyway. - - elsif (Nkind (Par) = N_Attribute_Reference - and then Prefix (Par) = N) - or else Is_Renamed_Object (N) - then - null; - - -- Don't do this optimization if we are within the code for a - -- discriminant check, since the whole point of such a check may - -- be to verify the condition on which the code below depends! - - elsif Is_In_Discriminant_Check (N) then - null; - - -- Green light to see if we can do the optimization. There is - -- still one condition that inhibits the optimization below but - -- now is the time to check the particular discriminant. - - else - -- Loop through discriminants to find the matching discriminant - -- constraint to see if we can copy it. - - Disc := First_Discriminant (Ptyp); - Dcon := First_Elmt (Discriminant_Constraint (Ptyp)); - Discr_Loop : while Present (Dcon) loop - Dval := Node (Dcon); - - -- Check if this is the matching discriminant and if the - -- discriminant value is simple enough to make sense to - -- copy. We don't want to copy complex expressions, and - -- indeed to do so can cause trouble (before we put in - -- this guard, a discriminant expression containing an - -- AND THEN was copied, causing problems for coverage - -- analysis tools). - - -- However, if the reference is part of the initialization - -- code generated for an object declaration, we must use - -- the discriminant value from the subtype constraint, - -- because the selected component may be a reference to the - -- object being initialized, whose discriminant is not yet - -- set. This only happens in complex cases involving changes - -- or representation. - - if Disc = Entity (Selector_Name (N)) - and then (Is_Entity_Name (Dval) - or else Compile_Time_Known_Value (Dval) - or else Is_Subtype_Declaration) - then - -- Here we have the matching discriminant. Check for - -- the case of a discriminant of a component that is - -- constrained by an outer discriminant, which cannot - -- be optimized away. - - if Denotes_Discriminant - (Dval, Check_Concurrent => True) - then - exit Discr_Loop; - - elsif Nkind (Original_Node (Dval)) = N_Selected_Component - and then - Denotes_Discriminant - (Selector_Name (Original_Node (Dval)), True) - then - exit Discr_Loop; - - -- Do not retrieve value if constraint is not static. It - -- is generally not useful, and the constraint may be a - -- rewritten outer discriminant in which case it is in - -- fact incorrect. - - elsif Is_Entity_Name (Dval) - and then Nkind (Parent (Entity (Dval))) = - N_Object_Declaration - and then Present (Expression (Parent (Entity (Dval)))) - and then - not Is_Static_Expression - (Expression (Parent (Entity (Dval)))) - then - exit Discr_Loop; - - -- In the context of a case statement, the expression may - -- have the base type of the discriminant, and we need to - -- preserve the constraint to avoid spurious errors on - -- missing cases. - - elsif Nkind (Parent (N)) = N_Case_Statement - and then Etype (Dval) /= Etype (Disc) - then - Rewrite (N, - Make_Qualified_Expression (Loc, - Subtype_Mark => - New_Occurrence_Of (Etype (Disc), Loc), - Expression => - New_Copy_Tree (Dval))); - Analyze_And_Resolve (N, Etype (Disc)); - - -- In case that comes out as a static expression, - -- reset it (a selected component is never static). - - Set_Is_Static_Expression (N, False); - return; - - -- Otherwise we can just copy the constraint, but the - -- result is certainly not static! In some cases the - -- discriminant constraint has been analyzed in the - -- context of the original subtype indication, but for - -- itypes the constraint might not have been analyzed - -- yet, and this must be done now. - - else - Rewrite (N, New_Copy_Tree (Dval)); - Analyze_And_Resolve (N); - Set_Is_Static_Expression (N, False); - return; - end if; - end if; - - Next_Elmt (Dcon); - Next_Discriminant (Disc); - end loop Discr_Loop; - - -- Note: the above loop should always find a matching - -- discriminant, but if it does not, we just missed an - -- optimization due to some glitch (perhaps a previous - -- error), so ignore. - - end if; - end if; - - -- The only remaining processing is in the case of a discriminant of - -- a concurrent object, where we rewrite the prefix to denote the - -- corresponding record type. If the type is derived and has renamed - -- discriminants, use corresponding discriminant, which is the one - -- that appears in the corresponding record. - - if not Is_Concurrent_Type (Ptyp) then - return; - end if; - - Disc := Entity (Selector_Name (N)); - - if Is_Derived_Type (Ptyp) - and then Present (Corresponding_Discriminant (Disc)) - then - Disc := Corresponding_Discriminant (Disc); - end if; - - New_N := - Make_Selected_Component (Loc, - Prefix => - Unchecked_Convert_To (Corresponding_Record_Type (Ptyp), - New_Copy_Tree (P)), - Selector_Name => Make_Identifier (Loc, Chars (Disc))); - - Rewrite (N, New_N); - Analyze (N); - end if; - - -- Set Atomic_Sync_Required if necessary for atomic component - - if Nkind (N) = N_Selected_Component then - declare - E : constant Entity_Id := Entity (Selector_Name (N)); - Set : Boolean; - - begin - -- If component is atomic, but type is not, setting depends on - -- disable/enable state for the component. - - if Is_Atomic (E) and then not Is_Atomic (Etype (E)) then - Set := not Atomic_Synchronization_Disabled (E); - - -- If component is not atomic, but its type is atomic, setting - -- depends on disable/enable state for the type. - - elsif not Is_Atomic (E) and then Is_Atomic (Etype (E)) then - Set := not Atomic_Synchronization_Disabled (Etype (E)); - - -- If both component and type are atomic, we disable if either - -- component or its type have sync disabled. - - elsif Is_Atomic (E) and then Is_Atomic (Etype (E)) then - Set := (not Atomic_Synchronization_Disabled (E)) - and then - (not Atomic_Synchronization_Disabled (Etype (E))); - - else - Set := False; - end if; - - -- Set flag if required - - if Set then - Activate_Atomic_Synchronization (N); - end if; - end; - end if; - end Expand_N_Selected_Component; - - -------------------- - -- Expand_N_Slice -- - -------------------- - - procedure Expand_N_Slice (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Pfx : constant Node_Id := Prefix (N); - Ptp : Entity_Id := Etype (Pfx); - - function Is_Procedure_Actual (N : Node_Id) return Boolean; - -- Check whether the argument is an actual for a procedure call, in - -- which case the expansion of a bit-packed slice is deferred until the - -- call itself is expanded. The reason this is required is that we might - -- have an IN OUT or OUT parameter, and the copy out is essential, and - -- that copy out would be missed if we created a temporary here in - -- Expand_N_Slice. Note that we don't bother to test specifically for an - -- IN OUT or OUT mode parameter, since it is a bit tricky to do, and it - -- is harmless to defer expansion in the IN case, since the call - -- processing will still generate the appropriate copy in operation, - -- which will take care of the slice. - - procedure Make_Temporary_For_Slice; - -- Create a named variable for the value of the slice, in cases where - -- the back-end cannot handle it properly, e.g. when packed types or - -- unaligned slices are involved. - - ------------------------- - -- Is_Procedure_Actual -- - ------------------------- - - function Is_Procedure_Actual (N : Node_Id) return Boolean is - Par : Node_Id := Parent (N); - - begin - loop - -- If our parent is a procedure call we can return - - if Nkind (Par) = N_Procedure_Call_Statement then - return True; - - -- If our parent is a type conversion, keep climbing the tree, - -- since a type conversion can be a procedure actual. Also keep - -- climbing if parameter association or a qualified expression, - -- since these are additional cases that do can appear on - -- procedure actuals. - - elsif Nkind_In (Par, N_Type_Conversion, - N_Parameter_Association, - N_Qualified_Expression) - then - Par := Parent (Par); - - -- Any other case is not what we are looking for - - else - return False; - end if; - end loop; - end Is_Procedure_Actual; - - ------------------------------ - -- Make_Temporary_For_Slice -- - ------------------------------ - - procedure Make_Temporary_For_Slice is - Decl : Node_Id; - Ent : constant Entity_Id := Make_Temporary (Loc, 'T', N); - - begin - Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Ent, - Object_Definition => New_Occurrence_Of (Typ, Loc)); - - Set_No_Initialization (Decl); - - Insert_Actions (N, New_List ( - Decl, - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Ent, Loc), - Expression => Relocate_Node (N)))); - - Rewrite (N, New_Occurrence_Of (Ent, Loc)); - Analyze_And_Resolve (N, Typ); - end Make_Temporary_For_Slice; - - -- Start of processing for Expand_N_Slice - - begin - -- Special handling for access types - - if Is_Access_Type (Ptp) then - - Ptp := Designated_Type (Ptp); - - Rewrite (Pfx, - Make_Explicit_Dereference (Sloc (N), - Prefix => Relocate_Node (Pfx))); - - Analyze_And_Resolve (Pfx, Ptp); - end if; - - -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place - -- function, then additional actuals must be passed. - - if Ada_Version >= Ada_2005 - and then Is_Build_In_Place_Function_Call (Pfx) - then - Make_Build_In_Place_Call_In_Anonymous_Context (Pfx); - end if; - - -- The remaining case to be handled is packed slices. We can leave - -- packed slices as they are in the following situations: - - -- 1. Right or left side of an assignment (we can handle this - -- situation correctly in the assignment statement expansion). - - -- 2. Prefix of indexed component (the slide is optimized away in this - -- case, see the start of Expand_N_Slice.) - - -- 3. Object renaming declaration, since we want the name of the - -- slice, not the value. - - -- 4. Argument to procedure call, since copy-in/copy-out handling may - -- be required, and this is handled in the expansion of call - -- itself. - - -- 5. Prefix of an address attribute (this is an error which is caught - -- elsewhere, and the expansion would interfere with generating the - -- error message). - - if not Is_Packed (Typ) then - - -- Apply transformation for actuals of a function call, where - -- Expand_Actuals is not used. - - if Nkind (Parent (N)) = N_Function_Call - and then Is_Possibly_Unaligned_Slice (N) - then - Make_Temporary_For_Slice; - end if; - - elsif Nkind (Parent (N)) = N_Assignment_Statement - or else (Nkind (Parent (Parent (N))) = N_Assignment_Statement - and then Parent (N) = Name (Parent (Parent (N)))) - then - return; - - elsif Nkind (Parent (N)) = N_Indexed_Component - or else Is_Renamed_Object (N) - or else Is_Procedure_Actual (N) - then - return; - - elsif Nkind (Parent (N)) = N_Attribute_Reference - and then Attribute_Name (Parent (N)) = Name_Address - then - return; - - else - Make_Temporary_For_Slice; - end if; - end Expand_N_Slice; - - ------------------------------ - -- Expand_N_Type_Conversion -- - ------------------------------ - - procedure Expand_N_Type_Conversion (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Operand : constant Node_Id := Expression (N); - Target_Type : constant Entity_Id := Etype (N); - Operand_Type : Entity_Id := Etype (Operand); - - procedure Handle_Changed_Representation; - -- This is called in the case of record and array type conversions to - -- see if there is a change of representation to be handled. Change of - -- representation is actually handled at the assignment statement level, - -- and what this procedure does is rewrite node N conversion as an - -- assignment to temporary. If there is no change of representation, - -- then the conversion node is unchanged. - - procedure Raise_Accessibility_Error; - -- Called when we know that an accessibility check will fail. Rewrites - -- node N to an appropriate raise statement and outputs warning msgs. - -- The Etype of the raise node is set to Target_Type. - - procedure Real_Range_Check; - -- Handles generation of range check for real target value - - function Has_Extra_Accessibility (Id : Entity_Id) return Boolean; - -- True iff Present (Effective_Extra_Accessibility (Id)) successfully - -- evaluates to True. - - ----------------------------------- - -- Handle_Changed_Representation -- - ----------------------------------- - - procedure Handle_Changed_Representation is - Temp : Entity_Id; - Decl : Node_Id; - Odef : Node_Id; - Disc : Node_Id; - N_Ix : Node_Id; - Cons : List_Id; - - begin - -- Nothing else to do if no change of representation - - if Same_Representation (Operand_Type, Target_Type) then - return; - - -- The real change of representation work is done by the assignment - -- statement processing. So if this type conversion is appearing as - -- the expression of an assignment statement, nothing needs to be - -- done to the conversion. - - elsif Nkind (Parent (N)) = N_Assignment_Statement then - return; - - -- Otherwise we need to generate a temporary variable, and do the - -- change of representation assignment into that temporary variable. - -- The conversion is then replaced by a reference to this variable. - - else - Cons := No_List; - - -- If type is unconstrained we have to add a constraint, copied - -- from the actual value of the left hand side. - - if not Is_Constrained (Target_Type) then - if Has_Discriminants (Operand_Type) then - Disc := First_Discriminant (Operand_Type); - - if Disc /= First_Stored_Discriminant (Operand_Type) then - Disc := First_Stored_Discriminant (Operand_Type); - end if; - - Cons := New_List; - while Present (Disc) loop - Append_To (Cons, - Make_Selected_Component (Loc, - Prefix => - Duplicate_Subexpr_Move_Checks (Operand), - Selector_Name => - Make_Identifier (Loc, Chars (Disc)))); - Next_Discriminant (Disc); - end loop; - - elsif Is_Array_Type (Operand_Type) then - N_Ix := First_Index (Target_Type); - Cons := New_List; - - for J in 1 .. Number_Dimensions (Operand_Type) loop - - -- We convert the bounds explicitly. We use an unchecked - -- conversion because bounds checks are done elsewhere. - - Append_To (Cons, - Make_Range (Loc, - Low_Bound => - Unchecked_Convert_To (Etype (N_Ix), - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr_No_Checks - (Operand, Name_Req => True), - Attribute_Name => Name_First, - Expressions => New_List ( - Make_Integer_Literal (Loc, J)))), - - High_Bound => - Unchecked_Convert_To (Etype (N_Ix), - Make_Attribute_Reference (Loc, - Prefix => - Duplicate_Subexpr_No_Checks - (Operand, Name_Req => True), - Attribute_Name => Name_Last, - Expressions => New_List ( - Make_Integer_Literal (Loc, J)))))); - - Next_Index (N_Ix); - end loop; - end if; - end if; - - Odef := New_Occurrence_Of (Target_Type, Loc); - - if Present (Cons) then - Odef := - Make_Subtype_Indication (Loc, - Subtype_Mark => Odef, - Constraint => - Make_Index_Or_Discriminant_Constraint (Loc, - Constraints => Cons)); - end if; - - Temp := Make_Temporary (Loc, 'C'); - Decl := - Make_Object_Declaration (Loc, - Defining_Identifier => Temp, - Object_Definition => Odef); - - Set_No_Initialization (Decl, True); - - -- Insert required actions. It is essential to suppress checks - -- since we have suppressed default initialization, which means - -- that the variable we create may have no discriminants. - - Insert_Actions (N, - New_List ( - Decl, - Make_Assignment_Statement (Loc, - Name => New_Occurrence_Of (Temp, Loc), - Expression => Relocate_Node (N))), - Suppress => All_Checks); - - Rewrite (N, New_Occurrence_Of (Temp, Loc)); - return; - end if; - end Handle_Changed_Representation; - - ------------------------------- - -- Raise_Accessibility_Error -- - ------------------------------- - - procedure Raise_Accessibility_Error is - begin - Rewrite (N, - Make_Raise_Program_Error (Sloc (N), - Reason => PE_Accessibility_Check_Failed)); - Set_Etype (N, Target_Type); - - Error_Msg_N - ("??accessibility check failure", N); - Error_Msg_NE - ("\??& will be raised at run time", N, Standard_Program_Error); - end Raise_Accessibility_Error; - - ---------------------- - -- Real_Range_Check -- - ---------------------- - - -- Case of conversions to floating-point or fixed-point. If range checks - -- are enabled and the target type has a range constraint, we convert: - - -- typ (x) - - -- to - - -- Tnn : typ'Base := typ'Base (x); - -- [constraint_error when Tnn < typ'First or else Tnn > typ'Last] - -- Tnn - - -- This is necessary when there is a conversion of integer to float or - -- to fixed-point to ensure that the correct checks are made. It is not - -- necessary for float to float where it is enough to simply set the - -- Do_Range_Check flag. - - procedure Real_Range_Check is - Btyp : constant Entity_Id := Base_Type (Target_Type); - Lo : constant Node_Id := Type_Low_Bound (Target_Type); - Hi : constant Node_Id := Type_High_Bound (Target_Type); - Xtyp : constant Entity_Id := Etype (Operand); - Conv : Node_Id; - Tnn : Entity_Id; - - begin - -- Nothing to do if conversion was rewritten - - if Nkind (N) /= N_Type_Conversion then - return; - end if; - - -- Nothing to do if range checks suppressed, or target has the same - -- range as the base type (or is the base type). - - if Range_Checks_Suppressed (Target_Type) - or else (Lo = Type_Low_Bound (Btyp) - and then - Hi = Type_High_Bound (Btyp)) - then - return; - end if; - - -- Nothing to do if expression is an entity on which checks have been - -- suppressed. - - if Is_Entity_Name (Operand) - and then Range_Checks_Suppressed (Entity (Operand)) - then - return; - end if; - - -- Nothing to do if bounds are all static and we can tell that the - -- expression is within the bounds of the target. Note that if the - -- operand is of an unconstrained floating-point type, then we do - -- not trust it to be in range (might be infinite) - - declare - S_Lo : constant Node_Id := Type_Low_Bound (Xtyp); - S_Hi : constant Node_Id := Type_High_Bound (Xtyp); - - begin - if (not Is_Floating_Point_Type (Xtyp) - or else Is_Constrained (Xtyp)) - and then Compile_Time_Known_Value (S_Lo) - and then Compile_Time_Known_Value (S_Hi) - and then Compile_Time_Known_Value (Hi) - and then Compile_Time_Known_Value (Lo) - then - declare - D_Lov : constant Ureal := Expr_Value_R (Lo); - D_Hiv : constant Ureal := Expr_Value_R (Hi); - S_Lov : Ureal; - S_Hiv : Ureal; - - begin - if Is_Real_Type (Xtyp) then - S_Lov := Expr_Value_R (S_Lo); - S_Hiv := Expr_Value_R (S_Hi); - else - S_Lov := UR_From_Uint (Expr_Value (S_Lo)); - S_Hiv := UR_From_Uint (Expr_Value (S_Hi)); - end if; - - if D_Hiv > D_Lov - and then S_Lov >= D_Lov - and then S_Hiv <= D_Hiv - then - Set_Do_Range_Check (Operand, False); - return; - end if; - end; - end if; - end; - - -- For float to float conversions, we are done - - if Is_Floating_Point_Type (Xtyp) - and then - Is_Floating_Point_Type (Btyp) - then - return; - end if; - - -- Otherwise rewrite the conversion as described above - - Conv := Relocate_Node (N); - Rewrite (Subtype_Mark (Conv), New_Occurrence_Of (Btyp, Loc)); - Set_Etype (Conv, Btyp); - - -- Enable overflow except for case of integer to float conversions, - -- where it is never required, since we can never have overflow in - -- this case. - - if not Is_Integer_Type (Etype (Operand)) then - Enable_Overflow_Check (Conv); - end if; - - Tnn := Make_Temporary (Loc, 'T', Conv); - - Insert_Actions (N, New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => Tnn, - Object_Definition => New_Occurrence_Of (Btyp, Loc), - Constant_Present => True, - Expression => Conv), - - Make_Raise_Constraint_Error (Loc, - Condition => - Make_Or_Else (Loc, - Left_Opnd => - Make_Op_Lt (Loc, - Left_Opnd => New_Occurrence_Of (Tnn, Loc), - Right_Opnd => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_First, - Prefix => - New_Occurrence_Of (Target_Type, Loc))), - - Right_Opnd => - Make_Op_Gt (Loc, - Left_Opnd => New_Occurrence_Of (Tnn, Loc), - Right_Opnd => - Make_Attribute_Reference (Loc, - Attribute_Name => Name_Last, - Prefix => - New_Occurrence_Of (Target_Type, Loc)))), - Reason => CE_Range_Check_Failed))); - - Rewrite (N, New_Occurrence_Of (Tnn, Loc)); - Analyze_And_Resolve (N, Btyp); - end Real_Range_Check; - - ----------------------------- - -- Has_Extra_Accessibility -- - ----------------------------- - - -- Returns true for a formal of an anonymous access type or for - -- an Ada 2012-style stand-alone object of an anonymous access type. - - function Has_Extra_Accessibility (Id : Entity_Id) return Boolean is - begin - if Is_Formal (Id) or else Ekind_In (Id, E_Constant, E_Variable) then - return Present (Effective_Extra_Accessibility (Id)); - else - return False; - end if; - end Has_Extra_Accessibility; - - -- Start of processing for Expand_N_Type_Conversion - - begin - -- Nothing at all to do if conversion is to the identical type so remove - -- the conversion completely, it is useless, except that it may carry - -- an Assignment_OK attribute, which must be propagated to the operand. - - if Operand_Type = Target_Type then - if Assignment_OK (N) then - Set_Assignment_OK (Operand); - end if; - - Rewrite (N, Relocate_Node (Operand)); - goto Done; - end if; - - -- Nothing to do if this is the second argument of read. This is a - -- "backwards" conversion that will be handled by the specialized code - -- in attribute processing. - - if Nkind (Parent (N)) = N_Attribute_Reference - and then Attribute_Name (Parent (N)) = Name_Read - and then Next (First (Expressions (Parent (N)))) = N - then - goto Done; - end if; - - -- Check for case of converting to a type that has an invariant - -- associated with it. This required an invariant check. We convert - - -- typ (expr) - - -- into - - -- do invariant_check (typ (expr)) in typ (expr); - - -- using Duplicate_Subexpr to avoid multiple side effects - - -- Note: the Comes_From_Source check, and then the resetting of this - -- flag prevents what would otherwise be an infinite recursion. - - if Has_Invariants (Target_Type) - and then Present (Invariant_Procedure (Target_Type)) - and then Comes_From_Source (N) - then - Set_Comes_From_Source (N, False); - Rewrite (N, - Make_Expression_With_Actions (Loc, - Actions => New_List ( - Make_Invariant_Call (Duplicate_Subexpr (N))), - Expression => Duplicate_Subexpr_No_Checks (N))); - Analyze_And_Resolve (N, Target_Type); - goto Done; - end if; - - -- Here if we may need to expand conversion - - -- If the operand of the type conversion is an arithmetic operation on - -- signed integers, and the based type of the signed integer type in - -- question is smaller than Standard.Integer, we promote both of the - -- operands to type Integer. - - -- For example, if we have - - -- target-type (opnd1 + opnd2) - - -- and opnd1 and opnd2 are of type short integer, then we rewrite - -- this as: - - -- target-type (integer(opnd1) + integer(opnd2)) - - -- We do this because we are always allowed to compute in a larger type - -- if we do the right thing with the result, and in this case we are - -- going to do a conversion which will do an appropriate check to make - -- sure that things are in range of the target type in any case. This - -- avoids some unnecessary intermediate overflows. - - -- We might consider a similar transformation in the case where the - -- target is a real type or a 64-bit integer type, and the operand - -- is an arithmetic operation using a 32-bit integer type. However, - -- we do not bother with this case, because it could cause significant - -- inefficiencies on 32-bit machines. On a 64-bit machine it would be - -- much cheaper, but we don't want different behavior on 32-bit and - -- 64-bit machines. Note that the exclusion of the 64-bit case also - -- handles the configurable run-time cases where 64-bit arithmetic - -- may simply be unavailable. - - -- Note: this circuit is partially redundant with respect to the circuit - -- in Checks.Apply_Arithmetic_Overflow_Check, but we catch more cases in - -- the processing here. Also we still need the Checks circuit, since we - -- have to be sure not to generate junk overflow checks in the first - -- place, since it would be trick to remove them here! - - if Integer_Promotion_Possible (N) then - - -- All conditions met, go ahead with transformation - - declare - Opnd : Node_Id; - L, R : Node_Id; - - begin - R := - Make_Type_Conversion (Loc, - Subtype_Mark => New_Reference_To (Standard_Integer, Loc), - Expression => Relocate_Node (Right_Opnd (Operand))); - - Opnd := New_Op_Node (Nkind (Operand), Loc); - Set_Right_Opnd (Opnd, R); - - if Nkind (Operand) in N_Binary_Op then - L := - Make_Type_Conversion (Loc, - Subtype_Mark => New_Reference_To (Standard_Integer, Loc), - Expression => Relocate_Node (Left_Opnd (Operand))); - - Set_Left_Opnd (Opnd, L); - end if; - - Rewrite (N, - Make_Type_Conversion (Loc, - Subtype_Mark => Relocate_Node (Subtype_Mark (N)), - Expression => Opnd)); - - Analyze_And_Resolve (N, Target_Type); - goto Done; - end; - end if; - - -- Do validity check if validity checking operands - - if Validity_Checks_On - and then Validity_Check_Operands - then - Ensure_Valid (Operand); - end if; - - -- Special case of converting from non-standard boolean type - - if Is_Boolean_Type (Operand_Type) - and then (Nonzero_Is_True (Operand_Type)) - then - Adjust_Condition (Operand); - Set_Etype (Operand, Standard_Boolean); - Operand_Type := Standard_Boolean; - end if; - - -- Case of converting to an access type - - if Is_Access_Type (Target_Type) then - - -- Apply an accessibility check when the conversion operand is an - -- access parameter (or a renaming thereof), unless conversion was - -- expanded from an Unchecked_ or Unrestricted_Access attribute. - -- Note that other checks may still need to be applied below (such - -- as tagged type checks). - - if Is_Entity_Name (Operand) - and then Has_Extra_Accessibility (Entity (Operand)) - and then Ekind (Etype (Operand)) = E_Anonymous_Access_Type - and then (Nkind (Original_Node (N)) /= N_Attribute_Reference - or else Attribute_Name (Original_Node (N)) = Name_Access) - then - Apply_Accessibility_Check - (Operand, Target_Type, Insert_Node => Operand); - - -- If the level of the operand type is statically deeper than the - -- level of the target type, then force Program_Error. Note that this - -- can only occur for cases where the attribute is within the body of - -- an instantiation (otherwise the conversion will already have been - -- rejected as illegal). Note: warnings are issued by the analyzer - -- for the instance cases. - - elsif In_Instance_Body - and then Type_Access_Level (Operand_Type) > - Type_Access_Level (Target_Type) - then - Raise_Accessibility_Error; - - -- When the operand is a selected access discriminant the check needs - -- to be made against the level of the object denoted by the prefix - -- of the selected name. Force Program_Error for this case as well - -- (this accessibility violation can only happen if within the body - -- of an instantiation). - - elsif In_Instance_Body - and then Ekind (Operand_Type) = E_Anonymous_Access_Type - and then Nkind (Operand) = N_Selected_Component - and then Object_Access_Level (Operand) > - Type_Access_Level (Target_Type) - then - Raise_Accessibility_Error; - goto Done; - end if; - end if; - - -- Case of conversions of tagged types and access to tagged types - - -- When needed, that is to say when the expression is class-wide, Add - -- runtime a tag check for (strict) downward conversion by using the - -- membership test, generating: - - -- [constraint_error when Operand not in Target_Type'Class] - - -- or in the access type case - - -- [constraint_error - -- when Operand /= null - -- and then Operand.all not in - -- Designated_Type (Target_Type)'Class] - - if (Is_Access_Type (Target_Type) - and then Is_Tagged_Type (Designated_Type (Target_Type))) - or else Is_Tagged_Type (Target_Type) - then - -- Do not do any expansion in the access type case if the parent is a - -- renaming, since this is an error situation which will be caught by - -- Sem_Ch8, and the expansion can interfere with this error check. - - if Is_Access_Type (Target_Type) and then Is_Renamed_Object (N) then - goto Done; - end if; - - -- Otherwise, proceed with processing tagged conversion - - Tagged_Conversion : declare - Actual_Op_Typ : Entity_Id; - Actual_Targ_Typ : Entity_Id; - Make_Conversion : Boolean := False; - Root_Op_Typ : Entity_Id; - - procedure Make_Tag_Check (Targ_Typ : Entity_Id); - -- Create a membership check to test whether Operand is a member - -- of Targ_Typ. If the original Target_Type is an access, include - -- a test for null value. The check is inserted at N. - - -------------------- - -- Make_Tag_Check -- - -------------------- - - procedure Make_Tag_Check (Targ_Typ : Entity_Id) is - Cond : Node_Id; - - begin - -- Generate: - -- [Constraint_Error - -- when Operand /= null - -- and then Operand.all not in Targ_Typ] - - if Is_Access_Type (Target_Type) then - Cond := - Make_And_Then (Loc, - Left_Opnd => - Make_Op_Ne (Loc, - Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), - Right_Opnd => Make_Null (Loc)), - - Right_Opnd => - Make_Not_In (Loc, - Left_Opnd => - Make_Explicit_Dereference (Loc, - Prefix => Duplicate_Subexpr_No_Checks (Operand)), - Right_Opnd => New_Reference_To (Targ_Typ, Loc))); - - -- Generate: - -- [Constraint_Error when Operand not in Targ_Typ] - - else - Cond := - Make_Not_In (Loc, - Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), - Right_Opnd => New_Reference_To (Targ_Typ, Loc)); - end if; - - Insert_Action (N, - Make_Raise_Constraint_Error (Loc, - Condition => Cond, - Reason => CE_Tag_Check_Failed)); - end Make_Tag_Check; - - -- Start of processing for Tagged_Conversion - - begin - -- Handle entities from the limited view - - if Is_Access_Type (Operand_Type) then - Actual_Op_Typ := - Available_View (Designated_Type (Operand_Type)); - else - Actual_Op_Typ := Operand_Type; - end if; - - if Is_Access_Type (Target_Type) then - Actual_Targ_Typ := - Available_View (Designated_Type (Target_Type)); - else - Actual_Targ_Typ := Target_Type; - end if; - - Root_Op_Typ := Root_Type (Actual_Op_Typ); - - -- Ada 2005 (AI-251): Handle interface type conversion - - if Is_Interface (Actual_Op_Typ) then - Expand_Interface_Conversion (N, Is_Static => False); - goto Done; - end if; - - if not Tag_Checks_Suppressed (Actual_Targ_Typ) then - - -- Create a runtime tag check for a downward class-wide type - -- conversion. - - if Is_Class_Wide_Type (Actual_Op_Typ) - and then Actual_Op_Typ /= Actual_Targ_Typ - and then Root_Op_Typ /= Actual_Targ_Typ - and then Is_Ancestor (Root_Op_Typ, Actual_Targ_Typ, - Use_Full_View => True) - then - Make_Tag_Check (Class_Wide_Type (Actual_Targ_Typ)); - Make_Conversion := True; - end if; - - -- AI05-0073: If the result subtype of the function is defined - -- by an access_definition designating a specific tagged type - -- T, a check is made that the result value is null or the tag - -- of the object designated by the result value identifies T. - -- Constraint_Error is raised if this check fails. - - if Nkind (Parent (N)) = N_Simple_Return_Statement then - declare - Func : Entity_Id; - Func_Typ : Entity_Id; - - begin - -- Climb scope stack looking for the enclosing function - - Func := Current_Scope; - while Present (Func) - and then Ekind (Func) /= E_Function - loop - Func := Scope (Func); - end loop; - - -- The function's return subtype must be defined using - -- an access definition. - - if Nkind (Result_Definition (Parent (Func))) = - N_Access_Definition - then - Func_Typ := Directly_Designated_Type (Etype (Func)); - - -- The return subtype denotes a specific tagged type, - -- in other words, a non class-wide type. - - if Is_Tagged_Type (Func_Typ) - and then not Is_Class_Wide_Type (Func_Typ) - then - Make_Tag_Check (Actual_Targ_Typ); - Make_Conversion := True; - end if; - end if; - end; - end if; - - -- We have generated a tag check for either a class-wide type - -- conversion or for AI05-0073. - - if Make_Conversion then - declare - Conv : Node_Id; - begin - Conv := - Make_Unchecked_Type_Conversion (Loc, - Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), - Expression => Relocate_Node (Expression (N))); - Rewrite (N, Conv); - Analyze_And_Resolve (N, Target_Type); - end; - end if; - end if; - end Tagged_Conversion; - - -- Case of other access type conversions - - elsif Is_Access_Type (Target_Type) then - Apply_Constraint_Check (Operand, Target_Type); - - -- Case of conversions from a fixed-point type - - -- These conversions require special expansion and processing, found in - -- the Exp_Fixd package. We ignore cases where Conversion_OK is set, - -- since from a semantic point of view, these are simple integer - -- conversions, which do not need further processing. - - elsif Is_Fixed_Point_Type (Operand_Type) - and then not Conversion_OK (N) - then - -- We should never see universal fixed at this case, since the - -- expansion of the constituent divide or multiply should have - -- eliminated the explicit mention of universal fixed. - - pragma Assert (Operand_Type /= Universal_Fixed); - - -- Check for special case of the conversion to universal real that - -- occurs as a result of the use of a round attribute. In this case, - -- the real type for the conversion is taken from the target type of - -- the Round attribute and the result must be marked as rounded. - - if Target_Type = Universal_Real - and then Nkind (Parent (N)) = N_Attribute_Reference - and then Attribute_Name (Parent (N)) = Name_Round - then - Set_Rounded_Result (N); - Set_Etype (N, Etype (Parent (N))); - end if; - - -- Otherwise do correct fixed-conversion, but skip these if the - -- Conversion_OK flag is set, because from a semantic point of view - -- these are simple integer conversions needing no further processing - -- (the backend will simply treat them as integers). - - if not Conversion_OK (N) then - if Is_Fixed_Point_Type (Etype (N)) then - Expand_Convert_Fixed_To_Fixed (N); - Real_Range_Check; - - elsif Is_Integer_Type (Etype (N)) then - Expand_Convert_Fixed_To_Integer (N); - - else - pragma Assert (Is_Floating_Point_Type (Etype (N))); - Expand_Convert_Fixed_To_Float (N); - Real_Range_Check; - end if; - end if; - - -- Case of conversions to a fixed-point type - - -- These conversions require special expansion and processing, found in - -- the Exp_Fixd package. Again, ignore cases where Conversion_OK is set, - -- since from a semantic point of view, these are simple integer - -- conversions, which do not need further processing. - - elsif Is_Fixed_Point_Type (Target_Type) - and then not Conversion_OK (N) - then - if Is_Integer_Type (Operand_Type) then - Expand_Convert_Integer_To_Fixed (N); - Real_Range_Check; - else - pragma Assert (Is_Floating_Point_Type (Operand_Type)); - Expand_Convert_Float_To_Fixed (N); - Real_Range_Check; - end if; - - -- Case of float-to-integer conversions - - -- We also handle float-to-fixed conversions with Conversion_OK set - -- since semantically the fixed-point target is treated as though it - -- were an integer in such cases. - - elsif Is_Floating_Point_Type (Operand_Type) - and then - (Is_Integer_Type (Target_Type) - or else - (Is_Fixed_Point_Type (Target_Type) and then Conversion_OK (N))) - then - -- One more check here, gcc is still not able to do conversions of - -- this type with proper overflow checking, and so gigi is doing an - -- approximation of what is required by doing floating-point compares - -- with the end-point. But that can lose precision in some cases, and - -- give a wrong result. Converting the operand to Universal_Real is - -- helpful, but still does not catch all cases with 64-bit integers - -- on targets with only 64-bit floats. - - -- The above comment seems obsoleted by Apply_Float_Conversion_Check - -- Can this code be removed ??? - - if Do_Range_Check (Operand) then - Rewrite (Operand, - Make_Type_Conversion (Loc, - Subtype_Mark => - New_Occurrence_Of (Universal_Real, Loc), - Expression => - Relocate_Node (Operand))); - - Set_Etype (Operand, Universal_Real); - Enable_Range_Check (Operand); - Set_Do_Range_Check (Expression (Operand), False); - end if; - - -- Case of array conversions - - -- Expansion of array conversions, add required length/range checks but - -- only do this if there is no change of representation. For handling of - -- this case, see Handle_Changed_Representation. - - elsif Is_Array_Type (Target_Type) then - if Is_Constrained (Target_Type) then - Apply_Length_Check (Operand, Target_Type); - else - Apply_Range_Check (Operand, Target_Type); - end if; - - Handle_Changed_Representation; - - -- Case of conversions of discriminated types - - -- Add required discriminant checks if target is constrained. Again this - -- change is skipped if we have a change of representation. - - elsif Has_Discriminants (Target_Type) - and then Is_Constrained (Target_Type) - then - Apply_Discriminant_Check (Operand, Target_Type); - Handle_Changed_Representation; - - -- Case of all other record conversions. The only processing required - -- is to check for a change of representation requiring the special - -- assignment processing. - - elsif Is_Record_Type (Target_Type) then - - -- Ada 2005 (AI-216): Program_Error is raised when converting from - -- a derived Unchecked_Union type to an unconstrained type that is - -- not Unchecked_Union if the operand lacks inferable discriminants. - - if Is_Derived_Type (Operand_Type) - and then Is_Unchecked_Union (Base_Type (Operand_Type)) - and then not Is_Constrained (Target_Type) - and then not Is_Unchecked_Union (Base_Type (Target_Type)) - and then not Has_Inferable_Discriminants (Operand) - then - -- To prevent Gigi from generating illegal code, we generate a - -- Program_Error node, but we give it the target type of the - -- conversion (is this requirement documented somewhere ???) - - declare - PE : constant Node_Id := Make_Raise_Program_Error (Loc, - Reason => PE_Unchecked_Union_Restriction); - - begin - Set_Etype (PE, Target_Type); - Rewrite (N, PE); - - end; - else - Handle_Changed_Representation; - end if; - - -- Case of conversions of enumeration types - - elsif Is_Enumeration_Type (Target_Type) then - - -- Special processing is required if there is a change of - -- representation (from enumeration representation clauses). - - if not Same_Representation (Target_Type, Operand_Type) then - - -- Convert: x(y) to x'val (ytyp'val (y)) - - Rewrite (N, - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Target_Type, Loc), - Attribute_Name => Name_Val, - Expressions => New_List ( - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Operand_Type, Loc), - Attribute_Name => Name_Pos, - Expressions => New_List (Operand))))); - - Analyze_And_Resolve (N, Target_Type); - end if; - - -- Case of conversions to floating-point - - elsif Is_Floating_Point_Type (Target_Type) then - Real_Range_Check; - end if; - - -- At this stage, either the conversion node has been transformed into - -- some other equivalent expression, or left as a conversion that can be - -- handled by Gigi, in the following cases: - - -- Conversions with no change of representation or type - - -- Numeric conversions involving integer, floating- and fixed-point - -- values. Fixed-point values are allowed only if Conversion_OK is - -- set, i.e. if the fixed-point values are to be treated as integers. - - -- No other conversions should be passed to Gigi - - -- Check: are these rules stated in sinfo??? if so, why restate here??? - - -- The only remaining step is to generate a range check if we still have - -- a type conversion at this stage and Do_Range_Check is set. For now we - -- do this only for conversions of discrete types. - - if Nkind (N) = N_Type_Conversion - and then Is_Discrete_Type (Etype (N)) - then - declare - Expr : constant Node_Id := Expression (N); - Ftyp : Entity_Id; - Ityp : Entity_Id; - - begin - if Do_Range_Check (Expr) - and then Is_Discrete_Type (Etype (Expr)) - then - Set_Do_Range_Check (Expr, False); - - -- Before we do a range check, we have to deal with treating a - -- fixed-point operand as an integer. The way we do this is - -- simply to do an unchecked conversion to an appropriate - -- integer type large enough to hold the result. - - -- This code is not active yet, because we are only dealing - -- with discrete types so far ??? - - if Nkind (Expr) in N_Has_Treat_Fixed_As_Integer - and then Treat_Fixed_As_Integer (Expr) - then - Ftyp := Base_Type (Etype (Expr)); - - if Esize (Ftyp) >= Esize (Standard_Integer) then - Ityp := Standard_Long_Long_Integer; - else - Ityp := Standard_Integer; - end if; - - Rewrite (Expr, Unchecked_Convert_To (Ityp, Expr)); - end if; - - -- Reset overflow flag, since the range check will include - -- dealing with possible overflow, and generate the check. If - -- Address is either a source type or target type, suppress - -- range check to avoid typing anomalies when it is a visible - -- integer type. - - Set_Do_Overflow_Check (N, False); - if not Is_Descendent_Of_Address (Etype (Expr)) - and then not Is_Descendent_Of_Address (Target_Type) - then - Generate_Range_Check - (Expr, Target_Type, CE_Range_Check_Failed); - end if; - end if; - end; - end if; - - -- Final step, if the result is a type conversion involving Vax_Float - -- types, then it is subject for further special processing. - - if Nkind (N) = N_Type_Conversion - and then (Vax_Float (Operand_Type) or else Vax_Float (Target_Type)) - then - Expand_Vax_Conversion (N); - goto Done; - end if; - - -- Here at end of processing - - <<Done>> - -- Apply predicate check if required. Note that we can't just call - -- Apply_Predicate_Check here, because the type looks right after - -- the conversion and it would omit the check. The Comes_From_Source - -- guard is necessary to prevent infinite recursions when we generate - -- internal conversions for the purpose of checking predicates. - - if Present (Predicate_Function (Target_Type)) - and then Target_Type /= Operand_Type - and then Comes_From_Source (N) - then - declare - New_Expr : constant Node_Id := Duplicate_Subexpr (N); - - begin - -- Avoid infinite recursion on the subsequent expansion of - -- of the copy of the original type conversion. - - Set_Comes_From_Source (New_Expr, False); - Insert_Action (N, Make_Predicate_Check (Target_Type, New_Expr)); - end; - end if; - end Expand_N_Type_Conversion; - - ----------------------------------- - -- Expand_N_Unchecked_Expression -- - ----------------------------------- - - -- Remove the unchecked expression node from the tree. Its job was simply - -- to make sure that its constituent expression was handled with checks - -- off, and now that that is done, we can remove it from the tree, and - -- indeed must, since Gigi does not expect to see these nodes. - - procedure Expand_N_Unchecked_Expression (N : Node_Id) is - Exp : constant Node_Id := Expression (N); - begin - Set_Assignment_OK (Exp, Assignment_OK (N) or else Assignment_OK (Exp)); - Rewrite (N, Exp); - end Expand_N_Unchecked_Expression; - - ---------------------------------------- - -- Expand_N_Unchecked_Type_Conversion -- - ---------------------------------------- - - -- If this cannot be handled by Gigi and we haven't already made a - -- temporary for it, do it now. - - procedure Expand_N_Unchecked_Type_Conversion (N : Node_Id) is - Target_Type : constant Entity_Id := Etype (N); - Operand : constant Node_Id := Expression (N); - Operand_Type : constant Entity_Id := Etype (Operand); - - begin - -- Nothing at all to do if conversion is to the identical type so remove - -- the conversion completely, it is useless, except that it may carry - -- an Assignment_OK indication which must be propagated to the operand. - - if Operand_Type = Target_Type then - - -- Code duplicates Expand_N_Unchecked_Expression above, factor??? - - if Assignment_OK (N) then - Set_Assignment_OK (Operand); - end if; - - Rewrite (N, Relocate_Node (Operand)); - return; - end if; - - -- If we have a conversion of a compile time known value to a target - -- type and the value is in range of the target type, then we can simply - -- replace the construct by an integer literal of the correct type. We - -- only apply this to integer types being converted. Possibly it may - -- apply in other cases, but it is too much trouble to worry about. - - -- Note that we do not do this transformation if the Kill_Range_Check - -- flag is set, since then the value may be outside the expected range. - -- This happens in the Normalize_Scalars case. - - -- We also skip this if either the target or operand type is biased - -- because in this case, the unchecked conversion is supposed to - -- preserve the bit pattern, not the integer value. - - if Is_Integer_Type (Target_Type) - and then not Has_Biased_Representation (Target_Type) - and then Is_Integer_Type (Operand_Type) - and then not Has_Biased_Representation (Operand_Type) - and then Compile_Time_Known_Value (Operand) - and then not Kill_Range_Check (N) - then - declare - Val : constant Uint := Expr_Value (Operand); - - begin - if Compile_Time_Known_Value (Type_Low_Bound (Target_Type)) - and then - Compile_Time_Known_Value (Type_High_Bound (Target_Type)) - and then - Val >= Expr_Value (Type_Low_Bound (Target_Type)) - and then - Val <= Expr_Value (Type_High_Bound (Target_Type)) - then - Rewrite (N, Make_Integer_Literal (Sloc (N), Val)); - - -- If Address is the target type, just set the type to avoid a - -- spurious type error on the literal when Address is a visible - -- integer type. - - if Is_Descendent_Of_Address (Target_Type) then - Set_Etype (N, Target_Type); - else - Analyze_And_Resolve (N, Target_Type); - end if; - - return; - end if; - end; - end if; - - -- Nothing to do if conversion is safe - - if Safe_Unchecked_Type_Conversion (N) then - return; - end if; - - -- Otherwise force evaluation unless Assignment_OK flag is set (this - -- flag indicates ??? More comments needed here) - - if Assignment_OK (N) then - null; - else - Force_Evaluation (N); - end if; - end Expand_N_Unchecked_Type_Conversion; - - ---------------------------- - -- Expand_Record_Equality -- - ---------------------------- - - -- For non-variant records, Equality is expanded when needed into: - - -- and then Lhs.Discr1 = Rhs.Discr1 - -- and then ... - -- and then Lhs.Discrn = Rhs.Discrn - -- and then Lhs.Cmp1 = Rhs.Cmp1 - -- and then ... - -- and then Lhs.Cmpn = Rhs.Cmpn - - -- The expression is folded by the back-end for adjacent fields. This - -- function is called for tagged record in only one occasion: for imple- - -- menting predefined primitive equality (see Predefined_Primitives_Bodies) - -- otherwise the primitive "=" is used directly. - - function Expand_Record_Equality - (Nod : Node_Id; - Typ : Entity_Id; - Lhs : Node_Id; - Rhs : Node_Id; - Bodies : List_Id) return Node_Id - is - Loc : constant Source_Ptr := Sloc (Nod); - - Result : Node_Id; - C : Entity_Id; - - First_Time : Boolean := True; - - function Suitable_Element (C : Entity_Id) return Entity_Id; - -- Return the first field to compare beginning with C, skipping the - -- inherited components. - - ---------------------- - -- Suitable_Element -- - ---------------------- - - function Suitable_Element (C : Entity_Id) return Entity_Id is - begin - if No (C) then - return Empty; - - elsif Ekind (C) /= E_Discriminant - and then Ekind (C) /= E_Component - then - return Suitable_Element (Next_Entity (C)); - - -- Below test for C /= Original_Record_Component (C) is dubious - -- if Typ is a constrained record subtype??? - - elsif Is_Tagged_Type (Typ) - and then C /= Original_Record_Component (C) - then - return Suitable_Element (Next_Entity (C)); - - elsif Chars (C) = Name_uTag then - return Suitable_Element (Next_Entity (C)); - - -- The .NET/JVM version of type Root_Controlled contains two fields - -- which should not be considered part of the object. To achieve - -- proper equiality between two controlled objects on .NET/JVM, skip - -- field _parent whenever it is of type Root_Controlled. - - elsif Chars (C) = Name_uParent - and then VM_Target /= No_VM - and then Etype (C) = RTE (RE_Root_Controlled) - then - return Suitable_Element (Next_Entity (C)); - - elsif Is_Interface (Etype (C)) then - return Suitable_Element (Next_Entity (C)); - - else - return C; - end if; - end Suitable_Element; - - -- Start of processing for Expand_Record_Equality - - begin - -- Generates the following code: (assuming that Typ has one Discr and - -- component C2 is also a record) - - -- True - -- and then Lhs.Discr1 = Rhs.Discr1 - -- and then Lhs.C1 = Rhs.C1 - -- and then Lhs.C2.C1=Rhs.C2.C1 and then ... Lhs.C2.Cn=Rhs.C2.Cn - -- and then ... - -- and then Lhs.Cmpn = Rhs.Cmpn - - Result := New_Reference_To (Standard_True, Loc); - C := Suitable_Element (First_Entity (Typ)); - while Present (C) loop - declare - New_Lhs : Node_Id; - New_Rhs : Node_Id; - Check : Node_Id; - - begin - if First_Time then - First_Time := False; - New_Lhs := Lhs; - New_Rhs := Rhs; - else - New_Lhs := New_Copy_Tree (Lhs); - New_Rhs := New_Copy_Tree (Rhs); - end if; - - Check := - Expand_Composite_Equality (Nod, Etype (C), - Lhs => - Make_Selected_Component (Loc, - Prefix => New_Lhs, - Selector_Name => New_Reference_To (C, Loc)), - Rhs => - Make_Selected_Component (Loc, - Prefix => New_Rhs, - Selector_Name => New_Reference_To (C, Loc)), - Bodies => Bodies); - - -- If some (sub)component is an unchecked_union, the whole - -- operation will raise program error. - - if Nkind (Check) = N_Raise_Program_Error then - Result := Check; - Set_Etype (Result, Standard_Boolean); - exit; - else - Result := - Make_And_Then (Loc, - Left_Opnd => Result, - Right_Opnd => Check); - end if; - end; - - C := Suitable_Element (Next_Entity (C)); - end loop; - - return Result; - end Expand_Record_Equality; - - --------------------------- - -- Expand_Set_Membership -- - --------------------------- - - procedure Expand_Set_Membership (N : Node_Id) is - Lop : constant Node_Id := Left_Opnd (N); - Alt : Node_Id; - Res : Node_Id; - - function Make_Cond (Alt : Node_Id) return Node_Id; - -- If the alternative is a subtype mark, create a simple membership - -- test. Otherwise create an equality test for it. - - --------------- - -- Make_Cond -- - --------------- - - function Make_Cond (Alt : Node_Id) return Node_Id is - Cond : Node_Id; - L : constant Node_Id := New_Copy (Lop); - R : constant Node_Id := Relocate_Node (Alt); - - begin - if (Is_Entity_Name (Alt) and then Is_Type (Entity (Alt))) - or else Nkind (Alt) = N_Range - then - Cond := - Make_In (Sloc (Alt), - Left_Opnd => L, - Right_Opnd => R); - else - Cond := - Make_Op_Eq (Sloc (Alt), - Left_Opnd => L, - Right_Opnd => R); - end if; - - return Cond; - end Make_Cond; - - -- Start of processing for Expand_Set_Membership - - begin - Remove_Side_Effects (Lop); - - Alt := Last (Alternatives (N)); - Res := Make_Cond (Alt); - - Prev (Alt); - while Present (Alt) loop - Res := - Make_Or_Else (Sloc (Alt), - Left_Opnd => Make_Cond (Alt), - Right_Opnd => Res); - Prev (Alt); - end loop; - - Rewrite (N, Res); - Analyze_And_Resolve (N, Standard_Boolean); - end Expand_Set_Membership; - - ----------------------------------- - -- Expand_Short_Circuit_Operator -- - ----------------------------------- - - -- Deal with special expansion if actions are present for the right operand - -- and deal with optimizing case of arguments being True or False. We also - -- deal with the special case of non-standard boolean values. - - procedure Expand_Short_Circuit_Operator (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Left : constant Node_Id := Left_Opnd (N); - Right : constant Node_Id := Right_Opnd (N); - LocR : constant Source_Ptr := Sloc (Right); - Actlist : List_Id; - - Shortcut_Value : constant Boolean := Nkind (N) = N_Or_Else; - Shortcut_Ent : constant Entity_Id := Boolean_Literals (Shortcut_Value); - -- If Left = Shortcut_Value then Right need not be evaluated - - function Make_Test_Expr (Opnd : Node_Id) return Node_Id; - -- For Opnd a boolean expression, return a Boolean expression equivalent - -- to Opnd /= Shortcut_Value. - - -------------------- - -- Make_Test_Expr -- - -------------------- - - function Make_Test_Expr (Opnd : Node_Id) return Node_Id is - begin - if Shortcut_Value then - return Make_Op_Not (Sloc (Opnd), Opnd); - else - return Opnd; - end if; - end Make_Test_Expr; - - Op_Var : Entity_Id; - -- Entity for a temporary variable holding the value of the operator, - -- used for expansion in the case where actions are present. - - -- Start of processing for Expand_Short_Circuit_Operator - - begin - -- Deal with non-standard booleans - - if Is_Boolean_Type (Typ) then - Adjust_Condition (Left); - Adjust_Condition (Right); - Set_Etype (N, Standard_Boolean); - end if; - - -- Check for cases where left argument is known to be True or False - - if Compile_Time_Known_Value (Left) then - - -- Mark SCO for left condition as compile time known - - if Generate_SCO and then Comes_From_Source (Left) then - Set_SCO_Condition (Left, Expr_Value_E (Left) = Standard_True); - end if; - - -- Rewrite True AND THEN Right / False OR ELSE Right to Right. - -- Any actions associated with Right will be executed unconditionally - -- and can thus be inserted into the tree unconditionally. - - if Expr_Value_E (Left) /= Shortcut_Ent then - if Present (Actions (N)) then - Insert_Actions (N, Actions (N)); - end if; - - Rewrite (N, Right); - - -- Rewrite False AND THEN Right / True OR ELSE Right to Left. - -- In this case we can forget the actions associated with Right, - -- since they will never be executed. - - else - Kill_Dead_Code (Right); - Kill_Dead_Code (Actions (N)); - Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); - end if; - - Adjust_Result_Type (N, Typ); - return; - end if; - - -- If Actions are present for the right operand, we have to do some - -- special processing. We can't just let these actions filter back into - -- code preceding the short circuit (which is what would have happened - -- if we had not trapped them in the short-circuit form), since they - -- must only be executed if the right operand of the short circuit is - -- executed and not otherwise. - - -- the temporary variable C. - - if Present (Actions (N)) then - Actlist := Actions (N); - - -- The old approach is to expand: - - -- left AND THEN right - - -- into - - -- C : Boolean := False; - -- IF left THEN - -- Actions; - -- IF right THEN - -- C := True; - -- END IF; - -- END IF; - - -- and finally rewrite the operator into a reference to C. Similarly - -- for left OR ELSE right, with negated values. Note that this - -- rewrite causes some difficulties for coverage analysis because - -- of the introduction of the new variable C, which obscures the - -- structure of the test. - - -- We use this "old approach" if use of N_Expression_With_Actions - -- is False (see description in Opt of when this is or is not set). - - if not Use_Expression_With_Actions then - Op_Var := Make_Temporary (Loc, 'C', Related_Node => N); - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => - Op_Var, - Object_Definition => - New_Occurrence_Of (Standard_Boolean, Loc), - Expression => - New_Occurrence_Of (Shortcut_Ent, Loc))); - - Append_To (Actlist, - Make_Implicit_If_Statement (Right, - Condition => Make_Test_Expr (Right), - Then_Statements => New_List ( - Make_Assignment_Statement (LocR, - Name => New_Occurrence_Of (Op_Var, LocR), - Expression => - New_Occurrence_Of - (Boolean_Literals (not Shortcut_Value), LocR))))); - - Insert_Action (N, - Make_Implicit_If_Statement (Left, - Condition => Make_Test_Expr (Left), - Then_Statements => Actlist)); - - Rewrite (N, New_Occurrence_Of (Op_Var, Loc)); - Analyze_And_Resolve (N, Standard_Boolean); - - -- The new approach, activated for now by the use of debug flag - -- -gnatd.X is to use the new Expression_With_Actions node for the - -- right operand of the short-circuit form. This should solve the - -- traceability problems for coverage analysis. - - else - Rewrite (Right, - Make_Expression_With_Actions (LocR, - Expression => Relocate_Node (Right), - Actions => Actlist)); - Set_Actions (N, No_List); - Analyze_And_Resolve (Right, Standard_Boolean); - end if; - - Adjust_Result_Type (N, Typ); - return; - end if; - - -- No actions present, check for cases of right argument True/False - - if Compile_Time_Known_Value (Right) then - - -- Mark SCO for left condition as compile time known - - if Generate_SCO and then Comes_From_Source (Right) then - Set_SCO_Condition (Right, Expr_Value_E (Right) = Standard_True); - end if; - - -- Change (Left and then True), (Left or else False) to Left. - -- Note that we know there are no actions associated with the right - -- operand, since we just checked for this case above. - - if Expr_Value_E (Right) /= Shortcut_Ent then - Rewrite (N, Left); - - -- Change (Left and then False), (Left or else True) to Right, - -- making sure to preserve any side effects associated with the Left - -- operand. - - else - Remove_Side_Effects (Left); - Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); - end if; - end if; - - Adjust_Result_Type (N, Typ); - end Expand_Short_Circuit_Operator; - - ------------------------------------- - -- Fixup_Universal_Fixed_Operation -- - ------------------------------------- - - procedure Fixup_Universal_Fixed_Operation (N : Node_Id) is - Conv : constant Node_Id := Parent (N); - - begin - -- We must have a type conversion immediately above us - - pragma Assert (Nkind (Conv) = N_Type_Conversion); - - -- Normally the type conversion gives our target type. The exception - -- occurs in the case of the Round attribute, where the conversion - -- will be to universal real, and our real type comes from the Round - -- attribute (as well as an indication that we must round the result) - - if Nkind (Parent (Conv)) = N_Attribute_Reference - and then Attribute_Name (Parent (Conv)) = Name_Round - then - Set_Etype (N, Etype (Parent (Conv))); - Set_Rounded_Result (N); - - -- Normal case where type comes from conversion above us - - else - Set_Etype (N, Etype (Conv)); - end if; - end Fixup_Universal_Fixed_Operation; - - --------------------------------- - -- Has_Inferable_Discriminants -- - --------------------------------- - - function Has_Inferable_Discriminants (N : Node_Id) return Boolean is - - function Prefix_Is_Formal_Parameter (N : Node_Id) return Boolean; - -- Determines whether the left-most prefix of a selected component is a - -- formal parameter in a subprogram. Assumes N is a selected component. - - -------------------------------- - -- Prefix_Is_Formal_Parameter -- - -------------------------------- - - function Prefix_Is_Formal_Parameter (N : Node_Id) return Boolean is - Sel_Comp : Node_Id; - - begin - -- Move to the left-most prefix by climbing up the tree - - Sel_Comp := N; - while Present (Parent (Sel_Comp)) - and then Nkind (Parent (Sel_Comp)) = N_Selected_Component - loop - Sel_Comp := Parent (Sel_Comp); - end loop; - - return Ekind (Entity (Prefix (Sel_Comp))) in Formal_Kind; - end Prefix_Is_Formal_Parameter; - - -- Start of processing for Has_Inferable_Discriminants - - begin - -- For selected components, the subtype of the selector must be a - -- constrained Unchecked_Union. If the component is subject to a - -- per-object constraint, then the enclosing object must have inferable - -- discriminants. - - if Nkind (N) = N_Selected_Component then - if Has_Per_Object_Constraint (Entity (Selector_Name (N))) then - - -- A small hack. If we have a per-object constrained selected - -- component of a formal parameter, return True since we do not - -- know the actual parameter association yet. - - if Prefix_Is_Formal_Parameter (N) then - return True; - - -- Otherwise, check the enclosing object and the selector - - else - return Has_Inferable_Discriminants (Prefix (N)) - and then Has_Inferable_Discriminants (Selector_Name (N)); - end if; - - -- The call to Has_Inferable_Discriminants will determine whether - -- the selector has a constrained Unchecked_Union nominal type. - - else - return Has_Inferable_Discriminants (Selector_Name (N)); - end if; - - -- A qualified expression has inferable discriminants if its subtype - -- mark is a constrained Unchecked_Union subtype. - - elsif Nkind (N) = N_Qualified_Expression then - return Is_Unchecked_Union (Etype (Subtype_Mark (N))) - and then Is_Constrained (Etype (Subtype_Mark (N))); - - -- For all other names, it is sufficient to have a constrained - -- Unchecked_Union nominal subtype. - - else - return Is_Unchecked_Union (Base_Type (Etype (N))) - and then Is_Constrained (Etype (N)); - end if; - end Has_Inferable_Discriminants; - - ------------------------------- - -- Insert_Dereference_Action -- - ------------------------------- - - procedure Insert_Dereference_Action (N : Node_Id) is - - function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean; - -- Return true if type of P is derived from Checked_Pool; - - ----------------------------- - -- Is_Checked_Storage_Pool -- - ----------------------------- - - function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean is - T : Entity_Id; - - begin - if No (P) then - return False; - end if; - - T := Etype (P); - while T /= Etype (T) loop - if Is_RTE (T, RE_Checked_Pool) then - return True; - else - T := Etype (T); - end if; - end loop; - - return False; - end Is_Checked_Storage_Pool; - - -- Local variables - - Typ : constant Entity_Id := Etype (N); - Desig : constant Entity_Id := Available_View (Designated_Type (Typ)); - Loc : constant Source_Ptr := Sloc (N); - Pool : constant Entity_Id := Associated_Storage_Pool (Typ); - Pnod : constant Node_Id := Parent (N); - - Addr : Entity_Id; - Alig : Entity_Id; - Deref : Node_Id; - Size : Entity_Id; - Stmt : Node_Id; - - -- Start of processing for Insert_Dereference_Action - - begin - pragma Assert (Nkind (Pnod) = N_Explicit_Dereference); - - -- Do not re-expand a dereference which has already been processed by - -- this routine. - - if Has_Dereference_Action (Pnod) then - return; - - -- Do not perform this type of expansion for internally-generated - -- dereferences. - - elsif not Comes_From_Source (Original_Node (Pnod)) then - return; - - -- A dereference action is only applicable to objects which have been - -- allocated on a checked pool. - - elsif not Is_Checked_Storage_Pool (Pool) then - return; - end if; - - -- Extract the address of the dereferenced object. Generate: - - -- Addr : System.Address := <N>'Pool_Address; - - Addr := Make_Temporary (Loc, 'P'); - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => Addr, - Object_Definition => - New_Reference_To (RTE (RE_Address), Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => Duplicate_Subexpr_Move_Checks (N), - Attribute_Name => Name_Pool_Address))); - - -- Calculate the size of the dereferenced object. Generate: - - -- Size : Storage_Count := <N>.all'Size / Storage_Unit; - - Deref := - Make_Explicit_Dereference (Loc, - Prefix => Duplicate_Subexpr_Move_Checks (N)); - Set_Has_Dereference_Action (Deref); - - Size := Make_Temporary (Loc, 'S'); - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => Size, - - Object_Definition => - New_Reference_To (RTE (RE_Storage_Count), Loc), - - Expression => - Make_Op_Divide (Loc, - Left_Opnd => - Make_Attribute_Reference (Loc, - Prefix => Deref, - Attribute_Name => Name_Size), - Right_Opnd => - Make_Integer_Literal (Loc, System_Storage_Unit)))); - - -- Calculate the alignment of the dereferenced object. Generate: - -- Alig : constant Storage_Count := <N>.all'Alignment; - - Deref := - Make_Explicit_Dereference (Loc, - Prefix => Duplicate_Subexpr_Move_Checks (N)); - Set_Has_Dereference_Action (Deref); - - Alig := Make_Temporary (Loc, 'A'); - - Insert_Action (N, - Make_Object_Declaration (Loc, - Defining_Identifier => Alig, - Object_Definition => - New_Reference_To (RTE (RE_Storage_Count), Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => Deref, - Attribute_Name => Name_Alignment))); - - -- A dereference of a controlled object requires special processing. The - -- finalization machinery requests additional space from the underlying - -- pool to allocate and hide two pointers. As a result, a checked pool - -- may mark the wrong memory as valid. Since checked pools do not have - -- knowledge of hidden pointers, we have to bring the two pointers back - -- in view in order to restore the original state of the object. - - if Needs_Finalization (Desig) then - - -- Adjust the address and size of the dereferenced object. Generate: - -- Adjust_Controlled_Dereference (Addr, Size, Alig); - - Stmt := - Make_Procedure_Call_Statement (Loc, - Name => - New_Reference_To (RTE (RE_Adjust_Controlled_Dereference), Loc), - Parameter_Associations => New_List ( - New_Reference_To (Addr, Loc), - New_Reference_To (Size, Loc), - New_Reference_To (Alig, Loc))); - - -- Class-wide types complicate things because we cannot determine - -- statically whether the actual object is truly controlled. We must - -- generate a runtime check to detect this property. Generate: - -- - -- if Needs_Finalization (<N>.all'Tag) then - -- <Stmt>; - -- end if; - - if Is_Class_Wide_Type (Desig) then - Deref := - Make_Explicit_Dereference (Loc, - Prefix => Duplicate_Subexpr_Move_Checks (N)); - Set_Has_Dereference_Action (Deref); - - Stmt := - Make_If_Statement (Loc, - Condition => - Make_Function_Call (Loc, - Name => - New_Reference_To (RTE (RE_Needs_Finalization), Loc), - Parameter_Associations => New_List ( - Make_Attribute_Reference (Loc, - Prefix => Deref, - Attribute_Name => Name_Tag))), - Then_Statements => New_List (Stmt)); - end if; - - Insert_Action (N, Stmt); - end if; - - -- Generate: - -- Dereference (Pool, Addr, Size, Alig); - - Insert_Action (N, - Make_Procedure_Call_Statement (Loc, - Name => - New_Reference_To - (Find_Prim_Op (Etype (Pool), Name_Dereference), Loc), - Parameter_Associations => New_List ( - New_Reference_To (Pool, Loc), - New_Reference_To (Addr, Loc), - New_Reference_To (Size, Loc), - New_Reference_To (Alig, Loc)))); - - -- Mark the explicit dereference as processed to avoid potential - -- infinite expansion. - - Set_Has_Dereference_Action (Pnod); - - exception - when RE_Not_Available => - return; - end Insert_Dereference_Action; - - -------------------------------- - -- Integer_Promotion_Possible -- - -------------------------------- - - function Integer_Promotion_Possible (N : Node_Id) return Boolean is - Operand : constant Node_Id := Expression (N); - Operand_Type : constant Entity_Id := Etype (Operand); - Root_Operand_Type : constant Entity_Id := Root_Type (Operand_Type); - - begin - pragma Assert (Nkind (N) = N_Type_Conversion); - - return - - -- We only do the transformation for source constructs. We assume - -- that the expander knows what it is doing when it generates code. - - Comes_From_Source (N) - - -- If the operand type is Short_Integer or Short_Short_Integer, - -- then we will promote to Integer, which is available on all - -- targets, and is sufficient to ensure no intermediate overflow. - -- Furthermore it is likely to be as efficient or more efficient - -- than using the smaller type for the computation so we do this - -- unconditionally. - - and then - (Root_Operand_Type = Base_Type (Standard_Short_Integer) - or else - Root_Operand_Type = Base_Type (Standard_Short_Short_Integer)) - - -- Test for interesting operation, which includes addition, - -- division, exponentiation, multiplication, subtraction, absolute - -- value and unary negation. Unary "+" is omitted since it is a - -- no-op and thus can't overflow. - - and then Nkind_In (Operand, N_Op_Abs, - N_Op_Add, - N_Op_Divide, - N_Op_Expon, - N_Op_Minus, - N_Op_Multiply, - N_Op_Subtract); - end Integer_Promotion_Possible; - - ------------------------------ - -- Make_Array_Comparison_Op -- - ------------------------------ - - -- This is a hand-coded expansion of the following generic function: - - -- generic - -- type elem is (<>); - -- type index is (<>); - -- type a is array (index range <>) of elem; - - -- function Gnnn (X : a; Y: a) return boolean is - -- J : index := Y'first; - - -- begin - -- if X'length = 0 then - -- return false; - - -- elsif Y'length = 0 then - -- return true; - - -- else - -- for I in X'range loop - -- if X (I) = Y (J) then - -- if J = Y'last then - -- exit; - -- else - -- J := index'succ (J); - -- end if; - - -- else - -- return X (I) > Y (J); - -- end if; - -- end loop; - - -- return X'length > Y'length; - -- end if; - -- end Gnnn; - - -- Note that since we are essentially doing this expansion by hand, we - -- do not need to generate an actual or formal generic part, just the - -- instantiated function itself. - - function Make_Array_Comparison_Op - (Typ : Entity_Id; - Nod : Node_Id) return Node_Id - is - Loc : constant Source_Ptr := Sloc (Nod); - - X : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uX); - Y : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uY); - I : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uI); - J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); - - Index : constant Entity_Id := Base_Type (Etype (First_Index (Typ))); - - Loop_Statement : Node_Id; - Loop_Body : Node_Id; - If_Stat : Node_Id; - Inner_If : Node_Id; - Final_Expr : Node_Id; - Func_Body : Node_Id; - Func_Name : Entity_Id; - Formals : List_Id; - Length1 : Node_Id; - Length2 : Node_Id; - - begin - -- if J = Y'last then - -- exit; - -- else - -- J := index'succ (J); - -- end if; - - Inner_If := - Make_Implicit_If_Statement (Nod, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => New_Reference_To (J, Loc), - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Y, Loc), - Attribute_Name => Name_Last)), - - Then_Statements => New_List ( - Make_Exit_Statement (Loc)), - - Else_Statements => - New_List ( - Make_Assignment_Statement (Loc, - Name => New_Reference_To (J, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Index, Loc), - Attribute_Name => Name_Succ, - Expressions => New_List (New_Reference_To (J, Loc)))))); - - -- if X (I) = Y (J) then - -- if ... end if; - -- else - -- return X (I) > Y (J); - -- end if; - - Loop_Body := - Make_Implicit_If_Statement (Nod, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (X, Loc), - Expressions => New_List (New_Reference_To (I, Loc))), - - Right_Opnd => - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (Y, Loc), - Expressions => New_List (New_Reference_To (J, Loc)))), - - Then_Statements => New_List (Inner_If), - - Else_Statements => New_List ( - Make_Simple_Return_Statement (Loc, - Expression => - Make_Op_Gt (Loc, - Left_Opnd => - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (X, Loc), - Expressions => New_List (New_Reference_To (I, Loc))), - - Right_Opnd => - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (Y, Loc), - Expressions => New_List ( - New_Reference_To (J, Loc))))))); - - -- for I in X'range loop - -- if ... end if; - -- end loop; - - Loop_Statement := - Make_Implicit_Loop_Statement (Nod, - Identifier => Empty, - - Iteration_Scheme => - Make_Iteration_Scheme (Loc, - Loop_Parameter_Specification => - Make_Loop_Parameter_Specification (Loc, - Defining_Identifier => I, - Discrete_Subtype_Definition => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (X, Loc), - Attribute_Name => Name_Range))), - - Statements => New_List (Loop_Body)); - - -- if X'length = 0 then - -- return false; - -- elsif Y'length = 0 then - -- return true; - -- else - -- for ... loop ... end loop; - -- return X'length > Y'length; - -- end if; - - Length1 := - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (X, Loc), - Attribute_Name => Name_Length); - - Length2 := - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Y, Loc), - Attribute_Name => Name_Length); - - Final_Expr := - Make_Op_Gt (Loc, - Left_Opnd => Length1, - Right_Opnd => Length2); - - If_Stat := - Make_Implicit_If_Statement (Nod, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (X, Loc), - Attribute_Name => Name_Length), - Right_Opnd => - Make_Integer_Literal (Loc, 0)), - - Then_Statements => - New_List ( - Make_Simple_Return_Statement (Loc, - Expression => New_Reference_To (Standard_False, Loc))), - - Elsif_Parts => New_List ( - Make_Elsif_Part (Loc, - Condition => - Make_Op_Eq (Loc, - Left_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Y, Loc), - Attribute_Name => Name_Length), - Right_Opnd => - Make_Integer_Literal (Loc, 0)), - - Then_Statements => - New_List ( - Make_Simple_Return_Statement (Loc, - Expression => New_Reference_To (Standard_True, Loc))))), - - Else_Statements => New_List ( - Loop_Statement, - Make_Simple_Return_Statement (Loc, - Expression => Final_Expr))); - - -- (X : a; Y: a) - - Formals := New_List ( - Make_Parameter_Specification (Loc, - Defining_Identifier => X, - Parameter_Type => New_Reference_To (Typ, Loc)), - - Make_Parameter_Specification (Loc, - Defining_Identifier => Y, - Parameter_Type => New_Reference_To (Typ, Loc))); - - -- function Gnnn (...) return boolean is - -- J : index := Y'first; - -- begin - -- if ... end if; - -- end Gnnn; - - Func_Name := Make_Temporary (Loc, 'G'); - - Func_Body := - Make_Subprogram_Body (Loc, - Specification => - Make_Function_Specification (Loc, - Defining_Unit_Name => Func_Name, - Parameter_Specifications => Formals, - Result_Definition => New_Reference_To (Standard_Boolean, Loc)), - - Declarations => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => J, - Object_Definition => New_Reference_To (Index, Loc), - Expression => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Y, Loc), - Attribute_Name => Name_First))), - - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List (If_Stat))); - - return Func_Body; - end Make_Array_Comparison_Op; - - --------------------------- - -- Make_Boolean_Array_Op -- - --------------------------- - - -- For logical operations on boolean arrays, expand in line the following, - -- replacing 'and' with 'or' or 'xor' where needed: - - -- function Annn (A : typ; B: typ) return typ is - -- C : typ; - -- begin - -- for J in A'range loop - -- C (J) := A (J) op B (J); - -- end loop; - -- return C; - -- end Annn; - - -- Here typ is the boolean array type - - function Make_Boolean_Array_Op - (Typ : Entity_Id; - N : Node_Id) return Node_Id - is - Loc : constant Source_Ptr := Sloc (N); - - A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); - B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); - C : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uC); - J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); - - A_J : Node_Id; - B_J : Node_Id; - C_J : Node_Id; - Op : Node_Id; - - Formals : List_Id; - Func_Name : Entity_Id; - Func_Body : Node_Id; - Loop_Statement : Node_Id; - - begin - A_J := - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (A, Loc), - Expressions => New_List (New_Reference_To (J, Loc))); - - B_J := - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (B, Loc), - Expressions => New_List (New_Reference_To (J, Loc))); - - C_J := - Make_Indexed_Component (Loc, - Prefix => New_Reference_To (C, Loc), - Expressions => New_List (New_Reference_To (J, Loc))); - - if Nkind (N) = N_Op_And then - Op := - Make_Op_And (Loc, - Left_Opnd => A_J, - Right_Opnd => B_J); - - elsif Nkind (N) = N_Op_Or then - Op := - Make_Op_Or (Loc, - Left_Opnd => A_J, - Right_Opnd => B_J); - - else - Op := - Make_Op_Xor (Loc, - Left_Opnd => A_J, - Right_Opnd => B_J); - end if; - - Loop_Statement := - Make_Implicit_Loop_Statement (N, - Identifier => Empty, - - Iteration_Scheme => - Make_Iteration_Scheme (Loc, - Loop_Parameter_Specification => - Make_Loop_Parameter_Specification (Loc, - Defining_Identifier => J, - Discrete_Subtype_Definition => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (A, Loc), - Attribute_Name => Name_Range))), - - Statements => New_List ( - Make_Assignment_Statement (Loc, - Name => C_J, - Expression => Op))); - - Formals := New_List ( - Make_Parameter_Specification (Loc, - Defining_Identifier => A, - Parameter_Type => New_Reference_To (Typ, Loc)), - - Make_Parameter_Specification (Loc, - Defining_Identifier => B, - Parameter_Type => New_Reference_To (Typ, Loc))); - - Func_Name := Make_Temporary (Loc, 'A'); - Set_Is_Inlined (Func_Name); - - Func_Body := - Make_Subprogram_Body (Loc, - Specification => - Make_Function_Specification (Loc, - Defining_Unit_Name => Func_Name, - Parameter_Specifications => Formals, - Result_Definition => New_Reference_To (Typ, Loc)), - - Declarations => New_List ( - Make_Object_Declaration (Loc, - Defining_Identifier => C, - Object_Definition => New_Reference_To (Typ, Loc))), - - Handled_Statement_Sequence => - Make_Handled_Sequence_Of_Statements (Loc, - Statements => New_List ( - Loop_Statement, - Make_Simple_Return_Statement (Loc, - Expression => New_Reference_To (C, Loc))))); - - return Func_Body; - end Make_Boolean_Array_Op; - - ----------------------------------------- - -- Minimized_Eliminated_Overflow_Check -- - ----------------------------------------- - - function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean is - begin - return - Is_Signed_Integer_Type (Etype (N)) - and then Overflow_Check_Mode in Minimized_Or_Eliminated; - end Minimized_Eliminated_Overflow_Check; - - -------------------------------- - -- Optimize_Length_Comparison -- - -------------------------------- - - procedure Optimize_Length_Comparison (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); - Typ : constant Entity_Id := Etype (N); - Result : Node_Id; - - Left : Node_Id; - Right : Node_Id; - -- First and Last attribute reference nodes, which end up as left and - -- right operands of the optimized result. - - Is_Zero : Boolean; - -- True for comparison operand of zero - - Comp : Node_Id; - -- Comparison operand, set only if Is_Zero is false - - Ent : Entity_Id; - -- Entity whose length is being compared - - Index : Node_Id; - -- Integer_Literal node for length attribute expression, or Empty - -- if there is no such expression present. - - Ityp : Entity_Id; - -- Type of array index to which 'Length is applied - - Op : Node_Kind := Nkind (N); - -- Kind of comparison operator, gets flipped if operands backwards - - function Is_Optimizable (N : Node_Id) return Boolean; - -- Tests N to see if it is an optimizable comparison value (defined as - -- constant zero or one, or something else where the value is known to - -- be positive and in the range of 32-bits, and where the corresponding - -- Length value is also known to be 32-bits. If result is true, sets - -- Is_Zero, Ityp, and Comp accordingly. - - function Is_Entity_Length (N : Node_Id) return Boolean; - -- Tests if N is a length attribute applied to a simple entity. If so, - -- returns True, and sets Ent to the entity, and Index to the integer - -- literal provided as an attribute expression, or to Empty if none. - -- Also returns True if the expression is a generated type conversion - -- whose expression is of the desired form. This latter case arises - -- when Apply_Universal_Integer_Attribute_Check installs a conversion - -- to check for being in range, which is not needed in this context. - -- Returns False if neither condition holds. - - function Prepare_64 (N : Node_Id) return Node_Id; - -- Given a discrete expression, returns a Long_Long_Integer typed - -- expression representing the underlying value of the expression. - -- This is done with an unchecked conversion to the result type. We - -- use unchecked conversion to handle the enumeration type case. - - ---------------------- - -- Is_Entity_Length -- - ---------------------- - - function Is_Entity_Length (N : Node_Id) return Boolean is - begin - if Nkind (N) = N_Attribute_Reference - and then Attribute_Name (N) = Name_Length - and then Is_Entity_Name (Prefix (N)) - then - Ent := Entity (Prefix (N)); - - if Present (Expressions (N)) then - Index := First (Expressions (N)); - else - Index := Empty; - end if; - - return True; - - elsif Nkind (N) = N_Type_Conversion - and then not Comes_From_Source (N) - then - return Is_Entity_Length (Expression (N)); - - else - return False; - end if; - end Is_Entity_Length; - - -------------------- - -- Is_Optimizable -- - -------------------- - - function Is_Optimizable (N : Node_Id) return Boolean is - Val : Uint; - OK : Boolean; - Lo : Uint; - Hi : Uint; - Indx : Node_Id; - - begin - if Compile_Time_Known_Value (N) then - Val := Expr_Value (N); - - if Val = Uint_0 then - Is_Zero := True; - Comp := Empty; - return True; - - elsif Val = Uint_1 then - Is_Zero := False; - Comp := Empty; - return True; - end if; - end if; - - -- Here we have to make sure of being within 32-bits - - Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); - - if not OK - or else Lo < Uint_1 - or else Hi > UI_From_Int (Int'Last) - then - return False; - end if; - - -- Comparison value was within range, so now we must check the index - -- value to make sure it is also within 32-bits. - - Indx := First_Index (Etype (Ent)); - - if Present (Index) then - for J in 2 .. UI_To_Int (Intval (Index)) loop - Next_Index (Indx); - end loop; - end if; - - Ityp := Etype (Indx); - - if Esize (Ityp) > 32 then - return False; - end if; - - Is_Zero := False; - Comp := N; - return True; - end Is_Optimizable; - - ---------------- - -- Prepare_64 -- - ---------------- - - function Prepare_64 (N : Node_Id) return Node_Id is - begin - return Unchecked_Convert_To (Standard_Long_Long_Integer, N); - end Prepare_64; - - -- Start of processing for Optimize_Length_Comparison - - begin - -- Nothing to do if not a comparison - - if Op not in N_Op_Compare then - return; - end if; - - -- Nothing to do if special -gnatd.P debug flag set - - if Debug_Flag_Dot_PP then - return; - end if; - - -- Ent'Length op 0/1 - - if Is_Entity_Length (Left_Opnd (N)) - and then Is_Optimizable (Right_Opnd (N)) - then - null; - - -- 0/1 op Ent'Length - - elsif Is_Entity_Length (Right_Opnd (N)) - and then Is_Optimizable (Left_Opnd (N)) - then - -- Flip comparison to opposite sense - - case Op is - when N_Op_Lt => Op := N_Op_Gt; - when N_Op_Le => Op := N_Op_Ge; - when N_Op_Gt => Op := N_Op_Lt; - when N_Op_Ge => Op := N_Op_Le; - when others => null; - end case; - - -- Else optimization not possible - - else - return; - end if; - - -- Fall through if we will do the optimization - - -- Cases to handle: - - -- X'Length = 0 => X'First > X'Last - -- X'Length = 1 => X'First = X'Last - -- X'Length = n => X'First + (n - 1) = X'Last - - -- X'Length /= 0 => X'First <= X'Last - -- X'Length /= 1 => X'First /= X'Last - -- X'Length /= n => X'First + (n - 1) /= X'Last - - -- X'Length >= 0 => always true, warn - -- X'Length >= 1 => X'First <= X'Last - -- X'Length >= n => X'First + (n - 1) <= X'Last - - -- X'Length > 0 => X'First <= X'Last - -- X'Length > 1 => X'First < X'Last - -- X'Length > n => X'First + (n - 1) < X'Last - - -- X'Length <= 0 => X'First > X'Last (warn, could be =) - -- X'Length <= 1 => X'First >= X'Last - -- X'Length <= n => X'First + (n - 1) >= X'Last - - -- X'Length < 0 => always false (warn) - -- X'Length < 1 => X'First > X'Last - -- X'Length < n => X'First + (n - 1) > X'Last - - -- Note: for the cases of n (not constant 0,1), we require that the - -- corresponding index type be integer or shorter (i.e. not 64-bit), - -- and the same for the comparison value. Then we do the comparison - -- using 64-bit arithmetic (actually long long integer), so that we - -- cannot have overflow intefering with the result. - - -- First deal with warning cases - - if Is_Zero then - case Op is - - -- X'Length >= 0 - - when N_Op_Ge => - Rewrite (N, - Convert_To (Typ, New_Occurrence_Of (Standard_True, Loc))); - Analyze_And_Resolve (N, Typ); - Warn_On_Known_Condition (N); - return; - - -- X'Length < 0 - - when N_Op_Lt => - Rewrite (N, - Convert_To (Typ, New_Occurrence_Of (Standard_False, Loc))); - Analyze_And_Resolve (N, Typ); - Warn_On_Known_Condition (N); - return; - - when N_Op_Le => - if Constant_Condition_Warnings - and then Comes_From_Source (Original_Node (N)) - then - Error_Msg_N ("could replace by ""'=""?c?", N); - end if; - - Op := N_Op_Eq; - - when others => - null; - end case; - end if; - - -- Build the First reference we will use - - Left := - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Ent, Loc), - Attribute_Name => Name_First); - - if Present (Index) then - Set_Expressions (Left, New_List (New_Copy (Index))); - end if; - - -- If general value case, then do the addition of (n - 1), and - -- also add the needed conversions to type Long_Long_Integer. - - if Present (Comp) then - Left := - Make_Op_Add (Loc, - Left_Opnd => Prepare_64 (Left), - Right_Opnd => - Make_Op_Subtract (Loc, - Left_Opnd => Prepare_64 (Comp), - Right_Opnd => Make_Integer_Literal (Loc, 1))); - end if; - - -- Build the Last reference we will use - - Right := - Make_Attribute_Reference (Loc, - Prefix => New_Occurrence_Of (Ent, Loc), - Attribute_Name => Name_Last); - - if Present (Index) then - Set_Expressions (Right, New_List (New_Copy (Index))); - end if; - - -- If general operand, convert Last reference to Long_Long_Integer - - if Present (Comp) then - Right := Prepare_64 (Right); - end if; - - -- Check for cases to optimize - - -- X'Length = 0 => X'First > X'Last - -- X'Length < 1 => X'First > X'Last - -- X'Length < n => X'First + (n - 1) > X'Last - - if (Is_Zero and then Op = N_Op_Eq) - or else (not Is_Zero and then Op = N_Op_Lt) - then - Result := - Make_Op_Gt (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length = 1 => X'First = X'Last - -- X'Length = n => X'First + (n - 1) = X'Last - - elsif not Is_Zero and then Op = N_Op_Eq then - Result := - Make_Op_Eq (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length /= 0 => X'First <= X'Last - -- X'Length > 0 => X'First <= X'Last - - elsif Is_Zero and (Op = N_Op_Ne or else Op = N_Op_Gt) then - Result := - Make_Op_Le (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length /= 1 => X'First /= X'Last - -- X'Length /= n => X'First + (n - 1) /= X'Last - - elsif not Is_Zero and then Op = N_Op_Ne then - Result := - Make_Op_Ne (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length >= 1 => X'First <= X'Last - -- X'Length >= n => X'First + (n - 1) <= X'Last - - elsif not Is_Zero and then Op = N_Op_Ge then - Result := - Make_Op_Le (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length > 1 => X'First < X'Last - -- X'Length > n => X'First + (n = 1) < X'Last - - elsif not Is_Zero and then Op = N_Op_Gt then - Result := - Make_Op_Lt (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- X'Length <= 1 => X'First >= X'Last - -- X'Length <= n => X'First + (n - 1) >= X'Last - - elsif not Is_Zero and then Op = N_Op_Le then - Result := - Make_Op_Ge (Loc, - Left_Opnd => Left, - Right_Opnd => Right); - - -- Should not happen at this stage - - else - raise Program_Error; - end if; - - -- Rewrite and finish up - - Rewrite (N, Result); - Analyze_And_Resolve (N, Typ); - return; - end Optimize_Length_Comparison; - - ------------------------ - -- Rewrite_Comparison -- - ------------------------ - - procedure Rewrite_Comparison (N : Node_Id) is - Warning_Generated : Boolean := False; - -- Set to True if first pass with Assume_Valid generates a warning in - -- which case we skip the second pass to avoid warning overloaded. - - Result : Node_Id; - -- Set to Standard_True or Standard_False - - begin - if Nkind (N) = N_Type_Conversion then - Rewrite_Comparison (Expression (N)); - return; - - elsif Nkind (N) not in N_Op_Compare then - return; - end if; - - -- Now start looking at the comparison in detail. We potentially go - -- through this loop twice. The first time, Assume_Valid is set False - -- in the call to Compile_Time_Compare. If this call results in a - -- clear result of always True or Always False, that's decisive and - -- we are done. Otherwise we repeat the processing with Assume_Valid - -- set to True to generate additional warnings. We can skip that step - -- if Constant_Condition_Warnings is False. - - for AV in False .. True loop - declare - Typ : constant Entity_Id := Etype (N); - Op1 : constant Node_Id := Left_Opnd (N); - Op2 : constant Node_Id := Right_Opnd (N); - - Res : constant Compare_Result := - Compile_Time_Compare (Op1, Op2, Assume_Valid => AV); - -- Res indicates if compare outcome can be compile time determined - - True_Result : Boolean; - False_Result : Boolean; - - begin - case N_Op_Compare (Nkind (N)) is - when N_Op_Eq => - True_Result := Res = EQ; - False_Result := Res = LT or else Res = GT or else Res = NE; - - when N_Op_Ge => - True_Result := Res in Compare_GE; - False_Result := Res = LT; - - if Res = LE - and then Constant_Condition_Warnings - and then Comes_From_Source (Original_Node (N)) - and then Nkind (Original_Node (N)) = N_Op_Ge - and then not In_Instance - and then Is_Integer_Type (Etype (Left_Opnd (N))) - and then not Has_Warnings_Off (Etype (Left_Opnd (N))) - then - Error_Msg_N - ("can never be greater than, could replace by ""'=""?c?", - N); - Warning_Generated := True; - end if; - - when N_Op_Gt => - True_Result := Res = GT; - False_Result := Res in Compare_LE; - - when N_Op_Lt => - True_Result := Res = LT; - False_Result := Res in Compare_GE; - - when N_Op_Le => - True_Result := Res in Compare_LE; - False_Result := Res = GT; - - if Res = GE - and then Constant_Condition_Warnings - and then Comes_From_Source (Original_Node (N)) - and then Nkind (Original_Node (N)) = N_Op_Le - and then not In_Instance - and then Is_Integer_Type (Etype (Left_Opnd (N))) - and then not Has_Warnings_Off (Etype (Left_Opnd (N))) - then - Error_Msg_N - ("can never be less than, could replace by ""'=""?c?", N); - Warning_Generated := True; - end if; - - when N_Op_Ne => - True_Result := Res = NE or else Res = GT or else Res = LT; - False_Result := Res = EQ; - end case; - - -- If this is the first iteration, then we actually convert the - -- comparison into True or False, if the result is certain. - - if AV = False then - if True_Result or False_Result then - Result := Boolean_Literals (True_Result); - Rewrite (N, - Convert_To (Typ, - New_Occurrence_Of (Result, Sloc (N)))); - Analyze_And_Resolve (N, Typ); - Warn_On_Known_Condition (N); - return; - end if; - - -- If this is the second iteration (AV = True), and the original - -- node comes from source and we are not in an instance, then give - -- a warning if we know result would be True or False. Note: we - -- know Constant_Condition_Warnings is set if we get here. - - elsif Comes_From_Source (Original_Node (N)) - and then not In_Instance - then - if True_Result then - Error_Msg_N - ("condition can only be False if invalid values present??", - N); - elsif False_Result then - Error_Msg_N - ("condition can only be True if invalid values present??", - N); - end if; - end if; - end; - - -- Skip second iteration if not warning on constant conditions or - -- if the first iteration already generated a warning of some kind or - -- if we are in any case assuming all values are valid (so that the - -- first iteration took care of the valid case). - - exit when not Constant_Condition_Warnings; - exit when Warning_Generated; - exit when Assume_No_Invalid_Values; - end loop; - end Rewrite_Comparison; - - ---------------------------- - -- Safe_In_Place_Array_Op -- - ---------------------------- - - function Safe_In_Place_Array_Op - (Lhs : Node_Id; - Op1 : Node_Id; - Op2 : Node_Id) return Boolean - is - Target : Entity_Id; - - function Is_Safe_Operand (Op : Node_Id) return Boolean; - -- Operand is safe if it cannot overlap part of the target of the - -- operation. If the operand and the target are identical, the operand - -- is safe. The operand can be empty in the case of negation. - - function Is_Unaliased (N : Node_Id) return Boolean; - -- Check that N is a stand-alone entity - - ------------------ - -- Is_Unaliased -- - ------------------ - - function Is_Unaliased (N : Node_Id) return Boolean is - begin - return - Is_Entity_Name (N) - and then No (Address_Clause (Entity (N))) - and then No (Renamed_Object (Entity (N))); - end Is_Unaliased; - - --------------------- - -- Is_Safe_Operand -- - --------------------- - - function Is_Safe_Operand (Op : Node_Id) return Boolean is - begin - if No (Op) then - return True; - - elsif Is_Entity_Name (Op) then - return Is_Unaliased (Op); - - elsif Nkind_In (Op, N_Indexed_Component, N_Selected_Component) then - return Is_Unaliased (Prefix (Op)); - - elsif Nkind (Op) = N_Slice then - return - Is_Unaliased (Prefix (Op)) - and then Entity (Prefix (Op)) /= Target; - - elsif Nkind (Op) = N_Op_Not then - return Is_Safe_Operand (Right_Opnd (Op)); - - else - return False; - end if; - end Is_Safe_Operand; - - -- Start of processing for Safe_In_Place_Array_Op - - begin - -- Skip this processing if the component size is different from system - -- storage unit (since at least for NOT this would cause problems). - - if Component_Size (Etype (Lhs)) /= System_Storage_Unit then - return False; - - -- Cannot do in place stuff on VM_Target since cannot pass addresses - - elsif VM_Target /= No_VM then - return False; - - -- Cannot do in place stuff if non-standard Boolean representation - - elsif Has_Non_Standard_Rep (Component_Type (Etype (Lhs))) then - return False; - - elsif not Is_Unaliased (Lhs) then - return False; - - else - Target := Entity (Lhs); - return Is_Safe_Operand (Op1) and then Is_Safe_Operand (Op2); - end if; - end Safe_In_Place_Array_Op; - - ----------------------- - -- Tagged_Membership -- - ----------------------- - - -- There are two different cases to consider depending on whether the right - -- operand is a class-wide type or not. If not we just compare the actual - -- tag of the left expr to the target type tag: - -- - -- Left_Expr.Tag = Right_Type'Tag; - -- - -- If it is a class-wide type we use the RT function CW_Membership which is - -- usually implemented by looking in the ancestor tables contained in the - -- dispatch table pointed by Left_Expr.Tag for Typ'Tag - - -- Ada 2005 (AI-251): If it is a class-wide interface type we use the RT - -- function IW_Membership which is usually implemented by looking in the - -- table of abstract interface types plus the ancestor table contained in - -- the dispatch table pointed by Left_Expr.Tag for Typ'Tag - - procedure Tagged_Membership - (N : Node_Id; - SCIL_Node : out Node_Id; - Result : out Node_Id) - is - Left : constant Node_Id := Left_Opnd (N); - Right : constant Node_Id := Right_Opnd (N); - Loc : constant Source_Ptr := Sloc (N); - - Full_R_Typ : Entity_Id; - Left_Type : Entity_Id; - New_Node : Node_Id; - Right_Type : Entity_Id; - Obj_Tag : Node_Id; - - begin - SCIL_Node := Empty; - - -- Handle entities from the limited view - - Left_Type := Available_View (Etype (Left)); - Right_Type := Available_View (Etype (Right)); - - -- In the case where the type is an access type, the test is applied - -- using the designated types (needed in Ada 2012 for implicit anonymous - -- access conversions, for AI05-0149). - - if Is_Access_Type (Right_Type) then - Left_Type := Designated_Type (Left_Type); - Right_Type := Designated_Type (Right_Type); - end if; - - if Is_Class_Wide_Type (Left_Type) then - Left_Type := Root_Type (Left_Type); - end if; - - if Is_Class_Wide_Type (Right_Type) then - Full_R_Typ := Underlying_Type (Root_Type (Right_Type)); - else - Full_R_Typ := Underlying_Type (Right_Type); - end if; - - Obj_Tag := - Make_Selected_Component (Loc, - Prefix => Relocate_Node (Left), - Selector_Name => - New_Reference_To (First_Tag_Component (Left_Type), Loc)); - - if Is_Class_Wide_Type (Right_Type) then - - -- No need to issue a run-time check if we statically know that the - -- result of this membership test is always true. For example, - -- considering the following declarations: - - -- type Iface is interface; - -- type T is tagged null record; - -- type DT is new T and Iface with null record; - - -- Obj1 : T; - -- Obj2 : DT; - - -- These membership tests are always true: - - -- Obj1 in T'Class - -- Obj2 in T'Class; - -- Obj2 in Iface'Class; - - -- We do not need to handle cases where the membership is illegal. - -- For example: - - -- Obj1 in DT'Class; -- Compile time error - -- Obj1 in Iface'Class; -- Compile time error - - if not Is_Class_Wide_Type (Left_Type) - and then (Is_Ancestor (Etype (Right_Type), Left_Type, - Use_Full_View => True) - or else (Is_Interface (Etype (Right_Type)) - and then Interface_Present_In_Ancestor - (Typ => Left_Type, - Iface => Etype (Right_Type)))) - then - Result := New_Reference_To (Standard_True, Loc); - return; - end if; - - -- Ada 2005 (AI-251): Class-wide applied to interfaces - - if Is_Interface (Etype (Class_Wide_Type (Right_Type))) - - -- Support to: "Iface_CW_Typ in Typ'Class" - - or else Is_Interface (Left_Type) - then - -- Issue error if IW_Membership operation not available in a - -- configurable run time setting. - - if not RTE_Available (RE_IW_Membership) then - Error_Msg_CRT - ("dynamic membership test on interface types", N); - Result := Empty; - return; - end if; - - Result := - Make_Function_Call (Loc, - Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc), - Parameter_Associations => New_List ( - Make_Attribute_Reference (Loc, - Prefix => Obj_Tag, - Attribute_Name => Name_Address), - New_Reference_To ( - Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), - Loc))); - - -- Ada 95: Normal case - - else - Build_CW_Membership (Loc, - Obj_Tag_Node => Obj_Tag, - Typ_Tag_Node => - New_Reference_To ( - Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), Loc), - Related_Nod => N, - New_Node => New_Node); - - -- Generate the SCIL node for this class-wide membership test. - -- Done here because the previous call to Build_CW_Membership - -- relocates Obj_Tag. - - if Generate_SCIL then - SCIL_Node := Make_SCIL_Membership_Test (Sloc (N)); - Set_SCIL_Entity (SCIL_Node, Etype (Right_Type)); - Set_SCIL_Tag_Value (SCIL_Node, Obj_Tag); - end if; - - Result := New_Node; - end if; - - -- Right_Type is not a class-wide type - - else - -- No need to check the tag of the object if Right_Typ is abstract - - if Is_Abstract_Type (Right_Type) then - Result := New_Reference_To (Standard_False, Loc); - - else - Result := - Make_Op_Eq (Loc, - Left_Opnd => Obj_Tag, - Right_Opnd => - New_Reference_To - (Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), Loc)); - end if; - end if; - end Tagged_Membership; - - ------------------------------ - -- Unary_Op_Validity_Checks -- - ------------------------------ - - procedure Unary_Op_Validity_Checks (N : Node_Id) is - begin - if Validity_Checks_On and Validity_Check_Operands then - Ensure_Valid (Right_Opnd (N)); - end if; - end Unary_Op_Validity_Checks; - -end Exp_Ch4; |