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Diffstat (limited to 'gcc-4.4.0/gcc/ada/exp_intr.adb')
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diff --git a/gcc-4.4.0/gcc/ada/exp_intr.adb b/gcc-4.4.0/gcc/ada/exp_intr.adb new file mode 100644 index 000000000..d3f9334a6 --- /dev/null +++ b/gcc-4.4.0/gcc/ada/exp_intr.adb @@ -0,0 +1,1142 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ I N T R -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2008, 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 Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Exp_Atag; use Exp_Atag; +with Exp_Ch4; use Exp_Ch4; +with Exp_Ch7; use Exp_Ch7; +with Exp_Ch11; use Exp_Ch11; +with Exp_Code; use Exp_Code; +with Exp_Fixd; use Exp_Fixd; +with Exp_Util; use Exp_Util; +with Freeze; use Freeze; +with Namet; use Namet; +with Nmake; use Nmake; +with Nlists; use Nlists; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +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 Sinfo; use Sinfo; +with Sinput; use Sinput; +with Snames; use Snames; +with Stand; use Stand; +with Stringt; use Stringt; +with Targparm; use Targparm; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Urealp; use Urealp; + +package body Exp_Intr is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Expand_Is_Negative (N : Node_Id); + -- Expand a call to the intrinsic Is_Negative function + + procedure Expand_Dispatching_Constructor_Call (N : Node_Id); + -- Expand a call to an instantiation of Generic_Dispatching_Constructor + -- into a dispatching call to the actual subprogram associated with the + -- Constructor formal subprogram, passing it the Parameters actual of + -- the call to the instantiation and dispatching based on call's Tag + -- parameter. + + procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id); + -- Expand a call to Exception_Information/Message/Name. The first + -- parameter, N, is the node for the function call, and Ent is the + -- entity for the corresponding routine in the Ada.Exceptions package. + + procedure Expand_Import_Call (N : Node_Id); + -- Expand a call to Import_Address/Longest_Integer/Value. The parameter + -- N is the node for the function call. + + procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind); + -- Expand an intrinsic shift operation, N and E are from the call to + -- Expand_Intrinsic_Call (call node and subprogram spec entity) and + -- K is the kind for the shift node + + procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id); + -- Expand a call to an instantiation of Unchecked_Conversion into a node + -- N_Unchecked_Type_Conversion. + + procedure Expand_Unc_Deallocation (N : Node_Id); + -- Expand a call to an instantiation of Unchecked_Deallocation into a node + -- N_Free_Statement and appropriate context. + + procedure Expand_To_Address (N : Node_Id); + procedure Expand_To_Pointer (N : Node_Id); + -- Expand a call to corresponding function, declared in an instance of + -- System.Address_To_Access_Conversions. + + procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id); + -- Rewrite the node by the appropriate string or positive constant. + -- Nam can be one of the following: + -- Name_File - expand string that is the name of source file + -- Name_Line - expand integer line number + -- Name_Source_Location - expand string of form file:line + -- Name_Enclosing_Entity - expand string with name of enclosing entity + + ----------------------------------------- + -- Expand_Dispatching_Constructor_Call -- + ----------------------------------------- + + -- Transform a call to an instantiation of Generic_Dispatching_Constructor + -- of the form: + + -- GDC_Instance (The_Tag, Parameters'Access) + + -- to a class-wide conversion of a dispatching call to the actual + -- associated with the formal subprogram Construct, designating The_Tag + -- as the controlling tag of the call: + + -- T'Class (Construct'Actual (Params)) -- Controlling tag is The_Tag + + -- which will eventually be expanded to the following: + + -- T'Class (The_Tag.all (Construct'Actual'Index).all (Params)) + + -- A class-wide membership test is also generated, preceding the call, to + -- ensure that the controlling tag denotes a type in T'Class. + + procedure Expand_Dispatching_Constructor_Call (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Tag_Arg : constant Node_Id := First_Actual (N); + Param_Arg : constant Node_Id := Next_Actual (Tag_Arg); + Subp_Decl : constant Node_Id := Parent (Parent (Entity (Name (N)))); + Inst_Pkg : constant Node_Id := Parent (Subp_Decl); + Act_Rename : Node_Id; + Act_Constr : Entity_Id; + Iface_Tag : Node_Id := Empty; + Cnstr_Call : Node_Id; + Result_Typ : Entity_Id; + + begin + -- The subprogram is the third actual in the instantiation, and is + -- retrieved from the corresponding renaming declaration. However, + -- freeze nodes may appear before, so we retrieve the declaration + -- with an explicit loop. + + Act_Rename := First (Visible_Declarations (Inst_Pkg)); + while Nkind (Act_Rename) /= N_Subprogram_Renaming_Declaration loop + Next (Act_Rename); + end loop; + + Act_Constr := Entity (Name (Act_Rename)); + Result_Typ := Class_Wide_Type (Etype (Act_Constr)); + + -- Ada 2005 (AI-251): If the result is an interface type, the function + -- returns a class-wide interface type (otherwise the resulting object + -- would be abstract!) + + if Is_Interface (Etype (Act_Constr)) then + Set_Etype (Act_Constr, Result_Typ); + + -- If the result type is not parent of Tag_Arg then we need to + -- locate the tag of the secondary dispatch table. + + if not Is_Ancestor (Etype (Result_Typ), Etype (Tag_Arg)) then + pragma Assert (not Is_Interface (Etype (Tag_Arg))); + + Iface_Tag := + Make_Object_Declaration (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, New_Internal_Name ('V')), + Object_Definition => + New_Reference_To (RTE (RE_Tag), Loc), + Expression => + Make_Function_Call (Loc, + Name => New_Reference_To (RTE (RE_Secondary_Tag), Loc), + Parameter_Associations => New_List ( + Relocate_Node (Tag_Arg), + New_Reference_To + (Node (First_Elmt (Access_Disp_Table + (Etype (Etype (Act_Constr))))), + Loc)))); + Insert_Action (N, Iface_Tag); + end if; + end if; + + -- Create the call to the actual Constructor function + + Cnstr_Call := + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Act_Constr, Loc), + Parameter_Associations => New_List (Relocate_Node (Param_Arg))); + + -- Establish its controlling tag from the tag passed to the instance + -- The tag may be given by a function call, in which case a temporary + -- should be generated now, to prevent out-of-order insertions during + -- the expansion of that call when stack-checking is enabled. + + if Present (Iface_Tag) then + Set_Controlling_Argument (Cnstr_Call, + New_Occurrence_Of (Defining_Identifier (Iface_Tag), Loc)); + else + Remove_Side_Effects (Tag_Arg); + Set_Controlling_Argument (Cnstr_Call, + Relocate_Node (Tag_Arg)); + end if; + + -- Rewrite and analyze the call to the instance as a class-wide + -- conversion of the call to the actual constructor. + + Rewrite (N, Convert_To (Result_Typ, Cnstr_Call)); + Analyze_And_Resolve (N, Etype (Act_Constr)); + + -- Do not generate a run-time check on the built object if tag + -- checks are suppressed for the result type or VM_Target /= No_VM + + if Tag_Checks_Suppressed (Etype (Result_Typ)) + or else VM_Target /= No_VM + then + null; + + -- Generate a class-wide membership test to ensure that the call's tag + -- argument denotes a type within the class. We must keep separate the + -- case in which the Result_Type of the constructor function is a tagged + -- type from the case in which it is an abstract interface because the + -- run-time subprogram required to check these cases differ (and have + -- one difference in their parameters profile). + + -- Call CW_Membership if the Result_Type is a tagged type to look for + -- the tag in the table of ancestor tags. + + elsif not Is_Interface (Result_Typ) then + Insert_Action (N, + Make_Implicit_If_Statement (N, + Condition => + Make_Op_Not (Loc, + Build_CW_Membership (Loc, + Obj_Tag_Node => Duplicate_Subexpr (Tag_Arg), + Typ_Tag_Node => + New_Reference_To ( + Node (First_Elmt (Access_Disp_Table ( + Root_Type (Result_Typ)))), Loc))), + Then_Statements => + New_List (Make_Raise_Statement (Loc, + New_Occurrence_Of (RTE (RE_Tag_Error), Loc))))); + + -- Call IW_Membership test if the Result_Type is an abstract interface + -- to look for the tag in the table of interface tags. + + else + Insert_Action (N, + Make_Implicit_If_Statement (N, + Condition => + Make_Op_Not (Loc, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc), + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => Duplicate_Subexpr (Tag_Arg), + Attribute_Name => Name_Address), + + New_Reference_To ( + Node (First_Elmt (Access_Disp_Table ( + Root_Type (Result_Typ)))), Loc)))), + Then_Statements => + New_List ( + Make_Raise_Statement (Loc, + Name => New_Occurrence_Of (RTE (RE_Tag_Error), Loc))))); + end if; + end Expand_Dispatching_Constructor_Call; + + --------------------------- + -- Expand_Exception_Call -- + --------------------------- + + -- If the function call is not within an exception handler, then the call + -- is replaced by a null string. Otherwise the appropriate routine in + -- Ada.Exceptions is called passing the choice parameter specification + -- from the enclosing handler. If the enclosing handler lacks a choice + -- parameter, then one is supplied. + + procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id) is + Loc : constant Source_Ptr := Sloc (N); + P : Node_Id; + E : Entity_Id; + + begin + -- Climb up parents to see if we are in exception handler + + P := Parent (N); + loop + -- Case of not in exception handler, replace by null string + + if No (P) then + Rewrite (N, + Make_String_Literal (Loc, + Strval => "")); + exit; + + -- Case of in exception handler + + elsif Nkind (P) = N_Exception_Handler then + + -- Handler cannot be used for a local raise, and furthermore, this + -- is a violation of the No_Exception_Propagation restriction. + + Set_Local_Raise_Not_OK (P); + Check_Restriction (No_Exception_Propagation, N); + + -- If no choice parameter present, then put one there. Note that + -- we do not need to put it on the entity chain, since no one will + -- be referencing it by normal visibility methods. + + if No (Choice_Parameter (P)) then + E := Make_Defining_Identifier (Loc, New_Internal_Name ('E')); + Set_Choice_Parameter (P, E); + Set_Ekind (E, E_Variable); + Set_Etype (E, RTE (RE_Exception_Occurrence)); + Set_Scope (E, Current_Scope); + end if; + + Rewrite (N, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (Ent), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (Choice_Parameter (P), Loc)))); + exit; + + -- Keep climbing! + + else + P := Parent (P); + end if; + end loop; + + Analyze_And_Resolve (N, Standard_String); + end Expand_Exception_Call; + + ------------------------ + -- Expand_Import_Call -- + ------------------------ + + -- The function call must have a static string as its argument. We create + -- a dummy variable which uses this string as the external name in an + -- Import pragma. The result is then obtained as the address of this + -- dummy variable, converted to the appropriate target type. + + procedure Expand_Import_Call (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Ent : constant Entity_Id := Entity (Name (N)); + Str : constant Node_Id := First_Actual (N); + Dum : Entity_Id; + + begin + Dum := Make_Defining_Identifier (Loc, New_Internal_Name ('D')); + + Insert_Actions (N, New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Dum, + Object_Definition => + New_Occurrence_Of (Standard_Character, Loc)), + + Make_Pragma (Loc, + Chars => Name_Import, + Pragma_Argument_Associations => New_List ( + Make_Pragma_Argument_Association (Loc, + Expression => Make_Identifier (Loc, Name_Ada)), + + Make_Pragma_Argument_Association (Loc, + Expression => Make_Identifier (Loc, Chars (Dum))), + + Make_Pragma_Argument_Association (Loc, + Chars => Name_Link_Name, + Expression => Relocate_Node (Str)))))); + + Rewrite (N, + Unchecked_Convert_To (Etype (Ent), + Make_Attribute_Reference (Loc, + Prefix => Make_Identifier (Loc, Chars (Dum)), + Attribute_Name => Name_Address))); + + Analyze_And_Resolve (N, Etype (Ent)); + end Expand_Import_Call; + + --------------------------- + -- Expand_Intrinsic_Call -- + --------------------------- + + procedure Expand_Intrinsic_Call (N : Node_Id; E : Entity_Id) is + Nam : Name_Id; + + begin + -- If the intrinsic subprogram is generic, gets its original name + + if Present (Parent (E)) + and then Present (Generic_Parent (Parent (E))) + then + Nam := Chars (Generic_Parent (Parent (E))); + else + Nam := Chars (E); + end if; + + if Nam = Name_Asm then + Expand_Asm_Call (N); + + elsif Nam = Name_Divide then + Expand_Decimal_Divide_Call (N); + + elsif Nam = Name_Exception_Information then + Expand_Exception_Call (N, RE_Exception_Information); + + elsif Nam = Name_Exception_Message then + Expand_Exception_Call (N, RE_Exception_Message); + + elsif Nam = Name_Exception_Name then + Expand_Exception_Call (N, RE_Exception_Name_Simple); + + elsif Nam = Name_Generic_Dispatching_Constructor then + Expand_Dispatching_Constructor_Call (N); + + elsif Nam = Name_Import_Address + or else + Nam = Name_Import_Largest_Value + or else + Nam = Name_Import_Value + then + Expand_Import_Call (N); + + elsif Nam = Name_Is_Negative then + Expand_Is_Negative (N); + + elsif Nam = Name_Rotate_Left then + Expand_Shift (N, E, N_Op_Rotate_Left); + + elsif Nam = Name_Rotate_Right then + Expand_Shift (N, E, N_Op_Rotate_Right); + + elsif Nam = Name_Shift_Left then + Expand_Shift (N, E, N_Op_Shift_Left); + + elsif Nam = Name_Shift_Right then + Expand_Shift (N, E, N_Op_Shift_Right); + + elsif Nam = Name_Shift_Right_Arithmetic then + Expand_Shift (N, E, N_Op_Shift_Right_Arithmetic); + + elsif Nam = Name_Unchecked_Conversion then + Expand_Unc_Conversion (N, E); + + elsif Nam = Name_Unchecked_Deallocation then + Expand_Unc_Deallocation (N); + + elsif Nam = Name_To_Address then + Expand_To_Address (N); + + elsif Nam = Name_To_Pointer then + Expand_To_Pointer (N); + + elsif Nam = Name_File + or else Nam = Name_Line + or else Nam = Name_Source_Location + or else Nam = Name_Enclosing_Entity + then + Expand_Source_Info (N, Nam); + + -- If we have a renaming, expand the call to the original operation, + -- which must itself be intrinsic, since renaming requires matching + -- conventions and this has already been checked. + + elsif Present (Alias (E)) then + Expand_Intrinsic_Call (N, Alias (E)); + + -- The only other case is where an external name was specified, + -- since this is the only way that an otherwise unrecognized + -- name could escape the checking in Sem_Prag. Nothing needs + -- to be done in such a case, since we pass such a call to the + -- back end unchanged. + + else + null; + end if; + end Expand_Intrinsic_Call; + + ------------------------ + -- Expand_Is_Negative -- + ------------------------ + + procedure Expand_Is_Negative (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Opnd : constant Node_Id := Relocate_Node (First_Actual (N)); + + begin + + -- We replace the function call by the following expression + + -- if Opnd < 0.0 then + -- True + -- else + -- if Opnd > 0.0 then + -- False; + -- else + -- Float_Unsigned!(Float (Opnd)) /= 0 + -- end if; + -- end if; + + Rewrite (N, + Make_Conditional_Expression (Loc, + Expressions => New_List ( + Make_Op_Lt (Loc, + Left_Opnd => Duplicate_Subexpr (Opnd), + Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), + + New_Occurrence_Of (Standard_True, Loc), + + Make_Conditional_Expression (Loc, + Expressions => New_List ( + Make_Op_Gt (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Opnd), + Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), + + New_Occurrence_Of (Standard_False, Loc), + + Make_Op_Ne (Loc, + Left_Opnd => + Unchecked_Convert_To + (RTE (RE_Float_Unsigned), + Convert_To + (Standard_Float, + Duplicate_Subexpr_No_Checks (Opnd))), + Right_Opnd => + Make_Integer_Literal (Loc, 0))))))); + + Analyze_And_Resolve (N, Standard_Boolean); + end Expand_Is_Negative; + + ------------------ + -- Expand_Shift -- + ------------------ + + -- This procedure is used to convert a call to a shift function to the + -- corresponding operator node. This conversion is not done by the usual + -- circuit for converting calls to operator functions (e.g. "+"(1,2)) to + -- operator nodes, because shifts are not predefined operators. + + -- As a result, whenever a shift is used in the source program, it will + -- remain as a call until converted by this routine to the operator node + -- form which Gigi is expecting to see. + + -- Note: it is possible for the expander to generate shift operator nodes + -- directly, which will be analyzed in the normal manner by calling Analyze + -- and Resolve. Such shift operator nodes will not be seen by Expand_Shift. + + procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Left : constant Node_Id := First_Actual (N); + Right : constant Node_Id := Next_Actual (Left); + Ltyp : constant Node_Id := Etype (Left); + Rtyp : constant Node_Id := Etype (Right); + Snode : Node_Id; + + begin + Snode := New_Node (K, Loc); + Set_Left_Opnd (Snode, Relocate_Node (Left)); + Set_Right_Opnd (Snode, Relocate_Node (Right)); + Set_Chars (Snode, Chars (E)); + Set_Etype (Snode, Base_Type (Typ)); + Set_Entity (Snode, E); + + if Compile_Time_Known_Value (Type_High_Bound (Rtyp)) + and then Expr_Value (Type_High_Bound (Rtyp)) < Esize (Ltyp) + then + Set_Shift_Count_OK (Snode, True); + end if; + + -- Do the rewrite. Note that we don't call Analyze and Resolve on + -- this node, because it already got analyzed and resolved when + -- it was a function call! + + Rewrite (N, Snode); + Set_Analyzed (N); + end Expand_Shift; + + ------------------------ + -- Expand_Source_Info -- + ------------------------ + + procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id) is + Loc : constant Source_Ptr := Sloc (N); + Ent : Entity_Id; + + procedure Write_Entity_Name (E : Entity_Id); + -- Recursive procedure to construct string for qualified name of + -- enclosing program unit. The qualification stops at an enclosing + -- scope has no source name (block or loop). If entity is a subprogram + -- instance, skip enclosing wrapper package. + + ----------------------- + -- Write_Entity_Name -- + ----------------------- + + procedure Write_Entity_Name (E : Entity_Id) is + SDef : Source_Ptr; + TDef : constant Source_Buffer_Ptr := + Source_Text (Get_Source_File_Index (Sloc (E))); + + begin + -- Nothing to do if at outer level + + if Scope (E) = Standard_Standard then + null; + + -- If scope comes from source, write its name + + elsif Comes_From_Source (Scope (E)) then + Write_Entity_Name (Scope (E)); + Add_Char_To_Name_Buffer ('.'); + + -- If in wrapper package skip past it + + elsif Is_Wrapper_Package (Scope (E)) then + Write_Entity_Name (Scope (Scope (E))); + Add_Char_To_Name_Buffer ('.'); + + -- Otherwise nothing to output (happens in unnamed block statements) + + else + null; + end if; + + -- Loop to output the name + + -- is this right wrt wide char encodings ??? (no!) + + SDef := Sloc (E); + while TDef (SDef) in '0' .. '9' + or else TDef (SDef) >= 'A' + or else TDef (SDef) = ASCII.ESC + loop + Add_Char_To_Name_Buffer (TDef (SDef)); + SDef := SDef + 1; + end loop; + end Write_Entity_Name; + + -- Start of processing for Expand_Source_Info + + begin + -- Integer cases + + if Nam = Name_Line then + Rewrite (N, + Make_Integer_Literal (Loc, + Intval => UI_From_Int (Int (Get_Logical_Line_Number (Loc))))); + Analyze_And_Resolve (N, Standard_Positive); + + -- String cases + + else + Name_Len := 0; + + case Nam is + when Name_File => + Get_Decoded_Name_String + (Reference_Name (Get_Source_File_Index (Loc))); + + when Name_Source_Location => + Build_Location_String (Loc); + + when Name_Enclosing_Entity => + + -- Skip enclosing blocks to reach enclosing unit + + Ent := Current_Scope; + while Present (Ent) loop + exit when Ekind (Ent) /= E_Block + and then Ekind (Ent) /= E_Loop; + Ent := Scope (Ent); + end loop; + + -- Ent now points to the relevant defining entity + + Write_Entity_Name (Ent); + + when others => + raise Program_Error; + end case; + + Rewrite (N, + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer)); + Analyze_And_Resolve (N, Standard_String); + end if; + + Set_Is_Static_Expression (N); + end Expand_Source_Info; + + --------------------------- + -- Expand_Unc_Conversion -- + --------------------------- + + procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id) is + Func : constant Entity_Id := Entity (Name (N)); + Conv : Node_Id; + Ftyp : Entity_Id; + Ttyp : Entity_Id; + + begin + -- Rewrite as unchecked conversion node. Note that we must convert + -- the operand to the formal type of the input parameter of the + -- function, so that the resulting N_Unchecked_Type_Conversion + -- call indicates the correct types for Gigi. + + -- Right now, we only do this if a scalar type is involved. It is + -- not clear if it is needed in other cases. If we do attempt to + -- do the conversion unconditionally, it crashes 3411-018. To be + -- investigated further ??? + + Conv := Relocate_Node (First_Actual (N)); + Ftyp := Etype (First_Formal (Func)); + + if Is_Scalar_Type (Ftyp) then + Conv := Convert_To (Ftyp, Conv); + Set_Parent (Conv, N); + Analyze_And_Resolve (Conv); + end if; + + -- The instantiation of Unchecked_Conversion creates a wrapper package, + -- and the target type is declared as a subtype of the actual. Recover + -- the actual, which is the subtype indic. in the subtype declaration + -- for the target type. This is semantically correct, and avoids + -- anomalies with access subtypes. For entities, leave type as is. + + -- We do the analysis here, because we do not want the compiler + -- to try to optimize or otherwise reorganize the unchecked + -- conversion node. + + Ttyp := Etype (E); + + if Is_Entity_Name (Conv) then + null; + + elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then + Ttyp := Entity (Subtype_Indication (Parent (Etype (E)))); + + elsif Is_Itype (Ttyp) then + Ttyp := + Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp))); + else + raise Program_Error; + end if; + + Rewrite (N, Unchecked_Convert_To (Ttyp, Conv)); + Set_Etype (N, Ttyp); + Set_Analyzed (N); + + if Nkind (N) = N_Unchecked_Type_Conversion then + Expand_N_Unchecked_Type_Conversion (N); + end if; + end Expand_Unc_Conversion; + + ----------------------------- + -- Expand_Unc_Deallocation -- + ----------------------------- + + -- Generate the following Code : + + -- if Arg /= null then + -- <Finalize_Call> (.., T'Class(Arg.all), ..); -- for controlled types + -- Free (Arg); + -- Arg := Null; + -- end if; + + -- For a task, we also generate a call to Free_Task to ensure that the + -- task itself is freed if it is terminated, ditto for a simple protected + -- object, with a call to Finalize_Protection. For composite types that + -- have tasks or simple protected objects as components, we traverse the + -- structures to find and terminate those components. + + procedure Expand_Unc_Deallocation (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Arg : constant Node_Id := First_Actual (N); + Typ : constant Entity_Id := Etype (Arg); + Stmts : constant List_Id := New_List; + Rtyp : constant Entity_Id := Underlying_Type (Root_Type (Typ)); + Pool : constant Entity_Id := Associated_Storage_Pool (Rtyp); + + Desig_T : constant Entity_Id := Designated_Type (Typ); + Gen_Code : Node_Id; + Free_Node : Node_Id; + Deref : Node_Id; + Free_Arg : Node_Id; + Free_Cod : List_Id; + Blk : Node_Id; + + Arg_Known_Non_Null : constant Boolean := Known_Non_Null (N); + -- This captures whether we know the argument to be non-null so that + -- we can avoid the test. The reason that we need to capture this is + -- that we analyze some generated statements before properly attaching + -- them to the tree, and that can disturb current value settings. + + begin + if No_Pool_Assigned (Rtyp) then + Error_Msg_N ("?deallocation from empty storage pool!", N); + end if; + + -- Nothing to do if we know the argument is null + + if Known_Null (N) then + return; + end if; + + -- Processing for pointer to controlled type + + if Needs_Finalization (Desig_T) then + Deref := + Make_Explicit_Dereference (Loc, + Prefix => Duplicate_Subexpr_No_Checks (Arg)); + + -- If the type is tagged, then we must force dispatching on the + -- finalization call because the designated type may not be the + -- actual type of the object. + + if Is_Tagged_Type (Desig_T) + and then not Is_Class_Wide_Type (Desig_T) + then + Deref := Unchecked_Convert_To (Class_Wide_Type (Desig_T), Deref); + + elsif not Is_Tagged_Type (Desig_T) then + + -- Set type of result, to force a conversion when needed (see + -- exp_ch7, Convert_View), given that Deep_Finalize may be + -- inherited from the parent type, and we need the type of the + -- expression to see whether the conversion is in fact needed. + + Set_Etype (Deref, Desig_T); + end if; + + Free_Cod := + Make_Final_Call + (Ref => Deref, + Typ => Desig_T, + With_Detach => New_Reference_To (Standard_True, Loc)); + + if Abort_Allowed then + Prepend_To (Free_Cod, + Build_Runtime_Call (Loc, RE_Abort_Defer)); + + Blk := + Make_Block_Statement (Loc, Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Free_Cod, + At_End_Proc => + New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc))); + + -- We now expand the exception (at end) handler. We set a + -- temporary parent pointer since we have not attached Blk + -- to the tree yet. + + Set_Parent (Blk, N); + Analyze (Blk); + Expand_At_End_Handler + (Handled_Statement_Sequence (Blk), Entity (Identifier (Blk))); + Append (Blk, Stmts); + + -- We kill saved current values, since analyzing statements not + -- properly attached to the tree can set wrong current values. + + Kill_Current_Values; + + else + Append_List_To (Stmts, Free_Cod); + end if; + end if; + + -- For a task type, call Free_Task before freeing the ATCB + + if Is_Task_Type (Desig_T) then + declare + Stat : Node_Id := Prev (N); + Nam1 : Node_Id; + Nam2 : Node_Id; + + begin + -- An Abort followed by a Free will not do what the user + -- expects, because the abort is not immediate. This is + -- worth a friendly warning. + + while Present (Stat) + and then not Comes_From_Source (Original_Node (Stat)) + loop + Prev (Stat); + end loop; + + if Present (Stat) + and then Nkind (Original_Node (Stat)) = N_Abort_Statement + then + Stat := Original_Node (Stat); + Nam1 := First (Names (Stat)); + Nam2 := Original_Node (First (Parameter_Associations (N))); + + if Nkind (Nam1) = N_Explicit_Dereference + and then Is_Entity_Name (Prefix (Nam1)) + and then Is_Entity_Name (Nam2) + and then Entity (Prefix (Nam1)) = Entity (Nam2) + then + Error_Msg_N ("abort may take time to complete?", N); + Error_Msg_N ("\deallocation might have no effect?", N); + Error_Msg_N ("\safer to wait for termination.?", N); + end if; + end if; + end; + + Append_To + (Stmts, Cleanup_Task (N, Duplicate_Subexpr_No_Checks (Arg))); + + -- For composite types that contain tasks, recurse over the structure + -- to build the selectors for the task subcomponents. + + elsif Has_Task (Desig_T) then + if Is_Record_Type (Desig_T) then + Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T)); + + elsif Is_Array_Type (Desig_T) then + Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T)); + end if; + end if; + + -- Same for simple protected types. Eventually call Finalize_Protection + -- before freeing the PO for each protected component. + + if Is_Simple_Protected_Type (Desig_T) then + Append_To (Stmts, + Cleanup_Protected_Object (N, Duplicate_Subexpr_No_Checks (Arg))); + + elsif Has_Simple_Protected_Object (Desig_T) then + if Is_Record_Type (Desig_T) then + Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T)); + elsif Is_Array_Type (Desig_T) then + Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T)); + end if; + end if; + + -- Normal processing for non-controlled types + + Free_Arg := Duplicate_Subexpr_No_Checks (Arg); + Free_Node := Make_Free_Statement (Loc, Empty); + Append_To (Stmts, Free_Node); + Set_Storage_Pool (Free_Node, Pool); + + -- Deal with storage pool + + if Present (Pool) then + + -- Freeing the secondary stack is meaningless + + if Is_RTE (Pool, RE_SS_Pool) then + null; + + elsif Is_Class_Wide_Type (Etype (Pool)) then + + -- Case of a class-wide pool type: make a dispatching call + -- to Deallocate through the class-wide Deallocate_Any. + + Set_Procedure_To_Call (Free_Node, + RTE (RE_Deallocate_Any)); + + else + -- Case of a specific pool type: make a statically bound call + + Set_Procedure_To_Call (Free_Node, + Find_Prim_Op (Etype (Pool), Name_Deallocate)); + end if; + end if; + + if Present (Procedure_To_Call (Free_Node)) then + + -- For all cases of a Deallocate call, the back-end needs to be + -- able to compute the size of the object being freed. This may + -- require some adjustments for objects of dynamic size. + -- + -- If the type is class wide, we generate an implicit type with the + -- right dynamic size, so that the deallocate call gets the right + -- size parameter computed by GIGI. Same for an access to + -- unconstrained packed array. + + if Is_Class_Wide_Type (Desig_T) + or else + (Is_Array_Type (Desig_T) + and then not Is_Constrained (Desig_T) + and then Is_Packed (Desig_T)) + then + declare + Deref : constant Node_Id := + Make_Explicit_Dereference (Loc, + Duplicate_Subexpr_No_Checks (Arg)); + D_Subtyp : Node_Id; + D_Type : Entity_Id; + + begin + Set_Etype (Deref, Typ); + Set_Parent (Deref, Free_Node); + D_Subtyp := Make_Subtype_From_Expr (Deref, Desig_T); + + if Nkind (D_Subtyp) in N_Has_Entity then + D_Type := Entity (D_Subtyp); + + else + D_Type := Make_Defining_Identifier (Loc, + New_Internal_Name ('A')); + Insert_Action (N, + Make_Subtype_Declaration (Loc, + Defining_Identifier => D_Type, + Subtype_Indication => D_Subtyp)); + Freeze_Itype (D_Type, N); + + end if; + + Set_Actual_Designated_Subtype (Free_Node, D_Type); + end; + + end if; + end if; + + -- Ada 2005 (AI-251): In case of abstract interface type we must + -- displace the pointer to reference the base of the object to + -- deallocate its memory, unless we're targetting a VM, in which case + -- no special processing is required. + + -- Generate: + -- free (Base_Address (Obj_Ptr)) + + if Is_Interface (Directly_Designated_Type (Typ)) + and then VM_Target = No_VM + then + Set_Expression (Free_Node, + Unchecked_Convert_To (Typ, + Make_Function_Call (Loc, + Name => New_Reference_To (RTE (RE_Base_Address), Loc), + Parameter_Associations => New_List ( + Unchecked_Convert_To (RTE (RE_Address), Free_Arg))))); + + -- Generate: + -- free (Obj_Ptr) + + else + Set_Expression (Free_Node, Free_Arg); + end if; + + -- Only remaining step is to set result to null, or generate a + -- raise of constraint error if the target object is "not null". + + if Can_Never_Be_Null (Etype (Arg)) then + Append_To (Stmts, + Make_Raise_Constraint_Error (Loc, + Reason => CE_Access_Check_Failed)); + + else + declare + Lhs : constant Node_Id := Duplicate_Subexpr_No_Checks (Arg); + begin + Set_Assignment_OK (Lhs); + Append_To (Stmts, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Make_Null (Loc))); + end; + end if; + + -- If we know the argument is non-null, then make a block statement + -- that contains the required statements, no need for a test. + + if Arg_Known_Non_Null then + Gen_Code := + Make_Block_Statement (Loc, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Stmts)); + + -- If the argument may be null, wrap the statements inside an IF that + -- does an explicit test to exclude the null case. + + else + Gen_Code := + Make_Implicit_If_Statement (N, + Condition => + Make_Op_Ne (Loc, + Left_Opnd => Duplicate_Subexpr (Arg), + Right_Opnd => Make_Null (Loc)), + Then_Statements => Stmts); + end if; + + -- Rewrite the call + + Rewrite (N, Gen_Code); + Analyze (N); + end Expand_Unc_Deallocation; + + ----------------------- + -- Expand_To_Address -- + ----------------------- + + procedure Expand_To_Address (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Arg : constant Node_Id := First_Actual (N); + Obj : Node_Id; + + begin + Remove_Side_Effects (Arg); + + Obj := Make_Explicit_Dereference (Loc, Relocate_Node (Arg)); + + Rewrite (N, + Make_Conditional_Expression (Loc, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => New_Copy_Tree (Arg), + Right_Opnd => Make_Null (Loc)), + New_Occurrence_Of (RTE (RE_Null_Address), Loc), + Make_Attribute_Reference (Loc, + Prefix => Obj, + Attribute_Name => Name_Address)))); + + Analyze_And_Resolve (N, RTE (RE_Address)); + end Expand_To_Address; + + ----------------------- + -- Expand_To_Pointer -- + ----------------------- + + procedure Expand_To_Pointer (N : Node_Id) is + Arg : constant Node_Id := First_Actual (N); + + begin + Rewrite (N, Unchecked_Convert_To (Etype (N), Arg)); + Analyze (N); + end Expand_To_Pointer; + +end Exp_Intr; |