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Diffstat (limited to 'gcc-4.3.1/gcc/ada/exp_ch6.adb')
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diff --git a/gcc-4.3.1/gcc/ada/exp_ch6.adb b/gcc-4.3.1/gcc/ada/exp_ch6.adb new file mode 100644 index 000000000..e8f5c114a --- /dev/null +++ b/gcc-4.3.1/gcc/ada/exp_ch6.adb @@ -0,0 +1,5567 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ C H 6 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2007, 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 Errout; use Errout; +with Elists; use Elists; +with Exp_Atag; use Exp_Atag; +with Exp_Ch2; use Exp_Ch2; +with Exp_Ch3; use Exp_Ch3; +with Exp_Ch7; use Exp_Ch7; +with Exp_Ch9; use Exp_Ch9; +with Exp_Dbug; use Exp_Dbug; +with Exp_Disp; use Exp_Disp; +with Exp_Dist; use Exp_Dist; +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 Fname; use Fname; +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 Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch8; use Sem_Ch8; +with Sem_Ch12; use Sem_Ch12; +with Sem_Ch13; use Sem_Ch13; +with Sem_Eval; use Sem_Eval; +with Sem_Disp; use Sem_Disp; +with Sem_Dist; use Sem_Dist; +with Sem_Mech; use Sem_Mech; +with Sem_Res; use Sem_Res; +with Sem_Util; use Sem_Util; +with Sinfo; use Sinfo; +with Snames; use Snames; +with Stand; use Stand; +with Targparm; use Targparm; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Validsw; use Validsw; + +package body Exp_Ch6 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Add_Access_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Return_Object : Node_Id; + Is_Access : Boolean := False); + -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the + -- object name given by Return_Object and add the attribute to the end of + -- the actual parameter list associated with the build-in-place function + -- call denoted by Function_Call. However, if Is_Access is True, then + -- Return_Object is already an access expression, in which case it's passed + -- along directly to the build-in-place function. Finally, if Return_Object + -- is empty, then pass a null literal as the actual. + + procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Alloc_Form : BIP_Allocation_Form := Unspecified; + Alloc_Form_Exp : Node_Id := Empty); + -- Ada 2005 (AI-318-02): Add an actual indicating the form of allocation, + -- if any, to be done by a build-in-place function. If Alloc_Form_Exp is + -- present, then use it, otherwise pass a literal corresponding to the + -- Alloc_Form parameter (which must not be Unspecified in that case). + + procedure Add_Extra_Actual_To_Call + (Subprogram_Call : Node_Id; + Extra_Formal : Entity_Id; + Extra_Actual : Node_Id); + -- Adds Extra_Actual as a named parameter association for the formal + -- Extra_Formal in Subprogram_Call. + + procedure Add_Final_List_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Acc_Type : Entity_Id); + -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type has + -- controlled parts, add an actual parameter that is a pointer to + -- appropriate finalization list. The finalization list is that of the + -- current scope, except for "new Acc'(F(...))" in which case it's the + -- finalization list of the access type returned by the allocator. Acc_Type + -- is that type in the allocator case; Empty otherwise. + + procedure Add_Task_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Master_Actual : Node_Id); + -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type + -- contains tasks, add two actual parameters: the master, and a pointer to + -- the caller's activation chain. Master_Actual is the actual parameter + -- expression to pass for the master. In most cases, this is the current + -- master (_master). The two exceptions are: If the function call is the + -- initialization expression for an allocator, we pass the master of the + -- access type. If the function call is the initialization expression for + -- a return object, we pass along the master passed in by the caller. The + -- activation chain to pass is always the local one. + + procedure Check_Overriding_Operation (Subp : Entity_Id); + -- Subp is a dispatching operation. Check whether it may override an + -- inherited private operation, in which case its DT entry is that of + -- the hidden operation, not the one it may have received earlier. + -- This must be done before emitting the code to set the corresponding + -- DT to the address of the subprogram. The actual placement of Subp in + -- the proper place in the list of primitive operations is done in + -- Declare_Inherited_Private_Subprograms, which also has to deal with + -- implicit operations. This duplication is unavoidable for now??? + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id); + -- This procedure is called only if the subprogram body N, whose spec + -- has the given entity Spec, contains a parameterless recursive call. + -- It attempts to generate runtime code to detect if this a case of + -- infinite recursion. + -- + -- The body is scanned to determine dependencies. If the only external + -- dependencies are on a small set of scalar variables, then the values + -- of these variables are captured on entry to the subprogram, and if + -- the values are not changed for the call, we know immediately that + -- we have an infinite recursion. + + procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id); + -- For each actual of an in-out or out parameter which is a numeric + -- (view) conversion of the form T (A), where A denotes a variable, + -- we insert the declaration: + -- + -- Temp : T[ := T (A)]; + -- + -- prior to the call. Then we replace the actual with a reference to Temp, + -- and append the assignment: + -- + -- A := TypeA (Temp); + -- + -- after the call. Here TypeA is the actual type of variable A. + -- For out parameters, the initial declaration has no expression. + -- If A is not an entity name, we generate instead: + -- + -- Var : TypeA renames A; + -- Temp : T := Var; -- omitting expression for out parameter. + -- ... + -- Var := TypeA (Temp); + -- + -- For other in-out parameters, we emit the required constraint checks + -- before and/or after the call. + -- + -- For all parameter modes, actuals that denote components and slices + -- of packed arrays are expanded into suitable temporaries. + -- + -- For non-scalar objects that are possibly unaligned, add call by copy + -- code (copy in for IN and IN OUT, copy out for OUT and IN OUT). + + procedure Expand_Inlined_Call + (N : Node_Id; + Subp : Entity_Id; + Orig_Subp : Entity_Id); + -- If called subprogram can be inlined by the front-end, retrieve the + -- analyzed body, replace formals with actuals and expand call in place. + -- Generate thunks for actuals that are expressions, and insert the + -- corresponding constant declarations before the call. If the original + -- call is to a derived operation, the return type is the one of the + -- derived operation, but the body is that of the original, so return + -- expressions in the body must be converted to the desired type (which + -- is simply not noted in the tree without inline expansion). + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) return Node_Id; + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id); + -- A call to a protected subprogram within the protected object may appear + -- as a regular call. The list of actuals must be expanded to contain a + -- reference to the object itself, and the call becomes a call to the + -- corresponding protected subprogram. + + ---------------------------------------------- + -- Add_Access_Actual_To_Build_In_Place_Call -- + ---------------------------------------------- + + procedure Add_Access_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Return_Object : Node_Id; + Is_Access : Boolean := False) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Obj_Address : Node_Id; + Obj_Acc_Formal : Entity_Id; + + begin + -- Locate the implicit access parameter in the called function + + Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access); + + -- If no return object is provided, then pass null + + if not Present (Return_Object) then + Obj_Address := Make_Null (Loc); + Set_Parent (Obj_Address, Function_Call); + + -- If Return_Object is already an expression of an access type, then use + -- it directly, since it must be an access value denoting the return + -- object, and couldn't possibly be the return object itself. + + elsif Is_Access then + Obj_Address := Return_Object; + Set_Parent (Obj_Address, Function_Call); + + -- Apply Unrestricted_Access to caller's return object + + else + Obj_Address := + Make_Attribute_Reference (Loc, + Prefix => Return_Object, + Attribute_Name => Name_Unrestricted_Access); + + Set_Parent (Return_Object, Obj_Address); + Set_Parent (Obj_Address, Function_Call); + end if; + + Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address); + end Add_Access_Actual_To_Build_In_Place_Call; + + -------------------------------------------------- + -- Add_Alloc_Form_Actual_To_Build_In_Place_Call -- + -------------------------------------------------- + + procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Alloc_Form : BIP_Allocation_Form := Unspecified; + Alloc_Form_Exp : Node_Id := Empty) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Alloc_Form_Actual : Node_Id; + Alloc_Form_Formal : Node_Id; + + begin + -- The allocation form generally doesn't need to be passed in the case + -- of a constrained result subtype, since normally the caller performs + -- the allocation in that case. However this formal is still needed in + -- the case where the function has a tagged result, because generally + -- such functions can be called in a dispatching context and such calls + -- must be handled like calls to class-wide functions. + + if Is_Constrained (Underlying_Type (Etype (Function_Id))) + and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id))) + then + return; + end if; + + -- Locate the implicit allocation form parameter in the called function. + -- Maybe it would be better for each implicit formal of a build-in-place + -- function to have a flag or a Uint attribute to identify it. ??? + + Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form); + + if Present (Alloc_Form_Exp) then + pragma Assert (Alloc_Form = Unspecified); + + Alloc_Form_Actual := Alloc_Form_Exp; + + else + pragma Assert (Alloc_Form /= Unspecified); + + Alloc_Form_Actual := + Make_Integer_Literal (Loc, + Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form))); + end if; + + Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call + (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual); + end Add_Alloc_Form_Actual_To_Build_In_Place_Call; + + ------------------------------ + -- Add_Extra_Actual_To_Call -- + ------------------------------ + + procedure Add_Extra_Actual_To_Call + (Subprogram_Call : Node_Id; + Extra_Formal : Entity_Id; + Extra_Actual : Node_Id) + is + Loc : constant Source_Ptr := Sloc (Subprogram_Call); + Param_Assoc : Node_Id; + + begin + Param_Assoc := + Make_Parameter_Association (Loc, + Selector_Name => New_Occurrence_Of (Extra_Formal, Loc), + Explicit_Actual_Parameter => Extra_Actual); + + Set_Parent (Param_Assoc, Subprogram_Call); + Set_Parent (Extra_Actual, Param_Assoc); + + if Present (Parameter_Associations (Subprogram_Call)) then + if Nkind (Last (Parameter_Associations (Subprogram_Call))) = + N_Parameter_Association + then + + -- Find last named actual, and append + + declare + L : Node_Id; + begin + L := First_Actual (Subprogram_Call); + while Present (L) loop + if No (Next_Actual (L)) then + Set_Next_Named_Actual (Parent (L), Extra_Actual); + exit; + end if; + Next_Actual (L); + end loop; + end; + + else + Set_First_Named_Actual (Subprogram_Call, Extra_Actual); + end if; + + Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call)); + + else + Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc)); + Set_First_Named_Actual (Subprogram_Call, Extra_Actual); + end if; + end Add_Extra_Actual_To_Call; + + -------------------------------------------------- + -- Add_Final_List_Actual_To_Build_In_Place_Call -- + -------------------------------------------------- + + procedure Add_Final_List_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Acc_Type : Entity_Id) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Final_List : Node_Id; + Final_List_Actual : Node_Id; + Final_List_Formal : Node_Id; + + begin + -- No such extra parameter is needed if there are no controlled parts. + -- The test for Controlled_Type accounts for class-wide results (which + -- potentially have controlled parts, even if the root type doesn't), + -- and the test for a tagged result type is needed because calls to + -- such a function can in general occur in dispatching contexts, which + -- must be treated the same as a call to class-wide functions. Both of + -- these situations require that a finalization list be passed. + + if not Controlled_Type (Underlying_Type (Etype (Function_Id))) + and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id))) + then + return; + end if; + + -- Locate implicit finalization list parameter in the called function + + Final_List_Formal := Build_In_Place_Formal (Function_Id, BIP_Final_List); + + -- Create the actual which is a pointer to the appropriate finalization + -- list. Acc_Type is present if and only if this call is the + -- initialization of an allocator. Use the Current_Scope or the Acc_Type + -- as appropriate. + + if Present (Acc_Type) + and then (Ekind (Acc_Type) = E_Anonymous_Access_Type + or else + Present (Associated_Final_Chain (Base_Type (Acc_Type)))) + then + Final_List := Find_Final_List (Acc_Type); + else + Final_List := Find_Final_List (Current_Scope); + end if; + + Final_List_Actual := + Make_Attribute_Reference (Loc, + Prefix => Final_List, + Attribute_Name => Name_Unrestricted_Access); + + Analyze_And_Resolve (Final_List_Actual, Etype (Final_List_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call + (Function_Call, Final_List_Formal, Final_List_Actual); + end Add_Final_List_Actual_To_Build_In_Place_Call; + + --------------------------------------------- + -- Add_Task_Actuals_To_Build_In_Place_Call -- + --------------------------------------------- + + procedure Add_Task_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Master_Actual : Node_Id) + -- Note: Master_Actual can be Empty, but only if there are no tasks + is + Loc : constant Source_Ptr := Sloc (Function_Call); + + begin + -- No such extra parameters are needed if there are no tasks + + if not Has_Task (Etype (Function_Id)) then + return; + end if; + + -- The master + + declare + Master_Formal : Node_Id; + begin + -- Locate implicit master parameter in the called function + + Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Master); + + Analyze_And_Resolve (Master_Actual, Etype (Master_Formal)); + + -- Build the parameter association for the new actual and add it to + -- the end of the function's actuals. + + Add_Extra_Actual_To_Call + (Function_Call, Master_Formal, Master_Actual); + end; + + -- The activation chain + + declare + Activation_Chain_Actual : Node_Id; + Activation_Chain_Formal : Node_Id; + begin + -- Locate implicit activation chain parameter in the called function + + Activation_Chain_Formal := Build_In_Place_Formal + (Function_Id, BIP_Activation_Chain); + + -- Create the actual which is a pointer to the current activation + -- chain + + Activation_Chain_Actual := + Make_Attribute_Reference (Loc, + Prefix => Make_Identifier (Loc, Name_uChain), + Attribute_Name => Name_Unrestricted_Access); + + Analyze_And_Resolve + (Activation_Chain_Actual, Etype (Activation_Chain_Formal)); + + -- Build the parameter association for the new actual and add it to + -- the end of the function's actuals. + + Add_Extra_Actual_To_Call + (Function_Call, Activation_Chain_Formal, Activation_Chain_Actual); + end; + end Add_Task_Actuals_To_Build_In_Place_Call; + + ----------------------- + -- BIP_Formal_Suffix -- + ----------------------- + + function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is + begin + case Kind is + when BIP_Alloc_Form => + return "BIPalloc"; + when BIP_Final_List => + return "BIPfinallist"; + when BIP_Master => + return "BIPmaster"; + when BIP_Activation_Chain => + return "BIPactivationchain"; + when BIP_Object_Access => + return "BIPaccess"; + end case; + end BIP_Formal_Suffix; + + --------------------------- + -- Build_In_Place_Formal -- + --------------------------- + + function Build_In_Place_Formal + (Func : Entity_Id; + Kind : BIP_Formal_Kind) return Entity_Id + is + Extra_Formal : Entity_Id := Extra_Formals (Func); + + begin + -- Maybe it would be better for each implicit formal of a build-in-place + -- function to have a flag or a Uint attribute to identify it. ??? + + loop + pragma Assert (Present (Extra_Formal)); + exit when + Chars (Extra_Formal) = + New_External_Name (Chars (Func), BIP_Formal_Suffix (Kind)); + Next_Formal_With_Extras (Extra_Formal); + end loop; + + return Extra_Formal; + end Build_In_Place_Formal; + + -------------------------------- + -- Check_Overriding_Operation -- + -------------------------------- + + procedure Check_Overriding_Operation (Subp : Entity_Id) is + Typ : constant Entity_Id := Find_Dispatching_Type (Subp); + Op_List : constant Elist_Id := Primitive_Operations (Typ); + Op_Elmt : Elmt_Id; + Prim_Op : Entity_Id; + Par_Op : Entity_Id; + + begin + if Is_Derived_Type (Typ) + and then not Is_Private_Type (Typ) + and then In_Open_Scopes (Scope (Etype (Typ))) + and then Typ = Base_Type (Typ) + then + -- Subp overrides an inherited private operation if there is an + -- inherited operation with a different name than Subp (see + -- Derive_Subprogram) whose Alias is a hidden subprogram with the + -- same name as Subp. + + Op_Elmt := First_Elmt (Op_List); + while Present (Op_Elmt) loop + Prim_Op := Node (Op_Elmt); + Par_Op := Alias (Prim_Op); + + if Present (Par_Op) + and then not Comes_From_Source (Prim_Op) + and then Chars (Prim_Op) /= Chars (Par_Op) + and then Chars (Par_Op) = Chars (Subp) + and then Is_Hidden (Par_Op) + and then Type_Conformant (Prim_Op, Subp) + then + Set_DT_Position (Subp, DT_Position (Prim_Op)); + end if; + + Next_Elmt (Op_Elmt); + end loop; + end if; + end Check_Overriding_Operation; + + ------------------------------- + -- Detect_Infinite_Recursion -- + ------------------------------- + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + + Var_List : constant Elist_Id := New_Elmt_List; + -- List of globals referenced by body of procedure + + Call_List : constant Elist_Id := New_Elmt_List; + -- List of recursive calls in body of procedure + + Shad_List : constant Elist_Id := New_Elmt_List; + -- List of entity id's for entities created to capture the value of + -- referenced globals on entry to the procedure. + + Scop : constant Uint := Scope_Depth (Spec); + -- This is used to record the scope depth of the current procedure, so + -- that we can identify global references. + + Max_Vars : constant := 4; + -- Do not test more than four global variables + + Count_Vars : Natural := 0; + -- Count variables found so far + + Var : Entity_Id; + Elm : Elmt_Id; + Ent : Entity_Id; + Call : Elmt_Id; + Decl : Node_Id; + Test : Node_Id; + Elm1 : Elmt_Id; + Elm2 : Elmt_Id; + Last : Node_Id; + + function Process (Nod : Node_Id) return Traverse_Result; + -- Function to traverse the subprogram body (using Traverse_Func) + + ------------- + -- Process -- + ------------- + + function Process (Nod : Node_Id) return Traverse_Result is + begin + -- Procedure call + + if Nkind (Nod) = N_Procedure_Call_Statement then + + -- Case of one of the detected recursive calls + + if Is_Entity_Name (Name (Nod)) + and then Has_Recursive_Call (Entity (Name (Nod))) + and then Entity (Name (Nod)) = Spec + then + Append_Elmt (Nod, Call_List); + return Skip; + + -- Any other procedure call may have side effects + + else + return Abandon; + end if; + + -- A call to a pure function can always be ignored + + elsif Nkind (Nod) = N_Function_Call + and then Is_Entity_Name (Name (Nod)) + and then Is_Pure (Entity (Name (Nod))) + then + return Skip; + + -- Case of an identifier reference + + elsif Nkind (Nod) = N_Identifier then + Ent := Entity (Nod); + + -- If no entity, then ignore the reference + + -- Not clear why this can happen. To investigate, remove this + -- test and look at the crash that occurs here in 3401-004 ??? + + if No (Ent) then + return Skip; + + -- Ignore entities with no Scope, again not clear how this + -- can happen, to investigate, look at 4108-008 ??? + + elsif No (Scope (Ent)) then + return Skip; + + -- Ignore the reference if not to a more global object + + elsif Scope_Depth (Scope (Ent)) >= Scop then + return Skip; + + -- References to types, exceptions and constants are always OK + + elsif Is_Type (Ent) + or else Ekind (Ent) = E_Exception + or else Ekind (Ent) = E_Constant + then + return Skip; + + -- If other than a non-volatile scalar variable, we have some + -- kind of global reference (e.g. to a function) that we cannot + -- deal with so we forget the attempt. + + elsif Ekind (Ent) /= E_Variable + or else not Is_Scalar_Type (Etype (Ent)) + or else Treat_As_Volatile (Ent) + then + return Abandon; + + -- Otherwise we have a reference to a global scalar + + else + -- Loop through global entities already detected + + Elm := First_Elmt (Var_List); + loop + -- If not detected before, record this new global reference + + if No (Elm) then + Count_Vars := Count_Vars + 1; + + if Count_Vars <= Max_Vars then + Append_Elmt (Entity (Nod), Var_List); + else + return Abandon; + end if; + + exit; + + -- If recorded before, ignore + + elsif Node (Elm) = Entity (Nod) then + return Skip; + + -- Otherwise keep looking + + else + Next_Elmt (Elm); + end if; + end loop; + + return Skip; + end if; + + -- For all other node kinds, recursively visit syntactic children + + else + return OK; + end if; + end Process; + + function Traverse_Body is new Traverse_Func (Process); + + -- Start of processing for Detect_Infinite_Recursion + + begin + -- Do not attempt detection in No_Implicit_Conditional mode, since we + -- won't be able to generate the code to handle the recursion in any + -- case. + + if Restriction_Active (No_Implicit_Conditionals) then + return; + end if; + + -- Otherwise do traversal and quit if we get abandon signal + + if Traverse_Body (N) = Abandon then + return; + + -- We must have a call, since Has_Recursive_Call was set. If not just + -- ignore (this is only an error check, so if we have a funny situation, + -- due to bugs or errors, we do not want to bomb!) + + elsif Is_Empty_Elmt_List (Call_List) then + return; + end if; + + -- Here is the case where we detect recursion at compile time + + -- Push our current scope for analyzing the declarations and code that + -- we will insert for the checking. + + Push_Scope (Spec); + + -- This loop builds temporary variables for each of the referenced + -- globals, so that at the end of the loop the list Shad_List contains + -- these temporaries in one-to-one correspondence with the elements in + -- Var_List. + + Last := Empty; + Elm := First_Elmt (Var_List); + while Present (Elm) loop + Var := Node (Elm); + Ent := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('S')); + Append_Elmt (Ent, Shad_List); + + -- Insert a declaration for this temporary at the start of the + -- declarations for the procedure. The temporaries are declared as + -- constant objects initialized to the current values of the + -- corresponding temporaries. + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => New_Occurrence_Of (Etype (Var), Loc), + Constant_Present => True, + Expression => New_Occurrence_Of (Var, Loc)); + + if No (Last) then + Prepend (Decl, Declarations (N)); + else + Insert_After (Last, Decl); + end if; + + Last := Decl; + Analyze (Decl); + Next_Elmt (Elm); + end loop; + + -- Loop through calls + + Call := First_Elmt (Call_List); + while Present (Call) loop + + -- Build a predicate expression of the form + + -- True + -- and then global1 = temp1 + -- and then global2 = temp2 + -- ... + + -- This predicate determines if any of the global values + -- referenced by the procedure have changed since the + -- current call, if not an infinite recursion is assured. + + Test := New_Occurrence_Of (Standard_True, Loc); + + Elm1 := First_Elmt (Var_List); + Elm2 := First_Elmt (Shad_List); + while Present (Elm1) loop + Test := + Make_And_Then (Loc, + Left_Opnd => Test, + Right_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc), + Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc))); + + Next_Elmt (Elm1); + Next_Elmt (Elm2); + end loop; + + -- Now we replace the call with the sequence + + -- if no-changes (see above) then + -- raise Storage_Error; + -- else + -- original-call + -- end if; + + Rewrite (Node (Call), + Make_If_Statement (Loc, + Condition => Test, + Then_Statements => New_List ( + Make_Raise_Storage_Error (Loc, + Reason => SE_Infinite_Recursion)), + + Else_Statements => New_List ( + Relocate_Node (Node (Call))))); + + Analyze (Node (Call)); + + Next_Elmt (Call); + end loop; + + -- Remove temporary scope stack entry used for analysis + + Pop_Scope; + end Detect_Infinite_Recursion; + + -------------------- + -- Expand_Actuals -- + -------------------- + + procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + Actual : Node_Id; + Formal : Entity_Id; + N_Node : Node_Id; + Post_Call : List_Id; + E_Formal : Entity_Id; + + procedure Add_Call_By_Copy_Code; + -- For cases where the parameter must be passed by copy, this routine + -- generates a temporary variable into which the actual is copied and + -- then passes this as the parameter. For an OUT or IN OUT parameter, + -- an assignment is also generated to copy the result back. The call + -- also takes care of any constraint checks required for the type + -- conversion case (on both the way in and the way out). + + procedure Add_Simple_Call_By_Copy_Code; + -- This is similar to the above, but is used in cases where we know + -- that all that is needed is to simply create a temporary and copy + -- the value in and out of the temporary. + + procedure Check_Fortran_Logical; + -- A value of type Logical that is passed through a formal parameter + -- must be normalized because .TRUE. usually does not have the same + -- representation as True. We assume that .FALSE. = False = 0. + -- What about functions that return a logical type ??? + + function Is_Legal_Copy return Boolean; + -- Check that an actual can be copied before generating the temporary + -- to be used in the call. If the actual is of a by_reference type then + -- the program is illegal (this can only happen in the presence of + -- rep. clauses that force an incorrect alignment). If the formal is + -- a by_reference parameter imposed by a DEC pragma, emit a warning to + -- the effect that this might lead to unaligned arguments. + + function Make_Var (Actual : Node_Id) return Entity_Id; + -- Returns an entity that refers to the given actual parameter, + -- Actual (not including any type conversion). If Actual is an + -- entity name, then this entity is returned unchanged, otherwise + -- a renaming is created to provide an entity for the actual. + + procedure Reset_Packed_Prefix; + -- The expansion of a packed array component reference is delayed in + -- the context of a call. Now we need to complete the expansion, so we + -- unmark the analyzed bits in all prefixes. + + --------------------------- + -- Add_Call_By_Copy_Code -- + --------------------------- + + procedure Add_Call_By_Copy_Code is + Expr : Node_Id; + Init : Node_Id; + Temp : Entity_Id; + Indic : Node_Id; + Var : Entity_Id; + F_Typ : constant Entity_Id := Etype (Formal); + V_Typ : Entity_Id; + Crep : Boolean; + + begin + if not Is_Legal_Copy then + return; + end if; + + Temp := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('T')); + + -- Use formal type for temp, unless formal type is an unconstrained + -- array, in which case we don't have to worry about bounds checks, + -- and we use the actual type, since that has appropriate bounds. + + if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + else + Indic := New_Occurrence_Of (Etype (Formal), Loc); + end if; + + if Nkind (Actual) = N_Type_Conversion then + V_Typ := Etype (Expression (Actual)); + + -- If the formal is an (in-)out parameter, capture the name + -- of the variable in order to build the post-call assignment. + + Var := Make_Var (Expression (Actual)); + + Crep := not Same_Representation + (F_Typ, Etype (Expression (Actual))); + + else + V_Typ := Etype (Actual); + Var := Make_Var (Actual); + Crep := False; + end if; + + -- Setup initialization for case of in out parameter, or an out + -- parameter where the formal is an unconstrained array (in the + -- latter case, we have to pass in an object with bounds). + + -- If this is an out parameter, the initial copy is wasteful, so as + -- an optimization for the one-dimensional case we extract the + -- bounds of the actual and build an uninitialized temporary of the + -- right size. + + if Ekind (Formal) = E_In_Out_Parameter + or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ)) + then + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + + elsif Ekind (Formal) = E_Out_Parameter + and then Is_Array_Type (F_Typ) + and then Number_Dimensions (F_Typ) = 1 + and then not Has_Non_Null_Base_Init_Proc (F_Typ) + then + -- Actual is a one-dimensional array or slice, and the type + -- requires no initialization. Create a temporary of the + -- right size, but do not copy actual into it (optimization). + + Init := Empty; + Indic := + Make_Subtype_Indication (Loc, + Subtype_Mark => + New_Occurrence_Of (F_Typ, Loc), + Constraint => + Make_Index_Or_Discriminant_Constraint (Loc, + Constraints => New_List ( + Make_Range (Loc, + Low_Bound => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Var, Loc), + Attribute_name => Name_First), + High_Bound => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Var, Loc), + Attribute_Name => Name_Last))))); + + else + Init := New_Occurrence_Of (Var, Loc); + end if; + + -- An initialization is created for packed conversions as + -- actuals for out parameters to enable Make_Object_Declaration + -- to determine the proper subtype for N_Node. Note that this + -- is wasteful because the extra copying on the call side is + -- not required for such out parameters. ??? + + elsif Ekind (Formal) = E_Out_Parameter + and then Nkind (Actual) = N_Type_Conversion + and then (Is_Bit_Packed_Array (F_Typ) + or else + Is_Bit_Packed_Array (Etype (Expression (Actual)))) + then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + + elsif Ekind (Formal) = E_In_Parameter then + + -- Handle the case in which the actual is a type conversion + + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + else + Init := New_Occurrence_Of (Var, Loc); + end if; + + else + Init := Empty; + end if; + + N_Node := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => Indic, + Expression => Init); + Set_Assignment_OK (N_Node); + Insert_Action (N, N_Node); + + -- Now, normally the deal here is that we use the defining + -- identifier created by that object declaration. There is + -- one exception to this. In the change of representation case + -- the above declaration will end up looking like: + + -- temp : type := identifier; + + -- And in this case we might as well use the identifier directly + -- and eliminate the temporary. Note that the analysis of the + -- declaration was not a waste of time in that case, since it is + -- what generated the necessary change of representation code. If + -- the change of representation introduced additional code, as in + -- a fixed-integer conversion, the expression is not an identifier + -- and must be kept. + + if Crep + and then Present (Expression (N_Node)) + and then Is_Entity_Name (Expression (N_Node)) + then + Temp := Entity (Expression (N_Node)); + Rewrite (N_Node, Make_Null_Statement (Loc)); + end if; + + -- For IN parameter, all we do is to replace the actual + + if Ekind (Formal) = E_In_Parameter then + Rewrite (Actual, New_Reference_To (Temp, Loc)); + Analyze (Actual); + + -- Processing for OUT or IN OUT parameter + + else + -- Kill current value indications for the temporary variable we + -- created, since we just passed it as an OUT parameter. + + Kill_Current_Values (Temp); + + -- If type conversion, use reverse conversion on exit + + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + else + Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + end if; + else + Expr := New_Occurrence_Of (Temp, Loc); + end if; + + Rewrite (Actual, New_Reference_To (Temp, Loc)); + Analyze (Actual); + + -- If the actual is a conversion of a packed reference, it may + -- already have been expanded by Remove_Side_Effects, and the + -- resulting variable is a temporary which does not designate + -- the proper out-parameter, which may not be addressable. In + -- that case, generate an assignment to the original expression + -- (before expansion of the packed reference) so that the proper + -- expansion of assignment to a packed component can take place. + + declare + Obj : Node_Id; + Lhs : Node_Id; + + begin + if Is_Renaming_Of_Object (Var) + and then Nkind (Renamed_Object (Var)) = N_Selected_Component + and then Is_Entity_Name (Prefix (Renamed_Object (Var))) + and then Nkind (Original_Node (Prefix (Renamed_Object (Var)))) + = N_Indexed_Component + and then + Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var)))) + then + Obj := Renamed_Object (Var); + Lhs := + Make_Selected_Component (Loc, + Prefix => + New_Copy_Tree (Original_Node (Prefix (Obj))), + Selector_Name => New_Copy (Selector_Name (Obj))); + Reset_Analyzed_Flags (Lhs); + + else + Lhs := New_Occurrence_Of (Var, Loc); + end if; + + Set_Assignment_OK (Lhs); + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Expr)); + end; + end if; + + end Add_Call_By_Copy_Code; + + ---------------------------------- + -- Add_Simple_Call_By_Copy_Code -- + ---------------------------------- + + procedure Add_Simple_Call_By_Copy_Code is + Temp : Entity_Id; + Decl : Node_Id; + Incod : Node_Id; + Outcod : Node_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Indic : Node_Id; + F_Typ : constant Entity_Id := Etype (Formal); + + begin + if not Is_Legal_Copy then + return; + end if; + + -- Use formal type for temp, unless formal type is an unconstrained + -- array, in which case we don't have to worry about bounds checks, + -- and we use the actual type, since that has appropriate bounds. + + if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + else + Indic := New_Occurrence_Of (Etype (Formal), Loc); + end if; + + -- Prepare to generate code + + Reset_Packed_Prefix; + + Temp := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('T')); + Incod := Relocate_Node (Actual); + Outcod := New_Copy_Tree (Incod); + + -- Generate declaration of temporary variable, initializing it + -- with the input parameter unless we have an OUT formal or + -- this is an initialization call. + + -- If the formal is an out parameter with discriminants, the + -- discriminants must be captured even if the rest of the object + -- is in principle uninitialized, because the discriminants may + -- be read by the called subprogram. + + if Ekind (Formal) = E_Out_Parameter then + Incod := Empty; + + if Has_Discriminants (Etype (Formal)) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + end if; + + elsif Inside_Init_Proc then + + -- Could use a comment here to match comment below ??? + + if Nkind (Actual) /= N_Selected_Component + or else + not Has_Discriminant_Dependent_Constraint + (Entity (Selector_Name (Actual))) + then + Incod := Empty; + + -- Otherwise, keep the component in order to generate the proper + -- actual subtype, that depends on enclosing discriminants. + + else + null; + end if; + end if; + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => Indic, + Expression => Incod); + + if Inside_Init_Proc + and then No (Incod) + then + -- If the call is to initialize a component of a composite type, + -- and the component does not depend on discriminants, use the + -- actual type of the component. This is required in case the + -- component is constrained, because in general the formal of the + -- initialization procedure will be unconstrained. Note that if + -- the component being initialized is constrained by an enclosing + -- discriminant, the presence of the initialization in the + -- declaration will generate an expression for the actual subtype. + + Set_No_Initialization (Decl); + Set_Object_Definition (Decl, + New_Occurrence_Of (Etype (Actual), Loc)); + end if; + + Insert_Action (N, Decl); + + -- The actual is simply a reference to the temporary + + Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); + + -- Generate copy out if OUT or IN OUT parameter + + if Ekind (Formal) /= E_In_Parameter then + Lhs := Outcod; + Rhs := New_Occurrence_Of (Temp, Loc); + + -- Deal with conversion + + if Nkind (Lhs) = N_Type_Conversion then + Lhs := Expression (Lhs); + Rhs := Convert_To (Etype (Actual), Rhs); + end if; + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Rhs)); + Set_Assignment_OK (Name (Last (Post_Call))); + end if; + end Add_Simple_Call_By_Copy_Code; + + --------------------------- + -- Check_Fortran_Logical -- + --------------------------- + + procedure Check_Fortran_Logical is + Logical : constant Entity_Id := Etype (Formal); + Var : Entity_Id; + + -- Note: this is very incomplete, e.g. it does not handle arrays + -- of logical values. This is really not the right approach at all???) + + begin + if Convention (Subp) = Convention_Fortran + and then Root_Type (Etype (Formal)) = Standard_Boolean + and then Ekind (Formal) /= E_In_Parameter + then + Var := Make_Var (Actual); + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Var, Loc), + Expression => + Unchecked_Convert_To ( + Logical, + Make_Op_Ne (Loc, + Left_Opnd => New_Occurrence_Of (Var, Loc), + Right_Opnd => + Unchecked_Convert_To ( + Logical, + New_Occurrence_Of (Standard_False, Loc)))))); + end if; + end Check_Fortran_Logical; + + ------------------- + -- Is_Legal_Copy -- + ------------------- + + function Is_Legal_Copy return Boolean is + begin + -- An attempt to copy a value of such a type can only occur if + -- representation clauses give the actual a misaligned address. + + if Is_By_Reference_Type (Etype (Formal)) then + Error_Msg_N + ("misaligned actual cannot be passed by reference", Actual); + return False; + + -- For users of Starlet, we assume that the specification of by- + -- reference mechanism is mandatory. This may lead to unaligned + -- objects but at least for DEC legacy code it is known to work. + -- The warning will alert users of this code that a problem may + -- be lurking. + + elsif Mechanism (Formal) = By_Reference + and then Is_Valued_Procedure (Scope (Formal)) + then + Error_Msg_N + ("by_reference actual may be misaligned?", Actual); + return False; + + else + return True; + end if; + end Is_Legal_Copy; + + -------------- + -- Make_Var -- + -------------- + + function Make_Var (Actual : Node_Id) return Entity_Id is + Var : Entity_Id; + + begin + if Is_Entity_Name (Actual) then + return Entity (Actual); + + else + Var := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('T')); + + N_Node := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Var, + Subtype_Mark => + New_Occurrence_Of (Etype (Actual), Loc), + Name => Relocate_Node (Actual)); + + Insert_Action (N, N_Node); + return Var; + end if; + end Make_Var; + + ------------------------- + -- Reset_Packed_Prefix -- + ------------------------- + + procedure Reset_Packed_Prefix is + Pfx : Node_Id := Actual; + begin + loop + Set_Analyzed (Pfx, False); + exit when + not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component); + Pfx := Prefix (Pfx); + end loop; + end Reset_Packed_Prefix; + + -- Start of processing for Expand_Actuals + + begin + Post_Call := New_List; + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + while Present (Formal) loop + E_Formal := Etype (Formal); + + if Is_Scalar_Type (E_Formal) + or else Nkind (Actual) = N_Slice + then + Check_Fortran_Logical; + + -- RM 6.4.1 (11) + + elsif Ekind (Formal) /= E_Out_Parameter then + + -- The unusual case of the current instance of a protected type + -- requires special handling. This can only occur in the context + -- of a call within the body of a protected operation. + + if Is_Entity_Name (Actual) + and then Ekind (Entity (Actual)) = E_Protected_Type + and then In_Open_Scopes (Entity (Actual)) + then + if Scope (Subp) /= Entity (Actual) then + Error_Msg_N ("operation outside protected type may not " + & "call back its protected operations?", Actual); + end if; + + Rewrite (Actual, + Expand_Protected_Object_Reference (N, Entity (Actual))); + end if; + + -- Ada 2005 (AI-318-02): If the actual parameter is a call to a + -- build-in-place function, then a temporary return object needs + -- to be created and access to it must be passed to the function. + -- Currently we limit such functions to those with inherently + -- limited result subtypes, but eventually we plan to expand the + -- functions that are treated as build-in-place to include other + -- composite result types. + + if Ada_Version >= Ada_05 + and then Is_Build_In_Place_Function_Call (Actual) + then + Make_Build_In_Place_Call_In_Anonymous_Context (Actual); + end if; + + Apply_Constraint_Check (Actual, E_Formal); + + -- Out parameter case. No constraint checks on access type + -- RM 6.4.1 (13) + + elsif Is_Access_Type (E_Formal) then + null; + + -- RM 6.4.1 (14) + + elsif Has_Discriminants (Base_Type (E_Formal)) + or else Has_Non_Null_Base_Init_Proc (E_Formal) + then + Apply_Constraint_Check (Actual, E_Formal); + + -- RM 6.4.1 (15) + + else + Apply_Constraint_Check (Actual, Base_Type (E_Formal)); + end if; + + -- Processing for IN-OUT and OUT parameters + + if Ekind (Formal) /= E_In_Parameter then + + -- For type conversions of arrays, apply length/range checks + + if Is_Array_Type (E_Formal) + and then Nkind (Actual) = N_Type_Conversion + then + if Is_Constrained (E_Formal) then + Apply_Length_Check (Expression (Actual), E_Formal); + else + Apply_Range_Check (Expression (Actual), E_Formal); + end if; + end if; + + -- If argument is a type conversion for a type that is passed + -- by copy, then we must pass the parameter by copy. + + if Nkind (Actual) = N_Type_Conversion + and then + (Is_Numeric_Type (E_Formal) + or else Is_Access_Type (E_Formal) + or else Is_Enumeration_Type (E_Formal) + or else Is_Bit_Packed_Array (Etype (Formal)) + or else Is_Bit_Packed_Array (Etype (Expression (Actual))) + + -- Also pass by copy if change of representation + + or else not Same_Representation + (Etype (Formal), + Etype (Expression (Actual)))) + then + Add_Call_By_Copy_Code; + + -- References to components of bit packed arrays are expanded + -- at this point, rather than at the point of analysis of the + -- actuals, to handle the expansion of the assignment to + -- [in] out parameters. + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Simple_Call_By_Copy_Code; + + -- If a non-scalar actual is possibly bit-aligned, we need a copy + -- because the back-end cannot cope with such objects. In other + -- cases where alignment forces a copy, the back-end generates + -- it properly. It should not be generated unconditionally in the + -- front-end because it does not know precisely the alignment + -- requirements of the target, and makes too conservative an + -- estimate, leading to superfluous copies or spurious errors + -- on by-reference parameters. + + elsif Nkind (Actual) = N_Selected_Component + and then + Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual))) + and then not Represented_As_Scalar (Etype (Formal)) + then + Add_Simple_Call_By_Copy_Code; + + -- References to slices of bit packed arrays are expanded + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- References to possibly unaligned slices of arrays are expanded + + elsif Is_Possibly_Unaligned_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- Deal with access types where the actual subtype and the + -- formal subtype are not the same, requiring a check. + + -- It is necessary to exclude tagged types because of "downward + -- conversion" errors and a strange assertion error in namet + -- from gnatf in bug 1215-001 ??? + + elsif Is_Access_Type (E_Formal) + and then not Same_Type (E_Formal, Etype (Actual)) + and then not Is_Tagged_Type (Designated_Type (E_Formal)) + then + Add_Call_By_Copy_Code; + + -- If the actual is not a scalar and is marked for volatile + -- treatment, whereas the formal is not volatile, then pass + -- by copy unless it is a by-reference type. + + elsif Is_Entity_Name (Actual) + and then Treat_As_Volatile (Entity (Actual)) + and then not Is_By_Reference_Type (Etype (Actual)) + and then not Is_Scalar_Type (Etype (Entity (Actual))) + and then not Treat_As_Volatile (E_Formal) + then + Add_Call_By_Copy_Code; + + elsif Nkind (Actual) = N_Indexed_Component + and then Is_Entity_Name (Prefix (Actual)) + and then Has_Volatile_Components (Entity (Prefix (Actual))) + then + Add_Call_By_Copy_Code; + end if; + + -- Processing for IN parameters + + else + -- For IN parameters is in the packed array case, we expand an + -- indexed component (the circuit in Exp_Ch4 deliberately left + -- indexed components appearing as actuals untouched, so that + -- the special processing above for the OUT and IN OUT cases + -- could be performed. We could make the test in Exp_Ch4 more + -- complex and have it detect the parameter mode, but it is + -- easier simply to handle all cases here.) + + if Nkind (Actual) = N_Indexed_Component + and then Is_Packed (Etype (Prefix (Actual))) + then + Reset_Packed_Prefix; + Expand_Packed_Element_Reference (Actual); + + -- If we have a reference to a bit packed array, we copy it, + -- since the actual must be byte aligned. + + -- Is this really necessary in all cases??? + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Simple_Call_By_Copy_Code; + + -- If a non-scalar actual is possibly unaligned, we need a copy + + elsif Is_Possibly_Unaligned_Object (Actual) + and then not Represented_As_Scalar (Etype (Formal)) + then + Add_Simple_Call_By_Copy_Code; + + -- Similarly, we have to expand slices of packed arrays here + -- because the result must be byte aligned. + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- Only processing remaining is to pass by copy if this is a + -- reference to a possibly unaligned slice, since the caller + -- expects an appropriately aligned argument. + + elsif Is_Possibly_Unaligned_Slice (Actual) then + Add_Call_By_Copy_Code; + end if; + end if; + + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- Find right place to put post call stuff if it is present + + if not Is_Empty_List (Post_Call) then + + -- If call is not a list member, it must be the triggering statement + -- of a triggering alternative or an entry call alternative, and we + -- can add the post call stuff to the corresponding statement list. + + if not Is_List_Member (N) then + declare + P : constant Node_Id := Parent (N); + + begin + pragma Assert (Nkind_In (P, N_Triggering_Alternative, + N_Entry_Call_Alternative)); + + if Is_Non_Empty_List (Statements (P)) then + Insert_List_Before_And_Analyze + (First (Statements (P)), Post_Call); + else + Set_Statements (P, Post_Call); + end if; + end; + + -- Otherwise, normal case where N is in a statement sequence, + -- just put the post-call stuff after the call statement. + + else + Insert_Actions_After (N, Post_Call); + end if; + end if; + + -- The call node itself is re-analyzed in Expand_Call + + end Expand_Actuals; + + ----------------- + -- Expand_Call -- + ----------------- + + -- This procedure handles expansion of function calls and procedure call + -- statements (i.e. it serves as the body for Expand_N_Function_Call and + -- Expand_N_Procedure_Call_Statement. Processing for calls includes: + + -- Replace call to Raise_Exception by Raise_Exception always if possible + -- Provide values of actuals for all formals in Extra_Formals list + -- Replace "call" to enumeration literal function by literal itself + -- Rewrite call to predefined operator as operator + -- Replace actuals to in-out parameters that are numeric conversions, + -- with explicit assignment to temporaries before and after the call. + -- Remove optional actuals if First_Optional_Parameter specified. + + -- Note that the list of actuals has been filled with default expressions + -- during semantic analysis of the call. Only the extra actuals required + -- for the 'Constrained attribute and for accessibility checks are added + -- at this point. + + procedure Expand_Call (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Extra_Actuals : List_Id := No_List; + Prev : Node_Id := Empty; + + procedure Add_Actual_Parameter (Insert_Param : Node_Id); + -- Adds one entry to the end of the actual parameter list. Used for + -- default parameters and for extra actuals (for Extra_Formals). The + -- argument is an N_Parameter_Association node. + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id); + -- Adds an extra actual to the list of extra actuals. Expr is the + -- expression for the value of the actual, EF is the entity for the + -- extra formal. + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id; + -- Within an instance, a type derived from a non-tagged formal derived + -- type inherits from the original parent, not from the actual. This is + -- tested in 4723-003. The current derivation mechanism has the derived + -- type inherit from the actual, which is only correct outside of the + -- instance. If the subprogram is inherited, we test for this particular + -- case through a convoluted tree traversal before setting the proper + -- subprogram to be called. + + -------------------------- + -- Add_Actual_Parameter -- + -------------------------- + + procedure Add_Actual_Parameter (Insert_Param : Node_Id) is + Actual_Expr : constant Node_Id := + Explicit_Actual_Parameter (Insert_Param); + + begin + -- Case of insertion is first named actual + + if No (Prev) or else + Nkind (Parent (Prev)) /= N_Parameter_Association + then + Set_Next_Named_Actual (Insert_Param, First_Named_Actual (N)); + Set_First_Named_Actual (N, Actual_Expr); + + if No (Prev) then + if No (Parameter_Associations (N)) then + Set_Parameter_Associations (N, New_List); + Append (Insert_Param, Parameter_Associations (N)); + end if; + else + Insert_After (Prev, Insert_Param); + end if; + + -- Case of insertion is not first named actual + + else + Set_Next_Named_Actual + (Insert_Param, Next_Named_Actual (Parent (Prev))); + Set_Next_Named_Actual (Parent (Prev), Actual_Expr); + Append (Insert_Param, Parameter_Associations (N)); + end if; + + Prev := Actual_Expr; + end Add_Actual_Parameter; + + ---------------------- + -- Add_Extra_Actual -- + ---------------------- + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is + Loc : constant Source_Ptr := Sloc (Expr); + + begin + if Extra_Actuals = No_List then + Extra_Actuals := New_List; + Set_Parent (Extra_Actuals, N); + end if; + + Append_To (Extra_Actuals, + Make_Parameter_Association (Loc, + Explicit_Actual_Parameter => Expr, + Selector_Name => + Make_Identifier (Loc, Chars (EF)))); + + Analyze_And_Resolve (Expr, Etype (EF)); + end Add_Extra_Actual; + + --------------------------- + -- Inherited_From_Formal -- + --------------------------- + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id is + Par : Entity_Id; + Gen_Par : Entity_Id; + Gen_Prim : Elist_Id; + Elmt : Elmt_Id; + Indic : Node_Id; + + begin + -- If the operation is inherited, it is attached to the corresponding + -- type derivation. If the parent in the derivation is a generic + -- actual, it is a subtype of the actual, and we have to recover the + -- original derived type declaration to find the proper parent. + + if Nkind (Parent (S)) /= N_Full_Type_Declaration + or else not Is_Derived_Type (Defining_Identifier (Parent (S))) + or else Nkind (Type_Definition (Original_Node (Parent (S)))) /= + N_Derived_Type_Definition + or else not In_Instance + then + return Empty; + + else + Indic := + (Subtype_Indication + (Type_Definition (Original_Node (Parent (S))))); + + if Nkind (Indic) = N_Subtype_Indication then + Par := Entity (Subtype_Mark (Indic)); + else + Par := Entity (Indic); + end if; + end if; + + if not Is_Generic_Actual_Type (Par) + or else Is_Tagged_Type (Par) + or else Nkind (Parent (Par)) /= N_Subtype_Declaration + or else not In_Open_Scopes (Scope (Par)) + then + return Empty; + + else + Gen_Par := Generic_Parent_Type (Parent (Par)); + end if; + + -- If the actual has no generic parent type, the formal is not + -- a formal derived type, so nothing to inherit. + + if No (Gen_Par) then + return Empty; + end if; + + -- If the generic parent type is still the generic type, this is a + -- private formal, not a derived formal, and there are no operations + -- inherited from the formal. + + if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then + return Empty; + end if; + + Gen_Prim := Collect_Primitive_Operations (Gen_Par); + + Elmt := First_Elmt (Gen_Prim); + while Present (Elmt) loop + if Chars (Node (Elmt)) = Chars (S) then + declare + F1 : Entity_Id; + F2 : Entity_Id; + + begin + F1 := First_Formal (S); + F2 := First_Formal (Node (Elmt)); + while Present (F1) + and then Present (F2) + loop + if Etype (F1) = Etype (F2) + or else Etype (F2) = Gen_Par + then + Next_Formal (F1); + Next_Formal (F2); + else + Next_Elmt (Elmt); + exit; -- not the right subprogram + end if; + + return Node (Elmt); + end loop; + end; + + else + Next_Elmt (Elmt); + end if; + end loop; + + raise Program_Error; + end Inherited_From_Formal; + + -- Local variables + + Remote : constant Boolean := Is_Remote_Call (N); + Actual : Node_Id; + Formal : Entity_Id; + Orig_Subp : Entity_Id := Empty; + Param_Count : Natural := 0; + Parent_Formal : Entity_Id; + Parent_Subp : Entity_Id; + Scop : Entity_Id; + Subp : Entity_Id; + + Prev_Orig : Node_Id; + -- Original node for an actual, which may have been rewritten. If the + -- actual is a function call that has been transformed from a selected + -- component, the original node is unanalyzed. Otherwise, it carries + -- semantic information used to generate additional actuals. + + CW_Interface_Formals_Present : Boolean := False; + + -- Start of processing for Expand_Call + + begin + -- Ignore if previous error + + if Nkind (N) in N_Has_Etype and then Etype (N) = Any_Type then + return; + end if; + + -- Call using access to subprogram with explicit dereference + + if Nkind (Name (N)) = N_Explicit_Dereference then + Subp := Etype (Name (N)); + Parent_Subp := Empty; + + -- Case of call to simple entry, where the Name is a selected component + -- whose prefix is the task, and whose selector name is the entry name + + elsif Nkind (Name (N)) = N_Selected_Component then + Subp := Entity (Selector_Name (Name (N))); + Parent_Subp := Empty; + + -- Case of call to member of entry family, where Name is an indexed + -- component, with the prefix being a selected component giving the + -- task and entry family name, and the index being the entry index. + + elsif Nkind (Name (N)) = N_Indexed_Component then + Subp := Entity (Selector_Name (Prefix (Name (N)))); + Parent_Subp := Empty; + + -- Normal case + + else + Subp := Entity (Name (N)); + Parent_Subp := Alias (Subp); + + -- Replace call to Raise_Exception by call to Raise_Exception_Always + -- if we can tell that the first parameter cannot possibly be null. + -- This helps optimization and also generation of warnings. + + -- We do not do this if Raise_Exception_Always does not exist, which + -- can happen in configurable run time profiles which provide only a + -- Raise_Exception, which is in fact an unconditional raise anyway. + + if Is_RTE (Subp, RE_Raise_Exception) + and then RTE_Available (RE_Raise_Exception_Always) + then + declare + FA : constant Node_Id := Original_Node (First_Actual (N)); + + begin + -- The case we catch is where the first argument is obtained + -- using the Identity attribute (which must always be + -- non-null). + + if Nkind (FA) = N_Attribute_Reference + and then Attribute_Name (FA) = Name_Identity + then + Subp := RTE (RE_Raise_Exception_Always); + Set_Name (N, New_Occurrence_Of (Subp, Loc)); + end if; + end; + end if; + + if Ekind (Subp) = E_Entry then + Parent_Subp := Empty; + end if; + end if; + + -- Ada 2005 (AI-345): We have a procedure call as a triggering + -- alternative in an asynchronous select or as an entry call in + -- a conditional or timed select. Check whether the procedure call + -- is a renaming of an entry and rewrite it as an entry call. + + if Ada_Version >= Ada_05 + and then Nkind (N) = N_Procedure_Call_Statement + and then + ((Nkind (Parent (N)) = N_Triggering_Alternative + and then Triggering_Statement (Parent (N)) = N) + or else + (Nkind (Parent (N)) = N_Entry_Call_Alternative + and then Entry_Call_Statement (Parent (N)) = N)) + then + declare + Ren_Decl : Node_Id; + Ren_Root : Entity_Id := Subp; + + begin + -- This may be a chain of renamings, find the root + + if Present (Alias (Ren_Root)) then + Ren_Root := Alias (Ren_Root); + end if; + + if Present (Original_Node (Parent (Parent (Ren_Root)))) then + Ren_Decl := Original_Node (Parent (Parent (Ren_Root))); + + if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then + Rewrite (N, + Make_Entry_Call_Statement (Loc, + Name => + New_Copy_Tree (Name (Ren_Decl)), + Parameter_Associations => + New_Copy_List_Tree (Parameter_Associations (N)))); + + return; + end if; + end if; + end; + end if; + + -- First step, compute extra actuals, corresponding to any + -- Extra_Formals present. Note that we do not access Extra_Formals + -- directly, instead we simply note the presence of the extra + -- formals as we process the regular formals and collect the + -- corresponding actuals in Extra_Actuals. + + -- We also generate any required range checks for actuals as we go + -- through the loop, since this is a convenient place to do this. + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + Param_Count := 1; + while Present (Formal) loop + + -- Generate range check if required (not activated yet ???) + +-- if Do_Range_Check (Actual) then +-- Set_Do_Range_Check (Actual, False); +-- Generate_Range_Check +-- (Actual, Etype (Formal), CE_Range_Check_Failed); +-- end if; + + -- Prepare to examine current entry + + Prev := Actual; + Prev_Orig := Original_Node (Prev); + + -- The original actual may have been a call written in prefix + -- form, and rewritten before analysis. + + if not Analyzed (Prev_Orig) + and then Nkind_In (Actual, N_Function_Call, N_Identifier) + then + Prev_Orig := Prev; + end if; + + -- Ada 2005 (AI-251): Check if any formal is a class-wide interface + -- to expand it in a further round. + + CW_Interface_Formals_Present := + CW_Interface_Formals_Present + or else + (Ekind (Etype (Formal)) = E_Class_Wide_Type + and then Is_Interface (Etype (Etype (Formal)))) + or else + (Ekind (Etype (Formal)) = E_Anonymous_Access_Type + and then Is_Interface (Directly_Designated_Type + (Etype (Etype (Formal))))); + + -- Create possible extra actual for constrained case. Usually, the + -- extra actual is of the form actual'constrained, but since this + -- attribute is only available for unconstrained records, TRUE is + -- expanded if the type of the formal happens to be constrained (for + -- instance when this procedure is inherited from an unconstrained + -- record to a constrained one) or if the actual has no discriminant + -- (its type is constrained). An exception to this is the case of a + -- private type without discriminants. In this case we pass FALSE + -- because the object has underlying discriminants with defaults. + + if Present (Extra_Constrained (Formal)) then + if Ekind (Etype (Prev)) in Private_Kind + and then not Has_Discriminants (Base_Type (Etype (Prev))) + then + Add_Extra_Actual ( + New_Occurrence_Of (Standard_False, Loc), + Extra_Constrained (Formal)); + + elsif Is_Constrained (Etype (Formal)) + or else not Has_Discriminants (Etype (Prev)) + then + Add_Extra_Actual ( + New_Occurrence_Of (Standard_True, Loc), + Extra_Constrained (Formal)); + + -- Do not produce extra actuals for Unchecked_Union parameters. + -- Jump directly to the end of the loop. + + elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then + goto Skip_Extra_Actual_Generation; + + else + -- If the actual is a type conversion, then the constrained + -- test applies to the actual, not the target type. + + declare + Act_Prev : Node_Id; + + begin + -- Test for unchecked conversions as well, which can occur + -- as out parameter actuals on calls to stream procedures. + + Act_Prev := Prev; + while Nkind_In (Act_Prev, N_Type_Conversion, + N_Unchecked_Type_Conversion) + loop + Act_Prev := Expression (Act_Prev); + end loop; + + -- If the expression is a conversion of a dereference, + -- this is internally generated code that manipulates + -- addresses, e.g. when building interface tables. No + -- check should occur in this case, and the discriminated + -- object is not directly a hand. + + if not Comes_From_Source (Actual) + and then Nkind (Actual) = N_Unchecked_Type_Conversion + and then Nkind (Act_Prev) = N_Explicit_Dereference + then + Add_Extra_Actual + (New_Occurrence_Of (Standard_False, Loc), + Extra_Constrained (Formal)); + + else + Add_Extra_Actual + (Make_Attribute_Reference (Sloc (Prev), + Prefix => + Duplicate_Subexpr_No_Checks + (Act_Prev, Name_Req => True), + Attribute_Name => Name_Constrained), + Extra_Constrained (Formal)); + end if; + end; + end if; + end if; + + -- Create possible extra actual for accessibility level + + if Present (Extra_Accessibility (Formal)) then + + -- Ada 2005 (AI-252): If the actual was rewritten as an Access + -- attribute, then the original actual may be an aliased object + -- occurring as the prefix in a call using "Object.Operation" + -- notation. In that case we must pass the level of the object, + -- so Prev_Orig is reset to Prev and the attribute will be + -- processed by the code for Access attributes further below. + + if Prev_Orig /= Prev + and then Nkind (Prev) = N_Attribute_Reference + and then + Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access + and then Is_Aliased_View (Prev_Orig) + then + Prev_Orig := Prev; + end if; + + -- Ada 2005 (AI-251): Thunks must propagate the extra actuals + -- of accessibility levels. + + if Ekind (Current_Scope) in Subprogram_Kind + and then Is_Thunk (Current_Scope) + then + declare + Parm_Ent : Entity_Id; + + begin + if Is_Controlling_Actual (Actual) then + + -- Find the corresponding actual of the thunk + + Parm_Ent := First_Entity (Current_Scope); + for J in 2 .. Param_Count loop + Next_Entity (Parm_Ent); + end loop; + + else pragma Assert (Is_Entity_Name (Actual)); + Parm_Ent := Entity (Actual); + end if; + + Add_Extra_Actual + (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc), + Extra_Accessibility (Formal)); + end; + + elsif Is_Entity_Name (Prev_Orig) then + + -- When passing an access parameter, or a renaming of an access + -- parameter, as the actual to another access parameter we need + -- to pass along the actual's own access level parameter. This + -- is done if we are within the scope of the formal access + -- parameter (if this is an inlined body the extra formal is + -- irrelevant). + + if (Is_Formal (Entity (Prev_Orig)) + or else + (Present (Renamed_Object (Entity (Prev_Orig))) + and then + Is_Entity_Name (Renamed_Object (Entity (Prev_Orig))) + and then + Is_Formal + (Entity (Renamed_Object (Entity (Prev_Orig)))))) + and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type + and then In_Open_Scopes (Scope (Entity (Prev_Orig))) + then + declare + Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig); + + begin + pragma Assert (Present (Parm_Ent)); + + if Present (Extra_Accessibility (Parm_Ent)) then + Add_Extra_Actual + (New_Occurrence_Of + (Extra_Accessibility (Parm_Ent), Loc), + Extra_Accessibility (Formal)); + + -- If the actual access parameter does not have an + -- associated extra formal providing its scope level, + -- then treat the actual as having library-level + -- accessibility. + + else + Add_Extra_Actual + (Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + Extra_Accessibility (Formal)); + end if; + end; + + -- The actual is a normal access value, so just pass the level + -- of the actual's access type. + + else + Add_Extra_Actual + (Make_Integer_Literal (Loc, + Intval => Type_Access_Level (Etype (Prev_Orig))), + Extra_Accessibility (Formal)); + end if; + + -- All cases other than thunks + + else + case Nkind (Prev_Orig) is + + when N_Attribute_Reference => + case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is + + -- For X'Access, pass on the level of the prefix X + + when Attribute_Access => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => + Object_Access_Level (Prefix (Prev_Orig))), + Extra_Accessibility (Formal)); + + -- Treat the unchecked attributes as library-level + + when Attribute_Unchecked_Access | + Attribute_Unrestricted_Access => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + Extra_Accessibility (Formal)); + + -- No other cases of attributes returning access + -- values that can be passed to access parameters + + when others => + raise Program_Error; + + end case; + + -- For allocators we pass the level of the execution of + -- the called subprogram, which is one greater than the + -- current scope level. + + when N_Allocator => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Scope_Depth (Current_Scope) + 1), + Extra_Accessibility (Formal)); + + -- For other cases we simply pass the level of the + -- actual's access type. + + when others => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Type_Access_Level (Etype (Prev_Orig))), + Extra_Accessibility (Formal)); + + end case; + end if; + end if; + + -- Perform the check of 4.6(49) that prevents a null value from being + -- passed as an actual to an access parameter. Note that the check is + -- elided in the common cases of passing an access attribute or + -- access parameter as an actual. Also, we currently don't enforce + -- this check for expander-generated actuals and when -gnatdj is set. + + if Ada_Version >= Ada_05 then + + -- Ada 2005 (AI-231): Check null-excluding access types + + if Is_Access_Type (Etype (Formal)) + and then Can_Never_Be_Null (Etype (Formal)) + and then Nkind (Prev) /= N_Raise_Constraint_Error + and then (Known_Null (Prev) + or else not Can_Never_Be_Null (Etype (Prev))) + then + Install_Null_Excluding_Check (Prev); + end if; + + -- Ada_Version < Ada_05 + + else + if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type + or else Access_Checks_Suppressed (Subp) + then + null; + + elsif Debug_Flag_J then + null; + + elsif not Comes_From_Source (Prev) then + null; + + elsif Is_Entity_Name (Prev) + and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type + then + null; + + elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then + null; + + -- Suppress null checks when passing to access parameters of Java + -- and CIL subprograms. (Should this be done for other foreign + -- conventions as well ???) + + elsif Convention (Subp) = Convention_Java + or else Convention (Subp) = Convention_CIL + then + null; + + else + Install_Null_Excluding_Check (Prev); + end if; + end if; + + -- Perform appropriate validity checks on parameters that + -- are entities. + + if Validity_Checks_On then + if (Ekind (Formal) = E_In_Parameter + and then Validity_Check_In_Params) + or else + (Ekind (Formal) = E_In_Out_Parameter + and then Validity_Check_In_Out_Params) + then + -- If the actual is an indexed component of a packed type (or + -- is an indexed or selected component whose prefix recursively + -- meets this condition), it has not been expanded yet. It will + -- be copied in the validity code that follows, and has to be + -- expanded appropriately, so reanalyze it. + + -- What we do is just to unset analyzed bits on prefixes till + -- we reach something that does not have a prefix. + + declare + Nod : Node_Id; + + begin + Nod := Actual; + while Nkind_In (Nod, N_Indexed_Component, + N_Selected_Component) + loop + Set_Analyzed (Nod, False); + Nod := Prefix (Nod); + end loop; + end; + + Ensure_Valid (Actual); + end if; + end if; + + -- For IN OUT and OUT parameters, ensure that subscripts are valid + -- since this is a left side reference. We only do this for calls + -- from the source program since we assume that compiler generated + -- calls explicitly generate any required checks. We also need it + -- only if we are doing standard validity checks, since clearly it + -- is not needed if validity checks are off, and in subscript + -- validity checking mode, all indexed components are checked with + -- a call directly from Expand_N_Indexed_Component. + + if Comes_From_Source (N) + and then Ekind (Formal) /= E_In_Parameter + and then Validity_Checks_On + and then Validity_Check_Default + and then not Validity_Check_Subscripts + then + Check_Valid_Lvalue_Subscripts (Actual); + end if; + + -- Mark any scalar OUT parameter that is a simple variable as no + -- longer known to be valid (unless the type is always valid). This + -- reflects the fact that if an OUT parameter is never set in a + -- procedure, then it can become invalid on the procedure return. + + if Ekind (Formal) = E_Out_Parameter + and then Is_Entity_Name (Actual) + and then Ekind (Entity (Actual)) = E_Variable + and then not Is_Known_Valid (Etype (Actual)) + then + Set_Is_Known_Valid (Entity (Actual), False); + end if; + + -- For an OUT or IN OUT parameter, if the actual is an entity, then + -- clear current values, since they can be clobbered. We are probably + -- doing this in more places than we need to, but better safe than + -- sorry when it comes to retaining bad current values! + + if Ekind (Formal) /= E_In_Parameter + and then Is_Entity_Name (Actual) + and then Present (Entity (Actual)) + then + declare + Ent : constant Entity_Id := Entity (Actual); + Sav : Node_Id; + + begin + -- For an OUT or IN OUT parameter that is an assignable entity, + -- we do not want to clobber the Last_Assignment field, since + -- if it is set, it was precisely because it is indeed an OUT + -- or IN OUT parameter! + + if (Ekind (Formal) = E_Out_Parameter + or else + Ekind (Formal) = E_In_Out_Parameter) + and then Is_Assignable (Ent) + then + Sav := Last_Assignment (Ent); + Kill_Current_Values (Ent); + Set_Last_Assignment (Ent, Sav); + + -- For all other cases, just kill the current values + + else + Kill_Current_Values (Ent); + end if; + end; + end if; + + -- If the formal is class wide and the actual is an aggregate, force + -- evaluation so that the back end who does not know about class-wide + -- type, does not generate a temporary of the wrong size. + + if not Is_Class_Wide_Type (Etype (Formal)) then + null; + + elsif Nkind (Actual) = N_Aggregate + or else (Nkind (Actual) = N_Qualified_Expression + and then Nkind (Expression (Actual)) = N_Aggregate) + then + Force_Evaluation (Actual); + end if; + + -- In a remote call, if the formal is of a class-wide type, check + -- that the actual meets the requirements described in E.4(18). + + if Remote and then Is_Class_Wide_Type (Etype (Formal)) then + Insert_Action (Actual, + Make_Transportable_Check (Loc, + Duplicate_Subexpr_Move_Checks (Actual))); + end if; + + -- This label is required when skipping extra actual generation for + -- Unchecked_Union parameters. + + <<Skip_Extra_Actual_Generation>> + + Param_Count := Param_Count + 1; + Next_Actual (Actual); + Next_Formal (Formal); + end loop; + + -- If we are expanding a rhs of an assignment we need to check if tag + -- propagation is needed. You might expect this processing to be in + -- Analyze_Assignment but has to be done earlier (bottom-up) because the + -- assignment might be transformed to a declaration for an unconstrained + -- value if the expression is classwide. + + if Nkind (N) = N_Function_Call + and then Is_Tag_Indeterminate (N) + and then Is_Entity_Name (Name (N)) + then + declare + Ass : Node_Id := Empty; + + begin + if Nkind (Parent (N)) = N_Assignment_Statement then + Ass := Parent (N); + + elsif Nkind (Parent (N)) = N_Qualified_Expression + and then Nkind (Parent (Parent (N))) = N_Assignment_Statement + then + Ass := Parent (Parent (N)); + + elsif Nkind (Parent (N)) = N_Explicit_Dereference + and then Nkind (Parent (Parent (N))) = N_Assignment_Statement + then + Ass := Parent (Parent (N)); + end if; + + if Present (Ass) + and then Is_Class_Wide_Type (Etype (Name (Ass))) + then + if Is_Access_Type (Etype (N)) then + if Designated_Type (Etype (N)) /= + Root_Type (Etype (Name (Ass))) + then + Error_Msg_NE + ("tag-indeterminate expression " + & " must have designated type& (RM 5.2 (6))", + N, Root_Type (Etype (Name (Ass)))); + else + Propagate_Tag (Name (Ass), N); + end if; + + elsif Etype (N) /= Root_Type (Etype (Name (Ass))) then + Error_Msg_NE + ("tag-indeterminate expression must have type&" + & "(RM 5.2 (6))", N, Root_Type (Etype (Name (Ass)))); + + else + Propagate_Tag (Name (Ass), N); + end if; + + -- The call will be rewritten as a dispatching call, and + -- expanded as such. + + return; + end if; + end; + end if; + + -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand + -- it to point to the correct secondary virtual table + + if Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement) + and then CW_Interface_Formals_Present + then + Expand_Interface_Actuals (N); + end if; + + -- Deals with Dispatch_Call if we still have a call, before expanding + -- extra actuals since this will be done on the re-analysis of the + -- dispatching call. Note that we do not try to shorten the actual + -- list for a dispatching call, it would not make sense to do so. + -- Expansion of dispatching calls is suppressed when VM_Target, because + -- the VM back-ends directly handle the generation of dispatching + -- calls and would have to undo any expansion to an indirect call. + + if Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement) + and then Present (Controlling_Argument (N)) + and then VM_Target = No_VM + then + Expand_Dispatching_Call (N); + + -- The following return is worrisome. Is it really OK to + -- skip all remaining processing in this procedure ??? + + return; + + -- Similarly, expand calls to RCI subprograms on which pragma + -- All_Calls_Remote applies. The rewriting will be reanalyzed + -- later. Do this only when the call comes from source since we do + -- not want such a rewritting to occur in expanded code. + + elsif Is_All_Remote_Call (N) then + Expand_All_Calls_Remote_Subprogram_Call (N); + + -- Similarly, do not add extra actuals for an entry call whose entity + -- is a protected procedure, or for an internal protected subprogram + -- call, because it will be rewritten as a protected subprogram call + -- and reanalyzed (see Expand_Protected_Subprogram_Call). + + elsif Is_Protected_Type (Scope (Subp)) + and then (Ekind (Subp) = E_Procedure + or else Ekind (Subp) = E_Function) + then + null; + + -- During that loop we gathered the extra actuals (the ones that + -- correspond to Extra_Formals), so now they can be appended. + + else + while Is_Non_Empty_List (Extra_Actuals) loop + Add_Actual_Parameter (Remove_Head (Extra_Actuals)); + end loop; + end if; + + -- At this point we have all the actuals, so this is the point at + -- which the various expansion activities for actuals is carried out. + + Expand_Actuals (N, Subp); + + -- If the subprogram is a renaming, or if it is inherited, replace it + -- in the call with the name of the actual subprogram being called. + -- If this is a dispatching call, the run-time decides what to call. + -- The Alias attribute does not apply to entries. + + if Nkind (N) /= N_Entry_Call_Statement + and then No (Controlling_Argument (N)) + and then Present (Parent_Subp) + then + if Present (Inherited_From_Formal (Subp)) then + Parent_Subp := Inherited_From_Formal (Subp); + else + while Present (Alias (Parent_Subp)) loop + Parent_Subp := Alias (Parent_Subp); + end loop; + end if; + + -- The below setting of Entity is suspect, see F109-018 discussion??? + + Set_Entity (Name (N), Parent_Subp); + + if Is_Abstract_Subprogram (Parent_Subp) + and then not In_Instance + then + Error_Msg_NE + ("cannot call abstract subprogram &!", Name (N), Parent_Subp); + end if; + + -- Add an explicit conversion for parameter of the derived type. + -- This is only done for scalar and access in-parameters. Others + -- have been expanded in expand_actuals. + + Formal := First_Formal (Subp); + Parent_Formal := First_Formal (Parent_Subp); + Actual := First_Actual (N); + + -- It is not clear that conversion is needed for intrinsic + -- subprograms, but it certainly is for those that are user- + -- defined, and that can be inherited on derivation, namely + -- unchecked conversion and deallocation. + -- General case needs study ??? + + if not Is_Intrinsic_Subprogram (Parent_Subp) + or else Is_Generic_Instance (Parent_Subp) + then + while Present (Formal) loop + if Etype (Formal) /= Etype (Parent_Formal) + and then Is_Scalar_Type (Etype (Formal)) + and then Ekind (Formal) = E_In_Parameter + and then + not Subtypes_Statically_Match + (Etype (Parent_Formal), Etype (Actual)) + and then not Raises_Constraint_Error (Actual) + then + Rewrite (Actual, + OK_Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + Enable_Range_Check (Actual); + + elsif Is_Access_Type (Etype (Formal)) + and then Base_Type (Etype (Parent_Formal)) /= + Base_Type (Etype (Actual)) + then + if Ekind (Formal) /= E_In_Parameter then + Rewrite (Actual, + Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + + elsif + Ekind (Etype (Parent_Formal)) = E_Anonymous_Access_Type + and then Designated_Type (Etype (Parent_Formal)) + /= + Designated_Type (Etype (Actual)) + and then not Is_Controlling_Formal (Formal) + then + -- This unchecked conversion is not necessary unless + -- inlining is enabled, because in that case the type + -- mismatch may become visible in the body about to be + -- inlined. + + Rewrite (Actual, + Unchecked_Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + end if; + end if; + + Next_Formal (Formal); + Next_Formal (Parent_Formal); + Next_Actual (Actual); + end loop; + end if; + + Orig_Subp := Subp; + Subp := Parent_Subp; + end if; + + -- Check for violation of No_Abort_Statements + + if Is_RTE (Subp, RE_Abort_Task) then + Check_Restriction (No_Abort_Statements, N); + + -- Check for violation of No_Dynamic_Attachment + + elsif RTU_Loaded (Ada_Interrupts) + and then (Is_RTE (Subp, RE_Is_Reserved) or else + Is_RTE (Subp, RE_Is_Attached) or else + Is_RTE (Subp, RE_Current_Handler) or else + Is_RTE (Subp, RE_Attach_Handler) or else + Is_RTE (Subp, RE_Exchange_Handler) or else + Is_RTE (Subp, RE_Detach_Handler) or else + Is_RTE (Subp, RE_Reference)) + then + Check_Restriction (No_Dynamic_Attachment, N); + end if; + + -- Deal with case where call is an explicit dereference + + if Nkind (Name (N)) = N_Explicit_Dereference then + + -- Handle case of access to protected subprogram type + + if Is_Access_Protected_Subprogram_Type + (Base_Type (Etype (Prefix (Name (N))))) + then + -- If this is a call through an access to protected operation, + -- the prefix has the form (object'address, operation'access). + -- Rewrite as a for other protected calls: the object is the + -- first parameter of the list of actuals. + + declare + Call : Node_Id; + Parm : List_Id; + Nam : Node_Id; + Obj : Node_Id; + Ptr : constant Node_Id := Prefix (Name (N)); + + T : constant Entity_Id := + Equivalent_Type (Base_Type (Etype (Ptr))); + + D_T : constant Entity_Id := + Designated_Type (Base_Type (Etype (Ptr))); + + begin + Obj := + Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => + New_Occurrence_Of (First_Entity (T), Loc)); + + Nam := + Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => + New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc)); + + Nam := + Make_Explicit_Dereference (Loc, + Prefix => Nam); + + if Present (Parameter_Associations (N)) then + Parm := Parameter_Associations (N); + else + Parm := New_List; + end if; + + Prepend (Obj, Parm); + + if Etype (D_T) = Standard_Void_Type then + Call := + Make_Procedure_Call_Statement (Loc, + Name => Nam, + Parameter_Associations => Parm); + else + Call := + Make_Function_Call (Loc, + Name => Nam, + Parameter_Associations => Parm); + end if; + + Set_First_Named_Actual (Call, First_Named_Actual (N)); + Set_Etype (Call, Etype (D_T)); + + -- We do not re-analyze the call to avoid infinite recursion. + -- We analyze separately the prefix and the object, and set + -- the checks on the prefix that would otherwise be emitted + -- when resolving a call. + + Rewrite (N, Call); + Analyze (Nam); + Apply_Access_Check (Nam); + Analyze (Obj); + return; + end; + end if; + end if; + + -- If this is a call to an intrinsic subprogram, then perform the + -- appropriate expansion to the corresponding tree node and we + -- are all done (since after that the call is gone!) + + -- In the case where the intrinsic is to be processed by the back end, + -- the call to Expand_Intrinsic_Call will do nothing, which is fine, + -- since the idea in this case is to pass the call unchanged. + -- If the intrinsic is an inherited unchecked conversion, and the + -- derived type is the target type of the conversion, we must retain + -- it as the return type of the expression. Otherwise the expansion + -- below, which uses the parent operation, will yield the wrong type. + + if Is_Intrinsic_Subprogram (Subp) then + Expand_Intrinsic_Call (N, Subp); + + if Nkind (N) = N_Unchecked_Type_Conversion + and then Parent_Subp /= Orig_Subp + and then Etype (Parent_Subp) /= Etype (Orig_Subp) + then + Set_Etype (N, Etype (Orig_Subp)); + end if; + + return; + end if; + + if Ekind (Subp) = E_Function + or else Ekind (Subp) = E_Procedure + then + if Is_Inlined (Subp) then + + Inlined_Subprogram : declare + Bod : Node_Id; + Must_Inline : Boolean := False; + Spec : constant Node_Id := Unit_Declaration_Node (Subp); + Scop : constant Entity_Id := Scope (Subp); + + function In_Unfrozen_Instance return Boolean; + -- If the subprogram comes from an instance in the same + -- unit, and the instance is not yet frozen, inlining might + -- trigger order-of-elaboration problems in gigi. + + -------------------------- + -- In_Unfrozen_Instance -- + -------------------------- + + function In_Unfrozen_Instance return Boolean is + S : Entity_Id; + + begin + S := Scop; + while Present (S) + and then S /= Standard_Standard + loop + if Is_Generic_Instance (S) + and then Present (Freeze_Node (S)) + and then not Analyzed (Freeze_Node (S)) + then + return True; + end if; + + S := Scope (S); + end loop; + + return False; + end In_Unfrozen_Instance; + + -- Start of processing for Inlined_Subprogram + + begin + -- Verify that the body to inline has already been seen, and + -- that if the body is in the current unit the inlining does + -- not occur earlier. This avoids order-of-elaboration problems + -- in the back end. + + -- This should be documented in sinfo/einfo ??? + + if No (Spec) + or else Nkind (Spec) /= N_Subprogram_Declaration + or else No (Body_To_Inline (Spec)) + then + Must_Inline := False; + + -- If this an inherited function that returns a private + -- type, do not inline if the full view is an unconstrained + -- array, because such calls cannot be inlined. + + elsif Present (Orig_Subp) + and then Is_Array_Type (Etype (Orig_Subp)) + and then not Is_Constrained (Etype (Orig_Subp)) + then + Must_Inline := False; + + elsif In_Unfrozen_Instance then + Must_Inline := False; + + else + Bod := Body_To_Inline (Spec); + + if (In_Extended_Main_Code_Unit (N) + or else In_Extended_Main_Code_Unit (Parent (N)) + or else Has_Pragma_Inline_Always (Subp)) + and then (not In_Same_Extended_Unit (Sloc (Bod), Loc) + or else + Earlier_In_Extended_Unit (Sloc (Bod), Loc)) + then + Must_Inline := True; + + -- If we are compiling a package body that is not the main + -- unit, it must be for inlining/instantiation purposes, + -- in which case we inline the call to insure that the same + -- temporaries are generated when compiling the body by + -- itself. Otherwise link errors can occur. + + -- If the function being called is itself in the main unit, + -- we cannot inline, because there is a risk of double + -- elaboration and/or circularity: the inlining can make + -- visible a private entity in the body of the main unit, + -- that gigi will see before its sees its proper definition. + + elsif not (In_Extended_Main_Code_Unit (N)) + and then In_Package_Body + then + Must_Inline := not In_Extended_Main_Source_Unit (Subp); + end if; + end if; + + if Must_Inline then + Expand_Inlined_Call (N, Subp, Orig_Subp); + + else + -- Let the back end handle it + + Add_Inlined_Body (Subp); + + if Front_End_Inlining + and then Nkind (Spec) = N_Subprogram_Declaration + and then (In_Extended_Main_Code_Unit (N)) + and then No (Body_To_Inline (Spec)) + and then not Has_Completion (Subp) + and then In_Same_Extended_Unit (Sloc (Spec), Loc) + then + Cannot_Inline + ("cannot inline& (body not seen yet)?", + N, Subp); + end if; + end if; + end Inlined_Subprogram; + end if; + end if; + + -- Check for a protected subprogram. This is either an intra-object + -- call, or a protected function call. Protected procedure calls are + -- rewritten as entry calls and handled accordingly. + + -- In Ada 2005, this may be an indirect call to an access parameter + -- that is an access_to_subprogram. In that case the anonymous type + -- has a scope that is a protected operation, but the call is a + -- regular one. + + Scop := Scope (Subp); + + if Nkind (N) /= N_Entry_Call_Statement + and then Is_Protected_Type (Scop) + and then Ekind (Subp) /= E_Subprogram_Type + then + -- If the call is an internal one, it is rewritten as a call to + -- to the corresponding unprotected subprogram. + + Expand_Protected_Subprogram_Call (N, Subp, Scop); + end if; + + -- Functions returning controlled objects need special attention + -- If the return type is limited the context is an initialization + -- and different processing applies. + + if Controlled_Type (Etype (Subp)) + and then not Is_Inherently_Limited_Type (Etype (Subp)) + and then not Is_Limited_Interface (Etype (Subp)) + then + Expand_Ctrl_Function_Call (N); + end if; + + -- Test for First_Optional_Parameter, and if so, truncate parameter + -- list if there are optional parameters at the trailing end. + -- Note we never delete procedures for call via a pointer. + + if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function) + and then Present (First_Optional_Parameter (Subp)) + then + declare + Last_Keep_Arg : Node_Id; + + begin + -- Last_Keep_Arg will hold the last actual that should be + -- retained. If it remains empty at the end, it means that + -- all parameters are optional. + + Last_Keep_Arg := Empty; + + -- Find first optional parameter, must be present since we + -- checked the validity of the parameter before setting it. + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + while Formal /= First_Optional_Parameter (Subp) loop + Last_Keep_Arg := Actual; + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- We have Formal and Actual pointing to the first potentially + -- droppable argument. We can drop all the trailing arguments + -- whose actual matches the default. Note that we know that all + -- remaining formals have defaults, because we checked that this + -- requirement was met before setting First_Optional_Parameter. + + -- We use Fully_Conformant_Expressions to check for identity + -- between formals and actuals, which may miss some cases, but + -- on the other hand, this is only an optimization (if we fail + -- to truncate a parameter it does not affect functionality). + -- So if the default is 3 and the actual is 1+2, we consider + -- them unequal, which hardly seems worrisome. + + while Present (Formal) loop + if not Fully_Conformant_Expressions + (Actual, Default_Value (Formal)) + then + Last_Keep_Arg := Actual; + end if; + + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- If no arguments, delete entire list, this is the easy case + + if No (Last_Keep_Arg) then + Set_Parameter_Associations (N, No_List); + Set_First_Named_Actual (N, Empty); + + -- Case where at the last retained argument is positional. This + -- is also an easy case, since the retained arguments are already + -- in the right form, and we don't need to worry about the order + -- of arguments that get eliminated. + + elsif Is_List_Member (Last_Keep_Arg) then + while Present (Next (Last_Keep_Arg)) loop + Discard_Node (Remove_Next (Last_Keep_Arg)); + end loop; + + Set_First_Named_Actual (N, Empty); + + -- This is the annoying case where the last retained argument + -- is a named parameter. Since the original arguments are not + -- in declaration order, we may have to delete some fairly + -- random collection of arguments. + + else + declare + Temp : Node_Id; + Passoc : Node_Id; + + begin + -- First step, remove all the named parameters from the + -- list (they are still chained using First_Named_Actual + -- and Next_Named_Actual, so we have not lost them!) + + Temp := First (Parameter_Associations (N)); + + -- Case of all parameters named, remove them all + + if Nkind (Temp) = N_Parameter_Association then + while Is_Non_Empty_List (Parameter_Associations (N)) loop + Temp := Remove_Head (Parameter_Associations (N)); + end loop; + + -- Case of mixed positional/named, remove named parameters + + else + while Nkind (Next (Temp)) /= N_Parameter_Association loop + Next (Temp); + end loop; + + while Present (Next (Temp)) loop + Remove (Next (Temp)); + end loop; + end if; + + -- Now we loop through the named parameters, till we get + -- to the last one to be retained, adding them to the list. + -- Note that the Next_Named_Actual list does not need to be + -- touched since we are only reordering them on the actual + -- parameter association list. + + Passoc := Parent (First_Named_Actual (N)); + loop + Temp := Relocate_Node (Passoc); + Append_To + (Parameter_Associations (N), Temp); + exit when + Last_Keep_Arg = Explicit_Actual_Parameter (Passoc); + Passoc := Parent (Next_Named_Actual (Passoc)); + end loop; + + Set_Next_Named_Actual (Temp, Empty); + + loop + Temp := Next_Named_Actual (Passoc); + exit when No (Temp); + Set_Next_Named_Actual + (Passoc, Next_Named_Actual (Parent (Temp))); + end loop; + end; + end if; + end; + end if; + + -- Special processing for Ada 2005 AI-329, which requires a call to + -- Raise_Exception to raise Constraint_Error if the Exception_Id is + -- null. Note that we never need to do this in GNAT mode, or if the + -- parameter to Raise_Exception is a use of Identity, since in these + -- cases we know that the parameter is never null. + + -- Note: We must check that the node has not been inlined. This is + -- required because under zfp the Raise_Exception subprogram has the + -- pragma inline_always (and hence the call has been expanded above + -- into a block containing the code of the subprogram). + + if Ada_Version >= Ada_05 + and then not GNAT_Mode + and then Is_RTE (Subp, RE_Raise_Exception) + and then Nkind (N) = N_Procedure_Call_Statement + and then (Nkind (First_Actual (N)) /= N_Attribute_Reference + or else Attribute_Name (First_Actual (N)) /= Name_Identity) + then + declare + RCE : constant Node_Id := + Make_Raise_Constraint_Error (Loc, + Reason => CE_Null_Exception_Id); + begin + Insert_After (N, RCE); + Analyze (RCE); + end; + end if; + end Expand_Call; + + -------------------------- + -- Expand_Inlined_Call -- + -------------------------- + + procedure Expand_Inlined_Call + (N : Node_Id; + Subp : Entity_Id; + Orig_Subp : Entity_Id) + is + Loc : constant Source_Ptr := Sloc (N); + Is_Predef : constant Boolean := + Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Subp))); + Orig_Bod : constant Node_Id := + Body_To_Inline (Unit_Declaration_Node (Subp)); + + Blk : Node_Id; + Bod : Node_Id; + Decl : Node_Id; + Decls : constant List_Id := New_List; + Exit_Lab : Entity_Id := Empty; + F : Entity_Id; + A : Node_Id; + Lab_Decl : Node_Id; + Lab_Id : Node_Id; + New_A : Node_Id; + Num_Ret : Int := 0; + Ret_Type : Entity_Id; + Targ : Node_Id; + Targ1 : Node_Id; + Temp : Entity_Id; + Temp_Typ : Entity_Id; + + Is_Unc : constant Boolean := + Is_Array_Type (Etype (Subp)) + and then not Is_Constrained (Etype (Subp)); + -- If the type returned by the function is unconstrained and the + -- call can be inlined, special processing is required. + + function Is_Null_Procedure return Boolean; + -- Predicate to recognize stubbed procedures and null procedures, for + -- which there is no need for the full inlining mechanism. + + procedure Make_Exit_Label; + -- Build declaration for exit label to be used in Return statements + + function Process_Formals (N : Node_Id) return Traverse_Result; + -- Replace occurrence of a formal with the corresponding actual, or + -- the thunk generated for it. + + function Process_Sloc (Nod : Node_Id) return Traverse_Result; + -- If the call being expanded is that of an internal subprogram, + -- set the sloc of the generated block to that of the call itself, + -- so that the expansion is skipped by the -next- command in gdb. + -- Same processing for a subprogram in a predefined file, e.g. + -- Ada.Tags. If Debug_Generated_Code is true, suppress this change + -- to simplify our own development. + + procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id); + -- If the function body is a single expression, replace call with + -- expression, else insert block appropriately. + + procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id); + -- If procedure body has no local variables, inline body without + -- creating block, otherwise rewrite call with block. + + function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean; + -- Determine whether a formal parameter is used only once in Orig_Bod + + ----------------------- + -- Is_Null_Procedure -- + ----------------------- + + function Is_Null_Procedure return Boolean is + Decl : constant Node_Id := Unit_Declaration_Node (Subp); + + begin + if Ekind (Subp) /= E_Procedure then + return False; + + elsif Nkind (Orig_Bod) /= N_Subprogram_Body then + return False; + + -- Check if this is an Ada 2005 null procedure + + elsif Nkind (Decl) = N_Subprogram_Declaration + and then Null_Present (Specification (Decl)) + then + return True; + + -- Check if the body contains only a null statement, followed by the + -- return statement added during expansion. + + else + declare + Stat : constant Node_Id := + First + (Statements (Handled_Statement_Sequence (Orig_Bod))); + + Stat2 : constant Node_Id := Next (Stat); + + begin + return + Nkind (Stat) = N_Null_Statement + and then + (No (Stat2) + or else + (Nkind (Stat2) = N_Simple_Return_Statement + and then No (Next (Stat2)))); + end; + end if; + end Is_Null_Procedure; + + --------------------- + -- Make_Exit_Label -- + --------------------- + + procedure Make_Exit_Label is + begin + -- Create exit label for subprogram if one does not exist yet + + if No (Exit_Lab) then + Lab_Id := + Make_Identifier (Loc, + Chars => New_Internal_Name ('L')); + Set_Entity (Lab_Id, + Make_Defining_Identifier (Loc, Chars (Lab_Id))); + Exit_Lab := Make_Label (Loc, Lab_Id); + + Lab_Decl := + Make_Implicit_Label_Declaration (Loc, + Defining_Identifier => Entity (Lab_Id), + Label_Construct => Exit_Lab); + end if; + end Make_Exit_Label; + + --------------------- + -- Process_Formals -- + --------------------- + + function Process_Formals (N : Node_Id) return Traverse_Result is + A : Entity_Id; + E : Entity_Id; + Ret : Node_Id; + + begin + if Is_Entity_Name (N) + and then Present (Entity (N)) + then + E := Entity (N); + + if Is_Formal (E) + and then Scope (E) = Subp + then + A := Renamed_Object (E); + + -- Rewrite the occurrence of the formal into an occurrence of + -- the actual. Also establish visibility on the proper view of + -- the actual's subtype for the body's context (if the actual's + -- subtype is private at the call point but its full view is + -- visible to the body, then the inlined tree here must be + -- analyzed with the full view). + + if Is_Entity_Name (A) then + Rewrite (N, New_Occurrence_Of (Entity (A), Loc)); + Check_Private_View (N); + + elsif Nkind (A) = N_Defining_Identifier then + Rewrite (N, New_Occurrence_Of (A, Loc)); + Check_Private_View (N); + + -- Numeric literal + + else + Rewrite (N, New_Copy (A)); + end if; + end if; + + return Skip; + + elsif Nkind (N) = N_Simple_Return_Statement then + if No (Expression (N)) then + Make_Exit_Label; + Rewrite (N, + Make_Goto_Statement (Loc, + Name => New_Copy (Lab_Id))); + + else + if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements + and then Nkind (Parent (Parent (N))) = N_Subprogram_Body + then + -- Function body is a single expression. No need for + -- exit label. + + null; + + else + Num_Ret := Num_Ret + 1; + Make_Exit_Label; + end if; + + -- Because of the presence of private types, the views of the + -- expression and the context may be different, so place an + -- unchecked conversion to the context type to avoid spurious + -- errors, eg. when the expression is a numeric literal and + -- the context is private. If the expression is an aggregate, + -- use a qualified expression, because an aggregate is not a + -- legal argument of a conversion. + + if Nkind_In (Expression (N), N_Aggregate, N_Null) then + Ret := + Make_Qualified_Expression (Sloc (N), + Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)), + Expression => Relocate_Node (Expression (N))); + else + Ret := + Unchecked_Convert_To + (Ret_Type, Relocate_Node (Expression (N))); + end if; + + if Nkind (Targ) = N_Defining_Identifier then + Rewrite (N, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Targ, Loc), + Expression => Ret)); + else + Rewrite (N, + Make_Assignment_Statement (Loc, + Name => New_Copy (Targ), + Expression => Ret)); + end if; + + Set_Assignment_OK (Name (N)); + + if Present (Exit_Lab) then + Insert_After (N, + Make_Goto_Statement (Loc, + Name => New_Copy (Lab_Id))); + end if; + end if; + + return OK; + + -- Remove pragma Unreferenced since it may refer to formals that + -- are not visible in the inlined body, and in any case we will + -- not be posting warnings on the inlined body so it is unneeded. + + elsif Nkind (N) = N_Pragma + and then Chars (N) = Name_Unreferenced + then + Rewrite (N, Make_Null_Statement (Sloc (N))); + return OK; + + else + return OK; + end if; + end Process_Formals; + + procedure Replace_Formals is new Traverse_Proc (Process_Formals); + + ------------------ + -- Process_Sloc -- + ------------------ + + function Process_Sloc (Nod : Node_Id) return Traverse_Result is + begin + if not Debug_Generated_Code then + Set_Sloc (Nod, Sloc (N)); + Set_Comes_From_Source (Nod, False); + end if; + + return OK; + end Process_Sloc; + + procedure Reset_Slocs is new Traverse_Proc (Process_Sloc); + + --------------------------- + -- Rewrite_Function_Call -- + --------------------------- + + procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is + HSS : constant Node_Id := Handled_Statement_Sequence (Blk); + Fst : constant Node_Id := First (Statements (HSS)); + + begin + -- Optimize simple case: function body is a single return statement, + -- which has been expanded into an assignment. + + if Is_Empty_List (Declarations (Blk)) + and then Nkind (Fst) = N_Assignment_Statement + and then No (Next (Fst)) + then + + -- The function call may have been rewritten as the temporary + -- that holds the result of the call, in which case remove the + -- now useless declaration. + + if Nkind (N) = N_Identifier + and then Nkind (Parent (Entity (N))) = N_Object_Declaration + then + Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc)); + end if; + + Rewrite (N, Expression (Fst)); + + elsif Nkind (N) = N_Identifier + and then Nkind (Parent (Entity (N))) = N_Object_Declaration + then + -- The block assigns the result of the call to the temporary + + Insert_After (Parent (Entity (N)), Blk); + + elsif Nkind (Parent (N)) = N_Assignment_Statement + and then + (Is_Entity_Name (Name (Parent (N))) + or else + (Nkind (Name (Parent (N))) = N_Explicit_Dereference + and then Is_Entity_Name (Prefix (Name (Parent (N)))))) + then + -- Replace assignment with the block + + declare + Original_Assignment : constant Node_Id := Parent (N); + + begin + -- Preserve the original assignment node to keep the complete + -- assignment subtree consistent enough for Analyze_Assignment + -- to proceed (specifically, the original Lhs node must still + -- have an assignment statement as its parent). + + -- We cannot rely on Original_Node to go back from the block + -- node to the assignment node, because the assignment might + -- already be a rewrite substitution. + + Discard_Node (Relocate_Node (Original_Assignment)); + Rewrite (Original_Assignment, Blk); + end; + + elsif Nkind (Parent (N)) = N_Object_Declaration then + Set_Expression (Parent (N), Empty); + Insert_After (Parent (N), Blk); + + elsif Is_Unc then + Insert_Before (Parent (N), Blk); + end if; + end Rewrite_Function_Call; + + ---------------------------- + -- Rewrite_Procedure_Call -- + ---------------------------- + + procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is + HSS : constant Node_Id := Handled_Statement_Sequence (Blk); + begin + -- If there is a transient scope for N, this will be the scope of the + -- actions for N, and the statements in Blk need to be within this + -- scope. For example, they need to have visibility on the constant + -- declarations created for the formals. + + -- If N needs no transient scope, and if there are no declarations in + -- the inlined body, we can do a little optimization and insert the + -- statements for the body directly after N, and rewrite N to a + -- null statement, instead of rewriting N into a full-blown block + -- statement. + + if not Scope_Is_Transient + and then Is_Empty_List (Declarations (Blk)) + then + Insert_List_After (N, Statements (HSS)); + Rewrite (N, Make_Null_Statement (Loc)); + else + Rewrite (N, Blk); + end if; + end Rewrite_Procedure_Call; + + ------------------------- + -- Formal_Is_Used_Once -- + ------------------------- + + function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is + Use_Counter : Int := 0; + + function Count_Uses (N : Node_Id) return Traverse_Result; + -- Traverse the tree and count the uses of the formal parameter. + -- In this case, for optimization purposes, we do not need to + -- continue the traversal once more than one use is encountered. + + ---------------- + -- Count_Uses -- + ---------------- + + function Count_Uses (N : Node_Id) return Traverse_Result is + begin + -- The original node is an identifier + + if Nkind (N) = N_Identifier + and then Present (Entity (N)) + + -- Original node's entity points to the one in the copied body + + and then Nkind (Entity (N)) = N_Identifier + and then Present (Entity (Entity (N))) + + -- The entity of the copied node is the formal parameter + + and then Entity (Entity (N)) = Formal + then + Use_Counter := Use_Counter + 1; + + if Use_Counter > 1 then + + -- Denote more than one use and abandon the traversal + + Use_Counter := 2; + return Abandon; + + end if; + end if; + + return OK; + end Count_Uses; + + procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses); + + -- Start of processing for Formal_Is_Used_Once + + begin + Count_Formal_Uses (Orig_Bod); + return Use_Counter = 1; + end Formal_Is_Used_Once; + + -- Start of processing for Expand_Inlined_Call + + begin + -- Check for special case of To_Address call, and if so, just do an + -- unchecked conversion instead of expanding the call. Not only is this + -- more efficient, but it also avoids problem with order of elaboration + -- when address clauses are inlined (address expression elaborated at + -- wrong point). + + if Subp = RTE (RE_To_Address) then + Rewrite (N, + Unchecked_Convert_To + (RTE (RE_Address), + Relocate_Node (First_Actual (N)))); + return; + + elsif Is_Null_Procedure then + Rewrite (N, Make_Null_Statement (Loc)); + return; + end if; + + -- Check for an illegal attempt to inline a recursive procedure. If the + -- subprogram has parameters this is detected when trying to supply a + -- binding for parameters that already have one. For parameterless + -- subprograms this must be done explicitly. + + if In_Open_Scopes (Subp) then + Error_Msg_N ("call to recursive subprogram cannot be inlined?", N); + Set_Is_Inlined (Subp, False); + return; + end if; + + if Nkind (Orig_Bod) = N_Defining_Identifier + or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol + then + -- Subprogram is a renaming_as_body. Calls appearing after the + -- renaming can be replaced with calls to the renamed entity + -- directly, because the subprograms are subtype conformant. If + -- the renamed subprogram is an inherited operation, we must redo + -- the expansion because implicit conversions may be needed. + + Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc)); + + if Present (Alias (Orig_Bod)) then + Expand_Call (N); + end if; + + return; + end if; + + -- Use generic machinery to copy body of inlined subprogram, as if it + -- were an instantiation, resetting source locations appropriately, so + -- that nested inlined calls appear in the main unit. + + Save_Env (Subp, Empty); + Set_Copied_Sloc_For_Inlined_Body (N, Defining_Entity (Orig_Bod)); + + Bod := Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True); + Blk := + Make_Block_Statement (Loc, + Declarations => Declarations (Bod), + Handled_Statement_Sequence => Handled_Statement_Sequence (Bod)); + + if No (Declarations (Bod)) then + Set_Declarations (Blk, New_List); + end if; + + -- For the unconstrained case, capture the name of the local + -- variable that holds the result. This must be the first declaration + -- in the block, because its bounds cannot depend on local variables. + -- Otherwise there is no way to declare the result outside of the + -- block. Needless to say, in general the bounds will depend on the + -- actuals in the call. + + if Is_Unc then + Targ1 := Defining_Identifier (First (Declarations (Blk))); + end if; + + -- If this is a derived function, establish the proper return type + + if Present (Orig_Subp) + and then Orig_Subp /= Subp + then + Ret_Type := Etype (Orig_Subp); + else + Ret_Type := Etype (Subp); + end if; + + -- Create temporaries for the actuals that are expressions, or that + -- are scalars and require copying to preserve semantics. + + F := First_Formal (Subp); + A := First_Actual (N); + while Present (F) loop + if Present (Renamed_Object (F)) then + Error_Msg_N ("cannot inline call to recursive subprogram", N); + return; + end if; + + -- If the argument may be a controlling argument in a call within + -- the inlined body, we must preserve its classwide nature to insure + -- that dynamic dispatching take place subsequently. If the formal + -- has a constraint it must be preserved to retain the semantics of + -- the body. + + if Is_Class_Wide_Type (Etype (F)) + or else (Is_Access_Type (Etype (F)) + and then + Is_Class_Wide_Type (Designated_Type (Etype (F)))) + then + Temp_Typ := Etype (F); + + elsif Base_Type (Etype (F)) = Base_Type (Etype (A)) + and then Etype (F) /= Base_Type (Etype (F)) + then + Temp_Typ := Etype (F); + + else + Temp_Typ := Etype (A); + end if; + + -- If the actual is a simple name or a literal, no need to + -- create a temporary, object can be used directly. + + -- If the actual is a literal and the formal has its address taken, + -- we cannot pass the literal itself as an argument, so its value + -- must be captured in a temporary. + + if (Is_Entity_Name (A) + and then + (not Is_Scalar_Type (Etype (A)) + or else Ekind (Entity (A)) = E_Enumeration_Literal)) + + -- When the actual is an identifier and the corresponding formal + -- is used only once in the original body, the formal can be + -- substituted directly with the actual parameter. + + or else (Nkind (A) = N_Identifier + and then Formal_Is_Used_Once (F)) + + or else + (Nkind_In (A, N_Real_Literal, + N_Integer_Literal, + N_Character_Literal) + and then not Address_Taken (F)) + then + if Etype (F) /= Etype (A) then + Set_Renamed_Object + (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A))); + else + Set_Renamed_Object (F, A); + end if; + + else + Temp := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('C')); + + -- If the actual for an in/in-out parameter is a view conversion, + -- make it into an unchecked conversion, given that an untagged + -- type conversion is not a proper object for a renaming. + + -- In-out conversions that involve real conversions have already + -- been transformed in Expand_Actuals. + + if Nkind (A) = N_Type_Conversion + and then Ekind (F) /= E_In_Parameter + then + New_A := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Etype (F), Loc), + Expression => Relocate_Node (Expression (A))); + + elsif Etype (F) /= Etype (A) then + New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A)); + Temp_Typ := Etype (F); + + else + New_A := Relocate_Node (A); + end if; + + Set_Sloc (New_A, Sloc (N)); + + -- If the actual has a by-reference type, it cannot be copied, so + -- its value is captured in a renaming declaration. Otherwise + -- declare a local constant initialized with the actual. + + if Ekind (F) = E_In_Parameter + and then not Is_Limited_Type (Etype (A)) + and then not Is_Tagged_Type (Etype (A)) + then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Temp_Typ, Loc), + Expression => New_A); + else + Decl := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Temp, + Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc), + Name => New_A); + end if; + + Append (Decl, Decls); + Set_Renamed_Object (F, Temp); + end if; + + Next_Formal (F); + Next_Actual (A); + end loop; + + -- Establish target of function call. If context is not assignment or + -- declaration, create a temporary as a target. The declaration for + -- the temporary may be subsequently optimized away if the body is a + -- single expression, or if the left-hand side of the assignment is + -- simple enough, i.e. an entity or an explicit dereference of one. + + if Ekind (Subp) = E_Function then + if Nkind (Parent (N)) = N_Assignment_Statement + and then Is_Entity_Name (Name (Parent (N))) + then + Targ := Name (Parent (N)); + + elsif Nkind (Parent (N)) = N_Assignment_Statement + and then Nkind (Name (Parent (N))) = N_Explicit_Dereference + and then Is_Entity_Name (Prefix (Name (Parent (N)))) + then + Targ := Name (Parent (N)); + + else + -- Replace call with temporary and create its declaration + + Temp := + Make_Defining_Identifier (Loc, New_Internal_Name ('C')); + Set_Is_Internal (Temp); + + -- For the unconstrained case. the generated temporary has the + -- same constrained declaration as the result variable. + -- It may eventually be possible to remove that temporary and + -- use the result variable directly. + + if Is_Unc then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => + New_Copy_Tree (Object_Definition (Parent (Targ1)))); + + Replace_Formals (Decl); + + else + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => + New_Occurrence_Of (Ret_Type, Loc)); + + Set_Etype (Temp, Ret_Type); + end if; + + Set_No_Initialization (Decl); + Append (Decl, Decls); + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + Targ := Temp; + end if; + end if; + + Insert_Actions (N, Decls); + + -- Traverse the tree and replace formals with actuals or their thunks. + -- Attach block to tree before analysis and rewriting. + + Replace_Formals (Blk); + Set_Parent (Blk, N); + + if not Comes_From_Source (Subp) + or else Is_Predef + then + Reset_Slocs (Blk); + end if; + + if Present (Exit_Lab) then + + -- If the body was a single expression, the single return statement + -- and the corresponding label are useless. + + if Num_Ret = 1 + and then + Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) = + N_Goto_Statement + then + Remove (Last (Statements (Handled_Statement_Sequence (Blk)))); + else + Append (Lab_Decl, (Declarations (Blk))); + Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk))); + end if; + end if; + + -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on + -- conflicting private views that Gigi would ignore. If this is + -- predefined unit, analyze with checks off, as is done in the non- + -- inlined run-time units. + + declare + I_Flag : constant Boolean := In_Inlined_Body; + + begin + In_Inlined_Body := True; + + if Is_Predef then + declare + Style : constant Boolean := Style_Check; + begin + Style_Check := False; + Analyze (Blk, Suppress => All_Checks); + Style_Check := Style; + end; + + else + Analyze (Blk); + end if; + + In_Inlined_Body := I_Flag; + end; + + if Ekind (Subp) = E_Procedure then + Rewrite_Procedure_Call (N, Blk); + else + Rewrite_Function_Call (N, Blk); + + -- For the unconstrained case, the replacement of the call has been + -- made prior to the complete analysis of the generated declarations. + -- Propagate the proper type now. + + if Is_Unc then + if Nkind (N) = N_Identifier then + Set_Etype (N, Etype (Entity (N))); + else + Set_Etype (N, Etype (Targ1)); + end if; + end if; + end if; + + Restore_Env; + + -- Cleanup mapping between formals and actuals for other expansions + + F := First_Formal (Subp); + while Present (F) loop + Set_Renamed_Object (F, Empty); + Next_Formal (F); + end loop; + end Expand_Inlined_Call; + + ---------------------------- + -- Expand_N_Function_Call -- + ---------------------------- + + procedure Expand_N_Function_Call (N : Node_Id) is + begin + Expand_Call (N); + end Expand_N_Function_Call; + + --------------------------------------- + -- Expand_N_Procedure_Call_Statement -- + --------------------------------------- + + procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is + begin + Expand_Call (N); + end Expand_N_Procedure_Call_Statement; + + ------------------------------ + -- Expand_N_Subprogram_Body -- + ------------------------------ + + -- Add poll call if ATC polling is enabled, unless the body will be + -- inlined by the back-end. + + -- Add dummy push/pop label nodes at start and end to clear any local + -- exception indications if local-exception-to-goto optimization active. + + -- Add return statement if last statement in body is not a return statement + -- (this makes things easier on Gigi which does not want to have to handle + -- a missing return). + + -- Add call to Activate_Tasks if body is a task activator + + -- Deal with possible detection of infinite recursion + + -- Eliminate body completely if convention stubbed + + -- Encode entity names within body, since we will not need to reference + -- these entities any longer in the front end. + + -- Initialize scalar out parameters if Initialize/Normalize_Scalars + + -- Reset Pure indication if any parameter has root type System.Address + + -- Wrap thread body + + procedure Expand_N_Subprogram_Body (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + H : constant Node_Id := Handled_Statement_Sequence (N); + Body_Id : Entity_Id; + Spec_Id : Entity_Id; + Except_H : Node_Id; + Scop : Entity_Id; + Dec : Node_Id; + Next_Op : Node_Id; + L : List_Id; + + procedure Add_Return (S : List_Id); + -- Append a return statement to the statement sequence S if the last + -- statement is not already a return or a goto statement. Note that + -- the latter test is not critical, it does not matter if we add a + -- few extra returns, since they get eliminated anyway later on. + + ---------------- + -- Add_Return -- + ---------------- + + procedure Add_Return (S : List_Id) is + Last_Stm : Node_Id; + Loc : Source_Ptr; + + begin + -- Get last statement, ignoring any Pop_xxx_Label nodes, which are + -- not relevant in this context since they are not executable. + + Last_Stm := Last (S); + while Nkind (Last_Stm) in N_Pop_xxx_Label loop + Prev (Last_Stm); + end loop; + + -- Now insert return unless last statement is a transfer + + if not Is_Transfer (Last_Stm) then + + -- The source location for the return is the end label of the + -- procedure if present. Otherwise use the sloc of the last + -- statement in the list. If the list comes from a generated + -- exception handler and we are not debugging generated code, + -- all the statements within the handler are made invisible + -- to the debugger. + + if Nkind (Parent (S)) = N_Exception_Handler + and then not Comes_From_Source (Parent (S)) + then + Loc := Sloc (Last_Stm); + + elsif Present (End_Label (H)) then + Loc := Sloc (End_Label (H)); + + else + Loc := Sloc (Last_Stm); + end if; + + Append_To (S, Make_Simple_Return_Statement (Loc)); + end if; + end Add_Return; + + -- Start of processing for Expand_N_Subprogram_Body + + begin + -- Set L to either the list of declarations if present, or + -- to the list of statements if no declarations are present. + -- This is used to insert new stuff at the start. + + if Is_Non_Empty_List (Declarations (N)) then + L := Declarations (N); + else + L := Statements (H); + end if; + + -- If local-exception-to-goto optimization active, insert dummy push + -- statements at start, and dummy pop statements at end. + + if (Debug_Flag_Dot_G + or else Restriction_Active (No_Exception_Propagation)) + and then Is_Non_Empty_List (L) + then + declare + FS : constant Node_Id := First (L); + FL : constant Source_Ptr := Sloc (FS); + LS : Node_Id; + LL : Source_Ptr; + + begin + -- LS points to either last statement, if statements are present + -- or to the last declaration if there are no statements present. + -- It is the node after which the pop's are generated. + + if Is_Non_Empty_List (Statements (H)) then + LS := Last (Statements (H)); + else + LS := Last (L); + end if; + + LL := Sloc (LS); + + Insert_List_Before_And_Analyze (FS, New_List ( + Make_Push_Constraint_Error_Label (FL), + Make_Push_Program_Error_Label (FL), + Make_Push_Storage_Error_Label (FL))); + + Insert_List_After_And_Analyze (LS, New_List ( + Make_Pop_Constraint_Error_Label (LL), + Make_Pop_Program_Error_Label (LL), + Make_Pop_Storage_Error_Label (LL))); + end; + end if; + + -- Find entity for subprogram + + Body_Id := Defining_Entity (N); + + if Present (Corresponding_Spec (N)) then + Spec_Id := Corresponding_Spec (N); + else + Spec_Id := Body_Id; + end if; + + -- Need poll on entry to subprogram if polling enabled. We only do this + -- for non-empty subprograms, since it does not seem necessary to poll + -- for a dummy null subprogram. Do not add polling point if calls to + -- this subprogram will be inlined by the back-end, to avoid repeated + -- polling points in nested inlinings. + + if Is_Non_Empty_List (L) then + if Is_Inlined (Spec_Id) + and then Front_End_Inlining + and then Optimization_Level > 1 + then + null; + else + Generate_Poll_Call (First (L)); + end if; + end if; + + -- If this is a Pure function which has any parameters whose root + -- type is System.Address, reset the Pure indication, since it will + -- likely cause incorrect code to be generated as the parameter is + -- probably a pointer, and the fact that the same pointer is passed + -- does not mean that the same value is being referenced. + + -- Note that if the programmer gave an explicit Pure_Function pragma, + -- then we believe the programmer, and leave the subprogram Pure. + + -- This code should probably be at the freeze point, so that it + -- happens even on a -gnatc (or more importantly -gnatt) compile + -- so that the semantic tree has Is_Pure set properly ??? + + if Is_Pure (Spec_Id) + and then Is_Subprogram (Spec_Id) + and then not Has_Pragma_Pure_Function (Spec_Id) + then + declare + F : Entity_Id; + + begin + F := First_Formal (Spec_Id); + while Present (F) loop + if Is_Descendent_Of_Address (Etype (F)) then + Set_Is_Pure (Spec_Id, False); + + if Spec_Id /= Body_Id then + Set_Is_Pure (Body_Id, False); + end if; + + exit; + end if; + + Next_Formal (F); + end loop; + end; + end if; + + -- Initialize any scalar OUT args if Initialize/Normalize_Scalars + + if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then + declare + F : Entity_Id; + + begin + -- Loop through formals + + F := First_Formal (Spec_Id); + while Present (F) loop + if Is_Scalar_Type (Etype (F)) + and then Ekind (F) = E_Out_Parameter + then + -- Insert the initialization. We turn off validity checks + -- for this assignment, since we do not want any check on + -- the initial value itself (which may well be invalid). + + Insert_Before_And_Analyze (First (L), + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (F, Loc), + Expression => Get_Simple_Init_Val (Etype (F), Loc)), + Suppress => Validity_Check); + end if; + + Next_Formal (F); + end loop; + end; + end if; + + Scop := Scope (Spec_Id); + + -- Add discriminal renamings to protected subprograms. Install new + -- discriminals for expansion of the next subprogram of this protected + -- type, if any. + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + then + Add_Discriminal_Declarations + (Declarations (N), Scop, Name_uObject, Loc); + Add_Private_Declarations + (Declarations (N), Scop, Name_uObject, Loc); + + -- Associate privals and discriminals with the next protected + -- operation body to be expanded. These are used to expand references + -- to private data objects and discriminants, respectively. + + Next_Op := Next_Protected_Operation (N); + + if Present (Next_Op) then + Dec := Parent (Base_Type (Scop)); + Set_Privals (Dec, Next_Op, Loc); + Set_Discriminals (Dec); + end if; + end if; + + -- Clear out statement list for stubbed procedure + + if Present (Corresponding_Spec (N)) then + Set_Elaboration_Flag (N, Spec_Id); + + if Convention (Spec_Id) = Convention_Stubbed + or else Is_Eliminated (Spec_Id) + then + Set_Declarations (N, Empty_List); + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Make_Null_Statement (Loc)))); + return; + end if; + end if; + + -- Returns_By_Ref flag is normally set when the subprogram is frozen + -- but subprograms with no specs are not frozen. + + declare + Typ : constant Entity_Id := Etype (Spec_Id); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if not Acts_As_Spec (N) + and then Nkind (Parent (Parent (Spec_Id))) /= + N_Subprogram_Body_Stub + then + null; + + elsif Is_Inherently_Limited_Type (Typ) then + Set_Returns_By_Ref (Spec_Id); + + elsif Present (Utyp) and then CW_Or_Controlled_Type (Utyp) then + Set_Returns_By_Ref (Spec_Id); + end if; + end; + + -- For a procedure, we add a return for all possible syntactic ends + -- of the subprogram. Note that reanalysis is not necessary in this + -- case since it would require a lot of work and accomplish nothing. + + if Ekind (Spec_Id) = E_Procedure + or else Ekind (Spec_Id) = E_Generic_Procedure + then + Add_Return (Statements (H)); + + if Present (Exception_Handlers (H)) then + Except_H := First_Non_Pragma (Exception_Handlers (H)); + while Present (Except_H) loop + Add_Return (Statements (Except_H)); + Next_Non_Pragma (Except_H); + end loop; + end if; + + -- For a function, we must deal with the case where there is at least + -- one missing return. What we do is to wrap the entire body of the + -- function in a block: + + -- begin + -- ... + -- end; + + -- becomes + + -- begin + -- begin + -- ... + -- end; + + -- raise Program_Error; + -- end; + + -- This approach is necessary because the raise must be signalled + -- to the caller, not handled by any local handler (RM 6.4(11)). + + -- Note: we do not need to analyze the constructed sequence here, + -- since it has no handler, and an attempt to analyze the handled + -- statement sequence twice is risky in various ways (e.g. the + -- issue of expanding cleanup actions twice). + + elsif Has_Missing_Return (Spec_Id) then + declare + Hloc : constant Source_Ptr := Sloc (H); + Blok : constant Node_Id := + Make_Block_Statement (Hloc, + Handled_Statement_Sequence => H); + Rais : constant Node_Id := + Make_Raise_Program_Error (Hloc, + Reason => PE_Missing_Return); + + begin + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Hloc, + Statements => New_List (Blok, Rais))); + + Push_Scope (Spec_Id); + Analyze (Blok); + Analyze (Rais); + Pop_Scope; + end; + end if; + + -- If subprogram contains a parameterless recursive call, then we may + -- have an infinite recursion, so see if we can generate code to check + -- for this possibility if storage checks are not suppressed. + + if Ekind (Spec_Id) = E_Procedure + and then Has_Recursive_Call (Spec_Id) + and then not Storage_Checks_Suppressed (Spec_Id) + then + Detect_Infinite_Recursion (N, Spec_Id); + end if; + + -- Finally, if we are in Normalize_Scalars mode, then any scalar out + -- parameters must be initialized to the appropriate default value. + + if Ekind (Spec_Id) = E_Procedure and then Normalize_Scalars then + declare + Floc : Source_Ptr; + Formal : Entity_Id; + Stm : Node_Id; + + begin + Formal := First_Formal (Spec_Id); + while Present (Formal) loop + Floc := Sloc (Formal); + + if Ekind (Formal) = E_Out_Parameter + and then Is_Scalar_Type (Etype (Formal)) + then + Stm := + Make_Assignment_Statement (Floc, + Name => New_Occurrence_Of (Formal, Floc), + Expression => + Get_Simple_Init_Val (Etype (Formal), Floc)); + Prepend (Stm, Declarations (N)); + Analyze (Stm); + end if; + + Next_Formal (Formal); + end loop; + end; + end if; + + -- Set to encode entity names in package body before gigi is called + + Qualify_Entity_Names (N); + end Expand_N_Subprogram_Body; + + ----------------------------------- + -- Expand_N_Subprogram_Body_Stub -- + ----------------------------------- + + procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is + begin + if Present (Corresponding_Body (N)) then + Expand_N_Subprogram_Body ( + Unit_Declaration_Node (Corresponding_Body (N))); + end if; + end Expand_N_Subprogram_Body_Stub; + + ------------------------------------- + -- Expand_N_Subprogram_Declaration -- + ------------------------------------- + + -- If the declaration appears within a protected body, it is a private + -- operation of the protected type. We must create the corresponding + -- protected subprogram an associated formals. For a normal protected + -- operation, this is done when expanding the protected type declaration. + + -- If the declaration is for a null procedure, emit null body + + procedure Expand_N_Subprogram_Declaration (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Subp : constant Entity_Id := Defining_Entity (N); + Scop : constant Entity_Id := Scope (Subp); + Prot_Decl : Node_Id; + Prot_Bod : Node_Id; + Prot_Id : Entity_Id; + + begin + -- Deal with case of protected subprogram. Do not generate protected + -- operation if operation is flagged as eliminated. + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + and then Is_Protected_Type (Scop) + then + if No (Protected_Body_Subprogram (Subp)) + and then not Is_Eliminated (Subp) + then + Prot_Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Build_Protected_Sub_Specification + (N, Scop, Unprotected_Mode)); + + -- The protected subprogram is declared outside of the protected + -- body. Given that the body has frozen all entities so far, we + -- analyze the subprogram and perform freezing actions explicitly. + -- including the generation of an explicit freeze node, to ensure + -- that gigi has the proper order of elaboration. + -- If the body is a subunit, the insertion point is before the + -- stub in the parent. + + Prot_Bod := Parent (List_Containing (N)); + + if Nkind (Parent (Prot_Bod)) = N_Subunit then + Prot_Bod := Corresponding_Stub (Parent (Prot_Bod)); + end if; + + Insert_Before (Prot_Bod, Prot_Decl); + Prot_Id := Defining_Unit_Name (Specification (Prot_Decl)); + Set_Has_Delayed_Freeze (Prot_Id); + + Push_Scope (Scope (Scop)); + Analyze (Prot_Decl); + Insert_Actions (N, Freeze_Entity (Prot_Id, Loc)); + Set_Protected_Body_Subprogram (Subp, Prot_Id); + Pop_Scope; + end if; + + -- Ada 2005 (AI-348): Generation of the null body + + elsif Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + declare + Bod : constant Node_Id := + Make_Subprogram_Body (Loc, + Specification => + New_Copy_Tree (Specification (N)), + Declarations => New_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Make_Null_Statement (Loc)))); + begin + Set_Body_To_Inline (N, Bod); + Insert_After (N, Bod); + Analyze (Bod); + + -- Corresponding_Spec isn't being set by Analyze_Subprogram_Body, + -- evidently because Set_Has_Completion is called earlier for null + -- procedures in Analyze_Subprogram_Declaration, so we force its + -- setting here. If the setting of Has_Completion is not set + -- earlier, then it can result in missing body errors if other + -- errors were already reported (since expansion is turned off). + + -- Should creation of the empty body be moved to the analyzer??? + + Set_Corresponding_Spec (Bod, Defining_Entity (Specification (N))); + end; + end if; + end Expand_N_Subprogram_Declaration; + + --------------------------------------- + -- Expand_Protected_Object_Reference -- + --------------------------------------- + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (N); + Corr : Entity_Id; + Rec : Node_Id; + Param : Entity_Id; + Proc : Entity_Id; + + begin + Rec := + Make_Identifier (Loc, + Chars => Name_uObject); + Set_Etype (Rec, Corresponding_Record_Type (Scop)); + + -- Find enclosing protected operation, and retrieve its first parameter, + -- which denotes the enclosing protected object. If the enclosing + -- operation is an entry, we are immediately within the protected body, + -- and we can retrieve the object from the service entries procedure. A + -- barrier function has has the same signature as an entry. A barrier + -- function is compiled within the protected object, but unlike + -- protected operations its never needs locks, so that its protected + -- body subprogram points to itself. + + Proc := Current_Scope; + while Present (Proc) + and then Scope (Proc) /= Scop + loop + Proc := Scope (Proc); + end loop; + + Corr := Protected_Body_Subprogram (Proc); + + if No (Corr) then + + -- Previous error left expansion incomplete. + -- Nothing to do on this call. + + return Empty; + end if; + + Param := + Defining_Identifier + (First (Parameter_Specifications (Parent (Corr)))); + + if Is_Subprogram (Proc) + and then Proc /= Corr + then + -- Protected function or procedure + + Set_Entity (Rec, Param); + + -- Rec is a reference to an entity which will not be in scope when + -- the call is reanalyzed, and needs no further analysis. + + Set_Analyzed (Rec); + + else + -- Entry or barrier function for entry body. The first parameter of + -- the entry body procedure is pointer to the object. We create a + -- local variable of the proper type, duplicating what is done to + -- define _object later on. + + declare + Decls : List_Id; + Obj_Ptr : constant Entity_Id := Make_Defining_Identifier (Loc, + Chars => + New_Internal_Name ('T')); + + begin + Decls := New_List ( + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Obj_Ptr, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + Subtype_Indication => + New_Reference_To + (Corresponding_Record_Type (Scop), Loc)))); + + Insert_Actions (N, Decls); + Insert_Actions (N, Freeze_Entity (Obj_Ptr, Sloc (N))); + + Rec := + Make_Explicit_Dereference (Loc, + Unchecked_Convert_To (Obj_Ptr, + New_Occurrence_Of (Param, Loc))); + + -- Analyze new actual. Other actuals in calls are already analyzed + -- and the list of actuals is not reanalyzed after rewriting. + + Set_Parent (Rec, N); + Analyze (Rec); + end; + end if; + + return Rec; + end Expand_Protected_Object_Reference; + + -------------------------------------- + -- Expand_Protected_Subprogram_Call -- + -------------------------------------- + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id) + is + Rec : Node_Id; + + begin + -- If the protected object is not an enclosing scope, this is + -- an inter-object function call. Inter-object procedure + -- calls are expanded by Exp_Ch9.Build_Simple_Entry_Call. + -- The call is intra-object only if the subprogram being + -- called is in the protected body being compiled, and if the + -- protected object in the call is statically the enclosing type. + -- The object may be an component of some other data structure, + -- in which case this must be handled as an inter-object call. + + if not In_Open_Scopes (Scop) + or else not Is_Entity_Name (Name (N)) + then + if Nkind (Name (N)) = N_Selected_Component then + Rec := Prefix (Name (N)); + + else + pragma Assert (Nkind (Name (N)) = N_Indexed_Component); + Rec := Prefix (Prefix (Name (N))); + end if; + + Build_Protected_Subprogram_Call (N, + Name => New_Occurrence_Of (Subp, Sloc (N)), + Rec => Convert_Concurrent (Rec, Etype (Rec)), + External => True); + + else + Rec := Expand_Protected_Object_Reference (N, Scop); + + if No (Rec) then + return; + end if; + + Build_Protected_Subprogram_Call (N, + Name => Name (N), + Rec => Rec, + External => False); + + end if; + + Analyze (N); + + -- If it is a function call it can appear in elaboration code and + -- the called entity must be frozen here. + + if Ekind (Subp) = E_Function then + Freeze_Expression (Name (N)); + end if; + end Expand_Protected_Subprogram_Call; + + -------------------------------- + -- Is_Build_In_Place_Function -- + -------------------------------- + + function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is + begin + -- For now we test whether E denotes a function or access-to-function + -- type whose result subtype is inherently limited. Later this test may + -- be revised to allow composite nonlimited types. Functions with a + -- foreign convention or whose result type has a foreign convention + -- never qualify. + + if Ekind (E) = E_Function + or else Ekind (E) = E_Generic_Function + or else (Ekind (E) = E_Subprogram_Type + and then Etype (E) /= Standard_Void_Type) + then + -- Note: If you have Convention (C) on an inherently limited type, + -- you're on your own. That is, the C code will have to be carefully + -- written to know about the Ada conventions. + + if Has_Foreign_Convention (E) + or else Has_Foreign_Convention (Etype (E)) + then + return False; + + -- If the return type is a limited interface it has to be treated + -- as a return in place, even if the actual object is some non- + -- limited descendant. + + elsif Is_Limited_Interface (Etype (E)) then + return True; + + else + return Is_Inherently_Limited_Type (Etype (E)) + and then Ada_Version >= Ada_05 + and then not Debug_Flag_Dot_L; + end if; + + else + return False; + end if; + end Is_Build_In_Place_Function; + + ------------------------------------- + -- Is_Build_In_Place_Function_Call -- + ------------------------------------- + + function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is + Exp_Node : Node_Id := N; + Function_Id : Entity_Id; + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In + (Exp_Node, N_Qualified_Expression, N_Unchecked_Type_Conversion) + then + Exp_Node := Expression (N); + end if; + + if Nkind (Exp_Node) /= N_Function_Call then + return False; + + else + if Is_Entity_Name (Name (Exp_Node)) then + Function_Id := Entity (Name (Exp_Node)); + + elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Exp_Node)); + end if; + + return Is_Build_In_Place_Function (Function_Id); + end if; + end Is_Build_In_Place_Function_Call; + + --------------------------------------- + -- Is_Build_In_Place_Function_Return -- + --------------------------------------- + + function Is_Build_In_Place_Function_Return (N : Node_Id) return Boolean is + begin + if Nkind_In (N, N_Simple_Return_Statement, + N_Extended_Return_Statement) + then + return Is_Build_In_Place_Function + (Return_Applies_To (Return_Statement_Entity (N))); + else + return False; + end if; + end Is_Build_In_Place_Function_Return; + + ----------------------- + -- Freeze_Subprogram -- + ----------------------- + + procedure Freeze_Subprogram (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + + procedure Register_Predefined_DT_Entry (Prim : Entity_Id); + -- (Ada 2005): Register a predefined primitive in all the secondary + -- dispatch tables of its primitive type. + + ---------------------------------- + -- Register_Predefined_DT_Entry -- + ---------------------------------- + + procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is + Iface_DT_Ptr : Elmt_Id; + Tagged_Typ : Entity_Id; + Thunk_Id : Entity_Id; + Thunk_Code : Node_Id; + + begin + Tagged_Typ := Find_Dispatching_Type (Prim); + + if No (Access_Disp_Table (Tagged_Typ)) + or else not Has_Abstract_Interfaces (Tagged_Typ) + or else not RTE_Available (RE_Interface_Tag) + or else Restriction_Active (No_Dispatching_Calls) + then + return; + end if; + + -- Skip the first access-to-dispatch-table pointer since it leads + -- to the primary dispatch table. We are only concerned with the + -- secondary dispatch table pointers. Note that the access-to- + -- dispatch-table pointer corresponds to the first implemented + -- interface retrieved below. + + Iface_DT_Ptr := + Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ))); + + while Present (Iface_DT_Ptr) + and then Ekind (Node (Iface_DT_Ptr)) = E_Constant + loop + pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); + Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code); + + if Present (Thunk_Code) then + Insert_Actions_After (N, New_List ( + Thunk_Code, + + Build_Set_Predefined_Prim_Op_Address (Loc, + Tag_Node => New_Reference_To (Node (Iface_DT_Ptr), Loc), + Position => DT_Position (Prim), + Address_Node => + Make_Attribute_Reference (Loc, + Prefix => New_Reference_To (Thunk_Id, Loc), + Attribute_Name => Name_Address)), + + Build_Set_Predefined_Prim_Op_Address (Loc, + Tag_Node => New_Reference_To + (Node (Next_Elmt (Iface_DT_Ptr)), Loc), + Position => DT_Position (Prim), + Address_Node => + Make_Attribute_Reference (Loc, + Prefix => New_Reference_To (Prim, Loc), + Attribute_Name => Name_Address)))); + end if; + + Next_Elmt (Iface_DT_Ptr); + pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); + + Next_Elmt (Iface_DT_Ptr); + end loop; + end Register_Predefined_DT_Entry; + + -- Local variables + + Subp : constant Entity_Id := Entity (N); + + -- Start of processing for Freeze_Subprogram + + begin + -- We suppress the initialization of the dispatch table entry when + -- VM_Target because the dispatching mechanism is handled internally + -- by the VM. + + if Is_Dispatching_Operation (Subp) + and then not Is_Abstract_Subprogram (Subp) + and then Present (DTC_Entity (Subp)) + and then Present (Scope (DTC_Entity (Subp))) + and then VM_Target = No_VM + and then not Restriction_Active (No_Dispatching_Calls) + and then RTE_Available (RE_Tag) + then + declare + Typ : constant Entity_Id := Scope (DTC_Entity (Subp)); + + begin + -- Handle private overriden primitives + + if not Is_CPP_Class (Typ) then + Check_Overriding_Operation (Subp); + end if; + + -- We assume that imported CPP primitives correspond with objects + -- whose constructor is in the CPP side; therefore we don't need + -- to generate code to register them in the dispatch table. + + if Is_CPP_Class (Typ) then + null; + + -- Handle CPP primitives found in derivations of CPP_Class types. + -- These primitives must have been inherited from some parent, and + -- there is no need to register them in the dispatch table because + -- Build_Inherit_Prims takes care of the initialization of these + -- slots. + + elsif Is_Imported (Subp) + and then (Convention (Subp) = Convention_CPP + or else Convention (Subp) = Convention_C) + then + null; + + -- Generate code to register the primitive in non statically + -- allocated dispatch tables + + elsif not Static_Dispatch_Tables + or else not + Is_Library_Level_Tagged_Type (Scope (DTC_Entity (Subp))) + then + -- When a primitive is frozen, enter its name in its dispatch + -- table slot. + + if not Is_Interface (Typ) + or else Present (Abstract_Interface_Alias (Subp)) + then + if Is_Predefined_Dispatching_Operation (Subp) then + Register_Predefined_DT_Entry (Subp); + end if; + + Register_Primitive (Loc, + Prim => Subp, + Ins_Nod => N); + end if; + end if; + end; + end if; + + -- Mark functions that return by reference. Note that it cannot be part + -- of the normal semantic analysis of the spec since the underlying + -- returned type may not be known yet (for private types). + + declare + Typ : constant Entity_Id := Etype (Subp); + Utyp : constant Entity_Id := Underlying_Type (Typ); + begin + if Is_Inherently_Limited_Type (Typ) then + Set_Returns_By_Ref (Subp); + elsif Present (Utyp) and then CW_Or_Controlled_Type (Utyp) then + Set_Returns_By_Ref (Subp); + end if; + end; + end Freeze_Subprogram; + + ------------------------------------------- + -- Make_Build_In_Place_Call_In_Allocator -- + ------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Allocator + (Allocator : Node_Id; + Function_Call : Node_Id) + is + Loc : Source_Ptr; + Func_Call : Node_Id := Function_Call; + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + Acc_Type : constant Entity_Id := Etype (Allocator); + New_Allocator : Node_Id; + Return_Obj_Access : Entity_Id; + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In (Func_Call, + N_Qualified_Expression, + N_Unchecked_Type_Conversion) + then + Func_Call := Expression (Func_Call); + end if; + + -- If the call has already been processed to add build-in-place actuals + -- then return. This should not normally occur in an allocator context, + -- but we add the protection as a defensive measure. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + Loc := Sloc (Function_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Function_Id); + + -- When the result subtype is constrained, the return object must be + -- allocated on the caller side, and access to it is passed to the + -- function. + + -- Here and in related routines, we must examine the full view of the + -- type, because the view at the point of call may differ from that + -- that in the function body, and the expansion mechanism depends on + -- the characteristics of the full view. + + if Is_Constrained (Underlying_Type (Result_Subt)) then + + -- Replace the initialized allocator of form "new T'(Func (...))" + -- with an uninitialized allocator of form "new T", where T is the + -- result subtype of the called function. The call to the function + -- is handled separately further below. + + New_Allocator := + Make_Allocator (Loc, New_Reference_To (Result_Subt, Loc)); + + Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator)); + Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator)); + Set_No_Initialization (New_Allocator); + + Rewrite (Allocator, New_Allocator); + + -- Create a new access object and initialize it to the result of the + -- new uninitialized allocator. + + Return_Obj_Access := + Make_Defining_Identifier (Loc, New_Internal_Name ('R')); + Set_Etype (Return_Obj_Access, Acc_Type); + + Insert_Action (Allocator, + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Obj_Access, + Object_Definition => New_Reference_To (Acc_Type, Loc), + Expression => Relocate_Node (Allocator))); + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly + -- to functions with unconstrained result subtypes. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); + + -- Add an implicit actual to the function call that provides access + -- to the allocated object. An unchecked conversion to the (specific) + -- result subtype of the function is inserted to handle cases where + -- the access type of the allocator has a class-wide designated type. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, + Function_Id, + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Reference_To (Result_Subt, Loc), + Expression => + Make_Explicit_Dereference (Loc, + Prefix => New_Reference_To (Return_Obj_Access, Loc)))); + + -- When the result subtype is unconstrained, the function itself must + -- perform the allocation of the return object, so we pass parameters + -- indicating that. We don't yet handle the case where the allocation + -- must be done in a user-defined storage pool, which will require + -- passing another actual or two to provide allocation/deallocation + -- operations. ??? + + else + + -- Pass an allocation parameter indicating that the function should + -- allocate its result on the heap. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Global_Heap); + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); + + -- The caller does not provide the return object in this case, so we + -- have to pass null for the object access actual. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Return_Object => Empty); + end if; + + -- Finally, replace the allocator node with a reference to the result + -- of the function call itself (which will effectively be an access + -- to the object created by the allocator). + + Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call))); + Analyze_And_Resolve (Allocator, Acc_Type); + end Make_Build_In_Place_Call_In_Allocator; + + --------------------------------------------------- + -- Make_Build_In_Place_Call_In_Anonymous_Context -- + --------------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Anonymous_Context + (Function_Call : Node_Id) + is + Loc : Source_Ptr; + Func_Call : Node_Id := Function_Call; + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + Return_Obj_Id : Entity_Id; + Return_Obj_Decl : Entity_Id; + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In (Func_Call, N_Qualified_Expression, + N_Unchecked_Type_Conversion) + then + Func_Call := Expression (Func_Call); + end if; + + -- If the call has already been processed to add build-in-place actuals + -- then return. One place this can occur is for calls to build-in-place + -- functions that occur within a call to a protected operation, where + -- due to rewriting and expansion of the protected call there can be + -- more than one call to Expand_Actuals for the same set of actuals. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + Loc := Sloc (Function_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Function_Id); + + -- When the result subtype is constrained, an object of the subtype is + -- declared and an access value designating it is passed as an actual. + + if Is_Constrained (Underlying_Type (Result_Subt)) then + + -- Create a temporary object to hold the function result + + Return_Obj_Id := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('R')); + Set_Etype (Return_Obj_Id, Result_Subt); + + Return_Obj_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Obj_Id, + Aliased_Present => True, + Object_Definition => New_Reference_To (Result_Subt, Loc)); + + Set_No_Initialization (Return_Obj_Decl); + + Insert_Action (Func_Call, Return_Obj_Decl); + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly + -- to functions with unconstrained result subtypes. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type => Empty); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Add an implicit actual to the function call that provides access + -- to the caller's return object. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc)); + + -- When the result subtype is unconstrained, the function must allocate + -- the return object in the secondary stack, so appropriate implicit + -- parameters are added to the call to indicate that. A transient + -- scope is established to ensure eventual cleanup of the result. + + else + + -- Pass an allocation parameter indicating that the function should + -- allocate its result on the secondary stack. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type => Empty); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Pass a null value to the function since no return object is + -- available on the caller side. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Empty); + + Establish_Transient_Scope (Func_Call, Sec_Stack => True); + end if; + end Make_Build_In_Place_Call_In_Anonymous_Context; + + --------------------------------------------------- + -- Make_Build_In_Place_Call_In_Assignment -- + --------------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Assignment + (Assign : Node_Id; + Function_Call : Node_Id) + is + Lhs : constant Node_Id := Name (Assign); + Loc : Source_Ptr; + Func_Call : Node_Id := Function_Call; + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + Ref_Type : Entity_Id; + Ptr_Typ_Decl : Node_Id; + Def_Id : Entity_Id; + New_Expr : Node_Id; + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In (Func_Call, N_Qualified_Expression, + N_Unchecked_Type_Conversion) + then + Func_Call := Expression (Func_Call); + end if; + + -- If the call has already been processed to add build-in-place actuals + -- then return. This should not normally occur in an assignment context, + -- but we add the protection as a defensive measure. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + Loc := Sloc (Function_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Function_Id); + + -- When the result subtype is unconstrained, an additional actual must + -- be passed to indicate that the caller is providing the return object. + -- This parameter must also be passed when the called function has a + -- controlling result, because dispatching calls to the function needs + -- to be treated effectively the same as calls to class-wide functions. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type => Empty); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Add an implicit actual to the function call that provides access to + -- the caller's return object. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, + Function_Id, + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Reference_To (Result_Subt, Loc), + Expression => Relocate_Node (Lhs))); + + -- Create an access type designating the function's result subtype + + Ref_Type := + Make_Defining_Identifier (Loc, New_Internal_Name ('A')); + + Ptr_Typ_Decl := + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Ref_Type, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Subtype_Indication => + New_Reference_To (Result_Subt, Loc))); + + Insert_After_And_Analyze (Assign, Ptr_Typ_Decl); + + -- Finally, create an access object initialized to a reference to the + -- function call. + + Def_Id := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('R')); + Set_Etype (Def_Id, Ref_Type); + + New_Expr := + Make_Reference (Loc, + Prefix => Relocate_Node (Func_Call)); + + Insert_After_And_Analyze (Ptr_Typ_Decl, + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Object_Definition => New_Reference_To (Ref_Type, Loc), + Expression => New_Expr)); + + Rewrite (Assign, Make_Null_Statement (Loc)); + end Make_Build_In_Place_Call_In_Assignment; + + ---------------------------------------------------- + -- Make_Build_In_Place_Call_In_Object_Declaration -- + ---------------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Object_Declaration + (Object_Decl : Node_Id; + Function_Call : Node_Id) + is + Loc : Source_Ptr; + Obj_Def_Id : constant Entity_Id := + Defining_Identifier (Object_Decl); + + Func_Call : Node_Id := Function_Call; + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + Caller_Object : Node_Id; + Call_Deref : Node_Id; + Ref_Type : Entity_Id; + Ptr_Typ_Decl : Node_Id; + Def_Id : Entity_Id; + New_Expr : Node_Id; + Enclosing_Func : Entity_Id; + Pass_Caller_Acc : Boolean := False; + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In (Func_Call, N_Qualified_Expression, + N_Unchecked_Type_Conversion) + then + Func_Call := Expression (Func_Call); + end if; + + -- If the call has already been processed to add build-in-place actuals + -- then return. This should not normally occur in an object declaration, + -- but we add the protection as a defensive measure. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + Loc := Sloc (Function_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Function_Id); + + -- In the constrained case, add an implicit actual to the function call + -- that provides access to the declared object. An unchecked conversion + -- to the (specific) result type of the function is inserted to handle + -- the case where the object is declared with a class-wide type. + + if Is_Constrained (Underlying_Type (Result_Subt)) then + Caller_Object := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Reference_To (Result_Subt, Loc), + Expression => New_Reference_To (Obj_Def_Id, Loc)); + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly + -- to functions with unconstrained result subtypes. + + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + -- If the function's result subtype is unconstrained and the object is + -- a return object of an enclosing build-in-place function, then the + -- implicit build-in-place parameters of the enclosing function must be + -- passed along to the called function. + + elsif Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement then + Pass_Caller_Acc := True; + + Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id); + + -- If the enclosing function has a constrained result type, then + -- caller allocation will be used. + + if Is_Constrained (Etype (Enclosing_Func)) then + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + -- Otherwise, when the enclosing function has an unconstrained result + -- type, the BIP_Alloc_Form formal of the enclosing function must be + -- passed along to the callee. + + else + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, + Function_Id, + Alloc_Form_Exp => + New_Reference_To + (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form), + Loc)); + end if; + + -- Retrieve the BIPacc formal from the enclosing function and convert + -- it to the access type of the callee's BIP_Object_Access formal. + + Caller_Object := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => + New_Reference_To + (Etype + (Build_In_Place_Formal (Function_Id, BIP_Object_Access)), + Loc), + Expression => + New_Reference_To + (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access), + Loc)); + + -- In other unconstrained cases, pass an indication to do the allocation + -- on the secondary stack and set Caller_Object to Empty so that a null + -- value will be passed for the caller's object address. A transient + -- scope is established to ensure eventual cleanup of the result. + + else + Add_Alloc_Form_Actual_To_Build_In_Place_Call + (Func_Call, + Function_Id, + Alloc_Form => Secondary_Stack); + Caller_Object := Empty; + + Establish_Transient_Scope (Object_Decl, Sec_Stack => True); + end if; + + Add_Final_List_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type => Empty); + + if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement + and then Has_Task (Result_Subt) + then + Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id); + + -- Here we're passing along the master that was passed in to this + -- function. + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, + Master_Actual => + New_Reference_To + (Build_In_Place_Formal (Enclosing_Func, BIP_Master), Loc)); + + else + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + end if; + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc); + + -- Create an access type designating the function's result subtype + + Ref_Type := + Make_Defining_Identifier (Loc, New_Internal_Name ('A')); + + Ptr_Typ_Decl := + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Ref_Type, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Subtype_Indication => + New_Reference_To (Result_Subt, Loc))); + + -- The access type and its accompanying object must be inserted after + -- the object declaration in the constrained case, so that the function + -- call can be passed access to the object. In the unconstrained case, + -- the access type and object must be inserted before the object, since + -- the object declaration is rewritten to be a renaming of a dereference + -- of the access object. + + if Is_Constrained (Underlying_Type (Result_Subt)) then + Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl); + else + Insert_Before_And_Analyze (Object_Decl, Ptr_Typ_Decl); + end if; + + -- Finally, create an access object initialized to a reference to the + -- function call. + + Def_Id := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('R')); + Set_Etype (Def_Id, Ref_Type); + + New_Expr := + Make_Reference (Loc, + Prefix => Relocate_Node (Func_Call)); + + Insert_After_And_Analyze (Ptr_Typ_Decl, + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Object_Definition => New_Reference_To (Ref_Type, Loc), + Expression => New_Expr)); + + if Is_Constrained (Underlying_Type (Result_Subt)) then + Set_Expression (Object_Decl, Empty); + Set_No_Initialization (Object_Decl); + + -- In case of an unconstrained result subtype, rewrite the object + -- declaration as an object renaming where the renamed object is a + -- dereference of <function_Call>'reference: + -- + -- Obj : Subt renames <function_call>'Ref.all; + + else + Call_Deref := + Make_Explicit_Dereference (Loc, + Prefix => New_Reference_To (Def_Id, Loc)); + + Rewrite (Object_Decl, + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Make_Defining_Identifier (Loc, + New_Internal_Name ('D')), + Access_Definition => Empty, + Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), + Name => Call_Deref)); + + Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref); + + Analyze (Object_Decl); + + -- Replace the internal identifier of the renaming declaration's + -- entity with identifier of the original object entity. We also have + -- to exchange the entities containing their defining identifiers to + -- ensure the correct replacement of the object declaration by the + -- object renaming declaration to avoid homograph conflicts (since + -- the object declaration's defining identifier was already entered + -- in current scope). The Next_Entity links of the two entities also + -- have to be swapped since the entities are part of the return + -- scope's entity list and the list structure would otherwise be + -- corrupted. + + declare + Renaming_Def_Id : constant Entity_Id := + Defining_Identifier (Object_Decl); + Next_Entity_Temp : constant Entity_Id := + Next_Entity (Renaming_Def_Id); + begin + Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id)); + + -- Swap next entity links in preparation for exchanging entities + + Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id)); + Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp); + + Exchange_Entities (Renaming_Def_Id, Obj_Def_Id); + end; + end if; + + -- If the object entity has a class-wide Etype, then we need to change + -- it to the result subtype of the function call, because otherwise the + -- object will be class-wide without an explicit intialization and won't + -- be allocated properly by the back end. It seems unclean to make such + -- a revision to the type at this point, and we should try to improve + -- this treatment when build-in-place functions with class-wide results + -- are implemented. ??? + + if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then + Set_Etype (Defining_Identifier (Object_Decl), Result_Subt); + end if; + end Make_Build_In_Place_Call_In_Object_Declaration; + +end Exp_Ch6; |