1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Errout; use Errout;
31 with Elists; use Elists;
32 with Exp_Aggr; use Exp_Aggr;
33 with Exp_Atag; use Exp_Atag;
34 with Exp_Ch2; use Exp_Ch2;
35 with Exp_Ch3; use Exp_Ch3;
36 with Exp_Ch7; use Exp_Ch7;
37 with Exp_Ch9; use Exp_Ch9;
38 with Exp_Dbug; use Exp_Dbug;
39 with Exp_Disp; use Exp_Disp;
40 with Exp_Dist; use Exp_Dist;
41 with Exp_Intr; use Exp_Intr;
42 with Exp_Pakd; use Exp_Pakd;
43 with Exp_Tss; use Exp_Tss;
44 with Exp_Util; use Exp_Util;
45 with Exp_VFpt; use Exp_VFpt;
46 with Fname; use Fname;
47 with Freeze; use Freeze;
48 with Inline; use Inline;
50 with Namet; use Namet;
51 with Nlists; use Nlists;
52 with Nmake; use Nmake;
54 with Restrict; use Restrict;
55 with Rident; use Rident;
56 with Rtsfind; use Rtsfind;
58 with Sem_Aux; use Sem_Aux;
59 with Sem_Ch6; use Sem_Ch6;
60 with Sem_Ch8; use Sem_Ch8;
61 with Sem_Ch12; use Sem_Ch12;
62 with Sem_Ch13; use Sem_Ch13;
63 with Sem_Eval; use Sem_Eval;
64 with Sem_Disp; use Sem_Disp;
65 with Sem_Dist; use Sem_Dist;
66 with Sem_Mech; use Sem_Mech;
67 with Sem_Res; use Sem_Res;
68 with Sem_SCIL; use Sem_SCIL;
69 with Sem_Util; use Sem_Util;
70 with Sinfo; use Sinfo;
71 with Snames; use Snames;
72 with Stand; use Stand;
73 with Targparm; use Targparm;
74 with Tbuild; use Tbuild;
75 with Uintp; use Uintp;
76 with Validsw; use Validsw;
78 package body Exp_Ch6 is
80 -----------------------
81 -- Local Subprograms --
82 -----------------------
84 procedure Add_Access_Actual_To_Build_In_Place_Call
85 (Function_Call : Node_Id;
86 Function_Id : Entity_Id;
87 Return_Object : Node_Id;
88 Is_Access : Boolean := False);
89 -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the
90 -- object name given by Return_Object and add the attribute to the end of
91 -- the actual parameter list associated with the build-in-place function
92 -- call denoted by Function_Call. However, if Is_Access is True, then
93 -- Return_Object is already an access expression, in which case it's passed
94 -- along directly to the build-in-place function. Finally, if Return_Object
95 -- is empty, then pass a null literal as the actual.
97 procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call
98 (Function_Call : Node_Id;
99 Function_Id : Entity_Id;
100 Alloc_Form : BIP_Allocation_Form := Unspecified;
101 Alloc_Form_Exp : Node_Id := Empty;
102 Pool_Actual : Node_Id := Make_Null (No_Location));
103 -- Ada 2005 (AI-318-02): Add the actuals needed for a build-in-place
104 -- function call that returns a caller-unknown-size result (BIP_Alloc_Form
105 -- and BIP_Storage_Pool). If Alloc_Form_Exp is present, then use it,
106 -- otherwise pass a literal corresponding to the Alloc_Form parameter
107 -- (which must not be Unspecified in that case). Pool_Actual is the
108 -- parameter to pass to BIP_Storage_Pool.
110 procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call
111 (Func_Call : Node_Id;
113 Ptr_Typ : Entity_Id := Empty;
114 Master_Exp : Node_Id := Empty);
115 -- Ada 2005 (AI-318-02): If the result type of a build-in-place call needs
116 -- finalization actions, add an actual parameter which is a pointer to the
117 -- finalization master of the caller. If Master_Exp is not Empty, then that
118 -- will be passed as the actual. Otherwise, if Ptr_Typ is left Empty, this
119 -- will result in an automatic "null" value for the actual.
121 procedure Add_Task_Actuals_To_Build_In_Place_Call
122 (Function_Call : Node_Id;
123 Function_Id : Entity_Id;
124 Master_Actual : Node_Id);
125 -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type
126 -- contains tasks, add two actual parameters: the master, and a pointer to
127 -- the caller's activation chain. Master_Actual is the actual parameter
128 -- expression to pass for the master. In most cases, this is the current
129 -- master (_master). The two exceptions are: If the function call is the
130 -- initialization expression for an allocator, we pass the master of the
131 -- access type. If the function call is the initialization expression for a
132 -- return object, we pass along the master passed in by the caller. The
133 -- activation chain to pass is always the local one. Note: Master_Actual
134 -- can be Empty, but only if there are no tasks.
136 procedure Check_Overriding_Operation (Subp : Entity_Id);
137 -- Subp is a dispatching operation. Check whether it may override an
138 -- inherited private operation, in which case its DT entry is that of
139 -- the hidden operation, not the one it may have received earlier.
140 -- This must be done before emitting the code to set the corresponding
141 -- DT to the address of the subprogram. The actual placement of Subp in
142 -- the proper place in the list of primitive operations is done in
143 -- Declare_Inherited_Private_Subprograms, which also has to deal with
144 -- implicit operations. This duplication is unavoidable for now???
146 procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id);
147 -- This procedure is called only if the subprogram body N, whose spec
148 -- has the given entity Spec, contains a parameterless recursive call.
149 -- It attempts to generate runtime code to detect if this a case of
150 -- infinite recursion.
152 -- The body is scanned to determine dependencies. If the only external
153 -- dependencies are on a small set of scalar variables, then the values
154 -- of these variables are captured on entry to the subprogram, and if
155 -- the values are not changed for the call, we know immediately that
156 -- we have an infinite recursion.
158 procedure Expand_Ctrl_Function_Call (N : Node_Id);
159 -- N is a function call which returns a controlled object. Transform the
160 -- call into a temporary which retrieves the returned object from the
161 -- secondary stack using 'reference.
163 procedure Expand_Inlined_Call
166 Orig_Subp : Entity_Id);
167 -- If called subprogram can be inlined by the front-end, retrieve the
168 -- analyzed body, replace formals with actuals and expand call in place.
169 -- Generate thunks for actuals that are expressions, and insert the
170 -- corresponding constant declarations before the call. If the original
171 -- call is to a derived operation, the return type is the one of the
172 -- derived operation, but the body is that of the original, so return
173 -- expressions in the body must be converted to the desired type (which
174 -- is simply not noted in the tree without inline expansion).
176 procedure Expand_Non_Function_Return (N : Node_Id);
177 -- Called by Expand_N_Simple_Return_Statement in case we're returning from
178 -- a procedure body, entry body, accept statement, or extended return
179 -- statement. Note that all non-function returns are simple return
182 function Expand_Protected_Object_Reference
184 Scop : Entity_Id) return Node_Id;
186 procedure Expand_Protected_Subprogram_Call
190 -- A call to a protected subprogram within the protected object may appear
191 -- as a regular call. The list of actuals must be expanded to contain a
192 -- reference to the object itself, and the call becomes a call to the
193 -- corresponding protected subprogram.
195 function Has_Unconstrained_Access_Discriminants
196 (Subtyp : Entity_Id) return Boolean;
197 -- Returns True if the given subtype is unconstrained and has one
198 -- or more access discriminants.
200 procedure Expand_Simple_Function_Return (N : Node_Id);
201 -- Expand simple return from function. In the case where we are returning
202 -- from a function body this is called by Expand_N_Simple_Return_Statement.
204 ----------------------------------------------
205 -- Add_Access_Actual_To_Build_In_Place_Call --
206 ----------------------------------------------
208 procedure Add_Access_Actual_To_Build_In_Place_Call
209 (Function_Call : Node_Id;
210 Function_Id : Entity_Id;
211 Return_Object : Node_Id;
212 Is_Access : Boolean := False)
214 Loc : constant Source_Ptr := Sloc (Function_Call);
215 Obj_Address : Node_Id;
216 Obj_Acc_Formal : Entity_Id;
219 -- Locate the implicit access parameter in the called function
221 Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access);
223 -- If no return object is provided, then pass null
225 if not Present (Return_Object) then
226 Obj_Address := Make_Null (Loc);
227 Set_Parent (Obj_Address, Function_Call);
229 -- If Return_Object is already an expression of an access type, then use
230 -- it directly, since it must be an access value denoting the return
231 -- object, and couldn't possibly be the return object itself.
234 Obj_Address := Return_Object;
235 Set_Parent (Obj_Address, Function_Call);
237 -- Apply Unrestricted_Access to caller's return object
241 Make_Attribute_Reference (Loc,
242 Prefix => Return_Object,
243 Attribute_Name => Name_Unrestricted_Access);
245 Set_Parent (Return_Object, Obj_Address);
246 Set_Parent (Obj_Address, Function_Call);
249 Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal));
251 -- Build the parameter association for the new actual and add it to the
252 -- end of the function's actuals.
254 Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address);
255 end Add_Access_Actual_To_Build_In_Place_Call;
257 ------------------------------------------------------
258 -- Add_Unconstrained_Actuals_To_Build_In_Place_Call --
259 ------------------------------------------------------
261 procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call
262 (Function_Call : Node_Id;
263 Function_Id : Entity_Id;
264 Alloc_Form : BIP_Allocation_Form := Unspecified;
265 Alloc_Form_Exp : Node_Id := Empty;
266 Pool_Actual : Node_Id := Make_Null (No_Location))
268 Loc : constant Source_Ptr := Sloc (Function_Call);
269 Alloc_Form_Actual : Node_Id;
270 Alloc_Form_Formal : Node_Id;
271 Pool_Formal : Node_Id;
274 -- The allocation form generally doesn't need to be passed in the case
275 -- of a constrained result subtype, since normally the caller performs
276 -- the allocation in that case. However this formal is still needed in
277 -- the case where the function has a tagged result, because generally
278 -- such functions can be called in a dispatching context and such calls
279 -- must be handled like calls to class-wide functions.
281 if Is_Constrained (Underlying_Type (Etype (Function_Id)))
282 and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id)))
287 -- Locate the implicit allocation form parameter in the called function.
288 -- Maybe it would be better for each implicit formal of a build-in-place
289 -- function to have a flag or a Uint attribute to identify it. ???
291 Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form);
293 if Present (Alloc_Form_Exp) then
294 pragma Assert (Alloc_Form = Unspecified);
296 Alloc_Form_Actual := Alloc_Form_Exp;
299 pragma Assert (Alloc_Form /= Unspecified);
302 Make_Integer_Literal (Loc,
303 Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form)));
306 Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal));
308 -- Build the parameter association for the new actual and add it to the
309 -- end of the function's actuals.
311 Add_Extra_Actual_To_Call
312 (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual);
314 -- Pass the Storage_Pool parameter. This parameter is omitted on
315 -- .NET/JVM/ZFP as those targets do not support pools.
318 and then RTE_Available (RE_Root_Storage_Pool_Ptr)
320 Pool_Formal := Build_In_Place_Formal (Function_Id, BIP_Storage_Pool);
321 Analyze_And_Resolve (Pool_Actual, Etype (Pool_Formal));
322 Add_Extra_Actual_To_Call
323 (Function_Call, Pool_Formal, Pool_Actual);
325 end Add_Unconstrained_Actuals_To_Build_In_Place_Call;
327 -----------------------------------------------------------
328 -- Add_Finalization_Master_Actual_To_Build_In_Place_Call --
329 -----------------------------------------------------------
331 procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call
332 (Func_Call : Node_Id;
334 Ptr_Typ : Entity_Id := Empty;
335 Master_Exp : Node_Id := Empty)
338 if not Needs_BIP_Finalization_Master (Func_Id) then
343 Formal : constant Entity_Id :=
344 Build_In_Place_Formal (Func_Id, BIP_Finalization_Master);
345 Loc : constant Source_Ptr := Sloc (Func_Call);
348 Desig_Typ : Entity_Id;
351 -- If there is a finalization master actual, such as the implicit
352 -- finalization master of an enclosing build-in-place function,
353 -- then this must be added as an extra actual of the call.
355 if Present (Master_Exp) then
356 Actual := Master_Exp;
358 -- Case where the context does not require an actual master
360 elsif No (Ptr_Typ) then
361 Actual := Make_Null (Loc);
364 Desig_Typ := Directly_Designated_Type (Ptr_Typ);
366 -- Check for a library-level access type whose designated type has
367 -- supressed finalization. Such an access types lack a master.
368 -- Pass a null actual to the callee in order to signal a missing
371 if Is_Library_Level_Entity (Ptr_Typ)
372 and then Finalize_Storage_Only (Desig_Typ)
374 Actual := Make_Null (Loc);
376 -- Types in need of finalization actions
378 elsif Needs_Finalization (Desig_Typ) then
380 -- The general mechanism of creating finalization masters for
381 -- anonymous access types is disabled by default, otherwise
382 -- finalization masters will pop all over the place. Such types
383 -- use context-specific masters.
385 if Ekind (Ptr_Typ) = E_Anonymous_Access_Type
386 and then No (Finalization_Master (Ptr_Typ))
388 Build_Finalization_Master
390 Ins_Node => Associated_Node_For_Itype (Ptr_Typ),
391 Encl_Scope => Scope (Ptr_Typ));
394 -- Access-to-controlled types should always have a master
396 pragma Assert (Present (Finalization_Master (Ptr_Typ)));
399 Make_Attribute_Reference (Loc,
401 New_Reference_To (Finalization_Master (Ptr_Typ), Loc),
402 Attribute_Name => Name_Unrestricted_Access);
407 Actual := Make_Null (Loc);
411 Analyze_And_Resolve (Actual, Etype (Formal));
413 -- Build the parameter association for the new actual and add it to
414 -- the end of the function's actuals.
416 Add_Extra_Actual_To_Call (Func_Call, Formal, Actual);
418 end Add_Finalization_Master_Actual_To_Build_In_Place_Call;
420 ------------------------------
421 -- Add_Extra_Actual_To_Call --
422 ------------------------------
424 procedure Add_Extra_Actual_To_Call
425 (Subprogram_Call : Node_Id;
426 Extra_Formal : Entity_Id;
427 Extra_Actual : Node_Id)
429 Loc : constant Source_Ptr := Sloc (Subprogram_Call);
430 Param_Assoc : Node_Id;
434 Make_Parameter_Association (Loc,
435 Selector_Name => New_Occurrence_Of (Extra_Formal, Loc),
436 Explicit_Actual_Parameter => Extra_Actual);
438 Set_Parent (Param_Assoc, Subprogram_Call);
439 Set_Parent (Extra_Actual, Param_Assoc);
441 if Present (Parameter_Associations (Subprogram_Call)) then
442 if Nkind (Last (Parameter_Associations (Subprogram_Call))) =
443 N_Parameter_Association
446 -- Find last named actual, and append
451 L := First_Actual (Subprogram_Call);
452 while Present (L) loop
453 if No (Next_Actual (L)) then
454 Set_Next_Named_Actual (Parent (L), Extra_Actual);
462 Set_First_Named_Actual (Subprogram_Call, Extra_Actual);
465 Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call));
468 Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc));
469 Set_First_Named_Actual (Subprogram_Call, Extra_Actual);
471 end Add_Extra_Actual_To_Call;
473 ---------------------------------------------
474 -- Add_Task_Actuals_To_Build_In_Place_Call --
475 ---------------------------------------------
477 procedure Add_Task_Actuals_To_Build_In_Place_Call
478 (Function_Call : Node_Id;
479 Function_Id : Entity_Id;
480 Master_Actual : Node_Id)
482 Loc : constant Source_Ptr := Sloc (Function_Call);
483 Result_Subt : constant Entity_Id :=
484 Available_View (Etype (Function_Id));
486 Chain_Actual : Node_Id;
487 Chain_Formal : Node_Id;
488 Master_Formal : Node_Id;
491 -- No such extra parameters are needed if there are no tasks
493 if not Has_Task (Result_Subt) then
497 Actual := Master_Actual;
499 -- Use a dummy _master actual in case of No_Task_Hierarchy
501 if Restriction_Active (No_Task_Hierarchy) then
502 Actual := New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc);
504 -- In the case where we use the master associated with an access type,
505 -- the actual is an entity and requires an explicit reference.
507 elsif Nkind (Actual) = N_Defining_Identifier then
508 Actual := New_Reference_To (Actual, Loc);
511 -- Locate the implicit master parameter in the called function
513 Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Task_Master);
514 Analyze_And_Resolve (Actual, Etype (Master_Formal));
516 -- Build the parameter association for the new actual and add it to the
517 -- end of the function's actuals.
519 Add_Extra_Actual_To_Call (Function_Call, Master_Formal, Actual);
521 -- Locate the implicit activation chain parameter in the called function
524 Build_In_Place_Formal (Function_Id, BIP_Activation_Chain);
526 -- Create the actual which is a pointer to the current activation chain
529 Make_Attribute_Reference (Loc,
530 Prefix => Make_Identifier (Loc, Name_uChain),
531 Attribute_Name => Name_Unrestricted_Access);
533 Analyze_And_Resolve (Chain_Actual, Etype (Chain_Formal));
535 -- Build the parameter association for the new actual and add it to the
536 -- end of the function's actuals.
538 Add_Extra_Actual_To_Call (Function_Call, Chain_Formal, Chain_Actual);
539 end Add_Task_Actuals_To_Build_In_Place_Call;
541 -----------------------
542 -- BIP_Formal_Suffix --
543 -----------------------
545 function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is
548 when BIP_Alloc_Form =>
550 when BIP_Storage_Pool =>
551 return "BIPstoragepool";
552 when BIP_Finalization_Master =>
553 return "BIPfinalizationmaster";
554 when BIP_Task_Master =>
555 return "BIPtaskmaster";
556 when BIP_Activation_Chain =>
557 return "BIPactivationchain";
558 when BIP_Object_Access =>
561 end BIP_Formal_Suffix;
563 ---------------------------
564 -- Build_In_Place_Formal --
565 ---------------------------
567 function Build_In_Place_Formal
569 Kind : BIP_Formal_Kind) return Entity_Id
571 Formal_Name : constant Name_Id :=
573 (Chars (Func), BIP_Formal_Suffix (Kind));
574 Extra_Formal : Entity_Id := Extra_Formals (Func);
577 -- Maybe it would be better for each implicit formal of a build-in-place
578 -- function to have a flag or a Uint attribute to identify it. ???
580 -- The return type in the function declaration may have been a limited
581 -- view, and the extra formals for the function were not generated at
582 -- that point. At the point of call the full view must be available and
583 -- the extra formals can be created.
585 if No (Extra_Formal) then
586 Create_Extra_Formals (Func);
587 Extra_Formal := Extra_Formals (Func);
591 pragma Assert (Present (Extra_Formal));
592 exit when Chars (Extra_Formal) = Formal_Name;
594 Next_Formal_With_Extras (Extra_Formal);
598 end Build_In_Place_Formal;
600 --------------------------------
601 -- Check_Overriding_Operation --
602 --------------------------------
604 procedure Check_Overriding_Operation (Subp : Entity_Id) is
605 Typ : constant Entity_Id := Find_Dispatching_Type (Subp);
606 Op_List : constant Elist_Id := Primitive_Operations (Typ);
612 if Is_Derived_Type (Typ)
613 and then not Is_Private_Type (Typ)
614 and then In_Open_Scopes (Scope (Etype (Typ)))
615 and then Is_Base_Type (Typ)
617 -- Subp overrides an inherited private operation if there is an
618 -- inherited operation with a different name than Subp (see
619 -- Derive_Subprogram) whose Alias is a hidden subprogram with the
620 -- same name as Subp.
622 Op_Elmt := First_Elmt (Op_List);
623 while Present (Op_Elmt) loop
624 Prim_Op := Node (Op_Elmt);
625 Par_Op := Alias (Prim_Op);
628 and then not Comes_From_Source (Prim_Op)
629 and then Chars (Prim_Op) /= Chars (Par_Op)
630 and then Chars (Par_Op) = Chars (Subp)
631 and then Is_Hidden (Par_Op)
632 and then Type_Conformant (Prim_Op, Subp)
634 Set_DT_Position (Subp, DT_Position (Prim_Op));
640 end Check_Overriding_Operation;
642 -------------------------------
643 -- Detect_Infinite_Recursion --
644 -------------------------------
646 procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is
647 Loc : constant Source_Ptr := Sloc (N);
649 Var_List : constant Elist_Id := New_Elmt_List;
650 -- List of globals referenced by body of procedure
652 Call_List : constant Elist_Id := New_Elmt_List;
653 -- List of recursive calls in body of procedure
655 Shad_List : constant Elist_Id := New_Elmt_List;
656 -- List of entity id's for entities created to capture the value of
657 -- referenced globals on entry to the procedure.
659 Scop : constant Uint := Scope_Depth (Spec);
660 -- This is used to record the scope depth of the current procedure, so
661 -- that we can identify global references.
663 Max_Vars : constant := 4;
664 -- Do not test more than four global variables
666 Count_Vars : Natural := 0;
667 -- Count variables found so far
679 function Process (Nod : Node_Id) return Traverse_Result;
680 -- Function to traverse the subprogram body (using Traverse_Func)
686 function Process (Nod : Node_Id) return Traverse_Result is
690 if Nkind (Nod) = N_Procedure_Call_Statement then
692 -- Case of one of the detected recursive calls
694 if Is_Entity_Name (Name (Nod))
695 and then Has_Recursive_Call (Entity (Name (Nod)))
696 and then Entity (Name (Nod)) = Spec
698 Append_Elmt (Nod, Call_List);
701 -- Any other procedure call may have side effects
707 -- A call to a pure function can always be ignored
709 elsif Nkind (Nod) = N_Function_Call
710 and then Is_Entity_Name (Name (Nod))
711 and then Is_Pure (Entity (Name (Nod)))
715 -- Case of an identifier reference
717 elsif Nkind (Nod) = N_Identifier then
720 -- If no entity, then ignore the reference
722 -- Not clear why this can happen. To investigate, remove this
723 -- test and look at the crash that occurs here in 3401-004 ???
728 -- Ignore entities with no Scope, again not clear how this
729 -- can happen, to investigate, look at 4108-008 ???
731 elsif No (Scope (Ent)) then
734 -- Ignore the reference if not to a more global object
736 elsif Scope_Depth (Scope (Ent)) >= Scop then
739 -- References to types, exceptions and constants are always OK
742 or else Ekind (Ent) = E_Exception
743 or else Ekind (Ent) = E_Constant
747 -- If other than a non-volatile scalar variable, we have some
748 -- kind of global reference (e.g. to a function) that we cannot
749 -- deal with so we forget the attempt.
751 elsif Ekind (Ent) /= E_Variable
752 or else not Is_Scalar_Type (Etype (Ent))
753 or else Treat_As_Volatile (Ent)
757 -- Otherwise we have a reference to a global scalar
760 -- Loop through global entities already detected
762 Elm := First_Elmt (Var_List);
764 -- If not detected before, record this new global reference
767 Count_Vars := Count_Vars + 1;
769 if Count_Vars <= Max_Vars then
770 Append_Elmt (Entity (Nod), Var_List);
777 -- If recorded before, ignore
779 elsif Node (Elm) = Entity (Nod) then
782 -- Otherwise keep looking
792 -- For all other node kinds, recursively visit syntactic children
799 function Traverse_Body is new Traverse_Func (Process);
801 -- Start of processing for Detect_Infinite_Recursion
804 -- Do not attempt detection in No_Implicit_Conditional mode, since we
805 -- won't be able to generate the code to handle the recursion in any
808 if Restriction_Active (No_Implicit_Conditionals) then
812 -- Otherwise do traversal and quit if we get abandon signal
814 if Traverse_Body (N) = Abandon then
817 -- We must have a call, since Has_Recursive_Call was set. If not just
818 -- ignore (this is only an error check, so if we have a funny situation,
819 -- due to bugs or errors, we do not want to bomb!)
821 elsif Is_Empty_Elmt_List (Call_List) then
825 -- Here is the case where we detect recursion at compile time
827 -- Push our current scope for analyzing the declarations and code that
828 -- we will insert for the checking.
832 -- This loop builds temporary variables for each of the referenced
833 -- globals, so that at the end of the loop the list Shad_List contains
834 -- these temporaries in one-to-one correspondence with the elements in
838 Elm := First_Elmt (Var_List);
839 while Present (Elm) loop
841 Ent := Make_Temporary (Loc, 'S');
842 Append_Elmt (Ent, Shad_List);
844 -- Insert a declaration for this temporary at the start of the
845 -- declarations for the procedure. The temporaries are declared as
846 -- constant objects initialized to the current values of the
847 -- corresponding temporaries.
850 Make_Object_Declaration (Loc,
851 Defining_Identifier => Ent,
852 Object_Definition => New_Occurrence_Of (Etype (Var), Loc),
853 Constant_Present => True,
854 Expression => New_Occurrence_Of (Var, Loc));
857 Prepend (Decl, Declarations (N));
859 Insert_After (Last, Decl);
867 -- Loop through calls
869 Call := First_Elmt (Call_List);
870 while Present (Call) loop
872 -- Build a predicate expression of the form
875 -- and then global1 = temp1
876 -- and then global2 = temp2
879 -- This predicate determines if any of the global values
880 -- referenced by the procedure have changed since the
881 -- current call, if not an infinite recursion is assured.
883 Test := New_Occurrence_Of (Standard_True, Loc);
885 Elm1 := First_Elmt (Var_List);
886 Elm2 := First_Elmt (Shad_List);
887 while Present (Elm1) loop
893 Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc),
894 Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc)));
900 -- Now we replace the call with the sequence
902 -- if no-changes (see above) then
903 -- raise Storage_Error;
908 Rewrite (Node (Call),
909 Make_If_Statement (Loc,
911 Then_Statements => New_List (
912 Make_Raise_Storage_Error (Loc,
913 Reason => SE_Infinite_Recursion)),
915 Else_Statements => New_List (
916 Relocate_Node (Node (Call)))));
918 Analyze (Node (Call));
923 -- Remove temporary scope stack entry used for analysis
926 end Detect_Infinite_Recursion;
932 procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id) is
933 Loc : constant Source_Ptr := Sloc (N);
938 E_Formal : Entity_Id;
940 procedure Add_Call_By_Copy_Code;
941 -- For cases where the parameter must be passed by copy, this routine
942 -- generates a temporary variable into which the actual is copied and
943 -- then passes this as the parameter. For an OUT or IN OUT parameter,
944 -- an assignment is also generated to copy the result back. The call
945 -- also takes care of any constraint checks required for the type
946 -- conversion case (on both the way in and the way out).
948 procedure Add_Simple_Call_By_Copy_Code;
949 -- This is similar to the above, but is used in cases where we know
950 -- that all that is needed is to simply create a temporary and copy
951 -- the value in and out of the temporary.
953 procedure Check_Fortran_Logical;
954 -- A value of type Logical that is passed through a formal parameter
955 -- must be normalized because .TRUE. usually does not have the same
956 -- representation as True. We assume that .FALSE. = False = 0.
957 -- What about functions that return a logical type ???
959 function Is_Legal_Copy return Boolean;
960 -- Check that an actual can be copied before generating the temporary
961 -- to be used in the call. If the actual is of a by_reference type then
962 -- the program is illegal (this can only happen in the presence of
963 -- rep. clauses that force an incorrect alignment). If the formal is
964 -- a by_reference parameter imposed by a DEC pragma, emit a warning to
965 -- the effect that this might lead to unaligned arguments.
967 function Make_Var (Actual : Node_Id) return Entity_Id;
968 -- Returns an entity that refers to the given actual parameter,
969 -- Actual (not including any type conversion). If Actual is an
970 -- entity name, then this entity is returned unchanged, otherwise
971 -- a renaming is created to provide an entity for the actual.
973 procedure Reset_Packed_Prefix;
974 -- The expansion of a packed array component reference is delayed in
975 -- the context of a call. Now we need to complete the expansion, so we
976 -- unmark the analyzed bits in all prefixes.
978 ---------------------------
979 -- Add_Call_By_Copy_Code --
980 ---------------------------
982 procedure Add_Call_By_Copy_Code is
988 F_Typ : constant Entity_Id := Etype (Formal);
993 if not Is_Legal_Copy then
997 Temp := Make_Temporary (Loc, 'T', Actual);
999 -- Use formal type for temp, unless formal type is an unconstrained
1000 -- array, in which case we don't have to worry about bounds checks,
1001 -- and we use the actual type, since that has appropriate bounds.
1003 if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then
1004 Indic := New_Occurrence_Of (Etype (Actual), Loc);
1006 Indic := New_Occurrence_Of (Etype (Formal), Loc);
1009 if Nkind (Actual) = N_Type_Conversion then
1010 V_Typ := Etype (Expression (Actual));
1012 -- If the formal is an (in-)out parameter, capture the name
1013 -- of the variable in order to build the post-call assignment.
1015 Var := Make_Var (Expression (Actual));
1017 Crep := not Same_Representation
1018 (F_Typ, Etype (Expression (Actual)));
1021 V_Typ := Etype (Actual);
1022 Var := Make_Var (Actual);
1026 -- Setup initialization for case of in out parameter, or an out
1027 -- parameter where the formal is an unconstrained array (in the
1028 -- latter case, we have to pass in an object with bounds).
1030 -- If this is an out parameter, the initial copy is wasteful, so as
1031 -- an optimization for the one-dimensional case we extract the
1032 -- bounds of the actual and build an uninitialized temporary of the
1035 if Ekind (Formal) = E_In_Out_Parameter
1036 or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ))
1038 if Nkind (Actual) = N_Type_Conversion then
1039 if Conversion_OK (Actual) then
1040 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1042 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1045 elsif Ekind (Formal) = E_Out_Parameter
1046 and then Is_Array_Type (F_Typ)
1047 and then Number_Dimensions (F_Typ) = 1
1048 and then not Has_Non_Null_Base_Init_Proc (F_Typ)
1050 -- Actual is a one-dimensional array or slice, and the type
1051 -- requires no initialization. Create a temporary of the
1052 -- right size, but do not copy actual into it (optimization).
1056 Make_Subtype_Indication (Loc,
1058 New_Occurrence_Of (F_Typ, Loc),
1060 Make_Index_Or_Discriminant_Constraint (Loc,
1061 Constraints => New_List (
1064 Make_Attribute_Reference (Loc,
1065 Prefix => New_Occurrence_Of (Var, Loc),
1066 Attribute_Name => Name_First),
1068 Make_Attribute_Reference (Loc,
1069 Prefix => New_Occurrence_Of (Var, Loc),
1070 Attribute_Name => Name_Last)))));
1073 Init := New_Occurrence_Of (Var, Loc);
1076 -- An initialization is created for packed conversions as
1077 -- actuals for out parameters to enable Make_Object_Declaration
1078 -- to determine the proper subtype for N_Node. Note that this
1079 -- is wasteful because the extra copying on the call side is
1080 -- not required for such out parameters. ???
1082 elsif Ekind (Formal) = E_Out_Parameter
1083 and then Nkind (Actual) = N_Type_Conversion
1084 and then (Is_Bit_Packed_Array (F_Typ)
1086 Is_Bit_Packed_Array (Etype (Expression (Actual))))
1088 if Conversion_OK (Actual) then
1089 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1091 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1094 elsif Ekind (Formal) = E_In_Parameter then
1096 -- Handle the case in which the actual is a type conversion
1098 if Nkind (Actual) = N_Type_Conversion then
1099 if Conversion_OK (Actual) then
1100 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1102 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1105 Init := New_Occurrence_Of (Var, Loc);
1113 Make_Object_Declaration (Loc,
1114 Defining_Identifier => Temp,
1115 Object_Definition => Indic,
1116 Expression => Init);
1117 Set_Assignment_OK (N_Node);
1118 Insert_Action (N, N_Node);
1120 -- Now, normally the deal here is that we use the defining
1121 -- identifier created by that object declaration. There is
1122 -- one exception to this. In the change of representation case
1123 -- the above declaration will end up looking like:
1125 -- temp : type := identifier;
1127 -- And in this case we might as well use the identifier directly
1128 -- and eliminate the temporary. Note that the analysis of the
1129 -- declaration was not a waste of time in that case, since it is
1130 -- what generated the necessary change of representation code. If
1131 -- the change of representation introduced additional code, as in
1132 -- a fixed-integer conversion, the expression is not an identifier
1133 -- and must be kept.
1136 and then Present (Expression (N_Node))
1137 and then Is_Entity_Name (Expression (N_Node))
1139 Temp := Entity (Expression (N_Node));
1140 Rewrite (N_Node, Make_Null_Statement (Loc));
1143 -- For IN parameter, all we do is to replace the actual
1145 if Ekind (Formal) = E_In_Parameter then
1146 Rewrite (Actual, New_Reference_To (Temp, Loc));
1149 -- Processing for OUT or IN OUT parameter
1152 -- Kill current value indications for the temporary variable we
1153 -- created, since we just passed it as an OUT parameter.
1155 Kill_Current_Values (Temp);
1156 Set_Is_Known_Valid (Temp, False);
1158 -- If type conversion, use reverse conversion on exit
1160 if Nkind (Actual) = N_Type_Conversion then
1161 if Conversion_OK (Actual) then
1162 Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc));
1164 Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc));
1167 Expr := New_Occurrence_Of (Temp, Loc);
1170 Rewrite (Actual, New_Reference_To (Temp, Loc));
1173 -- If the actual is a conversion of a packed reference, it may
1174 -- already have been expanded by Remove_Side_Effects, and the
1175 -- resulting variable is a temporary which does not designate
1176 -- the proper out-parameter, which may not be addressable. In
1177 -- that case, generate an assignment to the original expression
1178 -- (before expansion of the packed reference) so that the proper
1179 -- expansion of assignment to a packed component can take place.
1186 if Is_Renaming_Of_Object (Var)
1187 and then Nkind (Renamed_Object (Var)) = N_Selected_Component
1188 and then Is_Entity_Name (Prefix (Renamed_Object (Var)))
1189 and then Nkind (Original_Node (Prefix (Renamed_Object (Var))))
1190 = N_Indexed_Component
1192 Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var))))
1194 Obj := Renamed_Object (Var);
1196 Make_Selected_Component (Loc,
1198 New_Copy_Tree (Original_Node (Prefix (Obj))),
1199 Selector_Name => New_Copy (Selector_Name (Obj)));
1200 Reset_Analyzed_Flags (Lhs);
1203 Lhs := New_Occurrence_Of (Var, Loc);
1206 Set_Assignment_OK (Lhs);
1208 if Is_Access_Type (E_Formal)
1209 and then Is_Entity_Name (Lhs)
1211 Present (Effective_Extra_Accessibility (Entity (Lhs)))
1213 -- Copyback target is an Ada 2012 stand-alone object
1214 -- of an anonymous access type
1216 pragma Assert (Ada_Version >= Ada_2012);
1218 if Type_Access_Level (E_Formal) >
1219 Object_Access_Level (Lhs)
1221 Append_To (Post_Call,
1222 Make_Raise_Program_Error (Loc,
1223 Reason => PE_Accessibility_Check_Failed));
1226 Append_To (Post_Call,
1227 Make_Assignment_Statement (Loc,
1229 Expression => Expr));
1231 -- We would like to somehow suppress generation of the
1232 -- extra_accessibility assignment generated by the expansion
1233 -- of the above assignment statement. It's not a correctness
1234 -- issue because the following assignment renders it dead,
1235 -- but generating back-to-back assignments to the same
1236 -- target is undesirable. ???
1238 Append_To (Post_Call,
1239 Make_Assignment_Statement (Loc,
1240 Name => New_Occurrence_Of (
1241 Effective_Extra_Accessibility (Entity (Lhs)), Loc),
1242 Expression => Make_Integer_Literal (Loc,
1243 Type_Access_Level (E_Formal))));
1246 Append_To (Post_Call,
1247 Make_Assignment_Statement (Loc,
1249 Expression => Expr));
1253 end Add_Call_By_Copy_Code;
1255 ----------------------------------
1256 -- Add_Simple_Call_By_Copy_Code --
1257 ----------------------------------
1259 procedure Add_Simple_Call_By_Copy_Code is
1267 F_Typ : constant Entity_Id := Etype (Formal);
1270 if not Is_Legal_Copy then
1274 -- Use formal type for temp, unless formal type is an unconstrained
1275 -- array, in which case we don't have to worry about bounds checks,
1276 -- and we use the actual type, since that has appropriate bounds.
1278 if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then
1279 Indic := New_Occurrence_Of (Etype (Actual), Loc);
1281 Indic := New_Occurrence_Of (Etype (Formal), Loc);
1284 -- Prepare to generate code
1286 Reset_Packed_Prefix;
1288 Temp := Make_Temporary (Loc, 'T', Actual);
1289 Incod := Relocate_Node (Actual);
1290 Outcod := New_Copy_Tree (Incod);
1292 -- Generate declaration of temporary variable, initializing it
1293 -- with the input parameter unless we have an OUT formal or
1294 -- this is an initialization call.
1296 -- If the formal is an out parameter with discriminants, the
1297 -- discriminants must be captured even if the rest of the object
1298 -- is in principle uninitialized, because the discriminants may
1299 -- be read by the called subprogram.
1301 if Ekind (Formal) = E_Out_Parameter then
1304 if Has_Discriminants (Etype (Formal)) then
1305 Indic := New_Occurrence_Of (Etype (Actual), Loc);
1308 elsif Inside_Init_Proc then
1310 -- Could use a comment here to match comment below ???
1312 if Nkind (Actual) /= N_Selected_Component
1314 not Has_Discriminant_Dependent_Constraint
1315 (Entity (Selector_Name (Actual)))
1319 -- Otherwise, keep the component in order to generate the proper
1320 -- actual subtype, that depends on enclosing discriminants.
1328 Make_Object_Declaration (Loc,
1329 Defining_Identifier => Temp,
1330 Object_Definition => Indic,
1331 Expression => Incod);
1336 -- If the call is to initialize a component of a composite type,
1337 -- and the component does not depend on discriminants, use the
1338 -- actual type of the component. This is required in case the
1339 -- component is constrained, because in general the formal of the
1340 -- initialization procedure will be unconstrained. Note that if
1341 -- the component being initialized is constrained by an enclosing
1342 -- discriminant, the presence of the initialization in the
1343 -- declaration will generate an expression for the actual subtype.
1345 Set_No_Initialization (Decl);
1346 Set_Object_Definition (Decl,
1347 New_Occurrence_Of (Etype (Actual), Loc));
1350 Insert_Action (N, Decl);
1352 -- The actual is simply a reference to the temporary
1354 Rewrite (Actual, New_Occurrence_Of (Temp, Loc));
1356 -- Generate copy out if OUT or IN OUT parameter
1358 if Ekind (Formal) /= E_In_Parameter then
1360 Rhs := New_Occurrence_Of (Temp, Loc);
1362 -- Deal with conversion
1364 if Nkind (Lhs) = N_Type_Conversion then
1365 Lhs := Expression (Lhs);
1366 Rhs := Convert_To (Etype (Actual), Rhs);
1369 Append_To (Post_Call,
1370 Make_Assignment_Statement (Loc,
1372 Expression => Rhs));
1373 Set_Assignment_OK (Name (Last (Post_Call)));
1375 end Add_Simple_Call_By_Copy_Code;
1377 ---------------------------
1378 -- Check_Fortran_Logical --
1379 ---------------------------
1381 procedure Check_Fortran_Logical is
1382 Logical : constant Entity_Id := Etype (Formal);
1385 -- Note: this is very incomplete, e.g. it does not handle arrays
1386 -- of logical values. This is really not the right approach at all???)
1389 if Convention (Subp) = Convention_Fortran
1390 and then Root_Type (Etype (Formal)) = Standard_Boolean
1391 and then Ekind (Formal) /= E_In_Parameter
1393 Var := Make_Var (Actual);
1394 Append_To (Post_Call,
1395 Make_Assignment_Statement (Loc,
1396 Name => New_Occurrence_Of (Var, Loc),
1398 Unchecked_Convert_To (
1401 Left_Opnd => New_Occurrence_Of (Var, Loc),
1403 Unchecked_Convert_To (
1405 New_Occurrence_Of (Standard_False, Loc))))));
1407 end Check_Fortran_Logical;
1413 function Is_Legal_Copy return Boolean is
1415 -- An attempt to copy a value of such a type can only occur if
1416 -- representation clauses give the actual a misaligned address.
1418 if Is_By_Reference_Type (Etype (Formal)) then
1420 ("misaligned actual cannot be passed by reference", Actual);
1423 -- For users of Starlet, we assume that the specification of by-
1424 -- reference mechanism is mandatory. This may lead to unaligned
1425 -- objects but at least for DEC legacy code it is known to work.
1426 -- The warning will alert users of this code that a problem may
1429 elsif Mechanism (Formal) = By_Reference
1430 and then Is_Valued_Procedure (Scope (Formal))
1433 ("by_reference actual may be misaligned?", Actual);
1445 function Make_Var (Actual : Node_Id) return Entity_Id is
1449 if Is_Entity_Name (Actual) then
1450 return Entity (Actual);
1453 Var := Make_Temporary (Loc, 'T', Actual);
1456 Make_Object_Renaming_Declaration (Loc,
1457 Defining_Identifier => Var,
1459 New_Occurrence_Of (Etype (Actual), Loc),
1460 Name => Relocate_Node (Actual));
1462 Insert_Action (N, N_Node);
1467 -------------------------
1468 -- Reset_Packed_Prefix --
1469 -------------------------
1471 procedure Reset_Packed_Prefix is
1472 Pfx : Node_Id := Actual;
1475 Set_Analyzed (Pfx, False);
1477 not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component);
1478 Pfx := Prefix (Pfx);
1480 end Reset_Packed_Prefix;
1482 -- Start of processing for Expand_Actuals
1485 Post_Call := New_List;
1487 Formal := First_Formal (Subp);
1488 Actual := First_Actual (N);
1489 while Present (Formal) loop
1490 E_Formal := Etype (Formal);
1492 if Is_Scalar_Type (E_Formal)
1493 or else Nkind (Actual) = N_Slice
1495 Check_Fortran_Logical;
1499 elsif Ekind (Formal) /= E_Out_Parameter then
1501 -- The unusual case of the current instance of a protected type
1502 -- requires special handling. This can only occur in the context
1503 -- of a call within the body of a protected operation.
1505 if Is_Entity_Name (Actual)
1506 and then Ekind (Entity (Actual)) = E_Protected_Type
1507 and then In_Open_Scopes (Entity (Actual))
1509 if Scope (Subp) /= Entity (Actual) then
1510 Error_Msg_N ("operation outside protected type may not "
1511 & "call back its protected operations?", Actual);
1515 Expand_Protected_Object_Reference (N, Entity (Actual)));
1518 -- Ada 2005 (AI-318-02): If the actual parameter is a call to a
1519 -- build-in-place function, then a temporary return object needs
1520 -- to be created and access to it must be passed to the function.
1521 -- Currently we limit such functions to those with inherently
1522 -- limited result subtypes, but eventually we plan to expand the
1523 -- functions that are treated as build-in-place to include other
1524 -- composite result types.
1526 if Is_Build_In_Place_Function_Call (Actual) then
1527 Make_Build_In_Place_Call_In_Anonymous_Context (Actual);
1530 Apply_Constraint_Check (Actual, E_Formal);
1532 -- Out parameter case. No constraint checks on access type
1535 elsif Is_Access_Type (E_Formal) then
1540 elsif Has_Discriminants (Base_Type (E_Formal))
1541 or else Has_Non_Null_Base_Init_Proc (E_Formal)
1543 Apply_Constraint_Check (Actual, E_Formal);
1548 Apply_Constraint_Check (Actual, Base_Type (E_Formal));
1551 -- Processing for IN-OUT and OUT parameters
1553 if Ekind (Formal) /= E_In_Parameter then
1555 -- For type conversions of arrays, apply length/range checks
1557 if Is_Array_Type (E_Formal)
1558 and then Nkind (Actual) = N_Type_Conversion
1560 if Is_Constrained (E_Formal) then
1561 Apply_Length_Check (Expression (Actual), E_Formal);
1563 Apply_Range_Check (Expression (Actual), E_Formal);
1567 -- If argument is a type conversion for a type that is passed
1568 -- by copy, then we must pass the parameter by copy.
1570 if Nkind (Actual) = N_Type_Conversion
1572 (Is_Numeric_Type (E_Formal)
1573 or else Is_Access_Type (E_Formal)
1574 or else Is_Enumeration_Type (E_Formal)
1575 or else Is_Bit_Packed_Array (Etype (Formal))
1576 or else Is_Bit_Packed_Array (Etype (Expression (Actual)))
1578 -- Also pass by copy if change of representation
1580 or else not Same_Representation
1582 Etype (Expression (Actual))))
1584 Add_Call_By_Copy_Code;
1586 -- References to components of bit packed arrays are expanded
1587 -- at this point, rather than at the point of analysis of the
1588 -- actuals, to handle the expansion of the assignment to
1589 -- [in] out parameters.
1591 elsif Is_Ref_To_Bit_Packed_Array (Actual) then
1592 Add_Simple_Call_By_Copy_Code;
1594 -- If a non-scalar actual is possibly bit-aligned, we need a copy
1595 -- because the back-end cannot cope with such objects. In other
1596 -- cases where alignment forces a copy, the back-end generates
1597 -- it properly. It should not be generated unconditionally in the
1598 -- front-end because it does not know precisely the alignment
1599 -- requirements of the target, and makes too conservative an
1600 -- estimate, leading to superfluous copies or spurious errors
1601 -- on by-reference parameters.
1603 elsif Nkind (Actual) = N_Selected_Component
1605 Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual)))
1606 and then not Represented_As_Scalar (Etype (Formal))
1608 Add_Simple_Call_By_Copy_Code;
1610 -- References to slices of bit packed arrays are expanded
1612 elsif Is_Ref_To_Bit_Packed_Slice (Actual) then
1613 Add_Call_By_Copy_Code;
1615 -- References to possibly unaligned slices of arrays are expanded
1617 elsif Is_Possibly_Unaligned_Slice (Actual) then
1618 Add_Call_By_Copy_Code;
1620 -- Deal with access types where the actual subtype and the
1621 -- formal subtype are not the same, requiring a check.
1623 -- It is necessary to exclude tagged types because of "downward
1624 -- conversion" errors.
1626 elsif Is_Access_Type (E_Formal)
1627 and then not Same_Type (E_Formal, Etype (Actual))
1628 and then not Is_Tagged_Type (Designated_Type (E_Formal))
1630 Add_Call_By_Copy_Code;
1632 -- If the actual is not a scalar and is marked for volatile
1633 -- treatment, whereas the formal is not volatile, then pass
1634 -- by copy unless it is a by-reference type.
1636 -- Note: we use Is_Volatile here rather than Treat_As_Volatile,
1637 -- because this is the enforcement of a language rule that applies
1638 -- only to "real" volatile variables, not e.g. to the address
1639 -- clause overlay case.
1641 elsif Is_Entity_Name (Actual)
1642 and then Is_Volatile (Entity (Actual))
1643 and then not Is_By_Reference_Type (Etype (Actual))
1644 and then not Is_Scalar_Type (Etype (Entity (Actual)))
1645 and then not Is_Volatile (E_Formal)
1647 Add_Call_By_Copy_Code;
1649 elsif Nkind (Actual) = N_Indexed_Component
1650 and then Is_Entity_Name (Prefix (Actual))
1651 and then Has_Volatile_Components (Entity (Prefix (Actual)))
1653 Add_Call_By_Copy_Code;
1655 -- Add call-by-copy code for the case of scalar out parameters
1656 -- when it is not known at compile time that the subtype of the
1657 -- formal is a subrange of the subtype of the actual (or vice
1658 -- versa for in out parameters), in order to get range checks
1659 -- on such actuals. (Maybe this case should be handled earlier
1660 -- in the if statement???)
1662 elsif Is_Scalar_Type (E_Formal)
1664 (not In_Subrange_Of (E_Formal, Etype (Actual))
1666 (Ekind (Formal) = E_In_Out_Parameter
1667 and then not In_Subrange_Of (Etype (Actual), E_Formal)))
1669 -- Perhaps the setting back to False should be done within
1670 -- Add_Call_By_Copy_Code, since it could get set on other
1671 -- cases occurring above???
1673 if Do_Range_Check (Actual) then
1674 Set_Do_Range_Check (Actual, False);
1677 Add_Call_By_Copy_Code;
1680 -- Processing for IN parameters
1683 -- For IN parameters is in the packed array case, we expand an
1684 -- indexed component (the circuit in Exp_Ch4 deliberately left
1685 -- indexed components appearing as actuals untouched, so that
1686 -- the special processing above for the OUT and IN OUT cases
1687 -- could be performed. We could make the test in Exp_Ch4 more
1688 -- complex and have it detect the parameter mode, but it is
1689 -- easier simply to handle all cases here.)
1691 if Nkind (Actual) = N_Indexed_Component
1692 and then Is_Packed (Etype (Prefix (Actual)))
1694 Reset_Packed_Prefix;
1695 Expand_Packed_Element_Reference (Actual);
1697 -- If we have a reference to a bit packed array, we copy it, since
1698 -- the actual must be byte aligned.
1700 -- Is this really necessary in all cases???
1702 elsif Is_Ref_To_Bit_Packed_Array (Actual) then
1703 Add_Simple_Call_By_Copy_Code;
1705 -- If a non-scalar actual is possibly unaligned, we need a copy
1707 elsif Is_Possibly_Unaligned_Object (Actual)
1708 and then not Represented_As_Scalar (Etype (Formal))
1710 Add_Simple_Call_By_Copy_Code;
1712 -- Similarly, we have to expand slices of packed arrays here
1713 -- because the result must be byte aligned.
1715 elsif Is_Ref_To_Bit_Packed_Slice (Actual) then
1716 Add_Call_By_Copy_Code;
1718 -- Only processing remaining is to pass by copy if this is a
1719 -- reference to a possibly unaligned slice, since the caller
1720 -- expects an appropriately aligned argument.
1722 elsif Is_Possibly_Unaligned_Slice (Actual) then
1723 Add_Call_By_Copy_Code;
1725 -- An unusual case: a current instance of an enclosing task can be
1726 -- an actual, and must be replaced by a reference to self.
1728 elsif Is_Entity_Name (Actual)
1729 and then Is_Task_Type (Entity (Actual))
1731 if In_Open_Scopes (Entity (Actual)) then
1733 (Make_Function_Call (Loc,
1734 Name => New_Reference_To (RTE (RE_Self), Loc))));
1737 -- A task type cannot otherwise appear as an actual
1740 raise Program_Error;
1745 Next_Formal (Formal);
1746 Next_Actual (Actual);
1749 -- Find right place to put post call stuff if it is present
1751 if not Is_Empty_List (Post_Call) then
1753 -- If call is not a list member, it must be the triggering statement
1754 -- of a triggering alternative or an entry call alternative, and we
1755 -- can add the post call stuff to the corresponding statement list.
1757 if not Is_List_Member (N) then
1759 P : constant Node_Id := Parent (N);
1762 pragma Assert (Nkind_In (P, N_Triggering_Alternative,
1763 N_Entry_Call_Alternative));
1765 if Is_Non_Empty_List (Statements (P)) then
1766 Insert_List_Before_And_Analyze
1767 (First (Statements (P)), Post_Call);
1769 Set_Statements (P, Post_Call);
1773 -- Otherwise, normal case where N is in a statement sequence,
1774 -- just put the post-call stuff after the call statement.
1777 Insert_Actions_After (N, Post_Call);
1781 -- The call node itself is re-analyzed in Expand_Call
1789 -- This procedure handles expansion of function calls and procedure call
1790 -- statements (i.e. it serves as the body for Expand_N_Function_Call and
1791 -- Expand_N_Procedure_Call_Statement). Processing for calls includes:
1793 -- Replace call to Raise_Exception by Raise_Exception_Always if possible
1794 -- Provide values of actuals for all formals in Extra_Formals list
1795 -- Replace "call" to enumeration literal function by literal itself
1796 -- Rewrite call to predefined operator as operator
1797 -- Replace actuals to in-out parameters that are numeric conversions,
1798 -- with explicit assignment to temporaries before and after the call.
1799 -- Remove optional actuals if First_Optional_Parameter specified.
1801 -- Note that the list of actuals has been filled with default expressions
1802 -- during semantic analysis of the call. Only the extra actuals required
1803 -- for the 'Constrained attribute and for accessibility checks are added
1806 procedure Expand_Call (N : Node_Id) is
1807 Loc : constant Source_Ptr := Sloc (N);
1808 Call_Node : Node_Id := N;
1809 Extra_Actuals : List_Id := No_List;
1810 Prev : Node_Id := Empty;
1812 procedure Add_Actual_Parameter (Insert_Param : Node_Id);
1813 -- Adds one entry to the end of the actual parameter list. Used for
1814 -- default parameters and for extra actuals (for Extra_Formals). The
1815 -- argument is an N_Parameter_Association node.
1817 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id);
1818 -- Adds an extra actual to the list of extra actuals. Expr is the
1819 -- expression for the value of the actual, EF is the entity for the
1822 function Inherited_From_Formal (S : Entity_Id) return Entity_Id;
1823 -- Within an instance, a type derived from a non-tagged formal derived
1824 -- type inherits from the original parent, not from the actual. The
1825 -- current derivation mechanism has the derived type inherit from the
1826 -- actual, which is only correct outside of the instance. If the
1827 -- subprogram is inherited, we test for this particular case through a
1828 -- convoluted tree traversal before setting the proper subprogram to be
1831 function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean;
1832 -- Determine if Subp denotes a non-dispatching call to a Deep routine
1834 function New_Value (From : Node_Id) return Node_Id;
1835 -- From is the original Expression. New_Value is equivalent to a call
1836 -- to Duplicate_Subexpr with an explicit dereference when From is an
1837 -- access parameter.
1839 --------------------------
1840 -- Add_Actual_Parameter --
1841 --------------------------
1843 procedure Add_Actual_Parameter (Insert_Param : Node_Id) is
1844 Actual_Expr : constant Node_Id :=
1845 Explicit_Actual_Parameter (Insert_Param);
1848 -- Case of insertion is first named actual
1850 if No (Prev) or else
1851 Nkind (Parent (Prev)) /= N_Parameter_Association
1853 Set_Next_Named_Actual
1854 (Insert_Param, First_Named_Actual (Call_Node));
1855 Set_First_Named_Actual (Call_Node, Actual_Expr);
1858 if No (Parameter_Associations (Call_Node)) then
1859 Set_Parameter_Associations (Call_Node, New_List);
1862 Append (Insert_Param, Parameter_Associations (Call_Node));
1865 Insert_After (Prev, Insert_Param);
1868 -- Case of insertion is not first named actual
1871 Set_Next_Named_Actual
1872 (Insert_Param, Next_Named_Actual (Parent (Prev)));
1873 Set_Next_Named_Actual (Parent (Prev), Actual_Expr);
1874 Append (Insert_Param, Parameter_Associations (Call_Node));
1877 Prev := Actual_Expr;
1878 end Add_Actual_Parameter;
1880 ----------------------
1881 -- Add_Extra_Actual --
1882 ----------------------
1884 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is
1885 Loc : constant Source_Ptr := Sloc (Expr);
1888 if Extra_Actuals = No_List then
1889 Extra_Actuals := New_List;
1890 Set_Parent (Extra_Actuals, Call_Node);
1893 Append_To (Extra_Actuals,
1894 Make_Parameter_Association (Loc,
1895 Selector_Name => Make_Identifier (Loc, Chars (EF)),
1896 Explicit_Actual_Parameter => Expr));
1898 Analyze_And_Resolve (Expr, Etype (EF));
1900 if Nkind (Call_Node) = N_Function_Call then
1901 Set_Is_Accessibility_Actual (Parent (Expr));
1903 end Add_Extra_Actual;
1905 ---------------------------
1906 -- Inherited_From_Formal --
1907 ---------------------------
1909 function Inherited_From_Formal (S : Entity_Id) return Entity_Id is
1911 Gen_Par : Entity_Id;
1912 Gen_Prim : Elist_Id;
1917 -- If the operation is inherited, it is attached to the corresponding
1918 -- type derivation. If the parent in the derivation is a generic
1919 -- actual, it is a subtype of the actual, and we have to recover the
1920 -- original derived type declaration to find the proper parent.
1922 if Nkind (Parent (S)) /= N_Full_Type_Declaration
1923 or else not Is_Derived_Type (Defining_Identifier (Parent (S)))
1924 or else Nkind (Type_Definition (Original_Node (Parent (S)))) /=
1925 N_Derived_Type_Definition
1926 or else not In_Instance
1933 (Type_Definition (Original_Node (Parent (S))));
1935 if Nkind (Indic) = N_Subtype_Indication then
1936 Par := Entity (Subtype_Mark (Indic));
1938 Par := Entity (Indic);
1942 if not Is_Generic_Actual_Type (Par)
1943 or else Is_Tagged_Type (Par)
1944 or else Nkind (Parent (Par)) /= N_Subtype_Declaration
1945 or else not In_Open_Scopes (Scope (Par))
1949 Gen_Par := Generic_Parent_Type (Parent (Par));
1952 -- If the actual has no generic parent type, the formal is not
1953 -- a formal derived type, so nothing to inherit.
1955 if No (Gen_Par) then
1959 -- If the generic parent type is still the generic type, this is a
1960 -- private formal, not a derived formal, and there are no operations
1961 -- inherited from the formal.
1963 if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then
1967 Gen_Prim := Collect_Primitive_Operations (Gen_Par);
1969 Elmt := First_Elmt (Gen_Prim);
1970 while Present (Elmt) loop
1971 if Chars (Node (Elmt)) = Chars (S) then
1977 F1 := First_Formal (S);
1978 F2 := First_Formal (Node (Elmt));
1980 and then Present (F2)
1982 if Etype (F1) = Etype (F2)
1983 or else Etype (F2) = Gen_Par
1989 exit; -- not the right subprogram
2001 raise Program_Error;
2002 end Inherited_From_Formal;
2004 -------------------------
2005 -- Is_Direct_Deep_Call --
2006 -------------------------
2008 function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean is
2010 if Is_TSS (Subp, TSS_Deep_Adjust)
2011 or else Is_TSS (Subp, TSS_Deep_Finalize)
2012 or else Is_TSS (Subp, TSS_Deep_Initialize)
2019 Actual := First (Parameter_Associations (N));
2020 Formal := First_Formal (Subp);
2021 while Present (Actual)
2022 and then Present (Formal)
2024 if Nkind (Actual) = N_Identifier
2025 and then Is_Controlling_Actual (Actual)
2026 and then Etype (Actual) = Etype (Formal)
2032 Next_Formal (Formal);
2038 end Is_Direct_Deep_Call;
2044 function New_Value (From : Node_Id) return Node_Id is
2045 Res : constant Node_Id := Duplicate_Subexpr (From);
2047 if Is_Access_Type (Etype (From)) then
2049 Make_Explicit_Dereference (Sloc (From),
2058 Curr_S : constant Entity_Id := Current_Scope;
2059 Remote : constant Boolean := Is_Remote_Call (Call_Node);
2062 Orig_Subp : Entity_Id := Empty;
2063 Param_Count : Natural := 0;
2064 Parent_Formal : Entity_Id;
2065 Parent_Subp : Entity_Id;
2069 Prev_Orig : Node_Id;
2070 -- Original node for an actual, which may have been rewritten. If the
2071 -- actual is a function call that has been transformed from a selected
2072 -- component, the original node is unanalyzed. Otherwise, it carries
2073 -- semantic information used to generate additional actuals.
2075 CW_Interface_Formals_Present : Boolean := False;
2077 -- Start of processing for Expand_Call
2080 -- Ignore if previous error
2082 if Nkind (Call_Node) in N_Has_Etype
2083 and then Etype (Call_Node) = Any_Type
2088 -- Call using access to subprogram with explicit dereference
2090 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
2091 Subp := Etype (Name (Call_Node));
2092 Parent_Subp := Empty;
2094 -- Case of call to simple entry, where the Name is a selected component
2095 -- whose prefix is the task, and whose selector name is the entry name
2097 elsif Nkind (Name (Call_Node)) = N_Selected_Component then
2098 Subp := Entity (Selector_Name (Name (Call_Node)));
2099 Parent_Subp := Empty;
2101 -- Case of call to member of entry family, where Name is an indexed
2102 -- component, with the prefix being a selected component giving the
2103 -- task and entry family name, and the index being the entry index.
2105 elsif Nkind (Name (Call_Node)) = N_Indexed_Component then
2106 Subp := Entity (Selector_Name (Prefix (Name (Call_Node))));
2107 Parent_Subp := Empty;
2112 Subp := Entity (Name (Call_Node));
2113 Parent_Subp := Alias (Subp);
2115 -- Replace call to Raise_Exception by call to Raise_Exception_Always
2116 -- if we can tell that the first parameter cannot possibly be null.
2117 -- This improves efficiency by avoiding a run-time test.
2119 -- We do not do this if Raise_Exception_Always does not exist, which
2120 -- can happen in configurable run time profiles which provide only a
2123 if Is_RTE (Subp, RE_Raise_Exception)
2124 and then RTE_Available (RE_Raise_Exception_Always)
2127 FA : constant Node_Id :=
2128 Original_Node (First_Actual (Call_Node));
2131 -- The case we catch is where the first argument is obtained
2132 -- using the Identity attribute (which must always be
2135 if Nkind (FA) = N_Attribute_Reference
2136 and then Attribute_Name (FA) = Name_Identity
2138 Subp := RTE (RE_Raise_Exception_Always);
2139 Set_Name (Call_Node, New_Occurrence_Of (Subp, Loc));
2144 if Ekind (Subp) = E_Entry then
2145 Parent_Subp := Empty;
2149 -- Detect the following code in System.Finalization_Masters only on
2150 -- .NET/JVM targets:
2152 -- procedure Finalize (Master : in out Finalization_Master) is
2156 -- Finalize (Curr_Ptr.all);
2158 -- Since .NET/JVM compilers lack address arithmetic and Deep_Finalize
2159 -- cannot be named in library or user code, the compiler has to install
2160 -- a kludge and transform the call to Finalize into Deep_Finalize.
2162 if VM_Target /= No_VM
2163 and then Chars (Subp) = Name_Finalize
2164 and then Ekind (Curr_S) = E_Block
2165 and then Ekind (Scope (Curr_S)) = E_Procedure
2166 and then Chars (Scope (Curr_S)) = Name_Finalize
2167 and then Etype (First_Formal (Scope (Curr_S))) =
2168 RTE (RE_Finalization_Master)
2171 Deep_Fin : constant Entity_Id :=
2172 Find_Prim_Op (RTE (RE_Root_Controlled),
2175 -- Since Root_Controlled is a tagged type, the compiler should
2176 -- always generate Deep_Finalize for it.
2178 pragma Assert (Present (Deep_Fin));
2181 -- Deep_Finalize (Curr_Ptr.all);
2184 Make_Procedure_Call_Statement (Loc,
2186 New_Reference_To (Deep_Fin, Loc),
2187 Parameter_Associations =>
2188 New_Copy_List_Tree (Parameter_Associations (N))));
2195 -- Ada 2005 (AI-345): We have a procedure call as a triggering
2196 -- alternative in an asynchronous select or as an entry call in
2197 -- a conditional or timed select. Check whether the procedure call
2198 -- is a renaming of an entry and rewrite it as an entry call.
2200 if Ada_Version >= Ada_2005
2201 and then Nkind (Call_Node) = N_Procedure_Call_Statement
2203 ((Nkind (Parent (Call_Node)) = N_Triggering_Alternative
2204 and then Triggering_Statement (Parent (Call_Node)) = Call_Node)
2206 (Nkind (Parent (Call_Node)) = N_Entry_Call_Alternative
2207 and then Entry_Call_Statement (Parent (Call_Node)) = Call_Node))
2211 Ren_Root : Entity_Id := Subp;
2214 -- This may be a chain of renamings, find the root
2216 if Present (Alias (Ren_Root)) then
2217 Ren_Root := Alias (Ren_Root);
2220 if Present (Original_Node (Parent (Parent (Ren_Root)))) then
2221 Ren_Decl := Original_Node (Parent (Parent (Ren_Root)));
2223 if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then
2225 Make_Entry_Call_Statement (Loc,
2227 New_Copy_Tree (Name (Ren_Decl)),
2228 Parameter_Associations =>
2230 (Parameter_Associations (Call_Node))));
2238 -- First step, compute extra actuals, corresponding to any Extra_Formals
2239 -- present. Note that we do not access Extra_Formals directly, instead
2240 -- we simply note the presence of the extra formals as we process the
2241 -- regular formals collecting corresponding actuals in Extra_Actuals.
2243 -- We also generate any required range checks for actuals for in formals
2244 -- as we go through the loop, since this is a convenient place to do it.
2245 -- (Though it seems that this would be better done in Expand_Actuals???)
2247 Formal := First_Formal (Subp);
2248 Actual := First_Actual (Call_Node);
2250 while Present (Formal) loop
2252 -- Generate range check if required
2254 if Do_Range_Check (Actual)
2255 and then Ekind (Formal) = E_In_Parameter
2257 Set_Do_Range_Check (Actual, False);
2258 Generate_Range_Check
2259 (Actual, Etype (Formal), CE_Range_Check_Failed);
2262 -- Prepare to examine current entry
2265 Prev_Orig := Original_Node (Prev);
2267 -- Ada 2005 (AI-251): Check if any formal is a class-wide interface
2268 -- to expand it in a further round.
2270 CW_Interface_Formals_Present :=
2271 CW_Interface_Formals_Present
2273 (Ekind (Etype (Formal)) = E_Class_Wide_Type
2274 and then Is_Interface (Etype (Etype (Formal))))
2276 (Ekind (Etype (Formal)) = E_Anonymous_Access_Type
2277 and then Is_Interface (Directly_Designated_Type
2278 (Etype (Etype (Formal)))));
2280 -- Create possible extra actual for constrained case. Usually, the
2281 -- extra actual is of the form actual'constrained, but since this
2282 -- attribute is only available for unconstrained records, TRUE is
2283 -- expanded if the type of the formal happens to be constrained (for
2284 -- instance when this procedure is inherited from an unconstrained
2285 -- record to a constrained one) or if the actual has no discriminant
2286 -- (its type is constrained). An exception to this is the case of a
2287 -- private type without discriminants. In this case we pass FALSE
2288 -- because the object has underlying discriminants with defaults.
2290 if Present (Extra_Constrained (Formal)) then
2291 if Ekind (Etype (Prev)) in Private_Kind
2292 and then not Has_Discriminants (Base_Type (Etype (Prev)))
2295 (New_Occurrence_Of (Standard_False, Loc),
2296 Extra_Constrained (Formal));
2298 elsif Is_Constrained (Etype (Formal))
2299 or else not Has_Discriminants (Etype (Prev))
2302 (New_Occurrence_Of (Standard_True, Loc),
2303 Extra_Constrained (Formal));
2305 -- Do not produce extra actuals for Unchecked_Union parameters.
2306 -- Jump directly to the end of the loop.
2308 elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then
2309 goto Skip_Extra_Actual_Generation;
2312 -- If the actual is a type conversion, then the constrained
2313 -- test applies to the actual, not the target type.
2319 -- Test for unchecked conversions as well, which can occur
2320 -- as out parameter actuals on calls to stream procedures.
2323 while Nkind_In (Act_Prev, N_Type_Conversion,
2324 N_Unchecked_Type_Conversion)
2326 Act_Prev := Expression (Act_Prev);
2329 -- If the expression is a conversion of a dereference, this
2330 -- is internally generated code that manipulates addresses,
2331 -- e.g. when building interface tables. No check should
2332 -- occur in this case, and the discriminated object is not
2335 if not Comes_From_Source (Actual)
2336 and then Nkind (Actual) = N_Unchecked_Type_Conversion
2337 and then Nkind (Act_Prev) = N_Explicit_Dereference
2340 (New_Occurrence_Of (Standard_False, Loc),
2341 Extra_Constrained (Formal));
2345 (Make_Attribute_Reference (Sloc (Prev),
2347 Duplicate_Subexpr_No_Checks
2348 (Act_Prev, Name_Req => True),
2349 Attribute_Name => Name_Constrained),
2350 Extra_Constrained (Formal));
2356 -- Create possible extra actual for accessibility level
2358 if Present (Extra_Accessibility (Formal)) then
2360 -- Ada 2005 (AI-252): If the actual was rewritten as an Access
2361 -- attribute, then the original actual may be an aliased object
2362 -- occurring as the prefix in a call using "Object.Operation"
2363 -- notation. In that case we must pass the level of the object,
2364 -- so Prev_Orig is reset to Prev and the attribute will be
2365 -- processed by the code for Access attributes further below.
2367 if Prev_Orig /= Prev
2368 and then Nkind (Prev) = N_Attribute_Reference
2370 Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access
2371 and then Is_Aliased_View (Prev_Orig)
2376 -- Ada 2005 (AI-251): Thunks must propagate the extra actuals of
2377 -- accessibility levels.
2379 if Ekind (Current_Scope) in Subprogram_Kind
2380 and then Is_Thunk (Current_Scope)
2383 Parm_Ent : Entity_Id;
2386 if Is_Controlling_Actual (Actual) then
2388 -- Find the corresponding actual of the thunk
2390 Parm_Ent := First_Entity (Current_Scope);
2391 for J in 2 .. Param_Count loop
2392 Next_Entity (Parm_Ent);
2395 else pragma Assert (Is_Entity_Name (Actual));
2396 Parm_Ent := Entity (Actual);
2400 (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc),
2401 Extra_Accessibility (Formal));
2404 elsif Is_Entity_Name (Prev_Orig) then
2406 -- When passing an access parameter, or a renaming of an access
2407 -- parameter, as the actual to another access parameter we need
2408 -- to pass along the actual's own access level parameter. This
2409 -- is done if we are within the scope of the formal access
2410 -- parameter (if this is an inlined body the extra formal is
2413 if (Is_Formal (Entity (Prev_Orig))
2415 (Present (Renamed_Object (Entity (Prev_Orig)))
2417 Is_Entity_Name (Renamed_Object (Entity (Prev_Orig)))
2420 (Entity (Renamed_Object (Entity (Prev_Orig))))))
2421 and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type
2422 and then In_Open_Scopes (Scope (Entity (Prev_Orig)))
2425 Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig);
2428 pragma Assert (Present (Parm_Ent));
2430 if Present (Extra_Accessibility (Parm_Ent)) then
2433 (Extra_Accessibility (Parm_Ent), Loc),
2434 Extra_Accessibility (Formal));
2436 -- If the actual access parameter does not have an
2437 -- associated extra formal providing its scope level,
2438 -- then treat the actual as having library-level
2443 (Make_Integer_Literal (Loc,
2444 Intval => Scope_Depth (Standard_Standard)),
2445 Extra_Accessibility (Formal));
2449 -- The actual is a normal access value, so just pass the level
2450 -- of the actual's access type.
2454 (Dynamic_Accessibility_Level (Prev_Orig),
2455 Extra_Accessibility (Formal));
2458 -- If the actual is an access discriminant, then pass the level
2459 -- of the enclosing object (RM05-3.10.2(12.4/2)).
2461 elsif Nkind (Prev_Orig) = N_Selected_Component
2462 and then Ekind (Entity (Selector_Name (Prev_Orig))) =
2464 and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) =
2465 E_Anonymous_Access_Type
2468 (Make_Integer_Literal (Loc,
2469 Intval => Object_Access_Level (Prefix (Prev_Orig))),
2470 Extra_Accessibility (Formal));
2475 case Nkind (Prev_Orig) is
2477 when N_Attribute_Reference =>
2478 case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is
2480 -- For X'Access, pass on the level of the prefix X
2482 when Attribute_Access =>
2484 -- If this is an Access attribute applied to the
2485 -- the current instance object passed to a type
2486 -- initialization procedure, then use the level
2487 -- of the type itself. This is not really correct,
2488 -- as there should be an extra level parameter
2489 -- passed in with _init formals (only in the case
2490 -- where the type is immutably limited), but we
2491 -- don't have an easy way currently to create such
2492 -- an extra formal (init procs aren't ever frozen).
2493 -- For now we just use the level of the type,
2494 -- which may be too shallow, but that works better
2495 -- than passing Object_Access_Level of the type,
2496 -- which can be one level too deep in some cases.
2499 if Is_Entity_Name (Prefix (Prev_Orig))
2500 and then Is_Type (Entity (Prefix (Prev_Orig)))
2503 (Make_Integer_Literal (Loc,
2506 (Entity (Prefix (Prev_Orig)))),
2507 Extra_Accessibility (Formal));
2511 (Make_Integer_Literal (Loc,
2514 (Prefix (Prev_Orig))),
2515 Extra_Accessibility (Formal));
2518 -- Treat the unchecked attributes as library-level
2520 when Attribute_Unchecked_Access |
2521 Attribute_Unrestricted_Access =>
2523 (Make_Integer_Literal (Loc,
2524 Intval => Scope_Depth (Standard_Standard)),
2525 Extra_Accessibility (Formal));
2527 -- No other cases of attributes returning access
2528 -- values that can be passed to access parameters.
2531 raise Program_Error;
2535 -- For allocators we pass the level of the execution of the
2536 -- called subprogram, which is one greater than the current
2541 (Make_Integer_Literal (Loc,
2542 Intval => Scope_Depth (Current_Scope) + 1),
2543 Extra_Accessibility (Formal));
2545 -- For most other cases we simply pass the level of the
2546 -- actual's access type. The type is retrieved from
2547 -- Prev rather than Prev_Orig, because in some cases
2548 -- Prev_Orig denotes an original expression that has
2549 -- not been analyzed.
2553 (Dynamic_Accessibility_Level (Prev),
2554 Extra_Accessibility (Formal));
2559 -- Perform the check of 4.6(49) that prevents a null value from being
2560 -- passed as an actual to an access parameter. Note that the check
2561 -- is elided in the common cases of passing an access attribute or
2562 -- access parameter as an actual. Also, we currently don't enforce
2563 -- this check for expander-generated actuals and when -gnatdj is set.
2565 if Ada_Version >= Ada_2005 then
2567 -- Ada 2005 (AI-231): Check null-excluding access types. Note that
2568 -- the intent of 6.4.1(13) is that null-exclusion checks should
2569 -- not be done for 'out' parameters, even though it refers only
2570 -- to constraint checks, and a null_exclusion is not a constraint.
2571 -- Note that AI05-0196-1 corrects this mistake in the RM.
2573 if Is_Access_Type (Etype (Formal))
2574 and then Can_Never_Be_Null (Etype (Formal))
2575 and then Ekind (Formal) /= E_Out_Parameter
2576 and then Nkind (Prev) /= N_Raise_Constraint_Error
2577 and then (Known_Null (Prev)
2578 or else not Can_Never_Be_Null (Etype (Prev)))
2580 Install_Null_Excluding_Check (Prev);
2583 -- Ada_Version < Ada_2005
2586 if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type
2587 or else Access_Checks_Suppressed (Subp)
2591 elsif Debug_Flag_J then
2594 elsif not Comes_From_Source (Prev) then
2597 elsif Is_Entity_Name (Prev)
2598 and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type
2602 elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then
2605 -- Suppress null checks when passing to access parameters of Java
2606 -- and CIL subprograms. (Should this be done for other foreign
2607 -- conventions as well ???)
2609 elsif Convention (Subp) = Convention_Java
2610 or else Convention (Subp) = Convention_CIL
2615 Install_Null_Excluding_Check (Prev);
2619 -- Perform appropriate validity checks on parameters that
2622 if Validity_Checks_On then
2623 if (Ekind (Formal) = E_In_Parameter
2624 and then Validity_Check_In_Params)
2626 (Ekind (Formal) = E_In_Out_Parameter
2627 and then Validity_Check_In_Out_Params)
2629 -- If the actual is an indexed component of a packed type (or
2630 -- is an indexed or selected component whose prefix recursively
2631 -- meets this condition), it has not been expanded yet. It will
2632 -- be copied in the validity code that follows, and has to be
2633 -- expanded appropriately, so reanalyze it.
2635 -- What we do is just to unset analyzed bits on prefixes till
2636 -- we reach something that does not have a prefix.
2643 while Nkind_In (Nod, N_Indexed_Component,
2644 N_Selected_Component)
2646 Set_Analyzed (Nod, False);
2647 Nod := Prefix (Nod);
2651 Ensure_Valid (Actual);
2655 -- For Ada 2012, if a parameter is aliased, the actual must be an
2658 if Is_Aliased (Formal) and then not Is_Aliased_View (Actual) then
2660 ("actual for aliased formal& must be aliased object",
2664 -- For IN OUT and OUT parameters, ensure that subscripts are valid
2665 -- since this is a left side reference. We only do this for calls
2666 -- from the source program since we assume that compiler generated
2667 -- calls explicitly generate any required checks. We also need it
2668 -- only if we are doing standard validity checks, since clearly it is
2669 -- not needed if validity checks are off, and in subscript validity
2670 -- checking mode, all indexed components are checked with a call
2671 -- directly from Expand_N_Indexed_Component.
2673 if Comes_From_Source (Call_Node)
2674 and then Ekind (Formal) /= E_In_Parameter
2675 and then Validity_Checks_On
2676 and then Validity_Check_Default
2677 and then not Validity_Check_Subscripts
2679 Check_Valid_Lvalue_Subscripts (Actual);
2682 -- Mark any scalar OUT parameter that is a simple variable as no
2683 -- longer known to be valid (unless the type is always valid). This
2684 -- reflects the fact that if an OUT parameter is never set in a
2685 -- procedure, then it can become invalid on the procedure return.
2687 if Ekind (Formal) = E_Out_Parameter
2688 and then Is_Entity_Name (Actual)
2689 and then Ekind (Entity (Actual)) = E_Variable
2690 and then not Is_Known_Valid (Etype (Actual))
2692 Set_Is_Known_Valid (Entity (Actual), False);
2695 -- For an OUT or IN OUT parameter, if the actual is an entity, then
2696 -- clear current values, since they can be clobbered. We are probably
2697 -- doing this in more places than we need to, but better safe than
2698 -- sorry when it comes to retaining bad current values!
2700 if Ekind (Formal) /= E_In_Parameter
2701 and then Is_Entity_Name (Actual)
2702 and then Present (Entity (Actual))
2705 Ent : constant Entity_Id := Entity (Actual);
2709 -- For an OUT or IN OUT parameter that is an assignable entity,
2710 -- we do not want to clobber the Last_Assignment field, since
2711 -- if it is set, it was precisely because it is indeed an OUT
2712 -- or IN OUT parameter! We do reset the Is_Known_Valid flag
2713 -- since the subprogram could have returned in invalid value.
2715 if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter)
2716 and then Is_Assignable (Ent)
2718 Sav := Last_Assignment (Ent);
2719 Kill_Current_Values (Ent);
2720 Set_Last_Assignment (Ent, Sav);
2721 Set_Is_Known_Valid (Ent, False);
2723 -- For all other cases, just kill the current values
2726 Kill_Current_Values (Ent);
2731 -- If the formal is class wide and the actual is an aggregate, force
2732 -- evaluation so that the back end who does not know about class-wide
2733 -- type, does not generate a temporary of the wrong size.
2735 if not Is_Class_Wide_Type (Etype (Formal)) then
2738 elsif Nkind (Actual) = N_Aggregate
2739 or else (Nkind (Actual) = N_Qualified_Expression
2740 and then Nkind (Expression (Actual)) = N_Aggregate)
2742 Force_Evaluation (Actual);
2745 -- In a remote call, if the formal is of a class-wide type, check
2746 -- that the actual meets the requirements described in E.4(18).
2748 if Remote and then Is_Class_Wide_Type (Etype (Formal)) then
2749 Insert_Action (Actual,
2750 Make_Transportable_Check (Loc,
2751 Duplicate_Subexpr_Move_Checks (Actual)));
2754 -- This label is required when skipping extra actual generation for
2755 -- Unchecked_Union parameters.
2757 <<Skip_Extra_Actual_Generation>>
2759 Param_Count := Param_Count + 1;
2760 Next_Actual (Actual);
2761 Next_Formal (Formal);
2764 -- If we are calling an Ada2012 function which needs to have the
2765 -- "accessibility level determined by the point of call" (AI05-0234)
2766 -- passed in to it, then pass it in.
2768 if Ekind_In (Subp, E_Function, E_Operator, E_Subprogram_Type)
2770 Present (Extra_Accessibility_Of_Result (Ultimate_Alias (Subp)))
2773 Ancestor : Node_Id := Parent (Call_Node);
2774 Level : Node_Id := Empty;
2775 Defer : Boolean := False;
2778 -- Unimplemented: if Subp returns an anonymous access type, then
2780 -- a) if the call is the operand of an explict conversion, then
2781 -- the target type of the conversion (a named access type)
2782 -- determines the accessibility level pass in;
2784 -- b) if the call defines an access discriminant of an object
2785 -- (e.g., the discriminant of an object being created by an
2786 -- allocator, or the discriminant of a function result),
2787 -- then the accessibility level to pass in is that of the
2788 -- discriminated object being initialized).
2792 while Nkind (Ancestor) = N_Qualified_Expression
2794 Ancestor := Parent (Ancestor);
2797 case Nkind (Ancestor) is
2800 -- At this point, we'd like to assign
2802 -- Level := Dynamic_Accessibility_Level (Ancestor);
2804 -- but Etype of Ancestor may not have been set yet,
2805 -- so that doesn't work.
2807 -- Handle this later in Expand_Allocator_Expression.
2811 when N_Object_Declaration | N_Object_Renaming_Declaration =>
2813 Def_Id : constant Entity_Id :=
2814 Defining_Identifier (Ancestor);
2817 if Is_Return_Object (Def_Id) then
2818 if Present (Extra_Accessibility_Of_Result
2819 (Return_Applies_To (Scope (Def_Id))))
2821 -- Pass along value that was passed in if the
2822 -- routine we are returning from also has an
2823 -- Accessibility_Of_Result formal.
2827 (Extra_Accessibility_Of_Result
2828 (Return_Applies_To (Scope (Def_Id))), Loc);
2832 Make_Integer_Literal (Loc,
2833 Intval => Object_Access_Level (Def_Id));
2837 when N_Simple_Return_Statement =>
2838 if Present (Extra_Accessibility_Of_Result
2840 (Return_Statement_Entity (Ancestor))))
2842 -- Pass along value that was passed in if the routine
2843 -- we are returning from also has an
2844 -- Accessibility_Of_Result formal.
2848 (Extra_Accessibility_Of_Result
2850 (Return_Statement_Entity (Ancestor))), Loc);
2858 if not Present (Level) then
2860 -- The "innermost master that evaluates the function call".
2862 -- ??? - Should we use Integer'Last here instead in order
2863 -- to deal with (some of) the problems associated with
2864 -- calls to subps whose enclosing scope is unknown (e.g.,
2865 -- Anon_Access_To_Subp_Param.all)?
2867 Level := Make_Integer_Literal (Loc,
2868 Scope_Depth (Current_Scope) + 1);
2873 Extra_Accessibility_Of_Result (Ultimate_Alias (Subp)));
2878 -- If we are expanding a rhs of an assignment we need to check if tag
2879 -- propagation is needed. You might expect this processing to be in
2880 -- Analyze_Assignment but has to be done earlier (bottom-up) because the
2881 -- assignment might be transformed to a declaration for an unconstrained
2882 -- value if the expression is classwide.
2884 if Nkind (Call_Node) = N_Function_Call
2885 and then Is_Tag_Indeterminate (Call_Node)
2886 and then Is_Entity_Name (Name (Call_Node))
2889 Ass : Node_Id := Empty;
2892 if Nkind (Parent (Call_Node)) = N_Assignment_Statement then
2893 Ass := Parent (Call_Node);
2895 elsif Nkind (Parent (Call_Node)) = N_Qualified_Expression
2896 and then Nkind (Parent (Parent (Call_Node))) =
2897 N_Assignment_Statement
2899 Ass := Parent (Parent (Call_Node));
2901 elsif Nkind (Parent (Call_Node)) = N_Explicit_Dereference
2902 and then Nkind (Parent (Parent (Call_Node))) =
2903 N_Assignment_Statement
2905 Ass := Parent (Parent (Call_Node));
2909 and then Is_Class_Wide_Type (Etype (Name (Ass)))
2911 if Is_Access_Type (Etype (Call_Node)) then
2912 if Designated_Type (Etype (Call_Node)) /=
2913 Root_Type (Etype (Name (Ass)))
2916 ("tag-indeterminate expression "
2917 & " must have designated type& (RM 5.2 (6))",
2918 Call_Node, Root_Type (Etype (Name (Ass))));
2920 Propagate_Tag (Name (Ass), Call_Node);
2923 elsif Etype (Call_Node) /= Root_Type (Etype (Name (Ass))) then
2925 ("tag-indeterminate expression must have type&"
2927 Call_Node, Root_Type (Etype (Name (Ass))));
2930 Propagate_Tag (Name (Ass), Call_Node);
2933 -- The call will be rewritten as a dispatching call, and
2934 -- expanded as such.
2941 -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand
2942 -- it to point to the correct secondary virtual table
2944 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2945 and then CW_Interface_Formals_Present
2947 Expand_Interface_Actuals (Call_Node);
2950 -- Deals with Dispatch_Call if we still have a call, before expanding
2951 -- extra actuals since this will be done on the re-analysis of the
2952 -- dispatching call. Note that we do not try to shorten the actual list
2953 -- for a dispatching call, it would not make sense to do so. Expansion
2954 -- of dispatching calls is suppressed when VM_Target, because the VM
2955 -- back-ends directly handle the generation of dispatching calls and
2956 -- would have to undo any expansion to an indirect call.
2958 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2959 and then Present (Controlling_Argument (Call_Node))
2962 Call_Typ : constant Entity_Id := Etype (Call_Node);
2963 Typ : constant Entity_Id := Find_Dispatching_Type (Subp);
2964 Eq_Prim_Op : Entity_Id := Empty;
2967 Prev_Call : Node_Id;
2970 if not Is_Limited_Type (Typ) then
2971 Eq_Prim_Op := Find_Prim_Op (Typ, Name_Op_Eq);
2974 if Tagged_Type_Expansion then
2975 Expand_Dispatching_Call (Call_Node);
2977 -- The following return is worrisome. Is it really OK to skip
2978 -- all remaining processing in this procedure ???
2985 Apply_Tag_Checks (Call_Node);
2987 -- If this is a dispatching "=", we must first compare the
2988 -- tags so we generate: x.tag = y.tag and then x = y
2990 if Subp = Eq_Prim_Op then
2992 -- Mark the node as analyzed to avoid reanalizing this
2993 -- dispatching call (which would cause a never-ending loop)
2995 Prev_Call := Relocate_Node (Call_Node);
2996 Set_Analyzed (Prev_Call);
2998 Param := First_Actual (Call_Node);
3004 Make_Selected_Component (Loc,
3005 Prefix => New_Value (Param),
3007 New_Reference_To (First_Tag_Component (Typ),
3011 Make_Selected_Component (Loc,
3013 Unchecked_Convert_To (Typ,
3014 New_Value (Next_Actual (Param))),
3017 (First_Tag_Component (Typ), Loc))),
3018 Right_Opnd => Prev_Call);
3020 Rewrite (Call_Node, New_Call);
3023 (Call_Node, Call_Typ, Suppress => All_Checks);
3026 -- Expansion of a dispatching call results in an indirect call,
3027 -- which in turn causes current values to be killed (see
3028 -- Resolve_Call), so on VM targets we do the call here to
3029 -- ensure consistent warnings between VM and non-VM targets.
3031 Kill_Current_Values;
3034 -- If this is a dispatching "=" then we must update the reference
3035 -- to the call node because we generated:
3036 -- x.tag = y.tag and then x = y
3038 if Subp = Eq_Prim_Op then
3039 Call_Node := Right_Opnd (Call_Node);
3044 -- Similarly, expand calls to RCI subprograms on which pragma
3045 -- All_Calls_Remote applies. The rewriting will be reanalyzed
3046 -- later. Do this only when the call comes from source since we
3047 -- do not want such a rewriting to occur in expanded code.
3049 if Is_All_Remote_Call (Call_Node) then
3050 Expand_All_Calls_Remote_Subprogram_Call (Call_Node);
3052 -- Similarly, do not add extra actuals for an entry call whose entity
3053 -- is a protected procedure, or for an internal protected subprogram
3054 -- call, because it will be rewritten as a protected subprogram call
3055 -- and reanalyzed (see Expand_Protected_Subprogram_Call).
3057 elsif Is_Protected_Type (Scope (Subp))
3058 and then (Ekind (Subp) = E_Procedure
3059 or else Ekind (Subp) = E_Function)
3063 -- During that loop we gathered the extra actuals (the ones that
3064 -- correspond to Extra_Formals), so now they can be appended.
3067 while Is_Non_Empty_List (Extra_Actuals) loop
3068 Add_Actual_Parameter (Remove_Head (Extra_Actuals));
3072 -- At this point we have all the actuals, so this is the point at which
3073 -- the various expansion activities for actuals is carried out.
3075 Expand_Actuals (Call_Node, Subp);
3077 -- If the subprogram is a renaming, or if it is inherited, replace it in
3078 -- the call with the name of the actual subprogram being called. If this
3079 -- is a dispatching call, the run-time decides what to call. The Alias
3080 -- attribute does not apply to entries.
3082 if Nkind (Call_Node) /= N_Entry_Call_Statement
3083 and then No (Controlling_Argument (Call_Node))
3084 and then Present (Parent_Subp)
3085 and then not Is_Direct_Deep_Call (Subp)
3087 if Present (Inherited_From_Formal (Subp)) then
3088 Parent_Subp := Inherited_From_Formal (Subp);
3090 Parent_Subp := Ultimate_Alias (Parent_Subp);
3093 -- The below setting of Entity is suspect, see F109-018 discussion???
3095 Set_Entity (Name (Call_Node), Parent_Subp);
3097 if Is_Abstract_Subprogram (Parent_Subp)
3098 and then not In_Instance
3101 ("cannot call abstract subprogram &!",
3102 Name (Call_Node), Parent_Subp);
3105 -- Inspect all formals of derived subprogram Subp. Compare parameter
3106 -- types with the parent subprogram and check whether an actual may
3107 -- need a type conversion to the corresponding formal of the parent
3110 -- Not clear whether intrinsic subprograms need such conversions. ???
3112 if not Is_Intrinsic_Subprogram (Parent_Subp)
3113 or else Is_Generic_Instance (Parent_Subp)
3116 procedure Convert (Act : Node_Id; Typ : Entity_Id);
3117 -- Rewrite node Act as a type conversion of Act to Typ. Analyze
3118 -- and resolve the newly generated construct.
3124 procedure Convert (Act : Node_Id; Typ : Entity_Id) is
3126 Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act)));
3133 Actual_Typ : Entity_Id;
3134 Formal_Typ : Entity_Id;
3135 Parent_Typ : Entity_Id;
3138 Actual := First_Actual (Call_Node);
3139 Formal := First_Formal (Subp);
3140 Parent_Formal := First_Formal (Parent_Subp);
3141 while Present (Formal) loop
3142 Actual_Typ := Etype (Actual);
3143 Formal_Typ := Etype (Formal);
3144 Parent_Typ := Etype (Parent_Formal);
3146 -- For an IN parameter of a scalar type, the parent formal
3147 -- type and derived formal type differ or the parent formal
3148 -- type and actual type do not match statically.
3150 if Is_Scalar_Type (Formal_Typ)
3151 and then Ekind (Formal) = E_In_Parameter
3152 and then Formal_Typ /= Parent_Typ
3154 not Subtypes_Statically_Match (Parent_Typ, Actual_Typ)
3155 and then not Raises_Constraint_Error (Actual)
3157 Convert (Actual, Parent_Typ);
3158 Enable_Range_Check (Actual);
3160 -- If the actual has been marked as requiring a range
3161 -- check, then generate it here.
3163 if Do_Range_Check (Actual) then
3164 Set_Do_Range_Check (Actual, False);
3165 Generate_Range_Check
3166 (Actual, Etype (Formal), CE_Range_Check_Failed);
3169 -- For access types, the parent formal type and actual type
3172 elsif Is_Access_Type (Formal_Typ)
3173 and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ)
3175 if Ekind (Formal) /= E_In_Parameter then
3176 Convert (Actual, Parent_Typ);
3178 elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type
3179 and then Designated_Type (Parent_Typ) /=
3180 Designated_Type (Actual_Typ)
3181 and then not Is_Controlling_Formal (Formal)
3183 -- This unchecked conversion is not necessary unless
3184 -- inlining is enabled, because in that case the type
3185 -- mismatch may become visible in the body about to be
3189 Unchecked_Convert_To (Parent_Typ,
3190 Relocate_Node (Actual)));
3192 Resolve (Actual, Parent_Typ);
3195 -- For array and record types, the parent formal type and
3196 -- derived formal type have different sizes or pragma Pack
3199 elsif ((Is_Array_Type (Formal_Typ)
3200 and then Is_Array_Type (Parent_Typ))
3202 (Is_Record_Type (Formal_Typ)
3203 and then Is_Record_Type (Parent_Typ)))
3205 (Esize (Formal_Typ) /= Esize (Parent_Typ)
3206 or else Has_Pragma_Pack (Formal_Typ) /=
3207 Has_Pragma_Pack (Parent_Typ))
3209 Convert (Actual, Parent_Typ);
3212 Next_Actual (Actual);
3213 Next_Formal (Formal);
3214 Next_Formal (Parent_Formal);
3220 Subp := Parent_Subp;
3223 -- Check for violation of No_Abort_Statements
3225 if Restriction_Check_Required (No_Abort_Statements)
3226 and then Is_RTE (Subp, RE_Abort_Task)
3228 Check_Restriction (No_Abort_Statements, Call_Node);
3230 -- Check for violation of No_Dynamic_Attachment
3232 elsif Restriction_Check_Required (No_Dynamic_Attachment)
3233 and then RTU_Loaded (Ada_Interrupts)
3234 and then (Is_RTE (Subp, RE_Is_Reserved) or else
3235 Is_RTE (Subp, RE_Is_Attached) or else
3236 Is_RTE (Subp, RE_Current_Handler) or else
3237 Is_RTE (Subp, RE_Attach_Handler) or else
3238 Is_RTE (Subp, RE_Exchange_Handler) or else
3239 Is_RTE (Subp, RE_Detach_Handler) or else
3240 Is_RTE (Subp, RE_Reference))
3242 Check_Restriction (No_Dynamic_Attachment, Call_Node);
3245 -- Deal with case where call is an explicit dereference
3247 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
3249 -- Handle case of access to protected subprogram type
3251 if Is_Access_Protected_Subprogram_Type
3252 (Base_Type (Etype (Prefix (Name (Call_Node)))))
3254 -- If this is a call through an access to protected operation, the
3255 -- prefix has the form (object'address, operation'access). Rewrite
3256 -- as a for other protected calls: the object is the 1st parameter
3257 -- of the list of actuals.
3264 Ptr : constant Node_Id := Prefix (Name (Call_Node));
3266 T : constant Entity_Id :=
3267 Equivalent_Type (Base_Type (Etype (Ptr)));
3269 D_T : constant Entity_Id :=
3270 Designated_Type (Base_Type (Etype (Ptr)));
3274 Make_Selected_Component (Loc,
3275 Prefix => Unchecked_Convert_To (T, Ptr),
3277 New_Occurrence_Of (First_Entity (T), Loc));
3280 Make_Selected_Component (Loc,
3281 Prefix => Unchecked_Convert_To (T, Ptr),
3283 New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc));
3286 Make_Explicit_Dereference (Loc,
3289 if Present (Parameter_Associations (Call_Node)) then
3290 Parm := Parameter_Associations (Call_Node);
3295 Prepend (Obj, Parm);
3297 if Etype (D_T) = Standard_Void_Type then
3299 Make_Procedure_Call_Statement (Loc,
3301 Parameter_Associations => Parm);
3304 Make_Function_Call (Loc,
3306 Parameter_Associations => Parm);
3309 Set_First_Named_Actual (Call, First_Named_Actual (Call_Node));
3310 Set_Etype (Call, Etype (D_T));
3312 -- We do not re-analyze the call to avoid infinite recursion.
3313 -- We analyze separately the prefix and the object, and set
3314 -- the checks on the prefix that would otherwise be emitted
3315 -- when resolving a call.
3317 Rewrite (Call_Node, Call);
3319 Apply_Access_Check (Nam);
3326 -- If this is a call to an intrinsic subprogram, then perform the
3327 -- appropriate expansion to the corresponding tree node and we
3328 -- are all done (since after that the call is gone!)
3330 -- In the case where the intrinsic is to be processed by the back end,
3331 -- the call to Expand_Intrinsic_Call will do nothing, which is fine,
3332 -- since the idea in this case is to pass the call unchanged. If the
3333 -- intrinsic is an inherited unchecked conversion, and the derived type
3334 -- is the target type of the conversion, we must retain it as the return
3335 -- type of the expression. Otherwise the expansion below, which uses the
3336 -- parent operation, will yield the wrong type.
3338 if Is_Intrinsic_Subprogram (Subp) then
3339 Expand_Intrinsic_Call (Call_Node, Subp);
3341 if Nkind (Call_Node) = N_Unchecked_Type_Conversion
3342 and then Parent_Subp /= Orig_Subp
3343 and then Etype (Parent_Subp) /= Etype (Orig_Subp)
3345 Set_Etype (Call_Node, Etype (Orig_Subp));
3351 if Ekind_In (Subp, E_Function, E_Procedure) then
3353 -- We perform two simple optimization on calls:
3355 -- a) replace calls to null procedures unconditionally;
3357 -- b) for To_Address, just do an unchecked conversion. Not only is
3358 -- this efficient, but it also avoids order of elaboration problems
3359 -- when address clauses are inlined (address expression elaborated
3360 -- at the wrong point).
3362 -- We perform these optimization regardless of whether we are in the
3363 -- main unit or in a unit in the context of the main unit, to ensure
3364 -- that tree generated is the same in both cases, for Inspector use.
3366 if Is_RTE (Subp, RE_To_Address) then
3368 Unchecked_Convert_To
3369 (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node))));
3372 elsif Is_Null_Procedure (Subp) then
3373 Rewrite (Call_Node, Make_Null_Statement (Loc));
3377 if Is_Inlined (Subp) then
3379 Inlined_Subprogram : declare
3381 Must_Inline : Boolean := False;
3382 Spec : constant Node_Id := Unit_Declaration_Node (Subp);
3383 Scop : constant Entity_Id := Scope (Subp);
3385 function In_Unfrozen_Instance return Boolean;
3386 -- If the subprogram comes from an instance in the same unit,
3387 -- and the instance is not yet frozen, inlining might trigger
3388 -- order-of-elaboration problems in gigi.
3390 --------------------------
3391 -- In_Unfrozen_Instance --
3392 --------------------------
3394 function In_Unfrozen_Instance return Boolean is
3400 and then S /= Standard_Standard
3402 if Is_Generic_Instance (S)
3403 and then Present (Freeze_Node (S))
3404 and then not Analyzed (Freeze_Node (S))
3413 end In_Unfrozen_Instance;
3415 -- Start of processing for Inlined_Subprogram
3418 -- Verify that the body to inline has already been seen, and
3419 -- that if the body is in the current unit the inlining does
3420 -- not occur earlier. This avoids order-of-elaboration problems
3423 -- This should be documented in sinfo/einfo ???
3426 or else Nkind (Spec) /= N_Subprogram_Declaration
3427 or else No (Body_To_Inline (Spec))
3429 Must_Inline := False;
3431 -- If this an inherited function that returns a private type,
3432 -- do not inline if the full view is an unconstrained array,
3433 -- because such calls cannot be inlined.
3435 elsif Present (Orig_Subp)
3436 and then Is_Array_Type (Etype (Orig_Subp))
3437 and then not Is_Constrained (Etype (Orig_Subp))
3439 Must_Inline := False;
3441 elsif In_Unfrozen_Instance then
3442 Must_Inline := False;
3445 Bod := Body_To_Inline (Spec);
3447 if (In_Extended_Main_Code_Unit (Call_Node)
3448 or else In_Extended_Main_Code_Unit (Parent (Call_Node))
3449 or else Has_Pragma_Inline_Always (Subp))
3450 and then (not In_Same_Extended_Unit (Sloc (Bod), Loc)
3452 Earlier_In_Extended_Unit (Sloc (Bod), Loc))
3454 Must_Inline := True;
3456 -- If we are compiling a package body that is not the main
3457 -- unit, it must be for inlining/instantiation purposes,
3458 -- in which case we inline the call to insure that the same
3459 -- temporaries are generated when compiling the body by
3460 -- itself. Otherwise link errors can occur.
3462 -- If the function being called is itself in the main unit,
3463 -- we cannot inline, because there is a risk of double
3464 -- elaboration and/or circularity: the inlining can make
3465 -- visible a private entity in the body of the main unit,
3466 -- that gigi will see before its sees its proper definition.
3468 elsif not (In_Extended_Main_Code_Unit (Call_Node))
3469 and then In_Package_Body
3471 Must_Inline := not In_Extended_Main_Source_Unit (Subp);
3476 Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);
3479 -- Let the back end handle it
3481 Add_Inlined_Body (Subp);
3483 if Front_End_Inlining
3484 and then Nkind (Spec) = N_Subprogram_Declaration
3485 and then (In_Extended_Main_Code_Unit (Call_Node))
3486 and then No (Body_To_Inline (Spec))
3487 and then not Has_Completion (Subp)
3488 and then In_Same_Extended_Unit (Sloc (Spec), Loc)
3491 ("cannot inline& (body not seen yet)?", Call_Node, Subp);
3494 end Inlined_Subprogram;
3498 -- Check for protected subprogram. This is either an intra-object call,
3499 -- or a protected function call. Protected procedure calls are rewritten
3500 -- as entry calls and handled accordingly.
3502 -- In Ada 2005, this may be an indirect call to an access parameter that
3503 -- is an access_to_subprogram. In that case the anonymous type has a
3504 -- scope that is a protected operation, but the call is a regular one.
3505 -- In either case do not expand call if subprogram is eliminated.
3507 Scop := Scope (Subp);
3509 if Nkind (Call_Node) /= N_Entry_Call_Statement
3510 and then Is_Protected_Type (Scop)
3511 and then Ekind (Subp) /= E_Subprogram_Type
3512 and then not Is_Eliminated (Subp)
3514 -- If the call is an internal one, it is rewritten as a call to the
3515 -- corresponding unprotected subprogram.
3517 Expand_Protected_Subprogram_Call (Call_Node, Subp, Scop);
3520 -- Functions returning controlled objects need special attention. If
3521 -- the return type is limited, then the context is initialization and
3522 -- different processing applies. If the call is to a protected function,
3523 -- the expansion above will call Expand_Call recursively. Otherwise the
3524 -- function call is transformed into a temporary which obtains the
3525 -- result from the secondary stack.
3527 if Needs_Finalization (Etype (Subp)) then
3528 if not Is_Immutably_Limited_Type (Etype (Subp))
3530 (No (First_Formal (Subp))
3532 not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
3534 Expand_Ctrl_Function_Call (Call_Node);
3536 -- Build-in-place function calls which appear in anonymous contexts
3537 -- need a transient scope to ensure the proper finalization of the
3538 -- intermediate result after its use.
3540 elsif Is_Build_In_Place_Function_Call (Call_Node)
3541 and then Nkind_In (Parent (Call_Node), N_Attribute_Reference,
3543 N_Indexed_Component,
3544 N_Object_Renaming_Declaration,
3545 N_Procedure_Call_Statement,
3546 N_Selected_Component,
3549 Establish_Transient_Scope (Call_Node, Sec_Stack => True);
3553 -- Test for First_Optional_Parameter, and if so, truncate parameter list
3554 -- if there are optional parameters at the trailing end.
3555 -- Note: we never delete procedures for call via a pointer.
3557 if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function)
3558 and then Present (First_Optional_Parameter (Subp))
3561 Last_Keep_Arg : Node_Id;
3564 -- Last_Keep_Arg will hold the last actual that should be kept.
3565 -- If it remains empty at the end, it means that all parameters
3568 Last_Keep_Arg := Empty;
3570 -- Find first optional parameter, must be present since we checked
3571 -- the validity of the parameter before setting it.
3573 Formal := First_Formal (Subp);
3574 Actual := First_Actual (Call_Node);
3575 while Formal /= First_Optional_Parameter (Subp) loop
3576 Last_Keep_Arg := Actual;
3577 Next_Formal (Formal);
3578 Next_Actual (Actual);
3581 -- We have Formal and Actual pointing to the first potentially
3582 -- droppable argument. We can drop all the trailing arguments
3583 -- whose actual matches the default. Note that we know that all
3584 -- remaining formals have defaults, because we checked that this
3585 -- requirement was met before setting First_Optional_Parameter.
3587 -- We use Fully_Conformant_Expressions to check for identity
3588 -- between formals and actuals, which may miss some cases, but
3589 -- on the other hand, this is only an optimization (if we fail
3590 -- to truncate a parameter it does not affect functionality).
3591 -- So if the default is 3 and the actual is 1+2, we consider
3592 -- them unequal, which hardly seems worrisome.
3594 while Present (Formal) loop
3595 if not Fully_Conformant_Expressions
3596 (Actual, Default_Value (Formal))
3598 Last_Keep_Arg := Actual;
3601 Next_Formal (Formal);
3602 Next_Actual (Actual);
3605 -- If no arguments, delete entire list, this is the easy case
3607 if No (Last_Keep_Arg) then
3608 Set_Parameter_Associations (Call_Node, No_List);
3609 Set_First_Named_Actual (Call_Node, Empty);
3611 -- Case where at the last retained argument is positional. This
3612 -- is also an easy case, since the retained arguments are already
3613 -- in the right form, and we don't need to worry about the order
3614 -- of arguments that get eliminated.
3616 elsif Is_List_Member (Last_Keep_Arg) then
3617 while Present (Next (Last_Keep_Arg)) loop
3618 Discard_Node (Remove_Next (Last_Keep_Arg));
3621 Set_First_Named_Actual (Call_Node, Empty);
3623 -- This is the annoying case where the last retained argument
3624 -- is a named parameter. Since the original arguments are not
3625 -- in declaration order, we may have to delete some fairly
3626 -- random collection of arguments.
3634 -- First step, remove all the named parameters from the
3635 -- list (they are still chained using First_Named_Actual
3636 -- and Next_Named_Actual, so we have not lost them!)
3638 Temp := First (Parameter_Associations (Call_Node));
3640 -- Case of all parameters named, remove them all
3642 if Nkind (Temp) = N_Parameter_Association then
3643 -- Suppress warnings to avoid warning on possible
3644 -- infinite loop (because Call_Node is not modified).
3646 pragma Warnings (Off);
3647 while Is_Non_Empty_List
3648 (Parameter_Associations (Call_Node))
3651 Remove_Head (Parameter_Associations (Call_Node));
3653 pragma Warnings (On);
3655 -- Case of mixed positional/named, remove named parameters
3658 while Nkind (Next (Temp)) /= N_Parameter_Association loop
3662 while Present (Next (Temp)) loop
3663 Remove (Next (Temp));
3667 -- Now we loop through the named parameters, till we get
3668 -- to the last one to be retained, adding them to the list.
3669 -- Note that the Next_Named_Actual list does not need to be
3670 -- touched since we are only reordering them on the actual
3671 -- parameter association list.
3673 Passoc := Parent (First_Named_Actual (Call_Node));
3675 Temp := Relocate_Node (Passoc);
3677 (Parameter_Associations (Call_Node), Temp);
3679 Last_Keep_Arg = Explicit_Actual_Parameter (Passoc);
3680 Passoc := Parent (Next_Named_Actual (Passoc));
3683 Set_Next_Named_Actual (Temp, Empty);
3686 Temp := Next_Named_Actual (Passoc);
3687 exit when No (Temp);
3688 Set_Next_Named_Actual
3689 (Passoc, Next_Named_Actual (Parent (Temp)));
3698 -------------------------------
3699 -- Expand_Ctrl_Function_Call --
3700 -------------------------------
3702 procedure Expand_Ctrl_Function_Call (N : Node_Id) is
3704 -- Optimization, if the returned value (which is on the sec-stack) is
3705 -- returned again, no need to copy/readjust/finalize, we can just pass
3706 -- the value thru (see Expand_N_Simple_Return_Statement), and thus no
3707 -- attachment is needed
3709 if Nkind (Parent (N)) = N_Simple_Return_Statement then
3713 -- Resolution is now finished, make sure we don't start analysis again
3714 -- because of the duplication.
3718 -- A function which returns a controlled object uses the secondary
3719 -- stack. Rewrite the call into a temporary which obtains the result of
3720 -- the function using 'reference.
3722 Remove_Side_Effects (N);
3723 end Expand_Ctrl_Function_Call;
3725 --------------------------
3726 -- Expand_Inlined_Call --
3727 --------------------------
3729 procedure Expand_Inlined_Call
3732 Orig_Subp : Entity_Id)
3734 Loc : constant Source_Ptr := Sloc (N);
3735 Is_Predef : constant Boolean :=
3736 Is_Predefined_File_Name
3737 (Unit_File_Name (Get_Source_Unit (Subp)));
3738 Orig_Bod : constant Node_Id :=
3739 Body_To_Inline (Unit_Declaration_Node (Subp));
3744 Decls : constant List_Id := New_List;
3745 Exit_Lab : Entity_Id := Empty;
3752 Ret_Type : Entity_Id;
3755 -- The target of the call. If context is an assignment statement then
3756 -- this is the left-hand side of the assignment. else it is a temporary
3757 -- to which the return value is assigned prior to rewriting the call.
3760 -- A separate target used when the return type is unconstrained
3763 Temp_Typ : Entity_Id;
3765 Return_Object : Entity_Id := Empty;
3766 -- Entity in declaration in an extended_return_statement
3768 Is_Unc : constant Boolean :=
3769 Is_Array_Type (Etype (Subp))
3770 and then not Is_Constrained (Etype (Subp));
3771 -- If the type returned by the function is unconstrained and the call
3772 -- can be inlined, special processing is required.
3774 procedure Make_Exit_Label;
3775 -- Build declaration for exit label to be used in Return statements,
3776 -- sets Exit_Lab (the label node) and Lab_Decl (corresponding implicit
3777 -- declaration). Does nothing if Exit_Lab already set.
3779 function Process_Formals (N : Node_Id) return Traverse_Result;
3780 -- Replace occurrence of a formal with the corresponding actual, or the
3781 -- thunk generated for it.
3783 function Process_Sloc (Nod : Node_Id) return Traverse_Result;
3784 -- If the call being expanded is that of an internal subprogram, set the
3785 -- sloc of the generated block to that of the call itself, so that the
3786 -- expansion is skipped by the "next" command in gdb.
3787 -- Same processing for a subprogram in a predefined file, e.g.
3788 -- Ada.Tags. If Debug_Generated_Code is true, suppress this change to
3789 -- simplify our own development.
3791 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id);
3792 -- If the function body is a single expression, replace call with
3793 -- expression, else insert block appropriately.
3795 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id);
3796 -- If procedure body has no local variables, inline body without
3797 -- creating block, otherwise rewrite call with block.
3799 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean;
3800 -- Determine whether a formal parameter is used only once in Orig_Bod
3802 ---------------------
3803 -- Make_Exit_Label --
3804 ---------------------
3806 procedure Make_Exit_Label is
3807 Lab_Ent : Entity_Id;
3809 if No (Exit_Lab) then
3810 Lab_Ent := Make_Temporary (Loc, 'L');
3811 Lab_Id := New_Reference_To (Lab_Ent, Loc);
3812 Exit_Lab := Make_Label (Loc, Lab_Id);
3814 Make_Implicit_Label_Declaration (Loc,
3815 Defining_Identifier => Lab_Ent,
3816 Label_Construct => Exit_Lab);
3818 end Make_Exit_Label;
3820 ---------------------
3821 -- Process_Formals --
3822 ---------------------
3824 function Process_Formals (N : Node_Id) return Traverse_Result is
3830 if Is_Entity_Name (N)
3831 and then Present (Entity (N))
3836 and then Scope (E) = Subp
3838 A := Renamed_Object (E);
3840 -- Rewrite the occurrence of the formal into an occurrence of
3841 -- the actual. Also establish visibility on the proper view of
3842 -- the actual's subtype for the body's context (if the actual's
3843 -- subtype is private at the call point but its full view is
3844 -- visible to the body, then the inlined tree here must be
3845 -- analyzed with the full view).
3847 if Is_Entity_Name (A) then
3848 Rewrite (N, New_Occurrence_Of (Entity (A), Loc));
3849 Check_Private_View (N);
3851 elsif Nkind (A) = N_Defining_Identifier then
3852 Rewrite (N, New_Occurrence_Of (A, Loc));
3853 Check_Private_View (N);
3858 Rewrite (N, New_Copy (A));
3864 elsif Is_Entity_Name (N)
3865 and then Present (Return_Object)
3866 and then Chars (N) = Chars (Return_Object)
3868 -- Occurrence within an extended return statement. The return
3869 -- object is local to the body been inlined, and thus the generic
3870 -- copy is not analyzed yet, so we match by name, and replace it
3871 -- with target of call.
3873 if Nkind (Targ) = N_Defining_Identifier then
3874 Rewrite (N, New_Occurrence_Of (Targ, Loc));
3876 Rewrite (N, New_Copy_Tree (Targ));
3881 elsif Nkind (N) = N_Simple_Return_Statement then
3882 if No (Expression (N)) then
3885 Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id)));
3888 if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements
3889 and then Nkind (Parent (Parent (N))) = N_Subprogram_Body
3891 -- Function body is a single expression. No need for
3897 Num_Ret := Num_Ret + 1;
3901 -- Because of the presence of private types, the views of the
3902 -- expression and the context may be different, so place an
3903 -- unchecked conversion to the context type to avoid spurious
3904 -- errors, e.g. when the expression is a numeric literal and
3905 -- the context is private. If the expression is an aggregate,
3906 -- use a qualified expression, because an aggregate is not a
3907 -- legal argument of a conversion.
3909 if Nkind_In (Expression (N), N_Aggregate, N_Null) then
3911 Make_Qualified_Expression (Sloc (N),
3912 Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)),
3913 Expression => Relocate_Node (Expression (N)));
3916 Unchecked_Convert_To
3917 (Ret_Type, Relocate_Node (Expression (N)));
3920 if Nkind (Targ) = N_Defining_Identifier then
3922 Make_Assignment_Statement (Loc,
3923 Name => New_Occurrence_Of (Targ, Loc),
3924 Expression => Ret));
3927 Make_Assignment_Statement (Loc,
3928 Name => New_Copy (Targ),
3929 Expression => Ret));
3932 Set_Assignment_OK (Name (N));
3934 if Present (Exit_Lab) then
3936 Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id)));
3942 -- An extended return becomes a block whose first statement is the
3943 -- assignment of the initial expression of the return object to the
3944 -- target of the call itself.
3946 elsif Nkind (N) = N_Extended_Return_Statement then
3948 Return_Decl : constant Entity_Id :=
3949 First (Return_Object_Declarations (N));
3953 Return_Object := Defining_Identifier (Return_Decl);
3955 if Present (Expression (Return_Decl)) then
3956 if Nkind (Targ) = N_Defining_Identifier then
3958 Make_Assignment_Statement (Loc,
3959 Name => New_Occurrence_Of (Targ, Loc),
3960 Expression => Expression (Return_Decl));
3963 Make_Assignment_Statement (Loc,
3964 Name => New_Copy (Targ),
3965 Expression => Expression (Return_Decl));
3968 Set_Assignment_OK (Name (Assign));
3970 Statements (Handled_Statement_Sequence (N)));
3974 Make_Block_Statement (Loc,
3975 Handled_Statement_Sequence =>
3976 Handled_Statement_Sequence (N)));
3981 -- Remove pragma Unreferenced since it may refer to formals that
3982 -- are not visible in the inlined body, and in any case we will
3983 -- not be posting warnings on the inlined body so it is unneeded.
3985 elsif Nkind (N) = N_Pragma
3986 and then Pragma_Name (N) = Name_Unreferenced
3988 Rewrite (N, Make_Null_Statement (Sloc (N)));
3994 end Process_Formals;
3996 procedure Replace_Formals is new Traverse_Proc (Process_Formals);
4002 function Process_Sloc (Nod : Node_Id) return Traverse_Result is
4004 if not Debug_Generated_Code then
4005 Set_Sloc (Nod, Sloc (N));
4006 Set_Comes_From_Source (Nod, False);
4012 procedure Reset_Slocs is new Traverse_Proc (Process_Sloc);
4014 ---------------------------
4015 -- Rewrite_Function_Call --
4016 ---------------------------
4018 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is
4019 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
4020 Fst : constant Node_Id := First (Statements (HSS));
4023 -- Optimize simple case: function body is a single return statement,
4024 -- which has been expanded into an assignment.
4026 if Is_Empty_List (Declarations (Blk))
4027 and then Nkind (Fst) = N_Assignment_Statement
4028 and then No (Next (Fst))
4030 -- The function call may have been rewritten as the temporary
4031 -- that holds the result of the call, in which case remove the
4032 -- now useless declaration.
4034 if Nkind (N) = N_Identifier
4035 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
4037 Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc));
4040 Rewrite (N, Expression (Fst));
4042 elsif Nkind (N) = N_Identifier
4043 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
4045 -- The block assigns the result of the call to the temporary
4047 Insert_After (Parent (Entity (N)), Blk);
4049 -- If the context is an assignment, and the left-hand side is free of
4050 -- side-effects, the replacement is also safe.
4051 -- Can this be generalized further???
4053 elsif Nkind (Parent (N)) = N_Assignment_Statement
4055 (Is_Entity_Name (Name (Parent (N)))
4057 (Nkind (Name (Parent (N))) = N_Explicit_Dereference
4058 and then Is_Entity_Name (Prefix (Name (Parent (N)))))
4061 (Nkind (Name (Parent (N))) = N_Selected_Component
4062 and then Is_Entity_Name (Prefix (Name (Parent (N))))))
4064 -- Replace assignment with the block
4067 Original_Assignment : constant Node_Id := Parent (N);
4070 -- Preserve the original assignment node to keep the complete
4071 -- assignment subtree consistent enough for Analyze_Assignment
4072 -- to proceed (specifically, the original Lhs node must still
4073 -- have an assignment statement as its parent).
4075 -- We cannot rely on Original_Node to go back from the block
4076 -- node to the assignment node, because the assignment might
4077 -- already be a rewrite substitution.
4079 Discard_Node (Relocate_Node (Original_Assignment));
4080 Rewrite (Original_Assignment, Blk);
4083 elsif Nkind (Parent (N)) = N_Object_Declaration then
4084 Set_Expression (Parent (N), Empty);
4085 Insert_After (Parent (N), Blk);
4088 Insert_Before (Parent (N), Blk);
4090 end Rewrite_Function_Call;
4092 ----------------------------
4093 -- Rewrite_Procedure_Call --
4094 ----------------------------
4096 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is
4097 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
4100 -- If there is a transient scope for N, this will be the scope of the
4101 -- actions for N, and the statements in Blk need to be within this
4102 -- scope. For example, they need to have visibility on the constant
4103 -- declarations created for the formals.
4105 -- If N needs no transient scope, and if there are no declarations in
4106 -- the inlined body, we can do a little optimization and insert the
4107 -- statements for the body directly after N, and rewrite N to a
4108 -- null statement, instead of rewriting N into a full-blown block
4111 if not Scope_Is_Transient
4112 and then Is_Empty_List (Declarations (Blk))
4114 Insert_List_After (N, Statements (HSS));
4115 Rewrite (N, Make_Null_Statement (Loc));
4119 end Rewrite_Procedure_Call;
4121 -------------------------
4122 -- Formal_Is_Used_Once --
4123 -------------------------
4125 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is
4126 Use_Counter : Int := 0;
4128 function Count_Uses (N : Node_Id) return Traverse_Result;
4129 -- Traverse the tree and count the uses of the formal parameter.
4130 -- In this case, for optimization purposes, we do not need to
4131 -- continue the traversal once more than one use is encountered.
4137 function Count_Uses (N : Node_Id) return Traverse_Result is
4139 -- The original node is an identifier
4141 if Nkind (N) = N_Identifier
4142 and then Present (Entity (N))
4144 -- Original node's entity points to the one in the copied body
4146 and then Nkind (Entity (N)) = N_Identifier
4147 and then Present (Entity (Entity (N)))
4149 -- The entity of the copied node is the formal parameter
4151 and then Entity (Entity (N)) = Formal
4153 Use_Counter := Use_Counter + 1;
4155 if Use_Counter > 1 then
4157 -- Denote more than one use and abandon the traversal
4168 procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses);
4170 -- Start of processing for Formal_Is_Used_Once
4173 Count_Formal_Uses (Orig_Bod);
4174 return Use_Counter = 1;
4175 end Formal_Is_Used_Once;
4177 -- Start of processing for Expand_Inlined_Call
4180 -- Check for an illegal attempt to inline a recursive procedure. If the
4181 -- subprogram has parameters this is detected when trying to supply a
4182 -- binding for parameters that already have one. For parameterless
4183 -- subprograms this must be done explicitly.
4185 if In_Open_Scopes (Subp) then
4186 Error_Msg_N ("call to recursive subprogram cannot be inlined?", N);
4187 Set_Is_Inlined (Subp, False);
4191 if Nkind (Orig_Bod) = N_Defining_Identifier
4192 or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol
4194 -- Subprogram is renaming_as_body. Calls occurring after the renaming
4195 -- can be replaced with calls to the renamed entity directly, because
4196 -- the subprograms are subtype conformant. If the renamed subprogram
4197 -- is an inherited operation, we must redo the expansion because
4198 -- implicit conversions may be needed. Similarly, if the renamed
4199 -- entity is inlined, expand the call for further optimizations.
4201 Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc));
4203 if Present (Alias (Orig_Bod)) or else Is_Inlined (Orig_Bod) then
4210 -- Use generic machinery to copy body of inlined subprogram, as if it
4211 -- were an instantiation, resetting source locations appropriately, so
4212 -- that nested inlined calls appear in the main unit.
4214 Save_Env (Subp, Empty);
4215 Set_Copied_Sloc_For_Inlined_Body (N, Defining_Entity (Orig_Bod));
4217 Bod := Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True);
4219 Make_Block_Statement (Loc,
4220 Declarations => Declarations (Bod),
4221 Handled_Statement_Sequence => Handled_Statement_Sequence (Bod));
4223 if No (Declarations (Bod)) then
4224 Set_Declarations (Blk, New_List);
4227 -- For the unconstrained case, capture the name of the local variable
4228 -- that holds the result. This must be the first declaration in the
4229 -- block, because its bounds cannot depend on local variables. Otherwise
4230 -- there is no way to declare the result outside of the block. Needless
4231 -- to say, in general the bounds will depend on the actuals in the call.
4233 -- If the context is an assignment statement, as is the case for the
4234 -- expansion of an extended return, the left-hand side provides bounds
4235 -- even if the return type is unconstrained.
4238 if Nkind (Parent (N)) /= N_Assignment_Statement then
4239 Targ1 := Defining_Identifier (First (Declarations (Blk)));
4241 Targ1 := Name (Parent (N));
4245 -- If this is a derived function, establish the proper return type
4247 if Present (Orig_Subp) and then Orig_Subp /= Subp then
4248 Ret_Type := Etype (Orig_Subp);
4250 Ret_Type := Etype (Subp);
4253 -- Create temporaries for the actuals that are expressions, or that
4254 -- are scalars and require copying to preserve semantics.
4256 F := First_Formal (Subp);
4257 A := First_Actual (N);
4258 while Present (F) loop
4259 if Present (Renamed_Object (F)) then
4260 Error_Msg_N ("cannot inline call to recursive subprogram", N);
4264 -- If the argument may be a controlling argument in a call within
4265 -- the inlined body, we must preserve its classwide nature to insure
4266 -- that dynamic dispatching take place subsequently. If the formal
4267 -- has a constraint it must be preserved to retain the semantics of
4270 if Is_Class_Wide_Type (Etype (F))
4271 or else (Is_Access_Type (Etype (F))
4272 and then Is_Class_Wide_Type (Designated_Type (Etype (F))))
4274 Temp_Typ := Etype (F);
4276 elsif Base_Type (Etype (F)) = Base_Type (Etype (A))
4277 and then Etype (F) /= Base_Type (Etype (F))
4279 Temp_Typ := Etype (F);
4281 Temp_Typ := Etype (A);
4284 -- If the actual is a simple name or a literal, no need to
4285 -- create a temporary, object can be used directly.
4287 -- If the actual is a literal and the formal has its address taken,
4288 -- we cannot pass the literal itself as an argument, so its value
4289 -- must be captured in a temporary.
4291 if (Is_Entity_Name (A)
4293 (not Is_Scalar_Type (Etype (A))
4294 or else Ekind (Entity (A)) = E_Enumeration_Literal))
4296 -- When the actual is an identifier and the corresponding formal
4297 -- is used only once in the original body, the formal can be
4298 -- substituted directly with the actual parameter.
4300 or else (Nkind (A) = N_Identifier
4301 and then Formal_Is_Used_Once (F))
4304 (Nkind_In (A, N_Real_Literal,
4306 N_Character_Literal)
4307 and then not Address_Taken (F))
4309 if Etype (F) /= Etype (A) then
4311 (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A)));
4313 Set_Renamed_Object (F, A);
4317 Temp := Make_Temporary (Loc, 'C');
4319 -- If the actual for an in/in-out parameter is a view conversion,
4320 -- make it into an unchecked conversion, given that an untagged
4321 -- type conversion is not a proper object for a renaming.
4323 -- In-out conversions that involve real conversions have already
4324 -- been transformed in Expand_Actuals.
4326 if Nkind (A) = N_Type_Conversion
4327 and then Ekind (F) /= E_In_Parameter
4330 Make_Unchecked_Type_Conversion (Loc,
4331 Subtype_Mark => New_Occurrence_Of (Etype (F), Loc),
4332 Expression => Relocate_Node (Expression (A)));
4334 elsif Etype (F) /= Etype (A) then
4335 New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A));
4336 Temp_Typ := Etype (F);
4339 New_A := Relocate_Node (A);
4342 Set_Sloc (New_A, Sloc (N));
4344 -- If the actual has a by-reference type, it cannot be copied, so
4345 -- its value is captured in a renaming declaration. Otherwise
4346 -- declare a local constant initialized with the actual.
4348 -- We also use a renaming declaration for expressions of an array
4349 -- type that is not bit-packed, both for efficiency reasons and to
4350 -- respect the semantics of the call: in most cases the original
4351 -- call will pass the parameter by reference, and thus the inlined
4352 -- code will have the same semantics.
4354 if Ekind (F) = E_In_Parameter
4355 and then not Is_By_Reference_Type (Etype (A))
4357 (not Is_Array_Type (Etype (A))
4358 or else not Is_Object_Reference (A)
4359 or else Is_Bit_Packed_Array (Etype (A)))
4362 Make_Object_Declaration (Loc,
4363 Defining_Identifier => Temp,
4364 Constant_Present => True,
4365 Object_Definition => New_Occurrence_Of (Temp_Typ, Loc),
4366 Expression => New_A);
4369 Make_Object_Renaming_Declaration (Loc,
4370 Defining_Identifier => Temp,
4371 Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc),
4375 Append (Decl, Decls);
4376 Set_Renamed_Object (F, Temp);
4383 -- Establish target of function call. If context is not assignment or
4384 -- declaration, create a temporary as a target. The declaration for the
4385 -- temporary may be subsequently optimized away if the body is a single
4386 -- expression, or if the left-hand side of the assignment is simple
4387 -- enough, i.e. an entity or an explicit dereference of one.
4389 if Ekind (Subp) = E_Function then
4390 if Nkind (Parent (N)) = N_Assignment_Statement
4391 and then Is_Entity_Name (Name (Parent (N)))
4393 Targ := Name (Parent (N));
4395 elsif Nkind (Parent (N)) = N_Assignment_Statement
4396 and then Nkind (Name (Parent (N))) = N_Explicit_Dereference
4397 and then Is_Entity_Name (Prefix (Name (Parent (N))))
4399 Targ := Name (Parent (N));
4401 elsif Nkind (Parent (N)) = N_Assignment_Statement
4402 and then Nkind (Name (Parent (N))) = N_Selected_Component
4403 and then Is_Entity_Name (Prefix (Name (Parent (N))))
4405 Targ := New_Copy_Tree (Name (Parent (N)));
4407 elsif Nkind (Parent (N)) = N_Object_Declaration
4408 and then Is_Limited_Type (Etype (Subp))
4410 Targ := Defining_Identifier (Parent (N));
4413 -- Replace call with temporary and create its declaration
4415 Temp := Make_Temporary (Loc, 'C');
4416 Set_Is_Internal (Temp);
4418 -- For the unconstrained case, the generated temporary has the
4419 -- same constrained declaration as the result variable. It may
4420 -- eventually be possible to remove that temporary and use the
4421 -- result variable directly.
4424 and then Nkind (Parent (N)) /= N_Assignment_Statement
4427 Make_Object_Declaration (Loc,
4428 Defining_Identifier => Temp,
4429 Object_Definition =>
4430 New_Copy_Tree (Object_Definition (Parent (Targ1))));
4432 Replace_Formals (Decl);
4436 Make_Object_Declaration (Loc,
4437 Defining_Identifier => Temp,
4438 Object_Definition => New_Occurrence_Of (Ret_Type, Loc));
4440 Set_Etype (Temp, Ret_Type);
4443 Set_No_Initialization (Decl);
4444 Append (Decl, Decls);
4445 Rewrite (N, New_Occurrence_Of (Temp, Loc));
4450 Insert_Actions (N, Decls);
4452 -- Traverse the tree and replace formals with actuals or their thunks.
4453 -- Attach block to tree before analysis and rewriting.
4455 Replace_Formals (Blk);
4456 Set_Parent (Blk, N);
4458 if not Comes_From_Source (Subp) or else Is_Predef then
4462 if Present (Exit_Lab) then
4464 -- If the body was a single expression, the single return statement
4465 -- and the corresponding label are useless.
4469 Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) =
4472 Remove (Last (Statements (Handled_Statement_Sequence (Blk))));
4474 Append (Lab_Decl, (Declarations (Blk)));
4475 Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk)));
4479 -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on
4480 -- conflicting private views that Gigi would ignore. If this is a
4481 -- predefined unit, analyze with checks off, as is done in the non-
4482 -- inlined run-time units.
4485 I_Flag : constant Boolean := In_Inlined_Body;
4488 In_Inlined_Body := True;
4492 Style : constant Boolean := Style_Check;
4494 Style_Check := False;
4495 Analyze (Blk, Suppress => All_Checks);
4496 Style_Check := Style;
4503 In_Inlined_Body := I_Flag;
4506 if Ekind (Subp) = E_Procedure then
4507 Rewrite_Procedure_Call (N, Blk);
4510 Rewrite_Function_Call (N, Blk);
4512 -- For the unconstrained case, the replacement of the call has been
4513 -- made prior to the complete analysis of the generated declarations.
4514 -- Propagate the proper type now.
4517 if Nkind (N) = N_Identifier then
4518 Set_Etype (N, Etype (Entity (N)));
4520 Set_Etype (N, Etype (Targ1));
4527 -- Cleanup mapping between formals and actuals for other expansions
4529 F := First_Formal (Subp);
4530 while Present (F) loop
4531 Set_Renamed_Object (F, Empty);
4534 end Expand_Inlined_Call;
4536 ----------------------------------------
4537 -- Expand_N_Extended_Return_Statement --
4538 ----------------------------------------
4540 -- If there is a Handled_Statement_Sequence, we rewrite this:
4542 -- return Result : T := <expression> do
4543 -- <handled_seq_of_stms>
4549 -- Result : T := <expression>;
4551 -- <handled_seq_of_stms>
4555 -- Otherwise (no Handled_Statement_Sequence), we rewrite this:
4557 -- return Result : T := <expression>;
4561 -- return <expression>;
4563 -- unless it's build-in-place or there's no <expression>, in which case
4567 -- Result : T := <expression>;
4572 -- Note that this case could have been written by the user as an extended
4573 -- return statement, or could have been transformed to this from a simple
4574 -- return statement.
4576 -- That is, we need to have a reified return object if there are statements
4577 -- (which might refer to it) or if we're doing build-in-place (so we can
4578 -- set its address to the final resting place or if there is no expression
4579 -- (in which case default initial values might need to be set).
4581 procedure Expand_N_Extended_Return_Statement (N : Node_Id) is
4582 Loc : constant Source_Ptr := Sloc (N);
4584 Par_Func : constant Entity_Id :=
4585 Return_Applies_To (Return_Statement_Entity (N));
4586 Result_Subt : constant Entity_Id := Etype (Par_Func);
4587 Ret_Obj_Id : constant Entity_Id :=
4588 First_Entity (Return_Statement_Entity (N));
4589 Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id);
4591 Is_Build_In_Place : constant Boolean :=
4592 Is_Build_In_Place_Function (Par_Func);
4597 Return_Stmt : Node_Id;
4600 function Build_Heap_Allocator
4601 (Temp_Id : Entity_Id;
4602 Temp_Typ : Entity_Id;
4603 Func_Id : Entity_Id;
4604 Ret_Typ : Entity_Id;
4605 Alloc_Expr : Node_Id) return Node_Id;
4606 -- Create the statements necessary to allocate a return object on the
4607 -- caller's master. The master is available through implicit parameter
4608 -- BIPfinalizationmaster.
4610 -- if BIPfinalizationmaster /= null then
4612 -- type Ptr_Typ is access Ret_Typ;
4613 -- for Ptr_Typ'Storage_Pool use
4614 -- Base_Pool (BIPfinalizationmaster.all).all;
4618 -- procedure Allocate (...) is
4620 -- System.Storage_Pools.Subpools.Allocate_Any (...);
4623 -- Local := <Alloc_Expr>;
4624 -- Temp_Id := Temp_Typ (Local);
4628 -- Temp_Id is the temporary which is used to reference the internally
4629 -- created object in all allocation forms. Temp_Typ is the type of the
4630 -- temporary. Func_Id is the enclosing function. Ret_Typ is the return
4631 -- type of Func_Id. Alloc_Expr is the actual allocator.
4633 function Move_Activation_Chain return Node_Id;
4634 -- Construct a call to System.Tasking.Stages.Move_Activation_Chain
4636 -- From current activation chain
4637 -- To activation chain passed in by the caller
4638 -- New_Master master passed in by the caller
4640 --------------------------
4641 -- Build_Heap_Allocator --
4642 --------------------------
4644 function Build_Heap_Allocator
4645 (Temp_Id : Entity_Id;
4646 Temp_Typ : Entity_Id;
4647 Func_Id : Entity_Id;
4648 Ret_Typ : Entity_Id;
4649 Alloc_Expr : Node_Id) return Node_Id
4652 pragma Assert (Is_Build_In_Place_Function (Func_Id));
4654 -- Processing for build-in-place object allocation. This is disabled
4655 -- on .NET/JVM because the targets do not support pools.
4657 if VM_Target = No_VM
4658 and then Needs_Finalization (Ret_Typ)
4661 Decls : constant List_Id := New_List;
4662 Fin_Mas_Id : constant Entity_Id :=
4663 Build_In_Place_Formal
4664 (Func_Id, BIP_Finalization_Master);
4665 Stmts : constant List_Id := New_List;
4666 Desig_Typ : Entity_Id;
4667 Local_Id : Entity_Id;
4668 Pool_Id : Entity_Id;
4669 Ptr_Typ : Entity_Id;
4673 -- Pool_Id renames Base_Pool (BIPfinalizationmaster.all).all;
4675 Pool_Id := Make_Temporary (Loc, 'P');
4678 Make_Object_Renaming_Declaration (Loc,
4679 Defining_Identifier => Pool_Id,
4681 New_Reference_To (RTE (RE_Root_Storage_Pool), Loc),
4683 Make_Explicit_Dereference (Loc,
4685 Make_Function_Call (Loc,
4687 New_Reference_To (RTE (RE_Base_Pool), Loc),
4688 Parameter_Associations => New_List (
4689 Make_Explicit_Dereference (Loc,
4691 New_Reference_To (Fin_Mas_Id, Loc)))))));
4693 -- Create an access type which uses the storage pool of the
4694 -- caller's master. This additional type is necessary because
4695 -- the finalization master cannot be associated with the type
4696 -- of the temporary. Otherwise the secondary stack allocation
4699 Desig_Typ := Ret_Typ;
4701 -- Ensure that the build-in-place machinery uses a fat pointer
4702 -- when allocating an unconstrained array on the heap. In this
4703 -- case the result object type is a constrained array type even
4704 -- though the function type is unconstrained.
4706 if Ekind (Desig_Typ) = E_Array_Subtype then
4707 Desig_Typ := Base_Type (Desig_Typ);
4711 -- type Ptr_Typ is access Desig_Typ;
4713 Ptr_Typ := Make_Temporary (Loc, 'P');
4716 Make_Full_Type_Declaration (Loc,
4717 Defining_Identifier => Ptr_Typ,
4719 Make_Access_To_Object_Definition (Loc,
4720 Subtype_Indication =>
4721 New_Reference_To (Desig_Typ, Loc))));
4723 -- Perform minor decoration in order to set the master and the
4724 -- storage pool attributes.
4726 Set_Ekind (Ptr_Typ, E_Access_Type);
4727 Set_Finalization_Master (Ptr_Typ, Fin_Mas_Id);
4728 Set_Associated_Storage_Pool (Ptr_Typ, Pool_Id);
4730 -- Create the temporary, generate:
4731 -- Local_Id : Ptr_Typ;
4733 Local_Id := Make_Temporary (Loc, 'T');
4736 Make_Object_Declaration (Loc,
4737 Defining_Identifier => Local_Id,
4738 Object_Definition =>
4739 New_Reference_To (Ptr_Typ, Loc)));
4741 -- Allocate the object, generate:
4742 -- Local_Id := <Alloc_Expr>;
4745 Make_Assignment_Statement (Loc,
4746 Name => New_Reference_To (Local_Id, Loc),
4747 Expression => Alloc_Expr));
4750 -- Temp_Id := Temp_Typ (Local_Id);
4753 Make_Assignment_Statement (Loc,
4754 Name => New_Reference_To (Temp_Id, Loc),
4756 Unchecked_Convert_To (Temp_Typ,
4757 New_Reference_To (Local_Id, Loc))));
4759 -- Wrap the allocation in a block. This is further conditioned
4760 -- by checking the caller finalization master at runtime. A
4761 -- null value indicates a non-existent master, most likely due
4762 -- to a Finalize_Storage_Only allocation.
4765 -- if BIPfinalizationmaster /= null then
4774 Make_If_Statement (Loc,
4777 Left_Opnd => New_Reference_To (Fin_Mas_Id, Loc),
4778 Right_Opnd => Make_Null (Loc)),
4780 Then_Statements => New_List (
4781 Make_Block_Statement (Loc,
4782 Declarations => Decls,
4783 Handled_Statement_Sequence =>
4784 Make_Handled_Sequence_Of_Statements (Loc,
4785 Statements => Stmts))));
4788 -- For all other cases, generate:
4789 -- Temp_Id := <Alloc_Expr>;
4793 Make_Assignment_Statement (Loc,
4794 Name => New_Reference_To (Temp_Id, Loc),
4795 Expression => Alloc_Expr);
4797 end Build_Heap_Allocator;
4799 ---------------------------
4800 -- Move_Activation_Chain --
4801 ---------------------------
4803 function Move_Activation_Chain return Node_Id is
4806 Make_Procedure_Call_Statement (Loc,
4808 New_Reference_To (RTE (RE_Move_Activation_Chain), Loc),
4810 Parameter_Associations => New_List (
4814 Make_Attribute_Reference (Loc,
4815 Prefix => Make_Identifier (Loc, Name_uChain),
4816 Attribute_Name => Name_Unrestricted_Access),
4818 -- Destination chain
4821 (Build_In_Place_Formal (Par_Func, BIP_Activation_Chain), Loc),
4826 (Build_In_Place_Formal (Par_Func, BIP_Task_Master), Loc)));
4827 end Move_Activation_Chain;
4829 -- Start of processing for Expand_N_Extended_Return_Statement
4832 if Nkind (Ret_Obj_Decl) = N_Object_Declaration then
4833 Exp := Expression (Ret_Obj_Decl);
4838 HSS := Handled_Statement_Sequence (N);
4840 -- If the returned object needs finalization actions, the function must
4841 -- perform the appropriate cleanup should it fail to return. The state
4842 -- of the function itself is tracked through a flag which is coupled
4843 -- with the scope finalizer. There is one flag per each return object
4844 -- in case of multiple returns.
4846 if Is_Build_In_Place
4847 and then Needs_Finalization (Etype (Ret_Obj_Id))
4850 Flag_Decl : Node_Id;
4851 Flag_Id : Entity_Id;
4855 -- Recover the function body
4857 Func_Bod := Unit_Declaration_Node (Par_Func);
4859 if Nkind (Func_Bod) = N_Subprogram_Declaration then
4860 Func_Bod := Parent (Parent (Corresponding_Body (Func_Bod)));
4863 -- Create a flag to track the function state
4865 Flag_Id := Make_Temporary (Loc, 'F');
4866 Set_Return_Flag_Or_Transient_Decl (Ret_Obj_Id, Flag_Id);
4868 -- Insert the flag at the beginning of the function declarations,
4870 -- Fnn : Boolean := False;
4873 Make_Object_Declaration (Loc,
4874 Defining_Identifier => Flag_Id,
4875 Object_Definition =>
4876 New_Reference_To (Standard_Boolean, Loc),
4877 Expression => New_Reference_To (Standard_False, Loc));
4879 Prepend_To (Declarations (Func_Bod), Flag_Decl);
4880 Analyze (Flag_Decl);
4884 -- Build a simple_return_statement that returns the return object when
4885 -- there is a statement sequence, or no expression, or the result will
4886 -- be built in place. Note however that we currently do this for all
4887 -- composite cases, even though nonlimited composite results are not yet
4888 -- built in place (though we plan to do so eventually).
4891 or else Is_Composite_Type (Result_Subt)
4897 -- If the extended return has a handled statement sequence, then wrap
4898 -- it in a block and use the block as the first statement.
4902 Make_Block_Statement (Loc,
4903 Declarations => New_List,
4904 Handled_Statement_Sequence => HSS));
4907 -- If the result type contains tasks, we call Move_Activation_Chain.
4908 -- Later, the cleanup code will call Complete_Master, which will
4909 -- terminate any unactivated tasks belonging to the return statement
4910 -- master. But Move_Activation_Chain updates their master to be that
4911 -- of the caller, so they will not be terminated unless the return
4912 -- statement completes unsuccessfully due to exception, abort, goto,
4913 -- or exit. As a formality, we test whether the function requires the
4914 -- result to be built in place, though that's necessarily true for
4915 -- the case of result types with task parts.
4917 if Is_Build_In_Place
4918 and then Has_Task (Result_Subt)
4920 -- The return expression is an aggregate for a complex type which
4921 -- contains tasks. This particular case is left unexpanded since
4922 -- the regular expansion would insert all temporaries and
4923 -- initialization code in the wrong block.
4925 if Nkind (Exp) = N_Aggregate then
4926 Expand_N_Aggregate (Exp);
4929 -- Do not move the activation chain if the return object does not
4932 if Has_Task (Etype (Ret_Obj_Id)) then
4933 Append_To (Stmts, Move_Activation_Chain);
4937 -- Update the state of the function right before the object is
4940 if Is_Build_In_Place
4941 and then Needs_Finalization (Etype (Ret_Obj_Id))
4944 Flag_Id : constant Entity_Id :=
4945 Return_Flag_Or_Transient_Decl (Ret_Obj_Id);
4952 Make_Assignment_Statement (Loc,
4953 Name => New_Reference_To (Flag_Id, Loc),
4954 Expression => New_Reference_To (Standard_True, Loc)));
4958 -- Build a simple_return_statement that returns the return object
4961 Make_Simple_Return_Statement (Loc,
4962 Expression => New_Occurrence_Of (Ret_Obj_Id, Loc));
4963 Append_To (Stmts, Return_Stmt);
4965 HSS := Make_Handled_Sequence_Of_Statements (Loc, Stmts);
4968 -- Case where we build a return statement block
4970 if Present (HSS) then
4972 Make_Block_Statement (Loc,
4973 Declarations => Return_Object_Declarations (N),
4974 Handled_Statement_Sequence => HSS);
4976 -- We set the entity of the new block statement to be that of the
4977 -- return statement. This is necessary so that various fields, such
4978 -- as Finalization_Chain_Entity carry over from the return statement
4979 -- to the block. Note that this block is unusual, in that its entity
4980 -- is an E_Return_Statement rather than an E_Block.
4983 (Result, New_Occurrence_Of (Return_Statement_Entity (N), Loc));
4985 -- If the object decl was already rewritten as a renaming, then we
4986 -- don't want to do the object allocation and transformation of of
4987 -- the return object declaration to a renaming. This case occurs
4988 -- when the return object is initialized by a call to another
4989 -- build-in-place function, and that function is responsible for
4990 -- the allocation of the return object.
4992 if Is_Build_In_Place
4993 and then Nkind (Ret_Obj_Decl) = N_Object_Renaming_Declaration
4996 (Nkind (Original_Node (Ret_Obj_Decl)) = N_Object_Declaration
4997 and then Is_Build_In_Place_Function_Call
4998 (Expression (Original_Node (Ret_Obj_Decl))));
5000 -- Return the build-in-place result by reference
5002 Set_By_Ref (Return_Stmt);
5004 elsif Is_Build_In_Place then
5006 -- Locate the implicit access parameter associated with the
5007 -- caller-supplied return object and convert the return
5008 -- statement's return object declaration to a renaming of a
5009 -- dereference of the access parameter. If the return object's
5010 -- declaration includes an expression that has not already been
5011 -- expanded as separate assignments, then add an assignment
5012 -- statement to ensure the return object gets initialized.
5015 -- Result : T [:= <expression>];
5022 -- Result : T renames FuncRA.all;
5023 -- [Result := <expression;]
5028 Return_Obj_Id : constant Entity_Id :=
5029 Defining_Identifier (Ret_Obj_Decl);
5030 Return_Obj_Typ : constant Entity_Id := Etype (Return_Obj_Id);
5031 Return_Obj_Expr : constant Node_Id :=
5032 Expression (Ret_Obj_Decl);
5033 Constr_Result : constant Boolean :=
5034 Is_Constrained (Result_Subt);
5035 Obj_Alloc_Formal : Entity_Id;
5036 Object_Access : Entity_Id;
5037 Obj_Acc_Deref : Node_Id;
5038 Init_Assignment : Node_Id := Empty;
5041 -- Build-in-place results must be returned by reference
5043 Set_By_Ref (Return_Stmt);
5045 -- Retrieve the implicit access parameter passed by the caller
5048 Build_In_Place_Formal (Par_Func, BIP_Object_Access);
5050 -- If the return object's declaration includes an expression
5051 -- and the declaration isn't marked as No_Initialization, then
5052 -- we need to generate an assignment to the object and insert
5053 -- it after the declaration before rewriting it as a renaming
5054 -- (otherwise we'll lose the initialization). The case where
5055 -- the result type is an interface (or class-wide interface)
5056 -- is also excluded because the context of the function call
5057 -- must be unconstrained, so the initialization will always
5058 -- be done as part of an allocator evaluation (storage pool
5059 -- or secondary stack), never to a constrained target object
5060 -- passed in by the caller. Besides the assignment being
5061 -- unneeded in this case, it avoids problems with trying to
5062 -- generate a dispatching assignment when the return expression
5063 -- is a nonlimited descendant of a limited interface (the
5064 -- interface has no assignment operation).
5066 if Present (Return_Obj_Expr)
5067 and then not No_Initialization (Ret_Obj_Decl)
5068 and then not Is_Interface (Return_Obj_Typ)
5071 Make_Assignment_Statement (Loc,
5072 Name => New_Reference_To (Return_Obj_Id, Loc),
5073 Expression => Relocate_Node (Return_Obj_Expr));
5075 Set_Etype (Name (Init_Assignment), Etype (Return_Obj_Id));
5076 Set_Assignment_OK (Name (Init_Assignment));
5077 Set_No_Ctrl_Actions (Init_Assignment);
5079 Set_Parent (Name (Init_Assignment), Init_Assignment);
5080 Set_Parent (Expression (Init_Assignment), Init_Assignment);
5082 Set_Expression (Ret_Obj_Decl, Empty);
5084 if Is_Class_Wide_Type (Etype (Return_Obj_Id))
5085 and then not Is_Class_Wide_Type
5086 (Etype (Expression (Init_Assignment)))
5088 Rewrite (Expression (Init_Assignment),
5089 Make_Type_Conversion (Loc,
5091 New_Occurrence_Of (Etype (Return_Obj_Id), Loc),
5093 Relocate_Node (Expression (Init_Assignment))));
5096 -- In the case of functions where the calling context can
5097 -- determine the form of allocation needed, initialization
5098 -- is done with each part of the if statement that handles
5099 -- the different forms of allocation (this is true for
5100 -- unconstrained and tagged result subtypes).
5103 and then not Is_Tagged_Type (Underlying_Type (Result_Subt))
5105 Insert_After (Ret_Obj_Decl, Init_Assignment);
5109 -- When the function's subtype is unconstrained, a run-time
5110 -- test is needed to determine the form of allocation to use
5111 -- for the return object. The function has an implicit formal
5112 -- parameter indicating this. If the BIP_Alloc_Form formal has
5113 -- the value one, then the caller has passed access to an
5114 -- existing object for use as the return object. If the value
5115 -- is two, then the return object must be allocated on the
5116 -- secondary stack. Otherwise, the object must be allocated in
5117 -- a storage pool (currently only supported for the global
5118 -- heap, user-defined storage pools TBD ???). We generate an
5119 -- if statement to test the implicit allocation formal and
5120 -- initialize a local access value appropriately, creating
5121 -- allocators in the secondary stack and global heap cases.
5122 -- The special formal also exists and must be tested when the
5123 -- function has a tagged result, even when the result subtype
5124 -- is constrained, because in general such functions can be
5125 -- called in dispatching contexts and must be handled similarly
5126 -- to functions with a class-wide result.
5128 if not Constr_Result
5129 or else Is_Tagged_Type (Underlying_Type (Result_Subt))
5132 Build_In_Place_Formal (Par_Func, BIP_Alloc_Form);
5135 Pool_Id : constant Entity_Id :=
5136 Make_Temporary (Loc, 'P');
5137 Alloc_Obj_Id : Entity_Id;
5138 Alloc_Obj_Decl : Node_Id;
5139 Alloc_If_Stmt : Node_Id;
5140 Heap_Allocator : Node_Id;
5141 Pool_Decl : Node_Id;
5142 Pool_Allocator : Node_Id;
5143 Ptr_Type_Decl : Node_Id;
5144 Ref_Type : Entity_Id;
5145 SS_Allocator : Node_Id;
5148 -- Reuse the itype created for the function's implicit
5149 -- access formal. This avoids the need to create a new
5150 -- access type here, plus it allows assigning the access
5151 -- formal directly without applying a conversion.
5153 -- Ref_Type := Etype (Object_Access);
5155 -- Create an access type designating the function's
5158 Ref_Type := Make_Temporary (Loc, 'A');
5161 Make_Full_Type_Declaration (Loc,
5162 Defining_Identifier => Ref_Type,
5164 Make_Access_To_Object_Definition (Loc,
5165 All_Present => True,
5166 Subtype_Indication =>
5167 New_Reference_To (Return_Obj_Typ, Loc)));
5169 Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl);
5171 -- Create an access object that will be initialized to an
5172 -- access value denoting the return object, either coming
5173 -- from an implicit access value passed in by the caller
5174 -- or from the result of an allocator.
5176 Alloc_Obj_Id := Make_Temporary (Loc, 'R');
5177 Set_Etype (Alloc_Obj_Id, Ref_Type);
5180 Make_Object_Declaration (Loc,
5181 Defining_Identifier => Alloc_Obj_Id,
5182 Object_Definition =>
5183 New_Reference_To (Ref_Type, Loc));
5185 Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl);
5187 -- Create allocators for both the secondary stack and
5188 -- global heap. If there's an initialization expression,
5189 -- then create these as initialized allocators.
5191 if Present (Return_Obj_Expr)
5192 and then not No_Initialization (Ret_Obj_Decl)
5194 -- Always use the type of the expression for the
5195 -- qualified expression, rather than the result type.
5196 -- In general we cannot always use the result type
5197 -- for the allocator, because the expression might be
5198 -- of a specific type, such as in the case of an
5199 -- aggregate or even a nonlimited object when the
5200 -- result type is a limited class-wide interface type.
5203 Make_Allocator (Loc,
5205 Make_Qualified_Expression (Loc,
5208 (Etype (Return_Obj_Expr), Loc),
5210 New_Copy_Tree (Return_Obj_Expr)));
5213 -- If the function returns a class-wide type we cannot
5214 -- use the return type for the allocator. Instead we
5215 -- use the type of the expression, which must be an
5216 -- aggregate of a definite type.
5218 if Is_Class_Wide_Type (Return_Obj_Typ) then
5220 Make_Allocator (Loc,
5223 (Etype (Return_Obj_Expr), Loc));
5226 Make_Allocator (Loc,
5228 New_Reference_To (Return_Obj_Typ, Loc));
5231 -- If the object requires default initialization then
5232 -- that will happen later following the elaboration of
5233 -- the object renaming. If we don't turn it off here
5234 -- then the object will be default initialized twice.
5236 Set_No_Initialization (Heap_Allocator);
5239 -- The Pool_Allocator is just like the Heap_Allocator,
5240 -- except we set Storage_Pool and Procedure_To_Call so
5241 -- it will use the user-defined storage pool.
5243 Pool_Allocator := New_Copy_Tree (Heap_Allocator);
5245 -- Do not generate the renaming of the build-in-place
5246 -- pool parameter on .NET/JVM/ZFP because the parameter
5247 -- is not created in the first place.
5249 if VM_Target = No_VM
5250 and then RTE_Available (RE_Root_Storage_Pool_Ptr)
5253 Make_Object_Renaming_Declaration (Loc,
5254 Defining_Identifier => Pool_Id,
5257 (RTE (RE_Root_Storage_Pool), Loc),
5259 Make_Explicit_Dereference (Loc,
5261 (Build_In_Place_Formal
5262 (Par_Func, BIP_Storage_Pool), Loc)));
5263 Set_Storage_Pool (Pool_Allocator, Pool_Id);
5264 Set_Procedure_To_Call
5265 (Pool_Allocator, RTE (RE_Allocate_Any));
5267 Pool_Decl := Make_Null_Statement (Loc);
5270 -- If the No_Allocators restriction is active, then only
5271 -- an allocator for secondary stack allocation is needed.
5272 -- It's OK for such allocators to have Comes_From_Source
5273 -- set to False, because gigi knows not to flag them as
5274 -- being a violation of No_Implicit_Heap_Allocations.
5276 if Restriction_Active (No_Allocators) then
5277 SS_Allocator := Heap_Allocator;
5278 Heap_Allocator := Make_Null (Loc);
5279 Pool_Allocator := Make_Null (Loc);
5281 -- Otherwise the heap and pool allocators may be needed,
5282 -- so we make another allocator for secondary stack
5286 SS_Allocator := New_Copy_Tree (Heap_Allocator);
5288 -- The heap and pool allocators are marked as
5289 -- Comes_From_Source since they correspond to an
5290 -- explicit user-written allocator (that is, it will
5291 -- only be executed on behalf of callers that call the
5292 -- function as initialization for such an allocator).
5293 -- Prevents errors when No_Implicit_Heap_Allocations
5296 Set_Comes_From_Source (Heap_Allocator, True);
5297 Set_Comes_From_Source (Pool_Allocator, True);
5300 -- The allocator is returned on the secondary stack. We
5301 -- don't do this on VM targets, since the SS is not used.
5303 if VM_Target = No_VM then
5304 Set_Storage_Pool (SS_Allocator, RTE (RE_SS_Pool));
5305 Set_Procedure_To_Call
5306 (SS_Allocator, RTE (RE_SS_Allocate));
5308 -- The allocator is returned on the secondary stack,
5309 -- so indicate that the function return, as well as
5310 -- the block that encloses the allocator, must not
5311 -- release it. The flags must be set now because
5312 -- the decision to use the secondary stack is done
5313 -- very late in the course of expanding the return
5314 -- statement, past the point where these flags are
5317 Set_Sec_Stack_Needed_For_Return (Par_Func);
5318 Set_Sec_Stack_Needed_For_Return
5319 (Return_Statement_Entity (N));
5320 Set_Uses_Sec_Stack (Par_Func);
5321 Set_Uses_Sec_Stack (Return_Statement_Entity (N));
5324 -- Create an if statement to test the BIP_Alloc_Form
5325 -- formal and initialize the access object to either the
5326 -- BIP_Object_Access formal (BIP_Alloc_Form =
5327 -- Caller_Allocation), the result of allocating the
5328 -- object in the secondary stack (BIP_Alloc_Form =
5329 -- Secondary_Stack), or else an allocator to create the
5330 -- return object in the heap or user-defined pool
5331 -- (BIP_Alloc_Form = Global_Heap or User_Storage_Pool).
5333 -- ??? An unchecked type conversion must be made in the
5334 -- case of assigning the access object formal to the
5335 -- local access object, because a normal conversion would
5336 -- be illegal in some cases (such as converting access-
5337 -- to-unconstrained to access-to-constrained), but the
5338 -- the unchecked conversion will presumably fail to work
5339 -- right in just such cases. It's not clear at all how to
5343 Make_If_Statement (Loc,
5347 New_Reference_To (Obj_Alloc_Formal, Loc),
5349 Make_Integer_Literal (Loc,
5350 UI_From_Int (BIP_Allocation_Form'Pos
5351 (Caller_Allocation)))),
5353 Then_Statements => New_List (
5354 Make_Assignment_Statement (Loc,
5356 New_Reference_To (Alloc_Obj_Id, Loc),
5358 Make_Unchecked_Type_Conversion (Loc,
5360 New_Reference_To (Ref_Type, Loc),
5362 New_Reference_To (Object_Access, Loc)))),
5364 Elsif_Parts => New_List (
5365 Make_Elsif_Part (Loc,
5369 New_Reference_To (Obj_Alloc_Formal, Loc),
5371 Make_Integer_Literal (Loc,
5372 UI_From_Int (BIP_Allocation_Form'Pos
5373 (Secondary_Stack)))),
5375 Then_Statements => New_List (
5376 Make_Assignment_Statement (Loc,
5378 New_Reference_To (Alloc_Obj_Id, Loc),
5379 Expression => SS_Allocator))),
5381 Make_Elsif_Part (Loc,
5385 New_Reference_To (Obj_Alloc_Formal, Loc),
5387 Make_Integer_Literal (Loc,
5388 UI_From_Int (BIP_Allocation_Form'Pos
5391 Then_Statements => New_List (
5392 Build_Heap_Allocator
5393 (Temp_Id => Alloc_Obj_Id,
5394 Temp_Typ => Ref_Type,
5395 Func_Id => Par_Func,
5396 Ret_Typ => Return_Obj_Typ,
5397 Alloc_Expr => Heap_Allocator)))),
5399 Else_Statements => New_List (
5401 Build_Heap_Allocator
5402 (Temp_Id => Alloc_Obj_Id,
5403 Temp_Typ => Ref_Type,
5404 Func_Id => Par_Func,
5405 Ret_Typ => Return_Obj_Typ,
5406 Alloc_Expr => Pool_Allocator)));
5408 -- If a separate initialization assignment was created
5409 -- earlier, append that following the assignment of the
5410 -- implicit access formal to the access object, to ensure
5411 -- that the return object is initialized in that case. In
5412 -- this situation, the target of the assignment must be
5413 -- rewritten to denote a dereference of the access to the
5414 -- return object passed in by the caller.
5416 if Present (Init_Assignment) then
5417 Rewrite (Name (Init_Assignment),
5418 Make_Explicit_Dereference (Loc,
5419 Prefix => New_Reference_To (Alloc_Obj_Id, Loc)));
5422 (Name (Init_Assignment), Etype (Return_Obj_Id));
5425 (Then_Statements (Alloc_If_Stmt), Init_Assignment);
5428 Insert_Before (Ret_Obj_Decl, Alloc_If_Stmt);
5430 -- Remember the local access object for use in the
5431 -- dereference of the renaming created below.
5433 Object_Access := Alloc_Obj_Id;
5437 -- Replace the return object declaration with a renaming of a
5438 -- dereference of the access value designating the return
5442 Make_Explicit_Dereference (Loc,
5443 Prefix => New_Reference_To (Object_Access, Loc));
5445 Rewrite (Ret_Obj_Decl,
5446 Make_Object_Renaming_Declaration (Loc,
5447 Defining_Identifier => Return_Obj_Id,
5448 Access_Definition => Empty,
5450 New_Occurrence_Of (Return_Obj_Typ, Loc),
5451 Name => Obj_Acc_Deref));
5453 Set_Renamed_Object (Return_Obj_Id, Obj_Acc_Deref);
5457 -- Case where we do not build a block
5460 -- We're about to drop Return_Object_Declarations on the floor, so
5461 -- we need to insert it, in case it got expanded into useful code.
5462 -- Remove side effects from expression, which may be duplicated in
5463 -- subsequent checks (see Expand_Simple_Function_Return).
5465 Insert_List_Before (N, Return_Object_Declarations (N));
5466 Remove_Side_Effects (Exp);
5468 -- Build simple_return_statement that returns the expression directly
5470 Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => Exp);
5471 Result := Return_Stmt;
5474 -- Set the flag to prevent infinite recursion
5476 Set_Comes_From_Extended_Return_Statement (Return_Stmt);
5478 Rewrite (N, Result);
5480 end Expand_N_Extended_Return_Statement;
5482 ----------------------------
5483 -- Expand_N_Function_Call --
5484 ----------------------------
5486 procedure Expand_N_Function_Call (N : Node_Id) is
5490 -- If the return value of a foreign compiled function is VAX Float, then
5491 -- expand the return (adjusts the location of the return value on
5492 -- Alpha/VMS, no-op everywhere else).
5493 -- Comes_From_Source intercepts recursive expansion.
5495 if Vax_Float (Etype (N))
5496 and then Nkind (N) = N_Function_Call
5497 and then Present (Name (N))
5498 and then Present (Entity (Name (N)))
5499 and then Has_Foreign_Convention (Entity (Name (N)))
5500 and then Comes_From_Source (Parent (N))
5502 Expand_Vax_Foreign_Return (N);
5504 end Expand_N_Function_Call;
5506 ---------------------------------------
5507 -- Expand_N_Procedure_Call_Statement --
5508 ---------------------------------------
5510 procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is
5513 end Expand_N_Procedure_Call_Statement;
5515 --------------------------------------
5516 -- Expand_N_Simple_Return_Statement --
5517 --------------------------------------
5519 procedure Expand_N_Simple_Return_Statement (N : Node_Id) is
5521 -- Defend against previous errors (i.e. the return statement calls a
5522 -- function that is not available in configurable runtime).
5524 if Present (Expression (N))
5525 and then Nkind (Expression (N)) = N_Empty
5530 -- Distinguish the function and non-function cases:
5532 case Ekind (Return_Applies_To (Return_Statement_Entity (N))) is
5535 E_Generic_Function =>
5536 Expand_Simple_Function_Return (N);
5539 E_Generic_Procedure |
5542 E_Return_Statement =>
5543 Expand_Non_Function_Return (N);
5546 raise Program_Error;
5550 when RE_Not_Available =>
5552 end Expand_N_Simple_Return_Statement;
5554 ------------------------------
5555 -- Expand_N_Subprogram_Body --
5556 ------------------------------
5558 -- Add poll call if ATC polling is enabled, unless the body will be inlined
5561 -- Add dummy push/pop label nodes at start and end to clear any local
5562 -- exception indications if local-exception-to-goto optimization is active.
5564 -- Add return statement if last statement in body is not a return statement
5565 -- (this makes things easier on Gigi which does not want to have to handle
5566 -- a missing return).
5568 -- Add call to Activate_Tasks if body is a task activator
5570 -- Deal with possible detection of infinite recursion
5572 -- Eliminate body completely if convention stubbed
5574 -- Encode entity names within body, since we will not need to reference
5575 -- these entities any longer in the front end.
5577 -- Initialize scalar out parameters if Initialize/Normalize_Scalars
5579 -- Reset Pure indication if any parameter has root type System.Address
5580 -- or has any parameters of limited types, where limited means that the
5581 -- run-time view is limited (i.e. the full type is limited).
5585 procedure Expand_N_Subprogram_Body (N : Node_Id) is
5586 Loc : constant Source_Ptr := Sloc (N);
5587 H : constant Node_Id := Handled_Statement_Sequence (N);
5588 Body_Id : Entity_Id;
5591 Spec_Id : Entity_Id;
5593 procedure Add_Return (S : List_Id);
5594 -- Append a return statement to the statement sequence S if the last
5595 -- statement is not already a return or a goto statement. Note that
5596 -- the latter test is not critical, it does not matter if we add a few
5597 -- extra returns, since they get eliminated anyway later on.
5603 procedure Add_Return (S : List_Id) is
5608 -- Get last statement, ignoring any Pop_xxx_Label nodes, which are
5609 -- not relevant in this context since they are not executable.
5611 Last_Stm := Last (S);
5612 while Nkind (Last_Stm) in N_Pop_xxx_Label loop
5616 -- Now insert return unless last statement is a transfer
5618 if not Is_Transfer (Last_Stm) then
5620 -- The source location for the return is the end label of the
5621 -- procedure if present. Otherwise use the sloc of the last
5622 -- statement in the list. If the list comes from a generated
5623 -- exception handler and we are not debugging generated code,
5624 -- all the statements within the handler are made invisible
5627 if Nkind (Parent (S)) = N_Exception_Handler
5628 and then not Comes_From_Source (Parent (S))
5630 Loc := Sloc (Last_Stm);
5631 elsif Present (End_Label (H)) then
5632 Loc := Sloc (End_Label (H));
5634 Loc := Sloc (Last_Stm);
5638 Rtn : constant Node_Id := Make_Simple_Return_Statement (Loc);
5641 -- Append return statement, and set analyzed manually. We can't
5642 -- call Analyze on this return since the scope is wrong.
5644 -- Note: it almost works to push the scope and then do the
5645 -- Analyze call, but something goes wrong in some weird cases
5646 -- and it is not worth worrying about ???
5651 -- Call _Postconditions procedure if appropriate. We need to
5652 -- do this explicitly because we did not analyze the generated
5653 -- return statement above, so the call did not get inserted.
5655 if Ekind (Spec_Id) = E_Procedure
5656 and then Has_Postconditions (Spec_Id)
5658 pragma Assert (Present (Postcondition_Proc (Spec_Id)));
5660 Make_Procedure_Call_Statement (Loc,
5662 New_Reference_To (Postcondition_Proc (Spec_Id), Loc)));
5668 -- Start of processing for Expand_N_Subprogram_Body
5671 -- Set L to either the list of declarations if present, or to the list
5672 -- of statements if no declarations are present. This is used to insert
5673 -- new stuff at the start.
5675 if Is_Non_Empty_List (Declarations (N)) then
5676 L := Declarations (N);
5678 L := Statements (H);
5681 -- If local-exception-to-goto optimization active, insert dummy push
5682 -- statements at start, and dummy pop statements at end, but inhibit
5683 -- this if we have No_Exception_Handlers, since they are useless and
5684 -- intefere with analysis, e.g. by codepeer.
5686 if (Debug_Flag_Dot_G
5687 or else Restriction_Active (No_Exception_Propagation))
5688 and then not Restriction_Active (No_Exception_Handlers)
5689 and then not CodePeer_Mode
5690 and then Is_Non_Empty_List (L)
5693 FS : constant Node_Id := First (L);
5694 FL : constant Source_Ptr := Sloc (FS);
5699 -- LS points to either last statement, if statements are present
5700 -- or to the last declaration if there are no statements present.
5701 -- It is the node after which the pop's are generated.
5703 if Is_Non_Empty_List (Statements (H)) then
5704 LS := Last (Statements (H));
5711 Insert_List_Before_And_Analyze (FS, New_List (
5712 Make_Push_Constraint_Error_Label (FL),
5713 Make_Push_Program_Error_Label (FL),
5714 Make_Push_Storage_Error_Label (FL)));
5716 Insert_List_After_And_Analyze (LS, New_List (
5717 Make_Pop_Constraint_Error_Label (LL),
5718 Make_Pop_Program_Error_Label (LL),
5719 Make_Pop_Storage_Error_Label (LL)));
5723 -- Find entity for subprogram
5725 Body_Id := Defining_Entity (N);
5727 if Present (Corresponding_Spec (N)) then
5728 Spec_Id := Corresponding_Spec (N);
5733 -- Need poll on entry to subprogram if polling enabled. We only do this
5734 -- for non-empty subprograms, since it does not seem necessary to poll
5735 -- for a dummy null subprogram.
5737 if Is_Non_Empty_List (L) then
5739 -- Do not add a polling call if the subprogram is to be inlined by
5740 -- the back-end, to avoid repeated calls with multiple inlinings.
5742 if Is_Inlined (Spec_Id)
5743 and then Front_End_Inlining
5744 and then Optimization_Level > 1
5748 Generate_Poll_Call (First (L));
5752 -- If this is a Pure function which has any parameters whose root type
5753 -- is System.Address, reset the Pure indication, since it will likely
5754 -- cause incorrect code to be generated as the parameter is probably
5755 -- a pointer, and the fact that the same pointer is passed does not mean
5756 -- that the same value is being referenced.
5758 -- Note that if the programmer gave an explicit Pure_Function pragma,
5759 -- then we believe the programmer, and leave the subprogram Pure.
5761 -- This code should probably be at the freeze point, so that it happens
5762 -- even on a -gnatc (or more importantly -gnatt) compile, so that the
5763 -- semantic tree has Is_Pure set properly ???
5765 if Is_Pure (Spec_Id)
5766 and then Is_Subprogram (Spec_Id)
5767 and then not Has_Pragma_Pure_Function (Spec_Id)
5773 F := First_Formal (Spec_Id);
5774 while Present (F) loop
5775 if Is_Descendent_Of_Address (Etype (F))
5777 -- Note that this test is being made in the body of the
5778 -- subprogram, not the spec, so we are testing the full
5779 -- type for being limited here, as required.
5781 or else Is_Limited_Type (Etype (F))
5783 Set_Is_Pure (Spec_Id, False);
5785 if Spec_Id /= Body_Id then
5786 Set_Is_Pure (Body_Id, False);
5797 -- Initialize any scalar OUT args if Initialize/Normalize_Scalars
5799 if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then
5804 -- Loop through formals
5806 F := First_Formal (Spec_Id);
5807 while Present (F) loop
5808 if Is_Scalar_Type (Etype (F))
5809 and then Ekind (F) = E_Out_Parameter
5811 Check_Restriction (No_Default_Initialization, F);
5813 -- Insert the initialization. We turn off validity checks
5814 -- for this assignment, since we do not want any check on
5815 -- the initial value itself (which may well be invalid).
5817 Insert_Before_And_Analyze (First (L),
5818 Make_Assignment_Statement (Loc,
5819 Name => New_Occurrence_Of (F, Loc),
5820 Expression => Get_Simple_Init_Val (Etype (F), N)),
5821 Suppress => Validity_Check);
5829 -- Clear out statement list for stubbed procedure
5831 if Present (Corresponding_Spec (N)) then
5832 Set_Elaboration_Flag (N, Spec_Id);
5834 if Convention (Spec_Id) = Convention_Stubbed
5835 or else Is_Eliminated (Spec_Id)
5837 Set_Declarations (N, Empty_List);
5838 Set_Handled_Statement_Sequence (N,
5839 Make_Handled_Sequence_Of_Statements (Loc,
5840 Statements => New_List (Make_Null_Statement (Loc))));
5845 -- Create a set of discriminals for the next protected subprogram body
5847 if Is_List_Member (N)
5848 and then Present (Parent (List_Containing (N)))
5849 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
5850 and then Present (Next_Protected_Operation (N))
5852 Set_Discriminals (Parent (Base_Type (Scope (Spec_Id))));
5855 -- Returns_By_Ref flag is normally set when the subprogram is frozen but
5856 -- subprograms with no specs are not frozen.
5859 Typ : constant Entity_Id := Etype (Spec_Id);
5860 Utyp : constant Entity_Id := Underlying_Type (Typ);
5863 if not Acts_As_Spec (N)
5864 and then Nkind (Parent (Parent (Spec_Id))) /=
5865 N_Subprogram_Body_Stub
5869 elsif Is_Immutably_Limited_Type (Typ) then
5870 Set_Returns_By_Ref (Spec_Id);
5872 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
5873 Set_Returns_By_Ref (Spec_Id);
5877 -- For a procedure, we add a return for all possible syntactic ends of
5880 if Ekind_In (Spec_Id, E_Procedure, E_Generic_Procedure) then
5881 Add_Return (Statements (H));
5883 if Present (Exception_Handlers (H)) then
5884 Except_H := First_Non_Pragma (Exception_Handlers (H));
5885 while Present (Except_H) loop
5886 Add_Return (Statements (Except_H));
5887 Next_Non_Pragma (Except_H);
5891 -- For a function, we must deal with the case where there is at least
5892 -- one missing return. What we do is to wrap the entire body of the
5893 -- function in a block:
5906 -- raise Program_Error;
5909 -- This approach is necessary because the raise must be signalled to the
5910 -- caller, not handled by any local handler (RM 6.4(11)).
5912 -- Note: we do not need to analyze the constructed sequence here, since
5913 -- it has no handler, and an attempt to analyze the handled statement
5914 -- sequence twice is risky in various ways (e.g. the issue of expanding
5915 -- cleanup actions twice).
5917 elsif Has_Missing_Return (Spec_Id) then
5919 Hloc : constant Source_Ptr := Sloc (H);
5920 Blok : constant Node_Id :=
5921 Make_Block_Statement (Hloc,
5922 Handled_Statement_Sequence => H);
5923 Rais : constant Node_Id :=
5924 Make_Raise_Program_Error (Hloc,
5925 Reason => PE_Missing_Return);
5928 Set_Handled_Statement_Sequence (N,
5929 Make_Handled_Sequence_Of_Statements (Hloc,
5930 Statements => New_List (Blok, Rais)));
5932 Push_Scope (Spec_Id);
5939 -- If subprogram contains a parameterless recursive call, then we may
5940 -- have an infinite recursion, so see if we can generate code to check
5941 -- for this possibility if storage checks are not suppressed.
5943 if Ekind (Spec_Id) = E_Procedure
5944 and then Has_Recursive_Call (Spec_Id)
5945 and then not Storage_Checks_Suppressed (Spec_Id)
5947 Detect_Infinite_Recursion (N, Spec_Id);
5950 -- Set to encode entity names in package body before gigi is called
5952 Qualify_Entity_Names (N);
5953 end Expand_N_Subprogram_Body;
5955 -----------------------------------
5956 -- Expand_N_Subprogram_Body_Stub --
5957 -----------------------------------
5959 procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is
5961 if Present (Corresponding_Body (N)) then
5962 Expand_N_Subprogram_Body (
5963 Unit_Declaration_Node (Corresponding_Body (N)));
5965 end Expand_N_Subprogram_Body_Stub;
5967 -------------------------------------
5968 -- Expand_N_Subprogram_Declaration --
5969 -------------------------------------
5971 -- If the declaration appears within a protected body, it is a private
5972 -- operation of the protected type. We must create the corresponding
5973 -- protected subprogram an associated formals. For a normal protected
5974 -- operation, this is done when expanding the protected type declaration.
5976 -- If the declaration is for a null procedure, emit null body
5978 procedure Expand_N_Subprogram_Declaration (N : Node_Id) is
5979 Loc : constant Source_Ptr := Sloc (N);
5980 Subp : constant Entity_Id := Defining_Entity (N);
5981 Scop : constant Entity_Id := Scope (Subp);
5982 Prot_Decl : Node_Id;
5984 Prot_Id : Entity_Id;
5987 -- In SPARK, subprogram declarations are only allowed in package
5990 if Nkind (Parent (N)) /= N_Package_Specification then
5991 if Nkind (Parent (N)) = N_Compilation_Unit then
5992 Check_SPARK_Restriction
5993 ("subprogram declaration is not a library item", N);
5995 elsif Present (Next (N))
5996 and then Nkind (Next (N)) = N_Pragma
5997 and then Get_Pragma_Id (Pragma_Name (Next (N))) = Pragma_Import
5999 -- In SPARK, subprogram declarations are also permitted in
6000 -- declarative parts when immediately followed by a corresponding
6001 -- pragma Import. We only check here that there is some pragma
6006 Check_SPARK_Restriction
6007 ("subprogram declaration is not allowed here", N);
6011 -- Deal with case of protected subprogram. Do not generate protected
6012 -- operation if operation is flagged as eliminated.
6014 if Is_List_Member (N)
6015 and then Present (Parent (List_Containing (N)))
6016 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
6017 and then Is_Protected_Type (Scop)
6019 if No (Protected_Body_Subprogram (Subp))
6020 and then not Is_Eliminated (Subp)
6023 Make_Subprogram_Declaration (Loc,
6025 Build_Protected_Sub_Specification
6026 (N, Scop, Unprotected_Mode));
6028 -- The protected subprogram is declared outside of the protected
6029 -- body. Given that the body has frozen all entities so far, we
6030 -- analyze the subprogram and perform freezing actions explicitly.
6031 -- including the generation of an explicit freeze node, to ensure
6032 -- that gigi has the proper order of elaboration.
6033 -- If the body is a subunit, the insertion point is before the
6034 -- stub in the parent.
6036 Prot_Bod := Parent (List_Containing (N));
6038 if Nkind (Parent (Prot_Bod)) = N_Subunit then
6039 Prot_Bod := Corresponding_Stub (Parent (Prot_Bod));
6042 Insert_Before (Prot_Bod, Prot_Decl);
6043 Prot_Id := Defining_Unit_Name (Specification (Prot_Decl));
6044 Set_Has_Delayed_Freeze (Prot_Id);
6046 Push_Scope (Scope (Scop));
6047 Analyze (Prot_Decl);
6048 Freeze_Before (N, Prot_Id);
6049 Set_Protected_Body_Subprogram (Subp, Prot_Id);
6051 -- Create protected operation as well. Even though the operation
6052 -- is only accessible within the body, it is possible to make it
6053 -- available outside of the protected object by using 'Access to
6054 -- provide a callback, so build protected version in all cases.
6057 Make_Subprogram_Declaration (Loc,
6059 Build_Protected_Sub_Specification (N, Scop, Protected_Mode));
6060 Insert_Before (Prot_Bod, Prot_Decl);
6061 Analyze (Prot_Decl);
6066 -- Ada 2005 (AI-348): Generate body for a null procedure. In most
6067 -- cases this is superfluous because calls to it will be automatically
6068 -- inlined, but we definitely need the body if preconditions for the
6069 -- procedure are present.
6071 elsif Nkind (Specification (N)) = N_Procedure_Specification
6072 and then Null_Present (Specification (N))
6075 Bod : constant Node_Id := Body_To_Inline (N);
6078 Set_Has_Completion (Subp, False);
6079 Append_Freeze_Action (Subp, Bod);
6081 -- The body now contains raise statements, so calls to it will
6084 Set_Is_Inlined (Subp, False);
6087 end Expand_N_Subprogram_Declaration;
6089 --------------------------------
6090 -- Expand_Non_Function_Return --
6091 --------------------------------
6093 procedure Expand_Non_Function_Return (N : Node_Id) is
6094 pragma Assert (No (Expression (N)));
6096 Loc : constant Source_Ptr := Sloc (N);
6097 Scope_Id : Entity_Id :=
6098 Return_Applies_To (Return_Statement_Entity (N));
6099 Kind : constant Entity_Kind := Ekind (Scope_Id);
6102 Goto_Stat : Node_Id;
6106 -- Call _Postconditions procedure if procedure with active
6107 -- postconditions. Here, we use the Postcondition_Proc attribute,
6108 -- which is needed for implicitly-generated returns. Functions
6109 -- never have implicitly-generated returns, and there's no
6110 -- room for Postcondition_Proc in E_Function, so we look up the
6111 -- identifier Name_uPostconditions for function returns (see
6112 -- Expand_Simple_Function_Return).
6114 if Ekind (Scope_Id) = E_Procedure
6115 and then Has_Postconditions (Scope_Id)
6117 pragma Assert (Present (Postcondition_Proc (Scope_Id)));
6119 Make_Procedure_Call_Statement (Loc,
6120 Name => New_Reference_To (Postcondition_Proc (Scope_Id), Loc)));
6123 -- If it is a return from a procedure do no extra steps
6125 if Kind = E_Procedure or else Kind = E_Generic_Procedure then
6128 -- If it is a nested return within an extended one, replace it with a
6129 -- return of the previously declared return object.
6131 elsif Kind = E_Return_Statement then
6133 Make_Simple_Return_Statement (Loc,
6135 New_Occurrence_Of (First_Entity (Scope_Id), Loc)));
6136 Set_Comes_From_Extended_Return_Statement (N);
6137 Set_Return_Statement_Entity (N, Scope_Id);
6138 Expand_Simple_Function_Return (N);
6142 pragma Assert (Is_Entry (Scope_Id));
6144 -- Look at the enclosing block to see whether the return is from an
6145 -- accept statement or an entry body.
6147 for J in reverse 0 .. Scope_Stack.Last loop
6148 Scope_Id := Scope_Stack.Table (J).Entity;
6149 exit when Is_Concurrent_Type (Scope_Id);
6152 -- If it is a return from accept statement it is expanded as call to
6153 -- RTS Complete_Rendezvous and a goto to the end of the accept body.
6155 -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept,
6156 -- Expand_N_Accept_Alternative in exp_ch9.adb)
6158 if Is_Task_Type (Scope_Id) then
6161 Make_Procedure_Call_Statement (Loc,
6162 Name => New_Reference_To (RTE (RE_Complete_Rendezvous), Loc));
6163 Insert_Before (N, Call);
6164 -- why not insert actions here???
6167 Acc_Stat := Parent (N);
6168 while Nkind (Acc_Stat) /= N_Accept_Statement loop
6169 Acc_Stat := Parent (Acc_Stat);
6172 Lab_Node := Last (Statements
6173 (Handled_Statement_Sequence (Acc_Stat)));
6175 Goto_Stat := Make_Goto_Statement (Loc,
6176 Name => New_Occurrence_Of
6177 (Entity (Identifier (Lab_Node)), Loc));
6179 Set_Analyzed (Goto_Stat);
6181 Rewrite (N, Goto_Stat);
6184 -- If it is a return from an entry body, put a Complete_Entry_Body call
6185 -- in front of the return.
6187 elsif Is_Protected_Type (Scope_Id) then
6189 Make_Procedure_Call_Statement (Loc,
6191 New_Reference_To (RTE (RE_Complete_Entry_Body), Loc),
6192 Parameter_Associations => New_List (
6193 Make_Attribute_Reference (Loc,
6196 (Find_Protection_Object (Current_Scope), Loc),
6197 Attribute_Name => Name_Unchecked_Access)));
6199 Insert_Before (N, Call);
6202 end Expand_Non_Function_Return;
6204 ---------------------------------------
6205 -- Expand_Protected_Object_Reference --
6206 ---------------------------------------
6208 function Expand_Protected_Object_Reference
6210 Scop : Entity_Id) return Node_Id
6212 Loc : constant Source_Ptr := Sloc (N);
6219 Rec := Make_Identifier (Loc, Name_uObject);
6220 Set_Etype (Rec, Corresponding_Record_Type (Scop));
6222 -- Find enclosing protected operation, and retrieve its first parameter,
6223 -- which denotes the enclosing protected object. If the enclosing
6224 -- operation is an entry, we are immediately within the protected body,
6225 -- and we can retrieve the object from the service entries procedure. A
6226 -- barrier function has the same signature as an entry. A barrier
6227 -- function is compiled within the protected object, but unlike
6228 -- protected operations its never needs locks, so that its protected
6229 -- body subprogram points to itself.
6231 Proc := Current_Scope;
6232 while Present (Proc)
6233 and then Scope (Proc) /= Scop
6235 Proc := Scope (Proc);
6238 Corr := Protected_Body_Subprogram (Proc);
6242 -- Previous error left expansion incomplete.
6243 -- Nothing to do on this call.
6250 (First (Parameter_Specifications (Parent (Corr))));
6252 if Is_Subprogram (Proc)
6253 and then Proc /= Corr
6255 -- Protected function or procedure
6257 Set_Entity (Rec, Param);
6259 -- Rec is a reference to an entity which will not be in scope when
6260 -- the call is reanalyzed, and needs no further analysis.
6265 -- Entry or barrier function for entry body. The first parameter of
6266 -- the entry body procedure is pointer to the object. We create a
6267 -- local variable of the proper type, duplicating what is done to
6268 -- define _object later on.
6272 Obj_Ptr : constant Entity_Id := Make_Temporary (Loc, 'T');
6276 Make_Full_Type_Declaration (Loc,
6277 Defining_Identifier => Obj_Ptr,
6279 Make_Access_To_Object_Definition (Loc,
6280 Subtype_Indication =>
6282 (Corresponding_Record_Type (Scop), Loc))));
6284 Insert_Actions (N, Decls);
6285 Freeze_Before (N, Obj_Ptr);
6288 Make_Explicit_Dereference (Loc,
6290 Unchecked_Convert_To (Obj_Ptr,
6291 New_Occurrence_Of (Param, Loc)));
6293 -- Analyze new actual. Other actuals in calls are already analyzed
6294 -- and the list of actuals is not reanalyzed after rewriting.
6296 Set_Parent (Rec, N);
6302 end Expand_Protected_Object_Reference;
6304 --------------------------------------
6305 -- Expand_Protected_Subprogram_Call --
6306 --------------------------------------
6308 procedure Expand_Protected_Subprogram_Call
6316 -- If the protected object is not an enclosing scope, this is an inter-
6317 -- object function call. Inter-object procedure calls are expanded by
6318 -- Exp_Ch9.Build_Simple_Entry_Call. The call is intra-object only if the
6319 -- subprogram being called is in the protected body being compiled, and
6320 -- if the protected object in the call is statically the enclosing type.
6321 -- The object may be an component of some other data structure, in which
6322 -- case this must be handled as an inter-object call.
6324 if not In_Open_Scopes (Scop)
6325 or else not Is_Entity_Name (Name (N))
6327 if Nkind (Name (N)) = N_Selected_Component then
6328 Rec := Prefix (Name (N));
6331 pragma Assert (Nkind (Name (N)) = N_Indexed_Component);
6332 Rec := Prefix (Prefix (Name (N)));
6335 Build_Protected_Subprogram_Call (N,
6336 Name => New_Occurrence_Of (Subp, Sloc (N)),
6337 Rec => Convert_Concurrent (Rec, Etype (Rec)),
6341 Rec := Expand_Protected_Object_Reference (N, Scop);
6347 Build_Protected_Subprogram_Call (N,
6354 -- If it is a function call it can appear in elaboration code and
6355 -- the called entity must be frozen here.
6357 if Ekind (Subp) = E_Function then
6358 Freeze_Expression (Name (N));
6361 -- Analyze and resolve the new call. The actuals have already been
6362 -- resolved, but expansion of a function call will add extra actuals
6363 -- if needed. Analysis of a procedure call already includes resolution.
6367 if Ekind (Subp) = E_Function then
6368 Resolve (N, Etype (Subp));
6370 end Expand_Protected_Subprogram_Call;
6372 --------------------------------------------
6373 -- Has_Unconstrained_Access_Discriminants --
6374 --------------------------------------------
6376 function Has_Unconstrained_Access_Discriminants
6377 (Subtyp : Entity_Id) return Boolean
6382 if Has_Discriminants (Subtyp)
6383 and then not Is_Constrained (Subtyp)
6385 Discr := First_Discriminant (Subtyp);
6386 while Present (Discr) loop
6387 if Ekind (Etype (Discr)) = E_Anonymous_Access_Type then
6391 Next_Discriminant (Discr);
6396 end Has_Unconstrained_Access_Discriminants;
6398 -----------------------------------
6399 -- Expand_Simple_Function_Return --
6400 -----------------------------------
6402 -- The "simple" comes from the syntax rule simple_return_statement. The
6403 -- semantics are not at all simple!
6405 procedure Expand_Simple_Function_Return (N : Node_Id) is
6406 Loc : constant Source_Ptr := Sloc (N);
6408 Scope_Id : constant Entity_Id :=
6409 Return_Applies_To (Return_Statement_Entity (N));
6410 -- The function we are returning from
6412 R_Type : constant Entity_Id := Etype (Scope_Id);
6413 -- The result type of the function
6415 Utyp : constant Entity_Id := Underlying_Type (R_Type);
6417 Exp : constant Node_Id := Expression (N);
6418 pragma Assert (Present (Exp));
6420 Exptyp : constant Entity_Id := Etype (Exp);
6421 -- The type of the expression (not necessarily the same as R_Type)
6423 Subtype_Ind : Node_Id;
6424 -- If the result type of the function is class-wide and the expression
6425 -- has a specific type, then we use the expression's type as the type of
6426 -- the return object. In cases where the expression is an aggregate that
6427 -- is built in place, this avoids the need for an expensive conversion
6428 -- of the return object to the specific type on assignments to the
6429 -- individual components.
6432 if Is_Class_Wide_Type (R_Type)
6433 and then not Is_Class_Wide_Type (Etype (Exp))
6435 Subtype_Ind := New_Occurrence_Of (Etype (Exp), Loc);
6437 Subtype_Ind := New_Occurrence_Of (R_Type, Loc);
6440 -- For the case of a simple return that does not come from an extended
6441 -- return, in the case of Ada 2005 where we are returning a limited
6442 -- type, we rewrite "return <expression>;" to be:
6444 -- return _anon_ : <return_subtype> := <expression>
6446 -- The expansion produced by Expand_N_Extended_Return_Statement will
6447 -- contain simple return statements (for example, a block containing
6448 -- simple return of the return object), which brings us back here with
6449 -- Comes_From_Extended_Return_Statement set. The reason for the barrier
6450 -- checking for a simple return that does not come from an extended
6451 -- return is to avoid this infinite recursion.
6453 -- The reason for this design is that for Ada 2005 limited returns, we
6454 -- need to reify the return object, so we can build it "in place", and
6455 -- we need a block statement to hang finalization and tasking stuff.
6457 -- ??? In order to avoid disruption, we avoid translating to extended
6458 -- return except in the cases where we really need to (Ada 2005 for
6459 -- inherently limited). We might prefer to do this translation in all
6460 -- cases (except perhaps for the case of Ada 95 inherently limited),
6461 -- in order to fully exercise the Expand_N_Extended_Return_Statement
6462 -- code. This would also allow us to do the build-in-place optimization
6463 -- for efficiency even in cases where it is semantically not required.
6465 -- As before, we check the type of the return expression rather than the
6466 -- return type of the function, because the latter may be a limited
6467 -- class-wide interface type, which is not a limited type, even though
6468 -- the type of the expression may be.
6470 if not Comes_From_Extended_Return_Statement (N)
6471 and then Is_Immutably_Limited_Type (Etype (Expression (N)))
6472 and then Ada_Version >= Ada_2005
6473 and then not Debug_Flag_Dot_L
6476 Return_Object_Entity : constant Entity_Id :=
6477 Make_Temporary (Loc, 'R', Exp);
6478 Obj_Decl : constant Node_Id :=
6479 Make_Object_Declaration (Loc,
6480 Defining_Identifier => Return_Object_Entity,
6481 Object_Definition => Subtype_Ind,
6484 Ext : constant Node_Id := Make_Extended_Return_Statement (Loc,
6485 Return_Object_Declarations => New_List (Obj_Decl));
6486 -- Do not perform this high-level optimization if the result type
6487 -- is an interface because the "this" pointer must be displaced.
6496 -- Here we have a simple return statement that is part of the expansion
6497 -- of an extended return statement (either written by the user, or
6498 -- generated by the above code).
6500 -- Always normalize C/Fortran boolean result. This is not always needed,
6501 -- but it seems a good idea to minimize the passing around of non-
6502 -- normalized values, and in any case this handles the processing of
6503 -- barrier functions for protected types, which turn the condition into
6504 -- a return statement.
6506 if Is_Boolean_Type (Exptyp)
6507 and then Nonzero_Is_True (Exptyp)
6509 Adjust_Condition (Exp);
6510 Adjust_Result_Type (Exp, Exptyp);
6513 -- Do validity check if enabled for returns
6515 if Validity_Checks_On
6516 and then Validity_Check_Returns
6521 -- Check the result expression of a scalar function against the subtype
6522 -- of the function by inserting a conversion. This conversion must
6523 -- eventually be performed for other classes of types, but for now it's
6524 -- only done for scalars.
6527 if Is_Scalar_Type (Exptyp) then
6528 Rewrite (Exp, Convert_To (R_Type, Exp));
6530 -- The expression is resolved to ensure that the conversion gets
6531 -- expanded to generate a possible constraint check.
6533 Analyze_And_Resolve (Exp, R_Type);
6536 -- Deal with returning variable length objects and controlled types
6538 -- Nothing to do if we are returning by reference, or this is not a
6539 -- type that requires special processing (indicated by the fact that
6540 -- it requires a cleanup scope for the secondary stack case).
6542 if Is_Immutably_Limited_Type (Exptyp)
6543 or else Is_Limited_Interface (Exptyp)
6547 elsif not Requires_Transient_Scope (R_Type) then
6549 -- Mutable records with no variable length components are not
6550 -- returned on the sec-stack, so we need to make sure that the
6551 -- backend will only copy back the size of the actual value, and not
6552 -- the maximum size. We create an actual subtype for this purpose.
6555 Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exptyp));
6559 if Has_Discriminants (Ubt)
6560 and then not Is_Constrained (Ubt)
6561 and then not Has_Unchecked_Union (Ubt)
6563 Decl := Build_Actual_Subtype (Ubt, Exp);
6564 Ent := Defining_Identifier (Decl);
6565 Insert_Action (Exp, Decl);
6566 Rewrite (Exp, Unchecked_Convert_To (Ent, Exp));
6567 Analyze_And_Resolve (Exp);
6571 -- Here if secondary stack is used
6574 -- Make sure that no surrounding block will reclaim the secondary
6575 -- stack on which we are going to put the result. Not only may this
6576 -- introduce secondary stack leaks but worse, if the reclamation is
6577 -- done too early, then the result we are returning may get
6584 while Ekind (S) = E_Block or else Ekind (S) = E_Loop loop
6585 Set_Sec_Stack_Needed_For_Return (S, True);
6586 S := Enclosing_Dynamic_Scope (S);
6590 -- Optimize the case where the result is a function call. In this
6591 -- case either the result is already on the secondary stack, or is
6592 -- already being returned with the stack pointer depressed and no
6593 -- further processing is required except to set the By_Ref flag
6594 -- to ensure that gigi does not attempt an extra unnecessary copy.
6595 -- (actually not just unnecessary but harmfully wrong in the case
6596 -- of a controlled type, where gigi does not know how to do a copy).
6597 -- To make up for a gcc 2.8.1 deficiency (???), we perform the copy
6598 -- for array types if the constrained status of the target type is
6599 -- different from that of the expression.
6601 if Requires_Transient_Scope (Exptyp)
6603 (not Is_Array_Type (Exptyp)
6604 or else Is_Constrained (Exptyp) = Is_Constrained (R_Type)
6605 or else CW_Or_Has_Controlled_Part (Utyp))
6606 and then Nkind (Exp) = N_Function_Call
6610 -- Remove side effects from the expression now so that other parts
6611 -- of the expander do not have to reanalyze this node without this
6614 Rewrite (Exp, Duplicate_Subexpr_No_Checks (Exp));
6616 -- For controlled types, do the allocation on the secondary stack
6617 -- manually in order to call adjust at the right time:
6619 -- type Anon1 is access R_Type;
6620 -- for Anon1'Storage_pool use ss_pool;
6621 -- Anon2 : anon1 := new R_Type'(expr);
6622 -- return Anon2.all;
6624 -- We do the same for classwide types that are not potentially
6625 -- controlled (by the virtue of restriction No_Finalization) because
6626 -- gigi is not able to properly allocate class-wide types.
6628 elsif CW_Or_Has_Controlled_Part (Utyp) then
6630 Loc : constant Source_Ptr := Sloc (N);
6631 Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
6632 Alloc_Node : Node_Id;
6636 Set_Ekind (Acc_Typ, E_Access_Type);
6638 Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool));
6640 -- This is an allocator for the secondary stack, and it's fine
6641 -- to have Comes_From_Source set False on it, as gigi knows not
6642 -- to flag it as a violation of No_Implicit_Heap_Allocations.
6645 Make_Allocator (Loc,
6647 Make_Qualified_Expression (Loc,
6648 Subtype_Mark => New_Reference_To (Etype (Exp), Loc),
6649 Expression => Relocate_Node (Exp)));
6651 -- We do not want discriminant checks on the declaration,
6652 -- given that it gets its value from the allocator.
6654 Set_No_Initialization (Alloc_Node);
6656 Temp := Make_Temporary (Loc, 'R', Alloc_Node);
6658 Insert_List_Before_And_Analyze (N, New_List (
6659 Make_Full_Type_Declaration (Loc,
6660 Defining_Identifier => Acc_Typ,
6662 Make_Access_To_Object_Definition (Loc,
6663 Subtype_Indication => Subtype_Ind)),
6665 Make_Object_Declaration (Loc,
6666 Defining_Identifier => Temp,
6667 Object_Definition => New_Reference_To (Acc_Typ, Loc),
6668 Expression => Alloc_Node)));
6671 Make_Explicit_Dereference (Loc,
6672 Prefix => New_Reference_To (Temp, Loc)));
6674 Analyze_And_Resolve (Exp, R_Type);
6677 -- Otherwise use the gigi mechanism to allocate result on the
6681 Check_Restriction (No_Secondary_Stack, N);
6682 Set_Storage_Pool (N, RTE (RE_SS_Pool));
6684 -- If we are generating code for the VM do not use
6685 -- SS_Allocate since everything is heap-allocated anyway.
6687 if VM_Target = No_VM then
6688 Set_Procedure_To_Call (N, RTE (RE_SS_Allocate));
6693 -- Implement the rules of 6.5(8-10), which require a tag check in
6694 -- the case of a limited tagged return type, and tag reassignment for
6695 -- nonlimited tagged results. These actions are needed when the return
6696 -- type is a specific tagged type and the result expression is a
6697 -- conversion or a formal parameter, because in that case the tag of
6698 -- the expression might differ from the tag of the specific result type.
6700 if Is_Tagged_Type (Utyp)
6701 and then not Is_Class_Wide_Type (Utyp)
6702 and then (Nkind_In (Exp, N_Type_Conversion,
6703 N_Unchecked_Type_Conversion)
6704 or else (Is_Entity_Name (Exp)
6705 and then Ekind (Entity (Exp)) in Formal_Kind))
6707 -- When the return type is limited, perform a check that the tag of
6708 -- the result is the same as the tag of the return type.
6710 if Is_Limited_Type (R_Type) then
6712 Make_Raise_Constraint_Error (Loc,
6716 Make_Selected_Component (Loc,
6717 Prefix => Duplicate_Subexpr (Exp),
6718 Selector_Name => Make_Identifier (Loc, Name_uTag)),
6720 Make_Attribute_Reference (Loc,
6722 New_Occurrence_Of (Base_Type (Utyp), Loc),
6723 Attribute_Name => Name_Tag)),
6724 Reason => CE_Tag_Check_Failed));
6726 -- If the result type is a specific nonlimited tagged type, then we
6727 -- have to ensure that the tag of the result is that of the result
6728 -- type. This is handled by making a copy of the expression in
6729 -- the case where it might have a different tag, namely when the
6730 -- expression is a conversion or a formal parameter. We create a new
6731 -- object of the result type and initialize it from the expression,
6732 -- which will implicitly force the tag to be set appropriately.
6736 ExpR : constant Node_Id := Relocate_Node (Exp);
6737 Result_Id : constant Entity_Id :=
6738 Make_Temporary (Loc, 'R', ExpR);
6739 Result_Exp : constant Node_Id :=
6740 New_Reference_To (Result_Id, Loc);
6741 Result_Obj : constant Node_Id :=
6742 Make_Object_Declaration (Loc,
6743 Defining_Identifier => Result_Id,
6744 Object_Definition =>
6745 New_Reference_To (R_Type, Loc),
6746 Constant_Present => True,
6747 Expression => ExpR);
6750 Set_Assignment_OK (Result_Obj);
6751 Insert_Action (Exp, Result_Obj);
6753 Rewrite (Exp, Result_Exp);
6754 Analyze_And_Resolve (Exp, R_Type);
6758 -- Ada 2005 (AI-344): If the result type is class-wide, then insert
6759 -- a check that the level of the return expression's underlying type
6760 -- is not deeper than the level of the master enclosing the function.
6761 -- Always generate the check when the type of the return expression
6762 -- is class-wide, when it's a type conversion, or when it's a formal
6763 -- parameter. Otherwise, suppress the check in the case where the
6764 -- return expression has a specific type whose level is known not to
6765 -- be statically deeper than the function's result type.
6767 -- Note: accessibility check is skipped in the VM case, since there
6768 -- does not seem to be any practical way to implement this check.
6770 elsif Ada_Version >= Ada_2005
6771 and then Tagged_Type_Expansion
6772 and then Is_Class_Wide_Type (R_Type)
6773 and then not Scope_Suppress (Accessibility_Check)
6775 (Is_Class_Wide_Type (Etype (Exp))
6776 or else Nkind_In (Exp, N_Type_Conversion,
6777 N_Unchecked_Type_Conversion)
6778 or else (Is_Entity_Name (Exp)
6779 and then Ekind (Entity (Exp)) in Formal_Kind)
6780 or else Scope_Depth (Enclosing_Dynamic_Scope (Etype (Exp))) >
6781 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))
6787 -- Ada 2005 (AI-251): In class-wide interface objects we displace
6788 -- "this" to reference the base of the object. This is required to
6789 -- get access to the TSD of the object.
6791 if Is_Class_Wide_Type (Etype (Exp))
6792 and then Is_Interface (Etype (Exp))
6793 and then Nkind (Exp) = N_Explicit_Dereference
6796 Make_Explicit_Dereference (Loc,
6798 Unchecked_Convert_To (RTE (RE_Tag_Ptr),
6799 Make_Function_Call (Loc,
6801 New_Reference_To (RTE (RE_Base_Address), Loc),
6802 Parameter_Associations => New_List (
6803 Unchecked_Convert_To (RTE (RE_Address),
6804 Duplicate_Subexpr (Prefix (Exp)))))));
6807 Make_Attribute_Reference (Loc,
6808 Prefix => Duplicate_Subexpr (Exp),
6809 Attribute_Name => Name_Tag);
6813 Make_Raise_Program_Error (Loc,
6816 Left_Opnd => Build_Get_Access_Level (Loc, Tag_Node),
6818 Make_Integer_Literal (Loc,
6819 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))),
6820 Reason => PE_Accessibility_Check_Failed));
6823 -- AI05-0073: If function has a controlling access result, check that
6824 -- the tag of the return value, if it is not null, matches designated
6825 -- type of return type.
6826 -- The return expression is referenced twice in the code below, so
6827 -- it must be made free of side effects. Given that different compilers
6828 -- may evaluate these parameters in different order, both occurrences
6831 elsif Ekind (R_Type) = E_Anonymous_Access_Type
6832 and then Has_Controlling_Result (Scope_Id)
6835 Make_Raise_Constraint_Error (Loc,
6840 Left_Opnd => Duplicate_Subexpr (Exp),
6841 Right_Opnd => Make_Null (Loc)),
6843 Right_Opnd => Make_Op_Ne (Loc,
6845 Make_Selected_Component (Loc,
6846 Prefix => Duplicate_Subexpr (Exp),
6847 Selector_Name => Make_Identifier (Loc, Name_uTag)),
6850 Make_Attribute_Reference (Loc,
6852 New_Occurrence_Of (Designated_Type (R_Type), Loc),
6853 Attribute_Name => Name_Tag))),
6855 Reason => CE_Tag_Check_Failed),
6856 Suppress => All_Checks);
6859 -- AI05-0234: RM 6.5(21/3). Check access discriminants to
6860 -- ensure that the function result does not outlive an
6861 -- object designated by one of it discriminants.
6863 if Present (Extra_Accessibility_Of_Result (Scope_Id))
6864 and then Has_Unconstrained_Access_Discriminants (R_Type)
6867 Discrim_Source : Node_Id;
6869 procedure Check_Against_Result_Level (Level : Node_Id);
6870 -- Check the given accessibility level against the level
6871 -- determined by the point of call. (AI05-0234).
6873 --------------------------------
6874 -- Check_Against_Result_Level --
6875 --------------------------------
6877 procedure Check_Against_Result_Level (Level : Node_Id) is
6880 Make_Raise_Program_Error (Loc,
6886 (Extra_Accessibility_Of_Result (Scope_Id), Loc)),
6887 Reason => PE_Accessibility_Check_Failed));
6888 end Check_Against_Result_Level;
6891 Discrim_Source := Exp;
6892 while Nkind (Discrim_Source) = N_Qualified_Expression loop
6893 Discrim_Source := Expression (Discrim_Source);
6896 if Nkind (Discrim_Source) = N_Identifier
6897 and then Is_Return_Object (Entity (Discrim_Source))
6899 Discrim_Source := Entity (Discrim_Source);
6901 if Is_Constrained (Etype (Discrim_Source)) then
6902 Discrim_Source := Etype (Discrim_Source);
6904 Discrim_Source := Expression (Parent (Discrim_Source));
6907 elsif Nkind (Discrim_Source) = N_Identifier
6908 and then Nkind_In (Original_Node (Discrim_Source),
6909 N_Aggregate, N_Extension_Aggregate)
6911 Discrim_Source := Original_Node (Discrim_Source);
6913 elsif Nkind (Discrim_Source) = N_Explicit_Dereference and then
6914 Nkind (Original_Node (Discrim_Source)) = N_Function_Call
6916 Discrim_Source := Original_Node (Discrim_Source);
6919 while Nkind_In (Discrim_Source, N_Qualified_Expression,
6921 N_Unchecked_Type_Conversion)
6923 Discrim_Source := Expression (Discrim_Source);
6926 case Nkind (Discrim_Source) is
6927 when N_Defining_Identifier =>
6929 pragma Assert (Is_Composite_Type (Discrim_Source)
6930 and then Has_Discriminants (Discrim_Source)
6931 and then Is_Constrained (Discrim_Source));
6934 Discrim : Entity_Id :=
6935 First_Discriminant (Base_Type (R_Type));
6936 Disc_Elmt : Elmt_Id :=
6937 First_Elmt (Discriminant_Constraint
6941 if Ekind (Etype (Discrim)) =
6942 E_Anonymous_Access_Type
6944 Check_Against_Result_Level
6945 (Dynamic_Accessibility_Level (Node (Disc_Elmt)));
6948 Next_Elmt (Disc_Elmt);
6949 Next_Discriminant (Discrim);
6950 exit when not Present (Discrim);
6954 when N_Aggregate | N_Extension_Aggregate =>
6956 -- Unimplemented: extension aggregate case where discrims
6957 -- come from ancestor part, not extension part.
6960 Discrim : Entity_Id :=
6961 First_Discriminant (Base_Type (R_Type));
6963 Disc_Exp : Node_Id := Empty;
6965 Positionals_Exhausted
6966 : Boolean := not Present (Expressions
6969 function Associated_Expr
6970 (Comp_Id : Entity_Id;
6971 Associations : List_Id) return Node_Id;
6973 -- Given a component and a component associations list,
6974 -- locate the expression for that component; returns
6975 -- Empty if no such expression is found.
6977 ---------------------
6978 -- Associated_Expr --
6979 ---------------------
6981 function Associated_Expr
6982 (Comp_Id : Entity_Id;
6983 Associations : List_Id) return Node_Id
6989 -- Simple linear search seems ok here
6991 Assoc := First (Associations);
6992 while Present (Assoc) loop
6993 Choice := First (Choices (Assoc));
6994 while Present (Choice) loop
6995 if (Nkind (Choice) = N_Identifier
6996 and then Chars (Choice) = Chars (Comp_Id))
6997 or else (Nkind (Choice) = N_Others_Choice)
6999 return Expression (Assoc);
7009 end Associated_Expr;
7011 -- Start of processing for Expand_Simple_Function_Return
7014 if not Positionals_Exhausted then
7015 Disc_Exp := First (Expressions (Discrim_Source));
7019 if Positionals_Exhausted then
7023 Component_Associations (Discrim_Source));
7026 if Ekind (Etype (Discrim)) =
7027 E_Anonymous_Access_Type
7029 Check_Against_Result_Level
7030 (Dynamic_Accessibility_Level (Disc_Exp));
7033 Next_Discriminant (Discrim);
7034 exit when not Present (Discrim);
7036 if not Positionals_Exhausted then
7038 Positionals_Exhausted := not Present (Disc_Exp);
7043 when N_Function_Call =>
7045 -- No check needed (check performed by callee)
7052 Level : constant Node_Id :=
7053 Make_Integer_Literal (Loc,
7054 Object_Access_Level (Discrim_Source));
7057 -- Unimplemented: check for name prefix that includes
7058 -- a dereference of an access value with a dynamic
7059 -- accessibility level (e.g., an access param or a
7060 -- saooaaat) and use dynamic level in that case. For
7062 -- return Access_Param.all(Some_Index).Some_Component;
7065 Set_Etype (Level, Standard_Natural);
7066 Check_Against_Result_Level (Level);
7073 -- If we are returning an object that may not be bit-aligned, then copy
7074 -- the value into a temporary first. This copy may need to expand to a
7075 -- loop of component operations.
7077 if Is_Possibly_Unaligned_Slice (Exp)
7078 or else Is_Possibly_Unaligned_Object (Exp)
7081 ExpR : constant Node_Id := Relocate_Node (Exp);
7082 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
7085 Make_Object_Declaration (Loc,
7086 Defining_Identifier => Tnn,
7087 Constant_Present => True,
7088 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7089 Expression => ExpR),
7090 Suppress => All_Checks);
7091 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7095 -- Generate call to postcondition checks if they are present
7097 if Ekind (Scope_Id) = E_Function
7098 and then Has_Postconditions (Scope_Id)
7100 -- We are going to reference the returned value twice in this case,
7101 -- once in the call to _Postconditions, and once in the actual return
7102 -- statement, but we can't have side effects happening twice, and in
7103 -- any case for efficiency we don't want to do the computation twice.
7105 -- If the returned expression is an entity name, we don't need to
7106 -- worry since it is efficient and safe to reference it twice, that's
7107 -- also true for literals other than string literals, and for the
7108 -- case of X.all where X is an entity name.
7110 if Is_Entity_Name (Exp)
7111 or else Nkind_In (Exp, N_Character_Literal,
7114 or else (Nkind (Exp) = N_Explicit_Dereference
7115 and then Is_Entity_Name (Prefix (Exp)))
7119 -- Otherwise we are going to need a temporary to capture the value
7123 ExpR : constant Node_Id := Relocate_Node (Exp);
7124 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
7127 -- For a complex expression of an elementary type, capture
7128 -- value in the temporary and use it as the reference.
7130 if Is_Elementary_Type (R_Type) then
7132 Make_Object_Declaration (Loc,
7133 Defining_Identifier => Tnn,
7134 Constant_Present => True,
7135 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7136 Expression => ExpR),
7137 Suppress => All_Checks);
7139 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7141 -- If we have something we can rename, generate a renaming of
7142 -- the object and replace the expression with a reference
7144 elsif Is_Object_Reference (Exp) then
7146 Make_Object_Renaming_Declaration (Loc,
7147 Defining_Identifier => Tnn,
7148 Subtype_Mark => New_Occurrence_Of (R_Type, Loc),
7150 Suppress => All_Checks);
7152 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7154 -- Otherwise we have something like a string literal or an
7155 -- aggregate. We could copy the value, but that would be
7156 -- inefficient. Instead we make a reference to the value and
7157 -- capture this reference with a renaming, the expression is
7158 -- then replaced by a dereference of this renaming.
7161 -- For now, copy the value, since the code below does not
7162 -- seem to work correctly ???
7165 Make_Object_Declaration (Loc,
7166 Defining_Identifier => Tnn,
7167 Constant_Present => True,
7168 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7169 Expression => Relocate_Node (Exp)),
7170 Suppress => All_Checks);
7172 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7174 -- Insert_Action (Exp,
7175 -- Make_Object_Renaming_Declaration (Loc,
7176 -- Defining_Identifier => Tnn,
7177 -- Access_Definition =>
7178 -- Make_Access_Definition (Loc,
7179 -- All_Present => True,
7180 -- Subtype_Mark => New_Occurrence_Of (R_Type, Loc)),
7182 -- Make_Reference (Loc,
7183 -- Prefix => Relocate_Node (Exp))),
7184 -- Suppress => All_Checks);
7187 -- Make_Explicit_Dereference (Loc,
7188 -- Prefix => New_Occurrence_Of (Tnn, Loc)));
7193 -- Generate call to _postconditions
7196 Make_Procedure_Call_Statement (Loc,
7197 Name => Make_Identifier (Loc, Name_uPostconditions),
7198 Parameter_Associations => New_List (Duplicate_Subexpr (Exp))));
7201 -- Ada 2005 (AI-251): If this return statement corresponds with an
7202 -- simple return statement associated with an extended return statement
7203 -- and the type of the returned object is an interface then generate an
7204 -- implicit conversion to force displacement of the "this" pointer.
7206 if Ada_Version >= Ada_2005
7207 and then Comes_From_Extended_Return_Statement (N)
7208 and then Nkind (Expression (N)) = N_Identifier
7209 and then Is_Interface (Utyp)
7210 and then Utyp /= Underlying_Type (Exptyp)
7212 Rewrite (Exp, Convert_To (Utyp, Relocate_Node (Exp)));
7213 Analyze_And_Resolve (Exp);
7215 end Expand_Simple_Function_Return;
7217 --------------------------------
7218 -- Is_Build_In_Place_Function --
7219 --------------------------------
7221 function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is
7223 -- This function is called from Expand_Subtype_From_Expr during
7224 -- semantic analysis, even when expansion is off. In those cases
7225 -- the build_in_place expansion will not take place.
7227 if not Expander_Active then
7231 -- For now we test whether E denotes a function or access-to-function
7232 -- type whose result subtype is inherently limited. Later this test may
7233 -- be revised to allow composite nonlimited types. Functions with a
7234 -- foreign convention or whose result type has a foreign convention
7237 if Ekind_In (E, E_Function, E_Generic_Function)
7238 or else (Ekind (E) = E_Subprogram_Type
7239 and then Etype (E) /= Standard_Void_Type)
7241 -- Note: If you have Convention (C) on an inherently limited type,
7242 -- you're on your own. That is, the C code will have to be carefully
7243 -- written to know about the Ada conventions.
7245 if Has_Foreign_Convention (E)
7246 or else Has_Foreign_Convention (Etype (E))
7250 -- In Ada 2005 all functions with an inherently limited return type
7251 -- must be handled using a build-in-place profile, including the case
7252 -- of a function with a limited interface result, where the function
7253 -- may return objects of nonlimited descendants.
7256 return Is_Immutably_Limited_Type (Etype (E))
7257 and then Ada_Version >= Ada_2005
7258 and then not Debug_Flag_Dot_L;
7264 end Is_Build_In_Place_Function;
7266 -------------------------------------
7267 -- Is_Build_In_Place_Function_Call --
7268 -------------------------------------
7270 function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is
7271 Exp_Node : Node_Id := N;
7272 Function_Id : Entity_Id;
7275 -- Return False when the expander is inactive, since awareness of
7276 -- build-in-place treatment is only relevant during expansion. Note that
7277 -- Is_Build_In_Place_Function, which is called as part of this function,
7278 -- is also conditioned this way, but we need to check here as well to
7279 -- avoid blowing up on processing protected calls when expansion is
7280 -- disabled (such as with -gnatc) since those would trip over the raise
7281 -- of Program_Error below.
7283 if not Expander_Active then
7287 -- Step past qualification or unchecked conversion (the latter can occur
7288 -- in cases of calls to 'Input).
7290 if Nkind_In (Exp_Node, N_Qualified_Expression,
7291 N_Unchecked_Type_Conversion)
7293 Exp_Node := Expression (N);
7296 if Nkind (Exp_Node) /= N_Function_Call then
7300 -- In Alfa mode, build-in-place calls are not expanded, so that we
7301 -- may end up with a call that is neither resolved to an entity, nor
7302 -- an indirect call.
7307 elsif Is_Entity_Name (Name (Exp_Node)) then
7308 Function_Id := Entity (Name (Exp_Node));
7310 -- In the case of an explicitly dereferenced call, use the subprogram
7311 -- type generated for the dereference.
7313 elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then
7314 Function_Id := Etype (Name (Exp_Node));
7317 raise Program_Error;
7320 return Is_Build_In_Place_Function (Function_Id);
7322 end Is_Build_In_Place_Function_Call;
7324 -----------------------
7325 -- Freeze_Subprogram --
7326 -----------------------
7328 procedure Freeze_Subprogram (N : Node_Id) is
7329 Loc : constant Source_Ptr := Sloc (N);
7331 procedure Register_Predefined_DT_Entry (Prim : Entity_Id);
7332 -- (Ada 2005): Register a predefined primitive in all the secondary
7333 -- dispatch tables of its primitive type.
7335 ----------------------------------
7336 -- Register_Predefined_DT_Entry --
7337 ----------------------------------
7339 procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is
7340 Iface_DT_Ptr : Elmt_Id;
7341 Tagged_Typ : Entity_Id;
7342 Thunk_Id : Entity_Id;
7343 Thunk_Code : Node_Id;
7346 Tagged_Typ := Find_Dispatching_Type (Prim);
7348 if No (Access_Disp_Table (Tagged_Typ))
7349 or else not Has_Interfaces (Tagged_Typ)
7350 or else not RTE_Available (RE_Interface_Tag)
7351 or else Restriction_Active (No_Dispatching_Calls)
7356 -- Skip the first two access-to-dispatch-table pointers since they
7357 -- leads to the primary dispatch table (predefined DT and user
7358 -- defined DT). We are only concerned with the secondary dispatch
7359 -- table pointers. Note that the access-to- dispatch-table pointer
7360 -- corresponds to the first implemented interface retrieved below.
7363 Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ))));
7365 while Present (Iface_DT_Ptr)
7366 and then Ekind (Node (Iface_DT_Ptr)) = E_Constant
7368 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
7369 Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code);
7371 if Present (Thunk_Code) then
7372 Insert_Actions_After (N, New_List (
7375 Build_Set_Predefined_Prim_Op_Address (Loc,
7377 New_Reference_To (Node (Next_Elmt (Iface_DT_Ptr)), Loc),
7378 Position => DT_Position (Prim),
7380 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
7381 Make_Attribute_Reference (Loc,
7382 Prefix => New_Reference_To (Thunk_Id, Loc),
7383 Attribute_Name => Name_Unrestricted_Access))),
7385 Build_Set_Predefined_Prim_Op_Address (Loc,
7388 (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))),
7390 Position => DT_Position (Prim),
7392 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
7393 Make_Attribute_Reference (Loc,
7394 Prefix => New_Reference_To (Prim, Loc),
7395 Attribute_Name => Name_Unrestricted_Access)))));
7398 -- Skip the tag of the predefined primitives dispatch table
7400 Next_Elmt (Iface_DT_Ptr);
7401 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
7403 -- Skip tag of the no-thunks dispatch table
7405 Next_Elmt (Iface_DT_Ptr);
7406 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
7408 -- Skip tag of predefined primitives no-thunks dispatch table
7410 Next_Elmt (Iface_DT_Ptr);
7411 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
7413 Next_Elmt (Iface_DT_Ptr);
7415 end Register_Predefined_DT_Entry;
7419 Subp : constant Entity_Id := Entity (N);
7421 -- Start of processing for Freeze_Subprogram
7424 -- We suppress the initialization of the dispatch table entry when
7425 -- VM_Target because the dispatching mechanism is handled internally
7428 if Is_Dispatching_Operation (Subp)
7429 and then not Is_Abstract_Subprogram (Subp)
7430 and then Present (DTC_Entity (Subp))
7431 and then Present (Scope (DTC_Entity (Subp)))
7432 and then Tagged_Type_Expansion
7433 and then not Restriction_Active (No_Dispatching_Calls)
7434 and then RTE_Available (RE_Tag)
7437 Typ : constant Entity_Id := Scope (DTC_Entity (Subp));
7440 -- Handle private overridden primitives
7442 if not Is_CPP_Class (Typ) then
7443 Check_Overriding_Operation (Subp);
7446 -- We assume that imported CPP primitives correspond with objects
7447 -- whose constructor is in the CPP side; therefore we don't need
7448 -- to generate code to register them in the dispatch table.
7450 if Is_CPP_Class (Typ) then
7453 -- Handle CPP primitives found in derivations of CPP_Class types.
7454 -- These primitives must have been inherited from some parent, and
7455 -- there is no need to register them in the dispatch table because
7456 -- Build_Inherit_Prims takes care of the initialization of these
7459 elsif Is_Imported (Subp)
7460 and then (Convention (Subp) = Convention_CPP
7461 or else Convention (Subp) = Convention_C)
7465 -- Generate code to register the primitive in non statically
7466 -- allocated dispatch tables
7468 elsif not Building_Static_DT (Scope (DTC_Entity (Subp))) then
7470 -- When a primitive is frozen, enter its name in its dispatch
7473 if not Is_Interface (Typ)
7474 or else Present (Interface_Alias (Subp))
7476 if Is_Predefined_Dispatching_Operation (Subp) then
7477 Register_Predefined_DT_Entry (Subp);
7480 Insert_Actions_After (N,
7481 Register_Primitive (Loc, Prim => Subp));
7487 -- Mark functions that return by reference. Note that it cannot be part
7488 -- of the normal semantic analysis of the spec since the underlying
7489 -- returned type may not be known yet (for private types).
7492 Typ : constant Entity_Id := Etype (Subp);
7493 Utyp : constant Entity_Id := Underlying_Type (Typ);
7495 if Is_Immutably_Limited_Type (Typ) then
7496 Set_Returns_By_Ref (Subp);
7497 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
7498 Set_Returns_By_Ref (Subp);
7501 end Freeze_Subprogram;
7503 -----------------------
7504 -- Is_Null_Procedure --
7505 -----------------------
7507 function Is_Null_Procedure (Subp : Entity_Id) return Boolean is
7508 Decl : constant Node_Id := Unit_Declaration_Node (Subp);
7511 if Ekind (Subp) /= E_Procedure then
7514 -- Check if this is a declared null procedure
7516 elsif Nkind (Decl) = N_Subprogram_Declaration then
7517 if not Null_Present (Specification (Decl)) then
7520 elsif No (Body_To_Inline (Decl)) then
7523 -- Check if the body contains only a null statement, followed by
7524 -- the return statement added during expansion.
7528 Orig_Bod : constant Node_Id := Body_To_Inline (Decl);
7534 if Nkind (Orig_Bod) /= N_Subprogram_Body then
7537 -- We must skip SCIL nodes because they are currently
7538 -- implemented as special N_Null_Statement nodes.
7542 (Statements (Handled_Statement_Sequence (Orig_Bod)));
7543 Stat2 := Next_Non_SCIL_Node (Stat);
7546 Is_Empty_List (Declarations (Orig_Bod))
7547 and then Nkind (Stat) = N_Null_Statement
7551 (Nkind (Stat2) = N_Simple_Return_Statement
7552 and then No (Next (Stat2))));
7560 end Is_Null_Procedure;
7562 -------------------------------------------
7563 -- Make_Build_In_Place_Call_In_Allocator --
7564 -------------------------------------------
7566 procedure Make_Build_In_Place_Call_In_Allocator
7567 (Allocator : Node_Id;
7568 Function_Call : Node_Id)
7570 Acc_Type : constant Entity_Id := Etype (Allocator);
7572 Func_Call : Node_Id := Function_Call;
7573 Function_Id : Entity_Id;
7574 Result_Subt : Entity_Id;
7575 New_Allocator : Node_Id;
7576 Return_Obj_Access : Entity_Id;
7579 -- Step past qualification or unchecked conversion (the latter can occur
7580 -- in cases of calls to 'Input).
7582 if Nkind_In (Func_Call,
7583 N_Qualified_Expression,
7584 N_Unchecked_Type_Conversion)
7586 Func_Call := Expression (Func_Call);
7589 -- If the call has already been processed to add build-in-place actuals
7590 -- then return. This should not normally occur in an allocator context,
7591 -- but we add the protection as a defensive measure.
7593 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7597 -- Mark the call as processed as a build-in-place call
7599 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7601 Loc := Sloc (Function_Call);
7603 if Is_Entity_Name (Name (Func_Call)) then
7604 Function_Id := Entity (Name (Func_Call));
7606 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7607 Function_Id := Etype (Name (Func_Call));
7610 raise Program_Error;
7613 Result_Subt := Available_View (Etype (Function_Id));
7615 -- Check whether return type includes tasks. This may not have been done
7616 -- previously, if the type was a limited view.
7618 if Has_Task (Result_Subt) then
7619 Build_Activation_Chain_Entity (Allocator);
7622 -- When the result subtype is constrained, the return object must be
7623 -- allocated on the caller side, and access to it is passed to the
7626 -- Here and in related routines, we must examine the full view of the
7627 -- type, because the view at the point of call may differ from that
7628 -- that in the function body, and the expansion mechanism depends on
7629 -- the characteristics of the full view.
7631 if Is_Constrained (Underlying_Type (Result_Subt)) then
7633 -- Replace the initialized allocator of form "new T'(Func (...))"
7634 -- with an uninitialized allocator of form "new T", where T is the
7635 -- result subtype of the called function. The call to the function
7636 -- is handled separately further below.
7639 Make_Allocator (Loc,
7640 Expression => New_Reference_To (Result_Subt, Loc));
7641 Set_No_Initialization (New_Allocator);
7643 -- Copy attributes to new allocator. Note that the new allocator
7644 -- logically comes from source if the original one did, so copy the
7645 -- relevant flag. This ensures proper treatment of the restriction
7646 -- No_Implicit_Heap_Allocations in this case.
7648 Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator));
7649 Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator));
7650 Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator));
7652 Rewrite (Allocator, New_Allocator);
7654 -- Create a new access object and initialize it to the result of the
7655 -- new uninitialized allocator. Note: we do not use Allocator as the
7656 -- Related_Node of Return_Obj_Access in call to Make_Temporary below
7657 -- as this would create a sort of infinite "recursion".
7659 Return_Obj_Access := Make_Temporary (Loc, 'R');
7660 Set_Etype (Return_Obj_Access, Acc_Type);
7662 Insert_Action (Allocator,
7663 Make_Object_Declaration (Loc,
7664 Defining_Identifier => Return_Obj_Access,
7665 Object_Definition => New_Reference_To (Acc_Type, Loc),
7666 Expression => Relocate_Node (Allocator)));
7668 -- When the function has a controlling result, an allocation-form
7669 -- parameter must be passed indicating that the caller is allocating
7670 -- the result object. This is needed because such a function can be
7671 -- called as a dispatching operation and must be treated similarly
7672 -- to functions with unconstrained result subtypes.
7674 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7675 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7677 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7678 (Func_Call, Function_Id, Acc_Type);
7680 Add_Task_Actuals_To_Build_In_Place_Call
7681 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
7683 -- Add an implicit actual to the function call that provides access
7684 -- to the allocated object. An unchecked conversion to the (specific)
7685 -- result subtype of the function is inserted to handle cases where
7686 -- the access type of the allocator has a class-wide designated type.
7688 Add_Access_Actual_To_Build_In_Place_Call
7691 Make_Unchecked_Type_Conversion (Loc,
7692 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
7694 Make_Explicit_Dereference (Loc,
7695 Prefix => New_Reference_To (Return_Obj_Access, Loc))));
7697 -- When the result subtype is unconstrained, the function itself must
7698 -- perform the allocation of the return object, so we pass parameters
7699 -- indicating that. We don't yet handle the case where the allocation
7700 -- must be done in a user-defined storage pool, which will require
7701 -- passing another actual or two to provide allocation/deallocation
7705 -- Case of a user-defined storage pool. Pass an allocation parameter
7706 -- indicating that the function should allocate its result in the
7707 -- pool, and pass the pool. Use 'Unrestricted_Access because the
7708 -- pool may not be aliased.
7710 if VM_Target = No_VM
7711 and then Present (Associated_Storage_Pool (Acc_Type))
7713 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7714 (Func_Call, Function_Id, Alloc_Form => User_Storage_Pool,
7716 Make_Attribute_Reference (Loc,
7719 (Associated_Storage_Pool (Acc_Type), Loc),
7720 Attribute_Name => Name_Unrestricted_Access));
7722 -- No user-defined pool; pass an allocation parameter indicating that
7723 -- the function should allocate its result on the heap.
7726 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7727 (Func_Call, Function_Id, Alloc_Form => Global_Heap);
7730 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7731 (Func_Call, Function_Id, Acc_Type);
7733 Add_Task_Actuals_To_Build_In_Place_Call
7734 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
7736 -- The caller does not provide the return object in this case, so we
7737 -- have to pass null for the object access actual.
7739 Add_Access_Actual_To_Build_In_Place_Call
7740 (Func_Call, Function_Id, Return_Object => Empty);
7743 -- If the build-in-place function call returns a controlled object,
7744 -- the finalization master will require a reference to routine
7745 -- Finalize_Address of the designated type. Setting this attribute
7746 -- is done in the same manner to expansion of allocators.
7748 if Needs_Finalization (Result_Subt) then
7750 -- Controlled types with supressed finalization do not need to
7751 -- associate the address of their Finalize_Address primitives with
7752 -- a master since they do not need a master to begin with.
7754 if Is_Library_Level_Entity (Acc_Type)
7755 and then Finalize_Storage_Only (Result_Subt)
7759 -- Do not generate the call to Set_Finalize_Address in Alfa mode
7760 -- because it is not necessary and results in unwanted expansion.
7761 -- This expansion is also not carried out in CodePeer mode because
7762 -- Finalize_Address is never built.
7765 and then not CodePeer_Mode
7767 Insert_Action (Allocator,
7768 Make_Set_Finalize_Address_Call (Loc,
7769 Typ => Etype (Function_Id),
7770 Ptr_Typ => Acc_Type));
7774 -- Finally, replace the allocator node with a reference to the result
7775 -- of the function call itself (which will effectively be an access
7776 -- to the object created by the allocator).
7778 Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call)));
7779 Analyze_And_Resolve (Allocator, Acc_Type);
7780 end Make_Build_In_Place_Call_In_Allocator;
7782 ---------------------------------------------------
7783 -- Make_Build_In_Place_Call_In_Anonymous_Context --
7784 ---------------------------------------------------
7786 procedure Make_Build_In_Place_Call_In_Anonymous_Context
7787 (Function_Call : Node_Id)
7790 Func_Call : Node_Id := Function_Call;
7791 Function_Id : Entity_Id;
7792 Result_Subt : Entity_Id;
7793 Return_Obj_Id : Entity_Id;
7794 Return_Obj_Decl : Entity_Id;
7797 -- Step past qualification or unchecked conversion (the latter can occur
7798 -- in cases of calls to 'Input).
7800 if Nkind_In (Func_Call, N_Qualified_Expression,
7801 N_Unchecked_Type_Conversion)
7803 Func_Call := Expression (Func_Call);
7806 -- If the call has already been processed to add build-in-place actuals
7807 -- then return. One place this can occur is for calls to build-in-place
7808 -- functions that occur within a call to a protected operation, where
7809 -- due to rewriting and expansion of the protected call there can be
7810 -- more than one call to Expand_Actuals for the same set of actuals.
7812 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7816 -- Mark the call as processed as a build-in-place call
7818 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7820 Loc := Sloc (Function_Call);
7822 if Is_Entity_Name (Name (Func_Call)) then
7823 Function_Id := Entity (Name (Func_Call));
7825 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7826 Function_Id := Etype (Name (Func_Call));
7829 raise Program_Error;
7832 Result_Subt := Etype (Function_Id);
7834 -- If the build-in-place function returns a controlled object, then the
7835 -- object needs to be finalized immediately after the context. Since
7836 -- this case produces a transient scope, the servicing finalizer needs
7837 -- to name the returned object. Create a temporary which is initialized
7838 -- with the function call:
7840 -- Temp_Id : Func_Type := BIP_Func_Call;
7842 -- The initialization expression of the temporary will be rewritten by
7843 -- the expander using the appropriate mechanism in Make_Build_In_Place_
7844 -- Call_In_Object_Declaration.
7846 if Needs_Finalization (Result_Subt) then
7848 Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'R');
7849 Temp_Decl : Node_Id;
7852 -- Reset the guard on the function call since the following does
7853 -- not perform actual call expansion.
7855 Set_Is_Expanded_Build_In_Place_Call (Func_Call, False);
7858 Make_Object_Declaration (Loc,
7859 Defining_Identifier => Temp_Id,
7860 Object_Definition =>
7861 New_Reference_To (Result_Subt, Loc),
7863 New_Copy_Tree (Function_Call));
7865 Insert_Action (Function_Call, Temp_Decl);
7867 Rewrite (Function_Call, New_Reference_To (Temp_Id, Loc));
7868 Analyze (Function_Call);
7871 -- When the result subtype is constrained, an object of the subtype is
7872 -- declared and an access value designating it is passed as an actual.
7874 elsif Is_Constrained (Underlying_Type (Result_Subt)) then
7876 -- Create a temporary object to hold the function result
7878 Return_Obj_Id := Make_Temporary (Loc, 'R');
7879 Set_Etype (Return_Obj_Id, Result_Subt);
7882 Make_Object_Declaration (Loc,
7883 Defining_Identifier => Return_Obj_Id,
7884 Aliased_Present => True,
7885 Object_Definition => New_Reference_To (Result_Subt, Loc));
7887 Set_No_Initialization (Return_Obj_Decl);
7889 Insert_Action (Func_Call, Return_Obj_Decl);
7891 -- When the function has a controlling result, an allocation-form
7892 -- parameter must be passed indicating that the caller is allocating
7893 -- the result object. This is needed because such a function can be
7894 -- called as a dispatching operation and must be treated similarly
7895 -- to functions with unconstrained result subtypes.
7897 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7898 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7900 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7901 (Func_Call, Function_Id);
7903 Add_Task_Actuals_To_Build_In_Place_Call
7904 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
7906 -- Add an implicit actual to the function call that provides access
7907 -- to the caller's return object.
7909 Add_Access_Actual_To_Build_In_Place_Call
7910 (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc));
7912 -- When the result subtype is unconstrained, the function must allocate
7913 -- the return object in the secondary stack, so appropriate implicit
7914 -- parameters are added to the call to indicate that. A transient
7915 -- scope is established to ensure eventual cleanup of the result.
7918 -- Pass an allocation parameter indicating that the function should
7919 -- allocate its result on the secondary stack.
7921 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7922 (Func_Call, Function_Id, Alloc_Form => Secondary_Stack);
7924 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7925 (Func_Call, Function_Id);
7927 Add_Task_Actuals_To_Build_In_Place_Call
7928 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
7930 -- Pass a null value to the function since no return object is
7931 -- available on the caller side.
7933 Add_Access_Actual_To_Build_In_Place_Call
7934 (Func_Call, Function_Id, Empty);
7936 end Make_Build_In_Place_Call_In_Anonymous_Context;
7938 --------------------------------------------
7939 -- Make_Build_In_Place_Call_In_Assignment --
7940 --------------------------------------------
7942 procedure Make_Build_In_Place_Call_In_Assignment
7944 Function_Call : Node_Id)
7946 Lhs : constant Node_Id := Name (Assign);
7947 Func_Call : Node_Id := Function_Call;
7948 Func_Id : Entity_Id;
7952 Ptr_Typ : Entity_Id;
7953 Ptr_Typ_Decl : Node_Id;
7954 Result_Subt : Entity_Id;
7958 -- Step past qualification or unchecked conversion (the latter can occur
7959 -- in cases of calls to 'Input).
7961 if Nkind_In (Func_Call, N_Qualified_Expression,
7962 N_Unchecked_Type_Conversion)
7964 Func_Call := Expression (Func_Call);
7967 -- If the call has already been processed to add build-in-place actuals
7968 -- then return. This should not normally occur in an assignment context,
7969 -- but we add the protection as a defensive measure.
7971 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7975 -- Mark the call as processed as a build-in-place call
7977 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7979 Loc := Sloc (Function_Call);
7981 if Is_Entity_Name (Name (Func_Call)) then
7982 Func_Id := Entity (Name (Func_Call));
7984 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7985 Func_Id := Etype (Name (Func_Call));
7988 raise Program_Error;
7991 Result_Subt := Etype (Func_Id);
7993 -- When the result subtype is unconstrained, an additional actual must
7994 -- be passed to indicate that the caller is providing the return object.
7995 -- This parameter must also be passed when the called function has a
7996 -- controlling result, because dispatching calls to the function needs
7997 -- to be treated effectively the same as calls to class-wide functions.
7999 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8000 (Func_Call, Func_Id, Alloc_Form => Caller_Allocation);
8002 Add_Finalization_Master_Actual_To_Build_In_Place_Call
8003 (Func_Call, Func_Id);
8005 Add_Task_Actuals_To_Build_In_Place_Call
8006 (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster));
8008 -- Add an implicit actual to the function call that provides access to
8009 -- the caller's return object.
8011 Add_Access_Actual_To_Build_In_Place_Call
8014 Make_Unchecked_Type_Conversion (Loc,
8015 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
8016 Expression => Relocate_Node (Lhs)));
8018 -- Create an access type designating the function's result subtype
8020 Ptr_Typ := Make_Temporary (Loc, 'A');
8023 Make_Full_Type_Declaration (Loc,
8024 Defining_Identifier => Ptr_Typ,
8026 Make_Access_To_Object_Definition (Loc,
8027 All_Present => True,
8028 Subtype_Indication =>
8029 New_Reference_To (Result_Subt, Loc)));
8030 Insert_After_And_Analyze (Assign, Ptr_Typ_Decl);
8032 -- Finally, create an access object initialized to a reference to the
8035 Obj_Id := Make_Temporary (Loc, 'R');
8036 Set_Etype (Obj_Id, Ptr_Typ);
8039 Make_Object_Declaration (Loc,
8040 Defining_Identifier => Obj_Id,
8041 Object_Definition => New_Reference_To (Ptr_Typ, Loc),
8042 Expression => Make_Reference (Loc, Relocate_Node (Func_Call)));
8043 Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl);
8045 Rewrite (Assign, Make_Null_Statement (Loc));
8047 -- Retrieve the target of the assignment
8049 if Nkind (Lhs) = N_Selected_Component then
8050 Target := Selector_Name (Lhs);
8051 elsif Nkind (Lhs) = N_Type_Conversion then
8052 Target := Expression (Lhs);
8057 -- If we are assigning to a return object or this is an expression of
8058 -- an extension aggregate, the target should either be an identifier
8059 -- or a simple expression. All other cases imply a different scenario.
8061 if Nkind (Target) in N_Has_Entity then
8062 Target := Entity (Target);
8066 end Make_Build_In_Place_Call_In_Assignment;
8068 ----------------------------------------------------
8069 -- Make_Build_In_Place_Call_In_Object_Declaration --
8070 ----------------------------------------------------
8072 procedure Make_Build_In_Place_Call_In_Object_Declaration
8073 (Object_Decl : Node_Id;
8074 Function_Call : Node_Id)
8077 Obj_Def_Id : constant Entity_Id :=
8078 Defining_Identifier (Object_Decl);
8079 Enclosing_Func : constant Entity_Id :=
8080 Enclosing_Subprogram (Obj_Def_Id);
8081 Call_Deref : Node_Id;
8082 Caller_Object : Node_Id;
8084 Fmaster_Actual : Node_Id := Empty;
8085 Func_Call : Node_Id := Function_Call;
8086 Function_Id : Entity_Id;
8087 Pool_Actual : Node_Id;
8088 Ptr_Typ_Decl : Node_Id;
8089 Pass_Caller_Acc : Boolean := False;
8091 Ref_Type : Entity_Id;
8092 Result_Subt : Entity_Id;
8095 -- Step past qualification or unchecked conversion (the latter can occur
8096 -- in cases of calls to 'Input).
8098 if Nkind_In (Func_Call, N_Qualified_Expression,
8099 N_Unchecked_Type_Conversion)
8101 Func_Call := Expression (Func_Call);
8104 -- If the call has already been processed to add build-in-place actuals
8105 -- then return. This should not normally occur in an object declaration,
8106 -- but we add the protection as a defensive measure.
8108 if Is_Expanded_Build_In_Place_Call (Func_Call) then
8112 -- Mark the call as processed as a build-in-place call
8114 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
8116 Loc := Sloc (Function_Call);
8118 if Is_Entity_Name (Name (Func_Call)) then
8119 Function_Id := Entity (Name (Func_Call));
8121 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
8122 Function_Id := Etype (Name (Func_Call));
8125 raise Program_Error;
8128 Result_Subt := Etype (Function_Id);
8130 -- If the the object is a return object of an enclosing build-in-place
8131 -- function, then the implicit build-in-place parameters of the
8132 -- enclosing function are simply passed along to the called function.
8133 -- (Unfortunately, this won't cover the case of extension aggregates
8134 -- where the ancestor part is a build-in-place unconstrained function
8135 -- call that should be passed along the caller's parameters. Currently
8136 -- those get mishandled by reassigning the result of the call to the
8137 -- aggregate return object, when the call result should really be
8138 -- directly built in place in the aggregate and not in a temporary. ???)
8140 if Is_Return_Object (Defining_Identifier (Object_Decl)) then
8141 Pass_Caller_Acc := True;
8143 -- When the enclosing function has a BIP_Alloc_Form formal then we
8144 -- pass it along to the callee (such as when the enclosing function
8145 -- has an unconstrained or tagged result type).
8147 if Needs_BIP_Alloc_Form (Enclosing_Func) then
8148 if VM_Target = No_VM and then
8149 RTE_Available (RE_Root_Storage_Pool_Ptr)
8152 New_Reference_To (Build_In_Place_Formal
8153 (Enclosing_Func, BIP_Storage_Pool), Loc);
8155 -- The build-in-place pool formal is not built on .NET/JVM
8158 Pool_Actual := Empty;
8161 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8166 (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form),
8168 Pool_Actual => Pool_Actual);
8170 -- Otherwise, if enclosing function has a constrained result subtype,
8171 -- then caller allocation will be used.
8174 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8175 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
8178 if Needs_BIP_Finalization_Master (Enclosing_Func) then
8181 (Build_In_Place_Formal
8182 (Enclosing_Func, BIP_Finalization_Master), Loc);
8185 -- Retrieve the BIPacc formal from the enclosing function and convert
8186 -- it to the access type of the callee's BIP_Object_Access formal.
8189 Make_Unchecked_Type_Conversion (Loc,
8193 (Build_In_Place_Formal (Function_Id, BIP_Object_Access)),
8197 (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access),
8200 -- In the constrained case, add an implicit actual to the function call
8201 -- that provides access to the declared object. An unchecked conversion
8202 -- to the (specific) result type of the function is inserted to handle
8203 -- the case where the object is declared with a class-wide type.
8205 elsif Is_Constrained (Underlying_Type (Result_Subt)) then
8207 Make_Unchecked_Type_Conversion (Loc,
8208 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
8209 Expression => New_Reference_To (Obj_Def_Id, Loc));
8211 -- When the function has a controlling result, an allocation-form
8212 -- parameter must be passed indicating that the caller is allocating
8213 -- the result object. This is needed because such a function can be
8214 -- called as a dispatching operation and must be treated similarly
8215 -- to functions with unconstrained result subtypes.
8217 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8218 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
8220 -- In other unconstrained cases, pass an indication to do the allocation
8221 -- on the secondary stack and set Caller_Object to Empty so that a null
8222 -- value will be passed for the caller's object address. A transient
8223 -- scope is established to ensure eventual cleanup of the result.
8226 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8227 (Func_Call, Function_Id, Alloc_Form => Secondary_Stack);
8228 Caller_Object := Empty;
8230 Establish_Transient_Scope (Object_Decl, Sec_Stack => True);
8233 -- Pass along any finalization master actual, which is needed in the
8234 -- case where the called function initializes a return object of an
8235 -- enclosing build-in-place function.
8237 Add_Finalization_Master_Actual_To_Build_In_Place_Call
8238 (Func_Call => Func_Call,
8239 Func_Id => Function_Id,
8240 Master_Exp => Fmaster_Actual);
8242 if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement
8243 and then Has_Task (Result_Subt)
8245 -- Here we're passing along the master that was passed in to this
8248 Add_Task_Actuals_To_Build_In_Place_Call
8249 (Func_Call, Function_Id,
8251 New_Reference_To (Build_In_Place_Formal
8252 (Enclosing_Func, BIP_Task_Master), Loc));
8255 Add_Task_Actuals_To_Build_In_Place_Call
8256 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
8259 Add_Access_Actual_To_Build_In_Place_Call
8260 (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc);
8262 -- Create an access type designating the function's result subtype. We
8263 -- use the type of the original expression because it may be a call to
8264 -- an inherited operation, which the expansion has replaced with the
8265 -- parent operation that yields the parent type.
8267 Ref_Type := Make_Temporary (Loc, 'A');
8270 Make_Full_Type_Declaration (Loc,
8271 Defining_Identifier => Ref_Type,
8273 Make_Access_To_Object_Definition (Loc,
8274 All_Present => True,
8275 Subtype_Indication =>
8276 New_Reference_To (Etype (Function_Call), Loc)));
8278 -- The access type and its accompanying object must be inserted after
8279 -- the object declaration in the constrained case, so that the function
8280 -- call can be passed access to the object. In the unconstrained case,
8281 -- or if the object declaration is for a return object, the access type
8282 -- and object must be inserted before the object, since the object
8283 -- declaration is rewritten to be a renaming of a dereference of the
8286 if Is_Constrained (Underlying_Type (Result_Subt))
8287 and then not Is_Return_Object (Defining_Identifier (Object_Decl))
8289 Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl);
8291 Insert_Action (Object_Decl, Ptr_Typ_Decl);
8294 -- Finally, create an access object initialized to a reference to the
8297 New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call));
8299 Def_Id := Make_Temporary (Loc, 'R', New_Expr);
8300 Set_Etype (Def_Id, Ref_Type);
8302 Insert_After_And_Analyze (Ptr_Typ_Decl,
8303 Make_Object_Declaration (Loc,
8304 Defining_Identifier => Def_Id,
8305 Object_Definition => New_Reference_To (Ref_Type, Loc),
8306 Expression => New_Expr));
8308 -- If the result subtype of the called function is constrained and
8309 -- is not itself the return expression of an enclosing BIP function,
8310 -- then mark the object as having no initialization.
8312 if Is_Constrained (Underlying_Type (Result_Subt))
8313 and then not Is_Return_Object (Defining_Identifier (Object_Decl))
8315 Set_Expression (Object_Decl, Empty);
8316 Set_No_Initialization (Object_Decl);
8318 -- In case of an unconstrained result subtype, or if the call is the
8319 -- return expression of an enclosing BIP function, rewrite the object
8320 -- declaration as an object renaming where the renamed object is a
8321 -- dereference of <function_Call>'reference:
8323 -- Obj : Subt renames <function_call>'Ref.all;
8327 Make_Explicit_Dereference (Loc,
8328 Prefix => New_Reference_To (Def_Id, Loc));
8330 Loc := Sloc (Object_Decl);
8331 Rewrite (Object_Decl,
8332 Make_Object_Renaming_Declaration (Loc,
8333 Defining_Identifier => Make_Temporary (Loc, 'D'),
8334 Access_Definition => Empty,
8335 Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc),
8336 Name => Call_Deref));
8338 Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref);
8340 Analyze (Object_Decl);
8342 -- Replace the internal identifier of the renaming declaration's
8343 -- entity with identifier of the original object entity. We also have
8344 -- to exchange the entities containing their defining identifiers to
8345 -- ensure the correct replacement of the object declaration by the
8346 -- object renaming declaration to avoid homograph conflicts (since
8347 -- the object declaration's defining identifier was already entered
8348 -- in current scope). The Next_Entity links of the two entities also
8349 -- have to be swapped since the entities are part of the return
8350 -- scope's entity list and the list structure would otherwise be
8351 -- corrupted. Finally, the homonym chain must be preserved as well.
8354 Renaming_Def_Id : constant Entity_Id :=
8355 Defining_Identifier (Object_Decl);
8356 Next_Entity_Temp : constant Entity_Id :=
8357 Next_Entity (Renaming_Def_Id);
8359 Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id));
8361 -- Swap next entity links in preparation for exchanging entities
8363 Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id));
8364 Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp);
8365 Set_Homonym (Renaming_Def_Id, Homonym (Obj_Def_Id));
8367 Exchange_Entities (Renaming_Def_Id, Obj_Def_Id);
8369 -- Preserve source indication of original declaration, so that
8370 -- xref information is properly generated for the right entity.
8372 Preserve_Comes_From_Source
8373 (Object_Decl, Original_Node (Object_Decl));
8375 Preserve_Comes_From_Source
8376 (Obj_Def_Id, Original_Node (Object_Decl));
8378 Set_Comes_From_Source (Renaming_Def_Id, False);
8382 -- If the object entity has a class-wide Etype, then we need to change
8383 -- it to the result subtype of the function call, because otherwise the
8384 -- object will be class-wide without an explicit initialization and
8385 -- won't be allocated properly by the back end. It seems unclean to make
8386 -- such a revision to the type at this point, and we should try to
8387 -- improve this treatment when build-in-place functions with class-wide
8388 -- results are implemented. ???
8390 if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then
8391 Set_Etype (Defining_Identifier (Object_Decl), Result_Subt);
8393 end Make_Build_In_Place_Call_In_Object_Declaration;
8395 -----------------------------------
8396 -- Needs_BIP_Finalization_Master --
8397 -----------------------------------
8399 function Needs_BIP_Finalization_Master
8400 (Func_Id : Entity_Id) return Boolean
8402 pragma Assert (Is_Build_In_Place_Function (Func_Id));
8403 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8406 not Restriction_Active (No_Finalization)
8407 and then Needs_Finalization (Func_Typ);
8408 end Needs_BIP_Finalization_Master;
8410 --------------------------
8411 -- Needs_BIP_Alloc_Form --
8412 --------------------------
8414 function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean is
8415 pragma Assert (Is_Build_In_Place_Function (Func_Id));
8416 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8418 return not Is_Constrained (Func_Typ) or else Is_Tagged_Type (Func_Typ);
8419 end Needs_BIP_Alloc_Form;
8421 --------------------------------------
8422 -- Needs_Result_Accessibility_Level --
8423 --------------------------------------
8425 function Needs_Result_Accessibility_Level
8426 (Func_Id : Entity_Id) return Boolean
8428 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8430 function Has_Unconstrained_Access_Discriminant_Component
8431 (Comp_Typ : Entity_Id) return Boolean;
8432 -- Returns True if any component of the type has an unconstrained access
8435 -----------------------------------------------------
8436 -- Has_Unconstrained_Access_Discriminant_Component --
8437 -----------------------------------------------------
8439 function Has_Unconstrained_Access_Discriminant_Component
8440 (Comp_Typ : Entity_Id) return Boolean
8443 if not Is_Limited_Type (Comp_Typ) then
8446 -- Only limited types can have access discriminants with
8449 elsif Has_Unconstrained_Access_Discriminants (Comp_Typ) then
8452 elsif Is_Array_Type (Comp_Typ) then
8453 return Has_Unconstrained_Access_Discriminant_Component
8454 (Underlying_Type (Component_Type (Comp_Typ)));
8456 elsif Is_Record_Type (Comp_Typ) then
8461 Comp := First_Component (Comp_Typ);
8462 while Present (Comp) loop
8463 if Has_Unconstrained_Access_Discriminant_Component
8464 (Underlying_Type (Etype (Comp)))
8469 Next_Component (Comp);
8475 end Has_Unconstrained_Access_Discriminant_Component;
8477 Feature_Disabled : constant Boolean := True;
8480 -- Start of processing for Needs_Result_Accessibility_Level
8483 -- False if completion unavailable (how does this happen???)
8485 if not Present (Func_Typ) then
8488 elsif Feature_Disabled then
8491 -- False if not a function, also handle enum-lit renames case
8493 elsif Func_Typ = Standard_Void_Type
8494 or else Is_Scalar_Type (Func_Typ)
8498 -- Handle a corner case, a cross-dialect subp renaming. For example,
8499 -- an Ada2012 renaming of an Ada05 subprogram. This can occur when a
8500 -- non-Ada2012 unit references predefined runtime units.
8502 elsif Present (Alias (Func_Id)) then
8504 -- Unimplemented: a cross-dialect subp renaming which does not set
8505 -- the Alias attribute (e.g., a rename of a dereference of an access
8506 -- to subprogram value). ???
8508 return Present (Extra_Accessibility_Of_Result (Alias (Func_Id)));
8510 -- Remaining cases require Ada 2012 mode
8512 elsif Ada_Version < Ada_2012 then
8515 elsif Ekind (Func_Typ) = E_Anonymous_Access_Type
8516 or else Is_Tagged_Type (Func_Typ)
8518 -- In the case of, say, a null tagged record result type, the need
8519 -- for this extra parameter might not be obvious. This function
8520 -- returns True for all tagged types for compatibility reasons.
8521 -- A function with, say, a tagged null controlling result type might
8522 -- be overridden by a primitive of an extension having an access
8523 -- discriminant and the overrider and overridden must have compatible
8524 -- calling conventions (including implicitly declared parameters).
8525 -- Similarly, values of one access-to-subprogram type might designate
8526 -- both a primitive subprogram of a given type and a function
8527 -- which is, for example, not a primitive subprogram of any type.
8528 -- Again, this requires calling convention compatibility.
8529 -- It might be possible to solve these issues by introducing
8530 -- wrappers, but that is not the approach that was chosen.
8534 elsif Has_Unconstrained_Access_Discriminants (Func_Typ) then
8537 elsif Has_Unconstrained_Access_Discriminant_Component (Func_Typ) then
8540 -- False for all other cases
8545 end Needs_Result_Accessibility_Level;