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 -- Cases where the call is not a member of a statement list
1755 if not Is_List_Member (N) then
1757 P : Node_Id := Parent (N);
1760 -- In Ada 2012 the call may be a function call in an expression
1761 -- (since OUT and IN OUT parameters are now allowed for such
1762 -- calls. The write-back of (in)-out parameters is handled
1763 -- by the back-end, but the constraint checks generated when
1764 -- subtypes of formal and actual don't match must be inserted
1765 -- in the form of assignments, at the nearest point after the
1766 -- declaration or statement that contains the call.
1768 if Ada_Version >= Ada_2012
1769 and then Nkind (N) = N_Function_Call
1771 while Nkind (P) not in N_Declaration
1773 Nkind (P) not in N_Statement_Other_Than_Procedure_Call
1778 Insert_Actions_After (P, Post_Call);
1780 -- If not the special Ada 2012 case of a function call, then
1781 -- we must have the triggering statement of a triggering
1782 -- alternative or an entry call alternative, and we can add
1783 -- the post call stuff to the corresponding statement list.
1786 pragma Assert (Nkind_In (P, N_Triggering_Alternative,
1787 N_Entry_Call_Alternative));
1789 if Is_Non_Empty_List (Statements (P)) then
1790 Insert_List_Before_And_Analyze
1791 (First (Statements (P)), Post_Call);
1793 Set_Statements (P, Post_Call);
1799 -- Otherwise, normal case where N is in a statement sequence,
1800 -- just put the post-call stuff after the call statement.
1803 Insert_Actions_After (N, Post_Call);
1807 -- The call node itself is re-analyzed in Expand_Call
1815 -- This procedure handles expansion of function calls and procedure call
1816 -- statements (i.e. it serves as the body for Expand_N_Function_Call and
1817 -- Expand_N_Procedure_Call_Statement). Processing for calls includes:
1819 -- Replace call to Raise_Exception by Raise_Exception_Always if possible
1820 -- Provide values of actuals for all formals in Extra_Formals list
1821 -- Replace "call" to enumeration literal function by literal itself
1822 -- Rewrite call to predefined operator as operator
1823 -- Replace actuals to in-out parameters that are numeric conversions,
1824 -- with explicit assignment to temporaries before and after the call.
1825 -- Remove optional actuals if First_Optional_Parameter specified.
1827 -- Note that the list of actuals has been filled with default expressions
1828 -- during semantic analysis of the call. Only the extra actuals required
1829 -- for the 'Constrained attribute and for accessibility checks are added
1832 procedure Expand_Call (N : Node_Id) is
1833 Loc : constant Source_Ptr := Sloc (N);
1834 Call_Node : Node_Id := N;
1835 Extra_Actuals : List_Id := No_List;
1836 Prev : Node_Id := Empty;
1838 procedure Add_Actual_Parameter (Insert_Param : Node_Id);
1839 -- Adds one entry to the end of the actual parameter list. Used for
1840 -- default parameters and for extra actuals (for Extra_Formals). The
1841 -- argument is an N_Parameter_Association node.
1843 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id);
1844 -- Adds an extra actual to the list of extra actuals. Expr is the
1845 -- expression for the value of the actual, EF is the entity for the
1848 function Inherited_From_Formal (S : Entity_Id) return Entity_Id;
1849 -- Within an instance, a type derived from a non-tagged formal derived
1850 -- type inherits from the original parent, not from the actual. The
1851 -- current derivation mechanism has the derived type inherit from the
1852 -- actual, which is only correct outside of the instance. If the
1853 -- subprogram is inherited, we test for this particular case through a
1854 -- convoluted tree traversal before setting the proper subprogram to be
1857 function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean;
1858 -- Determine if Subp denotes a non-dispatching call to a Deep routine
1860 function New_Value (From : Node_Id) return Node_Id;
1861 -- From is the original Expression. New_Value is equivalent to a call
1862 -- to Duplicate_Subexpr with an explicit dereference when From is an
1863 -- access parameter.
1865 --------------------------
1866 -- Add_Actual_Parameter --
1867 --------------------------
1869 procedure Add_Actual_Parameter (Insert_Param : Node_Id) is
1870 Actual_Expr : constant Node_Id :=
1871 Explicit_Actual_Parameter (Insert_Param);
1874 -- Case of insertion is first named actual
1876 if No (Prev) or else
1877 Nkind (Parent (Prev)) /= N_Parameter_Association
1879 Set_Next_Named_Actual
1880 (Insert_Param, First_Named_Actual (Call_Node));
1881 Set_First_Named_Actual (Call_Node, Actual_Expr);
1884 if No (Parameter_Associations (Call_Node)) then
1885 Set_Parameter_Associations (Call_Node, New_List);
1888 Append (Insert_Param, Parameter_Associations (Call_Node));
1891 Insert_After (Prev, Insert_Param);
1894 -- Case of insertion is not first named actual
1897 Set_Next_Named_Actual
1898 (Insert_Param, Next_Named_Actual (Parent (Prev)));
1899 Set_Next_Named_Actual (Parent (Prev), Actual_Expr);
1900 Append (Insert_Param, Parameter_Associations (Call_Node));
1903 Prev := Actual_Expr;
1904 end Add_Actual_Parameter;
1906 ----------------------
1907 -- Add_Extra_Actual --
1908 ----------------------
1910 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is
1911 Loc : constant Source_Ptr := Sloc (Expr);
1914 if Extra_Actuals = No_List then
1915 Extra_Actuals := New_List;
1916 Set_Parent (Extra_Actuals, Call_Node);
1919 Append_To (Extra_Actuals,
1920 Make_Parameter_Association (Loc,
1921 Selector_Name => Make_Identifier (Loc, Chars (EF)),
1922 Explicit_Actual_Parameter => Expr));
1924 Analyze_And_Resolve (Expr, Etype (EF));
1926 if Nkind (Call_Node) = N_Function_Call then
1927 Set_Is_Accessibility_Actual (Parent (Expr));
1929 end Add_Extra_Actual;
1931 ---------------------------
1932 -- Inherited_From_Formal --
1933 ---------------------------
1935 function Inherited_From_Formal (S : Entity_Id) return Entity_Id is
1937 Gen_Par : Entity_Id;
1938 Gen_Prim : Elist_Id;
1943 -- If the operation is inherited, it is attached to the corresponding
1944 -- type derivation. If the parent in the derivation is a generic
1945 -- actual, it is a subtype of the actual, and we have to recover the
1946 -- original derived type declaration to find the proper parent.
1948 if Nkind (Parent (S)) /= N_Full_Type_Declaration
1949 or else not Is_Derived_Type (Defining_Identifier (Parent (S)))
1950 or else Nkind (Type_Definition (Original_Node (Parent (S)))) /=
1951 N_Derived_Type_Definition
1952 or else not In_Instance
1959 (Type_Definition (Original_Node (Parent (S))));
1961 if Nkind (Indic) = N_Subtype_Indication then
1962 Par := Entity (Subtype_Mark (Indic));
1964 Par := Entity (Indic);
1968 if not Is_Generic_Actual_Type (Par)
1969 or else Is_Tagged_Type (Par)
1970 or else Nkind (Parent (Par)) /= N_Subtype_Declaration
1971 or else not In_Open_Scopes (Scope (Par))
1975 Gen_Par := Generic_Parent_Type (Parent (Par));
1978 -- If the actual has no generic parent type, the formal is not
1979 -- a formal derived type, so nothing to inherit.
1981 if No (Gen_Par) then
1985 -- If the generic parent type is still the generic type, this is a
1986 -- private formal, not a derived formal, and there are no operations
1987 -- inherited from the formal.
1989 if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then
1993 Gen_Prim := Collect_Primitive_Operations (Gen_Par);
1995 Elmt := First_Elmt (Gen_Prim);
1996 while Present (Elmt) loop
1997 if Chars (Node (Elmt)) = Chars (S) then
2003 F1 := First_Formal (S);
2004 F2 := First_Formal (Node (Elmt));
2006 and then Present (F2)
2008 if Etype (F1) = Etype (F2)
2009 or else Etype (F2) = Gen_Par
2015 exit; -- not the right subprogram
2027 raise Program_Error;
2028 end Inherited_From_Formal;
2030 -------------------------
2031 -- Is_Direct_Deep_Call --
2032 -------------------------
2034 function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean is
2036 if Is_TSS (Subp, TSS_Deep_Adjust)
2037 or else Is_TSS (Subp, TSS_Deep_Finalize)
2038 or else Is_TSS (Subp, TSS_Deep_Initialize)
2045 Actual := First (Parameter_Associations (N));
2046 Formal := First_Formal (Subp);
2047 while Present (Actual)
2048 and then Present (Formal)
2050 if Nkind (Actual) = N_Identifier
2051 and then Is_Controlling_Actual (Actual)
2052 and then Etype (Actual) = Etype (Formal)
2058 Next_Formal (Formal);
2064 end Is_Direct_Deep_Call;
2070 function New_Value (From : Node_Id) return Node_Id is
2071 Res : constant Node_Id := Duplicate_Subexpr (From);
2073 if Is_Access_Type (Etype (From)) then
2075 Make_Explicit_Dereference (Sloc (From),
2084 Curr_S : constant Entity_Id := Current_Scope;
2085 Remote : constant Boolean := Is_Remote_Call (Call_Node);
2088 Orig_Subp : Entity_Id := Empty;
2089 Param_Count : Natural := 0;
2090 Parent_Formal : Entity_Id;
2091 Parent_Subp : Entity_Id;
2095 Prev_Orig : Node_Id;
2096 -- Original node for an actual, which may have been rewritten. If the
2097 -- actual is a function call that has been transformed from a selected
2098 -- component, the original node is unanalyzed. Otherwise, it carries
2099 -- semantic information used to generate additional actuals.
2101 CW_Interface_Formals_Present : Boolean := False;
2103 -- Start of processing for Expand_Call
2106 -- Ignore if previous error
2108 if Nkind (Call_Node) in N_Has_Etype
2109 and then Etype (Call_Node) = Any_Type
2114 -- Call using access to subprogram with explicit dereference
2116 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
2117 Subp := Etype (Name (Call_Node));
2118 Parent_Subp := Empty;
2120 -- Case of call to simple entry, where the Name is a selected component
2121 -- whose prefix is the task, and whose selector name is the entry name
2123 elsif Nkind (Name (Call_Node)) = N_Selected_Component then
2124 Subp := Entity (Selector_Name (Name (Call_Node)));
2125 Parent_Subp := Empty;
2127 -- Case of call to member of entry family, where Name is an indexed
2128 -- component, with the prefix being a selected component giving the
2129 -- task and entry family name, and the index being the entry index.
2131 elsif Nkind (Name (Call_Node)) = N_Indexed_Component then
2132 Subp := Entity (Selector_Name (Prefix (Name (Call_Node))));
2133 Parent_Subp := Empty;
2138 Subp := Entity (Name (Call_Node));
2139 Parent_Subp := Alias (Subp);
2141 -- Replace call to Raise_Exception by call to Raise_Exception_Always
2142 -- if we can tell that the first parameter cannot possibly be null.
2143 -- This improves efficiency by avoiding a run-time test.
2145 -- We do not do this if Raise_Exception_Always does not exist, which
2146 -- can happen in configurable run time profiles which provide only a
2149 if Is_RTE (Subp, RE_Raise_Exception)
2150 and then RTE_Available (RE_Raise_Exception_Always)
2153 FA : constant Node_Id :=
2154 Original_Node (First_Actual (Call_Node));
2157 -- The case we catch is where the first argument is obtained
2158 -- using the Identity attribute (which must always be
2161 if Nkind (FA) = N_Attribute_Reference
2162 and then Attribute_Name (FA) = Name_Identity
2164 Subp := RTE (RE_Raise_Exception_Always);
2165 Set_Name (Call_Node, New_Occurrence_Of (Subp, Loc));
2170 if Ekind (Subp) = E_Entry then
2171 Parent_Subp := Empty;
2175 -- Detect the following code in System.Finalization_Masters only on
2176 -- .NET/JVM targets:
2178 -- procedure Finalize (Master : in out Finalization_Master) is
2182 -- Finalize (Curr_Ptr.all);
2184 -- Since .NET/JVM compilers lack address arithmetic and Deep_Finalize
2185 -- cannot be named in library or user code, the compiler has to install
2186 -- a kludge and transform the call to Finalize into Deep_Finalize.
2188 if VM_Target /= No_VM
2189 and then Chars (Subp) = Name_Finalize
2190 and then Ekind (Curr_S) = E_Block
2191 and then Ekind (Scope (Curr_S)) = E_Procedure
2192 and then Chars (Scope (Curr_S)) = Name_Finalize
2193 and then Etype (First_Formal (Scope (Curr_S))) =
2194 RTE (RE_Finalization_Master)
2197 Deep_Fin : constant Entity_Id :=
2198 Find_Prim_Op (RTE (RE_Root_Controlled),
2201 -- Since Root_Controlled is a tagged type, the compiler should
2202 -- always generate Deep_Finalize for it.
2204 pragma Assert (Present (Deep_Fin));
2207 -- Deep_Finalize (Curr_Ptr.all);
2210 Make_Procedure_Call_Statement (Loc,
2212 New_Reference_To (Deep_Fin, Loc),
2213 Parameter_Associations =>
2214 New_Copy_List_Tree (Parameter_Associations (N))));
2221 -- Ada 2005 (AI-345): We have a procedure call as a triggering
2222 -- alternative in an asynchronous select or as an entry call in
2223 -- a conditional or timed select. Check whether the procedure call
2224 -- is a renaming of an entry and rewrite it as an entry call.
2226 if Ada_Version >= Ada_2005
2227 and then Nkind (Call_Node) = N_Procedure_Call_Statement
2229 ((Nkind (Parent (Call_Node)) = N_Triggering_Alternative
2230 and then Triggering_Statement (Parent (Call_Node)) = Call_Node)
2232 (Nkind (Parent (Call_Node)) = N_Entry_Call_Alternative
2233 and then Entry_Call_Statement (Parent (Call_Node)) = Call_Node))
2237 Ren_Root : Entity_Id := Subp;
2240 -- This may be a chain of renamings, find the root
2242 if Present (Alias (Ren_Root)) then
2243 Ren_Root := Alias (Ren_Root);
2246 if Present (Original_Node (Parent (Parent (Ren_Root)))) then
2247 Ren_Decl := Original_Node (Parent (Parent (Ren_Root)));
2249 if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then
2251 Make_Entry_Call_Statement (Loc,
2253 New_Copy_Tree (Name (Ren_Decl)),
2254 Parameter_Associations =>
2256 (Parameter_Associations (Call_Node))));
2264 -- First step, compute extra actuals, corresponding to any Extra_Formals
2265 -- present. Note that we do not access Extra_Formals directly, instead
2266 -- we simply note the presence of the extra formals as we process the
2267 -- regular formals collecting corresponding actuals in Extra_Actuals.
2269 -- We also generate any required range checks for actuals for in formals
2270 -- as we go through the loop, since this is a convenient place to do it.
2271 -- (Though it seems that this would be better done in Expand_Actuals???)
2273 Formal := First_Formal (Subp);
2274 Actual := First_Actual (Call_Node);
2276 while Present (Formal) loop
2278 -- Generate range check if required
2280 if Do_Range_Check (Actual)
2281 and then Ekind (Formal) = E_In_Parameter
2283 Set_Do_Range_Check (Actual, False);
2284 Generate_Range_Check
2285 (Actual, Etype (Formal), CE_Range_Check_Failed);
2288 -- Prepare to examine current entry
2291 Prev_Orig := Original_Node (Prev);
2293 -- Ada 2005 (AI-251): Check if any formal is a class-wide interface
2294 -- to expand it in a further round.
2296 CW_Interface_Formals_Present :=
2297 CW_Interface_Formals_Present
2299 (Ekind (Etype (Formal)) = E_Class_Wide_Type
2300 and then Is_Interface (Etype (Etype (Formal))))
2302 (Ekind (Etype (Formal)) = E_Anonymous_Access_Type
2303 and then Is_Interface (Directly_Designated_Type
2304 (Etype (Etype (Formal)))));
2306 -- Create possible extra actual for constrained case. Usually, the
2307 -- extra actual is of the form actual'constrained, but since this
2308 -- attribute is only available for unconstrained records, TRUE is
2309 -- expanded if the type of the formal happens to be constrained (for
2310 -- instance when this procedure is inherited from an unconstrained
2311 -- record to a constrained one) or if the actual has no discriminant
2312 -- (its type is constrained). An exception to this is the case of a
2313 -- private type without discriminants. In this case we pass FALSE
2314 -- because the object has underlying discriminants with defaults.
2316 if Present (Extra_Constrained (Formal)) then
2317 if Ekind (Etype (Prev)) in Private_Kind
2318 and then not Has_Discriminants (Base_Type (Etype (Prev)))
2321 (New_Occurrence_Of (Standard_False, Loc),
2322 Extra_Constrained (Formal));
2324 elsif Is_Constrained (Etype (Formal))
2325 or else not Has_Discriminants (Etype (Prev))
2328 (New_Occurrence_Of (Standard_True, Loc),
2329 Extra_Constrained (Formal));
2331 -- Do not produce extra actuals for Unchecked_Union parameters.
2332 -- Jump directly to the end of the loop.
2334 elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then
2335 goto Skip_Extra_Actual_Generation;
2338 -- If the actual is a type conversion, then the constrained
2339 -- test applies to the actual, not the target type.
2345 -- Test for unchecked conversions as well, which can occur
2346 -- as out parameter actuals on calls to stream procedures.
2349 while Nkind_In (Act_Prev, N_Type_Conversion,
2350 N_Unchecked_Type_Conversion)
2352 Act_Prev := Expression (Act_Prev);
2355 -- If the expression is a conversion of a dereference, this
2356 -- is internally generated code that manipulates addresses,
2357 -- e.g. when building interface tables. No check should
2358 -- occur in this case, and the discriminated object is not
2361 if not Comes_From_Source (Actual)
2362 and then Nkind (Actual) = N_Unchecked_Type_Conversion
2363 and then Nkind (Act_Prev) = N_Explicit_Dereference
2366 (New_Occurrence_Of (Standard_False, Loc),
2367 Extra_Constrained (Formal));
2371 (Make_Attribute_Reference (Sloc (Prev),
2373 Duplicate_Subexpr_No_Checks
2374 (Act_Prev, Name_Req => True),
2375 Attribute_Name => Name_Constrained),
2376 Extra_Constrained (Formal));
2382 -- Create possible extra actual for accessibility level
2384 if Present (Extra_Accessibility (Formal)) then
2386 -- Ada 2005 (AI-252): If the actual was rewritten as an Access
2387 -- attribute, then the original actual may be an aliased object
2388 -- occurring as the prefix in a call using "Object.Operation"
2389 -- notation. In that case we must pass the level of the object,
2390 -- so Prev_Orig is reset to Prev and the attribute will be
2391 -- processed by the code for Access attributes further below.
2393 if Prev_Orig /= Prev
2394 and then Nkind (Prev) = N_Attribute_Reference
2396 Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access
2397 and then Is_Aliased_View (Prev_Orig)
2402 -- Ada 2005 (AI-251): Thunks must propagate the extra actuals of
2403 -- accessibility levels.
2405 if Ekind (Current_Scope) in Subprogram_Kind
2406 and then Is_Thunk (Current_Scope)
2409 Parm_Ent : Entity_Id;
2412 if Is_Controlling_Actual (Actual) then
2414 -- Find the corresponding actual of the thunk
2416 Parm_Ent := First_Entity (Current_Scope);
2417 for J in 2 .. Param_Count loop
2418 Next_Entity (Parm_Ent);
2421 else pragma Assert (Is_Entity_Name (Actual));
2422 Parm_Ent := Entity (Actual);
2426 (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc),
2427 Extra_Accessibility (Formal));
2430 elsif Is_Entity_Name (Prev_Orig) then
2432 -- When passing an access parameter, or a renaming of an access
2433 -- parameter, as the actual to another access parameter we need
2434 -- to pass along the actual's own access level parameter. This
2435 -- is done if we are within the scope of the formal access
2436 -- parameter (if this is an inlined body the extra formal is
2439 if (Is_Formal (Entity (Prev_Orig))
2441 (Present (Renamed_Object (Entity (Prev_Orig)))
2443 Is_Entity_Name (Renamed_Object (Entity (Prev_Orig)))
2446 (Entity (Renamed_Object (Entity (Prev_Orig))))))
2447 and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type
2448 and then In_Open_Scopes (Scope (Entity (Prev_Orig)))
2451 Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig);
2454 pragma Assert (Present (Parm_Ent));
2456 if Present (Extra_Accessibility (Parm_Ent)) then
2459 (Extra_Accessibility (Parm_Ent), Loc),
2460 Extra_Accessibility (Formal));
2462 -- If the actual access parameter does not have an
2463 -- associated extra formal providing its scope level,
2464 -- then treat the actual as having library-level
2469 (Make_Integer_Literal (Loc,
2470 Intval => Scope_Depth (Standard_Standard)),
2471 Extra_Accessibility (Formal));
2475 -- The actual is a normal access value, so just pass the level
2476 -- of the actual's access type.
2480 (Dynamic_Accessibility_Level (Prev_Orig),
2481 Extra_Accessibility (Formal));
2484 -- If the actual is an access discriminant, then pass the level
2485 -- of the enclosing object (RM05-3.10.2(12.4/2)).
2487 elsif Nkind (Prev_Orig) = N_Selected_Component
2488 and then Ekind (Entity (Selector_Name (Prev_Orig))) =
2490 and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) =
2491 E_Anonymous_Access_Type
2494 (Make_Integer_Literal (Loc,
2495 Intval => Object_Access_Level (Prefix (Prev_Orig))),
2496 Extra_Accessibility (Formal));
2501 case Nkind (Prev_Orig) is
2503 when N_Attribute_Reference =>
2504 case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is
2506 -- For X'Access, pass on the level of the prefix X
2508 when Attribute_Access =>
2510 -- If this is an Access attribute applied to the
2511 -- the current instance object passed to a type
2512 -- initialization procedure, then use the level
2513 -- of the type itself. This is not really correct,
2514 -- as there should be an extra level parameter
2515 -- passed in with _init formals (only in the case
2516 -- where the type is immutably limited), but we
2517 -- don't have an easy way currently to create such
2518 -- an extra formal (init procs aren't ever frozen).
2519 -- For now we just use the level of the type,
2520 -- which may be too shallow, but that works better
2521 -- than passing Object_Access_Level of the type,
2522 -- which can be one level too deep in some cases.
2525 if Is_Entity_Name (Prefix (Prev_Orig))
2526 and then Is_Type (Entity (Prefix (Prev_Orig)))
2529 (Make_Integer_Literal (Loc,
2532 (Entity (Prefix (Prev_Orig)))),
2533 Extra_Accessibility (Formal));
2537 (Make_Integer_Literal (Loc,
2540 (Prefix (Prev_Orig))),
2541 Extra_Accessibility (Formal));
2544 -- Treat the unchecked attributes as library-level
2546 when Attribute_Unchecked_Access |
2547 Attribute_Unrestricted_Access =>
2549 (Make_Integer_Literal (Loc,
2550 Intval => Scope_Depth (Standard_Standard)),
2551 Extra_Accessibility (Formal));
2553 -- No other cases of attributes returning access
2554 -- values that can be passed to access parameters.
2557 raise Program_Error;
2561 -- For allocators we pass the level of the execution of the
2562 -- called subprogram, which is one greater than the current
2567 (Make_Integer_Literal (Loc,
2568 Intval => Scope_Depth (Current_Scope) + 1),
2569 Extra_Accessibility (Formal));
2571 -- For most other cases we simply pass the level of the
2572 -- actual's access type. The type is retrieved from
2573 -- Prev rather than Prev_Orig, because in some cases
2574 -- Prev_Orig denotes an original expression that has
2575 -- not been analyzed.
2579 (Dynamic_Accessibility_Level (Prev),
2580 Extra_Accessibility (Formal));
2585 -- Perform the check of 4.6(49) that prevents a null value from being
2586 -- passed as an actual to an access parameter. Note that the check
2587 -- is elided in the common cases of passing an access attribute or
2588 -- access parameter as an actual. Also, we currently don't enforce
2589 -- this check for expander-generated actuals and when -gnatdj is set.
2591 if Ada_Version >= Ada_2005 then
2593 -- Ada 2005 (AI-231): Check null-excluding access types. Note that
2594 -- the intent of 6.4.1(13) is that null-exclusion checks should
2595 -- not be done for 'out' parameters, even though it refers only
2596 -- to constraint checks, and a null_exclusion is not a constraint.
2597 -- Note that AI05-0196-1 corrects this mistake in the RM.
2599 if Is_Access_Type (Etype (Formal))
2600 and then Can_Never_Be_Null (Etype (Formal))
2601 and then Ekind (Formal) /= E_Out_Parameter
2602 and then Nkind (Prev) /= N_Raise_Constraint_Error
2603 and then (Known_Null (Prev)
2604 or else not Can_Never_Be_Null (Etype (Prev)))
2606 Install_Null_Excluding_Check (Prev);
2609 -- Ada_Version < Ada_2005
2612 if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type
2613 or else Access_Checks_Suppressed (Subp)
2617 elsif Debug_Flag_J then
2620 elsif not Comes_From_Source (Prev) then
2623 elsif Is_Entity_Name (Prev)
2624 and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type
2628 elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then
2631 -- Suppress null checks when passing to access parameters of Java
2632 -- and CIL subprograms. (Should this be done for other foreign
2633 -- conventions as well ???)
2635 elsif Convention (Subp) = Convention_Java
2636 or else Convention (Subp) = Convention_CIL
2641 Install_Null_Excluding_Check (Prev);
2645 -- Perform appropriate validity checks on parameters that
2648 if Validity_Checks_On then
2649 if (Ekind (Formal) = E_In_Parameter
2650 and then Validity_Check_In_Params)
2652 (Ekind (Formal) = E_In_Out_Parameter
2653 and then Validity_Check_In_Out_Params)
2655 -- If the actual is an indexed component of a packed type (or
2656 -- is an indexed or selected component whose prefix recursively
2657 -- meets this condition), it has not been expanded yet. It will
2658 -- be copied in the validity code that follows, and has to be
2659 -- expanded appropriately, so reanalyze it.
2661 -- What we do is just to unset analyzed bits on prefixes till
2662 -- we reach something that does not have a prefix.
2669 while Nkind_In (Nod, N_Indexed_Component,
2670 N_Selected_Component)
2672 Set_Analyzed (Nod, False);
2673 Nod := Prefix (Nod);
2677 Ensure_Valid (Actual);
2681 -- For Ada 2012, if a parameter is aliased, the actual must be a
2682 -- tagged type or an aliased view of an object.
2684 if Is_Aliased (Formal)
2685 and then not Is_Aliased_View (Actual)
2686 and then not Is_Tagged_Type (Etype (Formal))
2689 ("actual for aliased formal& must be aliased object",
2693 -- For IN OUT and OUT parameters, ensure that subscripts are valid
2694 -- since this is a left side reference. We only do this for calls
2695 -- from the source program since we assume that compiler generated
2696 -- calls explicitly generate any required checks. We also need it
2697 -- only if we are doing standard validity checks, since clearly it is
2698 -- not needed if validity checks are off, and in subscript validity
2699 -- checking mode, all indexed components are checked with a call
2700 -- directly from Expand_N_Indexed_Component.
2702 if Comes_From_Source (Call_Node)
2703 and then Ekind (Formal) /= E_In_Parameter
2704 and then Validity_Checks_On
2705 and then Validity_Check_Default
2706 and then not Validity_Check_Subscripts
2708 Check_Valid_Lvalue_Subscripts (Actual);
2711 -- Mark any scalar OUT parameter that is a simple variable as no
2712 -- longer known to be valid (unless the type is always valid). This
2713 -- reflects the fact that if an OUT parameter is never set in a
2714 -- procedure, then it can become invalid on the procedure return.
2716 if Ekind (Formal) = E_Out_Parameter
2717 and then Is_Entity_Name (Actual)
2718 and then Ekind (Entity (Actual)) = E_Variable
2719 and then not Is_Known_Valid (Etype (Actual))
2721 Set_Is_Known_Valid (Entity (Actual), False);
2724 -- For an OUT or IN OUT parameter, if the actual is an entity, then
2725 -- clear current values, since they can be clobbered. We are probably
2726 -- doing this in more places than we need to, but better safe than
2727 -- sorry when it comes to retaining bad current values!
2729 if Ekind (Formal) /= E_In_Parameter
2730 and then Is_Entity_Name (Actual)
2731 and then Present (Entity (Actual))
2734 Ent : constant Entity_Id := Entity (Actual);
2738 -- For an OUT or IN OUT parameter that is an assignable entity,
2739 -- we do not want to clobber the Last_Assignment field, since
2740 -- if it is set, it was precisely because it is indeed an OUT
2741 -- or IN OUT parameter! We do reset the Is_Known_Valid flag
2742 -- since the subprogram could have returned in invalid value.
2744 if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter)
2745 and then Is_Assignable (Ent)
2747 Sav := Last_Assignment (Ent);
2748 Kill_Current_Values (Ent);
2749 Set_Last_Assignment (Ent, Sav);
2750 Set_Is_Known_Valid (Ent, False);
2752 -- For all other cases, just kill the current values
2755 Kill_Current_Values (Ent);
2760 -- If the formal is class wide and the actual is an aggregate, force
2761 -- evaluation so that the back end who does not know about class-wide
2762 -- type, does not generate a temporary of the wrong size.
2764 if not Is_Class_Wide_Type (Etype (Formal)) then
2767 elsif Nkind (Actual) = N_Aggregate
2768 or else (Nkind (Actual) = N_Qualified_Expression
2769 and then Nkind (Expression (Actual)) = N_Aggregate)
2771 Force_Evaluation (Actual);
2774 -- In a remote call, if the formal is of a class-wide type, check
2775 -- that the actual meets the requirements described in E.4(18).
2777 if Remote and then Is_Class_Wide_Type (Etype (Formal)) then
2778 Insert_Action (Actual,
2779 Make_Transportable_Check (Loc,
2780 Duplicate_Subexpr_Move_Checks (Actual)));
2783 -- This label is required when skipping extra actual generation for
2784 -- Unchecked_Union parameters.
2786 <<Skip_Extra_Actual_Generation>>
2788 Param_Count := Param_Count + 1;
2789 Next_Actual (Actual);
2790 Next_Formal (Formal);
2793 -- If we are calling an Ada 2012 function which needs to have the
2794 -- "accessibility level determined by the point of call" (AI05-0234)
2795 -- passed in to it, then pass it in.
2797 if Ekind_In (Subp, E_Function, E_Operator, E_Subprogram_Type)
2799 Present (Extra_Accessibility_Of_Result (Ultimate_Alias (Subp)))
2802 Ancestor : Node_Id := Parent (Call_Node);
2803 Level : Node_Id := Empty;
2804 Defer : Boolean := False;
2807 -- Unimplemented: if Subp returns an anonymous access type, then
2809 -- a) if the call is the operand of an explict conversion, then
2810 -- the target type of the conversion (a named access type)
2811 -- determines the accessibility level pass in;
2813 -- b) if the call defines an access discriminant of an object
2814 -- (e.g., the discriminant of an object being created by an
2815 -- allocator, or the discriminant of a function result),
2816 -- then the accessibility level to pass in is that of the
2817 -- discriminated object being initialized).
2821 while Nkind (Ancestor) = N_Qualified_Expression
2823 Ancestor := Parent (Ancestor);
2826 case Nkind (Ancestor) is
2829 -- At this point, we'd like to assign
2831 -- Level := Dynamic_Accessibility_Level (Ancestor);
2833 -- but Etype of Ancestor may not have been set yet,
2834 -- so that doesn't work.
2836 -- Handle this later in Expand_Allocator_Expression.
2840 when N_Object_Declaration | N_Object_Renaming_Declaration =>
2842 Def_Id : constant Entity_Id :=
2843 Defining_Identifier (Ancestor);
2846 if Is_Return_Object (Def_Id) then
2847 if Present (Extra_Accessibility_Of_Result
2848 (Return_Applies_To (Scope (Def_Id))))
2850 -- Pass along value that was passed in if the
2851 -- routine we are returning from also has an
2852 -- Accessibility_Of_Result formal.
2856 (Extra_Accessibility_Of_Result
2857 (Return_Applies_To (Scope (Def_Id))), Loc);
2861 Make_Integer_Literal (Loc,
2862 Intval => Object_Access_Level (Def_Id));
2866 when N_Simple_Return_Statement =>
2867 if Present (Extra_Accessibility_Of_Result
2869 (Return_Statement_Entity (Ancestor))))
2871 -- Pass along value that was passed in if the routine
2872 -- we are returning from also has an
2873 -- Accessibility_Of_Result formal.
2877 (Extra_Accessibility_Of_Result
2879 (Return_Statement_Entity (Ancestor))), Loc);
2887 if not Present (Level) then
2889 -- The "innermost master that evaluates the function call".
2891 -- ??? - Should we use Integer'Last here instead in order
2892 -- to deal with (some of) the problems associated with
2893 -- calls to subps whose enclosing scope is unknown (e.g.,
2894 -- Anon_Access_To_Subp_Param.all)?
2896 Level := Make_Integer_Literal (Loc,
2897 Scope_Depth (Current_Scope) + 1);
2902 Extra_Accessibility_Of_Result (Ultimate_Alias (Subp)));
2907 -- If we are expanding a rhs of an assignment we need to check if tag
2908 -- propagation is needed. You might expect this processing to be in
2909 -- Analyze_Assignment but has to be done earlier (bottom-up) because the
2910 -- assignment might be transformed to a declaration for an unconstrained
2911 -- value if the expression is classwide.
2913 if Nkind (Call_Node) = N_Function_Call
2914 and then Is_Tag_Indeterminate (Call_Node)
2915 and then Is_Entity_Name (Name (Call_Node))
2918 Ass : Node_Id := Empty;
2921 if Nkind (Parent (Call_Node)) = N_Assignment_Statement then
2922 Ass := Parent (Call_Node);
2924 elsif Nkind (Parent (Call_Node)) = N_Qualified_Expression
2925 and then Nkind (Parent (Parent (Call_Node))) =
2926 N_Assignment_Statement
2928 Ass := Parent (Parent (Call_Node));
2930 elsif Nkind (Parent (Call_Node)) = N_Explicit_Dereference
2931 and then Nkind (Parent (Parent (Call_Node))) =
2932 N_Assignment_Statement
2934 Ass := Parent (Parent (Call_Node));
2938 and then Is_Class_Wide_Type (Etype (Name (Ass)))
2940 if Is_Access_Type (Etype (Call_Node)) then
2941 if Designated_Type (Etype (Call_Node)) /=
2942 Root_Type (Etype (Name (Ass)))
2945 ("tag-indeterminate expression "
2946 & " must have designated type& (RM 5.2 (6))",
2947 Call_Node, Root_Type (Etype (Name (Ass))));
2949 Propagate_Tag (Name (Ass), Call_Node);
2952 elsif Etype (Call_Node) /= Root_Type (Etype (Name (Ass))) then
2954 ("tag-indeterminate expression must have type&"
2956 Call_Node, Root_Type (Etype (Name (Ass))));
2959 Propagate_Tag (Name (Ass), Call_Node);
2962 -- The call will be rewritten as a dispatching call, and
2963 -- expanded as such.
2970 -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand
2971 -- it to point to the correct secondary virtual table
2973 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2974 and then CW_Interface_Formals_Present
2976 Expand_Interface_Actuals (Call_Node);
2979 -- Deals with Dispatch_Call if we still have a call, before expanding
2980 -- extra actuals since this will be done on the re-analysis of the
2981 -- dispatching call. Note that we do not try to shorten the actual list
2982 -- for a dispatching call, it would not make sense to do so. Expansion
2983 -- of dispatching calls is suppressed when VM_Target, because the VM
2984 -- back-ends directly handle the generation of dispatching calls and
2985 -- would have to undo any expansion to an indirect call.
2987 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2988 and then Present (Controlling_Argument (Call_Node))
2991 Call_Typ : constant Entity_Id := Etype (Call_Node);
2992 Typ : constant Entity_Id := Find_Dispatching_Type (Subp);
2993 Eq_Prim_Op : Entity_Id := Empty;
2996 Prev_Call : Node_Id;
2999 if not Is_Limited_Type (Typ) then
3000 Eq_Prim_Op := Find_Prim_Op (Typ, Name_Op_Eq);
3003 if Tagged_Type_Expansion then
3004 Expand_Dispatching_Call (Call_Node);
3006 -- The following return is worrisome. Is it really OK to skip
3007 -- all remaining processing in this procedure ???
3014 Apply_Tag_Checks (Call_Node);
3016 -- If this is a dispatching "=", we must first compare the
3017 -- tags so we generate: x.tag = y.tag and then x = y
3019 if Subp = Eq_Prim_Op then
3021 -- Mark the node as analyzed to avoid reanalizing this
3022 -- dispatching call (which would cause a never-ending loop)
3024 Prev_Call := Relocate_Node (Call_Node);
3025 Set_Analyzed (Prev_Call);
3027 Param := First_Actual (Call_Node);
3033 Make_Selected_Component (Loc,
3034 Prefix => New_Value (Param),
3036 New_Reference_To (First_Tag_Component (Typ),
3040 Make_Selected_Component (Loc,
3042 Unchecked_Convert_To (Typ,
3043 New_Value (Next_Actual (Param))),
3046 (First_Tag_Component (Typ), Loc))),
3047 Right_Opnd => Prev_Call);
3049 Rewrite (Call_Node, New_Call);
3052 (Call_Node, Call_Typ, Suppress => All_Checks);
3055 -- Expansion of a dispatching call results in an indirect call,
3056 -- which in turn causes current values to be killed (see
3057 -- Resolve_Call), so on VM targets we do the call here to
3058 -- ensure consistent warnings between VM and non-VM targets.
3060 Kill_Current_Values;
3063 -- If this is a dispatching "=" then we must update the reference
3064 -- to the call node because we generated:
3065 -- x.tag = y.tag and then x = y
3067 if Subp = Eq_Prim_Op then
3068 Call_Node := Right_Opnd (Call_Node);
3073 -- Similarly, expand calls to RCI subprograms on which pragma
3074 -- All_Calls_Remote applies. The rewriting will be reanalyzed
3075 -- later. Do this only when the call comes from source since we
3076 -- do not want such a rewriting to occur in expanded code.
3078 if Is_All_Remote_Call (Call_Node) then
3079 Expand_All_Calls_Remote_Subprogram_Call (Call_Node);
3081 -- Similarly, do not add extra actuals for an entry call whose entity
3082 -- is a protected procedure, or for an internal protected subprogram
3083 -- call, because it will be rewritten as a protected subprogram call
3084 -- and reanalyzed (see Expand_Protected_Subprogram_Call).
3086 elsif Is_Protected_Type (Scope (Subp))
3087 and then (Ekind (Subp) = E_Procedure
3088 or else Ekind (Subp) = E_Function)
3092 -- During that loop we gathered the extra actuals (the ones that
3093 -- correspond to Extra_Formals), so now they can be appended.
3096 while Is_Non_Empty_List (Extra_Actuals) loop
3097 Add_Actual_Parameter (Remove_Head (Extra_Actuals));
3101 -- At this point we have all the actuals, so this is the point at which
3102 -- the various expansion activities for actuals is carried out.
3104 Expand_Actuals (Call_Node, Subp);
3106 -- If the subprogram is a renaming, or if it is inherited, replace it in
3107 -- the call with the name of the actual subprogram being called. If this
3108 -- is a dispatching call, the run-time decides what to call. The Alias
3109 -- attribute does not apply to entries.
3111 if Nkind (Call_Node) /= N_Entry_Call_Statement
3112 and then No (Controlling_Argument (Call_Node))
3113 and then Present (Parent_Subp)
3114 and then not Is_Direct_Deep_Call (Subp)
3116 if Present (Inherited_From_Formal (Subp)) then
3117 Parent_Subp := Inherited_From_Formal (Subp);
3119 Parent_Subp := Ultimate_Alias (Parent_Subp);
3122 -- The below setting of Entity is suspect, see F109-018 discussion???
3124 Set_Entity (Name (Call_Node), Parent_Subp);
3126 if Is_Abstract_Subprogram (Parent_Subp)
3127 and then not In_Instance
3130 ("cannot call abstract subprogram &!",
3131 Name (Call_Node), Parent_Subp);
3134 -- Inspect all formals of derived subprogram Subp. Compare parameter
3135 -- types with the parent subprogram and check whether an actual may
3136 -- need a type conversion to the corresponding formal of the parent
3139 -- Not clear whether intrinsic subprograms need such conversions. ???
3141 if not Is_Intrinsic_Subprogram (Parent_Subp)
3142 or else Is_Generic_Instance (Parent_Subp)
3145 procedure Convert (Act : Node_Id; Typ : Entity_Id);
3146 -- Rewrite node Act as a type conversion of Act to Typ. Analyze
3147 -- and resolve the newly generated construct.
3153 procedure Convert (Act : Node_Id; Typ : Entity_Id) is
3155 Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act)));
3162 Actual_Typ : Entity_Id;
3163 Formal_Typ : Entity_Id;
3164 Parent_Typ : Entity_Id;
3167 Actual := First_Actual (Call_Node);
3168 Formal := First_Formal (Subp);
3169 Parent_Formal := First_Formal (Parent_Subp);
3170 while Present (Formal) loop
3171 Actual_Typ := Etype (Actual);
3172 Formal_Typ := Etype (Formal);
3173 Parent_Typ := Etype (Parent_Formal);
3175 -- For an IN parameter of a scalar type, the parent formal
3176 -- type and derived formal type differ or the parent formal
3177 -- type and actual type do not match statically.
3179 if Is_Scalar_Type (Formal_Typ)
3180 and then Ekind (Formal) = E_In_Parameter
3181 and then Formal_Typ /= Parent_Typ
3183 not Subtypes_Statically_Match (Parent_Typ, Actual_Typ)
3184 and then not Raises_Constraint_Error (Actual)
3186 Convert (Actual, Parent_Typ);
3187 Enable_Range_Check (Actual);
3189 -- If the actual has been marked as requiring a range
3190 -- check, then generate it here.
3192 if Do_Range_Check (Actual) then
3193 Set_Do_Range_Check (Actual, False);
3194 Generate_Range_Check
3195 (Actual, Etype (Formal), CE_Range_Check_Failed);
3198 -- For access types, the parent formal type and actual type
3201 elsif Is_Access_Type (Formal_Typ)
3202 and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ)
3204 if Ekind (Formal) /= E_In_Parameter then
3205 Convert (Actual, Parent_Typ);
3207 elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type
3208 and then Designated_Type (Parent_Typ) /=
3209 Designated_Type (Actual_Typ)
3210 and then not Is_Controlling_Formal (Formal)
3212 -- This unchecked conversion is not necessary unless
3213 -- inlining is enabled, because in that case the type
3214 -- mismatch may become visible in the body about to be
3218 Unchecked_Convert_To (Parent_Typ,
3219 Relocate_Node (Actual)));
3221 Resolve (Actual, Parent_Typ);
3224 -- For array and record types, the parent formal type and
3225 -- derived formal type have different sizes or pragma Pack
3228 elsif ((Is_Array_Type (Formal_Typ)
3229 and then Is_Array_Type (Parent_Typ))
3231 (Is_Record_Type (Formal_Typ)
3232 and then Is_Record_Type (Parent_Typ)))
3234 (Esize (Formal_Typ) /= Esize (Parent_Typ)
3235 or else Has_Pragma_Pack (Formal_Typ) /=
3236 Has_Pragma_Pack (Parent_Typ))
3238 Convert (Actual, Parent_Typ);
3241 Next_Actual (Actual);
3242 Next_Formal (Formal);
3243 Next_Formal (Parent_Formal);
3249 Subp := Parent_Subp;
3252 -- Check for violation of No_Abort_Statements
3254 if Restriction_Check_Required (No_Abort_Statements)
3255 and then Is_RTE (Subp, RE_Abort_Task)
3257 Check_Restriction (No_Abort_Statements, Call_Node);
3259 -- Check for violation of No_Dynamic_Attachment
3261 elsif Restriction_Check_Required (No_Dynamic_Attachment)
3262 and then RTU_Loaded (Ada_Interrupts)
3263 and then (Is_RTE (Subp, RE_Is_Reserved) or else
3264 Is_RTE (Subp, RE_Is_Attached) or else
3265 Is_RTE (Subp, RE_Current_Handler) or else
3266 Is_RTE (Subp, RE_Attach_Handler) or else
3267 Is_RTE (Subp, RE_Exchange_Handler) or else
3268 Is_RTE (Subp, RE_Detach_Handler) or else
3269 Is_RTE (Subp, RE_Reference))
3271 Check_Restriction (No_Dynamic_Attachment, Call_Node);
3274 -- Deal with case where call is an explicit dereference
3276 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
3278 -- Handle case of access to protected subprogram type
3280 if Is_Access_Protected_Subprogram_Type
3281 (Base_Type (Etype (Prefix (Name (Call_Node)))))
3283 -- If this is a call through an access to protected operation, the
3284 -- prefix has the form (object'address, operation'access). Rewrite
3285 -- as a for other protected calls: the object is the 1st parameter
3286 -- of the list of actuals.
3293 Ptr : constant Node_Id := Prefix (Name (Call_Node));
3295 T : constant Entity_Id :=
3296 Equivalent_Type (Base_Type (Etype (Ptr)));
3298 D_T : constant Entity_Id :=
3299 Designated_Type (Base_Type (Etype (Ptr)));
3303 Make_Selected_Component (Loc,
3304 Prefix => Unchecked_Convert_To (T, Ptr),
3306 New_Occurrence_Of (First_Entity (T), Loc));
3309 Make_Selected_Component (Loc,
3310 Prefix => Unchecked_Convert_To (T, Ptr),
3312 New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc));
3315 Make_Explicit_Dereference (Loc,
3318 if Present (Parameter_Associations (Call_Node)) then
3319 Parm := Parameter_Associations (Call_Node);
3324 Prepend (Obj, Parm);
3326 if Etype (D_T) = Standard_Void_Type then
3328 Make_Procedure_Call_Statement (Loc,
3330 Parameter_Associations => Parm);
3333 Make_Function_Call (Loc,
3335 Parameter_Associations => Parm);
3338 Set_First_Named_Actual (Call, First_Named_Actual (Call_Node));
3339 Set_Etype (Call, Etype (D_T));
3341 -- We do not re-analyze the call to avoid infinite recursion.
3342 -- We analyze separately the prefix and the object, and set
3343 -- the checks on the prefix that would otherwise be emitted
3344 -- when resolving a call.
3346 Rewrite (Call_Node, Call);
3348 Apply_Access_Check (Nam);
3355 -- If this is a call to an intrinsic subprogram, then perform the
3356 -- appropriate expansion to the corresponding tree node and we
3357 -- are all done (since after that the call is gone!)
3359 -- In the case where the intrinsic is to be processed by the back end,
3360 -- the call to Expand_Intrinsic_Call will do nothing, which is fine,
3361 -- since the idea in this case is to pass the call unchanged. If the
3362 -- intrinsic is an inherited unchecked conversion, and the derived type
3363 -- is the target type of the conversion, we must retain it as the return
3364 -- type of the expression. Otherwise the expansion below, which uses the
3365 -- parent operation, will yield the wrong type.
3367 if Is_Intrinsic_Subprogram (Subp) then
3368 Expand_Intrinsic_Call (Call_Node, Subp);
3370 if Nkind (Call_Node) = N_Unchecked_Type_Conversion
3371 and then Parent_Subp /= Orig_Subp
3372 and then Etype (Parent_Subp) /= Etype (Orig_Subp)
3374 Set_Etype (Call_Node, Etype (Orig_Subp));
3380 if Ekind_In (Subp, E_Function, E_Procedure) then
3382 -- We perform two simple optimization on calls:
3384 -- a) replace calls to null procedures unconditionally;
3386 -- b) for To_Address, just do an unchecked conversion. Not only is
3387 -- this efficient, but it also avoids order of elaboration problems
3388 -- when address clauses are inlined (address expression elaborated
3389 -- at the wrong point).
3391 -- We perform these optimization regardless of whether we are in the
3392 -- main unit or in a unit in the context of the main unit, to ensure
3393 -- that tree generated is the same in both cases, for Inspector use.
3395 if Is_RTE (Subp, RE_To_Address) then
3397 Unchecked_Convert_To
3398 (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node))));
3401 elsif Is_Null_Procedure (Subp) then
3402 Rewrite (Call_Node, Make_Null_Statement (Loc));
3406 if Is_Inlined (Subp) then
3408 Inlined_Subprogram : declare
3410 Must_Inline : Boolean := False;
3411 Spec : constant Node_Id := Unit_Declaration_Node (Subp);
3412 Scop : constant Entity_Id := Scope (Subp);
3414 function In_Unfrozen_Instance return Boolean;
3415 -- If the subprogram comes from an instance in the same unit,
3416 -- and the instance is not yet frozen, inlining might trigger
3417 -- order-of-elaboration problems in gigi.
3419 --------------------------
3420 -- In_Unfrozen_Instance --
3421 --------------------------
3423 function In_Unfrozen_Instance return Boolean is
3429 and then S /= Standard_Standard
3431 if Is_Generic_Instance (S)
3432 and then Present (Freeze_Node (S))
3433 and then not Analyzed (Freeze_Node (S))
3442 end In_Unfrozen_Instance;
3444 -- Start of processing for Inlined_Subprogram
3447 -- Verify that the body to inline has already been seen, and
3448 -- that if the body is in the current unit the inlining does
3449 -- not occur earlier. This avoids order-of-elaboration problems
3452 -- This should be documented in sinfo/einfo ???
3455 or else Nkind (Spec) /= N_Subprogram_Declaration
3456 or else No (Body_To_Inline (Spec))
3458 Must_Inline := False;
3460 -- If this an inherited function that returns a private type,
3461 -- do not inline if the full view is an unconstrained array,
3462 -- because such calls cannot be inlined.
3464 elsif Present (Orig_Subp)
3465 and then Is_Array_Type (Etype (Orig_Subp))
3466 and then not Is_Constrained (Etype (Orig_Subp))
3468 Must_Inline := False;
3470 elsif In_Unfrozen_Instance then
3471 Must_Inline := False;
3474 Bod := Body_To_Inline (Spec);
3476 if (In_Extended_Main_Code_Unit (Call_Node)
3477 or else In_Extended_Main_Code_Unit (Parent (Call_Node))
3478 or else Has_Pragma_Inline_Always (Subp))
3479 and then (not In_Same_Extended_Unit (Sloc (Bod), Loc)
3481 Earlier_In_Extended_Unit (Sloc (Bod), Loc))
3483 Must_Inline := True;
3485 -- If we are compiling a package body that is not the main
3486 -- unit, it must be for inlining/instantiation purposes,
3487 -- in which case we inline the call to insure that the same
3488 -- temporaries are generated when compiling the body by
3489 -- itself. Otherwise link errors can occur.
3491 -- If the function being called is itself in the main unit,
3492 -- we cannot inline, because there is a risk of double
3493 -- elaboration and/or circularity: the inlining can make
3494 -- visible a private entity in the body of the main unit,
3495 -- that gigi will see before its sees its proper definition.
3497 elsif not (In_Extended_Main_Code_Unit (Call_Node))
3498 and then In_Package_Body
3500 Must_Inline := not In_Extended_Main_Source_Unit (Subp);
3505 Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);
3508 -- Let the back end handle it
3510 Add_Inlined_Body (Subp);
3512 if Front_End_Inlining
3513 and then Nkind (Spec) = N_Subprogram_Declaration
3514 and then (In_Extended_Main_Code_Unit (Call_Node))
3515 and then No (Body_To_Inline (Spec))
3516 and then not Has_Completion (Subp)
3517 and then In_Same_Extended_Unit (Sloc (Spec), Loc)
3520 ("cannot inline& (body not seen yet)?", Call_Node, Subp);
3523 end Inlined_Subprogram;
3527 -- Check for protected subprogram. This is either an intra-object call,
3528 -- or a protected function call. Protected procedure calls are rewritten
3529 -- as entry calls and handled accordingly.
3531 -- In Ada 2005, this may be an indirect call to an access parameter that
3532 -- is an access_to_subprogram. In that case the anonymous type has a
3533 -- scope that is a protected operation, but the call is a regular one.
3534 -- In either case do not expand call if subprogram is eliminated.
3536 Scop := Scope (Subp);
3538 if Nkind (Call_Node) /= N_Entry_Call_Statement
3539 and then Is_Protected_Type (Scop)
3540 and then Ekind (Subp) /= E_Subprogram_Type
3541 and then not Is_Eliminated (Subp)
3543 -- If the call is an internal one, it is rewritten as a call to the
3544 -- corresponding unprotected subprogram.
3546 Expand_Protected_Subprogram_Call (Call_Node, Subp, Scop);
3549 -- Functions returning controlled objects need special attention. If
3550 -- the return type is limited, then the context is initialization and
3551 -- different processing applies. If the call is to a protected function,
3552 -- the expansion above will call Expand_Call recursively. Otherwise the
3553 -- function call is transformed into a temporary which obtains the
3554 -- result from the secondary stack.
3556 if Needs_Finalization (Etype (Subp)) then
3557 if not Is_Immutably_Limited_Type (Etype (Subp))
3559 (No (First_Formal (Subp))
3561 not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
3563 Expand_Ctrl_Function_Call (Call_Node);
3565 -- Build-in-place function calls which appear in anonymous contexts
3566 -- need a transient scope to ensure the proper finalization of the
3567 -- intermediate result after its use.
3569 elsif Is_Build_In_Place_Function_Call (Call_Node)
3570 and then Nkind_In (Parent (Call_Node), N_Attribute_Reference,
3572 N_Indexed_Component,
3573 N_Object_Renaming_Declaration,
3574 N_Procedure_Call_Statement,
3575 N_Selected_Component,
3578 Establish_Transient_Scope (Call_Node, Sec_Stack => True);
3582 -- Test for First_Optional_Parameter, and if so, truncate parameter list
3583 -- if there are optional parameters at the trailing end.
3584 -- Note: we never delete procedures for call via a pointer.
3586 if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function)
3587 and then Present (First_Optional_Parameter (Subp))
3590 Last_Keep_Arg : Node_Id;
3593 -- Last_Keep_Arg will hold the last actual that should be kept.
3594 -- If it remains empty at the end, it means that all parameters
3597 Last_Keep_Arg := Empty;
3599 -- Find first optional parameter, must be present since we checked
3600 -- the validity of the parameter before setting it.
3602 Formal := First_Formal (Subp);
3603 Actual := First_Actual (Call_Node);
3604 while Formal /= First_Optional_Parameter (Subp) loop
3605 Last_Keep_Arg := Actual;
3606 Next_Formal (Formal);
3607 Next_Actual (Actual);
3610 -- We have Formal and Actual pointing to the first potentially
3611 -- droppable argument. We can drop all the trailing arguments
3612 -- whose actual matches the default. Note that we know that all
3613 -- remaining formals have defaults, because we checked that this
3614 -- requirement was met before setting First_Optional_Parameter.
3616 -- We use Fully_Conformant_Expressions to check for identity
3617 -- between formals and actuals, which may miss some cases, but
3618 -- on the other hand, this is only an optimization (if we fail
3619 -- to truncate a parameter it does not affect functionality).
3620 -- So if the default is 3 and the actual is 1+2, we consider
3621 -- them unequal, which hardly seems worrisome.
3623 while Present (Formal) loop
3624 if not Fully_Conformant_Expressions
3625 (Actual, Default_Value (Formal))
3627 Last_Keep_Arg := Actual;
3630 Next_Formal (Formal);
3631 Next_Actual (Actual);
3634 -- If no arguments, delete entire list, this is the easy case
3636 if No (Last_Keep_Arg) then
3637 Set_Parameter_Associations (Call_Node, No_List);
3638 Set_First_Named_Actual (Call_Node, Empty);
3640 -- Case where at the last retained argument is positional. This
3641 -- is also an easy case, since the retained arguments are already
3642 -- in the right form, and we don't need to worry about the order
3643 -- of arguments that get eliminated.
3645 elsif Is_List_Member (Last_Keep_Arg) then
3646 while Present (Next (Last_Keep_Arg)) loop
3647 Discard_Node (Remove_Next (Last_Keep_Arg));
3650 Set_First_Named_Actual (Call_Node, Empty);
3652 -- This is the annoying case where the last retained argument
3653 -- is a named parameter. Since the original arguments are not
3654 -- in declaration order, we may have to delete some fairly
3655 -- random collection of arguments.
3663 -- First step, remove all the named parameters from the
3664 -- list (they are still chained using First_Named_Actual
3665 -- and Next_Named_Actual, so we have not lost them!)
3667 Temp := First (Parameter_Associations (Call_Node));
3669 -- Case of all parameters named, remove them all
3671 if Nkind (Temp) = N_Parameter_Association then
3672 -- Suppress warnings to avoid warning on possible
3673 -- infinite loop (because Call_Node is not modified).
3675 pragma Warnings (Off);
3676 while Is_Non_Empty_List
3677 (Parameter_Associations (Call_Node))
3680 Remove_Head (Parameter_Associations (Call_Node));
3682 pragma Warnings (On);
3684 -- Case of mixed positional/named, remove named parameters
3687 while Nkind (Next (Temp)) /= N_Parameter_Association loop
3691 while Present (Next (Temp)) loop
3692 Remove (Next (Temp));
3696 -- Now we loop through the named parameters, till we get
3697 -- to the last one to be retained, adding them to the list.
3698 -- Note that the Next_Named_Actual list does not need to be
3699 -- touched since we are only reordering them on the actual
3700 -- parameter association list.
3702 Passoc := Parent (First_Named_Actual (Call_Node));
3704 Temp := Relocate_Node (Passoc);
3706 (Parameter_Associations (Call_Node), Temp);
3708 Last_Keep_Arg = Explicit_Actual_Parameter (Passoc);
3709 Passoc := Parent (Next_Named_Actual (Passoc));
3712 Set_Next_Named_Actual (Temp, Empty);
3715 Temp := Next_Named_Actual (Passoc);
3716 exit when No (Temp);
3717 Set_Next_Named_Actual
3718 (Passoc, Next_Named_Actual (Parent (Temp)));
3727 -------------------------------
3728 -- Expand_Ctrl_Function_Call --
3729 -------------------------------
3731 procedure Expand_Ctrl_Function_Call (N : Node_Id) is
3733 -- Optimization, if the returned value (which is on the sec-stack) is
3734 -- returned again, no need to copy/readjust/finalize, we can just pass
3735 -- the value thru (see Expand_N_Simple_Return_Statement), and thus no
3736 -- attachment is needed
3738 if Nkind (Parent (N)) = N_Simple_Return_Statement then
3742 -- Resolution is now finished, make sure we don't start analysis again
3743 -- because of the duplication.
3747 -- A function which returns a controlled object uses the secondary
3748 -- stack. Rewrite the call into a temporary which obtains the result of
3749 -- the function using 'reference.
3751 Remove_Side_Effects (N);
3752 end Expand_Ctrl_Function_Call;
3754 --------------------------
3755 -- Expand_Inlined_Call --
3756 --------------------------
3758 procedure Expand_Inlined_Call
3761 Orig_Subp : Entity_Id)
3763 Loc : constant Source_Ptr := Sloc (N);
3764 Is_Predef : constant Boolean :=
3765 Is_Predefined_File_Name
3766 (Unit_File_Name (Get_Source_Unit (Subp)));
3767 Orig_Bod : constant Node_Id :=
3768 Body_To_Inline (Unit_Declaration_Node (Subp));
3773 Decls : constant List_Id := New_List;
3774 Exit_Lab : Entity_Id := Empty;
3781 Ret_Type : Entity_Id;
3784 -- The target of the call. If context is an assignment statement then
3785 -- this is the left-hand side of the assignment. else it is a temporary
3786 -- to which the return value is assigned prior to rewriting the call.
3789 -- A separate target used when the return type is unconstrained
3792 Temp_Typ : Entity_Id;
3794 Return_Object : Entity_Id := Empty;
3795 -- Entity in declaration in an extended_return_statement
3797 Is_Unc : constant Boolean :=
3798 Is_Array_Type (Etype (Subp))
3799 and then not Is_Constrained (Etype (Subp));
3800 -- If the type returned by the function is unconstrained and the call
3801 -- can be inlined, special processing is required.
3803 procedure Make_Exit_Label;
3804 -- Build declaration for exit label to be used in Return statements,
3805 -- sets Exit_Lab (the label node) and Lab_Decl (corresponding implicit
3806 -- declaration). Does nothing if Exit_Lab already set.
3808 function Process_Formals (N : Node_Id) return Traverse_Result;
3809 -- Replace occurrence of a formal with the corresponding actual, or the
3810 -- thunk generated for it.
3812 function Process_Sloc (Nod : Node_Id) return Traverse_Result;
3813 -- If the call being expanded is that of an internal subprogram, set the
3814 -- sloc of the generated block to that of the call itself, so that the
3815 -- expansion is skipped by the "next" command in gdb.
3816 -- Same processing for a subprogram in a predefined file, e.g.
3817 -- Ada.Tags. If Debug_Generated_Code is true, suppress this change to
3818 -- simplify our own development.
3820 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id);
3821 -- If the function body is a single expression, replace call with
3822 -- expression, else insert block appropriately.
3824 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id);
3825 -- If procedure body has no local variables, inline body without
3826 -- creating block, otherwise rewrite call with block.
3828 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean;
3829 -- Determine whether a formal parameter is used only once in Orig_Bod
3831 ---------------------
3832 -- Make_Exit_Label --
3833 ---------------------
3835 procedure Make_Exit_Label is
3836 Lab_Ent : Entity_Id;
3838 if No (Exit_Lab) then
3839 Lab_Ent := Make_Temporary (Loc, 'L');
3840 Lab_Id := New_Reference_To (Lab_Ent, Loc);
3841 Exit_Lab := Make_Label (Loc, Lab_Id);
3843 Make_Implicit_Label_Declaration (Loc,
3844 Defining_Identifier => Lab_Ent,
3845 Label_Construct => Exit_Lab);
3847 end Make_Exit_Label;
3849 ---------------------
3850 -- Process_Formals --
3851 ---------------------
3853 function Process_Formals (N : Node_Id) return Traverse_Result is
3859 if Is_Entity_Name (N)
3860 and then Present (Entity (N))
3865 and then Scope (E) = Subp
3867 A := Renamed_Object (E);
3869 -- Rewrite the occurrence of the formal into an occurrence of
3870 -- the actual. Also establish visibility on the proper view of
3871 -- the actual's subtype for the body's context (if the actual's
3872 -- subtype is private at the call point but its full view is
3873 -- visible to the body, then the inlined tree here must be
3874 -- analyzed with the full view).
3876 if Is_Entity_Name (A) then
3877 Rewrite (N, New_Occurrence_Of (Entity (A), Loc));
3878 Check_Private_View (N);
3880 elsif Nkind (A) = N_Defining_Identifier then
3881 Rewrite (N, New_Occurrence_Of (A, Loc));
3882 Check_Private_View (N);
3887 Rewrite (N, New_Copy (A));
3893 elsif Is_Entity_Name (N)
3894 and then Present (Return_Object)
3895 and then Chars (N) = Chars (Return_Object)
3897 -- Occurrence within an extended return statement. The return
3898 -- object is local to the body been inlined, and thus the generic
3899 -- copy is not analyzed yet, so we match by name, and replace it
3900 -- with target of call.
3902 if Nkind (Targ) = N_Defining_Identifier then
3903 Rewrite (N, New_Occurrence_Of (Targ, Loc));
3905 Rewrite (N, New_Copy_Tree (Targ));
3910 elsif Nkind (N) = N_Simple_Return_Statement then
3911 if No (Expression (N)) then
3914 Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id)));
3917 if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements
3918 and then Nkind (Parent (Parent (N))) = N_Subprogram_Body
3920 -- Function body is a single expression. No need for
3926 Num_Ret := Num_Ret + 1;
3930 -- Because of the presence of private types, the views of the
3931 -- expression and the context may be different, so place an
3932 -- unchecked conversion to the context type to avoid spurious
3933 -- errors, e.g. when the expression is a numeric literal and
3934 -- the context is private. If the expression is an aggregate,
3935 -- use a qualified expression, because an aggregate is not a
3936 -- legal argument of a conversion.
3938 if Nkind_In (Expression (N), N_Aggregate, N_Null) then
3940 Make_Qualified_Expression (Sloc (N),
3941 Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)),
3942 Expression => Relocate_Node (Expression (N)));
3945 Unchecked_Convert_To
3946 (Ret_Type, Relocate_Node (Expression (N)));
3949 if Nkind (Targ) = N_Defining_Identifier then
3951 Make_Assignment_Statement (Loc,
3952 Name => New_Occurrence_Of (Targ, Loc),
3953 Expression => Ret));
3956 Make_Assignment_Statement (Loc,
3957 Name => New_Copy (Targ),
3958 Expression => Ret));
3961 Set_Assignment_OK (Name (N));
3963 if Present (Exit_Lab) then
3965 Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id)));
3971 -- An extended return becomes a block whose first statement is the
3972 -- assignment of the initial expression of the return object to the
3973 -- target of the call itself.
3975 elsif Nkind (N) = N_Extended_Return_Statement then
3977 Return_Decl : constant Entity_Id :=
3978 First (Return_Object_Declarations (N));
3982 Return_Object := Defining_Identifier (Return_Decl);
3984 if Present (Expression (Return_Decl)) then
3985 if Nkind (Targ) = N_Defining_Identifier then
3987 Make_Assignment_Statement (Loc,
3988 Name => New_Occurrence_Of (Targ, Loc),
3989 Expression => Expression (Return_Decl));
3992 Make_Assignment_Statement (Loc,
3993 Name => New_Copy (Targ),
3994 Expression => Expression (Return_Decl));
3997 Set_Assignment_OK (Name (Assign));
3999 Statements (Handled_Statement_Sequence (N)));
4003 Make_Block_Statement (Loc,
4004 Handled_Statement_Sequence =>
4005 Handled_Statement_Sequence (N)));
4010 -- Remove pragma Unreferenced since it may refer to formals that
4011 -- are not visible in the inlined body, and in any case we will
4012 -- not be posting warnings on the inlined body so it is unneeded.
4014 elsif Nkind (N) = N_Pragma
4015 and then Pragma_Name (N) = Name_Unreferenced
4017 Rewrite (N, Make_Null_Statement (Sloc (N)));
4023 end Process_Formals;
4025 procedure Replace_Formals is new Traverse_Proc (Process_Formals);
4031 function Process_Sloc (Nod : Node_Id) return Traverse_Result is
4033 if not Debug_Generated_Code then
4034 Set_Sloc (Nod, Sloc (N));
4035 Set_Comes_From_Source (Nod, False);
4041 procedure Reset_Slocs is new Traverse_Proc (Process_Sloc);
4043 ---------------------------
4044 -- Rewrite_Function_Call --
4045 ---------------------------
4047 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is
4048 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
4049 Fst : constant Node_Id := First (Statements (HSS));
4052 -- Optimize simple case: function body is a single return statement,
4053 -- which has been expanded into an assignment.
4055 if Is_Empty_List (Declarations (Blk))
4056 and then Nkind (Fst) = N_Assignment_Statement
4057 and then No (Next (Fst))
4059 -- The function call may have been rewritten as the temporary
4060 -- that holds the result of the call, in which case remove the
4061 -- now useless declaration.
4063 if Nkind (N) = N_Identifier
4064 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
4066 Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc));
4069 Rewrite (N, Expression (Fst));
4071 elsif Nkind (N) = N_Identifier
4072 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
4074 -- The block assigns the result of the call to the temporary
4076 Insert_After (Parent (Entity (N)), Blk);
4078 -- If the context is an assignment, and the left-hand side is free of
4079 -- side-effects, the replacement is also safe.
4080 -- Can this be generalized further???
4082 elsif Nkind (Parent (N)) = N_Assignment_Statement
4084 (Is_Entity_Name (Name (Parent (N)))
4086 (Nkind (Name (Parent (N))) = N_Explicit_Dereference
4087 and then Is_Entity_Name (Prefix (Name (Parent (N)))))
4090 (Nkind (Name (Parent (N))) = N_Selected_Component
4091 and then Is_Entity_Name (Prefix (Name (Parent (N))))))
4093 -- Replace assignment with the block
4096 Original_Assignment : constant Node_Id := Parent (N);
4099 -- Preserve the original assignment node to keep the complete
4100 -- assignment subtree consistent enough for Analyze_Assignment
4101 -- to proceed (specifically, the original Lhs node must still
4102 -- have an assignment statement as its parent).
4104 -- We cannot rely on Original_Node to go back from the block
4105 -- node to the assignment node, because the assignment might
4106 -- already be a rewrite substitution.
4108 Discard_Node (Relocate_Node (Original_Assignment));
4109 Rewrite (Original_Assignment, Blk);
4112 elsif Nkind (Parent (N)) = N_Object_Declaration then
4113 Set_Expression (Parent (N), Empty);
4114 Insert_After (Parent (N), Blk);
4117 Insert_Before (Parent (N), Blk);
4119 end Rewrite_Function_Call;
4121 ----------------------------
4122 -- Rewrite_Procedure_Call --
4123 ----------------------------
4125 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is
4126 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
4129 -- If there is a transient scope for N, this will be the scope of the
4130 -- actions for N, and the statements in Blk need to be within this
4131 -- scope. For example, they need to have visibility on the constant
4132 -- declarations created for the formals.
4134 -- If N needs no transient scope, and if there are no declarations in
4135 -- the inlined body, we can do a little optimization and insert the
4136 -- statements for the body directly after N, and rewrite N to a
4137 -- null statement, instead of rewriting N into a full-blown block
4140 if not Scope_Is_Transient
4141 and then Is_Empty_List (Declarations (Blk))
4143 Insert_List_After (N, Statements (HSS));
4144 Rewrite (N, Make_Null_Statement (Loc));
4148 end Rewrite_Procedure_Call;
4150 -------------------------
4151 -- Formal_Is_Used_Once --
4152 -------------------------
4154 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is
4155 Use_Counter : Int := 0;
4157 function Count_Uses (N : Node_Id) return Traverse_Result;
4158 -- Traverse the tree and count the uses of the formal parameter.
4159 -- In this case, for optimization purposes, we do not need to
4160 -- continue the traversal once more than one use is encountered.
4166 function Count_Uses (N : Node_Id) return Traverse_Result is
4168 -- The original node is an identifier
4170 if Nkind (N) = N_Identifier
4171 and then Present (Entity (N))
4173 -- Original node's entity points to the one in the copied body
4175 and then Nkind (Entity (N)) = N_Identifier
4176 and then Present (Entity (Entity (N)))
4178 -- The entity of the copied node is the formal parameter
4180 and then Entity (Entity (N)) = Formal
4182 Use_Counter := Use_Counter + 1;
4184 if Use_Counter > 1 then
4186 -- Denote more than one use and abandon the traversal
4197 procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses);
4199 -- Start of processing for Formal_Is_Used_Once
4202 Count_Formal_Uses (Orig_Bod);
4203 return Use_Counter = 1;
4204 end Formal_Is_Used_Once;
4206 -- Start of processing for Expand_Inlined_Call
4209 -- Check for an illegal attempt to inline a recursive procedure. If the
4210 -- subprogram has parameters this is detected when trying to supply a
4211 -- binding for parameters that already have one. For parameterless
4212 -- subprograms this must be done explicitly.
4214 if In_Open_Scopes (Subp) then
4215 Error_Msg_N ("call to recursive subprogram cannot be inlined?", N);
4216 Set_Is_Inlined (Subp, False);
4220 if Nkind (Orig_Bod) = N_Defining_Identifier
4221 or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol
4223 -- Subprogram is renaming_as_body. Calls occurring after the renaming
4224 -- can be replaced with calls to the renamed entity directly, because
4225 -- the subprograms are subtype conformant. If the renamed subprogram
4226 -- is an inherited operation, we must redo the expansion because
4227 -- implicit conversions may be needed. Similarly, if the renamed
4228 -- entity is inlined, expand the call for further optimizations.
4230 Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc));
4232 if Present (Alias (Orig_Bod)) or else Is_Inlined (Orig_Bod) then
4239 -- Use generic machinery to copy body of inlined subprogram, as if it
4240 -- were an instantiation, resetting source locations appropriately, so
4241 -- that nested inlined calls appear in the main unit.
4243 Save_Env (Subp, Empty);
4244 Set_Copied_Sloc_For_Inlined_Body (N, Defining_Entity (Orig_Bod));
4246 Bod := Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True);
4248 Make_Block_Statement (Loc,
4249 Declarations => Declarations (Bod),
4250 Handled_Statement_Sequence => Handled_Statement_Sequence (Bod));
4252 if No (Declarations (Bod)) then
4253 Set_Declarations (Blk, New_List);
4256 -- For the unconstrained case, capture the name of the local variable
4257 -- that holds the result. This must be the first declaration in the
4258 -- block, because its bounds cannot depend on local variables. Otherwise
4259 -- there is no way to declare the result outside of the block. Needless
4260 -- to say, in general the bounds will depend on the actuals in the call.
4262 -- If the context is an assignment statement, as is the case for the
4263 -- expansion of an extended return, the left-hand side provides bounds
4264 -- even if the return type is unconstrained.
4267 if Nkind (Parent (N)) /= N_Assignment_Statement then
4268 Targ1 := Defining_Identifier (First (Declarations (Blk)));
4270 Targ1 := Name (Parent (N));
4274 -- If this is a derived function, establish the proper return type
4276 if Present (Orig_Subp) and then Orig_Subp /= Subp then
4277 Ret_Type := Etype (Orig_Subp);
4279 Ret_Type := Etype (Subp);
4282 -- Create temporaries for the actuals that are expressions, or that
4283 -- are scalars and require copying to preserve semantics.
4285 F := First_Formal (Subp);
4286 A := First_Actual (N);
4287 while Present (F) loop
4288 if Present (Renamed_Object (F)) then
4289 Error_Msg_N ("cannot inline call to recursive subprogram", N);
4293 -- If the argument may be a controlling argument in a call within
4294 -- the inlined body, we must preserve its classwide nature to insure
4295 -- that dynamic dispatching take place subsequently. If the formal
4296 -- has a constraint it must be preserved to retain the semantics of
4299 if Is_Class_Wide_Type (Etype (F))
4300 or else (Is_Access_Type (Etype (F))
4301 and then Is_Class_Wide_Type (Designated_Type (Etype (F))))
4303 Temp_Typ := Etype (F);
4305 elsif Base_Type (Etype (F)) = Base_Type (Etype (A))
4306 and then Etype (F) /= Base_Type (Etype (F))
4308 Temp_Typ := Etype (F);
4310 Temp_Typ := Etype (A);
4313 -- If the actual is a simple name or a literal, no need to
4314 -- create a temporary, object can be used directly.
4316 -- If the actual is a literal and the formal has its address taken,
4317 -- we cannot pass the literal itself as an argument, so its value
4318 -- must be captured in a temporary.
4320 if (Is_Entity_Name (A)
4322 (not Is_Scalar_Type (Etype (A))
4323 or else Ekind (Entity (A)) = E_Enumeration_Literal))
4325 -- When the actual is an identifier and the corresponding formal
4326 -- is used only once in the original body, the formal can be
4327 -- substituted directly with the actual parameter.
4329 or else (Nkind (A) = N_Identifier
4330 and then Formal_Is_Used_Once (F))
4333 (Nkind_In (A, N_Real_Literal,
4335 N_Character_Literal)
4336 and then not Address_Taken (F))
4338 if Etype (F) /= Etype (A) then
4340 (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A)));
4342 Set_Renamed_Object (F, A);
4346 Temp := Make_Temporary (Loc, 'C');
4348 -- If the actual for an in/in-out parameter is a view conversion,
4349 -- make it into an unchecked conversion, given that an untagged
4350 -- type conversion is not a proper object for a renaming.
4352 -- In-out conversions that involve real conversions have already
4353 -- been transformed in Expand_Actuals.
4355 if Nkind (A) = N_Type_Conversion
4356 and then Ekind (F) /= E_In_Parameter
4359 Make_Unchecked_Type_Conversion (Loc,
4360 Subtype_Mark => New_Occurrence_Of (Etype (F), Loc),
4361 Expression => Relocate_Node (Expression (A)));
4363 elsif Etype (F) /= Etype (A) then
4364 New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A));
4365 Temp_Typ := Etype (F);
4368 New_A := Relocate_Node (A);
4371 Set_Sloc (New_A, Sloc (N));
4373 -- If the actual has a by-reference type, it cannot be copied, so
4374 -- its value is captured in a renaming declaration. Otherwise
4375 -- declare a local constant initialized with the actual.
4377 -- We also use a renaming declaration for expressions of an array
4378 -- type that is not bit-packed, both for efficiency reasons and to
4379 -- respect the semantics of the call: in most cases the original
4380 -- call will pass the parameter by reference, and thus the inlined
4381 -- code will have the same semantics.
4383 if Ekind (F) = E_In_Parameter
4384 and then not Is_By_Reference_Type (Etype (A))
4386 (not Is_Array_Type (Etype (A))
4387 or else not Is_Object_Reference (A)
4388 or else Is_Bit_Packed_Array (Etype (A)))
4391 Make_Object_Declaration (Loc,
4392 Defining_Identifier => Temp,
4393 Constant_Present => True,
4394 Object_Definition => New_Occurrence_Of (Temp_Typ, Loc),
4395 Expression => New_A);
4398 Make_Object_Renaming_Declaration (Loc,
4399 Defining_Identifier => Temp,
4400 Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc),
4404 Append (Decl, Decls);
4405 Set_Renamed_Object (F, Temp);
4412 -- Establish target of function call. If context is not assignment or
4413 -- declaration, create a temporary as a target. The declaration for the
4414 -- temporary may be subsequently optimized away if the body is a single
4415 -- expression, or if the left-hand side of the assignment is simple
4416 -- enough, i.e. an entity or an explicit dereference of one.
4418 if Ekind (Subp) = E_Function then
4419 if Nkind (Parent (N)) = N_Assignment_Statement
4420 and then Is_Entity_Name (Name (Parent (N)))
4422 Targ := Name (Parent (N));
4424 elsif Nkind (Parent (N)) = N_Assignment_Statement
4425 and then Nkind (Name (Parent (N))) = N_Explicit_Dereference
4426 and then Is_Entity_Name (Prefix (Name (Parent (N))))
4428 Targ := Name (Parent (N));
4430 elsif Nkind (Parent (N)) = N_Assignment_Statement
4431 and then Nkind (Name (Parent (N))) = N_Selected_Component
4432 and then Is_Entity_Name (Prefix (Name (Parent (N))))
4434 Targ := New_Copy_Tree (Name (Parent (N)));
4436 elsif Nkind (Parent (N)) = N_Object_Declaration
4437 and then Is_Limited_Type (Etype (Subp))
4439 Targ := Defining_Identifier (Parent (N));
4442 -- Replace call with temporary and create its declaration
4444 Temp := Make_Temporary (Loc, 'C');
4445 Set_Is_Internal (Temp);
4447 -- For the unconstrained case, the generated temporary has the
4448 -- same constrained declaration as the result variable. It may
4449 -- eventually be possible to remove that temporary and use the
4450 -- result variable directly.
4453 and then Nkind (Parent (N)) /= N_Assignment_Statement
4456 Make_Object_Declaration (Loc,
4457 Defining_Identifier => Temp,
4458 Object_Definition =>
4459 New_Copy_Tree (Object_Definition (Parent (Targ1))));
4461 Replace_Formals (Decl);
4465 Make_Object_Declaration (Loc,
4466 Defining_Identifier => Temp,
4467 Object_Definition => New_Occurrence_Of (Ret_Type, Loc));
4469 Set_Etype (Temp, Ret_Type);
4472 Set_No_Initialization (Decl);
4473 Append (Decl, Decls);
4474 Rewrite (N, New_Occurrence_Of (Temp, Loc));
4479 Insert_Actions (N, Decls);
4481 -- Traverse the tree and replace formals with actuals or their thunks.
4482 -- Attach block to tree before analysis and rewriting.
4484 Replace_Formals (Blk);
4485 Set_Parent (Blk, N);
4487 if not Comes_From_Source (Subp) or else Is_Predef then
4491 if Present (Exit_Lab) then
4493 -- If the body was a single expression, the single return statement
4494 -- and the corresponding label are useless.
4498 Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) =
4501 Remove (Last (Statements (Handled_Statement_Sequence (Blk))));
4503 Append (Lab_Decl, (Declarations (Blk)));
4504 Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk)));
4508 -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on
4509 -- conflicting private views that Gigi would ignore. If this is a
4510 -- predefined unit, analyze with checks off, as is done in the non-
4511 -- inlined run-time units.
4514 I_Flag : constant Boolean := In_Inlined_Body;
4517 In_Inlined_Body := True;
4521 Style : constant Boolean := Style_Check;
4523 Style_Check := False;
4524 Analyze (Blk, Suppress => All_Checks);
4525 Style_Check := Style;
4532 In_Inlined_Body := I_Flag;
4535 if Ekind (Subp) = E_Procedure then
4536 Rewrite_Procedure_Call (N, Blk);
4539 Rewrite_Function_Call (N, Blk);
4541 -- For the unconstrained case, the replacement of the call has been
4542 -- made prior to the complete analysis of the generated declarations.
4543 -- Propagate the proper type now.
4546 if Nkind (N) = N_Identifier then
4547 Set_Etype (N, Etype (Entity (N)));
4549 Set_Etype (N, Etype (Targ1));
4556 -- Cleanup mapping between formals and actuals for other expansions
4558 F := First_Formal (Subp);
4559 while Present (F) loop
4560 Set_Renamed_Object (F, Empty);
4563 end Expand_Inlined_Call;
4565 ----------------------------------------
4566 -- Expand_N_Extended_Return_Statement --
4567 ----------------------------------------
4569 -- If there is a Handled_Statement_Sequence, we rewrite this:
4571 -- return Result : T := <expression> do
4572 -- <handled_seq_of_stms>
4578 -- Result : T := <expression>;
4580 -- <handled_seq_of_stms>
4584 -- Otherwise (no Handled_Statement_Sequence), we rewrite this:
4586 -- return Result : T := <expression>;
4590 -- return <expression>;
4592 -- unless it's build-in-place or there's no <expression>, in which case
4596 -- Result : T := <expression>;
4601 -- Note that this case could have been written by the user as an extended
4602 -- return statement, or could have been transformed to this from a simple
4603 -- return statement.
4605 -- That is, we need to have a reified return object if there are statements
4606 -- (which might refer to it) or if we're doing build-in-place (so we can
4607 -- set its address to the final resting place or if there is no expression
4608 -- (in which case default initial values might need to be set).
4610 procedure Expand_N_Extended_Return_Statement (N : Node_Id) is
4611 Loc : constant Source_Ptr := Sloc (N);
4613 Par_Func : constant Entity_Id :=
4614 Return_Applies_To (Return_Statement_Entity (N));
4615 Result_Subt : constant Entity_Id := Etype (Par_Func);
4616 Ret_Obj_Id : constant Entity_Id :=
4617 First_Entity (Return_Statement_Entity (N));
4618 Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id);
4620 Is_Build_In_Place : constant Boolean :=
4621 Is_Build_In_Place_Function (Par_Func);
4626 Return_Stmt : Node_Id;
4629 function Build_Heap_Allocator
4630 (Temp_Id : Entity_Id;
4631 Temp_Typ : Entity_Id;
4632 Func_Id : Entity_Id;
4633 Ret_Typ : Entity_Id;
4634 Alloc_Expr : Node_Id) return Node_Id;
4635 -- Create the statements necessary to allocate a return object on the
4636 -- caller's master. The master is available through implicit parameter
4637 -- BIPfinalizationmaster.
4639 -- if BIPfinalizationmaster /= null then
4641 -- type Ptr_Typ is access Ret_Typ;
4642 -- for Ptr_Typ'Storage_Pool use
4643 -- Base_Pool (BIPfinalizationmaster.all).all;
4647 -- procedure Allocate (...) is
4649 -- System.Storage_Pools.Subpools.Allocate_Any (...);
4652 -- Local := <Alloc_Expr>;
4653 -- Temp_Id := Temp_Typ (Local);
4657 -- Temp_Id is the temporary which is used to reference the internally
4658 -- created object in all allocation forms. Temp_Typ is the type of the
4659 -- temporary. Func_Id is the enclosing function. Ret_Typ is the return
4660 -- type of Func_Id. Alloc_Expr is the actual allocator.
4662 function Move_Activation_Chain return Node_Id;
4663 -- Construct a call to System.Tasking.Stages.Move_Activation_Chain
4665 -- From current activation chain
4666 -- To activation chain passed in by the caller
4667 -- New_Master master passed in by the caller
4669 --------------------------
4670 -- Build_Heap_Allocator --
4671 --------------------------
4673 function Build_Heap_Allocator
4674 (Temp_Id : Entity_Id;
4675 Temp_Typ : Entity_Id;
4676 Func_Id : Entity_Id;
4677 Ret_Typ : Entity_Id;
4678 Alloc_Expr : Node_Id) return Node_Id
4681 pragma Assert (Is_Build_In_Place_Function (Func_Id));
4683 -- Processing for build-in-place object allocation. This is disabled
4684 -- on .NET/JVM because the targets do not support pools.
4686 if VM_Target = No_VM
4687 and then Needs_Finalization (Ret_Typ)
4690 Decls : constant List_Id := New_List;
4691 Fin_Mas_Id : constant Entity_Id :=
4692 Build_In_Place_Formal
4693 (Func_Id, BIP_Finalization_Master);
4694 Stmts : constant List_Id := New_List;
4695 Desig_Typ : Entity_Id;
4696 Local_Id : Entity_Id;
4697 Pool_Id : Entity_Id;
4698 Ptr_Typ : Entity_Id;
4702 -- Pool_Id renames Base_Pool (BIPfinalizationmaster.all).all;
4704 Pool_Id := Make_Temporary (Loc, 'P');
4707 Make_Object_Renaming_Declaration (Loc,
4708 Defining_Identifier => Pool_Id,
4710 New_Reference_To (RTE (RE_Root_Storage_Pool), Loc),
4712 Make_Explicit_Dereference (Loc,
4714 Make_Function_Call (Loc,
4716 New_Reference_To (RTE (RE_Base_Pool), Loc),
4717 Parameter_Associations => New_List (
4718 Make_Explicit_Dereference (Loc,
4720 New_Reference_To (Fin_Mas_Id, Loc)))))));
4722 -- Create an access type which uses the storage pool of the
4723 -- caller's master. This additional type is necessary because
4724 -- the finalization master cannot be associated with the type
4725 -- of the temporary. Otherwise the secondary stack allocation
4728 Desig_Typ := Ret_Typ;
4730 -- Ensure that the build-in-place machinery uses a fat pointer
4731 -- when allocating an unconstrained array on the heap. In this
4732 -- case the result object type is a constrained array type even
4733 -- though the function type is unconstrained.
4735 if Ekind (Desig_Typ) = E_Array_Subtype then
4736 Desig_Typ := Base_Type (Desig_Typ);
4740 -- type Ptr_Typ is access Desig_Typ;
4742 Ptr_Typ := Make_Temporary (Loc, 'P');
4745 Make_Full_Type_Declaration (Loc,
4746 Defining_Identifier => Ptr_Typ,
4748 Make_Access_To_Object_Definition (Loc,
4749 Subtype_Indication =>
4750 New_Reference_To (Desig_Typ, Loc))));
4752 -- Perform minor decoration in order to set the master and the
4753 -- storage pool attributes.
4755 Set_Ekind (Ptr_Typ, E_Access_Type);
4756 Set_Finalization_Master (Ptr_Typ, Fin_Mas_Id);
4757 Set_Associated_Storage_Pool (Ptr_Typ, Pool_Id);
4759 -- Create the temporary, generate:
4760 -- Local_Id : Ptr_Typ;
4762 Local_Id := Make_Temporary (Loc, 'T');
4765 Make_Object_Declaration (Loc,
4766 Defining_Identifier => Local_Id,
4767 Object_Definition =>
4768 New_Reference_To (Ptr_Typ, Loc)));
4770 -- Allocate the object, generate:
4771 -- Local_Id := <Alloc_Expr>;
4774 Make_Assignment_Statement (Loc,
4775 Name => New_Reference_To (Local_Id, Loc),
4776 Expression => Alloc_Expr));
4779 -- Temp_Id := Temp_Typ (Local_Id);
4782 Make_Assignment_Statement (Loc,
4783 Name => New_Reference_To (Temp_Id, Loc),
4785 Unchecked_Convert_To (Temp_Typ,
4786 New_Reference_To (Local_Id, Loc))));
4788 -- Wrap the allocation in a block. This is further conditioned
4789 -- by checking the caller finalization master at runtime. A
4790 -- null value indicates a non-existent master, most likely due
4791 -- to a Finalize_Storage_Only allocation.
4794 -- if BIPfinalizationmaster /= null then
4803 Make_If_Statement (Loc,
4806 Left_Opnd => New_Reference_To (Fin_Mas_Id, Loc),
4807 Right_Opnd => Make_Null (Loc)),
4809 Then_Statements => New_List (
4810 Make_Block_Statement (Loc,
4811 Declarations => Decls,
4812 Handled_Statement_Sequence =>
4813 Make_Handled_Sequence_Of_Statements (Loc,
4814 Statements => Stmts))));
4817 -- For all other cases, generate:
4818 -- Temp_Id := <Alloc_Expr>;
4822 Make_Assignment_Statement (Loc,
4823 Name => New_Reference_To (Temp_Id, Loc),
4824 Expression => Alloc_Expr);
4826 end Build_Heap_Allocator;
4828 ---------------------------
4829 -- Move_Activation_Chain --
4830 ---------------------------
4832 function Move_Activation_Chain return Node_Id is
4835 Make_Procedure_Call_Statement (Loc,
4837 New_Reference_To (RTE (RE_Move_Activation_Chain), Loc),
4839 Parameter_Associations => New_List (
4843 Make_Attribute_Reference (Loc,
4844 Prefix => Make_Identifier (Loc, Name_uChain),
4845 Attribute_Name => Name_Unrestricted_Access),
4847 -- Destination chain
4850 (Build_In_Place_Formal (Par_Func, BIP_Activation_Chain), Loc),
4855 (Build_In_Place_Formal (Par_Func, BIP_Task_Master), Loc)));
4856 end Move_Activation_Chain;
4858 -- Start of processing for Expand_N_Extended_Return_Statement
4861 if Nkind (Ret_Obj_Decl) = N_Object_Declaration then
4862 Exp := Expression (Ret_Obj_Decl);
4867 HSS := Handled_Statement_Sequence (N);
4869 -- If the returned object needs finalization actions, the function must
4870 -- perform the appropriate cleanup should it fail to return. The state
4871 -- of the function itself is tracked through a flag which is coupled
4872 -- with the scope finalizer. There is one flag per each return object
4873 -- in case of multiple returns.
4875 if Is_Build_In_Place
4876 and then Needs_Finalization (Etype (Ret_Obj_Id))
4879 Flag_Decl : Node_Id;
4880 Flag_Id : Entity_Id;
4884 -- Recover the function body
4886 Func_Bod := Unit_Declaration_Node (Par_Func);
4888 if Nkind (Func_Bod) = N_Subprogram_Declaration then
4889 Func_Bod := Parent (Parent (Corresponding_Body (Func_Bod)));
4892 -- Create a flag to track the function state
4894 Flag_Id := Make_Temporary (Loc, 'F');
4895 Set_Return_Flag_Or_Transient_Decl (Ret_Obj_Id, Flag_Id);
4897 -- Insert the flag at the beginning of the function declarations,
4899 -- Fnn : Boolean := False;
4902 Make_Object_Declaration (Loc,
4903 Defining_Identifier => Flag_Id,
4904 Object_Definition =>
4905 New_Reference_To (Standard_Boolean, Loc),
4906 Expression => New_Reference_To (Standard_False, Loc));
4908 Prepend_To (Declarations (Func_Bod), Flag_Decl);
4909 Analyze (Flag_Decl);
4913 -- Build a simple_return_statement that returns the return object when
4914 -- there is a statement sequence, or no expression, or the result will
4915 -- be built in place. Note however that we currently do this for all
4916 -- composite cases, even though nonlimited composite results are not yet
4917 -- built in place (though we plan to do so eventually).
4920 or else Is_Composite_Type (Result_Subt)
4926 -- If the extended return has a handled statement sequence, then wrap
4927 -- it in a block and use the block as the first statement.
4931 Make_Block_Statement (Loc,
4932 Declarations => New_List,
4933 Handled_Statement_Sequence => HSS));
4936 -- If the result type contains tasks, we call Move_Activation_Chain.
4937 -- Later, the cleanup code will call Complete_Master, which will
4938 -- terminate any unactivated tasks belonging to the return statement
4939 -- master. But Move_Activation_Chain updates their master to be that
4940 -- of the caller, so they will not be terminated unless the return
4941 -- statement completes unsuccessfully due to exception, abort, goto,
4942 -- or exit. As a formality, we test whether the function requires the
4943 -- result to be built in place, though that's necessarily true for
4944 -- the case of result types with task parts.
4946 if Is_Build_In_Place
4947 and then Has_Task (Result_Subt)
4949 -- The return expression is an aggregate for a complex type which
4950 -- contains tasks. This particular case is left unexpanded since
4951 -- the regular expansion would insert all temporaries and
4952 -- initialization code in the wrong block.
4954 if Nkind (Exp) = N_Aggregate then
4955 Expand_N_Aggregate (Exp);
4958 -- Do not move the activation chain if the return object does not
4961 if Has_Task (Etype (Ret_Obj_Id)) then
4962 Append_To (Stmts, Move_Activation_Chain);
4966 -- Update the state of the function right before the object is
4969 if Is_Build_In_Place
4970 and then Needs_Finalization (Etype (Ret_Obj_Id))
4973 Flag_Id : constant Entity_Id :=
4974 Return_Flag_Or_Transient_Decl (Ret_Obj_Id);
4981 Make_Assignment_Statement (Loc,
4982 Name => New_Reference_To (Flag_Id, Loc),
4983 Expression => New_Reference_To (Standard_True, Loc)));
4987 -- Build a simple_return_statement that returns the return object
4990 Make_Simple_Return_Statement (Loc,
4991 Expression => New_Occurrence_Of (Ret_Obj_Id, Loc));
4992 Append_To (Stmts, Return_Stmt);
4994 HSS := Make_Handled_Sequence_Of_Statements (Loc, Stmts);
4997 -- Case where we build a return statement block
4999 if Present (HSS) then
5001 Make_Block_Statement (Loc,
5002 Declarations => Return_Object_Declarations (N),
5003 Handled_Statement_Sequence => HSS);
5005 -- We set the entity of the new block statement to be that of the
5006 -- return statement. This is necessary so that various fields, such
5007 -- as Finalization_Chain_Entity carry over from the return statement
5008 -- to the block. Note that this block is unusual, in that its entity
5009 -- is an E_Return_Statement rather than an E_Block.
5012 (Result, New_Occurrence_Of (Return_Statement_Entity (N), Loc));
5014 -- If the object decl was already rewritten as a renaming, then we
5015 -- don't want to do the object allocation and transformation of of
5016 -- the return object declaration to a renaming. This case occurs
5017 -- when the return object is initialized by a call to another
5018 -- build-in-place function, and that function is responsible for
5019 -- the allocation of the return object.
5021 if Is_Build_In_Place
5022 and then Nkind (Ret_Obj_Decl) = N_Object_Renaming_Declaration
5025 (Nkind (Original_Node (Ret_Obj_Decl)) = N_Object_Declaration
5026 and then Is_Build_In_Place_Function_Call
5027 (Expression (Original_Node (Ret_Obj_Decl))));
5029 -- Return the build-in-place result by reference
5031 Set_By_Ref (Return_Stmt);
5033 elsif Is_Build_In_Place then
5035 -- Locate the implicit access parameter associated with the
5036 -- caller-supplied return object and convert the return
5037 -- statement's return object declaration to a renaming of a
5038 -- dereference of the access parameter. If the return object's
5039 -- declaration includes an expression that has not already been
5040 -- expanded as separate assignments, then add an assignment
5041 -- statement to ensure the return object gets initialized.
5044 -- Result : T [:= <expression>];
5051 -- Result : T renames FuncRA.all;
5052 -- [Result := <expression;]
5057 Return_Obj_Id : constant Entity_Id :=
5058 Defining_Identifier (Ret_Obj_Decl);
5059 Return_Obj_Typ : constant Entity_Id := Etype (Return_Obj_Id);
5060 Return_Obj_Expr : constant Node_Id :=
5061 Expression (Ret_Obj_Decl);
5062 Constr_Result : constant Boolean :=
5063 Is_Constrained (Result_Subt);
5064 Obj_Alloc_Formal : Entity_Id;
5065 Object_Access : Entity_Id;
5066 Obj_Acc_Deref : Node_Id;
5067 Init_Assignment : Node_Id := Empty;
5070 -- Build-in-place results must be returned by reference
5072 Set_By_Ref (Return_Stmt);
5074 -- Retrieve the implicit access parameter passed by the caller
5077 Build_In_Place_Formal (Par_Func, BIP_Object_Access);
5079 -- If the return object's declaration includes an expression
5080 -- and the declaration isn't marked as No_Initialization, then
5081 -- we need to generate an assignment to the object and insert
5082 -- it after the declaration before rewriting it as a renaming
5083 -- (otherwise we'll lose the initialization). The case where
5084 -- the result type is an interface (or class-wide interface)
5085 -- is also excluded because the context of the function call
5086 -- must be unconstrained, so the initialization will always
5087 -- be done as part of an allocator evaluation (storage pool
5088 -- or secondary stack), never to a constrained target object
5089 -- passed in by the caller. Besides the assignment being
5090 -- unneeded in this case, it avoids problems with trying to
5091 -- generate a dispatching assignment when the return expression
5092 -- is a nonlimited descendant of a limited interface (the
5093 -- interface has no assignment operation).
5095 if Present (Return_Obj_Expr)
5096 and then not No_Initialization (Ret_Obj_Decl)
5097 and then not Is_Interface (Return_Obj_Typ)
5100 Make_Assignment_Statement (Loc,
5101 Name => New_Reference_To (Return_Obj_Id, Loc),
5102 Expression => Relocate_Node (Return_Obj_Expr));
5104 Set_Etype (Name (Init_Assignment), Etype (Return_Obj_Id));
5105 Set_Assignment_OK (Name (Init_Assignment));
5106 Set_No_Ctrl_Actions (Init_Assignment);
5108 Set_Parent (Name (Init_Assignment), Init_Assignment);
5109 Set_Parent (Expression (Init_Assignment), Init_Assignment);
5111 Set_Expression (Ret_Obj_Decl, Empty);
5113 if Is_Class_Wide_Type (Etype (Return_Obj_Id))
5114 and then not Is_Class_Wide_Type
5115 (Etype (Expression (Init_Assignment)))
5117 Rewrite (Expression (Init_Assignment),
5118 Make_Type_Conversion (Loc,
5120 New_Occurrence_Of (Etype (Return_Obj_Id), Loc),
5122 Relocate_Node (Expression (Init_Assignment))));
5125 -- In the case of functions where the calling context can
5126 -- determine the form of allocation needed, initialization
5127 -- is done with each part of the if statement that handles
5128 -- the different forms of allocation (this is true for
5129 -- unconstrained and tagged result subtypes).
5132 and then not Is_Tagged_Type (Underlying_Type (Result_Subt))
5134 Insert_After (Ret_Obj_Decl, Init_Assignment);
5138 -- When the function's subtype is unconstrained, a run-time
5139 -- test is needed to determine the form of allocation to use
5140 -- for the return object. The function has an implicit formal
5141 -- parameter indicating this. If the BIP_Alloc_Form formal has
5142 -- the value one, then the caller has passed access to an
5143 -- existing object for use as the return object. If the value
5144 -- is two, then the return object must be allocated on the
5145 -- secondary stack. Otherwise, the object must be allocated in
5146 -- a storage pool (currently only supported for the global
5147 -- heap, user-defined storage pools TBD ???). We generate an
5148 -- if statement to test the implicit allocation formal and
5149 -- initialize a local access value appropriately, creating
5150 -- allocators in the secondary stack and global heap cases.
5151 -- The special formal also exists and must be tested when the
5152 -- function has a tagged result, even when the result subtype
5153 -- is constrained, because in general such functions can be
5154 -- called in dispatching contexts and must be handled similarly
5155 -- to functions with a class-wide result.
5157 if not Constr_Result
5158 or else Is_Tagged_Type (Underlying_Type (Result_Subt))
5161 Build_In_Place_Formal (Par_Func, BIP_Alloc_Form);
5164 Pool_Id : constant Entity_Id :=
5165 Make_Temporary (Loc, 'P');
5166 Alloc_Obj_Id : Entity_Id;
5167 Alloc_Obj_Decl : Node_Id;
5168 Alloc_If_Stmt : Node_Id;
5169 Heap_Allocator : Node_Id;
5170 Pool_Decl : Node_Id;
5171 Pool_Allocator : Node_Id;
5172 Ptr_Type_Decl : Node_Id;
5173 Ref_Type : Entity_Id;
5174 SS_Allocator : Node_Id;
5177 -- Reuse the itype created for the function's implicit
5178 -- access formal. This avoids the need to create a new
5179 -- access type here, plus it allows assigning the access
5180 -- formal directly without applying a conversion.
5182 -- Ref_Type := Etype (Object_Access);
5184 -- Create an access type designating the function's
5187 Ref_Type := Make_Temporary (Loc, 'A');
5190 Make_Full_Type_Declaration (Loc,
5191 Defining_Identifier => Ref_Type,
5193 Make_Access_To_Object_Definition (Loc,
5194 All_Present => True,
5195 Subtype_Indication =>
5196 New_Reference_To (Return_Obj_Typ, Loc)));
5198 Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl);
5200 -- Create an access object that will be initialized to an
5201 -- access value denoting the return object, either coming
5202 -- from an implicit access value passed in by the caller
5203 -- or from the result of an allocator.
5205 Alloc_Obj_Id := Make_Temporary (Loc, 'R');
5206 Set_Etype (Alloc_Obj_Id, Ref_Type);
5209 Make_Object_Declaration (Loc,
5210 Defining_Identifier => Alloc_Obj_Id,
5211 Object_Definition =>
5212 New_Reference_To (Ref_Type, Loc));
5214 Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl);
5216 -- Create allocators for both the secondary stack and
5217 -- global heap. If there's an initialization expression,
5218 -- then create these as initialized allocators.
5220 if Present (Return_Obj_Expr)
5221 and then not No_Initialization (Ret_Obj_Decl)
5223 -- Always use the type of the expression for the
5224 -- qualified expression, rather than the result type.
5225 -- In general we cannot always use the result type
5226 -- for the allocator, because the expression might be
5227 -- of a specific type, such as in the case of an
5228 -- aggregate or even a nonlimited object when the
5229 -- result type is a limited class-wide interface type.
5232 Make_Allocator (Loc,
5234 Make_Qualified_Expression (Loc,
5237 (Etype (Return_Obj_Expr), Loc),
5239 New_Copy_Tree (Return_Obj_Expr)));
5242 -- If the function returns a class-wide type we cannot
5243 -- use the return type for the allocator. Instead we
5244 -- use the type of the expression, which must be an
5245 -- aggregate of a definite type.
5247 if Is_Class_Wide_Type (Return_Obj_Typ) then
5249 Make_Allocator (Loc,
5252 (Etype (Return_Obj_Expr), Loc));
5255 Make_Allocator (Loc,
5257 New_Reference_To (Return_Obj_Typ, Loc));
5260 -- If the object requires default initialization then
5261 -- that will happen later following the elaboration of
5262 -- the object renaming. If we don't turn it off here
5263 -- then the object will be default initialized twice.
5265 Set_No_Initialization (Heap_Allocator);
5268 -- The Pool_Allocator is just like the Heap_Allocator,
5269 -- except we set Storage_Pool and Procedure_To_Call so
5270 -- it will use the user-defined storage pool.
5272 Pool_Allocator := New_Copy_Tree (Heap_Allocator);
5274 -- Do not generate the renaming of the build-in-place
5275 -- pool parameter on .NET/JVM/ZFP because the parameter
5276 -- is not created in the first place.
5278 if VM_Target = No_VM
5279 and then RTE_Available (RE_Root_Storage_Pool_Ptr)
5282 Make_Object_Renaming_Declaration (Loc,
5283 Defining_Identifier => Pool_Id,
5286 (RTE (RE_Root_Storage_Pool), Loc),
5288 Make_Explicit_Dereference (Loc,
5290 (Build_In_Place_Formal
5291 (Par_Func, BIP_Storage_Pool), Loc)));
5292 Set_Storage_Pool (Pool_Allocator, Pool_Id);
5293 Set_Procedure_To_Call
5294 (Pool_Allocator, RTE (RE_Allocate_Any));
5296 Pool_Decl := Make_Null_Statement (Loc);
5299 -- If the No_Allocators restriction is active, then only
5300 -- an allocator for secondary stack allocation is needed.
5301 -- It's OK for such allocators to have Comes_From_Source
5302 -- set to False, because gigi knows not to flag them as
5303 -- being a violation of No_Implicit_Heap_Allocations.
5305 if Restriction_Active (No_Allocators) then
5306 SS_Allocator := Heap_Allocator;
5307 Heap_Allocator := Make_Null (Loc);
5308 Pool_Allocator := Make_Null (Loc);
5310 -- Otherwise the heap and pool allocators may be needed,
5311 -- so we make another allocator for secondary stack
5315 SS_Allocator := New_Copy_Tree (Heap_Allocator);
5317 -- The heap and pool allocators are marked as
5318 -- Comes_From_Source since they correspond to an
5319 -- explicit user-written allocator (that is, it will
5320 -- only be executed on behalf of callers that call the
5321 -- function as initialization for such an allocator).
5322 -- Prevents errors when No_Implicit_Heap_Allocations
5325 Set_Comes_From_Source (Heap_Allocator, True);
5326 Set_Comes_From_Source (Pool_Allocator, True);
5329 -- The allocator is returned on the secondary stack. We
5330 -- don't do this on VM targets, since the SS is not used.
5332 if VM_Target = No_VM then
5333 Set_Storage_Pool (SS_Allocator, RTE (RE_SS_Pool));
5334 Set_Procedure_To_Call
5335 (SS_Allocator, RTE (RE_SS_Allocate));
5337 -- The allocator is returned on the secondary stack,
5338 -- so indicate that the function return, as well as
5339 -- the block that encloses the allocator, must not
5340 -- release it. The flags must be set now because
5341 -- the decision to use the secondary stack is done
5342 -- very late in the course of expanding the return
5343 -- statement, past the point where these flags are
5346 Set_Sec_Stack_Needed_For_Return (Par_Func);
5347 Set_Sec_Stack_Needed_For_Return
5348 (Return_Statement_Entity (N));
5349 Set_Uses_Sec_Stack (Par_Func);
5350 Set_Uses_Sec_Stack (Return_Statement_Entity (N));
5353 -- Create an if statement to test the BIP_Alloc_Form
5354 -- formal and initialize the access object to either the
5355 -- BIP_Object_Access formal (BIP_Alloc_Form =
5356 -- Caller_Allocation), the result of allocating the
5357 -- object in the secondary stack (BIP_Alloc_Form =
5358 -- Secondary_Stack), or else an allocator to create the
5359 -- return object in the heap or user-defined pool
5360 -- (BIP_Alloc_Form = Global_Heap or User_Storage_Pool).
5362 -- ??? An unchecked type conversion must be made in the
5363 -- case of assigning the access object formal to the
5364 -- local access object, because a normal conversion would
5365 -- be illegal in some cases (such as converting access-
5366 -- to-unconstrained to access-to-constrained), but the
5367 -- the unchecked conversion will presumably fail to work
5368 -- right in just such cases. It's not clear at all how to
5372 Make_If_Statement (Loc,
5376 New_Reference_To (Obj_Alloc_Formal, Loc),
5378 Make_Integer_Literal (Loc,
5379 UI_From_Int (BIP_Allocation_Form'Pos
5380 (Caller_Allocation)))),
5382 Then_Statements => New_List (
5383 Make_Assignment_Statement (Loc,
5385 New_Reference_To (Alloc_Obj_Id, Loc),
5387 Make_Unchecked_Type_Conversion (Loc,
5389 New_Reference_To (Ref_Type, Loc),
5391 New_Reference_To (Object_Access, Loc)))),
5393 Elsif_Parts => New_List (
5394 Make_Elsif_Part (Loc,
5398 New_Reference_To (Obj_Alloc_Formal, Loc),
5400 Make_Integer_Literal (Loc,
5401 UI_From_Int (BIP_Allocation_Form'Pos
5402 (Secondary_Stack)))),
5404 Then_Statements => New_List (
5405 Make_Assignment_Statement (Loc,
5407 New_Reference_To (Alloc_Obj_Id, Loc),
5408 Expression => SS_Allocator))),
5410 Make_Elsif_Part (Loc,
5414 New_Reference_To (Obj_Alloc_Formal, Loc),
5416 Make_Integer_Literal (Loc,
5417 UI_From_Int (BIP_Allocation_Form'Pos
5420 Then_Statements => New_List (
5421 Build_Heap_Allocator
5422 (Temp_Id => Alloc_Obj_Id,
5423 Temp_Typ => Ref_Type,
5424 Func_Id => Par_Func,
5425 Ret_Typ => Return_Obj_Typ,
5426 Alloc_Expr => Heap_Allocator)))),
5428 Else_Statements => New_List (
5430 Build_Heap_Allocator
5431 (Temp_Id => Alloc_Obj_Id,
5432 Temp_Typ => Ref_Type,
5433 Func_Id => Par_Func,
5434 Ret_Typ => Return_Obj_Typ,
5435 Alloc_Expr => Pool_Allocator)));
5437 -- If a separate initialization assignment was created
5438 -- earlier, append that following the assignment of the
5439 -- implicit access formal to the access object, to ensure
5440 -- that the return object is initialized in that case. In
5441 -- this situation, the target of the assignment must be
5442 -- rewritten to denote a dereference of the access to the
5443 -- return object passed in by the caller.
5445 if Present (Init_Assignment) then
5446 Rewrite (Name (Init_Assignment),
5447 Make_Explicit_Dereference (Loc,
5448 Prefix => New_Reference_To (Alloc_Obj_Id, Loc)));
5451 (Name (Init_Assignment), Etype (Return_Obj_Id));
5454 (Then_Statements (Alloc_If_Stmt), Init_Assignment);
5457 Insert_Before (Ret_Obj_Decl, Alloc_If_Stmt);
5459 -- Remember the local access object for use in the
5460 -- dereference of the renaming created below.
5462 Object_Access := Alloc_Obj_Id;
5466 -- Replace the return object declaration with a renaming of a
5467 -- dereference of the access value designating the return
5471 Make_Explicit_Dereference (Loc,
5472 Prefix => New_Reference_To (Object_Access, Loc));
5474 Rewrite (Ret_Obj_Decl,
5475 Make_Object_Renaming_Declaration (Loc,
5476 Defining_Identifier => Return_Obj_Id,
5477 Access_Definition => Empty,
5479 New_Occurrence_Of (Return_Obj_Typ, Loc),
5480 Name => Obj_Acc_Deref));
5482 Set_Renamed_Object (Return_Obj_Id, Obj_Acc_Deref);
5486 -- Case where we do not build a block
5489 -- We're about to drop Return_Object_Declarations on the floor, so
5490 -- we need to insert it, in case it got expanded into useful code.
5491 -- Remove side effects from expression, which may be duplicated in
5492 -- subsequent checks (see Expand_Simple_Function_Return).
5494 Insert_List_Before (N, Return_Object_Declarations (N));
5495 Remove_Side_Effects (Exp);
5497 -- Build simple_return_statement that returns the expression directly
5499 Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => Exp);
5500 Result := Return_Stmt;
5503 -- Set the flag to prevent infinite recursion
5505 Set_Comes_From_Extended_Return_Statement (Return_Stmt);
5507 Rewrite (N, Result);
5509 end Expand_N_Extended_Return_Statement;
5511 ----------------------------
5512 -- Expand_N_Function_Call --
5513 ----------------------------
5515 procedure Expand_N_Function_Call (N : Node_Id) is
5519 -- If the return value of a foreign compiled function is VAX Float, then
5520 -- expand the return (adjusts the location of the return value on
5521 -- Alpha/VMS, no-op everywhere else).
5522 -- Comes_From_Source intercepts recursive expansion.
5524 if Vax_Float (Etype (N))
5525 and then Nkind (N) = N_Function_Call
5526 and then Present (Name (N))
5527 and then Present (Entity (Name (N)))
5528 and then Has_Foreign_Convention (Entity (Name (N)))
5529 and then Comes_From_Source (Parent (N))
5531 Expand_Vax_Foreign_Return (N);
5533 end Expand_N_Function_Call;
5535 ---------------------------------------
5536 -- Expand_N_Procedure_Call_Statement --
5537 ---------------------------------------
5539 procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is
5542 end Expand_N_Procedure_Call_Statement;
5544 --------------------------------------
5545 -- Expand_N_Simple_Return_Statement --
5546 --------------------------------------
5548 procedure Expand_N_Simple_Return_Statement (N : Node_Id) is
5550 -- Defend against previous errors (i.e. the return statement calls a
5551 -- function that is not available in configurable runtime).
5553 if Present (Expression (N))
5554 and then Nkind (Expression (N)) = N_Empty
5559 -- Distinguish the function and non-function cases:
5561 case Ekind (Return_Applies_To (Return_Statement_Entity (N))) is
5564 E_Generic_Function =>
5565 Expand_Simple_Function_Return (N);
5568 E_Generic_Procedure |
5571 E_Return_Statement =>
5572 Expand_Non_Function_Return (N);
5575 raise Program_Error;
5579 when RE_Not_Available =>
5581 end Expand_N_Simple_Return_Statement;
5583 ------------------------------
5584 -- Expand_N_Subprogram_Body --
5585 ------------------------------
5587 -- Add poll call if ATC polling is enabled, unless the body will be inlined
5590 -- Add dummy push/pop label nodes at start and end to clear any local
5591 -- exception indications if local-exception-to-goto optimization is active.
5593 -- Add return statement if last statement in body is not a return statement
5594 -- (this makes things easier on Gigi which does not want to have to handle
5595 -- a missing return).
5597 -- Add call to Activate_Tasks if body is a task activator
5599 -- Deal with possible detection of infinite recursion
5601 -- Eliminate body completely if convention stubbed
5603 -- Encode entity names within body, since we will not need to reference
5604 -- these entities any longer in the front end.
5606 -- Initialize scalar out parameters if Initialize/Normalize_Scalars
5608 -- Reset Pure indication if any parameter has root type System.Address
5609 -- or has any parameters of limited types, where limited means that the
5610 -- run-time view is limited (i.e. the full type is limited).
5614 procedure Expand_N_Subprogram_Body (N : Node_Id) is
5615 Loc : constant Source_Ptr := Sloc (N);
5616 H : constant Node_Id := Handled_Statement_Sequence (N);
5617 Body_Id : Entity_Id;
5620 Spec_Id : Entity_Id;
5622 procedure Add_Return (S : List_Id);
5623 -- Append a return statement to the statement sequence S if the last
5624 -- statement is not already a return or a goto statement. Note that
5625 -- the latter test is not critical, it does not matter if we add a few
5626 -- extra returns, since they get eliminated anyway later on.
5632 procedure Add_Return (S : List_Id) is
5637 -- Get last statement, ignoring any Pop_xxx_Label nodes, which are
5638 -- not relevant in this context since they are not executable.
5640 Last_Stm := Last (S);
5641 while Nkind (Last_Stm) in N_Pop_xxx_Label loop
5645 -- Now insert return unless last statement is a transfer
5647 if not Is_Transfer (Last_Stm) then
5649 -- The source location for the return is the end label of the
5650 -- procedure if present. Otherwise use the sloc of the last
5651 -- statement in the list. If the list comes from a generated
5652 -- exception handler and we are not debugging generated code,
5653 -- all the statements within the handler are made invisible
5656 if Nkind (Parent (S)) = N_Exception_Handler
5657 and then not Comes_From_Source (Parent (S))
5659 Loc := Sloc (Last_Stm);
5660 elsif Present (End_Label (H)) then
5661 Loc := Sloc (End_Label (H));
5663 Loc := Sloc (Last_Stm);
5667 Rtn : constant Node_Id := Make_Simple_Return_Statement (Loc);
5670 -- Append return statement, and set analyzed manually. We can't
5671 -- call Analyze on this return since the scope is wrong.
5673 -- Note: it almost works to push the scope and then do the
5674 -- Analyze call, but something goes wrong in some weird cases
5675 -- and it is not worth worrying about ???
5680 -- Call _Postconditions procedure if appropriate. We need to
5681 -- do this explicitly because we did not analyze the generated
5682 -- return statement above, so the call did not get inserted.
5684 if Ekind (Spec_Id) = E_Procedure
5685 and then Has_Postconditions (Spec_Id)
5687 pragma Assert (Present (Postcondition_Proc (Spec_Id)));
5689 Make_Procedure_Call_Statement (Loc,
5691 New_Reference_To (Postcondition_Proc (Spec_Id), Loc)));
5697 -- Start of processing for Expand_N_Subprogram_Body
5700 -- Set L to either the list of declarations if present, or to the list
5701 -- of statements if no declarations are present. This is used to insert
5702 -- new stuff at the start.
5704 if Is_Non_Empty_List (Declarations (N)) then
5705 L := Declarations (N);
5707 L := Statements (H);
5710 -- If local-exception-to-goto optimization active, insert dummy push
5711 -- statements at start, and dummy pop statements at end, but inhibit
5712 -- this if we have No_Exception_Handlers, since they are useless and
5713 -- intefere with analysis, e.g. by codepeer.
5715 if (Debug_Flag_Dot_G
5716 or else Restriction_Active (No_Exception_Propagation))
5717 and then not Restriction_Active (No_Exception_Handlers)
5718 and then not CodePeer_Mode
5719 and then Is_Non_Empty_List (L)
5722 FS : constant Node_Id := First (L);
5723 FL : constant Source_Ptr := Sloc (FS);
5728 -- LS points to either last statement, if statements are present
5729 -- or to the last declaration if there are no statements present.
5730 -- It is the node after which the pop's are generated.
5732 if Is_Non_Empty_List (Statements (H)) then
5733 LS := Last (Statements (H));
5740 Insert_List_Before_And_Analyze (FS, New_List (
5741 Make_Push_Constraint_Error_Label (FL),
5742 Make_Push_Program_Error_Label (FL),
5743 Make_Push_Storage_Error_Label (FL)));
5745 Insert_List_After_And_Analyze (LS, New_List (
5746 Make_Pop_Constraint_Error_Label (LL),
5747 Make_Pop_Program_Error_Label (LL),
5748 Make_Pop_Storage_Error_Label (LL)));
5752 -- Find entity for subprogram
5754 Body_Id := Defining_Entity (N);
5756 if Present (Corresponding_Spec (N)) then
5757 Spec_Id := Corresponding_Spec (N);
5762 -- Need poll on entry to subprogram if polling enabled. We only do this
5763 -- for non-empty subprograms, since it does not seem necessary to poll
5764 -- for a dummy null subprogram.
5766 if Is_Non_Empty_List (L) then
5768 -- Do not add a polling call if the subprogram is to be inlined by
5769 -- the back-end, to avoid repeated calls with multiple inlinings.
5771 if Is_Inlined (Spec_Id)
5772 and then Front_End_Inlining
5773 and then Optimization_Level > 1
5777 Generate_Poll_Call (First (L));
5781 -- If this is a Pure function which has any parameters whose root type
5782 -- is System.Address, reset the Pure indication, since it will likely
5783 -- cause incorrect code to be generated as the parameter is probably
5784 -- a pointer, and the fact that the same pointer is passed does not mean
5785 -- that the same value is being referenced.
5787 -- Note that if the programmer gave an explicit Pure_Function pragma,
5788 -- then we believe the programmer, and leave the subprogram Pure.
5790 -- This code should probably be at the freeze point, so that it happens
5791 -- even on a -gnatc (or more importantly -gnatt) compile, so that the
5792 -- semantic tree has Is_Pure set properly ???
5794 if Is_Pure (Spec_Id)
5795 and then Is_Subprogram (Spec_Id)
5796 and then not Has_Pragma_Pure_Function (Spec_Id)
5802 F := First_Formal (Spec_Id);
5803 while Present (F) loop
5804 if Is_Descendent_Of_Address (Etype (F))
5806 -- Note that this test is being made in the body of the
5807 -- subprogram, not the spec, so we are testing the full
5808 -- type for being limited here, as required.
5810 or else Is_Limited_Type (Etype (F))
5812 Set_Is_Pure (Spec_Id, False);
5814 if Spec_Id /= Body_Id then
5815 Set_Is_Pure (Body_Id, False);
5826 -- Initialize any scalar OUT args if Initialize/Normalize_Scalars
5828 if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then
5833 -- Loop through formals
5835 F := First_Formal (Spec_Id);
5836 while Present (F) loop
5837 if Is_Scalar_Type (Etype (F))
5838 and then Ekind (F) = E_Out_Parameter
5840 Check_Restriction (No_Default_Initialization, F);
5842 -- Insert the initialization. We turn off validity checks
5843 -- for this assignment, since we do not want any check on
5844 -- the initial value itself (which may well be invalid).
5846 Insert_Before_And_Analyze (First (L),
5847 Make_Assignment_Statement (Loc,
5848 Name => New_Occurrence_Of (F, Loc),
5849 Expression => Get_Simple_Init_Val (Etype (F), N)),
5850 Suppress => Validity_Check);
5858 -- Clear out statement list for stubbed procedure
5860 if Present (Corresponding_Spec (N)) then
5861 Set_Elaboration_Flag (N, Spec_Id);
5863 if Convention (Spec_Id) = Convention_Stubbed
5864 or else Is_Eliminated (Spec_Id)
5866 Set_Declarations (N, Empty_List);
5867 Set_Handled_Statement_Sequence (N,
5868 Make_Handled_Sequence_Of_Statements (Loc,
5869 Statements => New_List (Make_Null_Statement (Loc))));
5874 -- Create a set of discriminals for the next protected subprogram body
5876 if Is_List_Member (N)
5877 and then Present (Parent (List_Containing (N)))
5878 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
5879 and then Present (Next_Protected_Operation (N))
5881 Set_Discriminals (Parent (Base_Type (Scope (Spec_Id))));
5884 -- Returns_By_Ref flag is normally set when the subprogram is frozen but
5885 -- subprograms with no specs are not frozen.
5888 Typ : constant Entity_Id := Etype (Spec_Id);
5889 Utyp : constant Entity_Id := Underlying_Type (Typ);
5892 if not Acts_As_Spec (N)
5893 and then Nkind (Parent (Parent (Spec_Id))) /=
5894 N_Subprogram_Body_Stub
5898 elsif Is_Immutably_Limited_Type (Typ) then
5899 Set_Returns_By_Ref (Spec_Id);
5901 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
5902 Set_Returns_By_Ref (Spec_Id);
5906 -- For a procedure, we add a return for all possible syntactic ends of
5909 if Ekind_In (Spec_Id, E_Procedure, E_Generic_Procedure) then
5910 Add_Return (Statements (H));
5912 if Present (Exception_Handlers (H)) then
5913 Except_H := First_Non_Pragma (Exception_Handlers (H));
5914 while Present (Except_H) loop
5915 Add_Return (Statements (Except_H));
5916 Next_Non_Pragma (Except_H);
5920 -- For a function, we must deal with the case where there is at least
5921 -- one missing return. What we do is to wrap the entire body of the
5922 -- function in a block:
5935 -- raise Program_Error;
5938 -- This approach is necessary because the raise must be signalled to the
5939 -- caller, not handled by any local handler (RM 6.4(11)).
5941 -- Note: we do not need to analyze the constructed sequence here, since
5942 -- it has no handler, and an attempt to analyze the handled statement
5943 -- sequence twice is risky in various ways (e.g. the issue of expanding
5944 -- cleanup actions twice).
5946 elsif Has_Missing_Return (Spec_Id) then
5948 Hloc : constant Source_Ptr := Sloc (H);
5949 Blok : constant Node_Id :=
5950 Make_Block_Statement (Hloc,
5951 Handled_Statement_Sequence => H);
5952 Rais : constant Node_Id :=
5953 Make_Raise_Program_Error (Hloc,
5954 Reason => PE_Missing_Return);
5957 Set_Handled_Statement_Sequence (N,
5958 Make_Handled_Sequence_Of_Statements (Hloc,
5959 Statements => New_List (Blok, Rais)));
5961 Push_Scope (Spec_Id);
5968 -- If subprogram contains a parameterless recursive call, then we may
5969 -- have an infinite recursion, so see if we can generate code to check
5970 -- for this possibility if storage checks are not suppressed.
5972 if Ekind (Spec_Id) = E_Procedure
5973 and then Has_Recursive_Call (Spec_Id)
5974 and then not Storage_Checks_Suppressed (Spec_Id)
5976 Detect_Infinite_Recursion (N, Spec_Id);
5979 -- Set to encode entity names in package body before gigi is called
5981 Qualify_Entity_Names (N);
5982 end Expand_N_Subprogram_Body;
5984 -----------------------------------
5985 -- Expand_N_Subprogram_Body_Stub --
5986 -----------------------------------
5988 procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is
5990 if Present (Corresponding_Body (N)) then
5991 Expand_N_Subprogram_Body (
5992 Unit_Declaration_Node (Corresponding_Body (N)));
5994 end Expand_N_Subprogram_Body_Stub;
5996 -------------------------------------
5997 -- Expand_N_Subprogram_Declaration --
5998 -------------------------------------
6000 -- If the declaration appears within a protected body, it is a private
6001 -- operation of the protected type. We must create the corresponding
6002 -- protected subprogram an associated formals. For a normal protected
6003 -- operation, this is done when expanding the protected type declaration.
6005 -- If the declaration is for a null procedure, emit null body
6007 procedure Expand_N_Subprogram_Declaration (N : Node_Id) is
6008 Loc : constant Source_Ptr := Sloc (N);
6009 Subp : constant Entity_Id := Defining_Entity (N);
6010 Scop : constant Entity_Id := Scope (Subp);
6011 Prot_Decl : Node_Id;
6013 Prot_Id : Entity_Id;
6016 -- In SPARK, subprogram declarations are only allowed in package
6019 if Nkind (Parent (N)) /= N_Package_Specification then
6020 if Nkind (Parent (N)) = N_Compilation_Unit then
6021 Check_SPARK_Restriction
6022 ("subprogram declaration is not a library item", N);
6024 elsif Present (Next (N))
6025 and then Nkind (Next (N)) = N_Pragma
6026 and then Get_Pragma_Id (Pragma_Name (Next (N))) = Pragma_Import
6028 -- In SPARK, subprogram declarations are also permitted in
6029 -- declarative parts when immediately followed by a corresponding
6030 -- pragma Import. We only check here that there is some pragma
6035 Check_SPARK_Restriction
6036 ("subprogram declaration is not allowed here", N);
6040 -- Deal with case of protected subprogram. Do not generate protected
6041 -- operation if operation is flagged as eliminated.
6043 if Is_List_Member (N)
6044 and then Present (Parent (List_Containing (N)))
6045 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
6046 and then Is_Protected_Type (Scop)
6048 if No (Protected_Body_Subprogram (Subp))
6049 and then not Is_Eliminated (Subp)
6052 Make_Subprogram_Declaration (Loc,
6054 Build_Protected_Sub_Specification
6055 (N, Scop, Unprotected_Mode));
6057 -- The protected subprogram is declared outside of the protected
6058 -- body. Given that the body has frozen all entities so far, we
6059 -- analyze the subprogram and perform freezing actions explicitly.
6060 -- including the generation of an explicit freeze node, to ensure
6061 -- that gigi has the proper order of elaboration.
6062 -- If the body is a subunit, the insertion point is before the
6063 -- stub in the parent.
6065 Prot_Bod := Parent (List_Containing (N));
6067 if Nkind (Parent (Prot_Bod)) = N_Subunit then
6068 Prot_Bod := Corresponding_Stub (Parent (Prot_Bod));
6071 Insert_Before (Prot_Bod, Prot_Decl);
6072 Prot_Id := Defining_Unit_Name (Specification (Prot_Decl));
6073 Set_Has_Delayed_Freeze (Prot_Id);
6075 Push_Scope (Scope (Scop));
6076 Analyze (Prot_Decl);
6077 Freeze_Before (N, Prot_Id);
6078 Set_Protected_Body_Subprogram (Subp, Prot_Id);
6080 -- Create protected operation as well. Even though the operation
6081 -- is only accessible within the body, it is possible to make it
6082 -- available outside of the protected object by using 'Access to
6083 -- provide a callback, so build protected version in all cases.
6086 Make_Subprogram_Declaration (Loc,
6088 Build_Protected_Sub_Specification (N, Scop, Protected_Mode));
6089 Insert_Before (Prot_Bod, Prot_Decl);
6090 Analyze (Prot_Decl);
6095 -- Ada 2005 (AI-348): Generate body for a null procedure. In most
6096 -- cases this is superfluous because calls to it will be automatically
6097 -- inlined, but we definitely need the body if preconditions for the
6098 -- procedure are present.
6100 elsif Nkind (Specification (N)) = N_Procedure_Specification
6101 and then Null_Present (Specification (N))
6104 Bod : constant Node_Id := Body_To_Inline (N);
6107 Set_Has_Completion (Subp, False);
6108 Append_Freeze_Action (Subp, Bod);
6110 -- The body now contains raise statements, so calls to it will
6113 Set_Is_Inlined (Subp, False);
6116 end Expand_N_Subprogram_Declaration;
6118 --------------------------------
6119 -- Expand_Non_Function_Return --
6120 --------------------------------
6122 procedure Expand_Non_Function_Return (N : Node_Id) is
6123 pragma Assert (No (Expression (N)));
6125 Loc : constant Source_Ptr := Sloc (N);
6126 Scope_Id : Entity_Id :=
6127 Return_Applies_To (Return_Statement_Entity (N));
6128 Kind : constant Entity_Kind := Ekind (Scope_Id);
6131 Goto_Stat : Node_Id;
6135 -- Call _Postconditions procedure if procedure with active
6136 -- postconditions. Here, we use the Postcondition_Proc attribute,
6137 -- which is needed for implicitly-generated returns. Functions
6138 -- never have implicitly-generated returns, and there's no
6139 -- room for Postcondition_Proc in E_Function, so we look up the
6140 -- identifier Name_uPostconditions for function returns (see
6141 -- Expand_Simple_Function_Return).
6143 if Ekind (Scope_Id) = E_Procedure
6144 and then Has_Postconditions (Scope_Id)
6146 pragma Assert (Present (Postcondition_Proc (Scope_Id)));
6148 Make_Procedure_Call_Statement (Loc,
6149 Name => New_Reference_To (Postcondition_Proc (Scope_Id), Loc)));
6152 -- If it is a return from a procedure do no extra steps
6154 if Kind = E_Procedure or else Kind = E_Generic_Procedure then
6157 -- If it is a nested return within an extended one, replace it with a
6158 -- return of the previously declared return object.
6160 elsif Kind = E_Return_Statement then
6162 Make_Simple_Return_Statement (Loc,
6164 New_Occurrence_Of (First_Entity (Scope_Id), Loc)));
6165 Set_Comes_From_Extended_Return_Statement (N);
6166 Set_Return_Statement_Entity (N, Scope_Id);
6167 Expand_Simple_Function_Return (N);
6171 pragma Assert (Is_Entry (Scope_Id));
6173 -- Look at the enclosing block to see whether the return is from an
6174 -- accept statement or an entry body.
6176 for J in reverse 0 .. Scope_Stack.Last loop
6177 Scope_Id := Scope_Stack.Table (J).Entity;
6178 exit when Is_Concurrent_Type (Scope_Id);
6181 -- If it is a return from accept statement it is expanded as call to
6182 -- RTS Complete_Rendezvous and a goto to the end of the accept body.
6184 -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept,
6185 -- Expand_N_Accept_Alternative in exp_ch9.adb)
6187 if Is_Task_Type (Scope_Id) then
6190 Make_Procedure_Call_Statement (Loc,
6191 Name => New_Reference_To (RTE (RE_Complete_Rendezvous), Loc));
6192 Insert_Before (N, Call);
6193 -- why not insert actions here???
6196 Acc_Stat := Parent (N);
6197 while Nkind (Acc_Stat) /= N_Accept_Statement loop
6198 Acc_Stat := Parent (Acc_Stat);
6201 Lab_Node := Last (Statements
6202 (Handled_Statement_Sequence (Acc_Stat)));
6204 Goto_Stat := Make_Goto_Statement (Loc,
6205 Name => New_Occurrence_Of
6206 (Entity (Identifier (Lab_Node)), Loc));
6208 Set_Analyzed (Goto_Stat);
6210 Rewrite (N, Goto_Stat);
6213 -- If it is a return from an entry body, put a Complete_Entry_Body call
6214 -- in front of the return.
6216 elsif Is_Protected_Type (Scope_Id) then
6218 Make_Procedure_Call_Statement (Loc,
6220 New_Reference_To (RTE (RE_Complete_Entry_Body), Loc),
6221 Parameter_Associations => New_List (
6222 Make_Attribute_Reference (Loc,
6225 (Find_Protection_Object (Current_Scope), Loc),
6226 Attribute_Name => Name_Unchecked_Access)));
6228 Insert_Before (N, Call);
6231 end Expand_Non_Function_Return;
6233 ---------------------------------------
6234 -- Expand_Protected_Object_Reference --
6235 ---------------------------------------
6237 function Expand_Protected_Object_Reference
6239 Scop : Entity_Id) return Node_Id
6241 Loc : constant Source_Ptr := Sloc (N);
6248 Rec := Make_Identifier (Loc, Name_uObject);
6249 Set_Etype (Rec, Corresponding_Record_Type (Scop));
6251 -- Find enclosing protected operation, and retrieve its first parameter,
6252 -- which denotes the enclosing protected object. If the enclosing
6253 -- operation is an entry, we are immediately within the protected body,
6254 -- and we can retrieve the object from the service entries procedure. A
6255 -- barrier function has the same signature as an entry. A barrier
6256 -- function is compiled within the protected object, but unlike
6257 -- protected operations its never needs locks, so that its protected
6258 -- body subprogram points to itself.
6260 Proc := Current_Scope;
6261 while Present (Proc)
6262 and then Scope (Proc) /= Scop
6264 Proc := Scope (Proc);
6267 Corr := Protected_Body_Subprogram (Proc);
6271 -- Previous error left expansion incomplete.
6272 -- Nothing to do on this call.
6279 (First (Parameter_Specifications (Parent (Corr))));
6281 if Is_Subprogram (Proc)
6282 and then Proc /= Corr
6284 -- Protected function or procedure
6286 Set_Entity (Rec, Param);
6288 -- Rec is a reference to an entity which will not be in scope when
6289 -- the call is reanalyzed, and needs no further analysis.
6294 -- Entry or barrier function for entry body. The first parameter of
6295 -- the entry body procedure is pointer to the object. We create a
6296 -- local variable of the proper type, duplicating what is done to
6297 -- define _object later on.
6301 Obj_Ptr : constant Entity_Id := Make_Temporary (Loc, 'T');
6305 Make_Full_Type_Declaration (Loc,
6306 Defining_Identifier => Obj_Ptr,
6308 Make_Access_To_Object_Definition (Loc,
6309 Subtype_Indication =>
6311 (Corresponding_Record_Type (Scop), Loc))));
6313 Insert_Actions (N, Decls);
6314 Freeze_Before (N, Obj_Ptr);
6317 Make_Explicit_Dereference (Loc,
6319 Unchecked_Convert_To (Obj_Ptr,
6320 New_Occurrence_Of (Param, Loc)));
6322 -- Analyze new actual. Other actuals in calls are already analyzed
6323 -- and the list of actuals is not reanalyzed after rewriting.
6325 Set_Parent (Rec, N);
6331 end Expand_Protected_Object_Reference;
6333 --------------------------------------
6334 -- Expand_Protected_Subprogram_Call --
6335 --------------------------------------
6337 procedure Expand_Protected_Subprogram_Call
6345 -- If the protected object is not an enclosing scope, this is an inter-
6346 -- object function call. Inter-object procedure calls are expanded by
6347 -- Exp_Ch9.Build_Simple_Entry_Call. The call is intra-object only if the
6348 -- subprogram being called is in the protected body being compiled, and
6349 -- if the protected object in the call is statically the enclosing type.
6350 -- The object may be an component of some other data structure, in which
6351 -- case this must be handled as an inter-object call.
6353 if not In_Open_Scopes (Scop)
6354 or else not Is_Entity_Name (Name (N))
6356 if Nkind (Name (N)) = N_Selected_Component then
6357 Rec := Prefix (Name (N));
6360 pragma Assert (Nkind (Name (N)) = N_Indexed_Component);
6361 Rec := Prefix (Prefix (Name (N)));
6364 Build_Protected_Subprogram_Call (N,
6365 Name => New_Occurrence_Of (Subp, Sloc (N)),
6366 Rec => Convert_Concurrent (Rec, Etype (Rec)),
6370 Rec := Expand_Protected_Object_Reference (N, Scop);
6376 Build_Protected_Subprogram_Call (N,
6383 -- If it is a function call it can appear in elaboration code and
6384 -- the called entity must be frozen here.
6386 if Ekind (Subp) = E_Function then
6387 Freeze_Expression (Name (N));
6390 -- Analyze and resolve the new call. The actuals have already been
6391 -- resolved, but expansion of a function call will add extra actuals
6392 -- if needed. Analysis of a procedure call already includes resolution.
6396 if Ekind (Subp) = E_Function then
6397 Resolve (N, Etype (Subp));
6399 end Expand_Protected_Subprogram_Call;
6401 --------------------------------------------
6402 -- Has_Unconstrained_Access_Discriminants --
6403 --------------------------------------------
6405 function Has_Unconstrained_Access_Discriminants
6406 (Subtyp : Entity_Id) return Boolean
6411 if Has_Discriminants (Subtyp)
6412 and then not Is_Constrained (Subtyp)
6414 Discr := First_Discriminant (Subtyp);
6415 while Present (Discr) loop
6416 if Ekind (Etype (Discr)) = E_Anonymous_Access_Type then
6420 Next_Discriminant (Discr);
6425 end Has_Unconstrained_Access_Discriminants;
6427 -----------------------------------
6428 -- Expand_Simple_Function_Return --
6429 -----------------------------------
6431 -- The "simple" comes from the syntax rule simple_return_statement. The
6432 -- semantics are not at all simple!
6434 procedure Expand_Simple_Function_Return (N : Node_Id) is
6435 Loc : constant Source_Ptr := Sloc (N);
6437 Scope_Id : constant Entity_Id :=
6438 Return_Applies_To (Return_Statement_Entity (N));
6439 -- The function we are returning from
6441 R_Type : constant Entity_Id := Etype (Scope_Id);
6442 -- The result type of the function
6444 Utyp : constant Entity_Id := Underlying_Type (R_Type);
6446 Exp : constant Node_Id := Expression (N);
6447 pragma Assert (Present (Exp));
6449 Exptyp : constant Entity_Id := Etype (Exp);
6450 -- The type of the expression (not necessarily the same as R_Type)
6452 Subtype_Ind : Node_Id;
6453 -- If the result type of the function is class-wide and the expression
6454 -- has a specific type, then we use the expression's type as the type of
6455 -- the return object. In cases where the expression is an aggregate that
6456 -- is built in place, this avoids the need for an expensive conversion
6457 -- of the return object to the specific type on assignments to the
6458 -- individual components.
6461 if Is_Class_Wide_Type (R_Type)
6462 and then not Is_Class_Wide_Type (Etype (Exp))
6464 Subtype_Ind := New_Occurrence_Of (Etype (Exp), Loc);
6466 Subtype_Ind := New_Occurrence_Of (R_Type, Loc);
6469 -- For the case of a simple return that does not come from an extended
6470 -- return, in the case of Ada 2005 where we are returning a limited
6471 -- type, we rewrite "return <expression>;" to be:
6473 -- return _anon_ : <return_subtype> := <expression>
6475 -- The expansion produced by Expand_N_Extended_Return_Statement will
6476 -- contain simple return statements (for example, a block containing
6477 -- simple return of the return object), which brings us back here with
6478 -- Comes_From_Extended_Return_Statement set. The reason for the barrier
6479 -- checking for a simple return that does not come from an extended
6480 -- return is to avoid this infinite recursion.
6482 -- The reason for this design is that for Ada 2005 limited returns, we
6483 -- need to reify the return object, so we can build it "in place", and
6484 -- we need a block statement to hang finalization and tasking stuff.
6486 -- ??? In order to avoid disruption, we avoid translating to extended
6487 -- return except in the cases where we really need to (Ada 2005 for
6488 -- inherently limited). We might prefer to do this translation in all
6489 -- cases (except perhaps for the case of Ada 95 inherently limited),
6490 -- in order to fully exercise the Expand_N_Extended_Return_Statement
6491 -- code. This would also allow us to do the build-in-place optimization
6492 -- for efficiency even in cases where it is semantically not required.
6494 -- As before, we check the type of the return expression rather than the
6495 -- return type of the function, because the latter may be a limited
6496 -- class-wide interface type, which is not a limited type, even though
6497 -- the type of the expression may be.
6499 if not Comes_From_Extended_Return_Statement (N)
6500 and then Is_Immutably_Limited_Type (Etype (Expression (N)))
6501 and then Ada_Version >= Ada_2005
6502 and then not Debug_Flag_Dot_L
6505 Return_Object_Entity : constant Entity_Id :=
6506 Make_Temporary (Loc, 'R', Exp);
6507 Obj_Decl : constant Node_Id :=
6508 Make_Object_Declaration (Loc,
6509 Defining_Identifier => Return_Object_Entity,
6510 Object_Definition => Subtype_Ind,
6513 Ext : constant Node_Id := Make_Extended_Return_Statement (Loc,
6514 Return_Object_Declarations => New_List (Obj_Decl));
6515 -- Do not perform this high-level optimization if the result type
6516 -- is an interface because the "this" pointer must be displaced.
6525 -- Here we have a simple return statement that is part of the expansion
6526 -- of an extended return statement (either written by the user, or
6527 -- generated by the above code).
6529 -- Always normalize C/Fortran boolean result. This is not always needed,
6530 -- but it seems a good idea to minimize the passing around of non-
6531 -- normalized values, and in any case this handles the processing of
6532 -- barrier functions for protected types, which turn the condition into
6533 -- a return statement.
6535 if Is_Boolean_Type (Exptyp)
6536 and then Nonzero_Is_True (Exptyp)
6538 Adjust_Condition (Exp);
6539 Adjust_Result_Type (Exp, Exptyp);
6542 -- Do validity check if enabled for returns
6544 if Validity_Checks_On
6545 and then Validity_Check_Returns
6550 -- Check the result expression of a scalar function against the subtype
6551 -- of the function by inserting a conversion. This conversion must
6552 -- eventually be performed for other classes of types, but for now it's
6553 -- only done for scalars.
6556 if Is_Scalar_Type (Exptyp) then
6557 Rewrite (Exp, Convert_To (R_Type, Exp));
6559 -- The expression is resolved to ensure that the conversion gets
6560 -- expanded to generate a possible constraint check.
6562 Analyze_And_Resolve (Exp, R_Type);
6565 -- Deal with returning variable length objects and controlled types
6567 -- Nothing to do if we are returning by reference, or this is not a
6568 -- type that requires special processing (indicated by the fact that
6569 -- it requires a cleanup scope for the secondary stack case).
6571 if Is_Immutably_Limited_Type (Exptyp)
6572 or else Is_Limited_Interface (Exptyp)
6576 elsif not Requires_Transient_Scope (R_Type) then
6578 -- Mutable records with no variable length components are not
6579 -- returned on the sec-stack, so we need to make sure that the
6580 -- backend will only copy back the size of the actual value, and not
6581 -- the maximum size. We create an actual subtype for this purpose.
6584 Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exptyp));
6588 if Has_Discriminants (Ubt)
6589 and then not Is_Constrained (Ubt)
6590 and then not Has_Unchecked_Union (Ubt)
6592 Decl := Build_Actual_Subtype (Ubt, Exp);
6593 Ent := Defining_Identifier (Decl);
6594 Insert_Action (Exp, Decl);
6595 Rewrite (Exp, Unchecked_Convert_To (Ent, Exp));
6596 Analyze_And_Resolve (Exp);
6600 -- Here if secondary stack is used
6603 -- Make sure that no surrounding block will reclaim the secondary
6604 -- stack on which we are going to put the result. Not only may this
6605 -- introduce secondary stack leaks but worse, if the reclamation is
6606 -- done too early, then the result we are returning may get
6613 while Ekind (S) = E_Block or else Ekind (S) = E_Loop loop
6614 Set_Sec_Stack_Needed_For_Return (S, True);
6615 S := Enclosing_Dynamic_Scope (S);
6619 -- Optimize the case where the result is a function call. In this
6620 -- case either the result is already on the secondary stack, or is
6621 -- already being returned with the stack pointer depressed and no
6622 -- further processing is required except to set the By_Ref flag
6623 -- to ensure that gigi does not attempt an extra unnecessary copy.
6624 -- (actually not just unnecessary but harmfully wrong in the case
6625 -- of a controlled type, where gigi does not know how to do a copy).
6626 -- To make up for a gcc 2.8.1 deficiency (???), we perform the copy
6627 -- for array types if the constrained status of the target type is
6628 -- different from that of the expression.
6630 if Requires_Transient_Scope (Exptyp)
6632 (not Is_Array_Type (Exptyp)
6633 or else Is_Constrained (Exptyp) = Is_Constrained (R_Type)
6634 or else CW_Or_Has_Controlled_Part (Utyp))
6635 and then Nkind (Exp) = N_Function_Call
6639 -- Remove side effects from the expression now so that other parts
6640 -- of the expander do not have to reanalyze this node without this
6643 Rewrite (Exp, Duplicate_Subexpr_No_Checks (Exp));
6645 -- For controlled types, do the allocation on the secondary stack
6646 -- manually in order to call adjust at the right time:
6648 -- type Anon1 is access R_Type;
6649 -- for Anon1'Storage_pool use ss_pool;
6650 -- Anon2 : anon1 := new R_Type'(expr);
6651 -- return Anon2.all;
6653 -- We do the same for classwide types that are not potentially
6654 -- controlled (by the virtue of restriction No_Finalization) because
6655 -- gigi is not able to properly allocate class-wide types.
6657 elsif CW_Or_Has_Controlled_Part (Utyp) then
6659 Loc : constant Source_Ptr := Sloc (N);
6660 Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
6661 Alloc_Node : Node_Id;
6665 Set_Ekind (Acc_Typ, E_Access_Type);
6667 Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool));
6669 -- This is an allocator for the secondary stack, and it's fine
6670 -- to have Comes_From_Source set False on it, as gigi knows not
6671 -- to flag it as a violation of No_Implicit_Heap_Allocations.
6674 Make_Allocator (Loc,
6676 Make_Qualified_Expression (Loc,
6677 Subtype_Mark => New_Reference_To (Etype (Exp), Loc),
6678 Expression => Relocate_Node (Exp)));
6680 -- We do not want discriminant checks on the declaration,
6681 -- given that it gets its value from the allocator.
6683 Set_No_Initialization (Alloc_Node);
6685 Temp := Make_Temporary (Loc, 'R', Alloc_Node);
6687 Insert_List_Before_And_Analyze (N, New_List (
6688 Make_Full_Type_Declaration (Loc,
6689 Defining_Identifier => Acc_Typ,
6691 Make_Access_To_Object_Definition (Loc,
6692 Subtype_Indication => Subtype_Ind)),
6694 Make_Object_Declaration (Loc,
6695 Defining_Identifier => Temp,
6696 Object_Definition => New_Reference_To (Acc_Typ, Loc),
6697 Expression => Alloc_Node)));
6700 Make_Explicit_Dereference (Loc,
6701 Prefix => New_Reference_To (Temp, Loc)));
6703 -- Ada 2005 (AI-251): If the type of the returned object is
6704 -- an interface then add an implicit type conversion to force
6705 -- displacement of the "this" pointer.
6707 if Is_Interface (R_Type) then
6708 Rewrite (Exp, Convert_To (R_Type, Relocate_Node (Exp)));
6711 Analyze_And_Resolve (Exp, R_Type);
6714 -- Otherwise use the gigi mechanism to allocate result on the
6718 Check_Restriction (No_Secondary_Stack, N);
6719 Set_Storage_Pool (N, RTE (RE_SS_Pool));
6721 -- If we are generating code for the VM do not use
6722 -- SS_Allocate since everything is heap-allocated anyway.
6724 if VM_Target = No_VM then
6725 Set_Procedure_To_Call (N, RTE (RE_SS_Allocate));
6730 -- Implement the rules of 6.5(8-10), which require a tag check in
6731 -- the case of a limited tagged return type, and tag reassignment for
6732 -- nonlimited tagged results. These actions are needed when the return
6733 -- type is a specific tagged type and the result expression is a
6734 -- conversion or a formal parameter, because in that case the tag of
6735 -- the expression might differ from the tag of the specific result type.
6737 if Is_Tagged_Type (Utyp)
6738 and then not Is_Class_Wide_Type (Utyp)
6739 and then (Nkind_In (Exp, N_Type_Conversion,
6740 N_Unchecked_Type_Conversion)
6741 or else (Is_Entity_Name (Exp)
6742 and then Ekind (Entity (Exp)) in Formal_Kind))
6744 -- When the return type is limited, perform a check that the tag of
6745 -- the result is the same as the tag of the return type.
6747 if Is_Limited_Type (R_Type) then
6749 Make_Raise_Constraint_Error (Loc,
6753 Make_Selected_Component (Loc,
6754 Prefix => Duplicate_Subexpr (Exp),
6755 Selector_Name => Make_Identifier (Loc, Name_uTag)),
6757 Make_Attribute_Reference (Loc,
6759 New_Occurrence_Of (Base_Type (Utyp), Loc),
6760 Attribute_Name => Name_Tag)),
6761 Reason => CE_Tag_Check_Failed));
6763 -- If the result type is a specific nonlimited tagged type, then we
6764 -- have to ensure that the tag of the result is that of the result
6765 -- type. This is handled by making a copy of the expression in
6766 -- the case where it might have a different tag, namely when the
6767 -- expression is a conversion or a formal parameter. We create a new
6768 -- object of the result type and initialize it from the expression,
6769 -- which will implicitly force the tag to be set appropriately.
6773 ExpR : constant Node_Id := Relocate_Node (Exp);
6774 Result_Id : constant Entity_Id :=
6775 Make_Temporary (Loc, 'R', ExpR);
6776 Result_Exp : constant Node_Id :=
6777 New_Reference_To (Result_Id, Loc);
6778 Result_Obj : constant Node_Id :=
6779 Make_Object_Declaration (Loc,
6780 Defining_Identifier => Result_Id,
6781 Object_Definition =>
6782 New_Reference_To (R_Type, Loc),
6783 Constant_Present => True,
6784 Expression => ExpR);
6787 Set_Assignment_OK (Result_Obj);
6788 Insert_Action (Exp, Result_Obj);
6790 Rewrite (Exp, Result_Exp);
6791 Analyze_And_Resolve (Exp, R_Type);
6795 -- Ada 2005 (AI-344): If the result type is class-wide, then insert
6796 -- a check that the level of the return expression's underlying type
6797 -- is not deeper than the level of the master enclosing the function.
6798 -- Always generate the check when the type of the return expression
6799 -- is class-wide, when it's a type conversion, or when it's a formal
6800 -- parameter. Otherwise, suppress the check in the case where the
6801 -- return expression has a specific type whose level is known not to
6802 -- be statically deeper than the function's result type.
6804 -- Note: accessibility check is skipped in the VM case, since there
6805 -- does not seem to be any practical way to implement this check.
6807 elsif Ada_Version >= Ada_2005
6808 and then Tagged_Type_Expansion
6809 and then Is_Class_Wide_Type (R_Type)
6810 and then not Scope_Suppress (Accessibility_Check)
6812 (Is_Class_Wide_Type (Etype (Exp))
6813 or else Nkind_In (Exp, N_Type_Conversion,
6814 N_Unchecked_Type_Conversion)
6815 or else (Is_Entity_Name (Exp)
6816 and then Ekind (Entity (Exp)) in Formal_Kind)
6817 or else Scope_Depth (Enclosing_Dynamic_Scope (Etype (Exp))) >
6818 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))
6824 -- Ada 2005 (AI-251): In class-wide interface objects we displace
6825 -- "this" to reference the base of the object. This is required to
6826 -- get access to the TSD of the object.
6828 if Is_Class_Wide_Type (Etype (Exp))
6829 and then Is_Interface (Etype (Exp))
6830 and then Nkind (Exp) = N_Explicit_Dereference
6833 Make_Explicit_Dereference (Loc,
6835 Unchecked_Convert_To (RTE (RE_Tag_Ptr),
6836 Make_Function_Call (Loc,
6838 New_Reference_To (RTE (RE_Base_Address), Loc),
6839 Parameter_Associations => New_List (
6840 Unchecked_Convert_To (RTE (RE_Address),
6841 Duplicate_Subexpr (Prefix (Exp)))))));
6844 Make_Attribute_Reference (Loc,
6845 Prefix => Duplicate_Subexpr (Exp),
6846 Attribute_Name => Name_Tag);
6850 Make_Raise_Program_Error (Loc,
6853 Left_Opnd => Build_Get_Access_Level (Loc, Tag_Node),
6855 Make_Integer_Literal (Loc,
6856 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))),
6857 Reason => PE_Accessibility_Check_Failed));
6860 -- AI05-0073: If function has a controlling access result, check that
6861 -- the tag of the return value, if it is not null, matches designated
6862 -- type of return type.
6863 -- The return expression is referenced twice in the code below, so
6864 -- it must be made free of side effects. Given that different compilers
6865 -- may evaluate these parameters in different order, both occurrences
6868 elsif Ekind (R_Type) = E_Anonymous_Access_Type
6869 and then Has_Controlling_Result (Scope_Id)
6872 Make_Raise_Constraint_Error (Loc,
6877 Left_Opnd => Duplicate_Subexpr (Exp),
6878 Right_Opnd => Make_Null (Loc)),
6880 Right_Opnd => Make_Op_Ne (Loc,
6882 Make_Selected_Component (Loc,
6883 Prefix => Duplicate_Subexpr (Exp),
6884 Selector_Name => Make_Identifier (Loc, Name_uTag)),
6887 Make_Attribute_Reference (Loc,
6889 New_Occurrence_Of (Designated_Type (R_Type), Loc),
6890 Attribute_Name => Name_Tag))),
6892 Reason => CE_Tag_Check_Failed),
6893 Suppress => All_Checks);
6896 -- AI05-0234: RM 6.5(21/3). Check access discriminants to
6897 -- ensure that the function result does not outlive an
6898 -- object designated by one of it discriminants.
6900 if Present (Extra_Accessibility_Of_Result (Scope_Id))
6901 and then Has_Unconstrained_Access_Discriminants (R_Type)
6904 Discrim_Source : Node_Id;
6906 procedure Check_Against_Result_Level (Level : Node_Id);
6907 -- Check the given accessibility level against the level
6908 -- determined by the point of call. (AI05-0234).
6910 --------------------------------
6911 -- Check_Against_Result_Level --
6912 --------------------------------
6914 procedure Check_Against_Result_Level (Level : Node_Id) is
6917 Make_Raise_Program_Error (Loc,
6923 (Extra_Accessibility_Of_Result (Scope_Id), Loc)),
6924 Reason => PE_Accessibility_Check_Failed));
6925 end Check_Against_Result_Level;
6928 Discrim_Source := Exp;
6929 while Nkind (Discrim_Source) = N_Qualified_Expression loop
6930 Discrim_Source := Expression (Discrim_Source);
6933 if Nkind (Discrim_Source) = N_Identifier
6934 and then Is_Return_Object (Entity (Discrim_Source))
6936 Discrim_Source := Entity (Discrim_Source);
6938 if Is_Constrained (Etype (Discrim_Source)) then
6939 Discrim_Source := Etype (Discrim_Source);
6941 Discrim_Source := Expression (Parent (Discrim_Source));
6944 elsif Nkind (Discrim_Source) = N_Identifier
6945 and then Nkind_In (Original_Node (Discrim_Source),
6946 N_Aggregate, N_Extension_Aggregate)
6948 Discrim_Source := Original_Node (Discrim_Source);
6950 elsif Nkind (Discrim_Source) = N_Explicit_Dereference and then
6951 Nkind (Original_Node (Discrim_Source)) = N_Function_Call
6953 Discrim_Source := Original_Node (Discrim_Source);
6956 while Nkind_In (Discrim_Source, N_Qualified_Expression,
6958 N_Unchecked_Type_Conversion)
6960 Discrim_Source := Expression (Discrim_Source);
6963 case Nkind (Discrim_Source) is
6964 when N_Defining_Identifier =>
6966 pragma Assert (Is_Composite_Type (Discrim_Source)
6967 and then Has_Discriminants (Discrim_Source)
6968 and then Is_Constrained (Discrim_Source));
6971 Discrim : Entity_Id :=
6972 First_Discriminant (Base_Type (R_Type));
6973 Disc_Elmt : Elmt_Id :=
6974 First_Elmt (Discriminant_Constraint
6978 if Ekind (Etype (Discrim)) =
6979 E_Anonymous_Access_Type
6981 Check_Against_Result_Level
6982 (Dynamic_Accessibility_Level (Node (Disc_Elmt)));
6985 Next_Elmt (Disc_Elmt);
6986 Next_Discriminant (Discrim);
6987 exit when not Present (Discrim);
6991 when N_Aggregate | N_Extension_Aggregate =>
6993 -- Unimplemented: extension aggregate case where discrims
6994 -- come from ancestor part, not extension part.
6997 Discrim : Entity_Id :=
6998 First_Discriminant (Base_Type (R_Type));
7000 Disc_Exp : Node_Id := Empty;
7002 Positionals_Exhausted
7003 : Boolean := not Present (Expressions
7006 function Associated_Expr
7007 (Comp_Id : Entity_Id;
7008 Associations : List_Id) return Node_Id;
7010 -- Given a component and a component associations list,
7011 -- locate the expression for that component; returns
7012 -- Empty if no such expression is found.
7014 ---------------------
7015 -- Associated_Expr --
7016 ---------------------
7018 function Associated_Expr
7019 (Comp_Id : Entity_Id;
7020 Associations : List_Id) return Node_Id
7026 -- Simple linear search seems ok here
7028 Assoc := First (Associations);
7029 while Present (Assoc) loop
7030 Choice := First (Choices (Assoc));
7031 while Present (Choice) loop
7032 if (Nkind (Choice) = N_Identifier
7033 and then Chars (Choice) = Chars (Comp_Id))
7034 or else (Nkind (Choice) = N_Others_Choice)
7036 return Expression (Assoc);
7046 end Associated_Expr;
7048 -- Start of processing for Expand_Simple_Function_Return
7051 if not Positionals_Exhausted then
7052 Disc_Exp := First (Expressions (Discrim_Source));
7056 if Positionals_Exhausted then
7060 Component_Associations (Discrim_Source));
7063 if Ekind (Etype (Discrim)) =
7064 E_Anonymous_Access_Type
7066 Check_Against_Result_Level
7067 (Dynamic_Accessibility_Level (Disc_Exp));
7070 Next_Discriminant (Discrim);
7071 exit when not Present (Discrim);
7073 if not Positionals_Exhausted then
7075 Positionals_Exhausted := not Present (Disc_Exp);
7080 when N_Function_Call =>
7082 -- No check needed (check performed by callee)
7089 Level : constant Node_Id :=
7090 Make_Integer_Literal (Loc,
7091 Object_Access_Level (Discrim_Source));
7094 -- Unimplemented: check for name prefix that includes
7095 -- a dereference of an access value with a dynamic
7096 -- accessibility level (e.g., an access param or a
7097 -- saooaaat) and use dynamic level in that case. For
7099 -- return Access_Param.all(Some_Index).Some_Component;
7102 Set_Etype (Level, Standard_Natural);
7103 Check_Against_Result_Level (Level);
7110 -- If we are returning an object that may not be bit-aligned, then copy
7111 -- the value into a temporary first. This copy may need to expand to a
7112 -- loop of component operations.
7114 if Is_Possibly_Unaligned_Slice (Exp)
7115 or else Is_Possibly_Unaligned_Object (Exp)
7118 ExpR : constant Node_Id := Relocate_Node (Exp);
7119 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
7122 Make_Object_Declaration (Loc,
7123 Defining_Identifier => Tnn,
7124 Constant_Present => True,
7125 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7126 Expression => ExpR),
7127 Suppress => All_Checks);
7128 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7132 -- Generate call to postcondition checks if they are present
7134 if Ekind (Scope_Id) = E_Function
7135 and then Has_Postconditions (Scope_Id)
7137 -- We are going to reference the returned value twice in this case,
7138 -- once in the call to _Postconditions, and once in the actual return
7139 -- statement, but we can't have side effects happening twice, and in
7140 -- any case for efficiency we don't want to do the computation twice.
7142 -- If the returned expression is an entity name, we don't need to
7143 -- worry since it is efficient and safe to reference it twice, that's
7144 -- also true for literals other than string literals, and for the
7145 -- case of X.all where X is an entity name.
7147 if Is_Entity_Name (Exp)
7148 or else Nkind_In (Exp, N_Character_Literal,
7151 or else (Nkind (Exp) = N_Explicit_Dereference
7152 and then Is_Entity_Name (Prefix (Exp)))
7156 -- Otherwise we are going to need a temporary to capture the value
7160 ExpR : constant Node_Id := Relocate_Node (Exp);
7161 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
7164 -- For a complex expression of an elementary type, capture
7165 -- value in the temporary and use it as the reference.
7167 if Is_Elementary_Type (R_Type) then
7169 Make_Object_Declaration (Loc,
7170 Defining_Identifier => Tnn,
7171 Constant_Present => True,
7172 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7173 Expression => ExpR),
7174 Suppress => All_Checks);
7176 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7178 -- If we have something we can rename, generate a renaming of
7179 -- the object and replace the expression with a reference
7181 elsif Is_Object_Reference (Exp) then
7183 Make_Object_Renaming_Declaration (Loc,
7184 Defining_Identifier => Tnn,
7185 Subtype_Mark => New_Occurrence_Of (R_Type, Loc),
7187 Suppress => All_Checks);
7189 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7191 -- Otherwise we have something like a string literal or an
7192 -- aggregate. We could copy the value, but that would be
7193 -- inefficient. Instead we make a reference to the value and
7194 -- capture this reference with a renaming, the expression is
7195 -- then replaced by a dereference of this renaming.
7198 -- For now, copy the value, since the code below does not
7199 -- seem to work correctly ???
7202 Make_Object_Declaration (Loc,
7203 Defining_Identifier => Tnn,
7204 Constant_Present => True,
7205 Object_Definition => New_Occurrence_Of (R_Type, Loc),
7206 Expression => Relocate_Node (Exp)),
7207 Suppress => All_Checks);
7209 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
7211 -- Insert_Action (Exp,
7212 -- Make_Object_Renaming_Declaration (Loc,
7213 -- Defining_Identifier => Tnn,
7214 -- Access_Definition =>
7215 -- Make_Access_Definition (Loc,
7216 -- All_Present => True,
7217 -- Subtype_Mark => New_Occurrence_Of (R_Type, Loc)),
7219 -- Make_Reference (Loc,
7220 -- Prefix => Relocate_Node (Exp))),
7221 -- Suppress => All_Checks);
7224 -- Make_Explicit_Dereference (Loc,
7225 -- Prefix => New_Occurrence_Of (Tnn, Loc)));
7230 -- Generate call to _postconditions
7233 Make_Procedure_Call_Statement (Loc,
7234 Name => Make_Identifier (Loc, Name_uPostconditions),
7235 Parameter_Associations => New_List (Duplicate_Subexpr (Exp))));
7238 -- Ada 2005 (AI-251): If this return statement corresponds with an
7239 -- simple return statement associated with an extended return statement
7240 -- and the type of the returned object is an interface then generate an
7241 -- implicit conversion to force displacement of the "this" pointer.
7243 if Ada_Version >= Ada_2005
7244 and then Comes_From_Extended_Return_Statement (N)
7245 and then Nkind (Expression (N)) = N_Identifier
7246 and then Is_Interface (Utyp)
7247 and then Utyp /= Underlying_Type (Exptyp)
7249 Rewrite (Exp, Convert_To (Utyp, Relocate_Node (Exp)));
7250 Analyze_And_Resolve (Exp);
7252 end Expand_Simple_Function_Return;
7254 --------------------------------
7255 -- Is_Build_In_Place_Function --
7256 --------------------------------
7258 function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is
7260 -- This function is called from Expand_Subtype_From_Expr during
7261 -- semantic analysis, even when expansion is off. In those cases
7262 -- the build_in_place expansion will not take place.
7264 if not Expander_Active then
7268 -- For now we test whether E denotes a function or access-to-function
7269 -- type whose result subtype is inherently limited. Later this test may
7270 -- be revised to allow composite nonlimited types. Functions with a
7271 -- foreign convention or whose result type has a foreign convention
7274 if Ekind_In (E, E_Function, E_Generic_Function)
7275 or else (Ekind (E) = E_Subprogram_Type
7276 and then Etype (E) /= Standard_Void_Type)
7278 -- Note: If you have Convention (C) on an inherently limited type,
7279 -- you're on your own. That is, the C code will have to be carefully
7280 -- written to know about the Ada conventions.
7282 if Has_Foreign_Convention (E)
7283 or else Has_Foreign_Convention (Etype (E))
7287 -- In Ada 2005 all functions with an inherently limited return type
7288 -- must be handled using a build-in-place profile, including the case
7289 -- of a function with a limited interface result, where the function
7290 -- may return objects of nonlimited descendants.
7293 return Is_Immutably_Limited_Type (Etype (E))
7294 and then Ada_Version >= Ada_2005
7295 and then not Debug_Flag_Dot_L;
7301 end Is_Build_In_Place_Function;
7303 -------------------------------------
7304 -- Is_Build_In_Place_Function_Call --
7305 -------------------------------------
7307 function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is
7308 Exp_Node : Node_Id := N;
7309 Function_Id : Entity_Id;
7312 -- Return False when the expander is inactive, since awareness of
7313 -- build-in-place treatment is only relevant during expansion. Note that
7314 -- Is_Build_In_Place_Function, which is called as part of this function,
7315 -- is also conditioned this way, but we need to check here as well to
7316 -- avoid blowing up on processing protected calls when expansion is
7317 -- disabled (such as with -gnatc) since those would trip over the raise
7318 -- of Program_Error below.
7320 if not Expander_Active then
7324 -- Step past qualification or unchecked conversion (the latter can occur
7325 -- in cases of calls to 'Input).
7327 if Nkind_In (Exp_Node, N_Qualified_Expression,
7328 N_Unchecked_Type_Conversion)
7330 Exp_Node := Expression (N);
7333 if Nkind (Exp_Node) /= N_Function_Call then
7337 -- In Alfa mode, build-in-place calls are not expanded, so that we
7338 -- may end up with a call that is neither resolved to an entity, nor
7339 -- an indirect call.
7344 elsif Is_Entity_Name (Name (Exp_Node)) then
7345 Function_Id := Entity (Name (Exp_Node));
7347 -- In the case of an explicitly dereferenced call, use the subprogram
7348 -- type generated for the dereference.
7350 elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then
7351 Function_Id := Etype (Name (Exp_Node));
7354 raise Program_Error;
7357 return Is_Build_In_Place_Function (Function_Id);
7359 end Is_Build_In_Place_Function_Call;
7361 -----------------------
7362 -- Freeze_Subprogram --
7363 -----------------------
7365 procedure Freeze_Subprogram (N : Node_Id) is
7366 Loc : constant Source_Ptr := Sloc (N);
7368 procedure Register_Predefined_DT_Entry (Prim : Entity_Id);
7369 -- (Ada 2005): Register a predefined primitive in all the secondary
7370 -- dispatch tables of its primitive type.
7372 ----------------------------------
7373 -- Register_Predefined_DT_Entry --
7374 ----------------------------------
7376 procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is
7377 Iface_DT_Ptr : Elmt_Id;
7378 Tagged_Typ : Entity_Id;
7379 Thunk_Id : Entity_Id;
7380 Thunk_Code : Node_Id;
7383 Tagged_Typ := Find_Dispatching_Type (Prim);
7385 if No (Access_Disp_Table (Tagged_Typ))
7386 or else not Has_Interfaces (Tagged_Typ)
7387 or else not RTE_Available (RE_Interface_Tag)
7388 or else Restriction_Active (No_Dispatching_Calls)
7393 -- Skip the first two access-to-dispatch-table pointers since they
7394 -- leads to the primary dispatch table (predefined DT and user
7395 -- defined DT). We are only concerned with the secondary dispatch
7396 -- table pointers. Note that the access-to- dispatch-table pointer
7397 -- corresponds to the first implemented interface retrieved below.
7400 Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ))));
7402 while Present (Iface_DT_Ptr)
7403 and then Ekind (Node (Iface_DT_Ptr)) = E_Constant
7405 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
7406 Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code);
7408 if Present (Thunk_Code) then
7409 Insert_Actions_After (N, New_List (
7412 Build_Set_Predefined_Prim_Op_Address (Loc,
7414 New_Reference_To (Node (Next_Elmt (Iface_DT_Ptr)), Loc),
7415 Position => DT_Position (Prim),
7417 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
7418 Make_Attribute_Reference (Loc,
7419 Prefix => New_Reference_To (Thunk_Id, Loc),
7420 Attribute_Name => Name_Unrestricted_Access))),
7422 Build_Set_Predefined_Prim_Op_Address (Loc,
7425 (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))),
7427 Position => DT_Position (Prim),
7429 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
7430 Make_Attribute_Reference (Loc,
7431 Prefix => New_Reference_To (Prim, Loc),
7432 Attribute_Name => Name_Unrestricted_Access)))));
7435 -- Skip the tag of the predefined primitives dispatch table
7437 Next_Elmt (Iface_DT_Ptr);
7438 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
7440 -- Skip tag of the no-thunks dispatch table
7442 Next_Elmt (Iface_DT_Ptr);
7443 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
7445 -- Skip tag of predefined primitives no-thunks dispatch table
7447 Next_Elmt (Iface_DT_Ptr);
7448 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
7450 Next_Elmt (Iface_DT_Ptr);
7452 end Register_Predefined_DT_Entry;
7456 Subp : constant Entity_Id := Entity (N);
7458 -- Start of processing for Freeze_Subprogram
7461 -- We suppress the initialization of the dispatch table entry when
7462 -- VM_Target because the dispatching mechanism is handled internally
7465 if Is_Dispatching_Operation (Subp)
7466 and then not Is_Abstract_Subprogram (Subp)
7467 and then Present (DTC_Entity (Subp))
7468 and then Present (Scope (DTC_Entity (Subp)))
7469 and then Tagged_Type_Expansion
7470 and then not Restriction_Active (No_Dispatching_Calls)
7471 and then RTE_Available (RE_Tag)
7474 Typ : constant Entity_Id := Scope (DTC_Entity (Subp));
7477 -- Handle private overridden primitives
7479 if not Is_CPP_Class (Typ) then
7480 Check_Overriding_Operation (Subp);
7483 -- We assume that imported CPP primitives correspond with objects
7484 -- whose constructor is in the CPP side; therefore we don't need
7485 -- to generate code to register them in the dispatch table.
7487 if Is_CPP_Class (Typ) then
7490 -- Handle CPP primitives found in derivations of CPP_Class types.
7491 -- These primitives must have been inherited from some parent, and
7492 -- there is no need to register them in the dispatch table because
7493 -- Build_Inherit_Prims takes care of the initialization of these
7496 elsif Is_Imported (Subp)
7497 and then (Convention (Subp) = Convention_CPP
7498 or else Convention (Subp) = Convention_C)
7502 -- Generate code to register the primitive in non statically
7503 -- allocated dispatch tables
7505 elsif not Building_Static_DT (Scope (DTC_Entity (Subp))) then
7507 -- When a primitive is frozen, enter its name in its dispatch
7510 if not Is_Interface (Typ)
7511 or else Present (Interface_Alias (Subp))
7513 if Is_Predefined_Dispatching_Operation (Subp) then
7514 Register_Predefined_DT_Entry (Subp);
7517 Insert_Actions_After (N,
7518 Register_Primitive (Loc, Prim => Subp));
7524 -- Mark functions that return by reference. Note that it cannot be part
7525 -- of the normal semantic analysis of the spec since the underlying
7526 -- returned type may not be known yet (for private types).
7529 Typ : constant Entity_Id := Etype (Subp);
7530 Utyp : constant Entity_Id := Underlying_Type (Typ);
7532 if Is_Immutably_Limited_Type (Typ) then
7533 Set_Returns_By_Ref (Subp);
7534 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
7535 Set_Returns_By_Ref (Subp);
7538 end Freeze_Subprogram;
7540 -----------------------
7541 -- Is_Null_Procedure --
7542 -----------------------
7544 function Is_Null_Procedure (Subp : Entity_Id) return Boolean is
7545 Decl : constant Node_Id := Unit_Declaration_Node (Subp);
7548 if Ekind (Subp) /= E_Procedure then
7551 -- Check if this is a declared null procedure
7553 elsif Nkind (Decl) = N_Subprogram_Declaration then
7554 if not Null_Present (Specification (Decl)) then
7557 elsif No (Body_To_Inline (Decl)) then
7560 -- Check if the body contains only a null statement, followed by
7561 -- the return statement added during expansion.
7565 Orig_Bod : constant Node_Id := Body_To_Inline (Decl);
7571 if Nkind (Orig_Bod) /= N_Subprogram_Body then
7574 -- We must skip SCIL nodes because they are currently
7575 -- implemented as special N_Null_Statement nodes.
7579 (Statements (Handled_Statement_Sequence (Orig_Bod)));
7580 Stat2 := Next_Non_SCIL_Node (Stat);
7583 Is_Empty_List (Declarations (Orig_Bod))
7584 and then Nkind (Stat) = N_Null_Statement
7588 (Nkind (Stat2) = N_Simple_Return_Statement
7589 and then No (Next (Stat2))));
7597 end Is_Null_Procedure;
7599 -------------------------------------------
7600 -- Make_Build_In_Place_Call_In_Allocator --
7601 -------------------------------------------
7603 procedure Make_Build_In_Place_Call_In_Allocator
7604 (Allocator : Node_Id;
7605 Function_Call : Node_Id)
7607 Acc_Type : constant Entity_Id := Etype (Allocator);
7609 Func_Call : Node_Id := Function_Call;
7610 Function_Id : Entity_Id;
7611 Result_Subt : Entity_Id;
7612 New_Allocator : Node_Id;
7613 Return_Obj_Access : Entity_Id;
7616 -- Step past qualification or unchecked conversion (the latter can occur
7617 -- in cases of calls to 'Input).
7619 if Nkind_In (Func_Call,
7620 N_Qualified_Expression,
7621 N_Unchecked_Type_Conversion)
7623 Func_Call := Expression (Func_Call);
7626 -- If the call has already been processed to add build-in-place actuals
7627 -- then return. This should not normally occur in an allocator context,
7628 -- but we add the protection as a defensive measure.
7630 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7634 -- Mark the call as processed as a build-in-place call
7636 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7638 Loc := Sloc (Function_Call);
7640 if Is_Entity_Name (Name (Func_Call)) then
7641 Function_Id := Entity (Name (Func_Call));
7643 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7644 Function_Id := Etype (Name (Func_Call));
7647 raise Program_Error;
7650 Result_Subt := Available_View (Etype (Function_Id));
7652 -- Check whether return type includes tasks. This may not have been done
7653 -- previously, if the type was a limited view.
7655 if Has_Task (Result_Subt) then
7656 Build_Activation_Chain_Entity (Allocator);
7659 -- When the result subtype is constrained, the return object must be
7660 -- allocated on the caller side, and access to it is passed to the
7663 -- Here and in related routines, we must examine the full view of the
7664 -- type, because the view at the point of call may differ from that
7665 -- that in the function body, and the expansion mechanism depends on
7666 -- the characteristics of the full view.
7668 if Is_Constrained (Underlying_Type (Result_Subt)) then
7670 -- Replace the initialized allocator of form "new T'(Func (...))"
7671 -- with an uninitialized allocator of form "new T", where T is the
7672 -- result subtype of the called function. The call to the function
7673 -- is handled separately further below.
7676 Make_Allocator (Loc,
7677 Expression => New_Reference_To (Result_Subt, Loc));
7678 Set_No_Initialization (New_Allocator);
7680 -- Copy attributes to new allocator. Note that the new allocator
7681 -- logically comes from source if the original one did, so copy the
7682 -- relevant flag. This ensures proper treatment of the restriction
7683 -- No_Implicit_Heap_Allocations in this case.
7685 Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator));
7686 Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator));
7687 Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator));
7689 Rewrite (Allocator, New_Allocator);
7691 -- Create a new access object and initialize it to the result of the
7692 -- new uninitialized allocator. Note: we do not use Allocator as the
7693 -- Related_Node of Return_Obj_Access in call to Make_Temporary below
7694 -- as this would create a sort of infinite "recursion".
7696 Return_Obj_Access := Make_Temporary (Loc, 'R');
7697 Set_Etype (Return_Obj_Access, Acc_Type);
7699 Insert_Action (Allocator,
7700 Make_Object_Declaration (Loc,
7701 Defining_Identifier => Return_Obj_Access,
7702 Object_Definition => New_Reference_To (Acc_Type, Loc),
7703 Expression => Relocate_Node (Allocator)));
7705 -- When the function has a controlling result, an allocation-form
7706 -- parameter must be passed indicating that the caller is allocating
7707 -- the result object. This is needed because such a function can be
7708 -- called as a dispatching operation and must be treated similarly
7709 -- to functions with unconstrained result subtypes.
7711 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7712 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7714 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7715 (Func_Call, Function_Id, Acc_Type);
7717 Add_Task_Actuals_To_Build_In_Place_Call
7718 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
7720 -- Add an implicit actual to the function call that provides access
7721 -- to the allocated object. An unchecked conversion to the (specific)
7722 -- result subtype of the function is inserted to handle cases where
7723 -- the access type of the allocator has a class-wide designated type.
7725 Add_Access_Actual_To_Build_In_Place_Call
7728 Make_Unchecked_Type_Conversion (Loc,
7729 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
7731 Make_Explicit_Dereference (Loc,
7732 Prefix => New_Reference_To (Return_Obj_Access, Loc))));
7734 -- When the result subtype is unconstrained, the function itself must
7735 -- perform the allocation of the return object, so we pass parameters
7736 -- indicating that. We don't yet handle the case where the allocation
7737 -- must be done in a user-defined storage pool, which will require
7738 -- passing another actual or two to provide allocation/deallocation
7742 -- Case of a user-defined storage pool. Pass an allocation parameter
7743 -- indicating that the function should allocate its result in the
7744 -- pool, and pass the pool. Use 'Unrestricted_Access because the
7745 -- pool may not be aliased.
7747 if VM_Target = No_VM
7748 and then Present (Associated_Storage_Pool (Acc_Type))
7750 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7751 (Func_Call, Function_Id, Alloc_Form => User_Storage_Pool,
7753 Make_Attribute_Reference (Loc,
7756 (Associated_Storage_Pool (Acc_Type), Loc),
7757 Attribute_Name => Name_Unrestricted_Access));
7759 -- No user-defined pool; pass an allocation parameter indicating that
7760 -- the function should allocate its result on the heap.
7763 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7764 (Func_Call, Function_Id, Alloc_Form => Global_Heap);
7767 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7768 (Func_Call, Function_Id, Acc_Type);
7770 Add_Task_Actuals_To_Build_In_Place_Call
7771 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
7773 -- The caller does not provide the return object in this case, so we
7774 -- have to pass null for the object access actual.
7776 Add_Access_Actual_To_Build_In_Place_Call
7777 (Func_Call, Function_Id, Return_Object => Empty);
7780 -- If the build-in-place function call returns a controlled object,
7781 -- the finalization master will require a reference to routine
7782 -- Finalize_Address of the designated type. Setting this attribute
7783 -- is done in the same manner to expansion of allocators.
7785 if Needs_Finalization (Result_Subt) then
7787 -- Controlled types with supressed finalization do not need to
7788 -- associate the address of their Finalize_Address primitives with
7789 -- a master since they do not need a master to begin with.
7791 if Is_Library_Level_Entity (Acc_Type)
7792 and then Finalize_Storage_Only (Result_Subt)
7796 -- Do not generate the call to Set_Finalize_Address in Alfa mode
7797 -- because it is not necessary and results in unwanted expansion.
7798 -- This expansion is also not carried out in CodePeer mode because
7799 -- Finalize_Address is never built.
7802 and then not CodePeer_Mode
7804 Insert_Action (Allocator,
7805 Make_Set_Finalize_Address_Call (Loc,
7806 Typ => Etype (Function_Id),
7807 Ptr_Typ => Acc_Type));
7811 -- Finally, replace the allocator node with a reference to the result
7812 -- of the function call itself (which will effectively be an access
7813 -- to the object created by the allocator).
7815 Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call)));
7817 -- Ada 2005 (AI-251): If the type of the allocator is an interface then
7818 -- generate an implicit conversion to force displacement of the "this"
7821 if Is_Interface (Designated_Type (Acc_Type)) then
7822 Rewrite (Allocator, Convert_To (Acc_Type, Relocate_Node (Allocator)));
7825 Analyze_And_Resolve (Allocator, Acc_Type);
7826 end Make_Build_In_Place_Call_In_Allocator;
7828 ---------------------------------------------------
7829 -- Make_Build_In_Place_Call_In_Anonymous_Context --
7830 ---------------------------------------------------
7832 procedure Make_Build_In_Place_Call_In_Anonymous_Context
7833 (Function_Call : Node_Id)
7836 Func_Call : Node_Id := Function_Call;
7837 Function_Id : Entity_Id;
7838 Result_Subt : Entity_Id;
7839 Return_Obj_Id : Entity_Id;
7840 Return_Obj_Decl : Entity_Id;
7843 -- Step past qualification or unchecked conversion (the latter can occur
7844 -- in cases of calls to 'Input).
7846 if Nkind_In (Func_Call, N_Qualified_Expression,
7847 N_Unchecked_Type_Conversion)
7849 Func_Call := Expression (Func_Call);
7852 -- If the call has already been processed to add build-in-place actuals
7853 -- then return. One place this can occur is for calls to build-in-place
7854 -- functions that occur within a call to a protected operation, where
7855 -- due to rewriting and expansion of the protected call there can be
7856 -- more than one call to Expand_Actuals for the same set of actuals.
7858 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7862 -- Mark the call as processed as a build-in-place call
7864 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7866 Loc := Sloc (Function_Call);
7868 if Is_Entity_Name (Name (Func_Call)) then
7869 Function_Id := Entity (Name (Func_Call));
7871 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7872 Function_Id := Etype (Name (Func_Call));
7875 raise Program_Error;
7878 Result_Subt := Etype (Function_Id);
7880 -- If the build-in-place function returns a controlled object, then the
7881 -- object needs to be finalized immediately after the context. Since
7882 -- this case produces a transient scope, the servicing finalizer needs
7883 -- to name the returned object. Create a temporary which is initialized
7884 -- with the function call:
7886 -- Temp_Id : Func_Type := BIP_Func_Call;
7888 -- The initialization expression of the temporary will be rewritten by
7889 -- the expander using the appropriate mechanism in Make_Build_In_Place_
7890 -- Call_In_Object_Declaration.
7892 if Needs_Finalization (Result_Subt) then
7894 Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'R');
7895 Temp_Decl : Node_Id;
7898 -- Reset the guard on the function call since the following does
7899 -- not perform actual call expansion.
7901 Set_Is_Expanded_Build_In_Place_Call (Func_Call, False);
7904 Make_Object_Declaration (Loc,
7905 Defining_Identifier => Temp_Id,
7906 Object_Definition =>
7907 New_Reference_To (Result_Subt, Loc),
7909 New_Copy_Tree (Function_Call));
7911 Insert_Action (Function_Call, Temp_Decl);
7913 Rewrite (Function_Call, New_Reference_To (Temp_Id, Loc));
7914 Analyze (Function_Call);
7917 -- When the result subtype is constrained, an object of the subtype is
7918 -- declared and an access value designating it is passed as an actual.
7920 elsif Is_Constrained (Underlying_Type (Result_Subt)) then
7922 -- Create a temporary object to hold the function result
7924 Return_Obj_Id := Make_Temporary (Loc, 'R');
7925 Set_Etype (Return_Obj_Id, Result_Subt);
7928 Make_Object_Declaration (Loc,
7929 Defining_Identifier => Return_Obj_Id,
7930 Aliased_Present => True,
7931 Object_Definition => New_Reference_To (Result_Subt, Loc));
7933 Set_No_Initialization (Return_Obj_Decl);
7935 Insert_Action (Func_Call, Return_Obj_Decl);
7937 -- When the function has a controlling result, an allocation-form
7938 -- parameter must be passed indicating that the caller is allocating
7939 -- the result object. This is needed because such a function can be
7940 -- called as a dispatching operation and must be treated similarly
7941 -- to functions with unconstrained result subtypes.
7943 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7944 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7946 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7947 (Func_Call, Function_Id);
7949 Add_Task_Actuals_To_Build_In_Place_Call
7950 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
7952 -- Add an implicit actual to the function call that provides access
7953 -- to the caller's return object.
7955 Add_Access_Actual_To_Build_In_Place_Call
7956 (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc));
7958 -- When the result subtype is unconstrained, the function must allocate
7959 -- the return object in the secondary stack, so appropriate implicit
7960 -- parameters are added to the call to indicate that. A transient
7961 -- scope is established to ensure eventual cleanup of the result.
7964 -- Pass an allocation parameter indicating that the function should
7965 -- allocate its result on the secondary stack.
7967 Add_Unconstrained_Actuals_To_Build_In_Place_Call
7968 (Func_Call, Function_Id, Alloc_Form => Secondary_Stack);
7970 Add_Finalization_Master_Actual_To_Build_In_Place_Call
7971 (Func_Call, Function_Id);
7973 Add_Task_Actuals_To_Build_In_Place_Call
7974 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
7976 -- Pass a null value to the function since no return object is
7977 -- available on the caller side.
7979 Add_Access_Actual_To_Build_In_Place_Call
7980 (Func_Call, Function_Id, Empty);
7982 end Make_Build_In_Place_Call_In_Anonymous_Context;
7984 --------------------------------------------
7985 -- Make_Build_In_Place_Call_In_Assignment --
7986 --------------------------------------------
7988 procedure Make_Build_In_Place_Call_In_Assignment
7990 Function_Call : Node_Id)
7992 Lhs : constant Node_Id := Name (Assign);
7993 Func_Call : Node_Id := Function_Call;
7994 Func_Id : Entity_Id;
7998 Ptr_Typ : Entity_Id;
7999 Ptr_Typ_Decl : Node_Id;
8001 Result_Subt : Entity_Id;
8005 -- Step past qualification or unchecked conversion (the latter can occur
8006 -- in cases of calls to 'Input).
8008 if Nkind_In (Func_Call, N_Qualified_Expression,
8009 N_Unchecked_Type_Conversion)
8011 Func_Call := Expression (Func_Call);
8014 -- If the call has already been processed to add build-in-place actuals
8015 -- then return. This should not normally occur in an assignment context,
8016 -- but we add the protection as a defensive measure.
8018 if Is_Expanded_Build_In_Place_Call (Func_Call) then
8022 -- Mark the call as processed as a build-in-place call
8024 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
8026 Loc := Sloc (Function_Call);
8028 if Is_Entity_Name (Name (Func_Call)) then
8029 Func_Id := Entity (Name (Func_Call));
8031 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
8032 Func_Id := Etype (Name (Func_Call));
8035 raise Program_Error;
8038 Result_Subt := Etype (Func_Id);
8040 -- When the result subtype is unconstrained, an additional actual must
8041 -- be passed to indicate that the caller is providing the return object.
8042 -- This parameter must also be passed when the called function has a
8043 -- controlling result, because dispatching calls to the function needs
8044 -- to be treated effectively the same as calls to class-wide functions.
8046 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8047 (Func_Call, Func_Id, Alloc_Form => Caller_Allocation);
8049 Add_Finalization_Master_Actual_To_Build_In_Place_Call
8050 (Func_Call, Func_Id);
8052 Add_Task_Actuals_To_Build_In_Place_Call
8053 (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster));
8055 -- Add an implicit actual to the function call that provides access to
8056 -- the caller's return object.
8058 Add_Access_Actual_To_Build_In_Place_Call
8061 Make_Unchecked_Type_Conversion (Loc,
8062 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
8063 Expression => Relocate_Node (Lhs)));
8065 -- Create an access type designating the function's result subtype
8067 Ptr_Typ := Make_Temporary (Loc, 'A');
8070 Make_Full_Type_Declaration (Loc,
8071 Defining_Identifier => Ptr_Typ,
8073 Make_Access_To_Object_Definition (Loc,
8074 All_Present => True,
8075 Subtype_Indication =>
8076 New_Reference_To (Result_Subt, Loc)));
8077 Insert_After_And_Analyze (Assign, Ptr_Typ_Decl);
8079 -- Finally, create an access object initialized to a reference to the
8080 -- function call. We know this access value is non-null, so mark the
8081 -- entity accordingly to suppress junk access checks.
8083 New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call));
8085 Obj_Id := Make_Temporary (Loc, 'R', New_Expr);
8086 Set_Etype (Obj_Id, Ptr_Typ);
8087 Set_Is_Known_Non_Null (Obj_Id);
8090 Make_Object_Declaration (Loc,
8091 Defining_Identifier => Obj_Id,
8092 Object_Definition => New_Reference_To (Ptr_Typ, Loc),
8093 Expression => New_Expr);
8094 Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl);
8096 Rewrite (Assign, Make_Null_Statement (Loc));
8098 -- Retrieve the target of the assignment
8100 if Nkind (Lhs) = N_Selected_Component then
8101 Target := Selector_Name (Lhs);
8102 elsif Nkind (Lhs) = N_Type_Conversion then
8103 Target := Expression (Lhs);
8108 -- If we are assigning to a return object or this is an expression of
8109 -- an extension aggregate, the target should either be an identifier
8110 -- or a simple expression. All other cases imply a different scenario.
8112 if Nkind (Target) in N_Has_Entity then
8113 Target := Entity (Target);
8117 end Make_Build_In_Place_Call_In_Assignment;
8119 ----------------------------------------------------
8120 -- Make_Build_In_Place_Call_In_Object_Declaration --
8121 ----------------------------------------------------
8123 procedure Make_Build_In_Place_Call_In_Object_Declaration
8124 (Object_Decl : Node_Id;
8125 Function_Call : Node_Id)
8128 Obj_Def_Id : constant Entity_Id :=
8129 Defining_Identifier (Object_Decl);
8130 Enclosing_Func : constant Entity_Id :=
8131 Enclosing_Subprogram (Obj_Def_Id);
8132 Call_Deref : Node_Id;
8133 Caller_Object : Node_Id;
8135 Fmaster_Actual : Node_Id := Empty;
8136 Func_Call : Node_Id := Function_Call;
8137 Function_Id : Entity_Id;
8138 Pool_Actual : Node_Id;
8139 Ptr_Typ_Decl : Node_Id;
8140 Pass_Caller_Acc : Boolean := False;
8142 Ref_Type : Entity_Id;
8143 Result_Subt : Entity_Id;
8146 -- Step past qualification or unchecked conversion (the latter can occur
8147 -- in cases of calls to 'Input).
8149 if Nkind_In (Func_Call, N_Qualified_Expression,
8150 N_Unchecked_Type_Conversion)
8152 Func_Call := Expression (Func_Call);
8155 -- If the call has already been processed to add build-in-place actuals
8156 -- then return. This should not normally occur in an object declaration,
8157 -- but we add the protection as a defensive measure.
8159 if Is_Expanded_Build_In_Place_Call (Func_Call) then
8163 -- Mark the call as processed as a build-in-place call
8165 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
8167 Loc := Sloc (Function_Call);
8169 if Is_Entity_Name (Name (Func_Call)) then
8170 Function_Id := Entity (Name (Func_Call));
8172 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
8173 Function_Id := Etype (Name (Func_Call));
8176 raise Program_Error;
8179 Result_Subt := Etype (Function_Id);
8181 -- If the the object is a return object of an enclosing build-in-place
8182 -- function, then the implicit build-in-place parameters of the
8183 -- enclosing function are simply passed along to the called function.
8184 -- (Unfortunately, this won't cover the case of extension aggregates
8185 -- where the ancestor part is a build-in-place unconstrained function
8186 -- call that should be passed along the caller's parameters. Currently
8187 -- those get mishandled by reassigning the result of the call to the
8188 -- aggregate return object, when the call result should really be
8189 -- directly built in place in the aggregate and not in a temporary. ???)
8191 if Is_Return_Object (Defining_Identifier (Object_Decl)) then
8192 Pass_Caller_Acc := True;
8194 -- When the enclosing function has a BIP_Alloc_Form formal then we
8195 -- pass it along to the callee (such as when the enclosing function
8196 -- has an unconstrained or tagged result type).
8198 if Needs_BIP_Alloc_Form (Enclosing_Func) then
8199 if VM_Target = No_VM and then
8200 RTE_Available (RE_Root_Storage_Pool_Ptr)
8203 New_Reference_To (Build_In_Place_Formal
8204 (Enclosing_Func, BIP_Storage_Pool), Loc);
8206 -- The build-in-place pool formal is not built on .NET/JVM
8209 Pool_Actual := Empty;
8212 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8217 (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form),
8219 Pool_Actual => Pool_Actual);
8221 -- Otherwise, if enclosing function has a constrained result subtype,
8222 -- then caller allocation will be used.
8225 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8226 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
8229 if Needs_BIP_Finalization_Master (Enclosing_Func) then
8232 (Build_In_Place_Formal
8233 (Enclosing_Func, BIP_Finalization_Master), Loc);
8236 -- Retrieve the BIPacc formal from the enclosing function and convert
8237 -- it to the access type of the callee's BIP_Object_Access formal.
8240 Make_Unchecked_Type_Conversion (Loc,
8244 (Build_In_Place_Formal (Function_Id, BIP_Object_Access)),
8248 (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access),
8251 -- In the constrained case, add an implicit actual to the function call
8252 -- that provides access to the declared object. An unchecked conversion
8253 -- to the (specific) result type of the function is inserted to handle
8254 -- the case where the object is declared with a class-wide type.
8256 elsif Is_Constrained (Underlying_Type (Result_Subt)) then
8258 Make_Unchecked_Type_Conversion (Loc,
8259 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
8260 Expression => New_Reference_To (Obj_Def_Id, Loc));
8262 -- When the function has a controlling result, an allocation-form
8263 -- parameter must be passed indicating that the caller is allocating
8264 -- the result object. This is needed because such a function can be
8265 -- called as a dispatching operation and must be treated similarly
8266 -- to functions with unconstrained result subtypes.
8268 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8269 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
8271 -- In other unconstrained cases, pass an indication to do the allocation
8272 -- on the secondary stack and set Caller_Object to Empty so that a null
8273 -- value will be passed for the caller's object address. A transient
8274 -- scope is established to ensure eventual cleanup of the result.
8277 Add_Unconstrained_Actuals_To_Build_In_Place_Call
8278 (Func_Call, Function_Id, Alloc_Form => Secondary_Stack);
8279 Caller_Object := Empty;
8281 Establish_Transient_Scope (Object_Decl, Sec_Stack => True);
8284 -- Pass along any finalization master actual, which is needed in the
8285 -- case where the called function initializes a return object of an
8286 -- enclosing build-in-place function.
8288 Add_Finalization_Master_Actual_To_Build_In_Place_Call
8289 (Func_Call => Func_Call,
8290 Func_Id => Function_Id,
8291 Master_Exp => Fmaster_Actual);
8293 if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement
8294 and then Has_Task (Result_Subt)
8296 -- Here we're passing along the master that was passed in to this
8299 Add_Task_Actuals_To_Build_In_Place_Call
8300 (Func_Call, Function_Id,
8302 New_Reference_To (Build_In_Place_Formal
8303 (Enclosing_Func, BIP_Task_Master), Loc));
8306 Add_Task_Actuals_To_Build_In_Place_Call
8307 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
8310 Add_Access_Actual_To_Build_In_Place_Call
8311 (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc);
8313 -- Create an access type designating the function's result subtype. We
8314 -- use the type of the original expression because it may be a call to
8315 -- an inherited operation, which the expansion has replaced with the
8316 -- parent operation that yields the parent type.
8318 Ref_Type := Make_Temporary (Loc, 'A');
8321 Make_Full_Type_Declaration (Loc,
8322 Defining_Identifier => Ref_Type,
8324 Make_Access_To_Object_Definition (Loc,
8325 All_Present => True,
8326 Subtype_Indication =>
8327 New_Reference_To (Etype (Function_Call), Loc)));
8329 -- The access type and its accompanying object must be inserted after
8330 -- the object declaration in the constrained case, so that the function
8331 -- call can be passed access to the object. In the unconstrained case,
8332 -- or if the object declaration is for a return object, the access type
8333 -- and object must be inserted before the object, since the object
8334 -- declaration is rewritten to be a renaming of a dereference of the
8337 if Is_Constrained (Underlying_Type (Result_Subt))
8338 and then not Is_Return_Object (Defining_Identifier (Object_Decl))
8340 Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl);
8342 Insert_Action (Object_Decl, Ptr_Typ_Decl);
8345 -- Finally, create an access object initialized to a reference to the
8346 -- function call. We know this access value cannot be null, so mark the
8347 -- entity accordingly to suppress the access check.
8349 New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call));
8351 Def_Id := Make_Temporary (Loc, 'R', New_Expr);
8352 Set_Etype (Def_Id, Ref_Type);
8353 Set_Is_Known_Non_Null (Def_Id);
8355 Insert_After_And_Analyze (Ptr_Typ_Decl,
8356 Make_Object_Declaration (Loc,
8357 Defining_Identifier => Def_Id,
8358 Object_Definition => New_Reference_To (Ref_Type, Loc),
8359 Expression => New_Expr));
8361 -- If the result subtype of the called function is constrained and
8362 -- is not itself the return expression of an enclosing BIP function,
8363 -- then mark the object as having no initialization.
8365 if Is_Constrained (Underlying_Type (Result_Subt))
8366 and then not Is_Return_Object (Defining_Identifier (Object_Decl))
8368 Set_Expression (Object_Decl, Empty);
8369 Set_No_Initialization (Object_Decl);
8371 -- In case of an unconstrained result subtype, or if the call is the
8372 -- return expression of an enclosing BIP function, rewrite the object
8373 -- declaration as an object renaming where the renamed object is a
8374 -- dereference of <function_Call>'reference:
8376 -- Obj : Subt renames <function_call>'Ref.all;
8380 Make_Explicit_Dereference (Loc,
8381 Prefix => New_Reference_To (Def_Id, Loc));
8383 Loc := Sloc (Object_Decl);
8384 Rewrite (Object_Decl,
8385 Make_Object_Renaming_Declaration (Loc,
8386 Defining_Identifier => Make_Temporary (Loc, 'D'),
8387 Access_Definition => Empty,
8388 Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc),
8389 Name => Call_Deref));
8391 Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref);
8393 Analyze (Object_Decl);
8395 -- Replace the internal identifier of the renaming declaration's
8396 -- entity with identifier of the original object entity. We also have
8397 -- to exchange the entities containing their defining identifiers to
8398 -- ensure the correct replacement of the object declaration by the
8399 -- object renaming declaration to avoid homograph conflicts (since
8400 -- the object declaration's defining identifier was already entered
8401 -- in current scope). The Next_Entity links of the two entities also
8402 -- have to be swapped since the entities are part of the return
8403 -- scope's entity list and the list structure would otherwise be
8404 -- corrupted. Finally, the homonym chain must be preserved as well.
8407 Renaming_Def_Id : constant Entity_Id :=
8408 Defining_Identifier (Object_Decl);
8409 Next_Entity_Temp : constant Entity_Id :=
8410 Next_Entity (Renaming_Def_Id);
8412 Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id));
8414 -- Swap next entity links in preparation for exchanging entities
8416 Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id));
8417 Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp);
8418 Set_Homonym (Renaming_Def_Id, Homonym (Obj_Def_Id));
8420 Exchange_Entities (Renaming_Def_Id, Obj_Def_Id);
8422 -- Preserve source indication of original declaration, so that
8423 -- xref information is properly generated for the right entity.
8425 Preserve_Comes_From_Source
8426 (Object_Decl, Original_Node (Object_Decl));
8428 Preserve_Comes_From_Source
8429 (Obj_Def_Id, Original_Node (Object_Decl));
8431 Set_Comes_From_Source (Renaming_Def_Id, False);
8435 -- If the object entity has a class-wide Etype, then we need to change
8436 -- it to the result subtype of the function call, because otherwise the
8437 -- object will be class-wide without an explicit initialization and
8438 -- won't be allocated properly by the back end. It seems unclean to make
8439 -- such a revision to the type at this point, and we should try to
8440 -- improve this treatment when build-in-place functions with class-wide
8441 -- results are implemented. ???
8443 if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then
8444 Set_Etype (Defining_Identifier (Object_Decl), Result_Subt);
8446 end Make_Build_In_Place_Call_In_Object_Declaration;
8448 -----------------------------------
8449 -- Needs_BIP_Finalization_Master --
8450 -----------------------------------
8452 function Needs_BIP_Finalization_Master
8453 (Func_Id : Entity_Id) return Boolean
8455 pragma Assert (Is_Build_In_Place_Function (Func_Id));
8456 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8459 not Restriction_Active (No_Finalization)
8460 and then Needs_Finalization (Func_Typ);
8461 end Needs_BIP_Finalization_Master;
8463 --------------------------
8464 -- Needs_BIP_Alloc_Form --
8465 --------------------------
8467 function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean is
8468 pragma Assert (Is_Build_In_Place_Function (Func_Id));
8469 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8471 return not Is_Constrained (Func_Typ) or else Is_Tagged_Type (Func_Typ);
8472 end Needs_BIP_Alloc_Form;
8474 --------------------------------------
8475 -- Needs_Result_Accessibility_Level --
8476 --------------------------------------
8478 function Needs_Result_Accessibility_Level
8479 (Func_Id : Entity_Id) return Boolean
8481 Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
8483 function Has_Unconstrained_Access_Discriminant_Component
8484 (Comp_Typ : Entity_Id) return Boolean;
8485 -- Returns True if any component of the type has an unconstrained access
8488 -----------------------------------------------------
8489 -- Has_Unconstrained_Access_Discriminant_Component --
8490 -----------------------------------------------------
8492 function Has_Unconstrained_Access_Discriminant_Component
8493 (Comp_Typ : Entity_Id) return Boolean
8496 if not Is_Limited_Type (Comp_Typ) then
8499 -- Only limited types can have access discriminants with
8502 elsif Has_Unconstrained_Access_Discriminants (Comp_Typ) then
8505 elsif Is_Array_Type (Comp_Typ) then
8506 return Has_Unconstrained_Access_Discriminant_Component
8507 (Underlying_Type (Component_Type (Comp_Typ)));
8509 elsif Is_Record_Type (Comp_Typ) then
8514 Comp := First_Component (Comp_Typ);
8515 while Present (Comp) loop
8516 if Has_Unconstrained_Access_Discriminant_Component
8517 (Underlying_Type (Etype (Comp)))
8522 Next_Component (Comp);
8528 end Has_Unconstrained_Access_Discriminant_Component;
8530 Feature_Disabled : constant Boolean := True;
8533 -- Start of processing for Needs_Result_Accessibility_Level
8536 -- False if completion unavailable (how does this happen???)
8538 if not Present (Func_Typ) then
8541 elsif Feature_Disabled then
8544 -- False if not a function, also handle enum-lit renames case
8546 elsif Func_Typ = Standard_Void_Type
8547 or else Is_Scalar_Type (Func_Typ)
8551 -- Handle a corner case, a cross-dialect subp renaming. For example,
8552 -- an Ada 2012 renaming of an Ada 2005 subprogram. This can occur when
8553 -- an Ada 2005 (or earlier) unit references predefined run-time units.
8555 elsif Present (Alias (Func_Id)) then
8557 -- Unimplemented: a cross-dialect subp renaming which does not set
8558 -- the Alias attribute (e.g., a rename of a dereference of an access
8559 -- to subprogram value). ???
8561 return Present (Extra_Accessibility_Of_Result (Alias (Func_Id)));
8563 -- Remaining cases require Ada 2012 mode
8565 elsif Ada_Version < Ada_2012 then
8568 elsif Ekind (Func_Typ) = E_Anonymous_Access_Type
8569 or else Is_Tagged_Type (Func_Typ)
8571 -- In the case of, say, a null tagged record result type, the need
8572 -- for this extra parameter might not be obvious. This function
8573 -- returns True for all tagged types for compatibility reasons.
8574 -- A function with, say, a tagged null controlling result type might
8575 -- be overridden by a primitive of an extension having an access
8576 -- discriminant and the overrider and overridden must have compatible
8577 -- calling conventions (including implicitly declared parameters).
8578 -- Similarly, values of one access-to-subprogram type might designate
8579 -- both a primitive subprogram of a given type and a function
8580 -- which is, for example, not a primitive subprogram of any type.
8581 -- Again, this requires calling convention compatibility.
8582 -- It might be possible to solve these issues by introducing
8583 -- wrappers, but that is not the approach that was chosen.
8587 elsif Has_Unconstrained_Access_Discriminants (Func_Typ) then
8590 elsif Has_Unconstrained_Access_Discriminant_Component (Func_Typ) then
8593 -- False for all other cases
8598 end Needs_Result_Accessibility_Level;