[multiple changes]
[gcc.git] / gcc / ada / exp_ch6.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- E X P _ C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
10 -- --
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. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
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_Atag; use Exp_Atag;
33 with Exp_Ch2; use Exp_Ch2;
34 with Exp_Ch3; use Exp_Ch3;
35 with Exp_Ch7; use Exp_Ch7;
36 with Exp_Ch9; use Exp_Ch9;
37 with Exp_Dbug; use Exp_Dbug;
38 with Exp_Disp; use Exp_Disp;
39 with Exp_Dist; use Exp_Dist;
40 with Exp_Intr; use Exp_Intr;
41 with Exp_Pakd; use Exp_Pakd;
42 with Exp_Tss; use Exp_Tss;
43 with Exp_Util; use Exp_Util;
44 with Exp_VFpt; use Exp_VFpt;
45 with Fname; use Fname;
46 with Freeze; use Freeze;
47 with Inline; use Inline;
48 with Lib; use Lib;
49 with Namet; use Namet;
50 with Nlists; use Nlists;
51 with Nmake; use Nmake;
52 with Opt; use Opt;
53 with Restrict; use Restrict;
54 with Rident; use Rident;
55 with Rtsfind; use Rtsfind;
56 with Sem; use Sem;
57 with Sem_Aux; use Sem_Aux;
58 with Sem_Ch6; use Sem_Ch6;
59 with Sem_Ch8; use Sem_Ch8;
60 with Sem_Ch12; use Sem_Ch12;
61 with Sem_Ch13; use Sem_Ch13;
62 with Sem_Eval; use Sem_Eval;
63 with Sem_Disp; use Sem_Disp;
64 with Sem_Dist; use Sem_Dist;
65 with Sem_Mech; use Sem_Mech;
66 with Sem_Res; use Sem_Res;
67 with Sem_SCIL; use Sem_SCIL;
68 with Sem_Util; use Sem_Util;
69 with Sinfo; use Sinfo;
70 with Snames; use Snames;
71 with Stand; use Stand;
72 with Targparm; use Targparm;
73 with Tbuild; use Tbuild;
74 with Uintp; use Uintp;
75 with Validsw; use Validsw;
76
77 package body Exp_Ch6 is
78
79 -----------------------
80 -- Local Subprograms --
81 -----------------------
82
83 procedure Add_Access_Actual_To_Build_In_Place_Call
84 (Function_Call : Node_Id;
85 Function_Id : Entity_Id;
86 Return_Object : Node_Id;
87 Is_Access : Boolean := False);
88 -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the
89 -- object name given by Return_Object and add the attribute to the end of
90 -- the actual parameter list associated with the build-in-place function
91 -- call denoted by Function_Call. However, if Is_Access is True, then
92 -- Return_Object is already an access expression, in which case it's passed
93 -- along directly to the build-in-place function. Finally, if Return_Object
94 -- is empty, then pass a null literal as the actual.
95
96 procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call
97 (Function_Call : Node_Id;
98 Function_Id : Entity_Id;
99 Alloc_Form : BIP_Allocation_Form := Unspecified;
100 Alloc_Form_Exp : Node_Id := Empty);
101 -- Ada 2005 (AI-318-02): Add an actual indicating the form of allocation,
102 -- if any, to be done by a build-in-place function. If Alloc_Form_Exp is
103 -- present, then use it, otherwise pass a literal corresponding to the
104 -- Alloc_Form parameter (which must not be Unspecified in that case).
105
106 procedure Add_Extra_Actual_To_Call
107 (Subprogram_Call : Node_Id;
108 Extra_Formal : Entity_Id;
109 Extra_Actual : Node_Id);
110 -- Adds Extra_Actual as a named parameter association for the formal
111 -- Extra_Formal in Subprogram_Call.
112
113 procedure Add_Final_List_Actual_To_Build_In_Place_Call
114 (Function_Call : Node_Id;
115 Function_Id : Entity_Id;
116 Acc_Type : Entity_Id;
117 Sel_Comp : Node_Id := Empty);
118 -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type has
119 -- controlled parts, add an actual parameter that is a pointer to
120 -- appropriate finalization list. The finalization list is that of the
121 -- current scope, except for "new Acc'(F(...))" in which case it's the
122 -- finalization list of the access type returned by the allocator. Acc_Type
123 -- is that type in the allocator case; Empty otherwise. If Sel_Comp is
124 -- not Empty, then it denotes a selected component and the finalization
125 -- list is obtained from the _controller list of the prefix object.
126
127 procedure Add_Task_Actuals_To_Build_In_Place_Call
128 (Function_Call : Node_Id;
129 Function_Id : Entity_Id;
130 Master_Actual : Node_Id);
131 -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type
132 -- contains tasks, add two actual parameters: the master, and a pointer to
133 -- the caller's activation chain. Master_Actual is the actual parameter
134 -- expression to pass for the master. In most cases, this is the current
135 -- master (_master). The two exceptions are: If the function call is the
136 -- initialization expression for an allocator, we pass the master of the
137 -- access type. If the function call is the initialization expression for a
138 -- return object, we pass along the master passed in by the caller. The
139 -- activation chain to pass is always the local one. Note: Master_Actual
140 -- can be Empty, but only if there are no tasks.
141
142 procedure Check_Overriding_Operation (Subp : Entity_Id);
143 -- Subp is a dispatching operation. Check whether it may override an
144 -- inherited private operation, in which case its DT entry is that of
145 -- the hidden operation, not the one it may have received earlier.
146 -- This must be done before emitting the code to set the corresponding
147 -- DT to the address of the subprogram. The actual placement of Subp in
148 -- the proper place in the list of primitive operations is done in
149 -- Declare_Inherited_Private_Subprograms, which also has to deal with
150 -- implicit operations. This duplication is unavoidable for now???
151
152 procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id);
153 -- This procedure is called only if the subprogram body N, whose spec
154 -- has the given entity Spec, contains a parameterless recursive call.
155 -- It attempts to generate runtime code to detect if this a case of
156 -- infinite recursion.
157 --
158 -- The body is scanned to determine dependencies. If the only external
159 -- dependencies are on a small set of scalar variables, then the values
160 -- of these variables are captured on entry to the subprogram, and if
161 -- the values are not changed for the call, we know immediately that
162 -- we have an infinite recursion.
163
164 procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id);
165 -- For each actual of an in-out or out parameter which is a numeric
166 -- (view) conversion of the form T (A), where A denotes a variable,
167 -- we insert the declaration:
168 --
169 -- Temp : T[ := T (A)];
170 --
171 -- prior to the call. Then we replace the actual with a reference to Temp,
172 -- and append the assignment:
173 --
174 -- A := TypeA (Temp);
175 --
176 -- after the call. Here TypeA is the actual type of variable A. For out
177 -- parameters, the initial declaration has no expression. If A is not an
178 -- entity name, we generate instead:
179 --
180 -- Var : TypeA renames A;
181 -- Temp : T := Var; -- omitting expression for out parameter.
182 -- ...
183 -- Var := TypeA (Temp);
184 --
185 -- For other in-out parameters, we emit the required constraint checks
186 -- before and/or after the call.
187 --
188 -- For all parameter modes, actuals that denote components and slices of
189 -- packed arrays are expanded into suitable temporaries.
190 --
191 -- For non-scalar objects that are possibly unaligned, add call by copy
192 -- code (copy in for IN and IN OUT, copy out for OUT and IN OUT).
193
194 procedure Expand_Inlined_Call
195 (N : Node_Id;
196 Subp : Entity_Id;
197 Orig_Subp : Entity_Id);
198 -- If called subprogram can be inlined by the front-end, retrieve the
199 -- analyzed body, replace formals with actuals and expand call in place.
200 -- Generate thunks for actuals that are expressions, and insert the
201 -- corresponding constant declarations before the call. If the original
202 -- call is to a derived operation, the return type is the one of the
203 -- derived operation, but the body is that of the original, so return
204 -- expressions in the body must be converted to the desired type (which
205 -- is simply not noted in the tree without inline expansion).
206
207 procedure Expand_Non_Function_Return (N : Node_Id);
208 -- Called by Expand_N_Simple_Return_Statement in case we're returning from
209 -- a procedure body, entry body, accept statement, or extended return
210 -- statement. Note that all non-function returns are simple return
211 -- statements.
212
213 function Expand_Protected_Object_Reference
214 (N : Node_Id;
215 Scop : Entity_Id) return Node_Id;
216
217 procedure Expand_Protected_Subprogram_Call
218 (N : Node_Id;
219 Subp : Entity_Id;
220 Scop : Entity_Id);
221 -- A call to a protected subprogram within the protected object may appear
222 -- as a regular call. The list of actuals must be expanded to contain a
223 -- reference to the object itself, and the call becomes a call to the
224 -- corresponding protected subprogram.
225
226 function Is_Null_Procedure (Subp : Entity_Id) return Boolean;
227 -- Predicate to recognize stubbed procedures and null procedures, which
228 -- can be inlined unconditionally in all cases.
229
230 procedure Expand_Simple_Function_Return (N : Node_Id);
231 -- Expand simple return from function. In the case where we are returning
232 -- from a function body this is called by Expand_N_Simple_Return_Statement.
233
234 ----------------------------------------------
235 -- Add_Access_Actual_To_Build_In_Place_Call --
236 ----------------------------------------------
237
238 procedure Add_Access_Actual_To_Build_In_Place_Call
239 (Function_Call : Node_Id;
240 Function_Id : Entity_Id;
241 Return_Object : Node_Id;
242 Is_Access : Boolean := False)
243 is
244 Loc : constant Source_Ptr := Sloc (Function_Call);
245 Obj_Address : Node_Id;
246 Obj_Acc_Formal : Entity_Id;
247
248 begin
249 -- Locate the implicit access parameter in the called function
250
251 Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access);
252
253 -- If no return object is provided, then pass null
254
255 if not Present (Return_Object) then
256 Obj_Address := Make_Null (Loc);
257 Set_Parent (Obj_Address, Function_Call);
258
259 -- If Return_Object is already an expression of an access type, then use
260 -- it directly, since it must be an access value denoting the return
261 -- object, and couldn't possibly be the return object itself.
262
263 elsif Is_Access then
264 Obj_Address := Return_Object;
265 Set_Parent (Obj_Address, Function_Call);
266
267 -- Apply Unrestricted_Access to caller's return object
268
269 else
270 Obj_Address :=
271 Make_Attribute_Reference (Loc,
272 Prefix => Return_Object,
273 Attribute_Name => Name_Unrestricted_Access);
274
275 Set_Parent (Return_Object, Obj_Address);
276 Set_Parent (Obj_Address, Function_Call);
277 end if;
278
279 Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal));
280
281 -- Build the parameter association for the new actual and add it to the
282 -- end of the function's actuals.
283
284 Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address);
285 end Add_Access_Actual_To_Build_In_Place_Call;
286
287 --------------------------------------------------
288 -- Add_Alloc_Form_Actual_To_Build_In_Place_Call --
289 --------------------------------------------------
290
291 procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call
292 (Function_Call : Node_Id;
293 Function_Id : Entity_Id;
294 Alloc_Form : BIP_Allocation_Form := Unspecified;
295 Alloc_Form_Exp : Node_Id := Empty)
296 is
297 Loc : constant Source_Ptr := Sloc (Function_Call);
298 Alloc_Form_Actual : Node_Id;
299 Alloc_Form_Formal : Node_Id;
300
301 begin
302 -- The allocation form generally doesn't need to be passed in the case
303 -- of a constrained result subtype, since normally the caller performs
304 -- the allocation in that case. However this formal is still needed in
305 -- the case where the function has a tagged result, because generally
306 -- such functions can be called in a dispatching context and such calls
307 -- must be handled like calls to class-wide functions.
308
309 if Is_Constrained (Underlying_Type (Etype (Function_Id)))
310 and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id)))
311 then
312 return;
313 end if;
314
315 -- Locate the implicit allocation form parameter in the called function.
316 -- Maybe it would be better for each implicit formal of a build-in-place
317 -- function to have a flag or a Uint attribute to identify it. ???
318
319 Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form);
320
321 if Present (Alloc_Form_Exp) then
322 pragma Assert (Alloc_Form = Unspecified);
323
324 Alloc_Form_Actual := Alloc_Form_Exp;
325
326 else
327 pragma Assert (Alloc_Form /= Unspecified);
328
329 Alloc_Form_Actual :=
330 Make_Integer_Literal (Loc,
331 Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form)));
332 end if;
333
334 Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal));
335
336 -- Build the parameter association for the new actual and add it to the
337 -- end of the function's actuals.
338
339 Add_Extra_Actual_To_Call
340 (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual);
341 end Add_Alloc_Form_Actual_To_Build_In_Place_Call;
342
343 ------------------------------
344 -- Add_Extra_Actual_To_Call --
345 ------------------------------
346
347 procedure Add_Extra_Actual_To_Call
348 (Subprogram_Call : Node_Id;
349 Extra_Formal : Entity_Id;
350 Extra_Actual : Node_Id)
351 is
352 Loc : constant Source_Ptr := Sloc (Subprogram_Call);
353 Param_Assoc : Node_Id;
354
355 begin
356 Param_Assoc :=
357 Make_Parameter_Association (Loc,
358 Selector_Name => New_Occurrence_Of (Extra_Formal, Loc),
359 Explicit_Actual_Parameter => Extra_Actual);
360
361 Set_Parent (Param_Assoc, Subprogram_Call);
362 Set_Parent (Extra_Actual, Param_Assoc);
363
364 if Present (Parameter_Associations (Subprogram_Call)) then
365 if Nkind (Last (Parameter_Associations (Subprogram_Call))) =
366 N_Parameter_Association
367 then
368
369 -- Find last named actual, and append
370
371 declare
372 L : Node_Id;
373 begin
374 L := First_Actual (Subprogram_Call);
375 while Present (L) loop
376 if No (Next_Actual (L)) then
377 Set_Next_Named_Actual (Parent (L), Extra_Actual);
378 exit;
379 end if;
380 Next_Actual (L);
381 end loop;
382 end;
383
384 else
385 Set_First_Named_Actual (Subprogram_Call, Extra_Actual);
386 end if;
387
388 Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call));
389
390 else
391 Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc));
392 Set_First_Named_Actual (Subprogram_Call, Extra_Actual);
393 end if;
394 end Add_Extra_Actual_To_Call;
395
396 --------------------------------------------------
397 -- Add_Final_List_Actual_To_Build_In_Place_Call --
398 --------------------------------------------------
399
400 procedure Add_Final_List_Actual_To_Build_In_Place_Call
401 (Function_Call : Node_Id;
402 Function_Id : Entity_Id;
403 Acc_Type : Entity_Id;
404 Sel_Comp : Node_Id := Empty)
405 is
406 Loc : constant Source_Ptr := Sloc (Function_Call);
407 Final_List : Node_Id;
408 Final_List_Actual : Node_Id;
409 Final_List_Formal : Node_Id;
410 Is_Ctrl_Result : constant Boolean :=
411 Needs_Finalization
412 (Underlying_Type (Etype (Function_Id)));
413
414 begin
415 -- No such extra parameter is needed if there are no controlled parts.
416 -- The test for Needs_Finalization accounts for class-wide results
417 -- (which potentially have controlled parts, even if the root type
418 -- doesn't), and the test for a tagged result type is needed because
419 -- calls to such a function can in general occur in dispatching
420 -- contexts, which must be treated the same as a call to class-wide
421 -- functions. Both of these situations require that a finalization list
422 -- be passed.
423
424 if not Needs_BIP_Final_List (Function_Id) then
425 return;
426 end if;
427
428 -- Locate implicit finalization list parameter in the called function
429
430 Final_List_Formal := Build_In_Place_Formal (Function_Id, BIP_Final_List);
431
432 -- Create the actual which is a pointer to the appropriate finalization
433 -- list. Acc_Type is present if and only if this call is the
434 -- initialization of an allocator. Use the Current_Scope or the
435 -- Acc_Type as appropriate.
436
437 if Present (Acc_Type)
438 and then (Ekind (Acc_Type) = E_Anonymous_Access_Type
439 or else
440 Present (Associated_Final_Chain (Base_Type (Acc_Type))))
441 then
442 Final_List := Find_Final_List (Acc_Type);
443
444 -- If Sel_Comp is present and the function result is controlled, then
445 -- the finalization list will be obtained from the _controller list of
446 -- the selected component's prefix object.
447
448 elsif Present (Sel_Comp) and then Is_Ctrl_Result then
449 Final_List := Find_Final_List (Current_Scope, Sel_Comp);
450
451 else
452 Final_List := Find_Final_List (Current_Scope);
453 end if;
454
455 Final_List_Actual :=
456 Make_Attribute_Reference (Loc,
457 Prefix => Final_List,
458 Attribute_Name => Name_Unrestricted_Access);
459
460 Analyze_And_Resolve (Final_List_Actual, Etype (Final_List_Formal));
461
462 -- Build the parameter association for the new actual and add it to the
463 -- end of the function's actuals.
464
465 Add_Extra_Actual_To_Call
466 (Function_Call, Final_List_Formal, Final_List_Actual);
467 end Add_Final_List_Actual_To_Build_In_Place_Call;
468
469 ---------------------------------------------
470 -- Add_Task_Actuals_To_Build_In_Place_Call --
471 ---------------------------------------------
472
473 procedure Add_Task_Actuals_To_Build_In_Place_Call
474 (Function_Call : Node_Id;
475 Function_Id : Entity_Id;
476 Master_Actual : Node_Id)
477 is
478 Loc : constant Source_Ptr := Sloc (Function_Call);
479 Actual : Node_Id := Master_Actual;
480
481 begin
482 -- No such extra parameters are needed if there are no tasks
483
484 if not Has_Task (Etype (Function_Id)) then
485 return;
486 end if;
487
488 -- Use a dummy _master actual in case of No_Task_Hierarchy
489
490 if Restriction_Active (No_Task_Hierarchy) then
491 Actual := New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc);
492 end if;
493
494 -- The master
495
496 declare
497 Master_Formal : Node_Id;
498 begin
499 -- Locate implicit master parameter in the called function
500
501 Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Master);
502
503 Analyze_And_Resolve (Actual, Etype (Master_Formal));
504
505 -- Build the parameter association for the new actual and add it to
506 -- the end of the function's actuals.
507
508 Add_Extra_Actual_To_Call
509 (Function_Call, Master_Formal, Actual);
510 end;
511
512 -- The activation chain
513
514 declare
515 Activation_Chain_Actual : Node_Id;
516 Activation_Chain_Formal : Node_Id;
517
518 begin
519 -- Locate implicit activation chain parameter in the called function
520
521 Activation_Chain_Formal := Build_In_Place_Formal
522 (Function_Id, BIP_Activation_Chain);
523
524 -- Create the actual which is a pointer to the current activation
525 -- chain
526
527 Activation_Chain_Actual :=
528 Make_Attribute_Reference (Loc,
529 Prefix => Make_Identifier (Loc, Name_uChain),
530 Attribute_Name => Name_Unrestricted_Access);
531
532 Analyze_And_Resolve
533 (Activation_Chain_Actual, Etype (Activation_Chain_Formal));
534
535 -- Build the parameter association for the new actual and add it to
536 -- the end of the function's actuals.
537
538 Add_Extra_Actual_To_Call
539 (Function_Call, Activation_Chain_Formal, Activation_Chain_Actual);
540 end;
541 end Add_Task_Actuals_To_Build_In_Place_Call;
542
543 -----------------------
544 -- BIP_Formal_Suffix --
545 -----------------------
546
547 function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is
548 begin
549 case Kind is
550 when BIP_Alloc_Form =>
551 return "BIPalloc";
552 when BIP_Final_List =>
553 return "BIPfinallist";
554 when BIP_Master =>
555 return "BIPmaster";
556 when BIP_Activation_Chain =>
557 return "BIPactivationchain";
558 when BIP_Object_Access =>
559 return "BIPaccess";
560 end case;
561 end BIP_Formal_Suffix;
562
563 ---------------------------
564 -- Build_In_Place_Formal --
565 ---------------------------
566
567 function Build_In_Place_Formal
568 (Func : Entity_Id;
569 Kind : BIP_Formal_Kind) return Entity_Id
570 is
571 Extra_Formal : Entity_Id := Extra_Formals (Func);
572
573 begin
574 -- Maybe it would be better for each implicit formal of a build-in-place
575 -- function to have a flag or a Uint attribute to identify it. ???
576
577 loop
578 pragma Assert (Present (Extra_Formal));
579 exit when
580 Chars (Extra_Formal) =
581 New_External_Name (Chars (Func), BIP_Formal_Suffix (Kind));
582 Next_Formal_With_Extras (Extra_Formal);
583 end loop;
584
585 return Extra_Formal;
586 end Build_In_Place_Formal;
587
588 --------------------------------
589 -- Check_Overriding_Operation --
590 --------------------------------
591
592 procedure Check_Overriding_Operation (Subp : Entity_Id) is
593 Typ : constant Entity_Id := Find_Dispatching_Type (Subp);
594 Op_List : constant Elist_Id := Primitive_Operations (Typ);
595 Op_Elmt : Elmt_Id;
596 Prim_Op : Entity_Id;
597 Par_Op : Entity_Id;
598
599 begin
600 if Is_Derived_Type (Typ)
601 and then not Is_Private_Type (Typ)
602 and then In_Open_Scopes (Scope (Etype (Typ)))
603 and then Typ = Base_Type (Typ)
604 then
605 -- Subp overrides an inherited private operation if there is an
606 -- inherited operation with a different name than Subp (see
607 -- Derive_Subprogram) whose Alias is a hidden subprogram with the
608 -- same name as Subp.
609
610 Op_Elmt := First_Elmt (Op_List);
611 while Present (Op_Elmt) loop
612 Prim_Op := Node (Op_Elmt);
613 Par_Op := Alias (Prim_Op);
614
615 if Present (Par_Op)
616 and then not Comes_From_Source (Prim_Op)
617 and then Chars (Prim_Op) /= Chars (Par_Op)
618 and then Chars (Par_Op) = Chars (Subp)
619 and then Is_Hidden (Par_Op)
620 and then Type_Conformant (Prim_Op, Subp)
621 then
622 Set_DT_Position (Subp, DT_Position (Prim_Op));
623 end if;
624
625 Next_Elmt (Op_Elmt);
626 end loop;
627 end if;
628 end Check_Overriding_Operation;
629
630 -------------------------------
631 -- Detect_Infinite_Recursion --
632 -------------------------------
633
634 procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is
635 Loc : constant Source_Ptr := Sloc (N);
636
637 Var_List : constant Elist_Id := New_Elmt_List;
638 -- List of globals referenced by body of procedure
639
640 Call_List : constant Elist_Id := New_Elmt_List;
641 -- List of recursive calls in body of procedure
642
643 Shad_List : constant Elist_Id := New_Elmt_List;
644 -- List of entity id's for entities created to capture the value of
645 -- referenced globals on entry to the procedure.
646
647 Scop : constant Uint := Scope_Depth (Spec);
648 -- This is used to record the scope depth of the current procedure, so
649 -- that we can identify global references.
650
651 Max_Vars : constant := 4;
652 -- Do not test more than four global variables
653
654 Count_Vars : Natural := 0;
655 -- Count variables found so far
656
657 Var : Entity_Id;
658 Elm : Elmt_Id;
659 Ent : Entity_Id;
660 Call : Elmt_Id;
661 Decl : Node_Id;
662 Test : Node_Id;
663 Elm1 : Elmt_Id;
664 Elm2 : Elmt_Id;
665 Last : Node_Id;
666
667 function Process (Nod : Node_Id) return Traverse_Result;
668 -- Function to traverse the subprogram body (using Traverse_Func)
669
670 -------------
671 -- Process --
672 -------------
673
674 function Process (Nod : Node_Id) return Traverse_Result is
675 begin
676 -- Procedure call
677
678 if Nkind (Nod) = N_Procedure_Call_Statement then
679
680 -- Case of one of the detected recursive calls
681
682 if Is_Entity_Name (Name (Nod))
683 and then Has_Recursive_Call (Entity (Name (Nod)))
684 and then Entity (Name (Nod)) = Spec
685 then
686 Append_Elmt (Nod, Call_List);
687 return Skip;
688
689 -- Any other procedure call may have side effects
690
691 else
692 return Abandon;
693 end if;
694
695 -- A call to a pure function can always be ignored
696
697 elsif Nkind (Nod) = N_Function_Call
698 and then Is_Entity_Name (Name (Nod))
699 and then Is_Pure (Entity (Name (Nod)))
700 then
701 return Skip;
702
703 -- Case of an identifier reference
704
705 elsif Nkind (Nod) = N_Identifier then
706 Ent := Entity (Nod);
707
708 -- If no entity, then ignore the reference
709
710 -- Not clear why this can happen. To investigate, remove this
711 -- test and look at the crash that occurs here in 3401-004 ???
712
713 if No (Ent) then
714 return Skip;
715
716 -- Ignore entities with no Scope, again not clear how this
717 -- can happen, to investigate, look at 4108-008 ???
718
719 elsif No (Scope (Ent)) then
720 return Skip;
721
722 -- Ignore the reference if not to a more global object
723
724 elsif Scope_Depth (Scope (Ent)) >= Scop then
725 return Skip;
726
727 -- References to types, exceptions and constants are always OK
728
729 elsif Is_Type (Ent)
730 or else Ekind (Ent) = E_Exception
731 or else Ekind (Ent) = E_Constant
732 then
733 return Skip;
734
735 -- If other than a non-volatile scalar variable, we have some
736 -- kind of global reference (e.g. to a function) that we cannot
737 -- deal with so we forget the attempt.
738
739 elsif Ekind (Ent) /= E_Variable
740 or else not Is_Scalar_Type (Etype (Ent))
741 or else Treat_As_Volatile (Ent)
742 then
743 return Abandon;
744
745 -- Otherwise we have a reference to a global scalar
746
747 else
748 -- Loop through global entities already detected
749
750 Elm := First_Elmt (Var_List);
751 loop
752 -- If not detected before, record this new global reference
753
754 if No (Elm) then
755 Count_Vars := Count_Vars + 1;
756
757 if Count_Vars <= Max_Vars then
758 Append_Elmt (Entity (Nod), Var_List);
759 else
760 return Abandon;
761 end if;
762
763 exit;
764
765 -- If recorded before, ignore
766
767 elsif Node (Elm) = Entity (Nod) then
768 return Skip;
769
770 -- Otherwise keep looking
771
772 else
773 Next_Elmt (Elm);
774 end if;
775 end loop;
776
777 return Skip;
778 end if;
779
780 -- For all other node kinds, recursively visit syntactic children
781
782 else
783 return OK;
784 end if;
785 end Process;
786
787 function Traverse_Body is new Traverse_Func (Process);
788
789 -- Start of processing for Detect_Infinite_Recursion
790
791 begin
792 -- Do not attempt detection in No_Implicit_Conditional mode, since we
793 -- won't be able to generate the code to handle the recursion in any
794 -- case.
795
796 if Restriction_Active (No_Implicit_Conditionals) then
797 return;
798 end if;
799
800 -- Otherwise do traversal and quit if we get abandon signal
801
802 if Traverse_Body (N) = Abandon then
803 return;
804
805 -- We must have a call, since Has_Recursive_Call was set. If not just
806 -- ignore (this is only an error check, so if we have a funny situation,
807 -- due to bugs or errors, we do not want to bomb!)
808
809 elsif Is_Empty_Elmt_List (Call_List) then
810 return;
811 end if;
812
813 -- Here is the case where we detect recursion at compile time
814
815 -- Push our current scope for analyzing the declarations and code that
816 -- we will insert for the checking.
817
818 Push_Scope (Spec);
819
820 -- This loop builds temporary variables for each of the referenced
821 -- globals, so that at the end of the loop the list Shad_List contains
822 -- these temporaries in one-to-one correspondence with the elements in
823 -- Var_List.
824
825 Last := Empty;
826 Elm := First_Elmt (Var_List);
827 while Present (Elm) loop
828 Var := Node (Elm);
829 Ent := Make_Temporary (Loc, 'S');
830 Append_Elmt (Ent, Shad_List);
831
832 -- Insert a declaration for this temporary at the start of the
833 -- declarations for the procedure. The temporaries are declared as
834 -- constant objects initialized to the current values of the
835 -- corresponding temporaries.
836
837 Decl :=
838 Make_Object_Declaration (Loc,
839 Defining_Identifier => Ent,
840 Object_Definition => New_Occurrence_Of (Etype (Var), Loc),
841 Constant_Present => True,
842 Expression => New_Occurrence_Of (Var, Loc));
843
844 if No (Last) then
845 Prepend (Decl, Declarations (N));
846 else
847 Insert_After (Last, Decl);
848 end if;
849
850 Last := Decl;
851 Analyze (Decl);
852 Next_Elmt (Elm);
853 end loop;
854
855 -- Loop through calls
856
857 Call := First_Elmt (Call_List);
858 while Present (Call) loop
859
860 -- Build a predicate expression of the form
861
862 -- True
863 -- and then global1 = temp1
864 -- and then global2 = temp2
865 -- ...
866
867 -- This predicate determines if any of the global values
868 -- referenced by the procedure have changed since the
869 -- current call, if not an infinite recursion is assured.
870
871 Test := New_Occurrence_Of (Standard_True, Loc);
872
873 Elm1 := First_Elmt (Var_List);
874 Elm2 := First_Elmt (Shad_List);
875 while Present (Elm1) loop
876 Test :=
877 Make_And_Then (Loc,
878 Left_Opnd => Test,
879 Right_Opnd =>
880 Make_Op_Eq (Loc,
881 Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc),
882 Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc)));
883
884 Next_Elmt (Elm1);
885 Next_Elmt (Elm2);
886 end loop;
887
888 -- Now we replace the call with the sequence
889
890 -- if no-changes (see above) then
891 -- raise Storage_Error;
892 -- else
893 -- original-call
894 -- end if;
895
896 Rewrite (Node (Call),
897 Make_If_Statement (Loc,
898 Condition => Test,
899 Then_Statements => New_List (
900 Make_Raise_Storage_Error (Loc,
901 Reason => SE_Infinite_Recursion)),
902
903 Else_Statements => New_List (
904 Relocate_Node (Node (Call)))));
905
906 Analyze (Node (Call));
907
908 Next_Elmt (Call);
909 end loop;
910
911 -- Remove temporary scope stack entry used for analysis
912
913 Pop_Scope;
914 end Detect_Infinite_Recursion;
915
916 --------------------
917 -- Expand_Actuals --
918 --------------------
919
920 procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id) is
921 Loc : constant Source_Ptr := Sloc (N);
922 Actual : Node_Id;
923 Formal : Entity_Id;
924 N_Node : Node_Id;
925 Post_Call : List_Id;
926 E_Formal : Entity_Id;
927
928 procedure Add_Call_By_Copy_Code;
929 -- For cases where the parameter must be passed by copy, this routine
930 -- generates a temporary variable into which the actual is copied and
931 -- then passes this as the parameter. For an OUT or IN OUT parameter,
932 -- an assignment is also generated to copy the result back. The call
933 -- also takes care of any constraint checks required for the type
934 -- conversion case (on both the way in and the way out).
935
936 procedure Add_Simple_Call_By_Copy_Code;
937 -- This is similar to the above, but is used in cases where we know
938 -- that all that is needed is to simply create a temporary and copy
939 -- the value in and out of the temporary.
940
941 procedure Check_Fortran_Logical;
942 -- A value of type Logical that is passed through a formal parameter
943 -- must be normalized because .TRUE. usually does not have the same
944 -- representation as True. We assume that .FALSE. = False = 0.
945 -- What about functions that return a logical type ???
946
947 function Is_Legal_Copy return Boolean;
948 -- Check that an actual can be copied before generating the temporary
949 -- to be used in the call. If the actual is of a by_reference type then
950 -- the program is illegal (this can only happen in the presence of
951 -- rep. clauses that force an incorrect alignment). If the formal is
952 -- a by_reference parameter imposed by a DEC pragma, emit a warning to
953 -- the effect that this might lead to unaligned arguments.
954
955 function Make_Var (Actual : Node_Id) return Entity_Id;
956 -- Returns an entity that refers to the given actual parameter,
957 -- Actual (not including any type conversion). If Actual is an
958 -- entity name, then this entity is returned unchanged, otherwise
959 -- a renaming is created to provide an entity for the actual.
960
961 procedure Reset_Packed_Prefix;
962 -- The expansion of a packed array component reference is delayed in
963 -- the context of a call. Now we need to complete the expansion, so we
964 -- unmark the analyzed bits in all prefixes.
965
966 ---------------------------
967 -- Add_Call_By_Copy_Code --
968 ---------------------------
969
970 procedure Add_Call_By_Copy_Code is
971 Expr : Node_Id;
972 Init : Node_Id;
973 Temp : Entity_Id;
974 Indic : Node_Id;
975 Var : Entity_Id;
976 F_Typ : constant Entity_Id := Etype (Formal);
977 V_Typ : Entity_Id;
978 Crep : Boolean;
979
980 begin
981 if not Is_Legal_Copy then
982 return;
983 end if;
984
985 Temp := Make_Temporary (Loc, 'T', Actual);
986
987 -- Use formal type for temp, unless formal type is an unconstrained
988 -- array, in which case we don't have to worry about bounds checks,
989 -- and we use the actual type, since that has appropriate bounds.
990
991 if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then
992 Indic := New_Occurrence_Of (Etype (Actual), Loc);
993 else
994 Indic := New_Occurrence_Of (Etype (Formal), Loc);
995 end if;
996
997 if Nkind (Actual) = N_Type_Conversion then
998 V_Typ := Etype (Expression (Actual));
999
1000 -- If the formal is an (in-)out parameter, capture the name
1001 -- of the variable in order to build the post-call assignment.
1002
1003 Var := Make_Var (Expression (Actual));
1004
1005 Crep := not Same_Representation
1006 (F_Typ, Etype (Expression (Actual)));
1007
1008 else
1009 V_Typ := Etype (Actual);
1010 Var := Make_Var (Actual);
1011 Crep := False;
1012 end if;
1013
1014 -- Setup initialization for case of in out parameter, or an out
1015 -- parameter where the formal is an unconstrained array (in the
1016 -- latter case, we have to pass in an object with bounds).
1017
1018 -- If this is an out parameter, the initial copy is wasteful, so as
1019 -- an optimization for the one-dimensional case we extract the
1020 -- bounds of the actual and build an uninitialized temporary of the
1021 -- right size.
1022
1023 if Ekind (Formal) = E_In_Out_Parameter
1024 or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ))
1025 then
1026 if Nkind (Actual) = N_Type_Conversion then
1027 if Conversion_OK (Actual) then
1028 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1029 else
1030 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1031 end if;
1032
1033 elsif Ekind (Formal) = E_Out_Parameter
1034 and then Is_Array_Type (F_Typ)
1035 and then Number_Dimensions (F_Typ) = 1
1036 and then not Has_Non_Null_Base_Init_Proc (F_Typ)
1037 then
1038 -- Actual is a one-dimensional array or slice, and the type
1039 -- requires no initialization. Create a temporary of the
1040 -- right size, but do not copy actual into it (optimization).
1041
1042 Init := Empty;
1043 Indic :=
1044 Make_Subtype_Indication (Loc,
1045 Subtype_Mark =>
1046 New_Occurrence_Of (F_Typ, Loc),
1047 Constraint =>
1048 Make_Index_Or_Discriminant_Constraint (Loc,
1049 Constraints => New_List (
1050 Make_Range (Loc,
1051 Low_Bound =>
1052 Make_Attribute_Reference (Loc,
1053 Prefix => New_Occurrence_Of (Var, Loc),
1054 Attribute_Name => Name_First),
1055 High_Bound =>
1056 Make_Attribute_Reference (Loc,
1057 Prefix => New_Occurrence_Of (Var, Loc),
1058 Attribute_Name => Name_Last)))));
1059
1060 else
1061 Init := New_Occurrence_Of (Var, Loc);
1062 end if;
1063
1064 -- An initialization is created for packed conversions as
1065 -- actuals for out parameters to enable Make_Object_Declaration
1066 -- to determine the proper subtype for N_Node. Note that this
1067 -- is wasteful because the extra copying on the call side is
1068 -- not required for such out parameters. ???
1069
1070 elsif Ekind (Formal) = E_Out_Parameter
1071 and then Nkind (Actual) = N_Type_Conversion
1072 and then (Is_Bit_Packed_Array (F_Typ)
1073 or else
1074 Is_Bit_Packed_Array (Etype (Expression (Actual))))
1075 then
1076 if Conversion_OK (Actual) then
1077 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1078 else
1079 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1080 end if;
1081
1082 elsif Ekind (Formal) = E_In_Parameter then
1083
1084 -- Handle the case in which the actual is a type conversion
1085
1086 if Nkind (Actual) = N_Type_Conversion then
1087 if Conversion_OK (Actual) then
1088 Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1089 else
1090 Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc));
1091 end if;
1092 else
1093 Init := New_Occurrence_Of (Var, Loc);
1094 end if;
1095
1096 else
1097 Init := Empty;
1098 end if;
1099
1100 N_Node :=
1101 Make_Object_Declaration (Loc,
1102 Defining_Identifier => Temp,
1103 Object_Definition => Indic,
1104 Expression => Init);
1105 Set_Assignment_OK (N_Node);
1106 Insert_Action (N, N_Node);
1107
1108 -- Now, normally the deal here is that we use the defining
1109 -- identifier created by that object declaration. There is
1110 -- one exception to this. In the change of representation case
1111 -- the above declaration will end up looking like:
1112
1113 -- temp : type := identifier;
1114
1115 -- And in this case we might as well use the identifier directly
1116 -- and eliminate the temporary. Note that the analysis of the
1117 -- declaration was not a waste of time in that case, since it is
1118 -- what generated the necessary change of representation code. If
1119 -- the change of representation introduced additional code, as in
1120 -- a fixed-integer conversion, the expression is not an identifier
1121 -- and must be kept.
1122
1123 if Crep
1124 and then Present (Expression (N_Node))
1125 and then Is_Entity_Name (Expression (N_Node))
1126 then
1127 Temp := Entity (Expression (N_Node));
1128 Rewrite (N_Node, Make_Null_Statement (Loc));
1129 end if;
1130
1131 -- For IN parameter, all we do is to replace the actual
1132
1133 if Ekind (Formal) = E_In_Parameter then
1134 Rewrite (Actual, New_Reference_To (Temp, Loc));
1135 Analyze (Actual);
1136
1137 -- Processing for OUT or IN OUT parameter
1138
1139 else
1140 -- Kill current value indications for the temporary variable we
1141 -- created, since we just passed it as an OUT parameter.
1142
1143 Kill_Current_Values (Temp);
1144 Set_Is_Known_Valid (Temp, False);
1145
1146 -- If type conversion, use reverse conversion on exit
1147
1148 if Nkind (Actual) = N_Type_Conversion then
1149 if Conversion_OK (Actual) then
1150 Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc));
1151 else
1152 Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc));
1153 end if;
1154 else
1155 Expr := New_Occurrence_Of (Temp, Loc);
1156 end if;
1157
1158 Rewrite (Actual, New_Reference_To (Temp, Loc));
1159 Analyze (Actual);
1160
1161 -- If the actual is a conversion of a packed reference, it may
1162 -- already have been expanded by Remove_Side_Effects, and the
1163 -- resulting variable is a temporary which does not designate
1164 -- the proper out-parameter, which may not be addressable. In
1165 -- that case, generate an assignment to the original expression
1166 -- (before expansion of the packed reference) so that the proper
1167 -- expansion of assignment to a packed component can take place.
1168
1169 declare
1170 Obj : Node_Id;
1171 Lhs : Node_Id;
1172
1173 begin
1174 if Is_Renaming_Of_Object (Var)
1175 and then Nkind (Renamed_Object (Var)) = N_Selected_Component
1176 and then Is_Entity_Name (Prefix (Renamed_Object (Var)))
1177 and then Nkind (Original_Node (Prefix (Renamed_Object (Var))))
1178 = N_Indexed_Component
1179 and then
1180 Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var))))
1181 then
1182 Obj := Renamed_Object (Var);
1183 Lhs :=
1184 Make_Selected_Component (Loc,
1185 Prefix =>
1186 New_Copy_Tree (Original_Node (Prefix (Obj))),
1187 Selector_Name => New_Copy (Selector_Name (Obj)));
1188 Reset_Analyzed_Flags (Lhs);
1189
1190 else
1191 Lhs := New_Occurrence_Of (Var, Loc);
1192 end if;
1193
1194 Set_Assignment_OK (Lhs);
1195
1196 Append_To (Post_Call,
1197 Make_Assignment_Statement (Loc,
1198 Name => Lhs,
1199 Expression => Expr));
1200 end;
1201 end if;
1202 end Add_Call_By_Copy_Code;
1203
1204 ----------------------------------
1205 -- Add_Simple_Call_By_Copy_Code --
1206 ----------------------------------
1207
1208 procedure Add_Simple_Call_By_Copy_Code is
1209 Temp : Entity_Id;
1210 Decl : Node_Id;
1211 Incod : Node_Id;
1212 Outcod : Node_Id;
1213 Lhs : Node_Id;
1214 Rhs : Node_Id;
1215 Indic : Node_Id;
1216 F_Typ : constant Entity_Id := Etype (Formal);
1217
1218 begin
1219 if not Is_Legal_Copy then
1220 return;
1221 end if;
1222
1223 -- Use formal type for temp, unless formal type is an unconstrained
1224 -- array, in which case we don't have to worry about bounds checks,
1225 -- and we use the actual type, since that has appropriate bounds.
1226
1227 if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then
1228 Indic := New_Occurrence_Of (Etype (Actual), Loc);
1229 else
1230 Indic := New_Occurrence_Of (Etype (Formal), Loc);
1231 end if;
1232
1233 -- Prepare to generate code
1234
1235 Reset_Packed_Prefix;
1236
1237 Temp := Make_Temporary (Loc, 'T', Actual);
1238 Incod := Relocate_Node (Actual);
1239 Outcod := New_Copy_Tree (Incod);
1240
1241 -- Generate declaration of temporary variable, initializing it
1242 -- with the input parameter unless we have an OUT formal or
1243 -- this is an initialization call.
1244
1245 -- If the formal is an out parameter with discriminants, the
1246 -- discriminants must be captured even if the rest of the object
1247 -- is in principle uninitialized, because the discriminants may
1248 -- be read by the called subprogram.
1249
1250 if Ekind (Formal) = E_Out_Parameter then
1251 Incod := Empty;
1252
1253 if Has_Discriminants (Etype (Formal)) then
1254 Indic := New_Occurrence_Of (Etype (Actual), Loc);
1255 end if;
1256
1257 elsif Inside_Init_Proc then
1258
1259 -- Could use a comment here to match comment below ???
1260
1261 if Nkind (Actual) /= N_Selected_Component
1262 or else
1263 not Has_Discriminant_Dependent_Constraint
1264 (Entity (Selector_Name (Actual)))
1265 then
1266 Incod := Empty;
1267
1268 -- Otherwise, keep the component in order to generate the proper
1269 -- actual subtype, that depends on enclosing discriminants.
1270
1271 else
1272 null;
1273 end if;
1274 end if;
1275
1276 Decl :=
1277 Make_Object_Declaration (Loc,
1278 Defining_Identifier => Temp,
1279 Object_Definition => Indic,
1280 Expression => Incod);
1281
1282 if Inside_Init_Proc
1283 and then No (Incod)
1284 then
1285 -- If the call is to initialize a component of a composite type,
1286 -- and the component does not depend on discriminants, use the
1287 -- actual type of the component. This is required in case the
1288 -- component is constrained, because in general the formal of the
1289 -- initialization procedure will be unconstrained. Note that if
1290 -- the component being initialized is constrained by an enclosing
1291 -- discriminant, the presence of the initialization in the
1292 -- declaration will generate an expression for the actual subtype.
1293
1294 Set_No_Initialization (Decl);
1295 Set_Object_Definition (Decl,
1296 New_Occurrence_Of (Etype (Actual), Loc));
1297 end if;
1298
1299 Insert_Action (N, Decl);
1300
1301 -- The actual is simply a reference to the temporary
1302
1303 Rewrite (Actual, New_Occurrence_Of (Temp, Loc));
1304
1305 -- Generate copy out if OUT or IN OUT parameter
1306
1307 if Ekind (Formal) /= E_In_Parameter then
1308 Lhs := Outcod;
1309 Rhs := New_Occurrence_Of (Temp, Loc);
1310
1311 -- Deal with conversion
1312
1313 if Nkind (Lhs) = N_Type_Conversion then
1314 Lhs := Expression (Lhs);
1315 Rhs := Convert_To (Etype (Actual), Rhs);
1316 end if;
1317
1318 Append_To (Post_Call,
1319 Make_Assignment_Statement (Loc,
1320 Name => Lhs,
1321 Expression => Rhs));
1322 Set_Assignment_OK (Name (Last (Post_Call)));
1323 end if;
1324 end Add_Simple_Call_By_Copy_Code;
1325
1326 ---------------------------
1327 -- Check_Fortran_Logical --
1328 ---------------------------
1329
1330 procedure Check_Fortran_Logical is
1331 Logical : constant Entity_Id := Etype (Formal);
1332 Var : Entity_Id;
1333
1334 -- Note: this is very incomplete, e.g. it does not handle arrays
1335 -- of logical values. This is really not the right approach at all???)
1336
1337 begin
1338 if Convention (Subp) = Convention_Fortran
1339 and then Root_Type (Etype (Formal)) = Standard_Boolean
1340 and then Ekind (Formal) /= E_In_Parameter
1341 then
1342 Var := Make_Var (Actual);
1343 Append_To (Post_Call,
1344 Make_Assignment_Statement (Loc,
1345 Name => New_Occurrence_Of (Var, Loc),
1346 Expression =>
1347 Unchecked_Convert_To (
1348 Logical,
1349 Make_Op_Ne (Loc,
1350 Left_Opnd => New_Occurrence_Of (Var, Loc),
1351 Right_Opnd =>
1352 Unchecked_Convert_To (
1353 Logical,
1354 New_Occurrence_Of (Standard_False, Loc))))));
1355 end if;
1356 end Check_Fortran_Logical;
1357
1358 -------------------
1359 -- Is_Legal_Copy --
1360 -------------------
1361
1362 function Is_Legal_Copy return Boolean is
1363 begin
1364 -- An attempt to copy a value of such a type can only occur if
1365 -- representation clauses give the actual a misaligned address.
1366
1367 if Is_By_Reference_Type (Etype (Formal)) then
1368 Error_Msg_N
1369 ("misaligned actual cannot be passed by reference", Actual);
1370 return False;
1371
1372 -- For users of Starlet, we assume that the specification of by-
1373 -- reference mechanism is mandatory. This may lead to unaligned
1374 -- objects but at least for DEC legacy code it is known to work.
1375 -- The warning will alert users of this code that a problem may
1376 -- be lurking.
1377
1378 elsif Mechanism (Formal) = By_Reference
1379 and then Is_Valued_Procedure (Scope (Formal))
1380 then
1381 Error_Msg_N
1382 ("by_reference actual may be misaligned?", Actual);
1383 return False;
1384
1385 else
1386 return True;
1387 end if;
1388 end Is_Legal_Copy;
1389
1390 --------------
1391 -- Make_Var --
1392 --------------
1393
1394 function Make_Var (Actual : Node_Id) return Entity_Id is
1395 Var : Entity_Id;
1396
1397 begin
1398 if Is_Entity_Name (Actual) then
1399 return Entity (Actual);
1400
1401 else
1402 Var := Make_Temporary (Loc, 'T', Actual);
1403
1404 N_Node :=
1405 Make_Object_Renaming_Declaration (Loc,
1406 Defining_Identifier => Var,
1407 Subtype_Mark =>
1408 New_Occurrence_Of (Etype (Actual), Loc),
1409 Name => Relocate_Node (Actual));
1410
1411 Insert_Action (N, N_Node);
1412 return Var;
1413 end if;
1414 end Make_Var;
1415
1416 -------------------------
1417 -- Reset_Packed_Prefix --
1418 -------------------------
1419
1420 procedure Reset_Packed_Prefix is
1421 Pfx : Node_Id := Actual;
1422 begin
1423 loop
1424 Set_Analyzed (Pfx, False);
1425 exit when
1426 not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component);
1427 Pfx := Prefix (Pfx);
1428 end loop;
1429 end Reset_Packed_Prefix;
1430
1431 -- Start of processing for Expand_Actuals
1432
1433 begin
1434 Post_Call := New_List;
1435
1436 Formal := First_Formal (Subp);
1437 Actual := First_Actual (N);
1438 while Present (Formal) loop
1439 E_Formal := Etype (Formal);
1440
1441 if Is_Scalar_Type (E_Formal)
1442 or else Nkind (Actual) = N_Slice
1443 then
1444 Check_Fortran_Logical;
1445
1446 -- RM 6.4.1 (11)
1447
1448 elsif Ekind (Formal) /= E_Out_Parameter then
1449
1450 -- The unusual case of the current instance of a protected type
1451 -- requires special handling. This can only occur in the context
1452 -- of a call within the body of a protected operation.
1453
1454 if Is_Entity_Name (Actual)
1455 and then Ekind (Entity (Actual)) = E_Protected_Type
1456 and then In_Open_Scopes (Entity (Actual))
1457 then
1458 if Scope (Subp) /= Entity (Actual) then
1459 Error_Msg_N ("operation outside protected type may not "
1460 & "call back its protected operations?", Actual);
1461 end if;
1462
1463 Rewrite (Actual,
1464 Expand_Protected_Object_Reference (N, Entity (Actual)));
1465 end if;
1466
1467 -- Ada 2005 (AI-318-02): If the actual parameter is a call to a
1468 -- build-in-place function, then a temporary return object needs
1469 -- to be created and access to it must be passed to the function.
1470 -- Currently we limit such functions to those with inherently
1471 -- limited result subtypes, but eventually we plan to expand the
1472 -- functions that are treated as build-in-place to include other
1473 -- composite result types.
1474
1475 if Ada_Version >= Ada_2005
1476 and then Is_Build_In_Place_Function_Call (Actual)
1477 then
1478 Make_Build_In_Place_Call_In_Anonymous_Context (Actual);
1479 end if;
1480
1481 Apply_Constraint_Check (Actual, E_Formal);
1482
1483 -- Out parameter case. No constraint checks on access type
1484 -- RM 6.4.1 (13)
1485
1486 elsif Is_Access_Type (E_Formal) then
1487 null;
1488
1489 -- RM 6.4.1 (14)
1490
1491 elsif Has_Discriminants (Base_Type (E_Formal))
1492 or else Has_Non_Null_Base_Init_Proc (E_Formal)
1493 then
1494 Apply_Constraint_Check (Actual, E_Formal);
1495
1496 -- RM 6.4.1 (15)
1497
1498 else
1499 Apply_Constraint_Check (Actual, Base_Type (E_Formal));
1500 end if;
1501
1502 -- Processing for IN-OUT and OUT parameters
1503
1504 if Ekind (Formal) /= E_In_Parameter then
1505
1506 -- For type conversions of arrays, apply length/range checks
1507
1508 if Is_Array_Type (E_Formal)
1509 and then Nkind (Actual) = N_Type_Conversion
1510 then
1511 if Is_Constrained (E_Formal) then
1512 Apply_Length_Check (Expression (Actual), E_Formal);
1513 else
1514 Apply_Range_Check (Expression (Actual), E_Formal);
1515 end if;
1516 end if;
1517
1518 -- If argument is a type conversion for a type that is passed
1519 -- by copy, then we must pass the parameter by copy.
1520
1521 if Nkind (Actual) = N_Type_Conversion
1522 and then
1523 (Is_Numeric_Type (E_Formal)
1524 or else Is_Access_Type (E_Formal)
1525 or else Is_Enumeration_Type (E_Formal)
1526 or else Is_Bit_Packed_Array (Etype (Formal))
1527 or else Is_Bit_Packed_Array (Etype (Expression (Actual)))
1528
1529 -- Also pass by copy if change of representation
1530
1531 or else not Same_Representation
1532 (Etype (Formal),
1533 Etype (Expression (Actual))))
1534 then
1535 Add_Call_By_Copy_Code;
1536
1537 -- References to components of bit packed arrays are expanded
1538 -- at this point, rather than at the point of analysis of the
1539 -- actuals, to handle the expansion of the assignment to
1540 -- [in] out parameters.
1541
1542 elsif Is_Ref_To_Bit_Packed_Array (Actual) then
1543 Add_Simple_Call_By_Copy_Code;
1544
1545 -- If a non-scalar actual is possibly bit-aligned, we need a copy
1546 -- because the back-end cannot cope with such objects. In other
1547 -- cases where alignment forces a copy, the back-end generates
1548 -- it properly. It should not be generated unconditionally in the
1549 -- front-end because it does not know precisely the alignment
1550 -- requirements of the target, and makes too conservative an
1551 -- estimate, leading to superfluous copies or spurious errors
1552 -- on by-reference parameters.
1553
1554 elsif Nkind (Actual) = N_Selected_Component
1555 and then
1556 Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual)))
1557 and then not Represented_As_Scalar (Etype (Formal))
1558 then
1559 Add_Simple_Call_By_Copy_Code;
1560
1561 -- References to slices of bit packed arrays are expanded
1562
1563 elsif Is_Ref_To_Bit_Packed_Slice (Actual) then
1564 Add_Call_By_Copy_Code;
1565
1566 -- References to possibly unaligned slices of arrays are expanded
1567
1568 elsif Is_Possibly_Unaligned_Slice (Actual) then
1569 Add_Call_By_Copy_Code;
1570
1571 -- Deal with access types where the actual subtype and the
1572 -- formal subtype are not the same, requiring a check.
1573
1574 -- It is necessary to exclude tagged types because of "downward
1575 -- conversion" errors.
1576
1577 elsif Is_Access_Type (E_Formal)
1578 and then not Same_Type (E_Formal, Etype (Actual))
1579 and then not Is_Tagged_Type (Designated_Type (E_Formal))
1580 then
1581 Add_Call_By_Copy_Code;
1582
1583 -- If the actual is not a scalar and is marked for volatile
1584 -- treatment, whereas the formal is not volatile, then pass
1585 -- by copy unless it is a by-reference type.
1586
1587 -- Note: we use Is_Volatile here rather than Treat_As_Volatile,
1588 -- because this is the enforcement of a language rule that applies
1589 -- only to "real" volatile variables, not e.g. to the address
1590 -- clause overlay case.
1591
1592 elsif Is_Entity_Name (Actual)
1593 and then Is_Volatile (Entity (Actual))
1594 and then not Is_By_Reference_Type (Etype (Actual))
1595 and then not Is_Scalar_Type (Etype (Entity (Actual)))
1596 and then not Is_Volatile (E_Formal)
1597 then
1598 Add_Call_By_Copy_Code;
1599
1600 elsif Nkind (Actual) = N_Indexed_Component
1601 and then Is_Entity_Name (Prefix (Actual))
1602 and then Has_Volatile_Components (Entity (Prefix (Actual)))
1603 then
1604 Add_Call_By_Copy_Code;
1605
1606 -- Add call-by-copy code for the case of scalar out parameters
1607 -- when it is not known at compile time that the subtype of the
1608 -- formal is a subrange of the subtype of the actual (or vice
1609 -- versa for in out parameters), in order to get range checks
1610 -- on such actuals. (Maybe this case should be handled earlier
1611 -- in the if statement???)
1612
1613 elsif Is_Scalar_Type (E_Formal)
1614 and then
1615 (not In_Subrange_Of (E_Formal, Etype (Actual))
1616 or else
1617 (Ekind (Formal) = E_In_Out_Parameter
1618 and then not In_Subrange_Of (Etype (Actual), E_Formal)))
1619 then
1620 -- Perhaps the setting back to False should be done within
1621 -- Add_Call_By_Copy_Code, since it could get set on other
1622 -- cases occurring above???
1623
1624 if Do_Range_Check (Actual) then
1625 Set_Do_Range_Check (Actual, False);
1626 end if;
1627
1628 Add_Call_By_Copy_Code;
1629 end if;
1630
1631 -- Processing for IN parameters
1632
1633 else
1634 -- For IN parameters is in the packed array case, we expand an
1635 -- indexed component (the circuit in Exp_Ch4 deliberately left
1636 -- indexed components appearing as actuals untouched, so that
1637 -- the special processing above for the OUT and IN OUT cases
1638 -- could be performed. We could make the test in Exp_Ch4 more
1639 -- complex and have it detect the parameter mode, but it is
1640 -- easier simply to handle all cases here.)
1641
1642 if Nkind (Actual) = N_Indexed_Component
1643 and then Is_Packed (Etype (Prefix (Actual)))
1644 then
1645 Reset_Packed_Prefix;
1646 Expand_Packed_Element_Reference (Actual);
1647
1648 -- If we have a reference to a bit packed array, we copy it, since
1649 -- the actual must be byte aligned.
1650
1651 -- Is this really necessary in all cases???
1652
1653 elsif Is_Ref_To_Bit_Packed_Array (Actual) then
1654 Add_Simple_Call_By_Copy_Code;
1655
1656 -- If a non-scalar actual is possibly unaligned, we need a copy
1657
1658 elsif Is_Possibly_Unaligned_Object (Actual)
1659 and then not Represented_As_Scalar (Etype (Formal))
1660 then
1661 Add_Simple_Call_By_Copy_Code;
1662
1663 -- Similarly, we have to expand slices of packed arrays here
1664 -- because the result must be byte aligned.
1665
1666 elsif Is_Ref_To_Bit_Packed_Slice (Actual) then
1667 Add_Call_By_Copy_Code;
1668
1669 -- Only processing remaining is to pass by copy if this is a
1670 -- reference to a possibly unaligned slice, since the caller
1671 -- expects an appropriately aligned argument.
1672
1673 elsif Is_Possibly_Unaligned_Slice (Actual) then
1674 Add_Call_By_Copy_Code;
1675
1676 -- An unusual case: a current instance of an enclosing task can be
1677 -- an actual, and must be replaced by a reference to self.
1678
1679 elsif Is_Entity_Name (Actual)
1680 and then Is_Task_Type (Entity (Actual))
1681 then
1682 if In_Open_Scopes (Entity (Actual)) then
1683 Rewrite (Actual,
1684 (Make_Function_Call (Loc,
1685 Name => New_Reference_To (RTE (RE_Self), Loc))));
1686 Analyze (Actual);
1687
1688 -- A task type cannot otherwise appear as an actual
1689
1690 else
1691 raise Program_Error;
1692 end if;
1693 end if;
1694 end if;
1695
1696 Next_Formal (Formal);
1697 Next_Actual (Actual);
1698 end loop;
1699
1700 -- Find right place to put post call stuff if it is present
1701
1702 if not Is_Empty_List (Post_Call) then
1703
1704 -- If call is not a list member, it must be the triggering statement
1705 -- of a triggering alternative or an entry call alternative, and we
1706 -- can add the post call stuff to the corresponding statement list.
1707
1708 if not Is_List_Member (N) then
1709 declare
1710 P : constant Node_Id := Parent (N);
1711
1712 begin
1713 pragma Assert (Nkind_In (P, N_Triggering_Alternative,
1714 N_Entry_Call_Alternative));
1715
1716 if Is_Non_Empty_List (Statements (P)) then
1717 Insert_List_Before_And_Analyze
1718 (First (Statements (P)), Post_Call);
1719 else
1720 Set_Statements (P, Post_Call);
1721 end if;
1722 end;
1723
1724 -- Otherwise, normal case where N is in a statement sequence,
1725 -- just put the post-call stuff after the call statement.
1726
1727 else
1728 Insert_Actions_After (N, Post_Call);
1729 end if;
1730 end if;
1731
1732 -- The call node itself is re-analyzed in Expand_Call
1733
1734 end Expand_Actuals;
1735
1736 -----------------
1737 -- Expand_Call --
1738 -----------------
1739
1740 -- This procedure handles expansion of function calls and procedure call
1741 -- statements (i.e. it serves as the body for Expand_N_Function_Call and
1742 -- Expand_N_Procedure_Call_Statement). Processing for calls includes:
1743
1744 -- Replace call to Raise_Exception by Raise_Exception_Always if possible
1745 -- Provide values of actuals for all formals in Extra_Formals list
1746 -- Replace "call" to enumeration literal function by literal itself
1747 -- Rewrite call to predefined operator as operator
1748 -- Replace actuals to in-out parameters that are numeric conversions,
1749 -- with explicit assignment to temporaries before and after the call.
1750 -- Remove optional actuals if First_Optional_Parameter specified.
1751
1752 -- Note that the list of actuals has been filled with default expressions
1753 -- during semantic analysis of the call. Only the extra actuals required
1754 -- for the 'Constrained attribute and for accessibility checks are added
1755 -- at this point.
1756
1757 procedure Expand_Call (N : Node_Id) is
1758 Loc : constant Source_Ptr := Sloc (N);
1759 Call_Node : Node_Id := N;
1760 Extra_Actuals : List_Id := No_List;
1761 Prev : Node_Id := Empty;
1762
1763 procedure Add_Actual_Parameter (Insert_Param : Node_Id);
1764 -- Adds one entry to the end of the actual parameter list. Used for
1765 -- default parameters and for extra actuals (for Extra_Formals). The
1766 -- argument is an N_Parameter_Association node.
1767
1768 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id);
1769 -- Adds an extra actual to the list of extra actuals. Expr is the
1770 -- expression for the value of the actual, EF is the entity for the
1771 -- extra formal.
1772
1773 function Inherited_From_Formal (S : Entity_Id) return Entity_Id;
1774 -- Within an instance, a type derived from a non-tagged formal derived
1775 -- type inherits from the original parent, not from the actual. The
1776 -- current derivation mechanism has the derived type inherit from the
1777 -- actual, which is only correct outside of the instance. If the
1778 -- subprogram is inherited, we test for this particular case through a
1779 -- convoluted tree traversal before setting the proper subprogram to be
1780 -- called.
1781
1782 function New_Value (From : Node_Id) return Node_Id;
1783 -- From is the original Expression. New_Value is equivalent to a call
1784 -- to Duplicate_Subexpr with an explicit dereference when From is an
1785 -- access parameter.
1786
1787 --------------------------
1788 -- Add_Actual_Parameter --
1789 --------------------------
1790
1791 procedure Add_Actual_Parameter (Insert_Param : Node_Id) is
1792 Actual_Expr : constant Node_Id :=
1793 Explicit_Actual_Parameter (Insert_Param);
1794
1795 begin
1796 -- Case of insertion is first named actual
1797
1798 if No (Prev) or else
1799 Nkind (Parent (Prev)) /= N_Parameter_Association
1800 then
1801 Set_Next_Named_Actual
1802 (Insert_Param, First_Named_Actual (Call_Node));
1803 Set_First_Named_Actual (Call_Node, Actual_Expr);
1804
1805 if No (Prev) then
1806 if No (Parameter_Associations (Call_Node)) then
1807 Set_Parameter_Associations (Call_Node, New_List);
1808 Append (Insert_Param, Parameter_Associations (Call_Node));
1809 end if;
1810 else
1811 Insert_After (Prev, Insert_Param);
1812 end if;
1813
1814 -- Case of insertion is not first named actual
1815
1816 else
1817 Set_Next_Named_Actual
1818 (Insert_Param, Next_Named_Actual (Parent (Prev)));
1819 Set_Next_Named_Actual (Parent (Prev), Actual_Expr);
1820 Append (Insert_Param, Parameter_Associations (Call_Node));
1821 end if;
1822
1823 Prev := Actual_Expr;
1824 end Add_Actual_Parameter;
1825
1826 ----------------------
1827 -- Add_Extra_Actual --
1828 ----------------------
1829
1830 procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is
1831 Loc : constant Source_Ptr := Sloc (Expr);
1832
1833 begin
1834 if Extra_Actuals = No_List then
1835 Extra_Actuals := New_List;
1836 Set_Parent (Extra_Actuals, Call_Node);
1837 end if;
1838
1839 Append_To (Extra_Actuals,
1840 Make_Parameter_Association (Loc,
1841 Selector_Name => Make_Identifier (Loc, Chars (EF)),
1842 Explicit_Actual_Parameter => Expr));
1843
1844 Analyze_And_Resolve (Expr, Etype (EF));
1845
1846 if Nkind (Call_Node) = N_Function_Call then
1847 Set_Is_Accessibility_Actual (Parent (Expr));
1848 end if;
1849 end Add_Extra_Actual;
1850
1851 ---------------------------
1852 -- Inherited_From_Formal --
1853 ---------------------------
1854
1855 function Inherited_From_Formal (S : Entity_Id) return Entity_Id is
1856 Par : Entity_Id;
1857 Gen_Par : Entity_Id;
1858 Gen_Prim : Elist_Id;
1859 Elmt : Elmt_Id;
1860 Indic : Node_Id;
1861
1862 begin
1863 -- If the operation is inherited, it is attached to the corresponding
1864 -- type derivation. If the parent in the derivation is a generic
1865 -- actual, it is a subtype of the actual, and we have to recover the
1866 -- original derived type declaration to find the proper parent.
1867
1868 if Nkind (Parent (S)) /= N_Full_Type_Declaration
1869 or else not Is_Derived_Type (Defining_Identifier (Parent (S)))
1870 or else Nkind (Type_Definition (Original_Node (Parent (S)))) /=
1871 N_Derived_Type_Definition
1872 or else not In_Instance
1873 then
1874 return Empty;
1875
1876 else
1877 Indic :=
1878 Subtype_Indication
1879 (Type_Definition (Original_Node (Parent (S))));
1880
1881 if Nkind (Indic) = N_Subtype_Indication then
1882 Par := Entity (Subtype_Mark (Indic));
1883 else
1884 Par := Entity (Indic);
1885 end if;
1886 end if;
1887
1888 if not Is_Generic_Actual_Type (Par)
1889 or else Is_Tagged_Type (Par)
1890 or else Nkind (Parent (Par)) /= N_Subtype_Declaration
1891 or else not In_Open_Scopes (Scope (Par))
1892 then
1893 return Empty;
1894 else
1895 Gen_Par := Generic_Parent_Type (Parent (Par));
1896 end if;
1897
1898 -- If the actual has no generic parent type, the formal is not
1899 -- a formal derived type, so nothing to inherit.
1900
1901 if No (Gen_Par) then
1902 return Empty;
1903 end if;
1904
1905 -- If the generic parent type is still the generic type, this is a
1906 -- private formal, not a derived formal, and there are no operations
1907 -- inherited from the formal.
1908
1909 if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then
1910 return Empty;
1911 end if;
1912
1913 Gen_Prim := Collect_Primitive_Operations (Gen_Par);
1914
1915 Elmt := First_Elmt (Gen_Prim);
1916 while Present (Elmt) loop
1917 if Chars (Node (Elmt)) = Chars (S) then
1918 declare
1919 F1 : Entity_Id;
1920 F2 : Entity_Id;
1921
1922 begin
1923 F1 := First_Formal (S);
1924 F2 := First_Formal (Node (Elmt));
1925 while Present (F1)
1926 and then Present (F2)
1927 loop
1928 if Etype (F1) = Etype (F2)
1929 or else Etype (F2) = Gen_Par
1930 then
1931 Next_Formal (F1);
1932 Next_Formal (F2);
1933 else
1934 Next_Elmt (Elmt);
1935 exit; -- not the right subprogram
1936 end if;
1937
1938 return Node (Elmt);
1939 end loop;
1940 end;
1941
1942 else
1943 Next_Elmt (Elmt);
1944 end if;
1945 end loop;
1946
1947 raise Program_Error;
1948 end Inherited_From_Formal;
1949
1950 ---------------
1951 -- New_Value --
1952 ---------------
1953
1954 function New_Value (From : Node_Id) return Node_Id is
1955 Res : constant Node_Id := Duplicate_Subexpr (From);
1956 begin
1957 if Is_Access_Type (Etype (From)) then
1958 return
1959 Make_Explicit_Dereference (Sloc (From),
1960 Prefix => Res);
1961 else
1962 return Res;
1963 end if;
1964 end New_Value;
1965
1966 -- Local variables
1967
1968 Remote : constant Boolean := Is_Remote_Call (Call_Node);
1969 Actual : Node_Id;
1970 Formal : Entity_Id;
1971 Orig_Subp : Entity_Id := Empty;
1972 Param_Count : Natural := 0;
1973 Parent_Formal : Entity_Id;
1974 Parent_Subp : Entity_Id;
1975 Scop : Entity_Id;
1976 Subp : Entity_Id;
1977
1978 Prev_Orig : Node_Id;
1979 -- Original node for an actual, which may have been rewritten. If the
1980 -- actual is a function call that has been transformed from a selected
1981 -- component, the original node is unanalyzed. Otherwise, it carries
1982 -- semantic information used to generate additional actuals.
1983
1984 CW_Interface_Formals_Present : Boolean := False;
1985
1986 -- Start of processing for Expand_Call
1987
1988 begin
1989 -- Ignore if previous error
1990
1991 if Nkind (Call_Node) in N_Has_Etype
1992 and then Etype (Call_Node) = Any_Type
1993 then
1994 return;
1995 end if;
1996
1997 -- Call using access to subprogram with explicit dereference
1998
1999 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
2000 Subp := Etype (Name (Call_Node));
2001 Parent_Subp := Empty;
2002
2003 -- Case of call to simple entry, where the Name is a selected component
2004 -- whose prefix is the task, and whose selector name is the entry name
2005
2006 elsif Nkind (Name (Call_Node)) = N_Selected_Component then
2007 Subp := Entity (Selector_Name (Name (Call_Node)));
2008 Parent_Subp := Empty;
2009
2010 -- Case of call to member of entry family, where Name is an indexed
2011 -- component, with the prefix being a selected component giving the
2012 -- task and entry family name, and the index being the entry index.
2013
2014 elsif Nkind (Name (Call_Node)) = N_Indexed_Component then
2015 Subp := Entity (Selector_Name (Prefix (Name (Call_Node))));
2016 Parent_Subp := Empty;
2017
2018 -- Normal case
2019
2020 else
2021 Subp := Entity (Name (Call_Node));
2022 Parent_Subp := Alias (Subp);
2023
2024 -- Replace call to Raise_Exception by call to Raise_Exception_Always
2025 -- if we can tell that the first parameter cannot possibly be null.
2026 -- This improves efficiency by avoiding a run-time test.
2027
2028 -- We do not do this if Raise_Exception_Always does not exist, which
2029 -- can happen in configurable run time profiles which provide only a
2030 -- Raise_Exception.
2031
2032 if Is_RTE (Subp, RE_Raise_Exception)
2033 and then RTE_Available (RE_Raise_Exception_Always)
2034 then
2035 declare
2036 FA : constant Node_Id :=
2037 Original_Node (First_Actual (Call_Node));
2038
2039 begin
2040 -- The case we catch is where the first argument is obtained
2041 -- using the Identity attribute (which must always be
2042 -- non-null).
2043
2044 if Nkind (FA) = N_Attribute_Reference
2045 and then Attribute_Name (FA) = Name_Identity
2046 then
2047 Subp := RTE (RE_Raise_Exception_Always);
2048 Set_Name (Call_Node, New_Occurrence_Of (Subp, Loc));
2049 end if;
2050 end;
2051 end if;
2052
2053 if Ekind (Subp) = E_Entry then
2054 Parent_Subp := Empty;
2055 end if;
2056 end if;
2057
2058 -- Ada 2005 (AI-345): We have a procedure call as a triggering
2059 -- alternative in an asynchronous select or as an entry call in
2060 -- a conditional or timed select. Check whether the procedure call
2061 -- is a renaming of an entry and rewrite it as an entry call.
2062
2063 if Ada_Version >= Ada_2005
2064 and then Nkind (Call_Node) = N_Procedure_Call_Statement
2065 and then
2066 ((Nkind (Parent (Call_Node)) = N_Triggering_Alternative
2067 and then Triggering_Statement (Parent (Call_Node)) = Call_Node)
2068 or else
2069 (Nkind (Parent (Call_Node)) = N_Entry_Call_Alternative
2070 and then Entry_Call_Statement (Parent (Call_Node)) = Call_Node))
2071 then
2072 declare
2073 Ren_Decl : Node_Id;
2074 Ren_Root : Entity_Id := Subp;
2075
2076 begin
2077 -- This may be a chain of renamings, find the root
2078
2079 if Present (Alias (Ren_Root)) then
2080 Ren_Root := Alias (Ren_Root);
2081 end if;
2082
2083 if Present (Original_Node (Parent (Parent (Ren_Root)))) then
2084 Ren_Decl := Original_Node (Parent (Parent (Ren_Root)));
2085
2086 if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then
2087 Rewrite (Call_Node,
2088 Make_Entry_Call_Statement (Loc,
2089 Name =>
2090 New_Copy_Tree (Name (Ren_Decl)),
2091 Parameter_Associations =>
2092 New_Copy_List_Tree
2093 (Parameter_Associations (Call_Node))));
2094
2095 return;
2096 end if;
2097 end if;
2098 end;
2099 end if;
2100
2101 -- First step, compute extra actuals, corresponding to any Extra_Formals
2102 -- present. Note that we do not access Extra_Formals directly, instead
2103 -- we simply note the presence of the extra formals as we process the
2104 -- regular formals collecting corresponding actuals in Extra_Actuals.
2105
2106 -- We also generate any required range checks for actuals for in formals
2107 -- as we go through the loop, since this is a convenient place to do it.
2108 -- (Though it seems that this would be better done in Expand_Actuals???)
2109
2110 Formal := First_Formal (Subp);
2111 Actual := First_Actual (Call_Node);
2112 Param_Count := 1;
2113 while Present (Formal) loop
2114
2115 -- Generate range check if required
2116
2117 if Do_Range_Check (Actual)
2118 and then Ekind (Formal) = E_In_Parameter
2119 then
2120 Set_Do_Range_Check (Actual, False);
2121 Generate_Range_Check
2122 (Actual, Etype (Formal), CE_Range_Check_Failed);
2123 end if;
2124
2125 -- Prepare to examine current entry
2126
2127 Prev := Actual;
2128 Prev_Orig := Original_Node (Prev);
2129
2130 -- Ada 2005 (AI-251): Check if any formal is a class-wide interface
2131 -- to expand it in a further round.
2132
2133 CW_Interface_Formals_Present :=
2134 CW_Interface_Formals_Present
2135 or else
2136 (Ekind (Etype (Formal)) = E_Class_Wide_Type
2137 and then Is_Interface (Etype (Etype (Formal))))
2138 or else
2139 (Ekind (Etype (Formal)) = E_Anonymous_Access_Type
2140 and then Is_Interface (Directly_Designated_Type
2141 (Etype (Etype (Formal)))));
2142
2143 -- Create possible extra actual for constrained case. Usually, the
2144 -- extra actual is of the form actual'constrained, but since this
2145 -- attribute is only available for unconstrained records, TRUE is
2146 -- expanded if the type of the formal happens to be constrained (for
2147 -- instance when this procedure is inherited from an unconstrained
2148 -- record to a constrained one) or if the actual has no discriminant
2149 -- (its type is constrained). An exception to this is the case of a
2150 -- private type without discriminants. In this case we pass FALSE
2151 -- because the object has underlying discriminants with defaults.
2152
2153 if Present (Extra_Constrained (Formal)) then
2154 if Ekind (Etype (Prev)) in Private_Kind
2155 and then not Has_Discriminants (Base_Type (Etype (Prev)))
2156 then
2157 Add_Extra_Actual
2158 (New_Occurrence_Of (Standard_False, Loc),
2159 Extra_Constrained (Formal));
2160
2161 elsif Is_Constrained (Etype (Formal))
2162 or else not Has_Discriminants (Etype (Prev))
2163 then
2164 Add_Extra_Actual
2165 (New_Occurrence_Of (Standard_True, Loc),
2166 Extra_Constrained (Formal));
2167
2168 -- Do not produce extra actuals for Unchecked_Union parameters.
2169 -- Jump directly to the end of the loop.
2170
2171 elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then
2172 goto Skip_Extra_Actual_Generation;
2173
2174 else
2175 -- If the actual is a type conversion, then the constrained
2176 -- test applies to the actual, not the target type.
2177
2178 declare
2179 Act_Prev : Node_Id;
2180
2181 begin
2182 -- Test for unchecked conversions as well, which can occur
2183 -- as out parameter actuals on calls to stream procedures.
2184
2185 Act_Prev := Prev;
2186 while Nkind_In (Act_Prev, N_Type_Conversion,
2187 N_Unchecked_Type_Conversion)
2188 loop
2189 Act_Prev := Expression (Act_Prev);
2190 end loop;
2191
2192 -- If the expression is a conversion of a dereference, this
2193 -- is internally generated code that manipulates addresses,
2194 -- e.g. when building interface tables. No check should
2195 -- occur in this case, and the discriminated object is not
2196 -- directly a hand.
2197
2198 if not Comes_From_Source (Actual)
2199 and then Nkind (Actual) = N_Unchecked_Type_Conversion
2200 and then Nkind (Act_Prev) = N_Explicit_Dereference
2201 then
2202 Add_Extra_Actual
2203 (New_Occurrence_Of (Standard_False, Loc),
2204 Extra_Constrained (Formal));
2205
2206 else
2207 Add_Extra_Actual
2208 (Make_Attribute_Reference (Sloc (Prev),
2209 Prefix =>
2210 Duplicate_Subexpr_No_Checks
2211 (Act_Prev, Name_Req => True),
2212 Attribute_Name => Name_Constrained),
2213 Extra_Constrained (Formal));
2214 end if;
2215 end;
2216 end if;
2217 end if;
2218
2219 -- Create possible extra actual for accessibility level
2220
2221 if Present (Extra_Accessibility (Formal)) then
2222
2223 -- Ada 2005 (AI-252): If the actual was rewritten as an Access
2224 -- attribute, then the original actual may be an aliased object
2225 -- occurring as the prefix in a call using "Object.Operation"
2226 -- notation. In that case we must pass the level of the object,
2227 -- so Prev_Orig is reset to Prev and the attribute will be
2228 -- processed by the code for Access attributes further below.
2229
2230 if Prev_Orig /= Prev
2231 and then Nkind (Prev) = N_Attribute_Reference
2232 and then
2233 Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access
2234 and then Is_Aliased_View (Prev_Orig)
2235 then
2236 Prev_Orig := Prev;
2237 end if;
2238
2239 -- Ada 2005 (AI-251): Thunks must propagate the extra actuals of
2240 -- accessibility levels.
2241
2242 if Ekind (Current_Scope) in Subprogram_Kind
2243 and then Is_Thunk (Current_Scope)
2244 then
2245 declare
2246 Parm_Ent : Entity_Id;
2247
2248 begin
2249 if Is_Controlling_Actual (Actual) then
2250
2251 -- Find the corresponding actual of the thunk
2252
2253 Parm_Ent := First_Entity (Current_Scope);
2254 for J in 2 .. Param_Count loop
2255 Next_Entity (Parm_Ent);
2256 end loop;
2257
2258 else pragma Assert (Is_Entity_Name (Actual));
2259 Parm_Ent := Entity (Actual);
2260 end if;
2261
2262 Add_Extra_Actual
2263 (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc),
2264 Extra_Accessibility (Formal));
2265 end;
2266
2267 elsif Is_Entity_Name (Prev_Orig) then
2268
2269 -- When passing an access parameter, or a renaming of an access
2270 -- parameter, as the actual to another access parameter we need
2271 -- to pass along the actual's own access level parameter. This
2272 -- is done if we are within the scope of the formal access
2273 -- parameter (if this is an inlined body the extra formal is
2274 -- irrelevant).
2275
2276 if (Is_Formal (Entity (Prev_Orig))
2277 or else
2278 (Present (Renamed_Object (Entity (Prev_Orig)))
2279 and then
2280 Is_Entity_Name (Renamed_Object (Entity (Prev_Orig)))
2281 and then
2282 Is_Formal
2283 (Entity (Renamed_Object (Entity (Prev_Orig))))))
2284 and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type
2285 and then In_Open_Scopes (Scope (Entity (Prev_Orig)))
2286 then
2287 declare
2288 Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig);
2289
2290 begin
2291 pragma Assert (Present (Parm_Ent));
2292
2293 if Present (Extra_Accessibility (Parm_Ent)) then
2294 Add_Extra_Actual
2295 (New_Occurrence_Of
2296 (Extra_Accessibility (Parm_Ent), Loc),
2297 Extra_Accessibility (Formal));
2298
2299 -- If the actual access parameter does not have an
2300 -- associated extra formal providing its scope level,
2301 -- then treat the actual as having library-level
2302 -- accessibility.
2303
2304 else
2305 Add_Extra_Actual
2306 (Make_Integer_Literal (Loc,
2307 Intval => Scope_Depth (Standard_Standard)),
2308 Extra_Accessibility (Formal));
2309 end if;
2310 end;
2311
2312 -- The actual is a normal access value, so just pass the level
2313 -- of the actual's access type.
2314
2315 else
2316 Add_Extra_Actual
2317 (Make_Integer_Literal (Loc,
2318 Intval => Type_Access_Level (Etype (Prev_Orig))),
2319 Extra_Accessibility (Formal));
2320 end if;
2321
2322 -- If the actual is an access discriminant, then pass the level
2323 -- of the enclosing object (RM05-3.10.2(12.4/2)).
2324
2325 elsif Nkind (Prev_Orig) = N_Selected_Component
2326 and then Ekind (Entity (Selector_Name (Prev_Orig))) =
2327 E_Discriminant
2328 and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) =
2329 E_Anonymous_Access_Type
2330 then
2331 Add_Extra_Actual
2332 (Make_Integer_Literal (Loc,
2333 Intval => Object_Access_Level (Prefix (Prev_Orig))),
2334 Extra_Accessibility (Formal));
2335
2336 -- All other cases
2337
2338 else
2339 case Nkind (Prev_Orig) is
2340
2341 when N_Attribute_Reference =>
2342 case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is
2343
2344 -- For X'Access, pass on the level of the prefix X
2345
2346 when Attribute_Access =>
2347 Add_Extra_Actual
2348 (Make_Integer_Literal (Loc,
2349 Intval =>
2350 Object_Access_Level
2351 (Prefix (Prev_Orig))),
2352 Extra_Accessibility (Formal));
2353
2354 -- Treat the unchecked attributes as library-level
2355
2356 when Attribute_Unchecked_Access |
2357 Attribute_Unrestricted_Access =>
2358 Add_Extra_Actual
2359 (Make_Integer_Literal (Loc,
2360 Intval => Scope_Depth (Standard_Standard)),
2361 Extra_Accessibility (Formal));
2362
2363 -- No other cases of attributes returning access
2364 -- values that can be passed to access parameters.
2365
2366 when others =>
2367 raise Program_Error;
2368
2369 end case;
2370
2371 -- For allocators we pass the level of the execution of the
2372 -- called subprogram, which is one greater than the current
2373 -- scope level.
2374
2375 when N_Allocator =>
2376 Add_Extra_Actual
2377 (Make_Integer_Literal (Loc,
2378 Intval => Scope_Depth (Current_Scope) + 1),
2379 Extra_Accessibility (Formal));
2380
2381 -- For other cases we simply pass the level of the actual's
2382 -- access type. The type is retrieved from Prev rather than
2383 -- Prev_Orig, because in some cases Prev_Orig denotes an
2384 -- original expression that has not been analyzed.
2385
2386 when others =>
2387 Add_Extra_Actual
2388 (Make_Integer_Literal (Loc,
2389 Intval => Type_Access_Level (Etype (Prev))),
2390 Extra_Accessibility (Formal));
2391 end case;
2392 end if;
2393 end if;
2394
2395 -- Perform the check of 4.6(49) that prevents a null value from being
2396 -- passed as an actual to an access parameter. Note that the check
2397 -- is elided in the common cases of passing an access attribute or
2398 -- access parameter as an actual. Also, we currently don't enforce
2399 -- this check for expander-generated actuals and when -gnatdj is set.
2400
2401 if Ada_Version >= Ada_2005 then
2402
2403 -- Ada 2005 (AI-231): Check null-excluding access types. Note that
2404 -- the intent of 6.4.1(13) is that null-exclusion checks should
2405 -- not be done for 'out' parameters, even though it refers only
2406 -- to constraint checks, and a null_exlusion is not a constraint.
2407 -- Note that AI05-0196-1 corrects this mistake in the RM.
2408
2409 if Is_Access_Type (Etype (Formal))
2410 and then Can_Never_Be_Null (Etype (Formal))
2411 and then Ekind (Formal) /= E_Out_Parameter
2412 and then Nkind (Prev) /= N_Raise_Constraint_Error
2413 and then (Known_Null (Prev)
2414 or else not Can_Never_Be_Null (Etype (Prev)))
2415 then
2416 Install_Null_Excluding_Check (Prev);
2417 end if;
2418
2419 -- Ada_Version < Ada_2005
2420
2421 else
2422 if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type
2423 or else Access_Checks_Suppressed (Subp)
2424 then
2425 null;
2426
2427 elsif Debug_Flag_J then
2428 null;
2429
2430 elsif not Comes_From_Source (Prev) then
2431 null;
2432
2433 elsif Is_Entity_Name (Prev)
2434 and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type
2435 then
2436 null;
2437
2438 elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then
2439 null;
2440
2441 -- Suppress null checks when passing to access parameters of Java
2442 -- and CIL subprograms. (Should this be done for other foreign
2443 -- conventions as well ???)
2444
2445 elsif Convention (Subp) = Convention_Java
2446 or else Convention (Subp) = Convention_CIL
2447 then
2448 null;
2449
2450 else
2451 Install_Null_Excluding_Check (Prev);
2452 end if;
2453 end if;
2454
2455 -- Perform appropriate validity checks on parameters that
2456 -- are entities.
2457
2458 if Validity_Checks_On then
2459 if (Ekind (Formal) = E_In_Parameter
2460 and then Validity_Check_In_Params)
2461 or else
2462 (Ekind (Formal) = E_In_Out_Parameter
2463 and then Validity_Check_In_Out_Params)
2464 then
2465 -- If the actual is an indexed component of a packed type (or
2466 -- is an indexed or selected component whose prefix recursively
2467 -- meets this condition), it has not been expanded yet. It will
2468 -- be copied in the validity code that follows, and has to be
2469 -- expanded appropriately, so reanalyze it.
2470
2471 -- What we do is just to unset analyzed bits on prefixes till
2472 -- we reach something that does not have a prefix.
2473
2474 declare
2475 Nod : Node_Id;
2476
2477 begin
2478 Nod := Actual;
2479 while Nkind_In (Nod, N_Indexed_Component,
2480 N_Selected_Component)
2481 loop
2482 Set_Analyzed (Nod, False);
2483 Nod := Prefix (Nod);
2484 end loop;
2485 end;
2486
2487 Ensure_Valid (Actual);
2488 end if;
2489 end if;
2490
2491 -- For IN OUT and OUT parameters, ensure that subscripts are valid
2492 -- since this is a left side reference. We only do this for calls
2493 -- from the source program since we assume that compiler generated
2494 -- calls explicitly generate any required checks. We also need it
2495 -- only if we are doing standard validity checks, since clearly it is
2496 -- not needed if validity checks are off, and in subscript validity
2497 -- checking mode, all indexed components are checked with a call
2498 -- directly from Expand_N_Indexed_Component.
2499
2500 if Comes_From_Source (Call_Node)
2501 and then Ekind (Formal) /= E_In_Parameter
2502 and then Validity_Checks_On
2503 and then Validity_Check_Default
2504 and then not Validity_Check_Subscripts
2505 then
2506 Check_Valid_Lvalue_Subscripts (Actual);
2507 end if;
2508
2509 -- Mark any scalar OUT parameter that is a simple variable as no
2510 -- longer known to be valid (unless the type is always valid). This
2511 -- reflects the fact that if an OUT parameter is never set in a
2512 -- procedure, then it can become invalid on the procedure return.
2513
2514 if Ekind (Formal) = E_Out_Parameter
2515 and then Is_Entity_Name (Actual)
2516 and then Ekind (Entity (Actual)) = E_Variable
2517 and then not Is_Known_Valid (Etype (Actual))
2518 then
2519 Set_Is_Known_Valid (Entity (Actual), False);
2520 end if;
2521
2522 -- For an OUT or IN OUT parameter, if the actual is an entity, then
2523 -- clear current values, since they can be clobbered. We are probably
2524 -- doing this in more places than we need to, but better safe than
2525 -- sorry when it comes to retaining bad current values!
2526
2527 if Ekind (Formal) /= E_In_Parameter
2528 and then Is_Entity_Name (Actual)
2529 and then Present (Entity (Actual))
2530 then
2531 declare
2532 Ent : constant Entity_Id := Entity (Actual);
2533 Sav : Node_Id;
2534
2535 begin
2536 -- For an OUT or IN OUT parameter that is an assignable entity,
2537 -- we do not want to clobber the Last_Assignment field, since
2538 -- if it is set, it was precisely because it is indeed an OUT
2539 -- or IN OUT parameter! We do reset the Is_Known_Valid flag
2540 -- since the subprogram could have returned in invalid value.
2541
2542 if (Ekind (Formal) = E_Out_Parameter
2543 or else
2544 Ekind (Formal) = E_In_Out_Parameter)
2545 and then Is_Assignable (Ent)
2546 then
2547 Sav := Last_Assignment (Ent);
2548 Kill_Current_Values (Ent);
2549 Set_Last_Assignment (Ent, Sav);
2550 Set_Is_Known_Valid (Ent, False);
2551
2552 -- For all other cases, just kill the current values
2553
2554 else
2555 Kill_Current_Values (Ent);
2556 end if;
2557 end;
2558 end if;
2559
2560 -- If the formal is class wide and the actual is an aggregate, force
2561 -- evaluation so that the back end who does not know about class-wide
2562 -- type, does not generate a temporary of the wrong size.
2563
2564 if not Is_Class_Wide_Type (Etype (Formal)) then
2565 null;
2566
2567 elsif Nkind (Actual) = N_Aggregate
2568 or else (Nkind (Actual) = N_Qualified_Expression
2569 and then Nkind (Expression (Actual)) = N_Aggregate)
2570 then
2571 Force_Evaluation (Actual);
2572 end if;
2573
2574 -- In a remote call, if the formal is of a class-wide type, check
2575 -- that the actual meets the requirements described in E.4(18).
2576
2577 if Remote and then Is_Class_Wide_Type (Etype (Formal)) then
2578 Insert_Action (Actual,
2579 Make_Transportable_Check (Loc,
2580 Duplicate_Subexpr_Move_Checks (Actual)));
2581 end if;
2582
2583 -- This label is required when skipping extra actual generation for
2584 -- Unchecked_Union parameters.
2585
2586 <<Skip_Extra_Actual_Generation>>
2587
2588 Param_Count := Param_Count + 1;
2589 Next_Actual (Actual);
2590 Next_Formal (Formal);
2591 end loop;
2592
2593 -- If we are expanding a rhs of an assignment we need to check if tag
2594 -- propagation is needed. You might expect this processing to be in
2595 -- Analyze_Assignment but has to be done earlier (bottom-up) because the
2596 -- assignment might be transformed to a declaration for an unconstrained
2597 -- value if the expression is classwide.
2598
2599 if Nkind (Call_Node) = N_Function_Call
2600 and then Is_Tag_Indeterminate (Call_Node)
2601 and then Is_Entity_Name (Name (Call_Node))
2602 then
2603 declare
2604 Ass : Node_Id := Empty;
2605
2606 begin
2607 if Nkind (Parent (Call_Node)) = N_Assignment_Statement then
2608 Ass := Parent (Call_Node);
2609
2610 elsif Nkind (Parent (Call_Node)) = N_Qualified_Expression
2611 and then Nkind (Parent (Parent (Call_Node))) =
2612 N_Assignment_Statement
2613 then
2614 Ass := Parent (Parent (Call_Node));
2615
2616 elsif Nkind (Parent (Call_Node)) = N_Explicit_Dereference
2617 and then Nkind (Parent (Parent (Call_Node))) =
2618 N_Assignment_Statement
2619 then
2620 Ass := Parent (Parent (Call_Node));
2621 end if;
2622
2623 if Present (Ass)
2624 and then Is_Class_Wide_Type (Etype (Name (Ass)))
2625 then
2626 if Is_Access_Type (Etype (Call_Node)) then
2627 if Designated_Type (Etype (Call_Node)) /=
2628 Root_Type (Etype (Name (Ass)))
2629 then
2630 Error_Msg_NE
2631 ("tag-indeterminate expression "
2632 & " must have designated type& (RM 5.2 (6))",
2633 Call_Node, Root_Type (Etype (Name (Ass))));
2634 else
2635 Propagate_Tag (Name (Ass), Call_Node);
2636 end if;
2637
2638 elsif Etype (Call_Node) /= Root_Type (Etype (Name (Ass))) then
2639 Error_Msg_NE
2640 ("tag-indeterminate expression must have type&"
2641 & "(RM 5.2 (6))",
2642 Call_Node, Root_Type (Etype (Name (Ass))));
2643
2644 else
2645 Propagate_Tag (Name (Ass), Call_Node);
2646 end if;
2647
2648 -- The call will be rewritten as a dispatching call, and
2649 -- expanded as such.
2650
2651 return;
2652 end if;
2653 end;
2654 end if;
2655
2656 -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand
2657 -- it to point to the correct secondary virtual table
2658
2659 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2660 and then CW_Interface_Formals_Present
2661 then
2662 Expand_Interface_Actuals (Call_Node);
2663 end if;
2664
2665 -- Deals with Dispatch_Call if we still have a call, before expanding
2666 -- extra actuals since this will be done on the re-analysis of the
2667 -- dispatching call. Note that we do not try to shorten the actual list
2668 -- for a dispatching call, it would not make sense to do so. Expansion
2669 -- of dispatching calls is suppressed when VM_Target, because the VM
2670 -- back-ends directly handle the generation of dispatching calls and
2671 -- would have to undo any expansion to an indirect call.
2672
2673 if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement)
2674 and then Present (Controlling_Argument (Call_Node))
2675 then
2676 declare
2677 Call_Typ : constant Entity_Id := Etype (Call_Node);
2678 Typ : constant Entity_Id := Find_Dispatching_Type (Subp);
2679 Eq_Prim_Op : Entity_Id := Empty;
2680 New_Call : Node_Id;
2681 Param : Node_Id;
2682 Prev_Call : Node_Id;
2683
2684 begin
2685 if not Is_Limited_Type (Typ) then
2686 Eq_Prim_Op := Find_Prim_Op (Typ, Name_Op_Eq);
2687 end if;
2688
2689 if Tagged_Type_Expansion then
2690 Expand_Dispatching_Call (Call_Node);
2691
2692 -- The following return is worrisome. Is it really OK to skip
2693 -- all remaining processing in this procedure ???
2694
2695 return;
2696
2697 -- VM targets
2698
2699 else
2700 Apply_Tag_Checks (Call_Node);
2701
2702 -- If this is a dispatching "=", we must first compare the
2703 -- tags so we generate: x.tag = y.tag and then x = y
2704
2705 if Subp = Eq_Prim_Op then
2706
2707 -- Mark the node as analyzed to avoid reanalizing this
2708 -- dispatching call (which would cause a never-ending loop)
2709
2710 Prev_Call := Relocate_Node (Call_Node);
2711 Set_Analyzed (Prev_Call);
2712
2713 Param := First_Actual (Call_Node);
2714 New_Call :=
2715 Make_And_Then (Loc,
2716 Left_Opnd =>
2717 Make_Op_Eq (Loc,
2718 Left_Opnd =>
2719 Make_Selected_Component (Loc,
2720 Prefix => New_Value (Param),
2721 Selector_Name =>
2722 New_Reference_To (First_Tag_Component (Typ),
2723 Loc)),
2724
2725 Right_Opnd =>
2726 Make_Selected_Component (Loc,
2727 Prefix =>
2728 Unchecked_Convert_To (Typ,
2729 New_Value (Next_Actual (Param))),
2730 Selector_Name =>
2731 New_Reference_To
2732 (First_Tag_Component (Typ), Loc))),
2733 Right_Opnd => Prev_Call);
2734
2735 Rewrite (Call_Node, New_Call);
2736
2737 Analyze_And_Resolve
2738 (Call_Node, Call_Typ, Suppress => All_Checks);
2739 end if;
2740
2741 -- Expansion of a dispatching call results in an indirect call,
2742 -- which in turn causes current values to be killed (see
2743 -- Resolve_Call), so on VM targets we do the call here to
2744 -- ensure consistent warnings between VM and non-VM targets.
2745
2746 Kill_Current_Values;
2747 end if;
2748
2749 -- If this is a dispatching "=" then we must update the reference
2750 -- to the call node because we generated:
2751 -- x.tag = y.tag and then x = y
2752
2753 if Subp = Eq_Prim_Op then
2754 Call_Node := Right_Opnd (Call_Node);
2755 end if;
2756 end;
2757 end if;
2758
2759 -- Similarly, expand calls to RCI subprograms on which pragma
2760 -- All_Calls_Remote applies. The rewriting will be reanalyzed
2761 -- later. Do this only when the call comes from source since we
2762 -- do not want such a rewriting to occur in expanded code.
2763
2764 if Is_All_Remote_Call (Call_Node) then
2765 Expand_All_Calls_Remote_Subprogram_Call (Call_Node);
2766
2767 -- Similarly, do not add extra actuals for an entry call whose entity
2768 -- is a protected procedure, or for an internal protected subprogram
2769 -- call, because it will be rewritten as a protected subprogram call
2770 -- and reanalyzed (see Expand_Protected_Subprogram_Call).
2771
2772 elsif Is_Protected_Type (Scope (Subp))
2773 and then (Ekind (Subp) = E_Procedure
2774 or else Ekind (Subp) = E_Function)
2775 then
2776 null;
2777
2778 -- During that loop we gathered the extra actuals (the ones that
2779 -- correspond to Extra_Formals), so now they can be appended.
2780
2781 else
2782 while Is_Non_Empty_List (Extra_Actuals) loop
2783 Add_Actual_Parameter (Remove_Head (Extra_Actuals));
2784 end loop;
2785 end if;
2786
2787 -- At this point we have all the actuals, so this is the point at which
2788 -- the various expansion activities for actuals is carried out.
2789
2790 Expand_Actuals (Call_Node, Subp);
2791
2792 -- If the subprogram is a renaming, or if it is inherited, replace it in
2793 -- the call with the name of the actual subprogram being called. If this
2794 -- is a dispatching call, the run-time decides what to call. The Alias
2795 -- attribute does not apply to entries.
2796
2797 if Nkind (Call_Node) /= N_Entry_Call_Statement
2798 and then No (Controlling_Argument (Call_Node))
2799 and then Present (Parent_Subp)
2800 then
2801 if Present (Inherited_From_Formal (Subp)) then
2802 Parent_Subp := Inherited_From_Formal (Subp);
2803 else
2804 Parent_Subp := Ultimate_Alias (Parent_Subp);
2805 end if;
2806
2807 -- The below setting of Entity is suspect, see F109-018 discussion???
2808
2809 Set_Entity (Name (Call_Node), Parent_Subp);
2810
2811 if Is_Abstract_Subprogram (Parent_Subp)
2812 and then not In_Instance
2813 then
2814 Error_Msg_NE
2815 ("cannot call abstract subprogram &!",
2816 Name (Call_Node), Parent_Subp);
2817 end if;
2818
2819 -- Inspect all formals of derived subprogram Subp. Compare parameter
2820 -- types with the parent subprogram and check whether an actual may
2821 -- need a type conversion to the corresponding formal of the parent
2822 -- subprogram.
2823
2824 -- Not clear whether intrinsic subprograms need such conversions. ???
2825
2826 if not Is_Intrinsic_Subprogram (Parent_Subp)
2827 or else Is_Generic_Instance (Parent_Subp)
2828 then
2829 declare
2830 procedure Convert (Act : Node_Id; Typ : Entity_Id);
2831 -- Rewrite node Act as a type conversion of Act to Typ. Analyze
2832 -- and resolve the newly generated construct.
2833
2834 -------------
2835 -- Convert --
2836 -------------
2837
2838 procedure Convert (Act : Node_Id; Typ : Entity_Id) is
2839 begin
2840 Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act)));
2841 Analyze (Act);
2842 Resolve (Act, Typ);
2843 end Convert;
2844
2845 -- Local variables
2846
2847 Actual_Typ : Entity_Id;
2848 Formal_Typ : Entity_Id;
2849 Parent_Typ : Entity_Id;
2850
2851 begin
2852 Actual := First_Actual (Call_Node);
2853 Formal := First_Formal (Subp);
2854 Parent_Formal := First_Formal (Parent_Subp);
2855 while Present (Formal) loop
2856 Actual_Typ := Etype (Actual);
2857 Formal_Typ := Etype (Formal);
2858 Parent_Typ := Etype (Parent_Formal);
2859
2860 -- For an IN parameter of a scalar type, the parent formal
2861 -- type and derived formal type differ or the parent formal
2862 -- type and actual type do not match statically.
2863
2864 if Is_Scalar_Type (Formal_Typ)
2865 and then Ekind (Formal) = E_In_Parameter
2866 and then Formal_Typ /= Parent_Typ
2867 and then
2868 not Subtypes_Statically_Match (Parent_Typ, Actual_Typ)
2869 and then not Raises_Constraint_Error (Actual)
2870 then
2871 Convert (Actual, Parent_Typ);
2872 Enable_Range_Check (Actual);
2873
2874 -- If the actual has been marked as requiring a range
2875 -- check, then generate it here.
2876
2877 if Do_Range_Check (Actual) then
2878 Set_Do_Range_Check (Actual, False);
2879 Generate_Range_Check
2880 (Actual, Etype (Formal), CE_Range_Check_Failed);
2881 end if;
2882
2883 -- For access types, the parent formal type and actual type
2884 -- differ.
2885
2886 elsif Is_Access_Type (Formal_Typ)
2887 and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ)
2888 then
2889 if Ekind (Formal) /= E_In_Parameter then
2890 Convert (Actual, Parent_Typ);
2891
2892 elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type
2893 and then Designated_Type (Parent_Typ) /=
2894 Designated_Type (Actual_Typ)
2895 and then not Is_Controlling_Formal (Formal)
2896 then
2897 -- This unchecked conversion is not necessary unless
2898 -- inlining is enabled, because in that case the type
2899 -- mismatch may become visible in the body about to be
2900 -- inlined.
2901
2902 Rewrite (Actual,
2903 Unchecked_Convert_To (Parent_Typ,
2904 Relocate_Node (Actual)));
2905 Analyze (Actual);
2906 Resolve (Actual, Parent_Typ);
2907 end if;
2908
2909 -- For array and record types, the parent formal type and
2910 -- derived formal type have different sizes or pragma Pack
2911 -- status.
2912
2913 elsif ((Is_Array_Type (Formal_Typ)
2914 and then Is_Array_Type (Parent_Typ))
2915 or else
2916 (Is_Record_Type (Formal_Typ)
2917 and then Is_Record_Type (Parent_Typ)))
2918 and then
2919 (Esize (Formal_Typ) /= Esize (Parent_Typ)
2920 or else Has_Pragma_Pack (Formal_Typ) /=
2921 Has_Pragma_Pack (Parent_Typ))
2922 then
2923 Convert (Actual, Parent_Typ);
2924 end if;
2925
2926 Next_Actual (Actual);
2927 Next_Formal (Formal);
2928 Next_Formal (Parent_Formal);
2929 end loop;
2930 end;
2931 end if;
2932
2933 Orig_Subp := Subp;
2934 Subp := Parent_Subp;
2935 end if;
2936
2937 -- Check for violation of No_Abort_Statements
2938
2939 if Is_RTE (Subp, RE_Abort_Task) then
2940 Check_Restriction (No_Abort_Statements, Call_Node);
2941
2942 -- Check for violation of No_Dynamic_Attachment
2943
2944 elsif RTU_Loaded (Ada_Interrupts)
2945 and then (Is_RTE (Subp, RE_Is_Reserved) or else
2946 Is_RTE (Subp, RE_Is_Attached) or else
2947 Is_RTE (Subp, RE_Current_Handler) or else
2948 Is_RTE (Subp, RE_Attach_Handler) or else
2949 Is_RTE (Subp, RE_Exchange_Handler) or else
2950 Is_RTE (Subp, RE_Detach_Handler) or else
2951 Is_RTE (Subp, RE_Reference))
2952 then
2953 Check_Restriction (No_Dynamic_Attachment, Call_Node);
2954 end if;
2955
2956 -- Deal with case where call is an explicit dereference
2957
2958 if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
2959
2960 -- Handle case of access to protected subprogram type
2961
2962 if Is_Access_Protected_Subprogram_Type
2963 (Base_Type (Etype (Prefix (Name (Call_Node)))))
2964 then
2965 -- If this is a call through an access to protected operation, the
2966 -- prefix has the form (object'address, operation'access). Rewrite
2967 -- as a for other protected calls: the object is the 1st parameter
2968 -- of the list of actuals.
2969
2970 declare
2971 Call : Node_Id;
2972 Parm : List_Id;
2973 Nam : Node_Id;
2974 Obj : Node_Id;
2975 Ptr : constant Node_Id := Prefix (Name (Call_Node));
2976
2977 T : constant Entity_Id :=
2978 Equivalent_Type (Base_Type (Etype (Ptr)));
2979
2980 D_T : constant Entity_Id :=
2981 Designated_Type (Base_Type (Etype (Ptr)));
2982
2983 begin
2984 Obj :=
2985 Make_Selected_Component (Loc,
2986 Prefix => Unchecked_Convert_To (T, Ptr),
2987 Selector_Name =>
2988 New_Occurrence_Of (First_Entity (T), Loc));
2989
2990 Nam :=
2991 Make_Selected_Component (Loc,
2992 Prefix => Unchecked_Convert_To (T, Ptr),
2993 Selector_Name =>
2994 New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc));
2995
2996 Nam :=
2997 Make_Explicit_Dereference (Loc,
2998 Prefix => Nam);
2999
3000 if Present (Parameter_Associations (Call_Node)) then
3001 Parm := Parameter_Associations (Call_Node);
3002 else
3003 Parm := New_List;
3004 end if;
3005
3006 Prepend (Obj, Parm);
3007
3008 if Etype (D_T) = Standard_Void_Type then
3009 Call :=
3010 Make_Procedure_Call_Statement (Loc,
3011 Name => Nam,
3012 Parameter_Associations => Parm);
3013 else
3014 Call :=
3015 Make_Function_Call (Loc,
3016 Name => Nam,
3017 Parameter_Associations => Parm);
3018 end if;
3019
3020 Set_First_Named_Actual (Call, First_Named_Actual (Call_Node));
3021 Set_Etype (Call, Etype (D_T));
3022
3023 -- We do not re-analyze the call to avoid infinite recursion.
3024 -- We analyze separately the prefix and the object, and set
3025 -- the checks on the prefix that would otherwise be emitted
3026 -- when resolving a call.
3027
3028 Rewrite (Call_Node, Call);
3029 Analyze (Nam);
3030 Apply_Access_Check (Nam);
3031 Analyze (Obj);
3032 return;
3033 end;
3034 end if;
3035 end if;
3036
3037 -- If this is a call to an intrinsic subprogram, then perform the
3038 -- appropriate expansion to the corresponding tree node and we
3039 -- are all done (since after that the call is gone!)
3040
3041 -- In the case where the intrinsic is to be processed by the back end,
3042 -- the call to Expand_Intrinsic_Call will do nothing, which is fine,
3043 -- since the idea in this case is to pass the call unchanged. If the
3044 -- intrinsic is an inherited unchecked conversion, and the derived type
3045 -- is the target type of the conversion, we must retain it as the return
3046 -- type of the expression. Otherwise the expansion below, which uses the
3047 -- parent operation, will yield the wrong type.
3048
3049 if Is_Intrinsic_Subprogram (Subp) then
3050 Expand_Intrinsic_Call (Call_Node, Subp);
3051
3052 if Nkind (Call_Node) = N_Unchecked_Type_Conversion
3053 and then Parent_Subp /= Orig_Subp
3054 and then Etype (Parent_Subp) /= Etype (Orig_Subp)
3055 then
3056 Set_Etype (Call_Node, Etype (Orig_Subp));
3057 end if;
3058
3059 return;
3060 end if;
3061
3062 if Ekind_In (Subp, E_Function, E_Procedure) then
3063
3064 -- We perform two simple optimization on calls:
3065
3066 -- a) replace calls to null procedures unconditionally;
3067
3068 -- b) for To_Address, just do an unchecked conversion. Not only is
3069 -- this efficient, but it also avoids order of elaboration problems
3070 -- when address clauses are inlined (address expression elaborated
3071 -- at the wrong point).
3072
3073 -- We perform these optimization regardless of whether we are in the
3074 -- main unit or in a unit in the context of the main unit, to ensure
3075 -- that tree generated is the same in both cases, for Inspector use.
3076
3077 if Is_RTE (Subp, RE_To_Address) then
3078 Rewrite (Call_Node,
3079 Unchecked_Convert_To
3080 (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node))));
3081 return;
3082
3083 elsif Is_Null_Procedure (Subp) then
3084 Rewrite (Call_Node, Make_Null_Statement (Loc));
3085 return;
3086 end if;
3087
3088 if Is_Inlined (Subp) then
3089
3090 Inlined_Subprogram : declare
3091 Bod : Node_Id;
3092 Must_Inline : Boolean := False;
3093 Spec : constant Node_Id := Unit_Declaration_Node (Subp);
3094 Scop : constant Entity_Id := Scope (Subp);
3095
3096 function In_Unfrozen_Instance return Boolean;
3097 -- If the subprogram comes from an instance in the same unit,
3098 -- and the instance is not yet frozen, inlining might trigger
3099 -- order-of-elaboration problems in gigi.
3100
3101 --------------------------
3102 -- In_Unfrozen_Instance --
3103 --------------------------
3104
3105 function In_Unfrozen_Instance return Boolean is
3106 S : Entity_Id;
3107
3108 begin
3109 S := Scop;
3110 while Present (S)
3111 and then S /= Standard_Standard
3112 loop
3113 if Is_Generic_Instance (S)
3114 and then Present (Freeze_Node (S))
3115 and then not Analyzed (Freeze_Node (S))
3116 then
3117 return True;
3118 end if;
3119
3120 S := Scope (S);
3121 end loop;
3122
3123 return False;
3124 end In_Unfrozen_Instance;
3125
3126 -- Start of processing for Inlined_Subprogram
3127
3128 begin
3129 -- Verify that the body to inline has already been seen, and
3130 -- that if the body is in the current unit the inlining does
3131 -- not occur earlier. This avoids order-of-elaboration problems
3132 -- in the back end.
3133
3134 -- This should be documented in sinfo/einfo ???
3135
3136 if No (Spec)
3137 or else Nkind (Spec) /= N_Subprogram_Declaration
3138 or else No (Body_To_Inline (Spec))
3139 then
3140 Must_Inline := False;
3141
3142 -- If this an inherited function that returns a private type,
3143 -- do not inline if the full view is an unconstrained array,
3144 -- because such calls cannot be inlined.
3145
3146 elsif Present (Orig_Subp)
3147 and then Is_Array_Type (Etype (Orig_Subp))
3148 and then not Is_Constrained (Etype (Orig_Subp))
3149 then
3150 Must_Inline := False;
3151
3152 elsif In_Unfrozen_Instance then
3153 Must_Inline := False;
3154
3155 else
3156 Bod := Body_To_Inline (Spec);
3157
3158 if (In_Extended_Main_Code_Unit (Call_Node)
3159 or else In_Extended_Main_Code_Unit (Parent (Call_Node))
3160 or else Has_Pragma_Inline_Always (Subp))
3161 and then (not In_Same_Extended_Unit (Sloc (Bod), Loc)
3162 or else
3163 Earlier_In_Extended_Unit (Sloc (Bod), Loc))
3164 then
3165 Must_Inline := True;
3166
3167 -- If we are compiling a package body that is not the main
3168 -- unit, it must be for inlining/instantiation purposes,
3169 -- in which case we inline the call to insure that the same
3170 -- temporaries are generated when compiling the body by
3171 -- itself. Otherwise link errors can occur.
3172
3173 -- If the function being called is itself in the main unit,
3174 -- we cannot inline, because there is a risk of double
3175 -- elaboration and/or circularity: the inlining can make
3176 -- visible a private entity in the body of the main unit,
3177 -- that gigi will see before its sees its proper definition.
3178
3179 elsif not (In_Extended_Main_Code_Unit (Call_Node))
3180 and then In_Package_Body
3181 then
3182 Must_Inline := not In_Extended_Main_Source_Unit (Subp);
3183 end if;
3184 end if;
3185
3186 if Must_Inline then
3187 Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);
3188
3189 else
3190 -- Let the back end handle it
3191
3192 Add_Inlined_Body (Subp);
3193
3194 if Front_End_Inlining
3195 and then Nkind (Spec) = N_Subprogram_Declaration
3196 and then (In_Extended_Main_Code_Unit (Call_Node))
3197 and then No (Body_To_Inline (Spec))
3198 and then not Has_Completion (Subp)
3199 and then In_Same_Extended_Unit (Sloc (Spec), Loc)
3200 then
3201 Cannot_Inline
3202 ("cannot inline& (body not seen yet)?", Call_Node, Subp);
3203 end if;
3204 end if;
3205 end Inlined_Subprogram;
3206 end if;
3207 end if;
3208
3209 -- Check for protected subprogram. This is either an intra-object call,
3210 -- or a protected function call. Protected procedure calls are rewritten
3211 -- as entry calls and handled accordingly.
3212
3213 -- In Ada 2005, this may be an indirect call to an access parameter that
3214 -- is an access_to_subprogram. In that case the anonymous type has a
3215 -- scope that is a protected operation, but the call is a regular one.
3216 -- In either case do not expand call if subprogram is eliminated.
3217
3218 Scop := Scope (Subp);
3219
3220 if Nkind (Call_Node) /= N_Entry_Call_Statement
3221 and then Is_Protected_Type (Scop)
3222 and then Ekind (Subp) /= E_Subprogram_Type
3223 and then not Is_Eliminated (Subp)
3224 then
3225 -- If the call is an internal one, it is rewritten as a call to the
3226 -- corresponding unprotected subprogram.
3227
3228 Expand_Protected_Subprogram_Call (Call_Node, Subp, Scop);
3229 end if;
3230
3231 -- Functions returning controlled objects need special attention:
3232 -- if the return type is limited, the context is an initialization
3233 -- and different processing applies. If the call is to a protected
3234 -- function, the expansion above will call Expand_Call recusively.
3235 -- To prevent a double attachment, check that the current call is
3236 -- not a rewriting of a protected function call.
3237
3238 if Needs_Finalization (Etype (Subp)) then
3239 if not Is_Immutably_Limited_Type (Etype (Subp))
3240 and then
3241 (No (First_Formal (Subp))
3242 or else
3243 not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
3244 then
3245 Expand_Ctrl_Function_Call (Call_Node);
3246
3247 -- Build-in-place function calls which appear in anonymous contexts
3248 -- need a transient scope to ensure the proper finalization of the
3249 -- intermediate result after its use.
3250
3251 elsif Is_Build_In_Place_Function_Call (Call_Node)
3252 and then Nkind_In (Parent (Call_Node), N_Attribute_Reference,
3253 N_Function_Call,
3254 N_Indexed_Component,
3255 N_Object_Renaming_Declaration,
3256 N_Procedure_Call_Statement,
3257 N_Selected_Component,
3258 N_Slice)
3259 then
3260 Establish_Transient_Scope (Call_Node, Sec_Stack => True);
3261 end if;
3262 end if;
3263
3264 -- Test for First_Optional_Parameter, and if so, truncate parameter list
3265 -- if there are optional parameters at the trailing end.
3266 -- Note: we never delete procedures for call via a pointer.
3267
3268 if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function)
3269 and then Present (First_Optional_Parameter (Subp))
3270 then
3271 declare
3272 Last_Keep_Arg : Node_Id;
3273
3274 begin
3275 -- Last_Keep_Arg will hold the last actual that should be kept.
3276 -- If it remains empty at the end, it means that all parameters
3277 -- are optional.
3278
3279 Last_Keep_Arg := Empty;
3280
3281 -- Find first optional parameter, must be present since we checked
3282 -- the validity of the parameter before setting it.
3283
3284 Formal := First_Formal (Subp);
3285 Actual := First_Actual (Call_Node);
3286 while Formal /= First_Optional_Parameter (Subp) loop
3287 Last_Keep_Arg := Actual;
3288 Next_Formal (Formal);
3289 Next_Actual (Actual);
3290 end loop;
3291
3292 -- We have Formal and Actual pointing to the first potentially
3293 -- droppable argument. We can drop all the trailing arguments
3294 -- whose actual matches the default. Note that we know that all
3295 -- remaining formals have defaults, because we checked that this
3296 -- requirement was met before setting First_Optional_Parameter.
3297
3298 -- We use Fully_Conformant_Expressions to check for identity
3299 -- between formals and actuals, which may miss some cases, but
3300 -- on the other hand, this is only an optimization (if we fail
3301 -- to truncate a parameter it does not affect functionality).
3302 -- So if the default is 3 and the actual is 1+2, we consider
3303 -- them unequal, which hardly seems worrisome.
3304
3305 while Present (Formal) loop
3306 if not Fully_Conformant_Expressions
3307 (Actual, Default_Value (Formal))
3308 then
3309 Last_Keep_Arg := Actual;
3310 end if;
3311
3312 Next_Formal (Formal);
3313 Next_Actual (Actual);
3314 end loop;
3315
3316 -- If no arguments, delete entire list, this is the easy case
3317
3318 if No (Last_Keep_Arg) then
3319 Set_Parameter_Associations (Call_Node, No_List);
3320 Set_First_Named_Actual (Call_Node, Empty);
3321
3322 -- Case where at the last retained argument is positional. This
3323 -- is also an easy case, since the retained arguments are already
3324 -- in the right form, and we don't need to worry about the order
3325 -- of arguments that get eliminated.
3326
3327 elsif Is_List_Member (Last_Keep_Arg) then
3328 while Present (Next (Last_Keep_Arg)) loop
3329 Discard_Node (Remove_Next (Last_Keep_Arg));
3330 end loop;
3331
3332 Set_First_Named_Actual (Call_Node, Empty);
3333
3334 -- This is the annoying case where the last retained argument
3335 -- is a named parameter. Since the original arguments are not
3336 -- in declaration order, we may have to delete some fairly
3337 -- random collection of arguments.
3338
3339 else
3340 declare
3341 Temp : Node_Id;
3342 Passoc : Node_Id;
3343
3344 begin
3345 -- First step, remove all the named parameters from the
3346 -- list (they are still chained using First_Named_Actual
3347 -- and Next_Named_Actual, so we have not lost them!)
3348
3349 Temp := First (Parameter_Associations (Call_Node));
3350
3351 -- Case of all parameters named, remove them all
3352
3353 if Nkind (Temp) = N_Parameter_Association then
3354 -- Suppress warnings to avoid warning on possible
3355 -- infinite loop (because Call_Node is not modified).
3356
3357 pragma Warnings (Off);
3358 while Is_Non_Empty_List
3359 (Parameter_Associations (Call_Node))
3360 loop
3361 Temp :=
3362 Remove_Head (Parameter_Associations (Call_Node));
3363 end loop;
3364 pragma Warnings (On);
3365
3366 -- Case of mixed positional/named, remove named parameters
3367
3368 else
3369 while Nkind (Next (Temp)) /= N_Parameter_Association loop
3370 Next (Temp);
3371 end loop;
3372
3373 while Present (Next (Temp)) loop
3374 Remove (Next (Temp));
3375 end loop;
3376 end if;
3377
3378 -- Now we loop through the named parameters, till we get
3379 -- to the last one to be retained, adding them to the list.
3380 -- Note that the Next_Named_Actual list does not need to be
3381 -- touched since we are only reordering them on the actual
3382 -- parameter association list.
3383
3384 Passoc := Parent (First_Named_Actual (Call_Node));
3385 loop
3386 Temp := Relocate_Node (Passoc);
3387 Append_To
3388 (Parameter_Associations (Call_Node), Temp);
3389 exit when
3390 Last_Keep_Arg = Explicit_Actual_Parameter (Passoc);
3391 Passoc := Parent (Next_Named_Actual (Passoc));
3392 end loop;
3393
3394 Set_Next_Named_Actual (Temp, Empty);
3395
3396 loop
3397 Temp := Next_Named_Actual (Passoc);
3398 exit when No (Temp);
3399 Set_Next_Named_Actual
3400 (Passoc, Next_Named_Actual (Parent (Temp)));
3401 end loop;
3402 end;
3403
3404 end if;
3405 end;
3406 end if;
3407 end Expand_Call;
3408
3409 --------------------------
3410 -- Expand_Inlined_Call --
3411 --------------------------
3412
3413 procedure Expand_Inlined_Call
3414 (N : Node_Id;
3415 Subp : Entity_Id;
3416 Orig_Subp : Entity_Id)
3417 is
3418 Loc : constant Source_Ptr := Sloc (N);
3419 Is_Predef : constant Boolean :=
3420 Is_Predefined_File_Name
3421 (Unit_File_Name (Get_Source_Unit (Subp)));
3422 Orig_Bod : constant Node_Id :=
3423 Body_To_Inline (Unit_Declaration_Node (Subp));
3424
3425 Blk : Node_Id;
3426 Bod : Node_Id;
3427 Decl : Node_Id;
3428 Decls : constant List_Id := New_List;
3429 Exit_Lab : Entity_Id := Empty;
3430 F : Entity_Id;
3431 A : Node_Id;
3432 Lab_Decl : Node_Id;
3433 Lab_Id : Node_Id;
3434 New_A : Node_Id;
3435 Num_Ret : Int := 0;
3436 Ret_Type : Entity_Id;
3437 Targ : Node_Id;
3438 Targ1 : Node_Id;
3439 Temp : Entity_Id;
3440 Temp_Typ : Entity_Id;
3441
3442 Return_Object : Entity_Id := Empty;
3443 -- Entity in declaration in an extended_return_statement
3444
3445 Is_Unc : constant Boolean :=
3446 Is_Array_Type (Etype (Subp))
3447 and then not Is_Constrained (Etype (Subp));
3448 -- If the type returned by the function is unconstrained and the call
3449 -- can be inlined, special processing is required.
3450
3451 procedure Make_Exit_Label;
3452 -- Build declaration for exit label to be used in Return statements,
3453 -- sets Exit_Lab (the label node) and Lab_Decl (corresponding implicit
3454 -- declaration). Does nothing if Exit_Lab already set.
3455
3456 function Process_Formals (N : Node_Id) return Traverse_Result;
3457 -- Replace occurrence of a formal with the corresponding actual, or the
3458 -- thunk generated for it.
3459
3460 function Process_Sloc (Nod : Node_Id) return Traverse_Result;
3461 -- If the call being expanded is that of an internal subprogram, set the
3462 -- sloc of the generated block to that of the call itself, so that the
3463 -- expansion is skipped by the "next" command in gdb.
3464 -- Same processing for a subprogram in a predefined file, e.g.
3465 -- Ada.Tags. If Debug_Generated_Code is true, suppress this change to
3466 -- simplify our own development.
3467
3468 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id);
3469 -- If the function body is a single expression, replace call with
3470 -- expression, else insert block appropriately.
3471
3472 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id);
3473 -- If procedure body has no local variables, inline body without
3474 -- creating block, otherwise rewrite call with block.
3475
3476 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean;
3477 -- Determine whether a formal parameter is used only once in Orig_Bod
3478
3479 ---------------------
3480 -- Make_Exit_Label --
3481 ---------------------
3482
3483 procedure Make_Exit_Label is
3484 Lab_Ent : Entity_Id;
3485 begin
3486 if No (Exit_Lab) then
3487 Lab_Ent := Make_Temporary (Loc, 'L');
3488 Lab_Id := New_Reference_To (Lab_Ent, Loc);
3489 Exit_Lab := Make_Label (Loc, Lab_Id);
3490 Lab_Decl :=
3491 Make_Implicit_Label_Declaration (Loc,
3492 Defining_Identifier => Lab_Ent,
3493 Label_Construct => Exit_Lab);
3494 end if;
3495 end Make_Exit_Label;
3496
3497 ---------------------
3498 -- Process_Formals --
3499 ---------------------
3500
3501 function Process_Formals (N : Node_Id) return Traverse_Result is
3502 A : Entity_Id;
3503 E : Entity_Id;
3504 Ret : Node_Id;
3505
3506 begin
3507 if Is_Entity_Name (N)
3508 and then Present (Entity (N))
3509 then
3510 E := Entity (N);
3511
3512 if Is_Formal (E)
3513 and then Scope (E) = Subp
3514 then
3515 A := Renamed_Object (E);
3516
3517 -- Rewrite the occurrence of the formal into an occurrence of
3518 -- the actual. Also establish visibility on the proper view of
3519 -- the actual's subtype for the body's context (if the actual's
3520 -- subtype is private at the call point but its full view is
3521 -- visible to the body, then the inlined tree here must be
3522 -- analyzed with the full view).
3523
3524 if Is_Entity_Name (A) then
3525 Rewrite (N, New_Occurrence_Of (Entity (A), Loc));
3526 Check_Private_View (N);
3527
3528 elsif Nkind (A) = N_Defining_Identifier then
3529 Rewrite (N, New_Occurrence_Of (A, Loc));
3530 Check_Private_View (N);
3531
3532 -- Numeric literal
3533
3534 else
3535 Rewrite (N, New_Copy (A));
3536 end if;
3537 end if;
3538 return Skip;
3539
3540 elsif Is_Entity_Name (N)
3541 and then Present (Return_Object)
3542 and then Chars (N) = Chars (Return_Object)
3543 then
3544 -- Occurrence within an extended return statement. The return
3545 -- object is local to the body been inlined, and thus the generic
3546 -- copy is not analyzed yet, so we match by name, and replace it
3547 -- with target of call.
3548
3549 if Nkind (Targ) = N_Defining_Identifier then
3550 Rewrite (N, New_Occurrence_Of (Targ, Loc));
3551 else
3552 Rewrite (N, New_Copy_Tree (Targ));
3553 end if;
3554
3555 return Skip;
3556
3557 elsif Nkind (N) = N_Simple_Return_Statement then
3558 if No (Expression (N)) then
3559 Make_Exit_Label;
3560 Rewrite (N,
3561 Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id)));
3562
3563 else
3564 if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements
3565 and then Nkind (Parent (Parent (N))) = N_Subprogram_Body
3566 then
3567 -- Function body is a single expression. No need for
3568 -- exit label.
3569
3570 null;
3571
3572 else
3573 Num_Ret := Num_Ret + 1;
3574 Make_Exit_Label;
3575 end if;
3576
3577 -- Because of the presence of private types, the views of the
3578 -- expression and the context may be different, so place an
3579 -- unchecked conversion to the context type to avoid spurious
3580 -- errors, e.g. when the expression is a numeric literal and
3581 -- the context is private. If the expression is an aggregate,
3582 -- use a qualified expression, because an aggregate is not a
3583 -- legal argument of a conversion.
3584
3585 if Nkind_In (Expression (N), N_Aggregate, N_Null) then
3586 Ret :=
3587 Make_Qualified_Expression (Sloc (N),
3588 Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)),
3589 Expression => Relocate_Node (Expression (N)));
3590 else
3591 Ret :=
3592 Unchecked_Convert_To
3593 (Ret_Type, Relocate_Node (Expression (N)));
3594 end if;
3595
3596 if Nkind (Targ) = N_Defining_Identifier then
3597 Rewrite (N,
3598 Make_Assignment_Statement (Loc,
3599 Name => New_Occurrence_Of (Targ, Loc),
3600 Expression => Ret));
3601 else
3602 Rewrite (N,
3603 Make_Assignment_Statement (Loc,
3604 Name => New_Copy (Targ),
3605 Expression => Ret));
3606 end if;
3607
3608 Set_Assignment_OK (Name (N));
3609
3610 if Present (Exit_Lab) then
3611 Insert_After (N,
3612 Make_Goto_Statement (Loc,
3613 Name => New_Copy (Lab_Id)));
3614 end if;
3615 end if;
3616
3617 return OK;
3618
3619 elsif Nkind (N) = N_Extended_Return_Statement then
3620
3621 -- An extended return becomes a block whose first statement is
3622 -- the assignment of the initial expression of the return object
3623 -- to the target of the call itself.
3624
3625 declare
3626 Return_Decl : constant Entity_Id :=
3627 First (Return_Object_Declarations (N));
3628 Assign : Node_Id;
3629
3630 begin
3631 Return_Object := Defining_Identifier (Return_Decl);
3632
3633 if Present (Expression (Return_Decl)) then
3634 if Nkind (Targ) = N_Defining_Identifier then
3635 Assign :=
3636 Make_Assignment_Statement (Loc,
3637 Name => New_Occurrence_Of (Targ, Loc),
3638 Expression => Expression (Return_Decl));
3639 else
3640 Assign :=
3641 Make_Assignment_Statement (Loc,
3642 Name => New_Copy (Targ),
3643 Expression => Expression (Return_Decl));
3644 end if;
3645
3646 Set_Assignment_OK (Name (Assign));
3647 Prepend (Assign,
3648 Statements (Handled_Statement_Sequence (N)));
3649 end if;
3650
3651 Rewrite (N,
3652 Make_Block_Statement (Loc,
3653 Handled_Statement_Sequence =>
3654 Handled_Statement_Sequence (N)));
3655
3656 return OK;
3657 end;
3658
3659 -- Remove pragma Unreferenced since it may refer to formals that
3660 -- are not visible in the inlined body, and in any case we will
3661 -- not be posting warnings on the inlined body so it is unneeded.
3662
3663 elsif Nkind (N) = N_Pragma
3664 and then Pragma_Name (N) = Name_Unreferenced
3665 then
3666 Rewrite (N, Make_Null_Statement (Sloc (N)));
3667 return OK;
3668
3669 else
3670 return OK;
3671 end if;
3672 end Process_Formals;
3673
3674 procedure Replace_Formals is new Traverse_Proc (Process_Formals);
3675
3676 ------------------
3677 -- Process_Sloc --
3678 ------------------
3679
3680 function Process_Sloc (Nod : Node_Id) return Traverse_Result is
3681 begin
3682 if not Debug_Generated_Code then
3683 Set_Sloc (Nod, Sloc (N));
3684 Set_Comes_From_Source (Nod, False);
3685 end if;
3686
3687 return OK;
3688 end Process_Sloc;
3689
3690 procedure Reset_Slocs is new Traverse_Proc (Process_Sloc);
3691
3692 ---------------------------
3693 -- Rewrite_Function_Call --
3694 ---------------------------
3695
3696 procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is
3697 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
3698 Fst : constant Node_Id := First (Statements (HSS));
3699
3700 begin
3701 -- Optimize simple case: function body is a single return statement,
3702 -- which has been expanded into an assignment.
3703
3704 if Is_Empty_List (Declarations (Blk))
3705 and then Nkind (Fst) = N_Assignment_Statement
3706 and then No (Next (Fst))
3707 then
3708
3709 -- The function call may have been rewritten as the temporary
3710 -- that holds the result of the call, in which case remove the
3711 -- now useless declaration.
3712
3713 if Nkind (N) = N_Identifier
3714 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
3715 then
3716 Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc));
3717 end if;
3718
3719 Rewrite (N, Expression (Fst));
3720
3721 elsif Nkind (N) = N_Identifier
3722 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
3723 then
3724 -- The block assigns the result of the call to the temporary
3725
3726 Insert_After (Parent (Entity (N)), Blk);
3727
3728 elsif Nkind (Parent (N)) = N_Assignment_Statement
3729 and then
3730 (Is_Entity_Name (Name (Parent (N)))
3731 or else
3732 (Nkind (Name (Parent (N))) = N_Explicit_Dereference
3733 and then Is_Entity_Name (Prefix (Name (Parent (N))))))
3734 then
3735 -- Replace assignment with the block
3736
3737 declare
3738 Original_Assignment : constant Node_Id := Parent (N);
3739
3740 begin
3741 -- Preserve the original assignment node to keep the complete
3742 -- assignment subtree consistent enough for Analyze_Assignment
3743 -- to proceed (specifically, the original Lhs node must still
3744 -- have an assignment statement as its parent).
3745
3746 -- We cannot rely on Original_Node to go back from the block
3747 -- node to the assignment node, because the assignment might
3748 -- already be a rewrite substitution.
3749
3750 Discard_Node (Relocate_Node (Original_Assignment));
3751 Rewrite (Original_Assignment, Blk);
3752 end;
3753
3754 elsif Nkind (Parent (N)) = N_Object_Declaration then
3755 Set_Expression (Parent (N), Empty);
3756 Insert_After (Parent (N), Blk);
3757
3758 elsif Is_Unc then
3759 Insert_Before (Parent (N), Blk);
3760 end if;
3761 end Rewrite_Function_Call;
3762
3763 ----------------------------
3764 -- Rewrite_Procedure_Call --
3765 ----------------------------
3766
3767 procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is
3768 HSS : constant Node_Id := Handled_Statement_Sequence (Blk);
3769 begin
3770 -- If there is a transient scope for N, this will be the scope of the
3771 -- actions for N, and the statements in Blk need to be within this
3772 -- scope. For example, they need to have visibility on the constant
3773 -- declarations created for the formals.
3774
3775 -- If N needs no transient scope, and if there are no declarations in
3776 -- the inlined body, we can do a little optimization and insert the
3777 -- statements for the body directly after N, and rewrite N to a
3778 -- null statement, instead of rewriting N into a full-blown block
3779 -- statement.
3780
3781 if not Scope_Is_Transient
3782 and then Is_Empty_List (Declarations (Blk))
3783 then
3784 Insert_List_After (N, Statements (HSS));
3785 Rewrite (N, Make_Null_Statement (Loc));
3786 else
3787 Rewrite (N, Blk);
3788 end if;
3789 end Rewrite_Procedure_Call;
3790
3791 -------------------------
3792 -- Formal_Is_Used_Once --
3793 -------------------------
3794
3795 function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is
3796 Use_Counter : Int := 0;
3797
3798 function Count_Uses (N : Node_Id) return Traverse_Result;
3799 -- Traverse the tree and count the uses of the formal parameter.
3800 -- In this case, for optimization purposes, we do not need to
3801 -- continue the traversal once more than one use is encountered.
3802
3803 ----------------
3804 -- Count_Uses --
3805 ----------------
3806
3807 function Count_Uses (N : Node_Id) return Traverse_Result is
3808 begin
3809 -- The original node is an identifier
3810
3811 if Nkind (N) = N_Identifier
3812 and then Present (Entity (N))
3813
3814 -- Original node's entity points to the one in the copied body
3815
3816 and then Nkind (Entity (N)) = N_Identifier
3817 and then Present (Entity (Entity (N)))
3818
3819 -- The entity of the copied node is the formal parameter
3820
3821 and then Entity (Entity (N)) = Formal
3822 then
3823 Use_Counter := Use_Counter + 1;
3824
3825 if Use_Counter > 1 then
3826
3827 -- Denote more than one use and abandon the traversal
3828
3829 Use_Counter := 2;
3830 return Abandon;
3831
3832 end if;
3833 end if;
3834
3835 return OK;
3836 end Count_Uses;
3837
3838 procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses);
3839
3840 -- Start of processing for Formal_Is_Used_Once
3841
3842 begin
3843 Count_Formal_Uses (Orig_Bod);
3844 return Use_Counter = 1;
3845 end Formal_Is_Used_Once;
3846
3847 -- Start of processing for Expand_Inlined_Call
3848
3849 begin
3850
3851 -- Check for an illegal attempt to inline a recursive procedure. If the
3852 -- subprogram has parameters this is detected when trying to supply a
3853 -- binding for parameters that already have one. For parameterless
3854 -- subprograms this must be done explicitly.
3855
3856 if In_Open_Scopes (Subp) then
3857 Error_Msg_N ("call to recursive subprogram cannot be inlined?", N);
3858 Set_Is_Inlined (Subp, False);
3859 return;
3860 end if;
3861
3862 if Nkind (Orig_Bod) = N_Defining_Identifier
3863 or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol
3864 then
3865 -- Subprogram is renaming_as_body. Calls occurring after the renaming
3866 -- can be replaced with calls to the renamed entity directly, because
3867 -- the subprograms are subtype conformant. If the renamed subprogram
3868 -- is an inherited operation, we must redo the expansion because
3869 -- implicit conversions may be needed. Similarly, if the renamed
3870 -- entity is inlined, expand the call for further optimizations.
3871
3872 Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc));
3873
3874 if Present (Alias (Orig_Bod)) or else Is_Inlined (Orig_Bod) then
3875 Expand_Call (N);
3876 end if;
3877
3878 return;
3879 end if;
3880
3881 -- Use generic machinery to copy body of inlined subprogram, as if it
3882 -- were an instantiation, resetting source locations appropriately, so
3883 -- that nested inlined calls appear in the main unit.
3884
3885 Save_Env (Subp, Empty);
3886 Set_Copied_Sloc_For_Inlined_Body (N, Defining_Entity (Orig_Bod));
3887
3888 Bod := Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True);
3889 Blk :=
3890 Make_Block_Statement (Loc,
3891 Declarations => Declarations (Bod),
3892 Handled_Statement_Sequence => Handled_Statement_Sequence (Bod));
3893
3894 if No (Declarations (Bod)) then
3895 Set_Declarations (Blk, New_List);
3896 end if;
3897
3898 -- For the unconstrained case, capture the name of the local
3899 -- variable that holds the result. This must be the first declaration
3900 -- in the block, because its bounds cannot depend on local variables.
3901 -- Otherwise there is no way to declare the result outside of the
3902 -- block. Needless to say, in general the bounds will depend on the
3903 -- actuals in the call.
3904
3905 if Is_Unc then
3906 Targ1 := Defining_Identifier (First (Declarations (Blk)));
3907 end if;
3908
3909 -- If this is a derived function, establish the proper return type
3910
3911 if Present (Orig_Subp)
3912 and then Orig_Subp /= Subp
3913 then
3914 Ret_Type := Etype (Orig_Subp);
3915 else
3916 Ret_Type := Etype (Subp);
3917 end if;
3918
3919 -- Create temporaries for the actuals that are expressions, or that
3920 -- are scalars and require copying to preserve semantics.
3921
3922 F := First_Formal (Subp);
3923 A := First_Actual (N);
3924 while Present (F) loop
3925 if Present (Renamed_Object (F)) then
3926 Error_Msg_N ("cannot inline call to recursive subprogram", N);
3927 return;
3928 end if;
3929
3930 -- If the argument may be a controlling argument in a call within
3931 -- the inlined body, we must preserve its classwide nature to insure
3932 -- that dynamic dispatching take place subsequently. If the formal
3933 -- has a constraint it must be preserved to retain the semantics of
3934 -- the body.
3935
3936 if Is_Class_Wide_Type (Etype (F))
3937 or else (Is_Access_Type (Etype (F))
3938 and then
3939 Is_Class_Wide_Type (Designated_Type (Etype (F))))
3940 then
3941 Temp_Typ := Etype (F);
3942
3943 elsif Base_Type (Etype (F)) = Base_Type (Etype (A))
3944 and then Etype (F) /= Base_Type (Etype (F))
3945 then
3946 Temp_Typ := Etype (F);
3947
3948 else
3949 Temp_Typ := Etype (A);
3950 end if;
3951
3952 -- If the actual is a simple name or a literal, no need to
3953 -- create a temporary, object can be used directly.
3954
3955 -- If the actual is a literal and the formal has its address taken,
3956 -- we cannot pass the literal itself as an argument, so its value
3957 -- must be captured in a temporary.
3958
3959 if (Is_Entity_Name (A)
3960 and then
3961 (not Is_Scalar_Type (Etype (A))
3962 or else Ekind (Entity (A)) = E_Enumeration_Literal))
3963
3964 -- When the actual is an identifier and the corresponding formal
3965 -- is used only once in the original body, the formal can be
3966 -- substituted directly with the actual parameter.
3967
3968 or else (Nkind (A) = N_Identifier
3969 and then Formal_Is_Used_Once (F))
3970
3971 or else
3972 (Nkind_In (A, N_Real_Literal,
3973 N_Integer_Literal,
3974 N_Character_Literal)
3975 and then not Address_Taken (F))
3976 then
3977 if Etype (F) /= Etype (A) then
3978 Set_Renamed_Object
3979 (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A)));
3980 else
3981 Set_Renamed_Object (F, A);
3982 end if;
3983
3984 else
3985 Temp := Make_Temporary (Loc, 'C');
3986
3987 -- If the actual for an in/in-out parameter is a view conversion,
3988 -- make it into an unchecked conversion, given that an untagged
3989 -- type conversion is not a proper object for a renaming.
3990
3991 -- In-out conversions that involve real conversions have already
3992 -- been transformed in Expand_Actuals.
3993
3994 if Nkind (A) = N_Type_Conversion
3995 and then Ekind (F) /= E_In_Parameter
3996 then
3997 New_A :=
3998 Make_Unchecked_Type_Conversion (Loc,
3999 Subtype_Mark => New_Occurrence_Of (Etype (F), Loc),
4000 Expression => Relocate_Node (Expression (A)));
4001
4002 elsif Etype (F) /= Etype (A) then
4003 New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A));
4004 Temp_Typ := Etype (F);
4005
4006 else
4007 New_A := Relocate_Node (A);
4008 end if;
4009
4010 Set_Sloc (New_A, Sloc (N));
4011
4012 -- If the actual has a by-reference type, it cannot be copied, so
4013 -- its value is captured in a renaming declaration. Otherwise
4014 -- declare a local constant initialized with the actual.
4015
4016 -- We also use a renaming declaration for expressions of an array
4017 -- type that is not bit-packed, both for efficiency reasons and to
4018 -- respect the semantics of the call: in most cases the original
4019 -- call will pass the parameter by reference, and thus the inlined
4020 -- code will have the same semantics.
4021
4022 if Ekind (F) = E_In_Parameter
4023 and then not Is_Limited_Type (Etype (A))
4024 and then not Is_Tagged_Type (Etype (A))
4025 and then
4026 (not Is_Array_Type (Etype (A))
4027 or else not Is_Object_Reference (A)
4028 or else Is_Bit_Packed_Array (Etype (A)))
4029 then
4030 Decl :=
4031 Make_Object_Declaration (Loc,
4032 Defining_Identifier => Temp,
4033 Constant_Present => True,
4034 Object_Definition => New_Occurrence_Of (Temp_Typ, Loc),
4035 Expression => New_A);
4036 else
4037 Decl :=
4038 Make_Object_Renaming_Declaration (Loc,
4039 Defining_Identifier => Temp,
4040 Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc),
4041 Name => New_A);
4042 end if;
4043
4044 Append (Decl, Decls);
4045 Set_Renamed_Object (F, Temp);
4046 end if;
4047
4048 Next_Formal (F);
4049 Next_Actual (A);
4050 end loop;
4051
4052 -- Establish target of function call. If context is not assignment or
4053 -- declaration, create a temporary as a target. The declaration for
4054 -- the temporary may be subsequently optimized away if the body is a
4055 -- single expression, or if the left-hand side of the assignment is
4056 -- simple enough, i.e. an entity or an explicit dereference of one.
4057
4058 if Ekind (Subp) = E_Function then
4059 if Nkind (Parent (N)) = N_Assignment_Statement
4060 and then Is_Entity_Name (Name (Parent (N)))
4061 then
4062 Targ := Name (Parent (N));
4063
4064 elsif Nkind (Parent (N)) = N_Assignment_Statement
4065 and then Nkind (Name (Parent (N))) = N_Explicit_Dereference
4066 and then Is_Entity_Name (Prefix (Name (Parent (N))))
4067 then
4068 Targ := Name (Parent (N));
4069
4070 elsif Nkind (Parent (N)) = N_Object_Declaration
4071 and then Is_Limited_Type (Etype (Subp))
4072 then
4073 Targ := Defining_Identifier (Parent (N));
4074
4075 else
4076 -- Replace call with temporary and create its declaration
4077
4078 Temp := Make_Temporary (Loc, 'C');
4079 Set_Is_Internal (Temp);
4080
4081 -- For the unconstrained case, the generated temporary has the
4082 -- same constrained declaration as the result variable. It may
4083 -- eventually be possible to remove that temporary and use the
4084 -- result variable directly.
4085
4086 if Is_Unc then
4087 Decl :=
4088 Make_Object_Declaration (Loc,
4089 Defining_Identifier => Temp,
4090 Object_Definition =>
4091 New_Copy_Tree (Object_Definition (Parent (Targ1))));
4092
4093 Replace_Formals (Decl);
4094
4095 else
4096 Decl :=
4097 Make_Object_Declaration (Loc,
4098 Defining_Identifier => Temp,
4099 Object_Definition =>
4100 New_Occurrence_Of (Ret_Type, Loc));
4101
4102 Set_Etype (Temp, Ret_Type);
4103 end if;
4104
4105 Set_No_Initialization (Decl);
4106 Append (Decl, Decls);
4107 Rewrite (N, New_Occurrence_Of (Temp, Loc));
4108 Targ := Temp;
4109 end if;
4110 end if;
4111
4112 Insert_Actions (N, Decls);
4113
4114 -- Traverse the tree and replace formals with actuals or their thunks.
4115 -- Attach block to tree before analysis and rewriting.
4116
4117 Replace_Formals (Blk);
4118 Set_Parent (Blk, N);
4119
4120 if not Comes_From_Source (Subp)
4121 or else Is_Predef
4122 then
4123 Reset_Slocs (Blk);
4124 end if;
4125
4126 if Present (Exit_Lab) then
4127
4128 -- If the body was a single expression, the single return statement
4129 -- and the corresponding label are useless.
4130
4131 if Num_Ret = 1
4132 and then
4133 Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) =
4134 N_Goto_Statement
4135 then
4136 Remove (Last (Statements (Handled_Statement_Sequence (Blk))));
4137 else
4138 Append (Lab_Decl, (Declarations (Blk)));
4139 Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk)));
4140 end if;
4141 end if;
4142
4143 -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on
4144 -- conflicting private views that Gigi would ignore. If this is a
4145 -- predefined unit, analyze with checks off, as is done in the non-
4146 -- inlined run-time units.
4147
4148 declare
4149 I_Flag : constant Boolean := In_Inlined_Body;
4150
4151 begin
4152 In_Inlined_Body := True;
4153
4154 if Is_Predef then
4155 declare
4156 Style : constant Boolean := Style_Check;
4157 begin
4158 Style_Check := False;
4159 Analyze (Blk, Suppress => All_Checks);
4160 Style_Check := Style;
4161 end;
4162
4163 else
4164 Analyze (Blk);
4165 end if;
4166
4167 In_Inlined_Body := I_Flag;
4168 end;
4169
4170 if Ekind (Subp) = E_Procedure then
4171 Rewrite_Procedure_Call (N, Blk);
4172 else
4173 Rewrite_Function_Call (N, Blk);
4174
4175 -- For the unconstrained case, the replacement of the call has been
4176 -- made prior to the complete analysis of the generated declarations.
4177 -- Propagate the proper type now.
4178
4179 if Is_Unc then
4180 if Nkind (N) = N_Identifier then
4181 Set_Etype (N, Etype (Entity (N)));
4182 else
4183 Set_Etype (N, Etype (Targ1));
4184 end if;
4185 end if;
4186 end if;
4187
4188 Restore_Env;
4189
4190 -- Cleanup mapping between formals and actuals for other expansions
4191
4192 F := First_Formal (Subp);
4193 while Present (F) loop
4194 Set_Renamed_Object (F, Empty);
4195 Next_Formal (F);
4196 end loop;
4197 end Expand_Inlined_Call;
4198
4199 ----------------------------------------
4200 -- Expand_N_Extended_Return_Statement --
4201 ----------------------------------------
4202
4203 -- If there is a Handled_Statement_Sequence, we rewrite this:
4204
4205 -- return Result : T := <expression> do
4206 -- <handled_seq_of_stms>
4207 -- end return;
4208
4209 -- to be:
4210
4211 -- declare
4212 -- Result : T := <expression>;
4213 -- begin
4214 -- <handled_seq_of_stms>
4215 -- return Result;
4216 -- end;
4217
4218 -- Otherwise (no Handled_Statement_Sequence), we rewrite this:
4219
4220 -- return Result : T := <expression>;
4221
4222 -- to be:
4223
4224 -- return <expression>;
4225
4226 -- unless it's build-in-place or there's no <expression>, in which case
4227 -- we generate:
4228
4229 -- declare
4230 -- Result : T := <expression>;
4231 -- begin
4232 -- return Result;
4233 -- end;
4234
4235 -- Note that this case could have been written by the user as an extended
4236 -- return statement, or could have been transformed to this from a simple
4237 -- return statement.
4238
4239 -- That is, we need to have a reified return object if there are statements
4240 -- (which might refer to it) or if we're doing build-in-place (so we can
4241 -- set its address to the final resting place or if there is no expression
4242 -- (in which case default initial values might need to be set).
4243
4244 procedure Expand_N_Extended_Return_Statement (N : Node_Id) is
4245 Loc : constant Source_Ptr := Sloc (N);
4246
4247 Return_Object_Entity : constant Entity_Id :=
4248 First_Entity (Return_Statement_Entity (N));
4249 Return_Object_Decl : constant Node_Id :=
4250 Parent (Return_Object_Entity);
4251 Parent_Function : constant Entity_Id :=
4252 Return_Applies_To (Return_Statement_Entity (N));
4253 Parent_Function_Typ : constant Entity_Id := Etype (Parent_Function);
4254 Is_Build_In_Place : constant Boolean :=
4255 Is_Build_In_Place_Function (Parent_Function);
4256
4257 Return_Stm : Node_Id;
4258 Statements : List_Id;
4259 Handled_Stm_Seq : Node_Id;
4260 Result : Node_Id;
4261 Exp : Node_Id;
4262
4263 function Has_Controlled_Parts (Typ : Entity_Id) return Boolean;
4264 -- Determine whether type Typ is controlled or contains a controlled
4265 -- subcomponent.
4266
4267 function Move_Activation_Chain return Node_Id;
4268 -- Construct a call to System.Tasking.Stages.Move_Activation_Chain
4269 -- with parameters:
4270 -- From current activation chain
4271 -- To activation chain passed in by the caller
4272 -- New_Master master passed in by the caller
4273
4274 function Move_Final_List return Node_Id;
4275 -- Construct call to System.Finalization_Implementation.Move_Final_List
4276 -- with parameters:
4277 --
4278 -- From finalization list of the return statement
4279 -- To finalization list passed in by the caller
4280
4281 --------------------------
4282 -- Has_Controlled_Parts --
4283 --------------------------
4284
4285 function Has_Controlled_Parts (Typ : Entity_Id) return Boolean is
4286 begin
4287 return
4288 Is_Controlled (Typ)
4289 or else Has_Controlled_Component (Typ);
4290 end Has_Controlled_Parts;
4291
4292 ---------------------------
4293 -- Move_Activation_Chain --
4294 ---------------------------
4295
4296 function Move_Activation_Chain return Node_Id is
4297 Activation_Chain_Formal : constant Entity_Id :=
4298 Build_In_Place_Formal
4299 (Parent_Function, BIP_Activation_Chain);
4300 To : constant Node_Id :=
4301 New_Reference_To
4302 (Activation_Chain_Formal, Loc);
4303 Master_Formal : constant Entity_Id :=
4304 Build_In_Place_Formal
4305 (Parent_Function, BIP_Master);
4306 New_Master : constant Node_Id :=
4307 New_Reference_To (Master_Formal, Loc);
4308
4309 Chain_Entity : Entity_Id;
4310 From : Node_Id;
4311
4312 begin
4313 Chain_Entity := First_Entity (Return_Statement_Entity (N));
4314 while Chars (Chain_Entity) /= Name_uChain loop
4315 Chain_Entity := Next_Entity (Chain_Entity);
4316 end loop;
4317
4318 From :=
4319 Make_Attribute_Reference (Loc,
4320 Prefix => New_Reference_To (Chain_Entity, Loc),
4321 Attribute_Name => Name_Unrestricted_Access);
4322 -- ??? Not clear why "Make_Identifier (Loc, Name_uChain)" doesn't
4323 -- work, instead of "New_Reference_To (Chain_Entity, Loc)" above.
4324
4325 return
4326 Make_Procedure_Call_Statement (Loc,
4327 Name => New_Reference_To (RTE (RE_Move_Activation_Chain), Loc),
4328 Parameter_Associations => New_List (From, To, New_Master));
4329 end Move_Activation_Chain;
4330
4331 ---------------------
4332 -- Move_Final_List --
4333 ---------------------
4334
4335 function Move_Final_List return Node_Id is
4336 Flist : constant Entity_Id :=
4337 Finalization_Chain_Entity (Return_Statement_Entity (N));
4338
4339 From : constant Node_Id := New_Reference_To (Flist, Loc);
4340
4341 Caller_Final_List : constant Entity_Id :=
4342 Build_In_Place_Formal
4343 (Parent_Function, BIP_Final_List);
4344
4345 To : constant Node_Id := New_Reference_To (Caller_Final_List, Loc);
4346
4347 begin
4348 -- Catch cases where a finalization chain entity has not been
4349 -- associated with the return statement entity.
4350
4351 pragma Assert (Present (Flist));
4352
4353 -- Build required call
4354
4355 return
4356 Make_If_Statement (Loc,
4357 Condition =>
4358 Make_Op_Ne (Loc,
4359 Left_Opnd => New_Copy (From),
4360 Right_Opnd => New_Node (N_Null, Loc)),
4361 Then_Statements =>
4362 New_List (
4363 Make_Procedure_Call_Statement (Loc,
4364 Name => New_Reference_To (RTE (RE_Move_Final_List), Loc),
4365 Parameter_Associations => New_List (From, To))));
4366 end Move_Final_List;
4367
4368 -- Start of processing for Expand_N_Extended_Return_Statement
4369
4370 begin
4371 if Nkind (Return_Object_Decl) = N_Object_Declaration then
4372 Exp := Expression (Return_Object_Decl);
4373 else
4374 Exp := Empty;
4375 end if;
4376
4377 Handled_Stm_Seq := Handled_Statement_Sequence (N);
4378
4379 -- Build a simple_return_statement that returns the return object when
4380 -- there is a statement sequence, or no expression, or the result will
4381 -- be built in place. Note however that we currently do this for all
4382 -- composite cases, even though nonlimited composite results are not yet
4383 -- built in place (though we plan to do so eventually).
4384
4385 if Present (Handled_Stm_Seq)
4386 or else Is_Composite_Type (Etype (Parent_Function))
4387 or else No (Exp)
4388 then
4389 if No (Handled_Stm_Seq) then
4390 Statements := New_List;
4391
4392 -- If the extended return has a handled statement sequence, then wrap
4393 -- it in a block and use the block as the first statement.
4394
4395 else
4396 Statements :=
4397 New_List (Make_Block_Statement (Loc,
4398 Declarations => New_List,
4399 Handled_Statement_Sequence => Handled_Stm_Seq));
4400 end if;
4401
4402 -- If control gets past the above Statements, we have successfully
4403 -- completed the return statement. If the result type has controlled
4404 -- parts and the return is for a build-in-place function, then we
4405 -- call Move_Final_List to transfer responsibility for finalization
4406 -- of the return object to the caller. An alternative would be to
4407 -- declare a Success flag in the function, initialize it to False,
4408 -- and set it to True here. Then move the Move_Final_List call into
4409 -- the cleanup code, and check Success. If Success then make a call
4410 -- to Move_Final_List else do finalization. Then we can remove the
4411 -- abort-deferral and the nulling-out of the From parameter from
4412 -- Move_Final_List. Note that the current method is not quite correct
4413 -- in the rather obscure case of a select-then-abort statement whose
4414 -- abortable part contains the return statement.
4415
4416 -- Check the type of the function to determine whether to move the
4417 -- finalization list. A special case arises when processing a simple
4418 -- return statement which has been rewritten as an extended return.
4419 -- In that case check the type of the returned object or the original
4420 -- expression.
4421
4422 if Is_Build_In_Place
4423 and then
4424 (Has_Controlled_Parts (Parent_Function_Typ)
4425 or else (Is_Class_Wide_Type (Parent_Function_Typ)
4426 and then
4427 Has_Controlled_Parts (Root_Type (Parent_Function_Typ)))
4428 or else Has_Controlled_Parts (Etype (Return_Object_Entity))
4429 or else (Present (Exp)
4430 and then Has_Controlled_Parts (Etype (Exp))))
4431 then
4432 Append_To (Statements, Move_Final_List);
4433 end if;
4434
4435 -- Similarly to the above Move_Final_List, if the result type
4436 -- contains tasks, we call Move_Activation_Chain. Later, the cleanup
4437 -- code will call Complete_Master, which will terminate any
4438 -- unactivated tasks belonging to the return statement master. But
4439 -- Move_Activation_Chain updates their master to be that of the
4440 -- caller, so they will not be terminated unless the return statement
4441 -- completes unsuccessfully due to exception, abort, goto, or exit.
4442 -- As a formality, we test whether the function requires the result
4443 -- to be built in place, though that's necessarily true for the case
4444 -- of result types with task parts.
4445
4446 if Is_Build_In_Place and Has_Task (Etype (Parent_Function)) then
4447 Append_To (Statements, Move_Activation_Chain);
4448 end if;
4449
4450 -- Build a simple_return_statement that returns the return object
4451
4452 Return_Stm :=
4453 Make_Simple_Return_Statement (Loc,
4454 Expression => New_Occurrence_Of (Return_Object_Entity, Loc));
4455 Append_To (Statements, Return_Stm);
4456
4457 Handled_Stm_Seq :=
4458 Make_Handled_Sequence_Of_Statements (Loc, Statements);
4459 end if;
4460
4461 -- Case where we build a block
4462
4463 if Present (Handled_Stm_Seq) then
4464 Result :=
4465 Make_Block_Statement (Loc,
4466 Declarations => Return_Object_Declarations (N),
4467 Handled_Statement_Sequence => Handled_Stm_Seq);
4468
4469 -- We set the entity of the new block statement to be that of the
4470 -- return statement. This is necessary so that various fields, such
4471 -- as Finalization_Chain_Entity carry over from the return statement
4472 -- to the block. Note that this block is unusual, in that its entity
4473 -- is an E_Return_Statement rather than an E_Block.
4474
4475 Set_Identifier
4476 (Result, New_Occurrence_Of (Return_Statement_Entity (N), Loc));
4477
4478 -- If the object decl was already rewritten as a renaming, then
4479 -- we don't want to do the object allocation and transformation of
4480 -- of the return object declaration to a renaming. This case occurs
4481 -- when the return object is initialized by a call to another
4482 -- build-in-place function, and that function is responsible for the
4483 -- allocation of the return object.
4484
4485 if Is_Build_In_Place
4486 and then
4487 Nkind (Return_Object_Decl) = N_Object_Renaming_Declaration
4488 then
4489 pragma Assert (Nkind (Original_Node (Return_Object_Decl)) =
4490 N_Object_Declaration
4491 and then Is_Build_In_Place_Function_Call
4492 (Expression (Original_Node (Return_Object_Decl))));
4493
4494 Set_By_Ref (Return_Stm); -- Return build-in-place results by ref
4495
4496 elsif Is_Build_In_Place then
4497
4498 -- Locate the implicit access parameter associated with the
4499 -- caller-supplied return object and convert the return
4500 -- statement's return object declaration to a renaming of a
4501 -- dereference of the access parameter. If the return object's
4502 -- declaration includes an expression that has not already been
4503 -- expanded as separate assignments, then add an assignment
4504 -- statement to ensure the return object gets initialized.
4505
4506 -- declare
4507 -- Result : T [:= <expression>];
4508 -- begin
4509 -- ...
4510
4511 -- is converted to
4512
4513 -- declare
4514 -- Result : T renames FuncRA.all;
4515 -- [Result := <expression;]
4516 -- begin
4517 -- ...
4518
4519 declare
4520 Return_Obj_Id : constant Entity_Id :=
4521 Defining_Identifier (Return_Object_Decl);
4522 Return_Obj_Typ : constant Entity_Id := Etype (Return_Obj_Id);
4523 Return_Obj_Expr : constant Node_Id :=
4524 Expression (Return_Object_Decl);
4525 Result_Subt : constant Entity_Id :=
4526 Etype (Parent_Function);
4527 Constr_Result : constant Boolean :=
4528 Is_Constrained (Result_Subt);
4529 Obj_Alloc_Formal : Entity_Id;
4530 Object_Access : Entity_Id;
4531 Obj_Acc_Deref : Node_Id;
4532 Init_Assignment : Node_Id := Empty;
4533
4534 begin
4535 -- Build-in-place results must be returned by reference
4536
4537 Set_By_Ref (Return_Stm);
4538
4539 -- Retrieve the implicit access parameter passed by the caller
4540
4541 Object_Access :=
4542 Build_In_Place_Formal (Parent_Function, BIP_Object_Access);
4543
4544 -- If the return object's declaration includes an expression
4545 -- and the declaration isn't marked as No_Initialization, then
4546 -- we need to generate an assignment to the object and insert
4547 -- it after the declaration before rewriting it as a renaming
4548 -- (otherwise we'll lose the initialization). The case where
4549 -- the result type is an interface (or class-wide interface)
4550 -- is also excluded because the context of the function call
4551 -- must be unconstrained, so the initialization will always
4552 -- be done as part of an allocator evaluation (storage pool
4553 -- or secondary stack), never to a constrained target object
4554 -- passed in by the caller. Besides the assignment being
4555 -- unneeded in this case, it avoids problems with trying to
4556 -- generate a dispatching assignment when the return expression
4557 -- is a nonlimited descendant of a limited interface (the
4558 -- interface has no assignment operation).
4559
4560 if Present (Return_Obj_Expr)
4561 and then not No_Initialization (Return_Object_Decl)
4562 and then not Is_Interface (Return_Obj_Typ)
4563 then
4564 Init_Assignment :=
4565 Make_Assignment_Statement (Loc,
4566 Name => New_Reference_To (Return_Obj_Id, Loc),
4567 Expression => Relocate_Node (Return_Obj_Expr));
4568 Set_Etype (Name (Init_Assignment), Etype (Return_Obj_Id));
4569 Set_Assignment_OK (Name (Init_Assignment));
4570 Set_No_Ctrl_Actions (Init_Assignment);
4571
4572 Set_Parent (Name (Init_Assignment), Init_Assignment);
4573 Set_Parent (Expression (Init_Assignment), Init_Assignment);
4574
4575 Set_Expression (Return_Object_Decl, Empty);
4576
4577 if Is_Class_Wide_Type (Etype (Return_Obj_Id))
4578 and then not Is_Class_Wide_Type
4579 (Etype (Expression (Init_Assignment)))
4580 then
4581 Rewrite (Expression (Init_Assignment),
4582 Make_Type_Conversion (Loc,
4583 Subtype_Mark =>
4584 New_Occurrence_Of
4585 (Etype (Return_Obj_Id), Loc),
4586 Expression =>
4587 Relocate_Node (Expression (Init_Assignment))));
4588 end if;
4589
4590 -- In the case of functions where the calling context can
4591 -- determine the form of allocation needed, initialization
4592 -- is done with each part of the if statement that handles
4593 -- the different forms of allocation (this is true for
4594 -- unconstrained and tagged result subtypes).
4595
4596 if Constr_Result
4597 and then not Is_Tagged_Type (Underlying_Type (Result_Subt))
4598 then
4599 Insert_After (Return_Object_Decl, Init_Assignment);
4600 end if;
4601 end if;
4602
4603 -- When the function's subtype is unconstrained, a run-time
4604 -- test is needed to determine the form of allocation to use
4605 -- for the return object. The function has an implicit formal
4606 -- parameter indicating this. If the BIP_Alloc_Form formal has
4607 -- the value one, then the caller has passed access to an
4608 -- existing object for use as the return object. If the value
4609 -- is two, then the return object must be allocated on the
4610 -- secondary stack. Otherwise, the object must be allocated in
4611 -- a storage pool (currently only supported for the global
4612 -- heap, user-defined storage pools TBD ???). We generate an
4613 -- if statement to test the implicit allocation formal and
4614 -- initialize a local access value appropriately, creating
4615 -- allocators in the secondary stack and global heap cases.
4616 -- The special formal also exists and must be tested when the
4617 -- function has a tagged result, even when the result subtype
4618 -- is constrained, because in general such functions can be
4619 -- called in dispatching contexts and must be handled similarly
4620 -- to functions with a class-wide result.
4621
4622 if not Constr_Result
4623 or else Is_Tagged_Type (Underlying_Type (Result_Subt))
4624 then
4625 Obj_Alloc_Formal :=
4626 Build_In_Place_Formal (Parent_Function, BIP_Alloc_Form);
4627
4628 declare
4629 Ref_Type : Entity_Id;
4630 Ptr_Type_Decl : Node_Id;
4631 Alloc_Obj_Id : Entity_Id;
4632 Alloc_Obj_Decl : Node_Id;
4633 Alloc_If_Stmt : Node_Id;
4634 SS_Allocator : Node_Id;
4635 Heap_Allocator : Node_Id;
4636
4637 begin
4638 -- Reuse the itype created for the function's implicit
4639 -- access formal. This avoids the need to create a new
4640 -- access type here, plus it allows assigning the access
4641 -- formal directly without applying a conversion.
4642
4643 -- Ref_Type := Etype (Object_Access);
4644
4645 -- Create an access type designating the function's
4646 -- result subtype.
4647
4648 Ref_Type := Make_Temporary (Loc, 'A');
4649
4650 Ptr_Type_Decl :=
4651 Make_Full_Type_Declaration (Loc,
4652 Defining_Identifier => Ref_Type,
4653 Type_Definition =>
4654 Make_Access_To_Object_Definition (Loc,
4655 All_Present => True,
4656 Subtype_Indication =>
4657 New_Reference_To (Return_Obj_Typ, Loc)));
4658
4659 Insert_Before (Return_Object_Decl, Ptr_Type_Decl);
4660
4661 -- Create an access object that will be initialized to an
4662 -- access value denoting the return object, either coming
4663 -- from an implicit access value passed in by the caller
4664 -- or from the result of an allocator.
4665
4666 Alloc_Obj_Id := Make_Temporary (Loc, 'R');
4667 Set_Etype (Alloc_Obj_Id, Ref_Type);
4668
4669 Alloc_Obj_Decl :=
4670 Make_Object_Declaration (Loc,
4671 Defining_Identifier => Alloc_Obj_Id,
4672 Object_Definition => New_Reference_To
4673 (Ref_Type, Loc));
4674
4675 Insert_Before (Return_Object_Decl, Alloc_Obj_Decl);
4676
4677 -- Create allocators for both the secondary stack and
4678 -- global heap. If there's an initialization expression,
4679 -- then create these as initialized allocators.
4680
4681 if Present (Return_Obj_Expr)
4682 and then not No_Initialization (Return_Object_Decl)
4683 then
4684 -- Always use the type of the expression for the
4685 -- qualified expression, rather than the result type.
4686 -- In general we cannot always use the result type
4687 -- for the allocator, because the expression might be
4688 -- of a specific type, such as in the case of an
4689 -- aggregate or even a nonlimited object when the
4690 -- result type is a limited class-wide interface type.
4691
4692 Heap_Allocator :=
4693 Make_Allocator (Loc,
4694 Expression =>
4695 Make_Qualified_Expression (Loc,
4696 Subtype_Mark =>
4697 New_Reference_To
4698 (Etype (Return_Obj_Expr), Loc),
4699 Expression =>
4700 New_Copy_Tree (Return_Obj_Expr)));
4701
4702 else
4703 -- If the function returns a class-wide type we cannot
4704 -- use the return type for the allocator. Instead we
4705 -- use the type of the expression, which must be an
4706 -- aggregate of a definite type.
4707
4708 if Is_Class_Wide_Type (Return_Obj_Typ) then
4709 Heap_Allocator :=
4710 Make_Allocator (Loc,
4711 Expression =>
4712 New_Reference_To
4713 (Etype (Return_Obj_Expr), Loc));
4714 else
4715 Heap_Allocator :=
4716 Make_Allocator (Loc,
4717 Expression =>
4718 New_Reference_To (Return_Obj_Typ, Loc));
4719 end if;
4720
4721 -- If the object requires default initialization then
4722 -- that will happen later following the elaboration of
4723 -- the object renaming. If we don't turn it off here
4724 -- then the object will be default initialized twice.
4725
4726 Set_No_Initialization (Heap_Allocator);
4727 end if;
4728
4729 -- If the No_Allocators restriction is active, then only
4730 -- an allocator for secondary stack allocation is needed.
4731 -- It's OK for such allocators to have Comes_From_Source
4732 -- set to False, because gigi knows not to flag them as
4733 -- being a violation of No_Implicit_Heap_Allocations.
4734
4735 if Restriction_Active (No_Allocators) then
4736 SS_Allocator := Heap_Allocator;
4737 Heap_Allocator := Make_Null (Loc);
4738
4739 -- Otherwise the heap allocator may be needed, so we make
4740 -- another allocator for secondary stack allocation.
4741
4742 else
4743 SS_Allocator := New_Copy_Tree (Heap_Allocator);
4744
4745 -- The heap allocator is marked Comes_From_Source
4746 -- since it corresponds to an explicit user-written
4747 -- allocator (that is, it will only be executed on
4748 -- behalf of callers that call the function as
4749 -- initialization for such an allocator). This
4750 -- prevents errors when No_Implicit_Heap_Allocations
4751 -- is in force.
4752
4753 Set_Comes_From_Source (Heap_Allocator, True);
4754 end if;
4755
4756 -- The allocator is returned on the secondary stack. We
4757 -- don't do this on VM targets, since the SS is not used.
4758
4759 if VM_Target = No_VM then
4760 Set_Storage_Pool (SS_Allocator, RTE (RE_SS_Pool));
4761 Set_Procedure_To_Call
4762 (SS_Allocator, RTE (RE_SS_Allocate));
4763
4764 -- The allocator is returned on the secondary stack,
4765 -- so indicate that the function return, as well as
4766 -- the block that encloses the allocator, must not
4767 -- release it. The flags must be set now because the
4768 -- decision to use the secondary stack is done very
4769 -- late in the course of expanding the return
4770 -- statement, past the point where these flags are
4771 -- normally set.
4772
4773 Set_Sec_Stack_Needed_For_Return (Parent_Function);
4774 Set_Sec_Stack_Needed_For_Return
4775 (Return_Statement_Entity (N));
4776 Set_Uses_Sec_Stack (Parent_Function);
4777 Set_Uses_Sec_Stack (Return_Statement_Entity (N));
4778 end if;
4779
4780 -- Create an if statement to test the BIP_Alloc_Form
4781 -- formal and initialize the access object to either the
4782 -- BIP_Object_Access formal (BIP_Alloc_Form = 0), the
4783 -- result of allocating the object in the secondary stack
4784 -- (BIP_Alloc_Form = 1), or else an allocator to create
4785 -- the return object in the heap (BIP_Alloc_Form = 2).
4786
4787 -- ??? An unchecked type conversion must be made in the
4788 -- case of assigning the access object formal to the
4789 -- local access object, because a normal conversion would
4790 -- be illegal in some cases (such as converting access-
4791 -- to-unconstrained to access-to-constrained), but the
4792 -- the unchecked conversion will presumably fail to work
4793 -- right in just such cases. It's not clear at all how to
4794 -- handle this. ???
4795
4796 Alloc_If_Stmt :=
4797 Make_If_Statement (Loc,
4798 Condition =>
4799 Make_Op_Eq (Loc,
4800 Left_Opnd =>
4801 New_Reference_To (Obj_Alloc_Formal, Loc),
4802 Right_Opnd =>
4803 Make_Integer_Literal (Loc,
4804 UI_From_Int (BIP_Allocation_Form'Pos
4805 (Caller_Allocation)))),
4806 Then_Statements =>
4807 New_List (Make_Assignment_Statement (Loc,
4808 Name =>
4809 New_Reference_To
4810 (Alloc_Obj_Id, Loc),
4811 Expression =>
4812 Make_Unchecked_Type_Conversion (Loc,
4813 Subtype_Mark =>
4814 New_Reference_To (Ref_Type, Loc),
4815 Expression =>
4816 New_Reference_To
4817 (Object_Access, Loc)))),
4818 Elsif_Parts =>
4819 New_List (Make_Elsif_Part (Loc,
4820 Condition =>
4821 Make_Op_Eq (Loc,
4822 Left_Opnd =>
4823 New_Reference_To
4824 (Obj_Alloc_Formal, Loc),
4825 Right_Opnd =>
4826 Make_Integer_Literal (Loc,
4827 UI_From_Int (
4828 BIP_Allocation_Form'Pos
4829 (Secondary_Stack)))),
4830 Then_Statements =>
4831 New_List
4832 (Make_Assignment_Statement (Loc,
4833 Name =>
4834 New_Reference_To
4835 (Alloc_Obj_Id, Loc),
4836 Expression =>
4837 SS_Allocator)))),
4838 Else_Statements =>
4839 New_List (Make_Assignment_Statement (Loc,
4840 Name =>
4841 New_Reference_To
4842 (Alloc_Obj_Id, Loc),
4843 Expression =>
4844 Heap_Allocator)));
4845
4846 -- If a separate initialization assignment was created
4847 -- earlier, append that following the assignment of the
4848 -- implicit access formal to the access object, to ensure
4849 -- that the return object is initialized in that case.
4850 -- In this situation, the target of the assignment must
4851 -- be rewritten to denote a dereference of the access to
4852 -- the return object passed in by the caller.
4853
4854 if Present (Init_Assignment) then
4855 Rewrite (Name (Init_Assignment),
4856 Make_Explicit_Dereference (Loc,
4857 Prefix => New_Reference_To (Alloc_Obj_Id, Loc)));
4858 Set_Etype
4859 (Name (Init_Assignment), Etype (Return_Obj_Id));
4860
4861 Append_To
4862 (Then_Statements (Alloc_If_Stmt),
4863 Init_Assignment);
4864 end if;
4865
4866 Insert_Before (Return_Object_Decl, Alloc_If_Stmt);
4867
4868 -- Remember the local access object for use in the
4869 -- dereference of the renaming created below.
4870
4871 Object_Access := Alloc_Obj_Id;
4872 end;
4873 end if;
4874
4875 -- Replace the return object declaration with a renaming of a
4876 -- dereference of the access value designating the return
4877 -- object.
4878
4879 Obj_Acc_Deref :=
4880 Make_Explicit_Dereference (Loc,
4881 Prefix => New_Reference_To (Object_Access, Loc));
4882
4883 Rewrite (Return_Object_Decl,
4884 Make_Object_Renaming_Declaration (Loc,
4885 Defining_Identifier => Return_Obj_Id,
4886 Access_Definition => Empty,
4887 Subtype_Mark => New_Occurrence_Of
4888 (Return_Obj_Typ, Loc),
4889 Name => Obj_Acc_Deref));
4890
4891 Set_Renamed_Object (Return_Obj_Id, Obj_Acc_Deref);
4892 end;
4893 end if;
4894
4895 -- Case where we do not build a block
4896
4897 else
4898 -- We're about to drop Return_Object_Declarations on the floor, so
4899 -- we need to insert it, in case it got expanded into useful code.
4900 -- Remove side effects from expression, which may be duplicated in
4901 -- subsequent checks (see Expand_Simple_Function_Return).
4902
4903 Insert_List_Before (N, Return_Object_Declarations (N));
4904 Remove_Side_Effects (Exp);
4905
4906 -- Build simple_return_statement that returns the expression directly
4907
4908 Return_Stm := Make_Simple_Return_Statement (Loc, Expression => Exp);
4909
4910 Result := Return_Stm;
4911 end if;
4912
4913 -- Set the flag to prevent infinite recursion
4914
4915 Set_Comes_From_Extended_Return_Statement (Return_Stm);
4916
4917 Rewrite (N, Result);
4918 Analyze (N);
4919 end Expand_N_Extended_Return_Statement;
4920
4921 ----------------------------
4922 -- Expand_N_Function_Call --
4923 ----------------------------
4924
4925 procedure Expand_N_Function_Call (N : Node_Id) is
4926 begin
4927 Expand_Call (N);
4928
4929 -- If the return value of a foreign compiled function is VAX Float, then
4930 -- expand the return (adjusts the location of the return value on
4931 -- Alpha/VMS, no-op everywhere else).
4932 -- Comes_From_Source intercepts recursive expansion.
4933
4934 if Vax_Float (Etype (N))
4935 and then Nkind (N) = N_Function_Call
4936 and then Present (Name (N))
4937 and then Present (Entity (Name (N)))
4938 and then Has_Foreign_Convention (Entity (Name (N)))
4939 and then Comes_From_Source (Parent (N))
4940 then
4941 Expand_Vax_Foreign_Return (N);
4942 end if;
4943 end Expand_N_Function_Call;
4944
4945 ---------------------------------------
4946 -- Expand_N_Procedure_Call_Statement --
4947 ---------------------------------------
4948
4949 procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is
4950 begin
4951 Expand_Call (N);
4952 end Expand_N_Procedure_Call_Statement;
4953
4954 --------------------------------------
4955 -- Expand_N_Simple_Return_Statement --
4956 --------------------------------------
4957
4958 procedure Expand_N_Simple_Return_Statement (N : Node_Id) is
4959 begin
4960 -- Defend against previous errors (i.e. the return statement calls a
4961 -- function that is not available in configurable runtime).
4962
4963 if Present (Expression (N))
4964 and then Nkind (Expression (N)) = N_Empty
4965 then
4966 return;
4967 end if;
4968
4969 -- Distinguish the function and non-function cases:
4970
4971 case Ekind (Return_Applies_To (Return_Statement_Entity (N))) is
4972
4973 when E_Function |
4974 E_Generic_Function =>
4975 Expand_Simple_Function_Return (N);
4976
4977 when E_Procedure |
4978 E_Generic_Procedure |
4979 E_Entry |
4980 E_Entry_Family |
4981 E_Return_Statement =>
4982 Expand_Non_Function_Return (N);
4983
4984 when others =>
4985 raise Program_Error;
4986 end case;
4987
4988 exception
4989 when RE_Not_Available =>
4990 return;
4991 end Expand_N_Simple_Return_Statement;
4992
4993 ------------------------------
4994 -- Expand_N_Subprogram_Body --
4995 ------------------------------
4996
4997 -- Add poll call if ATC polling is enabled, unless the body will be inlined
4998 -- by the back-end.
4999
5000 -- Add dummy push/pop label nodes at start and end to clear any local
5001 -- exception indications if local-exception-to-goto optimization is active.
5002
5003 -- Add return statement if last statement in body is not a return statement
5004 -- (this makes things easier on Gigi which does not want to have to handle
5005 -- a missing return).
5006
5007 -- Add call to Activate_Tasks if body is a task activator
5008
5009 -- Deal with possible detection of infinite recursion
5010
5011 -- Eliminate body completely if convention stubbed
5012
5013 -- Encode entity names within body, since we will not need to reference
5014 -- these entities any longer in the front end.
5015
5016 -- Initialize scalar out parameters if Initialize/Normalize_Scalars
5017
5018 -- Reset Pure indication if any parameter has root type System.Address
5019 -- or has any parameters of limited types, where limited means that the
5020 -- run-time view is limited (i.e. the full type is limited).
5021
5022 -- Wrap thread body
5023
5024 procedure Expand_N_Subprogram_Body (N : Node_Id) is
5025 Loc : constant Source_Ptr := Sloc (N);
5026 H : constant Node_Id := Handled_Statement_Sequence (N);
5027 Body_Id : Entity_Id;
5028 Except_H : Node_Id;
5029 L : List_Id;
5030 Spec_Id : Entity_Id;
5031
5032 procedure Add_Return (S : List_Id);
5033 -- Append a return statement to the statement sequence S if the last
5034 -- statement is not already a return or a goto statement. Note that
5035 -- the latter test is not critical, it does not matter if we add a few
5036 -- extra returns, since they get eliminated anyway later on.
5037
5038 ----------------
5039 -- Add_Return --
5040 ----------------
5041
5042 procedure Add_Return (S : List_Id) is
5043 Last_Stm : Node_Id;
5044 Loc : Source_Ptr;
5045
5046 begin
5047 -- Get last statement, ignoring any Pop_xxx_Label nodes, which are
5048 -- not relevant in this context since they are not executable.
5049
5050 Last_Stm := Last (S);
5051 while Nkind (Last_Stm) in N_Pop_xxx_Label loop
5052 Prev (Last_Stm);
5053 end loop;
5054
5055 -- Now insert return unless last statement is a transfer
5056
5057 if not Is_Transfer (Last_Stm) then
5058
5059 -- The source location for the return is the end label of the
5060 -- procedure if present. Otherwise use the sloc of the last
5061 -- statement in the list. If the list comes from a generated
5062 -- exception handler and we are not debugging generated code,
5063 -- all the statements within the handler are made invisible
5064 -- to the debugger.
5065
5066 if Nkind (Parent (S)) = N_Exception_Handler
5067 and then not Comes_From_Source (Parent (S))
5068 then
5069 Loc := Sloc (Last_Stm);
5070
5071 elsif Present (End_Label (H)) then
5072 Loc := Sloc (End_Label (H));
5073
5074 else
5075 Loc := Sloc (Last_Stm);
5076 end if;
5077
5078 declare
5079 Rtn : constant Node_Id := Make_Simple_Return_Statement (Loc);
5080
5081 begin
5082 -- Append return statement, and set analyzed manually. We can't
5083 -- call Analyze on this return since the scope is wrong.
5084
5085 -- Note: it almost works to push the scope and then do the
5086 -- Analyze call, but something goes wrong in some weird cases
5087 -- and it is not worth worrying about ???
5088
5089 Append_To (S, Rtn);
5090 Set_Analyzed (Rtn);
5091
5092 -- Call _Postconditions procedure if appropriate. We need to
5093 -- do this explicitly because we did not analyze the generated
5094 -- return statement above, so the call did not get inserted.
5095
5096 if Ekind (Spec_Id) = E_Procedure
5097 and then Has_Postconditions (Spec_Id)
5098 then
5099 pragma Assert (Present (Postcondition_Proc (Spec_Id)));
5100 Insert_Action (Rtn,
5101 Make_Procedure_Call_Statement (Loc,
5102 Name =>
5103 New_Reference_To (Postcondition_Proc (Spec_Id), Loc)));
5104 end if;
5105 end;
5106 end if;
5107 end Add_Return;
5108
5109 -- Start of processing for Expand_N_Subprogram_Body
5110
5111 begin
5112 -- Set L to either the list of declarations if present, or to the list
5113 -- of statements if no declarations are present. This is used to insert
5114 -- new stuff at the start.
5115
5116 if Is_Non_Empty_List (Declarations (N)) then
5117 L := Declarations (N);
5118 else
5119 L := Statements (H);
5120 end if;
5121
5122 -- If local-exception-to-goto optimization active, insert dummy push
5123 -- statements at start, and dummy pop statements at end.
5124
5125 if (Debug_Flag_Dot_G
5126 or else Restriction_Active (No_Exception_Propagation))
5127 and then Is_Non_Empty_List (L)
5128 then
5129 declare
5130 FS : constant Node_Id := First (L);
5131 FL : constant Source_Ptr := Sloc (FS);
5132 LS : Node_Id;
5133 LL : Source_Ptr;
5134
5135 begin
5136 -- LS points to either last statement, if statements are present
5137 -- or to the last declaration if there are no statements present.
5138 -- It is the node after which the pop's are generated.
5139
5140 if Is_Non_Empty_List (Statements (H)) then
5141 LS := Last (Statements (H));
5142 else
5143 LS := Last (L);
5144 end if;
5145
5146 LL := Sloc (LS);
5147
5148 Insert_List_Before_And_Analyze (FS, New_List (
5149 Make_Push_Constraint_Error_Label (FL),
5150 Make_Push_Program_Error_Label (FL),
5151 Make_Push_Storage_Error_Label (FL)));
5152
5153 Insert_List_After_And_Analyze (LS, New_List (
5154 Make_Pop_Constraint_Error_Label (LL),
5155 Make_Pop_Program_Error_Label (LL),
5156 Make_Pop_Storage_Error_Label (LL)));
5157 end;
5158 end if;
5159
5160 -- Find entity for subprogram
5161
5162 Body_Id := Defining_Entity (N);
5163
5164 if Present (Corresponding_Spec (N)) then
5165 Spec_Id := Corresponding_Spec (N);
5166 else
5167 Spec_Id := Body_Id;
5168 end if;
5169
5170 -- Need poll on entry to subprogram if polling enabled. We only do this
5171 -- for non-empty subprograms, since it does not seem necessary to poll
5172 -- for a dummy null subprogram.
5173
5174 if Is_Non_Empty_List (L) then
5175
5176 -- Do not add a polling call if the subprogram is to be inlined by
5177 -- the back-end, to avoid repeated calls with multiple inlinings.
5178
5179 if Is_Inlined (Spec_Id)
5180 and then Front_End_Inlining
5181 and then Optimization_Level > 1
5182 then
5183 null;
5184 else
5185 Generate_Poll_Call (First (L));
5186 end if;
5187 end if;
5188
5189 -- If this is a Pure function which has any parameters whose root type
5190 -- is System.Address, reset the Pure indication, since it will likely
5191 -- cause incorrect code to be generated as the parameter is probably
5192 -- a pointer, and the fact that the same pointer is passed does not mean
5193 -- that the same value is being referenced.
5194
5195 -- Note that if the programmer gave an explicit Pure_Function pragma,
5196 -- then we believe the programmer, and leave the subprogram Pure.
5197
5198 -- This code should probably be at the freeze point, so that it happens
5199 -- even on a -gnatc (or more importantly -gnatt) compile, so that the
5200 -- semantic tree has Is_Pure set properly ???
5201
5202 if Is_Pure (Spec_Id)
5203 and then Is_Subprogram (Spec_Id)
5204 and then not Has_Pragma_Pure_Function (Spec_Id)
5205 then
5206 declare
5207 F : Entity_Id;
5208
5209 begin
5210 F := First_Formal (Spec_Id);
5211 while Present (F) loop
5212 if Is_Descendent_Of_Address (Etype (F))
5213
5214 -- Note that this test is being made in the body of the
5215 -- subprogram, not the spec, so we are testing the full
5216 -- type for being limited here, as required.
5217
5218 or else Is_Limited_Type (Etype (F))
5219 then
5220 Set_Is_Pure (Spec_Id, False);
5221
5222 if Spec_Id /= Body_Id then
5223 Set_Is_Pure (Body_Id, False);
5224 end if;
5225
5226 exit;
5227 end if;
5228
5229 Next_Formal (F);
5230 end loop;
5231 end;
5232 end if;
5233
5234 -- Initialize any scalar OUT args if Initialize/Normalize_Scalars
5235
5236 if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then
5237 declare
5238 F : Entity_Id;
5239
5240 begin
5241 -- Loop through formals
5242
5243 F := First_Formal (Spec_Id);
5244 while Present (F) loop
5245 if Is_Scalar_Type (Etype (F))
5246 and then Ekind (F) = E_Out_Parameter
5247 then
5248 Check_Restriction (No_Default_Initialization, F);
5249
5250 -- Insert the initialization. We turn off validity checks
5251 -- for this assignment, since we do not want any check on
5252 -- the initial value itself (which may well be invalid).
5253
5254 Insert_Before_And_Analyze (First (L),
5255 Make_Assignment_Statement (Loc,
5256 Name => New_Occurrence_Of (F, Loc),
5257 Expression => Get_Simple_Init_Val (Etype (F), N)),
5258 Suppress => Validity_Check);
5259 end if;
5260
5261 Next_Formal (F);
5262 end loop;
5263 end;
5264 end if;
5265
5266 -- Clear out statement list for stubbed procedure
5267
5268 if Present (Corresponding_Spec (N)) then
5269 Set_Elaboration_Flag (N, Spec_Id);
5270
5271 if Convention (Spec_Id) = Convention_Stubbed
5272 or else Is_Eliminated (Spec_Id)
5273 then
5274 Set_Declarations (N, Empty_List);
5275 Set_Handled_Statement_Sequence (N,
5276 Make_Handled_Sequence_Of_Statements (Loc,
5277 Statements => New_List (
5278 Make_Null_Statement (Loc))));
5279 return;
5280 end if;
5281 end if;
5282
5283 -- Create a set of discriminals for the next protected subprogram body
5284
5285 if Is_List_Member (N)
5286 and then Present (Parent (List_Containing (N)))
5287 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
5288 and then Present (Next_Protected_Operation (N))
5289 then
5290 Set_Discriminals (Parent (Base_Type (Scope (Spec_Id))));
5291 end if;
5292
5293 -- Returns_By_Ref flag is normally set when the subprogram is frozen but
5294 -- subprograms with no specs are not frozen.
5295
5296 declare
5297 Typ : constant Entity_Id := Etype (Spec_Id);
5298 Utyp : constant Entity_Id := Underlying_Type (Typ);
5299
5300 begin
5301 if not Acts_As_Spec (N)
5302 and then Nkind (Parent (Parent (Spec_Id))) /=
5303 N_Subprogram_Body_Stub
5304 then
5305 null;
5306
5307 elsif Is_Immutably_Limited_Type (Typ) then
5308 Set_Returns_By_Ref (Spec_Id);
5309
5310 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
5311 Set_Returns_By_Ref (Spec_Id);
5312 end if;
5313 end;
5314
5315 -- For a procedure, we add a return for all possible syntactic ends of
5316 -- the subprogram.
5317
5318 if Ekind_In (Spec_Id, E_Procedure, E_Generic_Procedure) then
5319 Add_Return (Statements (H));
5320
5321 if Present (Exception_Handlers (H)) then
5322 Except_H := First_Non_Pragma (Exception_Handlers (H));
5323 while Present (Except_H) loop
5324 Add_Return (Statements (Except_H));
5325 Next_Non_Pragma (Except_H);
5326 end loop;
5327 end if;
5328
5329 -- For a function, we must deal with the case where there is at least
5330 -- one missing return. What we do is to wrap the entire body of the
5331 -- function in a block:
5332
5333 -- begin
5334 -- ...
5335 -- end;
5336
5337 -- becomes
5338
5339 -- begin
5340 -- begin
5341 -- ...
5342 -- end;
5343
5344 -- raise Program_Error;
5345 -- end;
5346
5347 -- This approach is necessary because the raise must be signalled to the
5348 -- caller, not handled by any local handler (RM 6.4(11)).
5349
5350 -- Note: we do not need to analyze the constructed sequence here, since
5351 -- it has no handler, and an attempt to analyze the handled statement
5352 -- sequence twice is risky in various ways (e.g. the issue of expanding
5353 -- cleanup actions twice).
5354
5355 elsif Has_Missing_Return (Spec_Id) then
5356 declare
5357 Hloc : constant Source_Ptr := Sloc (H);
5358 Blok : constant Node_Id :=
5359 Make_Block_Statement (Hloc,
5360 Handled_Statement_Sequence => H);
5361 Rais : constant Node_Id :=
5362 Make_Raise_Program_Error (Hloc,
5363 Reason => PE_Missing_Return);
5364
5365 begin
5366 Set_Handled_Statement_Sequence (N,
5367 Make_Handled_Sequence_Of_Statements (Hloc,
5368 Statements => New_List (Blok, Rais)));
5369
5370 Push_Scope (Spec_Id);
5371 Analyze (Blok);
5372 Analyze (Rais);
5373 Pop_Scope;
5374 end;
5375 end if;
5376
5377 -- If subprogram contains a parameterless recursive call, then we may
5378 -- have an infinite recursion, so see if we can generate code to check
5379 -- for this possibility if storage checks are not suppressed.
5380
5381 if Ekind (Spec_Id) = E_Procedure
5382 and then Has_Recursive_Call (Spec_Id)
5383 and then not Storage_Checks_Suppressed (Spec_Id)
5384 then
5385 Detect_Infinite_Recursion (N, Spec_Id);
5386 end if;
5387
5388 -- Set to encode entity names in package body before gigi is called
5389
5390 Qualify_Entity_Names (N);
5391 end Expand_N_Subprogram_Body;
5392
5393 -----------------------------------
5394 -- Expand_N_Subprogram_Body_Stub --
5395 -----------------------------------
5396
5397 procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is
5398 begin
5399 if Present (Corresponding_Body (N)) then
5400 Expand_N_Subprogram_Body (
5401 Unit_Declaration_Node (Corresponding_Body (N)));
5402 end if;
5403 end Expand_N_Subprogram_Body_Stub;
5404
5405 -------------------------------------
5406 -- Expand_N_Subprogram_Declaration --
5407 -------------------------------------
5408
5409 -- If the declaration appears within a protected body, it is a private
5410 -- operation of the protected type. We must create the corresponding
5411 -- protected subprogram an associated formals. For a normal protected
5412 -- operation, this is done when expanding the protected type declaration.
5413
5414 -- If the declaration is for a null procedure, emit null body
5415
5416 procedure Expand_N_Subprogram_Declaration (N : Node_Id) is
5417 Loc : constant Source_Ptr := Sloc (N);
5418 Subp : constant Entity_Id := Defining_Entity (N);
5419 Scop : constant Entity_Id := Scope (Subp);
5420 Prot_Decl : Node_Id;
5421 Prot_Bod : Node_Id;
5422 Prot_Id : Entity_Id;
5423
5424 begin
5425 -- Deal with case of protected subprogram. Do not generate protected
5426 -- operation if operation is flagged as eliminated.
5427
5428 if Is_List_Member (N)
5429 and then Present (Parent (List_Containing (N)))
5430 and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
5431 and then Is_Protected_Type (Scop)
5432 then
5433 if No (Protected_Body_Subprogram (Subp))
5434 and then not Is_Eliminated (Subp)
5435 then
5436 Prot_Decl :=
5437 Make_Subprogram_Declaration (Loc,
5438 Specification =>
5439 Build_Protected_Sub_Specification
5440 (N, Scop, Unprotected_Mode));
5441
5442 -- The protected subprogram is declared outside of the protected
5443 -- body. Given that the body has frozen all entities so far, we
5444 -- analyze the subprogram and perform freezing actions explicitly.
5445 -- including the generation of an explicit freeze node, to ensure
5446 -- that gigi has the proper order of elaboration.
5447 -- If the body is a subunit, the insertion point is before the
5448 -- stub in the parent.
5449
5450 Prot_Bod := Parent (List_Containing (N));
5451
5452 if Nkind (Parent (Prot_Bod)) = N_Subunit then
5453 Prot_Bod := Corresponding_Stub (Parent (Prot_Bod));
5454 end if;
5455
5456 Insert_Before (Prot_Bod, Prot_Decl);
5457 Prot_Id := Defining_Unit_Name (Specification (Prot_Decl));
5458 Set_Has_Delayed_Freeze (Prot_Id);
5459
5460 Push_Scope (Scope (Scop));
5461 Analyze (Prot_Decl);
5462 Insert_Actions (N, Freeze_Entity (Prot_Id, N));
5463 Set_Protected_Body_Subprogram (Subp, Prot_Id);
5464
5465 -- Create protected operation as well. Even though the operation
5466 -- is only accessible within the body, it is possible to make it
5467 -- available outside of the protected object by using 'Access to
5468 -- provide a callback, so build protected version in all cases.
5469
5470 Prot_Decl :=
5471 Make_Subprogram_Declaration (Loc,
5472 Specification =>
5473 Build_Protected_Sub_Specification (N, Scop, Protected_Mode));
5474 Insert_Before (Prot_Bod, Prot_Decl);
5475 Analyze (Prot_Decl);
5476
5477 Pop_Scope;
5478 end if;
5479
5480 -- Ada 2005 (AI-348): Generate body for a null procedure.
5481 -- In most cases this is superfluous because calls to it
5482 -- will be automatically inlined, but we definitely need
5483 -- the body if preconditions for the procedure are present.
5484
5485 elsif Nkind (Specification (N)) = N_Procedure_Specification
5486 and then Null_Present (Specification (N))
5487 then
5488 declare
5489 Bod : constant Node_Id := Body_To_Inline (N);
5490
5491 begin
5492 Set_Has_Completion (Subp, False);
5493 Append_Freeze_Action (Subp, Bod);
5494
5495 -- The body now contains raise statements, so calls to it will
5496 -- not be inlined.
5497
5498 Set_Is_Inlined (Subp, False);
5499 end;
5500 end if;
5501 end Expand_N_Subprogram_Declaration;
5502
5503 --------------------------------
5504 -- Expand_Non_Function_Return --
5505 --------------------------------
5506
5507 procedure Expand_Non_Function_Return (N : Node_Id) is
5508 pragma Assert (No (Expression (N)));
5509
5510 Loc : constant Source_Ptr := Sloc (N);
5511 Scope_Id : Entity_Id :=
5512 Return_Applies_To (Return_Statement_Entity (N));
5513 Kind : constant Entity_Kind := Ekind (Scope_Id);
5514 Call : Node_Id;
5515 Acc_Stat : Node_Id;
5516 Goto_Stat : Node_Id;
5517 Lab_Node : Node_Id;
5518
5519 begin
5520 -- Call _Postconditions procedure if procedure with active
5521 -- postconditions. Here, we use the Postcondition_Proc attribute, which
5522 -- is needed for implicitly-generated returns. Functions never
5523 -- have implicitly-generated returns, and there's no room for
5524 -- Postcondition_Proc in E_Function, so we look up the identifier
5525 -- Name_uPostconditions for function returns (see
5526 -- Expand_Simple_Function_Return).
5527
5528 if Ekind (Scope_Id) = E_Procedure
5529 and then Has_Postconditions (Scope_Id)
5530 then
5531 pragma Assert (Present (Postcondition_Proc (Scope_Id)));
5532 Insert_Action (N,
5533 Make_Procedure_Call_Statement (Loc,
5534 Name => New_Reference_To (Postcondition_Proc (Scope_Id), Loc)));
5535 end if;
5536
5537 -- If it is a return from a procedure do no extra steps
5538
5539 if Kind = E_Procedure or else Kind = E_Generic_Procedure then
5540 return;
5541
5542 -- If it is a nested return within an extended one, replace it with a
5543 -- return of the previously declared return object.
5544
5545 elsif Kind = E_Return_Statement then
5546 Rewrite (N,
5547 Make_Simple_Return_Statement (Loc,
5548 Expression =>
5549 New_Occurrence_Of (First_Entity (Scope_Id), Loc)));
5550 Set_Comes_From_Extended_Return_Statement (N);
5551 Set_Return_Statement_Entity (N, Scope_Id);
5552 Expand_Simple_Function_Return (N);
5553 return;
5554 end if;
5555
5556 pragma Assert (Is_Entry (Scope_Id));
5557
5558 -- Look at the enclosing block to see whether the return is from an
5559 -- accept statement or an entry body.
5560
5561 for J in reverse 0 .. Scope_Stack.Last loop
5562 Scope_Id := Scope_Stack.Table (J).Entity;
5563 exit when Is_Concurrent_Type (Scope_Id);
5564 end loop;
5565
5566 -- If it is a return from accept statement it is expanded as call to
5567 -- RTS Complete_Rendezvous and a goto to the end of the accept body.
5568
5569 -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept,
5570 -- Expand_N_Accept_Alternative in exp_ch9.adb)
5571
5572 if Is_Task_Type (Scope_Id) then
5573
5574 Call :=
5575 Make_Procedure_Call_Statement (Loc,
5576 Name => New_Reference_To (RTE (RE_Complete_Rendezvous), Loc));
5577 Insert_Before (N, Call);
5578 -- why not insert actions here???
5579 Analyze (Call);
5580
5581 Acc_Stat := Parent (N);
5582 while Nkind (Acc_Stat) /= N_Accept_Statement loop
5583 Acc_Stat := Parent (Acc_Stat);
5584 end loop;
5585
5586 Lab_Node := Last (Statements
5587 (Handled_Statement_Sequence (Acc_Stat)));
5588
5589 Goto_Stat := Make_Goto_Statement (Loc,
5590 Name => New_Occurrence_Of
5591 (Entity (Identifier (Lab_Node)), Loc));
5592
5593 Set_Analyzed (Goto_Stat);
5594
5595 Rewrite (N, Goto_Stat);
5596 Analyze (N);
5597
5598 -- If it is a return from an entry body, put a Complete_Entry_Body call
5599 -- in front of the return.
5600
5601 elsif Is_Protected_Type (Scope_Id) then
5602 Call :=
5603 Make_Procedure_Call_Statement (Loc,
5604 Name =>
5605 New_Reference_To (RTE (RE_Complete_Entry_Body), Loc),
5606 Parameter_Associations => New_List (
5607 Make_Attribute_Reference (Loc,
5608 Prefix =>
5609 New_Reference_To
5610 (Find_Protection_Object (Current_Scope), Loc),
5611 Attribute_Name =>
5612 Name_Unchecked_Access)));
5613
5614 Insert_Before (N, Call);
5615 Analyze (Call);
5616 end if;
5617 end Expand_Non_Function_Return;
5618
5619 ---------------------------------------
5620 -- Expand_Protected_Object_Reference --
5621 ---------------------------------------
5622
5623 function Expand_Protected_Object_Reference
5624 (N : Node_Id;
5625 Scop : Entity_Id) return Node_Id
5626 is
5627 Loc : constant Source_Ptr := Sloc (N);
5628 Corr : Entity_Id;
5629 Rec : Node_Id;
5630 Param : Entity_Id;
5631 Proc : Entity_Id;
5632
5633 begin
5634 Rec :=
5635 Make_Identifier (Loc,
5636 Chars => Name_uObject);
5637 Set_Etype (Rec, Corresponding_Record_Type (Scop));
5638
5639 -- Find enclosing protected operation, and retrieve its first parameter,
5640 -- which denotes the enclosing protected object. If the enclosing
5641 -- operation is an entry, we are immediately within the protected body,
5642 -- and we can retrieve the object from the service entries procedure. A
5643 -- barrier function has the same signature as an entry. A barrier
5644 -- function is compiled within the protected object, but unlike
5645 -- protected operations its never needs locks, so that its protected
5646 -- body subprogram points to itself.
5647
5648 Proc := Current_Scope;
5649 while Present (Proc)
5650 and then Scope (Proc) /= Scop
5651 loop
5652 Proc := Scope (Proc);
5653 end loop;
5654
5655 Corr := Protected_Body_Subprogram (Proc);
5656
5657 if No (Corr) then
5658
5659 -- Previous error left expansion incomplete.
5660 -- Nothing to do on this call.
5661
5662 return Empty;
5663 end if;
5664
5665 Param :=
5666 Defining_Identifier
5667 (First (Parameter_Specifications (Parent (Corr))));
5668
5669 if Is_Subprogram (Proc)
5670 and then Proc /= Corr
5671 then
5672 -- Protected function or procedure
5673
5674 Set_Entity (Rec, Param);
5675
5676 -- Rec is a reference to an entity which will not be in scope when
5677 -- the call is reanalyzed, and needs no further analysis.
5678
5679 Set_Analyzed (Rec);
5680
5681 else
5682 -- Entry or barrier function for entry body. The first parameter of
5683 -- the entry body procedure is pointer to the object. We create a
5684 -- local variable of the proper type, duplicating what is done to
5685 -- define _object later on.
5686
5687 declare
5688 Decls : List_Id;
5689 Obj_Ptr : constant Entity_Id := Make_Temporary (Loc, 'T');
5690
5691 begin
5692 Decls := New_List (
5693 Make_Full_Type_Declaration (Loc,
5694 Defining_Identifier => Obj_Ptr,
5695 Type_Definition =>
5696 Make_Access_To_Object_Definition (Loc,
5697 Subtype_Indication =>
5698 New_Reference_To
5699 (Corresponding_Record_Type (Scop), Loc))));
5700
5701 Insert_Actions (N, Decls);
5702 Insert_Actions (N, Freeze_Entity (Obj_Ptr, N));
5703
5704 Rec :=
5705 Make_Explicit_Dereference (Loc,
5706 Unchecked_Convert_To (Obj_Ptr,
5707 New_Occurrence_Of (Param, Loc)));
5708
5709 -- Analyze new actual. Other actuals in calls are already analyzed
5710 -- and the list of actuals is not reanalyzed after rewriting.
5711
5712 Set_Parent (Rec, N);
5713 Analyze (Rec);
5714 end;
5715 end if;
5716
5717 return Rec;
5718 end Expand_Protected_Object_Reference;
5719
5720 --------------------------------------
5721 -- Expand_Protected_Subprogram_Call --
5722 --------------------------------------
5723
5724 procedure Expand_Protected_Subprogram_Call
5725 (N : Node_Id;
5726 Subp : Entity_Id;
5727 Scop : Entity_Id)
5728 is
5729 Rec : Node_Id;
5730
5731 begin
5732 -- If the protected object is not an enclosing scope, this is
5733 -- an inter-object function call. Inter-object procedure
5734 -- calls are expanded by Exp_Ch9.Build_Simple_Entry_Call.
5735 -- The call is intra-object only if the subprogram being
5736 -- called is in the protected body being compiled, and if the
5737 -- protected object in the call is statically the enclosing type.
5738 -- The object may be an component of some other data structure,
5739 -- in which case this must be handled as an inter-object call.
5740
5741 if not In_Open_Scopes (Scop)
5742 or else not Is_Entity_Name (Name (N))
5743 then
5744 if Nkind (Name (N)) = N_Selected_Component then
5745 Rec := Prefix (Name (N));
5746
5747 else
5748 pragma Assert (Nkind (Name (N)) = N_Indexed_Component);
5749 Rec := Prefix (Prefix (Name (N)));
5750 end if;
5751
5752 Build_Protected_Subprogram_Call (N,
5753 Name => New_Occurrence_Of (Subp, Sloc (N)),
5754 Rec => Convert_Concurrent (Rec, Etype (Rec)),
5755 External => True);
5756
5757 else
5758 Rec := Expand_Protected_Object_Reference (N, Scop);
5759
5760 if No (Rec) then
5761 return;
5762 end if;
5763
5764 Build_Protected_Subprogram_Call (N,
5765 Name => Name (N),
5766 Rec => Rec,
5767 External => False);
5768
5769 end if;
5770
5771 -- If it is a function call it can appear in elaboration code and
5772 -- the called entity must be frozen here.
5773
5774 if Ekind (Subp) = E_Function then
5775 Freeze_Expression (Name (N));
5776 end if;
5777
5778 -- Analyze and resolve the new call. The actuals have already been
5779 -- resolved, but expansion of a function call will add extra actuals
5780 -- if needed. Analysis of a procedure call already includes resolution.
5781
5782 Analyze (N);
5783
5784 if Ekind (Subp) = E_Function then
5785 Resolve (N, Etype (Subp));
5786 end if;
5787 end Expand_Protected_Subprogram_Call;
5788
5789 -----------------------------------
5790 -- Expand_Simple_Function_Return --
5791 -----------------------------------
5792
5793 -- The "simple" comes from the syntax rule simple_return_statement.
5794 -- The semantics are not at all simple!
5795
5796 procedure Expand_Simple_Function_Return (N : Node_Id) is
5797 Loc : constant Source_Ptr := Sloc (N);
5798
5799 Scope_Id : constant Entity_Id :=
5800 Return_Applies_To (Return_Statement_Entity (N));
5801 -- The function we are returning from
5802
5803 R_Type : constant Entity_Id := Etype (Scope_Id);
5804 -- The result type of the function
5805
5806 Utyp : constant Entity_Id := Underlying_Type (R_Type);
5807
5808 Exp : constant Node_Id := Expression (N);
5809 pragma Assert (Present (Exp));
5810
5811 Exptyp : constant Entity_Id := Etype (Exp);
5812 -- The type of the expression (not necessarily the same as R_Type)
5813
5814 Subtype_Ind : Node_Id;
5815 -- If the result type of the function is class-wide and the
5816 -- expression has a specific type, then we use the expression's
5817 -- type as the type of the return object. In cases where the
5818 -- expression is an aggregate that is built in place, this avoids
5819 -- the need for an expensive conversion of the return object to
5820 -- the specific type on assignments to the individual components.
5821
5822 begin
5823 if Is_Class_Wide_Type (R_Type)
5824 and then not Is_Class_Wide_Type (Etype (Exp))
5825 then
5826 Subtype_Ind := New_Occurrence_Of (Etype (Exp), Loc);
5827 else
5828 Subtype_Ind := New_Occurrence_Of (R_Type, Loc);
5829 end if;
5830
5831 -- For the case of a simple return that does not come from an extended
5832 -- return, in the case of Ada 2005 where we are returning a limited
5833 -- type, we rewrite "return <expression>;" to be:
5834
5835 -- return _anon_ : <return_subtype> := <expression>
5836
5837 -- The expansion produced by Expand_N_Extended_Return_Statement will
5838 -- contain simple return statements (for example, a block containing
5839 -- simple return of the return object), which brings us back here with
5840 -- Comes_From_Extended_Return_Statement set. The reason for the barrier
5841 -- checking for a simple return that does not come from an extended
5842 -- return is to avoid this infinite recursion.
5843
5844 -- The reason for this design is that for Ada 2005 limited returns, we
5845 -- need to reify the return object, so we can build it "in place", and
5846 -- we need a block statement to hang finalization and tasking stuff.
5847
5848 -- ??? In order to avoid disruption, we avoid translating to extended
5849 -- return except in the cases where we really need to (Ada 2005 for
5850 -- inherently limited). We might prefer to do this translation in all
5851 -- cases (except perhaps for the case of Ada 95 inherently limited),
5852 -- in order to fully exercise the Expand_N_Extended_Return_Statement
5853 -- code. This would also allow us to do the build-in-place optimization
5854 -- for efficiency even in cases where it is semantically not required.
5855
5856 -- As before, we check the type of the return expression rather than the
5857 -- return type of the function, because the latter may be a limited
5858 -- class-wide interface type, which is not a limited type, even though
5859 -- the type of the expression may be.
5860
5861 if not Comes_From_Extended_Return_Statement (N)
5862 and then Is_Immutably_Limited_Type (Etype (Expression (N)))
5863 and then Ada_Version >= Ada_2005
5864 and then not Debug_Flag_Dot_L
5865 then
5866 declare
5867 Return_Object_Entity : constant Entity_Id :=
5868 Make_Temporary (Loc, 'R', Exp);
5869 Obj_Decl : constant Node_Id :=
5870 Make_Object_Declaration (Loc,
5871 Defining_Identifier => Return_Object_Entity,
5872 Object_Definition => Subtype_Ind,
5873 Expression => Exp);
5874
5875 Ext : constant Node_Id := Make_Extended_Return_Statement (Loc,
5876 Return_Object_Declarations => New_List (Obj_Decl));
5877 -- Do not perform this high-level optimization if the result type
5878 -- is an interface because the "this" pointer must be displaced.
5879
5880 begin
5881 Rewrite (N, Ext);
5882 Analyze (N);
5883 return;
5884 end;
5885 end if;
5886
5887 -- Here we have a simple return statement that is part of the expansion
5888 -- of an extended return statement (either written by the user, or
5889 -- generated by the above code).
5890
5891 -- Always normalize C/Fortran boolean result. This is not always needed,
5892 -- but it seems a good idea to minimize the passing around of non-
5893 -- normalized values, and in any case this handles the processing of
5894 -- barrier functions for protected types, which turn the condition into
5895 -- a return statement.
5896
5897 if Is_Boolean_Type (Exptyp)
5898 and then Nonzero_Is_True (Exptyp)
5899 then
5900 Adjust_Condition (Exp);
5901 Adjust_Result_Type (Exp, Exptyp);
5902 end if;
5903
5904 -- Do validity check if enabled for returns
5905
5906 if Validity_Checks_On
5907 and then Validity_Check_Returns
5908 then
5909 Ensure_Valid (Exp);
5910 end if;
5911
5912 -- Check the result expression of a scalar function against the subtype
5913 -- of the function by inserting a conversion. This conversion must
5914 -- eventually be performed for other classes of types, but for now it's
5915 -- only done for scalars.
5916 -- ???
5917
5918 if Is_Scalar_Type (Exptyp) then
5919 Rewrite (Exp, Convert_To (R_Type, Exp));
5920
5921 -- The expression is resolved to ensure that the conversion gets
5922 -- expanded to generate a possible constraint check.
5923
5924 Analyze_And_Resolve (Exp, R_Type);
5925 end if;
5926
5927 -- Deal with returning variable length objects and controlled types
5928
5929 -- Nothing to do if we are returning by reference, or this is not a
5930 -- type that requires special processing (indicated by the fact that
5931 -- it requires a cleanup scope for the secondary stack case).
5932
5933 if Is_Immutably_Limited_Type (Exptyp)
5934 or else Is_Limited_Interface (Exptyp)
5935 then
5936 null;
5937
5938 elsif not Requires_Transient_Scope (R_Type) then
5939
5940 -- Mutable records with no variable length components are not
5941 -- returned on the sec-stack, so we need to make sure that the
5942 -- backend will only copy back the size of the actual value, and not
5943 -- the maximum size. We create an actual subtype for this purpose.
5944
5945 declare
5946 Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exptyp));
5947 Decl : Node_Id;
5948 Ent : Entity_Id;
5949 begin
5950 if Has_Discriminants (Ubt)
5951 and then not Is_Constrained (Ubt)
5952 and then not Has_Unchecked_Union (Ubt)
5953 then
5954 Decl := Build_Actual_Subtype (Ubt, Exp);
5955 Ent := Defining_Identifier (Decl);
5956 Insert_Action (Exp, Decl);
5957 Rewrite (Exp, Unchecked_Convert_To (Ent, Exp));
5958 Analyze_And_Resolve (Exp);
5959 end if;
5960 end;
5961
5962 -- Here if secondary stack is used
5963
5964 else
5965 -- Make sure that no surrounding block will reclaim the secondary
5966 -- stack on which we are going to put the result. Not only may this
5967 -- introduce secondary stack leaks but worse, if the reclamation is
5968 -- done too early, then the result we are returning may get
5969 -- clobbered.
5970
5971 declare
5972 S : Entity_Id;
5973 begin
5974 S := Current_Scope;
5975 while Ekind (S) = E_Block or else Ekind (S) = E_Loop loop
5976 Set_Sec_Stack_Needed_For_Return (S, True);
5977 S := Enclosing_Dynamic_Scope (S);
5978 end loop;
5979 end;
5980
5981 -- Optimize the case where the result is a function call. In this
5982 -- case either the result is already on the secondary stack, or is
5983 -- already being returned with the stack pointer depressed and no
5984 -- further processing is required except to set the By_Ref flag to
5985 -- ensure that gigi does not attempt an extra unnecessary copy.
5986 -- (actually not just unnecessary but harmfully wrong in the case
5987 -- of a controlled type, where gigi does not know how to do a copy).
5988 -- To make up for a gcc 2.8.1 deficiency (???), we perform
5989 -- the copy for array types if the constrained status of the
5990 -- target type is different from that of the expression.
5991
5992 if Requires_Transient_Scope (Exptyp)
5993 and then
5994 (not Is_Array_Type (Exptyp)
5995 or else Is_Constrained (Exptyp) = Is_Constrained (R_Type)
5996 or else CW_Or_Has_Controlled_Part (Utyp))
5997 and then Nkind (Exp) = N_Function_Call
5998 then
5999 Set_By_Ref (N);
6000
6001 -- Remove side effects from the expression now so that other parts
6002 -- of the expander do not have to reanalyze this node without this
6003 -- optimization
6004
6005 Rewrite (Exp, Duplicate_Subexpr_No_Checks (Exp));
6006
6007 -- For controlled types, do the allocation on the secondary stack
6008 -- manually in order to call adjust at the right time:
6009
6010 -- type Anon1 is access R_Type;
6011 -- for Anon1'Storage_pool use ss_pool;
6012 -- Anon2 : anon1 := new R_Type'(expr);
6013 -- return Anon2.all;
6014
6015 -- We do the same for classwide types that are not potentially
6016 -- controlled (by the virtue of restriction No_Finalization) because
6017 -- gigi is not able to properly allocate class-wide types.
6018
6019 elsif CW_Or_Has_Controlled_Part (Utyp) then
6020 declare
6021 Loc : constant Source_Ptr := Sloc (N);
6022 Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
6023 Alloc_Node : Node_Id;
6024 Temp : Entity_Id;
6025
6026 begin
6027 Set_Ekind (Acc_Typ, E_Access_Type);
6028
6029 Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool));
6030
6031 -- This is an allocator for the secondary stack, and it's fine
6032 -- to have Comes_From_Source set False on it, as gigi knows not
6033 -- to flag it as a violation of No_Implicit_Heap_Allocations.
6034
6035 Alloc_Node :=
6036 Make_Allocator (Loc,
6037 Expression =>
6038 Make_Qualified_Expression (Loc,
6039 Subtype_Mark => New_Reference_To (Etype (Exp), Loc),
6040 Expression => Relocate_Node (Exp)));
6041
6042 -- We do not want discriminant checks on the declaration,
6043 -- given that it gets its value from the allocator.
6044
6045 Set_No_Initialization (Alloc_Node);
6046
6047 Temp := Make_Temporary (Loc, 'R', Alloc_Node);
6048
6049 Insert_List_Before_And_Analyze (N, New_List (
6050 Make_Full_Type_Declaration (Loc,
6051 Defining_Identifier => Acc_Typ,
6052 Type_Definition =>
6053 Make_Access_To_Object_Definition (Loc,
6054 Subtype_Indication => Subtype_Ind)),
6055
6056 Make_Object_Declaration (Loc,
6057 Defining_Identifier => Temp,
6058 Object_Definition => New_Reference_To (Acc_Typ, Loc),
6059 Expression => Alloc_Node)));
6060
6061 Rewrite (Exp,
6062 Make_Explicit_Dereference (Loc,
6063 Prefix => New_Reference_To (Temp, Loc)));
6064
6065 Analyze_And_Resolve (Exp, R_Type);
6066 end;
6067
6068 -- Otherwise use the gigi mechanism to allocate result on the
6069 -- secondary stack.
6070
6071 else
6072 Check_Restriction (No_Secondary_Stack, N);
6073 Set_Storage_Pool (N, RTE (RE_SS_Pool));
6074
6075 -- If we are generating code for the VM do not use
6076 -- SS_Allocate since everything is heap-allocated anyway.
6077
6078 if VM_Target = No_VM then
6079 Set_Procedure_To_Call (N, RTE (RE_SS_Allocate));
6080 end if;
6081 end if;
6082 end if;
6083
6084 -- Implement the rules of 6.5(8-10), which require a tag check in the
6085 -- case of a limited tagged return type, and tag reassignment for
6086 -- nonlimited tagged results. These actions are needed when the return
6087 -- type is a specific tagged type and the result expression is a
6088 -- conversion or a formal parameter, because in that case the tag of the
6089 -- expression might differ from the tag of the specific result type.
6090
6091 if Is_Tagged_Type (Utyp)
6092 and then not Is_Class_Wide_Type (Utyp)
6093 and then (Nkind_In (Exp, N_Type_Conversion,
6094 N_Unchecked_Type_Conversion)
6095 or else (Is_Entity_Name (Exp)
6096 and then Ekind (Entity (Exp)) in Formal_Kind))
6097 then
6098 -- When the return type is limited, perform a check that the
6099 -- tag of the result is the same as the tag of the return type.
6100
6101 if Is_Limited_Type (R_Type) then
6102 Insert_Action (Exp,
6103 Make_Raise_Constraint_Error (Loc,
6104 Condition =>
6105 Make_Op_Ne (Loc,
6106 Left_Opnd =>
6107 Make_Selected_Component (Loc,
6108 Prefix => Duplicate_Subexpr (Exp),
6109 Selector_Name =>
6110 Make_Identifier (Loc, Chars => Name_uTag)),
6111 Right_Opnd =>
6112 Make_Attribute_Reference (Loc,
6113 Prefix => New_Occurrence_Of (Base_Type (Utyp), Loc),
6114 Attribute_Name => Name_Tag)),
6115 Reason => CE_Tag_Check_Failed));
6116
6117 -- If the result type is a specific nonlimited tagged type, then we
6118 -- have to ensure that the tag of the result is that of the result
6119 -- type. This is handled by making a copy of the expression in the
6120 -- case where it might have a different tag, namely when the
6121 -- expression is a conversion or a formal parameter. We create a new
6122 -- object of the result type and initialize it from the expression,
6123 -- which will implicitly force the tag to be set appropriately.
6124
6125 else
6126 declare
6127 ExpR : constant Node_Id := Relocate_Node (Exp);
6128 Result_Id : constant Entity_Id :=
6129 Make_Temporary (Loc, 'R', ExpR);
6130 Result_Exp : constant Node_Id :=
6131 New_Reference_To (Result_Id, Loc);
6132 Result_Obj : constant Node_Id :=
6133 Make_Object_Declaration (Loc,
6134 Defining_Identifier => Result_Id,
6135 Object_Definition =>
6136 New_Reference_To (R_Type, Loc),
6137 Constant_Present => True,
6138 Expression => ExpR);
6139
6140 begin
6141 Set_Assignment_OK (Result_Obj);
6142 Insert_Action (Exp, Result_Obj);
6143
6144 Rewrite (Exp, Result_Exp);
6145 Analyze_And_Resolve (Exp, R_Type);
6146 end;
6147 end if;
6148
6149 -- Ada 2005 (AI-344): If the result type is class-wide, then insert
6150 -- a check that the level of the return expression's underlying type
6151 -- is not deeper than the level of the master enclosing the function.
6152 -- Always generate the check when the type of the return expression
6153 -- is class-wide, when it's a type conversion, or when it's a formal
6154 -- parameter. Otherwise, suppress the check in the case where the
6155 -- return expression has a specific type whose level is known not to
6156 -- be statically deeper than the function's result type.
6157
6158 -- Note: accessibility check is skipped in the VM case, since there
6159 -- does not seem to be any practical way to implement this check.
6160
6161 elsif Ada_Version >= Ada_2005
6162 and then Tagged_Type_Expansion
6163 and then Is_Class_Wide_Type (R_Type)
6164 and then not Scope_Suppress (Accessibility_Check)
6165 and then
6166 (Is_Class_Wide_Type (Etype (Exp))
6167 or else Nkind_In (Exp, N_Type_Conversion,
6168 N_Unchecked_Type_Conversion)
6169 or else (Is_Entity_Name (Exp)
6170 and then Ekind (Entity (Exp)) in Formal_Kind)
6171 or else Scope_Depth (Enclosing_Dynamic_Scope (Etype (Exp))) >
6172 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))
6173 then
6174 declare
6175 Tag_Node : Node_Id;
6176
6177 begin
6178 -- Ada 2005 (AI-251): In class-wide interface objects we displace
6179 -- "this" to reference the base of the object --- required to get
6180 -- access to the TSD of the object.
6181
6182 if Is_Class_Wide_Type (Etype (Exp))
6183 and then Is_Interface (Etype (Exp))
6184 and then Nkind (Exp) = N_Explicit_Dereference
6185 then
6186 Tag_Node :=
6187 Make_Explicit_Dereference (Loc,
6188 Unchecked_Convert_To (RTE (RE_Tag_Ptr),
6189 Make_Function_Call (Loc,
6190 Name => New_Reference_To (RTE (RE_Base_Address), Loc),
6191 Parameter_Associations => New_List (
6192 Unchecked_Convert_To (RTE (RE_Address),
6193 Duplicate_Subexpr (Prefix (Exp)))))));
6194 else
6195 Tag_Node :=
6196 Make_Attribute_Reference (Loc,
6197 Prefix => Duplicate_Subexpr (Exp),
6198 Attribute_Name => Name_Tag);
6199 end if;
6200
6201 Insert_Action (Exp,
6202 Make_Raise_Program_Error (Loc,
6203 Condition =>
6204 Make_Op_Gt (Loc,
6205 Left_Opnd =>
6206 Build_Get_Access_Level (Loc, Tag_Node),
6207 Right_Opnd =>
6208 Make_Integer_Literal (Loc,
6209 Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))),
6210 Reason => PE_Accessibility_Check_Failed));
6211 end;
6212
6213 -- AI05-0073: If function has a controlling access result, check that
6214 -- the tag of the return value, if it is not null, matches designated
6215 -- type of return type.
6216 -- The return expression is referenced twice in the code below, so
6217 -- it must be made free of side effects. Given that different compilers
6218 -- may evaluate these parameters in different order, both occurrences
6219 -- perform a copy.
6220
6221 elsif Ekind (R_Type) = E_Anonymous_Access_Type
6222 and then Has_Controlling_Result (Scope_Id)
6223 then
6224 Insert_Action (N,
6225 Make_Raise_Constraint_Error (Loc,
6226 Condition =>
6227 Make_And_Then (Loc,
6228 Left_Opnd =>
6229 Make_Op_Ne (Loc,
6230 Left_Opnd => Duplicate_Subexpr (Exp),
6231 Right_Opnd => Make_Null (Loc)),
6232 Right_Opnd => Make_Op_Ne (Loc,
6233 Left_Opnd =>
6234 Make_Selected_Component (Loc,
6235 Prefix => Duplicate_Subexpr (Exp),
6236 Selector_Name =>
6237 Make_Identifier (Loc, Chars => Name_uTag)),
6238 Right_Opnd =>
6239 Make_Attribute_Reference (Loc,
6240 Prefix =>
6241 New_Occurrence_Of (Designated_Type (R_Type), Loc),
6242 Attribute_Name => Name_Tag))),
6243 Reason => CE_Tag_Check_Failed),
6244 Suppress => All_Checks);
6245 end if;
6246
6247 -- If we are returning an object that may not be bit-aligned, then copy
6248 -- the value into a temporary first. This copy may need to expand to a
6249 -- loop of component operations.
6250
6251 if Is_Possibly_Unaligned_Slice (Exp)
6252 or else Is_Possibly_Unaligned_Object (Exp)
6253 then
6254 declare
6255 ExpR : constant Node_Id := Relocate_Node (Exp);
6256 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
6257 begin
6258 Insert_Action (Exp,
6259 Make_Object_Declaration (Loc,
6260 Defining_Identifier => Tnn,
6261 Constant_Present => True,
6262 Object_Definition => New_Occurrence_Of (R_Type, Loc),
6263 Expression => ExpR),
6264 Suppress => All_Checks);
6265 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
6266 end;
6267 end if;
6268
6269 -- Generate call to postcondition checks if they are present
6270
6271 if Ekind (Scope_Id) = E_Function
6272 and then Has_Postconditions (Scope_Id)
6273 then
6274 -- We are going to reference the returned value twice in this case,
6275 -- once in the call to _Postconditions, and once in the actual return
6276 -- statement, but we can't have side effects happening twice, and in
6277 -- any case for efficiency we don't want to do the computation twice.
6278
6279 -- If the returned expression is an entity name, we don't need to
6280 -- worry since it is efficient and safe to reference it twice, that's
6281 -- also true for literals other than string literals, and for the
6282 -- case of X.all where X is an entity name.
6283
6284 if Is_Entity_Name (Exp)
6285 or else Nkind_In (Exp, N_Character_Literal,
6286 N_Integer_Literal,
6287 N_Real_Literal)
6288 or else (Nkind (Exp) = N_Explicit_Dereference
6289 and then Is_Entity_Name (Prefix (Exp)))
6290 then
6291 null;
6292
6293 -- Otherwise we are going to need a temporary to capture the value
6294
6295 else
6296 declare
6297 ExpR : constant Node_Id := Relocate_Node (Exp);
6298 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR);
6299
6300 begin
6301 -- For a complex expression of an elementary type, capture
6302 -- value in the temporary and use it as the reference.
6303
6304 if Is_Elementary_Type (R_Type) then
6305 Insert_Action (Exp,
6306 Make_Object_Declaration (Loc,
6307 Defining_Identifier => Tnn,
6308 Constant_Present => True,
6309 Object_Definition => New_Occurrence_Of (R_Type, Loc),
6310 Expression => ExpR),
6311 Suppress => All_Checks);
6312
6313 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
6314
6315 -- If we have something we can rename, generate a renaming of
6316 -- the object and replace the expression with a reference
6317
6318 elsif Is_Object_Reference (Exp) then
6319 Insert_Action (Exp,
6320 Make_Object_Renaming_Declaration (Loc,
6321 Defining_Identifier => Tnn,
6322 Subtype_Mark => New_Occurrence_Of (R_Type, Loc),
6323 Name => ExpR),
6324 Suppress => All_Checks);
6325
6326 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
6327
6328 -- Otherwise we have something like a string literal or an
6329 -- aggregate. We could copy the value, but that would be
6330 -- inefficient. Instead we make a reference to the value and
6331 -- capture this reference with a renaming, the expression is
6332 -- then replaced by a dereference of this renaming.
6333
6334 else
6335 -- For now, copy the value, since the code below does not
6336 -- seem to work correctly ???
6337
6338 Insert_Action (Exp,
6339 Make_Object_Declaration (Loc,
6340 Defining_Identifier => Tnn,
6341 Constant_Present => True,
6342 Object_Definition => New_Occurrence_Of (R_Type, Loc),
6343 Expression => Relocate_Node (Exp)),
6344 Suppress => All_Checks);
6345
6346 Rewrite (Exp, New_Occurrence_Of (Tnn, Loc));
6347
6348 -- Insert_Action (Exp,
6349 -- Make_Object_Renaming_Declaration (Loc,
6350 -- Defining_Identifier => Tnn,
6351 -- Access_Definition =>
6352 -- Make_Access_Definition (Loc,
6353 -- All_Present => True,
6354 -- Subtype_Mark => New_Occurrence_Of (R_Type, Loc)),
6355 -- Name =>
6356 -- Make_Reference (Loc,
6357 -- Prefix => Relocate_Node (Exp))),
6358 -- Suppress => All_Checks);
6359
6360 -- Rewrite (Exp,
6361 -- Make_Explicit_Dereference (Loc,
6362 -- Prefix => New_Occurrence_Of (Tnn, Loc)));
6363 end if;
6364 end;
6365 end if;
6366
6367 -- Generate call to _postconditions
6368
6369 Insert_Action (Exp,
6370 Make_Procedure_Call_Statement (Loc,
6371 Name => Make_Identifier (Loc, Name_uPostconditions),
6372 Parameter_Associations => New_List (Duplicate_Subexpr (Exp))));
6373 end if;
6374
6375 -- Ada 2005 (AI-251): If this return statement corresponds with an
6376 -- simple return statement associated with an extended return statement
6377 -- and the type of the returned object is an interface then generate an
6378 -- implicit conversion to force displacement of the "this" pointer.
6379
6380 if Ada_Version >= Ada_2005
6381 and then Comes_From_Extended_Return_Statement (N)
6382 and then Nkind (Expression (N)) = N_Identifier
6383 and then Is_Interface (Utyp)
6384 and then Utyp /= Underlying_Type (Exptyp)
6385 then
6386 Rewrite (Exp, Convert_To (Utyp, Relocate_Node (Exp)));
6387 Analyze_And_Resolve (Exp);
6388 end if;
6389 end Expand_Simple_Function_Return;
6390
6391 --------------------------------
6392 -- Is_Build_In_Place_Function --
6393 --------------------------------
6394
6395 function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is
6396 begin
6397 -- This function is called from Expand_Subtype_From_Expr during
6398 -- semantic analysis, even when expansion is off. In those cases
6399 -- the build_in_place expansion will not take place.
6400
6401 if not Expander_Active then
6402 return False;
6403 end if;
6404
6405 -- For now we test whether E denotes a function or access-to-function
6406 -- type whose result subtype is inherently limited. Later this test may
6407 -- be revised to allow composite nonlimited types. Functions with a
6408 -- foreign convention or whose result type has a foreign convention
6409 -- never qualify.
6410
6411 if Ekind_In (E, E_Function, E_Generic_Function)
6412 or else (Ekind (E) = E_Subprogram_Type
6413 and then Etype (E) /= Standard_Void_Type)
6414 then
6415 -- Note: If you have Convention (C) on an inherently limited type,
6416 -- you're on your own. That is, the C code will have to be carefully
6417 -- written to know about the Ada conventions.
6418
6419 if Has_Foreign_Convention (E)
6420 or else Has_Foreign_Convention (Etype (E))
6421 then
6422 return False;
6423
6424 -- In Ada 2005 all functions with an inherently limited return type
6425 -- must be handled using a build-in-place profile, including the case
6426 -- of a function with a limited interface result, where the function
6427 -- may return objects of nonlimited descendants.
6428
6429 else
6430 return Is_Immutably_Limited_Type (Etype (E))
6431 and then Ada_Version >= Ada_2005
6432 and then not Debug_Flag_Dot_L;
6433 end if;
6434
6435 else
6436 return False;
6437 end if;
6438 end Is_Build_In_Place_Function;
6439
6440 -------------------------------------
6441 -- Is_Build_In_Place_Function_Call --
6442 -------------------------------------
6443
6444 function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is
6445 Exp_Node : Node_Id := N;
6446 Function_Id : Entity_Id;
6447
6448 begin
6449 -- Step past qualification or unchecked conversion (the latter can occur
6450 -- in cases of calls to 'Input).
6451
6452 if Nkind_In
6453 (Exp_Node, N_Qualified_Expression, N_Unchecked_Type_Conversion)
6454 then
6455 Exp_Node := Expression (N);
6456 end if;
6457
6458 if Nkind (Exp_Node) /= N_Function_Call then
6459 return False;
6460
6461 else
6462 if Is_Entity_Name (Name (Exp_Node)) then
6463 Function_Id := Entity (Name (Exp_Node));
6464
6465 elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then
6466 Function_Id := Etype (Name (Exp_Node));
6467 end if;
6468
6469 return Is_Build_In_Place_Function (Function_Id);
6470 end if;
6471 end Is_Build_In_Place_Function_Call;
6472
6473 -----------------------
6474 -- Freeze_Subprogram --
6475 -----------------------
6476
6477 procedure Freeze_Subprogram (N : Node_Id) is
6478 Loc : constant Source_Ptr := Sloc (N);
6479
6480 procedure Register_Predefined_DT_Entry (Prim : Entity_Id);
6481 -- (Ada 2005): Register a predefined primitive in all the secondary
6482 -- dispatch tables of its primitive type.
6483
6484 ----------------------------------
6485 -- Register_Predefined_DT_Entry --
6486 ----------------------------------
6487
6488 procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is
6489 Iface_DT_Ptr : Elmt_Id;
6490 Tagged_Typ : Entity_Id;
6491 Thunk_Id : Entity_Id;
6492 Thunk_Code : Node_Id;
6493
6494 begin
6495 Tagged_Typ := Find_Dispatching_Type (Prim);
6496
6497 if No (Access_Disp_Table (Tagged_Typ))
6498 or else not Has_Interfaces (Tagged_Typ)
6499 or else not RTE_Available (RE_Interface_Tag)
6500 or else Restriction_Active (No_Dispatching_Calls)
6501 then
6502 return;
6503 end if;
6504
6505 -- Skip the first two access-to-dispatch-table pointers since they
6506 -- leads to the primary dispatch table (predefined DT and user
6507 -- defined DT). We are only concerned with the secondary dispatch
6508 -- table pointers. Note that the access-to- dispatch-table pointer
6509 -- corresponds to the first implemented interface retrieved below.
6510
6511 Iface_DT_Ptr :=
6512 Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ))));
6513
6514 while Present (Iface_DT_Ptr)
6515 and then Ekind (Node (Iface_DT_Ptr)) = E_Constant
6516 loop
6517 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
6518 Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code);
6519
6520 if Present (Thunk_Code) then
6521 Insert_Actions_After (N, New_List (
6522 Thunk_Code,
6523
6524 Build_Set_Predefined_Prim_Op_Address (Loc,
6525 Tag_Node =>
6526 New_Reference_To (Node (Next_Elmt (Iface_DT_Ptr)), Loc),
6527 Position => DT_Position (Prim),
6528 Address_Node =>
6529 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
6530 Make_Attribute_Reference (Loc,
6531 Prefix => New_Reference_To (Thunk_Id, Loc),
6532 Attribute_Name => Name_Unrestricted_Access))),
6533
6534 Build_Set_Predefined_Prim_Op_Address (Loc,
6535 Tag_Node =>
6536 New_Reference_To
6537 (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))),
6538 Loc),
6539 Position => DT_Position (Prim),
6540 Address_Node =>
6541 Unchecked_Convert_To (RTE (RE_Prim_Ptr),
6542 Make_Attribute_Reference (Loc,
6543 Prefix => New_Reference_To (Prim, Loc),
6544 Attribute_Name => Name_Unrestricted_Access)))));
6545 end if;
6546
6547 -- Skip the tag of the predefined primitives dispatch table
6548
6549 Next_Elmt (Iface_DT_Ptr);
6550 pragma Assert (Has_Thunks (Node (Iface_DT_Ptr)));
6551
6552 -- Skip the tag of the no-thunks dispatch table
6553
6554 Next_Elmt (Iface_DT_Ptr);
6555 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
6556
6557 -- Skip the tag of the predefined primitives no-thunks dispatch
6558 -- table
6559
6560 Next_Elmt (Iface_DT_Ptr);
6561 pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr)));
6562
6563 Next_Elmt (Iface_DT_Ptr);
6564 end loop;
6565 end Register_Predefined_DT_Entry;
6566
6567 -- Local variables
6568
6569 Subp : constant Entity_Id := Entity (N);
6570
6571 -- Start of processing for Freeze_Subprogram
6572
6573 begin
6574 -- We suppress the initialization of the dispatch table entry when
6575 -- VM_Target because the dispatching mechanism is handled internally
6576 -- by the VM.
6577
6578 if Is_Dispatching_Operation (Subp)
6579 and then not Is_Abstract_Subprogram (Subp)
6580 and then Present (DTC_Entity (Subp))
6581 and then Present (Scope (DTC_Entity (Subp)))
6582 and then Tagged_Type_Expansion
6583 and then not Restriction_Active (No_Dispatching_Calls)
6584 and then RTE_Available (RE_Tag)
6585 then
6586 declare
6587 Typ : constant Entity_Id := Scope (DTC_Entity (Subp));
6588
6589 begin
6590 -- Handle private overridden primitives
6591
6592 if not Is_CPP_Class (Typ) then
6593 Check_Overriding_Operation (Subp);
6594 end if;
6595
6596 -- We assume that imported CPP primitives correspond with objects
6597 -- whose constructor is in the CPP side; therefore we don't need
6598 -- to generate code to register them in the dispatch table.
6599
6600 if Is_CPP_Class (Typ) then
6601 null;
6602
6603 -- Handle CPP primitives found in derivations of CPP_Class types.
6604 -- These primitives must have been inherited from some parent, and
6605 -- there is no need to register them in the dispatch table because
6606 -- Build_Inherit_Prims takes care of the initialization of these
6607 -- slots.
6608
6609 elsif Is_Imported (Subp)
6610 and then (Convention (Subp) = Convention_CPP
6611 or else Convention (Subp) = Convention_C)
6612 then
6613 null;
6614
6615 -- Generate code to register the primitive in non statically
6616 -- allocated dispatch tables
6617
6618 elsif not Building_Static_DT (Scope (DTC_Entity (Subp))) then
6619
6620 -- When a primitive is frozen, enter its name in its dispatch
6621 -- table slot.
6622
6623 if not Is_Interface (Typ)
6624 or else Present (Interface_Alias (Subp))
6625 then
6626 if Is_Predefined_Dispatching_Operation (Subp) then
6627 Register_Predefined_DT_Entry (Subp);
6628 end if;
6629
6630 Insert_Actions_After (N,
6631 Register_Primitive (Loc, Prim => Subp));
6632 end if;
6633 end if;
6634 end;
6635 end if;
6636
6637 -- Mark functions that return by reference. Note that it cannot be part
6638 -- of the normal semantic analysis of the spec since the underlying
6639 -- returned type may not be known yet (for private types).
6640
6641 declare
6642 Typ : constant Entity_Id := Etype (Subp);
6643 Utyp : constant Entity_Id := Underlying_Type (Typ);
6644 begin
6645 if Is_Immutably_Limited_Type (Typ) then
6646 Set_Returns_By_Ref (Subp);
6647 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
6648 Set_Returns_By_Ref (Subp);
6649 end if;
6650 end;
6651 end Freeze_Subprogram;
6652
6653 -----------------------
6654 -- Is_Null_Procedure --
6655 -----------------------
6656
6657 function Is_Null_Procedure (Subp : Entity_Id) return Boolean is
6658 Decl : constant Node_Id := Unit_Declaration_Node (Subp);
6659
6660 begin
6661 if Ekind (Subp) /= E_Procedure then
6662 return False;
6663
6664 -- Check if this is a declared null procedure
6665
6666 elsif Nkind (Decl) = N_Subprogram_Declaration then
6667 if not Null_Present (Specification (Decl)) then
6668 return False;
6669
6670 elsif No (Body_To_Inline (Decl)) then
6671 return False;
6672
6673 -- Check if the body contains only a null statement, followed by
6674 -- the return statement added during expansion.
6675
6676 else
6677 declare
6678 Orig_Bod : constant Node_Id := Body_To_Inline (Decl);
6679
6680 Stat : Node_Id;
6681 Stat2 : Node_Id;
6682
6683 begin
6684 if Nkind (Orig_Bod) /= N_Subprogram_Body then
6685 return False;
6686 else
6687 -- We must skip SCIL nodes because they are currently
6688 -- implemented as special N_Null_Statement nodes.
6689
6690 Stat :=
6691 First_Non_SCIL_Node
6692 (Statements (Handled_Statement_Sequence (Orig_Bod)));
6693 Stat2 := Next_Non_SCIL_Node (Stat);
6694
6695 return
6696 Is_Empty_List (Declarations (Orig_Bod))
6697 and then Nkind (Stat) = N_Null_Statement
6698 and then
6699 (No (Stat2)
6700 or else
6701 (Nkind (Stat2) = N_Simple_Return_Statement
6702 and then No (Next (Stat2))));
6703 end if;
6704 end;
6705 end if;
6706
6707 else
6708 return False;
6709 end if;
6710 end Is_Null_Procedure;
6711
6712 -------------------------------------------
6713 -- Make_Build_In_Place_Call_In_Allocator --
6714 -------------------------------------------
6715
6716 procedure Make_Build_In_Place_Call_In_Allocator
6717 (Allocator : Node_Id;
6718 Function_Call : Node_Id)
6719 is
6720 Loc : Source_Ptr;
6721 Func_Call : Node_Id := Function_Call;
6722 Function_Id : Entity_Id;
6723 Result_Subt : Entity_Id;
6724 Acc_Type : constant Entity_Id := Etype (Allocator);
6725 New_Allocator : Node_Id;
6726 Return_Obj_Access : Entity_Id;
6727
6728 begin
6729 -- Step past qualification or unchecked conversion (the latter can occur
6730 -- in cases of calls to 'Input).
6731
6732 if Nkind_In (Func_Call,
6733 N_Qualified_Expression,
6734 N_Unchecked_Type_Conversion)
6735 then
6736 Func_Call := Expression (Func_Call);
6737 end if;
6738
6739 -- If the call has already been processed to add build-in-place actuals
6740 -- then return. This should not normally occur in an allocator context,
6741 -- but we add the protection as a defensive measure.
6742
6743 if Is_Expanded_Build_In_Place_Call (Func_Call) then
6744 return;
6745 end if;
6746
6747 -- Mark the call as processed as a build-in-place call
6748
6749 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
6750
6751 Loc := Sloc (Function_Call);
6752
6753 if Is_Entity_Name (Name (Func_Call)) then
6754 Function_Id := Entity (Name (Func_Call));
6755
6756 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
6757 Function_Id := Etype (Name (Func_Call));
6758
6759 else
6760 raise Program_Error;
6761 end if;
6762
6763 Result_Subt := Etype (Function_Id);
6764
6765 -- When the result subtype is constrained, the return object must be
6766 -- allocated on the caller side, and access to it is passed to the
6767 -- function.
6768
6769 -- Here and in related routines, we must examine the full view of the
6770 -- type, because the view at the point of call may differ from that
6771 -- that in the function body, and the expansion mechanism depends on
6772 -- the characteristics of the full view.
6773
6774 if Is_Constrained (Underlying_Type (Result_Subt)) then
6775
6776 -- Replace the initialized allocator of form "new T'(Func (...))"
6777 -- with an uninitialized allocator of form "new T", where T is the
6778 -- result subtype of the called function. The call to the function
6779 -- is handled separately further below.
6780
6781 New_Allocator :=
6782 Make_Allocator (Loc,
6783 Expression => New_Reference_To (Result_Subt, Loc));
6784 Set_No_Initialization (New_Allocator);
6785
6786 -- Copy attributes to new allocator. Note that the new allocator
6787 -- logically comes from source if the original one did, so copy the
6788 -- relevant flag. This ensures proper treatment of the restriction
6789 -- No_Implicit_Heap_Allocations in this case.
6790
6791 Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator));
6792 Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator));
6793 Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator));
6794
6795 Rewrite (Allocator, New_Allocator);
6796
6797 -- Create a new access object and initialize it to the result of the
6798 -- new uninitialized allocator. Note: we do not use Allocator as the
6799 -- Related_Node of Return_Obj_Access in call to Make_Temporary below
6800 -- as this would create a sort of infinite "recursion".
6801
6802 Return_Obj_Access := Make_Temporary (Loc, 'R');
6803 Set_Etype (Return_Obj_Access, Acc_Type);
6804
6805 Insert_Action (Allocator,
6806 Make_Object_Declaration (Loc,
6807 Defining_Identifier => Return_Obj_Access,
6808 Object_Definition => New_Reference_To (Acc_Type, Loc),
6809 Expression => Relocate_Node (Allocator)));
6810
6811 -- When the function has a controlling result, an allocation-form
6812 -- parameter must be passed indicating that the caller is allocating
6813 -- the result object. This is needed because such a function can be
6814 -- called as a dispatching operation and must be treated similarly
6815 -- to functions with unconstrained result subtypes.
6816
6817 Add_Alloc_Form_Actual_To_Build_In_Place_Call
6818 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
6819
6820 Add_Final_List_Actual_To_Build_In_Place_Call
6821 (Func_Call, Function_Id, Acc_Type);
6822
6823 Add_Task_Actuals_To_Build_In_Place_Call
6824 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
6825
6826 -- Add an implicit actual to the function call that provides access
6827 -- to the allocated object. An unchecked conversion to the (specific)
6828 -- result subtype of the function is inserted to handle cases where
6829 -- the access type of the allocator has a class-wide designated type.
6830
6831 Add_Access_Actual_To_Build_In_Place_Call
6832 (Func_Call,
6833 Function_Id,
6834 Make_Unchecked_Type_Conversion (Loc,
6835 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
6836 Expression =>
6837 Make_Explicit_Dereference (Loc,
6838 Prefix => New_Reference_To (Return_Obj_Access, Loc))));
6839
6840 -- When the result subtype is unconstrained, the function itself must
6841 -- perform the allocation of the return object, so we pass parameters
6842 -- indicating that. We don't yet handle the case where the allocation
6843 -- must be done in a user-defined storage pool, which will require
6844 -- passing another actual or two to provide allocation/deallocation
6845 -- operations. ???
6846
6847 else
6848
6849 -- Pass an allocation parameter indicating that the function should
6850 -- allocate its result on the heap.
6851
6852 Add_Alloc_Form_Actual_To_Build_In_Place_Call
6853 (Func_Call, Function_Id, Alloc_Form => Global_Heap);
6854
6855 Add_Final_List_Actual_To_Build_In_Place_Call
6856 (Func_Call, Function_Id, Acc_Type);
6857
6858 Add_Task_Actuals_To_Build_In_Place_Call
6859 (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type));
6860
6861 -- The caller does not provide the return object in this case, so we
6862 -- have to pass null for the object access actual.
6863
6864 Add_Access_Actual_To_Build_In_Place_Call
6865 (Func_Call, Function_Id, Return_Object => Empty);
6866 end if;
6867
6868 -- Finally, replace the allocator node with a reference to the result
6869 -- of the function call itself (which will effectively be an access
6870 -- to the object created by the allocator).
6871
6872 Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call)));
6873 Analyze_And_Resolve (Allocator, Acc_Type);
6874 end Make_Build_In_Place_Call_In_Allocator;
6875
6876 ---------------------------------------------------
6877 -- Make_Build_In_Place_Call_In_Anonymous_Context --
6878 ---------------------------------------------------
6879
6880 procedure Make_Build_In_Place_Call_In_Anonymous_Context
6881 (Function_Call : Node_Id)
6882 is
6883 Loc : Source_Ptr;
6884 Func_Call : Node_Id := Function_Call;
6885 Function_Id : Entity_Id;
6886 Result_Subt : Entity_Id;
6887 Return_Obj_Id : Entity_Id;
6888 Return_Obj_Decl : Entity_Id;
6889
6890 begin
6891 -- Step past qualification or unchecked conversion (the latter can occur
6892 -- in cases of calls to 'Input).
6893
6894 if Nkind_In (Func_Call, N_Qualified_Expression,
6895 N_Unchecked_Type_Conversion)
6896 then
6897 Func_Call := Expression (Func_Call);
6898 end if;
6899
6900 -- If the call has already been processed to add build-in-place actuals
6901 -- then return. One place this can occur is for calls to build-in-place
6902 -- functions that occur within a call to a protected operation, where
6903 -- due to rewriting and expansion of the protected call there can be
6904 -- more than one call to Expand_Actuals for the same set of actuals.
6905
6906 if Is_Expanded_Build_In_Place_Call (Func_Call) then
6907 return;
6908 end if;
6909
6910 -- Mark the call as processed as a build-in-place call
6911
6912 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
6913
6914 Loc := Sloc (Function_Call);
6915
6916 if Is_Entity_Name (Name (Func_Call)) then
6917 Function_Id := Entity (Name (Func_Call));
6918
6919 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
6920 Function_Id := Etype (Name (Func_Call));
6921
6922 else
6923 raise Program_Error;
6924 end if;
6925
6926 Result_Subt := Etype (Function_Id);
6927
6928 -- When the result subtype is constrained, an object of the subtype is
6929 -- declared and an access value designating it is passed as an actual.
6930
6931 if Is_Constrained (Underlying_Type (Result_Subt)) then
6932
6933 -- Create a temporary object to hold the function result
6934
6935 Return_Obj_Id := Make_Temporary (Loc, 'R');
6936 Set_Etype (Return_Obj_Id, Result_Subt);
6937
6938 Return_Obj_Decl :=
6939 Make_Object_Declaration (Loc,
6940 Defining_Identifier => Return_Obj_Id,
6941 Aliased_Present => True,
6942 Object_Definition => New_Reference_To (Result_Subt, Loc));
6943
6944 Set_No_Initialization (Return_Obj_Decl);
6945
6946 Insert_Action (Func_Call, Return_Obj_Decl);
6947
6948 -- When the function has a controlling result, an allocation-form
6949 -- parameter must be passed indicating that the caller is allocating
6950 -- the result object. This is needed because such a function can be
6951 -- called as a dispatching operation and must be treated similarly
6952 -- to functions with unconstrained result subtypes.
6953
6954 Add_Alloc_Form_Actual_To_Build_In_Place_Call
6955 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
6956
6957 Add_Final_List_Actual_To_Build_In_Place_Call
6958 (Func_Call, Function_Id, Acc_Type => Empty);
6959
6960 Add_Task_Actuals_To_Build_In_Place_Call
6961 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
6962
6963 -- Add an implicit actual to the function call that provides access
6964 -- to the caller's return object.
6965
6966 Add_Access_Actual_To_Build_In_Place_Call
6967 (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc));
6968
6969 -- When the result subtype is unconstrained, the function must allocate
6970 -- the return object in the secondary stack, so appropriate implicit
6971 -- parameters are added to the call to indicate that. A transient
6972 -- scope is established to ensure eventual cleanup of the result.
6973
6974 else
6975 -- Pass an allocation parameter indicating that the function should
6976 -- allocate its result on the secondary stack.
6977
6978 Add_Alloc_Form_Actual_To_Build_In_Place_Call
6979 (Func_Call, Function_Id, Alloc_Form => Secondary_Stack);
6980
6981 Add_Final_List_Actual_To_Build_In_Place_Call
6982 (Func_Call, Function_Id, Acc_Type => Empty);
6983
6984 Add_Task_Actuals_To_Build_In_Place_Call
6985 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
6986
6987 -- Pass a null value to the function since no return object is
6988 -- available on the caller side.
6989
6990 Add_Access_Actual_To_Build_In_Place_Call
6991 (Func_Call, Function_Id, Empty);
6992 end if;
6993 end Make_Build_In_Place_Call_In_Anonymous_Context;
6994
6995 --------------------------------------------
6996 -- Make_Build_In_Place_Call_In_Assignment --
6997 --------------------------------------------
6998
6999 procedure Make_Build_In_Place_Call_In_Assignment
7000 (Assign : Node_Id;
7001 Function_Call : Node_Id)
7002 is
7003 Lhs : constant Node_Id := Name (Assign);
7004 Func_Call : Node_Id := Function_Call;
7005 Func_Id : Entity_Id;
7006 Loc : Source_Ptr;
7007 Obj_Decl : Node_Id;
7008 Obj_Id : Entity_Id;
7009 Ptr_Typ : Entity_Id;
7010 Ptr_Typ_Decl : Node_Id;
7011 Result_Subt : Entity_Id;
7012 Target : Node_Id;
7013
7014 begin
7015 -- Step past qualification or unchecked conversion (the latter can occur
7016 -- in cases of calls to 'Input).
7017
7018 if Nkind_In (Func_Call, N_Qualified_Expression,
7019 N_Unchecked_Type_Conversion)
7020 then
7021 Func_Call := Expression (Func_Call);
7022 end if;
7023
7024 -- If the call has already been processed to add build-in-place actuals
7025 -- then return. This should not normally occur in an assignment context,
7026 -- but we add the protection as a defensive measure.
7027
7028 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7029 return;
7030 end if;
7031
7032 -- Mark the call as processed as a build-in-place call
7033
7034 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7035
7036 Loc := Sloc (Function_Call);
7037
7038 if Is_Entity_Name (Name (Func_Call)) then
7039 Func_Id := Entity (Name (Func_Call));
7040
7041 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7042 Func_Id := Etype (Name (Func_Call));
7043
7044 else
7045 raise Program_Error;
7046 end if;
7047
7048 Result_Subt := Etype (Func_Id);
7049
7050 -- When the result subtype is unconstrained, an additional actual must
7051 -- be passed to indicate that the caller is providing the return object.
7052 -- This parameter must also be passed when the called function has a
7053 -- controlling result, because dispatching calls to the function needs
7054 -- to be treated effectively the same as calls to class-wide functions.
7055
7056 Add_Alloc_Form_Actual_To_Build_In_Place_Call
7057 (Func_Call, Func_Id, Alloc_Form => Caller_Allocation);
7058
7059 -- If Lhs is a selected component, then pass it along so that its prefix
7060 -- object will be used as the source of the finalization list.
7061
7062 if Nkind (Lhs) = N_Selected_Component then
7063 Add_Final_List_Actual_To_Build_In_Place_Call
7064 (Func_Call, Func_Id, Acc_Type => Empty, Sel_Comp => Lhs);
7065 else
7066 Add_Final_List_Actual_To_Build_In_Place_Call
7067 (Func_Call, Func_Id, Acc_Type => Empty);
7068 end if;
7069
7070 Add_Task_Actuals_To_Build_In_Place_Call
7071 (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster));
7072
7073 -- Add an implicit actual to the function call that provides access to
7074 -- the caller's return object.
7075
7076 Add_Access_Actual_To_Build_In_Place_Call
7077 (Func_Call,
7078 Func_Id,
7079 Make_Unchecked_Type_Conversion (Loc,
7080 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
7081 Expression => Relocate_Node (Lhs)));
7082
7083 -- Create an access type designating the function's result subtype
7084
7085 Ptr_Typ := Make_Temporary (Loc, 'A');
7086
7087 Ptr_Typ_Decl :=
7088 Make_Full_Type_Declaration (Loc,
7089 Defining_Identifier => Ptr_Typ,
7090 Type_Definition =>
7091 Make_Access_To_Object_Definition (Loc,
7092 All_Present => True,
7093 Subtype_Indication =>
7094 New_Reference_To (Result_Subt, Loc)));
7095 Insert_After_And_Analyze (Assign, Ptr_Typ_Decl);
7096
7097 -- Finally, create an access object initialized to a reference to the
7098 -- function call.
7099
7100 Obj_Id := Make_Temporary (Loc, 'R');
7101 Set_Etype (Obj_Id, Ptr_Typ);
7102
7103 Obj_Decl :=
7104 Make_Object_Declaration (Loc,
7105 Defining_Identifier => Obj_Id,
7106 Object_Definition =>
7107 New_Reference_To (Ptr_Typ, Loc),
7108 Expression =>
7109 Make_Reference (Loc,
7110 Prefix => Relocate_Node (Func_Call)));
7111 Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl);
7112
7113 Rewrite (Assign, Make_Null_Statement (Loc));
7114
7115 -- Retrieve the target of the assignment
7116
7117 if Nkind (Lhs) = N_Selected_Component then
7118 Target := Selector_Name (Lhs);
7119 elsif Nkind (Lhs) = N_Type_Conversion then
7120 Target := Expression (Lhs);
7121 else
7122 Target := Lhs;
7123 end if;
7124
7125 -- If we are assigning to a return object or this is an expression of
7126 -- an extension aggregate, the target should either be an identifier
7127 -- or a simple expression. All other cases imply a different scenario.
7128
7129 if Nkind (Target) in N_Has_Entity then
7130 Target := Entity (Target);
7131 else
7132 return;
7133 end if;
7134
7135 -- When the target of the assignment is a return object of an enclosing
7136 -- build-in-place function and also requires finalization, the list
7137 -- generated for the assignment must be moved to that of the enclosing
7138 -- function.
7139
7140 -- function Enclosing_BIP_Function return Ctrl_Typ is
7141 -- begin
7142 -- return (Ctrl_Parent_Part => BIP_Function with ...);
7143 -- end Enclosing_BIP_Function;
7144
7145 if Is_Return_Object (Target)
7146 and then Needs_Finalization (Etype (Target))
7147 and then Needs_Finalization (Result_Subt)
7148 then
7149 declare
7150 Obj_List : constant Node_Id := Find_Final_List (Obj_Id);
7151 Encl_List : Node_Id;
7152 Encl_Scop : Entity_Id;
7153
7154 begin
7155 Encl_Scop := Scope (Target);
7156
7157 -- Locate the scope of the extended return statement
7158
7159 while Present (Encl_Scop)
7160 and then Ekind (Encl_Scop) /= E_Return_Statement
7161 loop
7162 Encl_Scop := Scope (Encl_Scop);
7163 end loop;
7164
7165 -- A return object should always be enclosed by a return statement
7166 -- scope at some level.
7167
7168 pragma Assert (Present (Encl_Scop));
7169
7170 Encl_List :=
7171 Make_Attribute_Reference (Loc,
7172 Prefix =>
7173 New_Reference_To (
7174 Finalization_Chain_Entity (Encl_Scop), Loc),
7175 Attribute_Name => Name_Unrestricted_Access);
7176
7177 -- Generate a call to move final list
7178
7179 Insert_After_And_Analyze (Obj_Decl,
7180 Make_Procedure_Call_Statement (Loc,
7181 Name =>
7182 New_Reference_To (RTE (RE_Move_Final_List), Loc),
7183 Parameter_Associations => New_List (Obj_List, Encl_List)));
7184 end;
7185 end if;
7186 end Make_Build_In_Place_Call_In_Assignment;
7187
7188 ----------------------------------------------------
7189 -- Make_Build_In_Place_Call_In_Object_Declaration --
7190 ----------------------------------------------------
7191
7192 procedure Make_Build_In_Place_Call_In_Object_Declaration
7193 (Object_Decl : Node_Id;
7194 Function_Call : Node_Id)
7195 is
7196 Loc : Source_Ptr;
7197 Obj_Def_Id : constant Entity_Id :=
7198 Defining_Identifier (Object_Decl);
7199
7200 Func_Call : Node_Id := Function_Call;
7201 Function_Id : Entity_Id;
7202 Result_Subt : Entity_Id;
7203 Caller_Object : Node_Id;
7204 Call_Deref : Node_Id;
7205 Ref_Type : Entity_Id;
7206 Ptr_Typ_Decl : Node_Id;
7207 Def_Id : Entity_Id;
7208 New_Expr : Node_Id;
7209 Enclosing_Func : Entity_Id;
7210 Pass_Caller_Acc : Boolean := False;
7211
7212 begin
7213 -- Step past qualification or unchecked conversion (the latter can occur
7214 -- in cases of calls to 'Input).
7215
7216 if Nkind_In (Func_Call, N_Qualified_Expression,
7217 N_Unchecked_Type_Conversion)
7218 then
7219 Func_Call := Expression (Func_Call);
7220 end if;
7221
7222 -- If the call has already been processed to add build-in-place actuals
7223 -- then return. This should not normally occur in an object declaration,
7224 -- but we add the protection as a defensive measure.
7225
7226 if Is_Expanded_Build_In_Place_Call (Func_Call) then
7227 return;
7228 end if;
7229
7230 -- Mark the call as processed as a build-in-place call
7231
7232 Set_Is_Expanded_Build_In_Place_Call (Func_Call);
7233
7234 Loc := Sloc (Function_Call);
7235
7236 if Is_Entity_Name (Name (Func_Call)) then
7237 Function_Id := Entity (Name (Func_Call));
7238
7239 elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then
7240 Function_Id := Etype (Name (Func_Call));
7241
7242 else
7243 raise Program_Error;
7244 end if;
7245
7246 Result_Subt := Etype (Function_Id);
7247
7248 -- In the constrained case, add an implicit actual to the function call
7249 -- that provides access to the declared object. An unchecked conversion
7250 -- to the (specific) result type of the function is inserted to handle
7251 -- the case where the object is declared with a class-wide type.
7252
7253 if Is_Constrained (Underlying_Type (Result_Subt)) then
7254 Caller_Object :=
7255 Make_Unchecked_Type_Conversion (Loc,
7256 Subtype_Mark => New_Reference_To (Result_Subt, Loc),
7257 Expression => New_Reference_To (Obj_Def_Id, Loc));
7258
7259 -- When the function has a controlling result, an allocation-form
7260 -- parameter must be passed indicating that the caller is allocating
7261 -- the result object. This is needed because such a function can be
7262 -- called as a dispatching operation and must be treated similarly
7263 -- to functions with unconstrained result subtypes.
7264
7265 Add_Alloc_Form_Actual_To_Build_In_Place_Call
7266 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7267
7268 -- If the function's result subtype is unconstrained and the object is
7269 -- a return object of an enclosing build-in-place function, then the
7270 -- implicit build-in-place parameters of the enclosing function must be
7271 -- passed along to the called function. (Unfortunately, this won't cover
7272 -- the case of extension aggregates where the ancestor part is a build-
7273 -- in-place unconstrained function call that should be passed along the
7274 -- caller's parameters. Currently those get mishandled by reassigning
7275 -- the result of the call to the aggregate return object, when the call
7276 -- result should really be directly built in place in the aggregate and
7277 -- not built in a temporary. ???)
7278
7279 elsif Is_Return_Object (Defining_Identifier (Object_Decl)) then
7280 Pass_Caller_Acc := True;
7281
7282 Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id);
7283
7284 -- If the enclosing function has a constrained result type, then
7285 -- caller allocation will be used.
7286
7287 if Is_Constrained (Etype (Enclosing_Func)) then
7288 Add_Alloc_Form_Actual_To_Build_In_Place_Call
7289 (Func_Call, Function_Id, Alloc_Form => Caller_Allocation);
7290
7291 -- Otherwise, when the enclosing function has an unconstrained result
7292 -- type, the BIP_Alloc_Form formal of the enclosing function must be
7293 -- passed along to the callee.
7294
7295 else
7296 Add_Alloc_Form_Actual_To_Build_In_Place_Call
7297 (Func_Call,
7298 Function_Id,
7299 Alloc_Form_Exp =>
7300 New_Reference_To
7301 (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form),
7302 Loc));
7303 end if;
7304
7305 -- Retrieve the BIPacc formal from the enclosing function and convert
7306 -- it to the access type of the callee's BIP_Object_Access formal.
7307
7308 Caller_Object :=
7309 Make_Unchecked_Type_Conversion (Loc,
7310 Subtype_Mark =>
7311 New_Reference_To
7312 (Etype
7313 (Build_In_Place_Formal (Function_Id, BIP_Object_Access)),
7314 Loc),
7315 Expression =>
7316 New_Reference_To
7317 (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access),
7318 Loc));
7319
7320 -- In other unconstrained cases, pass an indication to do the allocation
7321 -- on the secondary stack and set Caller_Object to Empty so that a null
7322 -- value will be passed for the caller's object address. A transient
7323 -- scope is established to ensure eventual cleanup of the result.
7324
7325 else
7326 Add_Alloc_Form_Actual_To_Build_In_Place_Call
7327 (Func_Call,
7328 Function_Id,
7329 Alloc_Form => Secondary_Stack);
7330 Caller_Object := Empty;
7331
7332 Establish_Transient_Scope (Object_Decl, Sec_Stack => True);
7333 end if;
7334
7335 Add_Final_List_Actual_To_Build_In_Place_Call
7336 (Func_Call, Function_Id, Acc_Type => Empty);
7337
7338 if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement
7339 and then Has_Task (Result_Subt)
7340 then
7341 Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id);
7342
7343 -- Here we're passing along the master that was passed in to this
7344 -- function.
7345
7346 Add_Task_Actuals_To_Build_In_Place_Call
7347 (Func_Call, Function_Id,
7348 Master_Actual =>
7349 New_Reference_To
7350 (Build_In_Place_Formal (Enclosing_Func, BIP_Master), Loc));
7351
7352 else
7353 Add_Task_Actuals_To_Build_In_Place_Call
7354 (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster));
7355 end if;
7356
7357 Add_Access_Actual_To_Build_In_Place_Call
7358 (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc);
7359
7360 -- Create an access type designating the function's result subtype. We
7361 -- use the type of the original expression because it may be a call to
7362 -- an inherited operation, which the expansion has replaced with the
7363 -- parent operation that yields the parent type.
7364
7365 Ref_Type := Make_Temporary (Loc, 'A');
7366
7367 Ptr_Typ_Decl :=
7368 Make_Full_Type_Declaration (Loc,
7369 Defining_Identifier => Ref_Type,
7370 Type_Definition =>
7371 Make_Access_To_Object_Definition (Loc,
7372 All_Present => True,
7373 Subtype_Indication =>
7374 New_Reference_To (Etype (Function_Call), Loc)));
7375
7376 -- The access type and its accompanying object must be inserted after
7377 -- the object declaration in the constrained case, so that the function
7378 -- call can be passed access to the object. In the unconstrained case,
7379 -- the access type and object must be inserted before the object, since
7380 -- the object declaration is rewritten to be a renaming of a dereference
7381 -- of the access object.
7382
7383 if Is_Constrained (Underlying_Type (Result_Subt)) then
7384 Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl);
7385 else
7386 Insert_Action (Object_Decl, Ptr_Typ_Decl);
7387 end if;
7388
7389 -- Finally, create an access object initialized to a reference to the
7390 -- function call.
7391
7392 New_Expr :=
7393 Make_Reference (Loc,
7394 Prefix => Relocate_Node (Func_Call));
7395
7396 Def_Id := Make_Temporary (Loc, 'R', New_Expr);
7397 Set_Etype (Def_Id, Ref_Type);
7398
7399 Insert_After_And_Analyze (Ptr_Typ_Decl,
7400 Make_Object_Declaration (Loc,
7401 Defining_Identifier => Def_Id,
7402 Object_Definition => New_Reference_To (Ref_Type, Loc),
7403 Expression => New_Expr));
7404
7405 if Is_Constrained (Underlying_Type (Result_Subt)) then
7406 Set_Expression (Object_Decl, Empty);
7407 Set_No_Initialization (Object_Decl);
7408
7409 -- In case of an unconstrained result subtype, rewrite the object
7410 -- declaration as an object renaming where the renamed object is a
7411 -- dereference of <function_Call>'reference:
7412 --
7413 -- Obj : Subt renames <function_call>'Ref.all;
7414
7415 else
7416 Call_Deref :=
7417 Make_Explicit_Dereference (Loc,
7418 Prefix => New_Reference_To (Def_Id, Loc));
7419
7420 Loc := Sloc (Object_Decl);
7421 Rewrite (Object_Decl,
7422 Make_Object_Renaming_Declaration (Loc,
7423 Defining_Identifier => Make_Temporary (Loc, 'D'),
7424 Access_Definition => Empty,
7425 Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc),
7426 Name => Call_Deref));
7427
7428 Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref);
7429
7430 Analyze (Object_Decl);
7431
7432 -- Replace the internal identifier of the renaming declaration's
7433 -- entity with identifier of the original object entity. We also have
7434 -- to exchange the entities containing their defining identifiers to
7435 -- ensure the correct replacement of the object declaration by the
7436 -- object renaming declaration to avoid homograph conflicts (since
7437 -- the object declaration's defining identifier was already entered
7438 -- in current scope). The Next_Entity links of the two entities also
7439 -- have to be swapped since the entities are part of the return
7440 -- scope's entity list and the list structure would otherwise be
7441 -- corrupted. Finally, the homonym chain must be preserved as well.
7442
7443 declare
7444 Renaming_Def_Id : constant Entity_Id :=
7445 Defining_Identifier (Object_Decl);
7446 Next_Entity_Temp : constant Entity_Id :=
7447 Next_Entity (Renaming_Def_Id);
7448 begin
7449 Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id));
7450
7451 -- Swap next entity links in preparation for exchanging entities
7452
7453 Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id));
7454 Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp);
7455 Set_Homonym (Renaming_Def_Id, Homonym (Obj_Def_Id));
7456
7457 Exchange_Entities (Renaming_Def_Id, Obj_Def_Id);
7458
7459 -- Preserve source indication of original declaration, so that
7460 -- xref information is properly generated for the right entity.
7461
7462 Preserve_Comes_From_Source
7463 (Object_Decl, Original_Node (Object_Decl));
7464 Set_Comes_From_Source (Obj_Def_Id, True);
7465 Set_Comes_From_Source (Renaming_Def_Id, False);
7466 end;
7467 end if;
7468
7469 -- If the object entity has a class-wide Etype, then we need to change
7470 -- it to the result subtype of the function call, because otherwise the
7471 -- object will be class-wide without an explicit initialization and
7472 -- won't be allocated properly by the back end. It seems unclean to make
7473 -- such a revision to the type at this point, and we should try to
7474 -- improve this treatment when build-in-place functions with class-wide
7475 -- results are implemented. ???
7476
7477 if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then
7478 Set_Etype (Defining_Identifier (Object_Decl), Result_Subt);
7479 end if;
7480 end Make_Build_In_Place_Call_In_Object_Declaration;
7481
7482 --------------------------
7483 -- Needs_BIP_Final_List --
7484 --------------------------
7485
7486 function Needs_BIP_Final_List (E : Entity_Id) return Boolean is
7487 pragma Assert (Is_Build_In_Place_Function (E));
7488 Result_Subt : constant Entity_Id := Underlying_Type (Etype (E));
7489
7490 begin
7491 -- We need the BIP_Final_List if the result type needs finalization. We
7492 -- also need it for tagged types, even if not class-wide, because some
7493 -- type extension might need finalization, and all overriding functions
7494 -- must have the same calling conventions. However, if there is a
7495 -- pragma Restrictions (No_Finalization), we never need this parameter.
7496
7497 return (Needs_Finalization (Result_Subt)
7498 or else Is_Tagged_Type (Underlying_Type (Result_Subt)))
7499 and then not Restriction_Active (No_Finalization);
7500 end Needs_BIP_Final_List;
7501
7502 end Exp_Ch6;