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1 281 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT COMPILER COMPONENTS                         --
4
--                                                                          --
5
--                             E X P _ I N T R                              --
6
--                                                                          --
7
--                                 B o d y                                  --
8
--                                                                          --
9
--          Copyright (C) 1992-2009, 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 Einfo;    use Einfo;
29
with Elists;   use Elists;
30
with Errout;   use Errout;
31
with Exp_Atag; use Exp_Atag;
32
with Exp_Ch4;  use Exp_Ch4;
33
with Exp_Ch7;  use Exp_Ch7;
34
with Exp_Ch11; use Exp_Ch11;
35
with Exp_Code; use Exp_Code;
36
with Exp_Fixd; use Exp_Fixd;
37
with Exp_Util; use Exp_Util;
38
with Freeze;   use Freeze;
39
with Namet;    use Namet;
40
with Nmake;    use Nmake;
41
with Nlists;   use Nlists;
42
with Opt;      use Opt;
43
with Restrict; use Restrict;
44
with Rident;   use Rident;
45
with Rtsfind;  use Rtsfind;
46
with Sem;      use Sem;
47
with Sem_Eval; use Sem_Eval;
48
with Sem_Res;  use Sem_Res;
49
with Sem_Type; use Sem_Type;
50
with Sem_Util; use Sem_Util;
51
with Sinfo;    use Sinfo;
52
with Sinput;   use Sinput;
53
with Snames;   use Snames;
54
with Stand;    use Stand;
55
with Stringt;  use Stringt;
56
with Tbuild;   use Tbuild;
57
with Uintp;    use Uintp;
58
with Urealp;   use Urealp;
59
 
60
package body Exp_Intr is
61
 
62
   -----------------------
63
   -- Local Subprograms --
64
   -----------------------
65
 
66
   procedure Expand_Is_Negative (N : Node_Id);
67
   --  Expand a call to the intrinsic Is_Negative function
68
 
69
   procedure Expand_Dispatching_Constructor_Call (N : Node_Id);
70
   --  Expand a call to an instantiation of Generic_Dispatching_Constructor
71
   --  into a dispatching call to the actual subprogram associated with the
72
   --  Constructor formal subprogram, passing it the Parameters actual of
73
   --  the call to the instantiation and dispatching based on call's Tag
74
   --  parameter.
75
 
76
   procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id);
77
   --  Expand a call to Exception_Information/Message/Name. The first
78
   --  parameter, N, is the node for the function call, and Ent is the
79
   --  entity for the corresponding routine in the Ada.Exceptions package.
80
 
81
   procedure Expand_Import_Call (N : Node_Id);
82
   --  Expand a call to Import_Address/Longest_Integer/Value. The parameter
83
   --  N is the node for the function call.
84
 
85
   procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind);
86
   --  Expand an intrinsic shift operation, N and E are from the call to
87
   --  Expand_Intrinsic_Call (call node and subprogram spec entity) and
88
   --  K is the kind for the shift node
89
 
90
   procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id);
91
   --  Expand a call to an instantiation of Unchecked_Conversion into a node
92
   --  N_Unchecked_Type_Conversion.
93
 
94
   procedure Expand_Unc_Deallocation (N : Node_Id);
95
   --  Expand a call to an instantiation of Unchecked_Deallocation into a node
96
   --  N_Free_Statement and appropriate context.
97
 
98
   procedure Expand_To_Address (N : Node_Id);
99
   procedure Expand_To_Pointer (N : Node_Id);
100
   --  Expand a call to corresponding function, declared in an instance of
101
   --  System.Address_To_Access_Conversions.
102
 
103
   procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id);
104
   --  Rewrite the node by the appropriate string or positive constant.
105
   --  Nam can be one of the following:
106
   --    Name_File             - expand string that is the name of source file
107
   --    Name_Line             - expand integer line number
108
   --    Name_Source_Location  - expand string of form file:line
109
   --    Name_Enclosing_Entity - expand string  with name of enclosing entity
110
 
111
   -----------------------------------------
112
   -- Expand_Dispatching_Constructor_Call --
113
   -----------------------------------------
114
 
115
   --  Transform a call to an instantiation of Generic_Dispatching_Constructor
116
   --  of the form:
117
 
118
   --     GDC_Instance (The_Tag, Parameters'Access)
119
 
120
   --  to a class-wide conversion of a dispatching call to the actual
121
   --  associated with the formal subprogram Construct, designating The_Tag
122
   --  as the controlling tag of the call:
123
 
124
   --     T'Class (Construct'Actual (Params)) -- Controlling tag is The_Tag
125
 
126
   --  which will eventually be expanded to the following:
127
 
128
   --     T'Class (The_Tag.all (Construct'Actual'Index).all (Params))
129
 
130
   --  A class-wide membership test is also generated, preceding the call, to
131
   --  ensure that the controlling tag denotes a type in T'Class.
132
 
133
   procedure Expand_Dispatching_Constructor_Call (N : Node_Id) is
134
      Loc        : constant Source_Ptr := Sloc (N);
135
      Tag_Arg    : constant Node_Id    := First_Actual (N);
136
      Param_Arg  : constant Node_Id    := Next_Actual (Tag_Arg);
137
      Subp_Decl  : constant Node_Id    := Parent (Parent (Entity (Name (N))));
138
      Inst_Pkg   : constant Node_Id    := Parent (Subp_Decl);
139
      Act_Rename : Node_Id;
140
      Act_Constr : Entity_Id;
141
      Iface_Tag  : Node_Id := Empty;
142
      Cnstr_Call : Node_Id;
143
      Result_Typ : Entity_Id;
144
 
145
   begin
146
      --  The subprogram is the third actual in the instantiation, and is
147
      --  retrieved from the corresponding renaming declaration. However,
148
      --  freeze nodes may appear before, so we retrieve the declaration
149
      --  with an explicit loop.
150
 
151
      Act_Rename := First (Visible_Declarations (Inst_Pkg));
152
      while Nkind (Act_Rename) /= N_Subprogram_Renaming_Declaration loop
153
         Next (Act_Rename);
154
      end loop;
155
 
156
      Act_Constr := Entity (Name (Act_Rename));
157
      Result_Typ := Class_Wide_Type (Etype (Act_Constr));
158
 
159
      --  Ada 2005 (AI-251): If the result is an interface type, the function
160
      --  returns a class-wide interface type (otherwise the resulting object
161
      --  would be abstract!)
162
 
163
      if Is_Interface (Etype (Act_Constr)) then
164
         Set_Etype (Act_Constr, Result_Typ);
165
 
166
         --  If the result type is not parent of Tag_Arg then we need to
167
         --  locate the tag of the secondary dispatch table.
168
 
169
         if not Is_Ancestor (Etype (Result_Typ), Etype (Tag_Arg)) then
170
            pragma Assert (not Is_Interface (Etype (Tag_Arg)));
171
 
172
            Iface_Tag :=
173
              Make_Object_Declaration (Loc,
174
                Defining_Identifier =>
175
                  Make_Defining_Identifier (Loc, New_Internal_Name ('V')),
176
                Object_Definition =>
177
                  New_Reference_To (RTE (RE_Tag), Loc),
178
                Expression =>
179
                  Make_Function_Call (Loc,
180
                    Name => New_Reference_To (RTE (RE_Secondary_Tag), Loc),
181
                    Parameter_Associations => New_List (
182
                      Relocate_Node (Tag_Arg),
183
                      New_Reference_To
184
                        (Node (First_Elmt (Access_Disp_Table
185
                                            (Etype (Etype (Act_Constr))))),
186
                         Loc))));
187
            Insert_Action (N, Iface_Tag);
188
         end if;
189
      end if;
190
 
191
      --  Create the call to the actual Constructor function
192
 
193
      Cnstr_Call :=
194
        Make_Function_Call (Loc,
195
          Name                   => New_Occurrence_Of (Act_Constr, Loc),
196
          Parameter_Associations => New_List (Relocate_Node (Param_Arg)));
197
 
198
      --  Establish its controlling tag from the tag passed to the instance
199
      --  The tag may be given by a function call, in which case a temporary
200
      --  should be generated now, to prevent out-of-order insertions during
201
      --  the expansion of that call when stack-checking is enabled.
202
 
203
      if Present (Iface_Tag) then
204
         Set_Controlling_Argument (Cnstr_Call,
205
           New_Occurrence_Of (Defining_Identifier (Iface_Tag), Loc));
206
      else
207
         Remove_Side_Effects (Tag_Arg);
208
         Set_Controlling_Argument (Cnstr_Call,
209
           Relocate_Node (Tag_Arg));
210
      end if;
211
 
212
      --  Rewrite and analyze the call to the instance as a class-wide
213
      --  conversion of the call to the actual constructor.
214
 
215
      Rewrite (N, Convert_To (Result_Typ, Cnstr_Call));
216
      Analyze_And_Resolve (N, Etype (Act_Constr));
217
 
218
      --  Do not generate a run-time check on the built object if tag
219
      --  checks are suppressed for the result type or VM_Target /= No_VM
220
 
221
      if Tag_Checks_Suppressed (Etype (Result_Typ))
222
        or else not Tagged_Type_Expansion
223
      then
224
         null;
225
 
226
      --  Generate a class-wide membership test to ensure that the call's tag
227
      --  argument denotes a type within the class. We must keep separate the
228
      --  case in which the Result_Type of the constructor function is a tagged
229
      --  type from the case in which it is an abstract interface because the
230
      --  run-time subprogram required to check these cases differ (and have
231
      --  one difference in their parameters profile).
232
 
233
      --  Call CW_Membership if the Result_Type is a tagged type to look for
234
      --  the tag in the table of ancestor tags.
235
 
236
      elsif not Is_Interface (Result_Typ) then
237
         declare
238
            Obj_Tag_Node : Node_Id := Duplicate_Subexpr (Tag_Arg);
239
            CW_Test_Node : Node_Id;
240
 
241
         begin
242
            Build_CW_Membership (Loc,
243
              Obj_Tag_Node => Obj_Tag_Node,
244
              Typ_Tag_Node =>
245
                New_Reference_To (
246
                   Node (First_Elmt (Access_Disp_Table (
247
                                       Root_Type (Result_Typ)))), Loc),
248
              Related_Nod => N,
249
              New_Node    => CW_Test_Node);
250
 
251
            Insert_Action (N,
252
              Make_Implicit_If_Statement (N,
253
                Condition =>
254
                  Make_Op_Not (Loc, CW_Test_Node),
255
                Then_Statements =>
256
                  New_List (Make_Raise_Statement (Loc,
257
                              New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
258
         end;
259
 
260
      --  Call IW_Membership test if the Result_Type is an abstract interface
261
      --  to look for the tag in the table of interface tags.
262
 
263
      else
264
         Insert_Action (N,
265
           Make_Implicit_If_Statement (N,
266
             Condition =>
267
               Make_Op_Not (Loc,
268
                 Make_Function_Call (Loc,
269
                    Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc),
270
                    Parameter_Associations => New_List (
271
                      Make_Attribute_Reference (Loc,
272
                        Prefix         => Duplicate_Subexpr (Tag_Arg),
273
                        Attribute_Name => Name_Address),
274
 
275
                      New_Reference_To (
276
                        Node (First_Elmt (Access_Disp_Table (
277
                                            Root_Type (Result_Typ)))), Loc)))),
278
             Then_Statements =>
279
               New_List (
280
                 Make_Raise_Statement (Loc,
281
                   Name => New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
282
      end if;
283
   end Expand_Dispatching_Constructor_Call;
284
 
285
   ---------------------------
286
   -- Expand_Exception_Call --
287
   ---------------------------
288
 
289
   --  If the function call is not within an exception handler, then the call
290
   --  is replaced by a null string. Otherwise the appropriate routine in
291
   --  Ada.Exceptions is called passing the choice parameter specification
292
   --  from the enclosing handler. If the enclosing handler lacks a choice
293
   --  parameter, then one is supplied.
294
 
295
   procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id) is
296
      Loc : constant Source_Ptr := Sloc (N);
297
      P   : Node_Id;
298
      E   : Entity_Id;
299
 
300
   begin
301
      --  Climb up parents to see if we are in exception handler
302
 
303
      P := Parent (N);
304
      loop
305
         --  Case of not in exception handler, replace by null string
306
 
307
         if No (P) then
308
            Rewrite (N,
309
              Make_String_Literal (Loc,
310
                Strval => ""));
311
            exit;
312
 
313
         --  Case of in exception handler
314
 
315
         elsif Nkind (P) = N_Exception_Handler then
316
 
317
            --  Handler cannot be used for a local raise, and furthermore, this
318
            --  is a violation of the No_Exception_Propagation restriction.
319
 
320
            Set_Local_Raise_Not_OK (P);
321
            Check_Restriction (No_Exception_Propagation, N);
322
 
323
            --  If no choice parameter present, then put one there. Note that
324
            --  we do not need to put it on the entity chain, since no one will
325
            --  be referencing it by normal visibility methods.
326
 
327
            if No (Choice_Parameter (P)) then
328
               E := Make_Defining_Identifier (Loc, New_Internal_Name ('E'));
329
               Set_Choice_Parameter (P, E);
330
               Set_Ekind (E, E_Variable);
331
               Set_Etype (E, RTE (RE_Exception_Occurrence));
332
               Set_Scope (E, Current_Scope);
333
            end if;
334
 
335
            Rewrite (N,
336
              Make_Function_Call (Loc,
337
                Name => New_Occurrence_Of (RTE (Ent), Loc),
338
                Parameter_Associations => New_List (
339
                  New_Occurrence_Of (Choice_Parameter (P), Loc))));
340
            exit;
341
 
342
         --  Keep climbing!
343
 
344
         else
345
            P := Parent (P);
346
         end if;
347
      end loop;
348
 
349
      Analyze_And_Resolve (N, Standard_String);
350
   end Expand_Exception_Call;
351
 
352
   ------------------------
353
   -- Expand_Import_Call --
354
   ------------------------
355
 
356
   --  The function call must have a static string as its argument. We create
357
   --  a dummy variable which uses this string as the external name in an
358
   --  Import pragma. The result is then obtained as the address of this
359
   --  dummy variable, converted to the appropriate target type.
360
 
361
   procedure Expand_Import_Call (N : Node_Id) is
362
      Loc : constant Source_Ptr := Sloc (N);
363
      Ent : constant Entity_Id  := Entity (Name (N));
364
      Str : constant Node_Id    := First_Actual (N);
365
      Dum : Entity_Id;
366
 
367
   begin
368
      Dum := Make_Defining_Identifier (Loc, New_Internal_Name ('D'));
369
 
370
      Insert_Actions (N, New_List (
371
        Make_Object_Declaration (Loc,
372
          Defining_Identifier => Dum,
373
          Object_Definition   =>
374
            New_Occurrence_Of (Standard_Character, Loc)),
375
 
376
        Make_Pragma (Loc,
377
          Chars => Name_Import,
378
          Pragma_Argument_Associations => New_List (
379
            Make_Pragma_Argument_Association (Loc,
380
              Expression => Make_Identifier (Loc, Name_Ada)),
381
 
382
            Make_Pragma_Argument_Association (Loc,
383
              Expression => Make_Identifier (Loc, Chars (Dum))),
384
 
385
            Make_Pragma_Argument_Association (Loc,
386
              Chars => Name_Link_Name,
387
              Expression => Relocate_Node (Str))))));
388
 
389
      Rewrite (N,
390
        Unchecked_Convert_To (Etype (Ent),
391
          Make_Attribute_Reference (Loc,
392
            Prefix         => Make_Identifier (Loc, Chars (Dum)),
393
            Attribute_Name => Name_Address)));
394
 
395
      Analyze_And_Resolve (N, Etype (Ent));
396
   end Expand_Import_Call;
397
 
398
   ---------------------------
399
   -- Expand_Intrinsic_Call --
400
   ---------------------------
401
 
402
   procedure Expand_Intrinsic_Call (N : Node_Id; E : Entity_Id) is
403
      Nam : Name_Id;
404
 
405
   begin
406
      --  If an external name is specified for the intrinsic, it is handled
407
      --  by the back-end: leave the call node unchanged for now.
408
 
409
      if Present (Interface_Name (E)) then
410
         return;
411
      end if;
412
 
413
      --  If the intrinsic subprogram is generic, gets its original name
414
 
415
      if Present (Parent (E))
416
        and then Present (Generic_Parent (Parent (E)))
417
      then
418
         Nam := Chars (Generic_Parent (Parent (E)));
419
      else
420
         Nam := Chars (E);
421
      end if;
422
 
423
      if Nam = Name_Asm then
424
         Expand_Asm_Call (N);
425
 
426
      elsif Nam = Name_Divide then
427
         Expand_Decimal_Divide_Call (N);
428
 
429
      elsif Nam = Name_Exception_Information then
430
         Expand_Exception_Call (N, RE_Exception_Information);
431
 
432
      elsif Nam = Name_Exception_Message then
433
         Expand_Exception_Call (N, RE_Exception_Message);
434
 
435
      elsif Nam = Name_Exception_Name then
436
         Expand_Exception_Call (N, RE_Exception_Name_Simple);
437
 
438
      elsif Nam = Name_Generic_Dispatching_Constructor then
439
         Expand_Dispatching_Constructor_Call (N);
440
 
441
      elsif Nam = Name_Import_Address
442
              or else
443
            Nam = Name_Import_Largest_Value
444
              or else
445
            Nam = Name_Import_Value
446
      then
447
         Expand_Import_Call (N);
448
 
449
      elsif Nam = Name_Is_Negative then
450
         Expand_Is_Negative (N);
451
 
452
      elsif Nam = Name_Rotate_Left then
453
         Expand_Shift (N, E, N_Op_Rotate_Left);
454
 
455
      elsif Nam = Name_Rotate_Right then
456
         Expand_Shift (N, E, N_Op_Rotate_Right);
457
 
458
      elsif Nam = Name_Shift_Left then
459
         Expand_Shift (N, E, N_Op_Shift_Left);
460
 
461
      elsif Nam = Name_Shift_Right then
462
         Expand_Shift (N, E, N_Op_Shift_Right);
463
 
464
      elsif Nam = Name_Shift_Right_Arithmetic then
465
         Expand_Shift (N, E, N_Op_Shift_Right_Arithmetic);
466
 
467
      elsif Nam = Name_Unchecked_Conversion then
468
         Expand_Unc_Conversion (N, E);
469
 
470
      elsif Nam = Name_Unchecked_Deallocation then
471
         Expand_Unc_Deallocation (N);
472
 
473
      elsif Nam = Name_To_Address then
474
         Expand_To_Address (N);
475
 
476
      elsif Nam = Name_To_Pointer then
477
         Expand_To_Pointer (N);
478
 
479
      elsif Nam = Name_File
480
        or else Nam = Name_Line
481
        or else Nam = Name_Source_Location
482
        or else Nam = Name_Enclosing_Entity
483
      then
484
         Expand_Source_Info (N, Nam);
485
 
486
         --  If we have a renaming, expand the call to the original operation,
487
         --  which must itself be intrinsic, since renaming requires matching
488
         --  conventions and this has already been checked.
489
 
490
      elsif Present (Alias (E)) then
491
         Expand_Intrinsic_Call (N,  Alias (E));
492
 
493
         --  The only other case is where an external name was specified,
494
         --  since this is the only way that an otherwise unrecognized
495
         --  name could escape the checking in Sem_Prag. Nothing needs
496
         --  to be done in such a case, since we pass such a call to the
497
         --  back end unchanged.
498
 
499
      else
500
         null;
501
      end if;
502
   end Expand_Intrinsic_Call;
503
 
504
   ------------------------
505
   -- Expand_Is_Negative --
506
   ------------------------
507
 
508
   procedure Expand_Is_Negative (N : Node_Id) is
509
      Loc   : constant Source_Ptr := Sloc (N);
510
      Opnd  : constant Node_Id    := Relocate_Node (First_Actual (N));
511
 
512
   begin
513
 
514
      --  We replace the function call by the following expression
515
 
516
      --    if Opnd < 0.0 then
517
      --       True
518
      --    else
519
      --       if Opnd > 0.0 then
520
      --          False;
521
      --       else
522
      --          Float_Unsigned!(Float (Opnd)) /= 0
523
      --       end if;
524
      --    end if;
525
 
526
      Rewrite (N,
527
        Make_Conditional_Expression (Loc,
528
          Expressions => New_List (
529
            Make_Op_Lt (Loc,
530
              Left_Opnd  => Duplicate_Subexpr (Opnd),
531
              Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
532
 
533
            New_Occurrence_Of (Standard_True, Loc),
534
 
535
            Make_Conditional_Expression (Loc,
536
             Expressions => New_List (
537
               Make_Op_Gt (Loc,
538
                 Left_Opnd  => Duplicate_Subexpr_No_Checks (Opnd),
539
                 Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
540
 
541
               New_Occurrence_Of (Standard_False, Loc),
542
 
543
                Make_Op_Ne (Loc,
544
                  Left_Opnd =>
545
                    Unchecked_Convert_To
546
                      (RTE (RE_Float_Unsigned),
547
                       Convert_To
548
                         (Standard_Float,
549
                          Duplicate_Subexpr_No_Checks (Opnd))),
550
                  Right_Opnd =>
551
                    Make_Integer_Literal (Loc, 0)))))));
552
 
553
      Analyze_And_Resolve (N, Standard_Boolean);
554
   end Expand_Is_Negative;
555
 
556
   ------------------
557
   -- Expand_Shift --
558
   ------------------
559
 
560
   --  This procedure is used to convert a call to a shift function to the
561
   --  corresponding operator node. This conversion is not done by the usual
562
   --  circuit for converting calls to operator functions (e.g. "+"(1,2)) to
563
   --  operator nodes, because shifts are not predefined operators.
564
 
565
   --  As a result, whenever a shift is used in the source program, it will
566
   --  remain as a call until converted by this routine to the operator node
567
   --  form which Gigi is expecting to see.
568
 
569
   --  Note: it is possible for the expander to generate shift operator nodes
570
   --  directly, which will be analyzed in the normal manner by calling Analyze
571
   --  and Resolve. Such shift operator nodes will not be seen by Expand_Shift.
572
 
573
   procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind) is
574
      Loc   : constant Source_Ptr := Sloc (N);
575
      Typ   : constant Entity_Id  := Etype (N);
576
      Left  : constant Node_Id    := First_Actual (N);
577
      Right : constant Node_Id    := Next_Actual (Left);
578
      Ltyp  : constant Node_Id    := Etype (Left);
579
      Rtyp  : constant Node_Id    := Etype (Right);
580
      Snode : Node_Id;
581
 
582
   begin
583
      Snode := New_Node (K, Loc);
584
      Set_Left_Opnd  (Snode, Relocate_Node (Left));
585
      Set_Right_Opnd (Snode, Relocate_Node (Right));
586
      Set_Chars      (Snode, Chars (E));
587
      Set_Etype      (Snode, Base_Type (Typ));
588
      Set_Entity     (Snode, E);
589
 
590
      if Compile_Time_Known_Value (Type_High_Bound (Rtyp))
591
        and then Expr_Value (Type_High_Bound (Rtyp)) < Esize (Ltyp)
592
      then
593
         Set_Shift_Count_OK (Snode, True);
594
      end if;
595
 
596
      --  Do the rewrite. Note that we don't call Analyze and Resolve on
597
      --  this node, because it already got analyzed and resolved when
598
      --  it was a function call!
599
 
600
      Rewrite (N, Snode);
601
      Set_Analyzed (N);
602
   end Expand_Shift;
603
 
604
   ------------------------
605
   -- Expand_Source_Info --
606
   ------------------------
607
 
608
   procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id) is
609
      Loc : constant Source_Ptr := Sloc (N);
610
      Ent : Entity_Id;
611
 
612
      procedure Write_Entity_Name (E : Entity_Id);
613
      --  Recursive procedure to construct string for qualified name of
614
      --  enclosing program unit. The qualification stops at an enclosing
615
      --  scope has no source name (block or loop). If entity is a subprogram
616
      --  instance, skip enclosing wrapper package.
617
 
618
      -----------------------
619
      -- Write_Entity_Name --
620
      -----------------------
621
 
622
      procedure Write_Entity_Name (E : Entity_Id) is
623
         SDef : Source_Ptr;
624
         TDef : constant Source_Buffer_Ptr :=
625
                  Source_Text (Get_Source_File_Index (Sloc (E)));
626
 
627
      begin
628
         --  Nothing to do if at outer level
629
 
630
         if Scope (E) = Standard_Standard then
631
            null;
632
 
633
         --  If scope comes from source, write its name
634
 
635
         elsif Comes_From_Source (Scope (E)) then
636
            Write_Entity_Name (Scope (E));
637
            Add_Char_To_Name_Buffer ('.');
638
 
639
         --  If in wrapper package skip past it
640
 
641
         elsif Is_Wrapper_Package (Scope (E)) then
642
            Write_Entity_Name (Scope (Scope (E)));
643
            Add_Char_To_Name_Buffer ('.');
644
 
645
         --  Otherwise nothing to output (happens in unnamed block statements)
646
 
647
         else
648
            null;
649
         end if;
650
 
651
         --  Loop to output the name
652
 
653
         --  is this right wrt wide char encodings ??? (no!)
654
 
655
         SDef := Sloc (E);
656
         while TDef (SDef) in '0' .. '9'
657
           or else TDef (SDef) >= 'A'
658
           or else TDef (SDef) = ASCII.ESC
659
         loop
660
            Add_Char_To_Name_Buffer (TDef (SDef));
661
            SDef := SDef + 1;
662
         end loop;
663
      end Write_Entity_Name;
664
 
665
   --  Start of processing for Expand_Source_Info
666
 
667
   begin
668
      --  Integer cases
669
 
670
      if Nam = Name_Line then
671
         Rewrite (N,
672
           Make_Integer_Literal (Loc,
673
             Intval => UI_From_Int (Int (Get_Logical_Line_Number (Loc)))));
674
         Analyze_And_Resolve (N, Standard_Positive);
675
 
676
      --  String cases
677
 
678
      else
679
         Name_Len := 0;
680
 
681
         case Nam is
682
            when Name_File =>
683
               Get_Decoded_Name_String
684
                 (Reference_Name (Get_Source_File_Index (Loc)));
685
 
686
            when Name_Source_Location =>
687
               Build_Location_String (Loc);
688
 
689
            when Name_Enclosing_Entity =>
690
 
691
               --  Skip enclosing blocks to reach enclosing unit
692
 
693
               Ent := Current_Scope;
694
               while Present (Ent) loop
695
                  exit when Ekind (Ent) /= E_Block
696
                    and then Ekind (Ent) /= E_Loop;
697
                  Ent := Scope (Ent);
698
               end loop;
699
 
700
               --  Ent now points to the relevant defining entity
701
 
702
               Write_Entity_Name (Ent);
703
 
704
            when others =>
705
               raise Program_Error;
706
         end case;
707
 
708
         Rewrite (N,
709
           Make_String_Literal (Loc,
710
             Strval => String_From_Name_Buffer));
711
         Analyze_And_Resolve (N, Standard_String);
712
      end if;
713
 
714
      Set_Is_Static_Expression (N);
715
   end Expand_Source_Info;
716
 
717
   ---------------------------
718
   -- Expand_Unc_Conversion --
719
   ---------------------------
720
 
721
   procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id) is
722
      Func : constant Entity_Id  := Entity (Name (N));
723
      Conv : Node_Id;
724
      Ftyp : Entity_Id;
725
      Ttyp : Entity_Id;
726
 
727
   begin
728
      --  Rewrite as unchecked conversion node. Note that we must convert
729
      --  the operand to the formal type of the input parameter of the
730
      --  function, so that the resulting N_Unchecked_Type_Conversion
731
      --  call indicates the correct types for Gigi.
732
 
733
      --  Right now, we only do this if a scalar type is involved. It is
734
      --  not clear if it is needed in other cases. If we do attempt to
735
      --  do the conversion unconditionally, it crashes 3411-018. To be
736
      --  investigated further ???
737
 
738
      Conv := Relocate_Node (First_Actual (N));
739
      Ftyp := Etype (First_Formal (Func));
740
 
741
      if Is_Scalar_Type (Ftyp) then
742
         Conv := Convert_To (Ftyp, Conv);
743
         Set_Parent (Conv, N);
744
         Analyze_And_Resolve (Conv);
745
      end if;
746
 
747
      --  The instantiation of Unchecked_Conversion creates a wrapper package,
748
      --  and the target type is declared as a subtype of the actual. Recover
749
      --  the actual, which is the subtype indic. in the subtype declaration
750
      --  for the target type. This is semantically correct, and avoids
751
      --  anomalies with access subtypes. For entities, leave type as is.
752
 
753
      --  We do the analysis here, because we do not want the compiler
754
      --  to try to optimize or otherwise reorganize the unchecked
755
      --  conversion node.
756
 
757
      Ttyp := Etype (E);
758
 
759
      if Is_Entity_Name (Conv) then
760
         null;
761
 
762
      elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then
763
         Ttyp := Entity (Subtype_Indication (Parent (Etype (E))));
764
 
765
      elsif Is_Itype (Ttyp) then
766
         Ttyp :=
767
           Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp)));
768
      else
769
         raise Program_Error;
770
      end if;
771
 
772
      Rewrite (N, Unchecked_Convert_To (Ttyp, Conv));
773
      Set_Etype (N, Ttyp);
774
      Set_Analyzed (N);
775
 
776
      if Nkind (N) = N_Unchecked_Type_Conversion then
777
         Expand_N_Unchecked_Type_Conversion (N);
778
      end if;
779
   end Expand_Unc_Conversion;
780
 
781
   -----------------------------
782
   -- Expand_Unc_Deallocation --
783
   -----------------------------
784
 
785
   --  Generate the following Code :
786
 
787
   --    if Arg /= null then
788
   --     <Finalize_Call> (.., T'Class(Arg.all), ..);  -- for controlled types
789
   --       Free (Arg);
790
   --       Arg := Null;
791
   --    end if;
792
 
793
   --  For a task, we also generate a call to Free_Task to ensure that the
794
   --  task itself is freed if it is terminated, ditto for a simple protected
795
   --  object, with a call to Finalize_Protection. For composite types that
796
   --  have tasks or simple protected objects as components, we traverse the
797
   --  structures to find and terminate those components.
798
 
799
   procedure Expand_Unc_Deallocation (N : Node_Id) is
800
      Loc   : constant Source_Ptr := Sloc (N);
801
      Arg   : constant Node_Id    := First_Actual (N);
802
      Typ   : constant Entity_Id  := Etype (Arg);
803
      Stmts : constant List_Id    := New_List;
804
      Rtyp  : constant Entity_Id  := Underlying_Type (Root_Type (Typ));
805
      Pool  : constant Entity_Id  := Associated_Storage_Pool (Rtyp);
806
 
807
      Desig_T   : constant Entity_Id  := Designated_Type (Typ);
808
      Gen_Code  : Node_Id;
809
      Free_Node : Node_Id;
810
      Deref     : Node_Id;
811
      Free_Arg  : Node_Id;
812
      Free_Cod  : List_Id;
813
      Blk       : Node_Id;
814
 
815
      Arg_Known_Non_Null : constant Boolean := Known_Non_Null (N);
816
      --  This captures whether we know the argument to be non-null so that
817
      --  we can avoid the test. The reason that we need to capture this is
818
      --  that we analyze some generated statements before properly attaching
819
      --  them to the tree, and that can disturb current value settings.
820
 
821
   begin
822
      if No_Pool_Assigned (Rtyp) then
823
         Error_Msg_N ("?deallocation from empty storage pool!", N);
824
      end if;
825
 
826
      --  Nothing to do if we know the argument is null
827
 
828
      if Known_Null (N) then
829
         return;
830
      end if;
831
 
832
      --  Processing for pointer to controlled type
833
 
834
      if Needs_Finalization (Desig_T) then
835
         Deref :=
836
           Make_Explicit_Dereference (Loc,
837
             Prefix => Duplicate_Subexpr_No_Checks (Arg));
838
 
839
         --  If the type is tagged, then we must force dispatching on the
840
         --  finalization call because the designated type may not be the
841
         --  actual type of the object.
842
 
843
         if Is_Tagged_Type (Desig_T)
844
           and then not Is_Class_Wide_Type (Desig_T)
845
         then
846
            Deref := Unchecked_Convert_To (Class_Wide_Type (Desig_T), Deref);
847
 
848
         elsif not Is_Tagged_Type (Desig_T) then
849
 
850
            --  Set type of result, to force a conversion when needed (see
851
            --  exp_ch7, Convert_View), given that Deep_Finalize may be
852
            --  inherited from the parent type, and we need the type of the
853
            --  expression to see whether the conversion is in fact needed.
854
 
855
            Set_Etype (Deref, Desig_T);
856
         end if;
857
 
858
         Free_Cod :=
859
           Make_Final_Call
860
            (Ref         => Deref,
861
             Typ         => Desig_T,
862
             With_Detach => New_Reference_To (Standard_True, Loc));
863
 
864
         if Abort_Allowed then
865
            Prepend_To (Free_Cod,
866
              Build_Runtime_Call (Loc, RE_Abort_Defer));
867
 
868
            Blk :=
869
              Make_Block_Statement (Loc, Handled_Statement_Sequence =>
870
                Make_Handled_Sequence_Of_Statements (Loc,
871
                  Statements  => Free_Cod,
872
                  At_End_Proc =>
873
                    New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc)));
874
 
875
            --  We now expand the exception (at end) handler. We set a
876
            --  temporary parent pointer since we have not attached Blk
877
            --  to the tree yet.
878
 
879
            Set_Parent (Blk, N);
880
            Analyze (Blk);
881
            Expand_At_End_Handler
882
              (Handled_Statement_Sequence (Blk), Entity (Identifier (Blk)));
883
            Append (Blk, Stmts);
884
 
885
            --  We kill saved current values, since analyzing statements not
886
            --  properly attached to the tree can set wrong current values.
887
 
888
            Kill_Current_Values;
889
 
890
         else
891
            Append_List_To (Stmts, Free_Cod);
892
         end if;
893
      end if;
894
 
895
      --  For a task type, call Free_Task before freeing the ATCB
896
 
897
      if Is_Task_Type (Desig_T) then
898
         declare
899
            Stat : Node_Id := Prev (N);
900
            Nam1 : Node_Id;
901
            Nam2 : Node_Id;
902
 
903
         begin
904
            --  An Abort followed by a Free will not do what the user
905
            --  expects, because the abort is not immediate. This is
906
            --  worth a friendly warning.
907
 
908
            while Present (Stat)
909
              and then not Comes_From_Source (Original_Node (Stat))
910
            loop
911
               Prev (Stat);
912
            end loop;
913
 
914
            if Present (Stat)
915
              and then Nkind (Original_Node (Stat)) = N_Abort_Statement
916
            then
917
               Stat := Original_Node (Stat);
918
               Nam1 := First (Names (Stat));
919
               Nam2 := Original_Node (First (Parameter_Associations (N)));
920
 
921
               if Nkind (Nam1) = N_Explicit_Dereference
922
                 and then Is_Entity_Name (Prefix (Nam1))
923
                 and then Is_Entity_Name (Nam2)
924
                 and then Entity (Prefix (Nam1)) = Entity (Nam2)
925
               then
926
                  Error_Msg_N ("abort may take time to complete?", N);
927
                  Error_Msg_N ("\deallocation might have no effect?", N);
928
                  Error_Msg_N ("\safer to wait for termination.?", N);
929
               end if;
930
            end if;
931
         end;
932
 
933
         Append_To
934
           (Stmts, Cleanup_Task (N, Duplicate_Subexpr_No_Checks (Arg)));
935
 
936
      --  For composite types that contain tasks, recurse over the structure
937
      --  to build the selectors for the task subcomponents.
938
 
939
      elsif Has_Task (Desig_T) then
940
         if Is_Record_Type (Desig_T) then
941
            Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
942
 
943
         elsif Is_Array_Type (Desig_T) then
944
            Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
945
         end if;
946
      end if;
947
 
948
      --  Same for simple protected types. Eventually call Finalize_Protection
949
      --  before freeing the PO for each protected component.
950
 
951
      if Is_Simple_Protected_Type (Desig_T) then
952
         Append_To (Stmts,
953
           Cleanup_Protected_Object (N, Duplicate_Subexpr_No_Checks (Arg)));
954
 
955
      elsif Has_Simple_Protected_Object (Desig_T) then
956
         if Is_Record_Type (Desig_T) then
957
            Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
958
         elsif Is_Array_Type (Desig_T) then
959
            Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
960
         end if;
961
      end if;
962
 
963
      --  Normal processing for non-controlled types
964
 
965
      Free_Arg := Duplicate_Subexpr_No_Checks (Arg);
966
      Free_Node := Make_Free_Statement (Loc, Empty);
967
      Append_To (Stmts, Free_Node);
968
      Set_Storage_Pool (Free_Node, Pool);
969
 
970
      --  Deal with storage pool
971
 
972
      if Present (Pool) then
973
 
974
         --  Freeing the secondary stack is meaningless
975
 
976
         if Is_RTE (Pool, RE_SS_Pool) then
977
            null;
978
 
979
         elsif Is_Class_Wide_Type (Etype (Pool)) then
980
 
981
            --  Case of a class-wide pool type: make a dispatching call
982
            --  to Deallocate through the class-wide Deallocate_Any.
983
 
984
            Set_Procedure_To_Call (Free_Node,
985
              RTE (RE_Deallocate_Any));
986
 
987
         else
988
            --  Case of a specific pool type: make a statically bound call
989
 
990
            Set_Procedure_To_Call (Free_Node,
991
              Find_Prim_Op (Etype (Pool), Name_Deallocate));
992
         end if;
993
      end if;
994
 
995
      if Present (Procedure_To_Call (Free_Node)) then
996
 
997
         --  For all cases of a Deallocate call, the back-end needs to be
998
         --  able to compute the size of the object being freed. This may
999
         --  require some adjustments for objects of dynamic size.
1000
         --
1001
         --  If the type is class wide, we generate an implicit type with the
1002
         --  right dynamic size, so that the deallocate call gets the right
1003
         --  size parameter computed by GIGI. Same for an access to
1004
         --  unconstrained packed array.
1005
 
1006
         if Is_Class_Wide_Type (Desig_T)
1007
           or else
1008
            (Is_Array_Type (Desig_T)
1009
               and then not Is_Constrained (Desig_T)
1010
               and then Is_Packed (Desig_T))
1011
         then
1012
            declare
1013
               Deref    : constant Node_Id :=
1014
                            Make_Explicit_Dereference (Loc,
1015
                              Duplicate_Subexpr_No_Checks (Arg));
1016
               D_Subtyp : Node_Id;
1017
               D_Type   : Entity_Id;
1018
 
1019
            begin
1020
               Set_Etype  (Deref, Typ);
1021
               Set_Parent (Deref, Free_Node);
1022
               D_Subtyp := Make_Subtype_From_Expr (Deref, Desig_T);
1023
 
1024
               if Nkind (D_Subtyp) in N_Has_Entity then
1025
                  D_Type := Entity (D_Subtyp);
1026
 
1027
               else
1028
                  D_Type := Make_Defining_Identifier (Loc,
1029
                              New_Internal_Name ('A'));
1030
                  Insert_Action (Deref,
1031
                    Make_Subtype_Declaration (Loc,
1032
                      Defining_Identifier => D_Type,
1033
                      Subtype_Indication  => D_Subtyp));
1034
 
1035
               end if;
1036
 
1037
               --  Force freezing at the point of the dereference. For the
1038
               --  class wide case, this avoids having the subtype frozen
1039
               --  before the equivalent type.
1040
 
1041
               Freeze_Itype (D_Type, Deref);
1042
 
1043
               Set_Actual_Designated_Subtype (Free_Node, D_Type);
1044
            end;
1045
 
1046
         end if;
1047
      end if;
1048
 
1049
      --  Ada 2005 (AI-251): In case of abstract interface type we must
1050
      --  displace the pointer to reference the base of the object to
1051
      --  deallocate its memory, unless we're targetting a VM, in which case
1052
      --  no special processing is required.
1053
 
1054
      --  Generate:
1055
      --    free (Base_Address (Obj_Ptr))
1056
 
1057
      if Is_Interface (Directly_Designated_Type (Typ))
1058
        and then Tagged_Type_Expansion
1059
      then
1060
         Set_Expression (Free_Node,
1061
           Unchecked_Convert_To (Typ,
1062
             Make_Function_Call (Loc,
1063
               Name => New_Reference_To (RTE (RE_Base_Address), Loc),
1064
               Parameter_Associations => New_List (
1065
                 Unchecked_Convert_To (RTE (RE_Address), Free_Arg)))));
1066
 
1067
      --  Generate:
1068
      --    free (Obj_Ptr)
1069
 
1070
      else
1071
         Set_Expression (Free_Node, Free_Arg);
1072
      end if;
1073
 
1074
      --  Only remaining step is to set result to null, or generate a
1075
      --  raise of constraint error if the target object is "not null".
1076
 
1077
      if Can_Never_Be_Null (Etype (Arg)) then
1078
         Append_To (Stmts,
1079
           Make_Raise_Constraint_Error (Loc,
1080
             Reason => CE_Access_Check_Failed));
1081
 
1082
      else
1083
         declare
1084
            Lhs : constant Node_Id := Duplicate_Subexpr_No_Checks (Arg);
1085
         begin
1086
            Set_Assignment_OK (Lhs);
1087
            Append_To (Stmts,
1088
              Make_Assignment_Statement (Loc,
1089
                Name       => Lhs,
1090
                Expression => Make_Null (Loc)));
1091
         end;
1092
      end if;
1093
 
1094
      --  If we know the argument is non-null, then make a block statement
1095
      --  that contains the required statements, no need for a test.
1096
 
1097
      if Arg_Known_Non_Null then
1098
         Gen_Code :=
1099
           Make_Block_Statement (Loc,
1100
             Handled_Statement_Sequence =>
1101
               Make_Handled_Sequence_Of_Statements (Loc,
1102
             Statements => Stmts));
1103
 
1104
      --  If the argument may be null, wrap the statements inside an IF that
1105
      --  does an explicit test to exclude the null case.
1106
 
1107
      else
1108
         Gen_Code :=
1109
           Make_Implicit_If_Statement (N,
1110
             Condition =>
1111
               Make_Op_Ne (Loc,
1112
                 Left_Opnd  => Duplicate_Subexpr (Arg),
1113
                 Right_Opnd => Make_Null (Loc)),
1114
             Then_Statements => Stmts);
1115
      end if;
1116
 
1117
      --  Rewrite the call
1118
 
1119
      Rewrite (N, Gen_Code);
1120
      Analyze (N);
1121
   end Expand_Unc_Deallocation;
1122
 
1123
   -----------------------
1124
   -- Expand_To_Address --
1125
   -----------------------
1126
 
1127
   procedure Expand_To_Address (N : Node_Id) is
1128
      Loc : constant Source_Ptr := Sloc (N);
1129
      Arg : constant Node_Id := First_Actual (N);
1130
      Obj : Node_Id;
1131
 
1132
   begin
1133
      Remove_Side_Effects (Arg);
1134
 
1135
      Obj := Make_Explicit_Dereference (Loc, Relocate_Node (Arg));
1136
 
1137
      Rewrite (N,
1138
        Make_Conditional_Expression (Loc,
1139
          Expressions => New_List (
1140
            Make_Op_Eq (Loc,
1141
              Left_Opnd => New_Copy_Tree (Arg),
1142
              Right_Opnd => Make_Null (Loc)),
1143
            New_Occurrence_Of (RTE (RE_Null_Address), Loc),
1144
            Make_Attribute_Reference (Loc,
1145
              Prefix         => Obj,
1146
              Attribute_Name => Name_Address))));
1147
 
1148
      Analyze_And_Resolve (N, RTE (RE_Address));
1149
   end Expand_To_Address;
1150
 
1151
   -----------------------
1152
   -- Expand_To_Pointer --
1153
   -----------------------
1154
 
1155
   procedure Expand_To_Pointer (N : Node_Id) is
1156
      Arg : constant Node_Id := First_Actual (N);
1157
 
1158
   begin
1159
      Rewrite (N, Unchecked_Convert_To (Etype (N), Arg));
1160
      Analyze (N);
1161
   end Expand_To_Pointer;
1162
 
1163
end Exp_Intr;

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