summaryrefslogtreecommitdiff
path: root/gcc/ada/sem_elim.adb
blob: f1461237adcd022da6d0a629e307c13c43a1ece0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             S E M _ E L I M                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1997-2007, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Atree;    use Atree;
with Einfo;    use Einfo;
with Errout;   use Errout;
with Namet;    use Namet;
with Nlists;   use Nlists;
with Sem_Prag; use Sem_Prag;
with Sinput;   use Sinput;
with Sinfo;    use Sinfo;
with Snames;   use Snames;
with Stand;    use Stand;
with Stringt;  use Stringt;
with Table;

with GNAT.HTable; use GNAT.HTable;

package body Sem_Elim is

   No_Elimination : Boolean;
   --  Set True if no Eliminate pragmas active

   ---------------------
   -- Data Structures --
   ---------------------

   --  A single pragma Eliminate is represented by the following record

   type Elim_Data;
   type Access_Elim_Data is access Elim_Data;

   type Names is array (Nat range <>) of Name_Id;
   --  Type used to represent set of names. Used for names in Unit_Name
   --  and also the set of names in Argument_Types.

   type Access_Names is access Names;

   type Elim_Data is record

      Unit_Name : Access_Names;
      --  Unit name, broken down into a set of names (e.g. A.B.C is
      --  represented as Name_Id values for A, B, C in sequence).

      Entity_Name : Name_Id;
      --  Entity name if Entity parameter if present. If no Entity parameter
      --  was supplied, then Entity_Node is set to Empty, and the Entity_Name
      --  field contains the last identifier name in the Unit_Name.

      Entity_Scope : Access_Names;
      --  Static scope of the entity within the compilation unit represented by
      --  Unit_Name.

      Entity_Node : Node_Id;
      --  Save node of entity argument, for posting error messages. Set
      --  to Empty if there is no entity argument.

      Parameter_Types : Access_Names;
      --  Set to set of names given for parameter types. If no parameter
      --  types argument is present, this argument is set to null.

      Result_Type : Name_Id;
      --  Result type name if Result_Types parameter present, No_Name if not

      Source_Location : Name_Id;
      --  String describing the source location of subprogram defining name if
      --  Source_Location parameter present, No_Name if not

      Hash_Link : Access_Elim_Data;
      --  Link for hash table use

      Homonym : Access_Elim_Data;
      --  Pointer to next entry with same key

      Prag : Node_Id;
      --  Node_Id for Eliminate pragma

   end record;

   ----------------
   -- Hash_Table --
   ----------------

   --  Setup hash table using the Entity_Name field as the hash key

   subtype Element is Elim_Data;
   subtype Elmt_Ptr is Access_Elim_Data;

   subtype Key is Name_Id;

   type Header_Num is range 0 .. 1023;

   Null_Ptr : constant Elmt_Ptr := null;

   ----------------------
   -- Hash_Subprograms --
   ----------------------

   package Hash_Subprograms is

      function Equal (F1, F2 : Key) return Boolean;
      pragma Inline (Equal);

      function Get_Key (E : Elmt_Ptr) return Key;
      pragma Inline (Get_Key);

      function Hash (F : Key) return Header_Num;
      pragma Inline (Hash);

      function Next (E : Elmt_Ptr) return Elmt_Ptr;
      pragma Inline (Next);

      procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
      pragma Inline (Set_Next);

   end Hash_Subprograms;

   package body Hash_Subprograms is

      -----------
      -- Equal --
      -----------

      function Equal (F1, F2 : Key) return Boolean is
      begin
         return F1 = F2;
      end Equal;

      -------------
      -- Get_Key --
      -------------

      function Get_Key (E : Elmt_Ptr) return Key is
      begin
         return E.Entity_Name;
      end Get_Key;

      ----------
      -- Hash --
      ----------

      function Hash (F : Key) return Header_Num is
      begin
         return Header_Num (Int (F) mod 1024);
      end Hash;

      ----------
      -- Next --
      ----------

      function Next (E : Elmt_Ptr) return Elmt_Ptr is
      begin
         return E.Hash_Link;
      end Next;

      --------------
      -- Set_Next --
      --------------

      procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
      begin
         E.Hash_Link := Next;
      end Set_Next;
   end Hash_Subprograms;

   ------------
   -- Tables --
   ------------

   --  The following table records the data for each pragmas, using the
   --  entity name as the hash key for retrieval. Entries in this table
   --  are set by Process_Eliminate_Pragma and read by Check_Eliminated.

   package Elim_Hash_Table is new Static_HTable (
      Header_Num => Header_Num,
      Element    => Element,
      Elmt_Ptr   => Elmt_Ptr,
      Null_Ptr   => Null_Ptr,
      Set_Next   => Hash_Subprograms.Set_Next,
      Next       => Hash_Subprograms.Next,
      Key        => Key,
      Get_Key    => Hash_Subprograms.Get_Key,
      Hash       => Hash_Subprograms.Hash,
      Equal      => Hash_Subprograms.Equal);

   --  The following table records entities for subprograms that are
   --  eliminated, and corresponding eliminate pragmas that caused the
   --  elimination. Entries in this table are set by Check_Eliminated
   --  and read by Eliminate_Error_Msg.

   type Elim_Entity_Entry is record
      Prag : Node_Id;
      Subp : Entity_Id;
   end record;

   package Elim_Entities is new Table.Table (
     Table_Component_Type => Elim_Entity_Entry,
     Table_Index_Type     => Name_Id'Base,
     Table_Low_Bound      => First_Name_Id,
     Table_Initial        => 50,
     Table_Increment      => 200,
     Table_Name           => "Elim_Entries");

   ----------------------
   -- Check_Eliminated --
   ----------------------

   procedure Check_Eliminated (E : Entity_Id) is
      Elmt : Access_Elim_Data;
      Scop : Entity_Id;
      Form : Entity_Id;

      function Original_Chars (S : Entity_Id) return Name_Id;
      --  If the candidate subprogram is a protected operation of a single
      --  protected object, the scope of the operation is the created
      --  protected type, and we have to retrieve the original name of
      --  the object.

      --------------------
      -- Original_Chars --
      --------------------

      function Original_Chars (S : Entity_Id) return Name_Id is
      begin
         if Ekind (S) /= E_Protected_Type
           or else Comes_From_Source (S)
         then
            return Chars (S);
         else
            return Chars (Defining_Identifier (Original_Node (Parent (S))));
         end if;
      end Original_Chars;

   --  Start of processing for Check_Eliminated

   begin
      if No_Elimination then
         return;

      --  Elimination of objects and types is not implemented yet

      elsif Ekind (E) not in Subprogram_Kind then
         return;
      end if;

      --  Loop through homonyms for this key

      Elmt := Elim_Hash_Table.Get (Chars (E));
      while Elmt /= null loop
         declare
            procedure Set_Eliminated;
            --  Set current subprogram entity as eliminated

            --------------------
            -- Set_Eliminated --
            --------------------

            procedure Set_Eliminated is
            begin
               --  Never try to eliminate dispatching operation, since we
               --  can't properly process the eliminated result. This could
               --  be fixed, but is not worth it.

               if not Is_Dispatching_Operation (E) then
                  Set_Is_Eliminated (E);
                  Elim_Entities.Append ((Prag => Elmt.Prag, Subp => E));
               end if;
            end Set_Eliminated;

         begin
            --  First we check that the name of the entity matches

            if Elmt.Entity_Name /= Chars (E) then
               goto Continue;
            end if;

            --  Then we need to see if the static scope matches within the
            --  compilation unit.

            --  At the moment, gnatelim does not consider block statements as
            --  scopes (even if a block is named)

            Scop := Scope (E);
            while Ekind (Scop) = E_Block loop
               Scop := Scope (Scop);
            end loop;

            if Elmt.Entity_Scope /= null then
               for J in reverse Elmt.Entity_Scope'Range loop
                  if Elmt.Entity_Scope (J) /= Original_Chars (Scop) then
                     goto Continue;
                  end if;

                  Scop := Scope (Scop);
                  while Ekind (Scop) = E_Block loop
                     Scop := Scope (Scop);
                  end loop;

                  if not Is_Compilation_Unit (Scop) and then J = 1 then
                     goto Continue;
                  end if;
               end loop;
            end if;

            --  Now see if compilation unit matches

            for J in reverse Elmt.Unit_Name'Range loop
               if Elmt.Unit_Name (J) /= Chars (Scop) then
                  goto Continue;
               end if;

               Scop := Scope (Scop);
               while Ekind (Scop) = E_Block loop
                  Scop := Scope (Scop);
               end loop;

               if Scop /= Standard_Standard and then J = 1 then
                  goto Continue;
               end if;
            end loop;

            if Scop /= Standard_Standard then
               goto Continue;
            end if;

            --  Check for case of given entity is a library level subprogram
            --  and we have the single parameter Eliminate case, a match!

            if Is_Compilation_Unit (E)
              and then Is_Subprogram (E)
              and then No (Elmt.Entity_Node)
            then
               Set_Eliminated;
               return;

               --  Check for case of type or object with two parameter case

            elsif (Is_Type (E) or else Is_Object (E))
              and then Elmt.Result_Type = No_Name
              and then Elmt.Parameter_Types = null
            then
               Set_Eliminated;
               return;

            --  Check for case of subprogram

            elsif Ekind (E) = E_Function
              or else Ekind (E) = E_Procedure
            then
               --  If Source_Location present, then see if it matches

               if Elmt.Source_Location /= No_Name then
                  Get_Name_String (Elmt.Source_Location);

                  declare
                     Sloc_Trace : constant String :=
                                    Name_Buffer (1 .. Name_Len);

                     Idx : Natural := Sloc_Trace'First;
                     --  Index in Sloc_Trace, if equals to 0, then we have
                     --  completely traversed Sloc_Trace

                     Last : constant Natural := Sloc_Trace'Last;

                     P      : Source_Ptr;
                     Sindex : Source_File_Index;

                     function File_Name_Match return Boolean;
                     --  This function is supposed to be called when Idx points
                     --  to the beginning of the new file name, and Name_Buffer
                     --  is set to contain the name of the proper source file
                     --  from the chain corresponding to the Sloc of E. First
                     --  it checks that these two files have the same name. If
                     --  this check is successful, moves Idx to point to the
                     --  beginning of the column number.

                     function Line_Num_Match return Boolean;
                     --  This function is supposed to be called when Idx points
                     --  to the beginning of the column number, and P is
                     --  set to point to the proper Sloc the chain
                     --  corresponding to the Sloc of E. First it checks that
                     --  the line number Idx points on and the line number
                     --  corresponding to P are the same. If this check is
                     --  successful, moves Idx to point to the beginning of
                     --  the next file name in Sloc_Trace. If there is no file
                     --  name any more, Idx is set to 0.

                     function Different_Trace_Lengths return Boolean;
                     --  From Idx and P, defines if there are in both traces
                     --  more element(s) in the instantiation chains. Returns
                     --  False if one trace contains more element(s), but
                     --  another does not. If both traces contains more
                     --  elements (that is, the function returns False), moves
                     --  P ahead in the chain corresponding to E, recomputes
                     --  Sindex and sets the name of the corresponding file in
                     --  Name_Buffer

                     function Skip_Spaces return Natural;
                     --  If Sloc_Trace (Idx) is not space character, returns
                     --  Idx. Otherwise returns the index of the nearest
                     --  non-space character in Sloc_Trace to the right of
                     --  Idx. Returns 0 if there is no such character.

                     -----------------------------
                     -- Different_Trace_Lengths --
                     -----------------------------

                     function Different_Trace_Lengths return Boolean is
                     begin
                        P := Instantiation (Sindex);

                        if (P = No_Location and then Idx /= 0)
                          or else
                           (P /= No_Location and then Idx = 0)
                        then
                           return True;

                        else
                           if P /= No_Location then
                              Sindex := Get_Source_File_Index (P);
                              Get_Name_String (File_Name (Sindex));
                           end if;

                           return False;
                        end if;
                     end Different_Trace_Lengths;

                     ---------------------
                     -- File_Name_Match --
                     ---------------------

                     function File_Name_Match return Boolean is
                        Tmp_Idx : Natural;
                        End_Idx : Natural;

                     begin
                        if Idx = 0 then
                           return False;
                        end if;

                        --  Find first colon. If no colon, then return False.
                        --  If there is a colon, Tmp_Idx is set to point just
                        --  before the colon.

                        Tmp_Idx := Idx - 1;
                        loop
                           if Tmp_Idx >= Last then
                              return False;
                           elsif Sloc_Trace (Tmp_Idx + 1) = ':' then
                              exit;
                           else
                              Tmp_Idx := Tmp_Idx + 1;
                           end if;
                        end loop;

                        --  Find last non-space before this colon. If there
                        --  is no no space character before this colon, then
                        --  return False. Otherwise, End_Idx set to point to
                        --  this non-space character.

                        End_Idx := Tmp_Idx;
                        loop
                           if End_Idx < Idx then
                              return False;
                           elsif Sloc_Trace (End_Idx) /= ' ' then
                              exit;
                           else
                              End_Idx := End_Idx - 1;
                           end if;
                        end loop;

                        --  Now see if file name matches what is in Name_Buffer
                        --  and if so, step Idx past it and return True. If the
                        --  name does not match, return False.

                        if Sloc_Trace (Idx .. End_Idx) =
                           Name_Buffer (1 .. Name_Len)
                        then
                           Idx := Tmp_Idx + 2;
                           Idx := Skip_Spaces;
                           return True;
                        else
                           return False;
                        end if;
                     end File_Name_Match;

                     --------------------
                     -- Line_Num_Match --
                     --------------------

                     function Line_Num_Match return Boolean is
                        N : Int := 0;

                     begin
                        if Idx = 0 then
                           return False;
                        end if;

                        while Idx <= Last
                           and then Sloc_Trace (Idx) in '0' .. '9'
                        loop
                           N := N * 10 +
                            (Character'Pos (Sloc_Trace (Idx)) -
                             Character'Pos ('0'));
                           Idx := Idx + 1;
                        end loop;

                        if Get_Physical_Line_Number (P) =
                           Physical_Line_Number (N)
                        then
                           while Idx <= Last and then
                              Sloc_Trace (Idx) /= '['
                           loop
                              Idx := Idx + 1;
                           end loop;

                           if Idx <= Last and then
                             Sloc_Trace (Idx) = '['
                           then
                              Idx := Idx + 1;
                              Idx := Skip_Spaces;
                           else
                              Idx := 0;
                           end if;

                           return True;

                        else
                           return False;
                        end if;
                     end Line_Num_Match;

                     -----------------
                     -- Skip_Spaces --
                     -----------------

                     function Skip_Spaces return Natural is
                        Res : Natural;

                     begin
                        Res := Idx;
                        while Sloc_Trace (Res) = ' ' loop
                           Res := Res + 1;

                           if Res > Last then
                              Res := 0;
                              exit;
                           end if;
                        end loop;

                        return Res;
                     end Skip_Spaces;

                  begin
                     P := Sloc (E);
                     Sindex := Get_Source_File_Index (P);
                     Get_Name_String (File_Name (Sindex));

                     Idx := Skip_Spaces;
                     while Idx > 0 loop
                        if not File_Name_Match then
                           goto Continue;
                        elsif not Line_Num_Match then
                           goto Continue;
                        end if;

                        if Different_Trace_Lengths then
                           goto Continue;
                        end if;
                     end loop;
                  end;
               end if;

               --  If we have a Result_Type, then we must have a function
               --  with the proper result type

               if Elmt.Result_Type /= No_Name then
                  if Ekind (E) /= E_Function
                    or else Chars (Etype (E)) /= Elmt.Result_Type
                  then
                     goto Continue;
                  end if;
               end if;

               --  If we have Parameter_Types, they must match

               if Elmt.Parameter_Types /= null then
                  Form := First_Formal (E);

                  if No (Form)
                    and then Elmt.Parameter_Types'Length = 1
                    and then Elmt.Parameter_Types (1) = No_Name
                  then
                     --  Parameterless procedure matches

                     null;

                  elsif Elmt.Parameter_Types = null then
                     goto Continue;

                  else
                     for J in Elmt.Parameter_Types'Range loop
                        if No (Form)
                          or else
                            Chars (Etype (Form)) /= Elmt.Parameter_Types (J)
                        then
                           goto Continue;
                        else
                           Next_Formal (Form);
                        end if;
                     end loop;

                     if Present (Form) then
                        goto Continue;
                     end if;
                  end if;
               end if;

               --  If we fall through, this is match

               Set_Eliminated;
               return;
            end if;
         end;

      <<Continue>>
         Elmt := Elmt.Homonym;
      end loop;

      return;
   end Check_Eliminated;

   -------------------------
   -- Eliminate_Error_Msg --
   -------------------------

   procedure Eliminate_Error_Msg (N : Node_Id; E : Entity_Id) is
   begin
      for J in Elim_Entities.First .. Elim_Entities.Last loop
         if E = Elim_Entities.Table (J).Subp then
            Error_Msg_Sloc := Sloc (Elim_Entities.Table (J).Prag);
            Error_Msg_NE ("cannot call subprogram & eliminated #", N, E);
            return;
         end if;
      end loop;

      --  Should never fall through, since entry should be in table

      raise Program_Error;
   end Eliminate_Error_Msg;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize is
   begin
      Elim_Hash_Table.Reset;
      Elim_Entities.Init;
      No_Elimination := True;
   end Initialize;

   ------------------------------
   -- Process_Eliminate_Pragma --
   ------------------------------

   procedure Process_Eliminate_Pragma
     (Pragma_Node         : Node_Id;
      Arg_Unit_Name       : Node_Id;
      Arg_Entity          : Node_Id;
      Arg_Parameter_Types : Node_Id;
      Arg_Result_Type     : Node_Id;
      Arg_Source_Location : Node_Id)
   is
      Data : constant Access_Elim_Data := new Elim_Data;
      --  Build result data here

      Elmt : Access_Elim_Data;

      Num_Names : Nat := 0;
      --  Number of names in unit name

      Lit       : Node_Id;
      Arg_Ent   : Entity_Id;
      Arg_Uname : Node_Id;

      function OK_Selected_Component (N : Node_Id) return Boolean;
      --  Test if N is a selected component with all identifiers, or a
      --  selected component whose selector is an operator symbol. As a
      --  side effect if result is True, sets Num_Names to the number
      --  of names present (identifiers and operator if any).

      ---------------------------
      -- OK_Selected_Component --
      ---------------------------

      function OK_Selected_Component (N : Node_Id) return Boolean is
      begin
         if Nkind (N) = N_Identifier
           or else Nkind (N) = N_Operator_Symbol
         then
            Num_Names := Num_Names + 1;
            return True;

         elsif Nkind (N) = N_Selected_Component then
            return OK_Selected_Component (Prefix (N))
              and then OK_Selected_Component (Selector_Name (N));

         else
            return False;
         end if;
      end OK_Selected_Component;

   --  Start of processing for Process_Eliminate_Pragma

   begin
      Data.Prag := Pragma_Node;
      Error_Msg_Name_1 := Name_Eliminate;

      --  Process Unit_Name argument

      if Nkind (Arg_Unit_Name) = N_Identifier then
         Data.Unit_Name := new Names'(1 => Chars (Arg_Unit_Name));
         Num_Names := 1;

      elsif OK_Selected_Component (Arg_Unit_Name) then
         Data.Unit_Name := new Names (1 .. Num_Names);

         Arg_Uname := Arg_Unit_Name;
         for J in reverse 2 .. Num_Names loop
            Data.Unit_Name (J) := Chars (Selector_Name (Arg_Uname));
            Arg_Uname := Prefix (Arg_Uname);
         end loop;

         Data.Unit_Name (1) := Chars (Arg_Uname);

      else
         Error_Msg_N
           ("wrong form for Unit_Name parameter of pragma%", Arg_Unit_Name);
         return;
      end if;

      --  Process Entity argument

      if Present (Arg_Entity) then
         Num_Names := 0;

         if Nkind (Arg_Entity) = N_Identifier
           or else Nkind (Arg_Entity) = N_Operator_Symbol
         then
            Data.Entity_Name  := Chars (Arg_Entity);
            Data.Entity_Node  := Arg_Entity;
            Data.Entity_Scope := null;

         elsif OK_Selected_Component (Arg_Entity) then
            Data.Entity_Scope := new Names (1 .. Num_Names - 1);
            Data.Entity_Name  := Chars (Selector_Name (Arg_Entity));
            Data.Entity_Node  := Arg_Entity;

            Arg_Ent := Prefix (Arg_Entity);
            for J in reverse 2 .. Num_Names - 1 loop
               Data.Entity_Scope (J) := Chars (Selector_Name (Arg_Ent));
               Arg_Ent := Prefix (Arg_Ent);
            end loop;

            Data.Entity_Scope (1) := Chars (Arg_Ent);

         elsif Is_Config_Static_String (Arg_Entity) then
            Data.Entity_Name := Name_Find;
            Data.Entity_Node := Arg_Entity;

         else
            return;
         end if;
      else
         Data.Entity_Node := Empty;
         Data.Entity_Name := Data.Unit_Name (Num_Names);
      end if;

      --  Process Parameter_Types argument

      if Present (Arg_Parameter_Types) then

         --  Here for aggregate case

         if Nkind (Arg_Parameter_Types) = N_Aggregate then
            Data.Parameter_Types :=
              new Names
                (1 .. List_Length (Expressions (Arg_Parameter_Types)));

            Lit := First (Expressions (Arg_Parameter_Types));
            for J in Data.Parameter_Types'Range loop
               if Is_Config_Static_String (Lit) then
                  Data.Parameter_Types (J) := Name_Find;
                  Next (Lit);
               else
                  return;
               end if;
            end loop;

         --  Otherwise we must have case of one name, which looks like a
         --  parenthesized literal rather than an aggregate.

         elsif Paren_Count (Arg_Parameter_Types) /= 1 then
            Error_Msg_N
              ("wrong form for argument of pragma Eliminate",
               Arg_Parameter_Types);
            return;

         elsif Is_Config_Static_String (Arg_Parameter_Types) then
            String_To_Name_Buffer (Strval (Arg_Parameter_Types));

            if Name_Len = 0 then

               --  Parameterless procedure

               Data.Parameter_Types := new Names'(1 => No_Name);

            else
               Data.Parameter_Types := new Names'(1 => Name_Find);
            end if;

         else
            return;
         end if;
      end if;

      --  Process Result_Types argument

      if Present (Arg_Result_Type) then
         if Is_Config_Static_String (Arg_Result_Type) then
            Data.Result_Type := Name_Find;
         else
            return;
         end if;

      --  Here if no Result_Types argument

      else
         Data.Result_Type := No_Name;
      end if;

      --  Process Source_Location argument

      if Present (Arg_Source_Location) then
         if Is_Config_Static_String (Arg_Source_Location) then
            Data.Source_Location := Name_Find;
         else
            return;
         end if;
      else
         Data.Source_Location := No_Name;
      end if;

      Elmt := Elim_Hash_Table.Get (Hash_Subprograms.Get_Key (Data));

      --  If we already have an entry with this same key, then link
      --  it into the chain of entries for this key.

      if Elmt /= null then
         Data.Homonym := Elmt.Homonym;
         Elmt.Homonym := Data;

      --  Otherwise create a new entry

      else
         Elim_Hash_Table.Set (Data);
      end if;

      No_Elimination := False;
   end Process_Eliminate_Pragma;

end Sem_Elim;