aboutsummaryrefslogtreecommitdiff
path: root/gdb/macrotab.c
blob: f2012dae1ad69f6837ccd2fcb663c89363e66751 (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
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
/* C preprocessor macro tables for GDB.
   Copyright (C) 2002-2024 Free Software Foundation, Inc.
   Contributed by Red Hat, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT 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
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "gdbsupport/gdb_obstack.h"
#include "gdbsupport/pathstuff.h"
#include "splay-tree.h"
#include "filenames.h"
#include "symtab.h"
#include "symfile.h"
#include "objfiles.h"
#include "macrotab.h"
#include "bcache.h"
#include "complaints.h"
#include "macroexp.h"


/* The macro table structure.  */

struct macro_table
{
  /* The obstack this table's data should be allocated in, or zero if
     we should use xmalloc.  */
  struct obstack *obstack;

  /* The bcache we should use to hold macro names, argument names, and
     definitions, or zero if we should use xmalloc.  */
  gdb::bcache *bcache;

  /* The main source file for this compilation unit --- the one whose
     name was given to the compiler.  This is the root of the
     #inclusion tree; everything else is #included from here.  */
  struct macro_source_file *main_source;

  /* Backlink to containing compilation unit, or NULL if there isn't one.  */
  struct compunit_symtab *compunit_symtab;

  /* True if macros in this table can be redefined without issuing an
     error.  */
  int redef_ok;

  /* The table of macro definitions.  This is a splay tree (an ordered
     binary tree that stays balanced, effectively), sorted by macro
     name.  Where a macro gets defined more than once (presumably with
     an #undefinition in between), we sort the definitions by the
     order they would appear in the preprocessor's output.  That is,
     if `a.c' #includes `m.h' and then #includes `n.h', and both
     header files #define X (with an #undef somewhere in between),
     then the definition from `m.h' appears in our splay tree before
     the one from `n.h'.

     The splay tree's keys are `struct macro_key' pointers;
     the values are `struct macro_definition' pointers.

     The splay tree, its nodes, and the keys and values are allocated
     in obstack, if it's non-zero, or with xmalloc otherwise.  The
     macro names, argument names, argument name arrays, and definition
     strings are all allocated in bcache, if non-zero, or with xmalloc
     otherwise.  */
  splay_tree definitions;
};



/* Allocation and freeing functions.  */

/* Allocate SIZE bytes of memory appropriately for the macro table T.
   This just checks whether T has an obstack, or whether its pieces
   should be allocated with xmalloc.  */
static void *
macro_alloc (int size, struct macro_table *t)
{
  if (t->obstack)
    return obstack_alloc (t->obstack, size);
  else
    return xmalloc (size);
}


static void
macro_free (void *object, struct macro_table *t)
{
  if (t->obstack)
    /* There are cases where we need to remove entries from a macro
       table, even when reading debugging information.  This should be
       rare, and there's no easy way to free arbitrary data from an
       obstack, so we just leak it.  */
    ;
  else
    xfree (object);
}


/* If the macro table T has a bcache, then cache the LEN bytes at ADDR
   there, and return the cached copy.  Otherwise, just xmalloc a copy
   of the bytes, and return a pointer to that.  */
static const void *
macro_bcache (struct macro_table *t, const void *addr, int len)
{
  if (t->bcache)
    return t->bcache->insert (addr, len);
  else
    {
      void *copy = xmalloc (len);

      memcpy (copy, addr, len);
      return copy;
    }
}


/* If the macro table T has a bcache, cache the null-terminated string
   S there, and return a pointer to the cached copy.  Otherwise,
   xmalloc a copy and return that.  */
static const char *
macro_bcache_str (struct macro_table *t, const char *s)
{
  return (const char *) macro_bcache (t, s, strlen (s) + 1);
}


/* Free a possibly bcached object OBJ.  That is, if the macro table T
   has a bcache, do nothing; otherwise, xfree OBJ.  */
static void
macro_bcache_free (struct macro_table *t, void *obj)
{
  if (t->bcache)
    /* There are cases where we need to remove entries from a macro
       table, even when reading debugging information.  This should be
       rare, and there's no easy way to free data from a bcache, so we
       just leak it.  */
    ;
  else
    xfree (obj);
}



/* Macro tree keys, w/their comparison, allocation, and freeing functions.  */

/* A key in the splay tree.  */
struct macro_key
{
  /* The table we're in.  We only need this in order to free it, since
     the splay tree library's key and value freeing functions require
     that the key or value contain all the information needed to free
     themselves.  */
  struct macro_table *table;

  /* The name of the macro.  This is in the table's bcache, if it has
     one.  */
  const char *name;

  /* The source file and line number where the definition's scope
     begins.  This is also the line of the definition itself.  */
  struct macro_source_file *start_file;
  int start_line;

  /* The first source file and line after the definition's scope.
     (That is, the scope does not include this endpoint.)  If end_file
     is zero, then the definition extends to the end of the
     compilation unit.  */
  struct macro_source_file *end_file;
  int end_line;
};


/* Return the #inclusion depth of the source file FILE.  This is the
   number of #inclusions it took to reach this file.  For the main
   source file, the #inclusion depth is zero; for a file it #includes
   directly, the depth would be one; and so on.  */
static int
inclusion_depth (struct macro_source_file *file)
{
  int depth;

  for (depth = 0; file->included_by; depth++)
    file = file->included_by;

  return depth;
}


/* Compare two source locations (from the same compilation unit).
   This is part of the comparison function for the tree of
   definitions.

   LINE1 and LINE2 are line numbers in the source files FILE1 and
   FILE2.  Return a value:
   - less than zero if {LINE,FILE}1 comes before {LINE,FILE}2,
   - greater than zero if {LINE,FILE}1 comes after {LINE,FILE}2, or
   - zero if they are equal.

   When the two locations are in different source files --- perhaps
   one is in a header, while another is in the main source file --- we
   order them by where they would appear in the fully pre-processed
   sources, where all the #included files have been substituted into
   their places.  */
static int
compare_locations (struct macro_source_file *file1, int line1, 
		   struct macro_source_file *file2, int line2)
{
  /* We want to treat positions in an #included file as coming *after*
     the line containing the #include, but *before* the line after the
     include.  As we walk up the #inclusion tree toward the main
     source file, we update fileX and lineX as we go; includedX
     indicates whether the original position was from the #included
     file.  */
  int included1 = 0;
  int included2 = 0;

  /* If a file is zero, that means "end of compilation unit."  Handle
     that specially.  */
  if (! file1)
    {
      if (! file2)
	return 0;
      else
	return 1;
    }
  else if (! file2)
    return -1;

  /* If the two files are not the same, find their common ancestor in
     the #inclusion tree.  */
  if (file1 != file2)
    {
      /* If one file is deeper than the other, walk up the #inclusion
	 chain until the two files are at least at the same *depth*.
	 Then, walk up both files in synchrony until they're the same
	 file.  That file is the common ancestor.  */
      int depth1 = inclusion_depth (file1);
      int depth2 = inclusion_depth (file2);

      /* Only one of these while loops will ever execute in any given
	 case.  */
      while (depth1 > depth2)
	{
	  line1 = file1->included_at_line;
	  file1 = file1->included_by;
	  included1 = 1;
	  depth1--;
	}
      while (depth2 > depth1)
	{
	  line2 = file2->included_at_line;
	  file2 = file2->included_by;
	  included2 = 1;
	  depth2--;
	}

      /* Now both file1 and file2 are at the same depth.  Walk toward
	 the root of the tree until we find where the branches meet.  */
      while (file1 != file2)
	{
	  line1 = file1->included_at_line;
	  file1 = file1->included_by;
	  /* At this point, we know that the case the includedX flags
	     are trying to deal with won't come up, but we'll just
	     maintain them anyway.  */
	  included1 = 1;

	  line2 = file2->included_at_line;
	  file2 = file2->included_by;
	  included2 = 1;

	  /* Sanity check.  If file1 and file2 are really from the
	     same compilation unit, then they should both be part of
	     the same tree, and this shouldn't happen.  */
	  gdb_assert (file1 && file2);
	}
    }

  /* Now we've got two line numbers in the same file.  */
  if (line1 == line2)
    {
      /* They can't both be from #included files.  Then we shouldn't
	 have walked up this far.  */
      gdb_assert (! included1 || ! included2);

      /* Any #included position comes after a non-#included position
	 with the same line number in the #including file.  */
      if (included1)
	return 1;
      else if (included2)
	return -1;
      else
	return 0;
    }
  else
    return line1 - line2;
}


/* Compare a macro key KEY against NAME, the source file FILE, and
   line number LINE.

   Sort definitions by name; for two definitions with the same name,
   place the one whose definition comes earlier before the one whose
   definition comes later.

   Return -1, 0, or 1 if key comes before, is identical to, or comes
   after NAME, FILE, and LINE.  */
static int
key_compare (struct macro_key *key,
	     const char *name, struct macro_source_file *file, int line)
{
  int names = strcmp (key->name, name);

  if (names)
    return names;

  return compare_locations (key->start_file, key->start_line,
			    file, line);
}


/* The macro tree comparison function, typed for the splay tree
   library's happiness.  */
static int
macro_tree_compare (splay_tree_key untyped_key1,
		    splay_tree_key untyped_key2)
{
  struct macro_key *key1 = (struct macro_key *) untyped_key1;
  struct macro_key *key2 = (struct macro_key *) untyped_key2;

  return key_compare (key1, key2->name, key2->start_file, key2->start_line);
}


/* Construct a new macro key node for a macro in table T whose name is
   NAME, and whose scope starts at LINE in FILE; register the name in
   the bcache.  */
static struct macro_key *
new_macro_key (struct macro_table *t,
	       const char *name,
	       struct macro_source_file *file,
	       int line)
{
  struct macro_key *k = (struct macro_key *) macro_alloc (sizeof (*k), t);

  memset (k, 0, sizeof (*k));
  k->table = t;
  k->name = macro_bcache_str (t, name);
  k->start_file = file;
  k->start_line = line;
  k->end_file = 0;

  return k;
}


static void
macro_tree_delete_key (void *untyped_key)
{
  struct macro_key *key = (struct macro_key *) untyped_key;

  macro_bcache_free (key->table, (char *) key->name);
  macro_free (key, key->table);
}



/* Building and querying the tree of #included files.  */


/* Allocate and initialize a new source file structure.  */
static struct macro_source_file *
new_source_file (struct macro_table *t,
		 const char *filename)
{
  /* Get space for the source file structure itself.  */
  struct macro_source_file *f
    = (struct macro_source_file *) macro_alloc (sizeof (*f), t);

  memset (f, 0, sizeof (*f));
  f->table = t;
  f->filename = macro_bcache_str (t, filename);
  f->includes = 0;

  return f;
}


/* Free a source file, and all the source files it #included.  */
static void
free_macro_source_file (struct macro_source_file *src)
{
  struct macro_source_file *child, *next_child;

  /* Free this file's children.  */
  for (child = src->includes; child; child = next_child)
    {
      next_child = child->next_included;
      free_macro_source_file (child);
    }

  macro_bcache_free (src->table, (char *) src->filename);
  macro_free (src, src->table);
}


struct macro_source_file *
macro_set_main (struct macro_table *t,
		const char *filename)
{
  /* You can't change a table's main source file.  What would that do
     to the tree?  */
  gdb_assert (! t->main_source);

  t->main_source = new_source_file (t, filename);

  return t->main_source;
}


struct macro_source_file *
macro_main (struct macro_table *t)
{
  gdb_assert (t->main_source);

  return t->main_source;
}


void
macro_allow_redefinitions (struct macro_table *t)
{
  gdb_assert (! t->obstack);
  t->redef_ok = 1;
}


struct macro_source_file *
macro_include (struct macro_source_file *source,
	       int line,
	       const char *included)
{
  struct macro_source_file *newobj;
  struct macro_source_file **link;

  /* Find the right position in SOURCE's `includes' list for the new
     file.  Skip inclusions at earlier lines, until we find one at the
     same line or later --- or until the end of the list.  */
  for (link = &source->includes;
       *link && (*link)->included_at_line < line;
       link = &(*link)->next_included)
    ;

  /* Did we find another file already #included at the same line as
     the new one?  */
  if (*link && line == (*link)->included_at_line)
    {
      /* This means the compiler is emitting bogus debug info.  (GCC
	 circa March 2002 did this.)  It also means that the splay
	 tree ordering function, macro_tree_compare, will abort,
	 because it can't tell which #inclusion came first.  But GDB
	 should tolerate bad debug info.  So:

	 First, squawk.  */

      std::string link_fullname = macro_source_fullname (*link);
      std::string source_fullname = macro_source_fullname (source);
      complaint (_("both `%s' and `%s' allegedly #included at %s:%d"),
		 included, link_fullname.c_str (), source_fullname.c_str (),
		 line);

      /* Now, choose a new, unoccupied line number for this
	 #inclusion, after the alleged #inclusion line.  */
      while (*link && line == (*link)->included_at_line)
	{
	  /* This line number is taken, so try the next line.  */
	  line++;
	  link = &(*link)->next_included;
	}
    }

  /* At this point, we know that LINE is an unused line number, and
     *LINK points to the entry an #inclusion at that line should
     precede.  */
  newobj = new_source_file (source->table, included);
  newobj->included_by = source;
  newobj->included_at_line = line;
  newobj->next_included = *link;
  *link = newobj;

  return newobj;
}


struct macro_source_file *
macro_lookup_inclusion (struct macro_source_file *source, const char *name)
{
  /* Is SOURCE itself named NAME?  */
  if (filename_cmp (name, source->filename) == 0)
    return source;

  /* It's not us.  Try all our children, and return the lowest.  */
  {
    struct macro_source_file *child;
    struct macro_source_file *best = NULL;
    int best_depth = 0;

    for (child = source->includes; child; child = child->next_included)
      {
	struct macro_source_file *result
	  = macro_lookup_inclusion (child, name);

	if (result)
	  {
	    int result_depth = inclusion_depth (result);

	    if (! best || result_depth < best_depth)
	      {
		best = result;
		best_depth = result_depth;
	      }
	  }
      }

    return best;
  }
}



/* Registering and looking up macro definitions.  */


/* Construct a definition for a macro in table T.  Cache all strings,
   and the macro_definition structure itself, in T's bcache.  */
static struct macro_definition *
new_macro_definition (struct macro_table *t,
		      enum macro_kind kind,
		      int argc, const char **argv,
		      const char *replacement)
{
  struct macro_definition *d
    = (struct macro_definition *) macro_alloc (sizeof (*d), t);

  memset (d, 0, sizeof (*d));
  d->table = t;
  d->kind = kind;
  d->replacement = macro_bcache_str (t, replacement);
  d->argc = argc;

  if (kind == macro_function_like)
    {
      int i;
      const char **cached_argv;
      int cached_argv_size = argc * sizeof (*cached_argv);

      /* Bcache all the arguments.  */
      cached_argv = (const char **) alloca (cached_argv_size);
      for (i = 0; i < argc; i++)
	cached_argv[i] = macro_bcache_str (t, argv[i]);

      /* Now bcache the array of argument pointers itself.  */
      d->argv = ((const char * const *)
		 macro_bcache (t, cached_argv, cached_argv_size));
    }

  /* We don't bcache the entire definition structure because it's got
     a pointer to the macro table in it; since each compilation unit
     has its own macro table, you'd only get bcache hits for identical
     definitions within a compilation unit, which seems unlikely.

     "So, why do macro definitions have pointers to their macro tables
     at all?"  Well, when the splay tree library wants to free a
     node's value, it calls the value freeing function with nothing
     but the value itself.  It makes the (apparently reasonable)
     assumption that the value carries enough information to free
     itself.  But not all macro tables have bcaches, so not all macro
     definitions would be bcached.  There's no way to tell whether a
     given definition is bcached without knowing which table the
     definition belongs to.  ...  blah.  The thing's only sixteen
     bytes anyway, and we can still bcache the name, args, and
     definition, so we just don't bother bcaching the definition
     structure itself.  */
  return d;
}


/* Free a macro definition.  */
static void
macro_tree_delete_value (void *untyped_definition)
{
  struct macro_definition *d = (struct macro_definition *) untyped_definition;
  struct macro_table *t = d->table;

  if (d->kind == macro_function_like)
    {
      int i;

      for (i = 0; i < d->argc; i++)
	macro_bcache_free (t, (char *) d->argv[i]);
      macro_bcache_free (t, (char **) d->argv);
    }
  
  macro_bcache_free (t, (char *) d->replacement);
  macro_free (d, t);
}


/* Find the splay tree node for the definition of NAME at LINE in
   SOURCE, or zero if there is none.  */
static splay_tree_node
find_definition (const char *name,
		 struct macro_source_file *file,
		 int line)
{
  struct macro_table *t = file->table;
  splay_tree_node n;

  /* Construct a macro_key object, just for the query.  */
  struct macro_key query;

  query.name = name;
  query.start_file = file;
  query.start_line = line;
  query.end_file = NULL;

  n = splay_tree_lookup (t->definitions, (splay_tree_key) &query);
  if (! n)
    {
      /* It's okay for us to do two queries like this: the real work
	 of the searching is done when we splay, and splaying the tree
	 a second time at the same key is a constant time operation.
	 If this still bugs you, you could always just extend the
	 splay tree library with a predecessor-or-equal operation, and
	 use that.  */
      splay_tree_node pred = splay_tree_predecessor (t->definitions,
						     (splay_tree_key) &query);
     
      if (pred)
	{
	  /* Make sure this predecessor actually has the right name.
	     We just want to search within a given name's definitions.  */
	  struct macro_key *found = (struct macro_key *) pred->key;

	  if (strcmp (found->name, name) == 0)
	    n = pred;
	}
    }

  if (n)
    {
      struct macro_key *found = (struct macro_key *) n->key;

      /* Okay, so this definition has the right name, and its scope
	 begins before the given source location.  But does its scope
	 end after the given source location?  */
      if (compare_locations (file, line, found->end_file, found->end_line) < 0)
	return n;
      else
	return 0;
    }
  else
    return 0;
}


/* If NAME already has a definition in scope at LINE in SOURCE, return
   the key.  If the old definition is different from the definition
   given by KIND, ARGC, ARGV, and REPLACEMENT, complain, too.
   Otherwise, return zero.  (ARGC and ARGV are meaningless unless KIND
   is `macro_function_like'.)  */
static struct macro_key *
check_for_redefinition (struct macro_source_file *source, int line,
			const char *name, enum macro_kind kind,
			int argc, const char **argv,
			const char *replacement)
{
  splay_tree_node n = find_definition (name, source, line);

  if (n)
    {
      struct macro_key *found_key = (struct macro_key *) n->key;
      struct macro_definition *found_def
	= (struct macro_definition *) n->value;
      int same = 1;

      /* Is this definition the same as the existing one?
	 According to the standard, this comparison needs to be done
	 on lists of tokens, not byte-by-byte, as we do here.  But
	 that's too hard for us at the moment, and comparing
	 byte-by-byte will only yield false negatives (i.e., extra
	 warning messages), not false positives (i.e., unnoticed
	 definition changes).  */
      if (kind != found_def->kind)
	same = 0;
      else if (strcmp (replacement, found_def->replacement))
	same = 0;
      else if (kind == macro_function_like)
	{
	  if (argc != found_def->argc)
	    same = 0;
	  else
	    {
	      int i;

	      for (i = 0; i < argc; i++)
		if (strcmp (argv[i], found_def->argv[i]))
		  same = 0;
	    }
	}

      if (! same)
	{
	  std::string source_fullname = macro_source_fullname (source);
	  std::string found_key_fullname
	    = macro_source_fullname (found_key->start_file);
	  complaint (_("macro `%s' redefined at %s:%d; "
		       "original definition at %s:%d"),
		     name, source_fullname.c_str (), line,
		     found_key_fullname.c_str (),
		     found_key->start_line);
	}

      return found_key;
    }
  else
    return 0;
}

/* A helper function to define a new object-like or function-like macro
   according to KIND.  When KIND is macro_object_like,
   the macro_special_kind must be provided as ARGC, and ARGV must be NULL.
   When KIND is macro_function_like, ARGC and ARGV are giving the function
   arguments.  */

static void
macro_define_internal (struct macro_source_file *source, int line,
		       const char *name, enum macro_kind kind,
		       int argc, const char **argv,
		       const char *replacement)
{
  struct macro_table *t = source->table;
  struct macro_key *k = NULL;
  struct macro_definition *d;

  if (! t->redef_ok)
    k = check_for_redefinition (source, line,
				name, kind,
				argc, argv,
				replacement);

  /* If we're redefining a symbol, and the existing key would be
     identical to our new key, then the splay_tree_insert function
     will try to delete the old definition.  When the definition is
     living on an obstack, this isn't a happy thing.

     Since this only happens in the presence of questionable debug
     info, we just ignore all definitions after the first.  The only
     case I know of where this arises is in GCC's output for
     predefined macros, and all the definitions are the same in that
     case.  */
  if (k && ! key_compare (k, name, source, line))
    return;

  k = new_macro_key (t, name, source, line);
  d = new_macro_definition (t, kind, argc, argv, replacement);
  splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
}

/* A helper function to define a new object-like macro.  */

static void
macro_define_object_internal (struct macro_source_file *source, int line,
			      const char *name, const char *replacement,
			      enum macro_special_kind special_kind)
{
  macro_define_internal (source, line,
			 name, macro_object_like,
			 special_kind, NULL,
			 replacement);
}

void
macro_define_object (struct macro_source_file *source, int line,
		     const char *name, const char *replacement)
{
  macro_define_object_internal (source, line, name, replacement,
				macro_ordinary);
}

/* See macrotab.h.  */

void
macro_define_special (struct macro_table *table)
{
  macro_define_object_internal (table->main_source, -1, "__FILE__", "",
				macro_FILE);
  macro_define_object_internal (table->main_source, -1, "__LINE__", "",
				macro_LINE);
}

void
macro_define_function (struct macro_source_file *source, int line,
		       const char *name, int argc, const char **argv,
		       const char *replacement)
{
  macro_define_internal (source, line,
			 name, macro_function_like,
			 argc, argv,
			 replacement);
}

void
macro_undef (struct macro_source_file *source, int line,
	     const char *name)
{
  splay_tree_node n = find_definition (name, source, line);

  if (n)
    {
      struct macro_key *key = (struct macro_key *) n->key;

      /* If we're removing a definition at exactly the same point that
	 we defined it, then just delete the entry altogether.  GCC
	 4.1.2 will generate DWARF that says to do this if you pass it
	 arguments like '-DFOO -UFOO -DFOO=2'.  */
      if (source == key->start_file
	  && line == key->start_line)
	splay_tree_remove (source->table->definitions, n->key);

      else
	{
	  /* This function is the only place a macro's end-of-scope
	     location gets set to anything other than "end of the
	     compilation unit" (i.e., end_file is zero).  So if this
	     macro already has its end-of-scope set, then we're
	     probably seeing a second #undefinition for the same
	     #definition.  */
	  if (key->end_file)
	    {
	      std::string source_fullname = macro_source_fullname (source);
	      std::string key_fullname = macro_source_fullname (key->end_file);
	      complaint (_("macro '%s' is #undefined twice,"
			   " at %s:%d and %s:%d"),
			 name, source_fullname.c_str (), line,
			 key_fullname.c_str (),
			 key->end_line);
	    }

	  /* Whether or not we've seen a prior #undefinition, wipe out
	     the old ending point, and make this the ending point.  */
	  key->end_file = source;
	  key->end_line = line;
	}
    }
  else
    {
      /* According to the ISO C standard, an #undef for a symbol that
	 has no macro definition in scope is ignored.  So we should
	 ignore it too.  */
#if 0
      complaint (_("no definition for macro `%s' in scope to #undef at %s:%d"),
		 name, source->filename, line);
#endif
    }
}

/* A helper function that rewrites the definition of a special macro,
   when needed.  */

static struct macro_definition *
fixup_definition (const char *filename, int line, struct macro_definition *def)
{
  static gdb::unique_xmalloc_ptr<char> saved_expansion;

  if (def->kind == macro_object_like)
    {
      if (def->argc == macro_FILE)
	{
	  saved_expansion = macro_stringify (filename);
	  def->replacement = saved_expansion.get ();
	}
      else if (def->argc == macro_LINE)
	{
	  saved_expansion = xstrprintf ("%d", line);
	  def->replacement = saved_expansion.get ();
	}
    }

  return def;
}

struct macro_definition *
macro_lookup_definition (struct macro_source_file *source,
			 int line, const char *name)
{
  splay_tree_node n = find_definition (name, source, line);

  if (n)
    {
      std::string source_fullname = macro_source_fullname (source);
      return fixup_definition (source_fullname.c_str (), line,
			       (struct macro_definition *) n->value);
    }
  else
    return 0;
}


struct macro_source_file *
macro_definition_location (struct macro_source_file *source,
			   int line,
			   const char *name,
			   int *definition_line)
{
  splay_tree_node n = find_definition (name, source, line);

  if (n)
    {
      struct macro_key *key = (struct macro_key *) n->key;

      *definition_line = key->start_line;
      return key->start_file;
    }
  else
    return 0;
}


/* The type for callback data for iterating the splay tree in
   macro_for_each and macro_for_each_in_scope.  Only the latter uses
   the FILE and LINE fields.  */
struct macro_for_each_data
{
  gdb::function_view<macro_callback_fn> fn;
  struct macro_source_file *file;
  int line;
};

/* Helper function for macro_for_each.  */
static int
foreach_macro (splay_tree_node node, void *arg)
{
  struct macro_for_each_data *datum = (struct macro_for_each_data *) arg;
  struct macro_key *key = (struct macro_key *) node->key;
  struct macro_definition *def;

  std::string key_fullname = macro_source_fullname (key->start_file);
  def = fixup_definition (key_fullname.c_str (), key->start_line,
			  (struct macro_definition *) node->value);

  datum->fn (key->name, def, key->start_file, key->start_line);
  return 0;
}

/* Call FN for every macro in TABLE.  */
void
macro_for_each (struct macro_table *table,
		gdb::function_view<macro_callback_fn> fn)
{
  struct macro_for_each_data datum;

  datum.fn = fn;
  datum.file = NULL;
  datum.line = 0;
  splay_tree_foreach (table->definitions, foreach_macro, &datum);
}

static int
foreach_macro_in_scope (splay_tree_node node, void *info)
{
  struct macro_for_each_data *datum = (struct macro_for_each_data *) info;
  struct macro_key *key = (struct macro_key *) node->key;
  struct macro_definition *def;

  std::string datum_fullname = macro_source_fullname (datum->file);
  def = fixup_definition (datum_fullname.c_str (), datum->line,
			  (struct macro_definition *) node->value);

  /* See if this macro is defined before the passed-in line, and
     extends past that line.  */
  if (compare_locations (key->start_file, key->start_line,
			 datum->file, datum->line) < 0
      && (!key->end_file
	  || compare_locations (key->end_file, key->end_line,
				datum->file, datum->line) >= 0))
    datum->fn (key->name, def, key->start_file, key->start_line);
  return 0;
}

/* Call FN for every macro is visible in SCOPE.  */
void
macro_for_each_in_scope (struct macro_source_file *file, int line,
			 gdb::function_view<macro_callback_fn> fn)
{
  struct macro_for_each_data datum;

  datum.fn = fn;
  datum.file = file;
  datum.line = line;
  splay_tree_foreach (file->table->definitions,
		      foreach_macro_in_scope, &datum);
}



/* Creating and freeing macro tables.  */


struct macro_table *
new_macro_table (struct obstack *obstack, gdb::bcache *b,
		 struct compunit_symtab *cust)
{
  struct macro_table *t;

  /* First, get storage for the `struct macro_table' itself.  */
  if (obstack)
    t = XOBNEW (obstack, struct macro_table);
  else
    t = XNEW (struct macro_table);

  memset (t, 0, sizeof (*t));
  t->obstack = obstack;
  t->bcache = b;
  t->main_source = NULL;
  t->compunit_symtab = cust;
  t->redef_ok = 0;
  t->definitions = (splay_tree_new_with_allocator
		    (macro_tree_compare,
		     ((splay_tree_delete_key_fn) macro_tree_delete_key),
		     ((splay_tree_delete_value_fn) macro_tree_delete_value),
		     ((splay_tree_allocate_fn) macro_alloc),
		     ((splay_tree_deallocate_fn) macro_free),
		     t));
  
  return t;
}


void
free_macro_table (struct macro_table *table)
{
  /* Free the source file tree.  */
  free_macro_source_file (table->main_source);

  /* Free the table of macro definitions.  */
  splay_tree_delete (table->definitions);
}

/* See macrotab.h for the comment.  */

std::string
macro_source_fullname (struct macro_source_file *file)
{
  const char *comp_dir = NULL;

  if (file->table->compunit_symtab != NULL)
    comp_dir = file->table->compunit_symtab->dirname ();

  if (comp_dir == NULL || IS_ABSOLUTE_PATH (file->filename))
    return file->filename;

  return path_join (comp_dir, file->filename);
}