summaryrefslogtreecommitdiffstats
path: root/contrib/binutils/bfd/elf-strtab.c
blob: 7a993c252f518daf5c3cb2986f9267673113c962 (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
/* ELF strtab with GC and suffix merging support.
   Copyright 2001, 2002 Free Software Foundation, Inc.
   Written by Jakub Jelinek <jakub@redhat.com>.

   This file is part of BFD, the Binary File Descriptor library.

   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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "hashtab.h"
#include "libiberty.h"

/* An entry in the strtab hash table.  */

struct elf_strtab_hash_entry
{
  struct bfd_hash_entry root;
  /* Length of this entry.  */
  unsigned int len;
  unsigned int refcount;
  union {
    /* Index within the merged section.  */
    bfd_size_type index;
    /* Entry this is a suffix of (if len is 0).  */
    struct elf_strtab_hash_entry *suffix;
    struct elf_strtab_hash_entry *next;
  } u;
};

/* The strtab hash table.  */

struct elf_strtab_hash
{
  struct bfd_hash_table table;
  /* Next available index.  */
  bfd_size_type size;
  /* Number of array entries alloced.  */
  bfd_size_type alloced;
  /* Final strtab size.  */
  bfd_size_type sec_size;
  /* Array of pointers to strtab entries.  */
  struct elf_strtab_hash_entry **array;
};

static struct bfd_hash_entry *elf_strtab_hash_newfunc
  PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
static int cmplengthentry PARAMS ((const PTR, const PTR));
static int last4_eq PARAMS ((const PTR, const PTR));

/* Routine to create an entry in a section merge hashtab.  */

static struct bfd_hash_entry *
elf_strtab_hash_newfunc (entry, table, string)
     struct bfd_hash_entry *entry;
     struct bfd_hash_table *table;
     const char *string;
{
  struct elf_strtab_hash_entry *ret = (struct elf_strtab_hash_entry *) entry;

  /* Allocate the structure if it has not already been allocated by a
     subclass.  */
  if (ret == (struct elf_strtab_hash_entry *) NULL)
    ret = ((struct elf_strtab_hash_entry *)
	   bfd_hash_allocate (table, sizeof (struct elf_strtab_hash_entry)));
  if (ret == (struct elf_strtab_hash_entry *) NULL)
    return NULL;

  /* Call the allocation method of the superclass.  */
  ret = ((struct elf_strtab_hash_entry *)
	 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));

  if (ret)
    {
      /* Initialize the local fields.  */
      ret->u.index = -1;
      ret->refcount = 0;
      ret->len = 0;
    }

  return (struct bfd_hash_entry *)ret;
}

/* Create a new hash table.  */

struct elf_strtab_hash *
_bfd_elf_strtab_init ()
{
  struct elf_strtab_hash *table;
  bfd_size_type amt = sizeof (struct elf_strtab_hash);

  table = (struct elf_strtab_hash *) bfd_malloc (amt);
  if (table == NULL)
    return NULL;

  if (! bfd_hash_table_init (&table->table, elf_strtab_hash_newfunc))
    {
      free (table);
      return NULL;
    }

  table->sec_size = 0;
  table->size = 1;
  table->alloced = 64;
  amt = sizeof (struct elf_strtab_hasn_entry *);
  table->array = (struct elf_strtab_hash_entry **)
		 bfd_malloc (table->alloced * amt);
  if (table->array == NULL)
    {
      free (table);
      return NULL;
    }

  table->array[0] = NULL;

  return table;
}

/* Free a strtab.  */

void
_bfd_elf_strtab_free (tab)
     struct elf_strtab_hash *tab;
{
  bfd_hash_table_free (&tab->table);
  free (tab->array);
  free (tab);
}

/* Get the index of an entity in a hash table, adding it if it is not
   already present.  */

bfd_size_type
_bfd_elf_strtab_add (tab, str, copy)
     struct elf_strtab_hash *tab;
     const char *str;
     boolean copy;
{
  register struct elf_strtab_hash_entry *entry;

  /* We handle this specially, since we don't want to do refcounting
     on it.  */
  if (*str == '\0')
    return 0;

  BFD_ASSERT (tab->sec_size == 0);
  entry = (struct elf_strtab_hash_entry *)
	  bfd_hash_lookup (&tab->table, str, true, copy);

  if (entry == NULL)
    return (bfd_size_type) -1;

  entry->refcount++;
  if (entry->len == 0)
    {
      entry->len = strlen (str) + 1;
      if (tab->size == tab->alloced)
	{
	  bfd_size_type amt = sizeof (struct elf_strtab_hash_entry *);
	  tab->alloced *= 2;
	  tab->array = (struct elf_strtab_hash_entry **)
		       bfd_realloc (tab->array, tab->alloced * amt);
	  if (tab->array == NULL)
	    return (bfd_size_type) -1;
	}

      entry->u.index = tab->size++;
      tab->array[entry->u.index] = entry;
    }
  return entry->u.index;
}

void
_bfd_elf_strtab_addref (tab, idx)
     struct elf_strtab_hash *tab;
     bfd_size_type idx;
{
  if (idx == 0 || idx == (bfd_size_type) -1)
    return;
  BFD_ASSERT (tab->sec_size == 0);
  BFD_ASSERT (idx < tab->size);
  ++tab->array[idx]->refcount;
}

void
_bfd_elf_strtab_delref (tab, idx)
     struct elf_strtab_hash *tab;
     bfd_size_type idx;
{
  if (idx == 0 || idx == (bfd_size_type) -1)
    return;
  BFD_ASSERT (tab->sec_size == 0);
  BFD_ASSERT (idx < tab->size);
  BFD_ASSERT (tab->array[idx]->refcount > 0);
  --tab->array[idx]->refcount;
}

void
_bfd_elf_strtab_clear_all_refs (tab)
     struct elf_strtab_hash *tab;
{
  bfd_size_type idx;

  for (idx = 1; idx < tab->size; ++idx)
    tab->array[idx]->refcount = 0;
}

bfd_size_type
_bfd_elf_strtab_size (tab)
     struct elf_strtab_hash *tab;
{
  return tab->sec_size ? tab->sec_size : tab->size;
}

bfd_size_type
_bfd_elf_strtab_offset (tab, idx)
     struct elf_strtab_hash *tab;
     bfd_size_type idx;
{
  struct elf_strtab_hash_entry *entry;

  if (idx == 0)
    return 0;
  BFD_ASSERT (idx < tab->size);
  BFD_ASSERT (tab->sec_size);
  entry = tab->array[idx];
  BFD_ASSERT (entry->refcount > 0);
  entry->refcount--;
  return tab->array[idx]->u.index;
}

boolean
_bfd_elf_strtab_emit (abfd, tab)
     register bfd *abfd;
     struct elf_strtab_hash *tab;
{
  bfd_size_type off = 1, i;

  if (bfd_bwrite ("", 1, abfd) != 1)
    return false;

  for (i = 1; i < tab->size; ++i)
    {
      register const char *str;
      register size_t len;

      str = tab->array[i]->root.string;
      len = tab->array[i]->len;
      BFD_ASSERT (tab->array[i]->refcount == 0);
      if (len == 0)
	continue;

      if (bfd_bwrite ((PTR) str, (bfd_size_type) len, abfd) != len)
	return false;

      off += len;
    }

  BFD_ASSERT (off == tab->sec_size);
  return true;
}

/* Compare two elf_strtab_hash_entry structures.  This is called via qsort.  */

static int
cmplengthentry (a, b)
     const PTR a;
     const PTR b;
{
  struct elf_strtab_hash_entry * A = *(struct elf_strtab_hash_entry **) a;
  struct elf_strtab_hash_entry * B = *(struct elf_strtab_hash_entry **) b;

  if (A->len < B->len)
    return 1;
  else if (A->len > B->len)
    return -1;

  return memcmp (A->root.string, B->root.string, A->len);
}

static int
last4_eq (a, b)
     const PTR a;
     const PTR b;
{
  struct elf_strtab_hash_entry * A = (struct elf_strtab_hash_entry *) a;
  struct elf_strtab_hash_entry * B = (struct elf_strtab_hash_entry *) b;

  if (memcmp (A->root.string + A->len - 5, B->root.string + B->len - 5, 4)
      != 0)
    /* This was a hashtable collision.  */
    return 0;

  if (A->len <= B->len)
    /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
       not to be equal by the hash table.  */
    return 0;

  return memcmp (A->root.string + (A->len - B->len),
		 B->root.string, B->len - 5) == 0;
}

/* This function assigns final string table offsets for used strings,
   merging strings matching suffixes of longer strings if possible.  */

void
_bfd_elf_strtab_finalize (tab)
     struct elf_strtab_hash *tab;
{
  struct elf_strtab_hash_entry **array, **a, **end, *e;
  htab_t last4tab = NULL;
  bfd_size_type size, amt;
  struct elf_strtab_hash_entry *last[256], **last_ptr[256];

  /* GCC 2.91.66 (egcs-1.1.2) on i386 miscompiles this function when i is
     a 64-bit bfd_size_type: a 64-bit target or --enable-64-bit-bfd.
     Besides, indexing with a long long wouldn't give anything but extra
     cycles.  */
  size_t i;

  /* Now sort the strings by length, longest first.  */
  array = NULL;
  amt = tab->size * sizeof (struct elf_strtab_hash_entry *);
  array = (struct elf_strtab_hash_entry **) bfd_malloc (amt);
  if (array == NULL)
    goto alloc_failure;

  memset (last, 0, sizeof (last));
  for (i = 0; i < 256; ++i)
    last_ptr[i] = &last[i];
  for (i = 1, a = array; i < tab->size; ++i)
    if (tab->array[i]->refcount)
      *a++ = tab->array[i];
    else
      tab->array[i]->len = 0;

  size = a - array;

  qsort (array, size, sizeof (struct elf_strtab_hash_entry *), cmplengthentry);

  last4tab = htab_create_alloc (size * 4, NULL, last4_eq, NULL, calloc, free);
  if (last4tab == NULL)
    goto alloc_failure;

  /* Now insert the strings into hash tables (strings with last 4 characters
     and strings with last character equal), look for longer strings which
     we're suffix of.  */
  for (a = array, end = array + size; a < end; a++)
    {
      register hashval_t hash;
      unsigned int c;
      unsigned int j;
      const unsigned char *s;
      PTR *p;

      e = *a;
      if (e->len > 4)
	{
	  s = e->root.string + e->len - 1;
	  hash = 0;
	  for (j = 0; j < 4; j++)
	    {
	      c = *--s;
	      hash += c + (c << 17);
	      hash ^= hash >> 2;
	    }
	  p = htab_find_slot_with_hash (last4tab, e, hash, INSERT);
	  if (p == NULL)
	    goto alloc_failure;
	  if (*p)
	    {
	      struct elf_strtab_hash_entry *ent;

	      ent = (struct elf_strtab_hash_entry *) *p;
	      e->u.suffix = ent;
	      e->len = 0;
	      continue;
	    }
	  else
	    *p = (PTR) e;
	}
      else
	{
	  struct elf_strtab_hash_entry *tem;

	  c = e->root.string[e->len - 2] & 0xff;

	  for (tem = last[c]; tem; tem = tem->u.next)
	    if (tem->len > e->len
		&& memcmp (tem->root.string + (tem->len - e->len),
			   e->root.string, e->len - 1) == 0)
	      break;
	  if (tem)
	    {
	      e->u.suffix = tem;
	      e->len = 0;
	      continue;
	    }
	}

      c = e->root.string[e->len - 2] & 0xff;
      /* Put longest strings first.  */
      *last_ptr[c] = e;
      last_ptr[c] = &e->u.next;
      e->u.next = NULL;
    }

alloc_failure:
  if (array)
    free (array);
  if (last4tab)
    htab_delete (last4tab);

  /* Now assign positions to the strings we want to keep.  */
  size = 1;
  for (i = 1; i < tab->size; ++i)
    {
      e = tab->array[i];
      if (e->refcount && e->len)
	{
	  e->u.index = size;
	  size += e->len;
	}
    }

  tab->sec_size = size;

  /* And now adjust the rest.  */
  for (i = 1; i < tab->size; ++i)
    {
      e = tab->array[i];
      if (e->refcount && ! e->len)
	e->u.index = e->u.suffix->u.index
		     + (e->u.suffix->len - strlen (e->root.string) - 1);
    }
}
OpenPOWER on IntegriCloud