Commit | Line | Data |
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2b0f7ef9 | 1 | /* ELF strtab with GC and suffix merging support. |
b90efa5b | 2 | Copyright (C) 2001-2015 Free Software Foundation, Inc. |
2b0f7ef9 JJ |
3 | Written by Jakub Jelinek <jakub@redhat.com>. |
4 | ||
7217313c | 5 | This file is part of BFD, the Binary File Descriptor library. |
2b0f7ef9 | 6 | |
7217313c NC |
7 | This program is free software; you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
cd123cb7 | 9 | the Free Software Foundation; either version 3 of the License, or |
7217313c | 10 | (at your option) any later version. |
2b0f7ef9 | 11 | |
7217313c NC |
12 | This program is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
2b0f7ef9 | 16 | |
7217313c NC |
17 | You should have received a copy of the GNU General Public License |
18 | along with this program; if not, write to the Free Software | |
cd123cb7 NC |
19 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
20 | MA 02110-1301, USA. */ | |
2b0f7ef9 | 21 | |
2b0f7ef9 | 22 | #include "sysdep.h" |
3db64b00 | 23 | #include "bfd.h" |
2b0f7ef9 JJ |
24 | #include "libbfd.h" |
25 | #include "elf-bfd.h" | |
26 | #include "hashtab.h" | |
7217313c | 27 | #include "libiberty.h" |
2b0f7ef9 JJ |
28 | |
29 | /* An entry in the strtab hash table. */ | |
30 | ||
31 | struct elf_strtab_hash_entry | |
32 | { | |
33 | struct bfd_hash_entry root; | |
ddb2b442 AM |
34 | /* Length of this entry. This includes the zero terminator. */ |
35 | int len; | |
2b0f7ef9 JJ |
36 | unsigned int refcount; |
37 | union { | |
38 | /* Index within the merged section. */ | |
39 | bfd_size_type index; | |
ddb2b442 | 40 | /* Entry this is a suffix of (if len < 0). */ |
2b0f7ef9 JJ |
41 | struct elf_strtab_hash_entry *suffix; |
42 | } u; | |
43 | }; | |
44 | ||
45 | /* The strtab hash table. */ | |
46 | ||
47 | struct elf_strtab_hash | |
48 | { | |
49 | struct bfd_hash_table table; | |
50 | /* Next available index. */ | |
51 | bfd_size_type size; | |
52 | /* Number of array entries alloced. */ | |
53 | bfd_size_type alloced; | |
54 | /* Final strtab size. */ | |
55 | bfd_size_type sec_size; | |
56 | /* Array of pointers to strtab entries. */ | |
57 | struct elf_strtab_hash_entry **array; | |
58 | }; | |
59 | ||
2b0f7ef9 JJ |
60 | /* Routine to create an entry in a section merge hashtab. */ |
61 | ||
62 | static struct bfd_hash_entry * | |
c39a58e6 AM |
63 | elf_strtab_hash_newfunc (struct bfd_hash_entry *entry, |
64 | struct bfd_hash_table *table, | |
65 | const char *string) | |
2b0f7ef9 | 66 | { |
2b0f7ef9 JJ |
67 | /* Allocate the structure if it has not already been allocated by a |
68 | subclass. */ | |
c39a58e6 | 69 | if (entry == NULL) |
a50b1753 NC |
70 | entry = (struct bfd_hash_entry *) |
71 | bfd_hash_allocate (table, sizeof (struct elf_strtab_hash_entry)); | |
c39a58e6 | 72 | if (entry == NULL) |
2b0f7ef9 JJ |
73 | return NULL; |
74 | ||
75 | /* Call the allocation method of the superclass. */ | |
c39a58e6 | 76 | entry = bfd_hash_newfunc (entry, table, string); |
2b0f7ef9 | 77 | |
c39a58e6 | 78 | if (entry) |
2b0f7ef9 JJ |
79 | { |
80 | /* Initialize the local fields. */ | |
c39a58e6 AM |
81 | struct elf_strtab_hash_entry *ret; |
82 | ||
83 | ret = (struct elf_strtab_hash_entry *) entry; | |
2b0f7ef9 JJ |
84 | ret->u.index = -1; |
85 | ret->refcount = 0; | |
86 | ret->len = 0; | |
87 | } | |
88 | ||
c39a58e6 | 89 | return entry; |
2b0f7ef9 JJ |
90 | } |
91 | ||
92 | /* Create a new hash table. */ | |
93 | ||
94 | struct elf_strtab_hash * | |
c39a58e6 | 95 | _bfd_elf_strtab_init (void) |
2b0f7ef9 JJ |
96 | { |
97 | struct elf_strtab_hash *table; | |
98 | bfd_size_type amt = sizeof (struct elf_strtab_hash); | |
99 | ||
a50b1753 | 100 | table = (struct elf_strtab_hash *) bfd_malloc (amt); |
2b0f7ef9 JJ |
101 | if (table == NULL) |
102 | return NULL; | |
103 | ||
66eb6687 AM |
104 | if (!bfd_hash_table_init (&table->table, elf_strtab_hash_newfunc, |
105 | sizeof (struct elf_strtab_hash_entry))) | |
2b0f7ef9 JJ |
106 | { |
107 | free (table); | |
108 | return NULL; | |
109 | } | |
110 | ||
111 | table->sec_size = 0; | |
112 | table->size = 1; | |
113 | table->alloced = 64; | |
114 | amt = sizeof (struct elf_strtab_hasn_entry *); | |
a50b1753 NC |
115 | table->array = (struct elf_strtab_hash_entry **) |
116 | bfd_malloc (table->alloced * amt); | |
2b0f7ef9 JJ |
117 | if (table->array == NULL) |
118 | { | |
119 | free (table); | |
120 | return NULL; | |
121 | } | |
122 | ||
123 | table->array[0] = NULL; | |
124 | ||
125 | return table; | |
126 | } | |
127 | ||
128 | /* Free a strtab. */ | |
129 | ||
130 | void | |
c39a58e6 | 131 | _bfd_elf_strtab_free (struct elf_strtab_hash *tab) |
2b0f7ef9 JJ |
132 | { |
133 | bfd_hash_table_free (&tab->table); | |
134 | free (tab->array); | |
135 | free (tab); | |
136 | } | |
137 | ||
138 | /* Get the index of an entity in a hash table, adding it if it is not | |
139 | already present. */ | |
140 | ||
141 | bfd_size_type | |
c39a58e6 AM |
142 | _bfd_elf_strtab_add (struct elf_strtab_hash *tab, |
143 | const char *str, | |
144 | bfd_boolean copy) | |
2b0f7ef9 JJ |
145 | { |
146 | register struct elf_strtab_hash_entry *entry; | |
147 | ||
148 | /* We handle this specially, since we don't want to do refcounting | |
149 | on it. */ | |
150 | if (*str == '\0') | |
151 | return 0; | |
152 | ||
153 | BFD_ASSERT (tab->sec_size == 0); | |
154 | entry = (struct elf_strtab_hash_entry *) | |
b34976b6 | 155 | bfd_hash_lookup (&tab->table, str, TRUE, copy); |
2b0f7ef9 JJ |
156 | |
157 | if (entry == NULL) | |
158 | return (bfd_size_type) -1; | |
159 | ||
160 | entry->refcount++; | |
161 | if (entry->len == 0) | |
162 | { | |
163 | entry->len = strlen (str) + 1; | |
ddb2b442 AM |
164 | /* 2G strings lose. */ |
165 | BFD_ASSERT (entry->len > 0); | |
2b0f7ef9 JJ |
166 | if (tab->size == tab->alloced) |
167 | { | |
168 | bfd_size_type amt = sizeof (struct elf_strtab_hash_entry *); | |
169 | tab->alloced *= 2; | |
a50b1753 NC |
170 | tab->array = (struct elf_strtab_hash_entry **) |
171 | bfd_realloc_or_free (tab->array, tab->alloced * amt); | |
2b0f7ef9 JJ |
172 | if (tab->array == NULL) |
173 | return (bfd_size_type) -1; | |
174 | } | |
175 | ||
176 | entry->u.index = tab->size++; | |
177 | tab->array[entry->u.index] = entry; | |
178 | } | |
179 | return entry->u.index; | |
180 | } | |
181 | ||
182 | void | |
c39a58e6 | 183 | _bfd_elf_strtab_addref (struct elf_strtab_hash *tab, bfd_size_type idx) |
2b0f7ef9 JJ |
184 | { |
185 | if (idx == 0 || idx == (bfd_size_type) -1) | |
186 | return; | |
187 | BFD_ASSERT (tab->sec_size == 0); | |
188 | BFD_ASSERT (idx < tab->size); | |
189 | ++tab->array[idx]->refcount; | |
190 | } | |
191 | ||
192 | void | |
c39a58e6 | 193 | _bfd_elf_strtab_delref (struct elf_strtab_hash *tab, bfd_size_type idx) |
2b0f7ef9 JJ |
194 | { |
195 | if (idx == 0 || idx == (bfd_size_type) -1) | |
196 | return; | |
197 | BFD_ASSERT (tab->sec_size == 0); | |
198 | BFD_ASSERT (idx < tab->size); | |
199 | BFD_ASSERT (tab->array[idx]->refcount > 0); | |
200 | --tab->array[idx]->refcount; | |
201 | } | |
202 | ||
02be4619 AM |
203 | unsigned int |
204 | _bfd_elf_strtab_refcount (struct elf_strtab_hash *tab, bfd_size_type idx) | |
205 | { | |
206 | return tab->array[idx]->refcount; | |
207 | } | |
208 | ||
2b0f7ef9 | 209 | void |
d45f8bda | 210 | _bfd_elf_strtab_clear_all_refs (struct elf_strtab_hash *tab) |
2b0f7ef9 | 211 | { |
d45f8bda AM |
212 | bfd_size_type idx; |
213 | ||
214 | for (idx = 1; idx < tab->size; idx++) | |
215 | tab->array[idx]->refcount = 0; | |
216 | } | |
217 | ||
218 | /* Downsizes strtab. Entries from IDX up to the current size are | |
219 | removed from the array. */ | |
220 | void | |
221 | _bfd_elf_strtab_restore_size (struct elf_strtab_hash *tab, bfd_size_type idx) | |
222 | { | |
223 | bfd_size_type curr_size = tab->size; | |
224 | ||
225 | BFD_ASSERT (tab->sec_size == 0); | |
226 | BFD_ASSERT (idx <= curr_size); | |
227 | tab->size = idx; | |
228 | for (; idx < curr_size; ++idx) | |
229 | { | |
230 | /* We don't remove entries from the hash table, just set their | |
231 | REFCOUNT to zero. Setting LEN zero will result in the size | |
232 | growing if the entry is added again. See _bfd_elf_strtab_add. */ | |
233 | tab->array[idx]->refcount = 0; | |
234 | tab->array[idx]->len = 0; | |
235 | } | |
2b0f7ef9 JJ |
236 | } |
237 | ||
238 | bfd_size_type | |
c39a58e6 | 239 | _bfd_elf_strtab_size (struct elf_strtab_hash *tab) |
2b0f7ef9 JJ |
240 | { |
241 | return tab->sec_size ? tab->sec_size : tab->size; | |
242 | } | |
243 | ||
244 | bfd_size_type | |
c39a58e6 | 245 | _bfd_elf_strtab_offset (struct elf_strtab_hash *tab, bfd_size_type idx) |
2b0f7ef9 JJ |
246 | { |
247 | struct elf_strtab_hash_entry *entry; | |
248 | ||
249 | if (idx == 0) | |
250 | return 0; | |
251 | BFD_ASSERT (idx < tab->size); | |
252 | BFD_ASSERT (tab->sec_size); | |
253 | entry = tab->array[idx]; | |
254 | BFD_ASSERT (entry->refcount > 0); | |
255 | entry->refcount--; | |
256 | return tab->array[idx]->u.index; | |
257 | } | |
258 | ||
b34976b6 | 259 | bfd_boolean |
c39a58e6 | 260 | _bfd_elf_strtab_emit (register bfd *abfd, struct elf_strtab_hash *tab) |
2b0f7ef9 JJ |
261 | { |
262 | bfd_size_type off = 1, i; | |
263 | ||
264 | if (bfd_bwrite ("", 1, abfd) != 1) | |
b34976b6 | 265 | return FALSE; |
2b0f7ef9 JJ |
266 | |
267 | for (i = 1; i < tab->size; ++i) | |
268 | { | |
269 | register const char *str; | |
ddb2b442 | 270 | register unsigned int len; |
2b0f7ef9 | 271 | |
2b0f7ef9 | 272 | BFD_ASSERT (tab->array[i]->refcount == 0); |
ddb2b442 AM |
273 | len = tab->array[i]->len; |
274 | if ((int) len < 0) | |
2b0f7ef9 JJ |
275 | continue; |
276 | ||
ddb2b442 | 277 | str = tab->array[i]->root.string; |
c39a58e6 | 278 | if (bfd_bwrite (str, len, abfd) != len) |
b34976b6 | 279 | return FALSE; |
2b0f7ef9 JJ |
280 | |
281 | off += len; | |
282 | } | |
283 | ||
284 | BFD_ASSERT (off == tab->sec_size); | |
b34976b6 | 285 | return TRUE; |
2b0f7ef9 JJ |
286 | } |
287 | ||
ddb2b442 | 288 | /* Compare two elf_strtab_hash_entry structures. Called via qsort. */ |
2b0f7ef9 JJ |
289 | |
290 | static int | |
ddb2b442 | 291 | strrevcmp (const void *a, const void *b) |
2b0f7ef9 | 292 | { |
c39a58e6 AM |
293 | struct elf_strtab_hash_entry *A = *(struct elf_strtab_hash_entry **) a; |
294 | struct elf_strtab_hash_entry *B = *(struct elf_strtab_hash_entry **) b; | |
ddb2b442 AM |
295 | unsigned int lenA = A->len; |
296 | unsigned int lenB = B->len; | |
f075ee0c AM |
297 | const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1; |
298 | const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1; | |
ddb2b442 | 299 | int l = lenA < lenB ? lenA : lenB; |
2b0f7ef9 | 300 | |
ddb2b442 AM |
301 | while (l) |
302 | { | |
303 | if (*s != *t) | |
304 | return (int) *s - (int) *t; | |
305 | s--; | |
306 | t--; | |
307 | l--; | |
308 | } | |
309 | return lenA - lenB; | |
2b0f7ef9 JJ |
310 | } |
311 | ||
ddb2b442 AM |
312 | static inline int |
313 | is_suffix (const struct elf_strtab_hash_entry *A, | |
314 | const struct elf_strtab_hash_entry *B) | |
2b0f7ef9 | 315 | { |
2b0f7ef9 JJ |
316 | if (A->len <= B->len) |
317 | /* B cannot be a suffix of A unless A is equal to B, which is guaranteed | |
318 | not to be equal by the hash table. */ | |
319 | return 0; | |
320 | ||
321 | return memcmp (A->root.string + (A->len - B->len), | |
ddb2b442 | 322 | B->root.string, B->len - 1) == 0; |
2b0f7ef9 JJ |
323 | } |
324 | ||
2b0f7ef9 JJ |
325 | /* This function assigns final string table offsets for used strings, |
326 | merging strings matching suffixes of longer strings if possible. */ | |
327 | ||
328 | void | |
c39a58e6 | 329 | _bfd_elf_strtab_finalize (struct elf_strtab_hash *tab) |
2b0f7ef9 | 330 | { |
ddb2b442 | 331 | struct elf_strtab_hash_entry **array, **a, *e; |
b959dc73 HPN |
332 | bfd_size_type size, amt; |
333 | ||
334 | /* GCC 2.91.66 (egcs-1.1.2) on i386 miscompiles this function when i is | |
335 | a 64-bit bfd_size_type: a 64-bit target or --enable-64-bit-bfd. | |
336 | Besides, indexing with a long long wouldn't give anything but extra | |
337 | cycles. */ | |
338 | size_t i; | |
2b0f7ef9 | 339 | |
ddb2b442 | 340 | /* Sort the strings by suffix and length. */ |
2b0f7ef9 | 341 | amt = tab->size * sizeof (struct elf_strtab_hash_entry *); |
a50b1753 | 342 | array = (struct elf_strtab_hash_entry **) bfd_malloc (amt); |
2b0f7ef9 JJ |
343 | if (array == NULL) |
344 | goto alloc_failure; | |
345 | ||
346 | for (i = 1, a = array; i < tab->size; ++i) | |
ddb2b442 AM |
347 | { |
348 | e = tab->array[i]; | |
349 | if (e->refcount) | |
350 | { | |
351 | *a++ = e; | |
352 | /* Adjust the length to not include the zero terminator. */ | |
353 | e->len -= 1; | |
354 | } | |
355 | else | |
356 | e->len = 0; | |
357 | } | |
2b0f7ef9 JJ |
358 | |
359 | size = a - array; | |
ddb2b442 AM |
360 | if (size != 0) |
361 | { | |
362 | qsort (array, size, sizeof (struct elf_strtab_hash_entry *), strrevcmp); | |
2b0f7ef9 | 363 | |
ddb2b442 AM |
364 | /* Loop over the sorted array and merge suffixes. Start from the |
365 | end because we want eg. | |
2b0f7ef9 | 366 | |
ddb2b442 AM |
367 | s1 -> "d" |
368 | s2 -> "bcd" | |
369 | s3 -> "abcd" | |
2b0f7ef9 | 370 | |
ddb2b442 | 371 | to end up as |
2b0f7ef9 | 372 | |
ddb2b442 AM |
373 | s3 -> "abcd" |
374 | s2 _____^ | |
375 | s1 _______^ | |
2b0f7ef9 | 376 | |
ddb2b442 AM |
377 | ie. we don't want s1 pointing into the old s2. */ |
378 | e = *--a; | |
379 | e->len += 1; | |
380 | while (--a >= array) | |
381 | { | |
382 | struct elf_strtab_hash_entry *cmp = *a; | |
53c3f2be | 383 | |
ddb2b442 AM |
384 | cmp->len += 1; |
385 | if (is_suffix (e, cmp)) | |
53c3f2be | 386 | { |
ddb2b442 AM |
387 | cmp->u.suffix = e; |
388 | cmp->len = -cmp->len; | |
53c3f2be | 389 | } |
ddb2b442 AM |
390 | else |
391 | e = cmp; | |
2b0f7ef9 | 392 | } |
2b0f7ef9 JJ |
393 | } |
394 | ||
395 | alloc_failure: | |
396 | if (array) | |
397 | free (array); | |
2b0f7ef9 | 398 | |
ddb2b442 | 399 | /* Assign positions to the strings we want to keep. */ |
2b0f7ef9 JJ |
400 | size = 1; |
401 | for (i = 1; i < tab->size; ++i) | |
402 | { | |
403 | e = tab->array[i]; | |
ddb2b442 | 404 | if (e->refcount && e->len > 0) |
2b0f7ef9 JJ |
405 | { |
406 | e->u.index = size; | |
407 | size += e->len; | |
408 | } | |
409 | } | |
410 | ||
411 | tab->sec_size = size; | |
412 | ||
ddb2b442 | 413 | /* Adjust the rest. */ |
2b0f7ef9 JJ |
414 | for (i = 1; i < tab->size; ++i) |
415 | { | |
416 | e = tab->array[i]; | |
ddb2b442 AM |
417 | if (e->refcount && e->len < 0) |
418 | e->u.index = e->u.suffix->u.index + (e->u.suffix->len + e->len); | |
2b0f7ef9 JJ |
419 | } |
420 | } |