1 /* ELF strtab with GC and suffix merging support.
2 Copyright (C) 2001-2014 Free Software Foundation, Inc.
3 Written by Jakub Jelinek <jakub@redhat.com>.
5 This file is part of BFD, the Binary File Descriptor library.
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
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
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.
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
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
27 #include "libiberty.h"
29 /* An entry in the strtab hash table. */
31 struct elf_strtab_hash_entry
33 struct bfd_hash_entry root
;
34 /* Length of this entry. This includes the zero terminator. */
36 unsigned int refcount
;
38 /* Index within the merged section. */
40 /* Entry this is a suffix of (if len < 0). */
41 struct elf_strtab_hash_entry
*suffix
;
45 /* The strtab hash table. */
47 struct elf_strtab_hash
49 struct bfd_hash_table table
;
50 /* Next available index. */
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
;
60 /* Routine to create an entry in a section merge hashtab. */
62 static struct bfd_hash_entry
*
63 elf_strtab_hash_newfunc (struct bfd_hash_entry
*entry
,
64 struct bfd_hash_table
*table
,
67 /* Allocate the structure if it has not already been allocated by a
70 entry
= (struct bfd_hash_entry
*)
71 bfd_hash_allocate (table
, sizeof (struct elf_strtab_hash_entry
));
75 /* Call the allocation method of the superclass. */
76 entry
= bfd_hash_newfunc (entry
, table
, string
);
80 /* Initialize the local fields. */
81 struct elf_strtab_hash_entry
*ret
;
83 ret
= (struct elf_strtab_hash_entry
*) entry
;
92 /* Create a new hash table. */
94 struct elf_strtab_hash
*
95 _bfd_elf_strtab_init (void)
97 struct elf_strtab_hash
*table
;
98 bfd_size_type amt
= sizeof (struct elf_strtab_hash
);
100 table
= (struct elf_strtab_hash
*) bfd_malloc (amt
);
104 if (!bfd_hash_table_init (&table
->table
, elf_strtab_hash_newfunc
,
105 sizeof (struct elf_strtab_hash_entry
)))
114 amt
= sizeof (struct elf_strtab_hasn_entry
*);
115 table
->array
= (struct elf_strtab_hash_entry
**)
116 bfd_malloc (table
->alloced
* amt
);
117 if (table
->array
== NULL
)
123 table
->array
[0] = NULL
;
131 _bfd_elf_strtab_free (struct elf_strtab_hash
*tab
)
133 bfd_hash_table_free (&tab
->table
);
138 /* Get the index of an entity in a hash table, adding it if it is not
142 _bfd_elf_strtab_add (struct elf_strtab_hash
*tab
,
146 register struct elf_strtab_hash_entry
*entry
;
148 /* We handle this specially, since we don't want to do refcounting
153 BFD_ASSERT (tab
->sec_size
== 0);
154 entry
= (struct elf_strtab_hash_entry
*)
155 bfd_hash_lookup (&tab
->table
, str
, TRUE
, copy
);
158 return (bfd_size_type
) -1;
163 entry
->len
= strlen (str
) + 1;
164 /* 2G strings lose. */
165 BFD_ASSERT (entry
->len
> 0);
166 if (tab
->size
== tab
->alloced
)
168 bfd_size_type amt
= sizeof (struct elf_strtab_hash_entry
*);
170 tab
->array
= (struct elf_strtab_hash_entry
**)
171 bfd_realloc_or_free (tab
->array
, tab
->alloced
* amt
);
172 if (tab
->array
== NULL
)
173 return (bfd_size_type
) -1;
176 entry
->u
.index
= tab
->size
++;
177 tab
->array
[entry
->u
.index
] = entry
;
179 return entry
->u
.index
;
183 _bfd_elf_strtab_addref (struct elf_strtab_hash
*tab
, bfd_size_type idx
)
185 if (idx
== 0 || idx
== (bfd_size_type
) -1)
187 BFD_ASSERT (tab
->sec_size
== 0);
188 BFD_ASSERT (idx
< tab
->size
);
189 ++tab
->array
[idx
]->refcount
;
193 _bfd_elf_strtab_delref (struct elf_strtab_hash
*tab
, bfd_size_type idx
)
195 if (idx
== 0 || idx
== (bfd_size_type
) -1)
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
;
204 _bfd_elf_strtab_refcount (struct elf_strtab_hash
*tab
, bfd_size_type idx
)
206 return tab
->array
[idx
]->refcount
;
210 _bfd_elf_strtab_clear_all_refs (struct elf_strtab_hash
*tab
)
214 for (idx
= 1; idx
< tab
->size
; idx
++)
215 tab
->array
[idx
]->refcount
= 0;
218 /* Downsizes strtab. Entries from IDX up to the current size are
219 removed from the array. */
221 _bfd_elf_strtab_restore_size (struct elf_strtab_hash
*tab
, bfd_size_type idx
)
223 bfd_size_type curr_size
= tab
->size
;
225 BFD_ASSERT (tab
->sec_size
== 0);
226 BFD_ASSERT (idx
<= curr_size
);
228 for (; idx
< curr_size
; ++idx
)
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;
239 _bfd_elf_strtab_size (struct elf_strtab_hash
*tab
)
241 return tab
->sec_size
? tab
->sec_size
: tab
->size
;
245 _bfd_elf_strtab_offset (struct elf_strtab_hash
*tab
, bfd_size_type idx
)
247 struct elf_strtab_hash_entry
*entry
;
251 BFD_ASSERT (idx
< tab
->size
);
252 BFD_ASSERT (tab
->sec_size
);
253 entry
= tab
->array
[idx
];
254 BFD_ASSERT (entry
->refcount
> 0);
256 return tab
->array
[idx
]->u
.index
;
260 _bfd_elf_strtab_emit (register bfd
*abfd
, struct elf_strtab_hash
*tab
)
262 bfd_size_type off
= 1, i
;
264 if (bfd_bwrite ("", 1, abfd
) != 1)
267 for (i
= 1; i
< tab
->size
; ++i
)
269 register const char *str
;
270 register unsigned int len
;
272 BFD_ASSERT (tab
->array
[i
]->refcount
== 0);
273 len
= tab
->array
[i
]->len
;
277 str
= tab
->array
[i
]->root
.string
;
278 if (bfd_bwrite (str
, len
, abfd
) != len
)
284 BFD_ASSERT (off
== tab
->sec_size
);
288 /* Compare two elf_strtab_hash_entry structures. Called via qsort. */
291 strrevcmp (const void *a
, const void *b
)
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
;
295 unsigned int lenA
= A
->len
;
296 unsigned int lenB
= B
->len
;
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;
299 int l
= lenA
< lenB
? lenA
: lenB
;
304 return (int) *s
- (int) *t
;
313 is_suffix (const struct elf_strtab_hash_entry
*A
,
314 const struct elf_strtab_hash_entry
*B
)
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. */
321 return memcmp (A
->root
.string
+ (A
->len
- B
->len
),
322 B
->root
.string
, B
->len
- 1) == 0;
325 /* This function assigns final string table offsets for used strings,
326 merging strings matching suffixes of longer strings if possible. */
329 _bfd_elf_strtab_finalize (struct elf_strtab_hash
*tab
)
331 struct elf_strtab_hash_entry
**array
, **a
, *e
;
332 bfd_size_type size
, amt
;
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
340 /* Sort the strings by suffix and length. */
341 amt
= tab
->size
* sizeof (struct elf_strtab_hash_entry
*);
342 array
= (struct elf_strtab_hash_entry
**) bfd_malloc (amt
);
346 for (i
= 1, a
= array
; i
< tab
->size
; ++i
)
352 /* Adjust the length to not include the zero terminator. */
362 qsort (array
, size
, sizeof (struct elf_strtab_hash_entry
*), strrevcmp
);
364 /* Loop over the sorted array and merge suffixes. Start from the
365 end because we want eg.
377 ie. we don't want s1 pointing into the old s2. */
382 struct elf_strtab_hash_entry
*cmp
= *a
;
385 if (is_suffix (e
, cmp
))
388 cmp
->len
= -cmp
->len
;
399 /* Assign positions to the strings we want to keep. */
401 for (i
= 1; i
< tab
->size
; ++i
)
404 if (e
->refcount
&& e
->len
> 0)
411 tab
->sec_size
= size
;
413 /* Adjust the rest. */
414 for (i
= 1; i
< tab
->size
; ++i
)
417 if (e
->refcount
&& e
->len
< 0)
418 e
->u
.index
= e
->u
.suffix
->u
.index
+ (e
->u
.suffix
->len
+ e
->len
);
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