Commit | Line | Data |
---|---|---|
65765700 | 1 | /* .eh_frame section optimization. |
68bfbfcc | 2 | Copyright 2001, 2002, 2003 Free Software Foundation, Inc. |
65765700 JJ |
3 | Written by Jakub Jelinek <jakub@redhat.com>. |
4 | ||
5ed6aba4 | 5 | This file is part of BFD, the Binary File Descriptor library. |
65765700 | 6 | |
5ed6aba4 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 | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
65765700 | 11 | |
5ed6aba4 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. | |
65765700 | 16 | |
5ed6aba4 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 | |
19 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
65765700 JJ |
20 | |
21 | #include "bfd.h" | |
22 | #include "sysdep.h" | |
23 | #include "libbfd.h" | |
24 | #include "elf-bfd.h" | |
25 | #include "elf/dwarf2.h" | |
26 | ||
27 | #define EH_FRAME_HDR_SIZE 8 | |
28 | ||
65765700 JJ |
29 | /* Helper function for reading uleb128 encoded data. */ |
30 | ||
31 | static bfd_vma | |
c39a58e6 AM |
32 | read_unsigned_leb128 (bfd *abfd ATTRIBUTE_UNUSED, |
33 | char *buf, | |
34 | unsigned int *bytes_read_ptr) | |
65765700 | 35 | { |
c39a58e6 AM |
36 | bfd_vma result; |
37 | unsigned int num_read; | |
38 | int shift; | |
65765700 JJ |
39 | unsigned char byte; |
40 | ||
c39a58e6 AM |
41 | result = 0; |
42 | shift = 0; | |
65765700 JJ |
43 | num_read = 0; |
44 | do | |
45 | { | |
46 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
c39a58e6 AM |
47 | buf++; |
48 | num_read++; | |
65765700 JJ |
49 | result |= (((bfd_vma) byte & 0x7f) << shift); |
50 | shift += 7; | |
51 | } | |
52 | while (byte & 0x80); | |
c39a58e6 | 53 | *bytes_read_ptr = num_read; |
65765700 JJ |
54 | return result; |
55 | } | |
56 | ||
57 | /* Helper function for reading sleb128 encoded data. */ | |
58 | ||
59 | static bfd_signed_vma | |
c39a58e6 AM |
60 | read_signed_leb128 (bfd *abfd ATTRIBUTE_UNUSED, |
61 | char *buf, | |
62 | unsigned int * bytes_read_ptr) | |
65765700 | 63 | { |
c39a58e6 AM |
64 | bfd_vma result; |
65 | int shift; | |
66 | int num_read; | |
65765700 JJ |
67 | unsigned char byte; |
68 | ||
69 | result = 0; | |
70 | shift = 0; | |
71 | num_read = 0; | |
72 | do | |
73 | { | |
74 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
75 | buf ++; | |
76 | num_read ++; | |
77 | result |= (((bfd_vma) byte & 0x7f) << shift); | |
78 | shift += 7; | |
79 | } | |
80 | while (byte & 0x80); | |
81 | if (byte & 0x40) | |
82 | result |= (((bfd_vma) -1) << (shift - 7)) << 7; | |
c39a58e6 | 83 | *bytes_read_ptr = num_read; |
65765700 JJ |
84 | return result; |
85 | } | |
86 | ||
87 | #define read_uleb128(VAR, BUF) \ | |
88 | do \ | |
89 | { \ | |
90 | (VAR) = read_unsigned_leb128 (abfd, buf, &leb128_tmp); \ | |
91 | (BUF) += leb128_tmp; \ | |
92 | } \ | |
93 | while (0) | |
94 | ||
95 | #define read_sleb128(VAR, BUF) \ | |
96 | do \ | |
97 | { \ | |
98 | (VAR) = read_signed_leb128 (abfd, buf, &leb128_tmp); \ | |
99 | (BUF) += leb128_tmp; \ | |
100 | } \ | |
101 | while (0) | |
102 | ||
103 | /* Return 0 if either encoding is variable width, or not yet known to bfd. */ | |
104 | ||
105 | static | |
c39a58e6 | 106 | int get_DW_EH_PE_width (int encoding, int ptr_size) |
65765700 JJ |
107 | { |
108 | /* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame | |
109 | was added to bfd. */ | |
110 | if ((encoding & 0x60) == 0x60) | |
111 | return 0; | |
112 | ||
113 | switch (encoding & 7) | |
114 | { | |
115 | case DW_EH_PE_udata2: return 2; | |
116 | case DW_EH_PE_udata4: return 4; | |
117 | case DW_EH_PE_udata8: return 8; | |
118 | case DW_EH_PE_absptr: return ptr_size; | |
119 | default: | |
120 | break; | |
121 | } | |
122 | ||
123 | return 0; | |
124 | } | |
125 | ||
84f97cb6 AS |
126 | #define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0) |
127 | ||
9e2a4898 JJ |
128 | /* Read a width sized value from memory. */ |
129 | ||
130 | static bfd_vma | |
c39a58e6 | 131 | read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed) |
9e2a4898 JJ |
132 | { |
133 | bfd_vma value; | |
134 | ||
135 | switch (width) | |
136 | { | |
84f97cb6 AS |
137 | case 2: |
138 | if (is_signed) | |
139 | value = bfd_get_signed_16 (abfd, buf); | |
140 | else | |
141 | value = bfd_get_16 (abfd, buf); | |
142 | break; | |
143 | case 4: | |
144 | if (is_signed) | |
145 | value = bfd_get_signed_32 (abfd, buf); | |
146 | else | |
147 | value = bfd_get_32 (abfd, buf); | |
148 | break; | |
149 | case 8: | |
150 | if (is_signed) | |
151 | value = bfd_get_signed_64 (abfd, buf); | |
152 | else | |
153 | value = bfd_get_64 (abfd, buf); | |
154 | break; | |
155 | default: | |
156 | BFD_FAIL (); | |
157 | return 0; | |
9e2a4898 JJ |
158 | } |
159 | ||
160 | return value; | |
161 | } | |
b34976b6 | 162 | |
9e2a4898 JJ |
163 | /* Store a width sized value to memory. */ |
164 | ||
165 | static void | |
c39a58e6 | 166 | write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width) |
9e2a4898 JJ |
167 | { |
168 | switch (width) | |
169 | { | |
170 | case 2: bfd_put_16 (abfd, value, buf); break; | |
171 | case 4: bfd_put_32 (abfd, value, buf); break; | |
172 | case 8: bfd_put_64 (abfd, value, buf); break; | |
173 | default: BFD_FAIL (); | |
174 | } | |
175 | } | |
176 | ||
65765700 JJ |
177 | /* Return zero if C1 and C2 CIEs can be merged. */ |
178 | ||
179 | static | |
c39a58e6 | 180 | int cie_compare (struct cie *c1, struct cie *c2) |
65765700 JJ |
181 | { |
182 | if (c1->hdr.length == c2->hdr.length | |
183 | && c1->version == c2->version | |
184 | && strcmp (c1->augmentation, c2->augmentation) == 0 | |
185 | && strcmp (c1->augmentation, "eh") != 0 | |
186 | && c1->code_align == c2->code_align | |
187 | && c1->data_align == c2->data_align | |
188 | && c1->ra_column == c2->ra_column | |
189 | && c1->augmentation_size == c2->augmentation_size | |
190 | && c1->personality == c2->personality | |
191 | && c1->per_encoding == c2->per_encoding | |
192 | && c1->lsda_encoding == c2->lsda_encoding | |
193 | && c1->fde_encoding == c2->fde_encoding | |
c39a58e6 | 194 | && c1->initial_insn_length == c2->initial_insn_length |
65765700 JJ |
195 | && memcmp (c1->initial_instructions, |
196 | c2->initial_instructions, | |
197 | c1->initial_insn_length) == 0) | |
198 | return 0; | |
199 | ||
200 | return 1; | |
201 | } | |
202 | ||
203 | /* This function is called for each input file before the .eh_frame | |
204 | section is relocated. It discards duplicate CIEs and FDEs for discarded | |
b34976b6 | 205 | functions. The function returns TRUE iff any entries have been |
65765700 JJ |
206 | deleted. */ |
207 | ||
b34976b6 | 208 | bfd_boolean |
c39a58e6 AM |
209 | _bfd_elf_discard_section_eh_frame |
210 | (bfd *abfd, struct bfd_link_info *info, asection *sec, | |
211 | bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *), | |
212 | struct elf_reloc_cookie *cookie) | |
65765700 JJ |
213 | { |
214 | bfd_byte *ehbuf = NULL, *buf; | |
215 | bfd_byte *last_cie, *last_fde; | |
216 | struct cie_header hdr; | |
217 | struct cie cie; | |
126495ed | 218 | struct elf_link_hash_table *htab; |
65765700 | 219 | struct eh_frame_hdr_info *hdr_info; |
68f69152 | 220 | struct eh_frame_sec_info *sec_info = NULL; |
65765700 | 221 | unsigned int leb128_tmp; |
9e2a4898 JJ |
222 | unsigned int cie_usage_count, last_cie_ndx, i, offset; |
223 | unsigned int make_relative, make_lsda_relative; | |
65765700 JJ |
224 | bfd_size_type new_size; |
225 | unsigned int ptr_size; | |
226 | ||
227 | if (sec->_raw_size == 0) | |
228 | { | |
229 | /* This file does not contain .eh_frame information. */ | |
b34976b6 | 230 | return FALSE; |
65765700 JJ |
231 | } |
232 | ||
233 | if ((sec->output_section != NULL | |
234 | && bfd_is_abs_section (sec->output_section))) | |
235 | { | |
236 | /* At least one of the sections is being discarded from the | |
237 | link, so we should just ignore them. */ | |
b34976b6 | 238 | return FALSE; |
65765700 JJ |
239 | } |
240 | ||
126495ed AM |
241 | htab = elf_hash_table (info); |
242 | hdr_info = &htab->eh_info; | |
68f69152 | 243 | |
65765700 JJ |
244 | /* Read the frame unwind information from abfd. */ |
245 | ||
c39a58e6 | 246 | ehbuf = bfd_malloc (sec->_raw_size); |
68f69152 JJ |
247 | if (ehbuf == NULL) |
248 | goto free_no_table; | |
249 | ||
c39a58e6 | 250 | if (! bfd_get_section_contents (abfd, sec, ehbuf, 0, sec->_raw_size)) |
68f69152 | 251 | goto free_no_table; |
65765700 JJ |
252 | |
253 | if (sec->_raw_size >= 4 | |
254 | && bfd_get_32 (abfd, ehbuf) == 0 | |
255 | && cookie->rel == cookie->relend) | |
256 | { | |
257 | /* Empty .eh_frame section. */ | |
258 | free (ehbuf); | |
b34976b6 | 259 | return FALSE; |
65765700 JJ |
260 | } |
261 | ||
65765700 JJ |
262 | /* If .eh_frame section size doesn't fit into int, we cannot handle |
263 | it (it would need to use 64-bit .eh_frame format anyway). */ | |
264 | if (sec->_raw_size != (unsigned int) sec->_raw_size) | |
68f69152 | 265 | goto free_no_table; |
65765700 JJ |
266 | |
267 | ptr_size = (elf_elfheader (abfd)->e_ident[EI_CLASS] | |
268 | == ELFCLASS64) ? 8 : 4; | |
269 | buf = ehbuf; | |
270 | last_cie = NULL; | |
271 | last_cie_ndx = 0; | |
272 | memset (&cie, 0, sizeof (cie)); | |
273 | cie_usage_count = 0; | |
274 | new_size = sec->_raw_size; | |
275 | make_relative = hdr_info->last_cie.make_relative; | |
9e2a4898 | 276 | make_lsda_relative = hdr_info->last_cie.make_lsda_relative; |
65765700 JJ |
277 | sec_info = bfd_zmalloc (sizeof (struct eh_frame_sec_info) |
278 | + 99 * sizeof (struct eh_cie_fde)); | |
279 | if (sec_info == NULL) | |
280 | goto free_no_table; | |
281 | sec_info->alloced = 100; | |
282 | ||
283 | #define ENSURE_NO_RELOCS(buf) \ | |
284 | if (cookie->rel < cookie->relend \ | |
285 | && (cookie->rel->r_offset \ | |
73722af0 AM |
286 | < (bfd_size_type) ((buf) - ehbuf)) \ |
287 | && cookie->rel->r_info != 0) \ | |
65765700 JJ |
288 | goto free_no_table |
289 | ||
290 | #define SKIP_RELOCS(buf) \ | |
291 | while (cookie->rel < cookie->relend \ | |
292 | && (cookie->rel->r_offset \ | |
293 | < (bfd_size_type) ((buf) - ehbuf))) \ | |
294 | cookie->rel++ | |
295 | ||
296 | #define GET_RELOC(buf) \ | |
297 | ((cookie->rel < cookie->relend \ | |
298 | && (cookie->rel->r_offset \ | |
299 | == (bfd_size_type) ((buf) - ehbuf))) \ | |
300 | ? cookie->rel : NULL) | |
301 | ||
302 | for (;;) | |
303 | { | |
304 | unsigned char *aug; | |
305 | ||
306 | if (sec_info->count == sec_info->alloced) | |
307 | { | |
308 | sec_info = bfd_realloc (sec_info, | |
309 | sizeof (struct eh_frame_sec_info) | |
310 | + (sec_info->alloced + 99) | |
311 | * sizeof (struct eh_cie_fde)); | |
312 | if (sec_info == NULL) | |
313 | goto free_no_table; | |
314 | ||
315 | memset (&sec_info->entry[sec_info->alloced], 0, | |
316 | 100 * sizeof (struct eh_cie_fde)); | |
317 | sec_info->alloced += 100; | |
318 | } | |
319 | ||
320 | last_fde = buf; | |
321 | /* If we are at the end of the section, we still need to decide | |
322 | on whether to output or discard last encountered CIE (if any). */ | |
323 | if ((bfd_size_type) (buf - ehbuf) == sec->_raw_size) | |
324 | hdr.id = (unsigned int) -1; | |
325 | else | |
326 | { | |
327 | if ((bfd_size_type) (buf + 4 - ehbuf) > sec->_raw_size) | |
328 | /* No space for CIE/FDE header length. */ | |
329 | goto free_no_table; | |
330 | ||
331 | hdr.length = bfd_get_32 (abfd, buf); | |
332 | if (hdr.length == 0xffffffff) | |
333 | /* 64-bit .eh_frame is not supported. */ | |
334 | goto free_no_table; | |
335 | buf += 4; | |
e68cc12e | 336 | if ((bfd_size_type) (buf - ehbuf) + hdr.length > sec->_raw_size) |
65765700 JJ |
337 | /* CIE/FDE not contained fully in this .eh_frame input section. */ |
338 | goto free_no_table; | |
339 | ||
340 | sec_info->entry[sec_info->count].offset = last_fde - ehbuf; | |
341 | sec_info->entry[sec_info->count].size = 4 + hdr.length; | |
342 | ||
343 | if (hdr.length == 0) | |
344 | { | |
345 | /* CIE with length 0 must be only the last in the section. */ | |
346 | if ((bfd_size_type) (buf - ehbuf) < sec->_raw_size) | |
347 | goto free_no_table; | |
348 | ENSURE_NO_RELOCS (buf); | |
349 | sec_info->count++; | |
350 | /* Now just finish last encountered CIE processing and break | |
351 | the loop. */ | |
352 | hdr.id = (unsigned int) -1; | |
353 | } | |
354 | else | |
355 | { | |
356 | hdr.id = bfd_get_32 (abfd, buf); | |
357 | buf += 4; | |
358 | if (hdr.id == (unsigned int) -1) | |
359 | goto free_no_table; | |
360 | } | |
361 | } | |
362 | ||
363 | if (hdr.id == 0 || hdr.id == (unsigned int) -1) | |
364 | { | |
365 | unsigned int initial_insn_length; | |
366 | ||
367 | /* CIE */ | |
368 | if (last_cie != NULL) | |
369 | { | |
73722af0 AM |
370 | /* Now check if this CIE is identical to the last CIE, |
371 | in which case we can remove it provided we adjust | |
372 | all FDEs. Also, it can be removed if we have removed | |
373 | all FDEs using it. */ | |
1049f94e | 374 | if ((!info->relocatable |
9da84788 L |
375 | && hdr_info->last_cie_sec |
376 | && (sec->output_section | |
377 | == hdr_info->last_cie_sec->output_section) | |
73722af0 | 378 | && cie_compare (&cie, &hdr_info->last_cie) == 0) |
65765700 JJ |
379 | || cie_usage_count == 0) |
380 | { | |
381 | new_size -= cie.hdr.length + 4; | |
382 | sec_info->entry[last_cie_ndx].removed = 1; | |
383 | sec_info->entry[last_cie_ndx].sec = hdr_info->last_cie_sec; | |
384 | sec_info->entry[last_cie_ndx].new_offset | |
385 | = hdr_info->last_cie_offset; | |
386 | } | |
387 | else | |
388 | { | |
389 | hdr_info->last_cie = cie; | |
390 | hdr_info->last_cie_sec = sec; | |
391 | hdr_info->last_cie_offset = last_cie - ehbuf; | |
392 | sec_info->entry[last_cie_ndx].make_relative | |
393 | = cie.make_relative; | |
9e2a4898 JJ |
394 | sec_info->entry[last_cie_ndx].make_lsda_relative |
395 | = cie.make_lsda_relative; | |
09ae86c2 JJ |
396 | sec_info->entry[last_cie_ndx].per_encoding_relative |
397 | = (cie.per_encoding & 0x70) == DW_EH_PE_pcrel; | |
65765700 JJ |
398 | } |
399 | } | |
400 | ||
401 | if (hdr.id == (unsigned int) -1) | |
402 | break; | |
403 | ||
404 | last_cie_ndx = sec_info->count; | |
405 | sec_info->entry[sec_info->count].cie = 1; | |
406 | ||
407 | cie_usage_count = 0; | |
408 | memset (&cie, 0, sizeof (cie)); | |
409 | cie.hdr = hdr; | |
410 | cie.version = *buf++; | |
411 | ||
412 | /* Cannot handle unknown versions. */ | |
413 | if (cie.version != 1) | |
414 | goto free_no_table; | |
415 | if (strlen (buf) > sizeof (cie.augmentation) - 1) | |
416 | goto free_no_table; | |
417 | ||
418 | strcpy (cie.augmentation, buf); | |
419 | buf = strchr (buf, '\0') + 1; | |
420 | ENSURE_NO_RELOCS (buf); | |
421 | if (buf[0] == 'e' && buf[1] == 'h') | |
422 | { | |
423 | /* GCC < 3.0 .eh_frame CIE */ | |
424 | /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__ | |
425 | is private to each CIE, so we don't need it for anything. | |
426 | Just skip it. */ | |
427 | buf += ptr_size; | |
428 | SKIP_RELOCS (buf); | |
429 | } | |
430 | read_uleb128 (cie.code_align, buf); | |
431 | read_sleb128 (cie.data_align, buf); | |
7e326afc NC |
432 | /* Note - in DWARF2 the return address column is an unsigned byte. |
433 | In DWARF3 it is a ULEB128. We are following DWARF3. For most | |
434 | ports this will not matter as the value will be less than 128. | |
435 | For the others (eg FRV, SH, MMIX, IA64) they need a fixed GCC | |
436 | which conforms to the DWARF3 standard. */ | |
437 | read_uleb128 (cie.ra_column, buf); | |
65765700 JJ |
438 | ENSURE_NO_RELOCS (buf); |
439 | cie.lsda_encoding = DW_EH_PE_omit; | |
440 | cie.fde_encoding = DW_EH_PE_omit; | |
441 | cie.per_encoding = DW_EH_PE_omit; | |
442 | aug = cie.augmentation; | |
443 | if (aug[0] != 'e' || aug[1] != 'h') | |
444 | { | |
445 | if (*aug == 'z') | |
446 | { | |
447 | aug++; | |
448 | read_uleb128 (cie.augmentation_size, buf); | |
449 | ENSURE_NO_RELOCS (buf); | |
450 | } | |
451 | ||
452 | while (*aug != '\0') | |
453 | switch (*aug++) | |
454 | { | |
455 | case 'L': | |
456 | cie.lsda_encoding = *buf++; | |
457 | ENSURE_NO_RELOCS (buf); | |
458 | if (get_DW_EH_PE_width (cie.lsda_encoding, ptr_size) == 0) | |
459 | goto free_no_table; | |
460 | break; | |
461 | case 'R': | |
462 | cie.fde_encoding = *buf++; | |
463 | ENSURE_NO_RELOCS (buf); | |
464 | if (get_DW_EH_PE_width (cie.fde_encoding, ptr_size) == 0) | |
465 | goto free_no_table; | |
466 | break; | |
467 | case 'P': | |
468 | { | |
469 | int per_width; | |
470 | ||
471 | cie.per_encoding = *buf++; | |
472 | per_width = get_DW_EH_PE_width (cie.per_encoding, | |
473 | ptr_size); | |
474 | if (per_width == 0) | |
475 | goto free_no_table; | |
476 | if ((cie.per_encoding & 0xf0) == DW_EH_PE_aligned) | |
477 | buf = (ehbuf | |
478 | + ((buf - ehbuf + per_width - 1) | |
479 | & ~((bfd_size_type) per_width - 1))); | |
480 | ENSURE_NO_RELOCS (buf); | |
65765700 JJ |
481 | /* Ensure we have a reloc here, against |
482 | a global symbol. */ | |
99eb2ac8 | 483 | if (GET_RELOC (buf) != NULL) |
65765700 JJ |
484 | { |
485 | unsigned long r_symndx; | |
486 | ||
487 | #ifdef BFD64 | |
488 | if (ptr_size == 8) | |
489 | r_symndx = ELF64_R_SYM (cookie->rel->r_info); | |
490 | else | |
491 | #endif | |
492 | r_symndx = ELF32_R_SYM (cookie->rel->r_info); | |
493 | if (r_symndx >= cookie->locsymcount) | |
494 | { | |
495 | struct elf_link_hash_entry *h; | |
496 | ||
497 | r_symndx -= cookie->extsymoff; | |
498 | h = cookie->sym_hashes[r_symndx]; | |
499 | ||
500 | while (h->root.type == bfd_link_hash_indirect | |
501 | || h->root.type == bfd_link_hash_warning) | |
502 | h = (struct elf_link_hash_entry *) | |
503 | h->root.u.i.link; | |
504 | ||
505 | cie.personality = h; | |
506 | } | |
507 | cookie->rel++; | |
508 | } | |
509 | buf += per_width; | |
510 | } | |
511 | break; | |
512 | default: | |
513 | /* Unrecognized augmentation. Better bail out. */ | |
514 | goto free_no_table; | |
515 | } | |
516 | } | |
517 | ||
518 | /* For shared libraries, try to get rid of as many RELATIVE relocs | |
0bb2d96a JJ |
519 | as possible. */ |
520 | if (info->shared | |
ec3391e7 AO |
521 | && (get_elf_backend_data (abfd) |
522 | ->elf_backend_can_make_relative_eh_frame | |
523 | (abfd, info, sec)) | |
65765700 JJ |
524 | && (cie.fde_encoding & 0xf0) == DW_EH_PE_absptr) |
525 | cie.make_relative = 1; | |
526 | ||
0bb2d96a | 527 | if (info->shared |
ec3391e7 AO |
528 | && (get_elf_backend_data (abfd) |
529 | ->elf_backend_can_make_lsda_relative_eh_frame | |
530 | (abfd, info, sec)) | |
9e2a4898 JJ |
531 | && (cie.lsda_encoding & 0xf0) == DW_EH_PE_absptr) |
532 | cie.make_lsda_relative = 1; | |
533 | ||
65765700 JJ |
534 | /* If FDE encoding was not specified, it defaults to |
535 | DW_EH_absptr. */ | |
536 | if (cie.fde_encoding == DW_EH_PE_omit) | |
537 | cie.fde_encoding = DW_EH_PE_absptr; | |
538 | ||
539 | initial_insn_length = cie.hdr.length - (buf - last_fde - 4); | |
540 | if (initial_insn_length <= 50) | |
541 | { | |
542 | cie.initial_insn_length = initial_insn_length; | |
543 | memcpy (cie.initial_instructions, buf, initial_insn_length); | |
544 | } | |
545 | buf += initial_insn_length; | |
546 | ENSURE_NO_RELOCS (buf); | |
547 | last_cie = last_fde; | |
548 | } | |
549 | else | |
550 | { | |
551 | /* Ensure this FDE uses the last CIE encountered. */ | |
552 | if (last_cie == NULL | |
553 | || hdr.id != (unsigned int) (buf - 4 - last_cie)) | |
554 | goto free_no_table; | |
555 | ||
556 | ENSURE_NO_RELOCS (buf); | |
99eb2ac8 | 557 | if (GET_RELOC (buf) == NULL) |
65765700 JJ |
558 | /* This should not happen. */ |
559 | goto free_no_table; | |
560 | if ((*reloc_symbol_deleted_p) (buf - ehbuf, cookie)) | |
561 | { | |
73722af0 | 562 | /* This is a FDE against a discarded section. It should |
65765700 JJ |
563 | be deleted. */ |
564 | new_size -= hdr.length + 4; | |
565 | sec_info->entry[sec_info->count].removed = 1; | |
566 | } | |
567 | else | |
568 | { | |
0bb2d96a | 569 | if (info->shared |
af40ce3c JJ |
570 | && (((cie.fde_encoding & 0xf0) == DW_EH_PE_absptr |
571 | && cie.make_relative == 0) | |
572 | || (cie.fde_encoding & 0xf0) == DW_EH_PE_aligned)) | |
0bb2d96a | 573 | { |
73722af0 | 574 | /* If a shared library uses absolute pointers |
0bb2d96a JJ |
575 | which we cannot turn into PC relative, |
576 | don't create the binary search table, | |
577 | since it is affected by runtime relocations. */ | |
b34976b6 | 578 | hdr_info->table = FALSE; |
0bb2d96a | 579 | } |
65765700 JJ |
580 | cie_usage_count++; |
581 | hdr_info->fde_count++; | |
582 | } | |
9e2a4898 JJ |
583 | if (cie.lsda_encoding != DW_EH_PE_omit) |
584 | { | |
585 | unsigned int dummy; | |
586 | ||
587 | aug = buf; | |
588 | buf += 2 * get_DW_EH_PE_width (cie.fde_encoding, ptr_size); | |
589 | if (cie.augmentation[0] == 'z') | |
590 | read_uleb128 (dummy, buf); | |
591 | /* If some new augmentation data is added before LSDA | |
592 | in FDE augmentation area, this need to be adjusted. */ | |
593 | sec_info->entry[sec_info->count].lsda_offset = (buf - aug); | |
594 | } | |
65765700 JJ |
595 | buf = last_fde + 4 + hdr.length; |
596 | SKIP_RELOCS (buf); | |
597 | } | |
598 | ||
599 | sec_info->entry[sec_info->count].fde_encoding = cie.fde_encoding; | |
9e2a4898 | 600 | sec_info->entry[sec_info->count].lsda_encoding = cie.lsda_encoding; |
65765700 JJ |
601 | sec_info->count++; |
602 | } | |
603 | ||
604 | elf_section_data (sec)->sec_info = sec_info; | |
68bfbfcc | 605 | sec->sec_info_type = ELF_INFO_TYPE_EH_FRAME; |
65765700 JJ |
606 | |
607 | /* Ok, now we can assign new offsets. */ | |
608 | offset = 0; | |
609 | last_cie_ndx = 0; | |
610 | for (i = 0; i < sec_info->count; i++) | |
611 | { | |
612 | if (! sec_info->entry[i].removed) | |
613 | { | |
614 | sec_info->entry[i].new_offset = offset; | |
615 | offset += sec_info->entry[i].size; | |
616 | if (sec_info->entry[i].cie) | |
617 | { | |
618 | last_cie_ndx = i; | |
619 | make_relative = sec_info->entry[i].make_relative; | |
9e2a4898 | 620 | make_lsda_relative = sec_info->entry[i].make_lsda_relative; |
65765700 JJ |
621 | } |
622 | else | |
9e2a4898 JJ |
623 | { |
624 | sec_info->entry[i].make_relative = make_relative; | |
625 | sec_info->entry[i].make_lsda_relative = make_lsda_relative; | |
09ae86c2 | 626 | sec_info->entry[i].per_encoding_relative = 0; |
9e2a4898 | 627 | } |
65765700 JJ |
628 | } |
629 | else if (sec_info->entry[i].cie && sec_info->entry[i].sec == sec) | |
630 | { | |
631 | /* Need to adjust new_offset too. */ | |
632 | BFD_ASSERT (sec_info->entry[last_cie_ndx].offset | |
633 | == sec_info->entry[i].new_offset); | |
634 | sec_info->entry[i].new_offset | |
635 | = sec_info->entry[last_cie_ndx].new_offset; | |
636 | } | |
637 | } | |
638 | if (hdr_info->last_cie_sec == sec) | |
639 | { | |
640 | BFD_ASSERT (sec_info->entry[last_cie_ndx].offset | |
641 | == hdr_info->last_cie_offset); | |
642 | hdr_info->last_cie_offset = sec_info->entry[last_cie_ndx].new_offset; | |
643 | } | |
644 | ||
a5eb27e6 JJ |
645 | /* FIXME: Currently it is not possible to shrink sections to zero size at |
646 | this point, so build a fake minimal CIE. */ | |
647 | if (new_size == 0) | |
648 | new_size = 16; | |
649 | ||
65765700 | 650 | /* Shrink the sec as needed. */ |
65765700 JJ |
651 | sec->_cooked_size = new_size; |
652 | if (sec->_cooked_size == 0) | |
653 | sec->flags |= SEC_EXCLUDE; | |
654 | ||
68f69152 | 655 | free (ehbuf); |
65765700 JJ |
656 | return new_size != sec->_raw_size; |
657 | ||
658 | free_no_table: | |
68f69152 JJ |
659 | if (ehbuf) |
660 | free (ehbuf); | |
65765700 JJ |
661 | if (sec_info) |
662 | free (sec_info); | |
b34976b6 | 663 | hdr_info->table = FALSE; |
65765700 | 664 | hdr_info->last_cie.hdr.length = 0; |
b34976b6 | 665 | return FALSE; |
65765700 JJ |
666 | } |
667 | ||
668 | /* This function is called for .eh_frame_hdr section after | |
669 | _bfd_elf_discard_section_eh_frame has been called on all .eh_frame | |
670 | input sections. It finalizes the size of .eh_frame_hdr section. */ | |
671 | ||
b34976b6 | 672 | bfd_boolean |
c39a58e6 | 673 | _bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
65765700 | 674 | { |
126495ed | 675 | struct elf_link_hash_table *htab; |
65765700 | 676 | struct eh_frame_hdr_info *hdr_info; |
126495ed | 677 | asection *sec; |
65765700 | 678 | |
126495ed AM |
679 | htab = elf_hash_table (info); |
680 | hdr_info = &htab->eh_info; | |
681 | sec = hdr_info->hdr_sec; | |
682 | if (sec == NULL) | |
b34976b6 | 683 | return FALSE; |
126495ed | 684 | |
65765700 JJ |
685 | sec->_cooked_size = EH_FRAME_HDR_SIZE; |
686 | if (hdr_info->table) | |
687 | sec->_cooked_size += 4 + hdr_info->fde_count * 8; | |
688 | ||
689 | /* Request program headers to be recalculated. */ | |
690 | elf_tdata (abfd)->program_header_size = 0; | |
126495ed | 691 | elf_tdata (abfd)->eh_frame_hdr = sec; |
b34976b6 | 692 | return TRUE; |
65765700 JJ |
693 | } |
694 | ||
68f69152 JJ |
695 | /* This function is called from size_dynamic_sections. |
696 | It needs to decide whether .eh_frame_hdr should be output or not, | |
697 | because later on it is too late for calling _bfd_strip_section_from_output, | |
698 | since dynamic symbol table has been sized. */ | |
699 | ||
b34976b6 | 700 | bfd_boolean |
c39a58e6 | 701 | _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info) |
68f69152 | 702 | { |
126495ed | 703 | asection *o; |
68f69152 | 704 | bfd *abfd; |
126495ed | 705 | struct elf_link_hash_table *htab; |
68f69152 JJ |
706 | struct eh_frame_hdr_info *hdr_info; |
707 | ||
126495ed AM |
708 | htab = elf_hash_table (info); |
709 | hdr_info = &htab->eh_info; | |
710 | if (hdr_info->hdr_sec == NULL) | |
b34976b6 | 711 | return TRUE; |
68f69152 | 712 | |
126495ed AM |
713 | if (bfd_is_abs_section (hdr_info->hdr_sec->output_section)) |
714 | { | |
715 | hdr_info->hdr_sec = NULL; | |
b34976b6 | 716 | return TRUE; |
126495ed | 717 | } |
68f69152 JJ |
718 | |
719 | abfd = NULL; | |
720 | if (info->eh_frame_hdr) | |
721 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) | |
722 | { | |
723 | /* Count only sections which have at least a single CIE or FDE. | |
724 | There cannot be any CIE or FDE <= 8 bytes. */ | |
725 | o = bfd_get_section_by_name (abfd, ".eh_frame"); | |
2d653fc7 | 726 | if (o && o->_raw_size > 8 && !bfd_is_abs_section (o->output_section)) |
68f69152 JJ |
727 | break; |
728 | } | |
729 | ||
730 | if (abfd == NULL) | |
731 | { | |
126495ed AM |
732 | _bfd_strip_section_from_output (info, hdr_info->hdr_sec); |
733 | hdr_info->hdr_sec = NULL; | |
b34976b6 | 734 | return TRUE; |
68f69152 | 735 | } |
126495ed | 736 | |
b34976b6 AM |
737 | hdr_info->table = TRUE; |
738 | return TRUE; | |
68f69152 JJ |
739 | } |
740 | ||
65765700 JJ |
741 | /* Adjust an address in the .eh_frame section. Given OFFSET within |
742 | SEC, this returns the new offset in the adjusted .eh_frame section, | |
743 | or -1 if the address refers to a CIE/FDE which has been removed | |
744 | or to offset with dynamic relocation which is no longer needed. */ | |
745 | ||
746 | bfd_vma | |
c39a58e6 AM |
747 | _bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, |
748 | asection *sec, | |
749 | bfd_vma offset) | |
65765700 JJ |
750 | { |
751 | struct eh_frame_sec_info *sec_info; | |
752 | unsigned int lo, hi, mid; | |
753 | ||
68bfbfcc | 754 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
65765700 | 755 | return offset; |
c39a58e6 | 756 | sec_info = elf_section_data (sec)->sec_info; |
65765700 JJ |
757 | |
758 | if (offset >= sec->_raw_size) | |
759 | return offset - (sec->_cooked_size - sec->_raw_size); | |
760 | ||
761 | lo = 0; | |
762 | hi = sec_info->count; | |
763 | mid = 0; | |
764 | while (lo < hi) | |
765 | { | |
766 | mid = (lo + hi) / 2; | |
767 | if (offset < sec_info->entry[mid].offset) | |
768 | hi = mid; | |
769 | else if (offset | |
770 | >= sec_info->entry[mid].offset + sec_info->entry[mid].size) | |
771 | lo = mid + 1; | |
772 | else | |
773 | break; | |
774 | } | |
775 | ||
776 | BFD_ASSERT (lo < hi); | |
777 | ||
778 | /* FDE or CIE was removed. */ | |
779 | if (sec_info->entry[mid].removed) | |
780 | return (bfd_vma) -1; | |
781 | ||
782 | /* If converting to DW_EH_PE_pcrel, there will be no need for run-time | |
783 | relocation against FDE's initial_location field. */ | |
784 | if (sec_info->entry[mid].make_relative | |
785 | && ! sec_info->entry[mid].cie | |
786 | && offset == sec_info->entry[mid].offset + 8) | |
0bb2d96a | 787 | return (bfd_vma) -2; |
65765700 | 788 | |
9e2a4898 JJ |
789 | /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need |
790 | for run-time relocation against LSDA field. */ | |
791 | if (sec_info->entry[mid].make_lsda_relative | |
792 | && ! sec_info->entry[mid].cie | |
126495ed AM |
793 | && (offset == (sec_info->entry[mid].offset + 8 |
794 | + sec_info->entry[mid].lsda_offset))) | |
0bb2d96a | 795 | return (bfd_vma) -2; |
9e2a4898 | 796 | |
c68836a9 AM |
797 | return (offset + sec_info->entry[mid].new_offset |
798 | - sec_info->entry[mid].offset); | |
65765700 JJ |
799 | } |
800 | ||
801 | /* Write out .eh_frame section. This is called with the relocated | |
802 | contents. */ | |
803 | ||
b34976b6 | 804 | bfd_boolean |
c39a58e6 AM |
805 | _bfd_elf_write_section_eh_frame (bfd *abfd, |
806 | struct bfd_link_info *info, | |
807 | asection *sec, | |
808 | bfd_byte *contents) | |
65765700 JJ |
809 | { |
810 | struct eh_frame_sec_info *sec_info; | |
126495ed | 811 | struct elf_link_hash_table *htab; |
65765700 JJ |
812 | struct eh_frame_hdr_info *hdr_info; |
813 | unsigned int i; | |
814 | bfd_byte *p, *buf; | |
815 | unsigned int leb128_tmp; | |
816 | unsigned int cie_offset = 0; | |
817 | unsigned int ptr_size; | |
818 | ||
819 | ptr_size = (elf_elfheader (sec->owner)->e_ident[EI_CLASS] | |
820 | == ELFCLASS64) ? 8 : 4; | |
821 | ||
68bfbfcc | 822 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
c39a58e6 AM |
823 | return bfd_set_section_contents (abfd, sec->output_section, contents, |
824 | sec->output_offset, sec->_raw_size); | |
825 | sec_info = elf_section_data (sec)->sec_info; | |
126495ed AM |
826 | htab = elf_hash_table (info); |
827 | hdr_info = &htab->eh_info; | |
828 | if (hdr_info->table && hdr_info->array == NULL) | |
829 | hdr_info->array | |
830 | = bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array)); | |
831 | if (hdr_info->array == NULL) | |
832 | hdr_info = NULL; | |
65765700 JJ |
833 | |
834 | p = contents; | |
835 | for (i = 0; i < sec_info->count; ++i) | |
836 | { | |
837 | if (sec_info->entry[i].removed) | |
838 | { | |
839 | if (sec_info->entry[i].cie) | |
840 | { | |
a3aa38ee JJ |
841 | /* If CIE is removed due to no remaining FDEs referencing it |
842 | and there were no CIEs kept before it, sec_info->entry[i].sec | |
843 | will be zero. */ | |
844 | if (sec_info->entry[i].sec == NULL) | |
845 | cie_offset = 0; | |
846 | else | |
847 | { | |
848 | cie_offset = sec_info->entry[i].new_offset; | |
849 | cie_offset += (sec_info->entry[i].sec->output_section->vma | |
850 | + sec_info->entry[i].sec->output_offset | |
851 | - sec->output_section->vma | |
852 | - sec->output_offset); | |
853 | } | |
65765700 JJ |
854 | } |
855 | continue; | |
856 | } | |
a3aa38ee | 857 | |
65765700 JJ |
858 | if (sec_info->entry[i].cie) |
859 | { | |
860 | /* CIE */ | |
861 | cie_offset = sec_info->entry[i].new_offset; | |
9e2a4898 | 862 | if (sec_info->entry[i].make_relative |
09ae86c2 JJ |
863 | || sec_info->entry[i].make_lsda_relative |
864 | || sec_info->entry[i].per_encoding_relative) | |
65765700 JJ |
865 | { |
866 | unsigned char *aug; | |
9e2a4898 | 867 | unsigned int action; |
65765700 JJ |
868 | unsigned int dummy, per_width, per_encoding; |
869 | ||
9e2a4898 | 870 | /* Need to find 'R' or 'L' augmentation's argument and modify |
65765700 | 871 | DW_EH_PE_* value. */ |
9e2a4898 | 872 | action = (sec_info->entry[i].make_relative ? 1 : 0) |
09ae86c2 JJ |
873 | | (sec_info->entry[i].make_lsda_relative ? 2 : 0) |
874 | | (sec_info->entry[i].per_encoding_relative ? 4 : 0); | |
65765700 JJ |
875 | buf = contents + sec_info->entry[i].offset; |
876 | /* Skip length, id and version. */ | |
877 | buf += 9; | |
878 | aug = buf; | |
879 | buf = strchr (buf, '\0') + 1; | |
880 | read_uleb128 (dummy, buf); | |
881 | read_sleb128 (dummy, buf); | |
882 | read_uleb128 (dummy, buf); | |
883 | if (*aug == 'z') | |
884 | { | |
885 | read_uleb128 (dummy, buf); | |
886 | aug++; | |
887 | } | |
888 | ||
9e2a4898 | 889 | while (action) |
65765700 JJ |
890 | switch (*aug++) |
891 | { | |
892 | case 'L': | |
9e2a4898 JJ |
893 | if (action & 2) |
894 | { | |
895 | BFD_ASSERT (*buf == sec_info->entry[i].lsda_encoding); | |
896 | *buf |= DW_EH_PE_pcrel; | |
897 | action &= ~2; | |
898 | } | |
65765700 JJ |
899 | buf++; |
900 | break; | |
901 | case 'P': | |
902 | per_encoding = *buf++; | |
903 | per_width = get_DW_EH_PE_width (per_encoding, | |
904 | ptr_size); | |
905 | BFD_ASSERT (per_width != 0); | |
09ae86c2 JJ |
906 | BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel) |
907 | == sec_info->entry[i].per_encoding_relative); | |
65765700 JJ |
908 | if ((per_encoding & 0xf0) == DW_EH_PE_aligned) |
909 | buf = (contents | |
910 | + ((buf - contents + per_width - 1) | |
911 | & ~((bfd_size_type) per_width - 1))); | |
09ae86c2 JJ |
912 | if (action & 4) |
913 | { | |
914 | bfd_vma value; | |
915 | ||
84f97cb6 AS |
916 | value = read_value (abfd, buf, per_width, |
917 | get_DW_EH_PE_signed | |
918 | (per_encoding)); | |
09ae86c2 JJ |
919 | value += (sec_info->entry[i].offset |
920 | - sec_info->entry[i].new_offset); | |
921 | write_value (abfd, buf, value, per_width); | |
922 | action &= ~4; | |
923 | } | |
65765700 JJ |
924 | buf += per_width; |
925 | break; | |
9e2a4898 JJ |
926 | case 'R': |
927 | if (action & 1) | |
928 | { | |
929 | BFD_ASSERT (*buf == sec_info->entry[i].fde_encoding); | |
930 | *buf |= DW_EH_PE_pcrel; | |
931 | action &= ~1; | |
932 | } | |
933 | buf++; | |
934 | break; | |
65765700 JJ |
935 | default: |
936 | BFD_FAIL (); | |
937 | } | |
65765700 JJ |
938 | } |
939 | } | |
af40ce3c | 940 | else if (sec_info->entry[i].size > 4) |
65765700 JJ |
941 | { |
942 | /* FDE */ | |
943 | bfd_vma value = 0, address; | |
9e2a4898 | 944 | unsigned int width; |
65765700 JJ |
945 | |
946 | buf = contents + sec_info->entry[i].offset; | |
b34976b6 | 947 | /* Skip length. */ |
65765700 JJ |
948 | buf += 4; |
949 | bfd_put_32 (abfd, | |
950 | sec_info->entry[i].new_offset + 4 - cie_offset, buf); | |
951 | buf += 4; | |
9e2a4898 JJ |
952 | width = get_DW_EH_PE_width (sec_info->entry[i].fde_encoding, |
953 | ptr_size); | |
84f97cb6 AS |
954 | address = value = read_value (abfd, buf, width, |
955 | get_DW_EH_PE_signed | |
956 | (sec_info->entry[i].fde_encoding)); | |
9e2a4898 | 957 | if (value) |
65765700 | 958 | { |
9e2a4898 JJ |
959 | switch (sec_info->entry[i].fde_encoding & 0xf0) |
960 | { | |
961 | case DW_EH_PE_indirect: | |
962 | case DW_EH_PE_textrel: | |
963 | BFD_ASSERT (hdr_info == NULL); | |
964 | break; | |
965 | case DW_EH_PE_datarel: | |
966 | { | |
967 | asection *got = bfd_get_section_by_name (abfd, ".got"); | |
968 | ||
969 | BFD_ASSERT (got != NULL); | |
970 | address += got->vma; | |
971 | } | |
972 | break; | |
973 | case DW_EH_PE_pcrel: | |
974 | value += (sec_info->entry[i].offset | |
975 | - sec_info->entry[i].new_offset); | |
976 | address += (sec->output_section->vma + sec->output_offset | |
977 | + sec_info->entry[i].offset + 8); | |
978 | break; | |
979 | } | |
980 | if (sec_info->entry[i].make_relative) | |
981 | value -= (sec->output_section->vma + sec->output_offset | |
65765700 | 982 | + sec_info->entry[i].new_offset + 8); |
9e2a4898 | 983 | write_value (abfd, buf, value, width); |
65765700 JJ |
984 | } |
985 | ||
986 | if (hdr_info) | |
987 | { | |
988 | hdr_info->array[hdr_info->array_count].initial_loc = address; | |
989 | hdr_info->array[hdr_info->array_count++].fde | |
990 | = (sec->output_section->vma + sec->output_offset | |
991 | + sec_info->entry[i].new_offset); | |
992 | } | |
9e2a4898 JJ |
993 | |
994 | if ((sec_info->entry[i].lsda_encoding & 0xf0) == DW_EH_PE_pcrel | |
995 | || sec_info->entry[i].make_lsda_relative) | |
996 | { | |
997 | buf += sec_info->entry[i].lsda_offset; | |
998 | width = get_DW_EH_PE_width (sec_info->entry[i].lsda_encoding, | |
999 | ptr_size); | |
84f97cb6 AS |
1000 | value = read_value (abfd, buf, width, |
1001 | get_DW_EH_PE_signed | |
1002 | (sec_info->entry[i].lsda_encoding)); | |
9e2a4898 JJ |
1003 | if (value) |
1004 | { | |
1005 | if ((sec_info->entry[i].lsda_encoding & 0xf0) | |
1006 | == DW_EH_PE_pcrel) | |
1007 | value += (sec_info->entry[i].offset | |
1008 | - sec_info->entry[i].new_offset); | |
1009 | else if (sec_info->entry[i].make_lsda_relative) | |
1010 | value -= (sec->output_section->vma + sec->output_offset | |
1011 | + sec_info->entry[i].new_offset + 8 | |
1012 | + sec_info->entry[i].lsda_offset); | |
1013 | write_value (abfd, buf, value, width); | |
1014 | } | |
1015 | } | |
65765700 | 1016 | } |
af40ce3c JJ |
1017 | else |
1018 | /* Terminating FDE must be at the end of .eh_frame section only. */ | |
1019 | BFD_ASSERT (i == sec_info->count - 1); | |
65765700 JJ |
1020 | |
1021 | BFD_ASSERT (p == contents + sec_info->entry[i].new_offset); | |
1022 | memmove (p, contents + sec_info->entry[i].offset, | |
1023 | sec_info->entry[i].size); | |
1024 | p += sec_info->entry[i].size; | |
1025 | } | |
1026 | ||
a5eb27e6 JJ |
1027 | /* FIXME: Once _bfd_elf_discard_section_eh_frame will be able to |
1028 | shrink sections to zero size, this won't be needed any more. */ | |
1029 | if (p == contents && sec->_cooked_size == 16) | |
1030 | { | |
1031 | bfd_put_32 (abfd, 12, p); /* Fake CIE length */ | |
1032 | bfd_put_32 (abfd, 0, p + 4); /* Fake CIE id */ | |
1033 | p[8] = 1; /* Fake CIE version */ | |
1034 | memset (p + 9, 0, 7); /* Fake CIE augmentation, 3xleb128 | |
1035 | and 3xDW_CFA_nop as pad */ | |
1036 | p += 16; | |
1037 | } | |
10cf14ea L |
1038 | else |
1039 | { | |
1040 | unsigned int alignment = 1 << sec->alignment_power; | |
1041 | unsigned int pad = sec->_cooked_size % alignment; | |
1042 | ||
9da84788 L |
1043 | /* Don't pad beyond the raw size of the output section. It |
1044 | can happen at the last input section. */ | |
1045 | if (pad | |
1046 | && ((sec->output_offset + sec->_cooked_size + pad) | |
1047 | <= sec->output_section->_raw_size)) | |
10cf14ea L |
1048 | { |
1049 | /* Find the last CIE/FDE. */ | |
1050 | for (i = sec_info->count - 1; i > 0; i--) | |
1051 | if (! sec_info->entry[i].removed) | |
1052 | break; | |
1053 | ||
1054 | /* The size of the last CIE/FDE must be at least 4. */ | |
1055 | if (sec_info->entry[i].removed | |
1056 | || sec_info->entry[i].size < 4) | |
1057 | abort (); | |
1058 | ||
1059 | pad = alignment - pad; | |
1060 | ||
1061 | buf = contents + sec_info->entry[i].new_offset; | |
1062 | ||
1063 | /* Update length. */ | |
1064 | sec_info->entry[i].size += pad; | |
1065 | bfd_put_32 (abfd, sec_info->entry[i].size - 4, buf); | |
1066 | ||
1067 | /* Pad it with DW_CFA_nop */ | |
1068 | memset (p, 0, pad); | |
1069 | p += pad; | |
1070 | ||
1071 | sec->_cooked_size += pad; | |
1072 | } | |
1073 | } | |
a5eb27e6 | 1074 | |
65765700 JJ |
1075 | BFD_ASSERT ((bfd_size_type) (p - contents) == sec->_cooked_size); |
1076 | ||
1077 | return bfd_set_section_contents (abfd, sec->output_section, | |
1078 | contents, (file_ptr) sec->output_offset, | |
1079 | sec->_cooked_size); | |
1080 | } | |
1081 | ||
1082 | /* Helper function used to sort .eh_frame_hdr search table by increasing | |
1083 | VMA of FDE initial location. */ | |
1084 | ||
1085 | static int | |
c39a58e6 | 1086 | vma_compare (const void *a, const void *b) |
65765700 | 1087 | { |
c39a58e6 AM |
1088 | const struct eh_frame_array_ent *p = a; |
1089 | const struct eh_frame_array_ent *q = b; | |
65765700 JJ |
1090 | if (p->initial_loc > q->initial_loc) |
1091 | return 1; | |
1092 | if (p->initial_loc < q->initial_loc) | |
1093 | return -1; | |
1094 | return 0; | |
1095 | } | |
1096 | ||
1097 | /* Write out .eh_frame_hdr section. This must be called after | |
1098 | _bfd_elf_write_section_eh_frame has been called on all input | |
1099 | .eh_frame sections. | |
1100 | .eh_frame_hdr format: | |
1101 | ubyte version (currently 1) | |
1102 | ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of | |
1103 | .eh_frame section) | |
1104 | ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count | |
1105 | number (or DW_EH_PE_omit if there is no | |
1106 | binary search table computed)) | |
1107 | ubyte table_enc (DW_EH_PE_* encoding of binary search table, | |
1108 | or DW_EH_PE_omit if not present. | |
1109 | DW_EH_PE_datarel is using address of | |
1110 | .eh_frame_hdr section start as base) | |
1111 | [encoded] eh_frame_ptr (pointer to start of .eh_frame section) | |
1112 | optionally followed by: | |
1113 | [encoded] fde_count (total number of FDEs in .eh_frame section) | |
1114 | fde_count x [encoded] initial_loc, fde | |
1115 | (array of encoded pairs containing | |
1116 | FDE initial_location field and FDE address, | |
5ed6aba4 | 1117 | sorted by increasing initial_loc). */ |
65765700 | 1118 | |
b34976b6 | 1119 | bfd_boolean |
c39a58e6 | 1120 | _bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
65765700 | 1121 | { |
126495ed | 1122 | struct elf_link_hash_table *htab; |
65765700 | 1123 | struct eh_frame_hdr_info *hdr_info; |
126495ed | 1124 | asection *sec; |
65765700 JJ |
1125 | bfd_byte *contents; |
1126 | asection *eh_frame_sec; | |
1127 | bfd_size_type size; | |
5ed6aba4 | 1128 | bfd_boolean retval; |
ec3391e7 | 1129 | bfd_vma encoded_eh_frame; |
65765700 | 1130 | |
126495ed AM |
1131 | htab = elf_hash_table (info); |
1132 | hdr_info = &htab->eh_info; | |
1133 | sec = hdr_info->hdr_sec; | |
1134 | if (sec == NULL) | |
b34976b6 | 1135 | return TRUE; |
57a72197 | 1136 | |
65765700 JJ |
1137 | size = EH_FRAME_HDR_SIZE; |
1138 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) | |
1139 | size += 4 + hdr_info->fde_count * 8; | |
1140 | contents = bfd_malloc (size); | |
1141 | if (contents == NULL) | |
b34976b6 | 1142 | return FALSE; |
65765700 JJ |
1143 | |
1144 | eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame"); | |
1145 | if (eh_frame_sec == NULL) | |
5ed6aba4 NC |
1146 | { |
1147 | free (contents); | |
1148 | return FALSE; | |
1149 | } | |
65765700 JJ |
1150 | |
1151 | memset (contents, 0, EH_FRAME_HDR_SIZE); | |
5ed6aba4 | 1152 | contents[0] = 1; /* Version. */ |
ec3391e7 AO |
1153 | contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address |
1154 | (abfd, info, eh_frame_sec, 0, sec, 4, | |
1155 | &encoded_eh_frame); /* .eh_frame offset. */ | |
1156 | ||
65765700 JJ |
1157 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
1158 | { | |
5ed6aba4 NC |
1159 | contents[2] = DW_EH_PE_udata4; /* FDE count encoding. */ |
1160 | contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; /* Search table enc. */ | |
65765700 JJ |
1161 | } |
1162 | else | |
1163 | { | |
1164 | contents[2] = DW_EH_PE_omit; | |
1165 | contents[3] = DW_EH_PE_omit; | |
1166 | } | |
ec3391e7 AO |
1167 | bfd_put_32 (abfd, encoded_eh_frame, contents + 4); |
1168 | ||
65765700 JJ |
1169 | if (contents[2] != DW_EH_PE_omit) |
1170 | { | |
1171 | unsigned int i; | |
1172 | ||
1173 | bfd_put_32 (abfd, hdr_info->fde_count, contents + EH_FRAME_HDR_SIZE); | |
1174 | qsort (hdr_info->array, hdr_info->fde_count, sizeof (*hdr_info->array), | |
1175 | vma_compare); | |
1176 | for (i = 0; i < hdr_info->fde_count; i++) | |
1177 | { | |
1178 | bfd_put_32 (abfd, | |
1179 | hdr_info->array[i].initial_loc | |
1180 | - sec->output_section->vma, | |
1181 | contents + EH_FRAME_HDR_SIZE + i * 8 + 4); | |
1182 | bfd_put_32 (abfd, | |
1183 | hdr_info->array[i].fde - sec->output_section->vma, | |
1184 | contents + EH_FRAME_HDR_SIZE + i * 8 + 8); | |
1185 | } | |
1186 | } | |
1187 | ||
5ed6aba4 NC |
1188 | retval = bfd_set_section_contents (abfd, sec->output_section, |
1189 | contents, (file_ptr) sec->output_offset, | |
1190 | sec->_cooked_size); | |
1191 | free (contents); | |
1192 | return retval; | |
65765700 | 1193 | } |
ec3391e7 AO |
1194 | |
1195 | /* Decide whether we can use a PC-relative encoding within the given | |
1196 | EH frame section. This is the default implementation. */ | |
1197 | ||
1198 | bfd_boolean | |
1199 | _bfd_elf_can_make_relative (bfd *input_bfd ATTRIBUTE_UNUSED, | |
1200 | struct bfd_link_info *info ATTRIBUTE_UNUSED, | |
1201 | asection *eh_frame_section ATTRIBUTE_UNUSED) | |
1202 | { | |
1203 | return TRUE; | |
1204 | } | |
1205 | ||
1206 | /* Select an encoding for the given address. Preference is given to | |
1207 | PC-relative addressing modes. */ | |
1208 | ||
1209 | bfd_byte | |
1210 | _bfd_elf_encode_eh_address (bfd *abfd ATTRIBUTE_UNUSED, | |
1211 | struct bfd_link_info *info ATTRIBUTE_UNUSED, | |
1212 | asection *osec, bfd_vma offset, | |
1213 | asection *loc_sec, bfd_vma loc_offset, | |
1214 | bfd_vma *encoded) | |
1215 | { | |
1216 | *encoded = osec->vma + offset - | |
1217 | (loc_sec->output_section->vma + loc_sec->output_offset + loc_offset); | |
1218 | return DW_EH_PE_pcrel | DW_EH_PE_sdata4; | |
1219 | } |