| 1 | /* .eh_frame section optimization. |
| 2 | Copyright 2001, 2002, 2003 Free Software Foundation, Inc. |
| 3 | Written by Jakub Jelinek <jakub@redhat.com>. |
| 4 | |
| 5 | This file is part of BFD, the Binary File Descriptor library. |
| 6 | |
| 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. |
| 11 | |
| 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. |
| 16 | |
| 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. */ |
| 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 | |
| 29 | /* Helper function for reading uleb128 encoded data. */ |
| 30 | |
| 31 | static bfd_vma |
| 32 | read_unsigned_leb128 (bfd *abfd ATTRIBUTE_UNUSED, |
| 33 | char *buf, |
| 34 | unsigned int *bytes_read_ptr) |
| 35 | { |
| 36 | bfd_vma result; |
| 37 | unsigned int num_read; |
| 38 | int shift; |
| 39 | unsigned char byte; |
| 40 | |
| 41 | result = 0; |
| 42 | shift = 0; |
| 43 | num_read = 0; |
| 44 | do |
| 45 | { |
| 46 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); |
| 47 | buf++; |
| 48 | num_read++; |
| 49 | result |= (((bfd_vma) byte & 0x7f) << shift); |
| 50 | shift += 7; |
| 51 | } |
| 52 | while (byte & 0x80); |
| 53 | *bytes_read_ptr = num_read; |
| 54 | return result; |
| 55 | } |
| 56 | |
| 57 | /* Helper function for reading sleb128 encoded data. */ |
| 58 | |
| 59 | static bfd_signed_vma |
| 60 | read_signed_leb128 (bfd *abfd ATTRIBUTE_UNUSED, |
| 61 | char *buf, |
| 62 | unsigned int * bytes_read_ptr) |
| 63 | { |
| 64 | bfd_vma result; |
| 65 | int shift; |
| 66 | int num_read; |
| 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; |
| 83 | *bytes_read_ptr = num_read; |
| 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 |
| 106 | int get_DW_EH_PE_width (int encoding, int ptr_size) |
| 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 | |
| 126 | #define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0) |
| 127 | |
| 128 | /* Read a width sized value from memory. */ |
| 129 | |
| 130 | static bfd_vma |
| 131 | read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed) |
| 132 | { |
| 133 | bfd_vma value; |
| 134 | |
| 135 | switch (width) |
| 136 | { |
| 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; |
| 158 | } |
| 159 | |
| 160 | return value; |
| 161 | } |
| 162 | |
| 163 | /* Store a width sized value to memory. */ |
| 164 | |
| 165 | static void |
| 166 | write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width) |
| 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 | |
| 177 | /* Return zero if C1 and C2 CIEs can be merged. */ |
| 178 | |
| 179 | static |
| 180 | int cie_compare (struct cie *c1, struct cie *c2) |
| 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 |
| 194 | && c1->initial_insn_length == c2->initial_insn_length |
| 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 |
| 205 | functions. The function returns TRUE iff any entries have been |
| 206 | deleted. */ |
| 207 | |
| 208 | bfd_boolean |
| 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) |
| 213 | { |
| 214 | bfd_byte *ehbuf = NULL, *buf; |
| 215 | bfd_byte *last_cie, *last_fde; |
| 216 | struct cie_header hdr; |
| 217 | struct cie cie; |
| 218 | struct elf_link_hash_table *htab; |
| 219 | struct eh_frame_hdr_info *hdr_info; |
| 220 | struct eh_frame_sec_info *sec_info = NULL; |
| 221 | unsigned int leb128_tmp; |
| 222 | unsigned int cie_usage_count, last_cie_ndx, i, offset; |
| 223 | unsigned int make_relative, make_lsda_relative; |
| 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. */ |
| 230 | return FALSE; |
| 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. */ |
| 238 | return FALSE; |
| 239 | } |
| 240 | |
| 241 | htab = elf_hash_table (info); |
| 242 | hdr_info = &htab->eh_info; |
| 243 | |
| 244 | /* Read the frame unwind information from abfd. */ |
| 245 | |
| 246 | ehbuf = bfd_malloc (sec->_raw_size); |
| 247 | if (ehbuf == NULL) |
| 248 | goto free_no_table; |
| 249 | |
| 250 | if (! bfd_get_section_contents (abfd, sec, ehbuf, 0, sec->_raw_size)) |
| 251 | goto free_no_table; |
| 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); |
| 259 | return FALSE; |
| 260 | } |
| 261 | |
| 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) |
| 265 | goto free_no_table; |
| 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; |
| 276 | make_lsda_relative = hdr_info->last_cie.make_lsda_relative; |
| 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 \ |
| 286 | < (bfd_size_type) ((buf) - ehbuf)) \ |
| 287 | && cookie->rel->r_info != 0) \ |
| 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; |
| 336 | if ((bfd_size_type) (buf - ehbuf) + hdr.length > sec->_raw_size) |
| 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 | { |
| 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. */ |
| 374 | if ((!info->relocatable |
| 375 | && hdr_info->last_cie_sec |
| 376 | && (sec->output_section |
| 377 | == hdr_info->last_cie_sec->output_section) |
| 378 | && cie_compare (&cie, &hdr_info->last_cie) == 0) |
| 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; |
| 394 | sec_info->entry[last_cie_ndx].make_lsda_relative |
| 395 | = cie.make_lsda_relative; |
| 396 | sec_info->entry[last_cie_ndx].per_encoding_relative |
| 397 | = (cie.per_encoding & 0x70) == DW_EH_PE_pcrel; |
| 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); |
| 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); |
| 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); |
| 481 | /* Ensure we have a reloc here, against |
| 482 | a global symbol. */ |
| 483 | if (GET_RELOC (buf) != NULL) |
| 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 |
| 519 | as possible. */ |
| 520 | if (info->shared |
| 521 | && (get_elf_backend_data (abfd) |
| 522 | ->elf_backend_can_make_relative_eh_frame |
| 523 | (abfd, info, sec)) |
| 524 | && (cie.fde_encoding & 0xf0) == DW_EH_PE_absptr) |
| 525 | cie.make_relative = 1; |
| 526 | |
| 527 | if (info->shared |
| 528 | && (get_elf_backend_data (abfd) |
| 529 | ->elf_backend_can_make_lsda_relative_eh_frame |
| 530 | (abfd, info, sec)) |
| 531 | && (cie.lsda_encoding & 0xf0) == DW_EH_PE_absptr) |
| 532 | cie.make_lsda_relative = 1; |
| 533 | |
| 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); |
| 557 | if (GET_RELOC (buf) == NULL) |
| 558 | /* This should not happen. */ |
| 559 | goto free_no_table; |
| 560 | if ((*reloc_symbol_deleted_p) (buf - ehbuf, cookie)) |
| 561 | { |
| 562 | /* This is a FDE against a discarded section. It should |
| 563 | be deleted. */ |
| 564 | new_size -= hdr.length + 4; |
| 565 | sec_info->entry[sec_info->count].removed = 1; |
| 566 | } |
| 567 | else |
| 568 | { |
| 569 | if (info->shared |
| 570 | && (((cie.fde_encoding & 0xf0) == DW_EH_PE_absptr |
| 571 | && cie.make_relative == 0) |
| 572 | || (cie.fde_encoding & 0xf0) == DW_EH_PE_aligned)) |
| 573 | { |
| 574 | /* If a shared library uses absolute pointers |
| 575 | which we cannot turn into PC relative, |
| 576 | don't create the binary search table, |
| 577 | since it is affected by runtime relocations. */ |
| 578 | hdr_info->table = FALSE; |
| 579 | } |
| 580 | cie_usage_count++; |
| 581 | hdr_info->fde_count++; |
| 582 | } |
| 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 | } |
| 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; |
| 600 | sec_info->entry[sec_info->count].lsda_encoding = cie.lsda_encoding; |
| 601 | sec_info->count++; |
| 602 | } |
| 603 | |
| 604 | elf_section_data (sec)->sec_info = sec_info; |
| 605 | sec->sec_info_type = ELF_INFO_TYPE_EH_FRAME; |
| 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; |
| 620 | make_lsda_relative = sec_info->entry[i].make_lsda_relative; |
| 621 | } |
| 622 | else |
| 623 | { |
| 624 | sec_info->entry[i].make_relative = make_relative; |
| 625 | sec_info->entry[i].make_lsda_relative = make_lsda_relative; |
| 626 | sec_info->entry[i].per_encoding_relative = 0; |
| 627 | } |
| 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 | |
| 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 | |
| 650 | /* Shrink the sec as needed. */ |
| 651 | sec->_cooked_size = new_size; |
| 652 | if (sec->_cooked_size == 0) |
| 653 | sec->flags |= SEC_EXCLUDE; |
| 654 | |
| 655 | free (ehbuf); |
| 656 | return new_size != sec->_raw_size; |
| 657 | |
| 658 | free_no_table: |
| 659 | if (ehbuf) |
| 660 | free (ehbuf); |
| 661 | if (sec_info) |
| 662 | free (sec_info); |
| 663 | hdr_info->table = FALSE; |
| 664 | hdr_info->last_cie.hdr.length = 0; |
| 665 | return FALSE; |
| 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 | |
| 672 | bfd_boolean |
| 673 | _bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 674 | { |
| 675 | struct elf_link_hash_table *htab; |
| 676 | struct eh_frame_hdr_info *hdr_info; |
| 677 | asection *sec; |
| 678 | |
| 679 | htab = elf_hash_table (info); |
| 680 | hdr_info = &htab->eh_info; |
| 681 | sec = hdr_info->hdr_sec; |
| 682 | if (sec == NULL) |
| 683 | return FALSE; |
| 684 | |
| 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; |
| 691 | elf_tdata (abfd)->eh_frame_hdr = sec; |
| 692 | return TRUE; |
| 693 | } |
| 694 | |
| 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 | |
| 700 | bfd_boolean |
| 701 | _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info) |
| 702 | { |
| 703 | asection *o; |
| 704 | bfd *abfd; |
| 705 | struct elf_link_hash_table *htab; |
| 706 | struct eh_frame_hdr_info *hdr_info; |
| 707 | |
| 708 | htab = elf_hash_table (info); |
| 709 | hdr_info = &htab->eh_info; |
| 710 | if (hdr_info->hdr_sec == NULL) |
| 711 | return TRUE; |
| 712 | |
| 713 | if (bfd_is_abs_section (hdr_info->hdr_sec->output_section)) |
| 714 | { |
| 715 | hdr_info->hdr_sec = NULL; |
| 716 | return TRUE; |
| 717 | } |
| 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"); |
| 726 | if (o && o->_raw_size > 8 && !bfd_is_abs_section (o->output_section)) |
| 727 | break; |
| 728 | } |
| 729 | |
| 730 | if (abfd == NULL) |
| 731 | { |
| 732 | _bfd_strip_section_from_output (info, hdr_info->hdr_sec); |
| 733 | hdr_info->hdr_sec = NULL; |
| 734 | return TRUE; |
| 735 | } |
| 736 | |
| 737 | hdr_info->table = TRUE; |
| 738 | return TRUE; |
| 739 | } |
| 740 | |
| 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 |
| 747 | _bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, |
| 748 | asection *sec, |
| 749 | bfd_vma offset) |
| 750 | { |
| 751 | struct eh_frame_sec_info *sec_info; |
| 752 | unsigned int lo, hi, mid; |
| 753 | |
| 754 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 755 | return offset; |
| 756 | sec_info = elf_section_data (sec)->sec_info; |
| 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) |
| 787 | return (bfd_vma) -2; |
| 788 | |
| 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 |
| 793 | && (offset == (sec_info->entry[mid].offset + 8 |
| 794 | + sec_info->entry[mid].lsda_offset))) |
| 795 | return (bfd_vma) -2; |
| 796 | |
| 797 | return (offset + sec_info->entry[mid].new_offset |
| 798 | - sec_info->entry[mid].offset); |
| 799 | } |
| 800 | |
| 801 | /* Write out .eh_frame section. This is called with the relocated |
| 802 | contents. */ |
| 803 | |
| 804 | bfd_boolean |
| 805 | _bfd_elf_write_section_eh_frame (bfd *abfd, |
| 806 | struct bfd_link_info *info, |
| 807 | asection *sec, |
| 808 | bfd_byte *contents) |
| 809 | { |
| 810 | struct eh_frame_sec_info *sec_info; |
| 811 | struct elf_link_hash_table *htab; |
| 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 | |
| 822 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 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; |
| 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; |
| 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 | { |
| 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 | } |
| 854 | } |
| 855 | continue; |
| 856 | } |
| 857 | |
| 858 | if (sec_info->entry[i].cie) |
| 859 | { |
| 860 | /* CIE */ |
| 861 | cie_offset = sec_info->entry[i].new_offset; |
| 862 | if (sec_info->entry[i].make_relative |
| 863 | || sec_info->entry[i].make_lsda_relative |
| 864 | || sec_info->entry[i].per_encoding_relative) |
| 865 | { |
| 866 | unsigned char *aug; |
| 867 | unsigned int action; |
| 868 | unsigned int dummy, per_width, per_encoding; |
| 869 | |
| 870 | /* Need to find 'R' or 'L' augmentation's argument and modify |
| 871 | DW_EH_PE_* value. */ |
| 872 | action = (sec_info->entry[i].make_relative ? 1 : 0) |
| 873 | | (sec_info->entry[i].make_lsda_relative ? 2 : 0) |
| 874 | | (sec_info->entry[i].per_encoding_relative ? 4 : 0); |
| 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 | |
| 889 | while (action) |
| 890 | switch (*aug++) |
| 891 | { |
| 892 | case 'L': |
| 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 | } |
| 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); |
| 906 | BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel) |
| 907 | == sec_info->entry[i].per_encoding_relative); |
| 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))); |
| 912 | if (action & 4) |
| 913 | { |
| 914 | bfd_vma value; |
| 915 | |
| 916 | value = read_value (abfd, buf, per_width, |
| 917 | get_DW_EH_PE_signed |
| 918 | (per_encoding)); |
| 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 | } |
| 924 | buf += per_width; |
| 925 | break; |
| 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; |
| 935 | default: |
| 936 | BFD_FAIL (); |
| 937 | } |
| 938 | } |
| 939 | } |
| 940 | else if (sec_info->entry[i].size > 4) |
| 941 | { |
| 942 | /* FDE */ |
| 943 | bfd_vma value = 0, address; |
| 944 | unsigned int width; |
| 945 | |
| 946 | buf = contents + sec_info->entry[i].offset; |
| 947 | /* Skip length. */ |
| 948 | buf += 4; |
| 949 | bfd_put_32 (abfd, |
| 950 | sec_info->entry[i].new_offset + 4 - cie_offset, buf); |
| 951 | buf += 4; |
| 952 | width = get_DW_EH_PE_width (sec_info->entry[i].fde_encoding, |
| 953 | ptr_size); |
| 954 | address = value = read_value (abfd, buf, width, |
| 955 | get_DW_EH_PE_signed |
| 956 | (sec_info->entry[i].fde_encoding)); |
| 957 | if (value) |
| 958 | { |
| 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 |
| 982 | + sec_info->entry[i].new_offset + 8); |
| 983 | write_value (abfd, buf, value, width); |
| 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 | } |
| 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); |
| 1000 | value = read_value (abfd, buf, width, |
| 1001 | get_DW_EH_PE_signed |
| 1002 | (sec_info->entry[i].lsda_encoding)); |
| 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 | } |
| 1016 | } |
| 1017 | else |
| 1018 | /* Terminating FDE must be at the end of .eh_frame section only. */ |
| 1019 | BFD_ASSERT (i == sec_info->count - 1); |
| 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 | |
| 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 | } |
| 1038 | else |
| 1039 | { |
| 1040 | unsigned int alignment = 1 << sec->alignment_power; |
| 1041 | unsigned int pad = sec->_cooked_size % alignment; |
| 1042 | |
| 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)) |
| 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 | } |
| 1074 | |
| 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 |
| 1086 | vma_compare (const void *a, const void *b) |
| 1087 | { |
| 1088 | const struct eh_frame_array_ent *p = a; |
| 1089 | const struct eh_frame_array_ent *q = b; |
| 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, |
| 1117 | sorted by increasing initial_loc). */ |
| 1118 | |
| 1119 | bfd_boolean |
| 1120 | _bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 1121 | { |
| 1122 | struct elf_link_hash_table *htab; |
| 1123 | struct eh_frame_hdr_info *hdr_info; |
| 1124 | asection *sec; |
| 1125 | bfd_byte *contents; |
| 1126 | asection *eh_frame_sec; |
| 1127 | bfd_size_type size; |
| 1128 | bfd_boolean retval; |
| 1129 | bfd_vma encoded_eh_frame; |
| 1130 | |
| 1131 | htab = elf_hash_table (info); |
| 1132 | hdr_info = &htab->eh_info; |
| 1133 | sec = hdr_info->hdr_sec; |
| 1134 | if (sec == NULL) |
| 1135 | return TRUE; |
| 1136 | |
| 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) |
| 1142 | return FALSE; |
| 1143 | |
| 1144 | eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame"); |
| 1145 | if (eh_frame_sec == NULL) |
| 1146 | { |
| 1147 | free (contents); |
| 1148 | return FALSE; |
| 1149 | } |
| 1150 | |
| 1151 | memset (contents, 0, EH_FRAME_HDR_SIZE); |
| 1152 | contents[0] = 1; /* Version. */ |
| 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 | |
| 1157 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
| 1158 | { |
| 1159 | contents[2] = DW_EH_PE_udata4; /* FDE count encoding. */ |
| 1160 | contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; /* Search table enc. */ |
| 1161 | } |
| 1162 | else |
| 1163 | { |
| 1164 | contents[2] = DW_EH_PE_omit; |
| 1165 | contents[3] = DW_EH_PE_omit; |
| 1166 | } |
| 1167 | bfd_put_32 (abfd, encoded_eh_frame, contents + 4); |
| 1168 | |
| 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 | |
| 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; |
| 1193 | } |
| 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 | } |