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