| 1 | /* .eh_frame section optimization. |
| 2 | Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007 |
| 3 | Free Software Foundation, Inc. |
| 4 | Written by Jakub Jelinek <jakub@redhat.com>. |
| 5 | |
| 6 | This file is part of BFD, the Binary File Descriptor library. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | MA 02110-1301, USA. */ |
| 22 | |
| 23 | #include "sysdep.h" |
| 24 | #include "bfd.h" |
| 25 | #include "libbfd.h" |
| 26 | #include "elf-bfd.h" |
| 27 | #include "elf/dwarf2.h" |
| 28 | |
| 29 | #define EH_FRAME_HDR_SIZE 8 |
| 30 | |
| 31 | struct cie |
| 32 | { |
| 33 | unsigned int length; |
| 34 | unsigned int hash; |
| 35 | unsigned char version; |
| 36 | unsigned char local_personality; |
| 37 | char augmentation[20]; |
| 38 | bfd_vma code_align; |
| 39 | bfd_signed_vma data_align; |
| 40 | bfd_vma ra_column; |
| 41 | bfd_vma augmentation_size; |
| 42 | union { |
| 43 | struct elf_link_hash_entry *h; |
| 44 | bfd_vma val; |
| 45 | unsigned int reloc_index; |
| 46 | } personality; |
| 47 | asection *output_sec; |
| 48 | struct eh_cie_fde *cie_inf; |
| 49 | unsigned char per_encoding; |
| 50 | unsigned char lsda_encoding; |
| 51 | unsigned char fde_encoding; |
| 52 | unsigned char initial_insn_length; |
| 53 | unsigned char can_make_lsda_relative; |
| 54 | unsigned char initial_instructions[50]; |
| 55 | }; |
| 56 | |
| 57 | |
| 58 | |
| 59 | /* If *ITER hasn't reached END yet, read the next byte into *RESULT and |
| 60 | move onto the next byte. Return true on success. */ |
| 61 | |
| 62 | static inline bfd_boolean |
| 63 | read_byte (bfd_byte **iter, bfd_byte *end, unsigned char *result) |
| 64 | { |
| 65 | if (*iter >= end) |
| 66 | return FALSE; |
| 67 | *result = *((*iter)++); |
| 68 | return TRUE; |
| 69 | } |
| 70 | |
| 71 | /* Move *ITER over LENGTH bytes, or up to END, whichever is closer. |
| 72 | Return true it was possible to move LENGTH bytes. */ |
| 73 | |
| 74 | static inline bfd_boolean |
| 75 | skip_bytes (bfd_byte **iter, bfd_byte *end, bfd_size_type length) |
| 76 | { |
| 77 | if ((bfd_size_type) (end - *iter) < length) |
| 78 | { |
| 79 | *iter = end; |
| 80 | return FALSE; |
| 81 | } |
| 82 | *iter += length; |
| 83 | return TRUE; |
| 84 | } |
| 85 | |
| 86 | /* Move *ITER over an leb128, stopping at END. Return true if the end |
| 87 | of the leb128 was found. */ |
| 88 | |
| 89 | static bfd_boolean |
| 90 | skip_leb128 (bfd_byte **iter, bfd_byte *end) |
| 91 | { |
| 92 | unsigned char byte; |
| 93 | do |
| 94 | if (!read_byte (iter, end, &byte)) |
| 95 | return FALSE; |
| 96 | while (byte & 0x80); |
| 97 | return TRUE; |
| 98 | } |
| 99 | |
| 100 | /* Like skip_leb128, but treat the leb128 as an unsigned value and |
| 101 | store it in *VALUE. */ |
| 102 | |
| 103 | static bfd_boolean |
| 104 | read_uleb128 (bfd_byte **iter, bfd_byte *end, bfd_vma *value) |
| 105 | { |
| 106 | bfd_byte *start, *p; |
| 107 | |
| 108 | start = *iter; |
| 109 | if (!skip_leb128 (iter, end)) |
| 110 | return FALSE; |
| 111 | |
| 112 | p = *iter; |
| 113 | *value = *--p; |
| 114 | while (p > start) |
| 115 | *value = (*value << 7) | (*--p & 0x7f); |
| 116 | |
| 117 | return TRUE; |
| 118 | } |
| 119 | |
| 120 | /* Like read_uleb128, but for signed values. */ |
| 121 | |
| 122 | static bfd_boolean |
| 123 | read_sleb128 (bfd_byte **iter, bfd_byte *end, bfd_signed_vma *value) |
| 124 | { |
| 125 | bfd_byte *start, *p; |
| 126 | |
| 127 | start = *iter; |
| 128 | if (!skip_leb128 (iter, end)) |
| 129 | return FALSE; |
| 130 | |
| 131 | p = *iter; |
| 132 | *value = ((*--p & 0x7f) ^ 0x40) - 0x40; |
| 133 | while (p > start) |
| 134 | *value = (*value << 7) | (*--p & 0x7f); |
| 135 | |
| 136 | return TRUE; |
| 137 | } |
| 138 | |
| 139 | /* Return 0 if either encoding is variable width, or not yet known to bfd. */ |
| 140 | |
| 141 | static |
| 142 | int get_DW_EH_PE_width (int encoding, int ptr_size) |
| 143 | { |
| 144 | /* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame |
| 145 | was added to bfd. */ |
| 146 | if ((encoding & 0x60) == 0x60) |
| 147 | return 0; |
| 148 | |
| 149 | switch (encoding & 7) |
| 150 | { |
| 151 | case DW_EH_PE_udata2: return 2; |
| 152 | case DW_EH_PE_udata4: return 4; |
| 153 | case DW_EH_PE_udata8: return 8; |
| 154 | case DW_EH_PE_absptr: return ptr_size; |
| 155 | default: |
| 156 | break; |
| 157 | } |
| 158 | |
| 159 | return 0; |
| 160 | } |
| 161 | |
| 162 | #define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0) |
| 163 | |
| 164 | /* Read a width sized value from memory. */ |
| 165 | |
| 166 | static bfd_vma |
| 167 | read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed) |
| 168 | { |
| 169 | bfd_vma value; |
| 170 | |
| 171 | switch (width) |
| 172 | { |
| 173 | case 2: |
| 174 | if (is_signed) |
| 175 | value = bfd_get_signed_16 (abfd, buf); |
| 176 | else |
| 177 | value = bfd_get_16 (abfd, buf); |
| 178 | break; |
| 179 | case 4: |
| 180 | if (is_signed) |
| 181 | value = bfd_get_signed_32 (abfd, buf); |
| 182 | else |
| 183 | value = bfd_get_32 (abfd, buf); |
| 184 | break; |
| 185 | case 8: |
| 186 | if (is_signed) |
| 187 | value = bfd_get_signed_64 (abfd, buf); |
| 188 | else |
| 189 | value = bfd_get_64 (abfd, buf); |
| 190 | break; |
| 191 | default: |
| 192 | BFD_FAIL (); |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | return value; |
| 197 | } |
| 198 | |
| 199 | /* Store a width sized value to memory. */ |
| 200 | |
| 201 | static void |
| 202 | write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width) |
| 203 | { |
| 204 | switch (width) |
| 205 | { |
| 206 | case 2: bfd_put_16 (abfd, value, buf); break; |
| 207 | case 4: bfd_put_32 (abfd, value, buf); break; |
| 208 | case 8: bfd_put_64 (abfd, value, buf); break; |
| 209 | default: BFD_FAIL (); |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | /* Return one if C1 and C2 CIEs can be merged. */ |
| 214 | |
| 215 | static int |
| 216 | cie_eq (const void *e1, const void *e2) |
| 217 | { |
| 218 | const struct cie *c1 = e1; |
| 219 | const struct cie *c2 = e2; |
| 220 | |
| 221 | if (c1->hash == c2->hash |
| 222 | && c1->length == c2->length |
| 223 | && c1->version == c2->version |
| 224 | && c1->local_personality == c2->local_personality |
| 225 | && strcmp (c1->augmentation, c2->augmentation) == 0 |
| 226 | && strcmp (c1->augmentation, "eh") != 0 |
| 227 | && c1->code_align == c2->code_align |
| 228 | && c1->data_align == c2->data_align |
| 229 | && c1->ra_column == c2->ra_column |
| 230 | && c1->augmentation_size == c2->augmentation_size |
| 231 | && memcmp (&c1->personality, &c2->personality, |
| 232 | sizeof (c1->personality)) == 0 |
| 233 | && c1->output_sec == c2->output_sec |
| 234 | && c1->per_encoding == c2->per_encoding |
| 235 | && c1->lsda_encoding == c2->lsda_encoding |
| 236 | && c1->fde_encoding == c2->fde_encoding |
| 237 | && c1->initial_insn_length == c2->initial_insn_length |
| 238 | && memcmp (c1->initial_instructions, |
| 239 | c2->initial_instructions, |
| 240 | c1->initial_insn_length) == 0) |
| 241 | return 1; |
| 242 | |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | static hashval_t |
| 247 | cie_hash (const void *e) |
| 248 | { |
| 249 | const struct cie *c = e; |
| 250 | return c->hash; |
| 251 | } |
| 252 | |
| 253 | static hashval_t |
| 254 | cie_compute_hash (struct cie *c) |
| 255 | { |
| 256 | hashval_t h = 0; |
| 257 | h = iterative_hash_object (c->length, h); |
| 258 | h = iterative_hash_object (c->version, h); |
| 259 | h = iterative_hash (c->augmentation, strlen (c->augmentation) + 1, h); |
| 260 | h = iterative_hash_object (c->code_align, h); |
| 261 | h = iterative_hash_object (c->data_align, h); |
| 262 | h = iterative_hash_object (c->ra_column, h); |
| 263 | h = iterative_hash_object (c->augmentation_size, h); |
| 264 | h = iterative_hash_object (c->personality, h); |
| 265 | h = iterative_hash_object (c->output_sec, h); |
| 266 | h = iterative_hash_object (c->per_encoding, h); |
| 267 | h = iterative_hash_object (c->lsda_encoding, h); |
| 268 | h = iterative_hash_object (c->fde_encoding, h); |
| 269 | h = iterative_hash_object (c->initial_insn_length, h); |
| 270 | h = iterative_hash (c->initial_instructions, c->initial_insn_length, h); |
| 271 | c->hash = h; |
| 272 | return h; |
| 273 | } |
| 274 | |
| 275 | /* Return the number of extra bytes that we'll be inserting into |
| 276 | ENTRY's augmentation string. */ |
| 277 | |
| 278 | static INLINE unsigned int |
| 279 | extra_augmentation_string_bytes (struct eh_cie_fde *entry) |
| 280 | { |
| 281 | unsigned int size = 0; |
| 282 | if (entry->cie) |
| 283 | { |
| 284 | if (entry->add_augmentation_size) |
| 285 | size++; |
| 286 | if (entry->u.cie.add_fde_encoding) |
| 287 | size++; |
| 288 | } |
| 289 | return size; |
| 290 | } |
| 291 | |
| 292 | /* Likewise ENTRY's augmentation data. */ |
| 293 | |
| 294 | static INLINE unsigned int |
| 295 | extra_augmentation_data_bytes (struct eh_cie_fde *entry) |
| 296 | { |
| 297 | unsigned int size = 0; |
| 298 | if (entry->add_augmentation_size) |
| 299 | size++; |
| 300 | if (entry->cie && entry->u.cie.add_fde_encoding) |
| 301 | size++; |
| 302 | return size; |
| 303 | } |
| 304 | |
| 305 | /* Return the size that ENTRY will have in the output. ALIGNMENT is the |
| 306 | required alignment of ENTRY in bytes. */ |
| 307 | |
| 308 | static unsigned int |
| 309 | size_of_output_cie_fde (struct eh_cie_fde *entry, unsigned int alignment) |
| 310 | { |
| 311 | if (entry->removed) |
| 312 | return 0; |
| 313 | if (entry->size == 4) |
| 314 | return 4; |
| 315 | return (entry->size |
| 316 | + extra_augmentation_string_bytes (entry) |
| 317 | + extra_augmentation_data_bytes (entry) |
| 318 | + alignment - 1) & -alignment; |
| 319 | } |
| 320 | |
| 321 | /* Assume that the bytes between *ITER and END are CFA instructions. |
| 322 | Try to move *ITER past the first instruction and return true on |
| 323 | success. ENCODED_PTR_WIDTH gives the width of pointer entries. */ |
| 324 | |
| 325 | static bfd_boolean |
| 326 | skip_cfa_op (bfd_byte **iter, bfd_byte *end, unsigned int encoded_ptr_width) |
| 327 | { |
| 328 | bfd_byte op; |
| 329 | bfd_vma length; |
| 330 | |
| 331 | if (!read_byte (iter, end, &op)) |
| 332 | return FALSE; |
| 333 | |
| 334 | switch (op & 0xc0 ? op & 0xc0 : op) |
| 335 | { |
| 336 | case DW_CFA_nop: |
| 337 | case DW_CFA_advance_loc: |
| 338 | case DW_CFA_restore: |
| 339 | case DW_CFA_remember_state: |
| 340 | case DW_CFA_restore_state: |
| 341 | case DW_CFA_GNU_window_save: |
| 342 | /* No arguments. */ |
| 343 | return TRUE; |
| 344 | |
| 345 | case DW_CFA_offset: |
| 346 | case DW_CFA_restore_extended: |
| 347 | case DW_CFA_undefined: |
| 348 | case DW_CFA_same_value: |
| 349 | case DW_CFA_def_cfa_register: |
| 350 | case DW_CFA_def_cfa_offset: |
| 351 | case DW_CFA_def_cfa_offset_sf: |
| 352 | case DW_CFA_GNU_args_size: |
| 353 | /* One leb128 argument. */ |
| 354 | return skip_leb128 (iter, end); |
| 355 | |
| 356 | case DW_CFA_val_offset: |
| 357 | case DW_CFA_val_offset_sf: |
| 358 | case DW_CFA_offset_extended: |
| 359 | case DW_CFA_register: |
| 360 | case DW_CFA_def_cfa: |
| 361 | case DW_CFA_offset_extended_sf: |
| 362 | case DW_CFA_GNU_negative_offset_extended: |
| 363 | case DW_CFA_def_cfa_sf: |
| 364 | /* Two leb128 arguments. */ |
| 365 | return (skip_leb128 (iter, end) |
| 366 | && skip_leb128 (iter, end)); |
| 367 | |
| 368 | case DW_CFA_def_cfa_expression: |
| 369 | /* A variable-length argument. */ |
| 370 | return (read_uleb128 (iter, end, &length) |
| 371 | && skip_bytes (iter, end, length)); |
| 372 | |
| 373 | case DW_CFA_expression: |
| 374 | case DW_CFA_val_expression: |
| 375 | /* A leb128 followed by a variable-length argument. */ |
| 376 | return (skip_leb128 (iter, end) |
| 377 | && read_uleb128 (iter, end, &length) |
| 378 | && skip_bytes (iter, end, length)); |
| 379 | |
| 380 | case DW_CFA_set_loc: |
| 381 | return skip_bytes (iter, end, encoded_ptr_width); |
| 382 | |
| 383 | case DW_CFA_advance_loc1: |
| 384 | return skip_bytes (iter, end, 1); |
| 385 | |
| 386 | case DW_CFA_advance_loc2: |
| 387 | return skip_bytes (iter, end, 2); |
| 388 | |
| 389 | case DW_CFA_advance_loc4: |
| 390 | return skip_bytes (iter, end, 4); |
| 391 | |
| 392 | case DW_CFA_MIPS_advance_loc8: |
| 393 | return skip_bytes (iter, end, 8); |
| 394 | |
| 395 | default: |
| 396 | return FALSE; |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | /* Try to interpret the bytes between BUF and END as CFA instructions. |
| 401 | If every byte makes sense, return a pointer to the first DW_CFA_nop |
| 402 | padding byte, or END if there is no padding. Return null otherwise. |
| 403 | ENCODED_PTR_WIDTH is as for skip_cfa_op. */ |
| 404 | |
| 405 | static bfd_byte * |
| 406 | skip_non_nops (bfd_byte *buf, bfd_byte *end, unsigned int encoded_ptr_width, |
| 407 | unsigned int *set_loc_count) |
| 408 | { |
| 409 | bfd_byte *last; |
| 410 | |
| 411 | last = buf; |
| 412 | while (buf < end) |
| 413 | if (*buf == DW_CFA_nop) |
| 414 | buf++; |
| 415 | else |
| 416 | { |
| 417 | if (*buf == DW_CFA_set_loc) |
| 418 | ++*set_loc_count; |
| 419 | if (!skip_cfa_op (&buf, end, encoded_ptr_width)) |
| 420 | return 0; |
| 421 | last = buf; |
| 422 | } |
| 423 | return last; |
| 424 | } |
| 425 | |
| 426 | /* Called before calling _bfd_elf_parse_eh_frame on every input bfd's |
| 427 | .eh_frame section. */ |
| 428 | |
| 429 | void |
| 430 | _bfd_elf_begin_eh_frame_parsing (struct bfd_link_info *info) |
| 431 | { |
| 432 | struct eh_frame_hdr_info *hdr_info; |
| 433 | |
| 434 | hdr_info = &elf_hash_table (info)->eh_info; |
| 435 | hdr_info->merge_cies = !info->relocatable; |
| 436 | } |
| 437 | |
| 438 | /* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the |
| 439 | information in the section's sec_info field on success. COOKIE |
| 440 | describes the relocations in SEC. */ |
| 441 | |
| 442 | void |
| 443 | _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info, |
| 444 | asection *sec, struct elf_reloc_cookie *cookie) |
| 445 | { |
| 446 | #define REQUIRE(COND) \ |
| 447 | do \ |
| 448 | if (!(COND)) \ |
| 449 | goto free_no_table; \ |
| 450 | while (0) |
| 451 | |
| 452 | bfd_byte *ehbuf = NULL, *buf, *end; |
| 453 | bfd_byte *last_fde; |
| 454 | struct eh_cie_fde *this_inf; |
| 455 | unsigned int hdr_length, hdr_id; |
| 456 | unsigned int cie_count; |
| 457 | struct cie *cie, *local_cies = NULL; |
| 458 | struct elf_link_hash_table *htab; |
| 459 | struct eh_frame_hdr_info *hdr_info; |
| 460 | struct eh_frame_sec_info *sec_info = NULL; |
| 461 | unsigned int ptr_size; |
| 462 | unsigned int num_cies; |
| 463 | unsigned int num_entries; |
| 464 | elf_gc_mark_hook_fn gc_mark_hook; |
| 465 | |
| 466 | htab = elf_hash_table (info); |
| 467 | hdr_info = &htab->eh_info; |
| 468 | if (hdr_info->parsed_eh_frames) |
| 469 | return; |
| 470 | |
| 471 | if (sec->size == 0) |
| 472 | { |
| 473 | /* This file does not contain .eh_frame information. */ |
| 474 | return; |
| 475 | } |
| 476 | |
| 477 | if (bfd_is_abs_section (sec->output_section)) |
| 478 | { |
| 479 | /* At least one of the sections is being discarded from the |
| 480 | link, so we should just ignore them. */ |
| 481 | return; |
| 482 | } |
| 483 | |
| 484 | /* Read the frame unwind information from abfd. */ |
| 485 | |
| 486 | REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf)); |
| 487 | |
| 488 | if (sec->size >= 4 |
| 489 | && bfd_get_32 (abfd, ehbuf) == 0 |
| 490 | && cookie->rel == cookie->relend) |
| 491 | { |
| 492 | /* Empty .eh_frame section. */ |
| 493 | free (ehbuf); |
| 494 | return; |
| 495 | } |
| 496 | |
| 497 | /* If .eh_frame section size doesn't fit into int, we cannot handle |
| 498 | it (it would need to use 64-bit .eh_frame format anyway). */ |
| 499 | REQUIRE (sec->size == (unsigned int) sec->size); |
| 500 | |
| 501 | ptr_size = (get_elf_backend_data (abfd) |
| 502 | ->elf_backend_eh_frame_address_size (abfd, sec)); |
| 503 | REQUIRE (ptr_size != 0); |
| 504 | |
| 505 | /* Go through the section contents and work out how many FDEs and |
| 506 | CIEs there are. */ |
| 507 | buf = ehbuf; |
| 508 | end = ehbuf + sec->size; |
| 509 | num_cies = 0; |
| 510 | num_entries = 0; |
| 511 | while (buf != end) |
| 512 | { |
| 513 | num_entries++; |
| 514 | |
| 515 | /* Read the length of the entry. */ |
| 516 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 517 | hdr_length = bfd_get_32 (abfd, buf - 4); |
| 518 | |
| 519 | /* 64-bit .eh_frame is not supported. */ |
| 520 | REQUIRE (hdr_length != 0xffffffff); |
| 521 | if (hdr_length == 0) |
| 522 | break; |
| 523 | |
| 524 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 525 | hdr_id = bfd_get_32 (abfd, buf - 4); |
| 526 | if (hdr_id == 0) |
| 527 | num_cies++; |
| 528 | |
| 529 | REQUIRE (skip_bytes (&buf, end, hdr_length - 4)); |
| 530 | } |
| 531 | |
| 532 | sec_info = bfd_zmalloc (sizeof (struct eh_frame_sec_info) |
| 533 | + (num_entries - 1) * sizeof (struct eh_cie_fde)); |
| 534 | REQUIRE (sec_info); |
| 535 | |
| 536 | /* We need to have a "struct cie" for each CIE in this section. */ |
| 537 | local_cies = bfd_zmalloc (num_cies * sizeof (*local_cies)); |
| 538 | REQUIRE (local_cies); |
| 539 | |
| 540 | #define ENSURE_NO_RELOCS(buf) \ |
| 541 | REQUIRE (!(cookie->rel < cookie->relend \ |
| 542 | && (cookie->rel->r_offset \ |
| 543 | < (bfd_size_type) ((buf) - ehbuf)) \ |
| 544 | && cookie->rel->r_info != 0)) |
| 545 | |
| 546 | #define SKIP_RELOCS(buf) \ |
| 547 | while (cookie->rel < cookie->relend \ |
| 548 | && (cookie->rel->r_offset \ |
| 549 | < (bfd_size_type) ((buf) - ehbuf))) \ |
| 550 | cookie->rel++ |
| 551 | |
| 552 | #define GET_RELOC(buf) \ |
| 553 | ((cookie->rel < cookie->relend \ |
| 554 | && (cookie->rel->r_offset \ |
| 555 | == (bfd_size_type) ((buf) - ehbuf))) \ |
| 556 | ? cookie->rel : NULL) |
| 557 | |
| 558 | buf = ehbuf; |
| 559 | cie_count = 0; |
| 560 | gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook; |
| 561 | while ((bfd_size_type) (buf - ehbuf) != sec->size) |
| 562 | { |
| 563 | char *aug; |
| 564 | bfd_byte *start, *insns, *insns_end; |
| 565 | bfd_size_type length; |
| 566 | unsigned int set_loc_count; |
| 567 | |
| 568 | this_inf = sec_info->entry + sec_info->count; |
| 569 | last_fde = buf; |
| 570 | |
| 571 | /* Read the length of the entry. */ |
| 572 | REQUIRE (skip_bytes (&buf, ehbuf + sec->size, 4)); |
| 573 | hdr_length = bfd_get_32 (abfd, buf - 4); |
| 574 | |
| 575 | /* The CIE/FDE must be fully contained in this input section. */ |
| 576 | REQUIRE ((bfd_size_type) (buf - ehbuf) + hdr_length <= sec->size); |
| 577 | end = buf + hdr_length; |
| 578 | |
| 579 | this_inf->offset = last_fde - ehbuf; |
| 580 | this_inf->size = 4 + hdr_length; |
| 581 | this_inf->reloc_index = cookie->rel - cookie->rels; |
| 582 | |
| 583 | if (hdr_length == 0) |
| 584 | { |
| 585 | /* A zero-length CIE should only be found at the end of |
| 586 | the section. */ |
| 587 | REQUIRE ((bfd_size_type) (buf - ehbuf) == sec->size); |
| 588 | ENSURE_NO_RELOCS (buf); |
| 589 | sec_info->count++; |
| 590 | break; |
| 591 | } |
| 592 | |
| 593 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 594 | hdr_id = bfd_get_32 (abfd, buf - 4); |
| 595 | |
| 596 | if (hdr_id == 0) |
| 597 | { |
| 598 | unsigned int initial_insn_length; |
| 599 | |
| 600 | /* CIE */ |
| 601 | this_inf->cie = 1; |
| 602 | |
| 603 | /* Point CIE to one of the section-local cie structures. */ |
| 604 | cie = local_cies + cie_count++; |
| 605 | |
| 606 | cie->cie_inf = this_inf; |
| 607 | cie->length = hdr_length; |
| 608 | cie->output_sec = sec->output_section; |
| 609 | start = buf; |
| 610 | REQUIRE (read_byte (&buf, end, &cie->version)); |
| 611 | |
| 612 | /* Cannot handle unknown versions. */ |
| 613 | REQUIRE (cie->version == 1 || cie->version == 3); |
| 614 | REQUIRE (strlen ((char *) buf) < sizeof (cie->augmentation)); |
| 615 | |
| 616 | strcpy (cie->augmentation, (char *) buf); |
| 617 | buf = (bfd_byte *) strchr ((char *) buf, '\0') + 1; |
| 618 | ENSURE_NO_RELOCS (buf); |
| 619 | if (buf[0] == 'e' && buf[1] == 'h') |
| 620 | { |
| 621 | /* GCC < 3.0 .eh_frame CIE */ |
| 622 | /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__ |
| 623 | is private to each CIE, so we don't need it for anything. |
| 624 | Just skip it. */ |
| 625 | REQUIRE (skip_bytes (&buf, end, ptr_size)); |
| 626 | SKIP_RELOCS (buf); |
| 627 | } |
| 628 | REQUIRE (read_uleb128 (&buf, end, &cie->code_align)); |
| 629 | REQUIRE (read_sleb128 (&buf, end, &cie->data_align)); |
| 630 | if (cie->version == 1) |
| 631 | { |
| 632 | REQUIRE (buf < end); |
| 633 | cie->ra_column = *buf++; |
| 634 | } |
| 635 | else |
| 636 | REQUIRE (read_uleb128 (&buf, end, &cie->ra_column)); |
| 637 | ENSURE_NO_RELOCS (buf); |
| 638 | cie->lsda_encoding = DW_EH_PE_omit; |
| 639 | cie->fde_encoding = DW_EH_PE_omit; |
| 640 | cie->per_encoding = DW_EH_PE_omit; |
| 641 | aug = cie->augmentation; |
| 642 | if (aug[0] != 'e' || aug[1] != 'h') |
| 643 | { |
| 644 | if (*aug == 'z') |
| 645 | { |
| 646 | aug++; |
| 647 | REQUIRE (read_uleb128 (&buf, end, &cie->augmentation_size)); |
| 648 | ENSURE_NO_RELOCS (buf); |
| 649 | } |
| 650 | |
| 651 | while (*aug != '\0') |
| 652 | switch (*aug++) |
| 653 | { |
| 654 | case 'L': |
| 655 | REQUIRE (read_byte (&buf, end, &cie->lsda_encoding)); |
| 656 | ENSURE_NO_RELOCS (buf); |
| 657 | REQUIRE (get_DW_EH_PE_width (cie->lsda_encoding, ptr_size)); |
| 658 | break; |
| 659 | case 'R': |
| 660 | REQUIRE (read_byte (&buf, end, &cie->fde_encoding)); |
| 661 | ENSURE_NO_RELOCS (buf); |
| 662 | REQUIRE (get_DW_EH_PE_width (cie->fde_encoding, ptr_size)); |
| 663 | break; |
| 664 | case 'S': |
| 665 | break; |
| 666 | case 'P': |
| 667 | { |
| 668 | int per_width; |
| 669 | |
| 670 | REQUIRE (read_byte (&buf, end, &cie->per_encoding)); |
| 671 | per_width = get_DW_EH_PE_width (cie->per_encoding, |
| 672 | ptr_size); |
| 673 | REQUIRE (per_width); |
| 674 | if ((cie->per_encoding & 0xf0) == DW_EH_PE_aligned) |
| 675 | { |
| 676 | length = -(buf - ehbuf) & (per_width - 1); |
| 677 | REQUIRE (skip_bytes (&buf, end, length)); |
| 678 | } |
| 679 | ENSURE_NO_RELOCS (buf); |
| 680 | /* Ensure we have a reloc here. */ |
| 681 | REQUIRE (GET_RELOC (buf)); |
| 682 | cie->personality.reloc_index |
| 683 | = cookie->rel - cookie->rels; |
| 684 | /* Cope with MIPS-style composite relocations. */ |
| 685 | do |
| 686 | cookie->rel++; |
| 687 | while (GET_RELOC (buf) != NULL); |
| 688 | REQUIRE (skip_bytes (&buf, end, per_width)); |
| 689 | } |
| 690 | break; |
| 691 | default: |
| 692 | /* Unrecognized augmentation. Better bail out. */ |
| 693 | goto free_no_table; |
| 694 | } |
| 695 | } |
| 696 | |
| 697 | /* For shared libraries, try to get rid of as many RELATIVE relocs |
| 698 | as possible. */ |
| 699 | if (info->shared |
| 700 | && (get_elf_backend_data (abfd) |
| 701 | ->elf_backend_can_make_relative_eh_frame |
| 702 | (abfd, info, sec))) |
| 703 | { |
| 704 | if ((cie->fde_encoding & 0xf0) == DW_EH_PE_absptr) |
| 705 | this_inf->make_relative = 1; |
| 706 | /* If the CIE doesn't already have an 'R' entry, it's fairly |
| 707 | easy to add one, provided that there's no aligned data |
| 708 | after the augmentation string. */ |
| 709 | else if (cie->fde_encoding == DW_EH_PE_omit |
| 710 | && (cie->per_encoding & 0xf0) != DW_EH_PE_aligned) |
| 711 | { |
| 712 | if (*cie->augmentation == 0) |
| 713 | this_inf->add_augmentation_size = 1; |
| 714 | this_inf->u.cie.add_fde_encoding = 1; |
| 715 | this_inf->make_relative = 1; |
| 716 | } |
| 717 | } |
| 718 | |
| 719 | if (info->shared |
| 720 | && (get_elf_backend_data (abfd) |
| 721 | ->elf_backend_can_make_lsda_relative_eh_frame |
| 722 | (abfd, info, sec)) |
| 723 | && (cie->lsda_encoding & 0xf0) == DW_EH_PE_absptr) |
| 724 | cie->can_make_lsda_relative = 1; |
| 725 | |
| 726 | /* If FDE encoding was not specified, it defaults to |
| 727 | DW_EH_absptr. */ |
| 728 | if (cie->fde_encoding == DW_EH_PE_omit) |
| 729 | cie->fde_encoding = DW_EH_PE_absptr; |
| 730 | |
| 731 | initial_insn_length = end - buf; |
| 732 | if (initial_insn_length <= sizeof (cie->initial_instructions)) |
| 733 | { |
| 734 | cie->initial_insn_length = initial_insn_length; |
| 735 | memcpy (cie->initial_instructions, buf, initial_insn_length); |
| 736 | } |
| 737 | insns = buf; |
| 738 | buf += initial_insn_length; |
| 739 | ENSURE_NO_RELOCS (buf); |
| 740 | |
| 741 | if (hdr_info->merge_cies) |
| 742 | this_inf->u.cie.u.full_cie = cie; |
| 743 | this_inf->u.cie.per_encoding_relative |
| 744 | = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel; |
| 745 | } |
| 746 | else |
| 747 | { |
| 748 | asection *rsec; |
| 749 | |
| 750 | /* Find the corresponding CIE. */ |
| 751 | unsigned int cie_offset = this_inf->offset + 4 - hdr_id; |
| 752 | for (cie = local_cies; cie < local_cies + cie_count; cie++) |
| 753 | if (cie_offset == cie->cie_inf->offset) |
| 754 | break; |
| 755 | |
| 756 | /* Ensure this FDE references one of the CIEs in this input |
| 757 | section. */ |
| 758 | REQUIRE (cie != local_cies + cie_count); |
| 759 | this_inf->u.fde.cie_inf = cie->cie_inf; |
| 760 | this_inf->make_relative = cie->cie_inf->make_relative; |
| 761 | this_inf->add_augmentation_size |
| 762 | = cie->cie_inf->add_augmentation_size; |
| 763 | |
| 764 | ENSURE_NO_RELOCS (buf); |
| 765 | REQUIRE (GET_RELOC (buf)); |
| 766 | |
| 767 | /* Chain together the FDEs for each section. */ |
| 768 | rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie); |
| 769 | REQUIRE (rsec && rsec->owner == abfd); |
| 770 | this_inf->u.fde.next_for_section = elf_fde_list (rsec); |
| 771 | elf_fde_list (rsec) = this_inf; |
| 772 | |
| 773 | /* Skip the initial location and address range. */ |
| 774 | start = buf; |
| 775 | length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); |
| 776 | REQUIRE (skip_bytes (&buf, end, 2 * length)); |
| 777 | |
| 778 | /* Skip the augmentation size, if present. */ |
| 779 | if (cie->augmentation[0] == 'z') |
| 780 | REQUIRE (read_uleb128 (&buf, end, &length)); |
| 781 | else |
| 782 | length = 0; |
| 783 | |
| 784 | /* Of the supported augmentation characters above, only 'L' |
| 785 | adds augmentation data to the FDE. This code would need to |
| 786 | be adjusted if any future augmentations do the same thing. */ |
| 787 | if (cie->lsda_encoding != DW_EH_PE_omit) |
| 788 | { |
| 789 | SKIP_RELOCS (buf); |
| 790 | if (cie->can_make_lsda_relative && GET_RELOC (buf)) |
| 791 | cie->cie_inf->u.cie.make_lsda_relative = 1; |
| 792 | this_inf->lsda_offset = buf - start; |
| 793 | /* If there's no 'z' augmentation, we don't know where the |
| 794 | CFA insns begin. Assume no padding. */ |
| 795 | if (cie->augmentation[0] != 'z') |
| 796 | length = end - buf; |
| 797 | } |
| 798 | |
| 799 | /* Skip over the augmentation data. */ |
| 800 | REQUIRE (skip_bytes (&buf, end, length)); |
| 801 | insns = buf; |
| 802 | |
| 803 | buf = last_fde + 4 + hdr_length; |
| 804 | SKIP_RELOCS (buf); |
| 805 | } |
| 806 | |
| 807 | /* Try to interpret the CFA instructions and find the first |
| 808 | padding nop. Shrink this_inf's size so that it doesn't |
| 809 | include the padding. */ |
| 810 | length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); |
| 811 | set_loc_count = 0; |
| 812 | insns_end = skip_non_nops (insns, end, length, &set_loc_count); |
| 813 | /* If we don't understand the CFA instructions, we can't know |
| 814 | what needs to be adjusted there. */ |
| 815 | if (insns_end == NULL |
| 816 | /* For the time being we don't support DW_CFA_set_loc in |
| 817 | CIE instructions. */ |
| 818 | || (set_loc_count && this_inf->cie)) |
| 819 | goto free_no_table; |
| 820 | this_inf->size -= end - insns_end; |
| 821 | if (insns_end != end && this_inf->cie) |
| 822 | { |
| 823 | cie->initial_insn_length -= end - insns_end; |
| 824 | cie->length -= end - insns_end; |
| 825 | } |
| 826 | if (set_loc_count |
| 827 | && ((cie->fde_encoding & 0xf0) == DW_EH_PE_pcrel |
| 828 | || this_inf->make_relative)) |
| 829 | { |
| 830 | unsigned int cnt; |
| 831 | bfd_byte *p; |
| 832 | |
| 833 | this_inf->set_loc = bfd_malloc ((set_loc_count + 1) |
| 834 | * sizeof (unsigned int)); |
| 835 | REQUIRE (this_inf->set_loc); |
| 836 | this_inf->set_loc[0] = set_loc_count; |
| 837 | p = insns; |
| 838 | cnt = 0; |
| 839 | while (p < end) |
| 840 | { |
| 841 | if (*p == DW_CFA_set_loc) |
| 842 | this_inf->set_loc[++cnt] = p + 1 - start; |
| 843 | REQUIRE (skip_cfa_op (&p, end, length)); |
| 844 | } |
| 845 | } |
| 846 | |
| 847 | this_inf->removed = 1; |
| 848 | this_inf->fde_encoding = cie->fde_encoding; |
| 849 | this_inf->lsda_encoding = cie->lsda_encoding; |
| 850 | sec_info->count++; |
| 851 | } |
| 852 | BFD_ASSERT (sec_info->count == num_entries); |
| 853 | BFD_ASSERT (cie_count == num_cies); |
| 854 | |
| 855 | elf_section_data (sec)->sec_info = sec_info; |
| 856 | sec->sec_info_type = ELF_INFO_TYPE_EH_FRAME; |
| 857 | if (hdr_info->merge_cies) |
| 858 | { |
| 859 | sec_info->cies = local_cies; |
| 860 | local_cies = NULL; |
| 861 | } |
| 862 | goto success; |
| 863 | |
| 864 | free_no_table: |
| 865 | (*info->callbacks->einfo) |
| 866 | (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"), |
| 867 | abfd, sec); |
| 868 | hdr_info->table = FALSE; |
| 869 | if (sec_info) |
| 870 | free (sec_info); |
| 871 | success: |
| 872 | if (ehbuf) |
| 873 | free (ehbuf); |
| 874 | if (local_cies) |
| 875 | free (local_cies); |
| 876 | #undef REQUIRE |
| 877 | } |
| 878 | |
| 879 | /* Finish a pass over all .eh_frame sections. */ |
| 880 | |
| 881 | void |
| 882 | _bfd_elf_end_eh_frame_parsing (struct bfd_link_info *info) |
| 883 | { |
| 884 | struct eh_frame_hdr_info *hdr_info; |
| 885 | |
| 886 | hdr_info = &elf_hash_table (info)->eh_info; |
| 887 | hdr_info->parsed_eh_frames = TRUE; |
| 888 | } |
| 889 | |
| 890 | /* Mark all relocations against CIE or FDE ENT, which occurs in |
| 891 | .eh_frame section SEC. COOKIE describes the relocations in SEC; |
| 892 | its "rel" field can be changed freely. */ |
| 893 | |
| 894 | static bfd_boolean |
| 895 | mark_entry (struct bfd_link_info *info, asection *sec, |
| 896 | struct eh_cie_fde *ent, elf_gc_mark_hook_fn gc_mark_hook, |
| 897 | struct elf_reloc_cookie *cookie) |
| 898 | { |
| 899 | for (cookie->rel = cookie->rels + ent->reloc_index; |
| 900 | cookie->rel < cookie->relend |
| 901 | && cookie->rel->r_offset < ent->offset + ent->size; |
| 902 | cookie->rel++) |
| 903 | if (!_bfd_elf_gc_mark_reloc (info, sec, gc_mark_hook, cookie)) |
| 904 | return FALSE; |
| 905 | |
| 906 | return TRUE; |
| 907 | } |
| 908 | |
| 909 | /* Mark all the relocations against FDEs that relate to code in input |
| 910 | section SEC. The FDEs belong to .eh_frame section EH_FRAME, whose |
| 911 | relocations are described by COOKIE. */ |
| 912 | |
| 913 | bfd_boolean |
| 914 | _bfd_elf_gc_mark_fdes (struct bfd_link_info *info, asection *sec, |
| 915 | asection *eh_frame, elf_gc_mark_hook_fn gc_mark_hook, |
| 916 | struct elf_reloc_cookie *cookie) |
| 917 | { |
| 918 | struct eh_cie_fde *fde, *cie; |
| 919 | |
| 920 | for (fde = elf_fde_list (sec); fde; fde = fde->u.fde.next_for_section) |
| 921 | { |
| 922 | if (!mark_entry (info, eh_frame, fde, gc_mark_hook, cookie)) |
| 923 | return FALSE; |
| 924 | |
| 925 | /* At this stage, all cie_inf fields point to local CIEs, so we |
| 926 | can use the same cookie to refer to them. */ |
| 927 | cie = fde->u.fde.cie_inf; |
| 928 | if (!cie->u.cie.gc_mark) |
| 929 | { |
| 930 | cie->u.cie.gc_mark = 1; |
| 931 | if (!mark_entry (info, eh_frame, cie, gc_mark_hook, cookie)) |
| 932 | return FALSE; |
| 933 | } |
| 934 | } |
| 935 | return TRUE; |
| 936 | } |
| 937 | |
| 938 | /* Input section SEC of ABFD is an .eh_frame section that contains the |
| 939 | CIE described by CIE_INF. Return a version of CIE_INF that is going |
| 940 | to be kept in the output, adding CIE_INF to the output if necessary. |
| 941 | |
| 942 | HDR_INFO is the .eh_frame_hdr information and COOKIE describes the |
| 943 | relocations in REL. */ |
| 944 | |
| 945 | static struct eh_cie_fde * |
| 946 | find_merged_cie (bfd *abfd, asection *sec, |
| 947 | struct eh_frame_hdr_info *hdr_info, |
| 948 | struct elf_reloc_cookie *cookie, |
| 949 | struct eh_cie_fde *cie_inf) |
| 950 | { |
| 951 | unsigned long r_symndx; |
| 952 | struct cie *cie, *new_cie; |
| 953 | Elf_Internal_Rela *rel; |
| 954 | void **loc; |
| 955 | |
| 956 | /* Use CIE_INF if we have already decided to keep it. */ |
| 957 | if (!cie_inf->removed) |
| 958 | return cie_inf; |
| 959 | |
| 960 | /* If we have merged CIE_INF with another CIE, use that CIE instead. */ |
| 961 | if (cie_inf->u.cie.merged) |
| 962 | return cie_inf->u.cie.u.merged_with; |
| 963 | |
| 964 | cie = cie_inf->u.cie.u.full_cie; |
| 965 | |
| 966 | /* Assume we will need to keep CIE_INF. */ |
| 967 | cie_inf->removed = 0; |
| 968 | cie_inf->u.cie.u.sec = sec; |
| 969 | |
| 970 | /* If we are not merging CIEs, use CIE_INF. */ |
| 971 | if (cie == NULL) |
| 972 | return cie_inf; |
| 973 | |
| 974 | if (cie->per_encoding != DW_EH_PE_omit) |
| 975 | { |
| 976 | /* Work out the address of personality routine, either as an absolute |
| 977 | value or as a symbol. */ |
| 978 | rel = cookie->rels + cie->personality.reloc_index; |
| 979 | memset (&cie->personality, 0, sizeof (cie->personality)); |
| 980 | #ifdef BFD64 |
| 981 | if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64) |
| 982 | r_symndx = ELF64_R_SYM (rel->r_info); |
| 983 | else |
| 984 | #endif |
| 985 | r_symndx = ELF32_R_SYM (rel->r_info); |
| 986 | if (r_symndx >= cookie->locsymcount |
| 987 | || ELF_ST_BIND (cookie->locsyms[r_symndx].st_info) != STB_LOCAL) |
| 988 | { |
| 989 | struct elf_link_hash_entry *h; |
| 990 | |
| 991 | r_symndx -= cookie->extsymoff; |
| 992 | h = cookie->sym_hashes[r_symndx]; |
| 993 | |
| 994 | while (h->root.type == bfd_link_hash_indirect |
| 995 | || h->root.type == bfd_link_hash_warning) |
| 996 | h = (struct elf_link_hash_entry *) h->root.u.i.link; |
| 997 | |
| 998 | cie->personality.h = h; |
| 999 | } |
| 1000 | else |
| 1001 | { |
| 1002 | Elf_Internal_Sym *sym; |
| 1003 | asection *sym_sec; |
| 1004 | |
| 1005 | sym = &cookie->locsyms[r_symndx]; |
| 1006 | sym_sec = bfd_section_from_elf_index (abfd, sym->st_shndx); |
| 1007 | if (sym_sec == NULL) |
| 1008 | return cie_inf; |
| 1009 | |
| 1010 | if (sym_sec->kept_section != NULL) |
| 1011 | sym_sec = sym_sec->kept_section; |
| 1012 | if (sym_sec->output_section == NULL) |
| 1013 | return cie_inf; |
| 1014 | |
| 1015 | cie->local_personality = 1; |
| 1016 | cie->personality.val = (sym->st_value |
| 1017 | + sym_sec->output_offset |
| 1018 | + sym_sec->output_section->vma); |
| 1019 | } |
| 1020 | } |
| 1021 | |
| 1022 | /* See if we can merge this CIE with an earlier one. */ |
| 1023 | cie->output_sec = sec->output_section; |
| 1024 | cie_compute_hash (cie); |
| 1025 | if (hdr_info->cies == NULL) |
| 1026 | { |
| 1027 | hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free); |
| 1028 | if (hdr_info->cies == NULL) |
| 1029 | return cie_inf; |
| 1030 | } |
| 1031 | loc = htab_find_slot_with_hash (hdr_info->cies, cie, cie->hash, INSERT); |
| 1032 | if (loc == NULL) |
| 1033 | return cie_inf; |
| 1034 | |
| 1035 | new_cie = (struct cie *) *loc; |
| 1036 | if (new_cie == NULL) |
| 1037 | { |
| 1038 | /* Keep CIE_INF and record it in the hash table. */ |
| 1039 | new_cie = malloc (sizeof (struct cie)); |
| 1040 | if (new_cie == NULL) |
| 1041 | return cie_inf; |
| 1042 | |
| 1043 | memcpy (new_cie, cie, sizeof (struct cie)); |
| 1044 | *loc = new_cie; |
| 1045 | } |
| 1046 | else |
| 1047 | { |
| 1048 | /* Merge CIE_INF with NEW_CIE->CIE_INF. */ |
| 1049 | cie_inf->removed = 1; |
| 1050 | cie_inf->u.cie.merged = 1; |
| 1051 | cie_inf->u.cie.u.merged_with = new_cie->cie_inf; |
| 1052 | if (cie_inf->u.cie.make_lsda_relative) |
| 1053 | new_cie->cie_inf->u.cie.make_lsda_relative = 1; |
| 1054 | } |
| 1055 | return new_cie->cie_inf; |
| 1056 | } |
| 1057 | |
| 1058 | /* This function is called for each input file before the .eh_frame |
| 1059 | section is relocated. It discards duplicate CIEs and FDEs for discarded |
| 1060 | functions. The function returns TRUE iff any entries have been |
| 1061 | deleted. */ |
| 1062 | |
| 1063 | bfd_boolean |
| 1064 | _bfd_elf_discard_section_eh_frame |
| 1065 | (bfd *abfd, struct bfd_link_info *info, asection *sec, |
| 1066 | bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *), |
| 1067 | struct elf_reloc_cookie *cookie) |
| 1068 | { |
| 1069 | struct eh_cie_fde *ent; |
| 1070 | struct eh_frame_sec_info *sec_info; |
| 1071 | struct eh_frame_hdr_info *hdr_info; |
| 1072 | unsigned int ptr_size, offset; |
| 1073 | |
| 1074 | sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; |
| 1075 | if (sec_info == NULL) |
| 1076 | return FALSE; |
| 1077 | |
| 1078 | hdr_info = &elf_hash_table (info)->eh_info; |
| 1079 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1080 | if (ent->size == 4) |
| 1081 | /* There should only be one zero terminator, on the last input |
| 1082 | file supplying .eh_frame (crtend.o). Remove any others. */ |
| 1083 | ent->removed = sec->map_head.s != NULL; |
| 1084 | else if (!ent->cie) |
| 1085 | { |
| 1086 | cookie->rel = cookie->rels + ent->reloc_index; |
| 1087 | BFD_ASSERT (cookie->rel < cookie->relend |
| 1088 | && cookie->rel->r_offset == ent->offset + 8); |
| 1089 | if (!(*reloc_symbol_deleted_p) (ent->offset + 8, cookie)) |
| 1090 | { |
| 1091 | if (info->shared |
| 1092 | && (((ent->fde_encoding & 0xf0) == DW_EH_PE_absptr |
| 1093 | && ent->make_relative == 0) |
| 1094 | || (ent->fde_encoding & 0xf0) == DW_EH_PE_aligned)) |
| 1095 | { |
| 1096 | /* If a shared library uses absolute pointers |
| 1097 | which we cannot turn into PC relative, |
| 1098 | don't create the binary search table, |
| 1099 | since it is affected by runtime relocations. */ |
| 1100 | hdr_info->table = FALSE; |
| 1101 | (*info->callbacks->einfo) |
| 1102 | (_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr" |
| 1103 | " table being created.\n"), abfd, sec); |
| 1104 | } |
| 1105 | ent->removed = 0; |
| 1106 | hdr_info->fde_count++; |
| 1107 | ent->u.fde.cie_inf = find_merged_cie (abfd, sec, hdr_info, cookie, |
| 1108 | ent->u.fde.cie_inf); |
| 1109 | } |
| 1110 | } |
| 1111 | |
| 1112 | if (sec_info->cies) |
| 1113 | { |
| 1114 | free (sec_info->cies); |
| 1115 | sec_info->cies = NULL; |
| 1116 | } |
| 1117 | |
| 1118 | ptr_size = (get_elf_backend_data (sec->owner) |
| 1119 | ->elf_backend_eh_frame_address_size (sec->owner, sec)); |
| 1120 | offset = 0; |
| 1121 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1122 | if (!ent->removed) |
| 1123 | { |
| 1124 | ent->new_offset = offset; |
| 1125 | offset += size_of_output_cie_fde (ent, ptr_size); |
| 1126 | } |
| 1127 | |
| 1128 | sec->rawsize = sec->size; |
| 1129 | sec->size = offset; |
| 1130 | return offset != sec->rawsize; |
| 1131 | } |
| 1132 | |
| 1133 | /* This function is called for .eh_frame_hdr section after |
| 1134 | _bfd_elf_discard_section_eh_frame has been called on all .eh_frame |
| 1135 | input sections. It finalizes the size of .eh_frame_hdr section. */ |
| 1136 | |
| 1137 | bfd_boolean |
| 1138 | _bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 1139 | { |
| 1140 | struct elf_link_hash_table *htab; |
| 1141 | struct eh_frame_hdr_info *hdr_info; |
| 1142 | asection *sec; |
| 1143 | |
| 1144 | htab = elf_hash_table (info); |
| 1145 | hdr_info = &htab->eh_info; |
| 1146 | |
| 1147 | if (hdr_info->cies != NULL) |
| 1148 | { |
| 1149 | htab_delete (hdr_info->cies); |
| 1150 | hdr_info->cies = NULL; |
| 1151 | } |
| 1152 | |
| 1153 | sec = hdr_info->hdr_sec; |
| 1154 | if (sec == NULL) |
| 1155 | return FALSE; |
| 1156 | |
| 1157 | sec->size = EH_FRAME_HDR_SIZE; |
| 1158 | if (hdr_info->table) |
| 1159 | sec->size += 4 + hdr_info->fde_count * 8; |
| 1160 | |
| 1161 | elf_tdata (abfd)->eh_frame_hdr = sec; |
| 1162 | return TRUE; |
| 1163 | } |
| 1164 | |
| 1165 | /* This function is called from size_dynamic_sections. |
| 1166 | It needs to decide whether .eh_frame_hdr should be output or not, |
| 1167 | because when the dynamic symbol table has been sized it is too late |
| 1168 | to strip sections. */ |
| 1169 | |
| 1170 | bfd_boolean |
| 1171 | _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info) |
| 1172 | { |
| 1173 | asection *o; |
| 1174 | bfd *abfd; |
| 1175 | struct elf_link_hash_table *htab; |
| 1176 | struct eh_frame_hdr_info *hdr_info; |
| 1177 | |
| 1178 | htab = elf_hash_table (info); |
| 1179 | hdr_info = &htab->eh_info; |
| 1180 | if (hdr_info->hdr_sec == NULL) |
| 1181 | return TRUE; |
| 1182 | |
| 1183 | if (bfd_is_abs_section (hdr_info->hdr_sec->output_section)) |
| 1184 | { |
| 1185 | hdr_info->hdr_sec = NULL; |
| 1186 | return TRUE; |
| 1187 | } |
| 1188 | |
| 1189 | abfd = NULL; |
| 1190 | if (info->eh_frame_hdr) |
| 1191 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) |
| 1192 | { |
| 1193 | /* Count only sections which have at least a single CIE or FDE. |
| 1194 | There cannot be any CIE or FDE <= 8 bytes. */ |
| 1195 | o = bfd_get_section_by_name (abfd, ".eh_frame"); |
| 1196 | if (o && o->size > 8 && !bfd_is_abs_section (o->output_section)) |
| 1197 | break; |
| 1198 | } |
| 1199 | |
| 1200 | if (abfd == NULL) |
| 1201 | { |
| 1202 | hdr_info->hdr_sec->flags |= SEC_EXCLUDE; |
| 1203 | hdr_info->hdr_sec = NULL; |
| 1204 | return TRUE; |
| 1205 | } |
| 1206 | |
| 1207 | hdr_info->table = TRUE; |
| 1208 | return TRUE; |
| 1209 | } |
| 1210 | |
| 1211 | /* Adjust an address in the .eh_frame section. Given OFFSET within |
| 1212 | SEC, this returns the new offset in the adjusted .eh_frame section, |
| 1213 | or -1 if the address refers to a CIE/FDE which has been removed |
| 1214 | or to offset with dynamic relocation which is no longer needed. */ |
| 1215 | |
| 1216 | bfd_vma |
| 1217 | _bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, |
| 1218 | struct bfd_link_info *info, |
| 1219 | asection *sec, |
| 1220 | bfd_vma offset) |
| 1221 | { |
| 1222 | struct eh_frame_sec_info *sec_info; |
| 1223 | struct elf_link_hash_table *htab; |
| 1224 | struct eh_frame_hdr_info *hdr_info; |
| 1225 | unsigned int lo, hi, mid; |
| 1226 | |
| 1227 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 1228 | return offset; |
| 1229 | sec_info = elf_section_data (sec)->sec_info; |
| 1230 | |
| 1231 | if (offset >= sec->rawsize) |
| 1232 | return offset - sec->rawsize + sec->size; |
| 1233 | |
| 1234 | htab = elf_hash_table (info); |
| 1235 | hdr_info = &htab->eh_info; |
| 1236 | |
| 1237 | lo = 0; |
| 1238 | hi = sec_info->count; |
| 1239 | mid = 0; |
| 1240 | while (lo < hi) |
| 1241 | { |
| 1242 | mid = (lo + hi) / 2; |
| 1243 | if (offset < sec_info->entry[mid].offset) |
| 1244 | hi = mid; |
| 1245 | else if (offset |
| 1246 | >= sec_info->entry[mid].offset + sec_info->entry[mid].size) |
| 1247 | lo = mid + 1; |
| 1248 | else |
| 1249 | break; |
| 1250 | } |
| 1251 | |
| 1252 | BFD_ASSERT (lo < hi); |
| 1253 | |
| 1254 | /* FDE or CIE was removed. */ |
| 1255 | if (sec_info->entry[mid].removed) |
| 1256 | return (bfd_vma) -1; |
| 1257 | |
| 1258 | /* If converting to DW_EH_PE_pcrel, there will be no need for run-time |
| 1259 | relocation against FDE's initial_location field. */ |
| 1260 | if (!sec_info->entry[mid].cie |
| 1261 | && sec_info->entry[mid].make_relative |
| 1262 | && offset == sec_info->entry[mid].offset + 8) |
| 1263 | return (bfd_vma) -2; |
| 1264 | |
| 1265 | /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need |
| 1266 | for run-time relocation against LSDA field. */ |
| 1267 | if (!sec_info->entry[mid].cie |
| 1268 | && sec_info->entry[mid].u.fde.cie_inf->u.cie.make_lsda_relative |
| 1269 | && offset == (sec_info->entry[mid].offset + 8 |
| 1270 | + sec_info->entry[mid].lsda_offset)) |
| 1271 | return (bfd_vma) -2; |
| 1272 | |
| 1273 | /* If converting to DW_EH_PE_pcrel, there will be no need for run-time |
| 1274 | relocation against DW_CFA_set_loc's arguments. */ |
| 1275 | if (sec_info->entry[mid].set_loc |
| 1276 | && sec_info->entry[mid].make_relative |
| 1277 | && (offset >= sec_info->entry[mid].offset + 8 |
| 1278 | + sec_info->entry[mid].set_loc[1])) |
| 1279 | { |
| 1280 | unsigned int cnt; |
| 1281 | |
| 1282 | for (cnt = 1; cnt <= sec_info->entry[mid].set_loc[0]; cnt++) |
| 1283 | if (offset == sec_info->entry[mid].offset + 8 |
| 1284 | + sec_info->entry[mid].set_loc[cnt]) |
| 1285 | return (bfd_vma) -2; |
| 1286 | } |
| 1287 | |
| 1288 | /* Any new augmentation bytes go before the first relocation. */ |
| 1289 | return (offset + sec_info->entry[mid].new_offset |
| 1290 | - sec_info->entry[mid].offset |
| 1291 | + extra_augmentation_string_bytes (sec_info->entry + mid) |
| 1292 | + extra_augmentation_data_bytes (sec_info->entry + mid)); |
| 1293 | } |
| 1294 | |
| 1295 | /* Write out .eh_frame section. This is called with the relocated |
| 1296 | contents. */ |
| 1297 | |
| 1298 | bfd_boolean |
| 1299 | _bfd_elf_write_section_eh_frame (bfd *abfd, |
| 1300 | struct bfd_link_info *info, |
| 1301 | asection *sec, |
| 1302 | bfd_byte *contents) |
| 1303 | { |
| 1304 | struct eh_frame_sec_info *sec_info; |
| 1305 | struct elf_link_hash_table *htab; |
| 1306 | struct eh_frame_hdr_info *hdr_info; |
| 1307 | unsigned int ptr_size; |
| 1308 | struct eh_cie_fde *ent; |
| 1309 | |
| 1310 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 1311 | return bfd_set_section_contents (abfd, sec->output_section, contents, |
| 1312 | sec->output_offset, sec->size); |
| 1313 | |
| 1314 | ptr_size = (get_elf_backend_data (abfd) |
| 1315 | ->elf_backend_eh_frame_address_size (abfd, sec)); |
| 1316 | BFD_ASSERT (ptr_size != 0); |
| 1317 | |
| 1318 | sec_info = elf_section_data (sec)->sec_info; |
| 1319 | htab = elf_hash_table (info); |
| 1320 | hdr_info = &htab->eh_info; |
| 1321 | |
| 1322 | if (hdr_info->table && hdr_info->array == NULL) |
| 1323 | hdr_info->array |
| 1324 | = bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array)); |
| 1325 | if (hdr_info->array == NULL) |
| 1326 | hdr_info = NULL; |
| 1327 | |
| 1328 | /* The new offsets can be bigger or smaller than the original offsets. |
| 1329 | We therefore need to make two passes over the section: one backward |
| 1330 | pass to move entries up and one forward pass to move entries down. |
| 1331 | The two passes won't interfere with each other because entries are |
| 1332 | not reordered */ |
| 1333 | for (ent = sec_info->entry + sec_info->count; ent-- != sec_info->entry;) |
| 1334 | if (!ent->removed && ent->new_offset > ent->offset) |
| 1335 | memmove (contents + ent->new_offset, contents + ent->offset, ent->size); |
| 1336 | |
| 1337 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1338 | if (!ent->removed && ent->new_offset < ent->offset) |
| 1339 | memmove (contents + ent->new_offset, contents + ent->offset, ent->size); |
| 1340 | |
| 1341 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1342 | { |
| 1343 | unsigned char *buf, *end; |
| 1344 | unsigned int new_size; |
| 1345 | |
| 1346 | if (ent->removed) |
| 1347 | continue; |
| 1348 | |
| 1349 | if (ent->size == 4) |
| 1350 | { |
| 1351 | /* Any terminating FDE must be at the end of the section. */ |
| 1352 | BFD_ASSERT (ent == sec_info->entry + sec_info->count - 1); |
| 1353 | continue; |
| 1354 | } |
| 1355 | |
| 1356 | buf = contents + ent->new_offset; |
| 1357 | end = buf + ent->size; |
| 1358 | new_size = size_of_output_cie_fde (ent, ptr_size); |
| 1359 | |
| 1360 | /* Update the size. It may be shrinked. */ |
| 1361 | bfd_put_32 (abfd, new_size - 4, buf); |
| 1362 | |
| 1363 | /* Filling the extra bytes with DW_CFA_nops. */ |
| 1364 | if (new_size != ent->size) |
| 1365 | memset (end, 0, new_size - ent->size); |
| 1366 | |
| 1367 | if (ent->cie) |
| 1368 | { |
| 1369 | /* CIE */ |
| 1370 | if (ent->make_relative |
| 1371 | || ent->u.cie.make_lsda_relative |
| 1372 | || ent->u.cie.per_encoding_relative) |
| 1373 | { |
| 1374 | char *aug; |
| 1375 | unsigned int action, extra_string, extra_data; |
| 1376 | unsigned int per_width, per_encoding; |
| 1377 | |
| 1378 | /* Need to find 'R' or 'L' augmentation's argument and modify |
| 1379 | DW_EH_PE_* value. */ |
| 1380 | action = ((ent->make_relative ? 1 : 0) |
| 1381 | | (ent->u.cie.make_lsda_relative ? 2 : 0) |
| 1382 | | (ent->u.cie.per_encoding_relative ? 4 : 0)); |
| 1383 | extra_string = extra_augmentation_string_bytes (ent); |
| 1384 | extra_data = extra_augmentation_data_bytes (ent); |
| 1385 | |
| 1386 | /* Skip length, id and version. */ |
| 1387 | buf += 9; |
| 1388 | aug = (char *) buf; |
| 1389 | buf += strlen (aug) + 1; |
| 1390 | skip_leb128 (&buf, end); |
| 1391 | skip_leb128 (&buf, end); |
| 1392 | skip_leb128 (&buf, end); |
| 1393 | if (*aug == 'z') |
| 1394 | { |
| 1395 | /* The uleb128 will always be a single byte for the kind |
| 1396 | of augmentation strings that we're prepared to handle. */ |
| 1397 | *buf++ += extra_data; |
| 1398 | aug++; |
| 1399 | } |
| 1400 | |
| 1401 | /* Make room for the new augmentation string and data bytes. */ |
| 1402 | memmove (buf + extra_string + extra_data, buf, end - buf); |
| 1403 | memmove (aug + extra_string, aug, buf - (bfd_byte *) aug); |
| 1404 | buf += extra_string; |
| 1405 | end += extra_string + extra_data; |
| 1406 | |
| 1407 | if (ent->add_augmentation_size) |
| 1408 | { |
| 1409 | *aug++ = 'z'; |
| 1410 | *buf++ = extra_data - 1; |
| 1411 | } |
| 1412 | if (ent->u.cie.add_fde_encoding) |
| 1413 | { |
| 1414 | BFD_ASSERT (action & 1); |
| 1415 | *aug++ = 'R'; |
| 1416 | *buf++ = DW_EH_PE_pcrel; |
| 1417 | action &= ~1; |
| 1418 | } |
| 1419 | |
| 1420 | while (action) |
| 1421 | switch (*aug++) |
| 1422 | { |
| 1423 | case 'L': |
| 1424 | if (action & 2) |
| 1425 | { |
| 1426 | BFD_ASSERT (*buf == ent->lsda_encoding); |
| 1427 | *buf |= DW_EH_PE_pcrel; |
| 1428 | action &= ~2; |
| 1429 | } |
| 1430 | buf++; |
| 1431 | break; |
| 1432 | case 'P': |
| 1433 | per_encoding = *buf++; |
| 1434 | per_width = get_DW_EH_PE_width (per_encoding, ptr_size); |
| 1435 | BFD_ASSERT (per_width != 0); |
| 1436 | BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel) |
| 1437 | == ent->u.cie.per_encoding_relative); |
| 1438 | if ((per_encoding & 0xf0) == DW_EH_PE_aligned) |
| 1439 | buf = (contents |
| 1440 | + ((buf - contents + per_width - 1) |
| 1441 | & ~((bfd_size_type) per_width - 1))); |
| 1442 | if (action & 4) |
| 1443 | { |
| 1444 | bfd_vma val; |
| 1445 | |
| 1446 | val = read_value (abfd, buf, per_width, |
| 1447 | get_DW_EH_PE_signed (per_encoding)); |
| 1448 | val += ent->offset - ent->new_offset; |
| 1449 | val -= extra_string + extra_data; |
| 1450 | write_value (abfd, buf, val, per_width); |
| 1451 | action &= ~4; |
| 1452 | } |
| 1453 | buf += per_width; |
| 1454 | break; |
| 1455 | case 'R': |
| 1456 | if (action & 1) |
| 1457 | { |
| 1458 | BFD_ASSERT (*buf == ent->fde_encoding); |
| 1459 | *buf |= DW_EH_PE_pcrel; |
| 1460 | action &= ~1; |
| 1461 | } |
| 1462 | buf++; |
| 1463 | break; |
| 1464 | case 'S': |
| 1465 | break; |
| 1466 | default: |
| 1467 | BFD_FAIL (); |
| 1468 | } |
| 1469 | } |
| 1470 | } |
| 1471 | else |
| 1472 | { |
| 1473 | /* FDE */ |
| 1474 | bfd_vma value, address; |
| 1475 | unsigned int width; |
| 1476 | bfd_byte *start; |
| 1477 | struct eh_cie_fde *cie; |
| 1478 | |
| 1479 | /* Skip length. */ |
| 1480 | cie = ent->u.fde.cie_inf; |
| 1481 | buf += 4; |
| 1482 | value = ((ent->new_offset + sec->output_offset + 4) |
| 1483 | - (cie->new_offset + cie->u.cie.u.sec->output_offset)); |
| 1484 | bfd_put_32 (abfd, value, buf); |
| 1485 | buf += 4; |
| 1486 | width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); |
| 1487 | value = read_value (abfd, buf, width, |
| 1488 | get_DW_EH_PE_signed (ent->fde_encoding)); |
| 1489 | address = value; |
| 1490 | if (value) |
| 1491 | { |
| 1492 | switch (ent->fde_encoding & 0xf0) |
| 1493 | { |
| 1494 | case DW_EH_PE_indirect: |
| 1495 | case DW_EH_PE_textrel: |
| 1496 | BFD_ASSERT (hdr_info == NULL); |
| 1497 | break; |
| 1498 | case DW_EH_PE_datarel: |
| 1499 | { |
| 1500 | asection *got = bfd_get_section_by_name (abfd, ".got"); |
| 1501 | |
| 1502 | BFD_ASSERT (got != NULL); |
| 1503 | address += got->vma; |
| 1504 | } |
| 1505 | break; |
| 1506 | case DW_EH_PE_pcrel: |
| 1507 | value += ent->offset - ent->new_offset; |
| 1508 | address += (sec->output_section->vma |
| 1509 | + sec->output_offset |
| 1510 | + ent->offset + 8); |
| 1511 | break; |
| 1512 | } |
| 1513 | if (ent->make_relative) |
| 1514 | value -= (sec->output_section->vma |
| 1515 | + sec->output_offset |
| 1516 | + ent->new_offset + 8); |
| 1517 | write_value (abfd, buf, value, width); |
| 1518 | } |
| 1519 | |
| 1520 | start = buf; |
| 1521 | |
| 1522 | if (hdr_info) |
| 1523 | { |
| 1524 | hdr_info->array[hdr_info->array_count].initial_loc = address; |
| 1525 | hdr_info->array[hdr_info->array_count++].fde |
| 1526 | = (sec->output_section->vma |
| 1527 | + sec->output_offset |
| 1528 | + ent->new_offset); |
| 1529 | } |
| 1530 | |
| 1531 | if ((ent->lsda_encoding & 0xf0) == DW_EH_PE_pcrel |
| 1532 | || cie->u.cie.make_lsda_relative) |
| 1533 | { |
| 1534 | buf += ent->lsda_offset; |
| 1535 | width = get_DW_EH_PE_width (ent->lsda_encoding, ptr_size); |
| 1536 | value = read_value (abfd, buf, width, |
| 1537 | get_DW_EH_PE_signed (ent->lsda_encoding)); |
| 1538 | if (value) |
| 1539 | { |
| 1540 | if ((ent->lsda_encoding & 0xf0) == DW_EH_PE_pcrel) |
| 1541 | value += ent->offset - ent->new_offset; |
| 1542 | else if (cie->u.cie.make_lsda_relative) |
| 1543 | value -= (sec->output_section->vma |
| 1544 | + sec->output_offset |
| 1545 | + ent->new_offset + 8 + ent->lsda_offset); |
| 1546 | write_value (abfd, buf, value, width); |
| 1547 | } |
| 1548 | } |
| 1549 | else if (ent->add_augmentation_size) |
| 1550 | { |
| 1551 | /* Skip the PC and length and insert a zero byte for the |
| 1552 | augmentation size. */ |
| 1553 | buf += width * 2; |
| 1554 | memmove (buf + 1, buf, end - buf); |
| 1555 | *buf = 0; |
| 1556 | } |
| 1557 | |
| 1558 | if (ent->set_loc) |
| 1559 | { |
| 1560 | /* Adjust DW_CFA_set_loc. */ |
| 1561 | unsigned int cnt, width; |
| 1562 | bfd_vma new_offset; |
| 1563 | |
| 1564 | width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); |
| 1565 | new_offset = ent->new_offset + 8 |
| 1566 | + extra_augmentation_string_bytes (ent) |
| 1567 | + extra_augmentation_data_bytes (ent); |
| 1568 | |
| 1569 | for (cnt = 1; cnt <= ent->set_loc[0]; cnt++) |
| 1570 | { |
| 1571 | bfd_vma value; |
| 1572 | buf = start + ent->set_loc[cnt]; |
| 1573 | |
| 1574 | value = read_value (abfd, buf, width, |
| 1575 | get_DW_EH_PE_signed (ent->fde_encoding)); |
| 1576 | if (!value) |
| 1577 | continue; |
| 1578 | |
| 1579 | if ((ent->fde_encoding & 0xf0) == DW_EH_PE_pcrel) |
| 1580 | value += ent->offset + 8 - new_offset; |
| 1581 | if (ent->make_relative) |
| 1582 | value -= (sec->output_section->vma |
| 1583 | + sec->output_offset |
| 1584 | + new_offset + ent->set_loc[cnt]); |
| 1585 | write_value (abfd, buf, value, width); |
| 1586 | } |
| 1587 | } |
| 1588 | } |
| 1589 | } |
| 1590 | |
| 1591 | /* We don't align the section to its section alignment since the |
| 1592 | runtime library only expects all CIE/FDE records aligned at |
| 1593 | the pointer size. _bfd_elf_discard_section_eh_frame should |
| 1594 | have padded CIE/FDE records to multiple of pointer size with |
| 1595 | size_of_output_cie_fde. */ |
| 1596 | if ((sec->size % ptr_size) != 0) |
| 1597 | abort (); |
| 1598 | |
| 1599 | return bfd_set_section_contents (abfd, sec->output_section, |
| 1600 | contents, (file_ptr) sec->output_offset, |
| 1601 | sec->size); |
| 1602 | } |
| 1603 | |
| 1604 | /* Helper function used to sort .eh_frame_hdr search table by increasing |
| 1605 | VMA of FDE initial location. */ |
| 1606 | |
| 1607 | static int |
| 1608 | vma_compare (const void *a, const void *b) |
| 1609 | { |
| 1610 | const struct eh_frame_array_ent *p = a; |
| 1611 | const struct eh_frame_array_ent *q = b; |
| 1612 | if (p->initial_loc > q->initial_loc) |
| 1613 | return 1; |
| 1614 | if (p->initial_loc < q->initial_loc) |
| 1615 | return -1; |
| 1616 | return 0; |
| 1617 | } |
| 1618 | |
| 1619 | /* Write out .eh_frame_hdr section. This must be called after |
| 1620 | _bfd_elf_write_section_eh_frame has been called on all input |
| 1621 | .eh_frame sections. |
| 1622 | .eh_frame_hdr format: |
| 1623 | ubyte version (currently 1) |
| 1624 | ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of |
| 1625 | .eh_frame section) |
| 1626 | ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count |
| 1627 | number (or DW_EH_PE_omit if there is no |
| 1628 | binary search table computed)) |
| 1629 | ubyte table_enc (DW_EH_PE_* encoding of binary search table, |
| 1630 | or DW_EH_PE_omit if not present. |
| 1631 | DW_EH_PE_datarel is using address of |
| 1632 | .eh_frame_hdr section start as base) |
| 1633 | [encoded] eh_frame_ptr (pointer to start of .eh_frame section) |
| 1634 | optionally followed by: |
| 1635 | [encoded] fde_count (total number of FDEs in .eh_frame section) |
| 1636 | fde_count x [encoded] initial_loc, fde |
| 1637 | (array of encoded pairs containing |
| 1638 | FDE initial_location field and FDE address, |
| 1639 | sorted by increasing initial_loc). */ |
| 1640 | |
| 1641 | bfd_boolean |
| 1642 | _bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 1643 | { |
| 1644 | struct elf_link_hash_table *htab; |
| 1645 | struct eh_frame_hdr_info *hdr_info; |
| 1646 | asection *sec; |
| 1647 | bfd_byte *contents; |
| 1648 | asection *eh_frame_sec; |
| 1649 | bfd_size_type size; |
| 1650 | bfd_boolean retval; |
| 1651 | bfd_vma encoded_eh_frame; |
| 1652 | |
| 1653 | htab = elf_hash_table (info); |
| 1654 | hdr_info = &htab->eh_info; |
| 1655 | sec = hdr_info->hdr_sec; |
| 1656 | if (sec == NULL) |
| 1657 | return TRUE; |
| 1658 | |
| 1659 | size = EH_FRAME_HDR_SIZE; |
| 1660 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
| 1661 | size += 4 + hdr_info->fde_count * 8; |
| 1662 | contents = bfd_malloc (size); |
| 1663 | if (contents == NULL) |
| 1664 | return FALSE; |
| 1665 | |
| 1666 | eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame"); |
| 1667 | if (eh_frame_sec == NULL) |
| 1668 | { |
| 1669 | free (contents); |
| 1670 | return FALSE; |
| 1671 | } |
| 1672 | |
| 1673 | memset (contents, 0, EH_FRAME_HDR_SIZE); |
| 1674 | contents[0] = 1; /* Version. */ |
| 1675 | contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address |
| 1676 | (abfd, info, eh_frame_sec, 0, sec, 4, |
| 1677 | &encoded_eh_frame); /* .eh_frame offset. */ |
| 1678 | |
| 1679 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
| 1680 | { |
| 1681 | contents[2] = DW_EH_PE_udata4; /* FDE count encoding. */ |
| 1682 | contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; /* Search table enc. */ |
| 1683 | } |
| 1684 | else |
| 1685 | { |
| 1686 | contents[2] = DW_EH_PE_omit; |
| 1687 | contents[3] = DW_EH_PE_omit; |
| 1688 | } |
| 1689 | bfd_put_32 (abfd, encoded_eh_frame, contents + 4); |
| 1690 | |
| 1691 | if (contents[2] != DW_EH_PE_omit) |
| 1692 | { |
| 1693 | unsigned int i; |
| 1694 | |
| 1695 | bfd_put_32 (abfd, hdr_info->fde_count, contents + EH_FRAME_HDR_SIZE); |
| 1696 | qsort (hdr_info->array, hdr_info->fde_count, sizeof (*hdr_info->array), |
| 1697 | vma_compare); |
| 1698 | for (i = 0; i < hdr_info->fde_count; i++) |
| 1699 | { |
| 1700 | bfd_put_32 (abfd, |
| 1701 | hdr_info->array[i].initial_loc |
| 1702 | - sec->output_section->vma, |
| 1703 | contents + EH_FRAME_HDR_SIZE + i * 8 + 4); |
| 1704 | bfd_put_32 (abfd, |
| 1705 | hdr_info->array[i].fde - sec->output_section->vma, |
| 1706 | contents + EH_FRAME_HDR_SIZE + i * 8 + 8); |
| 1707 | } |
| 1708 | } |
| 1709 | |
| 1710 | retval = bfd_set_section_contents (abfd, sec->output_section, |
| 1711 | contents, (file_ptr) sec->output_offset, |
| 1712 | sec->size); |
| 1713 | free (contents); |
| 1714 | return retval; |
| 1715 | } |
| 1716 | |
| 1717 | /* Return the width of FDE addresses. This is the default implementation. */ |
| 1718 | |
| 1719 | unsigned int |
| 1720 | _bfd_elf_eh_frame_address_size (bfd *abfd, asection *sec ATTRIBUTE_UNUSED) |
| 1721 | { |
| 1722 | return elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64 ? 8 : 4; |
| 1723 | } |
| 1724 | |
| 1725 | /* Decide whether we can use a PC-relative encoding within the given |
| 1726 | EH frame section. This is the default implementation. */ |
| 1727 | |
| 1728 | bfd_boolean |
| 1729 | _bfd_elf_can_make_relative (bfd *input_bfd ATTRIBUTE_UNUSED, |
| 1730 | struct bfd_link_info *info ATTRIBUTE_UNUSED, |
| 1731 | asection *eh_frame_section ATTRIBUTE_UNUSED) |
| 1732 | { |
| 1733 | return TRUE; |
| 1734 | } |
| 1735 | |
| 1736 | /* Select an encoding for the given address. Preference is given to |
| 1737 | PC-relative addressing modes. */ |
| 1738 | |
| 1739 | bfd_byte |
| 1740 | _bfd_elf_encode_eh_address (bfd *abfd ATTRIBUTE_UNUSED, |
| 1741 | struct bfd_link_info *info ATTRIBUTE_UNUSED, |
| 1742 | asection *osec, bfd_vma offset, |
| 1743 | asection *loc_sec, bfd_vma loc_offset, |
| 1744 | bfd_vma *encoded) |
| 1745 | { |
| 1746 | *encoded = osec->vma + offset - |
| 1747 | (loc_sec->output_section->vma + loc_sec->output_offset + loc_offset); |
| 1748 | return DW_EH_PE_pcrel | DW_EH_PE_sdata4; |
| 1749 | } |