| 1 | /* .eh_frame section optimization. |
| 2 | Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
| 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 "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 = (const struct cie *) e1; |
| 219 | const struct cie *c2 = (const struct cie *) 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 = (const struct cie *) 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 | /* Convert absolute encoding ENCODING into PC-relative form. |
| 427 | SIZE is the size of a pointer. */ |
| 428 | |
| 429 | static unsigned char |
| 430 | make_pc_relative (unsigned char encoding, unsigned int ptr_size) |
| 431 | { |
| 432 | if ((encoding & 0x7f) == DW_EH_PE_absptr) |
| 433 | switch (ptr_size) |
| 434 | { |
| 435 | case 2: |
| 436 | encoding |= DW_EH_PE_sdata2; |
| 437 | break; |
| 438 | case 4: |
| 439 | encoding |= DW_EH_PE_sdata4; |
| 440 | break; |
| 441 | case 8: |
| 442 | encoding |= DW_EH_PE_sdata8; |
| 443 | break; |
| 444 | } |
| 445 | return encoding | DW_EH_PE_pcrel; |
| 446 | } |
| 447 | |
| 448 | /* Called before calling _bfd_elf_parse_eh_frame on every input bfd's |
| 449 | .eh_frame section. */ |
| 450 | |
| 451 | void |
| 452 | _bfd_elf_begin_eh_frame_parsing (struct bfd_link_info *info) |
| 453 | { |
| 454 | struct eh_frame_hdr_info *hdr_info; |
| 455 | |
| 456 | hdr_info = &elf_hash_table (info)->eh_info; |
| 457 | hdr_info->merge_cies = !info->relocatable; |
| 458 | } |
| 459 | |
| 460 | /* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the |
| 461 | information in the section's sec_info field on success. COOKIE |
| 462 | describes the relocations in SEC. */ |
| 463 | |
| 464 | void |
| 465 | _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info, |
| 466 | asection *sec, struct elf_reloc_cookie *cookie) |
| 467 | { |
| 468 | #define REQUIRE(COND) \ |
| 469 | do \ |
| 470 | if (!(COND)) \ |
| 471 | goto free_no_table; \ |
| 472 | while (0) |
| 473 | |
| 474 | bfd_byte *ehbuf = NULL, *buf, *end; |
| 475 | bfd_byte *last_fde; |
| 476 | struct eh_cie_fde *this_inf; |
| 477 | unsigned int hdr_length, hdr_id; |
| 478 | unsigned int cie_count; |
| 479 | struct cie *cie, *local_cies = NULL; |
| 480 | struct elf_link_hash_table *htab; |
| 481 | struct eh_frame_hdr_info *hdr_info; |
| 482 | struct eh_frame_sec_info *sec_info = NULL; |
| 483 | unsigned int ptr_size; |
| 484 | unsigned int num_cies; |
| 485 | unsigned int num_entries; |
| 486 | elf_gc_mark_hook_fn gc_mark_hook; |
| 487 | |
| 488 | htab = elf_hash_table (info); |
| 489 | hdr_info = &htab->eh_info; |
| 490 | if (hdr_info->parsed_eh_frames) |
| 491 | return; |
| 492 | |
| 493 | if (sec->size == 0) |
| 494 | { |
| 495 | /* This file does not contain .eh_frame information. */ |
| 496 | return; |
| 497 | } |
| 498 | |
| 499 | if (bfd_is_abs_section (sec->output_section)) |
| 500 | { |
| 501 | /* At least one of the sections is being discarded from the |
| 502 | link, so we should just ignore them. */ |
| 503 | return; |
| 504 | } |
| 505 | |
| 506 | /* Read the frame unwind information from abfd. */ |
| 507 | |
| 508 | REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf)); |
| 509 | |
| 510 | if (sec->size >= 4 |
| 511 | && bfd_get_32 (abfd, ehbuf) == 0 |
| 512 | && cookie->rel == cookie->relend) |
| 513 | { |
| 514 | /* Empty .eh_frame section. */ |
| 515 | free (ehbuf); |
| 516 | return; |
| 517 | } |
| 518 | |
| 519 | /* If .eh_frame section size doesn't fit into int, we cannot handle |
| 520 | it (it would need to use 64-bit .eh_frame format anyway). */ |
| 521 | REQUIRE (sec->size == (unsigned int) sec->size); |
| 522 | |
| 523 | ptr_size = (get_elf_backend_data (abfd) |
| 524 | ->elf_backend_eh_frame_address_size (abfd, sec)); |
| 525 | REQUIRE (ptr_size != 0); |
| 526 | |
| 527 | /* Go through the section contents and work out how many FDEs and |
| 528 | CIEs there are. */ |
| 529 | buf = ehbuf; |
| 530 | end = ehbuf + sec->size; |
| 531 | num_cies = 0; |
| 532 | num_entries = 0; |
| 533 | while (buf != end) |
| 534 | { |
| 535 | num_entries++; |
| 536 | |
| 537 | /* Read the length of the entry. */ |
| 538 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 539 | hdr_length = bfd_get_32 (abfd, buf - 4); |
| 540 | |
| 541 | /* 64-bit .eh_frame is not supported. */ |
| 542 | REQUIRE (hdr_length != 0xffffffff); |
| 543 | if (hdr_length == 0) |
| 544 | break; |
| 545 | |
| 546 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 547 | hdr_id = bfd_get_32 (abfd, buf - 4); |
| 548 | if (hdr_id == 0) |
| 549 | num_cies++; |
| 550 | |
| 551 | REQUIRE (skip_bytes (&buf, end, hdr_length - 4)); |
| 552 | } |
| 553 | |
| 554 | sec_info = (struct eh_frame_sec_info *) |
| 555 | bfd_zmalloc (sizeof (struct eh_frame_sec_info) |
| 556 | + (num_entries - 1) * sizeof (struct eh_cie_fde)); |
| 557 | REQUIRE (sec_info); |
| 558 | |
| 559 | /* We need to have a "struct cie" for each CIE in this section. */ |
| 560 | local_cies = (struct cie *) bfd_zmalloc (num_cies * sizeof (*local_cies)); |
| 561 | REQUIRE (local_cies); |
| 562 | |
| 563 | /* FIXME: octets_per_byte. */ |
| 564 | #define ENSURE_NO_RELOCS(buf) \ |
| 565 | REQUIRE (!(cookie->rel < cookie->relend \ |
| 566 | && (cookie->rel->r_offset \ |
| 567 | < (bfd_size_type) ((buf) - ehbuf)) \ |
| 568 | && cookie->rel->r_info != 0)) |
| 569 | |
| 570 | /* FIXME: octets_per_byte. */ |
| 571 | #define SKIP_RELOCS(buf) \ |
| 572 | while (cookie->rel < cookie->relend \ |
| 573 | && (cookie->rel->r_offset \ |
| 574 | < (bfd_size_type) ((buf) - ehbuf))) \ |
| 575 | cookie->rel++ |
| 576 | |
| 577 | /* FIXME: octets_per_byte. */ |
| 578 | #define GET_RELOC(buf) \ |
| 579 | ((cookie->rel < cookie->relend \ |
| 580 | && (cookie->rel->r_offset \ |
| 581 | == (bfd_size_type) ((buf) - ehbuf))) \ |
| 582 | ? cookie->rel : NULL) |
| 583 | |
| 584 | buf = ehbuf; |
| 585 | cie_count = 0; |
| 586 | gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook; |
| 587 | while ((bfd_size_type) (buf - ehbuf) != sec->size) |
| 588 | { |
| 589 | char *aug; |
| 590 | bfd_byte *start, *insns, *insns_end; |
| 591 | bfd_size_type length; |
| 592 | unsigned int set_loc_count; |
| 593 | |
| 594 | this_inf = sec_info->entry + sec_info->count; |
| 595 | last_fde = buf; |
| 596 | |
| 597 | /* Read the length of the entry. */ |
| 598 | REQUIRE (skip_bytes (&buf, ehbuf + sec->size, 4)); |
| 599 | hdr_length = bfd_get_32 (abfd, buf - 4); |
| 600 | |
| 601 | /* The CIE/FDE must be fully contained in this input section. */ |
| 602 | REQUIRE ((bfd_size_type) (buf - ehbuf) + hdr_length <= sec->size); |
| 603 | end = buf + hdr_length; |
| 604 | |
| 605 | this_inf->offset = last_fde - ehbuf; |
| 606 | this_inf->size = 4 + hdr_length; |
| 607 | this_inf->reloc_index = cookie->rel - cookie->rels; |
| 608 | |
| 609 | if (hdr_length == 0) |
| 610 | { |
| 611 | /* A zero-length CIE should only be found at the end of |
| 612 | the section. */ |
| 613 | REQUIRE ((bfd_size_type) (buf - ehbuf) == sec->size); |
| 614 | ENSURE_NO_RELOCS (buf); |
| 615 | sec_info->count++; |
| 616 | break; |
| 617 | } |
| 618 | |
| 619 | REQUIRE (skip_bytes (&buf, end, 4)); |
| 620 | hdr_id = bfd_get_32 (abfd, buf - 4); |
| 621 | |
| 622 | if (hdr_id == 0) |
| 623 | { |
| 624 | unsigned int initial_insn_length; |
| 625 | |
| 626 | /* CIE */ |
| 627 | this_inf->cie = 1; |
| 628 | |
| 629 | /* Point CIE to one of the section-local cie structures. */ |
| 630 | cie = local_cies + cie_count++; |
| 631 | |
| 632 | cie->cie_inf = this_inf; |
| 633 | cie->length = hdr_length; |
| 634 | cie->output_sec = sec->output_section; |
| 635 | start = buf; |
| 636 | REQUIRE (read_byte (&buf, end, &cie->version)); |
| 637 | |
| 638 | /* Cannot handle unknown versions. */ |
| 639 | REQUIRE (cie->version == 1 || cie->version == 3); |
| 640 | REQUIRE (strlen ((char *) buf) < sizeof (cie->augmentation)); |
| 641 | |
| 642 | strcpy (cie->augmentation, (char *) buf); |
| 643 | buf = (bfd_byte *) strchr ((char *) buf, '\0') + 1; |
| 644 | ENSURE_NO_RELOCS (buf); |
| 645 | if (buf[0] == 'e' && buf[1] == 'h') |
| 646 | { |
| 647 | /* GCC < 3.0 .eh_frame CIE */ |
| 648 | /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__ |
| 649 | is private to each CIE, so we don't need it for anything. |
| 650 | Just skip it. */ |
| 651 | REQUIRE (skip_bytes (&buf, end, ptr_size)); |
| 652 | SKIP_RELOCS (buf); |
| 653 | } |
| 654 | REQUIRE (read_uleb128 (&buf, end, &cie->code_align)); |
| 655 | REQUIRE (read_sleb128 (&buf, end, &cie->data_align)); |
| 656 | if (cie->version == 1) |
| 657 | { |
| 658 | REQUIRE (buf < end); |
| 659 | cie->ra_column = *buf++; |
| 660 | } |
| 661 | else |
| 662 | REQUIRE (read_uleb128 (&buf, end, &cie->ra_column)); |
| 663 | ENSURE_NO_RELOCS (buf); |
| 664 | cie->lsda_encoding = DW_EH_PE_omit; |
| 665 | cie->fde_encoding = DW_EH_PE_omit; |
| 666 | cie->per_encoding = DW_EH_PE_omit; |
| 667 | aug = cie->augmentation; |
| 668 | if (aug[0] != 'e' || aug[1] != 'h') |
| 669 | { |
| 670 | if (*aug == 'z') |
| 671 | { |
| 672 | aug++; |
| 673 | REQUIRE (read_uleb128 (&buf, end, &cie->augmentation_size)); |
| 674 | ENSURE_NO_RELOCS (buf); |
| 675 | } |
| 676 | |
| 677 | while (*aug != '\0') |
| 678 | switch (*aug++) |
| 679 | { |
| 680 | case 'L': |
| 681 | REQUIRE (read_byte (&buf, end, &cie->lsda_encoding)); |
| 682 | ENSURE_NO_RELOCS (buf); |
| 683 | REQUIRE (get_DW_EH_PE_width (cie->lsda_encoding, ptr_size)); |
| 684 | break; |
| 685 | case 'R': |
| 686 | REQUIRE (read_byte (&buf, end, &cie->fde_encoding)); |
| 687 | ENSURE_NO_RELOCS (buf); |
| 688 | REQUIRE (get_DW_EH_PE_width (cie->fde_encoding, ptr_size)); |
| 689 | break; |
| 690 | case 'S': |
| 691 | break; |
| 692 | case 'P': |
| 693 | { |
| 694 | int per_width; |
| 695 | |
| 696 | REQUIRE (read_byte (&buf, end, &cie->per_encoding)); |
| 697 | per_width = get_DW_EH_PE_width (cie->per_encoding, |
| 698 | ptr_size); |
| 699 | REQUIRE (per_width); |
| 700 | if ((cie->per_encoding & 0x70) == DW_EH_PE_aligned) |
| 701 | { |
| 702 | length = -(buf - ehbuf) & (per_width - 1); |
| 703 | REQUIRE (skip_bytes (&buf, end, length)); |
| 704 | } |
| 705 | this_inf->u.cie.personality_offset = buf - start; |
| 706 | ENSURE_NO_RELOCS (buf); |
| 707 | /* Ensure we have a reloc here. */ |
| 708 | REQUIRE (GET_RELOC (buf)); |
| 709 | cie->personality.reloc_index |
| 710 | = cookie->rel - cookie->rels; |
| 711 | /* Cope with MIPS-style composite relocations. */ |
| 712 | do |
| 713 | cookie->rel++; |
| 714 | while (GET_RELOC (buf) != NULL); |
| 715 | REQUIRE (skip_bytes (&buf, end, per_width)); |
| 716 | } |
| 717 | break; |
| 718 | default: |
| 719 | /* Unrecognized augmentation. Better bail out. */ |
| 720 | goto free_no_table; |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | /* For shared libraries, try to get rid of as many RELATIVE relocs |
| 725 | as possible. */ |
| 726 | if (info->shared |
| 727 | && (get_elf_backend_data (abfd) |
| 728 | ->elf_backend_can_make_relative_eh_frame |
| 729 | (abfd, info, sec))) |
| 730 | { |
| 731 | if ((cie->fde_encoding & 0x70) == DW_EH_PE_absptr) |
| 732 | this_inf->make_relative = 1; |
| 733 | /* If the CIE doesn't already have an 'R' entry, it's fairly |
| 734 | easy to add one, provided that there's no aligned data |
| 735 | after the augmentation string. */ |
| 736 | else if (cie->fde_encoding == DW_EH_PE_omit |
| 737 | && (cie->per_encoding & 0x70) != DW_EH_PE_aligned) |
| 738 | { |
| 739 | if (*cie->augmentation == 0) |
| 740 | this_inf->add_augmentation_size = 1; |
| 741 | this_inf->u.cie.add_fde_encoding = 1; |
| 742 | this_inf->make_relative = 1; |
| 743 | } |
| 744 | |
| 745 | if ((cie->lsda_encoding & 0x70) == DW_EH_PE_absptr) |
| 746 | cie->can_make_lsda_relative = 1; |
| 747 | } |
| 748 | |
| 749 | /* If FDE encoding was not specified, it defaults to |
| 750 | DW_EH_absptr. */ |
| 751 | if (cie->fde_encoding == DW_EH_PE_omit) |
| 752 | cie->fde_encoding = DW_EH_PE_absptr; |
| 753 | |
| 754 | initial_insn_length = end - buf; |
| 755 | if (initial_insn_length <= sizeof (cie->initial_instructions)) |
| 756 | { |
| 757 | cie->initial_insn_length = initial_insn_length; |
| 758 | memcpy (cie->initial_instructions, buf, initial_insn_length); |
| 759 | } |
| 760 | insns = buf; |
| 761 | buf += initial_insn_length; |
| 762 | ENSURE_NO_RELOCS (buf); |
| 763 | |
| 764 | if (hdr_info->merge_cies) |
| 765 | this_inf->u.cie.u.full_cie = cie; |
| 766 | this_inf->u.cie.per_encoding_relative |
| 767 | = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel; |
| 768 | } |
| 769 | else |
| 770 | { |
| 771 | asection *rsec; |
| 772 | |
| 773 | /* Find the corresponding CIE. */ |
| 774 | unsigned int cie_offset = this_inf->offset + 4 - hdr_id; |
| 775 | for (cie = local_cies; cie < local_cies + cie_count; cie++) |
| 776 | if (cie_offset == cie->cie_inf->offset) |
| 777 | break; |
| 778 | |
| 779 | /* Ensure this FDE references one of the CIEs in this input |
| 780 | section. */ |
| 781 | REQUIRE (cie != local_cies + cie_count); |
| 782 | this_inf->u.fde.cie_inf = cie->cie_inf; |
| 783 | this_inf->make_relative = cie->cie_inf->make_relative; |
| 784 | this_inf->add_augmentation_size |
| 785 | = cie->cie_inf->add_augmentation_size; |
| 786 | |
| 787 | ENSURE_NO_RELOCS (buf); |
| 788 | REQUIRE (GET_RELOC (buf)); |
| 789 | |
| 790 | /* Chain together the FDEs for each section. */ |
| 791 | rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie); |
| 792 | /* RSEC will be NULL if FDE was cleared out as it was belonging to |
| 793 | a discarded SHT_GROUP. */ |
| 794 | if (rsec) |
| 795 | { |
| 796 | REQUIRE (rsec->owner == abfd); |
| 797 | this_inf->u.fde.next_for_section = elf_fde_list (rsec); |
| 798 | elf_fde_list (rsec) = this_inf; |
| 799 | } |
| 800 | |
| 801 | /* Skip the initial location and address range. */ |
| 802 | start = buf; |
| 803 | length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); |
| 804 | REQUIRE (skip_bytes (&buf, end, 2 * length)); |
| 805 | |
| 806 | /* Skip the augmentation size, if present. */ |
| 807 | if (cie->augmentation[0] == 'z') |
| 808 | REQUIRE (read_uleb128 (&buf, end, &length)); |
| 809 | else |
| 810 | length = 0; |
| 811 | |
| 812 | /* Of the supported augmentation characters above, only 'L' |
| 813 | adds augmentation data to the FDE. This code would need to |
| 814 | be adjusted if any future augmentations do the same thing. */ |
| 815 | if (cie->lsda_encoding != DW_EH_PE_omit) |
| 816 | { |
| 817 | SKIP_RELOCS (buf); |
| 818 | if (cie->can_make_lsda_relative && GET_RELOC (buf)) |
| 819 | cie->cie_inf->u.cie.make_lsda_relative = 1; |
| 820 | this_inf->lsda_offset = buf - start; |
| 821 | /* If there's no 'z' augmentation, we don't know where the |
| 822 | CFA insns begin. Assume no padding. */ |
| 823 | if (cie->augmentation[0] != 'z') |
| 824 | length = end - buf; |
| 825 | } |
| 826 | |
| 827 | /* Skip over the augmentation data. */ |
| 828 | REQUIRE (skip_bytes (&buf, end, length)); |
| 829 | insns = buf; |
| 830 | |
| 831 | buf = last_fde + 4 + hdr_length; |
| 832 | |
| 833 | /* For NULL RSEC (cleared FDE belonging to a discarded section) |
| 834 | the relocations are commonly cleared. We do not sanity check if |
| 835 | all these relocations are cleared as (1) relocations to |
| 836 | .gcc_except_table will remain uncleared (they will get dropped |
| 837 | with the drop of this unused FDE) and (2) BFD already safely drops |
| 838 | relocations of any type to .eh_frame by |
| 839 | elf_section_ignore_discarded_relocs. |
| 840 | TODO: The .gcc_except_table entries should be also filtered as |
| 841 | .eh_frame entries; or GCC could rather use COMDAT for them. */ |
| 842 | SKIP_RELOCS (buf); |
| 843 | } |
| 844 | |
| 845 | /* Try to interpret the CFA instructions and find the first |
| 846 | padding nop. Shrink this_inf's size so that it doesn't |
| 847 | include the padding. */ |
| 848 | length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); |
| 849 | set_loc_count = 0; |
| 850 | insns_end = skip_non_nops (insns, end, length, &set_loc_count); |
| 851 | /* If we don't understand the CFA instructions, we can't know |
| 852 | what needs to be adjusted there. */ |
| 853 | if (insns_end == NULL |
| 854 | /* For the time being we don't support DW_CFA_set_loc in |
| 855 | CIE instructions. */ |
| 856 | || (set_loc_count && this_inf->cie)) |
| 857 | goto free_no_table; |
| 858 | this_inf->size -= end - insns_end; |
| 859 | if (insns_end != end && this_inf->cie) |
| 860 | { |
| 861 | cie->initial_insn_length -= end - insns_end; |
| 862 | cie->length -= end - insns_end; |
| 863 | } |
| 864 | if (set_loc_count |
| 865 | && ((cie->fde_encoding & 0x70) == DW_EH_PE_pcrel |
| 866 | || this_inf->make_relative)) |
| 867 | { |
| 868 | unsigned int cnt; |
| 869 | bfd_byte *p; |
| 870 | |
| 871 | this_inf->set_loc = (unsigned int *) |
| 872 | bfd_malloc ((set_loc_count + 1) * sizeof (unsigned int)); |
| 873 | REQUIRE (this_inf->set_loc); |
| 874 | this_inf->set_loc[0] = set_loc_count; |
| 875 | p = insns; |
| 876 | cnt = 0; |
| 877 | while (p < end) |
| 878 | { |
| 879 | if (*p == DW_CFA_set_loc) |
| 880 | this_inf->set_loc[++cnt] = p + 1 - start; |
| 881 | REQUIRE (skip_cfa_op (&p, end, length)); |
| 882 | } |
| 883 | } |
| 884 | |
| 885 | this_inf->removed = 1; |
| 886 | this_inf->fde_encoding = cie->fde_encoding; |
| 887 | this_inf->lsda_encoding = cie->lsda_encoding; |
| 888 | sec_info->count++; |
| 889 | } |
| 890 | BFD_ASSERT (sec_info->count == num_entries); |
| 891 | BFD_ASSERT (cie_count == num_cies); |
| 892 | |
| 893 | elf_section_data (sec)->sec_info = sec_info; |
| 894 | sec->sec_info_type = ELF_INFO_TYPE_EH_FRAME; |
| 895 | if (hdr_info->merge_cies) |
| 896 | { |
| 897 | sec_info->cies = local_cies; |
| 898 | local_cies = NULL; |
| 899 | } |
| 900 | goto success; |
| 901 | |
| 902 | free_no_table: |
| 903 | (*info->callbacks->einfo) |
| 904 | (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"), |
| 905 | abfd, sec); |
| 906 | hdr_info->table = FALSE; |
| 907 | if (sec_info) |
| 908 | free (sec_info); |
| 909 | success: |
| 910 | if (ehbuf) |
| 911 | free (ehbuf); |
| 912 | if (local_cies) |
| 913 | free (local_cies); |
| 914 | #undef REQUIRE |
| 915 | } |
| 916 | |
| 917 | /* Finish a pass over all .eh_frame sections. */ |
| 918 | |
| 919 | void |
| 920 | _bfd_elf_end_eh_frame_parsing (struct bfd_link_info *info) |
| 921 | { |
| 922 | struct eh_frame_hdr_info *hdr_info; |
| 923 | |
| 924 | hdr_info = &elf_hash_table (info)->eh_info; |
| 925 | hdr_info->parsed_eh_frames = TRUE; |
| 926 | } |
| 927 | |
| 928 | /* Mark all relocations against CIE or FDE ENT, which occurs in |
| 929 | .eh_frame section SEC. COOKIE describes the relocations in SEC; |
| 930 | its "rel" field can be changed freely. */ |
| 931 | |
| 932 | static bfd_boolean |
| 933 | mark_entry (struct bfd_link_info *info, asection *sec, |
| 934 | struct eh_cie_fde *ent, elf_gc_mark_hook_fn gc_mark_hook, |
| 935 | struct elf_reloc_cookie *cookie) |
| 936 | { |
| 937 | /* FIXME: octets_per_byte. */ |
| 938 | for (cookie->rel = cookie->rels + ent->reloc_index; |
| 939 | cookie->rel < cookie->relend |
| 940 | && cookie->rel->r_offset < ent->offset + ent->size; |
| 941 | cookie->rel++) |
| 942 | if (!_bfd_elf_gc_mark_reloc (info, sec, gc_mark_hook, cookie)) |
| 943 | return FALSE; |
| 944 | |
| 945 | return TRUE; |
| 946 | } |
| 947 | |
| 948 | /* Mark all the relocations against FDEs that relate to code in input |
| 949 | section SEC. The FDEs belong to .eh_frame section EH_FRAME, whose |
| 950 | relocations are described by COOKIE. */ |
| 951 | |
| 952 | bfd_boolean |
| 953 | _bfd_elf_gc_mark_fdes (struct bfd_link_info *info, asection *sec, |
| 954 | asection *eh_frame, elf_gc_mark_hook_fn gc_mark_hook, |
| 955 | struct elf_reloc_cookie *cookie) |
| 956 | { |
| 957 | struct eh_cie_fde *fde, *cie; |
| 958 | |
| 959 | for (fde = elf_fde_list (sec); fde; fde = fde->u.fde.next_for_section) |
| 960 | { |
| 961 | if (!mark_entry (info, eh_frame, fde, gc_mark_hook, cookie)) |
| 962 | return FALSE; |
| 963 | |
| 964 | /* At this stage, all cie_inf fields point to local CIEs, so we |
| 965 | can use the same cookie to refer to them. */ |
| 966 | cie = fde->u.fde.cie_inf; |
| 967 | if (!cie->u.cie.gc_mark) |
| 968 | { |
| 969 | cie->u.cie.gc_mark = 1; |
| 970 | if (!mark_entry (info, eh_frame, cie, gc_mark_hook, cookie)) |
| 971 | return FALSE; |
| 972 | } |
| 973 | } |
| 974 | return TRUE; |
| 975 | } |
| 976 | |
| 977 | /* Input section SEC of ABFD is an .eh_frame section that contains the |
| 978 | CIE described by CIE_INF. Return a version of CIE_INF that is going |
| 979 | to be kept in the output, adding CIE_INF to the output if necessary. |
| 980 | |
| 981 | HDR_INFO is the .eh_frame_hdr information and COOKIE describes the |
| 982 | relocations in REL. */ |
| 983 | |
| 984 | static struct eh_cie_fde * |
| 985 | find_merged_cie (bfd *abfd, struct bfd_link_info *info, asection *sec, |
| 986 | struct eh_frame_hdr_info *hdr_info, |
| 987 | struct elf_reloc_cookie *cookie, |
| 988 | struct eh_cie_fde *cie_inf) |
| 989 | { |
| 990 | unsigned long r_symndx; |
| 991 | struct cie *cie, *new_cie; |
| 992 | Elf_Internal_Rela *rel; |
| 993 | void **loc; |
| 994 | |
| 995 | /* Use CIE_INF if we have already decided to keep it. */ |
| 996 | if (!cie_inf->removed) |
| 997 | return cie_inf; |
| 998 | |
| 999 | /* If we have merged CIE_INF with another CIE, use that CIE instead. */ |
| 1000 | if (cie_inf->u.cie.merged) |
| 1001 | return cie_inf->u.cie.u.merged_with; |
| 1002 | |
| 1003 | cie = cie_inf->u.cie.u.full_cie; |
| 1004 | |
| 1005 | /* Assume we will need to keep CIE_INF. */ |
| 1006 | cie_inf->removed = 0; |
| 1007 | cie_inf->u.cie.u.sec = sec; |
| 1008 | |
| 1009 | /* If we are not merging CIEs, use CIE_INF. */ |
| 1010 | if (cie == NULL) |
| 1011 | return cie_inf; |
| 1012 | |
| 1013 | if (cie->per_encoding != DW_EH_PE_omit) |
| 1014 | { |
| 1015 | bfd_boolean per_binds_local; |
| 1016 | |
| 1017 | /* Work out the address of personality routine, either as an absolute |
| 1018 | value or as a symbol. */ |
| 1019 | rel = cookie->rels + cie->personality.reloc_index; |
| 1020 | memset (&cie->personality, 0, sizeof (cie->personality)); |
| 1021 | #ifdef BFD64 |
| 1022 | if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64) |
| 1023 | r_symndx = ELF64_R_SYM (rel->r_info); |
| 1024 | else |
| 1025 | #endif |
| 1026 | r_symndx = ELF32_R_SYM (rel->r_info); |
| 1027 | if (r_symndx >= cookie->locsymcount |
| 1028 | || ELF_ST_BIND (cookie->locsyms[r_symndx].st_info) != STB_LOCAL) |
| 1029 | { |
| 1030 | struct elf_link_hash_entry *h; |
| 1031 | |
| 1032 | r_symndx -= cookie->extsymoff; |
| 1033 | h = cookie->sym_hashes[r_symndx]; |
| 1034 | |
| 1035 | while (h->root.type == bfd_link_hash_indirect |
| 1036 | || h->root.type == bfd_link_hash_warning) |
| 1037 | h = (struct elf_link_hash_entry *) h->root.u.i.link; |
| 1038 | |
| 1039 | cie->personality.h = h; |
| 1040 | per_binds_local = SYMBOL_REFERENCES_LOCAL (info, h); |
| 1041 | } |
| 1042 | else |
| 1043 | { |
| 1044 | Elf_Internal_Sym *sym; |
| 1045 | asection *sym_sec; |
| 1046 | |
| 1047 | sym = &cookie->locsyms[r_symndx]; |
| 1048 | sym_sec = bfd_section_from_elf_index (abfd, sym->st_shndx); |
| 1049 | if (sym_sec == NULL) |
| 1050 | return cie_inf; |
| 1051 | |
| 1052 | if (sym_sec->kept_section != NULL) |
| 1053 | sym_sec = sym_sec->kept_section; |
| 1054 | if (sym_sec->output_section == NULL) |
| 1055 | return cie_inf; |
| 1056 | |
| 1057 | cie->local_personality = 1; |
| 1058 | cie->personality.val = (sym->st_value |
| 1059 | + sym_sec->output_offset |
| 1060 | + sym_sec->output_section->vma); |
| 1061 | per_binds_local = TRUE; |
| 1062 | } |
| 1063 | |
| 1064 | if (per_binds_local |
| 1065 | && info->shared |
| 1066 | && (cie->per_encoding & 0x70) == DW_EH_PE_absptr |
| 1067 | && (get_elf_backend_data (abfd) |
| 1068 | ->elf_backend_can_make_relative_eh_frame (abfd, info, sec))) |
| 1069 | { |
| 1070 | cie_inf->u.cie.make_per_encoding_relative = 1; |
| 1071 | cie_inf->u.cie.per_encoding_relative = 1; |
| 1072 | } |
| 1073 | } |
| 1074 | |
| 1075 | /* See if we can merge this CIE with an earlier one. */ |
| 1076 | cie->output_sec = sec->output_section; |
| 1077 | cie_compute_hash (cie); |
| 1078 | if (hdr_info->cies == NULL) |
| 1079 | { |
| 1080 | hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free); |
| 1081 | if (hdr_info->cies == NULL) |
| 1082 | return cie_inf; |
| 1083 | } |
| 1084 | loc = htab_find_slot_with_hash (hdr_info->cies, cie, cie->hash, INSERT); |
| 1085 | if (loc == NULL) |
| 1086 | return cie_inf; |
| 1087 | |
| 1088 | new_cie = (struct cie *) *loc; |
| 1089 | if (new_cie == NULL) |
| 1090 | { |
| 1091 | /* Keep CIE_INF and record it in the hash table. */ |
| 1092 | new_cie = (struct cie *) malloc (sizeof (struct cie)); |
| 1093 | if (new_cie == NULL) |
| 1094 | return cie_inf; |
| 1095 | |
| 1096 | memcpy (new_cie, cie, sizeof (struct cie)); |
| 1097 | *loc = new_cie; |
| 1098 | } |
| 1099 | else |
| 1100 | { |
| 1101 | /* Merge CIE_INF with NEW_CIE->CIE_INF. */ |
| 1102 | cie_inf->removed = 1; |
| 1103 | cie_inf->u.cie.merged = 1; |
| 1104 | cie_inf->u.cie.u.merged_with = new_cie->cie_inf; |
| 1105 | if (cie_inf->u.cie.make_lsda_relative) |
| 1106 | new_cie->cie_inf->u.cie.make_lsda_relative = 1; |
| 1107 | } |
| 1108 | return new_cie->cie_inf; |
| 1109 | } |
| 1110 | |
| 1111 | /* This function is called for each input file before the .eh_frame |
| 1112 | section is relocated. It discards duplicate CIEs and FDEs for discarded |
| 1113 | functions. The function returns TRUE iff any entries have been |
| 1114 | deleted. */ |
| 1115 | |
| 1116 | bfd_boolean |
| 1117 | _bfd_elf_discard_section_eh_frame |
| 1118 | (bfd *abfd, struct bfd_link_info *info, asection *sec, |
| 1119 | bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *), |
| 1120 | struct elf_reloc_cookie *cookie) |
| 1121 | { |
| 1122 | struct eh_cie_fde *ent; |
| 1123 | struct eh_frame_sec_info *sec_info; |
| 1124 | struct eh_frame_hdr_info *hdr_info; |
| 1125 | unsigned int ptr_size, offset; |
| 1126 | |
| 1127 | sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; |
| 1128 | if (sec_info == NULL) |
| 1129 | return FALSE; |
| 1130 | |
| 1131 | hdr_info = &elf_hash_table (info)->eh_info; |
| 1132 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1133 | if (ent->size == 4) |
| 1134 | /* There should only be one zero terminator, on the last input |
| 1135 | file supplying .eh_frame (crtend.o). Remove any others. */ |
| 1136 | ent->removed = sec->map_head.s != NULL; |
| 1137 | else if (!ent->cie) |
| 1138 | { |
| 1139 | cookie->rel = cookie->rels + ent->reloc_index; |
| 1140 | /* FIXME: octets_per_byte. */ |
| 1141 | BFD_ASSERT (cookie->rel < cookie->relend |
| 1142 | && cookie->rel->r_offset == ent->offset + 8); |
| 1143 | if (!(*reloc_symbol_deleted_p) (ent->offset + 8, cookie)) |
| 1144 | { |
| 1145 | if (info->shared |
| 1146 | && (((ent->fde_encoding & 0x70) == DW_EH_PE_absptr |
| 1147 | && ent->make_relative == 0) |
| 1148 | || (ent->fde_encoding & 0x70) == DW_EH_PE_aligned)) |
| 1149 | { |
| 1150 | /* If a shared library uses absolute pointers |
| 1151 | which we cannot turn into PC relative, |
| 1152 | don't create the binary search table, |
| 1153 | since it is affected by runtime relocations. */ |
| 1154 | hdr_info->table = FALSE; |
| 1155 | (*info->callbacks->einfo) |
| 1156 | (_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr" |
| 1157 | " table being created.\n"), abfd, sec); |
| 1158 | } |
| 1159 | ent->removed = 0; |
| 1160 | hdr_info->fde_count++; |
| 1161 | ent->u.fde.cie_inf = find_merged_cie (abfd, info, sec, hdr_info, |
| 1162 | cookie, ent->u.fde.cie_inf); |
| 1163 | } |
| 1164 | } |
| 1165 | |
| 1166 | if (sec_info->cies) |
| 1167 | { |
| 1168 | free (sec_info->cies); |
| 1169 | sec_info->cies = NULL; |
| 1170 | } |
| 1171 | |
| 1172 | ptr_size = (get_elf_backend_data (sec->owner) |
| 1173 | ->elf_backend_eh_frame_address_size (sec->owner, sec)); |
| 1174 | offset = 0; |
| 1175 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1176 | if (!ent->removed) |
| 1177 | { |
| 1178 | ent->new_offset = offset; |
| 1179 | offset += size_of_output_cie_fde (ent, ptr_size); |
| 1180 | } |
| 1181 | |
| 1182 | sec->rawsize = sec->size; |
| 1183 | sec->size = offset; |
| 1184 | return offset != sec->rawsize; |
| 1185 | } |
| 1186 | |
| 1187 | /* This function is called for .eh_frame_hdr section after |
| 1188 | _bfd_elf_discard_section_eh_frame has been called on all .eh_frame |
| 1189 | input sections. It finalizes the size of .eh_frame_hdr section. */ |
| 1190 | |
| 1191 | bfd_boolean |
| 1192 | _bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 1193 | { |
| 1194 | struct elf_link_hash_table *htab; |
| 1195 | struct eh_frame_hdr_info *hdr_info; |
| 1196 | asection *sec; |
| 1197 | |
| 1198 | htab = elf_hash_table (info); |
| 1199 | hdr_info = &htab->eh_info; |
| 1200 | |
| 1201 | if (hdr_info->cies != NULL) |
| 1202 | { |
| 1203 | htab_delete (hdr_info->cies); |
| 1204 | hdr_info->cies = NULL; |
| 1205 | } |
| 1206 | |
| 1207 | sec = hdr_info->hdr_sec; |
| 1208 | if (sec == NULL) |
| 1209 | return FALSE; |
| 1210 | |
| 1211 | sec->size = EH_FRAME_HDR_SIZE; |
| 1212 | if (hdr_info->table) |
| 1213 | sec->size += 4 + hdr_info->fde_count * 8; |
| 1214 | |
| 1215 | elf_tdata (abfd)->eh_frame_hdr = sec; |
| 1216 | return TRUE; |
| 1217 | } |
| 1218 | |
| 1219 | /* This function is called from size_dynamic_sections. |
| 1220 | It needs to decide whether .eh_frame_hdr should be output or not, |
| 1221 | because when the dynamic symbol table has been sized it is too late |
| 1222 | to strip sections. */ |
| 1223 | |
| 1224 | bfd_boolean |
| 1225 | _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info) |
| 1226 | { |
| 1227 | asection *o; |
| 1228 | bfd *abfd; |
| 1229 | struct elf_link_hash_table *htab; |
| 1230 | struct eh_frame_hdr_info *hdr_info; |
| 1231 | |
| 1232 | htab = elf_hash_table (info); |
| 1233 | hdr_info = &htab->eh_info; |
| 1234 | if (hdr_info->hdr_sec == NULL) |
| 1235 | return TRUE; |
| 1236 | |
| 1237 | if (bfd_is_abs_section (hdr_info->hdr_sec->output_section)) |
| 1238 | { |
| 1239 | hdr_info->hdr_sec = NULL; |
| 1240 | return TRUE; |
| 1241 | } |
| 1242 | |
| 1243 | abfd = NULL; |
| 1244 | if (info->eh_frame_hdr) |
| 1245 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) |
| 1246 | { |
| 1247 | /* Count only sections which have at least a single CIE or FDE. |
| 1248 | There cannot be any CIE or FDE <= 8 bytes. */ |
| 1249 | o = bfd_get_section_by_name (abfd, ".eh_frame"); |
| 1250 | if (o && o->size > 8 && !bfd_is_abs_section (o->output_section)) |
| 1251 | break; |
| 1252 | } |
| 1253 | |
| 1254 | if (abfd == NULL) |
| 1255 | { |
| 1256 | hdr_info->hdr_sec->flags |= SEC_EXCLUDE; |
| 1257 | hdr_info->hdr_sec = NULL; |
| 1258 | return TRUE; |
| 1259 | } |
| 1260 | |
| 1261 | hdr_info->table = TRUE; |
| 1262 | return TRUE; |
| 1263 | } |
| 1264 | |
| 1265 | /* Adjust an address in the .eh_frame section. Given OFFSET within |
| 1266 | SEC, this returns the new offset in the adjusted .eh_frame section, |
| 1267 | or -1 if the address refers to a CIE/FDE which has been removed |
| 1268 | or to offset with dynamic relocation which is no longer needed. */ |
| 1269 | |
| 1270 | bfd_vma |
| 1271 | _bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, |
| 1272 | struct bfd_link_info *info, |
| 1273 | asection *sec, |
| 1274 | bfd_vma offset) |
| 1275 | { |
| 1276 | struct eh_frame_sec_info *sec_info; |
| 1277 | struct elf_link_hash_table *htab; |
| 1278 | struct eh_frame_hdr_info *hdr_info; |
| 1279 | unsigned int lo, hi, mid; |
| 1280 | |
| 1281 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 1282 | return offset; |
| 1283 | sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; |
| 1284 | |
| 1285 | if (offset >= sec->rawsize) |
| 1286 | return offset - sec->rawsize + sec->size; |
| 1287 | |
| 1288 | htab = elf_hash_table (info); |
| 1289 | hdr_info = &htab->eh_info; |
| 1290 | |
| 1291 | lo = 0; |
| 1292 | hi = sec_info->count; |
| 1293 | mid = 0; |
| 1294 | while (lo < hi) |
| 1295 | { |
| 1296 | mid = (lo + hi) / 2; |
| 1297 | if (offset < sec_info->entry[mid].offset) |
| 1298 | hi = mid; |
| 1299 | else if (offset |
| 1300 | >= sec_info->entry[mid].offset + sec_info->entry[mid].size) |
| 1301 | lo = mid + 1; |
| 1302 | else |
| 1303 | break; |
| 1304 | } |
| 1305 | |
| 1306 | BFD_ASSERT (lo < hi); |
| 1307 | |
| 1308 | /* FDE or CIE was removed. */ |
| 1309 | if (sec_info->entry[mid].removed) |
| 1310 | return (bfd_vma) -1; |
| 1311 | |
| 1312 | /* If converting personality pointers to DW_EH_PE_pcrel, there will be |
| 1313 | no need for run-time relocation against the personality field. */ |
| 1314 | if (sec_info->entry[mid].cie |
| 1315 | && sec_info->entry[mid].u.cie.make_per_encoding_relative |
| 1316 | && offset == (sec_info->entry[mid].offset + 8 |
| 1317 | + sec_info->entry[mid].u.cie.personality_offset)) |
| 1318 | return (bfd_vma) -2; |
| 1319 | |
| 1320 | /* If converting to DW_EH_PE_pcrel, there will be no need for run-time |
| 1321 | relocation against FDE's initial_location field. */ |
| 1322 | if (!sec_info->entry[mid].cie |
| 1323 | && sec_info->entry[mid].make_relative |
| 1324 | && offset == sec_info->entry[mid].offset + 8) |
| 1325 | return (bfd_vma) -2; |
| 1326 | |
| 1327 | /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need |
| 1328 | for run-time relocation against LSDA field. */ |
| 1329 | if (!sec_info->entry[mid].cie |
| 1330 | && sec_info->entry[mid].u.fde.cie_inf->u.cie.make_lsda_relative |
| 1331 | && offset == (sec_info->entry[mid].offset + 8 |
| 1332 | + sec_info->entry[mid].lsda_offset)) |
| 1333 | return (bfd_vma) -2; |
| 1334 | |
| 1335 | /* If converting to DW_EH_PE_pcrel, there will be no need for run-time |
| 1336 | relocation against DW_CFA_set_loc's arguments. */ |
| 1337 | if (sec_info->entry[mid].set_loc |
| 1338 | && sec_info->entry[mid].make_relative |
| 1339 | && (offset >= sec_info->entry[mid].offset + 8 |
| 1340 | + sec_info->entry[mid].set_loc[1])) |
| 1341 | { |
| 1342 | unsigned int cnt; |
| 1343 | |
| 1344 | for (cnt = 1; cnt <= sec_info->entry[mid].set_loc[0]; cnt++) |
| 1345 | if (offset == sec_info->entry[mid].offset + 8 |
| 1346 | + sec_info->entry[mid].set_loc[cnt]) |
| 1347 | return (bfd_vma) -2; |
| 1348 | } |
| 1349 | |
| 1350 | /* Any new augmentation bytes go before the first relocation. */ |
| 1351 | return (offset + sec_info->entry[mid].new_offset |
| 1352 | - sec_info->entry[mid].offset |
| 1353 | + extra_augmentation_string_bytes (sec_info->entry + mid) |
| 1354 | + extra_augmentation_data_bytes (sec_info->entry + mid)); |
| 1355 | } |
| 1356 | |
| 1357 | /* Write out .eh_frame section. This is called with the relocated |
| 1358 | contents. */ |
| 1359 | |
| 1360 | bfd_boolean |
| 1361 | _bfd_elf_write_section_eh_frame (bfd *abfd, |
| 1362 | struct bfd_link_info *info, |
| 1363 | asection *sec, |
| 1364 | bfd_byte *contents) |
| 1365 | { |
| 1366 | struct eh_frame_sec_info *sec_info; |
| 1367 | struct elf_link_hash_table *htab; |
| 1368 | struct eh_frame_hdr_info *hdr_info; |
| 1369 | unsigned int ptr_size; |
| 1370 | struct eh_cie_fde *ent; |
| 1371 | |
| 1372 | if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME) |
| 1373 | /* FIXME: octets_per_byte. */ |
| 1374 | return bfd_set_section_contents (abfd, sec->output_section, contents, |
| 1375 | sec->output_offset, sec->size); |
| 1376 | |
| 1377 | ptr_size = (get_elf_backend_data (abfd) |
| 1378 | ->elf_backend_eh_frame_address_size (abfd, sec)); |
| 1379 | BFD_ASSERT (ptr_size != 0); |
| 1380 | |
| 1381 | sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; |
| 1382 | htab = elf_hash_table (info); |
| 1383 | hdr_info = &htab->eh_info; |
| 1384 | |
| 1385 | if (hdr_info->table && hdr_info->array == NULL) |
| 1386 | hdr_info->array = (struct eh_frame_array_ent *) |
| 1387 | bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array)); |
| 1388 | if (hdr_info->array == NULL) |
| 1389 | hdr_info = NULL; |
| 1390 | |
| 1391 | /* The new offsets can be bigger or smaller than the original offsets. |
| 1392 | We therefore need to make two passes over the section: one backward |
| 1393 | pass to move entries up and one forward pass to move entries down. |
| 1394 | The two passes won't interfere with each other because entries are |
| 1395 | not reordered */ |
| 1396 | for (ent = sec_info->entry + sec_info->count; ent-- != sec_info->entry;) |
| 1397 | if (!ent->removed && ent->new_offset > ent->offset) |
| 1398 | memmove (contents + ent->new_offset, contents + ent->offset, ent->size); |
| 1399 | |
| 1400 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1401 | if (!ent->removed && ent->new_offset < ent->offset) |
| 1402 | memmove (contents + ent->new_offset, contents + ent->offset, ent->size); |
| 1403 | |
| 1404 | for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) |
| 1405 | { |
| 1406 | unsigned char *buf, *end; |
| 1407 | unsigned int new_size; |
| 1408 | |
| 1409 | if (ent->removed) |
| 1410 | continue; |
| 1411 | |
| 1412 | if (ent->size == 4) |
| 1413 | { |
| 1414 | /* Any terminating FDE must be at the end of the section. */ |
| 1415 | BFD_ASSERT (ent == sec_info->entry + sec_info->count - 1); |
| 1416 | continue; |
| 1417 | } |
| 1418 | |
| 1419 | buf = contents + ent->new_offset; |
| 1420 | end = buf + ent->size; |
| 1421 | new_size = size_of_output_cie_fde (ent, ptr_size); |
| 1422 | |
| 1423 | /* Update the size. It may be shrinked. */ |
| 1424 | bfd_put_32 (abfd, new_size - 4, buf); |
| 1425 | |
| 1426 | /* Filling the extra bytes with DW_CFA_nops. */ |
| 1427 | if (new_size != ent->size) |
| 1428 | memset (end, 0, new_size - ent->size); |
| 1429 | |
| 1430 | if (ent->cie) |
| 1431 | { |
| 1432 | /* CIE */ |
| 1433 | if (ent->make_relative |
| 1434 | || ent->u.cie.make_lsda_relative |
| 1435 | || ent->u.cie.per_encoding_relative) |
| 1436 | { |
| 1437 | char *aug; |
| 1438 | unsigned int action, extra_string, extra_data; |
| 1439 | unsigned int per_width, per_encoding; |
| 1440 | |
| 1441 | /* Need to find 'R' or 'L' augmentation's argument and modify |
| 1442 | DW_EH_PE_* value. */ |
| 1443 | action = ((ent->make_relative ? 1 : 0) |
| 1444 | | (ent->u.cie.make_lsda_relative ? 2 : 0) |
| 1445 | | (ent->u.cie.per_encoding_relative ? 4 : 0)); |
| 1446 | extra_string = extra_augmentation_string_bytes (ent); |
| 1447 | extra_data = extra_augmentation_data_bytes (ent); |
| 1448 | |
| 1449 | /* Skip length, id and version. */ |
| 1450 | buf += 9; |
| 1451 | aug = (char *) buf; |
| 1452 | buf += strlen (aug) + 1; |
| 1453 | skip_leb128 (&buf, end); |
| 1454 | skip_leb128 (&buf, end); |
| 1455 | skip_leb128 (&buf, end); |
| 1456 | if (*aug == 'z') |
| 1457 | { |
| 1458 | /* The uleb128 will always be a single byte for the kind |
| 1459 | of augmentation strings that we're prepared to handle. */ |
| 1460 | *buf++ += extra_data; |
| 1461 | aug++; |
| 1462 | } |
| 1463 | |
| 1464 | /* Make room for the new augmentation string and data bytes. */ |
| 1465 | memmove (buf + extra_string + extra_data, buf, end - buf); |
| 1466 | memmove (aug + extra_string, aug, buf - (bfd_byte *) aug); |
| 1467 | buf += extra_string; |
| 1468 | end += extra_string + extra_data; |
| 1469 | |
| 1470 | if (ent->add_augmentation_size) |
| 1471 | { |
| 1472 | *aug++ = 'z'; |
| 1473 | *buf++ = extra_data - 1; |
| 1474 | } |
| 1475 | if (ent->u.cie.add_fde_encoding) |
| 1476 | { |
| 1477 | BFD_ASSERT (action & 1); |
| 1478 | *aug++ = 'R'; |
| 1479 | *buf++ = make_pc_relative (DW_EH_PE_absptr, ptr_size); |
| 1480 | action &= ~1; |
| 1481 | } |
| 1482 | |
| 1483 | while (action) |
| 1484 | switch (*aug++) |
| 1485 | { |
| 1486 | case 'L': |
| 1487 | if (action & 2) |
| 1488 | { |
| 1489 | BFD_ASSERT (*buf == ent->lsda_encoding); |
| 1490 | *buf = make_pc_relative (*buf, ptr_size); |
| 1491 | action &= ~2; |
| 1492 | } |
| 1493 | buf++; |
| 1494 | break; |
| 1495 | case 'P': |
| 1496 | if (ent->u.cie.make_per_encoding_relative) |
| 1497 | *buf = make_pc_relative (*buf, ptr_size); |
| 1498 | per_encoding = *buf++; |
| 1499 | per_width = get_DW_EH_PE_width (per_encoding, ptr_size); |
| 1500 | BFD_ASSERT (per_width != 0); |
| 1501 | BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel) |
| 1502 | == ent->u.cie.per_encoding_relative); |
| 1503 | if ((per_encoding & 0x70) == DW_EH_PE_aligned) |
| 1504 | buf = (contents |
| 1505 | + ((buf - contents + per_width - 1) |
| 1506 | & ~((bfd_size_type) per_width - 1))); |
| 1507 | if (action & 4) |
| 1508 | { |
| 1509 | bfd_vma val; |
| 1510 | |
| 1511 | val = read_value (abfd, buf, per_width, |
| 1512 | get_DW_EH_PE_signed (per_encoding)); |
| 1513 | if (ent->u.cie.make_per_encoding_relative) |
| 1514 | val -= (sec->output_section->vma |
| 1515 | + sec->output_offset |
| 1516 | + (buf - contents)); |
| 1517 | else |
| 1518 | { |
| 1519 | val += (bfd_vma) ent->offset - ent->new_offset; |
| 1520 | val -= extra_string + extra_data; |
| 1521 | } |
| 1522 | write_value (abfd, buf, val, per_width); |
| 1523 | action &= ~4; |
| 1524 | } |
| 1525 | buf += per_width; |
| 1526 | break; |
| 1527 | case 'R': |
| 1528 | if (action & 1) |
| 1529 | { |
| 1530 | BFD_ASSERT (*buf == ent->fde_encoding); |
| 1531 | *buf = make_pc_relative (*buf, ptr_size); |
| 1532 | action &= ~1; |
| 1533 | } |
| 1534 | buf++; |
| 1535 | break; |
| 1536 | case 'S': |
| 1537 | break; |
| 1538 | default: |
| 1539 | BFD_FAIL (); |
| 1540 | } |
| 1541 | } |
| 1542 | } |
| 1543 | else |
| 1544 | { |
| 1545 | /* FDE */ |
| 1546 | bfd_vma value, address; |
| 1547 | unsigned int width; |
| 1548 | bfd_byte *start; |
| 1549 | struct eh_cie_fde *cie; |
| 1550 | |
| 1551 | /* Skip length. */ |
| 1552 | cie = ent->u.fde.cie_inf; |
| 1553 | buf += 4; |
| 1554 | value = ((ent->new_offset + sec->output_offset + 4) |
| 1555 | - (cie->new_offset + cie->u.cie.u.sec->output_offset)); |
| 1556 | bfd_put_32 (abfd, value, buf); |
| 1557 | buf += 4; |
| 1558 | width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); |
| 1559 | value = read_value (abfd, buf, width, |
| 1560 | get_DW_EH_PE_signed (ent->fde_encoding)); |
| 1561 | address = value; |
| 1562 | if (value) |
| 1563 | { |
| 1564 | switch (ent->fde_encoding & 0x70) |
| 1565 | { |
| 1566 | case DW_EH_PE_textrel: |
| 1567 | BFD_ASSERT (hdr_info == NULL); |
| 1568 | break; |
| 1569 | case DW_EH_PE_datarel: |
| 1570 | { |
| 1571 | asection *got = bfd_get_section_by_name (abfd, ".got"); |
| 1572 | |
| 1573 | BFD_ASSERT (got != NULL); |
| 1574 | address += got->vma; |
| 1575 | } |
| 1576 | break; |
| 1577 | case DW_EH_PE_pcrel: |
| 1578 | value += (bfd_vma) ent->offset - ent->new_offset; |
| 1579 | address += (sec->output_section->vma |
| 1580 | + sec->output_offset |
| 1581 | + ent->offset + 8); |
| 1582 | break; |
| 1583 | } |
| 1584 | if (ent->make_relative) |
| 1585 | value -= (sec->output_section->vma |
| 1586 | + sec->output_offset |
| 1587 | + ent->new_offset + 8); |
| 1588 | write_value (abfd, buf, value, width); |
| 1589 | } |
| 1590 | |
| 1591 | start = buf; |
| 1592 | |
| 1593 | if (hdr_info) |
| 1594 | { |
| 1595 | hdr_info->array[hdr_info->array_count].initial_loc = address; |
| 1596 | hdr_info->array[hdr_info->array_count++].fde |
| 1597 | = (sec->output_section->vma |
| 1598 | + sec->output_offset |
| 1599 | + ent->new_offset); |
| 1600 | } |
| 1601 | |
| 1602 | if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel |
| 1603 | || cie->u.cie.make_lsda_relative) |
| 1604 | { |
| 1605 | buf += ent->lsda_offset; |
| 1606 | width = get_DW_EH_PE_width (ent->lsda_encoding, ptr_size); |
| 1607 | value = read_value (abfd, buf, width, |
| 1608 | get_DW_EH_PE_signed (ent->lsda_encoding)); |
| 1609 | if (value) |
| 1610 | { |
| 1611 | if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel) |
| 1612 | value += (bfd_vma) ent->offset - ent->new_offset; |
| 1613 | else if (cie->u.cie.make_lsda_relative) |
| 1614 | value -= (sec->output_section->vma |
| 1615 | + sec->output_offset |
| 1616 | + ent->new_offset + 8 + ent->lsda_offset); |
| 1617 | write_value (abfd, buf, value, width); |
| 1618 | } |
| 1619 | } |
| 1620 | else if (ent->add_augmentation_size) |
| 1621 | { |
| 1622 | /* Skip the PC and length and insert a zero byte for the |
| 1623 | augmentation size. */ |
| 1624 | buf += width * 2; |
| 1625 | memmove (buf + 1, buf, end - buf); |
| 1626 | *buf = 0; |
| 1627 | } |
| 1628 | |
| 1629 | if (ent->set_loc) |
| 1630 | { |
| 1631 | /* Adjust DW_CFA_set_loc. */ |
| 1632 | unsigned int cnt; |
| 1633 | bfd_vma new_offset; |
| 1634 | |
| 1635 | width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); |
| 1636 | new_offset = ent->new_offset + 8 |
| 1637 | + extra_augmentation_string_bytes (ent) |
| 1638 | + extra_augmentation_data_bytes (ent); |
| 1639 | |
| 1640 | for (cnt = 1; cnt <= ent->set_loc[0]; cnt++) |
| 1641 | { |
| 1642 | buf = start + ent->set_loc[cnt]; |
| 1643 | |
| 1644 | value = read_value (abfd, buf, width, |
| 1645 | get_DW_EH_PE_signed (ent->fde_encoding)); |
| 1646 | if (!value) |
| 1647 | continue; |
| 1648 | |
| 1649 | if ((ent->fde_encoding & 0x70) == DW_EH_PE_pcrel) |
| 1650 | value += (bfd_vma) ent->offset + 8 - new_offset; |
| 1651 | if (ent->make_relative) |
| 1652 | value -= (sec->output_section->vma |
| 1653 | + sec->output_offset |
| 1654 | + new_offset + ent->set_loc[cnt]); |
| 1655 | write_value (abfd, buf, value, width); |
| 1656 | } |
| 1657 | } |
| 1658 | } |
| 1659 | } |
| 1660 | |
| 1661 | /* We don't align the section to its section alignment since the |
| 1662 | runtime library only expects all CIE/FDE records aligned at |
| 1663 | the pointer size. _bfd_elf_discard_section_eh_frame should |
| 1664 | have padded CIE/FDE records to multiple of pointer size with |
| 1665 | size_of_output_cie_fde. */ |
| 1666 | if ((sec->size % ptr_size) != 0) |
| 1667 | abort (); |
| 1668 | |
| 1669 | /* FIXME: octets_per_byte. */ |
| 1670 | return bfd_set_section_contents (abfd, sec->output_section, |
| 1671 | contents, (file_ptr) sec->output_offset, |
| 1672 | sec->size); |
| 1673 | } |
| 1674 | |
| 1675 | /* Helper function used to sort .eh_frame_hdr search table by increasing |
| 1676 | VMA of FDE initial location. */ |
| 1677 | |
| 1678 | static int |
| 1679 | vma_compare (const void *a, const void *b) |
| 1680 | { |
| 1681 | const struct eh_frame_array_ent *p = (const struct eh_frame_array_ent *) a; |
| 1682 | const struct eh_frame_array_ent *q = (const struct eh_frame_array_ent *) b; |
| 1683 | if (p->initial_loc > q->initial_loc) |
| 1684 | return 1; |
| 1685 | if (p->initial_loc < q->initial_loc) |
| 1686 | return -1; |
| 1687 | return 0; |
| 1688 | } |
| 1689 | |
| 1690 | /* Write out .eh_frame_hdr section. This must be called after |
| 1691 | _bfd_elf_write_section_eh_frame has been called on all input |
| 1692 | .eh_frame sections. |
| 1693 | .eh_frame_hdr format: |
| 1694 | ubyte version (currently 1) |
| 1695 | ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of |
| 1696 | .eh_frame section) |
| 1697 | ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count |
| 1698 | number (or DW_EH_PE_omit if there is no |
| 1699 | binary search table computed)) |
| 1700 | ubyte table_enc (DW_EH_PE_* encoding of binary search table, |
| 1701 | or DW_EH_PE_omit if not present. |
| 1702 | DW_EH_PE_datarel is using address of |
| 1703 | .eh_frame_hdr section start as base) |
| 1704 | [encoded] eh_frame_ptr (pointer to start of .eh_frame section) |
| 1705 | optionally followed by: |
| 1706 | [encoded] fde_count (total number of FDEs in .eh_frame section) |
| 1707 | fde_count x [encoded] initial_loc, fde |
| 1708 | (array of encoded pairs containing |
| 1709 | FDE initial_location field and FDE address, |
| 1710 | sorted by increasing initial_loc). */ |
| 1711 | |
| 1712 | bfd_boolean |
| 1713 | _bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) |
| 1714 | { |
| 1715 | struct elf_link_hash_table *htab; |
| 1716 | struct eh_frame_hdr_info *hdr_info; |
| 1717 | asection *sec; |
| 1718 | bfd_byte *contents; |
| 1719 | asection *eh_frame_sec; |
| 1720 | bfd_size_type size; |
| 1721 | bfd_boolean retval; |
| 1722 | bfd_vma encoded_eh_frame; |
| 1723 | |
| 1724 | htab = elf_hash_table (info); |
| 1725 | hdr_info = &htab->eh_info; |
| 1726 | sec = hdr_info->hdr_sec; |
| 1727 | if (sec == NULL) |
| 1728 | return TRUE; |
| 1729 | |
| 1730 | size = EH_FRAME_HDR_SIZE; |
| 1731 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
| 1732 | size += 4 + hdr_info->fde_count * 8; |
| 1733 | contents = (bfd_byte *) bfd_malloc (size); |
| 1734 | if (contents == NULL) |
| 1735 | return FALSE; |
| 1736 | |
| 1737 | eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame"); |
| 1738 | if (eh_frame_sec == NULL) |
| 1739 | { |
| 1740 | free (contents); |
| 1741 | return FALSE; |
| 1742 | } |
| 1743 | |
| 1744 | memset (contents, 0, EH_FRAME_HDR_SIZE); |
| 1745 | contents[0] = 1; /* Version. */ |
| 1746 | contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address |
| 1747 | (abfd, info, eh_frame_sec, 0, sec, 4, |
| 1748 | &encoded_eh_frame); /* .eh_frame offset. */ |
| 1749 | |
| 1750 | if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) |
| 1751 | { |
| 1752 | contents[2] = DW_EH_PE_udata4; /* FDE count encoding. */ |
| 1753 | contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; /* Search table enc. */ |
| 1754 | } |
| 1755 | else |
| 1756 | { |
| 1757 | contents[2] = DW_EH_PE_omit; |
| 1758 | contents[3] = DW_EH_PE_omit; |
| 1759 | } |
| 1760 | bfd_put_32 (abfd, encoded_eh_frame, contents + 4); |
| 1761 | |
| 1762 | if (contents[2] != DW_EH_PE_omit) |
| 1763 | { |
| 1764 | unsigned int i; |
| 1765 | |
| 1766 | bfd_put_32 (abfd, hdr_info->fde_count, contents + EH_FRAME_HDR_SIZE); |
| 1767 | qsort (hdr_info->array, hdr_info->fde_count, sizeof (*hdr_info->array), |
| 1768 | vma_compare); |
| 1769 | for (i = 0; i < hdr_info->fde_count; i++) |
| 1770 | { |
| 1771 | bfd_put_32 (abfd, |
| 1772 | hdr_info->array[i].initial_loc |
| 1773 | - sec->output_section->vma, |
| 1774 | contents + EH_FRAME_HDR_SIZE + i * 8 + 4); |
| 1775 | bfd_put_32 (abfd, |
| 1776 | hdr_info->array[i].fde - sec->output_section->vma, |
| 1777 | contents + EH_FRAME_HDR_SIZE + i * 8 + 8); |
| 1778 | } |
| 1779 | } |
| 1780 | |
| 1781 | /* FIXME: octets_per_byte. */ |
| 1782 | retval = bfd_set_section_contents (abfd, sec->output_section, |
| 1783 | contents, (file_ptr) sec->output_offset, |
| 1784 | sec->size); |
| 1785 | free (contents); |
| 1786 | return retval; |
| 1787 | } |
| 1788 | |
| 1789 | /* Return the width of FDE addresses. This is the default implementation. */ |
| 1790 | |
| 1791 | unsigned int |
| 1792 | _bfd_elf_eh_frame_address_size (bfd *abfd, asection *sec ATTRIBUTE_UNUSED) |
| 1793 | { |
| 1794 | return elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64 ? 8 : 4; |
| 1795 | } |
| 1796 | |
| 1797 | /* Decide whether we can use a PC-relative encoding within the given |
| 1798 | EH frame section. This is the default implementation. */ |
| 1799 | |
| 1800 | bfd_boolean |
| 1801 | _bfd_elf_can_make_relative (bfd *input_bfd ATTRIBUTE_UNUSED, |
| 1802 | struct bfd_link_info *info ATTRIBUTE_UNUSED, |
| 1803 | asection *eh_frame_section ATTRIBUTE_UNUSED) |
| 1804 | { |
| 1805 | return TRUE; |
| 1806 | } |
| 1807 | |
| 1808 | /* Select an encoding for the given address. Preference is given to |
| 1809 | PC-relative addressing modes. */ |
| 1810 | |
| 1811 | bfd_byte |
| 1812 | _bfd_elf_encode_eh_address (bfd *abfd ATTRIBUTE_UNUSED, |
| 1813 | struct bfd_link_info *info ATTRIBUTE_UNUSED, |
| 1814 | asection *osec, bfd_vma offset, |
| 1815 | asection *loc_sec, bfd_vma loc_offset, |
| 1816 | bfd_vma *encoded) |
| 1817 | { |
| 1818 | *encoded = osec->vma + offset - |
| 1819 | (loc_sec->output_section->vma + loc_sec->output_offset + loc_offset); |
| 1820 | return DW_EH_PE_pcrel | DW_EH_PE_sdata4; |
| 1821 | } |