| 1 | /* Read ELF (Executable and Linking Format) object files for GDB. |
| 2 | |
| 3 | Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, |
| 4 | 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
| 5 | Free Software Foundation, Inc. |
| 6 | |
| 7 | Written by Fred Fish at Cygnus Support. |
| 8 | |
| 9 | This file is part of GDB. |
| 10 | |
| 11 | This program is free software; you can redistribute it and/or modify |
| 12 | it under the terms of the GNU General Public License as published by |
| 13 | the Free Software Foundation; either version 3 of the License, or |
| 14 | (at your option) any later version. |
| 15 | |
| 16 | This program is distributed in the hope that it will be useful, |
| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | GNU General Public License for more details. |
| 20 | |
| 21 | You should have received a copy of the GNU General Public License |
| 22 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "bfd.h" |
| 26 | #include "gdb_string.h" |
| 27 | #include "elf-bfd.h" |
| 28 | #include "elf/common.h" |
| 29 | #include "elf/internal.h" |
| 30 | #include "elf/mips.h" |
| 31 | #include "symtab.h" |
| 32 | #include "symfile.h" |
| 33 | #include "objfiles.h" |
| 34 | #include "buildsym.h" |
| 35 | #include "stabsread.h" |
| 36 | #include "gdb-stabs.h" |
| 37 | #include "complaints.h" |
| 38 | #include "demangle.h" |
| 39 | |
| 40 | extern void _initialize_elfread (void); |
| 41 | |
| 42 | /* The struct elfinfo is available only during ELF symbol table and |
| 43 | psymtab reading. It is destroyed at the completion of psymtab-reading. |
| 44 | It's local to elf_symfile_read. */ |
| 45 | |
| 46 | struct elfinfo |
| 47 | { |
| 48 | asection *stabsect; /* Section pointer for .stab section */ |
| 49 | asection *stabindexsect; /* Section pointer for .stab.index section */ |
| 50 | asection *mdebugsect; /* Section pointer for .mdebug section */ |
| 51 | }; |
| 52 | |
| 53 | static void free_elfinfo (void *); |
| 54 | |
| 55 | /* Locate the segments in ABFD. */ |
| 56 | |
| 57 | static struct symfile_segment_data * |
| 58 | elf_symfile_segments (bfd *abfd) |
| 59 | { |
| 60 | Elf_Internal_Phdr *phdrs, **segments; |
| 61 | long phdrs_size; |
| 62 | int num_phdrs, num_segments, num_sections, i; |
| 63 | asection *sect; |
| 64 | struct symfile_segment_data *data; |
| 65 | |
| 66 | phdrs_size = bfd_get_elf_phdr_upper_bound (abfd); |
| 67 | if (phdrs_size == -1) |
| 68 | return NULL; |
| 69 | |
| 70 | phdrs = alloca (phdrs_size); |
| 71 | num_phdrs = bfd_get_elf_phdrs (abfd, phdrs); |
| 72 | if (num_phdrs == -1) |
| 73 | return NULL; |
| 74 | |
| 75 | num_segments = 0; |
| 76 | segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs); |
| 77 | for (i = 0; i < num_phdrs; i++) |
| 78 | if (phdrs[i].p_type == PT_LOAD) |
| 79 | segments[num_segments++] = &phdrs[i]; |
| 80 | |
| 81 | if (num_segments == 0) |
| 82 | return NULL; |
| 83 | |
| 84 | data = XZALLOC (struct symfile_segment_data); |
| 85 | data->num_segments = num_segments; |
| 86 | data->segment_bases = XCALLOC (num_segments, CORE_ADDR); |
| 87 | data->segment_sizes = XCALLOC (num_segments, CORE_ADDR); |
| 88 | |
| 89 | for (i = 0; i < num_segments; i++) |
| 90 | { |
| 91 | data->segment_bases[i] = segments[i]->p_vaddr; |
| 92 | data->segment_sizes[i] = segments[i]->p_memsz; |
| 93 | } |
| 94 | |
| 95 | num_sections = bfd_count_sections (abfd); |
| 96 | data->segment_info = XCALLOC (num_sections, int); |
| 97 | |
| 98 | for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next) |
| 99 | { |
| 100 | int j; |
| 101 | CORE_ADDR vma; |
| 102 | |
| 103 | if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) |
| 104 | continue; |
| 105 | |
| 106 | vma = bfd_get_section_vma (abfd, sect); |
| 107 | |
| 108 | for (j = 0; j < num_segments; j++) |
| 109 | if (segments[j]->p_memsz > 0 |
| 110 | && vma >= segments[j]->p_vaddr |
| 111 | && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz) |
| 112 | { |
| 113 | data->segment_info[i] = j + 1; |
| 114 | break; |
| 115 | } |
| 116 | |
| 117 | /* We should have found a segment for every non-empty section. |
| 118 | If we haven't, we will not relocate this section by any |
| 119 | offsets we apply to the segments. As an exception, do not |
| 120 | warn about SHT_NOBITS sections; in normal ELF execution |
| 121 | environments, SHT_NOBITS means zero-initialized and belongs |
| 122 | in a segment, but in no-OS environments some tools (e.g. ARM |
| 123 | RealView) use SHT_NOBITS for uninitialized data. Since it is |
| 124 | uninitialized, it doesn't need a program header. Such |
| 125 | binaries are not relocatable. */ |
| 126 | if (bfd_get_section_size (sect) > 0 && j == num_segments |
| 127 | && (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0) |
| 128 | warning (_("Loadable segment \"%s\" outside of ELF segments"), |
| 129 | bfd_section_name (abfd, sect)); |
| 130 | } |
| 131 | |
| 132 | return data; |
| 133 | } |
| 134 | |
| 135 | /* We are called once per section from elf_symfile_read. We |
| 136 | need to examine each section we are passed, check to see |
| 137 | if it is something we are interested in processing, and |
| 138 | if so, stash away some access information for the section. |
| 139 | |
| 140 | For now we recognize the dwarf debug information sections and |
| 141 | line number sections from matching their section names. The |
| 142 | ELF definition is no real help here since it has no direct |
| 143 | knowledge of DWARF (by design, so any debugging format can be |
| 144 | used). |
| 145 | |
| 146 | We also recognize the ".stab" sections used by the Sun compilers |
| 147 | released with Solaris 2. |
| 148 | |
| 149 | FIXME: The section names should not be hardwired strings (what |
| 150 | should they be? I don't think most object file formats have enough |
| 151 | section flags to specify what kind of debug section it is |
| 152 | -kingdon). */ |
| 153 | |
| 154 | static void |
| 155 | elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip) |
| 156 | { |
| 157 | struct elfinfo *ei; |
| 158 | |
| 159 | ei = (struct elfinfo *) eip; |
| 160 | if (strcmp (sectp->name, ".stab") == 0) |
| 161 | { |
| 162 | ei->stabsect = sectp; |
| 163 | } |
| 164 | else if (strcmp (sectp->name, ".stab.index") == 0) |
| 165 | { |
| 166 | ei->stabindexsect = sectp; |
| 167 | } |
| 168 | else if (strcmp (sectp->name, ".mdebug") == 0) |
| 169 | { |
| 170 | ei->mdebugsect = sectp; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | static struct minimal_symbol * |
| 175 | record_minimal_symbol (const char *name, int name_len, int copy_name, |
| 176 | CORE_ADDR address, |
| 177 | enum minimal_symbol_type ms_type, |
| 178 | asection *bfd_section, struct objfile *objfile) |
| 179 | { |
| 180 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
| 181 | |
| 182 | if (ms_type == mst_text || ms_type == mst_file_text) |
| 183 | address = gdbarch_smash_text_address (gdbarch, address); |
| 184 | |
| 185 | return prim_record_minimal_symbol_full (name, name_len, copy_name, address, |
| 186 | ms_type, bfd_section->index, |
| 187 | bfd_section, objfile); |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | |
| 192 | LOCAL FUNCTION |
| 193 | |
| 194 | elf_symtab_read -- read the symbol table of an ELF file |
| 195 | |
| 196 | SYNOPSIS |
| 197 | |
| 198 | void elf_symtab_read (struct objfile *objfile, int type, |
| 199 | long number_of_symbols, asymbol **symbol_table) |
| 200 | |
| 201 | DESCRIPTION |
| 202 | |
| 203 | Given an objfile, a symbol table, and a flag indicating whether the |
| 204 | symbol table contains regular, dynamic, or synthetic symbols, add all |
| 205 | the global function and data symbols to the minimal symbol table. |
| 206 | |
| 207 | In stabs-in-ELF, as implemented by Sun, there are some local symbols |
| 208 | defined in the ELF symbol table, which can be used to locate |
| 209 | the beginnings of sections from each ".o" file that was linked to |
| 210 | form the executable objfile. We gather any such info and record it |
| 211 | in data structures hung off the objfile's private data. |
| 212 | |
| 213 | */ |
| 214 | |
| 215 | #define ST_REGULAR 0 |
| 216 | #define ST_DYNAMIC 1 |
| 217 | #define ST_SYNTHETIC 2 |
| 218 | |
| 219 | static void |
| 220 | elf_symtab_read (struct objfile *objfile, int type, |
| 221 | long number_of_symbols, asymbol **symbol_table, |
| 222 | int copy_names) |
| 223 | { |
| 224 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
| 225 | long storage_needed; |
| 226 | asymbol *sym; |
| 227 | long i; |
| 228 | CORE_ADDR symaddr; |
| 229 | CORE_ADDR offset; |
| 230 | enum minimal_symbol_type ms_type; |
| 231 | /* If sectinfo is nonNULL, it contains section info that should end up |
| 232 | filed in the objfile. */ |
| 233 | struct stab_section_info *sectinfo = NULL; |
| 234 | /* If filesym is nonzero, it points to a file symbol, but we haven't |
| 235 | seen any section info for it yet. */ |
| 236 | asymbol *filesym = 0; |
| 237 | /* Name of filesym. This is either a constant string or is saved on |
| 238 | the objfile's obstack. */ |
| 239 | char *filesymname = ""; |
| 240 | struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; |
| 241 | int stripped = (bfd_get_symcount (objfile->obfd) == 0); |
| 242 | |
| 243 | for (i = 0; i < number_of_symbols; i++) |
| 244 | { |
| 245 | sym = symbol_table[i]; |
| 246 | if (sym->name == NULL || *sym->name == '\0') |
| 247 | { |
| 248 | /* Skip names that don't exist (shouldn't happen), or names |
| 249 | that are null strings (may happen). */ |
| 250 | continue; |
| 251 | } |
| 252 | |
| 253 | /* Skip "special" symbols, e.g. ARM mapping symbols. These are |
| 254 | symbols which do not correspond to objects in the symbol table, |
| 255 | but have some other target-specific meaning. */ |
| 256 | if (bfd_is_target_special_symbol (objfile->obfd, sym)) |
| 257 | { |
| 258 | if (gdbarch_record_special_symbol_p (gdbarch)) |
| 259 | gdbarch_record_special_symbol (gdbarch, objfile, sym); |
| 260 | continue; |
| 261 | } |
| 262 | |
| 263 | offset = ANOFFSET (objfile->section_offsets, sym->section->index); |
| 264 | if (type == ST_DYNAMIC |
| 265 | && sym->section == &bfd_und_section |
| 266 | && (sym->flags & BSF_FUNCTION)) |
| 267 | { |
| 268 | struct minimal_symbol *msym; |
| 269 | bfd *abfd = objfile->obfd; |
| 270 | asection *sect; |
| 271 | |
| 272 | /* Symbol is a reference to a function defined in |
| 273 | a shared library. |
| 274 | If its value is non zero then it is usually the address |
| 275 | of the corresponding entry in the procedure linkage table, |
| 276 | plus the desired section offset. |
| 277 | If its value is zero then the dynamic linker has to resolve |
| 278 | the symbol. We are unable to find any meaningful address |
| 279 | for this symbol in the executable file, so we skip it. */ |
| 280 | symaddr = sym->value; |
| 281 | if (symaddr == 0) |
| 282 | continue; |
| 283 | |
| 284 | /* sym->section is the undefined section. However, we want to |
| 285 | record the section where the PLT stub resides with the |
| 286 | minimal symbol. Search the section table for the one that |
| 287 | covers the stub's address. */ |
| 288 | for (sect = abfd->sections; sect != NULL; sect = sect->next) |
| 289 | { |
| 290 | if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) |
| 291 | continue; |
| 292 | |
| 293 | if (symaddr >= bfd_get_section_vma (abfd, sect) |
| 294 | && symaddr < bfd_get_section_vma (abfd, sect) |
| 295 | + bfd_get_section_size (sect)) |
| 296 | break; |
| 297 | } |
| 298 | if (!sect) |
| 299 | continue; |
| 300 | |
| 301 | symaddr += ANOFFSET (objfile->section_offsets, sect->index); |
| 302 | |
| 303 | msym = record_minimal_symbol |
| 304 | (sym->name, strlen (sym->name), copy_names, |
| 305 | symaddr, mst_solib_trampoline, sect, objfile); |
| 306 | if (msym != NULL) |
| 307 | msym->filename = filesymname; |
| 308 | continue; |
| 309 | } |
| 310 | |
| 311 | /* If it is a nonstripped executable, do not enter dynamic |
| 312 | symbols, as the dynamic symbol table is usually a subset |
| 313 | of the main symbol table. */ |
| 314 | if (type == ST_DYNAMIC && !stripped) |
| 315 | continue; |
| 316 | if (sym->flags & BSF_FILE) |
| 317 | { |
| 318 | /* STT_FILE debugging symbol that helps stabs-in-elf debugging. |
| 319 | Chain any old one onto the objfile; remember new sym. */ |
| 320 | if (sectinfo != NULL) |
| 321 | { |
| 322 | sectinfo->next = dbx->stab_section_info; |
| 323 | dbx->stab_section_info = sectinfo; |
| 324 | sectinfo = NULL; |
| 325 | } |
| 326 | filesym = sym; |
| 327 | filesymname = |
| 328 | obsavestring ((char *) filesym->name, strlen (filesym->name), |
| 329 | &objfile->objfile_obstack); |
| 330 | } |
| 331 | else if (sym->flags & BSF_SECTION_SYM) |
| 332 | continue; |
| 333 | else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) |
| 334 | { |
| 335 | struct minimal_symbol *msym; |
| 336 | |
| 337 | /* Select global/local/weak symbols. Note that bfd puts abs |
| 338 | symbols in their own section, so all symbols we are |
| 339 | interested in will have a section. */ |
| 340 | /* Bfd symbols are section relative. */ |
| 341 | symaddr = sym->value + sym->section->vma; |
| 342 | /* Relocate all non-absolute and non-TLS symbols by the |
| 343 | section offset. */ |
| 344 | if (sym->section != &bfd_abs_section |
| 345 | && !(sym->section->flags & SEC_THREAD_LOCAL)) |
| 346 | { |
| 347 | symaddr += offset; |
| 348 | } |
| 349 | /* For non-absolute symbols, use the type of the section |
| 350 | they are relative to, to intuit text/data. Bfd provides |
| 351 | no way of figuring this out for absolute symbols. */ |
| 352 | if (sym->section == &bfd_abs_section) |
| 353 | { |
| 354 | /* This is a hack to get the minimal symbol type |
| 355 | right for Irix 5, which has absolute addresses |
| 356 | with special section indices for dynamic symbols. |
| 357 | |
| 358 | NOTE: uweigand-20071112: Synthetic symbols do not |
| 359 | have an ELF-private part, so do not touch those. */ |
| 360 | unsigned int shndx = type == ST_SYNTHETIC ? 0 : |
| 361 | ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; |
| 362 | |
| 363 | switch (shndx) |
| 364 | { |
| 365 | case SHN_MIPS_TEXT: |
| 366 | ms_type = mst_text; |
| 367 | break; |
| 368 | case SHN_MIPS_DATA: |
| 369 | ms_type = mst_data; |
| 370 | break; |
| 371 | case SHN_MIPS_ACOMMON: |
| 372 | ms_type = mst_bss; |
| 373 | break; |
| 374 | default: |
| 375 | ms_type = mst_abs; |
| 376 | } |
| 377 | |
| 378 | /* If it is an Irix dynamic symbol, skip section name |
| 379 | symbols, relocate all others by section offset. */ |
| 380 | if (ms_type != mst_abs) |
| 381 | { |
| 382 | if (sym->name[0] == '.') |
| 383 | continue; |
| 384 | symaddr += offset; |
| 385 | } |
| 386 | } |
| 387 | else if (sym->section->flags & SEC_CODE) |
| 388 | { |
| 389 | if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) |
| 390 | { |
| 391 | ms_type = mst_text; |
| 392 | } |
| 393 | else if ((sym->name[0] == '.' && sym->name[1] == 'L') |
| 394 | || ((sym->flags & BSF_LOCAL) |
| 395 | && sym->name[0] == '$' |
| 396 | && sym->name[1] == 'L')) |
| 397 | /* Looks like a compiler-generated label. Skip |
| 398 | it. The assembler should be skipping these (to |
| 399 | keep executables small), but apparently with |
| 400 | gcc on the (deleted) delta m88k SVR4, it loses. |
| 401 | So to have us check too should be harmless (but |
| 402 | I encourage people to fix this in the assembler |
| 403 | instead of adding checks here). */ |
| 404 | continue; |
| 405 | else |
| 406 | { |
| 407 | ms_type = mst_file_text; |
| 408 | } |
| 409 | } |
| 410 | else if (sym->section->flags & SEC_ALLOC) |
| 411 | { |
| 412 | if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) |
| 413 | { |
| 414 | if (sym->section->flags & SEC_LOAD) |
| 415 | { |
| 416 | ms_type = mst_data; |
| 417 | } |
| 418 | else |
| 419 | { |
| 420 | ms_type = mst_bss; |
| 421 | } |
| 422 | } |
| 423 | else if (sym->flags & BSF_LOCAL) |
| 424 | { |
| 425 | /* Named Local variable in a Data section. |
| 426 | Check its name for stabs-in-elf. */ |
| 427 | int special_local_sect; |
| 428 | if (strcmp ("Bbss.bss", sym->name) == 0) |
| 429 | special_local_sect = SECT_OFF_BSS (objfile); |
| 430 | else if (strcmp ("Ddata.data", sym->name) == 0) |
| 431 | special_local_sect = SECT_OFF_DATA (objfile); |
| 432 | else if (strcmp ("Drodata.rodata", sym->name) == 0) |
| 433 | special_local_sect = SECT_OFF_RODATA (objfile); |
| 434 | else |
| 435 | special_local_sect = -1; |
| 436 | if (special_local_sect >= 0) |
| 437 | { |
| 438 | /* Found a special local symbol. Allocate a |
| 439 | sectinfo, if needed, and fill it in. */ |
| 440 | if (sectinfo == NULL) |
| 441 | { |
| 442 | int max_index; |
| 443 | size_t size; |
| 444 | |
| 445 | max_index = SECT_OFF_BSS (objfile); |
| 446 | if (objfile->sect_index_data > max_index) |
| 447 | max_index = objfile->sect_index_data; |
| 448 | if (objfile->sect_index_rodata > max_index) |
| 449 | max_index = objfile->sect_index_rodata; |
| 450 | |
| 451 | /* max_index is the largest index we'll |
| 452 | use into this array, so we must |
| 453 | allocate max_index+1 elements for it. |
| 454 | However, 'struct stab_section_info' |
| 455 | already includes one element, so we |
| 456 | need to allocate max_index aadditional |
| 457 | elements. */ |
| 458 | size = (sizeof (struct stab_section_info) |
| 459 | + (sizeof (CORE_ADDR) |
| 460 | * max_index)); |
| 461 | sectinfo = (struct stab_section_info *) |
| 462 | xmalloc (size); |
| 463 | memset (sectinfo, 0, size); |
| 464 | sectinfo->num_sections = max_index; |
| 465 | if (filesym == NULL) |
| 466 | { |
| 467 | complaint (&symfile_complaints, |
| 468 | _("elf/stab section information %s without a preceding file symbol"), |
| 469 | sym->name); |
| 470 | } |
| 471 | else |
| 472 | { |
| 473 | sectinfo->filename = |
| 474 | (char *) filesym->name; |
| 475 | } |
| 476 | } |
| 477 | if (sectinfo->sections[special_local_sect] != 0) |
| 478 | complaint (&symfile_complaints, |
| 479 | _("duplicated elf/stab section information for %s"), |
| 480 | sectinfo->filename); |
| 481 | /* BFD symbols are section relative. */ |
| 482 | symaddr = sym->value + sym->section->vma; |
| 483 | /* Relocate non-absolute symbols by the |
| 484 | section offset. */ |
| 485 | if (sym->section != &bfd_abs_section) |
| 486 | symaddr += offset; |
| 487 | sectinfo->sections[special_local_sect] = symaddr; |
| 488 | /* The special local symbols don't go in the |
| 489 | minimal symbol table, so ignore this one. */ |
| 490 | continue; |
| 491 | } |
| 492 | /* Not a special stabs-in-elf symbol, do regular |
| 493 | symbol processing. */ |
| 494 | if (sym->section->flags & SEC_LOAD) |
| 495 | { |
| 496 | ms_type = mst_file_data; |
| 497 | } |
| 498 | else |
| 499 | { |
| 500 | ms_type = mst_file_bss; |
| 501 | } |
| 502 | } |
| 503 | else |
| 504 | { |
| 505 | ms_type = mst_unknown; |
| 506 | } |
| 507 | } |
| 508 | else |
| 509 | { |
| 510 | /* FIXME: Solaris2 shared libraries include lots of |
| 511 | odd "absolute" and "undefined" symbols, that play |
| 512 | hob with actions like finding what function the PC |
| 513 | is in. Ignore them if they aren't text, data, or bss. */ |
| 514 | /* ms_type = mst_unknown; */ |
| 515 | continue; /* Skip this symbol. */ |
| 516 | } |
| 517 | msym = record_minimal_symbol |
| 518 | (sym->name, strlen (sym->name), copy_names, symaddr, |
| 519 | ms_type, sym->section, objfile); |
| 520 | |
| 521 | if (msym) |
| 522 | { |
| 523 | /* Pass symbol size field in via BFD. FIXME!!! */ |
| 524 | elf_symbol_type *elf_sym; |
| 525 | |
| 526 | /* NOTE: uweigand-20071112: A synthetic symbol does not have an |
| 527 | ELF-private part. However, in some cases (e.g. synthetic |
| 528 | 'dot' symbols on ppc64) the udata.p entry is set to point back |
| 529 | to the original ELF symbol it was derived from. Get the size |
| 530 | from that symbol. */ |
| 531 | if (type != ST_SYNTHETIC) |
| 532 | elf_sym = (elf_symbol_type *) sym; |
| 533 | else |
| 534 | elf_sym = (elf_symbol_type *) sym->udata.p; |
| 535 | |
| 536 | if (elf_sym) |
| 537 | MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size; |
| 538 | |
| 539 | msym->filename = filesymname; |
| 540 | gdbarch_elf_make_msymbol_special (gdbarch, sym, msym); |
| 541 | } |
| 542 | |
| 543 | /* For @plt symbols, also record a trampoline to the |
| 544 | destination symbol. The @plt symbol will be used in |
| 545 | disassembly, and the trampoline will be used when we are |
| 546 | trying to find the target. */ |
| 547 | if (msym && ms_type == mst_text && type == ST_SYNTHETIC) |
| 548 | { |
| 549 | int len = strlen (sym->name); |
| 550 | |
| 551 | if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0) |
| 552 | { |
| 553 | struct minimal_symbol *mtramp; |
| 554 | |
| 555 | mtramp = record_minimal_symbol (sym->name, len - 4, 1, |
| 556 | symaddr, |
| 557 | mst_solib_trampoline, |
| 558 | sym->section, objfile); |
| 559 | if (mtramp) |
| 560 | { |
| 561 | MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym); |
| 562 | mtramp->filename = filesymname; |
| 563 | gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp); |
| 564 | } |
| 565 | } |
| 566 | } |
| 567 | } |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | struct build_id |
| 572 | { |
| 573 | size_t size; |
| 574 | gdb_byte data[1]; |
| 575 | }; |
| 576 | |
| 577 | /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */ |
| 578 | |
| 579 | static struct build_id * |
| 580 | build_id_bfd_get (bfd *abfd) |
| 581 | { |
| 582 | struct build_id *retval; |
| 583 | |
| 584 | if (!bfd_check_format (abfd, bfd_object) |
| 585 | || bfd_get_flavour (abfd) != bfd_target_elf_flavour |
| 586 | || elf_tdata (abfd)->build_id == NULL) |
| 587 | return NULL; |
| 588 | |
| 589 | retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size); |
| 590 | retval->size = elf_tdata (abfd)->build_id_size; |
| 591 | memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size); |
| 592 | |
| 593 | return retval; |
| 594 | } |
| 595 | |
| 596 | /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */ |
| 597 | |
| 598 | static int |
| 599 | build_id_verify (const char *filename, struct build_id *check) |
| 600 | { |
| 601 | bfd *abfd; |
| 602 | struct build_id *found = NULL; |
| 603 | int retval = 0; |
| 604 | |
| 605 | /* We expect to be silent on the non-existing files. */ |
| 606 | abfd = bfd_open_maybe_remote (filename); |
| 607 | if (abfd == NULL) |
| 608 | return 0; |
| 609 | |
| 610 | found = build_id_bfd_get (abfd); |
| 611 | |
| 612 | if (found == NULL) |
| 613 | warning (_("File \"%s\" has no build-id, file skipped"), filename); |
| 614 | else if (found->size != check->size |
| 615 | || memcmp (found->data, check->data, found->size) != 0) |
| 616 | warning (_("File \"%s\" has a different build-id, file skipped"), filename); |
| 617 | else |
| 618 | retval = 1; |
| 619 | |
| 620 | if (!bfd_close (abfd)) |
| 621 | warning (_("cannot close \"%s\": %s"), filename, |
| 622 | bfd_errmsg (bfd_get_error ())); |
| 623 | |
| 624 | xfree (found); |
| 625 | |
| 626 | return retval; |
| 627 | } |
| 628 | |
| 629 | static char * |
| 630 | build_id_to_debug_filename (struct build_id *build_id) |
| 631 | { |
| 632 | char *link, *debugdir, *retval = NULL; |
| 633 | |
| 634 | /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */ |
| 635 | link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1 |
| 636 | + 2 * build_id->size + (sizeof ".debug" - 1) + 1); |
| 637 | |
| 638 | /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will |
| 639 | cause "/.build-id/..." lookups. */ |
| 640 | |
| 641 | debugdir = debug_file_directory; |
| 642 | do |
| 643 | { |
| 644 | char *s, *debugdir_end; |
| 645 | gdb_byte *data = build_id->data; |
| 646 | size_t size = build_id->size; |
| 647 | |
| 648 | while (*debugdir == DIRNAME_SEPARATOR) |
| 649 | debugdir++; |
| 650 | |
| 651 | debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR); |
| 652 | if (debugdir_end == NULL) |
| 653 | debugdir_end = &debugdir[strlen (debugdir)]; |
| 654 | |
| 655 | memcpy (link, debugdir, debugdir_end - debugdir); |
| 656 | s = &link[debugdir_end - debugdir]; |
| 657 | s += sprintf (s, "/.build-id/"); |
| 658 | if (size > 0) |
| 659 | { |
| 660 | size--; |
| 661 | s += sprintf (s, "%02x", (unsigned) *data++); |
| 662 | } |
| 663 | if (size > 0) |
| 664 | *s++ = '/'; |
| 665 | while (size-- > 0) |
| 666 | s += sprintf (s, "%02x", (unsigned) *data++); |
| 667 | strcpy (s, ".debug"); |
| 668 | |
| 669 | /* lrealpath() is expensive even for the usually non-existent files. */ |
| 670 | if (access (link, F_OK) == 0) |
| 671 | retval = lrealpath (link); |
| 672 | |
| 673 | if (retval != NULL && !build_id_verify (retval, build_id)) |
| 674 | { |
| 675 | xfree (retval); |
| 676 | retval = NULL; |
| 677 | } |
| 678 | |
| 679 | if (retval != NULL) |
| 680 | break; |
| 681 | |
| 682 | debugdir = debugdir_end; |
| 683 | } |
| 684 | while (*debugdir != 0); |
| 685 | |
| 686 | return retval; |
| 687 | } |
| 688 | |
| 689 | static char * |
| 690 | find_separate_debug_file_by_buildid (struct objfile *objfile) |
| 691 | { |
| 692 | asection *sect; |
| 693 | char *basename, *name_copy, *debugdir; |
| 694 | char *dir = NULL; |
| 695 | char *debugfile = NULL; |
| 696 | char *canon_name = NULL; |
| 697 | bfd_size_type debuglink_size; |
| 698 | unsigned long crc32; |
| 699 | int i; |
| 700 | struct build_id *build_id; |
| 701 | |
| 702 | build_id = build_id_bfd_get (objfile->obfd); |
| 703 | if (build_id != NULL) |
| 704 | { |
| 705 | char *build_id_name; |
| 706 | |
| 707 | build_id_name = build_id_to_debug_filename (build_id); |
| 708 | xfree (build_id); |
| 709 | /* Prevent looping on a stripped .debug file. */ |
| 710 | if (build_id_name != NULL && strcmp (build_id_name, objfile->name) == 0) |
| 711 | { |
| 712 | warning (_("\"%s\": separate debug info file has no debug info"), |
| 713 | build_id_name); |
| 714 | xfree (build_id_name); |
| 715 | } |
| 716 | else if (build_id_name != NULL) |
| 717 | return build_id_name; |
| 718 | } |
| 719 | return NULL; |
| 720 | } |
| 721 | |
| 722 | /* Scan and build partial symbols for a symbol file. |
| 723 | We have been initialized by a call to elf_symfile_init, which |
| 724 | currently does nothing. |
| 725 | |
| 726 | SECTION_OFFSETS is a set of offsets to apply to relocate the symbols |
| 727 | in each section. We simplify it down to a single offset for all |
| 728 | symbols. FIXME. |
| 729 | |
| 730 | This function only does the minimum work necessary for letting the |
| 731 | user "name" things symbolically; it does not read the entire symtab. |
| 732 | Instead, it reads the external and static symbols and puts them in partial |
| 733 | symbol tables. When more extensive information is requested of a |
| 734 | file, the corresponding partial symbol table is mutated into a full |
| 735 | fledged symbol table by going back and reading the symbols |
| 736 | for real. |
| 737 | |
| 738 | We look for sections with specific names, to tell us what debug |
| 739 | format to look for: FIXME!!! |
| 740 | |
| 741 | elfstab_build_psymtabs() handles STABS symbols; |
| 742 | mdebug_build_psymtabs() handles ECOFF debugging information. |
| 743 | |
| 744 | Note that ELF files have a "minimal" symbol table, which looks a lot |
| 745 | like a COFF symbol table, but has only the minimal information necessary |
| 746 | for linking. We process this also, and use the information to |
| 747 | build gdb's minimal symbol table. This gives us some minimal debugging |
| 748 | capability even for files compiled without -g. */ |
| 749 | |
| 750 | static void |
| 751 | elf_symfile_read (struct objfile *objfile, int symfile_flags) |
| 752 | { |
| 753 | bfd *abfd = objfile->obfd; |
| 754 | struct elfinfo ei; |
| 755 | struct cleanup *back_to; |
| 756 | CORE_ADDR offset; |
| 757 | long symcount = 0, dynsymcount = 0, synthcount, storage_needed; |
| 758 | asymbol **symbol_table = NULL, **dyn_symbol_table = NULL; |
| 759 | asymbol *synthsyms; |
| 760 | |
| 761 | init_minimal_symbol_collection (); |
| 762 | back_to = make_cleanup_discard_minimal_symbols (); |
| 763 | |
| 764 | memset ((char *) &ei, 0, sizeof (ei)); |
| 765 | |
| 766 | /* Allocate struct to keep track of the symfile */ |
| 767 | objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *) |
| 768 | xmalloc (sizeof (struct dbx_symfile_info)); |
| 769 | memset ((char *) objfile->deprecated_sym_stab_info, 0, sizeof (struct dbx_symfile_info)); |
| 770 | make_cleanup (free_elfinfo, (void *) objfile); |
| 771 | |
| 772 | /* Process the normal ELF symbol table first. This may write some |
| 773 | chain of info into the dbx_symfile_info in objfile->deprecated_sym_stab_info, |
| 774 | which can later be used by elfstab_offset_sections. */ |
| 775 | |
| 776 | storage_needed = bfd_get_symtab_upper_bound (objfile->obfd); |
| 777 | if (storage_needed < 0) |
| 778 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), |
| 779 | bfd_errmsg (bfd_get_error ())); |
| 780 | |
| 781 | if (storage_needed > 0) |
| 782 | { |
| 783 | symbol_table = (asymbol **) xmalloc (storage_needed); |
| 784 | make_cleanup (xfree, symbol_table); |
| 785 | symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table); |
| 786 | |
| 787 | if (symcount < 0) |
| 788 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), |
| 789 | bfd_errmsg (bfd_get_error ())); |
| 790 | |
| 791 | elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0); |
| 792 | } |
| 793 | |
| 794 | /* Add the dynamic symbols. */ |
| 795 | |
| 796 | storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd); |
| 797 | |
| 798 | if (storage_needed > 0) |
| 799 | { |
| 800 | dyn_symbol_table = (asymbol **) xmalloc (storage_needed); |
| 801 | make_cleanup (xfree, dyn_symbol_table); |
| 802 | dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd, |
| 803 | dyn_symbol_table); |
| 804 | |
| 805 | if (dynsymcount < 0) |
| 806 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), |
| 807 | bfd_errmsg (bfd_get_error ())); |
| 808 | |
| 809 | elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0); |
| 810 | } |
| 811 | |
| 812 | /* Add synthetic symbols - for instance, names for any PLT entries. */ |
| 813 | |
| 814 | synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table, |
| 815 | dynsymcount, dyn_symbol_table, |
| 816 | &synthsyms); |
| 817 | if (synthcount > 0) |
| 818 | { |
| 819 | asymbol **synth_symbol_table; |
| 820 | long i; |
| 821 | |
| 822 | make_cleanup (xfree, synthsyms); |
| 823 | synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount); |
| 824 | for (i = 0; i < synthcount; i++) |
| 825 | synth_symbol_table[i] = synthsyms + i; |
| 826 | make_cleanup (xfree, synth_symbol_table); |
| 827 | elf_symtab_read (objfile, ST_SYNTHETIC, synthcount, synth_symbol_table, 1); |
| 828 | } |
| 829 | |
| 830 | /* Install any minimal symbols that have been collected as the current |
| 831 | minimal symbols for this objfile. The debug readers below this point |
| 832 | should not generate new minimal symbols; if they do it's their |
| 833 | responsibility to install them. "mdebug" appears to be the only one |
| 834 | which will do this. */ |
| 835 | |
| 836 | install_minimal_symbols (objfile); |
| 837 | do_cleanups (back_to); |
| 838 | |
| 839 | /* Now process debugging information, which is contained in |
| 840 | special ELF sections. */ |
| 841 | |
| 842 | /* We first have to find them... */ |
| 843 | bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei); |
| 844 | |
| 845 | /* ELF debugging information is inserted into the psymtab in the |
| 846 | order of least informative first - most informative last. Since |
| 847 | the psymtab table is searched `most recent insertion first' this |
| 848 | increases the probability that more detailed debug information |
| 849 | for a section is found. |
| 850 | |
| 851 | For instance, an object file might contain both .mdebug (XCOFF) |
| 852 | and .debug_info (DWARF2) sections then .mdebug is inserted first |
| 853 | (searched last) and DWARF2 is inserted last (searched first). If |
| 854 | we don't do this then the XCOFF info is found first - for code in |
| 855 | an included file XCOFF info is useless. */ |
| 856 | |
| 857 | if (ei.mdebugsect) |
| 858 | { |
| 859 | const struct ecoff_debug_swap *swap; |
| 860 | |
| 861 | /* .mdebug section, presumably holding ECOFF debugging |
| 862 | information. */ |
| 863 | swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; |
| 864 | if (swap) |
| 865 | elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect); |
| 866 | } |
| 867 | if (ei.stabsect) |
| 868 | { |
| 869 | asection *str_sect; |
| 870 | |
| 871 | /* Stab sections have an associated string table that looks like |
| 872 | a separate section. */ |
| 873 | str_sect = bfd_get_section_by_name (abfd, ".stabstr"); |
| 874 | |
| 875 | /* FIXME should probably warn about a stab section without a stabstr. */ |
| 876 | if (str_sect) |
| 877 | elfstab_build_psymtabs (objfile, |
| 878 | ei.stabsect, |
| 879 | str_sect->filepos, |
| 880 | bfd_section_size (abfd, str_sect)); |
| 881 | } |
| 882 | if (dwarf2_has_info (objfile)) |
| 883 | { |
| 884 | /* DWARF 2 sections */ |
| 885 | dwarf2_build_psymtabs (objfile); |
| 886 | } |
| 887 | |
| 888 | /* FIXME: kettenis/20030504: This still needs to be integrated with |
| 889 | dwarf2read.c in a better way. */ |
| 890 | dwarf2_build_frame_info (objfile); |
| 891 | |
| 892 | /* If the file has its own symbol tables it has no separate debug info. |
| 893 | `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to SYMTABS/PSYMTABS. |
| 894 | `.gnu_debuglink' may no longer be present with `.note.gnu.build-id'. */ |
| 895 | if (!objfile_has_partial_symbols (objfile)) |
| 896 | { |
| 897 | char *debugfile; |
| 898 | |
| 899 | debugfile = find_separate_debug_file_by_buildid (objfile); |
| 900 | |
| 901 | if (debugfile == NULL) |
| 902 | debugfile = find_separate_debug_file_by_debuglink (objfile); |
| 903 | |
| 904 | if (debugfile) |
| 905 | { |
| 906 | bfd *abfd = symfile_bfd_open (debugfile); |
| 907 | symbol_file_add_separate (abfd, symfile_flags, objfile); |
| 908 | xfree (debugfile); |
| 909 | } |
| 910 | } |
| 911 | } |
| 912 | |
| 913 | /* This cleans up the objfile's deprecated_sym_stab_info pointer, and |
| 914 | the chain of stab_section_info's, that might be dangling from |
| 915 | it. */ |
| 916 | |
| 917 | static void |
| 918 | free_elfinfo (void *objp) |
| 919 | { |
| 920 | struct objfile *objfile = (struct objfile *) objp; |
| 921 | struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info; |
| 922 | struct stab_section_info *ssi, *nssi; |
| 923 | |
| 924 | ssi = dbxinfo->stab_section_info; |
| 925 | while (ssi) |
| 926 | { |
| 927 | nssi = ssi->next; |
| 928 | xfree (ssi); |
| 929 | ssi = nssi; |
| 930 | } |
| 931 | |
| 932 | dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ |
| 933 | } |
| 934 | |
| 935 | |
| 936 | /* Initialize anything that needs initializing when a completely new symbol |
| 937 | file is specified (not just adding some symbols from another file, e.g. a |
| 938 | shared library). |
| 939 | |
| 940 | We reinitialize buildsym, since we may be reading stabs from an ELF file. */ |
| 941 | |
| 942 | static void |
| 943 | elf_new_init (struct objfile *ignore) |
| 944 | { |
| 945 | stabsread_new_init (); |
| 946 | buildsym_new_init (); |
| 947 | } |
| 948 | |
| 949 | /* Perform any local cleanups required when we are done with a particular |
| 950 | objfile. I.E, we are in the process of discarding all symbol information |
| 951 | for an objfile, freeing up all memory held for it, and unlinking the |
| 952 | objfile struct from the global list of known objfiles. */ |
| 953 | |
| 954 | static void |
| 955 | elf_symfile_finish (struct objfile *objfile) |
| 956 | { |
| 957 | if (objfile->deprecated_sym_stab_info != NULL) |
| 958 | { |
| 959 | xfree (objfile->deprecated_sym_stab_info); |
| 960 | } |
| 961 | |
| 962 | dwarf2_free_objfile (objfile); |
| 963 | } |
| 964 | |
| 965 | /* ELF specific initialization routine for reading symbols. |
| 966 | |
| 967 | It is passed a pointer to a struct sym_fns which contains, among other |
| 968 | things, the BFD for the file whose symbols are being read, and a slot for |
| 969 | a pointer to "private data" which we can fill with goodies. |
| 970 | |
| 971 | For now at least, we have nothing in particular to do, so this function is |
| 972 | just a stub. */ |
| 973 | |
| 974 | static void |
| 975 | elf_symfile_init (struct objfile *objfile) |
| 976 | { |
| 977 | /* ELF objects may be reordered, so set OBJF_REORDERED. If we |
| 978 | find this causes a significant slowdown in gdb then we could |
| 979 | set it in the debug symbol readers only when necessary. */ |
| 980 | objfile->flags |= OBJF_REORDERED; |
| 981 | } |
| 982 | |
| 983 | /* When handling an ELF file that contains Sun STABS debug info, |
| 984 | some of the debug info is relative to the particular chunk of the |
| 985 | section that was generated in its individual .o file. E.g. |
| 986 | offsets to static variables are relative to the start of the data |
| 987 | segment *for that module before linking*. This information is |
| 988 | painfully squirreled away in the ELF symbol table as local symbols |
| 989 | with wierd names. Go get 'em when needed. */ |
| 990 | |
| 991 | void |
| 992 | elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst) |
| 993 | { |
| 994 | char *filename = pst->filename; |
| 995 | struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; |
| 996 | struct stab_section_info *maybe = dbx->stab_section_info; |
| 997 | struct stab_section_info *questionable = 0; |
| 998 | int i; |
| 999 | char *p; |
| 1000 | |
| 1001 | /* The ELF symbol info doesn't include path names, so strip the path |
| 1002 | (if any) from the psymtab filename. */ |
| 1003 | while (0 != (p = strchr (filename, '/'))) |
| 1004 | filename = p + 1; |
| 1005 | |
| 1006 | /* FIXME: This linear search could speed up significantly |
| 1007 | if it was chained in the right order to match how we search it, |
| 1008 | and if we unchained when we found a match. */ |
| 1009 | for (; maybe; maybe = maybe->next) |
| 1010 | { |
| 1011 | if (filename[0] == maybe->filename[0] |
| 1012 | && strcmp (filename, maybe->filename) == 0) |
| 1013 | { |
| 1014 | /* We found a match. But there might be several source files |
| 1015 | (from different directories) with the same name. */ |
| 1016 | if (0 == maybe->found) |
| 1017 | break; |
| 1018 | questionable = maybe; /* Might use it later. */ |
| 1019 | } |
| 1020 | } |
| 1021 | |
| 1022 | if (maybe == 0 && questionable != 0) |
| 1023 | { |
| 1024 | complaint (&symfile_complaints, |
| 1025 | _("elf/stab section information questionable for %s"), filename); |
| 1026 | maybe = questionable; |
| 1027 | } |
| 1028 | |
| 1029 | if (maybe) |
| 1030 | { |
| 1031 | /* Found it! Allocate a new psymtab struct, and fill it in. */ |
| 1032 | maybe->found++; |
| 1033 | pst->section_offsets = (struct section_offsets *) |
| 1034 | obstack_alloc (&objfile->objfile_obstack, |
| 1035 | SIZEOF_N_SECTION_OFFSETS (objfile->num_sections)); |
| 1036 | for (i = 0; i < maybe->num_sections; i++) |
| 1037 | (pst->section_offsets)->offsets[i] = maybe->sections[i]; |
| 1038 | return; |
| 1039 | } |
| 1040 | |
| 1041 | /* We were unable to find any offsets for this file. Complain. */ |
| 1042 | if (dbx->stab_section_info) /* If there *is* any info, */ |
| 1043 | complaint (&symfile_complaints, |
| 1044 | _("elf/stab section information missing for %s"), filename); |
| 1045 | } |
| 1046 | \f |
| 1047 | /* Register that we are able to handle ELF object file formats. */ |
| 1048 | |
| 1049 | static struct sym_fns elf_sym_fns = |
| 1050 | { |
| 1051 | bfd_target_elf_flavour, |
| 1052 | elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ |
| 1053 | elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ |
| 1054 | elf_symfile_read, /* sym_read: read a symbol file into symtab */ |
| 1055 | elf_symfile_finish, /* sym_finish: finished with file, cleanup */ |
| 1056 | default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */ |
| 1057 | elf_symfile_segments, /* sym_segments: Get segment information from |
| 1058 | a file. */ |
| 1059 | NULL, /* sym_read_linetable */ |
| 1060 | NULL /* next: pointer to next struct sym_fns */ |
| 1061 | }; |
| 1062 | |
| 1063 | void |
| 1064 | _initialize_elfread (void) |
| 1065 | { |
| 1066 | add_symtab_fns (&elf_sym_fns); |
| 1067 | } |