| 1 | /* Read ELF (Executable and Linking Format) object files for GDB. |
| 2 | Copyright 1991, 92, 93, 94, 95, 96, 1998 Free Software Foundation, Inc. |
| 3 | Written by Fred Fish at Cygnus Support. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 2 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program; if not, write to the Free Software |
| 19 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 20 | Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "bfd.h" |
| 24 | #include "gdb_string.h" |
| 25 | #include "elf-bfd.h" |
| 26 | #include "elf/mips.h" |
| 27 | #include "symtab.h" |
| 28 | #include "symfile.h" |
| 29 | #include "objfiles.h" |
| 30 | #include "buildsym.h" |
| 31 | #include "stabsread.h" |
| 32 | #include "gdb-stabs.h" |
| 33 | #include "complaints.h" |
| 34 | #include "demangle.h" |
| 35 | |
| 36 | extern void _initialize_elfread (void); |
| 37 | |
| 38 | /* The struct elfinfo is available only during ELF symbol table and |
| 39 | psymtab reading. It is destroyed at the completion of psymtab-reading. |
| 40 | It's local to elf_symfile_read. */ |
| 41 | |
| 42 | struct elfinfo |
| 43 | { |
| 44 | file_ptr dboffset; /* Offset to dwarf debug section */ |
| 45 | unsigned int dbsize; /* Size of dwarf debug section */ |
| 46 | file_ptr lnoffset; /* Offset to dwarf line number section */ |
| 47 | unsigned int lnsize; /* Size of dwarf line number section */ |
| 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 | /* Various things we might complain about... */ |
| 54 | |
| 55 | struct complaint section_info_complaint = |
| 56 | {"elf/stab section information %s without a preceding file symbol", 0, 0}; |
| 57 | |
| 58 | struct complaint section_info_dup_complaint = |
| 59 | {"duplicated elf/stab section information for %s", 0, 0}; |
| 60 | |
| 61 | struct complaint stab_info_mismatch_complaint = |
| 62 | {"elf/stab section information missing for %s", 0, 0}; |
| 63 | |
| 64 | struct complaint stab_info_questionable_complaint = |
| 65 | {"elf/stab section information questionable for %s", 0, 0}; |
| 66 | |
| 67 | static void elf_symfile_init (struct objfile *); |
| 68 | |
| 69 | static void elf_new_init (struct objfile *); |
| 70 | |
| 71 | static void elf_symfile_read (struct objfile *, int); |
| 72 | |
| 73 | static void elf_symfile_finish (struct objfile *); |
| 74 | |
| 75 | static void elf_symtab_read (struct objfile *, int); |
| 76 | |
| 77 | static void free_elfinfo (void *); |
| 78 | |
| 79 | static struct minimal_symbol *record_minimal_symbol_and_info (char *, |
| 80 | CORE_ADDR, |
| 81 | enum |
| 82 | minimal_symbol_type, |
| 83 | char *, |
| 84 | asection * |
| 85 | bfd_section, |
| 86 | struct objfile |
| 87 | *); |
| 88 | |
| 89 | static void elf_locate_sections (bfd *, asection *, void *); |
| 90 | |
| 91 | /* We are called once per section from elf_symfile_read. We |
| 92 | need to examine each section we are passed, check to see |
| 93 | if it is something we are interested in processing, and |
| 94 | if so, stash away some access information for the section. |
| 95 | |
| 96 | For now we recognize the dwarf debug information sections and |
| 97 | line number sections from matching their section names. The |
| 98 | ELF definition is no real help here since it has no direct |
| 99 | knowledge of DWARF (by design, so any debugging format can be |
| 100 | used). |
| 101 | |
| 102 | We also recognize the ".stab" sections used by the Sun compilers |
| 103 | released with Solaris 2. |
| 104 | |
| 105 | FIXME: The section names should not be hardwired strings (what |
| 106 | should they be? I don't think most object file formats have enough |
| 107 | section flags to specify what kind of debug section it is |
| 108 | -kingdon). */ |
| 109 | |
| 110 | static void |
| 111 | elf_locate_sections (bfd *ignore_abfd, asection *sectp, PTR eip) |
| 112 | { |
| 113 | register struct elfinfo *ei; |
| 114 | |
| 115 | ei = (struct elfinfo *) eip; |
| 116 | if (STREQ (sectp->name, ".debug")) |
| 117 | { |
| 118 | ei->dboffset = sectp->filepos; |
| 119 | ei->dbsize = bfd_get_section_size_before_reloc (sectp); |
| 120 | } |
| 121 | else if (STREQ (sectp->name, ".line")) |
| 122 | { |
| 123 | ei->lnoffset = sectp->filepos; |
| 124 | ei->lnsize = bfd_get_section_size_before_reloc (sectp); |
| 125 | } |
| 126 | else if (STREQ (sectp->name, ".stab")) |
| 127 | { |
| 128 | ei->stabsect = sectp; |
| 129 | } |
| 130 | else if (STREQ (sectp->name, ".stab.index")) |
| 131 | { |
| 132 | ei->stabindexsect = sectp; |
| 133 | } |
| 134 | else if (STREQ (sectp->name, ".mdebug")) |
| 135 | { |
| 136 | ei->mdebugsect = sectp; |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | #if 0 /* Currently unused */ |
| 141 | |
| 142 | char * |
| 143 | elf_interpreter (bfd *abfd) |
| 144 | { |
| 145 | sec_ptr interp_sec; |
| 146 | unsigned size; |
| 147 | char *interp = NULL; |
| 148 | |
| 149 | interp_sec = bfd_get_section_by_name (abfd, ".interp"); |
| 150 | if (interp_sec) |
| 151 | { |
| 152 | size = bfd_section_size (abfd, interp_sec); |
| 153 | interp = alloca (size); |
| 154 | if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr) 0, |
| 155 | size)) |
| 156 | { |
| 157 | interp = savestring (interp, size - 1); |
| 158 | } |
| 159 | else |
| 160 | { |
| 161 | interp = NULL; |
| 162 | } |
| 163 | } |
| 164 | return (interp); |
| 165 | } |
| 166 | |
| 167 | #endif |
| 168 | |
| 169 | static struct minimal_symbol * |
| 170 | record_minimal_symbol_and_info (char *name, CORE_ADDR address, |
| 171 | enum minimal_symbol_type ms_type, char *info, /* FIXME, is this really char *? */ |
| 172 | asection *bfd_section, struct objfile *objfile) |
| 173 | { |
| 174 | int section; |
| 175 | |
| 176 | /* Guess the section from the type. This is likely to be wrong in |
| 177 | some cases. */ |
| 178 | switch (ms_type) |
| 179 | { |
| 180 | case mst_text: |
| 181 | case mst_file_text: |
| 182 | section = bfd_section->index; |
| 183 | #ifdef SMASH_TEXT_ADDRESS |
| 184 | SMASH_TEXT_ADDRESS (address); |
| 185 | #endif |
| 186 | break; |
| 187 | case mst_data: |
| 188 | case mst_file_data: |
| 189 | case mst_bss: |
| 190 | case mst_file_bss: |
| 191 | section = bfd_section->index; |
| 192 | break; |
| 193 | default: |
| 194 | section = -1; |
| 195 | break; |
| 196 | } |
| 197 | |
| 198 | return prim_record_minimal_symbol_and_info |
| 199 | (name, address, ms_type, info, section, bfd_section, objfile); |
| 200 | } |
| 201 | |
| 202 | /* |
| 203 | |
| 204 | LOCAL FUNCTION |
| 205 | |
| 206 | elf_symtab_read -- read the symbol table of an ELF file |
| 207 | |
| 208 | SYNOPSIS |
| 209 | |
| 210 | void elf_symtab_read (struct objfile *objfile, int dynamic) |
| 211 | |
| 212 | DESCRIPTION |
| 213 | |
| 214 | Given an objfile and a flag that specifies whether or not the objfile |
| 215 | is for an executable or not (may be shared library for example), add |
| 216 | all the global function and data symbols to the minimal symbol table. |
| 217 | |
| 218 | In stabs-in-ELF, as implemented by Sun, there are some local symbols |
| 219 | defined in the ELF symbol table, which can be used to locate |
| 220 | the beginnings of sections from each ".o" file that was linked to |
| 221 | form the executable objfile. We gather any such info and record it |
| 222 | in data structures hung off the objfile's private data. |
| 223 | |
| 224 | */ |
| 225 | |
| 226 | static void |
| 227 | elf_symtab_read (struct objfile *objfile, int dynamic) |
| 228 | { |
| 229 | long storage_needed; |
| 230 | asymbol *sym; |
| 231 | asymbol **symbol_table; |
| 232 | long number_of_symbols; |
| 233 | long i; |
| 234 | int index; |
| 235 | struct cleanup *back_to; |
| 236 | CORE_ADDR symaddr; |
| 237 | CORE_ADDR offset; |
| 238 | enum minimal_symbol_type ms_type; |
| 239 | /* If sectinfo is nonNULL, it contains section info that should end up |
| 240 | filed in the objfile. */ |
| 241 | struct stab_section_info *sectinfo = NULL; |
| 242 | /* If filesym is nonzero, it points to a file symbol, but we haven't |
| 243 | seen any section info for it yet. */ |
| 244 | asymbol *filesym = 0; |
| 245 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 246 | /* Name of filesym, as saved on the symbol_obstack. */ |
| 247 | char *filesymname = obsavestring ("", 0, &objfile->symbol_obstack); |
| 248 | #endif |
| 249 | struct dbx_symfile_info *dbx = objfile->sym_stab_info; |
| 250 | unsigned long size; |
| 251 | int stripped = (bfd_get_symcount (objfile->obfd) == 0); |
| 252 | |
| 253 | if (dynamic) |
| 254 | { |
| 255 | storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd); |
| 256 | |
| 257 | /* Nothing to be done if there is no dynamic symtab. */ |
| 258 | if (storage_needed < 0) |
| 259 | return; |
| 260 | } |
| 261 | else |
| 262 | { |
| 263 | storage_needed = bfd_get_symtab_upper_bound (objfile->obfd); |
| 264 | if (storage_needed < 0) |
| 265 | error ("Can't read symbols from %s: %s", bfd_get_filename (objfile->obfd), |
| 266 | bfd_errmsg (bfd_get_error ())); |
| 267 | } |
| 268 | if (storage_needed > 0) |
| 269 | { |
| 270 | symbol_table = (asymbol **) xmalloc (storage_needed); |
| 271 | back_to = make_cleanup (free, symbol_table); |
| 272 | if (dynamic) |
| 273 | number_of_symbols = bfd_canonicalize_dynamic_symtab (objfile->obfd, |
| 274 | symbol_table); |
| 275 | else |
| 276 | number_of_symbols = bfd_canonicalize_symtab (objfile->obfd, symbol_table); |
| 277 | if (number_of_symbols < 0) |
| 278 | error ("Can't read symbols from %s: %s", bfd_get_filename (objfile->obfd), |
| 279 | bfd_errmsg (bfd_get_error ())); |
| 280 | |
| 281 | for (i = 0; i < number_of_symbols; i++) |
| 282 | { |
| 283 | sym = symbol_table[i]; |
| 284 | if (sym->name == NULL || *sym->name == '\0') |
| 285 | { |
| 286 | /* Skip names that don't exist (shouldn't happen), or names |
| 287 | that are null strings (may happen). */ |
| 288 | continue; |
| 289 | } |
| 290 | |
| 291 | offset = ANOFFSET (objfile->section_offsets, sym->section->index); |
| 292 | if (dynamic |
| 293 | && sym->section == &bfd_und_section |
| 294 | && (sym->flags & BSF_FUNCTION)) |
| 295 | { |
| 296 | struct minimal_symbol *msym; |
| 297 | |
| 298 | /* Symbol is a reference to a function defined in |
| 299 | a shared library. |
| 300 | If its value is non zero then it is usually the address |
| 301 | of the corresponding entry in the procedure linkage table, |
| 302 | plus the desired section offset. |
| 303 | If its value is zero then the dynamic linker has to resolve |
| 304 | the symbol. We are unable to find any meaningful address |
| 305 | for this symbol in the executable file, so we skip it. */ |
| 306 | symaddr = sym->value; |
| 307 | if (symaddr == 0) |
| 308 | continue; |
| 309 | symaddr += offset; |
| 310 | msym = record_minimal_symbol_and_info |
| 311 | ((char *) sym->name, symaddr, |
| 312 | mst_solib_trampoline, NULL, sym->section, objfile); |
| 313 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 314 | if (msym != NULL) |
| 315 | msym->filename = filesymname; |
| 316 | #endif |
| 317 | continue; |
| 318 | } |
| 319 | |
| 320 | /* If it is a nonstripped executable, do not enter dynamic |
| 321 | symbols, as the dynamic symbol table is usually a subset |
| 322 | of the main symbol table. */ |
| 323 | if (dynamic && !stripped) |
| 324 | continue; |
| 325 | if (sym->flags & BSF_FILE) |
| 326 | { |
| 327 | /* STT_FILE debugging symbol that helps stabs-in-elf debugging. |
| 328 | Chain any old one onto the objfile; remember new sym. */ |
| 329 | if (sectinfo != NULL) |
| 330 | { |
| 331 | sectinfo->next = dbx->stab_section_info; |
| 332 | dbx->stab_section_info = sectinfo; |
| 333 | sectinfo = NULL; |
| 334 | } |
| 335 | filesym = sym; |
| 336 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 337 | filesymname = |
| 338 | obsavestring ((char *) filesym->name, strlen (filesym->name), |
| 339 | &objfile->symbol_obstack); |
| 340 | #endif |
| 341 | } |
| 342 | else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) |
| 343 | { |
| 344 | struct minimal_symbol *msym; |
| 345 | |
| 346 | /* Select global/local/weak symbols. Note that bfd puts abs |
| 347 | symbols in their own section, so all symbols we are |
| 348 | interested in will have a section. */ |
| 349 | /* Bfd symbols are section relative. */ |
| 350 | symaddr = sym->value + sym->section->vma; |
| 351 | /* Relocate all non-absolute symbols by the section offset. */ |
| 352 | if (sym->section != &bfd_abs_section) |
| 353 | { |
| 354 | symaddr += offset; |
| 355 | } |
| 356 | /* For non-absolute symbols, use the type of the section |
| 357 | they are relative to, to intuit text/data. Bfd provides |
| 358 | no way of figuring this out for absolute symbols. */ |
| 359 | if (sym->section == &bfd_abs_section) |
| 360 | { |
| 361 | /* This is a hack to get the minimal symbol type |
| 362 | right for Irix 5, which has absolute addresses |
| 363 | with special section indices for dynamic symbols. */ |
| 364 | unsigned short shndx = |
| 365 | ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; |
| 366 | |
| 367 | switch (shndx) |
| 368 | { |
| 369 | case SHN_MIPS_TEXT: |
| 370 | ms_type = mst_text; |
| 371 | break; |
| 372 | case SHN_MIPS_DATA: |
| 373 | ms_type = mst_data; |
| 374 | break; |
| 375 | case SHN_MIPS_ACOMMON: |
| 376 | ms_type = mst_bss; |
| 377 | break; |
| 378 | default: |
| 379 | ms_type = mst_abs; |
| 380 | } |
| 381 | |
| 382 | /* If it is an Irix dynamic symbol, skip section name |
| 383 | symbols, relocate all others by section offset. */ |
| 384 | if (ms_type != mst_abs) |
| 385 | { |
| 386 | if (sym->name[0] == '.') |
| 387 | continue; |
| 388 | symaddr += offset; |
| 389 | } |
| 390 | } |
| 391 | else if (sym->section->flags & SEC_CODE) |
| 392 | { |
| 393 | if (sym->flags & BSF_GLOBAL) |
| 394 | { |
| 395 | ms_type = mst_text; |
| 396 | } |
| 397 | else if ((sym->name[0] == '.' && sym->name[1] == 'L') |
| 398 | || ((sym->flags & BSF_LOCAL) |
| 399 | && sym->name[0] == '$' |
| 400 | && sym->name[1] == 'L')) |
| 401 | /* Looks like a compiler-generated label. Skip it. |
| 402 | The assembler should be skipping these (to keep |
| 403 | executables small), but apparently with gcc on the |
| 404 | delta m88k SVR4, it loses. So to have us check too |
| 405 | should be harmless (but I encourage people to fix this |
| 406 | in the assembler instead of adding checks here). */ |
| 407 | continue; |
| 408 | #ifdef HARRIS_TARGET |
| 409 | else if (sym->name[0] == '.' && sym->name[1] == '.') |
| 410 | { |
| 411 | /* Looks like a Harris compiler generated label for the |
| 412 | purpose of marking instructions that are relevant to |
| 413 | DWARF dies. The assembler can't get rid of these |
| 414 | because they are relocatable addresses that the |
| 415 | linker needs to resolve. */ |
| 416 | continue; |
| 417 | } |
| 418 | #endif |
| 419 | else |
| 420 | { |
| 421 | ms_type = mst_file_text; |
| 422 | } |
| 423 | } |
| 424 | else if (sym->section->flags & SEC_ALLOC) |
| 425 | { |
| 426 | if (sym->flags & BSF_GLOBAL) |
| 427 | { |
| 428 | if (sym->section->flags & SEC_LOAD) |
| 429 | { |
| 430 | ms_type = mst_data; |
| 431 | } |
| 432 | else |
| 433 | { |
| 434 | ms_type = mst_bss; |
| 435 | } |
| 436 | } |
| 437 | else if (sym->flags & BSF_LOCAL) |
| 438 | { |
| 439 | /* Named Local variable in a Data section. Check its |
| 440 | name for stabs-in-elf. The STREQ macro checks the |
| 441 | first character inline, so we only actually do a |
| 442 | strcmp function call on names that start with 'B' |
| 443 | or 'D' */ |
| 444 | index = SECT_OFF_MAX; |
| 445 | if (STREQ ("Bbss.bss", sym->name)) |
| 446 | { |
| 447 | index = SECT_OFF_BSS (objfile); |
| 448 | } |
| 449 | else if (STREQ ("Ddata.data", sym->name)) |
| 450 | { |
| 451 | index = SECT_OFF_DATA (objfile); |
| 452 | } |
| 453 | else if (STREQ ("Drodata.rodata", sym->name)) |
| 454 | { |
| 455 | index = SECT_OFF_RODATA (objfile); |
| 456 | } |
| 457 | if (index != SECT_OFF_MAX) |
| 458 | { |
| 459 | /* Found a special local symbol. Allocate a |
| 460 | sectinfo, if needed, and fill it in. */ |
| 461 | if (sectinfo == NULL) |
| 462 | { |
| 463 | sectinfo = (struct stab_section_info *) |
| 464 | xmmalloc (objfile->md, sizeof (*sectinfo)); |
| 465 | memset ((PTR) sectinfo, 0, sizeof (*sectinfo)); |
| 466 | if (filesym == NULL) |
| 467 | { |
| 468 | complain (§ion_info_complaint, |
| 469 | sym->name); |
| 470 | } |
| 471 | else |
| 472 | { |
| 473 | sectinfo->filename = |
| 474 | (char *) filesym->name; |
| 475 | } |
| 476 | } |
| 477 | if (index != -1) |
| 478 | { |
| 479 | if (sectinfo->sections[index] != 0) |
| 480 | { |
| 481 | complain (§ion_info_dup_complaint, |
| 482 | sectinfo->filename); |
| 483 | } |
| 484 | } |
| 485 | else |
| 486 | internal_error ("Section index uninitialized."); |
| 487 | /* Bfd symbols are section relative. */ |
| 488 | symaddr = sym->value + sym->section->vma; |
| 489 | /* Relocate non-absolute symbols by the section offset. */ |
| 490 | if (sym->section != &bfd_abs_section) |
| 491 | { |
| 492 | symaddr += offset; |
| 493 | } |
| 494 | if (index != -1) |
| 495 | sectinfo->sections[index] = symaddr; |
| 496 | else |
| 497 | internal_error ("Section index uninitialized."); |
| 498 | /* The special local symbols don't go in the |
| 499 | minimal symbol table, so ignore this one. */ |
| 500 | continue; |
| 501 | } |
| 502 | /* Not a special stabs-in-elf symbol, do regular |
| 503 | symbol processing. */ |
| 504 | if (sym->section->flags & SEC_LOAD) |
| 505 | { |
| 506 | ms_type = mst_file_data; |
| 507 | } |
| 508 | else |
| 509 | { |
| 510 | ms_type = mst_file_bss; |
| 511 | } |
| 512 | } |
| 513 | else |
| 514 | { |
| 515 | ms_type = mst_unknown; |
| 516 | } |
| 517 | } |
| 518 | else |
| 519 | { |
| 520 | /* FIXME: Solaris2 shared libraries include lots of |
| 521 | odd "absolute" and "undefined" symbols, that play |
| 522 | hob with actions like finding what function the PC |
| 523 | is in. Ignore them if they aren't text, data, or bss. */ |
| 524 | /* ms_type = mst_unknown; */ |
| 525 | continue; /* Skip this symbol. */ |
| 526 | } |
| 527 | /* Pass symbol size field in via BFD. FIXME!!! */ |
| 528 | size = ((elf_symbol_type *) sym)->internal_elf_sym.st_size; |
| 529 | msym = record_minimal_symbol_and_info |
| 530 | ((char *) sym->name, symaddr, |
| 531 | ms_type, (PTR) size, sym->section, objfile); |
| 532 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 533 | if (msym != NULL) |
| 534 | msym->filename = filesymname; |
| 535 | #endif |
| 536 | #ifdef ELF_MAKE_MSYMBOL_SPECIAL |
| 537 | ELF_MAKE_MSYMBOL_SPECIAL (sym, msym); |
| 538 | #endif |
| 539 | } |
| 540 | } |
| 541 | do_cleanups (back_to); |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | /* Scan and build partial symbols for a symbol file. |
| 546 | We have been initialized by a call to elf_symfile_init, which |
| 547 | currently does nothing. |
| 548 | |
| 549 | SECTION_OFFSETS is a set of offsets to apply to relocate the symbols |
| 550 | in each section. We simplify it down to a single offset for all |
| 551 | symbols. FIXME. |
| 552 | |
| 553 | MAINLINE is true if we are reading the main symbol |
| 554 | table (as opposed to a shared lib or dynamically loaded file). |
| 555 | |
| 556 | This function only does the minimum work necessary for letting the |
| 557 | user "name" things symbolically; it does not read the entire symtab. |
| 558 | Instead, it reads the external and static symbols and puts them in partial |
| 559 | symbol tables. When more extensive information is requested of a |
| 560 | file, the corresponding partial symbol table is mutated into a full |
| 561 | fledged symbol table by going back and reading the symbols |
| 562 | for real. |
| 563 | |
| 564 | We look for sections with specific names, to tell us what debug |
| 565 | format to look for: FIXME!!! |
| 566 | |
| 567 | dwarf_build_psymtabs() builds psymtabs for DWARF symbols; |
| 568 | elfstab_build_psymtabs() handles STABS symbols; |
| 569 | mdebug_build_psymtabs() handles ECOFF debugging information. |
| 570 | |
| 571 | Note that ELF files have a "minimal" symbol table, which looks a lot |
| 572 | like a COFF symbol table, but has only the minimal information necessary |
| 573 | for linking. We process this also, and use the information to |
| 574 | build gdb's minimal symbol table. This gives us some minimal debugging |
| 575 | capability even for files compiled without -g. */ |
| 576 | |
| 577 | static void |
| 578 | elf_symfile_read (struct objfile *objfile, int mainline) |
| 579 | { |
| 580 | bfd *abfd = objfile->obfd; |
| 581 | struct elfinfo ei; |
| 582 | struct cleanup *back_to; |
| 583 | CORE_ADDR offset; |
| 584 | |
| 585 | init_minimal_symbol_collection (); |
| 586 | back_to = make_cleanup_discard_minimal_symbols (); |
| 587 | |
| 588 | memset ((char *) &ei, 0, sizeof (ei)); |
| 589 | |
| 590 | /* Allocate struct to keep track of the symfile */ |
| 591 | objfile->sym_stab_info = (struct dbx_symfile_info *) |
| 592 | xmmalloc (objfile->md, sizeof (struct dbx_symfile_info)); |
| 593 | memset ((char *) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info)); |
| 594 | make_cleanup (free_elfinfo, (PTR) objfile); |
| 595 | |
| 596 | /* Process the normal ELF symbol table first. This may write some |
| 597 | chain of info into the dbx_symfile_info in objfile->sym_stab_info, |
| 598 | which can later be used by elfstab_offset_sections. */ |
| 599 | |
| 600 | elf_symtab_read (objfile, 0); |
| 601 | |
| 602 | /* Add the dynamic symbols. */ |
| 603 | |
| 604 | elf_symtab_read (objfile, 1); |
| 605 | |
| 606 | /* Now process debugging information, which is contained in |
| 607 | special ELF sections. */ |
| 608 | |
| 609 | /* If we are reinitializing, or if we have never loaded syms yet, |
| 610 | set table to empty. MAINLINE is cleared so that *_read_psymtab |
| 611 | functions do not all also re-initialize the psymbol table. */ |
| 612 | if (mainline) |
| 613 | { |
| 614 | init_psymbol_list (objfile, 0); |
| 615 | mainline = 0; |
| 616 | } |
| 617 | |
| 618 | /* We first have to find them... */ |
| 619 | bfd_map_over_sections (abfd, elf_locate_sections, (PTR) & ei); |
| 620 | |
| 621 | /* ELF debugging information is inserted into the psymtab in the |
| 622 | order of least informative first - most informative last. Since |
| 623 | the psymtab table is searched `most recent insertion first' this |
| 624 | increases the probability that more detailed debug information |
| 625 | for a section is found. |
| 626 | |
| 627 | For instance, an object file might contain both .mdebug (XCOFF) |
| 628 | and .debug_info (DWARF2) sections then .mdebug is inserted first |
| 629 | (searched last) and DWARF2 is inserted last (searched first). If |
| 630 | we don't do this then the XCOFF info is found first - for code in |
| 631 | an included file XCOFF info is useless. */ |
| 632 | |
| 633 | if (ei.mdebugsect) |
| 634 | { |
| 635 | const struct ecoff_debug_swap *swap; |
| 636 | |
| 637 | /* .mdebug section, presumably holding ECOFF debugging |
| 638 | information. */ |
| 639 | swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; |
| 640 | if (swap) |
| 641 | elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect); |
| 642 | } |
| 643 | if (ei.stabsect) |
| 644 | { |
| 645 | asection *str_sect; |
| 646 | |
| 647 | /* Stab sections have an associated string table that looks like |
| 648 | a separate section. */ |
| 649 | str_sect = bfd_get_section_by_name (abfd, ".stabstr"); |
| 650 | |
| 651 | /* FIXME should probably warn about a stab section without a stabstr. */ |
| 652 | if (str_sect) |
| 653 | elfstab_build_psymtabs (objfile, |
| 654 | mainline, |
| 655 | ei.stabsect->filepos, |
| 656 | bfd_section_size (abfd, ei.stabsect), |
| 657 | str_sect->filepos, |
| 658 | bfd_section_size (abfd, str_sect)); |
| 659 | } |
| 660 | if (dwarf2_has_info (abfd)) |
| 661 | { |
| 662 | /* DWARF 2 sections */ |
| 663 | dwarf2_build_psymtabs (objfile, mainline); |
| 664 | } |
| 665 | else if (ei.dboffset && ei.lnoffset) |
| 666 | { |
| 667 | /* DWARF sections */ |
| 668 | dwarf_build_psymtabs (objfile, |
| 669 | mainline, |
| 670 | ei.dboffset, ei.dbsize, |
| 671 | ei.lnoffset, ei.lnsize); |
| 672 | } |
| 673 | |
| 674 | /* Install any minimal symbols that have been collected as the current |
| 675 | minimal symbols for this objfile. */ |
| 676 | |
| 677 | install_minimal_symbols (objfile); |
| 678 | |
| 679 | do_cleanups (back_to); |
| 680 | } |
| 681 | |
| 682 | /* This cleans up the objfile's sym_stab_info pointer, and the chain of |
| 683 | stab_section_info's, that might be dangling from it. */ |
| 684 | |
| 685 | static void |
| 686 | free_elfinfo (PTR objp) |
| 687 | { |
| 688 | struct objfile *objfile = (struct objfile *) objp; |
| 689 | struct dbx_symfile_info *dbxinfo = objfile->sym_stab_info; |
| 690 | struct stab_section_info *ssi, *nssi; |
| 691 | |
| 692 | ssi = dbxinfo->stab_section_info; |
| 693 | while (ssi) |
| 694 | { |
| 695 | nssi = ssi->next; |
| 696 | mfree (objfile->md, ssi); |
| 697 | ssi = nssi; |
| 698 | } |
| 699 | |
| 700 | dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ |
| 701 | } |
| 702 | |
| 703 | |
| 704 | /* Initialize anything that needs initializing when a completely new symbol |
| 705 | file is specified (not just adding some symbols from another file, e.g. a |
| 706 | shared library). |
| 707 | |
| 708 | We reinitialize buildsym, since we may be reading stabs from an ELF file. */ |
| 709 | |
| 710 | static void |
| 711 | elf_new_init (struct objfile *ignore) |
| 712 | { |
| 713 | stabsread_new_init (); |
| 714 | buildsym_new_init (); |
| 715 | } |
| 716 | |
| 717 | /* Perform any local cleanups required when we are done with a particular |
| 718 | objfile. I.E, we are in the process of discarding all symbol information |
| 719 | for an objfile, freeing up all memory held for it, and unlinking the |
| 720 | objfile struct from the global list of known objfiles. */ |
| 721 | |
| 722 | static void |
| 723 | elf_symfile_finish (struct objfile *objfile) |
| 724 | { |
| 725 | if (objfile->sym_stab_info != NULL) |
| 726 | { |
| 727 | mfree (objfile->md, objfile->sym_stab_info); |
| 728 | } |
| 729 | } |
| 730 | |
| 731 | /* ELF specific initialization routine for reading symbols. |
| 732 | |
| 733 | It is passed a pointer to a struct sym_fns which contains, among other |
| 734 | things, the BFD for the file whose symbols are being read, and a slot for |
| 735 | a pointer to "private data" which we can fill with goodies. |
| 736 | |
| 737 | For now at least, we have nothing in particular to do, so this function is |
| 738 | just a stub. */ |
| 739 | |
| 740 | static void |
| 741 | elf_symfile_init (struct objfile *objfile) |
| 742 | { |
| 743 | /* ELF objects may be reordered, so set OBJF_REORDERED. If we |
| 744 | find this causes a significant slowdown in gdb then we could |
| 745 | set it in the debug symbol readers only when necessary. */ |
| 746 | objfile->flags |= OBJF_REORDERED; |
| 747 | } |
| 748 | |
| 749 | /* When handling an ELF file that contains Sun STABS debug info, |
| 750 | some of the debug info is relative to the particular chunk of the |
| 751 | section that was generated in its individual .o file. E.g. |
| 752 | offsets to static variables are relative to the start of the data |
| 753 | segment *for that module before linking*. This information is |
| 754 | painfully squirreled away in the ELF symbol table as local symbols |
| 755 | with wierd names. Go get 'em when needed. */ |
| 756 | |
| 757 | void |
| 758 | elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst) |
| 759 | { |
| 760 | char *filename = pst->filename; |
| 761 | struct dbx_symfile_info *dbx = objfile->sym_stab_info; |
| 762 | struct stab_section_info *maybe = dbx->stab_section_info; |
| 763 | struct stab_section_info *questionable = 0; |
| 764 | int i; |
| 765 | char *p; |
| 766 | |
| 767 | /* The ELF symbol info doesn't include path names, so strip the path |
| 768 | (if any) from the psymtab filename. */ |
| 769 | while (0 != (p = strchr (filename, '/'))) |
| 770 | filename = p + 1; |
| 771 | |
| 772 | /* FIXME: This linear search could speed up significantly |
| 773 | if it was chained in the right order to match how we search it, |
| 774 | and if we unchained when we found a match. */ |
| 775 | for (; maybe; maybe = maybe->next) |
| 776 | { |
| 777 | if (filename[0] == maybe->filename[0] |
| 778 | && STREQ (filename, maybe->filename)) |
| 779 | { |
| 780 | /* We found a match. But there might be several source files |
| 781 | (from different directories) with the same name. */ |
| 782 | if (0 == maybe->found) |
| 783 | break; |
| 784 | questionable = maybe; /* Might use it later. */ |
| 785 | } |
| 786 | } |
| 787 | |
| 788 | if (maybe == 0 && questionable != 0) |
| 789 | { |
| 790 | complain (&stab_info_questionable_complaint, filename); |
| 791 | maybe = questionable; |
| 792 | } |
| 793 | |
| 794 | if (maybe) |
| 795 | { |
| 796 | /* Found it! Allocate a new psymtab struct, and fill it in. */ |
| 797 | maybe->found++; |
| 798 | pst->section_offsets = (struct section_offsets *) |
| 799 | obstack_alloc (&objfile->psymbol_obstack, SIZEOF_SECTION_OFFSETS); |
| 800 | for (i = 0; i < SECT_OFF_MAX; i++) |
| 801 | (pst->section_offsets)->offsets[i] = maybe->sections[i]; |
| 802 | return; |
| 803 | } |
| 804 | |
| 805 | /* We were unable to find any offsets for this file. Complain. */ |
| 806 | if (dbx->stab_section_info) /* If there *is* any info, */ |
| 807 | complain (&stab_info_mismatch_complaint, filename); |
| 808 | } |
| 809 | \f |
| 810 | /* Register that we are able to handle ELF object file formats. */ |
| 811 | |
| 812 | static struct sym_fns elf_sym_fns = |
| 813 | { |
| 814 | bfd_target_elf_flavour, |
| 815 | elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ |
| 816 | elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ |
| 817 | elf_symfile_read, /* sym_read: read a symbol file into symtab */ |
| 818 | elf_symfile_finish, /* sym_finish: finished with file, cleanup */ |
| 819 | default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */ |
| 820 | NULL /* next: pointer to next struct sym_fns */ |
| 821 | }; |
| 822 | |
| 823 | void |
| 824 | _initialize_elfread (void) |
| 825 | { |
| 826 | add_symtab_fns (&elf_sym_fns); |
| 827 | } |