| 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, Boston, MA 02111-1307, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "bfd.h" |
| 23 | #include "gdb_string.h" |
| 24 | #include "elf-bfd.h" |
| 25 | #include "elf/mips.h" |
| 26 | #include "symtab.h" |
| 27 | #include "symfile.h" |
| 28 | #include "objfiles.h" |
| 29 | #include "buildsym.h" |
| 30 | #include "stabsread.h" |
| 31 | #include "gdb-stabs.h" |
| 32 | #include "complaints.h" |
| 33 | #include "demangle.h" |
| 34 | |
| 35 | /* The struct elfinfo is available only during ELF symbol table and |
| 36 | psymtab reading. It is destroyed at the complation of psymtab-reading. |
| 37 | It's local to elf_symfile_read. */ |
| 38 | |
| 39 | struct elfinfo { |
| 40 | file_ptr dboffset; /* Offset to dwarf debug section */ |
| 41 | unsigned int dbsize; /* Size of dwarf debug section */ |
| 42 | file_ptr lnoffset; /* Offset to dwarf line number section */ |
| 43 | unsigned int lnsize; /* Size of dwarf line number section */ |
| 44 | asection *stabsect; /* Section pointer for .stab section */ |
| 45 | asection *stabindexsect; /* Section pointer for .stab.index section */ |
| 46 | asection *mdebugsect; /* Section pointer for .mdebug section */ |
| 47 | }; |
| 48 | |
| 49 | /* Various things we might complain about... */ |
| 50 | |
| 51 | struct complaint section_info_complaint = |
| 52 | {"elf/stab section information %s without a preceding file symbol", 0, 0}; |
| 53 | |
| 54 | struct complaint section_info_dup_complaint = |
| 55 | {"duplicated elf/stab section information for %s", 0, 0}; |
| 56 | |
| 57 | struct complaint stab_info_mismatch_complaint = |
| 58 | {"elf/stab section information missing for %s", 0, 0}; |
| 59 | |
| 60 | struct complaint stab_info_questionable_complaint = |
| 61 | {"elf/stab section information questionable for %s", 0, 0}; |
| 62 | |
| 63 | static void |
| 64 | elf_symfile_init PARAMS ((struct objfile *)); |
| 65 | |
| 66 | static void |
| 67 | elf_new_init PARAMS ((struct objfile *)); |
| 68 | |
| 69 | static void |
| 70 | elf_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int)); |
| 71 | |
| 72 | static void |
| 73 | elf_symfile_finish PARAMS ((struct objfile *)); |
| 74 | |
| 75 | static void |
| 76 | elf_symtab_read PARAMS ((bfd *, CORE_ADDR, struct objfile *, int)); |
| 77 | |
| 78 | static void |
| 79 | free_elfinfo PARAMS ((void *)); |
| 80 | |
| 81 | static struct minimal_symbol * |
| 82 | record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR, |
| 83 | enum minimal_symbol_type, char *, |
| 84 | asection *bfd_section, |
| 85 | struct objfile *)); |
| 86 | |
| 87 | static void |
| 88 | elf_locate_sections PARAMS ((bfd *, asection *, void *)); |
| 89 | |
| 90 | /* We are called once per section from elf_symfile_read. We |
| 91 | need to examine each section we are passed, check to see |
| 92 | if it is something we are interested in processing, and |
| 93 | if so, stash away some access information for the section. |
| 94 | |
| 95 | For now we recognize the dwarf debug information sections and |
| 96 | line number sections from matching their section names. The |
| 97 | ELF definition is no real help here since it has no direct |
| 98 | knowledge of DWARF (by design, so any debugging format can be |
| 99 | used). |
| 100 | |
| 101 | We also recognize the ".stab" sections used by the Sun compilers |
| 102 | released with Solaris 2. |
| 103 | |
| 104 | FIXME: The section names should not be hardwired strings (what |
| 105 | should they be? I don't think most object file formats have enough |
| 106 | section flags to specify what kind of debug section it is |
| 107 | -kingdon). */ |
| 108 | |
| 109 | static void |
| 110 | elf_locate_sections (ignore_abfd, sectp, eip) |
| 111 | bfd *ignore_abfd; |
| 112 | asection *sectp; |
| 113 | PTR eip; |
| 114 | { |
| 115 | register struct elfinfo *ei; |
| 116 | |
| 117 | ei = (struct elfinfo *) eip; |
| 118 | if (STREQ (sectp -> name, ".debug")) |
| 119 | { |
| 120 | ei -> dboffset = sectp -> filepos; |
| 121 | ei -> dbsize = bfd_get_section_size_before_reloc (sectp); |
| 122 | } |
| 123 | else if (STREQ (sectp -> name, ".line")) |
| 124 | { |
| 125 | ei -> lnoffset = sectp -> filepos; |
| 126 | ei -> lnsize = bfd_get_section_size_before_reloc (sectp); |
| 127 | } |
| 128 | else if (STREQ (sectp -> name, ".stab")) |
| 129 | { |
| 130 | ei -> stabsect = sectp; |
| 131 | } |
| 132 | else if (STREQ (sectp -> name, ".stab.index")) |
| 133 | { |
| 134 | ei -> stabindexsect = sectp; |
| 135 | } |
| 136 | else if (STREQ (sectp -> name, ".mdebug")) |
| 137 | { |
| 138 | ei -> mdebugsect = sectp; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | #if 0 /* Currently unused */ |
| 143 | |
| 144 | char * |
| 145 | elf_interpreter (abfd) |
| 146 | bfd *abfd; |
| 147 | { |
| 148 | sec_ptr interp_sec; |
| 149 | unsigned size; |
| 150 | char *interp = NULL; |
| 151 | |
| 152 | interp_sec = bfd_get_section_by_name (abfd, ".interp"); |
| 153 | if (interp_sec) |
| 154 | { |
| 155 | size = bfd_section_size (abfd, interp_sec); |
| 156 | interp = alloca (size); |
| 157 | if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0, |
| 158 | size)) |
| 159 | { |
| 160 | interp = savestring (interp, size - 1); |
| 161 | } |
| 162 | else |
| 163 | { |
| 164 | interp = NULL; |
| 165 | } |
| 166 | } |
| 167 | return (interp); |
| 168 | } |
| 169 | |
| 170 | #endif |
| 171 | |
| 172 | static struct minimal_symbol * |
| 173 | record_minimal_symbol_and_info (name, address, ms_type, info, bfd_section, |
| 174 | objfile) |
| 175 | char *name; |
| 176 | CORE_ADDR address; |
| 177 | enum minimal_symbol_type ms_type; |
| 178 | char *info; /* FIXME, is this really char *? */ |
| 179 | asection *bfd_section; |
| 180 | struct objfile *objfile; |
| 181 | { |
| 182 | int section; |
| 183 | |
| 184 | /* Guess the section from the type. This is likely to be wrong in |
| 185 | some cases. */ |
| 186 | switch (ms_type) |
| 187 | { |
| 188 | case mst_text: |
| 189 | case mst_file_text: |
| 190 | section = SECT_OFF_TEXT; |
| 191 | #ifdef SMASH_TEXT_ADDRESS |
| 192 | SMASH_TEXT_ADDRESS (address); |
| 193 | #endif |
| 194 | break; |
| 195 | case mst_data: |
| 196 | case mst_file_data: |
| 197 | section = SECT_OFF_DATA; |
| 198 | break; |
| 199 | case mst_bss: |
| 200 | case mst_file_bss: |
| 201 | section = SECT_OFF_BSS; |
| 202 | break; |
| 203 | default: |
| 204 | section = -1; |
| 205 | break; |
| 206 | } |
| 207 | |
| 208 | return prim_record_minimal_symbol_and_info |
| 209 | (name, address, ms_type, info, section, bfd_section, objfile); |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | |
| 214 | LOCAL FUNCTION |
| 215 | |
| 216 | elf_symtab_read -- read the symbol table of an ELF file |
| 217 | |
| 218 | SYNOPSIS |
| 219 | |
| 220 | void elf_symtab_read (bfd *abfd, CORE_ADDR addr, |
| 221 | struct objfile *objfile, int dynamic) |
| 222 | |
| 223 | DESCRIPTION |
| 224 | |
| 225 | Given an open bfd, a base address to relocate symbols to, and a |
| 226 | flag that specifies whether or not this bfd is for an executable |
| 227 | or not (may be shared library for example), add all the global |
| 228 | function and data symbols to the minimal symbol table. |
| 229 | |
| 230 | In stabs-in-ELF, as implemented by Sun, there are some local symbols |
| 231 | defined in the ELF symbol table, which can be used to locate |
| 232 | the beginnings of sections from each ".o" file that was linked to |
| 233 | form the executable objfile. We gather any such info and record it |
| 234 | in data structures hung off the objfile's private data. |
| 235 | |
| 236 | */ |
| 237 | |
| 238 | static void |
| 239 | elf_symtab_read (abfd, addr, objfile, dynamic) |
| 240 | bfd *abfd; |
| 241 | CORE_ADDR addr; |
| 242 | struct objfile *objfile; |
| 243 | int dynamic; |
| 244 | { |
| 245 | long storage_needed; |
| 246 | asymbol *sym; |
| 247 | asymbol **symbol_table; |
| 248 | long number_of_symbols; |
| 249 | long i; |
| 250 | int index; |
| 251 | struct cleanup *back_to; |
| 252 | CORE_ADDR symaddr; |
| 253 | enum minimal_symbol_type ms_type; |
| 254 | /* If sectinfo is nonNULL, it contains section info that should end up |
| 255 | filed in the objfile. */ |
| 256 | struct stab_section_info *sectinfo = NULL; |
| 257 | /* If filesym is nonzero, it points to a file symbol, but we haven't |
| 258 | seen any section info for it yet. */ |
| 259 | asymbol *filesym = 0; |
| 260 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 261 | /* Name of filesym, as saved on the symbol_obstack. */ |
| 262 | char *filesymname = obsavestring ("", 0, &objfile->symbol_obstack); |
| 263 | #endif |
| 264 | struct dbx_symfile_info *dbx = objfile->sym_stab_info; |
| 265 | unsigned long size; |
| 266 | int stripped = (bfd_get_symcount (abfd) == 0); |
| 267 | |
| 268 | if (dynamic) |
| 269 | { |
| 270 | storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd); |
| 271 | |
| 272 | /* Nothing to be done if there is no dynamic symtab. */ |
| 273 | if (storage_needed < 0) |
| 274 | return; |
| 275 | } |
| 276 | else |
| 277 | { |
| 278 | storage_needed = bfd_get_symtab_upper_bound (abfd); |
| 279 | if (storage_needed < 0) |
| 280 | error ("Can't read symbols from %s: %s", bfd_get_filename (abfd), |
| 281 | bfd_errmsg (bfd_get_error ())); |
| 282 | } |
| 283 | if (storage_needed > 0) |
| 284 | { |
| 285 | symbol_table = (asymbol **) xmalloc (storage_needed); |
| 286 | back_to = make_cleanup (free, symbol_table); |
| 287 | if (dynamic) |
| 288 | number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, |
| 289 | symbol_table); |
| 290 | else |
| 291 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
| 292 | if (number_of_symbols < 0) |
| 293 | error ("Can't read symbols from %s: %s", bfd_get_filename (abfd), |
| 294 | bfd_errmsg (bfd_get_error ())); |
| 295 | for (i = 0; i < number_of_symbols; i++) |
| 296 | { |
| 297 | sym = symbol_table[i]; |
| 298 | if (sym -> name == NULL || *sym -> name == '\0') |
| 299 | { |
| 300 | /* Skip names that don't exist (shouldn't happen), or names |
| 301 | that are null strings (may happen). */ |
| 302 | continue; |
| 303 | } |
| 304 | |
| 305 | if (dynamic |
| 306 | && sym -> section == &bfd_und_section |
| 307 | && (sym -> flags & BSF_FUNCTION)) |
| 308 | { |
| 309 | struct minimal_symbol *msym; |
| 310 | |
| 311 | /* Symbol is a reference to a function defined in |
| 312 | a shared library. |
| 313 | If its value is non zero then it is usually the address |
| 314 | of the corresponding entry in the procedure linkage table, |
| 315 | relative to the base address. |
| 316 | If its value is zero then the dynamic linker has to resolve |
| 317 | the symbol. We are unable to find any meaningful address |
| 318 | for this symbol in the executable file, so we skip it. */ |
| 319 | symaddr = sym -> value; |
| 320 | if (symaddr == 0) |
| 321 | continue; |
| 322 | symaddr += addr; |
| 323 | msym = record_minimal_symbol_and_info |
| 324 | ((char *) sym -> name, symaddr, |
| 325 | mst_solib_trampoline, NULL, sym -> section, objfile); |
| 326 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 327 | if (msym != NULL) |
| 328 | msym->filename = filesymname; |
| 329 | #endif |
| 330 | continue; |
| 331 | } |
| 332 | |
| 333 | /* If it is a nonstripped executable, do not enter dynamic |
| 334 | symbols, as the dynamic symbol table is usually a subset |
| 335 | of the main symbol table. */ |
| 336 | if (dynamic && !stripped) |
| 337 | continue; |
| 338 | if (sym -> flags & BSF_FILE) |
| 339 | { |
| 340 | /* STT_FILE debugging symbol that helps stabs-in-elf debugging. |
| 341 | Chain any old one onto the objfile; remember new sym. */ |
| 342 | if (sectinfo != NULL) |
| 343 | { |
| 344 | sectinfo -> next = dbx -> stab_section_info; |
| 345 | dbx -> stab_section_info = sectinfo; |
| 346 | sectinfo = NULL; |
| 347 | } |
| 348 | filesym = sym; |
| 349 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 350 | filesymname = |
| 351 | obsavestring ((char *)filesym->name, strlen (filesym->name), |
| 352 | &objfile->symbol_obstack); |
| 353 | #endif |
| 354 | } |
| 355 | else if (sym -> flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) |
| 356 | { |
| 357 | struct minimal_symbol *msym; |
| 358 | |
| 359 | /* Select global/local/weak symbols. Note that bfd puts abs |
| 360 | symbols in their own section, so all symbols we are |
| 361 | interested in will have a section. */ |
| 362 | /* Bfd symbols are section relative. */ |
| 363 | symaddr = sym -> value + sym -> section -> vma; |
| 364 | /* Relocate all non-absolute symbols by base address. */ |
| 365 | if (sym -> section != &bfd_abs_section) |
| 366 | { |
| 367 | symaddr += addr; |
| 368 | } |
| 369 | /* For non-absolute symbols, use the type of the section |
| 370 | they are relative to, to intuit text/data. Bfd provides |
| 371 | no way of figuring this out for absolute symbols. */ |
| 372 | if (sym -> section == &bfd_abs_section) |
| 373 | { |
| 374 | /* This is a hack to get the minimal symbol type |
| 375 | right for Irix 5, which has absolute adresses |
| 376 | with special section indices for dynamic symbols. */ |
| 377 | unsigned short shndx = |
| 378 | ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; |
| 379 | |
| 380 | switch (shndx) |
| 381 | { |
| 382 | case SHN_MIPS_TEXT: |
| 383 | ms_type = mst_text; |
| 384 | break; |
| 385 | case SHN_MIPS_DATA: |
| 386 | ms_type = mst_data; |
| 387 | break; |
| 388 | case SHN_MIPS_ACOMMON: |
| 389 | ms_type = mst_bss; |
| 390 | break; |
| 391 | default: |
| 392 | ms_type = mst_abs; |
| 393 | } |
| 394 | |
| 395 | /* If it is an Irix dynamic symbol, skip section name |
| 396 | symbols, relocate all others. */ |
| 397 | if (ms_type != mst_abs) |
| 398 | { |
| 399 | if (sym->name[0] == '.') |
| 400 | continue; |
| 401 | symaddr += addr; |
| 402 | } |
| 403 | } |
| 404 | else if (sym -> section -> flags & SEC_CODE) |
| 405 | { |
| 406 | if (sym -> flags & BSF_GLOBAL) |
| 407 | { |
| 408 | ms_type = mst_text; |
| 409 | } |
| 410 | else if ((sym->name[0] == '.' && sym->name[1] == 'L') |
| 411 | || ((sym -> flags & BSF_LOCAL) |
| 412 | && sym->name[0] == '$' |
| 413 | && sym->name[1] == 'L')) |
| 414 | /* Looks like a compiler-generated label. Skip it. |
| 415 | The assembler should be skipping these (to keep |
| 416 | executables small), but apparently with gcc on the |
| 417 | delta m88k SVR4, it loses. So to have us check too |
| 418 | should be harmless (but I encourage people to fix this |
| 419 | in the assembler instead of adding checks here). */ |
| 420 | continue; |
| 421 | #ifdef HARRIS_TARGET |
| 422 | else if (sym->name[0] == '.' && sym->name[1] == '.') |
| 423 | { |
| 424 | /* Looks like a Harris compiler generated label for the |
| 425 | purpose of marking instructions that are relevant to |
| 426 | DWARF dies. The assembler can't get rid of these |
| 427 | because they are relocatable addresses that the |
| 428 | linker needs to resolve. */ |
| 429 | continue; |
| 430 | } |
| 431 | #endif |
| 432 | else |
| 433 | { |
| 434 | ms_type = mst_file_text; |
| 435 | } |
| 436 | } |
| 437 | else if (sym -> section -> flags & SEC_ALLOC) |
| 438 | { |
| 439 | if (sym -> flags & BSF_GLOBAL) |
| 440 | { |
| 441 | if (sym -> section -> flags & SEC_LOAD) |
| 442 | { |
| 443 | ms_type = mst_data; |
| 444 | } |
| 445 | else |
| 446 | { |
| 447 | ms_type = mst_bss; |
| 448 | } |
| 449 | } |
| 450 | else if (sym -> flags & BSF_LOCAL) |
| 451 | { |
| 452 | /* Named Local variable in a Data section. Check its |
| 453 | name for stabs-in-elf. The STREQ macro checks the |
| 454 | first character inline, so we only actually do a |
| 455 | strcmp function call on names that start with 'B' |
| 456 | or 'D' */ |
| 457 | index = SECT_OFF_MAX; |
| 458 | if (STREQ ("Bbss.bss", sym -> name)) |
| 459 | { |
| 460 | index = SECT_OFF_BSS; |
| 461 | } |
| 462 | else if (STREQ ("Ddata.data", sym -> name)) |
| 463 | { |
| 464 | index = SECT_OFF_DATA; |
| 465 | } |
| 466 | else if (STREQ ("Drodata.rodata", sym -> name)) |
| 467 | { |
| 468 | index = SECT_OFF_RODATA; |
| 469 | } |
| 470 | if (index != SECT_OFF_MAX) |
| 471 | { |
| 472 | /* Found a special local symbol. Allocate a |
| 473 | sectinfo, if needed, and fill it in. */ |
| 474 | if (sectinfo == NULL) |
| 475 | { |
| 476 | sectinfo = (struct stab_section_info *) |
| 477 | xmmalloc (objfile -> md, sizeof (*sectinfo)); |
| 478 | memset ((PTR) sectinfo, 0, sizeof (*sectinfo)); |
| 479 | if (filesym == NULL) |
| 480 | { |
| 481 | complain (§ion_info_complaint, |
| 482 | sym -> name); |
| 483 | } |
| 484 | else |
| 485 | { |
| 486 | sectinfo -> filename = |
| 487 | (char *) filesym -> name; |
| 488 | } |
| 489 | } |
| 490 | if (sectinfo -> sections[index] != 0) |
| 491 | { |
| 492 | complain (§ion_info_dup_complaint, |
| 493 | sectinfo -> filename); |
| 494 | } |
| 495 | /* Bfd symbols are section relative. */ |
| 496 | symaddr = sym -> value + sym -> section -> vma; |
| 497 | /* Relocate non-absolute symbols by base address. */ |
| 498 | if (sym -> section != &bfd_abs_section) |
| 499 | { |
| 500 | symaddr += addr; |
| 501 | } |
| 502 | sectinfo -> sections[index] = symaddr; |
| 503 | /* The special local symbols don't go in the |
| 504 | minimal symbol table, so ignore this one. */ |
| 505 | continue; |
| 506 | } |
| 507 | /* Not a special stabs-in-elf symbol, do regular |
| 508 | symbol processing. */ |
| 509 | if (sym -> section -> flags & SEC_LOAD) |
| 510 | { |
| 511 | ms_type = mst_file_data; |
| 512 | } |
| 513 | else |
| 514 | { |
| 515 | ms_type = mst_file_bss; |
| 516 | } |
| 517 | } |
| 518 | else |
| 519 | { |
| 520 | ms_type = mst_unknown; |
| 521 | } |
| 522 | } |
| 523 | else |
| 524 | { |
| 525 | /* FIXME: Solaris2 shared libraries include lots of |
| 526 | odd "absolute" and "undefined" symbols, that play |
| 527 | hob with actions like finding what function the PC |
| 528 | is in. Ignore them if they aren't text, data, or bss. */ |
| 529 | /* ms_type = mst_unknown; */ |
| 530 | continue; /* Skip this symbol. */ |
| 531 | } |
| 532 | /* Pass symbol size field in via BFD. FIXME!!! */ |
| 533 | size = ((elf_symbol_type *) sym) -> internal_elf_sym.st_size; |
| 534 | msym = record_minimal_symbol_and_info |
| 535 | ((char *) sym -> name, symaddr, |
| 536 | ms_type, (PTR) size, sym -> section, objfile); |
| 537 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 538 | if (msym != NULL) |
| 539 | msym->filename = filesymname; |
| 540 | #endif |
| 541 | #ifdef ELF_MAKE_MSYMBOL_SPECIAL |
| 542 | ELF_MAKE_MSYMBOL_SPECIAL(sym,msym); |
| 543 | #endif |
| 544 | } |
| 545 | } |
| 546 | do_cleanups (back_to); |
| 547 | } |
| 548 | } |
| 549 | |
| 550 | /* Scan and build partial symbols for a symbol file. |
| 551 | We have been initialized by a call to elf_symfile_init, which |
| 552 | currently does nothing. |
| 553 | |
| 554 | SECTION_OFFSETS is a set of offsets to apply to relocate the symbols |
| 555 | in each section. We simplify it down to a single offset for all |
| 556 | symbols. FIXME. |
| 557 | |
| 558 | MAINLINE is true if we are reading the main symbol |
| 559 | table (as opposed to a shared lib or dynamically loaded file). |
| 560 | |
| 561 | This function only does the minimum work necessary for letting the |
| 562 | user "name" things symbolically; it does not read the entire symtab. |
| 563 | Instead, it reads the external and static symbols and puts them in partial |
| 564 | symbol tables. When more extensive information is requested of a |
| 565 | file, the corresponding partial symbol table is mutated into a full |
| 566 | fledged symbol table by going back and reading the symbols |
| 567 | for real. |
| 568 | |
| 569 | We look for sections with specific names, to tell us what debug |
| 570 | format to look for: FIXME!!! |
| 571 | |
| 572 | dwarf_build_psymtabs() builds psymtabs for DWARF symbols; |
| 573 | elfstab_build_psymtabs() handles STABS symbols; |
| 574 | mdebug_build_psymtabs() handles ECOFF debugging information. |
| 575 | |
| 576 | Note that ELF files have a "minimal" symbol table, which looks a lot |
| 577 | like a COFF symbol table, but has only the minimal information necessary |
| 578 | for linking. We process this also, and use the information to |
| 579 | build gdb's minimal symbol table. This gives us some minimal debugging |
| 580 | capability even for files compiled without -g. */ |
| 581 | |
| 582 | static void |
| 583 | elf_symfile_read (objfile, section_offsets, mainline) |
| 584 | struct objfile *objfile; |
| 585 | struct section_offsets *section_offsets; |
| 586 | int mainline; |
| 587 | { |
| 588 | bfd *abfd = objfile->obfd; |
| 589 | struct elfinfo ei; |
| 590 | struct cleanup *back_to; |
| 591 | CORE_ADDR offset; |
| 592 | |
| 593 | init_minimal_symbol_collection (); |
| 594 | back_to = make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0); |
| 595 | |
| 596 | memset ((char *) &ei, 0, sizeof (ei)); |
| 597 | |
| 598 | /* Allocate struct to keep track of the symfile */ |
| 599 | objfile->sym_stab_info = (struct dbx_symfile_info *) |
| 600 | xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info)); |
| 601 | memset ((char *) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info)); |
| 602 | make_cleanup (free_elfinfo, (PTR) objfile); |
| 603 | |
| 604 | /* Process the normal ELF symbol table first. This may write some |
| 605 | chain of info into the dbx_symfile_info in objfile->sym_stab_info, |
| 606 | which can later be used by elfstab_offset_sections. */ |
| 607 | |
| 608 | /* FIXME, should take a section_offsets param, not just an offset. */ |
| 609 | offset = ANOFFSET (section_offsets, 0); |
| 610 | elf_symtab_read (abfd, offset, objfile, 0); |
| 611 | |
| 612 | /* Add the dynamic symbols. */ |
| 613 | |
| 614 | elf_symtab_read (abfd, offset, objfile, 1); |
| 615 | |
| 616 | /* Now process debugging information, which is contained in |
| 617 | special ELF sections. */ |
| 618 | |
| 619 | /* If we are reinitializing, or if we have never loaded syms yet, |
| 620 | set table to empty. MAINLINE is cleared so that *_read_psymtab |
| 621 | functions do not all also re-initialize the psymbol table. */ |
| 622 | if (mainline) |
| 623 | { |
| 624 | init_psymbol_list (objfile, 0); |
| 625 | mainline = 0; |
| 626 | } |
| 627 | |
| 628 | /* We first have to find them... */ |
| 629 | bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei); |
| 630 | |
| 631 | /* ELF debugging information is inserted into the psymtab in the |
| 632 | order of least informative first - most informative last. Since |
| 633 | the psymtab table is searched `most recent insertion first' this |
| 634 | increases the probability that more detailed debug information |
| 635 | for a section is found. |
| 636 | |
| 637 | For instance, an object file might contain both .mdebug (XCOFF) |
| 638 | and .debug_info (DWARF2) sections then .mdebug is inserted first |
| 639 | (searched last) and DWARF2 is inserted last (searched first). If |
| 640 | we don't do this then the XCOFF info is found first - for code in |
| 641 | an included file XCOFF info is useless. */ |
| 642 | |
| 643 | if (ei.mdebugsect) |
| 644 | { |
| 645 | const struct ecoff_debug_swap *swap; |
| 646 | |
| 647 | /* .mdebug section, presumably holding ECOFF debugging |
| 648 | information. */ |
| 649 | swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; |
| 650 | if (swap) |
| 651 | elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect, |
| 652 | section_offsets); |
| 653 | } |
| 654 | if (ei.stabsect) |
| 655 | { |
| 656 | asection *str_sect; |
| 657 | |
| 658 | /* Stab sections have an associated string table that looks like |
| 659 | a separate section. */ |
| 660 | str_sect = bfd_get_section_by_name (abfd, ".stabstr"); |
| 661 | |
| 662 | /* FIXME should probably warn about a stab section without a stabstr. */ |
| 663 | if (str_sect) |
| 664 | elfstab_build_psymtabs (objfile, |
| 665 | section_offsets, |
| 666 | mainline, |
| 667 | ei.stabsect->filepos, |
| 668 | bfd_section_size (abfd, ei.stabsect), |
| 669 | str_sect->filepos, |
| 670 | bfd_section_size (abfd, str_sect)); |
| 671 | } |
| 672 | if (dwarf2_has_info (abfd)) |
| 673 | { |
| 674 | /* DWARF 2 sections */ |
| 675 | dwarf2_build_psymtabs (objfile, section_offsets, mainline); |
| 676 | } |
| 677 | else if (ei.dboffset && ei.lnoffset) |
| 678 | { |
| 679 | /* DWARF sections */ |
| 680 | dwarf_build_psymtabs (objfile, |
| 681 | section_offsets, mainline, |
| 682 | ei.dboffset, ei.dbsize, |
| 683 | ei.lnoffset, ei.lnsize); |
| 684 | } |
| 685 | |
| 686 | /* Install any minimal symbols that have been collected as the current |
| 687 | minimal symbols for this objfile. */ |
| 688 | |
| 689 | install_minimal_symbols (objfile); |
| 690 | |
| 691 | do_cleanups (back_to); |
| 692 | } |
| 693 | |
| 694 | /* This cleans up the objfile's sym_stab_info pointer, and the chain of |
| 695 | stab_section_info's, that might be dangling from it. */ |
| 696 | |
| 697 | static void |
| 698 | free_elfinfo (objp) |
| 699 | PTR objp; |
| 700 | { |
| 701 | struct objfile *objfile = (struct objfile *)objp; |
| 702 | struct dbx_symfile_info *dbxinfo = objfile->sym_stab_info; |
| 703 | struct stab_section_info *ssi, *nssi; |
| 704 | |
| 705 | ssi = dbxinfo->stab_section_info; |
| 706 | while (ssi) |
| 707 | { |
| 708 | nssi = ssi->next; |
| 709 | mfree (objfile->md, ssi); |
| 710 | ssi = nssi; |
| 711 | } |
| 712 | |
| 713 | dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ |
| 714 | } |
| 715 | |
| 716 | |
| 717 | /* Initialize anything that needs initializing when a completely new symbol |
| 718 | file is specified (not just adding some symbols from another file, e.g. a |
| 719 | shared library). |
| 720 | |
| 721 | We reinitialize buildsym, since we may be reading stabs from an ELF file. */ |
| 722 | |
| 723 | static void |
| 724 | elf_new_init (ignore) |
| 725 | struct objfile *ignore; |
| 726 | { |
| 727 | stabsread_new_init (); |
| 728 | buildsym_new_init (); |
| 729 | } |
| 730 | |
| 731 | /* Perform any local cleanups required when we are done with a particular |
| 732 | objfile. I.E, we are in the process of discarding all symbol information |
| 733 | for an objfile, freeing up all memory held for it, and unlinking the |
| 734 | objfile struct from the global list of known objfiles. */ |
| 735 | |
| 736 | static void |
| 737 | elf_symfile_finish (objfile) |
| 738 | struct objfile *objfile; |
| 739 | { |
| 740 | if (objfile -> sym_stab_info != NULL) |
| 741 | { |
| 742 | mfree (objfile -> md, objfile -> sym_stab_info); |
| 743 | } |
| 744 | } |
| 745 | |
| 746 | /* ELF specific initialization routine for reading symbols. |
| 747 | |
| 748 | It is passed a pointer to a struct sym_fns which contains, among other |
| 749 | things, the BFD for the file whose symbols are being read, and a slot for |
| 750 | a pointer to "private data" which we can fill with goodies. |
| 751 | |
| 752 | For now at least, we have nothing in particular to do, so this function is |
| 753 | just a stub. */ |
| 754 | |
| 755 | static void |
| 756 | elf_symfile_init (objfile) |
| 757 | struct objfile *objfile; |
| 758 | { |
| 759 | /* ELF objects may be reordered, so set OBJF_REORDERED. If we |
| 760 | find this causes a significant slowdown in gdb then we could |
| 761 | set it in the debug symbol readers only when necessary. */ |
| 762 | objfile->flags |= OBJF_REORDERED; |
| 763 | } |
| 764 | |
| 765 | /* When handling an ELF file that contains Sun STABS debug info, |
| 766 | some of the debug info is relative to the particular chunk of the |
| 767 | section that was generated in its individual .o file. E.g. |
| 768 | offsets to static variables are relative to the start of the data |
| 769 | segment *for that module before linking*. This information is |
| 770 | painfully squirreled away in the ELF symbol table as local symbols |
| 771 | with wierd names. Go get 'em when needed. */ |
| 772 | |
| 773 | void |
| 774 | elfstab_offset_sections (objfile, pst) |
| 775 | struct objfile *objfile; |
| 776 | struct partial_symtab *pst; |
| 777 | { |
| 778 | char *filename = pst->filename; |
| 779 | struct dbx_symfile_info *dbx = objfile->sym_stab_info; |
| 780 | struct stab_section_info *maybe = dbx->stab_section_info; |
| 781 | struct stab_section_info *questionable = 0; |
| 782 | int i; |
| 783 | char *p; |
| 784 | |
| 785 | /* The ELF symbol info doesn't include path names, so strip the path |
| 786 | (if any) from the psymtab filename. */ |
| 787 | while (0 != (p = strchr (filename, '/'))) |
| 788 | filename = p+1; |
| 789 | |
| 790 | /* FIXME: This linear search could speed up significantly |
| 791 | if it was chained in the right order to match how we search it, |
| 792 | and if we unchained when we found a match. */ |
| 793 | for (; maybe; maybe = maybe->next) |
| 794 | { |
| 795 | if (filename[0] == maybe->filename[0] |
| 796 | && STREQ (filename, maybe->filename)) |
| 797 | { |
| 798 | /* We found a match. But there might be several source files |
| 799 | (from different directories) with the same name. */ |
| 800 | if (0 == maybe->found) |
| 801 | break; |
| 802 | questionable = maybe; /* Might use it later. */ |
| 803 | } |
| 804 | } |
| 805 | |
| 806 | if (maybe == 0 && questionable != 0) |
| 807 | { |
| 808 | complain (&stab_info_questionable_complaint, filename); |
| 809 | maybe = questionable; |
| 810 | } |
| 811 | |
| 812 | if (maybe) |
| 813 | { |
| 814 | /* Found it! Allocate a new psymtab struct, and fill it in. */ |
| 815 | maybe->found++; |
| 816 | pst->section_offsets = (struct section_offsets *) |
| 817 | obstack_alloc (&objfile -> psymbol_obstack, |
| 818 | sizeof (struct section_offsets) + |
| 819 | sizeof (pst->section_offsets->offsets) * (SECT_OFF_MAX-1)); |
| 820 | |
| 821 | for (i = 0; i < SECT_OFF_MAX; i++) |
| 822 | ANOFFSET (pst->section_offsets, i) = maybe->sections[i]; |
| 823 | return; |
| 824 | } |
| 825 | |
| 826 | /* We were unable to find any offsets for this file. Complain. */ |
| 827 | if (dbx->stab_section_info) /* If there *is* any info, */ |
| 828 | complain (&stab_info_mismatch_complaint, filename); |
| 829 | } |
| 830 | \f |
| 831 | /* Register that we are able to handle ELF object file formats. */ |
| 832 | |
| 833 | static struct sym_fns elf_sym_fns = |
| 834 | { |
| 835 | bfd_target_elf_flavour, |
| 836 | elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ |
| 837 | elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ |
| 838 | elf_symfile_read, /* sym_read: read a symbol file into symtab */ |
| 839 | elf_symfile_finish, /* sym_finish: finished with file, cleanup */ |
| 840 | default_symfile_offsets, |
| 841 | /* sym_offsets: Translate ext. to int. relocation */ |
| 842 | NULL /* next: pointer to next struct sym_fns */ |
| 843 | }; |
| 844 | |
| 845 | void |
| 846 | _initialize_elfread () |
| 847 | { |
| 848 | add_symtab_fns (&elf_sym_fns); |
| 849 | } |