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 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 if (bfd_get_section_size (sect) > 0 && j == num_segments) 118 warning (_("Loadable segment \"%s\" outside of ELF segments"), 119 bfd_section_name (abfd, sect)); 120 } 121 122 return data; 123 } 124 125 /* We are called once per section from elf_symfile_read. We 126 need to examine each section we are passed, check to see 127 if it is something we are interested in processing, and 128 if so, stash away some access information for the section. 129 130 For now we recognize the dwarf debug information sections and 131 line number sections from matching their section names. The 132 ELF definition is no real help here since it has no direct 133 knowledge of DWARF (by design, so any debugging format can be 134 used). 135 136 We also recognize the ".stab" sections used by the Sun compilers 137 released with Solaris 2. 138 139 FIXME: The section names should not be hardwired strings (what 140 should they be? I don't think most object file formats have enough 141 section flags to specify what kind of debug section it is 142 -kingdon). */ 143 144 static void 145 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip) 146 { 147 struct elfinfo *ei; 148 149 ei = (struct elfinfo *) eip; 150 if (strcmp (sectp->name, ".stab") == 0) 151 { 152 ei->stabsect = sectp; 153 } 154 else if (strcmp (sectp->name, ".stab.index") == 0) 155 { 156 ei->stabindexsect = sectp; 157 } 158 else if (strcmp (sectp->name, ".mdebug") == 0) 159 { 160 ei->mdebugsect = sectp; 161 } 162 } 163 164 static struct minimal_symbol * 165 record_minimal_symbol (char *name, CORE_ADDR address, 166 enum minimal_symbol_type ms_type, 167 asection *bfd_section, struct objfile *objfile) 168 { 169 struct gdbarch *gdbarch = get_objfile_arch (objfile); 170 171 if (ms_type == mst_text || ms_type == mst_file_text) 172 address = gdbarch_smash_text_address (gdbarch, address); 173 174 return prim_record_minimal_symbol_and_info 175 (name, address, ms_type, bfd_section->index, bfd_section, objfile); 176 } 177 178 /* 179 180 LOCAL FUNCTION 181 182 elf_symtab_read -- read the symbol table of an ELF file 183 184 SYNOPSIS 185 186 void elf_symtab_read (struct objfile *objfile, int type, 187 long number_of_symbols, asymbol **symbol_table) 188 189 DESCRIPTION 190 191 Given an objfile, a symbol table, and a flag indicating whether the 192 symbol table contains regular, dynamic, or synthetic symbols, add all 193 the global function and data symbols to the minimal symbol table. 194 195 In stabs-in-ELF, as implemented by Sun, there are some local symbols 196 defined in the ELF symbol table, which can be used to locate 197 the beginnings of sections from each ".o" file that was linked to 198 form the executable objfile. We gather any such info and record it 199 in data structures hung off the objfile's private data. 200 201 */ 202 203 #define ST_REGULAR 0 204 #define ST_DYNAMIC 1 205 #define ST_SYNTHETIC 2 206 207 static void 208 elf_symtab_read (struct objfile *objfile, int type, 209 long number_of_symbols, asymbol **symbol_table) 210 { 211 struct gdbarch *gdbarch = get_objfile_arch (objfile); 212 long storage_needed; 213 asymbol *sym; 214 long i; 215 CORE_ADDR symaddr; 216 CORE_ADDR offset; 217 enum minimal_symbol_type ms_type; 218 /* If sectinfo is nonNULL, it contains section info that should end up 219 filed in the objfile. */ 220 struct stab_section_info *sectinfo = NULL; 221 /* If filesym is nonzero, it points to a file symbol, but we haven't 222 seen any section info for it yet. */ 223 asymbol *filesym = 0; 224 /* Name of filesym, as saved on the objfile_obstack. */ 225 char *filesymname = obsavestring ("", 0, &objfile->objfile_obstack); 226 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; 227 int stripped = (bfd_get_symcount (objfile->obfd) == 0); 228 229 for (i = 0; i < number_of_symbols; i++) 230 { 231 sym = symbol_table[i]; 232 if (sym->name == NULL || *sym->name == '\0') 233 { 234 /* Skip names that don't exist (shouldn't happen), or names 235 that are null strings (may happen). */ 236 continue; 237 } 238 239 /* Skip "special" symbols, e.g. ARM mapping symbols. These are 240 symbols which do not correspond to objects in the symbol table, 241 but have some other target-specific meaning. */ 242 if (bfd_is_target_special_symbol (objfile->obfd, sym)) 243 { 244 if (gdbarch_record_special_symbol_p (gdbarch)) 245 gdbarch_record_special_symbol (gdbarch, objfile, sym); 246 continue; 247 } 248 249 offset = ANOFFSET (objfile->section_offsets, sym->section->index); 250 if (type == ST_DYNAMIC 251 && sym->section == &bfd_und_section 252 && (sym->flags & BSF_FUNCTION)) 253 { 254 struct minimal_symbol *msym; 255 bfd *abfd = objfile->obfd; 256 asection *sect; 257 258 /* Symbol is a reference to a function defined in 259 a shared library. 260 If its value is non zero then it is usually the address 261 of the corresponding entry in the procedure linkage table, 262 plus the desired section offset. 263 If its value is zero then the dynamic linker has to resolve 264 the symbol. We are unable to find any meaningful address 265 for this symbol in the executable file, so we skip it. */ 266 symaddr = sym->value; 267 if (symaddr == 0) 268 continue; 269 270 /* sym->section is the undefined section. However, we want to 271 record the section where the PLT stub resides with the 272 minimal symbol. Search the section table for the one that 273 covers the stub's address. */ 274 for (sect = abfd->sections; sect != NULL; sect = sect->next) 275 { 276 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) 277 continue; 278 279 if (symaddr >= bfd_get_section_vma (abfd, sect) 280 && symaddr < bfd_get_section_vma (abfd, sect) 281 + bfd_get_section_size (sect)) 282 break; 283 } 284 if (!sect) 285 continue; 286 287 symaddr += ANOFFSET (objfile->section_offsets, sect->index); 288 289 msym = record_minimal_symbol 290 ((char *) sym->name, symaddr, mst_solib_trampoline, sect, objfile); 291 if (msym != NULL) 292 msym->filename = filesymname; 293 continue; 294 } 295 296 /* If it is a nonstripped executable, do not enter dynamic 297 symbols, as the dynamic symbol table is usually a subset 298 of the main symbol table. */ 299 if (type == ST_DYNAMIC && !stripped) 300 continue; 301 if (sym->flags & BSF_FILE) 302 { 303 /* STT_FILE debugging symbol that helps stabs-in-elf debugging. 304 Chain any old one onto the objfile; remember new sym. */ 305 if (sectinfo != NULL) 306 { 307 sectinfo->next = dbx->stab_section_info; 308 dbx->stab_section_info = sectinfo; 309 sectinfo = NULL; 310 } 311 filesym = sym; 312 filesymname = 313 obsavestring ((char *) filesym->name, strlen (filesym->name), 314 &objfile->objfile_obstack); 315 } 316 else if (sym->flags & BSF_SECTION_SYM) 317 continue; 318 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) 319 { 320 struct minimal_symbol *msym; 321 322 /* Select global/local/weak symbols. Note that bfd puts abs 323 symbols in their own section, so all symbols we are 324 interested in will have a section. */ 325 /* Bfd symbols are section relative. */ 326 symaddr = sym->value + sym->section->vma; 327 /* Relocate all non-absolute and non-TLS symbols by the 328 section offset. */ 329 if (sym->section != &bfd_abs_section 330 && !(sym->section->flags & SEC_THREAD_LOCAL)) 331 { 332 symaddr += offset; 333 } 334 /* For non-absolute symbols, use the type of the section 335 they are relative to, to intuit text/data. Bfd provides 336 no way of figuring this out for absolute symbols. */ 337 if (sym->section == &bfd_abs_section) 338 { 339 /* This is a hack to get the minimal symbol type 340 right for Irix 5, which has absolute addresses 341 with special section indices for dynamic symbols. 342 343 NOTE: uweigand-20071112: Synthetic symbols do not 344 have an ELF-private part, so do not touch those. */ 345 unsigned int shndx = type == ST_SYNTHETIC ? 0 : 346 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; 347 348 switch (shndx) 349 { 350 case SHN_MIPS_TEXT: 351 ms_type = mst_text; 352 break; 353 case SHN_MIPS_DATA: 354 ms_type = mst_data; 355 break; 356 case SHN_MIPS_ACOMMON: 357 ms_type = mst_bss; 358 break; 359 default: 360 ms_type = mst_abs; 361 } 362 363 /* If it is an Irix dynamic symbol, skip section name 364 symbols, relocate all others by section offset. */ 365 if (ms_type != mst_abs) 366 { 367 if (sym->name[0] == '.') 368 continue; 369 symaddr += offset; 370 } 371 } 372 else if (sym->section->flags & SEC_CODE) 373 { 374 if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) 375 { 376 ms_type = mst_text; 377 } 378 else if ((sym->name[0] == '.' && sym->name[1] == 'L') 379 || ((sym->flags & BSF_LOCAL) 380 && sym->name[0] == '$' 381 && sym->name[1] == 'L')) 382 /* Looks like a compiler-generated label. Skip 383 it. The assembler should be skipping these (to 384 keep executables small), but apparently with 385 gcc on the (deleted) delta m88k SVR4, it loses. 386 So to have us check too should be harmless (but 387 I encourage people to fix this in the assembler 388 instead of adding checks here). */ 389 continue; 390 else 391 { 392 ms_type = mst_file_text; 393 } 394 } 395 else if (sym->section->flags & SEC_ALLOC) 396 { 397 if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) 398 { 399 if (sym->section->flags & SEC_LOAD) 400 { 401 ms_type = mst_data; 402 } 403 else 404 { 405 ms_type = mst_bss; 406 } 407 } 408 else if (sym->flags & BSF_LOCAL) 409 { 410 /* Named Local variable in a Data section. 411 Check its name for stabs-in-elf. */ 412 int special_local_sect; 413 if (strcmp ("Bbss.bss", sym->name) == 0) 414 special_local_sect = SECT_OFF_BSS (objfile); 415 else if (strcmp ("Ddata.data", sym->name) == 0) 416 special_local_sect = SECT_OFF_DATA (objfile); 417 else if (strcmp ("Drodata.rodata", sym->name) == 0) 418 special_local_sect = SECT_OFF_RODATA (objfile); 419 else 420 special_local_sect = -1; 421 if (special_local_sect >= 0) 422 { 423 /* Found a special local symbol. Allocate a 424 sectinfo, if needed, and fill it in. */ 425 if (sectinfo == NULL) 426 { 427 int max_index; 428 size_t size; 429 430 max_index = SECT_OFF_BSS (objfile); 431 if (objfile->sect_index_data > max_index) 432 max_index = objfile->sect_index_data; 433 if (objfile->sect_index_rodata > max_index) 434 max_index = objfile->sect_index_rodata; 435 436 /* max_index is the largest index we'll 437 use into this array, so we must 438 allocate max_index+1 elements for it. 439 However, 'struct stab_section_info' 440 already includes one element, so we 441 need to allocate max_index aadditional 442 elements. */ 443 size = (sizeof (struct stab_section_info) 444 + (sizeof (CORE_ADDR) 445 * max_index)); 446 sectinfo = (struct stab_section_info *) 447 xmalloc (size); 448 memset (sectinfo, 0, size); 449 sectinfo->num_sections = max_index; 450 if (filesym == NULL) 451 { 452 complaint (&symfile_complaints, 453 _("elf/stab section information %s without a preceding file symbol"), 454 sym->name); 455 } 456 else 457 { 458 sectinfo->filename = 459 (char *) filesym->name; 460 } 461 } 462 if (sectinfo->sections[special_local_sect] != 0) 463 complaint (&symfile_complaints, 464 _("duplicated elf/stab section information for %s"), 465 sectinfo->filename); 466 /* BFD symbols are section relative. */ 467 symaddr = sym->value + sym->section->vma; 468 /* Relocate non-absolute symbols by the 469 section offset. */ 470 if (sym->section != &bfd_abs_section) 471 symaddr += offset; 472 sectinfo->sections[special_local_sect] = symaddr; 473 /* The special local symbols don't go in the 474 minimal symbol table, so ignore this one. */ 475 continue; 476 } 477 /* Not a special stabs-in-elf symbol, do regular 478 symbol processing. */ 479 if (sym->section->flags & SEC_LOAD) 480 { 481 ms_type = mst_file_data; 482 } 483 else 484 { 485 ms_type = mst_file_bss; 486 } 487 } 488 else 489 { 490 ms_type = mst_unknown; 491 } 492 } 493 else 494 { 495 /* FIXME: Solaris2 shared libraries include lots of 496 odd "absolute" and "undefined" symbols, that play 497 hob with actions like finding what function the PC 498 is in. Ignore them if they aren't text, data, or bss. */ 499 /* ms_type = mst_unknown; */ 500 continue; /* Skip this symbol. */ 501 } 502 msym = record_minimal_symbol 503 ((char *) sym->name, symaddr, 504 ms_type, sym->section, objfile); 505 506 if (msym) 507 { 508 /* Pass symbol size field in via BFD. FIXME!!! */ 509 elf_symbol_type *elf_sym; 510 511 /* NOTE: uweigand-20071112: A synthetic symbol does not have an 512 ELF-private part. However, in some cases (e.g. synthetic 513 'dot' symbols on ppc64) the udata.p entry is set to point back 514 to the original ELF symbol it was derived from. Get the size 515 from that symbol. */ 516 if (type != ST_SYNTHETIC) 517 elf_sym = (elf_symbol_type *) sym; 518 else 519 elf_sym = (elf_symbol_type *) sym->udata.p; 520 521 if (elf_sym) 522 MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size; 523 } 524 if (msym != NULL) 525 msym->filename = filesymname; 526 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym); 527 528 /* For @plt symbols, also record a trampoline to the 529 destination symbol. The @plt symbol will be used in 530 disassembly, and the trampoline will be used when we are 531 trying to find the target. */ 532 if (msym && ms_type == mst_text && type == ST_SYNTHETIC) 533 { 534 int len = strlen (sym->name); 535 536 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0) 537 { 538 char *base_name = alloca (len - 4 + 1); 539 struct minimal_symbol *mtramp; 540 541 memcpy (base_name, sym->name, len - 4); 542 base_name[len - 4] = '\0'; 543 mtramp = record_minimal_symbol (base_name, symaddr, 544 mst_solib_trampoline, 545 sym->section, objfile); 546 if (mtramp) 547 { 548 MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym); 549 mtramp->filename = filesymname; 550 gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp); 551 } 552 } 553 } 554 } 555 } 556 } 557 558 /* Scan and build partial symbols for a symbol file. 559 We have been initialized by a call to elf_symfile_init, which 560 currently does nothing. 561 562 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols 563 in each section. We simplify it down to a single offset for all 564 symbols. FIXME. 565 566 MAINLINE is true if we are reading the main symbol 567 table (as opposed to a shared lib or dynamically loaded file). 568 569 This function only does the minimum work necessary for letting the 570 user "name" things symbolically; it does not read the entire symtab. 571 Instead, it reads the external and static symbols and puts them in partial 572 symbol tables. When more extensive information is requested of a 573 file, the corresponding partial symbol table is mutated into a full 574 fledged symbol table by going back and reading the symbols 575 for real. 576 577 We look for sections with specific names, to tell us what debug 578 format to look for: FIXME!!! 579 580 elfstab_build_psymtabs() handles STABS symbols; 581 mdebug_build_psymtabs() handles ECOFF debugging information. 582 583 Note that ELF files have a "minimal" symbol table, which looks a lot 584 like a COFF symbol table, but has only the minimal information necessary 585 for linking. We process this also, and use the information to 586 build gdb's minimal symbol table. This gives us some minimal debugging 587 capability even for files compiled without -g. */ 588 589 static void 590 elf_symfile_read (struct objfile *objfile, int mainline) 591 { 592 bfd *abfd = objfile->obfd; 593 struct elfinfo ei; 594 struct cleanup *back_to; 595 CORE_ADDR offset; 596 long symcount = 0, dynsymcount = 0, synthcount, storage_needed; 597 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL; 598 asymbol *synthsyms; 599 600 init_minimal_symbol_collection (); 601 back_to = make_cleanup_discard_minimal_symbols (); 602 603 memset ((char *) &ei, 0, sizeof (ei)); 604 605 /* Allocate struct to keep track of the symfile */ 606 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *) 607 xmalloc (sizeof (struct dbx_symfile_info)); 608 memset ((char *) objfile->deprecated_sym_stab_info, 0, sizeof (struct dbx_symfile_info)); 609 make_cleanup (free_elfinfo, (void *) objfile); 610 611 /* Process the normal ELF symbol table first. This may write some 612 chain of info into the dbx_symfile_info in objfile->deprecated_sym_stab_info, 613 which can later be used by elfstab_offset_sections. */ 614 615 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd); 616 if (storage_needed < 0) 617 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), 618 bfd_errmsg (bfd_get_error ())); 619 620 if (storage_needed > 0) 621 { 622 symbol_table = (asymbol **) xmalloc (storage_needed); 623 make_cleanup (xfree, symbol_table); 624 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table); 625 626 if (symcount < 0) 627 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), 628 bfd_errmsg (bfd_get_error ())); 629 630 elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table); 631 } 632 633 /* Add the dynamic symbols. */ 634 635 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd); 636 637 if (storage_needed > 0) 638 { 639 dyn_symbol_table = (asymbol **) xmalloc (storage_needed); 640 make_cleanup (xfree, dyn_symbol_table); 641 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd, 642 dyn_symbol_table); 643 644 if (dynsymcount < 0) 645 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), 646 bfd_errmsg (bfd_get_error ())); 647 648 elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table); 649 } 650 651 /* Add synthetic symbols - for instance, names for any PLT entries. */ 652 653 synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table, 654 dynsymcount, dyn_symbol_table, 655 &synthsyms); 656 if (synthcount > 0) 657 { 658 asymbol **synth_symbol_table; 659 long i; 660 661 make_cleanup (xfree, synthsyms); 662 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount); 663 for (i = 0; i < synthcount; i++) 664 synth_symbol_table[i] = synthsyms + i; 665 make_cleanup (xfree, synth_symbol_table); 666 elf_symtab_read (objfile, ST_SYNTHETIC, synthcount, synth_symbol_table); 667 } 668 669 /* Install any minimal symbols that have been collected as the current 670 minimal symbols for this objfile. The debug readers below this point 671 should not generate new minimal symbols; if they do it's their 672 responsibility to install them. "mdebug" appears to be the only one 673 which will do this. */ 674 675 install_minimal_symbols (objfile); 676 do_cleanups (back_to); 677 678 /* Now process debugging information, which is contained in 679 special ELF sections. */ 680 681 /* If we are reinitializing, or if we have never loaded syms yet, 682 set table to empty. MAINLINE is cleared so that *_read_psymtab 683 functions do not all also re-initialize the psymbol table. */ 684 if (mainline) 685 { 686 init_psymbol_list (objfile, 0); 687 mainline = 0; 688 } 689 690 /* We first have to find them... */ 691 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei); 692 693 /* ELF debugging information is inserted into the psymtab in the 694 order of least informative first - most informative last. Since 695 the psymtab table is searched `most recent insertion first' this 696 increases the probability that more detailed debug information 697 for a section is found. 698 699 For instance, an object file might contain both .mdebug (XCOFF) 700 and .debug_info (DWARF2) sections then .mdebug is inserted first 701 (searched last) and DWARF2 is inserted last (searched first). If 702 we don't do this then the XCOFF info is found first - for code in 703 an included file XCOFF info is useless. */ 704 705 if (ei.mdebugsect) 706 { 707 const struct ecoff_debug_swap *swap; 708 709 /* .mdebug section, presumably holding ECOFF debugging 710 information. */ 711 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; 712 if (swap) 713 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect); 714 } 715 if (ei.stabsect) 716 { 717 asection *str_sect; 718 719 /* Stab sections have an associated string table that looks like 720 a separate section. */ 721 str_sect = bfd_get_section_by_name (abfd, ".stabstr"); 722 723 /* FIXME should probably warn about a stab section without a stabstr. */ 724 if (str_sect) 725 elfstab_build_psymtabs (objfile, 726 mainline, 727 ei.stabsect, 728 str_sect->filepos, 729 bfd_section_size (abfd, str_sect)); 730 } 731 if (dwarf2_has_info (objfile)) 732 { 733 /* DWARF 2 sections */ 734 dwarf2_build_psymtabs (objfile, mainline); 735 } 736 737 /* FIXME: kettenis/20030504: This still needs to be integrated with 738 dwarf2read.c in a better way. */ 739 dwarf2_build_frame_info (objfile); 740 } 741 742 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and 743 the chain of stab_section_info's, that might be dangling from 744 it. */ 745 746 static void 747 free_elfinfo (void *objp) 748 { 749 struct objfile *objfile = (struct objfile *) objp; 750 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info; 751 struct stab_section_info *ssi, *nssi; 752 753 ssi = dbxinfo->stab_section_info; 754 while (ssi) 755 { 756 nssi = ssi->next; 757 xfree (ssi); 758 ssi = nssi; 759 } 760 761 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ 762 } 763 764 765 /* Initialize anything that needs initializing when a completely new symbol 766 file is specified (not just adding some symbols from another file, e.g. a 767 shared library). 768 769 We reinitialize buildsym, since we may be reading stabs from an ELF file. */ 770 771 static void 772 elf_new_init (struct objfile *ignore) 773 { 774 stabsread_new_init (); 775 buildsym_new_init (); 776 } 777 778 /* Perform any local cleanups required when we are done with a particular 779 objfile. I.E, we are in the process of discarding all symbol information 780 for an objfile, freeing up all memory held for it, and unlinking the 781 objfile struct from the global list of known objfiles. */ 782 783 static void 784 elf_symfile_finish (struct objfile *objfile) 785 { 786 if (objfile->deprecated_sym_stab_info != NULL) 787 { 788 xfree (objfile->deprecated_sym_stab_info); 789 } 790 791 dwarf2_free_objfile (objfile); 792 } 793 794 /* ELF specific initialization routine for reading symbols. 795 796 It is passed a pointer to a struct sym_fns which contains, among other 797 things, the BFD for the file whose symbols are being read, and a slot for 798 a pointer to "private data" which we can fill with goodies. 799 800 For now at least, we have nothing in particular to do, so this function is 801 just a stub. */ 802 803 static void 804 elf_symfile_init (struct objfile *objfile) 805 { 806 /* ELF objects may be reordered, so set OBJF_REORDERED. If we 807 find this causes a significant slowdown in gdb then we could 808 set it in the debug symbol readers only when necessary. */ 809 objfile->flags |= OBJF_REORDERED; 810 } 811 812 /* When handling an ELF file that contains Sun STABS debug info, 813 some of the debug info is relative to the particular chunk of the 814 section that was generated in its individual .o file. E.g. 815 offsets to static variables are relative to the start of the data 816 segment *for that module before linking*. This information is 817 painfully squirreled away in the ELF symbol table as local symbols 818 with wierd names. Go get 'em when needed. */ 819 820 void 821 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst) 822 { 823 char *filename = pst->filename; 824 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; 825 struct stab_section_info *maybe = dbx->stab_section_info; 826 struct stab_section_info *questionable = 0; 827 int i; 828 char *p; 829 830 /* The ELF symbol info doesn't include path names, so strip the path 831 (if any) from the psymtab filename. */ 832 while (0 != (p = strchr (filename, '/'))) 833 filename = p + 1; 834 835 /* FIXME: This linear search could speed up significantly 836 if it was chained in the right order to match how we search it, 837 and if we unchained when we found a match. */ 838 for (; maybe; maybe = maybe->next) 839 { 840 if (filename[0] == maybe->filename[0] 841 && strcmp (filename, maybe->filename) == 0) 842 { 843 /* We found a match. But there might be several source files 844 (from different directories) with the same name. */ 845 if (0 == maybe->found) 846 break; 847 questionable = maybe; /* Might use it later. */ 848 } 849 } 850 851 if (maybe == 0 && questionable != 0) 852 { 853 complaint (&symfile_complaints, 854 _("elf/stab section information questionable for %s"), filename); 855 maybe = questionable; 856 } 857 858 if (maybe) 859 { 860 /* Found it! Allocate a new psymtab struct, and fill it in. */ 861 maybe->found++; 862 pst->section_offsets = (struct section_offsets *) 863 obstack_alloc (&objfile->objfile_obstack, 864 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections)); 865 for (i = 0; i < maybe->num_sections; i++) 866 (pst->section_offsets)->offsets[i] = maybe->sections[i]; 867 return; 868 } 869 870 /* We were unable to find any offsets for this file. Complain. */ 871 if (dbx->stab_section_info) /* If there *is* any info, */ 872 complaint (&symfile_complaints, 873 _("elf/stab section information missing for %s"), filename); 874 } 875 876 /* Register that we are able to handle ELF object file formats. */ 877 878 static struct sym_fns elf_sym_fns = 879 { 880 bfd_target_elf_flavour, 881 elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ 882 elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ 883 elf_symfile_read, /* sym_read: read a symbol file into symtab */ 884 elf_symfile_finish, /* sym_finish: finished with file, cleanup */ 885 default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */ 886 elf_symfile_segments, /* sym_segments: Get segment information from 887 a file. */ 888 NULL, /* sym_read_linetable */ 889 NULL /* next: pointer to next struct sym_fns */ 890 }; 891 892 void 893 _initialize_elfread (void) 894 { 895 add_symtab_fns (&elf_sym_fns); 896 } 897