1 /* Read ELF (Executable and Linking Format) object files for GDB. 2 3 Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 4 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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 #include "psympriv.h" 40 #include "filenames.h" 41 #include "gdbtypes.h" 42 #include "value.h" 43 #include "infcall.h" 44 #include "gdbthread.h" 45 #include "regcache.h" 46 47 extern void _initialize_elfread (void); 48 49 /* Forward declarations. */ 50 static const struct sym_fns elf_sym_fns_gdb_index; 51 static const struct sym_fns elf_sym_fns_lazy_psyms; 52 53 /* The struct elfinfo is available only during ELF symbol table and 54 psymtab reading. It is destroyed at the completion of psymtab-reading. 55 It's local to elf_symfile_read. */ 56 57 struct elfinfo 58 { 59 asection *stabsect; /* Section pointer for .stab section */ 60 asection *stabindexsect; /* Section pointer for .stab.index section */ 61 asection *mdebugsect; /* Section pointer for .mdebug section */ 62 }; 63 64 static void free_elfinfo (void *); 65 66 /* Minimal symbols located at the GOT entries for .plt - that is the real 67 pointer where the given entry will jump to. It gets updated by the real 68 function address during lazy ld.so resolving in the inferior. These 69 minimal symbols are indexed for <tab>-completion. */ 70 71 #define SYMBOL_GOT_PLT_SUFFIX "@got.plt" 72 73 /* Locate the segments in ABFD. */ 74 75 static struct symfile_segment_data * 76 elf_symfile_segments (bfd *abfd) 77 { 78 Elf_Internal_Phdr *phdrs, **segments; 79 long phdrs_size; 80 int num_phdrs, num_segments, num_sections, i; 81 asection *sect; 82 struct symfile_segment_data *data; 83 84 phdrs_size = bfd_get_elf_phdr_upper_bound (abfd); 85 if (phdrs_size == -1) 86 return NULL; 87 88 phdrs = alloca (phdrs_size); 89 num_phdrs = bfd_get_elf_phdrs (abfd, phdrs); 90 if (num_phdrs == -1) 91 return NULL; 92 93 num_segments = 0; 94 segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs); 95 for (i = 0; i < num_phdrs; i++) 96 if (phdrs[i].p_type == PT_LOAD) 97 segments[num_segments++] = &phdrs[i]; 98 99 if (num_segments == 0) 100 return NULL; 101 102 data = XZALLOC (struct symfile_segment_data); 103 data->num_segments = num_segments; 104 data->segment_bases = XCALLOC (num_segments, CORE_ADDR); 105 data->segment_sizes = XCALLOC (num_segments, CORE_ADDR); 106 107 for (i = 0; i < num_segments; i++) 108 { 109 data->segment_bases[i] = segments[i]->p_vaddr; 110 data->segment_sizes[i] = segments[i]->p_memsz; 111 } 112 113 num_sections = bfd_count_sections (abfd); 114 data->segment_info = XCALLOC (num_sections, int); 115 116 for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next) 117 { 118 int j; 119 CORE_ADDR vma; 120 121 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) 122 continue; 123 124 vma = bfd_get_section_vma (abfd, sect); 125 126 for (j = 0; j < num_segments; j++) 127 if (segments[j]->p_memsz > 0 128 && vma >= segments[j]->p_vaddr 129 && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz) 130 { 131 data->segment_info[i] = j + 1; 132 break; 133 } 134 135 /* We should have found a segment for every non-empty section. 136 If we haven't, we will not relocate this section by any 137 offsets we apply to the segments. As an exception, do not 138 warn about SHT_NOBITS sections; in normal ELF execution 139 environments, SHT_NOBITS means zero-initialized and belongs 140 in a segment, but in no-OS environments some tools (e.g. ARM 141 RealView) use SHT_NOBITS for uninitialized data. Since it is 142 uninitialized, it doesn't need a program header. Such 143 binaries are not relocatable. */ 144 if (bfd_get_section_size (sect) > 0 && j == num_segments 145 && (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0) 146 warning (_("Loadable segment \"%s\" outside of ELF segments"), 147 bfd_section_name (abfd, sect)); 148 } 149 150 return data; 151 } 152 153 /* We are called once per section from elf_symfile_read. We 154 need to examine each section we are passed, check to see 155 if it is something we are interested in processing, and 156 if so, stash away some access information for the section. 157 158 For now we recognize the dwarf debug information sections and 159 line number sections from matching their section names. The 160 ELF definition is no real help here since it has no direct 161 knowledge of DWARF (by design, so any debugging format can be 162 used). 163 164 We also recognize the ".stab" sections used by the Sun compilers 165 released with Solaris 2. 166 167 FIXME: The section names should not be hardwired strings (what 168 should they be? I don't think most object file formats have enough 169 section flags to specify what kind of debug section it is. 170 -kingdon). */ 171 172 static void 173 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip) 174 { 175 struct elfinfo *ei; 176 177 ei = (struct elfinfo *) eip; 178 if (strcmp (sectp->name, ".stab") == 0) 179 { 180 ei->stabsect = sectp; 181 } 182 else if (strcmp (sectp->name, ".stab.index") == 0) 183 { 184 ei->stabindexsect = sectp; 185 } 186 else if (strcmp (sectp->name, ".mdebug") == 0) 187 { 188 ei->mdebugsect = sectp; 189 } 190 } 191 192 static struct minimal_symbol * 193 record_minimal_symbol (const char *name, int name_len, int copy_name, 194 CORE_ADDR address, 195 enum minimal_symbol_type ms_type, 196 asection *bfd_section, struct objfile *objfile) 197 { 198 struct gdbarch *gdbarch = get_objfile_arch (objfile); 199 200 if (ms_type == mst_text || ms_type == mst_file_text 201 || ms_type == mst_text_gnu_ifunc) 202 address = gdbarch_smash_text_address (gdbarch, address); 203 204 return prim_record_minimal_symbol_full (name, name_len, copy_name, address, 205 ms_type, bfd_section->index, 206 bfd_section, objfile); 207 } 208 209 /* 210 211 LOCAL FUNCTION 212 213 elf_symtab_read -- read the symbol table of an ELF file 214 215 SYNOPSIS 216 217 void elf_symtab_read (struct objfile *objfile, int type, 218 long number_of_symbols, asymbol **symbol_table) 219 220 DESCRIPTION 221 222 Given an objfile, a symbol table, and a flag indicating whether the 223 symbol table contains regular, dynamic, or synthetic symbols, add all 224 the global function and data symbols to the minimal symbol table. 225 226 In stabs-in-ELF, as implemented by Sun, there are some local symbols 227 defined in the ELF symbol table, which can be used to locate 228 the beginnings of sections from each ".o" file that was linked to 229 form the executable objfile. We gather any such info and record it 230 in data structures hung off the objfile's private data. 231 232 */ 233 234 #define ST_REGULAR 0 235 #define ST_DYNAMIC 1 236 #define ST_SYNTHETIC 2 237 238 static void 239 elf_symtab_read (struct objfile *objfile, int type, 240 long number_of_symbols, asymbol **symbol_table, 241 int copy_names) 242 { 243 struct gdbarch *gdbarch = get_objfile_arch (objfile); 244 asymbol *sym; 245 long i; 246 CORE_ADDR symaddr; 247 CORE_ADDR offset; 248 enum minimal_symbol_type ms_type; 249 /* If sectinfo is nonNULL, it contains section info that should end up 250 filed in the objfile. */ 251 struct stab_section_info *sectinfo = NULL; 252 /* If filesym is nonzero, it points to a file symbol, but we haven't 253 seen any section info for it yet. */ 254 asymbol *filesym = 0; 255 /* Name of filesym. This is either a constant string or is saved on 256 the objfile's obstack. */ 257 char *filesymname = ""; 258 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; 259 int stripped = (bfd_get_symcount (objfile->obfd) == 0); 260 261 for (i = 0; i < number_of_symbols; i++) 262 { 263 sym = symbol_table[i]; 264 if (sym->name == NULL || *sym->name == '\0') 265 { 266 /* Skip names that don't exist (shouldn't happen), or names 267 that are null strings (may happen). */ 268 continue; 269 } 270 271 /* Skip "special" symbols, e.g. ARM mapping symbols. These are 272 symbols which do not correspond to objects in the symbol table, 273 but have some other target-specific meaning. */ 274 if (bfd_is_target_special_symbol (objfile->obfd, sym)) 275 { 276 if (gdbarch_record_special_symbol_p (gdbarch)) 277 gdbarch_record_special_symbol (gdbarch, objfile, sym); 278 continue; 279 } 280 281 offset = ANOFFSET (objfile->section_offsets, sym->section->index); 282 if (type == ST_DYNAMIC 283 && sym->section == &bfd_und_section 284 && (sym->flags & BSF_FUNCTION)) 285 { 286 struct minimal_symbol *msym; 287 bfd *abfd = objfile->obfd; 288 asection *sect; 289 290 /* Symbol is a reference to a function defined in 291 a shared library. 292 If its value is non zero then it is usually the address 293 of the corresponding entry in the procedure linkage table, 294 plus the desired section offset. 295 If its value is zero then the dynamic linker has to resolve 296 the symbol. We are unable to find any meaningful address 297 for this symbol in the executable file, so we skip it. */ 298 symaddr = sym->value; 299 if (symaddr == 0) 300 continue; 301 302 /* sym->section is the undefined section. However, we want to 303 record the section where the PLT stub resides with the 304 minimal symbol. Search the section table for the one that 305 covers the stub's address. */ 306 for (sect = abfd->sections; sect != NULL; sect = sect->next) 307 { 308 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) 309 continue; 310 311 if (symaddr >= bfd_get_section_vma (abfd, sect) 312 && symaddr < bfd_get_section_vma (abfd, sect) 313 + bfd_get_section_size (sect)) 314 break; 315 } 316 if (!sect) 317 continue; 318 319 symaddr += ANOFFSET (objfile->section_offsets, sect->index); 320 321 msym = record_minimal_symbol 322 (sym->name, strlen (sym->name), copy_names, 323 symaddr, mst_solib_trampoline, sect, objfile); 324 if (msym != NULL) 325 msym->filename = filesymname; 326 continue; 327 } 328 329 /* If it is a nonstripped executable, do not enter dynamic 330 symbols, as the dynamic symbol table is usually a subset 331 of the main symbol table. */ 332 if (type == ST_DYNAMIC && !stripped) 333 continue; 334 if (sym->flags & BSF_FILE) 335 { 336 /* STT_FILE debugging symbol that helps stabs-in-elf debugging. 337 Chain any old one onto the objfile; remember new sym. */ 338 if (sectinfo != NULL) 339 { 340 sectinfo->next = dbx->stab_section_info; 341 dbx->stab_section_info = sectinfo; 342 sectinfo = NULL; 343 } 344 filesym = sym; 345 filesymname = 346 obsavestring ((char *) filesym->name, strlen (filesym->name), 347 &objfile->objfile_obstack); 348 } 349 else if (sym->flags & BSF_SECTION_SYM) 350 continue; 351 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) 352 { 353 struct minimal_symbol *msym; 354 355 /* Select global/local/weak symbols. Note that bfd puts abs 356 symbols in their own section, so all symbols we are 357 interested in will have a section. */ 358 /* Bfd symbols are section relative. */ 359 symaddr = sym->value + sym->section->vma; 360 /* Relocate all non-absolute and non-TLS symbols by the 361 section offset. */ 362 if (sym->section != &bfd_abs_section 363 && !(sym->section->flags & SEC_THREAD_LOCAL)) 364 { 365 symaddr += offset; 366 } 367 /* For non-absolute symbols, use the type of the section 368 they are relative to, to intuit text/data. Bfd provides 369 no way of figuring this out for absolute symbols. */ 370 if (sym->section == &bfd_abs_section) 371 { 372 /* This is a hack to get the minimal symbol type 373 right for Irix 5, which has absolute addresses 374 with special section indices for dynamic symbols. 375 376 NOTE: uweigand-20071112: Synthetic symbols do not 377 have an ELF-private part, so do not touch those. */ 378 unsigned int shndx = type == ST_SYNTHETIC ? 0 : 379 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; 380 381 switch (shndx) 382 { 383 case SHN_MIPS_TEXT: 384 ms_type = mst_text; 385 break; 386 case SHN_MIPS_DATA: 387 ms_type = mst_data; 388 break; 389 case SHN_MIPS_ACOMMON: 390 ms_type = mst_bss; 391 break; 392 default: 393 ms_type = mst_abs; 394 } 395 396 /* If it is an Irix dynamic symbol, skip section name 397 symbols, relocate all others by section offset. */ 398 if (ms_type != mst_abs) 399 { 400 if (sym->name[0] == '.') 401 continue; 402 symaddr += offset; 403 } 404 } 405 else if (sym->section->flags & SEC_CODE) 406 { 407 if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) 408 { 409 if (sym->flags & BSF_GNU_INDIRECT_FUNCTION) 410 ms_type = mst_text_gnu_ifunc; 411 else 412 ms_type = mst_text; 413 } 414 else if ((sym->name[0] == '.' && sym->name[1] == 'L') 415 || ((sym->flags & BSF_LOCAL) 416 && sym->name[0] == '$' 417 && sym->name[1] == 'L')) 418 /* Looks like a compiler-generated label. Skip 419 it. The assembler should be skipping these (to 420 keep executables small), but apparently with 421 gcc on the (deleted) delta m88k SVR4, it loses. 422 So to have us check too should be harmless (but 423 I encourage people to fix this in the assembler 424 instead of adding checks here). */ 425 continue; 426 else 427 { 428 ms_type = mst_file_text; 429 } 430 } 431 else if (sym->section->flags & SEC_ALLOC) 432 { 433 if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) 434 { 435 if (sym->section->flags & SEC_LOAD) 436 { 437 ms_type = mst_data; 438 } 439 else 440 { 441 ms_type = mst_bss; 442 } 443 } 444 else if (sym->flags & BSF_LOCAL) 445 { 446 /* Named Local variable in a Data section. 447 Check its name for stabs-in-elf. */ 448 int special_local_sect; 449 450 if (strcmp ("Bbss.bss", sym->name) == 0) 451 special_local_sect = SECT_OFF_BSS (objfile); 452 else if (strcmp ("Ddata.data", sym->name) == 0) 453 special_local_sect = SECT_OFF_DATA (objfile); 454 else if (strcmp ("Drodata.rodata", sym->name) == 0) 455 special_local_sect = SECT_OFF_RODATA (objfile); 456 else 457 special_local_sect = -1; 458 if (special_local_sect >= 0) 459 { 460 /* Found a special local symbol. Allocate a 461 sectinfo, if needed, and fill it in. */ 462 if (sectinfo == NULL) 463 { 464 int max_index; 465 size_t size; 466 467 max_index = SECT_OFF_BSS (objfile); 468 if (objfile->sect_index_data > max_index) 469 max_index = objfile->sect_index_data; 470 if (objfile->sect_index_rodata > max_index) 471 max_index = objfile->sect_index_rodata; 472 473 /* max_index is the largest index we'll 474 use into this array, so we must 475 allocate max_index+1 elements for it. 476 However, 'struct stab_section_info' 477 already includes one element, so we 478 need to allocate max_index aadditional 479 elements. */ 480 size = (sizeof (struct stab_section_info) 481 + (sizeof (CORE_ADDR) * max_index)); 482 sectinfo = (struct stab_section_info *) 483 xmalloc (size); 484 memset (sectinfo, 0, size); 485 sectinfo->num_sections = max_index; 486 if (filesym == NULL) 487 { 488 complaint (&symfile_complaints, 489 _("elf/stab section information %s " 490 "without a preceding file symbol"), 491 sym->name); 492 } 493 else 494 { 495 sectinfo->filename = 496 (char *) filesym->name; 497 } 498 } 499 if (sectinfo->sections[special_local_sect] != 0) 500 complaint (&symfile_complaints, 501 _("duplicated elf/stab section " 502 "information for %s"), 503 sectinfo->filename); 504 /* BFD symbols are section relative. */ 505 symaddr = sym->value + sym->section->vma; 506 /* Relocate non-absolute symbols by the 507 section offset. */ 508 if (sym->section != &bfd_abs_section) 509 symaddr += offset; 510 sectinfo->sections[special_local_sect] = symaddr; 511 /* The special local symbols don't go in the 512 minimal symbol table, so ignore this one. */ 513 continue; 514 } 515 /* Not a special stabs-in-elf symbol, do regular 516 symbol processing. */ 517 if (sym->section->flags & SEC_LOAD) 518 { 519 ms_type = mst_file_data; 520 } 521 else 522 { 523 ms_type = mst_file_bss; 524 } 525 } 526 else 527 { 528 ms_type = mst_unknown; 529 } 530 } 531 else 532 { 533 /* FIXME: Solaris2 shared libraries include lots of 534 odd "absolute" and "undefined" symbols, that play 535 hob with actions like finding what function the PC 536 is in. Ignore them if they aren't text, data, or bss. */ 537 /* ms_type = mst_unknown; */ 538 continue; /* Skip this symbol. */ 539 } 540 msym = record_minimal_symbol 541 (sym->name, strlen (sym->name), copy_names, symaddr, 542 ms_type, sym->section, objfile); 543 544 if (msym) 545 { 546 /* Pass symbol size field in via BFD. FIXME!!! */ 547 elf_symbol_type *elf_sym; 548 549 /* NOTE: uweigand-20071112: A synthetic symbol does not have an 550 ELF-private part. However, in some cases (e.g. synthetic 551 'dot' symbols on ppc64) the udata.p entry is set to point back 552 to the original ELF symbol it was derived from. Get the size 553 from that symbol. */ 554 if (type != ST_SYNTHETIC) 555 elf_sym = (elf_symbol_type *) sym; 556 else 557 elf_sym = (elf_symbol_type *) sym->udata.p; 558 559 if (elf_sym) 560 MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size; 561 562 msym->filename = filesymname; 563 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym); 564 } 565 566 /* For @plt symbols, also record a trampoline to the 567 destination symbol. The @plt symbol will be used in 568 disassembly, and the trampoline will be used when we are 569 trying to find the target. */ 570 if (msym && ms_type == mst_text && type == ST_SYNTHETIC) 571 { 572 int len = strlen (sym->name); 573 574 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0) 575 { 576 struct minimal_symbol *mtramp; 577 578 mtramp = record_minimal_symbol (sym->name, len - 4, 1, 579 symaddr, 580 mst_solib_trampoline, 581 sym->section, objfile); 582 if (mtramp) 583 { 584 MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym); 585 mtramp->filename = filesymname; 586 gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp); 587 } 588 } 589 } 590 } 591 } 592 } 593 594 /* Build minimal symbols named `function@got.plt' (see SYMBOL_GOT_PLT_SUFFIX) 595 for later look ups of which function to call when user requests 596 a STT_GNU_IFUNC function. As the STT_GNU_IFUNC type is found at the target 597 library defining `function' we cannot yet know while reading OBJFILE which 598 of the SYMBOL_GOT_PLT_SUFFIX entries will be needed and later 599 DYN_SYMBOL_TABLE is no longer easily available for OBJFILE. */ 600 601 static void 602 elf_rel_plt_read (struct objfile *objfile, asymbol **dyn_symbol_table) 603 { 604 bfd *obfd = objfile->obfd; 605 const struct elf_backend_data *bed = get_elf_backend_data (obfd); 606 asection *plt, *relplt, *got_plt; 607 unsigned u; 608 int plt_elf_idx; 609 bfd_size_type reloc_count, reloc; 610 char *string_buffer = NULL; 611 size_t string_buffer_size = 0; 612 struct cleanup *back_to; 613 struct gdbarch *gdbarch = objfile->gdbarch; 614 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr; 615 size_t ptr_size = TYPE_LENGTH (ptr_type); 616 617 if (objfile->separate_debug_objfile_backlink) 618 return; 619 620 plt = bfd_get_section_by_name (obfd, ".plt"); 621 if (plt == NULL) 622 return; 623 plt_elf_idx = elf_section_data (plt)->this_idx; 624 625 got_plt = bfd_get_section_by_name (obfd, ".got.plt"); 626 if (got_plt == NULL) 627 return; 628 629 /* This search algorithm is from _bfd_elf_canonicalize_dynamic_reloc. */ 630 for (relplt = obfd->sections; relplt != NULL; relplt = relplt->next) 631 if (elf_section_data (relplt)->this_hdr.sh_info == plt_elf_idx 632 && (elf_section_data (relplt)->this_hdr.sh_type == SHT_REL 633 || elf_section_data (relplt)->this_hdr.sh_type == SHT_RELA)) 634 break; 635 if (relplt == NULL) 636 return; 637 638 if (! bed->s->slurp_reloc_table (obfd, relplt, dyn_symbol_table, TRUE)) 639 return; 640 641 back_to = make_cleanup (free_current_contents, &string_buffer); 642 643 reloc_count = relplt->size / elf_section_data (relplt)->this_hdr.sh_entsize; 644 for (reloc = 0; reloc < reloc_count; reloc++) 645 { 646 const char *name, *name_got_plt; 647 struct minimal_symbol *msym; 648 CORE_ADDR address; 649 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX); 650 size_t name_len; 651 652 name = bfd_asymbol_name (*relplt->relocation[reloc].sym_ptr_ptr); 653 name_len = strlen (name); 654 address = relplt->relocation[reloc].address; 655 656 /* Does the pointer reside in the .got.plt section? */ 657 if (!(bfd_get_section_vma (obfd, got_plt) <= address 658 && address < bfd_get_section_vma (obfd, got_plt) 659 + bfd_get_section_size (got_plt))) 660 continue; 661 662 /* We cannot check if NAME is a reference to mst_text_gnu_ifunc as in 663 OBJFILE the symbol is undefined and the objfile having NAME defined 664 may not yet have been loaded. */ 665 666 if (string_buffer_size < name_len + got_suffix_len) 667 { 668 string_buffer_size = 2 * (name_len + got_suffix_len); 669 string_buffer = xrealloc (string_buffer, string_buffer_size); 670 } 671 memcpy (string_buffer, name, name_len); 672 memcpy (&string_buffer[name_len], SYMBOL_GOT_PLT_SUFFIX, 673 got_suffix_len); 674 675 msym = record_minimal_symbol (string_buffer, name_len + got_suffix_len, 676 1, address, mst_slot_got_plt, got_plt, 677 objfile); 678 if (msym) 679 MSYMBOL_SIZE (msym) = ptr_size; 680 } 681 682 do_cleanups (back_to); 683 } 684 685 /* The data pointer is htab_t for gnu_ifunc_record_cache_unchecked. */ 686 687 static const struct objfile_data *elf_objfile_gnu_ifunc_cache_data; 688 689 /* Map function names to CORE_ADDR in elf_objfile_gnu_ifunc_cache_data. */ 690 691 struct elf_gnu_ifunc_cache 692 { 693 /* This is always a function entry address, not a function descriptor. */ 694 CORE_ADDR addr; 695 696 char name[1]; 697 }; 698 699 /* htab_hash for elf_objfile_gnu_ifunc_cache_data. */ 700 701 static hashval_t 702 elf_gnu_ifunc_cache_hash (const void *a_voidp) 703 { 704 const struct elf_gnu_ifunc_cache *a = a_voidp; 705 706 return htab_hash_string (a->name); 707 } 708 709 /* htab_eq for elf_objfile_gnu_ifunc_cache_data. */ 710 711 static int 712 elf_gnu_ifunc_cache_eq (const void *a_voidp, const void *b_voidp) 713 { 714 const struct elf_gnu_ifunc_cache *a = a_voidp; 715 const struct elf_gnu_ifunc_cache *b = b_voidp; 716 717 return strcmp (a->name, b->name) == 0; 718 } 719 720 /* Record the target function address of a STT_GNU_IFUNC function NAME is the 721 function entry address ADDR. Return 1 if NAME and ADDR are considered as 722 valid and therefore they were successfully recorded, return 0 otherwise. 723 724 Function does not expect a duplicate entry. Use 725 elf_gnu_ifunc_resolve_by_cache first to check if the entry for NAME already 726 exists. */ 727 728 static int 729 elf_gnu_ifunc_record_cache (const char *name, CORE_ADDR addr) 730 { 731 struct minimal_symbol *msym; 732 asection *sect; 733 struct objfile *objfile; 734 htab_t htab; 735 struct elf_gnu_ifunc_cache entry_local, *entry_p; 736 void **slot; 737 738 msym = lookup_minimal_symbol_by_pc (addr); 739 if (msym == NULL) 740 return 0; 741 if (SYMBOL_VALUE_ADDRESS (msym) != addr) 742 return 0; 743 /* minimal symbols have always SYMBOL_OBJ_SECTION non-NULL. */ 744 sect = SYMBOL_OBJ_SECTION (msym)->the_bfd_section; 745 objfile = SYMBOL_OBJ_SECTION (msym)->objfile; 746 747 /* If .plt jumps back to .plt the symbol is still deferred for later 748 resolution and it has no use for GDB. Besides ".text" this symbol can 749 reside also in ".opd" for ppc64 function descriptor. */ 750 if (strcmp (bfd_get_section_name (objfile->obfd, sect), ".plt") == 0) 751 return 0; 752 753 htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data); 754 if (htab == NULL) 755 { 756 htab = htab_create_alloc_ex (1, elf_gnu_ifunc_cache_hash, 757 elf_gnu_ifunc_cache_eq, 758 NULL, &objfile->objfile_obstack, 759 hashtab_obstack_allocate, 760 dummy_obstack_deallocate); 761 set_objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data, htab); 762 } 763 764 entry_local.addr = addr; 765 obstack_grow (&objfile->objfile_obstack, &entry_local, 766 offsetof (struct elf_gnu_ifunc_cache, name)); 767 obstack_grow_str0 (&objfile->objfile_obstack, name); 768 entry_p = obstack_finish (&objfile->objfile_obstack); 769 770 slot = htab_find_slot (htab, entry_p, INSERT); 771 if (*slot != NULL) 772 { 773 struct elf_gnu_ifunc_cache *entry_found_p = *slot; 774 struct gdbarch *gdbarch = objfile->gdbarch; 775 776 if (entry_found_p->addr != addr) 777 { 778 /* This case indicates buggy inferior program, the resolved address 779 should never change. */ 780 781 warning (_("gnu-indirect-function \"%s\" has changed its resolved " 782 "function_address from %s to %s"), 783 name, paddress (gdbarch, entry_found_p->addr), 784 paddress (gdbarch, addr)); 785 } 786 787 /* New ENTRY_P is here leaked/duplicate in the OBJFILE obstack. */ 788 } 789 *slot = entry_p; 790 791 return 1; 792 } 793 794 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC 795 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P 796 is not NULL) and the function returns 1. It returns 0 otherwise. 797 798 Only the elf_objfile_gnu_ifunc_cache_data hash table is searched by this 799 function. */ 800 801 static int 802 elf_gnu_ifunc_resolve_by_cache (const char *name, CORE_ADDR *addr_p) 803 { 804 struct objfile *objfile; 805 806 ALL_PSPACE_OBJFILES (current_program_space, objfile) 807 { 808 htab_t htab; 809 struct elf_gnu_ifunc_cache *entry_p; 810 void **slot; 811 812 htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data); 813 if (htab == NULL) 814 continue; 815 816 entry_p = alloca (sizeof (*entry_p) + strlen (name)); 817 strcpy (entry_p->name, name); 818 819 slot = htab_find_slot (htab, entry_p, NO_INSERT); 820 if (slot == NULL) 821 continue; 822 entry_p = *slot; 823 gdb_assert (entry_p != NULL); 824 825 if (addr_p) 826 *addr_p = entry_p->addr; 827 return 1; 828 } 829 830 return 0; 831 } 832 833 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC 834 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P 835 is not NULL) and the function returns 1. It returns 0 otherwise. 836 837 Only the SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. 838 elf_gnu_ifunc_resolve_by_cache must have been already called for NAME to 839 prevent cache entries duplicates. */ 840 841 static int 842 elf_gnu_ifunc_resolve_by_got (const char *name, CORE_ADDR *addr_p) 843 { 844 char *name_got_plt; 845 struct objfile *objfile; 846 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX); 847 848 name_got_plt = alloca (strlen (name) + got_suffix_len + 1); 849 sprintf (name_got_plt, "%s" SYMBOL_GOT_PLT_SUFFIX, name); 850 851 ALL_PSPACE_OBJFILES (current_program_space, objfile) 852 { 853 bfd *obfd = objfile->obfd; 854 struct gdbarch *gdbarch = objfile->gdbarch; 855 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr; 856 size_t ptr_size = TYPE_LENGTH (ptr_type); 857 CORE_ADDR pointer_address, addr; 858 asection *plt; 859 gdb_byte *buf = alloca (ptr_size); 860 struct minimal_symbol *msym; 861 862 msym = lookup_minimal_symbol (name_got_plt, NULL, objfile); 863 if (msym == NULL) 864 continue; 865 if (MSYMBOL_TYPE (msym) != mst_slot_got_plt) 866 continue; 867 pointer_address = SYMBOL_VALUE_ADDRESS (msym); 868 869 plt = bfd_get_section_by_name (obfd, ".plt"); 870 if (plt == NULL) 871 continue; 872 873 if (MSYMBOL_SIZE (msym) != ptr_size) 874 continue; 875 if (target_read_memory (pointer_address, buf, ptr_size) != 0) 876 continue; 877 addr = extract_typed_address (buf, ptr_type); 878 addr = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, 879 ¤t_target); 880 881 if (addr_p) 882 *addr_p = addr; 883 if (elf_gnu_ifunc_record_cache (name, addr)) 884 return 1; 885 } 886 887 return 0; 888 } 889 890 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC 891 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P 892 is not NULL) and the function returns 1. It returns 0 otherwise. 893 894 Both the elf_objfile_gnu_ifunc_cache_data hash table and 895 SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. */ 896 897 static int 898 elf_gnu_ifunc_resolve_name (const char *name, CORE_ADDR *addr_p) 899 { 900 if (elf_gnu_ifunc_resolve_by_cache (name, addr_p)) 901 return 1; 902 903 if (elf_gnu_ifunc_resolve_by_got (name, addr_p)) 904 return 1; 905 906 return 0; 907 } 908 909 /* Call STT_GNU_IFUNC - a function returning addresss of a real function to 910 call. PC is theSTT_GNU_IFUNC resolving function entry. The value returned 911 is the entry point of the resolved STT_GNU_IFUNC target function to call. 912 */ 913 914 static CORE_ADDR 915 elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc) 916 { 917 char *name_at_pc; 918 CORE_ADDR start_at_pc, address; 919 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func; 920 struct value *function, *address_val; 921 922 /* Try first any non-intrusive methods without an inferior call. */ 923 924 if (find_pc_partial_function (pc, &name_at_pc, &start_at_pc, NULL) 925 && start_at_pc == pc) 926 { 927 if (elf_gnu_ifunc_resolve_name (name_at_pc, &address)) 928 return address; 929 } 930 else 931 name_at_pc = NULL; 932 933 function = allocate_value (func_func_type); 934 set_value_address (function, pc); 935 936 /* STT_GNU_IFUNC resolver functions have no parameters. FUNCTION is the 937 function entry address. ADDRESS may be a function descriptor. */ 938 939 address_val = call_function_by_hand (function, 0, NULL); 940 address = value_as_address (address_val); 941 address = gdbarch_convert_from_func_ptr_addr (gdbarch, address, 942 ¤t_target); 943 944 if (name_at_pc) 945 elf_gnu_ifunc_record_cache (name_at_pc, address); 946 947 return address; 948 } 949 950 /* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition. */ 951 952 static void 953 elf_gnu_ifunc_resolver_stop (struct breakpoint *b) 954 { 955 struct breakpoint *b_return; 956 struct frame_info *prev_frame = get_prev_frame (get_current_frame ()); 957 struct frame_id prev_frame_id = get_stack_frame_id (prev_frame); 958 CORE_ADDR prev_pc = get_frame_pc (prev_frame); 959 int thread_id = pid_to_thread_id (inferior_ptid); 960 961 gdb_assert (b->type == bp_gnu_ifunc_resolver); 962 963 for (b_return = b->related_breakpoint; b_return != b; 964 b_return = b_return->related_breakpoint) 965 { 966 gdb_assert (b_return->type == bp_gnu_ifunc_resolver_return); 967 gdb_assert (b_return->loc != NULL && b_return->loc->next == NULL); 968 gdb_assert (frame_id_p (b_return->frame_id)); 969 970 if (b_return->thread == thread_id 971 && b_return->loc->requested_address == prev_pc 972 && frame_id_eq (b_return->frame_id, prev_frame_id)) 973 break; 974 } 975 976 if (b_return == b) 977 { 978 struct symtab_and_line sal; 979 980 /* No need to call find_pc_line for symbols resolving as this is only 981 a helper breakpointer never shown to the user. */ 982 983 init_sal (&sal); 984 sal.pspace = current_inferior ()->pspace; 985 sal.pc = prev_pc; 986 sal.section = find_pc_overlay (sal.pc); 987 sal.explicit_pc = 1; 988 b_return = set_momentary_breakpoint (get_frame_arch (prev_frame), sal, 989 prev_frame_id, 990 bp_gnu_ifunc_resolver_return); 991 992 /* Add new b_return to the ring list b->related_breakpoint. */ 993 gdb_assert (b_return->related_breakpoint == b_return); 994 b_return->related_breakpoint = b->related_breakpoint; 995 b->related_breakpoint = b_return; 996 } 997 } 998 999 /* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition. */ 1000 1001 static void 1002 elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b) 1003 { 1004 struct gdbarch *gdbarch = get_frame_arch (get_current_frame ()); 1005 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func; 1006 struct type *value_type = TYPE_TARGET_TYPE (func_func_type); 1007 struct regcache *regcache = get_thread_regcache (inferior_ptid); 1008 struct value *value; 1009 CORE_ADDR resolved_address, resolved_pc; 1010 struct symtab_and_line sal; 1011 struct symtabs_and_lines sals, sals_end; 1012 1013 gdb_assert (b->type == bp_gnu_ifunc_resolver_return); 1014 1015 value = allocate_value (value_type); 1016 gdbarch_return_value (gdbarch, func_func_type, value_type, regcache, 1017 value_contents_raw (value), NULL); 1018 resolved_address = value_as_address (value); 1019 resolved_pc = gdbarch_convert_from_func_ptr_addr (gdbarch, 1020 resolved_address, 1021 ¤t_target); 1022 1023 while (b->related_breakpoint != b) 1024 { 1025 struct breakpoint *b_next = b->related_breakpoint; 1026 1027 switch (b->type) 1028 { 1029 case bp_gnu_ifunc_resolver: 1030 break; 1031 case bp_gnu_ifunc_resolver_return: 1032 delete_breakpoint (b); 1033 break; 1034 default: 1035 internal_error (__FILE__, __LINE__, 1036 _("handle_inferior_event: Invalid " 1037 "gnu-indirect-function breakpoint type %d"), 1038 (int) b->type); 1039 } 1040 b = b_next; 1041 } 1042 gdb_assert (b->type == bp_gnu_ifunc_resolver); 1043 1044 gdb_assert (current_program_space == b->pspace); 1045 elf_gnu_ifunc_record_cache (b->addr_string, resolved_pc); 1046 1047 sal = find_pc_line (resolved_pc, 0); 1048 sals.nelts = 1; 1049 sals.sals = &sal; 1050 sals_end.nelts = 0; 1051 1052 b->type = bp_breakpoint; 1053 update_breakpoint_locations (b, sals, sals_end); 1054 } 1055 1056 struct build_id 1057 { 1058 size_t size; 1059 gdb_byte data[1]; 1060 }; 1061 1062 /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */ 1063 1064 static struct build_id * 1065 build_id_bfd_get (bfd *abfd) 1066 { 1067 struct build_id *retval; 1068 1069 if (!bfd_check_format (abfd, bfd_object) 1070 || bfd_get_flavour (abfd) != bfd_target_elf_flavour 1071 || elf_tdata (abfd)->build_id == NULL) 1072 return NULL; 1073 1074 retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size); 1075 retval->size = elf_tdata (abfd)->build_id_size; 1076 memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size); 1077 1078 return retval; 1079 } 1080 1081 /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */ 1082 1083 static int 1084 build_id_verify (const char *filename, struct build_id *check) 1085 { 1086 bfd *abfd; 1087 struct build_id *found = NULL; 1088 int retval = 0; 1089 1090 /* We expect to be silent on the non-existing files. */ 1091 abfd = bfd_open_maybe_remote (filename); 1092 if (abfd == NULL) 1093 return 0; 1094 1095 found = build_id_bfd_get (abfd); 1096 1097 if (found == NULL) 1098 warning (_("File \"%s\" has no build-id, file skipped"), filename); 1099 else if (found->size != check->size 1100 || memcmp (found->data, check->data, found->size) != 0) 1101 warning (_("File \"%s\" has a different build-id, file skipped"), 1102 filename); 1103 else 1104 retval = 1; 1105 1106 gdb_bfd_close_or_warn (abfd); 1107 1108 xfree (found); 1109 1110 return retval; 1111 } 1112 1113 static char * 1114 build_id_to_debug_filename (struct build_id *build_id) 1115 { 1116 char *link, *debugdir, *retval = NULL; 1117 1118 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */ 1119 link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1 1120 + 2 * build_id->size + (sizeof ".debug" - 1) + 1); 1121 1122 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will 1123 cause "/.build-id/..." lookups. */ 1124 1125 debugdir = debug_file_directory; 1126 do 1127 { 1128 char *s, *debugdir_end; 1129 gdb_byte *data = build_id->data; 1130 size_t size = build_id->size; 1131 1132 while (*debugdir == DIRNAME_SEPARATOR) 1133 debugdir++; 1134 1135 debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR); 1136 if (debugdir_end == NULL) 1137 debugdir_end = &debugdir[strlen (debugdir)]; 1138 1139 memcpy (link, debugdir, debugdir_end - debugdir); 1140 s = &link[debugdir_end - debugdir]; 1141 s += sprintf (s, "/.build-id/"); 1142 if (size > 0) 1143 { 1144 size--; 1145 s += sprintf (s, "%02x", (unsigned) *data++); 1146 } 1147 if (size > 0) 1148 *s++ = '/'; 1149 while (size-- > 0) 1150 s += sprintf (s, "%02x", (unsigned) *data++); 1151 strcpy (s, ".debug"); 1152 1153 /* lrealpath() is expensive even for the usually non-existent files. */ 1154 if (access (link, F_OK) == 0) 1155 retval = lrealpath (link); 1156 1157 if (retval != NULL && !build_id_verify (retval, build_id)) 1158 { 1159 xfree (retval); 1160 retval = NULL; 1161 } 1162 1163 if (retval != NULL) 1164 break; 1165 1166 debugdir = debugdir_end; 1167 } 1168 while (*debugdir != 0); 1169 1170 return retval; 1171 } 1172 1173 static char * 1174 find_separate_debug_file_by_buildid (struct objfile *objfile) 1175 { 1176 struct build_id *build_id; 1177 1178 build_id = build_id_bfd_get (objfile->obfd); 1179 if (build_id != NULL) 1180 { 1181 char *build_id_name; 1182 1183 build_id_name = build_id_to_debug_filename (build_id); 1184 xfree (build_id); 1185 /* Prevent looping on a stripped .debug file. */ 1186 if (build_id_name != NULL 1187 && filename_cmp (build_id_name, objfile->name) == 0) 1188 { 1189 warning (_("\"%s\": separate debug info file has no debug info"), 1190 build_id_name); 1191 xfree (build_id_name); 1192 } 1193 else if (build_id_name != NULL) 1194 return build_id_name; 1195 } 1196 return NULL; 1197 } 1198 1199 /* Scan and build partial symbols for a symbol file. 1200 We have been initialized by a call to elf_symfile_init, which 1201 currently does nothing. 1202 1203 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols 1204 in each section. We simplify it down to a single offset for all 1205 symbols. FIXME. 1206 1207 This function only does the minimum work necessary for letting the 1208 user "name" things symbolically; it does not read the entire symtab. 1209 Instead, it reads the external and static symbols and puts them in partial 1210 symbol tables. When more extensive information is requested of a 1211 file, the corresponding partial symbol table is mutated into a full 1212 fledged symbol table by going back and reading the symbols 1213 for real. 1214 1215 We look for sections with specific names, to tell us what debug 1216 format to look for: FIXME!!! 1217 1218 elfstab_build_psymtabs() handles STABS symbols; 1219 mdebug_build_psymtabs() handles ECOFF debugging information. 1220 1221 Note that ELF files have a "minimal" symbol table, which looks a lot 1222 like a COFF symbol table, but has only the minimal information necessary 1223 for linking. We process this also, and use the information to 1224 build gdb's minimal symbol table. This gives us some minimal debugging 1225 capability even for files compiled without -g. */ 1226 1227 static void 1228 elf_symfile_read (struct objfile *objfile, int symfile_flags) 1229 { 1230 bfd *abfd = objfile->obfd; 1231 struct elfinfo ei; 1232 struct cleanup *back_to; 1233 long symcount = 0, dynsymcount = 0, synthcount, storage_needed; 1234 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL; 1235 asymbol *synthsyms; 1236 1237 init_minimal_symbol_collection (); 1238 back_to = make_cleanup_discard_minimal_symbols (); 1239 1240 memset ((char *) &ei, 0, sizeof (ei)); 1241 1242 /* Allocate struct to keep track of the symfile. */ 1243 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *) 1244 xmalloc (sizeof (struct dbx_symfile_info)); 1245 memset ((char *) objfile->deprecated_sym_stab_info, 1246 0, sizeof (struct dbx_symfile_info)); 1247 make_cleanup (free_elfinfo, (void *) objfile); 1248 1249 /* Process the normal ELF symbol table first. This may write some 1250 chain of info into the dbx_symfile_info in 1251 objfile->deprecated_sym_stab_info, which can later be used by 1252 elfstab_offset_sections. */ 1253 1254 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd); 1255 if (storage_needed < 0) 1256 error (_("Can't read symbols from %s: %s"), 1257 bfd_get_filename (objfile->obfd), 1258 bfd_errmsg (bfd_get_error ())); 1259 1260 if (storage_needed > 0) 1261 { 1262 symbol_table = (asymbol **) xmalloc (storage_needed); 1263 make_cleanup (xfree, symbol_table); 1264 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table); 1265 1266 if (symcount < 0) 1267 error (_("Can't read symbols from %s: %s"), 1268 bfd_get_filename (objfile->obfd), 1269 bfd_errmsg (bfd_get_error ())); 1270 1271 elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0); 1272 } 1273 1274 /* Add the dynamic symbols. */ 1275 1276 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd); 1277 1278 if (storage_needed > 0) 1279 { 1280 /* Memory gets permanently referenced from ABFD after 1281 bfd_get_synthetic_symtab so it must not get freed before ABFD gets. 1282 It happens only in the case when elf_slurp_reloc_table sees 1283 asection->relocation NULL. Determining which section is asection is 1284 done by _bfd_elf_get_synthetic_symtab which is all a bfd 1285 implementation detail, though. */ 1286 1287 dyn_symbol_table = bfd_alloc (abfd, storage_needed); 1288 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd, 1289 dyn_symbol_table); 1290 1291 if (dynsymcount < 0) 1292 error (_("Can't read symbols from %s: %s"), 1293 bfd_get_filename (objfile->obfd), 1294 bfd_errmsg (bfd_get_error ())); 1295 1296 elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0); 1297 1298 elf_rel_plt_read (objfile, dyn_symbol_table); 1299 } 1300 1301 /* Add synthetic symbols - for instance, names for any PLT entries. */ 1302 1303 synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table, 1304 dynsymcount, dyn_symbol_table, 1305 &synthsyms); 1306 if (synthcount > 0) 1307 { 1308 asymbol **synth_symbol_table; 1309 long i; 1310 1311 make_cleanup (xfree, synthsyms); 1312 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount); 1313 for (i = 0; i < synthcount; i++) 1314 synth_symbol_table[i] = synthsyms + i; 1315 make_cleanup (xfree, synth_symbol_table); 1316 elf_symtab_read (objfile, ST_SYNTHETIC, synthcount, 1317 synth_symbol_table, 1); 1318 } 1319 1320 /* Install any minimal symbols that have been collected as the current 1321 minimal symbols for this objfile. The debug readers below this point 1322 should not generate new minimal symbols; if they do it's their 1323 responsibility to install them. "mdebug" appears to be the only one 1324 which will do this. */ 1325 1326 install_minimal_symbols (objfile); 1327 do_cleanups (back_to); 1328 1329 /* Now process debugging information, which is contained in 1330 special ELF sections. */ 1331 1332 /* We first have to find them... */ 1333 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei); 1334 1335 /* ELF debugging information is inserted into the psymtab in the 1336 order of least informative first - most informative last. Since 1337 the psymtab table is searched `most recent insertion first' this 1338 increases the probability that more detailed debug information 1339 for a section is found. 1340 1341 For instance, an object file might contain both .mdebug (XCOFF) 1342 and .debug_info (DWARF2) sections then .mdebug is inserted first 1343 (searched last) and DWARF2 is inserted last (searched first). If 1344 we don't do this then the XCOFF info is found first - for code in 1345 an included file XCOFF info is useless. */ 1346 1347 if (ei.mdebugsect) 1348 { 1349 const struct ecoff_debug_swap *swap; 1350 1351 /* .mdebug section, presumably holding ECOFF debugging 1352 information. */ 1353 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; 1354 if (swap) 1355 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect); 1356 } 1357 if (ei.stabsect) 1358 { 1359 asection *str_sect; 1360 1361 /* Stab sections have an associated string table that looks like 1362 a separate section. */ 1363 str_sect = bfd_get_section_by_name (abfd, ".stabstr"); 1364 1365 /* FIXME should probably warn about a stab section without a stabstr. */ 1366 if (str_sect) 1367 elfstab_build_psymtabs (objfile, 1368 ei.stabsect, 1369 str_sect->filepos, 1370 bfd_section_size (abfd, str_sect)); 1371 } 1372 1373 if (dwarf2_has_info (objfile)) 1374 { 1375 /* elf_sym_fns_gdb_index cannot handle simultaneous non-DWARF debug 1376 information present in OBJFILE. If there is such debug info present 1377 never use .gdb_index. */ 1378 1379 if (!objfile_has_partial_symbols (objfile) 1380 && dwarf2_initialize_objfile (objfile)) 1381 objfile->sf = &elf_sym_fns_gdb_index; 1382 else 1383 { 1384 /* It is ok to do this even if the stabs reader made some 1385 partial symbols, because OBJF_PSYMTABS_READ has not been 1386 set, and so our lazy reader function will still be called 1387 when needed. */ 1388 objfile->sf = &elf_sym_fns_lazy_psyms; 1389 } 1390 } 1391 /* If the file has its own symbol tables it has no separate debug 1392 info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to 1393 SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with 1394 `.note.gnu.build-id'. */ 1395 else if (!objfile_has_partial_symbols (objfile)) 1396 { 1397 char *debugfile; 1398 1399 debugfile = find_separate_debug_file_by_buildid (objfile); 1400 1401 if (debugfile == NULL) 1402 debugfile = find_separate_debug_file_by_debuglink (objfile); 1403 1404 if (debugfile) 1405 { 1406 bfd *abfd = symfile_bfd_open (debugfile); 1407 1408 symbol_file_add_separate (abfd, symfile_flags, objfile); 1409 xfree (debugfile); 1410 } 1411 } 1412 } 1413 1414 /* Callback to lazily read psymtabs. */ 1415 1416 static void 1417 read_psyms (struct objfile *objfile) 1418 { 1419 if (dwarf2_has_info (objfile)) 1420 dwarf2_build_psymtabs (objfile); 1421 } 1422 1423 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and 1424 the chain of stab_section_info's, that might be dangling from 1425 it. */ 1426 1427 static void 1428 free_elfinfo (void *objp) 1429 { 1430 struct objfile *objfile = (struct objfile *) objp; 1431 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info; 1432 struct stab_section_info *ssi, *nssi; 1433 1434 ssi = dbxinfo->stab_section_info; 1435 while (ssi) 1436 { 1437 nssi = ssi->next; 1438 xfree (ssi); 1439 ssi = nssi; 1440 } 1441 1442 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ 1443 } 1444 1445 1446 /* Initialize anything that needs initializing when a completely new symbol 1447 file is specified (not just adding some symbols from another file, e.g. a 1448 shared library). 1449 1450 We reinitialize buildsym, since we may be reading stabs from an ELF 1451 file. */ 1452 1453 static void 1454 elf_new_init (struct objfile *ignore) 1455 { 1456 stabsread_new_init (); 1457 buildsym_new_init (); 1458 } 1459 1460 /* Perform any local cleanups required when we are done with a particular 1461 objfile. I.E, we are in the process of discarding all symbol information 1462 for an objfile, freeing up all memory held for it, and unlinking the 1463 objfile struct from the global list of known objfiles. */ 1464 1465 static void 1466 elf_symfile_finish (struct objfile *objfile) 1467 { 1468 if (objfile->deprecated_sym_stab_info != NULL) 1469 { 1470 xfree (objfile->deprecated_sym_stab_info); 1471 } 1472 1473 dwarf2_free_objfile (objfile); 1474 } 1475 1476 /* ELF specific initialization routine for reading symbols. 1477 1478 It is passed a pointer to a struct sym_fns which contains, among other 1479 things, the BFD for the file whose symbols are being read, and a slot for 1480 a pointer to "private data" which we can fill with goodies. 1481 1482 For now at least, we have nothing in particular to do, so this function is 1483 just a stub. */ 1484 1485 static void 1486 elf_symfile_init (struct objfile *objfile) 1487 { 1488 /* ELF objects may be reordered, so set OBJF_REORDERED. If we 1489 find this causes a significant slowdown in gdb then we could 1490 set it in the debug symbol readers only when necessary. */ 1491 objfile->flags |= OBJF_REORDERED; 1492 } 1493 1494 /* When handling an ELF file that contains Sun STABS debug info, 1495 some of the debug info is relative to the particular chunk of the 1496 section that was generated in its individual .o file. E.g. 1497 offsets to static variables are relative to the start of the data 1498 segment *for that module before linking*. This information is 1499 painfully squirreled away in the ELF symbol table as local symbols 1500 with wierd names. Go get 'em when needed. */ 1501 1502 void 1503 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst) 1504 { 1505 const char *filename = pst->filename; 1506 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; 1507 struct stab_section_info *maybe = dbx->stab_section_info; 1508 struct stab_section_info *questionable = 0; 1509 int i; 1510 1511 /* The ELF symbol info doesn't include path names, so strip the path 1512 (if any) from the psymtab filename. */ 1513 filename = lbasename (filename); 1514 1515 /* FIXME: This linear search could speed up significantly 1516 if it was chained in the right order to match how we search it, 1517 and if we unchained when we found a match. */ 1518 for (; maybe; maybe = maybe->next) 1519 { 1520 if (filename[0] == maybe->filename[0] 1521 && filename_cmp (filename, maybe->filename) == 0) 1522 { 1523 /* We found a match. But there might be several source files 1524 (from different directories) with the same name. */ 1525 if (0 == maybe->found) 1526 break; 1527 questionable = maybe; /* Might use it later. */ 1528 } 1529 } 1530 1531 if (maybe == 0 && questionable != 0) 1532 { 1533 complaint (&symfile_complaints, 1534 _("elf/stab section information questionable for %s"), 1535 filename); 1536 maybe = questionable; 1537 } 1538 1539 if (maybe) 1540 { 1541 /* Found it! Allocate a new psymtab struct, and fill it in. */ 1542 maybe->found++; 1543 pst->section_offsets = (struct section_offsets *) 1544 obstack_alloc (&objfile->objfile_obstack, 1545 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections)); 1546 for (i = 0; i < maybe->num_sections; i++) 1547 (pst->section_offsets)->offsets[i] = maybe->sections[i]; 1548 return; 1549 } 1550 1551 /* We were unable to find any offsets for this file. Complain. */ 1552 if (dbx->stab_section_info) /* If there *is* any info, */ 1553 complaint (&symfile_complaints, 1554 _("elf/stab section information missing for %s"), filename); 1555 } 1556 1557 /* Register that we are able to handle ELF object file formats. */ 1558 1559 static const struct sym_fns elf_sym_fns = 1560 { 1561 bfd_target_elf_flavour, 1562 elf_new_init, /* init anything gbl to entire symtab */ 1563 elf_symfile_init, /* read initial info, setup for sym_read() */ 1564 elf_symfile_read, /* read a symbol file into symtab */ 1565 NULL, /* sym_read_psymbols */ 1566 elf_symfile_finish, /* finished with file, cleanup */ 1567 default_symfile_offsets, /* Translate ext. to int. relocation */ 1568 elf_symfile_segments, /* Get segment information from a file. */ 1569 NULL, 1570 default_symfile_relocate, /* Relocate a debug section. */ 1571 &psym_functions 1572 }; 1573 1574 /* The same as elf_sym_fns, but not registered and lazily reads 1575 psymbols. */ 1576 1577 static const struct sym_fns elf_sym_fns_lazy_psyms = 1578 { 1579 bfd_target_elf_flavour, 1580 elf_new_init, /* init anything gbl to entire symtab */ 1581 elf_symfile_init, /* read initial info, setup for sym_read() */ 1582 elf_symfile_read, /* read a symbol file into symtab */ 1583 read_psyms, /* sym_read_psymbols */ 1584 elf_symfile_finish, /* finished with file, cleanup */ 1585 default_symfile_offsets, /* Translate ext. to int. relocation */ 1586 elf_symfile_segments, /* Get segment information from a file. */ 1587 NULL, 1588 default_symfile_relocate, /* Relocate a debug section. */ 1589 &psym_functions 1590 }; 1591 1592 /* The same as elf_sym_fns, but not registered and uses the 1593 DWARF-specific GNU index rather than psymtab. */ 1594 static const struct sym_fns elf_sym_fns_gdb_index = 1595 { 1596 bfd_target_elf_flavour, 1597 elf_new_init, /* init anything gbl to entire symab */ 1598 elf_symfile_init, /* read initial info, setup for sym_red() */ 1599 elf_symfile_read, /* read a symbol file into symtab */ 1600 NULL, /* sym_read_psymbols */ 1601 elf_symfile_finish, /* finished with file, cleanup */ 1602 default_symfile_offsets, /* Translate ext. to int. relocatin */ 1603 elf_symfile_segments, /* Get segment information from a file. */ 1604 NULL, 1605 default_symfile_relocate, /* Relocate a debug section. */ 1606 &dwarf2_gdb_index_functions 1607 }; 1608 1609 /* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p. */ 1610 1611 static const struct gnu_ifunc_fns elf_gnu_ifunc_fns = 1612 { 1613 elf_gnu_ifunc_resolve_addr, 1614 elf_gnu_ifunc_resolve_name, 1615 elf_gnu_ifunc_resolver_stop, 1616 elf_gnu_ifunc_resolver_return_stop 1617 }; 1618 1619 void 1620 _initialize_elfread (void) 1621 { 1622 add_symtab_fns (&elf_sym_fns); 1623 1624 elf_objfile_gnu_ifunc_cache_data = register_objfile_data (); 1625 gnu_ifunc_fns_p = &elf_gnu_ifunc_fns; 1626 } 1627