gdb/
[deliverable/binutils-gdb.git] / gdb / elfread.c
1 /* Read ELF (Executable and Linking Format) object files for GDB.
2
3 Copyright (C) 1991-2012 Free Software Foundation, Inc.
4
5 Written by Fred Fish at Cygnus Support.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #include "defs.h"
23 #include "bfd.h"
24 #include "gdb_string.h"
25 #include "elf-bfd.h"
26 #include "elf/common.h"
27 #include "elf/internal.h"
28 #include "elf/mips.h"
29 #include "symtab.h"
30 #include "symfile.h"
31 #include "objfiles.h"
32 #include "buildsym.h"
33 #include "stabsread.h"
34 #include "gdb-stabs.h"
35 #include "complaints.h"
36 #include "demangle.h"
37 #include "psympriv.h"
38 #include "filenames.h"
39 #include "probe.h"
40 #include "arch-utils.h"
41 #include "gdbtypes.h"
42 #include "value.h"
43 #include "infcall.h"
44 #include "gdbthread.h"
45 #include "regcache.h"
46 #include "bcache.h"
47
48 extern void _initialize_elfread (void);
49
50 /* Forward declarations. */
51 static const struct sym_fns elf_sym_fns_gdb_index;
52 static const struct sym_fns elf_sym_fns_lazy_psyms;
53
54 /* The struct elfinfo is available only during ELF symbol table and
55 psymtab reading. It is destroyed at the completion of psymtab-reading.
56 It's local to elf_symfile_read. */
57
58 struct elfinfo
59 {
60 asection *stabsect; /* Section pointer for .stab section */
61 asection *stabindexsect; /* Section pointer for .stab.index section */
62 asection *mdebugsect; /* Section pointer for .mdebug section */
63 };
64
65 /* Per-objfile data for probe info. */
66
67 static const struct objfile_data *probe_key = NULL;
68
69 static void free_elfinfo (void *);
70
71 /* Minimal symbols located at the GOT entries for .plt - that is the real
72 pointer where the given entry will jump to. It gets updated by the real
73 function address during lazy ld.so resolving in the inferior. These
74 minimal symbols are indexed for <tab>-completion. */
75
76 #define SYMBOL_GOT_PLT_SUFFIX "@got.plt"
77
78 /* Locate the segments in ABFD. */
79
80 static struct symfile_segment_data *
81 elf_symfile_segments (bfd *abfd)
82 {
83 Elf_Internal_Phdr *phdrs, **segments;
84 long phdrs_size;
85 int num_phdrs, num_segments, num_sections, i;
86 asection *sect;
87 struct symfile_segment_data *data;
88
89 phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
90 if (phdrs_size == -1)
91 return NULL;
92
93 phdrs = alloca (phdrs_size);
94 num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
95 if (num_phdrs == -1)
96 return NULL;
97
98 num_segments = 0;
99 segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs);
100 for (i = 0; i < num_phdrs; i++)
101 if (phdrs[i].p_type == PT_LOAD)
102 segments[num_segments++] = &phdrs[i];
103
104 if (num_segments == 0)
105 return NULL;
106
107 data = XZALLOC (struct symfile_segment_data);
108 data->num_segments = num_segments;
109 data->segment_bases = XCALLOC (num_segments, CORE_ADDR);
110 data->segment_sizes = XCALLOC (num_segments, CORE_ADDR);
111
112 for (i = 0; i < num_segments; i++)
113 {
114 data->segment_bases[i] = segments[i]->p_vaddr;
115 data->segment_sizes[i] = segments[i]->p_memsz;
116 }
117
118 num_sections = bfd_count_sections (abfd);
119 data->segment_info = XCALLOC (num_sections, int);
120
121 for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
122 {
123 int j;
124 CORE_ADDR vma;
125
126 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
127 continue;
128
129 vma = bfd_get_section_vma (abfd, sect);
130
131 for (j = 0; j < num_segments; j++)
132 if (segments[j]->p_memsz > 0
133 && vma >= segments[j]->p_vaddr
134 && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
135 {
136 data->segment_info[i] = j + 1;
137 break;
138 }
139
140 /* We should have found a segment for every non-empty section.
141 If we haven't, we will not relocate this section by any
142 offsets we apply to the segments. As an exception, do not
143 warn about SHT_NOBITS sections; in normal ELF execution
144 environments, SHT_NOBITS means zero-initialized and belongs
145 in a segment, but in no-OS environments some tools (e.g. ARM
146 RealView) use SHT_NOBITS for uninitialized data. Since it is
147 uninitialized, it doesn't need a program header. Such
148 binaries are not relocatable. */
149 if (bfd_get_section_size (sect) > 0 && j == num_segments
150 && (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0)
151 warning (_("Loadable section \"%s\" outside of ELF segments"),
152 bfd_section_name (abfd, sect));
153 }
154
155 return data;
156 }
157
158 /* We are called once per section from elf_symfile_read. We
159 need to examine each section we are passed, check to see
160 if it is something we are interested in processing, and
161 if so, stash away some access information for the section.
162
163 For now we recognize the dwarf debug information sections and
164 line number sections from matching their section names. The
165 ELF definition is no real help here since it has no direct
166 knowledge of DWARF (by design, so any debugging format can be
167 used).
168
169 We also recognize the ".stab" sections used by the Sun compilers
170 released with Solaris 2.
171
172 FIXME: The section names should not be hardwired strings (what
173 should they be? I don't think most object file formats have enough
174 section flags to specify what kind of debug section it is.
175 -kingdon). */
176
177 static void
178 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
179 {
180 struct elfinfo *ei;
181
182 ei = (struct elfinfo *) eip;
183 if (strcmp (sectp->name, ".stab") == 0)
184 {
185 ei->stabsect = sectp;
186 }
187 else if (strcmp (sectp->name, ".stab.index") == 0)
188 {
189 ei->stabindexsect = sectp;
190 }
191 else if (strcmp (sectp->name, ".mdebug") == 0)
192 {
193 ei->mdebugsect = sectp;
194 }
195 }
196
197 static struct minimal_symbol *
198 record_minimal_symbol (const char *name, int name_len, int copy_name,
199 CORE_ADDR address,
200 enum minimal_symbol_type ms_type,
201 asection *bfd_section, struct objfile *objfile)
202 {
203 struct gdbarch *gdbarch = get_objfile_arch (objfile);
204
205 if (ms_type == mst_text || ms_type == mst_file_text
206 || ms_type == mst_text_gnu_ifunc)
207 address = gdbarch_smash_text_address (gdbarch, address);
208
209 return prim_record_minimal_symbol_full (name, name_len, copy_name, address,
210 ms_type, bfd_section->index,
211 bfd_section, objfile);
212 }
213
214 /* Read the symbol table of an ELF file.
215
216 Given an objfile, a symbol table, and a flag indicating whether the
217 symbol table contains regular, dynamic, or synthetic symbols, add all
218 the global function and data symbols to the minimal symbol table.
219
220 In stabs-in-ELF, as implemented by Sun, there are some local symbols
221 defined in the ELF symbol table, which can be used to locate
222 the beginnings of sections from each ".o" file that was linked to
223 form the executable objfile. We gather any such info and record it
224 in data structures hung off the objfile's private data. */
225
226 #define ST_REGULAR 0
227 #define ST_DYNAMIC 1
228 #define ST_SYNTHETIC 2
229
230 static void
231 elf_symtab_read (struct objfile *objfile, int type,
232 long number_of_symbols, asymbol **symbol_table,
233 int copy_names)
234 {
235 struct gdbarch *gdbarch = get_objfile_arch (objfile);
236 asymbol *sym;
237 long i;
238 CORE_ADDR symaddr;
239 CORE_ADDR offset;
240 enum minimal_symbol_type ms_type;
241 /* If sectinfo is nonNULL, it contains section info that should end up
242 filed in the objfile. */
243 struct stab_section_info *sectinfo = NULL;
244 /* If filesym is nonzero, it points to a file symbol, but we haven't
245 seen any section info for it yet. */
246 asymbol *filesym = 0;
247 /* Name of filesym. This is either a constant string or is saved on
248 the objfile's filename cache. */
249 const char *filesymname = "";
250 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
251 int stripped = (bfd_get_symcount (objfile->obfd) == 0);
252
253 for (i = 0; i < number_of_symbols; i++)
254 {
255 sym = symbol_table[i];
256 if (sym->name == NULL || *sym->name == '\0')
257 {
258 /* Skip names that don't exist (shouldn't happen), or names
259 that are null strings (may happen). */
260 continue;
261 }
262
263 /* Skip "special" symbols, e.g. ARM mapping symbols. These are
264 symbols which do not correspond to objects in the symbol table,
265 but have some other target-specific meaning. */
266 if (bfd_is_target_special_symbol (objfile->obfd, sym))
267 {
268 if (gdbarch_record_special_symbol_p (gdbarch))
269 gdbarch_record_special_symbol (gdbarch, objfile, sym);
270 continue;
271 }
272
273 offset = ANOFFSET (objfile->section_offsets, sym->section->index);
274 if (type == ST_DYNAMIC
275 && sym->section == bfd_und_section_ptr
276 && (sym->flags & BSF_FUNCTION))
277 {
278 struct minimal_symbol *msym;
279 bfd *abfd = objfile->obfd;
280 asection *sect;
281
282 /* Symbol is a reference to a function defined in
283 a shared library.
284 If its value is non zero then it is usually the address
285 of the corresponding entry in the procedure linkage table,
286 plus the desired section offset.
287 If its value is zero then the dynamic linker has to resolve
288 the symbol. We are unable to find any meaningful address
289 for this symbol in the executable file, so we skip it. */
290 symaddr = sym->value;
291 if (symaddr == 0)
292 continue;
293
294 /* sym->section is the undefined section. However, we want to
295 record the section where the PLT stub resides with the
296 minimal symbol. Search the section table for the one that
297 covers the stub's address. */
298 for (sect = abfd->sections; sect != NULL; sect = sect->next)
299 {
300 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
301 continue;
302
303 if (symaddr >= bfd_get_section_vma (abfd, sect)
304 && symaddr < bfd_get_section_vma (abfd, sect)
305 + bfd_get_section_size (sect))
306 break;
307 }
308 if (!sect)
309 continue;
310
311 /* On ia64-hpux, we have discovered that the system linker
312 adds undefined symbols with nonzero addresses that cannot
313 be right (their address points inside the code of another
314 function in the .text section). This creates problems
315 when trying to determine which symbol corresponds to
316 a given address.
317
318 We try to detect those buggy symbols by checking which
319 section we think they correspond to. Normally, PLT symbols
320 are stored inside their own section, and the typical name
321 for that section is ".plt". So, if there is a ".plt"
322 section, and yet the section name of our symbol does not
323 start with ".plt", we ignore that symbol. */
324 if (strncmp (sect->name, ".plt", 4) != 0
325 && bfd_get_section_by_name (abfd, ".plt") != NULL)
326 continue;
327
328 symaddr += ANOFFSET (objfile->section_offsets, sect->index);
329
330 msym = record_minimal_symbol
331 (sym->name, strlen (sym->name), copy_names,
332 symaddr, mst_solib_trampoline, sect, objfile);
333 if (msym != NULL)
334 msym->filename = filesymname;
335 continue;
336 }
337
338 /* If it is a nonstripped executable, do not enter dynamic
339 symbols, as the dynamic symbol table is usually a subset
340 of the main symbol table. */
341 if (type == ST_DYNAMIC && !stripped)
342 continue;
343 if (sym->flags & BSF_FILE)
344 {
345 /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
346 Chain any old one onto the objfile; remember new sym. */
347 if (sectinfo != NULL)
348 {
349 sectinfo->next = dbx->stab_section_info;
350 dbx->stab_section_info = sectinfo;
351 sectinfo = NULL;
352 }
353 filesym = sym;
354 filesymname = bcache (filesym->name, strlen (filesym->name) + 1,
355 objfile->filename_cache);
356 }
357 else if (sym->flags & BSF_SECTION_SYM)
358 continue;
359 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
360 {
361 struct minimal_symbol *msym;
362
363 /* Select global/local/weak symbols. Note that bfd puts abs
364 symbols in their own section, so all symbols we are
365 interested in will have a section. */
366 /* Bfd symbols are section relative. */
367 symaddr = sym->value + sym->section->vma;
368 /* Relocate all non-absolute and non-TLS symbols by the
369 section offset. */
370 if (sym->section != bfd_abs_section_ptr
371 && !(sym->section->flags & SEC_THREAD_LOCAL))
372 {
373 symaddr += offset;
374 }
375 /* For non-absolute symbols, use the type of the section
376 they are relative to, to intuit text/data. Bfd provides
377 no way of figuring this out for absolute symbols. */
378 if (sym->section == bfd_abs_section_ptr)
379 {
380 /* This is a hack to get the minimal symbol type
381 right for Irix 5, which has absolute addresses
382 with special section indices for dynamic symbols.
383
384 NOTE: uweigand-20071112: Synthetic symbols do not
385 have an ELF-private part, so do not touch those. */
386 unsigned int shndx = type == ST_SYNTHETIC ? 0 :
387 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
388
389 switch (shndx)
390 {
391 case SHN_MIPS_TEXT:
392 ms_type = mst_text;
393 break;
394 case SHN_MIPS_DATA:
395 ms_type = mst_data;
396 break;
397 case SHN_MIPS_ACOMMON:
398 ms_type = mst_bss;
399 break;
400 default:
401 ms_type = mst_abs;
402 }
403
404 /* If it is an Irix dynamic symbol, skip section name
405 symbols, relocate all others by section offset. */
406 if (ms_type != mst_abs)
407 {
408 if (sym->name[0] == '.')
409 continue;
410 symaddr += offset;
411 }
412 }
413 else if (sym->section->flags & SEC_CODE)
414 {
415 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
416 {
417 if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
418 ms_type = mst_text_gnu_ifunc;
419 else
420 ms_type = mst_text;
421 }
422 /* The BSF_SYNTHETIC check is there to omit ppc64 function
423 descriptors mistaken for static functions starting with 'L'.
424 */
425 else if ((sym->name[0] == '.' && sym->name[1] == 'L'
426 && (sym->flags & BSF_SYNTHETIC) == 0)
427 || ((sym->flags & BSF_LOCAL)
428 && sym->name[0] == '$'
429 && sym->name[1] == 'L'))
430 /* Looks like a compiler-generated label. Skip
431 it. The assembler should be skipping these (to
432 keep executables small), but apparently with
433 gcc on the (deleted) delta m88k SVR4, it loses.
434 So to have us check too should be harmless (but
435 I encourage people to fix this in the assembler
436 instead of adding checks here). */
437 continue;
438 else
439 {
440 ms_type = mst_file_text;
441 }
442 }
443 else if (sym->section->flags & SEC_ALLOC)
444 {
445 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
446 {
447 if (sym->section->flags & SEC_LOAD)
448 {
449 ms_type = mst_data;
450 }
451 else
452 {
453 ms_type = mst_bss;
454 }
455 }
456 else if (sym->flags & BSF_LOCAL)
457 {
458 /* Named Local variable in a Data section.
459 Check its name for stabs-in-elf. */
460 int special_local_sect;
461
462 if (strcmp ("Bbss.bss", sym->name) == 0)
463 special_local_sect = SECT_OFF_BSS (objfile);
464 else if (strcmp ("Ddata.data", sym->name) == 0)
465 special_local_sect = SECT_OFF_DATA (objfile);
466 else if (strcmp ("Drodata.rodata", sym->name) == 0)
467 special_local_sect = SECT_OFF_RODATA (objfile);
468 else
469 special_local_sect = -1;
470 if (special_local_sect >= 0)
471 {
472 /* Found a special local symbol. Allocate a
473 sectinfo, if needed, and fill it in. */
474 if (sectinfo == NULL)
475 {
476 int max_index;
477 size_t size;
478
479 max_index = SECT_OFF_BSS (objfile);
480 if (objfile->sect_index_data > max_index)
481 max_index = objfile->sect_index_data;
482 if (objfile->sect_index_rodata > max_index)
483 max_index = objfile->sect_index_rodata;
484
485 /* max_index is the largest index we'll
486 use into this array, so we must
487 allocate max_index+1 elements for it.
488 However, 'struct stab_section_info'
489 already includes one element, so we
490 need to allocate max_index aadditional
491 elements. */
492 size = (sizeof (struct stab_section_info)
493 + (sizeof (CORE_ADDR) * max_index));
494 sectinfo = (struct stab_section_info *)
495 xmalloc (size);
496 memset (sectinfo, 0, size);
497 sectinfo->num_sections = max_index;
498 if (filesym == NULL)
499 {
500 complaint (&symfile_complaints,
501 _("elf/stab section information %s "
502 "without a preceding file symbol"),
503 sym->name);
504 }
505 else
506 {
507 sectinfo->filename =
508 (char *) filesym->name;
509 }
510 }
511 if (sectinfo->sections[special_local_sect] != 0)
512 complaint (&symfile_complaints,
513 _("duplicated elf/stab section "
514 "information for %s"),
515 sectinfo->filename);
516 /* BFD symbols are section relative. */
517 symaddr = sym->value + sym->section->vma;
518 /* Relocate non-absolute symbols by the
519 section offset. */
520 if (sym->section != bfd_abs_section_ptr)
521 symaddr += offset;
522 sectinfo->sections[special_local_sect] = symaddr;
523 /* The special local symbols don't go in the
524 minimal symbol table, so ignore this one. */
525 continue;
526 }
527 /* Not a special stabs-in-elf symbol, do regular
528 symbol processing. */
529 if (sym->section->flags & SEC_LOAD)
530 {
531 ms_type = mst_file_data;
532 }
533 else
534 {
535 ms_type = mst_file_bss;
536 }
537 }
538 else
539 {
540 ms_type = mst_unknown;
541 }
542 }
543 else
544 {
545 /* FIXME: Solaris2 shared libraries include lots of
546 odd "absolute" and "undefined" symbols, that play
547 hob with actions like finding what function the PC
548 is in. Ignore them if they aren't text, data, or bss. */
549 /* ms_type = mst_unknown; */
550 continue; /* Skip this symbol. */
551 }
552 msym = record_minimal_symbol
553 (sym->name, strlen (sym->name), copy_names, symaddr,
554 ms_type, sym->section, objfile);
555
556 if (msym)
557 {
558 /* Pass symbol size field in via BFD. FIXME!!! */
559 elf_symbol_type *elf_sym;
560
561 /* NOTE: uweigand-20071112: A synthetic symbol does not have an
562 ELF-private part. However, in some cases (e.g. synthetic
563 'dot' symbols on ppc64) the udata.p entry is set to point back
564 to the original ELF symbol it was derived from. Get the size
565 from that symbol. */
566 if (type != ST_SYNTHETIC)
567 elf_sym = (elf_symbol_type *) sym;
568 else
569 elf_sym = (elf_symbol_type *) sym->udata.p;
570
571 if (elf_sym)
572 MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size;
573
574 msym->filename = filesymname;
575 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
576 }
577
578 /* For @plt symbols, also record a trampoline to the
579 destination symbol. The @plt symbol will be used in
580 disassembly, and the trampoline will be used when we are
581 trying to find the target. */
582 if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
583 {
584 int len = strlen (sym->name);
585
586 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
587 {
588 struct minimal_symbol *mtramp;
589
590 mtramp = record_minimal_symbol (sym->name, len - 4, 1,
591 symaddr,
592 mst_solib_trampoline,
593 sym->section, objfile);
594 if (mtramp)
595 {
596 MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym);
597 mtramp->created_by_gdb = 1;
598 mtramp->filename = filesymname;
599 gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
600 }
601 }
602 }
603 }
604 }
605 }
606
607 /* Build minimal symbols named `function@got.plt' (see SYMBOL_GOT_PLT_SUFFIX)
608 for later look ups of which function to call when user requests
609 a STT_GNU_IFUNC function. As the STT_GNU_IFUNC type is found at the target
610 library defining `function' we cannot yet know while reading OBJFILE which
611 of the SYMBOL_GOT_PLT_SUFFIX entries will be needed and later
612 DYN_SYMBOL_TABLE is no longer easily available for OBJFILE. */
613
614 static void
615 elf_rel_plt_read (struct objfile *objfile, asymbol **dyn_symbol_table)
616 {
617 bfd *obfd = objfile->obfd;
618 const struct elf_backend_data *bed = get_elf_backend_data (obfd);
619 asection *plt, *relplt, *got_plt;
620 int plt_elf_idx;
621 bfd_size_type reloc_count, reloc;
622 char *string_buffer = NULL;
623 size_t string_buffer_size = 0;
624 struct cleanup *back_to;
625 struct gdbarch *gdbarch = objfile->gdbarch;
626 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
627 size_t ptr_size = TYPE_LENGTH (ptr_type);
628
629 if (objfile->separate_debug_objfile_backlink)
630 return;
631
632 plt = bfd_get_section_by_name (obfd, ".plt");
633 if (plt == NULL)
634 return;
635 plt_elf_idx = elf_section_data (plt)->this_idx;
636
637 got_plt = bfd_get_section_by_name (obfd, ".got.plt");
638 if (got_plt == NULL)
639 return;
640
641 /* This search algorithm is from _bfd_elf_canonicalize_dynamic_reloc. */
642 for (relplt = obfd->sections; relplt != NULL; relplt = relplt->next)
643 if (elf_section_data (relplt)->this_hdr.sh_info == plt_elf_idx
644 && (elf_section_data (relplt)->this_hdr.sh_type == SHT_REL
645 || elf_section_data (relplt)->this_hdr.sh_type == SHT_RELA))
646 break;
647 if (relplt == NULL)
648 return;
649
650 if (! bed->s->slurp_reloc_table (obfd, relplt, dyn_symbol_table, TRUE))
651 return;
652
653 back_to = make_cleanup (free_current_contents, &string_buffer);
654
655 reloc_count = relplt->size / elf_section_data (relplt)->this_hdr.sh_entsize;
656 for (reloc = 0; reloc < reloc_count; reloc++)
657 {
658 const char *name;
659 struct minimal_symbol *msym;
660 CORE_ADDR address;
661 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
662 size_t name_len;
663
664 name = bfd_asymbol_name (*relplt->relocation[reloc].sym_ptr_ptr);
665 name_len = strlen (name);
666 address = relplt->relocation[reloc].address;
667
668 /* Does the pointer reside in the .got.plt section? */
669 if (!(bfd_get_section_vma (obfd, got_plt) <= address
670 && address < bfd_get_section_vma (obfd, got_plt)
671 + bfd_get_section_size (got_plt)))
672 continue;
673
674 /* We cannot check if NAME is a reference to mst_text_gnu_ifunc as in
675 OBJFILE the symbol is undefined and the objfile having NAME defined
676 may not yet have been loaded. */
677
678 if (string_buffer_size < name_len + got_suffix_len + 1)
679 {
680 string_buffer_size = 2 * (name_len + got_suffix_len);
681 string_buffer = xrealloc (string_buffer, string_buffer_size);
682 }
683 memcpy (string_buffer, name, name_len);
684 memcpy (&string_buffer[name_len], SYMBOL_GOT_PLT_SUFFIX,
685 got_suffix_len + 1);
686
687 msym = record_minimal_symbol (string_buffer, name_len + got_suffix_len,
688 1, address, mst_slot_got_plt, got_plt,
689 objfile);
690 if (msym)
691 MSYMBOL_SIZE (msym) = ptr_size;
692 }
693
694 do_cleanups (back_to);
695 }
696
697 /* The data pointer is htab_t for gnu_ifunc_record_cache_unchecked. */
698
699 static const struct objfile_data *elf_objfile_gnu_ifunc_cache_data;
700
701 /* Map function names to CORE_ADDR in elf_objfile_gnu_ifunc_cache_data. */
702
703 struct elf_gnu_ifunc_cache
704 {
705 /* This is always a function entry address, not a function descriptor. */
706 CORE_ADDR addr;
707
708 char name[1];
709 };
710
711 /* htab_hash for elf_objfile_gnu_ifunc_cache_data. */
712
713 static hashval_t
714 elf_gnu_ifunc_cache_hash (const void *a_voidp)
715 {
716 const struct elf_gnu_ifunc_cache *a = a_voidp;
717
718 return htab_hash_string (a->name);
719 }
720
721 /* htab_eq for elf_objfile_gnu_ifunc_cache_data. */
722
723 static int
724 elf_gnu_ifunc_cache_eq (const void *a_voidp, const void *b_voidp)
725 {
726 const struct elf_gnu_ifunc_cache *a = a_voidp;
727 const struct elf_gnu_ifunc_cache *b = b_voidp;
728
729 return strcmp (a->name, b->name) == 0;
730 }
731
732 /* Record the target function address of a STT_GNU_IFUNC function NAME is the
733 function entry address ADDR. Return 1 if NAME and ADDR are considered as
734 valid and therefore they were successfully recorded, return 0 otherwise.
735
736 Function does not expect a duplicate entry. Use
737 elf_gnu_ifunc_resolve_by_cache first to check if the entry for NAME already
738 exists. */
739
740 static int
741 elf_gnu_ifunc_record_cache (const char *name, CORE_ADDR addr)
742 {
743 struct minimal_symbol *msym;
744 asection *sect;
745 struct objfile *objfile;
746 htab_t htab;
747 struct elf_gnu_ifunc_cache entry_local, *entry_p;
748 void **slot;
749
750 msym = lookup_minimal_symbol_by_pc (addr);
751 if (msym == NULL)
752 return 0;
753 if (SYMBOL_VALUE_ADDRESS (msym) != addr)
754 return 0;
755 /* minimal symbols have always SYMBOL_OBJ_SECTION non-NULL. */
756 sect = SYMBOL_OBJ_SECTION (msym)->the_bfd_section;
757 objfile = SYMBOL_OBJ_SECTION (msym)->objfile;
758
759 /* If .plt jumps back to .plt the symbol is still deferred for later
760 resolution and it has no use for GDB. Besides ".text" this symbol can
761 reside also in ".opd" for ppc64 function descriptor. */
762 if (strcmp (bfd_get_section_name (objfile->obfd, sect), ".plt") == 0)
763 return 0;
764
765 htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data);
766 if (htab == NULL)
767 {
768 htab = htab_create_alloc_ex (1, elf_gnu_ifunc_cache_hash,
769 elf_gnu_ifunc_cache_eq,
770 NULL, &objfile->objfile_obstack,
771 hashtab_obstack_allocate,
772 dummy_obstack_deallocate);
773 set_objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data, htab);
774 }
775
776 entry_local.addr = addr;
777 obstack_grow (&objfile->objfile_obstack, &entry_local,
778 offsetof (struct elf_gnu_ifunc_cache, name));
779 obstack_grow_str0 (&objfile->objfile_obstack, name);
780 entry_p = obstack_finish (&objfile->objfile_obstack);
781
782 slot = htab_find_slot (htab, entry_p, INSERT);
783 if (*slot != NULL)
784 {
785 struct elf_gnu_ifunc_cache *entry_found_p = *slot;
786 struct gdbarch *gdbarch = objfile->gdbarch;
787
788 if (entry_found_p->addr != addr)
789 {
790 /* This case indicates buggy inferior program, the resolved address
791 should never change. */
792
793 warning (_("gnu-indirect-function \"%s\" has changed its resolved "
794 "function_address from %s to %s"),
795 name, paddress (gdbarch, entry_found_p->addr),
796 paddress (gdbarch, addr));
797 }
798
799 /* New ENTRY_P is here leaked/duplicate in the OBJFILE obstack. */
800 }
801 *slot = entry_p;
802
803 return 1;
804 }
805
806 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC
807 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
808 is not NULL) and the function returns 1. It returns 0 otherwise.
809
810 Only the elf_objfile_gnu_ifunc_cache_data hash table is searched by this
811 function. */
812
813 static int
814 elf_gnu_ifunc_resolve_by_cache (const char *name, CORE_ADDR *addr_p)
815 {
816 struct objfile *objfile;
817
818 ALL_PSPACE_OBJFILES (current_program_space, objfile)
819 {
820 htab_t htab;
821 struct elf_gnu_ifunc_cache *entry_p;
822 void **slot;
823
824 htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data);
825 if (htab == NULL)
826 continue;
827
828 entry_p = alloca (sizeof (*entry_p) + strlen (name));
829 strcpy (entry_p->name, name);
830
831 slot = htab_find_slot (htab, entry_p, NO_INSERT);
832 if (slot == NULL)
833 continue;
834 entry_p = *slot;
835 gdb_assert (entry_p != NULL);
836
837 if (addr_p)
838 *addr_p = entry_p->addr;
839 return 1;
840 }
841
842 return 0;
843 }
844
845 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC
846 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
847 is not NULL) and the function returns 1. It returns 0 otherwise.
848
849 Only the SYMBOL_GOT_PLT_SUFFIX locations are searched by this function.
850 elf_gnu_ifunc_resolve_by_cache must have been already called for NAME to
851 prevent cache entries duplicates. */
852
853 static int
854 elf_gnu_ifunc_resolve_by_got (const char *name, CORE_ADDR *addr_p)
855 {
856 char *name_got_plt;
857 struct objfile *objfile;
858 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
859
860 name_got_plt = alloca (strlen (name) + got_suffix_len + 1);
861 sprintf (name_got_plt, "%s" SYMBOL_GOT_PLT_SUFFIX, name);
862
863 ALL_PSPACE_OBJFILES (current_program_space, objfile)
864 {
865 bfd *obfd = objfile->obfd;
866 struct gdbarch *gdbarch = objfile->gdbarch;
867 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
868 size_t ptr_size = TYPE_LENGTH (ptr_type);
869 CORE_ADDR pointer_address, addr;
870 asection *plt;
871 gdb_byte *buf = alloca (ptr_size);
872 struct minimal_symbol *msym;
873
874 msym = lookup_minimal_symbol (name_got_plt, NULL, objfile);
875 if (msym == NULL)
876 continue;
877 if (MSYMBOL_TYPE (msym) != mst_slot_got_plt)
878 continue;
879 pointer_address = SYMBOL_VALUE_ADDRESS (msym);
880
881 plt = bfd_get_section_by_name (obfd, ".plt");
882 if (plt == NULL)
883 continue;
884
885 if (MSYMBOL_SIZE (msym) != ptr_size)
886 continue;
887 if (target_read_memory (pointer_address, buf, ptr_size) != 0)
888 continue;
889 addr = extract_typed_address (buf, ptr_type);
890 addr = gdbarch_convert_from_func_ptr_addr (gdbarch, addr,
891 &current_target);
892
893 if (addr_p)
894 *addr_p = addr;
895 if (elf_gnu_ifunc_record_cache (name, addr))
896 return 1;
897 }
898
899 return 0;
900 }
901
902 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC
903 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
904 is not NULL) and the function returns 1. It returns 0 otherwise.
905
906 Both the elf_objfile_gnu_ifunc_cache_data hash table and
907 SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. */
908
909 static int
910 elf_gnu_ifunc_resolve_name (const char *name, CORE_ADDR *addr_p)
911 {
912 if (elf_gnu_ifunc_resolve_by_cache (name, addr_p))
913 return 1;
914
915 if (elf_gnu_ifunc_resolve_by_got (name, addr_p))
916 return 1;
917
918 return 0;
919 }
920
921 /* Call STT_GNU_IFUNC - a function returning addresss of a real function to
922 call. PC is theSTT_GNU_IFUNC resolving function entry. The value returned
923 is the entry point of the resolved STT_GNU_IFUNC target function to call.
924 */
925
926 static CORE_ADDR
927 elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
928 {
929 const char *name_at_pc;
930 CORE_ADDR start_at_pc, address;
931 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
932 struct value *function, *address_val;
933
934 /* Try first any non-intrusive methods without an inferior call. */
935
936 if (find_pc_partial_function (pc, &name_at_pc, &start_at_pc, NULL)
937 && start_at_pc == pc)
938 {
939 if (elf_gnu_ifunc_resolve_name (name_at_pc, &address))
940 return address;
941 }
942 else
943 name_at_pc = NULL;
944
945 function = allocate_value (func_func_type);
946 set_value_address (function, pc);
947
948 /* STT_GNU_IFUNC resolver functions have no parameters. FUNCTION is the
949 function entry address. ADDRESS may be a function descriptor. */
950
951 address_val = call_function_by_hand (function, 0, NULL);
952 address = value_as_address (address_val);
953 address = gdbarch_convert_from_func_ptr_addr (gdbarch, address,
954 &current_target);
955
956 if (name_at_pc)
957 elf_gnu_ifunc_record_cache (name_at_pc, address);
958
959 return address;
960 }
961
962 /* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition. */
963
964 static void
965 elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
966 {
967 struct breakpoint *b_return;
968 struct frame_info *prev_frame = get_prev_frame (get_current_frame ());
969 struct frame_id prev_frame_id = get_stack_frame_id (prev_frame);
970 CORE_ADDR prev_pc = get_frame_pc (prev_frame);
971 int thread_id = pid_to_thread_id (inferior_ptid);
972
973 gdb_assert (b->type == bp_gnu_ifunc_resolver);
974
975 for (b_return = b->related_breakpoint; b_return != b;
976 b_return = b_return->related_breakpoint)
977 {
978 gdb_assert (b_return->type == bp_gnu_ifunc_resolver_return);
979 gdb_assert (b_return->loc != NULL && b_return->loc->next == NULL);
980 gdb_assert (frame_id_p (b_return->frame_id));
981
982 if (b_return->thread == thread_id
983 && b_return->loc->requested_address == prev_pc
984 && frame_id_eq (b_return->frame_id, prev_frame_id))
985 break;
986 }
987
988 if (b_return == b)
989 {
990 struct symtab_and_line sal;
991
992 /* No need to call find_pc_line for symbols resolving as this is only
993 a helper breakpointer never shown to the user. */
994
995 init_sal (&sal);
996 sal.pspace = current_inferior ()->pspace;
997 sal.pc = prev_pc;
998 sal.section = find_pc_overlay (sal.pc);
999 sal.explicit_pc = 1;
1000 b_return = set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
1001 prev_frame_id,
1002 bp_gnu_ifunc_resolver_return);
1003
1004 /* set_momentary_breakpoint invalidates PREV_FRAME. */
1005 prev_frame = NULL;
1006
1007 /* Add new b_return to the ring list b->related_breakpoint. */
1008 gdb_assert (b_return->related_breakpoint == b_return);
1009 b_return->related_breakpoint = b->related_breakpoint;
1010 b->related_breakpoint = b_return;
1011 }
1012 }
1013
1014 /* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition. */
1015
1016 static void
1017 elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
1018 {
1019 struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
1020 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
1021 struct type *value_type = TYPE_TARGET_TYPE (func_func_type);
1022 struct regcache *regcache = get_thread_regcache (inferior_ptid);
1023 struct value *func_func;
1024 struct value *value;
1025 CORE_ADDR resolved_address, resolved_pc;
1026 struct symtab_and_line sal;
1027 struct symtabs_and_lines sals, sals_end;
1028
1029 gdb_assert (b->type == bp_gnu_ifunc_resolver_return);
1030
1031 while (b->related_breakpoint != b)
1032 {
1033 struct breakpoint *b_next = b->related_breakpoint;
1034
1035 switch (b->type)
1036 {
1037 case bp_gnu_ifunc_resolver:
1038 break;
1039 case bp_gnu_ifunc_resolver_return:
1040 delete_breakpoint (b);
1041 break;
1042 default:
1043 internal_error (__FILE__, __LINE__,
1044 _("handle_inferior_event: Invalid "
1045 "gnu-indirect-function breakpoint type %d"),
1046 (int) b->type);
1047 }
1048 b = b_next;
1049 }
1050 gdb_assert (b->type == bp_gnu_ifunc_resolver);
1051 gdb_assert (b->loc->next == NULL);
1052
1053 func_func = allocate_value (func_func_type);
1054 set_value_address (func_func, b->loc->related_address);
1055
1056 value = allocate_value (value_type);
1057 gdbarch_return_value (gdbarch, func_func, value_type, regcache,
1058 value_contents_raw (value), NULL);
1059 resolved_address = value_as_address (value);
1060 resolved_pc = gdbarch_convert_from_func_ptr_addr (gdbarch,
1061 resolved_address,
1062 &current_target);
1063
1064 gdb_assert (current_program_space == b->pspace || b->pspace == NULL);
1065 elf_gnu_ifunc_record_cache (b->addr_string, resolved_pc);
1066
1067 sal = find_pc_line (resolved_pc, 0);
1068 sals.nelts = 1;
1069 sals.sals = &sal;
1070 sals_end.nelts = 0;
1071
1072 b->type = bp_breakpoint;
1073 update_breakpoint_locations (b, sals, sals_end);
1074 }
1075
1076 struct build_id
1077 {
1078 size_t size;
1079 gdb_byte data[1];
1080 };
1081
1082 /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
1083
1084 static struct build_id *
1085 build_id_bfd_get (bfd *abfd)
1086 {
1087 struct build_id *retval;
1088
1089 if (!bfd_check_format (abfd, bfd_object)
1090 || bfd_get_flavour (abfd) != bfd_target_elf_flavour
1091 || elf_tdata (abfd)->build_id == NULL)
1092 return NULL;
1093
1094 retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size);
1095 retval->size = elf_tdata (abfd)->build_id_size;
1096 memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size);
1097
1098 return retval;
1099 }
1100
1101 /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
1102
1103 static int
1104 build_id_verify (const char *filename, struct build_id *check)
1105 {
1106 bfd *abfd;
1107 struct build_id *found = NULL;
1108 int retval = 0;
1109
1110 /* We expect to be silent on the non-existing files. */
1111 abfd = bfd_open_maybe_remote (filename);
1112 if (abfd == NULL)
1113 return 0;
1114
1115 found = build_id_bfd_get (abfd);
1116
1117 if (found == NULL)
1118 warning (_("File \"%s\" has no build-id, file skipped"), filename);
1119 else if (found->size != check->size
1120 || memcmp (found->data, check->data, found->size) != 0)
1121 warning (_("File \"%s\" has a different build-id, file skipped"),
1122 filename);
1123 else
1124 retval = 1;
1125
1126 gdb_bfd_close_or_warn (abfd);
1127
1128 xfree (found);
1129
1130 return retval;
1131 }
1132
1133 static char *
1134 build_id_to_debug_filename (struct build_id *build_id)
1135 {
1136 char *link, *debugdir, *retval = NULL;
1137 VEC (char_ptr) *debugdir_vec;
1138 struct cleanup *back_to;
1139 int ix;
1140
1141 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
1142 link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
1143 + 2 * build_id->size + (sizeof ".debug" - 1) + 1);
1144
1145 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
1146 cause "/.build-id/..." lookups. */
1147
1148 debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory);
1149 back_to = make_cleanup_free_char_ptr_vec (debugdir_vec);
1150
1151 for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix)
1152 {
1153 size_t debugdir_len = strlen (debugdir);
1154 gdb_byte *data = build_id->data;
1155 size_t size = build_id->size;
1156 char *s;
1157
1158 memcpy (link, debugdir, debugdir_len);
1159 s = &link[debugdir_len];
1160 s += sprintf (s, "/.build-id/");
1161 if (size > 0)
1162 {
1163 size--;
1164 s += sprintf (s, "%02x", (unsigned) *data++);
1165 }
1166 if (size > 0)
1167 *s++ = '/';
1168 while (size-- > 0)
1169 s += sprintf (s, "%02x", (unsigned) *data++);
1170 strcpy (s, ".debug");
1171
1172 /* lrealpath() is expensive even for the usually non-existent files. */
1173 if (access (link, F_OK) == 0)
1174 retval = lrealpath (link);
1175
1176 if (retval != NULL && !build_id_verify (retval, build_id))
1177 {
1178 xfree (retval);
1179 retval = NULL;
1180 }
1181
1182 if (retval != NULL)
1183 break;
1184 }
1185
1186 do_cleanups (back_to);
1187 return retval;
1188 }
1189
1190 static char *
1191 find_separate_debug_file_by_buildid (struct objfile *objfile)
1192 {
1193 struct build_id *build_id;
1194
1195 build_id = build_id_bfd_get (objfile->obfd);
1196 if (build_id != NULL)
1197 {
1198 char *build_id_name;
1199
1200 build_id_name = build_id_to_debug_filename (build_id);
1201 xfree (build_id);
1202 /* Prevent looping on a stripped .debug file. */
1203 if (build_id_name != NULL
1204 && filename_cmp (build_id_name, objfile->name) == 0)
1205 {
1206 warning (_("\"%s\": separate debug info file has no debug info"),
1207 build_id_name);
1208 xfree (build_id_name);
1209 }
1210 else if (build_id_name != NULL)
1211 return build_id_name;
1212 }
1213 return NULL;
1214 }
1215
1216 /* Scan and build partial symbols for a symbol file.
1217 We have been initialized by a call to elf_symfile_init, which
1218 currently does nothing.
1219
1220 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
1221 in each section. We simplify it down to a single offset for all
1222 symbols. FIXME.
1223
1224 This function only does the minimum work necessary for letting the
1225 user "name" things symbolically; it does not read the entire symtab.
1226 Instead, it reads the external and static symbols and puts them in partial
1227 symbol tables. When more extensive information is requested of a
1228 file, the corresponding partial symbol table is mutated into a full
1229 fledged symbol table by going back and reading the symbols
1230 for real.
1231
1232 We look for sections with specific names, to tell us what debug
1233 format to look for: FIXME!!!
1234
1235 elfstab_build_psymtabs() handles STABS symbols;
1236 mdebug_build_psymtabs() handles ECOFF debugging information.
1237
1238 Note that ELF files have a "minimal" symbol table, which looks a lot
1239 like a COFF symbol table, but has only the minimal information necessary
1240 for linking. We process this also, and use the information to
1241 build gdb's minimal symbol table. This gives us some minimal debugging
1242 capability even for files compiled without -g. */
1243
1244 static void
1245 elf_symfile_read (struct objfile *objfile, int symfile_flags)
1246 {
1247 bfd *synth_abfd, *abfd = objfile->obfd;
1248 struct elfinfo ei;
1249 struct cleanup *back_to;
1250 long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
1251 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
1252 asymbol *synthsyms;
1253
1254 if (symtab_create_debug)
1255 {
1256 fprintf_unfiltered (gdb_stdlog,
1257 "Reading minimal symbols of objfile %s ...\n",
1258 objfile->name);
1259 }
1260
1261 init_minimal_symbol_collection ();
1262 back_to = make_cleanup_discard_minimal_symbols ();
1263
1264 memset ((char *) &ei, 0, sizeof (ei));
1265
1266 /* Allocate struct to keep track of the symfile. */
1267 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *)
1268 xmalloc (sizeof (struct dbx_symfile_info));
1269 memset ((char *) objfile->deprecated_sym_stab_info,
1270 0, sizeof (struct dbx_symfile_info));
1271 make_cleanup (free_elfinfo, (void *) objfile);
1272
1273 /* Process the normal ELF symbol table first. This may write some
1274 chain of info into the dbx_symfile_info in
1275 objfile->deprecated_sym_stab_info, which can later be used by
1276 elfstab_offset_sections. */
1277
1278 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
1279 if (storage_needed < 0)
1280 error (_("Can't read symbols from %s: %s"),
1281 bfd_get_filename (objfile->obfd),
1282 bfd_errmsg (bfd_get_error ()));
1283
1284 if (storage_needed > 0)
1285 {
1286 symbol_table = (asymbol **) xmalloc (storage_needed);
1287 make_cleanup (xfree, symbol_table);
1288 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
1289
1290 if (symcount < 0)
1291 error (_("Can't read symbols from %s: %s"),
1292 bfd_get_filename (objfile->obfd),
1293 bfd_errmsg (bfd_get_error ()));
1294
1295 elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0);
1296 }
1297
1298 /* Add the dynamic symbols. */
1299
1300 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
1301
1302 if (storage_needed > 0)
1303 {
1304 /* Memory gets permanently referenced from ABFD after
1305 bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
1306 It happens only in the case when elf_slurp_reloc_table sees
1307 asection->relocation NULL. Determining which section is asection is
1308 done by _bfd_elf_get_synthetic_symtab which is all a bfd
1309 implementation detail, though. */
1310
1311 dyn_symbol_table = bfd_alloc (abfd, storage_needed);
1312 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
1313 dyn_symbol_table);
1314
1315 if (dynsymcount < 0)
1316 error (_("Can't read symbols from %s: %s"),
1317 bfd_get_filename (objfile->obfd),
1318 bfd_errmsg (bfd_get_error ()));
1319
1320 elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0);
1321
1322 elf_rel_plt_read (objfile, dyn_symbol_table);
1323 }
1324
1325 /* Contrary to binutils --strip-debug/--only-keep-debug the strip command from
1326 elfutils (eu-strip) moves even the .symtab section into the .debug file.
1327
1328 bfd_get_synthetic_symtab on ppc64 for each function descriptor ELF symbol
1329 'name' creates a new BSF_SYNTHETIC ELF symbol '.name' with its code
1330 address. But with eu-strip files bfd_get_synthetic_symtab would fail to
1331 read the code address from .opd while it reads the .symtab section from
1332 a separate debug info file as the .opd section is SHT_NOBITS there.
1333
1334 With SYNTH_ABFD the .opd section will be read from the original
1335 backlinked binary where it is valid. */
1336
1337 if (objfile->separate_debug_objfile_backlink)
1338 synth_abfd = objfile->separate_debug_objfile_backlink->obfd;
1339 else
1340 synth_abfd = abfd;
1341
1342 /* Add synthetic symbols - for instance, names for any PLT entries. */
1343
1344 synthcount = bfd_get_synthetic_symtab (synth_abfd, symcount, symbol_table,
1345 dynsymcount, dyn_symbol_table,
1346 &synthsyms);
1347 if (synthcount > 0)
1348 {
1349 asymbol **synth_symbol_table;
1350 long i;
1351
1352 make_cleanup (xfree, synthsyms);
1353 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount);
1354 for (i = 0; i < synthcount; i++)
1355 synth_symbol_table[i] = synthsyms + i;
1356 make_cleanup (xfree, synth_symbol_table);
1357 elf_symtab_read (objfile, ST_SYNTHETIC, synthcount,
1358 synth_symbol_table, 1);
1359 }
1360
1361 /* Install any minimal symbols that have been collected as the current
1362 minimal symbols for this objfile. The debug readers below this point
1363 should not generate new minimal symbols; if they do it's their
1364 responsibility to install them. "mdebug" appears to be the only one
1365 which will do this. */
1366
1367 install_minimal_symbols (objfile);
1368 do_cleanups (back_to);
1369
1370 /* Now process debugging information, which is contained in
1371 special ELF sections. */
1372
1373 /* We first have to find them... */
1374 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
1375
1376 /* ELF debugging information is inserted into the psymtab in the
1377 order of least informative first - most informative last. Since
1378 the psymtab table is searched `most recent insertion first' this
1379 increases the probability that more detailed debug information
1380 for a section is found.
1381
1382 For instance, an object file might contain both .mdebug (XCOFF)
1383 and .debug_info (DWARF2) sections then .mdebug is inserted first
1384 (searched last) and DWARF2 is inserted last (searched first). If
1385 we don't do this then the XCOFF info is found first - for code in
1386 an included file XCOFF info is useless. */
1387
1388 if (ei.mdebugsect)
1389 {
1390 const struct ecoff_debug_swap *swap;
1391
1392 /* .mdebug section, presumably holding ECOFF debugging
1393 information. */
1394 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
1395 if (swap)
1396 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
1397 }
1398 if (ei.stabsect)
1399 {
1400 asection *str_sect;
1401
1402 /* Stab sections have an associated string table that looks like
1403 a separate section. */
1404 str_sect = bfd_get_section_by_name (abfd, ".stabstr");
1405
1406 /* FIXME should probably warn about a stab section without a stabstr. */
1407 if (str_sect)
1408 elfstab_build_psymtabs (objfile,
1409 ei.stabsect,
1410 str_sect->filepos,
1411 bfd_section_size (abfd, str_sect));
1412 }
1413
1414 if (dwarf2_has_info (objfile, NULL))
1415 {
1416 /* elf_sym_fns_gdb_index cannot handle simultaneous non-DWARF debug
1417 information present in OBJFILE. If there is such debug info present
1418 never use .gdb_index. */
1419
1420 if (!objfile_has_partial_symbols (objfile)
1421 && dwarf2_initialize_objfile (objfile))
1422 objfile->sf = &elf_sym_fns_gdb_index;
1423 else
1424 {
1425 /* It is ok to do this even if the stabs reader made some
1426 partial symbols, because OBJF_PSYMTABS_READ has not been
1427 set, and so our lazy reader function will still be called
1428 when needed. */
1429 objfile->sf = &elf_sym_fns_lazy_psyms;
1430 }
1431 }
1432 /* If the file has its own symbol tables it has no separate debug
1433 info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
1434 SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
1435 `.note.gnu.build-id'. */
1436 else if (!objfile_has_partial_symbols (objfile))
1437 {
1438 char *debugfile;
1439
1440 debugfile = find_separate_debug_file_by_buildid (objfile);
1441
1442 if (debugfile == NULL)
1443 debugfile = find_separate_debug_file_by_debuglink (objfile);
1444
1445 if (debugfile)
1446 {
1447 bfd *abfd = symfile_bfd_open (debugfile);
1448
1449 symbol_file_add_separate (abfd, symfile_flags, objfile);
1450 xfree (debugfile);
1451 }
1452 }
1453
1454 if (symtab_create_debug)
1455 fprintf_unfiltered (gdb_stdlog, "Done reading minimal symbols.\n");
1456 }
1457
1458 /* Callback to lazily read psymtabs. */
1459
1460 static void
1461 read_psyms (struct objfile *objfile)
1462 {
1463 if (dwarf2_has_info (objfile, NULL))
1464 dwarf2_build_psymtabs (objfile);
1465 }
1466
1467 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and
1468 the chain of stab_section_info's, that might be dangling from
1469 it. */
1470
1471 static void
1472 free_elfinfo (void *objp)
1473 {
1474 struct objfile *objfile = (struct objfile *) objp;
1475 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info;
1476 struct stab_section_info *ssi, *nssi;
1477
1478 ssi = dbxinfo->stab_section_info;
1479 while (ssi)
1480 {
1481 nssi = ssi->next;
1482 xfree (ssi);
1483 ssi = nssi;
1484 }
1485
1486 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
1487 }
1488
1489
1490 /* Initialize anything that needs initializing when a completely new symbol
1491 file is specified (not just adding some symbols from another file, e.g. a
1492 shared library).
1493
1494 We reinitialize buildsym, since we may be reading stabs from an ELF
1495 file. */
1496
1497 static void
1498 elf_new_init (struct objfile *ignore)
1499 {
1500 stabsread_new_init ();
1501 buildsym_new_init ();
1502 }
1503
1504 /* Perform any local cleanups required when we are done with a particular
1505 objfile. I.E, we are in the process of discarding all symbol information
1506 for an objfile, freeing up all memory held for it, and unlinking the
1507 objfile struct from the global list of known objfiles. */
1508
1509 static void
1510 elf_symfile_finish (struct objfile *objfile)
1511 {
1512 if (objfile->deprecated_sym_stab_info != NULL)
1513 {
1514 xfree (objfile->deprecated_sym_stab_info);
1515 }
1516
1517 dwarf2_free_objfile (objfile);
1518 }
1519
1520 /* ELF specific initialization routine for reading symbols.
1521
1522 It is passed a pointer to a struct sym_fns which contains, among other
1523 things, the BFD for the file whose symbols are being read, and a slot for
1524 a pointer to "private data" which we can fill with goodies.
1525
1526 For now at least, we have nothing in particular to do, so this function is
1527 just a stub. */
1528
1529 static void
1530 elf_symfile_init (struct objfile *objfile)
1531 {
1532 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
1533 find this causes a significant slowdown in gdb then we could
1534 set it in the debug symbol readers only when necessary. */
1535 objfile->flags |= OBJF_REORDERED;
1536 }
1537
1538 /* When handling an ELF file that contains Sun STABS debug info,
1539 some of the debug info is relative to the particular chunk of the
1540 section that was generated in its individual .o file. E.g.
1541 offsets to static variables are relative to the start of the data
1542 segment *for that module before linking*. This information is
1543 painfully squirreled away in the ELF symbol table as local symbols
1544 with wierd names. Go get 'em when needed. */
1545
1546 void
1547 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst)
1548 {
1549 const char *filename = pst->filename;
1550 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
1551 struct stab_section_info *maybe = dbx->stab_section_info;
1552 struct stab_section_info *questionable = 0;
1553 int i;
1554
1555 /* The ELF symbol info doesn't include path names, so strip the path
1556 (if any) from the psymtab filename. */
1557 filename = lbasename (filename);
1558
1559 /* FIXME: This linear search could speed up significantly
1560 if it was chained in the right order to match how we search it,
1561 and if we unchained when we found a match. */
1562 for (; maybe; maybe = maybe->next)
1563 {
1564 if (filename[0] == maybe->filename[0]
1565 && filename_cmp (filename, maybe->filename) == 0)
1566 {
1567 /* We found a match. But there might be several source files
1568 (from different directories) with the same name. */
1569 if (0 == maybe->found)
1570 break;
1571 questionable = maybe; /* Might use it later. */
1572 }
1573 }
1574
1575 if (maybe == 0 && questionable != 0)
1576 {
1577 complaint (&symfile_complaints,
1578 _("elf/stab section information questionable for %s"),
1579 filename);
1580 maybe = questionable;
1581 }
1582
1583 if (maybe)
1584 {
1585 /* Found it! Allocate a new psymtab struct, and fill it in. */
1586 maybe->found++;
1587 pst->section_offsets = (struct section_offsets *)
1588 obstack_alloc (&objfile->objfile_obstack,
1589 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
1590 for (i = 0; i < maybe->num_sections; i++)
1591 (pst->section_offsets)->offsets[i] = maybe->sections[i];
1592 return;
1593 }
1594
1595 /* We were unable to find any offsets for this file. Complain. */
1596 if (dbx->stab_section_info) /* If there *is* any info, */
1597 complaint (&symfile_complaints,
1598 _("elf/stab section information missing for %s"), filename);
1599 }
1600
1601 /* Implementation of `sym_get_probes', as documented in symfile.h. */
1602
1603 static VEC (probe_p) *
1604 elf_get_probes (struct objfile *objfile)
1605 {
1606 VEC (probe_p) *probes_per_objfile;
1607
1608 /* Have we parsed this objfile's probes already? */
1609 probes_per_objfile = objfile_data (objfile, probe_key);
1610
1611 if (!probes_per_objfile)
1612 {
1613 int ix;
1614 const struct probe_ops *probe_ops;
1615
1616 /* Here we try to gather information about all types of probes from the
1617 objfile. */
1618 for (ix = 0; VEC_iterate (probe_ops_cp, all_probe_ops, ix, probe_ops);
1619 ix++)
1620 probe_ops->get_probes (&probes_per_objfile, objfile);
1621
1622 if (probes_per_objfile == NULL)
1623 {
1624 VEC_reserve (probe_p, probes_per_objfile, 1);
1625 gdb_assert (probes_per_objfile != NULL);
1626 }
1627
1628 set_objfile_data (objfile, probe_key, probes_per_objfile);
1629 }
1630
1631 return probes_per_objfile;
1632 }
1633
1634 /* Implementation of `sym_get_probe_argument_count', as documented in
1635 symfile.h. */
1636
1637 static unsigned
1638 elf_get_probe_argument_count (struct objfile *objfile,
1639 struct probe *probe)
1640 {
1641 return probe->pops->get_probe_argument_count (probe, objfile);
1642 }
1643
1644 /* Implementation of `sym_evaluate_probe_argument', as documented in
1645 symfile.h. */
1646
1647 static struct value *
1648 elf_evaluate_probe_argument (struct objfile *objfile,
1649 struct probe *probe,
1650 unsigned n)
1651 {
1652 return probe->pops->evaluate_probe_argument (probe, objfile, n);
1653 }
1654
1655 /* Implementation of `sym_compile_to_ax', as documented in symfile.h. */
1656
1657 static void
1658 elf_compile_to_ax (struct objfile *objfile,
1659 struct probe *probe,
1660 struct agent_expr *expr,
1661 struct axs_value *value,
1662 unsigned n)
1663 {
1664 probe->pops->compile_to_ax (probe, objfile, expr, value, n);
1665 }
1666
1667 /* Implementation of `sym_relocate_probe', as documented in symfile.h. */
1668
1669 static void
1670 elf_symfile_relocate_probe (struct objfile *objfile,
1671 struct section_offsets *new_offsets,
1672 struct section_offsets *delta)
1673 {
1674 int ix;
1675 VEC (probe_p) *probes = objfile_data (objfile, probe_key);
1676 struct probe *probe;
1677
1678 for (ix = 0; VEC_iterate (probe_p, probes, ix, probe); ix++)
1679 probe->pops->relocate (probe, ANOFFSET (delta, SECT_OFF_TEXT (objfile)));
1680 }
1681
1682 /* Helper function used to free the space allocated for storing SystemTap
1683 probe information. */
1684
1685 static void
1686 probe_key_free (struct objfile *objfile, void *d)
1687 {
1688 int ix;
1689 VEC (probe_p) *probes = d;
1690 struct probe *probe;
1691
1692 for (ix = 0; VEC_iterate (probe_p, probes, ix, probe); ix++)
1693 probe->pops->destroy (probe);
1694
1695 VEC_free (probe_p, probes);
1696 }
1697
1698 \f
1699
1700 /* Implementation `sym_probe_fns', as documented in symfile.h. */
1701
1702 static const struct sym_probe_fns elf_probe_fns =
1703 {
1704 elf_get_probes, /* sym_get_probes */
1705 elf_get_probe_argument_count, /* sym_get_probe_argument_count */
1706 elf_evaluate_probe_argument, /* sym_evaluate_probe_argument */
1707 elf_compile_to_ax, /* sym_compile_to_ax */
1708 elf_symfile_relocate_probe, /* sym_relocate_probe */
1709 };
1710
1711 /* Register that we are able to handle ELF object file formats. */
1712
1713 static const struct sym_fns elf_sym_fns =
1714 {
1715 bfd_target_elf_flavour,
1716 elf_new_init, /* init anything gbl to entire symtab */
1717 elf_symfile_init, /* read initial info, setup for sym_read() */
1718 elf_symfile_read, /* read a symbol file into symtab */
1719 NULL, /* sym_read_psymbols */
1720 elf_symfile_finish, /* finished with file, cleanup */
1721 default_symfile_offsets, /* Translate ext. to int. relocation */
1722 elf_symfile_segments, /* Get segment information from a file. */
1723 NULL,
1724 default_symfile_relocate, /* Relocate a debug section. */
1725 &elf_probe_fns, /* sym_probe_fns */
1726 &psym_functions
1727 };
1728
1729 /* The same as elf_sym_fns, but not registered and lazily reads
1730 psymbols. */
1731
1732 static const struct sym_fns elf_sym_fns_lazy_psyms =
1733 {
1734 bfd_target_elf_flavour,
1735 elf_new_init, /* init anything gbl to entire symtab */
1736 elf_symfile_init, /* read initial info, setup for sym_read() */
1737 elf_symfile_read, /* read a symbol file into symtab */
1738 read_psyms, /* sym_read_psymbols */
1739 elf_symfile_finish, /* finished with file, cleanup */
1740 default_symfile_offsets, /* Translate ext. to int. relocation */
1741 elf_symfile_segments, /* Get segment information from a file. */
1742 NULL,
1743 default_symfile_relocate, /* Relocate a debug section. */
1744 &elf_probe_fns, /* sym_probe_fns */
1745 &psym_functions
1746 };
1747
1748 /* The same as elf_sym_fns, but not registered and uses the
1749 DWARF-specific GNU index rather than psymtab. */
1750 static const struct sym_fns elf_sym_fns_gdb_index =
1751 {
1752 bfd_target_elf_flavour,
1753 elf_new_init, /* init anything gbl to entire symab */
1754 elf_symfile_init, /* read initial info, setup for sym_red() */
1755 elf_symfile_read, /* read a symbol file into symtab */
1756 NULL, /* sym_read_psymbols */
1757 elf_symfile_finish, /* finished with file, cleanup */
1758 default_symfile_offsets, /* Translate ext. to int. relocatin */
1759 elf_symfile_segments, /* Get segment information from a file. */
1760 NULL,
1761 default_symfile_relocate, /* Relocate a debug section. */
1762 &elf_probe_fns, /* sym_probe_fns */
1763 &dwarf2_gdb_index_functions
1764 };
1765
1766 /* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p. */
1767
1768 static const struct gnu_ifunc_fns elf_gnu_ifunc_fns =
1769 {
1770 elf_gnu_ifunc_resolve_addr,
1771 elf_gnu_ifunc_resolve_name,
1772 elf_gnu_ifunc_resolver_stop,
1773 elf_gnu_ifunc_resolver_return_stop
1774 };
1775
1776 void
1777 _initialize_elfread (void)
1778 {
1779 probe_key = register_objfile_data_with_cleanup (NULL, probe_key_free);
1780 add_symtab_fns (&elf_sym_fns);
1781
1782 elf_objfile_gnu_ifunc_cache_data = register_objfile_data ();
1783 gnu_ifunc_fns_p = &elf_gnu_ifunc_fns;
1784 }
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