Implement Ada operator overloading
[deliverable/binutils-gdb.git] / gdb / elfread.c
1 /* Read ELF (Executable and Linking Format) object files for GDB.
2
3 Copyright (C) 1991-2021 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 "elf-bfd.h"
25 #include "elf/common.h"
26 #include "elf/internal.h"
27 #include "elf/mips.h"
28 #include "symtab.h"
29 #include "symfile.h"
30 #include "objfiles.h"
31 #include "stabsread.h"
32 #include "complaints.h"
33 #include "demangle.h"
34 #include "psympriv.h"
35 #include "filenames.h"
36 #include "probe.h"
37 #include "arch-utils.h"
38 #include "gdbtypes.h"
39 #include "value.h"
40 #include "infcall.h"
41 #include "gdbthread.h"
42 #include "inferior.h"
43 #include "regcache.h"
44 #include "bcache.h"
45 #include "gdb_bfd.h"
46 #include "build-id.h"
47 #include "location.h"
48 #include "auxv.h"
49 #include "mdebugread.h"
50 #include "ctfread.h"
51 #include "gdbsupport/gdb_string_view.h"
52 #include "gdbsupport/scoped_fd.h"
53 #include "debuginfod-support.h"
54
55 /* Forward declarations. */
56 extern const struct sym_fns elf_sym_fns_gdb_index;
57 extern const struct sym_fns elf_sym_fns_debug_names;
58 extern const struct sym_fns elf_sym_fns_lazy_psyms;
59
60 /* The struct elfinfo is available only during ELF symbol table and
61 psymtab reading. It is destroyed at the completion of psymtab-reading.
62 It's local to elf_symfile_read. */
63
64 struct elfinfo
65 {
66 asection *stabsect; /* Section pointer for .stab section */
67 asection *mdebugsect; /* Section pointer for .mdebug section */
68 asection *ctfsect; /* Section pointer for .ctf section */
69 };
70
71 /* Type for per-BFD data. */
72
73 typedef std::vector<std::unique_ptr<probe>> elfread_data;
74
75 /* Per-BFD data for probe info. */
76
77 static const struct bfd_key<elfread_data> probe_key;
78
79 /* Minimal symbols located at the GOT entries for .plt - that is the real
80 pointer where the given entry will jump to. It gets updated by the real
81 function address during lazy ld.so resolving in the inferior. These
82 minimal symbols are indexed for <tab>-completion. */
83
84 #define SYMBOL_GOT_PLT_SUFFIX "@got.plt"
85
86 /* Locate the segments in ABFD. */
87
88 static symfile_segment_data_up
89 elf_symfile_segments (bfd *abfd)
90 {
91 Elf_Internal_Phdr *phdrs, **segments;
92 long phdrs_size;
93 int num_phdrs, num_segments, num_sections, i;
94 asection *sect;
95
96 phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
97 if (phdrs_size == -1)
98 return NULL;
99
100 phdrs = (Elf_Internal_Phdr *) alloca (phdrs_size);
101 num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
102 if (num_phdrs == -1)
103 return NULL;
104
105 num_segments = 0;
106 segments = XALLOCAVEC (Elf_Internal_Phdr *, num_phdrs);
107 for (i = 0; i < num_phdrs; i++)
108 if (phdrs[i].p_type == PT_LOAD)
109 segments[num_segments++] = &phdrs[i];
110
111 if (num_segments == 0)
112 return NULL;
113
114 symfile_segment_data_up data (new symfile_segment_data);
115 data->segments.reserve (num_segments);
116
117 for (i = 0; i < num_segments; i++)
118 data->segments.emplace_back (segments[i]->p_vaddr, segments[i]->p_memsz);
119
120 num_sections = bfd_count_sections (abfd);
121
122 /* All elements are initialized to 0 (map to no segment). */
123 data->segment_info.resize (num_sections);
124
125 for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
126 {
127 int j;
128
129 if ((bfd_section_flags (sect) & SEC_ALLOC) == 0)
130 continue;
131
132 Elf_Internal_Shdr *this_hdr = &elf_section_data (sect)->this_hdr;
133
134 for (j = 0; j < num_segments; j++)
135 if (ELF_SECTION_IN_SEGMENT (this_hdr, segments[j]))
136 {
137 data->segment_info[i] = j + 1;
138 break;
139 }
140
141 /* We should have found a segment for every non-empty section.
142 If we haven't, we will not relocate this section by any
143 offsets we apply to the segments. As an exception, do not
144 warn about SHT_NOBITS sections; in normal ELF execution
145 environments, SHT_NOBITS means zero-initialized and belongs
146 in a segment, but in no-OS environments some tools (e.g. ARM
147 RealView) use SHT_NOBITS for uninitialized data. Since it is
148 uninitialized, it doesn't need a program header. Such
149 binaries are not relocatable. */
150
151 /* Exclude debuginfo files from this warning, too, since those
152 are often not strictly compliant with the standard. See, e.g.,
153 ld/24717 for more discussion. */
154 if (!is_debuginfo_file (abfd)
155 && bfd_section_size (sect) > 0 && j == num_segments
156 && (bfd_section_flags (sect) & SEC_LOAD) != 0)
157 warning (_("Loadable section \"%s\" outside of ELF segments\n in %s"),
158 bfd_section_name (sect), bfd_get_filename (abfd));
159 }
160
161 return data;
162 }
163
164 /* We are called once per section from elf_symfile_read. We
165 need to examine each section we are passed, check to see
166 if it is something we are interested in processing, and
167 if so, stash away some access information for the section.
168
169 For now we recognize the dwarf debug information sections and
170 line number sections from matching their section names. The
171 ELF definition is no real help here since it has no direct
172 knowledge of DWARF (by design, so any debugging format can be
173 used).
174
175 We also recognize the ".stab" sections used by the Sun compilers
176 released with Solaris 2.
177
178 FIXME: The section names should not be hardwired strings (what
179 should they be? I don't think most object file formats have enough
180 section flags to specify what kind of debug section it is.
181 -kingdon). */
182
183 static void
184 elf_locate_sections (asection *sectp, struct elfinfo *ei)
185 {
186 if (strcmp (sectp->name, ".stab") == 0)
187 {
188 ei->stabsect = sectp;
189 }
190 else if (strcmp (sectp->name, ".mdebug") == 0)
191 {
192 ei->mdebugsect = sectp;
193 }
194 else if (strcmp (sectp->name, ".ctf") == 0)
195 {
196 ei->ctfsect = sectp;
197 }
198 }
199
200 static struct minimal_symbol *
201 record_minimal_symbol (minimal_symbol_reader &reader,
202 gdb::string_view name, bool copy_name,
203 CORE_ADDR address,
204 enum minimal_symbol_type ms_type,
205 asection *bfd_section, struct objfile *objfile)
206 {
207 struct gdbarch *gdbarch = objfile->arch ();
208
209 if (ms_type == mst_text || ms_type == mst_file_text
210 || ms_type == mst_text_gnu_ifunc)
211 address = gdbarch_addr_bits_remove (gdbarch, address);
212
213 /* We only setup section information for allocatable sections. Usually
214 we'd only expect to find msymbols for allocatable sections, but if the
215 ELF is malformed then this might not be the case. In that case don't
216 create an msymbol that references an uninitialised section object. */
217 int section_index = 0;
218 if ((bfd_section_flags (bfd_section) & SEC_ALLOC) == SEC_ALLOC)
219 section_index = gdb_bfd_section_index (objfile->obfd, bfd_section);
220
221 struct minimal_symbol *result
222 = reader.record_full (name, copy_name, address, ms_type, section_index);
223 if ((objfile->flags & OBJF_MAINLINE) == 0
224 && (ms_type == mst_data || ms_type == mst_bss))
225 result->maybe_copied = 1;
226
227 return result;
228 }
229
230 /* Read the symbol table of an ELF file.
231
232 Given an objfile, a symbol table, and a flag indicating whether the
233 symbol table contains regular, dynamic, or synthetic symbols, add all
234 the global function and data symbols to the minimal symbol table.
235
236 In stabs-in-ELF, as implemented by Sun, there are some local symbols
237 defined in the ELF symbol table, which can be used to locate
238 the beginnings of sections from each ".o" file that was linked to
239 form the executable objfile. We gather any such info and record it
240 in data structures hung off the objfile's private data. */
241
242 #define ST_REGULAR 0
243 #define ST_DYNAMIC 1
244 #define ST_SYNTHETIC 2
245
246 static void
247 elf_symtab_read (minimal_symbol_reader &reader,
248 struct objfile *objfile, int type,
249 long number_of_symbols, asymbol **symbol_table,
250 bool copy_names)
251 {
252 struct gdbarch *gdbarch = objfile->arch ();
253 asymbol *sym;
254 long i;
255 CORE_ADDR symaddr;
256 enum minimal_symbol_type ms_type;
257 /* Name of the last file symbol. This is either a constant string or is
258 saved on the objfile's filename cache. */
259 const char *filesymname = "";
260 int stripped = (bfd_get_symcount (objfile->obfd) == 0);
261 int elf_make_msymbol_special_p
262 = gdbarch_elf_make_msymbol_special_p (gdbarch);
263
264 for (i = 0; i < number_of_symbols; i++)
265 {
266 sym = symbol_table[i];
267 if (sym->name == NULL || *sym->name == '\0')
268 {
269 /* Skip names that don't exist (shouldn't happen), or names
270 that are null strings (may happen). */
271 continue;
272 }
273
274 /* Skip "special" symbols, e.g. ARM mapping symbols. These are
275 symbols which do not correspond to objects in the symbol table,
276 but have some other target-specific meaning. */
277 if (bfd_is_target_special_symbol (objfile->obfd, sym))
278 {
279 if (gdbarch_record_special_symbol_p (gdbarch))
280 gdbarch_record_special_symbol (gdbarch, objfile, sym);
281 continue;
282 }
283
284 if (type == ST_DYNAMIC
285 && sym->section == bfd_und_section_ptr
286 && (sym->flags & BSF_FUNCTION))
287 {
288 struct minimal_symbol *msym;
289 bfd *abfd = objfile->obfd;
290 asection *sect;
291
292 /* Symbol is a reference to a function defined in
293 a shared library.
294 If its value is non zero then it is usually the address
295 of the corresponding entry in the procedure linkage table,
296 plus the desired section offset.
297 If its value is zero then the dynamic linker has to resolve
298 the symbol. We are unable to find any meaningful address
299 for this symbol in the executable file, so we skip it. */
300 symaddr = sym->value;
301 if (symaddr == 0)
302 continue;
303
304 /* sym->section is the undefined section. However, we want to
305 record the section where the PLT stub resides with the
306 minimal symbol. Search the section table for the one that
307 covers the stub's address. */
308 for (sect = abfd->sections; sect != NULL; sect = sect->next)
309 {
310 if ((bfd_section_flags (sect) & SEC_ALLOC) == 0)
311 continue;
312
313 if (symaddr >= bfd_section_vma (sect)
314 && symaddr < bfd_section_vma (sect)
315 + bfd_section_size (sect))
316 break;
317 }
318 if (!sect)
319 continue;
320
321 /* On ia64-hpux, we have discovered that the system linker
322 adds undefined symbols with nonzero addresses that cannot
323 be right (their address points inside the code of another
324 function in the .text section). This creates problems
325 when trying to determine which symbol corresponds to
326 a given address.
327
328 We try to detect those buggy symbols by checking which
329 section we think they correspond to. Normally, PLT symbols
330 are stored inside their own section, and the typical name
331 for that section is ".plt". So, if there is a ".plt"
332 section, and yet the section name of our symbol does not
333 start with ".plt", we ignore that symbol. */
334 if (!startswith (sect->name, ".plt")
335 && bfd_get_section_by_name (abfd, ".plt") != NULL)
336 continue;
337
338 msym = record_minimal_symbol
339 (reader, sym->name, copy_names,
340 symaddr, mst_solib_trampoline, sect, objfile);
341 if (msym != NULL)
342 {
343 msym->filename = filesymname;
344 if (elf_make_msymbol_special_p)
345 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
346 }
347 continue;
348 }
349
350 /* If it is a nonstripped executable, do not enter dynamic
351 symbols, as the dynamic symbol table is usually a subset
352 of the main symbol table. */
353 if (type == ST_DYNAMIC && !stripped)
354 continue;
355 if (sym->flags & BSF_FILE)
356 filesymname = objfile->intern (sym->name);
357 else if (sym->flags & BSF_SECTION_SYM)
358 continue;
359 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK
360 | BSF_GNU_UNIQUE))
361 {
362 struct minimal_symbol *msym;
363
364 /* Select global/local/weak symbols. Note that bfd puts abs
365 symbols in their own section, so all symbols we are
366 interested in will have a section. */
367 /* Bfd symbols are section relative. */
368 symaddr = sym->value + sym->section->vma;
369 /* For non-absolute symbols, use the type of the section
370 they are relative to, to intuit text/data. Bfd provides
371 no way of figuring this out for absolute symbols. */
372 if (sym->section == bfd_abs_section_ptr)
373 {
374 /* This is a hack to get the minimal symbol type
375 right for Irix 5, which has absolute addresses
376 with special section indices for dynamic symbols.
377
378 NOTE: uweigand-20071112: Synthetic symbols do not
379 have an ELF-private part, so do not touch those. */
380 unsigned int shndx = type == ST_SYNTHETIC ? 0 :
381 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
382
383 switch (shndx)
384 {
385 case SHN_MIPS_TEXT:
386 ms_type = mst_text;
387 break;
388 case SHN_MIPS_DATA:
389 ms_type = mst_data;
390 break;
391 case SHN_MIPS_ACOMMON:
392 ms_type = mst_bss;
393 break;
394 default:
395 ms_type = mst_abs;
396 }
397
398 /* If it is an Irix dynamic symbol, skip section name
399 symbols, relocate all others by section offset. */
400 if (ms_type != mst_abs)
401 {
402 if (sym->name[0] == '.')
403 continue;
404 }
405 }
406 else if (sym->section->flags & SEC_CODE)
407 {
408 if (sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE))
409 {
410 if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
411 ms_type = mst_text_gnu_ifunc;
412 else
413 ms_type = mst_text;
414 }
415 /* The BSF_SYNTHETIC check is there to omit ppc64 function
416 descriptors mistaken for static functions starting with 'L'.
417 */
418 else if ((sym->name[0] == '.' && sym->name[1] == 'L'
419 && (sym->flags & BSF_SYNTHETIC) == 0)
420 || ((sym->flags & BSF_LOCAL)
421 && sym->name[0] == '$'
422 && sym->name[1] == 'L'))
423 /* Looks like a compiler-generated label. Skip
424 it. The assembler should be skipping these (to
425 keep executables small), but apparently with
426 gcc on the (deleted) delta m88k SVR4, it loses.
427 So to have us check too should be harmless (but
428 I encourage people to fix this in the assembler
429 instead of adding checks here). */
430 continue;
431 else
432 {
433 ms_type = mst_file_text;
434 }
435 }
436 else if (sym->section->flags & SEC_ALLOC)
437 {
438 if (sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE))
439 {
440 if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
441 {
442 ms_type = mst_data_gnu_ifunc;
443 }
444 else if (sym->section->flags & SEC_LOAD)
445 {
446 ms_type = mst_data;
447 }
448 else
449 {
450 ms_type = mst_bss;
451 }
452 }
453 else if (sym->flags & BSF_LOCAL)
454 {
455 if (sym->section->flags & SEC_LOAD)
456 {
457 ms_type = mst_file_data;
458 }
459 else
460 {
461 ms_type = mst_file_bss;
462 }
463 }
464 else
465 {
466 ms_type = mst_unknown;
467 }
468 }
469 else
470 {
471 /* FIXME: Solaris2 shared libraries include lots of
472 odd "absolute" and "undefined" symbols, that play
473 hob with actions like finding what function the PC
474 is in. Ignore them if they aren't text, data, or bss. */
475 /* ms_type = mst_unknown; */
476 continue; /* Skip this symbol. */
477 }
478 msym = record_minimal_symbol
479 (reader, sym->name, copy_names, symaddr,
480 ms_type, sym->section, objfile);
481
482 if (msym)
483 {
484 /* NOTE: uweigand-20071112: A synthetic symbol does not have an
485 ELF-private part. */
486 if (type != ST_SYNTHETIC)
487 {
488 /* Pass symbol size field in via BFD. FIXME!!! */
489 elf_symbol_type *elf_sym = (elf_symbol_type *) sym;
490 SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size);
491 }
492
493 msym->filename = filesymname;
494 if (elf_make_msymbol_special_p)
495 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
496 }
497
498 /* If we see a default versioned symbol, install it under
499 its version-less name. */
500 if (msym != NULL)
501 {
502 const char *atsign = strchr (sym->name, '@');
503
504 if (atsign != NULL && atsign[1] == '@' && atsign > sym->name)
505 {
506 int len = atsign - sym->name;
507
508 record_minimal_symbol (reader,
509 gdb::string_view (sym->name, len),
510 true, symaddr, ms_type, sym->section,
511 objfile);
512 }
513 }
514
515 /* For @plt symbols, also record a trampoline to the
516 destination symbol. The @plt symbol will be used in
517 disassembly, and the trampoline will be used when we are
518 trying to find the target. */
519 if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
520 {
521 int len = strlen (sym->name);
522
523 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
524 {
525 struct minimal_symbol *mtramp;
526
527 mtramp = record_minimal_symbol
528 (reader, gdb::string_view (sym->name, len - 4), true,
529 symaddr, mst_solib_trampoline, sym->section, objfile);
530 if (mtramp)
531 {
532 SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
533 mtramp->created_by_gdb = 1;
534 mtramp->filename = filesymname;
535 if (elf_make_msymbol_special_p)
536 gdbarch_elf_make_msymbol_special (gdbarch,
537 sym, mtramp);
538 }
539 }
540 }
541 }
542 }
543 }
544
545 /* Build minimal symbols named `function@got.plt' (see SYMBOL_GOT_PLT_SUFFIX)
546 for later look ups of which function to call when user requests
547 a STT_GNU_IFUNC function. As the STT_GNU_IFUNC type is found at the target
548 library defining `function' we cannot yet know while reading OBJFILE which
549 of the SYMBOL_GOT_PLT_SUFFIX entries will be needed and later
550 DYN_SYMBOL_TABLE is no longer easily available for OBJFILE. */
551
552 static void
553 elf_rel_plt_read (minimal_symbol_reader &reader,
554 struct objfile *objfile, asymbol **dyn_symbol_table)
555 {
556 bfd *obfd = objfile->obfd;
557 const struct elf_backend_data *bed = get_elf_backend_data (obfd);
558 asection *relplt, *got_plt;
559 bfd_size_type reloc_count, reloc;
560 struct gdbarch *gdbarch = objfile->arch ();
561 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
562 size_t ptr_size = TYPE_LENGTH (ptr_type);
563
564 if (objfile->separate_debug_objfile_backlink)
565 return;
566
567 got_plt = bfd_get_section_by_name (obfd, ".got.plt");
568 if (got_plt == NULL)
569 {
570 /* For platforms where there is no separate .got.plt. */
571 got_plt = bfd_get_section_by_name (obfd, ".got");
572 if (got_plt == NULL)
573 return;
574 }
575
576 /* Depending on system, we may find jump slots in a relocation
577 section for either .got.plt or .plt. */
578 asection *plt = bfd_get_section_by_name (obfd, ".plt");
579 int plt_elf_idx = (plt != NULL) ? elf_section_data (plt)->this_idx : -1;
580
581 int got_plt_elf_idx = elf_section_data (got_plt)->this_idx;
582
583 /* This search algorithm is from _bfd_elf_canonicalize_dynamic_reloc. */
584 for (relplt = obfd->sections; relplt != NULL; relplt = relplt->next)
585 {
586 const auto &this_hdr = elf_section_data (relplt)->this_hdr;
587
588 if (this_hdr.sh_type == SHT_REL || this_hdr.sh_type == SHT_RELA)
589 {
590 if (this_hdr.sh_info == plt_elf_idx
591 || this_hdr.sh_info == got_plt_elf_idx)
592 break;
593 }
594 }
595 if (relplt == NULL)
596 return;
597
598 if (! bed->s->slurp_reloc_table (obfd, relplt, dyn_symbol_table, TRUE))
599 return;
600
601 std::string string_buffer;
602
603 /* Does ADDRESS reside in SECTION of OBFD? */
604 auto within_section = [obfd] (asection *section, CORE_ADDR address)
605 {
606 if (section == NULL)
607 return false;
608
609 return (bfd_section_vma (section) <= address
610 && (address < bfd_section_vma (section)
611 + bfd_section_size (section)));
612 };
613
614 reloc_count = relplt->size / elf_section_data (relplt)->this_hdr.sh_entsize;
615 for (reloc = 0; reloc < reloc_count; reloc++)
616 {
617 const char *name;
618 struct minimal_symbol *msym;
619 CORE_ADDR address;
620 const char *got_suffix = SYMBOL_GOT_PLT_SUFFIX;
621 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
622
623 name = bfd_asymbol_name (*relplt->relocation[reloc].sym_ptr_ptr);
624 address = relplt->relocation[reloc].address;
625
626 asection *msym_section;
627
628 /* Does the pointer reside in either the .got.plt or .plt
629 sections? */
630 if (within_section (got_plt, address))
631 msym_section = got_plt;
632 else if (within_section (plt, address))
633 msym_section = plt;
634 else
635 continue;
636
637 /* We cannot check if NAME is a reference to
638 mst_text_gnu_ifunc/mst_data_gnu_ifunc as in OBJFILE the
639 symbol is undefined and the objfile having NAME defined may
640 not yet have been loaded. */
641
642 string_buffer.assign (name);
643 string_buffer.append (got_suffix, got_suffix + got_suffix_len);
644
645 msym = record_minimal_symbol (reader, string_buffer,
646 true, address, mst_slot_got_plt,
647 msym_section, objfile);
648 if (msym)
649 SET_MSYMBOL_SIZE (msym, ptr_size);
650 }
651 }
652
653 /* The data pointer is htab_t for gnu_ifunc_record_cache_unchecked. */
654
655 static const struct objfile_key<htab, htab_deleter>
656 elf_objfile_gnu_ifunc_cache_data;
657
658 /* Map function names to CORE_ADDR in elf_objfile_gnu_ifunc_cache_data. */
659
660 struct elf_gnu_ifunc_cache
661 {
662 /* This is always a function entry address, not a function descriptor. */
663 CORE_ADDR addr;
664
665 char name[1];
666 };
667
668 /* htab_hash for elf_objfile_gnu_ifunc_cache_data. */
669
670 static hashval_t
671 elf_gnu_ifunc_cache_hash (const void *a_voidp)
672 {
673 const struct elf_gnu_ifunc_cache *a
674 = (const struct elf_gnu_ifunc_cache *) a_voidp;
675
676 return htab_hash_string (a->name);
677 }
678
679 /* htab_eq for elf_objfile_gnu_ifunc_cache_data. */
680
681 static int
682 elf_gnu_ifunc_cache_eq (const void *a_voidp, const void *b_voidp)
683 {
684 const struct elf_gnu_ifunc_cache *a
685 = (const struct elf_gnu_ifunc_cache *) a_voidp;
686 const struct elf_gnu_ifunc_cache *b
687 = (const struct elf_gnu_ifunc_cache *) b_voidp;
688
689 return strcmp (a->name, b->name) == 0;
690 }
691
692 /* Record the target function address of a STT_GNU_IFUNC function NAME is the
693 function entry address ADDR. Return 1 if NAME and ADDR are considered as
694 valid and therefore they were successfully recorded, return 0 otherwise.
695
696 Function does not expect a duplicate entry. Use
697 elf_gnu_ifunc_resolve_by_cache first to check if the entry for NAME already
698 exists. */
699
700 static int
701 elf_gnu_ifunc_record_cache (const char *name, CORE_ADDR addr)
702 {
703 struct bound_minimal_symbol msym;
704 struct objfile *objfile;
705 htab_t htab;
706 struct elf_gnu_ifunc_cache entry_local, *entry_p;
707 void **slot;
708
709 msym = lookup_minimal_symbol_by_pc (addr);
710 if (msym.minsym == NULL)
711 return 0;
712 if (BMSYMBOL_VALUE_ADDRESS (msym) != addr)
713 return 0;
714 objfile = msym.objfile;
715
716 /* If .plt jumps back to .plt the symbol is still deferred for later
717 resolution and it has no use for GDB. */
718 const char *target_name = msym.minsym->linkage_name ();
719 size_t len = strlen (target_name);
720
721 /* Note we check the symbol's name instead of checking whether the
722 symbol is in the .plt section because some systems have @plt
723 symbols in the .text section. */
724 if (len > 4 && strcmp (target_name + len - 4, "@plt") == 0)
725 return 0;
726
727 htab = elf_objfile_gnu_ifunc_cache_data.get (objfile);
728 if (htab == NULL)
729 {
730 htab = htab_create_alloc (1, elf_gnu_ifunc_cache_hash,
731 elf_gnu_ifunc_cache_eq,
732 NULL, xcalloc, xfree);
733 elf_objfile_gnu_ifunc_cache_data.set (objfile, htab);
734 }
735
736 entry_local.addr = addr;
737 obstack_grow (&objfile->objfile_obstack, &entry_local,
738 offsetof (struct elf_gnu_ifunc_cache, name));
739 obstack_grow_str0 (&objfile->objfile_obstack, name);
740 entry_p
741 = (struct elf_gnu_ifunc_cache *) obstack_finish (&objfile->objfile_obstack);
742
743 slot = htab_find_slot (htab, entry_p, INSERT);
744 if (*slot != NULL)
745 {
746 struct elf_gnu_ifunc_cache *entry_found_p
747 = (struct elf_gnu_ifunc_cache *) *slot;
748 struct gdbarch *gdbarch = objfile->arch ();
749
750 if (entry_found_p->addr != addr)
751 {
752 /* This case indicates buggy inferior program, the resolved address
753 should never change. */
754
755 warning (_("gnu-indirect-function \"%s\" has changed its resolved "
756 "function_address from %s to %s"),
757 name, paddress (gdbarch, entry_found_p->addr),
758 paddress (gdbarch, addr));
759 }
760
761 /* New ENTRY_P is here leaked/duplicate in the OBJFILE obstack. */
762 }
763 *slot = entry_p;
764
765 return 1;
766 }
767
768 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC
769 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
770 is not NULL) and the function returns 1. It returns 0 otherwise.
771
772 Only the elf_objfile_gnu_ifunc_cache_data hash table is searched by this
773 function. */
774
775 static int
776 elf_gnu_ifunc_resolve_by_cache (const char *name, CORE_ADDR *addr_p)
777 {
778 for (objfile *objfile : current_program_space->objfiles ())
779 {
780 htab_t htab;
781 struct elf_gnu_ifunc_cache *entry_p;
782 void **slot;
783
784 htab = elf_objfile_gnu_ifunc_cache_data.get (objfile);
785 if (htab == NULL)
786 continue;
787
788 entry_p = ((struct elf_gnu_ifunc_cache *)
789 alloca (sizeof (*entry_p) + strlen (name)));
790 strcpy (entry_p->name, name);
791
792 slot = htab_find_slot (htab, entry_p, NO_INSERT);
793 if (slot == NULL)
794 continue;
795 entry_p = (struct elf_gnu_ifunc_cache *) *slot;
796 gdb_assert (entry_p != NULL);
797
798 if (addr_p)
799 *addr_p = entry_p->addr;
800 return 1;
801 }
802
803 return 0;
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 SYMBOL_GOT_PLT_SUFFIX locations are searched by this function.
811 elf_gnu_ifunc_resolve_by_cache must have been already called for NAME to
812 prevent cache entries duplicates. */
813
814 static int
815 elf_gnu_ifunc_resolve_by_got (const char *name, CORE_ADDR *addr_p)
816 {
817 char *name_got_plt;
818 const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
819
820 name_got_plt = (char *) alloca (strlen (name) + got_suffix_len + 1);
821 sprintf (name_got_plt, "%s" SYMBOL_GOT_PLT_SUFFIX, name);
822
823 for (objfile *objfile : current_program_space->objfiles ())
824 {
825 bfd *obfd = objfile->obfd;
826 struct gdbarch *gdbarch = objfile->arch ();
827 struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
828 size_t ptr_size = TYPE_LENGTH (ptr_type);
829 CORE_ADDR pointer_address, addr;
830 asection *plt;
831 gdb_byte *buf = (gdb_byte *) alloca (ptr_size);
832 struct bound_minimal_symbol msym;
833
834 msym = lookup_minimal_symbol (name_got_plt, NULL, objfile);
835 if (msym.minsym == NULL)
836 continue;
837 if (MSYMBOL_TYPE (msym.minsym) != mst_slot_got_plt)
838 continue;
839 pointer_address = BMSYMBOL_VALUE_ADDRESS (msym);
840
841 plt = bfd_get_section_by_name (obfd, ".plt");
842 if (plt == NULL)
843 continue;
844
845 if (MSYMBOL_SIZE (msym.minsym) != ptr_size)
846 continue;
847 if (target_read_memory (pointer_address, buf, ptr_size) != 0)
848 continue;
849 addr = extract_typed_address (buf, ptr_type);
850 addr = gdbarch_convert_from_func_ptr_addr (gdbarch, addr,
851 current_top_target ());
852 addr = gdbarch_addr_bits_remove (gdbarch, addr);
853
854 if (elf_gnu_ifunc_record_cache (name, addr))
855 {
856 if (addr_p != NULL)
857 *addr_p = addr;
858 return 1;
859 }
860 }
861
862 return 0;
863 }
864
865 /* Try to find the target resolved function entry address of a STT_GNU_IFUNC
866 function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
867 is not NULL) and the function returns true. It returns false otherwise.
868
869 Both the elf_objfile_gnu_ifunc_cache_data hash table and
870 SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. */
871
872 static bool
873 elf_gnu_ifunc_resolve_name (const char *name, CORE_ADDR *addr_p)
874 {
875 if (elf_gnu_ifunc_resolve_by_cache (name, addr_p))
876 return true;
877
878 if (elf_gnu_ifunc_resolve_by_got (name, addr_p))
879 return true;
880
881 return false;
882 }
883
884 /* Call STT_GNU_IFUNC - a function returning addresss of a real function to
885 call. PC is theSTT_GNU_IFUNC resolving function entry. The value returned
886 is the entry point of the resolved STT_GNU_IFUNC target function to call.
887 */
888
889 static CORE_ADDR
890 elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
891 {
892 const char *name_at_pc;
893 CORE_ADDR start_at_pc, address;
894 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
895 struct value *function, *address_val;
896 CORE_ADDR hwcap = 0;
897 struct value *hwcap_val;
898
899 /* Try first any non-intrusive methods without an inferior call. */
900
901 if (find_pc_partial_function (pc, &name_at_pc, &start_at_pc, NULL)
902 && start_at_pc == pc)
903 {
904 if (elf_gnu_ifunc_resolve_name (name_at_pc, &address))
905 return address;
906 }
907 else
908 name_at_pc = NULL;
909
910 function = allocate_value (func_func_type);
911 VALUE_LVAL (function) = lval_memory;
912 set_value_address (function, pc);
913
914 /* STT_GNU_IFUNC resolver functions usually receive the HWCAP vector as
915 parameter. FUNCTION is the function entry address. ADDRESS may be a
916 function descriptor. */
917
918 target_auxv_search (current_top_target (), AT_HWCAP, &hwcap);
919 hwcap_val = value_from_longest (builtin_type (gdbarch)
920 ->builtin_unsigned_long, hwcap);
921 address_val = call_function_by_hand (function, NULL, hwcap_val);
922 address = value_as_address (address_val);
923 address = gdbarch_convert_from_func_ptr_addr (gdbarch, address, current_top_target ());
924 address = gdbarch_addr_bits_remove (gdbarch, address);
925
926 if (name_at_pc)
927 elf_gnu_ifunc_record_cache (name_at_pc, address);
928
929 return address;
930 }
931
932 /* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition. */
933
934 static void
935 elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
936 {
937 struct breakpoint *b_return;
938 struct frame_info *prev_frame = get_prev_frame (get_current_frame ());
939 struct frame_id prev_frame_id = get_stack_frame_id (prev_frame);
940 CORE_ADDR prev_pc = get_frame_pc (prev_frame);
941 int thread_id = inferior_thread ()->global_num;
942
943 gdb_assert (b->type == bp_gnu_ifunc_resolver);
944
945 for (b_return = b->related_breakpoint; b_return != b;
946 b_return = b_return->related_breakpoint)
947 {
948 gdb_assert (b_return->type == bp_gnu_ifunc_resolver_return);
949 gdb_assert (b_return->loc != NULL && b_return->loc->next == NULL);
950 gdb_assert (frame_id_p (b_return->frame_id));
951
952 if (b_return->thread == thread_id
953 && b_return->loc->requested_address == prev_pc
954 && frame_id_eq (b_return->frame_id, prev_frame_id))
955 break;
956 }
957
958 if (b_return == b)
959 {
960 /* No need to call find_pc_line for symbols resolving as this is only
961 a helper breakpointer never shown to the user. */
962
963 symtab_and_line sal;
964 sal.pspace = current_inferior ()->pspace;
965 sal.pc = prev_pc;
966 sal.section = find_pc_overlay (sal.pc);
967 sal.explicit_pc = 1;
968 b_return
969 = set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
970 prev_frame_id,
971 bp_gnu_ifunc_resolver_return).release ();
972
973 /* set_momentary_breakpoint invalidates PREV_FRAME. */
974 prev_frame = NULL;
975
976 /* Add new b_return to the ring list b->related_breakpoint. */
977 gdb_assert (b_return->related_breakpoint == b_return);
978 b_return->related_breakpoint = b->related_breakpoint;
979 b->related_breakpoint = b_return;
980 }
981 }
982
983 /* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition. */
984
985 static void
986 elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
987 {
988 thread_info *thread = inferior_thread ();
989 struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
990 struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
991 struct type *value_type = TYPE_TARGET_TYPE (func_func_type);
992 struct regcache *regcache = get_thread_regcache (thread);
993 struct value *func_func;
994 struct value *value;
995 CORE_ADDR resolved_address, resolved_pc;
996
997 gdb_assert (b->type == bp_gnu_ifunc_resolver_return);
998
999 while (b->related_breakpoint != b)
1000 {
1001 struct breakpoint *b_next = b->related_breakpoint;
1002
1003 switch (b->type)
1004 {
1005 case bp_gnu_ifunc_resolver:
1006 break;
1007 case bp_gnu_ifunc_resolver_return:
1008 delete_breakpoint (b);
1009 break;
1010 default:
1011 internal_error (__FILE__, __LINE__,
1012 _("handle_inferior_event: Invalid "
1013 "gnu-indirect-function breakpoint type %d"),
1014 (int) b->type);
1015 }
1016 b = b_next;
1017 }
1018 gdb_assert (b->type == bp_gnu_ifunc_resolver);
1019 gdb_assert (b->loc->next == NULL);
1020
1021 func_func = allocate_value (func_func_type);
1022 VALUE_LVAL (func_func) = lval_memory;
1023 set_value_address (func_func, b->loc->related_address);
1024
1025 value = allocate_value (value_type);
1026 gdbarch_return_value (gdbarch, func_func, value_type, regcache,
1027 value_contents_raw (value), NULL);
1028 resolved_address = value_as_address (value);
1029 resolved_pc = gdbarch_convert_from_func_ptr_addr (gdbarch,
1030 resolved_address,
1031 current_top_target ());
1032 resolved_pc = gdbarch_addr_bits_remove (gdbarch, resolved_pc);
1033
1034 gdb_assert (current_program_space == b->pspace || b->pspace == NULL);
1035 elf_gnu_ifunc_record_cache (event_location_to_string (b->location.get ()),
1036 resolved_pc);
1037
1038 b->type = bp_breakpoint;
1039 update_breakpoint_locations (b, current_program_space,
1040 find_function_start_sal (resolved_pc, NULL, true),
1041 {});
1042 }
1043
1044 /* A helper function for elf_symfile_read that reads the minimal
1045 symbols. */
1046
1047 static void
1048 elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags,
1049 const struct elfinfo *ei)
1050 {
1051 bfd *synth_abfd, *abfd = objfile->obfd;
1052 long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
1053 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
1054 asymbol *synthsyms;
1055
1056 if (symtab_create_debug)
1057 {
1058 fprintf_unfiltered (gdb_stdlog,
1059 "Reading minimal symbols of objfile %s ...\n",
1060 objfile_name (objfile));
1061 }
1062
1063 /* If we already have minsyms, then we can skip some work here.
1064 However, if there were stabs or mdebug sections, we go ahead and
1065 redo all the work anyway, because the psym readers for those
1066 kinds of debuginfo need extra information found here. This can
1067 go away once all types of symbols are in the per-BFD object. */
1068 if (objfile->per_bfd->minsyms_read
1069 && ei->stabsect == NULL
1070 && ei->mdebugsect == NULL
1071 && ei->ctfsect == NULL)
1072 {
1073 if (symtab_create_debug)
1074 fprintf_unfiltered (gdb_stdlog,
1075 "... minimal symbols previously read\n");
1076 return;
1077 }
1078
1079 minimal_symbol_reader reader (objfile);
1080
1081 /* Process the normal ELF symbol table first. */
1082
1083 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
1084 if (storage_needed < 0)
1085 error (_("Can't read symbols from %s: %s"),
1086 bfd_get_filename (objfile->obfd),
1087 bfd_errmsg (bfd_get_error ()));
1088
1089 if (storage_needed > 0)
1090 {
1091 /* Memory gets permanently referenced from ABFD after
1092 bfd_canonicalize_symtab so it must not get freed before ABFD gets. */
1093
1094 symbol_table = (asymbol **) bfd_alloc (abfd, storage_needed);
1095 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
1096
1097 if (symcount < 0)
1098 error (_("Can't read symbols from %s: %s"),
1099 bfd_get_filename (objfile->obfd),
1100 bfd_errmsg (bfd_get_error ()));
1101
1102 elf_symtab_read (reader, objfile, ST_REGULAR, symcount, symbol_table,
1103 false);
1104 }
1105
1106 /* Add the dynamic symbols. */
1107
1108 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
1109
1110 if (storage_needed > 0)
1111 {
1112 /* Memory gets permanently referenced from ABFD after
1113 bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
1114 It happens only in the case when elf_slurp_reloc_table sees
1115 asection->relocation NULL. Determining which section is asection is
1116 done by _bfd_elf_get_synthetic_symtab which is all a bfd
1117 implementation detail, though. */
1118
1119 dyn_symbol_table = (asymbol **) bfd_alloc (abfd, storage_needed);
1120 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
1121 dyn_symbol_table);
1122
1123 if (dynsymcount < 0)
1124 error (_("Can't read symbols from %s: %s"),
1125 bfd_get_filename (objfile->obfd),
1126 bfd_errmsg (bfd_get_error ()));
1127
1128 elf_symtab_read (reader, objfile, ST_DYNAMIC, dynsymcount,
1129 dyn_symbol_table, false);
1130
1131 elf_rel_plt_read (reader, objfile, dyn_symbol_table);
1132 }
1133
1134 /* Contrary to binutils --strip-debug/--only-keep-debug the strip command from
1135 elfutils (eu-strip) moves even the .symtab section into the .debug file.
1136
1137 bfd_get_synthetic_symtab on ppc64 for each function descriptor ELF symbol
1138 'name' creates a new BSF_SYNTHETIC ELF symbol '.name' with its code
1139 address. But with eu-strip files bfd_get_synthetic_symtab would fail to
1140 read the code address from .opd while it reads the .symtab section from
1141 a separate debug info file as the .opd section is SHT_NOBITS there.
1142
1143 With SYNTH_ABFD the .opd section will be read from the original
1144 backlinked binary where it is valid. */
1145
1146 if (objfile->separate_debug_objfile_backlink)
1147 synth_abfd = objfile->separate_debug_objfile_backlink->obfd;
1148 else
1149 synth_abfd = abfd;
1150
1151 /* Add synthetic symbols - for instance, names for any PLT entries. */
1152
1153 synthcount = bfd_get_synthetic_symtab (synth_abfd, symcount, symbol_table,
1154 dynsymcount, dyn_symbol_table,
1155 &synthsyms);
1156 if (synthcount > 0)
1157 {
1158 long i;
1159
1160 std::unique_ptr<asymbol *[]>
1161 synth_symbol_table (new asymbol *[synthcount]);
1162 for (i = 0; i < synthcount; i++)
1163 synth_symbol_table[i] = synthsyms + i;
1164 elf_symtab_read (reader, objfile, ST_SYNTHETIC, synthcount,
1165 synth_symbol_table.get (), true);
1166
1167 xfree (synthsyms);
1168 synthsyms = NULL;
1169 }
1170
1171 /* Install any minimal symbols that have been collected as the current
1172 minimal symbols for this objfile. The debug readers below this point
1173 should not generate new minimal symbols; if they do it's their
1174 responsibility to install them. "mdebug" appears to be the only one
1175 which will do this. */
1176
1177 reader.install ();
1178
1179 if (symtab_create_debug)
1180 fprintf_unfiltered (gdb_stdlog, "Done reading minimal symbols.\n");
1181 }
1182
1183 /* Scan and build partial symbols for a symbol file.
1184 We have been initialized by a call to elf_symfile_init, which
1185 currently does nothing.
1186
1187 This function only does the minimum work necessary for letting the
1188 user "name" things symbolically; it does not read the entire symtab.
1189 Instead, it reads the external and static symbols and puts them in partial
1190 symbol tables. When more extensive information is requested of a
1191 file, the corresponding partial symbol table is mutated into a full
1192 fledged symbol table by going back and reading the symbols
1193 for real.
1194
1195 We look for sections with specific names, to tell us what debug
1196 format to look for: FIXME!!!
1197
1198 elfstab_build_psymtabs() handles STABS symbols;
1199 mdebug_build_psymtabs() handles ECOFF debugging information.
1200
1201 Note that ELF files have a "minimal" symbol table, which looks a lot
1202 like a COFF symbol table, but has only the minimal information necessary
1203 for linking. We process this also, and use the information to
1204 build gdb's minimal symbol table. This gives us some minimal debugging
1205 capability even for files compiled without -g. */
1206
1207 static void
1208 elf_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
1209 {
1210 bfd *abfd = objfile->obfd;
1211 struct elfinfo ei;
1212 bool has_dwarf2 = true;
1213
1214 memset ((char *) &ei, 0, sizeof (ei));
1215 if (!(objfile->flags & OBJF_READNEVER))
1216 {
1217 for (asection *sect : gdb_bfd_sections (abfd))
1218 elf_locate_sections (sect, &ei);
1219 }
1220
1221 elf_read_minimal_symbols (objfile, symfile_flags, &ei);
1222
1223 /* ELF debugging information is inserted into the psymtab in the
1224 order of least informative first - most informative last. Since
1225 the psymtab table is searched `most recent insertion first' this
1226 increases the probability that more detailed debug information
1227 for a section is found.
1228
1229 For instance, an object file might contain both .mdebug (XCOFF)
1230 and .debug_info (DWARF2) sections then .mdebug is inserted first
1231 (searched last) and DWARF2 is inserted last (searched first). If
1232 we don't do this then the XCOFF info is found first - for code in
1233 an included file XCOFF info is useless. */
1234
1235 if (ei.mdebugsect)
1236 {
1237 const struct ecoff_debug_swap *swap;
1238
1239 /* .mdebug section, presumably holding ECOFF debugging
1240 information. */
1241 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
1242 if (swap)
1243 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
1244 }
1245 if (ei.stabsect)
1246 {
1247 asection *str_sect;
1248
1249 /* Stab sections have an associated string table that looks like
1250 a separate section. */
1251 str_sect = bfd_get_section_by_name (abfd, ".stabstr");
1252
1253 /* FIXME should probably warn about a stab section without a stabstr. */
1254 if (str_sect)
1255 elfstab_build_psymtabs (objfile,
1256 ei.stabsect,
1257 str_sect->filepos,
1258 bfd_section_size (str_sect));
1259 }
1260
1261 if (dwarf2_has_info (objfile, NULL, true))
1262 {
1263 dw_index_kind index_kind;
1264
1265 /* elf_sym_fns_gdb_index cannot handle simultaneous non-DWARF
1266 debug information present in OBJFILE. If there is such debug
1267 info present never use an index. */
1268 if (!objfile_has_partial_symbols (objfile)
1269 && dwarf2_initialize_objfile (objfile, &index_kind))
1270 {
1271 switch (index_kind)
1272 {
1273 case dw_index_kind::GDB_INDEX:
1274 objfile_set_sym_fns (objfile, &elf_sym_fns_gdb_index);
1275 break;
1276 case dw_index_kind::DEBUG_NAMES:
1277 objfile_set_sym_fns (objfile, &elf_sym_fns_debug_names);
1278 break;
1279 }
1280 }
1281 else
1282 {
1283 /* It is ok to do this even if the stabs reader made some
1284 partial symbols, because OBJF_PSYMTABS_READ has not been
1285 set, and so our lazy reader function will still be called
1286 when needed. */
1287 objfile_set_sym_fns (objfile, &elf_sym_fns_lazy_psyms);
1288 }
1289 }
1290 /* If the file has its own symbol tables it has no separate debug
1291 info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
1292 SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
1293 `.note.gnu.build-id'.
1294
1295 .gnu_debugdata is !objfile_has_partial_symbols because it contains only
1296 .symtab, not .debug_* section. But if we already added .gnu_debugdata as
1297 an objfile via find_separate_debug_file_in_section there was no separate
1298 debug info available. Therefore do not attempt to search for another one,
1299 objfile->separate_debug_objfile->separate_debug_objfile GDB guarantees to
1300 be NULL and we would possibly violate it. */
1301
1302 else if (!objfile_has_partial_symbols (objfile)
1303 && objfile->separate_debug_objfile == NULL
1304 && objfile->separate_debug_objfile_backlink == NULL)
1305 {
1306 std::string debugfile = find_separate_debug_file_by_buildid (objfile);
1307
1308 if (debugfile.empty ())
1309 debugfile = find_separate_debug_file_by_debuglink (objfile);
1310
1311 if (!debugfile.empty ())
1312 {
1313 gdb_bfd_ref_ptr debug_bfd (symfile_bfd_open (debugfile.c_str ()));
1314
1315 symbol_file_add_separate (debug_bfd.get (), debugfile.c_str (),
1316 symfile_flags, objfile);
1317 }
1318 else
1319 {
1320 has_dwarf2 = false;
1321 const struct bfd_build_id *build_id = build_id_bfd_get (objfile->obfd);
1322
1323 if (build_id != nullptr)
1324 {
1325 gdb::unique_xmalloc_ptr<char> symfile_path;
1326 scoped_fd fd (debuginfod_debuginfo_query (build_id->data,
1327 build_id->size,
1328 objfile->original_name,
1329 &symfile_path));
1330
1331 if (fd.get () >= 0)
1332 {
1333 /* File successfully retrieved from server. */
1334 gdb_bfd_ref_ptr debug_bfd (symfile_bfd_open (symfile_path.get ()));
1335
1336 if (debug_bfd == nullptr)
1337 warning (_("File \"%s\" from debuginfod cannot be opened as bfd"),
1338 objfile->original_name);
1339 else if (build_id_verify (debug_bfd.get (), build_id->size, build_id->data))
1340 {
1341 symbol_file_add_separate (debug_bfd.get (), symfile_path.get (),
1342 symfile_flags, objfile);
1343 has_dwarf2 = true;
1344 }
1345 }
1346 }
1347 }
1348 }
1349
1350 /* Read the CTF section only if there is no DWARF info. */
1351 if (!has_dwarf2 && ei.ctfsect)
1352 {
1353 elfctf_build_psymtabs (objfile);
1354 }
1355 }
1356
1357 /* Callback to lazily read psymtabs. */
1358
1359 static void
1360 read_psyms (struct objfile *objfile)
1361 {
1362 if (dwarf2_has_info (objfile, NULL))
1363 dwarf2_build_psymtabs (objfile);
1364 }
1365
1366 /* Initialize anything that needs initializing when a completely new symbol
1367 file is specified (not just adding some symbols from another file, e.g. a
1368 shared library). */
1369
1370 static void
1371 elf_new_init (struct objfile *ignore)
1372 {
1373 }
1374
1375 /* Perform any local cleanups required when we are done with a particular
1376 objfile. I.E, we are in the process of discarding all symbol information
1377 for an objfile, freeing up all memory held for it, and unlinking the
1378 objfile struct from the global list of known objfiles. */
1379
1380 static void
1381 elf_symfile_finish (struct objfile *objfile)
1382 {
1383 }
1384
1385 /* ELF specific initialization routine for reading symbols. */
1386
1387 static void
1388 elf_symfile_init (struct objfile *objfile)
1389 {
1390 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
1391 find this causes a significant slowdown in gdb then we could
1392 set it in the debug symbol readers only when necessary. */
1393 objfile->flags |= OBJF_REORDERED;
1394 }
1395
1396 /* Implementation of `sym_get_probes', as documented in symfile.h. */
1397
1398 static const elfread_data &
1399 elf_get_probes (struct objfile *objfile)
1400 {
1401 elfread_data *probes_per_bfd = probe_key.get (objfile->obfd);
1402
1403 if (probes_per_bfd == NULL)
1404 {
1405 probes_per_bfd = probe_key.emplace (objfile->obfd);
1406
1407 /* Here we try to gather information about all types of probes from the
1408 objfile. */
1409 for (const static_probe_ops *ops : all_static_probe_ops)
1410 ops->get_probes (probes_per_bfd, objfile);
1411 }
1412
1413 return *probes_per_bfd;
1414 }
1415
1416 \f
1417
1418 /* Implementation `sym_probe_fns', as documented in symfile.h. */
1419
1420 static const struct sym_probe_fns elf_probe_fns =
1421 {
1422 elf_get_probes, /* sym_get_probes */
1423 };
1424
1425 /* Register that we are able to handle ELF object file formats. */
1426
1427 static const struct sym_fns elf_sym_fns =
1428 {
1429 elf_new_init, /* init anything gbl to entire symtab */
1430 elf_symfile_init, /* read initial info, setup for sym_read() */
1431 elf_symfile_read, /* read a symbol file into symtab */
1432 NULL, /* sym_read_psymbols */
1433 elf_symfile_finish, /* finished with file, cleanup */
1434 default_symfile_offsets, /* Translate ext. to int. relocation */
1435 elf_symfile_segments, /* Get segment information from a file. */
1436 NULL,
1437 default_symfile_relocate, /* Relocate a debug section. */
1438 &elf_probe_fns, /* sym_probe_fns */
1439 &psym_functions
1440 };
1441
1442 /* The same as elf_sym_fns, but not registered and lazily reads
1443 psymbols. */
1444
1445 const struct sym_fns elf_sym_fns_lazy_psyms =
1446 {
1447 elf_new_init, /* init anything gbl to entire symtab */
1448 elf_symfile_init, /* read initial info, setup for sym_read() */
1449 elf_symfile_read, /* read a symbol file into symtab */
1450 read_psyms, /* sym_read_psymbols */
1451 elf_symfile_finish, /* finished with file, cleanup */
1452 default_symfile_offsets, /* Translate ext. to int. relocation */
1453 elf_symfile_segments, /* Get segment information from a file. */
1454 NULL,
1455 default_symfile_relocate, /* Relocate a debug section. */
1456 &elf_probe_fns, /* sym_probe_fns */
1457 &psym_functions
1458 };
1459
1460 /* The same as elf_sym_fns, but not registered and uses the
1461 DWARF-specific GNU index rather than psymtab. */
1462 const struct sym_fns elf_sym_fns_gdb_index =
1463 {
1464 elf_new_init, /* init anything gbl to entire symab */
1465 elf_symfile_init, /* read initial info, setup for sym_red() */
1466 elf_symfile_read, /* read a symbol file into symtab */
1467 NULL, /* sym_read_psymbols */
1468 elf_symfile_finish, /* finished with file, cleanup */
1469 default_symfile_offsets, /* Translate ext. to int. relocation */
1470 elf_symfile_segments, /* Get segment information from a file. */
1471 NULL,
1472 default_symfile_relocate, /* Relocate a debug section. */
1473 &elf_probe_fns, /* sym_probe_fns */
1474 &dwarf2_gdb_index_functions
1475 };
1476
1477 /* The same as elf_sym_fns, but not registered and uses the
1478 DWARF-specific .debug_names index rather than psymtab. */
1479 const struct sym_fns elf_sym_fns_debug_names =
1480 {
1481 elf_new_init, /* init anything gbl to entire symab */
1482 elf_symfile_init, /* read initial info, setup for sym_red() */
1483 elf_symfile_read, /* read a symbol file into symtab */
1484 NULL, /* sym_read_psymbols */
1485 elf_symfile_finish, /* finished with file, cleanup */
1486 default_symfile_offsets, /* Translate ext. to int. relocation */
1487 elf_symfile_segments, /* Get segment information from a file. */
1488 NULL,
1489 default_symfile_relocate, /* Relocate a debug section. */
1490 &elf_probe_fns, /* sym_probe_fns */
1491 &dwarf2_debug_names_functions
1492 };
1493
1494 /* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p. */
1495
1496 static const struct gnu_ifunc_fns elf_gnu_ifunc_fns =
1497 {
1498 elf_gnu_ifunc_resolve_addr,
1499 elf_gnu_ifunc_resolve_name,
1500 elf_gnu_ifunc_resolver_stop,
1501 elf_gnu_ifunc_resolver_return_stop
1502 };
1503
1504 void _initialize_elfread ();
1505 void
1506 _initialize_elfread ()
1507 {
1508 add_symtab_fns (bfd_target_elf_flavour, &elf_sym_fns);
1509
1510 gnu_ifunc_fns_p = &elf_gnu_ifunc_fns;
1511 }
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