Commit | Line | Data |
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c906108c | 1 | /* Read ELF (Executable and Linking Format) object files for GDB. |
1bac305b | 2 | |
6aba47ca DJ |
3 | Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, |
4 | 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. | |
1bac305b | 5 | |
c906108c SS |
6 | Written by Fred Fish at Cygnus Support. |
7 | ||
c5aa993b | 8 | This file is part of GDB. |
c906108c | 9 | |
c5aa993b JM |
10 | This program is free software; you can redistribute it and/or modify |
11 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 12 | the Free Software Foundation; either version 3 of the License, or |
c5aa993b | 13 | (at your option) any later version. |
c906108c | 14 | |
c5aa993b JM |
15 | This program is distributed in the hope that it will be useful, |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
c906108c | 19 | |
c5aa993b | 20 | You should have received a copy of the GNU General Public License |
a9762ec7 | 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c906108c SS |
22 | |
23 | #include "defs.h" | |
24 | #include "bfd.h" | |
25 | #include "gdb_string.h" | |
26 | #include "elf-bfd.h" | |
31d99776 DJ |
27 | #include "elf/common.h" |
28 | #include "elf/internal.h" | |
c906108c SS |
29 | #include "elf/mips.h" |
30 | #include "symtab.h" | |
31 | #include "symfile.h" | |
32 | #include "objfiles.h" | |
33 | #include "buildsym.h" | |
34 | #include "stabsread.h" | |
35 | #include "gdb-stabs.h" | |
36 | #include "complaints.h" | |
37 | #include "demangle.h" | |
38 | ||
a14ed312 | 39 | extern void _initialize_elfread (void); |
392a587b | 40 | |
c906108c | 41 | /* The struct elfinfo is available only during ELF symbol table and |
6426a772 | 42 | psymtab reading. It is destroyed at the completion of psymtab-reading. |
c906108c SS |
43 | It's local to elf_symfile_read. */ |
44 | ||
c5aa993b JM |
45 | struct elfinfo |
46 | { | |
c5aa993b JM |
47 | asection *stabsect; /* Section pointer for .stab section */ |
48 | asection *stabindexsect; /* Section pointer for .stab.index section */ | |
49 | asection *mdebugsect; /* Section pointer for .mdebug section */ | |
50 | }; | |
c906108c | 51 | |
12b9c64f | 52 | static void free_elfinfo (void *); |
c906108c | 53 | |
31d99776 DJ |
54 | /* Locate the segments in ABFD. */ |
55 | ||
56 | static struct symfile_segment_data * | |
57 | elf_symfile_segments (bfd *abfd) | |
58 | { | |
59 | Elf_Internal_Phdr *phdrs, **segments; | |
60 | long phdrs_size; | |
61 | int num_phdrs, num_segments, num_sections, i; | |
62 | asection *sect; | |
63 | struct symfile_segment_data *data; | |
64 | ||
65 | phdrs_size = bfd_get_elf_phdr_upper_bound (abfd); | |
66 | if (phdrs_size == -1) | |
67 | return NULL; | |
68 | ||
69 | phdrs = alloca (phdrs_size); | |
70 | num_phdrs = bfd_get_elf_phdrs (abfd, phdrs); | |
71 | if (num_phdrs == -1) | |
72 | return NULL; | |
73 | ||
74 | num_segments = 0; | |
75 | segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs); | |
76 | for (i = 0; i < num_phdrs; i++) | |
77 | if (phdrs[i].p_type == PT_LOAD) | |
78 | segments[num_segments++] = &phdrs[i]; | |
79 | ||
80 | if (num_segments == 0) | |
81 | return NULL; | |
82 | ||
83 | data = XZALLOC (struct symfile_segment_data); | |
84 | data->num_segments = num_segments; | |
85 | data->segment_bases = XCALLOC (num_segments, CORE_ADDR); | |
86 | data->segment_sizes = XCALLOC (num_segments, CORE_ADDR); | |
87 | ||
88 | for (i = 0; i < num_segments; i++) | |
89 | { | |
90 | data->segment_bases[i] = segments[i]->p_vaddr; | |
91 | data->segment_sizes[i] = segments[i]->p_memsz; | |
92 | } | |
93 | ||
94 | num_sections = bfd_count_sections (abfd); | |
95 | data->segment_info = XCALLOC (num_sections, int); | |
96 | ||
97 | for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next) | |
98 | { | |
99 | int j; | |
100 | CORE_ADDR vma; | |
101 | ||
102 | if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) | |
103 | continue; | |
104 | ||
105 | vma = bfd_get_section_vma (abfd, sect); | |
106 | ||
107 | for (j = 0; j < num_segments; j++) | |
108 | if (segments[j]->p_memsz > 0 | |
109 | && vma >= segments[j]->p_vaddr | |
110 | && vma < segments[j]->p_vaddr + segments[j]->p_memsz) | |
111 | { | |
112 | data->segment_info[i] = j + 1; | |
113 | break; | |
114 | } | |
115 | ||
116 | if (bfd_get_section_size (sect) > 0 && j == num_segments) | |
117 | warning (_("Loadable segment \"%s\" outside of ELF segments"), | |
118 | bfd_section_name (abfd, sect)); | |
119 | } | |
120 | ||
121 | return data; | |
122 | } | |
123 | ||
c906108c SS |
124 | /* We are called once per section from elf_symfile_read. We |
125 | need to examine each section we are passed, check to see | |
126 | if it is something we are interested in processing, and | |
127 | if so, stash away some access information for the section. | |
128 | ||
129 | For now we recognize the dwarf debug information sections and | |
130 | line number sections from matching their section names. The | |
131 | ELF definition is no real help here since it has no direct | |
132 | knowledge of DWARF (by design, so any debugging format can be | |
133 | used). | |
134 | ||
135 | We also recognize the ".stab" sections used by the Sun compilers | |
136 | released with Solaris 2. | |
137 | ||
138 | FIXME: The section names should not be hardwired strings (what | |
139 | should they be? I don't think most object file formats have enough | |
140 | section flags to specify what kind of debug section it is | |
141 | -kingdon). */ | |
142 | ||
143 | static void | |
12b9c64f | 144 | elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip) |
c906108c | 145 | { |
52f0bd74 | 146 | struct elfinfo *ei; |
c906108c SS |
147 | |
148 | ei = (struct elfinfo *) eip; | |
7ce59000 | 149 | if (strcmp (sectp->name, ".stab") == 0) |
c906108c | 150 | { |
c5aa993b | 151 | ei->stabsect = sectp; |
c906108c | 152 | } |
6314a349 | 153 | else if (strcmp (sectp->name, ".stab.index") == 0) |
c906108c | 154 | { |
c5aa993b | 155 | ei->stabindexsect = sectp; |
c906108c | 156 | } |
6314a349 | 157 | else if (strcmp (sectp->name, ".mdebug") == 0) |
c906108c | 158 | { |
c5aa993b | 159 | ei->mdebugsect = sectp; |
c906108c SS |
160 | } |
161 | } | |
162 | ||
c906108c | 163 | static struct minimal_symbol * |
f594e5e9 MC |
164 | record_minimal_symbol (char *name, CORE_ADDR address, |
165 | enum minimal_symbol_type ms_type, | |
166 | asection *bfd_section, struct objfile *objfile) | |
c906108c | 167 | { |
bbeae047 | 168 | if (ms_type == mst_text || ms_type == mst_file_text) |
260edbc2 | 169 | address = gdbarch_smash_text_address (current_gdbarch, address); |
c906108c SS |
170 | |
171 | return prim_record_minimal_symbol_and_info | |
f594e5e9 | 172 | (name, address, ms_type, NULL, bfd_section->index, bfd_section, objfile); |
c906108c SS |
173 | } |
174 | ||
175 | /* | |
176 | ||
c5aa993b | 177 | LOCAL FUNCTION |
c906108c | 178 | |
c5aa993b | 179 | elf_symtab_read -- read the symbol table of an ELF file |
c906108c | 180 | |
c5aa993b | 181 | SYNOPSIS |
c906108c | 182 | |
62553543 EZ |
183 | void elf_symtab_read (struct objfile *objfile, int dynamic, |
184 | long number_of_symbols, asymbol **symbol_table) | |
c906108c | 185 | |
c5aa993b | 186 | DESCRIPTION |
c906108c | 187 | |
62553543 EZ |
188 | Given an objfile, a symbol table, and a flag indicating whether the |
189 | symbol table contains dynamic symbols, add all the global function | |
190 | and data symbols to the minimal symbol table. | |
c906108c | 191 | |
c5aa993b JM |
192 | In stabs-in-ELF, as implemented by Sun, there are some local symbols |
193 | defined in the ELF symbol table, which can be used to locate | |
194 | the beginnings of sections from each ".o" file that was linked to | |
195 | form the executable objfile. We gather any such info and record it | |
196 | in data structures hung off the objfile's private data. | |
c906108c | 197 | |
c5aa993b | 198 | */ |
c906108c SS |
199 | |
200 | static void | |
62553543 EZ |
201 | elf_symtab_read (struct objfile *objfile, int dynamic, |
202 | long number_of_symbols, asymbol **symbol_table) | |
c906108c SS |
203 | { |
204 | long storage_needed; | |
205 | asymbol *sym; | |
c906108c | 206 | long i; |
c906108c | 207 | CORE_ADDR symaddr; |
d4f3574e | 208 | CORE_ADDR offset; |
c906108c SS |
209 | enum minimal_symbol_type ms_type; |
210 | /* If sectinfo is nonNULL, it contains section info that should end up | |
211 | filed in the objfile. */ | |
212 | struct stab_section_info *sectinfo = NULL; | |
213 | /* If filesym is nonzero, it points to a file symbol, but we haven't | |
214 | seen any section info for it yet. */ | |
215 | asymbol *filesym = 0; | |
4a146b47 EZ |
216 | /* Name of filesym, as saved on the objfile_obstack. */ |
217 | char *filesymname = obsavestring ("", 0, &objfile->objfile_obstack); | |
0a6ddd08 | 218 | struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; |
d4f3574e | 219 | int stripped = (bfd_get_symcount (objfile->obfd) == 0); |
c5aa993b | 220 | |
0cc7b392 | 221 | for (i = 0; i < number_of_symbols; i++) |
c906108c | 222 | { |
0cc7b392 DJ |
223 | sym = symbol_table[i]; |
224 | if (sym->name == NULL || *sym->name == '\0') | |
c906108c | 225 | { |
0cc7b392 DJ |
226 | /* Skip names that don't exist (shouldn't happen), or names |
227 | that are null strings (may happen). */ | |
228 | continue; | |
229 | } | |
c906108c | 230 | |
74763737 DJ |
231 | /* Skip "special" symbols, e.g. ARM mapping symbols. These are |
232 | symbols which do not correspond to objects in the symbol table, | |
233 | but have some other target-specific meaning. */ | |
234 | if (bfd_is_target_special_symbol (objfile->obfd, sym)) | |
235 | continue; | |
236 | ||
0cc7b392 DJ |
237 | offset = ANOFFSET (objfile->section_offsets, sym->section->index); |
238 | if (dynamic | |
239 | && sym->section == &bfd_und_section | |
240 | && (sym->flags & BSF_FUNCTION)) | |
241 | { | |
242 | struct minimal_symbol *msym; | |
02c75f72 UW |
243 | bfd *abfd = objfile->obfd; |
244 | asection *sect; | |
0cc7b392 DJ |
245 | |
246 | /* Symbol is a reference to a function defined in | |
247 | a shared library. | |
248 | If its value is non zero then it is usually the address | |
249 | of the corresponding entry in the procedure linkage table, | |
250 | plus the desired section offset. | |
251 | If its value is zero then the dynamic linker has to resolve | |
252 | the symbol. We are unable to find any meaningful address | |
253 | for this symbol in the executable file, so we skip it. */ | |
254 | symaddr = sym->value; | |
255 | if (symaddr == 0) | |
256 | continue; | |
02c75f72 UW |
257 | |
258 | /* sym->section is the undefined section. However, we want to | |
259 | record the section where the PLT stub resides with the | |
260 | minimal symbol. Search the section table for the one that | |
261 | covers the stub's address. */ | |
262 | for (sect = abfd->sections; sect != NULL; sect = sect->next) | |
263 | { | |
264 | if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0) | |
265 | continue; | |
266 | ||
267 | if (symaddr >= bfd_get_section_vma (abfd, sect) | |
268 | && symaddr < bfd_get_section_vma (abfd, sect) | |
269 | + bfd_get_section_size (sect)) | |
270 | break; | |
271 | } | |
272 | if (!sect) | |
273 | continue; | |
274 | ||
275 | symaddr += ANOFFSET (objfile->section_offsets, sect->index); | |
276 | ||
0cc7b392 | 277 | msym = record_minimal_symbol |
02c75f72 | 278 | ((char *) sym->name, symaddr, mst_solib_trampoline, sect, objfile); |
0cc7b392 DJ |
279 | if (msym != NULL) |
280 | msym->filename = filesymname; | |
0cc7b392 DJ |
281 | continue; |
282 | } | |
c906108c | 283 | |
0cc7b392 DJ |
284 | /* If it is a nonstripped executable, do not enter dynamic |
285 | symbols, as the dynamic symbol table is usually a subset | |
286 | of the main symbol table. */ | |
287 | if (dynamic && !stripped) | |
288 | continue; | |
289 | if (sym->flags & BSF_FILE) | |
290 | { | |
291 | /* STT_FILE debugging symbol that helps stabs-in-elf debugging. | |
292 | Chain any old one onto the objfile; remember new sym. */ | |
293 | if (sectinfo != NULL) | |
c906108c | 294 | { |
0cc7b392 DJ |
295 | sectinfo->next = dbx->stab_section_info; |
296 | dbx->stab_section_info = sectinfo; | |
297 | sectinfo = NULL; | |
298 | } | |
299 | filesym = sym; | |
0cc7b392 DJ |
300 | filesymname = |
301 | obsavestring ((char *) filesym->name, strlen (filesym->name), | |
302 | &objfile->objfile_obstack); | |
0cc7b392 DJ |
303 | } |
304 | else if (sym->flags & BSF_SECTION_SYM) | |
305 | continue; | |
306 | else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK)) | |
307 | { | |
308 | struct minimal_symbol *msym; | |
309 | ||
310 | /* Select global/local/weak symbols. Note that bfd puts abs | |
311 | symbols in their own section, so all symbols we are | |
312 | interested in will have a section. */ | |
313 | /* Bfd symbols are section relative. */ | |
314 | symaddr = sym->value + sym->section->vma; | |
315 | /* Relocate all non-absolute symbols by the section offset. */ | |
316 | if (sym->section != &bfd_abs_section) | |
317 | { | |
318 | symaddr += offset; | |
c906108c | 319 | } |
0cc7b392 DJ |
320 | /* For non-absolute symbols, use the type of the section |
321 | they are relative to, to intuit text/data. Bfd provides | |
322 | no way of figuring this out for absolute symbols. */ | |
323 | if (sym->section == &bfd_abs_section) | |
c906108c | 324 | { |
0cc7b392 DJ |
325 | /* This is a hack to get the minimal symbol type |
326 | right for Irix 5, which has absolute addresses | |
327 | with special section indices for dynamic symbols. */ | |
328 | unsigned short shndx = | |
329 | ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx; | |
330 | ||
331 | switch (shndx) | |
c906108c | 332 | { |
0cc7b392 DJ |
333 | case SHN_MIPS_TEXT: |
334 | ms_type = mst_text; | |
335 | break; | |
336 | case SHN_MIPS_DATA: | |
337 | ms_type = mst_data; | |
338 | break; | |
339 | case SHN_MIPS_ACOMMON: | |
340 | ms_type = mst_bss; | |
341 | break; | |
342 | default: | |
343 | ms_type = mst_abs; | |
344 | } | |
345 | ||
346 | /* If it is an Irix dynamic symbol, skip section name | |
347 | symbols, relocate all others by section offset. */ | |
348 | if (ms_type != mst_abs) | |
349 | { | |
350 | if (sym->name[0] == '.') | |
351 | continue; | |
d4f3574e | 352 | symaddr += offset; |
c906108c | 353 | } |
0cc7b392 DJ |
354 | } |
355 | else if (sym->section->flags & SEC_CODE) | |
356 | { | |
08232497 | 357 | if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) |
c906108c | 358 | { |
0cc7b392 DJ |
359 | ms_type = mst_text; |
360 | } | |
361 | else if ((sym->name[0] == '.' && sym->name[1] == 'L') | |
362 | || ((sym->flags & BSF_LOCAL) | |
363 | && sym->name[0] == '$' | |
364 | && sym->name[1] == 'L')) | |
365 | /* Looks like a compiler-generated label. Skip | |
366 | it. The assembler should be skipping these (to | |
367 | keep executables small), but apparently with | |
368 | gcc on the (deleted) delta m88k SVR4, it loses. | |
369 | So to have us check too should be harmless (but | |
370 | I encourage people to fix this in the assembler | |
371 | instead of adding checks here). */ | |
372 | continue; | |
373 | else | |
374 | { | |
375 | ms_type = mst_file_text; | |
c906108c | 376 | } |
0cc7b392 DJ |
377 | } |
378 | else if (sym->section->flags & SEC_ALLOC) | |
379 | { | |
380 | if (sym->flags & (BSF_GLOBAL | BSF_WEAK)) | |
c906108c | 381 | { |
0cc7b392 | 382 | if (sym->section->flags & SEC_LOAD) |
c906108c | 383 | { |
0cc7b392 | 384 | ms_type = mst_data; |
c906108c | 385 | } |
c906108c SS |
386 | else |
387 | { | |
0cc7b392 | 388 | ms_type = mst_bss; |
c906108c SS |
389 | } |
390 | } | |
0cc7b392 | 391 | else if (sym->flags & BSF_LOCAL) |
c906108c | 392 | { |
0cc7b392 DJ |
393 | /* Named Local variable in a Data section. |
394 | Check its name for stabs-in-elf. */ | |
395 | int special_local_sect; | |
396 | if (strcmp ("Bbss.bss", sym->name) == 0) | |
397 | special_local_sect = SECT_OFF_BSS (objfile); | |
398 | else if (strcmp ("Ddata.data", sym->name) == 0) | |
399 | special_local_sect = SECT_OFF_DATA (objfile); | |
400 | else if (strcmp ("Drodata.rodata", sym->name) == 0) | |
401 | special_local_sect = SECT_OFF_RODATA (objfile); | |
402 | else | |
403 | special_local_sect = -1; | |
404 | if (special_local_sect >= 0) | |
c906108c | 405 | { |
0cc7b392 DJ |
406 | /* Found a special local symbol. Allocate a |
407 | sectinfo, if needed, and fill it in. */ | |
408 | if (sectinfo == NULL) | |
c906108c | 409 | { |
0cc7b392 DJ |
410 | int max_index; |
411 | size_t size; | |
412 | ||
413 | max_index | |
414 | = max (SECT_OFF_BSS (objfile), | |
415 | max (SECT_OFF_DATA (objfile), | |
416 | SECT_OFF_RODATA (objfile))); | |
417 | ||
418 | /* max_index is the largest index we'll | |
419 | use into this array, so we must | |
420 | allocate max_index+1 elements for it. | |
421 | However, 'struct stab_section_info' | |
422 | already includes one element, so we | |
423 | need to allocate max_index aadditional | |
424 | elements. */ | |
425 | size = (sizeof (struct stab_section_info) | |
426 | + (sizeof (CORE_ADDR) | |
427 | * max_index)); | |
428 | sectinfo = (struct stab_section_info *) | |
429 | xmalloc (size); | |
430 | memset (sectinfo, 0, size); | |
431 | sectinfo->num_sections = max_index; | |
432 | if (filesym == NULL) | |
c906108c | 433 | { |
0cc7b392 DJ |
434 | complaint (&symfile_complaints, |
435 | _("elf/stab section information %s without a preceding file symbol"), | |
436 | sym->name); | |
437 | } | |
438 | else | |
439 | { | |
440 | sectinfo->filename = | |
441 | (char *) filesym->name; | |
c906108c | 442 | } |
c906108c | 443 | } |
0cc7b392 DJ |
444 | if (sectinfo->sections[special_local_sect] != 0) |
445 | complaint (&symfile_complaints, | |
446 | _("duplicated elf/stab section information for %s"), | |
447 | sectinfo->filename); | |
448 | /* BFD symbols are section relative. */ | |
449 | symaddr = sym->value + sym->section->vma; | |
450 | /* Relocate non-absolute symbols by the | |
451 | section offset. */ | |
452 | if (sym->section != &bfd_abs_section) | |
453 | symaddr += offset; | |
454 | sectinfo->sections[special_local_sect] = symaddr; | |
455 | /* The special local symbols don't go in the | |
456 | minimal symbol table, so ignore this one. */ | |
457 | continue; | |
458 | } | |
459 | /* Not a special stabs-in-elf symbol, do regular | |
460 | symbol processing. */ | |
461 | if (sym->section->flags & SEC_LOAD) | |
462 | { | |
463 | ms_type = mst_file_data; | |
c906108c SS |
464 | } |
465 | else | |
466 | { | |
0cc7b392 | 467 | ms_type = mst_file_bss; |
c906108c SS |
468 | } |
469 | } | |
470 | else | |
471 | { | |
0cc7b392 | 472 | ms_type = mst_unknown; |
c906108c | 473 | } |
0cc7b392 DJ |
474 | } |
475 | else | |
476 | { | |
477 | /* FIXME: Solaris2 shared libraries include lots of | |
478 | odd "absolute" and "undefined" symbols, that play | |
479 | hob with actions like finding what function the PC | |
480 | is in. Ignore them if they aren't text, data, or bss. */ | |
481 | /* ms_type = mst_unknown; */ | |
482 | continue; /* Skip this symbol. */ | |
483 | } | |
484 | msym = record_minimal_symbol | |
485 | ((char *) sym->name, symaddr, | |
486 | ms_type, sym->section, objfile); | |
487 | if (msym) | |
488 | { | |
489 | /* Pass symbol size field in via BFD. FIXME!!! */ | |
490 | unsigned long size = ((elf_symbol_type *) sym)->internal_elf_sym.st_size; | |
491 | MSYMBOL_SIZE(msym) = size; | |
492 | } | |
0cc7b392 DJ |
493 | if (msym != NULL) |
494 | msym->filename = filesymname; | |
95f1da47 | 495 | gdbarch_elf_make_msymbol_special (current_gdbarch, sym, msym); |
c906108c | 496 | } |
c906108c SS |
497 | } |
498 | } | |
499 | ||
500 | /* Scan and build partial symbols for a symbol file. | |
501 | We have been initialized by a call to elf_symfile_init, which | |
502 | currently does nothing. | |
503 | ||
504 | SECTION_OFFSETS is a set of offsets to apply to relocate the symbols | |
505 | in each section. We simplify it down to a single offset for all | |
506 | symbols. FIXME. | |
507 | ||
508 | MAINLINE is true if we are reading the main symbol | |
509 | table (as opposed to a shared lib or dynamically loaded file). | |
510 | ||
511 | This function only does the minimum work necessary for letting the | |
512 | user "name" things symbolically; it does not read the entire symtab. | |
513 | Instead, it reads the external and static symbols and puts them in partial | |
514 | symbol tables. When more extensive information is requested of a | |
515 | file, the corresponding partial symbol table is mutated into a full | |
516 | fledged symbol table by going back and reading the symbols | |
517 | for real. | |
518 | ||
519 | We look for sections with specific names, to tell us what debug | |
520 | format to look for: FIXME!!! | |
521 | ||
c906108c SS |
522 | elfstab_build_psymtabs() handles STABS symbols; |
523 | mdebug_build_psymtabs() handles ECOFF debugging information. | |
524 | ||
525 | Note that ELF files have a "minimal" symbol table, which looks a lot | |
526 | like a COFF symbol table, but has only the minimal information necessary | |
527 | for linking. We process this also, and use the information to | |
528 | build gdb's minimal symbol table. This gives us some minimal debugging | |
529 | capability even for files compiled without -g. */ | |
530 | ||
531 | static void | |
fba45db2 | 532 | elf_symfile_read (struct objfile *objfile, int mainline) |
c906108c SS |
533 | { |
534 | bfd *abfd = objfile->obfd; | |
535 | struct elfinfo ei; | |
536 | struct cleanup *back_to; | |
537 | CORE_ADDR offset; | |
62553543 EZ |
538 | long symcount = 0, dynsymcount = 0, synthcount, storage_needed; |
539 | asymbol **symbol_table = NULL, **dyn_symbol_table = NULL; | |
540 | asymbol *synthsyms; | |
c906108c SS |
541 | |
542 | init_minimal_symbol_collection (); | |
56e290f4 | 543 | back_to = make_cleanup_discard_minimal_symbols (); |
c906108c SS |
544 | |
545 | memset ((char *) &ei, 0, sizeof (ei)); | |
546 | ||
547 | /* Allocate struct to keep track of the symfile */ | |
0a6ddd08 | 548 | objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *) |
7936743b | 549 | xmalloc (sizeof (struct dbx_symfile_info)); |
0a6ddd08 | 550 | memset ((char *) objfile->deprecated_sym_stab_info, 0, sizeof (struct dbx_symfile_info)); |
12b9c64f | 551 | make_cleanup (free_elfinfo, (void *) objfile); |
c906108c SS |
552 | |
553 | /* Process the normal ELF symbol table first. This may write some | |
0a6ddd08 | 554 | chain of info into the dbx_symfile_info in objfile->deprecated_sym_stab_info, |
c906108c SS |
555 | which can later be used by elfstab_offset_sections. */ |
556 | ||
62553543 EZ |
557 | storage_needed = bfd_get_symtab_upper_bound (objfile->obfd); |
558 | if (storage_needed < 0) | |
559 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), | |
560 | bfd_errmsg (bfd_get_error ())); | |
561 | ||
562 | if (storage_needed > 0) | |
563 | { | |
564 | symbol_table = (asymbol **) xmalloc (storage_needed); | |
565 | make_cleanup (xfree, symbol_table); | |
566 | symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table); | |
567 | ||
568 | if (symcount < 0) | |
569 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), | |
570 | bfd_errmsg (bfd_get_error ())); | |
571 | ||
572 | elf_symtab_read (objfile, 0, symcount, symbol_table); | |
573 | } | |
c906108c SS |
574 | |
575 | /* Add the dynamic symbols. */ | |
576 | ||
62553543 EZ |
577 | storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd); |
578 | ||
579 | if (storage_needed > 0) | |
580 | { | |
581 | dyn_symbol_table = (asymbol **) xmalloc (storage_needed); | |
582 | make_cleanup (xfree, dyn_symbol_table); | |
583 | dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd, | |
584 | dyn_symbol_table); | |
585 | ||
586 | if (dynsymcount < 0) | |
587 | error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd), | |
588 | bfd_errmsg (bfd_get_error ())); | |
589 | ||
590 | elf_symtab_read (objfile, 1, dynsymcount, dyn_symbol_table); | |
591 | } | |
592 | ||
593 | /* Add synthetic symbols - for instance, names for any PLT entries. */ | |
594 | ||
595 | synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table, | |
596 | dynsymcount, dyn_symbol_table, | |
597 | &synthsyms); | |
598 | if (synthcount > 0) | |
599 | { | |
600 | asymbol **synth_symbol_table; | |
601 | long i; | |
602 | ||
603 | make_cleanup (xfree, synthsyms); | |
604 | synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount); | |
605 | for (i = 0; i < synthcount; i++) | |
9f20e3da | 606 | synth_symbol_table[i] = synthsyms + i; |
62553543 EZ |
607 | make_cleanup (xfree, synth_symbol_table); |
608 | elf_symtab_read (objfile, 0, synthcount, synth_symbol_table); | |
609 | } | |
c906108c | 610 | |
7134143f DJ |
611 | /* Install any minimal symbols that have been collected as the current |
612 | minimal symbols for this objfile. The debug readers below this point | |
613 | should not generate new minimal symbols; if they do it's their | |
614 | responsibility to install them. "mdebug" appears to be the only one | |
615 | which will do this. */ | |
616 | ||
617 | install_minimal_symbols (objfile); | |
618 | do_cleanups (back_to); | |
619 | ||
c906108c SS |
620 | /* Now process debugging information, which is contained in |
621 | special ELF sections. */ | |
622 | ||
623 | /* If we are reinitializing, or if we have never loaded syms yet, | |
624 | set table to empty. MAINLINE is cleared so that *_read_psymtab | |
625 | functions do not all also re-initialize the psymbol table. */ | |
626 | if (mainline) | |
627 | { | |
628 | init_psymbol_list (objfile, 0); | |
629 | mainline = 0; | |
630 | } | |
631 | ||
632 | /* We first have to find them... */ | |
12b9c64f | 633 | bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei); |
c906108c SS |
634 | |
635 | /* ELF debugging information is inserted into the psymtab in the | |
636 | order of least informative first - most informative last. Since | |
637 | the psymtab table is searched `most recent insertion first' this | |
638 | increases the probability that more detailed debug information | |
639 | for a section is found. | |
640 | ||
641 | For instance, an object file might contain both .mdebug (XCOFF) | |
642 | and .debug_info (DWARF2) sections then .mdebug is inserted first | |
643 | (searched last) and DWARF2 is inserted last (searched first). If | |
644 | we don't do this then the XCOFF info is found first - for code in | |
645 | an included file XCOFF info is useless. */ | |
646 | ||
647 | if (ei.mdebugsect) | |
648 | { | |
649 | const struct ecoff_debug_swap *swap; | |
650 | ||
651 | /* .mdebug section, presumably holding ECOFF debugging | |
c5aa993b | 652 | information. */ |
c906108c SS |
653 | swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap; |
654 | if (swap) | |
d4f3574e | 655 | elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect); |
c906108c SS |
656 | } |
657 | if (ei.stabsect) | |
658 | { | |
659 | asection *str_sect; | |
660 | ||
661 | /* Stab sections have an associated string table that looks like | |
c5aa993b | 662 | a separate section. */ |
c906108c SS |
663 | str_sect = bfd_get_section_by_name (abfd, ".stabstr"); |
664 | ||
665 | /* FIXME should probably warn about a stab section without a stabstr. */ | |
666 | if (str_sect) | |
667 | elfstab_build_psymtabs (objfile, | |
c906108c | 668 | mainline, |
086df311 | 669 | ei.stabsect, |
c906108c SS |
670 | str_sect->filepos, |
671 | bfd_section_size (abfd, str_sect)); | |
672 | } | |
c5edf76a | 673 | if (dwarf2_has_info (objfile)) |
c906108c SS |
674 | { |
675 | /* DWARF 2 sections */ | |
d4f3574e | 676 | dwarf2_build_psymtabs (objfile, mainline); |
c906108c | 677 | } |
c906108c | 678 | |
625b0b97 AC |
679 | /* FIXME: kettenis/20030504: This still needs to be integrated with |
680 | dwarf2read.c in a better way. */ | |
681 | dwarf2_build_frame_info (objfile); | |
c906108c SS |
682 | } |
683 | ||
0a6ddd08 AC |
684 | /* This cleans up the objfile's deprecated_sym_stab_info pointer, and |
685 | the chain of stab_section_info's, that might be dangling from | |
686 | it. */ | |
c906108c SS |
687 | |
688 | static void | |
12b9c64f | 689 | free_elfinfo (void *objp) |
c906108c | 690 | { |
c5aa993b | 691 | struct objfile *objfile = (struct objfile *) objp; |
0a6ddd08 | 692 | struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info; |
c906108c SS |
693 | struct stab_section_info *ssi, *nssi; |
694 | ||
695 | ssi = dbxinfo->stab_section_info; | |
696 | while (ssi) | |
697 | { | |
698 | nssi = ssi->next; | |
2dc74dc1 | 699 | xfree (ssi); |
c906108c SS |
700 | ssi = nssi; |
701 | } | |
702 | ||
703 | dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */ | |
704 | } | |
705 | ||
706 | ||
707 | /* Initialize anything that needs initializing when a completely new symbol | |
708 | file is specified (not just adding some symbols from another file, e.g. a | |
709 | shared library). | |
710 | ||
711 | We reinitialize buildsym, since we may be reading stabs from an ELF file. */ | |
712 | ||
713 | static void | |
fba45db2 | 714 | elf_new_init (struct objfile *ignore) |
c906108c SS |
715 | { |
716 | stabsread_new_init (); | |
717 | buildsym_new_init (); | |
718 | } | |
719 | ||
720 | /* Perform any local cleanups required when we are done with a particular | |
721 | objfile. I.E, we are in the process of discarding all symbol information | |
722 | for an objfile, freeing up all memory held for it, and unlinking the | |
723 | objfile struct from the global list of known objfiles. */ | |
724 | ||
725 | static void | |
fba45db2 | 726 | elf_symfile_finish (struct objfile *objfile) |
c906108c | 727 | { |
0a6ddd08 | 728 | if (objfile->deprecated_sym_stab_info != NULL) |
c906108c | 729 | { |
0a6ddd08 | 730 | xfree (objfile->deprecated_sym_stab_info); |
c906108c | 731 | } |
fe3e1990 DJ |
732 | |
733 | dwarf2_free_objfile (objfile); | |
c906108c SS |
734 | } |
735 | ||
736 | /* ELF specific initialization routine for reading symbols. | |
737 | ||
738 | It is passed a pointer to a struct sym_fns which contains, among other | |
739 | things, the BFD for the file whose symbols are being read, and a slot for | |
740 | a pointer to "private data" which we can fill with goodies. | |
741 | ||
742 | For now at least, we have nothing in particular to do, so this function is | |
743 | just a stub. */ | |
744 | ||
745 | static void | |
fba45db2 | 746 | elf_symfile_init (struct objfile *objfile) |
c906108c SS |
747 | { |
748 | /* ELF objects may be reordered, so set OBJF_REORDERED. If we | |
749 | find this causes a significant slowdown in gdb then we could | |
750 | set it in the debug symbol readers only when necessary. */ | |
751 | objfile->flags |= OBJF_REORDERED; | |
752 | } | |
753 | ||
754 | /* When handling an ELF file that contains Sun STABS debug info, | |
755 | some of the debug info is relative to the particular chunk of the | |
756 | section that was generated in its individual .o file. E.g. | |
757 | offsets to static variables are relative to the start of the data | |
758 | segment *for that module before linking*. This information is | |
759 | painfully squirreled away in the ELF symbol table as local symbols | |
760 | with wierd names. Go get 'em when needed. */ | |
761 | ||
762 | void | |
fba45db2 | 763 | elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst) |
c906108c SS |
764 | { |
765 | char *filename = pst->filename; | |
0a6ddd08 | 766 | struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info; |
c906108c SS |
767 | struct stab_section_info *maybe = dbx->stab_section_info; |
768 | struct stab_section_info *questionable = 0; | |
769 | int i; | |
770 | char *p; | |
771 | ||
772 | /* The ELF symbol info doesn't include path names, so strip the path | |
773 | (if any) from the psymtab filename. */ | |
774 | while (0 != (p = strchr (filename, '/'))) | |
c5aa993b | 775 | filename = p + 1; |
c906108c SS |
776 | |
777 | /* FIXME: This linear search could speed up significantly | |
778 | if it was chained in the right order to match how we search it, | |
779 | and if we unchained when we found a match. */ | |
780 | for (; maybe; maybe = maybe->next) | |
781 | { | |
782 | if (filename[0] == maybe->filename[0] | |
6314a349 | 783 | && strcmp (filename, maybe->filename) == 0) |
c906108c SS |
784 | { |
785 | /* We found a match. But there might be several source files | |
786 | (from different directories) with the same name. */ | |
787 | if (0 == maybe->found) | |
788 | break; | |
c5aa993b | 789 | questionable = maybe; /* Might use it later. */ |
c906108c SS |
790 | } |
791 | } | |
792 | ||
793 | if (maybe == 0 && questionable != 0) | |
794 | { | |
23136709 | 795 | complaint (&symfile_complaints, |
e2e0b3e5 | 796 | _("elf/stab section information questionable for %s"), filename); |
c906108c SS |
797 | maybe = questionable; |
798 | } | |
799 | ||
800 | if (maybe) | |
801 | { | |
802 | /* Found it! Allocate a new psymtab struct, and fill it in. */ | |
803 | maybe->found++; | |
804 | pst->section_offsets = (struct section_offsets *) | |
8b92e4d5 | 805 | obstack_alloc (&objfile->objfile_obstack, |
a39a16c4 MM |
806 | SIZEOF_N_SECTION_OFFSETS (objfile->num_sections)); |
807 | for (i = 0; i < maybe->num_sections; i++) | |
a4c8257b | 808 | (pst->section_offsets)->offsets[i] = maybe->sections[i]; |
c906108c SS |
809 | return; |
810 | } | |
811 | ||
812 | /* We were unable to find any offsets for this file. Complain. */ | |
c5aa993b | 813 | if (dbx->stab_section_info) /* If there *is* any info, */ |
23136709 | 814 | complaint (&symfile_complaints, |
e2e0b3e5 | 815 | _("elf/stab section information missing for %s"), filename); |
c906108c SS |
816 | } |
817 | \f | |
818 | /* Register that we are able to handle ELF object file formats. */ | |
819 | ||
820 | static struct sym_fns elf_sym_fns = | |
821 | { | |
822 | bfd_target_elf_flavour, | |
c5aa993b JM |
823 | elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ |
824 | elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ | |
825 | elf_symfile_read, /* sym_read: read a symbol file into symtab */ | |
826 | elf_symfile_finish, /* sym_finish: finished with file, cleanup */ | |
96baa820 | 827 | default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */ |
31d99776 DJ |
828 | elf_symfile_segments, /* sym_segments: Get segment information from |
829 | a file. */ | |
c295b2e5 | 830 | NULL, /* sym_read_linetable */ |
c5aa993b | 831 | NULL /* next: pointer to next struct sym_fns */ |
c906108c SS |
832 | }; |
833 | ||
834 | void | |
fba45db2 | 835 | _initialize_elfread (void) |
c906108c SS |
836 | { |
837 | add_symtab_fns (&elf_sym_fns); | |
838 | } |