Commit | Line | Data |
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35f5886e | 1 | /* Read ELF (Executable and Linking Format) object files for GDB. |
c2e4669f | 2 | Copyright 1991, 1992 Free Software Foundation, Inc. |
35f5886e FF |
3 | Written by Fred Fish at Cygnus Support. |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
20 | ||
21 | /************************************************************************ | |
22 | * * | |
23 | * NOTICE * | |
24 | * * | |
25 | * This file is still under construction. When it is complete, this * | |
26 | * notice will be removed. Until then, direct any questions or changes * | |
c2e4669f | 27 | * to Fred Fish at Cygnus Support (fnf@cygnus.com) * |
35f5886e FF |
28 | * * |
29 | * FIXME Still needs support for shared libraries. * | |
30 | * FIXME Still needs support for core files. * | |
31 | * FIXME The ".debug" and ".line" section names are hardwired. * | |
35f5886e FF |
32 | * * |
33 | ************************************************************************/ | |
34 | ||
35f5886e | 35 | #include "defs.h" |
f5f0679a SC |
36 | #include "elf/common.h" |
37 | #include "elf/external.h" | |
38 | #include "elf/internal.h" | |
35f5886e | 39 | #include "bfd.h" |
f70be3e4 | 40 | #include "libbfd.h" /* For bfd_elf_find_section */ |
35f5886e | 41 | #include "symtab.h" |
1ab3bf1b | 42 | #include "symfile.h" |
5e2e79f8 | 43 | #include "objfiles.h" |
be772100 | 44 | #include "buildsym.h" |
a048c8f5 | 45 | |
35f5886e FF |
46 | #define STREQ(a,b) (strcmp((a),(b))==0) |
47 | ||
48 | struct elfinfo { | |
49 | unsigned int dboffset; /* Offset to dwarf debug section */ | |
50 | unsigned int dbsize; /* Size of dwarf debug section */ | |
51 | unsigned int lnoffset; /* Offset to dwarf line number section */ | |
52 | unsigned int lnsize; /* Size of dwarf line number section */ | |
346168a2 JG |
53 | asection *stabsect; /* Section pointer for .stab section */ |
54 | asection *stabindexsect; /* Section pointer for .stab.index section */ | |
35f5886e FF |
55 | }; |
56 | ||
1ab3bf1b | 57 | static void |
80d68b1d | 58 | elf_symfile_init PARAMS ((struct objfile *)); |
1ab3bf1b JG |
59 | |
60 | static void | |
80d68b1d | 61 | elf_new_init PARAMS ((struct objfile *)); |
1ab3bf1b JG |
62 | |
63 | static void | |
80d68b1d FF |
64 | elf_symfile_read PARAMS ((struct objfile *, CORE_ADDR, int)); |
65 | ||
66 | static void | |
67 | elf_symfile_finish PARAMS ((struct objfile *)); | |
1ab3bf1b JG |
68 | |
69 | static void | |
be772100 | 70 | elf_symtab_read PARAMS ((bfd *, CORE_ADDR, struct objfile *)); |
1ab3bf1b | 71 | |
51b57ded | 72 | #if 0 |
1ab3bf1b JG |
73 | static void |
74 | record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type, | |
75 | struct objfile *)); | |
51b57ded FF |
76 | #endif |
77 | ||
78 | static void | |
79 | record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR, | |
80 | enum minimal_symbol_type, char *, | |
81 | struct objfile *)); | |
1ab3bf1b JG |
82 | |
83 | static void | |
84 | elf_locate_sections PARAMS ((bfd *, asection *, PTR)); | |
85 | ||
35f5886e FF |
86 | /* We are called once per section from elf_symfile_read. We |
87 | need to examine each section we are passed, check to see | |
88 | if it is something we are interested in processing, and | |
89 | if so, stash away some access information for the section. | |
90 | ||
91 | For now we recognize the dwarf debug information sections and | |
92 | line number sections from matching their section names. The | |
93 | ELF definition is no real help here since it has no direct | |
94 | knowledge of DWARF (by design, so any debugging format can be | |
95 | used). | |
96 | ||
346168a2 JG |
97 | We also recognize the ".stab" sections used by the Sun compilers |
98 | released with Solaris 2. | |
99 | ||
35f5886e FF |
100 | FIXME: The section names should not be hardwired strings. */ |
101 | ||
102 | static void | |
be772100 JG |
103 | elf_locate_sections (ignore_abfd, sectp, eip) |
104 | bfd *ignore_abfd; | |
1ab3bf1b JG |
105 | asection *sectp; |
106 | PTR eip; | |
35f5886e | 107 | { |
1ab3bf1b JG |
108 | register struct elfinfo *ei; |
109 | ||
110 | ei = (struct elfinfo *) eip; | |
35f5886e FF |
111 | if (STREQ (sectp -> name, ".debug")) |
112 | { | |
113 | ei -> dboffset = sectp -> filepos; | |
e5849334 | 114 | ei -> dbsize = bfd_get_section_size_before_reloc (sectp); |
35f5886e FF |
115 | } |
116 | else if (STREQ (sectp -> name, ".line")) | |
117 | { | |
118 | ei -> lnoffset = sectp -> filepos; | |
e5849334 | 119 | ei -> lnsize = bfd_get_section_size_before_reloc (sectp); |
35f5886e | 120 | } |
346168a2 JG |
121 | else if (STREQ (sectp -> name, ".stab")) |
122 | { | |
123 | ei -> stabsect = sectp; | |
124 | } | |
125 | else if (STREQ (sectp -> name, ".stab.index")) | |
126 | { | |
127 | ei -> stabindexsect = sectp; | |
128 | } | |
35f5886e FF |
129 | } |
130 | ||
1ab3bf1b JG |
131 | #if 0 /* Currently unused */ |
132 | ||
f8b76e70 | 133 | char * |
1ab3bf1b JG |
134 | elf_interpreter (abfd) |
135 | bfd *abfd; | |
f8b76e70 FF |
136 | { |
137 | sec_ptr interp_sec; | |
138 | unsigned size; | |
139 | char *interp = NULL; | |
140 | ||
141 | interp_sec = bfd_get_section_by_name (abfd, ".interp"); | |
142 | if (interp_sec) | |
143 | { | |
144 | size = bfd_section_size (abfd, interp_sec); | |
145 | interp = alloca (size); | |
146 | if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0, | |
147 | size)) | |
148 | { | |
149 | interp = savestring (interp, size - 1); | |
150 | } | |
151 | else | |
152 | { | |
153 | interp = NULL; | |
154 | } | |
155 | } | |
156 | return (interp); | |
157 | } | |
158 | ||
1ab3bf1b JG |
159 | #endif |
160 | ||
a7446af6 FF |
161 | /* |
162 | ||
163 | LOCAL FUNCTION | |
164 | ||
1ab3bf1b | 165 | record_minimal_symbol -- add entry to minimal symbol table |
a7446af6 FF |
166 | |
167 | SYNOPSIS | |
168 | ||
1ab3bf1b | 169 | static void record_minimal_symbol (char *name, CORE_ADDR address) |
a7446af6 FF |
170 | |
171 | DESCRIPTION | |
172 | ||
173 | Given a pointer to the name of a symbol that should be added to the | |
1ab3bf1b JG |
174 | minimal symbol table and the address associated with that symbol, records |
175 | this information for later use in building the minimal symbol table. | |
a7446af6 | 176 | |
a7446af6 FF |
177 | */ |
178 | ||
51b57ded FF |
179 | #if 0 /* FIXME: Unused */ |
180 | ||
a7446af6 | 181 | static void |
1ab3bf1b JG |
182 | record_minimal_symbol (name, address, ms_type, objfile) |
183 | char *name; | |
184 | CORE_ADDR address; | |
185 | enum minimal_symbol_type ms_type; | |
186 | struct objfile *objfile; | |
a7446af6 | 187 | { |
1ab3bf1b JG |
188 | name = obsavestring (name, strlen (name), &objfile -> symbol_obstack); |
189 | prim_record_minimal_symbol (name, address, ms_type); | |
a7446af6 FF |
190 | } |
191 | ||
51b57ded FF |
192 | #endif |
193 | ||
346168a2 JG |
194 | static void |
195 | record_minimal_symbol_and_info (name, address, ms_type, info, objfile) | |
196 | char *name; | |
197 | CORE_ADDR address; | |
198 | enum minimal_symbol_type ms_type; | |
199 | char *info; /* FIXME, is this really char *? */ | |
200 | struct objfile *objfile; | |
201 | { | |
202 | name = obsavestring (name, strlen (name), &objfile -> symbol_obstack); | |
203 | prim_record_minimal_symbol_and_info (name, address, ms_type, info); | |
204 | } | |
205 | ||
f8b76e70 FF |
206 | /* |
207 | ||
208 | LOCAL FUNCTION | |
209 | ||
210 | elf_symtab_read -- read the symbol table of an ELF file | |
211 | ||
212 | SYNOPSIS | |
213 | ||
be772100 | 214 | void elf_symtab_read (bfd *abfd, CORE_ADDR addr, |
1ab3bf1b | 215 | struct objfile *objfile) |
f8b76e70 FF |
216 | |
217 | DESCRIPTION | |
218 | ||
219 | Given an open bfd, a base address to relocate symbols to, and a | |
220 | flag that specifies whether or not this bfd is for an executable | |
221 | or not (may be shared library for example), add all the global | |
1ab3bf1b | 222 | function and data symbols to the minimal symbol table. |
f8b76e70 FF |
223 | |
224 | */ | |
225 | ||
a7446af6 | 226 | static void |
be772100 | 227 | elf_symtab_read (abfd, addr, objfile) |
1ab3bf1b JG |
228 | bfd *abfd; |
229 | CORE_ADDR addr; | |
1ab3bf1b | 230 | struct objfile *objfile; |
a7446af6 FF |
231 | { |
232 | unsigned int storage_needed; | |
233 | asymbol *sym; | |
234 | asymbol **symbol_table; | |
235 | unsigned int number_of_symbols; | |
236 | unsigned int i; | |
237 | struct cleanup *back_to; | |
f8b76e70 | 238 | CORE_ADDR symaddr; |
1ab3bf1b | 239 | enum minimal_symbol_type ms_type; |
a7446af6 FF |
240 | |
241 | storage_needed = get_symtab_upper_bound (abfd); | |
242 | ||
243 | if (storage_needed > 0) | |
244 | { | |
3b0b9220 | 245 | symbol_table = (asymbol **) xmalloc (storage_needed); |
a7446af6 FF |
246 | back_to = make_cleanup (free, symbol_table); |
247 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); | |
248 | ||
249 | for (i = 0; i < number_of_symbols; i++) | |
250 | { | |
251 | sym = *symbol_table++; | |
d35bf52d FF |
252 | /* Select global/weak symbols that are defined in a specific section. |
253 | Note that bfd now puts abs symbols in their own section, so | |
254 | all symbols we are interested in will have a section. */ | |
255 | if ((sym -> flags & (BSF_GLOBAL | BSF_WEAK)) | |
256 | && (sym -> section != NULL)) | |
a7446af6 | 257 | { |
f8b76e70 | 258 | symaddr = sym -> value; |
c2e4669f JG |
259 | /* Relocate all non-absolute symbols by base address. */ |
260 | if (sym -> section != &bfd_abs_section) | |
f8b76e70 | 261 | { |
f8b76e70 FF |
262 | symaddr += addr; |
263 | } | |
264 | /* For non-absolute symbols, use the type of the section | |
265 | they are relative to, to intuit text/data. Bfd provides | |
266 | no way of figuring this out for absolute symbols. */ | |
d35bf52d | 267 | if (sym -> section -> flags & SEC_CODE) |
f8b76e70 | 268 | { |
1ab3bf1b | 269 | ms_type = mst_text; |
f8b76e70 | 270 | } |
d35bf52d | 271 | else if (sym -> section -> flags & SEC_DATA) |
f8b76e70 | 272 | { |
1ab3bf1b | 273 | ms_type = mst_data; |
f8b76e70 FF |
274 | } |
275 | else | |
276 | { | |
1ab3bf1b | 277 | ms_type = mst_unknown; |
f8b76e70 | 278 | } |
346168a2 JG |
279 | /* Pass symbol size field in via BFD. FIXME!!! */ |
280 | record_minimal_symbol_and_info ((char *) sym -> name, | |
281 | symaddr, ms_type, sym->udata, objfile); | |
a7446af6 FF |
282 | } |
283 | } | |
284 | do_cleanups (back_to); | |
285 | } | |
286 | } | |
287 | ||
35f5886e FF |
288 | /* Scan and build partial symbols for a symbol file. |
289 | We have been initialized by a call to elf_symfile_init, which | |
290 | currently does nothing. | |
291 | ||
292 | ADDR is the address relative to which the symbols in it are (e.g. | |
293 | the base address of the text segment). | |
294 | ||
295 | MAINLINE is true if we are reading the main symbol | |
296 | table (as opposed to a shared lib or dynamically loaded file). | |
297 | ||
298 | This function only does the minimum work necessary for letting the | |
299 | user "name" things symbolically; it does not read the entire symtab. | |
300 | Instead, it reads the external and static symbols and puts them in partial | |
301 | symbol tables. When more extensive information is requested of a | |
302 | file, the corresponding partial symbol table is mutated into a full | |
303 | fledged symbol table by going back and reading the symbols | |
346168a2 JG |
304 | for real. |
305 | ||
306 | We look for sections with specific names, to tell us what debug | |
307 | format to look for: FIXME!!! | |
308 | ||
309 | dwarf_build_psymtabs() builds psymtabs for DWARF symbols; | |
310 | elfstab_build_psymtabs() handles STABS symbols. | |
a7446af6 FF |
311 | |
312 | Note that ELF files have a "minimal" symbol table, which looks a lot | |
313 | like a COFF symbol table, but has only the minimal information necessary | |
346168a2 JG |
314 | for linking. We process this also, and use the information to |
315 | build gdb's minimal symbol table. This gives us some minimal debugging | |
316 | capability even for files compiled without -g. */ | |
35f5886e FF |
317 | |
318 | static void | |
80d68b1d FF |
319 | elf_symfile_read (objfile, addr, mainline) |
320 | struct objfile *objfile; | |
1ab3bf1b JG |
321 | CORE_ADDR addr; |
322 | int mainline; | |
35f5886e | 323 | { |
80d68b1d | 324 | bfd *abfd = objfile->obfd; |
35f5886e | 325 | struct elfinfo ei; |
a7446af6 | 326 | struct cleanup *back_to; |
6b801388 | 327 | asection *text_sect; |
346168a2 | 328 | CORE_ADDR offset; |
35f5886e | 329 | |
1ab3bf1b JG |
330 | init_minimal_symbol_collection (); |
331 | back_to = make_cleanup (discard_minimal_symbols, 0); | |
a7446af6 | 332 | |
6b801388 FF |
333 | /* Compute the amount to relocate all symbols by. The value passed in |
334 | as ADDR is typically either the actual address of the text section, | |
335 | or a user specified address. By subtracting off the actual address | |
336 | of the text section, we can compute the relocation amount. */ | |
337 | ||
338 | text_sect = bfd_get_section_by_name (objfile -> obfd, ".text"); | |
346168a2 | 339 | offset = addr - bfd_section_vma (objfile -> obfd, text_sect); |
6b801388 | 340 | |
a7446af6 FF |
341 | /* Process the normal ELF symbol table first. */ |
342 | ||
346168a2 | 343 | elf_symtab_read (abfd, offset, objfile); |
a7446af6 | 344 | |
346168a2 | 345 | /* Now process debugging information, which is contained in |
a7446af6 FF |
346 | special ELF sections. We first have to find them... */ |
347 | ||
348 | (void) memset ((char *) &ei, 0, sizeof (ei)); | |
1ab3bf1b | 349 | bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei); |
35f5886e FF |
350 | if (ei.dboffset && ei.lnoffset) |
351 | { | |
346168a2 | 352 | /* DWARF sections */ |
35f5886e FF |
353 | dwarf_build_psymtabs (fileno ((FILE *)(abfd -> iostream)), |
354 | bfd_get_filename (abfd), | |
346168a2 | 355 | offset, mainline, |
35f5886e | 356 | ei.dboffset, ei.dbsize, |
80d68b1d | 357 | ei.lnoffset, ei.lnsize, objfile); |
35f5886e | 358 | } |
346168a2 JG |
359 | if (ei.stabsect) |
360 | { | |
361 | /* STABS sections */ | |
362 | ||
363 | /* FIXME: Sun didn't really know how to implement this well. | |
364 | They made .stab sections that don't point to the .stabstr | |
365 | section with the sh_link field. BFD doesn't make string table | |
366 | sections visible to the caller. So we have to search the | |
367 | ELF section table, not the BFD section table, for the string | |
368 | table. */ | |
f70be3e4 | 369 | struct elf_internal_shdr *elf_sect; |
346168a2 | 370 | |
f70be3e4 | 371 | elf_sect = bfd_elf_find_section (abfd, ".stabstr"); |
346168a2 JG |
372 | if (elf_sect) |
373 | elfstab_build_psymtabs (objfile, | |
374 | addr, /* We really pass the text seg addr, not the offset, here. */ | |
375 | mainline, | |
376 | ei.stabsect->filepos, /* .stab offset */ | |
377 | bfd_get_section_size_before_reloc (ei.stabsect),/* .stab size */ | |
378 | elf_sect->sh_offset, /* .stabstr offset */ | |
379 | elf_sect->sh_size); /* .stabstr size */ | |
380 | } | |
a7446af6 | 381 | |
1ab3bf1b | 382 | if (!have_partial_symbols ()) |
35f5886e FF |
383 | { |
384 | wrap_here (""); | |
385 | printf_filtered ("(no debugging symbols found)..."); | |
386 | wrap_here (""); | |
387 | } | |
a7446af6 | 388 | |
1ab3bf1b JG |
389 | /* Install any minimal symbols that have been collected as the current |
390 | minimal symbols for this objfile. */ | |
391 | ||
80d68b1d | 392 | install_minimal_symbols (objfile); |
1ab3bf1b | 393 | |
a7446af6 | 394 | do_cleanups (back_to); |
35f5886e FF |
395 | } |
396 | ||
397 | /* Initialize anything that needs initializing when a completely new symbol | |
398 | file is specified (not just adding some symbols from another file, e.g. a | |
399 | shared library). | |
400 | ||
346168a2 | 401 | We reinitialize buildsym, since we may be reading stabs from an ELF file. */ |
35f5886e FF |
402 | |
403 | static void | |
be772100 JG |
404 | elf_new_init (ignore) |
405 | struct objfile *ignore; | |
80d68b1d FF |
406 | { |
407 | buildsym_new_init (); | |
408 | } | |
409 | ||
410 | /* Perform any local cleanups required when we are done with a particular | |
411 | objfile. I.E, we are in the process of discarding all symbol information | |
412 | for an objfile, freeing up all memory held for it, and unlinking the | |
413 | objfile struct from the global list of known objfiles. */ | |
414 | ||
415 | static void | |
416 | elf_symfile_finish (objfile) | |
417 | struct objfile *objfile; | |
35f5886e | 418 | { |
80d68b1d FF |
419 | if (objfile -> sym_private != NULL) |
420 | { | |
421 | mfree (objfile -> md, objfile -> sym_private); | |
422 | } | |
35f5886e FF |
423 | } |
424 | ||
425 | /* ELF specific initialization routine for reading symbols. | |
426 | ||
427 | It is passed a pointer to a struct sym_fns which contains, among other | |
428 | things, the BFD for the file whose symbols are being read, and a slot for | |
429 | a pointer to "private data" which we can fill with goodies. | |
430 | ||
431 | For now at least, we have nothing in particular to do, so this function is | |
432 | just a stub. */ | |
433 | ||
434 | static void | |
be772100 JG |
435 | elf_symfile_init (ignore) |
436 | struct objfile *ignore; | |
35f5886e FF |
437 | { |
438 | } | |
439 | ||
440 | \f | |
441 | /* Register that we are able to handle ELF object file formats and DWARF | |
442 | debugging formats. | |
443 | ||
444 | Unlike other object file formats, where the debugging information format | |
445 | is implied by the object file format, the ELF object file format and the | |
446 | DWARF debugging information format are two distinct, and potentially | |
447 | separate entities. I.E. it is perfectly possible to have ELF objects | |
448 | with debugging formats other than DWARF. And it is conceivable that the | |
449 | DWARF debugging format might be used with another object file format, | |
450 | like COFF, by simply using COFF's custom section feature. | |
451 | ||
452 | GDB, and to a lesser extent BFD, should support the notion of separate | |
453 | object file formats and debugging information formats. For now, we just | |
454 | use "elf" in the same sense as "a.out" or "coff", to imply both the ELF | |
455 | object file format and the DWARF debugging format. */ | |
456 | ||
80d68b1d FF |
457 | static struct sym_fns elf_sym_fns = |
458 | { | |
35f5886e FF |
459 | "elf", /* sym_name: name or name prefix of BFD target type */ |
460 | 3, /* sym_namelen: number of significant sym_name chars */ | |
461 | elf_new_init, /* sym_new_init: init anything gbl to entire symtab */ | |
462 | elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */ | |
463 | elf_symfile_read, /* sym_read: read a symbol file into symtab */ | |
80d68b1d | 464 | elf_symfile_finish, /* sym_finish: finished with file, cleanup */ |
35f5886e FF |
465 | NULL /* next: pointer to next struct sym_fns */ |
466 | }; | |
467 | ||
468 | void | |
1ab3bf1b | 469 | _initialize_elfread () |
35f5886e FF |
470 | { |
471 | add_symtab_fns (&elf_sym_fns); | |
472 | } |