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c906108c SS |
1 | /* Read a symbol table in MIPS' format (Third-Eye). |
2 | Copyright 1986, 87, 89, 90, 91, 92, 93, 94, 95, 96, 1998 | |
3 | Free Software Foundation, Inc. | |
4 | Contributed by Alessandro Forin (af@cs.cmu.edu) at CMU. Major work | |
5 | by Per Bothner, John Gilmore and Ian Lance Taylor 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 2 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, write to the Free Software | |
21 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
22 | ||
23 | /* Read symbols from an ECOFF file. Most of the work is done in | |
24 | mdebugread.c. */ | |
25 | ||
26 | #include "defs.h" | |
27 | #include "gdb_string.h" | |
28 | #include "bfd.h" | |
29 | #include "symtab.h" | |
30 | #include "symfile.h" | |
31 | #include "objfiles.h" | |
32 | #include "buildsym.h" | |
33 | #include "stabsread.h" | |
34 | #include "gdb-stabs.h" | |
35 | ||
36 | #include "coff/sym.h" | |
37 | #include "coff/internal.h" | |
38 | #include "coff/ecoff.h" | |
39 | #include "libcoff.h" /* Private BFD COFF information. */ | |
40 | #include "libecoff.h" /* Private BFD ECOFF information. */ | |
41 | #include "elf/common.h" | |
42 | #include "elf/mips.h" | |
43 | ||
392a587b JM |
44 | extern void _initialize_mipsread PARAMS ((void)); |
45 | ||
c906108c SS |
46 | static void |
47 | mipscoff_new_init PARAMS ((struct objfile *)); | |
48 | ||
49 | static void | |
50 | mipscoff_symfile_init PARAMS ((struct objfile *)); | |
51 | ||
52 | static void | |
53 | mipscoff_symfile_read PARAMS ((struct objfile *, struct section_offsets *, | |
54 | int)); | |
55 | ||
56 | static void | |
57 | mipscoff_symfile_finish PARAMS ((struct objfile *)); | |
58 | ||
59 | static void | |
60 | read_alphacoff_dynamic_symtab PARAMS ((struct section_offsets *, | |
61 | struct objfile *objfile)); | |
62 | ||
63 | /* Initialize anything that needs initializing when a completely new | |
64 | symbol file is specified (not just adding some symbols from another | |
65 | file, e.g. a shared library). */ | |
66 | ||
67 | extern CORE_ADDR sigtramp_address; | |
68 | ||
69 | static void | |
70 | mipscoff_new_init (ignore) | |
71 | struct objfile *ignore; | |
72 | { | |
73 | sigtramp_address = 0; | |
74 | stabsread_new_init (); | |
75 | buildsym_new_init (); | |
76 | } | |
77 | ||
78 | /* Initialize to read a symbol file (nothing to do). */ | |
79 | ||
80 | static void | |
81 | mipscoff_symfile_init (objfile) | |
82 | struct objfile *objfile; | |
83 | { | |
84 | } | |
85 | ||
86 | /* Read a symbol file from a file. */ | |
87 | ||
88 | static void | |
89 | mipscoff_symfile_read (objfile, section_offsets, mainline) | |
90 | struct objfile *objfile; | |
91 | struct section_offsets *section_offsets; | |
92 | int mainline; | |
93 | { | |
94 | bfd *abfd = objfile->obfd; | |
95 | struct cleanup * back_to; | |
96 | ||
97 | init_minimal_symbol_collection (); | |
98 | back_to = make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0); | |
99 | ||
100 | /* Now that the executable file is positioned at symbol table, | |
101 | process it and define symbols accordingly. */ | |
102 | ||
103 | if (!((*ecoff_backend (abfd)->debug_swap.read_debug_info) | |
104 | (abfd, (asection *) NULL, &ecoff_data (abfd)->debug_info))) | |
105 | error ("Error reading symbol table: %s", bfd_errmsg (bfd_get_error ())); | |
106 | ||
107 | mdebug_build_psymtabs (objfile, &ecoff_backend (abfd)->debug_swap, | |
108 | &ecoff_data (abfd)->debug_info, section_offsets); | |
109 | ||
110 | /* Add alpha coff dynamic symbols. */ | |
111 | ||
112 | read_alphacoff_dynamic_symtab (section_offsets, objfile); | |
113 | ||
114 | /* Install any minimal symbols that have been collected as the current | |
115 | minimal symbols for this objfile. */ | |
116 | ||
117 | install_minimal_symbols (objfile); | |
118 | ||
119 | /* If the entry_file bounds are still unknown after processing the | |
120 | partial symbols, then try to set them from the minimal symbols | |
121 | surrounding the entry_point. */ | |
122 | ||
123 | if (mainline | |
124 | && objfile->ei.entry_point != INVALID_ENTRY_POINT | |
125 | && objfile->ei.entry_file_lowpc == INVALID_ENTRY_LOWPC) | |
126 | { | |
127 | struct minimal_symbol *m; | |
128 | ||
129 | m = lookup_minimal_symbol_by_pc (objfile->ei.entry_point); | |
130 | if (m && SYMBOL_NAME (m + 1)) | |
131 | { | |
132 | objfile->ei.entry_file_lowpc = SYMBOL_VALUE_ADDRESS (m); | |
133 | objfile->ei.entry_file_highpc = SYMBOL_VALUE_ADDRESS (m + 1); | |
134 | } | |
135 | } | |
136 | ||
137 | do_cleanups (back_to); | |
138 | } | |
139 | ||
140 | /* Perform any local cleanups required when we are done with a | |
141 | particular objfile. */ | |
142 | ||
143 | static void | |
144 | mipscoff_symfile_finish (objfile) | |
145 | struct objfile *objfile; | |
146 | { | |
147 | } | |
148 | ||
149 | /* Alpha OSF/1 encapsulates the dynamic symbols in ELF format in a | |
150 | standard coff section. The ELF format for the symbols differs from | |
151 | the format defined in elf/external.h. It seems that a normal ELF 32 bit | |
152 | format is used, and the representation only changes because longs are | |
153 | 64 bit on the alpha. In addition, the handling of text/data section | |
154 | indices for symbols is different from the ELF ABI. | |
155 | As the BFD linker currently does not support dynamic linking on the alpha, | |
156 | there seems to be no reason to pollute BFD with another mixture of object | |
157 | file formats for now. */ | |
158 | ||
159 | /* Format of an alpha external ELF symbol. */ | |
160 | ||
161 | typedef struct { | |
162 | unsigned char st_name[4]; /* Symbol name, index in string tbl */ | |
163 | unsigned char st_pad[4]; /* Pad to long word boundary */ | |
164 | unsigned char st_value[8]; /* Value of the symbol */ | |
165 | unsigned char st_size[4]; /* Associated symbol size */ | |
166 | unsigned char st_info[1]; /* Type and binding attributes */ | |
167 | unsigned char st_other[1]; /* No defined meaning, 0 */ | |
168 | unsigned char st_shndx[2]; /* Associated section index */ | |
169 | } Elfalpha_External_Sym; | |
170 | ||
171 | /* Format of an alpha external ELF dynamic info structure. */ | |
172 | ||
173 | typedef struct { | |
174 | unsigned char d_tag[4]; /* Tag */ | |
175 | unsigned char d_pad[4]; /* Pad to long word boundary */ | |
176 | union { | |
177 | unsigned char d_ptr[8]; /* Pointer value */ | |
178 | unsigned char d_val[4]; /* Integer value */ | |
179 | } d_un; | |
180 | } Elfalpha_External_Dyn; | |
181 | ||
182 | /* Struct to obtain the section pointers for alpha dynamic symbol info. */ | |
183 | ||
184 | struct alphacoff_dynsecinfo { | |
185 | asection *sym_sect; /* Section pointer for .dynsym section */ | |
186 | asection *str_sect; /* Section pointer for .dynstr section */ | |
187 | asection *dyninfo_sect; /* Section pointer for .dynamic section */ | |
188 | asection *got_sect; /* Section pointer for .got section */ | |
189 | }; | |
190 | ||
191 | static void | |
192 | alphacoff_locate_sections PARAMS ((bfd *, asection *, void *)); | |
193 | ||
194 | /* We are called once per section from read_alphacoff_dynamic_symtab. | |
195 | We need to examine each section we are passed, check to see | |
196 | if it is something we are interested in processing, and | |
197 | if so, stash away some access information for the section. */ | |
198 | ||
199 | static void | |
200 | alphacoff_locate_sections (ignore_abfd, sectp, sip) | |
201 | bfd *ignore_abfd; | |
202 | asection *sectp; | |
203 | PTR sip; | |
204 | { | |
205 | register struct alphacoff_dynsecinfo *si; | |
206 | ||
207 | si = (struct alphacoff_dynsecinfo *) sip; | |
208 | ||
209 | if (STREQ (sectp->name, ".dynsym")) | |
210 | { | |
211 | si->sym_sect = sectp; | |
212 | } | |
213 | else if (STREQ (sectp->name, ".dynstr")) | |
214 | { | |
215 | si->str_sect = sectp; | |
216 | } | |
217 | else if (STREQ (sectp->name, ".dynamic")) | |
218 | { | |
219 | si->dyninfo_sect = sectp; | |
220 | } | |
221 | else if (STREQ (sectp->name, ".got")) | |
222 | { | |
223 | si->got_sect = sectp; | |
224 | } | |
225 | } | |
226 | ||
227 | /* Scan an alpha dynamic symbol table for symbols of interest and | |
228 | add them to the minimal symbol table. */ | |
229 | ||
230 | static void | |
231 | read_alphacoff_dynamic_symtab (section_offsets, objfile) | |
232 | struct section_offsets *section_offsets; | |
233 | struct objfile *objfile; | |
234 | { | |
235 | bfd *abfd = objfile->obfd; | |
236 | struct alphacoff_dynsecinfo si; | |
237 | char *sym_secptr; | |
238 | char *str_secptr; | |
239 | char *dyninfo_secptr; | |
240 | char *got_secptr; | |
241 | bfd_size_type sym_secsize; | |
242 | bfd_size_type str_secsize; | |
243 | bfd_size_type dyninfo_secsize; | |
244 | bfd_size_type got_secsize; | |
245 | int sym_count; | |
246 | int i; | |
247 | int stripped; | |
248 | Elfalpha_External_Sym *x_symp; | |
249 | char *dyninfo_p; | |
250 | char *dyninfo_end; | |
251 | int got_entry_size = 8; | |
252 | int dt_mips_local_gotno = -1; | |
253 | int dt_mips_gotsym = -1; | |
254 | ||
255 | ||
256 | /* We currently only know how to handle alpha dynamic symbols. */ | |
257 | if (bfd_get_arch (abfd) != bfd_arch_alpha) | |
258 | return; | |
259 | ||
260 | /* Locate the dynamic symbols sections and read them in. */ | |
261 | memset ((char *) &si, 0, sizeof (si)); | |
262 | bfd_map_over_sections (abfd, alphacoff_locate_sections, (PTR) &si); | |
263 | if (si.sym_sect == NULL | |
264 | || si.str_sect == NULL | |
265 | || si.dyninfo_sect == NULL | |
266 | || si.got_sect == NULL) | |
267 | return; | |
268 | ||
269 | sym_secsize = bfd_get_section_size_before_reloc (si.sym_sect); | |
270 | str_secsize = bfd_get_section_size_before_reloc (si.str_sect); | |
271 | dyninfo_secsize = bfd_get_section_size_before_reloc (si.dyninfo_sect); | |
272 | got_secsize = bfd_get_section_size_before_reloc (si.got_sect); | |
273 | sym_secptr = alloca (sym_secsize); | |
274 | str_secptr = alloca (str_secsize); | |
275 | dyninfo_secptr = alloca (dyninfo_secsize); | |
276 | got_secptr = alloca (got_secsize); | |
277 | ||
278 | if (!bfd_get_section_contents (abfd, si.sym_sect, sym_secptr, | |
279 | (file_ptr)0, sym_secsize)) | |
280 | return; | |
281 | if (!bfd_get_section_contents (abfd, si.str_sect, str_secptr, | |
282 | (file_ptr)0, str_secsize)) | |
283 | return; | |
284 | if (!bfd_get_section_contents (abfd, si.dyninfo_sect, dyninfo_secptr, | |
285 | (file_ptr)0, dyninfo_secsize)) | |
286 | return; | |
287 | if (!bfd_get_section_contents (abfd, si.got_sect, got_secptr, | |
288 | (file_ptr)0, got_secsize)) | |
289 | return; | |
290 | ||
291 | /* Find the number of local GOT entries and the index for the | |
292 | the first dynamic symbol in the GOT. */ | |
293 | for (dyninfo_p = dyninfo_secptr, dyninfo_end = dyninfo_p + dyninfo_secsize; | |
294 | dyninfo_p < dyninfo_end; | |
295 | dyninfo_p += sizeof (Elfalpha_External_Dyn)) | |
296 | { | |
297 | Elfalpha_External_Dyn *x_dynp = (Elfalpha_External_Dyn *)dyninfo_p; | |
298 | long dyn_tag; | |
299 | ||
300 | dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_tag); | |
301 | if (dyn_tag == DT_NULL) | |
302 | break; | |
303 | else if (dyn_tag == DT_MIPS_LOCAL_GOTNO) | |
304 | { | |
305 | if (dt_mips_local_gotno < 0) | |
306 | dt_mips_local_gotno | |
307 | = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_un.d_val); | |
308 | } | |
309 | else if (dyn_tag == DT_MIPS_GOTSYM) | |
310 | { | |
311 | if (dt_mips_gotsym < 0) | |
312 | dt_mips_gotsym | |
313 | = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_un.d_val); | |
314 | } | |
315 | } | |
316 | if (dt_mips_local_gotno < 0 || dt_mips_gotsym < 0) | |
317 | return; | |
318 | ||
319 | /* Scan all dynamic symbols and enter them into the minimal symbol table | |
320 | if appropriate. */ | |
321 | sym_count = sym_secsize / sizeof (Elfalpha_External_Sym); | |
322 | stripped = (bfd_get_symcount (abfd) == 0); | |
323 | ||
324 | /* Skip first symbol, which is a null dummy. */ | |
325 | for (i = 1, x_symp = (Elfalpha_External_Sym *) sym_secptr + 1; | |
326 | i < sym_count; | |
327 | i++, x_symp++) | |
328 | { | |
329 | unsigned long strx; | |
330 | char *name; | |
331 | bfd_vma sym_value; | |
332 | unsigned char sym_info; | |
333 | unsigned int sym_shndx; | |
334 | int isglobal; | |
335 | enum minimal_symbol_type ms_type; | |
336 | ||
337 | strx = bfd_h_get_32 (abfd, (bfd_byte *) x_symp->st_name); | |
338 | if (strx >= str_secsize) | |
339 | continue; | |
340 | name = str_secptr + strx; | |
341 | if (*name == '\0' || *name == '.') | |
342 | continue; | |
343 | ||
344 | sym_value = bfd_h_get_64 (abfd, (bfd_byte *) x_symp->st_value); | |
345 | sym_info = bfd_h_get_8 (abfd, (bfd_byte *) x_symp->st_info); | |
346 | sym_shndx = bfd_h_get_16 (abfd, (bfd_byte *) x_symp->st_shndx); | |
347 | isglobal = (ELF_ST_BIND (sym_info) == STB_GLOBAL); | |
348 | ||
349 | if (sym_shndx == SHN_UNDEF) | |
350 | { | |
351 | /* Handle undefined functions which are defined in a shared | |
352 | library. */ | |
353 | if (ELF_ST_TYPE (sym_info) != STT_FUNC | |
354 | || ELF_ST_BIND (sym_info) != STB_GLOBAL) | |
355 | continue; | |
356 | ||
357 | ms_type = mst_solib_trampoline; | |
358 | ||
359 | /* If sym_value is nonzero, it points to the shared library | |
360 | trampoline entry, which is what we are looking for. | |
361 | ||
362 | If sym_value is zero, then we have to get the GOT entry | |
363 | for the symbol. | |
364 | If the GOT entry is nonzero, it represents the quickstart | |
365 | address of the function and we use that as the symbol value. | |
366 | ||
367 | If the GOT entry is zero, the function address has to be resolved | |
368 | by the runtime loader before the executable is started. | |
369 | We are unable to find any meaningful address for these | |
370 | functions in the executable file, so we skip them. */ | |
371 | if (sym_value == 0) | |
372 | { | |
373 | int got_entry_offset = | |
374 | (i - dt_mips_gotsym + dt_mips_local_gotno) * got_entry_size; | |
375 | ||
376 | if (got_entry_offset < 0 || got_entry_offset >= got_secsize) | |
377 | continue; | |
378 | sym_value = | |
379 | bfd_h_get_64 (abfd, | |
380 | (bfd_byte *) (got_secptr + got_entry_offset)); | |
381 | if (sym_value == 0) | |
382 | continue; | |
383 | } | |
384 | } | |
385 | else | |
386 | { | |
387 | /* Symbols defined in the executable itself. We only care about | |
388 | them if this is a stripped executable, otherwise they have | |
389 | been retrieved from the normal symbol table already. */ | |
390 | if (!stripped) | |
391 | continue; | |
392 | ||
393 | if (sym_shndx == SHN_MIPS_TEXT) | |
394 | { | |
395 | if (isglobal) | |
396 | ms_type = mst_text; | |
397 | else | |
398 | ms_type = mst_file_text; | |
399 | sym_value += ANOFFSET (section_offsets, SECT_OFF_TEXT); | |
400 | } | |
401 | else if (sym_shndx == SHN_MIPS_DATA) | |
402 | { | |
403 | if (isglobal) | |
404 | ms_type = mst_data; | |
405 | else | |
406 | ms_type = mst_file_data; | |
407 | sym_value += ANOFFSET (section_offsets, SECT_OFF_DATA); | |
408 | } | |
409 | else if (sym_shndx == SHN_MIPS_ACOMMON) | |
410 | { | |
411 | if (isglobal) | |
412 | ms_type = mst_bss; | |
413 | else | |
414 | ms_type = mst_file_bss; | |
415 | sym_value += ANOFFSET (section_offsets, SECT_OFF_BSS); | |
416 | } | |
417 | else if (sym_shndx == SHN_ABS) | |
418 | { | |
419 | ms_type = mst_abs; | |
420 | } | |
421 | else | |
422 | { | |
423 | continue; | |
424 | } | |
425 | } | |
426 | ||
427 | prim_record_minimal_symbol (name, sym_value, ms_type, objfile); | |
428 | } | |
429 | } | |
430 | ||
431 | /* Initialization */ | |
432 | ||
433 | static struct sym_fns ecoff_sym_fns = | |
434 | { | |
435 | bfd_target_ecoff_flavour, | |
436 | mipscoff_new_init, /* sym_new_init: init anything gbl to entire symtab */ | |
437 | mipscoff_symfile_init, /* sym_init: read initial info, setup for sym_read() */ | |
438 | mipscoff_symfile_read, /* sym_read: read a symbol file into symtab */ | |
439 | mipscoff_symfile_finish, /* sym_finish: finished with file, cleanup */ | |
440 | default_symfile_offsets, /* sym_offsets: dummy FIXME til implem sym reloc */ | |
441 | NULL /* next: pointer to next struct sym_fns */ | |
442 | }; | |
443 | ||
444 | void | |
445 | _initialize_mipsread () | |
446 | { | |
447 | add_symtab_fns (&ecoff_sym_fns); | |
448 | } |