1 /* Read a symbol table in MIPS' format (Third-Eye).
3 Copyright (C) 1986-2016 Free Software Foundation, Inc.
5 Contributed by Alessandro Forin (af@cs.cmu.edu) at CMU. Major work
6 by Per Bothner, John Gilmore and Ian Lance Taylor at Cygnus Support.
8 This file is part of GDB.
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
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
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.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 /* Read symbols from an ECOFF file. Most of the work is done in
31 #include "stabsread.h"
34 #include "coff/internal.h"
35 #include "coff/ecoff.h"
36 #include "libcoff.h" /* Private BFD COFF information. */
37 #include "libecoff.h" /* Private BFD ECOFF information. */
38 #include "elf/common.h"
39 #include "elf/internal.h"
45 read_alphacoff_dynamic_symtab (struct section_offsets
*,
46 struct objfile
*objfile
);
48 /* Initialize anything that needs initializing when a completely new
49 symbol file is specified (not just adding some symbols from another
50 file, e.g. a shared library). */
53 mipscoff_new_init (struct objfile
*ignore
)
55 stabsread_new_init ();
59 /* Initialize to read a symbol file (nothing to do). */
62 mipscoff_symfile_init (struct objfile
*objfile
)
66 /* Read a symbol file from a file. */
69 mipscoff_symfile_read (struct objfile
*objfile
, int symfile_flags
)
71 bfd
*abfd
= objfile
->obfd
;
73 minimal_symbol_reader
reader (objfile
);
75 /* Now that the executable file is positioned at symbol table,
76 process it and define symbols accordingly. */
78 if (!((*ecoff_backend (abfd
)->debug_swap
.read_debug_info
)
79 (abfd
, (asection
*) NULL
, &ecoff_data (abfd
)->debug_info
)))
80 error (_("Error reading symbol table: %s"), bfd_errmsg (bfd_get_error ()));
82 mdebug_build_psymtabs (objfile
, &ecoff_backend (abfd
)->debug_swap
,
83 &ecoff_data (abfd
)->debug_info
);
85 /* Add alpha coff dynamic symbols. */
87 read_alphacoff_dynamic_symtab (objfile
->section_offsets
, objfile
);
89 /* Install any minimal symbols that have been collected as the current
90 minimal symbols for this objfile. */
95 /* Perform any local cleanups required when we are done with a
96 particular objfile. */
99 mipscoff_symfile_finish (struct objfile
*objfile
)
103 /* Alpha OSF/1 encapsulates the dynamic symbols in ELF format in a
104 standard COFF section. The ELF format for the symbols differs from
105 the format defined in elf/external.h. It seems that a normal ELF
106 32-bit format is used, and the representation only changes because
107 longs are 64-bit on the alpha. In addition, the handling of
108 text/data section indices for symbols is different from the ELF
109 ABI. As the BFD linker currently does not support dynamic linking
110 on the alpha, there seems to be no reason to pollute BFD with
111 another mixture of object file formats for now. */
113 /* Format of an alpha external ELF symbol. */
117 unsigned char st_name
[4]; /* Symbol name, index in string table. */
118 unsigned char st_pad
[4]; /* Pad to long word boundary. */
119 unsigned char st_value
[8]; /* Value of the symbol. */
120 unsigned char st_size
[4]; /* Associated symbol size. */
121 unsigned char st_info
[1]; /* Type and binding attributes. */
122 unsigned char st_other
[1]; /* No defined meaning, 0. */
123 unsigned char st_shndx
[2]; /* Associated section index. */
124 } Elfalpha_External_Sym
;
126 /* Format of an alpha external ELF dynamic info structure. */
130 unsigned char d_tag
[4]; /* Tag. */
131 unsigned char d_pad
[4]; /* Pad to long word boundary. */
134 unsigned char d_ptr
[8]; /* Pointer value. */
135 unsigned char d_val
[4]; /* Integer value. */
138 } Elfalpha_External_Dyn
;
140 /* Struct to obtain the section pointers for alpha dynamic symbol info. */
142 struct alphacoff_dynsecinfo
144 asection
*sym_sect
; /* Section pointer for .dynsym section. */
145 asection
*str_sect
; /* Section pointer for .dynstr section. */
146 asection
*dyninfo_sect
; /* Section pointer for .dynamic section. */
147 asection
*got_sect
; /* Section pointer for .got section. */
150 /* We are called once per section from read_alphacoff_dynamic_symtab.
151 We need to examine each section we are passed, check to see if it
152 is something we are interested in processing, and if so, stash away
153 some access information for the section. */
156 alphacoff_locate_sections (bfd
*ignore_abfd
, asection
*sectp
, void *sip
)
158 struct alphacoff_dynsecinfo
*si
;
160 si
= (struct alphacoff_dynsecinfo
*) sip
;
162 if (strcmp (sectp
->name
, ".dynsym") == 0)
163 si
->sym_sect
= sectp
;
164 else if (strcmp (sectp
->name
, ".dynstr") == 0)
165 si
->str_sect
= sectp
;
166 else if (strcmp (sectp
->name
, ".dynamic") == 0)
167 si
->dyninfo_sect
= sectp
;
168 else if (strcmp (sectp
->name
, ".got") == 0)
169 si
->got_sect
= sectp
;
172 /* Scan an alpha dynamic symbol table for symbols of interest and add
173 them to the minimal symbol table. */
176 read_alphacoff_dynamic_symtab (struct section_offsets
*section_offsets
,
177 struct objfile
*objfile
)
179 bfd
*abfd
= objfile
->obfd
;
180 struct alphacoff_dynsecinfo si
;
183 char *dyninfo_secptr
;
185 bfd_size_type sym_secsize
;
186 bfd_size_type str_secsize
;
187 bfd_size_type dyninfo_secsize
;
188 bfd_size_type got_secsize
;
192 Elfalpha_External_Sym
*x_symp
;
195 int got_entry_size
= 8;
196 int dt_mips_local_gotno
= -1;
197 int dt_mips_gotsym
= -1;
198 struct cleanup
*cleanups
;
200 /* We currently only know how to handle alpha dynamic symbols. */
201 if (bfd_get_arch (abfd
) != bfd_arch_alpha
)
204 /* Locate the dynamic symbols sections and read them in. */
205 memset ((char *) &si
, 0, sizeof (si
));
206 bfd_map_over_sections (abfd
, alphacoff_locate_sections
, (void *) & si
);
207 if (si
.sym_sect
== NULL
|| si
.str_sect
== NULL
208 || si
.dyninfo_sect
== NULL
|| si
.got_sect
== NULL
)
211 sym_secsize
= bfd_get_section_size (si
.sym_sect
);
212 str_secsize
= bfd_get_section_size (si
.str_sect
);
213 dyninfo_secsize
= bfd_get_section_size (si
.dyninfo_sect
);
214 got_secsize
= bfd_get_section_size (si
.got_sect
);
215 sym_secptr
= (char *) xmalloc (sym_secsize
);
216 cleanups
= make_cleanup (xfree
, sym_secptr
);
217 str_secptr
= (char *) xmalloc (str_secsize
);
218 make_cleanup (xfree
, str_secptr
);
219 dyninfo_secptr
= (char *) xmalloc (dyninfo_secsize
);
220 make_cleanup (xfree
, dyninfo_secptr
);
221 got_secptr
= (char *) xmalloc (got_secsize
);
222 make_cleanup (xfree
, got_secptr
);
224 if (!bfd_get_section_contents (abfd
, si
.sym_sect
, sym_secptr
,
225 (file_ptr
) 0, sym_secsize
))
227 do_cleanups (cleanups
);
230 if (!bfd_get_section_contents (abfd
, si
.str_sect
, str_secptr
,
231 (file_ptr
) 0, str_secsize
))
233 do_cleanups (cleanups
);
236 if (!bfd_get_section_contents (abfd
, si
.dyninfo_sect
, dyninfo_secptr
,
237 (file_ptr
) 0, dyninfo_secsize
))
239 do_cleanups (cleanups
);
242 if (!bfd_get_section_contents (abfd
, si
.got_sect
, got_secptr
,
243 (file_ptr
) 0, got_secsize
))
245 do_cleanups (cleanups
);
249 /* Find the number of local GOT entries and the index for the
250 first dynamic symbol in the GOT. */
251 for (dyninfo_p
= dyninfo_secptr
, dyninfo_end
= dyninfo_p
+ dyninfo_secsize
;
252 dyninfo_p
< dyninfo_end
;
253 dyninfo_p
+= sizeof (Elfalpha_External_Dyn
))
255 Elfalpha_External_Dyn
*x_dynp
= (Elfalpha_External_Dyn
*) dyninfo_p
;
258 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_tag
);
259 if (dyn_tag
== DT_NULL
)
261 else if (dyn_tag
== DT_MIPS_LOCAL_GOTNO
)
263 if (dt_mips_local_gotno
< 0)
265 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
267 else if (dyn_tag
== DT_MIPS_GOTSYM
)
269 if (dt_mips_gotsym
< 0)
271 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
274 if (dt_mips_local_gotno
< 0 || dt_mips_gotsym
< 0)
276 do_cleanups (cleanups
);
280 /* Scan all dynamic symbols and enter them into the minimal symbol
281 table if appropriate. */
282 sym_count
= sym_secsize
/ sizeof (Elfalpha_External_Sym
);
283 stripped
= (bfd_get_symcount (abfd
) == 0);
285 /* Skip first symbol, which is a null dummy. */
286 for (i
= 1, x_symp
= (Elfalpha_External_Sym
*) sym_secptr
+ 1;
293 unsigned char sym_info
;
294 unsigned int sym_shndx
;
296 enum minimal_symbol_type ms_type
;
298 strx
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_symp
->st_name
);
299 if (strx
>= str_secsize
)
301 name
= str_secptr
+ strx
;
302 if (*name
== '\0' || *name
== '.')
305 sym_value
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_symp
->st_value
);
306 sym_info
= bfd_h_get_8 (abfd
, (bfd_byte
*) x_symp
->st_info
);
307 sym_shndx
= bfd_h_get_16 (abfd
, (bfd_byte
*) x_symp
->st_shndx
);
308 if (sym_shndx
>= (SHN_LORESERVE
& 0xffff))
309 sym_shndx
+= SHN_LORESERVE
- (SHN_LORESERVE
& 0xffff);
310 isglobal
= (ELF_ST_BIND (sym_info
) == STB_GLOBAL
);
312 if (sym_shndx
== SHN_UNDEF
)
314 /* Handle undefined functions which are defined in a shared
316 if (ELF_ST_TYPE (sym_info
) != STT_FUNC
317 || ELF_ST_BIND (sym_info
) != STB_GLOBAL
)
320 ms_type
= mst_solib_trampoline
;
322 /* If sym_value is nonzero, it points to the shared library
323 trampoline entry, which is what we are looking for.
325 If sym_value is zero, then we have to get the GOT entry
328 If the GOT entry is nonzero, it represents the quickstart
329 address of the function and we use that as the symbol
332 If the GOT entry is zero, the function address has to be
333 resolved by the runtime loader before the executable is
334 started. We are unable to find any meaningful address
335 for these functions in the executable file, so we skip
339 int got_entry_offset
=
340 (i
- dt_mips_gotsym
+ dt_mips_local_gotno
) * got_entry_size
;
342 if (got_entry_offset
< 0 || got_entry_offset
>= got_secsize
)
346 (bfd_byte
*) (got_secptr
+ got_entry_offset
));
353 /* Symbols defined in the executable itself. We only care
354 about them if this is a stripped executable, otherwise
355 they have been retrieved from the normal symbol table
360 if (sym_shndx
== SHN_MIPS_TEXT
)
365 ms_type
= mst_file_text
;
367 else if (sym_shndx
== SHN_MIPS_DATA
)
372 ms_type
= mst_file_data
;
374 else if (sym_shndx
== SHN_MIPS_ACOMMON
)
379 ms_type
= mst_file_bss
;
381 else if (sym_shndx
== SHN_ABS
)
391 prim_record_minimal_symbol (name
, sym_value
, ms_type
, objfile
);
394 do_cleanups (cleanups
);
397 /* Initialization. */
399 static const struct sym_fns ecoff_sym_fns
=
401 mipscoff_new_init
, /* init anything gbl to entire symtab */
402 mipscoff_symfile_init
, /* read initial info, setup for sym_read() */
403 mipscoff_symfile_read
, /* read a symbol file into symtab */
404 NULL
, /* sym_read_psymbols */
405 mipscoff_symfile_finish
, /* finished with file, cleanup */
406 default_symfile_offsets
, /* dummy FIXME til implem sym reloc */
407 default_symfile_segments
, /* Get segment information from a file. */
409 default_symfile_relocate
, /* Relocate a debug section. */
410 NULL
, /* sym_probe_fns */
414 /* Provide a prototype to silence -Wmissing-prototypes. */
415 void _initialize_mipsread (void);
418 _initialize_mipsread (void)
420 add_symtab_fns (bfd_target_ecoff_flavour
, &ecoff_sym_fns
);