1 /* Read a symbol table in MIPS' format (Third-Eye).
3 Copyright (C) 1986-2023 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
30 #include "stabsread.h"
31 #include "mdebugread.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 (minimal_symbol_reader
&,
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 ();
58 /* Initialize to read a symbol file (nothing to do). */
61 mipscoff_symfile_init (struct objfile
*objfile
)
65 /* Read a symbol file from a file. */
68 mipscoff_symfile_read (struct objfile
*objfile
, symfile_add_flags symfile_flags
)
70 bfd
*abfd
= objfile
->obfd
.get ();
72 minimal_symbol_reader
reader (objfile
);
74 /* Now that the executable file is positioned at symbol table,
75 process it and define symbols accordingly. */
77 if (!((*ecoff_backend (abfd
)->debug_swap
.read_debug_info
)
78 (abfd
, NULL
, &ecoff_data (abfd
)->debug_info
)))
79 error (_("Error reading symbol table: %s"), bfd_errmsg (bfd_get_error ()));
81 mdebug_build_psymtabs (reader
, objfile
, &ecoff_backend (abfd
)->debug_swap
,
82 &ecoff_data (abfd
)->debug_info
);
84 /* Add alpha coff dynamic symbols. */
86 read_alphacoff_dynamic_symtab (reader
, objfile
);
88 /* Install any minimal symbols that have been collected as the current
89 minimal symbols for this objfile. */
94 /* Perform any local cleanups required when we are done with a
95 particular objfile. */
98 mipscoff_symfile_finish (struct objfile
*objfile
)
102 /* Alpha OSF/1 encapsulates the dynamic symbols in ELF format in a
103 standard COFF section. The ELF format for the symbols differs from
104 the format defined in elf/external.h. It seems that a normal ELF
105 32-bit format is used, and the representation only changes because
106 longs are 64-bit on the alpha. In addition, the handling of
107 text/data section indices for symbols is different from the ELF
108 ABI. As the BFD linker currently does not support dynamic linking
109 on the alpha, there seems to be no reason to pollute BFD with
110 another mixture of object file formats for now. */
112 /* Format of an alpha external ELF symbol. */
116 unsigned char st_name
[4]; /* Symbol name, index in string table. */
117 unsigned char st_pad
[4]; /* Pad to long word boundary. */
118 unsigned char st_value
[8]; /* Value of the symbol. */
119 unsigned char st_size
[4]; /* Associated symbol size. */
120 unsigned char st_info
[1]; /* Type and binding attributes. */
121 unsigned char st_other
[1]; /* No defined meaning, 0. */
122 unsigned char st_shndx
[2]; /* Associated section index. */
123 } Elfalpha_External_Sym
;
125 /* Format of an alpha external ELF dynamic info structure. */
129 unsigned char d_tag
[4]; /* Tag. */
130 unsigned char d_pad
[4]; /* Pad to long word boundary. */
133 unsigned char d_ptr
[8]; /* Pointer value. */
134 unsigned char d_val
[4]; /* Integer value. */
137 } Elfalpha_External_Dyn
;
139 /* Struct to obtain the section pointers for alpha dynamic symbol info. */
141 struct alphacoff_dynsecinfo
143 asection
*sym_sect
; /* Section pointer for .dynsym section. */
144 asection
*str_sect
; /* Section pointer for .dynstr section. */
145 asection
*dyninfo_sect
; /* Section pointer for .dynamic section. */
146 asection
*got_sect
; /* Section pointer for .got section. */
149 /* We are called once per section from read_alphacoff_dynamic_symtab.
150 We need to examine each section we are passed, check to see if it
151 is something we are interested in processing, and if so, stash away
152 some access information for the section. */
155 alphacoff_locate_sections (bfd
*ignore_abfd
, asection
*sectp
, void *sip
)
157 struct alphacoff_dynsecinfo
*si
;
159 si
= (struct alphacoff_dynsecinfo
*) sip
;
161 if (strcmp (sectp
->name
, ".dynsym") == 0)
162 si
->sym_sect
= sectp
;
163 else if (strcmp (sectp
->name
, ".dynstr") == 0)
164 si
->str_sect
= sectp
;
165 else if (strcmp (sectp
->name
, ".dynamic") == 0)
166 si
->dyninfo_sect
= sectp
;
167 else if (strcmp (sectp
->name
, ".got") == 0)
168 si
->got_sect
= sectp
;
171 /* Scan an alpha dynamic symbol table for symbols of interest and add
172 them to the minimal symbol table. */
175 read_alphacoff_dynamic_symtab (minimal_symbol_reader
&reader
,
176 struct objfile
*objfile
)
178 bfd
*abfd
= objfile
->obfd
.get ();
179 struct alphacoff_dynsecinfo si
;
183 Elfalpha_External_Sym
*x_symp
;
185 gdb_byte
*dyninfo_end
;
186 int got_entry_size
= 8;
187 int dt_mips_local_gotno
= -1;
188 int dt_mips_gotsym
= -1;
190 /* We currently only know how to handle alpha dynamic symbols. */
191 if (bfd_get_arch (abfd
) != bfd_arch_alpha
)
194 /* Locate the dynamic symbols sections and read them in. */
195 memset ((char *) &si
, 0, sizeof (si
));
196 bfd_map_over_sections (abfd
, alphacoff_locate_sections
, (void *) & si
);
197 if (si
.sym_sect
== NULL
|| si
.str_sect
== NULL
198 || si
.dyninfo_sect
== NULL
|| si
.got_sect
== NULL
)
201 gdb::byte_vector
sym_sec (bfd_section_size (si
.sym_sect
));
202 gdb::byte_vector
str_sec (bfd_section_size (si
.str_sect
));
203 gdb::byte_vector
dyninfo_sec (bfd_section_size (si
.dyninfo_sect
));
204 gdb::byte_vector
got_sec (bfd_section_size (si
.got_sect
));
206 if (!bfd_get_section_contents (abfd
, si
.sym_sect
, sym_sec
.data (),
207 (file_ptr
) 0, sym_sec
.size ()))
209 if (!bfd_get_section_contents (abfd
, si
.str_sect
, str_sec
.data (),
210 (file_ptr
) 0, str_sec
.size ()))
212 if (!bfd_get_section_contents (abfd
, si
.dyninfo_sect
, dyninfo_sec
.data (),
213 (file_ptr
) 0, dyninfo_sec
.size ()))
215 if (!bfd_get_section_contents (abfd
, si
.got_sect
, got_sec
.data (),
216 (file_ptr
) 0, got_sec
.size ()))
219 /* Find the number of local GOT entries and the index for the
220 first dynamic symbol in the GOT. */
221 for ((dyninfo_p
= dyninfo_sec
.data (),
222 dyninfo_end
= dyninfo_p
+ dyninfo_sec
.size ());
223 dyninfo_p
< dyninfo_end
;
224 dyninfo_p
+= sizeof (Elfalpha_External_Dyn
))
226 Elfalpha_External_Dyn
*x_dynp
= (Elfalpha_External_Dyn
*) dyninfo_p
;
229 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_tag
);
230 if (dyn_tag
== DT_NULL
)
232 else if (dyn_tag
== DT_MIPS_LOCAL_GOTNO
)
234 if (dt_mips_local_gotno
< 0)
236 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
238 else if (dyn_tag
== DT_MIPS_GOTSYM
)
240 if (dt_mips_gotsym
< 0)
242 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
245 if (dt_mips_local_gotno
< 0 || dt_mips_gotsym
< 0)
248 /* Scan all dynamic symbols and enter them into the minimal symbol
249 table if appropriate. */
250 sym_count
= sym_sec
.size () / sizeof (Elfalpha_External_Sym
);
251 stripped
= (bfd_get_symcount (abfd
) == 0);
253 /* Skip first symbol, which is a null dummy. */
254 for (i
= 1, x_symp
= (Elfalpha_External_Sym
*) sym_sec
.data () + 1;
261 unsigned char sym_info
;
262 unsigned int sym_shndx
;
264 enum minimal_symbol_type ms_type
;
266 strx
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_symp
->st_name
);
267 if (strx
>= str_sec
.size ())
269 name
= (char *) (str_sec
.data () + strx
);
270 if (*name
== '\0' || *name
== '.')
273 sym_value
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_symp
->st_value
);
274 sym_info
= bfd_h_get_8 (abfd
, (bfd_byte
*) x_symp
->st_info
);
275 sym_shndx
= bfd_h_get_16 (abfd
, (bfd_byte
*) x_symp
->st_shndx
);
276 if (sym_shndx
>= (SHN_LORESERVE
& 0xffff))
277 sym_shndx
+= SHN_LORESERVE
- (SHN_LORESERVE
& 0xffff);
278 isglobal
= (ELF_ST_BIND (sym_info
) == STB_GLOBAL
);
280 if (sym_shndx
== SHN_UNDEF
)
282 /* Handle undefined functions which are defined in a shared
284 if (ELF_ST_TYPE (sym_info
) != STT_FUNC
285 || ELF_ST_BIND (sym_info
) != STB_GLOBAL
)
288 ms_type
= mst_solib_trampoline
;
290 /* If sym_value is nonzero, it points to the shared library
291 trampoline entry, which is what we are looking for.
293 If sym_value is zero, then we have to get the GOT entry
296 If the GOT entry is nonzero, it represents the quickstart
297 address of the function and we use that as the symbol
300 If the GOT entry is zero, the function address has to be
301 resolved by the runtime loader before the executable is
302 started. We are unable to find any meaningful address
303 for these functions in the executable file, so we skip
307 int got_entry_offset
=
308 (i
- dt_mips_gotsym
+ dt_mips_local_gotno
) * got_entry_size
;
310 if (got_entry_offset
< 0
311 || got_entry_offset
>= got_sec
.size ())
315 (bfd_byte
*) (got_sec
.data ()
316 + got_entry_offset
));
323 /* Symbols defined in the executable itself. We only care
324 about them if this is a stripped executable, otherwise
325 they have been retrieved from the normal symbol table
330 if (sym_shndx
== SHN_MIPS_TEXT
)
335 ms_type
= mst_file_text
;
337 else if (sym_shndx
== SHN_MIPS_DATA
)
342 ms_type
= mst_file_data
;
344 else if (sym_shndx
== SHN_MIPS_ACOMMON
)
349 ms_type
= mst_file_bss
;
351 else if (sym_shndx
== SHN_ABS
)
361 reader
.record (name
, sym_value
, ms_type
);
365 /* Initialization. */
367 static const struct sym_fns ecoff_sym_fns
=
369 mipscoff_new_init
, /* init anything gbl to entire symtab */
370 mipscoff_symfile_init
, /* read initial info, setup for sym_read() */
371 mipscoff_symfile_read
, /* read a symbol file into symtab */
372 mipscoff_symfile_finish
, /* finished with file, cleanup */
373 default_symfile_offsets
, /* dummy FIXME til implem sym reloc */
374 default_symfile_segments
, /* Get segment information from a file. */
376 default_symfile_relocate
, /* Relocate a debug section. */
377 NULL
, /* sym_probe_fns */
380 void _initialize_mipsread ();
382 _initialize_mipsread ()
384 add_symtab_fns (bfd_target_ecoff_flavour
, &ecoff_sym_fns
);