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"
38 #include "elf/common.h"
39 #include "elf/internal.h"
43 read_alphacoff_dynamic_symtab (minimal_symbol_reader
&,
44 struct objfile
*objfile
);
46 /* Initialize anything that needs initializing when a completely new
47 symbol file is specified (not just adding some symbols from another
48 file, e.g. a shared library). */
51 mipscoff_new_init (struct objfile
*ignore
)
53 stabsread_new_init ();
56 /* Initialize to read a symbol file (nothing to do). */
59 mipscoff_symfile_init (struct objfile
*objfile
)
63 /* Read a symbol file from a file. */
66 mipscoff_symfile_read (struct objfile
*objfile
, symfile_add_flags symfile_flags
)
68 bfd
*abfd
= objfile
->obfd
.get ();
70 minimal_symbol_reader
reader (objfile
);
72 /* Now that the executable file is positioned at symbol table,
73 process it and define symbols accordingly. */
75 if (!((*ecoff_backend (abfd
)->debug_swap
.read_debug_info
)
76 (abfd
, NULL
, &ecoff_data (abfd
)->debug_info
)))
77 error (_("Error reading symbol table: %s"), bfd_errmsg (bfd_get_error ()));
79 mdebug_build_psymtabs (reader
, objfile
, &ecoff_backend (abfd
)->debug_swap
,
80 &ecoff_data (abfd
)->debug_info
);
82 /* Add alpha coff dynamic symbols. */
84 read_alphacoff_dynamic_symtab (reader
, objfile
);
86 /* Install any minimal symbols that have been collected as the current
87 minimal symbols for this objfile. */
92 /* Perform any local cleanups required when we are done with a
93 particular objfile. */
96 mipscoff_symfile_finish (struct objfile
*objfile
)
100 /* Alpha OSF/1 encapsulates the dynamic symbols in ELF format in a
101 standard COFF section. The ELF format for the symbols differs from
102 the format defined in elf/external.h. It seems that a normal ELF
103 32-bit format is used, and the representation only changes because
104 longs are 64-bit on the alpha. In addition, the handling of
105 text/data section indices for symbols is different from the ELF
106 ABI. As the BFD linker currently does not support dynamic linking
107 on the alpha, there seems to be no reason to pollute BFD with
108 another mixture of object file formats for now. */
110 /* Format of an alpha external ELF symbol. */
114 unsigned char st_name
[4]; /* Symbol name, index in string table. */
115 unsigned char st_pad
[4]; /* Pad to long word boundary. */
116 unsigned char st_value
[8]; /* Value of the symbol. */
117 unsigned char st_size
[4]; /* Associated symbol size. */
118 unsigned char st_info
[1]; /* Type and binding attributes. */
119 unsigned char st_other
[1]; /* No defined meaning, 0. */
120 unsigned char st_shndx
[2]; /* Associated section index. */
121 } Elfalpha_External_Sym
;
123 /* Format of an alpha external ELF dynamic info structure. */
127 unsigned char d_tag
[4]; /* Tag. */
128 unsigned char d_pad
[4]; /* Pad to long word boundary. */
131 unsigned char d_ptr
[8]; /* Pointer value. */
132 unsigned char d_val
[4]; /* Integer value. */
135 } Elfalpha_External_Dyn
;
137 /* Struct to obtain the section pointers for alpha dynamic symbol info. */
139 struct alphacoff_dynsecinfo
141 asection
*sym_sect
; /* Section pointer for .dynsym section. */
142 asection
*str_sect
; /* Section pointer for .dynstr section. */
143 asection
*dyninfo_sect
; /* Section pointer for .dynamic section. */
144 asection
*got_sect
; /* Section pointer for .got section. */
147 /* We are called once per section from read_alphacoff_dynamic_symtab.
148 We need to examine each section we are passed, check to see if it
149 is something we are interested in processing, and if so, stash away
150 some access information for the section. */
153 alphacoff_locate_sections (bfd
*ignore_abfd
, asection
*sectp
, void *sip
)
155 struct alphacoff_dynsecinfo
*si
;
157 si
= (struct alphacoff_dynsecinfo
*) sip
;
159 if (strcmp (sectp
->name
, ".dynsym") == 0)
160 si
->sym_sect
= sectp
;
161 else if (strcmp (sectp
->name
, ".dynstr") == 0)
162 si
->str_sect
= sectp
;
163 else if (strcmp (sectp
->name
, ".dynamic") == 0)
164 si
->dyninfo_sect
= sectp
;
165 else if (strcmp (sectp
->name
, ".got") == 0)
166 si
->got_sect
= sectp
;
169 /* Scan an alpha dynamic symbol table for symbols of interest and add
170 them to the minimal symbol table. */
173 read_alphacoff_dynamic_symtab (minimal_symbol_reader
&reader
,
174 struct objfile
*objfile
)
176 bfd
*abfd
= objfile
->obfd
.get ();
177 struct alphacoff_dynsecinfo si
;
181 Elfalpha_External_Sym
*x_symp
;
183 gdb_byte
*dyninfo_end
;
184 int got_entry_size
= 8;
185 int dt_mips_local_gotno
= -1;
186 int dt_mips_gotsym
= -1;
188 /* We currently only know how to handle alpha dynamic symbols. */
189 if (bfd_get_arch (abfd
) != bfd_arch_alpha
)
192 /* Locate the dynamic symbols sections and read them in. */
193 memset ((char *) &si
, 0, sizeof (si
));
194 bfd_map_over_sections (abfd
, alphacoff_locate_sections
, (void *) & si
);
195 if (si
.sym_sect
== NULL
|| si
.str_sect
== NULL
196 || si
.dyninfo_sect
== NULL
|| si
.got_sect
== NULL
)
199 gdb::byte_vector
sym_sec (bfd_section_size (si
.sym_sect
));
200 gdb::byte_vector
str_sec (bfd_section_size (si
.str_sect
));
201 gdb::byte_vector
dyninfo_sec (bfd_section_size (si
.dyninfo_sect
));
202 gdb::byte_vector
got_sec (bfd_section_size (si
.got_sect
));
204 if (!bfd_get_section_contents (abfd
, si
.sym_sect
, sym_sec
.data (),
205 (file_ptr
) 0, sym_sec
.size ()))
207 if (!bfd_get_section_contents (abfd
, si
.str_sect
, str_sec
.data (),
208 (file_ptr
) 0, str_sec
.size ()))
210 if (!bfd_get_section_contents (abfd
, si
.dyninfo_sect
, dyninfo_sec
.data (),
211 (file_ptr
) 0, dyninfo_sec
.size ()))
213 if (!bfd_get_section_contents (abfd
, si
.got_sect
, got_sec
.data (),
214 (file_ptr
) 0, got_sec
.size ()))
217 /* Find the number of local GOT entries and the index for the
218 first dynamic symbol in the GOT. */
219 for ((dyninfo_p
= dyninfo_sec
.data (),
220 dyninfo_end
= dyninfo_p
+ dyninfo_sec
.size ());
221 dyninfo_p
< dyninfo_end
;
222 dyninfo_p
+= sizeof (Elfalpha_External_Dyn
))
224 Elfalpha_External_Dyn
*x_dynp
= (Elfalpha_External_Dyn
*) dyninfo_p
;
227 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_tag
);
228 if (dyn_tag
== DT_NULL
)
230 else if (dyn_tag
== DT_MIPS_LOCAL_GOTNO
)
232 if (dt_mips_local_gotno
< 0)
234 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
236 else if (dyn_tag
== DT_MIPS_GOTSYM
)
238 if (dt_mips_gotsym
< 0)
240 = bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp
->d_un
.d_val
);
243 if (dt_mips_local_gotno
< 0 || dt_mips_gotsym
< 0)
246 /* Scan all dynamic symbols and enter them into the minimal symbol
247 table if appropriate. */
248 sym_count
= sym_sec
.size () / sizeof (Elfalpha_External_Sym
);
249 stripped
= (bfd_get_symcount (abfd
) == 0);
251 /* Skip first symbol, which is a null dummy. */
252 for (i
= 1, x_symp
= (Elfalpha_External_Sym
*) sym_sec
.data () + 1;
259 unsigned char sym_info
;
260 unsigned int sym_shndx
;
262 enum minimal_symbol_type ms_type
;
264 strx
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_symp
->st_name
);
265 if (strx
>= str_sec
.size ())
267 name
= (char *) (str_sec
.data () + strx
);
268 if (*name
== '\0' || *name
== '.')
271 sym_value
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_symp
->st_value
);
272 sym_info
= bfd_h_get_8 (abfd
, (bfd_byte
*) x_symp
->st_info
);
273 sym_shndx
= bfd_h_get_16 (abfd
, (bfd_byte
*) x_symp
->st_shndx
);
274 if (sym_shndx
>= (SHN_LORESERVE
& 0xffff))
275 sym_shndx
+= SHN_LORESERVE
- (SHN_LORESERVE
& 0xffff);
276 isglobal
= (ELF_ST_BIND (sym_info
) == STB_GLOBAL
);
278 if (sym_shndx
== SHN_UNDEF
)
280 /* Handle undefined functions which are defined in a shared
282 if (ELF_ST_TYPE (sym_info
) != STT_FUNC
283 || ELF_ST_BIND (sym_info
) != STB_GLOBAL
)
286 ms_type
= mst_solib_trampoline
;
288 /* If sym_value is nonzero, it points to the shared library
289 trampoline entry, which is what we are looking for.
291 If sym_value is zero, then we have to get the GOT entry
294 If the GOT entry is nonzero, it represents the quickstart
295 address of the function and we use that as the symbol
298 If the GOT entry is zero, the function address has to be
299 resolved by the runtime loader before the executable is
300 started. We are unable to find any meaningful address
301 for these functions in the executable file, so we skip
305 int got_entry_offset
=
306 (i
- dt_mips_gotsym
+ dt_mips_local_gotno
) * got_entry_size
;
308 if (got_entry_offset
< 0
309 || got_entry_offset
>= got_sec
.size ())
313 (bfd_byte
*) (got_sec
.data ()
314 + got_entry_offset
));
321 /* Symbols defined in the executable itself. We only care
322 about them if this is a stripped executable, otherwise
323 they have been retrieved from the normal symbol table
328 if (sym_shndx
== SHN_MIPS_TEXT
)
333 ms_type
= mst_file_text
;
335 else if (sym_shndx
== SHN_MIPS_DATA
)
340 ms_type
= mst_file_data
;
342 else if (sym_shndx
== SHN_MIPS_ACOMMON
)
347 ms_type
= mst_file_bss
;
349 else if (sym_shndx
== SHN_ABS
)
359 reader
.record (name
, unrelocated_addr (sym_value
), ms_type
);
363 /* Initialization. */
365 static const struct sym_fns ecoff_sym_fns
=
367 mipscoff_new_init
, /* init anything gbl to entire symtab */
368 mipscoff_symfile_init
, /* read initial info, setup for sym_read() */
369 mipscoff_symfile_read
, /* read a symbol file into symtab */
370 mipscoff_symfile_finish
, /* finished with file, cleanup */
371 default_symfile_offsets
, /* dummy FIXME til implem sym reloc */
372 default_symfile_segments
, /* Get segment information from a file. */
374 default_symfile_relocate
, /* Relocate a debug section. */
375 NULL
, /* sym_probe_fns */
378 void _initialize_mipsread ();
380 _initialize_mipsread ()
382 add_symtab_fns (bfd_target_ecoff_flavour
, &ecoff_sym_fns
);