1 /* Read ELF (Executable and Linking Format) object files for GDB.
2 Copyright (C) 1991 Free Software Foundation, Inc.
3 Written by Fred Fish at Cygnus Support.
5 This file is part of GDB.
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.
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.
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. */
21 /************************************************************************
25 * This file is still under construction. When it is complete, this *
26 * notice will be removed. Until then, direct any questions or changes *
27 * to Fred Fish at Cygnus Support (fnf@cygint) *
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. *
32 * FIXME Still needs support ELF symbol tables (as distinct *
33 * from DWARF support). Can use them to build the misc *
34 * function vector at least. This is fairly trivial once *
35 * bfd is extended to handle ELF symbol tables. *
37 ************************************************************************/
43 #include "elf-common.h"
44 #include "elf-external.h"
45 #include "elf-internal.h"
51 extern int EXFUN(strcmp
, (CONST
char *a
, CONST
char *b
));
52 #define STREQ(a,b) (strcmp((a),(b))==0)
55 unsigned int dboffset
; /* Offset to dwarf debug section */
56 unsigned int dbsize
; /* Size of dwarf debug section */
57 unsigned int lnoffset
; /* Offset to dwarf line number section */
58 unsigned int lnsize
; /* Size of dwarf line number section */
61 /* FIXME - crude hack to resolve undefined global. This function is
62 part of support for corefiles, which is not yet implemented. */
65 DEFUN(register_addr
, (regno
, blockend
),
69 error ("Fetching registers from corefiles unimplemented.");
72 /* We are called once per section from elf_symfile_read. We
73 need to examine each section we are passed, check to see
74 if it is something we are interested in processing, and
75 if so, stash away some access information for the section.
77 For now we recognize the dwarf debug information sections and
78 line number sections from matching their section names. The
79 ELF definition is no real help here since it has no direct
80 knowledge of DWARF (by design, so any debugging format can be
83 FIXME: The section names should not be hardwired strings. */
86 DEFUN(elf_locate_sections
, (abfd
, sectp
, ei
),
91 if (STREQ (sectp
-> name
, ".debug"))
93 ei
-> dboffset
= sectp
-> filepos
;
94 ei
-> dbsize
= sectp
-> size
;
96 else if (STREQ (sectp
-> name
, ".line"))
98 ei
-> lnoffset
= sectp
-> filepos
;
99 ei
-> lnsize
= sectp
-> size
;
103 /* Scan and build partial symbols for a symbol file.
104 We have been initialized by a call to elf_symfile_init, which
105 currently does nothing.
107 ADDR is the address relative to which the symbols in it are (e.g.
108 the base address of the text segment).
110 MAINLINE is true if we are reading the main symbol
111 table (as opposed to a shared lib or dynamically loaded file).
113 This function only does the minimum work necessary for letting the
114 user "name" things symbolically; it does not read the entire symtab.
115 Instead, it reads the external and static symbols and puts them in partial
116 symbol tables. When more extensive information is requested of a
117 file, the corresponding partial symbol table is mutated into a full
118 fledged symbol table by going back and reading the symbols
119 for real. The function dwarf_psymtab_to_symtab() is the function that
120 does this for DWARF symbols. */
123 DEFUN(elf_symfile_read
, (sf
, addr
, mainline
),
124 struct sym_fns
*sf AND
128 bfd
*abfd
= sf
-> sym_bfd
;
131 bfd_map_over_sections (abfd
, elf_locate_sections
, &ei
);
132 if (ei
.dboffset
&& ei
.lnoffset
)
134 addr
= 0; /* FIXME: force address base to zero for now */
135 dwarf_build_psymtabs (fileno ((FILE *)(abfd
-> iostream
)),
136 bfd_get_filename (abfd
),
138 ei
.dboffset
, ei
.dbsize
,
139 ei
.lnoffset
, ei
.lnsize
);
141 if (!partial_symtab_list
)
144 printf_filtered ("(no debugging symbols found)...");
149 /* Initialize anything that needs initializing when a completely new symbol
150 file is specified (not just adding some symbols from another file, e.g. a
153 For now at least, we have nothing in particular to do, so this function is
157 DEFUN_VOID (elf_new_init
)
161 /* ELF specific initialization routine for reading symbols.
163 It is passed a pointer to a struct sym_fns which contains, among other
164 things, the BFD for the file whose symbols are being read, and a slot for
165 a pointer to "private data" which we can fill with goodies.
167 For now at least, we have nothing in particular to do, so this function is
171 DEFUN(elf_symfile_init
, (sf
),
177 /* Register that we are able to handle ELF object file formats and DWARF
180 Unlike other object file formats, where the debugging information format
181 is implied by the object file format, the ELF object file format and the
182 DWARF debugging information format are two distinct, and potentially
183 separate entities. I.E. it is perfectly possible to have ELF objects
184 with debugging formats other than DWARF. And it is conceivable that the
185 DWARF debugging format might be used with another object file format,
186 like COFF, by simply using COFF's custom section feature.
188 GDB, and to a lesser extent BFD, should support the notion of separate
189 object file formats and debugging information formats. For now, we just
190 use "elf" in the same sense as "a.out" or "coff", to imply both the ELF
191 object file format and the DWARF debugging format. */
193 static struct sym_fns elf_sym_fns
= {
194 "elf", /* sym_name: name or name prefix of BFD target type */
195 3, /* sym_namelen: number of significant sym_name chars */
196 elf_new_init
, /* sym_new_init: init anything gbl to entire symtab */
197 elf_symfile_init
, /* sym_init: read initial info, setup for sym_read() */
198 elf_symfile_read
, /* sym_read: read a symbol file into symtab */
199 NULL
, /* sym_bfd: accessor for symbol file being read */
200 NULL
, /* sym_private: sym_init & sym_read shared info */
201 NULL
/* next: pointer to next struct sym_fns */
205 DEFUN_VOID (_initialize_elfread
)
207 add_symtab_fns (&elf_sym_fns
);
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