209 lines
7.2 KiB
C
209 lines
7.2 KiB
C
/* Read ELF (Executable and Linking Format) object files for GDB.
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Copyright (C) 1991 Free Software Foundation, Inc.
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Written by Fred Fish at Cygnus Support.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/************************************************************************
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* *
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* NOTICE *
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* *
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* This file is still under construction. When it is complete, this *
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* notice will be removed. Until then, direct any questions or changes *
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* to Fred Fish at Cygnus Support (fnf@cygint) *
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* *
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* FIXME Still needs support for shared libraries. *
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* FIXME Still needs support for core files. *
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* FIXME The ".debug" and ".line" section names are hardwired. *
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* FIXME Still needs support ELF symbol tables (as distinct *
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* from DWARF support). Can use them to build the misc *
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* function vector at least. This is fairly trivial once *
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* bfd is extended to handle ELF symbol tables. *
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* *
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************************************************************************/
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#include <stdio.h>
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#include "defs.h"
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#include "param.h"
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#include "elf-common.h"
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#include "elf-external.h"
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#include "elf-internal.h"
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#include "bfd.h"
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#include "symfile.h"
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#include "symtab.h"
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#include "ansidecl.h"
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extern int EXFUN(strcmp, (CONST char *a, CONST char *b));
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#define STREQ(a,b) (strcmp((a),(b))==0)
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struct elfinfo {
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unsigned int dboffset; /* Offset to dwarf debug section */
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unsigned int dbsize; /* Size of dwarf debug section */
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unsigned int lnoffset; /* Offset to dwarf line number section */
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unsigned int lnsize; /* Size of dwarf line number section */
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};
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/* FIXME - crude hack to resolve undefined global. This function is
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part of support for corefiles, which is not yet implemented. */
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unsigned int
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DEFUN(register_addr, (regno, blockend),
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int regno AND
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int blockend)
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{
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error ("Fetching registers from corefiles unimplemented.");
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}
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/* We are called once per section from elf_symfile_read. We
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need to examine each section we are passed, check to see
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if it is something we are interested in processing, and
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if so, stash away some access information for the section.
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For now we recognize the dwarf debug information sections and
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line number sections from matching their section names. The
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ELF definition is no real help here since it has no direct
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knowledge of DWARF (by design, so any debugging format can be
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used).
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FIXME: The section names should not be hardwired strings. */
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static void
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DEFUN(elf_locate_sections, (abfd, sectp, ei),
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bfd *abfd AND
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asection *sectp AND
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struct elfinfo *ei)
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{
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if (STREQ (sectp -> name, ".debug"))
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{
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ei -> dboffset = sectp -> filepos;
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ei -> dbsize = sectp -> size;
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}
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else if (STREQ (sectp -> name, ".line"))
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{
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ei -> lnoffset = sectp -> filepos;
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ei -> lnsize = sectp -> size;
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}
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}
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/* Scan and build partial symbols for a symbol file.
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We have been initialized by a call to elf_symfile_init, which
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currently does nothing.
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ADDR is the address relative to which the symbols in it are (e.g.
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the base address of the text segment).
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MAINLINE is true if we are reading the main symbol
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table (as opposed to a shared lib or dynamically loaded file).
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This function only does the minimum work necessary for letting the
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user "name" things symbolically; it does not read the entire symtab.
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Instead, it reads the external and static symbols and puts them in partial
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symbol tables. When more extensive information is requested of a
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file, the corresponding partial symbol table is mutated into a full
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fledged symbol table by going back and reading the symbols
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for real. The function dwarf_psymtab_to_symtab() is the function that
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does this for DWARF symbols. */
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static void
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DEFUN(elf_symfile_read, (sf, addr, mainline),
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struct sym_fns *sf AND
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CORE_ADDR addr AND
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int mainline)
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{
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bfd *abfd = sf -> sym_bfd;
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struct elfinfo ei;
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bfd_map_over_sections (abfd, elf_locate_sections, &ei);
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if (ei.dboffset && ei.lnoffset)
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{
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addr = 0; /* FIXME: force address base to zero for now */
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dwarf_build_psymtabs (fileno ((FILE *)(abfd -> iostream)),
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bfd_get_filename (abfd),
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addr, mainline,
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ei.dboffset, ei.dbsize,
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ei.lnoffset, ei.lnsize);
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}
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if (!partial_symtab_list)
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{
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wrap_here ("");
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printf_filtered ("(no debugging symbols found)...");
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wrap_here ("");
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}
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}
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/* Initialize anything that needs initializing when a completely new symbol
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file is specified (not just adding some symbols from another file, e.g. a
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shared library).
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For now at least, we have nothing in particular to do, so this function is
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just a stub. */
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static void
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DEFUN_VOID (elf_new_init)
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{
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}
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/* ELF specific initialization routine for reading symbols.
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It is passed a pointer to a struct sym_fns which contains, among other
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things, the BFD for the file whose symbols are being read, and a slot for
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a pointer to "private data" which we can fill with goodies.
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For now at least, we have nothing in particular to do, so this function is
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just a stub. */
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static void
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DEFUN(elf_symfile_init, (sf),
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struct sym_fns *sf)
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{
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}
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/* Register that we are able to handle ELF object file formats and DWARF
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debugging formats.
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Unlike other object file formats, where the debugging information format
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is implied by the object file format, the ELF object file format and the
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DWARF debugging information format are two distinct, and potentially
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separate entities. I.E. it is perfectly possible to have ELF objects
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with debugging formats other than DWARF. And it is conceivable that the
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DWARF debugging format might be used with another object file format,
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like COFF, by simply using COFF's custom section feature.
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GDB, and to a lesser extent BFD, should support the notion of separate
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object file formats and debugging information formats. For now, we just
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use "elf" in the same sense as "a.out" or "coff", to imply both the ELF
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object file format and the DWARF debugging format. */
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static struct sym_fns elf_sym_fns = {
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"elf", /* sym_name: name or name prefix of BFD target type */
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3, /* sym_namelen: number of significant sym_name chars */
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elf_new_init, /* sym_new_init: init anything gbl to entire symtab */
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elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */
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elf_symfile_read, /* sym_read: read a symbol file into symtab */
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NULL, /* sym_bfd: accessor for symbol file being read */
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NULL, /* sym_private: sym_init & sym_read shared info */
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NULL /* next: pointer to next struct sym_fns */
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};
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void
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DEFUN_VOID (_initialize_elfread)
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{
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add_symtab_fns (&elf_sym_fns);
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}
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