1991-10-24 12:28:54 +01:00
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/* 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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1991-12-01 07:47:23 +01:00
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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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1991-10-24 12:28:54 +01:00
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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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1991-11-09 11:50:07 +01:00
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extern int EXFUN (strcmp, (CONST char *a, CONST char *b));
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extern int EXFUN (dwarf_build_psymtabs,
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(int desc, char *filename, CORE_ADDR addr, int mainline,
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unsigned int dbfoff, unsigned int dbsize, unsigned int lnoffset,
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unsigned int lnsize, struct objfile *objfile));
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1991-10-24 12:28:54 +01:00
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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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/* 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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1991-12-16 21:57:28 +01:00
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char *
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DEFUN(elf_interpreter, (abfd),
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bfd *abfd)
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{
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sec_ptr interp_sec;
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unsigned size;
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char *interp = NULL;
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interp_sec = bfd_get_section_by_name (abfd, ".interp");
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if (interp_sec)
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{
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size = bfd_section_size (abfd, interp_sec);
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interp = alloca (size);
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if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0,
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size))
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{
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interp = savestring (interp, size - 1);
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}
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else
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{
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interp = NULL;
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}
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}
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return (interp);
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}
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1991-11-15 04:36:45 +01:00
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/*
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LOCAL FUNCTION
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record_misc_function -- add entry to miscellaneous function vector
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SYNOPSIS
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static void record_misc_function (char *name, CORE_ADDR address)
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DESCRIPTION
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Given a pointer to the name of a symbol that should be added to the
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miscellaneous function vector, and the address associated with that
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symbol, records this information for later use in building the
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miscellaneous function vector.
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NOTES
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FIXME: For now we just use mf_unknown as the type. This should be
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fixed.
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*/
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static void
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1991-12-16 21:57:28 +01:00
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DEFUN(record_misc_function, (name, address, mf_type),
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char *name AND CORE_ADDR address AND enum misc_function_type mf_type)
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1991-11-15 04:36:45 +01:00
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{
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prim_record_misc_function (obsavestring (name, strlen (name)), address,
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1991-12-16 21:57:28 +01:00
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mf_type);
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1991-11-15 04:36:45 +01:00
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}
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1991-12-16 21:57:28 +01:00
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/*
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LOCAL FUNCTION
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elf_symtab_read -- read the symbol table of an ELF file
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SYNOPSIS
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void elf_symtab_read (bfd *abfd, CORE_ADDR addr, int mainline)
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DESCRIPTION
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Given an open bfd, a base address to relocate symbols to, and a
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flag that specifies whether or not this bfd is for an executable
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or not (may be shared library for example), add all the global
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function and data symbols to the miscellaneous function vector.
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*/
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1991-11-15 04:36:45 +01:00
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static void
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1991-12-16 21:57:28 +01:00
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DEFUN (elf_symtab_read, (abfd, addr, mainline),
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1991-11-15 04:36:45 +01:00
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bfd *abfd AND
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1991-12-16 21:57:28 +01:00
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CORE_ADDR addr AND
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int mainline)
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1991-11-15 04:36:45 +01:00
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{
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unsigned int storage_needed;
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asymbol *sym;
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asymbol **symbol_table;
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unsigned int number_of_symbols;
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unsigned int i;
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struct cleanup *back_to;
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1991-12-16 21:57:28 +01:00
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CORE_ADDR symaddr;
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enum misc_function_type mf_type;
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1991-11-15 04:36:45 +01:00
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storage_needed = get_symtab_upper_bound (abfd);
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if (storage_needed > 0)
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{
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symbol_table = (asymbol **) bfd_xmalloc (storage_needed);
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back_to = make_cleanup (free, symbol_table);
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number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
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for (i = 0; i < number_of_symbols; i++)
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{
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sym = *symbol_table++;
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/* Select global symbols that are defined in a specific section
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or are absolute. */
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if (sym -> flags & BSF_GLOBAL
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&& ((sym -> section != NULL) || (sym -> flags & BSF_ABSOLUTE)))
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{
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1991-12-16 21:57:28 +01:00
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symaddr = sym -> value;
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if (!mainline)
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{
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/* Relocate all symbols by base address */
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symaddr += addr;
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}
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/* For non-absolute symbols, use the type of the section
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they are relative to, to intuit text/data. Bfd provides
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no way of figuring this out for absolute symbols. */
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if (sym -> section && (sym -> section -> flags & SEC_CODE))
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{
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mf_type = mf_text;
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}
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else if (sym -> section && (sym -> section -> flags & SEC_DATA))
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{
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mf_type = mf_data;
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}
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else
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{
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mf_type = mf_unknown;
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}
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record_misc_function ((char *) sym -> name, symaddr, mf_type);
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1991-11-15 04:36:45 +01:00
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}
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}
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do_cleanups (back_to);
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}
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}
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1991-10-24 12:28:54 +01:00
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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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1991-11-15 04:36:45 +01:00
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does this for DWARF symbols.
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Note that ELF files have a "minimal" symbol table, which looks a lot
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like a COFF symbol table, but has only the minimal information necessary
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for linking. We process this also, and just use the information to
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add to the misc function vector. This gives us some minimal debugging
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capability even for files compiled without -g.
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*/
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1991-10-24 12:28:54 +01:00
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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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1991-11-09 11:50:07 +01:00
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bfd *abfd = sf->objfile->obfd;
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1991-10-24 12:28:54 +01:00
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struct elfinfo ei;
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1991-11-15 04:36:45 +01:00
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struct cleanup *back_to;
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1991-10-24 12:28:54 +01:00
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1991-11-15 04:36:45 +01:00
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init_misc_bunches ();
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back_to = make_cleanup (discard_misc_bunches, 0);
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/* Process the normal ELF symbol table first. */
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1991-12-16 21:57:28 +01:00
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elf_symtab_read (abfd, addr, mainline);
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1991-11-15 04:36:45 +01:00
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/* Now process the DWARF debugging information, which is contained in
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special ELF sections. We first have to find them... */
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(void) memset ((char *) &ei, 0, sizeof (ei));
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1991-10-24 12:28:54 +01:00
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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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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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1991-11-09 11:50:07 +01:00
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ei.lnoffset, ei.lnsize, sf->objfile);
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1991-10-24 12:28:54 +01:00
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}
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1991-11-15 04:36:45 +01:00
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1991-10-24 12:28:54 +01:00
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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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1991-11-15 04:36:45 +01:00
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/* Go over the miscellaneous functions and install them in the
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miscellaneous function vector. */
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condense_misc_bunches (!mainline);
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do_cleanups (back_to);
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1991-10-24 12:28:54 +01:00
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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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