d747e0af3d
* All GDB files that #include defs.h: Removed stdio.h. (defs.h): #include stdio.h. This has been tested by building GDBs for all targets hosted on Sun4. None of the build problems were related to stdio.h inclusion. (n.b. many configurations don't build for other reasons.)
378 lines
11 KiB
C
378 lines
11 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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* *
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************************************************************************/
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#include "defs.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 "symtab.h"
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#include "symfile.h"
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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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static void
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elf_symfile_init PARAMS ((struct sym_fns *));
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static void
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elf_new_init PARAMS ((void));
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static void
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elf_symfile_read PARAMS ((struct sym_fns *, CORE_ADDR, int));
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static void
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elf_symtab_read PARAMS ((bfd *, CORE_ADDR, int, struct objfile *));
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static void
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record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type,
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struct objfile *));
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static void
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elf_locate_sections PARAMS ((bfd *, asection *, PTR));
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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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elf_locate_sections (abfd, sectp, eip)
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bfd *abfd;
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asection *sectp;
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PTR eip;
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{
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register struct elfinfo *ei;
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ei = (struct elfinfo *) eip;
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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 = bfd_get_section_size_before_reloc (sectp);
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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 = bfd_get_section_size_before_reloc (sectp);
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}
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}
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#if 0 /* Currently unused */
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char *
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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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#endif
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/*
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LOCAL FUNCTION
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record_minimal_symbol -- add entry to minimal symbol table
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SYNOPSIS
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static void record_minimal_symbol (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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minimal symbol table and the address associated with that symbol, records
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this information for later use in building the minimal symbol table.
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*/
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static void
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record_minimal_symbol (name, address, ms_type, objfile)
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char *name;
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CORE_ADDR address;
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enum minimal_symbol_type ms_type;
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struct objfile *objfile;
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{
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name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
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prim_record_minimal_symbol (name, address, ms_type);
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}
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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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struct objfile *objfile)
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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 minimal symbol table.
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*/
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static void
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elf_symtab_read (abfd, addr, mainline, objfile)
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bfd *abfd;
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CORE_ADDR addr;
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int mainline;
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struct objfile *objfile;
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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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CORE_ADDR symaddr;
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enum minimal_symbol_type ms_type;
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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/weak symbols that are defined in a specific section.
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Note that bfd now puts abs symbols in their own section, so
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all symbols we are interested in will have a section. */
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if ((sym -> flags & (BSF_GLOBAL | BSF_WEAK))
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&& (sym -> section != NULL))
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{
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symaddr = sym -> value;
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/* Relocate all non-absolute symbols by base address.
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FIXME: Can we eliminate the check for mainline now,
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since shouldn't addr be 0 in this case? */
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if (!mainline && (sym -> section != &bfd_abs_section))
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{
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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 -> flags & SEC_CODE)
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{
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ms_type = mst_text;
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}
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else if (sym -> section -> flags & SEC_DATA)
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{
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ms_type = mst_data;
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}
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else
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{
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ms_type = mst_unknown;
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}
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record_minimal_symbol ((char *) sym -> name, symaddr, ms_type, objfile);
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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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/* 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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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 gdb's minimal symbol table. 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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static void
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elf_symfile_read (sf, addr, mainline)
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struct sym_fns *sf;
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CORE_ADDR addr;
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int mainline;
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{
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bfd *abfd = sf->objfile->obfd;
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struct elfinfo ei;
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struct cleanup *back_to;
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init_minimal_symbol_collection ();
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back_to = make_cleanup (discard_minimal_symbols, 0);
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/* Process the normal ELF symbol table first. */
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elf_symtab_read (abfd, addr, mainline, sf->objfile);
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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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bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &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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ei.lnoffset, ei.lnsize, sf->objfile);
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}
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if (!have_partial_symbols ())
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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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/* Install any minimal symbols that have been collected as the current
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minimal symbols for this objfile. */
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install_minimal_symbols (sf -> objfile);
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do_cleanups (back_to);
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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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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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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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_initialize_elfread ()
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{
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add_symtab_fns (&elf_sym_fns);
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}
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