elf.c

基于4个mips核的noc设计

/* ELF executable support for BFD.
   Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
   Free Software Foundation, Inc.

This file is part of BFD, the Binary File Descriptor library.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/*

SECTION
	ELF backends

	BFD support for ELF formats is being worked on.
	Currently, the best supported back ends are for sparc and i386
	(running svr4 or Solaris 2).

	Documentation of the internals of the support code still needs
	to be written.  The code is changing quickly enough that we
	haven't bothered yet.
 */

/* For sparc64-cross-sparc32.  */
#define _SYSCALL32
#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"
#include "libbfd.h"
#define ARCH_SIZE 0
#include "elf-bfd.h"

static INLINE struct elf_segment_map *make_mapping
  PARAMS ((bfd *, asection **, unsigned int, unsigned int, boolean));
static boolean map_sections_to_segments PARAMS ((bfd *));
static int elf_sort_sections PARAMS ((const PTR, const PTR));
static boolean assign_file_positions_for_segments PARAMS ((bfd *));
static boolean assign_file_positions_except_relocs PARAMS ((bfd *));
static boolean prep_headers PARAMS ((bfd *));
static boolean swap_out_syms PARAMS ((bfd *, struct bfd_strtab_hash **, int));
static boolean copy_private_bfd_data PARAMS ((bfd *, bfd *));
static char *elf_read PARAMS ((bfd *, long, unsigned int));
static void elf_fake_sections PARAMS ((bfd *, asection *, PTR));
static boolean assign_section_numbers PARAMS ((bfd *));
static INLINE int sym_is_global PARAMS ((bfd *, asymbol *));
static boolean elf_map_symbols PARAMS ((bfd *));
static bfd_size_type get_program_header_size PARAMS ((bfd *));
static boolean elfcore_read_notes PARAMS ((bfd *, bfd_vma, bfd_vma));
static boolean elf_find_function PARAMS ((bfd *, asection *,
                                         asymbol **,
                                         bfd_vma, const char **,
                                         const char **));

/* Swap version information in and out.  The version information is
   currently size independent.  If that ever changes, this code will
   need to move into elfcode.h.  */

/* Swap in a Verdef structure.  */

void
_bfd_elf_swap_verdef_in (abfd, src, dst)
     bfd *abfd;
     const Elf_External_Verdef *src;
     Elf_Internal_Verdef *dst;
{
  dst->vd_version = bfd_h_get_16 (abfd, src->vd_version);
  dst->vd_flags   = bfd_h_get_16 (abfd, src->vd_flags);
  dst->vd_ndx     = bfd_h_get_16 (abfd, src->vd_ndx);
  dst->vd_cnt     = bfd_h_get_16 (abfd, src->vd_cnt);
  dst->vd_hash    = bfd_h_get_32 (abfd, src->vd_hash);
  dst->vd_aux     = bfd_h_get_32 (abfd, src->vd_aux);
  dst->vd_next    = bfd_h_get_32 (abfd, src->vd_next);
}

/* Swap out a Verdef structure.  */

void
_bfd_elf_swap_verdef_out (abfd, src, dst)
     bfd *abfd;
     const Elf_Internal_Verdef *src;
     Elf_External_Verdef *dst;
{
  bfd_h_put_16 (abfd, src->vd_version, dst->vd_version);
  bfd_h_put_16 (abfd, src->vd_flags, dst->vd_flags);
  bfd_h_put_16 (abfd, src->vd_ndx, dst->vd_ndx);
  bfd_h_put_16 (abfd, src->vd_cnt, dst->vd_cnt);
  bfd_h_put_32 (abfd, src->vd_hash, dst->vd_hash);
  bfd_h_put_32 (abfd, src->vd_aux, dst->vd_aux);
  bfd_h_put_32 (abfd, src->vd_next, dst->vd_next);
}

/* Swap in a Verdaux structure.  */

void
_bfd_elf_swap_verdaux_in (abfd, src, dst)
     bfd *abfd;
     const Elf_External_Verdaux *src;
     Elf_Internal_Verdaux *dst;
{
  dst->vda_name = bfd_h_get_32 (abfd, src->vda_name);
  dst->vda_next = bfd_h_get_32 (abfd, src->vda_next);
}

/* Swap out a Verdaux structure.  */

void
_bfd_elf_swap_verdaux_out (abfd, src, dst)
     bfd *abfd;
     const Elf_Internal_Verdaux *src;
     Elf_External_Verdaux *dst;
{
  bfd_h_put_32 (abfd, src->vda_name, dst->vda_name);
  bfd_h_put_32 (abfd, src->vda_next, dst->vda_next);
}

/* Swap in a Verneed structure.  */

void
_bfd_elf_swap_verneed_in (abfd, src, dst)
     bfd *abfd;
     const Elf_External_Verneed *src;
     Elf_Internal_Verneed *dst;
{
  dst->vn_version = bfd_h_get_16 (abfd, src->vn_version);
  dst->vn_cnt     = bfd_h_get_16 (abfd, src->vn_cnt);
  dst->vn_file    = bfd_h_get_32 (abfd, src->vn_file);
  dst->vn_aux     = bfd_h_get_32 (abfd, src->vn_aux);
  dst->vn_next    = bfd_h_get_32 (abfd, src->vn_next);
}

/* Swap out a Verneed structure.  */

void
_bfd_elf_swap_verneed_out (abfd, src, dst)
     bfd *abfd;
     const Elf_Internal_Verneed *src;
     Elf_External_Verneed *dst;
{
  bfd_h_put_16 (abfd, src->vn_version, dst->vn_version);
  bfd_h_put_16 (abfd, src->vn_cnt, dst->vn_cnt);
  bfd_h_put_32 (abfd, src->vn_file, dst->vn_file);
  bfd_h_put_32 (abfd, src->vn_aux, dst->vn_aux);
  bfd_h_put_32 (abfd, src->vn_next, dst->vn_next);
}

/* Swap in a Vernaux structure.  */

void
_bfd_elf_swap_vernaux_in (abfd, src, dst)
     bfd *abfd;
     const Elf_External_Vernaux *src;
     Elf_Internal_Vernaux *dst;
{
  dst->vna_hash  = bfd_h_get_32 (abfd, src->vna_hash);
  dst->vna_flags = bfd_h_get_16 (abfd, src->vna_flags);
  dst->vna_other = bfd_h_get_16 (abfd, src->vna_other);
  dst->vna_name  = bfd_h_get_32 (abfd, src->vna_name);
  dst->vna_next  = bfd_h_get_32 (abfd, src->vna_next);
}

/* Swap out a Vernaux structure.  */

void
_bfd_elf_swap_vernaux_out (abfd, src, dst)
     bfd *abfd;
     const Elf_Internal_Vernaux *src;
     Elf_External_Vernaux *dst;
{
  bfd_h_put_32 (abfd, src->vna_hash, dst->vna_hash);
  bfd_h_put_16 (abfd, src->vna_flags, dst->vna_flags);
  bfd_h_put_16 (abfd, src->vna_other, dst->vna_other);
  bfd_h_put_32 (abfd, src->vna_name, dst->vna_name);
  bfd_h_put_32 (abfd, src->vna_next, dst->vna_next);
}

/* Swap in a Versym structure.  */

void
_bfd_elf_swap_versym_in (abfd, src, dst)
     bfd *abfd;
     const Elf_External_Versym *src;
     Elf_Internal_Versym *dst;
{
  dst->vs_vers = bfd_h_get_16 (abfd, src->vs_vers);
}

/* Swap out a Versym structure.  */

void
_bfd_elf_swap_versym_out (abfd, src, dst)
     bfd *abfd;
     const Elf_Internal_Versym *src;
     Elf_External_Versym *dst;
{
  bfd_h_put_16 (abfd, src->vs_vers, dst->vs_vers);
}

/* Standard ELF hash function.  Do not change this function; you will
   cause invalid hash tables to be generated.  */

unsigned long
bfd_elf_hash (namearg)
     const char *namearg;
{
  const unsigned char *name = (const unsigned char *) namearg;
  unsigned long h = 0;
  unsigned long g;
  int ch;

  while ((ch = *name++) != '\0')
    {
      h = (h << 4) + ch;
      if ((g = (h & 0xf0000000)) != 0)
	{
	  h ^= g >> 24;
	  /* The ELF ABI says `h &= ~g', but this is equivalent in
	     this case and on some machines one insn instead of two.  */
	  h ^= g;
	}
    }
  return h;
}

/* Read a specified number of bytes at a specified offset in an ELF
   file, into a newly allocated buffer, and return a pointer to the
   buffer.  */

static char *
elf_read (abfd, offset, size)
     bfd *abfd;
     long offset;
     unsigned int size;
{
  char *buf;

  if ((buf = bfd_alloc (abfd, size)) == NULL)
    return NULL;
  if (bfd_seek (abfd, offset, SEEK_SET) == -1)
    return NULL;
  if (bfd_read ((PTR) buf, size, 1, abfd) != size)
    {
      if (bfd_get_error () != bfd_error_system_call)
	bfd_set_error (bfd_error_file_truncated);
      return NULL;
    }
  return buf;
}

boolean
bfd_elf_mkobject (abfd)
     bfd *abfd;
{
  /* This just does initialization.  */
  /* coff_mkobject zalloc's space for tdata.coff_obj_data ...  */
  elf_tdata (abfd) = (struct elf_obj_tdata *)
    bfd_zalloc (abfd, sizeof (struct elf_obj_tdata));
  if (elf_tdata (abfd) == 0)
    return false;
  /* Since everything is done at close time, do we need any
     initialization?  */

  return true;
}

boolean
bfd_elf_mkcorefile (abfd)
     bfd *abfd;
{
  /* I think this can be done just like an object file.  */
  return bfd_elf_mkobject (abfd);
}

char *
bfd_elf_get_str_section (abfd, shindex)
     bfd *abfd;
     unsigned int shindex;
{
  Elf_Internal_Shdr **i_shdrp;
  char *shstrtab = NULL;
  unsigned int offset;
  unsigned int shstrtabsize;

  i_shdrp = elf_elfsections (abfd);
  if (i_shdrp == 0 || i_shdrp[shindex] == 0)
    return 0;

  shstrtab = (char *) i_shdrp[shindex]->contents;
  if (shstrtab == NULL)
    {
      /* No cached one, attempt to read, and cache what we read.  */
      offset = i_shdrp[shindex]->sh_offset;
      shstrtabsize = i_shdrp[shindex]->sh_size;
      shstrtab = elf_read (abfd, offset, shstrtabsize);
      i_shdrp[shindex]->contents = (PTR) shstrtab;
    }
  return shstrtab;
}

char *
bfd_elf_string_from_elf_section (abfd, shindex, strindex)
     bfd *abfd;
     unsigned int shindex;
     unsigned int strindex;
{
  Elf_Internal_Shdr *hdr;

  if (strindex == 0)
    return "";

  hdr = elf_elfsections (abfd)[shindex];

  if (hdr->contents == NULL
      && bfd_elf_get_str_section (abfd, shindex) == NULL)
    return NULL;

  if (strindex >= hdr->sh_size)
    {
      (*_bfd_error_handler)
	(_("%s: invalid string offset %u >= %lu for section `%s'"),
	 bfd_get_filename (abfd), strindex, (unsigned long) hdr->sh_size,
	 ((shindex == elf_elfheader(abfd)->e_shstrndx
	   && strindex == hdr->sh_name)
	  ? ".shstrtab"
	  : elf_string_from_elf_strtab (abfd, hdr->sh_name)));
      return "";
    }

  return ((char *) hdr->contents) + strindex;
}

/* Make a BFD section from an ELF section.  We store a pointer to the
   BFD section in the bfd_section field of the header.  */

boolean
_bfd_elf_make_section_from_shdr (abfd, hdr, name)
     bfd *abfd;
     Elf_Internal_Shdr *hdr;
     const char *name;
{
  asection *newsect;
  flagword flags;
  struct elf_backend_data *bed;

  if (hdr->bfd_section != NULL)
    {
      BFD_ASSERT (strcmp (name,
			  bfd_get_section_name (abfd, hdr->bfd_section)) == 0);
      return true;
    }

  newsect = bfd_make_section_anyway (abfd, name);
  if (newsect == NULL)
    return false;

  newsect->filepos = hdr->sh_offset;

  if (! bfd_set_section_vma (abfd, newsect, hdr->sh_addr)
      || ! bfd_set_section_size (abfd, newsect, hdr->sh_size)
      || ! bfd_set_section_alignment (abfd, newsect,
				      bfd_log2 (hdr->sh_addralign)))
    return false;

  flags = SEC_NO_FLAGS;
  if (hdr->sh_type != SHT_NOBITS)
    flags |= SEC_HAS_CONTENTS;
  if ((hdr->sh_flags & SHF_ALLOC) != 0)
    {
      flags |= SEC_ALLOC;
      if (hdr->sh_type != SHT_NOBITS)
	flags |= SEC_LOAD;
    }
  if ((hdr->sh_flags & SHF_WRITE) == 0)
    flags |= SEC_READONLY;
  if ((hdr->sh_flags & SHF_EXECINSTR) != 0)
    flags |= SEC_CODE;
  else if ((flags & SEC_LOAD) != 0)
    flags |= SEC_DATA;

  /* The debugging sections appear to be recognized only by name, not
     any sort of flag.  */
  {
    static const char *debug_sec_names [] =
    {
      ".debug",
      ".gnu.linkonce.wi.",
      ".line",
      ".stab"
    };
    int i;

    for (i = sizeof (debug_sec_names) / sizeof (debug_sec_names[0]); i--;)
      if (strncmp (name, debug_sec_names[i], strlen (debug_sec_names[i])) == 0)
	break;

    if (i >= 0)
      flags |= SEC_DEBUGGING;
  }

  /* As a GNU extension, if the name begins with .gnu.linkonce, we
     only link a single copy of the section.  This is used to support
     g++.  g++ will emit each template expansion in its own section.
     The symbols will be defined as weak, so that multiple definitions
     are permitted.  The GNU linker extension is to actually discard
     all but one of the sections.  */
  if (strncmp (name, ".gnu.linkonce", sizeof ".gnu.linkonce" - 1) == 0)
    flags |= SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD;

  bed = get_elf_backend_data (abfd);
  if (bed->elf_backend_section_flags)
    if (! bed->elf_backend_section_flags (&flags, hdr))
      return false;

  if (! bfd_set_section_flags (abfd, newsect, flags))
    return false;

  if ((flags & SEC_ALLOC) != 0)
    {
      Elf_Internal_Phdr *phdr;
      unsigned int i;

      /* Look through the phdrs to see if we need to adjust the lma.
         If all the p_paddr fields are zero, we ignore them, since
         some ELF linkers produce such output.  */
      phdr = elf_tdata (abfd)->phdr;
      for (i = 0; i < elf_elfheader (abfd)->e_phnum; i++, phdr++)
	{
	  if (phdr->p_paddr != 0)
	    break;
	}
      if (i < elf_elfheader (abfd)->e_phnum)
	{
	  phdr = elf_tdata (abfd)->phdr;
	  for (i = 0; i < elf_elfheader (abfd)->e_phnum; i++, phdr++)
	    {
	      if (phdr->p_type == PT_LOAD
		  && phdr->p_vaddr != phdr->p_paddr
		  && phdr->p_vaddr <= hdr->sh_addr
		  && (phdr->p_vaddr + phdr->p_memsz
		      >= hdr->sh_addr + hdr->sh_size)
		  && ((flags & SEC_LOAD) == 0
		      || (phdr->p_offset <= (bfd_vma) hdr->sh_offset
			  && (phdr->p_offset + phdr->p_filesz
			      >= hdr->sh_offset + hdr->sh_size))))