coff-mips.c

基于4个mips核的noc设计

/* BFD back-end for MIPS Extended-Coff files.
   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001
   Free Software Foundation, Inc.
   Original version by Per Bothner.
   Full support added by Ian Lance Taylor, [e-mail].

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.  */

#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "coff/internal.h"
#include "coff/sym.h"
#include "coff/symconst.h"
#include "coff/ecoff.h"
#include "coff/mips.h"
#include "libcoff.h"
#include "libecoff.h"

/* Prototypes for static functions.  */

static boolean mips_ecoff_bad_format_hook PARAMS ((bfd *abfd, PTR filehdr));
static void mips_ecoff_swap_reloc_in PARAMS ((bfd *, PTR,
					      struct internal_reloc *));
static void mips_ecoff_swap_reloc_out PARAMS ((bfd *,
					       const struct internal_reloc *,
					       PTR));
static void mips_adjust_reloc_in PARAMS ((bfd *,
					  const struct internal_reloc *,
					  arelent *));
static void mips_adjust_reloc_out PARAMS ((bfd *, const arelent *,
					   struct internal_reloc *));
static bfd_reloc_status_type mips_generic_reloc PARAMS ((bfd *abfd,
							 arelent *reloc,
							 asymbol *symbol,
							 PTR data,
							 asection *section,
							 bfd *output_bfd,
							 char **error));
static bfd_reloc_status_type mips_refhi_reloc PARAMS ((bfd *abfd,
						       arelent *reloc,
						       asymbol *symbol,
						       PTR data,
						       asection *section,
						       bfd *output_bfd,
						       char **error));
static bfd_reloc_status_type mips_reflo_reloc PARAMS ((bfd *abfd,
						       arelent *reloc,
						       asymbol *symbol,
						       PTR data,
						       asection *section,
						       bfd *output_bfd,
						       char **error));
static bfd_reloc_status_type mips_gprel_reloc PARAMS ((bfd *abfd,
						       arelent *reloc,
						       asymbol *symbol,
						       PTR data,
						       asection *section,
						       bfd *output_bfd,
						       char **error));
static bfd_reloc_status_type mips_relhi_reloc PARAMS ((bfd *abfd,
						       arelent *reloc,
						       asymbol *symbol,
						       PTR data,
						       asection *section,
						       bfd *output_bfd,
						       char **error));
static bfd_reloc_status_type mips_rello_reloc PARAMS ((bfd *abfd,
						       arelent *reloc,
						       asymbol *symbol,
						       PTR data,
						       asection *section,
						       bfd *output_bfd,
						       char **error));
static bfd_reloc_status_type mips_switch_reloc PARAMS ((bfd *abfd,
							arelent *reloc,
							asymbol *symbol,
							PTR data,
							asection *section,
							bfd *output_bfd,
							char **error));
static void mips_relocate_hi PARAMS ((struct internal_reloc *refhi,
				      struct internal_reloc *reflo,
				      bfd *input_bfd,
				      asection *input_section,
				      bfd_byte *contents,
				      size_t adjust,
				      bfd_vma relocation,
				      boolean pcrel));
static boolean mips_relocate_section PARAMS ((bfd *, struct bfd_link_info *,
					      bfd *, asection *,
					      bfd_byte *, PTR));
static boolean mips_read_relocs PARAMS ((bfd *, asection *));
static boolean mips_relax_section PARAMS ((bfd *, asection *,
					   struct bfd_link_info *,
					   boolean *));
static boolean mips_relax_pcrel16 PARAMS ((struct bfd_link_info *, bfd *,
					   asection *,
					   struct ecoff_link_hash_entry *,
					   bfd_byte *, bfd_vma));
static reloc_howto_type *mips_bfd_reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));

/* ECOFF has COFF sections, but the debugging information is stored in
   a completely different format.  ECOFF targets use some of the
   swapping routines from coffswap.h, and some of the generic COFF
   routines in coffgen.c, but, unlike the real COFF targets, do not
   use coffcode.h itself.

   Get the generic COFF swapping routines, except for the reloc,
   symbol, and lineno ones.  Give them ECOFF names.  */
#define MIPSECOFF
#define NO_COFF_RELOCS
#define NO_COFF_SYMBOLS
#define NO_COFF_LINENOS
#define coff_swap_filehdr_in mips_ecoff_swap_filehdr_in
#define coff_swap_filehdr_out mips_ecoff_swap_filehdr_out
#define coff_swap_aouthdr_in mips_ecoff_swap_aouthdr_in
#define coff_swap_aouthdr_out mips_ecoff_swap_aouthdr_out
#define coff_swap_scnhdr_in mips_ecoff_swap_scnhdr_in
#define coff_swap_scnhdr_out mips_ecoff_swap_scnhdr_out
#include "coffswap.h"

/* Get the ECOFF swapping routines.  */
#define ECOFF_32
#include "ecoffswap.h"

/* How to process the various relocs types.  */

static reloc_howto_type mips_howto_table[] =
{
  /* Reloc type 0 is ignored.  The reloc reading code ensures that
     this is a reference to the .abs section, which will cause
     bfd_perform_relocation to do nothing.  */
  HOWTO (MIPS_R_IGNORE,	/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 0,			/* special_function */
	 "IGNORE",		/* name */
	 false,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 16 bit reference to a symbol, normally from a data section.  */
  HOWTO (MIPS_R_REFHALF,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mips_generic_reloc,	/* special_function */
	 "REFHALF",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 32 bit reference to a symbol, normally from a data section.  */
  HOWTO (MIPS_R_REFWORD,	/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mips_generic_reloc,	/* special_function */
	 "REFWORD",		/* name */
	 true,			/* partial_inplace */
	 0xffffffff,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A 26 bit absolute jump address.  */
  HOWTO (MIPS_R_JMPADDR,	/* type */
	 2,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 26,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 			/* This needs complex overflow
				   detection, because the upper four
				   bits must match the PC.  */
	 mips_generic_reloc,	/* special_function */
	 "JMPADDR",		/* name */
	 true,			/* partial_inplace */
	 0x3ffffff,		/* src_mask */
	 0x3ffffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* The high 16 bits of a symbol value.  Handled by the function
     mips_refhi_reloc.  */
  HOWTO (MIPS_R_REFHI,		/* type */
	 16,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mips_refhi_reloc,	/* special_function */
	 "REFHI",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* The low 16 bits of a symbol value.  */
  HOWTO (MIPS_R_REFLO,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 mips_reflo_reloc,	/* special_function */
	 "REFLO",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A reference to an offset from the gp register.  Handled by the
     function mips_gprel_reloc.  */
  HOWTO (MIPS_R_GPREL,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 mips_gprel_reloc,	/* special_function */
	 "GPREL",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* A reference to a literal using an offset from the gp register.
     Handled by the function mips_gprel_reloc.  */
  HOWTO (MIPS_R_LITERAL,	/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 mips_gprel_reloc,	/* special_function */
	 "LITERAL",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */

  EMPTY_HOWTO (8),
  EMPTY_HOWTO (9),
  EMPTY_HOWTO (10),
  EMPTY_HOWTO (11),

  /* This reloc is a Cygnus extension used when generating position
     independent code for embedded systems.  It represents a 16 bit PC
     relative reloc rightshifted twice as used in the MIPS branch
     instructions.  */
  HOWTO (MIPS_R_PCREL16,	/* type */
	 2,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_signed, /* complain_on_overflow */
	 mips_generic_reloc,	/* special_function */
	 "PCREL16",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 true),			/* pcrel_offset */

  /* This reloc is a Cygnus extension used when generating position
     independent code for embedded systems.  It represents the high 16
     bits of a PC relative reloc.  The next reloc must be
     MIPS_R_RELLO, and the addend is formed from the addends of the
     two instructions, just as in MIPS_R_REFHI and MIPS_R_REFLO.  The
     final value is actually PC relative to the location of the
     MIPS_R_RELLO reloc, not the MIPS_R_RELHI reloc.  */
  HOWTO (MIPS_R_RELHI,		/* type */
	 16,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow */
	 mips_relhi_reloc,	/* special_function */
	 "RELHI",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 true),			/* pcrel_offset */

  /* This reloc is a Cygnus extension used when generating position
     independent code for embedded systems.  It represents the low 16
     bits of a PC relative reloc.  */
  HOWTO (MIPS_R_RELLO,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 mips_rello_reloc,	/* special_function */
	 "RELLO",		/* name */
	 true,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 true),			/* pcrel_offset */

  EMPTY_HOWTO (15),
  EMPTY_HOWTO (16),
  EMPTY_HOWTO (17),
  EMPTY_HOWTO (18),
  EMPTY_HOWTO (19),
  EMPTY_HOWTO (20),
  EMPTY_HOWTO (21),

  /* This reloc is a Cygnus extension used when generating position
     independent code for embedded systems.  It represents an entry in
     a switch table, which is the difference between two symbols in
     the .text section.  The symndx is actually the offset from the
     reloc address to the subtrahend.  See include/coff/mips.h for
     more details.  */
  HOWTO (MIPS_R_SWITCH,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 true,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 mips_switch_reloc,	/* special_function */
	 "SWITCH",		/* name */
	 true,			/* partial_inplace */
	 0xffffffff,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 true)			/* pcrel_offset */
};

#define MIPS_HOWTO_COUNT \
  (sizeof mips_howto_table / sizeof mips_howto_table[0])

/* When the linker is doing relaxing, it may change a external PCREL16
   reloc.  This typically represents an instruction like
       bal foo
   We change it to
       .set  noreorder
       bal   $L1
       lui   $at,%hi(foo - $L1)
     $L1:
       addiu $at,%lo(foo - $L1)
       addu  $at,$at,$31
       jalr  $at
   PCREL16_EXPANSION_ADJUSTMENT is the number of bytes this changes the
   instruction by.  */

#define PCREL16_EXPANSION_ADJUSTMENT (4 * 4)

/* See whether the magic number matches.  */

static boolean
mips_ecoff_bad_format_hook (abfd, filehdr)
     bfd *abfd;
     PTR filehdr;
{
  struct internal_filehdr *internal_f = (struct internal_filehdr *) filehdr;

  switch (internal_f->f_magic)
    {
    case MIPS_MAGIC_1:
      /* I don't know what endianness this implies.  */
      return true;

    case MIPS_MAGIC_BIG:
    case MIPS_MAGIC_BIG2:
    case MIPS_MAGIC_BIG3:
      return bfd_big_endian (abfd);

    case MIPS_MAGIC_LITTLE:
    case MIPS_MAGIC_LITTLE2:
    case MIPS_MAGIC_LITTLE3:
      return bfd_little_endian (abfd);

    default:
      return false;
    }
}

/* Reloc handling.  MIPS ECOFF relocs are packed into 8 bytes in
   external form.  They use a bit which indicates whether the symbol
   is external.  */

/* Swap a reloc in.  */

static void
mips_ecoff_swap_reloc_in (abfd, ext_ptr, intern)
     bfd *abfd;