elf32-mips.c

基于4个mips核的noc设计

/* MIPS-specific support for 32-bit ELF
   Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
   Free Software Foundation, Inc.

   Most of the information added by Ian Lance Taylor, Cygnus Support,
   <[e-mail]>.
   N32/64 ABI support added by Mark Mitchell, CodeSourcery, LLC.
   <[e-mail]>
   Traditional MIPS targets support added by Koundinya.K, Dansk Data
   Elektronik & Operations Research Group. <[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.  */

/* This file handles MIPS ELF targets.  SGI Irix 5 uses a slightly
   different MIPS ELF from other targets.  This matters when linking.
   This file supports both, switching at runtime.  */

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "bfdlink.h"
#include "genlink.h"
#include "elf-bfd.h"
#include "elf/mips.h"

/* Get the ECOFF swapping routines.  */
#include "coff/sym.h"
#include "coff/symconst.h"
#include "coff/internal.h"
#include "coff/ecoff.h"
#include "coff/mips.h"
#define ECOFF_SIGNED_32
#include "ecoffswap.h"

/* This structure is used to hold .got information when linking.  It
   is stored in the tdata field of the bfd_elf_section_data structure.  */

struct mips_got_info
{
  /* The global symbol in the GOT with the lowest index in the dynamic
     symbol table.  */
  struct elf_link_hash_entry *global_gotsym;
  /* The number of global .got entries.  */
  unsigned int global_gotno;
  /* The number of local .got entries.  */
  unsigned int local_gotno;
  /* The number of local .got entries we have used.  */
  unsigned int assigned_gotno;
};

/* The MIPS ELF linker needs additional information for each symbol in
   the global hash table.  */

struct mips_elf_link_hash_entry
{
  struct elf_link_hash_entry root;

  /* External symbol information.  */
  EXTR esym;

  /* Number of R_MIPS_32, R_MIPS_REL32, or R_MIPS_64 relocs against
     this symbol.  */
  unsigned int possibly_dynamic_relocs;

  /* The index of the first dynamic relocation (in the .rel.dyn
     section) against this symbol.  */
  unsigned int min_dyn_reloc_index;

  /* We must not create a stub for a symbol that has relocations
     related to taking the function's address, i.e. any but
     R_MIPS_CALL*16 ones -- see "MIPS ABI Supplement, 3rd Edition",
     p. 4-20.  */
  boolean no_fn_stub;

  /* If there is a stub that 32 bit functions should use to call this
     16 bit function, this points to the section containing the stub.  */
  asection *fn_stub;

  /* Whether we need the fn_stub; this is set if this symbol appears
     in any relocs other than a 16 bit call.  */
  boolean need_fn_stub;

  /* If there is a stub that 16 bit functions should use to call this
     32 bit function, this points to the section containing the stub.  */
  asection *call_stub;

  /* This is like the call_stub field, but it is used if the function
     being called returns a floating point value.  */
  asection *call_fp_stub;
};

static bfd_reloc_status_type mips32_64bit_reloc
  PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
static reloc_howto_type *bfd_elf32_bfd_reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));
static reloc_howto_type *mips_rtype_to_howto
  PARAMS ((unsigned int));
static void mips_info_to_howto_rel
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rel *));
static void mips_info_to_howto_rela
  PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));
static void bfd_mips_elf32_swap_gptab_in
  PARAMS ((bfd *, const Elf32_External_gptab *, Elf32_gptab *));
static void bfd_mips_elf32_swap_gptab_out
  PARAMS ((bfd *, const Elf32_gptab *, Elf32_External_gptab *));
#if 0
static void bfd_mips_elf_swap_msym_in
  PARAMS ((bfd *, const Elf32_External_Msym *, Elf32_Internal_Msym *));
#endif
static void bfd_mips_elf_swap_msym_out
  PARAMS ((bfd *, const Elf32_Internal_Msym *, Elf32_External_Msym *));
static boolean mips_elf_sym_is_global PARAMS ((bfd *, asymbol *));
static boolean mips_elf_create_procedure_table
  PARAMS ((PTR, bfd *, struct bfd_link_info *, asection *,
	   struct ecoff_debug_info *));
static INLINE int elf_mips_isa PARAMS ((flagword));
static INLINE int elf_mips_mach PARAMS ((flagword));
static INLINE char* elf_mips_abi_name PARAMS ((bfd *));
static boolean mips_elf_is_local_label_name
  PARAMS ((bfd *, const char *));
static struct bfd_hash_entry *mips_elf_link_hash_newfunc
  PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
static int gptab_compare PARAMS ((const void *, const void *));
static bfd_reloc_status_type mips16_jump_reloc
  PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
static bfd_reloc_status_type mips16_gprel_reloc
  PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
static boolean mips_elf_create_compact_rel_section
  PARAMS ((bfd *, struct bfd_link_info *));
static boolean mips_elf_create_got_section
  PARAMS ((bfd *, struct bfd_link_info *));
static bfd_reloc_status_type mips_elf_final_gp
  PARAMS ((bfd *, asymbol *, boolean, char **, bfd_vma *));
static bfd_byte *elf32_mips_get_relocated_section_contents
  PARAMS ((bfd *, struct bfd_link_info *, struct bfd_link_order *,
	   bfd_byte *, boolean, asymbol **));
static asection *mips_elf_create_msym_section
  PARAMS ((bfd *));
static void mips_elf_irix6_finish_dynamic_symbol
  PARAMS ((bfd *, const char *, Elf_Internal_Sym *));
static bfd_vma mips_elf_sign_extend PARAMS ((bfd_vma, int));
static boolean mips_elf_overflow_p PARAMS ((bfd_vma, int));
static bfd_vma mips_elf_high PARAMS ((bfd_vma));
static bfd_vma mips_elf_higher PARAMS ((bfd_vma));
static bfd_vma mips_elf_highest PARAMS ((bfd_vma));
static bfd_vma mips_elf_global_got_index
  PARAMS ((bfd *, struct elf_link_hash_entry *));
static bfd_vma mips_elf_local_got_index
  PARAMS ((bfd *, struct bfd_link_info *, bfd_vma));
static bfd_vma mips_elf_got_offset_from_index
  PARAMS ((bfd *, bfd *, bfd_vma));
static boolean mips_elf_record_global_got_symbol
  PARAMS ((struct elf_link_hash_entry *, struct bfd_link_info *,
	   struct mips_got_info *));
static bfd_vma mips_elf_got_page
  PARAMS ((bfd *, struct bfd_link_info *, bfd_vma, bfd_vma *));
static const Elf_Internal_Rela *mips_elf_next_relocation
  PARAMS ((unsigned int, const Elf_Internal_Rela *,
	   const Elf_Internal_Rela *));
static bfd_reloc_status_type mips_elf_calculate_relocation
  PARAMS ((bfd *, bfd *, asection *, struct bfd_link_info *,
	   const Elf_Internal_Rela *, bfd_vma, reloc_howto_type *,
	   Elf_Internal_Sym *, asection **, bfd_vma *, const char **,
	   boolean *));
static bfd_vma mips_elf_obtain_contents
  PARAMS ((reloc_howto_type *, const Elf_Internal_Rela *, bfd *, bfd_byte *));
static boolean mips_elf_perform_relocation
  PARAMS ((struct bfd_link_info *, reloc_howto_type *,
	   const Elf_Internal_Rela *, bfd_vma,
	   bfd *, asection *, bfd_byte *, boolean));
static boolean mips_elf_assign_gp PARAMS ((bfd *, bfd_vma *));
static boolean mips_elf_sort_hash_table_f
  PARAMS ((struct mips_elf_link_hash_entry *, PTR));
static boolean mips_elf_sort_hash_table
  PARAMS ((struct bfd_link_info *, unsigned long));
static asection * mips_elf_got_section PARAMS ((bfd *));
static struct mips_got_info *mips_elf_got_info
  PARAMS ((bfd *, asection **));
static boolean mips_elf_local_relocation_p
  PARAMS ((bfd *, const Elf_Internal_Rela *, asection **, boolean));
static bfd_vma mips_elf_create_local_got_entry
  PARAMS ((bfd *, struct mips_got_info *, asection *, bfd_vma));
static bfd_vma mips_elf_got16_entry
  PARAMS ((bfd *, struct bfd_link_info *, bfd_vma, boolean));
static boolean mips_elf_create_dynamic_relocation
  PARAMS ((bfd *, struct bfd_link_info *, const Elf_Internal_Rela *,
	   struct mips_elf_link_hash_entry *, asection *,
	   bfd_vma, bfd_vma *, asection *));
static void mips_elf_allocate_dynamic_relocations
  PARAMS ((bfd *, unsigned int));
static boolean mips_elf_stub_section_p
  PARAMS ((bfd *, asection *));
static int sort_dynamic_relocs
  PARAMS ((const void *, const void *));

extern const bfd_target bfd_elf32_tradbigmips_vec;
extern const bfd_target bfd_elf32_tradlittlemips_vec;
#ifdef BFD64
extern const bfd_target bfd_elf64_tradbigmips_vec;
extern const bfd_target bfd_elf64_tradlittlemips_vec;
#endif

/* The level of IRIX compatibility we're striving for.  */

typedef enum {
  ict_none,
  ict_irix5,
  ict_irix6
} irix_compat_t;

/* This will be used when we sort the dynamic relocation records.  */
static bfd *reldyn_sorting_bfd;

/* Nonzero if ABFD is using the N32 ABI.  */

#define ABI_N32_P(abfd) \
  ((elf_elfheader (abfd)->e_flags & EF_MIPS_ABI2) != 0)

/* Nonzero if ABFD is using the 64-bit ABI. */
#define ABI_64_P(abfd) \
  ((elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64) != 0)

/* Depending on the target vector we generate some version of Irix
   executables or "normal" MIPS ELF ABI executables.  */
#ifdef BFD64
#define IRIX_COMPAT(abfd) \
  (((abfd->xvec == &bfd_elf64_tradbigmips_vec) || \
    (abfd->xvec == &bfd_elf64_tradlittlemips_vec) || \
    (abfd->xvec == &bfd_elf32_tradbigmips_vec) || \
    (abfd->xvec == &bfd_elf32_tradlittlemips_vec)) ? ict_none : \
  ((ABI_N32_P (abfd) || ABI_64_P (abfd)) ? ict_irix6 : ict_irix5))
#else
#define IRIX_COMPAT(abfd) \
  (((abfd->xvec == &bfd_elf32_tradbigmips_vec) || \
    (abfd->xvec == &bfd_elf32_tradlittlemips_vec)) ? ict_none : \
  ((ABI_N32_P (abfd) || ABI_64_P (abfd)) ? ict_irix6 : ict_irix5))
#endif

/* Whether we are trying to be compatible with IRIX at all.  */
#define SGI_COMPAT(abfd) \
  (IRIX_COMPAT (abfd) != ict_none)

/* The name of the msym section.  */
#define MIPS_ELF_MSYM_SECTION_NAME(abfd) ".msym"

/* The name of the srdata section.  */
#define MIPS_ELF_SRDATA_SECTION_NAME(abfd) ".srdata"

/* The name of the options section.  */
#define MIPS_ELF_OPTIONS_SECTION_NAME(abfd) \
  (IRIX_COMPAT (abfd) == ict_irix6 ? ".MIPS.options" : ".options")

/* The name of the stub section.  */
#define MIPS_ELF_STUB_SECTION_NAME(abfd) \
  (IRIX_COMPAT (abfd) == ict_irix6 ? ".MIPS.stubs" : ".stub")

/* The name of the dynamic relocation section.  */
#define MIPS_ELF_REL_DYN_SECTION_NAME(abfd) ".rel.dyn"

/* The size of an external REL relocation.  */
#define MIPS_ELF_REL_SIZE(abfd) \
  (get_elf_backend_data (abfd)->s->sizeof_rel)

/* The size of an external dynamic table entry.  */
#define MIPS_ELF_DYN_SIZE(abfd) \
  (get_elf_backend_data (abfd)->s->sizeof_dyn)

/* The size of a GOT entry.  */
#define MIPS_ELF_GOT_SIZE(abfd) \
  (get_elf_backend_data (abfd)->s->arch_size / 8)

/* The size of a symbol-table entry.  */
#define MIPS_ELF_SYM_SIZE(abfd) \
  (get_elf_backend_data (abfd)->s->sizeof_sym)

/* The default alignment for sections, as a power of two.  */
#define MIPS_ELF_LOG_FILE_ALIGN(abfd)				\
  (get_elf_backend_data (abfd)->s->file_align == 8 ? 3 : 2)

/* Get word-sized data.  */
#define MIPS_ELF_GET_WORD(abfd, ptr) \
  (ABI_64_P (abfd) ? bfd_get_64 (abfd, ptr) : bfd_get_32 (abfd, ptr))

/* Put out word-sized data.  */
#define MIPS_ELF_PUT_WORD(abfd, val, ptr)	\
  (ABI_64_P (abfd) 				\
   ? bfd_put_64 (abfd, val, ptr) 		\
   : bfd_put_32 (abfd, val, ptr))

/* Add a dynamic symbol table-entry.  */
#ifdef BFD64
#define MIPS_ELF_ADD_DYNAMIC_ENTRY(info, tag, val) \
  (ABI_64_P (elf_hash_table (info)->dynobj)	   \
   ? bfd_elf64_add_dynamic_entry (info, tag, val)  \
   : bfd_elf32_add_dynamic_entry (info, tag, val))
#else
#define MIPS_ELF_ADD_DYNAMIC_ENTRY(info, tag, val) \
  (ABI_64_P (elf_hash_table (info)->dynobj)	   \
   ? (abort (), false)                             \
   : bfd_elf32_add_dynamic_entry (info, tag, val))
#endif

/* The number of local .got entries we reserve.  */
#define MIPS_RESERVED_GOTNO (2)

/* Instructions which appear in a stub.  For some reason the stub is
   slightly different on an SGI system.  */
#define ELF_MIPS_GP_OFFSET(abfd) (SGI_COMPAT (abfd) ? 0x7ff0 : 0x8000)
#define STUB_LW(abfd)						\
  (SGI_COMPAT (abfd)						\
   ? (ABI_64_P (abfd)  						\
      ? 0xdf998010		/* ld t9,0x8010(gp) */		\
      : 0x8f998010)             /* lw t9,0x8010(gp) */		\
   : 0x8f998010)		/* lw t9,0x8000(gp) */
#define STUB_MOVE(abfd)                                         \
  (SGI_COMPAT (abfd) ? 0x03e07825 : 0x03e07821)         /* move t7,ra */
#define STUB_JALR 0x0320f809				/* jal t9 */
#define STUB_LI16(abfd)                                         \
  (SGI_COMPAT (abfd) ? 0x34180000 : 0x24180000)         /* ori t8,zero,0 */
#define MIPS_FUNCTION_STUB_SIZE (16)

#if 0
/* We no longer try to identify particular sections for the .dynsym
   section.  When we do, we wind up crashing if there are other random
   sections with relocations.  */

/* Names of sections which appear in the .dynsym section in an Irix 5
   executable.  */

static const char * const mips_elf_dynsym_sec_names[] =
{
  ".text",
  ".init",
  ".fini",
  ".data",
  ".rodata",
  ".sdata",
  ".sbss",
  ".bss",
  NULL
};

#define SIZEOF_MIPS_DYNSYM_SECNAMES \
  (sizeof mips_elf_dynsym_sec_names / sizeof mips_elf_dynsym_sec_names[0])

/* The number of entries in mips_elf_dynsym_sec_names which go in the
   text segment.  */

#define MIPS_TEXT_DYNSYM_SECNO (3)

#endif /* 0 */

/* The names of the runtime procedure table symbols used on Irix 5.  */

static const char * const mips_elf_dynsym_rtproc_names[] =
{
  "_procedure_table",
  "_procedure_string_table",
  "_procedure_table_size",
  NULL
};

/* These structures are used to generate the .compact_rel section on
   Irix 5.  */

typedef struct
{
  unsigned long id1;		/* Always one?  */
  unsigned long num;		/* Number of compact relocation entries.  */
  unsigned long id2;		/* Always two?  */
  unsigned long offset;		/* The file offset of the first relocation.  */
  unsigned long reserved0;	/* Zero?  */
  unsigned long reserved1;	/* Zero?  */
} Elf32_compact_rel;

typedef struct
{
  bfd_byte id1[4];
  bfd_byte num[4];
  bfd_byte id2[4];
  bfd_byte offset[4];
  bfd_byte reserved0[4];
  bfd_byte reserved1[4];
} Elf32_External_compact_rel;

typedef struct
{
  unsigned int ctype : 1;	/* 1: long 0: short format. See below.  */
  unsigned int rtype : 4;	/* Relocation types. See below.  */
  unsigned int dist2to : 8;
  unsigned int relvaddr : 19;	/* (VADDR - vaddr of the previous entry)/ 4 */
  unsigned long konst;		/* KONST field. See below.  */
  unsigned long vaddr;		/* VADDR to be relocated.  */
} Elf32_crinfo;

typedef struct
{
  unsigned int ctype : 1;	/* 1: long 0: short format. See below.  */
  unsigned int rtype : 4;	/* Relocation types. See below.  */
  unsigned int dist2to : 8;
  unsigned int relvaddr : 19;	/* (VADDR - vaddr of the previous entry)/ 4 */
  unsigned long konst;		/* KONST field. See below.  */
} Elf32_crinfo2;

typedef struct
{
  bfd_byte info[4];
  bfd_byte konst[4];
  bfd_byte vaddr[4];
} Elf32_External_crinfo;

typedef struct
{
  bfd_byte info[4];
  bfd_byte konst[4];
} Elf32_External_crinfo2;