binutils-gdb/bfd/elf32-mt.c

/* Morpho Technologies MT specific support for 32-bit ELF
   Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012
   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 3 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 "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf/mt.h"

/* Prototypes.  */
static reloc_howto_type * mt_reloc_type_lookup 
  (bfd *, bfd_reloc_code_real_type);

static void mt_info_to_howto_rela
  (bfd *, arelent *, Elf_Internal_Rela *);

static bfd_reloc_status_type mt_elf_relocate_hi16
  (bfd *, Elf_Internal_Rela *, bfd_byte *, bfd_vma);

static bfd_reloc_status_type mt_final_link_relocate
  (reloc_howto_type *, bfd *, asection *, bfd_byte *, 
   Elf_Internal_Rela *, bfd_vma);

static bfd_boolean mt_elf_relocate_section
  (bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *, 
   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **);

/* Relocation tables.  */
static reloc_howto_type mt_elf_howto_table [] =
{
  /* This reloc does nothing.  */
  HOWTO (R_MT_NONE,           /* type */
          0,                      /* rightshift */ 
          2,                      /* size (0 = byte, 1 = short, 2 = long) */ 
          32,                     /* bitsize */
          FALSE,                  /* pc_relative */ 
          0,                      /* bitpos */ 
          complain_overflow_dont, /* complain_on_overflow */ 
          bfd_elf_generic_reloc,  /* special_function */ 
          "R_MT_NONE",          /* name */ 
          FALSE,                  /* partial_inplace */ 
          0 ,                     /* src_mask */ 
          0,                      /* dst_mask */ 
          FALSE),                 /* pcrel_offset */

  /* A 16 bit absolute relocation.  */
  HOWTO (R_MT_16,             /* type */
          0,                      /* rightshift */ 
          2,                      /* size (0 = byte, 1 = short, 2 = long) */ 
          16,                     /* bitsize */
          FALSE,                  /* pc_relative */ 
          0,                      /* bitpos */ 
          complain_overflow_dont, /* complain_on_overflow */ 
          bfd_elf_generic_reloc,  /* special_function */ 
          "R_MT_16",            /* name */ 
          FALSE,                  /* partial_inplace */ 
          0 ,                     /* src_mask */ 
          0xffff,                 /* dst_mask */ 
          FALSE),                 /* pcrel_offset */

  /* A 32 bit absolute relocation.  */
  HOWTO (R_MT_32,             /* type */
          0,                      /* rightshift */ 
          2,                      /* size (0 = byte, 1 = short, 2 = long) */ 
          32,                     /* bitsize */
          FALSE,                  /* pc_relative */ 
          0,                      /* bitpos */ 
          complain_overflow_dont, /* complain_on_overflow */ 
          bfd_elf_generic_reloc,  /* special_function */ 
          "R_MT_32",            /* name */ 
          FALSE,                  /* partial_inplace */ 
          0 ,                     /* src_mask */ 
          0xffffffff,             /* dst_mask */ 
          FALSE),                 /* pcrel_offset */

  /* A 32 bit pc-relative relocation.  */
  HOWTO (R_MT_32_PCREL,       /* type */
          0,                      /* rightshift */ 
          2,                      /* size (0 = byte, 1 = short, 2 = long) */ 
          32,                     /* bitsize */
          TRUE,                   /* pc_relative */ 
          0,                      /* bitpos */ 
          complain_overflow_dont, /* complain_on_overflow */ 
          bfd_elf_generic_reloc,  /* special_function */ 
          "R_MT_32_PCREL",    /* name */ 
          FALSE,                  /* partial_inplace */ 
          0 ,                     /* src_mask */ 
          0xffffffff,             /* dst_mask */ 
          TRUE),                  /* pcrel_offset */

  /* A 16 bit pc-relative relocation.  */
  HOWTO (R_MT_PC16,           /* type */
          0,                      /* rightshift */ 
          2,                      /* size (0 = byte, 1 = short, 2 = long) */ 
          16,                     /* bitsize */
          TRUE,                   /* pc_relative */ 
          0,                      /* bitpos */ 
          complain_overflow_signed, /* complain_on_overflow */ 
          bfd_elf_generic_reloc,  /* special_function */ 
          "R_MT_PC16",          /* name */ 
          FALSE,                  /* partial_inplace */ 
          0,                      /* src_mask */ 
          0xffff,                 /* dst_mask */ 
          TRUE),                  /* pcrel_offset */

  /* high 16 bits of symbol value.  */
  HOWTO (R_MT_HI16,          /* type */
         0,                     /* rightshift */
         2,                     /* size (0 = byte, 1 = short, 2 = long) */
         16,                    /* bitsize */
         FALSE,                 /* pc_relative */
         0,                     /* bitpos */
         complain_overflow_dont, /* complain_on_overflow */
         bfd_elf_generic_reloc, /* special_function */
         "R_MT_HI16",        /* name */
         FALSE,                  /* partial_inplace */
         0xffff0000,            /* src_mask */
         0xffff0000,            /* dst_mask */
         FALSE),                /* pcrel_offset */

  /* Low 16 bits of symbol value.  */
  HOWTO (R_MT_LO16,          /* type */
         0,                     /* rightshift */
         2,                     /* size (0 = byte, 1 = short, 2 = long) */
         16,                    /* bitsize */
         FALSE,                 /* pc_relative */
         0,                     /* bitpos */
         complain_overflow_dont, /* complain_on_overflow */
         bfd_elf_generic_reloc, /* special_function */
         "R_MT_LO16",        /* name */
         FALSE,                  /* partial_inplace */
         0xffff,                /* src_mask */
         0xffff,                /* dst_mask */
         FALSE),                /* pcrel_offset */
};

/* Map BFD reloc types to MT ELF reloc types.  */

static reloc_howto_type *
mt_reloc_type_lookup
    (bfd *                    abfd ATTRIBUTE_UNUSED,
     bfd_reloc_code_real_type code)
{
  /* Note that the mt_elf_howto_table is indxed by the R_
     constants.  Thus, the order that the howto records appear in the
     table *must* match the order of the relocation types defined in
     include/elf/mt.h.  */

  switch (code)
    {
    case BFD_RELOC_NONE:
      return &mt_elf_howto_table[ (int) R_MT_NONE];
    case BFD_RELOC_16:
      return &mt_elf_howto_table[ (int) R_MT_16];
    case BFD_RELOC_32:
      return &mt_elf_howto_table[ (int) R_MT_32];
    case BFD_RELOC_32_PCREL:
      return &mt_elf_howto_table[ (int) R_MT_32_PCREL];
    case BFD_RELOC_16_PCREL:
      return &mt_elf_howto_table[ (int) R_MT_PC16];
    case BFD_RELOC_HI16:
      return &mt_elf_howto_table[ (int) R_MT_HI16];
    case BFD_RELOC_LO16:
      return &mt_elf_howto_table[ (int) R_MT_LO16];

    default:
      /* Pacify gcc -Wall.  */
      return NULL;
    }
  return NULL;
}

static reloc_howto_type *
mt_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
		      const char *r_name)
{
  unsigned int i;

  for (i = 0;
       i < sizeof (mt_elf_howto_table) / sizeof (mt_elf_howto_table[0]);
       i++)
    if (mt_elf_howto_table[i].name != NULL
	&& strcasecmp (mt_elf_howto_table[i].name, r_name) == 0)
      return &mt_elf_howto_table[i];

  return NULL;
}

bfd_reloc_status_type
mt_elf_relocate_hi16
    (bfd *               input_bfd,
     Elf_Internal_Rela * relhi,
     bfd_byte *          contents,
     bfd_vma             value)
{
  bfd_vma insn;

  insn = bfd_get_32 (input_bfd, contents + relhi->r_offset);

  value += relhi->r_addend;
  value >>= 16;
  insn = ((insn & ~0xFFFF) | value);

  bfd_put_32 (input_bfd, insn, contents + relhi->r_offset);
  return bfd_reloc_ok;
}

/* XXX: The following code is the result of a cut&paste.  This unfortunate
   practice is very widespread in the various target back-end files.  */

/* Set the howto pointer for a MT ELF reloc.  */

static void
mt_info_to_howto_rela
    (bfd *               abfd ATTRIBUTE_UNUSED,
     arelent *           cache_ptr,
     Elf_Internal_Rela * dst)
{
  unsigned int r_type;

  r_type = ELF32_R_TYPE (dst->r_info);
  cache_ptr->howto = & mt_elf_howto_table [r_type];
}

/* Perform a single relocation.  By default we use the standard BFD
   routines.  */

static bfd_reloc_status_type
mt_final_link_relocate
    (reloc_howto_type *  howto,
     bfd *               input_bfd,
     asection *          input_section,
     bfd_byte *          contents,
     Elf_Internal_Rela * rel,
     bfd_vma             relocation)
{
  return _bfd_final_link_relocate (howto, input_bfd, input_section,
				   contents, rel->r_offset,
				   relocation, rel->r_addend);
}

/* Relocate a MT ELF section.
   There is some attempt to make this function usable for many architectures,
   both USE_REL and USE_RELA ['twould be nice if such a critter existed],
   if only to serve as a learning tool.

   The RELOCATE_SECTION function is called by the new ELF backend linker
   to handle the relocations for a section.

   The relocs are always passed as Rela structures; if the section
   actually uses Rel structures, the r_addend field will always be
   zero.

   This function is responsible for adjusting the section contents as
   necessary, and (if using Rela relocs and generating a relocatable
   output file) adjusting the reloc addend as necessary.

   This function does not have to worry about setting the reloc
   address or the reloc symbol index.

   LOCAL_SYMS is a pointer to the swapped in local symbols.

   LOCAL_SECTIONS is an array giving the section in the input file
   corresponding to the st_shndx field of each local symbol.

   The global hash table entry for the global symbols can be found
   via elf_sym_hashes (input_bfd).

   When generating relocatable output, this function must handle
   STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
   going to be the section symbol corresponding to the output
   section, which means that the addend must be adjusted
   accordingly.  */

static bfd_boolean
mt_elf_relocate_section
    (bfd *                   output_bfd ATTRIBUTE_UNUSED,
     struct bfd_link_info *  info,
     bfd *                   input_bfd,
     asection *              input_section,
     bfd_byte *              contents,
     Elf_Internal_Rela *     relocs,
     Elf_Internal_Sym *      local_syms,
     asection **             local_sections)
{
  Elf_Internal_Shdr *           symtab_hdr;
  struct elf_link_hash_entry ** sym_hashes;
  Elf_Internal_Rela *           rel;
  Elf_Internal_Rela *           relend;

  symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (input_bfd);
  relend     = relocs + input_section->reloc_count;

  for (rel = relocs; rel < relend; rel ++)
    {
      reloc_howto_type *           howto;
      unsigned long                r_symndx;
      Elf_Internal_Sym *           sym;
      asection *                   sec;
      struct elf_link_hash_entry * h;
      bfd_vma                      relocation;
      bfd_reloc_status_type        r;
      const char *                 name = NULL;
      int                          r_type;
      
      r_type = ELF32_R_TYPE (rel->r_info);

      r_symndx = ELF32_R_SYM (rel->r_info);

      howto  = mt_elf_howto_table + ELF32_R_TYPE (rel->r_info);
      h      = NULL;
      sym    = NULL;
      sec    = NULL;
      
      if (r_symndx < symtab_hdr->sh_info)
	{
	  sym = local_syms + r_symndx;
	  sec = local_sections [r_symndx];
	  relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
	  
	  name = bfd_elf_string_from_elf_section
	    (input_bfd, symtab_hdr->sh_link, sym->st_name);
	  name = (name == NULL) ? bfd_section_name (input_bfd, sec) : name;
	}
      else
	{
	  bfd_boolean unresolved_reloc;
	  bfd_boolean warned;

	  RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
				   r_symndx, symtab_hdr, sym_hashes,
				   h, sec, relocation,
				   unresolved_reloc, warned);

	  name = h->root.root.string;
	}

      if (sec != NULL && discarded_section (sec))
	RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
					 rel, 1, relend, howto, 0, contents);

      if (info->relocatable)
	continue;

      /* Finally, the sole MT-specific part.  */
      switch (r_type)
        {
        case R_MT_HI16:
          r = mt_elf_relocate_hi16 (input_bfd, rel, contents, relocation);
          break;
	default:
          r = mt_final_link_relocate (howto, input_bfd, input_section,
		        		  contents, rel, relocation);
          break;
        }


      if (r != bfd_reloc_ok)
	{
	  const char * msg = (const char *) NULL;

	  switch (r)
	    {
	    case bfd_reloc_overflow:
	      r = info->callbacks->reloc_overflow
		(info, (h ? &h->root : NULL), name, howto->name, (bfd_vma) 0,
		 input_bfd, input_section, rel->r_offset);
	      break;
	      
	    case bfd_reloc_undefined:
	      r = info->callbacks->undefined_symbol
		(info, name, input_bfd, input_section, rel->r_offset, TRUE);
	      break;
	      
	    case bfd_reloc_outofrange:
	      msg = _("internal error: out of range error");
	      break;

	    case bfd_reloc_dangerous:
	      msg = _("internal error: dangerous relocation");
	      break;

	    default:
	      msg = _("internal error: unknown error");
	      break;
	    }

	  if (msg)
	    r = info->callbacks->warning
	      (info, msg, name, input_bfd, input_section, rel->r_offset);

	  if (! r)
	    return FALSE;
	}
    }

  return TRUE;
}

/* Look through the relocs for a section during the first phase.
   Since we don't do .gots or .plts, we just need to consider the
   virtual table relocs for gc.  */
 
static bfd_boolean
mt_elf_check_relocs
    (bfd *                     abfd,
     struct bfd_link_info *    info,
     asection *                sec,
     const Elf_Internal_Rela * relocs)
{
  Elf_Internal_Shdr *           symtab_hdr;
  struct elf_link_hash_entry ** sym_hashes;
  const Elf_Internal_Rela *     rel;
  const Elf_Internal_Rela *     rel_end;
  
  if (info->relocatable)
    return TRUE;
  
  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  
  rel_end = relocs + sec->reloc_count;
  for (rel = relocs; rel < rel_end; rel++)
    {
      struct elf_link_hash_entry *h;
      unsigned long r_symndx;
      
      r_symndx = ELF32_R_SYM (rel->r_info);
      if (r_symndx < symtab_hdr->sh_info)
        h = NULL;
      else
	{
	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
	  while (h->root.type == bfd_link_hash_indirect
		 || h->root.type == bfd_link_hash_warning)
	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
	}
    }

  return TRUE;
}

/* Return the MACH for an e_flags value.  */

static int
elf32_mt_machine (bfd *abfd)
{
  switch (elf_elfheader (abfd)->e_flags & EF_MT_CPU_MASK)
    {
    case EF_MT_CPU_MRISC:	return bfd_mach_ms1;
    case EF_MT_CPU_MRISC2:	return bfd_mach_mrisc2;
    case EF_MT_CPU_MS2:		return bfd_mach_ms2;
    }

  return bfd_mach_ms1;
}

static bfd_boolean
mt_elf_object_p (bfd * abfd)
{
  bfd_default_set_arch_mach (abfd, bfd_arch_mt, elf32_mt_machine (abfd));

  return TRUE;
}

/* Function to set the ELF flag bits.  */

static bfd_boolean
mt_elf_set_private_flags (bfd *    abfd,
			   flagword flags)
{
  elf_elfheader (abfd)->e_flags = flags;
  elf_flags_init (abfd) = TRUE;
  return TRUE;
}

static bfd_boolean
mt_elf_copy_private_bfd_data (bfd * ibfd, bfd * obfd)
{
  if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
    return TRUE;
  
  BFD_ASSERT (!elf_flags_init (obfd)
	      || elf_elfheader (obfd)->e_flags == elf_elfheader (ibfd)->e_flags);

  elf_elfheader (obfd)->e_flags = elf_elfheader (ibfd)->e_flags;
  elf_flags_init (obfd) = TRUE;

  /* Copy object attributes.  */
  _bfd_elf_copy_obj_attributes (ibfd, obfd);

  return TRUE;
}

/* Merge backend specific data from an object file to the output
   object file when linking.  */

static bfd_boolean
mt_elf_merge_private_bfd_data (bfd * ibfd, bfd * obfd)
{
  flagword     old_flags, new_flags;
  bfd_boolean  ok = TRUE;

  /* Check if we have the same endianness.  */
  if (_bfd_generic_verify_endian_match (ibfd, obfd) == FALSE)
    return FALSE;

  /* If they're not both mt, then merging is meaningless, so just
     don't do it.  */
  if (strcmp (ibfd->arch_info->arch_name, "mt") != 0)
    return TRUE;
  if (strcmp (obfd->arch_info->arch_name, "mt") != 0)
    return TRUE;

  new_flags = elf_elfheader (ibfd)->e_flags;
  old_flags = elf_elfheader (obfd)->e_flags;

#ifdef DEBUG
  _bfd_error_handler ("%B: old_flags = 0x%.8lx, new_flags = 0x%.8lx, init = %s",
		      ibfd, old_flags, new_flags, elf_flags_init (obfd) ? "yes" : "no");
#endif

  if (!elf_flags_init (obfd))
    {
      old_flags = new_flags;
      elf_flags_init (obfd) = TRUE;
    }
  else if ((new_flags & EF_MT_CPU_MASK) != (old_flags & EF_MT_CPU_MASK))
    {
      /* CPU has changed.  This is invalid, because MRISC, MRISC2 and
	 MS2 are not subsets of each other.   */
      ok = FALSE;
    }
  
  if (ok)
    {
      obfd->arch_info = ibfd->arch_info;
      elf_elfheader (obfd)->e_flags = old_flags;
    }

  return ok;
}

static bfd_boolean
mt_elf_print_private_bfd_data (bfd * abfd, void * ptr)
{
  FILE *   file = (FILE *) ptr;
  flagword flags;

  BFD_ASSERT (abfd != NULL && ptr != NULL);
  
  /* Print normal ELF private data.  */
  _bfd_elf_print_private_bfd_data (abfd, ptr);

  flags = elf_elfheader (abfd)->e_flags;
  fprintf (file, _("private flags = 0x%lx:"), (unsigned long) flags);

  switch (flags & EF_MT_CPU_MASK)
    {
    default:
    case EF_MT_CPU_MRISC:   fprintf (file, " ms1-16-002");	break;
    case EF_MT_CPU_MRISC2:  fprintf (file, " ms1-16-003");	break;
    case EF_MT_CPU_MS2:     fprintf (file, " ms2");	break;
    }

  fputc ('\n', file);

  return TRUE;
}


#define TARGET_BIG_SYM	 bfd_elf32_mt_vec
#define TARGET_BIG_NAME  "elf32-mt"

#define ELF_ARCH	 bfd_arch_mt
#define ELF_MACHINE_CODE EM_MT
#define ELF_MAXPAGESIZE  1 /* No pages on the MT.  */

#define elf_info_to_howto_rel			NULL
#define elf_info_to_howto			mt_info_to_howto_rela

#define elf_backend_relocate_section		mt_elf_relocate_section

#define bfd_elf32_bfd_reloc_type_lookup	        mt_reloc_type_lookup
#define bfd_elf32_bfd_reloc_name_lookup   mt_reloc_name_lookup

#define elf_backend_check_relocs                mt_elf_check_relocs
#define elf_backend_object_p		        mt_elf_object_p
#define elf_backend_rela_normal			1

#define elf_backend_can_gc_sections		1

#define bfd_elf32_bfd_set_private_flags		mt_elf_set_private_flags
#define bfd_elf32_bfd_copy_private_bfd_data	mt_elf_copy_private_bfd_data
#define bfd_elf32_bfd_merge_private_bfd_data	mt_elf_merge_private_bfd_data
#define bfd_elf32_bfd_print_private_bfd_data	mt_elf_print_private_bfd_data

#include "elf32-target.h"