linker.c

基于4个mips核的noc设计

	      h->type = bfd_link_hash_defined;
	    h->u.def.section = section;
	    h->u.def.value = value;

	    /* If we have been asked to, we act like collect2 and
	       identify all functions that might be global
	       constructors and destructors and pass them up in a
	       callback.  We only do this for certain object file
	       types, since many object file types can handle this
	       automatically.  */
	    if (collect && name[0] == '_')
	      {
		const char *s;

		/* A constructor or destructor name starts like this:
		   _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
		   the second are the same character (we accept any
		   character there, in case a new object file format
		   comes along with even worse naming restrictions).  */

#define CONS_PREFIX "GLOBAL_"
#define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)

		s = name + 1;
		while (*s == '_')
		  ++s;
		if (s[0] == 'G'
		    && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0)
		  {
		    char c;

		    c = s[CONS_PREFIX_LEN + 1];
		    if ((c == 'I' || c == 'D')
			&& s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
		      {
			/* If this is a definition of a symbol which
                           was previously weakly defined, we are in
                           trouble.  We have already added a
                           constructor entry for the weak defined
                           symbol, and now we are trying to add one
                           for the new symbol.  Fortunately, this case
                           should never arise in practice.  */
			if (oldtype == bfd_link_hash_defweak)
			  abort ();

			if (! ((*info->callbacks->constructor)
			       (info,
				c == 'I' ? true : false,
				h->root.string, abfd, section, value)))
			  return false;
		      }
		  }
	      }
	  }

	  break;

	case COM:
	  /* We have found a common definition for a symbol.  */
	  if (h->type == bfd_link_hash_new)
	    bfd_link_add_undef (info->hash, h);
	  h->type = bfd_link_hash_common;
	  h->u.c.p =
	    ((struct bfd_link_hash_common_entry *)
	     bfd_hash_allocate (&info->hash->table,
				sizeof (struct bfd_link_hash_common_entry)));
	  if (h->u.c.p == NULL)
	    return false;

	  h->u.c.size = value;

	  /* Select a default alignment based on the size.  This may
             be overridden by the caller.  */
	  {
	    unsigned int power;

	    power = bfd_log2 (value);
	    if (power > 4)
	      power = 4;
	    h->u.c.p->alignment_power = power;
	  }

	  /* The section of a common symbol is only used if the common
             symbol is actually allocated.  It basically provides a
             hook for the linker script to decide which output section
             the common symbols should be put in.  In most cases, the
             section of a common symbol will be bfd_com_section_ptr,
             the code here will choose a common symbol section named
             "COMMON", and the linker script will contain *(COMMON) in
             the appropriate place.  A few targets use separate common
             sections for small symbols, and they require special
             handling.  */
	  if (section == bfd_com_section_ptr)
	    {
	      h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
	      h->u.c.p->section->flags = SEC_ALLOC;
	    }
	  else if (section->owner != abfd)
	    {
	      h->u.c.p->section = bfd_make_section_old_way (abfd,
							    section->name);
	      h->u.c.p->section->flags = SEC_ALLOC;
	    }
	  else
	    h->u.c.p->section = section;
	  break;

	case REF:
	  /* A reference to a defined symbol.  */
	  if (h->next == NULL && info->hash->undefs_tail != h)
	    h->next = h;
	  break;

	case BIG:
	  /* We have found a common definition for a symbol which
	     already had a common definition.  Use the maximum of the
	     two sizes.  */
	  BFD_ASSERT (h->type == bfd_link_hash_common);
	  if (! ((*info->callbacks->multiple_common)
		 (info, h->root.string,
		  h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
		  abfd, bfd_link_hash_common, value)))
	    return false;
	  if (value > h->u.c.size)
	    {
	      unsigned int power;

	      h->u.c.size = value;

	      /* Select a default alignment based on the size.  This may
		 be overridden by the caller.  */
	      power = bfd_log2 (value);
	      if (power > 4)
		power = 4;
	      h->u.c.p->alignment_power = power;
	    }
	  break;

	case CREF:
	  {
	    bfd *obfd;

	    /* We have found a common definition for a symbol which
	       was already defined.  FIXME: It would nice if we could
	       report the BFD which defined an indirect symbol, but we
	       don't have anywhere to store the information.  */
	    if (h->type == bfd_link_hash_defined
		|| h->type == bfd_link_hash_defweak)
	      obfd = h->u.def.section->owner;
	    else
	      obfd = NULL;
	    if (! ((*info->callbacks->multiple_common)
		   (info, h->root.string, obfd, h->type, (bfd_vma) 0,
		    abfd, bfd_link_hash_common, value)))
	      return false;
	  }
	  break;

	case MIND:
	  /* Multiple indirect symbols.  This is OK if they both point
	     to the same symbol.  */
	  if (strcmp (h->u.i.link->root.string, string) == 0)
	    break;
	  /* Fall through.  */
	case MDEF:
	  /* Handle a multiple definition.  */
	  {
	    asection *msec = NULL;
	    bfd_vma mval = 0;

	    switch (h->type)
	      {
	      case bfd_link_hash_defined:
		msec = h->u.def.section;
		mval = h->u.def.value;
		break;
	      case bfd_link_hash_indirect:
		msec = bfd_ind_section_ptr;
		mval = 0;
		break;
	      default:
		abort ();
	      }

	    /* Ignore a redefinition of an absolute symbol to the same
               value; it's harmless.  */
	    if (h->type == bfd_link_hash_defined
		&& bfd_is_abs_section (msec)
		&& bfd_is_abs_section (section)
		&& value == mval)
	      break;

	    if (! ((*info->callbacks->multiple_definition)
		   (info, h->root.string, msec->owner, msec, mval, abfd,
		    section, value)))
	      return false;
	  }
	  break;

	case CIND:
	  /* Create an indirect symbol from an existing common symbol.  */
	  BFD_ASSERT (h->type == bfd_link_hash_common);
	  if (! ((*info->callbacks->multiple_common)
		 (info, h->root.string,
		  h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
		  abfd, bfd_link_hash_indirect, (bfd_vma) 0)))
	    return false;
	  /* Fall through.  */
	case IND:
	  /* Create an indirect symbol.  */
	  {
	    struct bfd_link_hash_entry *inh;

	    /* STRING is the name of the symbol we want to indirect
	       to.  */
	    inh = bfd_wrapped_link_hash_lookup (abfd, info, string, true,
						copy, false);
	    if (inh == (struct bfd_link_hash_entry *) NULL)
	      return false;
	    if (inh->type == bfd_link_hash_indirect
		&& inh->u.i.link == h)
	      {
		(*_bfd_error_handler)
		  (_("%s: indirect symbol `%s' to `%s' is a loop"),  
		   bfd_get_filename (abfd), name, string);
		bfd_set_error (bfd_error_invalid_operation);
		return false;
	      }
	    if (inh->type == bfd_link_hash_new)
	      {
		inh->type = bfd_link_hash_undefined;
		inh->u.undef.abfd = abfd;
		bfd_link_add_undef (info->hash, inh);
	      }

	    /* If the indirect symbol has been referenced, we need to
	       push the reference down to the symbol we are
	       referencing.  */
	    if (h->type != bfd_link_hash_new)
	      {
		row = UNDEF_ROW;
		cycle = true;
	      }

	    h->type = bfd_link_hash_indirect;
	    h->u.i.link = inh;
	  }
	  break;

	case SET:
	  /* Add an entry to a set.  */
	  if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
						abfd, section, value))
	    return false;
	  break;

	case WARNC:
	  /* Issue a warning and cycle.  */
	  if (h->u.i.warning != NULL)
	    {
	      if (! (*info->callbacks->warning) (info, h->u.i.warning,
						 h->root.string, abfd,
						 (asection *) NULL,
						 (bfd_vma) 0))
		return false;
	      /* Only issue a warning once.  */
	      h->u.i.warning = NULL;
	    }
	  /* Fall through.  */
	case CYCLE:
	  /* Try again with the referenced symbol.  */
	  h = h->u.i.link;
	  cycle = true;
	  break;

	case REFC:
	  /* A reference to an indirect symbol.  */
	  if (h->next == NULL && info->hash->undefs_tail != h)
	    h->next = h;
	  h = h->u.i.link;
	  cycle = true;
	  break;

	case WARN:
	  /* Issue a warning.  */
	  if (! (*info->callbacks->warning) (info, string, h->root.string,
					     hash_entry_bfd (h),
					     (asection *) NULL, (bfd_vma) 0))
	    return false;
	  break;

	case CWARN:
	  /* Warn if this symbol has been referenced already,
	     otherwise add a warning.  A symbol has been referenced if
	     the next field is not NULL, or it is the tail of the
	     undefined symbol list.  The REF case above helps to
	     ensure this.  */
	  if (h->next != NULL || info->hash->undefs_tail == h)
	    {
	      if (! (*info->callbacks->warning) (info, string, h->root.string,
						 hash_entry_bfd (h),
						 (asection *) NULL,
						 (bfd_vma) 0))
		return false;
	      break;
	    }
	  /* Fall through.  */
	case MWARN:
	  /* Make a warning symbol.  */
	  {
	    struct bfd_link_hash_entry *sub;

	    /* STRING is the warning to give.  */
	    sub = ((struct bfd_link_hash_entry *)
		   ((*info->hash->table.newfunc)
		    ((struct bfd_hash_entry *) NULL, &info->hash->table,
		     h->root.string)));
	    if (sub == NULL)
	      return false;
	    *sub = *h;
	    sub->type = bfd_link_hash_warning;
	    sub->u.i.link = h;
	    if (! copy)
	      sub->u.i.warning = string;
	    else
	      {
		char *w;

		w = bfd_hash_allocate (&info->hash->table,
				       strlen (string) + 1);
		if (w == NULL)
		  return false;
		strcpy (w, string);
		sub->u.i.warning = w;
	      }

	    bfd_hash_replace (&info->hash->table,
			      (struct bfd_hash_entry *) h,
			      (struct bfd_hash_entry *) sub);
	    if (hashp != NULL)
	      *hashp = sub;
	  }
	  break;
	}
    }
  while (cycle);

  return true;
}

/* Generic final link routine.  */

boolean
_bfd_generic_final_link (abfd, info)
     bfd *abfd;
     struct bfd_link_info *info;
{
  bfd *sub;
  asection *o;
  struct bfd_link_order *p;
  size_t outsymalloc;
  struct generic_write_global_symbol_info wginfo;

  bfd_get_outsymbols (abfd) = (asymbol **) NULL;
  bfd_get_symcount (abfd) = 0;
  outsymalloc = 0;

  /* Mark all sections which will be included in the output file.  */
  for (o = abfd->sections; o != NULL; o = o->next)
    for (p = o->link_order_head; p != NULL; p = p->next)
      if (p->type == bfd_indirect_link_order)
	p->u.indirect.section->linker_mark = true;

  /* Build the output symbol table.  */
  for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next)
    if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
      return false;

  /* Accumulate the global symbols.  */
  wginfo.info = info;
  wginfo.output_bfd = abfd;
  wginfo.psymalloc = &outsymalloc;
  _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
				   _bfd_generic_link_write_global_symbol,
				   (PTR) &wginfo);

  /* Make sure we have a trailing NULL pointer on OUTSYMBOLS.  We
     shouldn't really need one, since we have SYMCOUNT, but some old
     code still expects one.  */
  if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
    return false;

  if (info->relocateable)
    {
      /* Allocate space for the output relocs for each section.  */
      for (o = abfd->se