ldlang.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,418 行 · 第 1/5 页

      p->real = true;
      p->local_sym_name = name;
      p->just_syms_flag = true;
      p->search_dirs_flag = false;
      break;
    case lang_input_file_is_fake_enum:
      p->filename = name;
      p->is_archive = false;
      p->real = false;
      p->local_sym_name = name;
      p->just_syms_flag = false;
      p->search_dirs_flag = false;
      break;
    case lang_input_file_is_l_enum:
      p->is_archive = true;
      p->filename = name;
      p->real = true;
      p->local_sym_name = concat ("-l", name, (const char *) NULL);
      p->just_syms_flag = false;
      p->search_dirs_flag = true;
      break;
    case lang_input_file_is_marker_enum:
      p->filename = name;
      p->is_archive = false;
      p->real = false;
      p->local_sym_name = name;
      p->just_syms_flag = false;
      p->search_dirs_flag = true;
      break;
    case lang_input_file_is_search_file_enum:
      p->filename = name;
      p->is_archive = false;
      p->real = true;
      p->local_sym_name = name;
      p->just_syms_flag = false;
      p->search_dirs_flag = true;
      break;
    case lang_input_file_is_file_enum:
      p->filename = name;
      p->is_archive = false;
      p->real = true;
      p->local_sym_name = name;
      p->just_syms_flag = false;
      p->search_dirs_flag = false;
      break;
    default:
      FAIL ();
    }
  p->the_bfd = (bfd *) NULL;
  p->asymbols = (asymbol **) NULL;
  p->next_real_file = (lang_statement_union_type *) NULL;
  p->next = (lang_statement_union_type *) NULL;
  p->symbol_count = 0;
  p->dynamic = config.dynamic_link;
  p->whole_archive = whole_archive;
  p->loaded = false;
  lang_statement_append (&input_file_chain,
			 (lang_statement_union_type *) p,
			 &p->next_real_file);
  return p;
}

lang_input_statement_type *
lang_add_input_file (name, file_type, target)
     const char *name;
     lang_input_file_enum_type file_type;
     const char *target;
{
  lang_has_input_file = true;
  return new_afile (name, file_type, target, true);
}

/* Build enough state so that the parser can build its tree.  */

void
lang_init ()
{
  obstack_begin (&stat_obstack, 1000);

  stat_ptr = &statement_list;

  lang_list_init (stat_ptr);

  lang_list_init (&input_file_chain);
  lang_list_init (&lang_output_section_statement);
  lang_list_init (&file_chain);
  first_file = lang_add_input_file ((char *) NULL,
				    lang_input_file_is_marker_enum,
				    (char *) NULL);
  abs_output_section =
    lang_output_section_statement_lookup (BFD_ABS_SECTION_NAME);

  abs_output_section->bfd_section = bfd_abs_section_ptr;

}

/*----------------------------------------------------------------------
  A region is an area of memory declared with the
  MEMORY {  name:org=exp, len=exp ... }
  syntax.

  We maintain a list of all the regions here.

  If no regions are specified in the script, then the default is used
  which is created when looked up to be the entire data space.  */

static lang_memory_region_type *lang_memory_region_list;
static lang_memory_region_type **lang_memory_region_list_tail = &lang_memory_region_list;

lang_memory_region_type *
lang_memory_region_lookup (name)
     const char *const name;
{
  lang_memory_region_type *p;

  for (p = lang_memory_region_list;
       p != (lang_memory_region_type *) NULL;
       p = p->next)
    {
      if (strcmp (p->name, name) == 0)
	{
	  return p;
	}
    }

#if 0
  /* This code used to always use the first region in the list as the
     default region.  I changed it to instead use a region
     encompassing all of memory as the default region.  This permits
     NOLOAD sections to work reasonably without requiring a region.
     People should specify what region they mean, if they really want
     a region.  */
  if (strcmp (name, "*default*") == 0)
    {
      if (lang_memory_region_list != (lang_memory_region_type *) NULL)
	{
	  return lang_memory_region_list;
	}
    }
#endif

  {
    lang_memory_region_type *new =
    (lang_memory_region_type *) stat_alloc (sizeof (lang_memory_region_type));

    new->name = xstrdup (name);
    new->next = (lang_memory_region_type *) NULL;

    *lang_memory_region_list_tail = new;
    lang_memory_region_list_tail = &new->next;
    new->origin = 0;
    new->flags = 0;
    new->not_flags = 0;
    new->length = ~(bfd_size_type) 0;
    new->current = 0;
    new->had_full_message = false;

    return new;
  }
}

static lang_memory_region_type *
lang_memory_default (section)
     asection *section;
{
  lang_memory_region_type *p;

  flagword sec_flags = section->flags;

  /* Override SEC_DATA to mean a writable section.  */
  if ((sec_flags & (SEC_ALLOC | SEC_READONLY | SEC_CODE)) == SEC_ALLOC)
    sec_flags |= SEC_DATA;

  for (p = lang_memory_region_list;
       p != (lang_memory_region_type *) NULL;
       p = p->next)
    {
      if ((p->flags & sec_flags) != 0
	  && (p->not_flags & sec_flags) == 0)
	{
	  return p;
	}
    }
  return lang_memory_region_lookup ("*default*");
}

lang_output_section_statement_type *
lang_output_section_find (name)
     const char *const name;
{
  lang_statement_union_type *u;
  lang_output_section_statement_type *lookup;

  for (u = lang_output_section_statement.head;
       u != (lang_statement_union_type *) NULL;
       u = lookup->next)
    {
      lookup = &u->output_section_statement;
      if (strcmp (name, lookup->name) == 0)
	{
	  return lookup;
	}
    }
  return (lang_output_section_statement_type *) NULL;
}

lang_output_section_statement_type *
lang_output_section_statement_lookup (name)
     const char *const name;
{
  lang_output_section_statement_type *lookup;

  lookup = lang_output_section_find (name);
  if (lookup == (lang_output_section_statement_type *) NULL)
    {

      lookup = (lang_output_section_statement_type *)
	new_stat (lang_output_section_statement, stat_ptr);
      lookup->region = (lang_memory_region_type *) NULL;
      lookup->lma_region = (lang_memory_region_type *) NULL;
      lookup->fill = 0;
      lookup->block_value = 1;
      lookup->name = name;

      lookup->next = (lang_statement_union_type *) NULL;
      lookup->bfd_section = (asection *) NULL;
      lookup->processed = false;
      lookup->sectype = normal_section;
      lookup->addr_tree = (etree_type *) NULL;
      lang_list_init (&lookup->children);

      lookup->memspec = (const char *) NULL;
      lookup->flags = 0;
      lookup->subsection_alignment = -1;
      lookup->section_alignment = -1;
      lookup->load_base = (union etree_union *) NULL;
      lookup->phdrs = NULL;

      lang_statement_append (&lang_output_section_statement,
			     (lang_statement_union_type *) lookup,
			     &lookup->next);
    }
  return lookup;
}

static void
lang_map_flags (flag)
     flagword flag;
{
  if (flag & SEC_ALLOC)
    minfo ("a");

  if (flag & SEC_CODE)
    minfo ("x");

  if (flag & SEC_READONLY)
    minfo ("r");

  if (flag & SEC_DATA)
    minfo ("w");

  if (flag & SEC_LOAD)
    minfo ("l");
}

void
lang_map ()
{
  lang_memory_region_type *m;

  minfo (_("\nMemory Configuration\n\n"));
  fprintf (config.map_file, "%-16s %-18s %-18s %s\n",
	   _("Name"), _("Origin"), _("Length"), _("Attributes"));

  for (m = lang_memory_region_list;
       m != (lang_memory_region_type *) NULL;
       m = m->next)
    {
      char buf[100];
      int len;

      fprintf (config.map_file, "%-16s ", m->name);

      sprintf_vma (buf, m->origin);
      minfo ("0x%s ", buf);
      len = strlen (buf);
      while (len < 16)
	{
	  print_space ();
	  ++len;
	}

      minfo ("0x%V", m->length);
      if (m->flags || m->not_flags)
	{
#ifndef BFD64
	  minfo ("        ");
#endif
	  if (m->flags)
	    {
	      print_space ();
	      lang_map_flags (m->flags);
	    }

	  if (m->not_flags)
	    {
	      minfo (" !");
	      lang_map_flags (m->not_flags);
	    }
	}

      print_nl ();
    }

  fprintf (config.map_file, _("\nLinker script and memory map\n\n"));

  print_statements ();
}

/* Initialize an output section.  */

static void
init_os (s)
     lang_output_section_statement_type *s;
{
  section_userdata_type *new;

  if (s->bfd_section != NULL)
    return;

  if (strcmp (s->name, DISCARD_SECTION_NAME) == 0)
    einfo (_("%P%F: Illegal use of `%s' section"), DISCARD_SECTION_NAME);

  new = ((section_userdata_type *)
	 stat_alloc (sizeof (section_userdata_type)));

  s->bfd_section = bfd_get_section_by_name (output_bfd, s->name);
  if (s->bfd_section == (asection *) NULL)
    s->bfd_section = bfd_make_section (output_bfd, s->name);
  if (s->bfd_section == (asection *) NULL)
    {
      einfo (_("%P%F: output format %s cannot represent section called %s\n"),
	     output_bfd->xvec->name, s->name);
    }
  s->bfd_section->output_section = s->bfd_section;

  /* We initialize an output sections output offset to minus its own
     vma to allow us to output a section through itself.  */
  s->bfd_section->output_offset = 0;
  get_userdata (s->bfd_section) = (PTR) new;

  /* If there is a base address, make sure that any sections it might
     mention are initialized.  */
  if (s->addr_tree != NULL)
    exp_init_os (s->addr_tree);
}

/* Make sure that all output sections mentioned in an expression are
   initialized.  */

static void
exp_init_os (exp)
     etree_type *exp;
{
  switch (exp->type.node_class)
    {
    case etree_assign:
      exp_init_os (exp->assign.src);
      break;

    case etree_binary:
      exp_init_os (exp->binary.lhs);
      exp_init_os (exp->binary.rhs);
      break;

    case etree_trinary:
      exp_init_os (exp->trinary.cond);
      exp_init_os (exp->trinary.lhs);
      exp_init_os (exp->trinary.rhs);
      break;

    case etree_unary:
      exp_init_os (exp->unary.child);
      break;

    case etree_name:
      switch (exp->type.node_code)
	{
	case ADDR:
	case LOADADDR:
	case SIZEOF:
	  {
	    lang_output_section_statement_type *os;

	    os = lang_output_section_find (exp->name.name);
	    if (os != NULL && os->bfd_section == NULL)
	      init_os (os);
	  }
	}
      break;

    default:
      break;
    }
}

/* Sections marked with the SEC_LINK_ONCE flag should only be linked
   once into the output.  This routine checks each section, and
   arrange to discard it if a section of the same name has already
   been linked.  If the section has COMDAT information, then it uses
   that to decide whether the section should be included.  This code
   assumes that all relevant sections have the SEC_LINK_ONCE flag set;
   that is, it does not depend solely upon the section name.
   section_already_linked is called via bfd_map_over_sections.  */

/* This is the shape of the elements inside the already_linked hash
   table. It maps a name onto a list of already_linked elements with
   the same name.  It's possible to get more than one element in a
   list if the COMDAT sections have different names.  */

struct already_linked_hash_entry
{
  struct bfd_hash_entry root;
  struct already_linked *entry;
};

struct already_linked
{
  struct already_linked *next;
  asection *sec;
};

/* The hash table.  */

static struct bfd_hash_table already_linked_table;

static void
section_already_linked (abfd, sec, data)
     bfd *abfd;
     asection *sec;
     PTR data;
{
  lang_input_statement_type *entry = (lang_input_statement_type *) data;
  flagword flags;
  const char *name;
  struct already_linked *l;
  struct already_linked_hash_entry *already_linked_list;

  /* If we are only reading symbols from this object, then we want to
     discard all sections.  */
  if (entry->just_syms_flag)
    {
      sec->output_section = bfd_abs_section_ptr;
      sec->output_offset = sec->vma;
      return;
    }

  flags = bfd_get_section_flags (abfd, sec);

  if ((flags & SEC_LINK_ONCE) == 0)
    return;

  /* FIXME: When doing a relocatable link, we may have trouble
     copying relocations in other sections that refer to local symbols
     in the section being discarded.  Those relocations will have to
     be converted somehow; as of this writing I'm not sure that any of
     the backends handle that correctly.

     It is tempting to instead not discard link once sections when
     doing a relocatable link (technically, they should be discarded
     whenever we are building constructors).  However, that fails,
     because the linker winds up combining all the link once sections
     into a single large link once section, which defeats the purpose
     of having link once sections in the first place.

     Also, not merging link once sections in a relocatable link
     causes trouble for MIPS ELF, which relies in link once semantics
     to handle the .reginfo section correctly.  */

  name = bfd_get_section_name (abfd, sec);

  already_linked_list =
    ((struct already_linked_hash_entry *)
     bfd_hash_lookup (&already_linked_table, name, true, false));