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# This shell script emits a C file. -*- C -*-

#   Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011

#   Free Software Foundation, Inc.

#

# This file is part of the GNU Binutils.

#

# 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., 51 Franklin Street - Fifth Floor, Boston,

# MA 02110-1301, USA.

#

# This file is sourced from elf32.em, and defines extra xtensa-elf

# specific routines.

#

fragment <

#include 

#include "../bfd/elf-bfd.h"

#include "../bfd/libbfd.h"

#include "elf/xtensa.h"

#include "bfd.h"

/* Provide default values for new configuration settings.  */

#ifndef XSHAL_ABI

#define XSHAL_ABI 0

#endif

static void xtensa_wild_group_interleave (lang_statement_union_type *);

static void xtensa_colocate_output_literals (lang_statement_union_type *);

static void xtensa_strip_inconsistent_linkonce_sections

  (lang_statement_list_type *);

/* This number is irrelevant until we turn on use_literal_pages */

static bfd_vma xtensa_page_power = 12; /* 4K pages.  */

/* To force a page break between literals and text, change

   xtensa_use_literal_pages to "TRUE".  */

static bfd_boolean xtensa_use_literal_pages = FALSE;

#define EXTRA_VALIDATION 0

static char *

elf_xtensa_choose_target (int argc ATTRIBUTE_UNUSED,

                          char **argv ATTRIBUTE_UNUSED)

{

  if (XCHAL_HAVE_BE)

    return "${BIG_OUTPUT_FORMAT}";

  else

    return "${LITTLE_OUTPUT_FORMAT}";

}

static void

elf_xtensa_before_parse (void)

{

  /* Just call the default hook.... Tensilica's version of this function

     does some other work that isn't relevant here.  */

  gld${EMULATION_NAME}_before_parse ();

}

static void

remove_section (bfd *abfd, asection *os)

{

  asection **spp;

  for (spp = &abfd->sections; *spp; spp = &(*spp)->next)

    if (*spp == os)

      {

        *spp = os->next;

        os->owner->section_count--;

        break;

      }

}

static bfd_boolean

replace_insn_sec_with_prop_sec (bfd *abfd,

                                const char *insn_sec_name,

                                const char *prop_sec_name,

                                char **error_message)

{

  asection *insn_sec;

  asection *prop_sec;

  bfd_byte *prop_contents = NULL;

  bfd_byte *insn_contents = NULL;

  unsigned entry_count;

  unsigned entry;

  Elf_Internal_Shdr *rel_hdr;

  Elf_Internal_Rela *internal_relocs = NULL;

  unsigned reloc_count;

  *error_message = "";

  insn_sec = bfd_get_section_by_name (abfd, insn_sec_name);

  if (insn_sec == NULL)

    return TRUE;

  entry_count = insn_sec->size / 8;

  prop_sec = bfd_get_section_by_name (abfd, prop_sec_name);

  if (prop_sec != NULL && insn_sec != NULL)

    {

      *error_message = _("file already has property tables");

      return FALSE;

    }

  if (insn_sec->size != 0)

    {

      insn_contents = (bfd_byte *) bfd_malloc (insn_sec->size);

      if (insn_contents == NULL)

        {

          *error_message = _("out of memory");

          goto cleanup;

        }

      if (! bfd_get_section_contents (abfd, insn_sec, insn_contents,

                                      (file_ptr) 0, insn_sec->size))

        {

          *error_message = _("failed to read section contents");

          goto cleanup;

        }

    }

  /* Create a property table section for it.  */

  prop_sec_name = strdup (prop_sec_name);

  prop_sec = bfd_make_section_with_flags

    (abfd, prop_sec_name, bfd_get_section_flags (abfd, insn_sec));

  if (prop_sec == NULL

      || ! bfd_set_section_alignment (abfd, prop_sec, 2))

    {

      *error_message = _("could not create new section");

      goto cleanup;

    }

  prop_sec->size = entry_count * 12;

  prop_contents = (bfd_byte *) bfd_zalloc (abfd, prop_sec->size);

  elf_section_data (prop_sec)->this_hdr.contents = prop_contents;

  /* The entry size and size must be set to allow the linker to compute

     the number of relocations since it does not use reloc_count.  */

  rel_hdr = _bfd_elf_single_rel_hdr (prop_sec);

  rel_hdr->sh_entsize = sizeof (Elf32_External_Rela);

  rel_hdr->sh_size = _bfd_elf_single_rel_hdr (insn_sec)->sh_size;

  if (prop_contents == NULL && prop_sec->size != 0)

    {

      *error_message = _("could not allocate section contents");

      goto cleanup;

    }

  /* Read the relocations.  */

  reloc_count = insn_sec->reloc_count;

  if (reloc_count != 0)

    {

      /* If there is already an internal_reloc, then save it so that the

         read_relocs function freshly allocates a copy.  */

      Elf_Internal_Rela *saved_relocs = elf_section_data (insn_sec)->relocs;

      elf_section_data (insn_sec)->relocs = NULL;

      internal_relocs =

        _bfd_elf_link_read_relocs (abfd, insn_sec, NULL, NULL, FALSE);

      elf_section_data (insn_sec)->relocs = saved_relocs;

      if (internal_relocs == NULL)

        {

          *error_message = _("out of memory");

          goto cleanup;

        }

    }

  /* Create a relocation section for the property section.  */

  if (internal_relocs != NULL)

    {

      elf_section_data (prop_sec)->relocs = internal_relocs;

      prop_sec->reloc_count = reloc_count;

    }

  /* Now copy each insn table entry to the prop table entry with

     appropriate flags.  */

  for (entry = 0; entry < entry_count; ++entry)

    {

      unsigned value;

      unsigned flags = (XTENSA_PROP_INSN | XTENSA_PROP_NO_TRANSFORM

                        | XTENSA_PROP_INSN_NO_REORDER);

      value = bfd_get_32 (abfd, insn_contents + entry * 8 + 0);

      bfd_put_32 (abfd, value, prop_contents + entry * 12 + 0);

      value = bfd_get_32 (abfd, insn_contents + entry * 8 + 4);

      bfd_put_32 (abfd, value, prop_contents + entry * 12 + 4);

      bfd_put_32 (abfd, flags, prop_contents + entry * 12 + 8);

    }

  /* Now copy all of the relocations.  Change offsets for the

     instruction table section to offsets in the property table

     section.  */

  if (internal_relocs)

    {

      unsigned i;

      for (i = 0; i < reloc_count; i++)

        {

          Elf_Internal_Rela *rela;

          unsigned r_offset;

          rela = &internal_relocs[i];

          /* If this relocation is to the .xt.insn section,

             change the section number and the offset.  */

          r_offset = rela->r_offset;

          r_offset += 4 * (r_offset / 8);

          rela->r_offset = r_offset;

        }

    }

  remove_section (abfd, insn_sec);

  if (insn_contents)

    free (insn_contents);

  return TRUE;

 cleanup:

  if (prop_sec && prop_sec->owner)

    remove_section (abfd, prop_sec);

  if (insn_contents)

    free (insn_contents);

  if (internal_relocs)

    free (internal_relocs);

  return FALSE;

}

#define PROP_SEC_BASE_NAME ".xt.prop"

#define INSN_SEC_BASE_NAME ".xt.insn"

#define LINKONCE_SEC_OLD_TEXT_BASE_NAME ".gnu.linkonce.x."

static void

replace_instruction_table_sections (bfd *abfd, asection *sec)

{

  char *message = "";

  const char *insn_sec_name = NULL;

  char *prop_sec_name = NULL;

  char *owned_prop_sec_name = NULL;

  const char *sec_name;

  sec_name = bfd_get_section_name (abfd, sec);

  if (strcmp (sec_name, INSN_SEC_BASE_NAME) == 0)

    {

      insn_sec_name = INSN_SEC_BASE_NAME;

      prop_sec_name = PROP_SEC_BASE_NAME;

    }

  else if (CONST_STRNEQ (sec_name, LINKONCE_SEC_OLD_TEXT_BASE_NAME))

    {

      insn_sec_name = sec_name;

      owned_prop_sec_name = (char *) xmalloc (strlen (sec_name) + 20);

      prop_sec_name = owned_prop_sec_name;

      strcpy (prop_sec_name, ".gnu.linkonce.prop.t.");

      strcat (prop_sec_name,

              sec_name + strlen (LINKONCE_SEC_OLD_TEXT_BASE_NAME));

    }

  if (insn_sec_name != NULL)

    {

      if (! replace_insn_sec_with_prop_sec (abfd, insn_sec_name, prop_sec_name,

                                            &message))

        {

          einfo (_("%P: warning: failed to convert %s table in %B (%s); subsequent disassembly may be incomplete\n"),

                 insn_sec_name, abfd, message);

        }

    }

  if (owned_prop_sec_name)

    free (owned_prop_sec_name);

}

/* This is called after all input sections have been opened to convert

   instruction tables (.xt.insn, gnu.linkonce.x.*) tables into property

   tables (.xt.prop) before any section placement.  */

static void

elf_xtensa_after_open (void)

{

  /* First call the ELF version.  */

  gld${EMULATION_NAME}_after_open ();

  /* Now search the input files looking for instruction table sections.  */

  LANG_FOR_EACH_INPUT_STATEMENT (f)

    {

      asection *sec = f->the_bfd->sections;

      asection *next_sec;

      /* Do not use bfd_map_over_sections here since we are removing

         sections as we iterate.  */

      while (sec != NULL)

        {

          next_sec = sec->next;

          replace_instruction_table_sections (f->the_bfd, sec);

          sec = next_sec;

        }

    }

}

static bfd_boolean

xt_config_info_unpack_and_check (char *data,

                                 bfd_boolean *pmismatch,

                                 char **pmsg)

{

  char *d, *key;

  unsigned num;

  *pmismatch = FALSE;

  d = data;

  while (*d)

    {

      key = d;

      d = strchr (d, '=');

      if (! d)

        goto error;

      /* Overwrite the equal sign.  */

      *d++ = 0;

      /* Check if this is a quoted string or a number.  */

      if (*d == '"')

        {

          /* No string values are currently checked by LD;

             just skip over the quotes.  */

          d++;

          d = strchr (d, '"');

          if (! d)

            goto error;

          /* Overwrite the trailing quote.  */

          *d++ = 0;

        }

      else

        {

          if (*d == 0)

            goto error;

          num = strtoul (d, &d, 0);

          if (! strcmp (key, "ABI"))

            {

              if (num != XSHAL_ABI)

                {

                  *pmismatch = TRUE;

                  *pmsg = "ABI does not match";

                }

            }

          else if (! strcmp (key, "USE_ABSOLUTE_LITERALS"))

            {

              if (num != XSHAL_USE_ABSOLUTE_LITERALS)

                {

                  *pmismatch = TRUE;

                  *pmsg = "incompatible use of the Extended L32R option";

                }

            }

        }

      if (*d++ != '\n')

        goto error;

    }

  return TRUE;

 error:

  return FALSE;

}

#define XTINFO_NAME "Xtensa_Info"

#define XTINFO_NAMESZ 12

#define XTINFO_TYPE 1

static void

check_xtensa_info (bfd *abfd, asection *info_sec)

{

  char *data, *errmsg = "";

  bfd_boolean mismatch;

  data = xmalloc (info_sec->size);

  if (! bfd_get_section_contents (abfd, info_sec, data, 0, info_sec->size))

    einfo (_("%F%P:%B: cannot read contents of section %A\n"), abfd, info_sec);

  if (info_sec->size > 24

      && info_sec->size >= 24 + bfd_get_32 (abfd, data + 4)

      && bfd_get_32 (abfd, data + 0) == XTINFO_NAMESZ

      && bfd_get_32 (abfd, data + 8) == XTINFO_TYPE

      && strcmp (data + 12, XTINFO_NAME) == 0

      && xt_config_info_unpack_and_check (data + 12 + XTINFO_NAMESZ,

                                          &mismatch, &errmsg))

    {

      if (mismatch)

        einfo (_("%P:%B: warning: incompatible Xtensa configuration (%s)\n"),

               abfd, errmsg);

    }

  else

    einfo (_("%P:%B: warning: cannot parse .xtensa.info section\n"), abfd);

  free (data);

}

/* This is called after the sections have been attached to output

   sections, but before any sizes or addresses have been set.  */

static void

elf_xtensa_before_allocation (void)

{

  asection *info_sec, *first_info_sec;

  bfd *first_bfd;

  bfd_boolean is_big_endian = XCHAL_HAVE_BE;

  /* Check that the output endianness matches the Xtensa

     configuration.  The BFD library always includes both big and

     little endian target vectors for Xtensa, but it only supports the

     detailed instruction encode/decode operations (such as are

     required to process relocations) for the selected Xtensa

     configuration.  */

  if (is_big_endian

      && link_info.output_bfd->xvec->byteorder == BFD_ENDIAN_LITTLE)

    {

      einfo (_("%F%P: little endian output does not match "

               "Xtensa configuration\n"));

    }

  if (!is_big_endian

      && link_info.output_bfd->xvec->byteorder == BFD_ENDIAN_BIG)

    {

      einfo (_("%F%P: big endian output does not match "

               "Xtensa configuration\n"));

    }

  /* Keep track of the first input .xtensa.info section, and as a fallback,

     the first input bfd where a .xtensa.info section could be created.

     After the input .xtensa.info has been checked, the contents of the

     first one will be replaced with the output .xtensa.info table.  */

  first_info_sec = 0;

  first_bfd = 0;

  LANG_FOR_EACH_INPUT_STATEMENT (f)

    {

      /* Check that the endianness for each input file matches the output.

         The merge_private_bfd_data hook has already reported any mismatches

         as errors, but those errors are not fatal.  At this point, we

         cannot go any further if there are any mismatches.  */

      if ((is_big_endian && f->the_bfd->xvec->byteorder == BFD_ENDIAN_LITTLE)

          || (!is_big_endian && f->the_bfd->xvec->byteorder == BFD_ENDIAN_BIG))

        einfo (_("%F%P: cross-endian linking for %B not supported\n"),

               f->the_bfd);

      if (! first_bfd)

        first_bfd = f->the_bfd;

      info_sec = bfd_get_section_by_name (f->the_bfd, ".xtensa.info");

      if (! info_sec)

        continue;

      if (! first_info_sec)

        first_info_sec = info_sec;

      /* Unpack the .xtensa.info section and check it against the current

         Xtensa configuration.  */

      check_xtensa_info (f->the_bfd, info_sec);

      /* Do not include this copy of .xtensa.info in the output.  */

      info_sec->size = 0;

      info_sec->flags |= SEC_EXCLUDE;

    }

  /* Reuse the first .xtensa.info input section to hold the output

     .xtensa.info; or, if none were found, create a new section in the

     first input bfd (assuming there is one).  */

  info_sec = first_info_sec;

  if (! info_sec && first_bfd)

    {

      info_sec = bfd_make_section_with_flags (first_bfd, ".xtensa.info",

                                              SEC_HAS_CONTENTS | SEC_READONLY);

      if (! info_sec)

        einfo (_("%F%P: failed to create .xtensa.info section\n"));

    }

  if (info_sec)

    {

      int xtensa_info_size;

      char *data;

      info_sec->flags &= ~SEC_EXCLUDE;

      info_sec->flags |= SEC_IN_MEMORY;

      data = xmalloc (100);

      sprintf (data, "USE_ABSOLUTE_LITERALS=%d\nABI=%d\n",

               XSHAL_USE_ABSOLUTE_LITERALS, XSHAL_ABI);

      xtensa_info_size = strlen (data) + 1;

      /* Add enough null terminators to pad to a word boundary.  */

      do

        data[xtensa_info_size++] = 0;

      while ((xtensa_info_size & 3) != 0);

      info_sec->size = 12 + XTINFO_NAMESZ + xtensa_info_size;

      info_sec->contents = xmalloc (info_sec->size);

      bfd_put_32 (info_sec->owner, XTINFO_NAMESZ, info_sec->contents + 0);

      bfd_put_32 (info_sec->owner, xtensa_info_size, info_sec->contents + 4);

      bfd_put_32 (info_sec->owner, XTINFO_TYPE, info_sec->contents + 8);

      memcpy (info_sec->contents + 12, XTINFO_NAME, XTINFO_NAMESZ);

      memcpy (info_sec->contents + 12 + XTINFO_NAMESZ, data, xtensa_info_size);

      free (data);

    }

  /* Enable relaxation by default if the "--no-relax" option was not

     specified.  This is done here instead of in the before_parse hook

     because there is a check in main() to prohibit use of --relax and

     -r together and that combination should be allowed for Xtensa.  */

  if (RELAXATION_DISABLED_BY_DEFAULT)

    ENABLE_RELAXATION;

  xtensa_strip_inconsistent_linkonce_sections (stat_ptr);

  gld${EMULATION_NAME}_before_allocation ();

  xtensa_wild_group_interleave (stat_ptr->head);

  if (RELAXATION_ENABLED)

    xtensa_colocate_output_literals (stat_ptr->head);

  /* TBD: We need to force the page alignments to here and only do

     them as needed for the entire output section.  Finally, if this

     is a relocatable link then we need to add alignment notes so

     that the literals can be separated later.  */

}

typedef struct wildcard_list section_name_list;

typedef struct reloc_deps_e_t reloc_deps_e;

typedef struct reloc_deps_section_t reloc_deps_section;

typedef struct reloc_deps_graph_t reloc_deps_graph;

struct reloc_deps_e_t

{

  asection *src; /* Contains l32rs.  */

  asection *tgt; /* Contains literals.  */

  reloc_deps_e *next;

};

/* Place these in the userdata field.  */

struct reloc_deps_section_t

{

  reloc_deps_e *preds;

  reloc_deps_e *succs;

  bfd_boolean is_only_literal;

};

struct reloc_deps_graph_t

{

  size_t count;

  size_t size;

  asection **sections;

};

static void xtensa_layout_wild

  (const reloc_deps_graph *, lang_wild_statement_type *);

typedef void (*deps_callback_t) (asection *, /* src_sec */

                                 bfd_vma,    /* src_offset */

                                 asection *, /* target_sec */

                                 bfd_vma,    /* target_offset */

                                 void *);    /* closure */

extern bfd_boolean xtensa_callback_required_dependence

  (bfd *, asection *, struct bfd_link_info *, deps_callback_t, void *);

static void xtensa_ldlang_clear_addresses (lang_statement_union_type *);

static bfd_boolean ld_local_file_relocations_fit

  (lang_statement_union_type *, const reloc_deps_graph *);

static bfd_vma ld_assign_relative_paged_dot

  (bfd_vma, lang_statement_union_type *, const reloc_deps_graph *,

   bfd_boolean);

static bfd_vma ld_xtensa_insert_page_offsets

  (bfd_vma, lang_statement_union_type *, reloc_deps_graph *, bfd_boolean);

#if EXTRA_VALIDATION

static size_t ld_count_children (lang_statement_union_type *);

#endif

extern lang_statement_list_type constructor_list;

static reloc_deps_section *

xtensa_get_section_deps (const reloc_deps_graph *deps ATTRIBUTE_UNUSED,

                         asection *sec)

{

  /* We have a separate function for this so that

     we could in the future keep a completely independent

     structure that maps a section to its dependence edges.

     For now, we place these in the sec->userdata field.  */

  reloc_deps_section *sec_deps = sec->userdata;

  return sec_deps;

}

static void

xtensa_set_section_deps (const reloc_deps_graph *deps ATTRIBUTE_UNUSED,

                         asection *sec,

                         reloc_deps_section *deps_section)

{

  sec->userdata = deps_section;

}

/* This is used to keep a list of all of the sections participating in

   the graph so we can clean them up quickly.  */

static void

xtensa_append_section_deps (reloc_deps_graph *deps, asection *sec)

{

  if (deps->size <= deps->count)

    {

      asection **new_sections;

      size_t i;

      size_t new_size;

      new_size = deps->size * 2;

      if (new_size == 0)

        new_size = 20;

      new_sections = xmalloc (sizeof (asection *) * new_size);

      memset (new_sections, 0, sizeof (asection *) * new_size);

      for (i = 0; i < deps->count; i++)

        {

          new_sections[i] = deps->sections[i];

        }

      if (deps->sections != NULL)

        free (deps->sections);

      deps->sections = new_sections;

      deps->size = new_size;

    }

  deps->sections[deps->count] = sec;

  deps->count++;

}

static void

free_reloc_deps_graph (reloc_deps_graph *deps)

{

  size_t i;

  for (i = 0; i < deps->count; i++)

    {

      asection *sec = deps->sections[i];

      reloc_deps_section *sec_deps;

      sec_deps = xtensa_get_section_deps (deps, sec);

      if (sec_deps)

        {

          reloc_deps_e *next;

          while (sec_deps->succs != NULL)

            {

              next = sec_deps->succs->next;

              free (sec_deps->succs);

              sec_deps->succs = next;

            }

          while (sec_deps->preds != NULL)

            {

              next = sec_deps->preds->next;

              free (sec_deps->preds);

              sec_deps->preds = next;

            }

          free (sec_deps);

        }

      xtensa_set_section_deps (deps, sec, NULL);

    }

  if (deps->sections)

    free (deps->sections);

  free (deps);

}

static bfd_boolean

section_is_source (const reloc_deps_graph *deps ATTRIBUTE_UNUSED,

                   lang_statement_union_type *s)

{

  asection *sec;

  const reloc_deps_section *sec_deps;

  if (s->header.type != lang_input_section_enum)

    return FALSE;

  sec = s->input_section.section;

  sec_deps = xtensa_get_section_deps (deps, sec);

  return sec_deps && sec_deps->succs != NULL;

}

static bfd_boolean

section_is_target (const reloc_deps_graph *deps ATTRIBUTE_UNUSED,

                   lang_statement_union_type *s)

{

  asection *sec;

  const reloc_deps_section *sec_deps;

  if (s->header.type != lang_input_section_enum)

    return FALSE;

  sec = s->input_section.section;

  sec_deps = xtensa_get_section_deps (deps, sec);

  return sec_deps && sec_deps->preds != NULL;

}

static bfd_boolean

section_is_source_or_target (const reloc_deps_graph *deps ATTRIBUTE_UNUSED,

                             lang_statement_union_type *s)

{

  return (section_is_source (deps, s)

          || section_is_target (deps, s));

}

typedef struct xtensa_ld_iter_stack_t xtensa_ld_iter_stack;

typedef struct xtensa_ld_iter_t xtensa_ld_iter;

struct xtensa_ld_iter_t

{

  lang_statement_union_type *parent;    /* Parent of the list.  */

  lang_statement_list_type *l;          /* List that holds it.  */

  lang_statement_union_type **loc;      /* Place in the list.  */

};

struct xtensa_ld_iter_stack_t

{

  xtensa_ld_iter iterloc;               /* List that hold it.  */

  xtensa_ld_iter_stack *next;           /* Next in the stack.  */

  xtensa_ld_iter_stack *prev;           /* Back pointer for stack.  */

};

static void

ld_xtensa_move_section_after (xtensa_ld_iter *to, xtensa_ld_iter *current)

{

  lang_statement_union_type *to_next;

  lang_statement_union_type *current_next;

  lang_statement_union_type **e;

#if EXTRA_VALIDATION

  size_t old_to_count, new_to_count;

  size_t old_current_count, new_current_count;

#endif

  if (to == current)

    return;

#if EXTRA_VALIDATION

  old_to_count = ld_count_children (to->parent);

  old_current_count = ld_count_children (current->parent);

#endif

  to_next = *(to->loc);

  current_next = (*current->loc)->header.next;

  *(to->loc) = *(current->loc);

  *(current->loc) = current_next;

  (*(to->loc))->header.next = to_next;

  /* reset "to" list tail */

  for (e = &to->l->head; *e != NULL; e = &(*e)->header.next)

    ;

  to->l->tail = e;

  /* reset "current" list tail */

  for (e = ¤t->l->head; *e != NULL; e = &(*e)->header.next)

    ;

  current->l->tail = e;

#if EXTRA_VALIDATION

  new_to_count = ld_count_children (to->parent);

  new_current_count = ld_count_children (current->parent);

  ASSERT ((old_to_count + old_current_count)

          == (new_to_count + new_current_count));

#endif

}

/* Can only be called with lang_statements that have lists.  Returns

   FALSE if the list is empty.  */

static bfd_boolean

iter_stack_empty (xtensa_ld_iter_stack **stack_p)

{

  return *stack_p == NULL;

}

static bfd_boolean

iter_stack_push (xtensa_ld_iter_stack **stack_p,

                 lang_statement_union_type *parent)

{

  xtensa_ld_iter_stack *stack;

  lang_statement_list_type *l = NULL;

  switch (parent->header.type)

    {

    case lang_output_section_statement_enum:

      l = &parent->output_section_statement.children;

      break;

    case lang_wild_statement_enum:

      l = &parent->wild_statement.children;

      break;

    case lang_group_statement_enum:

      l = &parent->group_statement.children;

      break;

    default:

      ASSERT (0);

      return FALSE;

    }

  /* Empty. do not push.  */

  if (l->tail == &l->head)

    return FALSE;

  stack = xmalloc (sizeof (xtensa_ld_iter_stack));

  memset (stack, 0, sizeof (xtensa_ld_iter_stack));

  stack->iterloc.parent = parent;

  stack->iterloc.l = l;

  stack->iterloc.loc = &l->head;

  stack->next = *stack_p;

  stack->prev = NULL;

  if (*stack_p != NULL)

    (*stack_p)->prev = stack;

  *stack_p = stack;

  return TRUE;

}

static void

iter_stack_pop (xtensa_ld_iter_stack **stack_p)

{

  xtensa_ld_iter_stack *stack;

  stack = *stack_p;

  if (stack == NULL)

    {

      ASSERT (stack != NULL);

      return;

    }

  if (stack->next != NULL)

    stack->next->prev = NULL;

  *stack_p = stack->next;

  free (stack);

}

/* This MUST be called if, during iteration, the user changes the

   underlying structure.  It will check for a NULL current and advance

   accordingly.  */

static void

iter_stack_update (xtensa_ld_iter_stack **stack_p)

{

  if (!iter_stack_empty (stack_p)

      && (*(*stack_p)->iterloc.loc) == NULL)

    {

      iter_stack_pop (stack_p);

      while (!iter_stack_empty (stack_p)

             && ((*(*stack_p)->iterloc.loc)->header.next == NULL))

        {

          iter_stack_pop (stack_p);

        }

      if (!iter_stack_empty (stack_p))

        (*stack_p)->iterloc.loc = &(*(*stack_p)->iterloc.loc)->header.next;

    }

}

static void

iter_stack_next (xtensa_ld_iter_stack **stack_p)

{

  xtensa_ld_iter_stack *stack;

  lang_statement_union_type *current;

  stack = *stack_p;

  current = *stack->iterloc.loc;

  /* If we are on the first element.  */

  if (current != NULL)

    {

      switch (current->header.type)

        {

        case lang_output_section_statement_enum:

        case lang_wild_statement_enum:

        case lang_group_statement_enum:

          /* If the list if not empty, we are done.  */

          if (iter_stack_push (stack_p, *stack->iterloc.loc))

            return;

          /* Otherwise increment the pointer as normal.  */

          break;

        default:

          break;

        }

    }

  while (!iter_stack_empty (stack_p)

         && ((*(*stack_p)->iterloc.loc)->header.next == NULL))

    {

      iter_stack_pop (stack_p);

    }

  if (!iter_stack_empty (stack_p))

    (*stack_p)->iterloc.loc = &(*(*stack_p)->iterloc.loc)->header.next;

}

static lang_statement_union_type *

iter_stack_current (xtensa_ld_iter_stack **stack_p)

{

  return *((*stack_p)->iterloc.loc);

}

/* The iter stack is a preorder.  */

static void

iter_stack_create (xtensa_ld_iter_stack **stack_p,

                   lang_statement_union_type *parent)