text: /* SEC_MERGE support.
     Copyright (C) 2001-2021 Free Software Foundation, Inc.
     Written by Jakub Jelinek <jakub@redhat.com>.
  
     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., 51 Franklin Street - Fifth Floor, Boston,
     MA 02110-1301, USA.  */
  
  
  /* This file contains support for merging duplicate entities within sections,
     as used in ELF SHF_MERGE.  */
  
  #include "sysdep.h"
  #include <limits.h>
  #include "bfd.h"
  #include "elf-bfd.h"
  #include "libbfd.h"
  #include "hashtab.h"
  #include "libiberty.h"
  
  struct sec_merge_sec_info;
  
  /* An entry in the section merge hash table.  */
  
  struct sec_merge_hash_entry
  {
    struct bfd_hash_entry root;
    /* Length of this entry.  This includes the zero terminator.  */
    unsigned int len;
    /* Start of this string needs to be aligned to
       alignment octets (not 1 << align).  */
    unsigned int alignment;
    union
    {
      /* Index within the merged section.  */
      bfd_size_type index;
      /* Entry this is a suffix of (if alignment is 0).  */
      struct sec_merge_hash_entry *suffix;
    } u;
    /* Which section is it in.  */
    struct sec_merge_sec_info *secinfo;
    /* Next entity in the hash table.  */
    struct sec_merge_hash_entry *next;
  };
  
  /* The section merge hash table.  */
  
  struct sec_merge_hash
  {
    struct bfd_hash_table table;
    /* Next available index.  */
    bfd_size_type size;
    /* First entity in the SEC_MERGE sections of this type.  */
    struct sec_merge_hash_entry *first;
    /* Last entity in the SEC_MERGE sections of this type.  */
    struct sec_merge_hash_entry *last;
    /* Entity size.  */
    unsigned int entsize;
    /* Are entries fixed size or zero terminated strings?  */
    bool strings;
  };
  
  struct sec_merge_info
  {
    /* Chain of sec_merge_infos.  */
    struct sec_merge_info *next;
    /* Chain of sec_merge_sec_infos.  */
    struct sec_merge_sec_info *chain;
    /* A hash table used to hold section content.  */
    struct sec_merge_hash *htab;
  };
  
  struct sec_merge_sec_info
  {
    /* Chain of sec_merge_sec_infos.  */
    struct sec_merge_sec_info *next;
    /* The corresponding section.  */
    asection *sec;
    /* Pointer to merge_info pointing to us.  */
    void **psecinfo;
    /* A hash table used to hold section content.  */
    struct sec_merge_hash *htab;
    /* First string in this section.  */
    struct sec_merge_hash_entry *first_str;
    /* Original section content.  */
    unsigned char contents[1];
  };
  
  
  /* Routine to create an entry in a section merge hashtab.  */
  
  static struct bfd_hash_entry *
  sec_merge_hash_newfunc (struct bfd_hash_entry *entry,
  			struct bfd_hash_table *table, const char *string)
  {
    /* Allocate the structure if it has not already been allocated by a
       subclass.  */
    if (entry == NULL)
      entry = (struct bfd_hash_entry *)
  	bfd_hash_allocate (table, sizeof (struct sec_merge_hash_entry));
    if (entry == NULL)
      return NULL;
  
    /* Call the allocation method of the superclass.  */
    entry = bfd_hash_newfunc (entry, table, string);
  
    if (entry != NULL)
      {
        /* Initialize the local fields.  */
        struct sec_merge_hash_entry *ret = (struct sec_merge_hash_entry *) entry;
  
        ret->u.suffix = NULL;
        ret->alignment = 0;
        ret->secinfo = NULL;
        ret->next = NULL;
      }
  
    return entry;
  }
  
  /* Look up an entry in a section merge hash table.  */
  
  static struct sec_merge_hash_entry *
  sec_merge_hash_lookup (struct sec_merge_hash *table, const char *string,
  		       unsigned int alignment, bool create)
  {
    const unsigned char *s;
    unsigned long hash;
    unsigned int c;
    struct sec_merge_hash_entry *hashp;
    unsigned int len, i;
    unsigned int _index;
  
    hash = 0;
    len = 0;
    s = (const unsigned char *) string;
    if (table->strings)
      {
        if (table->entsize == 1)
  	{
  	  while ((c = *s++) != '\0')
  	    {
  	      hash += c + (c << 17);
  	      hash ^= hash >> 2;
  	      ++len;
  	    }
  	  hash += len + (len << 17);
  	}
        else
  	{
  	  for (;;)
  	    {
  	      for (i = 0; i < table->entsize; ++i)
  		if (s[i] != '\0')
  		  break;
  	      if (i == table->entsize)
  		break;
  	      for (i = 0; i < table->entsize; ++i)
  		{
  		  c = *s++;
  		  hash += c + (c << 17);
  		  hash ^= hash >> 2;
  		}
  	      ++len;
  	    }
  	  hash += len + (len << 17);
  	  len *= table->entsize;
  	}
        hash ^= hash >> 2;
        len += table->entsize;
      }
    else
      {
        for (i = 0; i < table->entsize; ++i)
  	{
  	  c = *s++;
  	  hash += c + (c << 17);
  	  hash ^= hash >> 2;
  	}
        len = table->entsize;
      }
  
    _index = hash % table->table.size;
    for (hashp = (struct sec_merge_hash_entry *) table->table.table[_index];
         hashp != NULL;
         hashp = (struct sec_merge_hash_entry *) hashp->root.next)
      {
        if (hashp->root.hash == hash
  	  && len == hashp->len
  	  && memcmp (hashp->root.string, string, len) == 0)
  	{
  	  /* If the string we found does not have at least the required
  	     alignment, we need to insert another copy.  */
  	  if (hashp->alignment < alignment)
  	    {
  	      if (create)
  		{
  		  /*  Mark the less aligned copy as deleted.  */
  		  hashp->len = 0;
  		  hashp->alignment = 0;
  		}
  	      break;
  	    }
  	  return hashp;
  	}
      }
  
    if (! create)
      return NULL;
  
    hashp = ((struct sec_merge_hash_entry *)
  	   bfd_hash_insert (&table->table, string, hash));
    if (hashp == NULL)
      return NULL;
    hashp->len = len;
    hashp->alignment = alignment;
    return hashp;
  }
  
  /* Create a new hash table.  */
  
  static struct sec_merge_hash *
  sec_merge_init (unsigned int entsize, bool strings)
  {
    struct sec_merge_hash *table;
  
    table = (struct sec_merge_hash *) bfd_malloc (sizeof (struct sec_merge_hash));
    if (table == NULL)
      return NULL;
  
    if (! bfd_hash_table_init_n (&table->table, sec_merge_hash_newfunc,
  			       sizeof (struct sec_merge_hash_entry), 16699))
      {
        free (table);
        return NULL;
      }
  
    table->size = 0;
    table->first = NULL;
    table->last = NULL;
    table->entsize = entsize;
    table->strings = strings;
  
    return table;
  }
  
  /* Get the index of an entity in a hash table, adding it if it is not
     already present.  */
  
  static struct sec_merge_hash_entry *
  sec_merge_add (struct sec_merge_hash *tab, const char *str,
  	       unsigned int alignment, struct sec_merge_sec_info *secinfo)
  {
    struct sec_merge_hash_entry *entry;
  
    entry = sec_merge_hash_lookup (tab, str, alignment, true);
    if (entry == NULL)
      return NULL;
  
    if (entry->secinfo == NULL)
      {
        tab->size++;
        entry->secinfo = secinfo;
        if (tab->first == NULL)
  	tab->first = entry;
        else
  	tab->last->next = entry;
        tab->last = entry;
      }
  
    return entry;
  }
  
  static bool
  sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry,
  		unsigned char *contents, file_ptr offset)
  {
    struct sec_merge_sec_info *secinfo = entry->secinfo;
    asection *sec = secinfo->sec;
    char *pad = NULL;
    bfd_size_type off = 0;
    unsigned int opb = bfd_octets_per_byte (abfd, sec);
    int alignment_power = sec->output_section->alignment_power * opb;
    bfd_size_type pad_len;  /* Octets.  */
  
    /* FIXME: If alignment_power is 0 then really we should scan the
       entry list for the largest required alignment and use that.  */
    pad_len = alignment_power ? ((bfd_size_type) 1 << alignment_power) : 16;
  
    pad = (char *) bfd_zmalloc (pad_len);
    if (pad == NULL)
      return false;
  
    for (; entry != NULL && entry->secinfo == secinfo; entry = entry->next)
      {
        const char *str;
        bfd_size_type len;
  
        len = -off & (entry->alignment - 1);
        if (len != 0)
  	{
  	  BFD_ASSERT (len <= pad_len);
  	  if (contents)
  	    {
  	      memcpy (contents + offset, pad, len);
  	      offset += len;
  	    }
  	  else if (bfd_bwrite (pad, len, abfd) != len)
  	    goto err;
  	  off += len;
  	}
  
        str = entry->root.string;
        len = entry->len;
  
        if (contents)
  	{
  	  memcpy (contents + offset, str, len);
  	  offset += len;
  	}
        else if (bfd_bwrite (str, len, abfd) != len)
  	goto err;
  
        off += len;
      }
  
    /* Trailing alignment needed?  */
    off = sec->size - off;
    if (off != 0)
      {
        BFD_ASSERT (off <= pad_len);
        if (contents)
  	memcpy (contents + offset, pad, off);
        else if (bfd_bwrite (pad, off, abfd) != off)
  	goto err;
      }
  
    free (pad);
    return true;
  
   err:
    free (pad);
    return false;
  }
  
  /* Register a SEC_MERGE section as a candidate for merging.
     This function is called for all non-dynamic SEC_MERGE input sections.  */
  
  bool
  _bfd_add_merge_section (bfd *abfd, void **psinfo, asection *sec,
  			void **psecinfo)
  {
    struct sec_merge_info *sinfo;
    struct sec_merge_sec_info *secinfo;
    unsigned int alignment_power;  /* Octets.  */
    unsigned int align;            /* Octets.  */
    bfd_size_type amt;
    bfd_byte *contents;
    unsigned int opb = bfd_octets_per_byte (abfd, sec);
  
    if ((abfd->flags & DYNAMIC) != 0
        || (sec->flags & SEC_MERGE) == 0)
      abort ();
  
    if (sec->size == 0
        || (sec->flags & SEC_EXCLUDE) != 0
        || sec->entsize == 0)
      return true;
  
    if (sec->size % sec->entsize != 0)
      return true;
  
    if ((sec->flags & SEC_RELOC) != 0)
      {
        /* We aren't prepared to handle relocations in merged sections.  */
        return true;
      }
  
  #ifndef CHAR_BIT
  #define CHAR_BIT 8
  #endif
    alignment_power = sec->alignment_power * opb;
    if (alignment_power >= sizeof (align) * CHAR_BIT)
      return true;
  
    align = 1u << alignment_power;
    if ((sec->entsize < align
         && ((sec->entsize & (sec->entsize - 1))
  	   || !(sec->flags & SEC_STRINGS)))
        || (sec->entsize > align
  	  && (sec->entsize & (align - 1))))
      {
        /* Sanity check.  If string character size is smaller than
  	 alignment, then we require character size to be a power
  	 of 2, otherwise character size must be integer multiple
  	 of alignment.  For non-string constants, alignment must
  	 be smaller than or equal to entity size and entity size
  	 must be integer multiple of alignment.  */
        return true;
      }
  
    for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next)
      if ((secinfo = sinfo->chain)
  	&& ! ((secinfo->sec->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS))
  	&& secinfo->sec->entsize == sec->entsize
  	&& secinfo->sec->alignment_power == sec->alignment_power
  	&& secinfo->sec->output_section == sec->output_section)
        break;
  
    if (sinfo == NULL)
      {
        /* Initialize the information we need to keep track of.  */
        sinfo = (struct sec_merge_info *)
  	  bfd_alloc (abfd, sizeof (struct sec_merge_info));
        if (sinfo == NULL)
  	goto error_return;
        sinfo->next = (struct sec_merge_info *) *psinfo;
        sinfo->chain = NULL;
        *psinfo = sinfo;
        sinfo->htab = sec_merge_init (sec->entsize, (sec->flags & SEC_STRINGS));
        if (sinfo->htab == NULL)
  	goto error_return;
      }
  
    /* Read the section from abfd.  */
  
    amt = sizeof (struct sec_merge_sec_info) - 1 + sec->size;
    if (sec->flags & SEC_STRINGS)
      /* Some versions of gcc may emit a string without a zero terminator.
         See http://gcc.gnu.org/ml/gcc-patches/2006-06/msg01004.html
         Allocate space for an extra zero.  */
      amt += sec->entsize;
    *psecinfo = bfd_alloc (abfd, amt);
    if (*psecinfo == NULL)
      goto error_return;
  
    secinfo = (struct sec_merge_sec_info *) *psecinfo;
    if (sinfo->chain)
      {
        secinfo->next = sinfo->chain->next;
        sinfo->chain->next = secinfo;
      }
    else
      secinfo->next = secinfo;
    sinfo->chain = secinfo;
    secinfo->sec = sec;
    secinfo->psecinfo = psecinfo;
    secinfo->htab = sinfo->htab;
    secinfo->first_str = NULL;
  
    sec->rawsize = sec->size;
    if (sec->flags & SEC_STRINGS)
      memset (secinfo->contents + sec->size, 0, sec->entsize);
    contents = secinfo->contents;
    if (! bfd_get_full_section_contents (sec->owner, sec, &contents))
      goto error_return;
  
    return true;
  
   error_return:
    *psecinfo = NULL;
    return false;
  }
  
  /* Record one section into the hash table.  */
  static bool
  record_section (struct sec_merge_info *sinfo,
  		struct sec_merge_sec_info *secinfo)
  {
    asection *sec = secinfo->sec;
    struct sec_merge_hash_entry *entry;
    bool nul;
    unsigned char *p, *end;
    bfd_vma mask, eltalign;
    unsigned int align, i;
  
    align = sec->alignment_power;
    end = secinfo->contents + sec->size;
    nul = false;
    mask = ((bfd_vma) 1 << align) - 1;
    if (sec->flags & SEC_STRINGS)
      {
        for (p = secinfo->contents; p < end; )
  	{
  	  eltalign = p - secinfo->contents;
  	  eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1;
  	  if (!eltalign || eltalign > mask)
  	    eltalign = mask + 1;
  	  entry = sec_merge_add (sinfo->htab, (char *) p, (unsigned) eltalign,
  				 secinfo);
  	  if (! entry)
  	    goto error_return;
  	  p += entry->len;
  	  if (sec->entsize == 1)
  	    {
  	      while (p < end && *p == 0)
  		{
  		  if (!nul && !((p - secinfo->contents) & mask))
  		    {
  		      nul = true;
  		      entry = sec_merge_add (sinfo->htab, "",
  					     (unsigned) mask + 1, secinfo);
  		      if (! entry)
  			goto error_return;
  		    }
  		  p++;
  		}
  	    }
  	  else
  	    {
  	      while (p < end)
  		{
  		  for (i = 0; i < sec->entsize; i++)
  		    if (p[i] != '\0')
  		      break;
  		  if (i != sec->entsize)
  		    break;
  		  if (!nul && !((p - secinfo->contents) & mask))
  		    {
  		      nul = true;
  		      entry = sec_merge_add (sinfo->htab, (char *) p,
  					     (unsigned) mask + 1, secinfo);
  		      if (! entry)
  			goto error_return;
  		    }
  		  p += sec->entsize;
  		}
  	    }
  	}
      }
    else
      {
        for (p = secinfo->contents; p < end; p += sec->entsize)
  	{
  	  entry = sec_merge_add (sinfo->htab, (char *) p, 1, secinfo);
  	  if (! entry)
  	    goto error_return;
  	}
      }
  
    return true;
  
   error_return:
    for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
      *secinfo->psecinfo = NULL;
    return false;
  }
  
  /* qsort comparison function.  Won't ever return zero as all entries
     differ, so there is no issue with qsort stability here.  */
  
  static int
  strrevcmp (const void *a, const void *b)
  {
    struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
    struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
    unsigned int lenA = A->len;
    unsigned int lenB = B->len;
    const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
    const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
    int l = lenA < lenB ? lenA : lenB;
  
    while (l)
      {
        if (*s != *t)
  	return (int) *s - (int) *t;
        s--;
        t--;
        l--;
      }
    return lenA - lenB;
  }
  
  /* Like strrevcmp, but for the case where all strings have the same
     alignment > entsize.  */
  
  static int
  strrevcmp_align (const void *a, const void *b)
  {
    struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a;
    struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b;
    unsigned int lenA = A->len;
    unsigned int lenB = B->len;
    const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1;
    const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1;
    int l = lenA < lenB ? lenA : lenB;
    int tail_align = (lenA & (A->alignment - 1)) - (lenB & (A->alignment - 1));
  
    if (tail_align != 0)
      return tail_align;
  
    while (l)
      {
        if (*s != *t)
  	return (int) *s - (int) *t;
        s--;
        t--;
        l--;
      }
    return lenA - lenB;
  }
  
  static inline int
  is_suffix (const struct sec_merge_hash_entry *A,
  	   const struct sec_merge_hash_entry *B)
  {
    if (A->len <= B->len)
      /* B cannot be a suffix of A unless A is equal to B, which is guaranteed
         not to be equal by the hash table.  */
      return 0;
  
    return memcmp (A->root.string + (A->len - B->len),
  		 B->root.string, B->len) == 0;
  }
  
  /* This is a helper function for _bfd_merge_sections.  It attempts to
     merge strings matching suffixes of longer strings.  */
  static struct sec_merge_sec_info *
  merge_strings (struct sec_merge_info *sinfo)
  {
    struct sec_merge_hash_entry **array, **a, *e;
    struct sec_merge_sec_info *secinfo;
    bfd_size_type size, amt;
    unsigned int alignment = 0;
  
    /* Now sort the strings */
    amt = sinfo->htab->size * sizeof (struct sec_merge_hash_entry *);
    array = (struct sec_merge_hash_entry **) bfd_malloc (amt);
    if (array == NULL)
      return NULL;
  
    for (e = sinfo->htab->first, a = array; e; e = e->next)
      if (e->alignment)
        {
  	*a++ = e;
  	/* Adjust the length to not include the zero terminator.  */
  	e->len -= sinfo->htab->entsize;
  	if (alignment != e->alignment)
  	  {
  	    if (alignment == 0)
  	      alignment = e->alignment;
  	    else
  	      alignment = (unsigned) -1;
  	  }
        }
  
    sinfo->htab->size = a - array;
    if (sinfo->htab->size != 0)
      {
        qsort (array, (size_t) sinfo->htab->size,
  	     sizeof (struct sec_merge_hash_entry *),
  	     (alignment != (unsigned) -1 && alignment > sinfo->htab->entsize
  	      ? strrevcmp_align : strrevcmp));
  
        /* Loop over the sorted array and merge suffixes */
        e = *--a;
        e->len += sinfo->htab->entsize;
        while (--a >= array)
  	{
  	  struct sec_merge_hash_entry *cmp = *a;
  
  	  cmp->len += sinfo->htab->entsize;
  	  if (e->alignment >= cmp->alignment
  	      && !((e->len - cmp->len) & (cmp->alignment - 1))
  	      && is_suffix (e, cmp))
  	    {
  	      cmp->u.suffix = e;
  	      cmp->alignment = 0;
  	    }
  	  else
  	    e = cmp;
  	}
      }
  
    free (array);
  
    /* Now assign positions to the strings we want to keep.  */
    size = 0;
    secinfo = sinfo->htab->first->secinfo;
    for (e = sinfo->htab->first; e; e = e->next)
      {
        if (e->secinfo != secinfo)
  	{
  	  secinfo->sec->size = size;
  	  secinfo = e->secinfo;
  	}
        if (e->alignment)
  	{
  	  if (e->secinfo->first_str == NULL)
  	    {
  	      e->secinfo->first_str = e;
  	      size = 0;
  	    }
  	  size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
  	  e->u.index = size;
  	  size += e->len;
  	}
      }
    secinfo->sec->size = size;
  
    /* And now adjust the rest, removing them from the chain (but not hashtable)
       at the same time.  */
    for (a = &sinfo->htab->first, e = *a; e; e = e->next)
      if (e->alignment)
        a = &e->next;
      else
        {
  	*a = e->next;
  	if (e->len)
  	  {
  	    e->secinfo = e->u.suffix->secinfo;
  	    e->alignment = e->u.suffix->alignment;
  	    e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len);
  	  }
        }
    return secinfo;
  }
  
  /* This function is called once after all SEC_MERGE sections are registered
     with _bfd_merge_section.  */
  
  bool
  _bfd_merge_sections (bfd *abfd,
  		     struct bfd_link_info *info ATTRIBUTE_UNUSED,
  		     void *xsinfo,
  		     void (*remove_hook) (bfd *, asection *))
  {
    struct sec_merge_info *sinfo;
  
    for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
      {
        struct sec_merge_sec_info *secinfo;
        bfd_size_type align;  /* Bytes.  */
  
        if (! sinfo->chain)
  	continue;
  
        /* Move sinfo->chain to head of the chain, terminate it.  */
        secinfo = sinfo->chain;
        sinfo->chain = secinfo->next;
        secinfo->next = NULL;
  
        /* Record the sections into the hash table.  */
        align = 1;
        for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
  	if (secinfo->sec->flags & SEC_EXCLUDE)
  	  {
  	    *secinfo->psecinfo = NULL;
  	    if (remove_hook)
  	      (*remove_hook) (abfd, secinfo->sec);
  	  }
  	else
  	  {
  	    if (!record_section (sinfo, secinfo))
  	      return false;
  	    if (align)
  	      {
  		unsigned int opb = bfd_octets_per_byte (abfd, secinfo->sec);
  
  		align = (bfd_size_type) 1 << secinfo->sec->alignment_power;
  		if (((secinfo->sec->size / opb) & (align - 1)) != 0)
  		  align = 0;
  	      }
  	  }
  
        if (sinfo->htab->first == NULL)
  	continue;
  
        if (sinfo->htab->strings)
  	{
  	  secinfo = merge_strings (sinfo);
  	  if (!secinfo)
  	    return false;
  	}
        else
  	{
  	  struct sec_merge_hash_entry *e;
  	  bfd_size_type size = 0;  /* Octets.  */
  
  	  /* Things are much simpler for non-strings.
  	     Just assign them slots in the section.  */
  	  secinfo = NULL;
  	  for (e = sinfo->htab->first; e; e = e->next)
  	    {
  	      if (e->secinfo->first_str == NULL)
  		{
  		  if (secinfo)
  		    secinfo->sec->size = size;
  		  e->secinfo->first_str = e;
  		  size = 0;
  		}
  	      size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1);
  	      e->u.index = size;
  	      size += e->len;
  	      secinfo = e->secinfo;
  	    }
  	  secinfo->sec->size = size;
  	}
  
        /* If the input sections were padded according to their alignments,
  	 then pad the output too.  */
        if (align)
  	secinfo->sec->size = (secinfo->sec->size + align - 1) & -align;
  
        /* Finally remove all input sections which have not made it into
  	 the hash table at all.  */
        for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next)
  	if (secinfo->first_str == NULL)
  	  secinfo->sec->flags |= SEC_EXCLUDE | SEC_KEEP;
      }
  
    return true;
  }
  
  /* Write out the merged section.  */
  
  bool
  _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
  {
    struct sec_merge_sec_info *secinfo;
    file_ptr pos;
    unsigned char *contents;
    Elf_Internal_Shdr *hdr;
  
    secinfo = (struct sec_merge_sec_info *) psecinfo;
  
    if (!secinfo)
      return false;
  
    if (secinfo->first_str == NULL)
      return true;
  
    /* FIXME: octets_per_byte.  */
    hdr = &elf_section_data (sec->output_section)->this_hdr;
    if (hdr->sh_offset == (file_ptr) -1)
      {
        /* We must compress this section.  Write output to the
  	 buffer.  */
        contents = hdr->contents;
        if ((sec->output_section->flags & SEC_ELF_COMPRESS) == 0
  	  || contents == NULL)
  	abort ();
      }
    else
      {
        contents = NULL;
        pos = sec->output_section->filepos + sec->output_offset;
        if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
  	return false;
      }
  
    if (! sec_merge_emit (output_bfd, secinfo->first_str, contents,
  			sec->output_offset))
      return false;
  
    return true;
  }
  
  /* Adjust an address in the SEC_MERGE section.  Given OFFSET within
     *PSEC, this returns the new offset in the adjusted SEC_MERGE
     section and writes the new section back into *PSEC.  */
  
  bfd_vma
  _bfd_merged_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, asection **psec,
  			    void *psecinfo, bfd_vma offset)
  {
    struct sec_merge_sec_info *secinfo;
    struct sec_merge_hash_entry *entry;
    unsigned char *p;
    asection *sec = *psec;
  
    secinfo = (struct sec_merge_sec_info *) psecinfo;
  
    if (!secinfo)
      return offset;
  
    if (offset >= sec->rawsize)
      {
        if (offset > sec->rawsize)
  	_bfd_error_handler
  	  /* xgettext:c-format */
  	  (_("%pB: access beyond end of merged section (%" PRId64 ")"),
  	   sec->owner, (int64_t) offset);
        return secinfo->first_str ? sec->size : 0;
      }
  
    if (secinfo->htab->strings)
      {
        if (sec->entsize == 1)
  	{
  	  p = secinfo->contents + offset - 1;
  	  while (p >= secinfo->contents && *p)
  	    --p;
  	  ++p;
  	}
        else
  	{
  	  p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
  	  p -= sec->entsize;
  	  while (p >= secinfo->contents)
  	    {
  	      unsigned int i;
  
  	      for (i = 0; i < sec->entsize; ++i)
  		if (p[i] != '\0')
  		  break;
  	      if (i == sec->entsize)
  		break;
  	      p -= sec->entsize;
  	    }
  	  p += sec->entsize;
  	}
      }
    else
      {
        p = secinfo->contents + (offset / sec->entsize) * sec->entsize;
      }
    entry = sec_merge_hash_lookup (secinfo->htab, (char *) p, 0, false);
    if (!entry)
      {
        if (! secinfo->htab->strings)
  	abort ();
        /* This should only happen if somebody points into the padding
  	 after a NUL character but before next entity.  */
        if (*p)
  	abort ();
        if (! secinfo->htab->first)
  	abort ();
        entry = secinfo->htab->first;
        p = (secinfo->contents + (offset / sec->entsize + 1) * sec->entsize
  	   - entry->len);
      }
  
    *psec = entry->secinfo->sec;
    return entry->u.index + (secinfo->contents + offset - p);
  }
  
  /* Tidy up when done.  */
  
  void
  _bfd_merge_sections_free (void *xsinfo)
  {
    struct sec_merge_info *sinfo;
  
    for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next)
      {
        bfd_hash_table_free (&sinfo->htab->table);
        free (sinfo->htab);
      }
  }
  