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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/contrib/binutils/bfd/merge.c |
/* SEC_MERGE support.
Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007
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 2 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 "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? */
bfd_boolean 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 = 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, bfd_boolean create)
{
register const unsigned char *s;
register unsigned long hash;
register 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 *)
sec_merge_hash_newfunc (NULL, &table->table, string));
if (hashp == NULL)
return NULL;
hashp->root.string = string;
hashp->root.hash = hash;
hashp->len = len;
hashp->alignment = alignment;
hashp->root.next = table->table.table[index];
table->table.table[index] = (struct bfd_hash_entry *) hashp;
return hashp;
}
/* Create a new hash table. */
static struct sec_merge_hash *
sec_merge_init (unsigned int entsize, bfd_boolean strings)
{
struct sec_merge_hash *table;
table = 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)
{
register 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 bfd_boolean
sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
{
struct sec_merge_sec_info *secinfo = entry->secinfo;
asection *sec = secinfo->sec;
char *pad = NULL;
bfd_size_type off = 0;
int alignment_power = sec->output_section->alignment_power;
if (alignment_power)
{
pad = bfd_zmalloc ((bfd_size_type) 1 << alignment_power);
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)
{
if (bfd_bwrite (pad, len, abfd) != len)
goto err;
off += len;
}
str = entry->root.string;
len = entry->len;
if (bfd_bwrite (str, len, abfd) != len)
goto err;
off += len;
}
/* Trailing alignment needed? */
off = sec->size - off;
if (off != 0
&& bfd_bwrite (pad, off, abfd) != off)
goto err;
if (pad != NULL)
free (pad);
return TRUE;
err:
if (pad != NULL)
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. */
bfd_boolean
_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 align;
bfd_size_type amt;
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->flags & SEC_RELOC) != 0)
{
/* We aren't prepared to handle relocations in merged sections. */
return TRUE;
}
align = sec->alignment_power;
if ((sec->entsize < (unsigned) 1 << align
&& ((sec->entsize & (sec->entsize - 1))
|| !(sec->flags & SEC_STRINGS)))
|| (sec->entsize > (unsigned) 1 << align
&& (sec->entsize & (((unsigned) 1 << 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 = 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) + sec->size - 1;
*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 (! bfd_get_section_contents (sec->owner, sec, secinfo->contents,
0, sec->size))
goto error_return;
return TRUE;
error_return:
*psecinfo = NULL;
return FALSE;
}
/* Record one section into the hash table. */
static bfd_boolean
record_section (struct sec_merge_info *sinfo,
struct sec_merge_sec_info *secinfo)
{
asection *sec = secinfo->sec;
struct sec_merge_hash_entry *entry;
bfd_boolean 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;
}
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 void
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 = bfd_malloc (amt);
if (array == NULL)
goto alloc_failure;
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;
}
}
alloc_failure:
if (array)
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;
if (secinfo->sec->alignment_power != 0)
{
bfd_size_type align = (bfd_size_type) 1 << secinfo->sec->alignment_power;
secinfo->sec->size = (secinfo->sec->size + align - 1) & -align;
}
/* 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);
}
}
}
/* This function is called once after all SEC_MERGE sections are registered
with _bfd_merge_section. */
bfd_boolean
_bfd_merge_sections (bfd *abfd ATTRIBUTE_UNUSED,
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;
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. */
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))
break;
if (secinfo)
continue;
if (sinfo->htab->first == NULL)
continue;
if (sinfo->htab->strings)
merge_strings (sinfo);
else
{
struct sec_merge_hash_entry *e;
bfd_size_type size = 0;
/* 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;
}
/* 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. */
bfd_boolean
_bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
{
struct sec_merge_sec_info *secinfo;
file_ptr pos;
secinfo = (struct sec_merge_sec_info *) psecinfo;
if (secinfo->first_str == NULL)
return TRUE;
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))
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 (offset >= sec->rawsize)
{
if (offset > sec->rawsize)
{
(*_bfd_error_handler)
(_("%s: access beyond end of merged section (%ld)"),
bfd_get_filename (sec->owner), (long) 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);
}