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elf/dl-lookup.c: Move STB_GNU_UNIQUE handling to a function 

Move handling of STB_GNU_UNIQUE symbols to a separate function
from do_lookup_x in order to make the code more readable.

The new function gets inlined with gcc 4.8 on ARM and the
do_lookup_x code becomes a few bytes smaller.

ChangeLog:

2014-06-23  Will Newton  <will.newton@linaro.org>

	* elf/dl-lookup.c (do_lookup_unique): New function.
	(do_lookup_x): Move STB_GNU_UNIQUE handling code
	to a separate function.
hjl/release/2.20/master
Will Newton 12 years ago
parent
ac60763eac
commit
f393b4aaed
2 changed files with 165 additions and 145 deletions
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      ChangeLog
  2. 304
      elf/dl-lookup.c

6
ChangeLog
View File

@ -1,3 +1,9 @@
2014-06-23 Will Newton <will.newton@linaro.org>
* elf/dl-lookup.c (do_lookup_unique): New function.
(do_lookup_x): Move STB_GNU_UNIQUE handling code
to a separate function.
2014-06-23 Andreas Schwab <schwab@suse.de>
[BZ #17079]

304
elf/dl-lookup.c
View File

@ -186,6 +186,162 @@ check_match (const char *const undef_name,
return sym;
}
/* Utility function for do_lookup_x. Lookup an STB_GNU_UNIQUE symbol
in the unique symbol table, creating a new entry if necessary.
Return the matching symbol in RESULT. */
static void
do_lookup_unique (const char *undef_name, uint_fast32_t new_hash,
const struct link_map *map, struct sym_val *result,
int type_class, const ElfW(Sym) *sym, const char *strtab,
const ElfW(Sym) *ref, const struct link_map *undef_map)
{
/* We have to determine whether we already found a
symbol with this name before. If not then we have to
add it to the search table. If we already found a
definition we have to use it. */
void enter (struct unique_sym *table, size_t size,
unsigned int hash, const char *name,
const ElfW(Sym) *sym, const struct link_map *map)
{
size_t idx = hash % size;
size_t hash2 = 1 + hash % (size - 2);
while (table[idx].name != NULL)
{
idx += hash2;
if (idx >= size)
idx -= size;
}
table[idx].hashval = hash;
table[idx].name = name;
table[idx].sym = sym;
table[idx].map = map;
}
struct unique_sym_table *tab
= &GL(dl_ns)[map->l_ns]._ns_unique_sym_table;
__rtld_lock_lock_recursive (tab->lock);
struct unique_sym *entries = tab->entries;
size_t size = tab->size;
if (entries != NULL)
{
size_t idx = new_hash % size;
size_t hash2 = 1 + new_hash % (size - 2);
while (1)
{
if (entries[idx].hashval == new_hash
&& strcmp (entries[idx].name, undef_name) == 0)
{
if ((type_class & ELF_RTYPE_CLASS_COPY) != 0)
{
/* We possibly have to initialize the central
copy from the copy addressed through the
relocation. */
result->s = sym;
result->m = (struct link_map *) map;
}
else
{
result->s = entries[idx].sym;
result->m = (struct link_map *) entries[idx].map;
}
__rtld_lock_unlock_recursive (tab->lock);
return;
}
if (entries[idx].name == NULL)
break;
idx += hash2;
if (idx >= size)
idx -= size;
}
if (size * 3 <= tab->n_elements * 4)
{
/* Expand the table. */
#ifdef RTLD_CHECK_FOREIGN_CALL
/* This must not happen during runtime relocations. */
assert (!RTLD_CHECK_FOREIGN_CALL);
#endif
size_t newsize = _dl_higher_prime_number (size + 1);
struct unique_sym *newentries
= calloc (sizeof (struct unique_sym), newsize);
if (newentries == NULL)
{
nomem:
__rtld_lock_unlock_recursive (tab->lock);
_dl_fatal_printf ("out of memory\n");
}
for (idx = 0; idx < size; ++idx)
if (entries[idx].name != NULL)
enter (newentries, newsize, entries[idx].hashval,
entries[idx].name, entries[idx].sym,
entries[idx].map);
tab->free (entries);
tab->size = newsize;
size = newsize;
entries = tab->entries = newentries;
tab->free = free;
}
}
else
{
#ifdef RTLD_CHECK_FOREIGN_CALL
/* This must not happen during runtime relocations. */
assert (!RTLD_CHECK_FOREIGN_CALL);
#endif
#ifdef SHARED
/* If tab->entries is NULL, but tab->size is not, it means
this is the second, conflict finding, lookup for
LD_TRACE_PRELINKING in _dl_debug_bindings. Don't
allocate anything and don't enter anything into the
hash table. */
if (__glibc_unlikely (tab->size))
{
assert (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK);
goto success;
}
#endif
#define INITIAL_NUNIQUE_SYM_TABLE 31
size = INITIAL_NUNIQUE_SYM_TABLE;
entries = calloc (sizeof (struct unique_sym), size);
if (entries == NULL)
goto nomem;
tab->entries = entries;
tab->size = size;
tab->free = free;
}
if ((type_class & ELF_RTYPE_CLASS_COPY) != 0)
enter (entries, size, new_hash, strtab + sym->st_name, ref,
undef_map);
else
{
enter (entries, size, new_hash, strtab + sym->st_name, sym, map);
if (map->l_type == lt_loaded)
/* Make sure we don't unload this object by
setting the appropriate flag. */
((struct link_map *) map)->l_flags_1 |= DF_1_NODELETE;
}
++tab->n_elements;
#ifdef SHARED
success:
#endif
__rtld_lock_unlock_recursive (tab->lock);
result->s = sym;
result->m = (struct link_map *) map;
}
/* Inner part of the lookup functions. We return a value > 0 if we
found the symbol, the value 0 if nothing is found and < 0 if
@ -323,157 +479,15 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
}
/* FALLTHROUGH */
case STB_GLOBAL:
success:
/* Global definition. Just what we need. */
result->s = sym;
result->m = (struct link_map *) map;
return 1;
case STB_GNU_UNIQUE:;
/* We have to determine whether we already found a
symbol with this name before. If not then we have to
add it to the search table. If we already found a
definition we have to use it. */
void enter (struct unique_sym *table, size_t size,
unsigned int hash, const char *name,
const ElfW(Sym) *sym, const struct link_map *map)
{
size_t idx = hash % size;
size_t hash2 = 1 + hash % (size - 2);
while (table[idx].name != NULL)
{
idx += hash2;
if (idx >= size)
idx -= size;
}
table[idx].hashval = hash;
table[idx].name = name;
table[idx].sym = sym;
table[idx].map = map;
}
struct unique_sym_table *tab
= &GL(dl_ns)[map->l_ns]._ns_unique_sym_table;
__rtld_lock_lock_recursive (tab->lock);
struct unique_sym *entries = tab->entries;
size_t size = tab->size;
if (entries != NULL)
{
size_t idx = new_hash % size;
size_t hash2 = 1 + new_hash % (size - 2);
while (1)
{
if (entries[idx].hashval == new_hash
&& strcmp (entries[idx].name, undef_name) == 0)
{
if ((type_class & ELF_RTYPE_CLASS_COPY) != 0)
{
/* We possibly have to initialize the central
copy from the copy addressed through the
relocation. */
result->s = sym;
result->m = (struct link_map *) map;
}
else
{
result->s = entries[idx].sym;
result->m = (struct link_map *) entries[idx].map;
}
__rtld_lock_unlock_recursive (tab->lock);
return 1;
}
if (entries[idx].name == NULL)
break;
idx += hash2;
if (idx >= size)
idx -= size;
}
if (size * 3 <= tab->n_elements * 4)
{
/* Expand the table. */
#ifdef RTLD_CHECK_FOREIGN_CALL
/* This must not happen during runtime relocations. */
assert (!RTLD_CHECK_FOREIGN_CALL);
#endif
size_t newsize = _dl_higher_prime_number (size + 1);
struct unique_sym *newentries
= calloc (sizeof (struct unique_sym), newsize);
if (newentries == NULL)
{
nomem:
__rtld_lock_unlock_recursive (tab->lock);
_dl_fatal_printf ("out of memory\n");
}
for (idx = 0; idx < size; ++idx)
if (entries[idx].name != NULL)
enter (newentries, newsize, entries[idx].hashval,
entries[idx].name, entries[idx].sym,
entries[idx].map);
tab->free (entries);
tab->size = newsize;
size = newsize;
entries = tab->entries = newentries;
tab->free = free;
}
}
else
{
#ifdef RTLD_CHECK_FOREIGN_CALL
/* This must not happen during runtime relocations. */
assert (!RTLD_CHECK_FOREIGN_CALL);
#endif
#ifdef SHARED
/* If tab->entries is NULL, but tab->size is not, it means
this is the second, conflict finding, lookup for
LD_TRACE_PRELINKING in _dl_debug_bindings. Don't
allocate anything and don't enter anything into the
hash table. */
if (__glibc_unlikely (tab->size))
{
assert (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK);
__rtld_lock_unlock_recursive (tab->lock);
goto success;
}
#endif
#define INITIAL_NUNIQUE_SYM_TABLE 31
size = INITIAL_NUNIQUE_SYM_TABLE;
entries = calloc (sizeof (struct unique_sym), size);
if (entries == NULL)
goto nomem;
tab->entries = entries;
tab->size = size;
tab->free = free;
}
if ((type_class & ELF_RTYPE_CLASS_COPY) != 0)
enter (entries, size, new_hash, strtab + sym->st_name, ref,
undef_map);
else
{
enter (entries, size, new_hash, strtab + sym->st_name, sym,
map);
if (map->l_type == lt_loaded)
/* Make sure we don't unload this object by
setting the appropriate flag. */
((struct link_map *) map)->l_flags_1 |= DF_1_NODELETE;
}
++tab->n_elements;
__rtld_lock_unlock_recursive (tab->lock);
goto success;
do_lookup_unique (undef_name, new_hash, map, result, type_class,
sym, strtab, ref, undef_map);
return 1;
default:
/* Local symbols are ignored. */

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