summaryrefslogtreecommitdiff
path: root/elf/dl-lookup.c
diff options
context:
space:
mode:
authorUlrich Drepper <drepper@redhat.com>2006-07-10 21:59:43 +0000
committerUlrich Drepper <drepper@redhat.com>2006-07-10 21:59:43 +0000
commit871b91589bf4f6dfe19d5987b0a05bd7cf936ecc (patch)
treee50affec0ae060520fbfac19071ee0bfc4348f31 /elf/dl-lookup.c
parentf3be81a91cdd1b42c47e4d8501dd96d0f1666520 (diff)
downloadglibc-871b91589bf4f6dfe19d5987b0a05bd7cf936ecc.tar.gz
* elf/dl-lookup.c (dl_new_hash): New functions.cvs/fedora-glibc-20060710T2206
(_dl_lookup_symbol_x): Rename hash to old_hash and don't compute value here. Compute new-style hash value. Pass new hash value and reference to variable with the old value to do_lookup_x. (_dl_setup_hash): If DT_GNU_HASH is defined, use it and not old-style hash table. (_dl_debug_bindings): Pass new hash value and reference to variable with the old value to do_lookup_x. * elf/do-lookup.h (do_lookup_x): Accept additional parameter with new-style hash value and change old-style hash value parameter to be a reference. Reoganize functions to determine whether new-style hash table is available. Only fall back on old-style table. If old-style hash value is needed, compute it here. * elf/dynamic-link.h (elf_get_dynamic_info): Relocate DT_GNU_HASH entry. * elf/elf.h: Define SHT_GNU_HASH, DT_GNU_HASH, DT_TLSDEC_PLT, DT_TLSDEC_GOT. Adjust DT_ADDRNUM. * include/link.h (struct link_map): Add l_gnu_bitmask_idxbits, l_gnu_shift, l_gnu_bitmask, l_gnu_buckets and l_gnu_chain_zero. * Makeconfig: If linker supports --hash-style option add it to all linker command lines to build DSOs. * config.make.in: Define have-hash-style. * configure.in: Test whether linker supports --hash-style option. * elf/dl-misc.c (_dl_name_match_p): Make MAP parameter const. * sysdeps/generic/ldsodefs.h: Adjust prototype.
Diffstat (limited to 'elf/dl-lookup.c')
-rw-r--r--elf/dl-lookup.c56
1 files changed, 47 insertions, 9 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 5a7bed16e5..7cfcc620a7 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -1,5 +1,5 @@
/* Look up a symbol in the loaded objects.
- Copyright (C) 1995-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 1995-2005, 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -72,6 +72,16 @@ struct sym_val
#include "do-lookup.h"
+static uint_fast32_t
+dl_new_hash (const char *s)
+{
+ uint_fast32_t h = 5381;
+ for (unsigned char c = *s; c != '\0'; c = *++s)
+ h = h * 33 + c;
+ return h & 0xffffffff;
+}
+
+
/* Add extra dependency on MAP to UNDEF_MAP. */
static int
internal_function
@@ -206,7 +216,8 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
const struct r_found_version *version,
int type_class, int flags, struct link_map *skip_map)
{
- const unsigned long int hash = _dl_elf_hash (undef_name);
+ const uint_fast32_t new_hash = dl_new_hash (undef_name);
+ unsigned long int old_hash = 0xffffffff;
struct sym_val current_value = { NULL, NULL };
struct r_scope_elem **scope = symbol_scope;
@@ -229,8 +240,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
/* Search the relevant loaded objects for a definition. */
for (size_t start = i; *scope != NULL; start = 0, ++scope)
{
- int res = do_lookup_x (undef_name, hash, *ref, &current_value, *scope,
- start, version, flags, skip_map, type_class);
+ int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+ &current_value, *scope, start, version, flags,
+ skip_map, type_class);
if (res > 0)
break;
@@ -301,9 +313,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
struct sym_val protected_value = { NULL, NULL };
for (scope = symbol_scope; *scope != NULL; i = 0, ++scope)
- if (do_lookup_x (undef_name, hash, *ref, &protected_value,
- *scope, i, version, flags, skip_map,
- ELF_RTYPE_CLASS_PLT) != 0)
+ if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+ &protected_value, *scope, i, version, flags,
+ skip_map, ELF_RTYPE_CLASS_PLT) != 0)
break;
if (protected_value.s != NULL && protected_value.m != undef_map)
@@ -352,6 +364,31 @@ _dl_setup_hash (struct link_map *map)
Elf_Symndx *hash;
Elf_Symndx nchain;
+ if (__builtin_expect (map->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+ + DT_THISPROCNUM + DT_VERSIONTAGNUM
+ + DT_EXTRANUM + DT_VALNUM] != NULL, 1))
+ {
+ Elf32_Word *hash32
+ = (void *) D_PTR (map, l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+ + DT_THISPROCNUM + DT_VERSIONTAGNUM
+ + DT_EXTRANUM + DT_VALNUM]);
+ map->l_nbuckets = *hash32++;
+ Elf32_Word symbias = *hash32++;
+ Elf32_Word bitmask_nwords = *hash32++;
+ /* Must be a power of two. */
+ assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
+ map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
+ map->l_gnu_shift = *hash32++;
+
+ map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
+ hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
+
+ map->l_gnu_buckets = hash32;
+ hash32 += map->l_nbuckets;
+ map->l_gnu_chain_zero = hash32 - symbias;
+ return;
+ }
+
if (!map->l_info[DT_HASH])
return;
hash = (void *) D_PTR (map, l_info[DT_HASH]);
@@ -399,9 +436,10 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
|| GLRO(dl_trace_prelink_map) == GL(dl_ns)[LM_ID_BASE]._ns_loaded)
&& undef_map != GL(dl_ns)[LM_ID_BASE]._ns_loaded)
{
- const unsigned long int hash = _dl_elf_hash (undef_name);
+ const uint_fast32_t new_hash = dl_new_hash (undef_name);
+ unsigned long int old_hash = 0xffffffff;
- do_lookup_x (undef_name, hash, *ref, &val,
+ do_lookup_x (undef_name, new_hash, &old_hash, *ref, &val,
undef_map->l_local_scope[0], 0, version, 0, NULL,
type_class);