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authorWill Newton <will.newton@linaro.org>2014-04-02 16:04:12 +0100
committerWill Newton <will.newton@linaro.org>2014-06-23 14:13:30 +0100
commitf393b4aaedd32238738708f6b180fe91a0ae85f8 (patch)
treeb8ea925484b201738d81a398b3eaccebb216d0ba /elf
parentac60763eac3d43b7234dd21286ad3ec3f17957fc (diff)
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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.
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-lookup.c304
1 files changed, 159 insertions, 145 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index be6f76f..896e1d2 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -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. */