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WIP mul64 dlsym optimization

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Change-Id: I4caf4f14deb7a106c17e3ca89bdff5cd89f9541b
This commit is contained in:
Florian Weimer 2019-11-11 16:09:32 +01:00
parent 0fa7402cbb
commit 060d8b9ced
2 changed files with 9 additions and 12 deletions
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18
elf/dl-lookup.c
View File

@ -396,16 +396,15 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
& (bitmask_word >> hashbit2) & 1))
{
Elf32_Word bucket;
if (map->l_nbuckets > 1)
if (powerof2 (map->l_nbuckets))
bucket = map->l_gnu_buckets[new_hash & (map->l_nbuckets - 1)];
else
{
uint32_t quotient
= divopt_32 (new_hash, map->l_nbuckets_multiplier,
map->l_nbuckets_multiplier_shift);
= ((unsigned __int128) map->l_nbuckets_multiplier * ((uint64_t) new_hash + 1)) >> 64;
uint32_t remainder = new_hash - map->l_nbuckets * quotient;
bucket = map->l_gnu_buckets[remainder];
}
else
bucket = map->l_gnu_buckets[0];
if (bucket != 0)
{
@ -942,11 +941,10 @@ _dl_setup_hash (struct link_map *map)
/* Initialize MIPS xhash translation table. */
ELF_MACHINE_XHASH_SETUP (hash32, symbias, map);
if (map->l_nbuckets >= 2)
map->l_nbuckets_multiplier_shift
= precompute_divopt_32 (map->l_nbuckets,
&map->l_nbuckets_multiplier);
if (powerof2 (map->l_nbuckets))
map->l_nbuckets_multiplier = __builtin_ctz (map->l_nbuckets);
else
map->l_nbuckets_multiplier = ((unsigned __int128) 1 << 64) / map->l_nbuckets;
return;
}

3
include/link.h
View File

@ -153,8 +153,7 @@ struct link_map
/* Symbol hash table. */
Elf_Symndx l_nbuckets;
uint32_t l_nbuckets_multiplier;
int l_nbuckets_multiplier_shift;
uint64_t l_nbuckets_multiplier;
Elf32_Word l_gnu_bitmask_idxbits;
Elf32_Word l_gnu_shift;
const ElfW(Addr) *l_gnu_bitmask;