diff options
| author | Noel Gordon <noel@chromium.org> | 2022-12-08 02:46:29 +0000 |
|---|---|---|
| committer | Copybara-Service <copybara-worker@google.com> | 2022-12-07 18:52:11 -0800 |
| commit | 18d27fa10b237fdfcbd8f0c65c19fe009981a3bc (patch) | |
| tree | 0d6bd54e4d47a4f1ef0c2bd4042df7faab39b73d | |
| parent | d866d41e168ec04545bb17031fa911007a0581f4 (diff) | |
| download | zlib-18d27fa10b237fdfcbd8f0c65c19fe009981a3bc.tar.gz | |
[zlib] make insert_string_simd load window data with zmemcpy
Undefined behavior santizer (UBSan) notes that window data loaded
using the existing code makes C++ compilers unhappy.
C++ Compilers expect data alignment: so loading from an unaligned
object is undefined C++ behaviour.
Fix this: use zmemcpy to load the window data. All optimizing C++
tested (see bug) output the same instruction sequence, before and
after this change. So no change in performance.
Bug: 1399295
Test: zlib_bench gzip --compression 6 ~/snappy/testdata/*
Change-Id: I90cfd66c803686c3834d88c3bc33833216598836
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4086462
Reviewed-by: Adenilson Cavalcanti <cavalcantii@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1080742}
NOKEYCHECK=True
GitOrigin-RevId: 36bfeb91012cd6c6897eda645e5375abf14c1c01
| -rw-r--r-- | contrib/optimizations/insert_string.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/contrib/optimizations/insert_string.h b/contrib/optimizations/insert_string.h index 2a04f69..c6a296a 100644 --- a/contrib/optimizations/insert_string.h +++ b/contrib/optimizations/insert_string.h @@ -57,10 +57,9 @@ TARGET_CPU_WITH_CRC local INLINE Pos insert_string_simd(deflate_state* const s, const Pos str) { Pos ret; - unsigned *ip, val, h = 0; + unsigned val, h = 0; - ip = (unsigned*)&s->window[str]; - val = *ip; + zmemcpy(&val, &s->window[str], sizeof(val)); if (s->level >= 6) val &= 0xFFFFFF; |