* fix and test MSVC AVX2 build
* treat msbuild warnings as errors
* fix incorrect MSVC 2019 compiler warning
* fix MSVC error D9035: option 'Gm' has been deprecated and will be removed in a future release
The input bounds checks were buggy because they were only breaking from
the inner loop, not the outer loop. The fuzzers found this immediately.
The fix is to use `goto _out` instead of `break`.
This condition can happen on corrupted inputs.
I've benchmarked before and after on x86-64 and there were small changes
in performance, some positive, and some negative, and they end up about
balacing out.
Credit to OSS-Fuzz
Add generic C versions of the fast decoding loops to serve architectures
that don't have an assembly implementation. Also allow selecting the C
decoding loop over the assembly decoding loop through a zstd
decompression parameter `ZSTD_d_disableHuffmanAssembly`.
I benchmarked on my Intel i9-9900K and my Macbook Air with an M1 processor.
The benchmark command forces zstd to compress without any matches, using
only literals compression, and measures only Huffman decompression speed:
```
zstd -b1e1 --compress-literals --zstd=tlen=131072 silesia.tar
```
The new fast decoding loops outperform the previous implementation uniformly,
but don't beat the x86-64 assembly. Additionally, the fast C decoding loops suffer
from the same stability problems that we've seen in the past, where the assembly
version doesn't. So even though clang gets close to assembly on x86-64, it still
has stability issues.
| Arch | Function | Compiler | Default (MB/s) | Assembly (MB/s) | Fast (MB/s) |
|---------|----------------|--------------|----------------|-----------------|-------------|
| x86-64 | decompress 4X1 | gcc-12.2.0 | 1029.6 | 1308.1 | 1208.1 |
| x86-64 | decompress 4X1 | clang-14.0.6 | 1019.3 | 1305.6 | 1276.3 |
| x86-64 | decompress 4X2 | gcc-12.2.0 | 1348.5 | 1657.0 | 1374.1 |
| x86-64 | decompress 4X2 | clang-14.0.6 | 1027.6 | 1659.9 | 1468.1 |
| aarch64 | decompress 4X1 | clang-12.0.5 | 1081.0 | N/A | 1234.9 |
| aarch64 | decompress 4X2 | clang-12.0.5 | 1270.0 | N/A | 1516.6 |
Reported by @shulib :
the specification for 4-streams mode
doesn't work when the amount of literals to compress is 5 bytes.
Extending it, it also doesn't work for sizes 1 or 2.
This patch updates the specification and the implementation
to require a minimum of 6 literals to trigger or accept the 4-streams mode.
The impact is expected to be a no-op :
the 4-streams mode is never triggered for such small quantity of literals anyway,
since it would be wasteful (it costs ~7.3 bytes more than single-stream mode).
An informal lower limit is set at ~256 bytes,
so the technical minimum is very far from this limit.
This is just meant for completeness of the specification.
```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora \) -prune -o -type f);
do
sed -i 's/Facebook, Inc\./Meta Platforms, Inc. and affiliates./' $f;
done
```
Move portability macros to `lib/common/portability_macros.h`. This file
only contains platform/feature detection (e.g. 0/1 macros). This file is
shared between C and ASM code, so it cannot include any C code.
Rename `HUF_` ASM macros to be `ZSTD_` prefixed, and move to the new
header.
Restrict `ZSTD_ASM_SUPPORTED` to `__GNUC__`, because we need the GAS
assembler.
Finally, only include the ASM code if we are actually going to use it.
This disables it on all Windows platforms, which should resolve the
problem brought up in Issue #2789.
* When dynamic dispatching to bmi2 add lzcnt and bmi to the
TARGET_ATTRIBUTE.
* Centralize the bmi2 TARGET_ATTRIBUTE definition to
BMI2_TARGET_ATTRIBUTE so we can change it in the future.
* Only enable bmi2 when both bmi1 & bmi2 are supported. There shouldn't
be any cases where bmi2 is supported but bmi1 isn't. But, since we are
using the instruction we should check bmi1 as well.
PR #2784 introduced a bug in the decompressor that caused some valid
inputs to fail to decompress. The bitstream isn't reloaded after the 4X*
loop if the number of elements remaining is small enough, causing us to
read more bits than are available in the bitcontainer.
This was caught by the MSAN fuzzer in OSS-Fuzz because the assembly
implementation isn't used in the MSAN build.
Credit to OSS-Fuzz.
Commit d7ef97a013
("[build] Fix oss-fuzz build with the dataflow sanitizer") broke
build inside Linux-kernel after 'import', as it no longer can
conditionally remove ZSTD_MEMORY_SANITIZER definition from
the #if DEF_A || DEF_B block. This emits -Wundef warning which
can be treated as error.
Split this preprocessor condition into two separate conditions
to fix this.
Fixes: d7ef97a013 ("[build] Fix oss-fuzz build with the dataflow sanitizer")
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
* Switch to yearless copyright per FB policy
* Fix up SPDX-License-Identifier lines in `contrib/linux-kernel` sources
* Add zstd copyright/license header to the `contrib/linux-kernel` sources
* Update the `tests/test-license.py` to check for yearless copyright
* Improvements to `tests/test-license.py`
* Check `contrib/linux-kernel` in `tests/test-license.py`
* Move `counting` to a struct in `FSE_decompress_wksp_body()`
* Fix error code in `FSE_decompress_wksp_body()`
* Rename a variable in `HUF_ReadDTableX2_Workspace`
The unused function definitions are hidden behind a
`#ifndef ZSTD_NO_UNUSED_FUNCTIONS` check.
Initially hiding all functions which are unused and take up more than
2KB of stack space, because these will show up as warnings in the
Linux Kernel build system.
* All copyright lines now have -2020 instead of -present
* All copyright lines include "Facebook, Inc"
* All licenses are now standardized
The copyright in `threading.{h,c}` is not changed because it comes from
zstdmt.
The copyright and license of `divsufsort.{h,c}` is not changed.
This has no measurable impact on large files but improves small file
decompression by ~1-2% for 10kB, benchmarked with:
head -c 10000 silesia.tar > /tmp/test
make CC=/usr/local/bin/clang-9 BUILD_STATIC=1 && ./lzbench -ezstd -t1,5 /tmp/test
