It is no longer necessary to get good performance, there is only a small
speed difference between -O2 and -O3, so just stick to the default of
-O2.
This also fixes the stack space usage on parisc. The compiler was buggy
for -O3 and used ~3KB of stack space for several functions. With -O2 the
problem is completely resolved, and stack space is back to a few hundred
bytes.
Additionally, we get a large code size win on gcc:
| Compiler | Before (Bytes) | After (Bytes) | Delta (Bytes) |
|----------|----------------|---------------|---------------|
| gcc-11 | 952754 | 738954 | -213800 |
| clang-12 | 976290 | 938826 | -37464 |
The optimal parser is unlikely to be used in the linux kernel in
practice. There is no reason these functions should be force inlined,
since we aren't gaining anything, and are losing build size.
| Compiler | Before (Bytes) | After (Bytes) | Delta (Bytes) |
|----------|----------------|---------------|---------------|
| gcc-11 | 1142090 | 952754 | -189336 |
| clang-12 | 1228402 | 976290 | -252112 |
This is a temporary solution pending the resolution of Issue #2862 in
the `dev` branch.
Switch to a macro `ZSTD_FALLTHROUGH;` instead of a comment. On supported
compilers this uses an attribute, otherwise it becomes a comment.
This is necessary to be compatible with clang's `-Wfall-through`, and
gcc's `-Wfall-through=2` which don't support comments. Without this the
linux build emits a bunch of warnings.
Instead of calling `ZSTD_compress_advanced()` and
`ZSTD_initCStream_advanced()`, which each take a `ZSTD_parameters` by
value, use the new advanced API.
Stack usage went from 2024 -> 1944.
Replace kernel-style comments with regular comments.
E.g.
```
/** Before */
/* After */
/**
* Before
*/
/*
* After
*/
/***********************************
* Before
***********************************/
/* *********************************
* After
***********************************/
```
* 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`
Expose the zstd headers in `include/linux` to avoid struct duplication.
This makes the member names not follow Kernel style guidelines, and
exposes the zstd symbols. But, the LMKL reviewers are okay with that.
Add the kernel wrapper API. This keeps the same API and semantics as the
existing kernel API with name changes to be more kernel style and avoid
symbol collisions with zstd.
Rename ADDRESS_SANITIZER -> ZSTD_ADDRESS_SANITIZER and same for
MEMORY_SANITIZER. Also set it to 0/1 instead of checking for defined.
This allows the user to override ASAN/MSAN detection for platforms that
don't support it.
Add decompress_sources.h, which includes all the decompression .c files.
This is used for kernel decompression.
Also, add a test which checks that including decompress_sources.h works.
