Multi-threaded static library require -pthread to correctly link and works.
The pkg-config we provide tho only works with dynamic multi-threaded library
and won't provide the correct libs and cflags values if lib-mt is used.
To handle this, introduce an env variable MT to permit advanced user to
install and generate a correct pkg-config file for lib-mt or detect if
lib-mt target is called.
With MT env set on calling make install-pc, libzstd.pc.in is a
pkg-config file for a multi-threaded static library.
On calling make lib-mt, a libzstd.pc is generated for a multi-threaded
static library as it's what asked by the user by forcing it.
libzstd.pc is changed to PHONY to force regeneration of it on calling
lib targets or install-pc to handle case where the same directory is
used for mixed compilation.
This was notice while migrating from meson to make build system where
meson generates a correct .pc file while make doesn't.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
gcc in the linux kernel was not unrolling the inner loops of the Huffman
decoder, which was destroying decoding performance. The compiler was
generating crazy code with all sorts of branches. I suspect because of
Spectre mitigations, but I'm not certain. Once the loops were manually
unrolled, performance was restored.
Additionally, when gcc couldn't prove that the variable left shift in
the 4X2 decode loop wasn't greater than 63, it inserted checks to verify
it. To fix this, mask `entry.nbBits & 0x3F`, which allows gcc to eliete
this check. This is a no op, because `entry.nbBits` is guaranteed to be
less than 64.
Lastly, introduce the `HUF_DISABLE_FAST_DECODE` macro to disable the
fast C loops for Issue #3762. So if even after this change, there is a
performance regression, users can opt-out at compile time.
1. Follow the scheme introduced in PR #2501 for both `zdict.h` and `zstd_errors.h`.
2. If the `*_VISIBLE` macro isn't set, but the `*_VISIBILITY` macro is, use that.
Also make this change for `zstd.h`, since we probably shouldn't have changed
that macro name without backward compatibility in the first place.
3. Change all references to `*_VISIBILITY` to `*_VISIBLE`.
Fixes#3359.
`zstd_errors.h` and `zdict.h` are public headers, so they deserve to be
in the root `lib/` directory with `zstd.h`, not mixed in with our private
headers.
This diff reorganizes the `lib/Makefile` to extract various settings that a
user would normally invoke together (supposing that they were aware of them)
if they were trying to build the smallest `libzstd` possible. It collects
these settings under a master setting `ZSTD_LIB_MIN_SIZE`.
Also document this new option.
