liblzma: Add fast CRC64 for 32/64-bit x86 using SSSE3 + SSE4.1 + CLMUL.

It also works on E2K as it supports these intrinsics.

On x86-64 runtime detection is used so the code keeps working on
older processors too. A CLMUL-only build can be done by using
-msse4.1 -mpclmul in CFLAGS and this will reduce the library
size since the generic implementation and its 8 KiB lookup table
will be omitted.

On 32-bit x86 this isn't used by default for now because by default
on 32-bit x86 the separate assembly file crc64_x86.S is used.
If --disable-assembler is used then this new CLMUL code is used
the same way as on 64-bit x86. However, a CLMUL-only build
(-msse4.1 -mpclmul) won't omit the 8 KiB lookup table on
32-bit x86 due to a currently-missing check for disabled
assembler usage.

The configure.ac check should be such that the code won't be
built if something in the toolchain doesn't support it but
--disable-clmul-crc option can be used to unconditionally
disable this feature.

CLMUL speeds up decompression of files that have compressed very
well (assuming CRC64 is used as a check type). It is know that
the CLMUL code is significantly slower than the generic code for
tiny inputs (especially 1-8 bytes but up to 16 bytes). If that
is a real-world problem then there is already a commented-out
variant that uses the generic version for small inputs.

Thanks to Ilya Kurdyukov for the original patch which was
derived from a white paper from Intel [1] (published in 2009)
and public domain code from [2] (released in 2016).

[1] https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
[2] https://github.com/rawrunprotected/crc

1 files changed, 24 insertions, 2 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 11f3a05..ec44bac 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -49,8 +49,10 @@
 cmake_minimum_required(VERSION 3.13...3.16 FATAL_ERROR)
 
 include(CMakePushCheckState)
+include(CheckIncludeFile)
 include(CheckSymbolExists)
 include(CheckStructHasMember)
+include(CheckCSourceCompiles)
 include(cmake/tuklib_integer.cmake)
 include(cmake/tuklib_cpucores.cmake)
 include(cmake/tuklib_physmem.cmake)
@@ -402,14 +404,16 @@ check_c_source_compiles("
 cmake_pop_check_state()
 tuklib_add_definition_if(liblzma HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR)
 
+# cpuid.h
+check_include_file(cpuid.h HAVE_CPUID_H)
+tuklib_add_definition_if(liblzma HAVE_CPUID_H)
+
 # immintrin.h:
-include(CheckIncludeFile)
 check_include_file(immintrin.h HAVE_IMMINTRIN_H)
 if(HAVE_IMMINTRIN_H)
     target_compile_definitions(liblzma PRIVATE HAVE_IMMINTRIN_H)
 
     # SSE2 intrinsics:
-    include(CheckCSourceCompiles)
     check_c_source_compiles("
             #include <immintrin.h>
             int main(void)
@@ -421,6 +425,24 @@ if(HAVE_IMMINTRIN_H)
         "
         HAVE__MM_MOVEMASK_EPI8)
     tuklib_add_definition_if(liblzma HAVE__MM_MOVEMASK_EPI8)
+
+    # CLMUL intrinsic:
+    check_c_source_compiles("
+            #include <immintrin.h>
+            #if defined(__e2k__) && __iset__ < 6
+            #   error
+            #endif
+            #if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
+            __attribute__((__target__(\"ssse3,sse4.1,pclmul\")))
+            #endif
+            __m128i my_clmul(__m128i a, __m128i b)
+            {
+                return _mm_clmulepi64_si128(a, b, 0);
+            }
+            int main(void) { return 0; }
+    "
+    HAVE_USABLE_CLMUL)
+    tuklib_add_definition_if(liblzma HAVE_USABLE_CLMUL)
 endif()
 
 # Support -fvisiblity=hidden when building shared liblzma.