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authorLasse Collin <lasse.collin@tukaani.org>2022-11-14 16:00:52 +0200
committerLasse Collin <lasse.collin@tukaani.org>2022-11-14 16:00:52 +0200
commiteb0f1450ad9f23dac03050d9c8375980240aee21 (patch)
tree2ccb523dc0277999d3629bad18e0c2e819d33b64 /CMakeLists.txt
parentTranslations: Update the Romanian translation. (diff)
downloadxz-eb0f1450ad9f23dac03050d9c8375980240aee21.tar.xz
liblzma: Use __attribute__((__constructor__)) if available.
This uses it for CRC table initializations when using --disable-small. It avoids mythread_once() overhead. It also means that then --disable-small --disable-threads is thread-safe if this attribute is supported.
Diffstat (limited to 'CMakeLists.txt')
-rw-r--r--CMakeLists.txt15
1 files changed, 15 insertions, 0 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e3af3bf6..11f3a055 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -48,6 +48,7 @@
cmake_minimum_required(VERSION 3.13...3.16 FATAL_ERROR)
+include(CMakePushCheckState)
include(CheckSymbolExists)
include(CheckStructHasMember)
include(cmake/tuklib_integer.cmake)
@@ -387,6 +388,20 @@ if(NOT TUKLIB_CPUCORES_FOUND OR NOT TUKLIB_PHYSMEM_FOUND)
"To build anyway, edit this CMakeLists.txt to ignore this error.")
endif()
+# Check for __attribute__((__constructor__)) support.
+# This needs -Werror because some compilers just warn
+# about this being unsupported.
+cmake_push_check_state()
+set(CMAKE_REQUIRED_FLAGS "-Werror")
+check_c_source_compiles("
+ __attribute__((__constructor__))
+ static void my_constructor_func(void) { return; }
+ int main(void) { return 0; }
+ "
+ HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR)
+cmake_pop_check_state()
+tuklib_add_definition_if(liblzma HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR)
+
# immintrin.h:
include(CheckIncludeFile)
check_include_file(immintrin.h HAVE_IMMINTRIN_H)