mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-22 10:42:39 +01:00
130f9a4a59
Summary: Always respect existing CMAKE_REQUIRED_FLAGS when adding additional ones. This is important when cross compiling where --sysroot and -target were already added. In particular, this is needed when cross compiling from Darwin to Linux, since --sysroot is required to find headers and libraries. Cmake has a similar bug in check_include_file[_cxx] where CMAKE_REQUIRED_LIBRARIES isn't passed, which causes try_compile to fail. (please see https://gitlab.kitware.com/cmake/cmake/merge_requests/1620) Reviewers: compnerd, silvas, beanz, brad.king Reviewed By: compnerd Subscribers: mgorny, llvm-commits Differential Revision: https://reviews.llvm.org/D41568 llvm-svn: 321434
107 lines
3.4 KiB
CMake
107 lines
3.4 KiB
CMake
# atomic builtins are required for threading support.
|
|
|
|
INCLUDE(CheckCXXSourceCompiles)
|
|
INCLUDE(CheckLibraryExists)
|
|
|
|
# Sometimes linking against libatomic is required for atomic ops, if
|
|
# the platform doesn't support lock-free atomics.
|
|
|
|
function(check_working_cxx_atomics varname)
|
|
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
|
|
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11")
|
|
CHECK_CXX_SOURCE_COMPILES("
|
|
#include <atomic>
|
|
std::atomic<int> x;
|
|
int main() {
|
|
return x;
|
|
}
|
|
" ${varname})
|
|
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
|
|
endfunction(check_working_cxx_atomics)
|
|
|
|
function(check_working_cxx_atomics64 varname)
|
|
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
|
|
set(CMAKE_REQUIRED_FLAGS "-std=c++11 ${CMAKE_REQUIRED_FLAGS}")
|
|
CHECK_CXX_SOURCE_COMPILES("
|
|
#include <atomic>
|
|
#include <cstdint>
|
|
std::atomic<uint64_t> x (0);
|
|
int main() {
|
|
uint64_t i = x.load(std::memory_order_relaxed);
|
|
return 0;
|
|
}
|
|
" ${varname})
|
|
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
|
|
endfunction(check_working_cxx_atomics64)
|
|
|
|
|
|
# This isn't necessary on MSVC, so avoid command-line switch annoyance
|
|
# by only running on GCC-like hosts.
|
|
if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
|
|
# First check if atomics work without the library.
|
|
check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB)
|
|
# If not, check if the library exists, and atomics work with it.
|
|
if(NOT HAVE_CXX_ATOMICS_WITHOUT_LIB)
|
|
check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC)
|
|
if( HAVE_LIBATOMIC )
|
|
list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
|
|
check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB)
|
|
if (NOT HAVE_CXX_ATOMICS_WITH_LIB)
|
|
message(FATAL_ERROR "Host compiler must support std::atomic!")
|
|
endif()
|
|
else()
|
|
message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
|
|
endif()
|
|
endif()
|
|
endif()
|
|
|
|
# Check for 64 bit atomic operations.
|
|
if(MSVC)
|
|
set(HAVE_CXX_ATOMICS64_WITHOUT_LIB True)
|
|
else()
|
|
check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITHOUT_LIB)
|
|
endif()
|
|
|
|
# If not, check if the library exists, and atomics work with it.
|
|
if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
|
|
check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64)
|
|
if(HAVE_CXX_LIBATOMICS64)
|
|
list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
|
|
check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB)
|
|
if (NOT HAVE_CXX_ATOMICS64_WITH_LIB)
|
|
message(FATAL_ERROR "Host compiler must support std::atomic!")
|
|
endif()
|
|
else()
|
|
message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
|
|
endif()
|
|
endif()
|
|
|
|
## TODO: This define is only used for the legacy atomic operations in
|
|
## llvm's Atomic.h, which should be replaced. Other code simply
|
|
## assumes C++11 <atomic> works.
|
|
CHECK_CXX_SOURCE_COMPILES("
|
|
#ifdef _MSC_VER
|
|
#include <windows.h>
|
|
#endif
|
|
int main() {
|
|
#ifdef _MSC_VER
|
|
volatile LONG val = 1;
|
|
MemoryBarrier();
|
|
InterlockedCompareExchange(&val, 0, 1);
|
|
InterlockedIncrement(&val);
|
|
InterlockedDecrement(&val);
|
|
#else
|
|
volatile unsigned long val = 1;
|
|
__sync_synchronize();
|
|
__sync_val_compare_and_swap(&val, 1, 0);
|
|
__sync_add_and_fetch(&val, 1);
|
|
__sync_sub_and_fetch(&val, 1);
|
|
#endif
|
|
return 0;
|
|
}
|
|
" LLVM_HAS_ATOMICS)
|
|
|
|
if( NOT LLVM_HAS_ATOMICS )
|
|
message(STATUS "Warning: LLVM will be built thread-unsafe because atomic builtins are missing")
|
|
endif()
|