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author | Sagar Thakur <sagar.thakur@imgtec.com> | 2016-06-23 06:39:35 +0000 |
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committer | Sagar Thakur <sagar.thakur@imgtec.com> | 2016-06-23 06:39:35 +0000 |
commit | 7c2609ae10e8875709ba5196da52303640de7674 (patch) | |
tree | 9e2c607311d108d66b2f1c25a6865bcbdfe56770 /cmake | |
parent | 5ec082bfb3f831e565668935946f3bbfc4788b10 (diff) |
[LLVM][MIPS] Introduce 64 bit atomic check in CheckAtomic.cmake
Patch by Nitesh Jain.
Summary: On some target like MIPS32 we need to explicitly link atomic library for 64 bit atomic operations. This module then can be used in LLDB (http://reviews.llvm.org/D20464) or Libcxx (http://reviews.llvm.org/D16613) for explicitly link to atomic library.
Reviewers: chandlerc, beanz
Differential: reviews.llvm.org/D20896
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273534 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'cmake')
-rw-r--r-- | cmake/modules/CheckAtomic.cmake | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/cmake/modules/CheckAtomic.cmake b/cmake/modules/CheckAtomic.cmake index 551de6ade84..dcf021b8fdd 100644 --- a/cmake/modules/CheckAtomic.cmake +++ b/cmake/modules/CheckAtomic.cmake @@ -18,6 +18,22 @@ int main() { 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) @@ -38,6 +54,27 @@ if (LLVM_COMPILER_IS_GCC_COMPATIBLE) 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. |