[libcxx] r260515 - Re-commit "Introduce a cmake module to figure out whether we need to link with libatomic."
Vasileios Kalintiris via cfe-commits
cfe-commits at lists.llvm.org
Thu Feb 11 07:09:56 PST 2016
Hi Hans,
Can we merge this on the release branch? It's a re-commit of D16613's patch with the an additional option (-gcc-toolchain) to the default flags, that we use in order to test support for atomics, when the user doesn't want to use the default/system GCC installation. Buildbots look good with this.
Thanks,
Vasileios
________________________________________
From: cfe-commits [cfe-commits-bounces at lists.llvm.org] on behalf of Vasileios Kalintiris via cfe-commits [cfe-commits at lists.llvm.org]
Sent: 11 February 2016 12:43
To: cfe-commits at lists.llvm.org
Subject: [libcxx] r260515 - Re-commit "Introduce a cmake module to figure out whether we need to link with libatomic."
Author: vkalintiris
Date: Thu Feb 11 06:43:04 2016
New Revision: 260515
URL: http://llvm.org/viewvc/llvm-project?rev=260515&view=rev
Log:
Re-commit "Introduce a cmake module to figure out whether we need to link with libatomic."
This re-applies commit r260235. However, this time we add -gcc-toolchain
to the compiler's flags when the user has specified the LIBCXX_GCC_TOOLCHAIN
variable.
Added:
libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake
Modified:
libcxx/trunk/cmake/config-ix.cmake
libcxx/trunk/lib/CMakeLists.txt
libcxx/trunk/test/CMakeLists.txt
libcxx/trunk/test/libcxx/test/target_info.py
libcxx/trunk/test/lit.site.cfg.in
Added: libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake?rev=260515&view=auto
==============================================================================
--- libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake (added)
+++ libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake Thu Feb 11 06:43:04 2016
@@ -0,0 +1,41 @@
+INCLUDE(CheckCXXSourceCompiles)
+
+# Sometimes linking against libatomic is required for atomic ops, if
+# the platform doesn't support lock-free atomics.
+#
+# We could modify LLVM's CheckAtomic module and have it check for 64-bit
+# atomics instead. However, we would like to avoid careless uses of 64-bit
+# atomics inside LLVM over time on 32-bit platforms.
+
+function(check_cxx_atomics varname)
+ set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+ set(CMAKE_REQUIRED_FLAGS "-std=c++11")
+ if (${LIBCXX_GCC_TOOLCHAIN})
+ set(CMAKE_REQUIRED_FLAGS "-std=c++11 --gcc-toolchain=${LIBCXX_GCC_TOOLCHAIN}")
+ endif()
+ check_cxx_source_compiles("
+#include <cstdint>
+#include <atomic>
+std::atomic<uintptr_t> x;
+std::atomic<uintmax_t> y;
+int main() {
+ return x + y;
+}
+" ${varname})
+ set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+endfunction(check_cxx_atomics)
+
+check_cxx_atomics(LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
+# If not, check if the library exists, and atomics work with it.
+if(NOT LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
+ check_library_exists(atomic __atomic_fetch_add_8 "" HAVE_LIBATOMIC)
+ if(HAVE_LIBATOMIC)
+ list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
+ check_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()
Modified: libcxx/trunk/cmake/config-ix.cmake
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/config-ix.cmake?rev=260515&r1=260514&r2=260515&view=diff
==============================================================================
--- libcxx/trunk/cmake/config-ix.cmake (original)
+++ libcxx/trunk/cmake/config-ix.cmake Thu Feb 11 06:43:04 2016
@@ -1,5 +1,6 @@
include(CheckLibraryExists)
include(CheckCXXCompilerFlag)
+include(CheckLibcxxAtomic)
# Check compiler flags
@@ -17,3 +18,7 @@ check_library_exists(c fopen "" LIBCXX_H
check_library_exists(m ccos "" LIBCXX_HAS_M_LIB)
check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)
check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXX_HAS_GCC_S_LIB)
+
+if (NOT HAVE_CXX_ATOMICS_WITHOUT_LIB)
+ set(LIBCXX_HAS_ATOMIC_LIB True)
+endif()
Modified: libcxx/trunk/lib/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/lib/CMakeLists.txt?rev=260515&r1=260514&r2=260515&view=diff
==============================================================================
--- libcxx/trunk/lib/CMakeLists.txt (original)
+++ libcxx/trunk/lib/CMakeLists.txt Thu Feb 11 06:43:04 2016
@@ -79,6 +79,7 @@ add_library_flags_if(LIBCXX_HAS_C_LIB c)
add_library_flags_if(LIBCXX_HAS_M_LIB m)
add_library_flags_if(LIBCXX_HAS_RT_LIB rt)
add_library_flags_if(LIBCXX_HAS_GCC_S_LIB gcc_s)
+add_library_flags_if(LIBCXX_HAS_ATOMIC_LIB atomic)
# Setup flags.
add_flags_if_supported(-fPIC)
Modified: libcxx/trunk/test/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/CMakeLists.txt?rev=260515&r1=260514&r2=260515&view=diff
==============================================================================
--- libcxx/trunk/test/CMakeLists.txt (original)
+++ libcxx/trunk/test/CMakeLists.txt Thu Feb 11 06:43:04 2016
@@ -15,6 +15,7 @@ pythonize_bool(LIBCXX_ENABLE_SHARED)
pythonize_bool(LIBCXX_BUILD_32_BITS)
pythonize_bool(LIBCXX_GENERATE_COVERAGE)
pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)
+pythonize_bool(LIBCXX_HAS_ATOMIC_LIB)
# The tests shouldn't link to any ABI library when it has been linked into
# libc++ statically or via a linker script.
Modified: libcxx/trunk/test/libcxx/test/target_info.py
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/test/target_info.py?rev=260515&r1=260514&r2=260515&view=diff
==============================================================================
--- libcxx/trunk/test/libcxx/test/target_info.py (original)
+++ libcxx/trunk/test/libcxx/test/target_info.py Thu Feb 11 06:43:04 2016
@@ -172,6 +172,9 @@ class LinuxLocalTI(DefaultTargetInfo):
flags += ['-lunwind', '-ldl']
else:
flags += ['-lgcc_s', '-lgcc']
+ use_libatomic = self.full_config.get_lit_bool('use_libatomic', False)
+ if use_libatomic:
+ flags += ['-latomic']
san = self.full_config.get_lit_conf('use_sanitizer', '').strip()
if san:
# The libraries and their order are taken from the
Modified: libcxx/trunk/test/lit.site.cfg.in
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/lit.site.cfg.in?rev=260515&r1=260514&r2=260515&view=diff
==============================================================================
--- libcxx/trunk/test/lit.site.cfg.in (original)
+++ libcxx/trunk/test/lit.site.cfg.in Thu Feb 11 06:43:04 2016
@@ -20,6 +20,7 @@ config.generate_coverage = "@LIBC
config.target_info = "@LIBCXX_TARGET_INFO@"
config.executor = "@LIBCXX_EXECUTOR@"
config.llvm_unwinder = "@LIBCXXABI_USE_LLVM_UNWINDER@"
+config.use_libatomic = "@LIBCXX_HAS_ATOMIC_LIB@"
# Let the main config do the real work.
lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")
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