krytarowski created this revision.
krytarowski added reviewers: labath, zturner.
krytarowski added subscribers: lldb-commits, llvm-commits, joerg.
krytarowski set the repository for this revision to rL LLVM.
LLVM doesn't install "CheckAtomic" cmake file, so add it locally.
Bump required CMake version to 3.4.3 (sync with the master CMakeLists.txt)
This fixes build on NetBSD.
Repository:
rL LLVM
https://reviews.llvm.org/D22999
Files:
cmake/modules/CheckAtomic.cmake
cmake/modules/LLDBStandalone.cmake
Index: cmake/modules/LLDBStandalone.cmake
===================================================================
--- cmake/modules/LLDBStandalone.cmake
+++ cmake/modules/LLDBStandalone.cmake
@@ -2,7 +2,7 @@
# standalone project, using LLVM as an external library:
if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
project(lldb)
- cmake_minimum_required(VERSION 2.8.12.2)
+ cmake_minimum_required(VERSION 3.4.3)
if (POLICY CMP0022)
cmake_policy(SET CMP0022 NEW) # automatic when 2.8.12 is required
@@ -86,7 +86,7 @@
include(AddLLVM)
include(HandleLLVMOptions)
- include(CheckAtomic)
+ include(cmake/modules/CheckAtomic.cmake)
if (PYTHON_EXECUTABLE STREQUAL "")
set(Python_ADDITIONAL_VERSIONS 3.5 3.4 3.3 3.2 3.1 3.0 2.7 2.6 2.5)
Index: cmake/modules/CheckAtomic.cmake
===================================================================
--- /dev/null
+++ cmake/modules/CheckAtomic.cmake
@@ -0,0 +1,106 @@
+# atomic builtins are required for threading support.
+
+INCLUDE(CheckCXXSourceCompiles)
+
+# 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 "-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 <Intrin.h> /* Workaround for PR19898. */
+#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()
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
