4 files changed, 71 insertions, 11 deletions
diff --git a/cmake/Modules/CheckLibcxxAtomic.cmake b/cmake/Modules/CheckLibcxxAtomic.cmake
new file mode 100644
index 000000000000..4ff343236fea
--- /dev/null
+++ b/cmake/Modules/CheckLibcxxAtomic.cmake
@@ -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 -nostdinc++ -isystem ${LIBCXX_SOURCE_DIR}/include")
+  if (${LIBCXX_GCC_TOOLCHAIN})
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --gcc-toolchain=${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 ${OLD_CMAKE_REQUIRED_FLAGS})
+endfunction(check_cxx_atomics)
+
+check_cxx_atomics(LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB)
+check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
+# If not, check if the library exists, and atomics work with it.
+if(NOT LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB)
+  if(LIBCXX_HAS_ATOMIC_LIB)
+    list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
+    check_cxx_atomics(LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
+    if (NOT LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
+      message(WARNING "Host compiler must support std::atomic!")
+    endif()
+  else()
+    message(WARNING "Host compiler appears to require libatomic, but cannot find it.")
+  endif()
+endif()
diff --git a/cmake/Modules/HandleLibCXXABI.cmake b/cmake/Modules/HandleLibCXXABI.cmake
index d9c652d87bad..c655adff718e 100644
--- a/cmake/Modules/HandleLibCXXABI.cmake
+++ b/cmake/Modules/HandleLibCXXABI.cmake
@@ -21,9 +21,11 @@ macro(setup_abi_lib abidefines abilib abifiles abidirs)
     CACHE PATH
     "Paths to C++ ABI header directories separated by ';'." FORCE
     )
-
+  set(LIBCXX_CXX_ABI_LIBRARY_PATH "${LIBCXX_CXX_ABI_LIBRARY_PATH}"
+    CACHE PATH
+    "Paths to C++ ABI library directory"
+    )
   set(LIBCXX_CXX_ABI_LIBRARY ${abilib})
-
   set(LIBCXX_ABILIB_FILES ${abifiles})
 
   file(MAKE_DIRECTORY "${CMAKE_BINARY_DIR}/include")
diff --git a/cmake/Modules/HandleLibcxxFlags.cmake b/cmake/Modules/HandleLibcxxFlags.cmake
index bb886fa8a01f..325c1bdf7bcb 100644
--- a/cmake/Modules/HandleLibcxxFlags.cmake
+++ b/cmake/Modules/HandleLibcxxFlags.cmake
@@ -35,6 +35,11 @@ macro(remove_flags)
   endforeach()
 endmacro(remove_flags)
 
+macro(check_flag_supported flag)
+    mangle_name("${flag}" flagname)
+    check_cxx_compiler_flag("${flag}" "LIBCXX_SUPPORTS_${flagname}_FLAG")
+endmacro()
+
 # Add a macro definition if condition is true.
 macro(define_if condition def)
   if (${condition})
@@ -71,6 +76,26 @@ macro(config_define value def)
   set(LIBCXX_NEEDS_SITE_CONFIG ON)
 endmacro()
 
+# Add a list of flags to all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS',
+# 'LIBCXX_COMPILE_FLAGS' and 'LIBCXX_LINK_FLAGS'.
+macro(add_target_flags)
+  foreach(value ${ARGN})
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${value}")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${value}")
+    list(APPEND LIBCXX_COMPILE_FLAGS ${value})
+    list(APPEND LIBCXX_LINK_FLAGS ${value})
+  endforeach()
+endmacro()
+
+# If the specified 'condition' is true then add a list of flags to
+# all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS', 'LIBCXX_COMPILE_FLAGS'
+# and 'LIBCXX_LINK_FLAGS'.
+macro(add_target_flags_if condition)
+  if (${condition})
+    add_target_flags(${ARGN})
+  endif()
+endmacro()
+
 # Add a specified list of flags to both 'LIBCXX_COMPILE_FLAGS' and
 # 'LIBCXX_LINK_FLAGS'.
 macro(add_flags)
diff --git a/cmake/Modules/HandleOutOfTreeLLVM.cmake b/cmake/Modules/HandleOutOfTreeLLVM.cmake
index 6215be7f586a..9c5dd8109261 100644
--- a/cmake/Modules/HandleOutOfTreeLLVM.cmake
+++ b/cmake/Modules/HandleOutOfTreeLLVM.cmake
@@ -35,7 +35,7 @@ macro(find_llvm_parts)
     set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
     set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
     set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
-    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/share/llvm/cmake")
+    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
   else()
     set(LLVM_FOUND OFF)
     return()
@@ -93,14 +93,6 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   endif()
   set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
 
-  # Make sure we can use the console pool for recent cmake and ninja > 1.5
-  # Needed for add_lit_testsuite
-  if(CMAKE_VERSION VERSION_LESS 3.1.20141117)
-    set(cmake_3_2_USES_TERMINAL)
-  else()
-    set(cmake_3_2_USES_TERMINAL USES_TERMINAL)
-  endif()
-
   # Required doc configuration
   if (LLVM_ENABLE_SPHINX)
     message(STATUS "Sphinx enabled.")