Updated to Clang 3.5a.

Change-Id: I8127eb568f674c2e72635b639a3295381fe8af82
diff --git a/runtime/CMakeLists.txt b/runtime/CMakeLists.txt
index 68ee266..dc14541 100644
--- a/runtime/CMakeLists.txt
+++ b/runtime/CMakeLists.txt
@@ -1,7 +1,8 @@
 # TODO: Set the install directory.
 
+include(ExternalProject)
+
 set(known_subdirs
-  "compiler-rt"
   "libcxx"
   )
 
@@ -10,3 +11,98 @@
     add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${dir})
   endif()
 endforeach()
+
+function(get_ext_project_build_command out_var target)
+  if (CMAKE_GENERATOR MATCHES "Make")
+    # Use special command for Makefiles to support parallelism.
+    set(${out_var} "$(MAKE)" "${target}" PARENT_SCOPE)
+  else()
+    set(${out_var} ${CMAKE_COMMAND} --build . --target ${target}
+                                    --config $<CONFIGURATION> PARENT_SCOPE)
+  endif()
+endfunction()
+
+set(COMPILER_RT_SRC_ROOT ${LLVM_MAIN_SRC_DIR}/projects/compiler-rt)
+if(LLVM_BUILD_EXTERNAL_COMPILER_RT AND EXISTS ${COMPILER_RT_SRC_ROOT}/)
+  if(CMAKE_GENERATOR MATCHES "Ninja")
+    message(FATAL_ERROR
+            "Ninja generator can't build compiler-rt as ExternalProject."
+            "Unset LLVM_BUILD_EXTERNAL_COMPILER_RT, or don't use Ninja."
+            "See http://www.cmake.org/Bug/view.php?id=14771")
+  endif()
+
+  # Add compiler-rt as an external project.
+  set(COMPILER_RT_PREFIX ${CMAKE_BINARY_DIR}/projects/compiler-rt)
+  
+  ExternalProject_Add(compiler-rt
+    PREFIX ${COMPILER_RT_PREFIX}
+    SOURCE_DIR ${COMPILER_RT_SRC_ROOT}
+    CMAKE_ARGS -DCMAKE_C_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang
+               -DCMAKE_CXX_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++
+               -DCMAKE_BUILD_TYPE=Release
+               -DLLVM_CONFIG_PATH=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-config
+               -DCOMPILER_RT_OUTPUT_DIR=${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}
+               -DCOMPILER_RT_EXEC_OUTPUT_DIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
+               -DCOMPILER_RT_INSTALL_PATH=lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}
+               -DCOMPILER_RT_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
+               -DCOMPILER_RT_ENABLE_WERROR=ON
+    INSTALL_COMMAND ""
+    STEP_TARGETS configure build
+    )
+  # Due to a bug, DEPENDS in ExternalProject_Add doesn't work
+  # in CMake 2.8.9 and 2.8.10.
+  add_dependencies(compiler-rt llvm-config clang)
+
+  # Add a custom step to always re-configure compiler-rt (in case some of its
+  # sources have changed).
+  ExternalProject_Add_Step(compiler-rt force-reconfigure
+    DEPENDERS configure
+    ALWAYS 1
+    )
+
+  ExternalProject_Add_Step(compiler-rt clobber
+    COMMAND ${CMAKE_COMMAND} -E remove_directory <BINARY_DIR>
+    COMMAND ${CMAKE_COMMAND} -E make_directory <BINARY_DIR>
+    COMMENT "Clobberring compiler-rt build directory..."
+    DEPENDERS configure
+    DEPENDS ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang
+  )
+
+  ExternalProject_Get_Property(compiler-rt BINARY_DIR)
+  set(COMPILER_RT_BINARY_DIR ${BINARY_DIR})
+
+  # Add top-level targets that build specific compiler-rt runtimes.
+  set(COMPILER_RT_RUNTIMES asan builtins dfsan lsan msan profile tsan ubsan)
+  foreach(runtime ${COMPILER_RT_RUNTIMES})
+    get_ext_project_build_command(build_runtime_cmd ${runtime})
+    add_custom_target(${runtime}
+      COMMAND ${build_runtime_cmd}
+      DEPENDS compiler-rt-configure
+      WORKING_DIRECTORY ${COMPILER_RT_BINARY_DIR}
+      VERBATIM)
+  endforeach()
+
+  # Add binaries that compiler-rt tests depend on.
+  set(COMPILER_RT_TEST_DEPENDENCIES
+    FileCheck count not llvm-nm llvm-symbolizer)
+
+  # Add top-level targets for various compiler-rt test suites.
+  set(COMPILER_RT_TEST_SUITES check-asan check-dfsan check-lsan check-msan
+    check-sanitizer check-tsan check-ubsan)
+  foreach(test_suite ${COMPILER_RT_TEST_SUITES})
+    get_ext_project_build_command(run_test_suite ${test_suite})
+    add_custom_target(${test_suite}
+      COMMAND ${run_test_suite}
+      DEPENDS compiler-rt-build ${COMPILER_RT_TEST_DEPENDENCIES}
+      WORKING_DIRECTORY ${COMPILER_RT_BINARY_DIR}
+      VERBATIM)
+  endforeach()
+
+  # Add special target to run all compiler-rt test suites.
+  get_ext_project_build_command(run_check_compiler_rt check-all)
+  add_custom_target(check-compiler-rt
+    COMMAND ${run_check_compiler_rt}
+    DEPENDS compiler-rt-build ${COMPILER_RT_TEST_DEPENDENCIES}
+    WORKING_DIRECTORY ${COMPILER_RT_BINARY_DIR}
+    VERBATIM)
+endif()