diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6659e53..785c5b5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -683,6 +683,14 @@ if( LLVM_INCLUDE_EXAMPLES )
 endif()
 
 if( LLVM_INCLUDE_TESTS )
+  if(EXISTS ${LLVM_MAIN_SRC_DIR}/projects/test-suite AND TARGET clang)
+    include(LLVMExternalProjectUtils)
+    llvm_ExternalProject_Add(test-suite ${LLVM_MAIN_SRC_DIR}/projects/test-suite
+      USE_CLANG
+      EXCLUDE_FROM_ALL
+      NO_INSTALL
+      FORCE_CLEAN_DEPENDS clang)
+  endif()
   add_subdirectory(test)
   add_subdirectory(unittests)
   if (MSVC)
diff --git a/cmake/modules/LLVMExternalProjectUtils.cmake b/cmake/modules/LLVMExternalProjectUtils.cmake
new file mode 100644
index 0000000..31745c7
--- /dev/null
+++ b/cmake/modules/LLVMExternalProjectUtils.cmake
@@ -0,0 +1,166 @@
+include(ExternalProject)
+
+# llvm_ExternalProject_BuildCmd(out_var target)
+#   Utility function for constructing command lines for external project targets
+function(llvm_ExternalProject_BuildCmd out_var target)
+  if (CMAKE_GENERATOR MATCHES "Make")
+    # Use special command for Makefiles to support parallelism.
+    set(${out_var} "$(MAKE)" "${target}" PARENT_SCOPE)
+  else()
+    set(${out_var} ${CMAKE_COMMAND} --build . --target ${target}
+                                    --config $<CONFIGURATION> PARENT_SCOPE)
+  endif()
+endfunction()
+
+# llvm_ExternalProject_Add(name source_dir ...
+#   USE_CLANG
+#     Use just-built clang
+#   EXCLUDE_FROM_ALL
+#     Exclude this project from the all target
+#   NO_INSTALL
+#     Don't generate install targets for this project
+#   CMAKE_ARGS arguments...
+#     Optional cmake arguments to pass when configuring the project
+#   FORCE_CLEAN_DEPENDS targets...
+#     Targets that require full rebuilds of this project
+#   DEPENDS targets...
+#     Targets that this project depends on
+#   EXTRA_TARGETS targets...
+#     Extra targets in the subproject to generate targets for
+#   )
+function(llvm_ExternalProject_Add name source_dir)
+  cmake_parse_arguments(ARG "USE_CLANG;EXCLUDE_FROM_ALL;NO_INSTALL"
+    "SOURCE_DIR"
+    "CMAKE_ARGS;FORCE_CLEAN_DEPENDS;DEPENDS;EXTRA_TARGETS" ${ARGN})
+  canonicalize_tool_name(${name} nameCanon)
+
+  if(CMAKE_VERSION VERSION_GREATER 3.1.0)
+    set(cmake_3_1_EXCLUDE_FROM_ALL EXCLUDE_FROM_ALL 1)
+  endif()
+
+  if(CMAKE_VERSION VERSION_GREATER 3.3.20150708)
+    set(cmake_3_4_USES_TERMINAL_OPTIONS
+      USES_TERMINAL_CONFIGURE 1
+      USES_TERMINAL_BUILD 1
+      USES_TERMINAL_INSTALL 1
+      )
+    set(cmake_3_4_USES_TERMINAL USES_TERMINAL 1)
+  endif()
+
+  if(CMAKE_VERSION VERSION_GREATER 3.1.20141116)
+    set(cmake_3_2_USES_TERMINAL USES_TERMINAL)
+  endif()
+
+  set(STAMP_DIR ${CMAKE_CURRENT_BINARY_DIR}/${name}-stamps/)
+  set(BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${name}-bins/)
+
+  add_custom_target(${name}-clear
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${BINARY_DIR}
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${STAMP_DIR}
+    COMMENT "Clobberring ${name} build and stamp directories"
+    ${cmake_3_2_USES_TERMINAL}
+    )
+
+  # Find all variables that start with COMPILER_RT and populate a variable with
+  # them.
+  get_cmake_property(variableNames VARIABLES)
+  foreach(varaibleName ${variableNames})
+    if(${varaibleName} MATCHES "^${nameCanon}")
+      list(APPEND PASSTHROUGH_VARIABLES
+        -D${varaibleName}=${${varaibleName}})
+    endif()
+  endforeach()
+
+  if(ARG_USE_CLANG)
+    if(TARGET clang)
+      set(compiler_args -DCMAKE_C_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang
+                        -DCMAKE_CXX_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++)
+      set(ARG_DEPENDS ${ARG_DEPENDS} clang)
+    else()
+      message(FATAL_ERROR "Must have be building clang in-tree to pass USE_CLANG")
+    endif()
+    set(ARG_DEPENDS ${ARG_DEPENDS} clang)
+  endif()
+
+  add_custom_command(
+    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
+    DEPENDS ${ARG_DEPENDS}
+    COMMAND ${CMAKE_COMMAND} -E touch ${BINARY_DIR}/CMakeCache.txt
+    COMMAND ${CMAKE_COMMAND} -E touch ${STAMP_DIR}/${name}-mkdir
+    COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
+    COMMENT "Clobberring bootstrap build and stamp directories"
+    )
+
+  add_custom_target(${name}-clobber
+    DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp)
+
+  if(ARG_EXCLUDE_FROM_ALL)
+    set(exclude ${cmake_3_1_EXCLUDE_FROM_ALL})
+  endif()
+
+  ExternalProject_Add(${name}
+    DEPENDS ${ARG_DEPENDS}
+    ${name}-clobber
+    PREFIX ${CMAKE_BINARY_DIR}/projects/${name}
+    SOURCE_DIR ${source_dir}
+    STAMP_DIR ${STAMP_DIR}
+    BINARY_DIR ${BINARY_DIR}
+    ${exclude}
+    CMAKE_ARGS ${${nameCanon}_CMAKE_ARGS}
+               ${compiler_args}
+               -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
+               ${ARG_CMAKE_ARGS}
+               ${PASSTHROUGH_VARIABLES}
+    INSTALL_COMMAND ""
+    STEP_TARGETS configure build
+    ${cmake_3_4_USES_TERMINAL_OPTIONS}
+    )
+
+  if(ARG_USE_CLANG)
+    add_dependencies(${name}-configure clang)
+  endif()
+
+  if(ARG_FORCE_CLEAN_DEPENDS)
+    set(force_deps DEPENDS ${FORCE_CLEAN_DEPENDS})
+  endif()
+
+  llvm_ExternalProject_BuildCmd(run_clean clean)
+  ExternalProject_Add_Step(${name} clean
+    COMMAND ${run_clean}
+    COMMENT "Cleaning ${name}..."
+    DEPENDEES configure
+    ${force_deps}
+    WORKING_DIRECTORY ${BINARY_DIR}
+    ${cmake_3_4_USES_TERMINAL}
+    )
+  ExternalProject_Add_StepTargets(${name} clean)
+
+  if(ARG_USE_CLANG)
+    add_dependencies(${name}-clean ${name}-clobber)
+    set_target_properties(${name}-clean PROPERTIES
+      SOURCES ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp)
+  endif()
+
+  if(NOT ARG_NO_INSTALL)
+    install(CODE "execute_process\(COMMAND \${CMAKE_COMMAND} -DCMAKE_INSTALL_PREFIX=\${CMAKE_INSTALL_PREFIX} -P ${BINARY_DIR}/cmake_install.cmake \)"
+      COMPONENT ${name})
+
+    add_custom_target(install-${name}
+                      DEPENDS ${name}
+                      COMMAND "${CMAKE_COMMAND}"
+                               -DCMAKE_INSTALL_COMPONENT=${name}
+                               -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+                      ${cmake_3_2_USES_TERMINAL})
+  endif()
+
+  # Add top-level targets
+  foreach(target ${ARG_EXTRA_TARGETS})
+    llvm_ExternalProject_BuildCmd(build_runtime_cmd ${target})
+    add_custom_target(${target}
+      COMMAND ${build_runtime_cmd}
+      DEPENDS ${name}-configure
+      WORKING_DIRECTORY ${BINARY_DIR}
+      VERBATIM
+      ${cmake_3_2_USES_TERMINAL})
+  endforeach()
+endfunction()
