[cmake] Obtain LLVM_CMAKE_PATH from llvm-config

Use the new --cmakedir option to obtain LLVM_CMAKE_PATH straight from
llvm-config instead of reconstructing it locally.

Differential Revision: https://reviews.llvm.org/D26900

llvm-svn: 291495

clang/CMakeLists.txt

@@ -16,7 +16,8 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
       "--libdir"
       "--includedir"
       "--prefix"
-      "--src-root")
+      "--src-root"
+      "--cmakedir")
     execute_process(
       COMMAND ${CONFIG_COMMAND}
       RESULT_VARIABLE HAD_ERROR
@@ -41,6 +42,7 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
   list(GET CONFIG_OUTPUT 3 INCLUDE_DIR)
   list(GET CONFIG_OUTPUT 4 LLVM_OBJ_ROOT)
   list(GET CONFIG_OUTPUT 5 MAIN_SRC_DIR)
+  list(GET CONFIG_OUTPUT 6 LLVM_CMAKE_PATH)
 
   if(NOT MSVC_IDE)
     set(LLVM_ENABLE_ASSERTIONS ${ENABLE_ASSERTIONS}
@@ -58,7 +60,6 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
     NO_DEFAULT_PATH)
 
-  set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
   set(LLVMCONFIG_FILE "${LLVM_CMAKE_PATH}/LLVMConfig.cmake")
   if(EXISTS ${LLVMCONFIG_FILE})
     list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")