From 174ff71839038b1443f4116b9bad85a48fe3935d Mon Sep 17 00:00:00 2001
From: Michal Gorny <mgorny@gentoo.org>
Date: Mon, 9 Jan 2017 23:41:38 +0000
Subject: [PATCH] [cmake] Obtain LLVM_CMAKE_PATH from llvm-config if available

Use the new --cmakedir option to obtain LLVM_CMAKE_PATH straight from
llvm-config. Fallback to local reconstruction if llvm-config does not
support this option.



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291508 91177308-0d34-0410-b5e6-96231b3b80d8
---
 cmake/Modules/HandleOutOfTreeLLVM.cmake | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/cmake/Modules/HandleOutOfTreeLLVM.cmake b/cmake/Modules/HandleOutOfTreeLLVM.cmake
index c77214324..7fee839d2 100644
--- a/cmake/Modules/HandleOutOfTreeLLVM.cmake
+++ b/cmake/Modules/HandleOutOfTreeLLVM.cmake
@@ -38,7 +38,18 @@ 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}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
+
+    # --cmakedir is supported since llvm r291218 (4.0 release)
+    execute_process(
+      COMMAND ${LLVM_CONFIG_PATH} --cmakedir
+      RESULT_VARIABLE HAD_ERROR
+      OUTPUT_VARIABLE CONFIG_OUTPUT)
+    if(NOT HAD_ERROR)
+      string(STRIP "${CONFIG_OUTPUT}" LLVM_CMAKE_PATH)
+    else()
+      set(LLVM_CMAKE_PATH
+          "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
+    endif()
   else()
     set(LLVM_FOUND OFF)
     message(WARNING "UNSUPPORTED LIBCXX CONFIGURATION DETECTED: "