From f7d715248dc6e5e8224d1f161d61e551df111377 Mon Sep 17 00:00:00 2001
From: Gil Pitney <gil.pitney@linaro.org>
Date: Thu, 9 Jul 2015 00:37:33 +0000
Subject: Implemented CMake check for opencl-headers minium version 1.2
 installed

Previously, it was assumed the OpenCL headers version 1.2 were installed, and
if not, the build failed.

Now CMake will check this and error out before the build.

OpenCL header versions greater than 1.2 should also be acceptable.

Signed-off-by: Gil Pitney <gil.pitney@linaro.org>
---
 CMakeLists.txt                        |  7 ++++++-
 cmake/modules/FindOpenCLHeaders.cmake | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 cmake/modules/FindOpenCLHeaders.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8a415d2..3179116 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -75,6 +75,11 @@ SET(CMAKE_VERBOSE_MAKEFILE TRUE)
 # Do not use system installed versions
 Find_Package(LLVM REQUIRED)
 Find_Package(Clang REQUIRED)
+# Shamrock build requires headers in standard location, result of
+#   apt-get install opencl-headers (eg: on Ubuntu)
+if (SHAMROCK_BUILD)
+    Find_Package(OpenCLHeaders 1.2 EXACT REQUIRED)
+endif()
 
 # OpenCL requires boost headers. If boost is installed to some directory
 # other than /usr/include then define BOOST_INCLUDEDIR as below:
@@ -141,8 +146,8 @@ ENDIF (BUILD_TESTS)
 endif()
 
 # install OCL builtin and extension headers in opencl-headers package installation directory.
-# TODO: We should require that the Khronos OpenCL headers have already been installed there.
 if (SHAMROCK_BUILD)
+# TODO: Android may not have a /usr/include directory.
 #install(DIRECTORY include DESTINATION /usr ${OCL_DPERMS})
 #install(DIRECTORY include/CL DESTINATION /usr/include ${OCL_DPERMS})
 install(FILES include/clc.h DESTINATION /usr/include/CL )
diff --git a/cmake/modules/FindOpenCLHeaders.cmake b/cmake/modules/FindOpenCLHeaders.cmake
new file mode 100644
index 0000000..6fafc79
--- /dev/null
+++ b/cmake/modules/FindOpenCLHeaders.cmake
@@ -0,0 +1,32 @@
+# FindOCLHeaders
+#
+# If successful, will define::
+#
+#   OCL_INCLUDE_DIR    - Set to where CL/cl.h was found
+#   OCL_VERSION_STRING - Version of the OpenCL Headers "[Major].[minor]"
+#
+
+include(CheckSymbolExists)
+find_path(OCL_INCLUDE_DIR NAMES CL/cl.h  PATHS /usr/include )
+
+set(REQUIRED_VERSION "1_2")
+if (${OCL_INCLUDE_DIR} STREQUAL "OCL_INCLUDE_DIR-NOTFOUND")
+    message(STATUS "Please install opencl-headers package for version ${REQUIRED_VERSION}")
+    message(FATAL_ERROR "ERROR: Unable to find installed OpenCL Headers")
+endif()
+
+set(CMAKE_REQUIRED_INCLUDES "${OpenCL_INCLUDE_DIR}")
+
+CHECK_SYMBOL_EXISTS(CL_VERSION_${REQUIRED_VERSION}  "${OCL_INCLUDE_DIR}/CL/cl.h"
+        OPENCL_VERSION_${VERSION})
+
+if(OPENCL_VERSION_${VERSION})
+    string(REPLACE "_" "." REQUIRED_VERSION "${REQUIRED_VERSION}")
+    set(OCL_VERSION_STRING ${REQUIRED_VERSION} )
+endif()
+
+MESSAGE(STATUS "OpenCL Headers: Path: ${OCL_INCLUDE_DIR}; Version: ${OCL_VERSION_STRING}")
+
+if ("${OCL_VERSION_STRING}" STREQUAL "" OR NOT "${OCL_VERSION_STRING}" STREQUAL "${REQUIRED_VERSION}")
+    message(FATAL_ERROR  "ERROR: expected OpenCL Headers version ${REQUIRED_VERSION}")
+endif()
-- 
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