Make configuring CUDA support explicit

1. Stop automatically enabling OMR_OPT_CUDA. This flag must now be
   enabled by the user.
2. Only search for CUDA resources if the feature has been enabled.
3. Only search for CUDA headers, not all resources.
4. Require that the user specify where CUDA is located via the
   OMR_CUDA_HOME directory. Do not search standard paths for CUDA
   resources.

Signed-off-by: Robert Young <rwy0717@gmail.com>

CMakeLists.txt

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2017, 2019 IBM Corp. and others
+# Copyright (c) 2017, 2020 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -63,23 +63,6 @@ set(OMR_INSTALL_ARCHIVE_DIR ${CMAKE_INSTALL_LIBDIR} CACHE PATH "Installation dir
 set(OMR_INSTALL_INC_DIR ${CMAKE_INSTALL_INCLUDEDIR} CACHE PATH "Installation directory for headers")
 set(OMR_INSTALL_DATA_DIR ${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME} CACHE PATH "Installation directory for data files")
 
-###
-### CUDA Support
-###
-
-if (OMR_ENV_DATA64)
-	find_package(Threads)
-	if(Threads_FOUND)
-		# Threads mush be found before we can look for CUDA.
-		# FindCuda will error out if Threads is missing, even though CUDA itself is optional.
-		find_package(CUDA)
-	else()
-		set(CUDA_FOUND OFF CACHE BOOL "CUDA is disabled (threads not found)")
-	endif()
-else()
-	set(CUDA_FOUND OFF CACHE BOOL "CUDA is disabled")
-endif()
-
 ###
 ### Versions and stuff
 ###

buildenv/jenkins/jobs/builds/Build-linux_x86-64

@@ -34,7 +34,7 @@ pipeline {
 
                     dir('build') {
                         echo 'Configure...'
-                        sh '''cmake -Wdev -C../cmake/caches/Travis.cmake ..'''
+                        sh '''cmake -Wdev -C../cmake/caches/Travis.cmake -DOMR_OPT_CUDA=ON -DOMR_CUDA_HOME=/usr/local/cuda ..'''
 
                         echo 'Compile...'
                         sh '''make -j4'''

buildenv/jenkins/jobs/pull-requests/PullRequest-linux_x86-64

@@ -20,7 +20,7 @@ pipeline {
 
                     dir('build') {
                         echo 'Configure...'
-                        sh '''cmake -Wdev -C../cmake/caches/Travis.cmake ..''' 
+                        sh '''cmake -Wdev -C../cmake/caches/Travis.cmake -DOMR_OPT_CUDA=ON -DOMR_CUDA_HOME=/usr/local/cuda ..'''
 
                         echo 'Compile...'
                         sh '''make -j4'''

cmake/config.cmake

@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2017, 2019 IBM Corp. and others
+# Copyright (c) 2017, 2020 IBM Corp. and others
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License 2.0 which accompanies this
@@ -202,6 +202,6 @@ set(OMR_NOTIFY_POLICY_CONTROL OFF CACHE BOOL "TODO: Document")
 
 set(OMR_ENV_GCC OFF CACHE BOOL "TODO: Document")
 
-set(OMR_OPT_CUDA ${CUDA_FOUND} CACHE BOOL "Enable CUDA support in OMR")
+set(OMR_OPT_CUDA OFF CACHE BOOL "Enable CUDA support in OMR. See also: OMR_CUDA_HOME in FindOmrCuda.cmake")
 
 set(OMR_SANITIZE OFF CACHE STRING "Sanitizer selection. Only has an effect on GNU or Clang")

cmake/modules/FindOmrCuda.cmake

@@ -0,0 +1,72 @@
+###############################################################################
+# Copyright (c) 2019, 2020 IBM Corp. and others
+#
+# This program and the accompanying materials are made available under
+# the terms of the Eclipse Public License 2.0 which accompanies this
+# distribution and is available at http://eclipse.org/legal/epl-2.0
+# or the Apache License, Version 2.0 which accompanies this distribution
+# and is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# This Source Code may also be made available under the following Secondary
+# Licenses when the conditions for such availability set forth in the
+# Eclipse Public License, v. 2.0 are satisfied: GNU General Public License,
+# version 2 with the GNU Classpath Exception [1] and GNU General Public
+# License, version 2 with the OpenJDK Assembly Exception [2].
+#
+# [1] https://www.gnu.org/software/classpath/license.html
+# [2] http://openjdk.java.net/legal/assembly-exception.html
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
+#############################################################################
+
+# This module locates a minimal set of cuda headers, required by the OMR_OPT_CUDA flag.
+# This module will search for CUDA resources in only one directory. The variables tested, in order of preference, are:
+#
+# 1. The cmake variable OMR_CUDA_HOME, if set.
+# 2. The cmake variable CUDA_HOME, if set.
+# 3. The environment variable CUDA_HOME, if set.
+#
+
+include(FindPackageHandleStandardArgs)
+
+set(OMR_CUDA_HOME "NOTFOUND" CACHE PATH "Path to the CUDA SDK. Takes precedence over CUDA_HOME in OMR.")
+set(OmrCuda_INCLUDE_DIRS "OmrCuda_INCLUDE_DIRS-NOTFOUND")
+
+if(OmrCuda_FIND_REQUIRED)
+	set(error_level FATAL_ERROR)
+else()
+	set(error_level WARNING)
+endif()
+
+# Establish which directory we are searching in
+
+set(OmrCuda_SEARCH_DIR "")
+
+if(OMR_CUDA_HOME)
+	set(OmrCuda_SEARCH_DIR "${OMR_CUDA_HOME}")
+elseif(CUDA_HOME)
+	set(OmrCuda_SEARCH_DIR "${CUDA_HOME}")
+elseif(ENV{CUDA_HOME})
+	set(OmrCuda_SEARCH_DIR "$ENV{CUDA_HOME}")
+else()
+	message(${error_level} "CUDA support requested, but OMR_CUDA_HOME/CUDA_HOME are not set.")
+endif()
+
+# Try to locate the main CUDA include directory by finding cuda.h
+
+find_path(OmrCuda_INCLUDE_DIR
+	NAMES cuda.h
+	PATHS ${OmrCuda_SEARCH_DIR}
+	PATH_SUFFIXES include Headers
+	DOC "The CUDA include directory"
+	NO_DEFAULT_PATH
+)
+
+find_package_handle_standard_args(OmrCuda
+	DEFAULT_MSG
+	OmrCuda_INCLUDE_DIR
+)
+
+if(OmrCuda_FOUND)
+	set(OmrCuda_INCLUDE_DIRS "${OmrCuda_INCLUDE_DIR}")
+endif()

port/CMakeLists.txt

@@ -22,7 +22,11 @@
 
 include(OmrFindFiles)
 
-if (OMR_HOST_OS STREQUAL "zos")
+if(OMR_OPT_CUDA)
+	find_package(OmrCuda REQUIRED)
+endif()
+
+if(OMR_HOST_OS STREQUAL "zos")
 	include(OmrMetalC)
 endif()
 
@@ -44,10 +48,10 @@ target_include_directories(omrport_obj
 		$<TARGET_PROPERTY:omr_base,INTERFACE_INCLUDE_DIRECTORIES>
 )
 
-if (OMR_OPT_CUDA)
+if(OMR_OPT_CUDA)
 	target_include_directories(omrport_obj
 		PRIVATE
-			${CUDA_INCLUDE_DIRS}
+			${OmrCuda_INCLUDE_DIRS}
 	)
 endif()