Add CMake variable SHADERC_SKIP_TESTS.

Configuring with -DSHADERC_SKIP_TESTS=ON will prevent building
any tests based on gtest or gmock.

Required for cross compiling from Linux to Windows with MinGW
since it seems MinGW can't compile googletest.
See google/googletest#606

To compile on Linux targeting Windows, do this:
  cmake -DCMAKE_SYSTEM_NAME=Windows \
        -DCMAKE_C_COMPILER=i686-w64-mingw32-gcc \
        -DCMAKE_CXX_COMPILER=i686-w64-mingw32-g++ \
        -DSHADERC_SKIP_TESTS=ON \
	$SHADERC_SRC_DIR

Change-Id: I31cb0568f335debb1767b93a5f9067df6848973b

CMakeLists.txt

@@ -4,6 +4,18 @@ enable_testing()
 
 message(STATUS "Shaderc: build type is \"${CMAKE_BUILD_TYPE}\".")
 
+option(SHADERC_SKIP_TESTS
+       "Skip building unit tests based on googlemock and googletest"
+       ${SHADERC_SKIP_TESTS})
+if(NOT ${SHADERC_SKIP_TESTS})
+  set(SHADERC_ENABLE_TESTS ON)
+endif()
+if(${SHADERC_ENABLE_TESTS})
+  message(STATUS "Configuring Shaderc to build unit tests.")
+else()
+  message(STATUS "Configuring Shaderc to avoid building unit tests.")
+endif()
+
 include(cmake/setup_build.cmake)
 include(cmake/utils.cmake)
 

cmake/utils.cmake

@@ -68,34 +68,36 @@ endfunction()
 # INCLUDE_DIRS: (optional) a list of include directories to be searched
 #               for header files.
 function(shaderc_add_tests)
-  cmake_parse_arguments(PARSED_ARGS
-    ""
-    "TEST_PREFIX"
-    "TEST_NAMES;LINK_LIBS;INCLUDE_DIRS"
-    ${ARGN})
-  if (NOT PARSED_ARGS_TEST_NAMES)
-    message(FATAL_ERROR "Tests must have a target")
-  endif()
-  if (NOT PARSED_ARGS_TEST_PREFIX)
-    message(FATAL_ERROR "Tests must have a prefix")
-  endif()
-  foreach(TARGET ${PARSED_ARGS_TEST_NAMES})
-    set(TEST_NAME ${PARSED_ARGS_TEST_PREFIX}_${TARGET}_test)
-    add_executable(${TEST_NAME} src/${TARGET}_test.cc)
-    shaderc_default_compile_options(${TEST_NAME})
-    if (PARSED_ARGS_LINK_LIBS)
-      target_link_libraries(${TEST_NAME} PRIVATE
-        ${PARSED_ARGS_LINK_LIBS})
+  if(${SHADERC_ENABLE_TESTS})
+    cmake_parse_arguments(PARSED_ARGS
+      ""
+      "TEST_PREFIX"
+      "TEST_NAMES;LINK_LIBS;INCLUDE_DIRS"
+      ${ARGN})
+    if (NOT PARSED_ARGS_TEST_NAMES)
+      message(FATAL_ERROR "Tests must have a target")
     endif()
-    if (PARSED_ARGS_INCLUDE_DIRS)
-      target_include_directories(${TEST_NAME} PRIVATE
-        ${PARSED_ARGS_INCLUDE_DIRS})
+    if (NOT PARSED_ARGS_TEST_PREFIX)
+      message(FATAL_ERROR "Tests must have a prefix")
     endif()
-    shaderc_use_gmock(${TEST_NAME})
-    add_test(
-      NAME ${PARSED_ARGS_TEST_PREFIX}_${TARGET}
-      COMMAND ${TEST_NAME})
-  endforeach()
+    foreach(TARGET ${PARSED_ARGS_TEST_NAMES})
+      set(TEST_NAME ${PARSED_ARGS_TEST_PREFIX}_${TARGET}_test)
+      add_executable(${TEST_NAME} src/${TARGET}_test.cc)
+      shaderc_default_compile_options(${TEST_NAME})
+      if (PARSED_ARGS_LINK_LIBS)
+	target_link_libraries(${TEST_NAME} PRIVATE
+	  ${PARSED_ARGS_LINK_LIBS})
+      endif()
+      if (PARSED_ARGS_INCLUDE_DIRS)
+	target_include_directories(${TEST_NAME} PRIVATE
+	  ${PARSED_ARGS_INCLUDE_DIRS})
+      endif()
+      shaderc_use_gmock(${TEST_NAME})
+      add_test(
+	NAME ${PARSED_ARGS_TEST_PREFIX}_${TARGET}
+	COMMAND ${TEST_NAME})
+    endforeach()
+  endif(${SHADERC_ENABLE_TESTS})
 endfunction(shaderc_add_tests)
 
 # Finds all transitive static library dependencies of a given target

libshaderc_util/CMakeLists.txt

@@ -38,8 +38,10 @@ shaderc_add_tests(
     io
     message)
 
-target_include_directories(shaderc_util_counting_includer_test
-  PRIVATE ${glslang_SOURCE_DIR})
+if(${SHADERC_ENABLE_TESTS})
+  target_include_directories(shaderc_util_counting_includer_test
+    PRIVATE ${glslang_SOURCE_DIR})
+endif()
 
 shaderc_add_tests(
   TEST_PREFIX shaderc_util
@@ -52,7 +54,9 @@ shaderc_add_tests(
 add_custom_target(testdata COMMAND
   ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_SOURCE_DIR}/testdata/copy-to-build.cmake)
 
-add_dependencies(shaderc_util_file_finder_test testdata)
-add_dependencies(shaderc_util_io_test testdata)
+if(${SHADERC_ENABLE_TESTS})
+  add_dependencies(shaderc_util_file_finder_test testdata)
+  add_dependencies(shaderc_util_io_test testdata)
+endif()
 
 add_definitions(-DCURRENT_DIR="${CMAKE_CURRENT_BINARY_DIR}")

third_party/CMakeLists.txt

@@ -2,11 +2,14 @@
 set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS -w)
 
 # Configure third party projects.
-if (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/googletest)
-  add_subdirectory(googletest)
-endif()
-if (NOT TARGET gmock)
-  message(FATAL_ERROR "gmock was not found - required for tests")
+
+if(${SHADERC_ENABLE_TESTS})
+  if (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/googletest)
+    add_subdirectory(googletest)
+  endif()
+  if (NOT TARGET gmock)
+    message(FATAL_ERROR "gmock was not found - required for tests")
+  endif()
 endif()
 
 set(OLD_PLATFORM_TOOLSET ${CMAKE_GENERATOR_TOOLSET})