Enable GMock and improve gtest configuration (#2976)

Our current cmake/gtest.cmake file does not enable gmock. Gmock is needed for matchers that are needed for more readable unit tests. This PR enables gmock and does a little cleanup in gtest.cmake:

* Enable BUILD_GMOCK by default (was previously disabled)
* Patch gtest-src/googlemock/CMakeLists.txt for broken include path.
* Add configuration to gmock if the target is used.

No other changes in this PR, but I've verified I can use gmock matchers correctly once I include these changes in other code.

[ROCm/composable_kernel commit: fc2a121c44]

cmake/gtest.cmake

@@ -12,6 +12,17 @@ FetchContent_Declare(
     GIT_TAG f8d7d77c06936315286eb55f8de22cd23c188571
 )
 
+FetchContent_Populate(GTest)
+
+# Patch googlemock/CMakeLists.txt to fix invalid include path
+set(GMOCK_CMAKE "${gtest_SOURCE_DIR}/googlemock/CMakeLists.txt")
+file(READ "${GMOCK_CMAKE}" GMOCK_CMAKE_CONTENT)
+string(REPLACE [[gtest_SOURCE_DIR}/include]]
+               [[gtest_SOURCE_DIR}/googletest/include]]
+               GMOCK_CMAKE_CONTENT
+               "${GMOCK_CMAKE_CONTENT}")
+file(WRITE "${GMOCK_CMAKE}" "${GMOCK_CMAKE_CONTENT}")
+
 # Suppress ROCMChecks WARNING on GoogleTests
 set(ROCM_DISABLE_CHECKS FALSE)
 macro(rocm_check_toolchain_var var access value list_file)
@@ -24,7 +35,7 @@ if(WIN32)
     set(gtest_force_shared_crt ON CACHE_INTERNAL "")
 endif()
 
-set(BUILD_GMOCK OFF CACHE INTERNAL "")
+set(BUILD_GMOCK ON CACHE INTERNAL "")
 set(INSTALL_GTEST OFF CACHE INTERNAL "")
 
 # Store the current value of BUILD_SHARED_LIBS
@@ -32,15 +43,12 @@ set(__build_shared_libs ${BUILD_SHARED_LIBS})
 set(BUILD_SHARED_LIBS OFF CACHE INTERNAL "")
 
 set(ROCM_DISABLE_CHECKS TRUE)
-FetchContent_MakeAvailable(GTest)
+add_subdirectory(${gtest_SOURCE_DIR} ${gtest_BINARY_DIR})
 set(ROCM_DISABLE_CHECKS FALSE)
 
 # Restore the old value of BUILD_SHARED_LIBS
 set(BUILD_SHARED_LIBS ${__build_shared_libs} CACHE BOOL "Type of libraries to build" FORCE)
 
-set(BUILD_GMOCK OFF CACHE INTERNAL "")
-set(INSTALL_GTEST OFF CACHE INTERNAL "")
-
 set(GTEST_CXX_FLAGS
      -Wno-undef
      -Wno-reserved-identifier
@@ -71,3 +79,12 @@ target_compile_options(gtest_main PRIVATE ${GTEST_CXX_FLAGS})
 target_compile_definitions(gtest PRIVATE GTEST_HAS_SEH=0)
 target_compile_definitions(gtest_main PRIVATE GTEST_HAS_SEH=0)
 
+if(TARGET gmock)
+    target_compile_options(gmock PRIVATE ${GTEST_CXX_FLAGS})
+    target_compile_definitions(gmock PRIVATE GTEST_HAS_SEH=0)
+endif()
+
+if(TARGET gmock_main)
+    target_compile_options(gmock_main PRIVATE ${GTEST_CXX_FLAGS})
+    target_compile_definitions(gmock_main PRIVATE GTEST_HAS_SEH=0)
+endif()