Use own benchmark and not any system pre-built ones:

Summary:
(1) use the cmake files of the corresponding libs
(2) allow static linkage of gtest and gbenchmark.
(3) Helps removing the temp solution in #1112

We are yet to disable the installation of the benchmark library, and I have an open pull request at https://github.com/google/benchmark/pull/463 - once it is merged I will do submodule update.

cc lukeyeager pietern who had this issue before - hopefully this makes the solution cleaner.
Closes https://github.com/caffe2/caffe2/pull/1358

Differential Revision: D6111404

Pulled By: Yangqing

fbshipit-source-id: 17468d32cef27f96e9445d119eb869c9c7913118

CMakeLists.txt

@@ -9,12 +9,6 @@ set(CAFFE2_VERSION_PATCH 1)
 set(CAFFE2_VERSION
     "${CAFFE2_VERSION_MAJOR}.${CAFFE2_VERSION_MINOR}.${CAFFE2_VERSION_PATCH}")
 
-# ---[ Do not search cmake install prefix. See the following link for details:
-# https://github.com/caffe2/caffe2/commit/251d2d0c521c781276eea3748d92fc92e5dbceab
-message(STATUS "Setting CMAKE_FIND_NO_INSTALL_PREFIX")
-set(CMAKE_FIND_NO_INSTALL_PREFIX TRUE)
-
-
 # ---[ Options.
 # Note to developers: if you add an option below, make sure you also add it to
 # cmake/Summary.cmake so that the summary prints out the option values.

caffe2/binaries/CMakeLists.txt

@@ -13,6 +13,12 @@ if (USE_CUDA)
   caffe2_binary_target("inspect_gpus.cc")
   target_link_libraries(inspect_gpus ${CUDA_LIBRARIES})
   caffe2_binary_target("print_core_object_sizes.cc")
+
+  if (BUILD_TEST)
+    # Core overhead benchmark
+    caffe2_binary_target("core_overhead_benchmark.cc")
+    target_link_libraries(core_overhead_benchmark benchmark)
+  endif()
 endif()
 
 if (USE_ZMQ)

cmake/Dependencies.cmake

@@ -114,17 +114,28 @@ endif()
 
 # ---[ Googletest and benchmark
 if(BUILD_TEST)
+  set(TEMP_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS})
+  # We will build gtest as static libs and embed it directly into the binary.
+  set(BUILD_SHARED_LIBS OFF)
+  # For gtest, we will simply embed it into our test binaries, so we won't
+  # need to install it.
+  set(BUILD_GTEST ON)
+  set(INSTALL_GTEST OFF)
+  # We currently don't need gmock right now.
+  set(BUILD_GMOCK OFF)
   add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/googletest)
   caffe2_include_directories(${PROJECT_SOURCE_DIR}/third_party/googletest/googletest/include)
 
-  find_package(Benchmark)
-  if(Benchmark_FOUND)
-    list(APPEND Caffe2_DEPENDENCY_LIBS ${Benchmark_LIBRARIES})
-    caffe2_include_directories(${Benchmark_INCLUDE_DIRS})
-  else()
-    add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/benchmark)
-    caffe2_include_directories(${PROJECT_SOURCE_DIR}/third_party/benchmark/include)
-  endif()
+  # We will not need to test benchmark lib itself.
+  set(BENCHMARK_ENABLE_TESTING OFF)
+  # We will not need to install benchmark. This is pending 
+  # https://github.com/google/benchmark/pull/463
+  set(INSTALL_BENCHMARK OFF)
+  add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/benchmark)
+  caffe2_include_directories(${PROJECT_SOURCE_DIR}/third_party/benchmark/include)
+
+  # Recover the build shared libs option.
+  set(BUILD_SHARED_LIBS ${TEMP_BUILD_SHARED_LIBS})
 endif()
 
 # ---[ LMDB