Fix gtest and LLVM builds with ABI flag setting (#2019)

* fix gtest abi build

* fix llvm build with abi flag

* remove debug

* add check for conflicting flags in cmake

CMakeLists.txt

@@ -74,6 +74,10 @@ if($ENV{NGRAPH_USE_PREBUILT_LLVM})
     set(NGRAPH_USE_PREBUILT_LLVM TRUE)
 endif()
 
+if (DEFINED NGRAPH_USE_CXX_ABI AND NGRAPH_USE_PREBUILT_LLVM)
+    message(FATAL_ERROR "Unable to use NGRAPH_USE_PREBUILT_LLVM with NGRAPH_USE_CXX_ABI")
+endif()
+
 # These variables are undocumented but useful.
 set(CMAKE_DISABLE_SOURCE_CHANGES ON)
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)

cmake/external_gtest.cmake

@@ -24,6 +24,13 @@ include(ExternalProject)
 SET(GTEST_GIT_REPO_URL https://github.com/google/googletest.git)
 SET(GTEST_GIT_LABEL release-1.8.1)
 
+set(COMPILE_FLAGS -fPIC)
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    if (DEFINED NGRAPH_USE_CXX_ABI)
+        set(COMPILE_FLAGS "${COMPILE_FLAGS} -D_GLIBCXX_USE_CXX11_ABI=${NGRAPH_USE_CXX_ABI}")
+    endif()    
+endif()
+
 # The 'BUILD_BYPRODUCTS' argument was introduced in CMake 3.2.
 if (${CMAKE_VERSION} VERSION_LESS 3.2)
     ExternalProject_Add(
@@ -36,7 +43,7 @@ if (${CMAKE_VERSION} VERSION_LESS 3.2)
         UPDATE_COMMAND ""
         CMAKE_ARGS -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
                    -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
-                   -DCMAKE_CXX_FLAGS="-fPIC"
+                   -DCMAKE_CXX_FLAGS=${COMPILE_FLAGS}
         TMP_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/tmp"
         STAMP_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/stamp"
         DOWNLOAD_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/download"
@@ -56,7 +63,7 @@ else()
         UPDATE_COMMAND ""
         CMAKE_ARGS -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
                    -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
-                   -DCMAKE_CXX_FLAGS="-fPIC"
+                   -DCMAKE_CXX_FLAGS=${COMPILE_FLAGS}
         TMP_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/tmp"
         STAMP_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/stamp"
         DOWNLOAD_DIR "${EXTERNAL_PROJECTS_ROOT}/gtest/download"

cmake/external_llvm.cmake

@@ -16,6 +16,12 @@
 
 include(ExternalProject)
 
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    if (DEFINED NGRAPH_USE_CXX_ABI)
+        set(COMPILE_FLAGS "-D_GLIBCXX_USE_CXX11_ABI=${NGRAPH_USE_CXX_ABI}")
+    endif()    
+endif()
+
 ExternalProject_Add(
     ext_clang
     GIT_REPOSITORY https://github.com/llvm-mirror/clang.git
@@ -70,6 +76,7 @@ ExternalProject_Add(
     CMAKE_ARGS -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                 -DCMAKE_ASM_COMPILER=${LLVM_CMAKE_ASM_COMPILER}
                 -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+                -DCMAKE_CXX_FLAGS=${COMPILE_FLAGS}
                 -DCMAKE_INSTALL_PREFIX=${EXTERNAL_PROJECTS_ROOT}/llvm
                 -DCMAKE_BUILD_TYPE=Release
                 -DLLVM_ENABLE_ASSERTIONS=OFF