Auto-detect C++ ABI version (#321)

Summary:
Looks like right now system is tune to only work with official nightly
builds/gcc-7 (i.e. hardcodes ABI 11)

Fixes pytorch/pytorch#103087

Pull Request resolved: #321

Reviewed By: kit1980

Differential Revision: D46507335

Pulled By: malfet

fbshipit-source-id: 30342aa73761da3ea9207eed621c889a49e140b9

Author: malfet

multipy/runtime/CMakeLists.txt

@@ -24,7 +24,7 @@ message(STATUS "CMAKE_BUILD_TYPE - ${CMAKE_BUILD_TYPE}" )
 set(DEPLOY_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 get_filename_component(MULTIPY_DIR ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fabi-version=11 -fno-lto -fPIC")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-lto -fPIC")
 include(${DEPLOY_DIR}/utils.cmake)
 
 add_subdirectory(interpreter)

multipy/runtime/utils.cmake

@@ -19,10 +19,26 @@ if (NOT DEFINED _GLIBCXX_USE_CXX11_ABI)
     message(FATAL_ERROR "Failed to detect ABI version")
   endif()
 endif()
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_GLIBCXX_USE_CXX11_ABI=${_GLIBCXX_USE_CXX11_ABI}")
+string(APPEND CMAKE_CXX_FLAGS " -D_GLIBCXX_USE_CXX11_ABI=${_GLIBCXX_USE_CXX11_ABI}")
 add_definitions(-D_GLIBCXX_USE_CXX11_ABI=${_GLIBCXX_USE_CXX11_ABI})
 message(STATUS "_GLIBCXX_USE_CXX11_ABI - ${_GLIBCXX_USE_CXX11_ABI}")
 
+if (NOT DEFINED _CXX_ABI_VERSION)
+  # infer the ABI setting from the installed version of PyTorch
+  execute_process(
+	  COMMAND python -c "import torch; print(torch._C._PYBIND11_BUILD_ABI[-2:])"
+	  OUTPUT_VARIABLE _CXX_ABI_VERSION
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    RESULT_VARIABLE ret
+  )
+  if(ret EQUAL "1")
+    message(WARNING "Failed to detect ABI version, reseting to 11")
+    set(_CXX_ABI_VERSION 11)
+  endif()
+endif()
+string(APPEND CMAKE_CXX_FLAGS " -fabi-version=${_CXX_ABI_VERSION}")
+message(STATUS "_CXX_ABI_VERSION - ${_CXX_ABI_VERSION}")
+
 set(Python3_FIND_STRATEGY LOCATION)
 
 find_package (Python3 COMPONENTS Interpreter Development)