Make cmake derive Paddle version from Git tag or Git commit ID

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8)
 
 project(paddle CXX C)
-set(PADDLE_MAJOR_VERSION 0)
-set(PADDLE_MINOR_VERSION 9)
-set(PADDLE_PATCH_VERSION 0a0)
-set(PADDLE_VERSION ${PADDLE_MAJOR_VERSION}.${PADDLE_MINOR_VERSION}.${PADDLE_PATCH_VERSION})
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
 set(PROJ_ROOT ${CMAKE_SOURCE_DIR})
@@ -64,18 +60,17 @@ include(check_packages)
 include(swig)
 include(coveralls)
 
-# add PaddlePaddle version
-if(DEFINED ENV{PADDLE_VERSION})
-    add_definitions(-DPADDLE_VERSION=\"$ENV{PADDLE_VERSION}\")
+# Set PaddlePaddle version to Git tag name or Git commit ID.
+find_package(Git REQUIRED)
+execute_process(
+  COMMAND ${GIT_EXECUTABLE} describe --tags --exact-match --abbrev=0
+  WORKING_DIRECTORY ${PROJ_ROOT}
+  OUTPUT_VARIABLE GIT_TAG_NAME
+  RESULT_VARIABLE GIT_RESULT
+  ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(NOT ${GIT_RESULT})
+  set(PADDLE_VERSION ${GIT_TAG_NAME})
 else()
-    if(EXISTS ${PROJ_ROOT}/.svn/)
-        find_package(Subversion REQUIRED)
-        if(SUBVERSION_FOUND)
-            Subversion_WC_INFO(${PROJ_ROOT} Project)
-            add_definitions(-DPADDLE_VERSION=${Project_WC_REVISION})
-        endif()
-    elseif(EXISTS ${PROJ_ROOT}/.git/)
-        find_package(Git REQUIRED)
   execute_process(
     COMMAND ${GIT_EXECUTABLE} log -1 --format=%H
     WORKING_DIRECTORY ${PROJ_ROOT}
@@ -83,12 +78,13 @@ else()
     RESULT_VARIABLE GIT_RESULT
     ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE)
   if(NOT ${GIT_RESULT})
-            add_definitions(-DPADDLE_VERSION=\"${GIT_SHA1}\")
+    set(PADDLE_VERSION ${GIT_SHA1})
   else()
+    set(PADDLE_VERSION "unknown")
     message(WARNING "Cannot add paddle version from git tag")
   endif()
-    endif()
 endif()
+add_definitions(-DPADDLE_VERSION=\"${PADDLE_VERSION}\")
 
 
 if(NOT WITH_GPU)