Enable core api exporting in Windows

build.bat

@@ -18,7 +18,7 @@
 SET BASE_PATH=%CD%
 SET BUILD_PATH=%BASE_PATH%/build
 
-SET threads=6
+SET threads=8
 SET ENABLE_GITEE=OFF
 
 set VERSION_MAJOR=''

mindspore/ccsrc/minddata/dataset/CMakeLists.txt

@@ -267,6 +267,7 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
     else()
         target_link_libraries(_c_dataengine PRIVATE ${SECUREC_LIBRARY})
     endif()
+    target_link_options(_c_dataengine PRIVATE -Wl,--allow-multiple-definition)
 else()
     set(ICU_LIB mindspore::icuuc mindspore::icudata mindspore::icui18n)
     if(ENABLE_PYTHON)

mindspore/core/mindrt/CMakeLists.txt

@@ -11,4 +11,8 @@ file(GLOB MINDRT_SRC
     ${CMAKE_CURRENT_SOURCE_DIR}/src/thread/*.cc
     )
 
+if(CMAKE_SYSTEM_NAME MATCHES "Windows")
+    add_compile_definitions(BUILDING_DLL)
+endif()
+
 add_library(mindrt_mid OBJECT ${MINDRT_SRC})

mindspore/core/utils/visible.h

@@ -18,12 +18,11 @@
 #define MINDSPORE_CORE_UTILS_VISIBLE_H_
 
 #if (defined(_WIN32) || defined(__WIN32__) || defined(WIN32) || defined(__CYGWIN__))
-// Because it extremely slow down compile time in mingw,
-// core api exporting is disabled for Windows.
-#define MS_CORE_API
 #ifdef BUILDING_DLL
+#define MS_CORE_API __declspec(dllexport)
 #define MS_EXPORT __declspec(dllexport)
 #else
+#define MS_CORE_API __declspec(dllimport)
 #define MS_EXPORT __declspec(dllimport)
 #endif
 #define MS_LOCAL