Move primitiveOpNames out from PrimitiveOpTypeName(), as local static variables are not thread-safe under VS2013.

Source/CNTKv2LibraryDll/Function.h

@@ -28,8 +28,8 @@ namespace std
 
 namespace CNTK
 {
-    inline const std::wstring& PrimitiveOpTypeName(PrimitiveOpType opType)
-    {
+    // Move primitiveOpNames out from PrimitiveOpTypeName(), as local static variables are not thread-safe under VS2013.
+    // Todo: Move it into PrimitiveOpTypeName() as local static after upgraded to VS2015.
     static const std::unordered_map<PrimitiveOpType, std::wstring> primitiveOpNames = {
         {PrimitiveOpType::Negate, L"Negate"},
         {PrimitiveOpType::Sigmoid, L"Sigmoid"},
@@ -80,6 +80,8 @@ namespace CNTK
         {PrimitiveOpType::RandomSampleInclusionFrequency, L"RandomSampleInclusionFrequency"},
     };
 
+    inline const std::wstring& PrimitiveOpTypeName(PrimitiveOpType opType)
+    {
         if (primitiveOpNames.find(opType) == primitiveOpNames.end())
             LogicError("Unknown PrimitiveOpType");