Add the default constructor DwarfAccelTable::DataArray() to initialize (MCSymbol*)StrSym explicitly.

It will fix crash in codegen on msvc x64.

llvm-svn: 207356
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h b/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
index c2794c7..5d6c847 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
@@ -183,6 +183,7 @@
   struct DataArray {
     MCSymbol *StrSym;
     std::vector<HashDataContents *> Values;
+    DataArray() : StrSym(nullptr), Values() {}
   };
   friend struct HashData;
   struct HashData {