Implement PR2773, support for __USER_LABEL_PREFIX__


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57127 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 8a11925..20692ba 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -39,6 +39,7 @@
   LongDoubleFormat = &llvm::APFloat::IEEEdouble;
   DescriptionString = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
                       "i64:64:64-f32:32:32-f64:64:64";
+  UserLabelPrefix = "_";
 }
 
 // Out of line virtual dtor for TargetInfo.