AsmParser: Recognize DW_TAG_* constants

Recognize `DW_TAG_` constants in assembly, and output it by default for
`GenericDebugNode`.

llvm-svn: 228042
diff --git a/llvm/utils/vim/llvm.vim b/llvm/utils/vim/llvm.vim
index b7411c3..57c7133 100644
--- a/llvm/utils/vim/llvm.vim
+++ b/llvm/utils/vim/llvm.vim
@@ -77,6 +77,7 @@
 syn match   llvmIdentifier /![-a-zA-Z$._][-a-zA-Z$._0-9]*\ze\s*$/
 syn match   llvmIdentifier /![-a-zA-Z$._][-a-zA-Z$._0-9]*\ze\s*[=!]/
 syn match   llvmType /!\zs\a\+\ze\s*(/
+syn match   llvmConstant /\<DW_TAG_[a-z_]\+\>/
 
 " Syntax-highlight dejagnu test commands.
 syn match  llvmSpecialComment /;\s*RUN:.*$/