AsmParser: Don't crash on an ill-formed MDNodeVector

llvm-svn: 224056

llvm/lib/AsmParser/LLParser.cpp

@@ -2968,8 +2968,8 @@ bool LLParser::ParseMetadataAsValue(ValID &ID, PerFunctionState *PFS) {
 ///  ::= !{...}
 ///  ::= !"string"
 bool LLParser::ParseMetadata(Metadata *&MD, PerFunctionState *PFS) {
-  assert(Lex.getKind() == lltok::exclaim);
-  Lex.Lex();
+  if (ParseToken(lltok::exclaim, "expected '!' here"))
+    return true;
 
   // MDNode:
   // !{ ... }

llvm/test/Assembler/invalid-mdnode-vector2.ll

@@ -0,0 +1,4 @@
+; RUN: not llvm-as < %s 2>&1 | FileCheck %s
+
+!0 = metadata !{metadata
+; CHECK: expected '!' here