[YAMLParser] Don't crash on null keys in KeyValueNodes.

Found by clangd-fuzzer!

llvm-svn: 318935

2 files changed, 6 insertions, 3 deletions

diff --git a/llvm/include/llvm/Support/YAMLParser.h b/llvm/include/llvm/Support/YAMLParser.h
index 626507947a7..859c2c1f7b3 100644
--- a/llvm/include/llvm/Support/YAMLParser.h
+++ b/llvm/include/llvm/Support/YAMLParser.h
@@ -291,9 +291,11 @@ public:
   Node *getValue();
 
   void skip() override {
-    getKey()->skip();
-    if (Node *Val = getValue())
-      Val->skip();
+    if (Node *Val = getKey()) {
+      Key->skip();
+      if (Node *Val = getValue())
+        Val->skip();
+    }
   }
 
   static bool classof(const Node *N) {
diff --git a/llvm/unittests/Support/YAMLParserTest.cpp b/llvm/unittests/Support/YAMLParserTest.cpp
index d411a286830..7962f3ca1ad 100644
--- a/llvm/unittests/Support/YAMLParserTest.cpp
+++ b/llvm/unittests/Support/YAMLParserTest.cpp
@@ -180,6 +180,7 @@ TEST(YAMLParser, HandlesEndOfFileGracefully) {
 }
 
 TEST(YAMLParser, HandlesNullValuesInKeyValueNodesGracefully) {
+  ExpectParseError("KeyValueNode with null key", "? \"\n:");
   ExpectParseError("KeyValueNode with null value", "test: '");
 }