diff --git a/llvm/lib/Support/YAMLParser.cpp b/llvm/lib/Support/YAMLParser.cpp
--- a/llvm/lib/Support/YAMLParser.cpp
+++ b/llvm/lib/Support/YAMLParser.cpp
@@ -159,6 +159,18 @@
   Token() = default;
 };
 
+enum BlockStyleIndicator : char {
+  BSI_None = ' ',
+  BSI_Literal = '|',
+  BSI_Folded = '>'
+};
+
+enum BlockChompingIndicator : char {
+  BCI_Clip = ' ',
+  BCI_Strip = '-',
+  BCI_Keep = '+'
+};
+
 } // end namespace yaml
 } // end namespace llvm
 
@@ -479,14 +491,15 @@
   /// YAML does not consider the style indicator to be a part of the header.
   ///
   /// Return false if an error occurred.
-  bool scanBlockScalarIndicators(char &StyleIndicator, char &ChompingIndicator,
+  bool scanBlockScalarIndicators(BlockStyleIndicator &StyleIndicator,
+                                 BlockChompingIndicator &ChompingIndicator,
                                  unsigned &IndentIndicator, bool &IsDone);
 
   /// Scan a style indicator in a block scalar header.
-  char scanBlockStyleIndicator();
+  BlockStyleIndicator scanBlockStyleIndicator();
 
   /// Scan a chomping indicator in a block scalar header.
-  char scanBlockChompingIndicator();
+  BlockChompingIndicator scanBlockChompingIndicator();
 
   /// Scan an indentation indicator in a block scalar header.
   unsigned scanBlockIndentationIndicator();
@@ -494,8 +507,8 @@
   /// Scan a block scalar header.
   ///
   /// Return false if an error occurred.
-  bool scanBlockScalarHeader(char &ChompingIndicator, unsigned &IndentIndicator,
-                             bool &IsDone);
+  bool scanBlockScalarHeader(BlockChompingIndicator &ChompingIndicator,
+                             unsigned &IndentIndicator, bool &IsDone);
 
   /// Look for the indentation level of a block scalar.
   ///
@@ -1538,30 +1551,40 @@
   return true;
 }
 
-bool Scanner::scanBlockScalarIndicators(char &StyleIndicator,
-                                        char &ChompingIndicator,
-                                        unsigned &IndentIndicator,
-                                        bool &IsDone) {
+bool Scanner::scanBlockScalarIndicators(
+    BlockStyleIndicator &StyleIndicator,
+    BlockChompingIndicator &ChompingIndicator, unsigned &IndentIndicator,
+    bool &IsDone) {
   StyleIndicator = scanBlockStyleIndicator();
   if (!scanBlockScalarHeader(ChompingIndicator, IndentIndicator, IsDone))
     return false;
   return true;
 }
 
-char Scanner::scanBlockStyleIndicator() {
-  char Indicator = ' ';
-  if (Current != End && (*Current == '>' || *Current == '|')) {
-    Indicator = *Current;
-    skip(1);
+BlockStyleIndicator Scanner::scanBlockStyleIndicator() {
+  BlockStyleIndicator Indicator = BSI_None;
+  if (Current != End) {
+    if (*Current == '>') {
+      Indicator = BSI_Folded;
+      skip(1);
+    } else if (*Current == '|') {
+      Indicator = BSI_Literal;
+      skip(1);
+    }
   }
   return Indicator;
 }
 
-char Scanner::scanBlockChompingIndicator() {
-  char Indicator = ' ';
-  if (Current != End && (*Current == '+' || *Current == '-')) {
-    Indicator = *Current;
-    skip(1);
+BlockChompingIndicator Scanner::scanBlockChompingIndicator() {
+  BlockChompingIndicator Indicator = BCI_Clip;
+  if (Current != End) {
+    if (*Current == '+') {
+      Indicator = BCI_Keep;
+      skip(1);
+    } else if (*Current == '-') {
+      Indicator = BCI_Strip;
+      skip(1);
+    }
   }
   return Indicator;
 }
@@ -1570,11 +1593,11 @@
 ///
 /// Return the number of trailing line breaks to emit, depending on
 /// \p ChompingIndicator.
-static unsigned getChompedLineBreaks(char ChompingIndicator,
+static unsigned getChompedLineBreaks(BlockChompingIndicator ChompingIndicator,
                                      unsigned LineBreaks, StringRef Str) {
-  if (ChompingIndicator == '-') // Strip all line breaks.
+  if (ChompingIndicator == BCI_Strip) // Strip all line breaks.
     return 0;
-  if (ChompingIndicator == '+') // Keep all line breaks.
+  if (ChompingIndicator == BCI_Keep) // Keep all line breaks.
     return LineBreaks;
   // Clip trailing lines.
   return Str.empty() ? 0 : 1;
@@ -1589,14 +1612,14 @@
   return Indent;
 }
 
-bool Scanner::scanBlockScalarHeader(char &ChompingIndicator,
+bool Scanner::scanBlockScalarHeader(BlockChompingIndicator &ChompingIndicator,
                                     unsigned &IndentIndicator, bool &IsDone) {
   auto Start = Current;
 
   ChompingIndicator = scanBlockChompingIndicator();
   IndentIndicator = scanBlockIndentationIndicator();
   // Check for the chomping indicator once again.
-  if (ChompingIndicator == ' ')
+  if (ChompingIndicator == BCI_Clip)
     ChompingIndicator = scanBlockChompingIndicator();
   Current = skip_while(&Scanner::skip_s_white, Current);
   skipComment();
@@ -1696,8 +1719,8 @@
 
 bool Scanner::scanBlockScalar(bool IsLiteral) {
   assert(*Current == '|' || *Current == '>');
-  char StyleIndicator;
-  char ChompingIndicator;
+  BlockStyleIndicator StyleIndicator;
+  BlockChompingIndicator ChompingIndicator;
   unsigned BlockIndent;
   bool IsDone = false;
   if (!scanBlockScalarIndicators(StyleIndicator, ChompingIndicator, BlockIndent,
@@ -1705,7 +1728,6 @@
     return false;
   if (IsDone)
     return true;
-  bool IsFolded = StyleIndicator == '>';
 
   const auto *Start = Current;
   unsigned BlockExitIndent = Indent < 0 ? 0 : (unsigned)Indent;
@@ -1728,7 +1750,8 @@
     auto LineStart = Current;
     advanceWhile(&Scanner::skip_nb_char);
     if (LineStart != Current) {
-      if (LineBreaks && IsFolded && !Scanner::isLineEmpty(Str)) {
+      if (LineBreaks && StyleIndicator == BSI_Folded &&
+          !Scanner::isLineEmpty(Str)) {
         // The folded style "folds" any single line break between content into a
         // single space, except when that content is "empty" (only contains
         // whitespace) in which case the line break is left as-is.