diff --git a/libcxxabi/src/demangle/DemangleConfig.h b/libcxxabi/src/demangle/DemangleConfig.h
index 7904e9d1eb133..79dbeb89cc28f 100644
--- a/libcxxabi/src/demangle/DemangleConfig.h
+++ b/libcxxabi/src/demangle/DemangleConfig.h
@@ -115,4 +115,8 @@
 #define DEMANGLE_NAMESPACE_BEGIN namespace { namespace itanium_demangle {
 #define DEMANGLE_NAMESPACE_END } }
 
+// The DEMANGLE_ABI macro resolves to nothing when building libc++abi. Only
+// the llvm copy defines DEMANGLE_ABI as a visibility attribute.
+#define DEMANGLE_ABI
+
 #endif // LIBCXXABI_DEMANGLE_DEMANGLE_CONFIG_H
diff --git a/libcxxabi/src/demangle/ItaniumDemangle.h b/libcxxabi/src/demangle/ItaniumDemangle.h
index b306b2013445c..708f31728967d 100644
--- a/libcxxabi/src/demangle/ItaniumDemangle.h
+++ b/libcxxabi/src/demangle/ItaniumDemangle.h
@@ -1366,7 +1366,7 @@ class TemplateTemplateParamDecl final : public Node {
   template <typename Fn> void match(Fn F) const { F(Name, Params, Requires); }
 
   void printLeft(OutputBuffer &OB) const override {
-    ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
+    ScopedOverride<bool> LT(OB.TemplateTracker.InsideTemplate, true);
     OB += "template<";
     Params.printWithComma(OB);
     OB += "> typename ";
@@ -1550,7 +1550,7 @@ class TemplateArgs final : public Node {
   NodeArray getParams() { return Params; }
 
   void printLeft(OutputBuffer &OB) const override {
-    ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
+    ScopedOverride<bool> LT(OB.TemplateTracker.InsideTemplate, true);
     OB += "<";
     Params.printWithComma(OB);
     OB += ">";
@@ -1824,7 +1824,7 @@ class ClosureTypeName : public Node {
 
   void printDeclarator(OutputBuffer &OB) const {
     if (!TemplateParams.empty()) {
-      ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
+      ScopedOverride<bool> LT(OB.TemplateTracker.InsideTemplate, true);
       OB += "<";
       TemplateParams.printWithComma(OB);
       OB += ">";
@@ -1885,7 +1885,9 @@ class BinaryExpr : public Node {
   }
 
   void printLeft(OutputBuffer &OB) const override {
-    bool ParenAll = OB.isGtInsideTemplateArgs() &&
+    // If we're printing a '<' inside of a template argument, and we haven't
+    // yet parenthesized the expression, do so now.
+    bool ParenAll = !OB.isInParensInTemplateArgs() &&
                     (InfixOperator == ">" || InfixOperator == ">>");
     if (ParenAll)
       OB.printOpen();
@@ -2061,7 +2063,7 @@ class CastExpr : public Node {
   void printLeft(OutputBuffer &OB) const override {
     OB += CastKind;
     {
-      ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
+      ScopedOverride<bool> LT(OB.TemplateTracker.InsideTemplate, true);
       OB += "<";
       OB.printLeft(*To);
       OB += ">";
@@ -3049,7 +3051,8 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
   Node *parse(bool ParseParams = true);
 };
 
-const char* parse_discriminator(const char* first, const char* last);
+DEMANGLE_ABI const char *parse_discriminator(const char *first,
+                                             const char *last);
 
 // <name> ::= <nested-name> // N
 //        ::= <local-name> # See Scope Encoding below  // Z
@@ -4878,8 +4881,22 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExprPrimary() {
     return nullptr;
   }
   case 'D':
+    switch (look(1))
+    {
+        case 'i': // char32_t
+            First += 2;
+            return getDerived().parseIntegerLiteral("char32_t");
+        case 's': // char16_t
+            First += 2;
+            return getDerived().parseIntegerLiteral("char16_t");
+        case 'u': // char8_t
+            First += 2;
+            return getDerived().parseIntegerLiteral("char8_t");
+        default:
+    }
     if (consumeIf("Dn") && (consumeIf('0'), consumeIf('E')))
       return make<NameType>("nullptr");
+
     return nullptr;
   case 'T':
     // Invalid mangled name per
diff --git a/libcxxabi/src/demangle/Utility.h b/libcxxabi/src/demangle/Utility.h
index 8829f3fa13a93..df5b54dca492d 100644
--- a/libcxxabi/src/demangle/Utility.h
+++ b/libcxxabi/src/demangle/Utility.h
@@ -81,7 +81,7 @@ class OutputBuffer {
   OutputBuffer(const OutputBuffer &) = delete;
   OutputBuffer &operator=(const OutputBuffer &) = delete;
 
-  virtual ~OutputBuffer() {}
+  virtual ~OutputBuffer() = default;
 
   operator std::string_view() const {
     return std::string_view(Buffer, CurrentPosition);
@@ -104,18 +104,32 @@ class OutputBuffer {
   unsigned CurrentPackIndex = std::numeric_limits<unsigned>::max();
   unsigned CurrentPackMax = std::numeric_limits<unsigned>::max();
 
-  /// When zero, we're printing template args and '>' needs to be parenthesized.
-  /// Use a counter so we can simply increment inside parentheses.
-  unsigned GtIsGt = 1;
+  struct {
+    /// The depth of '(' and ')' inside the currently printed template
+    /// arguments.
+    unsigned ParenDepth = 0;
 
-  bool isGtInsideTemplateArgs() const { return GtIsGt == 0; }
+    /// True if we're currently printing a template argument.
+    bool InsideTemplate = false;
+  } TemplateTracker;
+
+  /// Returns true if we're currently between a '(' and ')' when printing
+  /// template args.
+  bool isInParensInTemplateArgs() const {
+    return TemplateTracker.ParenDepth > 0;
+  }
+
+  /// Returns true if we're printing template args.
+  bool isInsideTemplateArgs() const { return TemplateTracker.InsideTemplate; }
 
   void printOpen(char Open = '(') {
-    GtIsGt++;
+    if (isInsideTemplateArgs())
+      TemplateTracker.ParenDepth++;
     *this += Open;
   }
   void printClose(char Close = ')') {
-    GtIsGt--;
+    if (isInsideTemplateArgs())
+      TemplateTracker.ParenDepth--;
     *this += Close;
   }
 
diff --git a/libcxxabi/src/demangle/cp-to-llvm.sh b/libcxxabi/src/demangle/cp-to-llvm.sh
index f773dff9f0a8b..9c1db6fec29a6 100755
--- a/libcxxabi/src/demangle/cp-to-llvm.sh
+++ b/libcxxabi/src/demangle/cp-to-llvm.sh
@@ -42,6 +42,7 @@ copy_files() {
     chmod -w $dst/README.txt
 
     for I in $hdrs ; do
+	    echo "Copying ${src}/$I to ${dst}/$I"
 	    rm -f $dst/$I
 	    dash=$(echo "$I---------------------------" | cut -c -27 |\
 		       sed 's|[^-]*||')
@@ -53,6 +54,6 @@ copy_files() {
 }
 
 if [[ $ANSWER =~ ^[Yy]$ ]]; then
-    copy_files . $LLVM_DEMANGLE_DIR $HDRS
-    copy_files ../../test $LLVM_TESTING_DIR $TEST_HDRS
+    copy_files . $LLVM_DEMANGLE_DIR "${HDRS}"
+    copy_files ../../test $LLVM_TESTING_DIR "${TEST_HDRS}"
 fi