Index: libcxxabi/src/demangle/ItaniumDemangle.h
===================================================================
--- libcxxabi/src/demangle/ItaniumDemangle.h
+++ libcxxabi/src/demangle/ItaniumDemangle.h
@@ -737,7 +737,7 @@
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -752,7 +752,7 @@
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -1260,7 +1260,7 @@
   template<typename Fn> void match(Fn F) const { F(Name, Params); }
 
   void printLeft(OutputBuffer &OB) const override {
-    SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+    DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "template<";
     Params.printWithComma(OB);
     OB += "> typename ";
@@ -1396,8 +1396,8 @@
 
   void printLeft(OutputBuffer &OB) const override {
     constexpr unsigned Max = std::numeric_limits<unsigned>::max();
-    SwapAndRestore<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
-    SwapAndRestore<unsigned> SavePackMax(OB.CurrentPackMax, Max);
+    DynamicOverride<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
+    DynamicOverride<unsigned> SavePackMax(OB.CurrentPackMax, Max);
     size_t StreamPos = OB.getCurrentPosition();
 
     // Print the first element in the pack. If Child contains a ParameterPack,
@@ -1438,7 +1438,7 @@
   NodeArray getParams() { return Params; }
 
   void printLeft(OutputBuffer &OB) const override {
-    SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+    DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "<";
     Params.printWithComma(OB);
     if (OB.back() == '>')
@@ -1488,38 +1488,38 @@
   bool hasRHSComponentSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasRHSComponent(OB);
   }
   bool hasArraySlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasArray(OB);
   }
   bool hasFunctionSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasFunction(OB);
   }
   const Node *getSyntaxNode(OutputBuffer &OB) const override {
     if (Printing)
       return this;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->getSyntaxNode(OB);
   }
 
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     Ref->printLeft(OB);
   }
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     Ref->printRight(OB);
   }
 };
@@ -1736,7 +1736,7 @@
 
   void printDeclarator(OutputBuffer &OB) const {
     if (!TemplateParams.empty()) {
-      SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+      DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
       OB += "<";
       TemplateParams.printWithComma(OB);
       OB += ">";
@@ -1944,7 +1944,7 @@
   void printLeft(OutputBuffer &OB) const override {
     OB += CastKind;
     {
-      SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+      DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
       OB += "<";
       To->printLeft(OB);
       if (OB.back() == '>')
@@ -2911,8 +2911,8 @@
     return make<UnnamedTypeName>(Count);
   }
   if (consumeIf("Ul")) {
-    SwapAndRestore<size_t> SwapParams(ParsingLambdaParamsAtLevel,
-                                      TemplateParams.size());
+    DynamicOverride<size_t> SwapParams(ParsingLambdaParamsAtLevel,
+                                       TemplateParams.size());
     ScopedTemplateParamList LambdaTemplateParams(this);
 
     size_t ParamsBegin = Names.size();
@@ -3116,13 +3116,13 @@
   if (const auto *Op = parseOperatorEncoding()) {
     if (Op->getKind() == OperatorInfo::CCast) {
       //              ::= cv <type>    # (cast)
-      SwapAndRestore<bool> SaveTemplate(TryToParseTemplateArgs, false);
+      DynamicOverride<bool> SaveTemplate(TryToParseTemplateArgs, false);
       // If we're parsing an encoding, State != nullptr and the conversion
       // operators' <type> could have a <template-param> that refers to some
       // <template-arg>s further ahead in the mangled name.
-      SwapAndRestore<bool> SavePermit(PermitForwardTemplateReferences,
-                                      PermitForwardTemplateReferences ||
-                                          State != nullptr);
+      DynamicOverride<bool> SavePermit(PermitForwardTemplateReferences,
+                                       PermitForwardTemplateReferences ||
+                                           State != nullptr);
       Node *Ty = getDerived().parseType();
       if (Ty == nullptr)
         return nullptr;
@@ -3771,8 +3771,8 @@
       StringView ProtoSourceName = Qual.dropFront(std::strlen("objcproto"));
       StringView Proto;
       {
-        SwapAndRestore<const char *> SaveFirst(First, ProtoSourceName.begin()),
-                                     SaveLast(Last, ProtoSourceName.end());
+        DynamicOverride<const char *> SaveFirst(First, ProtoSourceName.begin()),
+            SaveLast(Last, ProtoSourceName.end());
         Proto = parseBareSourceName();
       }
       if (Proto.empty())
@@ -4252,7 +4252,7 @@
     return nullptr;
   Node *Ty;
   {
-    SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+    DynamicOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
     Ty = getDerived().parseType();
   }
 
@@ -4687,7 +4687,7 @@
       // C Cast: (type)expr
       Node *Ty;
       {
-        SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+        DynamicOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
         Ty = getDerived().parseType();
       }
       if (Ty == nullptr)
Index: libcxxabi/src/demangle/Utility.h
===================================================================
--- libcxxabi/src/demangle/Utility.h
+++ libcxxabi/src/demangle/Utility.h
@@ -177,21 +177,20 @@
   size_t getBufferCapacity() const { return BufferCapacity; }
 };
 
-template <class T> class SwapAndRestore {
-  T &Restore;
-  T OriginalValue;
+template <class T> class DynamicOverride {
+  T &Loc;
+  T Original;
 
 public:
-  SwapAndRestore(T &Restore_) : SwapAndRestore(Restore_, Restore_) {}
+  DynamicOverride(T &Loc_) : DynamicOverride(Loc_, Loc_) {}
 
-  SwapAndRestore(T &Restore_, T NewVal)
-      : Restore(Restore_), OriginalValue(Restore) {
-    Restore = std::move(NewVal);
+  DynamicOverride(T &Loc_, T NewVal) : Loc(Loc_), Original(Loc_) {
+    Loc_ = std::move(NewVal);
   }
-  ~SwapAndRestore() { Restore = std::move(OriginalValue); }
+  ~DynamicOverride() { Loc = std::move(Original); }
 
-  SwapAndRestore(const SwapAndRestore &) = delete;
-  SwapAndRestore &operator=(const SwapAndRestore &) = delete;
+  DynamicOverride(const DynamicOverride &) = delete;
+  DynamicOverride &operator=(const DynamicOverride &) = delete;
 };
 
 DEMANGLE_NAMESPACE_END
Index: llvm/include/llvm/Demangle/ItaniumDemangle.h
===================================================================
--- llvm/include/llvm/Demangle/ItaniumDemangle.h
+++ llvm/include/llvm/Demangle/ItaniumDemangle.h
@@ -737,7 +737,7 @@
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -752,7 +752,7 @@
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -1260,7 +1260,7 @@
   template<typename Fn> void match(Fn F) const { F(Name, Params); }
 
   void printLeft(OutputBuffer &OB) const override {
-    SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+    DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "template<";
     Params.printWithComma(OB);
     OB += "> typename ";
@@ -1396,8 +1396,8 @@
 
   void printLeft(OutputBuffer &OB) const override {
     constexpr unsigned Max = std::numeric_limits<unsigned>::max();
-    SwapAndRestore<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
-    SwapAndRestore<unsigned> SavePackMax(OB.CurrentPackMax, Max);
+    DynamicOverride<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
+    DynamicOverride<unsigned> SavePackMax(OB.CurrentPackMax, Max);
     size_t StreamPos = OB.getCurrentPosition();
 
     // Print the first element in the pack. If Child contains a ParameterPack,
@@ -1438,7 +1438,7 @@
   NodeArray getParams() { return Params; }
 
   void printLeft(OutputBuffer &OB) const override {
-    SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+    DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "<";
     Params.printWithComma(OB);
     if (OB.back() == '>')
@@ -1488,38 +1488,38 @@
   bool hasRHSComponentSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasRHSComponent(OB);
   }
   bool hasArraySlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasArray(OB);
   }
   bool hasFunctionSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->hasFunction(OB);
   }
   const Node *getSyntaxNode(OutputBuffer &OB) const override {
     if (Printing)
       return this;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     return Ref->getSyntaxNode(OB);
   }
 
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     Ref->printLeft(OB);
   }
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    DynamicOverride<bool> SavePrinting(Printing, true);
     Ref->printRight(OB);
   }
 };
@@ -1736,7 +1736,7 @@
 
   void printDeclarator(OutputBuffer &OB) const {
     if (!TemplateParams.empty()) {
-      SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+      DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
       OB += "<";
       TemplateParams.printWithComma(OB);
       OB += ">";
@@ -1944,7 +1944,7 @@
   void printLeft(OutputBuffer &OB) const override {
     OB += CastKind;
     {
-      SwapAndRestore<unsigned> LT(OB.GtIsGt, 0);
+      DynamicOverride<unsigned> LT(OB.GtIsGt, 0);
       OB += "<";
       To->printLeft(OB);
       if (OB.back() == '>')
@@ -2911,8 +2911,8 @@
     return make<UnnamedTypeName>(Count);
   }
   if (consumeIf("Ul")) {
-    SwapAndRestore<size_t> SwapParams(ParsingLambdaParamsAtLevel,
-                                      TemplateParams.size());
+    DynamicOverride<size_t> SwapParams(ParsingLambdaParamsAtLevel,
+                                       TemplateParams.size());
     ScopedTemplateParamList LambdaTemplateParams(this);
 
     size_t ParamsBegin = Names.size();
@@ -3116,13 +3116,13 @@
   if (const auto *Op = parseOperatorEncoding()) {
     if (Op->getKind() == OperatorInfo::CCast) {
       //              ::= cv <type>    # (cast)
-      SwapAndRestore<bool> SaveTemplate(TryToParseTemplateArgs, false);
+      DynamicOverride<bool> SaveTemplate(TryToParseTemplateArgs, false);
       // If we're parsing an encoding, State != nullptr and the conversion
       // operators' <type> could have a <template-param> that refers to some
       // <template-arg>s further ahead in the mangled name.
-      SwapAndRestore<bool> SavePermit(PermitForwardTemplateReferences,
-                                      PermitForwardTemplateReferences ||
-                                          State != nullptr);
+      DynamicOverride<bool> SavePermit(PermitForwardTemplateReferences,
+                                       PermitForwardTemplateReferences ||
+                                           State != nullptr);
       Node *Ty = getDerived().parseType();
       if (Ty == nullptr)
         return nullptr;
@@ -3771,8 +3771,8 @@
       StringView ProtoSourceName = Qual.dropFront(std::strlen("objcproto"));
       StringView Proto;
       {
-        SwapAndRestore<const char *> SaveFirst(First, ProtoSourceName.begin()),
-                                     SaveLast(Last, ProtoSourceName.end());
+        DynamicOverride<const char *> SaveFirst(First, ProtoSourceName.begin()),
+            SaveLast(Last, ProtoSourceName.end());
         Proto = parseBareSourceName();
       }
       if (Proto.empty())
@@ -4252,7 +4252,7 @@
     return nullptr;
   Node *Ty;
   {
-    SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+    DynamicOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
     Ty = getDerived().parseType();
   }
 
@@ -4687,7 +4687,7 @@
       // C Cast: (type)expr
       Node *Ty;
       {
-        SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+        DynamicOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
         Ty = getDerived().parseType();
       }
       if (Ty == nullptr)
Index: llvm/include/llvm/Demangle/Utility.h
===================================================================
--- llvm/include/llvm/Demangle/Utility.h
+++ llvm/include/llvm/Demangle/Utility.h
@@ -177,21 +177,20 @@
   size_t getBufferCapacity() const { return BufferCapacity; }
 };
 
-template <class T> class SwapAndRestore {
-  T &Restore;
-  T OriginalValue;
+template <class T> class DynamicOverride {
+  T &Loc;
+  T Original;
 
 public:
-  SwapAndRestore(T &Restore_) : SwapAndRestore(Restore_, Restore_) {}
+  DynamicOverride(T &Loc_) : DynamicOverride(Loc_, Loc_) {}
 
-  SwapAndRestore(T &Restore_, T NewVal)
-      : Restore(Restore_), OriginalValue(Restore) {
-    Restore = std::move(NewVal);
+  DynamicOverride(T &Loc_, T NewVal) : Loc(Loc_), Original(Loc_) {
+    Loc_ = std::move(NewVal);
   }
-  ~SwapAndRestore() { Restore = std::move(OriginalValue); }
+  ~DynamicOverride() { Loc = std::move(Original); }
 
-  SwapAndRestore(const SwapAndRestore &) = delete;
-  SwapAndRestore &operator=(const SwapAndRestore &) = delete;
+  DynamicOverride(const DynamicOverride &) = delete;
+  DynamicOverride &operator=(const DynamicOverride &) = delete;
 };
 
 DEMANGLE_NAMESPACE_END
Index: llvm/lib/Demangle/RustDemangle.cpp
===================================================================
--- llvm/lib/Demangle/RustDemangle.cpp
+++ llvm/lib/Demangle/RustDemangle.cpp
@@ -23,9 +23,9 @@
 
 using namespace llvm;
 
+using llvm::itanium_demangle::DynamicOverride;
 using llvm::itanium_demangle::OutputBuffer;
 using llvm::itanium_demangle::StringView;
-using llvm::itanium_demangle::SwapAndRestore;
 
 namespace {
 
@@ -119,7 +119,7 @@
     if (!Print)
       return;
 
-    SwapAndRestore<size_t> SavePosition(Position, Position);
+    DynamicOverride<size_t> SavePosition(Position, Position);
     Position = Backref;
     Demangler();
   }
@@ -235,7 +235,7 @@
   demanglePath(IsInType::No);
 
   if (Position != Input.size()) {
-    SwapAndRestore<bool> SavePrint(Print, false);
+    DynamicOverride<bool> SavePrint(Print, false);
     demanglePath(IsInType::No);
   }
 
@@ -273,7 +273,8 @@
     Error = true;
     return false;
   }
-  SwapAndRestore<size_t> SaveRecursionLevel(RecursionLevel, RecursionLevel + 1);
+  DynamicOverride<size_t> SaveRecursionLevel(RecursionLevel,
+                                             RecursionLevel + 1);
 
   switch (consume()) {
   case 'C': {
@@ -374,7 +375,7 @@
 // <impl-path> = [<disambiguator>] <path>
 // <disambiguator> = "s" <base-62-number>
 void Demangler::demangleImplPath(IsInType InType) {
-  SwapAndRestore<bool> SavePrint(Print, false);
+  DynamicOverride<bool> SavePrint(Print, false);
   parseOptionalBase62Number('s');
   demanglePath(InType);
 }
@@ -568,7 +569,8 @@
     Error = true;
     return;
   }
-  SwapAndRestore<size_t> SaveRecursionLevel(RecursionLevel, RecursionLevel + 1);
+  DynamicOverride<size_t> SaveRecursionLevel(RecursionLevel,
+                                             RecursionLevel + 1);
 
   size_t Start = Position;
   char C = consume();
@@ -651,7 +653,7 @@
 // <abi> = "C"
 //       | <undisambiguated-identifier>
 void Demangler::demangleFnSig() {
-  SwapAndRestore<size_t> SaveBoundLifetimes(BoundLifetimes, BoundLifetimes);
+  DynamicOverride<size_t> SaveBoundLifetimes(BoundLifetimes, BoundLifetimes);
   demangleOptionalBinder();
 
   if (consumeIf('U'))
@@ -693,7 +695,7 @@
 
 // <dyn-bounds> = [<binder>] {<dyn-trait>} "E"
 void Demangler::demangleDynBounds() {
-  SwapAndRestore<size_t> SaveBoundLifetimes(BoundLifetimes, BoundLifetimes);
+  DynamicOverride<size_t> SaveBoundLifetimes(BoundLifetimes, BoundLifetimes);
   print("dyn ");
   demangleOptionalBinder();
   for (size_t I = 0; !Error && !consumeIf('E'); ++I) {
@@ -757,7 +759,8 @@
     Error = true;
     return;
   }
-  SwapAndRestore<size_t> SaveRecursionLevel(RecursionLevel, RecursionLevel + 1);
+  DynamicOverride<size_t> SaveRecursionLevel(RecursionLevel,
+                                             RecursionLevel + 1);
 
   char C = consume();
   BasicType Type;