Add a basic "re-mangler", which turns a parsed

demangling tree back into a mangled string.

Also, extend the demangling API in a few obvious
ways, and simplify testing for failure in the
node-returning APIs by having them simply return
null instead of a spurious Failure node.

Also, preserve slightly more information in the
demangling tree.  The goal here is eventually to
always allow a perfect round-trip through the
demangler parse tree.  This patch gets us close,
but we're not quite there yet.

Tests to follow.

Swift SVN r24473

include/swift/Basic/DemangleNodes.def

@@ -18,22 +18,28 @@
 /// NODE(ID)
 ///   The node's enumerator value is Node::Kind::ID.
 
-NODE(Failure)
-NODE(Allocator)
-NODE(ArchetypeAndProtocol)
+/// CONTEXT_NODE(ID)
+///   Nodes that can serve as contexts for other entities.
+#ifndef CONTEXT_NODE
+#define CONTEXT_NODE(ID) NODE(ID)
+#endif
+
+CONTEXT_NODE(Allocator)
+NODE(Archetype)
 NODE(ArchetypeRef)
 NODE(ArgumentTuple)
+NODE(AssociatedType)
 NODE(AssociatedTypeRef)
 NODE(AutoClosureType)
 NODE(BoundGenericClass)
 NODE(BoundGenericEnum)
 NODE(BoundGenericStructure)
 NODE(BuiltinTypeName)
-NODE(Class)
-NODE(Constructor)
-NODE(Deallocator)
+CONTEXT_NODE(Class)
+CONTEXT_NODE(Constructor)
+CONTEXT_NODE(Deallocator)
 NODE(DeclContext)
-NODE(DefaultArgumentInitializer)
+CONTEXT_NODE(DefaultArgumentInitializer)
 NODE(DependentGenericSignature)
 NODE(DependentGenericParamCount)
 NODE(DependentGenericConformanceRequirement)
@@ -43,63 +49,68 @@ NODE(DependentMemberType)
 NODE(DependentGenericParamType)
 NODE(DependentProtocolWitnessTableGenerator)
 NODE(DependentProtocolWitnessTableTemplate)
-NODE(Destructor)
-NODE(DidSet)
+CONTEXT_NODE(Destructor)
+CONTEXT_NODE(DidSet)
 NODE(Directness)
 NODE(DynamicAttribute)
 NODE(DynamicSelf)
-NODE(Enum)
+CONTEXT_NODE(Enum)
 NODE(ErrorType)
 NODE(ExistentialMetatype)
-NODE(ExplicitClosure)
-NODE(Extension)
+CONTEXT_NODE(ExplicitClosure)
+CONTEXT_NODE(Extension)
 NODE(FieldOffset)
-NODE(Function)
+CONTEXT_NODE(Function)
+NODE(FunctionSignatureSpecialization)
+NODE(FunctionSignatureSpecializationParam)
+NODE(FunctionSignatureSpecializationParamInfo)
 NODE(FunctionType)
 NODE(Generics)
+NODE(GenericSpecialization)
+NODE(GenericSpecializationParam)
 NODE(GenericType)
 NODE(GenericTypeMetadataPattern)
-NODE(Getter)
+CONTEXT_NODE(Getter)
 NODE(Global)
-NODE(GlobalGetter)
+CONTEXT_NODE(GlobalGetter)
 NODE(Identifier)
-NODE(IVarInitializer)
-NODE(IVarDestroyer)
+CONTEXT_NODE(IVarInitializer)
+CONTEXT_NODE(IVarDestroyer)
 NODE(ImplConvention)
 NODE(ImplFunctionAttribute)
 NODE(ImplFunctionType)
-NODE(ImplicitClosure)
+CONTEXT_NODE(ImplicitClosure)
 NODE(ImplParameter)
 NODE(ImplResult)
 NODE(InOut)
 NODE(InfixOperator)
-NODE(Initializer)
+CONTEXT_NODE(Initializer)
 NODE(LazyProtocolWitnessTableAccessor)
 NODE(LazyProtocolWitnessTableTemplate)
 NODE(LocalDeclName)
-NODE(MaterializeForSet)
+CONTEXT_NODE(MaterializeForSet)
 NODE(Metatype)
 NODE(MetatypeRepresentation)
 NODE(Metaclass)
-NODE(Module)
-NODE(NativeOwningAddressor)
-NODE(NativeOwningMutableAddressor)
-NODE(NativePinningAddressor)
-NODE(NativePinningMutableAddressor)
+CONTEXT_NODE(Module)
+CONTEXT_NODE(NativeOwningAddressor)
+CONTEXT_NODE(NativeOwningMutableAddressor)
+CONTEXT_NODE(NativePinningAddressor)
+CONTEXT_NODE(NativePinningMutableAddressor)
 NODE(NominalTypeDescriptor)
 NODE(NonObjCAttribute)
 NODE(NonVariadicTuple)
 NODE(Number)
 NODE(ObjCAttribute)
 NODE(ObjCBlock)
-NODE(OwningAddressor)
-NODE(OwningMutableAddressor)
+CONTEXT_NODE(OwningAddressor)
+CONTEXT_NODE(OwningMutableAddressor)
 NODE(PartialApplyForwarder)
 NODE(PartialApplyObjCForwarder)
 NODE(PostfixOperator)
 NODE(PrefixOperator)
 NODE(PrivateDeclName)
-NODE(Protocol)
+CONTEXT_NODE(Protocol)
 NODE(ProtocolConformance)
 NODE(ProtocolList)
 NODE(ProtocolWitness)
@@ -109,37 +120,32 @@ NODE(ReabstractionThunk)
 NODE(ReabstractionThunkHelper)
 NODE(ReturnType)
 NODE(SelfTypeRef)
-NODE(Setter)
-NODE(SpecializedAttribute)
-NODE(SpecializationKind)
-NODE(GenericSpecializationParam)
-NODE(FunctionSignatureSpecializationParam)
-NODE(FunctionSignatureSpecializationParamInfo)
-NODE(Structure)
-NODE(Subscript)
+CONTEXT_NODE(Setter)
+CONTEXT_NODE(Structure)
+CONTEXT_NODE(Subscript)
 NODE(Suffix)
 NODE(ThinFunctionType)
 NODE(TupleElement)
 NODE(TupleElementName)
-NODE(TupleElementType)
 NODE(Type)
 NODE(TypeAlias)
 NODE(TypeList)
+NODE(TypeMangling)
 NODE(TypeMetadata)
 NODE(TypeMetadataAccessFunction)
 NODE(TypeMetadataLazyCache)
 NODE(UncurriedFunctionType)
-NODE(Unknown)
 NODE(Unmanaged)
 NODE(Unowned)
-NODE(UnsafeAddressor)
-NODE(UnsafeMutableAddressor)
+CONTEXT_NODE(UnsafeAddressor)
+CONTEXT_NODE(UnsafeMutableAddressor)
 NODE(ValueWitness)
 NODE(ValueWitnessTable)
-NODE(Variable)
+CONTEXT_NODE(Variable)
 NODE(VariadicTuple)
 NODE(Weak)
-NODE(WillSet)
+CONTEXT_NODE(WillSet)
 NODE(WitnessTableOffset)
 
+#undef CONTEXT_NODE
 #undef NODE