stdlib/public/runtime/Demangle.cpp - third_party/swift - Git at Google

 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the Swift.org open source project
 //
 // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 //===----------------------------------------------------------------------===//

 #include "swift/Runtime/Metadata.h"
 #include "swift/Strings.h"
 #include "Private.h"

 #include <vector>

 #if SWIFT_OBJC_INTEROP
 #include <objc/runtime.h>
 #endif

 using namespace swift;

 // FIXME: This stuff should be merged with the existing logic in
 // include/swift/Reflection/TypeRefBuilder.h as part of the rewrite
 // to change stdlib reflection over to using remote mirrors.

 Demangle::NodePointer
 swift::_swift_buildDemanglingForMetadata(const Metadata *type,
                                          Demangle::Demangler &Dem);

 // Build a demangled type tree for a nominal type.
 static Demangle::NodePointer
 _buildDemanglingForNominalType(const Metadata *type, Demangle::Demangler &Dem) {
   using namespace Demangle;

   const Metadata *parent;
   Node::Kind boundGenericKind;
   const NominalTypeDescriptor *description;

   // Demangle the parent type, if any.
   switch (type->getKind()) {
   case MetadataKind::Class: {
     auto classType = static_cast<const ClassMetadata *>(type);
 #if SWIFT_OBJC_INTEROP
     // Peek through artificial subclasses.
     while (classType->isTypeMetadata() && classType->isArtificialSubclass())
       classType = classType->SuperClass;
 #endif
     parent = classType->getParentType(classType->getDescription());
     boundGenericKind = Node::Kind::BoundGenericClass;
     description = classType->getDescription();
     break;
   }
   case MetadataKind::Enum:
   case MetadataKind::Optional: {
     auto enumType = static_cast<const EnumMetadata *>(type);
     parent = enumType->Parent;
     boundGenericKind = Node::Kind::BoundGenericEnum;
     description = enumType->Description;
     break;
   }
   case MetadataKind::Struct: {
     auto structType = static_cast<const StructMetadata *>(type);
     parent = structType->Parent;
     boundGenericKind = Node::Kind::BoundGenericStructure;
     description = structType->Description;
     break;
   }
   default:
     return nullptr;
   }

   // Demangle the base name.
   auto node = Dem.demangleType(StringRef(description->Name));
   assert(node->getKind() == Node::Kind::Type);

   // Demangle the parent.
   if (parent) {
     auto parentNode = _swift_buildDemanglingForMetadata(parent, Dem);
     if (parentNode->getKind() == Node::Kind::Type)
       parentNode = parentNode->getChild(0);

     auto typeNode = node->getChild(0);
     auto newTypeNode = Dem.createNode(typeNode->getKind());
     newTypeNode->addChild(parentNode, Dem);
     newTypeNode->addChild(typeNode->getChild(1), Dem);

     auto newNode = Dem.createNode(Node::Kind::Type);
     newNode->addChild(newTypeNode, Dem);
     node = newNode;
   }

   // If generic, demangle the type parameters.
   if (description->GenericParams.NumPrimaryParams > 0) {
     auto typeParams = Dem.createNode(Node::Kind::TypeList);
     auto typeBytes = reinterpret_cast<const char *>(type);
     auto genericParam = reinterpret_cast<const Metadata * const *>(
                  typeBytes + sizeof(void*) * description->GenericParams.Offset);
     for (unsigned i = 0, e = description->GenericParams.NumPrimaryParams;
          i < e; ++i, ++genericParam) {
       auto demangling = _swift_buildDemanglingForMetadata(*genericParam, Dem);
       if (demangling == nullptr)
         return nullptr;
       typeParams->addChild(demangling, Dem);
     }

     auto genericNode = Dem.createNode(boundGenericKind);
     genericNode->addChild(node, Dem);
     genericNode->addChild(typeParams, Dem);
     return genericNode;
   }
   return node;
 }

 // Build a demangled type tree for a type.
 Demangle::NodePointer
 swift::_swift_buildDemanglingForMetadata(const Metadata *type,
                                          Demangle::Demangler &Dem) {
   using namespace Demangle;

   switch (type->getKind()) {
   case MetadataKind::Class:
   case MetadataKind::Enum:
   case MetadataKind::Optional:
   case MetadataKind::Struct:
     return _buildDemanglingForNominalType(type, Dem);
   case MetadataKind::ObjCClassWrapper: {
 #if SWIFT_OBJC_INTEROP
     auto objcWrapper = static_cast<const ObjCClassWrapperMetadata *>(type);
     const char *className = class_getName(objcWrapper->getObjCClassObject());

     // ObjC classes mangle as being in the magic "__ObjC" module.
     auto module = Dem.createNode(Node::Kind::Module, "__ObjC");

     auto node = Dem.createNode(Node::Kind::Class);
     node->addChild(module, Dem);
     node->addChild(Dem.createNode(Node::Kind::Identifier,
                                        llvm::StringRef(className)), Dem);

     return node;
 #else
     assert(false && "no ObjC interop");
     return nullptr;
 #endif
   }
   case MetadataKind::ForeignClass: {
     auto foreign = static_cast<const ForeignClassMetadata *>(type);
     return Dem.demangleType(foreign->getName());
   }
   case MetadataKind::Existential: {
     auto exis = static_cast<const ExistentialTypeMetadata *>(type);

     std::vector<const ProtocolDescriptor *> protocols;
     protocols.reserve(exis->Protocols.NumProtocols);
     for (unsigned i = 0, e = exis->Protocols.NumProtocols; i < e; ++i)
       protocols.push_back(exis->Protocols[i]);

     auto type_list = Dem.createNode(Node::Kind::TypeList);
     auto proto_list = Dem.createNode(Node::Kind::ProtocolList);
     proto_list->addChild(type_list, Dem);

     // The protocol descriptors should be pre-sorted since the compiler will
     // only ever make a swift_getExistentialTypeMetadata invocation using
     // its canonical ordering of protocols.

     for (auto *protocol : protocols) {
       // The protocol name is mangled as a type symbol, with the _Tt prefix.
       StringRef ProtoName(protocol->Name);
       NodePointer protocolNode = Dem.demangleSymbol(ProtoName);

       // ObjC protocol names aren't mangled.
       if (!protocolNode) {
         auto module = Dem.createNode(Node::Kind::Module,
                                           MANGLING_MODULE_OBJC);
         auto node = Dem.createNode(Node::Kind::Protocol);
         node->addChild(module, Dem);
         node->addChild(Dem.createNode(Node::Kind::Identifier,
                                         llvm::StringRef(protocol->Name)), Dem);
         auto typeNode = Dem.createNode(Node::Kind::Type);
         typeNode->addChild(node, Dem);
         type_list->addChild(typeNode, Dem);
         continue;
       }

       // FIXME: We have to dig through a ridiculous number of nodes to get
       // to the Protocol node here.
       protocolNode = protocolNode->getChild(0); // Global -> TypeMangling
       protocolNode = protocolNode->getChild(0); // TypeMangling -> Type
       protocolNode = protocolNode->getChild(0); // Type -> ProtocolList
       protocolNode = protocolNode->getChild(0); // ProtocolList -> TypeList
       protocolNode = protocolNode->getChild(0); // TypeList -> Type

       assert(protocolNode->getKind() == Node::Kind::Type);
       assert(protocolNode->getChild(0)->getKind() == Node::Kind::Protocol);
       type_list->addChild(protocolNode, Dem);
     }

     if (auto superclass = exis->getSuperclassConstraint()) {
       // If there is a superclass constraint, we mangle it specially.
       auto result = Dem.createNode(Node::Kind::ProtocolListWithClass);
       auto superclassNode = _swift_buildDemanglingForMetadata(superclass, Dem);

       result->addChild(proto_list, Dem);
       result->addChild(superclassNode, Dem);
       return result;
     }

     if (exis->isClassBounded()) {
       // Check if the class constraint is implied by any of our
       // protocols.
       bool requiresClassImplicit = false;

       for (auto *protocol : protocols) {
         if (protocol->Flags.getClassConstraint()
             == ProtocolClassConstraint::Class)
           requiresClassImplicit = true;
       }

       // If it was implied, we don't do anything special.
       if (requiresClassImplicit)
         return proto_list;

       // If the existential type has an explicit AnyObject constraint,
       // we must mangle it as such.
       auto result = Dem.createNode(Node::Kind::ProtocolListWithAnyObject);
       result->addChild(proto_list, Dem);
       return result;
     }

     // Just a simple composition of protocols.
     return proto_list;
   }
   case MetadataKind::ExistentialMetatype: {
     auto metatype = static_cast<const ExistentialMetatypeMetadata *>(type);
     auto instance = _swift_buildDemanglingForMetadata(metatype->InstanceType,
                                                       Dem);
     auto node = Dem.createNode(Node::Kind::ExistentialMetatype);
     node->addChild(instance, Dem);
     return node;
   }
   case MetadataKind::Function: {
     auto func = static_cast<const FunctionTypeMetadata *>(type);

     Node::Kind kind;
     switch (func->getConvention()) {
     case FunctionMetadataConvention::Swift:
       kind = Node::Kind::FunctionType;
       break;
     case FunctionMetadataConvention::Block:
       kind = Node::Kind::ObjCBlock;
       break;
     case FunctionMetadataConvention::CFunctionPointer:
       kind = Node::Kind::CFunctionPointer;
       break;
     case FunctionMetadataConvention::Thin:
       kind = Node::Kind::ThinFunctionType;
       break;
     }

     std::vector<NodePointer> inputs;
     for (unsigned i = 0, e = func->getNumArguments(); i < e; ++i) {
       auto arg = func->getArguments()[i];
       auto input = _swift_buildDemanglingForMetadata(arg.getPointer(), Dem);
       if (arg.getFlag()) {
         NodePointer inout = Dem.createNode(Node::Kind::InOut);
         inout->addChild(input, Dem);
         input = inout;
       }
       inputs.push_back(input);
     }

     NodePointer totalInput = nullptr;
     if (inputs.size() > 1) {
       auto tuple = Dem.createNode(Node::Kind::Tuple);
       for (auto &input : inputs)
         tuple->addChild(input, Dem);
       totalInput = tuple;
     } else {
       totalInput = inputs.front();
     }

     NodePointer args = Dem.createNode(Node::Kind::ArgumentTuple);
     args->addChild(totalInput, Dem);

     NodePointer resultTy = _swift_buildDemanglingForMetadata(func->ResultType,
                                                              Dem);
     NodePointer result = Dem.createNode(Node::Kind::ReturnType);
     result->addChild(resultTy, Dem);

     auto funcNode = Dem.createNode(kind);
     if (func->throws())
       funcNode->addChild(Dem.createNode(Node::Kind::ThrowsAnnotation), Dem);
     funcNode->addChild(args, Dem);
     funcNode->addChild(result, Dem);
     return funcNode;
   }
   case MetadataKind::Metatype: {
     auto metatype = static_cast<const MetatypeMetadata *>(type);
     auto instance = _swift_buildDemanglingForMetadata(metatype->InstanceType,
                                                       Dem);
     auto typeNode = Dem.createNode(Node::Kind::Type);
     typeNode->addChild(instance, Dem);
     auto node = Dem.createNode(Node::Kind::Metatype);
     node->addChild(typeNode, Dem);
     return node;
   }
   case MetadataKind::Tuple: {
     auto tuple = static_cast<const TupleTypeMetadata *>(type);
     const char *labels = tuple->Labels;
     auto tupleNode = Dem.createNode(Node::Kind::Tuple);
     for (unsigned i = 0, e = tuple->NumElements; i < e; ++i) {
       auto elt = Dem.createNode(Node::Kind::TupleElement);

       // Add a label child if applicable:
       if (labels) {
         // Look for the next space in the labels string.
         if (const char *space = strchr(labels, ' ')) {
           // If there is one, and the label isn't empty, add a label child.
           if (labels != space) {
             auto eltName =
               Dem.createNode(Node::Kind::TupleElementName,
                                   llvm::StringRef(labels, space - labels));
             elt->addChild(eltName, Dem);
           }

           // Skip past the space.
           labels = space + 1;
         }
       }

       // Add the element type child.
       auto eltType =
         _swift_buildDemanglingForMetadata(tuple->getElement(i).Type, Dem);
       elt->addChild(eltType, Dem);

       // Add the completed element to the tuple.
       tupleNode->addChild(elt, Dem);
     }
     return tupleNode;
   }
   case MetadataKind::Opaque:
     // FIXME: Some opaque types do have manglings, but we don't have enough info
     // to figure them out.
   case MetadataKind::HeapLocalVariable:
   case MetadataKind::HeapGenericLocalVariable:
   case MetadataKind::ErrorObject:
     break;
   }
   // Not a type.
   return nullptr;
 }
	//===----------------------------------------------------------------------===//
	//
	// This source file is part of the Swift.org open source project
	//
	// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
	// Licensed under Apache License v2.0 with Runtime Library Exception
	//
	// See https://swift.org/LICENSE.txt for license information
	// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
	//
	//===----------------------------------------------------------------------===//

	#include "swift/Runtime/Metadata.h"
	#include "swift/Strings.h"
	#include "Private.h"

	#include <vector>

	#if SWIFT_OBJC_INTEROP
	#include <objc/runtime.h>
	#endif

	using namespace swift;

	// FIXME: This stuff should be merged with the existing logic in
	// include/swift/Reflection/TypeRefBuilder.h as part of the rewrite
	// to change stdlib reflection over to using remote mirrors.

	Demangle::NodePointer
	swift::_swift_buildDemanglingForMetadata(const Metadata *type,
	Demangle::Demangler &Dem);

	// Build a demangled type tree for a nominal type.
	static Demangle::NodePointer
	_buildDemanglingForNominalType(const Metadata *type, Demangle::Demangler &Dem) {
	using namespace Demangle;

	const Metadata *parent;
	Node::Kind boundGenericKind;
	const NominalTypeDescriptor *description;

	// Demangle the parent type, if any.
	switch (type->getKind()) {
	case MetadataKind::Class: {
	auto classType = static_cast<const ClassMetadata *>(type);
	#if SWIFT_OBJC_INTEROP
	// Peek through artificial subclasses.
	while (classType->isTypeMetadata() && classType->isArtificialSubclass())
	classType = classType->SuperClass;
	#endif
	parent = classType->getParentType(classType->getDescription());
	boundGenericKind = Node::Kind::BoundGenericClass;
	description = classType->getDescription();
	break;
	}
	case MetadataKind::Enum:
	case MetadataKind::Optional: {
	auto enumType = static_cast<const EnumMetadata *>(type);
	parent = enumType->Parent;
	boundGenericKind = Node::Kind::BoundGenericEnum;
	description = enumType->Description;
	break;
	}
	case MetadataKind::Struct: {
	auto structType = static_cast<const StructMetadata *>(type);
	parent = structType->Parent;
	boundGenericKind = Node::Kind::BoundGenericStructure;
	description = structType->Description;
	break;
	}
	default:
	return nullptr;
	}

	// Demangle the base name.
	auto node = Dem.demangleType(StringRef(description->Name));
	assert(node->getKind() == Node::Kind::Type);

	// Demangle the parent.
	if (parent) {
	auto parentNode = _swift_buildDemanglingForMetadata(parent, Dem);
	if (parentNode->getKind() == Node::Kind::Type)
	parentNode = parentNode->getChild(0);

	auto typeNode = node->getChild(0);
	auto newTypeNode = Dem.createNode(typeNode->getKind());
	newTypeNode->addChild(parentNode, Dem);
	newTypeNode->addChild(typeNode->getChild(1), Dem);

	auto newNode = Dem.createNode(Node::Kind::Type);
	newNode->addChild(newTypeNode, Dem);
	node = newNode;
	}

	// If generic, demangle the type parameters.
	if (description->GenericParams.NumPrimaryParams > 0) {
	auto typeParams = Dem.createNode(Node::Kind::TypeList);
	auto typeBytes = reinterpret_cast<const char *>(type);
	auto genericParam = reinterpret_cast<const Metadata * const *>(
	typeBytes + sizeof(void) description->GenericParams.Offset);
	for (unsigned i = 0, e = description->GenericParams.NumPrimaryParams;
	i < e; ++i, ++genericParam) {
	auto demangling = _swift_buildDemanglingForMetadata(*genericParam, Dem);
	if (demangling == nullptr)
	return nullptr;
	typeParams->addChild(demangling, Dem);
	}

	auto genericNode = Dem.createNode(boundGenericKind);
	genericNode->addChild(node, Dem);
	genericNode->addChild(typeParams, Dem);
	return genericNode;
	}
	return node;
	}

	// Build a demangled type tree for a type.
	Demangle::NodePointer
	swift::_swift_buildDemanglingForMetadata(const Metadata *type,
	Demangle::Demangler &Dem) {
	using namespace Demangle;

	switch (type->getKind()) {
	case MetadataKind::Class:
	case MetadataKind::Enum:
	case MetadataKind::Optional:
	case MetadataKind::Struct:
	return _buildDemanglingForNominalType(type, Dem);
	case MetadataKind::ObjCClassWrapper: {
	#if SWIFT_OBJC_INTEROP
	auto objcWrapper = static_cast<const ObjCClassWrapperMetadata *>(type);
	const char *className = class_getName(objcWrapper->getObjCClassObject());

	// ObjC classes mangle as being in the magic "__ObjC" module.
	auto module = Dem.createNode(Node::Kind::Module, "__ObjC");

	auto node = Dem.createNode(Node::Kind::Class);
	node->addChild(module, Dem);
	node->addChild(Dem.createNode(Node::Kind::Identifier,
	llvm::StringRef(className)), Dem);

	return node;
	#else
	assert(false && "no ObjC interop");
	return nullptr;
	#endif
	}
	case MetadataKind::ForeignClass: {
	auto foreign = static_cast<const ForeignClassMetadata *>(type);
	return Dem.demangleType(foreign->getName());
	}
	case MetadataKind::Existential: {
	auto exis = static_cast<const ExistentialTypeMetadata *>(type);

	std::vector<const ProtocolDescriptor *> protocols;
	protocols.reserve(exis->Protocols.NumProtocols);
	for (unsigned i = 0, e = exis->Protocols.NumProtocols; i < e; ++i)
	protocols.push_back(exis->Protocols[i]);

	auto type_list = Dem.createNode(Node::Kind::TypeList);
	auto proto_list = Dem.createNode(Node::Kind::ProtocolList);
	proto_list->addChild(type_list, Dem);

	// The protocol descriptors should be pre-sorted since the compiler will
	// only ever make a swift_getExistentialTypeMetadata invocation using
	// its canonical ordering of protocols.

	for (auto *protocol : protocols) {
	// The protocol name is mangled as a type symbol, with the _Tt prefix.
	StringRef ProtoName(protocol->Name);
	NodePointer protocolNode = Dem.demangleSymbol(ProtoName);

	// ObjC protocol names aren't mangled.
	if (!protocolNode) {
	auto module = Dem.createNode(Node::Kind::Module,
	MANGLING_MODULE_OBJC);
	auto node = Dem.createNode(Node::Kind::Protocol);
	node->addChild(module, Dem);
	node->addChild(Dem.createNode(Node::Kind::Identifier,
	llvm::StringRef(protocol->Name)), Dem);
	auto typeNode = Dem.createNode(Node::Kind::Type);
	typeNode->addChild(node, Dem);
	type_list->addChild(typeNode, Dem);
	continue;
	}

	// FIXME: We have to dig through a ridiculous number of nodes to get
	// to the Protocol node here.
	protocolNode = protocolNode->getChild(0); // Global -> TypeMangling
	protocolNode = protocolNode->getChild(0); // TypeMangling -> Type
	protocolNode = protocolNode->getChild(0); // Type -> ProtocolList
	protocolNode = protocolNode->getChild(0); // ProtocolList -> TypeList
	protocolNode = protocolNode->getChild(0); // TypeList -> Type

	assert(protocolNode->getKind() == Node::Kind::Type);
	assert(protocolNode->getChild(0)->getKind() == Node::Kind::Protocol);
	type_list->addChild(protocolNode, Dem);
	}

	if (auto superclass = exis->getSuperclassConstraint()) {
	// If there is a superclass constraint, we mangle it specially.
	auto result = Dem.createNode(Node::Kind::ProtocolListWithClass);
	auto superclassNode = _swift_buildDemanglingForMetadata(superclass, Dem);

	result->addChild(proto_list, Dem);
	result->addChild(superclassNode, Dem);
	return result;
	}

	if (exis->isClassBounded()) {
	// Check if the class constraint is implied by any of our
	// protocols.
	bool requiresClassImplicit = false;

	for (auto *protocol : protocols) {
	if (protocol->Flags.getClassConstraint()
	== ProtocolClassConstraint::Class)
	requiresClassImplicit = true;
	}

	// If it was implied, we don't do anything special.
	if (requiresClassImplicit)
	return proto_list;

	// If the existential type has an explicit AnyObject constraint,
	// we must mangle it as such.
	auto result = Dem.createNode(Node::Kind::ProtocolListWithAnyObject);
	result->addChild(proto_list, Dem);
	return result;
	}

	// Just a simple composition of protocols.
	return proto_list;
	}
	case MetadataKind::ExistentialMetatype: {
	auto metatype = static_cast<const ExistentialMetatypeMetadata *>(type);
	auto instance = _swift_buildDemanglingForMetadata(metatype->InstanceType,
	Dem);
	auto node = Dem.createNode(Node::Kind::ExistentialMetatype);
	node->addChild(instance, Dem);
	return node;
	}
	case MetadataKind::Function: {
	auto func = static_cast<const FunctionTypeMetadata *>(type);

	Node::Kind kind;
	switch (func->getConvention()) {
	case FunctionMetadataConvention::Swift:
	kind = Node::Kind::FunctionType;
	break;
	case FunctionMetadataConvention::Block:
	kind = Node::Kind::ObjCBlock;
	break;
	case FunctionMetadataConvention::CFunctionPointer:
	kind = Node::Kind::CFunctionPointer;
	break;
	case FunctionMetadataConvention::Thin:
	kind = Node::Kind::ThinFunctionType;
	break;
	}

	std::vector<NodePointer> inputs;
	for (unsigned i = 0, e = func->getNumArguments(); i < e; ++i) {
	auto arg = func->getArguments()[i];
	auto input = _swift_buildDemanglingForMetadata(arg.getPointer(), Dem);
	if (arg.getFlag()) {
	NodePointer inout = Dem.createNode(Node::Kind::InOut);
	inout->addChild(input, Dem);
	input = inout;
	}
	inputs.push_back(input);
	}

	NodePointer totalInput = nullptr;
	if (inputs.size() > 1) {
	auto tuple = Dem.createNode(Node::Kind::Tuple);
	for (auto &input : inputs)
	tuple->addChild(input, Dem);
	totalInput = tuple;
	} else {
	totalInput = inputs.front();
	}

	NodePointer args = Dem.createNode(Node::Kind::ArgumentTuple);
	args->addChild(totalInput, Dem);

	NodePointer resultTy = _swift_buildDemanglingForMetadata(func->ResultType,
	Dem);
	NodePointer result = Dem.createNode(Node::Kind::ReturnType);
	result->addChild(resultTy, Dem);

	auto funcNode = Dem.createNode(kind);
	if (func->throws())
	funcNode->addChild(Dem.createNode(Node::Kind::ThrowsAnnotation), Dem);
	funcNode->addChild(args, Dem);
	funcNode->addChild(result, Dem);
	return funcNode;
	}
	case MetadataKind::Metatype: {
	auto metatype = static_cast<const MetatypeMetadata *>(type);
	auto instance = _swift_buildDemanglingForMetadata(metatype->InstanceType,
	Dem);
	auto typeNode = Dem.createNode(Node::Kind::Type);
	typeNode->addChild(instance, Dem);
	auto node = Dem.createNode(Node::Kind::Metatype);
	node->addChild(typeNode, Dem);
	return node;
	}
	case MetadataKind::Tuple: {
	auto tuple = static_cast<const TupleTypeMetadata *>(type);
	const char *labels = tuple->Labels;
	auto tupleNode = Dem.createNode(Node::Kind::Tuple);
	for (unsigned i = 0, e = tuple->NumElements; i < e; ++i) {
	auto elt = Dem.createNode(Node::Kind::TupleElement);

	// Add a label child if applicable:
	if (labels) {
	// Look for the next space in the labels string.
	if (const char *space = strchr(labels, ' ')) {
	// If there is one, and the label isn't empty, add a label child.
	if (labels != space) {
	auto eltName =
	Dem.createNode(Node::Kind::TupleElementName,
	llvm::StringRef(labels, space - labels));
	elt->addChild(eltName, Dem);
	}

	// Skip past the space.
	labels = space + 1;
	}
	}

	// Add the element type child.
	auto eltType =
	_swift_buildDemanglingForMetadata(tuple->getElement(i).Type, Dem);
	elt->addChild(eltType, Dem);

	// Add the completed element to the tuple.
	tupleNode->addChild(elt, Dem);
	}
	return tupleNode;
	}
	case MetadataKind::Opaque:
	// FIXME: Some opaque types do have manglings, but we don't have enough info
	// to figure them out.
	case MetadataKind::HeapLocalVariable:
	case MetadataKind::HeapGenericLocalVariable:
	case MetadataKind::ErrorObject:
	break;
	}
	// Not a type.
	return nullptr;
	}