7 files changed, 6690 insertions, 0 deletions

diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
index dfd40cba6..89a381587 100644
--- a/externals/CMakeLists.txt
+++ b/externals/CMakeLists.txt
@@ -154,3 +154,7 @@ endif()
 if (YUZU_USE_EXTERNAL_VULKAN_HEADERS)
     add_subdirectory(Vulkan-Headers EXCLUDE_FROM_ALL)
 endif()
+
+add_library(demangle STATIC)
+target_include_directories(demangle PUBLIC ./demangle)
+target_sources(demangle PRIVATE demangle/ItaniumDemangle.cpp)
diff --git a/externals/demangle/Demangle.h b/externals/demangle/Demangle.h
new file mode 100644
index 000000000..5b673e4e1
--- /dev/null
+++ b/externals/demangle/Demangle.h
@@ -0,0 +1,104 @@
+//===--- Demangle.h ---------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEMANGLE_DEMANGLE_H
+#define LLVM_DEMANGLE_DEMANGLE_H
+
+#include <cstddef>
+#include <string>
+
+namespace llvm {
+/// This is a llvm local version of __cxa_demangle. Other than the name and
+/// being in the llvm namespace it is identical.
+///
+/// The mangled_name is demangled into buf and returned. If the buffer is not
+/// large enough, realloc is used to expand it.
+///
+/// The *status will be set to a value from the following enumeration
+enum : int {
+  demangle_unknown_error = -4,
+  demangle_invalid_args = -3,
+  demangle_invalid_mangled_name = -2,
+  demangle_memory_alloc_failure = -1,
+  demangle_success = 0,
+};
+
+char *itaniumDemangle(const char *mangled_name, char *buf, size_t *n,
+                      int *status);
+
+
+enum MSDemangleFlags {
+  MSDF_None = 0,
+  MSDF_DumpBackrefs = 1 << 0,
+  MSDF_NoAccessSpecifier = 1 << 1,
+  MSDF_NoCallingConvention = 1 << 2,
+  MSDF_NoReturnType = 1 << 3,
+  MSDF_NoMemberType = 1 << 4,
+};
+char *microsoftDemangle(const char *mangled_name, char *buf, size_t *n,
+                        int *status, MSDemangleFlags Flags = MSDF_None);
+
+/// "Partial" demangler. This supports demangling a string into an AST
+/// (typically an intermediate stage in itaniumDemangle) and querying certain
+/// properties or partially printing the demangled name.
+struct ItaniumPartialDemangler {
+  ItaniumPartialDemangler();
+
+  ItaniumPartialDemangler(ItaniumPartialDemangler &&Other);
+  ItaniumPartialDemangler &operator=(ItaniumPartialDemangler &&Other);
+
+  /// Demangle into an AST. Subsequent calls to the rest of the member functions
+  /// implicitly operate on the AST this produces.
+  /// \return true on error, false otherwise
+  bool partialDemangle(const char *MangledName);
+
+  /// Just print the entire mangled name into Buf. Buf and N behave like the
+  /// second and third parameters to itaniumDemangle.
+  char *finishDemangle(char *Buf, size_t *N) const;
+
+  /// Get the base name of a function. This doesn't include trailing template
+  /// arguments, ie for "a::b<int>" this function returns "b".
+  char *getFunctionBaseName(char *Buf, size_t *N) const;
+
+  /// Get the context name for a function. For "a::b::c", this function returns
+  /// "a::b".
+  char *getFunctionDeclContextName(char *Buf, size_t *N) const;
+
+  /// Get the entire name of this function.
+  char *getFunctionName(char *Buf, size_t *N) const;
+
+  /// Get the parameters for this function.
+  char *getFunctionParameters(char *Buf, size_t *N) const;
+  char *getFunctionReturnType(char *Buf, size_t *N) const;
+
+  /// If this function has any any cv or reference qualifiers. These imply that
+  /// the function is a non-static member function.
+  bool hasFunctionQualifiers() const;
+
+  /// If this symbol describes a constructor or destructor.
+  bool isCtorOrDtor() const;
+
+  /// If this symbol describes a function.
+  bool isFunction() const;
+
+  /// If this symbol describes a variable.
+  bool isData() const;
+
+  /// If this symbol is a <special-name>. These are generally implicitly
+  /// generated by the implementation, such as vtables and typeinfo names.
+  bool isSpecialName() const;
+
+  ~ItaniumPartialDemangler();
+private:
+  void *RootNode;
+  void *Context;
+};
+} // namespace llvm
+
+#endif
diff --git a/externals/demangle/DemangleConfig.h b/externals/demangle/DemangleConfig.h
new file mode 100644
index 000000000..a8aef9df1
--- /dev/null
+++ b/externals/demangle/DemangleConfig.h
@@ -0,0 +1,93 @@
+//===--- DemangleConfig.h ---------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a variety of feature test macros copied from
+// include/llvm/Support/Compiler.h so that LLVMDemangle does not need to take
+// a dependency on LLVMSupport.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEMANGLE_COMPILER_H
+#define LLVM_DEMANGLE_COMPILER_H
+
+#ifndef __has_feature
+#define __has_feature(x) 0
+#endif
+
+#ifndef __has_cpp_attribute
+#define __has_cpp_attribute(x) 0
+#endif
+
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#ifndef DEMANGLE_GNUC_PREREQ
+#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
+#define DEMANGLE_GNUC_PREREQ(maj, min, patch)                           \
+  ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >=          \
+   ((maj) << 20) + ((min) << 10) + (patch))
+#elif defined(__GNUC__) && defined(__GNUC_MINOR__)
+#define DEMANGLE_GNUC_PREREQ(maj, min, patch)                           \
+  ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
+#else
+#define DEMANGLE_GNUC_PREREQ(maj, min, patch) 0
+#endif
+#endif
+
+#if __has_attribute(used) || DEMANGLE_GNUC_PREREQ(3, 1, 0)
+#define DEMANGLE_ATTRIBUTE_USED __attribute__((__used__))
+#else
+#define DEMANGLE_ATTRIBUTE_USED
+#endif
+
+#if __has_builtin(__builtin_unreachable) || DEMANGLE_GNUC_PREREQ(4, 5, 0)
+#define DEMANGLE_UNREACHABLE __builtin_unreachable()
+#elif defined(_MSC_VER)
+#define DEMANGLE_UNREACHABLE __assume(false)
+#else
+#define DEMANGLE_UNREACHABLE
+#endif
+
+#if __has_attribute(noinline) || DEMANGLE_GNUC_PREREQ(3, 4, 0)
+#define DEMANGLE_ATTRIBUTE_NOINLINE __attribute__((noinline))
+#elif defined(_MSC_VER)
+#define DEMANGLE_ATTRIBUTE_NOINLINE __declspec(noinline)
+#else
+#define DEMANGLE_ATTRIBUTE_NOINLINE
+#endif
+
+#if !defined(NDEBUG)
+#define DEMANGLE_DUMP_METHOD DEMANGLE_ATTRIBUTE_NOINLINE DEMANGLE_ATTRIBUTE_USED
+#else
+#define DEMANGLE_DUMP_METHOD DEMANGLE_ATTRIBUTE_NOINLINE
+#endif
+
+#if __cplusplus > 201402L && __has_cpp_attribute(fallthrough)
+#define DEMANGLE_FALLTHROUGH [[fallthrough]]
+#elif __has_cpp_attribute(gnu::fallthrough)
+#define DEMANGLE_FALLTHROUGH [[gnu::fallthrough]]
+#elif !__cplusplus
+// Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
+// error when __has_cpp_attribute is given a scoped attribute in C mode.
+#define DEMANGLE_FALLTHROUGH
+#elif __has_cpp_attribute(clang::fallthrough)
+#define DEMANGLE_FALLTHROUGH [[clang::fallthrough]]
+#else
+#define DEMANGLE_FALLTHROUGH
+#endif
+
+#define DEMANGLE_NAMESPACE_BEGIN namespace llvm { namespace itanium_demangle {
+#define DEMANGLE_NAMESPACE_END } }
+
+#endif
diff --git a/externals/demangle/ItaniumDemangle.cpp b/externals/demangle/ItaniumDemangle.cpp
new file mode 100644
index 000000000..5e078e3e2
--- /dev/null
+++ b/externals/demangle/ItaniumDemangle.cpp
@@ -0,0 +1,588 @@
+//===------------------------- ItaniumDemangle.cpp ------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// FIXME: (possibly) incomplete list of features that clang mangles that this
+// file does not yet support:
+//   - C++ modules TS
+
+#include "Demangle.h"
+#include "ItaniumDemangle.h"
+
+#include <cassert>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <numeric>
+#include <utility>
+#include <vector>
+
+using namespace llvm;
+using namespace llvm::itanium_demangle;
+
+constexpr const char *itanium_demangle::FloatData<float>::spec;
+constexpr const char *itanium_demangle::FloatData<double>::spec;
+constexpr const char *itanium_demangle::FloatData<long double>::spec;
+
+// <discriminator> := _ <non-negative number>      # when number < 10
+//                 := __ <non-negative number> _   # when number >= 10
+//  extension      := decimal-digit+               # at the end of string
+const char *itanium_demangle::parse_discriminator(const char *first,
+                                                  const char *last) {
+  // parse but ignore discriminator
+  if (first != last) {
+    if (*first == '_') {
+      const char *t1 = first + 1;
+      if (t1 != last) {
+        if (std::isdigit(*t1))
+          first = t1 + 1;
+        else if (*t1 == '_') {
+          for (++t1; t1 != last && std::isdigit(*t1); ++t1)
+            ;
+          if (t1 != last && *t1 == '_')
+            first = t1 + 1;
+        }
+      }
+    } else if (std::isdigit(*first)) {
+      const char *t1 = first + 1;
+      for (; t1 != last && std::isdigit(*t1); ++t1)
+        ;
+      if (t1 == last)
+        first = last;
+    }
+  }
+  return first;
+}
+
+#ifndef NDEBUG
+namespace {
+struct DumpVisitor {
+  unsigned Depth = 0;
+  bool PendingNewline = false;
+
+  template<typename NodeT> static constexpr bool wantsNewline(const NodeT *) {
+    return true;
+  }
+  static bool wantsNewline(NodeArray A) { return !A.empty(); }
+  static constexpr bool wantsNewline(...) { return false; }
+
+  template<typename ...Ts> static bool anyWantNewline(Ts ...Vs) {
+    for (bool B : {wantsNewline(Vs)...})
+      if (B)
+        return true;
+    return false;
+  }
+
+  void printStr(const char *S) { fprintf(stderr, "%s", S); }
+  void print(StringView SV) {
+    fprintf(stderr, "\"%.*s\"", (int)SV.size(), SV.begin());
+  }
+  void print(const Node *N) {
+    if (N)
+      N->visit(std::ref(*this));
+    else
+      printStr("<null>");
+  }
+  void print(NodeOrString NS) {
+    if (NS.isNode())
+      print(NS.asNode());
+    else if (NS.isString())
+      print(NS.asString());
+    else
+      printStr("NodeOrString()");
+  }
+  void print(NodeArray A) {
+    ++Depth;
+    printStr("{");
+    bool First = true;
+    for (const Node *N : A) {
+      if (First)
+        print(N);
+      else
+        printWithComma(N);
+      First = false;
+    }
+    printStr("}");
+    --Depth;
+  }
+
+  // Overload used when T is exactly 'bool', not merely convertible to 'bool'.
+  void print(bool B) { printStr(B ? "true" : "false"); }
+
+  template <class T>
+  typename std::enable_if<std::is_unsigned<T>::value>::type print(T N) {
+    fprintf(stderr, "%llu", (unsigned long long)N);
+  }
+
+  template <class T>
+  typename std::enable_if<std::is_signed<T>::value>::type print(T N) {
+    fprintf(stderr, "%lld", (long long)N);
+  }
+
+  void print(ReferenceKind RK) {
+    switch (RK) {
+    case ReferenceKind::LValue:
+      return printStr("ReferenceKind::LValue");
+    case ReferenceKind::RValue:
+      return printStr("ReferenceKind::RValue");
+    }
+  }
+  void print(FunctionRefQual RQ) {
+    switch (RQ) {
+    case FunctionRefQual::FrefQualNone:
+      return printStr("FunctionRefQual::FrefQualNone");
+    case FunctionRefQual::FrefQualLValue:
+      return printStr("FunctionRefQual::FrefQualLValue");
+    case FunctionRefQual::FrefQualRValue:
+      return printStr("FunctionRefQual::FrefQualRValue");
+    }
+  }
+  void print(Qualifiers Qs) {
+    if (!Qs) return printStr("QualNone");
+    struct QualName { Qualifiers Q; const char *Name; } Names[] = {
+      {QualConst, "QualConst"},
+      {QualVolatile, "QualVolatile"},
+      {QualRestrict, "QualRestrict"},
+    };
+    for (QualName Name : Names) {
+      if (Qs & Name.Q) {
+        printStr(Name.Name);
+        Qs = Qualifiers(Qs & ~Name.Q);
+        if (Qs) printStr(" | ");
+      }
+    }
+  }
+  void print(SpecialSubKind SSK) {
+    switch (SSK) {
+    case SpecialSubKind::allocator:
+      return printStr("SpecialSubKind::allocator");
+    case SpecialSubKind::basic_string:
+      return printStr("SpecialSubKind::basic_string");
+    case SpecialSubKind::string:
+      return printStr("SpecialSubKind::string");
+    case SpecialSubKind::istream:
+      return printStr("SpecialSubKind::istream");
+    case SpecialSubKind::ostream:
+      return printStr("SpecialSubKind::ostream");
+    case SpecialSubKind::iostream:
+      return printStr("SpecialSubKind::iostream");
+    }
+  }
+  void print(TemplateParamKind TPK) {
+    switch (TPK) {
+    case TemplateParamKind::Type:
+      return printStr("TemplateParamKind::Type");
+    case TemplateParamKind::NonType:
+      return printStr("TemplateParamKind::NonType");
+    case TemplateParamKind::Template:
+      return printStr("TemplateParamKind::Template");
+    }
+  }
+
+  void newLine() {
+    printStr("\n");
+    for (unsigned I = 0; I != Depth; ++I)
+      printStr(" ");
+    PendingNewline = false;
+  }
+
+  template<typename T> void printWithPendingNewline(T V) {
+    print(V);
+    if (wantsNewline(V))
+      PendingNewline = true;
+  }
+
+  template<typename T> void printWithComma(T V) {
+    if (PendingNewline || wantsNewline(V)) {
+      printStr(",");
+      newLine();
+    } else {
+      printStr(", ");
+    }
+
+    printWithPendingNewline(V);
+  }
+
+  struct CtorArgPrinter {
+    DumpVisitor &Visitor;
+
+    template<typename T, typename ...Rest> void operator()(T V, Rest ...Vs) {
+      if (Visitor.anyWantNewline(V, Vs...))
+        Visitor.newLine();
+      Visitor.printWithPendingNewline(V);
+      int PrintInOrder[] = { (Visitor.printWithComma(Vs), 0)..., 0 };
+      (void)PrintInOrder;
+    }
+  };
+
+  template<typename NodeT> void operator()(const NodeT *Node) {
+    Depth += 2;
+    fprintf(stderr, "%s(", itanium_demangle::NodeKind<NodeT>::name());
+    Node->match(CtorArgPrinter{*this});
+    fprintf(stderr, ")");
+    Depth -= 2;
+  }
+
+  void operator()(const ForwardTemplateReference *Node) {
+    Depth += 2;
+    fprintf(stderr, "ForwardTemplateReference(");
+    if (Node->Ref && !Node->Printing) {
+      Node->Printing = true;
+      CtorArgPrinter{*this}(Node->Ref);
+      Node->Printing = false;
+    } else {
+      CtorArgPrinter{*this}(Node->Index);
+    }
+    fprintf(stderr, ")");
+    Depth -= 2;
+  }
+};
+}
+
+void itanium_demangle::Node::dump() const {
+  DumpVisitor V;
+  visit(std::ref(V));
+  V.newLine();
+}
+#endif
+
+namespace {
+class BumpPointerAllocator {
+  struct BlockMeta {
+    BlockMeta* Next;
+    size_t Current;
+  };
+
+  static constexpr size_t AllocSize = 4096;
+  static constexpr size_t UsableAllocSize = AllocSize - sizeof(BlockMeta);
+
+  alignas(long double) char InitialBuffer[AllocSize];
+  BlockMeta* BlockList = nullptr;
+
+  void grow() {
+    char* NewMeta = static_cast<char *>(std::malloc(AllocSize));
+    if (NewMeta == nullptr)
+      std::terminate();
+    BlockList = new (NewMeta) BlockMeta{BlockList, 0};
+  }
+
+  void* allocateMassive(size_t NBytes) {
+    NBytes += sizeof(BlockMeta);
+    BlockMeta* NewMeta = reinterpret_cast<BlockMeta*>(std::malloc(NBytes));
+    if (NewMeta == nullptr)
+      std::terminate();
+    BlockList->Next = new (NewMeta) BlockMeta{BlockList->Next, 0};
+    return static_cast<void*>(NewMeta + 1);
+  }
+
+public:
+  BumpPointerAllocator()
+      : BlockList(new (InitialBuffer) BlockMeta{nullptr, 0}) {}
+
+  void* allocate(size_t N) {
+    N = (N + 15u) & ~15u;
+    if (N + BlockList->Current >= UsableAllocSize) {
+      if (N > UsableAllocSize)
+        return allocateMassive(N);
+      grow();
+    }
+    BlockList->Current += N;
+    return static_cast<void*>(reinterpret_cast<char*>(BlockList + 1) +
+                              BlockList->Current - N);
+  }
+
+  void reset() {
+    while (BlockList) {
+      BlockMeta* Tmp = BlockList;
+      BlockList = BlockList->Next;
+      if (reinterpret_cast<char*>(Tmp) != InitialBuffer)
+        std::free(Tmp);
+    }
+    BlockList = new (InitialBuffer) BlockMeta{nullptr, 0};
+  }
+
+  ~BumpPointerAllocator() { reset(); }
+};
+
+class DefaultAllocator {
+  BumpPointerAllocator Alloc;
+
+public:
+  void reset() { Alloc.reset(); }
+
+  template<typename T, typename ...Args> T *makeNode(Args &&...args) {
+    return new (Alloc.allocate(sizeof(T)))
+        T(std::forward<Args>(args)...);
+  }
+
+  void *allocateNodeArray(size_t sz) {
+    return Alloc.allocate(sizeof(Node *) * sz);
+  }
+};
+}  // unnamed namespace
+
+//===----------------------------------------------------------------------===//
+// Code beyond this point should not be synchronized with libc++abi.
+//===----------------------------------------------------------------------===//
+
+using Demangler = itanium_demangle::ManglingParser<DefaultAllocator>;
+
+char *llvm::itaniumDemangle(const char *MangledName, char *Buf,
+                            size_t *N, int *Status) {
+  if (MangledName == nullptr || (Buf != nullptr && N == nullptr)) {
+    if (Status)
+      *Status = demangle_invalid_args;
+    return nullptr;
+  }
+
+  int InternalStatus = demangle_success;
+  Demangler Parser(MangledName, MangledName + std::strlen(MangledName));
+  OutputStream S;
+
+  Node *AST = Parser.parse();
+
+  if (AST == nullptr)
+    InternalStatus = demangle_invalid_mangled_name;
+  else if (!initializeOutputStream(Buf, N, S, 1024))
+    InternalStatus = demangle_memory_alloc_failure;
+  else {
+    assert(Parser.ForwardTemplateRefs.empty());
+    AST->print(S);
+    S += '\0';
+    if (N != nullptr)
+      *N = S.getCurrentPosition();
+    Buf = S.getBuffer();
+  }
+
+  if (Status)
+    *Status = InternalStatus;
+  return InternalStatus == demangle_success ? Buf : nullptr;
+}
+
+ItaniumPartialDemangler::ItaniumPartialDemangler()
+    : RootNode(nullptr), Context(new Demangler{nullptr, nullptr}) {}
+
+ItaniumPartialDemangler::~ItaniumPartialDemangler() {
+  delete static_cast<Demangler *>(Context);
+}
+
+ItaniumPartialDemangler::ItaniumPartialDemangler(
+    ItaniumPartialDemangler &&Other)
+    : RootNode(Other.RootNode), Context(Other.Context) {
+  Other.Context = Other.RootNode = nullptr;
+}
+
+ItaniumPartialDemangler &ItaniumPartialDemangler::
+operator=(ItaniumPartialDemangler &&Other) {
+  std::swap(RootNode, Other.RootNode);
+  std::swap(Context, Other.Context);
+  return *this;
+}
+
+// Demangle MangledName into an AST, storing it into this->RootNode.
+bool ItaniumPartialDemangler::partialDemangle(const char *MangledName) {
+  Demangler *Parser = static_cast<Demangler *>(Context);
+  size_t Len = std::strlen(MangledName);
+  Parser->reset(MangledName, MangledName + Len);
+  RootNode = Parser->parse();
+  return RootNode == nullptr;
+}
+
+static char *printNode(const Node *RootNode, char *Buf, size_t *N) {
+  OutputStream S;
+  if (!initializeOutputStream(Buf, N, S, 128))
+    return nullptr;
+  RootNode->print(S);
+  S += '\0';
+  if (N != nullptr)
+    *N = S.getCurrentPosition();
+  return S.getBuffer();
+}
+
+char *ItaniumPartialDemangler::getFunctionBaseName(char *Buf, size_t *N) const {
+  if (!isFunction())
+    return nullptr;
+
+  const Node *Name = static_cast<const FunctionEncoding *>(RootNode)->getName();
+
+  while (true) {
+    switch (Name->getKind()) {
+    case Node::KAbiTagAttr:
+      Name = static_cast<const AbiTagAttr *>(Name)->Base;
+      continue;
+    case Node::KStdQualifiedName:
+      Name = static_cast<const StdQualifiedName *>(Name)->Child;
+      continue;
+    case Node::KNestedName:
+      Name = static_cast<const NestedName *>(Name)->Name;
+      continue;
+    case Node::KLocalName:
+      Name = static_cast<const LocalName *>(Name)->Entity;
+      continue;
+    case Node::KNameWithTemplateArgs:
+      Name = static_cast<const NameWithTemplateArgs *>(Name)->Name;
+      continue;
+    default:
+      return printNode(Name, Buf, N);
+    }
+  }
+}
+
+char *ItaniumPartialDemangler::getFunctionDeclContextName(char *Buf,
+                                                          size_t *N) const {
+  if (!isFunction())
+    return nullptr;
+  const Node *Name = static_cast<const FunctionEncoding *>(RootNode)->getName();
+
+  OutputStream S;
+  if (!initializeOutputStream(Buf, N, S, 128))
+    return nullptr;
+
+ KeepGoingLocalFunction:
+  while (true) {
+    if (Name->getKind() == Node::KAbiTagAttr) {
+      Name = static_cast<const AbiTagAttr *>(Name)->Base;
+      continue;
+    }
+    if (Name->getKind() == Node::KNameWithTemplateArgs) {
+      Name = static_cast<const NameWithTemplateArgs *>(Name)->Name;
+      continue;
+    }
+    break;
+  }
+
+  switch (Name->getKind()) {
+  case Node::KStdQualifiedName:
+    S += "std";
+    break;
+  case Node::KNestedName:
+    static_cast<const NestedName *>(Name)->Qual->print(S);
+    break;
+  case Node::KLocalName: {
+    auto *LN = static_cast<const LocalName *>(Name);
+    LN->Encoding->print(S);
+    S += "::";
+    Name = LN->Entity;
+    goto KeepGoingLocalFunction;
+  }
+  default:
+    break;
+  }
+  S += '\0';
+  if (N != nullptr)
+    *N = S.getCurrentPosition();
+  return S.getBuffer();
+}
+
+char *ItaniumPartialDemangler::getFunctionName(char *Buf, size_t *N) const {
+  if (!isFunction())
+    return nullptr;
+  auto *Name = static_cast<FunctionEncoding *>(RootNode)->getName();
+  return printNode(Name, Buf, N);
+}
+
+char *ItaniumPartialDemangler::getFunctionParameters(char *Buf,
+                                                     size_t *N) const {
+  if (!isFunction())
+    return nullptr;
+  NodeArray Params = static_cast<FunctionEncoding *>(RootNode)->getParams();
+
+  OutputStream S;
+  if (!initializeOutputStream(Buf, N, S, 128))
+    return nullptr;
+
+  S += '(';
+  Params.printWithComma(S);
+  S += ')';
+  S += '\0';
+  if (N != nullptr)
+    *N = S.getCurrentPosition();
+  return S.getBuffer();
+}
+
+char *ItaniumPartialDemangler::getFunctionReturnType(
+    char *Buf, size_t *N) const {
+  if (!isFunction())
+    return nullptr;
+
+  OutputStream S;
+  if (!initializeOutputStream(Buf, N, S, 128))
+    return nullptr;
+
+  if (const Node *Ret =
+          static_cast<const FunctionEncoding *>(RootNode)->getReturnType())
+    Ret->print(S);
+
+  S += '\0';
+  if (N != nullptr)
+    *N = S.getCurrentPosition();
+  return S.getBuffer();
+}
+
+char *ItaniumPartialDemangler::finishDemangle(char *Buf, size_t *N) const {
+  assert(RootNode != nullptr && "must call partialDemangle()");
+  return printNode(static_cast<Node *>(RootNode), Buf, N);
+}
+
+bool ItaniumPartialDemangler::hasFunctionQualifiers() const {
+  assert(RootNode != nullptr && "must call partialDemangle()");
+  if (!isFunction())
+    return false;
+  auto *E = static_cast<const FunctionEncoding *>(RootNode);
+  return E->getCVQuals() != QualNone || E->getRefQual() != FrefQualNone;
+}
+
+bool ItaniumPartialDemangler::isCtorOrDtor() const {
+  const Node *N = static_cast<const Node *>(RootNode);
+  while (N) {
+    switch (N->getKind()) {
+    default:
+      return false;
+    case Node::KCtorDtorName:
+      return true;
+
+    case Node::KAbiTagAttr:
+      N = static_cast<const AbiTagAttr *>(N)->Base;
+      break;
+    case Node::KFunctionEncoding:
+      N = static_cast<const FunctionEncoding *>(N)->getName();
+      break;
+    case Node::KLocalName:
+      N = static_cast<const LocalName *>(N)->Entity;
+      break;
+    case Node::KNameWithTemplateArgs:
+      N = static_cast<const NameWithTemplateArgs *>(N)->Name;
+      break;
+    case Node::KNestedName:
+      N = static_cast<const NestedName *>(N)->Name;
+      break;
+    case Node::KStdQualifiedName:
+      N = static_cast<const StdQualifiedName *>(N)->Child;
+      break;
+    }
+  }
+  return false;
+}
+
+bool ItaniumPartialDemangler::isFunction() const {
+  assert(RootNode != nullptr && "must call partialDemangle()");
+  return static_cast<const Node *>(RootNode)->getKind() ==
+         Node::KFunctionEncoding;
+}
+
+bool ItaniumPartialDemangler::isSpecialName() const {
+  assert(RootNode != nullptr && "must call partialDemangle()");
+  auto K = static_cast<const Node *>(RootNode)->getKind();
+  return K == Node::KSpecialName || K == Node::KCtorVtableSpecialName;
+}
+
+bool ItaniumPartialDemangler::isData() const {
+  return !isFunction() && !isSpecialName();
+}
diff --git a/externals/demangle/ItaniumDemangle.h b/externals/demangle/ItaniumDemangle.h
new file mode 100644
index 000000000..64b35c142
--- /dev/null
+++ b/externals/demangle/ItaniumDemangle.h
@@ -0,0 +1,5582 @@
+//===------------------------- ItaniumDemangle.h ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Generic itanium demangler library. This file has two byte-per-byte identical
+// copies in the source tree, one in libcxxabi, and the other in llvm.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef DEMANGLE_ITANIUMDEMANGLE_H
+#define DEMANGLE_ITANIUMDEMANGLE_H
+
+// FIXME: (possibly) incomplete list of features that clang mangles that this
+// file does not yet support:
+//   - C++ modules TS
+
+#include "DemangleConfig.h"
+#include "StringView.h"
+#include "Utility.h"
+#include <cassert>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <numeric>
+#include <utility>
+
+#define FOR_EACH_NODE_KIND(X) \
+    X(NodeArrayNode) \
+    X(DotSuffix) \
+    X(VendorExtQualType) \
+    X(QualType) \
+    X(ConversionOperatorType) \
+    X(PostfixQualifiedType) \
+    X(ElaboratedTypeSpefType) \
+    X(NameType) \
+    X(AbiTagAttr) \
+    X(EnableIfAttr) \
+    X(ObjCProtoName) \
+    X(PointerType) \
+    X(ReferenceType) \
+    X(PointerToMemberType) \
+    X(ArrayType) \
+    X(FunctionType) \
+    X(NoexceptSpec) \
+    X(DynamicExceptionSpec) \
+    X(FunctionEncoding) \
+    X(LiteralOperator) \
+    X(SpecialName) \
+    X(CtorVtableSpecialName) \
+    X(QualifiedName) \
+    X(NestedName) \
+    X(LocalName) \
+    X(VectorType) \
+    X(PixelVectorType) \
+    X(SyntheticTemplateParamName) \
+    X(TypeTemplateParamDecl) \
+    X(NonTypeTemplateParamDecl) \
+    X(TemplateTemplateParamDecl) \
+    X(TemplateParamPackDecl) \
+    X(ParameterPack) \
+    X(TemplateArgumentPack) \
+    X(ParameterPackExpansion) \
+    X(TemplateArgs) \
+    X(ForwardTemplateReference) \
+    X(NameWithTemplateArgs) \
+    X(GlobalQualifiedName) \
+    X(StdQualifiedName) \
+    X(ExpandedSpecialSubstitution) \
+    X(SpecialSubstitution) \
+    X(CtorDtorName) \
+    X(DtorName) \
+    X(UnnamedTypeName) \
+    X(ClosureTypeName) \
+    X(StructuredBindingName) \
+    X(BinaryExpr) \
+    X(ArraySubscriptExpr) \
+    X(PostfixExpr) \
+    X(ConditionalExpr) \
+    X(MemberExpr) \
+    X(EnclosingExpr) \
+    X(CastExpr) \
+    X(SizeofParamPackExpr) \
+    X(CallExpr) \
+    X(NewExpr) \
+    X(DeleteExpr) \
+    X(PrefixExpr) \
+    X(FunctionParam) \
+    X(ConversionExpr) \
+    X(InitListExpr) \
+    X(FoldExpr) \
+    X(ThrowExpr) \
+    X(UUIDOfExpr) \
+    X(BoolExpr) \
+    X(StringLiteral) \
+    X(LambdaExpr) \
+    X(IntegerCastExpr) \
+    X(IntegerLiteral) \
+    X(FloatLiteral) \
+    X(DoubleLiteral) \
+    X(LongDoubleLiteral) \
+    X(BracedExpr) \
+    X(BracedRangeExpr)
+
+DEMANGLE_NAMESPACE_BEGIN
+
+// Base class of all AST nodes. The AST is built by the parser, then is
+// traversed by the printLeft/Right functions to produce a demangled string.
+class Node {
+public:
+  enum Kind : unsigned char {
+#define ENUMERATOR(NodeKind) K ## NodeKind,
+    FOR_EACH_NODE_KIND(ENUMERATOR)
+#undef ENUMERATOR
+  };
+
+  /// Three-way bool to track a cached value. Unknown is possible if this node
+  /// has an unexpanded parameter pack below it that may affect this cache.
+  enum class Cache : unsigned char { Yes, No, Unknown, };
+
+private:
+  Kind K;
+
+  // FIXME: Make these protected.
+public:
+  /// Tracks if this node has a component on its right side, in which case we
+  /// need to call printRight.
+  Cache RHSComponentCache;
+
+  /// Track if this node is a (possibly qualified) array type. This can affect
+  /// how we format the output string.
+  Cache ArrayCache;
+
+  /// Track if this node is a (possibly qualified) function type. This can
+  /// affect how we format the output string.
+  Cache FunctionCache;
+
+public:
+  Node(Kind K_, Cache RHSComponentCache_ = Cache::No,
+       Cache ArrayCache_ = Cache::No, Cache FunctionCache_ = Cache::No)
+      : K(K_), RHSComponentCache(RHSComponentCache_), ArrayCache(ArrayCache_),
+        FunctionCache(FunctionCache_) {}
+
+  /// Visit the most-derived object corresponding to this object.
+  template<typename Fn> void visit(Fn F) const;
+
+  // The following function is provided by all derived classes:
+  //
+  // Call F with arguments that, when passed to the constructor of this node,
+  // would construct an equivalent node.
+  //template<typename Fn> void match(Fn F) const;
+
+  bool hasRHSComponent(OutputStream &S) const {
+    if (RHSComponentCache != Cache::Unknown)
+      return RHSComponentCache == Cache::Yes;
+    return hasRHSComponentSlow(S);
+  }
+
+  bool hasArray(OutputStream &S) const {
+    if (ArrayCache != Cache::Unknown)
+      return ArrayCache == Cache::Yes;
+    return hasArraySlow(S);
+  }
+
+  bool hasFunction(OutputStream &S) const {
+    if (FunctionCache != Cache::Unknown)
+      return FunctionCache == Cache::Yes;
+    return hasFunctionSlow(S);
+  }
+
+  Kind getKind() const { return K; }
+
+  virtual bool hasRHSComponentSlow(OutputStream &) const { return false; }
+  virtual bool hasArraySlow(OutputStream &) const { return false; }
+  virtual bool hasFunctionSlow(OutputStream &) const { return false; }
+
+  // Dig through "glue" nodes like ParameterPack and ForwardTemplateReference to
+  // get at a node that actually represents some concrete syntax.
+  virtual const Node *getSyntaxNode(OutputStream &) const {
+    return this;
+  }
+
+  void print(OutputStream &S) const {
+    printLeft(S);
+    if (RHSComponentCache != Cache::No)
+      printRight(S);
+  }
+
+  // Print the "left" side of this Node into OutputStream.
+  virtual void printLeft(OutputStream &) const = 0;
+
+  // Print the "right". This distinction is necessary to represent C++ types
+  // that appear on the RHS of their subtype, such as arrays or functions.
+  // Since most types don't have such a component, provide a default
+  // implementation.
+  virtual void printRight(OutputStream &) const {}
+
+  virtual StringView getBaseName() const { return StringView(); }
+
+  // Silence compiler warnings, this dtor will never be called.
+  virtual ~Node() = default;
+
+#ifndef NDEBUG
+  DEMANGLE_DUMP_METHOD void dump() const;
+#endif
+};
+
+class NodeArray {
+  Node **Elements;
+  size_t NumElements;
+
+public:
+  NodeArray() : Elements(nullptr), NumElements(0) {}
+  NodeArray(Node **Elements_, size_t NumElements_)
+      : Elements(Elements_), NumElements(NumElements_) {}
+
+  bool empty() const { return NumElements == 0; }
+  size_t size() const { return NumElements; }
+
+  Node **begin() const { return Elements; }
+  Node **end() const { return Elements + NumElements; }
+
+  Node *operator[](size_t Idx) const { return Elements[Idx]; }
+
+  void printWithComma(OutputStream &S) const {
+    bool FirstElement = true;
+    for (size_t Idx = 0; Idx != NumElements; ++Idx) {
+      size_t BeforeComma = S.getCurrentPosition();
+      if (!FirstElement)
+        S += ", ";
+      size_t AfterComma = S.getCurrentPosition();
+      Elements[Idx]->print(S);
+
+      // Elements[Idx] is an empty parameter pack expansion, we should erase the
+      // comma we just printed.
+      if (AfterComma == S.getCurrentPosition()) {
+        S.setCurrentPosition(BeforeComma);
+        continue;
+      }
+
+      FirstElement = false;
+    }
+  }
+};
+
+struct NodeArrayNode : Node {
+  NodeArray Array;
+  NodeArrayNode(NodeArray Array_) : Node(KNodeArrayNode), Array(Array_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Array); }
+
+  void printLeft(OutputStream &S) const override {
+    Array.printWithComma(S);
+  }
+};
+
+class DotSuffix final : public Node {
+  const Node *Prefix;
+  const StringView Suffix;
+
+public:
+  DotSuffix(const Node *Prefix_, StringView Suffix_)
+      : Node(KDotSuffix), Prefix(Prefix_), Suffix(Suffix_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Prefix, Suffix); }
+
+  void printLeft(OutputStream &s) const override {
+    Prefix->print(s);
+    s += " (";
+    s += Suffix;
+    s += ")";
+  }
+};
+
+class VendorExtQualType final : public Node {
+  const Node *Ty;
+  StringView Ext;
+
+public:
+  VendorExtQualType(const Node *Ty_, StringView Ext_)
+      : Node(KVendorExtQualType), Ty(Ty_), Ext(Ext_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty, Ext); }
+
+  void printLeft(OutputStream &S) const override {
+    Ty->print(S);
+    S += " ";
+    S += Ext;
+  }
+};
+
+enum FunctionRefQual : unsigned char {
+  FrefQualNone,
+  FrefQualLValue,
+  FrefQualRValue,
+};
+
+enum Qualifiers {
+  QualNone = 0,
+  QualConst = 0x1,
+  QualVolatile = 0x2,
+  QualRestrict = 0x4,
+};
+
+inline Qualifiers operator|=(Qualifiers &Q1, Qualifiers Q2) {
+  return Q1 = static_cast<Qualifiers>(Q1 | Q2);
+}
+
+class QualType final : public Node {
+protected:
+  const Qualifiers Quals;
+  const Node *Child;
+
+  void printQuals(OutputStream &S) const {
+    if (Quals & QualConst)
+      S += " const";
+    if (Quals & QualVolatile)
+      S += " volatile";
+    if (Quals & QualRestrict)
+      S += " restrict";
+  }
+
+public:
+  QualType(const Node *Child_, Qualifiers Quals_)
+      : Node(KQualType, Child_->RHSComponentCache,
+             Child_->ArrayCache, Child_->FunctionCache),
+        Quals(Quals_), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Child, Quals); }
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    return Child->hasRHSComponent(S);
+  }
+  bool hasArraySlow(OutputStream &S) const override {
+    return Child->hasArray(S);
+  }
+  bool hasFunctionSlow(OutputStream &S) const override {
+    return Child->hasFunction(S);
+  }
+
+  void printLeft(OutputStream &S) const override {
+    Child->printLeft(S);
+    printQuals(S);
+  }
+
+  void printRight(OutputStream &S) const override { Child->printRight(S); }
+};
+
+class ConversionOperatorType final : public Node {
+  const Node *Ty;
+
+public:
+  ConversionOperatorType(const Node *Ty_)
+      : Node(KConversionOperatorType), Ty(Ty_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "operator ";
+    Ty->print(S);
+  }
+};
+
+class PostfixQualifiedType final : public Node {
+  const Node *Ty;
+  const StringView Postfix;
+
+public:
+  PostfixQualifiedType(Node *Ty_, StringView Postfix_)
+      : Node(KPostfixQualifiedType), Ty(Ty_), Postfix(Postfix_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty, Postfix); }
+
+  void printLeft(OutputStream &s) const override {
+    Ty->printLeft(s);
+    s += Postfix;
+  }
+};
+
+class NameType final : public Node {
+  const StringView Name;
+
+public:
+  NameType(StringView Name_) : Node(KNameType), Name(Name_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Name); }
+
+  StringView getName() const { return Name; }
+  StringView getBaseName() const override { return Name; }
+
+  void printLeft(OutputStream &s) const override { s += Name; }
+};
+
+class ElaboratedTypeSpefType : public Node {
+  StringView Kind;
+  Node *Child;
+public:
+  ElaboratedTypeSpefType(StringView Kind_, Node *Child_)
+      : Node(KElaboratedTypeSpefType), Kind(Kind_), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Kind, Child); }
+
+  void printLeft(OutputStream &S) const override {
+    S += Kind;
+    S += ' ';
+    Child->print(S);
+  }
+};
+
+struct AbiTagAttr : Node {
+  Node *Base;
+  StringView Tag;
+
+  AbiTagAttr(Node* Base_, StringView Tag_)
+      : Node(KAbiTagAttr, Base_->RHSComponentCache,
+             Base_->ArrayCache, Base_->FunctionCache),
+        Base(Base_), Tag(Tag_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Base, Tag); }
+
+  void printLeft(OutputStream &S) const override {
+    Base->printLeft(S);
+    S += "[abi:";
+    S += Tag;
+    S += "]";
+  }
+};
+
+class EnableIfAttr : public Node {
+  NodeArray Conditions;
+public:
+  EnableIfAttr(NodeArray Conditions_)
+      : Node(KEnableIfAttr), Conditions(Conditions_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Conditions); }
+
+  void printLeft(OutputStream &S) const override {
+    S += " [enable_if:";
+    Conditions.printWithComma(S);
+    S += ']';
+  }
+};
+
+class ObjCProtoName : public Node {
+  const Node *Ty;
+  StringView Protocol;
+
+  friend class PointerType;
+
+public:
+  ObjCProtoName(const Node *Ty_, StringView Protocol_)
+      : Node(KObjCProtoName), Ty(Ty_), Protocol(Protocol_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty, Protocol); }
+
+  bool isObjCObject() const {
+    return Ty->getKind() == KNameType &&
+           static_cast<const NameType *>(Ty)->getName() == "objc_object";
+  }
+
+  void printLeft(OutputStream &S) const override {
+    Ty->print(S);
+    S += "<";
+    S += Protocol;
+    S += ">";
+  }
+};
+
+class PointerType final : public Node {
+  const Node *Pointee;
+
+public:
+  PointerType(const Node *Pointee_)
+      : Node(KPointerType, Pointee_->RHSComponentCache),
+        Pointee(Pointee_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Pointee); }
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    return Pointee->hasRHSComponent(S);
+  }
+
+  void printLeft(OutputStream &s) const override {
+    // We rewrite objc_object<SomeProtocol>* into id<SomeProtocol>.
+    if (Pointee->getKind() != KObjCProtoName ||
+        !static_cast<const ObjCProtoName *>(Pointee)->isObjCObject()) {
+      Pointee->printLeft(s);
+      if (Pointee->hasArray(s))
+        s += " ";
+      if (Pointee->hasArray(s) || Pointee->hasFunction(s))
+        s += "(";
+      s += "*";
+    } else {
+      const auto *objcProto = static_cast<const ObjCProtoName *>(Pointee);
+      s += "id<";
+      s += objcProto->Protocol;
+      s += ">";
+    }
+  }
+
+  void printRight(OutputStream &s) const override {
+    if (Pointee->getKind() != KObjCProtoName ||
+        !static_cast<const ObjCProtoName *>(Pointee)->isObjCObject()) {
+      if (Pointee->hasArray(s) || Pointee->hasFunction(s))
+        s += ")";
+      Pointee->printRight(s);
+    }
+  }
+};
+
+enum class ReferenceKind {
+  LValue,
+  RValue,
+};
+
+// Represents either a LValue or an RValue reference type.
+class ReferenceType : public Node {
+  const Node *Pointee;
+  ReferenceKind RK;
+
+  mutable bool Printing = false;
+
+  // Dig through any refs to refs, collapsing the ReferenceTypes as we go. The
+  // rule here is rvalue ref to rvalue ref collapses to a rvalue ref, and any
+  // other combination collapses to a lvalue ref.
+  std::pair<ReferenceKind, const Node *> collapse(OutputStream &S) const {
+    auto SoFar = std::make_pair(RK, Pointee);
+    for (;;) {
+      const Node *SN = SoFar.second->getSyntaxNode(S);
+      if (SN->getKind() != KReferenceType)
+        break;
+      auto *RT = static_cast<const ReferenceType *>(SN);
+      SoFar.second = RT->Pointee;
+      SoFar.first = std::min(SoFar.first, RT->RK);
+    }
+    return SoFar;
+  }
+
+public:
+  ReferenceType(const Node *Pointee_, ReferenceKind RK_)
+      : Node(KReferenceType, Pointee_->RHSComponentCache),
+        Pointee(Pointee_), RK(RK_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Pointee, RK); }
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    return Pointee->hasRHSComponent(S);
+  }
+
+  void printLeft(OutputStream &s) const override {
+    if (Printing)
+      return;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    std::pair<ReferenceKind, const Node *> Collapsed = collapse(s);
+    Collapsed.second->printLeft(s);
+    if (Collapsed.second->hasArray(s))
+      s += " ";
+    if (Collapsed.second->hasArray(s) || Collapsed.second->hasFunction(s))
+      s += "(";
+
+    s += (Collapsed.first == ReferenceKind::LValue ? "&" : "&&");
+  }
+  void printRight(OutputStream &s) const override {
+    if (Printing)
+      return;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    std::pair<ReferenceKind, const Node *> Collapsed = collapse(s);
+    if (Collapsed.second->hasArray(s) || Collapsed.second->hasFunction(s))
+      s += ")";
+    Collapsed.second->printRight(s);
+  }
+};
+
+class PointerToMemberType final : public Node {
+  const Node *ClassType;
+  const Node *MemberType;
+
+public:
+  PointerToMemberType(const Node *ClassType_, const Node *MemberType_)
+      : Node(KPointerToMemberType, MemberType_->RHSComponentCache),
+        ClassType(ClassType_), MemberType(MemberType_) {}
+
+  template<typename Fn> void match(Fn F) const { F(ClassType, MemberType); }
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    return MemberType->hasRHSComponent(S);
+  }
+
+  void printLeft(OutputStream &s) const override {
+    MemberType->printLeft(s);
+    if (MemberType->hasArray(s) || MemberType->hasFunction(s))
+      s += "(";
+    else
+      s += " ";
+    ClassType->print(s);
+    s += "::*";
+  }
+
+  void printRight(OutputStream &s) const override {
+    if (MemberType->hasArray(s) || MemberType->hasFunction(s))
+      s += ")";
+    MemberType->printRight(s);
+  }
+};
+
+class NodeOrString {
+  const void *First;
+  const void *Second;
+
+public:
+  /* implicit */ NodeOrString(StringView Str) {
+    const char *FirstChar = Str.begin();
+    const char *SecondChar = Str.end();
+    if (SecondChar == nullptr) {
+      assert(FirstChar == SecondChar);
+      ++FirstChar, ++SecondChar;
+    }
+    First = static_cast<const void *>(FirstChar);
+    Second = static_cast<const void *>(SecondChar);
+  }
+
+  /* implicit */ NodeOrString(Node *N)
+      : First(static_cast<const void *>(N)), Second(nullptr) {}
+  NodeOrString() : First(nullptr), Second(nullptr) {}
+
+  bool isString() const { return Second && First; }
+  bool isNode() const { return First && !Second; }
+  bool isEmpty() const { return !First && !Second; }
+
+  StringView asString() const {
+    assert(isString());
+    return StringView(static_cast<const char *>(First),
+                      static_cast<const char *>(Second));
+  }
+
+  const Node *asNode() const {
+    assert(isNode());
+    return static_cast<const Node *>(First);
+  }
+};
+
+class ArrayType final : public Node {
+  const Node *Base;
+  NodeOrString Dimension;
+
+public:
+  ArrayType(const Node *Base_, NodeOrString Dimension_)
+      : Node(KArrayType,
+             /*RHSComponentCache=*/Cache::Yes,
+             /*ArrayCache=*/Cache::Yes),
+        Base(Base_), Dimension(Dimension_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Base, Dimension); }
+
+  bool hasRHSComponentSlow(OutputStream &) const override { return true; }
+  bool hasArraySlow(OutputStream &) const override { return true; }
+
+  void printLeft(OutputStream &S) const override { Base->printLeft(S); }
+
+  void printRight(OutputStream &S) const override {
+    if (S.back() != ']')
+      S += " ";
+    S += "[";
+    if (Dimension.isString())
+      S += Dimension.asString();
+    else if (Dimension.isNode())
+      Dimension.asNode()->print(S);
+    S += "]";
+    Base->printRight(S);
+  }
+};
+
+class FunctionType final : public Node {
+  const Node *Ret;
+  NodeArray Params;
+  Qualifiers CVQuals;
+  FunctionRefQual RefQual;
+  const Node *ExceptionSpec;
+
+public:
+  FunctionType(const Node *Ret_, NodeArray Params_, Qualifiers CVQuals_,
+               FunctionRefQual RefQual_, const Node *ExceptionSpec_)
+      : Node(KFunctionType,
+             /*RHSComponentCache=*/Cache::Yes, /*ArrayCache=*/Cache::No,
+             /*FunctionCache=*/Cache::Yes),
+        Ret(Ret_), Params(Params_), CVQuals(CVQuals_), RefQual(RefQual_),
+        ExceptionSpec(ExceptionSpec_) {}
+
+  template<typename Fn> void match(Fn F) const {
+    F(Ret, Params, CVQuals, RefQual, ExceptionSpec);
+  }
+
+  bool hasRHSComponentSlow(OutputStream &) const override { return true; }
+  bool hasFunctionSlow(OutputStream &) const override { return true; }
+
+  // Handle C++'s ... quirky decl grammar by using the left & right
+  // distinction. Consider:
+  //   int (*f(float))(char) {}
+  // f is a function that takes a float and returns a pointer to a function
+  // that takes a char and returns an int. If we're trying to print f, start
+  // by printing out the return types's left, then print our parameters, then
+  // finally print right of the return type.
+  void printLeft(OutputStream &S) const override {
+    Ret->printLeft(S);
+    S += " ";
+  }
+
+  void printRight(OutputStream &S) const override {
+    S += "(";
+    Params.printWithComma(S);
+    S += ")";
+    Ret->printRight(S);
+
+    if (CVQuals & QualConst)
+      S += " const";
+    if (CVQuals & QualVolatile)
+      S += " volatile";
+    if (CVQuals & QualRestrict)
+      S += " restrict";
+
+    if (RefQual == FrefQualLValue)
+      S += " &";
+    else if (RefQual == FrefQualRValue)
+      S += " &&";
+
+    if (ExceptionSpec != nullptr) {
+      S += ' ';
+      ExceptionSpec->print(S);
+    }
+  }
+};
+
+class NoexceptSpec : public Node {
+  const Node *E;
+public:
+  NoexceptSpec(const Node *E_) : Node(KNoexceptSpec), E(E_) {}
+
+  template<typename Fn> void match(Fn F) const { F(E); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "noexcept(";
+    E->print(S);
+    S += ")";
+  }
+};
+
+class DynamicExceptionSpec : public Node {
+  NodeArray Types;
+public:
+  DynamicExceptionSpec(NodeArray Types_)
+      : Node(KDynamicExceptionSpec), Types(Types_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Types); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "throw(";
+    Types.printWithComma(S);
+    S += ')';
+  }
+};
+
+class FunctionEncoding final : public Node {
+  const Node *Ret;
+  const Node *Name;
+  NodeArray Params;
+  const Node *Attrs;
+  Qualifiers CVQuals;
+  FunctionRefQual RefQual;
+
+public:
+  FunctionEncoding(const Node *Ret_, const Node *Name_, NodeArray Params_,
+                   const Node *Attrs_, Qualifiers CVQuals_,
+                   FunctionRefQual RefQual_)
+      : Node(KFunctionEncoding,
+             /*RHSComponentCache=*/Cache::Yes, /*ArrayCache=*/Cache::No,
+             /*FunctionCache=*/Cache::Yes),
+        Ret(Ret_), Name(Name_), Params(Params_), Attrs(Attrs_),
+        CVQuals(CVQuals_), RefQual(RefQual_) {}
+
+  template<typename Fn> void match(Fn F) const {
+    F(Ret, Name, Params, Attrs, CVQuals, RefQual);
+  }
+
+  Qualifiers getCVQuals() const { return CVQuals; }
+  FunctionRefQual getRefQual() const { return RefQual; }
+  NodeArray getParams() const { return Params; }
+  const Node *getReturnType() const { return Ret; }
+
+  bool hasRHSComponentSlow(OutputStream &) const override { return true; }
+  bool hasFunctionSlow(OutputStream &) const override { return true; }
+
+  const Node *getName() const { return Name; }
+
+  void printLeft(OutputStream &S) const override {
+    if (Ret) {
+      Ret->printLeft(S);
+      if (!Ret->hasRHSComponent(S))
+        S += " ";
+    }
+    Name->print(S);
+  }
+
+  void printRight(OutputStream &S) const override {
+    S += "(";
+    Params.printWithComma(S);
+    S += ")";
+    if (Ret)
+      Ret->printRight(S);
+
+    if (CVQuals & QualConst)
+      S += " const";
+    if (CVQuals & QualVolatile)
+      S += " volatile";
+    if (CVQuals & QualRestrict)
+      S += " restrict";
+
+    if (RefQual == FrefQualLValue)
+      S += " &";
+    else if (RefQual == FrefQualRValue)
+      S += " &&";
+
+    if (Attrs != nullptr)
+      Attrs->print(S);
+  }
+};
+
+class LiteralOperator : public Node {
+  const Node *OpName;
+
+public:
+  LiteralOperator(const Node *OpName_)
+      : Node(KLiteralOperator), OpName(OpName_) {}
+
+  template<typename Fn> void match(Fn F) const { F(OpName); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "operator\"\" ";
+    OpName->print(S);
+  }
+};
+
+class SpecialName final : public Node {
+  const StringView Special;
+  const Node *Child;
+
+public:
+  SpecialName(StringView Special_, const Node *Child_)
+      : Node(KSpecialName), Special(Special_), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Special, Child); }
+
+  void printLeft(OutputStream &S) const override {
+    S += Special;
+    Child->print(S);
+  }
+};
+
+class CtorVtableSpecialName final : public Node {
+  const Node *FirstType;
+  const Node *SecondType;
+
+public:
+  CtorVtableSpecialName(const Node *FirstType_, const Node *SecondType_)
+      : Node(KCtorVtableSpecialName),
+        FirstType(FirstType_), SecondType(SecondType_) {}
+
+  template<typename Fn> void match(Fn F) const { F(FirstType, SecondType); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "construction vtable for ";
+    FirstType->print(S);
+    S += "-in-";
+    SecondType->print(S);
+  }
+};
+
+struct NestedName : Node {
+  Node *Qual;
+  Node *Name;
+
+  NestedName(Node *Qual_, Node *Name_)
+      : Node(KNestedName), Qual(Qual_), Name(Name_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Qual, Name); }
+
+  StringView getBaseName() const override { return Name->getBaseName(); }
+
+  void printLeft(OutputStream &S) const override {
+    Qual->print(S);
+    S += "::";
+    Name->print(S);
+  }
+};
+
+struct LocalName : Node {
+  Node *Encoding;
+  Node *Entity;
+
+  LocalName(Node *Encoding_, Node *Entity_)
+      : Node(KLocalName), Encoding(Encoding_), Entity(Entity_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Encoding, Entity); }
+
+  void printLeft(OutputStream &S) const override {
+    Encoding->print(S);
+    S += "::";
+    Entity->print(S);
+  }
+};
+
+class QualifiedName final : public Node {
+  // qualifier::name
+  const Node *Qualifier;
+  const Node *Name;
+
+public:
+  QualifiedName(const Node *Qualifier_, const Node *Name_)
+      : Node(KQualifiedName), Qualifier(Qualifier_), Name(Name_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Qualifier, Name); }
+
+  StringView getBaseName() const override { return Name->getBaseName(); }
+
+  void printLeft(OutputStream &S) const override {
+    Qualifier->print(S);
+    S += "::";
+    Name->print(S);
+  }
+};
+
+class VectorType final : public Node {
+  const Node *BaseType;
+  const NodeOrString Dimension;
+
+public:
+  VectorType(const Node *BaseType_, NodeOrString Dimension_)
+      : Node(KVectorType), BaseType(BaseType_),
+        Dimension(Dimension_) {}
+
+  template<typename Fn> void match(Fn F) const { F(BaseType, Dimension); }
+
+  void printLeft(OutputStream &S) const override {
+    BaseType->print(S);
+    S += " vector[";
+    if (Dimension.isNode())
+      Dimension.asNode()->print(S);
+    else if (Dimension.isString())
+      S += Dimension.asString();
+    S += "]";
+  }
+};
+
+class PixelVectorType final : public Node {
+  const NodeOrString Dimension;
+
+public:
+  PixelVectorType(NodeOrString Dimension_)
+      : Node(KPixelVectorType), Dimension(Dimension_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Dimension); }
+
+  void printLeft(OutputStream &S) const override {
+    // FIXME: This should demangle as "vector pixel".
+    S += "pixel vector[";
+    S += Dimension.asString();
+    S += "]";
+  }
+};
+
+enum class TemplateParamKind { Type, NonType, Template };
+
+/// An invented name for a template parameter for which we don't have a
+/// corresponding template argument.
+///
+/// This node is created when parsing the <lambda-sig> for a lambda with
+/// explicit template arguments, which might be referenced in the parameter
+/// types appearing later in the <lambda-sig>.
+class SyntheticTemplateParamName final : public Node {
+  TemplateParamKind Kind;
+  unsigned Index;
+
+public:
+  SyntheticTemplateParamName(TemplateParamKind Kind_, unsigned Index_)
+      : Node(KSyntheticTemplateParamName), Kind(Kind_), Index(Index_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Kind, Index); }
+
+  void printLeft(OutputStream &S) const override {
+    switch (Kind) {
+    case TemplateParamKind::Type:
+      S += "$T";
+      break;
+    case TemplateParamKind::NonType:
+      S += "$N";
+      break;
+    case TemplateParamKind::Template:
+      S += "$TT";
+      break;
+    }
+    if (Index > 0)
+      S << Index - 1;
+  }
+};
+
+/// A template type parameter declaration, 'typename T'.
+class TypeTemplateParamDecl final : public Node {
+  Node *Name;
+
+public:
+  TypeTemplateParamDecl(Node *Name_)
+      : Node(KTypeTemplateParamDecl, Cache::Yes), Name(Name_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Name); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "typename ";
+  }
+
+  void printRight(OutputStream &S) const override {
+    Name->print(S);
+  }
+};
+
+/// A non-type template parameter declaration, 'int N'.
+class NonTypeTemplateParamDecl final : public Node {
+  Node *Name;
+  Node *Type;
+
+public:
+  NonTypeTemplateParamDecl(Node *Name_, Node *Type_)
+      : Node(KNonTypeTemplateParamDecl, Cache::Yes), Name(Name_), Type(Type_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Name, Type); }
+
+  void printLeft(OutputStream &S) const override {
+    Type->printLeft(S);
+    if (!Type->hasRHSComponent(S))
+      S += " ";
+  }
+
+  void printRight(OutputStream &S) const override {
+    Name->print(S);
+    Type->printRight(S);
+  }
+};
+
+/// A template template parameter declaration,
+/// 'template<typename T> typename N'.
+class TemplateTemplateParamDecl final : public Node {
+  Node *Name;
+  NodeArray Params;
+
+public:
+  TemplateTemplateParamDecl(Node *Name_, NodeArray Params_)
+      : Node(KTemplateTemplateParamDecl, Cache::Yes), Name(Name_),
+        Params(Params_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Name, Params); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "template<";
+    Params.printWithComma(S);
+    S += "> typename ";
+  }
+
+  void printRight(OutputStream &S) const override {
+    Name->print(S);
+  }
+};
+
+/// A template parameter pack declaration, 'typename ...T'.
+class TemplateParamPackDecl final : public Node {
+  Node *Param;
+
+public:
+  TemplateParamPackDecl(Node *Param_)
+      : Node(KTemplateParamPackDecl, Cache::Yes), Param(Param_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Param); }
+
+  void printLeft(OutputStream &S) const override {
+    Param->printLeft(S);
+    S += "...";
+  }
+
+  void printRight(OutputStream &S) const override {
+    Param->printRight(S);
+  }
+};
+
+/// An unexpanded parameter pack (either in the expression or type context). If
+/// this AST is correct, this node will have a ParameterPackExpansion node above
+/// it.
+///
+/// This node is created when some <template-args> are found that apply to an
+/// <encoding>, and is stored in the TemplateParams table. In order for this to
+/// appear in the final AST, it has to referenced via a <template-param> (ie,
+/// T_).
+class ParameterPack final : public Node {
+  NodeArray Data;
+
+  // Setup OutputStream for a pack expansion unless we're already expanding one.
+  void initializePackExpansion(OutputStream &S) const {
+    if (S.CurrentPackMax == std::numeric_limits<unsigned>::max()) {
+      S.CurrentPackMax = static_cast<unsigned>(Data.size());
+      S.CurrentPackIndex = 0;
+    }
+  }
+
+public:
+  ParameterPack(NodeArray Data_) : Node(KParameterPack), Data(Data_) {
+    ArrayCache = FunctionCache = RHSComponentCache = Cache::Unknown;
+    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
+          return P->ArrayCache == Cache::No;
+        }))
+      ArrayCache = Cache::No;
+    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
+          return P->FunctionCache == Cache::No;
+        }))
+      FunctionCache = Cache::No;
+    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
+          return P->RHSComponentCache == Cache::No;
+        }))
+      RHSComponentCache = Cache::No;
+  }
+
+  template<typename Fn> void match(Fn F) const { F(Data); }
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    return Idx < Data.size() && Data[Idx]->hasRHSComponent(S);
+  }
+  bool hasArraySlow(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    return Idx < Data.size() && Data[Idx]->hasArray(S);
+  }
+  bool hasFunctionSlow(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    return Idx < Data.size() && Data[Idx]->hasFunction(S);
+  }
+  const Node *getSyntaxNode(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    return Idx < Data.size() ? Data[Idx]->getSyntaxNode(S) : this;
+  }
+
+  void printLeft(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    if (Idx < Data.size())
+      Data[Idx]->printLeft(S);
+  }
+  void printRight(OutputStream &S) const override {
+    initializePackExpansion(S);
+    size_t Idx = S.CurrentPackIndex;
+    if (Idx < Data.size())
+      Data[Idx]->printRight(S);
+  }
+};
+
+/// A variadic template argument. This node represents an occurrence of
+/// J<something>E in some <template-args>. It isn't itself unexpanded, unless
+/// one of it's Elements is. The parser inserts a ParameterPack into the
+/// TemplateParams table if the <template-args> this pack belongs to apply to an
+/// <encoding>.
+class TemplateArgumentPack final : public Node {
+  NodeArray Elements;
+public:
+  TemplateArgumentPack(NodeArray Elements_)
+      : Node(KTemplateArgumentPack), Elements(Elements_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Elements); }
+
+  NodeArray getElements() const { return Elements; }
+
+  void printLeft(OutputStream &S) const override {
+    Elements.printWithComma(S);
+  }
+};
+
+/// A pack expansion. Below this node, there are some unexpanded ParameterPacks
+/// which each have Child->ParameterPackSize elements.
+class ParameterPackExpansion final : public Node {
+  const Node *Child;
+
+public:
+  ParameterPackExpansion(const Node *Child_)
+      : Node(KParameterPackExpansion), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Child); }
+
+  const Node *getChild() const { return Child; }
+
+  void printLeft(OutputStream &S) const override {
+    constexpr unsigned Max = std::numeric_limits<unsigned>::max();
+    SwapAndRestore<unsigned> SavePackIdx(S.CurrentPackIndex, Max);
+    SwapAndRestore<unsigned> SavePackMax(S.CurrentPackMax, Max);
+    size_t StreamPos = S.getCurrentPosition();
+
+    // Print the first element in the pack. If Child contains a ParameterPack,
+    // it will set up S.CurrentPackMax and print the first element.
+    Child->print(S);
+
+    // No ParameterPack was found in Child. This can occur if we've found a pack
+    // expansion on a <function-param>.
+    if (S.CurrentPackMax == Max) {
+      S += "...";
+      return;
+    }
+
+    // We found a ParameterPack, but it has no elements. Erase whatever we may
+    // of printed.
+    if (S.CurrentPackMax == 0) {
+      S.setCurrentPosition(StreamPos);
+      return;
+    }
+
+    // Else, iterate through the rest of the elements in the pack.
+    for (unsigned I = 1, E = S.CurrentPackMax; I < E; ++I) {
+      S += ", ";
+      S.CurrentPackIndex = I;
+      Child->print(S);
+    }
+  }
+};
+
+class TemplateArgs final : public Node {
+  NodeArray Params;
+
+public:
+  TemplateArgs(NodeArray Params_) : Node(KTemplateArgs), Params(Params_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Params); }
+
+  NodeArray getParams() { return Params; }
+
+  void printLeft(OutputStream &S) const override {
+    S += "<";
+    Params.printWithComma(S);
+    if (S.back() == '>')
+      S += " ";
+    S += ">";
+  }
+};
+
+/// A forward-reference to a template argument that was not known at the point
+/// where the template parameter name was parsed in a mangling.
+///
+/// This is created when demangling the name of a specialization of a
+/// conversion function template:
+///
+/// \code
+/// struct A {
+///   template<typename T> operator T*();
+/// };
+/// \endcode
+///
+/// When demangling a specialization of the conversion function template, we
+/// encounter the name of the template (including the \c T) before we reach
+/// the template argument list, so we cannot substitute the parameter name
+/// for the corresponding argument while parsing. Instead, we create a
+/// \c ForwardTemplateReference node that is resolved after we parse the
+/// template arguments.
+struct ForwardTemplateReference : Node {
+  size_t Index;
+  Node *Ref = nullptr;
+
+  // If we're currently printing this node. It is possible (though invalid) for
+  // a forward template reference to refer to itself via a substitution. This
+  // creates a cyclic AST, which will stack overflow printing. To fix this, bail
+  // out if more than one print* function is active.
+  mutable bool Printing = false;
+
+  ForwardTemplateReference(size_t Index_)
+      : Node(KForwardTemplateReference, Cache::Unknown, Cache::Unknown,
+             Cache::Unknown),
+        Index(Index_) {}
+
+  // We don't provide a matcher for these, because the value of the node is
+  // not determined by its construction parameters, and it generally needs
+  // special handling.
+  template<typename Fn> void match(Fn F) const = delete;
+
+  bool hasRHSComponentSlow(OutputStream &S) const override {
+    if (Printing)
+      return false;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    return Ref->hasRHSComponent(S);
+  }
+  bool hasArraySlow(OutputStream &S) const override {
+    if (Printing)
+      return false;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    return Ref->hasArray(S);
+  }
+  bool hasFunctionSlow(OutputStream &S) const override {
+    if (Printing)
+      return false;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    return Ref->hasFunction(S);
+  }
+  const Node *getSyntaxNode(OutputStream &S) const override {
+    if (Printing)
+      return this;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    return Ref->getSyntaxNode(S);
+  }
+
+  void printLeft(OutputStream &S) const override {
+    if (Printing)
+      return;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    Ref->printLeft(S);
+  }
+  void printRight(OutputStream &S) const override {
+    if (Printing)
+      return;
+    SwapAndRestore<bool> SavePrinting(Printing, true);
+    Ref->printRight(S);
+  }
+};
+
+struct NameWithTemplateArgs : Node {
+  // name<template_args>
+  Node *Name;
+  Node *TemplateArgs;
+
+  NameWithTemplateArgs(Node *Name_, Node *TemplateArgs_)
+      : Node(KNameWithTemplateArgs), Name(Name_), TemplateArgs(TemplateArgs_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Name, TemplateArgs); }
+
+  StringView getBaseName() const override { return Name->getBaseName(); }
+
+  void printLeft(OutputStream &S) const override {
+    Name->print(S);
+    TemplateArgs->print(S);
+  }
+};
+
+class GlobalQualifiedName final : public Node {
+  Node *Child;
+
+public:
+  GlobalQualifiedName(Node* Child_)
+      : Node(KGlobalQualifiedName), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Child); }
+
+  StringView getBaseName() const override { return Child->getBaseName(); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "::";
+    Child->print(S);
+  }
+};
+
+struct StdQualifiedName : Node {
+  Node *Child;
+
+  StdQualifiedName(Node *Child_) : Node(KStdQualifiedName), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Child); }
+
+  StringView getBaseName() const override { return Child->getBaseName(); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "std::";
+    Child->print(S);
+  }
+};
+
+enum class SpecialSubKind {
+  allocator,
+  basic_string,
+  string,
+  istream,
+  ostream,
+  iostream,
+};
+
+class ExpandedSpecialSubstitution final : public Node {
+  SpecialSubKind SSK;
+
+public:
+  ExpandedSpecialSubstitution(SpecialSubKind SSK_)
+      : Node(KExpandedSpecialSubstitution), SSK(SSK_) {}
+
+  template<typename Fn> void match(Fn F) const { F(SSK); }
+
+  StringView getBaseName() const override {
+    switch (SSK) {
+    case SpecialSubKind::allocator:
+      return StringView("allocator");
+    case SpecialSubKind::basic_string:
+      return StringView("basic_string");
+    case SpecialSubKind::string:
+      return StringView("basic_string");
+    case SpecialSubKind::istream:
+      return StringView("basic_istream");
+    case SpecialSubKind::ostream:
+      return StringView("basic_ostream");
+    case SpecialSubKind::iostream:
+      return StringView("basic_iostream");
+    }
+    DEMANGLE_UNREACHABLE;
+  }
+
+  void printLeft(OutputStream &S) const override {
+    switch (SSK) {
+    case SpecialSubKind::allocator:
+      S += "std::allocator";
+      break;
+    case SpecialSubKind::basic_string:
+      S += "std::basic_string";
+      break;
+    case SpecialSubKind::string:
+      S += "std::basic_string<char, std::char_traits<char>, "
+           "std::allocator<char> >";
+      break;
+    case SpecialSubKind::istream:
+      S += "std::basic_istream<char, std::char_traits<char> >";
+      break;
+    case SpecialSubKind::ostream:
+      S += "std::basic_ostream<char, std::char_traits<char> >";
+      break;
+    case SpecialSubKind::iostream:
+      S += "std::basic_iostream<char, std::char_traits<char> >";
+      break;
+    }
+  }
+};
+
+class SpecialSubstitution final : public Node {
+public:
+  SpecialSubKind SSK;
+
+  SpecialSubstitution(SpecialSubKind SSK_)
+      : Node(KSpecialSubstitution), SSK(SSK_) {}
+
+  template<typename Fn> void match(Fn F) const { F(SSK); }
+
+  StringView getBaseName() const override {
+    switch (SSK) {
+    case SpecialSubKind::allocator:
+      return StringView("allocator");
+    case SpecialSubKind::basic_string:
+      return StringView("basic_string");
+    case SpecialSubKind::string:
+      return StringView("string");
+    case SpecialSubKind::istream:
+      return StringView("istream");
+    case SpecialSubKind::ostream:
+      return StringView("ostream");
+    case SpecialSubKind::iostream:
+      return StringView("iostream");
+    }
+    DEMANGLE_UNREACHABLE;
+  }
+
+  void printLeft(OutputStream &S) const override {
+    switch (SSK) {
+    case SpecialSubKind::allocator:
+      S += "std::allocator";
+      break;
+    case SpecialSubKind::basic_string:
+      S += "std::basic_string";
+      break;
+    case SpecialSubKind::string:
+      S += "std::string";
+      break;
+    case SpecialSubKind::istream:
+      S += "std::istream";
+      break;
+    case SpecialSubKind::ostream:
+      S += "std::ostream";
+      break;
+    case SpecialSubKind::iostream:
+      S += "std::iostream";
+      break;
+    }
+  }
+};
+
+class CtorDtorName final : public Node {
+  const Node *Basename;
+  const bool IsDtor;
+  const int Variant;
+
+public:
+  CtorDtorName(const Node *Basename_, bool IsDtor_, int Variant_)
+      : Node(KCtorDtorName), Basename(Basename_), IsDtor(IsDtor_),
+        Variant(Variant_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Basename, IsDtor, Variant); }
+
+  void printLeft(OutputStream &S) const override {
+    if (IsDtor)
+      S += "~";
+    S += Basename->getBaseName();
+  }
+};
+
+class DtorName : public Node {
+  const Node *Base;
+
+public:
+  DtorName(const Node *Base_) : Node(KDtorName), Base(Base_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Base); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "~";
+    Base->printLeft(S);
+  }
+};
+
+class UnnamedTypeName : public Node {
+  const StringView Count;
+
+public:
+  UnnamedTypeName(StringView Count_) : Node(KUnnamedTypeName), Count(Count_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Count); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "'unnamed";
+    S += Count;
+    S += "\'";
+  }
+};
+
+class ClosureTypeName : public Node {
+  NodeArray TemplateParams;
+  NodeArray Params;
+  StringView Count;
+
+public:
+  ClosureTypeName(NodeArray TemplateParams_, NodeArray Params_,
+                  StringView Count_)
+      : Node(KClosureTypeName), TemplateParams(TemplateParams_),
+        Params(Params_), Count(Count_) {}
+
+  template<typename Fn> void match(Fn F) const {
+    F(TemplateParams, Params, Count);
+  }
+
+  void printDeclarator(OutputStream &S) const {
+    if (!TemplateParams.empty()) {
+      S += "<";
+      TemplateParams.printWithComma(S);
+      S += ">";
+    }
+    S += "(";
+    Params.printWithComma(S);
+    S += ")";
+  }
+
+  void printLeft(OutputStream &S) const override {
+    S += "\'lambda";
+    S += Count;
+    S += "\'";
+    printDeclarator(S);
+  }
+};
+
+class StructuredBindingName : public Node {
+  NodeArray Bindings;
+public:
+  StructuredBindingName(NodeArray Bindings_)
+      : Node(KStructuredBindingName), Bindings(Bindings_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Bindings); }
+
+  void printLeft(OutputStream &S) const override {
+    S += '[';
+    Bindings.printWithComma(S);
+    S += ']';
+  }
+};
+
+// -- Expression Nodes --
+
+class BinaryExpr : public Node {
+  const Node *LHS;
+  const StringView InfixOperator;
+  const Node *RHS;
+
+public:
+  BinaryExpr(const Node *LHS_, StringView InfixOperator_, const Node *RHS_)
+      : Node(KBinaryExpr), LHS(LHS_), InfixOperator(InfixOperator_), RHS(RHS_) {
+  }
+
+  template<typename Fn> void match(Fn F) const { F(LHS, InfixOperator, RHS); }
+
+  void printLeft(OutputStream &S) const override {
+    // might be a template argument expression, then we need to disambiguate
+    // with parens.
+    if (InfixOperator == ">")
+      S += "(";
+
+    S += "(";
+    LHS->print(S);
+    S += ") ";
+    S += InfixOperator;
+    S += " (";
+    RHS->print(S);
+    S += ")";
+
+    if (InfixOperator == ">")
+      S += ")";
+  }
+};
+
+class ArraySubscriptExpr : public Node {
+  const Node *Op1;
+  const Node *Op2;
+
+public:
+  ArraySubscriptExpr(const Node *Op1_, const Node *Op2_)
+      : Node(KArraySubscriptExpr), Op1(Op1_), Op2(Op2_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Op1, Op2); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "(";
+    Op1->print(S);
+    S += ")[";
+    Op2->print(S);
+    S += "]";
+  }
+};
+
+class PostfixExpr : public Node {
+  const Node *Child;
+  const StringView Operator;
+
+public:
+  PostfixExpr(const Node *Child_, StringView Operator_)
+      : Node(KPostfixExpr), Child(Child_), Operator(Operator_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Child, Operator); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "(";
+    Child->print(S);
+    S += ")";
+    S += Operator;
+  }
+};
+
+class ConditionalExpr : public Node {
+  const Node *Cond;
+  const Node *Then;
+  const Node *Else;
+
+public:
+  ConditionalExpr(const Node *Cond_, const Node *Then_, const Node *Else_)
+      : Node(KConditionalExpr), Cond(Cond_), Then(Then_), Else(Else_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Cond, Then, Else); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "(";
+    Cond->print(S);
+    S += ") ? (";
+    Then->print(S);
+    S += ") : (";
+    Else->print(S);
+    S += ")";
+  }
+};
+
+class MemberExpr : public Node {
+  const Node *LHS;
+  const StringView Kind;
+  const Node *RHS;
+
+public:
+  MemberExpr(const Node *LHS_, StringView Kind_, const Node *RHS_)
+      : Node(KMemberExpr), LHS(LHS_), Kind(Kind_), RHS(RHS_) {}
+
+  template<typename Fn> void match(Fn F) const { F(LHS, Kind, RHS); }
+
+  void printLeft(OutputStream &S) const override {
+    LHS->print(S);
+    S += Kind;
+    RHS->print(S);
+  }
+};
+
+class EnclosingExpr : public Node {
+  const StringView Prefix;
+  const Node *Infix;
+  const StringView Postfix;
+
+public:
+  EnclosingExpr(StringView Prefix_, Node *Infix_, StringView Postfix_)
+      : Node(KEnclosingExpr), Prefix(Prefix_), Infix(Infix_),
+        Postfix(Postfix_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Prefix, Infix, Postfix); }
+
+  void printLeft(OutputStream &S) const override {
+    S += Prefix;
+    Infix->print(S);
+    S += Postfix;
+  }
+};
+
+class CastExpr : public Node {
+  // cast_kind<to>(from)
+  const StringView CastKind;
+  const Node *To;
+  const Node *From;
+
+public:
+  CastExpr(StringView CastKind_, const Node *To_, const Node *From_)
+      : Node(KCastExpr), CastKind(CastKind_), To(To_), From(From_) {}
+
+  template<typename Fn> void match(Fn F) const { F(CastKind, To, From); }
+
+  void printLeft(OutputStream &S) const override {
+    S += CastKind;
+    S += "<";
+    To->printLeft(S);
+    S += ">(";
+    From->printLeft(S);
+    S += ")";
+  }
+};
+
+class SizeofParamPackExpr : public Node {
+  const Node *Pack;
+
+public:
+  SizeofParamPackExpr(const Node *Pack_)
+      : Node(KSizeofParamPackExpr), Pack(Pack_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Pack); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "sizeof...(";
+    ParameterPackExpansion PPE(Pack);
+    PPE.printLeft(S);
+    S += ")";
+  }
+};
+
+class CallExpr : public Node {
+  const Node *Callee;
+  NodeArray Args;
+
+public:
+  CallExpr(const Node *Callee_, NodeArray Args_)
+      : Node(KCallExpr), Callee(Callee_), Args(Args_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Callee, Args); }
+
+  void printLeft(OutputStream &S) const override {
+    Callee->print(S);
+    S += "(";
+    Args.printWithComma(S);
+    S += ")";
+  }
+};
+
+class NewExpr : public Node {
+  // new (expr_list) type(init_list)
+  NodeArray ExprList;
+  Node *Type;
+  NodeArray InitList;
+  bool IsGlobal; // ::operator new ?
+  bool IsArray;  // new[] ?
+public:
+  NewExpr(NodeArray ExprList_, Node *Type_, NodeArray InitList_, bool IsGlobal_,
+          bool IsArray_)
+      : Node(KNewExpr), ExprList(ExprList_), Type(Type_), InitList(InitList_),
+        IsGlobal(IsGlobal_), IsArray(IsArray_) {}
+
+  template<typename Fn> void match(Fn F) const {
+    F(ExprList, Type, InitList, IsGlobal, IsArray);
+  }
+
+  void printLeft(OutputStream &S) const override {
+    if (IsGlobal)
+      S += "::operator ";
+    S += "new";
+    if (IsArray)
+      S += "[]";
+    S += ' ';
+    if (!ExprList.empty()) {
+      S += "(";
+      ExprList.printWithComma(S);
+      S += ")";
+    }
+    Type->print(S);
+    if (!InitList.empty()) {
+      S += "(";
+      InitList.printWithComma(S);
+      S += ")";
+    }
+
+  }
+};
+
+class DeleteExpr : public Node {
+  Node *Op;
+  bool IsGlobal;
+  bool IsArray;
+
+public:
+  DeleteExpr(Node *Op_, bool IsGlobal_, bool IsArray_)
+      : Node(KDeleteExpr), Op(Op_), IsGlobal(IsGlobal_), IsArray(IsArray_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Op, IsGlobal, IsArray); }
+
+  void printLeft(OutputStream &S) const override {
+    if (IsGlobal)
+      S += "::";
+    S += "delete";
+    if (IsArray)
+      S += "[] ";
+    Op->print(S);
+  }
+};
+
+class PrefixExpr : public Node {
+  StringView Prefix;
+  Node *Child;
+
+public:
+  PrefixExpr(StringView Prefix_, Node *Child_)
+      : Node(KPrefixExpr), Prefix(Prefix_), Child(Child_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Prefix, Child); }
+
+  void printLeft(OutputStream &S) const override {
+    S += Prefix;
+    S += "(";
+    Child->print(S);
+    S += ")";
+  }
+};
+
+class FunctionParam : public Node {
+  StringView Number;
+
+public:
+  FunctionParam(StringView Number_) : Node(KFunctionParam), Number(Number_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Number); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "fp";
+    S += Number;
+  }
+};
+
+class ConversionExpr : public Node {
+  const Node *Type;
+  NodeArray Expressions;
+
+public:
+  ConversionExpr(const Node *Type_, NodeArray Expressions_)
+      : Node(KConversionExpr), Type(Type_), Expressions(Expressions_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Type, Expressions); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "(";
+    Type->print(S);
+    S += ")(";
+    Expressions.printWithComma(S);
+    S += ")";
+  }
+};
+
+class InitListExpr : public Node {
+  const Node *Ty;
+  NodeArray Inits;
+public:
+  InitListExpr(const Node *Ty_, NodeArray Inits_)
+      : Node(KInitListExpr), Ty(Ty_), Inits(Inits_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty, Inits); }
+
+  void printLeft(OutputStream &S) const override {
+    if (Ty)
+      Ty->print(S);
+    S += '{';
+    Inits.printWithComma(S);
+    S += '}';
+  }
+};
+
+class BracedExpr : public Node {
+  const Node *Elem;
+  const Node *Init;
+  bool IsArray;
+public:
+  BracedExpr(const Node *Elem_, const Node *Init_, bool IsArray_)
+      : Node(KBracedExpr), Elem(Elem_), Init(Init_), IsArray(IsArray_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Elem, Init, IsArray); }
+
+  void printLeft(OutputStream &S) const override {
+    if (IsArray) {
+      S += '[';
+      Elem->print(S);
+      S += ']';
+    } else {
+      S += '.';
+      Elem->print(S);
+    }
+    if (Init->getKind() != KBracedExpr && Init->getKind() != KBracedRangeExpr)
+      S += " = ";
+    Init->print(S);
+  }
+};
+
+class BracedRangeExpr : public Node {
+  const Node *First;
+  const Node *Last;
+  const Node *Init;
+public:
+  BracedRangeExpr(const Node *First_, const Node *Last_, const Node *Init_)
+      : Node(KBracedRangeExpr), First(First_), Last(Last_), Init(Init_) {}
+
+  template<typename Fn> void match(Fn F) const { F(First, Last, Init); }
+
+  void printLeft(OutputStream &S) const override {
+    S += '[';
+    First->print(S);
+    S += " ... ";
+    Last->print(S);
+    S += ']';
+    if (Init->getKind() != KBracedExpr && Init->getKind() != KBracedRangeExpr)
+      S += " = ";
+    Init->print(S);
+  }
+};
+
+class FoldExpr : public Node {
+  const Node *Pack, *Init;
+  StringView OperatorName;
+  bool IsLeftFold;
+
+public:
+  FoldExpr(bool IsLeftFold_, StringView OperatorName_, const Node *Pack_,
+           const Node *Init_)
+      : Node(KFoldExpr), Pack(Pack_), Init(Init_), OperatorName(OperatorName_),
+        IsLeftFold(IsLeftFold_) {}
+
+  template<typename Fn> void match(Fn F) const {
+    F(IsLeftFold, OperatorName, Pack, Init);
+  }
+
+  void printLeft(OutputStream &S) const override {
+    auto PrintPack = [&] {
+      S += '(';
+      ParameterPackExpansion(Pack).print(S);
+      S += ')';
+    };
+
+    S += '(';
+
+    if (IsLeftFold) {
+      // init op ... op pack
+      if (Init != nullptr) {
+        Init->print(S);
+        S += ' ';
+        S += OperatorName;
+        S += ' ';
+      }
+      // ... op pack
+      S += "... ";
+      S += OperatorName;
+      S += ' ';
+      PrintPack();
+    } else { // !IsLeftFold
+      // pack op ...
+      PrintPack();
+      S += ' ';
+      S += OperatorName;
+      S += " ...";
+      // pack op ... op init
+      if (Init != nullptr) {
+        S += ' ';
+        S += OperatorName;
+        S += ' ';
+        Init->print(S);
+      }
+    }
+    S += ')';
+  }
+};
+
+class ThrowExpr : public Node {
+  const Node *Op;
+
+public:
+  ThrowExpr(const Node *Op_) : Node(KThrowExpr), Op(Op_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Op); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "throw ";
+    Op->print(S);
+  }
+};
+
+// MSVC __uuidof extension, generated by clang in -fms-extensions mode.
+class UUIDOfExpr : public Node {
+  Node *Operand;
+public:
+  UUIDOfExpr(Node *Operand_) : Node(KUUIDOfExpr), Operand(Operand_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Operand); }
+
+  void printLeft(OutputStream &S) const override {
+    S << "__uuidof(";
+    Operand->print(S);
+    S << ")";
+  }
+};
+
+class BoolExpr : public Node {
+  bool Value;
+
+public:
+  BoolExpr(bool Value_) : Node(KBoolExpr), Value(Value_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Value); }
+
+  void printLeft(OutputStream &S) const override {
+    S += Value ? StringView("true") : StringView("false");
+  }
+};
+
+class StringLiteral : public Node {
+  const Node *Type;
+
+public:
+  StringLiteral(const Node *Type_) : Node(KStringLiteral), Type(Type_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Type); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "\"<";
+    Type->print(S);
+    S += ">\"";
+  }
+};
+
+class LambdaExpr : public Node {
+  const Node *Type;
+
+public:
+  LambdaExpr(const Node *Type_) : Node(KLambdaExpr), Type(Type_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Type); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "[]";
+    if (Type->getKind() == KClosureTypeName)
+      static_cast<const ClosureTypeName *>(Type)->printDeclarator(S);
+    S += "{...}";
+  }
+};
+
+class IntegerCastExpr : public Node {
+  // ty(integer)
+  const Node *Ty;
+  StringView Integer;
+
+public:
+  IntegerCastExpr(const Node *Ty_, StringView Integer_)
+      : Node(KIntegerCastExpr), Ty(Ty_), Integer(Integer_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Ty, Integer); }
+
+  void printLeft(OutputStream &S) const override {
+    S += "(";
+    Ty->print(S);
+    S += ")";
+    S += Integer;
+  }
+};
+
+class IntegerLiteral : public Node {
+  StringView Type;
+  StringView Value;
+
+public:
+  IntegerLiteral(StringView Type_, StringView Value_)
+      : Node(KIntegerLiteral), Type(Type_), Value(Value_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Type, Value); }
+
+  void printLeft(OutputStream &S) const override {
+    if (Type.size() > 3) {
+      S += "(";
+      S += Type;
+      S += ")";
+    }
+
+    if (Value[0] == 'n') {
+      S += "-";
+      S += Value.dropFront(1);
+    } else
+      S += Value;
+
+    if (Type.size() <= 3)
+      S += Type;
+  }
+};
+
+template <class Float> struct FloatData;
+
+namespace float_literal_impl {
+constexpr Node::Kind getFloatLiteralKind(float *) {
+  return Node::KFloatLiteral;
+}
+constexpr Node::Kind getFloatLiteralKind(double *) {
+  return Node::KDoubleLiteral;
+}
+constexpr Node::Kind getFloatLiteralKind(long double *) {
+  return Node::KLongDoubleLiteral;
+}
+}
+
+template <class Float> class FloatLiteralImpl : public Node {
+  const StringView Contents;
+
+  static constexpr Kind KindForClass =
+      float_literal_impl::getFloatLiteralKind((Float *)nullptr);
+
+public:
+  FloatLiteralImpl(StringView Contents_)
+      : Node(KindForClass), Contents(Contents_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Contents); }
+
+  void printLeft(OutputStream &s) const override {
+    const char *first = Contents.begin();
+    const char *last = Contents.end() + 1;
+
+    const size_t N = FloatData<Float>::mangled_size;
+    if (static_cast<std::size_t>(last - first) > N) {
+      last = first + N;
+      union {
+        Float value;
+        char buf[sizeof(Float)];
+      };
+      const char *t = first;
+      char *e = buf;
+      for (; t != last; ++t, ++e) {
+        unsigned d1 = isdigit(*t) ? static_cast<unsigned>(*t - '0')
+                                  : static_cast<unsigned>(*t - 'a' + 10);
+        ++t;
+        unsigned d0 = isdigit(*t) ? static_cast<unsigned>(*t - '0')
+                                  : static_cast<unsigned>(*t - 'a' + 10);
+        *e = static_cast<char>((d1 << 4) + d0);
+      }
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+      std::reverse(buf, e);
+#endif
+      char num[FloatData<Float>::max_demangled_size] = {0};
+      int n = snprintf(num, sizeof(num), FloatData<Float>::spec, value);
+      s += StringView(num, num + n);
+    }
+  }
+};
+
+using FloatLiteral = FloatLiteralImpl<float>;
+using DoubleLiteral = FloatLiteralImpl<double>;
+using LongDoubleLiteral = FloatLiteralImpl<long double>;
+
+/// Visit the node. Calls \c F(P), where \c P is the node cast to the
+/// appropriate derived class.
+template<typename Fn>
+void Node::visit(Fn F) const {
+  switch (K) {
+#define CASE(X) case K ## X: return F(static_cast<const X*>(this));
+    FOR_EACH_NODE_KIND(CASE)
+#undef CASE
+  }
+  assert(0 && "unknown mangling node kind");
+}
+
+/// Determine the kind of a node from its type.
+template<typename NodeT> struct NodeKind;
+#define SPECIALIZATION(X) \
+  template<> struct NodeKind<X> { \
+    static constexpr Node::Kind Kind = Node::K##X; \
+    static constexpr const char *name() { return #X; } \
+  };
+FOR_EACH_NODE_KIND(SPECIALIZATION)
+#undef SPECIALIZATION
+
+#undef FOR_EACH_NODE_KIND
+
+template <class T, size_t N>
+class PODSmallVector {
+  static_assert(std::is_pod<T>::value,
+                "T is required to be a plain old data type");
+
+  T* First;
+  T* Last;
+  T* Cap;
+  T Inline[N];
+
+  bool isInline() const { return First == Inline; }
+
+  void clearInline() {
+    First = Inline;
+    Last = Inline;
+    Cap = Inline + N;
+  }
+
+  void reserve(size_t NewCap) {
+    size_t S = size();
+    if (isInline()) {
+      auto* Tmp = static_cast<T*>(std::malloc(NewCap * sizeof(T)));
+      if (Tmp == nullptr)
+        std::terminate();
+      std::copy(First, Last, Tmp);
+      First = Tmp;
+    } else {
+      First = static_cast<T*>(std::realloc(First, NewCap * sizeof(T)));
+      if (First == nullptr)
+        std::terminate();
+    }
+    Last = First + S;
+    Cap = First + NewCap;
+  }
+
+public:
+  PODSmallVector() : First(Inline), Last(First), Cap(Inline + N) {}
+
+  PODSmallVector(const PODSmallVector&) = delete;
+  PODSmallVector& operator=(const PODSmallVector&) = delete;
+
+  PODSmallVector(PODSmallVector&& Other) : PODSmallVector() {
+    if (Other.isInline()) {
+      std::copy(Other.begin(), Other.end(), First);
+      Last = First + Other.size();
+      Other.clear();
+      return;
+    }
+
+    First = Other.First;
+    Last = Other.Last;
+    Cap = Other.Cap;
+    Other.clearInline();
+  }
+
+  PODSmallVector& operator=(PODSmallVector&& Other) {
+    if (Other.isInline()) {
+      if (!isInline()) {
+        std::free(First);
+        clearInline();
+      }
+      std::copy(Other.begin(), Other.end(), First);
+      Last = First + Other.size();
+      Other.clear();
+      return *this;
+    }
+
+    if (isInline()) {
+      First = Other.First;
+      Last = Other.Last;
+      Cap = Other.Cap;
+      Other.clearInline();
+      return *this;
+    }
+
+    std::swap(First, Other.First);
+    std::swap(Last, Other.Last);
+    std::swap(Cap, Other.Cap);
+    Other.clear();
+    return *this;
+  }
+
+  void push_back(const T& Elem) {
+    if (Last == Cap)
+      reserve(size() * 2);
+    *Last++ = Elem;
+  }
+
+  void pop_back() {
+    assert(Last != First && "Popping empty vector!");
+    --Last;
+  }
+
+  void dropBack(size_t Index) {
+    assert(Index <= size() && "dropBack() can't expand!");
+    Last = First + Index;
+  }
+
+  T* begin() { return First; }
+  T* end() { return Last; }
+
+  bool empty() const { return First == Last; }
+  size_t size() const { return static_cast<size_t>(Last - First); }
+  T& back() {
+    assert(Last != First && "Calling back() on empty vector!");
+    return *(Last - 1);
+  }
+  T& operator[](size_t Index) {
+    assert(Index < size() && "Invalid access!");
+    return *(begin() + Index);
+  }
+  void clear() { Last = First; }
+
+  ~PODSmallVector() {
+    if (!isInline())
+      std::free(First);
+  }
+};
+
+template <typename Derived, typename Alloc> struct AbstractManglingParser {
+  const char *First;
+  const char *Last;
+
+  // Name stack, this is used by the parser to hold temporary names that were
+  // parsed. The parser collapses multiple names into new nodes to construct
+  // the AST. Once the parser is finished, names.size() == 1.
+  PODSmallVector<Node *, 32> Names;
+
+  // Substitution table. Itanium supports name substitutions as a means of
+  // compression. The string "S42_" refers to the 44nd entry (base-36) in this
+  // table.
+  PODSmallVector<Node *, 32> Subs;
+
+  using TemplateParamList = PODSmallVector<Node *, 8>;
+
+  class ScopedTemplateParamList {
+    AbstractManglingParser *Parser;
+    size_t OldNumTemplateParamLists;
+    TemplateParamList Params;
+
+  public:
+    ScopedTemplateParamList(AbstractManglingParser *Parser)
+        : Parser(Parser),
+          OldNumTemplateParamLists(Parser->TemplateParams.size()) {
+      Parser->TemplateParams.push_back(&Params);
+    }
+    ~ScopedTemplateParamList() {
+      assert(Parser->TemplateParams.size() >= OldNumTemplateParamLists);
+      Parser->TemplateParams.dropBack(OldNumTemplateParamLists);
+    }
+  };
+
+  // Template parameter table. Like the above, but referenced like "T42_".
+  // This has a smaller size compared to Subs and Names because it can be
+  // stored on the stack.
+  TemplateParamList OuterTemplateParams;
+
+  // Lists of template parameters indexed by template parameter depth,
+  // referenced like "TL2_4_". If nonempty, element 0 is always
+  // OuterTemplateParams; inner elements are always template parameter lists of
+  // lambda expressions. For a generic lambda with no explicit template
+  // parameter list, the corresponding parameter list pointer will be null.
+  PODSmallVector<TemplateParamList *, 4> TemplateParams;
+
+  // Set of unresolved forward <template-param> references. These can occur in a
+  // conversion operator's type, and are resolved in the enclosing <encoding>.
+  PODSmallVector<ForwardTemplateReference *, 4> ForwardTemplateRefs;
+
+  bool TryToParseTemplateArgs = true;
+  bool PermitForwardTemplateReferences = false;
+  size_t ParsingLambdaParamsAtLevel = (size_t)-1;
+
+  unsigned NumSyntheticTemplateParameters[3] = {};
+
+  Alloc ASTAllocator;
+
+  AbstractManglingParser(const char *First_, const char *Last_)
+      : First(First_), Last(Last_) {}
+
+  Derived &getDerived() { return static_cast<Derived &>(*this); }
+
+  void reset(const char *First_, const char *Last_) {
+    First = First_;
+    Last = Last_;
+    Names.clear();
+    Subs.clear();
+    TemplateParams.clear();
+    ParsingLambdaParamsAtLevel = (size_t)-1;
+    TryToParseTemplateArgs = true;
+    PermitForwardTemplateReferences = false;
+    for (int I = 0; I != 3; ++I)
+      NumSyntheticTemplateParameters[I] = 0;
+    ASTAllocator.reset();
+  }
+
+  template <class T, class... Args> Node *make(Args &&... args) {
+    return ASTAllocator.template makeNode<T>(std::forward<Args>(args)...);
+  }
+
+  template <class It> NodeArray makeNodeArray(It begin, It end) {
+    size_t sz = static_cast<size_t>(end - begin);
+    void *mem = ASTAllocator.allocateNodeArray(sz);
+    Node **data = new (mem) Node *[sz];
+    std::copy(begin, end, data);
+    return NodeArray(data, sz);
+  }
+
+  NodeArray popTrailingNodeArray(size_t FromPosition) {
+    assert(FromPosition <= Names.size());
+    NodeArray res =
+        makeNodeArray(Names.begin() + (long)FromPosition, Names.end());
+    Names.dropBack(FromPosition);
+    return res;
+  }
+
+  bool consumeIf(StringView S) {
+    if (StringView(First, Last).startsWith(S)) {
+      First += S.size();
+      return true;
+    }
+    return false;
+  }
+
+  bool consumeIf(char C) {
+    if (First != Last && *First == C) {
+      ++First;
+      return true;
+    }
+    return false;
+  }
+
+  char consume() { return First != Last ? *First++ : '\0'; }
+
+  char look(unsigned Lookahead = 0) {
+    if (static_cast<size_t>(Last - First) <= Lookahead)
+      return '\0';
+    return First[Lookahead];
+  }
+
+  size_t numLeft() const { return static_cast<size_t>(Last - First); }
+
+  StringView parseNumber(bool AllowNegative = false);
+  Qualifiers parseCVQualifiers();
+  bool parsePositiveInteger(size_t *Out);
+  StringView parseBareSourceName();
+
+  bool parseSeqId(size_t *Out);
+  Node *parseSubstitution();
+  Node *parseTemplateParam();
+  Node *parseTemplateParamDecl();
+  Node *parseTemplateArgs(bool TagTemplates = false);
+  Node *parseTemplateArg();
+
+  /// Parse the <expr> production.
+  Node *parseExpr();
+  Node *parsePrefixExpr(StringView Kind);
+  Node *parseBinaryExpr(StringView Kind);
+  Node *parseIntegerLiteral(StringView Lit);
+  Node *parseExprPrimary();
+  template <class Float> Node *parseFloatingLiteral();
+  Node *parseFunctionParam();
+  Node *parseNewExpr();
+  Node *parseConversionExpr();
+  Node *parseBracedExpr();
+  Node *parseFoldExpr();
+
+  /// Parse the <type> production.
+  Node *parseType();
+  Node *parseFunctionType();
+  Node *parseVectorType();
+  Node *parseDecltype();
+  Node *parseArrayType();
+  Node *parsePointerToMemberType();
+  Node *parseClassEnumType();
+  Node *parseQualifiedType();
+
+  Node *parseEncoding();
+  bool parseCallOffset();
+  Node *parseSpecialName();
+
+  /// Holds some extra information about a <name> that is being parsed. This
+  /// information is only pertinent if the <name> refers to an <encoding>.
+  struct NameState {
+    bool CtorDtorConversion = false;
+    bool EndsWithTemplateArgs = false;
+    Qualifiers CVQualifiers = QualNone;
+    FunctionRefQual ReferenceQualifier = FrefQualNone;
+    size_t ForwardTemplateRefsBegin;
+
+    NameState(AbstractManglingParser *Enclosing)
+        : ForwardTemplateRefsBegin(Enclosing->ForwardTemplateRefs.size()) {}
+  };
+
+  bool resolveForwardTemplateRefs(NameState &State) {
+    size_t I = State.ForwardTemplateRefsBegin;
+    size_t E = ForwardTemplateRefs.size();
+    for (; I < E; ++I) {
+      size_t Idx = ForwardTemplateRefs[I]->Index;
+      if (TemplateParams.empty() || !TemplateParams[0] ||
+          Idx >= TemplateParams[0]->size())
+        return true;
+      ForwardTemplateRefs[I]->Ref = (*TemplateParams[0])[Idx];
+    }
+    ForwardTemplateRefs.dropBack(State.ForwardTemplateRefsBegin);
+    return false;
+  }
+
+  /// Parse the <name> production>
+  Node *parseName(NameState *State = nullptr);
+  Node *parseLocalName(NameState *State);
+  Node *parseOperatorName(NameState *State);
+  Node *parseUnqualifiedName(NameState *State);
+  Node *parseUnnamedTypeName(NameState *State);
+  Node *parseSourceName(NameState *State);
+  Node *parseUnscopedName(NameState *State);
+  Node *parseNestedName(NameState *State);
+  Node *parseCtorDtorName(Node *&SoFar, NameState *State);
+
+  Node *parseAbiTags(Node *N);
+
+  /// Parse the <unresolved-name> production.
+  Node *parseUnresolvedName();
+  Node *parseSimpleId();
+  Node *parseBaseUnresolvedName();
+  Node *parseUnresolvedType();
+  Node *parseDestructorName();
+
+  /// Top-level entry point into the parser.
+  Node *parse();
+};
+
+const char* parse_discriminator(const char* first, const char* last);
+
+// <name> ::= <nested-name> // N
+//        ::= <local-name> # See Scope Encoding below  // Z
+//        ::= <unscoped-template-name> <template-args>
+//        ::= <unscoped-name>
+//
+// <unscoped-template-name> ::= <unscoped-name>
+//                          ::= <substitution>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseName(NameState *State) {
+  consumeIf('L'); // extension
+
+  if (look() == 'N')
+    return getDerived().parseNestedName(State);
+  if (look() == 'Z')
+    return getDerived().parseLocalName(State);
+
+  //        ::= <unscoped-template-name> <template-args>
+  if (look() == 'S' && look(1) != 't') {
+    Node *S = getDerived().parseSubstitution();
+    if (S == nullptr)
+      return nullptr;
+    if (look() != 'I')
+      return nullptr;
+    Node *TA = getDerived().parseTemplateArgs(State != nullptr);
+    if (TA == nullptr)
+      return nullptr;
+    if (State) State->EndsWithTemplateArgs = true;
+    return make<NameWithTemplateArgs>(S, TA);
+  }
+
+  Node *N = getDerived().parseUnscopedName(State);
+  if (N == nullptr)
+    return nullptr;
+  //        ::= <unscoped-template-name> <template-args>
+  if (look() == 'I') {
+    Subs.push_back(N);
+    Node *TA = getDerived().parseTemplateArgs(State != nullptr);
+    if (TA == nullptr)
+      return nullptr;
+    if (State) State->EndsWithTemplateArgs = true;
+    return make<NameWithTemplateArgs>(N, TA);
+  }
+  //        ::= <unscoped-name>
+  return N;
+}
+
+// <local-name> := Z <function encoding> E <entity name> [<discriminator>]
+//              := Z <function encoding> E s [<discriminator>]
+//              := Z <function encoding> Ed [ <parameter number> ] _ <entity name>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseLocalName(NameState *State) {
+  if (!consumeIf('Z'))
+    return nullptr;
+  Node *Encoding = getDerived().parseEncoding();
+  if (Encoding == nullptr || !consumeIf('E'))
+    return nullptr;
+
+  if (consumeIf('s')) {
+    First = parse_discriminator(First, Last);
+    auto *StringLitName = make<NameType>("string literal");
+    if (!StringLitName)
+      return nullptr;
+    return make<LocalName>(Encoding, StringLitName);
+  }
+
+  if (consumeIf('d')) {
+    parseNumber(true);
+    if (!consumeIf('_'))
+      return nullptr;
+    Node *N = getDerived().parseName(State);
+    if (N == nullptr)
+      return nullptr;
+    return make<LocalName>(Encoding, N);
+  }
+
+  Node *Entity = getDerived().parseName(State);
+  if (Entity == nullptr)
+    return nullptr;
+  First = parse_discriminator(First, Last);
+  return make<LocalName>(Encoding, Entity);
+}
+
+// <unscoped-name> ::= <unqualified-name>
+//                 ::= St <unqualified-name>   # ::std::
+// extension       ::= StL<unqualified-name>
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseUnscopedName(NameState *State) {
+  if (consumeIf("StL") || consumeIf("St")) {
+    Node *R = getDerived().parseUnqualifiedName(State);
+    if (R == nullptr)
+      return nullptr;
+    return make<StdQualifiedName>(R);
+  }
+  return getDerived().parseUnqualifiedName(State);
+}
+
+// <unqualified-name> ::= <operator-name> [abi-tags]
+//                    ::= <ctor-dtor-name>
+//                    ::= <source-name>
+//                    ::= <unnamed-type-name>
+//                    ::= DC <source-name>+ E      # structured binding declaration
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseUnqualifiedName(NameState *State) {
+  // <ctor-dtor-name>s are special-cased in parseNestedName().
+  Node *Result;
+  if (look() == 'U')
+    Result = getDerived().parseUnnamedTypeName(State);
+  else if (look() >= '1' && look() <= '9')
+    Result = getDerived().parseSourceName(State);
+  else if (consumeIf("DC")) {
+    size_t BindingsBegin = Names.size();
+    do {
+      Node *Binding = getDerived().parseSourceName(State);
+      if (Binding == nullptr)
+        return nullptr;
+      Names.push_back(Binding);
+    } while (!consumeIf('E'));
+    Result = make<StructuredBindingName>(popTrailingNodeArray(BindingsBegin));
+  } else
+    Result = getDerived().parseOperatorName(State);
+  if (Result != nullptr)
+    Result = getDerived().parseAbiTags(Result);
+  return Result;
+}
+
+// <unnamed-type-name> ::= Ut [<nonnegative number>] _
+//                     ::= <closure-type-name>
+//
+// <closure-type-name> ::= Ul <lambda-sig> E [ <nonnegative number> ] _
+//
+// <lambda-sig> ::= <parameter type>+  # Parameter types or "v" if the lambda has no parameters
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseUnnamedTypeName(NameState *State) {
+  // <template-params> refer to the innermost <template-args>. Clear out any
+  // outer args that we may have inserted into TemplateParams.
+  if (State != nullptr)
+    TemplateParams.clear();
+
+  if (consumeIf("Ut")) {
+    StringView Count = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    return make<UnnamedTypeName>(Count);
+  }
+  if (consumeIf("Ul")) {
+    SwapAndRestore<size_t> SwapParams(ParsingLambdaParamsAtLevel,
+                                      TemplateParams.size());
+    ScopedTemplateParamList LambdaTemplateParams(this);
+
+    size_t ParamsBegin = Names.size();
+    while (look() == 'T' &&
+           StringView("yptn").find(look(1)) != StringView::npos) {
+      Node *T = parseTemplateParamDecl();
+      if (!T)
+        return nullptr;
+      Names.push_back(T);
+    }
+    NodeArray TempParams = popTrailingNodeArray(ParamsBegin);
+
+    // FIXME: If TempParams is empty and none of the function parameters
+    // includes 'auto', we should remove LambdaTemplateParams from the
+    // TemplateParams list. Unfortunately, we don't find out whether there are
+    // any 'auto' parameters until too late in an example such as:
+    //
+    //   template<typename T> void f(
+    //       decltype([](decltype([]<typename T>(T v) {}),
+    //                   auto) {})) {}
+    //   template<typename T> void f(
+    //       decltype([](decltype([]<typename T>(T w) {}),
+    //                   int) {})) {}
+    //
+    // Here, the type of v is at level 2 but the type of w is at level 1. We
+    // don't find this out until we encounter the type of the next parameter.
+    //
+    // However, compilers can't actually cope with the former example in
+    // practice, and it's likely to be made ill-formed in future, so we don't
+    // need to support it here.
+    //
+    // If we encounter an 'auto' in the function parameter types, we will
+    // recreate a template parameter scope for it, but any intervening lambdas
+    // will be parsed in the 'wrong' template parameter depth.
+    if (TempParams.empty())
+      TemplateParams.pop_back();
+
+    if (!consumeIf("vE")) {
+      do {
+        Node *P = getDerived().parseType();
+        if (P == nullptr)
+          return nullptr;
+        Names.push_back(P);
+      } while (!consumeIf('E'));
+    }
+    NodeArray Params = popTrailingNodeArray(ParamsBegin);
+
+    StringView Count = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    return make<ClosureTypeName>(TempParams, Params, Count);
+  }
+  if (consumeIf("Ub")) {
+    (void)parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    return make<NameType>("'block-literal'");
+  }
+  return nullptr;
+}
+
+// <source-name> ::= <positive length number> <identifier>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseSourceName(NameState *) {
+  size_t Length = 0;
+  if (parsePositiveInteger(&Length))
+    return nullptr;
+  if (numLeft() < Length || Length == 0)
+    return nullptr;
+  StringView Name(First, First + Length);
+  First += Length;
+  if (Name.startsWith("_GLOBAL__N"))
+    return make<NameType>("(anonymous namespace)");
+  return make<NameType>(Name);
+}
+
+//   <operator-name> ::= aa    # &&
+//                   ::= ad    # & (unary)
+//                   ::= an    # &
+//                   ::= aN    # &=
+//                   ::= aS    # =
+//                   ::= cl    # ()
+//                   ::= cm    # ,
+//                   ::= co    # ~
+//                   ::= cv <type>    # (cast)
+//                   ::= da    # delete[]
+//                   ::= de    # * (unary)
+//                   ::= dl    # delete
+//                   ::= dv    # /
+//                   ::= dV    # /=
+//                   ::= eo    # ^
+//                   ::= eO    # ^=
+//                   ::= eq    # ==
+//                   ::= ge    # >=
+//                   ::= gt    # >
+//                   ::= ix    # []
+//                   ::= le    # <=
+//                   ::= li <source-name>  # operator ""
+//                   ::= ls    # <<
+//                   ::= lS    # <<=
+//                   ::= lt    # <
+//                   ::= mi    # -
+//                   ::= mI    # -=
+//                   ::= ml    # *
+//                   ::= mL    # *=
+//                   ::= mm    # -- (postfix in <expression> context)
+//                   ::= na    # new[]
+//                   ::= ne    # !=
+//                   ::= ng    # - (unary)
+//                   ::= nt    # !
+//                   ::= nw    # new
+//                   ::= oo    # ||
+//                   ::= or    # |
+//                   ::= oR    # |=
+//                   ::= pm    # ->*
+//                   ::= pl    # +
+//                   ::= pL    # +=
+//                   ::= pp    # ++ (postfix in <expression> context)
+//                   ::= ps    # + (unary)
+//                   ::= pt    # ->
+//                   ::= qu    # ?
+//                   ::= rm    # %
+//                   ::= rM    # %=
+//                   ::= rs    # >>
+//                   ::= rS    # >>=
+//                   ::= ss    # <=> C++2a
+//                   ::= v <digit> <source-name>        # vendor extended operator
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseOperatorName(NameState *State) {
+  switch (look()) {
+  case 'a':
+    switch (look(1)) {
+    case 'a':
+      First += 2;
+      return make<NameType>("operator&&");
+    case 'd':
+    case 'n':
+      First += 2;
+      return make<NameType>("operator&");
+    case 'N':
+      First += 2;
+      return make<NameType>("operator&=");
+    case 'S':
+      First += 2;
+      return make<NameType>("operator=");
+    }
+    return nullptr;
+  case 'c':
+    switch (look(1)) {
+    case 'l':
+      First += 2;
+      return make<NameType>("operator()");
+    case 'm':
+      First += 2;
+      return make<NameType>("operator,");
+    case 'o':
+      First += 2;
+      return make<NameType>("operator~");
+    //                   ::= cv <type>    # (cast)
+    case 'v': {
+      First += 2;
+      SwapAndRestore<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);
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      if (State) State->CtorDtorConversion = true;
+      return make<ConversionOperatorType>(Ty);
+    }
+    }
+    return nullptr;
+  case 'd':
+    switch (look(1)) {
+    case 'a':
+      First += 2;
+      return make<NameType>("operator delete[]");
+    case 'e':
+      First += 2;
+      return make<NameType>("operator*");
+    case 'l':
+      First += 2;
+      return make<NameType>("operator delete");
+    case 'v':
+      First += 2;
+      return make<NameType>("operator/");
+    case 'V':
+      First += 2;
+      return make<NameType>("operator/=");
+    }
+    return nullptr;
+  case 'e':
+    switch (look(1)) {
+    case 'o':
+      First += 2;
+      return make<NameType>("operator^");
+    case 'O':
+      First += 2;
+      return make<NameType>("operator^=");
+    case 'q':
+      First += 2;
+      return make<NameType>("operator==");
+    }
+    return nullptr;
+  case 'g':
+    switch (look(1)) {
+    case 'e':
+      First += 2;
+      return make<NameType>("operator>=");
+    case 't':
+      First += 2;
+      return make<NameType>("operator>");
+    }
+    return nullptr;
+  case 'i':
+    if (look(1) == 'x') {
+      First += 2;
+      return make<NameType>("operator[]");
+    }
+    return nullptr;
+  case 'l':
+    switch (look(1)) {
+    case 'e':
+      First += 2;
+      return make<NameType>("operator<=");
+    //                   ::= li <source-name>  # operator ""
+    case 'i': {
+      First += 2;
+      Node *SN = getDerived().parseSourceName(State);
+      if (SN == nullptr)
+        return nullptr;
+      return make<LiteralOperator>(SN);
+    }
+    case 's':
+      First += 2;
+      return make<NameType>("operator<<");
+    case 'S':
+      First += 2;
+      return make<NameType>("operator<<=");
+    case 't':
+      First += 2;
+      return make<NameType>("operator<");
+    }
+    return nullptr;
+  case 'm':
+    switch (look(1)) {
+    case 'i':
+      First += 2;
+      return make<NameType>("operator-");
+    case 'I':
+      First += 2;
+      return make<NameType>("operator-=");
+    case 'l':
+      First += 2;
+      return make<NameType>("operator*");
+    case 'L':
+      First += 2;
+      return make<NameType>("operator*=");
+    case 'm':
+      First += 2;
+      return make<NameType>("operator--");
+    }
+    return nullptr;
+  case 'n':
+    switch (look(1)) {
+    case 'a':
+      First += 2;
+      return make<NameType>("operator new[]");
+    case 'e':
+      First += 2;
+      return make<NameType>("operator!=");
+    case 'g':
+      First += 2;
+      return make<NameType>("operator-");
+    case 't':
+      First += 2;
+      return make<NameType>("operator!");
+    case 'w':
+      First += 2;
+      return make<NameType>("operator new");
+    }
+    return nullptr;
+  case 'o':
+    switch (look(1)) {
+    case 'o':
+      First += 2;
+      return make<NameType>("operator||");
+    case 'r':
+      First += 2;
+      return make<NameType>("operator|");
+    case 'R':
+      First += 2;
+      return make<NameType>("operator|=");
+    }
+    return nullptr;
+  case 'p':
+    switch (look(1)) {
+    case 'm':
+      First += 2;
+      return make<NameType>("operator->*");
+    case 'l':
+      First += 2;
+      return make<NameType>("operator+");
+    case 'L':
+      First += 2;
+      return make<NameType>("operator+=");
+    case 'p':
+      First += 2;
+      return make<NameType>("operator++");
+    case 's':
+      First += 2;
+      return make<NameType>("operator+");
+    case 't':
+      First += 2;
+      return make<NameType>("operator->");
+    }
+    return nullptr;
+  case 'q':
+    if (look(1) == 'u') {
+      First += 2;
+      return make<NameType>("operator?");
+    }
+    return nullptr;
+  case 'r':
+    switch (look(1)) {
+    case 'm':
+      First += 2;
+      return make<NameType>("operator%");
+    case 'M':
+      First += 2;
+      return make<NameType>("operator%=");
+    case 's':
+      First += 2;
+      return make<NameType>("operator>>");
+    case 'S':
+      First += 2;
+      return make<NameType>("operator>>=");
+    }
+    return nullptr;
+  case 's':
+    if (look(1) == 's') {
+      First += 2;
+      return make<NameType>("operator<=>");
+    }
+    return nullptr;
+  // ::= v <digit> <source-name>        # vendor extended operator
+  case 'v':
+    if (std::isdigit(look(1))) {
+      First += 2;
+      Node *SN = getDerived().parseSourceName(State);
+      if (SN == nullptr)
+        return nullptr;
+      return make<ConversionOperatorType>(SN);
+    }
+    return nullptr;
+  }
+  return nullptr;
+}
+
+// <ctor-dtor-name> ::= C1  # complete object constructor
+//                  ::= C2  # base object constructor
+//                  ::= C3  # complete object allocating constructor
+//   extension      ::= C4  # gcc old-style "[unified]" constructor
+//   extension      ::= C5  # the COMDAT used for ctors
+//                  ::= D0  # deleting destructor
+//                  ::= D1  # complete object destructor
+//                  ::= D2  # base object destructor
+//   extension      ::= D4  # gcc old-style "[unified]" destructor
+//   extension      ::= D5  # the COMDAT used for dtors
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseCtorDtorName(Node *&SoFar,
+                                                          NameState *State) {
+  if (SoFar->getKind() == Node::KSpecialSubstitution) {
+    auto SSK = static_cast<SpecialSubstitution *>(SoFar)->SSK;
+    switch (SSK) {
+    case SpecialSubKind::string:
+    case SpecialSubKind::istream:
+    case SpecialSubKind::ostream:
+    case SpecialSubKind::iostream:
+      SoFar = make<ExpandedSpecialSubstitution>(SSK);
+      if (!SoFar)
+        return nullptr;
+      break;
+    default:
+      break;
+    }
+  }
+
+  if (consumeIf('C')) {
+    bool IsInherited = consumeIf('I');
+    if (look() != '1' && look() != '2' && look() != '3' && look() != '4' &&
+        look() != '5')
+      return nullptr;
+    int Variant = look() - '0';
+    ++First;
+    if (State) State->CtorDtorConversion = true;
+    if (IsInherited) {
+      if (getDerived().parseName(State) == nullptr)
+        return nullptr;
+    }
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/false, Variant);
+  }
+
+  if (look() == 'D' && (look(1) == '0' || look(1) == '1' || look(1) == '2' ||
+                        look(1) == '4' || look(1) == '5')) {
+    int Variant = look(1) - '0';
+    First += 2;
+    if (State) State->CtorDtorConversion = true;
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/true, Variant);
+  }
+
+  return nullptr;
+}
+
+// <nested-name> ::= N [<CV-Qualifiers>] [<ref-qualifier>] <prefix> <unqualified-name> E
+//               ::= N [<CV-Qualifiers>] [<ref-qualifier>] <template-prefix> <template-args> E
+//
+// <prefix> ::= <prefix> <unqualified-name>
+//          ::= <template-prefix> <template-args>
+//          ::= <template-param>
+//          ::= <decltype>
+//          ::= # empty
+//          ::= <substitution>
+//          ::= <prefix> <data-member-prefix>
+//  extension ::= L
+//
+// <data-member-prefix> := <member source-name> [<template-args>] M
+//
+// <template-prefix> ::= <prefix> <template unqualified-name>
+//                   ::= <template-param>
+//                   ::= <substitution>
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseNestedName(NameState *State) {
+  if (!consumeIf('N'))
+    return nullptr;
+
+  Qualifiers CVTmp = parseCVQualifiers();
+  if (State) State->CVQualifiers = CVTmp;
+
+  if (consumeIf('O')) {
+    if (State) State->ReferenceQualifier = FrefQualRValue;
+  } else if (consumeIf('R')) {
+    if (State) State->ReferenceQualifier = FrefQualLValue;
+  } else
+    if (State) State->ReferenceQualifier = FrefQualNone;
+
+  Node *SoFar = nullptr;
+  auto PushComponent = [&](Node *Comp) {
+    if (!Comp) return false;
+    if (SoFar) SoFar = make<NestedName>(SoFar, Comp);
+    else       SoFar = Comp;
+    if (State) State->EndsWithTemplateArgs = false;
+    return SoFar != nullptr;
+  };
+
+  if (consumeIf("St")) {
+    SoFar = make<NameType>("std");
+    if (!SoFar)
+      return nullptr;
+  }
+
+  while (!consumeIf('E')) {
+    consumeIf('L'); // extension
+
+    // <data-member-prefix> := <member source-name> [<template-args>] M
+    if (consumeIf('M')) {
+      if (SoFar == nullptr)
+        return nullptr;
+      continue;
+    }
+
+    //          ::= <template-param>
+    if (look() == 'T') {
+      if (!PushComponent(getDerived().parseTemplateParam()))
+        return nullptr;
+      Subs.push_back(SoFar);
+      continue;
+    }
+
+    //          ::= <template-prefix> <template-args>
+    if (look() == 'I') {
+      Node *TA = getDerived().parseTemplateArgs(State != nullptr);
+      if (TA == nullptr || SoFar == nullptr)
+        return nullptr;
+      SoFar = make<NameWithTemplateArgs>(SoFar, TA);
+      if (!SoFar)
+        return nullptr;
+      if (State) State->EndsWithTemplateArgs = true;
+      Subs.push_back(SoFar);
+      continue;
+    }
+
+    //          ::= <decltype>
+    if (look() == 'D' && (look(1) == 't' || look(1) == 'T')) {
+      if (!PushComponent(getDerived().parseDecltype()))
+        return nullptr;
+      Subs.push_back(SoFar);
+      continue;
+    }
+
+    //          ::= <substitution>
+    if (look() == 'S' && look(1) != 't') {
+      Node *S = getDerived().parseSubstitution();
+      if (!PushComponent(S))
+        return nullptr;
+      if (SoFar != S)
+        Subs.push_back(S);
+      continue;
+    }
+
+    // Parse an <unqualified-name> thats actually a <ctor-dtor-name>.
+    if (look() == 'C' || (look() == 'D' && look(1) != 'C')) {
+      if (SoFar == nullptr)
+        return nullptr;
+      if (!PushComponent(getDerived().parseCtorDtorName(SoFar, State)))
+        return nullptr;
+      SoFar = getDerived().parseAbiTags(SoFar);
+      if (SoFar == nullptr)
+        return nullptr;
+      Subs.push_back(SoFar);
+      continue;
+    }
+
+    //          ::= <prefix> <unqualified-name>
+    if (!PushComponent(getDerived().parseUnqualifiedName(State)))
+      return nullptr;
+    Subs.push_back(SoFar);
+  }
+
+  if (SoFar == nullptr || Subs.empty())
+    return nullptr;
+
+  Subs.pop_back();
+  return SoFar;
+}
+
+// <simple-id> ::= <source-name> [ <template-args> ]
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseSimpleId() {
+  Node *SN = getDerived().parseSourceName(/*NameState=*/nullptr);
+  if (SN == nullptr)
+    return nullptr;
+  if (look() == 'I') {
+    Node *TA = getDerived().parseTemplateArgs();
+    if (TA == nullptr)
+      return nullptr;
+    return make<NameWithTemplateArgs>(SN, TA);
+  }
+  return SN;
+}
+
+// <destructor-name> ::= <unresolved-type>  # e.g., ~T or ~decltype(f())
+//                   ::= <simple-id>        # e.g., ~A<2*N>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseDestructorName() {
+  Node *Result;
+  if (std::isdigit(look()))
+    Result = getDerived().parseSimpleId();
+  else
+    Result = getDerived().parseUnresolvedType();
+  if (Result == nullptr)
+    return nullptr;
+  return make<DtorName>(Result);
+}
+
+// <unresolved-type> ::= <template-param>
+//                   ::= <decltype>
+//                   ::= <substitution>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseUnresolvedType() {
+  if (look() == 'T') {
+    Node *TP = getDerived().parseTemplateParam();
+    if (TP == nullptr)
+      return nullptr;
+    Subs.push_back(TP);
+    return TP;
+  }
+  if (look() == 'D') {
+    Node *DT = getDerived().parseDecltype();
+    if (DT == nullptr)
+      return nullptr;
+    Subs.push_back(DT);
+    return DT;
+  }
+  return getDerived().parseSubstitution();
+}
+
+// <base-unresolved-name> ::= <simple-id>                                # unresolved name
+//          extension     ::= <operator-name>                            # unresolved operator-function-id
+//          extension     ::= <operator-name> <template-args>            # unresolved operator template-id
+//                        ::= on <operator-name>                         # unresolved operator-function-id
+//                        ::= on <operator-name> <template-args>         # unresolved operator template-id
+//                        ::= dn <destructor-name>                       # destructor or pseudo-destructor;
+//                                                                         # e.g. ~X or ~X<N-1>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseBaseUnresolvedName() {
+  if (std::isdigit(look()))
+    return getDerived().parseSimpleId();
+
+  if (consumeIf("dn"))
+    return getDerived().parseDestructorName();
+
+  consumeIf("on");
+
+  Node *Oper = getDerived().parseOperatorName(/*NameState=*/nullptr);
+  if (Oper == nullptr)
+    return nullptr;
+  if (look() == 'I') {
+    Node *TA = getDerived().parseTemplateArgs();
+    if (TA == nullptr)
+      return nullptr;
+    return make<NameWithTemplateArgs>(Oper, TA);
+  }
+  return Oper;
+}
+
+// <unresolved-name>
+//  extension        ::= srN <unresolved-type> [<template-args>] <unresolved-qualifier-level>* E <base-unresolved-name>
+//                   ::= [gs] <base-unresolved-name>                     # x or (with "gs") ::x
+//                   ::= [gs] sr <unresolved-qualifier-level>+ E <base-unresolved-name>
+//                                                                       # A::x, N::y, A<T>::z; "gs" means leading "::"
+//                   ::= sr <unresolved-type> <base-unresolved-name>     # T::x / decltype(p)::x
+//  extension        ::= sr <unresolved-type> <template-args> <base-unresolved-name>
+//                                                                       # T::N::x /decltype(p)::N::x
+//  (ignored)        ::= srN <unresolved-type>  <unresolved-qualifier-level>+ E <base-unresolved-name>
+//
+// <unresolved-qualifier-level> ::= <simple-id>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseUnresolvedName() {
+  Node *SoFar = nullptr;
+
+  // srN <unresolved-type> [<template-args>] <unresolved-qualifier-level>* E <base-unresolved-name>
+  // srN <unresolved-type>                   <unresolved-qualifier-level>+ E <base-unresolved-name>
+  if (consumeIf("srN")) {
+    SoFar = getDerived().parseUnresolvedType();
+    if (SoFar == nullptr)
+      return nullptr;
+
+    if (look() == 'I') {
+      Node *TA = getDerived().parseTemplateArgs();
+      if (TA == nullptr)
+        return nullptr;
+      SoFar = make<NameWithTemplateArgs>(SoFar, TA);
+      if (!SoFar)
+        return nullptr;
+    }
+
+    while (!consumeIf('E')) {
+      Node *Qual = getDerived().parseSimpleId();
+      if (Qual == nullptr)
+        return nullptr;
+      SoFar = make<QualifiedName>(SoFar, Qual);
+      if (!SoFar)
+        return nullptr;
+    }
+
+    Node *Base = getDerived().parseBaseUnresolvedName();
+    if (Base == nullptr)
+      return nullptr;
+    return make<QualifiedName>(SoFar, Base);
+  }
+
+  bool Global = consumeIf("gs");
+
+  // [gs] <base-unresolved-name>                     # x or (with "gs") ::x
+  if (!consumeIf("sr")) {
+    SoFar = getDerived().parseBaseUnresolvedName();
+    if (SoFar == nullptr)
+      return nullptr;
+    if (Global)
+      SoFar = make<GlobalQualifiedName>(SoFar);
+    return SoFar;
+  }
+
+  // [gs] sr <unresolved-qualifier-level>+ E   <base-unresolved-name>
+  if (std::isdigit(look())) {
+    do {
+      Node *Qual = getDerived().parseSimpleId();
+      if (Qual == nullptr)
+        return nullptr;
+      if (SoFar)
+        SoFar = make<QualifiedName>(SoFar, Qual);
+      else if (Global)
+        SoFar = make<GlobalQualifiedName>(Qual);
+      else
+        SoFar = Qual;
+      if (!SoFar)
+        return nullptr;
+    } while (!consumeIf('E'));
+  }
+  //      sr <unresolved-type>                 <base-unresolved-name>
+  //      sr <unresolved-type> <template-args> <base-unresolved-name>
+  else {
+    SoFar = getDerived().parseUnresolvedType();
+    if (SoFar == nullptr)
+      return nullptr;
+
+    if (look() == 'I') {
+      Node *TA = getDerived().parseTemplateArgs();
+      if (TA == nullptr)
+        return nullptr;
+      SoFar = make<NameWithTemplateArgs>(SoFar, TA);
+      if (!SoFar)
+        return nullptr;
+    }
+  }
+
+  assert(SoFar != nullptr);
+
+  Node *Base = getDerived().parseBaseUnresolvedName();
+  if (Base == nullptr)
+    return nullptr;
+  return make<QualifiedName>(SoFar, Base);
+}
+
+// <abi-tags> ::= <abi-tag> [<abi-tags>]
+// <abi-tag> ::= B <source-name>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseAbiTags(Node *N) {
+  while (consumeIf('B')) {
+    StringView SN = parseBareSourceName();
+    if (SN.empty())
+      return nullptr;
+    N = make<AbiTagAttr>(N, SN);
+    if (!N)
+      return nullptr;
+  }
+  return N;
+}
+
+// <number> ::= [n] <non-negative decimal integer>
+template <typename Alloc, typename Derived>
+StringView
+AbstractManglingParser<Alloc, Derived>::parseNumber(bool AllowNegative) {
+  const char *Tmp = First;
+  if (AllowNegative)
+    consumeIf('n');
+  if (numLeft() == 0 || !std::isdigit(*First))
+    return StringView();
+  while (numLeft() != 0 && std::isdigit(*First))
+    ++First;
+  return StringView(Tmp, First);
+}
+
+// <positive length number> ::= [0-9]*
+template <typename Alloc, typename Derived>
+bool AbstractManglingParser<Alloc, Derived>::parsePositiveInteger(size_t *Out) {
+  *Out = 0;
+  if (look() < '0' || look() > '9')
+    return true;
+  while (look() >= '0' && look() <= '9') {
+    *Out *= 10;
+    *Out += static_cast<size_t>(consume() - '0');
+  }
+  return false;
+}
+
+template <typename Alloc, typename Derived>
+StringView AbstractManglingParser<Alloc, Derived>::parseBareSourceName() {
+  size_t Int = 0;
+  if (parsePositiveInteger(&Int) || numLeft() < Int)
+    return StringView();
+  StringView R(First, First + Int);
+  First += Int;
+  return R;
+}
+
+// <function-type> ::= [<CV-qualifiers>] [<exception-spec>] [Dx] F [Y] <bare-function-type> [<ref-qualifier>] E
+//
+// <exception-spec> ::= Do                # non-throwing exception-specification (e.g., noexcept, throw())
+//                  ::= DO <expression> E # computed (instantiation-dependent) noexcept
+//                  ::= Dw <type>+ E      # dynamic exception specification with instantiation-dependent types
+//
+// <ref-qualifier> ::= R                   # & ref-qualifier
+// <ref-qualifier> ::= O                   # && ref-qualifier
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseFunctionType() {
+  Qualifiers CVQuals = parseCVQualifiers();
+
+  Node *ExceptionSpec = nullptr;
+  if (consumeIf("Do")) {
+    ExceptionSpec = make<NameType>("noexcept");
+    if (!ExceptionSpec)
+      return nullptr;
+  } else if (consumeIf("DO")) {
+    Node *E = getDerived().parseExpr();
+    if (E == nullptr || !consumeIf('E'))
+      return nullptr;
+    ExceptionSpec = make<NoexceptSpec>(E);
+    if (!ExceptionSpec)
+      return nullptr;
+  } else if (consumeIf("Dw")) {
+    size_t SpecsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *T = getDerived().parseType();
+      if (T == nullptr)
+        return nullptr;
+      Names.push_back(T);
+    }
+    ExceptionSpec =
+      make<DynamicExceptionSpec>(popTrailingNodeArray(SpecsBegin));
+    if (!ExceptionSpec)
+      return nullptr;
+  }
+
+  consumeIf("Dx"); // transaction safe
+
+  if (!consumeIf('F'))
+    return nullptr;
+  consumeIf('Y'); // extern "C"
+  Node *ReturnType = getDerived().parseType();
+  if (ReturnType == nullptr)
+    return nullptr;
+
+  FunctionRefQual ReferenceQualifier = FrefQualNone;
+  size_t ParamsBegin = Names.size();
+  while (true) {
+    if (consumeIf('E'))
+      break;
+    if (consumeIf('v'))
+      continue;
+    if (consumeIf("RE")) {
+      ReferenceQualifier = FrefQualLValue;
+      break;
+    }
+    if (consumeIf("OE")) {
+      ReferenceQualifier = FrefQualRValue;
+      break;
+    }
+    Node *T = getDerived().parseType();
+    if (T == nullptr)
+      return nullptr;
+    Names.push_back(T);
+  }
+
+  NodeArray Params = popTrailingNodeArray(ParamsBegin);
+  return make<FunctionType>(ReturnType, Params, CVQuals,
+                            ReferenceQualifier, ExceptionSpec);
+}
+
+// extension:
+// <vector-type>           ::= Dv <positive dimension number> _ <extended element type>
+//                         ::= Dv [<dimension expression>] _ <element type>
+// <extended element type> ::= <element type>
+//                         ::= p # AltiVec vector pixel
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseVectorType() {
+  if (!consumeIf("Dv"))
+    return nullptr;
+  if (look() >= '1' && look() <= '9') {
+    StringView DimensionNumber = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    if (consumeIf('p'))
+      return make<PixelVectorType>(DimensionNumber);
+    Node *ElemType = getDerived().parseType();
+    if (ElemType == nullptr)
+      return nullptr;
+    return make<VectorType>(ElemType, DimensionNumber);
+  }
+
+  if (!consumeIf('_')) {
+    Node *DimExpr = getDerived().parseExpr();
+    if (!DimExpr)
+      return nullptr;
+    if (!consumeIf('_'))
+      return nullptr;
+    Node *ElemType = getDerived().parseType();
+    if (!ElemType)
+      return nullptr;
+    return make<VectorType>(ElemType, DimExpr);
+  }
+  Node *ElemType = getDerived().parseType();
+  if (!ElemType)
+    return nullptr;
+  return make<VectorType>(ElemType, StringView());
+}
+
+// <decltype>  ::= Dt <expression> E  # decltype of an id-expression or class member access (C++0x)
+//             ::= DT <expression> E  # decltype of an expression (C++0x)
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseDecltype() {
+  if (!consumeIf('D'))
+    return nullptr;
+  if (!consumeIf('t') && !consumeIf('T'))
+    return nullptr;
+  Node *E = getDerived().parseExpr();
+  if (E == nullptr)
+    return nullptr;
+  if (!consumeIf('E'))
+    return nullptr;
+  return make<EnclosingExpr>("decltype(", E, ")");
+}
+
+// <array-type> ::= A <positive dimension number> _ <element type>
+//              ::= A [<dimension expression>] _ <element type>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseArrayType() {
+  if (!consumeIf('A'))
+    return nullptr;
+
+  NodeOrString Dimension;
+
+  if (std::isdigit(look())) {
+    Dimension = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+  } else if (!consumeIf('_')) {
+    Node *DimExpr = getDerived().parseExpr();
+    if (DimExpr == nullptr)
+      return nullptr;
+    if (!consumeIf('_'))
+      return nullptr;
+    Dimension = DimExpr;
+  }
+
+  Node *Ty = getDerived().parseType();
+  if (Ty == nullptr)
+    return nullptr;
+  return make<ArrayType>(Ty, Dimension);
+}
+
+// <pointer-to-member-type> ::= M <class type> <member type>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parsePointerToMemberType() {
+  if (!consumeIf('M'))
+    return nullptr;
+  Node *ClassType = getDerived().parseType();
+  if (ClassType == nullptr)
+    return nullptr;
+  Node *MemberType = getDerived().parseType();
+  if (MemberType == nullptr)
+    return nullptr;
+  return make<PointerToMemberType>(ClassType, MemberType);
+}
+
+// <class-enum-type> ::= <name>     # non-dependent type name, dependent type name, or dependent typename-specifier
+//                   ::= Ts <name>  # dependent elaborated type specifier using 'struct' or 'class'
+//                   ::= Tu <name>  # dependent elaborated type specifier using 'union'
+//                   ::= Te <name>  # dependent elaborated type specifier using 'enum'
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseClassEnumType() {
+  StringView ElabSpef;
+  if (consumeIf("Ts"))
+    ElabSpef = "struct";
+  else if (consumeIf("Tu"))
+    ElabSpef = "union";
+  else if (consumeIf("Te"))
+    ElabSpef = "enum";
+
+  Node *Name = getDerived().parseName();
+  if (Name == nullptr)
+    return nullptr;
+
+  if (!ElabSpef.empty())
+    return make<ElaboratedTypeSpefType>(ElabSpef, Name);
+
+  return Name;
+}
+
+// <qualified-type>     ::= <qualifiers> <type>
+// <qualifiers> ::= <extended-qualifier>* <CV-qualifiers>
+// <extended-qualifier> ::= U <source-name> [<template-args>] # vendor extended type qualifier
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseQualifiedType() {
+  if (consumeIf('U')) {
+    StringView Qual = parseBareSourceName();
+    if (Qual.empty())
+      return nullptr;
+
+    // FIXME parse the optional <template-args> here!
+
+    // extension            ::= U <objc-name> <objc-type>  # objc-type<identifier>
+    if (Qual.startsWith("objcproto")) {
+      StringView ProtoSourceName = Qual.dropFront(std::strlen("objcproto"));
+      StringView Proto;
+      {
+        SwapAndRestore<const char *> SaveFirst(First, ProtoSourceName.begin()),
+                                     SaveLast(Last, ProtoSourceName.end());
+        Proto = parseBareSourceName();
+      }
+      if (Proto.empty())
+        return nullptr;
+      Node *Child = getDerived().parseQualifiedType();
+      if (Child == nullptr)
+        return nullptr;
+      return make<ObjCProtoName>(Child, Proto);
+    }
+
+    Node *Child = getDerived().parseQualifiedType();
+    if (Child == nullptr)
+      return nullptr;
+    return make<VendorExtQualType>(Child, Qual);
+  }
+
+  Qualifiers Quals = parseCVQualifiers();
+  Node *Ty = getDerived().parseType();
+  if (Ty == nullptr)
+    return nullptr;
+  if (Quals != QualNone)
+    Ty = make<QualType>(Ty, Quals);
+  return Ty;
+}
+
+// <type>      ::= <builtin-type>
+//             ::= <qualified-type>
+//             ::= <function-type>
+//             ::= <class-enum-type>
+//             ::= <array-type>
+//             ::= <pointer-to-member-type>
+//             ::= <template-param>
+//             ::= <template-template-param> <template-args>
+//             ::= <decltype>
+//             ::= P <type>        # pointer
+//             ::= R <type>        # l-value reference
+//             ::= O <type>        # r-value reference (C++11)
+//             ::= C <type>        # complex pair (C99)
+//             ::= G <type>        # imaginary (C99)
+//             ::= <substitution>  # See Compression below
+// extension   ::= U <objc-name> <objc-type>  # objc-type<identifier>
+// extension   ::= <vector-type> # <vector-type> starts with Dv
+//
+// <objc-name> ::= <k0 number> objcproto <k1 number> <identifier>  # k0 = 9 + <number of digits in k1> + k1
+// <objc-type> ::= <source-name>  # PU<11+>objcproto 11objc_object<source-name> 11objc_object -> id<source-name>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseType() {
+  Node *Result = nullptr;
+
+  switch (look()) {
+  //             ::= <qualified-type>
+  case 'r':
+  case 'V':
+  case 'K': {
+    unsigned AfterQuals = 0;
+    if (look(AfterQuals) == 'r') ++AfterQuals;
+    if (look(AfterQuals) == 'V') ++AfterQuals;
+    if (look(AfterQuals) == 'K') ++AfterQuals;
+
+    if (look(AfterQuals) == 'F' ||
+        (look(AfterQuals) == 'D' &&
+         (look(AfterQuals + 1) == 'o' || look(AfterQuals + 1) == 'O' ||
+          look(AfterQuals + 1) == 'w' || look(AfterQuals + 1) == 'x'))) {
+      Result = getDerived().parseFunctionType();
+      break;
+    }
+    DEMANGLE_FALLTHROUGH;
+  }
+  case 'U': {
+    Result = getDerived().parseQualifiedType();
+    break;
+  }
+  // <builtin-type> ::= v    # void
+  case 'v':
+    ++First;
+    return make<NameType>("void");
+  //                ::= w    # wchar_t
+  case 'w':
+    ++First;
+    return make<NameType>("wchar_t");
+  //                ::= b    # bool
+  case 'b':
+    ++First;
+    return make<NameType>("bool");
+  //                ::= c    # char
+  case 'c':
+    ++First;
+    return make<NameType>("char");
+  //                ::= a    # signed char
+  case 'a':
+    ++First;
+    return make<NameType>("signed char");
+  //                ::= h    # unsigned char
+  case 'h':
+    ++First;
+    return make<NameType>("unsigned char");
+  //                ::= s    # short
+  case 's':
+    ++First;
+    return make<NameType>("short");
+  //                ::= t    # unsigned short
+  case 't':
+    ++First;
+    return make<NameType>("unsigned short");
+  //                ::= i    # int
+  case 'i':
+    ++First;
+    return make<NameType>("int");
+  //                ::= j    # unsigned int
+  case 'j':
+    ++First;
+    return make<NameType>("unsigned int");
+  //                ::= l    # long
+  case 'l':
+    ++First;
+    return make<NameType>("long");
+  //                ::= m    # unsigned long
+  case 'm':
+    ++First;
+    return make<NameType>("unsigned long");
+  //                ::= x    # long long, __int64
+  case 'x':
+    ++First;
+    return make<NameType>("long long");
+  //                ::= y    # unsigned long long, __int64
+  case 'y':
+    ++First;
+    return make<NameType>("unsigned long long");
+  //                ::= n    # __int128
+  case 'n':
+    ++First;
+    return make<NameType>("__int128");
+  //                ::= o    # unsigned __int128
+  case 'o':
+    ++First;
+    return make<NameType>("unsigned __int128");
+  //                ::= f    # float
+  case 'f':
+    ++First;
+    return make<NameType>("float");
+  //                ::= d    # double
+  case 'd':
+    ++First;
+    return make<NameType>("double");
+  //                ::= e    # long double, __float80
+  case 'e':
+    ++First;
+    return make<NameType>("long double");
+  //                ::= g    # __float128
+  case 'g':
+    ++First;
+    return make<NameType>("__float128");
+  //                ::= z    # ellipsis
+  case 'z':
+    ++First;
+    return make<NameType>("...");
+
+  // <builtin-type> ::= u <source-name>    # vendor extended type
+  case 'u': {
+    ++First;
+    StringView Res = parseBareSourceName();
+    if (Res.empty())
+      return nullptr;
+    // Typically, <builtin-type>s are not considered substitution candidates,
+    // but the exception to that exception is vendor extended types (Itanium C++
+    // ABI 5.9.1).
+    Result = make<NameType>(Res);
+    break;
+  }
+  case 'D':
+    switch (look(1)) {
+    //                ::= Dd   # IEEE 754r decimal floating point (64 bits)
+    case 'd':
+      First += 2;
+      return make<NameType>("decimal64");
+    //                ::= De   # IEEE 754r decimal floating point (128 bits)
+    case 'e':
+      First += 2;
+      return make<NameType>("decimal128");
+    //                ::= Df   # IEEE 754r decimal floating point (32 bits)
+    case 'f':
+      First += 2;
+      return make<NameType>("decimal32");
+    //                ::= Dh   # IEEE 754r half-precision floating point (16 bits)
+    case 'h':
+      First += 2;
+      return make<NameType>("decimal16");
+    //                ::= Di   # char32_t
+    case 'i':
+      First += 2;
+      return make<NameType>("char32_t");
+    //                ::= Ds   # char16_t
+    case 's':
+      First += 2;
+      return make<NameType>("char16_t");
+    //                ::= Du   # char8_t (C++2a, not yet in the Itanium spec)
+    case 'u':
+      First += 2;
+      return make<NameType>("char8_t");
+    //                ::= Da   # auto (in dependent new-expressions)
+    case 'a':
+      First += 2;
+      return make<NameType>("auto");
+    //                ::= Dc   # decltype(auto)
+    case 'c':
+      First += 2;
+      return make<NameType>("decltype(auto)");
+    //                ::= Dn   # std::nullptr_t (i.e., decltype(nullptr))
+    case 'n':
+      First += 2;
+      return make<NameType>("std::nullptr_t");
+
+    //             ::= <decltype>
+    case 't':
+    case 'T': {
+      Result = getDerived().parseDecltype();
+      break;
+    }
+    // extension   ::= <vector-type> # <vector-type> starts with Dv
+    case 'v': {
+      Result = getDerived().parseVectorType();
+      break;
+    }
+    //           ::= Dp <type>       # pack expansion (C++0x)
+    case 'p': {
+      First += 2;
+      Node *Child = getDerived().parseType();
+      if (!Child)
+        return nullptr;
+      Result = make<ParameterPackExpansion>(Child);
+      break;
+    }
+    // Exception specifier on a function type.
+    case 'o':
+    case 'O':
+    case 'w':
+    // Transaction safe function type.
+    case 'x':
+      Result = getDerived().parseFunctionType();
+      break;
+    }
+    break;
+  //             ::= <function-type>
+  case 'F': {
+    Result = getDerived().parseFunctionType();
+    break;
+  }
+  //             ::= <array-type>
+  case 'A': {
+    Result = getDerived().parseArrayType();
+    break;
+  }
+  //             ::= <pointer-to-member-type>
+  case 'M': {
+    Result = getDerived().parsePointerToMemberType();
+    break;
+  }
+  //             ::= <template-param>
+  case 'T': {
+    // This could be an elaborate type specifier on a <class-enum-type>.
+    if (look(1) == 's' || look(1) == 'u' || look(1) == 'e') {
+      Result = getDerived().parseClassEnumType();
+      break;
+    }
+
+    Result = getDerived().parseTemplateParam();
+    if (Result == nullptr)
+      return nullptr;
+
+    // Result could be either of:
+    //   <type>        ::= <template-param>
+    //   <type>        ::= <template-template-param> <template-args>
+    //
+    //   <template-template-param> ::= <template-param>
+    //                             ::= <substitution>
+    //
+    // If this is followed by some <template-args>, and we're permitted to
+    // parse them, take the second production.
+
+    if (TryToParseTemplateArgs && look() == 'I') {
+      Node *TA = getDerived().parseTemplateArgs();
+      if (TA == nullptr)
+        return nullptr;
+      Result = make<NameWithTemplateArgs>(Result, TA);
+    }
+    break;
+  }
+  //             ::= P <type>        # pointer
+  case 'P': {
+    ++First;
+    Node *Ptr = getDerived().parseType();
+    if (Ptr == nullptr)
+      return nullptr;
+    Result = make<PointerType>(Ptr);
+    break;
+  }
+  //             ::= R <type>        # l-value reference
+  case 'R': {
+    ++First;
+    Node *Ref = getDerived().parseType();
+    if (Ref == nullptr)
+      return nullptr;
+    Result = make<ReferenceType>(Ref, ReferenceKind::LValue);
+    break;
+  }
+  //             ::= O <type>        # r-value reference (C++11)
+  case 'O': {
+    ++First;
+    Node *Ref = getDerived().parseType();
+    if (Ref == nullptr)
+      return nullptr;
+    Result = make<ReferenceType>(Ref, ReferenceKind::RValue);
+    break;
+  }
+  //             ::= C <type>        # complex pair (C99)
+  case 'C': {
+    ++First;
+    Node *P = getDerived().parseType();
+    if (P == nullptr)
+      return nullptr;
+    Result = make<PostfixQualifiedType>(P, " complex");
+    break;
+  }
+  //             ::= G <type>        # imaginary (C99)
+  case 'G': {
+    ++First;
+    Node *P = getDerived().parseType();
+    if (P == nullptr)
+      return P;
+    Result = make<PostfixQualifiedType>(P, " imaginary");
+    break;
+  }
+  //             ::= <substitution>  # See Compression below
+  case 'S': {
+    if (look(1) && look(1) != 't') {
+      Node *Sub = getDerived().parseSubstitution();
+      if (Sub == nullptr)
+        return nullptr;
+
+      // Sub could be either of:
+      //   <type>        ::= <substitution>
+      //   <type>        ::= <template-template-param> <template-args>
+      //
+      //   <template-template-param> ::= <template-param>
+      //                             ::= <substitution>
+      //
+      // If this is followed by some <template-args>, and we're permitted to
+      // parse them, take the second production.
+
+      if (TryToParseTemplateArgs && look() == 'I') {
+        Node *TA = getDerived().parseTemplateArgs();
+        if (TA == nullptr)
+          return nullptr;
+        Result = make<NameWithTemplateArgs>(Sub, TA);
+        break;
+      }
+
+      // If all we parsed was a substitution, don't re-insert into the
+      // substitution table.
+      return Sub;
+    }
+    DEMANGLE_FALLTHROUGH;
+  }
+  //        ::= <class-enum-type>
+  default: {
+    Result = getDerived().parseClassEnumType();
+    break;
+  }
+  }
+
+  // If we parsed a type, insert it into the substitution table. Note that all
+  // <builtin-type>s and <substitution>s have already bailed out, because they
+  // don't get substitutions.
+  if (Result != nullptr)
+    Subs.push_back(Result);
+  return Result;
+}
+
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parsePrefixExpr(StringView Kind) {
+  Node *E = getDerived().parseExpr();
+  if (E == nullptr)
+    return nullptr;
+  return make<PrefixExpr>(Kind, E);
+}
+
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseBinaryExpr(StringView Kind) {
+  Node *LHS = getDerived().parseExpr();
+  if (LHS == nullptr)
+    return nullptr;
+  Node *RHS = getDerived().parseExpr();
+  if (RHS == nullptr)
+    return nullptr;
+  return make<BinaryExpr>(LHS, Kind, RHS);
+}
+
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseIntegerLiteral(StringView Lit) {
+  StringView Tmp = parseNumber(true);
+  if (!Tmp.empty() && consumeIf('E'))
+    return make<IntegerLiteral>(Lit, Tmp);
+  return nullptr;
+}
+
+// <CV-Qualifiers> ::= [r] [V] [K]
+template <typename Alloc, typename Derived>
+Qualifiers AbstractManglingParser<Alloc, Derived>::parseCVQualifiers() {
+  Qualifiers CVR = QualNone;
+  if (consumeIf('r'))
+    CVR |= QualRestrict;
+  if (consumeIf('V'))
+    CVR |= QualVolatile;
+  if (consumeIf('K'))
+    CVR |= QualConst;
+  return CVR;
+}
+
+// <function-param> ::= fp <top-level CV-Qualifiers> _                                     # L == 0, first parameter
+//                  ::= fp <top-level CV-Qualifiers> <parameter-2 non-negative number> _   # L == 0, second and later parameters
+//                  ::= fL <L-1 non-negative number> p <top-level CV-Qualifiers> _         # L > 0, first parameter
+//                  ::= fL <L-1 non-negative number> p <top-level CV-Qualifiers> <parameter-2 non-negative number> _   # L > 0, second and later parameters
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseFunctionParam() {
+  if (consumeIf("fp")) {
+    parseCVQualifiers();
+    StringView Num = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    return make<FunctionParam>(Num);
+  }
+  if (consumeIf("fL")) {
+    if (parseNumber().empty())
+      return nullptr;
+    if (!consumeIf('p'))
+      return nullptr;
+    parseCVQualifiers();
+    StringView Num = parseNumber();
+    if (!consumeIf('_'))
+      return nullptr;
+    return make<FunctionParam>(Num);
+  }
+  return nullptr;
+}
+
+// [gs] nw <expression>* _ <type> E                     # new (expr-list) type
+// [gs] nw <expression>* _ <type> <initializer>         # new (expr-list) type (init)
+// [gs] na <expression>* _ <type> E                     # new[] (expr-list) type
+// [gs] na <expression>* _ <type> <initializer>         # new[] (expr-list) type (init)
+// <initializer> ::= pi <expression>* E                 # parenthesized initialization
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseNewExpr() {
+  bool Global = consumeIf("gs");
+  bool IsArray = look(1) == 'a';
+  if (!consumeIf("nw") && !consumeIf("na"))
+    return nullptr;
+  size_t Exprs = Names.size();
+  while (!consumeIf('_')) {
+    Node *Ex = getDerived().parseExpr();
+    if (Ex == nullptr)
+      return nullptr;
+    Names.push_back(Ex);
+  }
+  NodeArray ExprList = popTrailingNodeArray(Exprs);
+  Node *Ty = getDerived().parseType();
+  if (Ty == nullptr)
+    return Ty;
+  if (consumeIf("pi")) {
+    size_t InitsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *Init = getDerived().parseExpr();
+      if (Init == nullptr)
+        return Init;
+      Names.push_back(Init);
+    }
+    NodeArray Inits = popTrailingNodeArray(InitsBegin);
+    return make<NewExpr>(ExprList, Ty, Inits, Global, IsArray);
+  } else if (!consumeIf('E'))
+    return nullptr;
+  return make<NewExpr>(ExprList, Ty, NodeArray(), Global, IsArray);
+}
+
+// cv <type> <expression>                               # conversion with one argument
+// cv <type> _ <expression>* E                          # conversion with a different number of arguments
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseConversionExpr() {
+  if (!consumeIf("cv"))
+    return nullptr;
+  Node *Ty;
+  {
+    SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+    Ty = getDerived().parseType();
+  }
+
+  if (Ty == nullptr)
+    return nullptr;
+
+  if (consumeIf('_')) {
+    size_t ExprsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *E = getDerived().parseExpr();
+      if (E == nullptr)
+        return E;
+      Names.push_back(E);
+    }
+    NodeArray Exprs = popTrailingNodeArray(ExprsBegin);
+    return make<ConversionExpr>(Ty, Exprs);
+  }
+
+  Node *E[1] = {getDerived().parseExpr()};
+  if (E[0] == nullptr)
+    return nullptr;
+  return make<ConversionExpr>(Ty, makeNodeArray(E, E + 1));
+}
+
+// <expr-primary> ::= L <type> <value number> E                          # integer literal
+//                ::= L <type> <value float> E                           # floating literal
+//                ::= L <string type> E                                  # string literal
+//                ::= L <nullptr type> E                                 # nullptr literal (i.e., "LDnE")
+//                ::= L <lambda type> E                                  # lambda expression
+// FIXME:         ::= L <type> <real-part float> _ <imag-part float> E   # complex floating point literal (C 2000)
+//                ::= L <mangled-name> E                                 # external name
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseExprPrimary() {
+  if (!consumeIf('L'))
+    return nullptr;
+  switch (look()) {
+  case 'w':
+    ++First;
+    return getDerived().parseIntegerLiteral("wchar_t");
+  case 'b':
+    if (consumeIf("b0E"))
+      return make<BoolExpr>(0);
+    if (consumeIf("b1E"))
+      return make<BoolExpr>(1);
+    return nullptr;
+  case 'c':
+    ++First;
+    return getDerived().parseIntegerLiteral("char");
+  case 'a':
+    ++First;
+    return getDerived().parseIntegerLiteral("signed char");
+  case 'h':
+    ++First;
+    return getDerived().parseIntegerLiteral("unsigned char");
+  case 's':
+    ++First;
+    return getDerived().parseIntegerLiteral("short");
+  case 't':
+    ++First;
+    return getDerived().parseIntegerLiteral("unsigned short");
+  case 'i':
+    ++First;
+    return getDerived().parseIntegerLiteral("");
+  case 'j':
+    ++First;
+    return getDerived().parseIntegerLiteral("u");
+  case 'l':
+    ++First;
+    return getDerived().parseIntegerLiteral("l");
+  case 'm':
+    ++First;
+    return getDerived().parseIntegerLiteral("ul");
+  case 'x':
+    ++First;
+    return getDerived().parseIntegerLiteral("ll");
+  case 'y':
+    ++First;
+    return getDerived().parseIntegerLiteral("ull");
+  case 'n':
+    ++First;
+    return getDerived().parseIntegerLiteral("__int128");
+  case 'o':
+    ++First;
+    return getDerived().parseIntegerLiteral("unsigned __int128");
+  case 'f':
+    ++First;
+    return getDerived().template parseFloatingLiteral<float>();
+  case 'd':
+    ++First;
+    return getDerived().template parseFloatingLiteral<double>();
+  case 'e':
+    ++First;
+    return getDerived().template parseFloatingLiteral<long double>();
+  case '_':
+    if (consumeIf("_Z")) {
+      Node *R = getDerived().parseEncoding();
+      if (R != nullptr && consumeIf('E'))
+        return R;
+    }
+    return nullptr;
+  case 'A': {
+    Node *T = getDerived().parseType();
+    if (T == nullptr)
+      return nullptr;
+    // FIXME: We need to include the string contents in the mangling.
+    if (consumeIf('E'))
+      return make<StringLiteral>(T);
+    return nullptr;
+  }
+  case 'D':
+    if (consumeIf("DnE"))
+      return make<NameType>("nullptr");
+    return nullptr;
+  case 'T':
+    // Invalid mangled name per
+    //   http://sourcerytools.com/pipermail/cxx-abi-dev/2011-August/002422.html
+    return nullptr;
+  case 'U': {
+    // FIXME: Should we support LUb... for block literals?
+    if (look(1) != 'l')
+      return nullptr;
+    Node *T = parseUnnamedTypeName(nullptr);
+    if (!T || !consumeIf('E'))
+      return nullptr;
+    return make<LambdaExpr>(T);
+  }
+  default: {
+    // might be named type
+    Node *T = getDerived().parseType();
+    if (T == nullptr)
+      return nullptr;
+    StringView N = parseNumber();
+    if (N.empty())
+      return nullptr;
+    if (!consumeIf('E'))
+      return nullptr;
+    return make<IntegerCastExpr>(T, N);
+  }
+  }
+}
+
+// <braced-expression> ::= <expression>
+//                     ::= di <field source-name> <braced-expression>    # .name = expr
+//                     ::= dx <index expression> <braced-expression>     # [expr] = expr
+//                     ::= dX <range begin expression> <range end expression> <braced-expression>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseBracedExpr() {
+  if (look() == 'd') {
+    switch (look(1)) {
+    case 'i': {
+      First += 2;
+      Node *Field = getDerived().parseSourceName(/*NameState=*/nullptr);
+      if (Field == nullptr)
+        return nullptr;
+      Node *Init = getDerived().parseBracedExpr();
+      if (Init == nullptr)
+        return nullptr;
+      return make<BracedExpr>(Field, Init, /*isArray=*/false);
+    }
+    case 'x': {
+      First += 2;
+      Node *Index = getDerived().parseExpr();
+      if (Index == nullptr)
+        return nullptr;
+      Node *Init = getDerived().parseBracedExpr();
+      if (Init == nullptr)
+        return nullptr;
+      return make<BracedExpr>(Index, Init, /*isArray=*/true);
+    }
+    case 'X': {
+      First += 2;
+      Node *RangeBegin = getDerived().parseExpr();
+      if (RangeBegin == nullptr)
+        return nullptr;
+      Node *RangeEnd = getDerived().parseExpr();
+      if (RangeEnd == nullptr)
+        return nullptr;
+      Node *Init = getDerived().parseBracedExpr();
+      if (Init == nullptr)
+        return nullptr;
+      return make<BracedRangeExpr>(RangeBegin, RangeEnd, Init);
+    }
+    }
+  }
+  return getDerived().parseExpr();
+}
+
+// (not yet in the spec)
+// <fold-expr> ::= fL <binary-operator-name> <expression> <expression>
+//             ::= fR <binary-operator-name> <expression> <expression>
+//             ::= fl <binary-operator-name> <expression>
+//             ::= fr <binary-operator-name> <expression>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseFoldExpr() {
+  if (!consumeIf('f'))
+    return nullptr;
+
+  char FoldKind = look();
+  bool IsLeftFold, HasInitializer;
+  HasInitializer = FoldKind == 'L' || FoldKind == 'R';
+  if (FoldKind == 'l' || FoldKind == 'L')
+    IsLeftFold = true;
+  else if (FoldKind == 'r' || FoldKind == 'R')
+    IsLeftFold = false;
+  else
+    return nullptr;
+  ++First;
+
+  // FIXME: This map is duplicated in parseOperatorName and parseExpr.
+  StringView OperatorName;
+  if      (consumeIf("aa")) OperatorName = "&&";
+  else if (consumeIf("an")) OperatorName = "&";
+  else if (consumeIf("aN")) OperatorName = "&=";
+  else if (consumeIf("aS")) OperatorName = "=";
+  else if (consumeIf("cm")) OperatorName = ",";
+  else if (consumeIf("ds")) OperatorName = ".*";
+  else if (consumeIf("dv")) OperatorName = "/";
+  else if (consumeIf("dV")) OperatorName = "/=";
+  else if (consumeIf("eo")) OperatorName = "^";
+  else if (consumeIf("eO")) OperatorName = "^=";
+  else if (consumeIf("eq")) OperatorName = "==";
+  else if (consumeIf("ge")) OperatorName = ">=";
+  else if (consumeIf("gt")) OperatorName = ">";
+  else if (consumeIf("le")) OperatorName = "<=";
+  else if (consumeIf("ls")) OperatorName = "<<";
+  else if (consumeIf("lS")) OperatorName = "<<=";
+  else if (consumeIf("lt")) OperatorName = "<";
+  else if (consumeIf("mi")) OperatorName = "-";
+  else if (consumeIf("mI")) OperatorName = "-=";
+  else if (consumeIf("ml")) OperatorName = "*";
+  else if (consumeIf("mL")) OperatorName = "*=";
+  else if (consumeIf("ne")) OperatorName = "!=";
+  else if (consumeIf("oo")) OperatorName = "||";
+  else if (consumeIf("or")) OperatorName = "|";
+  else if (consumeIf("oR")) OperatorName = "|=";
+  else if (consumeIf("pl")) OperatorName = "+";
+  else if (consumeIf("pL")) OperatorName = "+=";
+  else if (consumeIf("rm")) OperatorName = "%";
+  else if (consumeIf("rM")) OperatorName = "%=";
+  else if (consumeIf("rs")) OperatorName = ">>";
+  else if (consumeIf("rS")) OperatorName = ">>=";
+  else return nullptr;
+
+  Node *Pack = getDerived().parseExpr(), *Init = nullptr;
+  if (Pack == nullptr)
+    return nullptr;
+  if (HasInitializer) {
+    Init = getDerived().parseExpr();
+    if (Init == nullptr)
+      return nullptr;
+  }
+
+  if (IsLeftFold && Init)
+    std::swap(Pack, Init);
+
+  return make<FoldExpr>(IsLeftFold, OperatorName, Pack, Init);
+}
+
+// <expression> ::= <unary operator-name> <expression>
+//              ::= <binary operator-name> <expression> <expression>
+//              ::= <ternary operator-name> <expression> <expression> <expression>
+//              ::= cl <expression>+ E                                   # call
+//              ::= cv <type> <expression>                               # conversion with one argument
+//              ::= cv <type> _ <expression>* E                          # conversion with a different number of arguments
+//              ::= [gs] nw <expression>* _ <type> E                     # new (expr-list) type
+//              ::= [gs] nw <expression>* _ <type> <initializer>         # new (expr-list) type (init)
+//              ::= [gs] na <expression>* _ <type> E                     # new[] (expr-list) type
+//              ::= [gs] na <expression>* _ <type> <initializer>         # new[] (expr-list) type (init)
+//              ::= [gs] dl <expression>                                 # delete expression
+//              ::= [gs] da <expression>                                 # delete[] expression
+//              ::= pp_ <expression>                                     # prefix ++
+//              ::= mm_ <expression>                                     # prefix --
+//              ::= ti <type>                                            # typeid (type)
+//              ::= te <expression>                                      # typeid (expression)
+//              ::= dc <type> <expression>                               # dynamic_cast<type> (expression)
+//              ::= sc <type> <expression>                               # static_cast<type> (expression)
+//              ::= cc <type> <expression>                               # const_cast<type> (expression)
+//              ::= rc <type> <expression>                               # reinterpret_cast<type> (expression)
+//              ::= st <type>                                            # sizeof (a type)
+//              ::= sz <expression>                                      # sizeof (an expression)
+//              ::= at <type>                                            # alignof (a type)
+//              ::= az <expression>                                      # alignof (an expression)
+//              ::= nx <expression>                                      # noexcept (expression)
+//              ::= <template-param>
+//              ::= <function-param>
+//              ::= dt <expression> <unresolved-name>                    # expr.name
+//              ::= pt <expression> <unresolved-name>                    # expr->name
+//              ::= ds <expression> <expression>                         # expr.*expr
+//              ::= sZ <template-param>                                  # size of a parameter pack
+//              ::= sZ <function-param>                                  # size of a function parameter pack
+//              ::= sP <template-arg>* E                                 # sizeof...(T), size of a captured template parameter pack from an alias template
+//              ::= sp <expression>                                      # pack expansion
+//              ::= tw <expression>                                      # throw expression
+//              ::= tr                                                   # throw with no operand (rethrow)
+//              ::= <unresolved-name>                                    # f(p), N::f(p), ::f(p),
+//                                                                       # freestanding dependent name (e.g., T::x),
+//                                                                       # objectless nonstatic member reference
+//              ::= fL <binary-operator-name> <expression> <expression>
+//              ::= fR <binary-operator-name> <expression> <expression>
+//              ::= fl <binary-operator-name> <expression>
+//              ::= fr <binary-operator-name> <expression>
+//              ::= <expr-primary>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
+  bool Global = consumeIf("gs");
+  if (numLeft() < 2)
+    return nullptr;
+
+  switch (*First) {
+  case 'L':
+    return getDerived().parseExprPrimary();
+  case 'T':
+    return getDerived().parseTemplateParam();
+  case 'f': {
+    // Disambiguate a fold expression from a <function-param>.
+    if (look(1) == 'p' || (look(1) == 'L' && std::isdigit(look(2))))
+      return getDerived().parseFunctionParam();
+    return getDerived().parseFoldExpr();
+  }
+  case 'a':
+    switch (First[1]) {
+    case 'a':
+      First += 2;
+      return getDerived().parseBinaryExpr("&&");
+    case 'd':
+      First += 2;
+      return getDerived().parsePrefixExpr("&");
+    case 'n':
+      First += 2;
+      return getDerived().parseBinaryExpr("&");
+    case 'N':
+      First += 2;
+      return getDerived().parseBinaryExpr("&=");
+    case 'S':
+      First += 2;
+      return getDerived().parseBinaryExpr("=");
+    case 't': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<EnclosingExpr>("alignof (", Ty, ")");
+    }
+    case 'z': {
+      First += 2;
+      Node *Ty = getDerived().parseExpr();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<EnclosingExpr>("alignof (", Ty, ")");
+    }
+    }
+    return nullptr;
+  case 'c':
+    switch (First[1]) {
+    // cc <type> <expression>                               # const_cast<type>(expression)
+    case 'c': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return Ty;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<CastExpr>("const_cast", Ty, Ex);
+    }
+    // cl <expression>+ E                                   # call
+    case 'l': {
+      First += 2;
+      Node *Callee = getDerived().parseExpr();
+      if (Callee == nullptr)
+        return Callee;
+      size_t ExprsBegin = Names.size();
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseExpr();
+        if (E == nullptr)
+          return E;
+        Names.push_back(E);
+      }
+      return make<CallExpr>(Callee, popTrailingNodeArray(ExprsBegin));
+    }
+    case 'm':
+      First += 2;
+      return getDerived().parseBinaryExpr(",");
+    case 'o':
+      First += 2;
+      return getDerived().parsePrefixExpr("~");
+    case 'v':
+      return getDerived().parseConversionExpr();
+    }
+    return nullptr;
+  case 'd':
+    switch (First[1]) {
+    case 'a': {
+      First += 2;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<DeleteExpr>(Ex, Global, /*is_array=*/true);
+    }
+    case 'c': {
+      First += 2;
+      Node *T = getDerived().parseType();
+      if (T == nullptr)
+        return T;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<CastExpr>("dynamic_cast", T, Ex);
+    }
+    case 'e':
+      First += 2;
+      return getDerived().parsePrefixExpr("*");
+    case 'l': {
+      First += 2;
+      Node *E = getDerived().parseExpr();
+      if (E == nullptr)
+        return E;
+      return make<DeleteExpr>(E, Global, /*is_array=*/false);
+    }
+    case 'n':
+      return getDerived().parseUnresolvedName();
+    case 's': {
+      First += 2;
+      Node *LHS = getDerived().parseExpr();
+      if (LHS == nullptr)
+        return nullptr;
+      Node *RHS = getDerived().parseExpr();
+      if (RHS == nullptr)
+        return nullptr;
+      return make<MemberExpr>(LHS, ".*", RHS);
+    }
+    case 't': {
+      First += 2;
+      Node *LHS = getDerived().parseExpr();
+      if (LHS == nullptr)
+        return LHS;
+      Node *RHS = getDerived().parseExpr();
+      if (RHS == nullptr)
+        return nullptr;
+      return make<MemberExpr>(LHS, ".", RHS);
+    }
+    case 'v':
+      First += 2;
+      return getDerived().parseBinaryExpr("/");
+    case 'V':
+      First += 2;
+      return getDerived().parseBinaryExpr("/=");
+    }
+    return nullptr;
+  case 'e':
+    switch (First[1]) {
+    case 'o':
+      First += 2;
+      return getDerived().parseBinaryExpr("^");
+    case 'O':
+      First += 2;
+      return getDerived().parseBinaryExpr("^=");
+    case 'q':
+      First += 2;
+      return getDerived().parseBinaryExpr("==");
+    }
+    return nullptr;
+  case 'g':
+    switch (First[1]) {
+    case 'e':
+      First += 2;
+      return getDerived().parseBinaryExpr(">=");
+    case 't':
+      First += 2;
+      return getDerived().parseBinaryExpr(">");
+    }
+    return nullptr;
+  case 'i':
+    switch (First[1]) {
+    case 'x': {
+      First += 2;
+      Node *Base = getDerived().parseExpr();
+      if (Base == nullptr)
+        return nullptr;
+      Node *Index = getDerived().parseExpr();
+      if (Index == nullptr)
+        return Index;
+      return make<ArraySubscriptExpr>(Base, Index);
+    }
+    case 'l': {
+      First += 2;
+      size_t InitsBegin = Names.size();
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseBracedExpr();
+        if (E == nullptr)
+          return nullptr;
+        Names.push_back(E);
+      }
+      return make<InitListExpr>(nullptr, popTrailingNodeArray(InitsBegin));
+    }
+    }
+    return nullptr;
+  case 'l':
+    switch (First[1]) {
+    case 'e':
+      First += 2;
+      return getDerived().parseBinaryExpr("<=");
+    case 's':
+      First += 2;
+      return getDerived().parseBinaryExpr("<<");
+    case 'S':
+      First += 2;
+      return getDerived().parseBinaryExpr("<<=");
+    case 't':
+      First += 2;
+      return getDerived().parseBinaryExpr("<");
+    }
+    return nullptr;
+  case 'm':
+    switch (First[1]) {
+    case 'i':
+      First += 2;
+      return getDerived().parseBinaryExpr("-");
+    case 'I':
+      First += 2;
+      return getDerived().parseBinaryExpr("-=");
+    case 'l':
+      First += 2;
+      return getDerived().parseBinaryExpr("*");
+    case 'L':
+      First += 2;
+      return getDerived().parseBinaryExpr("*=");
+    case 'm':
+      First += 2;
+      if (consumeIf('_'))
+        return getDerived().parsePrefixExpr("--");
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return nullptr;
+      return make<PostfixExpr>(Ex, "--");
+    }
+    return nullptr;
+  case 'n':
+    switch (First[1]) {
+    case 'a':
+    case 'w':
+      return getDerived().parseNewExpr();
+    case 'e':
+      First += 2;
+      return getDerived().parseBinaryExpr("!=");
+    case 'g':
+      First += 2;
+      return getDerived().parsePrefixExpr("-");
+    case 't':
+      First += 2;
+      return getDerived().parsePrefixExpr("!");
+    case 'x':
+      First += 2;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<EnclosingExpr>("noexcept (", Ex, ")");
+    }
+    return nullptr;
+  case 'o':
+    switch (First[1]) {
+    case 'n':
+      return getDerived().parseUnresolvedName();
+    case 'o':
+      First += 2;
+      return getDerived().parseBinaryExpr("||");
+    case 'r':
+      First += 2;
+      return getDerived().parseBinaryExpr("|");
+    case 'R':
+      First += 2;
+      return getDerived().parseBinaryExpr("|=");
+    }
+    return nullptr;
+  case 'p':
+    switch (First[1]) {
+    case 'm':
+      First += 2;
+      return getDerived().parseBinaryExpr("->*");
+    case 'l':
+      First += 2;
+      return getDerived().parseBinaryExpr("+");
+    case 'L':
+      First += 2;
+      return getDerived().parseBinaryExpr("+=");
+    case 'p': {
+      First += 2;
+      if (consumeIf('_'))
+        return getDerived().parsePrefixExpr("++");
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<PostfixExpr>(Ex, "++");
+    }
+    case 's':
+      First += 2;
+      return getDerived().parsePrefixExpr("+");
+    case 't': {
+      First += 2;
+      Node *L = getDerived().parseExpr();
+      if (L == nullptr)
+        return nullptr;
+      Node *R = getDerived().parseExpr();
+      if (R == nullptr)
+        return nullptr;
+      return make<MemberExpr>(L, "->", R);
+    }
+    }
+    return nullptr;
+  case 'q':
+    if (First[1] == 'u') {
+      First += 2;
+      Node *Cond = getDerived().parseExpr();
+      if (Cond == nullptr)
+        return nullptr;
+      Node *LHS = getDerived().parseExpr();
+      if (LHS == nullptr)
+        return nullptr;
+      Node *RHS = getDerived().parseExpr();
+      if (RHS == nullptr)
+        return nullptr;
+      return make<ConditionalExpr>(Cond, LHS, RHS);
+    }
+    return nullptr;
+  case 'r':
+    switch (First[1]) {
+    case 'c': {
+      First += 2;
+      Node *T = getDerived().parseType();
+      if (T == nullptr)
+        return T;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<CastExpr>("reinterpret_cast", T, Ex);
+    }
+    case 'm':
+      First += 2;
+      return getDerived().parseBinaryExpr("%");
+    case 'M':
+      First += 2;
+      return getDerived().parseBinaryExpr("%=");
+    case 's':
+      First += 2;
+      return getDerived().parseBinaryExpr(">>");
+    case 'S':
+      First += 2;
+      return getDerived().parseBinaryExpr(">>=");
+    }
+    return nullptr;
+  case 's':
+    switch (First[1]) {
+    case 'c': {
+      First += 2;
+      Node *T = getDerived().parseType();
+      if (T == nullptr)
+        return T;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<CastExpr>("static_cast", T, Ex);
+    }
+    case 'p': {
+      First += 2;
+      Node *Child = getDerived().parseExpr();
+      if (Child == nullptr)
+        return nullptr;
+      return make<ParameterPackExpansion>(Child);
+    }
+    case 'r':
+      return getDerived().parseUnresolvedName();
+    case 't': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return Ty;
+      return make<EnclosingExpr>("sizeof (", Ty, ")");
+    }
+    case 'z': {
+      First += 2;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<EnclosingExpr>("sizeof (", Ex, ")");
+    }
+    case 'Z':
+      First += 2;
+      if (look() == 'T') {
+        Node *R = getDerived().parseTemplateParam();
+        if (R == nullptr)
+          return nullptr;
+        return make<SizeofParamPackExpr>(R);
+      } else if (look() == 'f') {
+        Node *FP = getDerived().parseFunctionParam();
+        if (FP == nullptr)
+          return nullptr;
+        return make<EnclosingExpr>("sizeof... (", FP, ")");
+      }
+      return nullptr;
+    case 'P': {
+      First += 2;
+      size_t ArgsBegin = Names.size();
+      while (!consumeIf('E')) {
+        Node *Arg = getDerived().parseTemplateArg();
+        if (Arg == nullptr)
+          return nullptr;
+        Names.push_back(Arg);
+      }
+      auto *Pack = make<NodeArrayNode>(popTrailingNodeArray(ArgsBegin));
+      if (!Pack)
+        return nullptr;
+      return make<EnclosingExpr>("sizeof... (", Pack, ")");
+    }
+    }
+    return nullptr;
+  case 't':
+    switch (First[1]) {
+    case 'e': {
+      First += 2;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return Ex;
+      return make<EnclosingExpr>("typeid (", Ex, ")");
+    }
+    case 'i': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return Ty;
+      return make<EnclosingExpr>("typeid (", Ty, ")");
+    }
+    case 'l': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      size_t InitsBegin = Names.size();
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseBracedExpr();
+        if (E == nullptr)
+          return nullptr;
+        Names.push_back(E);
+      }
+      return make<InitListExpr>(Ty, popTrailingNodeArray(InitsBegin));
+    }
+    case 'r':
+      First += 2;
+      return make<NameType>("throw");
+    case 'w': {
+      First += 2;
+      Node *Ex = getDerived().parseExpr();
+      if (Ex == nullptr)
+        return nullptr;
+      return make<ThrowExpr>(Ex);
+    }
+    }
+    return nullptr;
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+    return getDerived().parseUnresolvedName();
+  }
+
+  if (consumeIf("u8__uuidoft")) {
+    Node *Ty = getDerived().parseType();
+    if (!Ty)
+      return nullptr;
+    return make<UUIDOfExpr>(Ty);
+  }
+
+  if (consumeIf("u8__uuidofz")) {
+    Node *Ex = getDerived().parseExpr();
+    if (!Ex)
+      return nullptr;
+    return make<UUIDOfExpr>(Ex);
+  }
+
+  return nullptr;
+}
+
+// <call-offset> ::= h <nv-offset> _
+//               ::= v <v-offset> _
+//
+// <nv-offset> ::= <offset number>
+//               # non-virtual base override
+//
+// <v-offset>  ::= <offset number> _ <virtual offset number>
+//               # virtual base override, with vcall offset
+template <typename Alloc, typename Derived>
+bool AbstractManglingParser<Alloc, Derived>::parseCallOffset() {
+  // Just scan through the call offset, we never add this information into the
+  // output.
+  if (consumeIf('h'))
+    return parseNumber(true).empty() || !consumeIf('_');
+  if (consumeIf('v'))
+    return parseNumber(true).empty() || !consumeIf('_') ||
+           parseNumber(true).empty() || !consumeIf('_');
+  return true;
+}
+
+// <special-name> ::= TV <type>    # virtual table
+//                ::= TT <type>    # VTT structure (construction vtable index)
+//                ::= TI <type>    # typeinfo structure
+//                ::= TS <type>    # typeinfo name (null-terminated byte string)
+//                ::= Tc <call-offset> <call-offset> <base encoding>
+//                    # base is the nominal target function of thunk
+//                    # first call-offset is 'this' adjustment
+//                    # second call-offset is result adjustment
+//                ::= T <call-offset> <base encoding>
+//                    # base is the nominal target function of thunk
+//                ::= GV <object name> # Guard variable for one-time initialization
+//                                     # No <type>
+//                ::= TW <object name> # Thread-local wrapper
+//                ::= TH <object name> # Thread-local initialization
+//                ::= GR <object name> _             # First temporary
+//                ::= GR <object name> <seq-id> _    # Subsequent temporaries
+//      extension ::= TC <first type> <number> _ <second type> # construction vtable for second-in-first
+//      extension ::= GR <object name> # reference temporary for object
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseSpecialName() {
+  switch (look()) {
+  case 'T':
+    switch (look(1)) {
+    // TV <type>    # virtual table
+    case 'V': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<SpecialName>("vtable for ", Ty);
+    }
+    // TT <type>    # VTT structure (construction vtable index)
+    case 'T': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<SpecialName>("VTT for ", Ty);
+    }
+    // TI <type>    # typeinfo structure
+    case 'I': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<SpecialName>("typeinfo for ", Ty);
+    }
+    // TS <type>    # typeinfo name (null-terminated byte string)
+    case 'S': {
+      First += 2;
+      Node *Ty = getDerived().parseType();
+      if (Ty == nullptr)
+        return nullptr;
+      return make<SpecialName>("typeinfo name for ", Ty);
+    }
+    // Tc <call-offset> <call-offset> <base encoding>
+    case 'c': {
+      First += 2;
+      if (parseCallOffset() || parseCallOffset())
+        return nullptr;
+      Node *Encoding = getDerived().parseEncoding();
+      if (Encoding == nullptr)
+        return nullptr;
+      return make<SpecialName>("covariant return thunk to ", Encoding);
+    }
+    // extension ::= TC <first type> <number> _ <second type>
+    //               # construction vtable for second-in-first
+    case 'C': {
+      First += 2;
+      Node *FirstType = getDerived().parseType();
+      if (FirstType == nullptr)
+        return nullptr;
+      if (parseNumber(true).empty() || !consumeIf('_'))
+        return nullptr;
+      Node *SecondType = getDerived().parseType();
+      if (SecondType == nullptr)
+        return nullptr;
+      return make<CtorVtableSpecialName>(SecondType, FirstType);
+    }
+    // TW <object name> # Thread-local wrapper
+    case 'W': {
+      First += 2;
+      Node *Name = getDerived().parseName();
+      if (Name == nullptr)
+        return nullptr;
+      return make<SpecialName>("thread-local wrapper routine for ", Name);
+    }
+    // TH <object name> # Thread-local initialization
+    case 'H': {
+      First += 2;
+      Node *Name = getDerived().parseName();
+      if (Name == nullptr)
+        return nullptr;
+      return make<SpecialName>("thread-local initialization routine for ", Name);
+    }
+    // T <call-offset> <base encoding>
+    default: {
+      ++First;
+      bool IsVirt = look() == 'v';
+      if (parseCallOffset())
+        return nullptr;
+      Node *BaseEncoding = getDerived().parseEncoding();
+      if (BaseEncoding == nullptr)
+        return nullptr;
+      if (IsVirt)
+        return make<SpecialName>("virtual thunk to ", BaseEncoding);
+      else
+        return make<SpecialName>("non-virtual thunk to ", BaseEncoding);
+    }
+    }
+  case 'G':
+    switch (look(1)) {
+    // GV <object name> # Guard variable for one-time initialization
+    case 'V': {
+      First += 2;
+      Node *Name = getDerived().parseName();
+      if (Name == nullptr)
+        return nullptr;
+      return make<SpecialName>("guard variable for ", Name);
+    }
+    // GR <object name> # reference temporary for object
+    // GR <object name> _             # First temporary
+    // GR <object name> <seq-id> _    # Subsequent temporaries
+    case 'R': {
+      First += 2;
+      Node *Name = getDerived().parseName();
+      if (Name == nullptr)
+        return nullptr;
+      size_t Count;
+      bool ParsedSeqId = !parseSeqId(&Count);
+      if (!consumeIf('_') && ParsedSeqId)
+        return nullptr;
+      return make<SpecialName>("reference temporary for ", Name);
+    }
+    }
+  }
+  return nullptr;
+}
+
+// <encoding> ::= <function name> <bare-function-type>
+//            ::= <data name>
+//            ::= <special-name>
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseEncoding() {
+  if (look() == 'G' || look() == 'T')
+    return getDerived().parseSpecialName();
+
+  auto IsEndOfEncoding = [&] {
+    // The set of chars that can potentially follow an <encoding> (none of which
+    // can start a <type>). Enumerating these allows us to avoid speculative
+    // parsing.
+    return numLeft() == 0 || look() == 'E' || look() == '.' || look() == '_';
+  };
+
+  NameState NameInfo(this);
+  Node *Name = getDerived().parseName(&NameInfo);
+  if (Name == nullptr)
+    return nullptr;
+
+  if (resolveForwardTemplateRefs(NameInfo))
+    return nullptr;
+
+  if (IsEndOfEncoding())
+    return Name;
+
+  Node *Attrs = nullptr;
+  if (consumeIf("Ua9enable_ifI")) {
+    size_t BeforeArgs = Names.size();
+    while (!consumeIf('E')) {
+      Node *Arg = getDerived().parseTemplateArg();
+      if (Arg == nullptr)
+        return nullptr;
+      Names.push_back(Arg);
+    }
+    Attrs = make<EnableIfAttr>(popTrailingNodeArray(BeforeArgs));
+    if (!Attrs)
+      return nullptr;
+  }
+
+  Node *ReturnType = nullptr;
+  if (!NameInfo.CtorDtorConversion && NameInfo.EndsWithTemplateArgs) {
+    ReturnType = getDerived().parseType();
+    if (ReturnType == nullptr)
+      return nullptr;
+  }
+
+  if (consumeIf('v'))
+    return make<FunctionEncoding>(ReturnType, Name, NodeArray(),
+                                  Attrs, NameInfo.CVQualifiers,
+                                  NameInfo.ReferenceQualifier);
+
+  size_t ParamsBegin = Names.size();
+  do {
+    Node *Ty = getDerived().parseType();
+    if (Ty == nullptr)
+      return nullptr;
+    Names.push_back(Ty);
+  } while (!IsEndOfEncoding());
+
+  return make<FunctionEncoding>(ReturnType, Name,
+                                popTrailingNodeArray(ParamsBegin),
+                                Attrs, NameInfo.CVQualifiers,
+                                NameInfo.ReferenceQualifier);
+}
+
+template <class Float>
+struct FloatData;
+
+template <>
+struct FloatData<float>
+{
+    static const size_t mangled_size = 8;
+    static const size_t max_demangled_size = 24;
+    static constexpr const char* spec = "%af";
+};
+
+template <>
+struct FloatData<double>
+{
+    static const size_t mangled_size = 16;
+    static const size_t max_demangled_size = 32;
+    static constexpr const char* spec = "%a";
+};
+
+template <>
+struct FloatData<long double>
+{
+#if defined(__mips__) && defined(__mips_n64) || defined(__aarch64__) || \
+    defined(__wasm__)
+    static const size_t mangled_size = 32;
+#elif defined(__arm__) || defined(__mips__) || defined(__hexagon__)
+    static const size_t mangled_size = 16;
+#else
+    static const size_t mangled_size = 20;  // May need to be adjusted to 16 or 24 on other platforms
+#endif
+    static const size_t max_demangled_size = 40;
+    static constexpr const char *spec = "%LaL";
+};
+
+template <typename Alloc, typename Derived>
+template <class Float>
+Node *AbstractManglingParser<Alloc, Derived>::parseFloatingLiteral() {
+  const size_t N = FloatData<Float>::mangled_size;
+  if (numLeft() <= N)
+    return nullptr;
+  StringView Data(First, First + N);
+  for (char C : Data)
+    if (!std::isxdigit(C))
+      return nullptr;
+  First += N;
+  if (!consumeIf('E'))
+    return nullptr;
+  return make<FloatLiteralImpl<Float>>(Data);
+}
+
+// <seq-id> ::= <0-9A-Z>+
+template <typename Alloc, typename Derived>
+bool AbstractManglingParser<Alloc, Derived>::parseSeqId(size_t *Out) {
+  if (!(look() >= '0' && look() <= '9') &&
+      !(look() >= 'A' && look() <= 'Z'))
+    return true;
+
+  size_t Id = 0;
+  while (true) {
+    if (look() >= '0' && look() <= '9') {
+      Id *= 36;
+      Id += static_cast<size_t>(look() - '0');
+    } else if (look() >= 'A' && look() <= 'Z') {
+      Id *= 36;
+      Id += static_cast<size_t>(look() - 'A') + 10;
+    } else {
+      *Out = Id;
+      return false;
+    }
+    ++First;
+  }
+}
+
+// <substitution> ::= S <seq-id> _
+//                ::= S_
+// <substitution> ::= Sa # ::std::allocator
+// <substitution> ::= Sb # ::std::basic_string
+// <substitution> ::= Ss # ::std::basic_string < char,
+//                                               ::std::char_traits<char>,
+//                                               ::std::allocator<char> >
+// <substitution> ::= Si # ::std::basic_istream<char,  std::char_traits<char> >
+// <substitution> ::= So # ::std::basic_ostream<char,  std::char_traits<char> >
+// <substitution> ::= Sd # ::std::basic_iostream<char, std::char_traits<char> >
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseSubstitution() {
+  if (!consumeIf('S'))
+    return nullptr;
+
+  if (std::islower(look())) {
+    Node *SpecialSub;
+    switch (look()) {
+    case 'a':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::allocator);
+      break;
+    case 'b':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::basic_string);
+      break;
+    case 's':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::string);
+      break;
+    case 'i':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::istream);
+      break;
+    case 'o':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::ostream);
+      break;
+    case 'd':
+      ++First;
+      SpecialSub = make<SpecialSubstitution>(SpecialSubKind::iostream);
+      break;
+    default:
+      return nullptr;
+    }
+    if (!SpecialSub)
+      return nullptr;
+    // Itanium C++ ABI 5.1.2: If a name that would use a built-in <substitution>
+    // has ABI tags, the tags are appended to the substitution; the result is a
+    // substitutable component.
+    Node *WithTags = getDerived().parseAbiTags(SpecialSub);
+    if (WithTags != SpecialSub) {
+      Subs.push_back(WithTags);
+      SpecialSub = WithTags;
+    }
+    return SpecialSub;
+  }
+
+  //                ::= S_
+  if (consumeIf('_')) {
+    if (Subs.empty())
+      return nullptr;
+    return Subs[0];
+  }
+
+  //                ::= S <seq-id> _
+  size_t Index = 0;
+  if (parseSeqId(&Index))
+    return nullptr;
+  ++Index;
+  if (!consumeIf('_') || Index >= Subs.size())
+    return nullptr;
+  return Subs[Index];
+}
+
+// <template-param> ::= T_    # first template parameter
+//                  ::= T <parameter-2 non-negative number> _
+//                  ::= TL <level-1> __
+//                  ::= TL <level-1> _ <parameter-2 non-negative number> _
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseTemplateParam() {
+  if (!consumeIf('T'))
+    return nullptr;
+
+  size_t Level = 0;
+  if (consumeIf('L')) {
+    if (parsePositiveInteger(&Level))
+      return nullptr;
+    ++Level;
+    if (!consumeIf('_'))
+      return nullptr;
+  }
+
+  size_t Index = 0;
+  if (!consumeIf('_')) {
+    if (parsePositiveInteger(&Index))
+      return nullptr;
+    ++Index;
+    if (!consumeIf('_'))
+      return nullptr;
+  }
+
+  // If we're in a context where this <template-param> refers to a
+  // <template-arg> further ahead in the mangled name (currently just conversion
+  // operator types), then we should only look it up in the right context.
+  // This can only happen at the outermost level.
+  if (PermitForwardTemplateReferences && Level == 0) {
+    Node *ForwardRef = make<ForwardTemplateReference>(Index);
+    if (!ForwardRef)
+      return nullptr;
+    assert(ForwardRef->getKind() == Node::KForwardTemplateReference);
+    ForwardTemplateRefs.push_back(
+        static_cast<ForwardTemplateReference *>(ForwardRef));
+    return ForwardRef;
+  }
+
+  if (Level >= TemplateParams.size() || !TemplateParams[Level] ||
+      Index >= TemplateParams[Level]->size()) {
+    // Itanium ABI 5.1.8: In a generic lambda, uses of auto in the parameter
+    // list are mangled as the corresponding artificial template type parameter.
+    if (ParsingLambdaParamsAtLevel == Level && Level <= TemplateParams.size()) {
+      // This will be popped by the ScopedTemplateParamList in
+      // parseUnnamedTypeName.
+      if (Level == TemplateParams.size())
+        TemplateParams.push_back(nullptr);
+      return make<NameType>("auto");
+    }
+
+    return nullptr;
+  }
+
+  return (*TemplateParams[Level])[Index];
+}
+
+// <template-param-decl> ::= Ty                          # type parameter
+//                       ::= Tn <type>                   # non-type parameter
+//                       ::= Tt <template-param-decl>* E # template parameter
+//                       ::= Tp <template-param-decl>    # parameter pack
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseTemplateParamDecl() {
+  auto InventTemplateParamName = [&](TemplateParamKind Kind) {
+    unsigned Index = NumSyntheticTemplateParameters[(int)Kind]++;
+    Node *N = make<SyntheticTemplateParamName>(Kind, Index);
+    if (N) TemplateParams.back()->push_back(N);
+    return N;
+  };
+
+  if (consumeIf("Ty")) {
+    Node *Name = InventTemplateParamName(TemplateParamKind::Type);
+    if (!Name)
+      return nullptr;
+    return make<TypeTemplateParamDecl>(Name);
+  }
+
+  if (consumeIf("Tn")) {
+    Node *Name = InventTemplateParamName(TemplateParamKind::NonType);
+    if (!Name)
+      return nullptr;
+    Node *Type = parseType();
+    if (!Type)
+      return nullptr;
+    return make<NonTypeTemplateParamDecl>(Name, Type);
+  }
+
+  if (consumeIf("Tt")) {
+    Node *Name = InventTemplateParamName(TemplateParamKind::Template);
+    if (!Name)
+      return nullptr;
+    size_t ParamsBegin = Names.size();
+    ScopedTemplateParamList TemplateTemplateParamParams(this);
+    while (!consumeIf("E")) {
+      Node *P = parseTemplateParamDecl();
+      if (!P)
+        return nullptr;
+      Names.push_back(P);
+    }
+    NodeArray Params = popTrailingNodeArray(ParamsBegin);
+    return make<TemplateTemplateParamDecl>(Name, Params);
+  }
+
+  if (consumeIf("Tp")) {
+    Node *P = parseTemplateParamDecl();
+    if (!P)
+      return nullptr;
+    return make<TemplateParamPackDecl>(P);
+  }
+
+  return nullptr;
+}
+
+// <template-arg> ::= <type>                    # type or template
+//                ::= X <expression> E          # expression
+//                ::= <expr-primary>            # simple expressions
+//                ::= J <template-arg>* E       # argument pack
+//                ::= LZ <encoding> E           # extension
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parseTemplateArg() {
+  switch (look()) {
+  case 'X': {
+    ++First;
+    Node *Arg = getDerived().parseExpr();
+    if (Arg == nullptr || !consumeIf('E'))
+      return nullptr;
+    return Arg;
+  }
+  case 'J': {
+    ++First;
+    size_t ArgsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *Arg = getDerived().parseTemplateArg();
+      if (Arg == nullptr)
+        return nullptr;
+      Names.push_back(Arg);
+    }
+    NodeArray Args = popTrailingNodeArray(ArgsBegin);
+    return make<TemplateArgumentPack>(Args);
+  }
+  case 'L': {
+    //                ::= LZ <encoding> E           # extension
+    if (look(1) == 'Z') {
+      First += 2;
+      Node *Arg = getDerived().parseEncoding();
+      if (Arg == nullptr || !consumeIf('E'))
+        return nullptr;
+      return Arg;
+    }
+    //                ::= <expr-primary>            # simple expressions
+    return getDerived().parseExprPrimary();
+  }
+  default:
+    return getDerived().parseType();
+  }
+}
+
+// <template-args> ::= I <template-arg>* E
+//     extension, the abi says <template-arg>+
+template <typename Derived, typename Alloc>
+Node *
+AbstractManglingParser<Derived, Alloc>::parseTemplateArgs(bool TagTemplates) {
+  if (!consumeIf('I'))
+    return nullptr;
+
+  // <template-params> refer to the innermost <template-args>. Clear out any
+  // outer args that we may have inserted into TemplateParams.
+  if (TagTemplates) {
+    TemplateParams.clear();
+    TemplateParams.push_back(&OuterTemplateParams);
+    OuterTemplateParams.clear();
+  }
+
+  size_t ArgsBegin = Names.size();
+  while (!consumeIf('E')) {
+    if (TagTemplates) {
+      auto OldParams = std::move(TemplateParams);
+      Node *Arg = getDerived().parseTemplateArg();
+      TemplateParams = std::move(OldParams);
+      if (Arg == nullptr)
+        return nullptr;
+      Names.push_back(Arg);
+      Node *TableEntry = Arg;
+      if (Arg->getKind() == Node::KTemplateArgumentPack) {
+        TableEntry = make<ParameterPack>(
+            static_cast<TemplateArgumentPack*>(TableEntry)->getElements());
+        if (!TableEntry)
+          return nullptr;
+      }
+      TemplateParams.back()->push_back(TableEntry);
+    } else {
+      Node *Arg = getDerived().parseTemplateArg();
+      if (Arg == nullptr)
+        return nullptr;
+      Names.push_back(Arg);
+    }
+  }
+  return make<TemplateArgs>(popTrailingNodeArray(ArgsBegin));
+}
+
+// <mangled-name> ::= _Z <encoding>
+//                ::= <type>
+// extension      ::= ___Z <encoding> _block_invoke
+// extension      ::= ___Z <encoding> _block_invoke<decimal-digit>+
+// extension      ::= ___Z <encoding> _block_invoke_<decimal-digit>+
+template <typename Derived, typename Alloc>
+Node *AbstractManglingParser<Derived, Alloc>::parse() {
+  if (consumeIf("_Z") || consumeIf("__Z")) {
+    Node *Encoding = getDerived().parseEncoding();
+    if (Encoding == nullptr)
+      return nullptr;
+    if (look() == '.') {
+      Encoding = make<DotSuffix>(Encoding, StringView(First, Last));
+      First = Last;
+    }
+    if (numLeft() != 0)
+      return nullptr;
+    return Encoding;
+  }
+
+  if (consumeIf("___Z") || consumeIf("____Z")) {
+    Node *Encoding = getDerived().parseEncoding();
+    if (Encoding == nullptr || !consumeIf("_block_invoke"))
+      return nullptr;
+    bool RequireNumber = consumeIf('_');
+    if (parseNumber().empty() && RequireNumber)
+      return nullptr;
+    if (look() == '.')
+      First = Last;
+    if (numLeft() != 0)
+      return nullptr;
+    return make<SpecialName>("invocation function for block in ", Encoding);
+  }
+
+  Node *Ty = getDerived().parseType();
+  if (numLeft() != 0)
+    return nullptr;
+  return Ty;
+}
+
+template <typename Alloc>
+struct ManglingParser : AbstractManglingParser<ManglingParser<Alloc>, Alloc> {
+  using AbstractManglingParser<ManglingParser<Alloc>,
+                               Alloc>::AbstractManglingParser;
+};
+
+DEMANGLE_NAMESPACE_END
+
+#endif // DEMANGLE_ITANIUMDEMANGLE_H
diff --git a/externals/demangle/StringView.h b/externals/demangle/StringView.h
new file mode 100644
index 000000000..44d2b18a3
--- /dev/null
+++ b/externals/demangle/StringView.h
@@ -0,0 +1,127 @@
+//===--- StringView.h -------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// FIXME: Use std::string_view instead when we support C++17.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef DEMANGLE_STRINGVIEW_H
+#define DEMANGLE_STRINGVIEW_H
+
+#include "DemangleConfig.h"
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+
+DEMANGLE_NAMESPACE_BEGIN
+
+class StringView {
+  const char *First;
+  const char *Last;
+
+public:
+  static const size_t npos = ~size_t(0);
+
+  template <size_t N>
+  StringView(const char (&Str)[N]) : First(Str), Last(Str + N - 1) {}
+  StringView(const char *First_, const char *Last_)
+      : First(First_), Last(Last_) {}
+  StringView(const char *First_, size_t Len)
+      : First(First_), Last(First_ + Len) {}
+  StringView(const char *Str) : First(Str), Last(Str + std::strlen(Str)) {}
+  StringView() : First(nullptr), Last(nullptr) {}
+
+  StringView substr(size_t From) const {
+    return StringView(begin() + From, size() - From);
+  }
+
+  size_t find(char C, size_t From = 0) const {
+    size_t FindBegin = std::min(From, size());
+    // Avoid calling memchr with nullptr.
+    if (FindBegin < size()) {
+      // Just forward to memchr, which is faster than a hand-rolled loop.
+      if (const void *P = ::memchr(First + FindBegin, C, size() - FindBegin))
+        return size_t(static_cast<const char *>(P) - First);
+    }
+    return npos;
+  }
+
+  StringView substr(size_t From, size_t To) const {
+    if (To >= size())
+      To = size() - 1;
+    if (From >= size())
+      From = size() - 1;
+    return StringView(First + From, First + To);
+  }
+
+  StringView dropFront(size_t N = 1) const {
+    if (N >= size())
+      N = size();
+    return StringView(First + N, Last);
+  }
+
+  StringView dropBack(size_t N = 1) const {
+    if (N >= size())
+      N = size();
+    return StringView(First, Last - N);
+  }
+
+  char front() const {
+    assert(!empty());
+    return *begin();
+  }
+
+  char back() const {
+    assert(!empty());
+    return *(end() - 1);
+  }
+
+  char popFront() {
+    assert(!empty());
+    return *First++;
+  }
+
+  bool consumeFront(char C) {
+    if (!startsWith(C))
+      return false;
+    *this = dropFront(1);
+    return true;
+  }
+
+  bool consumeFront(StringView S) {
+    if (!startsWith(S))
+      return false;
+    *this = dropFront(S.size());
+    return true;
+  }
+
+  bool startsWith(char C) const { return !empty() && *begin() == C; }
+
+  bool startsWith(StringView Str) const {
+    if (Str.size() > size())
+      return false;
+    return std::equal(Str.begin(), Str.end(), begin());
+  }
+
+  const char &operator[](size_t Idx) const { return *(begin() + Idx); }
+
+  const char *begin() const { return First; }
+  const char *end() const { return Last; }
+  size_t size() const { return static_cast<size_t>(Last - First); }
+  bool empty() const { return First == Last; }
+};
+
+inline bool operator==(const StringView &LHS, const StringView &RHS) {
+  return LHS.size() == RHS.size() &&
+         std::equal(LHS.begin(), LHS.end(), RHS.begin());
+}
+
+DEMANGLE_NAMESPACE_END
+
+#endif
diff --git a/externals/demangle/Utility.h b/externals/demangle/Utility.h
new file mode 100644
index 000000000..50d05c6b1
--- /dev/null
+++ b/externals/demangle/Utility.h
@@ -0,0 +1,192 @@
+//===--- Utility.h ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-FileCopyrightText: Part of the LLVM Project
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Provide some utility classes for use in the demangler(s).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef DEMANGLE_UTILITY_H
+#define DEMANGLE_UTILITY_H
+
+#include "StringView.h"
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <iterator>
+#include <limits>
+
+DEMANGLE_NAMESPACE_BEGIN
+
+// Stream that AST nodes write their string representation into after the AST
+// has been parsed.
+class OutputStream {
+  char *Buffer;
+  size_t CurrentPosition;
+  size_t BufferCapacity;
+
+  // Ensure there is at least n more positions in buffer.
+  void grow(size_t N) {
+    if (N + CurrentPosition >= BufferCapacity) {
+      BufferCapacity *= 2;
+      if (BufferCapacity < N + CurrentPosition)
+        BufferCapacity = N + CurrentPosition;
+      Buffer = static_cast<char *>(std::realloc(Buffer, BufferCapacity));
+      if (Buffer == nullptr)
+        std::terminate();
+    }
+  }
+
+  void writeUnsigned(uint64_t N, bool isNeg = false) {
+    // Handle special case...
+    if (N == 0) {
+      *this << '0';
+      return;
+    }
+
+    char Temp[21];
+    char *TempPtr = std::end(Temp);
+
+    while (N) {
+      *--TempPtr = '0' + char(N % 10);
+      N /= 10;
+    }
+
+    // Add negative sign...
+    if (isNeg)
+      *--TempPtr = '-';
+    this->operator<<(StringView(TempPtr, std::end(Temp)));
+  }
+
+public:
+  OutputStream(char *StartBuf, size_t Size)
+      : Buffer(StartBuf), CurrentPosition(0), BufferCapacity(Size) {}
+  OutputStream() = default;
+  void reset(char *Buffer_, size_t BufferCapacity_) {
+    CurrentPosition = 0;
+    Buffer = Buffer_;
+    BufferCapacity = BufferCapacity_;
+  }
+
+  /// If a ParameterPackExpansion (or similar type) is encountered, the offset
+  /// into the pack that we're currently printing.
+  unsigned CurrentPackIndex = std::numeric_limits<unsigned>::max();
+  unsigned CurrentPackMax = std::numeric_limits<unsigned>::max();
+
+  OutputStream &operator+=(StringView R) {
+    size_t Size = R.size();
+    if (Size == 0)
+      return *this;
+    grow(Size);
+    std::memmove(Buffer + CurrentPosition, R.begin(), Size);
+    CurrentPosition += Size;
+    return *this;
+  }
+
+  OutputStream &operator+=(char C) {
+    grow(1);
+    Buffer[CurrentPosition++] = C;
+    return *this;
+  }
+
+  OutputStream &operator<<(StringView R) { return (*this += R); }
+
+  OutputStream &operator<<(char C) { return (*this += C); }
+
+  OutputStream &operator<<(long long N) {
+    if (N < 0)
+      writeUnsigned(static_cast<unsigned long long>(-N), true);
+    else
+      writeUnsigned(static_cast<unsigned long long>(N));
+    return *this;
+  }
+
+  OutputStream &operator<<(unsigned long long N) {
+    writeUnsigned(N, false);
+    return *this;
+  }
+
+  OutputStream &operator<<(long N) {
+    return this->operator<<(static_cast<long long>(N));
+  }
+
+  OutputStream &operator<<(unsigned long N) {
+    return this->operator<<(static_cast<unsigned long long>(N));
+  }
+
+  OutputStream &operator<<(int N) {
+    return this->operator<<(static_cast<long long>(N));
+  }
+
+  OutputStream &operator<<(unsigned int N) {
+    return this->operator<<(static_cast<unsigned long long>(N));
+  }
+
+  size_t getCurrentPosition() const { return CurrentPosition; }
+  void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; }
+
+  char back() const {
+    return CurrentPosition ? Buffer[CurrentPosition - 1] : '\0';
+  }
+
+  bool empty() const { return CurrentPosition == 0; }
+
+  char *getBuffer() { return Buffer; }
+  char *getBufferEnd() { return Buffer + CurrentPosition - 1; }
+  size_t getBufferCapacity() { return BufferCapacity; }
+};
+
+template <class T> class SwapAndRestore {
+  T &Restore;
+  T OriginalValue;
+  bool ShouldRestore = true;
+
+public:
+  SwapAndRestore(T &Restore_) : SwapAndRestore(Restore_, Restore_) {}
+
+  SwapAndRestore(T &Restore_, T NewVal)
+      : Restore(Restore_), OriginalValue(Restore) {
+    Restore = std::move(NewVal);
+  }
+  ~SwapAndRestore() {
+    if (ShouldRestore)
+      Restore = std::move(OriginalValue);
+  }
+
+  void shouldRestore(bool ShouldRestore_) { ShouldRestore = ShouldRestore_; }
+
+  void restoreNow(bool Force) {
+    if (!Force && !ShouldRestore)
+      return;
+
+    Restore = std::move(OriginalValue);
+    ShouldRestore = false;
+  }
+
+  SwapAndRestore(const SwapAndRestore &) = delete;
+  SwapAndRestore &operator=(const SwapAndRestore &) = delete;
+};
+
+inline bool initializeOutputStream(char *Buf, size_t *N, OutputStream &S,
+                                   size_t InitSize) {
+  size_t BufferSize;
+  if (Buf == nullptr) {
+    Buf = static_cast<char *>(std::malloc(InitSize));
+    if (Buf == nullptr)
+      return false;
+    BufferSize = InitSize;
+  } else
+    BufferSize = *N;
+
+  S.reset(Buf, BufferSize);
+  return true;
+}
+
+DEMANGLE_NAMESPACE_END
+
+#endif