Update libcxxabi to 16.0.6

0a9e5a8cb8cd8cd03641221da29e1186a61cf984

16 files changed, 1427 insertions, 1468 deletions

diff --git a/contrib/libs/cxxsupp/libcxxabi-parts/ya.make b/contrib/libs/cxxsupp/libcxxabi-parts/ya.make
index f0928bbce5..ffcb60dd9b 100644
--- a/contrib/libs/cxxsupp/libcxxabi-parts/ya.make
+++ b/contrib/libs/cxxsupp/libcxxabi-parts/ya.make
@@ -8,9 +8,9 @@ LICENSE(
     LLVM-exception
 )
 
-VERSION(14.0.6)
+VERSION(16.0.6)
 
-ORIGINAL_SOURCE(https://github.com/llvm/llvm-project/archive/llvmorg-14.0.6.tar.gz)
+ORIGINAL_SOURCE(https://github.com/llvm/llvm-project/archive/llvmorg-16.0.6.tar.gz)
 
 ADDINCL(
     contrib/libs/cxxsupp/libcxxabi/include
diff --git a/contrib/libs/cxxsupp/libcxxabi/include/__cxxabi_config.h b/contrib/libs/cxxsupp/libcxxabi/include/__cxxabi_config.h
index 7bc39ada8d..c97dd656e1 100644
--- a/contrib/libs/cxxsupp/libcxxabi/include/__cxxabi_config.h
+++ b/contrib/libs/cxxsupp/libcxxabi/include/__cxxabi_config.h
@@ -10,7 +10,7 @@
 #define ____CXXABI_CONFIG_H
 
 #if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) &&                 \
-    !defined(__ARM_DWARF_EH__)
+    !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
 #define _LIBCXXABI_ARM_EHABI
 #endif
 
@@ -97,4 +97,10 @@
 #  define _LIBCXXABI_NO_EXCEPTIONS
 #endif
 
+#if defined(_WIN32)
+#define _LIBCXXABI_DTOR_FUNC __thiscall
+#else
+#define _LIBCXXABI_DTOR_FUNC
+#endif
+
 #endif // ____CXXABI_CONFIG_H
diff --git a/contrib/libs/cxxsupp/libcxxabi/include/cxxabi.h b/contrib/libs/cxxsupp/libcxxabi/include/cxxabi.h
index 106c4508c4..d05c523cab 100644
--- a/contrib/libs/cxxsupp/libcxxabi/include/cxxabi.h
+++ b/contrib/libs/cxxsupp/libcxxabi/include/cxxabi.h
@@ -19,7 +19,7 @@
 
 #include <__cxxabi_config.h>
 
-#define _LIBCPPABI_VERSION 1002
+#define _LIBCPPABI_VERSION 15000
 #define _LIBCXXABI_NORETURN  __attribute__((noreturn))
 #define _LIBCXXABI_ALWAYS_COLD __attribute__((cold))
 
@@ -55,11 +55,11 @@ __cxa_free_exception(void *thrown_exception) _NOEXCEPT;
 #ifdef __USING_WASM_EXCEPTIONS__
 extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void
 __cxa_throw(void *thrown_exception, std::type_info *tinfo,
-            void *(*dest)(void *));
+            void *(_LIBCXXABI_DTOR_FUNC *dest)(void *));
 #else
 extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void
 __cxa_throw(void *thrown_exception, std::type_info *tinfo,
-            void (*dest)(void *));
+            void (_LIBCXXABI_DTOR_FUNC *dest)(void *));
 #endif
 
 // 2.5.3 Exception Handlers
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_default_handlers.cpp b/contrib/libs/cxxsupp/libcxxabi/src/cxa_default_handlers.cpp
index e0ccbe1195..7bcfca069f 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_default_handlers.cpp
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_default_handlers.cpp
@@ -10,6 +10,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <exception>
+#include <memory>
 #include <stdlib.h>
 #include "abort_message.h"
 #include "cxxabi.h"
@@ -20,67 +21,69 @@
 
 #if !defined(LIBCXXABI_SILENT_TERMINATE)
 
-_LIBCPP_SAFE_STATIC
-static const char* cause = "uncaught";
+static constinit const char* cause = "uncaught";
+
+#ifndef _LIBCXXABI_NO_EXCEPTIONS
+// Demangle the given string, or return the string as-is in case of an error.
+static std::unique_ptr<char const, void (*)(char const*)> demangle(char const* str)
+{
+#if !defined(LIBCXXABI_NON_DEMANGLING_TERMINATE)
+    if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
+        return {result, [](char const* p) { std::free(const_cast<char*>(p)); }};
+#endif
+    return {str, [](char const*) { /* nothing to free */ }};
+}
 
 __attribute__((noreturn))
 static void demangling_terminate_handler()
 {
-#ifndef _LIBCXXABI_NO_EXCEPTIONS
-    // If there might be an uncaught exception
     using namespace __cxxabiv1;
     __cxa_eh_globals* globals = __cxa_get_globals_fast();
-    if (globals)
+
+    // If there is no uncaught exception, just note that we're terminating
+    if (!globals)
+        abort_message("terminating");
+
+    __cxa_exception* exception_header = globals->caughtExceptions;
+    if (!exception_header)
+        abort_message("terminating");
+
+    _Unwind_Exception* unwind_exception =
+        reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
+
+    // If we're terminating due to a foreign exception
+    if (!__isOurExceptionClass(unwind_exception))
+        abort_message("terminating due to %s foreign exception", cause);
+
+    void* thrown_object =
+        __getExceptionClass(unwind_exception) == kOurDependentExceptionClass ?
+            ((__cxa_dependent_exception*)exception_header)->primaryException :
+            exception_header + 1;
+    const __shim_type_info* thrown_type =
+        static_cast<const __shim_type_info*>(exception_header->exceptionType);
+    auto name = demangle(thrown_type->name());
+    // If the uncaught exception can be caught with std::exception&
+    const __shim_type_info* catch_type =
+        static_cast<const __shim_type_info*>(&typeid(std::exception));
+    if (catch_type->can_catch(thrown_type, thrown_object))
     {
-        __cxa_exception* exception_header = globals->caughtExceptions;
-        // If there is an uncaught exception
-        if (exception_header)
-        {
-            _Unwind_Exception* unwind_exception =
-                reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
-            if (__isOurExceptionClass(unwind_exception))
-            {
-                void* thrown_object =
-                    __getExceptionClass(unwind_exception) == kOurDependentExceptionClass ?
-                        ((__cxa_dependent_exception*)exception_header)->primaryException :
-                        exception_header + 1;
-                const __shim_type_info* thrown_type =
-                    static_cast<const __shim_type_info*>(exception_header->exceptionType);
-#if !defined(LIBCXXABI_NON_DEMANGLING_TERMINATE)
-                // Try to get demangled name of thrown_type
-                int status;
-                char buf[1024];
-                size_t len = sizeof(buf);
-                const char* name = __cxa_demangle(thrown_type->name(), buf, &len, &status);
-                if (status != 0)
-                    name = thrown_type->name();
-#else
-                const char* name = thrown_type->name();
-#endif
-                // If the uncaught exception can be caught with std::exception&
-                const __shim_type_info* catch_type =
-                    static_cast<const __shim_type_info*>(&typeid(std::exception));
-                if (catch_type->can_catch(thrown_type, thrown_object))
-                {
-                    // Include the what() message from the exception
-                    const std::exception* e = static_cast<const std::exception*>(thrown_object);
-                    abort_message("terminating with %s exception of type %s: %s",
-                                  cause, name, e->what());
-                }
-                else
-                    // Else just note that we're terminating with an exception
-                    abort_message("terminating with %s exception of type %s",
-                                   cause, name);
-            }
-            else
-                // Else we're terminating with a foreign exception
-                abort_message("terminating with %s foreign exception", cause);
-        }
+        // Include the what() message from the exception
+        const std::exception* e = static_cast<const std::exception*>(thrown_object);
+        abort_message("terminating due to %s exception of type %s: %s", cause, name.get(), e->what());
     }
-#endif
-    // Else just note that we're terminating
+    else
+    {
+        // Else just note that we're terminating due to an exception
+        abort_message("terminating due to %s exception of type %s", cause, name.get());
+    }
+}
+#else // !_LIBCXXABI_NO_EXCEPTIONS
+__attribute__((noreturn))
+static void demangling_terminate_handler()
+{
     abort_message("terminating");
 }
+#endif // !_LIBCXXABI_NO_EXCEPTIONS
 
 __attribute__((noreturn))
 static void demangling_unexpected_handler()
@@ -91,22 +94,22 @@ static void demangling_unexpected_handler()
 
 static constexpr std::terminate_handler default_terminate_handler = demangling_terminate_handler;
 static constexpr std::terminate_handler default_unexpected_handler = demangling_unexpected_handler;
-#else
+#else // !LIBCXXABI_SILENT_TERMINATE
 static constexpr std::terminate_handler default_terminate_handler = ::abort;
 static constexpr std::terminate_handler default_unexpected_handler = std::terminate;
-#endif
+#endif // !LIBCXXABI_SILENT_TERMINATE
 
 //
 // Global variables that hold the pointers to the current handler
 //
 _LIBCXXABI_DATA_VIS
-_LIBCPP_SAFE_STATIC std::terminate_handler __cxa_terminate_handler = default_terminate_handler;
+constinit std::terminate_handler __cxa_terminate_handler = default_terminate_handler;
 
 _LIBCXXABI_DATA_VIS
-_LIBCPP_SAFE_STATIC std::unexpected_handler __cxa_unexpected_handler = default_unexpected_handler;
+constinit std::unexpected_handler __cxa_unexpected_handler = default_unexpected_handler;
 
 _LIBCXXABI_DATA_VIS
-_LIBCPP_SAFE_STATIC std::new_handler __cxa_new_handler = 0;
+constinit std::new_handler __cxa_new_handler = nullptr;
 
 namespace std
 {
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_demangle.cpp b/contrib/libs/cxxsupp/libcxxabi/src/cxa_demangle.cpp
index bee4cfd5a1..7baac68007 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_demangle.cpp
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_demangle.cpp
@@ -173,6 +173,50 @@ struct DumpVisitor {
       return printStr("TemplateParamKind::Template");
     }
   }
+  void print(Node::Prec P) {
+    switch (P) {
+    case Node::Prec::Primary:
+      return printStr("Node::Prec::Primary");
+    case Node::Prec::Postfix:
+      return printStr("Node::Prec::Postfix");
+    case Node::Prec::Unary:
+      return printStr("Node::Prec::Unary");
+    case Node::Prec::Cast:
+      return printStr("Node::Prec::Cast");
+    case Node::Prec::PtrMem:
+      return printStr("Node::Prec::PtrMem");
+    case Node::Prec::Multiplicative:
+      return printStr("Node::Prec::Multiplicative");
+    case Node::Prec::Additive:
+      return printStr("Node::Prec::Additive");
+    case Node::Prec::Shift:
+      return printStr("Node::Prec::Shift");
+    case Node::Prec::Spaceship:
+      return printStr("Node::Prec::Spaceship");
+    case Node::Prec::Relational:
+      return printStr("Node::Prec::Relational");
+    case Node::Prec::Equality:
+      return printStr("Node::Prec::Equality");
+    case Node::Prec::And:
+      return printStr("Node::Prec::And");
+    case Node::Prec::Xor:
+      return printStr("Node::Prec::Xor");
+    case Node::Prec::Ior:
+      return printStr("Node::Prec::Ior");
+    case Node::Prec::AndIf:
+      return printStr("Node::Prec::AndIf");
+    case Node::Prec::OrIf:
+      return printStr("Node::Prec::OrIf");
+    case Node::Prec::Conditional:
+      return printStr("Node::Prec::Conditional");
+    case Node::Prec::Assign:
+      return printStr("Node::Prec::Assign");
+    case Node::Prec::Comma:
+      return printStr("Node::Prec::Comma");
+    case Node::Prec::Default:
+      return printStr("Node::Prec::Default");
+    }
+  }
 
   void newLine() {
     printStr("\n");
@@ -342,15 +386,12 @@ __cxa_demangle(const char *MangledName, char *Buf, size_t *N, int *Status) {
 
   int InternalStatus = demangle_success;
   Demangler Parser(MangledName, MangledName + std::strlen(MangledName));
-  OutputBuffer O;
-
   Node *AST = Parser.parse();
 
   if (AST == nullptr)
     InternalStatus = demangle_invalid_mangled_name;
-  else if (!initializeOutputBuffer(Buf, N, O, 1024))
-    InternalStatus = demangle_memory_alloc_failure;
   else {
+    OutputBuffer O(Buf, N);
     assert(Parser.ForwardTemplateRefs.empty());
     AST->print(O);
     O += '\0';
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.cpp b/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.cpp
index 82123825af..6c6732b9cf 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.cpp
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.cpp
@@ -275,7 +275,7 @@ void
 // In wasm, destructors return their argument
 __cxa_throw(void *thrown_object, std::type_info *tinfo, void *(_LIBCXXABI_DTOR_FUNC *dest)(void *))
 #else
-__cxa_throw(void *thrown_object, std::type_info *tinfo, void (*dest)(void *))
+__cxa_throw(void *thrown_object, std::type_info *tinfo, void (_LIBCXXABI_DTOR_FUNC *dest)(void *))
 #endif
 {
     __cxa_eh_globals *globals = __cxa_get_globals();
@@ -390,10 +390,11 @@ unwinding with _Unwind_Resume.
 According to ARM EHABI 8.4.1, __cxa_end_cleanup() should not clobber any
 register, thus we have to write this function in assembly so that we can save
 {r1, r2, r3}.  We don't have to save r0 because it is the return value and the
-first argument to _Unwind_Resume().  In addition, we are saving lr in order to
-align the stack to 16 bytes and lr will be used to identify the caller and its
-frame information. _Unwind_Resume never return and we need to keep the original
-lr so just branch to it.
+first argument to _Unwind_Resume().  The function also saves/restores r4 to
+keep the stack aligned and to provide a temp register.  _Unwind_Resume never
+returns and we need to keep the original lr so just branch to it.  When
+targeting bare metal, the function also clobbers ip/r12 to hold the address of
+_Unwind_Resume, which may be too far away for an ordinary branch.
 */
 __attribute__((used)) static _Unwind_Exception *
 __cxa_end_cleanup_impl()
@@ -430,15 +431,19 @@ asm("	.pushsection	.text.__cxa_end_cleanup,\"ax\",%progbits\n"
 #if defined(__ARM_FEATURE_BTI_DEFAULT)
     "	bti\n"
 #endif
-    "	push	{r1, r2, r3, lr}\n"
+    "	push	{r1, r2, r3, r4}\n"
+    "	mov	r4, lr\n"
     "	bl	__cxa_end_cleanup_impl\n"
-    "	pop	{r1, r2, r3, r4}\n"
     "	mov	lr, r4\n"
 #if defined(LIBCXXABI_BAREMETAL)
     "	ldr	r4,	=_Unwind_Resume\n"
-    "	bx	r4\n"
+    "	mov	ip,	r4\n"
+#endif
+    "	pop	{r1, r2, r3, r4}\n"
+#if defined(LIBCXXABI_BAREMETAL)
+    "	bx	ip\n"
 #else
-    "   b _Unwind_Resume\n"
+    "	b	_Unwind_Resume\n"
 #endif
     "	.popsection");
 #endif // defined(_LIBCXXABI_ARM_EHABI)
@@ -493,6 +498,14 @@ __cxa_begin_catch(void* unwind_arg) _NOEXCEPT
             (
                 static_cast<_Unwind_Exception*>(unwind_exception)
             );
+
+#if defined(__MVS__)
+    // Remove the exception object from the linked list of exceptions that the z/OS unwinder
+    // maintains before adding it to the libc++abi list of caught exceptions.
+    // The libc++abi will manage the lifetime of the exception from this point forward.
+    _UnwindZOS_PopException();
+#endif
+
     if (native_exception)
     {
         // Increment the handler count, removing the flag about being rethrown
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.h b/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.h
index 4d1770c314..dd20ba1e88 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.h
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_exception.h
@@ -53,7 +53,7 @@ struct _LIBCXXABI_HIDDEN __cxa_exception {
     // in the beginning of the struct, rather than before unwindHeader.
     void *reserve;
 
-    // This is a new field to support C++ 0x exception_ptr.
+    // This is a new field to support C++11 exception_ptr.
     // For binary compatibility it is at the start of this
     // struct which is prepended to the object thrown in
     // __cxa_allocate_exception.
@@ -64,9 +64,9 @@ struct _LIBCXXABI_HIDDEN __cxa_exception {
     std::type_info *exceptionType;
 #ifdef __USING_WASM_EXCEPTIONS__
     // In wasm, destructors return their argument
-    void *(*exceptionDestructor)(void *);
+    void *(_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
 #else
-    void (*exceptionDestructor)(void *);
+    void (_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
 #endif
     std::unexpected_handler unexpectedHandler;
     std::terminate_handler  terminateHandler;
@@ -87,9 +87,9 @@ struct _LIBCXXABI_HIDDEN __cxa_exception {
 #endif
 
 #if !defined(__LP64__) && !defined(_WIN64) && !defined(_LIBCXXABI_ARM_EHABI)
-    // This is a new field to support C++ 0x exception_ptr.
+    // This is a new field to support C++11 exception_ptr.
     // For binary compatibility it is placed where the compiler
-    // previously adding padded to 64-bit align unwindHeader.
+    // previously added padding to 64-bit align unwindHeader.
     size_t referenceCount;
 #endif
     _Unwind_Exception unwindHeader;
@@ -105,7 +105,7 @@ struct _LIBCXXABI_HIDDEN __cxa_dependent_exception {
 #endif
 
     std::type_info *exceptionType;
-    void (*exceptionDestructor)(void *);
+    void (_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
     std::unexpected_handler unexpectedHandler;
     std::terminate_handler terminateHandler;
 
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_guard_impl.h b/contrib/libs/cxxsupp/libcxxabi/src/cxa_guard_impl.h
index 5a7cbfd5cd..47fe2b20bd 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_guard_impl.h
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_guard_impl.h
@@ -5,6 +5,7 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+
 #ifndef LIBCXXABI_SRC_INCLUDE_CXA_GUARD_IMPL_H
 #define LIBCXXABI_SRC_INCLUDE_CXA_GUARD_IMPL_H
 
@@ -54,9 +55,12 @@
 #  endif
 #endif
 
+#include <__threading_support>
+#include <cstdint>
+#include <cstring>
 #include <limits.h>
 #include <stdlib.h>
-#include <__threading_support>
+
 #ifndef _LIBCXXABI_HAS_NO_THREADS
 #  if defined(__ELF__) && defined(_LIBCXXABI_LINK_PTHREAD_LIB)
 #    pragma comment(lib, "pthread")
@@ -619,7 +623,7 @@ struct GlobalStatic {
   static T instance;
 };
 template <class T>
-_LIBCPP_SAFE_STATIC T GlobalStatic<T>::instance = {};
+_LIBCPP_CONSTINIT T GlobalStatic<T>::instance = {};
 
 enum class Implementation { NoThreads, GlobalMutex, Futex };
 
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/cxa_personality.cpp b/contrib/libs/cxxsupp/libcxxabi/src/cxa_personality.cpp
index 12387bd7ad..1a969265f0 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/cxa_personality.cpp
+++ b/contrib/libs/cxxsupp/libcxxabi/src/cxa_personality.cpp
@@ -22,6 +22,15 @@
 #include "private_typeinfo.h"
 #include "unwind.h"
 
+// TODO: This is a temporary workaround for libc++abi to recognize that it's being
+// built against LLVM's libunwind. LLVM's libunwind started reporting _LIBUNWIND_VERSION
+// in LLVM 15 -- we can remove this workaround after shipping LLVM 17. Once we remove
+// this workaround, it won't be possible to build libc++abi against libunwind headers
+// from LLVM 14 and before anymore.
+#if defined(____LIBUNWIND_CONFIG_H__) && !defined(_LIBUNWIND_VERSION)
+#   define _LIBUNWIND_VERSION
+#endif
+
 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
 #include <windows.h>
 #include <winnt.h>
@@ -615,7 +624,7 @@ static void scan_eh_tab(scan_results &results, _Unwind_Action actions,
         results.reason = _URC_FATAL_PHASE1_ERROR;
         return;
     }
-    // Start scan by getting exception table address
+    // Start scan by getting exception table address.
     const uint8_t *lsda = (const uint8_t *)_Unwind_GetLanguageSpecificData(context);
     if (lsda == 0)
     {
@@ -907,6 +916,8 @@ static _Unwind_Reason_Code __gxx_personality_imp
 _LIBCXXABI_FUNC_VIS _Unwind_Reason_Code
 #ifdef __USING_SJLJ_EXCEPTIONS__
 __gxx_personality_sj0
+#elif defined(__MVS__)
+__zos_cxx_personality_v2
 #else
 __gxx_personality_v0
 #endif
@@ -1024,7 +1035,7 @@ static _Unwind_Reason_Code continue_unwind(_Unwind_Exception* unwind_exception,
 }
 
 // ARM register names
-#if !defined(LIBCXXABI_USE_LLVM_UNWINDER)
+#if !defined(_LIBUNWIND_VERSION)
 static const uint32_t REG_UCB = 12;  // Register to save _Unwind_Control_Block
 #endif
 static const uint32_t REG_SP = 13;
@@ -1059,7 +1070,7 @@ __gxx_personality_v0(_Unwind_State state,
 
     bool native_exception = __isOurExceptionClass(unwind_exception);
 
-#if !defined(LIBCXXABI_USE_LLVM_UNWINDER)
+#if !defined(_LIBUNWIND_VERSION)
     // Copy the address of _Unwind_Control_Block to r12 so that
     // _Unwind_GetLanguageSpecificData() and _Unwind_GetRegionStart() can
     // return correct address.
@@ -1121,7 +1132,7 @@ __gxx_personality_v0(_Unwind_State state,
         }
 
         // Either we didn't do a phase 1 search (due to forced unwinding), or
-        //  phase 1 reported no catching-handlers.
+        // phase 1 reported no catching-handlers.
         // Search for a (non-catching) cleanup
         if (is_force_unwinding)
           scan_eh_tab(
@@ -1305,3 +1316,9 @@ _LIBCXXABI_FUNC_VIS _Unwind_Reason_Code __xlcxx_personality_v1(
 }  // extern "C"
 
 }  // __cxxabiv1
+
+#if defined(_AIX)
+// Include implementation of the personality and helper functions for the
+// state table based EH used by IBM legacy compilers xlC and xlclang++ on AIX.
+#  error #include "aix_state_tab_eh.inc"
+#endif
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumDemangle.h b/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumDemangle.h
index 9b909cd0a8..2f62aa65de 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumDemangle.h
+++ b/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumDemangle.h
@@ -16,10 +16,6 @@
 #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"
@@ -30,88 +26,10 @@
 #include <cstdlib>
 #include <cstring>
 #include <limits>
+#include <new>
 #include <type_traits>
 #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(BinaryFPType) \
-    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(SubobjectExpr) \
-    X(EnclosingExpr) \
-    X(CastExpr) \
-    X(SizeofParamPackExpr) \
-    X(CallExpr) \
-    X(NewExpr) \
-    X(DeleteExpr) \
-    X(PrefixExpr) \
-    X(FunctionParam) \
-    X(ConversionExpr) \
-    X(PointerToMemberConversionExpr) \
-    X(InitListExpr) \
-    X(FoldExpr) \
-    X(ThrowExpr) \
-    X(BoolExpr) \
-    X(StringLiteral) \
-    X(LambdaExpr) \
-    X(EnumLiteral)    \
-    X(IntegerLiteral) \
-    X(FloatLiteral) \
-    X(DoubleLiteral) \
-    X(LongDoubleLiteral) \
-    X(BracedExpr) \
-    X(BracedRangeExpr)
-
 DEMANGLE_NAMESPACE_BEGIN
 
 template <class T, size_t N> class PODSmallVector {
@@ -239,37 +157,68 @@ public:
 class Node {
 public:
   enum Kind : unsigned char {
-#define ENUMERATOR(NodeKind) K ## NodeKind,
-    FOR_EACH_NODE_KIND(ENUMERATOR)
-#undef ENUMERATOR
+#define NODE(NodeKind) K##NodeKind,
+#include "ItaniumNodes.def"
   };
 
   /// 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, };
 
+  /// Operator precedence for expression nodes. Used to determine required
+  /// parens in expression emission.
+  enum class Prec {
+    Primary,
+    Postfix,
+    Unary,
+    Cast,
+    PtrMem,
+    Multiplicative,
+    Additive,
+    Shift,
+    Spaceship,
+    Relational,
+    Equality,
+    And,
+    Xor,
+    Ior,
+    AndIf,
+    OrIf,
+    Conditional,
+    Assign,
+    Comma,
+    Default,
+  };
+
 private:
   Kind K;
 
+  Prec Precedence : 6;
+
   // 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;
+  Cache RHSComponentCache : 2;
 
   /// Track if this node is a (possibly qualified) array type. This can affect
   /// how we format the output string.
-  Cache ArrayCache;
+  Cache ArrayCache : 2;
 
   /// Track if this node is a (possibly qualified) function type. This can
   /// affect how we format the output string.
-  Cache FunctionCache;
+  Cache FunctionCache : 2;
 
 public:
-  Node(Kind K_, Cache RHSComponentCache_ = Cache::No,
-       Cache ArrayCache_ = Cache::No, Cache FunctionCache_ = Cache::No)
-      : K(K_), RHSComponentCache(RHSComponentCache_), ArrayCache(ArrayCache_),
-        FunctionCache(FunctionCache_) {}
+  Node(Kind K_, Prec Precedence_ = Prec::Primary,
+       Cache RHSComponentCache_ = Cache::No, Cache ArrayCache_ = Cache::No,
+       Cache FunctionCache_ = Cache::No)
+      : K(K_), Precedence(Precedence_), RHSComponentCache(RHSComponentCache_),
+        ArrayCache(ArrayCache_), FunctionCache(FunctionCache_) {}
+  Node(Kind K_, Cache RHSComponentCache_, Cache ArrayCache_ = Cache::No,
+       Cache FunctionCache_ = Cache::No)
+      : Node(K_, Prec::Primary, RHSComponentCache_, ArrayCache_,
+             FunctionCache_) {}
 
   /// Visit the most-derived object corresponding to this object.
   template<typename Fn> void visit(Fn F) const;
@@ -300,6 +249,8 @@ public:
 
   Kind getKind() const { return K; }
 
+  Prec getPrecedence() const { return Precedence; }
+
   virtual bool hasRHSComponentSlow(OutputBuffer &) const { return false; }
   virtual bool hasArraySlow(OutputBuffer &) const { return false; }
   virtual bool hasFunctionSlow(OutputBuffer &) const { return false; }
@@ -308,6 +259,19 @@ public:
   // get at a node that actually represents some concrete syntax.
   virtual const Node *getSyntaxNode(OutputBuffer &) const { return this; }
 
+  // Print this node as an expression operand, surrounding it in parentheses if
+  // its precedence is [Strictly] weaker than P.
+  void printAsOperand(OutputBuffer &OB, Prec P = Prec::Default,
+                      bool StrictlyWorse = false) const {
+    bool Paren =
+        unsigned(getPrecedence()) >= unsigned(P) + unsigned(StrictlyWorse);
+    if (Paren)
+      OB.printOpen();
+    print(OB);
+    if (Paren)
+      OB.printClose();
+  }
+
   void print(OutputBuffer &OB) const {
     printLeft(OB);
     if (RHSComponentCache != Cache::No)
@@ -357,7 +321,7 @@ public:
       if (!FirstElement)
         OB += ", ";
       size_t AfterComma = OB.getCurrentPosition();
-      Elements[Idx]->print(OB);
+      Elements[Idx]->printAsOperand(OB, Node::Prec::Comma);
 
       // Elements[Idx] is an empty parameter pack expansion, we should erase the
       // comma we just printed.
@@ -407,6 +371,10 @@ public:
   VendorExtQualType(const Node *Ty_, StringView Ext_, const Node *TA_)
       : Node(KVendorExtQualType), Ty(Ty_), Ext(Ext_), TA(TA_) {}
 
+  const Node *getTy() const { return Ty; }
+  StringView getExt() const { return Ext; }
+  const Node *getTA() const { return TA; }
+
   template <typename Fn> void match(Fn F) const { F(Ty, Ext, TA); }
 
   void printLeft(OutputBuffer &OB) const override {
@@ -455,6 +423,9 @@ public:
              Child_->ArrayCache, Child_->FunctionCache),
         Quals(Quals_), Child(Child_) {}
 
+  Qualifiers getQuals() const { return Quals; }
+  const Node *getChild() const { return Child; }
+
   template<typename Fn> void match(Fn F) const { F(Child, Quals); }
 
   bool hasRHSComponentSlow(OutputBuffer &OB) const override {
@@ -495,7 +466,7 @@ class PostfixQualifiedType final : public Node {
   const StringView Postfix;
 
 public:
-  PostfixQualifiedType(Node *Ty_, StringView Postfix_)
+  PostfixQualifiedType(const Node *Ty_, StringView Postfix_)
       : Node(KPostfixQualifiedType), Ty(Ty_), Postfix(Postfix_) {}
 
   template<typename Fn> void match(Fn F) const { F(Ty, Postfix); }
@@ -520,6 +491,26 @@ public:
   void printLeft(OutputBuffer &OB) const override { OB += Name; }
 };
 
+class BitIntType final : public Node {
+  const Node *Size;
+  bool Signed;
+
+public:
+  BitIntType(const Node *Size_, bool Signed_)
+      : Node(KBitIntType), Size(Size_), Signed(Signed_) {}
+
+  template <typename Fn> void match(Fn F) const { F(Size, Signed); }
+
+  void printLeft(OutputBuffer &OB) const override {
+    if (!Signed)
+      OB += "unsigned ";
+    OB += "_BitInt";
+    OB.printOpen();
+    Size->printAsOperand(OB);
+    OB.printClose();
+  }
+};
+
 class ElaboratedTypeSpefType : public Node {
   StringView Kind;
   Node *Child;
@@ -603,6 +594,8 @@ public:
       : Node(KPointerType, Pointee_->RHSComponentCache),
         Pointee(Pointee_) {}
 
+  const Node *getPointee() const { return Pointee; }
+
   template<typename Fn> void match(Fn F) const { F(Pointee); }
 
   bool hasRHSComponentSlow(OutputBuffer &OB) const override {
@@ -694,7 +687,7 @@ public:
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -709,7 +702,7 @@ public:
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     std::pair<ReferenceKind, const Node *> Collapsed = collapse(OB);
     if (!Collapsed.second)
       return;
@@ -816,9 +809,9 @@ public:
   }
 
   void printRight(OutputBuffer &OB) const override {
-    OB += "(";
+    OB.printOpen();
     Params.printWithComma(OB);
-    OB += ")";
+    OB.printClose();
     Ret->printRight(OB);
 
     if (CVQuals & QualConst)
@@ -848,9 +841,10 @@ public:
   template<typename Fn> void match(Fn F) const { F(E); }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "noexcept(";
-    E->print(OB);
-    OB += ")";
+    OB += "noexcept";
+    OB.printOpen();
+    E->printAsOperand(OB);
+    OB.printClose();
   }
 };
 
@@ -863,9 +857,10 @@ public:
   template<typename Fn> void match(Fn F) const { F(Types); }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "throw(";
+    OB += "throw";
+    OB.printOpen();
     Types.printWithComma(OB);
-    OB += ')';
+    OB.printClose();
   }
 };
 
@@ -911,9 +906,9 @@ public:
   }
 
   void printRight(OutputBuffer &OB) const override {
-    OB += "(";
+    OB.printOpen();
     Params.printWithComma(OB);
-    OB += ")";
+    OB.printClose();
     if (Ret)
       Ret->printRight(OB);
 
@@ -1002,6 +997,46 @@ struct NestedName : Node {
   }
 };
 
+struct ModuleName : Node {
+  ModuleName *Parent;
+  Node *Name;
+  bool IsPartition;
+
+  ModuleName(ModuleName *Parent_, Node *Name_, bool IsPartition_ = false)
+      : Node(KModuleName), Parent(Parent_), Name(Name_),
+        IsPartition(IsPartition_) {}
+
+  template <typename Fn> void match(Fn F) const {
+    F(Parent, Name, IsPartition);
+  }
+
+  void printLeft(OutputBuffer &OB) const override {
+    if (Parent)
+      Parent->print(OB);
+    if (Parent || IsPartition)
+      OB += IsPartition ? ':' : '.';
+    Name->print(OB);
+  }
+};
+
+struct ModuleEntity : Node {
+  ModuleName *Module;
+  Node *Name;
+
+  ModuleEntity(ModuleName *Module_, Node *Name_)
+      : Node(KModuleEntity), Module(Module_), Name(Name_) {}
+
+  template <typename Fn> void match(Fn F) const { F(Module, Name); }
+
+  StringView getBaseName() const override { return Name->getBaseName(); }
+
+  void printLeft(OutputBuffer &OB) const override {
+    Name->print(OB);
+    OB += '@';
+    Module->print(OB);
+  }
+};
+
 struct LocalName : Node {
   Node *Encoding;
   Node *Entity;
@@ -1043,9 +1078,11 @@ class VectorType final : public Node {
   const Node *Dimension;
 
 public:
-  VectorType(const Node *BaseType_, Node *Dimension_)
-      : Node(KVectorType), BaseType(BaseType_),
-        Dimension(Dimension_) {}
+  VectorType(const Node *BaseType_, const Node *Dimension_)
+      : Node(KVectorType), BaseType(BaseType_), Dimension(Dimension_) {}
+
+  const Node *getBaseType() const { return BaseType; }
+  const Node *getDimension() const { return Dimension; }
 
   template<typename Fn> void match(Fn F) const { F(BaseType, Dimension); }
 
@@ -1177,6 +1214,7 @@ public:
   template<typename Fn> void match(Fn F) const { F(Name, Params); }
 
   void printLeft(OutputBuffer &OB) const override {
+    ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "template<";
     Params.printWithComma(OB);
     OB += "> typename ";
@@ -1312,8 +1350,8 @@ public:
 
   void printLeft(OutputBuffer &OB) const override {
     constexpr unsigned Max = std::numeric_limits<unsigned>::max();
-    SwapAndRestore<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
-    SwapAndRestore<unsigned> SavePackMax(OB.CurrentPackMax, Max);
+    ScopedOverride<unsigned> SavePackIdx(OB.CurrentPackIndex, Max);
+    ScopedOverride<unsigned> SavePackMax(OB.CurrentPackMax, Max);
     size_t StreamPos = OB.getCurrentPosition();
 
     // Print the first element in the pack. If Child contains a ParameterPack,
@@ -1354,10 +1392,9 @@ public:
   NodeArray getParams() { return Params; }
 
   void printLeft(OutputBuffer &OB) const override {
+    ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
     OB += "<";
     Params.printWithComma(OB);
-    if (OB.back() == '>')
-      OB += " ";
     OB += ">";
   }
 };
@@ -1403,38 +1440,38 @@ struct ForwardTemplateReference : Node {
   bool hasRHSComponentSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     return Ref->hasRHSComponent(OB);
   }
   bool hasArraySlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     return Ref->hasArray(OB);
   }
   bool hasFunctionSlow(OutputBuffer &OB) const override {
     if (Printing)
       return false;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     return Ref->hasFunction(OB);
   }
   const Node *getSyntaxNode(OutputBuffer &OB) const override {
     if (Printing)
       return this;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     return Ref->getSyntaxNode(OB);
   }
 
   void printLeft(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     Ref->printLeft(OB);
   }
   void printRight(OutputBuffer &OB) const override {
     if (Printing)
       return;
-    SwapAndRestore<bool> SavePrinting(Printing, true);
+    ScopedOverride<bool> SavePrinting(Printing, true);
     Ref->printRight(OB);
   }
 };
@@ -1474,21 +1511,6 @@ public:
   }
 };
 
-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(OutputBuffer &OB) const override {
-    OB += "std::";
-    Child->print(OB);
-  }
-};
-
 enum class SpecialSubKind {
   allocator,
   basic_string,
@@ -1498,15 +1520,25 @@ enum class SpecialSubKind {
   iostream,
 };
 
-class ExpandedSpecialSubstitution final : public Node {
+class SpecialSubstitution;
+class ExpandedSpecialSubstitution : public Node {
+protected:
   SpecialSubKind SSK;
 
+  ExpandedSpecialSubstitution(SpecialSubKind SSK_, Kind K_)
+      : Node(K_), SSK(SSK_) {}
 public:
   ExpandedSpecialSubstitution(SpecialSubKind SSK_)
-      : Node(KExpandedSpecialSubstitution), SSK(SSK_) {}
+      : ExpandedSpecialSubstitution(SSK_, KExpandedSpecialSubstitution) {}
+  inline ExpandedSpecialSubstitution(SpecialSubstitution const *);
 
   template<typename Fn> void match(Fn F) const { F(SSK); }
 
+protected:
+  bool isInstantiation() const {
+    return unsigned(SSK) >= unsigned(SpecialSubKind::string);
+  }
+
   StringView getBaseName() const override {
     switch (SSK) {
     case SpecialSubKind::allocator:
@@ -1525,82 +1557,44 @@ public:
     DEMANGLE_UNREACHABLE;
   }
 
+private:
   void printLeft(OutputBuffer &OB) const override {
-    switch (SSK) {
-    case SpecialSubKind::allocator:
-      OB += "std::allocator";
-      break;
-    case SpecialSubKind::basic_string:
-      OB += "std::basic_string";
-      break;
-    case SpecialSubKind::string:
-      OB += "std::basic_string<char, std::char_traits<char>, "
-            "std::allocator<char> >";
-      break;
-    case SpecialSubKind::istream:
-      OB += "std::basic_istream<char, std::char_traits<char> >";
-      break;
-    case SpecialSubKind::ostream:
-      OB += "std::basic_ostream<char, std::char_traits<char> >";
-      break;
-    case SpecialSubKind::iostream:
-      OB += "std::basic_iostream<char, std::char_traits<char> >";
-      break;
+    OB << "std::" << getBaseName();
+    if (isInstantiation()) {
+      OB << "<char, std::char_traits<char>";
+      if (SSK == SpecialSubKind::string)
+        OB << ", std::allocator<char>";
+      OB << ">";
     }
   }
 };
 
-class SpecialSubstitution final : public Node {
+class SpecialSubstitution final : public ExpandedSpecialSubstitution {
 public:
-  SpecialSubKind SSK;
-
   SpecialSubstitution(SpecialSubKind SSK_)
-      : Node(KSpecialSubstitution), SSK(SSK_) {}
+      : ExpandedSpecialSubstitution(SSK_, KSpecialSubstitution) {}
 
   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");
+    auto SV = ExpandedSpecialSubstitution::getBaseName ();
+    if (isInstantiation()) {
+      // The instantiations are typedefs that drop the "basic_" prefix.
+      assert(SV.startsWith("basic_"));
+      SV = SV.dropFront(sizeof("basic_") - 1);
     }
-    DEMANGLE_UNREACHABLE;
+    return SV;
   }
 
   void printLeft(OutputBuffer &OB) const override {
-    switch (SSK) {
-    case SpecialSubKind::allocator:
-      OB += "std::allocator";
-      break;
-    case SpecialSubKind::basic_string:
-      OB += "std::basic_string";
-      break;
-    case SpecialSubKind::string:
-      OB += "std::string";
-      break;
-    case SpecialSubKind::istream:
-      OB += "std::istream";
-      break;
-    case SpecialSubKind::ostream:
-      OB += "std::ostream";
-      break;
-    case SpecialSubKind::iostream:
-      OB += "std::iostream";
-      break;
-    }
+    OB << "std::" << getBaseName();
   }
 };
 
+inline ExpandedSpecialSubstitution::ExpandedSpecialSubstitution(
+    SpecialSubstitution const *SS)
+    : ExpandedSpecialSubstitution(SS->SSK) {}
+
 class CtorDtorName final : public Node {
   const Node *Basename;
   const bool IsDtor;
@@ -1666,13 +1660,14 @@ public:
 
   void printDeclarator(OutputBuffer &OB) const {
     if (!TemplateParams.empty()) {
+      ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
       OB += "<";
       TemplateParams.printWithComma(OB);
       OB += ">";
     }
-    OB += "(";
+    OB.printOpen();
     Params.printWithComma(OB);
-    OB += ")";
+    OB.printClose();
   }
 
   void printLeft(OutputBuffer &OB) const override {
@@ -1692,9 +1687,9 @@ public:
   template<typename Fn> void match(Fn F) const { F(Bindings); }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += '[';
+    OB.printOpen('[');
     Bindings.printWithComma(OB);
-    OB += ']';
+    OB.printClose(']');
   }
 };
 
@@ -1706,28 +1701,31 @@ class BinaryExpr : public Node {
   const Node *RHS;
 
 public:
-  BinaryExpr(const Node *LHS_, StringView InfixOperator_, const Node *RHS_)
-      : Node(KBinaryExpr), LHS(LHS_), InfixOperator(InfixOperator_), RHS(RHS_) {
-  }
+  BinaryExpr(const Node *LHS_, StringView InfixOperator_, const Node *RHS_,
+             Prec Prec_)
+      : Node(KBinaryExpr, Prec_), LHS(LHS_), InfixOperator(InfixOperator_),
+        RHS(RHS_) {}
 
-  template<typename Fn> void match(Fn F) const { F(LHS, InfixOperator, RHS); }
+  template <typename Fn> void match(Fn F) const {
+    F(LHS, InfixOperator, RHS, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    // might be a template argument expression, then we need to disambiguate
-    // with parens.
-    if (InfixOperator == ">")
-      OB += "(";
-
-    OB += "(";
-    LHS->print(OB);
-    OB += ") ";
+    bool ParenAll = OB.isGtInsideTemplateArgs() &&
+                    (InfixOperator == ">" || InfixOperator == ">>");
+    if (ParenAll)
+      OB.printOpen();
+    // Assignment is right associative, with special LHS precedence.
+    bool IsAssign = getPrecedence() == Prec::Assign;
+    LHS->printAsOperand(OB, IsAssign ? Prec::OrIf : getPrecedence(), !IsAssign);
+    // No space before comma operator
+    if (!(InfixOperator == ","))
+      OB += " ";
     OB += InfixOperator;
-    OB += " (";
-    RHS->print(OB);
-    OB += ")";
-
-    if (InfixOperator == ">")
-      OB += ")";
+    OB += " ";
+    RHS->printAsOperand(OB, getPrecedence(), IsAssign);
+    if (ParenAll)
+      OB.printClose();
   }
 };
 
@@ -1736,17 +1734,18 @@ class ArraySubscriptExpr : public Node {
   const Node *Op2;
 
 public:
-  ArraySubscriptExpr(const Node *Op1_, const Node *Op2_)
-      : Node(KArraySubscriptExpr), Op1(Op1_), Op2(Op2_) {}
+  ArraySubscriptExpr(const Node *Op1_, const Node *Op2_, Prec Prec_)
+      : Node(KArraySubscriptExpr, Prec_), Op1(Op1_), Op2(Op2_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Op1, Op2); }
+  template <typename Fn> void match(Fn F) const {
+    F(Op1, Op2, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "(";
-    Op1->print(OB);
-    OB += ")[";
-    Op2->print(OB);
-    OB += "]";
+    Op1->printAsOperand(OB, getPrecedence());
+    OB.printOpen('[');
+    Op2->printAsOperand(OB);
+    OB.printClose(']');
   }
 };
 
@@ -1755,15 +1754,15 @@ class PostfixExpr : public Node {
   const StringView Operator;
 
 public:
-  PostfixExpr(const Node *Child_, StringView Operator_)
-      : Node(KPostfixExpr), Child(Child_), Operator(Operator_) {}
+  PostfixExpr(const Node *Child_, StringView Operator_, Prec Prec_)
+      : Node(KPostfixExpr, Prec_), Child(Child_), Operator(Operator_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Child, Operator); }
+  template <typename Fn> void match(Fn F) const {
+    F(Child, Operator, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "(";
-    Child->print(OB);
-    OB += ")";
+    Child->printAsOperand(OB, getPrecedence(), true);
     OB += Operator;
   }
 };
@@ -1774,19 +1773,20 @@ class ConditionalExpr : public Node {
   const Node *Else;
 
 public:
-  ConditionalExpr(const Node *Cond_, const Node *Then_, const Node *Else_)
-      : Node(KConditionalExpr), Cond(Cond_), Then(Then_), Else(Else_) {}
+  ConditionalExpr(const Node *Cond_, const Node *Then_, const Node *Else_,
+                  Prec Prec_)
+      : Node(KConditionalExpr, Prec_), Cond(Cond_), Then(Then_), Else(Else_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Cond, Then, Else); }
+  template <typename Fn> void match(Fn F) const {
+    F(Cond, Then, Else, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "(";
-    Cond->print(OB);
-    OB += ") ? (";
-    Then->print(OB);
-    OB += ") : (";
-    Else->print(OB);
-    OB += ")";
+    Cond->printAsOperand(OB, getPrecedence());
+    OB += " ? ";
+    Then->printAsOperand(OB);
+    OB += " : ";
+    Else->printAsOperand(OB, Prec::Assign, true);
   }
 };
 
@@ -1796,15 +1796,17 @@ class MemberExpr : public Node {
   const Node *RHS;
 
 public:
-  MemberExpr(const Node *LHS_, StringView Kind_, const Node *RHS_)
-      : Node(KMemberExpr), LHS(LHS_), Kind(Kind_), RHS(RHS_) {}
+  MemberExpr(const Node *LHS_, StringView Kind_, const Node *RHS_, Prec Prec_)
+      : Node(KMemberExpr, Prec_), LHS(LHS_), Kind(Kind_), RHS(RHS_) {}
 
-  template<typename Fn> void match(Fn F) const { F(LHS, Kind, RHS); }
+  template <typename Fn> void match(Fn F) const {
+    F(LHS, Kind, RHS, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    LHS->print(OB);
+    LHS->printAsOperand(OB, getPrecedence(), true);
     OB += Kind;
-    RHS->print(OB);
+    RHS->printAsOperand(OB, getPrecedence(), false);
   }
 };
 
@@ -1848,15 +1850,19 @@ class EnclosingExpr : public Node {
   const StringView Postfix;
 
 public:
-  EnclosingExpr(StringView Prefix_, Node *Infix_, StringView Postfix_)
-      : Node(KEnclosingExpr), Prefix(Prefix_), Infix(Infix_),
-        Postfix(Postfix_) {}
+  EnclosingExpr(StringView Prefix_, const Node *Infix_,
+                Prec Prec_ = Prec::Primary)
+      : Node(KEnclosingExpr, Prec_), Prefix(Prefix_), Infix(Infix_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Prefix, Infix, Postfix); }
+  template <typename Fn> void match(Fn F) const {
+    F(Prefix, Infix, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
     OB += Prefix;
+    OB.printOpen();
     Infix->print(OB);
+    OB.printClose();
     OB += Postfix;
   }
 };
@@ -1868,18 +1874,24 @@ class CastExpr : public Node {
   const Node *From;
 
 public:
-  CastExpr(StringView CastKind_, const Node *To_, const Node *From_)
-      : Node(KCastExpr), CastKind(CastKind_), To(To_), From(From_) {}
+  CastExpr(StringView CastKind_, const Node *To_, const Node *From_, Prec Prec_)
+      : Node(KCastExpr, Prec_), CastKind(CastKind_), To(To_), From(From_) {}
 
-  template<typename Fn> void match(Fn F) const { F(CastKind, To, From); }
+  template <typename Fn> void match(Fn F) const {
+    F(CastKind, To, From, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
     OB += CastKind;
-    OB += "<";
-    To->printLeft(OB);
-    OB += ">(";
-    From->printLeft(OB);
-    OB += ")";
+    {
+      ScopedOverride<unsigned> LT(OB.GtIsGt, 0);
+      OB += "<";
+      To->printLeft(OB);
+      OB += ">";
+    }
+    OB.printOpen();
+    From->printAsOperand(OB);
+    OB.printClose();
   }
 };
 
@@ -1893,10 +1905,11 @@ public:
   template<typename Fn> void match(Fn F) const { F(Pack); }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "sizeof...(";
+    OB += "sizeof...";
+    OB.printOpen();
     ParameterPackExpansion PPE(Pack);
     PPE.printLeft(OB);
-    OB += ")";
+    OB.printClose();
   }
 };
 
@@ -1905,16 +1918,18 @@ class CallExpr : public Node {
   NodeArray Args;
 
 public:
-  CallExpr(const Node *Callee_, NodeArray Args_)
-      : Node(KCallExpr), Callee(Callee_), Args(Args_) {}
+  CallExpr(const Node *Callee_, NodeArray Args_, Prec Prec_)
+      : Node(KCallExpr, Prec_), Callee(Callee_), Args(Args_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Callee, Args); }
+  template <typename Fn> void match(Fn F) const {
+    F(Callee, Args, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
     Callee->print(OB);
-    OB += "(";
+    OB.printOpen();
     Args.printWithComma(OB);
-    OB += ")";
+    OB.printClose();
   }
 };
 
@@ -1927,31 +1942,31 @@ class NewExpr : public Node {
   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_) {}
+          bool IsArray_, Prec Prec_)
+      : Node(KNewExpr, Prec_), ExprList(ExprList_), Type(Type_),
+        InitList(InitList_), IsGlobal(IsGlobal_), IsArray(IsArray_) {}
 
   template<typename Fn> void match(Fn F) const {
-    F(ExprList, Type, InitList, IsGlobal, IsArray);
+    F(ExprList, Type, InitList, IsGlobal, IsArray, getPrecedence());
   }
 
   void printLeft(OutputBuffer &OB) const override {
     if (IsGlobal)
-      OB += "::operator ";
+      OB += "::";
     OB += "new";
     if (IsArray)
       OB += "[]";
-    OB += ' ';
     if (!ExprList.empty()) {
-      OB += "(";
+      OB.printOpen();
       ExprList.printWithComma(OB);
-      OB += ")";
+      OB.printClose();
     }
+    OB += " ";
     Type->print(OB);
     if (!InitList.empty()) {
-      OB += "(";
+      OB.printOpen();
       InitList.printWithComma(OB);
-      OB += ")";
+      OB.printClose();
     }
   }
 };
@@ -1962,17 +1977,21 @@ class DeleteExpr : public Node {
   bool IsArray;
 
 public:
-  DeleteExpr(Node *Op_, bool IsGlobal_, bool IsArray_)
-      : Node(KDeleteExpr), Op(Op_), IsGlobal(IsGlobal_), IsArray(IsArray_) {}
+  DeleteExpr(Node *Op_, bool IsGlobal_, bool IsArray_, Prec Prec_)
+      : Node(KDeleteExpr, Prec_), Op(Op_), IsGlobal(IsGlobal_),
+        IsArray(IsArray_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Op, IsGlobal, IsArray); }
+  template <typename Fn> void match(Fn F) const {
+    F(Op, IsGlobal, IsArray, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
     if (IsGlobal)
       OB += "::";
     OB += "delete";
     if (IsArray)
-      OB += "[] ";
+      OB += "[]";
+    OB += ' ';
     Op->print(OB);
   }
 };
@@ -1982,16 +2001,16 @@ class PrefixExpr : public Node {
   Node *Child;
 
 public:
-  PrefixExpr(StringView Prefix_, Node *Child_)
-      : Node(KPrefixExpr), Prefix(Prefix_), Child(Child_) {}
+  PrefixExpr(StringView Prefix_, Node *Child_, Prec Prec_)
+      : Node(KPrefixExpr, Prec_), Prefix(Prefix_), Child(Child_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Prefix, Child); }
+  template <typename Fn> void match(Fn F) const {
+    F(Prefix, Child, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
     OB += Prefix;
-    OB += "(";
-    Child->print(OB);
-    OB += ")";
+    Child->printAsOperand(OB, getPrecedence());
   }
 };
 
@@ -2014,17 +2033,20 @@ class ConversionExpr : public Node {
   NodeArray Expressions;
 
 public:
-  ConversionExpr(const Node *Type_, NodeArray Expressions_)
-      : Node(KConversionExpr), Type(Type_), Expressions(Expressions_) {}
+  ConversionExpr(const Node *Type_, NodeArray Expressions_, Prec Prec_)
+      : Node(KConversionExpr, Prec_), Type(Type_), Expressions(Expressions_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Type, Expressions); }
+  template <typename Fn> void match(Fn F) const {
+    F(Type, Expressions, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "(";
+    OB.printOpen();
     Type->print(OB);
-    OB += ")(";
+    OB.printClose();
+    OB.printOpen();
     Expressions.printWithComma(OB);
-    OB += ")";
+    OB.printClose();
   }
 };
 
@@ -2035,18 +2057,21 @@ class PointerToMemberConversionExpr : public Node {
 
 public:
   PointerToMemberConversionExpr(const Node *Type_, const Node *SubExpr_,
-                                StringView Offset_)
-      : Node(KPointerToMemberConversionExpr), Type(Type_), SubExpr(SubExpr_),
-        Offset(Offset_) {}
+                                StringView Offset_, Prec Prec_)
+      : Node(KPointerToMemberConversionExpr, Prec_), Type(Type_),
+        SubExpr(SubExpr_), Offset(Offset_) {}
 
-  template<typename Fn> void match(Fn F) const { F(Type, SubExpr, Offset); }
+  template <typename Fn> void match(Fn F) const {
+    F(Type, SubExpr, Offset, getPrecedence());
+  }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB += "(";
+    OB.printOpen();
     Type->print(OB);
-    OB += ")(";
+    OB.printClose();
+    OB.printOpen();
     SubExpr->print(OB);
-    OB += ")";
+    OB.printClose();
   }
 };
 
@@ -2132,41 +2157,33 @@ public:
 
   void printLeft(OutputBuffer &OB) const override {
     auto PrintPack = [&] {
-      OB += '(';
+      OB.printOpen();
       ParameterPackExpansion(Pack).print(OB);
-      OB += ')';
+      OB.printClose();
     };
 
-    OB += '(';
-
-    if (IsLeftFold) {
-      // init op ... op pack
-      if (Init != nullptr) {
-        Init->print(OB);
-        OB += ' ';
-        OB += OperatorName;
-        OB += ' ';
-      }
-      // ... op pack
-      OB += "... ";
-      OB += OperatorName;
-      OB += ' ';
-      PrintPack();
-    } else { // !IsLeftFold
-      // pack op ...
-      PrintPack();
-      OB += ' ';
-      OB += OperatorName;
-      OB += " ...";
-      // pack op ... op init
-      if (Init != nullptr) {
-        OB += ' ';
-        OB += OperatorName;
-        OB += ' ';
-        Init->print(OB);
-      }
+    OB.printOpen();
+    // Either '[init op ]... op pack' or 'pack op ...[ op init]'
+    // Refactored to '[(init|pack) op ]...[ op (pack|init)]'
+    // Fold expr operands are cast-expressions
+    if (!IsLeftFold || Init != nullptr) {
+      // '(init|pack) op '
+      if (IsLeftFold)
+        Init->printAsOperand(OB, Prec::Cast, true);
+      else
+        PrintPack();
+      OB << " " << OperatorName << " ";
+    }
+    OB << "...";
+    if (IsLeftFold || Init != nullptr) {
+      // ' op (init|pack)'
+      OB << " " << OperatorName << " ";
+      if (IsLeftFold)
+        PrintPack();
+      else
+        Init->printAsOperand(OB, Prec::Cast, true);
     }
-    OB += ')';
+    OB.printClose();
   }
 };
 
@@ -2240,9 +2257,9 @@ public:
   template<typename Fn> void match(Fn F) const { F(Ty, Integer); }
 
   void printLeft(OutputBuffer &OB) const override {
-    OB << "(";
+    OB.printOpen();
     Ty->print(OB);
-    OB << ")";
+    OB.printClose();
 
     if (Integer[0] == 'n')
       OB << "-" << Integer.dropFront(1);
@@ -2263,13 +2280,13 @@ public:
 
   void printLeft(OutputBuffer &OB) const override {
     if (Type.size() > 3) {
-      OB += "(";
+      OB.printOpen();
       OB += Type;
-      OB += ")";
+      OB.printClose();
     }
 
     if (Value[0] == 'n') {
-      OB += "-";
+      OB += '-';
       OB += Value.dropFront(1);
     } else
       OB += Value;
@@ -2345,24 +2362,22 @@ using LongDoubleLiteral = FloatLiteralImpl<long double>;
 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
+#define NODE(X)                                                                \
+  case K##X:                                                                   \
+    return F(static_cast<const X *>(this));
+#include "ItaniumNodes.def"
   }
   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; } \
+#define NODE(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
+#include "ItaniumNodes.def"
 
 template <typename Derived, typename Alloc> struct AbstractManglingParser {
   const char *First;
@@ -2500,17 +2515,16 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
 
   /// Parse the <expr> production.
   Node *parseExpr();
-  Node *parsePrefixExpr(StringView Kind);
-  Node *parseBinaryExpr(StringView Kind);
+  Node *parsePrefixExpr(StringView Kind, Node::Prec Prec);
+  Node *parseBinaryExpr(StringView Kind, Node::Prec Prec);
   Node *parseIntegerLiteral(StringView Lit);
   Node *parseExprPrimary();
   template <class Float> Node *parseFloatingLiteral();
   Node *parseFunctionParam();
-  Node *parseNewExpr();
   Node *parseConversionExpr();
   Node *parseBracedExpr();
   Node *parseFoldExpr();
-  Node *parsePointerToMemberConversionExpr();
+  Node *parsePointerToMemberConversionExpr(Node::Prec Prec);
   Node *parseSubobjectExpr();
 
   /// Parse the <type> production.
@@ -2558,17 +2572,80 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
   Node *parseName(NameState *State = nullptr);
   Node *parseLocalName(NameState *State);
   Node *parseOperatorName(NameState *State);
-  Node *parseUnqualifiedName(NameState *State);
+  bool parseModuleNameOpt(ModuleName *&Module);
+  Node *parseUnqualifiedName(NameState *State, Node *Scope, ModuleName *Module);
   Node *parseUnnamedTypeName(NameState *State);
   Node *parseSourceName(NameState *State);
-  Node *parseUnscopedName(NameState *State);
+  Node *parseUnscopedName(NameState *State, bool *isSubstName);
   Node *parseNestedName(NameState *State);
   Node *parseCtorDtorName(Node *&SoFar, NameState *State);
 
   Node *parseAbiTags(Node *N);
 
+  struct OperatorInfo {
+    enum OIKind : unsigned char {
+      Prefix,      // Prefix unary: @ expr
+      Postfix,     // Postfix unary: expr @
+      Binary,      // Binary: lhs @ rhs
+      Array,       // Array index:  lhs [ rhs ]
+      Member,      // Member access: lhs @ rhs
+      New,         // New
+      Del,         // Delete
+      Call,        // Function call: expr (expr*)
+      CCast,       // C cast: (type)expr
+      Conditional, // Conditional: expr ? expr : expr
+      NameOnly,    // Overload only, not allowed in expression.
+      // Below do not have operator names
+      NamedCast, // Named cast, @<type>(expr)
+      OfIdOp,    // alignof, sizeof, typeid
+
+      Unnameable = NamedCast,
+    };
+    char Enc[2];      // Encoding
+    OIKind Kind;      // Kind of operator
+    bool Flag : 1;    // Entry-specific flag
+    Node::Prec Prec : 7; // Precedence
+    const char *Name; // Spelling
+
+  public:
+    constexpr OperatorInfo(const char (&E)[3], OIKind K, bool F, Node::Prec P,
+                           const char *N)
+        : Enc{E[0], E[1]}, Kind{K}, Flag{F}, Prec{P}, Name{N} {}
+
+  public:
+    bool operator<(const OperatorInfo &Other) const {
+      return *this < Other.Enc;
+    }
+    bool operator<(const char *Peek) const {
+      return Enc[0] < Peek[0] || (Enc[0] == Peek[0] && Enc[1] < Peek[1]);
+    }
+    bool operator==(const char *Peek) const {
+      return Enc[0] == Peek[0] && Enc[1] == Peek[1];
+    }
+    bool operator!=(const char *Peek) const { return !this->operator==(Peek); }
+
+  public:
+    StringView getSymbol() const {
+      StringView Res = Name;
+      if (Kind < Unnameable) {
+        assert(Res.startsWith("operator") &&
+               "operator name does not start with 'operator'");
+        Res = Res.dropFront(sizeof("operator") - 1);
+        Res.consumeFront(' ');
+      }
+      return Res;
+    }
+    StringView getName() const { return Name; }
+    OIKind getKind() const { return Kind; }
+    bool getFlag() const { return Flag; }
+    Node::Prec getPrecedence() const { return Prec; }
+  };
+  static const OperatorInfo Ops[];
+  static const size_t NumOps;
+  const OperatorInfo *parseOperatorEncoding();
+
   /// Parse the <unresolved-name> production.
-  Node *parseUnresolvedName();
+  Node *parseUnresolvedName(bool Global);
   Node *parseSimpleId();
   Node *parseBaseUnresolvedName();
   Node *parseUnresolvedType();
@@ -2589,26 +2666,16 @@ const char* parse_discriminator(const char* first, const char* last);
 //                          ::= <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);
 
   Node *Result = nullptr;
-  bool IsSubst = look() == 'S' && look(1) != 't';
-  if (IsSubst) {
-    // A substitution must lead to:
-    //        ::= <unscoped-template-name> <template-args>
-    Result = getDerived().parseSubstitution();
-  } else {
-    // An unscoped name can be one of:
-    //        ::= <unscoped-name>
-    //        ::= <unscoped-template-name> <template-args>
-    Result = getDerived().parseUnscopedName(State);
-  }
-  if (Result == nullptr)
+  bool IsSubst = false;
+
+  Result = getDerived().parseUnscopedName(State, &IsSubst);
+  if (!Result)
     return nullptr;
 
   if (look() == 'I') {
@@ -2668,38 +2735,63 @@ Node *AbstractManglingParser<Derived, Alloc>::parseLocalName(NameState *State) {
 
 // <unscoped-name> ::= <unqualified-name>
 //                 ::= St <unqualified-name>   # ::std::
-// extension       ::= StL<unqualified-name>
+// [*] extension
 template <typename Derived, typename Alloc>
 Node *
-AbstractManglingParser<Derived, Alloc>::parseUnscopedName(NameState *State) {
-  bool IsStd = consumeIf("St");
-  if (IsStd)
-    consumeIf('L');
+AbstractManglingParser<Derived, Alloc>::parseUnscopedName(NameState *State,
+                                                          bool *IsSubst) {
 
-  Node *Result = getDerived().parseUnqualifiedName(State);
-  if (Result == nullptr)
-    return nullptr;
-  if (IsStd)
-    Result = make<StdQualifiedName>(Result);
+  Node *Std = nullptr;
+  if (consumeIf("St")) {
+    Std = make<NameType>("std");
+    if (Std == nullptr)
+      return nullptr;
+  }
 
-  return Result;
+  Node *Res = nullptr;
+  ModuleName *Module = nullptr;
+  if (look() == 'S') {
+    Node *S = getDerived().parseSubstitution();
+    if (!S)
+      return nullptr;
+    if (S->getKind() == Node::KModuleName)
+      Module = static_cast<ModuleName *>(S);
+    else if (IsSubst && Std == nullptr) {
+      Res = S;
+      *IsSubst = true;
+    } else {
+      return nullptr;
+    }
+  }
+
+  if (Res == nullptr || Std != nullptr) {
+    Res = getDerived().parseUnqualifiedName(State, Std, Module);
+  }
+
+  return Res;
 }
 
-// <unqualified-name> ::= <operator-name> [abi-tags]
-//                    ::= <ctor-dtor-name>
-//                    ::= <source-name>
-//                    ::= <unnamed-type-name>
-//                    ::= DC <source-name>+ E      # structured binding declaration
+// <unqualified-name> ::= [<module-name>] L? <operator-name> [<abi-tags>]
+//                    ::= [<module-name>] <ctor-dtor-name> [<abi-tags>]
+//                    ::= [<module-name>] L? <source-name> [<abi-tags>]
+//                    ::= [<module-name>] L? <unnamed-type-name> [<abi-tags>]
+//			# structured binding declaration
+//                    ::= [<module-name>] L? DC <source-name>+ E
 template <typename Derived, typename Alloc>
-Node *
-AbstractManglingParser<Derived, Alloc>::parseUnqualifiedName(NameState *State) {
-  // <ctor-dtor-name>s are special-cased in parseNestedName().
+Node *AbstractManglingParser<Derived, Alloc>::parseUnqualifiedName(
+    NameState *State, Node *Scope, ModuleName *Module) {
+  if (getDerived().parseModuleNameOpt(Module))
+    return nullptr;
+
+  consumeIf('L');
+
   Node *Result;
-  if (look() == 'U')
-    Result = getDerived().parseUnnamedTypeName(State);
-  else if (look() >= '1' && look() <= '9')
+  if (look() >= '1' && look() <= '9') {
     Result = getDerived().parseSourceName(State);
-  else if (consumeIf("DC")) {
+  } else if (look() == 'U') {
+    Result = getDerived().parseUnnamedTypeName(State);
+  } else if (consumeIf("DC")) {
+    // Structured binding
     size_t BindingsBegin = Names.size();
     do {
       Node *Binding = getDerived().parseSourceName(State);
@@ -2708,13 +2800,46 @@ AbstractManglingParser<Derived, Alloc>::parseUnqualifiedName(NameState *State) {
       Names.push_back(Binding);
     } while (!consumeIf('E'));
     Result = make<StructuredBindingName>(popTrailingNodeArray(BindingsBegin));
-  } else
+  } else if (look() == 'C' || look() == 'D') {
+    // A <ctor-dtor-name>.
+    if (Scope == nullptr || Module != nullptr)
+      return nullptr;
+    Result = getDerived().parseCtorDtorName(Scope, State);
+  } else {
     Result = getDerived().parseOperatorName(State);
+  }
+
+  if (Result != nullptr && Module != nullptr)
+    Result = make<ModuleEntity>(Module, Result);
   if (Result != nullptr)
     Result = getDerived().parseAbiTags(Result);
+  if (Result != nullptr && Scope != nullptr)
+    Result = make<NestedName>(Scope, Result);
+
   return Result;
 }
 
+// <module-name> ::= <module-subname>
+// 	 	 ::= <module-name> <module-subname>
+//		 ::= <substitution>  # passed in by caller
+// <module-subname> ::= W <source-name>
+//		    ::= W P <source-name>
+template <typename Derived, typename Alloc>
+bool AbstractManglingParser<Derived, Alloc>::parseModuleNameOpt(
+    ModuleName *&Module) {
+  while (consumeIf('W')) {
+    bool IsPartition = consumeIf('P');
+    Node *Sub = getDerived().parseSourceName(nullptr);
+    if (!Sub)
+      return true;
+    Module =
+        static_cast<ModuleName *>(make<ModuleName>(Module, Sub, IsPartition));
+    Subs.push_back(Module);
+  }
+
+  return false;
+}
+
 // <unnamed-type-name> ::= Ut [<nonnegative number>] _
 //                     ::= <closure-type-name>
 //
@@ -2736,7 +2861,7 @@ AbstractManglingParser<Derived, Alloc>::parseUnnamedTypeName(NameState *State) {
     return make<UnnamedTypeName>(Count);
   }
   if (consumeIf("Ul")) {
-    SwapAndRestore<size_t> SwapParams(ParsingLambdaParamsAtLevel,
+    ScopedOverride<size_t> SwapParams(ParsingLambdaParamsAtLevel,
                                       TemplateParams.size());
     ScopedTemplateParamList LambdaTemplateParams(this);
 
@@ -2814,97 +2939,131 @@ Node *AbstractManglingParser<Derived, Alloc>::parseSourceName(NameState *) {
   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    # <=
+// Operator encodings
+template <typename Derived, typename Alloc>
+const typename AbstractManglingParser<
+    Derived, Alloc>::OperatorInfo AbstractManglingParser<Derived,
+                                                         Alloc>::Ops[] = {
+    // Keep ordered by encoding
+    {"aN", OperatorInfo::Binary, false, Node::Prec::Assign, "operator&="},
+    {"aS", OperatorInfo::Binary, false, Node::Prec::Assign, "operator="},
+    {"aa", OperatorInfo::Binary, false, Node::Prec::AndIf, "operator&&"},
+    {"ad", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator&"},
+    {"an", OperatorInfo::Binary, false, Node::Prec::And, "operator&"},
+    {"at", OperatorInfo::OfIdOp, /*Type*/ true, Node::Prec::Unary, "alignof "},
+    {"aw", OperatorInfo::NameOnly, false, Node::Prec::Primary,
+     "operator co_await"},
+    {"az", OperatorInfo::OfIdOp, /*Type*/ false, Node::Prec::Unary, "alignof "},
+    {"cc", OperatorInfo::NamedCast, false, Node::Prec::Postfix, "const_cast"},
+    {"cl", OperatorInfo::Call, false, Node::Prec::Postfix, "operator()"},
+    {"cm", OperatorInfo::Binary, false, Node::Prec::Comma, "operator,"},
+    {"co", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator~"},
+    {"cv", OperatorInfo::CCast, false, Node::Prec::Cast, "operator"}, // C Cast
+    {"dV", OperatorInfo::Binary, false, Node::Prec::Assign, "operator/="},
+    {"da", OperatorInfo::Del, /*Ary*/ true, Node::Prec::Unary,
+     "operator delete[]"},
+    {"dc", OperatorInfo::NamedCast, false, Node::Prec::Postfix, "dynamic_cast"},
+    {"de", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator*"},
+    {"dl", OperatorInfo::Del, /*Ary*/ false, Node::Prec::Unary,
+     "operator delete"},
+    {"ds", OperatorInfo::Member, /*Named*/ false, Node::Prec::PtrMem,
+     "operator.*"},
+    {"dt", OperatorInfo::Member, /*Named*/ false, Node::Prec::Postfix,
+     "operator."},
+    {"dv", OperatorInfo::Binary, false, Node::Prec::Assign, "operator/"},
+    {"eO", OperatorInfo::Binary, false, Node::Prec::Assign, "operator^="},
+    {"eo", OperatorInfo::Binary, false, Node::Prec::Xor, "operator^"},
+    {"eq", OperatorInfo::Binary, false, Node::Prec::Equality, "operator=="},
+    {"ge", OperatorInfo::Binary, false, Node::Prec::Relational, "operator>="},
+    {"gt", OperatorInfo::Binary, false, Node::Prec::Relational, "operator>"},
+    {"ix", OperatorInfo::Array, false, Node::Prec::Postfix, "operator[]"},
+    {"lS", OperatorInfo::Binary, false, Node::Prec::Assign, "operator<<="},
+    {"le", OperatorInfo::Binary, false, Node::Prec::Relational, "operator<="},
+    {"ls", OperatorInfo::Binary, false, Node::Prec::Shift, "operator<<"},
+    {"lt", OperatorInfo::Binary, false, Node::Prec::Relational, "operator<"},
+    {"mI", OperatorInfo::Binary, false, Node::Prec::Assign, "operator-="},
+    {"mL", OperatorInfo::Binary, false, Node::Prec::Assign, "operator*="},
+    {"mi", OperatorInfo::Binary, false, Node::Prec::Additive, "operator-"},
+    {"ml", OperatorInfo::Binary, false, Node::Prec::Multiplicative,
+     "operator*"},
+    {"mm", OperatorInfo::Postfix, false, Node::Prec::Postfix, "operator--"},
+    {"na", OperatorInfo::New, /*Ary*/ true, Node::Prec::Unary,
+     "operator new[]"},
+    {"ne", OperatorInfo::Binary, false, Node::Prec::Equality, "operator!="},
+    {"ng", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator-"},
+    {"nt", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator!"},
+    {"nw", OperatorInfo::New, /*Ary*/ false, Node::Prec::Unary, "operator new"},
+    {"oR", OperatorInfo::Binary, false, Node::Prec::Assign, "operator|="},
+    {"oo", OperatorInfo::Binary, false, Node::Prec::OrIf, "operator||"},
+    {"or", OperatorInfo::Binary, false, Node::Prec::Ior, "operator|"},
+    {"pL", OperatorInfo::Binary, false, Node::Prec::Assign, "operator+="},
+    {"pl", OperatorInfo::Binary, false, Node::Prec::Additive, "operator+"},
+    {"pm", OperatorInfo::Member, /*Named*/ false, Node::Prec::PtrMem,
+     "operator->*"},
+    {"pp", OperatorInfo::Postfix, false, Node::Prec::Postfix, "operator++"},
+    {"ps", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator+"},
+    {"pt", OperatorInfo::Member, /*Named*/ true, Node::Prec::Postfix,
+     "operator->"},
+    {"qu", OperatorInfo::Conditional, false, Node::Prec::Conditional,
+     "operator?"},
+    {"rM", OperatorInfo::Binary, false, Node::Prec::Assign, "operator%="},
+    {"rS", OperatorInfo::Binary, false, Node::Prec::Assign, "operator>>="},
+    {"rc", OperatorInfo::NamedCast, false, Node::Prec::Postfix,
+     "reinterpret_cast"},
+    {"rm", OperatorInfo::Binary, false, Node::Prec::Multiplicative,
+     "operator%"},
+    {"rs", OperatorInfo::Binary, false, Node::Prec::Shift, "operator>>"},
+    {"sc", OperatorInfo::NamedCast, false, Node::Prec::Postfix, "static_cast"},
+    {"ss", OperatorInfo::Binary, false, Node::Prec::Spaceship, "operator<=>"},
+    {"st", OperatorInfo::OfIdOp, /*Type*/ true, Node::Prec::Unary, "sizeof "},
+    {"sz", OperatorInfo::OfIdOp, /*Type*/ false, Node::Prec::Unary, "sizeof "},
+    {"te", OperatorInfo::OfIdOp, /*Type*/ false, Node::Prec::Postfix,
+     "typeid "},
+    {"ti", OperatorInfo::OfIdOp, /*Type*/ true, Node::Prec::Postfix, "typeid "},
+};
+template <typename Derived, typename Alloc>
+const size_t AbstractManglingParser<Derived, Alloc>::NumOps = sizeof(Ops) /
+                                                              sizeof(Ops[0]);
+
+// If the next 2 chars are an operator encoding, consume them and return their
+// OperatorInfo.  Otherwise return nullptr.
+template <typename Derived, typename Alloc>
+const typename AbstractManglingParser<Derived, Alloc>::OperatorInfo *
+AbstractManglingParser<Derived, Alloc>::parseOperatorEncoding() {
+  if (numLeft() < 2)
+    return nullptr;
+
+  // We can't use lower_bound as that can link to symbols in the C++ library,
+  // and this must remain independant of that.
+  size_t lower = 0u, upper = NumOps - 1; // Inclusive bounds.
+  while (upper != lower) {
+    size_t middle = (upper + lower) / 2;
+    if (Ops[middle] < First)
+      lower = middle + 1;
+    else
+      upper = middle;
+  }
+  if (Ops[lower] != First)
+    return nullptr;
+
+  First += 2;
+  return &Ops[lower];
+}
+
+//   <operator-name> ::= See parseOperatorEncoding()
 //                   ::= 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
+//                   ::= 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 (const auto *Op = parseOperatorEncoding()) {
+    if (Op->getKind() == OperatorInfo::CCast) {
+      //              ::= cv <type>    # (cast)
+      ScopedOverride<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,
+      ScopedOverride<bool> SavePermit(PermitForwardTemplateReferences,
                                       PermitForwardTemplateReferences ||
                                           State != nullptr);
       Node *Ty = getDerived().parseType();
@@ -2913,185 +3072,29 @@ AbstractManglingParser<Derived, Alloc>::parseOperatorName(NameState *State) {
       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<=");
+
+    if (Op->getKind() >= OperatorInfo::Unnameable)
+      /* Not a nameable operator.  */
+      return nullptr;
+    if (Op->getKind() == OperatorInfo::Member && !Op->getFlag())
+      /* Not a nameable MemberExpr */
+      return nullptr;
+
+    return make<NameType>(Op->getName());
+  }
+
+  if (consumeIf("li")) {
     //                   ::= 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<LiteralOperator>(SN);
+  }
+
+  if (consumeIf('v')) {
+    // ::= v <digit> <source-name>        # vendor extended operator
+    if (look() >= '0' && look() <= '9') {
+      First++;
       Node *SN = getDerived().parseSourceName(State);
       if (SN == nullptr)
         return nullptr;
@@ -3099,6 +3102,7 @@ AbstractManglingParser<Derived, Alloc>::parseOperatorName(NameState *State) {
     }
     return nullptr;
   }
+
   return nullptr;
 }
 
@@ -3117,19 +3121,11 @@ 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;
-    }
+    // Expand the special substitution.
+    SoFar = make<ExpandedSpecialSubstitution>(
+        static_cast<SpecialSubstitution *>(SoFar));
+    if (!SoFar)
+      return nullptr;
   }
 
   if (consumeIf('C')) {
@@ -3158,8 +3154,10 @@ AbstractManglingParser<Derived, Alloc>::parseCtorDtorName(Node *&SoFar,
   return nullptr;
 }
 
-// <nested-name> ::= N [<CV-Qualifiers>] [<ref-qualifier>] <prefix> <unqualified-name> E
-//               ::= N [<CV-Qualifiers>] [<ref-qualifier>] <template-prefix> <template-args> E
+// <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>
@@ -3168,7 +3166,7 @@ AbstractManglingParser<Derived, Alloc>::parseCtorDtorName(Node *&SoFar,
 //          ::= # empty
 //          ::= <substitution>
 //          ::= <prefix> <data-member-prefix>
-//  extension ::= L
+// [*] extension
 //
 // <data-member-prefix> := <member source-name> [<template-args>] M
 //
@@ -3188,90 +3186,76 @@ AbstractManglingParser<Derived, Alloc>::parseNestedName(NameState *State) {
     if (State) State->ReferenceQualifier = FrefQualRValue;
   } else if (consumeIf('R')) {
     if (State) State->ReferenceQualifier = FrefQualLValue;
-  } else
+  } 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;
   }
 
+  Node *SoFar = 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;
-    }
+    if (State)
+      // Only set end-with-template on the case that does that.
+      State->EndsWithTemplateArgs = false;
 
-    //          ::= <template-param>
     if (look() == 'T') {
-      if (!PushComponent(getDerived().parseTemplateParam()))
-        return nullptr;
-      Subs.push_back(SoFar);
-      continue;
-    }
-
-    //          ::= <template-prefix> <template-args>
-    if (look() == 'I') {
+      //          ::= <template-param>
+      if (SoFar != nullptr)
+        return nullptr; // Cannot have a prefix.
+      SoFar = getDerived().parseTemplateParam();
+    } else if (look() == 'I') {
+      //          ::= <template-prefix> <template-args>
+      if (SoFar == nullptr)
+        return nullptr; // Must have a prefix.
       Node *TA = getDerived().parseTemplateArgs(State != nullptr);
-      if (TA == nullptr || SoFar == nullptr)
-        return nullptr;
-      SoFar = make<NameWithTemplateArgs>(SoFar, TA);
-      if (!SoFar)
+      if (TA == nullptr)
         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()))
+      if (SoFar->getKind() == Node::KNameWithTemplateArgs)
+        // Semantically <template-args> <template-args> cannot be generated by a
+        // C++ entity.  There will always be [something like] a name between
+        // them.
         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;
-    }
+      if (State)
+        State->EndsWithTemplateArgs = true;
+      SoFar = make<NameWithTemplateArgs>(SoFar, TA);
+    } else if (look() == 'D' && (look(1) == 't' || look(1) == 'T')) {
+      //          ::= <decltype>
+      if (SoFar != nullptr)
+        return nullptr; // Cannot have a prefix.
+      SoFar = getDerived().parseDecltype();
+    } else {
+      ModuleName *Module = nullptr;
+
+      if (look() == 'S') {
+        //          ::= <substitution>
+        Node *S = nullptr;
+        if (look(1) == 't') {
+          First += 2;
+          S = make<NameType>("std");
+        } else {
+          S = getDerived().parseSubstitution();
+        }
+        if (!S)
+          return nullptr;
+        if (S->getKind() == Node::KModuleName) {
+          Module = static_cast<ModuleName *>(S);
+        } else if (SoFar != nullptr) {
+          return nullptr; // Cannot have a prefix.
+        } else {
+          SoFar = S;
+          continue; // Do not push a new substitution.
+        }
+      }
 
-    // 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>
+      SoFar = getDerived().parseUnqualifiedName(State, SoFar, Module);
     }
 
-    //          ::= <prefix> <unqualified-name>
-    if (!PushComponent(getDerived().parseUnqualifiedName(State)))
+    if (SoFar == nullptr)
       return nullptr;
     Subs.push_back(SoFar);
+
+    // No longer used.
+    // <data-member-prefix> := <member source-name> [<template-args>] M
+    consumeIf('M');
   }
 
   if (SoFar == nullptr || Subs.empty())
@@ -3366,6 +3350,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseBaseUnresolvedName() {
 //                   ::= [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 "::"
+// [gs] has been parsed by caller.
 //                   ::= 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
@@ -3373,7 +3358,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseBaseUnresolvedName() {
 //
 // <unresolved-qualifier-level> ::= <simple-id>
 template <typename Derived, typename Alloc>
-Node *AbstractManglingParser<Derived, Alloc>::parseUnresolvedName() {
+Node *AbstractManglingParser<Derived, Alloc>::parseUnresolvedName(bool Global) {
   Node *SoFar = nullptr;
 
   // srN <unresolved-type> [<template-args>] <unresolved-qualifier-level>* E <base-unresolved-name>
@@ -3407,8 +3392,6 @@ Node *AbstractManglingParser<Derived, Alloc>::parseUnresolvedName() {
     return make<QualifiedName>(SoFar, Base);
   }
 
-  bool Global = consumeIf("gs");
-
   // [gs] <base-unresolved-name>                     # x or (with "gs") ::x
   if (!consumeIf("sr")) {
     SoFar = getDerived().parseBaseUnresolvedName();
@@ -3638,7 +3621,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseDecltype() {
     return nullptr;
   if (!consumeIf('E'))
     return nullptr;
-  return make<EnclosingExpr>("decltype(", E, ")");
+  return make<EnclosingExpr>("decltype", E);
 }
 
 // <array-type> ::= A <positive dimension number> _ <element type>
@@ -3724,8 +3707,8 @@ Node *AbstractManglingParser<Derived, Alloc>::parseQualifiedType() {
       StringView ProtoSourceName = Qual.dropFront(std::strlen("objcproto"));
       StringView Proto;
       {
-        SwapAndRestore<const char *> SaveFirst(First, ProtoSourceName.begin()),
-                                     SaveLast(Last, ProtoSourceName.end());
+        ScopedOverride<const char *> SaveFirst(First, ProtoSourceName.begin()),
+            SaveLast(Last, ProtoSourceName.end());
         Proto = parseBareSourceName();
       }
       if (Proto.empty())
@@ -3930,6 +3913,22 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
         return nullptr;
       return make<BinaryFPType>(DimensionNumber);
     }
+    //                ::= DB <number> _                             # C23 signed _BitInt(N)
+    //                ::= DB <instantiation-dependent expression> _ # C23 signed _BitInt(N)
+    //                ::= DU <number> _                             # C23 unsigned _BitInt(N)
+    //                ::= DU <instantiation-dependent expression> _ # C23 unsigned _BitInt(N)
+    case 'B':
+    case 'U': {
+      bool Signed = look(1) == 'B';
+      First += 2;
+      Node *Size = std::isdigit(look()) ? make<NameType>(parseNumber())
+                                        : getDerived().parseExpr();
+      if (!Size)
+        return nullptr;
+      if (!consumeIf('_'))
+        return nullptr;
+      return make<BitIntType>(Size, Signed);
+    }
     //                ::= Di   # char32_t
     case 'i':
       First += 2;
@@ -4078,8 +4077,9 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
   //             ::= <substitution>  # See Compression below
   case 'S': {
     if (look(1) != 't') {
-      Result = getDerived().parseSubstitution();
-      if (Result == nullptr)
+      bool IsSubst = false;
+      Result = getDerived().parseUnscopedName(nullptr, &IsSubst);
+      if (!Result)
         return nullptr;
 
       // Sub could be either of:
@@ -4092,12 +4092,14 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
       // If this is followed by some <template-args>, and we're permitted to
       // parse them, take the second production.
 
-      if (TryToParseTemplateArgs && look() == 'I') {
+      if (look() == 'I' && (!IsSubst || TryToParseTemplateArgs)) {
+        if (!IsSubst)
+          Subs.push_back(Result);
         Node *TA = getDerived().parseTemplateArgs();
         if (TA == nullptr)
           return nullptr;
         Result = make<NameWithTemplateArgs>(Result, TA);
-      } else {
+      } else if (IsSubst) {
         // If all we parsed was a substitution, don't re-insert into the
         // substitution table.
         return Result;
@@ -4122,22 +4124,24 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
 }
 
 template <typename Derived, typename Alloc>
-Node *AbstractManglingParser<Derived, Alloc>::parsePrefixExpr(StringView Kind) {
+Node *AbstractManglingParser<Derived, Alloc>::parsePrefixExpr(StringView Kind,
+                                                              Node::Prec Prec) {
   Node *E = getDerived().parseExpr();
   if (E == nullptr)
     return nullptr;
-  return make<PrefixExpr>(Kind, E);
+  return make<PrefixExpr>(Kind, E, Prec);
 }
 
 template <typename Derived, typename Alloc>
-Node *AbstractManglingParser<Derived, Alloc>::parseBinaryExpr(StringView Kind) {
+Node *AbstractManglingParser<Derived, Alloc>::parseBinaryExpr(StringView Kind,
+                                                              Node::Prec Prec) {
   Node *LHS = getDerived().parseExpr();
   if (LHS == nullptr)
     return nullptr;
   Node *RHS = getDerived().parseExpr();
   if (RHS == nullptr)
     return nullptr;
-  return make<BinaryExpr>(LHS, Kind, RHS);
+  return make<BinaryExpr>(LHS, Kind, RHS, Prec);
 }
 
 template <typename Derived, typename Alloc>
@@ -4192,43 +4196,6 @@ Node *AbstractManglingParser<Derived, Alloc>::parseFunctionParam() {
   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>
@@ -4237,7 +4204,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseConversionExpr() {
     return nullptr;
   Node *Ty;
   {
-    SwapAndRestore<bool> SaveTemp(TryToParseTemplateArgs, false);
+    ScopedOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
     Ty = getDerived().parseType();
   }
 
@@ -4354,7 +4321,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExprPrimary() {
     return nullptr;
   }
   case 'D':
-    if (consumeIf("DnE"))
+    if (consumeIf("Dn") && (consumeIf('0'), consumeIf('E')))
       return make<NameType>("nullptr");
     return nullptr;
   case 'T':
@@ -4441,55 +4408,38 @@ 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
+  bool IsLeftFold = false, HasInitializer = false;
+  switch (look()) {
+  default:
     return nullptr;
+  case 'L':
+    IsLeftFold = true;
+    HasInitializer = true;
+    break;
+  case 'R':
+    HasInitializer = true;
+    break;
+  case 'l':
+    IsLeftFold = true;
+    break;
+  case 'r':
+    break;
+  }
   ++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;
+  const auto *Op = parseOperatorEncoding();
+  if (!Op)
+    return nullptr;
+  if (!(Op->getKind() == OperatorInfo::Binary
+        || (Op->getKind() == OperatorInfo::Member
+            && Op->getName().back() == '*')))
+    return nullptr;
+
+  Node *Pack = getDerived().parseExpr();
   if (Pack == nullptr)
     return nullptr;
+
+  Node *Init = nullptr;
   if (HasInitializer) {
     Init = getDerived().parseExpr();
     if (Init == nullptr)
@@ -4499,14 +4449,16 @@ Node *AbstractManglingParser<Derived, Alloc>::parseFoldExpr() {
   if (IsLeftFold && Init)
     std::swap(Pack, Init);
 
-  return make<FoldExpr>(IsLeftFold, OperatorName, Pack, Init);
+  return make<FoldExpr>(IsLeftFold, Op->getSymbol(), Pack, Init);
 }
 
 // <expression> ::= mc <parameter type> <expr> [<offset number>] E
 //
 // Not yet in the spec: https://github.com/itanium-cxx-abi/cxx-abi/issues/47
 template <typename Derived, typename Alloc>
-Node *AbstractManglingParser<Derived, Alloc>::parsePointerToMemberConversionExpr() {
+Node *
+AbstractManglingParser<Derived, Alloc>::parsePointerToMemberConversionExpr(
+    Node::Prec Prec) {
   Node *Ty = getDerived().parseType();
   if (!Ty)
     return nullptr;
@@ -4516,7 +4468,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parsePointerToMemberConversionExpr
   StringView Offset = getDerived().parseNumber(true);
   if (!consumeIf('E'))
     return nullptr;
-  return make<PointerToMemberConversionExpr>(Ty, Expr, Offset);
+  return make<PointerToMemberConversionExpr>(Ty, Expr, Offset, Prec);
 }
 
 // <expression> ::= so <referent type> <expr> [<offset number>] <union-selector>* [p] E
@@ -4593,316 +4545,127 @@ Node *AbstractManglingParser<Derived, Alloc>::parseSubobjectExpr() {
 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;
+  const auto *Op = parseOperatorEncoding();
+  if (Op) {
+    auto Sym = Op->getSymbol();
+    switch (Op->getKind()) {
+    case OperatorInfo::Binary:
+      // Binary operator: lhs @ rhs
+      return getDerived().parseBinaryExpr(Sym, Op->getPrecedence());
+    case OperatorInfo::Prefix:
+      // Prefix unary operator: @ expr
+      return getDerived().parsePrefixExpr(Sym, Op->getPrecedence());
+    case OperatorInfo::Postfix: {
+      // Postfix unary operator: expr @
+      if (consumeIf('_'))
+        return getDerived().parsePrefixExpr(Sym, Op->getPrecedence());
       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);
+        return nullptr;
+      return make<PostfixExpr>(Ex, Sym, Op->getPrecedence());
     }
-    case 'n':
-      return getDerived().parseUnresolvedName();
-    case 's': {
-      First += 2;
-      Node *LHS = getDerived().parseExpr();
-      if (LHS == nullptr)
+    case OperatorInfo::Array: {
+      // Array Index:  lhs [ rhs ]
+      Node *Base = getDerived().parseExpr();
+      if (Base == nullptr)
         return nullptr;
-      Node *RHS = getDerived().parseExpr();
-      if (RHS == nullptr)
+      Node *Index = getDerived().parseExpr();
+      if (Index == nullptr)
         return nullptr;
-      return make<MemberExpr>(LHS, ".*", RHS);
+      return make<ArraySubscriptExpr>(Base, Index, Op->getPrecedence());
     }
-    case 't': {
-      First += 2;
+    case OperatorInfo::Member: {
+      // Member access lhs @ rhs
       Node *LHS = getDerived().parseExpr();
       if (LHS == nullptr)
-        return LHS;
+        return nullptr;
       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 make<MemberExpr>(LHS, Sym, RHS, Op->getPrecedence());
+    }
+    case OperatorInfo::New: {
+      // New
+      // # new (expr-list) type [(init)]
+      // [gs] nw <expression>* _ <type> [pi <expression>*] E
+      // # new[] (expr-list) type [(init)]
+      // [gs] na <expression>* _ <type> [pi <expression>*] E
+      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 nullptr;
-      Node *Index = getDerived().parseExpr();
-      if (Index == nullptr)
-        return Index;
-      return make<ArraySubscriptExpr>(Base, Index);
-    }
-    case 'l': {
-      First += 2;
+      bool HaveInits = consumeIf("pi");
       size_t InitsBegin = Names.size();
       while (!consumeIf('E')) {
-        Node *E = getDerived().parseBracedExpr();
-        if (E == nullptr)
+        if (!HaveInits)
           return nullptr;
-        Names.push_back(E);
+        Node *Init = getDerived().parseExpr();
+        if (Init == nullptr)
+          return Init;
+        Names.push_back(Init);
       }
-      return make<InitListExpr>(nullptr, popTrailingNodeArray(InitsBegin));
-    }
+      NodeArray Inits = popTrailingNodeArray(InitsBegin);
+      return make<NewExpr>(ExprList, Ty, Inits, Global,
+                           /*IsArray=*/Op->getFlag(), Op->getPrecedence());
     }
-    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 'c':
-      First += 2;
-      return parsePointerToMemberConversionExpr();
-    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("--");
+    case OperatorInfo::Del: {
+      // Delete
       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 make<DeleteExpr>(Ex, Global, /*IsArray=*/Op->getFlag(),
+                              Op->getPrecedence());
     }
-    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 OperatorInfo::Call: {
+      // Function Call
+      Node *Callee = getDerived().parseExpr();
+      if (Callee == nullptr)
+        return nullptr;
+      size_t ExprsBegin = Names.size();
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseExpr();
+        if (E == nullptr)
+          return nullptr;
+        Names.push_back(E);
+      }
+      return make<CallExpr>(Callee, popTrailingNodeArray(ExprsBegin),
+                            Op->getPrecedence());
     }
-    case 's':
-      First += 2;
-      return getDerived().parsePrefixExpr("+");
-    case 't': {
-      First += 2;
-      Node *L = getDerived().parseExpr();
-      if (L == nullptr)
+    case OperatorInfo::CCast: {
+      // C Cast: (type)expr
+      Node *Ty;
+      {
+        ScopedOverride<bool> SaveTemp(TryToParseTemplateArgs, false);
+        Ty = getDerived().parseType();
+      }
+      if (Ty == nullptr)
         return nullptr;
-      Node *R = getDerived().parseExpr();
-      if (R == nullptr)
+
+      size_t ExprsBegin = Names.size();
+      bool IsMany = consumeIf('_');
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseExpr();
+        if (E == nullptr)
+          return E;
+        Names.push_back(E);
+        if (!IsMany)
+          break;
+      }
+      NodeArray Exprs = popTrailingNodeArray(ExprsBegin);
+      if (!IsMany && Exprs.size() != 1)
         return nullptr;
-      return make<MemberExpr>(L, "->", R);
+      return make<ConversionExpr>(Ty, Exprs, Op->getPrecedence());
     }
-    }
-    return nullptr;
-  case 'q':
-    if (First[1] == 'u') {
-      First += 2;
+    case OperatorInfo::Conditional: {
+      // Conditional operator: expr ? expr : expr
       Node *Cond = getDerived().parseExpr();
       if (Cond == nullptr)
         return nullptr;
@@ -4912,147 +4675,120 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
       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);
+      return make<ConditionalExpr>(Cond, LHS, RHS, Op->getPrecedence());
     }
-    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 'o':
-      First += 2;
-      return parseSubobjectExpr();
-    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;
+    case OperatorInfo::NamedCast: {
+      // Named cast operation, @<type>(expr)
       Node *Ty = getDerived().parseType();
       if (Ty == nullptr)
-        return Ty;
-      return make<EnclosingExpr>("sizeof (", Ty, ")");
-    }
-    case 'z': {
-      First += 2;
+        return nullptr;
       Node *Ex = getDerived().parseExpr();
       if (Ex == nullptr)
-        return Ex;
-      return make<EnclosingExpr>("sizeof (", Ex, ")");
+        return nullptr;
+      return make<CastExpr>(Sym, Ty, Ex, Op->getPrecedence());
     }
-    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)
+    case OperatorInfo::OfIdOp: {
+      // [sizeof/alignof/typeid] ( <type>|<expr> )
+      Node *Arg =
+          Op->getFlag() ? getDerived().parseType() : getDerived().parseExpr();
+      if (!Arg)
         return nullptr;
-      return make<EnclosingExpr>("sizeof... (", Pack, ")");
+      return make<EnclosingExpr>(Sym, Arg, Op->getPrecedence());
     }
+    case OperatorInfo::NameOnly: {
+      // Not valid as an expression operand.
+      return nullptr;
     }
-    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, ")");
+    DEMANGLE_UNREACHABLE;
+  }
+
+  if (numLeft() < 2)
+    return nullptr;
+
+  if (look() == 'L')
+    return getDerived().parseExprPrimary();
+  if (look() == 'T')
+    return getDerived().parseTemplateParam();
+  if (look() == '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();
+  }
+  if (consumeIf("il")) {
+    size_t InitsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *E = getDerived().parseBracedExpr();
+      if (E == nullptr)
+        return nullptr;
+      Names.push_back(E);
     }
-    case 'l': {
-      First += 2;
-      Node *Ty = getDerived().parseType();
-      if (Ty == nullptr)
+    return make<InitListExpr>(nullptr, popTrailingNodeArray(InitsBegin));
+  }
+  if (consumeIf("mc"))
+    return parsePointerToMemberConversionExpr(Node::Prec::Unary);
+  if (consumeIf("nx")) {
+    Node *Ex = getDerived().parseExpr();
+    if (Ex == nullptr)
+      return Ex;
+    return make<EnclosingExpr>("noexcept ", Ex, Node::Prec::Unary);
+  }
+  if (consumeIf("so"))
+    return parseSubobjectExpr();
+  if (consumeIf("sp")) {
+    Node *Child = getDerived().parseExpr();
+    if (Child == nullptr)
+      return nullptr;
+    return make<ParameterPackExpansion>(Child);
+  }
+  if (consumeIf("sZ")) {
+    if (look() == 'T') {
+      Node *R = getDerived().parseTemplateParam();
+      if (R == 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));
+      return make<SizeofParamPackExpr>(R);
     }
-    case 'r':
-      First += 2;
-      return make<NameType>("throw");
-    case 'w': {
-      First += 2;
-      Node *Ex = getDerived().parseExpr();
-      if (Ex == nullptr)
+    Node *FP = getDerived().parseFunctionParam();
+    if (FP == nullptr)
+      return nullptr;
+    return make<EnclosingExpr>("sizeof... ", FP);
+  }
+  if (consumeIf("sP")) {
+    size_t ArgsBegin = Names.size();
+    while (!consumeIf('E')) {
+      Node *Arg = getDerived().parseTemplateArg();
+      if (Arg == nullptr)
         return nullptr;
-      return make<ThrowExpr>(Ex);
+      Names.push_back(Arg);
     }
+    auto *Pack = make<NodeArrayNode>(popTrailingNodeArray(ArgsBegin));
+    if (!Pack)
+      return nullptr;
+    return make<EnclosingExpr>("sizeof... ", Pack);
+  }
+  if (consumeIf("tl")) {
+    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 nullptr;
-  case 'u': {
-    ++First;
+    return make<InitListExpr>(Ty, popTrailingNodeArray(InitsBegin));
+  }
+  if (consumeIf("tr"))
+    return make<NameType>("throw");
+  if (consumeIf("tw")) {
+    Node *Ex = getDerived().parseExpr();
+    if (Ex == nullptr)
+      return nullptr;
+    return make<ThrowExpr>(Ex);
+  }
+  if (consumeIf('u')) {
     Node *Name = getDerived().parseSourceName(/*NameState=*/nullptr);
     if (!Name)
       return nullptr;
@@ -5061,45 +4797,36 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
     // interpreted as <type> node 'short' or 'ellipsis'. However, neither
     // __uuidof(short) nor __uuidof(...) can actually appear, so there is no
     // actual conflict here.
+    bool IsUUID = false;
+    Node *UUID = nullptr;
     if (Name->getBaseName() == "__uuidof") {
-      if (numLeft() < 2)
-        return nullptr;
-      if (*First == 't') {
-        ++First;
-        Node *Ty = getDerived().parseType();
-        if (!Ty)
-          return nullptr;
-        return make<CallExpr>(Name, makeNodeArray(&Ty, &Ty + 1));
-      }
-      if (*First == 'z') {
-        ++First;
-        Node *Ex = getDerived().parseExpr();
-        if (!Ex)
-          return nullptr;
-        return make<CallExpr>(Name, makeNodeArray(&Ex, &Ex + 1));
+      if (consumeIf('t')) {
+        UUID = getDerived().parseType();
+        IsUUID = true;
+      } else if (consumeIf('z')) {
+        UUID = getDerived().parseExpr();
+        IsUUID = true;
       }
     }
     size_t ExprsBegin = Names.size();
-    while (!consumeIf('E')) {
-      Node *E = getDerived().parseTemplateArg();
-      if (E == nullptr)
-        return E;
-      Names.push_back(E);
+    if (IsUUID) {
+      if (UUID == nullptr)
+        return nullptr;
+      Names.push_back(UUID);
+    } else {
+      while (!consumeIf('E')) {
+        Node *E = getDerived().parseTemplateArg();
+        if (E == nullptr)
+          return E;
+        Names.push_back(E);
+      }
     }
-    return make<CallExpr>(Name, popTrailingNodeArray(ExprsBegin));
-  }
-  case '1':
-  case '2':
-  case '3':
-  case '4':
-  case '5':
-  case '6':
-  case '7':
-  case '8':
-  case '9':
-    return getDerived().parseUnresolvedName();
+    return make<CallExpr>(Name, popTrailingNodeArray(ExprsBegin),
+                          Node::Prec::Postfix);
   }
-  return nullptr;
+
+  // Only unresolved names remain.
+  return getDerived().parseUnresolvedName(Global);
 }
 
 // <call-offset> ::= h <nv-offset> _
@@ -5132,14 +4859,17 @@ bool AbstractManglingParser<Alloc, Derived>::parseCallOffset() {
 //                    # 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
+//                # Guard variable for one-time initialization
+//                ::= GV <object name>
 //                                     # 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
+//                # construction vtable for second-in-first
+//      extension ::= TC <first type> <number> _ <second type>
 //      extension ::= GR <object name> # reference temporary for object
+//      extension ::= GI <module name> # module global initializer
 template <typename Derived, typename Alloc>
 Node *AbstractManglingParser<Derived, Alloc>::parseSpecialName() {
   switch (look()) {
@@ -5266,6 +4996,16 @@ Node *AbstractManglingParser<Derived, Alloc>::parseSpecialName() {
         return nullptr;
       return make<SpecialName>("reference temporary for ", Name);
     }
+    // GI <module-name> v
+    case 'I': {
+      First += 2;
+      ModuleName *Module = nullptr;
+      if (getDerived().parseModuleNameOpt(Module))
+        return nullptr;
+      if (Module == nullptr)
+        return nullptr;
+      return make<SpecialName>("initializer for module ", Module);
+    }
     }
   }
   return nullptr;
@@ -5380,7 +5120,7 @@ template <>
 struct FloatData<long double>
 {
 #if defined(__mips__) && defined(__mips_n64) || defined(__aarch64__) || \
-    defined(__wasm__)
+    defined(__wasm__) || defined(__riscv) || defined(__loongarch__)
     static const size_t mangled_size = 32;
 #elif defined(__arm__) || defined(__mips__) || defined(__hexagon__)
     static const size_t mangled_size = 16;
@@ -5445,6 +5185,7 @@ bool AbstractManglingParser<Alloc, Derived>::parseSeqId(size_t *Out) {
 // <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> >
+// The St case is handled specially in parseNestedName.
 template <typename Derived, typename Alloc>
 Node *AbstractManglingParser<Derived, Alloc>::parseSubstitution() {
   if (!consumeIf('S'))
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumNodes.def b/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumNodes.def
new file mode 100644
index 0000000000..f615cb9fad
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxxabi/src/demangle/ItaniumNodes.def
@@ -0,0 +1,95 @@
+//===------------------------- ItaniumNodes.def ----------------*- 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-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Define the demangler's node names
+
+#ifndef NODE
+#error Define NODE to handle nodes
+#endif
+
+NODE(NodeArrayNode)
+NODE(DotSuffix)
+NODE(VendorExtQualType)
+NODE(QualType)
+NODE(ConversionOperatorType)
+NODE(PostfixQualifiedType)
+NODE(ElaboratedTypeSpefType)
+NODE(NameType)
+NODE(AbiTagAttr)
+NODE(EnableIfAttr)
+NODE(ObjCProtoName)
+NODE(PointerType)
+NODE(ReferenceType)
+NODE(PointerToMemberType)
+NODE(ArrayType)
+NODE(FunctionType)
+NODE(NoexceptSpec)
+NODE(DynamicExceptionSpec)
+NODE(FunctionEncoding)
+NODE(LiteralOperator)
+NODE(SpecialName)
+NODE(CtorVtableSpecialName)
+NODE(QualifiedName)
+NODE(NestedName)
+NODE(LocalName)
+NODE(ModuleName)
+NODE(ModuleEntity)
+NODE(VectorType)
+NODE(PixelVectorType)
+NODE(BinaryFPType)
+NODE(BitIntType)
+NODE(SyntheticTemplateParamName)
+NODE(TypeTemplateParamDecl)
+NODE(NonTypeTemplateParamDecl)
+NODE(TemplateTemplateParamDecl)
+NODE(TemplateParamPackDecl)
+NODE(ParameterPack)
+NODE(TemplateArgumentPack)
+NODE(ParameterPackExpansion)
+NODE(TemplateArgs)
+NODE(ForwardTemplateReference)
+NODE(NameWithTemplateArgs)
+NODE(GlobalQualifiedName)
+NODE(ExpandedSpecialSubstitution)
+NODE(SpecialSubstitution)
+NODE(CtorDtorName)
+NODE(DtorName)
+NODE(UnnamedTypeName)
+NODE(ClosureTypeName)
+NODE(StructuredBindingName)
+NODE(BinaryExpr)
+NODE(ArraySubscriptExpr)
+NODE(PostfixExpr)
+NODE(ConditionalExpr)
+NODE(MemberExpr)
+NODE(SubobjectExpr)
+NODE(EnclosingExpr)
+NODE(CastExpr)
+NODE(SizeofParamPackExpr)
+NODE(CallExpr)
+NODE(NewExpr)
+NODE(DeleteExpr)
+NODE(PrefixExpr)
+NODE(FunctionParam)
+NODE(ConversionExpr)
+NODE(PointerToMemberConversionExpr)
+NODE(InitListExpr)
+NODE(FoldExpr)
+NODE(ThrowExpr)
+NODE(BoolExpr)
+NODE(StringLiteral)
+NODE(LambdaExpr)
+NODE(EnumLiteral)
+NODE(IntegerLiteral)
+NODE(FloatLiteral)
+NODE(DoubleLiteral)
+NODE(LongDoubleLiteral)
+NODE(BracedExpr)
+NODE(BracedRangeExpr)
+
+#undef NODE
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/demangle/Utility.h b/contrib/libs/cxxsupp/libcxxabi/src/demangle/Utility.h
index 3b27328522..c9b211b544 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/demangle/Utility.h
+++ b/contrib/libs/cxxsupp/libcxxabi/src/demangle/Utility.h
@@ -33,61 +33,78 @@ class OutputBuffer {
   size_t CurrentPosition = 0;
   size_t BufferCapacity = 0;
 
-  // Ensure there is at least n more positions in buffer.
+  // Ensure there are at least N more positions in the buffer.
   void grow(size_t N) {
-    if (N + CurrentPosition >= BufferCapacity) {
+    size_t Need = N + CurrentPosition;
+    if (Need > BufferCapacity) {
+      // Reduce the number of reallocations, with a bit of hysteresis. The
+      // number here is chosen so the first allocation will more-than-likely not
+      // allocate more than 1K.
+      Need += 1024 - 32;
       BufferCapacity *= 2;
-      if (BufferCapacity < N + CurrentPosition)
-        BufferCapacity = N + CurrentPosition;
+      if (BufferCapacity < Need)
+        BufferCapacity = Need;
       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;
-    }
-
+  OutputBuffer &writeUnsigned(uint64_t N, bool isNeg = false) {
     std::array<char, 21> Temp;
     char *TempPtr = Temp.data() + Temp.size();
 
-    while (N) {
+    // Output at least one character.
+    do {
       *--TempPtr = char('0' + N % 10);
       N /= 10;
-    }
+    } while (N);
 
-    // Add negative sign...
+    // Add negative sign.
     if (isNeg)
       *--TempPtr = '-';
-    this->operator<<(StringView(TempPtr, Temp.data() + Temp.size()));
+
+    return operator+=(StringView(TempPtr, Temp.data() + Temp.size()));
   }
 
 public:
   OutputBuffer(char *StartBuf, size_t Size)
-      : Buffer(StartBuf), CurrentPosition(0), BufferCapacity(Size) {}
+      : Buffer(StartBuf), BufferCapacity(Size) {}
+  OutputBuffer(char *StartBuf, size_t *SizePtr)
+      : OutputBuffer(StartBuf, StartBuf ? *SizePtr : 0) {}
   OutputBuffer() = default;
-  void reset(char *Buffer_, size_t BufferCapacity_) {
-    CurrentPosition = 0;
-    Buffer = Buffer_;
-    BufferCapacity = BufferCapacity_;
-  }
+  // Non-copyable
+  OutputBuffer(const OutputBuffer &) = delete;
+  OutputBuffer &operator=(const OutputBuffer &) = delete;
+
+  operator StringView() const { return StringView(Buffer, CurrentPosition); }
 
   /// 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();
 
+  /// When zero, we're printing template args and '>' needs to be parenthesized.
+  /// Use a counter so we can simply increment inside parentheses.
+  unsigned GtIsGt = 1;
+
+  bool isGtInsideTemplateArgs() const { return GtIsGt == 0; }
+
+  void printOpen(char Open = '(') {
+    GtIsGt++;
+    *this += Open;
+  }
+  void printClose(char Close = ')') {
+    GtIsGt--;
+    *this += Close;
+  }
+
   OutputBuffer &operator+=(StringView R) {
-    size_t Size = R.size();
-    if (Size == 0)
-      return *this;
-    grow(Size);
-    std::memmove(Buffer + CurrentPosition, R.begin(), Size);
-    CurrentPosition += Size;
+    if (size_t Size = R.size()) {
+      grow(Size);
+      std::memcpy(Buffer + CurrentPosition, R.begin(), Size);
+      CurrentPosition += Size;
+    }
     return *this;
   }
 
@@ -97,9 +114,7 @@ public:
     return *this;
   }
 
-  OutputBuffer &operator<<(StringView R) { return (*this += R); }
-
-  OutputBuffer prepend(StringView R) {
+  OutputBuffer &prepend(StringView R) {
     size_t Size = R.size();
 
     grow(Size);
@@ -110,19 +125,16 @@ public:
     return *this;
   }
 
+  OutputBuffer &operator<<(StringView R) { return (*this += R); }
+
   OutputBuffer &operator<<(char C) { return (*this += C); }
 
   OutputBuffer &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;
+    return writeUnsigned(static_cast<unsigned long long>(std::abs(N)), N < 0);
   }
 
   OutputBuffer &operator<<(unsigned long long N) {
-    writeUnsigned(N, false);
-    return *this;
+    return writeUnsigned(N, false);
   }
 
   OutputBuffer &operator<<(long N) {
@@ -155,7 +167,8 @@ public:
   void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; }
 
   char back() const {
-    return CurrentPosition ? Buffer[CurrentPosition - 1] : '\0';
+    assert(CurrentPosition);
+    return Buffer[CurrentPosition - 1];
   }
 
   bool empty() const { return CurrentPosition == 0; }
@@ -165,52 +178,22 @@ public:
   size_t getBufferCapacity() const { return BufferCapacity; }
 };
 
-template <class T> class SwapAndRestore {
-  T &Restore;
-  T OriginalValue;
-  bool ShouldRestore = true;
+template <class T> class ScopedOverride {
+  T &Loc;
+  T Original;
 
 public:
-  SwapAndRestore(T &Restore_) : SwapAndRestore(Restore_, Restore_) {}
+  ScopedOverride(T &Loc_) : ScopedOverride(Loc_, Loc_) {}
 
-  SwapAndRestore(T &Restore_, T NewVal)
-      : Restore(Restore_), OriginalValue(Restore) {
-    Restore = std::move(NewVal);
+  ScopedOverride(T &Loc_, T NewVal) : Loc(Loc_), Original(Loc_) {
+    Loc_ = std::move(NewVal);
   }
-  ~SwapAndRestore() {
-    if (ShouldRestore)
-      Restore = std::move(OriginalValue);
-  }
-
-  void shouldRestore(bool ShouldRestore_) { ShouldRestore = ShouldRestore_; }
-
-  void restoreNow(bool Force) {
-    if (!Force && !ShouldRestore)
-      return;
+  ~ScopedOverride() { Loc = std::move(Original); }
 
-    Restore = std::move(OriginalValue);
-    ShouldRestore = false;
-  }
-
-  SwapAndRestore(const SwapAndRestore &) = delete;
-  SwapAndRestore &operator=(const SwapAndRestore &) = delete;
+  ScopedOverride(const ScopedOverride &) = delete;
+  ScopedOverride &operator=(const ScopedOverride &) = delete;
 };
 
-inline bool initializeOutputBuffer(char *Buf, size_t *N, OutputBuffer &OB,
-                                   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;
-
-  OB.reset(Buf, BufferSize);
-  return true;
-}
-
 DEMANGLE_NAMESPACE_END
 
 #endif
diff --git a/contrib/libs/cxxsupp/libcxxabi/src/fallback_malloc.cpp b/contrib/libs/cxxsupp/libcxxabi/src/fallback_malloc.cpp
index 0443fd9e62..1ea2a4eb6c 100644
--- a/contrib/libs/cxxsupp/libcxxabi/src/fallback_malloc.cpp
+++ b/contrib/libs/cxxsupp/libcxxabi/src/fallback_malloc.cpp
@@ -19,6 +19,7 @@
 #include <__memory/aligned_alloc.h>
 #endif
 
+#include <assert.h>
 #include <stdlib.h> // for malloc, calloc, free
 #include <string.h> // for memset
 #include <new> // for std::__libcpp_aligned_{alloc,free}
@@ -37,10 +38,9 @@ namespace {
 
 // When POSIX threads are not available, make the mutex operations a nop
 #ifndef _LIBCXXABI_HAS_NO_THREADS
-_LIBCPP_SAFE_STATIC
-static std::__libcpp_mutex_t heap_mutex = _LIBCPP_MUTEX_INITIALIZER;
+static _LIBCPP_CONSTINIT std::__libcpp_mutex_t heap_mutex = _LIBCPP_MUTEX_INITIALIZER;
 #else
-static void* heap_mutex = 0;
+static _LIBCPP_CONSTINIT void* heap_mutex = 0;
 #endif
 
 class mutexor {
@@ -68,11 +68,28 @@ char heap[HEAP_SIZE] __attribute__((aligned));
 typedef unsigned short heap_offset;
 typedef unsigned short heap_size;
 
+// On both 64 and 32 bit targets heap_node should have the following properties
+// Size: 4
+// Alignment: 2
 struct heap_node {
   heap_offset next_node; // offset into heap
   heap_size len;         // size in units of "sizeof(heap_node)"
 };
 
+// All pointers returned by fallback_malloc must be at least aligned
+// as RequiredAligned. Note that RequiredAlignment can be greater than
+// alignof(std::max_align_t) on 64 bit systems compiling 32 bit code.
+struct FallbackMaxAlignType {
+} __attribute__((aligned));
+const size_t RequiredAlignment = alignof(FallbackMaxAlignType);
+
+static_assert(alignof(FallbackMaxAlignType) % sizeof(heap_node) == 0,
+              "The required alignment must be evenly divisible by the sizeof(heap_node)");
+
+// The number of heap_node's that can fit in a chunk of memory with the size
+// of the RequiredAlignment. On 64 bit targets NodesPerAlignment should be 4.
+const size_t NodesPerAlignment = alignof(FallbackMaxAlignType) / sizeof(heap_node);
+
 static const heap_node* list_end =
     (heap_node*)(&heap[HEAP_SIZE]); // one past the end of the heap
 static heap_node* freelist = NULL;
@@ -87,10 +104,23 @@ heap_offset offset_from_node(const heap_node* ptr) {
       sizeof(heap_node));
 }
 
+// Return a pointer to the first address, 'A', in `heap` that can actually be
+// used to represent a heap_node. 'A' must be aligned so that
+// '(A + sizeof(heap_node)) % RequiredAlignment == 0'. On 64 bit systems this
+// address should be 12 bytes after the first 16 byte boundary.
+heap_node* getFirstAlignedNodeInHeap() {
+  heap_node* node = (heap_node*)heap;
+  const size_t alignNBytesAfterBoundary = RequiredAlignment - sizeof(heap_node);
+  size_t boundaryOffset = reinterpret_cast<size_t>(node) % RequiredAlignment;
+  size_t requiredOffset = alignNBytesAfterBoundary - boundaryOffset;
+  size_t NElemOffset = requiredOffset / sizeof(heap_node);
+  return node + NElemOffset;
+}
+
 void init_heap() {
-  freelist = (heap_node*)heap;
+  freelist = getFirstAlignedNodeInHeap();
   freelist->next_node = offset_from_node(list_end);
-  freelist->len = HEAP_SIZE / sizeof(heap_node);
+  freelist->len = static_cast<heap_size>(list_end - freelist);
 }
 
 //  How big a chunk we allocate
@@ -114,23 +144,44 @@ void* fallback_malloc(size_t len) {
   for (p = freelist, prev = 0; p && p != list_end;
        prev = p, p = node_from_offset(p->next_node)) {
 
-    if (p->len > nelems) { //  chunk is larger, shorten, and return the tail
-      heap_node* q;
+    // Check the invariant that all heap_nodes pointers 'p' are aligned
+    // so that 'p + 1' has an alignment of at least RequiredAlignment
+    assert(reinterpret_cast<size_t>(p + 1) % RequiredAlignment == 0);
+
+    // Calculate the number of extra padding elements needed in order
+    // to split 'p' and create a properly aligned heap_node from the tail
+    // of 'p'. We calculate aligned_nelems such that 'p->len - aligned_nelems'
+    // will be a multiple of NodesPerAlignment.
+    size_t aligned_nelems = nelems;
+    if (p->len > nelems) {
+      heap_size remaining_len = static_cast<heap_size>(p->len - nelems);
+      aligned_nelems += remaining_len % NodesPerAlignment;
+    }
 
-      p->len = static_cast<heap_size>(p->len - nelems);
+    // chunk is larger and we can create a properly aligned heap_node
+    // from the tail. In this case we shorten 'p' and return the tail.
+    if (p->len > aligned_nelems) {
+      heap_node* q;
+      p->len = static_cast<heap_size>(p->len - aligned_nelems);
       q = p + p->len;
       q->next_node = 0;
-      q->len = static_cast<heap_size>(nelems);
-      return (void*)(q + 1);
+      q->len = static_cast<heap_size>(aligned_nelems);
+      void* ptr = q + 1;
+      assert(reinterpret_cast<size_t>(ptr) % RequiredAlignment == 0);
+      return ptr;
     }
 
-    if (p->len == nelems) { // exact size match
+    // The chunk is the exact size or the chunk is larger but not large
+    // enough to split due to alignment constraints.
+    if (p->len >= nelems) {
       if (prev == 0)
         freelist = node_from_offset(p->next_node);
       else
         prev->next_node = p->next_node;
       p->next_node = 0;
-      return (void*)(p + 1);
+      void* ptr = p + 1;
+      assert(reinterpret_cast<size_t>(ptr) % RequiredAlignment == 0);
+      return ptr;
     }
   }
   return NULL; // couldn't find a spot big enough
diff --git a/contrib/libs/cxxsupp/libcxxabi/ya.make b/contrib/libs/cxxsupp/libcxxabi/ya.make
index 1f739ea96f..2dace23170 100644
--- a/contrib/libs/cxxsupp/libcxxabi/ya.make
+++ b/contrib/libs/cxxsupp/libcxxabi/ya.make
@@ -11,9 +11,9 @@ LICENSE(
 
 LICENSE_TEXTS(.yandex_meta/licenses.list.txt)
 
-VERSION(14.0.6)
+VERSION(16.0.6)
 
-ORIGINAL_SOURCE(https://github.com/llvm/llvm-project/archive/llvmorg-14.0.6.tar.gz)
+ORIGINAL_SOURCE(https://github.com/llvm/llvm-project/archive/llvmorg-16.0.6.tar.gz)
 
 PEERDIR(
     library/cpp/sanitizer/include
diff --git a/util/system/type_name_ut.cpp b/util/system/type_name_ut.cpp
index 86597f4232..c9b2a1e775 100644
--- a/util/system/type_name_ut.cpp
+++ b/util/system/type_name_ut.cpp
@@ -67,10 +67,10 @@ Y_UNIT_TEST_SUITE(TypeName) {
         UNIT_ASSERT_VALUES_EQUAL(TypeName<double>(), "double");
 
 #ifdef _MSC_VER
-        UNIT_ASSERT_VALUES_EQUAL(TypeName<std::string>(), "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName<std::string>(), "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char>>");
         UNIT_ASSERT_VALUES_EQUAL(TypeName<std::runtime_error>(), "class std::runtime_error");
 #else
-        UNIT_ASSERT_VALUES_EQUAL(TypeName<std::string>(), "std::basic_string<char, std::char_traits<char>, std::allocator<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName<std::string>(), "std::basic_string<char, std::char_traits<char>, std::allocator<char>>");
         UNIT_ASSERT_VALUES_EQUAL(TypeName<std::runtime_error>(), "std::runtime_error");
 #endif
     }
@@ -78,10 +78,10 @@ Y_UNIT_TEST_SUITE(TypeName) {
     Y_UNIT_TEST(FromArcadiaTypes) {
 #ifdef _MSC_VER
         UNIT_ASSERT_VALUES_EQUAL(TypeName<yexception>(), "class yexception");
-        UNIT_ASSERT_VALUES_EQUAL(TypeName<TString>(), "class TBasicString<char,struct std::char_traits<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName<TString>(), "class TBasicString<char,struct std::char_traits<char>>");
 #else
         UNIT_ASSERT_VALUES_EQUAL(TypeName<yexception>(), "yexception");
-        UNIT_ASSERT_VALUES_EQUAL(TypeName<TString>(), "TBasicString<char, std::char_traits<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName<TString>(), "TBasicString<char, std::char_traits<char>>");
 #endif
     }
 
@@ -122,10 +122,10 @@ Y_UNIT_TEST_SUITE(TypeName) {
         std::string string;
         std::runtime_error err("This is awful");
 #ifdef _MSC_VER
-        UNIT_ASSERT_VALUES_EQUAL(TypeName(string), "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName(string), "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char>>");
         UNIT_ASSERT_VALUES_EQUAL(TypeName(err), "class std::runtime_error");
 #else
-        UNIT_ASSERT_VALUES_EQUAL(TypeName(string), "std::basic_string<char, std::char_traits<char>, std::allocator<char> >");
+        UNIT_ASSERT_VALUES_EQUAL(TypeName(string), "std::basic_string<char, std::char_traits<char>, std::allocator<char>>");
         UNIT_ASSERT_VALUES_EQUAL(TypeName(err), "std::runtime_error");
 #endif
     }
diff --git a/util/system/ut/ya.make b/util/system/ut/ya.make
index f69ca701e5..b6c0512caa 100644
--- a/util/system/ut/ya.make
+++ b/util/system/ut/ya.make
@@ -71,12 +71,17 @@ SRCS(
     system/thread_ut.cpp
     system/tls_ut.cpp
     system/types_ut.cpp
-    system/type_name_ut.cpp
     system/user_ut.cpp
     system/unaligned_mem_ut.cpp
     system/yassert_ut.cpp
 )
 
+IF (NOT USE_STL_SYSTEM)
+    SRCS(
+        system/type_name_ut.cpp
+    )
+ENDIF()
+
 IF (OS_WINDOWS)
     SRCS(
         system/fs_win_ut.cpp