400 lines
12 KiB
C++
400 lines
12 KiB
C++
// -*- C++ -*- Exception handling and frame unwind runtime interface routines.
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// Copyright (C) 2001-2021 Free Software Foundation, Inc.
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//
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// This file is part of GCC.
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//
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// GCC is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// GCC is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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// This is derived from the C++ ABI for IA-64. Where we diverge
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// for cross-architecture compatibility are noted with "@@@".
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#ifndef _UNWIND_CXX_H
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#define _UNWIND_CXX_H 1
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// Level 2: C++ ABI
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#include <typeinfo>
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#include <exception>
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#include <cstddef>
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#include "unwind.h"
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#include <bits/atomic_word.h>
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#include <cxxabi.h>
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#ifdef _GLIBCXX_HAVE_SYS_SDT_H
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#include <sys/sdt.h>
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/* We only want to use stap probes starting with v3. Earlier versions
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added too much startup cost. */
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#if defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3
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#define PROBE2(name, arg1, arg2) STAP_PROBE2 (libstdcxx, name, arg1, arg2)
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#endif
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#endif
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#ifndef PROBE2
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#define PROBE2(name, arg1, arg2)
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#endif
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#pragma GCC visibility push(default)
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namespace __cxxabiv1
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{
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// A primary C++ exception object consists of a header, which is a wrapper
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// around an unwind object header with additional C++ specific information,
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// followed by the exception object itself.
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struct __cxa_exception
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{
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// Manage the exception object itself.
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std::type_info *exceptionType;
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void (_GLIBCXX_CDTOR_CALLABI *exceptionDestructor)(void *);
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// The C++ standard has entertaining rules wrt calling set_terminate
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// and set_unexpected in the middle of the exception cleanup process.
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std::unexpected_handler unexpectedHandler;
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std::terminate_handler terminateHandler;
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// The caught exception stack threads through here.
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__cxa_exception *nextException;
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// How many nested handlers have caught this exception. A negated
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// value is a signal that this object has been rethrown.
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int handlerCount;
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#ifdef __ARM_EABI_UNWINDER__
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// Stack of exceptions in cleanups.
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__cxa_exception* nextPropagatingException;
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// The number of active cleanup handlers for this exception.
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int propagationCount;
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#else
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// Cache parsed handler data from the personality routine Phase 1
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// for Phase 2 and __cxa_call_unexpected.
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int handlerSwitchValue;
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const unsigned char *actionRecord;
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const unsigned char *languageSpecificData;
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_Unwind_Ptr catchTemp;
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void *adjustedPtr;
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#endif
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// The generic exception header. Must be last.
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_Unwind_Exception unwindHeader;
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};
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struct __cxa_refcounted_exception
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{
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// Manage this header.
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_Atomic_word referenceCount;
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// __cxa_exception must be last, and no padding can be after it.
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__cxa_exception exc;
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};
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// A dependent C++ exception object consists of a wrapper around an unwind
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// object header with additional C++ specific information, containing a pointer
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// to a primary exception object.
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struct __cxa_dependent_exception
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{
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// The primary exception this thing depends on.
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void *primaryException;
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// Unused member to get similar layout to __cxa_exception, otherwise the
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// alignment requirements of _Unwind_Exception would require padding bytes
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// before the unwindHeader member.
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void (_GLIBCXX_CDTOR_CALLABI *__padding)(void *);
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// The C++ standard has entertaining rules wrt calling set_terminate
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// and set_unexpected in the middle of the exception cleanup process.
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std::unexpected_handler unexpectedHandler;
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std::terminate_handler terminateHandler;
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// The caught exception stack threads through here.
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__cxa_exception *nextException;
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// How many nested handlers have caught this exception. A negated
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// value is a signal that this object has been rethrown.
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int handlerCount;
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#ifdef __ARM_EABI_UNWINDER__
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// Stack of exceptions in cleanups.
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__cxa_exception* nextPropagatingException;
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// The number of active cleanup handlers for this exception.
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int propagationCount;
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#else
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// Cache parsed handler data from the personality routine Phase 1
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// for Phase 2 and __cxa_call_unexpected.
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int handlerSwitchValue;
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const unsigned char *actionRecord;
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const unsigned char *languageSpecificData;
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_Unwind_Ptr catchTemp;
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void *adjustedPtr;
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#endif
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// The generic exception header. Must be last.
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_Unwind_Exception unwindHeader;
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};
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// Each thread in a C++ program has access to a __cxa_eh_globals object.
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struct __cxa_eh_globals
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{
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__cxa_exception *caughtExceptions;
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unsigned int uncaughtExceptions;
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#ifdef __ARM_EABI_UNWINDER__
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__cxa_exception* propagatingExceptions;
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#endif
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};
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// @@@ These are not directly specified by the IA-64 C++ ABI.
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// Handles re-checking the exception specification if unexpectedHandler
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// throws, and if bad_exception needs to be thrown. Called from the
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// compiler.
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extern "C" void __cxa_call_unexpected (void *) __attribute__((__noreturn__));
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extern "C" void __cxa_call_terminate (_Unwind_Exception*) throw ()
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__attribute__((__noreturn__));
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#ifdef __ARM_EABI_UNWINDER__
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// Arm EABI specified routines.
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typedef enum {
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ctm_failed = 0,
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ctm_succeeded = 1,
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ctm_succeeded_with_ptr_to_base = 2
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} __cxa_type_match_result;
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extern "C" __cxa_type_match_result __cxa_type_match(_Unwind_Exception*,
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const std::type_info*,
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bool, void**);
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extern "C" bool __cxa_begin_cleanup (_Unwind_Exception*);
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extern "C" void __cxa_end_cleanup (void);
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#endif
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// Handles cleanup from transactional memory restart.
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extern "C" void __cxa_tm_cleanup (void *, void *, unsigned int) throw();
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// Invokes given handler, dying appropriately if the user handler was
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// so inconsiderate as to return.
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extern void __terminate(std::terminate_handler) throw ()
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__attribute__((__noreturn__));
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extern void __unexpected(std::unexpected_handler)
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__attribute__((__noreturn__));
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// The current installed user handlers.
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extern std::terminate_handler __terminate_handler;
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extern std::unexpected_handler __unexpected_handler;
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// These are explicitly GNU C++ specific.
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// Acquire the C++ exception header from the C++ object.
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static inline __cxa_exception *
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__get_exception_header_from_obj (void *ptr)
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{
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return reinterpret_cast<__cxa_exception *>(ptr) - 1;
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}
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// Acquire the C++ exception header from the generic exception header.
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static inline __cxa_exception *
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__get_exception_header_from_ue (_Unwind_Exception *exc)
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{
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return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
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}
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// Acquire the C++ refcounted exception header from the C++ object.
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static inline __cxa_refcounted_exception *
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__get_refcounted_exception_header_from_obj (void *ptr)
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{
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return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1;
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}
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// Acquire the C++ refcounted exception header from the generic exception
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// header.
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static inline __cxa_refcounted_exception *
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__get_refcounted_exception_header_from_ue (_Unwind_Exception *exc)
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{
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return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1;
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}
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static inline __cxa_dependent_exception *
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__get_dependent_exception_from_ue (_Unwind_Exception *exc)
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{
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return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1;
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}
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#ifdef __ARM_EABI_UNWINDER__
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static inline bool
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__is_gxx_exception_class(_Unwind_Exception_Class c)
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{
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// TODO: Take advantage of the fact that c will always be word aligned.
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return c[0] == 'G'
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&& c[1] == 'N'
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&& c[2] == 'U'
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&& c[3] == 'C'
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&& c[4] == 'C'
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&& c[5] == '+'
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&& c[6] == '+'
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&& (c[7] == '\0' || c[7] == '\x01');
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}
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// Only checks for primary or dependent, but not that it is a C++ exception at
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// all.
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static inline bool
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__is_dependent_exception(_Unwind_Exception_Class c)
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{
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return c[7] == '\x01';
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}
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static inline void
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__GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c)
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{
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c[0] = 'G';
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c[1] = 'N';
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c[2] = 'U';
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c[3] = 'C';
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c[4] = 'C';
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c[5] = '+';
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c[6] = '+';
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c[7] = '\0';
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}
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static inline void
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__GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c)
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{
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c[0] = 'G';
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c[1] = 'N';
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c[2] = 'U';
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c[3] = 'C';
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c[4] = 'C';
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c[5] = '+';
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c[6] = '+';
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c[7] = '\x01';
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}
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static inline bool
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__is_gxx_forced_unwind_class(_Unwind_Exception_Class c)
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{
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return c[0] == 'G'
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&& c[1] == 'N'
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&& c[2] == 'U'
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&& c[3] == 'C'
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&& c[4] == 'F'
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&& c[5] == 'O'
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&& c[6] == 'R'
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&& c[7] == '\0';
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}
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static inline void
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__GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c)
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{
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c[0] = 'G';
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c[1] = 'N';
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c[2] = 'U';
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c[3] = 'C';
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c[4] = 'F';
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c[5] = 'O';
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c[6] = 'R';
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c[7] = '\0';
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}
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static inline void*
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__gxx_caught_object(_Unwind_Exception* eo)
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{
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return (void*)eo->barrier_cache.bitpattern[0];
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}
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#else // !__ARM_EABI_UNWINDER__
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// This is the primary exception class we report -- "GNUCC++\0".
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const _Unwind_Exception_Class __gxx_primary_exception_class
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= ((((((((_Unwind_Exception_Class) 'G'
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<< 8 | (_Unwind_Exception_Class) 'N')
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<< 8 | (_Unwind_Exception_Class) 'U')
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<< 8 | (_Unwind_Exception_Class) 'C')
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<< 8 | (_Unwind_Exception_Class) 'C')
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<< 8 | (_Unwind_Exception_Class) '+')
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<< 8 | (_Unwind_Exception_Class) '+')
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<< 8 | (_Unwind_Exception_Class) '\0');
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// This is the dependent (from std::rethrow_exception) exception class we report
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// "GNUCC++\x01"
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const _Unwind_Exception_Class __gxx_dependent_exception_class
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= ((((((((_Unwind_Exception_Class) 'G'
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<< 8 | (_Unwind_Exception_Class) 'N')
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<< 8 | (_Unwind_Exception_Class) 'U')
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<< 8 | (_Unwind_Exception_Class) 'C')
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<< 8 | (_Unwind_Exception_Class) 'C')
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<< 8 | (_Unwind_Exception_Class) '+')
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<< 8 | (_Unwind_Exception_Class) '+')
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<< 8 | (_Unwind_Exception_Class) '\x01');
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static inline bool
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__is_gxx_exception_class(_Unwind_Exception_Class c)
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{
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return c == __gxx_primary_exception_class
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|| c == __gxx_dependent_exception_class;
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}
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// Only checks for primary or dependent, but not that it is a C++ exception at
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// all.
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static inline bool
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__is_dependent_exception(_Unwind_Exception_Class c)
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{
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return (c & 1);
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}
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#define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class
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#define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \
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c = __gxx_dependent_exception_class
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// GNU C++ personality routine, Version 0.
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extern "C" _Unwind_Reason_Code __gxx_personality_v0
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(int, _Unwind_Action, _Unwind_Exception_Class,
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struct _Unwind_Exception *, struct _Unwind_Context *);
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// GNU C++ sjlj personality routine, Version 0.
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extern "C" _Unwind_Reason_Code __gxx_personality_sj0
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(int, _Unwind_Action, _Unwind_Exception_Class,
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struct _Unwind_Exception *, struct _Unwind_Context *);
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static inline void*
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__gxx_caught_object(_Unwind_Exception* eo)
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{
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// Bad as it looks, this actually works for dependent exceptions too.
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__cxa_exception* header = __get_exception_header_from_ue (eo);
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return header->adjustedPtr;
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}
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#endif // !__ARM_EABI_UNWINDER__
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static inline void*
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__get_object_from_ue(_Unwind_Exception* eo) throw()
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{
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return __is_dependent_exception (eo->exception_class) ?
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__get_dependent_exception_from_ue (eo)->primaryException :
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eo + 1;
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}
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static inline void *
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__get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw()
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{
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return __get_object_from_ue (&p_or_d->unwindHeader);
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}
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} /* namespace __cxxabiv1 */
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#pragma GCC visibility pop
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#endif // _UNWIND_CXX_H
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