// -*- C++ -*- Exception handling and frame unwind runtime interface routines.
// Copyright (C) 2001-2015 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3, or (at your option)
// any later version.
//
// GCC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
// This is derived from the C++ ABI for IA-64. Where we diverge
// for cross-architecture compatibility are noted with "@@@".
#ifndef _UNWIND_CXX_H
#define _UNWIND_CXX_H 1
// Level 2: C++ ABI
#include <typeinfo>
#include <exception>
#include <cstddef>
#include "unwind.h"
#include <bits/atomic_word.h>
#include <cxxabi.h>
#ifdef _GLIBCXX_HAVE_SYS_SDT_H
#include <sys/sdt.h>
/* We only want to use stap probes starting with v3. Earlier versions
added too much startup cost. */
#if defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3
#define PROBE2(name, arg1, arg2) STAP_PROBE2 (libstdcxx, name, arg1, arg2)
#endif
#endif
#ifndef PROBE2
#define PROBE2(name, arg1, arg2)
#endif
#pragma GCC visibility push(default)
namespace __cxxabiv1
{
// A primary C++ exception object consists of a header, which is a wrapper
// around an unwind object header with additional C++ specific information,
// followed by the exception object itself.
struct __cxa_exception
{
// Manage the exception object itself.
std::type_info *exceptionType;
void (_GLIBCXX_CDTOR_CALLABI *exceptionDestructor)(void *);
// The C++ standard has entertaining rules wrt calling set_terminate
// and set_unexpected in the middle of the exception cleanup process.
std::unexpected_handler unexpectedHandler;
std::terminate_handler terminateHandler;
// The caught exception stack threads through here.
__cxa_exception *nextException;
// How many nested handlers have caught this exception. A negated
// value is a signal that this object has been rethrown.
int handlerCount;
#ifdef __ARM_EABI_UNWINDER__
// Stack of exceptions in cleanups.
__cxa_exception* nextPropagatingException;
// The number of active cleanup handlers for this exception.
int propagationCount;
#else
// Cache parsed handler data from the personality routine Phase 1
// for Phase 2 and __cxa_call_unexpected.
int handlerSwitchValue;
const unsigned char *actionRecord;
const unsigned char *languageSpecificData;
_Unwind_Ptr catchTemp;
void *adjustedPtr;
#endif
// The generic exception header. Must be last.
_Unwind_Exception unwindHeader;
};
struct __cxa_refcounted_exception
{
// Manage this header.
_Atomic_word referenceCount;
// __cxa_exception must be last, and no padding can be after it.
__cxa_exception exc;
};
// A dependent C++ exception object consists of a wrapper around an unwind
// object header with additional C++ specific information, containing a pointer
// to a primary exception object.
struct __cxa_dependent_exception
{
// The primary exception this thing depends on.
void *primaryException;
// Unused member to get similar layout to __cxa_exception, otherwise the
// alignment requirements of _Unwind_Exception would require padding bytes
// before the unwindHeader member.
void (_GLIBCXX_CDTOR_CALLABI *__padding)(void *);
// The C++ standard has entertaining rules wrt calling set_terminate
// and set_unexpected in the middle of the exception cleanup process.
std::unexpected_handler unexpectedHandler;
std::terminate_handler terminateHandler;
// The caught exception stack threads through here.
__cxa_exception *nextException;
// How many nested handlers have caught this exception. A negated
// value is a signal that this object has been rethrown.
int handlerCount;
#ifdef __ARM_EABI_UNWINDER__
// Stack of exceptions in cleanups.
__cxa_exception* nextPropagatingException;
// The number of active cleanup handlers for this exception.
int propagationCount;
#else
// Cache parsed handler data from the personality routine Phase 1
// for Phase 2 and __cxa_call_unexpected.
int handlerSwitchValue;
const unsigned char *actionRecord;
const unsigned char *languageSpecificData;
_Unwind_Ptr catchTemp;
void *adjustedPtr;
#endif
// The generic exception header. Must be last.
_Unwind_Exception unwindHeader;
};
// Each thread in a C++ program has access to a __cxa_eh_globals object.
struct __cxa_eh_globals
{
__cxa_exception *caughtExceptions;
unsigned int uncaughtExceptions;
#ifdef __ARM_EABI_UNWINDER__
__cxa_exception* propagatingExceptions;
#endif
};
// @@@ These are not directly specified by the IA-64 C++ ABI.
// Handles re-checking the exception specification if unexpectedHandler
// throws, and if bad_exception needs to be thrown. Called from the
// compiler.
extern "C" void __cxa_call_unexpected (void *) __attribute__((__noreturn__));
extern "C" void __cxa_call_terminate (_Unwind_Exception*) throw ()
__attribute__((__noreturn__));
#ifdef __ARM_EABI_UNWINDER__
// Arm EABI specified routines.
typedef enum {
ctm_failed = 0,
ctm_succeeded = 1,
ctm_succeeded_with_ptr_to_base = 2
} __cxa_type_match_result;
extern "C" __cxa_type_match_result __cxa_type_match(_Unwind_Exception*,
const std::type_info*,
bool, void**);
extern "C" bool __cxa_begin_cleanup (_Unwind_Exception*);
extern "C" void __cxa_end_cleanup (void);
#endif
// Handles cleanup from transactional memory restart.
extern "C" void __cxa_tm_cleanup (void *, void *, unsigned int) throw();
// Invokes given handler, dying appropriately if the user handler was
// so inconsiderate as to return.
extern void __terminate(std::terminate_handler) throw ()
__attribute__((__noreturn__));
extern void __unexpected(std::unexpected_handler)
__attribute__((__noreturn__));
// The current installed user handlers.
extern std::terminate_handler __terminate_handler;
extern std::unexpected_handler __unexpected_handler;
// These are explicitly GNU C++ specific.
// Acquire the C++ exception header from the C++ object.
static inline __cxa_exception *
__get_exception_header_from_obj (void *ptr)
{
return reinterpret_cast<__cxa_exception *>(ptr) - 1;
}
// Acquire the C++ exception header from the generic exception header.
static inline __cxa_exception *
__get_exception_header_from_ue (_Unwind_Exception *exc)
{
return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
}
// Acquire the C++ refcounted exception header from the C++ object.
static inline __cxa_refcounted_exception *
__get_refcounted_exception_header_from_obj (void *ptr)
{
return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1;
}
// Acquire the C++ refcounted exception header from the generic exception
// header.
static inline __cxa_refcounted_exception *
__get_refcounted_exception_header_from_ue (_Unwind_Exception *exc)
{
return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1;
}
static inline __cxa_dependent_exception *
__get_dependent_exception_from_ue (_Unwind_Exception *exc)
{
return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1;
}
#ifdef __ARM_EABI_UNWINDER__
static inline bool
__is_gxx_exception_class(_Unwind_Exception_Class c)
{
// TODO: Take advantage of the fact that c will always be word aligned.
return c[0] == 'G'
&& c[1] == 'N'
&& c[2] == 'U'
&& c[3] == 'C'
&& c[4] == 'C'
&& c[5] == '+'
&& c[6] == '+'
&& (c[7] == '\0' || c[7] == '\x01');
}
// Only checks for primary or dependent, but not that it is a C++ exception at
// all.
static inline bool
__is_dependent_exception(_Unwind_Exception_Class c)
{
return c[7] == '\x01';
}
static inline void
__GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c)
{
c[0] = 'G';
c[1] = 'N';
c[2] = 'U';
c[3] = 'C';
c[4] = 'C';
c[5] = '+';
c[6] = '+';
c[7] = '\0';
}
static inline void
__GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c)
{
c[0] = 'G';
c[1] = 'N';
c[2] = 'U';
c[3] = 'C';
c[4] = 'C';
c[5] = '+';
c[6] = '+';
c[7] = '\x01';
}
static inline bool
__is_gxx_forced_unwind_class(_Unwind_Exception_Class c)
{
return c[0] == 'G'
&& c[1] == 'N'
&& c[2] == 'U'
&& c[3] == 'C'
&& c[4] == 'F'
&& c[5] == 'O'
&& c[6] == 'R'
&& c[7] == '\0';
}
static inline void
__GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c)
{
c[0] = 'G';
c[1] = 'N';
c[2] = 'U';
c[3] = 'C';
c[4] = 'F';
c[5] = 'O';
c[6] = 'R';
c[7] = '\0';
}
static inline void*
__gxx_caught_object(_Unwind_Exception* eo)
{
return (void*)eo->barrier_cache.bitpattern[0];
}
#else // !__ARM_EABI_UNWINDER__
// This is the primary exception class we report -- "GNUCC++\0".
const _Unwind_Exception_Class __gxx_primary_exception_class
= ((((((((_Unwind_Exception_Class) 'G'
<< 8 | (_Unwind_Exception_Class) 'N')
<< 8 | (_Unwind_Exception_Class) 'U')
<< 8 | (_Unwind_Exception_Class) 'C')
<< 8 | (_Unwind_Exception_Class) 'C')
<< 8 | (_Unwind_Exception_Class) '+')
<< 8 | (_Unwind_Exception_Class) '+')
<< 8 | (_Unwind_Exception_Class) '\0');
// This is the dependent (from std::rethrow_exception) exception class we report
// "GNUCC++\x01"
const _Unwind_Exception_Class __gxx_dependent_exception_class
= ((((((((_Unwind_Exception_Class) 'G'
<< 8 | (_Unwind_Exception_Class) 'N')
<< 8 | (_Unwind_Exception_Class) 'U')
<< 8 | (_Unwind_Exception_Class) 'C')
<< 8 | (_Unwind_Exception_Class) 'C')
<< 8 | (_Unwind_Exception_Class) '+')
<< 8 | (_Unwind_Exception_Class) '+')
<< 8 | (_Unwind_Exception_Class) '\x01');
static inline bool
__is_gxx_exception_class(_Unwind_Exception_Class c)
{
return c == __gxx_primary_exception_class
|| c == __gxx_dependent_exception_class;
}
// Only checks for primary or dependent, but not that it is a C++ exception at
// all.
static inline bool
__is_dependent_exception(_Unwind_Exception_Class c)
{
return (c & 1);
}
#define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class
#define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \
c = __gxx_dependent_exception_class
// GNU C++ personality routine, Version 0.
extern "C" _Unwind_Reason_Code __gxx_personality_v0
(int, _Unwind_Action, _Unwind_Exception_Class,
struct _Unwind_Exception *, struct _Unwind_Context *);
// GNU C++ sjlj personality routine, Version 0.
extern "C" _Unwind_Reason_Code __gxx_personality_sj0
(int, _Unwind_Action, _Unwind_Exception_Class,
struct _Unwind_Exception *, struct _Unwind_Context *);
static inline void*
__gxx_caught_object(_Unwind_Exception* eo)
{
// Bad as it looks, this actually works for dependent exceptions too.
__cxa_exception* header = __get_exception_header_from_ue (eo);
return header->adjustedPtr;
}
#endif // !__ARM_EABI_UNWINDER__
static inline void*
__get_object_from_ue(_Unwind_Exception* eo) throw()
{
return __is_dependent_exception (eo->exception_class) ?
__get_dependent_exception_from_ue (eo)->primaryException :
eo + 1;
}
static inline void *
__get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw()
{
return __get_object_from_ue (&p_or_d->unwindHeader);
}
} /* namespace __cxxabiv1 */
#pragma GCC visibility pop
#endif // _UNWIND_CXX_H