/*
If thrown_object is not null, allocate, initialize and throw a dependent
exception.
*/
void
__cxa_rethrow_primary_exception(void* thrown_object)
{
if ( thrown_object != NULL )
{
// thrown_object guaranteed to be native because
// __cxa_current_primary_exception returns NULL for foreign exceptions
__cxa_exception* exception_header = cxa_exception_from_thrown_object(thrown_object);
__cxa_dependent_exception* dep_exception_header =
static_cast<__cxa_dependent_exception*>(__cxa_allocate_dependent_exception());
dep_exception_header->primaryException = thrown_object;
__cxa_increment_exception_refcount(thrown_object);
dep_exception_header->exceptionType = exception_header->exceptionType;
dep_exception_header->unexpectedHandler = std::get_unexpected();
dep_exception_header->terminateHandler = std::get_terminate();
setDependentExceptionClass(&dep_exception_header->unwindHeader);
__cxa_get_globals()->uncaughtExceptions += 1;
dep_exception_header->unwindHeader.exception_cleanup = dependent_exception_cleanup;
#if __arm__
_Unwind_SjLj_RaiseException(&dep_exception_header->unwindHeader);
#else
_Unwind_RaiseException(&dep_exception_header->unwindHeader);
#endif
// Some sort of unwinding error. Note that terminate is a handler.
__cxa_begin_catch(&dep_exception_header->unwindHeader);
}
// If we return client will call terminate()
}
static LIBCXXABI_NORETURN void failed_throw(__cxa_exception* exception_header) {
// Section 2.5.3 says:
// * For purposes of this ABI, several things are considered exception handlers:
// ** A terminate() call due to a throw.
// and
// * Upon entry, Following initialization of the catch parameter,
// a handler must call:
// * void *__cxa_begin_catch(void *exceptionObject );
(void) __cxa_begin_catch(&exception_header->unwindHeader);
std::__terminate(exception_header->terminateHandler);
}
static
void
call_terminate(bool native_exception, _Unwind_Exception* unwind_exception)
{
__cxa_begin_catch(unwind_exception);
if (native_exception)
{
// Use the stored terminate_handler if possible
__cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1;
std::__terminate(exception_header->terminateHandler);
}
std::terminate();
}
void* __darwin_objc_begin_catch(void* p)
{
void *rv = returnReturn();
void* cpp = __cxa_begin_catch(p);
if (cpp)
{
m_cxx = true;
return cpp;
}
else
{
m_cxx = false;
return rv;
}
}
/* This routine can rethrow native or foreign exceptions.
If the exception is native:
* marks the exception object on top of the caughtExceptions stack
(in an implementation-defined way) as being rethrown.
* If the caughtExceptions stack is empty, it calls terminate()
(see [C++FDIS] [except.throw], 15.1.8).
* It then calls _Unwind_RaiseException which should not return
(terminate if it does).
Note: exception_header may be masquerading as a __cxa_dependent_exception
and that's ok.
*/
LIBCXXABI_NORETURN
void
__cxa_rethrow()
{
__cxa_eh_globals* globals = __cxa_get_globals();
__cxa_exception* exception_header = globals->caughtExceptions;
if (NULL == exception_header)
std::terminate(); // throw; called outside of a exception handler
bool native_exception = isOurExceptionClass(&exception_header->unwindHeader);
if (native_exception)
{
// Mark the exception as being rethrown (reverse the effects of __cxa_begin_catch)
exception_header->handlerCount = -exception_header->handlerCount;
globals->uncaughtExceptions += 1;
// __cxa_end_catch will remove this exception from the caughtExceptions stack if necessary
}
else // this is a foreign exception
{
// The only way to communicate to __cxa_end_catch that we've rethrown
// a foreign exception, so don't delete us, is to pop the stack here
// which must be empty afterwards. Then __cxa_end_catch will do
// nothing
globals->caughtExceptions = 0;
}
#if __arm__
_Unwind_SjLj_RaiseException(&exception_header->unwindHeader);
#else
_Unwind_RaiseException(&exception_header->unwindHeader);
#endif
// If we get here, some kind of unwinding error has occurred.
// There is some weird code generation bug happening with
// Apple clang version 4.0 (tags/Apple/clang-418.0.2) (based on LLVM 3.1svn)
// If we call failed_throw here. Turns up with -O2 or higher, and -Os.
__cxa_begin_catch(&exception_header->unwindHeader);
if (native_exception)
std::__terminate(exception_header->terminateHandler);
// Foreign exception: can't get exception_header->terminateHandler
std::terminate();
}
void
__cxa_call_unexpected(void* arg)
{
_Unwind_Exception* unwind_exception = static_cast<_Unwind_Exception*>(arg);
if (unwind_exception == 0)
call_terminate(false, unwind_exception);
__cxa_begin_catch(unwind_exception);
bool native_old_exception =
(reinterpret_cast<uint64_t>(unwind_exception->exception_class) & get_vendor_and_language) ==
(kOurExceptionClass & get_vendor_and_language);
std::unexpected_handler u_handler;
std::terminate_handler t_handler;
__cxa_exception* old_exception_header = 0;
int64_t ttypeIndex;
const uint8_t* lsda;
if (native_old_exception)
{
old_exception_header = (__cxa_exception*)(unwind_exception+1) - 1;
t_handler = old_exception_header->terminateHandler;
u_handler = old_exception_header->unexpectedHandler;
// If std::__unexpected(u_handler) rethrows the same exception,
// these values get overwritten by the rethrow. So save them now:
#ifndef __ARM_EABI_UNWINDER__
ttypeIndex = old_exception_header->handlerSwitchValue;
lsda = old_exception_header->languageSpecificData;
#endif
}
else
{
t_handler = std::get_terminate();
u_handler = std::get_unexpected();
}
try
{
std::__unexpected(u_handler);
}
catch (...)
{
// If the old exception is foreign, then all we can do is terminate.
// We have no way to recover the needed old exception spec. There's
// no way to pass that information here. And the personality routine
// can't call us directly and do anything but terminate() if we throw
// from here.
if (native_old_exception)
{
// Have:
// old_exception_header->languageSpecificData
// old_exception_header->actionRecord
// Need
// const uint8_t* classInfo
// uint8_t ttypeEncoding
uint8_t lpStartEncoding = *lsda++;
const uint8_t* lpStart = (const uint8_t*)readEncodedPointer(&lsda, lpStartEncoding);
(void)lpStart; // purposefully unused. Just needed to increment lsda.
uint8_t ttypeEncoding = *lsda++;
if (ttypeEncoding == DW_EH_PE_omit)
std::__terminate(t_handler);
uintptr_t classInfoOffset = readULEB128(&lsda);
const uint8_t* classInfo = lsda + classInfoOffset;
// Is this new exception catchable by the exception spec at ttypeIndex?
// The answer is obviously yes if the new and old exceptions are the same exception
// If no
// throw;
__cxa_eh_globals* globals = __cxa_get_globals_fast();
__cxa_exception* new_exception_header = globals->caughtExceptions;
if (new_exception_header == 0)
// This shouldn't be able to happen!
std::__terminate(t_handler);
bool native_new_exception =
(reinterpret_cast<uint64_t>(new_exception_header->unwindHeader.exception_class) & get_vendor_and_language) ==
(kOurExceptionClass & get_vendor_and_language);
void* adjustedPtr;
if (native_new_exception && (new_exception_header != old_exception_header))
{
const __shim_type_info* excpType =
static_cast<const __shim_type_info*>(new_exception_header->exceptionType);
adjustedPtr =
reinterpret_cast<uint64_t>(new_exception_header->unwindHeader.exception_class) == kOurDependentExceptionClass ?
((__cxa_dependent_exception*)new_exception_header)->primaryException :
new_exception_header + 1;
if (!exception_spec_can_catch(ttypeIndex, classInfo, ttypeEncoding,
excpType, adjustedPtr, unwind_exception))
{
// We need to __cxa_end_catch, but for the old exception,
// not the new one. This is a little tricky ...
// Disguise new_exception_header as a rethrown exception, but
// don't actually rethrow it. This means you can temporarily
// end the catch clause enclosing new_exception_header without
// __cxa_end_catch destroying new_exception_header.
new_exception_header->handlerCount = -new_exception_header->handlerCount;
globals->uncaughtExceptions += 1;
// Call __cxa_end_catch for new_exception_header
__cxa_end_catch();
// Call __cxa_end_catch for old_exception_header
__cxa_end_catch();
// Renter this catch clause with new_exception_header
__cxa_begin_catch(&new_exception_header->unwindHeader);
// Rethrow new_exception_header
throw;
}
}
// Will a std::bad_exception be catchable by the exception spec at
// ttypeIndex?
// If no
// throw std::bad_exception();
const __shim_type_info* excpType =
static_cast<const __shim_type_info*>(&typeid(std::bad_exception));
std::bad_exception be;
adjustedPtr = &be;
if (!exception_spec_can_catch(ttypeIndex, classInfo, ttypeEncoding,
excpType, adjustedPtr, unwind_exception))
{
// We need to __cxa_end_catch for both the old exception and the
// new exception. Technically we should do it in that order.
// But it is expedient to do it in the opposite order:
// Call __cxa_end_catch for new_exception_header
__cxa_end_catch();
// Throw std::bad_exception will __cxa_end_catch for
// old_exception_header
throw be;
}
}
}
std::__terminate(t_handler);
}
