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// Copyright (C) 2012 The Android Open Source Project
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cxxabi.h>
#include <exception>
#include <pthread.h>
#include "helper_func_internal.h"
namespace {
using namespace __cxxabiv1;
bool isOurCxxException(uint64_t exc) {
// Compatible with GNU
return exc == __gxx_exception_class;
}
void defaultExceptionCleanupFunc(_Unwind_Reason_Code reason, _Unwind_Exception* exc) {
__cxa_free_exception(exc);
}
// Technical note:
// Use a pthread_key_t to hold the key used to store our thread-specific
// __cxa_thread_info objects. The key is created and destroyed through
// a static C++ object.
//
// Due to a bug in the dynamic linker that was only fixed in Froyo, the
// static C++ destructor may be called with a value of NULL for the
// 'this' pointer. As such, any attempt to access any field in the
// object there will result in a crash. To work-around this, store
// the key object as a 'static' variable outside of the C++ object.
static pthread_key_t __cxa_thread_key;
class CxaThreadKey {
public:
// Called at program initialization time, or when the shared library
// is loaded through dlopen().
CxaThreadKey() {
if (pthread_key_create(&__cxa_thread_key, freeObject) != 0) {
fatalError("Can't allocate C++ runtime pthread_key_t");
}
}
// Called at program exit time, or when the shared library is
// unloaded through dlclose(). See note above.
~CxaThreadKey() {
pthread_key_delete(__cxa_thread_key);
}
static __cxa_thread_info* getFast() {
void* obj = pthread_getspecific(__cxa_thread_key);
return reinterpret_cast<__cxa_thread_info*>(obj);
}
static __cxa_thread_info* getSlow() {
void* obj = pthread_getspecific(__cxa_thread_key);
if (obj == NULL) {
obj = malloc(sizeof(__cxa_thread_info));
if (!obj) {
// Shouldn't happen, but better be safe than sorry.
fatalError("Can't allocate thread-specific C++ runtime info block.");
}
memset(obj, 0, sizeof(__cxa_thread_info));
pthread_setspecific(__cxa_thread_key, obj);
}
return reinterpret_cast<__cxa_thread_info*>(obj);
}
private:
// Called when a thread is destroyed.
static void freeObject(void* obj) {
free(obj);
}
};
// The single static instance, this forces the compiler to register
// a constructor and destructor for this object in the final library
// file. They handle the pthread_key_t allocation/deallocation.
static CxaThreadKey instance;
void throwException(__cxa_exception *header) {
__cxa_thread_info *info = CxaThreadKey::getSlow();
header->unexpectedHandler = info->unexpectedHandler;
if (!header->unexpectedHandler) {
header->unexpectedHandler = std::current_unexpected_fn;
}
header->terminateHandler = info->terminateHandler;
if (!header->terminateHandler) {
header->terminateHandler = std::current_terminate_fn;
}
info->globals.uncaughtExceptions += 1;
_Unwind_Reason_Code ret = _Unwind_RaiseException(&header->unwindHeader);
// Should not be here
call_terminate(&header->unwindHeader);
}
} // anonymous namespace
namespace __cxxabiv1 {
extern "C" void __cxa_pure_virtual() {
fatalError("Pure virtual function called!");
}
extern "C" __cxa_eh_globals* __cxa_get_globals() {
__cxa_thread_info* info = CxaThreadKey::getSlow();
return &info->globals;
}
extern "C" __cxa_eh_globals* __cxa_get_globals_fast() {
__cxa_thread_info* info = CxaThreadKey::getFast();
return &info->globals;
}
extern "C" void *__cxa_allocate_exception(size_t thrown_size) {
size_t size = thrown_size + sizeof(__cxa_exception);
__cxa_exception *buffer = static_cast<__cxa_exception*>(malloc(size));
if (!buffer) {
// Since Android uses memory-overcommit, we enter here only when
// the exception object is VERY large. This will propably never happen.
// Therefore, we decide to use no emergency spaces.
fatalError("Not enough memory to allocate exception!");
}
memset(buffer, 0, sizeof(__cxa_exception));
return buffer + 1;
}
extern "C" void __cxa_free_exception(void* thrown_exception) {
__cxa_exception *exc = static_cast<__cxa_exception*>(thrown_exception)-1;
if (exc->exceptionDestructor) {
try {
exc->exceptionDestructor(thrown_exception);
} catch (...) {
fatalError("Exception destructor has thrown!");
}
}
free(exc);
}
extern "C" void __cxa_throw(void* thrown_exc,
std::type_info* tinfo,
void (*dest)(void*)) {
__cxa_exception* header = static_cast<__cxa_exception*>(thrown_exc)-1;
header->exceptionType = tinfo;
header->exceptionDestructor = dest;
header->unwindHeader.exception_class = __gxx_exception_class;
header->unwindHeader.exception_cleanup = defaultExceptionCleanupFunc;
throwException(header);
}
extern "C" void __cxa_rethrow() {
__cxa_eh_globals *globals = __cxa_get_globals();
__cxa_exception* header = globals->caughtExceptions;
_Unwind_Exception* exception = &header->unwindHeader;
if (!header) {
fatalError("Attempting to rethrow an exception that doesn't exist!");
}
if (isOurCxxException(exception->exception_class)) {
header->handlerCount = -header->handlerCount; // Set rethrow flag
} else {
globals->caughtExceptions = 0;
}
throwException(header);
}
extern "C" void* __cxa_begin_catch(void* exc) {
_Unwind_Exception *exception = static_cast<_Unwind_Exception*>(exc);
__cxa_exception* header = reinterpret_cast<__cxa_exception*>(exception+1)-1;
__cxa_eh_globals* globals = __cxa_get_globals();
if (!isOurCxxException(exception->exception_class)) {
if (globals->caughtExceptions) {
fatalError("Can't handle non-C++ exception!");
}
}
// Check rethrow flag
header->handlerCount = (header->handlerCount < 0) ?
(-header->handlerCount+1) : (header->handlerCount+1);
if (header != globals->caughtExceptions) {
header->nextException = globals->caughtExceptions;
globals->caughtExceptions = header;
}
globals->uncaughtExceptions -= 1;
return header->adjustedPtr;
}
extern "C" void __cxa_end_catch() {
__cxa_eh_globals *globals = __cxa_get_globals_fast();
__cxa_exception *header = globals->caughtExceptions;
_Unwind_Exception* exception = &header->unwindHeader;
if (!header) {
return;
}
if (!isOurCxxException(exception->exception_class)) {
globals->caughtExceptions = 0;
_Unwind_DeleteException(exception);
return;
}
int count = header->handlerCount;
if (count < 0) { // Rethrow
if (++count == 0) {
globals->caughtExceptions = header->nextException;
}
} else if (--count == 0) {
globals->caughtExceptions = header->nextException;
__cxa_free_exception(header+1);
return;
} else if (count < 0) {
fatalError("Internal error during exception handling!");
}
header->handlerCount = count;
}
extern "C" void* __cxa_get_exception_ptr(void* exceptionObject) {
__cxa_exception* header =
reinterpret_cast<__cxa_exception*>(
reinterpret_cast<_Unwind_Exception *>(exceptionObject)+1)-1;
return header->adjustedPtr;
}
} // namespace __cxxabiv1