c_ResumableWaitHandle* c_ResumableWaitHandle::getRunning(ActRec* fp) {
for (; fp; fp = g_context->getPrevVMState(fp)) {
if (fp->resumed() && fp->func()->isAsync()) {
if (fp->func()->isGenerator()) {
// async generator
auto generator = frame_async_generator(fp);
if (!generator->isEagerlyExecuted()) {
return generator->getWaitHandle();
}
} else {
// async function
return frame_afwh(fp);
}
}
}
return nullptr;
}
void EventHook::onFunctionSuspendE(ActRec* suspending,
const ActRec* resumableAR) {
// When we're suspending an eagerly executing resumable, we've already
// teleported the ActRec from suspending over to resumableAR, so we need to
// make sure the unwinder knows not to touch the locals, $this, or
// VarEnv/ExtraArgs.
suspending->setThisOrClassAllowNull(nullptr);
suspending->setLocalsDecRefd();
suspending->setVarEnv(nullptr);
try {
auto const flags = check_request_surprise();
onFunctionExit(resumableAR, nullptr, false, nullptr, flags);
if ((flags & AsyncEventHookFlag) &&
resumableAR->func()->isAsyncFunction()) {
assert(resumableAR->resumed());
auto const afwh = frame_afwh(resumableAR);
auto const session = AsioSession::Get();
if (session->hasOnResumableCreate()) {
session->onResumableCreate(afwh, afwh->getChild());
}
}
} catch (...) {
auto const resumableObj = [&]() -> ObjectData* {
if (resumableAR->func()->isAsyncFunction()) {
return frame_afwh(resumableAR);
}
assert(resumableAR->func()->isGenerator());
return !resumableAR->func()->isAsync()
? frame_generator(resumableAR)->toObject()
: frame_async_generator(resumableAR)->toObject();
}();
decRefObj(resumableObj);
throw;
}
}
/**
* Discard the current frame, assuming that a PHP exception given in
* phpException argument, or C++ exception (phpException == nullptr)
* is being thrown. Returns an exception to propagate, or nulltpr
* if the VM execution should be resumed.
*/
ObjectData* tearDownFrame(ActRec*& fp, Stack& stack, PC& pc,
ObjectData* phpException) {
auto const func = fp->func();
auto const curOp = peek_op(pc);
auto const prevFp = fp->sfp();
auto const soff = fp->m_soff;
ITRACE(1, "tearDownFrame: {} ({})\n",
func->fullName()->data(),
func->unit()->filepath()->data());
ITRACE(1, " fp {} prevFp {}\n",
implicit_cast<void*>(fp),
implicit_cast<void*>(prevFp));
// When throwing from a constructor, we normally want to avoid running the
// destructor on an object that hasn't been fully constructed yet. But if
// we're unwinding through the constructor's RetC, the constructor has
// logically finished and we're unwinding for some internal reason (timeout
// or user profiler, most likely). More importantly, fp->m_this may have
// already been destructed and/or overwritten due to sharing space with
// fp->m_r.
if (curOp != OpRetC &&
fp->hasThis() &&
fp->getThis()->getVMClass()->getCtor() == func &&
fp->getThis()->getVMClass()->getDtor()) {
/*
* Looks like an FPushCtor call, but it could still have been called
* directly. Check the fpi region to be sure.
*/
Offset prevPc;
auto outer = g_context->getPrevVMState(fp, &prevPc);
if (outer) {
auto fe = outer->func()->findPrecedingFPI(prevPc);
if (fe && isFPushCtor(outer->func()->unit()->getOp(fe->m_fpushOff))) {
fp->getThis()->setNoDestruct();
}
}
}
auto const decRefLocals = [&] {
/*
* It is possible that locals have already been decref'd.
*
* Here's why:
*
* - If a destructor for any of these things throws a php
* exception, it's swallowed at the dtor boundary and we keep
* running php.
*
* - If the destructor for any of these things throws a fatal,
* it's swallowed, and we set surprise flags to throw a fatal
* from now on.
*
* - If the second case happened and we have to run another
* destructor, its enter hook will throw, but it will be
* swallowed again.
*
* - Finally, the exit hook for the returning function can
* throw, but this happens last so everything is destructed.
*
* - When that happens, exit hook sets localsDecRefd flag.
*/
if (!fp->localsDecRefd()) {
try {
// Note that we must convert locals and the $this to
// uninit/zero during unwind. This is because a backtrace
// from another destructing object during this unwind may try
// to read them.
frame_free_locals_unwind(fp, func->numLocals(), phpException);
} catch (...) {}
}
};
if (LIKELY(!fp->resumed())) {
decRefLocals();
if (UNLIKELY(func->isAsyncFunction()) &&
phpException &&
!fp->isFCallAwait()) {
// If in an eagerly executed async function, wrap the user exception
// into a failed StaticWaitHandle and return it to the caller.
auto const waitHandle = c_StaticWaitHandle::CreateFailed(phpException);
phpException = nullptr;
stack.ndiscard(func->numSlotsInFrame());
stack.ret();
assert(stack.topTV() == &fp->m_r);
cellCopy(make_tv<KindOfObject>(waitHandle), fp->m_r);
} else {
// Free ActRec.
stack.ndiscard(func->numSlotsInFrame());
stack.discardAR();
}
} else if (func->isAsyncFunction()) {
auto const waitHandle = frame_afwh(fp);
if (phpException) {
// Handle exception thrown by async function.
decRefLocals();
waitHandle->fail(phpException);
phpException = nullptr;
} else if (waitHandle->isRunning()) {
// Let the C++ exception propagate. If the current frame represents async
// function that is running, mark it as abruptly interrupted. Some opcodes
// like Await may change state of the async function just before exit hook
// decides to throw C++ exception.
decRefLocals();
waitHandle->failCpp();
}
} else if (func->isAsyncGenerator()) {
auto const gen = frame_async_generator(fp);
if (phpException) {
// Handle exception thrown by async generator.
decRefLocals();
auto eagerResult = gen->fail(phpException);
phpException = nullptr;
if (eagerResult) {
stack.pushObjectNoRc(eagerResult);
}
} else if (gen->isEagerlyExecuted() || gen->getWaitHandle()->isRunning()) {
// Fail the async generator and let the C++ exception propagate.
decRefLocals();
gen->failCpp();
}
} else if (func->isNonAsyncGenerator()) {
// Mark the generator as finished.
decRefLocals();
frame_generator(fp)->fail();
} else {
not_reached();
}
/*
* At the final ActRec in this nesting level.
*/
if (UNLIKELY(!prevFp)) {
pc = nullptr;
fp = nullptr;
return phpException;
}
assert(stack.isValidAddress(reinterpret_cast<uintptr_t>(prevFp)) ||
prevFp->resumed());
auto const prevOff = soff + prevFp->func()->base();
pc = prevFp->func()->unit()->at(prevOff);
fp = prevFp;
return phpException;
}
