TCA fcallHelper(ActRec* ar) {
assert_native_stack_aligned();
assertx(!ar->resumed());
if (LIKELY(!RuntimeOption::EvalFailJitPrologs)) {
auto const tca = mcg->getFuncPrologue(
const_cast<Func*>(ar->m_func),
ar->numArgs(),
ar
);
if (tca) return tca;
}
// Check for stack overflow in the same place func prologues make their
// StackCheck::Early check (see irgen-func-prologue.cpp). This handler also
// cleans and syncs vmRegs for us.
if (checkCalleeStackOverflow(ar)) handleStackOverflow(ar);
try {
VMRegAnchor _(ar);
if (doFCall(ar, vmpc())) {
return mcg->tx().uniqueStubs.resumeHelperRet;
}
// We've been asked to skip the function body (fb_intercept). The vmregs
// have already been fixed; indicate this with a nullptr return.
return nullptr;
} catch (...) {
// The VMRegAnchor above took care of us, but we need to tell the unwinder
// (since ~VMRegAnchor() will have reset tl_regState).
tl_regState = VMRegState::CLEAN;
throw;
}
}
TCA fcallHelper(ActRec* ar, void* sp) {
try {
assert(!ar->resumed());
TCA tca = mcg->getFuncPrologue((Func*)ar->m_func, ar->numArgs(), ar);
if (tca) {
return tca;
}
if (!ar->m_func->isClonedClosure()) {
/*
* If the func is a cloned closure, then the original
* closure has already run the prologue, and the prologues
* array is just being used as entry points for the
* dv funclets. Dont run the prologue again.
*/
VMRegAnchor _(ar);
if (doFCall(ar, vmpc())) {
return mcg->tx().uniqueStubs.resumeHelperRet;
}
// We've been asked to skip the function body
// (fb_intercept). frame, stack and pc have
// already been fixed - flag that with a negative
// return address.
return (TCA)-ar->m_savedRip;
}
setupAfterPrologue(ar, sp);
assert(ar == vmRegsUnsafe().fp);
return mcg->tx().uniqueStubs.resumeHelper;
} catch (...) {
/*
The return address is set to __fcallHelperThunk,
which has no unwind information. Its "logically"
part of the tc, but the c++ unwinder wont know
that. So point our return address at the called
function's return address (which will be in the
tc).
Note that the registers really are clean - we
cleaned them in the try above - so we just
have to tell the unwinder that.
*/
DECLARE_FRAME_POINTER(framePtr);
tl_regState = VMRegState::CLEAN;
framePtr->m_savedRip = ar->m_savedRip;
throw;
}
}
