TCA emitEndCatchHelper(CodeBlock& cb, UniqueStubs& us) {
auto const udrspo = rvmtl()[unwinderDebuggerReturnSPOff()];
auto const debuggerReturn = vwrap(cb, [&] (Vout& v) {
v << load{udrspo, rvmsp()};
v << storeqi{0, udrspo};
});
svcreq::emit_persistent(cb, folly::none, REQ_POST_DEBUGGER_RET);
auto const resumeCPPUnwind = vwrap(cb, [] (Vout& v) {
static_assert(sizeof(tl_regState) == 1,
"The following store must match the size of tl_regState.");
auto const regstate = emitTLSAddr(v, tls_datum(tl_regState));
v << storebi{static_cast<int32_t>(VMRegState::CLEAN), regstate};
v << load{rvmtl()[unwinderExnOff()], rarg(0)};
v << call{TCA(_Unwind_Resume), arg_regs(1)};
});
us.endCatchHelperPast = cb.frontier();
vwrap(cb, [] (Vout& v) { v << ud2{}; });
alignJmpTarget(cb);
return vwrap(cb, [&] (Vout& v) {
auto const done1 = v.makeBlock();
auto const sf1 = v.makeReg();
v << cmpqim{0, udrspo, sf1};
v << jcci{CC_NE, sf1, done1, debuggerReturn};
v = done1;
// Normal end catch situation: call back to tc_unwind_resume, which returns
// the catch trace (or null) in %rax, and the new vmfp in %rdx.
v << copy{rvmfp(), rarg(0)};
v << call{TCA(tc_unwind_resume)};
v << copy{reg::rdx, rvmfp()};
auto const done2 = v.makeBlock();
auto const sf2 = v.makeReg();
v << testq{reg::rax, reg::rax, sf2};
v << jcci{CC_Z, sf2, done2, resumeCPPUnwind};
v = done2;
// We need to do a syncForLLVMCatch(), but vmfp is already in rdx.
v << jmpr{reg::rax};
});
}
void addDbgGuardImpl(SrcKey sk, SrcRec* sr) {
TCA realCode = sr->getTopTranslation();
if (!realCode) return; // No translations, nothing to do.
auto& cb = mcg->code.main();
auto const dbgGuard = vwrap(cb, [&] (Vout& v) {
if (!sk.resumed()) {
auto const off = sr->nonResumedSPOff();
v << lea{rvmfp()[-cellsToBytes(off.offset)], rvmsp()};
}
auto const tinfo = v.makeReg();
auto const attached = v.makeReg();
auto const sf = v.makeReg();
auto const done = v.makeBlock();
constexpr size_t dbgOff =
offsetof(ThreadInfo, m_reqInjectionData) +
RequestInjectionData::debuggerReadOnlyOffset();
v << ldimmq{reinterpret_cast<uintptr_t>(sk.pc()), rarg(0)};
emitTLSLoad(v, tls_datum(ThreadInfo::s_threadInfo), tinfo);
v << loadb{tinfo[dbgOff], attached};
v << testbi{static_cast<int8_t>(0xffu), attached, sf};
v << jcci{CC_NZ, sf, done, mcg->ustubs().interpHelper};
v = done;
v << fallthru{};
}, CodeKind::Helper);
// Emit a jump to the actual code.
auto const dbgBranchGuardSrc = emitSmashableJmp(cb, realCode);
// Add the guard to the SrcRec.
sr->addDebuggerGuard(dbgGuard, dbgBranchGuardSrc);
}
