__cxa_call_unexpected takes the in-flight exception's unwind header and
never returns, as in libcxxabi. No std::set_unexpected is exported and
the exception header's unexpected handler is never set, so the handler
is always the default one, which calls std::terminate. It therefore
forwards to libc's __cxa_call_terminate, which begins the catch and runs
the current terminate handler; a null header terminates in libc's
__cxa_begin_catch. libcxxabi's std::terminate would instead run the
terminate handler saved in the exception header at throw time; the two
differ only if std::set_terminate was called in between, which the debt
entry records.
The test shares the forked-child helper of the std::_Pad test, which now
takes the terminate handler to install.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
A failing _Pad primitive threw a host std::runtime_error, which no guest
catch can see. threadcall.cpp calls the checked wrappers of xthread
(_Mtx_lockX, _Cnd_waitX, _Thrd_startX), which pass a non-success code to
_Throw_C_error: _Thrd_nomem and _Thrd_timedout become
resource_unavailable_try_again, _Thrd_busy device_or_resource_busy and
_Thrd_error invalid_argument, raised through _Throw_Cpp_error, which main
now implements. A failing thread start is _Thrd_startX's
resource_unavailable_try_again.
_Release now wakes the launching thread with _Cnd_signal, as
threadcall.cpp does; libc has it since the pad was written.
guest_ampr_threads checks, in a forked child whose guest terminate
handler reports the thrown object, that _Release on the thread still
holding the pad's mutex throws std::system_error with EBUSY. It fails
with the previous host exception and with busy mapped to
invalid_argument.
Implement _ZNSt4_PadC2Ev, _ZNSt4_PadD2Ev, _ZNSt4_Pad7_LaunchEPP7pthread
and _ZNSt4_Pad8_ReleaseEv, which Deathloop (PPSA01670) and Minecraft
Legends (PPSA05510) import from libSceAmpr for the std::thread launch path.
The algorithm and object layout follow Dinkumware V6.00 thr/xthread and
thr/threadcall.cpp of Visual C++ 2013 (ganboing/crt.vc12 f1d47126): a
vtable pointer whose first slot is the pure virtual _Go(), then the
condition and mutex handles and bool _Started (0x8, 0x10, 0x18), with the
console's pointer-to-slot handles of libc Threads.cpp (#3079). The pad
uses libc's _Cnd_*/_Mtx_* exports, starts the guest thread with
pthread_create and an entry that calls _Go() and returns its result as
the exit code, as _Call_func does. The unverified layout, thread
attributes and error reporting are recorded in TechnicalDebt.md.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
Adrià