Index: include/unwind.h =================================================================== --- include/unwind.h +++ include/unwind.h @@ -63,6 +63,8 @@ static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME = 0; static const _Unwind_State _US_UNWIND_FRAME_STARTING = 1; static const _Unwind_State _US_UNWIND_FRAME_RESUME = 2; +/* Undocumented flag for force unwinding. */ +static const _Unwind_State _US_FORCE_UNWIND = 8; typedef uint32_t _Unwind_EHT_Header; Index: src/cxa_personality.cpp =================================================================== --- src/cxa_personality.cpp +++ src/cxa_personality.cpp @@ -1101,9 +1101,16 @@ _Unwind_SetGR(context, REG_UCB, reinterpret_cast(unwind_exception)); #endif + // Check the undocumented force unwinding behavior + bool is_force_unwinding = state & _US_FORCE_UNWIND; + state &= ~_US_FORCE_UNWIND; + scan_results results; switch (state) { case _US_VIRTUAL_UNWIND_FRAME: + if (is_force_unwinding) + return continue_unwind(unwind_exception, context); + // Phase 1 search: All we're looking for in phase 1 is a handler that halts unwinding scan_eh_tab(results, _UA_SEARCH_PHASE, native_exception, unwind_exception, context); if (results.reason == _URC_HANDLER_FOUND) @@ -1119,6 +1126,11 @@ return results.reason; case _US_UNWIND_FRAME_STARTING: + // TODO: Support force unwinding in the phase 2 search. + // NOTE: In order to call the cleanup functions, _Unwind_ForcedUnwind() + // will call this personality function with (_US_FORCE_UNWIND | + // _US_UNWIND_FRAME_STARTING). + // Phase 2 search if (unwind_exception->barrier_cache.sp == _Unwind_GetGR(context, REG_SP)) {