/* Return bytecode position for function/frame or NO_BCPOS. */
static BCPos debug_framepc(lua_State *L, GCfunc *fn, cTValue *nextframe)
{
const BCIns *ins;
GCproto *pt;
BCPos pos;
lua_assert(fn->c.gct == ~LJ_TFUNC || fn->c.gct == ~LJ_TTHREAD);
if (!isluafunc(fn)) { /* Cannot derive a PC for non-Lua functions. */
return NO_BCPOS;
} else if (nextframe == NULL) { /* Lua function on top. */
void *cf = cframe_raw(L->cframe);
if (cf == NULL || (char *)cframe_pc(cf) == (char *)cframe_L(cf))
return NO_BCPOS;
ins = cframe_pc(cf); /* Only happens during error/hook handling. */
} else {
if (frame_islua(nextframe)) {
ins = frame_pc(nextframe);
} else if (frame_iscont(nextframe)) {
ins = frame_contpc(nextframe);
} else {
/* Lua function below errfunc/gc/hook: find cframe to get the PC. */
void *cf = cframe_raw(L->cframe);
TValue *f = L->base-1;
for (;;) {
if (cf == NULL)
return NO_BCPOS;
while (cframe_nres(cf) < 0) {
if (f >= restorestack(L, -cframe_nres(cf)))
break;
cf = cframe_raw(cframe_prev(cf));
if (cf == NULL)
return NO_BCPOS;
}
if (f < nextframe)
break;
if (frame_islua(f)) {
f = frame_prevl(f);
} else {
if (frame_isc(f) || (LJ_HASFFI && frame_iscont(f) &&
(f-1)->u32.lo == LJ_CONT_FFI_CALLBACK))
cf = cframe_raw(cframe_prev(cf));
f = frame_prevd(f);
}
}
ins = cframe_pc(cf);
}
}
pt = funcproto(fn);
pos = proto_bcpos(pt, ins) - 1;
#if LJ_HASJIT
if (pos > pt->sizebc) { /* Undo the effects of lj_trace_exit for JLOOP. */
GCtrace *T = (GCtrace *)((char *)(ins-1) - offsetof(GCtrace, startins));
lua_assert(bc_isret(bc_op(ins[-1])));
pos = proto_bcpos(pt, mref(T->startpc, const BCIns));
}
/* Find error function for runtime errors. Requires an extra stack traversal. */
static ptrdiff_t finderrfunc(lua_State *L)
{
cTValue *frame = L->base-1, *bot = tvref(L->stack);
void *cf = L->cframe;
while (frame > bot && cf) {
while (cframe_nres(cframe_raw(cf)) < 0) { /* cframe without frame? */
if (frame >= restorestack(L, -cframe_nres(cf)))
break;
if (cframe_errfunc(cf) >= 0) /* Error handler not inherited (-1)? */
return cframe_errfunc(cf);
cf = cframe_prev(cf); /* Else unwind cframe and continue searching. */
if (cf == NULL)
return 0;
}
switch (frame_typep(frame)) {
case FRAME_LUA:
case FRAME_LUAP:
frame = frame_prevl(frame);
break;
case FRAME_C:
cf = cframe_prev(cf);
/* fallthrough */
case FRAME_VARG:
frame = frame_prevd(frame);
break;
case FRAME_CONT:
#if LJ_HASFFI
if ((frame-1)->u32.lo == LJ_CONT_FFI_CALLBACK)
cf = cframe_prev(cf);
#endif
frame = frame_prevd(frame);
break;
case FRAME_CP:
if (cframe_canyield(cf)) return 0;
if (cframe_errfunc(cf) >= 0)
return cframe_errfunc(cf);
frame = frame_prevd(frame);
break;
case FRAME_PCALL:
case FRAME_PCALLH:
if (frame_ftsz(frame) >= (ptrdiff_t)(2*sizeof(TValue))) /* xpcall? */
return savestack(L, frame-1); /* Point to xpcall's errorfunc. */
return 0;
default:
lua_assert(0);
return 0;
}
}
return 0;
}
/* Find error function for runtime errors. Requires an extra stack traversal. */
static ptrdiff_t finderrfunc(lua_State *L)
{
cTValue *frame = L->base-1, *bot = tvref(L->stack)+LJ_FR2;
void *cf = L->cframe;
while (frame > bot && cf) {
while (cframe_nres(cframe_raw(cf)) < 0) { /* cframe without frame? */
if (frame >= restorestack(L, -cframe_nres(cf)))
break;
if (cframe_errfunc(cf) >= 0) /* Error handler not inherited (-1)? */
return cframe_errfunc(cf);
cf = cframe_prev(cf); /* Else unwind cframe and continue searching. */
if (cf == NULL)
return 0;
}
switch (frame_typep(frame)) {
case FRAME_LUA:
case FRAME_LUAP:
frame = frame_prevl(frame);
break;
case FRAME_C:
cf = cframe_prev(cf);
/* fallthrough */
case FRAME_VARG:
frame = frame_prevd(frame);
break;
case FRAME_CONT:
if (frame_iscont_fficb(frame))
cf = cframe_prev(cf);
frame = frame_prevd(frame);
break;
case FRAME_CP:
if (cframe_canyield(cf)) return 0;
if (cframe_errfunc(cf) >= 0)
return cframe_errfunc(cf);
frame = frame_prevd(frame);
break;
case FRAME_PCALL:
case FRAME_PCALLH:
if (frame_func(frame_prevd(frame))->c.ffid == FF_xpcall)
return savestack(L, frame_prevd(frame)+1); /* xpcall's errorfunc. */
return 0;
default:
lua_assert(0);
return 0;
}
}
return 0;
}
/* Unwind until stop frame. Optionally cleanup frames. */
static void *err_unwind(lua_State *L, void *stopcf, int errcode)
{
TValue *frame = L->base-1;
void *cf = L->cframe;
while (cf) {
int32_t nres = cframe_nres(cframe_raw(cf));
if (nres < 0) { /* C frame without Lua frame? */
TValue *top = restorestack(L, -nres);
if (frame < top) { /* Frame reached? */
if (errcode) {
L->cframe = cframe_prev(cf);
L->base = frame+1;
unwindstack(L, top);
}
return cf;
}
}
if (frame <= tvref(L->stack))
break;
switch (frame_typep(frame)) {
case FRAME_LUA: /* Lua frame. */
case FRAME_LUAP:
frame = frame_prevl(frame);
break;
case FRAME_C: /* C frame. */
#if LJ_UNWIND_EXT
if (errcode) {
L->cframe = cframe_prev(cf);
L->base = frame_prevd(frame) + 1;
unwindstack(L, frame);
} else if (cf != stopcf) {
cf = cframe_prev(cf);
frame = frame_prevd(frame);
break;
}
return NULL; /* Continue unwinding. */
#else
UNUSED(stopcf);
cf = cframe_prev(cf);
frame = frame_prevd(frame);
break;
#endif
case FRAME_CP: /* Protected C frame. */
if (cframe_canyield(cf)) { /* Resume? */
if (errcode) {
L->cframe = NULL;
L->status = (uint8_t)errcode;
}
return cf;
}
if (errcode) {
L->cframe = cframe_prev(cf);
L->base = frame_prevd(frame) + 1;
unwindstack(L, frame);
}
return cf;
case FRAME_CONT: /* Continuation frame. */
case FRAME_VARG: /* Vararg frame. */
frame = frame_prevd(frame);
break;
case FRAME_PCALL: /* FF pcall() frame. */
case FRAME_PCALLH: /* FF pcall() frame inside hook. */
if (errcode) {
if (errcode == LUA_YIELD) {
frame = frame_prevd(frame);
break;
}
if (frame_typep(frame) == FRAME_PCALL)
hook_leave(G(L));
L->cframe = cf;
L->base = frame_prevd(frame) + 1;
unwindstack(L, L->base);
}
return (void *)((intptr_t)cf | CFRAME_UNWIND_FF);
}
}
/* No C frame. */
if (errcode) {
L->cframe = NULL;
L->base = tvref(L->stack)+1;
unwindstack(L, L->base);
if (G(L)->panic)
G(L)->panic(L);
exit(EXIT_FAILURE);
}
return L; /* Anything non-NULL will do. */
}