/* Add frame links at the end of the snapshot. */
static BCReg snapshot_framelinks(jit_State *J, SnapEntry *map)
{
cTValue *frame = J->L->base - 1;
cTValue *lim = J->L->base - J->baseslot;
GCfunc *fn = frame_func(frame);
cTValue *ftop = isluafunc(fn) ? (frame+funcproto(fn)->framesize) : J->L->top;
MSize f = 0;
lua_assert(!LJ_FR2); /* TODO_FR2: store 64 bit PCs. */
map[f++] = SNAP_MKPC(J->pc); /* The current PC is always the first entry. */
while (frame > lim) { /* Backwards traversal of all frames above base. */
if (frame_islua(frame)) {
map[f++] = SNAP_MKPC(frame_pc(frame));
frame = frame_prevl(frame);
} else if (frame_iscont(frame)) {
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
map[f++] = SNAP_MKPC(frame_contpc(frame));
frame = frame_prevd(frame);
} else {
lua_assert(!frame_isc(frame));
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
frame = frame_prevd(frame);
continue;
}
if (frame + funcproto(frame_func(frame))->framesize > ftop)
ftop = frame + funcproto(frame_func(frame))->framesize;
}
lua_assert(f == (MSize)(1 + J->framedepth));
return (BCReg)(ftop - lim);
}
/* Tailcall from C function. */
int lj_meta_tailcall(lua_State *L, cTValue *tv)
{
TValue *base = L->base;
TValue *top = L->top;
const BCIns *pc = frame_pc(base-1); /* Preserve old PC from frame. */
copyTV(L, base-1-LJ_FR2, tv); /* Replace frame with new object. */
if (LJ_FR2)
(top++)->u64 = LJ_CONT_TAILCALL;
else
top->u32.lo = LJ_CONT_TAILCALL;
setframe_pc(top++, pc);
if (LJ_FR2) top++;
setframe_gc(top, obj2gco(L), LJ_TTHREAD); /* Dummy frame object. */
setframe_ftsz(top, ((char *)(top+1) - (char *)base) + FRAME_CONT);
L->base = L->top = top+1;
/*
** before: [old_mo|PC] [... ...]
** ^base ^top
** after: [new_mo|itype] [... ...] [NULL|PC] [dummy|delta]
** ^base/top
** tailcall: [new_mo|PC] [... ...]
** ^base ^top
*/
return 0;
}
/* Return number of results wanted by caller. */
static ptrdiff_t results_wanted(jit_State *J)
{
TValue *frame = J->L->base-1;
if (frame_islua(frame))
return (ptrdiff_t)bc_b(frame_pc(frame)[-1]) - 1;
else
return -1;
}
/* 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));
}
/* Tailcall from C function. */
int lj_meta_tailcall(lua_State *L, cTValue *tv)
{
TValue *base = L->base;
TValue *top = L->top;
const BCIns *pc = frame_pc(base-1); /* Preserve old PC from frame. */
copyTV(L, base-1, tv); /* Replace frame with new object. */
top->u64 = 0;
setframe_pc(top, pc);
setframe_gc(top+1, obj2gco(L)); /* Dummy frame object. */
setframe_ftsz(top+1, (int)((char *)(top+2) - (char *)base) + FRAME_CONT);
L->base = L->top = top+2;
/*
** before: [old_mo|PC] [... ...]
** ^base ^top
** after: [new_mo|itype] [... ...] [NULL|PC] [dummy|delta]
** ^base/top
** tailcall: [new_mo|PC] [... ...]
** ^base ^top
*/
return 0;
}
/* Add frame links at the end of the snapshot. */
static void snapshot_framelinks(jit_State *J, SnapEntry *map)
{
cTValue *frame = J->L->base - 1;
cTValue *lim = J->L->base - J->baseslot;
MSize f = 0;
map[f++] = SNAP_MKPC(J->pc); /* The current PC is always the first entry. */
while (frame > lim) { /* Backwards traversal of all frames above base. */
if (frame_islua(frame)) {
map[f++] = SNAP_MKPC(frame_pc(frame));
frame = frame_prevl(frame);
} else if (frame_iscont(frame)) {
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
map[f++] = SNAP_MKPC(frame_contpc(frame));
frame = frame_prevd(frame);
} else {
lua_assert(!frame_isc(frame));
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
frame = frame_prevd(frame);
}
}
lua_assert(f == (MSize)(1 + J->framedepth));
}
/* Add frame links at the end of the snapshot. */
static MSize snapshot_framelinks(jit_State *J, IRRef2 *map)
{
cTValue *frame = J->L->base - 1;
cTValue *lim = J->L->base - J->baseslot;
MSize f = 0;
map[f++] = u32ptr(J->pc);
while (frame > lim) {
if (frame_islua(frame)) {
map[f++] = u32ptr(frame_pc(frame));
frame = frame_prevl(frame);
} else if (frame_ispcall(frame)) {
map[f++] = (uint32_t)frame_ftsz(frame);
frame = frame_prevd(frame);
} else if (frame_iscont(frame)) {
map[f++] = (uint32_t)frame_ftsz(frame);
map[f++] = u32ptr(frame_contpc(frame));
frame = frame_prevd(frame);
} else {
lua_assert(0);
}
}
return f;
}