/* 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;
}
/* Typecheck error for __call. */
LJ_NOINLINE void lj_err_optype_call(lua_State *L, TValue *o)
{
/* Gross hack if lua_[p]call or pcall/xpcall fail for a non-callable object:
** L->base still points to the caller. So add a dummy frame with L instead
** of a function. See lua_getstack().
*/
const BCIns *pc = cframe_Lpc(L);
if (((ptrdiff_t)pc & FRAME_TYPE) != FRAME_LUA) {
const char *tname = typename(o);
setframe_pc(o, pc);
setframe_gc(o, obj2gco(L));
L->top = L->base = o+1;
err_msgv(L, LJ_ERR_BADCALL, tname);
}
lj_err_optype(L, o, LJ_ERR_OPCALL);
}
/* 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;
}
