/* Copy-substitute snapshot. */
static void loop_subst_snap(jit_State *J, SnapShot *osnap,
SnapEntry *loopmap, IRRef1 *subst)
{
SnapEntry *nmap, *omap = &J->cur.snapmap[osnap->mapofs];
SnapEntry *nextmap = &J->cur.snapmap[snap_nextofs(&J->cur, osnap)];
MSize nmapofs;
MSize on, ln, nn, onent = osnap->nent;
BCReg nslots = osnap->nslots;
SnapShot *snap = &J->cur.snap[J->cur.nsnap];
if (irt_isguard(J->guardemit)) { /* Guard inbetween? */
nmapofs = J->cur.nsnapmap;
J->cur.nsnap++; /* Add new snapshot. */
} else { /* Otherwise overwrite previous snapshot. */
snap--;
nmapofs = snap->mapofs;
}
J->guardemit.irt = 0;
/* Setup new snapshot. */
snap->mapofs = (uint16_t)nmapofs;
snap->ref = (IRRef1)J->cur.nins;
snap->nslots = nslots;
snap->topslot = osnap->topslot;
snap->count = 0;
nmap = &J->cur.snapmap[nmapofs];
/* Substitute snapshot slots. */
on = ln = nn = 0;
while (on < onent) {
SnapEntry osn = omap[on], lsn = loopmap[ln];
if (snap_slot(lsn) < snap_slot(osn)) { /* Copy slot from loop map. */
nmap[nn++] = lsn;
ln++;
} else { /* Copy substituted slot from snapshot map. */
if (snap_slot(lsn) == snap_slot(osn)) ln++; /* Shadowed loop slot. */
if (!irref_isk(snap_ref(osn)))
osn = snap_setref(osn, subst[snap_ref(osn)]);
nmap[nn++] = osn;
on++;
}
}
while (snap_slot(loopmap[ln]) < nslots) /* Copy remaining loop slots. */
nmap[nn++] = loopmap[ln++];
snap->nent = (uint8_t)nn;
omap += onent;
nmap += nn;
while (omap < nextmap) /* Copy PC + frame links. */
*nmap++ = *omap++;
J->cur.nsnapmap = (uint16_t)(nmap - J->cur.snapmap);
}
/* Restore interpreter state from exit state with the help of a snapshot. */
const BCIns *lj_snap_restore(jit_State *J, void *exptr)
{
ExitState *ex = (ExitState *)exptr;
SnapNo snapno = J->exitno; /* For now, snapno == exitno. */
GCtrace *T = traceref(J, J->parent);
SnapShot *snap = &T->snap[snapno];
MSize n, nent = snap->nent;
SnapEntry *map = &T->snapmap[snap->mapofs];
SnapEntry *flinks = &T->snapmap[snap_nextofs(T, snap)-1];
ptrdiff_t ftsz0;
TValue *frame;
BloomFilter rfilt = snap_renamefilter(T, snapno);
const BCIns *pc = snap_pc(map[nent]);
lua_State *L = J->L;
/* Set interpreter PC to the next PC to get correct error messages. */
setcframe_pc(cframe_raw(L->cframe), pc+1);
/* Make sure the stack is big enough for the slots from the snapshot. */
if (LJ_UNLIKELY(L->base + snap->topslot >= tvref(L->maxstack))) {
L->top = curr_topL(L);
lj_state_growstack(L, snap->topslot - curr_proto(L)->framesize);
}
/* Fill stack slots with data from the registers and spill slots. */
frame = L->base-1;
ftsz0 = frame_ftsz(frame); /* Preserve link to previous frame in slot #0. */
for (n = 0; n < nent; n++) {
SnapEntry sn = map[n];
if (!(sn & SNAP_NORESTORE)) {
TValue *o = &frame[snap_slot(sn)];
IRRef ref = snap_ref(sn);
IRIns *ir = &T->ir[ref];
if (ir->r == RID_SUNK) {
MSize j;
for (j = 0; j < n; j++)
if (snap_ref(map[j]) == ref) { /* De-duplicate sunk allocations. */
copyTV(L, o, &frame[snap_slot(map[j])]);
goto dupslot;
}
snap_unsink(J, T, ex, snapno, rfilt, ir, o);
dupslot:
continue;
}
snap_restoreval(J, T, ex, snapno, rfilt, ref, o);
if (LJ_SOFTFP && (sn & SNAP_SOFTFPNUM) && tvisint(o)) {
TValue tmp;
snap_restoreval(J, T, ex, snapno, rfilt, ref+1, &tmp);
o->u32.hi = tmp.u32.lo;
} else if ((sn & (SNAP_CONT|SNAP_FRAME))) {
lua_assert(!LJ_FR2); /* TODO_FR2: store 64 bit PCs. */
/* Overwrite tag with frame link. */
setframe_ftsz(o, snap_slot(sn) != 0 ? (int32_t)*flinks-- : ftsz0);
L->base = o+1;
}
}
}
lua_assert(map + nent == flinks);
/* Compute current stack top. */
switch (bc_op(*pc)) {
default:
if (bc_op(*pc) < BC_FUNCF) {
L->top = curr_topL(L);
break;
}
/* fallthrough */
case BC_CALLM: case BC_CALLMT: case BC_RETM: case BC_TSETM:
L->top = frame + snap->nslots;
break;
}
return pc;
}
/* Restore interpreter state from exit state with the help of a snapshot. */
const BCIns *lj_snap_restore(jit_State *J, void *exptr)
{
ExitState *ex = (ExitState *)exptr;
SnapNo snapno = J->exitno; /* For now, snapno == exitno. */
GCtrace *T = traceref(J, J->parent);
SnapShot *snap = &T->snap[snapno];
MSize n, nent = snap->nent;
SnapEntry *map = &T->snapmap[snap->mapofs];
SnapEntry *flinks = &T->snapmap[snap_nextofs(T, snap)-1];
int32_t ftsz0;
TValue *frame;
BloomFilter rfilt = snap_renamefilter(T, snapno);
const BCIns *pc = snap_pc(map[nent]);
lua_State *L = J->L;
/* Set interpreter PC to the next PC to get correct error messages. */
setcframe_pc(cframe_raw(L->cframe), pc+1);
/* Make sure the stack is big enough for the slots from the snapshot. */
if (LJ_UNLIKELY(L->base + snap->topslot >= tvref(L->maxstack))) {
L->top = curr_topL(L);
lj_state_growstack(L, snap->topslot - curr_proto(L)->framesize);
}
/* Fill stack slots with data from the registers and spill slots. */
frame = L->base-1;
ftsz0 = frame_ftsz(frame); /* Preserve link to previous frame in slot #0. */
for (n = 0; n < nent; n++) {
SnapEntry sn = map[n];
IRRef ref = snap_ref(sn);
BCReg s = snap_slot(sn);
TValue *o = &frame[s]; /* Stack slots are relative to start frame. */
IRIns *ir = &T->ir[ref];
if (irref_isk(ref)) { /* Restore constant slot. */
lj_ir_kvalue(L, o, ir);
} else if (!(sn & SNAP_NORESTORE)) {
IRType1 t = ir->t;
RegSP rs = ir->prev;
if (LJ_UNLIKELY(bloomtest(rfilt, ref)))
rs = snap_renameref(T, snapno, ref, rs);
if (ra_hasspill(regsp_spill(rs))) { /* Restore from spill slot. */
int32_t *sps = &ex->spill[regsp_spill(rs)];
if (LJ_SOFTFP && (sn & SNAP_SOFTFPNUM)) {
o->u32.lo = (uint32_t)*sps;
} else if (irt_isinteger(t)) {
setintV(o, *sps);
#if !LJ_SOFTFP
} else if (irt_isnum(t)) {
o->u64 = *(uint64_t *)sps;
#endif
#if LJ_64
} else if (irt_islightud(t)) {
/* 64 bit lightuserdata which may escape already has the tag bits. */
o->u64 = *(uint64_t *)sps;
#endif
} else {
lua_assert(!irt_ispri(t)); /* PRI refs never have a spill slot. */
setgcrefi(o->gcr, *sps);
setitype(o, irt_toitype(t));
}
} else { /* Restore from register. */
Reg r = regsp_reg(rs);
lua_assert(ra_hasreg(r));
if (LJ_SOFTFP && (sn & SNAP_SOFTFPNUM)) {
o->u32.lo = (uint32_t)ex->gpr[r-RID_MIN_GPR];
} else if (irt_isinteger(t)) {
setintV(o, (int32_t)ex->gpr[r-RID_MIN_GPR]);
#if !LJ_SOFTFP
} else if (irt_isnum(t)) {
setnumV(o, ex->fpr[r-RID_MIN_FPR]);
#endif
#if LJ_64
} else if (irt_islightud(t)) {
/* 64 bit lightuserdata which may escape already has the tag bits. */
o->u64 = ex->gpr[r-RID_MIN_GPR];
#endif
} else {
if (!irt_ispri(t))
setgcrefi(o->gcr, ex->gpr[r-RID_MIN_GPR]);
setitype(o, irt_toitype(t));
}
}
if (LJ_SOFTFP && (sn & SNAP_SOFTFPNUM)) {
rs = (ir+1)->prev;
if (LJ_UNLIKELY(bloomtest(rfilt, ref+1)))
rs = snap_renameref(T, snapno, ref+1, rs);
o->u32.hi = (ra_hasspill(regsp_spill(rs))) ?
(uint32_t)*&ex->spill[regsp_spill(rs)] :
(uint32_t)ex->gpr[regsp_reg(rs)-RID_MIN_GPR];
}
}
if ((sn & (SNAP_CONT|SNAP_FRAME))) { /* Overwrite tag with frame link. */
o->fr.tp.ftsz = s != 0 ? (int32_t)*flinks-- : ftsz0;
L->base = o+1;
}
}
switch (bc_op(*pc)) {
case BC_CALLM: case BC_CALLMT: case BC_RETM: case BC_TSETM:
L->top = frame + snap->nslots;
break;
default:
L->top = curr_topL(L);
break;
}
lua_assert(map + nent == flinks);
return pc;
}
