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Aegisub/vendor/luajit/src/lj_snap.c
Thomas Goyne 63f4bf1beb Switch from regular Lua to LuaJIT
2014-04-28 07:38:30 -07:00

865 lines
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/*
** Snapshot handling.
** Copyright (C) 2005-2014 Mike Pall. See Copyright Notice in luajit.h
*/
#define lj_snap_c
#define LUA_CORE
#include "lj_obj.h"
#if LJ_HASJIT
#include "lj_gc.h"
#include "lj_tab.h"
#include "lj_state.h"
#include "lj_frame.h"
#include "lj_bc.h"
#include "lj_ir.h"
#include "lj_jit.h"
#include "lj_iropt.h"
#include "lj_trace.h"
#include "lj_snap.h"
#include "lj_target.h"
#if LJ_HASFFI
#include "lj_ctype.h"
#include "lj_cdata.h"
#endif
/* Some local macros to save typing. Undef'd at the end. */
#define IR(ref) (&J->cur.ir[(ref)])
/* Pass IR on to next optimization in chain (FOLD). */
#define emitir(ot, a, b) (lj_ir_set(J, (ot), (a), (b)), lj_opt_fold(J))
/* Emit raw IR without passing through optimizations. */
#define emitir_raw(ot, a, b) (lj_ir_set(J, (ot), (a), (b)), lj_ir_emit(J))
/* -- Snapshot buffer allocation ------------------------------------------ */
/* Grow snapshot buffer. */
void lj_snap_grow_buf_(jit_State *J, MSize need)
{
MSize maxsnap = (MSize)J->param[JIT_P_maxsnap];
if (need > maxsnap)
lj_trace_err(J, LJ_TRERR_SNAPOV);
lj_mem_growvec(J->L, J->snapbuf, J->sizesnap, maxsnap, SnapShot);
J->cur.snap = J->snapbuf;
}
/* Grow snapshot map buffer. */
void lj_snap_grow_map_(jit_State *J, MSize need)
{
if (need < 2*J->sizesnapmap)
need = 2*J->sizesnapmap;
else if (need < 64)
need = 64;
J->snapmapbuf = (SnapEntry *)lj_mem_realloc(J->L, J->snapmapbuf,
J->sizesnapmap*sizeof(SnapEntry), need*sizeof(SnapEntry));
J->cur.snapmap = J->snapmapbuf;
J->sizesnapmap = need;
}
/* -- Snapshot generation ------------------------------------------------- */
/* Add all modified slots to the snapshot. */
static MSize snapshot_slots(jit_State *J, SnapEntry *map, BCReg nslots)
{
IRRef retf = J->chain[IR_RETF]; /* Limits SLOAD restore elimination. */
BCReg s;
MSize n = 0;
for (s = 0; s < nslots; s++) {
TRef tr = J->slot[s];
IRRef ref = tref_ref(tr);
if (ref) {
SnapEntry sn = SNAP_TR(s, tr);
IRIns *ir = IR(ref);
if (!(sn & (SNAP_CONT|SNAP_FRAME)) &&
ir->o == IR_SLOAD && ir->op1 == s && ref > retf) {
/* No need to snapshot unmodified non-inherited slots. */
if (!(ir->op2 & IRSLOAD_INHERIT))
continue;
/* No need to restore readonly slots and unmodified non-parent slots. */
if (!(LJ_DUALNUM && (ir->op2 & IRSLOAD_CONVERT)) &&
(ir->op2 & (IRSLOAD_READONLY|IRSLOAD_PARENT)) != IRSLOAD_PARENT)
sn |= SNAP_NORESTORE;
}
if (LJ_SOFTFP && irt_isnum(ir->t))
sn |= SNAP_SOFTFPNUM;
map[n++] = sn;
}
}
return n;
}
/* 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;
cTValue *ftop = frame + funcproto(frame_func(frame))->framesize;
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);
if (frame + funcproto(frame_func(frame))->framesize > ftop)
ftop = frame + funcproto(frame_func(frame))->framesize;
} 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));
return (BCReg)(ftop - lim);
}
/* Take a snapshot of the current stack. */
static void snapshot_stack(jit_State *J, SnapShot *snap, MSize nsnapmap)
{
BCReg nslots = J->baseslot + J->maxslot;
MSize nent;
SnapEntry *p;
/* Conservative estimate. */
lj_snap_grow_map(J, nsnapmap + nslots + (MSize)J->framedepth+1);
p = &J->cur.snapmap[nsnapmap];
nent = snapshot_slots(J, p, nslots);
snap->topslot = (uint8_t)snapshot_framelinks(J, p + nent);
snap->mapofs = (uint16_t)nsnapmap;
snap->ref = (IRRef1)J->cur.nins;
snap->nent = (uint8_t)nent;
snap->nslots = (uint8_t)nslots;
snap->count = 0;
J->cur.nsnapmap = (uint16_t)(nsnapmap + nent + 1 + J->framedepth);
}
/* Add or merge a snapshot. */
void lj_snap_add(jit_State *J)
{
MSize nsnap = J->cur.nsnap;
MSize nsnapmap = J->cur.nsnapmap;
/* Merge if no ins. inbetween or if requested and no guard inbetween. */
if (J->mergesnap ? !irt_isguard(J->guardemit) :
(nsnap > 0 && J->cur.snap[nsnap-1].ref == J->cur.nins)) {
if (nsnap == 1) { /* But preserve snap #0 PC. */
emitir_raw(IRT(IR_NOP, IRT_NIL), 0, 0);
goto nomerge;
}
nsnapmap = J->cur.snap[--nsnap].mapofs;
} else {
nomerge:
lj_snap_grow_buf(J, nsnap+1);
J->cur.nsnap = (uint16_t)(nsnap+1);
}
J->mergesnap = 0;
J->guardemit.irt = 0;
snapshot_stack(J, &J->cur.snap[nsnap], nsnapmap);
}
/* -- Snapshot modification ----------------------------------------------- */
#define SNAP_USEDEF_SLOTS (LJ_MAX_JSLOTS+LJ_STACK_EXTRA)
/* Find unused slots with reaching-definitions bytecode data-flow analysis. */
static BCReg snap_usedef(jit_State *J, uint8_t *udf,
const BCIns *pc, BCReg maxslot)
{
BCReg s;
GCobj *o;
if (maxslot == 0) return 0;
#ifdef LUAJIT_USE_VALGRIND
/* Avoid errors for harmless reads beyond maxslot. */
memset(udf, 1, SNAP_USEDEF_SLOTS);
#else
memset(udf, 1, maxslot);
#endif
/* Treat open upvalues as used. */
o = gcref(J->L->openupval);
while (o) {
if (uvval(gco2uv(o)) < J->L->base) break;
udf[uvval(gco2uv(o)) - J->L->base] = 0;
o = gcref(o->gch.nextgc);
}
#define USE_SLOT(s) udf[(s)] &= ~1
#define DEF_SLOT(s) udf[(s)] *= 3
/* Scan through following bytecode and check for uses/defs. */
lua_assert(pc >= proto_bc(J->pt) && pc < proto_bc(J->pt) + J->pt->sizebc);
for (;;) {
BCIns ins = *pc++;
BCOp op = bc_op(ins);
switch (bcmode_b(op)) {
case BCMvar: USE_SLOT(bc_b(ins)); break;
default: break;
}
switch (bcmode_c(op)) {
case BCMvar: USE_SLOT(bc_c(ins)); break;
case BCMrbase:
lua_assert(op == BC_CAT);
for (s = bc_b(ins); s <= bc_c(ins); s++) USE_SLOT(s);
for (; s < maxslot; s++) DEF_SLOT(s);
break;
case BCMjump:
handle_jump: {
BCReg minslot = bc_a(ins);
if (op >= BC_FORI && op <= BC_JFORL) minslot += FORL_EXT;
else if (op >= BC_ITERL && op <= BC_JITERL) minslot += bc_b(pc[-2])-1;
else if (op == BC_UCLO) { pc += bc_j(ins); break; }
for (s = minslot; s < maxslot; s++) DEF_SLOT(s);
return minslot < maxslot ? minslot : maxslot;
}
case BCMlit:
if (op == BC_JFORL || op == BC_JITERL || op == BC_JLOOP) {
goto handle_jump;
} else if (bc_isret(op)) {
BCReg top = op == BC_RETM ? maxslot : (bc_a(ins) + bc_d(ins)-1);
for (s = 0; s < bc_a(ins); s++) DEF_SLOT(s);
for (; s < top; s++) USE_SLOT(s);
for (; s < maxslot; s++) DEF_SLOT(s);
return 0;
}
break;
case BCMfunc: return maxslot; /* NYI: will abort, anyway. */
default: break;
}
switch (bcmode_a(op)) {
case BCMvar: USE_SLOT(bc_a(ins)); break;
case BCMdst:
if (!(op == BC_ISTC || op == BC_ISFC)) DEF_SLOT(bc_a(ins));
break;
case BCMbase:
if (op >= BC_CALLM && op <= BC_VARG) {
BCReg top = (op == BC_CALLM || op == BC_CALLMT || bc_c(ins) == 0) ?
maxslot : (bc_a(ins) + bc_c(ins));
s = bc_a(ins) - ((op == BC_ITERC || op == BC_ITERN) ? 3 : 0);
for (; s < top; s++) USE_SLOT(s);
for (; s < maxslot; s++) DEF_SLOT(s);
if (op == BC_CALLT || op == BC_CALLMT) {
for (s = 0; s < bc_a(ins); s++) DEF_SLOT(s);
return 0;
}
} else if (op == BC_KNIL) {
for (s = bc_a(ins); s <= bc_d(ins); s++) DEF_SLOT(s);
} else if (op == BC_TSETM) {
for (s = bc_a(ins)-1; s < maxslot; s++) USE_SLOT(s);
}
break;
default: break;
}
lua_assert(pc >= proto_bc(J->pt) && pc < proto_bc(J->pt) + J->pt->sizebc);
}
#undef USE_SLOT
#undef DEF_SLOT
return 0; /* unreachable */
}
/* Purge dead slots before the next snapshot. */
void lj_snap_purge(jit_State *J)
{
uint8_t udf[SNAP_USEDEF_SLOTS];
BCReg maxslot = J->maxslot;
BCReg s = snap_usedef(J, udf, J->pc, maxslot);
for (; s < maxslot; s++)
if (udf[s] != 0)
J->base[s] = 0; /* Purge dead slots. */
}
/* Shrink last snapshot. */
void lj_snap_shrink(jit_State *J)
{
SnapShot *snap = &J->cur.snap[J->cur.nsnap-1];
SnapEntry *map = &J->cur.snapmap[snap->mapofs];
MSize n, m, nlim, nent = snap->nent;
uint8_t udf[SNAP_USEDEF_SLOTS];
BCReg maxslot = J->maxslot;
BCReg minslot = snap_usedef(J, udf, snap_pc(map[nent]), maxslot);
BCReg baseslot = J->baseslot;
maxslot += baseslot;
minslot += baseslot;
snap->nslots = (uint8_t)maxslot;
for (n = m = 0; n < nent; n++) { /* Remove unused slots from snapshot. */
BCReg s = snap_slot(map[n]);
if (s < minslot || (s < maxslot && udf[s-baseslot] == 0))
map[m++] = map[n]; /* Only copy used slots. */
}
snap->nent = (uint8_t)m;
nlim = J->cur.nsnapmap - snap->mapofs - 1;
while (n <= nlim) map[m++] = map[n++]; /* Move PC + frame links down. */
J->cur.nsnapmap = (uint16_t)(snap->mapofs + m); /* Free up space in map. */
}
/* -- Snapshot access ----------------------------------------------------- */
/* Initialize a Bloom Filter with all renamed refs.
** There are very few renames (often none), so the filter has
** very few bits set. This makes it suitable for negative filtering.
*/
static BloomFilter snap_renamefilter(GCtrace *T, SnapNo lim)
{
BloomFilter rfilt = 0;
IRIns *ir;
for (ir = &T->ir[T->nins-1]; ir->o == IR_RENAME; ir--)
if (ir->op2 <= lim)
bloomset(rfilt, ir->op1);
return rfilt;
}
/* Process matching renames to find the original RegSP. */
static RegSP snap_renameref(GCtrace *T, SnapNo lim, IRRef ref, RegSP rs)
{
IRIns *ir;
for (ir = &T->ir[T->nins-1]; ir->o == IR_RENAME; ir--)
if (ir->op1 == ref && ir->op2 <= lim)
rs = ir->prev;
return rs;
}
/* Copy RegSP from parent snapshot to the parent links of the IR. */
IRIns *lj_snap_regspmap(GCtrace *T, SnapNo snapno, IRIns *ir)
{
SnapShot *snap = &T->snap[snapno];
SnapEntry *map = &T->snapmap[snap->mapofs];
BloomFilter rfilt = snap_renamefilter(T, snapno);
MSize n = 0;
IRRef ref = 0;
for ( ; ; ir++) {
uint32_t rs;
if (ir->o == IR_SLOAD) {
if (!(ir->op2 & IRSLOAD_PARENT)) break;
for ( ; ; n++) {
lua_assert(n < snap->nent);
if (snap_slot(map[n]) == ir->op1) {
ref = snap_ref(map[n++]);
break;
}
}
} else if (LJ_SOFTFP && ir->o == IR_HIOP) {
ref++;
} else if (ir->o == IR_PVAL) {
ref = ir->op1 + REF_BIAS;
} else {
break;
}
rs = T->ir[ref].prev;
if (bloomtest(rfilt, ref))
rs = snap_renameref(T, snapno, ref, rs);
ir->prev = (uint16_t)rs;
lua_assert(regsp_used(rs));
}
return ir;
}
/* -- Snapshot replay ----------------------------------------------------- */
/* Replay constant from parent trace. */
static TRef snap_replay_const(jit_State *J, IRIns *ir)
{
/* Only have to deal with constants that can occur in stack slots. */
switch ((IROp)ir->o) {
case IR_KPRI: return TREF_PRI(irt_type(ir->t));
case IR_KINT: return lj_ir_kint(J, ir->i);
case IR_KGC: return lj_ir_kgc(J, ir_kgc(ir), irt_t(ir->t));
case IR_KNUM: return lj_ir_k64(J, IR_KNUM, ir_knum(ir));
case IR_KINT64: return lj_ir_k64(J, IR_KINT64, ir_kint64(ir));
case IR_KPTR: return lj_ir_kptr(J, ir_kptr(ir)); /* Continuation. */
default: lua_assert(0); return TREF_NIL; break;
}
}
/* De-duplicate parent reference. */
static TRef snap_dedup(jit_State *J, SnapEntry *map, MSize nmax, IRRef ref)
{
MSize j;
for (j = 0; j < nmax; j++)
if (snap_ref(map[j]) == ref)
return J->slot[snap_slot(map[j])] & ~(SNAP_CONT|SNAP_FRAME);
return 0;
}
/* Emit parent reference with de-duplication. */
static TRef snap_pref(jit_State *J, GCtrace *T, SnapEntry *map, MSize nmax,
BloomFilter seen, IRRef ref)
{
IRIns *ir = &T->ir[ref];
TRef tr;
if (irref_isk(ref))
tr = snap_replay_const(J, ir);
else if (!regsp_used(ir->prev))
tr = 0;
else if (!bloomtest(seen, ref) || (tr = snap_dedup(J, map, nmax, ref)) == 0)
tr = emitir(IRT(IR_PVAL, irt_type(ir->t)), ref - REF_BIAS, 0);
return tr;
}
/* Check whether a sunk store corresponds to an allocation. Slow path. */
static int snap_sunk_store2(jit_State *J, IRIns *ira, IRIns *irs)
{
if (irs->o == IR_ASTORE || irs->o == IR_HSTORE ||
irs->o == IR_FSTORE || irs->o == IR_XSTORE) {
IRIns *irk = IR(irs->op1);
if (irk->o == IR_AREF || irk->o == IR_HREFK)
irk = IR(irk->op1);
return (IR(irk->op1) == ira);
}
return 0;
}
/* Check whether a sunk store corresponds to an allocation. Fast path. */
static LJ_AINLINE int snap_sunk_store(jit_State *J, IRIns *ira, IRIns *irs)
{
if (irs->s != 255)
return (ira + irs->s == irs); /* Fast check. */
return snap_sunk_store2(J, ira, irs);
}
/* Replay snapshot state to setup side trace. */
void lj_snap_replay(jit_State *J, GCtrace *T)
{
SnapShot *snap = &T->snap[J->exitno];
SnapEntry *map = &T->snapmap[snap->mapofs];
MSize n, nent = snap->nent;
BloomFilter seen = 0;
int pass23 = 0;
J->framedepth = 0;
/* Emit IR for slots inherited from parent snapshot. */
for (n = 0; n < nent; n++) {
SnapEntry sn = map[n];
BCReg s = snap_slot(sn);
IRRef ref = snap_ref(sn);
IRIns *ir = &T->ir[ref];
TRef tr;
/* The bloom filter avoids O(nent^2) overhead for de-duping slots. */
if (bloomtest(seen, ref) && (tr = snap_dedup(J, map, n, ref)) != 0)
goto setslot;
bloomset(seen, ref);
if (irref_isk(ref)) {
tr = snap_replay_const(J, ir);
} else if (!regsp_used(ir->prev)) {
pass23 = 1;
lua_assert(s != 0);
tr = s;
} else {
IRType t = irt_type(ir->t);
uint32_t mode = IRSLOAD_INHERIT|IRSLOAD_PARENT;
if (LJ_SOFTFP && (sn & SNAP_SOFTFPNUM)) t = IRT_NUM;
if (ir->o == IR_SLOAD) mode |= (ir->op2 & IRSLOAD_READONLY);
tr = emitir_raw(IRT(IR_SLOAD, t), s, mode);
}
setslot:
J->slot[s] = tr | (sn&(SNAP_CONT|SNAP_FRAME)); /* Same as TREF_* flags. */
J->framedepth += ((sn & (SNAP_CONT|SNAP_FRAME)) && s);
if ((sn & SNAP_FRAME))
J->baseslot = s+1;
}
if (pass23) {
IRIns *irlast = &T->ir[snap->ref];
pass23 = 0;
/* Emit dependent PVALs. */
for (n = 0; n < nent; n++) {
SnapEntry sn = map[n];
IRRef refp = snap_ref(sn);
IRIns *ir = &T->ir[refp];
if (regsp_reg(ir->r) == RID_SUNK) {
if (J->slot[snap_slot(sn)] != snap_slot(sn)) continue;
pass23 = 1;
lua_assert(ir->o == IR_TNEW || ir->o == IR_TDUP ||
ir->o == IR_CNEW || ir->o == IR_CNEWI);
if (ir->op1 >= T->nk) snap_pref(J, T, map, nent, seen, ir->op1);
if (ir->op2 >= T->nk) snap_pref(J, T, map, nent, seen, ir->op2);
if (LJ_HASFFI && ir->o == IR_CNEWI) {
if (LJ_32 && refp+1 < T->nins && (ir+1)->o == IR_HIOP)
snap_pref(J, T, map, nent, seen, (ir+1)->op2);
} else {
IRIns *irs;
for (irs = ir+1; irs < irlast; irs++)
if (irs->r == RID_SINK && snap_sunk_store(J, ir, irs)) {
if (snap_pref(J, T, map, nent, seen, irs->op2) == 0)
snap_pref(J, T, map, nent, seen, T->ir[irs->op2].op1);
else if ((LJ_SOFTFP || (LJ_32 && LJ_HASFFI)) &&
irs+1 < irlast && (irs+1)->o == IR_HIOP)
snap_pref(J, T, map, nent, seen, (irs+1)->op2);
}
}
} else if (!irref_isk(refp) && !regsp_used(ir->prev)) {
lua_assert(ir->o == IR_CONV && ir->op2 == IRCONV_NUM_INT);
J->slot[snap_slot(sn)] = snap_pref(J, T, map, nent, seen, ir->op1);
}
}
/* Replay sunk instructions. */
for (n = 0; pass23 && n < nent; n++) {
SnapEntry sn = map[n];
IRRef refp = snap_ref(sn);
IRIns *ir = &T->ir[refp];
if (regsp_reg(ir->r) == RID_SUNK) {
TRef op1, op2;
if (J->slot[snap_slot(sn)] != snap_slot(sn)) { /* De-dup allocs. */
J->slot[snap_slot(sn)] = J->slot[J->slot[snap_slot(sn)]];
continue;
}
op1 = ir->op1;
if (op1 >= T->nk) op1 = snap_pref(J, T, map, nent, seen, op1);
op2 = ir->op2;
if (op2 >= T->nk) op2 = snap_pref(J, T, map, nent, seen, op2);
if (LJ_HASFFI && ir->o == IR_CNEWI) {
if (LJ_32 && refp+1 < T->nins && (ir+1)->o == IR_HIOP) {
lj_needsplit(J); /* Emit joining HIOP. */
op2 = emitir_raw(IRT(IR_HIOP, IRT_I64), op2,
snap_pref(J, T, map, nent, seen, (ir+1)->op2));
}
J->slot[snap_slot(sn)] = emitir(ir->ot, op1, op2);
} else {
IRIns *irs;
TRef tr = emitir(ir->ot, op1, op2);
J->slot[snap_slot(sn)] = tr;
for (irs = ir+1; irs < irlast; irs++)
if (irs->r == RID_SINK && snap_sunk_store(J, ir, irs)) {
IRIns *irr = &T->ir[irs->op1];
TRef val, key = irr->op2, tmp = tr;
if (irr->o != IR_FREF) {
IRIns *irk = &T->ir[key];
if (irr->o == IR_HREFK)
key = lj_ir_kslot(J, snap_replay_const(J, &T->ir[irk->op1]),
irk->op2);
else
key = snap_replay_const(J, irk);
if (irr->o == IR_HREFK || irr->o == IR_AREF) {
IRIns *irf = &T->ir[irr->op1];
tmp = emitir(irf->ot, tmp, irf->op2);
}
}
tmp = emitir(irr->ot, tmp, key);
val = snap_pref(J, T, map, nent, seen, irs->op2);
if (val == 0) {
IRIns *irc = &T->ir[irs->op2];
lua_assert(irc->o == IR_CONV && irc->op2 == IRCONV_NUM_INT);
val = snap_pref(J, T, map, nent, seen, irc->op1);
val = emitir(IRTN(IR_CONV), val, IRCONV_NUM_INT);
} else if ((LJ_SOFTFP || (LJ_32 && LJ_HASFFI)) &&
irs+1 < irlast && (irs+1)->o == IR_HIOP) {
IRType t = IRT_I64;
if (LJ_SOFTFP && irt_type((irs+1)->t) == IRT_SOFTFP)
t = IRT_NUM;
lj_needsplit(J);
if (irref_isk(irs->op2) && irref_isk((irs+1)->op2)) {
uint64_t k = (uint32_t)T->ir[irs->op2].i +
((uint64_t)T->ir[(irs+1)->op2].i << 32);
val = lj_ir_k64(J, t == IRT_I64 ? IR_KINT64 : IR_KNUM,
lj_ir_k64_find(J, k));
} else {
val = emitir_raw(IRT(IR_HIOP, t), val,
snap_pref(J, T, map, nent, seen, (irs+1)->op2));
}
tmp = emitir(IRT(irs->o, t), tmp, val);
continue;
}
tmp = emitir(irs->ot, tmp, val);
} else if (LJ_HASFFI && irs->o == IR_XBAR && ir->o == IR_CNEW) {
emitir(IRT(IR_XBAR, IRT_NIL), 0, 0);
}
}
}
}
}
J->base = J->slot + J->baseslot;
J->maxslot = snap->nslots - J->baseslot;
lj_snap_add(J);
if (pass23) /* Need explicit GC step _after_ initial snapshot. */
emitir_raw(IRTG(IR_GCSTEP, IRT_NIL), 0, 0);
}
/* -- Snapshot restore ---------------------------------------------------- */
static void snap_unsink(jit_State *J, GCtrace *T, ExitState *ex,
SnapNo snapno, BloomFilter rfilt,
IRIns *ir, TValue *o);
/* Restore a value from the trace exit state. */
static void snap_restoreval(jit_State *J, GCtrace *T, ExitState *ex,
SnapNo snapno, BloomFilter rfilt,
IRRef ref, TValue *o)
{
IRIns *ir = &T->ir[ref];
IRType1 t = ir->t;
RegSP rs = ir->prev;
if (irref_isk(ref)) { /* Restore constant slot. */
lj_ir_kvalue(J->L, o, ir);
return;
}
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 (irt_isinteger(t)) {
setintV(o, *sps);
#if !LJ_SOFTFP
} else if (irt_isnum(t)) {
o->u64 = *(uint64_t *)sps;
#endif
} else if (LJ_64 && irt_islightud(t)) {
/* 64 bit lightuserdata which may escape already has the tag bits. */
o->u64 = *(uint64_t *)sps;
} 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);
if (ra_noreg(r)) {
lua_assert(ir->o == IR_CONV && ir->op2 == IRCONV_NUM_INT);
snap_restoreval(J, T, ex, snapno, rfilt, ir->op1, o);
if (LJ_DUALNUM) setnumV(o, (lua_Number)intV(o));
return;
} 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
} else if (LJ_64 && irt_islightud(t)) {
/* 64 bit lightuserdata which may escape already has the tag bits. */
o->u64 = ex->gpr[r-RID_MIN_GPR];
} else {
if (!irt_ispri(t))
setgcrefi(o->gcr, ex->gpr[r-RID_MIN_GPR]);
setitype(o, irt_toitype(t));
}
}
}
#if LJ_HASFFI
/* Restore raw data from the trace exit state. */
static void snap_restoredata(GCtrace *T, ExitState *ex,
SnapNo snapno, BloomFilter rfilt,
IRRef ref, void *dst, CTSize sz)
{
IRIns *ir = &T->ir[ref];
RegSP rs = ir->prev;
int32_t *src;
uint64_t tmp;
if (irref_isk(ref)) {
if (ir->o == IR_KNUM || ir->o == IR_KINT64) {
src = mref(ir->ptr, int32_t);
} else if (sz == 8) {
tmp = (uint64_t)(uint32_t)ir->i;
src = (int32_t *)&tmp;
} else {
src = &ir->i;
}
} else {
if (LJ_UNLIKELY(bloomtest(rfilt, ref)))
rs = snap_renameref(T, snapno, ref, rs);
if (ra_hasspill(regsp_spill(rs))) {
src = &ex->spill[regsp_spill(rs)];
if (sz == 8 && !irt_is64(ir->t)) {
tmp = (uint64_t)(uint32_t)*src;
src = (int32_t *)&tmp;
}
} else {
Reg r = regsp_reg(rs);
if (ra_noreg(r)) {
/* Note: this assumes CNEWI is never used for SOFTFP split numbers. */
lua_assert(sz == 8 && ir->o == IR_CONV && ir->op2 == IRCONV_NUM_INT);
snap_restoredata(T, ex, snapno, rfilt, ir->op1, dst, 4);
*(lua_Number *)dst = (lua_Number)*(int32_t *)dst;
return;
}
src = (int32_t *)&ex->gpr[r-RID_MIN_GPR];
#if !LJ_SOFTFP
if (r >= RID_MAX_GPR) {
src = (int32_t *)&ex->fpr[r-RID_MIN_FPR];
#if LJ_TARGET_PPC
if (sz == 4) { /* PPC FPRs are always doubles. */
*(float *)dst = (float)*(double *)src;
return;
}
#else
if (LJ_BE && sz == 4) src++;
#endif
}
#endif
}
}
lua_assert(sz == 1 || sz == 2 || sz == 4 || sz == 8);
if (sz == 4) *(int32_t *)dst = *src;
else if (sz == 8) *(int64_t *)dst = *(int64_t *)src;
else if (sz == 1) *(int8_t *)dst = (int8_t)*src;
else *(int16_t *)dst = (int16_t)*src;
}
#endif
/* Unsink allocation from the trace exit state. Unsink sunk stores. */
static void snap_unsink(jit_State *J, GCtrace *T, ExitState *ex,
SnapNo snapno, BloomFilter rfilt,
IRIns *ir, TValue *o)
{
lua_assert(ir->o == IR_TNEW || ir->o == IR_TDUP ||
ir->o == IR_CNEW || ir->o == IR_CNEWI);
#if LJ_HASFFI
if (ir->o == IR_CNEW || ir->o == IR_CNEWI) {
CTState *cts = ctype_cts(J->L);
CTypeID id = (CTypeID)T->ir[ir->op1].i;
CTSize sz = lj_ctype_size(cts, id);
GCcdata *cd = lj_cdata_new(cts, id, sz);
setcdataV(J->L, o, cd);
if (ir->o == IR_CNEWI) {
uint8_t *p = (uint8_t *)cdataptr(cd);
lua_assert(sz == 4 || sz == 8);
if (LJ_32 && sz == 8 && ir+1 < T->ir + T->nins && (ir+1)->o == IR_HIOP) {
snap_restoredata(T, ex, snapno, rfilt, (ir+1)->op2, LJ_LE?p+4:p, 4);
if (LJ_BE) p += 4;
sz = 4;
}
snap_restoredata(T, ex, snapno, rfilt, ir->op2, p, sz);
} else {
IRIns *irs, *irlast = &T->ir[T->snap[snapno].ref];
for (irs = ir+1; irs < irlast; irs++)
if (irs->r == RID_SINK && snap_sunk_store(J, ir, irs)) {
IRIns *iro = &T->ir[T->ir[irs->op1].op2];
uint8_t *p = (uint8_t *)cd;
CTSize szs;
lua_assert(irs->o == IR_XSTORE && T->ir[irs->op1].o == IR_ADD);
lua_assert(iro->o == IR_KINT || iro->o == IR_KINT64);
if (irt_is64(irs->t)) szs = 8;
else if (irt_isi8(irs->t) || irt_isu8(irs->t)) szs = 1;
else if (irt_isi16(irs->t) || irt_isu16(irs->t)) szs = 2;
else szs = 4;
if (LJ_64 && iro->o == IR_KINT64)
p += (int64_t)ir_k64(iro)->u64;
else
p += iro->i;
lua_assert(p >= (uint8_t *)cdataptr(cd) &&
p + szs <= (uint8_t *)cdataptr(cd) + sz);
if (LJ_32 && irs+1 < T->ir + T->nins && (irs+1)->o == IR_HIOP) {
lua_assert(szs == 4);
snap_restoredata(T, ex, snapno, rfilt, (irs+1)->op2, LJ_LE?p+4:p,4);
if (LJ_BE) p += 4;
}
snap_restoredata(T, ex, snapno, rfilt, irs->op2, p, szs);
}
}
} else
#endif
{
IRIns *irs, *irlast;
GCtab *t = ir->o == IR_TNEW ? lj_tab_new(J->L, ir->op1, ir->op2) :
lj_tab_dup(J->L, ir_ktab(&T->ir[ir->op1]));
settabV(J->L, o, t);
irlast = &T->ir[T->snap[snapno].ref];
for (irs = ir+1; irs < irlast; irs++)
if (irs->r == RID_SINK && snap_sunk_store(J, ir, irs)) {
IRIns *irk = &T->ir[irs->op1];
TValue tmp, *val;
lua_assert(irs->o == IR_ASTORE || irs->o == IR_HSTORE ||
irs->o == IR_FSTORE);
if (irk->o == IR_FREF) {
lua_assert(irk->op2 == IRFL_TAB_META);
snap_restoreval(J, T, ex, snapno, rfilt, irs->op2, &tmp);
/* NOBARRIER: The table is new (marked white). */
setgcref(t->metatable, obj2gco(tabV(&tmp)));
} else {
irk = &T->ir[irk->op2];
if (irk->o == IR_KSLOT) irk = &T->ir[irk->op1];
lj_ir_kvalue(J->L, &tmp, irk);
val = lj_tab_set(J->L, t, &tmp);
/* NOBARRIER: The table is new (marked white). */
snap_restoreval(J, T, ex, snapno, rfilt, irs->op2, val);
if (LJ_SOFTFP && irs+1 < T->ir + T->nins && (irs+1)->o == IR_HIOP) {
snap_restoreval(J, T, ex, snapno, rfilt, (irs+1)->op2, &tmp);
val->u32.hi = tmp.u32.lo;
}
}
}
}
}
/* 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];
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))) {
/* Overwrite tag with frame link. */
o->fr.tp.ftsz = 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;
}
#undef IR
#undef emitir_raw
#undef emitir
#endif
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