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Don't eliminate SLOAD restores across RETF.

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Move restore-elimination logic into snapshot_slots().
This commit is contained in:
Mike Pall 2010-02-23 03:08:49 +01:00
parent f751cd1d6f
commit c1362dcac9
3 changed files with 13 additions and 6 deletions
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4
src/lj_asm.c
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@ -2581,9 +2581,7 @@ static void asm_stack_restore(ASMState *as, SnapShot *snap)
int32_t ofs = 8*((int32_t)s-1);
IRRef ref = snap_ref(sn);
IRIns *ir = IR(ref);
/* No need to restore readonly slots and unmodified non-parent slots. */
if (ir->o == IR_SLOAD && ir->op1 == s &&
(ir->op2 & (IRSLOAD_READONLY|IRSLOAD_PARENT)) != IRSLOAD_PARENT)
if ((sn & SNAP_NORESTORE))
continue;
if (irt_isnum(ir->t)) {
Reg src = ra_alloc1(as, ref, RSET_FPR);

1
src/lj_jit.h
View File

@ -125,6 +125,7 @@ typedef uint32_t SnapEntry;
#define SNAP_FRAME 0x010000 /* Frame slot. */
#define SNAP_CONT 0x020000 /* Continuation slot. */
#define SNAP_NORESTORE 0x040000 /* No need to restore slot. */
LJ_STATIC_ASSERT(SNAP_FRAME == TREF_FRAME);
LJ_STATIC_ASSERT(SNAP_CONT == TREF_CONT);

14
src/lj_snap.c
View File

@ -53,16 +53,24 @@ void lj_snap_grow_map_(jit_State *J, MSize need)
/* 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 (!(ir->o == IR_SLOAD && ir->op1 == s &&
!(ir->op2 & IRSLOAD_INHERIT)))
map[n++] = SNAP_TR(s, tr);
if (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 ((ir->op2 & (IRSLOAD_READONLY|IRSLOAD_PARENT)) != IRSLOAD_PARENT)
sn |= SNAP_NORESTORE;
}
map[n++] = sn;
}
}
return n;