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Implement down-recursion.

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This commit is contained in:
Mike Pall
2010-03-01 06:45:30 +01:00
parent 69ea553024
commit e7b737aa12
7 changed files with 114 additions and 13 deletions
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41
src/lj_record.c
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@@ -522,6 +522,29 @@ static void rec_tailcall(jit_State *J, BCReg func, ptrdiff_t nargs)
lj_trace_err(J, LJ_TRERR_LUNROLL);
}
/* Check unroll limits for down-recursion. */
static int check_downrec_unroll(jit_State *J, GCproto *pt)
{
IRRef ptref;
for (ptref = J->chain[IR_KGC]; ptref; ptref = IR(ptref)->prev)
if (ir_kgc(IR(ptref)) == obj2gco(pt)) {
int count = 0;
IRRef ref;
for (ref = J->chain[IR_RETF]; ref; ref = IR(ref)->prev)
if (IR(ref)->op1 == ptref)
count++;
if (count) {
if (J->pc == J->startpc) {
if (count + J->tailcalled > J->param[JIT_P_recunroll])
return 1;
} else {
lj_trace_err(J, LJ_TRERR_DOWNREC);
}
}
}
return 0;
}
/* Record return. */
static void rec_ret(jit_State *J, BCReg rbase, ptrdiff_t gotresults)
{
@@ -545,6 +568,15 @@ static void rec_ret(jit_State *J, BCReg rbase, ptrdiff_t gotresults)
BCIns callins = *(frame_pc(frame)-1);
ptrdiff_t nresults = bc_b(callins) ? (ptrdiff_t)bc_b(callins)-1 :gotresults;
BCReg cbase = bc_a(callins);
GCproto *pt = funcproto(frame_func(frame - (cbase+1)));
if (J->pt && frame == J->L->base - 1) {
if (J->framedepth == 0 && check_downrec_unroll(J, pt)) {
J->maxslot = rbase + nresults;
rec_stop(J, J->curtrace); /* Down-recursion. */
return;
}
lj_snap_add(J);
}
for (i = 0; i < nresults; i++) /* Adjust results. */
J->base[i-1] = i < gotresults ? J->base[rbase+i] : TREF_NIL;
J->maxslot = cbase+(BCReg)nresults;
@@ -553,11 +585,10 @@ static void rec_ret(jit_State *J, BCReg rbase, ptrdiff_t gotresults)
lua_assert(J->baseslot > cbase+1);
J->baseslot -= cbase+1;
J->base -= cbase+1;
} else if (J->parent == 0) {
} else if (J->parent == 0 && !bc_isret(bc_op(J->cur.startins))) {
/* Return to lower frame would leave the loop in a root trace. */
lj_trace_err(J, LJ_TRERR_LLEAVE);
} else { /* Return to lower frame. Guard for the target we return to. */
GCproto *pt = funcproto(frame_func(frame - (cbase+1)));
TRef trpt = lj_ir_kgc(J, obj2gco(pt), IRT_PROTO);
TRef trpc = lj_ir_kptr(J, (void *)frame_pc(frame));
emitir(IRTG(IR_RETF, IRT_PTR), trpt, trpc);
@@ -2285,6 +2316,12 @@ static const BCIns *rec_setup_root(jit_State *J)
J->maxslot = ra;
pc++;
break;
case BC_RET:
case BC_RET0:
case BC_RET1:
/* No bytecode range check for down-recursive root traces. */
J->maxslot = ra + bc_d(ins);
break;
case BC_FUNCF:
/* No bytecode range check for root traces started by a hot call. */
J->maxslot = J->pt->numparams;