示例#1
0
/* Mark non-sinkable allocations using single-pass backward propagation.
**
** Roots for the marking process are:
** - Some PHIs or snapshots (see below).
** - Non-PHI, non-constant values stored to PHI allocations.
** - All guards.
** - Any remaining loads not eliminated by store-to-load forwarding.
** - Stores with non-constant keys.
** - All stored values.
*/
static void sink_mark_ins(jit_State *J)
{
  IRIns *ir, *irlast = IR(J->cur.nins-1);
  for (ir = irlast ; ; ir--) {
    switch (ir->o) {
    case IR_BASE:
      return;  /* Finished. */
    case IR_CALLL:  /* IRCALL_lj_tab_len */
    case IR_ALOAD: case IR_HLOAD: case IR_XLOAD: case IR_TBAR:
      irt_setmark(IR(ir->op1)->t);  /* Mark ref for remaining loads. */
      break;
    case IR_FLOAD:
      if (irt_ismarked(ir->t) || ir->op2 == IRFL_TAB_META)
	irt_setmark(IR(ir->op1)->t);  /* Mark table for remaining loads. */
      break;
    case IR_ASTORE: case IR_HSTORE: case IR_FSTORE: case IR_XSTORE: {
      IRIns *ira = sink_checkalloc(J, ir);
      if (!ira || (irt_isphi(ira->t) && !sink_checkphi(J, ira, ir->op2)))
	irt_setmark(IR(ir->op1)->t);  /* Mark ineligible ref. */
      irt_setmark(IR(ir->op2)->t);  /* Mark stored value. */
      break;
      }
#if LJ_HASFFI
    case IR_CNEWI:
      if (irt_isphi(ir->t) &&
	  (!sink_checkphi(J, ir, ir->op2) ||
	   (LJ_32 && ir+1 < irlast && (ir+1)->o == IR_HIOP &&
	    !sink_checkphi(J, ir, (ir+1)->op2))))
	irt_setmark(ir->t);  /* Mark ineligible allocation. */
      /* fallthrough */
#endif
    case IR_USTORE:
      irt_setmark(IR(ir->op2)->t);  /* Mark stored value. */
      break;
#if LJ_HASFFI
    case IR_CALLXS:
#endif
    case IR_CALLS:
      irt_setmark(IR(ir->op1)->t);  /* Mark (potentially) stored values. */
      break;
    case IR_PHI: {
      IRIns *irl = IR(ir->op1), *irr = IR(ir->op2);
      irl->prev = irr->prev = 0;  /* Clear PHI value counts. */
      if (irl->o == irr->o &&
	  (irl->o == IR_TNEW || irl->o == IR_TDUP ||
	   (LJ_HASFFI && (irl->o == IR_CNEW || irl->o == IR_CNEWI))))
	break;
      irt_setmark(irl->t);
      irt_setmark(irr->t);
      break;
      }
    default:
      if (irt_ismarked(ir->t) || irt_isguard(ir->t)) {  /* Propagate mark. */
	if (ir->op1 >= REF_FIRST) irt_setmark(IR(ir->op1)->t);
	if (ir->op2 >= REF_FIRST) irt_setmark(IR(ir->op2)->t);
      }
      break;
    }
  }
}
示例#2
0
/* Sweep instructions and tag sunken allocations and stores. */
static void sink_sweep_ins(jit_State *J)
{
  IRIns *ir, *irbase = IR(REF_BASE);
  for (ir = IR(J->cur.nins-1) ; ir >= irbase; ir--) {
    switch (ir->o) {
    case IR_ASTORE: case IR_HSTORE: case IR_FSTORE: case IR_XSTORE: {
      IRIns *ira = sink_checkalloc(J, ir);
      if (ira && !irt_ismarked(ira->t)) {
	int delta = (int)(ir - ira);
	ir->prev = REGSP(RID_SINK, delta > 255 ? 255 : delta);
      } else {
	ir->prev = REGSP_INIT;
      }
      break;
      }
    case IR_NEWREF:
      if (!irt_ismarked(IR(ir->op1)->t)) {
	ir->prev = REGSP(RID_SINK, 0);
      } else {
	irt_clearmark(ir->t);
	ir->prev = REGSP_INIT;
      }
      break;
#if LJ_HASFFI
    case IR_CNEW: case IR_CNEWI:
#endif
    case IR_TNEW: case IR_TDUP:
      if (!irt_ismarked(ir->t)) {
	ir->t.irt &= ~IRT_GUARD;
	ir->prev = REGSP(RID_SINK, 0);
	J->cur.sinktags = 1;  /* Signal present SINK tags to assembler. */
      } else {
	irt_clearmark(ir->t);
	ir->prev = REGSP_INIT;
      }
      break;
    case IR_PHI: {
      IRIns *ira = IR(ir->op2);
      if (!irt_ismarked(ira->t) &&
	  (ira->o == IR_TNEW || ira->o == IR_TDUP ||
	   (LJ_HASFFI && (ira->o == IR_CNEW || ira->o == IR_CNEWI)))) {
	ir->prev = REGSP(RID_SINK, 0);
      } else {
	ir->prev = REGSP_INIT;
      }
      break;
      }
    default:
      irt_clearmark(ir->t);
      ir->prev = REGSP_INIT;
      break;
    }
  }
  for (ir = IR(J->cur.nk); ir < irbase; ir++) {
    irt_clearmark(ir->t);
    ir->prev = REGSP_INIT;
    if (irt_is64(ir->t) && ir->o != IR_KNULL)
      ir++;
  }
}