private void processFixedGuardAndMerge(
FixedGuardNode fixedGuard,
PhaseContext context,
CompareNode compare,
ValueNode x,
ValuePhiNode xPhi,
ValueNode y,
ValuePhiNode yPhi,
AbstractMergeNode merge) {
List<EndNode> mergePredecessors = merge.cfgPredecessors().snapshot();
for (int i = 0; i < mergePredecessors.size(); ++i) {
AbstractEndNode mergePredecessor = mergePredecessors.get(i);
if (!mergePredecessor.isAlive()) {
break;
}
Constant xs;
if (xPhi == null) {
xs = x.asConstant();
} else {
xs = xPhi.valueAt(mergePredecessor).asConstant();
}
Constant ys;
if (yPhi == null) {
ys = y.asConstant();
} else {
ys = yPhi.valueAt(mergePredecessor).asConstant();
}
if (xs != null
&& ys != null
&& compare
.condition()
.foldCondition(xs, ys, context.getConstantReflection(), compare.unorderedIsTrue())
== fixedGuard.isNegated()) {
visitDeoptBegin(
AbstractBeginNode.prevBegin(mergePredecessor),
fixedGuard.getAction(),
fixedGuard.getReason(),
fixedGuard.getSpeculation(),
fixedGuard.graph());
}
}
}
@Override
protected void run(final StructuredGraph graph, PhaseContext context) {
assert graph.hasValueProxies() : "ConvertDeoptimizeToGuardPhase always creates proxies";
if (graph.getNodes(DeoptimizeNode.TYPE).isEmpty()) {
return;
}
for (DeoptimizeNode d : graph.getNodes(DeoptimizeNode.TYPE)) {
assert d.isAlive();
visitDeoptBegin(
AbstractBeginNode.prevBegin(d), d.action(), d.reason(), d.getSpeculation(), graph);
}
if (context != null) {
for (FixedGuardNode fixedGuard : graph.getNodes(FixedGuardNode.TYPE)) {
trySplitFixedGuard(fixedGuard, context);
}
}
new DeadCodeEliminationPhase(Optional).apply(graph);
}
private void processFixedGuardAndPhis(
FixedGuardNode fixedGuard,
PhaseContext context,
CompareNode compare,
ValueNode x,
ValuePhiNode xPhi,
ValueNode y,
ValuePhiNode yPhi) {
AbstractBeginNode pred = AbstractBeginNode.prevBegin(fixedGuard);
if (pred instanceof AbstractMergeNode) {
AbstractMergeNode merge = (AbstractMergeNode) pred;
if (xPhi != null && xPhi.merge() != merge) {
return;
}
if (yPhi != null && yPhi.merge() != merge) {
return;
}
processFixedGuardAndMerge(fixedGuard, context, compare, x, xPhi, y, yPhi, merge);
}
}
private void visitDeoptBegin(
AbstractBeginNode deoptBegin,
DeoptimizationAction deoptAction,
DeoptimizationReason deoptReason,
JavaConstant speculation,
StructuredGraph graph) {
if (deoptBegin.predecessor() instanceof AbstractBeginNode) {
/* Walk up chains of LoopExitNodes to the "real" BeginNode that leads to deoptimization. */
visitDeoptBegin(
(AbstractBeginNode) deoptBegin.predecessor(),
deoptAction,
deoptReason,
speculation,
graph);
return;
}
if (deoptBegin instanceof AbstractMergeNode) {
AbstractMergeNode mergeNode = (AbstractMergeNode) deoptBegin;
Debug.log("Visiting %s", mergeNode);
FixedNode next = mergeNode.next();
while (mergeNode.isAlive()) {
AbstractEndNode end = mergeNode.forwardEnds().first();
AbstractBeginNode newBeginNode = findBeginNode(end);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
}
assert next.isAlive();
AbstractBeginNode newBeginNode = findBeginNode(next);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
return;
} else if (deoptBegin.predecessor() instanceof IfNode) {
IfNode ifNode = (IfNode) deoptBegin.predecessor();
AbstractBeginNode otherBegin = ifNode.trueSuccessor();
LogicNode conditionNode = ifNode.condition();
FixedGuardNode guard =
graph.add(
new FixedGuardNode(
conditionNode,
deoptReason,
deoptAction,
speculation,
deoptBegin == ifNode.trueSuccessor()));
FixedWithNextNode pred = (FixedWithNextNode) ifNode.predecessor();
AbstractBeginNode survivingSuccessor;
if (deoptBegin == ifNode.trueSuccessor()) {
survivingSuccessor = ifNode.falseSuccessor();
} else {
survivingSuccessor = ifNode.trueSuccessor();
}
graph.removeSplitPropagate(ifNode, survivingSuccessor);
Node newGuard = guard;
if (survivingSuccessor instanceof LoopExitNode) {
newGuard = ProxyNode.forGuard(guard, (LoopExitNode) survivingSuccessor, graph);
}
survivingSuccessor.replaceAtUsages(InputType.Guard, newGuard);
Debug.log(
"Converting deopt on %-5s branch of %s to guard for remaining branch %s.",
deoptBegin == ifNode.trueSuccessor() ? "true" : "false", ifNode, otherBegin);
FixedNode next = pred.next();
pred.setNext(guard);
guard.setNext(next);
survivingSuccessor.simplify(simplifierTool);
return;
}
// We could not convert the control split - at least cut off control flow after the split.
FixedWithNextNode deoptPred = deoptBegin;
FixedNode next = deoptPred.next();
if (!(next instanceof DeoptimizeNode)) {
DeoptimizeNode newDeoptNode =
graph.add(new DeoptimizeNode(deoptAction, deoptReason, speculation));
deoptPred.setNext(newDeoptNode);
assert deoptPred == newDeoptNode.predecessor();
GraphUtil.killCFG(next);
}
}
@Test
public void testImplies() {
StructuredGraph graph = new StructuredGraph(AllowAssumptions.YES);
EndNode trueEnd = graph.add(new EndNode());
EndNode falseEnd = graph.add(new EndNode());
AbstractBeginNode trueBegin = graph.add(new BeginNode());
trueBegin.setNext(trueEnd);
AbstractBeginNode falseBegin = graph.add(new BeginNode());
falseBegin.setNext(falseEnd);
IfNode ifNode = graph.add(new IfNode(null, trueBegin, falseBegin, 0.5));
graph.start().setNext(ifNode);
AbstractMergeNode merge = graph.add(new MergeNode());
merge.addForwardEnd(trueEnd);
merge.addForwardEnd(falseEnd);
ReturnNode returnNode = graph.add(new ReturnNode(null));
merge.setNext(returnNode);
dumpGraph(graph);
ControlFlowGraph cfg = ControlFlowGraph.compute(graph, true, true, true, true);
List<Block> blocks = cfg.getBlocks();
// check number of blocks
assertDeepEquals(4, blocks.size());
// check block - node assignment
assertDeepEquals(blocks.get(0), cfg.blockFor(graph.start()));
assertDeepEquals(blocks.get(0), cfg.blockFor(ifNode));
assertDeepEquals(blocks.get(1), cfg.blockFor(trueBegin));
assertDeepEquals(blocks.get(1), cfg.blockFor(trueEnd));
assertDeepEquals(blocks.get(2), cfg.blockFor(falseBegin));
assertDeepEquals(blocks.get(2), cfg.blockFor(falseEnd));
assertDeepEquals(blocks.get(3), cfg.blockFor(merge));
assertDeepEquals(blocks.get(3), cfg.blockFor(returnNode));
// check postOrder
Iterator<Block> it = cfg.postOrder().iterator();
for (int i = blocks.size() - 1; i >= 0; i--) {
assertTrue(it.hasNext());
Block b = it.next();
assertDeepEquals(blocks.get(i), b);
}
// check dominators
assertDominator(blocks.get(0), null);
assertDominator(blocks.get(1), blocks.get(0));
assertDominator(blocks.get(2), blocks.get(0));
assertDominator(blocks.get(3), blocks.get(0));
// check dominated
assertDominatedSize(blocks.get(0), 3);
assertDominatedSize(blocks.get(1), 0);
assertDominatedSize(blocks.get(2), 0);
assertDominatedSize(blocks.get(3), 0);
// check postdominators
assertPostdominator(blocks.get(0), blocks.get(3));
assertPostdominator(blocks.get(1), blocks.get(3));
assertPostdominator(blocks.get(2), blocks.get(3));
assertPostdominator(blocks.get(3), null);
}
@SuppressWarnings("try")
private AnchoringNode process(
final Block b, final NodeBitMap activeGuards, final AnchoringNode startAnchor) {
final LoweringToolImpl loweringTool =
new LoweringToolImpl(context, startAnchor, activeGuards, b.getBeginNode());
// Lower the instructions of this block.
List<Node> nodes = schedule.nodesFor(b);
for (Node node : nodes) {
if (node.isDeleted()) {
// This case can happen when previous lowerings deleted nodes.
continue;
}
// Cache the next node to be able to reconstruct the previous of the next node
// after lowering.
FixedNode nextNode = null;
if (node instanceof FixedWithNextNode) {
nextNode = ((FixedWithNextNode) node).next();
} else {
nextNode = loweringTool.lastFixedNode().next();
}
if (node instanceof Lowerable) {
Collection<Node> unscheduledUsages = null;
assert (unscheduledUsages = getUnscheduledUsages(node)) != null;
Mark preLoweringMark = node.graph().getMark();
try (DebugCloseable s = node.graph().withNodeContext(node)) {
((Lowerable) node).lower(loweringTool);
}
if (loweringTool.guardAnchor.asNode().isDeleted()) {
// TODO nextNode could be deleted but this is not currently supported
assert nextNode.isAlive();
loweringTool.guardAnchor = AbstractBeginNode.prevBegin(nextNode);
}
assert checkPostNodeLowering(node, loweringTool, preLoweringMark, unscheduledUsages);
}
if (!nextNode.isAlive()) {
// can happen when the rest of the block is killed by lowering
// (e.g. by an unconditional deopt)
break;
} else {
Node nextLastFixed = nextNode.predecessor();
if (!(nextLastFixed instanceof FixedWithNextNode)) {
// insert begin node, to have a valid last fixed for next lowerable node.
// This is about lowering a FixedWithNextNode to a control split while this
// FixedWithNextNode is followed by some kind of BeginNode.
// For example the when a FixedGuard followed by a loop exit is lowered to a
// control-split + deopt.
AbstractBeginNode begin = node.graph().add(new BeginNode());
nextLastFixed.replaceFirstSuccessor(nextNode, begin);
begin.setNext(nextNode);
nextLastFixed = begin;
}
loweringTool.setLastFixedNode((FixedWithNextNode) nextLastFixed);
}
}
return loweringTool.getCurrentGuardAnchor();
}