public class DeadCodeEliminationPhase extends Phase {
public static class Options {
// @formatter:off
@Option(help = "Disable optional dead code eliminations", type = OptionType.Debug)
public static final OptionValue<Boolean> ReduceDCE = new OptionValue<>(true);
// @formatter:on
}
// Metrics
private static final DebugMetric metricNodesRemoved = Debug.metric("NodesRemoved");
public enum Optionality {
Optional,
Required;
}
/**
* Creates a dead code elimination phase that will be run irrespective of {@link
* Options#ReduceDCE}.
*/
public DeadCodeEliminationPhase() {
this(Optionality.Required);
}
/**
* Creates a dead code elimination phase that will be run only if it is {@linkplain
* Optionality#Required non-optional} or {@link Options#ReduceDCE} is false.
*/
public DeadCodeEliminationPhase(Optionality optionality) {
this.optional = optionality == Optionality.Optional;
}
private final boolean optional;
@Override
public void run(StructuredGraph graph) {
if (optional && Options.ReduceDCE.getValue()) {
return;
}
NodeFlood flood = graph.createNodeFlood();
int totalNodeCount = graph.getNodeCount();
flood.add(graph.start());
iterateSuccessorsAndInputs(flood);
int totalMarkedCount = flood.getTotalMarkedCount();
if (totalNodeCount == totalMarkedCount) {
// All nodes are live => nothing more to do.
return;
} else {
// Some nodes are not marked alive and therefore dead => proceed.
assert totalNodeCount > totalMarkedCount;
}
deleteNodes(flood, graph);
}
private static void iterateSuccessorsAndInputs(NodeFlood flood) {
BiConsumer<Node, Node> consumer =
(n, succOrInput) -> {
assert succOrInput.isAlive() : "dead successor or input " + succOrInput + " in " + n;
flood.add(succOrInput);
};
for (Node current : flood) {
if (current instanceof AbstractEndNode) {
AbstractEndNode end = (AbstractEndNode) current;
flood.add(end.merge());
} else {
current.acceptSuccessors(consumer);
current.acceptInputs(consumer);
}
}
}
private static void deleteNodes(NodeFlood flood, StructuredGraph graph) {
BiConsumer<Node, Node> consumer =
(n, input) -> {
if (input.isAlive() && flood.isMarked(input)) {
input.removeUsage(n);
}
};
for (Node node : graph.getNodes()) {
if (!flood.isMarked(node)) {
node.markDeleted();
node.acceptInputs(consumer);
metricNodesRemoved.increment();
}
}
}
}
public class GreedyInliningPolicy extends AbstractInliningPolicy {
private static final DebugMetric metricInliningStoppedByMaxDesiredSize =
Debug.metric("InliningStoppedByMaxDesiredSize");
public GreedyInliningPolicy(Map<Invoke, Double> hints) {
super(hints);
}
public boolean continueInlining(StructuredGraph currentGraph) {
if (currentGraph.getNodeCount() >= MaximumDesiredSize.getValue()) {
InliningUtil.logInliningDecision("inlining is cut off by MaximumDesiredSize");
metricInliningStoppedByMaxDesiredSize.increment();
return false;
}
return true;
}
@Override
public boolean isWorthInlining(
Replacements replacements,
MethodInvocation invocation,
int inliningDepth,
boolean fullyProcessed) {
final InlineInfo info = invocation.callee();
final double probability = invocation.probability();
final double relevance = invocation.relevance();
if (InlineEverything.getValue()) {
InliningUtil.logInlinedMethod(info, inliningDepth, fullyProcessed, "inline everything");
return true;
}
if (isIntrinsic(replacements, info)) {
InliningUtil.logInlinedMethod(info, inliningDepth, fullyProcessed, "intrinsic");
return true;
}
if (info.shouldInline()) {
InliningUtil.logInlinedMethod(info, inliningDepth, fullyProcessed, "forced inlining");
return true;
}
double inliningBonus = getInliningBonus(info);
int nodes = info.determineNodeCount();
int lowLevelGraphSize = previousLowLevelGraphSize(info);
if (SmallCompiledLowLevelGraphSize.getValue() > 0
&& lowLevelGraphSize > SmallCompiledLowLevelGraphSize.getValue() * inliningBonus) {
InliningUtil.logNotInlinedMethod(
info,
inliningDepth,
"too large previous low-level graph (low-level-nodes: %d, relevance=%f, probability=%f, bonus=%f, nodes=%d)",
lowLevelGraphSize,
relevance,
probability,
inliningBonus,
nodes);
return false;
}
if (nodes < TrivialInliningSize.getValue() * inliningBonus) {
InliningUtil.logInlinedMethod(
info,
inliningDepth,
fullyProcessed,
"trivial (relevance=%f, probability=%f, bonus=%f, nodes=%d)",
relevance,
probability,
inliningBonus,
nodes);
return true;
}
/*
* TODO (chaeubl): invoked methods that are on important paths but not yet compiled -> will
* be compiled anyways and it is likely that we are the only caller... might be useful to
* inline those methods but increases bootstrap time (maybe those methods are also getting
* queued in the compilation queue concurrently)
*/
double invokes = determineInvokeProbability(info);
if (LimitInlinedInvokes.getValue() > 0
&& fullyProcessed
&& invokes > LimitInlinedInvokes.getValue() * inliningBonus) {
InliningUtil.logNotInlinedMethod(
info,
inliningDepth,
"callee invoke probability is too high (invokeP=%f, relevance=%f, probability=%f, bonus=%f, nodes=%d)",
invokes,
relevance,
probability,
inliningBonus,
nodes);
return false;
}
double maximumNodes =
computeMaximumSize(relevance, (int) (MaximumInliningSize.getValue() * inliningBonus));
if (nodes <= maximumNodes) {
InliningUtil.logInlinedMethod(
info,
inliningDepth,
fullyProcessed,
"relevance-based (relevance=%f, probability=%f, bonus=%f, nodes=%d <= %f)",
relevance,
probability,
inliningBonus,
nodes,
maximumNodes);
return true;
}
InliningUtil.logNotInlinedMethod(
info,
inliningDepth,
"relevance-based (relevance=%f, probability=%f, bonus=%f, nodes=%d > %f)",
relevance,
probability,
inliningBonus,
nodes,
maximumNodes);
return false;
}
}
