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package org.graalvm.compiler.nodes.extended;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_UNKNOWN;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_UNKNOWN;

import java.util.Arrays;

import org.graalvm.compiler.core.common.type.AbstractPointerStamp;
import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.NodeSuccessorList;
import org.graalvm.compiler.graph.spi.SimplifierTool;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.AbstractBeginNode;
import org.graalvm.compiler.nodes.ControlSplitNode;
import org.graalvm.compiler.nodes.ValueNode;

import jdk.vm.ci.meta.Constant;

The SwitchNode class is the base of both lookup and table switches.
/** * The {@code SwitchNode} class is the base of both lookup and table switches. */
// @formatter:off @NodeInfo(cycles = CYCLES_UNKNOWN, cyclesRationale = "We cannot estimate the runtime cost of a switch statement without knowing the number" + "of case statements and the involved keys.", size = SIZE_UNKNOWN, sizeRationale = "We cannot estimate the code size of a switch statement without knowing the number" + "of case statements.") // @formatter:on public abstract class SwitchNode extends ControlSplitNode { public static final NodeClass<SwitchNode> TYPE = NodeClass.create(SwitchNode.class); @Successor protected NodeSuccessorList<AbstractBeginNode> successors; @Input protected ValueNode value; // do not change the contents of these arrays: protected final double[] keyProbabilities; protected final int[] keySuccessors;
Constructs a new Switch.
Params:
  • value – the instruction that provides the value to be switched over
  • successors – the list of successors of this switch
/** * Constructs a new Switch. * * @param value the instruction that provides the value to be switched over * @param successors the list of successors of this switch */
protected SwitchNode(NodeClass<? extends SwitchNode> c, ValueNode value, AbstractBeginNode[] successors, int[] keySuccessors, double[] keyProbabilities) { super(c, StampFactory.forVoid()); assert value.stamp().getStackKind().isNumericInteger() || value.stamp() instanceof AbstractPointerStamp : value.stamp() + " key not supported by SwitchNode"; assert keySuccessors.length == keyProbabilities.length; this.successors = new NodeSuccessorList<>(this, successors); this.value = value; this.keySuccessors = keySuccessors; this.keyProbabilities = keyProbabilities; assert assertProbabilities(); } private boolean assertProbabilities() { double total = 0; for (double d : keyProbabilities) { total += d; assert d >= 0.0 : "Cannot have negative probabilities in switch node: " + d; } assert total > 0.999 && total < 1.001 : "Total " + total; return true; } @Override public double probability(AbstractBeginNode successor) { double sum = 0; for (int i = 0; i < keySuccessors.length; i++) { if (successors.get(keySuccessors[i]) == successor) { sum += keyProbabilities[i]; } } return sum; } public ValueNode value() { return value; } public abstract boolean isSorted();
The number of distinct keys in this switch.
/** * The number of distinct keys in this switch. */
public abstract int keyCount();
The key at the specified position, encoded in a Constant.
/** * The key at the specified position, encoded in a Constant. */
public abstract Constant keyAt(int i); public boolean structureEquals(SwitchNode switchNode) { return Arrays.equals(keySuccessors, switchNode.keySuccessors) && equalKeys(switchNode); }
Returns true if the switch has the same keys in the same order as this switch.
/** * Returns true if the switch has the same keys in the same order as this switch. */
public abstract boolean equalKeys(SwitchNode switchNode);
Returns the index of the successor belonging to the key at the specified index.
/** * Returns the index of the successor belonging to the key at the specified index. */
public int keySuccessorIndex(int i) { return keySuccessors[i]; }
Returns the successor for the key at the given index.
/** * Returns the successor for the key at the given index. */
public AbstractBeginNode keySuccessor(int i) { return successors.get(keySuccessors[i]); }
Returns the probability of the key at the given index.
/** * Returns the probability of the key at the given index. */
public double keyProbability(int i) { return keyProbabilities[i]; }
Returns the index of the default (fall through) successor of this switch.
/** * Returns the index of the default (fall through) successor of this switch. */
public int defaultSuccessorIndex() { return keySuccessors[keySuccessors.length - 1]; } public AbstractBeginNode blockSuccessor(int i) { return successors.get(i); } public void setBlockSuccessor(int i, AbstractBeginNode s) { successors.set(i, s); } public int blockSuccessorCount() { return successors.count(); }
Gets the successor corresponding to the default (fall through) case.
Returns:the default successor
/** * Gets the successor corresponding to the default (fall through) case. * * @return the default successor */
public AbstractBeginNode defaultSuccessor() { if (defaultSuccessorIndex() == -1) { throw new GraalError("unexpected"); } return successors.get(defaultSuccessorIndex()); } @Override public AbstractBeginNode getPrimarySuccessor() { return this.defaultSuccessor(); }
Delete all other successors except for the one reached by survivingEdge.
Params:
  • tool –
  • survivingEdge – index of the edge in the successors list
/** * Delete all other successors except for the one reached by {@code survivingEdge}. * * @param tool * @param survivingEdge index of the edge in the {@link SwitchNode#successors} list */
protected void killOtherSuccessors(SimplifierTool tool, int survivingEdge) { for (Node successor : successors()) { /* * Deleting a branch change change the successors so reload the surviving successor each * time. */ if (successor != blockSuccessor(survivingEdge)) { tool.deleteBranch(successor); } } tool.addToWorkList(blockSuccessor(survivingEdge)); graph().removeSplit(this, blockSuccessor(survivingEdge)); } }