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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package org.graalvm.compiler.phases.common;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.graalvm.compiler.core.common.cfg.Loop;
import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.debug.DebugCloseable;
import org.graalvm.compiler.nodes.AbstractDeoptimizeNode;
import org.graalvm.compiler.nodes.AbstractMergeNode;
import org.graalvm.compiler.nodes.DynamicDeoptimizeNode;
import org.graalvm.compiler.nodes.EndNode;
import org.graalvm.compiler.nodes.FrameState;
import org.graalvm.compiler.nodes.LoopBeginNode;
import org.graalvm.compiler.nodes.LoopExitNode;
import org.graalvm.compiler.nodes.MergeNode;
import org.graalvm.compiler.nodes.PhiNode;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.ValuePhiNode;
import org.graalvm.compiler.nodes.cfg.Block;
import org.graalvm.compiler.nodes.cfg.ControlFlowGraph;
import org.graalvm.compiler.phases.BasePhase;
import org.graalvm.compiler.phases.tiers.MidTierContext;

This phase tries to find DeoptimizeNodes which use the same FrameState and merges them together.
/** * This phase tries to find {@link AbstractDeoptimizeNode DeoptimizeNodes} which use the same * {@link FrameState} and merges them together. */
public class DeoptimizationGroupingPhase extends BasePhase<MidTierContext> { @Override @SuppressWarnings("try") protected void run(StructuredGraph graph, MidTierContext context) { ControlFlowGraph cfg = null; for (FrameState fs : graph.getNodes(FrameState.TYPE)) { Iterator<AbstractDeoptimizeNode> iterator = fs.usages().filter(AbstractDeoptimizeNode.class).iterator(); if (!iterator.hasNext()) { // No deopt continue; } AbstractDeoptimizeNode first = iterator.next(); if (!iterator.hasNext()) { // Only 1 deopt continue; } // There is more than one deopt, create a merge if (cfg == null) { cfg = ControlFlowGraph.compute(graph, true, true, false, false); } AbstractMergeNode merge = graph.add(new MergeNode()); EndNode firstEnd = graph.add(new EndNode()); ValueNode actionAndReason = first.getActionAndReason(context.getMetaAccess()); ValueNode speculation = first.getSpeculation(context.getMetaAccess()); PhiNode reasonActionPhi = graph.addWithoutUnique(new ValuePhiNode(StampFactory.forKind(actionAndReason.getStackKind()), merge)); PhiNode speculationPhi = graph.addWithoutUnique(new ValuePhiNode(StampFactory.forKind(speculation.getStackKind()), merge)); merge.addForwardEnd(firstEnd); reasonActionPhi.addInput(actionAndReason); speculationPhi.addInput(speculation); first.replaceAtPredecessor(firstEnd); exitLoops(first, firstEnd, cfg); DynamicDeoptimizeNode dynamicDeopt; try (DebugCloseable position = first.withNodeSourcePosition()) { dynamicDeopt = new DynamicDeoptimizeNode(reasonActionPhi, speculationPhi); merge.setNext(graph.add(dynamicDeopt)); } List<AbstractDeoptimizeNode> obsoletes = new LinkedList<>(); obsoletes.add(first); do { AbstractDeoptimizeNode deopt = iterator.next(); EndNode newEnd = graph.add(new EndNode()); merge.addForwardEnd(newEnd); reasonActionPhi.addInput(deopt.getActionAndReason(context.getMetaAccess())); speculationPhi.addInput(deopt.getSpeculation(context.getMetaAccess())); deopt.replaceAtPredecessor(newEnd); exitLoops(deopt, newEnd, cfg); obsoletes.add(deopt); } while (iterator.hasNext()); dynamicDeopt.setStateBefore(fs); for (AbstractDeoptimizeNode obsolete : obsoletes) { obsolete.safeDelete(); } } } private static void exitLoops(AbstractDeoptimizeNode deopt, EndNode end, ControlFlowGraph cfg) { Block block = cfg.blockFor(deopt); Loop<Block> loop = block.getLoop(); while (loop != null) { end.graph().addBeforeFixed(end, end.graph().add(new LoopExitNode((LoopBeginNode) loop.getHeader().getBeginNode()))); loop = loop.getParent(); } } @Override public float codeSizeIncrease() { return 2.5f; } }