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package org.graalvm.compiler.core.test.inlining;

import static org.graalvm.compiler.phases.common.DeadCodeEliminationPhase.Optionality.Optional;

import org.graalvm.compiler.core.test.GraalCompilerTest;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.TTY;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.nodes.Invoke;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;

import org.graalvm.compiler.nodes.java.MethodCallTargetNode;

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.compiler.phases.BasePhase;

import org.graalvm.compiler.phases.OptimisticOptimizations;

import org.graalvm.compiler.phases.PhaseSuite;

import org.graalvm.compiler.phases.common.CanonicalizerPhase;

import org.graalvm.compiler.phases.common.DeadCodeEliminationPhase;

import org.graalvm.compiler.phases.common.inlining.InliningUtil;

import org.graalvm.compiler.phases.tiers.HighTierContext;

import org.graalvm.compiler.phases.tiers.PhaseContext;

import org.graalvm.compiler.virtual.phases.ea.EarlyReadEliminationPhase;

import org.graalvm.compiler.virtual.phases.ea.PartialEscapePhase;

import org.junit.Test;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import sun.misc.Unsafe;

public class NestedLoopEffectsPhaseComplexityTest extends GraalCompilerTest {

    public static int IntSideEffect;

    public static int[] Memory = new int[]{0};

    public static void recursiveLoopMethodUnsafeLoad(int a) {

        if (UNSAFE.getInt(Memory, (long) Unsafe.ARRAY_INT_BASE_OFFSET) == 0) {

            return;

        }

        for (int i = 0; i < a; i++) {

            recursiveLoopMethodUnsafeLoad(i);

        }

    }

    public static void recursiveLoopMethodFieldLoad(int a) {

        if (IntSideEffect == 0) {

            return;

        }

        for (int i = 0; i < a; i++) {

            recursiveLoopMethodFieldLoad(i);

        }

    }

    public static void recursiveLoopMethod(int a) {

        if (a == 0) {

            return;

        }

        for (int i = 0; i < a; i++) {

            recursiveLoopMethod(i);

        }

    }

    private static final boolean LOG_PHASE_TIMINGS = false;

    private static int InliningCountLowerBound = 1;

    private static int InliningCountUpperBound = 32;

    @Test(timeout = 120_000)

    public void inlineDirectRecursiveLoopCallUnsafeLoad() {

        testAndTime("recursiveLoopMethodUnsafeLoad");

    }

    @Test(timeout = 120_000)

    public void inlineDirectRecursiveLoopCallFieldLoad() {

        testAndTime("recursiveLoopMethodFieldLoad");

    }

    @Test(timeout = 120_000)

    public void inlineDirectRecursiveLoopCallNoReads() {

        testAndTime("recursiveLoopMethod");

    }

    private void testAndTime(String snippet) {

        for (int i = InliningCountLowerBound; i < InliningCountUpperBound; i++) {

            StructuredGraph g1 = prepareGraph(snippet, i);

            StructuredGraph g2 = (StructuredGraph) g1.copy(g1.getDebug());

            ResolvedJavaMethod method = g1.method();

            long elapsedRE = runAndTimePhase(g1, new EarlyReadEliminationPhase(new CanonicalizerPhase()));

            long elapsedPEA = runAndTimePhase(g2, new PartialEscapePhase(true, new CanonicalizerPhase(), g1.getOptions()));

            if (LOG_PHASE_TIMINGS) {

                TTY.printf("Needed %dms to run early partial escape analysis on a graph with %d nested loops compiling method %s\n", elapsedPEA, i, method);

            }

            if (LOG_PHASE_TIMINGS) {

                TTY.printf("Needed %dms to run early read elimination on a graph with %d nested loops compiling method %s\n", elapsedRE, i, method);

            }

        }

    }

    private long runAndTimePhase(StructuredGraph g, BasePhase<? super PhaseContext> phase) {

        HighTierContext context = getDefaultHighTierContext();

        long start = System.currentTimeMillis();

        phase.apply(g, context);

        long end = System.currentTimeMillis();

        DebugContext debug = g.getDebug();

        debug.dump(DebugContext.DETAILED_LEVEL, g, "After %s", phase.contractorName());

        return end - start;

    }

    private StructuredGraph prepareGraph(String snippet, int inliningCount) {

        ResolvedJavaMethod callerMethod = getResolvedJavaMethod(snippet);

        StructuredGraph callerGraph = parseEager(callerMethod, AllowAssumptions.YES);

        PhaseSuite<HighTierContext> graphBuilderSuite = getDefaultGraphBuilderSuite();

        HighTierContext context = new HighTierContext(getProviders(), graphBuilderSuite, OptimisticOptimizations.ALL);

        CanonicalizerPhase canonicalizer = new CanonicalizerPhase();

        Invoke next = callerGraph.getNodes(MethodCallTargetNode.TYPE).first().invoke();

        StructuredGraph calleeGraph = parseBytecodes(next.callTarget().targetMethod(), context, canonicalizer);

        ResolvedJavaMethod calleeMethod = next.callTarget().targetMethod();

        for (int i = 0; i < inliningCount; i++) {

            next = callerGraph.getNodes(MethodCallTargetNode.TYPE).first().invoke();

            EconomicSet<Node> canonicalizeNodes = InliningUtil.inlineForCanonicalization(next, calleeGraph, false, calleeMethod);

            canonicalizer.applyIncremental(callerGraph, context, canonicalizeNodes);

            callerGraph.getDebug().dump(DebugContext.DETAILED_LEVEL, callerGraph, "After inlining %s into %s iteration %d", calleeMethod, callerMethod, i);

        }

        return callerGraph;

    }

    private StructuredGraph parseBytecodes(ResolvedJavaMethod method, HighTierContext context, CanonicalizerPhase canonicalizer) {

        OptionValues options = getInitialOptions();

        StructuredGraph newGraph = new StructuredGraph.Builder(options, getDebugContext(options, null, method), AllowAssumptions.NO).method(method).build();

        context.getGraphBuilderSuite().apply(newGraph, context);

        new DeadCodeEliminationPhase(Optional).apply(newGraph);

        canonicalizer.apply(newGraph, context);

        return newGraph;

    }

}