/*
 * Copyright (c) 2011, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * 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).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.graalvm.compiler.nodes;

import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE;

import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumSet;
import java.util.Iterator;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Consumer;
import java.util.stream.Collectors;

import org.graalvm.collections.EconomicMap;
import org.graalvm.collections.EconomicSet;
import org.graalvm.collections.Equivalence;
import org.graalvm.collections.UnmodifiableEconomicMap;
import org.graalvm.compiler.api.replacements.MethodSubstitution;
import org.graalvm.compiler.api.replacements.Snippet;
import org.graalvm.compiler.core.common.CancellationBailoutException;
import org.graalvm.compiler.core.common.CompilationIdentifier;
import org.graalvm.compiler.core.common.GraalOptions;
import org.graalvm.compiler.core.common.cfg.BlockMap;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.debug.DebugContext;
import org.graalvm.compiler.debug.JavaMethodContext;
import org.graalvm.compiler.debug.TTY;
import org.graalvm.compiler.graph.Graph;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeMap;
import org.graalvm.compiler.graph.NodeSourcePosition;
import org.graalvm.compiler.nodes.calc.FloatingNode;
import org.graalvm.compiler.nodes.cfg.Block;
import org.graalvm.compiler.nodes.cfg.ControlFlowGraph;
import org.graalvm.compiler.nodes.java.ExceptionObjectNode;
import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
import org.graalvm.compiler.nodes.spi.VirtualizableAllocation;
import org.graalvm.compiler.nodes.util.GraphUtil;
import org.graalvm.compiler.options.OptionValues;

import jdk.vm.ci.code.BytecodeFrame;
import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.Assumptions.Assumption;
import jdk.vm.ci.meta.DefaultProfilingInfo;
import jdk.vm.ci.meta.JavaMethod;
import jdk.vm.ci.meta.ProfilingInfo;
import jdk.vm.ci.meta.ResolvedJavaField;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.SpeculationLog;
import jdk.vm.ci.meta.TriState;
import jdk.vm.ci.runtime.JVMCICompiler;

A graph that contains at least one distinguished node : the start node. This node is the start of the control flow of the graph. /**
 * A graph that contains at least one distinguished node : the {@link #start() start} node. This
 * node is the start of the control flow of the graph.
 */
public final class StructuredGraph extends Graph implements JavaMethodContext {

    
The different stages of the compilation of a Graph regarding the status of guards, deoptimizations and 
frame states. The stage of a graph progresses monotonously. /**
     * The different stages of the compilation of a {@link Graph} regarding the status of
     * {@link GuardNode guards}, {@link DeoptimizingNode deoptimizations} and {@link FrameState
     * frame states}. The stage of a graph progresses monotonously.
     */
    public enum GuardsStage {
        
During this stage, there can be floating DeoptimizingNode such as GuardNodes. New DeoptimizingNodes can be introduced without constraints. FrameState nodes are associated with StateSplit nodes. /**
         * During this stage, there can be {@link FloatingNode floating} {@link DeoptimizingNode}
         * such as {@link GuardNode GuardNodes}. New {@link DeoptimizingNode DeoptimizingNodes} can
         * be introduced without constraints. {@link FrameState} nodes are associated with
         * {@link StateSplit} nodes.
         */
        FLOATING_GUARDS,
        
During this stage, all DeoptimizingNodes must be fixed but new DeoptimizingNodes can still be introduced. FrameState nodes are still associated with StateSplit nodes. /**
         * During this stage, all {@link DeoptimizingNode DeoptimizingNodes} must be
         * {@link FixedNode fixed} but new {@link DeoptimizingNode DeoptimizingNodes} can still be
         * introduced. {@link FrameState} nodes are still associated with {@link StateSplit} nodes.
         */
        FIXED_DEOPTS,
        
During this stage, all DeoptimizingNodes must be fixed. New DeoptimizingNodes can not be introduced any more. FrameState nodes are now associated with DeoptimizingNode nodes. /**
         * During this stage, all {@link DeoptimizingNode DeoptimizingNodes} must be
         * {@link FixedNode fixed}. New {@link DeoptimizingNode DeoptimizingNodes} can not be
         * introduced any more. {@link FrameState} nodes are now associated with
         * {@link DeoptimizingNode} nodes.
         */
        AFTER_FSA;

        public boolean allowsFloatingGuards() {
            return this == FLOATING_GUARDS;
        }

        public boolean allowsGuardInsertion() {
            return this.ordinal() <= FIXED_DEOPTS.ordinal();
        }

        public boolean areFrameStatesAtDeopts() {
            return this == AFTER_FSA;
        }

        public boolean areFrameStatesAtSideEffects() {
            return !this.areFrameStatesAtDeopts();
        }

        public boolean areDeoptsFixed() {
            return this.ordinal() >= FIXED_DEOPTS.ordinal();
        }

        public boolean requiresValueProxies() {
            return this != AFTER_FSA;
        }
    }

    
Constants denoting whether or not Assumptions can be made while processing a graph. /**
     * Constants denoting whether or not {@link Assumption}s can be made while processing a graph.
     */
    public enum AllowAssumptions {
        YES,
        NO;

        public static AllowAssumptions ifTrue(boolean flag) {
            return flag ? YES : NO;
        }

        public static AllowAssumptions ifNonNull(Assumptions assumptions) {
            return assumptions != null ? YES : NO;
        }
    }

    
Different stages of the compilation regarding the status of various graph properties.
/**
     * Different stages of the compilation regarding the status of various graph properties.
     */
    public enum StageFlags {
        AFTER_FLOATING_READ_PHASE,
        AFTER_FIXED_READ_PHASE,
        AFTER_VALUE_PROXY_REMOVAL,
        AFTER_EXPAND_LOGIC,
        AFTER_FINAL_CANONICALIZATION
    }

    public static class ScheduleResult {
        private final ControlFlowGraph cfg;
        private final NodeMap<Block> nodeToBlockMap;
        private final BlockMap<List<Node>> blockToNodesMap;

        public ScheduleResult(ControlFlowGraph cfg, NodeMap<Block> nodeToBlockMap, BlockMap<List<Node>> blockToNodesMap) {
            this.cfg = cfg;
            this.nodeToBlockMap = nodeToBlockMap;
            this.blockToNodesMap = blockToNodesMap;
        }

        public ControlFlowGraph getCFG() {
            return cfg;
        }

        public NodeMap<Block> getNodeToBlockMap() {
            return nodeToBlockMap;
        }

        public BlockMap<List<Node>> getBlockToNodesMap() {
            return blockToNodesMap;
        }

        public List<Node> nodesFor(Block block) {
            return blockToNodesMap.get(block);
        }
    }

    
Object used to create a StructuredGraph. /**
     * Object used to create a {@link StructuredGraph}.
     */
    public static class Builder {
        private String name;
        private final Assumptions assumptions;
        private SpeculationLog speculationLog;
        private ResolvedJavaMethod rootMethod;
        private CompilationIdentifier compilationId = CompilationIdentifier.INVALID_COMPILATION_ID;
        private int entryBCI = JVMCICompiler.INVOCATION_ENTRY_BCI;
        private boolean useProfilingInfo = true;
        private boolean recordInlinedMethods = true;
        private boolean trackNodeSourcePosition;
        private final OptionValues options;
        private Cancellable cancellable = null;
        private final DebugContext debug;
        private NodeSourcePosition callerContext;
        private boolean isSubstitution;

        
Creates a builder for a graph.
/**
         * Creates a builder for a graph.
         */
        public Builder(OptionValues options, DebugContext debug, AllowAssumptions allowAssumptions) {
            this.options = options;
            this.debug = debug;
            this.assumptions = allowAssumptions == AllowAssumptions.YES ? new Assumptions() : null;
            this.trackNodeSourcePosition = Graph.trackNodeSourcePositionDefault(options, debug);
        }

        
Creates a builder for a graph that does not support Assumptions. /**
         * Creates a builder for a graph that does not support {@link Assumptions}.
         */
        public Builder(OptionValues options, DebugContext debug) {
            this.options = options;
            this.debug = debug;
            this.assumptions = null;
            this.trackNodeSourcePosition = Graph.trackNodeSourcePositionDefault(options, debug);
        }

        public String getName() {
            return name;
        }

        public Builder name(String s) {
            this.name = s;
            return this;
        }

        
See Also:
isSubstitution.isSubstitution/**
         * @see StructuredGraph#isSubstitution
         */
        public Builder setIsSubstitution(boolean flag) {
            this.isSubstitution = flag;
            return this;
        }

        public ResolvedJavaMethod getMethod() {
            return rootMethod;
        }

        public Builder method(ResolvedJavaMethod method) {
            this.rootMethod = method;
            return this;
        }

        public DebugContext getDebug() {
            return debug;
        }

        public SpeculationLog getSpeculationLog() {
            return speculationLog;
        }

        public Builder speculationLog(SpeculationLog log) {
            this.speculationLog = log;
            return this;
        }

        public CompilationIdentifier getCompilationId() {
            return compilationId;
        }

        public Builder compilationId(CompilationIdentifier id) {
            this.compilationId = id;
            return this;
        }

        public Cancellable getCancellable() {
            return cancellable;
        }

        public Builder cancellable(Cancellable cancel) {
            this.cancellable = cancel;
            return this;
        }

        public int getEntryBCI() {
            return entryBCI;
        }

        public Builder entryBCI(int bci) {
            this.entryBCI = bci;
            return this;
        }

        public boolean getUseProfilingInfo() {
            return useProfilingInfo;
        }

        public Builder useProfilingInfo(boolean flag) {
            this.useProfilingInfo = flag;
            return this;
        }

        public boolean getRecordInlinedMethods() {
            return recordInlinedMethods;
        }

        public Builder recordInlinedMethods(boolean flag) {
            this.recordInlinedMethods = flag;
            return this;
        }

        public Builder trackNodeSourcePosition(boolean flag) {
            if (flag) {
                this.trackNodeSourcePosition = true;
            }
            return this;
        }

        public Builder callerContext(NodeSourcePosition context) {
            this.callerContext = context;
            return this;
        }

        public StructuredGraph build() {
            List<ResolvedJavaMethod> inlinedMethods = recordInlinedMethods ? new ArrayList<>() : null;
            // @formatter:off
            return new StructuredGraph(name,
                            rootMethod,
                            entryBCI,
                            assumptions,
                            speculationLog,
                            useProfilingInfo,
                            isSubstitution,
                            inlinedMethods,
                            trackNodeSourcePosition,
                            compilationId,
                            options,
                            debug,
                            cancellable,
                            callerContext);
            // @formatter:on
        }
    }

    public static final long INVALID_GRAPH_ID = -1;
    private static final AtomicLong uniqueGraphIds = new AtomicLong();

    private StartNode start;
    private ResolvedJavaMethod rootMethod;
    private final long graphId;
    private final CompilationIdentifier compilationId;
    private final int entryBCI;
    private GuardsStage guardsStage = GuardsStage.FLOATING_GUARDS;
    private EnumSet<StageFlags> stageFlags = EnumSet.noneOf(StageFlags.class);
    private FrameStateVerification frameStateVerification;

    
Different node types verified during FrameStateVerification. See FrameStateVerification for details. /**
     * Different node types verified during {@linkplain FrameStateVerification}. See
     * {@linkplain FrameStateVerification} for details.
     */
    public enum FrameStateVerificationFeature {
        STATE_SPLITS,
        MERGES,
        LOOP_BEGINS,
        LOOP_EXITS
    }

    
The different stages of the compilation of a Graph regarding the status of FrameState verification of AbstractStateSplit state after. Verification starts with the mode ALL, i.e., all state splits with side-effects, merges and loop exits need a proper state after. The verification mode progresses monotonously until the NONE mode is reached. From there on, no further AbstractStateSplit.stateAfter verification happens. /**
     * The different stages of the compilation of a {@link Graph} regarding the status of
     * {@linkplain FrameState} verification of {@linkplain AbstractStateSplit} state after.
     * Verification starts with the mode {@linkplain FrameStateVerification#ALL}, i.e., all state
     * splits with side-effects, merges and loop exits need a proper state after. The verification
     * mode progresses monotonously until the {@linkplain FrameStateVerification#NONE} mode is
     * reached. From there on, no further {@linkplain AbstractStateSplit#stateAfter} verification
     * happens.
     */
    public enum FrameStateVerification {
        
Verify all AbstractStateSplit nodes that return true for AbstractStateSplit.hasSideEffect() have a AbstractStateSplit.stateAfter assigned. Additionally, verify LoopExitNode and AbstractMergeNode have a valid AbstractStateSplit.stateAfter. This is necessary to avoid missing FrameState after optimizations. See GraphUtil.mayRemoveSplit for more details. This stage is the initial verification stage for every graph. /**
         * Verify all {@linkplain AbstractStateSplit} nodes that return {@code true} for
         * {@linkplain AbstractStateSplit#hasSideEffect()} have a
         * {@linkplain AbstractStateSplit#stateAfter} assigned. Additionally, verify
         * {@linkplain LoopExitNode} and {@linkplain AbstractMergeNode} have a valid
         * {@linkplain AbstractStateSplit#stateAfter}. This is necessary to avoid missing
         * {@linkplain FrameState} after optimizations. See {@link GraphUtil#mayRemoveSplit} for
         * more details.
         *
         * This stage is the initial verification stage for every graph.
         */
        ALL(EnumSet.allOf(FrameStateVerificationFeature.class)),
        
Same as ALL except that LoopExitNode nodes are no longer verified. /**
         * Same as {@linkplain #ALL} except that {@linkplain LoopExitNode} nodes are no longer
         * verified.
         */
        ALL_EXCEPT_LOOP_EXIT(EnumSet.complementOf(EnumSet.of(FrameStateVerificationFeature.LOOP_EXITS))),
        
Same as ALL_EXCEPT_LOOP_EXIT except that LoopBeginNode are no longer verified. /**
         * Same as {@linkplain #ALL_EXCEPT_LOOP_EXIT} except that {@linkplain LoopBeginNode} are no
         * longer verified.
         */
        ALL_EXCEPT_LOOPS(EnumSet.complementOf(EnumSet.of(FrameStateVerificationFeature.LOOP_BEGINS, FrameStateVerificationFeature.LOOP_EXITS))),
        
Verification is disabled. Typically used after assigning FrameState to DeoptimizeNode or for Snippet compilations. /**
         * Verification is disabled. Typically used after assigning {@linkplain FrameState} to
         * {@linkplain DeoptimizeNode} or for {@linkplain Snippet} compilations.
         */
        NONE(EnumSet.noneOf(FrameStateVerificationFeature.class));

        private EnumSet<FrameStateVerificationFeature> features;

        FrameStateVerification(EnumSet<FrameStateVerificationFeature> features) {
            this.features = features;
        }

        
Determines if the current verification mode implies this feature.
Params:
feature – the other verification feature to check
Returns:
true if this verification mode implies the feature, false otherwise/**
         * Determines if the current verification mode implies this feature.
         *
         * @param feature the other verification feature to check
         * @return {@code true} if this verification mode implies the feature, {@code false}
         *         otherwise
         */
        boolean implies(FrameStateVerificationFeature feature) {
            return this.features.contains(feature);
        }

    }

    private final boolean useProfilingInfo;
    private final Cancellable cancellable;
    private final boolean isSubstitution;

    
The assumptions made while constructing and transforming this graph.
/**
     * The assumptions made while constructing and transforming this graph.
     */
    private final Assumptions assumptions;

    private SpeculationLog speculationLog;

    private ScheduleResult lastSchedule;

    private final InliningLog inliningLog;

    
Call stack (context) leading to construction of this graph.
/**
     * Call stack (context) leading to construction of this graph.
     */
    private final NodeSourcePosition callerContext;

    
Records the methods that were used while constructing this graph, one entry for each time a specific method is used. This will be null if recording of inlined methods is disabled for the graph. /**
     * Records the methods that were used while constructing this graph, one entry for each time a
     * specific method is used. This will be {@code null} if recording of inlined methods is
     * disabled for the graph.
     */
    private final List<ResolvedJavaMethod> methods;

    
Records the fields that were accessed while constructing this graph.
/**
     * Records the fields that were accessed while constructing this graph.
     */
    private EconomicSet<ResolvedJavaField> fields = null;

    private enum UnsafeAccessState {
        NO_ACCESS,
        HAS_ACCESS,
        DISABLED
    }

    private UnsafeAccessState hasUnsafeAccess = UnsafeAccessState.NO_ACCESS;

    public static final boolean USE_PROFILING_INFO = true;

    public static final boolean NO_PROFILING_INFO = false;

    private StructuredGraph(String name,
                    ResolvedJavaMethod method,
                    int entryBCI,
                    Assumptions assumptions,
                    SpeculationLog speculationLog,
                    boolean useProfilingInfo,
                    boolean isSubstitution,
                    List<ResolvedJavaMethod> methods,
                    boolean trackNodeSourcePosition,
                    CompilationIdentifier compilationId,
                    OptionValues options,
                    DebugContext debug,
                    Cancellable cancellable,
                    NodeSourcePosition context) {
        super(name, options, debug, trackNodeSourcePosition);
        this.setStart(add(new StartNode()));
        this.rootMethod = method;
        this.graphId = uniqueGraphIds.incrementAndGet();
        this.compilationId = compilationId;
        this.entryBCI = entryBCI;
        this.assumptions = assumptions;
        this.methods = methods;
        this.speculationLog = speculationLog;
        this.useProfilingInfo = useProfilingInfo;
        this.isSubstitution = isSubstitution;
        assert checkIsSubstitutionInvariants(method, isSubstitution);
        this.cancellable = cancellable;
        this.inliningLog = new InliningLog(rootMethod, GraalOptions.TraceInlining.getValue(options), debug);
        this.callerContext = context;
        this.frameStateVerification = isSubstitution ? FrameStateVerification.NONE : FrameStateVerification.ALL;
    }

    private static boolean checkIsSubstitutionInvariants(ResolvedJavaMethod method, boolean isSubstitution) {
        if (!IS_IN_NATIVE_IMAGE) {
            if (method != null) {
                if (method.getAnnotation(Snippet.class) != null || method.getAnnotation(MethodSubstitution.class) != null) {
                    assert isSubstitution : "Graph for method " + method.format("%H.%n(%p)") +
                                    " annotated by " + Snippet.class.getName() + " or " +
                                    MethodSubstitution.class.getName() +
                                    " must have its `isSubstitution` field set to true";
                }
            }
        }
        return true;
    }

    public void setLastSchedule(ScheduleResult result) {
        lastSchedule = result;
    }

    public ScheduleResult getLastSchedule() {
        return lastSchedule;
    }

    public void clearLastSchedule() {
        setLastSchedule(null);
    }

    @Override
    public boolean maybeCompress() {
        if (super.maybeCompress()) {
            /*
             * The schedule contains a NodeMap which is unusable after compression.
             */
            clearLastSchedule();
            return true;
        }
        return false;
    }

    public Stamp getReturnStamp() {
        Stamp returnStamp = null;
        for (ReturnNode returnNode : getNodes(ReturnNode.TYPE)) {
            ValueNode result = returnNode.result();
            if (result != null) {
                if (returnStamp == null) {
                    returnStamp = result.stamp(NodeView.DEFAULT);
                } else {
                    returnStamp = returnStamp.meet(result.stamp(NodeView.DEFAULT));
                }
            }
        }
        return returnStamp;
    }

    @Override
    public String toString() {
        StringBuilder buf = new StringBuilder(getClass().getSimpleName() + ":" + graphId);
        String sep = "{";
        if (name != null) {
            buf.append(sep);
            buf.append(name);
            sep = ", ";
        }
        if (method() != null) {
            buf.append(sep);
            buf.append(method());
            sep = ", ";
        }

        if (!sep.equals("{")) {
            buf.append("}");
        }
        return buf.toString();
    }

    public StartNode start() {
        return start;
    }

    
Gets the root method from which this graph was built.
Returns:
null if this method was not built from a method or the method is not available/**
     * Gets the root method from which this graph was built.
     *
     * @return null if this method was not built from a method or the method is not available
     */
    public ResolvedJavaMethod method() {
        return rootMethod;
    }

    public int getEntryBCI() {
        return entryBCI;
    }

    public Cancellable getCancellable() {
        return cancellable;
    }

    public void checkCancellation() {
        if (cancellable != null && cancellable.isCancelled()) {
            CancellationBailoutException.cancelCompilation();
        }
    }

    public boolean isOSR() {
        return entryBCI != JVMCICompiler.INVOCATION_ENTRY_BCI;
    }

    public long graphId() {
        return graphId;
    }

    
See Also:
CompilationIdentifier/**
     * @see CompilationIdentifier
     */
    public CompilationIdentifier compilationId() {
        return compilationId;
    }

    public void setStart(StartNode start) {
        this.start = start;
    }

    public InliningLog getInliningLog() {
        return inliningLog;
    }

    public void logInliningTree() {
        if (GraalOptions.TraceInlining.getValue(getOptions())) {
            String formattedTree = getInliningLog().formatAsTree(true);
            if (formattedTree != null) {
                TTY.println(formattedTree);
            }
        }
    }

    
Creates a copy of this graph.
If a node contains an array of objects, only shallow copy of the field is applied.
Params:
newName – the name of the copy, used for debugging purposes (can be null)
duplicationMapCallback – consumer of the duplication map created during the copying
debugForCopy – the debug context for the graph copy. This must not be the debug for this
           graph if this graph can be accessed from multiple threads (e.g., it's in a cache
           accessed by multiple threads)./**
     * Creates a copy of this graph.
     *
     * If a node contains an array of objects, only shallow copy of the field is applied.
     *
     * @param newName the name of the copy, used for debugging purposes (can be null)
     * @param duplicationMapCallback consumer of the duplication map created during the copying
     * @param debugForCopy the debug context for the graph copy. This must not be the debug for this
     *            graph if this graph can be accessed from multiple threads (e.g., it's in a cache
     *            accessed by multiple threads).
     */
    @Override
    protected Graph copy(String newName, Consumer<UnmodifiableEconomicMap<Node, Node>> duplicationMapCallback, DebugContext debugForCopy) {
        return copy(newName, duplicationMapCallback, compilationId, debugForCopy);
    }

    @SuppressWarnings("try")
    private StructuredGraph copy(String newName, Consumer<UnmodifiableEconomicMap<Node, Node>> duplicationMapCallback, CompilationIdentifier newCompilationId, DebugContext debugForCopy) {
        AllowAssumptions allowAssumptions = allowAssumptions();
        StructuredGraph copy = new StructuredGraph(newName,
                        method(),
                        entryBCI,
                        assumptions == null ? null : new Assumptions(),
                        speculationLog,
                        useProfilingInfo,
                        isSubstitution,
                        methods != null ? new ArrayList<>(methods) : null,
                        trackNodeSourcePosition,
                        newCompilationId,
                        getOptions(), debugForCopy, null, callerContext);
        if (allowAssumptions == AllowAssumptions.YES && assumptions != null) {
            copy.assumptions.record(assumptions);
        }
        copy.hasUnsafeAccess = hasUnsafeAccess;
        copy.setGuardsStage(getGuardsStage());
        copy.stageFlags = EnumSet.copyOf(stageFlags);
        copy.trackNodeSourcePosition = trackNodeSourcePosition;
        if (fields != null) {
            copy.fields = createFieldSet(fields);
        }
        EconomicMap<Node, Node> replacements = EconomicMap.create(Equivalence.IDENTITY);
        replacements.put(start, copy.start);
        UnmodifiableEconomicMap<Node, Node> duplicates;
        try (InliningLog.UpdateScope scope = copy.getInliningLog().openDefaultUpdateScope()) {
            duplicates = copy.addDuplicates(getNodes(), this, this.getNodeCount(), replacements);
            if (scope != null) {
                copy.getInliningLog().replaceLog(duplicates, this.getInliningLog());
            }
        }
        if (duplicationMapCallback != null) {
            duplicationMapCallback.accept(duplicates);
        }
        return copy;
    }

    
Params:
debugForCopy – the debug context for the graph copy. This must not be the debug for this
           graph if this graph can be accessed from multiple threads (e.g., it's in a cache
           accessed by multiple threads)./**
     * @param debugForCopy the debug context for the graph copy. This must not be the debug for this
     *            graph if this graph can be accessed from multiple threads (e.g., it's in a cache
     *            accessed by multiple threads).
     */
    public StructuredGraph copyWithIdentifier(CompilationIdentifier newCompilationId, DebugContext debugForCopy) {
        return copy(name, null, newCompilationId, debugForCopy);
    }

    public ParameterNode getParameter(int index) {
        for (ParameterNode param : getNodes(ParameterNode.TYPE)) {
            if (param.index() == index) {
                return param;
            }
        }
        return null;
    }

    public Iterable<Invoke> getInvokes() {
        final Iterator<MethodCallTargetNode> callTargets = getNodes(MethodCallTargetNode.TYPE).iterator();
        return new Iterable<Invoke>() {

            private Invoke next;

            @Override
            public Iterator<Invoke> iterator() {
                return new Iterator<Invoke>() {

                    @Override
                    public boolean hasNext() {
                        if (next == null) {
                            while (callTargets.hasNext()) {
                                Invoke i = callTargets.next().invoke();
                                if (i != null) {
                                    next = i;
                                    return true;
                                }
                            }
                            return false;
                        } else {
                            return true;
                        }
                    }

                    @Override
                    public Invoke next() {
                        try {
                            return next;
                        } finally {
                            next = null;
                        }
                    }

                    @Override
                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

    public boolean hasLoops() {
        return hasNode(LoopBeginNode.TYPE);
    }

    
Unlinks a node from all its control flow neighbors and then removes it from its graph. The node must have no usages. 
Params:
node – the node to be unlinked and removed/**
     * Unlinks a node from all its control flow neighbors and then removes it from its graph. The
     * node must have no {@linkplain Node#usages() usages}.
     *
     * @param node the node to be unlinked and removed
     */
    @SuppressWarnings("static-method")
    public void removeFixed(FixedWithNextNode node) {
        assert node != null;
        if (node instanceof AbstractBeginNode) {
            ((AbstractBeginNode) node).prepareDelete();
        }
        assert node.hasNoUsages() : node + " " + node.getUsageCount() + ", " + node.usages().first();
        GraphUtil.unlinkFixedNode(node);
        node.safeDelete();
    }

    public void replaceFixed(FixedWithNextNode node, Node replacement) {
        if (replacement instanceof FixedWithNextNode) {
            replaceFixedWithFixed(node, (FixedWithNextNode) replacement);
        } else {
            assert replacement != null : "cannot replace " + node + " with null";
            assert replacement instanceof FloatingNode : "cannot replace " + node + " with " + replacement;
            replaceFixedWithFloating(node, (FloatingNode) replacement);
        }
    }

    public void replaceFixedWithFixed(FixedWithNextNode node, FixedWithNextNode replacement) {
        assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
        FixedNode next = node.next();
        node.setNext(null);
        replacement.setNext(next);
        node.replaceAndDelete(replacement);
        if (node == start) {
            setStart((StartNode) replacement);
        }
    }

    @SuppressWarnings("static-method")
    public void replaceFixedWithFloating(FixedWithNextNode node, ValueNode replacement) {
        assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
        GraphUtil.unlinkFixedNode(node);
        node.replaceAtUsagesAndDelete(replacement);
    }

    @SuppressWarnings("static-method")
    public void removeSplit(ControlSplitNode node, AbstractBeginNode survivingSuccessor) {
        assert node != null;
        assert node.hasNoUsages();
        assert survivingSuccessor != null;
        node.clearSuccessors();
        node.replaceAtPredecessor(survivingSuccessor);
        node.safeDelete();
    }

    @SuppressWarnings("static-method")
    public void removeSplitPropagate(ControlSplitNode node, AbstractBeginNode survivingSuccessor) {
        assert node != null;
        assert node.hasNoUsages();
        assert survivingSuccessor != null;
        List<Node> snapshot = node.successors().snapshot();
        node.clearSuccessors();
        node.replaceAtPredecessor(survivingSuccessor);
        node.safeDelete();
        for (Node successor : snapshot) {
            if (successor != null && successor.isAlive()) {
                if (successor != survivingSuccessor) {
                    GraphUtil.killCFG((FixedNode) successor);
                }
            }
        }
    }

    public void replaceSplit(ControlSplitNode node, Node replacement, AbstractBeginNode survivingSuccessor) {
        if (replacement instanceof FixedWithNextNode) {
            replaceSplitWithFixed(node, (FixedWithNextNode) replacement, survivingSuccessor);
        } else {
            assert replacement != null : "cannot replace " + node + " with null";
            assert replacement instanceof FloatingNode : "cannot replace " + node + " with " + replacement;
            replaceSplitWithFloating(node, (FloatingNode) replacement, survivingSuccessor);
        }
    }

    @SuppressWarnings("static-method")
    public void replaceSplitWithFixed(ControlSplitNode node, FixedWithNextNode replacement, AbstractBeginNode survivingSuccessor) {
        assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
        assert survivingSuccessor != null;
        node.clearSuccessors();
        replacement.setNext(survivingSuccessor);
        node.replaceAndDelete(replacement);
    }

    @SuppressWarnings("static-method")
    public void replaceSplitWithFloating(ControlSplitNode node, FloatingNode replacement, AbstractBeginNode survivingSuccessor) {
        assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
        assert survivingSuccessor != null;
        node.clearSuccessors();
        node.replaceAtPredecessor(survivingSuccessor);
        node.replaceAtUsagesAndDelete(replacement);
    }

    @SuppressWarnings("static-method")
    public void replaceWithExceptionSplit(WithExceptionNode node, WithExceptionNode replacement) {
        assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
        node.replaceAtPredecessor(replacement);
        AbstractBeginNode next = node.next();
        AbstractBeginNode exceptionEdge = node.exceptionEdge();
        node.replaceAtUsagesAndDelete(replacement);
        replacement.setNext(next);
        replacement.setExceptionEdge(exceptionEdge);
    }

    @SuppressWarnings("static-method")
    public void addAfterFixed(FixedWithNextNode node, FixedNode newNode) {
        assert node != null && newNode != null && node.isAlive() && newNode.isAlive() : "cannot add " + newNode + " after " + node;
        FixedNode next = node.next();
        node.setNext(newNode);
        if (next != null) {
            assert newNode instanceof FixedWithNextNode;
            FixedWithNextNode newFixedWithNext = (FixedWithNextNode) newNode;
            assert newFixedWithNext.next() == null;
            newFixedWithNext.setNext(next);
        }
    }

    @SuppressWarnings("static-method")
    public void addBeforeFixed(FixedNode node, FixedWithNextNode newNode) {
        assert node != null && newNode != null && node.isAlive() && newNode.isAlive() : "cannot add " + newNode + " before " + node;
        assert node.predecessor() != null && node.predecessor() instanceof FixedWithNextNode : "cannot add " + newNode + " before " + node;
        assert newNode.next() == null : newNode;
        assert !(node instanceof AbstractMergeNode);
        FixedWithNextNode pred = (FixedWithNextNode) node.predecessor();
        pred.setNext(newNode);
        newNode.setNext(node);
    }

    public void reduceDegenerateLoopBegin(LoopBeginNode begin) {
        assert begin.loopEnds().isEmpty() : "Loop begin still has backedges";
        if (begin.forwardEndCount() == 1) { // bypass merge and remove
            reduceTrivialMerge(begin);
        } else { // convert to merge
            AbstractMergeNode merge = this.add(new MergeNode());
            for (EndNode end : begin.forwardEnds()) {
                merge.addForwardEnd(end);
            }
            this.replaceFixedWithFixed(begin, merge);
        }
    }

    @SuppressWarnings("static-method")
    public void reduceTrivialMerge(AbstractMergeNode merge) {
        assert merge.forwardEndCount() == 1;
        assert !(merge instanceof LoopBeginNode) || ((LoopBeginNode) merge).loopEnds().isEmpty();
        for (PhiNode phi : merge.phis().snapshot()) {
            assert phi.valueCount() == 1;
            ValueNode singleValue = phi.valueAt(0);
            if (phi.hasUsages()) {
                phi.replaceAtUsagesAndDelete(singleValue);
            } else {
                phi.safeDelete();
                if (singleValue != null) {
                    GraphUtil.tryKillUnused(singleValue);
                }
            }
        }
        // remove loop exits
        if (merge instanceof LoopBeginNode) {
            ((LoopBeginNode) merge).removeExits();
        }
        AbstractEndNode singleEnd = merge.forwardEndAt(0);
        FixedNode sux = merge.next();
        FrameState stateAfter = merge.stateAfter();
        // evacuateGuards
        merge.prepareDelete((FixedNode) singleEnd.predecessor());
        merge.safeDelete();
        if (stateAfter != null) {
            GraphUtil.tryKillUnused(stateAfter);
        }
        if (sux == null) {
            singleEnd.replaceAtPredecessor(null);
            singleEnd.safeDelete();
        } else {
            singleEnd.replaceAndDelete(sux);
        }
    }

    public GuardsStage getGuardsStage() {
        return guardsStage;
    }

    public void setGuardsStage(GuardsStage guardsStage) {
        assert guardsStage.ordinal() >= this.guardsStage.ordinal();
        this.guardsStage = guardsStage;
    }

    public boolean isAfterFloatingReadPhase() {
        return stageFlags.contains(StageFlags.AFTER_FLOATING_READ_PHASE);
    }

    public boolean isAfterFixedReadPhase() {
        return stageFlags.contains(StageFlags.AFTER_FIXED_READ_PHASE);
    }

    public void setAfterFloatingReadPhase() {
        stageFlags.add(StageFlags.AFTER_FLOATING_READ_PHASE);
    }

    public void setAfterFixReadPhase() {
        stageFlags.add(StageFlags.AFTER_FIXED_READ_PHASE);
    }

    public boolean hasValueProxies() {
        return !stageFlags.contains(StageFlags.AFTER_VALUE_PROXY_REMOVAL);
    }

    public void setAfterValueProxyRemoval() {
        stageFlags.add(StageFlags.AFTER_VALUE_PROXY_REMOVAL);
    }

    public boolean isAfterExpandLogic() {
        return stageFlags.contains(StageFlags.AFTER_EXPAND_LOGIC);
    }

    public void setAfterExpandLogic() {
        stageFlags.add(StageFlags.AFTER_EXPAND_LOGIC);
    }

    public boolean isAfterFinalCanonicalization() {
        return stageFlags.contains(StageFlags.AFTER_FINAL_CANONICALIZATION);
    }

    public void setAfterFinalCanonicalization() {
        stageFlags.add(StageFlags.AFTER_FINAL_CANONICALIZATION);
    }

    
Determines if ProfilingInfo is used during construction of this graph. /**
     * Determines if {@link ProfilingInfo} is used during construction of this graph.
     */
    public boolean useProfilingInfo() {
        return useProfilingInfo;
    }

    
Returns true if this graph is built without parsing the root method or if the root method is annotated by Snippet or MethodSubstitution. This is preferred over querying annotations directly as querying annotations can cause class loading. /**
     * Returns true if this graph is built without parsing the {@linkplain #method() root method} or
     * if the root method is annotated by {@link Snippet} or {@link MethodSubstitution}. This is
     * preferred over querying annotations directly as querying annotations can cause class loading.
     */
    public boolean isSubstitution() {
        return isSubstitution;
    }

    
Gets the profiling info for the root method of this graph. /**
     * Gets the profiling info for the {@linkplain #method() root method} of this graph.
     */
    public ProfilingInfo getProfilingInfo() {
        return getProfilingInfo(method());
    }

    
Gets the profiling info for a given method that is or will be part of this graph, taking into account useProfilingInfo(). /**
     * Gets the profiling info for a given method that is or will be part of this graph, taking into
     * account {@link #useProfilingInfo()}.
     */
    public ProfilingInfo getProfilingInfo(ResolvedJavaMethod m) {
        if (useProfilingInfo && m != null) {
            return m.getProfilingInfo();
        } else {
            return DefaultProfilingInfo.get(TriState.UNKNOWN);
        }
    }

    
Gets the object for recording assumptions while constructing of this graph.
Returns:
null if assumptions cannot be made for this graph/**
     * Gets the object for recording assumptions while constructing of this graph.
     *
     * @return {@code null} if assumptions cannot be made for this graph
     */
    public Assumptions getAssumptions() {
        return assumptions;
    }

    
Returns the AllowAssumptions status for this graph.
Returns:
AllowAssumptions.YES if this graph allows recording assumptions, AllowAssumptions.NO otherwise/**
     * Returns the AllowAssumptions status for this graph.
     *
     * @return {@code AllowAssumptions.YES} if this graph allows recording assumptions,
     *         {@code AllowAssumptions.NO} otherwise
     */
    public AllowAssumptions allowAssumptions() {
        return AllowAssumptions.ifNonNull(assumptions);
    }

    public void recordAssumptions(StructuredGraph inlineGraph) {
        if (this != inlineGraph && getAssumptions() != null) {
            if (inlineGraph.getAssumptions() != null) {
                getAssumptions().record(inlineGraph.getAssumptions());
            }
        } else {
            assert inlineGraph.getAssumptions() == null : String.format("cannot inline graph (%s) which makes assumptions into a graph (%s) that doesn't", inlineGraph, this);
        }
    }

    
Checks that any method referenced from a FrameState is also in the set of methods parsed while building this graph. /**
     * Checks that any method referenced from a {@link FrameState} is also in the set of methods
     * parsed while building this graph.
     */
    private boolean checkFrameStatesAgainstInlinedMethods() {
        for (FrameState fs : getNodes(FrameState.TYPE)) {
            if (!BytecodeFrame.isPlaceholderBci(fs.bci)) {
                ResolvedJavaMethod m = fs.code.getMethod();
                if (!m.equals(rootMethod) && !methods.contains(m)) {
                    SortedSet<String> haystack = new TreeSet<>();
                    if (!methods.contains(rootMethod)) {
                        haystack.add(rootMethod.format("%H.%n(%p)"));
                    }
                    for (ResolvedJavaMethod e : methods) {
                        haystack.add(e.format("%H.%n(%p)"));
                    }
                    throw new AssertionError(String.format("Could not find %s from %s in set(%s)", m.format("%H.%n(%p)"), fs, haystack.stream().collect(Collectors.joining(System.lineSeparator()))));
                }
            }
        }
        return true;
    }

    private static EconomicSet<ResolvedJavaField> createFieldSet(EconomicSet<ResolvedJavaField> init) {
        // Multiple ResolvedJavaField objects can represent the same field so they
        // need to be compared with equals().
        if (init != null) {
            return EconomicSet.create(Equivalence.DEFAULT, init);
        }
        return EconomicSet.create(Equivalence.DEFAULT);
    }

    
Gets an unmodifiable view of the methods that were inlined while constructing this graph.
/**
     * Gets an unmodifiable view of the methods that were inlined while constructing this graph.
     */
    public List<ResolvedJavaMethod> getMethods() {
        if (methods != null) {
            assert isSubstitution || checkFrameStatesAgainstInlinedMethods();
            return Collections.unmodifiableList(methods);
        }
        return Collections.emptyList();
    }

    
Records that method was used to build this graph. /**
     * Records that {@code method} was used to build this graph.
     */
    public void recordMethod(ResolvedJavaMethod method) {
        if (methods != null) {
            methods.add(method);
        }
    }

    
Updates the methods used to build this graph with the methods used to build another graph. /**
     * Updates the {@linkplain #getMethods() methods} used to build this graph with the methods used
     * to build another graph.
     */
    public void updateMethods(StructuredGraph other) {
        if (methods != null) {
            if (other.rootMethod != null) {
                methods.add(other.rootMethod);
            }
            for (ResolvedJavaMethod m : other.methods) {
                methods.add(m);
            }
        }
    }

    
Gets an unmodifiable view of the fields that were accessed while constructing this graph.
Returns:
null if no field accesses were recorded/**
     * Gets an unmodifiable view of the fields that were accessed while constructing this graph.
     *
     * @return {@code null} if no field accesses were recorded
     */
    public EconomicSet<ResolvedJavaField> getFields() {
        return fields;
    }

    
Records that field was accessed in this graph. /**
     * Records that {@code field} was accessed in this graph.
     */
    public void recordField(ResolvedJavaField field) {
        assert GraalOptions.GeneratePIC.getValue(getOptions());
        if (this.fields == null) {
            this.fields = createFieldSet(null);
        }
        fields.add(field);
    }

    
Updates the fields of this graph with the accessed fields of another graph. /**
     * Updates the {@linkplain #getFields() fields} of this graph with the accessed fields of
     * another graph.
     */
    public void updateFields(StructuredGraph other) {
        assert this != other;
        assert GraalOptions.GeneratePIC.getValue(getOptions());
        if (other.fields != null) {
            if (this.fields == null) {
                this.fields = createFieldSet(null);
            }
            this.fields.addAll(other.fields);
        }
    }

    
Gets the input bytecode size from which this graph is constructed. This ignores how many bytecodes in each constituent method are actually parsed (which may be none for methods whose IR is retrieved from a cache or less than the full amount for any given method due to profile guided branch pruning). /**
     * Gets the input bytecode {@linkplain ResolvedJavaMethod#getCodeSize() size} from which this
     * graph is constructed. This ignores how many bytecodes in each constituent method are actually
     * parsed (which may be none for methods whose IR is retrieved from a cache or less than the
     * full amount for any given method due to profile guided branch pruning).
     */
    public int getBytecodeSize() {
        int res = 0;
        if (rootMethod != null) {
            res += rootMethod.getCodeSize();
        }
        if (methods != null) {
            for (ResolvedJavaMethod e : methods) {
                res += e.getCodeSize();
            }
        }
        return res;
    }

    @Override
    public JavaMethod asJavaMethod() {
        return method();
    }

    public boolean hasUnsafeAccess() {
        return hasUnsafeAccess == UnsafeAccessState.HAS_ACCESS;
    }

    public void markUnsafeAccess() {
        if (hasUnsafeAccess == UnsafeAccessState.DISABLED) {
            return;
        }
        hasUnsafeAccess = UnsafeAccessState.HAS_ACCESS;
    }

    public void disableUnsafeAccessTracking() {
        hasUnsafeAccess = UnsafeAccessState.DISABLED;
    }

    public boolean isUnsafeAccessTrackingEnabled() {
        return hasUnsafeAccess != UnsafeAccessState.DISABLED;
    }

    public SpeculationLog getSpeculationLog() {
        return speculationLog;
    }

    public FrameStateVerification getFrameStateVerification() {
        return frameStateVerification;
    }

    public void weakenFrameStateVerification(FrameStateVerification newFrameStateVerification) {
        if (frameStateVerification == FrameStateVerification.NONE) {
            return;
        }
        if (newFrameStateVerification == FrameStateVerification.NONE) {
            /*
             * Unit tests and substitution graphs can disable verification early on in the
             * compilation pipeline.
             */
            frameStateVerification = FrameStateVerification.NONE;
            return;
        }
        assert frameStateVerification.ordinal() < newFrameStateVerification.ordinal() : "Old verification " + frameStateVerification + " must imply new verification " + newFrameStateVerification +
                        ", i.e., verification can only be relaxed over the course of compilation";
        frameStateVerification = newFrameStateVerification;
    }

    public void disableFrameStateVerification() {
        weakenFrameStateVerification(FrameStateVerification.NONE);
    }

    public void clearAllStateAfter() {
        weakenFrameStateVerification(FrameStateVerification.NONE);
        for (Node node : getNodes()) {
            if (node instanceof StateSplit) {
                FrameState stateAfter = ((StateSplit) node).stateAfter();
                if (stateAfter != null) {
                    assert !(node instanceof ExceptionObjectNode) : "ExceptionObjects cannot have a null FrameState";
                    ((StateSplit) node).setStateAfter(null);
                    // 2 nodes referencing the same frame state
                    if (stateAfter.isAlive()) {
                        GraphUtil.killWithUnusedFloatingInputs(stateAfter);
                    }
                }
            }
        }
    }

    public boolean hasVirtualizableAllocation() {
        for (Node n : getNodes()) {
            if (n instanceof VirtualizableAllocation) {
                return true;
            }
        }
        return false;
    }

    @Override
    protected void afterRegister(Node node) {
        assert hasValueProxies() || !(node instanceof ValueProxyNode);
        if (GraalOptions.TraceInlining.getValue(getOptions())) {
            if (node instanceof Invokable) {
                ((Invokable) node).updateInliningLogAfterRegister(this);
            }
        }
    }

    public NodeSourcePosition getCallerContext() {
        return callerContext;
    }
}