/*

 * Copyright (c) 2011, 2016, 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.

 *

 * 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.replacements;

import static org.graalvm.compiler.core.common.GraalOptions.UseSnippetGraphCache;

import static org.graalvm.compiler.debug.DebugContext.DEFAULT_LOG_STREAM;

import static org.graalvm.compiler.java.BytecodeParserOptions.InlineDuringParsing;

import static org.graalvm.compiler.java.BytecodeParserOptions.InlineIntrinsicsDuringParsing;

import static org.graalvm.compiler.nodes.graphbuilderconf.InlineInvokePlugin.InlineInfo.createIntrinsicInlineInfo;

import static org.graalvm.compiler.nodes.graphbuilderconf.IntrinsicContext.CompilationContext.INLINE_AFTER_PARSING;

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

import java.util.Collections;

import java.util.List;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentMap;

import java.util.concurrent.atomic.AtomicInteger;

import org.graalvm.compiler.api.replacements.Fold;

import org.graalvm.compiler.api.replacements.MethodSubstitution;

import org.graalvm.compiler.api.replacements.Snippet;

import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;

import org.graalvm.compiler.api.replacements.SnippetTemplateCache;

import org.graalvm.compiler.bytecode.Bytecode;

import org.graalvm.compiler.bytecode.BytecodeProvider;

import org.graalvm.compiler.bytecode.ResolvedJavaMethodBytecode;

import org.graalvm.compiler.core.common.GraalOptions;

import org.graalvm.compiler.core.common.spi.ConstantFieldProvider;

import org.graalvm.compiler.debug.DebugCloseable;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.DebugContext.Description;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.debug.TimerKey;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.Node.NodeIntrinsic;

import org.graalvm.compiler.java.GraphBuilderPhase;

import org.graalvm.compiler.java.GraphBuilderPhase.Instance;

import org.graalvm.compiler.nodes.CallTargetNode;

import org.graalvm.compiler.nodes.Invoke;

import org.graalvm.compiler.nodes.StateSplit;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.graphbuilderconf.GeneratedInvocationPlugin;

import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;

import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration.Plugins;

import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderContext;

import org.graalvm.compiler.nodes.graphbuilderconf.InlineInvokePlugin;

import org.graalvm.compiler.nodes.graphbuilderconf.IntrinsicContext;

import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin;

import org.graalvm.compiler.nodes.graphbuilderconf.MethodSubstitutionPlugin;

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

import org.graalvm.compiler.nodes.spi.Replacements;

import org.graalvm.compiler.nodes.spi.StampProvider;

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.compiler.phases.OptimisticOptimizations;

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

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

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

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

import org.graalvm.compiler.phases.util.Providers;

import org.graalvm.compiler.word.Word;

import org.graalvm.compiler.word.WordOperationPlugin;

import jdk.vm.ci.code.TargetDescription;

import jdk.vm.ci.meta.ConstantReflectionProvider;

import jdk.vm.ci.meta.MetaAccessProvider;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

public class ReplacementsImpl implements Replacements, InlineInvokePlugin {

    protected final OptionValues options;

    public final Providers providers;

    public final SnippetReflectionProvider snippetReflection;

    public final TargetDescription target;

    private GraphBuilderConfiguration.Plugins graphBuilderPlugins;

    private final DebugHandlersFactory debugHandlersFactory;

    @Override

    public OptionValues getOptions() {

        return options;

    }

    /**

     * The preprocessed replacement graphs.

     */

    protected final ConcurrentMap<ResolvedJavaMethod, StructuredGraph> graphs;

    /**

     * The default {@link BytecodeProvider} to use for accessing the bytecode of a replacement if

     * the replacement doesn't provide another {@link BytecodeProvider}.

     */

    protected final BytecodeProvider defaultBytecodeProvider;

    public void setGraphBuilderPlugins(GraphBuilderConfiguration.Plugins plugins) {

        assert this.graphBuilderPlugins == null;

        this.graphBuilderPlugins = plugins;

    }

    @Override

    public GraphBuilderConfiguration.Plugins getGraphBuilderPlugins() {

        return graphBuilderPlugins;

    }

    protected boolean hasGeneratedInvocationPluginAnnotation(ResolvedJavaMethod method) {

        return method.getAnnotation(Node.NodeIntrinsic.class) != null || method.getAnnotation(Fold.class) != null;

    }

    protected boolean hasGenericInvocationPluginAnnotation(ResolvedJavaMethod method) {

        return method.getAnnotation(Word.Operation.class) != null;

    }

    private static final int MAX_GRAPH_INLINING_DEPTH = 100; // more than enough

    /**

     * Determines whether a given method should be inlined based on whether it has a substitution or

     * whether the inlining context is already within a substitution.

     *

     * @return an object specifying how {@code method} is to be inlined or null if it should not be

     *         inlined based on substitution related criteria

     */

    @Override

    public InlineInfo shouldInlineInvoke(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode[] args) {

        Bytecode subst = getSubstitutionBytecode(method);

        if (subst != null) {

            if (b.parsingIntrinsic() || InlineDuringParsing.getValue(b.getOptions()) || InlineIntrinsicsDuringParsing.getValue(b.getOptions())) {

                // Forced inlining of intrinsics

                return createIntrinsicInlineInfo(subst.getMethod(), subst.getOrigin());

            }

            return null;

        }

        if (b.parsingIntrinsic()) {

            assert b.getDepth() < MAX_GRAPH_INLINING_DEPTH : "inlining limit exceeded";

            // Force inlining when parsing replacements

            return createIntrinsicInlineInfo(method, defaultBytecodeProvider);

        } else {

            assert method.getAnnotation(NodeIntrinsic.class) == null : String.format("@%s method %s must only be called from within a replacement%n%s", NodeIntrinsic.class.getSimpleName(),

                            method.format("%h.%n"), b);

        }

        return null;

    }

    @Override

    public void notifyNotInlined(GraphBuilderContext b, ResolvedJavaMethod method, Invoke invoke) {

        if (b.parsingIntrinsic()) {

            IntrinsicContext intrinsic = b.getIntrinsic();

            if (!intrinsic.isCallToOriginal(method)) {

                if (hasGeneratedInvocationPluginAnnotation(method)) {

                    throw new GraalError("%s should have been handled by a %s", method.format("%H.%n(%p)"), GeneratedInvocationPlugin.class.getSimpleName());

                }

                if (hasGenericInvocationPluginAnnotation(method)) {

                    throw new GraalError("%s should have been handled by %s", method.format("%H.%n(%p)"), WordOperationPlugin.class.getSimpleName());

                }

                throw new GraalError("All non-recursive calls in the intrinsic %s must be inlined or intrinsified: found call to %s",

                                intrinsic.getIntrinsicMethod().format("%H.%n(%p)"), method.format("%h.%n(%p)"));

            }

        }

    }

    // This map is key'ed by a class name instead of a Class object so that

    // it is stable across VM executions (in support of replay compilation).

    private final EconomicMap<String, SnippetTemplateCache> snippetTemplateCache;

    public ReplacementsImpl(OptionValues options, DebugHandlersFactory debugHandlersFactory, Providers providers, SnippetReflectionProvider snippetReflection, BytecodeProvider bytecodeProvider,

                    TargetDescription target) {

        this.options = options;

        this.providers = providers.copyWith(this);

        this.snippetReflection = snippetReflection;

        this.target = target;

        this.graphs = new ConcurrentHashMap<>();

        this.snippetTemplateCache = EconomicMap.create(Equivalence.DEFAULT);

        this.defaultBytecodeProvider = bytecodeProvider;

        this.debugHandlersFactory = debugHandlersFactory;

    }

    private static final TimerKey SnippetPreparationTime = DebugContext.timer("SnippetPreparationTime");

    @Override

    public StructuredGraph getSnippet(ResolvedJavaMethod method, Object[] args) {

        return getSnippet(method, null, args);

    }

    private static final AtomicInteger nextDebugContextId = new AtomicInteger();

    protected DebugContext openDebugContext(String idPrefix, ResolvedJavaMethod method) {

        DebugContext outer = DebugContext.forCurrentThread();

        Description description = new Description(method, idPrefix + nextDebugContextId.incrementAndGet());

        List<DebugHandlersFactory> factories = debugHandlersFactory == null ? Collections.emptyList() : Collections.singletonList(debugHandlersFactory);

        return DebugContext.create(options, description, outer.getGlobalMetrics(), DEFAULT_LOG_STREAM, factories);

    }

    @Override

    @SuppressWarnings("try")

    public StructuredGraph getSnippet(ResolvedJavaMethod method, ResolvedJavaMethod recursiveEntry, Object[] args) {

        assert method.getAnnotation(Snippet.class) != null : "Snippet must be annotated with @" + Snippet.class.getSimpleName();

        assert method.hasBytecodes() : "Snippet must not be abstract or native";

        StructuredGraph graph = UseSnippetGraphCache.getValue(options) ? graphs.get(method) : null;

        if (graph == null) {

            try (DebugContext debug = openDebugContext("Snippet_", method);

                            DebugCloseable a = SnippetPreparationTime.start(debug)) {

                StructuredGraph newGraph = makeGraph(debug, defaultBytecodeProvider, method, args, recursiveEntry);

                DebugContext.counter("SnippetNodeCount[%#s]", method).add(newGraph.getDebug(), newGraph.getNodeCount());

                if (!UseSnippetGraphCache.getValue(options) || args != null) {

                    return newGraph;

                }

                newGraph.freeze();

                graphs.putIfAbsent(method, newGraph);

                graph = graphs.get(method);

            }

        }

        return graph;

    }

    @Override

    public void registerSnippet(ResolvedJavaMethod method) {

        // No initialization needed as snippet graphs are created on demand in getSnippet

    }

    @Override

    public boolean hasSubstitution(ResolvedJavaMethod method, int invokeBci) {

        InvocationPlugin plugin = graphBuilderPlugins.getInvocationPlugins().lookupInvocation(method);

        return plugin != null && (!plugin.inlineOnly() || invokeBci >= 0);

    }

    @Override

    public BytecodeProvider getDefaultReplacementBytecodeProvider() {

        return defaultBytecodeProvider;

    }

    @Override

    public Bytecode getSubstitutionBytecode(ResolvedJavaMethod method) {

        InvocationPlugin plugin = graphBuilderPlugins.getInvocationPlugins().lookupInvocation(method);

        if (plugin instanceof MethodSubstitutionPlugin) {

            MethodSubstitutionPlugin msPlugin = (MethodSubstitutionPlugin) plugin;

            ResolvedJavaMethod substitute = msPlugin.getSubstitute(providers.getMetaAccess());

            return msPlugin.getBytecodeProvider().getBytecode(substitute);

        }

        return null;

    }

    @Override

    public StructuredGraph getSubstitution(ResolvedJavaMethod method, int invokeBci) {

        StructuredGraph result;

        InvocationPlugin plugin = graphBuilderPlugins.getInvocationPlugins().lookupInvocation(method);

        if (plugin != null && (!plugin.inlineOnly() || invokeBci >= 0)) {

            MetaAccessProvider metaAccess = providers.getMetaAccess();

            if (plugin instanceof MethodSubstitutionPlugin) {

                MethodSubstitutionPlugin msPlugin = (MethodSubstitutionPlugin) plugin;

                ResolvedJavaMethod substitute = msPlugin.getSubstitute(metaAccess);

                if (graph == null) {

                    try (DebugContext debug = openDebugContext("Substitution_", method)) {

                        graph = makeGraph(debug, msPlugin.getBytecodeProvider(), substitute, null, method);

                        graph.freeze();

                        graphs.putIfAbsent(substitute, graph);

                        graph = graphs.get(substitute);

                    }

                }

                assert graph.isFrozen();

                result = graph;

            } else {

                Bytecode code = new ResolvedJavaMethodBytecode(method);

                ConstantReflectionProvider constantReflection = providers.getConstantReflection();

                ConstantFieldProvider constantFieldProvider = providers.getConstantFieldProvider();

                StampProvider stampProvider = providers.getStampProvider();

                try (DebugContext debug = openDebugContext("Substitution_", method)) {

                    result = new IntrinsicGraphBuilder(options, debug, metaAccess, constantReflection, constantFieldProvider, stampProvider, code, invokeBci).buildGraph(plugin);

                }

            }

        } else {

            result = null;

        }

        return result;

    }

    /**

     * Creates a preprocessed graph for a snippet or method substitution.

     *

     * @param bytecodeProvider how to access the bytecode of {@code method}

     * @param method the snippet or method substitution for which a graph will be created

     * @param args

     * @param original the original method if {@code method} is a {@linkplain MethodSubstitution

     *            substitution} otherwise null

     */

    public StructuredGraph makeGraph(DebugContext debug, BytecodeProvider bytecodeProvider, ResolvedJavaMethod method, Object[] args, ResolvedJavaMethod original) {

        return createGraphMaker(method, original).makeGraph(debug, bytecodeProvider, args);

    }

    /**

     * Can be overridden to return an object that specializes various parts of graph preprocessing.

     */

    protected GraphMaker createGraphMaker(ResolvedJavaMethod substitute, ResolvedJavaMethod original) {

        return new GraphMaker(this, substitute, original);

    }

    /**

     * Creates and preprocesses a graph for a replacement.

     */

    public static class GraphMaker {

        /** The replacements object that the graphs are created for. */

        protected final ReplacementsImpl replacements;

        /**

         * The method for which a graph is being created.

         */

        protected final ResolvedJavaMethod method;

        /**

         * The original method which {@link #method} is substituting. Calls to {@link #method} or

         * {@link #substitutedMethod} will be replaced with a forced inline of

         * {@link #substitutedMethod}.

         */

        protected final ResolvedJavaMethod substitutedMethod;

        protected GraphMaker(ReplacementsImpl replacements, ResolvedJavaMethod substitute, ResolvedJavaMethod substitutedMethod) {

            this.replacements = replacements;

            this.method = substitute;

            this.substitutedMethod = substitutedMethod;

        }

        @SuppressWarnings("try")

        public StructuredGraph makeGraph(DebugContext debug, BytecodeProvider bytecodeProvider, Object[] args) {

            try (DebugContext.Scope s = debug.scope("BuildSnippetGraph", method)) {

                assert method.hasBytecodes() : method;

                StructuredGraph graph = buildInitialGraph(debug, bytecodeProvider, method, args);

                finalizeGraph(graph);

                debug.dump(DebugContext.INFO_LEVEL, graph, "%s: Final", method.getName());

                return graph;

            } catch (Throwable e) {

                throw debug.handle(e);

            }

        }

        /**

         * Does final processing of a snippet graph.

         */

        protected void finalizeGraph(StructuredGraph graph) {

            if (!GraalOptions.SnippetCounters.getValue(replacements.options) || graph.getNodes().filter(SnippetCounterNode.class).isEmpty()) {

                int sideEffectCount = 0;

                assert (sideEffectCount = graph.getNodes().filter(e -> hasSideEffect(e)).count()) >= 0;

                new ConvertDeoptimizeToGuardPhase().apply(graph, null);

                assert sideEffectCount == graph.getNodes().filter(e -> hasSideEffect(e)).count() : "deleted side effecting node";

                new DeadCodeEliminationPhase(Required).apply(graph);

            } else {

                // ConvertDeoptimizeToGuardPhase will eliminate snippet counters on paths

                // that terminate in a deopt so we disable it if the graph contains

                // snippet counters. The trade off is that we miss out on guard

                // coalescing opportunities.

            }

        }

        /**

         * Filter nodes which have side effects and shouldn't be deleted from snippets when

         * converting deoptimizations to guards. Currently this only allows exception constructors

         * to be eliminated to cover the case when Java assertions are in the inlined code.

         *

         * @param node

         * @return true for nodes that have side effects and are unsafe to delete

         */

        private boolean hasSideEffect(Node node) {

            if (node instanceof StateSplit) {

                if (((StateSplit) node).hasSideEffect()) {

                    if (node instanceof Invoke) {

                        CallTargetNode callTarget = ((Invoke) node).callTarget();

                        if (callTarget instanceof MethodCallTargetNode) {

                            ResolvedJavaMethod targetMethod = ((MethodCallTargetNode) callTarget).targetMethod();

                            if (targetMethod.isConstructor()) {

                                ResolvedJavaType throwableType = replacements.providers.getMetaAccess().lookupJavaType(Throwable.class);

                                return !throwableType.isAssignableFrom(targetMethod.getDeclaringClass());

                            }

                        }

                    }

                    // Not an exception constructor call

                    return true;

                }

            }

            // Not a StateSplit

            return false;

        }

        /**

         * Builds the initial graph for a replacement.

         */

        @SuppressWarnings("try")

        protected StructuredGraph buildInitialGraph(DebugContext debug, BytecodeProvider bytecodeProvider, final ResolvedJavaMethod methodToParse, Object[] args) {

            // Replacements cannot have optimistic assumptions since they have

            // to be valid for the entire run of the VM.

            final StructuredGraph graph = new StructuredGraph.Builder(replacements.options, debug).method(methodToParse).build();

            // Replacements are not user code so they do not participate in unsafe access

            // tracking

            graph.disableUnsafeAccessTracking();

            try (DebugContext.Scope s = debug.scope("buildInitialGraph", graph)) {

                MetaAccessProvider metaAccess = replacements.providers.getMetaAccess();

                Plugins plugins = new Plugins(replacements.graphBuilderPlugins);

                GraphBuilderConfiguration config = GraphBuilderConfiguration.getSnippetDefault(plugins);

                if (args != null) {

                    plugins.prependParameterPlugin(new ConstantBindingParameterPlugin(args, metaAccess, replacements.snippetReflection));

                }

                IntrinsicContext initialIntrinsicContext = null;

                Snippet snippetAnnotation = method.getAnnotation(Snippet.class);

                if (snippetAnnotation == null) {

                    // Post-parse inlined intrinsic

                    initialIntrinsicContext = new IntrinsicContext(substitutedMethod, method, bytecodeProvider, INLINE_AFTER_PARSING);

                } else {

                    // Snippet

                    ResolvedJavaMethod original = substitutedMethod != null ? substitutedMethod : method;

                    initialIntrinsicContext = new IntrinsicContext(original, method, bytecodeProvider, INLINE_AFTER_PARSING, snippetAnnotation.allowPartialIntrinsicArgumentMismatch());

                }

                createGraphBuilder(metaAccess, replacements.providers.getStampProvider(), replacements.providers.getConstantReflection(), replacements.providers.getConstantFieldProvider(), config,

                                OptimisticOptimizations.NONE, initialIntrinsicContext).apply(graph);

                new CanonicalizerPhase().apply(graph, new PhaseContext(replacements.providers));

            } catch (Throwable e) {

                throw debug.handle(e);

            }

            return graph;

        }

        protected Instance createGraphBuilder(MetaAccessProvider metaAccess, StampProvider stampProvider, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider,

                        GraphBuilderConfiguration graphBuilderConfig, OptimisticOptimizations optimisticOpts, IntrinsicContext initialIntrinsicContext) {

            return new GraphBuilderPhase.Instance(metaAccess, stampProvider, constantReflection, constantFieldProvider, graphBuilderConfig, optimisticOpts,

                            initialIntrinsicContext);

        }

    }

    @Override

    public void registerSnippetTemplateCache(SnippetTemplateCache templates) {

        assert snippetTemplateCache.get(templates.getClass().getName()) == null;

        snippetTemplateCache.put(templates.getClass().getName(), templates);

    }

    @Override

    public <T extends SnippetTemplateCache> T getSnippetTemplateCache(Class<T> templatesClass) {

        SnippetTemplateCache ret = snippetTemplateCache.get(templatesClass.getName());

        return templatesClass.cast(ret);

    }

}