/*

 * Copyright (c) 2015, 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.nodes.graphbuilderconf;

import static jdk.vm.ci.meta.DeoptimizationAction.InvalidateReprofile;

import static jdk.vm.ci.meta.DeoptimizationReason.NullCheckException;

import static org.graalvm.compiler.core.common.type.StampFactory.objectNonNull;

import org.graalvm.compiler.bytecode.Bytecode;

import org.graalvm.compiler.bytecode.BytecodeProvider;

import org.graalvm.compiler.core.common.type.AbstractPointerStamp;

import org.graalvm.compiler.core.common.type.ObjectStamp;

import org.graalvm.compiler.core.common.type.Stamp;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.core.common.type.StampPair;

import org.graalvm.compiler.nodes.CallTargetNode;

import org.graalvm.compiler.nodes.CallTargetNode.InvokeKind;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.FixedGuardNode;

import org.graalvm.compiler.nodes.LogicNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.PiNode;

import org.graalvm.compiler.nodes.StateSplit;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.calc.IsNullNode;

import org.graalvm.compiler.nodes.calc.NarrowNode;

import org.graalvm.compiler.nodes.calc.SignExtendNode;

import org.graalvm.compiler.nodes.calc.ZeroExtendNode;

import org.graalvm.compiler.nodes.type.StampTool;

import jdk.vm.ci.code.BailoutException;

import jdk.vm.ci.meta.Assumptions;

import jdk.vm.ci.meta.DeoptimizationAction;

import jdk.vm.ci.meta.DeoptimizationReason;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.JavaType;

import jdk.vm.ci.meta.ResolvedJavaMethod;

/**

 * Used by a {@link GraphBuilderPlugin} to interface with an object that parses the bytecode of a

 * single {@linkplain #getMethod() method} as part of building a {@linkplain #getGraph() graph} .

 */

public interface GraphBuilderContext extends GraphBuilderTool {

    /**

     * Pushes a given value to the frame state stack using an explicit kind. This should be used

     * when {@code value.getJavaKind()} is different from the kind that the bytecode instruction

     * currently being parsed pushes to the stack.

     *

     * @param kind the kind to use when type checking this operation

     * @param value the value to push to the stack. The value must already have been

     *            {@linkplain #append(ValueNode) appended}.

     */

    void push(JavaKind kind, ValueNode value);

    /**

     * Adds a node to the graph. If the node is in the graph, returns immediately. If the node is a

     * {@link StateSplit} with a null {@linkplain StateSplit#stateAfter() frame state}, the frame

     * state is initialized.

     *

     * @param value the value to add to the graph and push to the stack. The

     *            {@code value.getJavaKind()} kind is used when type checking this operation.

     * @return a node equivalent to {@code value} in the graph

     */

    default <T extends ValueNode> T add(T value) {

        if (value.graph() != null) {

            assert !(value instanceof StateSplit) || ((StateSplit) value).stateAfter() != null;

            return value;

        }

    }

    /**

     * Adds a node and its inputs to the graph. If the node is in the graph, returns immediately. If

     * the node is a {@link StateSplit} with a null {@linkplain StateSplit#stateAfter() frame state}

     * , the frame state is initialized.

     *

     * @param value the value to add to the graph and push to the stack. The

     *            {@code value.getJavaKind()} kind is used when type checking this operation.

     * @return a node equivalent to {@code value} in the graph

     */

    default <T extends ValueNode> T addWithInputs(T value) {

        if (value.graph() != null) {

            assert !(value instanceof StateSplit) || ((StateSplit) value).stateAfter() != null;

            return value;

        }

    }

    default ValueNode addNonNullCast(ValueNode value) {

        AbstractPointerStamp valueStamp = (AbstractPointerStamp) value.stamp(NodeView.DEFAULT);

        if (valueStamp.nonNull()) {

            return value;

        } else {

            LogicNode isNull = add(IsNullNode.create(value));

            FixedGuardNode fixedGuard = add(new FixedGuardNode(isNull, DeoptimizationReason.NullCheckException, DeoptimizationAction.None, true));

            Stamp newStamp = valueStamp.improveWith(StampFactory.objectNonNull());

            return add(PiNode.create(value, newStamp, fixedGuard));

        }

    }

    /**

     * Adds a node with a non-void kind to the graph, pushes it to the stack. If the returned node

     * is a {@link StateSplit} with a null {@linkplain StateSplit#stateAfter() frame state}, the

     * frame state is initialized.

     *

     * @param kind the kind to use when type checking this operation

     * @param value the value to add to the graph and push to the stack

     * @return a node equivalent to {@code value} in the graph

     */

    default <T extends ValueNode> T addPush(JavaKind kind, T value) {

        T equivalentValue = value.graph() != null ? value : append(value);

        push(kind, equivalentValue);

    }

    /**

     * Handles an invocation that a plugin determines can replace the original invocation (i.e., the

     * one for which the plugin was applied). This applies all standard graph builder processing to

     * the replaced invocation including applying any relevant plugins.

     *

     * @param invokeKind the kind of the replacement invocation

     * @param targetMethod the target of the replacement invocation

     * @param args the arguments to the replacement invocation

     * @param forceInlineEverything specifies if all invocations encountered in the scope of

     *            handling the replaced invoke are to be force inlined

     */

    void handleReplacedInvoke(InvokeKind invokeKind, ResolvedJavaMethod targetMethod, ValueNode[] args, boolean forceInlineEverything);

    void handleReplacedInvoke(CallTargetNode callTarget, JavaKind resultType);

    /**

     * Intrinsifies an invocation of a given method by inlining the bytecodes of a given

     * substitution method.

     *

     * @param bytecodeProvider used to get the bytecodes to parse for the substitution method

     * @param targetMethod the method being intrinsified

     * @param substitute the intrinsic implementation

     * @param receiver the receiver, or null for static methods

     * @param argsIncludingReceiver the arguments with which to inline the invocation

     *

     * @return whether the intrinsification was successful

     */

    boolean intrinsify(BytecodeProvider bytecodeProvider, ResolvedJavaMethod targetMethod, ResolvedJavaMethod substitute, InvocationPlugin.Receiver receiver, ValueNode[] argsIncludingReceiver);

    /**

     * Creates a snap shot of the current frame state with the BCI of the instruction after the one

     * currently being parsed and assigns it to a given {@linkplain StateSplit#hasSideEffect() side

     * effect} node.

     *

     * @param sideEffect a side effect node just appended to the graph

     */

    void setStateAfter(StateSplit sideEffect);

    /**

     * Gets the parsing context for the method that inlines the method being parsed by this context.

     */

    GraphBuilderContext getParent();

    /**

     * Gets the first ancestor parsing context that is not parsing a {@linkplain #parsingIntrinsic()

     * intrinsic}.

     */

    default GraphBuilderContext getNonIntrinsicAncestor() {

        GraphBuilderContext ancestor = getParent();

        while (ancestor != null && ancestor.parsingIntrinsic()) {

            ancestor = ancestor.getParent();

        }

        return ancestor;

    }

    /**

     * Gets the code being parsed.

     */

    Bytecode getCode();

    /**

     * Gets the method being parsed by this context.

     */

    ResolvedJavaMethod getMethod();

    /**

     * Gets the index of the bytecode instruction currently being parsed.

     */

    int bci();

    /**

     * Gets the kind of invocation currently being parsed.

     */

    InvokeKind getInvokeKind();

    /**

     * Gets the return type of the invocation currently being parsed.

     */

    JavaType getInvokeReturnType();

    default StampPair getInvokeReturnStamp(Assumptions assumptions) {

        JavaType returnType = getInvokeReturnType();

        return StampFactory.forDeclaredType(assumptions, returnType, false);

    }

    /**

     * Gets the inline depth of this context. A return value of 0 implies that this is the context

     * for the parse root.

     */

    default int getDepth() {

        GraphBuilderContext parent = getParent();

        int result = 0;

        while (parent != null) {

            result++;

            parent = parent.getParent();

        }

        return result;

    }

    /**

     * Determines if this parsing context is within the bytecode of an intrinsic or a method inlined

     * by an intrinsic.

     */

    @Override

    default boolean parsingIntrinsic() {

        return getIntrinsic() != null;

    }

    /**

     * Gets the intrinsic of the current parsing context or {@code null} if not

     * {@link #parsingIntrinsic() parsing an intrinsic}.

     */

    IntrinsicContext getIntrinsic();

    BailoutException bailout(String string);

    default ValueNode nullCheckedValue(ValueNode value) {

        return nullCheckedValue(value, InvalidateReprofile);

    }

    /**

     * Gets a version of a given value that has a {@linkplain StampTool#isPointerNonNull(ValueNode)

     * non-null} stamp.

     */

    default ValueNode nullCheckedValue(ValueNode value, DeoptimizationAction action) {

        if (!StampTool.isPointerNonNull(value)) {

            LogicNode condition = getGraph().unique(IsNullNode.create(value));

            ObjectStamp receiverStamp = (ObjectStamp) value.stamp(NodeView.DEFAULT);

            Stamp stamp = receiverStamp.join(objectNonNull());

            FixedGuardNode fixedGuard = append(new FixedGuardNode(condition, NullCheckException, action, true));

            ValueNode nonNullReceiver = getGraph().addOrUniqueWithInputs(PiNode.create(value, stamp, fixedGuard));

            // TODO: Propogating the non-null into the frame state would

            // remove subsequent null-checks on the same value. However,

            // it currently causes an assertion failure when merging states.

            //

            // frameState.replace(value, nonNullReceiver);

            return nonNullReceiver;

        }

        return value;

    }

    @SuppressWarnings("unused")

    default void notifyReplacedCall(ResolvedJavaMethod targetMethod, ConstantNode node) {

    }

    /**

     * Interface whose instances hold inlining information about the current context, in a wider

     * sense. The wider sense in this case concerns graph building approaches that don't necessarily

     * keep a chain of {@link GraphBuilderContext} instances normally available through

     * {@linkplain #getParent()}. Examples of such approaches are partial evaluation and incremental

     * inlining.

     */

    interface ExternalInliningContext {

        int getInlinedDepth();

    }

    default ExternalInliningContext getExternalInliningContext() {

        return null;

    }

    /**

     * Adds masking to a given subword value according to a given {@Link JavaKind}, such that the

     * masked value falls in the range of the given kind. In the cases where the given kind is not a

     * subword kind, the input value is returned immediately.

     *

     * @param value the value to be masked

     * @param kind the kind that specifies the range of the masked value

     * @return the masked value

     */

    default ValueNode maskSubWordValue(ValueNode value, JavaKind kind) {

        if (kind == kind.getStackKind()) {

            return value;

        }

        // Subword value

        ValueNode narrow = append(NarrowNode.create(value, kind.getBitCount(), NodeView.DEFAULT));

        if (kind.isUnsigned()) {

            return append(ZeroExtendNode.create(narrow, 32, NodeView.DEFAULT));

        } else {

            return append(SignExtendNode.create(narrow, 32, NodeView.DEFAULT));

        }

    }

}