/*

 * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.codegen;

import java.util.List;

import java.util.Map;

import jdk.nashorn.internal.ir.AccessNode;

import jdk.nashorn.internal.ir.BinaryNode;

import jdk.nashorn.internal.ir.Block;

import jdk.nashorn.internal.ir.BreakNode;

import jdk.nashorn.internal.ir.CallNode;

import jdk.nashorn.internal.ir.CatchNode;

import jdk.nashorn.internal.ir.ContinueNode;

import jdk.nashorn.internal.ir.ExpressionStatement;

import jdk.nashorn.internal.ir.ForNode;

import jdk.nashorn.internal.ir.FunctionNode;

import jdk.nashorn.internal.ir.IdentNode;

import jdk.nashorn.internal.ir.IfNode;

import jdk.nashorn.internal.ir.IndexNode;

import jdk.nashorn.internal.ir.JumpToInlinedFinally;

import jdk.nashorn.internal.ir.LexicalContext;

import jdk.nashorn.internal.ir.LiteralNode;

import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode;

import jdk.nashorn.internal.ir.Node;

import jdk.nashorn.internal.ir.ObjectNode;

import jdk.nashorn.internal.ir.PropertyNode;

import jdk.nashorn.internal.ir.ReturnNode;

import jdk.nashorn.internal.ir.RuntimeNode;

import jdk.nashorn.internal.ir.SplitNode;

import jdk.nashorn.internal.ir.Splittable;

import jdk.nashorn.internal.ir.SwitchNode;

import jdk.nashorn.internal.ir.ThrowNode;

import jdk.nashorn.internal.ir.TryNode;

import jdk.nashorn.internal.ir.UnaryNode;

import jdk.nashorn.internal.ir.VarNode;

import jdk.nashorn.internal.ir.WhileNode;

import jdk.nashorn.internal.ir.WithNode;

import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor;

/**

 * Computes the "byte code" weight of an AST segment. This is used

 * for Splitting too large class files

 */

final class WeighNodes extends NodeOperatorVisitor<LexicalContext> {

    /*

     * Weight constants.

     */

    static final long FUNCTION_WEIGHT  = 40;

    static final long AASTORE_WEIGHT   =  2;

    static final long ACCESS_WEIGHT    =  4;

    static final long ADD_WEIGHT       = 10;

    static final long BREAK_WEIGHT     =  1;

    static final long CALL_WEIGHT      = 10;

    static final long CATCH_WEIGHT     = 10;

    static final long COMPARE_WEIGHT   =  6;

    static final long CONTINUE_WEIGHT  =  1;

    static final long IF_WEIGHT        =  2;

    static final long LITERAL_WEIGHT   = 10;

    static final long LOOP_WEIGHT      =  4;

    static final long NEW_WEIGHT       =  6;

    static final long FUNC_EXPR_WEIGHT = 20;

    static final long RETURN_WEIGHT    =  2;

    static final long SPLIT_WEIGHT     = 40;

    static final long SWITCH_WEIGHT    =  8;

    static final long THROW_WEIGHT     =  2;

    static final long VAR_WEIGHT       = 40;

    static final long WITH_WEIGHT      =  8;

    static final long OBJECT_WEIGHT    = 16;

    static final long SETPROP_WEIGHT   =  5;

    /** Accumulated weight. */

    private long weight;

    /** Optional cache for weight of block nodes. */

    private final Map<Node, Long> weightCache;

    private final FunctionNode topFunction;

    /**

     * Constructor

     *

     * @param weightCache cache of already calculated block weights

     */

    private WeighNodes(final FunctionNode topFunction, final Map<Node, Long> weightCache) {

        super(new LexicalContext());

        this.topFunction = topFunction;

        this.weightCache = weightCache;

    }

    static long weigh(final Node node) {

        return weigh(node, null);

    }

    static long weigh(final Node node, final Map<Node, Long> weightCache) {

        final WeighNodes weighNodes = new WeighNodes(node instanceof FunctionNode ? (FunctionNode)node : null, weightCache);

        node.accept(weighNodes);

        return weighNodes.weight;

    }

    @Override

    public Node leaveAccessNode(final AccessNode accessNode) {

        weight += ACCESS_WEIGHT;

        return accessNode;

    }

    @Override

    public boolean enterBlock(final Block block) {

        if (weightCache != null && weightCache.containsKey(block)) {

            weight += weightCache.get(block);

            return false;

        }

        return true;

    }

    @Override

    public Node leaveBreakNode(final BreakNode breakNode) {

        weight += BREAK_WEIGHT;

        return breakNode;

    }

    @Override

    public Node leaveCallNode(final CallNode callNode) {

        weight += CALL_WEIGHT;

        return callNode;

    }

    @Override

    public Node leaveCatchNode(final CatchNode catchNode) {

        weight += CATCH_WEIGHT;

        return catchNode;

    }

    @Override

    public Node leaveContinueNode(final ContinueNode continueNode) {

        weight += CONTINUE_WEIGHT;

        return continueNode;

    }

    @Override

    public Node leaveExpressionStatement(final ExpressionStatement expressionStatement) {

        return expressionStatement;

    }

    @Override

    public Node leaveForNode(final ForNode forNode) {

        weight += LOOP_WEIGHT;

        return forNode;

    }

    @Override

    public boolean enterFunctionNode(final FunctionNode functionNode) {

        if (functionNode == topFunction) {

            // the function being weighted; descend into its statements

            return true;

        }

        // just a reference to inner function from outer function

        weight += FUNC_EXPR_WEIGHT;

        return false;

    }

    @Override

    public Node leaveIdentNode(final IdentNode identNode) {

        weight += ACCESS_WEIGHT;

        return identNode;

    }

    @Override

    public Node leaveIfNode(final IfNode ifNode) {

        weight += IF_WEIGHT;

        return ifNode;

    }

    @Override

    public Node leaveIndexNode(final IndexNode indexNode) {

        weight += ACCESS_WEIGHT;

        return indexNode;

    }

    @Override

    public Node leaveJumpToInlinedFinally(final JumpToInlinedFinally jumpToInlinedFinally) {

        weight += BREAK_WEIGHT;

        return jumpToInlinedFinally;

    }

    @SuppressWarnings("rawtypes")

    @Override

    public boolean enterLiteralNode(final LiteralNode literalNode) {

        weight += LITERAL_WEIGHT;

        if (literalNode instanceof ArrayLiteralNode) {

            final ArrayLiteralNode arrayLiteralNode = (ArrayLiteralNode)literalNode;

            final Node[]           value            = arrayLiteralNode.getValue();

            final int[]            postsets         = arrayLiteralNode.getPostsets();

            final List<Splittable.SplitRange>  units            = arrayLiteralNode.getSplitRanges();

            if (units == null) {

                for (final int postset : postsets) {

                    weight += AASTORE_WEIGHT;

                    final Node element = value[postset];

                    if (element != null) {

                        element.accept(this);

                    }

                }

            }

            return false;

        }

        return true;

    }

    @Override

    public boolean enterObjectNode(final ObjectNode objectNode) {

        weight += OBJECT_WEIGHT;

        final List<PropertyNode> properties = objectNode.getElements();

        final boolean isSpillObject = properties.size() > CodeGenerator.OBJECT_SPILL_THRESHOLD;

        for (final PropertyNode property : properties) {

            if (!LiteralNode.isConstant(property.getValue())) {

                weight += SETPROP_WEIGHT;

                property.getValue().accept(this);

            } else if (!isSpillObject) {

                // constants in spill object are set via preset spill array,

                // but fields objects need to set constants.

                weight += SETPROP_WEIGHT;

            }

        }

        return false;

    }

    @Override

    public Node leavePropertyNode(final PropertyNode propertyNode) {

        weight += LITERAL_WEIGHT;

        return propertyNode;

    }

    @Override

    public Node leaveReturnNode(final ReturnNode returnNode) {

        weight += RETURN_WEIGHT;

        return returnNode;

    }

    @Override

    public Node leaveRuntimeNode(final RuntimeNode runtimeNode) {

        weight += CALL_WEIGHT;

        return runtimeNode;

    }

    @Override

    public boolean enterSplitNode(final SplitNode splitNode) {

        weight += SPLIT_WEIGHT;

        return false;

    }

    @Override

    public Node leaveSwitchNode(final SwitchNode switchNode) {

        weight += SWITCH_WEIGHT;

        return switchNode;

    }

    @Override

    public Node leaveThrowNode(final ThrowNode throwNode) {

        weight += THROW_WEIGHT;

        return throwNode;

    }

    @Override

    public Node leaveTryNode(final TryNode tryNode) {

        weight += THROW_WEIGHT;

        return tryNode;

    }

    @Override

    public Node leaveVarNode(final VarNode varNode) {

        weight += VAR_WEIGHT;

        return varNode;

    }

    @Override

    public Node leaveWhileNode(final WhileNode whileNode) {

        weight += LOOP_WEIGHT;

        return whileNode;

    }

    @Override

    public Node leaveWithNode(final WithNode withNode) {

        weight += WITH_WEIGHT;

        return withNode;

    }

    @Override

    public Node leavePOS(final UnaryNode unaryNode) {

        return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveBIT_NOT(final UnaryNode unaryNode) {

        return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveDECINC(final UnaryNode unaryNode) {

         return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveDELETE(final UnaryNode unaryNode) {

        return runtimeNodeWeight(unaryNode);

    }

    @Override

    public Node leaveNEW(final UnaryNode unaryNode) {

        weight += NEW_WEIGHT;

        return unaryNode;

    }

    @Override

    public Node leaveNOT(final UnaryNode unaryNode) {

        return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveNEG(final UnaryNode unaryNode) {

        return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveTYPEOF(final UnaryNode unaryNode) {

        return runtimeNodeWeight(unaryNode);

    }

    @Override

    public Node leaveVOID(final UnaryNode unaryNode) {

        return unaryNodeWeight(unaryNode);

    }

    @Override

    public Node leaveADD(final BinaryNode binaryNode) {

        weight += ADD_WEIGHT;

        return binaryNode;

    }

    @Override

    public Node leaveAND(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_ADD(final BinaryNode binaryNode) {

        weight += ADD_WEIGHT;

        return binaryNode;

    }

    @Override

    public Node leaveASSIGN_BIT_AND(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_BIT_OR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_BIT_XOR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_DIV(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_MOD(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_MUL(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_SAR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_SHL(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_SHR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveASSIGN_SUB(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveARROW(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveBIT_AND(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveBIT_OR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveBIT_XOR(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveCOMMARIGHT(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveDIV(final BinaryNode binaryNode) {

        return binaryNodeWeight(binaryNode);

    }

    @Override

    public Node leaveEQ(final BinaryNode binaryNode) {

        return compareWeight(binaryNode);

    }

    @Override

    public Node leaveEQ_STRICT(final BinaryNode binaryNode) {

        return compareWeight(binaryNode);

    }

    @Override

    public Node leaveGE(final BinaryNode binaryNode) {

        return compareWeight(binaryNode);

    }

    @Override

    public Node leaveGT(final BinaryNode binaryNode) {

        return compareWeight(binaryNode);

    }

    @Override

    public Node leaveIN(final BinaryNode binaryNode) {

        weight += CALL_WEIGHT;

        return binaryNode;

    }

    @Override

    public Node leaveINSTANCEOF(final BinaryNode binaryNode) {

        weight += CALL_WEIGHT;

        return binaryNode;

    }

    @Override

    public Node leaveLE(final BinaryNode binaryNode) {

        return compareWeight(binaryNode);