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 * 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

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 * accompanied this code).

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 * You should have received a copy of the GNU General Public License version

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 *

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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2011 INRIA, France Telecom

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holders nor the names of its

 *    contributors may be used to endorse or promote products derived from

 *    this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package jdk.internal.org.objectweb.asm.tree.analysis;

import java.util.List;

import jdk.internal.org.objectweb.asm.Type;

import jdk.internal.org.objectweb.asm.tree.AbstractInsnNode;

/**

 * A semantic bytecode interpreter. More precisely, this interpreter only

 * manages the computation of values from other values: it does not manage the

 * transfer of values to or from the stack, and to or from the local variables.

 * This separation allows a generic bytecode {@link Analyzer} to work with

 * various semantic interpreters, without needing to duplicate the code to

 * simulate the transfer of values.

 *

 * @param <V>

 *            type of the Value used for the analysis.

 *

 * @author Eric Bruneton

 */

public abstract class Interpreter<V extends Value> {

    protected final int api;

    protected Interpreter(final int api) {

        this.api = api;

    }

    /**

     * Creates a new value that represents the given type.

     *

     * Called for method parameters (including <code>this</code>), exception

     * handler variable and with <code>null</code> type for variables reserved

     * by long and double types.

     *

     * @param type

     *            a primitive or reference type, or <tt>null</tt> to represent

     *            an uninitialized value.

     * @return a value that represents the given type. The size of the returned

     *         value must be equal to the size of the given type.

     */

    public abstract V newValue(Type type);

    /**

     * Interprets a bytecode instruction without arguments. This method is

     * called for the following opcodes:

     *

     * ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4,

     * ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0,

     * DCONST_1, BIPUSH, SIPUSH, LDC, JSR, GETSTATIC, NEW

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @return the result of the interpretation of the given instruction.

     * @throws AnalyzerException

     */

    public abstract V newOperation(AbstractInsnNode insn)

            throws AnalyzerException;

    /**

     * Interprets a bytecode instruction that moves a value on the stack or to

     * or from local variables. This method is called for the following opcodes:

     *

     * ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE,

     * ASTORE, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param value

     *            the value that must be moved by the instruction.

     * @return the result of the interpretation of the given instruction. The

     *         returned value must be <tt>equal</tt> to the given value.

     * @throws AnalyzerException

     */

    public abstract V copyOperation(AbstractInsnNode insn, V value)

            throws AnalyzerException;

    /**

     * Interprets a bytecode instruction with a single argument. This method is

     * called for the following opcodes:

     *

     * INEG, LNEG, FNEG, DNEG, IINC, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L,

     * F2D, D2I, D2L, D2F, I2B, I2C, I2S, IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE,

     * TABLESWITCH, LOOKUPSWITCH, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN,

     * PUTSTATIC, GETFIELD, NEWARRAY, ANEWARRAY, ARRAYLENGTH, ATHROW, CHECKCAST,

     * INSTANCEOF, MONITORENTER, MONITOREXIT, IFNULL, IFNONNULL

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param value

     *            the argument of the instruction to be interpreted.

     * @return the result of the interpretation of the given instruction.

     * @throws AnalyzerException

     */

    public abstract V unaryOperation(AbstractInsnNode insn, V value)

            throws AnalyzerException;

    /**

     * Interprets a bytecode instruction with two arguments. This method is

     * called for the following opcodes:

     *

     * IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IADD,

     * LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV,

     * LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, ISHL, LSHL, ISHR, LSHR, IUSHR,

     * LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, LCMP, FCMPL, FCMPG, DCMPL,

     * DCMPG, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,

     * IF_ACMPEQ, IF_ACMPNE, PUTFIELD

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param value1

     *            the first argument of the instruction to be interpreted.

     * @param value2

     *            the second argument of the instruction to be interpreted.

     * @return the result of the interpretation of the given instruction.

     * @throws AnalyzerException

     */

    public abstract V binaryOperation(AbstractInsnNode insn, V value1, V value2)

            throws AnalyzerException;

    /**

     * Interprets a bytecode instruction with three arguments. This method is

     * called for the following opcodes:

     *

     * IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param value1

     *            the first argument of the instruction to be interpreted.

     * @param value2

     *            the second argument of the instruction to be interpreted.

     * @param value3

     *            the third argument of the instruction to be interpreted.

     * @return the result of the interpretation of the given instruction.

     * @throws AnalyzerException

     */

    public abstract V ternaryOperation(AbstractInsnNode insn, V value1,

            V value2, V value3) throws AnalyzerException;

    /**

     * Interprets a bytecode instruction with a variable number of arguments.

     * This method is called for the following opcodes:

     *

     * INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC, INVOKEINTERFACE,

     * MULTIANEWARRAY and INVOKEDYNAMIC

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param values

     *            the arguments of the instruction to be interpreted.

     * @return the result of the interpretation of the given instruction.

     * @throws AnalyzerException

     */

    public abstract V naryOperation(AbstractInsnNode insn,

            List<? extends V> values) throws AnalyzerException;

    /**

     * Interprets a bytecode return instruction. This method is called for the

     * following opcodes:

     *

     * IRETURN, LRETURN, FRETURN, DRETURN, ARETURN

     *

     * @param insn

     *            the bytecode instruction to be interpreted.

     * @param value

     *            the argument of the instruction to be interpreted.

     * @param expected

     *            the expected return type of the analyzed method.

     * @throws AnalyzerException

     */

    public abstract void returnOperation(AbstractInsnNode insn, V value,

            V expected) throws AnalyzerException;

    /**

     * Merges two values. The merge operation must return a value that

     * represents both values (for instance, if the two values are two types,

     * the merged value must be a common super type of the two types. If the two

     * values are integer intervals, the merged value must be an interval that

     * contains the previous ones. Likewise for other types of values).

     *

     * @param v

     *            a value.

     * @param w

     *            another value.

     * @return the merged value. If the merged value is equal to <tt>v</tt>,

     *         this method <i>must</i> return <tt>v</tt>.

     */

    public abstract V merge(V v, V w);

}