https://openjdk.java.net/ 
/*
 * 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.
 */

/*
 * 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.HashSet;
import java.util.List;
import java.util.Set;
import jdk.internal.org.objectweb.asm.Opcodes;
import jdk.internal.org.objectweb.asm.Type;
import jdk.internal.org.objectweb.asm.tree.AbstractInsnNode;
import jdk.internal.org.objectweb.asm.tree.FieldInsnNode;
import jdk.internal.org.objectweb.asm.tree.InvokeDynamicInsnNode;
import jdk.internal.org.objectweb.asm.tree.LdcInsnNode;
import jdk.internal.org.objectweb.asm.tree.MethodInsnNode;


An Interpreter for SourceValue values. 
Author:Eric Bruneton
/**
 * An {@link Interpreter} for {@link SourceValue} values.
 *
 * @author Eric Bruneton
 */
public class SourceInterpreter extends Interpreter<SourceValue> implements Opcodes {

    
Constructs a new SourceInterpreter for the latest ASM API version. Subclasses must
not use this constructor. Instead, they must use the SourceInterpreter(int) version. 
/**
      * Constructs a new {@link SourceInterpreter} for the latest ASM API version. <i>Subclasses must
      * not use this constructor</i>. Instead, they must use the {@link #SourceInterpreter(int)}
      * version.
      */
    public SourceInterpreter() {
        super(/* latest api = */ ASM8);
        if (getClass() != SourceInterpreter.class) {
            throw new IllegalStateException();
        }
    }

    
Constructs a new SourceInterpreter. 
Params:
/**
      * Constructs a new {@link SourceInterpreter}.
      *
      * @param api the ASM API version supported by this interpreter. Must be one of {@link
      *     jdk.internal.org.objectweb.asm.Opcodes#ASM4}, {@link jdk.internal.org.objectweb.asm.Opcodes#ASM5}, {@link
      *     jdk.internal.org.objectweb.asm.Opcodes#ASM6}, {@link jdk.internal.org.objectweb.asm.Opcodes#ASM7} or {@link
      *     jdk.internal.org.objectweb.asm.Opcodes#ASM8}.
      */
    protected SourceInterpreter(final int api) {
        super(api);
    }

    @Override
    public SourceValue newValue(final Type type) {
        if (type == Type.VOID_TYPE) {
            return null;
        }
        return new SourceValue(type == null ? 1 : type.getSize());
    }

    @Override
    public SourceValue newOperation(final AbstractInsnNode insn) {
        int size;
        switch (insn.getOpcode()) {
            case LCONST_0:
            case LCONST_1:
            case DCONST_0:
            case DCONST_1:
                size = 2;
                break;
            case LDC:
                Object value = ((LdcInsnNode) insn).cst;
                size = value instanceof Long || value instanceof Double ? 2 : 1;
                break;
            case GETSTATIC:
                size = Type.getType(((FieldInsnNode) insn).desc).getSize();
                break;
            default:
                size = 1;
                break;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue copyOperation(final AbstractInsnNode insn, final SourceValue value) {
        return new SourceValue(value.getSize(), insn);
    }

    @Override
    public SourceValue unaryOperation(final AbstractInsnNode insn, final SourceValue value) {
        int size;
        switch (insn.getOpcode()) {
            case LNEG:
            case DNEG:
            case I2L:
            case I2D:
            case L2D:
            case F2L:
            case F2D:
            case D2L:
                size = 2;
                break;
            case GETFIELD:
                size = Type.getType(((FieldInsnNode) insn).desc).getSize();
                break;
            default:
                size = 1;
                break;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue binaryOperation(
            final AbstractInsnNode insn, final SourceValue value1, final SourceValue value2) {
        int size;
        switch (insn.getOpcode()) {
            case LALOAD:
            case DALOAD:
            case LADD:
            case DADD:
            case LSUB:
            case DSUB:
            case LMUL:
            case DMUL:
            case LDIV:
            case DDIV:
            case LREM:
            case DREM:
            case LSHL:
            case LSHR:
            case LUSHR:
            case LAND:
            case LOR:
            case LXOR:
                size = 2;
                break;
            default:
                size = 1;
                break;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue ternaryOperation(
            final AbstractInsnNode insn,
            final SourceValue value1,
            final SourceValue value2,
            final SourceValue value3) {
        return new SourceValue(1, insn);
    }

    @Override
    public SourceValue naryOperation(
            final AbstractInsnNode insn, final List<? extends SourceValue> values) {
        int size;
        int opcode = insn.getOpcode();
        if (opcode == MULTIANEWARRAY) {
            size = 1;
        } else if (opcode == INVOKEDYNAMIC) {
            size = Type.getReturnType(((InvokeDynamicInsnNode) insn).desc).getSize();
        } else {
            size = Type.getReturnType(((MethodInsnNode) insn).desc).getSize();
        }
        return new SourceValue(size, insn);
    }

    @Override
    public void returnOperation(
            final AbstractInsnNode insn, final SourceValue value, final SourceValue expected) {
        // Nothing to do.
    }

    @Override
    public SourceValue merge(final SourceValue value1, final SourceValue value2) {
        if (value1.insns instanceof SmallSet && value2.insns instanceof SmallSet) {
            Set<AbstractInsnNode> setUnion =
                    ((SmallSet<AbstractInsnNode>) value1.insns)
                            .union((SmallSet<AbstractInsnNode>) value2.insns);
            if (setUnion == value1.insns && value1.size == value2.size) {
                return value1;
            } else {
                return new SourceValue(Math.min(value1.size, value2.size), setUnion);
            }
        }
        if (value1.size != value2.size || !containsAll(value1.insns, value2.insns)) {
            HashSet<AbstractInsnNode> setUnion = new HashSet<>();
            setUnion.addAll(value1.insns);
            setUnion.addAll(value2.insns);
            return new SourceValue(Math.min(value1.size, value2.size), setUnion);
        }
        return value1;
    }

    private static <E> boolean containsAll(final Set<E> self, final Set<E> other) {
        if (self.size() < other.size()) {
            return false;
        }
        return self.containsAll(other);
    }
}