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 * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package jdk.jfr.internal.instrument;

import java.util.ArrayList;
import java.util.List;

import jdk.internal.org.objectweb.asm.Label;
import jdk.internal.org.objectweb.asm.MethodVisitor;
import jdk.internal.org.objectweb.asm.Opcodes;
import jdk.internal.org.objectweb.asm.commons.LocalVariablesSorter;
import jdk.internal.org.objectweb.asm.commons.Remapper;
import jdk.internal.org.objectweb.asm.commons.SimpleRemapper;
import jdk.internal.org.objectweb.asm.tree.MethodNode;
import jdk.jfr.internal.LogLevel;
import jdk.jfr.internal.LogTag;
import jdk.jfr.internal.Logger;

Class responsible for finding the call to inline and inlining it.
This code is heavily influenced by section 3.2.6 "Inline Method" in
"Using ASM framework to implement common bytecode transformation patterns",
E. Kuleshov, AOSD.07, March 2007, Vancouver, Canada.
http://asm.ow2.org/index.html
/**
 * Class responsible for finding the call to inline and inlining it.
 *
 * This code is heavily influenced by section 3.2.6 "Inline Method" in
 * "Using ASM framework to implement common bytecode transformation patterns",
 * E. Kuleshov, AOSD.07, March 2007, Vancouver, Canada.
 * http://asm.ow2.org/index.html
 */
@Deprecated
final class JIMethodCallInliner extends LocalVariablesSorter {

    private final String oldClass;
    private final String newClass;
    private final MethodNode inlineTarget;
    private final List<CatchBlock> blocks = new ArrayList<>();
    private boolean inlining;

    
inlineTarget defines the method to inline and also contains the actual
code to inline.
Params:
access – 
desc – 
mv – 
inlineTarget – 
oldClass – 
newClass – 
logger – /**
     * inlineTarget defines the method to inline and also contains the actual
     * code to inline.
     *
     * @param access
     * @param desc
     * @param mv
     * @param inlineTarget
     * @param oldClass
     * @param newClass
     * @param logger
     */
    public JIMethodCallInliner(int access, String desc, MethodVisitor mv,
            MethodNode inlineTarget, String oldClass, String newClass) {
        super(Opcodes.ASM7, access, desc, mv);
        this.oldClass = oldClass;
        this.newClass = newClass;
        this.inlineTarget = inlineTarget;

        if (Logger.shouldLog(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG)) {
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG,
                "MethodCallInliner: targetMethod=" + newClass + "."
                + inlineTarget.name + inlineTarget.desc);
        }
    }

    @Override
    public void visitMethodInsn(int opcode, String owner, String name,
            String desc, boolean itf) {
        // Now we are looking at method call in the source method
        if (!shouldBeInlined(owner, name, desc)) {
            // If this method call should not be inlined, just keep it
            mv.visitMethodInsn(opcode, owner, name, desc, itf);
            return;
        }
        // If the call should be inlined, we create a MethodInliningAdapter
        // The MIA will walk the instructions in the inlineTarget and add them
        // to the current method, doing the necessary name remappings.
        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inlining call to " + name + desc);
        Remapper remapper = new SimpleRemapper(oldClass, newClass);
        Label end = new Label();
        inlining = true;
        inlineTarget.instructions.resetLabels();
        JIMethodInliningAdapter mia = new JIMethodInliningAdapter(this, end,
                opcode == Opcodes.INVOKESTATIC ? Opcodes.ACC_STATIC : 0, desc,
                remapper);
        inlineTarget.accept(mia);
        inlining = false;
        super.visitLabel(end);
    }

    
Determine if the method should be inlined or not.
/**
     * Determine if the method should be inlined or not.
     */
    private boolean shouldBeInlined(String owner, String name, String desc) {
        return inlineTarget.desc.equals(desc) && inlineTarget.name.equals(name)
                && owner.equals(newClass.replace('.', '/'));
    }

    @Override
    public void visitTryCatchBlock(Label start, Label end, Label handler,
            String type) {
        if (!inlining) {
            // try-catch blocks are saved here and replayed at the end
            // of the method (in visitMaxs)
            blocks.add(new CatchBlock(start, end, handler, type));
        } else {
            super.visitTryCatchBlock(start, end, handler, type);
        }
    }

    @Override
    public void visitMaxs(int stack, int locals) {
        for (CatchBlock b : blocks) {
            super.visitTryCatchBlock(b.start, b.end, b.handler, b.type);
        }
        super.visitMaxs(stack, locals);
    }

    static final class CatchBlock {

        final Label start;
        final Label end;
        final Label handler;
        final String type;

        CatchBlock(Label start, Label end, Label handler, String type) {
            this.start = start;
            this.end = end;
            this.handler = handler;
            this.type = type;
        }
    }
}