jaspex.transactifier.FieldTransactifierClassVisitor.java Source code

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Here is the source code for jaspex.transactifier.FieldTransactifierClassVisitor.java

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/*
 * jaspex-mls: a Java Software Speculative Parallelization Framework
 * Copyright (C) 2015 Ivo Anjo <ivo.anjo@ist.utl.pt>
 *
 * This file is part of jaspex-mls.
 *
 * jaspex-mls is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * jaspex-mls 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with jaspex-mls.  If not, see <http://www.gnu.org/licenses/>.
 */

package jaspex.transactifier;

import jaspex.Options;
import jaspex.speculation.CommonTypes;

import org.objectweb.asm.*;
import static org.objectweb.asm.Opcodes.*;

import asmlib.Type;
import asmlib.*;

/** ClassVisitor que implementa a nova tctica de transactificao "unsafetrans", usando acesso
  * directo aos fields.
  **/
public class FieldTransactifierClassVisitor extends ClassVisitor {

    private boolean _injectStaticFieldBase = false;
    private boolean _injectClinit = true;
    private boolean _foundFields = false;
    private boolean _propagateOriginal = true;

    public FieldTransactifierClassVisitor(ClassVisitor cv) {
        super(Opcodes.ASM4, cv);
    }

    public FieldTransactifierClassVisitor(ClassVisitor cv, boolean propagateOriginal) {
        this(cv);
        _propagateOriginal = propagateOriginal;
    }

    @Override
    public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
        InfoField f = new InfoField(access, name, Type.fromBytecode(desc), null, value, null);

        if (!f.isFinal()) {
            _foundFields = true;

            // Criar field public static final long $offset_nomeoriginal,
            // que vai conter o offset do field na classe (usado pelo Unsafe)
            cv.visitField(ACC_PUBLIC | ACC_STATIC | ACC_FINAL | ACC_SYNTHETIC, "$offset_" + f.name(), "I", null,
                    null);

            // StaticFieldBase s  injectado se encontrarmos algum field static (no-final)
            if (f.isStatic())
                _injectStaticFieldBase = true;
        }

        // Propagar field original
        return _propagateOriginal ? cv.visitField(access, name, desc, signature, value) : null;
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        if (name.equals("<clinit>"))
            _injectClinit = false;
        return cv.visitMethod(access, name, desc, signature, exceptions);
    }

    @Override
    public void visitEnd() {
        if (_injectStaticFieldBase) {
            cv.visitField(ACC_PUBLIC | ACC_STATIC | ACC_FINAL | ACC_SYNTHETIC, "$staticFieldBase",
                    Options.STATICWORKAROUND ? CommonTypes.STATICFIELDBASE.bytecodeName()
                            : Type.OBJECT.bytecodeName(),
                    null, null);
        }

        // Adicionar <clinit> para classes que no o tinham j
        if (_injectClinit && _foundFields) {
            MethodVisitor mv = cv.visitMethod(ACC_STATIC, "<clinit>", "()V", null, null);
            mv.visitCode();
            mv.visitInsn(RETURN);
            mv.visitMaxs(0, 0);
            mv.visitEnd();
        }

        cv.visitEnd();
    }

}