org.jacoco.core.internal.instr.InterfaceFieldProbeArrayStrategy.java Source code

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Here is the source code for org.jacoco.core.internal.instr.InterfaceFieldProbeArrayStrategy.java

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/*******************************************************************************
 * Copyright (c) 2009, 2019 Mountainminds GmbH & Co. KG and Contributors
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *    Evgeny Mandrikov - initial API and implementation
 *
 *******************************************************************************/
package org.jacoco.core.internal.instr;

import org.jacoco.core.runtime.IExecutionDataAccessorGenerator;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * This strategy for Java 8 interfaces adds a static method requesting the probe
 * array from the runtime, a static field to hold the probe array and adds code
 * for its initialization into interface initialization method.
 */
class InterfaceFieldProbeArrayStrategy implements IProbeArrayStrategy {

    /**
     * Frame stack with a single boolean array.
     */
    private static final Object[] FRAME_STACK_ARRZ = new Object[] { InstrSupport.DATAFIELD_DESC };

    /**
     * Empty frame locals.
     */
    private static final Object[] FRAME_LOCALS_EMPTY = new Object[0];

    private final String className;
    private final long classId;
    private final int probeCount;
    private final IExecutionDataAccessorGenerator accessorGenerator;

    private boolean seenClinit = false;

    InterfaceFieldProbeArrayStrategy(final String className, final long classId, final int probeCount,
            final IExecutionDataAccessorGenerator accessorGenerator) {
        this.className = className;
        this.classId = classId;
        this.probeCount = probeCount;
        this.accessorGenerator = accessorGenerator;
    }

    public int storeInstance(final MethodVisitor mv, final boolean clinit, final int variable) {
        if (clinit) {
            final int maxStack = accessorGenerator.generateDataAccessor(classId, className, probeCount, mv);

            // Stack[0]: [Z

            mv.visitInsn(Opcodes.DUP);

            // Stack[1]: [Z
            // Stack[0]: [Z

            mv.visitFieldInsn(Opcodes.PUTSTATIC, className, InstrSupport.DATAFIELD_NAME,
                    InstrSupport.DATAFIELD_DESC);

            // Stack[0]: [Z

            mv.visitVarInsn(Opcodes.ASTORE, variable);

            seenClinit = true;
            return Math.max(maxStack, 2);
        } else {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, className, InstrSupport.INITMETHOD_NAME,
                    InstrSupport.INITMETHOD_DESC, true);
            mv.visitVarInsn(Opcodes.ASTORE, variable);
            return 1;
        }
    }

    public void addMembers(final ClassVisitor cv, final int probeCount) {
        createDataField(cv);
        createInitMethod(cv, probeCount);
        if (!seenClinit) {
            createClinitMethod(cv, probeCount);
        }
    }

    private void createDataField(final ClassVisitor cv) {
        cv.visitField(InstrSupport.DATAFIELD_INTF_ACC, InstrSupport.DATAFIELD_NAME, InstrSupport.DATAFIELD_DESC,
                null, null);
    }

    private void createInitMethod(final ClassVisitor cv, final int probeCount) {
        final MethodVisitor mv = cv.visitMethod(InstrSupport.INITMETHOD_ACC, InstrSupport.INITMETHOD_NAME,
                InstrSupport.INITMETHOD_DESC, null, null);
        mv.visitCode();

        // Load the value of the static data field:
        mv.visitFieldInsn(Opcodes.GETSTATIC, className, InstrSupport.DATAFIELD_NAME, InstrSupport.DATAFIELD_DESC);
        mv.visitInsn(Opcodes.DUP);

        // Stack[1]: [Z
        // Stack[0]: [Z

        // Skip initialization when we already have a data array:
        final Label alreadyInitialized = new Label();
        mv.visitJumpInsn(Opcodes.IFNONNULL, alreadyInitialized);

        // Stack[0]: [Z

        mv.visitInsn(Opcodes.POP);
        final int size = accessorGenerator.generateDataAccessor(classId, className, probeCount, mv);

        // Stack[0]: [Z

        // Return the class' probe array:
        mv.visitFrame(Opcodes.F_NEW, 0, FRAME_LOCALS_EMPTY, 1, FRAME_STACK_ARRZ);
        mv.visitLabel(alreadyInitialized);
        mv.visitInsn(Opcodes.ARETURN);

        mv.visitMaxs(Math.max(size, 2), 0); // Maximum local stack size is 2
        mv.visitEnd();
    }

    private void createClinitMethod(final ClassVisitor cv, final int probeCount) {
        final MethodVisitor mv = cv.visitMethod(InstrSupport.CLINIT_ACC, InstrSupport.CLINIT_NAME,
                InstrSupport.CLINIT_DESC, null, null);
        mv.visitCode();

        final int maxStack = accessorGenerator.generateDataAccessor(classId, className, probeCount, mv);

        // Stack[0]: [Z

        mv.visitFieldInsn(Opcodes.PUTSTATIC, className, InstrSupport.DATAFIELD_NAME, InstrSupport.DATAFIELD_DESC);

        mv.visitInsn(Opcodes.RETURN);

        mv.visitMaxs(maxStack, 0);
        mv.visitEnd();
    }

}