src/java.base/share/classes/java/lang/classfile/attribute/CodeAttribute.java

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package java.lang.classfile.attribute;

import java.lang.classfile.*;
import java.lang.classfile.AttributeMapper.AttributeStability;

import jdk.internal.classfile.impl.BoundAttribute;

/**
 * Models the {@link Attributes#code() Code} attribute (JVMS {@jvms 4.7.3}),
 * which contains the bytecode of this method.
 * <p>
 * This attribute only appears on methods, and does not permit {@linkplain
 * AttributeMapper#allowMultiple multiple instances} in a method.  It has a
 * data dependency on the {@linkplain AttributeStability#CP_REFS constant pool}.
 * <p>
 * This attribute was introduced in the Java Platform version 1.0.2, major
 * version {@value ClassFile#JAVA_1_VERSION}.
 *
 * @apiNote
 * {@code CodeAttribute} models properties of a {@code Code} attribute read
 * from {@code class} files.  General {@code class} file transformation should
 * process and traverse a {@link CodeModel} in the traversal of a {@link
 * MethodModel}, to support transformation of {@code Code} attributes currently
 * being built.
 *
 * @see Attributes#code()
 * @see CodeModel
 * @jvms 4.7.3 The {@code Code} Attribute
 * @since 24
 */
public sealed interface CodeAttribute extends Attribute<CodeAttribute>, CodeModel
        permits BoundAttribute.BoundCodeAttribute {

    /**
     * {@return the maximum size of the local variable table}
     */
    int maxLocals();

    /**
     * {@return the maximum size of the operand stack}
     */
    int maxStack();

    /**
     * {@return The length of the code array in bytes}
     */
    int codeLength();

    /**
     * {@return the bytes (bytecode) of the code array}
     */
    byte[] codeArray();

    /**
     * {@return the position of the {@code label} in the {@link #codeArray codeArray}}
     * The label represents a cursor pointing at immediately before the returned
     * index into the {@code code} array.
     *
     * @param label a marker for a position within this {@code CodeAttribute}
     * @throws IllegalArgumentException if the {@code label} is not from this attribute
     */
    int labelToBci(Label label);
}