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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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 * The above copyright notice and either this complete permission notice or at a
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package com.oracle.truffle.api.frame;

import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;


A slot in a Frame and FrameDescriptor that can store a value of a given type. 
Since:0.8 or earlier
/**
 * A slot in a {@link Frame} and {@link FrameDescriptor} that can store a value of a given type.
 *
 * @since 0.8 or earlier
 */
public final class FrameSlot implements Cloneable {

    final FrameDescriptor descriptor;
    private final Object identifier;
    private final Object info;
    final int index;
    /*
     * The FrameSlot cannot be made immutable by moving the kind field to FrameDescriptor, because
     * it would force getFrameSlotKind and setFrameSlotKind to check frameSlot removal which would
     * require locking the FrameDescriptor, instead of current simple read from the volatile kind
     * field.
     */
    @CompilationFinal volatile FrameSlotKind kind;

    FrameSlot(FrameDescriptor descriptor, Object identifier, Object info, FrameSlotKind kind, int index) {
        this.descriptor = descriptor;
        this.identifier = identifier;
        this.info = info;
        this.index = index;
        this.kind = kind;
    }

    
Identifier of the slot.

Returns:value as specified in FrameDescriptor.addFrameSlot(Object) parameter
Since:0.8 or earlier
/**
     * Identifier of the slot.
     *
     * @return value as specified in {@link FrameDescriptor#addFrameSlot(java.lang.Object)}
     *         parameter
     * @since 0.8 or earlier
     */
    public Object getIdentifier() {
        return identifier;
    }

    
Information about the slot.

Returns:value as specified as second parameter of FrameDescriptor.addFrameSlot(Object, Object, FrameSlotKind)
Since:0.8 or earlier
/**
     * Information about the slot.
     *
     * @return value as specified as second parameter of
     *         {@link FrameDescriptor#addFrameSlot(java.lang.Object, java.lang.Object, com.oracle.truffle.api.frame.FrameSlotKind)}
     * @since 0.8 or earlier
     */
    public Object getInfo() {
        return info;
    }

    
Index of the slot in the FrameDescriptor. 
Returns:position of the slot computed after 
        adding it.
Since:0.8 or earlier
Deprecated:in 1.0 without replacement
/**
     * Index of the slot in the {@link FrameDescriptor}.
     *
     * @return position of the slot computed after
     *         {@link FrameDescriptor#addFrameSlot(java.lang.Object, java.lang.Object, com.oracle.truffle.api.frame.FrameSlotKind)
     *         adding} it.
     * @since 0.8 or earlier
     * @deprecated in 1.0 without replacement
     */
    @Deprecated
    public int getIndex() {
        return index;
    }

    
Kind of the slot. Specified either at 
creation time or updated via FrameDescriptor.setFrameSlotKind(FrameSlot, FrameSlotKind) method. 
Returns:current kind of this slot
Since:0.8 or earlier
Deprecated:in 1.0 use FrameDescriptor.getFrameSlotKind(FrameSlot) instead.
/**
     * Kind of the slot. Specified either at
     * {@link FrameDescriptor#addFrameSlot(java.lang.Object, com.oracle.truffle.api.frame.FrameSlotKind)
     * creation time} or updated via
     * {@link FrameDescriptor#setFrameSlotKind(FrameSlot, FrameSlotKind)} method.
     *
     * @return current kind of this slot
     * @since 0.8 or earlier
     * @deprecated in 1.0 use {@link FrameDescriptor#getFrameSlotKind(FrameSlot)} instead.
     */
    @Deprecated
    public FrameSlotKind getKind() {
        return descriptor.getFrameSlotKind(this);
    }

    
Changes the kind of this slot. Change of the slot kind is done on slow path and invalidates assumptions about version of the descriptor it belongs to. 
Params:
  • kind – new kind of the slot
Since:0.8 or earlier
Deprecated:in 1.0 use FrameDescriptor.setFrameSlotKind(FrameSlot, FrameSlotKind) instead.
/**
     * Changes the kind of this slot. Change of the slot kind is done on <em>slow path</em> and
     * invalidates assumptions about version of the {@link FrameDescriptor descriptor} it belongs
     * to.
     *
     * @param kind new kind of the slot
     * @since 0.8 or earlier
     * @deprecated in 1.0 use {@link FrameDescriptor#setFrameSlotKind(FrameSlot, FrameSlotKind)}
     *             instead.
     */
    @Deprecated
    public void setKind(final FrameSlotKind kind) {
        descriptor.setFrameSlotKind(this, kind);
    }

    
Since:0.8 or earlier
/** @since 0.8 or earlier */
    @Override
    public String toString() {
        CompilerAsserts.neverPartOfCompilation("do not call FrameSlot.toString from compiled code");
        return "[" + index + "," + identifier + "," + kind + "]";
    }
}