joeq.Allocator
Class ObjectLayout

java.lang.Object
  joeq.Allocator.ObjectLayout

public abstract class ObjectLayout
extends Object

This interface contains constants that define the joeq object layout. You can play with these constants to experiment with different object layouts.

Version:

$Id: ObjectLayout.java 1449 2004-03-09 04:04:18Z jwhaley $

Author:

John Whaley

Field Summary

static int	ARRAY_ELEMENT_OFFSET Offset of array element 0, in bytes.
static int	ARRAY_HEADER_SIZE Size of array header, in bytes.
static int	ARRAY_LENGTH_OFFSET Offset of array length word, in bytes.
static int	GC_BIT Bit in object header for use by GC.
static int	HASHED Object has been hashed.
static int	HASHED_MOVED Object has been hashed and later moved.
static int	LOCK_COUNT_INC Value to add to status word to increment lock count by one.
static int	LOCK_COUNT_MASK Mask of the lock count in the status word.
static int	LOCK_COUNT_SHIFT Bit location of lock count in the status word.
static int	LOCK_EXPANDED Lock has been expanded.
static int	OBJ_HEADER_SIZE Size of (non-array) object header, in bytes.
static int	STATUS_FLAGS_MASK Mask for status flags.
static int	STATUS_WORD_OFFSET Offset of status word, in bytes.
static int	THREAD_ID_MASK Mask of the thread id in the status word.
static int	THREAD_ID_SHIFT Bit location of thread id in the status word.
static int	VTABLE_OFFSET Offset of vtable, in bytes.

Constructor Summary

ObjectLayout()

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ARRAY_LENGTH_OFFSET

public static final int ARRAY_LENGTH_OFFSET

Offset of array length word, in bytes.

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Constant Field Values

STATUS_WORD_OFFSET

public static final int STATUS_WORD_OFFSET

Offset of status word, in bytes.

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Constant Field Values

VTABLE_OFFSET

public static final int VTABLE_OFFSET

Offset of vtable, in bytes.

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Constant Field Values

ARRAY_ELEMENT_OFFSET

public static final int ARRAY_ELEMENT_OFFSET

Offset of array element 0, in bytes.

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Constant Field Values

OBJ_HEADER_SIZE

public static final int OBJ_HEADER_SIZE

Size of (non-array) object header, in bytes.

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Constant Field Values

ARRAY_HEADER_SIZE

public static final int ARRAY_HEADER_SIZE

Size of array header, in bytes.

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Constant Field Values

HASHED

public static final int HASHED

Object has been hashed. If it moves, we need to store the old address.

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Constant Field Values

HASHED_MOVED

public static final int HASHED_MOVED

Object has been hashed and later moved. The hash code is stored just past the object.

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Constant Field Values

GC_BIT

public static final int GC_BIT

Bit in object header for use by GC.

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Constant Field Values

STATUS_FLAGS_MASK

public static final int STATUS_FLAGS_MASK

Mask for status flags.

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Constant Field Values

THREAD_ID_SHIFT

public static final int THREAD_ID_SHIFT

Bit location of thread id in the status word.

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Constant Field Values

THREAD_ID_MASK

public static final int THREAD_ID_MASK

Mask of the thread id in the status word.

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Constant Field Values

LOCK_COUNT_MASK

public static final int LOCK_COUNT_MASK

Mask of the lock count in the status word.

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Constant Field Values

LOCK_COUNT_INC

public static final int LOCK_COUNT_INC

Value to add to status word to increment lock count by one.

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Constant Field Values

LOCK_COUNT_SHIFT

public static final int LOCK_COUNT_SHIFT

Bit location of lock count in the status word.

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Constant Field Values

LOCK_EXPANDED

public static final int LOCK_EXPANDED

Lock has been expanded. Masking out this value and the status flags mask gives the address of the expanded lock structure.

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Constant Field Values

Constructor Detail

ObjectLayout

public ObjectLayout()