org.openjdk.jol.util
Class VMSupport

java.lang.Object
  org.openjdk.jol.util.VMSupport

public class VMSupport
extends Object

VM support doorway. Contains all the special tricks and methods to poll VM about it's secrets.

Author:

Aleksey Shipilev

Nested Class Summary

static class

VMSupport.SizeInfo

Field Summary

static int	ADDRESS_SIZE
static int	BOOLEAN_SIZE
static int	BYTE_SIZE
static int	CHAR_SIZE
static int	COMPRESSED_REF_SHIFT
static int	DOUBLE_SIZE
static int	FLOAT_SIZE
static int	INT_SIZE
static int	LONG_SIZE
static int	OBJ_ALIGNMENT
static int	OBJ_HEADER_SIZE
static int	REF_SIZE
static int	SHORT_SIZE
static sun.misc.Unsafe	U
static boolean	USE_COMPRESSED_REFS
static String	VM_NAME

Constructor Summary

VMSupport()

Method Summary

static long	addressOf(Object o)
static long	addressOf(Object o, int oopSize)
static int	align(int addr)
static int	align(int addr, int align)
static void	premain(String agentArgs, Instrumentation inst)
static String	safeToString(Object o) Produces the toString string, only calling toString() on known types, which do not mutate the instance.
static int	sizeOf(Object o)
static long	toNativeAddress(long address)
static VMSupport.SizeInfo	tryExactObjectSize(Object o, ClassLayout layout)
static String	vmDetails()

Methods inherited from class java.lang.Object

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

Field Detail

U

public static final sun.misc.Unsafe U

VM_NAME

public static final String VM_NAME

ADDRESS_SIZE

public static final int ADDRESS_SIZE

OBJ_ALIGNMENT

public static final int OBJ_ALIGNMENT

OBJ_HEADER_SIZE

public static final int OBJ_HEADER_SIZE

USE_COMPRESSED_REFS

public static final boolean USE_COMPRESSED_REFS

COMPRESSED_REF_SHIFT

public static final int COMPRESSED_REF_SHIFT

REF_SIZE

public static final int REF_SIZE

BOOLEAN_SIZE

public static final int BOOLEAN_SIZE

BYTE_SIZE

public static final int BYTE_SIZE

CHAR_SIZE

public static final int CHAR_SIZE

DOUBLE_SIZE

public static final int DOUBLE_SIZE

FLOAT_SIZE

public static final int FLOAT_SIZE

INT_SIZE

public static final int INT_SIZE

LONG_SIZE

public static final int LONG_SIZE

SHORT_SIZE

public static final int SHORT_SIZE

Constructor Detail

VMSupport

public VMSupport()

Method Detail

toNativeAddress

public static long toNativeAddress(long address)

align

public static int align(int addr)

align

public static int align(int addr,
                        int align)

vmDetails

public static String vmDetails()

addressOf

public static long addressOf(Object o)

addressOf

public static long addressOf(Object o,
                             int oopSize)

premain

public static void premain(String agentArgs,
                           Instrumentation inst)

tryExactObjectSize

public static VMSupport.SizeInfo tryExactObjectSize(Object o,
                                                    ClassLayout layout)

sizeOf

public static int sizeOf(Object o)

safeToString

public static String safeToString(Object o)

Produces the toString string, only calling toString() on known types, which do not mutate the instance.

Parameters:

o - object to process

Returns:

toString