com.oracle.svm.core.config

Class ObjectLayout

java.lang.Object

com.oracle.svm.core.config.ObjectLayout

public class ObjectLayout
extends Object

Defines the layout of objects. The layout of instance objects is:

• hub (reference)
• instance fields (references, primitives)
• optional: hashcode (int)

The hashcode is appended after instance fields and is only present if the identity hashcode is used for that type. The layout of array objects is:

• hub (reference)
• array length (int)
• hashcode (int)
• array elements (length * reference or primitive)

The hashcode is always present in arrays. Note that on 64-bit targets it does not impose any size overhead for arrays with 64-bit aligned elements (e.g. arrays of objects).

Constructor Summary

Constructors

Constructor and Description
ObjectLayout(SubstrateTargetDescription target)
ObjectLayout(SubstrateTargetDescription target, int hubOffset)

Method Summary

Modifier and Type	Method and Description
int	alignUp(int obj) Align the specified offset or address up to ObjectLayout.getAlignment().
long	alignUp(long obj) Align the specified offset or address up to ObjectLayout.getAlignment().
int	getAlignment() The minimum alignment of objects (instances and arrays).
int	getArrayBaseOffset(jdk.vm.ci.meta.JavaKind kind)
long	getArrayElementOffset(jdk.vm.ci.meta.JavaKind kind, int index)
int	getArrayHashCodeOffset()
int	getArrayIndexScale(jdk.vm.ci.meta.JavaKind kind)
int	getArrayIndexShift(jdk.vm.ci.meta.JavaKind kind)
int	getArrayLengthOffset()
long	getArraySize(jdk.vm.ci.meta.JavaKind kind, int length)
static jdk.vm.ci.meta.JavaKind	getCallSignatureKind(boolean isEntryPoint, jdk.vm.ci.meta.ResolvedJavaType type, jdk.vm.ci.meta.MetaAccessProvider metaAccess, jdk.vm.ci.code.TargetDescription target)
int	getDeoptScratchSpace() Returns the amount of scratch space which must be reserved for return value registers in DeoptimizedFrame.
int	getFirstFieldOffset()
int	getHubNextOffset()
int	getHubOffset()
int	getReferenceSize()
boolean	isAligned(long value) Tests if the given offset or address is aligned according to ObjectLayout.getAlignment().
int	sizeInBytes(jdk.vm.ci.meta.JavaKind kind) The size (in bytes) of values with the given kind.

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectLayout

public ObjectLayout(SubstrateTargetDescription target)

ObjectLayout

public ObjectLayout(SubstrateTargetDescription target,
                    int hubOffset)

Method Detail

getAlignment

public int getAlignment()

The minimum alignment of objects (instances and arrays).

isAligned

public boolean isAligned(long value)

Tests if the given offset or address is aligned according to ObjectLayout.getAlignment().

getReferenceSize

public int getReferenceSize()

getDeoptScratchSpace

public int getDeoptScratchSpace()

Returns the amount of scratch space which must be reserved for return value registers in DeoptimizedFrame.

sizeInBytes

public int sizeInBytes(jdk.vm.ci.meta.JavaKind kind)

The size (in bytes) of values with the given kind.

getArrayIndexShift

public int getArrayIndexShift(jdk.vm.ci.meta.JavaKind kind)

getArrayIndexScale

public int getArrayIndexScale(jdk.vm.ci.meta.JavaKind kind)

alignUp

public int alignUp(int obj)

Align the specified offset or address up to ObjectLayout.getAlignment().

alignUp

public long alignUp(long obj)

Align the specified offset or address up to ObjectLayout.getAlignment().

getHubOffset

public int getHubOffset()

getHubNextOffset

public int getHubNextOffset()

getFirstFieldOffset

public int getFirstFieldOffset()

getArrayLengthOffset

public int getArrayLengthOffset()

getArrayHashCodeOffset

public int getArrayHashCodeOffset()

getArrayBaseOffset

public int getArrayBaseOffset(jdk.vm.ci.meta.JavaKind kind)

getArrayElementOffset

public long getArrayElementOffset(jdk.vm.ci.meta.JavaKind kind,
                                  int index)

getArraySize

public long getArraySize(jdk.vm.ci.meta.JavaKind kind,
                         int length)

getCallSignatureKind

public static jdk.vm.ci.meta.JavaKind getCallSignatureKind(boolean isEntryPoint,
                                                           jdk.vm.ci.meta.ResolvedJavaType type,
                                                           jdk.vm.ci.meta.MetaAccessProvider metaAccess,
                                                           jdk.vm.ci.code.TargetDescription target)