org.mmtk.vm

Class TraceInterface

java.lang.Object

org.mmtk.vm.TraceInterface

Direct Known Subclasses:

TraceInterface

public abstract class TraceInterface
extends Object

Class that supports scanning Objects or Arrays for references during tracing, handling those references, and computing death times

Constructor Summary

Constructors

Constructor and Description
TraceInterface()

Method Summary

Modifier and Type	Method and Description
abstract Offset	adjustSlotOffset(boolean isScalar, ObjectReference src, Address slot) This adjusts the offset into an object to reflect what it would look like if the fields were laid out in memory space immediately after the object pointer.
abstract boolean	gcEnabled() Returns true if the VM is ready for a garbage collection.
abstract Address	getBootImageLink()
abstract Word	getDeathTime(ObjectReference ref)
abstract int	getHeaderEndOffset()
abstract int	getHeaderSize()
abstract ObjectReference	getLink(ObjectReference ref)
abstract Word	getOID()
abstract Word	getOID(ObjectReference ref)
abstract void	setDeathTime(ObjectReference ref, Word time_)
abstract void	setLink(ObjectReference ref, ObjectReference link)
abstract void	setOID(Word oid)
abstract Address	skipOwnFramesAndDump(ObjectReference typeRef) This skips over the frames added by the tracing algorithm, outputs information identifying the method the containts the "new" call triggering the allocation, and returns the address of the first non-trace, non-alloc stack frame.
abstract void	updateDeathTime(ObjectReference obj) Update an object's death time.
abstract void	updateTime(Word time_)

Methods inherited from class java.lang.Object

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

Constructor Detail

TraceInterface

public TraceInterface()

Method Detail

gcEnabled

public abstract boolean gcEnabled()

Returns true if the VM is ready for a garbage collection.

Returns:

true if the VM is ready for GC, false otherwise.

adjustSlotOffset

public abstract Offset adjustSlotOffset(boolean isScalar,
                                        ObjectReference src,
                                        Address slot)

This adjusts the offset into an object to reflect what it would look like if the fields were laid out in memory space immediately after the object pointer.

Parameters:

isScalar - If this is a pointer store to a scalar object

src - The address of the source object

slot - The address within src into which the update will be stored

Returns:

The easy to understand offset of the slot

skipOwnFramesAndDump

public abstract Address skipOwnFramesAndDump(ObjectReference typeRef)

This skips over the frames added by the tracing algorithm, outputs information identifying the method the containts the "new" call triggering the allocation, and returns the address of the first non-trace, non-alloc stack frame.

Parameters:

typeRef - The type reference (tib) of the object just allocated

Returns:

The frame pointer address for the method that allocated the object

updateDeathTime

public abstract void updateDeathTime(ObjectReference obj)

Update an object's death time.

Parameters:

obj - the object

setDeathTime

public abstract void setDeathTime(ObjectReference ref,
                                  Word time_)

setLink

public abstract void setLink(ObjectReference ref,
                             ObjectReference link)

updateTime

public abstract void updateTime(Word time_)

getOID

public abstract Word getOID(ObjectReference ref)

getDeathTime

public abstract Word getDeathTime(ObjectReference ref)

getLink

public abstract ObjectReference getLink(ObjectReference ref)

getBootImageLink

public abstract Address getBootImageLink()

getOID

public abstract Word getOID()

setOID

public abstract void setOID(Word oid)

getHeaderSize

public abstract int getHeaderSize()

getHeaderEndOffset

public abstract int getHeaderEndOffset()