gov.nasa.jpf.vm

Class PSIMHeap

java.lang.Object

gov.nasa.jpf.vm.GenericHeap

gov.nasa.jpf.vm.GenericSGOIDHeap

gov.nasa.jpf.vm.PSIMHeap

All Implemented Interfaces:

Heap, java.lang.Iterable<ElementInfo>

public class PSIMHeap
extends GenericSGOIDHeap

heap implementation that uses a PersistentStagingMsbIntMap as the underlying container This is intended for large state spaces, to minimize store/restore costs. While those are negligible for PersistentMaps, the per-change overhead is not since the container has to duplicate the access path to the changed node on every modification. Efficiency of PSIMHeap therefore relies on accessing objects in a consecutive pattern, i.e. depends on clustered access. <2do> this should not be a GenericSGOIDHeap derived class since this includes a number of non-persistent data structures (allocCounts, intern strings, pinDowns) that are not persistent, i.e. still requires a memento that creates/restores snapshots of these and hence looses a lot of the benefit we use a persistent map for NOTE - a reference value of 0 represents null and therefore is not a valid SGOID

Nested Class Summary

Nested classes/interfaces inherited from class gov.nasa.jpf.vm.GenericHeap

GenericHeap.ElementInfoMarker

Field Summary

Fields inherited from class gov.nasa.jpf.vm.GenericSGOIDHeap

allocCounts, nextSgoid, sgoids

Fields inherited from class gov.nasa.jpf.vm.GenericHeap

attributes, elementInfoMarker, internStringsMap, liveBitValue, markQueue, nLiveObjects, pinDownList, vm, weakRefs

Constructor Summary

Constructors

Constructor and Description
PSIMHeap(Config config, KernelState ks)

Method Summary

Modifier and Type	Method and Description
ElementInfo	get(int ref) public getter to access but not change ElementInfos
Memento<Heap>	getMemento()
Memento<Heap>	getMemento(MementoFactory factory)
ElementInfo	getModifiable(int ref) public getter to access modifiable ElementInfos;
java.util.Iterator<ElementInfo>	iterator() return Iterator for all non-null ElementInfo entries
java.lang.Iterable<ElementInfo>	liveObjects()
protected void	remove(int ref) internal remover used by generic sweep
void	resetVolatiles()
void	restoreVolatiles()
protected void	set(int index, ElementInfo ei) internal setter used during allocation
int	size()
protected void	sweep() this implementation uses a generic ElementInfo iterator, it can be replaced with a more efficient container specific version

Methods inherited from class gov.nasa.jpf.vm.GenericSGOIDHeap

getNewElementInfoIndex, getSUTAllocationContext, getSystemAllocationContext, initAllocationContext

Methods inherited from class gov.nasa.jpf.vm.GenericHeap

addToInternStrings, addToPinDownList, checkConsistency, cleanUpDanglingReferences, cleanupWeakRefs, createArray, createElementInfo, createObject, gc, getArrayClassInfo, hasChanged, initializeStringObject, isAlive, isGcEnabled, isOutOfMemory, mark, markChanged, markFinalizableObjects, markStaticRoot, markThreadRoot, newArray, newInternString, newObject, newString, newString, newSystemArray, newSystemObject, newSystemString, newSystemThrowable, queueMark, registerPinDown, registerWeakReference, releasePinDown, removeFromPinDownList, setGcEnabled, setOutOfMemory, setStored, unmarkAll

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

PSIMHeap

public PSIMHeap(Config config,
                KernelState ks)

Method Detail

size

public int size()

set

protected void set(int index,
                   ElementInfo ei)

Description copied from class: GenericHeap

internal setter used during allocation

Specified by:

set in class GenericHeap

get

public ElementInfo get(int ref)

Description copied from class: GenericHeap

public getter to access but not change ElementInfos

Specified by:

get in interface Heap

Specified by:

get in class GenericHeap

getModifiable

public ElementInfo getModifiable(int ref)

Description copied from class: GenericHeap

public getter to access modifiable ElementInfos;

Specified by:

getModifiable in interface Heap

Specified by:

getModifiable in class GenericHeap

remove

protected void remove(int ref)

Description copied from class: GenericHeap

internal remover used by generic sweep

Specified by:

remove in class GenericHeap

sweep

protected void sweep()

Description copied from class: GenericHeap

this implementation uses a generic ElementInfo iterator, it can be replaced with a more efficient container specific version

Overrides:

sweep in class GenericHeap

iterator

public java.util.Iterator<ElementInfo> iterator()

Description copied from class: GenericHeap

return Iterator for all non-null ElementInfo entries

Specified by:

iterator in interface java.lang.Iterable<ElementInfo>

Specified by:

iterator in class GenericHeap

liveObjects

public java.lang.Iterable<ElementInfo> liveObjects()

Specified by:

liveObjects in interface Heap

Specified by:

liveObjects in class GenericHeap

resetVolatiles

public void resetVolatiles()

Specified by:

resetVolatiles in interface Heap

Specified by:

resetVolatiles in class GenericHeap

restoreVolatiles

public void restoreVolatiles()

Specified by:

restoreVolatiles in interface Heap

Specified by:

restoreVolatiles in class GenericHeap

getMemento

public Memento<Heap> getMemento(MementoFactory factory)

Specified by:

getMemento in interface Heap

Specified by:

getMemento in class GenericHeap

getMemento

public Memento<Heap> getMemento()

Specified by:

getMemento in interface Heap

Specified by:

getMemento in class GenericHeap