com.oracle.svm.core.genscavenge

Class Generation

java.lang.Object

com.oracle.svm.core.genscavenge.Generation

Direct Known Subclasses:

OldGeneration, YoungGeneration

public abstract class Generation
extends Object

A Generation is a collection of one or more Spaces.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	name Final state.

Method Summary

Modifier and Type	Method and Description
String	getName() The name of this generation.
protected abstract boolean	isValidSpace(Space space) Returns true if the space is a valid Space in this generation, else false.
protected abstract Object	promoteObject(Object original, org.graalvm.word.Pointer objRef, int innerOffset, boolean compressed) Promote an Object to this Generation, either by HeapChunk motion or copying.
abstract Log	report(Log log, boolean traceHeapChunks) Report some statistics about the Generation to a Log.
protected abstract boolean	verify(HeapVerifier.Occasion occasion)
abstract boolean	walkObjects(ObjectVisitor visitor) Walk the Objects in this Space, passing each to a Visitor.

Methods inherited from class java.lang.Object

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

Field Detail

name

protected final String name

Final state.

Method Detail

walkObjects

public abstract boolean walkObjects(ObjectVisitor visitor)

Walk the Objects in this Space, passing each to a Visitor.

Parameters:

visitor - An ObjectVisitor.

Returns:

True if all visits returned true, false otherwise.

getName

public String getName()

The name of this generation.

report

public abstract Log report(Log log,
                           boolean traceHeapChunks)

Report some statistics about the Generation to a Log.

promoteObject

protected abstract Object promoteObject(Object original,
                                        org.graalvm.word.Pointer objRef,
                                        int innerOffset,
                                        boolean compressed)

Promote an Object to this Generation, either by HeapChunk motion or copying. If the original is copied, a forwarding pointer to the new Object is left in place of the original Object. This turns an Object from white to grey: the object is in this Generation, but has not yet had its interior pointers visited.

Parameters:

original - The original Object to be promoted.

objRef - The address of the reference to the original object.

innerOffset - The byte offset of a derived pointer from head of the original object. Subtract to get to the head of the original object, add to get back to a derived pointer inside the original object.

compressed - Whether object references are compressed.

Returns:

The promoted Object, either the original if promotion was done by HeapChunk motion, or a new Object if promotion was done by copying. For debugging GR-9912:

isValidSpace

protected abstract boolean isValidSpace(Space space)

Returns true if the space is a valid Space in this generation, else false.

verify

protected abstract boolean verify(HeapVerifier.Occasion occasion)