Heap

java.lang.Object
- com.oracle.svm.core.heap.Heap

Direct Known Subclasses:: HeapImpl

public abstract class Heap
extends Object

Constructor Summary

Constructors
Modifier Constructor and Description

protected Heap()

Constructors
Modifier	Constructor and Description
`protected`	`Heap()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract void`	`attachThread(org.graalvm.nativeimage.IsolateThread isolateThread)` Notifies the heap that a new thread was attached to the VM.
`abstract org.graalvm.compiler.nodes.gc.BarrierSet`	`createBarrierSet(jdk.vm.ci.meta.MetaAccessProvider metaAccess)` Returns a suitable `BarrierSet` for the garbage collector that is used for this heap.
`abstract void`	`detachThread(org.graalvm.nativeimage.IsolateThread isolateThread)` Notifies the heap that a thread will be detached from the VM.
`abstract void`	`endSafepoint()` Reset the heap to the normal execution state.
`protected abstract List<Class<?>>`	`getAllClasses()` Get all known classes.
`abstract Reference<?>`	`getAndClearReferencePendingList()` Atomically get the list of pending references and clears (resets) it.
`abstract int`	`getClassCount()` Returns the number of classes in the heap (initialized as well as uninitialized).
`abstract GC`	`getGC()`
`static Heap`	`getHeap()`
`abstract int`	`getImageHeapNullRegionSize()` Returns the number of null bytes that should be prepended to the image heap during the image build.
`abstract int`	`getImageHeapOffsetInAddressSpace()` Returns an offset relative to the heap base, at which the image heap should be mapped into the address space.
`List<Class<?>>`	`getLoadedClasses()` Returns all loaded classes in the heap (see `PredefinedClassesSupport`).
`abstract ObjectHeader`	`getObjectHeader()` Get the ObjectHeader implementation that this Heap uses.
`abstract int`	`getPreferredAddressSpaceAlignment()` Returns a multiple to which the heap address space should be aligned to at runtime.
`abstract RuntimeCodeInfoGCSupport`	`getRuntimeCodeInfoGCSupport()`
`abstract boolean`	`hasReferencePendingList()` Determines if the heap currently has `Reference` objects that are pending to be enqueued.
`abstract boolean`	`isAllocationDisallowed()`
`abstract boolean`	`isInImageHeap(Object object)` Returns true if the given object is located in the image heap.
`abstract boolean`	`isInImageHeap(org.graalvm.word.Pointer objectPtr)` Returns true if the object at the given address is located in the image heap.
`abstract boolean`	`isInPrimaryImageHeap(Object object)` Whether the object is in the primary image heap, as opposed to an auxiliary image heap.
`abstract boolean`	`isInPrimaryImageHeap(org.graalvm.word.Pointer objectPtr)` Whether the object is in the primary image heap, as opposed to an auxiliary image heap.
`abstract void`	`optionValueChanged(RuntimeOptionKey<?> key)` Notify the GC that the value of a GC-relevant option changed.
`abstract void`	`prepareForSafepoint()` Prepare the heap for a safepoint.
`abstract boolean`	`printLocationInfo(Log log, org.graalvm.word.UnsignedWord value, boolean allowJavaHeapAccess, boolean allowUnsafeOperations)` If the passed value is within the Java heap, this method prints some information about that value and returns true.
`abstract void`	`resumeAllocation()`
`abstract void`	`suspendAllocation()`
`abstract boolean`	`tearDown()` Tear down the heap and free all allocated virtual memory chunks.
`abstract void`	`waitForReferencePendingList()` Blocks until the heap has pending references.
`abstract void`	`wakeUpReferencePendingListWaiters()` Unblocks any threads in `Heap.waitForReferencePendingList()`.
`abstract boolean`	`walkCollectedHeapObjects(ObjectVisitor visitor)` Walk all heap objects except the native image heap objects.
`abstract boolean`	`walkImageHeapObjects(ObjectVisitor visitor)` Walk all native image heap objects.
`abstract boolean`	`walkObjects(ObjectVisitor visitor)` Walk all the objects in the heap.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Heap
```
protected Heap()
```
- Method Detail
  - getHeap
```
public static Heap getHeap()
```
  - attachThread
```
public abstract void attachThread(org.graalvm.nativeimage.IsolateThread isolateThread)
```
    Notifies the heap that a new thread was attached to the VM. This allows to initialize heap-specific datastructures, e.g., the TLAB. This method is called for every thread except the main thread (i.e., the one that maps the image heap).
  - detachThread
```
public abstract void detachThread(org.graalvm.nativeimage.IsolateThread isolateThread)
```
    Notifies the heap that a thread will be detached from the VM. This allows to cleanup heap-specific resources, e.g., the TLAB. This method is called for every thread except the main thread (i.e., the one that maps the image heap).
  - suspendAllocation
```
public abstract void suspendAllocation()
```
  - resumeAllocation
```
public abstract void resumeAllocation()
```
  - isAllocationDisallowed
```
public abstract boolean isAllocationDisallowed()
```
  - getGC
```
public abstract GC getGC()
```
  - getRuntimeCodeInfoGCSupport
```
public abstract RuntimeCodeInfoGCSupport getRuntimeCodeInfoGCSupport()
```
  - walkObjects
```
public abstract boolean walkObjects(ObjectVisitor visitor)
```
    Walk all the objects in the heap. Must only be executed as part of a VM operation that causes a safepoint.
  - walkImageHeapObjects
```
public abstract boolean walkImageHeapObjects(ObjectVisitor visitor)
```
    Walk all native image heap objects. Must only be executed as part of a VM operation that causes a safepoint.
  - walkCollectedHeapObjects
```
public abstract boolean walkCollectedHeapObjects(ObjectVisitor visitor)
```
    Walk all heap objects except the native image heap objects. Must only be executed as part of a VM operation that causes a safepoint.
  - getClassCount
```
public abstract int getClassCount()
```
    Returns the number of classes in the heap (initialized as well as uninitialized).
  - getLoadedClasses
```
public List<Class<?>> getLoadedClasses()
```
    Returns all loaded classes in the heap (see PredefinedClassesSupport).
  - getAllClasses
```
protected abstract List<Class<?>> getAllClasses()
```
    Get all known classes. Intentionally protected to prevent access to classes that have not been "loaded" yet, see PredefinedClassesSupport.
  - getObjectHeader
```
public abstract ObjectHeader getObjectHeader()
```
    Get the ObjectHeader implementation that this Heap uses. TODO: This is used during native image generation to put appropriate headers on Objects in the native image heap. Is there any reason to expose the whole ObjectHeader interface, since only setBootImageOnLong(0L) is used then, to get the native image object header bits? TODO: Would an "Unsigned getBootImageObjectHeaderBits()" method be sufficient?
  - tearDown
```
public abstract boolean tearDown()
```
    Tear down the heap and free all allocated virtual memory chunks.
  - prepareForSafepoint
```
public abstract void prepareForSafepoint()
```
    Prepare the heap for a safepoint.
  - endSafepoint
```
public abstract void endSafepoint()
```
    Reset the heap to the normal execution state.
  - createBarrierSet
```
public abstract org.graalvm.compiler.nodes.gc.BarrierSet createBarrierSet(jdk.vm.ci.meta.MetaAccessProvider metaAccess)
```
    Returns a suitable BarrierSet for the garbage collector that is used for this heap.
  - getPreferredAddressSpaceAlignment
```
public abstract int getPreferredAddressSpaceAlignment()
```
    Returns a multiple to which the heap address space should be aligned to at runtime.
    
    See Also:
    
    CommittedMemoryProvider.guaranteesHeapPreferredAddressSpaceAlignment()
  - getImageHeapOffsetInAddressSpace
```
public abstract int getImageHeapOffsetInAddressSpace()
```
    Returns an offset relative to the heap base, at which the image heap should be mapped into the address space.
  - getImageHeapNullRegionSize
```
public abstract int getImageHeapNullRegionSize()
```
    Returns the number of null bytes that should be prepended to the image heap during the image build. This value must be a multiple of the page size. When the image heap is mapped at runtime, this extra memory gets mapped as well but is marked as inaccessible (see ImageHeapProvider for more details).
  - isInImageHeap
```
public abstract boolean isInImageHeap(Object object)
```
    Returns true if the given object is located in the image heap.
  - isInImageHeap
```
public abstract boolean isInImageHeap(org.graalvm.word.Pointer objectPtr)
```
    Returns true if the object at the given address is located in the image heap. Depending on the used GC, this method may only work reliably for pointers that point to the start of an object.
  - isInPrimaryImageHeap
```
public abstract boolean isInPrimaryImageHeap(Object object)
```
    Whether the object is in the primary image heap, as opposed to an auxiliary image heap.
  - isInPrimaryImageHeap
```
public abstract boolean isInPrimaryImageHeap(org.graalvm.word.Pointer objectPtr)
```
    Whether the object is in the primary image heap, as opposed to an auxiliary image heap.
  - hasReferencePendingList
```
public abstract boolean hasReferencePendingList()
```
    Determines if the heap currently has Reference objects that are pending to be enqueued.
  - waitForReferencePendingList
```
public abstract void waitForReferencePendingList()
                                          throws InterruptedException
```
    Blocks until the heap has pending references.
    
    Throws:
    
    InterruptedException
  - wakeUpReferencePendingListWaiters
```
public abstract void wakeUpReferencePendingListWaiters()
```
    Unblocks any threads in Heap.waitForReferencePendingList().
  - getAndClearReferencePendingList
```
public abstract Reference<?> getAndClearReferencePendingList()
```
    Atomically get the list of pending references and clears (resets) it. May return null.
  - printLocationInfo
```
public abstract boolean printLocationInfo(Log log,
                                          org.graalvm.word.UnsignedWord value,
                                          boolean allowJavaHeapAccess,
                                          boolean allowUnsafeOperations)
```
    If the passed value is within the Java heap, this method prints some information about that value and returns true. Otherwise, the method returns false.
  - optionValueChanged
```
public abstract void optionValueChanged(RuntimeOptionKey<?> key)
```
    Notify the GC that the value of a GC-relevant option changed.

Class Heap

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Heap

Method Detail

getHeap

attachThread

detachThread

suspendAllocation

resumeAllocation

isAllocationDisallowed

getGC

getRuntimeCodeInfoGCSupport

walkObjects

walkImageHeapObjects

walkCollectedHeapObjects

getClassCount

getLoadedClasses

getAllClasses

getObjectHeader

tearDown

prepareForSafepoint

endSafepoint

createBarrierSet

getPreferredAddressSpaceAlignment

getImageHeapOffsetInAddressSpace

getImageHeapNullRegionSize

isInImageHeap

isInImageHeap

isInPrimaryImageHeap

isInPrimaryImageHeap

hasReferencePendingList

waitForReferencePendingList

wakeUpReferencePendingListWaiters

getAndClearReferencePendingList

printLocationInfo

optionValueChanged