ObjectModel (Jikes RVM API)

java.lang.Object
- org.mmtk.vm.ObjectModel

Direct Known Subclasses:: ObjectModel

public abstract class ObjectModel
extends Object

Constructor Summary

Constructors
Constructor and Description

ObjectModel()

Constructors
Constructor and Description
`ObjectModel()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) static Offset`	`arrayBaseOffsetTrapdoor(ObjectModel o)`
`abstract boolean`	`attemptAvailableBits(ObjectReference object, Word oldVal, Word newVal)` Attempts to set the bits available for memory manager use in an object.
`abstract ObjectReference`	`copy(ObjectReference from, int allocator)` Copy an object using a plan's allocCopy to get space and install the forwarding pointer.
`abstract Address`	`copyTo(ObjectReference from, ObjectReference to, Address region)` Copy an object to be pointer to by the to address.
`abstract void`	`dumpObject(ObjectReference object)` Dump debugging information for an object.
`abstract Offset`	`GC_HEADER_OFFSET()` Gets the offset of the memory management header from the object reference address.
`abstract int`	`getAlignOffsetWhenCopied(ObjectReference object)` Return the alignment offset requirements for a copy of this object
`abstract int`	`getAlignWhenCopied(ObjectReference object)` Return the alignment requirement for a copy of this object
`protected abstract Offset`	`getArrayBaseOffset()`
`abstract int`	`getArrayLength(ObjectReference object)` Get the length of an array object.
`abstract int`	`getCurrentSize(ObjectReference object)` Return the size used by an object
`abstract ObjectReference`	`getNextObject(ObjectReference object)`
`abstract Address`	`getObjectEndAddress(ObjectReference object)` Gets a pointer to the address just past the end of the object.
`abstract ObjectReference`	`getObjectFromStartAddress(Address start)`
`abstract ObjectReference`	`getReferenceWhenCopiedTo(ObjectReference from, Address to)` Return the reference that an object will be referred to after it is copied to the specified region.
`abstract int`	`getSizeWhenCopied(ObjectReference object)` Return the size required to copy an object
`abstract byte[]`	`getTypeDescriptor(ObjectReference ref)` Get the type descriptor for an object.
`abstract boolean`	`isAcyclic(ObjectReference typeRef)` Checks if a reference of the given type in another object is inherently acyclic.
`abstract boolean`	`isArray(ObjectReference object)`
`abstract boolean`	`isPrimitiveArray(ObjectReference object)`
`abstract Address`	`objectStartRef(ObjectReference object)` Returns the lowest address of the storage associated with an object.
`abstract Word`	`prepareAvailableBits(ObjectReference object)` Gets the value of bits available for memory manager use in an object, in preparation for setting those bits.
`abstract Word`	`readAvailableBitsWord(ObjectReference object)` Read the bits available for memory manager use in an object.
`abstract byte`	`readAvailableByte(ObjectReference object)` Read the byte available for memory manager use in an object.
`abstract Address`	`refToAddress(ObjectReference object)` Returns an address guaranteed to be inside the storage assocatied with and object.
`abstract void`	`writeAvailableBitsWord(ObjectReference object, Word val)` Sets the bits available for memory manager use in an object.
`abstract void`	`writeAvailableByte(ObjectReference object, byte val)` Sets the byte available for memory manager use in an object.

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

- Constructor Detail
  - ObjectModel
```
public ObjectModel()
```
- Method Detail
  - copy
```
public abstract ObjectReference copy(ObjectReference from,
                                     int allocator)
```
    Copy an object using a plan's allocCopy to get space and install the forwarding pointer. On entry, from must have been reserved for copying by the caller. This method calls the plan's getStatusForCopy() method to establish a new status word for the copied object and postCopy() to allow the plan to perform any post copy actions.
    
    Parameters:
    
    from - the address of the object to be copied
    
    allocator - The allocator to use.
    
    Returns:
    
    the address of the new object
  - copyTo
```
public abstract Address copyTo(ObjectReference from,
                               ObjectReference to,
                               Address region)
```
    Copy an object to be pointer to by the to address. This is required for delayed-copy collectors such as compacting collectors. During the collection, MMTk reserves a region in the heap for an object as per requirements found from ObjectModel and then asks ObjectModel to determine what the object's reference will be post-copy.
    
    Parameters:
    
    from - the address of the object to be copied
    
    to - The target location.
    
    region - The start of the region that was reserved for this object
    
    Returns:
    
    Address The address past the end of the copied object
  - getReferenceWhenCopiedTo
```
public abstract ObjectReference getReferenceWhenCopiedTo(ObjectReference from,
                                                         Address to)
```
    Return the reference that an object will be referred to after it is copied to the specified region. Used in delayed-copy collectors such as compacting collectors.
    
    Parameters:
    
    from - The object to be copied.
    
    to - The region to be copied to.
    
    Returns:
    
    The resulting reference.
  - getSizeWhenCopied
```
public abstract int getSizeWhenCopied(ObjectReference object)
```
    Return the size required to copy an object
    
    Parameters:
    
    object - The object whose size is to be queried
    
    Returns:
    
    The size required to copy obj
  - getAlignWhenCopied
```
public abstract int getAlignWhenCopied(ObjectReference object)
```
    Return the alignment requirement for a copy of this object
    
    Parameters:
    
    object - The object whose size is to be queried
    
    Returns:
    
    The alignment required for a copy of obj
  - getAlignOffsetWhenCopied
```
public abstract int getAlignOffsetWhenCopied(ObjectReference object)
```
    Return the alignment offset requirements for a copy of this object
    
    Parameters:
    
    object - The object whose size is to be queried
    
    Returns:
    
    The alignment offset required for a copy of obj
  - getCurrentSize
```
public abstract int getCurrentSize(ObjectReference object)
```
    Return the size used by an object
    
    Parameters:
    
    object - The object whose size is to be queried
    
    Returns:
    
    The size of obj
  - getNextObject
```
public abstract ObjectReference getNextObject(ObjectReference object)
```
    Parameters:
    
    object - the current object
    
    Returns:
    
    the object reference for the next object in the heap under contiguous allocation
  - getObjectFromStartAddress
```
public abstract ObjectReference getObjectFromStartAddress(Address start)
```
    Parameters:
    
    start - the start address of the object
    
    Returns:
    
    an object reference from knowledge of the low order word
  - getObjectEndAddress
```
public abstract Address getObjectEndAddress(ObjectReference object)
```
    Gets a pointer to the address just past the end of the object.
    
    Parameters:
    
    object - The object
    
    Returns:
    
    the address of the first word after the the object
  - getTypeDescriptor
```
public abstract byte[] getTypeDescriptor(ObjectReference ref)
```
    Get the type descriptor for an object.
    
    Parameters:
    
    ref - address of the object
    
    Returns:
    
    byte array with the type descriptor
  - isArray
```
public abstract boolean isArray(ObjectReference object)
```
    Parameters:
    
    object - address of the object
    
    Returns:
    
    whether the passed object is an array
  - isPrimitiveArray
```
public abstract boolean isPrimitiveArray(ObjectReference object)
```
    Parameters:
    
    object - address of the object
    
    Returns:
    
    whether the passed object is a primitive array
  - getArrayLength
```
public abstract int getArrayLength(ObjectReference object)
```
    Get the length of an array object.
    
    Parameters:
    
    object - address of the object
    
    Returns:
    
    The array length, in elements
  - attemptAvailableBits
```
public abstract boolean attemptAvailableBits(ObjectReference object,
                                             Word oldVal,
                                             Word newVal)
```
    Attempts to set the bits available for memory manager use in an object. The attempt will only be successful if the current value of the bits matches oldVal. The comparison with the current value and setting are atomic with respect to other allocators.
    
    Parameters:
    
    object - the address of the object
    
    oldVal - the required current value of the bits
    
    newVal - the desired new value of the bits
    
    Returns:
    
    true if the bits were set, false otherwise
  - prepareAvailableBits
```
public abstract Word prepareAvailableBits(ObjectReference object)
```
    Gets the value of bits available for memory manager use in an object, in preparation for setting those bits.
    
    Parameters:
    
    object - the address of the object
    
    Returns:
    
    the value of the bits
  - writeAvailableByte
```
public abstract void writeAvailableByte(ObjectReference object,
                                        byte val)
```
    Sets the byte available for memory manager use in an object.
    
    Parameters:
    
    object - the address of the object
    
    val - the new value of the byte
  - readAvailableByte
```
public abstract byte readAvailableByte(ObjectReference object)
```
    Read the byte available for memory manager use in an object.
    
    Parameters:
    
    object - the address of the object
    
    Returns:
    
    the value of the byte
  - writeAvailableBitsWord
```
public abstract void writeAvailableBitsWord(ObjectReference object,
                                            Word val)
```
    Sets the bits available for memory manager use in an object.
    
    Parameters:
    
    object - the address of the object
    
    val - the new value of the bits
  - readAvailableBitsWord
```
public abstract Word readAvailableBitsWord(ObjectReference object)
```
    Read the bits available for memory manager use in an object.
    
    Parameters:
    
    object - the address of the object
    
    Returns:
    
    the value of the bits
  - GC_HEADER_OFFSET
```
public abstract Offset GC_HEADER_OFFSET()
```
    Gets the offset of the memory management header from the object reference address. XXX The object model / memory manager interface should be improved so that the memory manager does not need to know this.
    
    Returns:
    
    the offset, relative the object reference address
  - objectStartRef
```
public abstract Address objectStartRef(ObjectReference object)
```
    Returns the lowest address of the storage associated with an object.
    
    Parameters:
    
    object - the reference address of the object
    
    Returns:
    
    the lowest address of the object
  - refToAddress
```
public abstract Address refToAddress(ObjectReference object)
```
    Returns an address guaranteed to be inside the storage assocatied with and object.
    
    Parameters:
    
    object - the reference address of the object
    
    Returns:
    
    an address inside the object
  - isAcyclic
```
public abstract boolean isAcyclic(ObjectReference typeRef)
```
    Checks if a reference of the given type in another object is inherently acyclic. The type is given as a TIB.
    
    Parameters:
    
    typeRef - the type of the reference (as a TIB)
    
    Returns:
    
    true if a reference of the type is inherently acyclic
  - dumpObject
```
public abstract void dumpObject(ObjectReference object)
```
    Dump debugging information for an object.
    
    Parameters:
    
    object - The object whose information is to be dumped
  - getArrayBaseOffset
```
protected abstract Offset getArrayBaseOffset()
```
    Returns:
    
    The offset from array reference to element zero
  - arrayBaseOffsetTrapdoor
```
static Offset arrayBaseOffsetTrapdoor(ObjectModel o)
```

Class ObjectModel

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ObjectModel

Method Detail

copy

copyTo

getReferenceWhenCopiedTo

getSizeWhenCopied

getAlignWhenCopied

getAlignOffsetWhenCopied

getCurrentSize

getNextObject

getObjectFromStartAddress

getObjectEndAddress

getTypeDescriptor

isArray

isPrimitiveArray

getArrayLength

attemptAvailableBits

prepareAvailableBits

writeAvailableByte

readAvailableByte

writeAvailableBitsWord

readAvailableBitsWord

GC_HEADER_OFFSET

objectStartRef

refToAddress

isAcyclic

dumpObject

getArrayBaseOffset

arrayBaseOffsetTrapdoor