org.jikesrvm.mm.mmtk

Class Barriers

java.lang.Object

org.mmtk.vm.Barriers

org.jikesrvm.mm.mmtk.Barriers

public class Barriers
extends Barriers

Constructor Summary

Constructors

Constructor and Description
Barriers()

Method Summary

Modifier and Type	Method and Description
Address	addressRead(ObjectReference ref, Word offset, Word location, int mode) Perform the actual read of the read barrier, returning the value as a raw Address.
boolean	addressTryCompareAndSwap(ObjectReference objref, Address expected, Address newValue, Word offset, Word unused, int mode) Attempt an atomic compare and exchange in a write barrier sequence.
void	addressWrite(ObjectReference ref, Address target, Word offset, Word location, int mode) Perform the actual write of the write barrier, writing the value as a raw Address.
boolean	booleanRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a boolean read barrier.
void	booleanWrite(ObjectReference objref, boolean value, Word offset, Word location, int mode) Perform the actual write of a boolean write barrier.
byte	byteRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a byte read barrier.
void	byteWrite(ObjectReference objref, byte value, Word offset, Word location, int mode) Perform the actual write of a byte write barrier.
char	charRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a char read barrier.
void	charWrite(ObjectReference objref, char value, Word offset, Word location, int mode) Perform the actual write of a char write barrier.
double	doubleRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a double read barrier.
void	doubleWrite(ObjectReference objref, double value, Word offset, Word location, int mode) Perform the actual write of a double write barrier.
Extent	extentRead(ObjectReference ref, Word offset, Word location, int mode) Perform the actual read of the read barrier, returning the value as a raw Extent.
void	extentWrite(ObjectReference ref, Extent target, Word offset, Word location, int mode) Perform the actual write of the write barrier, writing the value as a raw Extent.
float	floatRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a float read barrier.
void	floatWrite(ObjectReference objref, float value, Word offset, Word location, int mode) Perform the actual write of a float write barrier.
int	intRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a int read barrier.
boolean	intTryCompareAndSwap(ObjectReference objref, int expected, int newValue, Word offset, Word unused, int mode) Attempt an atomic compare and exchange in a write barrier sequence.
void	intWrite(ObjectReference objref, int value, Word offset, Word location, int mode) Perform the actual write of a int write barrier.
long	longRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a long read barrier.
boolean	longTryCompareAndSwap(ObjectReference objref, long expected, long newValue, Word offset, Word unused, int mode) Attempt an atomic compare and exchange in a write barrier sequence.
void	longWrite(ObjectReference objref, long value, Word offset, Word location, int mode) Perform the actual write of a long write barrier.
void	objectArrayStoreNoGCBarrier(Object[] dst, int index, Object value) Sets an element of an object array without invoking any write barrier.
ObjectReference	objectReferenceAtomicWrite(ObjectReference objref, ObjectReference target, Word offset, Word unused, int mode) Atomically write a reference field of an object or array and return the old value of the reference field.
void	objectReferenceNonHeapWrite(Address slot, ObjectReference target, Word unusedA, Word unusedB) Perform the actual write of the non-heap write barrier.
ObjectReference	objectReferenceRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of an object reference read barrier.
boolean	objectReferenceTryCompareAndSwap(ObjectReference objref, ObjectReference old, ObjectReference target, Word offset, Word unused, int mode) Attempt an atomic compare and exchange in a write barrier sequence.
void	objectReferenceWrite(ObjectReference objref, ObjectReference value, Word offset, Word location, int mode) Perform the actual write of an object reference write barrier.
Offset	offsetRead(ObjectReference ref, Word offset, Word location, int mode) Perform the actual read of the read barrier, returning the value as a raw Offset.
void	offsetWrite(ObjectReference ref, Offset target, Word offset, Word location, int mode) Perform the actual write of the write barrier, writing the value as a raw Offset.
short	shortRead(ObjectReference objref, Word offset, Word location, int mode) Perform the actual read of a short read barrier.
void	shortWrite(ObjectReference objref, short value, Word offset, Word location, int mode) Perform the actual write of a short write barrier.
Word	wordAtomicWrite(ObjectReference ref, Word target, Word offset, Word unused, int mode) Atomically write a raw reference field of an object or array and return the old value of the reference field.
Word	wordRead(ObjectReference ref, Word offset, Word location, int mode) Perform the actual read of the read barrier, returning the value as a raw Word.
boolean	wordTryCompareAndSwap(ObjectReference ref, Word old, Word target, Word offset, Word unused, int mode) Attempt an atomic compare and exchange in a write barrier sequence.
void	wordWrite(ObjectReference ref, Word target, Word offset, Word location, int mode) Perform the actual write of the write barrier, writing the value as a raw Word.

Methods inherited from class java.lang.Object

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

Constructor Detail

Barriers

public Barriers()

Method Detail

booleanWrite

public final void booleanWrite(ObjectReference objref,
                               boolean value,
                               Word offset,
                               Word location,
                               int mode)

Perform the actual write of a boolean write barrier.

Specified by:

booleanWrite in class Barriers

Parameters:

objref - The object that has the boolean field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

booleanRead

public final boolean booleanRead(ObjectReference objref,
                                 Word offset,
                                 Word location,
                                 int mode)

Perform the actual read of a boolean read barrier.

Specified by:

booleanRead in class Barriers

Parameters:

objref - The object that has the boolean field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

byteWrite

public final void byteWrite(ObjectReference objref,
                            byte value,
                            Word offset,
                            Word location,
                            int mode)

Perform the actual write of a byte write barrier.

Specified by:

byteWrite in class Barriers

Parameters:

objref - The object that has the byte field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

byteRead

public final byte byteRead(ObjectReference objref,
                           Word offset,
                           Word location,
                           int mode)

Perform the actual read of a byte read barrier.

Specified by:

byteRead in class Barriers

Parameters:

objref - The object that has the byte field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

charWrite

public final void charWrite(ObjectReference objref,
                            char value,
                            Word offset,
                            Word location,
                            int mode)

Perform the actual write of a char write barrier.

Specified by:

charWrite in class Barriers

Parameters:

objref - The object that has the char field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

charRead

public final char charRead(ObjectReference objref,
                           Word offset,
                           Word location,
                           int mode)

Perform the actual read of a char read barrier.

Specified by:

charRead in class Barriers

Parameters:

objref - The object that has the char field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

shortWrite

public final void shortWrite(ObjectReference objref,
                             short value,
                             Word offset,
                             Word location,
                             int mode)

Perform the actual write of a short write barrier.

Specified by:

shortWrite in class Barriers

Parameters:

objref - The object that has the short field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

shortRead

public final short shortRead(ObjectReference objref,
                             Word offset,
                             Word location,
                             int mode)

Perform the actual read of a short read barrier.

Specified by:

shortRead in class Barriers

Parameters:

objref - The object that has the short field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

intWrite

public final void intWrite(ObjectReference objref,
                           int value,
                           Word offset,
                           Word location,
                           int mode)

Perform the actual write of a int write barrier.

Specified by:

intWrite in class Barriers

Parameters:

objref - The object that has the int field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

intRead

public final int intRead(ObjectReference objref,
                         Word offset,
                         Word location,
                         int mode)

Perform the actual read of a int read barrier.

Specified by:

intRead in class Barriers

Parameters:

objref - The object that has the int field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

intTryCompareAndSwap

public boolean intTryCompareAndSwap(ObjectReference objref,
                                    int expected,
                                    int newValue,
                                    Word offset,
                                    Word unused,
                                    int mode)

Attempt an atomic compare and exchange in a write barrier sequence.

Specified by:

intTryCompareAndSwap in class Barriers

Parameters:

objref - The object that has the int field

expected - The old int to be swapped out

newValue - the new int

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

True if the compare and swap was successful

longWrite

public final void longWrite(ObjectReference objref,
                            long value,
                            Word offset,
                            Word location,
                            int mode)

Perform the actual write of a long write barrier.

Specified by:

longWrite in class Barriers

Parameters:

objref - The object that has the long field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

longRead

public final long longRead(ObjectReference objref,
                           Word offset,
                           Word location,
                           int mode)

Perform the actual read of a long read barrier.

Specified by:

longRead in class Barriers

Parameters:

objref - The object that has the long field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

longTryCompareAndSwap

public boolean longTryCompareAndSwap(ObjectReference objref,
                                     long expected,
                                     long newValue,
                                     Word offset,
                                     Word unused,
                                     int mode)

Attempt an atomic compare and exchange in a write barrier sequence.

Specified by:

longTryCompareAndSwap in class Barriers

Parameters:

objref - The object that has the long field

expected - The old long to be swapped out

newValue - the new long

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

True if the compare and swap was successful

floatWrite

public final void floatWrite(ObjectReference objref,
                             float value,
                             Word offset,
                             Word location,
                             int mode)

Perform the actual write of a float write barrier.

Specified by:

floatWrite in class Barriers

Parameters:

objref - The object that has the float field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

floatRead

public final float floatRead(ObjectReference objref,
                             Word offset,
                             Word location,
                             int mode)

Perform the actual read of a float read barrier.

Specified by:

floatRead in class Barriers

Parameters:

objref - The object that has the float field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

doubleWrite

public final void doubleWrite(ObjectReference objref,
                              double value,
                              Word offset,
                              Word location,
                              int mode)

Perform the actual write of a double write barrier.

Specified by:

doubleWrite in class Barriers

Parameters:

objref - The object that has the double field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The FieldReference index to assist the store

mode - The context in which the write is occurring

doubleRead

public final double doubleRead(ObjectReference objref,
                               Word offset,
                               Word location,
                               int mode)

Perform the actual read of a double read barrier.

Specified by:

doubleRead in class Barriers

Parameters:

objref - The object that has the double field

offset - The offset from the ref

location - Unused

mode - The context in which the write is occurring

Returns:

the read value

objectReferenceWrite

public final void objectReferenceWrite(ObjectReference objref,
                                       ObjectReference value,
                                       Word offset,
                                       Word location,
                                       int mode)

Perform the actual write of an object reference write barrier.

Specified by:

objectReferenceWrite in class Barriers

Parameters:

objref - The object that has the reference field

value - The value that the slot will be updated to

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

objectReferenceRead

public final ObjectReference objectReferenceRead(ObjectReference objref,
                                                 Word offset,
                                                 Word location,
                                                 int mode)

Perform the actual read of an object reference read barrier.

Specified by:

objectReferenceRead in class Barriers

Parameters:

objref - The object that has the reference field

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

Returns:

the object reference read value

objectReferenceNonHeapWrite

public final void objectReferenceNonHeapWrite(Address slot,
                                              ObjectReference target,
                                              Word unusedA,
                                              Word unusedB)

Perform the actual write of the non-heap write barrier. This is used when the store is not to an object, but to a non-heap location such as statics or the stack.

Specified by:

objectReferenceNonHeapWrite in class Barriers

Parameters:

slot - The slot to be updated

target - The value that the slot will be updated to

unusedA - Unused

unusedB - Unused

objectReferenceAtomicWrite

public final ObjectReference objectReferenceAtomicWrite(ObjectReference objref,
                                                        ObjectReference target,
                                                        Word offset,
                                                        Word unused,
                                                        int mode)

Atomically write a reference field of an object or array and return the old value of the reference field.

Specified by:

objectReferenceAtomicWrite in class Barriers

Parameters:

objref - The object that has the reference field

target - The value that the slot will be updated to

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

The value that was replaced by the write.

objectReferenceTryCompareAndSwap

public final boolean objectReferenceTryCompareAndSwap(ObjectReference objref,
                                                      ObjectReference old,
                                                      ObjectReference target,
                                                      Word offset,
                                                      Word unused,
                                                      int mode)

Attempt an atomic compare and exchange in a write barrier sequence.

Specified by:

objectReferenceTryCompareAndSwap in class Barriers

Parameters:

objref - The object that has the reference field

old - The old reference to be swapped out

target - The value that the slot will be updated to

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

True if the compare and swap was successful

wordWrite

public final void wordWrite(ObjectReference ref,
                            Word target,
                            Word offset,
                            Word location,
                            int mode)

Perform the actual write of the write barrier, writing the value as a raw Word.

Specified by:

wordWrite in class Barriers

Parameters:

ref - The object that has the Word field

target - The value that the slot will be updated to

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

wordAtomicWrite

public final Word wordAtomicWrite(ObjectReference ref,
                                  Word target,
                                  Word offset,
                                  Word unused,
                                  int mode)

Atomically write a raw reference field of an object or array and return the old value of the reference field.

Specified by:

wordAtomicWrite in class Barriers

Parameters:

ref - The object that has the Word field

target - The value that the slot will be updated to

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

The value that was replaced by the write.

wordTryCompareAndSwap

public final boolean wordTryCompareAndSwap(ObjectReference ref,
                                           Word old,
                                           Word target,
                                           Word offset,
                                           Word unused,
                                           int mode)

Attempt an atomic compare and exchange in a write barrier sequence.

Specified by:

wordTryCompareAndSwap in class Barriers

Parameters:

ref - The object that has the Word field

old - The old Word to be swapped out

target - The value that the slot will be updated to

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

True if the compare and swap was successful

wordRead

public final Word wordRead(ObjectReference ref,
                           Word offset,
                           Word location,
                           int mode)

Perform the actual read of the read barrier, returning the value as a raw Word.

Specified by:

wordRead in class Barriers

Parameters:

ref - The object that has the Word field

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

Returns:

the read value

addressWrite

public final void addressWrite(ObjectReference ref,
                               Address target,
                               Word offset,
                               Word location,
                               int mode)

Perform the actual write of the write barrier, writing the value as a raw Address.

Specified by:

addressWrite in class Barriers

Parameters:

ref - The object that has the Address field

target - The value that the slot will be updated to

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

addressRead

public final Address addressRead(ObjectReference ref,
                                 Word offset,
                                 Word location,
                                 int mode)

Perform the actual read of the read barrier, returning the value as a raw Address.

Specified by:

addressRead in class Barriers

Parameters:

ref - The object that has the Address field

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

Returns:

the read value

addressTryCompareAndSwap

public boolean addressTryCompareAndSwap(ObjectReference objref,
                                        Address expected,
                                        Address newValue,
                                        Word offset,
                                        Word unused,
                                        int mode)

Attempt an atomic compare and exchange in a write barrier sequence.

Specified by:

addressTryCompareAndSwap in class Barriers

Parameters:

objref - The object that has the Address field

expected - The old Address to be swapped out

newValue - the new Address

offset - The offset from the ref

unused - Unused

mode - The context in which the write is occurring

Returns:

True if the compare and swap was successful

offsetWrite

public final void offsetWrite(ObjectReference ref,
                              Offset target,
                              Word offset,
                              Word location,
                              int mode)

Perform the actual write of the write barrier, writing the value as a raw Offset.

Specified by:

offsetWrite in class Barriers

Parameters:

ref - The object that has the Offset field

target - The value that the slot will be updated to

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

offsetRead

public final Offset offsetRead(ObjectReference ref,
                               Word offset,
                               Word location,
                               int mode)

Perform the actual read of the read barrier, returning the value as a raw Offset.

Specified by:

offsetRead in class Barriers

Parameters:

ref - The object that has the Offset field

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

Returns:

the read value

extentWrite

public final void extentWrite(ObjectReference ref,
                              Extent target,
                              Word offset,
                              Word location,
                              int mode)

Perform the actual write of the write barrier, writing the value as a raw Extent.

Specified by:

extentWrite in class Barriers

Parameters:

ref - The object that has the Extent field

target - The value that the slot will be updated to

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

extentRead

public final Extent extentRead(ObjectReference ref,
                               Word offset,
                               Word location,
                               int mode)

Perform the actual read of the read barrier, returning the value as a raw Extent.

Specified by:

extentRead in class Barriers

Parameters:

ref - The object that has the Extent field

offset - The offset from the ref

location - The index of the FieldReference

mode - The context in which the write is occurring

Returns:

the read value

objectArrayStoreNoGCBarrier

public final void objectArrayStoreNoGCBarrier(Object[] dst,
                                              int index,
                                              Object value)

Sets an element of an object array without invoking any write barrier. This method is called by the Map class to ensure potentially-allocation-triggering write barriers do not occur in allocation slow path code.

Specified by:

objectArrayStoreNoGCBarrier in class Barriers

Parameters:

dst - the destination array

index - the index of the element to set

value - the new value for the element