com.oracle.graal.hotspot.nodes

Class DirectCompareAndSwapNode

java.lang.Object

com.oracle.graal.graph.Node

com.oracle.graal.nodes.ValueNode

com.oracle.graal.nodes.FixedNode

com.oracle.graal.nodes.FixedWithNextNode

com.oracle.graal.hotspot.nodes.DirectCompareAndSwapNode

All Implemented Interfaces:

NodeInterface, MemoryCheckpoint, MemoryCheckpoint.Single, MemoryNode, LIRLowerable, Cloneable, Formattable, KindProvider

public final class DirectCompareAndSwapNode
extends FixedWithNextNode
implements LIRLowerable, MemoryCheckpoint.Single

A special purpose store node that differs from CompareAndSwapNode in that it is not a StateSplit and it #compareAndSwap(Address, Word, Word, LocationIdentity) returns either the expected value or the compared against value instead of a boolean.

Nested Class Summary

Nested classes/interfaces inherited from class com.oracle.graal.graph.Node

Node.ConstantNodeParameter, Node.InjectedNodeParameter, Node.Input, Node.NodeIntrinsic, Node.OptionalInput, Node.Successor, Node.ValueNumberable

Nested classes/interfaces inherited from interface com.oracle.graal.nodes.memory.MemoryCheckpoint

MemoryCheckpoint.Multi, MemoryCheckpoint.Single, MemoryCheckpoint.TypeAssertion

Field Summary

Fields

Modifier and Type	Field and Description
(package private) AddressNode	address
(package private) ValueNode	expectedValue
protected LocationIdentity	locationIdentity
(package private) ValueNode	newValue
static NodeClass<DirectCompareAndSwapNode>	TYPE

Fields inherited from class com.oracle.graal.nodes.FixedWithNextNode

next

Fields inherited from class com.oracle.graal.nodes.ValueNode

stamp

Fields inherited from class com.oracle.graal.graph.Node

NODE_LIST, NOT_ITERABLE, USE_UNSAFE_TO_CLONE, WithAllEdges, WithNoEdges, WithOnlyInputEdges, WithOnlySucessorEdges

Constructor Summary

Constructors

Constructor and Description
DirectCompareAndSwapNode(ValueNode address, ValueNode expected, ValueNode newValue, LocationIdentity locationIdentity)

Method Summary

Modifier and Type	Method and Description
static Word	compareAndSwap(AddressNode.Address address, Word expectedValue, Word newValue, LocationIdentity locationIdentity) Compares an expected value with the actual value in a location denoted by an address.
ValueNode	expectedValue()
void	generate(NodeLIRBuilderTool gen)
AddressNode	getAddress()
LocationIdentity	getLocationIdentity() This method is used to determine which memory location is killed by this node.
ValueNode	newValue()

Methods inherited from class com.oracle.graal.nodes.FixedWithNextNode

asNode, next, setNext

Methods inherited from class com.oracle.graal.nodes.FixedNode

verify

Methods inherited from class com.oracle.graal.nodes.ValueNode

asConstant, asJavaConstant, getKind, graph, inferStamp, isAllowedUsageType, isConstant, isConstantPredicate, isNullConstant, setStamp, stamp, updateStamp

Methods inherited from class com.oracle.graal.graph.Node

acceptInputs, acceptSuccessors, afterClone, assertFalse, assertTrue, cfgPredecessors, cfgSuccessors, clearInputs, clearSuccessors, copyWithInputs, copyWithInputs, equals, fail, formatTo, getDebugProperties, getDebugProperties, getId, getNodeClass, getUsageAt, getUsageCount, hashCode, hasNoUsages, hasUsages, inputs, isAlive, isDeleted, markDeleted, modCount, newIdentityMap, newIdentityMap, newIdentityMap, newMap, newMap, newMap, newSet, newSet, predecessor, pushInputs, removeUsage, replaceAndDelete, replaceAtMatchingUsages, replaceAtPredecessor, replaceAtUsages, replaceAtUsages, replaceAtUsages, replaceFirstInput, replaceFirstSuccessor, safeDelete, simplify, successors, toString, toString, updatePredecessor, updateUsages, updateUsagesInterface, usages, valueEquals, verifyEdges, verifyInputs

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.oracle.graal.nodes.memory.MemoryCheckpoint

asNode

Field Detail

TYPE

public static final NodeClass<DirectCompareAndSwapNode> TYPE

address

AddressNode address

expectedValue

ValueNode expectedValue

newValue

ValueNode newValue

locationIdentity

protected final LocationIdentity locationIdentity

Constructor Detail

DirectCompareAndSwapNode

public DirectCompareAndSwapNode(ValueNode address,
                                ValueNode expected,
                                ValueNode newValue,
                                LocationIdentity locationIdentity)

Method Detail

getAddress

public AddressNode getAddress()

expectedValue

public ValueNode expectedValue()

newValue

public ValueNode newValue()

getLocationIdentity

public LocationIdentity getLocationIdentity()

Description copied from interface: MemoryCheckpoint.Single

This method is used to determine which memory location is killed by this node. Returning the special value LocationIdentity.any() will kill all memory locations.

Specified by:

getLocationIdentity in interface MemoryCheckpoint.Single

Returns:

the identity of the location killed by this node.

generate

public void generate(NodeLIRBuilderTool gen)

Specified by:

generate in interface LIRLowerable

compareAndSwap

public static Word compareAndSwap(AddressNode.Address address,
                                  Word expectedValue,
                                  Word newValue,
                                  LocationIdentity locationIdentity)

Compares an expected value with the actual value in a location denoted by an address. Iff they are same, newValue is placed into the location and the expectedValue is returned. Otherwise, the actual value is returned. All of the above is performed in one atomic hardware transaction.

Parameters:

address - the address to be atomically tested and updated

expectedValue - if this value is currently in the field, perform the swap

newValue - the new value to put into the field

Returns:

either expectedValue or the actual value