com.oracle.graal.nodes

Class GuardNode

java.lang.Object

com.oracle.graal.graph.Node

com.oracle.graal.nodes.ValueNode

com.oracle.graal.nodes.calc.FloatingNode

com.oracle.graal.nodes.FloatingAnchoredNode

com.oracle.graal.nodes.GuardNode

All Implemented Interfaces:

Node.ValueNumberable, NodeInterface, Canonicalizable, GuardingNode, Cloneable, Formattable, KindProvider

public class GuardNode
extends FloatingAnchoredNode
implements Canonicalizable, GuardingNode

A guard is a node that deoptimizes based on a conditional expression. Guards are not attached to a certain frame state, they can move around freely and will always use the correct frame state when the nodes are scheduled (i.e., the last emitted frame state). The node that is guarded has a data dependency on the guard and the guard in turn has a data dependency on the condition. A guard may only be executed if it is guaranteed that the guarded node is executed too (if no exceptions are thrown). Therefore, an anchor is placed after a control flow split and the guard has a data dependency to the anchor. The anchor is the most distant node that is post-dominated by the guarded node and the guard can be scheduled anywhere between those two nodes. This ensures maximum flexibility for the guard node and guarantees that deoptimization occurs only if the control flow would have reached the guarded node (without taking exceptions into account).

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.graph.spi.Canonicalizable

Canonicalizable.Binary<T extends Node>, Canonicalizable.BinaryCommutative<T extends Node>, Canonicalizable.Unary<T extends Node>

Field Summary

Fields

Modifier and Type	Field and Description
protected DeoptimizationAction	action
protected LogicNode	condition
protected boolean	negated
protected DeoptimizationReason	reason
protected JavaConstant	speculation
static NodeClass<GuardNode>	TYPE

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

anchor

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

Modifier	Constructor and Description
	GuardNode(LogicNode condition, AnchoringNode anchor, DeoptimizationReason reason, DeoptimizationAction action, boolean negated, JavaConstant speculation)
protected	GuardNode(NodeClass<? extends GuardNode> c, LogicNode condition, AnchoringNode anchor, DeoptimizationReason reason, DeoptimizationAction action, boolean negated, JavaConstant speculation)

Method Summary

Modifier and Type	Method and Description
DeoptimizationAction	action()
Node	canonical(CanonicalizerTool tool) Implementations of this method can provide local optimizations like constant folding and strength reduction.
LogicNode	condition() The instruction that produces the tested boolean value.
JavaConstant	getSpeculation()
boolean	isNegated()
FixedWithNextNode	lowerGuard()
void	negate()
DeoptimizationReason	reason()
void	setAction(DeoptimizationAction invalidaterecompile)
void	setSpeculation(JavaConstant speculation)
String	toString(Verbosity verbosity) Creates a String representation for this node with a given Verbosity.

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

getAnchor, setAnchor

Methods inherited from class com.oracle.graal.nodes.calc.FloatingNode

asNode

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, updatePredecessor, updateUsages, updateUsagesInterface, usages, valueEquals, verify, 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.extended.GuardingNode

asNode

Field Detail

TYPE

public static final NodeClass<GuardNode> TYPE

condition

protected LogicNode condition

reason

protected final DeoptimizationReason reason

speculation

protected JavaConstant speculation

action

protected DeoptimizationAction action

negated

protected boolean negated

Constructor Detail

GuardNode

public GuardNode(LogicNode condition,
                 AnchoringNode anchor,
                 DeoptimizationReason reason,
                 DeoptimizationAction action,
                 boolean negated,
                 JavaConstant speculation)

GuardNode

protected GuardNode(NodeClass<? extends GuardNode> c,
                    LogicNode condition,
                    AnchoringNode anchor,
                    DeoptimizationReason reason,
                    DeoptimizationAction action,
                    boolean negated,
                    JavaConstant speculation)

Method Detail

condition

public LogicNode condition()

The instruction that produces the tested boolean value.

isNegated

public boolean isNegated()

reason

public DeoptimizationReason reason()

action

public DeoptimizationAction action()

getSpeculation

public JavaConstant getSpeculation()

setSpeculation

public void setSpeculation(JavaConstant speculation)

toString

public String toString(Verbosity verbosity)

Description copied from class: Node

Creates a String representation for this node with a given Verbosity.

Overrides:

toString in class Node

canonical

public Node canonical(CanonicalizerTool tool)

Description copied from interface: Canonicalizable

Implementations of this method can provide local optimizations like constant folding and strength reduction. Implementations should look at the properties and inputs of the current node and determine if there is a more optimal and always semantically correct replacement.
The return value determines the effect that the canonicalization will have:

• Returning an pre-existing node will replace the current node with the given one.
• Returning a newly created node (that was not yet added to the graph) will replace the current node with the given one, after adding it to the graph. If both the replacement and the replacee are anchored in control flow (fixed nodes), the replacement will be added to the control flow. It is invalid to replace a non-fixed node with a newly created fixed node (because its placement in the control flow cannot be determined without scheduling).
• Returning null will delete the current node and replace it with null at all usages. Note that it is not necessary to delete floating nodes that have no more usages this way - they will be deleted automatically.

Specified by:

canonical in interface Canonicalizable

Parameters:

tool - provides access to runtime interfaces like MetaAccessProvider

lowerGuard

public FixedWithNextNode lowerGuard()

negate

public void negate()

setAction

public void setAction(DeoptimizationAction invalidaterecompile)