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package org.graalvm.compiler.nodes.memory;

import org.graalvm.compiler.core.common.LocationIdentity;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.FrameState;
import org.graalvm.compiler.nodes.extended.GuardingNode;
import org.graalvm.compiler.nodes.memory.address.AddressNode;

An FixedAccessNode that can be converted to a FloatingAccessNode.
/** * An {@link FixedAccessNode} that can be converted to a {@link FloatingAccessNode}. */
@NodeInfo public abstract class FloatableAccessNode extends FixedAccessNode { public static final NodeClass<FloatableAccessNode> TYPE = NodeClass.create(FloatableAccessNode.class); protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp) { super(c, address, location, stamp); } protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp, GuardingNode guard, BarrierType barrierType) { super(c, address, location, stamp, guard, barrierType, false, null); } protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp, GuardingNode guard, BarrierType barrierType, boolean nullCheck, FrameState stateBefore) { super(c, address, location, stamp, guard, barrierType, nullCheck, stateBefore); } public abstract FloatingAccessNode asFloatingNode(MemoryNode lastLocationAccess); protected boolean forceFixed; public void setForceFixed(boolean flag) { this.forceFixed = flag; }
AccessNodes can float only if their location identities are not ANY_LOCATION. Furthermore, in case G1 is enabled any access (read) to the java.lang.ref.Reference.referent field which has an attached write barrier with pre-semantics can not also float.
/** * AccessNodes can float only if their location identities are not ANY_LOCATION. Furthermore, in * case G1 is enabled any access (read) to the java.lang.ref.Reference.referent field which has * an attached write barrier with pre-semantics can not also float. */
public boolean canFloat() { return !forceFixed && getLocationIdentity().isSingle() && getBarrierType() == BarrierType.NONE; } }