Mercurial > hg > truffle
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/GuardNode.java @ 11396:a268b0de65d6
Add some javadoc for GuardLoweringPhase, ConvertDeoptimizeToGuardPhase and DeoptimizeNode
author | Gilles Duboscq <duboscq@ssw.jku.at> |
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date | Thu, 22 Aug 2013 15:22:26 +0200 |
parents | 0531aa5ae1cd |
children | 1f302b6e16b0 |
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/* * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.graal.nodes; import com.oracle.graal.api.code.*; import com.oracle.graal.api.meta.*; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.extended.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.nodes.type.*; /** * 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). */ @NodeInfo(nameTemplate = "Guard(!={p#negated}) {p#reason/s}") public final class GuardNode extends FloatingGuardedNode implements Canonicalizable, Node.IterableNodeType, Negatable, GuardingNode, GuardedNode { @Input private LogicNode condition; private final DeoptimizationReason reason; private final DeoptimizationAction action; private boolean negated; public GuardNode(LogicNode condition, GuardingNode anchor, DeoptimizationReason reason, DeoptimizationAction action, boolean negated) { super(StampFactory.dependency(), anchor); this.condition = condition; this.reason = reason; this.action = action; this.negated = negated; } /** * The instruction that produces the tested boolean value. */ public LogicNode condition() { return condition; } public void setCondition(LogicNode x) { updateUsages(condition, x); condition = x; } public boolean negated() { return negated; } public DeoptimizationReason reason() { return reason; } public DeoptimizationAction action() { return action; } @Override public String toString(Verbosity verbosity) { if (verbosity == Verbosity.Name && negated) { return "!" + super.toString(verbosity); } else { return super.toString(verbosity); } } @Override public ValueNode canonical(CanonicalizerTool tool) { if (condition() instanceof LogicConstantNode) { LogicConstantNode c = (LogicConstantNode) condition(); if (c.getValue() != negated) { return graph().start(); } } return this; } @Override public Negatable negate(LogicNode cond) { assert cond == condition(); negated = !negated; return this; } }