| /* |
| * Copyright (c) 2012, 2014, 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 jdk.vm.ci.meta; |
| |
| /** |
| * Manages unique deoptimization reasons. Reasons are embedded in compiled code and can be |
| * invalidated at run time. Subsequent compilations then should not speculate again on such |
| * invalidated reasons to avoid repeated deoptimization. |
| * |
| * All methods of this interface are called by the compiler. There is no need for API to register |
| * failed speculations during deoptimization, since every VM has different needs there. |
| */ |
| public interface SpeculationLog { |
| /** |
| * Marker interface for speculation objects that can be added to the speculation log. |
| */ |
| public interface SpeculationReason { |
| } |
| |
| /** |
| * Marker class that indicates that a speculation has no reason. |
| */ |
| final class NoSpeculationReason implements SpeculationReason { |
| } |
| |
| class Speculation { |
| private SpeculationReason reason; |
| |
| public Speculation(SpeculationReason reason) { |
| this.reason = reason; |
| } |
| |
| public SpeculationReason getReason() { |
| return reason; |
| } |
| |
| @Override |
| public String toString() { |
| return reason.toString(); |
| } |
| } |
| |
| Speculation NO_SPECULATION = new Speculation(new NoSpeculationReason()); |
| |
| /** |
| * Must be called before compilation, i.e., before a compiler calls {@link #maySpeculate}. |
| */ |
| void collectFailedSpeculations(); |
| |
| /** |
| * If this method returns true, the compiler is allowed to {@link #speculate} with the given |
| * reason. |
| */ |
| boolean maySpeculate(SpeculationReason reason); |
| |
| /** |
| * Registers a speculation performed by the compiler. The compiler must guard every call to this |
| * method for a specific reason with a call to {@link #maySpeculate(SpeculationReason)}. |
| * |
| * This API is subject to a benign race where a during the course of a compilation another |
| * thread might fail a speculation such that {@link #maySpeculate(SpeculationReason)} will |
| * return false but an earlier call returned true. This method will still return a working |
| * {@link Speculation} in that case but the compile will eventually be invalidated and the |
| * compile attempted again without the now invalid speculation. |
| * |
| * @param reason an object representing the reason for the speculation |
| * @return a compiler constant encapsulating the provided reason. It is usually passed as an |
| * argument to the deoptimization function. |
| */ |
| Speculation speculate(SpeculationReason reason); |
| |
| /** |
| * Returns if this log has speculations. |
| * |
| * @return true if there are speculations, false otherwise |
| */ |
| boolean hasSpeculations(); |
| |
| /** |
| * Given a {@link JavaConstant} previously returned from |
| * {@link MetaAccessProvider#encodeSpeculation(Speculation)} return the original |
| * {@link Speculation} object. |
| */ |
| Speculation lookupSpeculation(JavaConstant constant); |
| } |