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comparison graal/com.oracle.truffle.api/src/com/oracle/truffle/api/CompilerDirectives.java @ 9244:8f540423a5be

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Added two new classes to the Truffle API: CompilerDirectives and CompilerAsserts.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Tue, 23 Apr 2013 11:20:53 +0200
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children f5e58a1eca55
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9243:136cc8fd8890 9244:8f540423a5be
1 /*
2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.oracle.truffle.api;
24
25 import java.util.concurrent.*;
26
27 /**
28 * Directives that influence the optimizations of the Truffle compiler. All of the operations have
29 * no effect when executed in the Truffle interpreter.
30 */
31 public class CompilerDirectives {
32
33 private static final double SLOWPATH_PROBABILITY = 0.0001;
34
35 /**
36 * Directive for the compiler to discontinue compilation at this code position and instead
37 * insert a transfer to the interpreter.
38 */
39 public static void transferToInterpreter() {
40 }
41
42 /**
43 * Directive for the compiler that the given runnable should only be executed in the interpreter
44 * and ignored in the compiled code.
45 *
46 * @param runnable the closure that should only be executed in the interpreter
47 */
48 public static void interpreterOnly(Runnable runnable) {
49 runnable.run();
50 }
51
52 /**
53 * Directive for the compiler that the given callable should only be executed in the
54 * interpreter.
55 *
56 * @param callable the closure that should only be executed in the interpreter
57 * @return the result of executing the closure in the interpreter and null in the compiled code
58 * @throws Exception If the closure throws an exception when executed in the interpreter.
59 */
60 public static <T> T interpreterOnly(Callable<T> callable) throws Exception {
61 return callable.call();
62 }
63
64 /**
65 * Directive for the compiler that the current path has a very low probability to be executed.
66 */
67 public static void slowpath() {
68 injectBranchProbability(SLOWPATH_PROBABILITY);
69 }
70
71 /**
72 * Injects a probability for the current path into the probability information of the
73 * immediately preceeding branch instruction.
74 *
75 * @param probability the probability value between 0.0 and 1.0 that should be injected
76 */
77 public static void injectBranchProbability(double probability) {
78 assert probability >= 0.0 && probability <= 1.0;
79 }
80 }