Mercurial > hg > truffle
diff truffle/com.oracle.truffle.api.profiles/src/com/oracle/truffle/api/profiles/ValueProfile.java @ 22503:828c67903db2
Moving profiles into their own project to ensure the core API doesn't reference these utility classes.
author | Jaroslav Tulach <jaroslav.tulach@oracle.com> |
---|---|
date | Thu, 17 Dec 2015 10:01:38 +0100 |
parents | truffle/com.oracle.truffle.api/src/com/oracle/truffle/api/profiles/ValueProfile.java@a63bda98cfdb |
children | d80a5ff56f51 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/truffle/com.oracle.truffle.api.profiles/src/com/oracle/truffle/api/profiles/ValueProfile.java Thu Dec 17 10:01:38 2015 +0100 @@ -0,0 +1,334 @@ +/* + * Copyright (c) 2014, 2015, 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. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the LICENSE file that accompanied this code. + * + * 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.truffle.api.profiles; + +import java.util.Objects; + +import com.oracle.truffle.api.CompilerDirectives; +import com.oracle.truffle.api.CompilerDirectives.CompilationFinal; +import com.oracle.truffle.api.Truffle; + +/** + * <p> + * Specialized value profile to capture certain properties of <code>Object</code> runtime values. + * Value profiles require a runtime check in their initialized state to verify their profiled + * assumption. Value profiles are limited to capture monomorphic profiles only. This means that if + * two or more identities or classes are profiles within a single profile then the profile has no + * effect and no overhead after compilation. There are specialized versions of this profile with + * less interpreter footprint for {@link ConditionProfile boolean}, {@link ByteValueProfile byte}, + * {@link IntValueProfile int}, {@link LongValueProfile long}, {@link FloatValueProfile float} and + * {@link DoubleValueProfile double} values. + * </p> + * + * <p> + * <b> Usage example: </b> + * + * <pre> + * class SampleNode extends Node { + * + * final ValueProfile profile = ValueProfile.create{Identity,Class}Profile(); + * + * Object execute(Object input) { + * Object profiledValue = profile.profile(input); + * // compiler may know now more about profiledValue + * return profieldValue; + * } + * } + * </pre> + * <p> + * + * + * {@inheritDoc} + * + * @see #createIdentityProfile() + * @see #createClassProfile() + */ +public abstract class ValueProfile extends Profile { + + ValueProfile() { + } + + public abstract <T> T profile(T value); + + /** + * <p> + * Returns a value profile that profiles the exact class of a value. It will check the class of + * the profiled value and provide additional information to the compiler if only non-null values + * of exactly one concrete Java class are passed as a parameter to the + * {@link ValueProfile#profile} method. This can be beneficial if subsequent code can take + * advantage of knowing the concrete class of the value. The profile will degrade to the generic + * case if a null value or if at least two instances of two different Java classes are + * registered. + * </p> + * + * <p> + * <b>Compilation notes:</b> Value profiles require a runtime check in their initialized state + * to verify their profiled class. If two classes have been seen on a single profile instance + * then this profile will transition to a generic state with no overhead. + * </P> + * + * @see ValueProfile usage example + */ + public static ValueProfile createClassProfile() { + if (Truffle.getRuntime().isProfilingEnabled()) { + return ExactClass.create(); + } else { + return Disabled.INSTANCE; + } + } + + /** + * <p> + * Returns a value profile that profiles the object identity of a value. A single instance can + * only profile one particular instance. + * </p> + * + * <p> + * <b>Compilation notes:</b> Identity profiles require a runtime check to verify their profiled + * object identity. If two identities have been seen on a single profile instance then this + * profile will transition to a generic state with no overhead. + * </p> + */ + public static ValueProfile createIdentityProfile() { + if (Truffle.getRuntime().isProfilingEnabled()) { + return Identity.create(); + } else { + return Disabled.INSTANCE; + } + } + + /** + * <p> + * Returns a value profile that profiles the object equality of a value. A single instance can + * only profile one set of equal values. + * </p> + * + * <p> + * <b>Compilation notes:</b> Equality profiles inline the body of the equal method of the first + * profiled value in order to verify its assumption. Please take care that you do this only for + * equals implementations that your guest language actually has control over otherwise your + * compiled code might contain recursions or too much code. If two non equal objects have been + * seen on a single profile instance then this profile will transition to a generic state with + * no overhead. + * </p> + */ + public static ValueProfile createEqualityProfile() { + if (Truffle.getRuntime().isProfilingEnabled()) { + return Equality.create(); + } else { + return Disabled.INSTANCE; + } + } + + static final class Disabled extends ValueProfile { + + static final ValueProfile INSTANCE = new Disabled(); + + @Override + protected Object clone() { + return INSTANCE; + } + + @Override + public <T> T profile(T value) { + return value; + } + + @Override + public String toString() { + return toStringDisabled(ValueProfile.class); + } + + } + + static final class Equality extends ValueProfile { + + private static final Object GENERIC = new Object(); + + @CompilationFinal protected Object cachedValue = null; + + Equality() { + } + + @Override + @SuppressWarnings("unchecked") + public <T> T profile(T newValue) { + // Field needs to be cached in local variable for thread safety and startup speed. + Object cached = this.cachedValue; + if (cached != GENERIC) { + if (cached != null && cached.equals(newValue)) { + return (T) cached; + } else { + CompilerDirectives.transferToInterpreterAndInvalidate(); + if (cached == null && newValue != null) { + cachedValue = newValue; + } else { + cachedValue = GENERIC; + } + } + } + return newValue; + } + + public boolean isGeneric() { + return getCachedValue() == GENERIC; + } + + public boolean isUninitialized() { + return getCachedValue() == null; + } + + public Object getCachedValue() { + return cachedValue; + } + + @Override + public String toString() { + return toString(ValueProfile.class, isUninitialized(), isGeneric(), // + String.format("value == %s@%x", cachedValue != null ? cachedValue.getClass().getSimpleName() : "null", Objects.hash(cachedValue))); + } + + /* Needed for lazy class loading. */ + static ValueProfile create() { + return new Equality(); + } + + } + + static final class Identity extends ValueProfile { + + private static final Object UNINITIALIZED = new Object(); + private static final Object GENERIC = new Object(); + + @CompilationFinal protected Object cachedValue = UNINITIALIZED; + + Identity() { + } + + @Override + @SuppressWarnings("unchecked") + public <T> T profile(T newValue) { + // Field needs to be cached in local variable for thread safety and startup speed. + Object cached = this.cachedValue; + if (cached != GENERIC) { + if (cached == newValue) { + return (T) cached; + } else { + CompilerDirectives.transferToInterpreterAndInvalidate(); + if (cachedValue == UNINITIALIZED) { + cachedValue = newValue; + } else { + cachedValue = GENERIC; + } + } + } + return newValue; + } + + public boolean isGeneric() { + return getCachedValue() == GENERIC; + } + + public boolean isUninitialized() { + return getCachedValue() == UNINITIALIZED; + } + + public Object getCachedValue() { + return cachedValue; + } + + @Override + public String toString() { + return toString(ValueProfile.class, isUninitialized(), isGeneric(), // + String.format("value == %s@%x", cachedValue != null ? cachedValue.getClass().getSimpleName() : "null", Objects.hash(cachedValue))); + } + + /* Needed for lazy class loading. */ + static ValueProfile create() { + return new Identity(); + } + + } + + static final class ExactClass extends ValueProfile { + + @CompilationFinal protected Class<?> cachedClass; + + ExactClass() { + } + + public static ValueProfile create() { + return new ExactClass(); + } + + @SuppressWarnings("unchecked") + @Override + public <T> T profile(T value) { + // Field needs to be cached in local variable for thread safety and startup speed. + Class<?> clazz = cachedClass; + if (clazz != Object.class) { + if (clazz != null && value != null && clazz == value.getClass()) { + /* + * The cast is really only for the compiler relevant. It does not perform any + * useful action in the interpreter and only takes time. + */ + if (CompilerDirectives.inInterpreter()) { + return value; + } else { + return (T) clazz.cast(value); + } + } else { + CompilerDirectives.transferToInterpreterAndInvalidate(); + if (clazz == null && value != null) { + cachedClass = value.getClass(); + } else { + cachedClass = Object.class; + } + } + } + return value; + } + + boolean isGeneric() { + return cachedClass == Object.class; + } + + boolean isUninitialized() { + return cachedClass == null; + } + + Class<?> getCachedClass() { + return cachedClass; + } + + @Override + public String toString() { + return toString(ValueProfile.class, cachedClass == null, cachedClass == Object.class, // + String.format("value.getClass() == %s.class", cachedClass != null ? cachedClass.getSimpleName() : "null")); + } + + } + +}