com.oracle.truffle.api.profiles.IntValueProfile Maven / Gradle / Ivy
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/*
* Copyright (c) 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
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*/
package com.oracle.truffle.api.profiles;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
/**
*
* Specialized value profile to capture certain properties of int
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
* values are profiled within a single profile then the profile has no effect. If the value
* assumption is invalidated in compiled code then it is invalidated.
*
*
*
* Usage example:
*
*
* class SampleNode extends Node {
*
* final IntValueProfile profile = IntValueProfile.createIdentityProfile();
*
* int execute(int input) {
* int profiledValue = profile.profile(input);
* // compiler may know now more about profiledValue
* return profiledValue;
* }
* }
*
*
*
*
* {@inheritDoc}
*
* @see #createIdentityProfile()
* @see ValueProfile
* @since 0.10
*/
public abstract class IntValueProfile extends Profile {
IntValueProfile() {
}
/** @since 0.10 */
public abstract int profile(int value);
/**
* Returns a value profile that profiles the exact value of an int
.
*
* @see IntValueProfile
* @since 0.10
*/
public static IntValueProfile createIdentityProfile() {
if (Profile.isProfilingEnabled()) {
return Enabled.create();
} else {
return Disabled.INSTANCE;
}
}
static final class Enabled extends IntValueProfile {
private static final byte UNINITIALIZED = 0;
private static final byte SPECIALIZED = 1;
private static final byte GENERIC = 2;
@CompilationFinal private int cachedValue;
@CompilationFinal private byte state = 0;
@Override
public int profile(int value) {
byte localState = this.state;
if (localState != GENERIC) {
if (localState == SPECIALIZED) {
int v = cachedValue;
if (v == value) {
return v;
}
}
CompilerDirectives.transferToInterpreterAndInvalidate();
if (localState == UNINITIALIZED) {
this.cachedValue = value;
this.state = SPECIALIZED;
} else {
this.state = GENERIC;
}
}
return value;
}
boolean isGeneric() {
return state == GENERIC;
}
boolean isUninitialized() {
return state == UNINITIALIZED;
}
int getCachedValue() {
return cachedValue;
}
@Override
public String toString() {
return toString(IntValueProfile.class, isUninitialized(), isGeneric(), //
String.format("value == (int)%s", cachedValue));
}
/* Needed for lazy class loading. */
static IntValueProfile create() {
return new Enabled();
}
}
static final class Disabled extends IntValueProfile {
static final IntValueProfile INSTANCE = new Disabled();
@Override
protected Object clone() {
return INSTANCE;
}
@Override
public int profile(int value) {
return value;
}
@Override
public String toString() {
return toStringDisabled(IntValueProfile.class);
}
}
}