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Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
* Subject to the condition set forth below, permission is hereby granted to any
* person obtaining a copy of this software, associated documentation and/or
* data (collectively the "Software"), free of charge and under any and all
* copyright rights in the Software, and any and all patent rights owned or
* freely licensable by each licensor hereunder covering either (i) the
* unmodified Software as contributed to or provided by such licensor, or (ii)
* the Larger Works (as defined below), to deal in both
*
* (a) the Software, and
*
* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
* one is included with the Software each a "Larger Work" to which the Software
* is contributed by such licensors),
*
* without restriction, including without limitation the rights to copy, create
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* Software and the Larger Work(s), and to sublicense the foregoing rights on
* either these or other terms.
*
* This license is subject to the following condition:
*
* The above copyright notice and either this complete permission notice or at a
* minimum a reference to the UPL must be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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*/
package com.oracle.truffle.api.profiles;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
/**
*
* ConditionProfiles are useful to profile the outcome of conditions.
*
*
*
* Usage example:
*
*
* class AbsoluteNode extends Node {
*
* final ConditionProfile greaterZeroProfile = ConditionProfile.create{Binary,Counting}Profile();
*
* void execute(int value) {
* if (greaterZeroProfile.profile(value >= 0)) {
* return value;
* } else {
* return -value;
* }
* }
* }
*
*
* {@inheritDoc}
*
* @see #createBinaryProfile()
* @see #createCountingProfile()
* @see LoopConditionProfile
* @since 0.10
*/
public abstract class ConditionProfile extends Profile {
ConditionProfile() {
}
/** @since 0.10 */
public abstract boolean profile(boolean value);
/**
* Returns a {@link ConditionProfile} that speculates on conditions to be never
* true or to be never false. Additionally to a binary profile this
* method returns a condition profile that also counts the number of times the condition was
* true and false. This information is reported to the underlying optimization system using
* {@link CompilerDirectives#injectBranchProbability(double, boolean)}. Condition profiles are
* intended to be used as part of if conditions.
*
* @see ConditionProfile
* @see #createBinaryProfile()
* @since 0.10
*/
public static ConditionProfile createCountingProfile() {
if (Profile.isProfilingEnabled()) {
return Counting.createLazyLoadClass();
} else {
return Disabled.INSTANCE;
}
}
/**
* Returns a {@link ConditionProfile} that speculates on conditions to be never
* true or to be never false. Condition profiles are intended to be
* used as part of if conditions.
*
* @see ConditionProfile
* @see ConditionProfile#createCountingProfile()
* @since 0.10
*/
public static ConditionProfile createBinaryProfile() {
if (Profile.isProfilingEnabled()) {
return Binary.createLazyLoadClass();
} else {
return Disabled.INSTANCE;
}
}
/**
* Creates a binary ConditionProfile using {@link #createBinaryProfile()}. This is a convenience
* method so it can be used as {@code @Cached ConditionProfile myProfile} instead of the much
* longer {@code @Cached("createBinaryProfile()") ConditionProfile myProfile}.
*
* @since 20.2
*/
public static ConditionProfile create() {
return createBinaryProfile();
}
/**
* Returns the uncached version of the profile. The uncached version of a profile does nothing.
*
* @since 19.0
*/
public static ConditionProfile getUncached() {
return Disabled.INSTANCE;
}
static final class Disabled extends ConditionProfile {
static final ConditionProfile INSTANCE = new Disabled();
@Override
protected Object clone() {
return INSTANCE;
}
@Override
public boolean profile(boolean value) {
return value;
}
@Override
public String toString() {
return toStringDisabled(ConditionProfile.class);
}
}
static final class Counting extends ConditionProfile {
@CompilationFinal private int trueCount;
@CompilationFinal private int falseCount;
/**
* A constant holding the maximum value an {@code int} can have, 230-1. The sum
* of the true and false count must not overflow. This constant is used to check whether one
* of the counts does not exceed the required maximum value.
*/
public static final int MAX_VALUE = 0x3fffffff;
Counting() {
}
@Override
public boolean profile(boolean value) {
// locals required to guarantee no overflow in multi-threaded environments
int t = trueCount;
int f = falseCount;
boolean val = value;
if (val) {
if (t == 0) {
CompilerDirectives.transferToInterpreterAndInvalidate();
}
if (f == 0) {
// Make this branch fold during PE
val = true;
}
if (CompilerDirectives.inInterpreter()) {
if (t < MAX_VALUE) {
trueCount = t + 1;
}
}
} else {
if (f == 0) {
CompilerDirectives.transferToInterpreterAndInvalidate();
}
if (t == 0) {
// Make this branch fold during PE
val = false;
}
if (CompilerDirectives.inInterpreter()) {
if (f < MAX_VALUE) {
falseCount = f + 1;
}
}
}
if (CompilerDirectives.inInterpreter()) {
// no branch probability calculation in the interpreter
return val;
} else {
int sum = t + f;
return CompilerDirectives.injectBranchProbability((double) t / (double) sum, val);
}
}
int getTrueCount() {
return trueCount;
}
int getFalseCount() {
return falseCount;
}
@Override
public String toString() {
int t = trueCount;
int f = falseCount;
int sum = t + f;
String details = String.format("trueProbability=%s (trueCount=%s, falseCount=%s)", (double) t / (double) sum, t, f);
return toString(ConditionProfile.class, sum == 0, false, details);
}
/* Needed for lazy class loading. */
static ConditionProfile createLazyLoadClass() {
return new Counting();
}
}
/**
* Utility class to speculate on conditions to be never true or to be never false. Condition
* profiles are intended to be used as part of if conditions.
*
* @see ConditionProfile#createBinaryProfile()
*/
static final class Binary extends ConditionProfile {
@CompilationFinal private boolean wasTrue;
@CompilationFinal private boolean wasFalse;
Binary() {
}
@Override
public boolean profile(boolean value) {
if (value) {
if (!wasTrue) {
CompilerDirectives.transferToInterpreterAndInvalidate();
wasTrue = true;
}
return true;
} else {
if (!wasFalse) {
CompilerDirectives.transferToInterpreterAndInvalidate();
wasFalse = true;
}
return false;
}
}
boolean wasTrue() {
return wasTrue;
}
boolean wasFalse() {
return wasFalse;
}
@Override
public String toString() {
return String.format("%s(wasTrue=%s, wasFalse=%s)@%x", getClass().getSimpleName(), wasTrue, wasFalse, hashCode());
}
/* Needed for lazy class loading. */
static ConditionProfile createLazyLoadClass() {
return new Binary();
}
}
}