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*
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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 long 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 LongValueProfile profile = LongValueProfile.createIdentityProfile();
*
* long execute(long input) {
* long profiledValue = profile.profile(input);
* // compiler may know now more about profiledValue
* return profiledValue;
* }
* }
*
*
*
* {@inheritDoc}
*
* @see #createIdentityProfile()
* @see ValueProfile
* @since 0.10
*/
public abstract class LongValueProfile extends Profile {
LongValueProfile() {
}
/** @since 0.10 */
public abstract long profile(long value);
/**
* Returns a value profile that profiles the exact value of an long.
*
* @see LongValueProfile
* @since 0.10
*/
public static LongValueProfile createIdentityProfile() {
if (Profile.isProfilingEnabled()) {
return Enabled.create();
} else {
return Disabled.INSTANCE;
}
}
/**
* Returns the uncached version of the profile. The uncached version of a profile does nothing.
*
* @since 19.0
*/
public static LongValueProfile getUncached() {
return Disabled.INSTANCE;
}
static final class Enabled extends LongValueProfile {
private static final byte UNINITIALIZED = 0;
private static final byte SPECIALIZED = 1;
private static final byte GENERIC = 2;
@CompilationFinal private long cachedValue;
@CompilationFinal private byte state = UNINITIALIZED;
@Override
public long profile(long value) {
byte localState = this.state;
if (localState != GENERIC) {
if (localState == SPECIALIZED) {
long 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;
}
@Override
public void disable() {
this.state = GENERIC;
}
@Override
public void reset() {
this.state = UNINITIALIZED;
}
long getCachedValue() {
return cachedValue;
}
@Override
public String toString() {
return toString(LongValueProfile.class, state == UNINITIALIZED, state == GENERIC, //
String.format("value == (long)%s", cachedValue));
}
/* Needed for lazy class loading. */
static LongValueProfile create() {
return new Enabled();
}
}
static final class Disabled extends LongValueProfile {
static final LongValueProfile INSTANCE = new Disabled();
@Override
protected Object clone() {
return INSTANCE;
}
@Override
public long profile(long value) {
return value;
}
@Override
public String toString() {
return toStringDisabled(LongValueProfile.class);
}
}
}