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package com.oracle.truffle.api.profiles;
import java.util.Objects;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
Specialized value profile to capture certain properties of Object 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 boolean, byte, int, long, float and double values.
Usage example:
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;
}
}
{@inheritDoc}
See Also: Since: 0.10
/**
* <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()
* @since 0.10
*/
public abstract class ValueProfile extends Profile {
ValueProfile() {
}
Since: 0.10
/** @since 0.10 */
public abstract <T> T profile(T value);
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 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.
Compilation notes: 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.
See Also: Since: 0.10
/**
* <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
* @since 0.10
*/
public static ValueProfile createClassProfile() {
if (Profile.isProfilingEnabled()) {
return ExactClass.create();
} else {
return Disabled.INSTANCE;
}
}
Returns a value profile that profiles the object identity of a value. A single instance can
only profile one particular instance.
Compilation notes: 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.
Since: 0.10
/**
* <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>
*
* @since 0.10
*/
public static ValueProfile createIdentityProfile() {
if (Profile.isProfilingEnabled()) {
return Identity.create();
} else {
return Disabled.INSTANCE;
}
}
Returns a value profile that profiles the object equality of a value. A single instance can
only profile one set of equal values.
Compilation notes: 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.
Since: 0.10
/**
* <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>
*
* @since 0.10
*/
public static ValueProfile createEqualityProfile() {
if (Profile.isProfilingEnabled()) {
return Equality.create();
} else {
return Disabled.INSTANCE;
}
}
Returns the uncached version of the profile. The uncached version of a profile does nothing.
Since: 19.0
/**
* Returns the uncached version of the profile. The uncached version of a profile does nothing.
*
* @since 19.0
*/
public static ValueProfile getUncached() {
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 && value.getClass() == clazz) {
if (CompilerDirectives.inInterpreter()) {
return value;
} else {
return (T) CompilerDirectives.castExact(value, clazz);
}
} 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"));
}
}
}