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*
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* 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.
*
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package org.graalvm.compiler.nodes;
import java.util.Arrays;
import org.graalvm.compiler.core.common.type.TypeReference;
import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.JavaTypeProfile;
import jdk.vm.ci.meta.JavaTypeProfile.ProfiledType;
import jdk.vm.ci.meta.ResolvedJavaType;
Utility for deriving hint types for a type check instruction (e.g. checkcast or instanceof) based
on the target type of the check and any profiling information available for the instruction.
/**
* Utility for deriving hint types for a type check instruction (e.g. checkcast or instanceof) based
* on the target type of the check and any profiling information available for the instruction.
*/
public class TypeCheckHints {
A receiver type profiled in a type check instruction.
/**
* A receiver type profiled in a type check instruction.
*/
public static class Hint {
A type seen while profiling a type check instruction.
/**
* A type seen while profiling a type check instruction.
*/
public final ResolvedJavaType type;
Specifies if type is a sub-type of the checked type. /**
* Specifies if {@link #type} is a sub-type of the checked type.
*/
public final boolean positive;
Hint(ResolvedJavaType type, boolean positive) {
this.type = type;
this.positive = positive;
}
}
private static final Hint[] NO_HINTS = {};
If non-null, then this is the only type that could pass the type check because the target of
the type check is a final class or has been speculated to be a final class and this value is
the only concrete subclass of the target type.
/**
* If non-null, then this is the only type that could pass the type check because the target of
* the type check is a final class or has been speculated to be a final class and this value is
* the only concrete subclass of the target type.
*/
public final ResolvedJavaType exact;
The most likely types that the type check instruction will see.
/**
* The most likely types that the type check instruction will see.
*/
public final Hint[] hints;
The profile from which this information was derived.
/**
* The profile from which this information was derived.
*/
public final JavaTypeProfile profile;
The total probability that the type check will hit one of the types in hints. /**
* The total probability that the type check will hit one of the types in {@link #hints}.
*/
public final double hintHitProbability;
Derives hint information for use when generating the code for a type check instruction.
Params: - targetType – the target type of the type check
- profile – the profiling information available for the instruction (if any)
- assumptions – the object in which speculations are recorded. This is null if
speculations are not supported.
- minHintHitProbability – if the probability that the type check will hit one of the profiled types (up to
maxHints) is below this value, then hints will be null - maxHints – the maximum length of
hints
/**
* Derives hint information for use when generating the code for a type check instruction.
*
* @param targetType the target type of the type check
* @param profile the profiling information available for the instruction (if any)
* @param assumptions the object in which speculations are recorded. This is null if
* speculations are not supported.
* @param minHintHitProbability if the probability that the type check will hit one of the
* profiled types (up to {@code maxHints}) is below this value, then {@link #hints}
* will be null
* @param maxHints the maximum length of {@link #hints}
*/
public TypeCheckHints(TypeReference targetType, JavaTypeProfile profile, Assumptions assumptions, double minHintHitProbability, int maxHints) {
this.profile = profile;
if (targetType != null && targetType.isExact()) {
exact = targetType.getType();
} else {
exact = null;
}
Double[] hitProbability = {null};
this.hints = makeHints(targetType, profile, minHintHitProbability, maxHints, hitProbability);
this.hintHitProbability = hitProbability[0];
}
private static Hint[] makeHints(TypeReference targetType, JavaTypeProfile profile, double minHintHitProbability, int maxHints, Double[] hitProbability) {
double hitProb = 0.0d;
Hint[] hintsBuf = NO_HINTS;
if (profile != null) {
double notRecordedTypes = profile.getNotRecordedProbability();
ProfiledType[] ptypes = profile.getTypes();
if (notRecordedTypes < (1D - minHintHitProbability) && ptypes != null && ptypes.length > 0) {
hintsBuf = new Hint[ptypes.length];
int hintCount = 0;
for (ProfiledType ptype : ptypes) {
if (targetType != null) {
ResolvedJavaType hintType = ptype.getType();
hintsBuf[hintCount++] = new Hint(hintType, targetType.getType().isAssignableFrom(hintType));
hitProb += ptype.getProbability();
}
if (hintCount == maxHints) {
break;
}
}
if (hitProb >= minHintHitProbability) {
if (hintsBuf.length != hintCount || hintCount > maxHints) {
hintsBuf = Arrays.copyOf(hintsBuf, Math.min(maxHints, hintCount));
}
} else {
hintsBuf = NO_HINTS;
hitProb = 0.0d;
}
}
}
hitProbability[0] = hitProb;
return hintsBuf;
}
}