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 * This code is distributed in the hope that it will be useful, but WITHOUT

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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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.vm.ci.meta;

import java.util.ArrayList;

import jdk.vm.ci.meta.JavaTypeProfile.ProfiledType;

/**

 * This profile object represents the type profile at a specific BCI. The precision of the supplied

 * values may vary, but a runtime that provides this information should be aware that it will be

 * used to guide performance-critical decisions like speculative inlining, etc.

 */

public final class JavaTypeProfile extends AbstractJavaProfile<ProfiledType, ResolvedJavaType> {

    private static final ProfiledType[] EMPTY_ARRAY = new ProfiledType[0];

    private final TriState nullSeen;

    public JavaTypeProfile(TriState nullSeen, double notRecordedProbability, ProfiledType[] pitems) {

        super(notRecordedProbability, pitems);

        this.nullSeen = nullSeen;

    }

    /**

     * Returns whether a null value was at the type check.

     */

    public TriState getNullSeen() {

        return nullSeen;

    }

    /**

     * A list of types for which the runtime has recorded probability information. Note that this

     * includes both positive and negative types where a positive type is a subtype of the checked

     * type and a negative type is not.

     */

    public ProfiledType[] getTypes() {

        return getItems();

    }

    public JavaTypeProfile restrict(JavaTypeProfile otherProfile) {

        if (otherProfile.getNotRecordedProbability() > 0.0) {

            // Not useful for restricting since there is an unknown set of types occurring.

            return this;

        }

        if (this.getNotRecordedProbability() > 0.0) {

            // We are unrestricted, so the other profile is always a better estimate.

            return otherProfile;

        }

        ArrayList<ProfiledType> result = new ArrayList<>();

        for (int i = 0; i < getItems().length; i++) {

            ProfiledType ptype = getItems()[i];

            ResolvedJavaType type = ptype.getItem();

            if (otherProfile.isIncluded(type)) {

                result.add(ptype);

            }

        }

        TriState newNullSeen = (otherProfile.getNullSeen() == TriState.FALSE) ? TriState.FALSE : getNullSeen();

        double newNotRecorded = getNotRecordedProbability();

        return createAdjustedProfile(result, newNullSeen, newNotRecorded);

    }

    public JavaTypeProfile restrict(ResolvedJavaType declaredType, boolean nonNull) {

        ArrayList<ProfiledType> result = new ArrayList<>();

        for (int i = 0; i < getItems().length; i++) {

            ProfiledType ptype = getItems()[i];

            ResolvedJavaType type = ptype.getItem();

            if (declaredType.isAssignableFrom(type)) {

                result.add(ptype);

            }

        }

        TriState newNullSeen = (nonNull) ? TriState.FALSE : getNullSeen();

        double newNotRecorded = this.getNotRecordedProbability();

        // Assume for the types not recorded, the incompatibility rate is the same.

        if (getItems().length != 0) {

            newNotRecorded *= ((double) result.size() / (double) getItems().length);

        }

        return createAdjustedProfile(result, newNullSeen, newNotRecorded);

    }

    private JavaTypeProfile createAdjustedProfile(ArrayList<ProfiledType> result, TriState newNullSeen, double newNotRecorded) {

        if (result.size() != this.getItems().length || newNotRecorded != getNotRecordedProbability() || newNullSeen != getNullSeen()) {

            if (result.size() == 0) {

                return new JavaTypeProfile(newNullSeen, 1.0, EMPTY_ARRAY);

            }

            double factor;

            if (result.size() == this.getItems().length) {

                /* List of types did not change, no need to recompute probabilities. */

                factor = 1.0;

            } else {

                double probabilitySum = 0.0;

                for (int i = 0; i < result.size(); i++) {

                    probabilitySum += result.get(i).getProbability();

                }

                probabilitySum += newNotRecorded;

                factor = 1.0 / probabilitySum; // Normalize to 1.0

                assert factor >= 1.0;

            }

            ProfiledType[] newResult = new ProfiledType[result.size()];

            for (int i = 0; i < newResult.length; ++i) {

                ProfiledType curType = result.get(i);

                newResult[i] = new ProfiledType(curType.getItem(), Math.min(1.0, curType.getProbability() * factor));

            }

            double newNotRecordedTypeProbability = Math.min(1.0, newNotRecorded * factor);

            return new JavaTypeProfile(newNullSeen, newNotRecordedTypeProbability, newResult);

        }

        return this;

    }

    @Override

    public boolean equals(Object other) {

        return super.equals(other) && nullSeen.equals(((JavaTypeProfile) other).nullSeen);

    }

    @Override

    public int hashCode() {

        return nullSeen.hashCode() + super.hashCode();

    }

    public static class ProfiledType extends AbstractProfiledItem<ResolvedJavaType> {

        public ProfiledType(ResolvedJavaType type, double probability) {

            super(type, probability);

        }

        /**

         * Returns the type for this profile entry.

         */

        public ResolvedJavaType getType() {

            return getItem();

        }

        @Override

        public String toString() {

            return String.format("%.6f#%s", probability, item);

        }

    }

    @Override

    public String toString() {

        StringBuilder buf = new StringBuilder("JavaTypeProfile<nullSeen=").append(getNullSeen()).append(", types=[");

        for (int j = 0; j < getTypes().length; j++) {

            if (j != 0) {

                buf.append(", ");

            }

            ProfiledType ptype = getTypes()[j];

            buf.append(String.format("%.6f:%s", ptype.getProbability(), ptype.getType()));

        }

        return buf.append(String.format("], notRecorded:%.6f>", getNotRecordedProbability())).toString();

    }

    /**

     * Returns {@code true} if all types seen at this location have been recorded in the profile.

     */

    public boolean allTypesRecorded() {

        return this.getNotRecordedProbability() == 0.0;

    }

    /**

     * Returns the single monormorphic type representing this profile or {@code null} if no such

     * type exists.

     */

    public ResolvedJavaType asSingleType() {

        if (allTypesRecorded() && this.getTypes().length == 1) {

            return getTypes()[0].getType();

        }

        return null;

    }

}