--- /dev/null 2016-05-31 09:42:47.975716356 -0700 +++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/type/AbstractObjectStamp.java 2016-12-09 00:47:13.825341495 -0800 @@ -0,0 +1,338 @@ +/* + * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * 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 + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package org.graalvm.compiler.core.common.type; + +import java.util.AbstractList; +import java.util.Objects; +import java.util.RandomAccess; + +import jdk.vm.ci.meta.Constant; +import jdk.vm.ci.meta.JavaConstant; +import jdk.vm.ci.meta.JavaKind; +import jdk.vm.ci.meta.MetaAccessProvider; +import jdk.vm.ci.meta.ResolvedJavaType; + +/** + * Type describing all pointers to Java objects. + */ +public abstract class AbstractObjectStamp extends AbstractPointerStamp { + + private final ResolvedJavaType type; + private final boolean exactType; + + protected AbstractObjectStamp(ResolvedJavaType type, boolean exactType, boolean nonNull, boolean alwaysNull) { + super(nonNull, alwaysNull); + this.type = type; + this.exactType = exactType; + } + + protected abstract AbstractObjectStamp copyWith(ResolvedJavaType newType, boolean newExactType, boolean newNonNull, boolean newAlwaysNull); + + @Override + protected final AbstractPointerStamp copyWith(boolean newNonNull, boolean newAlwaysNull) { + return copyWith(type, exactType, newNonNull, newAlwaysNull); + } + + @Override + public Stamp unrestricted() { + return copyWith(null, false, false, false); + } + + @Override + public Stamp empty() { + return copyWith(null, true, true, false); + } + + @Override + public Stamp constant(Constant c, MetaAccessProvider meta) { + JavaConstant jc = (JavaConstant) c; + ResolvedJavaType constType = jc.isNull() ? null : meta.lookupJavaType(jc); + return copyWith(constType, jc.isNonNull(), jc.isNonNull(), jc.isNull()); + } + + @Override + public boolean hasValues() { + return !exactType || (type != null && (isConcreteType(type))); + } + + @Override + public JavaKind getStackKind() { + return JavaKind.Object; + } + + @Override + public ResolvedJavaType javaType(MetaAccessProvider metaAccess) { + if (type != null) { + return type; + } + return metaAccess.lookupJavaType(Object.class); + } + + public ResolvedJavaType type() { + return type; + } + + public boolean isExactType() { + return exactType && type != null; + } + + protected void appendString(StringBuilder str) { + if (this.isEmpty()) { + str.append(" empty"); + } else { + str.append(nonNull() ? "!" : "").append(exactType ? "#" : "").append(' ').append(type == null ? "-" : type.getName()).append(alwaysNull() ? " NULL" : ""); + } + } + + @Override + public Stamp meet(Stamp otherStamp) { + if (this == otherStamp) { + return this; + } + AbstractObjectStamp other = (AbstractObjectStamp) otherStamp; + if (isEmpty()) { + return other; + } else if (other.isEmpty()) { + return this; + } + ResolvedJavaType meetType; + boolean meetExactType; + boolean meetNonNull; + boolean meetAlwaysNull; + if (other.alwaysNull()) { + meetType = type(); + meetExactType = exactType; + meetNonNull = false; + meetAlwaysNull = alwaysNull(); + } else if (alwaysNull()) { + meetType = other.type(); + meetExactType = other.exactType; + meetNonNull = false; + meetAlwaysNull = other.alwaysNull(); + } else { + meetType = meetTypes(type(), other.type()); + meetExactType = exactType && other.exactType; + if (meetExactType && type != null && other.type != null) { + // meeting two valid exact types may result in a non-exact type + meetExactType = Objects.equals(meetType, type) && Objects.equals(meetType, other.type); + } + meetNonNull = nonNull() && other.nonNull(); + meetAlwaysNull = false; + } + + if (Objects.equals(meetType, type) && meetExactType == exactType && meetNonNull == nonNull() && meetAlwaysNull == alwaysNull()) { + return this; + } else if (Objects.equals(meetType, other.type) && meetExactType == other.exactType && meetNonNull == other.nonNull() && meetAlwaysNull == other.alwaysNull()) { + return other; + } else { + return copyWith(meetType, meetExactType, meetNonNull, meetAlwaysNull); + } + } + + @Override + public Stamp join(Stamp otherStamp) { + return join0(otherStamp, false); + } + + /** + * Returns the stamp representing the type of this stamp after a cast to the type represented by + * the {@code to} stamp. While this is very similar to a {@link #join} operation, in the case + * where both types are not obviously related, the cast operation will prefer the type of the + * {@code to} stamp. This is necessary as long as ObjectStamps are not able to accurately + * represent intersection types. + * + * For example when joining the {@link RandomAccess} type with the {@link AbstractList} type, + * without intersection types, this would result in the most generic type ({@link Object} ). For + * this reason, in some cases a {@code castTo} operation is preferable in order to keep at least + * the {@link AbstractList} type. + * + * @param other the stamp this stamp should be casted to + * @return the new improved stamp or {@code null} if this stamp cannot be improved + */ + @Override + public Stamp improveWith(Stamp other) { + return join0(other, true); + } + + private Stamp join0(Stamp otherStamp, boolean improve) { + if (this == otherStamp) { + return this; + } + AbstractObjectStamp other = (AbstractObjectStamp) otherStamp; + if (isEmpty()) { + return this; + } else if (other.isEmpty()) { + return other; + } + + ResolvedJavaType joinType; + boolean joinAlwaysNull = alwaysNull() || other.alwaysNull(); + boolean joinNonNull = nonNull() || other.nonNull(); + boolean joinExactType = exactType || other.exactType; + if (Objects.equals(type, other.type)) { + joinType = type; + } else if (type == null && other.type == null) { + joinType = null; + } else if (type == null) { + joinType = other.type; + } else if (other.type == null) { + joinType = type; + } else { + // both types are != null and different + if (type.isAssignableFrom(other.type)) { + joinType = other.type; + if (exactType) { + joinAlwaysNull = true; + } + } else if (other.type.isAssignableFrom(type)) { + joinType = type; + if (other.exactType) { + joinAlwaysNull = true; + } + } else { + if (improve) { + joinType = type; + joinExactType = exactType; + } else { + joinType = null; + } + + if (joinExactType || (!isInterfaceOrArrayOfInterface(type) && !isInterfaceOrArrayOfInterface(other.type))) { + joinAlwaysNull = true; + } + } + } + if (joinAlwaysNull) { + joinType = null; + joinExactType = false; + } + if (joinExactType && joinType == null) { + return empty(); + } + if (joinAlwaysNull && joinNonNull) { + return empty(); + } else if (joinExactType && !isConcreteType(joinType)) { + return empty(); + } + if (Objects.equals(joinType, type) && joinExactType == exactType && joinNonNull == nonNull() && joinAlwaysNull == alwaysNull()) { + return this; + } else if (Objects.equals(joinType, other.type) && joinExactType == other.exactType && joinNonNull == other.nonNull() && joinAlwaysNull == other.alwaysNull()) { + return other; + } else { + return copyWith(joinType, joinExactType, joinNonNull, joinAlwaysNull); + } + } + + private static boolean isInterfaceOrArrayOfInterface(ResolvedJavaType t) { + return t.isInterface() || (t.isArray() && t.getElementalType().isInterface()); + } + + public static boolean isConcreteType(ResolvedJavaType type) { + return !(type.isAbstract() && !type.isArray()); + } + + private static ResolvedJavaType meetTypes(ResolvedJavaType a, ResolvedJavaType b) { + if (Objects.equals(a, b)) { + return a; + } else if (a == null || b == null) { + return null; + } else { + // The `meetTypes` operation must be commutative. One way to achieve this is to totally + // order the types and always call `meetOrderedNonNullTypes` in the same order. We + // establish the order by first comparing the hash-codes for performance reasons, and + // then comparing the internal names of the types. + int hashA = a.getName().hashCode(); + int hashB = b.getName().hashCode(); + if (hashA < hashB) { + return meetOrderedNonNullTypes(a, b); + } else if (hashB < hashA) { + return meetOrderedNonNullTypes(b, a); + } else { + int diff = a.getName().compareTo(b.getName()); + if (diff <= 0) { + return meetOrderedNonNullTypes(a, b); + } else { + return meetOrderedNonNullTypes(b, a); + } + } + } + } + + private static ResolvedJavaType meetOrderedNonNullTypes(ResolvedJavaType a, ResolvedJavaType b) { + ResolvedJavaType result = a.findLeastCommonAncestor(b); + if (result.isJavaLangObject() && a.isInterface() && b.isInterface()) { + // Both types are incompatible interfaces => search for first possible common + // ancestor match among super interfaces. + ResolvedJavaType[] interfacesA = a.getInterfaces(); + ResolvedJavaType[] interfacesB = b.getInterfaces(); + for (int i = 0; i < interfacesA.length; ++i) { + ResolvedJavaType interface1 = interfacesA[i]; + for (int j = 0; j < interfacesB.length; ++j) { + ResolvedJavaType interface2 = interfacesB[j]; + ResolvedJavaType leastCommon = meetTypes(interface1, interface2); + if (leastCommon.isInterface()) { + return leastCommon; + } + } + } + } + return result; + } + + @Override + public int hashCode() { + final int prime = 31; + int result = 1; + result = prime * result + super.hashCode(); + result = prime * result + (exactType ? 1231 : 1237); + result = prime * result + ((type == null || type.isJavaLangObject()) ? 0 : type.hashCode()); + return result; + } + + @Override + public boolean equals(Object obj) { + if (this == obj) { + return true; + } + if (obj == null || getClass() != obj.getClass()) { + return false; + } + AbstractObjectStamp other = (AbstractObjectStamp) obj; + if (exactType != other.exactType) { + return false; + } + // null == java.lang.Object + if (type == null) { + if (other.type != null && !other.type.isJavaLangObject()) { + return false; + } + } else if (other.type == null) { + if (type != null && !type.isJavaLangObject()) { + return false; + } + } else if (!type.equals(other.type)) { + return false; + } + return super.equals(other); + } +}