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Diffstat (limited to 'src/proguard/evaluation/value/TypedReferenceValue.java')
| -rw-r--r-- | src/proguard/evaluation/value/TypedReferenceValue.java | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/src/proguard/evaluation/value/TypedReferenceValue.java b/src/proguard/evaluation/value/TypedReferenceValue.java new file mode 100644 index 0000000..4f8629c --- /dev/null +++ b/src/proguard/evaluation/value/TypedReferenceValue.java @@ -0,0 +1,613 @@ +/* + * ProGuard -- shrinking, optimization, obfuscation, and preverification + * of Java bytecode. + * + * Copyright (c) 2002-2014 Eric Lafortune (eric@graphics.cornell.edu) + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + * This program 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 for + * more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +package proguard.evaluation.value; + +import proguard.classfile.*; +import proguard.classfile.util.ClassUtil; +import proguard.classfile.visitor.ClassCollector; + +import java.util.*; + +/** + * This ReferenceValue represents a partially evaluated reference value. + * It has a type and a flag that indicates whether the value could be + * <code>null</code>. If the type is <code>null</code>, the value is + * <code>null</code>. + * + * @author Eric Lafortune + */ +public class TypedReferenceValue extends ReferenceValue +{ + private static final boolean DEBUG = false; + + + protected final String type; + protected final Clazz referencedClass; + protected final boolean mayBeNull; + + + /** + * Creates a new TypedReferenceValue. + */ + public TypedReferenceValue(String type, + Clazz referencedClass, + boolean mayBeNull) + { + this.type = type; + this.referencedClass = referencedClass; + this.mayBeNull = mayBeNull; + } + + + // Implementations for ReferenceValue. + + public String getType() + { + return type; + } + + + public Clazz getReferencedClass() + { + return referencedClass; + } + + + // Implementations of unary methods of ReferenceValue. + + public int isNull() + { + return type == null ? ALWAYS : + mayBeNull ? MAYBE : + NEVER; + } + + + public int instanceOf(String otherType, Clazz otherReferencedClass) + { + String thisType = this.type; + + // If this type is null, it is never an instance of any class. + if (thisType == null) + { + return NEVER; + } + + // Start taking into account the type dimensions. + int thisDimensionCount = ClassUtil.internalArrayTypeDimensionCount(thisType); + int otherDimensionCount = ClassUtil.internalArrayTypeDimensionCount(otherType); + int commonDimensionCount = Math.min(thisDimensionCount, otherDimensionCount); + + // Strip any common array prefixes. + thisType = thisType.substring(commonDimensionCount); + otherType = otherType.substring(commonDimensionCount); + + // If either stripped type is a primitive type, we can tell right away. + if (commonDimensionCount > 0 && + (ClassUtil.isInternalPrimitiveType(thisType.charAt(0)) || + ClassUtil.isInternalPrimitiveType(otherType.charAt(0)))) + { + return !thisType.equals(otherType) ? NEVER : + mayBeNull ? MAYBE : + ALWAYS; + } + + // Strip the class type prefix and suffix of this type, if any. + if (thisDimensionCount == commonDimensionCount) + { + thisType = ClassUtil.internalClassNameFromClassType(thisType); + } + + // Strip the class type prefix and suffix of the other type, if any. + if (otherDimensionCount == commonDimensionCount) + { + otherType = ClassUtil.internalClassNameFromClassType(otherType); + } + + // If this type is an array type, and the other type is not + // java.lang.Object, java.lang.Cloneable, or java.io.Serializable, + // this type can never be an instance. + if (thisDimensionCount > otherDimensionCount && + !ClassUtil.isInternalArrayInterfaceName(otherType)) + { + return NEVER; + } + + // If the other type is an array type, and this type is not + // java.lang.Object, java.lang.Cloneable, or java.io.Serializable, + // this type can never be an instance. + if (thisDimensionCount < otherDimensionCount && + !ClassUtil.isInternalArrayInterfaceName(thisType)) + { + return NEVER; + } + + // If this type may be null, it might not be an instance of any class. + if (mayBeNull) + { + return MAYBE; + } + + // If this type is equal to the other type, or if the other type is + // java.lang.Object, this type is always an instance. + if (thisType.equals(otherType) || + ClassConstants.NAME_JAVA_LANG_OBJECT.equals(otherType)) + { + return ALWAYS; + } + + // If this type is an array type, it's ok. + if (thisDimensionCount > otherDimensionCount) + { + return ALWAYS; + } + + // If the other type is an array type, it might be ok. + if (thisDimensionCount < otherDimensionCount) + { + return MAYBE; + } + + // If the value extends the type, we're sure. + return referencedClass != null && + otherReferencedClass != null && + referencedClass.extendsOrImplements(otherReferencedClass) ? + ALWAYS : + MAYBE; + } + + + public ReferenceValue generalizeMayBeNull(boolean mayBeNull) + { + return this.mayBeNull == mayBeNull ? + this : + new TypedReferenceValue(type, referencedClass, true); + } + + + public ReferenceValue referenceArrayLoad(IntegerValue indexValue, ValueFactory valueFactory) + { + return + type == null ? ValueFactory.REFERENCE_VALUE_NULL : + !ClassUtil.isInternalArrayType(type) ? ValueFactory.REFERENCE_VALUE_JAVA_LANG_OBJECT_MAYBE_NULL : + valueFactory.createValue(type.substring(1), + referencedClass, + true).referenceValue(); + } + + + // Implementations of binary methods of ReferenceValue. + + public ReferenceValue generalize(ReferenceValue other) + { + return other.generalize(this); + } + + + public int equal(ReferenceValue other) + { + return other.equal(this); + } + + + // Implementations of binary ReferenceValue methods with TypedReferenceValue + // arguments. + + public ReferenceValue generalize(TypedReferenceValue other) + { + // If both types are identical, the generalization is the same too. + if (this.equals(other)) + { + return this; + } + + String thisType = this.type; + String otherType = other.type; + + // If both types are nul, the generalization is null too. + if (thisType == null && otherType == null) + { + return ValueFactory.REFERENCE_VALUE_NULL; + } + + // If this type is null, the generalization is the other type, maybe null. + if (thisType == null) + { + return other.generalizeMayBeNull(true); + } + + // If the other type is null, the generalization is this type, maybe null. + if (otherType == null) + { + return this.generalizeMayBeNull(true); + } + + boolean mayBeNull = this.mayBeNull || other.mayBeNull; + + // If the two types are equal, the generalization remains the same, maybe null. + if (thisType.equals(otherType)) + { + return typedReferenceValue(this, mayBeNull); + } + + // Start taking into account the type dimensions. + int thisDimensionCount = ClassUtil.internalArrayTypeDimensionCount(thisType); + int otherDimensionCount = ClassUtil.internalArrayTypeDimensionCount(otherType); + int commonDimensionCount = Math.min(thisDimensionCount, otherDimensionCount); + + if (thisDimensionCount == otherDimensionCount) + { + // See if we can take into account the referenced classes. + Clazz thisReferencedClass = this.referencedClass; + Clazz otherReferencedClass = other.referencedClass; + + if (thisReferencedClass != null && + otherReferencedClass != null) + { + // Is one class simply an extension of the other one? + if (thisReferencedClass.extendsOrImplements(otherReferencedClass)) + { + return typedReferenceValue(other, mayBeNull); + } + + if (otherReferencedClass.extendsOrImplements(thisReferencedClass)) + { + return typedReferenceValue(this, mayBeNull); + } + + // Do the classes have a non-trivial common superclass? + Clazz commonClass = findCommonClass(thisReferencedClass, + otherReferencedClass, + false); + + if (commonClass.getName().equals(ClassConstants.NAME_JAVA_LANG_OBJECT)) + { + // Otherwise, do the classes have a common interface? + Clazz commonInterface = findCommonClass(thisReferencedClass, + otherReferencedClass, + true); + if (commonInterface != null) + { + commonClass = commonInterface; + } + } + + return new TypedReferenceValue(commonDimensionCount == 0 ? + commonClass.getName() : + ClassUtil.internalArrayTypeFromClassName(commonClass.getName(), + commonDimensionCount), + commonClass, + mayBeNull); + } + } + else if (thisDimensionCount > otherDimensionCount) + { + // See if the other type is an interface type of arrays. + if (ClassUtil.isInternalArrayInterfaceName(ClassUtil.internalClassNameFromClassType(otherType))) + { + return typedReferenceValue(other, mayBeNull); + } + } + else if (thisDimensionCount < otherDimensionCount) + { + // See if this type is an interface type of arrays. + if (ClassUtil.isInternalArrayInterfaceName(ClassUtil.internalClassNameFromClassType(thisType))) + { + return typedReferenceValue(this, mayBeNull); + } + } + + // Reduce the common dimension count if either type is an array of + // primitives type of this dimension. + if (commonDimensionCount > 0 && + (ClassUtil.isInternalPrimitiveType(otherType.charAt(commonDimensionCount))) || + ClassUtil.isInternalPrimitiveType(thisType.charAt(commonDimensionCount))) + { + commonDimensionCount--; + } + + // Fall back on a basic Object or array of Objects type. + return + commonDimensionCount != 0 ? + new TypedReferenceValue(ClassUtil.internalArrayTypeFromClassName(ClassConstants.NAME_JAVA_LANG_OBJECT, commonDimensionCount), + null, + mayBeNull) : + mayBeNull ? + ValueFactory.REFERENCE_VALUE_JAVA_LANG_OBJECT_MAYBE_NULL : + ValueFactory.REFERENCE_VALUE_JAVA_LANG_OBJECT_NOT_NULL; + } + + + /** + * Returns the most specific common superclass or interface of the given + * classes. + * @param class1 the first class. + * @param class2 the second class. + * @param interfaces specifies whether to look for a superclass or for an + * interface. + * @return the common class. + */ + private Clazz findCommonClass(Clazz class1, + Clazz class2, + boolean interfaces) + { + // Collect the superclasses or the interfaces of this class. + Set superClasses1 = new HashSet(); + class1.hierarchyAccept(!interfaces, + !interfaces, + interfaces, + false, + new ClassCollector(superClasses1)); + + int superClasses1Count = superClasses1.size(); + if (superClasses1Count == 0) + { + if (interfaces) + { + return null; + } + else if (class1.getSuperName() != null) + { + throw new IllegalArgumentException("Can't find any super classes of ["+class1.getName()+"] (not even immediate super class ["+class1.getSuperName()+"])"); + } + } + + // Collect the superclasses or the interfaces of the other class. + Set superClasses2 = new HashSet(); + class2.hierarchyAccept(!interfaces, + !interfaces, + interfaces, + false, + new ClassCollector(superClasses2)); + + int superClasses2Count = superClasses2.size(); + if (superClasses2Count == 0) + { + if (interfaces) + { + return null; + } + else if (class2.getSuperName() != null) + { + throw new IllegalArgumentException("Can't find any super classes of ["+class2.getName()+"] (not even immediate super class ["+class2.getSuperName()+"])"); + } + } + + if (DEBUG) + { + System.out.println("ReferenceValue.generalize this ["+class1.getName()+"] with other ["+class2.getName()+"] (interfaces = "+interfaces+")"); + System.out.println(" This super classes: "+superClasses1); + System.out.println(" Other super classes: "+superClasses2); + } + + // Find the common superclasses. + superClasses1.retainAll(superClasses2); + + if (DEBUG) + { + System.out.println(" Common super classes: "+superClasses1); + } + + if (interfaces && superClasses1.isEmpty()) + { + return null; + } + + // Find a class that is a subclass of all common superclasses, + // or that at least has the maximum number of common superclasses. + Clazz commonClass = null; + + int maximumSuperClassCount = -1; + + // Go over all common superclasses to find it. In case of + // multiple subclasses, keep the lowest one alphabetically, + // in order to ensure that the choice is deterministic. + Iterator commonSuperClasses = superClasses1.iterator(); + while (commonSuperClasses.hasNext()) + { + Clazz commonSuperClass = (Clazz)commonSuperClasses.next(); + + int superClassCount = superClassCount(commonSuperClass, superClasses1); + if (maximumSuperClassCount < superClassCount || + (maximumSuperClassCount == superClassCount && + commonClass != null && + commonClass.getName().compareTo(commonSuperClass.getName()) > 0)) + { + commonClass = commonSuperClass; + maximumSuperClassCount = superClassCount; + } + } + + if (commonClass == null) + { + throw new IllegalArgumentException("Can't find common super class of ["+ + class1.getName() +"] (with "+superClasses1Count +" known super classes) and ["+ + class2.getName()+"] (with "+superClasses2Count+" known super classes)"); + } + + if (DEBUG) + { + System.out.println(" Best common class: ["+commonClass.getName()+"]"); + } + + return commonClass; + } + + + /** + * Returns the given reference value that may or may not be null, ensuring + * that it is a TypedReferenceValue, not a subclass. + */ + private static ReferenceValue typedReferenceValue(TypedReferenceValue referenceValue, + boolean mayBeNull) + { + return referenceValue.getClass() == TypedReferenceValue.class ? + referenceValue.generalizeMayBeNull(mayBeNull) : + new TypedReferenceValue(referenceValue.type, + referenceValue.referencedClass, + mayBeNull); + } + + + /** + * Returns if the number of superclasses of the given class in the given + * set of classes. + */ + private int superClassCount(Clazz subClass, Set classes) + { + int count = 0; + + Iterator iterator = classes.iterator(); + + while (iterator.hasNext()) + { + Clazz clazz = (Clazz)iterator.next(); + if (subClass.extendsOrImplements(clazz)) + { + count++; + } + } + + return count; + } + + + public int equal(TypedReferenceValue other) + { + return this.type == null && other.type == null ? ALWAYS : MAYBE; + } + + + // Implementations of binary ReferenceValue methods with + // IdentifiedReferenceValue arguments. + + public ReferenceValue generalize(IdentifiedReferenceValue other) + { + return generalize((TypedReferenceValue)other); + } + + + public int equal(IdentifiedReferenceValue other) + { + return equal((TypedReferenceValue)other); + } + + + // Implementations of binary ReferenceValue methods with + // ArrayReferenceValue arguments. + + public ReferenceValue generalize(ArrayReferenceValue other) + { + return generalize((TypedReferenceValue)other); + } + + + public int equal(ArrayReferenceValue other) + { + return equal((TypedReferenceValue)other); + } + + + // Implementations of binary ReferenceValue methods with + // IdentifiedArrayReferenceValue arguments. + + public ReferenceValue generalize(IdentifiedArrayReferenceValue other) + { + return generalize((ArrayReferenceValue)other); + } + + + public int equal(IdentifiedArrayReferenceValue other) + { + return equal((ArrayReferenceValue)other); + } + + + // Implementations of binary ReferenceValue methods with + // DetailedArrayReferenceValue arguments. + + public ReferenceValue generalize(DetailedArrayReferenceValue other) + { + return generalize((IdentifiedArrayReferenceValue)other); + } + + + public int equal(DetailedArrayReferenceValue other) + { + return equal((IdentifiedArrayReferenceValue)other); + } + + + // Implementations for Value. + + public boolean isParticular() + { + return type == null; + } + + + public final String internalType() + { + return + type == null ? ClassConstants.TYPE_JAVA_LANG_OBJECT : + ClassUtil.isInternalArrayType(type) ? type : + ClassConstants.TYPE_CLASS_START + + type + + ClassConstants.TYPE_CLASS_END; + } + + + // Implementations for Object. + + public boolean equals(Object object) + { + if (this == object) + { + return true; + } + + if (object == null || + this.getClass() != object.getClass()) + { + return false; + } + + TypedReferenceValue other = (TypedReferenceValue)object; + return this.type == null ? other.type == null : + (this.mayBeNull == other.mayBeNull && + this.type.equals(other.type)); + } + + + public int hashCode() + { + return this.getClass().hashCode() ^ + (type == null ? 0 : type.hashCode() ^ (mayBeNull ? 0 : 1)); + } + + + public String toString() + { + return type == null ? + "null" : + type + (referencedClass == null ? "?" : "") + (mayBeNull ? "" : "!"); + } +} |