| /* | |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification | |
| * of Java bytecode. | |
| * | |
| * Copyright (c) 2002-2017 Eric Lafortune @ GuardSquare | |
| * | |
| * 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.shrink; | |
| import proguard.classfile.*; | |
| import proguard.classfile.attribute.*; | |
| import proguard.classfile.attribute.annotation.*; | |
| import proguard.classfile.attribute.annotation.visitor.*; | |
| import proguard.classfile.attribute.visitor.*; | |
| import proguard.classfile.constant.*; | |
| import proguard.classfile.editor.*; | |
| import proguard.classfile.util.*; | |
| import proguard.classfile.visitor.*; | |
| import java.util.Arrays; | |
| /** | |
| * This ClassVisitor removes constant pool entries, class members, and other | |
| * class elements that are not marked as being used. | |
| * | |
| * @see UsageMarker | |
| * | |
| * @author Eric Lafortune | |
| */ | |
| public class ClassShrinker | |
| extends SimplifiedVisitor | |
| implements ClassVisitor, | |
| MemberVisitor, | |
| AttributeVisitor, | |
| AnnotationVisitor, | |
| ElementValueVisitor | |
| { | |
| private final UsageMarker usageMarker; | |
| private int[] constantIndexMap = new int[ClassConstants.TYPICAL_CONSTANT_POOL_SIZE]; | |
| private int[] bootstrapMethodIndexMap = new int[ClassConstants.TYPICAL_CONSTANT_POOL_SIZE]; | |
| private final ConstantPoolRemapper constantPoolRemapper = new ConstantPoolRemapper(); | |
| private final BootstrapMethodRemapper bootstrapMethodRemapper = new BootstrapMethodRemapper(); | |
| /** | |
| * Creates a new ClassShrinker. | |
| * @param usageMarker the usage marker that is used to mark the classes | |
| * and class members. | |
| */ | |
| public ClassShrinker(UsageMarker usageMarker) | |
| { | |
| this.usageMarker = usageMarker; | |
| } | |
| // Implementations for ClassVisitor. | |
| public void visitProgramClass(ProgramClass programClass) | |
| { | |
| // Shrink the arrays for constant pool, interfaces, fields, methods, | |
| // and class attributes. | |
| if (programClass.u2interfacesCount > 0) | |
| { | |
| new InterfaceDeleter(shrinkFlags(programClass.constantPool, | |
| programClass.u2interfaces, | |
| programClass.u2interfacesCount)) | |
| .visitProgramClass(programClass); | |
| } | |
| // Shrinking the constant pool also sets up an index map. | |
| int newConstantPoolCount = | |
| shrinkConstantPool(programClass.constantPool, | |
| programClass.u2constantPoolCount); | |
| programClass.u2fieldsCount = | |
| shrinkArray(programClass.fields, | |
| programClass.u2fieldsCount); | |
| programClass.u2methodsCount = | |
| shrinkArray(programClass.methods, | |
| programClass.u2methodsCount); | |
| programClass.u2attributesCount = | |
| shrinkArray(programClass.attributes, | |
| programClass.u2attributesCount); | |
| // Compact the remaining fields, methods, and attributes, | |
| // and remap their references to the constant pool. | |
| programClass.fieldsAccept(this); | |
| programClass.methodsAccept(this); | |
| programClass.attributesAccept(this); | |
| // Remap the references to the constant pool if it has shrunk. | |
| if (newConstantPoolCount < programClass.u2constantPoolCount) | |
| { | |
| programClass.u2constantPoolCount = newConstantPoolCount; | |
| // Remap all constant pool references. | |
| constantPoolRemapper.setConstantIndexMap(constantIndexMap); | |
| constantPoolRemapper.visitProgramClass(programClass); | |
| } | |
| // Replace any unused classes in the signatures. | |
| MySignatureCleaner signatureCleaner = new MySignatureCleaner(); | |
| programClass.fieldsAccept(new AllAttributeVisitor(signatureCleaner)); | |
| programClass.methodsAccept(new AllAttributeVisitor(signatureCleaner)); | |
| programClass.attributesAccept(signatureCleaner); | |
| // Compact the extra field pointing to the subclasses of this class. | |
| programClass.subClasses = | |
| shrinkToNewArray(programClass.subClasses); | |
| } | |
| public void visitLibraryClass(LibraryClass libraryClass) | |
| { | |
| // Library classes are left unchanged. | |
| // Compact the extra field pointing to the subclasses of this class. | |
| libraryClass.subClasses = | |
| shrinkToNewArray(libraryClass.subClasses); | |
| } | |
| // Implementations for MemberVisitor. | |
| public void visitProgramMember(ProgramClass programClass, ProgramMember programMember) | |
| { | |
| // Shrink the attributes array. | |
| programMember.u2attributesCount = | |
| shrinkArray(programMember.attributes, | |
| programMember.u2attributesCount); | |
| // Shrink any attributes. | |
| programMember.attributesAccept(programClass, this); | |
| } | |
| // Implementations for AttributeVisitor. | |
| public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} | |
| public void visitBootstrapMethodsAttribute(Clazz clazz, BootstrapMethodsAttribute bootstrapMethodsAttribute) | |
| { | |
| // Shrink the array of BootstrapMethodInfo objects. | |
| int newBootstrapMethodsCount = | |
| shrinkBootstrapMethodArray(bootstrapMethodsAttribute.bootstrapMethods, | |
| bootstrapMethodsAttribute.u2bootstrapMethodsCount); | |
| if (newBootstrapMethodsCount < bootstrapMethodsAttribute.u2bootstrapMethodsCount) | |
| { | |
| bootstrapMethodsAttribute.u2bootstrapMethodsCount = newBootstrapMethodsCount; | |
| // Remap all constant pool references. | |
| bootstrapMethodRemapper.setConstantIndexMap(bootstrapMethodIndexMap); | |
| clazz.constantPoolEntriesAccept(bootstrapMethodRemapper); | |
| } | |
| } | |
| public void visitInnerClassesAttribute(Clazz clazz, InnerClassesAttribute innerClassesAttribute) | |
| { | |
| // Shrink the array of InnerClassesInfo objects. | |
| innerClassesAttribute.u2classesCount = | |
| shrinkArray(innerClassesAttribute.classes, | |
| innerClassesAttribute.u2classesCount); | |
| } | |
| public void visitEnclosingMethodAttribute(Clazz clazz, EnclosingMethodAttribute enclosingMethodAttribute) | |
| { | |
| // Sometimes, a class is still referenced (apparently as a dummy class), | |
| // but its enclosing method is not. Then remove the reference to | |
| // the enclosing method. | |
| // E.g. the anonymous inner class javax.swing.JList$1 is defined inside | |
| // a constructor of javax.swing.JList, but it is also referenced as a | |
| // dummy argument in a constructor of javax.swing.JList$ListSelectionHandler. | |
| if (enclosingMethodAttribute.referencedMethod != null && | |
| !usageMarker.isUsed(enclosingMethodAttribute.referencedMethod)) | |
| { | |
| enclosingMethodAttribute.u2nameAndTypeIndex = 0; | |
| enclosingMethodAttribute.referencedMethod = null; | |
| } | |
| } | |
| public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) | |
| { | |
| // Shrink the attributes array. | |
| codeAttribute.u2attributesCount = | |
| shrinkArray(codeAttribute.attributes, | |
| codeAttribute.u2attributesCount); | |
| // Shrink the attributes themselves. | |
| codeAttribute.attributesAccept(clazz, method, this); | |
| } | |
| public void visitLocalVariableTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTableAttribute localVariableTableAttribute) | |
| { | |
| // Shrink the local variable info array. | |
| localVariableTableAttribute.u2localVariableTableLength = | |
| shrinkArray(localVariableTableAttribute.localVariableTable, | |
| localVariableTableAttribute.u2localVariableTableLength); | |
| } | |
| public void visitLocalVariableTypeTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeTableAttribute localVariableTypeTableAttribute) | |
| { | |
| // Shrink the local variable type info array. | |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength = | |
| shrinkArray(localVariableTypeTableAttribute.localVariableTypeTable, | |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength); | |
| } | |
| public void visitAnyAnnotationsAttribute(Clazz clazz, AnnotationsAttribute annotationsAttribute) | |
| { | |
| // Shrink the annotations array. | |
| annotationsAttribute.u2annotationsCount = | |
| shrinkArray(annotationsAttribute.annotations, | |
| annotationsAttribute.u2annotationsCount); | |
| // Shrink the annotations themselves. | |
| annotationsAttribute.annotationsAccept(clazz, this); | |
| } | |
| public void visitAnyParameterAnnotationsAttribute(Clazz clazz, Method method, ParameterAnnotationsAttribute parameterAnnotationsAttribute) | |
| { | |
| // Loop over all parameters. | |
| for (int parameterIndex = 0; parameterIndex < parameterAnnotationsAttribute.u1parametersCount; parameterIndex++) | |
| { | |
| // Shrink the parameter annotations array. | |
| parameterAnnotationsAttribute.u2parameterAnnotationsCount[parameterIndex] = | |
| shrinkArray(parameterAnnotationsAttribute.parameterAnnotations[parameterIndex], | |
| parameterAnnotationsAttribute.u2parameterAnnotationsCount[parameterIndex]); | |
| } | |
| // Shrink the annotations themselves. | |
| parameterAnnotationsAttribute.annotationsAccept(clazz, method, this); | |
| } | |
| // Implementations for AnnotationVisitor. | |
| public void visitAnnotation(Clazz clazz, Annotation annotation) | |
| { | |
| // Shrink the element values array. | |
| annotation.u2elementValuesCount = | |
| shrinkArray(annotation.elementValues, | |
| annotation.u2elementValuesCount); | |
| // Shrink the element values themselves. | |
| annotation.elementValuesAccept(clazz, this); | |
| } | |
| /** | |
| * This AttributeVisitor updates the Utf8 constants of signatures | |
| * of classes, fields, and methods. | |
| */ | |
| private class MySignatureCleaner | |
| extends SimplifiedVisitor | |
| implements AttributeVisitor | |
| { | |
| public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} | |
| public void visitSignatureAttribute(Clazz clazz, SignatureAttribute signatureAttribute) | |
| { | |
| Clazz[] referencedClasses = signatureAttribute.referencedClasses; | |
| if (referencedClasses != null) | |
| { | |
| // Go over the classes in the signature. | |
| String signature = signatureAttribute.getSignature(clazz); | |
| DescriptorClassEnumeration classEnumeration = | |
| new DescriptorClassEnumeration(signature); | |
| int referencedClassIndex = 0; | |
| // Start construction a new signature. | |
| StringBuffer newSignatureBuffer = new StringBuffer(); | |
| newSignatureBuffer.append(classEnumeration.nextFluff()); | |
| while (classEnumeration.hasMoreClassNames()) | |
| { | |
| String className = classEnumeration.nextClassName(); | |
| // Replace the class name if it is unused. | |
| Clazz referencedClass = referencedClasses[referencedClassIndex]; | |
| if (referencedClass != null && | |
| !usageMarker.isUsed(referencedClass)) | |
| { | |
| className = ClassConstants.NAME_JAVA_LANG_OBJECT; | |
| referencedClasses[referencedClassIndex] = null; | |
| } | |
| // Use a short name if it's an inner class after a '.' | |
| // separator. | |
| else if (classEnumeration.isInnerClassName()) | |
| { | |
| className = className.substring(className.lastIndexOf(ClassConstants.INNER_CLASS_SEPARATOR)+1); | |
| } | |
| referencedClassIndex++; | |
| newSignatureBuffer.append(className); | |
| newSignatureBuffer.append(classEnumeration.nextFluff()); | |
| } | |
| // Update the signature. | |
| ((Utf8Constant)((ProgramClass)clazz).constantPool[signatureAttribute.u2signatureIndex]).setString(newSignatureBuffer.toString()); | |
| } | |
| } | |
| } | |
| // Implementations for ElementValueVisitor. | |
| public void visitAnyElementValue(Clazz clazz, Annotation annotation, ElementValue elementValue) {} | |
| public void visitAnnotationElementValue(Clazz clazz, Annotation annotation, AnnotationElementValue annotationElementValue) | |
| { | |
| // Shrink the contained annotation. | |
| annotationElementValue.annotationAccept(clazz, this); | |
| } | |
| public void visitArrayElementValue(Clazz clazz, Annotation annotation, ArrayElementValue arrayElementValue) | |
| { | |
| // Shrink the element values array. | |
| arrayElementValue.u2elementValuesCount = | |
| shrinkArray(arrayElementValue.elementValues, | |
| arrayElementValue.u2elementValuesCount); | |
| // Shrink the element values themselves. | |
| arrayElementValue.elementValuesAccept(clazz, annotation, this); | |
| } | |
| // Small utility methods. | |
| /** | |
| * Removes all entries that are not marked as being used from the given | |
| * constant pool. Creates a map from the old indices to the new indices | |
| * as a side effect. | |
| * @return the new number of entries. | |
| */ | |
| private int shrinkConstantPool(Constant[] constantPool, int length) | |
| { | |
| if (constantIndexMap.length < length) | |
| { | |
| constantIndexMap = new int[length]; | |
| } | |
| int counter = 1; | |
| boolean isUsed = false; | |
| // Shift the used constant pool entries together. | |
| for (int index = 1; index < length; index++) | |
| { | |
| constantIndexMap[index] = counter; | |
| Constant constant = constantPool[index]; | |
| // Is the constant being used? Don't update the flag if this is the | |
| // second half of a long entry. | |
| if (constant != null) | |
| { | |
| isUsed = usageMarker.isUsed(constant); | |
| } | |
| if (isUsed) | |
| { | |
| // Remember the new index. | |
| constantIndexMap[index] = counter; | |
| // Shift the constant pool entry. | |
| constantPool[counter++] = constant; | |
| } | |
| else | |
| { | |
| // Remember an invalid index. | |
| constantIndexMap[index] = -1; | |
| } | |
| } | |
| // Clear the remaining constant pool elements. | |
| Arrays.fill(constantPool, counter, length, null); | |
| return counter; | |
| } | |
| /** | |
| * Creates an array marking unused constant pool entries for all the | |
| * elements in the given array of constant pool indices. | |
| * @return an array of flags indicating unused elements. | |
| */ | |
| private boolean[] shrinkFlags(Constant[] constantPool, int[] array, int length) | |
| { | |
| boolean[] unused = new boolean[length]; | |
| // Shift the used objects together. | |
| for (int index = 0; index < length; index++) | |
| { | |
| if (!usageMarker.isUsed(constantPool[array[index]])) | |
| { | |
| unused[index] = true; | |
| } | |
| } | |
| return unused; | |
| } | |
| /** | |
| * Removes all indices that point to unused constant pool entries | |
| * from the given array. | |
| * @return the new number of indices. | |
| */ | |
| private int shrinkConstantIndexArray(Constant[] constantPool, int[] array, int length) | |
| { | |
| int counter = 0; | |
| // Shift the used objects together. | |
| for (int index = 0; index < length; index++) | |
| { | |
| if (usageMarker.isUsed(constantPool[array[index]])) | |
| { | |
| array[counter++] = array[index]; | |
| } | |
| } | |
| // Clear the remaining array elements. | |
| Arrays.fill(array, counter, length, 0); | |
| return counter; | |
| } | |
| /** | |
| * Removes all Clazz objects that are not marked as being used | |
| * from the given array and returns the remaining objects in a an array | |
| * of the right size. | |
| * @return the new array. | |
| */ | |
| private Clazz[] shrinkToNewArray(Clazz[] array) | |
| { | |
| if (array == null) | |
| { | |
| return null; | |
| } | |
| // Shrink the given array in-place. | |
| int length = shrinkArray(array, array.length); | |
| if (length == 0) | |
| { | |
| return null; | |
| } | |
| // Return immediately if the array is of right size already. | |
| if (length == array.length) | |
| { | |
| return array; | |
| } | |
| // Copy the remaining elements into a new array of the right size. | |
| Clazz[] newArray = new Clazz[length]; | |
| System.arraycopy(array, 0, newArray, 0, length); | |
| return newArray; | |
| } | |
| /** | |
| * Removes all entries that are not marked as being used from the given | |
| * array of bootstrap methods. Creates a map from the old indices to the | |
| * new indices as a side effect. | |
| * @return the new number of entries. | |
| */ | |
| private int shrinkBootstrapMethodArray(BootstrapMethodInfo[] bootstrapMethods, int length) | |
| { | |
| if (bootstrapMethodIndexMap.length < length) | |
| { | |
| bootstrapMethodIndexMap = new int[length]; | |
| } | |
| int counter = 0; | |
| // Shift the used bootstrap methods together. | |
| for (int index = 0; index < length; index++) | |
| { | |
| BootstrapMethodInfo bootstrapMethod = bootstrapMethods[index]; | |
| // Is the entry being used? | |
| if (usageMarker.isUsed(bootstrapMethod)) | |
| { | |
| // Remember the new index. | |
| bootstrapMethodIndexMap[index] = counter; | |
| // Shift the entry. | |
| bootstrapMethods[counter++] = bootstrapMethod; | |
| } | |
| else | |
| { | |
| // Remember an invalid index. | |
| bootstrapMethodIndexMap[index] = -1; | |
| } | |
| } | |
| // Clear the remaining bootstrap methods. | |
| Arrays.fill(bootstrapMethods, counter, length, null); | |
| return counter; | |
| } | |
| /** | |
| * Removes all VisitorAccepter objects that are not marked as being used | |
| * from the given array. | |
| * @return the new number of VisitorAccepter objects. | |
| */ | |
| private int shrinkArray(VisitorAccepter[] array, int length) | |
| { | |
| int counter = 0; | |
| // Shift the used objects together. | |
| for (int index = 0; index < length; index++) | |
| { | |
| VisitorAccepter visitorAccepter = array[index]; | |
| if (usageMarker.isUsed(visitorAccepter)) | |
| { | |
| array[counter++] = visitorAccepter; | |
| } | |
| } | |
| // Clear any remaining array elements. | |
| if (counter < length) | |
| { | |
| Arrays.fill(array, counter, length, null); | |
| } | |
| return counter; | |
| } | |
| } |