bb-tools/proguard4.7/src/proguard/optimize/peephole/ClassMerger.java
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2011 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.optimize.peephole;
import proguard.classfile.*;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.visitor.*;
import proguard.classfile.editor.*;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;
import proguard.optimize.KeepMarker;
import proguard.optimize.info.*;
import proguard.util.*;
import java.util.*;
/**
* This ClassVisitor inlines the classes that it visits in a given target class,
* whenever possible.
*
* @see RetargetedInnerClassAttributeRemover
* @see TargetClassChanger
* @see ClassReferenceFixer
* @see MemberReferenceFixer
* @see AccessFixer
* @author Eric Lafortune
*/
public class ClassMerger
extends SimplifiedVisitor
implements ClassVisitor,
ConstantVisitor
{
//*
private static final boolean DEBUG = false;
/*/
private static boolean DEBUG = true;
//*/
private final ProgramClass targetClass;
private final boolean allowAccessModification;
private final boolean mergeInterfacesAggressively;
private final ClassVisitor extraClassVisitor;
private final MemberVisitor fieldOptimizationInfoCopier = new FieldOptimizationInfoCopier();
/**
* Creates a new ClassMerger that will merge classes into the given target
* class.
* @param targetClass the class into which all visited
* classes will be merged.
* @param allowAccessModification specifies whether the access modifiers
* of classes can be changed in order to
* merge them.
* @param mergeInterfacesAggressively specifies whether interfaces may
* be merged aggressively.
*/
public ClassMerger(ProgramClass targetClass,
boolean allowAccessModification,
boolean mergeInterfacesAggressively)
{
this(targetClass, allowAccessModification, mergeInterfacesAggressively, null);
}
/**
* Creates a new ClassMerger that will merge classes into the given target
* class.
* @param targetClass the class into which all visited
* classes will be merged.
* @param allowAccessModification specifies whether the access modifiers
* of classes can be changed in order to
* merge them.
* @param mergeInterfacesAggressively specifies whether interfaces may
* be merged aggressively.
* @param extraClassVisitor an optional extra visitor for all
* merged classes.
*/
public ClassMerger(ProgramClass targetClass,
boolean allowAccessModification,
boolean mergeInterfacesAggressively,
ClassVisitor extraClassVisitor)
{
this.targetClass = targetClass;
this.allowAccessModification = allowAccessModification;
this.mergeInterfacesAggressively = mergeInterfacesAggressively;
this.extraClassVisitor = extraClassVisitor;
}
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
//final String CLASS_NAME = "abc/Def";
//DEBUG = programClass.getName().equals(CLASS_NAME) ||
// targetClass.getName().equals(CLASS_NAME);
// TODO: Remove this when the class merger has stabilized.
// Catch any unexpected exceptions from the actual visiting method.
try
{
visitProgramClass0(programClass);
}
catch (RuntimeException ex)
{
System.err.println("Unexpected error while merging classes:");
System.err.println(" Class = ["+programClass.getName()+"]");
System.err.println(" Target class = ["+targetClass.getName()+"]");
System.err.println(" Exception = ["+ex.getClass().getName()+"] ("+ex.getMessage()+")");
if (DEBUG)
{
programClass.accept(new ClassPrinter());
targetClass.accept(new ClassPrinter());
}
throw ex;
}
}
public void visitProgramClass0(ProgramClass programClass)
{
if (!programClass.equals(targetClass) &&
// Don't merge classes that must be preserved.
!KeepMarker.isKept(programClass) &&
!KeepMarker.isKept(targetClass) &&
// Only merge classes that haven't been retargeted yet.
getTargetClass(programClass) == null &&
getTargetClass(targetClass) == null &&
// Don't merge annotation classes, with all their introspection and
// infinite recursion.
(programClass.getAccessFlags() & ClassConstants.INTERNAL_ACC_ANNOTATTION) == 0 &&
// Only merge classes if we can change the access permissions, or
// if they are in the same package, or
// if they are public and don't contain or invoke package visible
// class members.
(allowAccessModification ||
((programClass.getAccessFlags() &
targetClass.getAccessFlags() &
ClassConstants.INTERNAL_ACC_PUBLIC) != 0 &&
!PackageVisibleMemberContainingClassMarker.containsPackageVisibleMembers(programClass) &&
!PackageVisibleMemberInvokingClassMarker.invokesPackageVisibleMembers(programClass)) ||
ClassUtil.internalPackageName(programClass.getName()).equals(
ClassUtil.internalPackageName(targetClass.getName()))) &&
// Only merge two classes or two interfaces or two abstract classes,
// or a class into an interface with a single implementation.
((programClass.getAccessFlags() &
(ClassConstants.INTERNAL_ACC_INTERFACE |
ClassConstants.INTERNAL_ACC_ABSTRACT)) ==
(targetClass.getAccessFlags() &
(ClassConstants.INTERNAL_ACC_INTERFACE |
ClassConstants.INTERNAL_ACC_ABSTRACT)) ||
(isOnlySubClass(programClass, targetClass) &&
(programClass.getSuperClass().equals(targetClass) ||
programClass.getSuperClass().equals(targetClass.getSuperClass())))) &&
// One class must not implement the other class indirectly.
!indirectlyImplementedInterfaces(programClass).contains(targetClass) &&
!targetClass.extendsOrImplements(programClass) &&
// The two classes must have the same superclasses and interfaces
// with static initializers.
initializedSuperClasses(programClass).equals(initializedSuperClasses(targetClass)) &&
// The two classes must have the same superclasses and interfaces
// that are tested with 'instanceof'.
instanceofedSuperClasses(programClass).equals(instanceofedSuperClasses(targetClass)) &&
// The two classes must have the same superclasses that are caught
// as exceptions.
caughtSuperClasses(programClass).equals(caughtSuperClasses(targetClass)) &&
// The two classes must not both be part of a .class construct.
!(DotClassMarker.isDotClassed(programClass) &&
DotClassMarker.isDotClassed(targetClass)) &&
// The two classes must not introduce any unwanted fields.
!introducesUnwantedFields(programClass, targetClass) &&
!introducesUnwantedFields(targetClass, programClass) &&
// The classes must not have clashing constructors.
!haveAnyIdenticalInitializers(programClass, targetClass) &&
// The classes must not introduce abstract methods, unless
// explicitly allowed.
(mergeInterfacesAggressively ||
(!introducesUnwantedAbstractMethods(programClass, targetClass) &&
!introducesUnwantedAbstractMethods(targetClass, programClass))) &&
// The classes must not override each others concrete methods.
!overridesAnyMethods(programClass, targetClass) &&
!overridesAnyMethods(targetClass, programClass) &&
// The classes must not shadow each others non-private methods.
!shadowsAnyMethods(programClass, targetClass) &&
!shadowsAnyMethods(targetClass, programClass))
{
if (DEBUG)
{
System.out.println("ClassMerger ["+programClass.getName()+"] -> ["+targetClass.getName()+"]");
System.out.println(" Source interface? ["+((programClass.getAccessFlags() & ClassConstants.INTERNAL_ACC_INTERFACE)!=0)+"]");
System.out.println(" Target interface? ["+((targetClass.getAccessFlags() & ClassConstants.INTERNAL_ACC_INTERFACE)!=0)+"]");
System.out.println(" Source subclasses ["+programClass.subClasses+"]");
System.out.println(" Target subclasses ["+targetClass.subClasses+"]");
System.out.println(" Source superclass ["+programClass.getSuperClass().getName()+"]");
System.out.println(" Target superclass ["+targetClass.getSuperClass().getName()+"]");
}
// Combine the access flags.
int targetAccessFlags = targetClass.getAccessFlags();
int sourceAccessFlags = programClass.getAccessFlags();
targetClass.u2accessFlags =
((targetAccessFlags &
sourceAccessFlags) &
(ClassConstants.INTERNAL_ACC_INTERFACE |
ClassConstants.INTERNAL_ACC_ABSTRACT)) |
((targetAccessFlags |
sourceAccessFlags) &
(ClassConstants.INTERNAL_ACC_PUBLIC |
ClassConstants.INTERNAL_ACC_SUPER |
ClassConstants.INTERNAL_ACC_ANNOTATTION |
ClassConstants.INTERNAL_ACC_ENUM));
// Copy over the superclass, unless it's the target class itself.
//if (!targetClass.getName().equals(programClass.getSuperName()))
//{
// targetClass.u2superClass =
// new ConstantAdder(targetClass).addConstant(programClass, programClass.u2superClass);
//}
// Copy over the interfaces that aren't present yet and that
// wouldn't cause loops in the class hierarchy.
programClass.interfaceConstantsAccept(
new ExceptClassConstantFilter(targetClass.getName(),
new ImplementedClassConstantFilter(targetClass,
new ImplementingClassConstantFilter(targetClass,
new InterfaceAdder(targetClass)))));
// Copy over the class members.
MemberAdder memberAdder =
new MemberAdder(targetClass, fieldOptimizationInfoCopier);
programClass.fieldsAccept(memberAdder);
programClass.methodsAccept(memberAdder);
// Copy over the other attributes.
programClass.attributesAccept(
new AttributeAdder(targetClass, true));
// Update the optimization information of the target class.
ClassOptimizationInfo info =
ClassOptimizationInfo.getClassOptimizationInfo(targetClass);
if (info != null)
{
info.merge(ClassOptimizationInfo.getClassOptimizationInfo(programClass));
}
// Remember to replace the inlined class by the target class.
setTargetClass(programClass, targetClass);
// Visit the merged class, if required.
if (extraClassVisitor != null)
{
extraClassVisitor.visitProgramClass(programClass);
}
}
}
// Small utility methods.
/**
* Returns whether a given class is the only subclass of another given class.
*/
private boolean isOnlySubClass(Clazz subClass,
ProgramClass clazz)
{
// TODO: The list of subclasses is not up to date.
return clazz.subClasses != null &&
clazz.subClasses.length == 1 &&
clazz.subClasses[0].equals(subClass);
}
/**
* Returns the set of indirectly implemented interfaces.
*/
private Set indirectlyImplementedInterfaces(Clazz clazz)
{
Set set = new HashSet();
ReferencedClassVisitor referencedInterfaceCollector =
new ReferencedClassVisitor(
new ClassHierarchyTraveler(false, false, true, false,
new ClassCollector(set)));
// Visit all superclasses and collect their interfaces.
clazz.superClassConstantAccept(referencedInterfaceCollector);
// Visit all interfaces and collect their interfaces.
clazz.interfaceConstantsAccept(referencedInterfaceCollector);
return set;
}
/**
* Returns the set of superclasses and interfaces that are initialized.
*/
private Set initializedSuperClasses(Clazz clazz)
{
Set set = new HashSet();
// Visit all superclasses and interfaces, collecting the ones that have
// static initializers.
clazz.hierarchyAccept(true, true, true, false,
new StaticInitializerContainingClassFilter(
new ClassCollector(set)));
return set;
}
/**
* Returns the set of superclasses and interfaces that are used in
* 'instanceof' tests.
*/
private Set instanceofedSuperClasses(Clazz clazz)
{
Set set = new HashSet();
// Visit all superclasses and interfaces, collecting the ones that are
// used in an 'instanceof' test.
clazz.hierarchyAccept(true, true, true, false,
new InstanceofClassFilter(
new ClassCollector(set)));
return set;
}
/**
* Returns the set of superclasses that are caught as exceptions.
*/
private Set caughtSuperClasses(Clazz clazz)
{
// Don't bother if this isn't an exception at all.
if (!clazz.extends_(ClassConstants.INTERNAL_NAME_JAVA_LANG_THROWABLE))
{
return Collections.EMPTY_SET;
}
// Visit all superclasses, collecting the ones that are caught
// (plus java.lang.Object, in the current implementation).
Set set = new HashSet();
clazz.hierarchyAccept(true, true, false, false,
new CaughtClassFilter(
new ClassCollector(set)));
return set;
}
/**
* Returns whether the given class would introduce any unwanted fields
* in the target class.
*/
private boolean introducesUnwantedFields(ProgramClass programClass,
ProgramClass targetClass)
{
// The class must not have any fields, or it must not be instantiated,
// without any other subclasses.
return
programClass.u2fieldsCount != 0 &&
(InstantiationClassMarker.isInstantiated(targetClass) ||
(targetClass.subClasses != null &&
!isOnlySubClass(programClass, targetClass)));
}
/**
* Returns whether the two given classes have initializers with the same
* descriptors.
*/
private boolean haveAnyIdenticalInitializers(Clazz clazz, Clazz targetClass)
{
MemberCounter counter = new MemberCounter();
// TODO: Currently checking shared methods, not just initializers.
// TODO: Allow identical methods.
// Visit all methods, counting the ones that are also present in the
// target class.
clazz.methodsAccept(//new MemberNameFilter(new FixedStringMatcher(ClassConstants.INTERNAL_METHOD_NAME_INIT),
new SimilarMemberVisitor(targetClass, true, false, false, false,
new MemberAccessFilter(0, ClassConstants.INTERNAL_ACC_ABSTRACT,
counter)));
return counter.getCount() > 0;
}
/**
* Returns whether the given class would introduce any abstract methods
* in the target class.
*/
private boolean introducesUnwantedAbstractMethods(Clazz clazz,
ProgramClass targetClass)
{
// It's ok if the target class is already abstract and it has at most
// the class as a subclass.
if ((targetClass.getAccessFlags() &
(ClassConstants.INTERNAL_ACC_ABSTRACT |
ClassConstants.INTERNAL_ACC_INTERFACE)) != 0 &&
(targetClass.subClasses == null ||
isOnlySubClass(clazz, targetClass)))
{
return false;
}
MemberCounter counter = new MemberCounter();
Set targetSet = new HashSet();
// Collect all abstract methods, and similar abstract methods in the
// class hierarchy of the target class.
clazz.methodsAccept(new MemberAccessFilter(ClassConstants.INTERNAL_ACC_ABSTRACT, 0,
new MultiMemberVisitor(new MemberVisitor[]
{
counter,
new SimilarMemberVisitor(targetClass, true, true, true, false,
new MemberAccessFilter(ClassConstants.INTERNAL_ACC_ABSTRACT, 0,
new MemberCollector(targetSet)))
})));
return targetSet.size() < counter.getCount();
}
/**
* Returns whether the given class overrides any methods in the given
* target class.
*/
private boolean overridesAnyMethods(Clazz clazz, Clazz targetClass)
{
MemberCounter counter = new MemberCounter();
// Visit all non-private non-static methods, counting the ones that are
// being overridden in the class hierarchy of the target class.
clazz.methodsAccept(new MemberAccessFilter(0, ClassConstants.INTERNAL_ACC_PRIVATE | ClassConstants.INTERNAL_ACC_STATIC | ClassConstants.INTERNAL_ACC_ABSTRACT,
new MemberNameFilter(new NotMatcher(new FixedStringMatcher(ClassConstants.INTERNAL_METHOD_NAME_CLINIT)),
new MemberNameFilter(new NotMatcher(new FixedStringMatcher(ClassConstants.INTERNAL_METHOD_NAME_INIT)),
new SimilarMemberVisitor(targetClass, true, true, false, false,
new MemberAccessFilter(0, ClassConstants.INTERNAL_ACC_PRIVATE | ClassConstants.INTERNAL_ACC_STATIC | ClassConstants.INTERNAL_ACC_ABSTRACT,
counter))))));
return counter.getCount() > 0;
}
/**
* Returns whether the given class or its subclasses shadow any methods in
* the given target class.
*/
private boolean shadowsAnyMethods(Clazz clazz, Clazz targetClass)
{
MemberCounter counter = new MemberCounter();
// Visit all private methods, counting the ones that are shadowing
// non-private methods in the class hierarchy of the target class.
clazz.hierarchyAccept(true, false, false, true,
new AllMethodVisitor(
new MemberAccessFilter(ClassConstants.INTERNAL_ACC_PRIVATE, 0,
new MemberNameFilter(new NotMatcher(new FixedStringMatcher(ClassConstants.INTERNAL_METHOD_NAME_INIT)),
new SimilarMemberVisitor(targetClass, true, true, true, false,
new MemberAccessFilter(0, ClassConstants.INTERNAL_ACC_PRIVATE,
counter))))));
// Visit all static methods, counting the ones that are shadowing
// non-private methods in the class hierarchy of the target class.
clazz.hierarchyAccept(true, false, false, true,
new AllMethodVisitor(
new MemberAccessFilter(ClassConstants.INTERNAL_ACC_STATIC, 0,
new MemberNameFilter(new NotMatcher(new FixedStringMatcher(ClassConstants.INTERNAL_METHOD_NAME_CLINIT)),
new SimilarMemberVisitor(targetClass, true, true, true, false,
new MemberAccessFilter(0, ClassConstants.INTERNAL_ACC_PRIVATE,
counter))))));
return counter.getCount() > 0;
}
public static void setTargetClass(Clazz clazz, Clazz targetClass)
{
ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
if (info != null)
{
info.setTargetClass(targetClass);
}
}
public static Clazz getTargetClass(Clazz clazz)
{
Clazz targetClass = null;
// Return the last target class, if any.
while (true)
{
ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
if (info == null)
{
return targetClass;
}
clazz = info.getTargetClass();
if (clazz == null)
{
return targetClass;
}
targetClass = clazz;
}
}
/**
* This MemberVisitor copies field optimization info from copied fields.
*/
private static class FieldOptimizationInfoCopier
extends SimplifiedVisitor
implements MemberVisitor
{
public void visitProgramField(ProgramClass programClass, ProgramField programField)
{
// Copy the optimization info from the field that was just copied.
ProgramField copiedField = (ProgramField)programField.getVisitorInfo();
Object info = copiedField.getVisitorInfo();
programField.setVisitorInfo(info instanceof FieldOptimizationInfo ?
new FieldOptimizationInfo((FieldOptimizationInfo)info) :
info);
}
public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
{
// Linked methods share their optimization info.
}
}
}