proguard.backport.Backporter Maven / Gradle / Ivy
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2018 GuardSquare NV
*
* 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.backport;
import proguard.*;
import proguard.classfile.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.Constant;
import proguard.classfile.editor.*;
import proguard.classfile.instruction.Instruction;
import proguard.classfile.instruction.visitor.InstructionCounter;
import proguard.classfile.util.ClassReferenceInitializer;
import proguard.classfile.visitor.*;
import proguard.optimize.peephole.*;
import proguard.util.MultiValueMap;
/**
* This class backports classes to the specified targetClassVersion.
*
* @author Thomas Neidhart
*/
public class Backporter
{
private final Configuration configuration;
public Backporter(Configuration configuration)
{
this.configuration = configuration;
}
public void execute(ClassPool programClassPool,
ClassPool libraryClassPool,
MultiValueMap injectedClassNameMap)
{
int targetClassVersion = configuration.targetClassVersion;
if (configuration.verbose)
{
System.out.println("Backporting class files...");
}
// Clean up any previous visitor info.
programClassPool.classesAccept(new ClassCleaner());
libraryClassPool.classesAccept(new ClassCleaner());
final InstructionCounter replacedStringConcatCounter = new InstructionCounter();
final ClassCounter lambdaExpressionCounter = new ClassCounter();
final MemberCounter staticInterfaceMethodCounter = new MemberCounter();
final MemberCounter defaultInterfaceMethodCounter = new MemberCounter();
final InstructionCounter replacedMethodCallCounter = new InstructionCounter();
if (targetClassVersion < ClassConstants.CLASS_VERSION_1_9)
{
// Convert indy string concatenations to StringBuilder chains
CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor(true, true);
programClassPool.classesAccept(
new ClassVersionFilter(ClassConstants.CLASS_VERSION_1_9,
new AllAttributeVisitor(
new AttributeNameFilter(ClassConstants.ATTR_BootstrapMethods,
new AttributeToClassVisitor(
new MultiClassVisitor(
new AllMethodVisitor(
new AllAttributeVisitor(
new PeepholeOptimizer(codeAttributeEditor,
// Replace the indy instructions related to String concatenation.
new StringConcatenationConverter(replacedStringConcatCounter,
codeAttributeEditor)))
),
// Clean up unused bootstrap methods and their dangling constants.
new BootstrapMethodsAttributeShrinker(),
// Initialize new references to StringBuilder.
new ClassReferenceInitializer(programClassPool, libraryClassPool)
))))));
}
if (targetClassVersion < ClassConstants.CLASS_VERSION_1_8)
{
// Collect all classes with BootstrapMethod attributes,
// and convert lambda expressions and method references.
ClassPool filteredClasses = new ClassPool();
programClassPool.classesAccept(
new ClassVersionFilter(ClassConstants.CLASS_VERSION_1_8,
new AllAttributeVisitor(
new AttributeNameFilter(ClassConstants.ATTR_BootstrapMethods,
new AttributeToClassVisitor(
new ClassPoolFiller(filteredClasses))))));
// Note: we visit the filtered classes in a separate step
// because we modify the programClassPool while converting
filteredClasses.classesAccept(
new MultiClassVisitor(
// Replace the indy instructions related to lambda expressions.
new LambdaExpressionConverter(programClassPool,
libraryClassPool,
injectedClassNameMap,
lambdaExpressionCounter),
// Clean up unused bootstrap methods and their dangling constants.
new BootstrapMethodsAttributeShrinker(),
// Re-initialize references.
new ClassReferenceInitializer(programClassPool, libraryClassPool)
));
// Remove static and default methods from interfaces if the
// target version is < 1.8. The dalvik format 037 has native
// support for default methods. The dalvik format specification
// does not explicitly mention static interface methods, although
// they seem to work correctly.
ClassPool interfaceClasses = new ClassPool();
programClassPool.classesAccept(
new ClassVersionFilter(ClassConstants.CLASS_VERSION_1_8,
new ClassAccessFilter(ClassConstants.ACC_INTERFACE, 0,
new ClassPoolFiller(interfaceClasses))));
ClassPool modifiedClasses = new ClassPool();
ClassVisitor modifiedClassCollector =
new ClassPoolFiller(modifiedClasses);
interfaceClasses.classesAccept(
new MultiClassVisitor(
new StaticInterfaceMethodConverter(programClassPool,
libraryClassPool,
injectedClassNameMap,
modifiedClassCollector,
staticInterfaceMethodCounter),
new DefaultInterfaceMethodConverter(modifiedClassCollector,
defaultInterfaceMethodCounter)
));
// Re-Initialize references in modified classes.
modifiedClasses.classesAccept(
new ClassReferenceInitializer(programClassPool,
libraryClassPool));
}
if (targetClassVersion < ClassConstants.CLASS_VERSION_1_7)
{
// Replace / remove method calls only available in Java 7+.
InstructionSequenceBuilder ____ =
new InstructionSequenceBuilder(programClassPool,
libraryClassPool);
Instruction[][][] instructions = new Instruction[][][]
{
// Replace Objects.requireNonNull(...) with Object.getClass().
// Starting in JDK 9, javac uses {@code requireNonNull} for
// synthetic null-checks
// (see
// JDK-8074306).
{
____.invokestatic("java/util/Objects",
"requireNonNull",
"(Ljava/lang/Object;)Ljava/lang/Object;").__(),
____.dup()
.invokevirtual(ClassConstants.NAME_JAVA_LANG_OBJECT,
ClassConstants.METHOD_NAME_OBJECT_GET_CLASS,
ClassConstants.METHOD_TYPE_OBJECT_GET_CLASS)
.pop().__()
},
// Remove Throwable.addSuppressed(...).
{
____.invokevirtual("java/util/Throwable",
"addSuppressed",
"(Ljava/lang/Throwable;)V").__(),
____.pop() // the suppressed exception
.pop().__() // the original exception
}
};
Constant[] constants = ____.constants();
CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor();
programClassPool.classesAccept(
new AllMethodVisitor(
new AllAttributeVisitor(
new PeepholeOptimizer(null, codeAttributeEditor,
new InstructionSequencesReplacer(constants,
instructions,
null,
codeAttributeEditor,
replacedMethodCallCounter)))));
}
if (targetClassVersion != 0)
{
// Set the class version of all classes in the program ClassPool
// to the specified target version. This is needed to perform
// optimization on the backported + generated classes.
programClassPool.classesAccept(new ClassVersionSetter(targetClassVersion));
}
if (configuration.verbose)
{
System.out.println(" Number of converted string concatenations: " + replacedStringConcatCounter.getCount());
System.out.println(" Number of converted lambda expressions: " + lambdaExpressionCounter.getCount());
System.out.println(" Number of converted static interface methods: " + staticInterfaceMethodCounter.getCount());
System.out.println(" Number of converted default interface methods: " + defaultInterfaceMethodCounter.getCount());
System.out.println(" Number of replaced Java 7+ method calls: " + replacedMethodCallCounter.getCount());
}
}
}
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