This is a prerequisite for the static scrambling transformer. As it moves methods/fields around, it requires their visibilities to be updated.pull/66/head
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package dev.openrs2.deob.transform |
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import com.github.michaelbull.logging.InlineLogger |
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import com.google.common.collect.HashMultimap |
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import com.google.common.collect.Multimap |
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import dev.openrs2.asm.ClassForNameUtils |
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import dev.openrs2.asm.MemberDesc |
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import dev.openrs2.asm.MemberRef |
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import dev.openrs2.asm.classpath.ClassPath |
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import dev.openrs2.asm.classpath.Library |
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import dev.openrs2.asm.transform.Transformer |
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import dev.openrs2.common.collect.DisjointSet |
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import org.objectweb.asm.Opcodes |
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import org.objectweb.asm.Type |
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import org.objectweb.asm.tree.ClassNode |
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import org.objectweb.asm.tree.FieldInsnNode |
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import org.objectweb.asm.tree.MethodInsnNode |
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import org.objectweb.asm.tree.MethodNode |
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class VisibilityTransformer : Transformer() { |
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private lateinit var inheritedFieldSets: DisjointSet<MemberRef> |
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private lateinit var inheritedMethodSets: DisjointSet<MemberRef> |
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private val fieldReferences = HashMultimap.create<DisjointSet.Partition<MemberRef>, String>() |
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private val methodReferences = HashMultimap.create<DisjointSet.Partition<MemberRef>, String>() |
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private val publicCtorClasses = mutableSetOf<String>() |
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override fun preTransform(classPath: ClassPath) { |
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inheritedFieldSets = classPath.createInheritedFieldSets() |
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inheritedMethodSets = classPath.createInheritedMethodSets() |
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fieldReferences.clear() |
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methodReferences.clear() |
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publicCtorClasses.clear() |
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publicCtorClasses.addAll(DEFAULT_PUBLIC_CTOR_CLASSES) |
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} |
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override fun transformCode(classPath: ClassPath, library: Library, clazz: ClassNode, method: MethodNode): Boolean { |
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for (name in ClassForNameUtils.findClassNames(method)) { |
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val loadedClass = classPath[name] |
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if (loadedClass != null && !loadedClass.dependency) { |
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publicCtorClasses.add(name) |
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} |
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} |
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for (insn in method.instructions) { |
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when (insn) { |
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is FieldInsnNode -> addReference(fieldReferences, inheritedFieldSets, MemberRef(insn), clazz.name) |
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is MethodInsnNode -> addReference(methodReferences, inheritedMethodSets, MemberRef(insn), clazz.name) |
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} |
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} |
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return false |
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} |
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private fun getVisibility( |
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classPath: ClassPath, |
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references: Multimap<DisjointSet.Partition<MemberRef>, String>, |
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disjointSet: DisjointSet<MemberRef>, |
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member: MemberRef, |
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access: Int |
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): Int { |
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val method = Type.getType(member.desc).sort == Type.METHOD |
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if (method) { |
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if (member.name == "<clinit>") { |
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// the visibility flags don't really matter - we use package-private to match javac |
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return 0 |
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} else if (member.owner in publicCtorClasses && member.name == "<init>") { |
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// constructors invoked with reflection (including applets) must be public |
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return Opcodes.ACC_PUBLIC |
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} else if (member.name in PUBLIC_METHODS) { |
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// methods invoked with reflection must also be public |
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return Opcodes.ACC_PUBLIC |
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} |
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} |
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val partition = disjointSet[member]!! |
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val overridable = method && member.name != "<init>" |
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val hasOverride = overridable && partition.count { classPath[it.owner]!!.methods.contains(MemberDesc(it)) } > 1 |
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val abstract = method && access and Opcodes.ACC_ABSTRACT != 0 |
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val partitionReferences = references[partition] |
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val partitionOwners = partition.map(MemberRef::owner).toSet() |
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// pick the weakest access level based on references in our own code |
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val visibility = when { |
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partitionReferences.all { it == member.owner } && !hasOverride && !abstract -> Opcodes.ACC_PRIVATE |
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partitionReferences.all { partitionOwners.contains(it) } -> Opcodes.ACC_PROTECTED |
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else -> Opcodes.ACC_PUBLIC |
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} |
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return if (overridable) { |
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// reduce it to the weakest level required to override a dependency's method |
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partition.filter { classPath[it.owner]!!.dependency } |
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.mapNotNull { classPath[it.owner]!!.getAccess(MemberDesc(it)) } |
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.fold(visibility, ::weakestVisibility) |
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} else { |
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visibility |
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} |
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} |
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override fun postTransform(classPath: ClassPath) { |
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logger.info { "Identified constructors invoked with reflection $publicCtorClasses" } |
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var classesChanged = 0 |
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var fieldsChanged = 0 |
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var methodsChanged = 0 |
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for (library in classPath.libraries) { |
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for (clazz in library) { |
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val classAccess = clazz.access |
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clazz.access = (classAccess and VISIBILITY_FLAGS.inv()) or Opcodes.ACC_PUBLIC |
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if (clazz.access != classAccess) { |
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classesChanged++ |
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} |
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for (field in clazz.fields) { |
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val access = field.access |
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val visibility = getVisibility( |
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classPath, |
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fieldReferences, |
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inheritedFieldSets, |
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MemberRef(clazz, field), |
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access |
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) |
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field.access = (access and VISIBILITY_FLAGS.inv()) or visibility |
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if (field.access != access) { |
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fieldsChanged++ |
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} |
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} |
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for (method in clazz.methods) { |
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val access = method.access |
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val visibility = getVisibility( |
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classPath, |
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methodReferences, |
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inheritedMethodSets, |
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MemberRef(clazz, method), |
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access |
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) |
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method.access = (access and VISIBILITY_FLAGS.inv()) or visibility |
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if (method.access != access) { |
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methodsChanged++ |
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} |
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} |
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} |
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} |
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logger.info { |
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"Updated visibility of $classesChanged classes, $fieldsChanged fields and $methodsChanged methods" |
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} |
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} |
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companion object { |
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private val logger = InlineLogger() |
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private const val VISIBILITY_FLAGS = Opcodes.ACC_PUBLIC or Opcodes.ACC_PROTECTED or Opcodes.ACC_PRIVATE |
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private val DEFAULT_PUBLIC_CTOR_CLASSES = setOf("client", "loader") |
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private val PUBLIC_METHODS = setOf("main", "providesignlink") |
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private fun addReference( |
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references: Multimap<DisjointSet.Partition<MemberRef>, String>, |
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disjointSet: DisjointSet<MemberRef>, |
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member: MemberRef, |
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className: String |
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) { |
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val partition = disjointSet[member] ?: return |
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references.put(partition, className) |
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} |
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private fun weakestVisibility(a: Int, b: Int): Int { |
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return when { |
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a and Opcodes.ACC_PUBLIC != 0 || b and Opcodes.ACC_PUBLIC != 0 -> Opcodes.ACC_PUBLIC |
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// map package-private to public |
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a and VISIBILITY_FLAGS == 0 || b and VISIBILITY_FLAGS == 0 -> Opcodes.ACC_PUBLIC |
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a and Opcodes.ACC_PROTECTED != 0 || b and Opcodes.ACC_PROTECTED != 0 -> Opcodes.ACC_PROTECTED |
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else -> Opcodes.ACC_PRIVATE |
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} |
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} |
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} |
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} |
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