feat: use kotlin intrinsic methods for variables rename (#1207)

README.md

@@ -96,6 +96,7 @@ options:
   --deobf-rewrite-cfg                 - force to ignore and overwrite deobfuscation map file
   --deobf-use-sourcename              - use source file name as class name alias
   --deobf-parse-kotlin-metadata       - parse kotlin metadata to class and package names
+  --use-kotlin-methods-for-var-names  - use kotlin intrinsic methods to rename variables, values: disable, apply, apply-and-hide, default: apply
   --rename-flags                      - fix options (comma-separated list of):
                                          'case' - fix case sensitivity issues (according to --fs-case-sensitive option),
                                          'valid' - rename java identifiers to make them valid,
@@ -107,7 +108,7 @@ options:
   --raw-cfg                           - save methods control flow graph (use raw instructions)
   -f, --fallback                      - make simple dump (using goto instead of 'if', 'for', etc)
   --use-dx                            - use dx/d8 to convert java bytecode
-  --comments-level                    - set code comments level, values: none, user_only, error, warn, info, debug, default: info
+  --comments-level                    - set code comments level, values: error, warn, info, debug, user-only, none, default: info
   --log-level                         - set log level, values: quiet, progress, error, warn, info, debug, default: progress
   -v, --verbose                       - verbose output (set --log-level to DEBUG)
   -q, --quiet                         - turn off output (set --log-level to QUIET)

jadx-cli/src/main/java/jadx/cli/JadxCLIArgs.java

@@ -14,6 +14,7 @@ import com.beust.jcommander.Parameter;
 import jadx.api.CommentsLevel;
 import jadx.api.JadxArgs;
 import jadx.api.JadxArgs.RenameEnum;
+import jadx.api.JadxArgs.UseKotlinMethodsForVarNames;
 import jadx.api.JadxDecompiler;
 import jadx.core.utils.exceptions.JadxException;
 import jadx.core.utils.files.FileUtils;
@@ -101,6 +102,13 @@ public class JadxCLIArgs {
 	@Parameter(names = { "--deobf-parse-kotlin-metadata" }, description = "parse kotlin metadata to class and package names")
 	protected boolean deobfuscationParseKotlinMetadata = false;
 
+	@Parameter(
+			names = { "--use-kotlin-methods-for-var-names" },
+			description = "use kotlin intrinsic methods to rename variables, values: disable, apply, apply-and-hide",
+			converter = UseKotlinMethodsForVarNamesConverter.class
+	)
+	protected UseKotlinMethodsForVarNames useKotlinMethodsForVarNames = UseKotlinMethodsForVarNames.APPLY;
+
 	@Parameter(
 			names = { "--rename-flags" },
 			description = "fix options (comma-separated list of):"
@@ -130,7 +138,7 @@ public class JadxCLIArgs {
 
 	@Parameter(
 			names = { "--comments-level" },
-			description = "set code comments level, values: error, warn, info, debug, user_only, none",
+			description = "set code comments level, values: error, warn, info, debug, user-only, none",
 			converter = CommentsLevelConverter.class
 	)
 	protected CommentsLevel commentsLevel = CommentsLevel.INFO;
@@ -223,6 +231,7 @@ public class JadxCLIArgs {
 		args.setDeobfuscationMaxLength(deobfuscationMaxLength);
 		args.setUseSourceNameAsClassAlias(deobfuscationUseSourceNameAsAlias);
 		args.setParseKotlinMetadata(deobfuscationParseKotlinMetadata);
+		args.setUseKotlinMethodsForVarNames(useKotlinMethodsForVarNames);
 		args.setEscapeUnicode(escapeUnicode);
 		args.setRespectBytecodeAccModifiers(respectBytecodeAccessModifiers);
 		args.setExportAsGradleProject(exportAsGradleProject);
@@ -326,6 +335,10 @@ public class JadxCLIArgs {
 		return deobfuscationParseKotlinMetadata;
 	}
 
+	public UseKotlinMethodsForVarNames getUseKotlinMethodsForVarNames() {
+		return useKotlinMethodsForVarNames;
+	}
+
 	public boolean isEscapeUnicode() {
 		return escapeUnicode;
 	}
@@ -412,9 +425,22 @@ public class JadxCLIArgs {
 		}
 	}
 
+	public static class UseKotlinMethodsForVarNamesConverter implements IStringConverter<UseKotlinMethodsForVarNames> {
+		@Override
+		public UseKotlinMethodsForVarNames convert(String value) {
+			try {
+				return UseKotlinMethodsForVarNames.valueOf(value.replace('-', '_').toUpperCase());
+			} catch (Exception e) {
+				throw new IllegalArgumentException(
+						'\'' + value + "' is unknown, possible values are: "
+								+ JadxCLIArgs.enumValuesString(CommentsLevel.values()));
+			}
+		}
+	}
+
 	public static String enumValuesString(Enum<?>[] values) {
 		return Stream.of(values)
-				.map(v -> v.name().toLowerCase(Locale.ROOT))
+				.map(v -> v.name().replace('_', '-').toLowerCase(Locale.ROOT))
 				.collect(Collectors.joining(", "));
 	}
 }

jadx-core/src/main/java/jadx/api/JadxArgs.java

@@ -87,6 +87,12 @@ public class JadxArgs {
 
 	private boolean useDxInput = false;
 
+	public enum UseKotlinMethodsForVarNames {
+		DISABLE, APPLY, APPLY_AND_HIDE
+	}
+
+	private UseKotlinMethodsForVarNames useKotlinMethodsForVarNames = UseKotlinMethodsForVarNames.APPLY;
+
 	public JadxArgs() {
 		// use default options
 	}
@@ -433,6 +439,14 @@ public class JadxArgs {
 		this.useDxInput = useDxInput;
 	}
 
+	public UseKotlinMethodsForVarNames getUseKotlinMethodsForVarNames() {
+		return useKotlinMethodsForVarNames;
+	}
+
+	public void setUseKotlinMethodsForVarNames(UseKotlinMethodsForVarNames useKotlinMethodsForVarNames) {
+		this.useKotlinMethodsForVarNames = useKotlinMethodsForVarNames;
+	}
+
 	@Override
 	public String toString() {
 		return "JadxArgs{" + "inputFiles=" + inputFiles
@@ -452,6 +466,7 @@ public class JadxArgs {
 				+ ", deobfuscationForceSave=" + deobfuscationForceSave
 				+ ", useSourceNameAsClassAlias=" + useSourceNameAsClassAlias
 				+ ", parseKotlinMetadata=" + parseKotlinMetadata
+				+ ", useKotlinMethodsForVarNames=" + useKotlinMethodsForVarNames
 				+ ", deobfuscationMinLength=" + deobfuscationMinLength
 				+ ", deobfuscationMaxLength=" + deobfuscationMaxLength
 				+ ", escapeUnicode=" + escapeUnicode

jadx-core/src/main/java/jadx/core/Jadx.java

@@ -48,6 +48,7 @@ import jadx.core.dex.visitors.blocks.BlockSplitter;
 import jadx.core.dex.visitors.debuginfo.DebugInfoApplyVisitor;
 import jadx.core.dex.visitors.debuginfo.DebugInfoAttachVisitor;
 import jadx.core.dex.visitors.finaly.MarkFinallyVisitor;
+import jadx.core.dex.visitors.kotlin.ProcessKotlinInternals;
 import jadx.core.dex.visitors.regions.CheckRegions;
 import jadx.core.dex.visitors.regions.CleanRegions;
 import jadx.core.dex.visitors.regions.IfRegionVisitor;
@@ -131,6 +132,9 @@ public class Jadx {
 		if (args.isDebugInfo()) {
 			passes.add(new DebugInfoApplyVisitor());
 		}
+		if (args.getUseKotlinMethodsForVarNames() != JadxArgs.UseKotlinMethodsForVarNames.DISABLE) {
+			passes.add(new ProcessKotlinInternals());
+		}
 		passes.add(new CodeRenameVisitor());
 		if (args.isInlineMethods()) {
 			passes.add(new InlineMethods());

jadx-core/src/main/java/jadx/core/dex/visitors/kotlin/ProcessKotlinInternals.java

@@ -0,0 +1,226 @@
+package jadx.core.dex.visitors.kotlin;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import jadx.api.JadxArgs.UseKotlinMethodsForVarNames;
+import jadx.api.plugins.input.data.attributes.JadxAttrType;
+import jadx.core.deobf.NameMapper;
+import jadx.core.dex.attributes.AFlag;
+import jadx.core.dex.info.ClassInfo;
+import jadx.core.dex.info.FieldInfo;
+import jadx.core.dex.info.MethodInfo;
+import jadx.core.dex.instructions.ConstStringNode;
+import jadx.core.dex.instructions.IndexInsnNode;
+import jadx.core.dex.instructions.InsnType;
+import jadx.core.dex.instructions.InvokeNode;
+import jadx.core.dex.instructions.args.InsnArg;
+import jadx.core.dex.instructions.args.InsnWrapArg;
+import jadx.core.dex.instructions.args.RegisterArg;
+import jadx.core.dex.nodes.BlockNode;
+import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.nodes.FieldNode;
+import jadx.core.dex.nodes.InsnNode;
+import jadx.core.dex.nodes.MethodNode;
+import jadx.core.dex.nodes.RootNode;
+import jadx.core.dex.visitors.AbstractVisitor;
+import jadx.core.dex.visitors.InitCodeVariables;
+import jadx.core.dex.visitors.JadxVisitor;
+import jadx.core.dex.visitors.debuginfo.DebugInfoApplyVisitor;
+import jadx.core.dex.visitors.rename.CodeRenameVisitor;
+import jadx.core.utils.Utils;
+import jadx.core.utils.exceptions.JadxException;
+
+@JadxVisitor(
+		name = "ProcessKotlinInternals",
+		desc = "Use variable names from Kotlin intrinsic1 methods",
+		runAfter = {
+				InitCodeVariables.class,
+				DebugInfoApplyVisitor.class
+		},
+		runBefore = {
+				CodeRenameVisitor.class
+		}
+)
+public class ProcessKotlinInternals extends AbstractVisitor {
+	private static final Logger LOG = LoggerFactory.getLogger(ProcessKotlinInternals.class);
+
+	private static final String KOTLIN_INTERNAL_PKG = "kotlin.jvm.internal.";
+	private static final String KOTLIN_INTRINSICS_CLS = KOTLIN_INTERNAL_PKG + "Intrinsics";
+	private static final String KOTLIN_VARNAME_SOURCE_MTH1 = "(Ljava/lang/Object;Ljava/lang/String;)V";
+	private static final String KOTLIN_VARNAME_SOURCE_MTH2 = "(Ljava/lang/Object;Ljava/lang/String;Ljava/lang/String;)V";
+
+	private @Nullable ClassInfo kotlinIntrinsicsCls;
+	private Set<MethodInfo> kotlinVarNameSourceMethods;
+	private boolean hideInsns;
+
+	@Override
+	public void init(RootNode root) throws JadxException {
+		ClassNode kotlinCls = searchKotlinIntrinsicsClass(root);
+		if (kotlinCls != null) {
+			kotlinIntrinsicsCls = kotlinCls.getClassInfo();
+			kotlinVarNameSourceMethods = collectMethods(kotlinCls);
+			LOG.debug("Kotlin Intrinsics class: {}, methods: {}", kotlinCls, kotlinVarNameSourceMethods.size());
+		} else {
+			kotlinIntrinsicsCls = null;
+			LOG.debug("Kotlin Intrinsics class not found");
+		}
+		hideInsns = root.getArgs().getUseKotlinMethodsForVarNames() == UseKotlinMethodsForVarNames.APPLY_AND_HIDE;
+	}
+
+	@Override
+	public boolean visit(ClassNode cls) {
+		if (kotlinIntrinsicsCls == null) {
+			return false;
+		}
+		for (MethodNode mth : cls.getMethods()) {
+			processMth(mth);
+		}
+		return true;
+	}
+
+	private void processMth(MethodNode mth) {
+		if (mth.isNoCode()) {
+			return;
+		}
+		for (BlockNode block : mth.getBasicBlocks()) {
+			for (InsnNode insn : block.getInstructions()) {
+				if (insn.getType() == InsnType.INVOKE) {
+					try {
+						processInvoke(mth, insn);
+					} catch (Exception e) {
+						mth.addWarnComment("Failed to extract var names", e);
+					}
+				}
+			}
+		}
+	}
+
+	private void processInvoke(MethodNode mth, InsnNode insn) {
+		int argsCount = insn.getArgsCount();
+		if (argsCount < 2) {
+			return;
+		}
+		MethodInfo invokeMth = ((InvokeNode) insn).getCallMth();
+		if (!kotlinVarNameSourceMethods.contains(invokeMth)) {
+			return;
+		}
+		InsnArg firstArg = insn.getArg(0);
+		if (!firstArg.isRegister()) {
+			return;
+		}
+		RegisterArg varArg = (RegisterArg) firstArg;
+		boolean renamed = false;
+		if (argsCount == 2) {
+			String str = getConstString(mth, insn, 1);
+			if (str != null) {
+				renamed = checkAndRename(varArg, str);
+			}
+		} else if (argsCount == 3) {
+			// TODO: use second arg for rename class
+			String str = getConstString(mth, insn, 2);
+			if (str != null) {
+				renamed = checkAndRename(varArg, str);
+			}
+		}
+		if (renamed && hideInsns) {
+			insn.add(AFlag.DONT_GENERATE);
+		}
+	}
+
+	private boolean checkAndRename(RegisterArg arg, String str) {
+		String name = trimName(str);
+		if (NameMapper.isValidAndPrintable(name)) {
+			arg.getSVar().getCodeVar().setName(name);
+			return true;
+		}
+		return false;
+	}
+
+	@Nullable
+	private String getConstString(MethodNode mth, InsnNode insn, int arg) {
+		InsnArg strArg = insn.getArg(arg);
+		if (!strArg.isInsnWrap()) {
+			return null;
+		}
+		InsnNode constInsn = ((InsnWrapArg) strArg).getWrapInsn();
+		InsnType insnType = constInsn.getType();
+		if (insnType == InsnType.CONST_STR) {
+			return ((ConstStringNode) constInsn).getString();
+		}
+		if (insnType == InsnType.SGET) {
+			// revert const field inline :(
+			FieldInfo fieldInfo = (FieldInfo) ((IndexInsnNode) constInsn).getIndex();
+			FieldNode fieldNode = mth.root().resolveField(fieldInfo);
+			if (fieldNode != null) {
+				String str = (String) fieldNode.get(JadxAttrType.CONSTANT_VALUE).getValue();
+				InsnArg newArg = InsnArg.wrapArg(new ConstStringNode(str));
+				insn.replaceArg(strArg, newArg);
+				return str;
+			}
+		}
+		return null;
+	}
+
+	private String trimName(String str) {
+		if (str.startsWith("$this$")) {
+			return str.substring(6);
+		}
+		if (str.startsWith("$")) {
+			return str.substring(1);
+		}
+		return str;
+	}
+
+	@Nullable
+	private static ClassNode searchKotlinIntrinsicsClass(RootNode root) {
+		ClassNode kotlinCls = root.resolveClass(KOTLIN_INTRINSICS_CLS);
+		if (kotlinCls != null) {
+			return kotlinCls;
+		}
+		List<ClassNode> candidates = new ArrayList<>();
+		for (ClassNode cls : root.getClasses()) {
+			if (isKotlinIntrinsicsClass(cls)) {
+				candidates.add(cls);
+			}
+		}
+		return Utils.getOne(candidates);
+	}
+
+	private static boolean isKotlinIntrinsicsClass(ClassNode cls) {
+		if (!cls.getClassInfo().getFullName().startsWith(KOTLIN_INTERNAL_PKG)) {
+			return false;
+		}
+		if (cls.getMethods().size() < 5) {
+			return false;
+		}
+		int mthCount = 0;
+		for (MethodNode mth : cls.getMethods()) {
+			if (mth.getAccessFlags().isStatic()
+					&& mth.getMethodInfo().getShortId().endsWith(KOTLIN_VARNAME_SOURCE_MTH1)) {
+				mthCount++;
+			}
+		}
+		return mthCount > 2;
+	}
+
+	private Set<MethodInfo> collectMethods(ClassNode kotlinCls) {
+		Set<MethodInfo> set = new HashSet<>();
+		for (MethodNode mth : kotlinCls.getMethods()) {
+			if (!mth.getAccessFlags().isStatic()) {
+				continue;
+			}
+			String shortId = mth.getMethodInfo().getShortId();
+			if (shortId.endsWith(KOTLIN_VARNAME_SOURCE_MTH1) || shortId.endsWith(KOTLIN_VARNAME_SOURCE_MTH2)) {
+				set.add(mth.getMethodInfo());
+			}
+		}
+		return set;
+	}
+}

jadx-gui/src/main/java/jadx/gui/settings/JadxSettings.java

@@ -43,7 +43,7 @@ public class JadxSettings extends JadxCLIArgs {
 
 	private static final Path USER_HOME = Paths.get(System.getProperty("user.home"));
 	private static final int RECENT_PROJECTS_COUNT = 15;
-	private static final int CURRENT_SETTINGS_VERSION = 14;
+	private static final int CURRENT_SETTINGS_VERSION = 15;
 
 	private static final Font DEFAULT_FONT = new RSyntaxTextArea().getFont();
 
@@ -338,6 +338,10 @@ public class JadxSettings extends JadxCLIArgs {
 		this.deobfuscationParseKotlinMetadata = deobfuscationParseKotlinMetadata;
 	}
 
+	public void setUseKotlinMethodsForVarNames(JadxArgs.UseKotlinMethodsForVarNames useKotlinMethodsForVarNames) {
+		this.useKotlinMethodsForVarNames = useKotlinMethodsForVarNames;
+	}
+
 	public void updateRenameFlag(JadxArgs.RenameEnum flag, boolean enabled) {
 		if (enabled) {
 			renameFlags.add(flag);
@@ -651,6 +655,10 @@ public class JadxSettings extends JadxCLIArgs {
 			lafTheme = LafManager.INITIAL_THEME_NAME;
 			fromVersion++;
 		}
+		if (fromVersion == 14) {
+			useKotlinMethodsForVarNames = JadxArgs.UseKotlinMethodsForVarNames.APPLY;
+			fromVersion++;
+		}
 		if (fromVersion != CURRENT_SETTINGS_VERSION) {
 			throw new JadxRuntimeException("Incorrect settings upgrade");
 		}

jadx-gui/src/main/java/jadx/gui/settings/JadxSettingsWindow.java

@@ -60,6 +60,7 @@ import say.swing.JFontChooser;
 
 import jadx.api.CommentsLevel;
 import jadx.api.JadxArgs;
+import jadx.api.JadxArgs.UseKotlinMethodsForVarNames;
 import jadx.gui.ui.MainWindow;
 import jadx.gui.ui.codearea.EditorTheme;
 import jadx.gui.utils.FontUtils;
@@ -510,6 +511,13 @@ public class JadxSettingsWindow extends JDialog {
 			needReload();
 		});
 
+		JComboBox<UseKotlinMethodsForVarNames> kotlinRenameVars = new JComboBox<>(UseKotlinMethodsForVarNames.values());
+		kotlinRenameVars.setSelectedItem(settings.getUseKotlinMethodsForVarNames());
+		kotlinRenameVars.addActionListener(e -> {
+			settings.setUseKotlinMethodsForVarNames((UseKotlinMethodsForVarNames) kotlinRenameVars.getSelectedItem());
+			needReload();
+		});
+
 		JComboBox<CommentsLevel> commentsLevel = new JComboBox<>(CommentsLevel.values());
 		commentsLevel.setSelectedItem(settings.getCommentsLevel());
 		commentsLevel.addActionListener(e -> {
@@ -533,6 +541,7 @@ public class JadxSettingsWindow extends JDialog {
 		other.addRow(NLS.str("preferences.fallback"), fallback);
 		other.addRow(NLS.str("preferences.useDx"), useDx);
 		other.addRow(NLS.str("preferences.skipResourcesDecode"), resourceDecode);
+		other.addRow(NLS.str("preferences.useKotlinMethodsForVarNames"), kotlinRenameVars);
 		other.addRow(NLS.str("preferences.commentsLevel"), commentsLevel);
 		return other;
 	}

jadx-gui/src/main/resources/i18n/Messages_de_DE.properties

@@ -134,6 +134,7 @@ preferences.inlineAnonymous=Anonyme Inline-Klassen
 preferences.inlineMethods=Inline-Methoden
 preferences.fsCaseSensitive=Dateisystem unterscheidet zwischen Groß/Kleinschreibung
 preferences.skipResourcesDecode=Keine Ressourcen dekodieren
+#preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 #preferences.commentsLevel=Code comments level
 preferences.autoSave=Autom. speichern
 preferences.threads=Verarbeitungs-Thread-Anzahl

jadx-gui/src/main/resources/i18n/Messages_en_US.properties

@@ -134,6 +134,7 @@ preferences.inlineAnonymous=Inline anonymous classes
 preferences.inlineMethods=Inline methods
 preferences.fsCaseSensitive=File system is case sensitive
 preferences.skipResourcesDecode=Don't decode resources
+preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 preferences.commentsLevel=Code comments level
 preferences.autoSave=Auto save
 preferences.threads=Processing threads count

jadx-gui/src/main/resources/i18n/Messages_es_ES.properties

@@ -134,6 +134,7 @@ preferences.replaceConsts=Reemplazar constantes
 #preferences.inlineMethods=Inline methods
 #preferences.fsCaseSensitive=
 preferences.skipResourcesDecode=No descodificar recursos
+#preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 #preferences.commentsLevel=Code comments level
 #preferences.autoSave=
 preferences.threads=Número de hilos a procesar

jadx-gui/src/main/resources/i18n/Messages_ko_KR.properties

@@ -134,6 +134,7 @@ preferences.inlineAnonymous=인라인 익명 클래스
 preferences.inlineMethods=인라인 메서드
 preferences.fsCaseSensitive=파일 시스템 대소문자 구별
 preferences.skipResourcesDecode=리소스 디코딩 하지 않기
+#preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 preferences.commentsLevel=코드 주석 수준
 preferences.autoSave=자동 저장
 preferences.threads=처리 스레드 수

jadx-gui/src/main/resources/i18n/Messages_zh_CN.properties

@@ -134,6 +134,7 @@ preferences.inlineAnonymous=内联匿名类
 preferences.inlineMethods=内联方法
 preferences.fsCaseSensitive=文件系统区分大小写
 preferences.skipResourcesDecode=不反编译资源文件
+#preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 preferences.commentsLevel=代码注释等级
 preferences.autoSave=自动保存
 preferences.threads=并行线程数

jadx-gui/src/main/resources/i18n/Messages_zh_TW.properties

@@ -134,11 +134,12 @@ preferences.inlineAnonymous=內嵌匿名類別
 preferences.inlineMethods=內嵌方式
 preferences.fsCaseSensitive=檔案系統區分大小寫
 preferences.skipResourcesDecode=不要為資源解碼
+#preferences.useKotlinMethodsForVarNames=Use kotlin methods for variables rename
 preferences.commentsLevel=程式碼註解層級
 preferences.autoSave=自動儲存
 preferences.threads=執行緒數
 preferences.excludedPackages=被排除的套件
-preferences.excludedPackages.tooltip=排除於索引或反編譯外的套件列表 (以空格分隔) (節省 RAM) 
+preferences.excludedPackages.tooltip=排除於索引或反編譯外的套件列表 (以空格分隔) (節省 RAM)
 preferences.excludedPackages.button=編輯
 preferences.excludedPackages.editDialog=<html>排除於索引或反編譯外的套件列表 (以空格分隔) (節省 RAM) <br>例如 <code>android.support</code></html>
 preferences.cfg=產生方法 CFG 圖表 ('dot' 格式)