core: make decompilation results more deterministic

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

 package jadx.core;
 
+import java.util.List;
+
+import org.jetbrains.annotations.Nullable;
+
 import jadx.core.codegen.CodeGen;
 import jadx.core.dex.nodes.ClassNode;
 import jadx.core.dex.visitors.DepthTraversal;
 import jadx.core.dex.visitors.IDexTreeVisitor;
 import jadx.core.utils.ErrorsCounter;
 
-import java.util.List;
-
-import org.jetbrains.annotations.Nullable;
-
 import static jadx.core.dex.nodes.ProcessState.GENERATED;
 import static jadx.core.dex.nodes.ProcessState.NOT_LOADED;
 import static jadx.core.dex.nodes.ProcessState.PROCESSED;
@@ -25,7 +25,7 @@ public final class ProcessClass {
 		if (codeGen == null && cls.getState() == PROCESSED) {
 			return;
 		}
-		synchronized (cls.getClassInfo()) {
+		synchronized (getSyncObj(cls)) {
 			try {
 				if (cls.getState() == NOT_LOADED) {
 					cls.load();
@@ -51,6 +51,10 @@ public final class ProcessClass {
 		}
 	}
 
+	public static Object getSyncObj(ClassNode cls) {
+		return cls.getClassInfo();
+	}
+
 	private static void processDependencies(ClassNode cls, List<IDexTreeVisitor> passes) {
 		for (ClassNode depCls : cls.getDependencies()) {
 			process(depCls, passes, null);

jadx-core/src/main/java/jadx/core/codegen/CodeWriter.java

@@ -254,8 +254,9 @@ public class CodeWriter {
 	}
 
 	private void removeFirstEmptyLine() {
-		if (buf.indexOf(NL) == 0) {
-			buf.delete(0, NL.length());
+		int len = NL.length();
+		if (buf.substring(0, len).equals(NL)) {
+			buf.delete(0, len);
 		}
 	}
 

jadx-core/src/main/java/jadx/core/codegen/NameGen.java

@@ -19,6 +19,7 @@ import jadx.core.utils.StringUtils;
 
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
 
@@ -26,7 +27,7 @@ public class NameGen {
 
 	private static final Map<String, String> OBJ_ALIAS;
 
-	private final Set<String> varNames = new HashSet<>();
+	private final Set<String> varNames = new LinkedHashSet<>();
 	private final MethodNode mth;
 	private final boolean fallback;
 

jadx-core/src/main/java/jadx/core/dex/instructions/PhiInsn.java

@@ -11,6 +11,7 @@ import jadx.core.utils.Utils;
 import jadx.core.utils.exceptions.JadxRuntimeException;
 
 import java.util.IdentityHashMap;
+import java.util.LinkedHashMap;
 import java.util.Map;
 
 import org.jetbrains.annotations.NotNull;
@@ -21,7 +22,7 @@ public final class PhiInsn extends InsnNode {
 
 	public PhiInsn(int regNum, int predecessors) {
 		super(InsnType.PHI, predecessors);
-		this.blockBinds = new IdentityHashMap<>(predecessors);
+		this.blockBinds = new LinkedHashMap<>(predecessors);
 		setResult(InsnArg.reg(regNum, ArgType.UNKNOWN));
 		add(AFlag.DONT_INLINE);
 	}

jadx-core/src/main/java/jadx/core/dex/regions/conditions/IfInfo.java

@@ -16,7 +16,7 @@ public final class IfInfo {
 	private BlockNode ifBlock;
 
 	public IfInfo(IfCondition condition, BlockNode thenBlock, BlockNode elseBlock) {
-		this(condition, thenBlock, elseBlock, new HashSet<BlockNode>(), new HashSet<BlockNode>());
+		this(condition, thenBlock, elseBlock, new HashSet<>(), new HashSet<>());
 	}
 
 	public IfInfo(IfInfo info, BlockNode thenBlock, BlockNode elseBlock) {

jadx-core/src/main/java/jadx/core/dex/visitors/ReSugarCode.java

 package jadx.core.dex.visitors;
 
+import jadx.core.ProcessClass;
 import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.attributes.AType;
 import jadx.core.dex.attributes.nodes.EnumMapAttr;
@@ -141,7 +142,6 @@ public class ReSugarCode extends AbstractVisitor {
 		}
 		enumMapField.add(AFlag.DONT_GENERATE);
 		checkAndHideClass(enumMapField.getParentClass());
-		return;
 	}
 
 	private static EnumMapAttr.KeyValueMap getEnumMap(MethodNode mth, FieldNode field) {
@@ -150,6 +150,7 @@ public class ReSugarCode extends AbstractVisitor {
 		if (mapAttr != null) {
 			return mapAttr.getMap(field);
 		}
+		synchronized (ProcessClass.getSyncObj(syntheticClass)) {
 			mapAttr = new EnumMapAttr();
 			syntheticClass.addAttr(mapAttr);
 
@@ -178,6 +179,7 @@ public class ReSugarCode extends AbstractVisitor {
 			}
 			return mapAttr.getMap(field);
 		}
+	}
 
 	private static void addToEnumMap(MethodNode mth, EnumMapAttr mapAttr, InsnNode aputInsn) {
 		InsnArg litArg = aputInsn.getArg(2);

jadx-core/src/main/java/jadx/core/dex/visitors/SaveCode.java

@@ -4,6 +4,7 @@ import java.io.File;
 
 import jadx.api.JadxArgs;
 import jadx.core.codegen.CodeWriter;
+import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.nodes.ClassNode;
 
 public class SaveCode {
@@ -11,6 +12,9 @@ public class SaveCode {
 	private SaveCode() {}
 
 	public static void save(File dir, JadxArgs args, ClassNode cls) {
+		if (cls.contains(AFlag.DONT_GENERATE)) {
+			return;
+		}
 		CodeWriter clsCode = cls.getCode();
 		String fileName = cls.getClassInfo().getFullPath() + ".java";
 		if (args.isFallbackMode()) {

jadx-core/src/main/java/jadx/core/dex/visitors/regions/ProcessVariables.java

@@ -25,6 +25,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -72,8 +73,8 @@ public class ProcessVariables extends AbstractVisitor {
 		private RegisterArg arg;
 		private VarName varName;
 		private IRegion argRegion;
-		private final Set<IRegion> usage = new HashSet<>(2);
-		private final Set<IRegion> assigns = new HashSet<>(2);
+		private final Set<IRegion> usage = new LinkedHashSet<>(2);
+		private final Set<IRegion> assigns = new LinkedHashSet<>(2);
 
 		public void setArg(RegisterArg arg) {
 			this.arg = arg;