Remove unneeded 'return' instructions

src/main/java/jadx/dex/nodes/MethodNode.java

@@ -4,6 +4,7 @@ import jadx.Consts;
 import jadx.dex.attributes.AttrNode;
 import jadx.dex.attributes.AttributeFlag;
 import jadx.dex.attributes.JumpAttribute;
+import jadx.dex.attributes.LoopAttr;
 import jadx.dex.attributes.annotations.Annotation;
 import jadx.dex.info.AccessInfo;
 import jadx.dex.info.AccessInfo.AFType;
@@ -64,6 +65,7 @@ public class MethodNode extends AttrNode implements ILoadable {
 
 	private IContainer region;
 	private List<ExceptionHandler> exceptionHandlers;
+	private List<LoopAttr> loops = Collections.emptyList();
 
 	public MethodNode(ClassNode classNode, Method mthData) {
 		this.mthInfo = MethodInfo.fromDex(classNode.dex(), mthData.getMethodIndex());
@@ -411,6 +413,21 @@ public class MethodNode extends AttrNode implements ILoadable {
 		this.exitBlocks.add(exitBlock);
 	}
 
+	public void registerLoop(LoopAttr loop) {
+		if(loops.isEmpty()) {
+			loops = new ArrayList<LoopAttr>(5);
+		}
+		loops.add(loop);
+	}
+
+	public LoopAttr getLoopForBlock(BlockNode block) {
+		for (LoopAttr loop : loops) {
+			if(loop.getLoopBlocks().contains(block))
+				return loop;
+		}
+		return null;
+	}
+
 	public ExceptionHandler addExceptionHandler(ExceptionHandler handler) {
 		if (exceptionHandlers == null) {
 			exceptionHandlers = new ArrayList<ExceptionHandler>(2);

src/main/java/jadx/dex/visitors/BlockMakerVisitor.java

@@ -180,6 +180,8 @@ public class BlockMakerVisitor extends AbstractVisitor {
 			if (i > 100)
 				throw new AssertionError("Can't fix method cfg: " + mth);
 		}
+
+		registerLoops(mth);
 	}
 
 	private static BlockNode getBlock(int offset, Map<Integer, BlockNode> blocksMap) {
@@ -307,6 +309,16 @@ public class BlockMakerVisitor extends AbstractVisitor {
 		}
 	}
 
+	private static void registerLoops(MethodNode mth) {
+		for (BlockNode block : mth.getBasicBlocks()) {
+			AttributesList attributes = block.getAttributes();
+			IAttribute loop = attributes.get(AttributeType.LOOP);
+			if(loop != null && attributes.contains(AttributeFlag.LOOP_START)) {
+				mth.registerLoop((LoopAttr) loop);
+			}
+		}
+	}
+
 	private static boolean modifyBlocksTree(MethodNode mth) {
 		for (BlockNode block : mth.getBasicBlocks()) {
 			if (block.getPredecessors().isEmpty() && block != mth.getEnterBlock()) {

src/main/java/jadx/dex/visitors/regions/FinishRegions.java

 package jadx.dex.visitors.regions;
 
 import jadx.dex.instructions.InsnType;
+import jadx.dex.instructions.args.ArgType;
+import jadx.dex.nodes.BlockNode;
 import jadx.dex.nodes.IBlock;
 import jadx.dex.nodes.IRegion;
 import jadx.dex.nodes.InsnNode;
 import jadx.dex.nodes.MethodNode;
 import jadx.dex.regions.LoopRegion;
 
+import java.util.Iterator;
 import java.util.List;
 
-public class FinishRegions implements IRegionVisitor {
-
+public class FinishRegions extends TracedRegionVisitor {
 	@Override
-	public void processBlock(MethodNode mth, IBlock block) {
+	public void processBlockTraced(MethodNode mth, IBlock container, IRegion currentRegion) {
+		if (container.getClass() != BlockNode.class)
+			return;
+
+		BlockNode block = (BlockNode) container;
 
-		// remove return from class init method
-		if (mth.getMethodInfo().isClassInit()) {
+		// remove last return in void functions
+		if (block.getCleanSuccessors().isEmpty()
+				&& mth.getReturnType().equals(ArgType.VOID)) {
 			List<InsnNode> insns = block.getInstructions();
-			if (insns.size() != 0) {
-				InsnNode last = insns.get(insns.size() - 1);
-				if (last.getType() == InsnType.RETURN) {
-					insns.remove(insns.size() - 1);
+			int lastIndex = insns.size() - 1;
+			if (lastIndex != -1) {
+				InsnNode last = insns.get(lastIndex);
+				if (last.getType() == InsnType.RETURN
+						&& blockNotInLoop(mth, block)) {
+					insns.remove(lastIndex);
 				}
 			}
 		}
 	}
 
-	@Override
-	public void enterRegion(MethodNode mth, IRegion region) {
+	private boolean blockNotInLoop(MethodNode mth, BlockNode block) {
+		if (mth.getLoopForBlock(block) != null)
+			return false;
+
+		for (Iterator<IRegion> it = regionStack.descendingIterator(); it.hasNext(); ) {
+			IRegion region = it.next();
+			if (region.getClass() == LoopRegion.class)
+				return false;
+		}
+		return true;
 	}
 
 	@Override
@@ -36,6 +53,6 @@ public class FinishRegions implements IRegionVisitor {
 			LoopRegion loop = (LoopRegion) region;
 			loop.mergePreCondition();
 		}
+		super.leaveRegion(mth, region);
 	}
-
 }

src/main/java/jadx/dex/visitors/regions/TracedRegionVisitor.java

@@ -4,11 +4,12 @@ import jadx.dex.nodes.IBlock;
 import jadx.dex.nodes.IRegion;
 import jadx.dex.nodes.MethodNode;
 
-import java.util.Stack;
+import java.util.ArrayDeque;
+import java.util.Deque;
 
 public abstract class TracedRegionVisitor implements IRegionVisitor {
 
-	private final Stack<IRegion> regionStack = new Stack<IRegion>();
+	protected final Deque<IRegion> regionStack = new ArrayDeque<IRegion>();
 
 	@Override
 	public void enterRegion(MethodNode mth, IRegion region) {
@@ -27,5 +28,4 @@ public abstract class TracedRegionVisitor implements IRegionVisitor {
 	public void leaveRegion(MethodNode mth, IRegion region) {
 		regionStack.pop();
 	}
-
 }