core: fix catch block argument if move-exception instruction is missing (#295)

jadx-core/src/main/java/jadx/core/dex/visitors/blocksmaker/BlockExceptionHandler.java

 package jadx.core.dex.visitors.blocksmaker;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.attributes.AType;
 import jadx.core.dex.instructions.InsnType;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
+import jadx.core.dex.instructions.args.NamedArg;
 import jadx.core.dex.instructions.args.RegisterArg;
 import jadx.core.dex.nodes.BlockNode;
 import jadx.core.dex.nodes.InsnNode;
@@ -19,6 +23,8 @@ import jadx.core.utils.InstructionRemover;
 
 public class BlockExceptionHandler extends AbstractVisitor {
 
+	private static final Logger LOG = LoggerFactory.getLogger(BlockExceptionHandler.class);
+
 	@Override
 	public void visit(MethodNode mth) {
 		if (mth.isNoCode()) {
@@ -47,20 +53,22 @@ public class BlockExceptionHandler extends AbstractVisitor {
 		}
 		InsnNode me = block.getInstructions().get(0);
 		ExcHandlerAttr handlerAttr = me.get(AType.EXC_HANDLER);
-		if (handlerAttr == null || me.getType() != InsnType.MOVE_EXCEPTION) {
+		if (handlerAttr == null) {
 			return;
 		}
 		ExceptionHandler excHandler = handlerAttr.getHandler();
 		block.addAttr(handlerAttr);
-		// set correct type for 'move-exception' operation
-		ArgType type = excHandler.isCatchAll() ? ArgType.THROWABLE : excHandler.getCatchType().getType();
-
-		RegisterArg resArg = me.getResult();
-		resArg = InsnArg.reg(resArg.getRegNum(), type);
-		me.setResult(resArg);
-		me.add(AFlag.DONT_INLINE);
-
-		excHandler.setArg(resArg);
+		ArgType argType = excHandler.isCatchAll() ? ArgType.THROWABLE : excHandler.getCatchType().getType();
+		if (me.getType() == InsnType.MOVE_EXCEPTION) {
+			// set correct type for 'move-exception' operation
+			RegisterArg resArg = InsnArg.reg(me.getResult().getRegNum(), argType);
+			me.setResult(resArg);
+			me.add(AFlag.DONT_INLINE);
+			excHandler.setArg(resArg);
+		} else {
+			// handler arguments not used
+			excHandler.setArg(new NamedArg("unused", argType));
+		}
 	}
 
 	private static void processExceptionHandlers(MethodNode mth, BlockNode block) {
@@ -147,5 +155,8 @@ public class BlockExceptionHandler extends AbstractVisitor {
 				break;
 			}
 		}
+		if (handler.getHandlerBlock() == null) {
+			LOG.warn("Exception handler block not set for {}, mth: {}", handler, mth);
+		}
 	}
 }

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

@@ -86,8 +86,7 @@ public class ProcessTryCatchRegions extends AbstractRegionVisitor {
 			if (domBlocks.size() != 1) {
 				domBlock = BlockUtils.getTopBlock(domBlocks);
 				if (domBlock == null) {
-					throw new JadxRuntimeException(
-							"Exception block dominator not found, method:" + mth + ". bs: " + domBlocks);
+					throw new JadxRuntimeException("Exception block dominator not found, method:" + mth + ", dom blocks: " + domBlocks);
 				}
 			} else {
 				domBlock = domBlocks.get(0);