core: fix type inference and const inline for arrays

jadx-core/src/main/java/jadx/core/dex/attributes/AFlag.java

@@ -15,6 +15,7 @@ public enum AFlag {
 	DONT_WRAP,
 
 	DONT_SHRINK,
+	DONT_INLINE,
 	DONT_GENERATE,
 	SKIP,
 

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

@@ -9,6 +9,7 @@ import jadx.core.dex.instructions.args.RegisterArg;
 import jadx.core.dex.nodes.DexNode;
 import jadx.core.dex.nodes.InsnNode;
 import jadx.core.dex.nodes.MethodNode;
+import jadx.core.utils.InsnUtils;
 import jadx.core.utils.exceptions.DecodeException;
 
 import com.android.dex.Code;
@@ -620,16 +621,19 @@ public class InsnDecoder {
 		int resReg = getMoveResultRegister(insnArr, offset);
 		ArgType arrType = dex.getType(insn.getIndex());
 		ArgType elType = arrType.getArrayElement();
-		InsnArg[] regs = new InsnArg[insn.getRegisterCount()];
+		boolean typeImmutable = elType.isPrimitive();
+		int regsCount = insn.getRegisterCount();
+		InsnArg[] regs = new InsnArg[regsCount];
 		if (isRange) {
 			int r = insn.getA();
-			for (int i = 0; i < insn.getRegisterCount(); i++) {
-				regs[i] = InsnArg.reg(r, elType);
+			for (int i = 0; i < regsCount; i++) {
+				regs[i] = InsnArg.reg(r, elType, typeImmutable);
 				r++;
 			}
 		} else {
-			for (int i = 0; i < insn.getRegisterCount(); i++) {
-				regs[i] = InsnArg.reg(insn, i, elType);
+			for (int i = 0; i < regsCount; i++) {
+				int regNum = InsnUtils.getArg(insn, i);
+				regs[i] = InsnArg.reg(regNum, elType, typeImmutable);
 			}
 		}
 		return insn(InsnType.FILLED_NEW_ARRAY,

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

 package jadx.core.dex.instructions;
 
+import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.RegisterArg;
@@ -14,6 +15,7 @@ public class PhiInsn extends InsnNode {
 		for (int i = 0; i < predecessors; i++) {
 			addReg(regNum, ArgType.UNKNOWN);
 		}
+		add(AFlag.DONT_INLINE);
 	}
 
 	@Override

jadx-core/src/main/java/jadx/core/dex/instructions/args/ArgType.java

@@ -9,6 +9,8 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.jetbrains.annotations.Nullable;
+
 public abstract class ArgType {
 
 	public static final ArgType INT = primitive(PrimitiveType.INT);
@@ -93,10 +95,28 @@ public abstract class ArgType {
 	}
 
 	private abstract static class KnownType extends ArgType {
+
+		private static final PrimitiveType[] EMPTY_POSSIBLES = new PrimitiveType[0];
+
 		@Override
 		public boolean isTypeKnown() {
 			return true;
 		}
+
+		@Override
+		public boolean contains(PrimitiveType type) {
+			return getPrimitiveType() == type;
+		}
+
+		@Override
+		public ArgType selectFirst() {
+			return null;
+		}
+
+		@Override
+		public PrimitiveType[] getPossibleTypes() {
+			return EMPTY_POSSIBLES;
+		}
 	}
 
 	private static final class PrimitiveArg extends KnownType {
@@ -269,6 +289,7 @@ public abstract class ArgType {
 	}
 
 	private static final class ArrayArg extends KnownType {
+		public static final PrimitiveType[] ARRAY_POSSIBLES = new PrimitiveType[]{PrimitiveType.ARRAY};
 		private final ArgType arrayElement;
 
 		public ArrayArg(ArgType arrayElement) {
@@ -292,6 +313,21 @@ public abstract class ArgType {
 		}
 
 		@Override
+		public boolean isTypeKnown() {
+			return arrayElement.isTypeKnown();
+		}
+
+		@Override
+		public ArgType selectFirst() {
+			return array(arrayElement.selectFirst());
+		}
+
+		@Override
+		public PrimitiveType[] getPossibleTypes() {
+			return ARRAY_POSSIBLES;
+		}
+
+		@Override
 		public int getArrayDimension() {
 			return 1 + arrayElement.getArrayDimension();
 		}
@@ -343,8 +379,10 @@ public abstract class ArgType {
 		@Override
 		public ArgType selectFirst() {
 			PrimitiveType f = possibleTypes[0];
-			if (f == PrimitiveType.OBJECT || f == PrimitiveType.ARRAY) {
-				return object(Consts.CLASS_OBJECT);
+			if (contains(PrimitiveType.OBJECT)) {
+				return OBJECT;
+			} else if (contains(PrimitiveType.ARRAY)) {
+				return array(OBJECT);
 			} else {
 				return primitive(f);
 			}
@@ -428,18 +466,13 @@ public abstract class ArgType {
 		return this;
 	}
 
-	public boolean contains(PrimitiveType type) {
-		throw new UnsupportedOperationException();
-	}
+	public abstract boolean contains(PrimitiveType type);
 
-	public ArgType selectFirst() {
-		throw new UnsupportedOperationException();
-	}
+	public abstract ArgType selectFirst();
 
-	public PrimitiveType[] getPossibleTypes() {
-		return null;
-	}
+	public abstract PrimitiveType[] getPossibleTypes();
 
+	@Nullable
 	public static ArgType merge(ArgType a, ArgType b) {
 		if (a == null || b == null) {
 			return null;
@@ -458,13 +491,18 @@ public abstract class ArgType {
 		if (a == UNKNOWN) {
 			return b;
 		}
+
+		if (a.isArray()) {
+			return mergeArrays((ArrayArg) a, b);
+		} else if (b.isArray()) {
+			return mergeArrays((ArrayArg) b, a);
+		}
 		if (!a.isTypeKnown()) {
 			if (b.isTypeKnown()) {
 				if (a.contains(b.getPrimitiveType())) {
 					return b;
-				} else {
-					return null;
 				}
+				return null;
 			} else {
 				// both types unknown
 				List<PrimitiveType> types = new ArrayList<PrimitiveType>();
@@ -475,7 +513,8 @@ public abstract class ArgType {
 				}
 				if (types.isEmpty()) {
 					return null;
-				} else if (types.size() == 1) {
+				}
+				if (types.size() == 1) {
 					PrimitiveType nt = types.get(0);
 					if (nt == PrimitiveType.OBJECT || nt == PrimitiveType.ARRAY) {
 						return unknown(nt);
@@ -499,35 +538,38 @@ public abstract class ArgType {
 				String bObj = b.getObject();
 				if (aObj.equals(bObj)) {
 					return a.getGenericTypes() != null ? a : b;
-				} else if (aObj.equals(Consts.CLASS_OBJECT)) {
+				}
+				if (aObj.equals(Consts.CLASS_OBJECT)) {
 					return b;
-				} else if (bObj.equals(Consts.CLASS_OBJECT)) {
+				}
+				if (bObj.equals(Consts.CLASS_OBJECT)) {
 					return a;
-				} else {
-					// different objects
+				}
 				String obj = clsp.getCommonAncestor(aObj, bObj);
 				return obj == null ? null : object(obj);
 			}
+			if (a.isPrimitive() && b.isPrimitive() && a.getRegCount() == b.getRegCount()) {
+				return primitive(PrimitiveType.getSmaller(a.getPrimitiveType(), b.getPrimitiveType()));
+			}
 		}
-			if (a.isArray()) {
+		return null;
+	}
+
+	private static ArgType mergeArrays(ArrayArg array, ArgType b) {
 		if (b.isArray()) {
-					ArgType ea = a.getArrayElement();
+			ArgType ea = array.getArrayElement();
 			ArgType eb = b.getArrayElement();
 			if (ea.isPrimitive() && eb.isPrimitive()) {
 				return OBJECT;
-					} else {
+			}
 			ArgType res = merge(ea, eb);
 			return res == null ? null : array(res);
 		}
-				} else if (b.equals(OBJECT)) {
-					return OBJECT;
-				} else {
-					return null;
-				}
-			}
-			if (a.isPrimitive() && b.isPrimitive() && a.getRegCount() == b.getRegCount()) {
-				return primitive(PrimitiveType.getSmaller(a.getPrimitiveType(), b.getPrimitiveType()));
+		if (b.contains(PrimitiveType.ARRAY)) {
+			return array;
 		}
+		if (b.equals(OBJECT)) {
+			return OBJECT;
 		}
 		return null;
 	}

jadx-core/src/main/java/jadx/core/dex/instructions/args/InsnArg.java

@@ -34,6 +34,10 @@ public abstract class InsnArg extends Typed {
 		return new TypeImmutableArg(regNum, type);
 	}
 
+	public static RegisterArg reg(int regNum, ArgType type, boolean typeImmutable) {
+		return typeImmutable ? new TypeImmutableArg(regNum, type) : new RegisterArg(regNum, type);
+	}
+
 	public static LiteralArg lit(long literal, ArgType type) {
 		return new LiteralArg(literal, type);
 	}

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

 package jadx.core.dex.visitors;
 
+import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.attributes.AType;
 import jadx.core.dex.instructions.IfNode;
 import jadx.core.dex.instructions.InsnType;
@@ -59,6 +60,7 @@ public class BlockProcessingHelper {
 		RegisterArg resArg = me.getResult();
 		resArg = InsnArg.reg(resArg.getRegNum(), type);
 		me.setResult(resArg);
+		me.add(AFlag.DONT_INLINE);
 
 		excHandler.setArg(resArg);
 	}

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

@@ -2,7 +2,6 @@ package jadx.core.dex.visitors;
 
 import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.instructions.InsnType;
-import jadx.core.dex.instructions.PhiInsn;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.InsnWrapArg;
 import jadx.core.dex.instructions.args.RegisterArg;
@@ -213,9 +212,7 @@ public class CodeShrinker extends AbstractVisitor {
 					continue;
 				}
 				InsnNode assignInsn = sVar.getAssign().getParentInsn();
-				if (assignInsn == null
-						|| assignInsn instanceof PhiInsn
-						|| assignInsn.getType() == InsnType.MOVE_EXCEPTION) {
+				if (assignInsn == null || assignInsn.contains(AFlag.DONT_INLINE)) {
 					continue;
 				}
 				int assignPos = insnList.getIndex(assignInsn);

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

 package jadx.core.dex.visitors;
 
+import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.info.FieldInfo;
 import jadx.core.dex.instructions.IndexInsnNode;
 import jadx.core.dex.instructions.InsnType;
@@ -52,21 +53,13 @@ public class ConstInlinerVisitor extends AbstractVisitor {
 
 		SSAVar sVar = insn.getResult().getSVar();
 		if (lit == 0) {
-			// don't inline null object if:
-			// - used as instance arg in invoke instruction
-			for (RegisterArg useArg : sVar.getUseList()) {
-				InsnNode parentInsn = useArg.getParentInsn();
-				if (parentInsn != null) {
-					InsnType insnType = parentInsn.getType();
-					if (insnType == InsnType.INVOKE) {
-						InvokeNode inv = (InvokeNode) parentInsn;
-						if (inv.getInvokeType() != InvokeType.STATIC
-								&& inv.getArg(0) == useArg) {
-							return false;
-						}
-					}
+			if (checkObjectInline(sVar)) {
+				if (sVar.getUseCount() == 1) {
+					insn.getResult().getAssignInsn().add(AFlag.DONT_INLINE);
 				}
+				return false;
 			}
+
 		}
 		ArgType resType = insn.getResult().getType();
 		// make sure arg has correct type
@@ -76,6 +69,32 @@ public class ConstInlinerVisitor extends AbstractVisitor {
 		return replaceConst(mth, sVar, lit);
 	}
 
+	/**
+	 * Don't inline null object if:
+	 * - used as instance arg in invoke instruction
+	 * - used in 'array.length'
+	 */
+	private static boolean checkObjectInline(SSAVar sVar) {
+		for (RegisterArg useArg : sVar.getUseList()) {
+			InsnNode insn = useArg.getParentInsn();
+			if (insn != null) {
+				InsnType insnType = insn.getType();
+				if (insnType == InsnType.INVOKE) {
+					InvokeNode inv = (InvokeNode) insn;
+					if (inv.getInvokeType() != InvokeType.STATIC
+							&& inv.getArg(0) == useArg) {
+						return true;
+					}
+				} else if (insnType == InsnType.ARRAY_LENGTH) {
+					if (insn.getArg(0) == useArg) {
+						return true;
+					}
+				}
+			}
+		}
+		return false;
+	}
+
 	private static boolean replaceConst(MethodNode mth, SSAVar sVar, long literal) {
 		List<RegisterArg> use = new ArrayList<RegisterArg>(sVar.getUseList());
 		int replaceCount = 0;

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

@@ -107,7 +107,7 @@ public class LoopRegionVisitor extends AbstractVisitor implements IRegionVisitor
 		List<RegisterArg> args = new LinkedList<RegisterArg>();
 		incrInsn.getRegisterArgs(args);
 		for (RegisterArg iArg : args) {
-			if (assignOnlyInLoop(mth, loopRegion, (RegisterArg) iArg)) {
+			if (assignOnlyInLoop(mth, loopRegion, iArg)) {
 				return false;
 			}
 		}

jadx-core/src/main/java/jadx/core/utils/ErrorsCounter.java

@@ -40,7 +40,7 @@ public class ErrorsCounter {
 			if (e.getClass() == JadxOverflowException.class) {
 				// don't print full stack trace
 				e = new JadxOverflowException(e.getMessage());
-				LOG.error(msg);
+				LOG.error(msg + ", message: " + e.getMessage());
 			} else {
 				LOG.error(msg, e);
 			}

jadx-core/src/main/java/jadx/core/utils/InsnUtils.java

@@ -35,11 +35,7 @@ public class InsnUtils {
 	}
 
 	public static String insnTypeToString(InsnType type) {
-		return insnTypeToString(type.toString());
-	}
-
-	public static String insnTypeToString(String str) {
-		return String.format("%s  ", str);
+		return type.toString() + "  ";
 	}
 
 	public static String indexToString(Object index) {
@@ -49,7 +45,7 @@ public class InsnUtils {
 		if (index instanceof String) {
 			return "\"" + index + "\"";
 		} else {
-			return " " + index;
+			return index.toString();
 		}
 	}
 }

jadx-core/src/test/java/jadx/tests/api/IntegrationTest.java

@@ -201,6 +201,7 @@ public abstract class IntegrationTest extends TestUtils {
 			dynamicCompiler = new DynamicCompiler(cls);
 			boolean result = dynamicCompiler.compile();
 			assertTrue("Compilation failed", result);
+			System.out.println("Compilation: PASSED");
 		} catch (Exception e) {
 			e.printStackTrace();
 			fail(e.getMessage());

jadx-core/src/test/java/jadx/tests/functional/TypeMergeTest.java

@@ -20,6 +20,7 @@ import static jadx.core.dex.instructions.args.ArgType.OBJECT;
 import static jadx.core.dex.instructions.args.ArgType.STRING;
 import static jadx.core.dex.instructions.args.ArgType.UNKNOWN;
 import static jadx.core.dex.instructions.args.ArgType.UNKNOWN_OBJECT;
+import static jadx.core.dex.instructions.args.ArgType.array;
 import static jadx.core.dex.instructions.args.ArgType.genericType;
 import static jadx.core.dex.instructions.args.ArgType.object;
 import static jadx.core.dex.instructions.args.ArgType.unknown;
@@ -59,13 +60,6 @@ public class TypeMergeTest {
 				unknown(PrimitiveType.OBJECT, PrimitiveType.ARRAY),
 				unknown(PrimitiveType.OBJECT));
 
-		check(ArgType.array(INT), ArgType.array(BYTE), ArgType.OBJECT);
-		first(ArgType.array(INT), ArgType.array(INT));
-		first(ArgType.array(STRING), ArgType.array(STRING));
-
-		first(OBJECT, ArgType.array(INT));
-		first(OBJECT, ArgType.array(STRING));
-
 		ArgType objExc = object("java.lang.Exception");
 		ArgType objThr = object("java.lang.Throwable");
 		ArgType objIO = object("java.io.IOException");
@@ -83,6 +77,18 @@ public class TypeMergeTest {
 		first(generic, objExc);
 	}
 
+	@Test
+	public void testArrayMerge() {
+		check(array(INT), array(BYTE), ArgType.OBJECT);
+		first(array(INT), array(INT));
+		first(array(STRING), array(STRING));
+
+		first(OBJECT, array(INT));
+		first(OBJECT, array(STRING));
+
+		first(array(unknown(PrimitiveType.INT, PrimitiveType.FLOAT)), unknown(PrimitiveType.ARRAY));
+	}
+
 	private void first(ArgType t1, ArgType t2) {
 		check(t1, t2, t1);
 	}

jadx-core/src/test/java/jadx/tests/integration/TestWrongCode.java

@@ -5,6 +5,7 @@ import jadx.tests.api.IntegrationTest;
 
 import org.junit.Test;
 
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.not;
 import static org.junit.Assert.assertThat;
@@ -28,13 +29,19 @@ public class TestWrongCode extends IntegrationTest {
 
 	@Test
 	public void test() {
-		disableCompilation();
 		ClassNode cls = getClassNode(TestCls.class);
 		String code = cls.getCode().toString();
 
 		assertThat(code, not(containsString("return false.length;")));
-		assertThat(code, containsString("return null.length;"));
+		assertThat(code, containsOne("int[] a = null;"));
+		assertThat(code, containsOne("return a.length;"));
 
 		assertThat(code, containsString("return a == 0 ? a : a;"));
 	}
+
+	@Test
+	public void testNoDebug() {
+		noDebugInfo();
+		getClassNode(TestCls.class);
+	}
 }

jadx-core/src/test/java/jadx/tests/integration/arrays/TestArrays.java

+package jadx.tests.integration.arrays;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+import org.junit.Test;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.junit.Assert.assertThat;
+
+public class TestArrays extends IntegrationTest {
+	public static class TestCls {
+
+		public int test1(int i) {
+			int[] a = new int[]{1, 2, 3, 5};
+			return a[i];
+		}
+
+		public int test2(int i) {
+			int[][] a = new int[i][i + 1];
+			return a.length;
+		}
+	}
+
+	@Test
+	public void test() {
+		noDebugInfo();
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsOne("return new int[]{1, 2, 3, 5}[i];"));
+	}
+}