core: check arguments for field arithmetic operations (fix #40)

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

@@ -2,14 +2,17 @@ package jadx.core.dex.instructions.args;
 
 import jadx.core.dex.info.FieldInfo;
 
+import org.jetbrains.annotations.Nullable;
+
 // TODO: don't extend RegisterArg (now used as a result of instruction)
 public final class FieldArg extends RegisterArg {
 
 	private final FieldInfo field;
 	// instArg equal 'null' for static fields
+	@Nullable
 	private final InsnArg instArg;
 
-	public FieldArg(FieldInfo field, InsnArg reg) {
+	public FieldArg(FieldInfo field, @Nullable InsnArg reg) {
 		super(-1);
 		this.instArg = reg;
 		this.field = field;

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

@@ -2,11 +2,13 @@ package jadx.core.dex.instructions.args;
 
 import jadx.core.dex.nodes.InsnNode;
 
+import org.jetbrains.annotations.NotNull;
+
 public final class InsnWrapArg extends InsnArg {
 
 	private final InsnNode wrappedInsn;
 
-	public InsnWrapArg(InsnNode insn) {
+	public InsnWrapArg(@NotNull InsnNode insn) {
 		RegisterArg result = insn.getResult();
 		this.type = result != null ? result.getType() : ArgType.VOID;
 		this.wrappedInsn = insn;
@@ -28,6 +30,34 @@ public final class InsnWrapArg extends InsnArg {
 	}
 
 	@Override
+	public int hashCode() {
+		return wrappedInsn.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof InsnWrapArg)) {
+			return false;
+		}
+		InsnWrapArg that = (InsnWrapArg) o;
+		InsnNode thisInsn = wrappedInsn;
+		InsnNode thatInsn = that.wrappedInsn;
+		if (!thisInsn.isSame(thatInsn)) {
+			return false;
+		}
+		int count = thisInsn.getArgsCount();
+		for (int i = 0; i < count; i++) {
+			if (!thisInsn.getArg(i).equals(thatInsn.getArg(i))) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	@Override
 	public String toString() {
 		return "(wrap: " + type + "\n  " + wrappedInsn + ")";
 	}

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

 package jadx.core.dex.instructions.args;
 
+import org.jetbrains.annotations.NotNull;
+
 public final class NamedArg extends InsnArg implements Named {
 
+	@NotNull
 	private String name;
 
-	public NamedArg(String name, ArgType type) {
+	public NamedArg(@NotNull String name, @NotNull ArgType type) {
 		this.name = name;
 		this.type = type;
 	}
 
+	@NotNull
 	public String getName() {
 		return name;
 	}
@@ -18,11 +22,28 @@ public final class NamedArg extends InsnArg implements Named {
 		return true;
 	}
 
-	public void setName(String name) {
+	public void setName(@NotNull String name) {
 		this.name = name;
 	}
 
 	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof NamedArg)) {
+			return false;
+		}
+		return name.equals(((NamedArg) o).name);
+
+	}
+
+	@Override
+	public int hashCode() {
+		return name.hashCode();
+	}
+
+	@Override
 	public String toString() {
 		return "(" + name + " " + type + ")";
 	}

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

@@ -55,8 +55,7 @@ public class TypeImmutableArg extends RegisterArg {
 		if (!super.equals(obj)) {
 			return false;
 		}
-		TypeImmutableArg that = (TypeImmutableArg) obj;
-		return isThis == that.isThis;
+		return isThis == ((TypeImmutableArg) obj).isThis;
 	}
 
 	@Override

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

@@ -252,6 +252,10 @@ public class SimplifyVisitor extends AbstractVisitor {
 			InsnArg reg = null;
 			if (getType == InsnType.IGET) {
 				reg = get.getArg(0);
+				InsnArg putReg = insn.getArg(1);
+				if (!reg.equals(putReg)) {
+					return null;
+				}
 			}
 			FieldArg fArg = new FieldArg(field, reg);
 			if (reg != null) {
@@ -268,7 +272,7 @@ public class SimplifyVisitor extends AbstractVisitor {
 				}
 				return new ArithNode(ArithOp.ADD, fArg, InsnArg.wrapArg(concat));
 			}
-		} catch (Throwable e) {
+		} catch (Exception e) {
 			LOG.debug("Can't convert field arith insn: {}, mth: {}", insn, mth, e);
 		}
 		return null;

jadx-core/src/test/java/jadx/tests/integration/arith/TestFieldIncrement3.java

+package jadx.tests.integration.arith;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.IntegrationTest;
+
+import java.util.Random;
+
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertThat;
+
+public class TestFieldIncrement3 extends IntegrationTest {
+
+	public static class TestCls {
+		static int tileX;
+		static int tileY;
+		static Vector2 targetPos = new Vector2();
+		static Vector2 directVect = new Vector2();
+		static Vector2 newPos = new Vector2();
+
+		private static void test() {
+			Random rd = new Random();
+			int direction = rd.nextInt(7);
+			switch (direction) {
+				case 0:
+					targetPos.x = (float) (((tileX + 1) * 55) + 55);
+					targetPos.y = (float) (((tileY + 1) * 35) + 35);
+					break;
+				case 2:
+					targetPos.x = (float) (((tileX + 1) * 55) + 55);
+					targetPos.y = (float) (((tileY - 1) * 35) + 35);
+					break;
+				case 4:
+					targetPos.x = (float) (((tileX - 1) * 55) + 55);
+					targetPos.y = (float) (((tileY - 1) * 35) + 35);
+					break;
+				case 6:
+					targetPos.x = (float) (((tileX - 1) * 55) + 55);
+					targetPos.y = (float) (((tileY + 1) * 35) + 35);
+					break;
+				default:
+					break;
+			}
+			directVect.x = targetPos.x - newPos.x;
+			directVect.y = targetPos.y - newPos.y;
+
+			float hPos = (float) Math.sqrt((double) ((directVect.x * directVect.x) + (directVect.y * directVect.y)));
+			directVect.x /= hPos;
+			directVect.y /= hPos;
+		}
+
+		static class Vector2 {
+			public float x;
+			public float y;
+
+			public Vector2() {
+				this.x = 0.0f;
+				this.y = 0.0f;
+			}
+
+			public boolean equals(Vector2 other) {
+				return (this.x == other.x && this.y == other.y);
+			}
+		}
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsString("directVect.x = targetPos.x - newPos.x;"));
+	}
+}