core: replace 'move' instruction instead argument inline

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

@@ -77,7 +77,7 @@ public abstract class InsnArg extends Typed {
 		return parentInsn;
 	}
 
-	public void setParentInsn(InsnNode parentInsn) {
+	public void setParentInsn(@Nullable InsnNode parentInsn) {
 		this.parentInsn = parentInsn;
 	}
 
@@ -88,7 +88,6 @@ public abstract class InsnArg extends Typed {
 		}
 		if (parent == insn) {
 			LOG.debug("Can't wrap instruction info itself: {}", insn);
-			Thread.dumpStack();
 			return null;
 		}
 		int i = getArgIndex(parent, this);

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

@@ -23,6 +23,8 @@ import java.util.List;
 import java.util.ListIterator;
 import java.util.Set;
 
+import org.jetbrains.annotations.Nullable;
+
 public class CodeShrinker extends AbstractVisitor {
 
 	@Override
@@ -227,15 +229,16 @@ public class CodeShrinker extends AbstractVisitor {
 					if (assignBlock != null
 							&& assignInsn != arg.getParentInsn()
 							&& canMoveBetweenBlocks(assignInsn, assignBlock, block, argsInfo.getInsn())) {
-						arg.wrapInstruction(assignInsn);
-						InsnList.remove(assignBlock, assignInsn);
+						if (inline(arg, assignInsn, assignBlock, mth)) {
+							InsnList.remove(assignBlock, assignInsn);
+						}
 					}
 				}
 			}
 		}
 		if (!wrapList.isEmpty()) {
 			for (WrapInfo wrapInfo : wrapList) {
-				wrapInfo.getArg().wrapInstruction(wrapInfo.getInsn());
+				inline(wrapInfo.getArg(), wrapInfo.getInsn(), block, mth);
 			}
 			for (WrapInfo wrapInfo : wrapList) {
 				insnList.remove(wrapInfo.getInsn());
@@ -243,6 +246,29 @@ public class CodeShrinker extends AbstractVisitor {
 		}
 	}
 
+	private static boolean inline(RegisterArg arg, InsnNode insn, @Nullable BlockNode block, MethodNode mth) {
+		InsnNode parentInsn = arg.getParentInsn();
+		// replace move instruction if needed
+		if (parentInsn != null && parentInsn.getType() == InsnType.MOVE) {
+			if (block == null) {
+				block = BlockUtils.getBlockByInsn(mth, parentInsn);
+			}
+			if (block != null) {
+				int index = InsnList.getIndex(block.getInstructions(), parentInsn);
+				if (index != -1) {
+					insn.setResult(parentInsn.getResult());
+					insn.copyAttributesFrom(parentInsn);
+					insn.setOffset(parentInsn.getOffset());
+
+					block.getInstructions().set(index, insn);
+					return true;
+				}
+			}
+		}
+		// simple case
+		return arg.wrapInstruction(insn) != null;
+	}
+
 	private static boolean canMoveBetweenBlocks(InsnNode assignInsn, BlockNode assignBlock,
 			BlockNode useBlock, InsnNode useInsn) {
 		if (!BlockUtils.isPathExists(assignBlock, useBlock)) {
@@ -300,7 +326,7 @@ public class CodeShrinker extends AbstractVisitor {
 			for (RegisterArg rarg : list) {
 				InsnNode ai = rarg.getAssignInsn();
 				if (ai != assignInsn && ai != null && ai != rarg.getParentInsn()) {
-					rarg.wrapInstruction(ai);
+					inline(rarg, ai, null, mth);
 				}
 			}
 			// remove method args

jadx-core/src/test/java/jadx/tests/smali/TestInlineVarArg.java

@@ -0,0 +1,21 @@
+package jadx.tests.smali;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.SmaliTest;
+
+import org.junit.Test;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.junit.Assert.assertThat;
+
+public class TestInlineVarArg extends SmaliTest {
+
+	@Test
+	public void test() {
+		noDebugInfo();
+		ClassNode cls = getClassNodeFromSmali("TestInlineVarArg");
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsOne("f(\"a\", \"b\", \"c\");"));
+	}
+}

jadx-core/src/test/smali/TestInlineVarArg.smali

@@ -0,0 +1,41 @@
+.class public LTestInlineVarArg;
+.super Ljava/lang/Object;
+
+.method public static varargs f([Ljava/lang/String;)V
+    .registers 1
+    return-void
+.end method
+
+.method public test()V
+    .registers 5
+
+    const/4 v2, 0x3
+
+    new-array v1, v2, [Ljava/lang/String;
+
+    move-object v0, v1
+
+    const/4 v2, 0x0
+
+    const-string v3, "a"
+
+    aput-object v3, v0, v2
+
+    const/4 v2, 0x1
+
+    const-string v3, "b"
+
+    aput-object v3, v0, v2
+
+    const/4 v2, 0x2
+
+    const-string v3, "c"
+
+    aput-object v3, v0, v2
+
+    move-object v1, v0
+
+    invoke-static {v1}, LTestInlineVarArg;->f([Ljava/lang/String;)V
+
+    return-void
+.end method