fix: correct merge code variables across PHI instructions (#930)

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

@@ -166,6 +166,27 @@ public class SSAVar {
 		return usedInPhi;
 	}
 
+	/**
+	 * Concat assign PHI insn and usedInPhi
+	 */
+	public List<PhiInsn> getPhiList() {
+		InsnNode assignInsn = getAssign().getParentInsn();
+		if (assignInsn != null && assignInsn.getType() == InsnType.PHI) {
+			PhiInsn assignPhi = (PhiInsn) assignInsn;
+			if (usedInPhi == null) {
+				return Collections.singletonList(assignPhi);
+			}
+			List<PhiInsn> list = new ArrayList<>(1 + usedInPhi.size());
+			list.add(assignPhi);
+			list.addAll(usedInPhi);
+			return list;
+		}
+		if (usedInPhi == null) {
+			return Collections.emptyList();
+		}
+		return usedInPhi;
+	}
+
 	public boolean isUsedInPhi() {
 		return usedInPhi != null && !usedInPhi.isEmpty();
 	}

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

@@ -70,11 +70,11 @@ public class InitCodeVariables extends AbstractVisitor {
 	}
 
 	private static void setCodeVar(SSAVar ssaVar, CodeVar codeVar) {
-		List<PhiInsn> usedInPhiList = ssaVar.getUsedInPhi();
-		if (!usedInPhiList.isEmpty()) {
+		List<PhiInsn> phiList = ssaVar.getPhiList();
+		if (!phiList.isEmpty()) {
 			Set<SSAVar> vars = new LinkedHashSet<>();
 			vars.add(ssaVar);
-			collectConnectedVars(usedInPhiList, vars);
+			collectConnectedVars(phiList, vars);
 			setCodeVarType(codeVar, vars);
 			vars.forEach(var -> {
 				if (var.isCodeVarSet()) {
@@ -105,15 +105,18 @@ public class InitCodeVariables extends AbstractVisitor {
 	}
 
 	private static void collectConnectedVars(List<PhiInsn> phiInsnList, Set<SSAVar> vars) {
+		if (phiInsnList.isEmpty()) {
+			return;
+		}
 		for (PhiInsn phiInsn : phiInsnList) {
 			SSAVar resultVar = phiInsn.getResult().getSVar();
 			if (vars.add(resultVar)) {
-				collectConnectedVars(resultVar.getUsedInPhi(), vars);
+				collectConnectedVars(resultVar.getPhiList(), vars);
 			}
 			phiInsn.getArguments().forEach(arg -> {
 				SSAVar sVar = ((RegisterArg) arg).getSVar();
 				if (vars.add(sVar)) {
-					collectConnectedVars(sVar.getUsedInPhi(), vars);
+					collectConnectedVars(sVar.getPhiList(), vars);
 				}
 			});
 		}

jadx-core/src/test/java/jadx/tests/integration/variables/TestVariablesInLoop.java

+package jadx.tests.integration.variables;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.SmaliTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestVariablesInLoop extends SmaliTest {
+
+	@Test
+	public void test() {
+		assertThat(getClassNodeFromSmali())
+				.code()
+				.containsOne("int i;")
+				.countString(2, "i = 0;")
+				.doesNotContain("i3");
+	}
+}

jadx-core/src/test/smali/variables/TestVariablesInLoop.smali

+.class public abstract Lvariables/TestVariablesInLoop;
+.super Ljava/lang/Object;
+.source "SourceFile"
+
+.implements Ljava/util/List;
+
+.annotation system Ldalvik/annotation/Signature;
+    value = {
+        "Ljava/lang/Object;",
+        "Ljava/util/List<",
+        "Ljava/lang/Long;",
+        ">;"
+    }
+.end annotation
+
+.method static test(Ljava/util/List;)I
+    .locals 5
+    .annotation system Ldalvik/annotation/Signature;
+        value = {
+            "(",
+            "Ljava/util/List<",
+            "Ljava/lang/Long;",
+            ">;)I"
+        }
+    .end annotation
+
+    invoke-interface {p0}, Ljava/util/List;->size()I
+
+    move-result v0
+
+    const/4 v1, 0x0
+
+    if-nez v0, :cond_0
+
+    return v1
+
+    :cond_0
+    instance-of v2, p0, Lvariables/TestVariablesInLoop;
+
+    if-eqz v2, :cond_1
+
+    check-cast p0, Lvariables/TestVariablesInLoop;
+
+    const/4 v2, 0x0
+
+    :goto_0
+    if-ge v1, v0, :cond_2
+
+    invoke-virtual {p0, v1}, Lvariables/TestVariablesInLoop;->getLong(I)J
+
+    move-result-wide v3
+
+    invoke-static {v3, v4}, Lvariables/TestVariablesInLoop;->mth(J)I
+
+    move-result v3
+
+    add-int/2addr v2, v3
+
+    add-int/lit8 v1, v1, 0x1
+
+    goto :goto_0
+
+    :cond_1
+    const/4 v2, 0x0
+
+    :goto_1
+    if-ge v1, v0, :cond_2
+
+    invoke-interface {p0, v1}, Ljava/util/List;->get(I)Ljava/lang/Object;
+
+    move-result-object v3
+
+    check-cast v3, Ljava/lang/Long;
+
+    invoke-virtual {v3}, Ljava/lang/Long;->longValue()J
+
+    move-result-wide v3
+
+    invoke-static {v3, v4}, Lvariables/TestVariablesInLoop;->mth(J)I
+
+    move-result v3
+
+    add-int/2addr v2, v3
+
+    add-int/lit8 v1, v1, 0x1
+
+    goto :goto_1
+
+    :cond_2
+    return v2
+.end method
+
+.method public final getLong(I)J
+    .locals 2
+    const/16 v0, 0x0
+    return-wide v0
+.end method
+
+.method static mth(J)I
+    .locals 2
+    const/4 v0, 0x0
+    return v0
+.end method