Fix StringBuilder append assumptions.

Do not rely on use ordering, it can be different because of
SimplifyReturnThis(); just use HBackwardInstructionIterator.
Instead of checking that we find a StringBuilder.toString(),
check that it is the invoke we're trying to simplify.

Add regression test 699-checker-string-append2.

Test: testrunner.py --host --jvm -t 699-checker-string-append2
Bug: 19575890
Bug: 146014745
Change-Id: I7b16f376c16ba5a4107e9718e0acf17d82280f54

1 files changed, 40 insertions, 0 deletions

diff --git a/test/699-checker-string-append2/src/Main.java b/test/699-checker-string-append2/src/Main.java
new file mode 100644
index 0000000000..3753af603b
--- /dev/null
+++ b/test/699-checker-string-append2/src/Main.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Method;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        Class<?> c = Class.forName("B146014745");
+        Method m1 = c.getDeclaredMethod("$noinline$testAppend1", String.class, int.class);
+        String b146014745_result1 = (String) m1.invoke(null, "x", 42);
+        assertEquals("x42x42", b146014745_result1);
+        Method m2 = c.getDeclaredMethod("$noinline$testAppend2", String.class, int.class);
+        String b146014745_result2 = (String) m2.invoke(null, "x", 42);
+        assertEquals("x42x42", b146014745_result2);
+        Method m3 = c.getDeclaredMethod("$noinline$testAppend3", String.class, int.class);
+        String b146014745_result3 = (String) m3.invoke(null, "x", 42);
+        assertEquals("x42x42", b146014745_result3);
+
+        System.out.println("passed");
+    }
+
+    public static void assertEquals(String expected, String actual) {
+        if (!expected.equals(actual)) {
+            throw new AssertionError("Expected: " + expected + ", actual: " + actual);
+        }
+    }
+}