ART: Allow PackedSwitch instructions with zero targets

Optimizing and the interpreter wrongly assumed that a PackedSwitch
always has at least one target. This patch removes the corresponding
DCHECKs and adds a regression test case.

This is a resubmission of CL I32b7033ed38de6f1d1a6ee5d5bf12f3a47c9b37e

Bug: 21863783
Change-Id: I04e6e124bdd16591ba27c79490e6ce183c36b691
(cherry picked from commit 2ef645ba50544b879a82ea30e606f18c9af98917)

4 files changed, 64 insertions, 0 deletions

diff --git a/test/501-regression-packed-switch/expected.txt b/test/501-regression-packed-switch/expected.txt
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/test/501-regression-packed-switch/expected.txt
diff --git a/test/501-regression-packed-switch/info.txt b/test/501-regression-packed-switch/info.txt
new file mode 100644
index 0000000000..fbd93fa815
--- /dev/null
+++ b/test/501-regression-packed-switch/info.txt
@@ -0,0 +1,2 @@
+Regression test for the interpreter and optimizing's builder which used
+to trip when compiled code contained a packed switch with no targets.
diff --git a/test/501-regression-packed-switch/smali/Test.smali b/test/501-regression-packed-switch/smali/Test.smali
new file mode 100644
index 0000000000..8756ed5f23
--- /dev/null
+++ b/test/501-regression-packed-switch/smali/Test.smali
@@ -0,0 +1,29 @@
+#
+# Copyright (C) 2015 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.
+
+.class public LTest;
+
+.super Ljava/lang/Object;
+
+.method public static EmptyPackedSwitch(I)I
+  .registers 1
+  packed-switch v0, :pswitch_data_6a
+  const/4 v0, 0x5
+  return v0
+
+  :pswitch_data_6a
+  .packed-switch 0x0
+  .end packed-switch
+.end method
diff --git a/test/501-regression-packed-switch/src/Main.java b/test/501-regression-packed-switch/src/Main.java
new file mode 100644
index 0000000000..b80bc62c50
--- /dev/null
+++ b/test/501-regression-packed-switch/src/Main.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 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;
+import java.lang.reflect.Type;
+
+public class Main {
+
+  // Workaround for b/18051191.
+  class InnerClass {}
+
+  public static void main(String args[]) throws Exception {
+    Class<?> c = Class.forName("Test");
+    Method m = c.getMethod("EmptyPackedSwitch", new Class[] { int.class });
+    Integer result = (Integer) m.invoke(null, new Integer(42));
+    if (result != 5) {
+      throw new Error("Expected 5, got " + result);
+    }
+  }
+}