ART: Special form of lock aliasing

Check whether the instruction immediately before a monitor-enter
is a move-object, establishing previously untracked lock aliasing
in a low-overhead manner.

Bug: 20102779
Bug: 21169615
Bug: 21988678
Bug: 23300986
Change-Id: Ia10d6219357e7bce29f58134637b07d3f4857b2f
diff --git a/test/800-smali/expected.txt b/test/800-smali/expected.txt
index 21a8171..6a452eb 100644
--- a/test/800-smali/expected.txt
+++ b/test/800-smali/expected.txt
@@ -1,6 +1,5 @@
 PackedSwitch
 b/17790197
-b/17978759
 FloatBadArgReg
 negLong
 sameFieldNames
@@ -42,4 +41,5 @@
 b/23201502 (float)
 b/23201502 (double)
 b/23300986
+b/23300986 (2)
 Done!
diff --git a/test/800-smali/smali/b_17978759.smali b/test/800-smali/smali/b_17978759.smali
deleted file mode 100644
index 07bcae5..0000000
--- a/test/800-smali/smali/b_17978759.smali
+++ /dev/null
@@ -1,28 +0,0 @@
-.class public LB17978759;
-.super Ljava/lang/Object;
-
-  .method public constructor <init>()V
-    .registers 1
-    invoke-direct {p0}, Ljava/lang/Object;-><init>()V
-    return-void
-  .end method
-
-  .method public test()V
-    .registers 2
-
-    move-object   v0, p0
-    # v0 and p0 alias
-    monitor-enter p0
-    # monitor-enter on p0
-    monitor-exit  v0
-    # monitor-exit on v0, however, verifier doesn't track this and so this is
-    # a warning. Verifier will still think p0 is locked.
-
-    move-object   v0, p0
-    # v0 will now appear locked.
-    monitor-enter v0
-    # Attempt to lock v0 twice is a verifier failure.
-    monitor-exit  v0
-
-    return-void
-  .end method
diff --git a/test/800-smali/smali/b_23300986.smali b/test/800-smali/smali/b_23300986.smali
index 5ed8e5e..f008b92 100644
--- a/test/800-smali/smali/b_23300986.smali
+++ b/test/800-smali/smali/b_23300986.smali
@@ -11,3 +11,13 @@
    monitor-exit v1
    return-void
 .end method
+
+.method public static runAliasBeforeEnter(Ljava/lang/Object;)V
+   .registers 3
+   move-object v1, v2      # Copy parameter into v1, establishing an alias.
+   monitor-enter v2        # Lock on parameter
+   monitor-exit v1         # Unlock on alias
+   monitor-enter v2        # Do it again.
+   monitor-exit v1
+   return-void
+.end method
diff --git a/test/800-smali/src/Main.java b/test/800-smali/src/Main.java
index a89b849..183958a 100644
--- a/test/800-smali/src/Main.java
+++ b/test/800-smali/src/Main.java
@@ -53,8 +53,6 @@
                 new Object[]{123}, null, 123));
 
         testCases.add(new TestCase("b/17790197", "B17790197", "getInt", null, null, 100));
-        testCases.add(new TestCase("b/17978759", "B17978759", "test", null, new VerifyError(),
-                null));
         testCases.add(new TestCase("FloatBadArgReg", "FloatBadArgReg", "getInt",
                 new Object[]{100}, null, 100));
         testCases.add(new TestCase("negLong", "negLong", "negLong", null, null, 122142L));
@@ -129,6 +127,8 @@
                 new NullPointerException(), null));
         testCases.add(new TestCase("b/23300986", "B23300986", "runAliasAfterEnter",
                 new Object[] { new Object() }, null, null));
+        testCases.add(new TestCase("b/23300986 (2)", "B23300986", "runAliasBeforeEnter",
+                new Object[] { new Object() }, null, null));
     }
 
     public void runTests() {