Fix region space when used with SetLengthToUsableSizeVisitor.

The region space relies on obj->SizeOf for some of its logic.
By having SetLengthToUsableSizeVisitor "change" the SizeOf
what's being allocated.

The bug happens during RegionSpace::ClearFromSpace: for unevac regions
we iterate over following regions. If LiveBytes != Top() - Begin()
(which happen for large allocations using SetLengthToUsableSizeVisitor),
we break the loop.

The next region to analyze is a large tail, and we see LiveBytes() == 0
(tails apparently always have live bytes == 0), the code is then
happy to release the large tail, even though the large object is still
live.

bug: 37187694
bug: 62889232
Test: 659-unpadded-array
Change-Id: Ia99b67256b0e28a80095bd5cdae9068ea5e8b4a8

1 files changed, 52 insertions, 0 deletions

diff --git a/test/659-unpadded-array/src-art/Main.java b/test/659-unpadded-array/src-art/Main.java
new file mode 100644
index 0000000000..80fd6e2f6f
--- /dev/null
+++ b/test/659-unpadded-array/src-art/Main.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2017 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 dalvik.system.VMRuntime;
+
+public class Main {
+  public static void main(String[] args) {
+    // Call our optimization API, we used to have a bug in the RegionSpace on large
+    // objects allocated through it.
+    Object[] o = (Object[]) VMRuntime.getRuntime().newUnpaddedArray(Object.class, 70000);
+
+    // Make the test run for 30 seconds to be less dependent on GC heuristics.
+    long time = System.currentTimeMillis();
+    int i = 1;
+    do {
+      allocateIntArray(i);
+      for (int j = 0; j < o.length; j++) {
+        if (o[j] != null) {
+          // Just print, not throw, to get into "interesting" issues (eg the first
+          // element that will not be null is the class of the object, the second is
+          // actually the first element of the int array).
+          System.out.println("Unexpected value: " + o[j]);
+        }
+      }
+      if (i < 100000) {
+        i++;
+      } else {
+        i = 0;
+      }
+    } while (System.currentTimeMillis() - time < 30000);
+  }
+
+  static void allocateIntArray(int i) {
+    int[] intArray = new int[i];
+    for (int j = 0; j < intArray.length; j++) {
+      intArray[j] = 1;
+    }
+  }
+}