Fix allocation stats bug on ARM; add unit test.

runtime/vm/heap_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 
 #include "platform/assert.h"
 #include "vm/dart_api_impl.h"
 #include "vm/globals.h"
 #include "vm/heap.h"
@@ skipping 151 matching lines @@
   EXPECT_EQ(0, class_stats->post_gc.old_count);
   EXPECT_EQ(0, class_stats->recent.old_count);
   // Perform GC.
   heap->CollectGarbage(Heap::kOld);
   EXPECT_EQ(0, class_stats->pre_gc.old_count);
   EXPECT_EQ(0, class_stats->post_gc.old_count);
   EXPECT_EQ(0, class_stats->recent.old_count);
 }
 
 
+TEST_CASE(ArrayHeapStats) {
+  const char* kScriptChars =
+  "List f(int len) {\n"
+  "  return new List(len);\n"
+  "}\n"
+  ""
+  "main() {\n"
+  "  return f(1234);\n"
+  "}\n";
+  Dart_Handle h_lib = TestCase::LoadTestScript(kScriptChars, NULL);
+  Isolate* isolate = Isolate::Current();
+  ClassTable* class_table = isolate->class_table();
+  intptr_t cid = kArrayCid;
+  ClassHeapStats* class_stats =
+      ClassHeapStatsTestHelper::GetHeapStatsForCid(class_table,
+                                                   cid);
+  Dart_EnterScope();
+  // Invoke 'main' twice, since initial compilation might trigger extra array
+  // allocations.
+  Dart_Handle result = Dart_Invoke(h_lib, NewString("main"), 0, NULL);
+  EXPECT_VALID(result);
+  EXPECT(!Dart_IsNull(result));
+  Library& lib = Library::Handle();
+  lib ^= Api::UnwrapHandle(h_lib);
+  EXPECT(!lib.IsNull());
+  intptr_t before = class_stats->recent.new_size;
+  Dart_Handle result2 = Dart_Invoke(h_lib, NewString("main"), 0, NULL);
+  EXPECT_VALID(result2);
+  EXPECT(!Dart_IsNull(result2));
+  intptr_t after = class_stats->recent.new_size;
+  const intptr_t expected_size = Array::InstanceSize(1234);
+  // Invoking the method might involve some additional tiny array allocations,
+  // so we allow slightly more than expected.
+  static const intptr_t kTolerance = 10 * kWordSize;
+  EXPECT_LE(expected_size, after - before);
+  EXPECT_GT(expected_size + kTolerance, after - before);
+  Dart_ExitScope();
+}
+
+
 class FindOnly : public FindObjectVisitor {
  public:
   FindOnly(Isolate* isolate, RawObject* target)
       : FindObjectVisitor(isolate), target_(target) {
     ASSERT(isolate->no_gc_scope_depth() != 0);
   }
   virtual ~FindOnly() { }
 
   virtual bool FindObject(RawObject* obj) const {
     return obj == target_;
@@ skipping 24 matching lines @@
     }
   }
   {
     NoGCScope no_gc;
     FindNothing find_nothing;
     EXPECT(Object::null() == heap->FindObject(&find_nothing));
   }
 }
 
 }  // namespace dart.