Add Handle/HandleScope and delete SirtRef.

Delete SirtRef and replaced it with Handle. Handles are value types
which wrap around StackReference*.

Renamed StackIndirectReferenceTable to HandleScope.

Added a scoped handle wrapper which wraps around an Object** and
restores it in its destructor.

Renamed Handle::get -> Get.

Bug: 8473721

Change-Id: Idbfebd4f35af629f0f43931b7c5184b334822c7a

1 files changed, 74 insertions, 0 deletions

diff --git a/runtime/handle_scope_test.cc b/runtime/handle_scope_test.cc
new file mode 100644
index 0000000..de563c1
--- /dev/null
+++ b/runtime/handle_scope_test.cc
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+#include "gtest/gtest.h"
+#include "handle_scope-inl.h"
+#include "scoped_thread_state_change.h"
+#include "thread.h"
+
+namespace art {
+
+// Handle scope with a fixed size which is allocated on the stack.
+template<size_t kNumReferences>
+class NoThreadStackHandleScope : public HandleScope {
+ public:
+  explicit NoThreadStackHandleScope() : HandleScope(kNumReferences) {
+  }
+  ~NoThreadStackHandleScope() {
+  }
+
+ private:
+  // references_storage_ needs to be first so that it matches the address of references_
+  StackReference<mirror::Object> references_storage_[kNumReferences];
+};
+
+// Test the offsets computed for members of HandleScope. Because of cross-compiling
+// it is impossible the use OFFSETOF_MEMBER, so we do some reasonable computations ourselves. This
+// test checks whether we do the right thing.
+TEST(HandleScopeTest, Offsets) NO_THREAD_SAFETY_ANALYSIS {
+  // As the members of HandleScope are private, we cannot use OFFSETOF_MEMBER
+  // here. So do the inverse: set some data, and access it through pointers created from the offsets.
+  NoThreadStackHandleScope<1> test_table;
+  test_table.SetReference(0, reinterpret_cast<mirror::Object*>(0x1234));
+  test_table.SetLink(reinterpret_cast<HandleScope*>(0x5678));
+  test_table.SetNumberOfReferences(0x9ABC);
+
+  byte* table_base_ptr = reinterpret_cast<byte*>(&test_table);
+
+  {
+    uintptr_t* link_ptr = reinterpret_cast<uintptr_t*>(table_base_ptr +
+        HandleScope::LinkOffset(kPointerSize));
+    EXPECT_EQ(*link_ptr, static_cast<size_t>(0x5678));
+  }
+
+  {
+    uint32_t* num_ptr = reinterpret_cast<uint32_t*>(table_base_ptr +
+        HandleScope::NumberOfReferencesOffset(kPointerSize));
+    EXPECT_EQ(*num_ptr, static_cast<size_t>(0x9ABC));
+  }
+
+  {
+    // Assume sizeof(StackReference<mirror::Object>) == sizeof(uint32_t)
+    // TODO: How can we make this assumption-less but still access directly and fully?
+    EXPECT_EQ(sizeof(StackReference<mirror::Object>), sizeof(uint32_t));
+
+    uint32_t* ref_ptr = reinterpret_cast<uint32_t*>(table_base_ptr +
+        HandleScope::ReferencesOffset(kPointerSize));
+    EXPECT_EQ(*ref_ptr, static_cast<uint32_t>(0x1234));
+  }
+}
+
+}  // namespace art