Start moving stack-related stuff out of thread.h.

This was in preparation for implementing "SmartFrame", which is back on hold
while I finish finalization.

Change-Id: I006c9cfbc34520b9b0a72972611036d908a1d84b
diff --git a/src/stack.h b/src/stack.h
new file mode 100644
index 0000000..ae413d2
--- /dev/null
+++ b/src/stack.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+#ifndef ART_SRC_STACK_H_
+#define ART_SRC_STACK_H_
+
+#include "macros.h"
+
+#include <stdint.h>
+
+namespace art {
+
+class Method;
+class Thread;
+
+struct NativeToManagedRecord {
+  NativeToManagedRecord* link_;
+  void* last_top_of_managed_stack_;
+  uintptr_t last_top_of_managed_stack_pc_;
+};
+
+// Iterator over managed frames up to the first native-to-managed transition.
+class PACKED Frame {
+ public:
+  Frame() : sp_(NULL) {}
+
+  Method* GetMethod() const {
+    return (sp_ != NULL) ? *sp_ : NULL;
+  }
+
+  bool HasNext() const {
+    return NextMethod() != NULL;
+  }
+
+  void Next();
+
+  uintptr_t GetReturnPC() const;
+
+  uintptr_t LoadCalleeSave(int num) const;
+
+  uintptr_t GetVReg(Method* method, int vreg) const;
+
+  Method** GetSP() const {
+    return sp_;
+  }
+
+  // TODO: this is here for testing, remove when we have exception unit tests
+  // that use the real stack
+  void SetSP(Method** sp) {
+    sp_ = sp;
+  }
+
+  // Is this a frame for a real method (native or with dex code)
+  bool HasMethod() const;
+
+ private:
+  Method* NextMethod() const;
+
+  friend class Thread;
+
+  Method** sp_;
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_STACK_H_