[wasm] Implement frame inspection for interpreted frames

src/wasm/managed.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_WASM_MANAGED_H_
 #define V8_WASM_MANAGED_H_
 
 #include "src/factory.h"
 #include "src/global-handles.h"
 #include "src/handles.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 // An object that wraps a pointer to a C++ object and optionally deletes it
 // when the managed wrapper object is garbage collected.
 template <class CppType>
 class Managed : public Foreign {
  public:
   V8_INLINE CppType* get() {
     return reinterpret_cast<CppType*>(foreign_address());
   }
 
+  static Managed<CppType>* cast(Object* obj) {
+    SLOW_DCHECK(obj->IsForeign());
+    return reinterpret_cast<Managed<CppType>*>(obj);
+  }
+
   static Handle<Managed<CppType>> New(Isolate* isolate, CppType* ptr,
                                       bool delete_on_gc = true) {
-    Handle<Foreign> foreign =
-        isolate->factory()->NewForeign(reinterpret_cast<Address>(ptr));
-    Handle<Managed<CppType>> handle(
-        reinterpret_cast<Managed<CppType>*>(*foreign), isolate);
+    Handle<Managed<CppType>> handle = Handle<Managed<CppType>>::cast(
+        isolate->factory()->NewForeign(reinterpret_cast<Address>(ptr)));
     if (delete_on_gc) {
       RegisterWeakCallbackForDelete(isolate, handle);
     }
     return handle;
   }
 
  private:
   static void RegisterWeakCallbackForDelete(Isolate* isolate,
                                             Handle<Managed<CppType>> handle) {
     Handle<Object> global_handle = isolate->global_handles()->Create(*handle);
     GlobalHandles::MakeWeak(global_handle.location(), global_handle.location(),
                             &Managed<CppType>::Delete,
                             v8::WeakCallbackType::kFinalizer);
   }
   static void Delete(const v8::WeakCallbackInfo<void>& data) {
     Managed<CppType>** p =
         reinterpret_cast<Managed<CppType>**>(data.GetParameter());
     delete (*p)->get();
     (*p)->set_foreign_address(0);
     GlobalHandles::Destroy(reinterpret_cast<Object**>(p));
   }
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MANAGED_H_