[in-place weak refs] Add MaybeObject::Print.

BUG=v8:7308

Change-Id: I12a38a6099f0ffd8718dc5cb77433baa75bc0411
Reviewed-on: https://chromium-review.googlesource.com/1059110
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53183}

src/objects-printer.cc

@@ -1999,6 +1999,29 @@ void InterpreterData::InterpreterDataPrint(std::ostream& os) {  // NOLINT
   os << "\n";
 }
 
+void MaybeObject::Print() {
+  OFStream os(stdout);
+  this->Print(os);
+  os << std::flush;
+}
+
+void MaybeObject::Print(std::ostream& os) {
+  Smi* smi;
+  HeapObject* heap_object;
+  if (ToSmi(&smi)) {
+    smi->SmiPrint(os);
+  } else if (IsClearedWeakHeapObject()) {
+    os << "[cleared]";
+  } else if (ToWeakHeapObject(&heap_object)) {
+    os << "[weak] ";
+    heap_object->HeapObjectPrint(os);
+  } else if (ToStrongHeapObject(&heap_object)) {
+    heap_object->HeapObjectPrint(os);
+  } else {
+    UNREACHABLE();
+  }
+}
+
 #endif  // OBJECT_PRINT
 
 // TODO(cbruni): remove once the new maptracer is in place.
@@ -2228,6 +2251,7 @@ void JSObject::PrintTransitions(std::ostream& os) {  // NOLINT
   os << "\n - transitions";
   ta.PrintTransitions(os);
 }
+
 #endif  // defined(DEBUG) || defined(OBJECT_PRINT)
 }  // namespace internal
 }  // namespace v8

src/objects.cc

@@ -2448,6 +2448,18 @@ void Object::ShortPrint(StringStream* accumulator) {
 
 void Object::ShortPrint(std::ostream& os) { os << Brief(this); }
 
+void MaybeObject::ShortPrint(FILE* out) {
+  OFStream os(out);
+  os << MaybeObjectBrief(this);
+}
+
+void MaybeObject::ShortPrint(StringStream* accumulator) {
+  std::ostringstream os;
+  os << MaybeObjectBrief(this);
+  accumulator->Add(os.str().c_str());
+}
+
+void MaybeObject::ShortPrint(std::ostream& os) { os << MaybeObjectBrief(this); }
 
 std::ostream& operator<<(std::ostream& os, const Brief& v) {
   if (v.value->IsSmi()) {

src/objects/maybe-object.h

@@ -61,6 +61,23 @@ class MaybeObject {
   static void VerifyMaybeObjectPointer(MaybeObject* p);
 #endif
 
+  // Prints this object without details.
+  void ShortPrint(FILE* out = stdout);
+
+  // Prints this object without details to a message accumulator.
+  void ShortPrint(StringStream* accumulator);
+
+  void ShortPrint(std::ostream& os);
+
+#ifdef OBJECT_PRINT
+  void Print();
+
+  void Print(std::ostream& os);
+#else
+  void Print() { ShortPrint(); }
+  void Print(std::ostream& os) { ShortPrint(os); }
+#endif
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(MaybeObject);
 };