Fix std::ostream printing for ObjectPtr-derived types

Moving the declaration of operator<< from objects-printer.cc to
heap-object.h makes sure that it is visible.

Change-Id: I316db9c03a464974129b8e9c776423bb80066cdd
Reviewed-on: https://chromium-review.googlesource.com/c/1382737Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58350}

src/objects-printer.cc

@@ -68,11 +68,6 @@ namespace internal {
 
 #ifdef OBJECT_PRINT
 
-std::ostream& operator<<(std::ostream& os, const ObjectPtr o) {
-  os << reinterpret_cast<void*>(o.ptr());
-  return os;
-}
-
 void Object::Print() {
   StdoutStream os;
   this->Print(os);

src/objects.cc

@@ -2583,7 +2583,12 @@ void Object::ShortPrint(StringStream* accumulator) {
 
 void Object::ShortPrint(std::ostream& os) { os << Brief(this); }
 
-void ObjectPtr::ShortPrint(std::ostream& os) { os << Brief(*this); }
+void ObjectPtr::ShortPrint(std::ostream& os) const { os << Brief(*this); }
+
+std::ostream& operator<<(std::ostream& os, const ObjectPtr& obj) {
+  obj.ShortPrint(os);
+  return os;
+}
 
 void MaybeObject::ShortPrint(FILE* out) {
   OFStream os(out);

src/objects/heap-object-inl.h

@@ -96,13 +96,13 @@ void ObjectPtr::VerifyApiCallResultType() {
   reinterpret_cast<Object*>(ptr())->VerifyApiCallResultType();
 }
 
-void ObjectPtr::ShortPrint(FILE* out) {
+void ObjectPtr::ShortPrint(FILE* out) const {
   return reinterpret_cast<Object*>(ptr())->ShortPrint(out);
 }
 
-void ObjectPtr::Print() { reinterpret_cast<Object*>(ptr())->Print(); }
+void ObjectPtr::Print() const { reinterpret_cast<Object*>(ptr())->Print(); }
 
-void ObjectPtr::Print(std::ostream& os) {
+void ObjectPtr::Print(std::ostream& os) const {
   reinterpret_cast<Object*>(ptr())->Print(os);
 }
 

src/objects/heap-object.h

@@ -129,10 +129,10 @@ class ObjectPtr {
 
   inline void VerifyApiCallResultType();
 
-  inline void ShortPrint(FILE* out = stdout);
-  void ShortPrint(std::ostream& os);  // NOLINT
-  inline void Print();
-  inline void Print(std::ostream& os);
+  inline void ShortPrint(FILE* out = stdout) const;
+  void ShortPrint(std::ostream& os) const;  // NOLINT
+  inline void Print() const;
+  inline void Print(std::ostream& os) const;
 
   // For use with std::unordered_set.
   struct Hasher {
@@ -154,6 +154,9 @@ bool ObjectPtr::IsHeapObject() const {
   return !IsSmi();
 }
 
+V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os,
+                                           const ObjectPtr& obj);
+
 // Replacement for HeapObject; temporarily separate for incremental transition:
 class HeapObjectPtr : public ObjectPtr {
  public: