Decouple root visitors from object visitors.

src/objects.h

 // Copyright 2015 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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 933 matching lines @@
 class LookupIterator;
 class FieldType;
 class Module;
 class ModuleDescriptor;
 class ModuleInfoEntry;
 class ModuleInfo;
 class ObjectHashTable;
 class ObjectVisitor;
 class PropertyCell;
 class PropertyDescriptor;
+class RootVisitor;
 class SafepointEntry;
 class SharedFunctionInfo;
 class StringStream;
 class TypeFeedbackInfo;
 class FeedbackMetadata;
 class FeedbackVector;
 class WeakCell;
 class TransitionArray;
 class TemplateList;
 
@@ skipping 7738 matching lines @@
 };
 
 
 // Utility superclass for stack-allocated objects that must be updated
 // on gc.  It provides two ways for the gc to update instances, either
 // iterating or updating after gc.
 class Relocatable BASE_EMBEDDED {
  public:
   explicit inline Relocatable(Isolate* isolate);
   inline virtual ~Relocatable();
-  virtual void IterateInstance(ObjectVisitor* v) { }
+  virtual void IterateInstance(RootVisitor* v) {}
   virtual void PostGarbageCollection() { }
 
   static void PostGarbageCollectionProcessing(Isolate* isolate);
   static int ArchiveSpacePerThread();
   static char* ArchiveState(Isolate* isolate, char* to);
   static char* RestoreState(Isolate* isolate, char* from);
-  static void Iterate(Isolate* isolate, ObjectVisitor* v);
-  static void Iterate(ObjectVisitor* v, Relocatable* top);
-  static char* Iterate(ObjectVisitor* v, char* t);
+  static void Iterate(Isolate* isolate, RootVisitor* v);
+  static void Iterate(RootVisitor* v, Relocatable* top);
+  static char* Iterate(RootVisitor* v, char* t);
 
  private:
   Isolate* isolate_;
   Relocatable* prev_;
 };
 
 
 // A flat string reader provides random access to the contents of a
 // string independent of the character width of the string.  The handle
 // must be valid as long as the reader is being used.
@@ skipping 1402 matching lines @@
 
  private:
   // Bit position in the flag, from least significant bit position.
   static const int kIsEvalBit = 0;
   static const int kIsConstructorBit = 1;
   static const int kIsWasmBit = 2;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(StackFrameInfo);
 };
 
-#define VISITOR_SYNCHRONIZATION_TAGS_LIST(V)                               \
-  V(kStringTable, "string_table", "(Internalized strings)")                \
-  V(kExternalStringsTable, "external_strings_table", "(External strings)") \
-  V(kStrongRootList, "strong_root_list", "(Strong roots)")                 \
-  V(kSmiRootList, "smi_root_list", "(Smi roots)")                          \
-  V(kBootstrapper, "bootstrapper", "(Bootstrapper)")                       \
-  V(kTop, "top", "(Isolate)")                                              \
-  V(kRelocatable, "relocatable", "(Relocatable)")                          \
-  V(kDebug, "debug", "(Debugger)")                                         \
-  V(kCompilationCache, "compilationcache", "(Compilation cache)")          \
-  V(kHandleScope, "handlescope", "(Handle scope)")                         \
-  V(kDispatchTable, "dispatchtable", "(Dispatch table)")                   \
-  V(kBuiltins, "builtins", "(Builtins)")                                   \
-  V(kGlobalHandles, "globalhandles", "(Global handles)")                   \
-  V(kEternalHandles, "eternalhandles", "(Eternal handles)")                \
-  V(kThreadManager, "threadmanager", "(Thread manager)")                   \
-  V(kStrongRoots, "strong roots", "(Strong roots)")                        \
-  V(kExtensions, "Extensions", "(Extensions)")
-
-class VisitorSynchronization : public AllStatic {
- public:
-#define DECLARE_ENUM(enum_item, ignore1, ignore2) enum_item,
-  enum SyncTag {
-    VISITOR_SYNCHRONIZATION_TAGS_LIST(DECLARE_ENUM)
-    kNumberOfSyncTags
-  };
-#undef DECLARE_ENUM
-
-  static const char* const kTags[kNumberOfSyncTags];
-  static const char* const kTagNames[kNumberOfSyncTags];
-};
-
 // Abstract base class for visiting, and optionally modifying, the
 // pointers contained in Objects. Used in GC and serialization/deserialization.
+// TODO(ulan): move to src/visitors.h
 class ObjectVisitor BASE_EMBEDDED {
  public:
   virtual ~ObjectVisitor() {}
 
   // Visits a contiguous arrays of pointers in the half-open range
   // [start, end). Any or all of the values may be modified on return.
   virtual void VisitPointers(Object** start, Object** end) = 0;
 
   // Handy shorthand for visiting a single pointer.
   virtual void VisitPointer(Object** p) { VisitPointers(p, p + 1); }
@@ skipping 27 matching lines @@
   virtual void VisitEmbeddedPointer(RelocInfo* rinfo);
 
   // Visits an external reference embedded into a code object.
   virtual void VisitExternalReference(RelocInfo* rinfo);
 
   // Visits an external reference.
   virtual void VisitExternalReference(Address* p) {}
 
   // Visits an (encoded) internal reference.
   virtual void VisitInternalReference(RelocInfo* rinfo) {}
-
-  // Intended for serialization/deserialization checking: insert, or
-  // check for the presence of, a tag at this position in the stream.
-  // Also used for marking up GC roots in heap snapshots.
-  virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
 };
 
 
 // BooleanBit is a helper class for setting and getting a bit in an integer.
 class BooleanBit : public AllStatic {
  public:
   static inline bool get(int value, int bit_position) {
     return (value & (1 << bit_position)) != 0;
   }
 
   static inline int set(int value, int bit_position, bool v) {
     if (v) {
       value |= (1 << bit_position);
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_H_