Merge ObjectIterator::has_next and ObjectIterator::next methods.

This reduces chances of improper usage, see http://code.google.com/p/v8/issues/detail?id=586
for more details.

BUG=586

Review URL: http://codereview.chromium.org/555072

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3696 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/debug.cc

@@ -1695,9 +1695,7 @@ void Debug::CreateScriptCache() {
   // Scan heap for Script objects.
   int count = 0;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    ASSERT(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (obj->IsScript() && Script::cast(obj)->HasValidSource()) {
       script_cache_->Add(Handle<Script>(Script::cast(obj)));
       count++;

src/heap-profiler.cc

@@ -625,8 +625,7 @@ void HeapProfiler::WriteSample() {
   ConstructorHeapProfile js_cons_profile;
   RetainerHeapProfile js_retainer_profile;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     CollectStats(obj, info);
     js_cons_profile.CollectStats(obj);
     js_retainer_profile.CollectStats(obj);

src/heap.cc

@@ -327,7 +327,7 @@ void Heap::GarbageCollectionPrologue() {
 int Heap::SizeOfObjects() {
   int total = 0;
   AllSpaces spaces;
-  while (Space* space = spaces.next()) {
+  for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
     total += space->Size();
   }
   return total;
@@ -732,13 +732,14 @@ static void VerifyNonPointerSpacePointers() {
   // do not expect them.
   VerifyNonPointerSpacePointersVisitor v;
   HeapObjectIterator code_it(Heap::code_space());
-  while (code_it.has_next()) {
-    HeapObject* object = code_it.next();
+  for (HeapObject* object = code_it.next();
+       object != NULL; object = code_it.next())
     object->Iterate(&v);
-  }
 
   HeapObjectIterator data_it(Heap::old_data_space());
-  while (data_it.has_next()) data_it.next()->Iterate(&v);
+  for (HeapObject* object = data_it.next();
+       object != NULL; object = data_it.next())
+    object->Iterate(&v);
 }
 #endif
 
@@ -804,8 +805,8 @@ void Heap::Scavenge() {
 
   // Copy objects reachable from cells by scavenging cell values directly.
   HeapObjectIterator cell_iterator(cell_space_);
-  while (cell_iterator.has_next()) {
-    HeapObject* cell = cell_iterator.next();
+  for (HeapObject* cell = cell_iterator.next();
+       cell != NULL; cell = cell_iterator.next()) {
     if (cell->IsJSGlobalPropertyCell()) {
       Address value_address =
           reinterpret_cast<Address>(cell) +
@@ -1013,13 +1014,15 @@ void Heap::RebuildRSets() {
 
 void Heap::RebuildRSets(PagedSpace* space) {
   HeapObjectIterator it(space);
-  while (it.has_next()) Heap::UpdateRSet(it.next());
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+    Heap::UpdateRSet(obj);
 }
 
 
 void Heap::RebuildRSets(LargeObjectSpace* space) {
   LargeObjectIterator it(space);
-  while (it.has_next()) Heap::UpdateRSet(it.next());
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+    Heap::UpdateRSet(obj);
 }
 
 
@@ -3106,7 +3109,8 @@ void Heap::Print() {
   if (!HasBeenSetup()) return;
   Top::PrintStack();
   AllSpaces spaces;
-  while (Space* space = spaces.next()) space->Print();
+  for (Space* space = spaces.next(); space != NULL; space = spaces.next())
+    space->Print();
 }
 
 
@@ -3648,7 +3652,8 @@ void Heap::TearDown() {
 void Heap::Shrink() {
   // Try to shrink all paged spaces.
   PagedSpaces spaces;
-  while (PagedSpace* space = spaces.next()) space->Shrink();
+  for (PagedSpace* space = spaces.next(); space != NULL; space = spaces.next())
+    space->Shrink();
 }
 
 
@@ -3657,7 +3662,8 @@ void Heap::Shrink() {
 void Heap::Protect() {
   if (HasBeenSetup()) {
     AllSpaces spaces;
-    while (Space* space = spaces.next()) space->Protect();
+    for (Space* space = spaces.next(); space != NULL; space = spaces.next())
+      space->Protect();
   }
 }
 
@@ -3665,7 +3671,8 @@ void Heap::Protect() {
 void Heap::Unprotect() {
   if (HasBeenSetup()) {
     AllSpaces spaces;
-    while (Space* space = spaces.next()) space->Unprotect();
+    for (Space* space = spaces.next(); space != NULL; space = spaces.next())
+      space->Unprotect();
   }
 }
 
@@ -3837,34 +3844,25 @@ void HeapIterator::Shutdown() {
 }
 
 
-bool HeapIterator::has_next() {
+HeapObject* HeapIterator::next() {
   // No iterator means we are done.
-  if (object_iterator_ == NULL) return false;
+  if (object_iterator_ == NULL) return NULL;
 
-  if (object_iterator_->has_next_object()) {
+  if (HeapObject* obj = object_iterator_->next_object()) {
     // If the current iterator has more objects we are fine.
-    return true;
+    return obj;
   } else {
     // Go though the spaces looking for one that has objects.
     while (space_iterator_->has_next()) {
       object_iterator_ = space_iterator_->next();
-      if (object_iterator_->has_next_object()) {
-        return true;
+      if (HeapObject* obj = object_iterator_->next_object()) {
+        return obj;
       }
     }
   }
   // Done with the last space.
   object_iterator_ = NULL;
-  return false;
-}
-
-
-HeapObject* HeapIterator::next() {
-  if (has_next()) {
-    return object_iterator_->next_object();
-  } else {
-    return NULL;
-  }
+  return NULL;
 }
 
 

src/heap.h

@@ -1290,7 +1290,6 @@ class HeapIterator BASE_EMBEDDED {
   explicit HeapIterator();
   virtual ~HeapIterator();
 
-  bool has_next();
   HeapObject* next();
   void reset();
 

src/log.cc

@@ -1237,9 +1237,7 @@ static int EnumerateCompiledFunctions(Handle<SharedFunctionInfo>* sfis) {
   AssertNoAllocation no_alloc;
   int compiled_funcs_count = 0;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    ASSERT(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (!obj->IsSharedFunctionInfo()) continue;
     SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
     if (sfi->is_compiled()
@@ -1352,9 +1350,7 @@ void Logger::LogCompiledFunctions() {
 void Logger::LogFunctionObjects() {
   AssertNoAllocation no_alloc;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    ASSERT(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (!obj->IsJSFunction()) continue;
     JSFunction* jsf = JSFunction::cast(obj);
     if (!jsf->is_compiled()) continue;
@@ -1366,9 +1362,7 @@ void Logger::LogFunctionObjects() {
 void Logger::LogAccessorCallbacks() {
   AssertNoAllocation no_alloc;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    ASSERT(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (!obj->IsAccessorInfo()) continue;
     AccessorInfo* ai = AccessorInfo::cast(obj);
     if (!ai->name()->IsString()) continue;

src/mark-compact.cc

@@ -129,7 +129,8 @@ void MarkCompactCollector::Prepare(GCTracer* tracer) {
 #endif
 
   PagedSpaces spaces;
-  while (PagedSpace* space = spaces.next()) {
+  for (PagedSpace* space = spaces.next();
+       space != NULL; space = spaces.next()) {
     space->PrepareForMarkCompact(compacting_collection_);
   }
 
@@ -172,7 +173,7 @@ void MarkCompactCollector::Finish() {
   int old_gen_used = 0;
 
   OldSpaces spaces;
-  while (OldSpace* space = spaces.next()) {
+  for (OldSpace* space = spaces.next(); space != NULL; space = spaces.next()) {
     old_gen_recoverable += space->Waste() + space->AvailableFree();
     old_gen_used += space->Size();
   }
@@ -475,8 +476,8 @@ void MarkCompactCollector::MarkDescriptorArray(
 
 void MarkCompactCollector::CreateBackPointers() {
   HeapObjectIterator iterator(Heap::map_space());
-  while (iterator.has_next()) {
-    Object* next_object = iterator.next();
+  for (HeapObject* next_object = iterator.next();
+       next_object != NULL; next_object = iterator.next()) {
     if (next_object->IsMap()) {  // Could also be ByteArray on free list.
       Map* map = Map::cast(next_object);
       if (map->instance_type() >= FIRST_JS_OBJECT_TYPE &&
@@ -509,8 +510,7 @@ static void ScanOverflowedObjects(T* it) {
   // so that we don't waste effort pointlessly scanning for objects.
   ASSERT(!marking_stack.is_full());
 
-  while (it->has_next()) {
-    HeapObject* object = it->next();
+  for (HeapObject* object = it->next(); object != NULL; object = it->next()) {
     if (object->IsOverflowed()) {
       object->ClearOverflow();
       ASSERT(object->IsMarked());
@@ -793,8 +793,9 @@ void MarkCompactCollector::ClearNonLiveTransitions() {
   // scan the descriptor arrays of those maps, not all maps.
   // All of these actions are carried out only on maps of JSObjects
   // and related subtypes.
-  while (map_iterator.has_next()) {
-    Map* map = reinterpret_cast<Map*>(map_iterator.next());
+  for (HeapObject* obj = map_iterator.next();
+       obj != NULL; obj = map_iterator.next()) {
+    Map* map = reinterpret_cast<Map*>(obj);
     if (!map->IsMarked() && map->IsByteArray()) continue;
 
     ASSERT(SafeIsMap(map));
@@ -1282,8 +1283,7 @@ class MapCompact {
     MapIterator it;
     HeapObject* o = it.next();
     for (; o != first_map_to_evacuate_; o = it.next()) {
-      it.has_next();  // Must be called for side-effects, see bug 586.
-      ASSERT(it.has_next());
+      ASSERT(o != NULL);
       Map* map = reinterpret_cast<Map*>(o);
       ASSERT(!map->IsMarked());
       ASSERT(!map->IsOverflowed());
@@ -1309,10 +1309,8 @@ class MapCompact {
 
   void UpdateMapPointersInLargeObjectSpace() {
     LargeObjectIterator it(Heap::lo_space());
-    while (true) {
-      if (!it.has_next()) break;
-      UpdateMapPointersInObject(it.next());
-    }
+    for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+      UpdateMapPointersInObject(obj);
   }
 
   void Finish() {
@@ -1355,9 +1353,8 @@ class MapCompact {
 
   static Map* NextMap(MapIterator* it, HeapObject* last, bool live) {
     while (true) {
-      it->has_next();  // Must be called for side-effects, see bug 586.
-      ASSERT(it->has_next());
       HeapObject* next = it->next();
+      ASSERT(next != NULL);
       if (next == last)
         return NULL;
       ASSERT(!next->IsOverflowed());
@@ -1446,8 +1443,9 @@ class MapCompact {
     if (!FLAG_enable_slow_asserts)
       return;
 
-    while (map_to_evacuate_it_.has_next())
-      ASSERT(FreeListNode::IsFreeListNode(map_to_evacuate_it_.next()));
+    for (HeapObject* obj = map_to_evacuate_it_.next();
+         obj != NULL; obj = map_to_evacuate_it_.next())
+      ASSERT(FreeListNode::IsFreeListNode(obj));
   }
 #endif
 };
@@ -1480,7 +1478,8 @@ void MarkCompactCollector::SweepSpaces() {
 
     map_compact.FinishMapSpace();
     PagedSpaces spaces;
-    while (PagedSpace* space = spaces.next()) {
+    for (PagedSpace* space = spaces.next();
+         space != NULL; space = spaces.next()) {
       if (space == Heap::map_space()) continue;
       map_compact.UpdateMapPointersInPagedSpace(space);
     }
@@ -1655,7 +1654,8 @@ void MarkCompactCollector::UpdatePointers() {
 
   // Large objects do not move, the map word can be updated directly.
   LargeObjectIterator it(Heap::lo_space());
-  while (it.has_next()) UpdatePointersInNewObject(it.next());
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+    UpdatePointersInNewObject(obj);
 
   USE(live_maps);
   USE(live_pointer_olds);
@@ -1819,7 +1819,8 @@ void MarkCompactCollector::RelocateObjects() {
   Page::set_rset_state(Page::IN_USE);
 #endif
   PagedSpaces spaces;
-  while (PagedSpace* space = spaces.next()) space->MCCommitRelocationInfo();
+  for (PagedSpace* space = spaces.next(); space != NULL; space = spaces.next())
+    space->MCCommitRelocationInfo();
 }
 
 

src/runtime.cc

@@ -7212,9 +7212,8 @@ Object* Runtime::FindSharedFunctionInfoInScript(Handle<Script> script,
   Handle<SharedFunctionInfo> last;
   while (!done) {
     HeapIterator iterator;
-    while (iterator.has_next()) {
-      HeapObject* obj = iterator.next();
-      ASSERT(obj != NULL);
+    for (HeapObject* obj = iterator.next();
+         obj != NULL; obj = iterator.next()) {
       if (obj->IsSharedFunctionInfo()) {
         Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(obj));
         if (shared->script() == *script) {
@@ -7670,10 +7669,10 @@ static int DebugReferencedBy(JSObject* target,
   int count = 0;
   JSObject* last = NULL;
   HeapIterator iterator;
-  while (iterator.has_next() &&
+  HeapObject* heap_obj = NULL;
+  while (((heap_obj = iterator.next()) != NULL) &&
          (max_references == 0 || count < max_references)) {
     // Only look at all JSObjects.
-    HeapObject* heap_obj = iterator.next();
     if (heap_obj->IsJSObject()) {
       // Skip context extension objects and argument arrays as these are
       // checked in the context of functions using them.
@@ -7783,10 +7782,10 @@ static int DebugConstructedBy(JSFunction* constructor, int max_references,
   // Iterate the heap.
   int count = 0;
   HeapIterator iterator;
-  while (iterator.has_next() &&
+  HeapObject* heap_obj = NULL;
+  while (((heap_obj = iterator.next()) != NULL) &&
          (max_references == 0 || count < max_references)) {
     // Only look at all JSObjects.
-    HeapObject* heap_obj = iterator.next();
     if (heap_obj->IsJSObject()) {
       JSObject* obj = JSObject::cast(heap_obj);
       if (obj->map()->constructor() == constructor) {
@@ -7934,8 +7933,8 @@ static Handle<Object> Runtime_GetScriptFromScriptName(
   // script data.
   Handle<Script> script;
   HeapIterator iterator;
-  while (script.is_null() && iterator.has_next()) {
-    HeapObject* obj = iterator.next();
+  HeapObject* obj = NULL;
+  while (script.is_null() && ((obj = iterator.next()) != NULL)) {
     // If a script is found check if it has the script data requested.
     if (obj->IsScript()) {
       if (Script::cast(obj)->name()->IsString()) {

src/spaces-inl.h

@@ -35,32 +35,6 @@ namespace v8 {
 namespace internal {
 
 
-// -----------------------------------------------------------------------------
-// HeapObjectIterator
-
-bool HeapObjectIterator::has_next() {
-  if (cur_addr_ < cur_limit_) {
-    return true;  // common case
-  }
-  ASSERT(cur_addr_ == cur_limit_);
-  return HasNextInNextPage();  // slow path
-}
-
-
-HeapObject* HeapObjectIterator::next() {
-  ASSERT(has_next());
-
-  HeapObject* obj = HeapObject::FromAddress(cur_addr_);
-  int obj_size = (size_func_ == NULL) ? obj->Size() : size_func_(obj);
-  ASSERT_OBJECT_SIZE(obj_size);
-
-  cur_addr_ += obj_size;
-  ASSERT(cur_addr_ <= cur_limit_);
-
-  return obj;
-}
-
-
 // -----------------------------------------------------------------------------
 // PageIterator
 

src/spaces.cc

@@ -82,8 +82,8 @@ void HeapObjectIterator::Initialize(Address cur, Address end,
 }
 
 
-bool HeapObjectIterator::HasNextInNextPage() {
-  if (cur_addr_ == end_addr_) return false;
+HeapObject* HeapObjectIterator::FromNextPage() {
+  if (cur_addr_ == end_addr_) return NULL;
 
   Page* cur_page = Page::FromAllocationTop(cur_addr_);
   cur_page = cur_page->next_page();
@@ -92,12 +92,12 @@ bool HeapObjectIterator::HasNextInNextPage() {
   cur_addr_ = cur_page->ObjectAreaStart();
   cur_limit_ = (cur_page == end_page_) ? end_addr_ : cur_page->AllocationTop();
 
-  if (cur_addr_ == end_addr_) return false;
+  if (cur_addr_ == end_addr_) return NULL;
   ASSERT(cur_addr_ < cur_limit_);
 #ifdef DEBUG
   Verify();
 #endif
-  return true;
+  return FromCurrentPage();
 }
 
 
@@ -1437,7 +1437,8 @@ void NewSpace::ClearHistograms() {
 void NewSpace::CollectStatistics() {
   ClearHistograms();
   SemiSpaceIterator it(this);
-  while (it.has_next()) RecordAllocation(it.next());
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next())
+    RecordAllocation(obj);
 }
 
 
@@ -2054,8 +2055,7 @@ static void CollectCommentStatistics(RelocIterator* it) {
 // - by code comment
 void PagedSpace::CollectCodeStatistics() {
   HeapObjectIterator obj_it(this);
-  while (obj_it.has_next()) {
-    HeapObject* obj = obj_it.next();
+  for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       code_kind_statistics[code->kind()] += code->Size();
@@ -2157,7 +2157,8 @@ void OldSpace::ReportStatistics() {
 
   ClearHistograms();
   HeapObjectIterator obj_it(this);
-  while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); }
+  for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next())
+    CollectHistogramInfo(obj);
   ReportHistogram(true);
 }
 
@@ -2393,7 +2394,8 @@ void FixedSpace::ReportStatistics() {
 
   ClearHistograms();
   HeapObjectIterator obj_it(this);
-  while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); }
+  for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next())
+    CollectHistogramInfo(obj);
   ReportHistogram(false);
 }
 
@@ -2462,7 +2464,8 @@ LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space,
 
 
 HeapObject* LargeObjectIterator::next() {
-  ASSERT(has_next());
+  if (current_ == NULL) return NULL;
+
   HeapObject* object = current_->GetObject();
   current_ = current_->next();
   return object;
@@ -2639,8 +2642,7 @@ void LargeObjectSpace::ClearRSet() {
   ASSERT(Page::is_rset_in_use());
 
   LargeObjectIterator it(this);
-  while (it.has_next()) {
-    HeapObject* object = it.next();
+  for (HeapObject* object = it.next(); object != NULL; object = it.next()) {
     // We only have code, sequential strings, or fixed arrays in large
     // object space, and only fixed arrays need remembered set support.
     if (object->IsFixedArray()) {
@@ -2668,11 +2670,10 @@ void LargeObjectSpace::IterateRSet(ObjectSlotCallback copy_object_func) {
       30);
 
   LargeObjectIterator it(this);
-  while (it.has_next()) {
+  for (HeapObject* object = it.next(); object != NULL; object = it.next()) {
     // We only have code, sequential strings, or fixed arrays in large
     // object space, and only fixed arrays can possibly contain pointers to
     // the young generation.
-    HeapObject* object = it.next();
     if (object->IsFixedArray()) {
       // Iterate the normal page remembered set range.
       Page* page = Page::FromAddress(object->address());
@@ -2798,8 +2799,8 @@ void LargeObjectSpace::Verify() {
 
 void LargeObjectSpace::Print() {
   LargeObjectIterator it(this);
-  while (it.has_next()) {
-    it.next()->Print();
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) {
+    obj->Print();
   }
 }
 
@@ -2809,9 +2810,9 @@ void LargeObjectSpace::ReportStatistics() {
   int num_objects = 0;
   ClearHistograms();
   LargeObjectIterator it(this);
-  while (it.has_next()) {
+  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) {
     num_objects++;
-    CollectHistogramInfo(it.next());
+    CollectHistogramInfo(obj);
   }
 
   PrintF("  number of objects %d\n", num_objects);
@@ -2821,8 +2822,7 @@ void LargeObjectSpace::ReportStatistics() {
 
 void LargeObjectSpace::CollectCodeStatistics() {
   LargeObjectIterator obj_it(this);
-  while (obj_it.has_next()) {
-    HeapObject* obj = obj_it.next();
+  for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       code_kind_statistics[code->kind()] += code->Size();
@@ -2833,8 +2833,7 @@ void LargeObjectSpace::CollectCodeStatistics() {
 
 void LargeObjectSpace::PrintRSet() {
   LargeObjectIterator it(this);
-  while (it.has_next()) {
-    HeapObject* object = it.next();
+  for (HeapObject* object = it.next(); object != NULL; object = it.next()) {
     if (object->IsFixedArray()) {
       Page* page = Page::FromAddress(object->address());
 

src/spaces.h

@@ -597,15 +597,14 @@ class MemoryAllocator : public AllStatic {
 // Interface for heap object iterator to be implemented by all object space
 // object iterators.
 //
-// NOTE: The space specific object iterators also implements the own has_next()
-//       and next() methods which are used to avoid using virtual functions
+// NOTE: The space specific object iterators also implements the own next()
+//       method which is used to avoid using virtual functions
 //       iterating a specific space.
 
 class ObjectIterator : public Malloced {
  public:
   virtual ~ObjectIterator() { }
 
-  virtual bool has_next_object() = 0;
   virtual HeapObject* next_object() = 0;
 };
 
@@ -645,11 +644,11 @@ class HeapObjectIterator: public ObjectIterator {
                      Address start,
                      HeapObjectCallback size_func);
 
-  inline bool has_next();
-  inline HeapObject* next();
+  inline HeapObject* next() {
+    return (cur_addr_ < cur_limit_) ? FromCurrentPage() : FromNextPage();
+  }
 
   // implementation of ObjectIterator.
-  virtual bool has_next_object() { return has_next(); }
   virtual HeapObject* next_object() { return next(); }
 
  private:
@@ -659,9 +658,21 @@ class HeapObjectIterator: public ObjectIterator {
   HeapObjectCallback size_func_;  // size function
   Page* end_page_;  // caches the page of the end address
 
-  // Slow path of has_next, checks whether there are more objects in
-  // the next page.
-  bool HasNextInNextPage();
+  HeapObject* FromCurrentPage() {
+    ASSERT(cur_addr_ < cur_limit_);
+
+    HeapObject* obj = HeapObject::FromAddress(cur_addr_);
+    int obj_size = (size_func_ == NULL) ? obj->Size() : size_func_(obj);
+    ASSERT_OBJECT_SIZE(obj_size);
+
+    cur_addr_ += obj_size;
+    ASSERT(cur_addr_ <= cur_limit_);
+
+    return obj;
+  }
+
+  // Slow path of next, goes into the next page.
+  HeapObject* FromNextPage();
 
   // Initializes fields.
   void Initialize(Address start, Address end, HeapObjectCallback size_func);
@@ -1206,10 +1217,8 @@ class SemiSpaceIterator : public ObjectIterator {
   SemiSpaceIterator(NewSpace* space, HeapObjectCallback size_func);
   SemiSpaceIterator(NewSpace* space, Address start);
 
-  bool has_next() {return current_ < limit_; }
-
   HeapObject* next() {
-    ASSERT(has_next());
+    if (current_ == limit_) return NULL;
 
     HeapObject* object = HeapObject::FromAddress(current_);
     int size = (size_func_ == NULL) ? object->Size() : size_func_(object);
@@ -1219,7 +1228,6 @@ class SemiSpaceIterator : public ObjectIterator {
   }
 
   // Implementation of the ObjectIterator functions.
-  virtual bool has_next_object() { return has_next(); }
   virtual HeapObject* next_object() { return next(); }
 
  private:
@@ -1800,11 +1808,9 @@ class MapSpace : public FixedSpace {
     int pages_left = live_maps / kMapsPerPage;
     PageIterator it(this, PageIterator::ALL_PAGES);
     while (pages_left-- > 0) {
-      it.has_next();  // Must be called for side-effects, see bug 586.
       ASSERT(it.has_next());
       it.next()->ClearRSet();
     }
-    it.has_next();  // Must be called for side-effects, see bug 586.
     ASSERT(it.has_next());
     Page* top_page = it.next();
     top_page->ClearRSet();
@@ -2054,11 +2060,9 @@ class LargeObjectIterator: public ObjectIterator {
   explicit LargeObjectIterator(LargeObjectSpace* space);
   LargeObjectIterator(LargeObjectSpace* space, HeapObjectCallback size_func);
 
-  bool has_next() { return current_ != NULL; }
   HeapObject* next();
 
   // implementation of ObjectIterator.
-  virtual bool has_next_object() { return has_next(); }
   virtual HeapObject* next_object() { return next(); }
 
  private:

test/cctest/test-api.cc

@@ -6236,8 +6236,16 @@ THREADED_TEST(LockUnlockLock) {
 }
 
 
-static int GetSurvivingGlobalObjectsCount() {
+static int GetGlobalObjectsCount() {
   int count = 0;
+  v8::internal::HeapIterator it;
+  for (i::HeapObject* object = it.next(); object != NULL; object = it.next())
+    if (object->IsJSGlobalObject()) count++;
+  return count;
+}
+
+
+static int GetSurvivingGlobalObjectsCount() {
   // We need to collect all garbage twice to be sure that everything
   // has been collected.  This is because inline caches are cleared in
   // the first garbage collection but some of the maps have already
@@ -6245,13 +6253,7 @@ static int GetSurvivingGlobalObjectsCount() {
   // collected until the second garbage collection.
   v8::internal::Heap::CollectAllGarbage(false);
   v8::internal::Heap::CollectAllGarbage(false);
-  v8::internal::HeapIterator it;
-  while (it.has_next()) {
-    v8::internal::HeapObject* object = it.next();
-    if (object->IsJSGlobalObject()) {
-      count++;
-    }
-  }
+  int count = GetGlobalObjectsCount();
 #ifdef DEBUG
   if (count > 0) v8::internal::Heap::TracePathToGlobal();
 #endif
@@ -8621,17 +8623,6 @@ THREADED_TEST(SpaghettiStackReThrow) {
 }
 
 
-static int GetGlobalObjectsCount() {
-  int count = 0;
-  v8::internal::HeapIterator it;
-  while (it.has_next()) {
-    v8::internal::HeapObject* object = it.next();
-    if (object->IsJSGlobalObject()) count++;
-  }
-  return count;
-}
-
-
 TEST(Regress528) {
   v8::V8::Initialize();
 

test/cctest/test-debug.cc

@@ -413,9 +413,7 @@ void CheckDebuggerUnloaded(bool check_functions) {
 
   // Iterate the head and check that there are no debugger related objects left.
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    CHECK(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     CHECK(!obj->IsDebugInfo());
     CHECK(!obj->IsBreakPointInfo());
 

test/cctest/test-heap-profiler.cc

@@ -64,10 +64,8 @@ TEST(ConstructorProfile) {
   ConstructorHeapProfileTestHelper cons_profile;
   i::AssertNoAllocation no_alloc;
   i::HeapIterator iterator;
-  while (iterator.has_next()) {
-    i::HeapObject* obj = iterator.next();
+  for (i::HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next())
     cons_profile.CollectStats(obj);
-  }
   CHECK_EQ(0, cons_profile.f_count());
   cons_profile.PrintStats();
   CHECK_EQ(2, cons_profile.f_count());
@@ -375,10 +373,8 @@ TEST(RetainerProfile) {
   RetainerHeapProfile ret_profile;
   i::AssertNoAllocation no_alloc;
   i::HeapIterator iterator;
-  while (iterator.has_next()) {
-    i::HeapObject* obj = iterator.next();
+  for (i::HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next())
     ret_profile.CollectStats(obj);
-  }
   RetainerProfilePrinter printer;
   ret_profile.DebugPrintStats(&printer);
   const char* retainers_of_a = printer.GetRetainers("A");

test/cctest/test-heap.cc

@@ -746,16 +746,13 @@ static int ObjectsFoundInHeap(Handle<Object> objs[], int size) {
   // Count the number of objects found in the heap.
   int found_count = 0;
   HeapIterator iterator;
-  while (iterator.has_next()) {
-    HeapObject* obj = iterator.next();
-    CHECK(obj != NULL);
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     for (int i = 0; i < size; i++) {
       if (*objs[i] == obj) {
         found_count++;
       }
     }
   }
-  CHECK(!iterator.has_next());
   return found_count;
 }