[heap] Use PageIterator in HeapObjectIterator

src/heap/spaces.h

 // Copyright 2011 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_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include <list>
 
 #include "src/allocation.h"
@@ skipping 1554 matching lines @@
 // Interface for heap object iterator to be implemented by all object space
 // object iterators.
 //
 // 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 HeapObject* next_object() = 0;
+  virtual HeapObject* Next() = 0;
 };
 
+template <class PAGE_TYPE>
+class PageIteratorImpl

[Michael Lippautz, 2016/06/23 19:43:14]

Just moved up.

+    : public std::iterator<std::forward_iterator_tag, PAGE_TYPE> {

[brucedawson, 2017/06/14 22:07:13]

It turns out that std::iterator is deprecated in C++ 17, and internal builds of
VC++ 2017 have started issuing deprecation warnings. We should think about
removing our usage of std::iterator.

An example removal from LLVM can be found here:

https://reviews.llvm.org/D34223

+ public:
+  explicit PageIteratorImpl(PAGE_TYPE* p) : p_(p) {}
+  PageIteratorImpl(const PageIteratorImpl<PAGE_TYPE>& other) : p_(other.p_) {}
+  PAGE_TYPE* operator*() { return p_; }
+  bool operator==(const PageIteratorImpl<PAGE_TYPE>& rhs) {
+    return rhs.p_ == p_;
+  }
+  bool operator!=(const PageIteratorImpl<PAGE_TYPE>& rhs) {
+    return rhs.p_ != p_;
+  }
+  inline PageIteratorImpl<PAGE_TYPE>& operator++();
+  inline PageIteratorImpl<PAGE_TYPE> operator++(int);
+
+ private:
+  PAGE_TYPE* p_;
+};
+
+typedef PageIteratorImpl<Page> PageIterator;
+typedef PageIteratorImpl<LargePage> LargePageIterator;
+
+class PageRange {
+ public:
+  typedef PageIterator iterator;
+  PageRange(Page* begin, Page* end) : begin_(begin), end_(end) {}
+  explicit PageRange(Page* page) : PageRange(page, page->next_page()) {}
+  iterator begin() { return iterator(begin_); }
+  iterator end() { return iterator(end_); }
+
+ private:
+  Page* begin_;
+  Page* end_;
+};
 
 // -----------------------------------------------------------------------------
 // Heap object iterator in new/old/map spaces.
 //
 // A HeapObjectIterator iterates objects from the bottom of the given space
 // to its top or from the bottom of the given page to its top.
 //
 // If objects are allocated in the page during iteration the iterator may
 // or may not iterate over those objects.  The caller must create a new
 // iterator in order to be sure to visit these new objects.
 class HeapObjectIterator : public ObjectIterator {
  public:
   // Creates a new object iterator in a given space.
   explicit HeapObjectIterator(PagedSpace* space);
   explicit HeapObjectIterator(Page* page);
 
   // Advance to the next object, skipping free spaces and other fillers and
   // skipping the special garbage section of which there is one per space.
-  // Returns NULL when the iteration has ended.
-  inline HeapObject* Next();
-  inline HeapObject* next_object() override;
+  // Returns nullptr when the iteration has ended.
+  inline HeapObject* Next() override;
 
  private:
-  enum PageMode { kOnePageOnly, kAllPagesInSpace };
-
-  Address cur_addr_;              // Current iteration point.
-  Address cur_end_;               // End iteration point.
-  PagedSpace* space_;
-  PageMode page_mode_;
-
   // Fast (inlined) path of next().
   inline HeapObject* FromCurrentPage();
 
   // Slow path of next(), goes into the next page.  Returns false if the
   // iteration has ended.
   bool AdvanceToNextPage();
 
-  // Initializes fields.
-  inline void Initialize(PagedSpace* owner, Address start, Address end,
-                         PageMode mode);
+  Address cur_addr_;  // Current iteration point.
+  Address cur_end_;   // End iteration point.
+  PagedSpace* space_;
+  PageRange page_range_;
+  PageRange::iterator current_page_;
 };
 
 
 // -----------------------------------------------------------------------------
 // A space has a circular list of pages. The next page can be accessed via
 // Page::next_page() call.
 
 // An abstraction of allocation and relocation pointers in a page-structured
 // space.
 class AllocationInfo {
@@ skipping 431 matching lines @@
 
  private:
   LocalAllocationBuffer(Heap* heap, AllocationInfo allocation_info);
 
   void Close();
 
   Heap* heap_;
   AllocationInfo allocation_info_;
 };
 
-template <class PAGE_TYPE>
-class PageIteratorImpl
-    : public std::iterator<std::forward_iterator_tag, PAGE_TYPE> {
+class NewSpacePageRange {
  public:
-  explicit PageIteratorImpl(PAGE_TYPE* p) : p_(p) {}
-  PageIteratorImpl(const PageIteratorImpl<PAGE_TYPE>& other) : p_(other.p_) {}
-  PAGE_TYPE* operator*() { return p_; }
-  bool operator==(const PageIteratorImpl<PAGE_TYPE>& rhs) {
-    return rhs.p_ == p_;
-  }
-  bool operator!=(const PageIteratorImpl<PAGE_TYPE>& rhs) {
-    return rhs.p_ != p_;
-  }
-  inline PageIteratorImpl<PAGE_TYPE>& operator++();
-  inline PageIteratorImpl<PAGE_TYPE> operator++(int);
+  typedef PageRange::iterator iterator;
+  inline NewSpacePageRange(Address start, Address limit);
+  iterator begin() { return range_.begin(); }
+  iterator end() { return range_.end(); }
 
  private:
-  PAGE_TYPE* p_;
-};
-
-typedef PageIteratorImpl<Page> PageIterator;
-typedef PageIteratorImpl<LargePage> LargePageIterator;
-
-class NewSpacePageRange {
- public:
-  typedef PageIterator iterator;
-
-  inline NewSpacePageRange(Address start, Address limit);
-
-  iterator begin() { return iterator(Page::FromAddress(start_)); }
-  iterator end() {
-    return iterator(Page::FromAllocationAreaAddress(limit_)->next_page());
-  }
-
- private:
-  Address start_;
-  Address limit_;
+  PageRange range_;
 };
 
 class PagedSpace : public Space {
  public:
   typedef PageIterator iterator;
 
   static const intptr_t kCompactionMemoryWanted = 500 * KB;
 
   // Creates a space with an id.
   PagedSpace(Heap* heap, AllocationSpace id, Executability executable);
@@ skipping 474 matching lines @@
 // A SemiSpaceIterator is an ObjectIterator that iterates over the active
 // semispace of the heap's new space.  It iterates over the objects in the
 // semispace from a given start address (defaulting to the bottom of the
 // semispace) to the top of the semispace.  New objects allocated after the
 // iterator is created are not iterated.
 class SemiSpaceIterator : public ObjectIterator {
  public:
   // Create an iterator over the allocated objects in the given to-space.
   explicit SemiSpaceIterator(NewSpace* space);
 
-  inline HeapObject* Next();
-
-  // Implementation of the ObjectIterator functions.
-  inline HeapObject* next_object() override;
+  inline HeapObject* Next() override;
 
  private:
   void Initialize(Address start, Address end);
 
   // The current iteration point.
   Address current_;
   // The end of iteration.
   Address limit_;
 };
 
@@ skipping 501 matching lines @@
   base::HashMap chunk_map_;
 
   friend class LargeObjectIterator;
 };
 
 
 class LargeObjectIterator : public ObjectIterator {
  public:
   explicit LargeObjectIterator(LargeObjectSpace* space);
 
-  HeapObject* Next();
-
-  // implementation of ObjectIterator.
-  virtual HeapObject* next_object() { return Next(); }
+  HeapObject* Next() override;
 
  private:
   LargePage* current_;
 };
 
 // Iterates over the chunks (pages and large object pages) that can contain
 // pointers to new space or to evacuation candidates.
 class MemoryChunkIterator BASE_EMBEDDED {
  public:
   inline explicit MemoryChunkIterator(Heap* heap);
@@ skipping 28 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_