[heap] Decouple SpaceIterator from ObjectIterator.

src/heap/spaces.cc

 // 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.
 
 #include "src/heap/spaces.h"
 
 #include <utility>
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
@@ skipping 1413 matching lines @@
   if (page->next_chunk() != NULL) {
     DCHECK(page->prev_chunk() != NULL);
     page->Unlink();
   }
 
   AccountUncommitted(static_cast<intptr_t>(page->size()));
   accounting_stats_.ShrinkSpace(page->area_size());
   heap()->memory_allocator()->Free<MemoryAllocator::kPreFreeAndQueue>(page);
 }
 
+std::unique_ptr<ObjectIterator> PagedSpace::GetObjectIterator() {
+  return std::unique_ptr<ObjectIterator>(new HeapObjectIterator(this));
+}
+
 #ifdef DEBUG
 void PagedSpace::Print() {}
 #endif
 
 #ifdef VERIFY_HEAP
 void PagedSpace::Verify(ObjectVisitor* visitor) {
   bool allocation_pointer_found_in_space =
       (allocation_info_.top() == allocation_info_.limit());
   for (Page* page : *this) {
     CHECK(page->owner() == this);
@@ skipping 375 matching lines @@
   if (top_on_previous_step_) {
     int bytes_allocated = static_cast<int>(top - top_on_previous_step_);
     for (int i = 0; i < allocation_observers_->length(); ++i) {
       (*allocation_observers_)[i]->AllocationStep(bytes_allocated, soon_object,
                                                   size);
     }
     top_on_previous_step_ = new_top;
   }
 }
 
+std::unique_ptr<ObjectIterator> NewSpace::GetObjectIterator() {
+  return std::unique_ptr<ObjectIterator>(new SemiSpaceIterator(this));
+}
+
 #ifdef VERIFY_HEAP
 // We do not use the SemiSpaceIterator because verification doesn't assume
 // that it works (it depends on the invariants we are checking).
 void NewSpace::Verify() {
   // The allocation pointer should be in the space or at the very end.
   DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 
   // There should be objects packed in from the low address up to the
   // allocation pointer.
   Address current = to_space_.first_page()->area_start();
@@ skipping 273 matching lines @@
       allocation_info_.Reset(to_space_.page_high(), to_space_.page_high());
     }
   }
   if (FLAG_trace_gc_verbose) {
     PrintIsolate(heap()->isolate(),
                  "Sealing intermediate generation: bytes_lost=%zu\n",
                  fragmentation_in_intermediate_generation_);
   }
 }
 
+std::unique_ptr<ObjectIterator> SemiSpace::GetObjectIterator() {
+  // Use the NewSpace::NewObjectIterator to iterate the ToSpace.
+  UNREACHABLE();
+  return std::unique_ptr<ObjectIterator>();
+}
+
 #ifdef DEBUG
 void SemiSpace::Print() {}
 #endif
 
 #ifdef VERIFY_HEAP
 void SemiSpace::Verify() {
   bool is_from_space = (id_ == kFromSpace);
   Page* page = anchor_.next_page();
   CHECK(anchor_.owner() == this);
   while (page != &anchor_) {
@@ skipping 1031 matching lines @@
   Address address = object->address();
   MemoryChunk* chunk = MemoryChunk::FromAddress(address);
 
   bool owned = (chunk->owner() == this);
 
   SLOW_DCHECK(!owned || FindObject(address)->IsHeapObject());
 
   return owned;
 }
 
+std::unique_ptr<ObjectIterator> LargeObjectSpace::GetObjectIterator() {
+  return std::unique_ptr<ObjectIterator>(new LargeObjectIterator(this));
+}
 
 #ifdef VERIFY_HEAP
 // We do not assume that the large object iterator works, because it depends
 // on the invariants we are checking during verification.
 void LargeObjectSpace::Verify() {
   for (LargePage* chunk = first_page_; chunk != NULL;
        chunk = chunk->next_page()) {
     // Each chunk contains an object that starts at the large object page's
     // object area start.
     HeapObject* object = chunk->GetObject();
@@ skipping 81 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8