Remove conservative sweeping.

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/v8.h"
 
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
 #include "src/macro-assembler.h"
@@ skipping 29 matching lines @@
                                        HeapObjectCallback size_func) {
   Space* owner = page->owner();
   DCHECK(owner == page->heap()->old_pointer_space() ||
          owner == page->heap()->old_data_space() ||
          owner == page->heap()->map_space() ||
          owner == page->heap()->cell_space() ||
          owner == page->heap()->property_cell_space() ||
          owner == page->heap()->code_space());
   Initialize(reinterpret_cast<PagedSpace*>(owner), page->area_start(),
              page->area_end(), kOnePageOnly, size_func);
-  DCHECK(page->WasSweptPrecisely() ||
-         (static_cast<PagedSpace*>(owner)->swept_precisely() &&
-          page->SweepingCompleted()));
+  DCHECK(page->WasSwept() || page->SweepingCompleted());
 }
 
 
 void HeapObjectIterator::Initialize(PagedSpace* space, Address cur, Address end,
                                     HeapObjectIterator::PageMode mode,
                                     HeapObjectCallback size_f) {
-  // Check that we actually can iterate this space.
-  DCHECK(space->swept_precisely());
-
   space_ = space;
   cur_addr_ = cur;
   cur_end_ = end;
   page_mode_ = mode;
   size_func_ = size_f;
 }
 
 
 // We have hit the end of the page and should advance to the next block of
 // objects.  This happens at the end of the page.
 bool HeapObjectIterator::AdvanceToNextPage() {
   DCHECK(cur_addr_ == cur_end_);
   if (page_mode_ == kOnePageOnly) return false;
   Page* cur_page;
   if (cur_addr_ == NULL) {
     cur_page = space_->anchor();
   } else {
     cur_page = Page::FromAddress(cur_addr_ - 1);
     DCHECK(cur_addr_ == cur_page->area_end());
   }
   cur_page = cur_page->next_page();
   if (cur_page == space_->anchor()) return false;
   cur_addr_ = cur_page->area_start();
   cur_end_ = cur_page->area_end();
-  DCHECK(cur_page->WasSweptPrecisely() ||
-         (static_cast<PagedSpace*>(cur_page->owner())->swept_precisely() &&
-          cur_page->SweepingCompleted()));
+  DCHECK(cur_page->WasSwept() || cur_page->SweepingCompleted());
   return true;
 }
 
 
 // -----------------------------------------------------------------------------
 // CodeRange
 
 
 CodeRange::CodeRange(Isolate* isolate)
     : isolate_(isolate),
@@ skipping 353 matching lines @@
   chunk->high_water_mark_ = static_cast<int>(area_start - base);
   chunk->set_parallel_sweeping(SWEEPING_DONE);
   chunk->available_in_small_free_list_ = 0;
   chunk->available_in_medium_free_list_ = 0;
   chunk->available_in_large_free_list_ = 0;
   chunk->available_in_huge_free_list_ = 0;
   chunk->non_available_small_blocks_ = 0;
   chunk->ResetLiveBytes();
   Bitmap::Clear(chunk);
   chunk->initialize_scan_on_scavenge(false);
-  chunk->SetFlag(WAS_SWEPT_PRECISELY);
+  chunk->SetFlag(WAS_SWEPT);
 
   DCHECK(OFFSET_OF(MemoryChunk, flags_) == kFlagsOffset);
   DCHECK(OFFSET_OF(MemoryChunk, live_byte_count_) == kLiveBytesOffset);
 
   if (executable == EXECUTABLE) {
     chunk->SetFlag(IS_EXECUTABLE);
   }
 
   if (owner == heap->old_data_space()) {
     chunk->SetFlag(CONTAINS_ONLY_DATA);
@@ skipping 406 matching lines @@
 }
 
 
 // -----------------------------------------------------------------------------
 // PagedSpace implementation
 
 PagedSpace::PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
                        Executability executable)
     : Space(heap, id, executable),
       free_list_(this),
-      swept_precisely_(true),
       unswept_free_bytes_(0),
       end_of_unswept_pages_(NULL),
       emergency_memory_(NULL) {
   if (id == CODE_SPACE) {
     area_size_ = heap->isolate()->memory_allocator()->CodePageAreaSize();
   } else {
     area_size_ = Page::kPageSize - Page::kObjectStartOffset;
   }
   max_capacity_ =
       (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize) * AreaSize();
@@ skipping 29 matching lines @@
   size_t size = 0;
   PageIterator it(this);
   while (it.has_next()) {
     size += it.next()->CommittedPhysicalMemory();
   }
   return size;
 }
 
 
 Object* PagedSpace::FindObject(Address addr) {
-  // Note: this function can only be called on precisely swept spaces.
+  // Note: this function can only be called on iterable spaces.
   DCHECK(!heap()->mark_compact_collector()->in_use());
 
   if (!Contains(addr)) return Smi::FromInt(0);  // Signaling not found.
 
   Page* p = Page::FromAddress(addr);
   HeapObjectIterator it(p, NULL);
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     Address cur = obj->address();
     Address next = cur + obj->Size();
     if ((cur <= addr) && (addr < next)) return obj;
@@ skipping 172 matching lines @@
   emergency_memory_ = NULL;
 }
 
 
 #ifdef DEBUG
 void PagedSpace::Print() {}
 #endif
 
 #ifdef VERIFY_HEAP
 void PagedSpace::Verify(ObjectVisitor* visitor) {
-  // We can only iterate over the pages if they were swept precisely.
-  if (!swept_precisely_) return;
-
   bool allocation_pointer_found_in_space =
       (allocation_info_.top() == allocation_info_.limit());
   PageIterator page_iterator(this);
   while (page_iterator.has_next()) {
     Page* page = page_iterator.next();
     CHECK(page->owner() == this);
     if (page == Page::FromAllocationTop(allocation_info_.top())) {
       allocation_pointer_found_in_space = true;
     }
-    CHECK(page->WasSweptPrecisely());
+    CHECK(page->WasSwept());
     HeapObjectIterator it(page, NULL);
     Address end_of_previous_object = page->area_start();
     Address top = page->area_end();
     int black_size = 0;
     for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
       CHECK(end_of_previous_object <= object->address());
 
       // The first word should be a map, and we expect all map pointers to
       // be in map space.
       Map* map = object->map();
@@ skipping 1575 matching lines @@
 
 void PagedSpace::ReportStatistics() {
   int pct = static_cast<int>(Available() * 100 / Capacity());
   PrintF("  capacity: %" V8_PTR_PREFIX
          "d"
          ", waste: %" V8_PTR_PREFIX
          "d"
          ", available: %" V8_PTR_PREFIX "d, %%%d\n",
          Capacity(), Waste(), Available(), pct);
 
-  if (!swept_precisely_) return;
   if (heap()->mark_compact_collector()->sweeping_in_progress()) {
     heap()->mark_compact_collector()->EnsureSweepingCompleted();
   }
   ClearHistograms(heap()->isolate());
   HeapObjectIterator obj_it(this);
   for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next())
     CollectHistogramInfo(obj);
   ReportHistogram(heap()->isolate(), true);
 }
 #endif
@@ skipping 356 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }
 }  // namespace v8::internal