Reland of "heap] Fix Sweeper::IsSweepingCompleted"

src/heap/mark-compact.cc

 // Copyright 2012 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/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 490 matching lines @@
   if (FLAG_concurrent_sweeping) {
     ForAllSweepingSpaces([this](AllocationSpace space) {
       if (space == NEW_SPACE) return;
       StartSweepingHelper(space);
     });
   }
 }
 
 void MarkCompactCollector::Sweeper::StartSweepingHelper(
     AllocationSpace space_to_start) {
-  num_sweeping_tasks_++;
+  num_sweeping_tasks_.Increment(1);
   V8::GetCurrentPlatform()->CallOnBackgroundThread(
       new SweeperTask(this, &pending_sweeper_tasks_semaphore_, space_to_start),
       v8::Platform::kShortRunningTask);
 }
 
 void MarkCompactCollector::Sweeper::SweepOrWaitUntilSweepingCompleted(
     Page* page) {
   PagedSpace* owner = reinterpret_cast<PagedSpace*>(page->owner());
   if (!page->SweepingDone()) {
     ParallelSweepPage(page, owner);
@@ skipping 26 matching lines @@
   if (!sweeping_in_progress_) return;
 
   // If sweeping is not completed or not running at all, we try to complete it
   // here.
   if (!FLAG_concurrent_sweeping || !IsSweepingCompleted()) {
     ForAllSweepingSpaces(
         [this](AllocationSpace space) { ParallelSweepSpace(space, 0); });
   }
 
   if (FLAG_concurrent_sweeping) {
-    while (num_sweeping_tasks_ > 0) {
+    while (num_sweeping_tasks_.Value() > 0) {
       pending_sweeper_tasks_semaphore_.Wait();
-      num_sweeping_tasks_--;
+      num_sweeping_tasks_.Increment(-1);
     }
   }
 
   ForAllSweepingSpaces(
       [this](AllocationSpace space) { DCHECK(sweeping_list_[space].empty()); });
   late_pages_ = false;
   sweeping_in_progress_ = false;
 }
 
 void MarkCompactCollector::EnsureSweepingCompleted() {
   if (!sweeper().sweeping_in_progress()) return;
 
   sweeper().EnsureCompleted();
   heap()->old_space()->RefillFreeList();
   heap()->code_space()->RefillFreeList();
   heap()->map_space()->RefillFreeList();
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap && !evacuation()) {
     VerifyEvacuation(heap_);
   }
 #endif
 }
 
 bool MarkCompactCollector::Sweeper::IsSweepingCompleted() {
-  if (!pending_sweeper_tasks_semaphore_.WaitFor(
-          base::TimeDelta::FromSeconds(0))) {
-    return false;
+  while (pending_sweeper_tasks_semaphore_.WaitFor(
+      base::TimeDelta::FromSeconds(0))) {
+    num_sweeping_tasks_.Increment(-1);
   }
-  pending_sweeper_tasks_semaphore_.Signal();
-  return true;
+  return num_sweeping_tasks_.Value() == 0;
 }
 
 void Marking::TransferMark(Heap* heap, Address old_start, Address new_start) {
   // This is only used when resizing an object.
   DCHECK(MemoryChunk::FromAddress(old_start) ==
          MemoryChunk::FromAddress(new_start));
 
   if (!heap->incremental_marking()->IsMarking() ||
       Page::FromAddress(old_start)->IsFlagSet(Page::BLACK_PAGE))
     return;
@@ skipping 3391 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8