[heap] Use HashMap as scratchpad backing store

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 1596 matching lines @@
 };
 
 
 class MarkCompactCollector::EvacuateNewSpaceVisitor final
     : public MarkCompactCollector::EvacuateVisitorBase {
  public:
   static const intptr_t kLabSize = 4 * KB;
   static const intptr_t kMaxLabObjectSize = 256;
 
   explicit EvacuateNewSpaceVisitor(Heap* heap,
-                                   SlotsBuffer** evacuation_slots_buffer)
+                                   SlotsBuffer** evacuation_slots_buffer,
+                                   HashMap* local_pretenuring_feedback)
       : EvacuateVisitorBase(heap, evacuation_slots_buffer),
         buffer_(LocalAllocationBuffer::InvalidBuffer()),
         space_to_allocate_(NEW_SPACE),
         promoted_size_(0),
-        semispace_copied_size_(0) {}
+        semispace_copied_size_(0),
+        local_pretenuring_feedback_(local_pretenuring_feedback) {}
 
   bool Visit(HeapObject* object) override {
-    Heap::UpdateAllocationSiteFeedback(object, Heap::RECORD_SCRATCHPAD_SLOT);
+    heap_->UpdateAllocationSite(object, local_pretenuring_feedback_);
     int size = object->Size();
     HeapObject* target_object = nullptr;
     if (heap_->ShouldBePromoted(object->address(), size) &&
         TryEvacuateObject(heap_->old_space(), object, &target_object)) {
       // If we end up needing more special cases, we should factor this out.
       if (V8_UNLIKELY(target_object->IsJSArrayBuffer())) {
         heap_->array_buffer_tracker()->Promote(
             JSArrayBuffer::cast(target_object));
       }
       promoted_size_ += size;
@@ skipping 106 matching lines @@
         }
       }
     }
     return allocation;
   }
 
   LocalAllocationBuffer buffer_;
   AllocationSpace space_to_allocate_;
   intptr_t promoted_size_;
   intptr_t semispace_copied_size_;
+  HashMap* local_pretenuring_feedback_;
 };
 
 
 class MarkCompactCollector::EvacuateOldSpaceVisitor final
     : public MarkCompactCollector::EvacuateVisitorBase {
  public:
   EvacuateOldSpaceVisitor(Heap* heap,
                           CompactionSpaceCollection* compaction_spaces,
                           SlotsBuffer** evacuation_slots_buffer)
       : EvacuateVisitorBase(heap, evacuation_slots_buffer),
@@ skipping 1317 matching lines @@
   // The target object has to be black.
   CHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
 
   // The target object is black but we don't know if the source slot is black.
   // The source object could have died and the slot could be part of a free
   // space. Use the mark bit iterator to find out about liveness of the slot.
   CHECK(IsSlotInBlackObjectSlow(Page::FromAddress(slot), slot));
 }
 
 
-void MarkCompactCollector::EvacuateNewSpace() {
+void MarkCompactCollector::EvacuateNewSpacePrologue() {
   // There are soft limits in the allocation code, designed trigger a mark
   // sweep collection by failing allocations.  But since we are already in
   // a mark-sweep allocation, there is no sense in trying to trigger one.
   AlwaysAllocateScope scope(isolate());
 
   NewSpace* new_space = heap()->new_space();
 
   // Store allocation range before flipping semispaces.
   Address from_bottom = new_space->bottom();
   Address from_top = new_space->top();
 
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.
   new_space->Flip();
   new_space->ResetAllocationInfo();
 
+  newspace_evacuation_candidates_.Clear();
+  NewSpacePageIterator it(from_bottom, from_top);
+  while (it.has_next()) {
+    newspace_evacuation_candidates_.Add(it.next());
+  }
+}
+
+
+HashMap* MarkCompactCollector::EvacuateNewSpaceInParallel() {
+  HashMap* local_pretenuring_feedback = new HashMap(
+      HashMap::PointersMatch, kInitialLocalPretenuringFeedbackCapacity);
+  EvacuateNewSpaceVisitor new_space_visitor(heap(), &migration_slots_buffer_,
+                                            local_pretenuring_feedback);
   // First pass: traverse all objects in inactive semispace, remove marks,
   // migrate live objects and write forwarding addresses.  This stage puts
   // new entries in the store buffer and may cause some pages to be marked
   // scan-on-scavenge.
-  NewSpacePageIterator it(from_bottom, from_top);
-  EvacuateNewSpaceVisitor new_space_visitor(heap(), &migration_slots_buffer_);
-  while (it.has_next()) {
-    NewSpacePage* p = it.next();
+  for (int i = 0; i < newspace_evacuation_candidates_.length(); i++) {
+    NewSpacePage* p =
+        reinterpret_cast<NewSpacePage*>(newspace_evacuation_candidates_[i]);
     bool ok = VisitLiveObjects(p, &new_space_visitor, kClearMarkbits);
     USE(ok);
     DCHECK(ok);
   }
   heap_->IncrementPromotedObjectsSize(
       static_cast<int>(new_space_visitor.promoted_size()));
   heap_->IncrementSemiSpaceCopiedObjectSize(
       static_cast<int>(new_space_visitor.semispace_copied_size()));
   heap_->IncrementYoungSurvivorsCounter(
       static_cast<int>(new_space_visitor.promoted_size()) +
       static_cast<int>(new_space_visitor.semispace_copied_size()));
-  new_space->set_age_mark(new_space->top());
+  return local_pretenuring_feedback;
 }
 
 
 void MarkCompactCollector::AddEvacuationSlotsBufferSynchronized(
     SlotsBuffer* evacuation_slots_buffer) {
   base::LockGuard<base::Mutex> lock_guard(&evacuation_slots_buffers_mutex_);
   evacuation_slots_buffers_.Add(evacuation_slots_buffer);
 }
 
 
@@ skipping 447 matching lines @@
       }
     }
   }
 }
 
 
 void MarkCompactCollector::EvacuateNewSpaceAndCandidates() {
   GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_EVACUATE);
   Heap::RelocationLock relocation_lock(heap());
 
+  HashMap* local_pretenuring_feedback = nullptr;
   {
     GCTracer::Scope gc_scope(heap()->tracer(),
                              GCTracer::Scope::MC_EVACUATE_NEW_SPACE);
     EvacuationScope evacuation_scope(this);
-    EvacuateNewSpace();
+    EvacuateNewSpacePrologue();
+    local_pretenuring_feedback = EvacuateNewSpaceInParallel();
+    heap_->new_space()->set_age_mark(heap_->new_space()->top());
   }
 
   {
     GCTracer::Scope gc_scope(heap()->tracer(),
                              GCTracer::Scope::MC_EVACUATE_CANDIDATES);
     EvacuationScope evacuation_scope(this);
     EvacuatePagesInParallel();
   }
 
+  {
+    heap_->MergeAllocationSitePretenuringFeedback(*local_pretenuring_feedback);
+    delete local_pretenuring_feedback;
+  }
+
   UpdatePointersAfterEvacuation();
 
   {
     GCTracer::Scope gc_scope(heap()->tracer(),
                              GCTracer::Scope::MC_EVACUATE_CLEAN_UP);
     // After updating all pointers, we can finally sweep the aborted pages,
     // effectively overriding any forward pointers.
     SweepAbortedPages();
 
     // EvacuateNewSpaceAndCandidates iterates over new space objects and for
@@ skipping 488 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(&rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8