Change RecordSlot interface. Make it more robust by replacing anchor slot with actual object.

BUG=

Review URL: https://codereview.chromium.org/1259613006

Cr-Commit-Position: refs/heads/master@{#30007}

src/heap/heap.cc

@@ -2084,15 +2084,17 @@ Address Heap::DoScavenge(ObjectVisitor* scavenge_visitor,
             int end_of_region_offset;
             if (helper.IsTagged(offset, size, &end_of_region_offset)) {
               IterateAndMarkPointersToFromSpace(
-                  record_slots, obj_address + offset,
-                  obj_address + end_of_region_offset, &ScavengeObject);
+                  target, obj_address + offset,
+                  obj_address + end_of_region_offset, record_slots,
+                  &ScavengeObject);
             }
             offset = end_of_region_offset;
           }
         } else {
 #endif
-          IterateAndMarkPointersToFromSpace(
-              record_slots, obj_address, obj_address + size, &ScavengeObject);
+          IterateAndMarkPointersToFromSpace(target, obj_address,
+                                            obj_address + size, record_slots,
+                                            &ScavengeObject);
 #if V8_DOUBLE_FIELDS_UNBOXING
         }
 #endif
@@ -2418,7 +2420,7 @@ class ScavengingVisitor : public StaticVisitorBase {
           target->address() + JSFunction::kCodeEntryOffset;
       Code* code = Code::cast(Code::GetObjectFromEntryAddress(code_entry_slot));
       map->GetHeap()->mark_compact_collector()->RecordCodeEntrySlot(
-          code_entry_slot, code);
+          target, code_entry_slot, code);
     }
   }
 
@@ -3582,8 +3584,8 @@ void Heap::AddAllocationSiteToScratchpad(AllocationSite* site,
       // candidates are not part of the global list of old space pages and
       // releasing an evacuation candidate due to a slots buffer overflow
       // results in lost pages.
-      mark_compact_collector()->RecordSlot(slot, slot, *slot,
-                                           SlotsBuffer::IGNORE_OVERFLOW);
+      mark_compact_collector()->RecordSlot(allocation_sites_scratchpad(), slot,
+                                           *slot, SlotsBuffer::IGNORE_OVERFLOW);
     }
     allocation_sites_scratchpad_length_++;
   }
@@ -5132,33 +5134,33 @@ void Heap::ZapFromSpace() {
 }
 
 
-void Heap::IterateAndMarkPointersToFromSpace(bool record_slots, Address start,
-                                             Address end,
+void Heap::IterateAndMarkPointersToFromSpace(HeapObject* object, Address start,
+                                             Address end, bool record_slots,
                                              ObjectSlotCallback callback) {
   Address slot_address = start;
 
   while (slot_address < end) {
     Object** slot = reinterpret_cast<Object**>(slot_address);
-    Object* object = *slot;
+    Object* target = *slot;
     // If the store buffer becomes overfull we mark pages as being exempt from
     // the store buffer.  These pages are scanned to find pointers that point
     // to the new space.  In that case we may hit newly promoted objects and
     // fix the pointers before the promotion queue gets to them.  Thus the 'if'.
-    if (object->IsHeapObject()) {
-      if (Heap::InFromSpace(object)) {
+    if (target->IsHeapObject()) {
+      if (Heap::InFromSpace(target)) {
         callback(reinterpret_cast<HeapObject**>(slot),
-                 HeapObject::cast(object));
-        Object* new_object = *slot;
-        if (InNewSpace(new_object)) {
-          SLOW_DCHECK(Heap::InToSpace(new_object));
-          SLOW_DCHECK(new_object->IsHeapObject());
+                 HeapObject::cast(target));
+        Object* new_target = *slot;
+        if (InNewSpace(new_target)) {
+          SLOW_DCHECK(Heap::InToSpace(new_target));
+          SLOW_DCHECK(new_target->IsHeapObject());
           store_buffer_.EnterDirectlyIntoStoreBuffer(
               reinterpret_cast<Address>(slot));
         }
-        SLOW_DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_object));
+        SLOW_DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_target));
       } else if (record_slots &&
-                 MarkCompactCollector::IsOnEvacuationCandidate(object)) {
-        mark_compact_collector()->RecordSlot(slot, slot, object);
+                 MarkCompactCollector::IsOnEvacuationCandidate(target)) {
+        mark_compact_collector()->RecordSlot(object, slot, target);
       }
     }
     slot_address += kPointerSize;

src/heap/heap.h

@@ -952,9 +952,9 @@ class Heap {
   void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
 
   // Iterate pointers to from semispace of new space found in memory interval
-  // from start to end.
-  void IterateAndMarkPointersToFromSpace(bool record_slots, Address start,
-                                         Address end,
+  // from start to end within |object|.
+  void IterateAndMarkPointersToFromSpace(HeapObject* object, Address start,
+                                         Address end, bool record_slots,
                                          ObjectSlotCallback callback);
 
   // Returns whether the object resides in new space.

src/heap/incremental-marking.cc

@@ -40,8 +40,7 @@ void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,
     MarkBit obj_bit = Marking::MarkBitFrom(obj);
     if (Marking::IsBlack(obj_bit)) {
       // Object is not going to be rescanned we need to record the slot.
-      heap_->mark_compact_collector()->RecordSlot(HeapObject::RawField(obj, 0),
-                                                  slot, value);
+      heap_->mark_compact_collector()->RecordSlot(obj, slot, value);
     }
   }
 }
@@ -92,7 +91,7 @@ void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host,
   if (BaseRecordWrite(host, slot, value)) {
     DCHECK(slot != NULL);
     heap_->mark_compact_collector()->RecordCodeEntrySlot(
-        reinterpret_cast<Address>(slot), value);
+        host, reinterpret_cast<Address>(slot), value);
   }
 }
 
@@ -177,8 +176,7 @@ class IncrementalMarkingMarkingVisitor
       int already_scanned_offset = start_offset;
       bool scan_until_end = false;
       do {
-        VisitPointersWithAnchor(heap, HeapObject::RawField(object, 0),
-                                HeapObject::RawField(object, start_offset),
+        VisitPointers(heap, object, HeapObject::RawField(object, start_offset),
                       HeapObject::RawField(object, end_offset));
         start_offset = end_offset;
         end_offset = Min(object_size, end_offset + kProgressBarScanningChunk);
@@ -214,31 +212,21 @@ class IncrementalMarkingMarkingVisitor
     VisitNativeContext(map, context);
   }
 
-  INLINE(static void VisitPointer(Heap* heap, Object** p)) {
-    Object* obj = *p;
-    if (obj->IsHeapObject()) {
-      heap->mark_compact_collector()->RecordSlot(p, p, obj);
-      MarkObject(heap, obj);
+  INLINE(static void VisitPointer(Heap* heap, HeapObject* object, Object** p)) {
+    Object* target = *p;
+    if (target->IsHeapObject()) {
+      heap->mark_compact_collector()->RecordSlot(object, p, target);
+      MarkObject(heap, target);
     }
   }
 
-  INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
-    for (Object** p = start; p < end; p++) {
-      Object* obj = *p;
-      if (obj->IsHeapObject()) {
-        heap->mark_compact_collector()->RecordSlot(start, p, obj);
-        MarkObject(heap, obj);
-      }
-    }
-  }
-
-  INLINE(static void VisitPointersWithAnchor(Heap* heap, Object** anchor,
+  INLINE(static void VisitPointers(Heap* heap, HeapObject* object,
                                    Object** start, Object** end)) {
     for (Object** p = start; p < end; p++) {
-      Object* obj = *p;
-      if (obj->IsHeapObject()) {
-        heap->mark_compact_collector()->RecordSlot(anchor, p, obj);
-        MarkObject(heap, obj);
+      Object* target = *p;
+      if (target->IsHeapObject()) {
+        heap->mark_compact_collector()->RecordSlot(object, p, target);
+        MarkObject(heap, target);
       }
     }
   }

src/heap/mark-compact-inl.h

@@ -55,15 +55,15 @@ bool MarkCompactCollector::IsMarked(Object* obj) {
 }
 
 
-void MarkCompactCollector::RecordSlot(Object** anchor_slot, Object** slot,
-                                      Object* object,
+void MarkCompactCollector::RecordSlot(HeapObject* object, Object** slot,
+                                      Object* target,
                                       SlotsBuffer::AdditionMode mode) {
-  Page* object_page = Page::FromAddress(reinterpret_cast<Address>(object));
-  if (object_page->IsEvacuationCandidate() &&
-      !ShouldSkipEvacuationSlotRecording(anchor_slot)) {
+  Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target));
+  if (target_page->IsEvacuationCandidate() &&
+      !ShouldSkipEvacuationSlotRecording(object)) {
     if (!SlotsBuffer::AddTo(&slots_buffer_allocator_,
-                            object_page->slots_buffer_address(), slot, mode)) {
-      EvictPopularEvacuationCandidate(object_page);
+                            target_page->slots_buffer_address(), slot, mode)) {
+      EvictPopularEvacuationCandidate(target_page);
     }
   }
 }

src/heap/mark-compact.h

@@ -640,11 +640,6 @@ class MarkCompactCollector {
   void VerifyOmittedMapChecks();
 #endif
 
-  INLINE(static bool ShouldSkipEvacuationSlotRecording(Object** anchor)) {
-    return Page::FromAddress(reinterpret_cast<Address>(anchor))
-        ->ShouldSkipEvacuationSlotRecording();
-  }
-
   INLINE(static bool ShouldSkipEvacuationSlotRecording(Object* host)) {
     return Page::FromAddress(reinterpret_cast<Address>(host))
         ->ShouldSkipEvacuationSlotRecording();
@@ -656,11 +651,11 @@ class MarkCompactCollector {
   }
 
   void RecordRelocSlot(RelocInfo* rinfo, Object* target);
-  void RecordCodeEntrySlot(Address slot, Code* target);
+  void RecordCodeEntrySlot(HeapObject* object, Address slot, Code* target);
   void RecordCodeTargetPatch(Address pc, Code* target);
 
   INLINE(void RecordSlot(
-      Object** anchor_slot, Object** slot, Object* object,
+      HeapObject* object, Object** slot, Object* target,
       SlotsBuffer::AdditionMode mode = SlotsBuffer::FAIL_ON_OVERFLOW));
 
   void MigrateObject(HeapObject* dst, HeapObject* src, int size,

src/heap/objects-visiting.cc

@@ -216,7 +216,7 @@ Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer) {
         if (record_slots) {
           Object** next_slot =
               HeapObject::RawField(tail, WeakListVisitor<T>::WeakNextOffset());
-          collector->RecordSlot(next_slot, next_slot, retained);
+          collector->RecordSlot(tail, next_slot, retained);
         }
       }
       // Retained object is new tail.
@@ -327,8 +327,7 @@ struct WeakListVisitor<Context> {
       // Record the updated slot if necessary.
       Object** head_slot =
           HeapObject::RawField(context, FixedArray::SizeFor(index));
-      heap->mark_compact_collector()->RecordSlot(head_slot, head_slot,
-                                                 list_head);
+      heap->mark_compact_collector()->RecordSlot(context, head_slot, list_head);
     }
   }
 

src/heap/objects-visiting.h

@@ -215,7 +215,7 @@ class BodyVisitorBase : public AllStatic {
  private:
   INLINE(static void IterateRawPointers(Heap* heap, HeapObject* object,
                                         int start_offset, int end_offset)) {
-    StaticVisitor::VisitPointers(heap,
+    StaticVisitor::VisitPointers(heap, object,
                                  HeapObject::RawField(object, start_offset),
                                  HeapObject::RawField(object, end_offset));
   }
@@ -297,22 +297,23 @@ class StaticNewSpaceVisitor : public StaticVisitorBase {
     return table_.GetVisitor(map)(map, obj);
   }
 
-  INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
+  INLINE(static void VisitPointers(Heap* heap, HeapObject* object,
+                                   Object** start, Object** end)) {
     for (Object** p = start; p < end; p++) StaticVisitor::VisitPointer(heap, p);
   }
 
  private:
   INLINE(static int VisitJSFunction(Map* map, HeapObject* object)) {
     Heap* heap = map->GetHeap();
-    VisitPointers(heap,
+    VisitPointers(heap, object,
                   HeapObject::RawField(object, JSFunction::kPropertiesOffset),
                   HeapObject::RawField(object, JSFunction::kCodeEntryOffset));
 
     // Don't visit code entry. We are using this visitor only during scavenges.
 
     VisitPointers(
-        heap, HeapObject::RawField(object,
-                                   JSFunction::kCodeEntryOffset + kPointerSize),
+        heap, object, HeapObject::RawField(
+                          object, JSFunction::kCodeEntryOffset + kPointerSize),
         HeapObject::RawField(object, JSFunction::kNonWeakFieldsEndOffset));
     return JSFunction::kSize;
   }
@@ -410,7 +411,8 @@ class StaticMarkingVisitor : public StaticVisitorBase {
 
   INLINE(static void VisitPropertyCell(Map* map, HeapObject* object));
   INLINE(static void VisitWeakCell(Map* map, HeapObject* object));
-  INLINE(static void VisitCodeEntry(Heap* heap, Address entry_address));
+  INLINE(static void VisitCodeEntry(Heap* heap, HeapObject* object,
+                                    Address entry_address));
   INLINE(static void VisitEmbeddedPointer(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitCell(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitDebugTarget(Heap* heap, RelocInfo* rinfo));