[heap] Avoid the use of cells to point from code to new-space objects.

src/heap/heap.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/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 1453 matching lines @@
 
   isolate_->compilation_cache()->MarkCompactPrologue();
 
   CompletelyClearInstanceofCache();
 
   FlushNumberStringCache();
   ClearNormalizedMapCaches();
 }
 
 
-#ifdef VERIFY_HEAP
-// Visitor class to verify pointers in code or data space do not point into
-// new space.
-class VerifyNonPointerSpacePointersVisitor : public ObjectVisitor {
- public:
-  explicit VerifyNonPointerSpacePointersVisitor(Heap* heap) : heap_(heap) {}
-
-  void VisitPointers(Object** start, Object** end) override {
-    for (Object** current = start; current < end; current++) {
-      if ((*current)->IsHeapObject()) {
-        CHECK(!heap_->InNewSpace(HeapObject::cast(*current)));
-      }
-    }
-  }
-
- private:
-  Heap* heap_;
-};
-
-
-static void VerifyNonPointerSpacePointers(Heap* heap) {
-  // Verify that there are no pointers to new space in spaces where we
-  // do not expect them.
-  VerifyNonPointerSpacePointersVisitor v(heap);
-  HeapObjectIterator code_it(heap->code_space());
-  for (HeapObject* object = code_it.Next(); object != NULL;
-       object = code_it.Next())
-    object->Iterate(&v);
-}
-#endif  // VERIFY_HEAP
-
-
 void Heap::CheckNewSpaceExpansionCriteria() {
   if (FLAG_experimental_new_space_growth_heuristic) {
     if (new_space_.TotalCapacity() < new_space_.MaximumCapacity() &&
         survived_last_scavenge_ * 100 / new_space_.TotalCapacity() >= 10) {
       // Grow the size of new space if there is room to grow, and more than 10%
       // have survived the last scavenge.
       new_space_.Grow();
       survived_since_last_expansion_ = 0;
     }
   } else if (new_space_.TotalCapacity() < new_space_.MaximumCapacity() &&
@@ skipping 90 matching lines @@
   RelocationLock relocation_lock(this);
   // There are soft limits in the allocation code, designed to trigger a mark
   // sweep collection by failing allocations. There is no sense in trying to
   // trigger one during scavenge: scavenges allocation should always succeed.
   AlwaysAllocateScope scope(isolate());
 
   // Bump-pointer allocations done during scavenge are not real allocations.
   // Pause the inline allocation steps.
   PauseAllocationObserversScope pause_observers(this);
 
-#ifdef VERIFY_HEAP
-  if (FLAG_verify_heap) VerifyNonPointerSpacePointers(this);
-#endif
-
   gc_state_ = SCAVENGE;
 
   // Implements Cheney's copying algorithm
   LOG(isolate_, ResourceEvent("scavenge", "begin"));
 
   // Used for updating survived_since_last_expansion_ at function end.
   intptr_t survived_watermark = PromotedSpaceSizeOfObjects();
 
   scavenge_collector_->SelectScavengingVisitorsTable();
 
@@ skipping 1222 matching lines @@
     set_cleared_optimized_code_map(*cleared_optimized_code_map);
   }
 
   set_detached_contexts(empty_fixed_array());
   set_retained_maps(ArrayList::cast(empty_fixed_array()));
 
   set_weak_object_to_code_table(
       *WeakHashTable::New(isolate(), 16, USE_DEFAULT_MINIMUM_CAPACITY,
                           TENURED));
 
+  set_weak_new_space_object_to_code_list(
+      ArrayList::cast(*(factory->NewFixedArray(16, TENURED))));
+  weak_new_space_object_to_code_list()->SetLength(0);
+
   set_script_list(Smi::FromInt(0));
 
   Handle<SeededNumberDictionary> slow_element_dictionary =
       SeededNumberDictionary::New(isolate(), 0, TENURED);
   slow_element_dictionary->set_requires_slow_elements();
   set_empty_slow_element_dictionary(*slow_element_dictionary);
 
   set_materialized_objects(*factory->NewFixedArray(0, TENURED));
 
   // Handling of script id generation is in Heap::NextScriptId().
@@ skipping 36 matching lines @@
 
   // Initialize descriptor cache.
   isolate_->descriptor_lookup_cache()->Clear();
 
   // Initialize compilation cache.
   isolate_->compilation_cache()->Clear();
 
   CreateFixedStubs();
 }
 
-
 bool Heap::RootCanBeWrittenAfterInitialization(Heap::RootListIndex root_index) {
   switch (root_index) {
     case kNumberStringCacheRootIndex:
     case kInstanceofCacheFunctionRootIndex:
     case kInstanceofCacheMapRootIndex:
     case kInstanceofCacheAnswerRootIndex:
     case kCodeStubsRootIndex:
     case kEmptyScriptRootIndex:
     case kSymbolRegistryRootIndex:
     case kScriptListRootIndex:
     case kMaterializedObjectsRootIndex:
     case kMicrotaskQueueRootIndex:
     case kDetachedContextsRootIndex:
     case kWeakObjectToCodeTableRootIndex:
+    case kWeakNewSpaceObjectToCodeListRootIndex:
     case kRetainedMapsRootIndex:
     case kNoScriptSharedFunctionInfosRootIndex:
     case kWeakStackTraceListRootIndex:
 // Smi values
 #define SMI_ENTRY(type, name, Name) case k##Name##RootIndex:
       SMI_ROOT_LIST(SMI_ENTRY)
 #undef SMI_ENTRY
     // String table
     case kStringTableRootIndex:
       return true;
@@ skipping 2642 matching lines @@
   for (int i = 0; i < gc_epilogue_callbacks_.length(); ++i) {
     if (gc_epilogue_callbacks_[i].callback == callback) {
       gc_epilogue_callbacks_.Remove(i);
       return;
     }
   }
   UNREACHABLE();
 }
 
 // TODO(ishell): Find a better place for this.
+void Heap::AddWeakNewSpaceObjectToCodeDependency(Handle<HeapObject> obj,
+                                                 Handle<WeakCell> code) {
+  DCHECK(InNewSpace(*obj));
+  DCHECK(!InNewSpace(*code));
+  Handle<ArrayList> list(weak_new_space_object_to_code_list(), isolate());
+  list = ArrayList::Add(list, isolate()->factory()->NewWeakCell(obj), code);
+  if (*list != weak_new_space_object_to_code_list()) {
+    set_weak_new_space_object_to_code_list(*list);
+  }
+}
+
+// TODO(ishell): Find a better place for this.
 void Heap::AddWeakObjectToCodeDependency(Handle<HeapObject> obj,
                                          Handle<DependentCode> dep) {
   DCHECK(!InNewSpace(*obj));
   DCHECK(!InNewSpace(*dep));
   Handle<WeakHashTable> table(weak_object_to_code_table(), isolate());
   table = WeakHashTable::Put(table, obj, dep);
   if (*table != weak_object_to_code_table())
     set_weak_object_to_code_table(*table);
   DCHECK_EQ(*dep, LookupWeakObjectToCodeDependency(obj));
 }
@@ skipping 133 matching lines @@
 void Heap::ClearRecordedSlotRange(Address start, Address end) {
   Page* page = Page::FromAddress(start);
   if (!page->InNewSpace()) {
     store_buffer()->MoveEntriesToRememberedSet();
     DCHECK_EQ(page->owner()->identity(), OLD_SPACE);
     RememberedSet<OLD_TO_NEW>::RemoveRange(page, start, end);
     RememberedSet<OLD_TO_OLD>::RemoveRange(page, start, end);
   }
 }
 
+void Heap::RecordWriteIntoCodeSlow(Code* host, RelocInfo* rinfo,
+                                   Object* value) {
+  DCHECK(InNewSpace(value));
+  Page* source_page = Page::FromAddress(reinterpret_cast<Address>(host));
+  RelocInfo::Mode rmode = rinfo->rmode();
+  Address addr = rinfo->pc();
+  SlotType slot_type = SlotTypeForRelocInfoMode(rmode);
+  if (rinfo->IsInConstantPool()) {

[ulan, 2016/06/09 14:45:22]

Could you please extract this code into a function and share with mark compact?

[ahaas, 2016/06/10 11:00:34]

As discussed in person sharing this code and still inlining it is difficult
because RelocInfo::IsCodeTarget(rmode) requires to include inline headers.

+    addr = rinfo->constant_pool_entry_address();
+    if (RelocInfo::IsCodeTarget(rmode)) {
+      slot_type = CODE_ENTRY_SLOT;
+    } else {
+      DCHECK(RelocInfo::IsEmbeddedObject(rmode));
+      slot_type = OBJECT_SLOT;
+    }
+  }
+  RememberedSet<OLD_TO_NEW>::InsertTyped(
+      source_page, reinterpret_cast<Address>(host), slot_type, addr);
+}
+
 Space* AllSpaces::next() {
   switch (counter_++) {
     case NEW_SPACE:
       return heap_->new_space();
     case OLD_SPACE:
       return heap_->old_space();
     case CODE_SPACE:
       return heap_->code_space();
     case MAP_SPACE:
       return heap_->map_space();
@@ skipping 649 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8