Version 3.10.3

src/heap.cc

Index: src/heap.cc
===================================================================
--- src/heap.cc	(revision 11348)
+++ src/heap.cc	(working copy)
@@ -1124,6 +1124,27 @@
 }
 
 
+class ScavengeWeakObjectRetainer : public WeakObjectRetainer {
+ public:
+  explicit ScavengeWeakObjectRetainer(Heap* heap) : heap_(heap) { }
+
+  virtual Object* RetainAs(Object* object) {
+    if (!heap_->InFromSpace(object)) {
+      return object;
+    }
+
+    MapWord map_word = HeapObject::cast(object)->map_word();
+    if (map_word.IsForwardingAddress()) {
+      return map_word.ToForwardingAddress();
+    }
+    return NULL;
+  }
+
+ private:
+  Heap* heap_;
+};
+
+
 void Heap::Scavenge() {
 #ifdef DEBUG
   if (FLAG_verify_heap) VerifyNonPointerSpacePointers();
@@ -1222,6 +1243,9 @@
   }
   incremental_marking()->UpdateMarkingDequeAfterScavenge();
 
+  ScavengeWeakObjectRetainer weak_object_retainer(this);
+  ProcessWeakReferences(&weak_object_retainer);
+
   ASSERT(new_space_front == new_space_.top());
 
   // Set age mark.
@@ -1308,7 +1332,8 @@
 
 static Object* ProcessFunctionWeakReferences(Heap* heap,
                                              Object* function,
-                                             WeakObjectRetainer* retainer) {
+                                             WeakObjectRetainer* retainer,
+                                             bool record_slots) {
   Object* undefined = heap->undefined_value();
   Object* head = undefined;
   JSFunction* tail = NULL;
@@ -1325,6 +1350,12 @@
         // Subsequent elements in the list.
         ASSERT(tail != NULL);
         tail->set_next_function_link(retain);
+        if (record_slots) {
+          Object** next_function =
+              HeapObject::RawField(tail, JSFunction::kNextFunctionLinkOffset);
+          heap->mark_compact_collector()->RecordSlot(
+              next_function, next_function, retain);
+        }
       }
       // Retained function is new tail.
       candidate_function = reinterpret_cast<JSFunction*>(retain);
@@ -1353,6 +1384,15 @@
   Object* head = undefined;
   Context* tail = NULL;
   Object* candidate = global_contexts_list_;
+
+  // We don't record weak slots during marking or scavenges.
+  // Instead we do it once when we complete mark-compact cycle.
+  // Note that write barrier has no effect if we are already in the middle of
+  // compacting mark-sweep cycle and we have to record slots manually.
+  bool record_slots =
+      gc_state() == MARK_COMPACT &&
+      mark_compact_collector()->is_compacting();
+
   while (candidate != undefined) {
     // Check whether to keep the candidate in the list.
     Context* candidate_context = reinterpret_cast<Context*>(candidate);
@@ -1368,6 +1408,14 @@
                             Context::NEXT_CONTEXT_LINK,
                             retain,
                             UPDATE_WRITE_BARRIER);
+
+        if (record_slots) {
+          Object** next_context =
+              HeapObject::RawField(
+                  tail, FixedArray::SizeFor(Context::NEXT_CONTEXT_LINK));
+          mark_compact_collector()->RecordSlot(
+              next_context, next_context, retain);
+        }
       }
       // Retained context is new tail.
       candidate_context = reinterpret_cast<Context*>(retain);
@@ -1380,11 +1428,19 @@
           ProcessFunctionWeakReferences(
               this,
               candidate_context->get(Context::OPTIMIZED_FUNCTIONS_LIST),
-              retainer);
+              retainer,
+              record_slots);
       candidate_context->set_unchecked(this,
                                        Context::OPTIMIZED_FUNCTIONS_LIST,
                                        function_list_head,
                                        UPDATE_WRITE_BARRIER);
+      if (record_slots) {
+        Object** optimized_functions =
+            HeapObject::RawField(
+                tail, FixedArray::SizeFor(Context::OPTIMIZED_FUNCTIONS_LIST));
+        mark_compact_collector()->RecordSlot(
+            optimized_functions, optimized_functions, function_list_head);
+      }
     }
 
     // Move to next element in the list.
@@ -1484,6 +1540,27 @@
 }
 
 
+STATIC_ASSERT((FixedDoubleArray::kHeaderSize & kDoubleAlignmentMask) == 0);
+
+
+INLINE(static HeapObject* EnsureDoubleAligned(Heap* heap,
+                                              HeapObject* object,
+                                              int size));
+
+static HeapObject* EnsureDoubleAligned(Heap* heap,
+                                       HeapObject* object,
+                                       int size) {
+  if ((OffsetFrom(object->address()) & kDoubleAlignmentMask) != 0) {
+    heap->CreateFillerObjectAt(object->address(), kPointerSize);
+    return HeapObject::FromAddress(object->address() + kPointerSize);
+  } else {
+    heap->CreateFillerObjectAt(object->address() + size - kPointerSize,
+                               kPointerSize);
+    return object;
+  }
+}
+
+
 enum LoggingAndProfiling {
   LOGGING_AND_PROFILING_ENABLED,
   LOGGING_AND_PROFILING_DISABLED
@@ -1607,7 +1684,10 @@
     }
   }
 
-  template<ObjectContents object_contents, SizeRestriction size_restriction>
+
+  template<ObjectContents object_contents,
+           SizeRestriction size_restriction,
+           int alignment>
   static inline void EvacuateObject(Map* map,
                                     HeapObject** slot,
                                     HeapObject* object,
@@ -1616,19 +1696,26 @@
                 (object_size <= Page::kMaxNonCodeHeapObjectSize));
     SLOW_ASSERT(object->Size() == object_size);
 
+    int allocation_size = object_size;
+    if (alignment != kObjectAlignment) {
+      ASSERT(alignment == kDoubleAlignment);
+      allocation_size += kPointerSize;
+    }
+
     Heap* heap = map->GetHeap();
     if (heap->ShouldBePromoted(object->address(), object_size)) {
       MaybeObject* maybe_result;
 
       if ((size_restriction != SMALL) &&
-          (object_size > Page::kMaxNonCodeHeapObjectSize)) {
-        maybe_result = heap->lo_space()->AllocateRaw(object_size,
+          (allocation_size > Page::kMaxNonCodeHeapObjectSize)) {
+        maybe_result = heap->lo_space()->AllocateRaw(allocation_size,
                                                      NOT_EXECUTABLE);
       } else {
         if (object_contents == DATA_OBJECT) {
-          maybe_result = heap->old_data_space()->AllocateRaw(object_size);
+          maybe_result = heap->old_data_space()->AllocateRaw(allocation_size);
         } else {
-          maybe_result = heap->old_pointer_space()->AllocateRaw(object_size);
+          maybe_result =
+              heap->old_pointer_space()->AllocateRaw(allocation_size);
         }
       }
 
@@ -1636,6 +1723,10 @@
       if (maybe_result->ToObject(&result)) {
         HeapObject* target = HeapObject::cast(result);
 
+        if (alignment != kObjectAlignment) {
+          target = EnsureDoubleAligned(heap, target, allocation_size);
+        }
+
         // Order is important: slot might be inside of the target if target
         // was allocated over a dead object and slot comes from the store
         // buffer.
@@ -1643,18 +1734,27 @@
         MigrateObject(heap, object, target, object_size);
 
         if (object_contents == POINTER_OBJECT) {
-          heap->promotion_queue()->insert(target, object_size);
+          if (map->instance_type() == JS_FUNCTION_TYPE) {
+            heap->promotion_queue()->insert(
+                target, JSFunction::kNonWeakFieldsEndOffset);
+          } else {
+            heap->promotion_queue()->insert(target, object_size);
+          }
         }
 
         heap->tracer()->increment_promoted_objects_size(object_size);
         return;
       }
     }
-    MaybeObject* allocation = heap->new_space()->AllocateRaw(object_size);
+    MaybeObject* allocation = heap->new_space()->AllocateRaw(allocation_size);
     heap->promotion_queue()->SetNewLimit(heap->new_space()->top());
     Object* result = allocation->ToObjectUnchecked();
     HeapObject* target = HeapObject::cast(result);
 
+    if (alignment != kObjectAlignment) {
+      target = EnsureDoubleAligned(heap, target, allocation_size);
+    }
+
     // Order is important: slot might be inside of the target if target
     // was allocated over a dead object and slot comes from the store
     // buffer.
@@ -1690,7 +1790,7 @@
                                         HeapObject** slot,
                                         HeapObject* object) {
     int object_size = FixedArray::BodyDescriptor::SizeOf(map, object);
-    EvacuateObject<POINTER_OBJECT, UNKNOWN_SIZE>(map,
+    EvacuateObject<POINTER_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(map,
                                                  slot,
                                                  object,
                                                  object_size);
@@ -1702,10 +1802,11 @@
                                               HeapObject* object) {
     int length = reinterpret_cast<FixedDoubleArray*>(object)->length();
     int object_size = FixedDoubleArray::SizeFor(length);
-    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map,
-                                              slot,
-                                              object,
-                                              object_size);
+    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kDoubleAlignment>(
+        map,
+        slot,
+        object,
+        object_size);
   }
 
 
@@ -1713,7 +1814,8 @@
                                        HeapObject** slot,
                                        HeapObject* object) {
     int object_size = reinterpret_cast<ByteArray*>(object)->ByteArraySize();
-    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object, object_size);
+    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+        map, slot, object, object_size);
   }
 
 
@@ -1722,7 +1824,8 @@
                                             HeapObject* object) {
     int object_size = SeqAsciiString::cast(object)->
         SeqAsciiStringSize(map->instance_type());
-    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object, object_size);
+    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+        map, slot, object, object_size);
   }
 
 
@@ -1731,7 +1834,8 @@
                                               HeapObject* object) {
     int object_size = SeqTwoByteString::cast(object)->
         SeqTwoByteStringSize(map->instance_type());
-    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object, object_size);
+    EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+        map, slot, object, object_size);
   }
 
 
@@ -1774,7 +1878,8 @@
     }
 
     int object_size = ConsString::kSize;
-    EvacuateObject<POINTER_OBJECT, SMALL>(map, slot, object, object_size);
+    EvacuateObject<POINTER_OBJECT, SMALL, kObjectAlignment>(
+        map, slot, object, object_size);
   }
 
   template<ObjectContents object_contents>
@@ -1784,14 +1889,16 @@
     static inline void VisitSpecialized(Map* map,
                                         HeapObject** slot,
                                         HeapObject* object) {
-      EvacuateObject<object_contents, SMALL>(map, slot, object, object_size);
+      EvacuateObject<object_contents, SMALL, kObjectAlignment>(
+          map, slot, object, object_size);
     }
 
     static inline void Visit(Map* map,
                              HeapObject** slot,
                              HeapObject* object) {
       int object_size = map->instance_size();
-      EvacuateObject<object_contents, SMALL>(map, slot, object, object_size);
+      EvacuateObject<object_contents, SMALL, kObjectAlignment>(
+          map, slot, object, object_size);
     }
   };
 
@@ -3827,6 +3934,16 @@
 }
 
 
+MaybeObject* Heap::AllocateJSModule() {
+  // Allocate a fresh map. Modules do not have a prototype.
+  Map* map;
+  MaybeObject* maybe_map = AllocateMap(JS_MODULE_TYPE, JSModule::kSize);
+  if (!maybe_map->To(&map)) return maybe_map;
+  // Allocate the object based on the map.
+  return AllocateJSObjectFromMap(map, TENURED);
+}
+
+
 MaybeObject* Heap::AllocateJSArrayAndStorage(
     ElementsKind elements_kind,
     int length,
@@ -3963,7 +4080,7 @@
   // Fill these accessors into the dictionary.
   DescriptorArray* descs = map->instance_descriptors();
   for (int i = 0; i < descs->number_of_descriptors(); i++) {
-    PropertyDetails details(descs->GetDetails(i));
+    PropertyDetails details = descs->GetDetails(i);
     ASSERT(details.type() == CALLBACKS);  // Only accessors are expected.
     PropertyDetails d =
         PropertyDetails(details.attributes(), CALLBACKS, details.index());
@@ -4656,6 +4773,11 @@
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
   int size = FixedDoubleArray::SizeFor(length);
+
+#ifndef V8_HOST_ARCH_64_BIT
+  size += kPointerSize;
+#endif
+
   if (space == NEW_SPACE && size > kMaxObjectSizeInNewSpace) {
     // Too big for new space.
     space = LO_SPACE;
@@ -4668,7 +4790,12 @@
   AllocationSpace retry_space =
       (size <= Page::kMaxNonCodeHeapObjectSize) ? OLD_DATA_SPACE : LO_SPACE;
 
-  return AllocateRaw(size, space, retry_space);
+  HeapObject* object;
+  { MaybeObject* maybe_object = AllocateRaw(size, space, retry_space);
+    if (!maybe_object->To<HeapObject>(&object)) return maybe_object;
+  }
+
+  return EnsureDoubleAligned(this, object, size);
 }
 
 
@@ -4701,6 +4828,22 @@
 }
 
 
+MaybeObject* Heap::AllocateModuleContext(Context* previous,
+                                         ScopeInfo* scope_info) {
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateFixedArrayWithHoles(scope_info->ContextLength(), TENURED);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
+  Context* context = reinterpret_cast<Context*>(result);
+  context->set_map_no_write_barrier(module_context_map());
+  context->set_previous(previous);
+  context->set_extension(scope_info);
+  context->set_global(previous->global());
+  return context;
+}
+
+
 MaybeObject* Heap::AllocateFunctionContext(int length, JSFunction* function) {
   ASSERT(length >= Context::MIN_CONTEXT_SLOTS);
   Object* result;