Move SetFastElementsCapacity into GrowCapacityAndConvert

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index f2d617b8298e93d45d9dfb580f8549a7bfbfb0fa..e07fc8b76e620d6011b46f28b8bdd9337849c8a0 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11802,89 +11802,6 @@ void Code::Disassemble(const char* name, std::ostream& os) {  // NOLINT
 #endif  // ENABLE_DISASSEMBLER
 
 
-Handle<FixedArray> JSObject::SetFastElementsCapacity(
-    Handle<JSObject> object, int capacity,
-    SetFastElementsCapacitySmiMode smi_mode) {
-  // We should never end in here with a pixel or external array.
-  DCHECK(!object->HasExternalArrayElements());
-
-  // Allocate a new fast elements backing store.
-  Isolate* isolate = object->GetIsolate();
-  Handle<FixedArray> new_elements =
-      isolate->factory()->NewUninitializedFixedArray(capacity);
-
-  isolate->UpdateArrayProtectorOnSetLength(object);
-
-  ElementsKind elements_kind = object->GetElementsKind();
-  ElementsKind new_elements_kind;
-  // The resized array has FAST_*_SMI_ELEMENTS if the capacity mode forces it,
-  // or if it's allowed and the old elements array contained only SMIs.
-  bool has_fast_smi_elements =
-      (smi_mode == kForceSmiElements) ||
-      ((smi_mode == kAllowSmiElements) && object->HasFastSmiElements());
-  if (has_fast_smi_elements) {
-    if (IsHoleyElementsKind(elements_kind)) {
-      new_elements_kind = FAST_HOLEY_SMI_ELEMENTS;
-    } else {
-      new_elements_kind = FAST_SMI_ELEMENTS;
-    }
-  } else {
-    if (IsHoleyElementsKind(elements_kind)) {
-      new_elements_kind = FAST_HOLEY_ELEMENTS;
-    } else {
-      new_elements_kind = FAST_ELEMENTS;
-    }
-  }
-  Handle<FixedArrayBase> old_elements(object->elements());
-  ElementsAccessor* accessor = ElementsAccessor::ForKind(new_elements_kind);
-  accessor->CopyElements(object, new_elements, elements_kind);
-
-  if (elements_kind == SLOPPY_ARGUMENTS_ELEMENTS) {
-    Handle<FixedArray> parameter_map = Handle<FixedArray>::cast(old_elements);
-    parameter_map->set(1, *new_elements);
-  } else {
-    Handle<Map> new_map = (new_elements_kind != elements_kind)
-        ? GetElementsTransitionMap(object, new_elements_kind)
-        : handle(object->map());
-    JSObject::ValidateElements(object);
-    JSObject::SetMapAndElements(object, new_map, new_elements);
-
-    // Transition through the allocation site as well if present.
-    JSObject::UpdateAllocationSite(object, new_elements_kind);
-  }
-
-  if (FLAG_trace_elements_transitions) {
-    PrintElementsTransition(stdout, object, elements_kind, old_elements,
-                            object->GetElementsKind(), new_elements);
-  }
-
-  return new_elements;
-}
-
-
-Handle<FixedArray> JSObject::SetFastElementsCapacityAndLength(
-    Handle<JSObject> object, int capacity, int length,
-    SetFastElementsCapacitySmiMode smi_mode) {
-  Handle<FixedArray> new_elements =
-      SetFastElementsCapacity(object, capacity, smi_mode);
-  if (object->IsJSArray()) {
-    Handle<JSArray>::cast(object)->set_length(Smi::FromInt(length));
-  }
-  return new_elements;
-}
-
-
-void JSObject::SetFastDoubleElementsCapacityAndLength(Handle<JSObject> object,
-                                                      int capacity,
-                                                      int length) {
-  ElementsAccessor* accessor = ElementsAccessor::ForKind(FAST_DOUBLE_ELEMENTS);
-  accessor->GrowCapacityAndConvert(object, capacity);
-  if (object->IsJSArray()) {
-    Handle<JSArray>::cast(object)->set_length(Smi::FromInt(length));
-  }
-}
-
-
 // static
 void JSArray::Initialize(Handle<JSArray> array, int capacity, int length) {
   DCHECK(capacity >= 0);
@@ -12438,28 +12355,20 @@ void JSObject::AddFastElement(Handle<JSObject> object, uint32_t index,
   DCHECK(object->HasFastSmiOrObjectElements() ||
          object->HasFastArgumentsElements());
 
-  Isolate* isolate = object->GetIsolate();
-
   Handle<FixedArray> backing_store(FixedArray::cast(object->elements()));
   if (object->HasSloppyArgumentsElements()) {
     backing_store = handle(FixedArray::cast(backing_store->get(1)));
   } else {
-    // Array optimizations rely on the prototype lookups of Array objects always
-    // returning undefined. If there is a store to the initial prototype object,
-    // make sure all of these optimizations are invalidated.
-    isolate->UpdateArrayProtectorOnSetElement(object);
     backing_store = EnsureWritableFastElements(object);
   }
   uint32_t capacity = static_cast<uint32_t>(backing_store->length());
 
-  uint32_t new_capacity = capacity;
   // Check if the length property of this object needs to be updated.
   uint32_t array_length = 0;
   bool must_update_array_length = false;
   bool introduces_holes = true;
   if (object->IsJSArray()) {
-    CHECK(
-        Handle<JSArray>::cast(object)->length()->ToArrayLength(&array_length));
+    CHECK(JSArray::cast(*object)->length()->ToArrayLength(&array_length));
     introduces_holes = index > array_length;
     if (index >= array_length) {
       must_update_array_length = true;
@@ -12469,24 +12378,15 @@ void JSObject::AddFastElement(Handle<JSObject> object, uint32_t index,
     introduces_holes = index >= capacity;
   }
 
-  // If the array is growing, and it's not growth by a single element at the
-  // end, make sure that the ElementsKind is HOLEY.
-  if (introduces_holes && !IsFastHoleyElementsKind(object->GetElementsKind())) {
-    ElementsKind transitioned_kind =
-        GetHoleyElementsKind(object->GetElementsKind());
-    TransitionElementsKind(object, transitioned_kind);
-  }
-
+  uint32_t new_capacity = capacity;
   // Check if the capacity of the backing store needs to be increased, or if
   // a transition to slow elements is necessary.
   if (index >= capacity) {
     bool convert_to_slow = true;
     if ((index - capacity) < kMaxGap) {
       new_capacity = NewElementsCapacity(index + 1);
-      DCHECK(new_capacity > index);
-      if (!object->ShouldConvertToSlowElements(new_capacity)) {
-        convert_to_slow = false;
-      }
+      DCHECK_LT(index, new_capacity);
+      convert_to_slow = object->ShouldConvertToSlowElements(new_capacity);
     }
     if (convert_to_slow) {
       NormalizeElements(object);
@@ -12498,50 +12398,52 @@ void JSObject::AddFastElement(Handle<JSObject> object, uint32_t index,
   if (object->HasFastSmiElements() && !value->IsSmi()) {
     // Convert to fast double elements if appropriate.
     if (value->IsNumber()) {
-      // Consider fixing the boilerplate as well if we have one.
-      ElementsKind to_kind = IsHoleyElementsKind(object->GetElementsKind())
-                                 ? FAST_HOLEY_DOUBLE_ELEMENTS
-                                 : FAST_DOUBLE_ELEMENTS;
-
-      UpdateAllocationSite(object, to_kind);
-
-      SetFastDoubleElementsCapacityAndLength(object, new_capacity,
-                                             array_length);
-      FixedDoubleArray::cast(object->elements())->set(index, value->Number());
-      JSObject::ValidateElements(object);
+      ElementsKind to_kind =
+          introduces_holes ? FAST_HOLEY_DOUBLE_ELEMENTS : FAST_DOUBLE_ELEMENTS;
+      ElementsAccessor* accessor = ElementsAccessor::ForKind(to_kind);
+      accessor->GrowCapacityAndConvert(object, new_capacity);
+      AddFastDoubleElement(object, index, value);
       return;
     }
 
     // Change elements kind from Smi-only to generic FAST if necessary.
-    ElementsKind kind = object->HasFastHoleyElements()
-        ? FAST_HOLEY_ELEMENTS
-        : FAST_ELEMENTS;
+    ElementsKind kind = introduces_holes || object->HasFastHoleyElements()
+                            ? FAST_HOLEY_ELEMENTS
+                            : FAST_ELEMENTS;
 
     UpdateAllocationSite(object, kind);
     Handle<Map> new_map = GetElementsTransitionMap(object, kind);
     JSObject::MigrateToMap(object, new_map);
     DCHECK(IsFastObjectElementsKind(object->GetElementsKind()));
+  } else if (introduces_holes && !object->HasFastHoleyElements()) {
+    // If the array is growing, and it's not growth by a single element at the
+    // end, make sure that the ElementsKind is HOLEY.
+    ElementsKind transitioned_kind =
+        GetHoleyElementsKind(object->GetElementsKind());
+    TransitionElementsKind(object, transitioned_kind);
   }
 
   // Increase backing store capacity if that's been decided previously.
-  // Otherwise, set the new element and length.
-  if (new_capacity == capacity) {
-    DCHECK(object->elements()->IsFixedArray());
-    backing_store->set(index, *value);
-    if (must_update_array_length) {
-      Handle<JSArray>::cast(object)->set_length(Smi::FromInt(array_length));
-    }
-  } else {
-    SetFastElementsCapacitySmiMode smi_mode =
-        value->IsSmi() && object->HasFastSmiElements()
-            ? kAllowSmiElements
-            : kDontAllowSmiElements;
-    Handle<FixedArray> new_elements =
-        SetFastElementsCapacityAndLength(object, new_capacity, array_length,
-                                         smi_mode);
-    new_elements->set(index, *value);
-    JSObject::ValidateElements(object);
+  if (capacity != new_capacity) {
+    DCHECK(!(value->IsSmi() && object->HasFastDoubleElements()));

[Jakob Kummerow, 2015/06/22 17:03:02]

AFAICS you can DCHECK(!object->HasFastDoubleElements()) here.

[Toon Verwaest, 2015/06/22 18:31:01]

Done.

+    ElementsAccessor* accessor =
+        value->IsSmi() || object->HasSloppyArgumentsElements()
+            ? object->GetElementsAccessor()
+            : ElementsAccessor::ForKind(FAST_ELEMENTS);
+    accessor->GrowCapacityAndConvert(object, new_capacity);
   }
+
+  if (must_update_array_length) {
+    Handle<JSArray>::cast(object)->set_length(Smi::FromInt(array_length));
+  }
+
+  FixedArray* elements = FixedArray::cast(object->elements());
+  if (object->HasSloppyArgumentsElements()) {
+    elements = FixedArray::cast(elements->get(1));
+  }
+  elements->set(index, *value);
+
+  JSObject::ValidateElements(object);
 }
 
 
@@ -12701,18 +12603,9 @@ void JSObject::AddDictionaryElement(Handle<JSObject> object, uint32_t index,
     } else {
       new_length = dictionary->max_number_key() + 1;
     }
-    bool has_smi_only_elements = false;
-    bool should_convert_to_fast_double_elements =
-        object->ShouldConvertToFastDoubleElements(&has_smi_only_elements);
-    SetFastElementsCapacitySmiMode smi_mode =
-        has_smi_only_elements ? kForceSmiElements : kAllowSmiElements;
-
-    if (should_convert_to_fast_double_elements) {
-      SetFastDoubleElementsCapacityAndLength(object, new_length, new_length);
-    } else {
-      SetFastElementsCapacityAndLength(object, new_length, new_length,
-                                       smi_mode);
-    }
+    ElementsKind to_kind = object->BestFittingFastElementsKind();
+    ElementsAccessor* accessor = ElementsAccessor::ForKind(to_kind);
+    accessor->GrowCapacityAndConvert(object, new_length);
     JSObject::ValidateElements(object);
 #ifdef DEBUG
     if (FLAG_trace_normalization) {
@@ -12730,72 +12623,71 @@ void JSObject::AddFastDoubleElement(Handle<JSObject> object, uint32_t index,
   DCHECK(object->HasFastDoubleElements());
 
   Handle<FixedArrayBase> base_elms(FixedArrayBase::cast(object->elements()));
-  uint32_t elms_length = static_cast<uint32_t>(base_elms->length());
-  uint32_t length = elms_length;
+  uint32_t capacity = static_cast<uint32_t>(base_elms->length());
 
+  // Check if the length property of this object needs to be updated.
+  uint32_t array_length = 0;
+  bool must_update_array_length = false;
   bool introduces_holes = true;
   if (object->IsJSArray()) {
     // In case of JSArray, the length does not equal the capacity.
-    CHECK(Handle<JSArray>::cast(object)->length()->ToArrayLength(&length));
-    introduces_holes = index > length;
+    CHECK(JSArray::cast(*object)->length()->ToArrayLength(&array_length));
+    introduces_holes = index > array_length;
+    if (index >= array_length) {
+      must_update_array_length = true;
+      array_length = index + 1;
+    }
   } else {
-    introduces_holes = index >= elms_length;
+    introduces_holes = index >= capacity;
+  }
+
+  uint32_t new_capacity = capacity;
+  // Check if the capacity of the backing store needs to be increased, or if
+  // a transition to slow elements is necessary.
+  if (index >= capacity) {
+    bool convert_to_slow = true;
+    if ((index - capacity) < kMaxGap) {
+      new_capacity = NewElementsCapacity(index + 1);
+      DCHECK_LT(index, new_capacity);
+      convert_to_slow = object->ShouldConvertToSlowElements(new_capacity);
+    }
+    if (convert_to_slow) {
+      NormalizeElements(object);
+      AddDictionaryElement(object, index, value, NONE);
+      return;
+    }
   }
 
   // If the value object is not a heap number, switch to fast elements and try
   // again.
   if (!value->IsNumber()) {
-    SetFastElementsCapacityAndLength(object, elms_length, length,
-                                     kDontAllowSmiElements);
-    AddFastElement(object, index, value);
-    return;
+    ElementsKind to_kind =
+        introduces_holes ? FAST_HOLEY_ELEMENTS : FAST_ELEMENTS;
+    ElementsAccessor* accessor = ElementsAccessor::ForKind(to_kind);
+    accessor->GrowCapacityAndConvert(object, new_capacity);
+    return AddFastElement(object, index, value);
   }
 
   // If the array is growing, and it's not growth by a single element at the
   // end, make sure that the ElementsKind is HOLEY.
-  if (introduces_holes && !IsFastHoleyElementsKind(object->GetElementsKind())) {
-    ElementsKind transitioned_kind = FAST_HOLEY_DOUBLE_ELEMENTS;
+  if (introduces_holes && object->HasFastHoleyElements()) {

[Jakob Kummerow, 2015/06/22 17:03:02]

I think you want to keep the '!'.

[Toon Verwaest, 2015/06/22 18:31:01]

Done.

+    ElementsKind transitioned_kind =
+        GetHoleyElementsKind(object->GetElementsKind());
     TransitionElementsKind(object, transitioned_kind);
   }
 
-  // Check whether there is extra space in the fixed array.
-  if (index < elms_length) {
-    Handle<FixedDoubleArray> elms(FixedDoubleArray::cast(object->elements()));
-    elms->set(index, value->Number());
-    if (object->IsJSArray()) {
-      // Update the length of the array if needed.
-      uint32_t array_length = 0;
-      CHECK(Handle<JSArray>::cast(object)->length()->ToArrayLength(
-          &array_length));
-      if (index >= array_length) {
-        Handle<JSArray>::cast(object)->set_length(Smi::FromInt(index + 1));
-      }
-    }
-    return;
+  // Increase backing store capacity if that's been decided previously.
+  if (capacity != new_capacity) {
+    ElementsAccessor* accessor = object->GetElementsAccessor();
+    accessor->GrowCapacityAndConvert(object, new_capacity);
   }
 
-  // Allow gap in fast case.
-  if ((index - elms_length) < kMaxGap) {
-    // Try allocating extra space.
-    int new_capacity = NewElementsCapacity(index+1);
-    if (!object->ShouldConvertToSlowElements(new_capacity)) {
-      DCHECK(static_cast<uint32_t>(new_capacity) > index);
-      SetFastDoubleElementsCapacityAndLength(object, new_capacity, index + 1);
-      FixedDoubleArray::cast(object->elements())->set(index, value->Number());
-      JSObject::ValidateElements(object);
-      return;
-    }
+  if (must_update_array_length) {
+    Handle<JSArray>::cast(object)->set_length(Smi::FromInt(array_length));
   }
 
-  // Otherwise default to slow case.
-  DCHECK(object->HasFastDoubleElements());
-  DCHECK(object->map()->has_fast_double_elements());
-  DCHECK(object->elements()->IsFixedDoubleArray() ||
-         object->elements()->length() == 0);
-
-  NormalizeElements(object);
-  DCHECK(object->HasDictionaryElements());
-  AddDictionaryElement(object, index, value, NONE);
+  FixedDoubleArray::cast(object->elements())->set(index, value->Number());
+  JSObject::ValidateElements(object);
 }
 
 
@@ -13023,25 +12915,23 @@ void JSObject::UpdateAllocationSite(Handle<JSObject> object,
 
 void JSObject::TransitionElementsKind(Handle<JSObject> object,
                                       ElementsKind to_kind) {
-  ElementsKind from_kind = object->map()->elements_kind();
+  ElementsKind from_kind = object->GetElementsKind();
 
   if (IsFastHoleyElementsKind(from_kind)) {
     to_kind = GetHoleyElementsKind(to_kind);
   }
 
   if (from_kind == to_kind) return;
-  // Don't update the site if to_kind isn't fast
-  if (IsFastElementsKind(to_kind)) {
-    UpdateAllocationSite(object, to_kind);
-  }
 
-  Isolate* isolate = object->GetIsolate();
-  if (object->elements() == isolate->heap()->empty_fixed_array() ||
-      (IsFastSmiOrObjectElementsKind(from_kind) &&
-       IsFastSmiOrObjectElementsKind(to_kind)) ||
-      (from_kind == FAST_DOUBLE_ELEMENTS &&
-       to_kind == FAST_HOLEY_DOUBLE_ELEMENTS)) {
-    DCHECK(from_kind != TERMINAL_FAST_ELEMENTS_KIND);
+  // This method should never be called for any other case.
+  DCHECK(IsFastElementsKind(from_kind));
+  DCHECK(IsFastElementsKind(to_kind));
+  DCHECK_NE(TERMINAL_FAST_ELEMENTS_KIND, from_kind);
+
+  UpdateAllocationSite(object, to_kind);
+  if (object->elements() == object->GetHeap()->empty_fixed_array() ||
+      IsFastDoubleElementsKind(from_kind) ==
+          IsFastDoubleElementsKind(to_kind)) {
     // No change is needed to the elements() buffer, the transition
     // only requires a map change.
     Handle<Map> new_map = GetElementsTransitionMap(object, to_kind);
@@ -13050,42 +12940,14 @@ void JSObject::TransitionElementsKind(Handle<JSObject> object,
       Handle<FixedArrayBase> elms(object->elements());
       PrintElementsTransition(stdout, object, from_kind, elms, to_kind, elms);
     }
-    return;
-  }
-
-  Handle<FixedArrayBase> elms(object->elements());
-  uint32_t capacity = static_cast<uint32_t>(elms->length());
-  uint32_t length = capacity;
-
-  if (object->IsJSArray()) {
-    Object* raw_length = Handle<JSArray>::cast(object)->length();
-    if (raw_length->IsUndefined()) {
-      // If length is undefined, then JSArray is being initialized and has no
-      // elements, assume a length of zero.
-      length = 0;
-    } else {
-      CHECK(raw_length->ToArrayLength(&length));
-    }
-  }
-
-  if (IsFastSmiElementsKind(from_kind) &&
-      IsFastDoubleElementsKind(to_kind)) {
-    SetFastDoubleElementsCapacityAndLength(object, capacity, length);
-    JSObject::ValidateElements(object);
-    return;
-  }
-
-  if (IsFastDoubleElementsKind(from_kind) &&
-      IsFastObjectElementsKind(to_kind)) {
-    SetFastElementsCapacityAndLength(object, capacity, length,
-                                     kDontAllowSmiElements);
-    JSObject::ValidateElements(object);
-    return;
+  } else {
+    DCHECK((IsFastSmiElementsKind(from_kind) &&
+            IsFastDoubleElementsKind(to_kind)) ||
+           (IsFastDoubleElementsKind(from_kind) &&
+            IsFastObjectElementsKind(to_kind)));
+    uint32_t c = static_cast<uint32_t>(object->elements()->length());
+    ElementsAccessor::ForKind(to_kind)->GrowCapacityAndConvert(object, c);
   }
-
-  // This method should never be called for any other case than the ones
-  // handled above.
-  UNREACHABLE();
 }
 
 
@@ -13300,29 +13162,23 @@ bool JSObject::ShouldConvertToFastElements() {
 }
 
 
-bool JSObject::ShouldConvertToFastDoubleElements(
-    bool* has_smi_only_elements) {
-  *has_smi_only_elements = false;
-  if (HasSloppyArgumentsElements()) return false;
-  if (FLAG_unbox_double_arrays) {
-    DCHECK(HasDictionaryElements());
-    SeededNumberDictionary* dictionary = element_dictionary();
-    bool found_double = false;
-    for (int i = 0; i < dictionary->Capacity(); i++) {
-      Object* key = dictionary->KeyAt(i);
-      if (key->IsNumber()) {
-        Object* value = dictionary->ValueAt(i);
-        if (!value->IsNumber()) return false;
-        if (!value->IsSmi()) {
-          found_double = true;
-        }
+ElementsKind JSObject::BestFittingFastElementsKind() {
+  if (HasSloppyArgumentsElements()) return FAST_HOLEY_ELEMENTS;
+  DCHECK(HasDictionaryElements());
+  SeededNumberDictionary* dictionary = element_dictionary();
+  ElementsKind kind = FAST_HOLEY_SMI_ELEMENTS;
+  for (int i = 0; i < dictionary->Capacity(); i++) {
+    Object* key = dictionary->KeyAt(i);
+    if (key->IsNumber()) {
+      Object* value = dictionary->ValueAt(i);
+      if (!value->IsNumber()) return FAST_HOLEY_ELEMENTS;
+      if (!value->IsSmi()) {
+        if (!FLAG_unbox_double_arrays) return FAST_HOLEY_ELEMENTS;
+        kind = FAST_HOLEY_DOUBLE_ELEMENTS;
       }
     }
-    *has_smi_only_elements = !found_double;
-    return found_double;
-  } else {
-    return false;
   }
+  return kind;
 }