Allocation Info Tracking, continued.

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index 1b6c433e37e61c1f6e5f09cb7535a0be7d5d3444..779764ea7b452de227241785803b6f2fe3154dd7 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -1978,6 +1978,11 @@ MUST_USE_RESULT MaybeObject* ArrayConstructInitializeElements(
     JSArray* array, Arguments* args) {
   Heap* heap = array->GetIsolate()->heap();
 
+  // Optimize the case where there are no parameters passed.
+  if (args->length() == 0) {
+    return array->Initialize(JSArray::kPreallocatedArrayElements);
+  }
+
   // Optimize the case where there is one argument and the argument is a
   // small smi.
   if (args->length() == 1) {
@@ -1985,41 +1990,27 @@ MUST_USE_RESULT MaybeObject* ArrayConstructInitializeElements(
     if (obj->IsSmi()) {
       int len = Smi::cast(obj)->value();
       if (len > 0 && len < JSObject::kInitialMaxFastElementArray) {
-        FixedArrayBase* fixed_array;
         ElementsKind elements_kind = array->GetElementsKind();
-        {
-          MaybeObject* maybe_obj;
-          if (IsFastDoubleElementsKind(elements_kind)) {
-            maybe_obj = heap->AllocateFixedDoubleArrayWithHoles(len);
-          } else {
-            maybe_obj = heap->AllocateFixedArrayWithHoles(len);
-          }
-          if (!maybe_obj->To(&fixed_array)) return maybe_obj;
-        }
+        MaybeObject* maybe_array = array->Initialize(len, len);
+        if (maybe_array->IsFailure()) return maybe_array;
+
         if (!IsFastHoleyElementsKind(elements_kind)) {
           elements_kind = GetHoleyElementsKind(elements_kind);
-          MaybeObject* maybe_array =
-              array->TransitionElementsKind(elements_kind);
+          maybe_array = array->TransitionElementsKind(elements_kind);
           if (maybe_array->IsFailure()) return maybe_array;
         }
-        // We do not use SetContent to skip the unnecessary elements type check.
-        array->set_elements(fixed_array);
-        array->set_length(Smi::cast(obj));
+
         return array;
       } else if (len == 0) {
         return array->Initialize(JSArray::kPreallocatedArrayElements);
       }
     }
+
     // Take the argument as the length.
-    { MaybeObject* maybe_obj = array->Initialize(0);
-      if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-    }
-    return array->SetElementsLength((*args)[0]);
-  }
+    MaybeObject* maybe_obj = array->Initialize(0);
+    if (!maybe_obj->To(&obj)) return maybe_obj;
 
-  // Optimize the case where there are no parameters passed.
-  if (args->length() == 0) {
-    return array->Initialize(JSArray::kPreallocatedArrayElements);
+    return array->SetElementsLength((*args)[0]);
   }
 
   // Set length and elements on the array.