deps: cherry-pick d721121 from v8 upstream

bnoordhuis · ofrobots · commit fc442e0f434c · 2016-08-25T10:33:50.000-07:00
Original commit message: Quit creating array literal boilerplates from Crankshaft. It's such a corner case. BUG= Review URL: https://codereview.chromium.org/1865013002 Cr-Commit-Position: refs/heads/master@{#35346} Fixes: #7454 PR-URL: #7632 Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
diff --git a/deps/v8/src/crankshaft/hydrogen.cc b/deps/v8/src/crankshaft/hydrogen.cc
@@ -5995,59 +5995,34 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
   Handle<AllocationSite> site;
   Handle<LiteralsArray> literals(environment()->closure()->literals(),
                                  isolate());
-  bool uninitialized = false;
   Handle<Object> literals_cell(literals->literal(expr->literal_index()),
                                isolate());
   Handle<JSObject> boilerplate_object;
-  if (literals_cell->IsUndefined()) {
-    uninitialized = true;
-    Handle<Object> raw_boilerplate;
-    ASSIGN_RETURN_ON_EXCEPTION_VALUE(
-        isolate(), raw_boilerplate,
-        Runtime::CreateArrayLiteralBoilerplate(isolate(), literals,
-                                               expr->constant_elements()),
-        Bailout(kArrayBoilerplateCreationFailed));
-
-    boilerplate_object = Handle<JSObject>::cast(raw_boilerplate);
-    AllocationSiteCreationContext creation_context(isolate());
-    site = creation_context.EnterNewScope();
-    if (JSObject::DeepWalk(boilerplate_object, &creation_context).is_null()) {
-      return Bailout(kArrayBoilerplateCreationFailed);
-    }
-    creation_context.ExitScope(site, boilerplate_object);
-    literals->set_literal(expr->literal_index(), *site);
-
-    if (boilerplate_object->elements()->map() ==
-        isolate()->heap()->fixed_cow_array_map()) {
-      isolate()->counters()->cow_arrays_created_runtime()->Increment();
-    }
-  } else {
+  if (!literals_cell->IsUndefined()) {
     DCHECK(literals_cell->IsAllocationSite());
     site = Handle<AllocationSite>::cast(literals_cell);
     boilerplate_object = Handle<JSObject>(
         JSObject::cast(site->transition_info()), isolate());
   }
 
-  DCHECK(!boilerplate_object.is_null());
-  DCHECK(site->SitePointsToLiteral());
-
-  ElementsKind boilerplate_elements_kind =
-      boilerplate_object->GetElementsKind();
+  ElementsKind boilerplate_elements_kind = expr->constant_elements_kind();
+  if (!boilerplate_object.is_null()) {
+    boilerplate_elements_kind = boilerplate_object->GetElementsKind();
+  }
 
   // Check whether to use fast or slow deep-copying for boilerplate.
   int max_properties = kMaxFastLiteralProperties;
-  if (IsFastLiteral(boilerplate_object,
-                    kMaxFastLiteralDepth,
+  if (!boilerplate_object.is_null() &&
+      IsFastLiteral(boilerplate_object, kMaxFastLiteralDepth,
                     &max_properties)) {
+    DCHECK(site->SitePointsToLiteral());
     AllocationSiteUsageContext site_context(isolate(), site, false);
     site_context.EnterNewScope();
     literal = BuildFastLiteral(boilerplate_object, &site_context);
     site_context.ExitScope(site, boilerplate_object);
   } else {
     NoObservableSideEffectsScope no_effects(this);
-    // Boilerplate already exists and constant elements are never accessed,
-    // pass an empty fixed array to the runtime function instead.
-    Handle<FixedArray> constants = isolate()->factory()->empty_fixed_array();
+    Handle<FixedArray> constants = expr->constant_elements();
     int literal_index = expr->literal_index();
     int flags = expr->ComputeFlags(true);
 
@@ -6058,7 +6033,9 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
     literal = Add<HCallRuntime>(Runtime::FunctionForId(function_id), 4);
 
     // Register to deopt if the boilerplate ElementsKind changes.
-    top_info()->dependencies()->AssumeTransitionStable(site);
+    if (!site.is_null()) {
+      top_info()->dependencies()->AssumeTransitionStable(site);
+    }
   }
 
   // The array is expected in the bailout environment during computation
@@ -6090,9 +6067,8 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
       case FAST_HOLEY_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
       case FAST_HOLEY_DOUBLE_ELEMENTS: {
-        HStoreKeyed* instr = Add<HStoreKeyed>(elements, key, value, nullptr,
-                                              boilerplate_elements_kind);
-        instr->SetUninitialized(uninitialized);
+        Add<HStoreKeyed>(elements, key, value, nullptr,
+                         boilerplate_elements_kind);
         break;
       }
       default:
diff --git a/deps/v8/src/runtime/runtime-literals.cc b/deps/v8/src/runtime/runtime-literals.cc
@@ -109,7 +109,7 @@ MUST_USE_RESULT static MaybeHandle<Object> CreateObjectLiteralBoilerplate(
   return boilerplate;
 }
 
-MaybeHandle<Object> Runtime::CreateArrayLiteralBoilerplate(
+static MaybeHandle<Object> CreateArrayLiteralBoilerplate(
     Isolate* isolate, Handle<LiteralsArray> literals,
     Handle<FixedArray> elements) {
   // Create the JSArray.
@@ -191,8 +191,7 @@ MUST_USE_RESULT static MaybeHandle<Object> CreateLiteralBoilerplate(
     case CompileTimeValue::OBJECT_LITERAL_SLOW_ELEMENTS:
       return CreateObjectLiteralBoilerplate(isolate, literals, elements, false);
     case CompileTimeValue::ARRAY_LITERAL:
-      return Runtime::CreateArrayLiteralBoilerplate(isolate, literals,
-                                                    elements);
+      return CreateArrayLiteralBoilerplate(isolate, literals, elements);
     default:
       UNREACHABLE();
       return MaybeHandle<Object>();
@@ -280,7 +279,7 @@ MUST_USE_RESULT static MaybeHandle<AllocationSite> GetLiteralAllocationSite(
     Handle<Object> boilerplate;
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, boilerplate,
-        Runtime::CreateArrayLiteralBoilerplate(isolate, literals, elements),
+        CreateArrayLiteralBoilerplate(isolate, literals, elements),
         AllocationSite);
 
     AllocationSiteCreationContext creation_context(isolate);
diff --git a/deps/v8/src/runtime/runtime.h b/deps/v8/src/runtime/runtime.h
@@ -1130,11 +1130,6 @@ class Runtime : public AllStatic {
                                    ElementsKind* fixed_elements_kind,
                                    size_t* element_size);
 
-  // Used in runtime.cc and hydrogen's VisitArrayLiteral.
-  MUST_USE_RESULT static MaybeHandle<Object> CreateArrayLiteralBoilerplate(
-      Isolate* isolate, Handle<LiteralsArray> literals,
-      Handle<FixedArray> elements);
-
   static MaybeHandle<JSArray> GetInternalProperties(Isolate* isolate,
                                                     Handle<Object>);
 };
