[array] Fast allocation in Array.p.map

src/builtins/builtins-array-gen.cc

Index: src/builtins/builtins-array-gen.cc
diff --git a/src/builtins/builtins-array-gen.cc b/src/builtins/builtins-array-gen.cc
index abe31e6ce8f7c097f3c9919419791a288ae85912..ca553b73ceb6b643831d5249eec1f6c647c985da 100644
--- a/src/builtins/builtins-array-gen.cc
+++ b/src/builtins/builtins-array-gen.cc
@@ -91,7 +91,8 @@ class ArrayBuiltinCodeStubAssembler : public CodeStubAssembler {
 
   void FilterResultGenerator() {
     // 7. Let A be ArraySpeciesCreate(O, 0).
-    a_.Bind(ArraySpeciesCreate(context(), o(), SmiConstant(0)));
+    Node* len = SmiConstant(0);
+    ArraySpeciesCreate(len);
   }
 
   Node* FilterProcessor(Node* k_value, Node* k) {
@@ -160,37 +161,7 @@ class ArrayBuiltinCodeStubAssembler : public CodeStubAssembler {
     return a();
   }
 
-  void MapResultGenerator() {
-    Label runtime(this), done(this, {&a_});
-    GotoIf(DoesntHaveInstanceType(o(), JS_ARRAY_TYPE), &runtime);
-    Node* o_map = LoadMap(o());
-    Node* const initial_array_prototype = LoadContextElement(
-        LoadNativeContext(context()), Context::INITIAL_ARRAY_PROTOTYPE_INDEX);
-    Node* proto = LoadMapPrototype(o_map);
-    GotoIf(WordNotEqual(proto, initial_array_prototype), &runtime);
-
-    Node* species_protector = SpeciesProtectorConstant();
-    Node* value = LoadObjectField(species_protector, Cell::kValueOffset);
-    Node* const protector_invalid = SmiConstant(Isolate::kProtectorInvalid);
-    GotoIf(WordEqual(value, protector_invalid), &runtime);
-
-    Node* const initial_array_constructor = LoadContextElement(
-        LoadNativeContext(context()), Context::ARRAY_FUNCTION_INDEX);
-    a_.Bind(ConstructJS(CodeFactory::Construct(isolate()), context(),
-                        initial_array_constructor, len_));
-    Goto(&done);
-
-    BIND(&runtime);
-    {
-      // 5. Let A be ? ArraySpeciesCreate(O, len).
-      Node* constructor =
-          CallRuntime(Runtime::kArraySpeciesConstructor, context(), o());
-      a_.Bind(ConstructJS(CodeFactory::Construct(isolate()), context(),
-                          constructor, len_));
-      Goto(&fully_spec_compliant_);
-    }
-    BIND(&done);
-  }
+  void MapResultGenerator() { ArraySpeciesCreate(len_); }
 
   Node* SpecCompliantMapProcessor(Node* k_value, Node* k) {
     //  i. Let kValue be ? Get(O, Pk). Performed by the caller of
@@ -716,6 +687,51 @@ class ArrayBuiltinCodeStubAssembler : public CodeStubAssembler {
     }
   }
 
+  // Perform ArraySpeciesCreate (ES6 #sec-arrayspeciescreate).
+  void ArraySpeciesCreate(Node* len) {
+    Label runtime(this, Label::kDeferred), done(this);
+
+    Node* const original_map = LoadMap(o());
+    GotoIf(Word32NotEqual(LoadMapInstanceType(original_map),
+                          Int32Constant(JS_ARRAY_TYPE)),
+           &runtime);
+
+    Node* const native_context = LoadNativeContext(context());
+    Node* const initial_array_prototype = LoadContextElement(
+        native_context, Context::INITIAL_ARRAY_PROTOTYPE_INDEX);
+    Node* proto = LoadMapPrototype(original_map);
+    GotoIf(WordNotEqual(proto, initial_array_prototype), &runtime);
+
+    Node* species_protector = SpeciesProtectorConstant();
+    Node* value = LoadObjectField(species_protector, Cell::kValueOffset);
+    Node* const protector_invalid = SmiConstant(Isolate::kProtectorInvalid);
+    GotoIf(WordEqual(value, protector_invalid), &runtime);
+
+    GotoIfNot(TaggedIsPositiveSmi(len), &runtime);
+    GotoIf(SmiAbove(len, SmiConstant(JSArray::kInitialMaxFastElementArray)),
+           &runtime);
+
+    const ElementsKind elements_kind =
+        GetHoleyElementsKind(GetInitialFastElementsKind());
+    Node* array_map = LoadJSArrayElementsMap(elements_kind, native_context);
+    a_.Bind(AllocateJSArray(FAST_SMI_ELEMENTS, array_map, len, len, nullptr,
+                            CodeStubAssembler::SMI_PARAMETERS));
+
+    Goto(&done);
+
+    BIND(&runtime);
+    {
+      // 5. Let A be ? ArraySpeciesCreate(O, len).
+      Node* constructor =
+          CallRuntime(Runtime::kArraySpeciesConstructor, context(), o());
+      a_.Bind(ConstructJS(CodeFactory::Construct(isolate()), context(),
+                          constructor, len));
+      Goto(&fully_spec_compliant_);
+    }
+
+    BIND(&done);
+  }
+
   Node* callbackfn_ = nullptr;
   Node* o_ = nullptr;
   Node* this_arg_ = nullptr;