[ignition] Optimize JSGenerator creation

src/builtins/builtins-constructor-gen.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins/builtins-constructor-gen.h"
 
 #include "src/ast/ast.h"
 #include "src/builtins/builtins-constructor.h"
 #include "src/builtins/builtins-utils-gen.h"
 #include "src/builtins/builtins.h"
@@ skipping 241 matching lines @@
   BIND(&allocate_properties);
   {
     properties.Bind(AllocateNameDictionary(NameDictionary::kInitialCapacity));
     Goto(&instantiate_map);
   }
 
   BIND(&instantiate_map);
 
   Node* object = AllocateJSObjectFromMap(initial_map, properties.value());
 
-  Node* instance_size_words = ChangeUint32ToWord(LoadObjectField(
-      initial_map, Map::kInstanceSizeOffset, MachineType::Uint8()));
-  Node* instance_size =
-      WordShl(instance_size_words, IntPtrConstant(kPointerSizeLog2));
-
   // Perform in-object slack tracking if requested.
-  Node* bit_field3 = LoadMapBitField3(initial_map);
-  Label slack_tracking(this), finalize(this, Label::kDeferred), done(this);
-  GotoIf(IsSetWord32<Map::ConstructionCounter>(bit_field3), &slack_tracking);
-
-  // Initialize remaining fields.
-  {
-    Comment("no slack tracking");
-    InitializeFieldsWithRoot(object, IntPtrConstant(JSObject::kHeaderSize),
-                             instance_size, Heap::kUndefinedValueRootIndex);
-    Goto(&end);
-  }
-
-  {
-    BIND(&slack_tracking);
-
-    // Decrease generous allocation count.
-    STATIC_ASSERT(Map::ConstructionCounter::kNext == 32);
-    Comment("update allocation count");
-    Node* new_bit_field3 = Int32Sub(
-        bit_field3, Int32Constant(1 << Map::ConstructionCounter::kShift));
-    StoreObjectFieldNoWriteBarrier(initial_map, Map::kBitField3Offset,
-                                   new_bit_field3,
-                                   MachineRepresentation::kWord32);
-    GotoIf(IsClearWord32<Map::ConstructionCounter>(new_bit_field3), &finalize);
-
-    Node* unused_fields = LoadObjectField(
-        initial_map, Map::kUnusedPropertyFieldsOffset, MachineType::Uint8());
-    Node* used_size =
-        IntPtrSub(instance_size, WordShl(ChangeUint32ToWord(unused_fields),
-                                         IntPtrConstant(kPointerSizeLog2)));
-
-    Comment("initialize filler fields (no finalize)");
-    InitializeFieldsWithRoot(object, used_size, instance_size,
-                             Heap::kOnePointerFillerMapRootIndex);
-
-    Comment("initialize undefined fields (no finalize)");
-    InitializeFieldsWithRoot(object, IntPtrConstant(JSObject::kHeaderSize),
-                             used_size, Heap::kUndefinedValueRootIndex);
-    Goto(&end);
-  }
-
-  {
-    // Finalize the instance size.
-    BIND(&finalize);
-
-    Node* unused_fields = LoadObjectField(
-        initial_map, Map::kUnusedPropertyFieldsOffset, MachineType::Uint8());
-    Node* used_size =
-        IntPtrSub(instance_size, WordShl(ChangeUint32ToWord(unused_fields),
-                                         IntPtrConstant(kPointerSizeLog2)));
-
-    Comment("initialize filler fields (finalize)");
-    InitializeFieldsWithRoot(object, used_size, instance_size,
-                             Heap::kOnePointerFillerMapRootIndex);
-
-    Comment("initialize undefined fields (finalize)");
-    InitializeFieldsWithRoot(object, IntPtrConstant(JSObject::kHeaderSize),
-                             used_size, Heap::kUndefinedValueRootIndex);
-
-    CallRuntime(Runtime::kFinalizeInstanceSize, context, initial_map);
-    Goto(&end);
-  }
-
-  BIND(&end);
+  HandleSlackTracking(context, object, initial_map, JSObject::kHeaderSize);
   return object;
 }
 
 Node* ConstructorBuiltinsAssembler::EmitFastNewFunctionContext(
     Node* function, Node* slots, Node* context, ScopeType scope_type) {
   slots = ChangeUint32ToWord(slots);
 
   // TODO(ishell): Use CSA::OptimalParameterMode() here.
   ParameterMode mode = INTPTR_PARAMETERS;
   Node* min_context_slots = IntPtrConstant(Context::MIN_CONTEXT_SLOTS);
@@ skipping 394 matching lines @@
 SHALLOW_OBJECT_BUILTIN(0);
 SHALLOW_OBJECT_BUILTIN(1);
 SHALLOW_OBJECT_BUILTIN(2);
 SHALLOW_OBJECT_BUILTIN(3);
 SHALLOW_OBJECT_BUILTIN(4);
 SHALLOW_OBJECT_BUILTIN(5);
 SHALLOW_OBJECT_BUILTIN(6);
 
 }  // namespace internal
 }  // namespace v8