[stubs] Port FastNewObjectStub to TF

src/code-stub-assembler.cc

Index: src/code-stub-assembler.cc
diff --git a/src/code-stub-assembler.cc b/src/code-stub-assembler.cc
index d0b63225a00904cdd6c8ac5e402121ad13b95a66..d7c47a90ac8a4adeae158ddd39916a38472c1926 100644
--- a/src/code-stub-assembler.cc
+++ b/src/code-stub-assembler.cc
@@ -1065,6 +1065,11 @@ Node* CodeStubAssembler::HasInstanceType(Node* object,
   return Word32Equal(LoadInstanceType(object), Int32Constant(instance_type));
 }
 
+Node* CodeStubAssembler::DoesntHaveInstanceType(Node* object,
+                                                InstanceType instance_type) {
+  return Word32NotEqual(LoadInstanceType(object), Int32Constant(instance_type));
+}
+
 Node* CodeStubAssembler::LoadProperties(Node* object) {
   return LoadObjectField(object, JSObject::kPropertiesOffset);
 }
@@ -6353,6 +6358,20 @@ void CodeStubAssembler::BuildFastFixedArrayForEach(
                                               : IndexAdvanceMode::kPost);
 }
 
+void CodeStubAssembler::InitializeFieldsWithRoot(
+    Node* object, Node* start_offset, Node* end_offset,
+    Heap::RootListIndex root_index) {
+  start_offset = IntPtrAdd(start_offset, IntPtrConstant(-kHeapObjectTag));
+  end_offset = IntPtrAdd(end_offset, IntPtrConstant(-kHeapObjectTag));
+  Node* root_value = LoadRoot(root_index);
+  BuildFastLoop(MachineType::PointerRepresentation(), end_offset, start_offset,
+                [this, object, root_value](Node* current) {
+                  StoreNoWriteBarrier(MachineRepresentation::kTagged, object,
+                                      current, root_value);
+                },
+                -kPointerSize, CodeStubAssembler::IndexAdvanceMode::kPre);
+}
+
 void CodeStubAssembler::BranchIfNumericRelationalComparison(
     RelationalComparisonMode mode, Node* lhs, Node* rhs, Label* if_true,
     Label* if_false) {