[builtins] implement Array.prototype.includes in TurboFan

src/runtime/runtime-array.cc

 // Copyright 2014 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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/code-stubs.h"
 #include "src/conversions-inl.h"
 #include "src/elements.h"
@@ skipping 14 matching lines @@
   CHECK(length->IsSmi());
   CHECK(Smi::cast(length)->value() == 0);
   CHECK(prototype->HasFastSmiOrObjectElements());
   // This is necessary to enable fast checks for absence of elements
   // on Array.prototype and below.
   prototype->set_elements(isolate->heap()->empty_fixed_array());
   return Smi::FromInt(0);
 }
 
 static void InstallCode(Isolate* isolate, Handle<JSObject> holder,
-                        const char* name, Handle<Code> code) {
+                        const char* name, Handle<Code> code, int argc = -1) {
   Handle<String> key = isolate->factory()->InternalizeUtf8String(name);
   Handle<JSFunction> optimized =
       isolate->factory()->NewFunctionWithoutPrototype(key, code);
-  optimized->shared()->DontAdaptArguments();
+  if (argc < 0) {
+    optimized->shared()->DontAdaptArguments();
+  } else {
+    optimized->shared()->set_internal_formal_parameter_count(argc);
+  }
   JSObject::AddProperty(holder, key, optimized, NONE);
 }
 
 static void InstallBuiltin(Isolate* isolate, Handle<JSObject> holder,
-                           const char* name, Builtins::Name builtin_name) {
+                           const char* name, Builtins::Name builtin_name,
+                           int argc = -1) {
   InstallCode(isolate, holder, name,
-              handle(isolate->builtins()->builtin(builtin_name), isolate));
+              handle(isolate->builtins()->builtin(builtin_name), isolate),
+              argc);
 }
 
 RUNTIME_FUNCTION(Runtime_SpecialArrayFunctions) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
   Handle<JSObject> holder =
       isolate->factory()->NewJSObject(isolate->object_function());
 
   InstallBuiltin(isolate, holder, "pop", Builtins::kArrayPop);
   FastArrayPushStub stub(isolate);
   InstallCode(isolate, holder, "push", stub.GetCode());
   InstallBuiltin(isolate, holder, "shift", Builtins::kArrayShift);
   InstallBuiltin(isolate, holder, "unshift", Builtins::kArrayUnshift);
   InstallBuiltin(isolate, holder, "slice", Builtins::kArraySlice);
   InstallBuiltin(isolate, holder, "splice", Builtins::kArraySplice);
+  InstallBuiltin(isolate, holder, "includes", Builtins::kArrayIncludes, 2);
 
   return *holder;
 }
 
 
 RUNTIME_FUNCTION(Runtime_FixedArrayGet) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_CHECKED(FixedArray, object, 0);
   CONVERT_SMI_ARG_CHECKED(index, 1);
@@ skipping 359 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_ArraySpeciesConstructor) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, original_array, 0);
   RETURN_RESULT_OR_FAILURE(
       isolate, Object::ArraySpeciesConstructor(isolate, original_array));
 }
 
+static inline Object* FastArrayIncludes(Isolate* isolate,
+                                        Handle<JSObject> object,
+                                        Handle<Object> value, uint32_t k,
+                                        uint32_t len) {
+  ElementsAccessor* elements = object->GetElementsAccessor();
+  Maybe<bool> result = elements->IncludesValue(isolate, object, value, k, len);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  if (result.FromJust()) {
+    return isolate->heap()->true_value();
+  } else {
+    return isolate->heap()->false_value();
+  }

[Camillo Bruni, 2016/07/21 08:01:55]

nit: isolate->heap()->ToBoolean(result.FromJust());

+}
+
+// ES7 22.1.3.11 Array.prototype.includes
+RUNTIME_FUNCTION(Runtime_ArrayIncludes_Slow) {
+  HandleScope shs(isolate);

[Camillo Bruni, 2016/07/21 08:01:55]

uber-nit: shs => sh (it's not a SealedHandleScope)

+  DCHECK(args.length() == 3);

[Camillo Bruni, 2016/07/21 08:01:55]

nit: DCHECK_EQ

+  CONVERT_ARG_HANDLE_CHECKED(Object, search_element, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, from_index_, 2);
+
+  // 1. Let O be ? ToObject(this value).
+  Handle<JSReceiver> object;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, object, Object::ToObject(isolate, handle(args[0], isolate)));
+
+  // 2. Let len be ? ToLength(? Get(O, "length")).

[Camillo Bruni, 2016/07/21 08:01:55]

Maybe add a shortcut for JS_ARRAY instance types directly reading the length
from the accessor, avoiding a full-fledged lookup.

+  Handle<Object> len_;
+  Handle<String> length_string =
+      handle(isolate->heap()->length_string(), isolate);

[Camillo Bruni, 2016/07/21 08:01:55]

nit: isolate->factory()->length_string() returns directly a handle

+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, len_, Object::GetProperty(object, length_string));
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, len_,
+                                     Object::ToLength(isolate, len_));
+  int64_t len = static_cast<int64_t>(len_->Number());
+  DCHECK_EQ(len, len_->Number());
+
+  // 3. If len is 0, return false.
+  if (len == 0) return isolate->heap()->false_value();
+
+  // 4. Let n be ? ToInteger(fromIndex). (If fromIndex is undefined,
+  //    this step produces the value 0.)
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, from_index_,
+                                     Object::ToInteger(isolate, from_index_));
+  if (std::isinf(from_index_->Number()) && from_index_->Number() > 0.0) {
+    return isolate->heap()->false_value();
+  }
+  int64_t from_index = static_cast<int64_t>(from_index_->Number());
+
+  int64_t k;

[Camillo Bruni, 2016/07/21 08:01:55]

nit: despite the spec, can you give reasonable variable names, something like
start_index?

[caitp, 2016/07/21 20:32:29]

Done.

+  if (from_index >= 0) {
+    k = from_index;
+  } else {
+    k = len + from_index;
+    if (k < 0) {
+      k = 0;
+    }
+  }
+
+  // In the slow path, we can still take a fast path similar to the TurboFan
+  // implementation if there are no elements in the prototype, and if the length
+  // is within elements boundaries.
+  //
+  // This would apply to Array-like Objects with no elements in the prototype,
+  // for example.
+  if (object->map()->instance_type() > LAST_SPECIAL_RECEIVER_TYPE &&
+      len < std::numeric_limits<uint32_t>::max() &&
+      JSObject::PrototypeHasNoElements(isolate, JSObject::cast(*object))) {
+    return FastArrayIncludes(isolate, Handle<JSObject>::cast(object),
+                             search_element, static_cast<uint32_t>(k),
+                             static_cast<uint32_t>(len));
+  }
+
+  // Otherwise, perform slow lookups for JSProxies and API objects, or for
+  // objects with long `length` values.
+  for (; k < len; ++k) {
+    Handle<Object> element_k;
+
+    Handle<Object> index = isolate->factory()->NewNumberFromInt64(k);
+
+    bool success;
+    LookupIterator it =
+        LookupIterator::PropertyOrElement(isolate, object, index, &success);
+    DCHECK(success);
+
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, element_k,
+                                       Object::GetProperty(&it));
+
+    if (search_element->SameValueZero(*element_k)) {
+      return isolate->heap()->true_value();
+    }
+  }
+  return isolate->heap()->false_value();
+}
+
 }  // namespace internal
 }  // namespace v8