Revert "[builtins] Enable Torque Array.prototype.splice"

This reverts commit ff4fa92e.

Reason for revert: blocks roll: https://chromium-review.googlesource.com/c/chromium/src/+/1167969 ... see https://chromium-swarm.appspot.com/task?id=3f344f7ada4e0110&refresh=10&show_raw=1 for stacktrace.

Original change's description:
> [builtins] Enable Torque Array.prototype.splice
> 
> Before, splice was implemented with a C++ fast path and a
> comprehensive JavaScript version.
> 
> This impl. is entirely in Torque with a fastpath for SMI,
> DOUBLE and OBJECT arrays, and a comprehensive slow path.
> The same level of "sparse" array support as given by the
> array.js implementation is included.
> 
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Ibfa3407ed75b9ad15ac54cce446b3952e38f90a9
> Reviewed-on: https://chromium-review.googlesource.com/1039190
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Michael Stanton <mvstanton@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54974}

TBR=danno@chromium.org,yangguo@chromium.org,mvstanton@chromium.org,tebbi@chromium.org,szuend@google.com

Change-Id: I900f667b30a0cf673ead9621618a9988cf85ffdf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/1168902
Commit-Queue: Michael Hablich <hablich@chromium.org>
Reviewed-by: Michael Hablich <hablich@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54998}

BUILD.gn

@@ -872,7 +872,6 @@ torque_files = [
   "src/builtins/array.tq",
   "src/builtins/array-foreach.tq",
   "src/builtins/array-sort.tq",
-  "src/builtins/array-splice.tq",
   "src/builtins/typed-array.tq",
   "src/builtins/data-view.tq",
   "test/torque/test-torque.tq",

src/bootstrapper.cc

@@ -1738,8 +1738,13 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                           1, false);
     SimpleInstallFunction(isolate_, proto, "slice",
                           Builtins::kArrayPrototypeSlice, 2, false);
-    SimpleInstallFunction(isolate_, proto, "splice", Builtins::kArraySplice, 2,
-                          false);
+    if (FLAG_enable_experimental_builtins) {
+      SimpleInstallFunction(isolate_, proto, "splice",
+                            Builtins::kArraySpliceTorque, 2, false);
+    } else {
+      SimpleInstallFunction(isolate_, proto, "splice", Builtins::kArraySplice,
+                            2, false);
+    }
     SimpleInstallFunction(isolate_, proto, "includes", Builtins::kArrayIncludes,
                           1, false);
     SimpleInstallFunction(isolate_, proto, "indexOf", Builtins::kArrayIndexOf,

src/builtins/array-foreach.tq

@@ -61,10 +61,6 @@ module array {
       let callbackfn: Callable = cast<Callable>(callback) otherwise Unexpected;
       let k: Smi = cast<Smi>(initialK) otherwise Unexpected;
       let number_length: Number = cast<Number>(length) otherwise Unexpected;
-      // The unsafe cast is safe because all continuation points in forEach are
-      // after the ToObject(O) call that ensures we are dealing with a
-      // JSReceiver.
-      let jsreceiver: JSReceiver = unsafe_cast<JSReceiver>(object);
 
       return ArrayForEachTorqueContinuation(
           context, receiver, number_length, callbackfn, thisArg, k);

src/builtins/base.tq

@@ -106,10 +106,6 @@ type FixedUint8ClampedArray extends FixedTypedArray;
 type FixedBigUint64Array extends FixedTypedArray;
 type FixedBigInt64Array extends FixedTypedArray;
 
-const kFixedArrays: constexpr ExtractFixedArrayFlags generates
-'ExtractFixedArrayFlag::kFixedArrays';
-const kFixedDoubleArrays: constexpr ExtractFixedArrayFlags generates
-'ExtractFixedArrayFlag::kFixedDoubleArrays';
 const kAllFixedArrays: constexpr ExtractFixedArrayFlags generates
 'ExtractFixedArrayFlag::kAllFixedArrays';
 
@@ -168,7 +164,6 @@ extern macro Is64(): constexpr bool;
 
 extern macro Print(constexpr string);
 extern macro Print(constexpr string, Object);
-extern macro Comment(constexpr string);
 extern macro Print(Object);
 extern macro DebugBreak();
 extern macro ToInteger_Inline(Context, Object): Number;
@@ -193,8 +188,7 @@ extern macro ThrowTypeError(Context, constexpr MessageTemplate): never;
 extern macro ThrowTypeError(Context, constexpr MessageTemplate, Object): never;
 extern macro ThrowTypeError(
     Context, constexpr MessageTemplate, Object, Object, Object): never;
-extern macro ArraySpeciesCreate(Context, Object, Number): JSReceiver;
-extern macro InternalArrayCreate(Context, Number): JSArray;
+extern macro ArraySpeciesCreate(Context, Object, Number): Object;
 extern macro EnsureArrayPushable(Map): ElementsKind labels Bailout;
 
 extern builtin ToObject(Context, Object): JSReceiver;
@@ -203,9 +197,7 @@ extern macro IsTheHole(Object): bool;
 extern macro IsString(HeapObject): bool;
 extern builtin ToString(Context, Object): String;
 
-extern runtime NormalizeElements(Context, JSObject);
-extern runtime TransitionElementsKindWithKind(Context, JSObject, Smi);
-extern runtime CreateDataProperty(Context, JSReceiver, Object, Object);
+extern runtime CreateDataProperty(Context, Object, Object, Object);
 extern runtime SetProperty(Context, Object, Object, Object, LanguageMode);
 extern runtime DeleteProperty(Context, Object, Object, LanguageMode);
 
@@ -234,10 +226,6 @@ extern operator '>=' macro SmiGreaterThanOrEqual(Smi, Smi): bool;
 extern operator '==' macro ElementsKindEqual(
     constexpr ElementsKind, constexpr ElementsKind): constexpr bool;
 extern operator '==' macro ElementsKindEqual(ElementsKind, ElementsKind): bool;
-operator '!=' macro ElementsKindNotEqual(
-    k1: ElementsKind, k2: ElementsKind): bool {
-  return !ElementsKindEqual(k1, k2);
-}
 extern macro IsFastElementsKind(constexpr ElementsKind): constexpr bool;
 extern macro IsDoubleElementsKind(constexpr ElementsKind): constexpr bool;
 
@@ -256,14 +244,11 @@ extern operator '>=' macro UintPtrGreaterThanOrEqual(uintptr, uintptr): bool;
 extern operator '==' macro Float64Equal(float64, float64): bool;
 extern operator '!=' macro Float64NotEqual(float64, float64): bool;
 
-extern operator
-'==' macro BranchIfNumberEqual(Number, Number): never labels Taken, NotTaken;
 extern operator
 '<' macro BranchIfNumberLessThan(Number, Number): never labels Taken, NotTaken;
 extern operator
 '<=' macro BranchIfNumberLessThanOrEqual(Number, Number): never labels Taken,
     NotTaken;
-
 extern operator
 '>' macro BranchIfNumberGreaterThan(Number, Number): never labels Taken,
     NotTaken;
@@ -330,8 +315,8 @@ extern operator '.length' macro GetArgumentsLength(constexpr Arguments): intptr;
 extern operator
 '[]' macro GetArgumentValue(constexpr Arguments, intptr): Object;
 
-extern macro TaggedIsSmi(Object): bool;
-extern macro TaggedIsNotSmi(Object): bool;
+extern operator 'is<Smi>' macro TaggedIsSmi(Object): bool;
+extern operator 'isnt<Smi>' macro TaggedIsNotSmi(Object): bool;
 extern macro TaggedIsPositiveSmi(Object): bool;
 
 extern macro HeapObjectToJSDataView(HeapObject): JSDataView labels CastError;
@@ -477,13 +462,6 @@ from_constexpr<Object>(s: constexpr string): Object {
 macro convert<A : type>(i: constexpr int31): A {
   return i;
 }
-extern macro ConvertElementsKindToInt(ElementsKind): int32;
-
-macro convert<A : type>(elements_kind: ElementsKind): A;
-convert<int32>(elements_kind: ElementsKind): int32 {
-  return ConvertElementsKindToInt(elements_kind);
-}
-
 macro convert<A : type>(i: int32): A;
 convert<Number>(i: int32): Number {
   return ChangeInt32ToTagged(i);
@@ -570,9 +548,6 @@ unsafe_cast<HeapNumber>(n: Number): HeapNumber {
   return UnsafeCastNumberToHeapNumber(n);
 }
 macro unsafe_cast<A : type>(o: Object): A;
-unsafe_cast<Object>(o: Object): Object {
-  return o;
-}
 unsafe_cast<FixedArray>(o: Object): FixedArray {
   return UnsafeCastObjectToFixedArray(o);
 }
@@ -659,10 +634,6 @@ extern operator
     FixedArray, constexpr int31, Object): void;
 extern operator
 '[]=' macro StoreFixedArrayElementSmi(FixedArray, Smi, Object): void;
-operator '[]=' macro StoreFixedDoubleArrayNumber(
-    a: FixedDoubleArray, index: Smi, value: Number): void {
-  a[index] = convert<float64>(value);
-}
 
 extern operator '.instance_type' macro LoadMapInstanceType(Map): int32;
 
@@ -688,28 +659,6 @@ extern macro IsFastSmiOrTaggedElementsKind(ElementsKind): bool;
 extern macro IsFastSmiElementsKind(ElementsKind): bool;
 extern macro IsHoleyFastElementsKind(ElementsKind): bool;
 
-macro AllowDoubleElements(kind: ElementsKind): ElementsKind {
-  if (kind == PACKED_SMI_ELEMENTS) {
-    return PACKED_DOUBLE_ELEMENTS;
-  } else if (kind == HOLEY_SMI_ELEMENTS) {
-    return HOLEY_DOUBLE_ELEMENTS;
-  }
-  return kind;
-}
-
-macro AllowNonNumberElements(kind: ElementsKind): ElementsKind {
-  if (kind == PACKED_SMI_ELEMENTS) {
-    return PACKED_ELEMENTS;
-  } else if (kind == HOLEY_SMI_ELEMENTS) {
-    return HOLEY_ELEMENTS;
-  } else if (kind == PACKED_DOUBLE_ELEMENTS) {
-    return PACKED_ELEMENTS;
-  } else if (kind == HOLEY_DOUBLE_ELEMENTS) {
-    return HOLEY_ELEMENTS;
-  }
-  return kind;
-}
-
 extern macro AllocateFixedArray(constexpr ElementsKind, intptr): FixedArray;
 
 extern macro CopyFixedArrayElements(
@@ -724,13 +673,8 @@ extern macro AllocateJSArray(constexpr ElementsKind, Map, Smi, Smi): JSArray;
 extern macro IsElementsKindGreaterThan(
     ElementsKind, constexpr ElementsKind): bool;
 
-extern operator
-'[]=' macro StoreFixedDoubleArrayElementSmi(
-    FixedDoubleArray, Smi, float64): void;
-
 extern macro LoadDoubleWithHoleCheck(FixedDoubleArray, Smi): float64
 labels IfHole;
-extern macro StoreFixedDoubleArrayHoleSmi(FixedDoubleArray, Smi): void;
 
 extern macro Call(Context, Callable, Object): Object;
 extern macro Call(Context, Callable, Object, Object): Object;
@@ -741,9 +685,8 @@ extern macro Call(
 extern macro Call(
     Context, Callable, Object, Object, Object, Object, Object, Object): Object;
 
-extern macro ExtractFixedArray(FixedArray, Smi, Smi, Smi): FixedArray;
 extern macro ExtractFixedArray(
-    FixedDoubleArray, Smi, Smi, Smi): FixedDoubleArray;
+    FixedArray, Smi, Smi, Smi, constexpr ExtractFixedArrayFlags): FixedArray;
 
 extern builtin ExtractFastJSArray(Context, JSArray, Smi, Smi): JSArray;
 
@@ -778,17 +721,11 @@ labels IfHole {
   }
 }
 
-extern macro TransitionElementsKind(
-    JSObject, Map, ElementsKind, ElementsKind): void labels Bailout;
-
 extern macro IsCallable(HeapObject): bool;
 extern macro IsJSArray(HeapObject): bool;
-extern macro IsJSReceiver(HeapObject): bool;
-extern macro IsFixedArray(HeapObject): bool;
 extern macro TaggedIsCallable(Object): bool;
 extern macro IsDetachedBuffer(JSArrayBuffer): bool;
 extern macro IsHeapNumber(HeapObject): bool;
-extern macro IsNumber(Object): bool;
 extern macro IsExtensibleMap(Map): bool;
 extern macro IsCustomElementsReceiverInstanceType(int32): bool;
 extern macro Typeof(Object): Object;

src/builtins/builtins-array.cc

@@ -23,6 +23,34 @@ namespace internal {
 
 namespace {
 
+inline bool ClampedToInteger(Isolate* isolate, Object* object, int* out) {
+  // This is an extended version of ECMA-262 7.1.11 handling signed values
+  // Try to convert object to a number and clamp values to [kMinInt, kMaxInt]
+  if (object->IsSmi()) {
+    *out = Smi::ToInt(object);
+    return true;
+  } else if (object->IsHeapNumber()) {
+    double value = HeapNumber::cast(object)->value();
+    if (std::isnan(value)) {
+      *out = 0;
+    } else if (value > kMaxInt) {
+      *out = kMaxInt;
+    } else if (value < kMinInt) {
+      *out = kMinInt;
+    } else {
+      *out = static_cast<int>(value);
+    }
+    return true;
+  } else if (object->IsNullOrUndefined(isolate)) {
+    *out = 0;
+    return true;
+  } else if (object->IsBoolean()) {
+    *out = object->IsTrue(isolate);
+    return true;
+  }
+  return false;
+}
+
 inline bool IsJSArrayFastElementMovingAllowed(Isolate* isolate,
                                               JSArray* receiver) {
   return JSObject::PrototypeHasNoElements(isolate, receiver);
@@ -502,6 +530,67 @@ BUILTIN(ArrayUnshift) {
   return Smi::FromInt(new_length);
 }
 
+BUILTIN(ArraySplice) {
+  HandleScope scope(isolate);
+  Handle<Object> receiver = args.receiver();
+  if (V8_UNLIKELY(
+          !EnsureJSArrayWithWritableFastElements(isolate, receiver, &args, 3,
+                                                 args.length() - 3) ||
+          // If this is a subclass of Array, then call out to JS.
+          !Handle<JSArray>::cast(receiver)->HasArrayPrototype(isolate) ||
+          // If anything with @@species has been messed with, call out to JS.
+          !isolate->IsArraySpeciesLookupChainIntact())) {
+    return CallJsIntrinsic(isolate, isolate->array_splice(), args);
+  }
+  Handle<JSArray> array = Handle<JSArray>::cast(receiver);
+
+  int argument_count = args.length() - 1;
+  int relative_start = 0;
+  if (argument_count > 0) {
+    DisallowHeapAllocation no_gc;
+    if (!ClampedToInteger(isolate, args[1], &relative_start)) {
+      AllowHeapAllocation allow_allocation;
+      return CallJsIntrinsic(isolate, isolate->array_splice(), args);
+    }
+  }
+  int len = Smi::ToInt(array->length());
+  // clip relative start to [0, len]
+  int actual_start = (relative_start < 0) ? Max(len + relative_start, 0)
+                                          : Min(relative_start, len);
+
+  int actual_delete_count;
+  if (argument_count == 1) {
+    // SpiderMonkey, TraceMonkey and JSC treat the case where no delete count is
+    // given as a request to delete all the elements from the start.
+    // And it differs from the case of undefined delete count.
+    // This does not follow ECMA-262, but we do the same for compatibility.
+    DCHECK_GE(len - actual_start, 0);
+    actual_delete_count = len - actual_start;
+  } else {
+    int delete_count = 0;
+    DisallowHeapAllocation no_gc;
+    if (argument_count > 1) {
+      if (!ClampedToInteger(isolate, args[2], &delete_count)) {
+        AllowHeapAllocation allow_allocation;
+        return CallJsIntrinsic(isolate, isolate->array_splice(), args);
+      }
+    }
+    actual_delete_count = Min(Max(delete_count, 0), len - actual_start);
+  }
+
+  int add_count = (argument_count > 1) ? (argument_count - 2) : 0;
+  int new_length = len - actual_delete_count + add_count;
+
+  if (new_length != len && JSArray::HasReadOnlyLength(array)) {
+    AllowHeapAllocation allow_allocation;
+    return CallJsIntrinsic(isolate, isolate->array_splice(), args);
+  }
+  ElementsAccessor* accessor = array->GetElementsAccessor();
+  Handle<JSArray> result_array = accessor->Splice(
+      array, actual_start, actual_delete_count, &args, add_count);
+  return *result_array;
+}
+
 // Array Concat -------------------------------------------------------------
 
 namespace {

src/builtins/builtins-definitions.h

@@ -315,6 +315,8 @@ namespace internal {
   TFJ(ArrayPrototypeShift, SharedFunctionInfo::kDontAdaptArgumentsSentinel)    \
   /* ES6 #sec-array.prototype.slice */                                         \
   TFJ(ArrayPrototypeSlice, SharedFunctionInfo::kDontAdaptArgumentsSentinel)    \
+  /* ES6 #sec-array.prototype.splice */                                        \
+  CPP(ArraySplice)                                                             \
   /* ES6 #sec-array.prototype.unshift */                                       \
   CPP(ArrayUnshift)                                                            \
   /* Support for Array.from and other array-copying idioms */                  \

src/builtins/growable-fixed-array-gen.cc

@@ -90,8 +90,8 @@ TNode<FixedArray> GrowableFixedArray::ResizeFixedArray(
 
   CodeStubAssembler::ExtractFixedArrayFlags flags;
   flags |= CodeStubAssembler::ExtractFixedArrayFlag::kFixedArrays;
-  TNode<FixedArray> to_array = CAST(ExtractFixedArray(
-      from_array, nullptr, element_count, new_capacity, flags));
+  TNode<FixedArray> to_array = ExtractFixedArray(
+      from_array, nullptr, element_count, new_capacity, flags);
 
   return to_array;
 }

src/code-stub-assembler.cc

@@ -3858,7 +3858,7 @@ TNode<FixedArray> CodeStubAssembler::AllocateFixedArray(
   return UncheckedCast<FixedArray>(array);
 }
 
-TNode<FixedArrayBase> CodeStubAssembler::ExtractFixedArray(
+TNode<FixedArray> CodeStubAssembler::ExtractFixedArray(
     Node* fixed_array, Node* first, Node* count, Node* capacity,
     ExtractFixedArrayFlags extract_flags, ParameterMode parameter_mode) {
   VARIABLE(var_result, MachineRepresentation::kTagged);
@@ -4084,33 +4084,6 @@ void CodeStubAssembler::FillFixedArrayWithValue(
       mode);
 }
 
-void CodeStubAssembler::StoreFixedDoubleArrayHole(
-    TNode<FixedDoubleArray> array, Node* index, ParameterMode parameter_mode) {
-  CSA_SLOW_ASSERT(this, MatchesParameterMode(index, parameter_mode));
-  Node* offset =
-      ElementOffsetFromIndex(index, PACKED_DOUBLE_ELEMENTS, parameter_mode,
-                             FixedArray::kHeaderSize - kHeapObjectTag);
-  CSA_ASSERT(this, IsOffsetInBounds(
-                       offset, LoadAndUntagFixedArrayBaseLength(array),
-                       FixedDoubleArray::kHeaderSize, PACKED_DOUBLE_ELEMENTS));
-  Node* double_hole =
-      Is64() ? ReinterpretCast<UintPtrT>(Int64Constant(kHoleNanInt64))
-             : ReinterpretCast<UintPtrT>(Int32Constant(kHoleNanLower32));
-  // TODO(danno): When we have a Float32/Float64 wrapper class that
-  // preserves double bits during manipulation, remove this code/change
-  // this to an indexed Float64 store.
-  if (Is64()) {
-    StoreNoWriteBarrier(MachineRepresentation::kWord64, array, offset,
-                        double_hole);
-  } else {
-    StoreNoWriteBarrier(MachineRepresentation::kWord32, array, offset,
-                        double_hole);
-    StoreNoWriteBarrier(MachineRepresentation::kWord32, array,
-                        IntPtrAdd(offset, IntPtrConstant(kPointerSize)),
-                        double_hole);
-  }
-}
-
 void CodeStubAssembler::CopyFixedArrayElements(
     ElementsKind from_kind, Node* from_array, ElementsKind to_kind,
     Node* to_array, Node* first_element, Node* element_count, Node* capacity,
@@ -9844,9 +9817,6 @@ void CodeStubAssembler::BranchIfNumberRelationalComparison(
 
       // Both {left} and {right} are Smi, so just perform a fast Smi comparison.
       switch (op) {
-        case Operation::kEqual:
-          BranchIfSmiEqual(smi_left, smi_right, if_true, if_false);
-          break;
         case Operation::kLessThan:
           BranchIfSmiLessThan(smi_left, smi_right, if_true, if_false);
           break;
@@ -9893,10 +9863,6 @@ void CodeStubAssembler::BranchIfNumberRelationalComparison(
   BIND(&do_float_comparison);
   {
     switch (op) {
-      case Operation::kEqual:
-        Branch(Float64Equal(var_left_float.value(), var_right_float.value()),
-               if_true, if_false);
-        break;
       case Operation::kLessThan:
         Branch(Float64LessThan(var_left_float.value(), var_right_float.value()),
                if_true, if_false);
@@ -11805,15 +11771,6 @@ Node* CodeStubAssembler::ArraySpeciesCreate(TNode<Context> context,
                      len);
 }
 
-Node* CodeStubAssembler::InternalArrayCreate(TNode<Context> context,
-                                             TNode<Number> len) {
-  Node* native_context = LoadNativeContext(context);
-  Node* const constructor = LoadContextElement(
-      native_context, Context::INTERNAL_ARRAY_FUNCTION_INDEX);
-  return ConstructJS(CodeFactory::Construct(isolate()), context, constructor,
-                     len);
-}
-
 Node* CodeStubAssembler::IsDetachedBuffer(Node* buffer) {
   CSA_ASSERT(this, HasInstanceType(buffer, JS_ARRAY_BUFFER_TYPE));
 

src/code-stub-assembler.h

@@ -1179,19 +1179,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
       Node* object, Node* index, Node* value,
       ParameterMode parameter_mode = INTPTR_PARAMETERS);
 
-  Node* StoreFixedDoubleArrayElementSmi(TNode<FixedDoubleArray> object,
-                                        TNode<Smi> index,
-                                        TNode<Float64T> value) {
-    return StoreFixedDoubleArrayElement(object, index, value, SMI_PARAMETERS);
-  }
-
-  void StoreFixedDoubleArrayHole(TNode<FixedDoubleArray> array, Node* index,
-                                 ParameterMode mode = INTPTR_PARAMETERS);
-  void StoreFixedDoubleArrayHoleSmi(TNode<FixedDoubleArray> array,
-                                    TNode<Smi> index) {
-    StoreFixedDoubleArrayHole(array, index, SMI_PARAMETERS);
-  }
-
   Node* StoreFeedbackVectorSlot(
       Node* object, Node* index, Node* value,
       WriteBarrierMode barrier_mode = UPDATE_WRITE_BARRIER,
@@ -1410,7 +1397,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
 
   Node* ArraySpeciesCreate(TNode<Context> context, TNode<Object> originalArray,
                            TNode<Number> len);
-  Node* InternalArrayCreate(TNode<Context> context, TNode<Number> len);
 
   void FillFixedArrayWithValue(ElementsKind kind, Node* array, Node* from_index,
                                Node* to_index,
@@ -1480,10 +1466,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
     return UncheckedCast<FixedDoubleArray>(base);
   }
 
-  TNode<Int32T> ConvertElementsKindToInt(TNode<Int32T> elements_kind) {
-    return UncheckedCast<Int32T>(elements_kind);
-  }
-
   enum class ExtractFixedArrayFlag {
     kFixedArrays = 1,
     kFixedDoubleArrays = 2,
@@ -1517,27 +1499,20 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // passed as the |source| parameter.
   // * |parameter_mode| determines the parameter mode of |first|, |count| and
   // |capacity|.
-  TNode<FixedArrayBase> ExtractFixedArray(
+  TNode<FixedArray> ExtractFixedArray(
       Node* source, Node* first, Node* count = nullptr,
       Node* capacity = nullptr,
       ExtractFixedArrayFlags extract_flags =
           ExtractFixedArrayFlag::kAllFixedArrays,
       ParameterMode parameter_mode = INTPTR_PARAMETERS);
 
-  TNode<FixedArray> ExtractFixedArray(TNode<FixedArray> source,
-                                      TNode<Smi> first, TNode<Smi> count,
-                                      TNode<Smi> capacity) {
-    return CAST(ExtractFixedArray(source, first, count, capacity,
-                                  ExtractFixedArrayFlag::kFixedArrays,
-                                  SMI_PARAMETERS));
-  }
-
-  TNode<FixedDoubleArray> ExtractFixedArray(TNode<FixedDoubleArray> source,
-                                            TNode<Smi> first, TNode<Smi> count,
-                                            TNode<Smi> capacity) {
-    return CAST(ExtractFixedArray(source, first, count, capacity,
-                                  ExtractFixedArrayFlag::kFixedDoubleArrays,
-                                  SMI_PARAMETERS));
+  TNode<FixedArray> ExtractFixedArray(
+      TNode<FixedArray> source, TNode<Smi> first, TNode<Smi> count,
+      TNode<Smi> capacity,
+      ExtractFixedArrayFlags extract_flags =
+          ExtractFixedArrayFlag::kAllFixedArrays) {
+    return ExtractFixedArray(source, first, count, capacity, extract_flags,
+                             SMI_PARAMETERS);
   }
 
   // Copy the entire contents of a FixedArray or FixedDoubleArray to a new
@@ -2501,12 +2476,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                               ElementsKind to_kind, bool is_jsarray,
                               Label* bailout);
 
-  void TransitionElementsKind(TNode<JSReceiver> object, TNode<Map> map,
-                              ElementsKind from_kind, ElementsKind to_kind,
-                              Label* bailout) {
-    TransitionElementsKind(object, map, from_kind, to_kind, true, bailout);
-  }
-
   void TrapAllocationMemento(Node* object, Label* memento_found);
 
   TNode<IntPtrT> PageFromAddress(TNode<IntPtrT> address);
@@ -2598,32 +2567,26 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   void BranchIfNumberRelationalComparison(Operation op, Node* left, Node* right,
                                           Label* if_true, Label* if_false);
 
-  void BranchIfNumberEqual(TNode<Number> left, TNode<Number> right,
-                           Label* if_true, Label* if_false) {
-    BranchIfNumberRelationalComparison(Operation::kEqual, left, right, if_true,
-                                       if_false);
-  }
-
-  void BranchIfNumberLessThan(TNode<Number> left, TNode<Number> right,
-                              Label* if_true, Label* if_false) {
+  void BranchIfNumberLessThan(Node* left, Node* right, Label* if_true,
+                              Label* if_false) {
     BranchIfNumberRelationalComparison(Operation::kLessThan, left, right,
                                        if_true, if_false);
   }
 
-  void BranchIfNumberLessThanOrEqual(TNode<Number> left, TNode<Number> right,
-                                     Label* if_true, Label* if_false) {
+  void BranchIfNumberLessThanOrEqual(Node* left, Node* right, Label* if_true,
+                                     Label* if_false) {
     BranchIfNumberRelationalComparison(Operation::kLessThanOrEqual, left, right,
                                        if_true, if_false);
   }
 
-  void BranchIfNumberGreaterThan(TNode<Number> left, TNode<Number> right,
-                                 Label* if_true, Label* if_false) {
+  void BranchIfNumberGreaterThan(Node* left, Node* right, Label* if_true,
+                                 Label* if_false) {
     BranchIfNumberRelationalComparison(Operation::kGreaterThan, left, right,
                                        if_true, if_false);
   }
 
-  void BranchIfNumberGreaterThanOrEqual(TNode<Number> left, TNode<Number> right,
-                                        Label* if_true, Label* if_false) {
+  void BranchIfNumberGreaterThanOrEqual(Node* left, Node* right, Label* if_true,
+                                        Label* if_false) {
     BranchIfNumberRelationalComparison(Operation::kGreaterThanOrEqual, left,
                                        right, if_true, if_false);
   }

src/contexts.h

@@ -72,6 +72,7 @@ enum ContextLookupFlags {
 
 #define NATIVE_CONTEXT_IMPORTED_FIELDS(V)                                      \
   V(ARRAY_SHIFT_INDEX, JSFunction, array_shift)                                \
+  V(ARRAY_SPLICE_INDEX, JSFunction, array_splice)                              \
   V(ARRAY_UNSHIFT_INDEX, JSFunction, array_unshift)                            \
   V(ARRAY_ENTRIES_ITERATOR_INDEX, JSFunction, array_entries_iterator)          \
   V(ARRAY_FOR_EACH_ITERATOR_INDEX, JSFunction, array_for_each_iterator)        \

src/flag-definitions.h

@@ -870,6 +870,8 @@ DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
 DEFINE_BOOL(builtins_in_stack_traces, false,
             "show built-in functions in stack traces")
+DEFINE_BOOL(enable_experimental_builtins, false,
+            "enable new csa-based experimental builtins")
 DEFINE_BOOL(disallow_code_generation_from_strings, false,
             "disallow eval and friends")
 DEFINE_BOOL(expose_async_hooks, false, "expose async_hooks object")

src/js/array.js

@@ -200,6 +200,35 @@ function ConvertToString(use_locale, x, locales, options) {
   return TO_STRING(x);
 }
 
+
+// This function implements the optimized splice implementation that can use
+// special array operations to handle sparse arrays in a sensible fashion.
+function SparseSlice(array, start_i, del_count, len, deleted_elements) {
+  // Move deleted elements to a new array (the return value from splice).
+  var indices = %GetArrayKeys(array, start_i + del_count);
+  if (IS_NUMBER(indices)) {
+    var limit = indices;
+    for (var i = start_i; i < limit; ++i) {
+      var current = array[i];
+      if (!IS_UNDEFINED(current) || i in array) {
+        %CreateDataProperty(deleted_elements, i - start_i, current);
+      }
+    }
+  } else {
+    var length = indices.length;
+    for (var k = 0; k < length; ++k) {
+      var key = indices[k];
+      if (key >= start_i) {
+        var current = array[key];
+        if (!IS_UNDEFINED(current) || key in array) {
+          %CreateDataProperty(deleted_elements, key - start_i, current);
+        }
+      }
+    }
+  }
+}
+
+
 // This function implements the optimized splice implementation that can use
 // special array operations to handle sparse arrays in a sensible fashion.
 function SparseMove(array, start_i, del_count, len, num_additional_args) {
@@ -536,6 +565,83 @@ function ArraySliceFallback(start, end) {
   return null;
 }
 
+function ComputeSpliceStartIndex(start_i, len) {
+  if (start_i < 0) {
+    start_i += len;
+    return start_i < 0 ? 0 : start_i;
+  }
+
+  return start_i > len ? len : start_i;
+}
+
+
+function ComputeSpliceDeleteCount(delete_count, num_arguments, len, start_i) {
+  // SpiderMonkey, TraceMonkey and JSC treat the case where no delete count is
+  // given as a request to delete all the elements from the start.
+  // And it differs from the case of undefined delete count.
+  // This does not follow ECMA-262, but we do the same for
+  // compatibility.
+  var del_count = 0;
+  if (num_arguments == 1)
+    return len - start_i;
+
+  del_count = TO_INTEGER(delete_count);
+  if (del_count < 0)
+    return 0;
+
+  if (del_count > len - start_i)
+    return len - start_i;
+
+  return del_count;
+}
+
+
+function ArraySpliceFallback(start, delete_count) {
+  var num_arguments = arguments.length;
+  var array = TO_OBJECT(this);
+  var len = TO_LENGTH(array.length);
+  var start_i = ComputeSpliceStartIndex(TO_INTEGER(start), len);
+  var del_count = ComputeSpliceDeleteCount(delete_count, num_arguments, len,
+                                           start_i);
+  var num_elements_to_add = num_arguments > 2 ? num_arguments - 2 : 0;
+
+  const new_len = len - del_count + num_elements_to_add;
+  if (new_len >= 2**53) throw %make_type_error(kInvalidArrayLength);
+
+  var deleted_elements = ArraySpeciesCreate(array, del_count);
+  deleted_elements.length = del_count;
+
+  var changed_elements = del_count;
+  if (num_elements_to_add != del_count) {
+    // If the slice needs to do a actually move elements after the insertion
+    // point, then include those in the estimate of changed elements.
+    changed_elements += len - start_i - del_count;
+  }
+  if (UseSparseVariant(array, len, IS_ARRAY(array), changed_elements)) {
+    %NormalizeElements(array);
+    if (IS_ARRAY(deleted_elements)) %NormalizeElements(deleted_elements);
+    SparseSlice(array, start_i, del_count, len, deleted_elements);
+    SparseMove(array, start_i, del_count, len, num_elements_to_add);
+  } else {
+    SimpleSlice(array, start_i, del_count, len, deleted_elements);
+    SimpleMove(array, start_i, del_count, len, num_elements_to_add);
+  }
+
+  // Insert the arguments into the resulting array in
+  // place of the deleted elements.
+  var i = start_i;
+  var arguments_index = 2;
+  var arguments_length = arguments.length;
+  while (arguments_index < arguments_length) {
+    array[i++] = arguments[arguments_index++];
+  }
+  array.length = new_len;
+
+  // Return the deleted elements.
+  return deleted_elements;
+}
+
+
 function InnerArraySort(array, length, comparefn) {
   // In-place QuickSort algorithm.
   // For short (length <= 10) arrays, insertion sort is used for efficiency.
@@ -892,6 +998,7 @@ utils.Export(function(to) {
   "array_values_iterator", ArrayValues,
   // Fallback implementations of Array builtins.
   "array_shift", ArrayShiftFallback,
+  "array_splice", ArraySpliceFallback,
   "array_unshift", ArrayUnshiftFallback,
 ]);
 

src/runtime/runtime-array.cc

@@ -30,16 +30,6 @@ RUNTIME_FUNCTION(Runtime_TransitionElementsKind) {
   return *object;
 }
 
-RUNTIME_FUNCTION(Runtime_TransitionElementsKindWithKind) {
-  HandleScope scope(isolate);
-  DCHECK_EQ(2, args.length());
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Smi, elements_kind_smi, 1);
-  ElementsKind to_kind = static_cast<ElementsKind>(elements_kind_smi->value());
-  JSObject::TransitionElementsKind(object, to_kind);
-  return *object;
-}
-
 namespace {
 // Find the next free position. undefined and holes are both considered
 // free spots. Returns "Nothing" if an exception occurred.

src/runtime/runtime.h

@@ -36,22 +36,21 @@ namespace internal {
 // A variable number of arguments is specified by a -1, additional restrictions
 // are specified by inline comments
 
-#define FOR_EACH_INTRINSIC_ARRAY(F)       \
-  F(ArrayIncludes_Slow, 3, 1)             \
-  F(ArrayIndexOf, 3, 1)                   \
-  F(ArrayIsArray, 1, 1)                   \
-  F(ArraySpeciesConstructor, 1, 1)        \
-  F(EstimateNumberOfElements, 1, 1)       \
-  F(GetArrayKeys, 2, 1)                   \
-  F(GrowArrayElements, 2, 1)              \
-  F(HasComplexElements, 1, 1)             \
-  F(IsArray, 1, 1)                        \
-  F(MoveArrayContents, 2, 1)              \
-  F(NewArray, -1 /* >= 3 */, 1)           \
-  F(NormalizeElements, 1, 1)              \
-  F(PrepareElementsForSort, 2, 1)         \
-  F(TransitionElementsKind, 2, 1)         \
-  F(TransitionElementsKindWithKind, 2, 1) \
+#define FOR_EACH_INTRINSIC_ARRAY(F) \
+  F(ArrayIncludes_Slow, 3, 1)       \
+  F(ArrayIndexOf, 3, 1)             \
+  F(ArrayIsArray, 1, 1)             \
+  F(ArraySpeciesConstructor, 1, 1)  \
+  F(EstimateNumberOfElements, 1, 1) \
+  F(GetArrayKeys, 2, 1)             \
+  F(GrowArrayElements, 2, 1)        \
+  F(HasComplexElements, 1, 1)       \
+  F(IsArray, 1, 1)                  \
+  F(MoveArrayContents, 2, 1)        \
+  F(NewArray, -1 /* >= 3 */, 1)     \
+  F(NormalizeElements, 1, 1)        \
+  F(PrepareElementsForSort, 2, 1)   \
+  F(TransitionElementsKind, 2, 1)   \
   F(TrySliceSimpleNonFastElements, 3, 1)
 
 #define FOR_EACH_INTRINSIC_ATOMICS(F)  \

test/test262/test262.status

@@ -474,6 +474,9 @@
   # https://bugs.chromium.org/p/v8/issues/detail?id=7993
   'intl402/RelativeTimeFormat/prototype/toStringTag/toStringTag': [FAIL],
 
+  # https://bugs.chromium.org/p/v8/issues/detail?id=7814
+  'built-ins/Array/prototype/splice/property-traps-order-with-species': [FAIL],
+
   # https://bugs.chromium.org/p/v8/issues/detail?id=6705
   'built-ins/Object/assign/strings-and-symbol-order': [FAIL],
 
@@ -515,6 +518,8 @@
   # https://bugs.chromium.org/p/v8/issues/detail?id=6538
   'built-ins/Array/prototype/unshift/throws-if-integer-limit-exceeded': [SKIP],
   'built-ins/Array/prototype/reverse/length-exceeding-integer-limit-with-proxy': [FAIL],
+  'built-ins/Array/prototype/splice/create-species-length-exceeding-integer-limit': [FAIL],
+  'built-ins/Array/prototype/splice/throws-if-integer-limit-exceeded': [SKIP],
 
   # https://bugs.chromium.org/p/v8/issues/detail?id=6541
   'language/export/escaped-as-export-specifier': [FAIL],