[CSA][cleanup] Turn {} allocation sites into base::nullopt

Bug: v8:10506
Change-Id: I171a587176f4a1a3c98d407e8b6a3b63bbf1ad6a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2202993
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67852}

src/builtins/builtins-array-gen.cc

@@ -476,7 +476,7 @@ TF_BUILTIN(CloneFastJSArrayFillingHoles, ArrayBuiltinsAssembler) {
                           LoadElementsKind(array))),
                       Word32BinaryNot(IsNoElementsProtectorCellInvalid())));
 
-  Return(CloneFastJSArray(context, array, {},
+  Return(CloneFastJSArray(context, array, base::nullopt,
                           HoleConversionMode::kConvertToUndefined));
 }
 
@@ -1664,7 +1664,8 @@ void ArrayBuiltinsAssembler::TailCallArrayConstructorStub(
 
 void ArrayBuiltinsAssembler::CreateArrayDispatchNoArgument(
     TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
-    AllocationSiteOverrideMode mode, TNode<AllocationSite> allocation_site) {
+    AllocationSiteOverrideMode mode,
+    base::Optional<TNode<AllocationSite>> allocation_site) {
   if (mode == DISABLE_ALLOCATION_SITES) {
     Callable callable = CodeFactory::ArrayNoArgumentConstructor(
         isolate(), GetInitialFastElementsKind(), mode);
@@ -1673,7 +1674,8 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchNoArgument(
                                  argc);
   } else {
     DCHECK_EQ(mode, DONT_OVERRIDE);
-    TNode<Int32T> elements_kind = LoadElementsKind(allocation_site);
+    DCHECK(allocation_site);
+    TNode<Int32T> elements_kind = LoadElementsKind(*allocation_site);
 
     // TODO(ishell): Compute the builtin index dynamically instead of
     // iterating over all expected elements kinds.
@@ -1687,7 +1689,7 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchNoArgument(
       Callable callable =
           CodeFactory::ArrayNoArgumentConstructor(isolate(), kind, mode);
 
-      TailCallArrayConstructorStub(callable, context, target, allocation_site,
+      TailCallArrayConstructorStub(callable, context, target, *allocation_site,
                                    argc);
 
       BIND(&next);
@@ -1700,7 +1702,8 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchNoArgument(
 
 void ArrayBuiltinsAssembler::CreateArrayDispatchSingleArgument(
     TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
-    AllocationSiteOverrideMode mode, TNode<AllocationSite> allocation_site) {
+    AllocationSiteOverrideMode mode,
+    base::Optional<TNode<AllocationSite>> allocation_site) {
   if (mode == DISABLE_ALLOCATION_SITES) {
     ElementsKind initial = GetInitialFastElementsKind();
     ElementsKind holey_initial = GetHoleyElementsKind(initial);
@@ -1711,7 +1714,8 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchSingleArgument(
                                  argc);
   } else {
     DCHECK_EQ(mode, DONT_OVERRIDE);
-    TNode<Smi> transition_info = LoadTransitionInfo(allocation_site);
+    DCHECK(allocation_site);
+    TNode<Smi> transition_info = LoadTransitionInfo(*allocation_site);
 
     // Least significant bit in fast array elements kind means holeyness.
     STATIC_ASSERT(PACKED_SMI_ELEMENTS == 0);
@@ -1734,7 +1738,7 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchSingleArgument(
       // Make elements kind holey and update elements kind in the type info.
       var_elements_kind = Word32Or(var_elements_kind.value(), Int32Constant(1));
       StoreObjectFieldNoWriteBarrier(
-          allocation_site, AllocationSite::kTransitionInfoOrBoilerplateOffset,
+          *allocation_site, AllocationSite::kTransitionInfoOrBoilerplateOffset,
           SmiOr(transition_info, SmiConstant(fast_elements_kind_holey_mask)));
       Goto(&normal_sequence);
     }
@@ -1755,7 +1759,7 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchSingleArgument(
       Callable callable =
           CodeFactory::ArraySingleArgumentConstructor(isolate(), kind, mode);
 
-      TailCallArrayConstructorStub(callable, context, target, allocation_site,
+      TailCallArrayConstructorStub(callable, context, target, *allocation_site,
                                    argc);
 
       BIND(&next);
@@ -1768,7 +1772,8 @@ void ArrayBuiltinsAssembler::CreateArrayDispatchSingleArgument(
 
 void ArrayBuiltinsAssembler::GenerateDispatchToArrayStub(
     TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
-    AllocationSiteOverrideMode mode, TNode<AllocationSite> allocation_site) {
+    AllocationSiteOverrideMode mode,
+    base::Optional<TNode<AllocationSite>> allocation_site) {
   Label check_one_case(this), fallthrough(this);
   GotoIfNot(Word32Equal(argc, Int32Constant(0)), &check_one_case);
   CreateArrayDispatchNoArgument(context, target, argc, mode, allocation_site);
@@ -1861,7 +1866,8 @@ void ArrayBuiltinsAssembler::GenerateConstructor(
     {
       TNode<JSArray> array = AllocateJSArray(
           elements_kind, array_map, array_size_smi, array_size_smi,
-          mode == DONT_TRACK_ALLOCATION_SITE ? TNode<AllocationSite>()
+          mode == DONT_TRACK_ALLOCATION_SITE
+              ? base::Optional<TNode<AllocationSite>>(base::nullopt)
               : CAST(allocation_site));
       Return(array);
     }
@@ -1881,9 +1887,10 @@ void ArrayBuiltinsAssembler::GenerateArrayNoArgumentConstructor(
       Parameter(Descriptor::kFunction), JSFunction::kContextOffset));
   bool track_allocation_site =
       AllocationSite::ShouldTrack(kind) && mode != DISABLE_ALLOCATION_SITES;
-  TNode<AllocationSite> allocation_site =
-      track_allocation_site ? CAST(Parameter(Descriptor::kAllocationSite))
-                            : TNode<AllocationSite>();
+  base::Optional<TNode<AllocationSite>> allocation_site =
+      track_allocation_site
+          ? CAST(Parameter(Descriptor::kAllocationSite))
+          : base::Optional<TNode<AllocationSite>>(base::nullopt);
   TNode<Map> array_map = LoadJSArrayElementsMap(kind, native_context);
   TNode<JSArray> array = AllocateJSArray(
       kind, array_map, IntPtrConstant(JSArray::kPreallocatedArrayElements),

src/builtins/builtins-array-gen.h

@@ -72,20 +72,20 @@ class ArrayBuiltinsAssembler : public CodeStubAssembler {
       TNode<JSFunction> target, TNode<HeapObject> allocation_site_or_undefined,
       TNode<Int32T> argc);
 
-  void GenerateDispatchToArrayStub(TNode<Context> context,
-                                   TNode<JSFunction> target, TNode<Int32T> argc,
+  void GenerateDispatchToArrayStub(
+      TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
       AllocationSiteOverrideMode mode,
-                                   TNode<AllocationSite> allocation_site = {});
+      base::Optional<TNode<AllocationSite>> allocation_site = base::nullopt);
 
   void CreateArrayDispatchNoArgument(
       TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
       AllocationSiteOverrideMode mode,
-      TNode<AllocationSite> allocation_site = {});
+      base::Optional<TNode<AllocationSite>> allocation_site);
 
   void CreateArrayDispatchSingleArgument(
       TNode<Context> context, TNode<JSFunction> target, TNode<Int32T> argc,
       AllocationSiteOverrideMode mode,
-      TNode<AllocationSite> allocation_site = {});
+      base::Optional<TNode<AllocationSite>> allocation_site);
 
   void GenerateConstructor(TNode<Context> context,
                            TNode<HeapObject> array_function,

src/builtins/builtins-object-gen.cc

@@ -314,7 +314,8 @@ TNode<JSArray> ObjectEntriesValuesBuiltinsAssembler::FastGetOwnValuesOrEntries(
         TNode<JSArray> array;
         TNode<FixedArrayBase> elements;
         std::tie(array, elements) = AllocateUninitializedJSArrayWithElements(
-            PACKED_ELEMENTS, array_map, SmiConstant(2), {}, IntPtrConstant(2));
+            PACKED_ELEMENTS, array_map, SmiConstant(2), base::nullopt,
+            IntPtrConstant(2));
         StoreFixedArrayElement(CAST(elements), 0, next_key, SKIP_WRITE_BARRIER);
         StoreFixedArrayElement(CAST(elements), 1, value, SKIP_WRITE_BARRIER);
         value = TNode<JSArray>::UncheckedCast(array);
@@ -499,7 +500,7 @@ TF_BUILTIN(ObjectKeys, ObjectBuiltinsAssembler) {
         LoadJSArrayElementsMap(PACKED_ELEMENTS, native_context);
     TNode<Smi> array_length = SmiTag(Signed(object_enum_length));
     std::tie(array, elements) = AllocateUninitializedJSArrayWithElements(
-        PACKED_ELEMENTS, array_map, array_length, {},
+        PACKED_ELEMENTS, array_map, array_length, base::nullopt,
         Signed(object_enum_length));
     CopyFixedArrayElements(PACKED_ELEMENTS, object_enum_keys, elements,
                            object_enum_length, SKIP_WRITE_BARRIER);
@@ -595,7 +596,7 @@ TF_BUILTIN(ObjectGetOwnPropertyNames, ObjectBuiltinsAssembler) {
     TNode<JSArray> array;
     TNode<FixedArrayBase> elements;
     std::tie(array, elements) = AllocateUninitializedJSArrayWithElements(
-        PACKED_ELEMENTS, array_map, array_length, {},
+        PACKED_ELEMENTS, array_map, array_length, base::nullopt,
         Signed(object_enum_length));
     CopyFixedArrayElements(PACKED_ELEMENTS, object_enum_keys, elements,
                            object_enum_length, SKIP_WRITE_BARRIER);

src/builtins/builtins-regexp-gen.cc

@@ -89,7 +89,7 @@ TNode<JSRegExpResult> RegExpBuiltinsAssembler::AllocateRegExpResult(
   const ElementsKind elements_kind = PACKED_ELEMENTS;
   TNode<Map> map = CAST(LoadContextElement(LoadNativeContext(context),
                                            Context::REGEXP_RESULT_MAP_INDEX));
-  TNode<AllocationSite> no_allocation_site = {};
+  base::Optional<TNode<AllocationSite>> no_allocation_site = base::nullopt;
   TNode<IntPtrT> length_intptr = SmiUntag(length);
 
   // Note: The returned `elements` may be in young large object space, but
@@ -1356,7 +1356,6 @@ TNode<JSArray> RegExpBuiltinsAssembler::RegExpPrototypeSplitBody(
   const ElementsKind kind = PACKED_ELEMENTS;
   const ParameterMode mode = CodeStubAssembler::INTPTR_PARAMETERS;
 
-  TNode<AllocationSite> allocation_site = {};
   const TNode<NativeContext> native_context = LoadNativeContext(context);
   TNode<Map> array_map = LoadJSArrayElementsMap(kind, native_context);
 
@@ -1396,6 +1395,7 @@ TNode<JSArray> RegExpBuiltinsAssembler::RegExpPrototypeSplitBody(
       {
         TNode<Smi> length = SmiConstant(1);
         TNode<IntPtrT> capacity = IntPtrConstant(1);
+        base::Optional<TNode<AllocationSite>> allocation_site = base::nullopt;
         var_result =
             AllocateJSArray(kind, array_map, capacity, length, allocation_site);
 
@@ -1570,6 +1570,7 @@ TNode<JSArray> RegExpBuiltinsAssembler::RegExpPrototypeSplitBody(
   {
     TNode<Smi> length = SmiZero();
     TNode<IntPtrT> capacity = IntPtrZero();
+    base::Optional<TNode<AllocationSite>> allocation_site = base::nullopt;
     var_result =
         AllocateJSArray(kind, array_map, capacity, length, allocation_site);
     Goto(&done);

src/codegen/code-stub-assembler.cc

@@ -3552,12 +3552,13 @@ TNode<BoolT> CodeStubAssembler::IsValidFastJSArrayCapacity(
 
 TNode<JSArray> CodeStubAssembler::AllocateJSArray(
     TNode<Map> array_map, TNode<FixedArrayBase> elements, TNode<Smi> length,
-    TNode<AllocationSite> allocation_site, int array_header_size) {
+    base::Optional<TNode<AllocationSite>> allocation_site,
+    int array_header_size) {
   Comment("begin allocation of JSArray passing in elements");
   CSA_SLOW_ASSERT(this, TaggedIsPositiveSmi(length));
 
   int base_size = array_header_size;
-  if (!allocation_site.is_null()) {
+  if (allocation_site) {
     base_size += AllocationMemento::kSize;
   }
 
@@ -3571,8 +3572,9 @@ TNode<JSArray> CodeStubAssembler::AllocateJSArray(
 std::pair<TNode<JSArray>, TNode<FixedArrayBase>>
 CodeStubAssembler::AllocateUninitializedJSArrayWithElements(
     ElementsKind kind, TNode<Map> array_map, TNode<Smi> length,
-    TNode<AllocationSite> allocation_site, TNode<IntPtrT> capacity,
-    AllocationFlags allocation_flags, int array_header_size) {
+    base::Optional<TNode<AllocationSite>> allocation_site,
+    TNode<IntPtrT> capacity, AllocationFlags allocation_flags,
+    int array_header_size) {
   Comment("begin allocation of JSArray with elements");
   CHECK_EQ(allocation_flags & ~kAllowLargeObjectAllocation, 0);
   CSA_SLOW_ASSERT(this, TaggedIsPositiveSmi(length));
@@ -3608,7 +3610,7 @@ CodeStubAssembler::AllocateUninitializedJSArrayWithElements(
   BIND(&nonempty);
   {
     int base_size = array_header_size;
-    if (!allocation_site.is_null()) {
+    if (allocation_site) {
       base_size += AllocationMemento::kSize;
     }
 
@@ -3680,7 +3682,8 @@ CodeStubAssembler::AllocateUninitializedJSArrayWithElements(
 
 TNode<JSArray> CodeStubAssembler::AllocateUninitializedJSArray(
     TNode<Map> array_map, TNode<Smi> length,
-    TNode<AllocationSite> allocation_site, TNode<IntPtrT> size_in_bytes) {
+    base::Optional<TNode<AllocationSite>> allocation_site,
+    TNode<IntPtrT> size_in_bytes) {
   CSA_SLOW_ASSERT(this, TaggedIsPositiveSmi(length));
 
   // Allocate space for the JSArray and the elements FixedArray in one go.
@@ -3691,9 +3694,9 @@ TNode<JSArray> CodeStubAssembler::AllocateUninitializedJSArray(
   StoreObjectFieldRoot(array, JSArray::kPropertiesOrHashOffset,
                        RootIndex::kEmptyFixedArray);
 
-  if (!allocation_site.is_null()) {
+  if (allocation_site) {
     InitializeAllocationMemento(array, IntPtrConstant(JSArray::kHeaderSize),
-                                allocation_site);
+                                *allocation_site);
   }
 
   return CAST(array);
@@ -3701,7 +3704,7 @@ TNode<JSArray> CodeStubAssembler::AllocateUninitializedJSArray(
 
 TNode<JSArray> CodeStubAssembler::AllocateJSArray(
     ElementsKind kind, TNode<Map> array_map, TNode<IntPtrT> capacity,
-    TNode<Smi> length, TNode<AllocationSite> allocation_site,
+    TNode<Smi> length, base::Optional<TNode<AllocationSite>> allocation_site,
     AllocationFlags allocation_flags) {
   CSA_SLOW_ASSERT(this, TaggedIsPositiveSmi(length));
 
@@ -3743,14 +3746,15 @@ TNode<JSArray> CodeStubAssembler::ExtractFastJSArray(TNode<Context> context,
       LoadElements(array), begin, count, base::nullopt,
       ExtractFixedArrayFlag::kAllFixedArrays, nullptr, elements_kind);
 
-  TNode<JSArray> result =
-      AllocateJSArray(array_map, new_elements, ParameterToTagged(count), {});
+  TNode<JSArray> result = AllocateJSArray(
+      array_map, new_elements, ParameterToTagged(count), base::nullopt);
   return result;
 }
 
 TNode<JSArray> CodeStubAssembler::CloneFastJSArray(
     TNode<Context> context, TNode<JSArray> array,
-    TNode<AllocationSite> allocation_site, HoleConversionMode convert_holes) {
+    base::Optional<TNode<AllocationSite>> allocation_site,
+    HoleConversionMode convert_holes) {
   // TODO(dhai): we should be able to assert IsFastJSArray(array) here, but this
   // function is also used to copy boilerplates even when the no-elements
   // protector is invalid. This function should be renamed to reflect its uses.

src/codegen/code-stub-assembler.h

@@ -1968,18 +1968,18 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   std::pair<TNode<JSArray>, TNode<FixedArrayBase>>
   AllocateUninitializedJSArrayWithElements(
       ElementsKind kind, TNode<Map> array_map, TNode<Smi> length,
-      TNode<AllocationSite> allocation_site, TNode<IntPtrT> capacity,
-      AllocationFlags allocation_flags = kNone,
+      base::Optional<TNode<AllocationSite>> allocation_site,
+      TNode<IntPtrT> capacity, AllocationFlags allocation_flags = kNone,
       int array_header_size = JSArray::kHeaderSize);
 
   // Allocate a JSArray and fill elements with the hole.
-  TNode<JSArray> AllocateJSArray(ElementsKind kind, TNode<Map> array_map,
-                                 TNode<IntPtrT> capacity, TNode<Smi> length,
-                                 TNode<AllocationSite> allocation_site,
+  TNode<JSArray> AllocateJSArray(
+      ElementsKind kind, TNode<Map> array_map, TNode<IntPtrT> capacity,
+      TNode<Smi> length, base::Optional<TNode<AllocationSite>> allocation_site,
       AllocationFlags allocation_flags = kNone);
-  TNode<JSArray> AllocateJSArray(ElementsKind kind, TNode<Map> array_map,
-                                 TNode<Smi> capacity, TNode<Smi> length,
-                                 TNode<AllocationSite> allocation_site,
+  TNode<JSArray> AllocateJSArray(
+      ElementsKind kind, TNode<Map> array_map, TNode<Smi> capacity,
+      TNode<Smi> length, base::Optional<TNode<AllocationSite>> allocation_site,
       AllocationFlags allocation_flags = kNone) {
     return AllocateJSArray(kind, array_map, SmiUntag(capacity), length,
                            allocation_site, allocation_flags);
@@ -1987,21 +1987,20 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   TNode<JSArray> AllocateJSArray(ElementsKind kind, TNode<Map> array_map,
                                  TNode<Smi> capacity, TNode<Smi> length,
                                  AllocationFlags allocation_flags = kNone) {
-    return AllocateJSArray(kind, array_map, SmiUntag(capacity), length, {},
-                           allocation_flags);
+    return AllocateJSArray(kind, array_map, SmiUntag(capacity), length,
+                           base::nullopt, allocation_flags);
   }
   TNode<JSArray> AllocateJSArray(ElementsKind kind, TNode<Map> array_map,
                                  TNode<IntPtrT> capacity, TNode<Smi> length,
                                  AllocationFlags allocation_flags = kNone) {
-    return AllocateJSArray(kind, array_map, capacity, length, {},
+    return AllocateJSArray(kind, array_map, capacity, length, base::nullopt,
                            allocation_flags);
   }
 
   // Allocate a JSArray and initialize the header fields.
-  TNode<JSArray> AllocateJSArray(TNode<Map> array_map,
-                                 TNode<FixedArrayBase> elements,
-                                 TNode<Smi> length,
-                                 TNode<AllocationSite> allocation_site = {},
+  TNode<JSArray> AllocateJSArray(
+      TNode<Map> array_map, TNode<FixedArrayBase> elements, TNode<Smi> length,
+      base::Optional<TNode<AllocationSite>> allocation_site = base::nullopt,
       int array_header_size = JSArray::kHeaderSize);
 
   enum class HoleConversionMode { kDontConvert, kConvertToUndefined };
@@ -2017,7 +2016,7 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   // function generates significantly less code in this case.
   TNode<JSArray> CloneFastJSArray(
       TNode<Context> context, TNode<JSArray> array,
-      TNode<AllocationSite> allocation_site = {},
+      base::Optional<TNode<AllocationSite>> allocation_site = base::nullopt,
       HoleConversionMode convert_holes = HoleConversionMode::kDontConvert);
 
   TNode<JSArray> ExtractFastJSArray(TNode<Context> context,
@@ -3955,7 +3954,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   // fields initialized.
   TNode<JSArray> AllocateUninitializedJSArray(
       TNode<Map> array_map, TNode<Smi> length,
-      TNode<AllocationSite> allocation_site, TNode<IntPtrT> size_in_bytes);
+      base::Optional<TNode<AllocationSite>> allocation_site,
+      TNode<IntPtrT> size_in_bytes);
 
   TNode<BoolT> IsValidSmi(TNode<Smi> smi);