[factory] Dehandlify object initializers in factory

Clang cannot optimise across handle derefs and produces quite
inefficient code when setting multiple properties in a row.

We are already dealing with a lot of raw pointers in factory, thus
adding further DisallowGarbageCollection and will not significantly
increase the risk of stale pointers.

Bug: v8:11263
Change-Id: I2b62f79ecde95faa84a182c09d89c03423900d98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2581963
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73127}

src/heap/factory-inl.h

@@ -67,7 +67,9 @@ Handle<Object> Factory::NewURIError() {
                   MessageTemplate::kURIMalformed);
 }
 
-ReadOnlyRoots Factory::read_only_roots() { return ReadOnlyRoots(isolate()); }
+ReadOnlyRoots Factory::read_only_roots() const {
+  return ReadOnlyRoots(isolate());
+}
 
 }  // namespace internal
 }  // namespace v8

src/heap/factory.h

@@ -99,7 +99,7 @@ enum class NumberCacheMode { kIgnore, kSetOnly, kBoth };
 // Interface for handle based allocation.
 class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
  public:
-  inline ReadOnlyRoots read_only_roots();
+  inline ReadOnlyRoots read_only_roots() const;
 
   template <typename T>
   Handle<T> MakeHandle(T obj) {
@@ -915,7 +915,7 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   HeapObject AllocateRaw(int size, AllocationType allocation,
                          AllocationAlignment alignment = kWordAligned);
 
-  Isolate* isolate() {
+  Isolate* isolate() const {
     // Downcast to the privately inherited sub-class using c-style casts to
     // avoid undefined behavior (as static_cast cannot cast across private
     // bases).
@@ -936,10 +936,12 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
       Handle<Map> map, Handle<FixedArrayBase> elements,
       Handle<JSArrayBuffer> buffer, size_t byte_offset, size_t byte_length);
 
+  Symbol NewSymbolInternal(AllocationType allocation = AllocationType::kOld);
+
   // Allocates new context with given map, sets length and initializes the
   // after-header part with uninitialized values and leaves the context header
   // uninitialized.
-  Handle<Context> NewContext(Handle<Map> map, int size,
+  Context NewContextInternal(Handle<Map> map, int size,
                              int variadic_part_length,
                              AllocationType allocation);
 

src/objects/objects.cc

@@ -4303,7 +4303,7 @@ template Handle<DescriptorArray> DescriptorArray::Allocate(
     LocalIsolate* isolate, int nof_descriptors, int slack,
     AllocationType allocation);
 
-void DescriptorArray::Initialize(EnumCache enum_cache,
+void DescriptorArray::Initialize(EnumCache empty_enum_cache,
                                  HeapObject undefined_value,
                                  int nof_descriptors, int slack) {
   DCHECK_GE(nof_descriptors, 0);
@@ -4313,13 +4313,13 @@ void DescriptorArray::Initialize(EnumCache enum_cache,
   set_number_of_descriptors(nof_descriptors);
   set_raw_number_of_marked_descriptors(0);
   set_filler16bits(0);
-  set_enum_cache(enum_cache);
+  set_enum_cache(empty_enum_cache, SKIP_WRITE_BARRIER);
   MemsetTagged(GetDescriptorSlot(0), undefined_value,
                number_of_all_descriptors() * kEntrySize);
 }
 
 void DescriptorArray::ClearEnumCache() {
-  set_enum_cache(GetReadOnlyRoots().empty_enum_cache());
+  set_enum_cache(GetReadOnlyRoots().empty_enum_cache(), SKIP_WRITE_BARRIER);
 }
 
 void DescriptorArray::Replace(InternalIndex index, Descriptor* descriptor) {