Move some string allocation functions from Factory to FactoryBase

In a subsequent CL, I'll need to do String allocations in Turbofan (in
the background), where only a LocalFactory is available. By moving
those string allocation functions to FactoryBase, they will also be
available in the LocalFactory.

Change-Id: I066bbd4b5016645de183633ef237986e0ae50f5d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811581Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Darius Mercadier <dmercadier@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82262}

src/heap/factory-base-inl.h

@@ -16,6 +16,14 @@
 namespace v8 {
 namespace internal {
 
+#define ROOT_ACCESSOR(Type, name, CamelName)  \
+  template <typename Impl>                    \
+  Handle<Type> FactoryBase<Impl>::name() {    \
+    return read_only_roots().name##_handle(); \
+  }
+READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
 template <typename Impl>
 Handle<Oddball> FactoryBase<Impl>::ToBoolean(bool value) {
   return value ? impl()->true_value() : impl()->false_value();

src/heap/factory-base.cc

@@ -27,6 +27,7 @@
 #include "src/objects/string.h"
 #include "src/objects/swiss-name-dictionary-inl.h"
 #include "src/objects/template-objects-inl.h"
+#include "src/roots/roots.h"
 
 namespace v8 {
 namespace internal {
@@ -818,6 +819,144 @@ Handle<String> FactoryBase<Impl>::NewConsString(Handle<String> left,
   return handle(result, isolate());
 }
 
+template <typename Impl>
+Handle<String> FactoryBase<Impl>::LookupSingleCharacterStringFromCode(
+    uint16_t code) {
+  if (code <= unibrow::Latin1::kMaxChar) {
+    DisallowGarbageCollection no_gc;
+    Object value = single_character_string_table()->get(code);
+    DCHECK_NE(value, *undefined_value());
+    return handle(String::cast(value), isolate());
+  }
+  uint16_t buffer[] = {code};
+  return InternalizeString(base::Vector<const uint16_t>(buffer, 1));
+}
+
+template <typename Impl>
+MaybeHandle<String> FactoryBase<Impl>::NewStringFromOneByte(
+    const base::Vector<const uint8_t>& string, AllocationType allocation) {
+  DCHECK_NE(allocation, AllocationType::kReadOnly);
+  int length = string.length();
+  if (length == 0) return empty_string();
+  if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
+  Handle<SeqOneByteString> result;
+  ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
+                             NewRawOneByteString(string.length(), allocation),
+                             String);
+
+  DisallowGarbageCollection no_gc;
+  // Copy the characters into the new object.
+  // SharedStringAccessGuardIfNeeded is NotNeeded because {result} is freshly
+  // allocated and hasn't escaped the factory yet, so it can't be concurrently
+  // accessed.
+  CopyChars(SeqOneByteString::cast(*result).GetChars(
+                no_gc, SharedStringAccessGuardIfNeeded::NotNeeded()),
+            string.begin(), length);
+  return result;
+}
+namespace {
+
+template <typename Impl>
+V8_INLINE Handle<String> CharToString(FactoryBase<Impl>* factory,
+                                      const char* string,
+                                      NumberCacheMode mode) {
+  // We tenure the allocated string since it is referenced from the
+  // number-string cache which lives in the old space.
+  AllocationType type = mode == NumberCacheMode::kIgnore
+                            ? AllocationType::kYoung
+                            : AllocationType::kOld;
+  return factory->NewStringFromAsciiChecked(string, type);
+}
+
+}  // namespace
+
+template <typename Impl>
+Handle<String> FactoryBase<Impl>::NumberToString(Handle<Object> number,
+                                                 NumberCacheMode mode) {
+  SLOW_DCHECK(number->IsNumber());
+  if (number->IsSmi()) return SmiToString(Smi::cast(*number), mode);
+
+  double double_value = Handle<HeapNumber>::cast(number)->value();
+  // Try to canonicalize doubles.
+  int smi_value;
+  if (DoubleToSmiInteger(double_value, &smi_value)) {
+    return SmiToString(Smi::FromInt(smi_value), mode);
+  }
+  return HeapNumberToString(Handle<HeapNumber>::cast(number), double_value,
+                            mode);
+}
+
+template <typename Impl>
+Handle<String> FactoryBase<Impl>::HeapNumberToString(Handle<HeapNumber> number,
+                                                     double value,
+                                                     NumberCacheMode mode) {
+  int hash = mode == NumberCacheMode::kIgnore
+                 ? 0
+                 : impl()->NumberToStringCacheHash(value);
+
+  if (mode == NumberCacheMode::kBoth) {
+    Handle<Object> cached = impl()->NumberToStringCacheGet(*number, hash);
+    if (!cached->IsUndefined(isolate())) return Handle<String>::cast(cached);
+  }
+
+  Handle<String> result;
+  if (value == 0) {
+    result = zero_string();
+  } else if (std::isnan(value)) {
+    result = NaN_string();
+  } else {
+    char arr[kNumberToStringBufferSize];
+    base::Vector<char> buffer(arr, arraysize(arr));
+    const char* string = DoubleToCString(value, buffer);
+    result = CharToString(this, string, mode);
+  }
+  if (mode != NumberCacheMode::kIgnore) {
+    impl()->NumberToStringCacheSet(number, hash, result);
+  }
+  return result;
+}
+
+template <typename Impl>
+inline Handle<String> FactoryBase<Impl>::SmiToString(Smi number,
+                                                     NumberCacheMode mode) {
+  int hash = mode == NumberCacheMode::kIgnore
+                 ? 0
+                 : impl()->NumberToStringCacheHash(number);
+
+  if (mode == NumberCacheMode::kBoth) {
+    Handle<Object> cached = impl()->NumberToStringCacheGet(number, hash);
+    if (!cached->IsUndefined(isolate())) return Handle<String>::cast(cached);
+  }
+
+  Handle<String> result;
+  if (number == Smi::zero()) {
+    result = zero_string();
+  } else {
+    char arr[kNumberToStringBufferSize];
+    base::Vector<char> buffer(arr, arraysize(arr));
+    const char* string = IntToCString(number.value(), buffer);
+    result = CharToString(this, string, mode);
+  }
+  if (mode != NumberCacheMode::kIgnore) {
+    impl()->NumberToStringCacheSet(handle(number, isolate()), hash, result);
+  }
+
+  // Compute the hash here (rather than letting the caller take care of it) so
+  // that the "cache hit" case above doesn't have to bother with it.
+  static_assert(Smi::kMaxValue <= std::numeric_limits<uint32_t>::max());
+  {
+    DisallowGarbageCollection no_gc;
+    String raw = *result;
+    if (raw.raw_hash_field() == String::kEmptyHashField &&
+        number.value() >= 0) {
+      uint32_t raw_hash_field = StringHasher::MakeArrayIndexHash(
+          static_cast<uint32_t>(number.value()), raw.length());
+      raw.set_raw_hash_field(raw_hash_field);
+    }
+  }
+  return result;
+}
+
 template <typename Impl>
 Handle<FreshlyAllocatedBigInt> FactoryBase<Impl>::NewBigInt(
     int length, AllocationType allocation) {

src/heap/factory-base.h

@@ -47,6 +47,8 @@ class ValueType;
 template <typename Impl>
 class FactoryBase;
 
+enum class NumberCacheMode { kIgnore, kSetOnly, kBoth };
+
 // Putting Torque-generated definitions in a superclass allows to shadow them
 // easily when they shouldn't be used and to reference them when they happen to
 // have the same signature.
@@ -60,12 +62,15 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) TorqueGeneratedFactory {
 };
 
 template <typename Impl>
-class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
-    : public TorqueGeneratedFactory<Impl> {
+class FactoryBase : public TorqueGeneratedFactory<Impl> {
  public:
   // Converts the given boolean condition to JavaScript boolean value.
   inline Handle<Oddball> ToBoolean(bool value);
 
+#define ROOT_ACCESSOR(Type, name, CamelName) inline Handle<Type> name();
+  READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
   // Numbers (e.g. literals) are pretenured by the parser.
   // The return value may be a smi or a heap number.
   template <AllocationType allocation = AllocationType::kYoung>
@@ -221,6 +226,20 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
   Handle<SeqTwoByteString> AllocateRawTwoByteInternalizedString(
       int length, uint32_t raw_hash_field);
 
+  // Creates a single character string where the character has given code.
+  // A cache is used for Latin1 codes.
+  Handle<String> LookupSingleCharacterStringFromCode(uint16_t code);
+
+  MaybeHandle<String> NewStringFromOneByte(
+      const base::Vector<const uint8_t>& string,
+      AllocationType allocation = AllocationType::kYoung);
+
+  inline Handle<String> NewStringFromAsciiChecked(
+      const char* str, AllocationType allocation = AllocationType::kYoung) {
+    return NewStringFromOneByte(base::OneByteVector(str), allocation)
+        .ToHandleChecked();
+  }
+
   // Allocates and partially initializes an one-byte or two-byte String. The
   // characters of the string are uninitialized. Currently used in regexp code
   // only, where they are pretenured.
@@ -237,6 +256,14 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
       Handle<String> left, Handle<String> right, int length, bool one_byte,
       AllocationType allocation = AllocationType::kYoung);
 
+  V8_WARN_UNUSED_RESULT Handle<String> NumberToString(
+      Handle<Object> number, NumberCacheMode mode = NumberCacheMode::kBoth);
+  V8_WARN_UNUSED_RESULT Handle<String> HeapNumberToString(
+      Handle<HeapNumber> number, double value,
+      NumberCacheMode mode = NumberCacheMode::kBoth);
+  V8_WARN_UNUSED_RESULT Handle<String> SmiToString(
+      Smi number, NumberCacheMode mode = NumberCacheMode::kBoth);
+
   V8_WARN_UNUSED_RESULT MaybeHandle<SeqOneByteString> NewRawSharedOneByteString(
       int length);
   V8_WARN_UNUSED_RESULT MaybeHandle<SeqTwoByteString> NewRawSharedTwoByteString(
@@ -274,6 +301,9 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
       AllocationType allocation, Map string_map);
 
  protected:
+  // Must be large enough to fit any double, int, or size_t.
+  static constexpr int kNumberToStringBufferSize = 32;
+
   // Allocate memory for an uninitialized array (e.g., a FixedArray or similar).
   HeapObject AllocateRawArray(int size, AllocationType allocation);
   HeapObject AllocateRawFixedArray(int length, AllocationType allocation);
@@ -318,6 +348,11 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
   friend TorqueGeneratedFactory<Impl>;
 };
 
+extern template class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE)
+    FactoryBase<Factory>;
+extern template class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE)
+    FactoryBase<LocalFactory>;
+
 }  // namespace internal
 }  // namespace v8
 

src/heap/factory-inl.h

@@ -27,7 +27,7 @@ namespace internal {
   Handle<Type> Factory::name() {                                             \
     return Handle<Type>(&isolate()->roots_table()[RootIndex::k##CamelName]); \
   }
-ROOT_LIST(ROOT_ACCESSOR)
+MUTABLE_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
 bool Factory::CodeBuilder::CompiledWithConcurrentBaseline() const {
@@ -89,6 +89,35 @@ Factory::CodeBuilder& Factory::CodeBuilder::set_interpreter_data(
   return *this;
 }
 
+void Factory::NumberToStringCacheSet(Handle<Object> number, int hash,
+                                     Handle<String> js_string) {
+  if (!number_string_cache()->get(hash * 2).IsUndefined(isolate()) &&
+      !FLAG_optimize_for_size) {
+    int full_size = isolate()->heap()->MaxNumberToStringCacheSize();
+    if (number_string_cache()->length() != full_size) {
+      Handle<FixedArray> new_cache =
+          NewFixedArray(full_size, AllocationType::kOld);
+      isolate()->heap()->set_number_string_cache(*new_cache);
+      return;
+    }
+  }
+  DisallowGarbageCollection no_gc;
+  FixedArray cache = *number_string_cache();
+  cache.set(hash * 2, *number);
+  cache.set(hash * 2 + 1, *js_string);
+}
+
+Handle<Object> Factory::NumberToStringCacheGet(Object number, int hash) {
+  DisallowGarbageCollection no_gc;
+  FixedArray cache = *number_string_cache();
+  Object key = cache.get(hash * 2);
+  if (key == number || (key.IsHeapNumber() && number.IsHeapNumber() &&
+                        key.Number() == number.Number())) {
+    return Handle<String>(String::cast(cache.get(hash * 2 + 1)), isolate());
+  }
+  return undefined_value();
+}
+
 }  // namespace internal
 }  // namespace v8
 

src/heap/factory.cc

@@ -683,24 +683,6 @@ template Handle<String> Factory::InternalizeString(
     Handle<SeqTwoByteString> string, int from, int length,
     bool convert_encoding);
 
-MaybeHandle<String> Factory::NewStringFromOneByte(
-    const base::Vector<const uint8_t>& string, AllocationType allocation) {
-  DCHECK_NE(allocation, AllocationType::kReadOnly);
-  int length = string.length();
-  if (length == 0) return empty_string();
-  if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
-  Handle<SeqOneByteString> result;
-  ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
-                             NewRawOneByteString(string.length(), allocation),
-                             String);
-
-  DisallowGarbageCollection no_gc;
-  // Copy the characters into the new object.
-  CopyChars(SeqOneByteString::cast(*result).GetChars(no_gc), string.begin(),
-            length);
-  return result;
-}
-
 namespace {
 void ThrowInvalidEncodedStringBytes(Isolate* isolate, MessageTemplate message) {
 #if V8_ENABLE_WEBASSEMBLY
@@ -1058,17 +1040,6 @@ StringTransitionStrategy Factory::ComputeSharingStrategyForString(
   }
 }
 
-Handle<String> Factory::LookupSingleCharacterStringFromCode(uint16_t code) {
-  if (code <= unibrow::Latin1::kMaxChar) {
-    DisallowGarbageCollection no_gc;
-    Object value = single_character_string_table()->get(code);
-    DCHECK_NE(value, *undefined_value());
-    return handle(String::cast(value), isolate());
-  }
-  uint16_t buffer[] = {code};
-  return InternalizeString(base::Vector<const uint16_t>(buffer, 1));
-}
-
 Handle<String> Factory::NewSurrogatePairString(uint16_t lead, uint16_t trail) {
   DCHECK_GE(lead, 0xD800);
   DCHECK_LE(lead, 0xDBFF);
@@ -3376,141 +3347,17 @@ Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfoForWebSnapshot() {
                                FunctionKind::kNormalFunction);
 }
 
-namespace {
-V8_INLINE int NumberToStringCacheHash(Handle<FixedArray> cache, Smi number) {
-  int mask = (cache->length() >> 1) - 1;
+int Factory::NumberToStringCacheHash(Smi number) {
+  int mask = (number_string_cache()->length() >> 1) - 1;
   return number.value() & mask;
 }
 
-V8_INLINE int NumberToStringCacheHash(Handle<FixedArray> cache, double number) {
-  int mask = (cache->length() >> 1) - 1;
+int Factory::NumberToStringCacheHash(double number) {
+  int mask = (number_string_cache()->length() >> 1) - 1;
   int64_t bits = base::bit_cast<int64_t>(number);
   return (static_cast<int>(bits) ^ static_cast<int>(bits >> 32)) & mask;
 }
 
-V8_INLINE Handle<String> CharToString(Factory* factory, const char* string,
-                                      NumberCacheMode mode) {
-  // We tenure the allocated string since it is referenced from the
-  // number-string cache which lives in the old space.
-  AllocationType type = mode == NumberCacheMode::kIgnore
-                            ? AllocationType::kYoung
-                            : AllocationType::kOld;
-  return factory->NewStringFromAsciiChecked(string, type);
-}
-
-}  // namespace
-
-void Factory::NumberToStringCacheSet(Handle<Object> number, int hash,
-                                     Handle<String> js_string) {
-  if (!number_string_cache()->get(hash * 2).IsUndefined(isolate()) &&
-      !FLAG_optimize_for_size) {
-    int full_size = isolate()->heap()->MaxNumberToStringCacheSize();
-    if (number_string_cache()->length() != full_size) {
-      Handle<FixedArray> new_cache =
-          NewFixedArray(full_size, AllocationType::kOld);
-      isolate()->heap()->set_number_string_cache(*new_cache);
-      return;
-    }
-  }
-  DisallowGarbageCollection no_gc;
-  FixedArray cache = *number_string_cache();
-  cache.set(hash * 2, *number);
-  cache.set(hash * 2 + 1, *js_string);
-}
-
-Handle<Object> Factory::NumberToStringCacheGet(Object number, int hash) {
-  DisallowGarbageCollection no_gc;
-  FixedArray cache = *number_string_cache();
-  Object key = cache.get(hash * 2);
-  if (key == number || (key.IsHeapNumber() && number.IsHeapNumber() &&
-                        key.Number() == number.Number())) {
-    return Handle<String>(String::cast(cache.get(hash * 2 + 1)), isolate());
-  }
-  return undefined_value();
-}
-
-Handle<String> Factory::NumberToString(Handle<Object> number,
-                                       NumberCacheMode mode) {
-  SLOW_DCHECK(number->IsNumber());
-  if (number->IsSmi()) return SmiToString(Smi::cast(*number), mode);
-
-  double double_value = Handle<HeapNumber>::cast(number)->value();
-  // Try to canonicalize doubles.
-  int smi_value;
-  if (DoubleToSmiInteger(double_value, &smi_value)) {
-    return SmiToString(Smi::FromInt(smi_value), mode);
-  }
-  return HeapNumberToString(Handle<HeapNumber>::cast(number), double_value,
-                            mode);
-}
-
-// Must be large enough to fit any double, int, or size_t.
-static const int kNumberToStringBufferSize = 32;
-
-Handle<String> Factory::HeapNumberToString(Handle<HeapNumber> number,
-                                           double value, NumberCacheMode mode) {
-  int hash = 0;
-  if (mode != NumberCacheMode::kIgnore) {
-    hash = NumberToStringCacheHash(number_string_cache(), value);
-  }
-  if (mode == NumberCacheMode::kBoth) {
-    Handle<Object> cached = NumberToStringCacheGet(*number, hash);
-    if (!cached->IsUndefined(isolate())) return Handle<String>::cast(cached);
-  }
-
-  Handle<String> result;
-  if (value == 0) {
-    result = zero_string();
-  } else if (std::isnan(value)) {
-    result = NaN_string();
-  } else {
-    char arr[kNumberToStringBufferSize];
-    base::Vector<char> buffer(arr, arraysize(arr));
-    const char* string = DoubleToCString(value, buffer);
-    result = CharToString(this, string, mode);
-  }
-  if (mode != NumberCacheMode::kIgnore) {
-    NumberToStringCacheSet(number, hash, result);
-  }
-  return result;
-}
-
-inline Handle<String> Factory::SmiToString(Smi number, NumberCacheMode mode) {
-  int hash = NumberToStringCacheHash(number_string_cache(), number);
-  if (mode == NumberCacheMode::kBoth) {
-    Handle<Object> cached = NumberToStringCacheGet(number, hash);
-    if (!cached->IsUndefined(isolate())) return Handle<String>::cast(cached);
-  }
-
-  Handle<String> result;
-  if (number == Smi::zero()) {
-    result = zero_string();
-  } else {
-    char arr[kNumberToStringBufferSize];
-    base::Vector<char> buffer(arr, arraysize(arr));
-    const char* string = IntToCString(number.value(), buffer);
-    result = CharToString(this, string, mode);
-  }
-  if (mode != NumberCacheMode::kIgnore) {
-    NumberToStringCacheSet(handle(number, isolate()), hash, result);
-  }
-
-  // Compute the hash here (rather than letting the caller take care of it) so
-  // that the "cache hit" case above doesn't have to bother with it.
-  static_assert(Smi::kMaxValue <= std::numeric_limits<uint32_t>::max());
-  {
-    DisallowGarbageCollection no_gc;
-    String raw = *result;
-    if (raw.raw_hash_field() == String::kEmptyHashField &&
-        number.value() >= 0) {
-      uint32_t raw_hash_field = StringHasher::MakeArrayIndexHash(
-          static_cast<uint32_t>(number.value()), raw.length());
-      raw.set_raw_hash_field(raw_hash_field);
-    }
-  }
-  return result;
-}
-
 Handle<String> Factory::SizeToString(size_t value, bool check_cache) {
   Handle<String> result;
   NumberCacheMode cache_mode =

src/heap/factory.h

@@ -112,8 +112,6 @@ enum FunctionMode {
       kWithReadonlyPrototypeBit | kWithNameBit,
 };
 
-enum class NumberCacheMode { kIgnore, kSetOnly, kBoth };
-
 // Interface for handle based allocation.
 class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
  public:
@@ -228,9 +226,9 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   // two-byte.  One should choose between the three string factory functions
   // based on the encoding of the string buffer that the string is
   // initialized from.
-  //   - ...FromOneByte initializes the string from a buffer that is Latin1
-  //     encoded (it does not check that the buffer is Latin1 encoded) and
-  //     the result will be Latin1 encoded.
+  //   - ...FromOneByte (defined in FactoryBase) initializes the string from a
+  //     buffer that is Latin1 encoded (it does not check that the buffer is
+  //     Latin1 encoded) and the result will be Latin1 encoded.
   //   - ...FromUtf8 initializes the string from a buffer that is UTF-8
   //     encoded.  If the characters are all ASCII characters, the result
   //     will be Latin1 encoded, otherwise it will converted to two-byte.
@@ -239,10 +237,6 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   //     will be converted to Latin1, otherwise it will be left as two-byte.
   //
   // One-byte strings are pretenured when used as keys in the SourceCodeCache.
-  V8_WARN_UNUSED_RESULT MaybeHandle<String> NewStringFromOneByte(
-      const base::Vector<const uint8_t>& str,
-      AllocationType allocation = AllocationType::kYoung);
-
   template <size_t N>
   inline Handle<String> NewStringFromStaticChars(
       const char (&str)[N],
@@ -341,10 +335,6 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   ComputeSharingStrategyForString(Handle<String> string,
                                   MaybeHandle<Map>* shared_map);
 
-  // Creates a single character string where the character has given code.
-  // A cache is used for Latin1 codes.
-  Handle<String> LookupSingleCharacterStringFromCode(uint16_t code);
-
   // Create or lookup a single character string made up of a utf16 surrogate
   // pair.
   Handle<String> NewSurrogatePairString(uint16_t lead, uint16_t trail);
@@ -787,14 +777,6 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   DECLARE_ERROR(WasmExceptionError)
 #undef DECLARE_ERROR
 
-  Handle<String> NumberToString(Handle<Object> number,
-                                NumberCacheMode mode = NumberCacheMode::kBoth);
-  Handle<String> SmiToString(Smi number,
-                             NumberCacheMode mode = NumberCacheMode::kBoth);
-  Handle<String> HeapNumberToString(
-      Handle<HeapNumber> number, double value,
-      NumberCacheMode mode = NumberCacheMode::kBoth);
-
   Handle<String> SizeToString(size_t value, bool check_cache = true);
   inline Handle<String> Uint32ToString(uint32_t value,
                                        bool check_cache = true) {
@@ -802,7 +784,7 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   }
 
 #define ROOT_ACCESSOR(Type, name, CamelName) inline Handle<Type> name();
-  ROOT_LIST(ROOT_ACCESSOR)
+  MUTABLE_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
   // Allocates a new SharedFunctionInfo object.
@@ -1133,6 +1115,10 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   MaybeHandle<String> NewStringFromTwoByte(const base::uc16* string, int length,
                                            AllocationType allocation);
 
+  // Functions to get the hash of a number for the number_string_cache.
+  int NumberToStringCacheHash(Smi number);
+  int NumberToStringCacheHash(double number);
+
   // Attempt to find the number in a small cache.  If we finds it, return
   // the string representation of the number.  Otherwise return undefined.
   V8_INLINE Handle<Object> NumberToStringCacheGet(Object number, int hash);

src/heap/heap-inl.h

@@ -133,6 +133,11 @@ RootsTable& Heap::roots_table() { return isolate()->roots_table(); }
 MUTABLE_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
+FixedArray Heap::single_character_string_table() {
+  return FixedArray::cast(
+      Object(roots_table()[RootIndex::kSingleCharacterStringTable]));
+}
+
 #define ROOT_ACCESSOR(type, name, CamelName)                                   \
   void Heap::set_##name(type value) {                                          \
     /* The deserializer makes use of the fact that these common roots are */   \

src/heap/heap.h

@@ -939,6 +939,8 @@ class Heap {
   MUTABLE_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
+  V8_INLINE FixedArray single_character_string_table();
+
   V8_INLINE void SetRootMaterializedObjects(FixedArray objects);
   V8_INLINE void SetRootScriptList(Object value);
   V8_INLINE void SetRootNoScriptSharedFunctionInfos(Object value);

src/heap/local-factory-inl.h

@@ -12,13 +12,6 @@
 namespace v8 {
 namespace internal {
 
-#define ROOT_ACCESSOR(Type, name, CamelName)  \
-  Handle<Type> LocalFactory::name() {         \
-    return read_only_roots().name##_handle(); \
-  }
-READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
-#undef ROOT_ACCESSOR
-
 #define ACCESSOR_INFO_ACCESSOR(Type, name, CamelName)                          \
   Handle<Type> LocalFactory::name() {                                          \
     /* Do a bit of handle location magic to cast the Handle without having */  \

src/heap/local-factory.cc

@@ -8,6 +8,7 @@
 #include "src/execution/local-isolate.h"
 #include "src/handles/handles.h"
 #include "src/heap/concurrent-allocator-inl.h"
+#include "src/heap/local-factory-inl.h"
 #include "src/heap/local-heap-inl.h"
 #include "src/numbers/hash-seed-inl.h"
 #include "src/objects/fixed-array.h"
@@ -51,5 +52,16 @@ HeapObject LocalFactory::AllocateRaw(int size, AllocationType allocation,
       size, allocation, AllocationOrigin::kRuntime, alignment));
 }
 
+int LocalFactory::NumberToStringCacheHash(Smi) { return 0; }
+
+int LocalFactory::NumberToStringCacheHash(double) { return 0; }
+
+void LocalFactory::NumberToStringCacheSet(Handle<Object>, int, Handle<String>) {
+}
+
+Handle<Object> LocalFactory::NumberToStringCacheGet(Object, int) {
+  return undefined_value();
+}
+
 }  // namespace internal
 }  // namespace v8

src/heap/local-factory.h

@@ -33,7 +33,6 @@ class V8_EXPORT_PRIVATE LocalFactory : public FactoryBase<LocalFactory> {
   ReadOnlyRoots read_only_roots() const { return roots_; }
 
 #define ROOT_ACCESSOR(Type, name, CamelName) inline Handle<Type> name();
-  READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
   // AccessorInfos appear mutable, but they're actually not mutated once they
   // finish initializing. In particular, the root accessors are not mutated and
   // are safe to access (as long as the off-thread job doesn't try to mutate
@@ -48,6 +47,16 @@ class V8_EXPORT_PRIVATE LocalFactory : public FactoryBase<LocalFactory> {
     UNREACHABLE();
   }
 
+  // The LocalFactory does not have access to the number_string_cache (since
+  // it's a mutable root), but it still needs to define some cache-related
+  // method that are used by FactoryBase. Those method do basically nothing in
+  // the case of the LocalFactory.
+  int NumberToStringCacheHash(Smi number);
+  int NumberToStringCacheHash(double number);
+  void NumberToStringCacheSet(Handle<Object> number, int hash,
+                              Handle<String> js_string);
+  Handle<Object> NumberToStringCacheGet(Object number, int hash);
+
  private:
   friend class FactoryBase<LocalFactory>;
 

src/heap/setup-heap-internal.cc

@@ -691,7 +691,7 @@ void Heap::CreateInitialObjects() {
   // Allocate and initialize table for single character one byte strings.
   int table_size = String::kMaxOneByteCharCode + 1;
   set_single_character_string_table(
-      *factory->NewFixedArray(table_size, AllocationType::kOld));
+      *factory->NewFixedArray(table_size, AllocationType::kReadOnly));
   for (int i = 0; i < table_size; ++i) {
     uint8_t code = static_cast<uint8_t>(i);
     Handle<String> str =

src/roots/roots.h

@@ -23,6 +23,10 @@ template <typename T>
 class Handle;
 class Heap;
 class Isolate;
+class Factory;
+template <typename Impl>
+class FactoryBase;
+class LocalFactory;
 class Map;
 class PropertyCell;
 class ReadOnlyHeap;
@@ -195,6 +199,8 @@ class Symbol;
   V(HeapNumber, infinity_value, InfinityValue)                                 \
   V(HeapNumber, minus_zero_value, MinusZeroValue)                              \
   V(HeapNumber, minus_infinity_value, MinusInfinityValue)                      \
+  /* Table of strings of one-byte single characters */                         \
+  V(FixedArray, single_character_string_table, SingleCharacterStringTable)     \
   /* Marker for self-references during code-generation */                      \
   V(HeapObject, self_reference_marker, SelfReferenceMarker)                    \
   /* Marker for basic-block usage counters array during code-generation */     \
@@ -246,8 +252,6 @@ class Symbol;
   /* Caches */                                                                 \
   V(FixedArray, string_split_cache, StringSplitCache)                          \
   V(FixedArray, regexp_multiple_cache, RegExpMultipleCache)                    \
-  /* Table of strings of one-byte single characters */                         \
-  V(FixedArray, single_character_string_table, SingleCharacterStringTable)     \
   /* Indirection lists for isolate-independent builtins */                     \
   V(FixedArray, builtins_constants_table, BuiltinsConstantsTable)              \
   /* Internal SharedFunctionInfos */                                           \
@@ -568,6 +572,8 @@ class RootsTable {
   friend class Isolate;
   friend class Heap;
   friend class Factory;
+  friend class FactoryBase<Factory>;
+  friend class FactoryBase<LocalFactory>;
   friend class PointerCompressedReadOnlyArtifacts;
   friend class ReadOnlyHeap;
   friend class ReadOnlyRoots;