Replace the use CharacterStreams in Heap::AllocateSymbolInternal and String::ComputeHash

src/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 80 matching lines @@
   if (non_ascii_start >= length) {
     // If the string is ASCII, we do not need to convert the characters
     // since UTF8 is backwards compatible with ASCII.
     return AllocateStringFromOneByte(str, pretenure);
   }
   // Non-ASCII and we need to decode.
   return AllocateStringFromUtf8Slow(str, non_ascii_start, pretenure);
 }
 
 
+template<>
+bool inline Heap::IsOneByte(Vector<const char> str, int chars) {
+  // TODO(dcarney): incorporate Latin-1 check when Latin-1 is supported?
+  // ASCII only check.
+  return chars == str.length();
+}
+
+
+template<>
+bool inline Heap::IsOneByte(String* str, int chars) {
+  return str->IsOneByteRepresentation();
+}
+
+
 MaybeObject* Heap::AllocateSymbol(Vector<const char> str,
                                   int chars,
                                   uint32_t hash_field) {
-  unibrow::Utf8InputBuffer<> buffer(str.start(),
-                                    static_cast<unsigned>(str.length()));
-  return AllocateInternalSymbol(&buffer, chars, hash_field);
+  if (IsOneByte(str, chars)) return AllocateAsciiSymbol(str, hash_field);
+  return AllocateInternalSymbol<false>(str, chars, hash_field);
 }
 
 
+template<typename T>
+MaybeObject* Heap::AllocateInternalSymbol(T t, int chars, uint32_t hash_field) {
+  if (IsOneByte(t, chars)) {
+    return AllocateInternalSymbol<true>(t, chars, hash_field);
+  }
+  return AllocateInternalSymbol<false>(t, chars, hash_field);
+}
+
+
 MaybeObject* Heap::AllocateAsciiSymbol(Vector<const char> str,
                                        uint32_t hash_field) {
   if (str.length() > SeqOneByteString::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   // Compute map and object size.
   Map* map = ascii_symbol_map();
   int size = SeqOneByteString::SizeFor(str.length());
 
   // Allocate string.
@@ skipping 697 matching lines @@
 AssertNoAllocation::~AssertNoAllocation() { }
 DisableAssertNoAllocation::DisableAssertNoAllocation() { }
 DisableAssertNoAllocation::~DisableAssertNoAllocation() { }
 
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_