Make one-ascii-character-string a symbol in its cache.

src/heap.cc

Index: src/heap.cc
===================================================================
--- src/heap.cc	(revision 528)
+++ src/heap.cc	(working copy)
@@ -1488,16 +1488,20 @@
 }
 
 
-Object* Heap:: LookupSingleCharacterStringFromCode(uint16_t code) {
+Object* Heap::LookupSingleCharacterStringFromCode(uint16_t code) {
   if (code <= String::kMaxAsciiCharCode) {
     Object* value = Heap::single_character_string_cache()->get(code);
     if (value != Heap::undefined_value()) return value;
-    Object* result = Heap::AllocateRawAsciiString(1);
+
+    char buffer[1];
+    buffer[0] = static_cast<char>(code);
+    Object* result = LookupSymbol(Vector<const char>(buffer, 1));
+
     if (result->IsFailure()) return result;
-    String::cast(result)->Set(0, code);
     Heap::single_character_string_cache()->set(code, result);
     return result;
   }
+
   Object* result = Heap::AllocateRawTwoByteString(1);

[iposva, 2008/10/21 04:33:46]

Is there a reason we do not symbolize one character two byte strings? Just no
frequent enough?

[Feng Qian, 2008/10/21 16:27:11]

I viewed single_character_string_cache is a cache on top of symbol table, and
two-byte chars are not cached, so I didn't feel strongly to symbolize it.

On 2008/10/21 04:33:46, iposva wrote:

   if (result->IsFailure()) return result;
   String::cast(result)->Set(0, code);