Inline String.fromCharCode in hydrogen.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index dffa959c3cb3473f972770bd70b9bff973157e6e..d71383d6e571c818ef0e59382ffaa3610b10ae53 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -2417,9 +2417,7 @@ MUST_USE_RESULT static MaybeObject* CharFromCode(Isolate* isolate,
                                                  Object* char_code) {
   uint32_t code;
   if (char_code->ToArrayIndex(&code)) {

[Toon Verwaest, 2013/04/16 22:19:30]

This currently works by accident I presume; given that ToArrayIndex has a buggy
implementation. 0xFFFFFFFF isn't a valid array index, even though currently we
interpret it as such. This probably wants to convert it to a valid UInt32;
probably best to fix up the API usage to avoid future breakage. And maybe add a
test for 0xFFFFFFFF if there isn't one yet.

-    if (code <= 0xffff) {
-      return isolate->heap()->LookupSingleCharacterStringFromCode(code);
-    }
+    return isolate->heap()->LookupSingleCharacterStringFromCode(code & 0xffff);
   }
   return isolate->heap()->empty_string();
 }