Changes to shrink the token stream representation from two words to one word.

vm/object_store.cc

Index: vm/object_store.cc
===================================================================
--- vm/object_store.cc	(revision 4579)
+++ vm/object_store.cc	(working copy)
@@ -54,6 +54,8 @@
     empty_context_(Context::null()),
     stack_overflow_(Instance::null()),
     out_of_memory_(Instance::null()),
+    literal_tokens_canonical_list_(Array::null()),
+    keyword_symbols_(Array::null()),
     preallocate_objects_called_(false) {
 }
 
@@ -104,6 +106,25 @@
 }
 
 
+RawObject* ObjectStore::GetKeywordSymbol(int index) {
+  Array& keywords = Array::Handle(keyword_symbols());
+  if (keywords.IsNull()) {

[hausner, 2012/02/25 00:41:57]

Could you move the creation of this table to the isolate initialization code?
That way you save a null check on this somewhat critical path.

It would also be nice if the keyword array were accessible to the scanner so it
can cache a handle to the array locally, saving a handle creation at each table
access.

[siva, 2012/02/28 19:57:31]

Done.

+    // Set up the keywords symbol array so that we can access it while scanning.
+    keywords = Array::New(Token::numKeywords, Heap::kOld);
+    ASSERT(!keywords.IsError() && !keywords.IsNull());
+    set_keyword_symbols(keywords);
+  }
+  return keywords.At(index);
+}
+
+
+void ObjectStore::SetKeywordSymbol(int index, const String& symbol) {
+  Array& keywords = Array::Handle(keyword_symbols());
+  ASSERT(!keywords.IsNull());
+  keywords.SetAt(index, symbol);
+}
+
+
 RawClass* ObjectStore::GetClass(int index) {
   switch (index) {
     case kObjectClass: return object_class_;