The check for internalized strings relied on the fact that we had less

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 55759856a54a6581c859bdfc0294d723dbf70343..eee5e1bca14a774acb759e0e2b72b8e88bb7311e 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -2308,6 +2308,27 @@ void MacroAssembler::JumpIfBothInstanceTypesAreNotSequentialAscii(
 }
 
 
+void MacroAssembler::JumpIfNotUniqueName(Operand operand,
+                                         Label* not_unique_name,
+                                         Label::Distance distance) {
+  STATIC_ASSERT(((SYMBOL_TYPE - 1) & kIsInternalizedMask) == kInternalizedTag);
+  cmpb(operand, Immediate(kInternalizedTag));
+  j(less, not_unique_name, distance);
+  cmpb(operand, Immediate(SYMBOL_TYPE));
+  j(greater, not_unique_name, distance);
+}
+
+
+void MacroAssembler::JumpIfNotUniqueName(Register reg,

[Yang, 2013/06/27 07:48:36]

This is like, a character-by-character copy. Could you use some template magic
here?

[mvstanton, 2013/06/27 13:35:20]

Done.

+                                         Label* not_unique_name,
+                                         Label::Distance distance) {
+  STATIC_ASSERT(((SYMBOL_TYPE - 1) & kIsInternalizedMask) == kInternalizedTag);
+  cmpb(reg, Immediate(kInternalizedTag));
+  j(less, not_unique_name, distance);
+  cmpb(reg, Immediate(SYMBOL_TYPE));
+  j(greater, not_unique_name, distance);
+}
+
 
 void MacroAssembler::Move(Register dst, Register src) {
   if (!dst.is(src)) {