- Fix the x64 store-barrier.

runtime/vm/assembler_x64.cc

Index: runtime/vm/assembler_x64.cc
===================================================================
--- runtime/vm/assembler_x64.cc	(revision 9046)
+++ runtime/vm/assembler_x64.cc	(working copy)
@@ -1414,11 +1414,11 @@
 void Assembler::StoreIntoObjectFilter(Register object,

[cshapiro, 2012/06/22 23:22:40]

Document as destroying value?  Maybe in the header?

[Ivan Posva, 2012/06/22 23:42:21]

Done.

                                       Register value,
                                       Label* no_update) {
-  andl(value, Immediate(0x5));
+  andl(value, Immediate(0x9));

[cshapiro, 2012/06/22 23:22:40]

Can't these values be synthesized from constants?  That would help insulate us
against errors.  0x9 is just a mask composed from the object/smi bit and the
generation bit.

[Ivan Posva, 2012/06/22 23:42:21]

Using the constants would actually be a very nice way of documenting the bit
twiddling. Thanks! Next CL.

   shrl(value, Immediate(1));
   adcl(value, object);
-  andl(value, Immediate(0x7));
-  cmpl(value, Immediate(0x4));
+  andl(value, Immediate(0xf));

[cshapiro, 2012/06/22 23:22:40]

ditto

+  cmpl(value, Immediate(0x6));

[cshapiro, 2012/06/22 23:22:40]

ditto

   j(NOT_ZERO, no_update, Assembler::kNearJump);
 }