Fix/implement new write barrier for x64.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
===================================================================
--- src/x64/ic-x64.cc	(revision 6183)
+++ src/x64/ic-x64.cc	(working copy)
@@ -269,10 +269,8 @@
   __ movq(Operand(scratch1, 0), value);
 
   // Update write barrier. Make sure not to clobber the value.
-#ifdef ENABLE_CARDMARKING_WRITE_BARRIER
   __ movq(scratch0, value);
-  __ RecordWrite(elements, scratch1, scratch0);
-#endif
+  __ RecordWrite(elements, scratch1, scratch0, kDontSaveFPRegs);
 }
 
 
@@ -1019,10 +1017,8 @@
   __ bind(&non_smi_value);
   // Slow case that needs to retain rcx for use by RecordWrite.
   // Update write barrier for the elements array address.
-#ifdef ENABLE_CARDMARKING_WRITE_BARRIER
   __ movq(rdx, rax);
-  __ RecordWriteNonSmi(rbx, 0, rdx, rcx);
-#endif
+  __ RecordWriteNonSmi(rbx, 0, rdx, rcx, kDontSaveFPRegs);
   __ ret(0);
 }
 
@@ -1638,9 +1634,7 @@
   Address encoded_offsets_address = test_instruction_address + 1;
   int encoded_offsets = *reinterpret_cast<int*>(encoded_offsets_address);
   int delta_to_map_check = -(encoded_offsets & 0xFFFF);
-#ifdef ENABLE_CARDMARKING_WRITE_BARRIER
   int delta_to_record_write = encoded_offsets >> 16;
-#endif
 
   // Patch the map to check. The map address is the last 8 bytes of
   // the 10-byte immediate move instruction.
@@ -1659,7 +1653,6 @@
          (offset == 0 && map == Heap::null_value()));
   *reinterpret_cast<int*>(offset_address) = offset - kHeapObjectTag;
 
-#ifdef ENABLE_CARDMARKING_WRITE_BARRIER
   // Patch the offset in the write-barrier code. The offset is the
   // last 4 bytes of a 7 byte lea instruction.
   offset_address = map_check_address + delta_to_record_write + 3;
@@ -1669,7 +1662,6 @@
          *reinterpret_cast<int*>(offset_address) == -1 ||
          (offset == 0 && map == Heap::null_value()));
   *reinterpret_cast<int*>(offset_address) = offset - kHeapObjectTag;
-#endif
 
   return true;
 }