Port inline swapping of elements for the sort function in array.js...

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
===================================================================
--- src/x64/macro-assembler-x64.cc	(revision 4574)
+++ src/x64/macro-assembler-x64.cc	(working copy)
@@ -75,6 +75,14 @@
 void MacroAssembler::RecordWriteHelper(Register object,
                                        Register addr,
                                        Register scratch) {
+  if (FLAG_debug_code) {
+    // Check that the object is not in new space.
+    Label not_in_new_space;
+    InNewSpace(object, scratch, not_equal, &not_in_new_space);
+    Abort("new-space object passed to RecordWriteHelper");
+    bind(&not_in_new_space);
+  }
+
   Label fast;
 
   // Compute the page start address from the heap object pointer, and reuse
@@ -157,7 +165,7 @@
 
   // First, check if a remembered set write is even needed. The tests below
   // catch stores of Smis and stores into young gen (which does not have space
-  // for the remembered set bits.
+  // for the remembered set bits).
   Label done;
   JumpIfSmi(value, &done);