Proper support for deopt_every_n_times option on the x64 and ARM architectures.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 631 matching lines @@
   ASSERT(environment->HasBeenRegistered());
   int id = environment->deoptimization_index();
   ASSERT(info()->IsOptimizing() || info()->IsStub());
   Address entry =
       Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
   if (entry == NULL) {
     Abort(kBailoutWasNotPrepared);
     return;
   }
 
-  ASSERT(FLAG_deopt_every_n_times == 0);  // Not yet implemented on x64.
+  if (FLAG_deopt_every_n_times != 0 && !info()->IsStub()) {
+    ExternalReference count = ExternalReference::stress_deopt_count(isolate());
+    Label no_deopt;
+    __ pushfq();
+    __ push(rax);
+    Operand count_operand = __ ExternalOperand(count, kScratchRegister);

[Weiliang, 2013/11/07 09:20:11]

drive-by comments 
use masm()-> instead of __ here for ExternalOperand

+    __ movl(rax, count_operand);
+    __ subl(rax, Immediate(1));
+    __ j(not_zero, &no_deopt, Label::kNear);
+    if (FLAG_trap_on_deopt) __ int3();
+    __ movl(rax, Immediate(FLAG_deopt_every_n_times));
+    __ movl(count_operand, rax);
+    __ pop(rax);
+    __ popfq();
+    ASSERT(frame_is_built_);
+    __ call(entry, RelocInfo::RUNTIME_ENTRY);
+    __ bind(&no_deopt);
+    __ movl(count_operand, rax);
+    __ pop(rax);
+    __ popfq();
+  }
 
   if (info()->ShouldTrapOnDeopt()) {
     Label done;
     if (cc != no_condition) {
       __ j(NegateCondition(cc), &done, Label::kNear);
     }
     __ int3();
     __ bind(&done);
   }
 
@@ skipping 4836 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64