A64: Add support for --deopt-every-n-times for n != 2

src/a64/lithium-codegen-a64.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 940 matching lines @@
   Deoptimizer::BailoutType bailout_type = info()->IsStub() ? Deoptimizer::LAZY
                                                            : Deoptimizer::EAGER;
   Address entry =
       Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
 
   if (entry == NULL) {
     Abort(kBailoutWasNotPrepared);
     return false;
   }
 
-  ASSERT(FLAG_deopt_every_n_times < 2);  // Other values not supported on A64.
-  TODO_UNIMPLEMENTED("Support for FLAG_deopt_every_n_times >= 2.");
-  if (FLAG_deopt_every_n_times == 1 &&
-      !info()->IsStub() &&
-      info()->opt_count() == id) {
-    ASSERT(frame_is_built_);
+  if (FLAG_deopt_every_n_times != 0 && !info()->IsStub()) {
+    Label not_zero;
+    ExternalReference count = ExternalReference::stress_deopt_count(isolate());
+
+    __ Push(x0, x1);
+    __ Mov(x0, Operand(count));
+    __ Ldr(w1, MemOperand(x0));
+    __ Subs(x1, x1, 1);
+    __ B(ge, &not_zero);
+    __ Mov(w1, FLAG_deopt_every_n_times);
+    __ Str(w1, MemOperand(x0));
+    __ Pop(x0, x1);
     __ Call(entry, RelocInfo::RUNTIME_ENTRY);
     return false;

[jochen (gone - plz use gerrit), 2014/02/10 14:32:07]

It doesn't really matter what we return here, because the call will never
return...

+
+    __ Bind(not_zero);
+    __ Str(w1, MemOperand(x0));
+    __ Pop(x0, x1);
+    return true;
   }
 
   return true;
 }
 
 
 void LCodeGen::Deoptimize(LEnvironment* environment,
                           Deoptimizer::BailoutType bailout_type) {
   if (!DeoptimizeHeader(environment)) return;
 
@@ skipping 4673 matching lines @@
   __ Bind(&out_of_object);
   __ Ldr(result, FieldMemOperand(object, JSObject::kPropertiesOffset));
   // Index is equal to negated out of object property index plus 1.
   __ Sub(result, result, Operand::UntagSmiAndScale(index, kPointerSizeLog2));
   __ Ldr(result, FieldMemOperand(result,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ Bind(&done);
 }
 
 } }  // namespace v8::internal