A64: Add suport for the --trap_on_deopt option.

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 867 matching lines @@
   int id = environment->deoptimization_index();
   Address entry =
       Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
 
   if (entry == NULL) {
     Abort("bailout was not prepared");
     return;
   }
 
   TODO_UNIMPLEMENTED("Add support for deopt_every_n_times flag.");
-  TODO_UNIMPLEMENTED("Add support for trap_on_deopt flag.");
+  if (FLAG_trap_on_deopt && info()->IsOptimizing()) {
+    __ Debug("trap_on_deopt", __LINE__, BREAK);
+  }
+
 
   // TODO(all): Currently this code directly jump to the second level deopt
   // table entry. This code need to be updated if we decide to use the
   // 2 levels of table.
   ASSERT(info()->IsStub() || frame_is_built_);
   bool needs_lazy_deopt = info()->IsStub();
   if (frame_is_built_) {
     if (needs_lazy_deopt) {
       __ Call(entry, RelocInfo::RUNTIME_ENTRY);
     } else {
@@ skipping 4674 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