A64: Synchronize with r16356.

src/a64/simulator-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 3128 matching lines @@
                  reinterpret_cast<void*>(redirection->external_function()));
 
         // SP must be 16 bytes aligned at the call interface.
         bool stack_alignment_exception = ((sp() & 0xf) != 0);
         if (stack_alignment_exception) {
           TraceSim("  with unaligned stack 0x%016" PRIx64 ".\n", sp());
           ALIGNMENT_EXCEPTION();
         }
 
         switch (redirection->type()) {
+          // TODO(jbramley): The old-style callbacks (returning a Handle) have
+          // been removed. We should remove their handlers from here, too.
+
           default:
             TraceSim("Type: Unknown.\n");
             UNREACHABLE();
             break;
 
           case ExternalReference::BUILTIN_CALL: {
             // MaybeObject* f(v8::internal::Arguments).
             TraceSim("Type: BUILTIN_CALL\n");
             SimulatorRuntimeCall target =
                 reinterpret_cast<SimulatorRuntimeCall>(external);
@@ skipping 259 matching lines @@
     default:
       UNIMPLEMENTED();
   }
 }
 
 #endif  // USE_SIMULATOR
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64