Simplify and fix code aging.

src/objects.cc

 // Copyright 2012 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 8857 matching lines @@
   if (sequence == NULL) return false;
   Age age;
   MarkingParity parity;
   GetCodeAgeAndParity(sequence, &age, &parity);
   return age >= kSexagenarianCodeAge;
 }
 
 
 byte* Code::FindCodeAgeSequence() {
   return FLAG_age_code &&
-      strlen(FLAG_stop_at) == 0 &&
-      !ProfileEntryHookStub::HasEntryHook() &&
+      prologue_offset() != kPrologueOffsetNotSet &&
       (kind() == OPTIMIZED_FUNCTION ||
        (kind() == FUNCTION && !has_debug_break_slots()))
-      ? FindPlatformCodeAgeSequence()
+      ? instruction_start() + prologue_offset()
       : NULL;
 }
 
 
 void Code::GetCodeAgeAndParity(Code* code, Age* age,
                                MarkingParity* parity) {
   Isolate* isolate = Isolate::Current();
   Builtins* builtins = isolate->builtins();
   Code* stub = NULL;
 #define HANDLE_CODE_AGE(AGE)                                            \
@@ skipping 4989 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal