Simplify and fix code aging.

src/x64/codegen-x64.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 663 matching lines @@
     patcher.masm()->push(rbp);
     patcher.masm()->movq(rbp, rsp);
     patcher.masm()->push(rsi);
     patcher.masm()->push(rdi);
     initialized = true;
   }
   return sequence;
 }
 
 
-byte* Code::FindPlatformCodeAgeSequence() {
-  byte* start = instruction_start();
-  uint32_t young_length;
-  byte* young_sequence = GetNoCodeAgeSequence(&young_length);
-  if (!memcmp(start, young_sequence, young_length) ||
-      *start == kCallOpcode) {
-    return start;
-  } else {
-    byte* start_after_strict = NULL;
-    if (kind() == FUNCTION) {
-      start_after_strict = start + kSizeOfFullCodegenStrictModePrologue;
-    } else {
-      ASSERT(kind() == OPTIMIZED_FUNCTION);
-      start_after_strict = start + kSizeOfOptimizedStrictModePrologue;
-    }
-    ASSERT(!memcmp(start_after_strict, young_sequence, young_length) ||
-           *start_after_strict == kCallOpcode);
-    return start_after_strict;
-  }
-}
-
-
 bool Code::IsYoungSequence(byte* sequence) {
   uint32_t young_length;
   byte* young_sequence = GetNoCodeAgeSequence(&young_length);
   bool result = (!memcmp(sequence, young_sequence, young_length));
   ASSERT(result || *sequence == kCallOpcode);
   return result;
 }
 
 
 void Code::GetCodeAgeAndParity(byte* sequence, Age* age,
@@ skipping 24 matching lines @@
     CodePatcher patcher(sequence, young_length);
     patcher.masm()->call(stub->instruction_start());
     patcher.masm()->nop();
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64