Simplify and fix code aging.

src/x64/lithium-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 115 matching lines @@
       info_->function()->name()->IsEqualTo(CStrVector(FLAG_stop_at))) {
     __ int3();
   }
 #endif
 
   // Strict mode functions need to replace the receiver with undefined
   // when called as functions (without an explicit receiver
   // object). rcx is zero for method calls and non-zero for function
   // calls.
   if (!info_->is_classic_mode() || info_->is_native()) {
-    Label begin;
-    __ bind(&begin);
     Label ok;
     __ testq(rcx, rcx);
     __ j(zero, &ok, Label::kNear);
     // +1 for return address.
     int receiver_offset = (scope()->num_parameters() + 1) * kPointerSize;
     __ LoadRoot(kScratchRegister, Heap::kUndefinedValueRootIndex);
     __ movq(Operand(rsp, receiver_offset), kScratchRegister);
     __ bind(&ok);
-    ASSERT(!FLAG_age_code ||
-           (kSizeOfOptimizedStrictModePrologue == ok.pos() - begin.pos()));
   }
 
+  info()->set_prologue_offset(masm_->pc_offset());
   __ push(rbp);  // Caller's frame pointer.
   __ movq(rbp, rsp);
   __ push(rsi);  // Callee's context.
   __ push(rdi);  // Callee's JS function.
 
   // Reserve space for the stack slots needed by the code.
   int slots = GetStackSlotCount();
   if (slots > 0) {
     if (FLAG_debug_code) {
       __ Set(rax, slots);
@@ skipping 5221 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64