Implements a new API to set a function entry hook for profiling.

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 110 matching lines @@
   int length = builder.position();
   Vector<char> copy = Vector<char>::New(length + 1);
   memcpy(copy.start(), builder.Finalize(), copy.length());
   masm()->RecordComment(copy.start());
 }
 
 
 bool LCodeGen::GeneratePrologue() {
   ASSERT(is_generating());
 
+  ProfileEntryHookStub::MaybeCallEntryHook(masm_);
+
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       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
@@ skipping 4904 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64