//===- x86_64 implementation of the get_start_args_addr function -*- C++ -*===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

%%begin()

namespace __llvm_libc {

__attribute__((always_inline)) inline uintptr_t get_start_args_addr() {
  // NOTE: For __builtin_frame_address to work reliably across compilers,
  // architectures and various optimization levels, the TU including this file
  // should be compiled with -fno-omit-frame-pointer.
  return reinterpret_cast<uintptr_t>(__builtin_frame_address(0)) +
         // The x86_64 call instruction pushes resume address on to the stack.
         // Next, The x86_64 SysV ABI also pushes the frame pointer on the
         // stack. Hence, we look past these items to get to the start args.
         sizeof(uintptr_t) * 2;
}

} // namespace __llvm_libc