sysdeps/generic/dl-symbol-redir-ifunc.h

   1 /* Symbol rediretion for loader/static initialization code.
   2    Copyright (C) 2022-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _DL_IFUNC_GENERIC_H
  20 #define _DL_IFUNC_GENERIC_H
  21
  22 /* The compiler might optimize loops or other constructs to library calls even
  23    in freestanding mode.  Although it is safe in most scenarios, on program
  24    loading and static startup, iFUNC resolution might require other dynamic
  25    relocation that are not yet done.
  26
  27    Instead of adding per-file compiler flags to avoid the libcall generation,
  28    this header defines generic symbols that will be routed instead of the
  29    default symbols name.
  30
  31    Each port can then make the required redirection to the expected generic
  32    implementation if the symbol is provided as iFUNC, with a global definition
  33    such as:
  34
  35      asm ("memset = __memset_generic");
  36  */
  37
  38 #endif