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5355f9ca7b
Besides the option being gcc specific, this approach is still fragile and not future proof since we do not know if this will be the only optimization option gcc will add that transforms loops to memset (or any libcall). This patch adds a new header, dl-symbol-redir-ifunc.h, that can b used to redirect the compiler generated libcalls to port the generic memset implementation if required. Checked on x86_64-linux-gnu and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
39 lines
1.5 KiB
C
39 lines
1.5 KiB
C
/* Symbol rediretion for loader/static initialization code.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _DL_IFUNC_GENERIC_H
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#define _DL_IFUNC_GENERIC_H
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/* The compiler might optimize loops or other constructs to library calls even
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in freestanding mode. Although it is safe in most scenarios, on program
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loading and static startup, iFUNC resolution might require other dynamic
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relocation that are not yet done.
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Instead of adding per-file compiler flags to avoid the libcall generation,
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this header defines generic symbols that will be routed instead of the
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default symbols name.
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Each port can then make the required redirection to the expected generic
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implementation if the symbol is provided as iFUNC, with a global definition
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such as:
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asm ("memset = __memset_generic");
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*/
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#endif
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