glibc/sysdeps/wordsize-32/divdi3-symbol-hacks.h

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Build divdi3 only for architecture that required it As noted in [1], divdi3 object is only exported in a handful ABIs (i386, m68k, powerpc32, s390-32, and ia64), however it is built for all current architectures regardless. This patch refact the make rules for this object to so only the aforementioned architectures that actually require it builds it. Also, to avoid internal PLT calls to the exported symbol from the module, glibc uses an internal header (symbol-hacks.h) which is unrequired (and in fact breaks the build for architectures that intend to get symbol definitions from libgcc.a). The patch also changes it to create its own header (divdi3-symbol-hacks.h) and adjust the architectures that require it accordingly. I checked the build/check (with run-built-tests=no) on the following architectures (which I think must cover all supported ABI/builds) using GCC 6.3: aarch64-linux-gnu alpha-linux-gnu arm-linux-gnueabihf hppa-linux-gnu ia64-linux-gnu m68k-linux-gnu microblaze-linux-gnu mips64-n32-linux-gnu mips-linux-gnu mips64-linux-gnu nios2-linux-gnu powerpc-linux-gnu powerpc-linux-gnu-power4 powerpc64-linux-gnu powerpc64le-linux-gnu s390x-linux-gnu s390-linux-gnu sh4-linux-gnu sh4-linux-gnu-soft sparc64-linux-gnu sparcv9-linux-gnu tilegx-linux-gnu tilegx-linux-gnu-32 tilepro-linux-gnu x86_64-linux-gnu x86_64-linux-gnu-x32 i686-linux-gnu I only saw one regression on sparcv9-linux-gnu (extra PLT call to .udiv) which I address in next patch in the set. It also correctly build SH with GCC 7.0.1 (without any regression from c89721e25d). [1] https://sourceware.org/ml/libc-alpha/2017-03/msg00243.html * sysdeps/i386/symbol-hacks.h: New file. * sysdeps/m68k/symbol-hacks.h: New file. * sysdeps/powerpc/powerpc32/symbol-hacks.h: New file. * sysdeps/s390/s390-32/symbol-hacks.h: New file. * sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = csu] (sysdep_routines): New rule: divdi3 object. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/m68k/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/wordsize-32/Makefile: Remove file. * sysdeps/wordsize-32/symbol-hacks.h: Definitions move to ... * sysdeps/wordsize-32/divdi3-symbol-hacks.h: ... here.
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/* Hacks needed for divdi3 symbol manipulation.
Copyright (C) 2004-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
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<https://www.gnu.org/licenses/>. */
/* A very dirty trick: gcc emits references to __divdi3, __udivdi3,
__moddi3, and __umoddi3. These functions are exported and
therefore we get PLTs. Unnecessarily so. Changing gcc is a big
task which might not be worth it so we play tricks with the
Build divdi3 only for architecture that required it As noted in [1], divdi3 object is only exported in a handful ABIs (i386, m68k, powerpc32, s390-32, and ia64), however it is built for all current architectures regardless. This patch refact the make rules for this object to so only the aforementioned architectures that actually require it builds it. Also, to avoid internal PLT calls to the exported symbol from the module, glibc uses an internal header (symbol-hacks.h) which is unrequired (and in fact breaks the build for architectures that intend to get symbol definitions from libgcc.a). The patch also changes it to create its own header (divdi3-symbol-hacks.h) and adjust the architectures that require it accordingly. I checked the build/check (with run-built-tests=no) on the following architectures (which I think must cover all supported ABI/builds) using GCC 6.3: aarch64-linux-gnu alpha-linux-gnu arm-linux-gnueabihf hppa-linux-gnu ia64-linux-gnu m68k-linux-gnu microblaze-linux-gnu mips64-n32-linux-gnu mips-linux-gnu mips64-linux-gnu nios2-linux-gnu powerpc-linux-gnu powerpc-linux-gnu-power4 powerpc64-linux-gnu powerpc64le-linux-gnu s390x-linux-gnu s390-linux-gnu sh4-linux-gnu sh4-linux-gnu-soft sparc64-linux-gnu sparcv9-linux-gnu tilegx-linux-gnu tilegx-linux-gnu-32 tilepro-linux-gnu x86_64-linux-gnu x86_64-linux-gnu-x32 i686-linux-gnu I only saw one regression on sparcv9-linux-gnu (extra PLT call to .udiv) which I address in next patch in the set. It also correctly build SH with GCC 7.0.1 (without any regression from c89721e25d). [1] https://sourceware.org/ml/libc-alpha/2017-03/msg00243.html * sysdeps/i386/symbol-hacks.h: New file. * sysdeps/m68k/symbol-hacks.h: New file. * sysdeps/powerpc/powerpc32/symbol-hacks.h: New file. * sysdeps/s390/s390-32/symbol-hacks.h: New file. * sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = csu] (sysdep_routines): New rule: divdi3 object. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/m68k/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/Makefile [$(subdir) = csu] (sysdep_routines): Likewise. [$(subdir) = csu] (sysdep-only-routines): Likewise. [$(subdir) = csu] (CFLAGS-divdi3.c): Likewise. * sysdeps/wordsize-32/Makefile: Remove file. * sysdeps/wordsize-32/symbol-hacks.h: Definitions move to ... * sysdeps/wordsize-32/divdi3-symbol-hacks.h: ... here.
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assembler.
Note: in_divdi3_c is only used to avoid symbol alias on divdi3
build itself. */
#if !defined __ASSEMBLER__ && !defined in_divdi3_c && IS_IN (libc) \
&& defined SHARED && !defined LIBC_NONSHARED
asm ("__divdi3 = __divdi3_internal");
asm ("__udivdi3 = __udivdi3_internal");
asm ("__moddi3 = __moddi3_internal");
asm ("__umoddi3 = __umoddi3_internal");
#endif