glibc/sysdeps/unix/sysv/linux/i386/configure.ac

GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
# Local configure fragment for sysdeps/unix/sysv/linux/i386.

arch_minimum_kernel=2.6.32

# Check if CFLAGS allows compiler to use ebp register in inline assembly.
AC_CACHE_CHECK([if compiler flags allows ebp in inline assembly],
                libc_cv_can_use_register_asm_ebp, [
AC_COMPILE_IFELSE(
  [AC_LANG_PROGRAM([
    void foo (int i)
    {
      register int reg asm ("ebp") = i;
      asm ("# %0" : : "r" (reg));
    }])],
  [libc_cv_can_use_register_asm_ebp=yes],
  [libc_cv_can_use_register_asm_ebp=no])
])
if test $libc_cv_can_use_register_asm_ebp = yes; then
  AC_DEFINE(CAN_USE_REGISTER_ASM_EBP)
fi

libc_cv_gcc_unwind_find_fde=yes
ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed
Move architecture cases out of sysdeps/unix/sysv/linux/configure.ac. Continuing the process of making non-ex-ports architectures follow the preferred sysdeps practices followed by ex-ports architectures - that is, putting things in architecture-specific sysdeps files rather than having architecture-specific cases in architecture-independent files - this patch moves architecture cases out of sysdeps/unix/sysv/linux/configure.ac into (new or existing) configure fragments for each architecture. (In the case of the arch_minimum_kernel setting for x32, sysdeps/unix/sysv/linux/x86_64/x32/configure already has such a setting so the setting in sysdeps/unix/sysv/linux/configure.ac was a duplicate that could just be removed - though I haven't tested for x32.) Tested for x86_64 and x86 that the patch causes no changes to the installed shared libraries or ldd (or any part of the installation except for the parts that always change because the files contain timestamps - nscd and static libraries). * sysdeps/unix/sysv/linux/configure.ac: Remove cases for individual architectures. * sysdeps/unix/sysv/linux/configure: Regenerated. * sysdeps/unix/sysv/linux/i386/configure.ac: New file. * sysdeps/unix/sysv/linux/i386/configure: New generated file. * sysdeps/unix/sysv/linux/powerpc/configure.ac (ldd_rewrite_script): Define variable. * sysdeps/unix/sysv/linux/powerpc/configure: Regenerated. * sysdeps/unix/sysv/linux/powerpc/powerpc32/configure.ac: New file. * sysdeps/unix/sysv/linux/powerpc/powerpc32/configure: New generated file. * sysdeps/unix/sysv/linux/s390/configure.ac: New file. * sysdeps/unix/sysv/linux/s390/configure: New generated file. * sysdeps/unix/sysv/linux/sh/configure.ac: New file. * sysdeps/unix/sysv/linux/sh/configure: New generated file. * sysdeps/unix/sysv/linux/sparc/configure.ac: New file. * sysdeps/unix/sysv/linux/sparc/configure: New generated file. * sysdeps/unix/sysv/linux/x86_64/configure.ac: New file. * sysdeps/unix/sysv/linux/x86_64/configure: New generated file. 2014-06-24 20:53:03 +00:00			`GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.`
			`# Local configure fragment for sysdeps/unix/sysv/linux/i386.`

Require Linux 3.2 except on x86 / x86_64, 3.2 headers everywhere. In <https://sourceware.org/ml/libc-alpha/2016-01/msg00885.html> I proposed a minimum Linux kernel version of 3.2 for glibc 2.24, since Linux 2.6.32 has reached EOL. In the discussion in February, some concerns were expressed about compatibility with OpenVZ containers. It's not clear that these are real issues, given OpenVZ backporting kernel features and faking the kernel version for guest software, as discussed in <https://sourceware.org/ml/libc-alpha/2016-02/msg00278.html>. It's also not clear that supporting running GNU/Linux distributions from late 2016 (at the earliest) on a kernel series from 2009 is a sensible expectation. However, as an interim step, this patch increases the requirement everywhere except x86 / x86_64 (since the controversy was only about those architectures); the special caveats and settings can easily be removed later when we're ready to increase the requirements on x86 / x86_64 (and if someone would like to raise the issue on LWN as suggested in the previous discussion, that would be welcome). 3.2 kernel headers are required everywhere by this patch. (x32 already requires 3.4 or later, so is unaffected by this patch.) As usual for such a change, this patch only changes the configure scripts and associated documentation. The intent is to follow up with removal of dead __LINUX_KERNEL_VERSION conditionals. Each __ASSUME_* or other macro that becomes dead can then be removed independently. Tested for x86_64 and x86. * sysdeps/unix/sysv/linux/configure.ac (LIBC_LINUX_VERSION): Define to 3.2.0. (arch_minimum_kernel): Likewise. * sysdeps/unix/sysv/linux/configure: Regenerated. * sysdeps/unix/sysv/linux/i386/configure.ac (arch_minimum_kernel): Define to 2.6.32. * sysdeps/unix/sysv/linux/i386/configure: Regenerated. * sysdeps/unix/sysv/linux/x86_64/64/configure.ac (arch_minimum_kernel): Define to 2.6.32. * sysdeps/unix/sysv/linux/x86_64/64/configure: Regenerated. * README: Document Linux 3.2 requirement. * manual/install.texi (Linux): Document Linux 3.2 headers requirement. * INSTALL: Regenerated. 2016-02-24 17:15:12 +00:00			`arch_minimum_kernel=2.6.32`

Rework -fno-omit-frame-pointer support on i386 Commit 6b1df8b27f fixed the -OS build issue on i386 (BZ#20729) by expliciting disabling frame pointer (-fomit-frame-pointer) on the faulty objects. Although it does fix the issue, it is a subpar workaround that adds complexity in build process (a rule for each object to add the required compiler option and pontentially more rules for objects that call {INLINE,INTERNAL}_SYSCALL) and does not allow the implementations to get all the possible debug/calltrack information possible (used mainly in debuggers and performance measurement tools). This patch fixes it by adding an explicit configure check to see if -fno-omit-frame-pointer is set and to act accordingly (set or not OPTIMIZE_FOR_GCC_5). The make rules is simplified and only one is required: to add libc-do-syscall on loader due mmap (which will be empty anyway for default build with -fomit-frame-pointer). Checked on i386-linux-gnu with GCC 6.2.1 with CFLAGS sets as '-Os', '-O2 -fno-omit-frame-pointer', and '-O2 -fomit-frame-pointer'. For '-Os' the testsuite issues described by BZ#19463 and BZ#15105 still applied. It fixes BZ #21029, although it is marked as duplicated of #20729 (I reopened to track this cleanup). [BZ #21029] * config.h.in [CAN_USE_REGISTER_ASM_EBP]: New define. * sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = elf] (sysdep-dl-routines): Add libc-do-syscall. (uses-6-syscall-arguments): Remove. [$(subdir) = misc] (CFLAGS-epoll_pwait.o): Likewise. [$(subdir) = misc] (CFLAGS-epoll_pwait.os): Likewise. [$(subdir) = misc] (CFLAGS-mmap.o): Likewise. [$(subdir) = misc] (CFLAGS-mmap.os): Likewise. [$(subdir) = misc] (CFLAGS-mmap64.o): Likewise. [$(subdir) = misc] (CFLAGS-mmap64.os): Likewise. [$(subdir) = misc] (CFLAGS-pselect.o): Likewise. [$(subdir) = misc] (cflags-pselect.o): Likewise. [$(subdir) = misc] (cflags-pselect.os): Likewise. [$(subdir) = misc] (cflags-rtld-mmap.os): Likewise. [$(subdir) = sysvipc] (cflags-semtimedop.o): Likewise. [$(subdir) = sysvipc] (cflags-semtimedop.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fadvise64.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fadvise64.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate64.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate64.os): Likewise. [$(subdir) = io] (CFLAGS-sync_file_range.o): Likewise. [$(subdir) = io] (CFLAGS-sync_file_range.os): Likewise. [$(subdir) = io] (CFLAGS-fallocate.o): Likewise. [$(subdir) = io] (CFLAGS-fallocate.os): Likewise. [$(subdir) = io] (CFLAGS-fallocate64.o): Likewise. [$(subdir) = io] (CFLAGS-fallocate64.os): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.o): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.os): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.o): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.os): Likewise. [$(subdir) = nptl] (CFLAGS-sem_wait.o): Likewise. [$(subdir) = nptl] (CFLAGS-sem_wait.os): Likewise. [$(subdir) = nptl] (CFLAGS-sem_timedwait.o): Likewise. [$(subdir) = nptl] (CFLAGS-sem_timedwait.os): Likewise. * sysdeps/unix/sysv/linux/i386/configure.ac: Add check if compiler allows ebp on inline assembly. * sysdeps/unix/sysv/linux/i386/configure: Regenerate. * sysdeps/unix/sysv/linux/i386/sysdep.h (OPTIMIZE_FOR_GCC_5): Set if CAN_USE_REGISTER_ASM_EBP is set. (check_consistency): Likewise. 2017-01-08 13:38:23 +00:00			`# Check if CFLAGS allows compiler to use ebp register in inline assembly.`
			`AC_CACHE_CHECK([if compiler flags allows ebp in inline assembly],`
			`libc_cv_can_use_register_asm_ebp, [`
			`AC_COMPILE_IFELSE(`
			`[AC_LANG_PROGRAM([`
			`void foo (int i)`
			`{`
			`register int reg asm ("ebp") = i;`
			`asm ("# %0" : : "r" (reg));`
			`}])],`
			`[libc_cv_can_use_register_asm_ebp=yes],`
			`[libc_cv_can_use_register_asm_ebp=no])`
			`])`
			`if test $libc_cv_can_use_register_asm_ebp = yes; then`
			`AC_DEFINE(CAN_USE_REGISTER_ASM_EBP)`
			`fi`

Move architecture cases out of sysdeps/unix/sysv/linux/configure.ac. Continuing the process of making non-ex-ports architectures follow the preferred sysdeps practices followed by ex-ports architectures - that is, putting things in architecture-specific sysdeps files rather than having architecture-specific cases in architecture-independent files - this patch moves architecture cases out of sysdeps/unix/sysv/linux/configure.ac into (new or existing) configure fragments for each architecture. (In the case of the arch_minimum_kernel setting for x32, sysdeps/unix/sysv/linux/x86_64/x32/configure already has such a setting so the setting in sysdeps/unix/sysv/linux/configure.ac was a duplicate that could just be removed - though I haven't tested for x32.) Tested for x86_64 and x86 that the patch causes no changes to the installed shared libraries or ldd (or any part of the installation except for the parts that always change because the files contain timestamps - nscd and static libraries). * sysdeps/unix/sysv/linux/configure.ac: Remove cases for individual architectures. * sysdeps/unix/sysv/linux/configure: Regenerated. * sysdeps/unix/sysv/linux/i386/configure.ac: New file. * sysdeps/unix/sysv/linux/i386/configure: New generated file. * sysdeps/unix/sysv/linux/powerpc/configure.ac (ldd_rewrite_script): Define variable. * sysdeps/unix/sysv/linux/powerpc/configure: Regenerated. * sysdeps/unix/sysv/linux/powerpc/powerpc32/configure.ac: New file. * sysdeps/unix/sysv/linux/powerpc/powerpc32/configure: New generated file. * sysdeps/unix/sysv/linux/s390/configure.ac: New file. * sysdeps/unix/sysv/linux/s390/configure: New generated file. * sysdeps/unix/sysv/linux/sh/configure.ac: New file. * sysdeps/unix/sysv/linux/sh/configure: New generated file. * sysdeps/unix/sysv/linux/sparc/configure.ac: New file. * sysdeps/unix/sysv/linux/sparc/configure: New generated file. * sysdeps/unix/sysv/linux/x86_64/configure.ac: New file. * sysdeps/unix/sysv/linux/x86_64/configure: New generated file. 2014-06-24 20:53:03 +00:00			`libc_cv_gcc_unwind_find_fde=yes`
			`ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed`