The creation of the divergent sysdeps directory for powerpc64le
commit 2f7f3cd8cd
Author: Paul E. Murphy <murphyp@linux.vnet.ibm.com>
Date: Fri Jul 15 18:04:40 2016 -0500
powerpc64le: Create divergent sysdep directory for powerpc64le.
allowed float128 to be enabled for powerpc64le (little-endian) and not
for powerpc64 (big-endian). Since the only intended difference between
them was the presence or absence of the float128 interface, the sysdeps
directory for powerpc64le explicitly reused the files from powerpc64
(through the use of Implies files).
Although this works, it also means that files under the powerpc64
directory might be preferred over files under powerpc64le. For
instance, on a build for powerpc64le with target set to power9, a file
from powerpc64/power5 might get built, even though a file with the same
name exists in powerpc64le/power8. That happens because the processor
hierarchy was only defined in the sysdeps directory for powerpc64 (and
borrowed by powerpc64le).
This patch fixes this behavior, by creating new subdirectories under
powerpc64 (i.e.: powerpc64/be and powerpc64/le) and creating new Implies
files to provide the hierarchy of processors for powerpc64 and
powerpc64le separately. These changes have no effect on installed,
stripped binaries (which remain unchanged).
Tested that installed stripped binaries are unchanged and that there are
no regressions on powerpc64 and powerpc64le.
There is a configure option --without-fp that specifies that nofpu
sysdeps directories should be used instead of fpu directories.
For most glibc configurations, this option is of no use: either there
is no valid nofpu variant of that configuration, or there are no fpu
or nofpu sysdeps directories for that processor and so the option does
nothing. For a few configurations, if you are using a soft-float
compiler this option is required, and failing to use it generally
results in compilation errors from inline asm using unavailable
floating-point instructions.
We're moving away from --with-cpu to configuring glibc based on how
the compiler generates code, and it is natural to do so for
--without-fp as well; in most cases the soft-float and hard-float ABIs
are incompatible so you have no hope of building a working glibc with
an inappropriately configured compiler or libgcc.
This patch eliminates --without-fp, replacing it entirely by automatic
configuration based on the compiler. Configurations for which this is
relevant (coldfire / mips / powerpc32 / sh) define a variable
with_fp_cond in their preconfigure fragments (under the same
conditions under which those fragments do anything); this is a
preprocessor conditional which the toplevel configure script then uses
in a test to determine which sysdeps directories to use.
The config.make with-fp variable remains. It's used only by powerpc
(sysdeps/powerpc/powerpc32/Makefile) to add -mhard-float to various
flags variables. For powerpc, -mcpu= options can imply use of
soft-float. That could be an issue if you want to build for
e.g. 476fp, but are using --with-cpu=476 because there isn't a 476fp
sysdeps directory. If in future we eliminate --with-cpu and replace
it entirely by testing the compiler, it would be natural at that point
to eliminate that code as well (as the user should then just use a
compiler defaulting to 476fp and the 476 sysdeps directory would be
used automatically).
Tested for x86_64, and tested with build-many-glibcs.py that installed
shared libraries are unchanged by this patch.
* configure.ac (--with-fp): Remove configure option.
(with_fp_cond): New variable.
(libc_cv_with_fp): New configure test. Use this variable instead
of with_fp.
* configure: Regenerated.
* config.make.in (with-fp): Use @libc_cv_with_fp@.
* manual/install.texi (Configuring and compiling): Remove
--without-fp.
* INSTALL: Regenerated.
* sysdeps/m68k/preconfigure (with_fp_cond): Define for ColdFire.
* sysdeps/mips/preconfigure (with_fp_cond): Define.
* sysdeps/powerpc/preconfigure (with_fp_cond): Define for 32-bit.
* sysdeps/sh/preconfigure (with_fp_cond): Define.
* scripts/build-many-glibcs.py (Context.add_all_configs): Do not
use --without-fp to configure glibc.
float128 on powerpc64le requires the addition of the ieee754/float128
sysdep, whereas powerpc64 doesn't. This requires creating a bunch of
submachine and cpu directories and Implies files which just point
towards their powerpc64 equivalent.
Tested on P7, P8, and generic powerpc64le targets with and without
multiarch.
* sysdeps/powerpc/powerpc64le/Implies: New file.
* sysdeps/powerpc/powerpc64le/fpu/Implies: New file.
* sysdeps/powerpc/powerpc64le/fpu/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power7/Implies: New file.
* sysdeps/powerpc/powerpc64le/power7/fpu/Implies: New file.
* sysdeps/powerpc/powerpc64le/power7/fpu/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power7/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power8/Implies: New file.
* sysdeps/powerpc/powerpc64le/power8/fpu/Implies: New file.
* sysdeps/powerpc/powerpc64le/power8/fpu/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power8/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power9/Implies: New file.
* sysdeps/powerpc/powerpc64le/power9/fpu/Implies: New file.
* sysdeps/powerpc/powerpc64le/power9/fpu/multiarch/Implies: New file.
* sysdeps/powerpc/powerpc64le/power9/multiarch/Implies: New file.
* sysdeps/powerpc/preconfigure: New file.
* sysdeps/unix/sysv/linux/powerpc/powerpc64le/Implies: New file.
* sysdeps/unix/sysv/linux/powerpc/powerpc64le/fpu/Implies: New file.
This patch makes non-ex-ports architectures set base_machine and
machine based on the original configured machine value in preconfigure
fragments, like ex-ports architectures, rather than in the toplevel
configure.ac.
Tested x86 that the disassembly of installed shared libraries is
unchanged by the patch.
* configure.ac (base_machine): Do not set specially for particular
machines here.
* configure: Regenerated.
* sysdeps/powerpc/preconfigure: Move machine and base_machine
settings from configure.ac.
* sysdeps/i386/preconfigure: New file.
* sysdeps/s390/preconfigure: Likewise.
* sysdeps/sh/preconfigure: Likewise.
* sysdeps/sparc/preconfigure: Likewise.
