diff options
| author | Joseph Myers <joseph@codesourcery.com> | 2017-12-12 13:56:47 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2017-12-12 13:56:47 +0000 |
| commit | 8df5d34720dd71e934545bade879e04697830757 (patch) | |
| tree | af607d1b63037ad92901e4ed8a4a71f95270ee31 /INSTALL | |
| parent | 0cee1257a96fc2983c7cc0717015ad54d81ceff3 (diff) | |
Remove --with-fp / --without-fp.
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.
Diffstat (limited to 'INSTALL')
| -rw-r--r-- | INSTALL | 4 |
1 files changed, 0 insertions, 4 deletions
@@ -81,10 +81,6 @@ will be used, and CFLAGS sets optimization options for the compiler. library will still be usable, but functionality may be lost--for example, you can't build a shared libc with old binutils. -'--without-fp' - Use this option if your computer lacks hardware floating-point - support and your operating system does not emulate an FPU. - '--disable-shared' Don't build shared libraries even if it is possible. Not all systems support shared libraries; you need ELF support and |