glibc/sysdeps/mips/preconfigure
Joseph Myers 8df5d34720 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.
2017-12-12 13:56:47 +00:00

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case "$machine" in
mips*)
abiflag=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define _MIPS_SIM \(.*\)/\1/p'`
mips16flag=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define __mips16 \(.*\)/\1/p'`
base_machine=mips
if test "$abiflag" = "_ABIO32" ; then
if test "$mips16flag" = "1" ; then
machine=mips/mips32/mips16
else
machine=mips/mips32
fi
elif test "$abiflag" = "_ABIN32" ; then
machine=mips/mips64/n32
elif test "$abiflag" = "_ABI64" ; then
machine=mips/mips64/n64
else
as_fn_error $? "Unable to determine ABI." "$LINENO" 5
fi
# $config_machine is not really needed here but the slash after
# $machine is needed by the case statement in
# sysdeps/unix/sysv/linux/mips/configure.ac.
machine=$machine/$config_machine
if test "$abiflag" != "_ABIO32" -a "$mips16flag" = "1"; then
as_fn_error $? "MIPS16 is only supported with the o32 ABI." "$LINENO" 5
fi
with_fp_cond="defined __mips_hard_float"
;;
esac