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authorJoseph Myers <joseph@codesourcery.com>2017-12-12 13:56:47 +0000
committerJoseph Myers <joseph@codesourcery.com>2017-12-12 13:56:47 +0000
commit8df5d34720dd71e934545bade879e04697830757 (patch)
treeaf607d1b63037ad92901e4ed8a4a71f95270ee31 /config.make.in
parent0cee1257a96fc2983c7cc0717015ad54d81ceff3 (diff)
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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 'config.make.in')
-rw-r--r--config.make.in2
1 files changed, 1 insertions, 1 deletions
diff --git a/config.make.in b/config.make.in
index 9da77d1efa..04513dbb74 100644
--- a/config.make.in
+++ b/config.make.in
@@ -57,7 +57,7 @@ have-z-execstack = @libc_cv_z_execstack@
 have-protected-data = @libc_cv_protected_data@
 have-insert = @libc_cv_insert@
 have-glob-dat-reloc = @libc_cv_has_glob_dat@
-with-fp = @with_fp@
+with-fp = @libc_cv_with_fp@
 enable-timezone-tools = @enable_timezone_tools@
 unwind-find-fde = @libc_cv_gcc_unwind_find_fde@
 have-fpie = @libc_cv_fpie@