The configure script checks for -mlong-double-128 but mentions -mlongdouble
when it fails.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
GCC 7.5.0 (PR94200) will refuse to compile if both -mabi=% and
-mlong-double-128 are passed on the command line. Surprisingly,
it will work happily if the latter is not. For the sake of
maintaining status quo, test for and blacklist such compilers.
Tested with a GCC 8.3.1 and GCC 7.5.0 compiler for ppc64le.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
This is a small step up from 2.25 which brings in support for
rewriting the .gnu.attributes section of libc/libm.so.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Add compiler feature tests to ensure we can build ieee128 long double.
These test for -mabi=ieeelongdouble, -mno-gnu-attribute, and -Wno-psabi.
Likewise, verify some compiler bugs have been addressed. These aren't
helpful for building glibc, but may cause test failures when testing
the new long double. See notes below from Raji.
On powerpc64le, some older compiler versions give error for the function
signbit() for 128-bit floating point types. This is fixed by PR83862
in gcc 8.0 and backported to gcc6 and gcc7. This patch adds a test
to check compiler version to avoid compiler errors during make check.
Likewise, test for -mno-gnu-attribute support which was
On powerpc64le, a few files are built on IEEE long double mode
(-mabi=ieeelongdouble), whereas most are built on IBM long double mode
(-mabi=ibmlongdouble, the default for -mlong-double-128). Since binutils
2.31, linking object files with different long double modes causes
errors similar to:
ld: libc_pic.a(s_isinfl.os) uses IBM long double,
libc_pic.a(ieee128-qefgcvt.os) uses IEEE long double.
collect2: error: ld returned 1 exit status
make[2]: *** [../Makerules:649: libc_pic.os] Error 1
The warnings are fair and correct, but in order for glibc to have
support for both long double modes on powerpc64le, they have to be
ignored. This can be accomplished with the use of -mno-gnu-attribute
option when building the few files that require IEEE long double mode.
However, -mno-gnu-attribute is not available in GCC 6, the minimum
version required to build glibc, so this patch adds a test for this
feature in powerpc64le builds, and fails early if it's not available.
Co-Authored-By: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
Co-Authored-By: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
The configure fragment for powerpc64le contains a test for the presence
of several compiler builtins and of the __float128 type, which are
provided by GCC 6.2 for powerpc64le. Since this configure test was
added, the compiler version required to build glibc for powerpc64le was
different than that required for the other architectures.
Now that glibc requires GCC 6.2 globally (since commit ID 4dcbbc3b28),
this patch removes the powerpc64le-specific test.
Even tough the configure test checks for compiler features rather than
compiler version, the intent of the test was to stop build attempts at
early stages, if they had been configured with a too old compiler. It
was not the intention of the test to detect compiler breakage (such as
the removal of the required compiler features in future GCC versions),
and glibc is not the place to test for compiler regressions, anyway.
Tested for powerpc64le with GCC 6.2 (built with build-many-glibcs.py).
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
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.
