Bug#1126055: gcc-15 regression on ppc64el: multiple packages FTBFS with undefined symbol __parse_hwcap_and_convert_at_platform

Package: gcc-15
Version: 15.2.0-12
Severity: serious
Tags: ftbfs
User: [email protected]
Usertags: ppc64el
X-Debbugs-Cc: [email protected], 
[email protected]


Dear GCC Maintainers,

GCC 15 on ppc64el is causing multiple packages FTBFS due to an undefined 
reference to the symbol __parse_hwcap_and_convert_at_platform.

ERROR:

libtool: link: g++  -fPIC -DPIC -shared -nostdlib 
/usr/lib/gcc/powerpc64le-linux-gnu/15/../../../powerpc64le-linux-gnu/crti.o 
/usr/lib/gcc/powerpc64le-linux-gnu/15/crtbeginS.o  
src/sqlite/.libs/libvsqlitepp_la-command.o 
src/sqlite/.libs/libvsqlitepp_la-connection.o 
src/sqlite/.libs/libvsqlitepp_la-savepoint.o 
src/sqlite/.libs/libvsqlitepp_la-execute.o 
src/sqlite/.libs/libvsqlitepp_la-query.o 
src/sqlite/.libs/libvsqlitepp_la-result.o 
src/sqlite/.libs/libvsqlitepp_la-transaction.o 
src/sqlite/.libs/libvsqlitepp_la-view.o   -lsqlite3 
-L/usr/lib/gcc/powerpc64le-linux-gnu/15 
-L/usr/lib/gcc/powerpc64le-linux-gnu/15/../../../powerpc64le-linux-gnu 
-L/usr/lib/gcc/powerpc64le-linux-gnu/15/../../../../lib 
-L/lib/powerpc64le-linux-gnu -L/lib/../lib 
-L/usr/lib/powerpc64le-linux-gnu -L/usr/lib/../lib 
-L/usr/lib/gcc/powerpc64le-linux-gnu/15/../../.. -L/lib -L/usr/lib 
-lstdc++ -lm -lc -lgcc_s /usr/lib/gcc/powerpc64le-linux-gnu/15/crtendS.o 
/usr/lib/gcc/powerpc64le-linux-gnu/15/../../../powerpc64le-linux-gnu/crtn.o 
  -O3 -g -O2 
-ffile-prefix-map=/build/reproducible-path/libvsqlitepp-0.3.13=. 
-fstack-protector-strong -Werror=format-security -Wl,--as-needed 
-Wl,-soname -Wl,libvsqlitepp.so.3 -Wl,-z -Wl,relro -Wl,-z -Wl,now -Wl,-z 
-Wl,defs   -Wl,-soname -Wl,libvsqlitepp.so.3 -o 
.libs/libvsqlitepp.so.3.0.0
/usr/bin/powerpc64le-linux-gnu-ld.bfd: 
/usr/lib/gcc/powerpc64le-linux-gnu/15/libgcc.a(float128-ifunc.o):(.data+0x0): 
undefined reference to `__parse_hwcap_and_convert_at_platform'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:550: libvsqlitepp.la] Error 1
make[2]: Leaving directory 
'/build/reproducible-path/libvsqlitepp-0.3.13'
make[1]: *** [Makefile:700: all-recursive] Error 1
make[1]: Leaving directory 
'/build/reproducible-path/libvsqlitepp-0.3.13'
dh_auto_build: error: make -j8 returned exit code 2
make: *** [debian/rules:24: binary-arch] Error 255
dpkg-buildpackage: error: debian/rules binary-arch subprocess failed 
with exit status 2



ROOT CAUSE:
GCC 15's libgcc.a contains float128-ifunc.o which references 
__parse_hwcap_and_convert_at_platform from glibc (GLIBC_2.23+). The 
symbol exists in libc6-dev 2.42-7, but the dependency is not properly 
declared during linking.


AFFECTED PACKAGES:

libvsqlitepp (0.3.13-4.1)
newmat(1.10.4-9)
tesseract(5.5.0-1)
codeblocks(25.03+dfsg-2)


Build logs of falling packages:
https://buildd.debian.org/status/fetch.php?pkg=libvsqlitepp&arch=ppc64el&ver=0.3.13-4.1%2Bb3&stamp=1768889171&raw=0
https://buildd.debian.org/status/fetch.php?pkg=newmat&arch=ppc64el&ver=1.10.4-9%2Bb1&stamp=1768632273&raw=0
https://buildd.debian.org/status/fetch.php?pkg=tesseract&arch=ppc64el&ver=5.5.0-1%2Bb2&stamp=1768645844&raw=0
https://buildd.debian.org/status/fetch.php?pkg=codeblocks&arch=ppc64el&ver=25.03%2Bdfsg-2%2Bb1&stamp=1768574749&raw=0

These packages previously built successfully with gcc-14.

I tested by adding -Wl,--no-as-needed -lc to LDFLAGS in debian rlues and 
then package (libvsqlitepp) built successfully.

What will be the standard way of resolving this issue ?



Thanks,
Trupti