Bug#944736: gcc-9 doesn't link properly when using ld.bfd

[Gilles Crèvecœur <gilles.crevecoeur@gmail.com>]

Package: gcc-9
Version: 9.2.1-19
Severity: important

Dear Maintainer,

When compiling this short example:

/* a.c begins here */
#include <stdio.h>
#include <gmp.h>

int main(void) {
  mpf_t  y;
  mpf_init2(y, 128);
  mpf_sqrt_ui(y, 2UL);
  gmp_printf("%.*Ff\n", 38, y);
  return 0;
}
/* a.c ends here */

with the command :
     $ gcc -lgmp a.c

gcc produces this error:
    /usr/bin/ld: /tmp/cclW7Wdd.o: in function `main':
    a.c:(.text+0x15): undefined reference to `__gmpf_init2'
    /usr/bin/ld: a.c:(.text+0x26): undefined reference to `__gmpf_sqrt_ui'
    /usr/bin/ld: a.c:(.text+0x43): undefined reference to `__gmp_printf'
    collect2: error: ld returned 1 exit status

Notice, libgmp is installed, according to this commands:
        $ apt-cache policy libgmp-dev
returns:
  libgmp-dev:
  Installed: 2:6.1.2+dfsg-4
  Candidate: 2:6.1.2+dfsg-4
  Version table:
  *** 2:6.1.2+dfsg-4 900
        900 https://deb.debian.org/debian sid/main amd64 Packages
        100 /var/lib/dpkg/status

But that works as exepected when compiling with clang, and with gcc-8.
That also works with the command:
     $ gcc -fuse-ld=gold -lgmp a.c
It was also successful when I tried with lld from the package lld-8.

I have obtained the same results with th following snippets:
/* b.c begins here */
#include <glib.h>

int main(void) {
  gchar *str="Just a string";
  gchar *str2;
  str2 = g_strdup(str);
  return 0;
}
/* b.c ends here */
I compiled the latter with:
     $ gcc $(pkg-configs --cflags --libs glib-2.0) b.c
which returns:
    /usr/bin/ld: /tmp/ccuQaGQ7.o: in function `main':
    b.c:(.text+0x1b): undefined reference to `g_strdup'
    collect2: error: ld returned 1 exit status

But that linked properly with ld.gold and lld-8.

I can't figure out how to correct this issue. One can
symlinks /usr/bin/ld to /usr/bin/ld.gold to not have to pass
--fuse-ld=gold, but this is twisted. The default bfd linker should
work.

Cheers
--
Gilles Crèvecœur



-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (900, 'unstable'), (100, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.3.1-e1 (SMP w/2 CPU cores; PREEMPT)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE=fr (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gcc-9 depends on:
ii  binutils      2.33.1-2
ii  cpp-9         9.2.1-19
ii  gcc-9-base    9.2.1-19
ii  libc6         2.29-3
ii  libcc1-0      9.2.1-19
ii  libgcc-9-dev  9.2.1-19
ii  libgcc1       1:9.2.1-19
ii  libgmp10      2:6.1.2+dfsg-4
ii  libisl21      0.21-2
ii  libmpc3       1.1.0-1
ii  libmpfr6      4.0.2-1
ii  libstdc++6    9.2.1-19
ii  zlib1g        1:1.2.11.dfsg-1+b1

Versions of packages gcc-9 recommends:
ii  libc6-dev  2.29-3

Versions of packages gcc-9 suggests:
ii  gcc-9-doc         9.2.0-1
ii  gcc-9-locales     9.2.1-19
pn  gcc-9-multilib    <none>
pn  libasan5-dbg      <none>
pn  libatomic1-dbg    <none>
pn  libgcc1-dbg       <none>
pn  libgomp1-dbg      <none>
pn  libitm1-dbg       <none>
pn  liblsan0-dbg      <none>
pn  libquadmath0-dbg  <none>
pn  libtsan0-dbg      <none>
pn  libubsan1-dbg     <none>

-- no debconf information