Date: Wed, 25 Jan 2017 17:27:44 -0800 From: Mark Millard <markmi@dsl-only.net> To: FreeBSD Toolchain <freebsd-toolchain@freebsd.org>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: 3.9.1's lld and powerpc64 for -pie use: can't create dynamic relocation R_PPC64_REL24 against readonly segment Message-ID: <2C07C1E1-4549-43CC-BF23-A83CEE090448@dsl-only.net> In-Reply-To: <5FF1F3C4-E169-4967-9B08-F97A52B33E6F@dsl-only.net> References: <5FF1F3C4-E169-4967-9B08-F97A52B33E6F@dsl-only.net>
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On 2017-Jan-21, at 2:16 PM, Mark Millard <markmi at dsl-only.net> wrote:
> For:
>=20
> # more main.c =
=
static volatile =
char big_area[67001] =3D "This is a test";
>=20
> int main ()
> {
> big_area[67000] =3D '9';
> }
>=20
> I get (the -fPIE is not required for the behavior):
>=20
> # clang -fuse-ld=3Dlld -Wl,-t -pie -fPIE main.c
> /usr/lib/Scrt1.o
> /usr/lib/crti.o
> /usr/lib/crtbeginS.o
> /tmp/main-c6f752.o
> /usr/lib/libgcc_s.so
> /lib/libc.so.7
> /usr/lib/libgcc_s.so
> /usr/lib/crtendS.o
> /usr/lib/crtn.o
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> can't create dynamic relocation R_PPC64_REL24 against readonly segment
> clang: error: linker command failed with exit code 1 (use -v to see =
invocation)
>=20
> (This is difficult to study because it does not leave even a
> partial a.out and it does not report the specifics of what
> segment or what symbol or the like.)
>=20
> Even an empty source produces that, but also including the
> expected:
>=20
> undefined symbol: main in /usr/lib/Scrt1.o
>=20
> It appears that the R_PPC64_REL24's are some subset of. . .
>=20
> /usr/lib/Scrt1.o :
>=20
> 00000000000000cc R_PPC64_REL24 atexit
> 00000000000000d8 R_PPC64_REL24 _init_tls
> 00000000000000f8 R_PPC64_REL24 atexit
> 00000000000001b4 R_PPC64_REL24 _init
> 0000000000000240 R_PPC64_REL24 main
> 0000000000000248 R_PPC64_REL24 exit
> 00000000000002fc R_PPC64_REL24 _fini
>=20
> (That would be 6 by ignoring main, matching
> the message count.)
>=20
> /usr/lib/crtbeginS.o :
>=20
> 0000000000000040 R_PPC64_REL24 __cxa_finalize
> 0000000000000000 R_PPC64_REL24 .opd
> 0000000000000000 R_PPC64_REL24 .opd+0x0000000000000018
>=20
> /usr/lib/crtendS.o :
>=20
> 0000000000000000 R_PPC64_REL24 .opd
>=20
> main.o , if I have it produced, does not have R_PPC64_REL24
> in it.
I have submitted this as llvm bugzilla 31762 and added
it to llvm bugzilla 25780's Depends On list (the meta
submittal for using clang and [its toolchain] as the
FreeBSD powerpc and powerpc64 system compiler [and
toolchain]).
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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