Re: [ARM/FDPIC v5 03/21] [ARM] FDPIC: Force FDPIC related options unless -mno-fdpic is provided

[Christophe Lyon <christophe.lyon@linaro.org>]

On Tue, 16 Jul 2019 at 12:34, Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> Christophe Lyon <christophe.lyon@st.com> writes:
> > On 22/05/2019 10:45, Christophe Lyon wrote:
> >> On Wed, 22 May 2019 at 10:39, Szabolcs Nagy <Szabolcs.Nagy@arm.com> wrote:
> >>>
> >>> On 21/05/2019 16:28, Christophe Lyon wrote:
> >>>> --- a/gcc/config/arm/linux-eabi.h
> >>>> +++ b/gcc/config/arm/linux-eabi.h
> >>>> @@ -89,7 +89,7 @@
> >>>>   #define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
> >>>>   #endif
> >>>>   #define MUSL_DYNAMIC_LINKER \
> >>>> -  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
> >>>> +  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E
> >>>> "%{mfloat-abi=hard:hf}%{mfdpic:-fdpic}.so.1"
> >>>
> >>> the line break seems wrong (either needs \ or no newline)
> >>>
> >> Sorry, that's a mailer artifact.
> >>
> >>>> --- a/libsanitizer/configure.tgt
> >>>> +++ b/libsanitizer/configure.tgt
> >>>> @@ -45,7 +45,7 @@ case "${target}" in
> >>>>          ;;
> >>>>     sparc*-*-solaris2.11*)
> >>>>          ;;
> >>>> -  arm*-*-uclinuxfdpiceabi)
> >>>> +  arm*-*-fdpiceabi)
> >>>
> >>> should be *fdpiceabi instead of *-fdpiceabi i think.
> >>
> >> Indeed, thanks
> >> .
> >>
> > FWIW, here is the updated patch:
> > - handles musl -fdpic suffix
> > - disables sanitizers for arm*-*-fdpiceabi
> > - does not handle -static in a special way, so using -static produces binaries that request the non-existing /usr/lib/ld.so.1, thus effectively making -static broken/unsupported (this does lead to a few more FAIL in the testsuite)
> >
> > The plan is to work -static-pie later, as discussed.
>
> Could you make -static without -mno-fdpic an error via a %e spec,
> so that the failure mode is a bit more user-friendly?
>

Sure.
Do you know if there is a way to catch linker options in the specs?
Would it be possible to still accept -static -Wl,-dynamic-linker XXX ?

> I realise this isn't your preferred option, sorry.
>
> > diff --git a/gcc/config/arm/bpabi.h b/gcc/config/arm/bpabi.h
> > index e1bacf4..6c25a1a 100644
> > --- a/gcc/config/arm/bpabi.h
> > +++ b/gcc/config/arm/bpabi.h
> > @@ -55,6 +55,8 @@
> >  #define TARGET_FIX_V4BX_SPEC " %{mcpu=arm8|mcpu=arm810|mcpu=strongarm*"\
> >    "|march=armv4|mcpu=fa526|mcpu=fa626:--fix-v4bx}"
> >
> > +#define TARGET_FDPIC_ASM_SPEC  ""
>
> Formatting nit: should be a single space before ""
>
> > +
> >  #define BE8_LINK_SPEC                                                        \
> >    "%{!r:%{!mbe32:%:be8_linkopt(%{mlittle-endian:little}"             \
> >    "                         %{mbig-endian:big}"                      \
> > @@ -64,7 +66,7 @@
> >  /* Tell the assembler to build BPABI binaries.  */
> >  #undef  SUBTARGET_EXTRA_ASM_SPEC
> >  #define SUBTARGET_EXTRA_ASM_SPEC \
> > -  "%{mabi=apcs-gnu|mabi=atpcs:-meabi=gnu;:-meabi=5}" TARGET_FIX_V4BX_SPEC
> > +  "%{mabi=apcs-gnu|mabi=atpcs:-meabi=gnu;:-meabi=5}" TARGET_FIX_V4BX_SPEC TARGET_FDPIC_ASM_SPEC
>
> Long line.
>
> > diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
> > index 66ec0ea..d7cc923 100644
> > --- a/gcc/config/arm/linux-eabi.h
> > +++ b/gcc/config/arm/linux-eabi.h
> > @@ -89,7 +89,7 @@
> >  #define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
> >  #endif
> >  #define MUSL_DYNAMIC_LINKER \
> > -  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
> > +  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}%{mfdpic:-fdpic}.so.1"
> >
> >  /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
> >     use the GNU/Linux version, not the generic BPABI version.  */
>
> Rich, could you confirm that this is (going to be?) the correct name?
>
> > diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
> > index 66ec0ea..d7cc923 100644
> > --- a/gcc/config/arm/linux-eabi.h
> > +++ b/gcc/config/arm/linux-eabi.h
> > @@ -89,7 +89,7 @@
> >  #define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
> >  #endif
> >  #define MUSL_DYNAMIC_LINKER \
> > -  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
> > +  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}%{mfdpic:-fdpic}.so.1"
> >
> >  /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
> >     use the GNU/Linux version, not the generic BPABI version.  */
> > @@ -101,11 +101,14 @@
> >  #undef  ASAN_CC1_SPEC
> >  #define ASAN_CC1_SPEC "%{%:sanitize(address):-funwind-tables}"
> >
> > +#define FDPIC_CC1_SPEC ""
> > +
> >  #undef  CC1_SPEC
> >  #define CC1_SPEC                                                     \
> > -  LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC,   \
> > +  LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC " "        \
> > +                    FDPIC_CC1_SPEC,                                  \
> >                      GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC " "   \
> > -                    ANDROID_CC1_SPEC)
> > +                    ANDROID_CC1_SPEC "" FDPIC_CC1_SPEC)
> >
> >  #define CC1PLUS_SPEC \
> >    LINUX_OR_ANDROID_CC ("", ANDROID_CC1PLUS_SPEC)
>
> Does it make sense to add FDPIC_CC1_SPEC to the Android version?

No, I will remove it.

>
> > diff --git a/gcc/config/arm/uclinuxfdpiceabi.h b/gcc/config/arm/uclinuxfdpiceabi.h
> > new file mode 100644
> > index 0000000..3180bcd
> > --- /dev/null
> > +++ b/gcc/config/arm/uclinuxfdpiceabi.h
> > @@ -0,0 +1,52 @@
> > +/* Configuration file for ARM GNU/Linux FDPIC EABI targets.
> > +   Copyright (C) 2018 Free Software Foundation, Inc.
> > +   Contributed by STMicroelectronics.
> > +
> > +   This file is part of GCC.
> > +
> > +   GCC is free software; you can redistribute it and/or modify it
> > +   under the terms of the GNU General Public License as published
> > +   by the Free Software Foundation; either version 3, or (at your
> > +   option) any later version.
> > +
> > +   GCC is distributed in the hope that it will be useful, but WITHOUT
> > +   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
> > +   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
> > +   License for more details.
> > +
> > +   You should have received a copy of the GNU General Public License
> > +   along with GCC; see the file COPYING3.  If not see
> > +   <http://www.gnu.org/licenses/>.  */
> > +
> > +/* On uClibc EABI GNU/Linux, we want to force -mfdpic by default,
> > +   which also means we produce PIE code by default.  */
> > +#undef FDPIC_CC1_SPEC
> > +#define FDPIC_CC1_SPEC \
> > +  "%{!mno-fdpic:-mfdpic %{!no-PIE:%{!fpie:%{!fPIC:%{!fpic: -fPIE}}}}}"
>
> Looks like the !no-PIE should be !fno-PIE.
Indeed.

> > +/* Add --fdpic assembler flag by default.  */
> > +#undef TARGET_FDPIC_ASM_SPEC
> > +#define TARGET_FDPIC_ASM_SPEC  "%{!mno-fdpic: --fdpic}"
>
> Single space before the ".
>

Thanks,

Christophe

> Thanks,
> Richard