Re: [PATCH] arm: Support -mfdpic for more targets

[Fangrui Song <maskray@google.com>]

On Wed, Mar 6, 2024 at 1:54 AM Richard Earnshaw (lists)
<Richard.Earnshaw@arm.com> wrote:
>
> On 06/03/2024 05:07, Fangrui Song wrote:
> > On Fri, Feb 23, 2024 at 7:33 PM Fangrui Song <maskray@google.com> wrote:
> >>
> >> From: Fangrui Song <maskray@gcc.gnu.org>
> >>
> >> Targets that are not arm*-*-uclinuxfdpiceabi can use -S -mfdpic, but -c
> >> -mfdpic does not pass --fdpic to gas.  This is an unnecessary
> >> restriction.  Just define the ASM_SPEC in bpabi.h.
> >>
> >> Additionally, use armelf[b]_linux_fdpiceabi emulations for -mfdpic in
> >> linux-eabi.h.  This will allow a future musl fdpic port to use the
> >> desired BFD emulation.
> >>
> >> gcc/ChangeLog:
> >>
> >>         * config/arm/bpabi.h (TARGET_FDPIC_ASM_SPEC): Transform -mfdpic.
> >>         * config/arm/linux-eabi.h (TARGET_FDPIC_LINKER_EMULATION): Define.
> >>         (SUBTARGET_EXTRA_LINK_SPEC): Use TARGET_FDPIC_LINKER_EMULATION
> >>         if -mfdpic.
> >> ---
> >>  gcc/config/arm/bpabi.h      | 2 +-
> >>  gcc/config/arm/linux-eabi.h | 5 ++++-
> >>  2 files changed, 5 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/gcc/config/arm/bpabi.h b/gcc/config/arm/bpabi.h
> >> index 7a279f3ed3c..6778be1a8bf 100644
> >> --- a/gcc/config/arm/bpabi.h
> >> +++ b/gcc/config/arm/bpabi.h
> >> @@ -55,7 +55,7 @@
> >>  #define TARGET_FIX_V4BX_SPEC " %{mcpu=arm8|mcpu=arm810|mcpu=strongarm*"\
> >>    "|march=armv4|mcpu=fa526|mcpu=fa626:--fix-v4bx}"
> >>
> >> -#define TARGET_FDPIC_ASM_SPEC ""
> >> +#define TARGET_FDPIC_ASM_SPEC "%{mfdpic: --fdpic}"
> >>
> >>  #define BE8_LINK_SPEC                                                  \
> >>    "%{!r:%{!mbe32:%:be8_linkopt(%{mlittle-endian:little}"               \
> >> diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
> >> index eef791f6a02..0c5c58e4928 100644
> >> --- a/gcc/config/arm/linux-eabi.h
> >> +++ b/gcc/config/arm/linux-eabi.h
> >> @@ -46,12 +46,15 @@
> >>  #undef  TARGET_LINKER_EMULATION
> >>  #if TARGET_BIG_ENDIAN_DEFAULT
> >>  #define TARGET_LINKER_EMULATION "armelfb_linux_eabi"
> >> +#define TARGET_FDPIC_LINKER_EMULATION "armelfb_linux_fdpiceabi"
> >>  #else
> >>  #define TARGET_LINKER_EMULATION "armelf_linux_eabi"
> >> +#define TARGET_FDPIC_LINKER_EMULATION "armelf_linux_fdpiceabi"
> >>  #endif
> >>
> >>  #undef  SUBTARGET_EXTRA_LINK_SPEC
> >> -#define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
> >> +#define SUBTARGET_EXTRA_LINK_SPEC " -m %{mfdpic: " \
> >> +  TARGET_FDPIC_LINKER_EMULATION ";:" TARGET_LINKER_EMULATION "}"
> >>
> >>  /* GNU/Linux on ARM currently supports three dynamic linkers:
> >>     - ld-linux.so.2 - for the legacy ABI
> >> --
> >> 2.44.0.rc1.240.g4c46232300-goog
> >>
> >
> > Ping:)
> >
>
> We're in stage4 at present and this is new material.  I'll look at it after the branch has been cut.
>
> R.

refs/heads/releases/gcc-14 has been cut :)



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