[Bug driver/52556] New: Ability to change GLIBC_DYNAMIC_LINKER

[Bug driver/52556] New: Ability to change GLIBC_DYNAMIC_LINKER

[christer.solskogen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

             Bug #: 52556
           Summary: Ability to change GLIBC_DYNAMIC_LINKER
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: driver
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: christer.solskogen@gmail.com


I would love to be able to change GLIBC_DYNAMIC_LINKER to something other than
default without changing the source code. This is useful if you want to create
a completly standalone toolchain with binutils, gcc and some kind of libc.

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[christer.solskogen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

--- Comment #1 from Christer Solskogen <christer.solskogen at gmail dot com> 2012-03-11 12:54:45 UTC ---
I see now that the google gcc branch is having this kind of ability. Any plans
of integrating them?

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-11 14:14:28 UTC ---
Just use -Wl,-dynamic-linker=/whatever/ld.so or you could use --with-specs
configure option.

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[christer.solskogen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

--- Comment #3 from Christer Solskogen <christer.solskogen at gmail dot com> 2012-03-11 15:50:57 UTC ---
I could, but is not a sexy(*) as --with-runtime-root-prefix :-)

*) http://patchwork.ozlabs.org/patch/80538/

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[heroxbd at sohu dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

Benda Xu <heroxbd at sohu dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |heroxbd at sohu dot com

--- Comment #4 from Benda Xu <heroxbd at sohu dot com> ---
(In reply to Jakub Jelinek from comment #2)
> Just use -Wl,-dynamic-linker=/whatever/ld.so 

-Wl,-dynamic-linker=/whatever/ld.so cannot be set permanently. It requires a
wrapper to inject such argument all the time, which is ugly.

> or you could use --with-specs configure option.

Builtin specs of GCC is already very complicated (output from gcc-4.7.3
-dumpspecs on amd64):

...

*link:
%{!static:--eh-frame-hdr} %{m32|mx32:;:-m elf_x86_64}                   
%{m32:-m elf_i386}                    %{mx32:-m elf32_x86_64}  
%{shared:-shared}   %{!shared:     %{!static:       %{rdynamic:-export-dynamic}
      %{m32:-dynamic-linker
%{muclibc:/lib/ld-uClibc.so.0;:%{mbionic:/system/bin/linker;:/lib/ld-linux.so.2}}}
      %{m32|mx32:;:-dynamic-linker
%{muclibc:/lib/ld64-uClibc.so.0;:%{mbionic:/system/bin/linker64;:/lib64/ld-linux-x86-64.so.2}}}
      %{mx32:-dynamic-linker
%{muclibc:/lib/ldx32-uClibc.so.0;:%{mbionic:/system/bin/linkerx32;:/libx32/ld-linux-x32.so.2}}}}
    %{static:-static}}

...

writing an equivalent specs with prefixed dynamic linker is horrible.

Please consider sopport dynamic linker prefix by an extra configure option.

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[heroxbd at sohu dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

--- Comment #5 from Benda Xu <heroxbd at sohu dot com> ---
Dear Jakub,

I find your comment misleading for the --with-specs option.

It sets CONFIGURE_SPECS macro, which is used in gcc.c as

static const char *const driver_self_specs[] = {
  "%{fdump-final-insns:-fdump-final-insns=.} %<fdump-final-insns",
  DRIVER_SELF_SPECS, CONFIGURE_SPECS, GOMP_SELF_SPECS, GTM_SELF_SPECS
};

so it is a list of specs for the driver *itself*, should not be used to specify
link spec.

If you mean passing --with-specs="-Wl,-dynamic-linker=/whatever/ld.so" to
configure, it is broken in multilib cases.

Therefore we lack of a convenient way to specify a default alternative location
of the dynamic linker.

Benda

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[brooks at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

Brooks Moses <brooks at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |brooks at gcc dot gnu.org

--- Comment #6 from Brooks Moses <brooks at gcc dot gnu.org> ---
Richard Biener mentioned that Red Hat has "a local patch that allows amending
link_spec from an external file, which would sound more flexible" here:
http://patchwork.ozlabs.org/patch/80538/

It's not completely clear whether it applies to this case, however; he
mentioned that it could be used to produce the equivalent of a -Wl,-rpath=...
option.  The Google-branch change that Christer mentions adds a
-dynamic-linker=... option to the link spec rather than an -rpath option -- I
would guess that the patch Richard mentions could cover that as well, but I'm
not sure.

[Bug driver/52556] Ability to change GLIBC_DYNAMIC_LINKER

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52556

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |hdante at gmail dot com

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 111084 has been marked as a duplicate of this bug. ***