Darwin linker error "illegal text-relocation" with -shared

Darwin linker error "illegal text-relocation" with -shared

[Ryan S. Elliott]

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Hello,

I would like to see if any progress can be made on the darwin linker error 
reported in 2014 and documented here:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59888

This is a significant problem for the OpenKIM system (https://openkim.org) 
which has many users who would like to use its kim-api package 
(https://github.com/openkim/kim-api) and the associated "Model" codes available 
at openkim.org with macOS.

We have been getting by with a work-around (compile for 32-bit architecture 
"-m32" and use the "-read_only_relocs suppress" command line argument) but now 
we would like to be able to provide precompiled binaries that will work with 
other standard compiled software (i.e., 64-bit, etc.) through the homebrew 
package management system.

Here is the minimal code snippet showing the problem and the compiler/linker 
output.

----------------------------------------------
foo.f90
----------------------------------------------
module foo contains
   subroutine bar
     use, intrinsic :: iso_c_binding
     call gee(c_funloc(gee))
   end subroutine
   subroutine gee(f) bind(c)
     use, intrinsic :: iso_c_binding
     type(c_funptr) :: f
   end subroutine
end module foo
----------------------------------------------

$ gfortran-7 -shared foo.f90
ld: illegal text-relocation to '_gee' in 
/var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccYs60h3.o from 'lC0' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccYs60h3.o for architecture  x86_64
collect2: error: ld returned 1 exit status

$ gfortran-7 --version
GNU Fortran (Homebrew GCC 7.3.0_1) 7.3.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.





Thanks,


Ryan S. Elliott

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module foo
contains
  subroutine bar
    use, intrinsic :: iso_c_binding
    call gee(c_funloc(gee))
  end subroutine
  subroutine gee(f) bind(c)
    use, intrinsic :: iso_c_binding
    type(c_funptr) :: f
  end subroutine
end module foo

Re: Darwin linker error "illegal text-relocation" with -shared

[Thomas Koenig]

Hello Ryan,

> foo.f90
> ----------------------------------------------
> module foo contains
>    subroutine bar
>      use, intrinsic :: iso_c_binding
>      call gee(c_funloc(gee))
>    end subroutine
>    subroutine gee(f) bind(c)
>      use, intrinsic :: iso_c_binding
>      type(c_funptr) :: f
>    end subroutine
> end module foo
> ----------------------------------------------
> 
> $ gfortran-7 -shared foo.f90

You are invoking gfortran without the "-c" option, so it expects to
generate an executable. Yet, you specify "-shared", which only makes
sense for a library, and your source code does not contain a main
program.

What happens if you run

"gfortran -c -shared foo.f90" ?

Re: Darwin linker error "illegal text-relocation" with -shared

[Ryan S. Elliott]

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On Mon, 16 Apr 2018, Thomas Koenig wrote:

> Hello Ryan,
>
>> foo.f90
>> ----------------------------------------------
>> module foo contains
>>    subroutine bar
>>      use, intrinsic :: iso_c_binding
>>      call gee(c_funloc(gee))
>>    end subroutine
>>    subroutine gee(f) bind(c)
>>      use, intrinsic :: iso_c_binding
>>      type(c_funptr) :: f
>>    end subroutine
>> end module foo
>> ----------------------------------------------
>> 
>> $ gfortran-7 -shared foo.f90
>
> You are invoking gfortran without the "-c" option, so it expects to
> generate an executable. Yet, you specify "-shared", which only makes
> sense for a library, and your source code does not contain a main
> program.
>
> What happens if you run
>
> "gfortran -c -shared foo.f90" ?

Hello,  Thanks for your message.

Your suggestion does not generate an error, but only because it does not invoke 
the linker in order to create a shared library.  It just creates a .mod and .o 
file.

In other words, the -c flag overrides the -shared flag.  This is not what I 
want.  I want to create a shared library which is done by the linker.

Ryan

Re: Darwin linker error "illegal text-relocation" with -shared

[Thomas Koenig]

OK, so I haven't played around with shared libraries a lot.

> In other words, the -c flag overrides the -shared flag.  This is not 
> what I want.  I want to create a shared library which is done by the 
> linker.

When I run "gfortran -shared foo.f90" on Linux, I get

/usr/bin/ld: /tmp/ccixEBK9.o: relocation R_X86_64_32 against `.rodata' 
can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Nonrepresentable section on output
collect2: Fehler: ld gab 1 als Ende-Status zurück

whereas "gfortran -shared -fPIC foo.f90" works.

Is it advisable to compile a shared library without position-independent
code?

Re: Darwin linker error "illegal text-relocation" with -shared

[Ryan S. Elliott]

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On Mon, 16 Apr 2018, Thomas Koenig wrote:

> OK, so I haven't played around with shared libraries a lot.
>
>> In other words, the -c flag overrides the -shared flag.  This is not what I 
>> want.  I want to create a shared library which is done by the linker.
>
> When I run "gfortran -shared foo.f90" on Linux, I get
>
> /usr/bin/ld: /tmp/ccixEBK9.o: relocation R_X86_64_32 against `.rodata' can 
> not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: Nonrepresentable section on output
> collect2: Fehler: ld gab 1 als Ende-Status zurück
>
> whereas "gfortran -shared -fPIC foo.f90" works.
>
> Is it advisable to compile a shared library without position-independent
> code?
>

No, you are right.   I should have included the -fPIC flag, but this doesn't 
change the results:


$ gfortran-7 -shared -fPIC foo.f90
ld: illegal text-relocation to '_gee' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o from 'lC0' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o for architecture x86_64
collect2: error: ld returned 1 exit status


As indicated in the subject linek, this is only an issue on macOS (Darwin), it 
all works just fine on linux...


Ryan

Re: Darwin linker error "illegal text-relocation" with -shared

[Steve Kargl]

On Mon, Apr 16, 2018 at 02:51:16PM -0500, Ryan S. Elliott wrote:
> 
> No, you are right.   I should have included the -fPIC flag, but this doesn't 
> change the results:
> 
> 
> $ gfortran-7 -shared -fPIC foo.f90
> ld: illegal text-relocation to '_gee' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o from 'lC0' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o for architecture x86_64
> collect2: error: ld returned 1 exit status
> 

google 'macos ld illegal text-relocation' suggests that this
is a longstanding problem with macos.  Perhaps, a bug report
to Apple is appropriate?

Try adding "-Wl,-read_only_relocs suppress" to your command line.

-- 
Steve

Re: Darwin linker error "illegal text-relocation" with -shared

[Ryan S. Elliott]

On Mon, 16 Apr 2018, Steve Kargl wrote:

> On Mon, Apr 16, 2018 at 02:51:16PM -0500, Ryan S. Elliott wrote:
>>
>> No, you are right.   I should have included the -fPIC flag, but this doesn't
>> change the results:
>>
>>
>> $ gfortran-7 -shared -fPIC foo.f90
>> ld: illegal text-relocation to '_gee' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o from 'lC0' in /var/folders/q0/mth73zrd307d66c43f8r3xv80000gp/T//ccG1nHc0.o for architecture x86_64
>> collect2: error: ld returned 1 exit status
>>
>
> google 'macos ld illegal text-relocation' suggests that this
> is a longstanding problem with macos.  Perhaps, a bug report
> to Apple is appropriate?
>
> Try adding "-Wl,-read_only_relocs suppress" to your command line.

Yes, this is a long standing issue.  I do not believe that it is really an 
apple problem.  I think gfortran is doing something that apple considers 
invalid.

The "-Wl,-read_only_relocs suppress" argument only works if you compile in 32 
bit  (with "-m32") otherwise it is not a valid argument:

$ gfortran-7 -shared -fPIC "-Wl,-read_only_relocs suppress" foo.f90
ld: unknown option: -read_only_relocs suppress
collect2: error: ld returned 1 exit status


Ryan