[Bug target/59888] ld: illegal text-relocation to '_compute' ... on darwin1(2|3).

[fxcoudert at gcc dot gnu.org]

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

--- Comment #6 from Francois-Xavier Coudert fxcoudert at gcc dot gnu.org ---
(In reply to Iain Sandoe from comment #4)
 Whether this is a back-end fault or perhaps a constraint of darwin not
 present for binutils-ld I cannot tell immediately and would welcome input
 from the Fortran maintainers as to the decoration intended for the indirect
 reference produced for c_funloc (defined_function).

Iain, I am willing to help there but do not understand exactly what you are
asking for. Below is a short explanation of what the Fortran front-end is
trying to do.

Let's take this code, which compiles fine on darwin:

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

Here GEE takes as single argument a function pointer, and has no return type.
The code in BAR is equivalent to calling gee, with its own address as argument.


Now, the second case passes the GEE argument by reference:

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

This generates the linker error:

ld: illegal text-relocation to '___foo_MOD_gee' in a.o from 'anon' in a.o for
architecture x86_64

If you look at the tree dump (-fdump-tree-original), you can see that instead
of being just:

bar () { gee(gee); }

in the previous case, it now uses a temporary variable to pass by reference:

bar ()
{
  static void (*T618) (void (*T68) (void)  restrict) C.2324 = gee;
  gee (C.2324);
}



Let me know what else I can do to help solve this.

[Bug target/59888] ld: illegal text-relocation to '_compute' ... on darwin1(2|3).

[fxcoudert at gcc dot gnu.org]

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

Francois-Xavier Coudert fxcoudert at gcc dot gnu.org changed:

   What|Removed |Added

 CC||fxcoudert at gcc dot gnu.org

--- Comment #5 from Francois-Xavier Coudert fxcoudert at gcc dot gnu.org ---
Reduced testcase, still failing with -shared on darwin14:

module foo
contains

  subroutine bar
use, intrinsic :: iso_c_binding
call gee(c_funloc(gee))
  end subroutine

  subroutine gee(f)
use, intrinsic :: iso_c_binding
type(c_funptr) :: f
  end subroutine 

end module foo

[Bug target/59888] ld: illegal text-relocation to '_compute' ... on darwin1(2|3).

[dominiq at lps dot ens.fr]

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

Dominique d'Humieres dominiq at lps dot ens.fr changed:

   What|Removed |Added

Summary|ld: warning: PIE disabled.  |ld: illegal text-relocation
   |Absolute addressing |to '_compute' ... on
   |(perhaps -mdynamic-no-pic)  |darwin1(2|3).
   |not allowed in code signed  |
   |PIE ... |

--- Comment #3 from Dominique d'Humieres dominiq at lps dot ens.fr ---
Changed the summary to reflect the original post.

[Bug target/59888] ld: illegal text-relocation to '_compute' ... on darwin1(2|3).

[iains at gcc dot gnu.org]

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

--- Comment #4 from Iain Sandoe iains at gcc dot gnu.org ---
So, essentially, the complaint from the darwin linker is that it does not want
to see a relocation in the .const section (which is part of the text segment).

It might be argued that this is right/wrong - but it is at least reasonable -
the relevant segment should be marked read-only .. but typical darwin relocs
can be re-written lazily (as and when the symbol is required).

the hack, proof-of-principle, solution above was to move the reference to the
.const_data section.

Whether this is a back-end fault or perhaps a constraint of darwin not present
for binutils-ld I cannot tell immediately and would welcome input from the
Fortran maintainers as to the decoration intended for the indirect reference
produced for c_funloc (defined_function).