Re: [PATCH] Fix default_binds_local_p_2 for extern protected data

[Szabolcs Nagy <szabolcs.nagy@arm.com>]

ping.

On 22/07/15 18:01, Szabolcs Nagy wrote:
> The commit
> https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=222184
> changed a true to false in varasm.c:
>
>   bool
>   default_binds_local_p_2 (const_tree exp)
>   {
> -  return default_binds_local_p_3 (exp, flag_shlib != 0, true, true);
> +  return default_binds_local_p_3 (exp, flag_shlib != 0, true, false,
> +				  !flag_pic);
>   }
>
> where
>
>   default_binds_local_p_3 (const_tree exp, bool shlib, bool weak_dominate,
> -			 bool extern_protected_data)
> +			 bool extern_protected_data, bool common_local_p)
>   {
>
> false means that extern protected data binds locally,
> which is wrong if the target can have copy relocations
> against it (then the address must be loaded from GOT
> otherwise the main executable will see different address).
>
> Currently S/390, ARM and AArch64 targets use this predicate
> and the current default is wrong for all of them (they can
> have copy relocs) so I changed the default instead of doing
> it in a target specific way.
>
> The equivalent x86_64 bug was
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
> the default was changed for
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65780
> now i opened
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66912
> for arm and aarch64.
>
> Needs a further binutils patch too to emit R_*_GLOB_DAT
> instead of R_*_RELATIVE relocs for protected data.
> The glibc elf/tst-protected1a and elf/tst-protected1b
> tests depend on this.
>
> Tested ARM and AArch64 targets.
>
> gcc/ChangeLog:
>
> 2015-07-22  Szabolcs Nagy  <szabolcs.nagy@arm.com>
>
> 	PR target/66912
> 	* varasm.c (default_binds_local_p_2): Turn on extern_protected_data.
>
> gcc/testsuite/ChangeLog:
>
> 2015-07-22  Szabolcs Nagy  <szabolcs.nagy@arm.com>
>
> 	PR target/66912
> 	* gcc.target/aarch64/pr66912.c: New.
> 	* gcc.target/arm/pr66912.c: New.
>