[PATCH] Enable deterministic archives

Ralf Corsepius ralf.corsepius at rtems.org
Tue Feb 5 16:40:02 UTC 2013


On 02/05/2013 09:00 AM, Sebastian Huber wrote:
> The GNU AR program as a 'D' option
> (http://sourceware.org/binutils/docs/binutils/ar-cmdline.html#ar-cmdline):
>
> [...]
> `D'
>      Operate in deterministic mode. When adding files and the archive
> index use zero for UIDs, GIDs, timestamps, and use consistent file modes
> for all files. When this option is used, if ar is used with identical
> options and identical input files, multiple runs will create identical
> output files regardless of the input files' owners, groups, file modes,
> or modification times.
>
>      If binutils was configured with --enable-deterministic-archives,
> then this mode is on by default. It can be disabled with the `U'
> modifier, below.
> [...]
>
> This helps to avoid artificial differences in archives and thus makes it
> easier to use version control for archives (e.g. static libraries).

This introduces a gnu-binutils proprietary/non-portable feature into 
gnu-binutils. It definitely adds artifical contraints to gnu-ar and 
activates a bleeding-edge feature, whose downsides are not yet known.

That said, I feel this change is overzealous and based on the very 
specific demands of a very small circle. Making RTEMS relying upon it at 
the moment seems premature to me.

Apart of this, this patch is incomplete, because it also activates this 
stuff for non-rtems targets.

I am not going to apply this patch - May-be re-visited with 
binutils-2.25 or so.

Ralf





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