[Trunk/GCC 4.6] Re: [google] Omit date from Fortran .mod files for reproducible builds

[Tobias Burnus <burnus at net-b dot de>]

We (Janne and I) think this patch can also be applied to the GCC 4.6 
trunk; as the date is never read there is also no .mod ABI issue.

I assume that there are no copyright issues.

Cf. also short "discussion"
   at http://gcc.gnu.org/ml/fortran/2011-01/msg00270.html

Tobias

On 01/27/2011 03:00 PM, Simon Baldwin wrote:
> Omit date from Fortran .mod files for reproducible builds.
>
> Strict build environments do binary comparisons of files across gcc builds.
> Writing the current timestamp into a Fortran .mod file leads to false
> positives from such environments.  Omitting the timestamp removes these
> false positives.
>
> Targeted for the google/integration branch.
>
> gcc/fortran/ChangeLog.google:
> 2011-01-27  Simon Baldwin<simonb@google.com>
>
> 	* module.c (gfc_dump_module): Omit timestamp from output.
>
> Google ref: 39202, 25691, 13445, 13307
>
>
> Index: gcc/fortran/module.c
> ===================================================================
> --- gcc/fortran/module.c	(revision 169330)
> +++ gcc/fortran/module.c	(working copy)
> @@ -5116,8 +5116,7 @@ void
>   gfc_dump_module (const char *name, int dump_flag)
>   {
>     int n;
> -  char *filename, *filename_tmp, *p;
> -  time_t now;
> +  char *filename, *filename_tmp;
>     fpos_t md5_pos;
>     unsigned char md5_new[16], md5_old[16];
>
> @@ -5159,13 +5158,8 @@ gfc_dump_module (const char *name, int d
>   		     filename_tmp, xstrerror (errno));
>
>     /* Write the header, including space reserved for the MD5 sum.  */
> -  now = time (NULL);
> -  p = ctime (&now);
> -
> -  *strchr (p, '\n') = '\0';
> -
> -  fprintf (module_fp, "GFORTRAN module version '%s' created from %s on %s\n"
> -	   "MD5:", MOD_VERSION, gfc_source_file, p);
> +  fprintf (module_fp, "GFORTRAN module version '%s' created from %s\n"
> +	   "MD5:", MOD_VERSION, gfc_source_file);
>     fgetpos (module_fp,&md5_pos);
>     fputs ("00000000000000000000000000000000 -- "
>   	"If you edit this, you'll get what you deserve.\n\n", module_fp);