This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: PATCH RFA: Build stages 2 and 3 with C++


Jakub Jelinek <jakub@redhat.com> writes:

> On Thu, Jul 21, 2011 at 08:51:46AM -0700, Ian Lance Taylor wrote:
>> Basile Starynkevitch <basile@starynkevitch.net> writes:
>> 
>> > I have a similar issue in the MELT branch, and I am passing to -frandom-seed the md5sum
>> > of relevant source files. With such a trick, the seed is reproducible from one build to
>> > the next one (of the exact same source tree), and does provide much more randomness than
>> > just using 0 all the time.
>> 
>> In practice I think it is fine to just pass the source file name to
>> -frandom-seed.  That's what the patch I sent out does.  The source file
>> name should be unique within a given program.
>
> Isn't the filename already encoded in what get_file_function_name returns?
> It is <filename>_<weak_var_name_crc32>_<random_seed_crc32>, so IMHO
> -frandom-seed=$@ brings almost no advantages at all over -frandom-seed=0.
> Except perhaps for the characters from the filename that are
> wiped into _ by clean_symbol_name.

That's a fair point, but I guess I still think using the file name with
-frandom-seed is going to be more future-proof against other users of
random numbers.

Ian


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]