Fwd: [Patch, fortran, RFC] PR 40958 Reduce size of module files

[Salvatore Filippone]

One more comment is in order: I have tested (and found bugs) in many
compilers: Cray, IBM, Intel etc.
NAG is way ahead of ALL of them  in module file handling. The same
kind of bloat we have here is present in practically all the other
compilers, albeit on a smaller scale due to them typically using a
binary file format; but the NAG .mod files are plain text!

The origin of the bloat (as discussed some time ago) is that each
module file physically includes the USEd modules.
On the one hand, this enables distributing only the last .mod file in
a USE chain, on the other hand complicated USE chains produce bloat
The NAG format apparently never copies the contents of a USEd module,
which leads to saving space, at the price of having to have access ALL
of the .mod files, and not just the final one, when compiling code
downstream.

Salvatore

On Sat, Nov 26, 2011 at 8:29 AM, Salvatore Filippone
<filippone.salvatore@gmail.com> wrote:
>
> On the laptop from which I am writing this I have a NAG license: the
> build takes about 4 mins, and the total module size produced is about
> 1.2 MB
> (yes, that's a little more than ONE MB instead of 400+)
>
> So, I am afraid that the module handling code needs a radical rewrite:
> going down the zlib path requires getting rid of the seeks (something
> that would be useful even in the plain text format!). I am not at all
> sure whether this is any easier than redesigning the module format
> from the ground up.
>
> Salvatore
> p.s.: if anyone wants to pursue this further contact me offlist  and
> I'll send you  the code.
>