http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25708
Janne Blomqvist <jb at gcc dot gnu.org> changed:
What |Removed |Added
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AssignedTo|jvdelisle at gcc dot |pault at gcc dot gnu.org
|gnu.org |
--- Comment #15 from Janne Blomqvist <jb at gcc dot gnu.org> 2011-04-05
05:34:57 UTC ---
(In reply to comment #12)
> (In reply to comment #11)
> > An associated issue is the size of module files.
>
> Joost suggested to cut down the string tags "d" instead of "dimension", "al"
> instead of "allocatable" or something like that. That would help with the file
> size, the I/O (also: I/O caching), and the string parsing.
FWIW, this is http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40958
Another option would be to compress the mod file with zlib; there is a copy in
the gcc tree already.
There also seems to be a bit of redundancy in the module files, e.g. things
like null atoms "()" which I guess can be removed? I'm not sure how big an
effect this would have, though.
> > Clearly, where a module uses
> > another module, we could help by inserting use statements in the module
> > file.
>
> There are pro and cons doing so. For binary-only code, it is much more
> convenient to ship only a single ".mod" instead of several - that was at least
> a complaint I have heard about NAG's compiler. Though, having by default a
> simple "use" in the .mod file would help.
To reiterate my comments from
http://gcc.gnu.org/ml/fortran/2010-09/msg00512.html
the go developers claim that including the transitive dependencies is a major
reason why go compilation is fast. See pages 9-10 on
http://assets.en.oreilly.com/1/event/45/Another%20Go%20at%20Language%20Design%20Presentation.pdf
In the Fortran case, additionally by doing it this way one can take care of
ONLY and renamed symbols when generating the .mod file.
> Another thing which could help is to read a .mod file only once per
> translation
> unit (source file) instead of every time a USE statement is encountered.
I think this is the major issue, yes.
