[Bug fortran/44945] [4.6 Regression] Wrong decl for module vars / FAIL: gfortran.dg/char_array_structure_constructor.f90

["pault at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #27 from pault at gcc dot gnu dot org  2010-08-17 09:42 -------
(In reply to comment #25)
> (In reply to comment #21)
> > In my opinion revision 162487 is only a partial fix of the problem. If I split
> > a modified test case in two files: [...] I still get [...] Bus error
> 
> (In reply to comment #24)
> > Look at -fdump-tree-original-uid dumps and see if you find the
> > same decl with two different UIDs.  I bet you will.
> 
> One does. The problem is that when the module is not available.
> 
> The variable "c" (of example in comment 21) created for the main program
> "char_array_structure_constructor" but if one searches for the symbol (in
> gfc_get_symbol_decl) via
>           gsym =  gfc_find_gsymbol (gfc_gsym_root, sym->module);
> the result is NULL as the only gsym which exists in gfc_gsym_root is the one
> for "char_array_structure_constructor" as there is none for the module. One
> should create a "fake" gsym for modules, if the module does not exist, and put
> there the variables, functions, and type declarations - such that they can be
> found if needed.
> 

Tobias,

This is a very good suggestion. I will have a think about how to implement it
and will come back to you.  It is consistent with what I had in mind to improve
the efficiency of module reading.  ie. read_module proceeds as follows:

(i) On encountering a USE statement, look for the module gsym.  If it does not
exist, use read_module, as at present, to construct the namespace, without any
exclusions or renames;
(ii) In the current scope, create symtrees using the ONLY and the renames and
point to the symbols in the gsym namespace;
(iii) Subsequent USEs of the same module proceed by using the gsym namespace.

I think that Andy was smoking something or was having a whimsical spell when he
wrote module.c.  Whilst it is very elegant, it is unnecessarily disjunct from
the rest of the frontend and could have been done as above.

Cheers

Paul


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44945