[Bug fortran/95998] gfc_typename use of static memory

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95998

--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
(In reply to Dominique d'Humieres from comment #1)
> Is static in C/C++ equivalent of SAVE in fortran (at least in the context of
> gfc_typename)?

Yes.

> If yes, AFAIU the code the odd access to gfc_typename use buffer2, while
> even ones
> use buffer1? Wouldn't it be simple (safer?) to use only buffer1?
> 
>   static char buffer[GFC_MAX_SYMBOL_LEN + 7];  /* 7 for "TYPE()" + '\0'.  */
>   gfc_typespec *ts1;
>   gfc_charlen_t length = 0;
> 
> Same thing for gfc_dummy_typename, gfc_typename, ... .

If we ever have three occurences of gfc_typename in a function list,
like

   foo (gfc_typename(a), gfc_typename(b), gfc_typename(c));

we will get the wrong result for the third one.  We will also get
a wrong result for

   pa = gfc_typename(a);
   pb = gfc_typename(b);
   pc = gfc_typename(c);

because then pa will point to the same memory as pc.