Re: [Fortran, (RFC) patch] PR49110/51055 Assignment to alloc. deferred-length character vars

[Tobias Burnus <burnus at net-b dot de>]

Jakub Jelinek wrote:
> On Tue, Dec 18, 2012 at 04:40:10PM +0100, Tobias Burnus wrote:
> > Looks mostly okay, however, I fear that for
> >
> > subroutine foo()
> > character(len=:), allocatable :: str
> > allocate(str, stat=istat)
> > end subroutine foo
> >
> > compiled with "-fno-automatic", gfortran will still generate the
> > non-GFC_PREFIX-mangled string.
> That doesn't compile:
> Error: Allocate-object at (1) with a deferred type parameter requires either a type-spec or SOURCE tag or a MOLD tag

Sorry for the bad example. I added the allocate just to mark the 
variable as used (otherwise no decl is generated); but my cut-down 
example was wrong. Try:

subroutine foo()
  character(len=:), allocatable :: str
  print *, allocated(str)
end subroutine foo


Or one of the examples from PR55733. The example above gives currently 
(w/o your patch):

  static character(kind=1)[1:.str] * str = 0B;
  integer(kind=4) .str;


> Where would be TREE_STATIC set on the length variable with -fno-automatic,
> and on which testcase?

As written, TREE_STATIC is currently not set (which is a bug, cf. 
PR55733); I think one needs a patch like:

--- a/gcc/fortran/trans-decl.c
+++ b/gcc/fortran/trans-decl.c
@@ -1107,3 +1107,4 @@ gfc_create_string_length (gfc_symbol * sym)

-      if (sym->attr.save || sym->ns->proc_name->attr.flavor == FL_MODULE)
+      if (sym->attr.save || sym->ns->proc_name->attr.flavor == FL_MODULE
+         || gfc_option.flag_max_stack_var_size == 0)
        TREE_STATIC (length) = 1;


Tobias