On 16.10.21 20:54, Jan Hubicka wrote:
> I wrote:
>> Fortran has for a long time 'character(len=5), allocatable" or
>> "character(len=*)". In the first case, the "5" can be ignored as both
>> caller and callee know the length. In the second case, the length is
>> determined by the argument, but it cannot be changed.
>>
>> Since a not-that-short while, 'len=:' together with allocatable/pointer
>> is supported.
>>
>> In the latter case, the value can be change when the array
>> association/allocation is changed.
>> ...
>> +      if (!sym->ts.u.cl->length
>> +          && ((sym->attr.allocatable && sym->attr.target)
>> +              || sym->attr.pointer))
>> +        spec[spec_len++] = '.';
>> +      if (!sym->ts.u.cl->length && sym->attr.allocatable)
>> +        spec[spec_len++] = 'w';
>> +      else
>> +        spec[spec_len++] = 'R';
> Also escaping is quite important bit of information so it would be
> good to figure out if it really can escape rather than playing safe.

The pointer to the string length variable itself does not escape,
only its integer string value:

subroutine foo(x)
   character(len=:), pointer :: x
   character(len=:), pointer :: y
   y => x
has in the dump:
   .y = *_x;
   y = (character(kind=1)[1:.y] *) *x;

Thus, 'w' can always be used.

Committed as obvious as r12-4511-gff0eec94e87dfb7dc387f120ca5ade2707aecf50

Tobias
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