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Re: [Patch] PR fortran/92470 Fixes for CFI_address
I too had some considerable difficulty on this point. I wasn't at all
sure that the C world view was relevant here since the API includes
CFI_address and, in principle, one could reference directly the
elements pointed to by base_addr. However, I bow to the wisdom of your
correspondents on the j3 list :-)
OK for both trunk and 9-branch.
Thanks for the patch.
Paul
On Tue, 12 Nov 2019 at 20:25, Tobias Burnus <tobias@codesourcery.com> wrote:
>
> Hi all,
>
> On 11/12/19 3:42 PM, Tobias Burnus wrote:
> > (2) CFI_establish: For allocatables, it is clear – base_addr == NULL.
> > For pointers, it is clear as well – it has to be '0' according to the
> > standard. But for CFI_attribute_other … I have now asked at
> > https://mailman.j3-fortran.org/pipermail/j3/2019-November/thread.html#11740
> >
>
> While I still have problems to decipher the standard, regarding
> CFI_establish, Steve L wrote:
>
> "In the C descriptor world, arrays start at zero as they do in C. The
> only way they can become non-zero is through argument association,
> allocation or pointer association as specified in 18.5.3p3. For
> non-pointer, not-allocatable objects (this means "other"), the lower
> bounds are supposed to be always zero."
>
> Hence, I now also set it for CFI_attribute_other to 0 – and check it in
> a test case (most users there have NULL as base_addr, hence, only a
> single assert is in that file).
>
> Build on x86-64_gnu-linux.
> OK for the trunk and GCC-9?
>
> Tobias
>
--
"If you can't explain it simply, you don't understand it well enough"
- Albert Einstein