Hi All,
Thank you for taking care of that, Jakub. I have been overwhelmed by
daytime work since my last posting and, in addition, have yet to set
up a git workflow. This situation is likely to continue for at least
another 3-4 months. I will release all the PRs assigned to me, except
those associated with PDTs for which I do not think there will be any
other takers.
With regard to the other fn spec attributes: I think that we can
assume that they are OK, or at least acceptable, since I did not find
any similar PRs that might implicate a similar problem.
Cheers
Paul
On Thu, 30 Jan 2020 at 07:37, Richard Biener <rguent...@suse.de> wrote:
>
> On Thu, 30 Jan 2020, Jakub Jelinek wrote:
>
> > Hi!
> >
> > This is something that has been discussed already a few months ago, but
> > seems to have stalled. Here is Paul's patch from the PR except for the
> > TREE_STATIC hunk which is wrong, and does the most conservative fn spec
> > tweak for the problematic two builtins we are aware of (to repeat what is in
> > the PR, both .wR and .ww are wrong for these builtins that transform one
> > layout of an descriptor to another one; while the first pointer is properly
> > marked that we only store to what it points to, from the second pointer
> > we copy and reshuffle the content and store into the first one; if there
> > wouldn't be any pointers, ".wr" would be just fine, but as there is a
> > pointer and that pointer is copied to the area pointed by first argument,
> > the pointer effectively leaks that way, so we e.g. can't optimize stores
> > into what the data pointer in the descriptor points to). I haven't
> > analyzed other fn spec attributes in the FE, but think it is better to
> > fix at least this one we have analyzed.
> >
> > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> OK.
>
> Thanks,
> Richard.
>
> > 2020-01-30 Paul Thomas <pa...@gcc.gnu.org>
> > Jakub Jelinek <ja...@redhat.com>
> >
> > PR fortran/92123
> > * trans-decl.c (gfc_get_symbol_decl): Call gfc_defer_symbol_init for
> > CFI descs.
> > (gfc_build_builtin_function_decls): Use ".w." instead of ".ww" or
> > ".wR"
> > for gfor_fndecl_{cfi_to_gfc,gfc_to_cfi}.
> > (convert_CFI_desc): Handle references to CFI descriptors.
> >
> > --- gcc/fortran/trans-decl.c.jj 2020-01-12 11:54:36.600410587 +0100
> > +++ gcc/fortran/trans-decl.c 2020-01-29 10:54:36.771077452 +0100
> > @@ -1552,6 +1552,9 @@ gfc_get_symbol_decl (gfc_symbol * sym)
> > sym->ts.u.cl->backend_decl = build_fold_indirect_ref
> > (sym->ts.u.cl->backend_decl);
> > }
> >
> > + if (is_CFI_desc (sym, NULL))
> > + gfc_defer_symbol_init (sym);
> > +
> > fun_or_res = byref && (sym->attr.result
> > || (sym->attr.function && sym->ts.deferred));
> > if ((sym->attr.dummy && ! sym->attr.function) || fun_or_res)
> > @@ -3763,12 +3766,17 @@ gfc_build_builtin_function_decls (void)
> > get_identifier (PREFIX("internal_unpack")), ".wR",
> > void_type_node, 2, pvoid_type_node, pvoid_type_node);
> >
> > + /* These two builtins write into what the first argument points to and
> > + read from what the second argument points to, but we can't use R
> > + for that, because the directly pointed structure contains a pointer
> > + which is copied into the descriptor pointed by the first argument,
> > + effectively escaping that way. See PR92123. */
> > gfor_fndecl_cfi_to_gfc = gfc_build_library_function_decl_with_spec (
> > - get_identifier (PREFIX("cfi_desc_to_gfc_desc")), ".ww",
> > + get_identifier (PREFIX("cfi_desc_to_gfc_desc")), ".w.",
> > void_type_node, 2, pvoid_type_node, ppvoid_type_node);
> >
> > gfor_fndecl_gfc_to_cfi = gfc_build_library_function_decl_with_spec (
> > - get_identifier (PREFIX("gfc_desc_to_cfi_desc")), ".wR",
> > + get_identifier (PREFIX("gfc_desc_to_cfi_desc")), ".w.",
> > void_type_node, 2, ppvoid_type_node, pvoid_type_node);
> >
> > gfor_fndecl_associated = gfc_build_library_function_decl_with_spec (
> > @@ -4398,6 +4406,8 @@ convert_CFI_desc (gfc_wrapped_block * bl
> > while CFI_desc is the descriptor itself. */
> > if (DECL_LANG_SPECIFIC (sym->backend_decl))
> > CFI_desc = GFC_DECL_SAVED_DESCRIPTOR (sym->backend_decl);
> > + else if (GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (TREE_TYPE
> > (sym->backend_decl))))
> > + CFI_desc = sym->backend_decl;
> > else
> > CFI_desc = NULL;
> >
> >
> > Jakub
> >
> >
>
> --
> Richard Biener <rguent...@suse.de>
> SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
> Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
--
"If you can't explain it simply, you don't understand it well enough"
- Albert Einstein
