Fortran: improve checks of NULL without MOLD as actual argument [PR104819]
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Commit Message
Dear all,
here's a first patch addressing issues with NULL as actual argument:
if the dummy is assumed-rank or assumed length, MOLD shall be present.
There is also an interp on interoperability of c_sizeof and NULL
pointers, for which we have a partially incorrect testcase
(gfortran.dg/pr101329.f90) which gets fixed.
See https://j3-fortran.org/doc/year/22/22-101r1.txt for more.
Furthermore, nested NULL()s are now handled.
Regtested on x86_64-pc-linux-gnu. OK for mainline?
I consider this part as safe and would like to backport to 13-branch.
Objections?
Thanks,
Harald
Comments
On 2/29/24 12:56 PM, Harald Anlauf wrote:
> Dear all,
>
> here's a first patch addressing issues with NULL as actual argument:
> if the dummy is assumed-rank or assumed length, MOLD shall be present.
>
> There is also an interp on interoperability of c_sizeof and NULL
> pointers, for which we have a partially incorrect testcase
> (gfortran.dg/pr101329.f90) which gets fixed.
>
> See https://j3-fortran.org/doc/year/22/22-101r1.txt for more.
>
> Furthermore, nested NULL()s are now handled.
>
> Regtested on x86_64-pc-linux-gnu. OK for mainline?
>
> I consider this part as safe and would like to backport to 13-branch.
> Objections?
>
> Thanks,
> Harald
>
Looks good to me. I think backport is OK as well.
Jerry -
From ce7199b16872b3014be68744329a8f19ddd64b05 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Thu, 29 Feb 2024 21:43:53 +0100
Subject: [PATCH] Fortran: improve checks of NULL without MOLD as actual
argument [PR104819]
gcc/fortran/ChangeLog:
PR fortran/104819
* check.cc (gfc_check_null): Handle nested NULL()s.
(is_c_interoperable): Check for MOLD argument of NULL() as part of
the interoperability check.
* interface.cc (gfc_compare_actual_formal): Extend checks for NULL()
actual arguments for presence of MOLD argument when required by
Interp J3/22-146.
gcc/testsuite/ChangeLog:
PR fortran/104819
* gfortran.dg/pr101329.f90: Adjust testcase to conform to interp.
* gfortran.dg/null_actual_4.f90: New test.
---
gcc/fortran/check.cc | 5 ++-
gcc/fortran/interface.cc | 30 ++++++++++++++++++
gcc/testsuite/gfortran.dg/null_actual_4.f90 | 35 +++++++++++++++++++++
gcc/testsuite/gfortran.dg/pr101329.f90 | 4 +--
4 files changed, 71 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/null_actual_4.f90
@@ -4384,6 +4384,9 @@ gfc_check_null (gfc_expr *mold)
if (mold == NULL)
return true;
+ if (mold->expr_type == EXPR_NULL)
+ return true;
+
if (!variable_check (mold, 0, true))
return false;
@@ -5216,7 +5219,7 @@ is_c_interoperable (gfc_expr *expr, const char **msg, bool c_loc, bool c_f_ptr)
{
*msg = NULL;
- if (expr->expr_type == EXPR_NULL)
+ if (expr->expr_type == EXPR_NULL && expr->ts.type == BT_UNKNOWN)
{
*msg = "NULL() is not interoperable";
return false;
@@ -3296,6 +3296,36 @@ gfc_compare_actual_formal (gfc_actual_arglist **ap, gfc_formal_arglist *formal,
&& a->expr->ts.type != BT_ASSUMED)
gfc_find_vtab (&a->expr->ts);
+ /* Interp J3/22-146:
+ "If the context of the reference to NULL is an <actual argument>
+ corresponding to an <assumed-rank> dummy argument, MOLD shall be
+ present." */
+ if (a->expr->expr_type == EXPR_NULL
+ && a->expr->ts.type == BT_UNKNOWN
+ && f->sym->as
+ && f->sym->as->type == AS_ASSUMED_RANK)
+ {
+ gfc_error ("Intrinsic %<NULL()%> without %<MOLD%> argument at %L "
+ "passed to assumed-rank dummy %qs",
+ &a->expr->where, f->sym->name);
+ ok = false;
+ goto match;
+ }
+
+ if (a->expr->expr_type == EXPR_NULL
+ && a->expr->ts.type == BT_UNKNOWN
+ && f->sym->ts.type == BT_CHARACTER
+ && !f->sym->ts.deferred
+ && f->sym->ts.u.cl
+ && f->sym->ts.u.cl->length == NULL)
+ {
+ gfc_error ("Intrinsic %<NULL()%> without %<MOLD%> argument at %L "
+ "passed to assumed-length dummy %qs",
+ &a->expr->where, f->sym->name);
+ ok = false;
+ goto match;
+ }
+
if (a->expr->expr_type == EXPR_NULL
&& ((f->sym->ts.type != BT_CLASS && !f->sym->attr.pointer
&& (f->sym->attr.allocatable || !f->sym->attr.optional
new file mode 100644
@@ -0,0 +1,35 @@
+! { dg-do compile }
+! PR fortran/104819
+!
+! Reject NULL without MOLD as actual to an assumed-rank dummy.
+! See also interpretation request at
+! https://j3-fortran.org/doc/year/22/22-101r1.txt
+!
+! Test nested NULL()
+
+program p
+ implicit none
+ integer, pointer :: a, a3(:,:,:)
+ character(10), pointer :: c
+
+ call foo (a)
+ call foo (a3)
+ call foo (null (a))
+ call foo (null (a3))
+ call foo (null (null (a))) ! Valid: nested NULL()s
+ call foo (null (null (a3))) ! Valid: nested NULL()s
+ call foo (null ()) ! { dg-error "passed to assumed-rank dummy" }
+
+ call str (null (c))
+ call str (null (null (c)))
+ call str (null ()) ! { dg-error "passed to assumed-length dummy" }
+contains
+ subroutine foo (x)
+ integer, pointer, intent(in) :: x(..)
+ print *, rank (x)
+ end
+
+ subroutine str (x)
+ character(len=*), pointer, intent(in) :: x
+ end
+end
@@ -8,6 +8,6 @@ program p
integer(c_int64_t), pointer :: ip8
print *, c_sizeof (c_null_ptr) ! valid
print *, c_sizeof (null ()) ! { dg-error "is not interoperable" }
- print *, c_sizeof (null (ip4)) ! { dg-error "is not interoperable" }
- print *, c_sizeof (null (ip8)) ! { dg-error "is not interoperable" }
+ print *, c_sizeof (null (ip4)) ! valid
+ print *, c_sizeof (null (ip8)) ! valid
end
--
2.35.3