* [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877]
@ 2023-03-17 21:36 Harald Anlauf
2023-03-18 18:52 ` Thomas Koenig
0 siblings, 1 reply; 5+ messages in thread
From: Harald Anlauf @ 2023-03-17 21:36 UTC (permalink / raw)
To: fortran, gcc-patches
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Dear all,
the Fortran standard requires an explicit procedure interface in certain
situations, such as when they have a BIND(C) attribute (F2018:15.4.2.2).
The attached patch adds a check for this.
Regtested on x86_64-pc-linux-gnu. OK for mainline?
The PR marks this as a long-time regression, so it might be backported
to all open branches.
Thanks,
Harald
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From c48c670ff0ce4f0d2ffb1d43aca2ec1bed1fa2ef Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Fri, 17 Mar 2023 22:24:49 +0100
Subject: [PATCH] Fortran: procedures with BIND(C) attribute require explicit
interface [PR85877]
gcc/fortran/ChangeLog:
PR fortran/85877
* resolve.cc (resolve_fl_procedure): Check for an explicit interface
of procedures with the BIND(C) attribute (F2018:15.4.2.2).
gcc/testsuite/ChangeLog:
PR fortran/85877
* gfortran.dg/pr85877.f90: New test.
---
gcc/fortran/resolve.cc | 10 ++++++++++
gcc/testsuite/gfortran.dg/pr85877.f90 | 17 +++++++++++++++++
2 files changed, 27 insertions(+)
create mode 100644 gcc/testsuite/gfortran.dg/pr85877.f90
diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc
index 46585879ddc..7ec65f16240 100644
--- a/gcc/fortran/resolve.cc
+++ b/gcc/fortran/resolve.cc
@@ -13661,6 +13661,16 @@ check_formal:
}
}
}
+
+ /* F2018:15.4.2.2 requires an explicit interface for procedures with the
+ BIND(C) attribute. */
+ if (sym->attr.is_bind_c && sym->attr.if_source == IFSRC_UNKNOWN)
+ {
+ gfc_error ("Interface of %qs at %L must be explicit",
+ sym->name, &sym->declared_at);
+ return false;
+ }
+
return true;
}
diff --git a/gcc/testsuite/gfortran.dg/pr85877.f90 b/gcc/testsuite/gfortran.dg/pr85877.f90
new file mode 100644
index 00000000000..675faac0027
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr85877.f90
@@ -0,0 +1,17 @@
+! { dg-do compile }
+! PR fortran/85877
+! A procedure with the bind(c) attribute shall have an explicit interface
+! Contributed by G. Steinmetz
+
+subroutine p
+ bind(c) f ! { dg-error "must be explicit" }
+ x = f()
+end
+
+subroutine s
+ interface
+ function g() bind(c)
+ end function g
+ end interface
+ x = g()
+end
--
2.35.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877]
2023-03-17 21:36 [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877] Harald Anlauf
@ 2023-03-18 18:52 ` Thomas Koenig
2023-03-18 20:59 ` Harald Anlauf
0 siblings, 1 reply; 5+ messages in thread
From: Thomas Koenig @ 2023-03-18 18:52 UTC (permalink / raw)
To: Harald Anlauf, fortran, gcc-patches
Hi Harald,
> the Fortran standard requires an explicit procedure interface in certain
> situations, such as when they have a BIND(C) attribute (F2018:15.4.2.2).
> The attached patch adds a check for this.
>
> Regtested on x86_64-pc-linux-gnu. OK for mainline?
While this fixes the ICE, it misses
function f() bind(c)
f = 42.
end
subroutine p
bind(c) f ! { dg-error "must be explicit" }
x = f()
end
subroutine s
interface
function g() bind(c)
end function g
end interface
x = g()
end
where the interface is picked up via a global symbol. This code
may not be valid; nagfor rejects it, but I cannot find a
constraint at least in the F2022 draft that prohibits it.
Hm... might it be better to check for attr->module_procedure ||
attr->if_source == IFSRC_IFBODY?
Best regards
Thomas
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877]
2023-03-18 18:52 ` Thomas Koenig
@ 2023-03-18 20:59 ` Harald Anlauf
2023-03-19 7:34 ` Thomas Koenig
0 siblings, 1 reply; 5+ messages in thread
From: Harald Anlauf @ 2023-03-18 20:59 UTC (permalink / raw)
To: Thomas Koenig, fortran, gcc-patches
Hi Thomas,
Am 18.03.23 um 19:52 schrieb Thomas Koenig via Gcc-patches:
> Hi Harald,
>
>> the Fortran standard requires an explicit procedure interface in certain
>> situations, such as when they have a BIND(C) attribute (F2018:15.4.2.2).
>> The attached patch adds a check for this.
>>
>> Regtested on x86_64-pc-linux-gnu. OK for mainline?
>
> While this fixes the ICE, it misses
>
> function f() bind(c)
> f = 42.
> end
>
> subroutine p
> bind(c) f ! { dg-error "must be explicit" }
> x = f()
> end
what do you mean by "it misses"? I do not see an explicit interface
here, only a global symbol. All compiler I tried with the above
code reject it one way or the other, e g. Cray:
x = f()
^
ftn-954 crayftn: ERROR P, File = pr85877-2.f90, Line = 12, Column = 3
Procedure "f", referenced at line 6 (pr85877-2.f90) must have an
explicit interface because one or more arguments have the BIND attribute.
> subroutine s
> interface
> function g() bind(c)
> end function g
> end interface
> x = g()
> end
>
> where the interface is picked up via a global symbol.
Is it really true that this is in the spirit of the standard?
Is the global declaration above really equivalent to an explicit
interface?
I would expect legal code to be like:
function g() bind(c)
g = 42.
end
subroutine s
interface
function g() bind(c)
end function g
end interface
x = g()
end
unless you do it in the context of a module and in the right way.
> This code
> may not be valid; nagfor rejects it, but I cannot find a
> constraint at least in the F2022 draft that prohibits it.
I thought that F2018:15.4.2.2 and F2023:15.4.2.2(7) are rather
clear and "explicit" on this. IMHO the case of "f" above seems
to be excluded and thus not conforming.
> Hm... might it be better to check for attr->module_procedure ||
> attr->if_source == IFSRC_IFBODY?
Maybe we should find a set of legal and illegal cases that we
can agree upon.
Thanks,
Harald
> Best regards
>
> Thomas
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877]
2023-03-18 20:59 ` Harald Anlauf
@ 2023-03-19 7:34 ` Thomas Koenig
2023-03-19 19:38 ` Harald Anlauf
0 siblings, 1 reply; 5+ messages in thread
From: Thomas Koenig @ 2023-03-19 7:34 UTC (permalink / raw)
To: Harald Anlauf, fortran, gcc-patches
Hi Harald,
> Am 18.03.23 um 19:52 schrieb Thomas Koenig via Gcc-patches:
>> Hi Harald,
>>
>>> the Fortran standard requires an explicit procedure interface in certain
>>> situations, such as when they have a BIND(C) attribute (F2018:15.4.2.2).
>>> The attached patch adds a check for this.
>>>
>>> Regtested on x86_64-pc-linux-gnu. OK for mainline?
>>
>> While this fixes the ICE, it misses
>>
>> function f() bind(c)
>> f = 42.
>> end
>>
>> subroutine p
>> bind(c) f ! { dg-error "must be explicit" }
>> x = f()
>> end
>
> what do you mean by "it misses"?
Sorry, that was caused by confusion on my part (and it is better
to test an assumption of what the compiler actually does :-)
Patch is OK, also for backport. Maybe you can also include the
test above, just to make sure.
Best regards
Thomas
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877]
2023-03-19 7:34 ` Thomas Koenig
@ 2023-03-19 19:38 ` Harald Anlauf
0 siblings, 0 replies; 5+ messages in thread
From: Harald Anlauf @ 2023-03-19 19:38 UTC (permalink / raw)
To: Thomas Koenig, fortran, gcc-patches
Hi Thomas,
Am 19.03.23 um 08:34 schrieb Thomas Koenig via Gcc-patches:
> Hi Harald,
>
>> Am 18.03.23 um 19:52 schrieb Thomas Koenig via Gcc-patches:
>>> Hi Harald,
>>>
>>>> the Fortran standard requires an explicit procedure interface in
>>>> certain
>>>> situations, such as when they have a BIND(C) attribute
>>>> (F2018:15.4.2.2).
>>>> The attached patch adds a check for this.
>>>>
>>>> Regtested on x86_64-pc-linux-gnu. OK for mainline?
>>>
>>> While this fixes the ICE, it misses
>>>
>>> function f() bind(c)
>>> f = 42.
>>> end
>>>
>>> subroutine p
>>> bind(c) f ! { dg-error "must be explicit" }
>>> x = f()
>>> end
>>
>> what do you mean by "it misses"?
>
> Sorry, that was caused by confusion on my part (and it is better
> to test an assumption of what the compiler actually does :-)
>
> Patch is OK, also for backport. Maybe you can also include the
> test above, just to make sure.
I've added your suggestion to the testcase. Pushed as:
https://gcc.gnu.org/g:5426ab34643d9e6502f3ee572891a03471fa33ed
> Best regards
>
> Thomas
>
>
Thanks,
Harald
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-03-17 21:36 [PATCH] Fortran: procedures with BIND(C) attribute require explicit interface [PR85877] Harald Anlauf
2023-03-18 18:52 ` Thomas Koenig
2023-03-18 20:59 ` Harald Anlauf
2023-03-19 7:34 ` Thomas Koenig
2023-03-19 19:38 ` Harald Anlauf
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