From: Janne Blomqvist <blomqvist.janne@gmail.com>
To: "Thomas König" <tk@tkoenig.net>
Cc: Thomas Koenig <tkoenig@netcologne.de>,
Tobias Burnus <tobias@codesourcery.com>,
"fortran@gcc.gnu.org" <fortran@gcc.gnu.org>,
gcc-patches <gcc-patches@gcc.gnu.org>
Subject: Re: [patch, fortran] Load scalar intent-in variables at the beginning of procedures
Date: Wed, 20 Nov 2019 22:32:00 -0000 [thread overview]
Message-ID: <CAO9iq9GuMc+h8W3FzFDLmnPjQMpTY=0G82ivWksykVfiQ4s5DQ@mail.gmail.com> (raw)
In-Reply-To: <CAO9iq9F6-F0nkuFRC+edsA7rN3OTKX20L2k87cwQARy1QHipjA@mail.gmail.com>
On Thu, Nov 21, 2019 at 12:18 AM Janne Blomqvist
<blomqvist.janne@gmail.com> wrote:
>
> On Wed, Nov 20, 2019 at 11:35 PM Thomas König <tk@tkoenig.net> wrote:
> > (Why do we zero %eax
> > before each call? It should not be a variadic call right?)
>
> Not sure. Maybe some belt and suspenders thing? I guess someone better
> versed in ABI minutiae knows better. It's not Fortran-specific though,
> the C frontend does the same when calling a void function.
Ah, scratch that, it is some varargs-thing, I had forgot that a C
function with no arguments or lacking a prototype is considered a
varargs. The code
void foo();
void bar(void);
void testfoo()
{
foo();
}
void testbar()
{
bar();
}
void testunprototyped()
{
baz();
}
generates code (elided scaffolding):
testfoo:
xorl %eax, %eax
jmp foo
testbar:
jmp bar
testunprototyped:
xorl %eax, %eax
jmp baz
So probably this is due to the Fortran procedures lacking an interface
being considered varargs by the caller. Starts to smell like some
leftover from PR 87689?
--
Janne Blomqvist
next prev parent reply other threads:[~2019-11-20 22:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-11 21:57 Thomas König
2019-11-11 22:08 ` Thomas Koenig
2019-11-11 22:53 ` Janne Blomqvist
2019-11-11 23:02 ` Thomas König
2019-11-12 7:48 ` Janne Blomqvist
2019-11-12 12:50 ` Thomas König
2019-11-12 14:33 ` Tobias Burnus
2019-11-12 17:22 ` Thomas König
2019-11-15 7:41 ` Tobias Burnus
2019-11-15 18:07 ` Thomas König
2019-11-16 20:42 ` Thomas Koenig
2019-11-19 10:46 ` Bernhard Reutner-Fischer
2019-11-19 23:04 ` Thomas Koenig
2019-11-20 18:00 ` Bernhard Reutner-Fischer
2019-11-20 20:45 ` Janne Blomqvist
2019-11-20 21:07 ` Steve Kargl
2019-11-20 21:35 ` Bernhard Reutner-Fischer
2019-11-20 20:46 ` Janne Blomqvist
2019-11-20 21:39 ` Thomas König
2019-11-20 22:19 ` Janne Blomqvist
2019-11-20 22:32 ` Janne Blomqvist [this message]
2019-11-21 9:35 ` Janne Blomqvist
2019-11-20 22:37 ` Tobias Burnus
2019-11-20 22:41 ` Thomas König
2019-11-20 22:30 ` Tobias Burnus
2019-11-21 9:41 ` Tobias Burnus
2019-11-21 12:30 ` Richard Biener
2019-11-21 13:17 ` Tobias Burnus
2019-11-21 13:37 ` Tobias Burnus
2019-11-21 14:10 ` Richard Biener
2019-11-21 14:39 ` Tobias Burnus
2019-11-22 10:44 ` Tobias Burnus
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