From: Iain Sandoe <iain@sandoe.co.uk>
To: gcc@gcc.gnu.org
Cc: Nathan Sidwell <nathan@acm.org>, Jason Merrill <jason@redhat.com>
Subject: Function signatures in extern "C".
Date: Sun, 6 Sep 2020 16:22:06 +0100 [thread overview]
Message-ID: <3EED366A-21C9-47E9-89B0-BBDAF0AE740D@sandoe.co.uk> (raw)
Hi
g++.dg/abi/guard3.C
has:
extern "C" int __cxa_guard_acquire();
Which might not be a suitable declaration, depending on how the ‘extern
“C”’ is supposed to affect the function signature generated.
IF, the extern C should make this parse as a “K&R” style function - then
the TYPE_ARG_TYPES should be NULL (and the testcase is OK).
However, we are parsing the decl as int __cxa_guard_acquire(void) (i.e. C++
rules on the empty parens), which makes the testcase not OK.
This means that the declaration is now misleading (and it’s just luck that
expand_call happens to count the length of the TYPE_ARG_TYPES list without
looking to see what the types are) - in this case it happens to work out
from this luck - since there’s only one arg so the length of the void args
list agrees with what we want.
——
So .. the question is “which is wrong, the test-case or the assignment of
the TYPE_ARG_TYPES”?
[we can’t easily diagnose this at this point, but I do have a patch to
diagnose the case where we pass a void-list to expand_call and then try to
expand a call to the callee with an inappropriate set of parms]
(it’s trivial to fix the test-case as extern "C" int
__cxa_guard_acquire(__UINT64_TYPE__ *);, I guess)
thanks
Iain
next reply other threads:[~2020-09-06 15:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-06 15:22 Iain Sandoe [this message]
2020-09-06 20:23 ` Jonathan Wakely
2020-09-06 20:43 ` Iain Sandoe
2020-09-06 23:05 ` Nathan Sidwell
2020-09-07 8:16 ` Iain Sandoe
2020-09-07 9:27 ` Jonathan Wakely
2020-09-07 9:34 ` Jakub Jelinek
2020-09-07 10:29 ` Jonathan Wakely
2020-09-10 7:58 ` Florian Weimer
2020-09-07 9:38 ` Iain Sandoe
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