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Re: C++ PATCH for c++/86094, wrong calling convention for move-only class
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 15 Jun 2018 16:08:00 -0400
- Subject: Re: C++ PATCH for c++/86094, wrong calling convention for move-only class
- References: <CADzB+2niH+fNdufwCs6tzbjo1Ums=JJnCyriqB0df6YBX3DdwA@mail.gmail.com> <CADzB+2=A8GSacQnoc8tP-0iQp0-JJM5aneChepF_5CLi92fsOg@mail.gmail.com> <CADzB+2m0pHLFgwtFp_tHH_D5qZzxz6VpRQ2Jao2ZPzq+8jd1jQ@mail.gmail.com>
On Wed, Jun 13, 2018 at 5:05 PM, Jason Merrill <jason@redhat.com> wrote:
> On Wed, Jun 13, 2018 at 4:12 PM, Jason Merrill <jason@redhat.com> wrote:
>> On Mon, Jun 11, 2018 at 2:38 PM, Jason Merrill <jason@redhat.com> wrote:
>>> The fix for 80178 was broken, because I forgot that copy_fn_p is false
>>> for move constructors. As a result, the calling convention for a
>>> class with a trivial move constructor and deleted copy constructor
>>> changed inappropriately.
>>
>> This patch restores the broken behavior to -fabi-version=12 and adds
>> -fabi-version=13 for the fix; people can use -Wabi=12 with GCC 8.2 to
>> check for compatibility issues against 8.1, or -Wabi=11 to check
>> compatibility with GCC 7.
>>
>> Tested x86_64-pc-linux-gnu, applying to trunk and 8. Do we want to
>> accelerate 8.2 because of this issue?
>
> And one more patch, to suggest -Wabi=11 rather than useless plain -Wabi.
...and another improvement to the warning.
Tested x86_64-pc-linux-gnu, applying to trunk and 8.
commit 3825732dc47c121f0c2d08dfa1993d0cf008ce89
Author: Jason Merrill <jason@redhat.com>
Date: Thu Jun 14 14:36:20 2018 -0400
* tree.c (maybe_warn_parm_abi): Inform the location of the class.
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 48a0ff37372..a88481db1e0 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -4074,25 +4074,23 @@ maybe_warn_parm_abi (tree t, location_t loc)
if ((flag_abi_version == 12 || warn_abi_version == 12)
&& classtype_has_non_deleted_move_ctor (t))
{
+ bool w;
if (flag_abi_version > 12)
- warning_at (loc, OPT_Wabi, "-fabi-version=13 (GCC 8.2) fixes the "
- "calling convention for %qT, which was accidentally "
- "changed in 8.1", t);
+ w = warning_at (loc, OPT_Wabi, "-fabi-version=13 (GCC 8.2) fixes the "
+ "calling convention for %qT, which was accidentally "
+ "changed in 8.1", t);
else
- warning_at (loc, OPT_Wabi, "-fabi-version=12 (GCC 8.1) accidentally "
- "changes the calling convention for %qT", t);
+ w = warning_at (loc, OPT_Wabi, "-fabi-version=12 (GCC 8.1) accident"
+ "ally changes the calling convention for %qT", t);
+ if (w)
+ inform (location_of (t), " declared here");
return;
}
- warning_at (loc, OPT_Wabi, "the calling convention for %qT changes in "
- "-fabi-version=13 (GCC 8.2)", t);
- static bool explained = false;
- if (!explained)
- {
- inform (loc, " because all of its copy and move constructors "
- "are deleted");
- explained = true;
- }
+ if (warning_at (loc, OPT_Wabi, "the calling convention for %qT changes in "
+ "-fabi-version=13 (GCC 8.2)", t))
+ inform (location_of (t), " because all of its copy and move "
+ "constructors are deleted");
}
/* Returns true iff copying an object of type T (including via move
diff --git a/gcc/testsuite/g++.dg/abi/invisiref2a.C b/gcc/testsuite/g++.dg/abi/invisiref2a.C
index 05330553287..127ee0ae763 100644
--- a/gcc/testsuite/g++.dg/abi/invisiref2a.C
+++ b/gcc/testsuite/g++.dg/abi/invisiref2a.C
@@ -3,7 +3,7 @@
// { dg-additional-options "-fabi-version=12 -Wabi -fdump-tree-gimple" }
// { dg-final { scan-tree-dump "struct S &" "gimple" } }
-struct S {
+struct S { // { dg-message "" }
S(S&&) = default;
int i;
};