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* [Bug c++/106633] New: Hidden visibility on forward declarations impacts visibility of default-visibility class methods
@ 2022-08-15 23:44 mh+gcc at glandium dot org
2022-08-15 23:50 ` [Bug c++/106633] " pinskia at gcc dot gnu.org
2022-08-16 1:05 ` mh+gcc at glandium dot org
0 siblings, 2 replies; 3+ messages in thread
From: mh+gcc at glandium dot org @ 2022-08-15 23:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106633
Bug ID: 106633
Summary: Hidden visibility on forward declarations impacts
visibility of default-visibility class methods
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: mh+gcc at glandium dot org
Target Milestone: ---
This was not happening before GCC 12.
Reduced testcase from a Firefox build failure we got in Debian on armhf:
```
#pragma GCC visibility push(hidden)
namespace std { class type_info; }
#pragma GCC visibility pop
#include <typeinfo>
bool foo(std::type_info& a, std::type_info& b) { return a == b; }
```
Compile with `-O2 -D__GXX_TYPEINFO_EQUALITY_INLINE=0` (the define makes the
problem appear on all platforms, rather than armhf only)
What happens in this example is that the symbol reference to
`std::type_info::operator==` ends up with hidden visibility, instead of default
visibility. With GCC 11 and older versions, it would end up with default
visibility.
On godbolt:
https://godbolt.org/z/hYKjWGaeq
(Ironically(?), that forward declaration comes from ICU working around an old
bug in libstdc++ headers)
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/106633] Hidden visibility on forward declarations impacts visibility of default-visibility class methods
2022-08-15 23:44 [Bug c++/106633] New: Hidden visibility on forward declarations impacts visibility of default-visibility class methods mh+gcc at glandium dot org
@ 2022-08-15 23:50 ` pinskia at gcc dot gnu.org
2022-08-16 1:05 ` mh+gcc at glandium dot org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-08-15 23:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106633
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I don't think this is a gcc bug but rather gcc 12 fixed a bug
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/106633] Hidden visibility on forward declarations impacts visibility of default-visibility class methods
2022-08-15 23:44 [Bug c++/106633] New: Hidden visibility on forward declarations impacts visibility of default-visibility class methods mh+gcc at glandium dot org
2022-08-15 23:50 ` [Bug c++/106633] " pinskia at gcc dot gnu.org
@ 2022-08-16 1:05 ` mh+gcc at glandium dot org
1 sibling, 0 replies; 3+ messages in thread
From: mh+gcc at glandium dot org @ 2022-08-16 1:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106633
Mike Hommey <mh+gcc at glandium dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Mike Hommey <mh+gcc at glandium dot org> ---
Started with
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=a53781c8fd258608780821168a7f5faf7be63690;hp=ba9b07d0259b38a9eccd4eb0df327d3aaabad3c6
... which points to the fact that this is now consistent with the behavior of
forward declarations of any other class...
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-08-15 23:44 [Bug c++/106633] New: Hidden visibility on forward declarations impacts visibility of default-visibility class methods mh+gcc at glandium dot org
2022-08-15 23:50 ` [Bug c++/106633] " pinskia at gcc dot gnu.org
2022-08-16 1:05 ` mh+gcc at glandium dot org
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