public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
@ 2012-07-13 14:20 ai.azuma at gmail dot com
2012-07-16 9:50 ` [Bug c++/53954] " rguenth at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: ai.azuma at gmail dot com @ 2012-07-13 14:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
Bug #: 53954
Summary: [C++11] Undefined reference to non-odr-used static
const member variable of variadic class template in
DSO with -flto and -Wl,--export-dynamic
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: ai.azuma@gmail.com
Created attachment 27785
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27785
Command-line log
The following code shows the problem with GCC 4.7.2 20120707 on
x86_64-unknown-linux-gnu.
//////////////////////////////////
// foo.cpp
template<typename...>
struct S
{
static const bool value = false;
};
void f() {
typedef decltype(S<>::value) B;
}
//////////////////////////////////
Obviously, `S<>::value' is not odr-used. Therefore, the program should not
require its definition. However, when a DSO is created from the above code with
GCC 4.7.2 20120707, `-flto' and `-Wl,--export-dynamic' options, it requires the
definition of `S<>::value'.
For example, the following command lines result in a link error.
$ g++ -std=c++11 -fPIC -flto -Wl,--export-dynamic -o libfoo.so -shared foo.cpp
$ g++ -std=c++11 -fPIC main.cpp -L. -lfoo
./libfoo.so: undefined reference to `S<>::value'
./libfoo.so: undefined reference to `S<>::value'
collect2: error: ld returned 1 exit status
where main.cpp is a trivial C++ source file like "int main(){}".
Note that neither GCC 4.6.4 20120706 nor 4.8.0 20120708 reproduces the problem.
Note also that the above reproducer originally comes from a likely C++ code
using `std::vector' and `-std=c++11' option, like the following;
/////////////////////
#include <vector>
void f()
{
std::vector<int> v;
v.push_back(0);
}
/////////////////////
When a DSO is created from this code with `-std=c++11', `-lfto' and
`-Wl,--export-dynamic' options, it requires the definition of
`std::allocator_traits<std::allocator<int> >::__construct_helper<int,
int>::value'.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/53954] [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
@ 2012-07-16 9:50 ` rguenth at gcc dot gnu.org
2012-07-16 9:54 ` redi at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-07-16 9:50 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |hubicka at gcc dot gnu.org
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-16 09:49:59 UTC ---
Not sure what happens here, but I believe not odr-using value does not make
the definition not necessary.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/53954] [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
2012-07-16 9:50 ` [Bug c++/53954] " rguenth at gcc dot gnu.org
@ 2012-07-16 9:54 ` redi at gcc dot gnu.org
2012-07-16 9:59 ` redi at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-16 9:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-16 09:54:18 UTC ---
(In reply to comment #0)
> When a DSO is created from this code with `-std=c++11', `-lfto' and
> `-Wl,--export-dynamic' options, it requires the definition of
> `std::allocator_traits<std::allocator<int> >::__construct_helper<int,
> int>::value'.
Ah, that's actually a bug in my libstdc++ code, the definition should be
present.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/53954] [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
2012-07-16 9:50 ` [Bug c++/53954] " rguenth at gcc dot gnu.org
2012-07-16 9:54 ` redi at gcc dot gnu.org
@ 2012-07-16 9:59 ` redi at gcc dot gnu.org
2012-07-16 20:55 ` redi at gcc dot gnu.org
2012-07-19 3:12 ` ai.azuma at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-16 9:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-16 09:58:57 UTC ---
I've created PR 53978 for the libstdc++ fixes
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/53954] [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
` (2 preceding siblings ...)
2012-07-16 9:59 ` redi at gcc dot gnu.org
@ 2012-07-16 20:55 ` redi at gcc dot gnu.org
2012-07-19 3:12 ` ai.azuma at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-16 20:55 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-16 20:55:02 UTC ---
(In reply to comment #0)
> Note also that the above reproducer originally comes from a likely C++ code
> using `std::vector' and `-std=c++11' option, like the following;
>
> /////////////////////
> #include <vector>
>
> void f()
> {
> std::vector<int> v;
> v.push_back(0);
> }
> /////////////////////
>
> When a DSO is created from this code with `-std=c++11', `-lfto' and
> `-Wl,--export-dynamic' options, it requires the definition of
> `std::allocator_traits<std::allocator<int> >::__construct_helper<int,
> int>::value'.
I have no view on whether this PR is valid or not, but the std::vector failure
is fixed for 4.7.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/53954] [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
` (3 preceding siblings ...)
2012-07-16 20:55 ` redi at gcc dot gnu.org
@ 2012-07-19 3:12 ` ai.azuma at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: ai.azuma at gmail dot com @ 2012-07-19 3:12 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53954
Ai Azuma <ai.azuma at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #5 from Ai Azuma <ai.azuma at gmail dot com> 2012-07-19 03:12:21 UTC ---
Hmm, now I have arrived at the conclusion that non-odr-used variables might
require the definition, depending on compiler options etc., and this PR is
invalid, since there is no guarantee in the specification that
non-odr-used-ness of variables makes the definition unnecessary.
I'm sorry. I created this PR based on the wrong assumption. I should have
created a PR reporting the bug in libstdc++. And thank you for the quick fixes.
Again, thank you for your time.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-07-19 3:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-07-13 14:20 [Bug c++/53954] New: [C++11] Undefined reference to non-odr-used static const member variable of variadic class template in DSO with -flto and -Wl,--export-dynamic ai.azuma at gmail dot com
2012-07-16 9:50 ` [Bug c++/53954] " rguenth at gcc dot gnu.org
2012-07-16 9:54 ` redi at gcc dot gnu.org
2012-07-16 9:59 ` redi at gcc dot gnu.org
2012-07-16 20:55 ` redi at gcc dot gnu.org
2012-07-19 3:12 ` ai.azuma at gmail dot com
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).