[Bug c++/54276] New: Lambda in a Template Function Undefined Reference to local static

[Bug c++/54276] New: Lambda in a Template Function Undefined Reference to local static

[travis at gockelhut dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

             Bug #: 54276
           Summary: Lambda in a Template Function Undefined Reference to
                    local static
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: travis@gockelhut.com


Created attachment 28021
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28021
Compile

The following code will fail to link with "undefined reference to `x'" when
compiled with g++ (4.6.1, 4.6.2, 4.6.3 and 4.7.0):

    template <typename T>
    void foo(T)
    {
        static int x = 1;
        auto f = [] { return x + 1; };
        f();
    }

---

    /tmp/cc236Klq.o: In function `void
foo<int>(int)::{lambda()#1}::operator()() const':
    unmangled-ref.cpp:(.text+0x20): undefined reference to `x'
    collect2: error: ld returned 1 exit status

---

It *appears* we attempt to load x from the unmangled version:

    movl    _ZL1x(%rip), %eax

In g++ 4.6.3, you can work around this issue by explicitly capturing the static
variable:

    auto f = [&x] { return x + 1; };

So x is loaded from the fully-mangled name:

    movq    $_ZZ3fooIiEvT_E1x, -16(%rbp)

---

$> g++ -v
Using built-in specs.
COLLECT_GCC=g++-4.7
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.0-7ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --disable-bootstrap --with-sysroot=/
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--enable-gnu-unique-object --enable-plugin --enable-objc-gc --disable-werror
--with-arch-32=i686 --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.0 (Ubuntu/Linaro 4.7.0-7ubuntu3)

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler at
                   |                            |googlemail dot com

--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-08-16 06:20:47 UTC ---
The problem seems to be fixed in gcc 4.8.0 20120729 (experimental)

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|travis at gockelhut dot com |

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-08-19 12:09:54 UTC ---
Daniel can you please double check this one too? Today I'm definitely seeing
the undefined reference.

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

--- Comment #3 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-08-19 12:14:53 UTC ---
(In reply to comment #2)
> Daniel can you please double check this one too? Today I'm definitely seeing
> the undefined reference.

It seems that I need to fix my gcc installation as described in bug 54319 - my
apologies.

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-08-19
     Ever Confirmed|0                           |1

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-02-15 15:17:24 UTC ---
Just noticed that *the workaround* doesn't work anymore in 4.8/4.7, not sure if
this implies something interesting...

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> 2013-02-15 19:22:23 UTC ---
Author: jason
Date: Fri Feb 15 19:22:14 2013
New Revision: 196091

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196091
Log:
    PR c++/54276
    * semantics.c (finish_id_expression): Also return the identifier
    for an outer local static.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template9.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/semantics.c

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |
   Target Milestone|---                         |4.8.0

--- Comment #6 from Jason Merrill <jason at gcc dot gnu.org> 2013-02-15 19:23:32 UTC ---
Fixed for 4.8.

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> 2013-02-16 02:08:00 UTC ---
Author: jason
Date: Sat Feb 16 02:07:55 2013
New Revision: 196101

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196101
Log:
    PR c++/54276
    * semantics.c (finish_id_expression): Also return the identifier
    for an outer local static.

Added:
   
branches/gcc-4_7-branch/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template9.C
Modified:
    branches/gcc-4_7-branch/gcc/cp/ChangeLog
    branches/gcc-4_7-branch/gcc/cp/semantics.c

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.0                       |4.7.3

[Bug c++/54276] Lambda in a Template Function Undefined Reference to local static

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54276

--- Comment #8 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-02-16 09:24:11 UTC ---
... and 4.7.3 too.