[Bug c++/54801] New: [c++11] static variables constructed with lambda params inside member functions cause undefined errors

["matt at godbolt dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54801

             Bug #: 54801
           Summary: [c++11] static variables constructed with lambda
                    params inside member functions cause undefined errors
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: matt@godbolt.org


Created attachment 28346
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28346
Test C file exhibiting the issue

In the attached code, there is static method with a static variable whose
constructor takes a function pointer.  When a lambda is passed as the function
pointer, it seems the lambda's definition is dropped and the result is a
link-time error.

$ g++ -o test -std=c++0x test.cc
/tmp/ccpBFtG7.o: In function `Test::aFunc()::{lambda(int*)#1}::operator void
(*)(int*)() const':
test.cc:(.text._ZZN4Test5aFuncEvENKUlPiE_cvPFvS0_EEv[_ZZN4Test5aFuncEvENKUlPiE_cvPFvS0_EEv]+0x9):
undefined reference to `Test::aFunc()::{lambda(int*)#1}::_FUN(int*)'
collect2: error: ld returned 1 exit status

Making the variable non-static fixes the issue.  The same code in a free
function does not exhibit the problem.  Taking a std::function<void(int*)> as
the constructor parameter also cures the issue.  It seems to be something which
only throws away the lambda for static variables inside member functions.

More info:

g++ -v
Using built-in specs.
COLLECT_GCC=/site/apps/gcc-4.7.2-drw.patched.1/bin/g++
COLLECT_LTO_WRAPPER=/site/apps/gcc-4.7.2-drw.patched.1/libexec/gcc/x86_64-linux-gnu/4.7.2/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ./configure --prefix /site/apps/gcc-4.7.2-drw.patched.1
--build=x86_64-linux-gnu --enable-clocale=gnu --enable-gold
--enable-languages=c,c++ --enable-ld=default --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-linker-build-id --enable-lto
--enable-plugin --enable-shared --enable-threads=posix --host=x86_64-linux-gnu
--target=x86_64-linux-gnu --with-pkgversion=DRW-internal-build
--with-plugin-ld=ld.gold --with-system-zlib
--with-gmp=/data/teamcity/work/sup-chietfbld02-002/8a981abc13d5c0c5/scratch/gcc/4.7.2/build/gmp-5.0.2
--with-mpfr=/data/teamcity/work/sup-chietfbld02-002/8a981abc13d5c0c5/scratch/gcc/4.7.2/build/mpfr-3.1.1
--with-mpc=/data/teamcity/work/sup-chietfbld02-002/8a981abc13d5c0c5/scratch/gcc/4.7.2/build/mpc-0.9
--with-libelf=/data/teamcity/work/sup-chietfbld02-002/8a981abc13d5c0c5/scratch/gcc/4.7.2/build/libelf-0.8.9
Thread model: posix
gcc version 4.7.2 (DRW-internal-build) 

This issue was discovered when attempting to register lambda functions as the
"cleanup function" for static thread-local stored information using
boost::thread_specific_ptr. However, the issue is reproducible in the attached
source file with no external includes.

This appears to be a regression in 4.7.2: gcc versions 4.7.1, 4.7.0, 4.6.3 and
4.5.3 compile the source without issue.