[Bug c++/55015] New: Lambda functions not found at link time when declared in an inline function

[Bug c++/55015] New: Lambda functions not found at link time when declared in an inline function

[julien.nitard at m4tp dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

             Bug #: 55015
           Summary: Lambda functions not found at link time when declared
                    in an inline function
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: julien.nitard@m4tp.org


Hi all,

Following this stackoverflow question
http://stackoverflow.com/questions/13003941/lambda-not-found-when-defined-in-an-inline-function-in-g-4-7,
I was directed here to report a bug.
I have tried to find similar bugs but haven't.

Lambdas are not handled properly when declared inside inline functions (or so
it seems).

Here is a LWS link that demonstrates the error:
http://liveworkspace.org/code/35374b3c9b0d40e8ccc0819eb44d7f9e


In case the link disappears, here the source:

#include <stdexcept>
#include <string>

#include <boost/algorithm/string.hpp>

using std::string;

typedef bool (*FieldComparer)(const std::string&, const std::string&);

inline FieldComparer
GetComparer(const std::string& query, string& separator)
{
    if (query.find('=') != std::string::npos) {
        separator = "=";
        return [](const string& s1, const string& s2) { return s1 == s2; };
    }
    else if (query.find('^') != string::npos) {
        separator = "^";
        return [](const string& s1, const string& s2) { return
boost::starts_with(s1, s2); };
    }
    else if (query.find('*') != string::npos) {
        separator = "*";
        return [](const string& s1, const string& s2) { return
boost::contains(s1, s2); };
    }
    else if (query.find('!') != string::npos) {
        separator = "!";
        return [](const string& s1, const string& s2) { return s1 != s2; };
    }
    else
        throw std::invalid_argument("Search: could not find operator in query
string.");
}

int main()
{
  std::string sep;
  auto comp = GetComparer( "=", sep );
}

Many thanks,

[Bug c++/55015] Lambda functions not found at link time when declared in an inline function

[julien.nitard at m4tp dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

--- Comment #1 from Julien Nitard <julien.nitard at m4tp dot org> 2012-10-22 02:13:43 UTC ---
Somebody noted in S.O. that declaring the inline function "static" (or using an
anonymous namespace which I guess as same effect) hides (or solves ;) the
problem.

[Bug c++/55015] Lambda functions not found at link time when declared in an inline function

[spam_hole at shaw dot ca]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

Robert Xiao <spam_hole at shaw dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |spam_hole at shaw dot ca

--- Comment #2 from Robert Xiao <spam_hole at shaw dot ca> 2012-10-22 05:02:01 UTC ---
Minimal reproducible testcase:

    typedef void (*VoidFunc)();
    inline VoidFunc GetFunc() { return [](){}; }
    int main() { VoidFunc func = GetFunc(); }

Compiled with gcc version 4.7.2 (MacPorts gcc47 4.7.2_2). Output:

$ g++-mp-4.7 test.cpp -std=c++11
Undefined symbols for architecture x86_64:
  "GetFunc()::{lambda()#1}::_FUN()", referenced from:
      GetFunc()::{lambda()#1}::operator void (*)()() const in cciEeUag.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

[Bug c++/55015] Lambda functions not found at link time when declared in an inline function

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |assemble-failure
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-22
                 CC|                            |pinskia at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-10-22 05:09:36 UTC ---
Confirmed on the trunk too.

[Bug c++/55015] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |icegood1980 at gmail dot
                   |                            |com

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-02 11:10:49 UTC ---
*** Bug 55178 has been marked as a duplicate of this bug. ***

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Lambda functions not found  |[4.7/4.8 Regression] Lambda
                   |at link time when declared  |functions not found at link
                   |in an inline function       |time when declared in an
                   |                            |inline function

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-26 23:37:48 UTC ---
This is a regression.

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com

--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-27 10:26:03 UTC ---
HJ, can you help finding which change broke this? In Comment #2 there is a very
short testcase (it's pretty old, I guess you want -std=c++0x, not -std=c++11 in
the command line)

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |4.8.0

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-27 11:00:54 UTC ---
http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=189175

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

--- Comment #8 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-27 11:02:42 UTC ---
Never mind, it's very easy, it's the following change, the fix for PR53821:

   http://gcc.gnu.org/viewcvs?view=revision&revision=189176

And PR55472 is a duplicate, reverting the above fixes it too.

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |walker_643 at yahoo dot com

--- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-27 11:03:54 UTC ---
*** Bug 55472 has been marked as a duplicate of this bug. ***

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |jason at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |f.heckenbach@fh-soft.de

--- Comment #10 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-12-06 11:32:25 UTC ---
*** Bug 55607 has been marked as a duplicate of this bug. ***

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

--- Comment #11 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-06 14:37:23 UTC ---
Author: jason
Date: Thu Dec  6 14:37:13 2012
New Revision: 194251

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194251
Log:
    PR c++/55015
    PR c++/53821
    * semantics.c (maybe_add_lambda_conv_op): Revert earlier change.
    * decl.c (start_preparsed_function): Make local class methods comdat
    in templates, too.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv6.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/semantics.c

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

--- Comment #12 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-06 14:39:57 UTC ---
Author: jason
Date: Thu Dec  6 14:39:52 2012
New Revision: 194253

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194253
Log:
    PR c++/55015
    PR c++/53821
    * semantics.c (maybe_add_lambda_conv_op): Revert earlier change.
    * decl.c (start_preparsed_function): Make local class methods comdat
    in templates, too.

Added:
    branches/gcc-4_7-branch/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv6.C
Modified:
    branches/gcc-4_7-branch/gcc/cp/ChangeLog
    branches/gcc-4_7-branch/gcc/cp/decl.c
    branches/gcc-4_7-branch/gcc/cp/semantics.c

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.8.0                       |4.7.3

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-06 14:42:45 UTC ---
Fixed for 4.7.3.

[Bug c++/55015] [4.7/4.8 Regression] Lambda functions not found at link time when declared in an inline function

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55015

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matt at godbolt dot org

--- Comment #14 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-12-06 15:44:50 UTC ---
*** Bug 54801 has been marked as a duplicate of this bug. ***