[Bug c++/51812] New: Virtual public inheritance leads to "undefined reference" in header files.

[Bug c++/51812] New: Virtual public inheritance leads to "undefined reference" in header files.

[bredelin at ucla dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

             Bug #: 51812
           Summary: Virtual public inheritance leads to "undefined
                    reference" in header files.
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bredelin@ucla.edu


Created attachment 26292
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26292
The c++ file that has linker errors.

Hi,

Using gcc 4.7 causes new linker errors that are not present in e.g. 4.5, 4.6,
or clang.  These linker errors make it impossible to use header files that do
not fully define some classes entirely in the header file.  

The errors look like:

% g++-4.7 all5.C 

/tmp/ccfEMWL0.o: In function `Object::print() const':
all5.C:(.text._ZNK6Object5printEv[_ZNK6Object5printEv]+0x58): undefined
reference to `demangle(std::string const&)'


/tmp/ccfEMWL0.o: In function `alphabet::compare(Object const&) const':
all5.C:(.text._ZNK8alphabet7compareERK6Object[_ZNK8alphabet7compareERK6Object]+0x81):
undefined reference to `typeinfo for alphabet'
all5.C:(.text._ZNK8alphabet7compareERK6Object[_ZNK8alphabet7compareERK6Object]+0xa5):
undefined reference to `operator==(alphabet const&, alphabet const&)'


/tmp/ccfEMWL0.o: In function `alphabet::~alphabet()':
all5.C:(.text._ZN8alphabetD1Ev[_ZN8alphabetD1Ev]+0xe): undefined reference to
`vtable for alphabet'
all5.C:(.text._ZN8alphabetD1Ev[_ZN8alphabetD1Ev]+0x26): undefined reference to
`vtable for alphabet'


/tmp/ccfEMWL0.o: In function `Triplets::Triplets(Triplets const&)':
all5.C:(.text._ZN8TripletsC1ERKS_[_ZN8TripletsC1ERKS_]+0x3d): undefined
reference to `VTT for Triplets'
all5.C:(.text._ZN8TripletsC1ERKS_[_ZN8TripletsC1ERKS_]+0x51): undefined
reference to `vtable for Triplets'
all5.C:(.text._ZN8TripletsC1ERKS_[_ZN8TripletsC1ERKS_]+0x69): undefined
reference to `vtable for Triplets'
/tmp/ccfEMWL0.o:(.rodata._ZTV18AminoAcidsWithStop[_ZTV18AminoAcidsWithStop]+0x48):
undefined reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTV18AminoAcidsWithStop[_ZTV18AminoAcidsWithStop]+0x60):
undefined reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTV18AminoAcidsWithStop[_ZTV18AminoAcidsWithStop]+0x70):
undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_10AminoAcids[_ZTV18AminoAcidsWithStop]+0x48):
undefined reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_10AminoAcids[_ZTV18AminoAcidsWithStop]+0x60):
undefined reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_10AminoAcids[_ZTV18AminoAcidsWithStop]+0x70):
undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_8alphabet[_ZTV18AminoAcidsWithStop]+0x30):
undefined reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_8alphabet[_ZTV18AminoAcidsWithStop]+0x48):
undefined reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_8alphabet[_ZTV18AminoAcidsWithStop]+0x60):
undefined reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC18AminoAcidsWithStop0_8alphabet[_ZTV18AminoAcidsWithStop]+0x70):
undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTV10AminoAcids[_ZTV10AminoAcids]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTV10AminoAcids[_ZTV10AminoAcids]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTV10AminoAcids[_ZTV10AminoAcids]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTC10AminoAcids0_8alphabet[_ZTV10AminoAcids]+0x30):
undefined reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTC10AminoAcids0_8alphabet[_ZTV10AminoAcids]+0x48):
undefined reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC10AminoAcids0_8alphabet[_ZTV10AminoAcids]+0x60):
undefined reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC10AminoAcids0_8alphabet[_ZTV10AminoAcids]+0x70):
undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTV3RNA[_ZTV3RNA]+0x48): undefined reference to
`alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTV3RNA[_ZTV3RNA]+0x60): undefined reference to
`alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTV3RNA[_ZTV3RNA]+0x70): undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_11Nucleotides[_ZTV3RNA]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_11Nucleotides[_ZTV3RNA]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_11Nucleotides[_ZTV3RNA]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_8alphabet[_ZTV3RNA]+0x30): undefined
reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_8alphabet[_ZTV3RNA]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_8alphabet[_ZTV3RNA]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC3RNA0_8alphabet[_ZTV3RNA]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTV3DNA[_ZTV3DNA]+0x48): undefined reference to
`alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTV3DNA[_ZTV3DNA]+0x60): undefined reference to
`alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTV3DNA[_ZTV3DNA]+0x70): undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_11Nucleotides[_ZTV3DNA]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_11Nucleotides[_ZTV3DNA]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_11Nucleotides[_ZTV3DNA]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_8alphabet[_ZTV3DNA]+0x30): undefined
reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_8alphabet[_ZTV3DNA]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_8alphabet[_ZTV3DNA]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC3DNA0_8alphabet[_ZTV3DNA]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTV11Nucleotides[_ZTV11Nucleotides]+0x48): undefined
reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTV11Nucleotides[_ZTV11Nucleotides]+0x60): undefined
reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTV11Nucleotides[_ZTV11Nucleotides]+0x70): undefined
reference to `alphabet::get_frequencies_from_counts(std::valarray<double>
const&, double) const'
/tmp/ccfEMWL0.o:(.rodata._ZTC11Nucleotides0_8alphabet[_ZTV11Nucleotides]+0x30):
undefined reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTC11Nucleotides0_8alphabet[_ZTV11Nucleotides]+0x48):
undefined reference to `alphabet::print() const'
/tmp/ccfEMWL0.o:(.rodata._ZTC11Nucleotides0_8alphabet[_ZTV11Nucleotides]+0x60):
undefined reference to `alphabet::setup_letter_classes()'
/tmp/ccfEMWL0.o:(.rodata._ZTC11Nucleotides0_8alphabet[_ZTV11Nucleotides]+0x70):
undefined reference to
`alphabet::get_frequencies_from_counts(std::valarray<double> const&, double)
const'
/tmp/ccfEMWL0.o:(.rodata._ZTI10AminoAcids[_ZTI10AminoAcids]+0x10): undefined
reference to `typeinfo for alphabet'
/tmp/ccfEMWL0.o:(.rodata._ZTI11Nucleotides[_ZTI11Nucleotides]+0x10): undefined
reference to `typeinfo for alphabet'
collect2: error: ld returned 1 exit status

All the errors go away if you change class alphabet to not have virtual public
inheritance, by removing the word "virtual".

[Bug c++/51812] Virtual public inheritance leads to "undefined reference" in header files.

[bredelin at ucla dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #1 from bredelin at ucla dot edu 2012-01-10 14:32:46 UTC ---
Created attachment 26293
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26293
Preprocessed source

[Bug c++/51812] Virtual public inheritance leads to "undefined reference" in header files.

[bredelin at ucla dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #2 from bredelin at ucla dot edu 2012-01-10 15:09:09 UTC ---
Also note that the bug report is based on a snapshot of 4.7 that was taken on
Jan 7, 2012.

$ g++-4.7 -v
Using built-in specs.
COLLECT_GCC=/usr/bin/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='Debian 4.7-20120107-1'
--with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++,go --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 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-plugin --enable-objc-gc
--with-arch-32=i586 --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 20120107 (experimental) [trunk revision 182981] (Debian
4.7-20120107-1)

[Bug c++/51812] [4.7 regression] Virtual public inheritance leads to "undefined reference" in header files.

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-22
                 CC|                            |jason at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-01-22 20:15:00 UTC ---
Confirmed.

[Bug c++/51812] [4.7 regression] Virtual public inheritance leads to "undefined reference" in header files.

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.7.0

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|x86_64-linux-gnu            |
                 CC|                            |hubicka at gcc dot gnu.org
               Host|x86_64-linux-gnu            |
            Summary|[4.7 regression] Virtual    |[4.7 regression] Virtual
                   |public inheritance leads to |public inheritance and
                   |"undefined reference" in    |thunks leads to "undefined
                   |header files.               |reference" in header files.
              Build|x86_64-linux-gnu            |

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-22 21:42:38 UTC ---
Reduced testcase:
class Object {
  virtual Object* clone() const =0;
  virtual char* print() const;
};
class alphabet: virtual public Object{};
class Nucleotides: public alphabet {};
class DNA: public Nucleotides {
  virtual DNA* clone() const {return new DNA(*this);}
};
int main() { }
--- CUT ---
This testcase requires thunks and virtual inheritance.

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

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

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

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-23 18:05:01 UTC ---
Patch at http://gcc.gnu.org/ml/gcc-patches/2012-01/msg01160.html

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[bredelin at ucla dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #6 from bredelin at ucla dot edu 2012-01-23 22:46:47 UTC ---
I will check this patch tomorrow (Jan 24th) to make sure that it fixes the
problem on non-reduced test cases.

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-24 13:37:43 UTC ---
Author: jason
Date: Tue Jan 24 13:37:38 2012
New Revision: 183475

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183475
Log:
    PR c++/51812
    * cgraphunit.c (cgraph_decide_is_function_needed): Don't always
    output static aliases.

Added:
    trunk/gcc/testsuite/g++.dg/inherit/covariant20.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cgraphunit.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-24 13:38:13 UTC ---
Fixed.

[Bug c++/51812] [4.7 regression] Virtual public inheritance and thunks leads to "undefined reference" in header files.

[bredelin at ucla dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51812

--- Comment #9 from bredelin at ucla dot edu 2012-01-29 18:30:43 UTC ---
Thanks :-)