c++/1877: gcc-20010122 and gcc-20010205 cause linker errors with static const int

[spencer at infointeractive dot com]

>Number:         1877
>Category:       c++
>Synopsis:       gcc-20010122 and gcc-20010205 cause linker errors with static const int
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 05 11:16:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Brad Spencer
>Release:        20010122 and 20010205
>Organization:
>Environment:
$ uname -a; /opt/gcc-20010122/bin/g++ -v
SunOS starbug 5.6 Generic_105182-05 i86pc i386 i86pc
Reading specs from /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/specs
Configured with: ../gcc-20010122/configure --prefix=/opt/gcc-20010122 --enable-languages=c++
gcc version 2.97 20010122 (experimental)
>Description:
Code that uses the ternary operator (?:) with a "static const int" class data member in a certain way causes a strange linker error.  Using "if-then" logic instead of "?:" or using an unsigned integer avoids the error.

Complete source (no includes) of an example follows.

// BEGIN

class A
{
public:
  A() : var(2), flag(false) {}

  static const int c = 1;
  int var;
  bool flag;

public:
  int f() const { return flag ? var : c; }
};

int main()
{
  A object;
  const int e = object.f();
  return e;
}

// END

Changing the definiton of the function "f" to

  int f() const { if(flag) return var; return c; }

_or_ the definition of the constant "c" to

  static const unsigned int c = 1;

does not generate the error.

I used the codesourcery online compiler to try gcc-20010205 and my own installation for gcc-20010122.

$ /opt/gcc-20010122/bin/g++ -v foo.cc
Reading specs from /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/specs
Configured with: ../gcc-20010122/configure --prefix=/opt/gcc-20010122 --enable-languages=c++
gcc version 2.97 20010122 (experimental)
 /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/cc1plus -v -D__GNUC__=2 -D__GNUC_MINOR__=97 -D__GNUC_PATCHLEVEL__=0 -Dunix -D__svr4__ -D__SVR4 -Dsun -D__unix__ -D__svr4__ -D__SVR4 -D__sun__ -D__unix -D__sun -Asystem=svr4 -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i386__ foo.cc -D__GNUG__=2 -D_GNU_SOURCE -D__GXX_ABI_VERSION=100 -quiet -dumpbase foo.cc -version -o /var/tmp/ccu1T5ZL.s
GNU CPP version 2.97 20010122 (experimental) (cpplib) (i386 System V Release 4)
GNU CPP version 2.97 20010122 (experimental) (cpplib) (i386 System V Release 4)
GNU C++ version 2.97 20010122 (experimental) (i386-pc-solaris2.6)
        compiled by GNU C version 2.95.2 19991024 (release).
#include "..." search starts here:
#include <...> search starts here:
 /opt/gcc-20010122/include/g++-v3
 /opt/gcc-20010122/i386-pc-solaris2.6/include/g++-v3
 /opt/gcc-20010122/include
 /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/include
 /opt/gcc-20010122/i386-pc-solaris2.6/include
 /usr/include
End of search list.
 /usr/ccs/bin/as -V -Qy -s -o /var/tmp/ccG26AGw.o /var/tmp/ccu1T5ZL.s
GNU assembler version 2.10 (i386-pc-solaris2.6) using BFD version 2.10
 /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/collect2 -V -Y P,/usr/ccs/lib:/usr/lib -Qy /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/crt1.o /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/crti.o /usr/ccs/lib/values-Xa.o /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/crtbegin.o -L/opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97 -L/usr/ccs/bin -L/usr/ccs/lib -L/opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/../../.. /var/tmp/ccG26AGw.o -lstdc++ -lm -lgcc -lc -lgcc /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/crtend.o /opt/gcc-20010122/lib/gcc-lib/i386-pc-solaris2.6/2.97/crtn.o
/var/tmp/ccG26AGw.o: In function `A::f() const':
/var/tmp/ccG26AGw.o(.gnu.linkonce.t._ZNK1A1fEv+0x1d): undefined reference to `A::c    '
GNU ld version 2.10 (with BFD 2.10)
  Supported emulations:
   elf_i386
collect2: ld returned 1 exit status

---------

Reading specs from /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/specs
Configured with: ../configure --prefix=/tmp/gcc-20010205-root/usr/local --enable-shared --enable-threads --disable-checking i386-pc-linux-gnu : (reconfigured)
gcc version 2.97 20010205 (experimental)
 /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/cc1plus -v -iprefix /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/ -D__GNUC__=2 -D__GNUC_MINOR__=97 -D__GNUC_PATCHLEVEL__=0 -D__ELF__ -Dunix -Dlinux -D__ELF__ -D__unix__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i386__ /tmp/@933.7.cc -D__GNUG__=2 -D_GNU_SOURCE -D__GXX_ABI_VERSION=100 -quiet -dumpbase @933.7.cc -version -o /tmp/ccpehC9e.s
GNU CPP version 2.97 20010205 (experimental) (cpplib) (i386 Linux/ELF)
GNU CPP version 2.97 20010205 (experimental) (cpplib) (i386 Linux/ELF)
GNU C++ version 2.97 20010205 (experimental) (i386-pc-linux-gnu)
compiled by GNU C version 2.97 20010205 (experimental).
ignoring nonexistent directory "/usr/local/include/g++-"
ignoring nonexistent directory "/usr/local/i386-pc-linux-gnu/include/g++-"
ignoring nonexistent directory "/tmp/gcc-20010205-root/usr/local/include/g++-"
ignoring nonexistent directory "/tmp/gcc-20010205-root/usr/local/i386-pc-linux-gnu/include/g++-"
ignoring nonexistent directory "/tmp/gcc-20010205-root/usr/local/lib/gcc-lib/i386-pc-linux-gnu/2.97/include"
ignoring nonexistent directory "/tmp/gcc-20010205-root/usr/local/i386-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/lib/gcc-lib/i386-pc-linux-gnu/2.97/include
 /usr/local/i386-pc-linux-gnu/include
 /usr/local/include
 /usr/include
End of search list.
/tmp/@933.7.cc:21:1: warning: no newline at end of file
 as -V -Qy -o /tmp/cczmn0Hk.o /tmp/ccpehC9e.s
GNU assembler version 2.9.1 (i386-redhat-linux), using BFD version 2.9.1.0.24
 /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/collect2 -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -o /tmp/@933.8 /usr/lib/crt1.o /usr/lib/crti.o /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/crtbegin.o -L/usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97 -L/usr/local/bin/../lib/gcc-lib -L/usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/../../.. /tmp/cczmn0Hk.o -lstdc++ -lm -lgcc -lc -lgcc /usr/local/bin/../lib/gcc-lib/i386-pc-linux-gnu/2.97/crtend.o /usr/lib/crtn.o
/tmp/cczmn0Hk.o: In function `A::f() const':
/tmp/cczmn0Hk.o(.gnu.linkonce.t._ZNK1A1fEv+0x1d): undefined reference to `A::c    '
collect2: ld returned 1 exit status

--------

It works with gcc-2.95.2.

$ g++ -v foo.cc
Reading specs from /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/specs
gcc version 2.95.2 19991024 (release)
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/cpp -lang-c++ -v -D__GNUC__=2 -D__GNUG__=2 -D__GNUC_MINOR__=95 -D__cplusplus -Dunix -D__svr4__ -D__SVR4 -Dsun -D__unix__ -D__svr4__ -D__SVR4 -D__sun__ -D__unix -D__sun -Asystem(svr4) -D__EXCEPTIONS -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ foo.cc /var/tmp/ccigX8Yq.ii
GNU CPP version 2.95.2 19991024 (release) (i386 System V Release 4)
#include "..." search starts here:
#include <...> search starts here:
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/../../../../include/g++-3
 /usr/local/include
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/../../../../i386-pc-solaris2.6/include
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/include
 /usr/include
End of search list.
The following default directories have been omitted from the search path:
End of omitted list.
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/cc1plus /var/tmp/ccigX8Yq.ii -quiet -dumpbase foo.cc -version -o /var/tmp/ccgRopdJ.s
GNU C++ version 2.95.2 19991024 (release) (i386-pc-solaris2.6) compiled by GNU C version 2.95.2 19991024 (release).
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/as -V -Qy -o /var/tmp/ccCcMyD2.o /var/tmp/ccgRopdJ.s
GNU assembler version 2.9.1 (i386-pc-solaris2.6), using BFD version 2.9.1
 /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/collect2 -V -Y P,/usr/ccs/lib:/usr/lib -Qy /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/crt1.o /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/crti.o /usr/ccs/lib/values-Xa.o /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/crtbegin.o -L/opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2 -L/usr/ccs/bin -L/usr/ccs/lib -L/opt/gcc-2.95.2/lib /var/tmp/ccCcMyD2.o -lstdc++ -lm -lgcc -lc -lgcc /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/crtend.o /opt/gcc-2.95.2/lib/gcc-lib/i386-pc-solaris2.6/2.95.2/crtn.o
GNU ld version 2.10 (with BFD 2.10)
  Supported emulations:
   elf_i386
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: