[Bug c++/16171] New: Problems when deriving from basic stream classes

[Bug c++/16171] New: Problems when deriving from basic stream classes

[mark at emantic dot co dot uk]

Deriving from basic stream classes fails when: 
The name of the derived class is the same as the base class except that it is 
in a different namespace. 
 
The problem can be demonstrated using the following example (test.cpp): 
 
include <iostream> 
 
namespace mar { 
 
    template <typename charT, 
        typename char_traitsT = std::char_traits<charT> > 
    class basic_iostream 
    :   public std::basic_iostream<charT, char_traitsT> { 
    public: 
        basic_iostream() 
        :   std::basic_iostream<charT, char_traitsT>(0) 
        { 
        } 
    }; 
} 
 
int 
main(int argc, char* argv[]) 
{ 
    mar::basic_iostream<char> strm; 
    return 0; 
} 
 
$ g++ test.cpp 
test.cpp: In instantiation of `mar::basic_iostream<char, 
std::char_traits<char> >': 
test.cpp:20:   instantiated from here 
test.cpp:8: internal error: Segmentation fault 
Please submit a full bug report, 
with preprocessed source if appropriate. 
See <URL:http://gcc.gnu.org/bugs.html> for instructions. 
 
$ gcc -v 
Reading specs from /usr/lib/gcc-lib/i486-slackware-linux/3.2.3/specs 
Configured with: ../gcc-3.2.3/configure --prefix=/usr --enable-shared 
--enable-threads=posix --enable-__cxa_atexit --disable-checking --with-gnu-ld 
--verbose --target=i486-slackware-linux --host=i486-slackware-linux 
Thread model: posix 
gcc version 3.2.3 
 
This problem can be avoided by renaming the derived class to something other 
than basic_iostream.

-- 
           Summary: Problems when deriving from basic stream classes
           Product: gcc
           Version: 3.2.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mark at emantic dot co dot uk
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i486-slackware-linux
  GCC host triplet: i486-slackware-linux
GCC target triplet: i486-slackware-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] Problems when deriving from basic stream classes

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-24 08:11 -------
The ICE is fixed in 3.3.3 but this produces wrong in 3.3.3, 3.4.0, and 3.5.0:
pr16171.s: Assembler messages:
pr16171.s:609: Error: symbol `_ZTVSd' is already defined
pr16171.s:630: Error: symbol `_ZTTSd' is already defined
pr16171.s:643: Error: symbol `_ZTCSd0_Si' is already defined
pr16171.s:659: Error: symbol `_ZTCSd8_So' is already defined
pr16171.s:787: Error: symbol `_ZNSdD1Ev' is already defined
pr16171.s:913: Error: symbol `_ZTv0_n12_NSdD1Ev' is already defined
pr16171.s:924: Error: symbol `_ZThn8_NSdD1Ev' is already defined
pr16171.s:932: Error: symbol `_ZNSdD0Ev' is already defined
pr16171.s:1058: Error: symbol `_ZTv0_n12_NSdD0Ev' is already defined
pr16171.s:1069: Error: symbol `_ZThn8_NSdD0Ev' is already defined

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |wrong-code
      Known to fail|                            |3.3.3 3.4.0 3.5.0
   Last reconfirmed|0000-00-00 00:00:00         |2004-06-24 08:11:16
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] Problems when deriving from basic stream classes

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2004-06-24 14:16 -------
Here's a reduced testcase which causes assembler errors since gcc 3.3:

=============================================================================
struct A {};

namespace std
{
    template<typename> struct char_traits;

    template<typename, typename> struct basic_iostream : virtual A {};
}

template <typename T, typename U = std::char_traits<T> > struct basic_iostream
  : std::basic_iostream<T, U> {};

basic_iostream<char> s;
=============================================================================

With mainline, for example, I get:

/tmp/ccmexVtk.s: Assembler messages:
/tmp/ccmexVtk.s:124: Error: symbol `_ZTVSd' is already defined
/tmp/ccmexVtk.s:133: Error: symbol `_ZTTSd' is already defined


What really strikes me is the fact that the errors go away if I replace
"std" or "char_traits" or "basic_iostream" by a different name.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-06-25 13:35 -------
Remember that some names in std:: (and namespace std::) are mangled  
specially to save space. For example, the symbol _ZNSdC1Ev demangles 
to 
  std::basic_iostream<char, std::char_traits<char> >::basic_iostream() 
If the names were different, then they would appear in the mangled 
names. 
 
Thus, this looks like an ABI problem to me. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Problems when deriving from |[ABI] Problems with standard
                   |basic stream classes        |names in different
                   |                            |namespaces


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[bkoz at gcc dot gnu dot org]

------- Additional Comments From bkoz at gcc dot gnu dot org  2004-07-01 17:19 -------

I can confirm this as well. 

This looks to be a problem with the mangling code: the mar::basic_iostream class
should be mangled differently than std::basic_iostream. Perhaps g++ is not
checking the enclosing namespace before using the C++ ABI substitutions? Hmm.

FYI icc does this, which is as I'd expect

_ZN3mar14basic_iostreamIcSt11char_traitsIcEEC9Ev

-benjamin

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-05-20 13:36 -------
The original testcase and the testcase from comment #2 compile on mainline.
The underlying ABI problem still remains, however.

The following updated testcase still gives assembler errors on mainline:

===========================================================================
namespace std
{
    template<typename> struct char_traits;

    template<typename, typename> struct basic_iostream { basic_iostream(){} };
    basic_iostream<char,std::char_traits<char> > s1;
}

template<typename, typename> struct basic_iostream { basic_iostream(){} };
basic_iostream<char,std::char_traits<char> > s2;
===========================================================================


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-09-13 15:16 -------
Subject: Bug 16171

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	mmitchel@gcc.gnu.org	2005-09-13 15:15:37

Modified files:
	gcc/cp         : ChangeLog mangle.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/abi: mangle26.C mangle27.C mangle28.C 
	                          mangle29.C 

Log message:
	PR c++/16171
	* mangle.c (find_substitution): Do not use special substitutions
	for identifiers not in std::.
	
	PR c++/16171
	* g++.dg/abi/mangle26.C: New test.
	* g++.dg/abi/mangle27.C: New test.
	* g++.dg/abi/mangle28.C: New test.
	* g++.dg/abi/mangle29.C: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.4889&r2=1.4890
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/mangle.c.diff?cvsroot=gcc&r1=1.127&r2=1.128
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.6057&r2=1.6058
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle26.C.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle27.C.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle28.C.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle29.C.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-09-13 15:17 -------
Subject: Bug 16171

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-4_0-branch
Changes by:	mmitchel@gcc.gnu.org	2005-09-13 15:17:12

Modified files:
	gcc/cp         : ChangeLog mangle.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/abi: mangle26.C mangle27.C mangle28.C 
	                          mangle29.C 

Log message:
	PR c++/16171
	* g++.dg/abi/mangle26.C: New test.
	* g++.dg/abi/mangle27.C: New test.
	* g++.dg/abi/mangle28.C: New test.
	* g++.dg/abi/mangle29.C: New test.
	
	PR c++/16171
	* mangle.c (find_substitution): Do not use special substitutions
	for identifiers not in std::.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.4648.2.103&r2=1.4648.2.104
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/mangle.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.116&r2=1.116.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.5084.2.403&r2=1.5084.2.404
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle26.C.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle27.C.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle28.C.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/abi/mangle29.C.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171

[Bug c++/16171] [ABI] Problems with standard names in different namespaces

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2005-09-13 15:19 -------
Fixed in GCC 4.0.2.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.0.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16171