[Bug c++/20357] New: Multiply defined assembler symbols for template instantiations

[Bug c++/20357] New: Multiply defined assembler symbols for template instantiations

[heinlein at informatik dot uni-ulm dot de]

The following code produces the assembler message: 
"Error: symbol `_ZN1XIXadL_Z1fvEEEC1Ev' is already defined". 
If the declaration of f in main is omitted, everything is fine. 
 
typedef void (*Func) (); 
template <Func f> 
struct X { X () {} }; 
void f () {} 
X<f> x; 
int main () { 
  void f (); 
  X<f> x; 
}

-- 
           Summary: Multiply defined assembler symbols for template
                    instantiations
           Product: gcc
           Version: 3.3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: heinlein at informatik dot uni-ulm dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20357

[Bug c++/20357] Multiply defined assembler symbols for template instantiations

[lerdsuwa at gcc dot gnu dot org]

------- Additional Comments From lerdsuwa at gcc dot gnu dot org  2005-03-07 14:29 -------
Confirm as a bug.  It's still present in the mainline.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-03-07 14:29:51
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20357

[Bug c++/20357] Multiply defined assembler symbols for template instantiations

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-03-07 15:11 -------
What is happening here is that multiple decls for f is getting in the way.  Either we have to look at the 
DECL_UID or change the C++ front-end to only have one decl for f.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20357

[Bug c++/20357] Multiply defined assembler symbols for template instantiations

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=20357

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Just for reference here is the ICE that is produced:
```
<source>:10:1: error: Two symbols with same comdat_group are not linked by the
same_comdat_group list.
   10 | }
      | ^
_ZN1XIXadL_Z1fvEEEC1Ev/8 (X<f>::X() [with void (* f)() = f])
  Type: function definition analyzed alias cpp_implicit_alias
  Visibility: semantic_interposition public weak comdat
comdat_group:_ZN1XIXadL_Z1fvEEEC5Ev one_only
  Same comdat group as: _ZN1XIXadL_Z1fvEEEC2Ev/7
  previous sharing asm name: 5
  References: _ZN1XIXadL_Z1fvEEEC2Ev/7 (alias) 
  Referring: 
  Function flags:
  Called by: main/2 
  Calls: 
_ZN1XIXadL_Z1fvEEEC1Ev/5 (X<f>::X() [with void (* f)() = f])
  Type: function definition analyzed alias cpp_implicit_alias
  Visibility: semantic_interposition public weak comdat
comdat_group:_ZN1XIXadL_Z1fvEEEC5Ev one_only
  Same comdat group as: _ZN1XIXadL_Z1fvEEEC2Ev/4
  next sharing asm name: 8
  References: _ZN1XIXadL_Z1fvEEEC2Ev/4 (alias) 
  Referring: 
  Function flags:
  Called by: _Z41__static_initialization_and_destruction_0v/9 
  Calls: 

```