[Bug c++/19474] New: wrong tree for extern "C" variables

[Bug c++/19474] New: wrong tree for extern "C" variables

[sstrasser at systemhaus-gruppe dot de]

I don't know if this ever has an effect on an output of gcc(are C variable names
ever different from C++ ones?), but there are two different trees which should
be equal:
example1:
extern "C"{ extern int a; }
extern "C"{ int a; }
example2:
extern "C"{ extern int a; }
int a;

those should be equal I think, but "a" is not DECL_EXTERN_C_P for example2.
if "a" is a function it is DECL_EXTERN_C_P in both examples.

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           Summary: wrong tree for extern "C" variables
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sstrasser at systemhaus-gruppe dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-16 23:40 -------
I don't know if there is a bug here or not.

But note normal variables in the global namespace are not mangled either.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-16 23:44 -------
Also the only use of DECL_EXTERN_C_P for variable decls is when mangling (this is unlike functions).

So what are you trying to do here?

I would suspect there is a bug, but a very latent bug which does not show up in the normaling 
compiling of things.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[sstrasser at systemhaus-gruppe dot de]

------- Additional Comments From sstrasser at systemhaus-gruppe dot de  2005-01-16 23:55 -------
I totally agree that this is not important.
I just don't know gcc good enough to forecast the possible effects of that minor
bug so I thought it'd be interesting.

please close the bug if you are sure it doesn't have any effects on compilation.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[schlie at comcast dot net]

------- Additional Comments From schlie at comcast dot net  2005-01-17 01:35 -------
(In reply to comment #3)

Or might it be nearly just as easy to place all in the same tree initially,
and eliminate the potential ambiguity now that it's been identified?



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[mueller at kde dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mueller at kde dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong tree for extern "C" variables

[sstrasser at systemhaus-gruppe dot de]

------- Additional Comments From sstrasser at systemhaus-gruppe dot de  2005-01-31 07:48 -------
I think I was wrong, this is a bug _and_ has effects on compilation:

in example2(see above) int a is not extern "C" in the tree, AND it is C++
mangled in compiler output!

std 7.5.7 states that a once declared extern "C" function is extern "C" even if
defined without linkage specification. I can't find the same for variables, but
since this is a redeclaration that must be the true:
extern "C"{ extern int a; }
int a;
extern "C"{ int a; }

I've attached a simple test case. link it and you'll get an undefined reference
to "a".

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|minor                       |normal


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong linkage of extern "C" variables

[sstrasser at systemhaus-gruppe dot de]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|wrong tree for extern "C"   |wrong linkage of extern "C"
                   |variables                   |variables


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong linkage of extern "C" variables

[sstrasser at systemhaus-gruppe dot de]

------- Additional Comments From sstrasser at systemhaus-gruppe dot de  2005-01-31 07:52 -------
Created an attachment (id=8111)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8111&action=view)
reference to a in c.c shouldn't be undefined


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474

[Bug c++/19474] wrong linkage of extern "C" variables

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-31 14:58 -------
Actually the code is invalid, see PR 6548 which this is a dup of.

*** This bug has been marked as a duplicate of 6548 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19474