[c++] Another question about demangler output

[Daniel Jacobowitz]

On Sun, Dec 07, 2003 at 06:05:58AM +0100, Gabriel Dos Reis wrote:
> Ian Lance Taylor <ian@wasabisystems.com> writes:
> 
> | Gabriel Dos Reis <gdr@integrable-solutions.net> writes:
> | 
> | > Ian Lance Taylor <ian@wasabisystems.com> writes:
> | > 
> | > | Gabriel Dos Reis <gdr@integrable-solutions.net> writes:
> | > | 
> | > | > The point is this.  "typeof" is a GNU/C++ extension.  Its use in a
> | > | > function declaration should be mangled differently from any standard
> | > | > C++ construction.  After all, the ABI has provided hook for vendor
> | > | > extension. 
> | > | 
> | > | So you are arguing that this is a bug in g++.
> | > 
> | > Yes.
> | > 
> | > | I don't agree.  To me it seems natural that typeof should simply be
> | > | replaced by the resulting type when doing name mangling.
> | > 
> | > Elsewhere, we seem to refrain from "folding".  Which is what I
> | > referred to in an earlier message as a schizophrenic position.
> | 
> | g++ refrains from folding in expressions which appear as template
> | arguments.  I don't know whether that is right or wrong.
> 
> Yes. Consider but the following case
> 
>    struct foo {
>      typedef int (*bar)();
> 
>      operator bar();
> 
>      template<class T>
>        operator typeof(T (*)());     
>    }; 
> 
> if you use typeof to represent int (*)() in the demangled symbol, do
> you offer a way to distinguish it from the template instantiation with
> T = int (which is a  different function)?

Currently, an instantiation of the latter for T = double looks like:
  foo::operator double (*)()<double>()

For int it would be:
  foo::operator int (*)()<int>()

which is different from
  foo::operator int (*)()()


With Ian's suggestion they would be, I believe:
  foo::operator typeof(double (*)())<double>()
  foo::operator typeof(int (*)())<int>()
  foo::operator typeof(int (*)())()

How useful that difference is, I'm not sure.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer