[Bug c++/101010] New: Feature request: add builtins to provide mangled symbols, optionally with a prefix

["hedayat.fwd at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101010

            Bug ID: 101010
           Summary: Feature request: add builtins to provide mangled
                    symbols, optionally with a prefix
           Product: gcc
           Version: 11.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hedayat.fwd at gmail dot com
  Target Milestone: ---

Currently, there is no method to generate mangled symbol as an string or as a
symbol. 

A mangled symbol as string is useful in many cases for GCC itself, e.g. to use
with alias or ifunc attributes. Currently, you should find the mangled name
yourself and use it there, which is both inconvenient and also might change in
future (or it might be even different for example when compiled with mingw). 

Having a mangled symbol with a prefix (not as a string), is useful when using
the '--wrap' option to ld, to generate __real_SYMBOL and __wrap_SYMBOLs.
Actually, I'm more interested in this one, but found that the former one
(mangled name as string) is also useful. 

Sample intended usage:
void __builtin_mangled_symbol(__wrap_, &MyClass::member)(MyClass *mc_this, int
a)
{
   if (call_real)
       __builtin_mangled_symbol(__real_, &MyClass::member)(mc_this, a);
   else
   {...}
}