RFA: Please review the new C++ demangler patch

[Zack Weinberg]

"H. J. Lu" <hjl@lucon.org> writes:

>> Having the C++ compiler around should not be a problem.  I'm worried
>> about the requirement for libstdc++, which (as discussed upthread)
>> produces nasty circular build dependencies that I am not convinced
>> have been adequately addressed.
>
> The circular build dependency is only a concern for the target
> demangler library. There are
>
> configure-target-demangler: maybe-all-target-libstdc++-v3
> all-target-demangler: configure-target-demangler
>
> in Makefile.tpl. That is we build the target demangler after libstdc++
> is available.

So you want to have two copies of the demangler?  Or how do you
propose to get the demangler into libstdc++?

> It is only useful if the C++ compiler for build doesn't have a
> working <vector>. The demangler configure checks if the C++ compiler
> can compile the demangler and link the resulting demangler library
> with the C compiler before enabling it. It doesn't handle the case
> where <vector> exists, but doesn't work right. But I don't think it
> should be a factor here. I don't see why any gcc developers should
> spend time to help broken C++ compilers.

The case of concern is where the "C++ compiler for build" does not
exist; i.e. bootstrapping from just a C compiler.

zw