On Mon, May 31, 2010 at 7:22 AM, Robert Dewar <de...@adacore.com> wrote:
> One interesting issue is whether it is important for gcc to be
> able to be compiled with foreign compilers (other than gcc).
>
> I know that historically this has been an important requirement,
> but I wonder whether it is still relevant.
>
> Gcc is very widespread at this point. Yes, there is the issue
> of completely new targets, but these can be easily handled by
> building cross-compilers.
>
> I suspect that the use of C++ will make the use of foreign
> compilers harder, but I suspect also that it doesn't matter.
I do not think so, and I would not suggest that the use of C++ is an excuse
do ditch the possibility of bootstrapping with anything other than GCC.
As for the subset of C++ to use, yes we need to be conservative. A very
large part of C++98 is well established. Although it would be tempting, I would
recommend against using it as with "C with classes". We should be able to use:
* classes with multiple access protection sections (i.e. public sectionsfor
interface operations, private section for data members that should not be
accessed directly, etc.)
* full single inheritance
* multiple inheritance where appropriate, but NOT virtual inheritance
* namespaces to partition codes. Prefer explicit qualification over
reliance on argument dependent name lookup (except for
operators, of course)
* simple templates -- e.g. containers, simple functions, but avoid creative
uses such as template metaprogramming.
* avoid casts, and dynamic_cast should be kept to the minimum -- use of
virtual functions should be preferred (as we currently do with hooks).
* trust the reviewers to use the best judgments.
-- Gaby
