On Monday, 10 July 2017 at 21:30:44 UTC, Walter Bright wrote:
You can't use RTTI or Exceptions, for example. Those generate
bloat even if they are not used - a compiler switch is typical
to disable them. It's not true that C++ is "pay only for what
you use".
If the C++ usage is "C with member functions", then yes, it'll
work and be useful.
I use C++ for microcontrollers all the time and I prefer to use
exceptions and RTTI for most of my applications. There is a small
amount of bloat when using RTTI and exceptions, but the linker is
able to strip a large amount of it out, so the cost is minimal
and opt-in. I don't see why D couldn't do the same; it just
needs to generate code in a way that allows the linker to
identify dead code.
The only binary size problems I've encountered using C++ is using
iostream and formatted IO. Those seem to generate the most
bloat. But if you avoid iostream and use a C library designed
for microcontrollers (e.g. newlib) it's not a problem. It appear
the bloat mostly comes from the standard library, not the
language.
A recent pull request to GDC
(https://github.com/D-Programming-GDC/GDC/pull/505#event-1141470083) removed much of the TypeInfo bloat that was generated when using classes, which has reignited some interest in using D for microcontrollers. Perhaps there's something in that pull request for other compiler developers to learn from.
Mike
