RFC: Pay-as-you-go, Portable D Runtime for Microcontrollers (and maybe more)

[Johannes Pfau via Digitalmars-d]

Am Wed, 06 May 2015 02:44:53 +0000
schrieb "Mike" <none at none.com>:

> On Tuesday, 5 May 2015 at 17:27:05 UTC, Johannes Pfau wrote:
> > Am Tue, 05 May 2015 08:41:13 -0700
> > schrieb Dan Olson <zans.is.for.cans at yahoo.com>:
> >
> >> Iain Buclaw via Digitalmars-d <digitalmars-d at puremagic.com> 
> >> writes:
> >> 
> >> > If the cost is too much (ie: there is no heap), then we 
> >> > should be
> >> > able to stop emutls from kicking in by preventing the D 
> >> > frontend
> >> > from returning true on isThreadLocal calls.
> >> 
> >> Iain, I think something like this would be good in GDC.  Makes 
> >> it so
> >> much easier to compile for no thread environments.
> >
> > I'm not really sure about this. It's trivial to implement but it
> > generates a semantic difference which harms code portability 
> > (e.g. if
> > you have code where you want a global variable, don't mark it as
> > __gshared and then move to an environment with threads).
> 
> I'm coming around and feeling inclined to agree with this.  One 
> of the things I want to avoid is creatIng an embedded dialect of 
> the D.  I hope D for microcontrollers, kernels and such looks 
> very much like the idiomatic D in the application programming 
> domain.
> 
> What I would like to see, however, is a friendly compiler error 
> like "This platform does not support thread-local storage.  
> Please decorate your global variables with __gshared." rather 
> than "undefined reference '_d_get_address'" from the linker.
> 
> 
> Mike

That's easy:
https://github.com/D-Programming-microD/GDC/commit/d5677e03f40f4eb548e520728c5071a0b4445d24

(Well, the error message could be a little bit friendlier ;-)