Porting D to custom OS

[Denis Feklushkin]

On Saturday, 22 February 2020 at 13:20:40 UTC, IGotD- wrote:
> I'm trying to find information how to port D, especially the D 
> runtime to a proprietary OS.

Here is my "Frankenstein" MCU project: 
https://github.com/denizzzka/d_c_arm_test
Maybe this will help you somehow.

It is forced to use simultaneously: ldc2, clang, gcc, make, 
meson. Currently it uses ARM but also I interested in RISC-V.

It almost works except druntime.

> Will there be a future improvement of this so that OS specific 
> support can be moved to separate files and selected on module 
> level instead?

Hurrah! I come by search with same idea!

I looked into druntime for several days (and never before) and 
now I think that tree of its source code isn't organized properly 
and this stucks porting it to architectures very different from 
well-known Posix.

For example, look:
https://github.com/dlang/druntime/blob/master/src/core/stdc/errno.d
https://github.com/dlang/druntime/blob/master/src/core/stdc/stdio.d

Without moving out of architecture-dependent code into separate 
"subprojects" it is impossible to imagine that this code can be 
ported without significant labor costs.

Also, such a takeaway is necessary because by "architecture" we 
can mean  identical "CPU + OS" bundles but just with different 
definitions ​​of modern types like int_fast16_t and so on - 
thousands of "architectures"! This is actual for MCU.

Moreover, it would be nice to make as much as possible any parts 
of this "backend" optional. Let a compilation error happens if 
there is no some functionality. Then these talks about a certain 
"minimal druntime", which, in fact, provides abilities what 
already gives betterC, will stop.

Perhaps this proposal isn't new, but the search yielded nothing 
except your message.