Re: [9front] Nim lang, C alignment support

[Emery Hemingway <ehmry@posteo.net>]

Hello Jin,

On Saturday 7 August 2021 00:25:58 CEST, Xiao-Yong Jin wrote:
> What exactly happens when the executables run?  Do you have the Nim
> compiler bootstrapped on 9front?  Or do you just try to compile the
> C code generated from other host OS?

Nim executables seem to run until memory starts being freed. It's a
double-free panic in pool.c or else I get a stack-trace leading to
gc.nim. Simple programs are usable, I have the compiler bootstrapped
enough to print it's version and usage message to stdout, but with any
load it will dealloc and break.

> Did you try to turn off all the extra checks and just use malloc, like,
>
> 	-d:danger --panics:on --gc:arc -d:useMalloc

I've tried these and --gc:orc but things seem to break in the same way.

> If I understand correctly, the only place that relies on the alignment
> is Nim's allocator, for whatever reason, and it did not appear until
> late 2019 as an optimization and safety guarantees for dynamic libraries.
> If you can figure out where it actually "goes to shit", you might be
> able to avoid using alignment at all.

I think you are right, it may be possible to disable some optimizations,
I'll see what I can do. If anyone is curious I've documented the
bootstrapping process.

https://github.com/ehmry/Nim/tree/plan9#readme


Thanks for the encouragement,
Emery