Binding a single function symbol with [foreign]

Jorn Vernee jbvernee at
Mon Sep 10 14:33:48 UTC 2018

> So, for simple calls like puts, which take a single integer register
> value and returns via a single register value, things *should* work -
> but it seems like it doesn't. Anyway, the current support is, as I
> wrote, mostly Linux and MacOs centric - and we're not planning to do
> Windows tweak in the short term at least. But your experiment suggests
> that we might not be that far off the mark...

I was just reading up on the MS x64 ABI [1], and the main difference 
seems to be that the caller is expected to allocate 32 bytes of 'shadow 
space' on the stack right before the call so that the function can do 
argument register spill into that space (I guess to make it easier to 
forward to cdecl functions?). It doesn't look like the current 
implementation accounts for that (?), so puts is probably corrupting the 
stack values that are there, and it blows up on return.


[1] :

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