Re: [Sbcl-devel] [Sbcl-commits] master: x86-64, struct-by-value: correctly pass small structs on the stack

[Jesse B. <jes...@pr...>]

I have failing test cases for both of those. I'm working on the callback overwrites right now.

> On Apr 25, 2026, at 11:14 AM, Stas Boukarev <sta...@gm...> wrote:
> 
> Another issue, nested struts are not flattened correctly:
> SB-VM> (classify-struct (parse-alien-type '(struct nil (inner (struct
> nil (d double) (i int)))) nil))
> #S(SB-ALIEN::STRUCT-CLASSIFICATION :REGISTER-SLOTS (:INTEGER :INTEGER)
> :SIZE 16 :ALIGNMENT 64 :MEMORY-P NIL)
> SB-VM> (classify-struct (parse-alien-type '(struct nil (d double) (i int)) nil))
> #S(SB-ALIEN::STRUCT-CLASSIFICATION :REGISTER-SLOTS (:DOUBLE :INTEGER)
> :SIZE 16 :ALIGNMENT 64 :MEMORY-P NIL)
> 
> And callbacks seem to suffer from over-reads/writes.
> 
> On Fri, Apr 24, 2026 at 12:40 AM Jesse Bouwman
> <jes...@pr...> wrote:
>> 
>> Stas, if you want to send me a list of findings and test gaps, I will put time into closing them out -- just raw notes or LLM findings are enough.
>> 
>> Jesse
>> 
>>> On Apr 23, 2026, at 2:25 PM, Stas Boukarev <sta...@gm...> wrote:
>>> 
>>> The struct-by-value issues keep coming and coming, I'm already tired
>>> of fixing them, have no strength to add proper tests.
>>> And it also needs to test for over-reading input structures, I have
>>> some scaffolding from the time of writing simd routines which mmaps
>>> data at the edges of a protected region.
>>> 
>>> On Thu, Apr 23, 2026 at 11:17 PM Christophe Rhodes <cs...@ca...> wrote:
>>>> 
>>>> Stas Boukarev <sta...@gm...> writes:
>>>> 
>>>>> I just send c-call.lisp to various free LLMs and say "find bugs here".
>>>>> And also make them generate test cases.
>>>>> I didn't include any specific test because they won't find new
>>>>> problems.
>>>> 
>>>> Sure, but they'll help the day someone wants to make struct-by-value
>>>> work on platforms that don't support it yet.  (Maybe in this grand
>>>> future that's less necessary because we'll just send riscv's c-call to
>>>> some LLM and say "now implement the struct-by-value ABI please".)
>>>> 
>>>>> A test that performs an exhaustive combination of different foreign
>>>>> types is needed.
>>>>> But I'm not eager to make that yet.
>>>> 
>>>> ... that would work too, sure.  I can be patient.
>>>> 
>>>> Thanks,
>>>> 
>>>> Christophe
>>> 
>>> 
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>> 
>>