Precompiling and FunctionWrappers lead to extra runtime allocations about julia

[kimikage]

Just FYI, this problem is reproduced by using precompile(test_precomp, (Int,)) directly without PrecompileTools.

Also, for i in 1:N is necessary to ensure that the allocation occurs with each call, but is not necessary to reproduce the problem itself.

[kimikage]

We now have PkgCacheInspector.jl. However, I could not find the cause.

Edit:
SnoopCompile.@snoopi_deep also helps to understand what is happening.

[kimikage]

Despite the use of function pointers, this problem does not occur in the following simple case.

function test_precomp()
    ptr = @cfunction(cos, Float64, (Float64,))
    ccall(ptr, Float64, (Float64,), 0.0)
end

Edit:
So, the generated function do_call() might be relevant.
https://github.com/yuyichao/FunctionWrappers.jl/blob/ad1cea6fd36a7e72c2755efacd4f28b52fbb1f6a/src/FunctionWrappers.jl#L125-L142

Edit2:
There is a change (PR yuyichao/FunctionWrappers.jl#31) in FunctionWrappers#master, but at least this problem still occurs.

[amilsted]

In case it's a clue: I see allocations like this from FunctionWrappers used in precompiled code in a large codebase (the allocations go away if I don't precompile), but only on Apple Silicon (unlike the minimal case above). For some reason, the problem goes away on x86. Perhaps related to yuyichao/FunctionWrappers.jl#30?