GC incurs some overhead. It’d be nice if we don’t have to GC everything. In some cases, we can detect exactly when the memory needs to be freed at compile time. If so, would it be a good idea? Julia is a language that wants to have a cake and eat it too.

we already do this for everything except arrays, although the analysis isn’t interprocederal so it can miss some “obvious” cases

I don’t think we do? We do SROA, i.e. scalar-replacement-of-aggregates, and the scalar replacement lives in registers and maybe spills to the stack. Afaiu we never do stack-alloc, where we know that the lifetime is bounded by the stackframe and we allocate a fully formed object on the stack (pleas…

See the example I gave here: [image] Eager finalization and smart pointers Internals This simplified example looks promising. julia> n::Int = 0 0 julia> const safe_free = Base.@assume_effects :nothrow :notaskstate x->(global n += 1;Libc.free(x.ptr)) #3 (generic function …

[image] foobar_lv2: Afaiu we never do stack-alloc, where we know that the lifetime is bounded by the stackframe and we allocate a fully formed object on the stack (please correct me if if I’m wrong or this changed!). We have a pass llvm-alloc-opt that moves object from the heap to the stack. …

Borrow checker with GC fallback?

Internals & Design

mkitti March 19, 2024, 2:20pm 4

See the example I gave here:

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Borrow checker with GC fallback?

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