Tria - the Elixir optimizer

[hst337]

@josevalim

What we could do in Elixir itself is to keep a list of the functions in its standard library that are pure. Erlang also keeps a similar list for its standard library and inlines those. WDYT?

Yeah, I am using Erlang’s list, but unfortunately, :erl_bifs covers only :erlang module. I didn’t know about list of pure Elixir functions, I’ll grep the Elixir sources then, thanks for the tip!

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@josevalim

We can make this generally applicable but it is worth keeping in mind that each inlined modules becomes a compile-time dependency, and enlarging the compile time graphic can have huge impacts on performance

I didn’t quite get what you meant.

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@josevalim

It is also not possible to know if something is pure or not when calling Erlang functions (unless we have an FFI layer where you also explicitly declare those).

Well, it depends on these Erlang functions. If abstract_code for the function can be fetched, it can be analyzed for purity and safety. If the abstract_code is not present, or the function is a NIF/BIF stub, we can ask a user to provide the value for a trait, or just assume the worst (impurity or unsafety)