trimming: no way to `ccall` into a dynamically-computed library name

[topolarity]

Once #57706 is fixed, there will be no way to compute a library string dynamically for a ccall because

1. ccall forbids referring to local variables:

julia> foo() = (b = bar(); ccall((:test, b), Cvoid, ()))
ERROR: syntax: ccall function name and library expression cannot reference local variables

2. inference / optimizer never inlines / resolves the library function for a ccall:

julia> bar() = string(rand(Int))
julia> foo() = ccall((:test, bar()), Cvoid, ())
julia> code_typed(foo, ())
1-element Vector{Any}:
 CodeInfo(
1 ─     $(Expr(:foreigncall, :(Core.tuple(:test, Main.bar())), Nothing, svec(), 0, :(:ccall)))::Nothing
└──     return nothing
) => Nothing

Notice that the call to Main.bar() is embedded as a sub-expression in Expr(:foreigncall) and is never explored by inference / optimizer.

[topolarity]

fwiw, you can workaround this similar to JLL's by storing to a global and explicitly calling a setup function in, e.g., a OncePerProcess initializer just before you do the ccall, but it's pretty awkward

[vchuravy]

Notice that the call to Main.bar() is embedded as a sub-expression in Expr(:foreigncall) and is never explored by inference / optimizer.

We should be able to do that. In

julia/Compiler/src/abstractinterpretation.jl

Lines 3448 to 3449 in d369c10

	function abstract_eval_foreigncall(interp::AbstractInterpreter, e::Expr, sstate::StatementState, sv::AbsIntState)
	mi = frame_instance(sv)

we could look through the tuple and run inference over it? Perhaps even concrete eval it?