expected return statement, got JuliaInterpreter.SSAValue(2)

[fredrikekre]

With the following (minified) package

module ReviseBug

using Tensors

struct A
    x::Tensor{2,3,Float64,9}
end

function foo()
    x = 1.0 * one(Tensor{2,3,Float64,9}) # removing the multiplication makes things work
    return A(x)
end

const a = foo()

end # module

I get the following when trying to revise the module:

julia> using Revise, ReviseBug

shell> touch src/ReviseBug.jl

julia> 1+1
┌ Warning: omitting call expression (ReviseBug.foo)() in ("none", 0)
└ @ Revise ~/.julia/packages/Revise/UtBAC/src/lowered.jl:169
┌ Error: evaluation error
│   mod = ReviseBug
│   ex = :(const a = foo())
│   exception =
│    expected return statement, got a = JuliaInterpreter.SSAValue(2)
│    Stacktrace:
│     [1] error(::String, ::Expr) at ./error.jl:42
│     [2] get_return(::JuliaInterpreter.Frame) at /home/fredrik/.julia/packages/JuliaInterpreter/6LimI/src/interpret.jl:598
│     [3] #methods_by_execution!#14(::Bool, ::Bool, ::Function, ::Any, ::Revise.CodeTrackingMethodInfo, ::Dict{Module,Array{Expr,1}}, ::JuliaInterpreter.Frame) at /home/fredrik/.julia/packages/Revise/UtBAC/src/lowered.jl:185
│     [4] #methods_by_execution! at ./none:0 [inlined]
│     [5] #methods_by_execution!#9(::Base.Iterators.Pairs{Symbol,Bool,Tuple{Symbol},NamedTuple{(:define,),Tuple{Bool}}}, ::Function, ::Any, ::Revise.CodeTrackingMethodInfo, ::Dict{Module,Array{Expr,1}}, ::Module, ::Expr) at /home/fredrik/.julia/packages/Revise/UtBAC/src/lowered.jl:49
│     [6] #methods_by_execution! at ./none:0 [inlined]
│     [7] #eval_with_signatures#59(::Bool, ::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Function, ::Module, ::Expr) at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:344
│     [8] #eval_with_signatures at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:0 [inlined]
│     [9] #instantiate_sigs!#60(::Bool, ::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Function, ::OrderedCollections.OrderedDict{Module,OrderedCollections.OrderedDict{Revise.RelocatableExpr,Union{Nothing, Array{Any,1}}}}) at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:352
│     [10] instantiate_sigs! at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:349 [inlined]
│     [11] maybe_parse_from_cache!(::Revise.PkgData, ::String) at /home/fredrik/.julia/packages/Revise/UtBAC/src/pkgs.jl:224
│     [12] handle_deletions at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:473 [inlined]
│     [13] revise() at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:526
│     [14] revise at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:551 [inlined]
│     [15] run_backend(::REPL.REPLBackend) at /home/fredrik/.julia/packages/Revise/UtBAC/src/Revise.jl:941
│     [16] (::getfield(Revise, Symbol("##74#76")){REPL.REPLBackend})() at ./task.jl:259
└ @ Revise ~/.julia/packages/Revise/UtBAC/src/lowered.jl:52
2

Maybe there is something funky going on with @pure-usage in Tensors.jl? As noted, removing the multiplication solves the problem.

[fredrikekre]

$ jlpkg st -m Revise
Project ReviseBug v0.1.0
    Status `~/dev/ReviseBug/Manifest.toml`
  [da1fd8a2] CodeTracking v0.5.7
  [aa1ae85d] JuliaInterpreter v0.5.1
  [6f1432cf] LoweredCodeUtils v0.3.4
  [bac558e1] OrderedCollections v1.1.0
  [295af30f] Revise v2.1.4
  [8ba89e20] Distributed 
  [7b1f6079] FileWatching 
  [76f85450] LibGit2 
  [44cfe95a] Pkg 
  [3fa0cd96] REPL 
  [cf7118a7] UUIDs 
  [4ec0a83e] Unicode

[timholy]

What Julia version? If recent, please try master branch of JuliaInterpreter, may have been fixed by #286

[fredrikekre]

1.1.1, but also happens on julia master (JuliaLang/julia@efd794e), also happens with JuliaInterpreter master (04d1fb5).

[timholy]

Problematic call is here, it's a this intrinsic must be compiled to be called error. We're failing to detect an llvmcall emitted by a @generated function. Help getting a Revise-independent (pure @interpret) MWE would be appreciated.

[fredrikekre]

Ah okay. Yea, I had problems in the early days of the new JuliaInterpreter with SIMD.jl, but forgot about it. Here is an example, still with Tensors but I can probably work out a pure julia example later tonight:

julia> using JuliaInterpreter, Tensors

julia> f() = 1.0 * one(Tensor{2,3})
f (generic function with 1 method)

julia> @interpret f()
ERROR: this intrinsic must be compiled to be called

[timholy]

That's probably good enough, we can make Tensors a test dependency. Thanks!

[KristofferC]

So, dup of #112?

[fredrikekre]

I just got this error again with [email protected] when running the original code.

[timholy]

Drat. Forgot about this until today. I poked at it, and it's a world-age issue (it should work if you edit it a second time). The issue is that our tests run at top-level and hence the world age can update, whereas with Revise it's run from inside a function.

I only see one option: when we define compiled handlers for llvmcall (and probably ccall), we may need to do something evil: extract the method tables and set the world age to that of the current running task. Thoughts, @KristofferC? (I know how to do that and will implement it if appropriate, I'm just wonder if it's something we can countenance.)

[KristofferC]

I don't fully grok methods_by_execution! but is there no equivalent of invokelatest we could use here?

If you feel messing with world ages is the best we can do then let's go with that.

[timholy]

Good question. I was worried we'd have to add it lots of places, but you prompted me to check again. Turns out we can fix it by making this line invokelatest. I think that's a pretty rare path, and the benchmarks don't seem different, so seems like perhaps worth trying?