Unresolved calls when compiling with juliac and --trim

[Yuan-Ru-Lin]

The code snippet below (from #308) can't be compiled by juliac with --trim anymore

using FFTW

Base.@ccallable function main()::Cint
    v = fft([0; 1; 2; 1])
    for elem in v
        println(Core.stdout, elem)
    end
    return 0
end

julialauncher +1.12 --project=. --startup-file=no $CFSUSER/.juliaup/juliaup/julia-1.12.0-rc1+0.x64.linux.gnu/share/julia/juliac/juliac.jl --output-exe a.out --compile-ccallable --experimental --trim script2.jl
Verifier error #1: unresolved call from statement FFTW.unsafe_destroy_plan(φ ()::FFTW.FFTWPlan)::Any
Stacktrace:
 [1] foreach(f::typeof(FFTW.unsafe_destroy_plan), itr::Vector{FFTW.FFTWPlan})
   @ Base abstractarray.jl:3188 [inlined]
 [2] destroy_deferred()
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:339
 [3] (FFTW.cFFTWPlan{ComplexF64, -1, false, 1})(X::Vector{ComplexF64}, Y::FFTW.FakeArray{ComplexF64, 1}, region::UnitRange{Int64}, flags::UInt32, timelimit::Float64)
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/FFTW.jl:74
 [4] plan_fft(X::Vector{ComplexF64}, region::UnitRange{Int64}; flags::UInt32, timelimit::Float64, num_threads::Nothing)
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:787 [inlined]
 [5] plan_fft(X::Vector{ComplexF64}, region::UnitRange{Int64})
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:777 [inlined]
 [6] fft(x::Vector{ComplexF64}, region::UnitRange{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:67 [inlined]
 [7] fft(x::Vector{Int64}, region::UnitRange{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:214
 [8] fft(x::Vector{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:66 [inlined]
 [9] main()
   @ Main /global/u2/y/yuanru/trimtest/script2.jl:4

Verifier error #2: unresolved call from statement FFTW.unsafe_destroy_plan(φ ()::FFTW.FFTWPlan)::Any
Stacktrace:
 [1] foreach(f::typeof(FFTW.unsafe_destroy_plan), itr::Vector{FFTW.FFTWPlan})
   @ Base abstractarray.jl:3188 [inlined]
 [2] destroy_deferred()
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:339
 [3] (FFTW.cFFTWPlan{ComplexF64, -1, false, 1})(X::Vector{ComplexF64}, Y::FFTW.FakeArray{ComplexF64, 1}, region::UnitRange{Int64}, flags::UInt32, timelimit::Float64)
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/FFTW.jl:74
 [4] plan_fft(X::Vector{ComplexF64}, region::UnitRange{Int64}; flags::UInt32, timelimit::Float64, num_threads::Nothing)
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:787 [inlined]
 [5] plan_fft(X::Vector{ComplexF64}, region::UnitRange{Int64})
   @ FFTW /pscratch/sd/y/yuanru/.julia/packages/FFTW/r6EbH/src/fft.jl:777 [inlined]
 [6] fft(x::Vector{ComplexF64}, region::UnitRange{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:67 [inlined]
 [7] fft(x::Vector{Int64}, region::UnitRange{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:214
 [8] fft(x::Vector{Int64})
   @ AbstractFFTs /pscratch/sd/y/yuanru/.julia/packages/AbstractFFTs/4iQz5/src/definitions.jl:66 [inlined]
 [9] main()
   @ Main /global/u2/y/yuanru/trimtest/script2.jl:4

Trim verify finished with 2 errors, 0 warnings.

Failed to compile script2.jl

Here's result of versioninfo()

Julia Version 1.12.0-rc1
Commit 228edd6610b (2025-07-12 20:11 UTC)
Build Info:
  Official https://julialang.org release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 256 × AMD EPYC 7713 64-Core Processor
  WORD_SIZE: 64
  LLVM: libLLVM-18.1.7 (ORCJIT, znver3)
  GC: Built with stock GC
Threads: 1 default, 1 interactive, 1 GC (on 256 virtual cores)
Environment:
  JULIA_PROJECT = @work
  JULIA_DEPOT_PATH = /pscratch/sd/y/yuanru/.julia

[timholy]

At this point is would be safer (and frankly shorter) to rewrite

FFTW.jl/src/fft.jl

Lines 338 to 343 in dbcb5d2

	@static if Base.VERSION >= v"1.9"
	@inline foreach(unsafe_destroy_plan, deferred_destroy_plans)
	else
	# call-site @inline isn't supported on old versions of Julia
	foreach(unsafe_destroy_plan, deferred_destroy_plans)
	end

to use a loop rather than foreach. Want to give it a try, @Yuan-Ru-Lin?

[Yuan-Ru-Lin]

Changing the code block to

for plan in deferred_destroy_plans
    unsafe_destroy_plan(plan)
end

doesn't work.

I added a type hint to the result of unsafe_destroy_plan because it's a ccall whose result is of type Cvoid; that is,

for plan in deferred_destroy_plans
    unsafe_destroy_plan(plan)::Nothing
end

but juliac still think there's a resolved call

Verifier error #1: unresolved call from statement FFTW.unsafe_destroy_plan(φ ()::FFTW.FFTWPlan)::Nothing

[timholy]

OK. I guess the problem is

julia> Base.unwrap_unionall(FFTW.FFTWPlan)
FFTW.FFTWPlan{T<:Union{Float32, Float64, ComplexF64, ComplexF32}, K, inplace}

and something must have changed to make juliac not make it's way through despite the @nospecialized in unsafe_destroy_plan.

I'd recommend filing this as a Julia issue.

[Moelf]

is that just union splitting giving up?

[timholy]

The K and inplace are open-ended, so there's no union to split