MWE of char crash

[GunnarFarneback]

This reproduces the crash in the char tests.

using JuliaInterpreter
ex = quote
    a = ['0']
    b = ['a']
    c = [a; b]
end
frame = JuliaInterpreter.prepare_toplevel(Main, ex)
JuliaInterpreter.finish_and_return!(JuliaStackFrame[], frame, true)

with the result

Unreachable reached at 0x7f9c2cce8ab4

signal (4): Illegal instruction
[...]

[KristofferC]

Seems to work locally on Windows on both 1.1 and master.

julia> JuliaInterpreter.finish_and_return!(JuliaStackFrame[], frame, true)
 2-element Array{Char,1}:
 '0'
 'a'

> versioninfo()
Julia Version 1.1.0
Commit 80516ca202 (2019-01-21 21:24 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)

[GunnarFarneback]

julia> versioninfo()
Julia Version 1.2.0-DEV.320
Commit 38d6247 (2019-02-13 21:23 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)
Environment:
  IPYTHON_JL_SETUP_PYJULIA = no

[timholy]

I can replicate with both 1.1 and master.

julia> versioninfo()
Julia Version 1.1.1-pre.0
Commit a84cf6f56c* (2019-01-22 04:33 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)
Environment:
  JULIAFUNCDIR = /home/tim/juliafunc
  JULIA_CPU_THREADS = 2

(My master is one commit later than @GunnarFarneback)

[pfitzseb]

This is the line that fails, I think. Maybe something going wrong with the @_gc_preserve_begin?

[timholy]

Here's a repro that doesn't even use JuliaInterpreter:

julia> a, b = ['0'], ['a'];

julia> eltype(a)
Char

julia> arr = Vector{Char}(undef, 2)
2-element Array{Char,1}:
 '\0'              
 '\x00\x00\x7f\x89'

julia> ptr = pointer(arr)
Ptr{Char} @0x00007f893d190cb0

julia> elsz = sizeof(Char)
4

julia> na = length(a)
1

julia> nba = na * elsz
4

julia> ccall(:memcpy, Ptr{Cvoid}, (Ptr{Cvoid}, Ptr{Cvoid}, UInt), ptr, a, nba)
Unreachable reached at 0x7f893412a95e

I'll file this as a Julia issue.

[timholy]

JuliaLang/julia#31073

[GunnarFarneback]

The arrayops crash looks very similar to this one. They may well have the same cause.

[timholy]

If we do #13 (comment), it might fix this issue too. If not, we need to develop a workaround for this. Even if the bug is fixed in Julia itself, I doubt we want to force people to run a 3-day old master in order to use JuliaInterpreter.