Build failure on ARM32 (Raspberry Pi 4B) plus proposed fix

[wiremoons]

Bug found while compiling a test app on a Raspberry Pi 4B. The same code had previously compiled ok under Ubuntu in an x86 machine.

Bug is caused by additional source code that had been added to fix a problem with compiling for Windows 32bit, based on the comment left at the point of breakage. The comment was helpful however in locating the bug :)

I have provided a pull request with a proposed fix that works ok once applied.

Just for completeness:

The following Raspberry Pi operating system and kernel version is being used

Linux pi4mobi 4.19.79-v7l+ #1273 SMP Fri Oct 11 18:23:45 BST 2019 armv7l GNU/Linux

Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 10 (buster)
Release:        10
Codename:       buster

The Julia version is the pre-complied version from Julia downloads, as follows:

Julia Version 1.3.0
Commit 46ce4d7933 (2019-11-26 06:09 UTC)
Platform Info:
  OS: Linux (arm-linux-gnueabihf)
  CPU: ARMv7 Processor rev 3 (v7l)
  WORD_SIZE: 32
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, cortex-a72)

Package versions being used are:

(v1.3) pkg> status
    Status `~/.julia/environments/v1.3/Project.toml`
  [c7e460c6] ArgParse v0.6.2
  [9b87118b] PackageCompiler v0.6.5

The source code of the test app is:

# hello_binary.jl
#

function SayHello()
    println("Hello World!")
end

# Main : required PackageComplier boilerplate startup function
Base.@ccallable function julia_main(ARGS::Vector{String})::Cint
    SayHello()
    return 0
end

The build command is below, noting that juliac is a bash alias as: alias juliac='$HOME/.julia/packages/PackageCompiler/4yNnV/juliac.jl'

juliac ./hello_binary.jl -tavern hello_binary

The build output including the error and failure message is:

Julia program file:
  "/home/simon/projects/code/julia/hello_binary/hello_binary.jl"
C program file:
  "/home/simon/.julia/packages/PackageCompiler/4yNnV/examples/program.c"
Build directory:
  "/home/simon/projects/code/julia/hello_binary/builddir"
Make build directory
Build static library "hello_binary.a":
  atexit_hook_copy = copy(Base.atexit_hooks) # make backup
# clean state so that any package we use can carelessly call atexit
empty!(Base.atexit_hooks)
Base.__init__()
Sys.__init__() #fix /~https://github.com/JuliaLang/julia/issues/30479
using REPL
Base.REPL_MODULE_REF[] = REPL
Mod = @eval module $(gensym("anon_module")) end
# Include into anonymous module to not polute namespace
Mod.include("/home/simon/projects/code/julia/hello_binary/hello_binary.jl")
Base._atexit() # run all exit hooks we registered during precompile
empty!(Base.atexit_hooks) # don't serialize the exit hooks we run + added
# atexit_hook_copy should be empty, but who knows what base will do in the future
append!(Base.atexit_hooks, atexit_hook_copy)

Build shared library "hello_binary.so":
  `cc -shared '-DJULIAC_PROGRAM_LIBNAME="hello_binary.so"' -o hello_binary.so -Wl,--whole-archive hello_binary.a -Wl,--no-whole-archive -std=gnu99 -I/home/simon/.julia-dev/include/julia -DJULIA_ENABLE_THREADING=1 -fPIC -L/home/simon/.julia-dev/lib -Wl,--export-dynamic -Wl,-rpath,/home/simon/.julia-dev/lib -Wl,-rpath,/home/simon/.julia-dev/lib/julia -ljulia -mbe32 -O3`
Build executable "hello_binary":
  `cc '-DJULIAC_PROGRAM_LIBNAME="hello_binary.so"' -o hello_binary /home/simon/.julia/packages/PackageCompiler/4yNnV/examples/program.c hello_binary.so -std=gnu99 -I/home/simon/.julia-dev/include/julia -DJULIA_ENABLE_THREADING=1 -fPIC -L/home/simon/.julia-dev/lib -Wl,--export-dynamic -Wl,-rpath,/home/simon/.julia-dev/lib -Wl,-rpath,/home/simon/.julia-dev/lib/julia -ljulia -mbe32 -O3 '-Wl,-rpath,$ORIGIN' -march=pentium4`
cc: error: unrecognized -march target: pentium4   
cc: note: valid arguments are: armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5t armv5e armv5te armv5tej armv6 armv6j armv6k armv6z armv6kz armv6zk armv6t2 armv6-m armv6s-m armv7 armv7-a armv7ve armv7-r armv7-m armv7e-m armv8-a armv8.1-a armv8.2-a armv8.3-a armv8.4-a armv8-m.base armv8-m.main armv8-r iwmmxt iwmmxt2 native
cc: error: missing argument to ‘-march=’
ERROR: LoadError: failed process: Process(`cc '-DJULIAC_PROGRAM_LIBNAME="hello_binary.so"' -o hello_binary /home/simon/.julia/packages/PackageCompiler/4yNnV/examples/program.c hello_binary.so -std=gnu99 -I/home/simon/.julia-dev/include/julia -DJULIA_ENABLE_THREADING=1 -fPIC -L/home/simon/.julia-dev/lib -Wl,--export-dynamic -Wl,-rpath,/home/simon/.julia-dev/lib -Wl,-rpath,/home/simon/.julia-dev/lib/julia -ljulia -mbe32 -O3 '-Wl,-rpath,$ORIGIN' -march=pentium4`, ProcessExited(1)) [1]

Stacktrace:
 [1] pipeline_error at ./process.jl:525 [inlined] 
 [2] #run#565(::Bool, ::typeof(run), ::Cmd) at ./process.jl:440
 [3] run(::Cmd) at ./process.jl:438
 [4] (::PackageCompiler.var"#19#20")() at /home/simon/.julia/packages/PackageCompiler/4yNnV/src/static_julia.jl:328
 [5] cd(::PackageCompiler.var"#19#20", ::String) at ./file.jl:104
 [6] build_exec(::String, ::String, ::String, ::String, ::Bool, ::String, ::String, ::Cmd, ::Array{String,1}) at /home/simon/.julia/packages/PackageCompiler/4yNnV/src/static_julia.jl:327
 [7] #static_julia#5(::Nothing, ::Bool, ::Bool, ::Nothing, ::String, ::Nothing, ::Bool, ::Bool, ::Bool, ::Bool, ::Bool, ::Bool, ::Bool, ::Bool, ::Nothing, ::Bool, ::Bool, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Nothing, ::Array{String,1}, ::typeof(static_julia), ::String) at /home/simon/.julia/packages/PackageCompiler/4yNnV/src/static_julia.jl:171
 [8] (::PackageCompiler.var"#kw##static_julia")(::NamedTuple{(:verbose, :rmtemp, :cc_flags, :outname, :autodeps, :executable, :release),Tuple{Bool,Bool,Array{String,1},String,Bool,Bool,Bool}}, ::typeof(static_julia), ::String) at ./none:0
 [9] julia_main(::Array{String,1}) at /home/simon/.julia/packages/PackageCompiler/4yNnV/juliac.jl:182
 [10] top-level scope at /home/simon/.julia/packages/PackageCompiler/4yNnV/juliac.jl:188
 [11] include at ./boot.jl:328 [inlined]
 [12] include_relative(::Module, ::String) at ./loading.jl:1105
 [13] include(::Module, ::String) at ./Base.jl:31 
 [14] exec_options(::Base.JLOptions) at ./client.jl:287
 [15] _start() at ./client.jl:460
in expression starting at /home/simon/.julia/packages/PackageCompiler/4yNnV/juliac.jl:187