Midir crosscompilation not possible

[atoav]

I am not sure if this is a bug or just my own fault, but I can't crosscompile for a raspberry pi when midir is a dependency (it works just fine if I comment it out in Cargo.toml).

The problem seems to happen at the linker stage (warning, really long!):

error: linking with `arm-linux-gnueabihf-gcc` failed: exit code: 1
  |
  = note: "arm-linux-gnueabihf-gcc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-L" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.25syr1jzb3exvk4y.rcgu.o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.2hfogt1f3dulz1n8.rcgu.o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.2kwzfdj7r6e7gc1x.rcgu.o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.3lwv1peyt9qjersl.rcgu.o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.4z41z2gtkawr4vib.rcgu.o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.8nly3lsfi38ubgi.rcgu.o" "-o" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps/midi_to_trigger-8e6e7ed081b07421.17xjcw3dr7n7ptsr.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/home/d0/Coding/work/midi_to_trigger/target/arm-unknown-linux-gnueabihf/debug/deps" "-L" "/home/d0/Coding/work/midi_to_trigger/target/debug/deps" "-L" "/usr/lib/x86_64-linux-gnu" "-L" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libstd-95f5053e3555b465.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libpanic_unwind-625d9a5dfe06f142.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libhashbrown-4bdaee786b6ecc2f.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/librustc_std_workspace_alloc-4896b2c7440385ff.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libbacktrace-359913043371f425.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libbacktrace_sys-3189fe54f33ba5a6.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/librustc_demangle-278e49f56bc4aa04.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libunwind-932bef4eba16b4ec.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libcfg_if-d2a28b76ca5161ed.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/liblibc-0bb253fb21b3c0c3.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/liballoc-933869c77bd04128.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/librustc_std_workspace_core-9b29881a4cdf4184.rlib" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libcore-a7e5328f57a93d46.rlib" "-Wl,--end-group" "/home/d0/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/arm-unknown-linux-gnueabihf/lib/libcompiler_builtins-ce2041e567e5f109.rlib" "-Wl,-Bdynamic" "-ldl" "-lrt" "-lpthread" "-lgcc_s" "-lc" "-lm" "-lrt" "-lpthread" "-lutil" "-lutil"
  = note: /usr/lib/x86_64-linux-gnu/libdl.so: file not recognized: File format not recognized
          collect2: error: ld returned 1 exit status

I managed to compile the same thing directly on the target hardware, but it takes forever and speeding it up would be really convinient. Any ideas?

[Boddlnagg]

I have no idea what's going on there ... I'm not an expert with linking on Linux. It seems weird to me, though, that the -ldl flag passed to the ARM linker makes the linker try to load /usr/lib/x86_64-linux-gnu/libdl.so (note the x86_64) ...

[atoav]

Sadly I don't have too much experience with linkers myself, so I can't help. But it would be very cool to be able to cross compile midir to ARM targets as this would be a natural match for all kind of midi manipulators, controllers, etc. For example I am currently working on something that converts MIDI notes to modular synth/eurorack gates via GPIO.