Can not cross compile for target aarch64-linux-gnu-gcc due to linking error "error adding symbols: file in wrong format"

[BoolPurist]

What is the problem

I want to cross compile on fedora 37 amd 64 bit for a rasberry pi 4, arm 64 bit.
I can cross compile a hello world program for this target. However as soon as I use this crate in the project, the cross compiling fails with an linking error /aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib: error adding symbols: file in wrong format.

Rust set up

rustc version

rustc 1.65.0 (897e37553 2022-11-02)

rust toolchain

installed toolchains
--------------------

stable-x86_64-unknown-linux-gnu (default)
nightly-x86_64-unknown-linux-gnu

installed targets for active toolchain
--------------------------------------

aarch64-unknown-linux-gnu
armv7-unknown-linux-gnueabihf
x86_64-unknown-linux-gnu

active toolchain
----------------

stable-x86_64-unknown-linux-gnu (default)
rustc 1.65.0 (897e37553 2022-11-02)

How to reproduce it

I cross compile via this command

cargo build --target aarch64-unknown-linux-gnu

For this code

use rpi_led_matrix::{LedColor, LedMatrix};

fn main() {
    let matrix = LedMatrix::new(None, None).expect("Could not create led matrix from options");
    let mut canvas = matrix.offscreen_canvas();
    for red in 0..255 {
        for green in 0..255 {
            for blue in 0..255 {
                canvas.fill(&LedColor { red, green, blue });
                canvas = matrix.swap(canvas);
            }
        }
    }
}

Error output

   Compiling led_matrix v0.1.0 (/home/nicegraphi/Code/rust/LedMatrixInf)
error: linking with `aarch64-linux-gnu-gcc` failed: exit status: 1
  |
  = note: "aarch64-linux-gnu-gcc" "/tmp/rustcXPqgt8/symbols.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.1826tw3csssunte5.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.2ff05qk8jmu9l08h.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.2u3fw9wgfj54e3eh.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.2u78656zh9kh0r5w.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.2vguhu8z0ndppkh7.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.341jrsfsc8rb8drs.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.3dl0odp5weyipdgc.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.3oo094vgey4n82jv.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.3za1b1ck4wef2062.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.4xmof5bev8sq57xl.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.99jk30mbiggor1t.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.gmm87eakcji2w4g.rcgu.o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520.42tvuzb7j9lbf48y.rcgu.o" "-Wl,--as-needed" "-L" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps" "-L" "/home/nicegraphi/Code/rust/LedMatrixInf/target/debug/deps" "-L" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/build/rpi-led-matrix-sys-51f97f517a6f991b/out/cpp-library/lib" "-L" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix-f41353ffb9e61f71.rlib" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/libembedded_graphics_core-0b75ae2412192dbc.rlib" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/libaz-ae2afb26aa1ca46a.rlib" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/liblibc-bcfccfaeff17cb80.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd-ed4e5bf94d2d8a70.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libpanic_unwind-bebdd5eea372668b.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libobject-3355bc0b98aa4a8c.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libmemchr-0b5aa3d64bc8a557.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libaddr2line-f641304dbaaf4a6c.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libgimli-93e9b8c66d37f69d.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/librustc_demangle-50982f8036d6f83d.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd_detect-5eeb69397bccea91.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libhashbrown-2b679d626836b073.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libminiz_oxide-9a98cf221fb4b2c0.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libadler-b5dca51dab735af9.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-29342939a4c4f765.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libunwind-d8b64b175ae3dad2.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libcfg_if-1671a6ea0c5ac033.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/liblibc-e64d7cdeda4c1ec1.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/liballoc-def74c7c4b1b311e.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/librustc_std_workspace_core-18ea8bd63a028a62.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libcore-d20cd64dc93f727e.rlib" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib/libcompiler_builtins-b598f65ae2808d30.rlib" "-Wl,-Bdynamic" "-lstdc++" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/home/nicegraphi/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/aarch64-unknown-linux-gnu/lib" "-o" "/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/led_matrix-c1e7d078d0007520" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro,-znow" "-nodefaultlibs"
  = note: /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib(led-matrix-c.o): Relocations in generic ELF (EM: 62)
          /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib(led-matrix-c.o): Relocations in generic ELF (EM: 62)
          /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib(led-matrix-c.o): Relocations in generic ELF (EM: 62)
          /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib(led-matrix-c.o): Relocations in generic ELF (EM: 62)
          /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib(led-matrix-c.o): Relocations in generic ELF (EM: 62)
          /usr/lib/gcc/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-d20828d1ca08a5b2.rlib: error adding symbols: file in wrong format
          collect2: error: ld returned 1 exit status
          

error: could not compile `led_matrix` due to previous error

Verbose output of compiling

       Fresh winapi-build v0.1.1
       Fresh winapi v0.2.8
       Fresh tinyvec_macros v0.1.0
       Fresh kernel32-sys v0.2.2
       Fresh tinyvec v1.6.0
       Fresh walkdir v0.1.8
       Fresh unicode-normalization v0.1.22
       Fresh copy_dir v0.1.2
       Fresh unicode-bidi v0.3.8
       Fresh percent-encoding v2.2.0
       Fresh form_urlencoded v1.1.0
       Fresh memchr v2.5.0
       Fresh idna v0.3.0
       Fresh libc v0.2.137
       Fresh az v1.2.1
       Fresh byteorder v1.4.3
       Fresh bytes v1.3.0
       Fresh embedded-graphics-core v0.3.3
       Fresh rpi-led-matrix-sys v0.2.1
       Fresh url v2.3.1
       Fresh combine v4.6.6
       Fresh ryu v1.0.11
       Fresh itoa v1.0.4
       Fresh sha1_smol v1.0.0
       Fresh redis v0.22.1
       Fresh rpi-led-matrix v0.4.0
   Compiling led_matrix v0.1.0 (/home/nicegraphi/Code/rust/LedMatrixInf)
     Running `rustc --crate-name led_matrix --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=967c1c49fdc89db5 -C extra-filename=-967c1c49fdc89db5 --out-dir /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps --target aarch64-unknown-linux-gnu -C linker=aarch64-linux-gnu-gcc -C incremental=/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/incremental -L dependency=/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps -L dependency=/home/nicegraphi/Code/rust/LedMatrixInf/target/debug/deps --extern redis=/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/libredis-c9a0c1f937416ca7.rlib --extern rpi_led_matrix=/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix-2975166824ff955d.rlib -L native=/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/build/rpi-led-matrix-sys-950d1431edd7ee32/out/cpp-library/lib`

My cross compiling set up for the target aarch64-linux-gnu-gcc

I develop on fedora 37.

• I tried to compile with copr provided cross compiler. Link.
• I tried to compile with the rust tool "cross" Link.

Both approaches yield the same error.

[BoolPurist]

Now I can cross compile.
Solution: I had to include the c-stub feature for this crate via this line in the Cargo.toml file.

rpi-led-matrix = { version="0.4.0", default-features=true, features=["c-stubs"] }

However this of course stops linking to c++ library.

[TDHolmes]

I also have not been able to cross compile before, thus the existence of the c-stubs for compilation in CI. I never dug in very much as to why to be honest.

I wonder if the library produced assumes 32 bit? I don't recall what rpi I used to use for this development.

Can you run file on librpi_led_matrix_sys-d20828d1ca08a5b2.rlib?

[TDHolmes]

Have you tried enabling the feature for statically linking to c++ std lib?

[BoolPurist]

I also have not been able to cross compile before, thus the existence of the c-stubs for compilation in CI. I never dug in very much as to why to be honest.

I wonder if the library produced assumes 32 bit? I don't recall what rpi I used to use for this development.

Can you run file on librpi_led_matrix_sys-d20828d1ca08a5b2.rlib?

Jup can file this rlib file. Output of file command

file /home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-ca5e82262bd20cd5.rlib

is the following.

/home/nicegraphi/Code/rust/LedMatrixInf/target/aarch64-unknown-linux-gnu/debug/deps/librpi_led_matrix_sys-ca5e82262bd20cd5.rlib: current ar archive

[BoolPurist]

Have you tried enabling the feature for statically linking to c++ std lib?

Yes, i did.

If I only use the feature with statically linking to c++ std lib.

rpi-led-matrix = { version="0.4.0", default-features=true, features = ["stdcpp-static-link"] }

Then I get the following error message:

rror: could not find native static library `stdc++`, perhaps an -L flag is missing?

error: could not compile `rpi-led-matrix-sys` due to previous error
warning: build failed, waiting for other jobs to finish... 

If I use both feature with c-stubs and linking to c++ library statically

rpi-led-matrix = { version="0.4.0", default-features=true, features = ["stdcpp-static-link", "c-stubs"] }

then it compiles. My question is here, does it still link to the stubs or then to c++ library instead ?

[TDHolmes]

It'll only link to the C stubs. The rpi library depends on the C++ standard library, C stubs does not