Trying to compile Rust code for a RG300 console (retrofw buildroot, mipsel, uclibc...)

help
#1

I started a conversation on Reddit:

but I believe a forum is a better medium for this, as I'm likely to have ongoing doubts about this...

So I'm trying to build stuff for a RG-300 handheld console. It runs Linux and, for instance, comes with a wolf3d port:

$ file wolf3d/wolf3d
wolf3d/wolf3d: ELF 32-bit LSB executable, MIPS, MIPS32 version 1 (SYSV), dynamically linked, interpreter /lib/ld-uClibc.so.0, not stripped

I've been able to cross-compile mipsel-gnu binaries, but they don't seem to work. I don't think I have a good way to troubleshoot that, so I'm trying to cross-compile mipsel-musl binaries... while that's not uclibc like what the system runs, I suppose that could work?

I'm trying to write games, so the example I'm trying to compile is a rust-sdl2 example (actually, the "demo" example). I'm trying out various stuff, but the most promising one so far is:

$ CMAKE_C_COMPILER=mipsel-linux-gnu-gcc cargo build --release --example demo --target mipsel-unknown-linux-musl --features bundled
   Compiling sdl2-sys v0.32.6 (/home/alex/git/rust-sdl2/sdl2-sys)
   Compiling sdl2 v0.32.2 (/home/alex/git/rust-sdl2)
error: linking with `/usr/bin/mipsel-linux-gnu-gcc` failed: exit code: 1
  |
  = note: "/usr/bin/mipsel-linux-gnu-gcc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.0.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.1.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.10.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.11.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.12.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.13.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.14.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.15.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.2.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.3.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.4.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.5.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.6.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.7.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.8.rcgu.o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.demo.efjj4cfb-cgu.9.rcgu.o" "-o" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/examples/demo-cd3dc7739d2262b7.53ka2isznhz5ijg9.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps" "-L" "/home/alex/git/rust-sdl2/target/release/deps" "-L" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "-Wl,-Bstatic" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps/libsdl2-24fc8a218d815f7a.rlib" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps/libsdl2_sys-6322dfb6db2ec021.rlib" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps/libbitflags-cf0b9a229f903dd1.rlib" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps/liblazy_static-5ca797e4c59098f8.rlib" "/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/deps/liblibc-6c67bcfab9b7336f.rlib" "-Wl,--start-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libpanic_unwind-efbc2c947951b8cc.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libhashbrown-b177382d9a04ffbe.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_alloc-ba7d2244d33447d5.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace-39569dc87e4ea301.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace_sys-cd9e255bd82ddb5c.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_demangle-f83165e777dccb8d.rlib" "/tmp/rustcuPwFMj/libunwind-10b085de263b1750.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcfg_if-9a4a22edf44da957.rlib" "/tmp/rustcuPwFMj/liblibc-68fabc677efa98de.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/liballoc-026dc0061b48e8b6.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_core-7bf75bb619341145.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcore-ef54709e300503ed.rlib" "-Wl,--end-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcompiler_builtins-4ed27d8420cb4abc.rlib" "-Wl,-Bdynamic" "-lSDL2" "-lgcc_s" "-lc"
  = note: /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: skipping incompatible /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2.so when searching for -lSDL2
          /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: /home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib(std-b6414ae168385702.std.2w1w7wxd-cgu.0.rcgu.o): undefined reference to symbol 'dlsym@@GLIBC_2.0'
          /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: //lib/mipsel-linux-gnu/libdl.so.2: error adding symbols: DSO missing from command line
          collect2: error: ld returned 1 exit status
          

error: aborting due to previous error

error: could not compile `sdl2`.

To learn more, run the command again with --verbose.

I believe cmake (run through build.rs using the cmake crate) is ignoring the CMAKE_* env var and creating an x86-64 binary:

$ ls -l /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2.so
lrwxrwxrwx 1 alex alex 14 Jan  9 21:15 /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2.so -> libSDL2-2.0.so
alex@molly:~/git/rust-sdl2$ ls -l /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so
lrwxrwxrwx 1 alex alex 16 Jan  9 21:15 /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so -> libSDL2-2.0.so.0
alex@molly:~/git/rust-sdl2$ ls -l /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so.0
lrwxrwxrwx 1 alex alex 21 Jan  9 21:15 /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so.0 -> libSDL2-2.0.so.0.10.0
alex@molly:~/git/rust-sdl2$ file /home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so.0.10.0
/home/alex/git/rust-sdl2/target/mipsel-unknown-linux-musl/release/build/sdl2-sys-e7b69d6b74505090/out/lib/libSDL2-2.0.so.0.10.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=ee49ab77f8244d1db6123568a0f77fdd142cf7a4, not stripped

Any suggestions? The console comes with a buildroot system, but using an old version which doesn't seem to have Rust support...

#2

So I tried going back to buildroot again. Managed to set up a working buildroot for my device, and successfully modified an existing project written in C (using SDL1, I think) and deployed the modified version.

Now I built buildroot from master, which comes with support for building rustc/cargo:

$ cargo -Vv
cargo 0.26.0
release: 0.26.0
$ rustc -Vv
rustc 1.33.0 (2aa4c46cf 2019-02-28)
binary: rustc
commit-hash: 2aa4c46cfdd726e97360c2734835aa3515e8c858
commit-date: 2019-02-28
host: x86_64-unknown-linux-gnu
release: 1.33.0
LLVM version: 8.0

, which are not super recent, but workable, I guess. The problem is that buildroot apparently doesn't build std, so if I try:

~/git/rust-sdl2$ cargo build --example demo
   Compiling getrandom v0.1.14
   Compiling sdl2 v0.32.2 (file:///home/alex/git/rust-sdl2)
error[E0432]: unresolved import `std`
  --> /home/alex/.cargo/registry/src/github.com-1ecc6299db9ec823/getrandom-0.1.14/src/error_impls.rs:13:5
   |
13 | use std::io;
   |     ^^^ did you mean `self::std`?

error[E0432]: unresolved import `libc`
  --> /home/alex/.cargo/registry/src/github.com-1ecc6299db9ec823/getrandom-0.1.14/src/util_libc.rs:18:13
   |
18 |         use libc::__errno_location as errno_location;
   |             ^^^^ maybe a missing `extern crate libc;`?

, any pointers?

#3

Is there any way you could use musl-libc instead of uclibc? Because, otherwise, you're going to need to make a new target for the compiler.

Rust libstd is pretty tightly bound to the ABI of the libc right now, for complicated reasons like "errno looks like a variable but it's actually thread-local storage" and "what exactly is that typedef".

Rust currently had two Linux targets: one for glibc, and one for musl-libc.

#4

That's what I was trying to do before (first post), but I failed. However, I tried to do that without using buildroot.

I've backed a bit buildroot and it seems to be building now. If that fails, apparently buildroot supports glibc and musl too, so that might be worth trying...

#5

Ah, yes, now I get what you're doing.

I looked at the cmake crate's source code, and it does override the CMAKE_C_COMPILER. It uses the cc library to find the compiler, instead of just letting cmake do it.

The environment variable to configure the cc crate's compiler is just CC=mipsel-linux-gnu-gcc, according up its README.

#6

Ah, another thing to try! Thanks :slight_smile:

I think buildroot's a safer option for now (as I can build C projects with SDL, which is more than what I can do without buildroot right now), but if I hit a deadend there, I'll go back and try to do that- buildroot is more laborious.

#7

See:

http://lists.busybox.net/pipermail/buildroot/2020-January/271809.html

for some issues I'm having with buildroot (cc: @elebihan)

#8

Tried @notriddle's suggestion, but didn't go far. Tried to go to SDL 1.2, but again, libc binaries do not seem to work, and building on MUSL is problematic:

$ CC=mipsel-linux-gnu-gcc cargo build --release --target mipsel-unknown-linux-musl
...
   Compiling sdl-demo v0.3.5 (/home/alex/git/rust-sdl/src/sdl-demo)
error: linking with `mipsel-linux-gnu-gcc` failed: exit code: 1
  |
  = note: "mipsel-linux-gnu-gcc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.0.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.1.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.10.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.2.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.3.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.4.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.5.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.6.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.7.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.8.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.9.rcgu.o" "-o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.31k7m8xrreivxzrc.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps" "-L" "/home/alex/git/rust-sdl/src/sdl-demo/target/release/deps" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "-Wl,-Bstatic" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libsdl-8063a8b284d1b4d3.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum-cbfd187794706650.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_rational-bcdc5c44a48e52d6.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_bigint-099e4fe4aaf288f4.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_complex-9739b21091164cd4.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librustc_serialize-da9cc6e30a80c111.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_iter-d5c1e846c2502edf.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_integer-fe93e931c1d7da2c.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_traits-1830627636222f5b.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librand-7901db0b189caaac.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librand-9c7c8ac87d626c0d.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/liblibc-6c67bcfab9b7336f.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/liblibc-c3c01f36245aeb51.rlib" "-Wl,--start-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libpanic_unwind-efbc2c947951b8cc.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libhashbrown-b177382d9a04ffbe.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_alloc-ba7d2244d33447d5.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace-39569dc87e4ea301.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace_sys-cd9e255bd82ddb5c.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_demangle-f83165e777dccb8d.rlib" "/tmp/rustcPUPJo4/libunwind-10b085de263b1750.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcfg_if-9a4a22edf44da957.rlib" "/tmp/rustcPUPJo4/liblibc-68fabc677efa98de.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/liballoc-026dc0061b48e8b6.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_core-7bf75bb619341145.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcore-ef54709e300503ed.rlib" "-Wl,--end-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcompiler_builtins-4ed27d8420cb4abc.rlib" "-Wl,-Bdynamic" "-lSDL" "-lgcc_s" "-lc"
  = note: /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: /home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib(std-b6414ae168385702.std.2w1w7wxd-cgu.0.rcgu.o): undefined reference to symbol 'dlsym@@GLIBC_2.0'
          /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: //lib/mipsel-linux-gnu/libdl.so.2: error adding symbols: DSO missing from command line
          collect2: error: ld returned 1 exit status
#9

At least there's no line about "skipping incompatible library" this time.

Try adding #![link(name="dl", kind="dylib")] to your main.rs file.

#10

Nope, fails again, I think identically:

  = note: "mipsel-linux-gnu-gcc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.0.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.1.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.10.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.2.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.3.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.4.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.5.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.6.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.7.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.8.rcgu.o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.sdl_demo.379673b8-cgu.9.rcgu.o" "-o" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/sdl_demo-f55bf19366d03a2d.31k7m8xrreivxzrc.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps" "-L" "/home/alex/git/rust-sdl/src/sdl-demo/target/release/deps" "-L" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib" "-Wl,-Bstatic" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libsdl-8063a8b284d1b4d3.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum-cbfd187794706650.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_rational-bcdc5c44a48e52d6.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_bigint-099e4fe4aaf288f4.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_complex-9739b21091164cd4.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librustc_serialize-da9cc6e30a80c111.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_iter-d5c1e846c2502edf.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_integer-fe93e931c1d7da2c.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/libnum_traits-1830627636222f5b.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librand-7901db0b189caaac.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/librand-9c7c8ac87d626c0d.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/liblibc-6c67bcfab9b7336f.rlib" "/home/alex/git/rust-sdl/src/sdl-demo/target/mipsel-unknown-linux-musl/release/deps/liblibc-c3c01f36245aeb51.rlib" "-Wl,--start-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libpanic_unwind-efbc2c947951b8cc.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libhashbrown-b177382d9a04ffbe.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_alloc-ba7d2244d33447d5.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace-39569dc87e4ea301.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libbacktrace_sys-cd9e255bd82ddb5c.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_demangle-f83165e777dccb8d.rlib" "/tmp/rustcTd2PkH/libunwind-10b085de263b1750.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcfg_if-9a4a22edf44da957.rlib" "/tmp/rustcTd2PkH/liblibc-68fabc677efa98de.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/liballoc-026dc0061b48e8b6.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_core-7bf75bb619341145.rlib" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcore-ef54709e300503ed.rlib" "-Wl,--end-group" "/home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libcompiler_builtins-4ed27d8420cb4abc.rlib" "-Wl,-Bdynamic" "-lSDL" "-lgcc_s" "-lc"
  = note: /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: /home/alex/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-b6414ae168385702.rlib(std-b6414ae168385702.std.2w1w7wxd-cgu.0.rcgu.o): undefined reference to symbol 'dlsym@@GLIBC_2.0'
          /usr/lib/gcc-cross/mipsel-linux-gnu/8/../../../../mipsel-linux-gnu/bin/ld: //lib/mipsel-linux-gnu/libdl.so.2: error adding symbols: DSO missing from command line
          collect2: error: ld returned 1 exit status
#11

Well, adding some stuff to the source's .cargo/config allowed me to compile:

$ cat ../../.cargo/config
[build]
rustflags = ["-C", "link-args=-ldl -lutil -lpthread"]

The result is

target/mipsel-unknown-linux-musl/release/sdl-demo: ELF 32-bit LSB shared object, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked, interpreter /lib/ld.so.1, for GNU/Linux 3.2.0, BuildID[sha1]=36239a5af12cc0039a0725446fc473b1dc16ff1c, with debug_info, not stripped

But the resulting binary does not seem to work :frowning:

#12

musl must be linked statically, as there is no musl so on RG300 (it only has uclibc)

#13

Hi! You're the guy on the RetroFW discord, right?

Yeah, I guessed "dynamically-linked" was trouble :slight_smile: I think building statically-linked SDL stuff will be easier with rust-sdl2, instead of rust-sdl1, as that seems to be more suited for statically linking. I had some progress with:

export CC=mipsel-linux-gnu-gcc ; export CFLAGS="-DSDL_VIDEO_DRIVER_X11_SUPPORTS_GENERIC_EVENTS=1 -I/usr/lib/mipsel-linux-gnu/glib-2.0/include/" ; cargo build --release --target mipsel-unknown-linux-musl --example demo --features static-link,bundled

on rust-sdl2, but still no dice. And even if that works, I'm not sure SDL2 + musl will work on the RG300 (buildroot seems to support SDL2, but I'm not sure there's anything working on my RG300 with SDL2... everything seems to be using SDL1).

#14

Hi! You're the guy on the RetroFW discord, right?

Yeah that's me

I don't think anyone got SDL2 working on RetroFW yet. SDL1 static linking should work (just make sure you link the buildroot SDL, it comes with lots of patches https://github.com/retrofw/buildroot/tree/master/package/sdl)

DSDL_VIDEO_DRIVER_X11_SUPPORTS_GENERIC_EVENTS

There is also no X11 on RetroFW

#15

Yay, moved forward a bit. I can now build a program that draws a fuzzy red rectangle and crashes :smiley:

I've put some notes about it at:

https://github.com/alexpdp7/retrofw2-rust

, in case someone wants to follow along. However, it does seem that you can do RetroFW game development on Rust!

#16

The plot thickens. Most stuff I build crashes immediately. As I had my suspicions about rust-sdl being wonky, I tried playing with https://github.com/Roysten/rust-framebuffer .

Playing with that, I've been able to write a minimal program that crashes, which just does:

let x: i32 = unsafe { mem::zeroed() };
println!("{}", x);

, which according to zeroed in core::mem - Rust should be valid code, but that results in SIGILL (illegal instruction, apparently).

I can do prints and stuff to the console...

Anyone has any idea on how to proceed from there? (this is rustc 1.33.0 using mipsel-unknown-linux-uclibc , compiled using buildroot)

#17

The next step could be looking at the assembly to see which instruction is illegal.
RG300 has an Ingenic XBurst CPU (jz4760b) that supports MIPS32r2 instructions with lots of extensions.

#18

I tried RUSTFLAGS="--emit asm" cargo build... but it wasn't really obvious to me how to find out the instruction that causes the crash.

I was also doing debug builds. However, if I do a release build, mem::zeroed works (!).

I tried some other rust-framebuffer examples in release mode, and they continue failing, but in different places. Will poke at that a bit.

What I fear is that buildroot is building 1.33.0, which will soon be a year old, so even if I find the issue, I'll likely be told to update... so perhaps I should work on trying to get a more recent version of Rust working under buildroot...

#19

GDB will pause on SIGILL by default. For seeing asm in GDB see Show current assembly instruction in GDB - Stack Overflow

Upgrading Rust in the buildroot may not be that difficult, here is an example of updating a package in RetroFW buildroot: https://github.com/retrofw/buildroot/pull/6

#20

Nice. I'll poke around to see if I manage to run stuff using gdb (I suppose via telnet it will be possible).

I fear the patches that buildroot ships will no longer apply, but will give it a try...