OSX 上 MIPS MT7688 OpenWRT 的交叉编译 (mipsel-unknown-linux-musl)

Question

当我尝试使用 rustc 1.32.0-nightly 在 OSX 上为小端 MIPS（运行 OpenWRT 的 MT7688 处理器）交叉编译 Cargo starter main.rs 文件时，出现以下错误：

cargo build --target=mipsel-unknown-linux-musl
   Compiling led v0.1.0 (/Users/petrus/Projects/led)
error: linking with `cc` failed: exit code: 1
  |
  = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-L" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.2kthj4han7xcr84g.rcgu.o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.440j3fk0cam0b0pu.rcgu.o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.482rers61msj2848.rcgu.o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.498udk2wtgjsw4ib.rcgu.o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.4uh6jdaux45o6bh1.rcgu.o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.5fq5qqfqkwjepod2.rcgu.o" "-o" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps/led-fb2a88ec64854daf.49n6u1xnbbs66t12.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/Users/petrus/Projects/led/target/mipsel-unknown-linux-musl/debug/deps" "-L" "/Users/petrus/Projects/led/target/debug/deps" "-L" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-27a0dffe96f2ad3e.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libpanic_unwind-fe8b80af161a561e.rlib" "/var/folders/rl/b7dvjss14wj6415t0v4f7z3m0000gn/T/rustcFd840X/libunwind-ecc019d8c6cb3f8a.rlib" "/var/folders/rl/b7dvjss14wj6415t0v4f7z3m0000gn/T/rustcFd840X/liblibc-5d68beb2e4661bda.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/liballoc-de565f8c0b8e0971.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_core-0a55bee6cc97e346.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libcore-4075eb2b0854a330.rlib" "-Wl,--end-group" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libcompiler_builtins-ecf284221505c8a3.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lc"
  = note: clang: warning: argument unused during compilation: '-pie' [-Wunused-command-line-argument]
          ld: unknown option: --as-needed
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

运行时RUSTFLAGS="-C linker=lld"抛出：

RUSTFLAGS="-C linker=lld" cargo build --target=mipsel-unknown-linux-musl
   Compiling led v0.1.0 (/Users/petrus/Projects/led)
error: linker `lld` not found
  |
  = note: No such file or directory (os error 2)

error: aborting due to previous error

error: Could not compile `led`.

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

还尝试过RUSTFLAGS="-C linker=rust-lld"，它会抛出：

rust-lld: error: unable to find library -lgcc_s
rust-lld: error: unable to find library -lc

据我了解，我需要指定一个链接器工具链，但我不知道如何获取它。我还尝试使用 xargo 和 cross 以及 dockcross/linux-mipsel 进行编译，但没有成功。

我会在设备本身上构建它，但 rustup 不会在 MT7688 上安装 Rust。如何获取并指定正确的 MIPS（小端）链接器工具链？

更新：我发现了一个针对 macOS 的预编译 MIPS GCC，当我尝试指定时，它会抛出 `mipsel-elf/bin/ld: 无法识别的选项 '-Wl,--as-needed' 或“添加符号时出错：错误值” mipsel-elf-gcc 将其作为链接器：

rustc --target=mipsel-unknown-linux-musl -C linker=/Users/petrus/Projects/wallfly/respeaker/bin/gcc-mips/bin/mipsel-elf-gcc ./src/main.rs
error: linking with `/Users/petrus/Projects/bin/gcc-mips/bin/mipsel-elf-gcc` failed: exit code: 1
  |
  = note: "/Users/petrus/Projects/bin/gcc-mips/bin/mipsel-elf-gcc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-Wl,--eh-frame-hdr" "-L" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib" "main.main.7rcbfp3g-cgu.0.rcgu.o" "main.main.7rcbfp3g-cgu.1.rcgu.o" "main.main.7rcbfp3g-cgu.2.rcgu.o" "main.main.7rcbfp3g-cgu.3.rcgu.o" "main.main.7rcbfp3g-cgu.4.rcgu.o" "main.main.7rcbfp3g-cgu.5.rcgu.o" "-o" "main" "main.4s37gsrti678ik8u.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libstd-27a0dffe96f2ad3e.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libpanic_unwind-fe8b80af161a561e.rlib" "/var/folders/rl/b7dvjss14wj6415t0v4f7z3m0000gn/T/rustcLDTUyV/libunwind-ecc019d8c6cb3f8a.rlib" "/var/folders/rl/b7dvjss14wj6415t0v4f7z3m0000gn/T/rustcLDTUyV/liblibc-5d68beb2e4661bda.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/liballoc-de565f8c0b8e0971.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/librustc_std_workspace_core-0a55bee6cc97e346.rlib" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libcore-4075eb2b0854a330.rlib" "-Wl,--end-group" "/Users/petrus/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/mipsel-unknown-linux-musl/lib/libcompiler_builtins-ecf284221505c8a3.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lc"
  = note: /Users/petrus/Projects/bin/gcc-mips/bin/../lib/gcc/mipsel-elf/7.1.0/../../../../mipsel-elf/bin/ld: /Users/petrus/Projects/bin/gcc-mips/bin/../lib/gcc/mipsel-elf/7.1.0/crtbegin.o: relocation R_MIPS_HI16 against `a local symbol' can not be used when making a shared object; recompile with -fPIC
          /Users/petrus/Projects/bin/gcc-mips/bin/../lib/gcc/mipsel-elf/7.1.0/crtbegin.o: error adding symbols: Bad value
          collect2: error: ld returned 1 exit status

也许我指定错误？

Answer 1

尝试

cargo install cross

进而

cross build --release --target mipsel-unknown-linux-musl