Bootstrap rust for ARM64

[pranith]

I am trying to bootstrap rust for ARM64. I am trying to build an arm64 stage0 rustc on an x86 machine so that I can use that to natively compile rustc on ARM64. I have the aarch64-linux-gnu-gcc cross compiler installed. I am configuring rust as follows:

$ ../configure --host=aarch64-unknown-linux-gnu --target=aarch64-unknown-linux-gnu --disable-jemalloc

On building using make, I am getting the following error:

error: linking with `aarch64-linux-gnu-gcc` failed: exit code: 1
note: "aarch64-linux-gnu-gcc" "-Wl,--as-needed" "-L" "rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib" "x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/std-a5fc0d6c.0.o" "-o" "x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/libstd-a5fc0d6c.so" "x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/std-a5fc0d6c.metadata.o" "-Wl,-O1" "-nodefaultlibs" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/libcollections-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/liballoc-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/librustc_unicode-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/liballoc_system-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/liblibc-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/librand-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.0Icc9db0gqxD/libcore-a5fc0d6c.rlib" "-Wl,--no-whole-archive" "-L" "aarch64-unknown-linux-gnu/rt" "-L" "rust/build/aarch64-unknown-linux-gnu/llvm/Release/lib" "-L" "rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib" "-L" "rust/build/.rust/lib/aarch64-unknown-linux-gnu" "-L" "rust/build/lib/aarch64-unknown-linux-gnu" "-Wl,-Bstatic" "-Wl,--whole-archive" "-l" "rust_builtin" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "-l" "backtrace" "-Wl,--no-whole-archive" "-Wl,-Bdynamic" "-l" "dl" "-l" "pthread" "-l" "rt" "-l" "gcc_s" "-l" "c" "-l" "m" "-shared" "-l" "compiler-rt"
note: /usr/lib/gcc-cross/aarch64-linux-gnu/4.8/../../../../aarch64-linux-gnu/bin/ld: skipping incompatible rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/libcompiler-rt.a when searching for -lcompiler-rt
/usr/lib/gcc-cross/aarch64-linux-gnu/4.8/../../../../aarch64-linux-gnu/bin/ld: skipping incompatible aarch64-unknown-linux-gnu/rt/libcompiler-rt.a when searching for -lcompiler-rt
/usr/lib/gcc-cross/aarch64-linux-gnu/4.8/../../../../aarch64-linux-gnu/bin/ld: skipping incompatible rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/libcompiler-rt.a when searching for -lcompiler-rt
/usr/lib/gcc-cross/aarch64-linux-gnu/4.8/../../../../aarch64-linux-gnu/bin/ld: cannot find -lcompiler-rt
collect2: error: ld returned 1 exit status

error: aborting due to previous error
fatal runtime error: Could not unwind stack, error = 5
Illegal instruction (core dumped)
make: *** [x86_64-unknown-linux-gnu/stage1/lib/rustlib/aarch64-unknown-linux-gnu/lib/stamp.std] Error 132
make: *** Waiting for unfinished jobs....

Any ideas on how to fix this? Thanks!

[steveklabnik]

/cc @alexcrichton

[alexcrichton]

Unfortunately it's a currently known bug in our build system that we can't cross-compile a compiler for a target which can't actually be run on the host. In this case you're indicating that via --host=.... You may want instead to just generate a compiler which can target ARM64, in which case you only need to pass --target=....

As this is a known bug with the build system (#5258), however, I'm going to close this for now.