Bootstrap: verify that `--target` and `--host` triples are valid before starting a build

[tgross35]

I ran ./x dist --target mips64-openwrt-linux-musl --host x86_64-unknown-linux-gnu twice with slight different typos in the --host argument. Unfortunately, this takes about half an hour to detect (stage2, LLVM builds) and changing the host seems to invalidate some of the build.

Bootstrap can't actually query rustc for the target list, but it would be great if it could verify the triple string exists somewhere in compiler/rustc_target/src/spec/mod.rs as a sanity check before kicking off a multistage build.

@rustbot label +T-bootstrap +E-easy -needs-triage

[tgross35]

@rustbot label -needs-triage

[bjorn3]

The target may only exist in the compiler that will be built, so bootstrap would need to parse

rust/compiler/rustc_target/src/spec/mod.rs

Lines 1401 to 1689 in 4282576

	supported_targets! {
	("x86_64-unknown-linux-gnu", x86_64_unknown_linux_gnu),
	("x86_64-unknown-linux-gnux32", x86_64_unknown_linux_gnux32),
	("i686-unknown-linux-gnu", i686_unknown_linux_gnu),
	("i586-unknown-linux-gnu", i586_unknown_linux_gnu),
	("loongarch64-unknown-linux-gnu", loongarch64_unknown_linux_gnu),
	("loongarch64-unknown-linux-musl", loongarch64_unknown_linux_musl),
	("m68k-unknown-linux-gnu", m68k_unknown_linux_gnu),
	("csky-unknown-linux-gnuabiv2", csky_unknown_linux_gnuabiv2),
	("csky-unknown-linux-gnuabiv2hf", csky_unknown_linux_gnuabiv2hf),
	("mips-unknown-linux-gnu", mips_unknown_linux_gnu),
	("mips64-unknown-linux-gnuabi64", mips64_unknown_linux_gnuabi64),
	("mips64el-unknown-linux-gnuabi64", mips64el_unknown_linux_gnuabi64),
	("mipsisa32r6-unknown-linux-gnu", mipsisa32r6_unknown_linux_gnu),
	("mipsisa32r6el-unknown-linux-gnu", mipsisa32r6el_unknown_linux_gnu),
	("mipsisa64r6-unknown-linux-gnuabi64", mipsisa64r6_unknown_linux_gnuabi64),
	("mipsisa64r6el-unknown-linux-gnuabi64", mipsisa64r6el_unknown_linux_gnuabi64),
	("mipsel-unknown-linux-gnu", mipsel_unknown_linux_gnu),
	("powerpc-unknown-linux-gnu", powerpc_unknown_linux_gnu),
	("powerpc-unknown-linux-gnuspe", powerpc_unknown_linux_gnuspe),
	("powerpc-unknown-linux-musl", powerpc_unknown_linux_musl),
	("powerpc64-ibm-aix", powerpc64_ibm_aix),
	("powerpc64-unknown-linux-gnu", powerpc64_unknown_linux_gnu),
	("powerpc64-unknown-linux-musl", powerpc64_unknown_linux_musl),
	("powerpc64le-unknown-linux-gnu", powerpc64le_unknown_linux_gnu),
	("powerpc64le-unknown-linux-musl", powerpc64le_unknown_linux_musl),
	("s390x-unknown-linux-gnu", s390x_unknown_linux_gnu),
	("s390x-unknown-linux-musl", s390x_unknown_linux_musl),
	("sparc-unknown-linux-gnu", sparc_unknown_linux_gnu),
	("sparc64-unknown-linux-gnu", sparc64_unknown_linux_gnu),
	("arm-unknown-linux-gnueabi", arm_unknown_linux_gnueabi),
	("arm-unknown-linux-gnueabihf", arm_unknown_linux_gnueabihf),
	("armeb-unknown-linux-gnueabi", armeb_unknown_linux_gnueabi),
	("arm-unknown-linux-musleabi", arm_unknown_linux_musleabi),
	("arm-unknown-linux-musleabihf", arm_unknown_linux_musleabihf),
	("armv4t-unknown-linux-gnueabi", armv4t_unknown_linux_gnueabi),
	("armv5te-unknown-linux-gnueabi", armv5te_unknown_linux_gnueabi),
	("armv5te-unknown-linux-musleabi", armv5te_unknown_linux_musleabi),
	("armv5te-unknown-linux-uclibceabi", armv5te_unknown_linux_uclibceabi),
	("armv7-unknown-linux-gnueabi", armv7_unknown_linux_gnueabi),
	("armv7-unknown-linux-gnueabihf", armv7_unknown_linux_gnueabihf),
	("thumbv7neon-unknown-linux-gnueabihf", thumbv7neon_unknown_linux_gnueabihf),
	("thumbv7neon-unknown-linux-musleabihf", thumbv7neon_unknown_linux_musleabihf),
	("armv7-unknown-linux-musleabi", armv7_unknown_linux_musleabi),
	("armv7-unknown-linux-musleabihf", armv7_unknown_linux_musleabihf),
	("aarch64-unknown-linux-gnu", aarch64_unknown_linux_gnu),
	("aarch64-unknown-linux-musl", aarch64_unknown_linux_musl),
	("x86_64-unknown-linux-musl", x86_64_unknown_linux_musl),
	("i686-unknown-linux-musl", i686_unknown_linux_musl),
	("i586-unknown-linux-musl", i586_unknown_linux_musl),
	("mips-unknown-linux-musl", mips_unknown_linux_musl),
	("mipsel-unknown-linux-musl", mipsel_unknown_linux_musl),
	("mips64-unknown-linux-muslabi64", mips64_unknown_linux_muslabi64),
	("mips64el-unknown-linux-muslabi64", mips64el_unknown_linux_muslabi64),
	("hexagon-unknown-linux-musl", hexagon_unknown_linux_musl),
	("hexagon-unknown-none-elf", hexagon_unknown_none_elf),
	("mips-unknown-linux-uclibc", mips_unknown_linux_uclibc),
	("mipsel-unknown-linux-uclibc", mipsel_unknown_linux_uclibc),
	("i686-linux-android", i686_linux_android),
	("x86_64-linux-android", x86_64_linux_android),
	("arm-linux-androideabi", arm_linux_androideabi),
	("armv7-linux-androideabi", armv7_linux_androideabi),
	("thumbv7neon-linux-androideabi", thumbv7neon_linux_androideabi),
	("aarch64-linux-android", aarch64_linux_android),
	("riscv64-linux-android", riscv64_linux_android),
	("aarch64-unknown-freebsd", aarch64_unknown_freebsd),
	("armv6-unknown-freebsd", armv6_unknown_freebsd),
	("armv7-unknown-freebsd", armv7_unknown_freebsd),
	("i686-unknown-freebsd", i686_unknown_freebsd),
	("powerpc-unknown-freebsd", powerpc_unknown_freebsd),
	("powerpc64-unknown-freebsd", powerpc64_unknown_freebsd),
	("powerpc64le-unknown-freebsd", powerpc64le_unknown_freebsd),
	("riscv64gc-unknown-freebsd", riscv64gc_unknown_freebsd),
	("x86_64-unknown-freebsd", x86_64_unknown_freebsd),
	("x86_64-unknown-dragonfly", x86_64_unknown_dragonfly),
	("aarch64-unknown-openbsd", aarch64_unknown_openbsd),
	("i686-unknown-openbsd", i686_unknown_openbsd),
	("powerpc-unknown-openbsd", powerpc_unknown_openbsd),
	("powerpc64-unknown-openbsd", powerpc64_unknown_openbsd),
	("riscv64gc-unknown-openbsd", riscv64gc_unknown_openbsd),
	("sparc64-unknown-openbsd", sparc64_unknown_openbsd),
	("x86_64-unknown-openbsd", x86_64_unknown_openbsd),
	("aarch64-unknown-netbsd", aarch64_unknown_netbsd),
	("aarch64_be-unknown-netbsd", aarch64_be_unknown_netbsd),
	("armv6-unknown-netbsd-eabihf", armv6_unknown_netbsd_eabihf),
	("armv7-unknown-netbsd-eabihf", armv7_unknown_netbsd_eabihf),
	("i586-unknown-netbsd", i586_unknown_netbsd),
	("i686-unknown-netbsd", i686_unknown_netbsd),
	("mipsel-unknown-netbsd", mipsel_unknown_netbsd),
	("powerpc-unknown-netbsd", powerpc_unknown_netbsd),
	("riscv64gc-unknown-netbsd", riscv64gc_unknown_netbsd),
	("sparc64-unknown-netbsd", sparc64_unknown_netbsd),
	("x86_64-unknown-netbsd", x86_64_unknown_netbsd),
	("i686-unknown-haiku", i686_unknown_haiku),
	("x86_64-unknown-haiku", x86_64_unknown_haiku),
	("i686-unknown-hurd-gnu", i686_unknown_hurd_gnu),
	("aarch64-apple-darwin", aarch64_apple_darwin),
	("arm64e-apple-darwin", arm64e_apple_darwin),
	("x86_64-apple-darwin", x86_64_apple_darwin),
	("x86_64h-apple-darwin", x86_64h_apple_darwin),
	("i686-apple-darwin", i686_apple_darwin),
	// FIXME(#106649): Remove aarch64-fuchsia in favor of aarch64-unknown-fuchsia
	("aarch64-fuchsia", aarch64_fuchsia),
	("aarch64-unknown-fuchsia", aarch64_unknown_fuchsia),
	("riscv64gc-unknown-fuchsia", riscv64gc_unknown_fuchsia),
	// FIXME(#106649): Remove x86_64-fuchsia in favor of x86_64-unknown-fuchsia
	("x86_64-fuchsia", x86_64_fuchsia),
	("x86_64-unknown-fuchsia", x86_64_unknown_fuchsia),
	("avr-unknown-gnu-atmega328", avr_unknown_gnu_atmega328),
	("x86_64-unknown-l4re-uclibc", x86_64_unknown_l4re_uclibc),
	("aarch64-unknown-redox", aarch64_unknown_redox),
	("x86_64-unknown-redox", x86_64_unknown_redox),
	("i386-apple-ios", i386_apple_ios),
	("x86_64-apple-ios", x86_64_apple_ios),
	("aarch64-apple-ios", aarch64_apple_ios),
	("arm64e-apple-ios", arm64e_apple_ios),
	("armv7s-apple-ios", armv7s_apple_ios),
	("x86_64-apple-ios-macabi", x86_64_apple_ios_macabi),
	("aarch64-apple-ios-macabi", aarch64_apple_ios_macabi),
	("aarch64-apple-ios-sim", aarch64_apple_ios_sim),
	("aarch64-apple-tvos", aarch64_apple_tvos),
	("aarch64-apple-tvos-sim", aarch64_apple_tvos_sim),
	("x86_64-apple-tvos", x86_64_apple_tvos),
	("armv7k-apple-watchos", armv7k_apple_watchos),
	("arm64_32-apple-watchos", arm64_32_apple_watchos),
	("x86_64-apple-watchos-sim", x86_64_apple_watchos_sim),
	("aarch64-apple-watchos", aarch64_apple_watchos),
	("aarch64-apple-watchos-sim", aarch64_apple_watchos_sim),
	("armebv7r-none-eabi", armebv7r_none_eabi),
	("armebv7r-none-eabihf", armebv7r_none_eabihf),
	("armv7r-none-eabi", armv7r_none_eabi),
	("armv7r-none-eabihf", armv7r_none_eabihf),
	("armv8r-none-eabihf", armv8r_none_eabihf),
	("x86_64-pc-solaris", x86_64_pc_solaris),
	("sparcv9-sun-solaris", sparcv9_sun_solaris),
	("x86_64-unknown-illumos", x86_64_unknown_illumos),
	("aarch64-unknown-illumos", aarch64_unknown_illumos),
	("x86_64-pc-windows-gnu", x86_64_pc_windows_gnu),
	("i686-pc-windows-gnu", i686_pc_windows_gnu),
	("i686-uwp-windows-gnu", i686_uwp_windows_gnu),
	("x86_64-uwp-windows-gnu", x86_64_uwp_windows_gnu),
	("aarch64-pc-windows-gnullvm", aarch64_pc_windows_gnullvm),
	("i686-pc-windows-gnullvm", i686_pc_windows_gnullvm),
	("x86_64-pc-windows-gnullvm", x86_64_pc_windows_gnullvm),
	("aarch64-pc-windows-msvc", aarch64_pc_windows_msvc),
	("aarch64-uwp-windows-msvc", aarch64_uwp_windows_msvc),
	("arm64ec-pc-windows-msvc", arm64ec_pc_windows_msvc),
	("x86_64-pc-windows-msvc", x86_64_pc_windows_msvc),
	("x86_64-uwp-windows-msvc", x86_64_uwp_windows_msvc),
	("x86_64-win7-windows-msvc", x86_64_win7_windows_msvc),
	("i686-pc-windows-msvc", i686_pc_windows_msvc),
	("i686-uwp-windows-msvc", i686_uwp_windows_msvc),
	("i686-win7-windows-msvc", i686_win7_windows_msvc),
	("i586-pc-windows-msvc", i586_pc_windows_msvc),
	("thumbv7a-pc-windows-msvc", thumbv7a_pc_windows_msvc),
	("thumbv7a-uwp-windows-msvc", thumbv7a_uwp_windows_msvc),
	("wasm32-unknown-emscripten", wasm32_unknown_emscripten),
	("wasm32-unknown-unknown", wasm32_unknown_unknown),
	("wasm32-wasi", wasm32_wasi),
	("wasm32-wasip1", wasm32_wasip1),
	("wasm32-wasip2", wasm32_wasip2),
	("wasm32-wasi-preview1-threads", wasm32_wasi_preview1_threads),
	("wasm64-unknown-unknown", wasm64_unknown_unknown),
	("thumbv6m-none-eabi", thumbv6m_none_eabi),
	("thumbv7m-none-eabi", thumbv7m_none_eabi),
	("thumbv7em-none-eabi", thumbv7em_none_eabi),
	("thumbv7em-none-eabihf", thumbv7em_none_eabihf),
	("thumbv8m.base-none-eabi", thumbv8m_base_none_eabi),
	("thumbv8m.main-none-eabi", thumbv8m_main_none_eabi),
	("thumbv8m.main-none-eabihf", thumbv8m_main_none_eabihf),
	("armv7a-none-eabi", armv7a_none_eabi),
	("armv7a-none-eabihf", armv7a_none_eabihf),
	("msp430-none-elf", msp430_none_elf),
	("aarch64-unknown-hermit", aarch64_unknown_hermit),
	("riscv64gc-unknown-hermit", riscv64gc_unknown_hermit),
	("x86_64-unknown-hermit", x86_64_unknown_hermit),
	("x86_64-unikraft-linux-musl", x86_64_unikraft_linux_musl),
	("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
	("riscv32im-risc0-zkvm-elf", riscv32im_risc0_zkvm_elf),
	("riscv32im-unknown-none-elf", riscv32im_unknown_none_elf),
	("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
	("riscv32imc-esp-espidf", riscv32imc_esp_espidf),
	("riscv32imac-esp-espidf", riscv32imac_esp_espidf),
	("riscv32imafc-esp-espidf", riscv32imafc_esp_espidf),
	("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
	("riscv32imafc-unknown-none-elf", riscv32imafc_unknown_none_elf),
	("riscv32imac-unknown-xous-elf", riscv32imac_unknown_xous_elf),
	("riscv32gc-unknown-linux-gnu", riscv32gc_unknown_linux_gnu),
	("riscv32gc-unknown-linux-musl", riscv32gc_unknown_linux_musl),
	("riscv64imac-unknown-none-elf", riscv64imac_unknown_none_elf),
	("riscv64gc-unknown-none-elf", riscv64gc_unknown_none_elf),
	("riscv64gc-unknown-linux-gnu", riscv64gc_unknown_linux_gnu),
	("riscv64gc-unknown-linux-musl", riscv64gc_unknown_linux_musl),
	("sparc-unknown-none-elf", sparc_unknown_none_elf),
	("loongarch64-unknown-none", loongarch64_unknown_none),
	("loongarch64-unknown-none-softfloat", loongarch64_unknown_none_softfloat),
	("aarch64-unknown-none", aarch64_unknown_none),
	("aarch64-unknown-none-softfloat", aarch64_unknown_none_softfloat),
	("x86_64-fortanix-unknown-sgx", x86_64_fortanix_unknown_sgx),
	("x86_64-unknown-uefi", x86_64_unknown_uefi),
	("i686-unknown-uefi", i686_unknown_uefi),
	("aarch64-unknown-uefi", aarch64_unknown_uefi),
	("nvptx64-nvidia-cuda", nvptx64_nvidia_cuda),
	("i686-wrs-vxworks", i686_wrs_vxworks),
	("x86_64-wrs-vxworks", x86_64_wrs_vxworks),
	("armv7-wrs-vxworks-eabihf", armv7_wrs_vxworks_eabihf),
	("aarch64-wrs-vxworks", aarch64_wrs_vxworks),
	("powerpc-wrs-vxworks", powerpc_wrs_vxworks),
	("powerpc-wrs-vxworks-spe", powerpc_wrs_vxworks_spe),
	("powerpc64-wrs-vxworks", powerpc64_wrs_vxworks),
	("aarch64-kmc-solid_asp3", aarch64_kmc_solid_asp3),
	("armv7a-kmc-solid_asp3-eabi", armv7a_kmc_solid_asp3_eabi),
	("armv7a-kmc-solid_asp3-eabihf", armv7a_kmc_solid_asp3_eabihf),
	("mipsel-sony-psp", mipsel_sony_psp),
	("mipsel-sony-psx", mipsel_sony_psx),
	("mipsel-unknown-none", mipsel_unknown_none),
	("thumbv4t-none-eabi", thumbv4t_none_eabi),
	("armv4t-none-eabi", armv4t_none_eabi),
	("thumbv5te-none-eabi", thumbv5te_none_eabi),
	("armv5te-none-eabi", armv5te_none_eabi),
	("aarch64_be-unknown-linux-gnu", aarch64_be_unknown_linux_gnu),
	("aarch64-unknown-linux-gnu_ilp32", aarch64_unknown_linux_gnu_ilp32),
	("aarch64_be-unknown-linux-gnu_ilp32", aarch64_be_unknown_linux_gnu_ilp32),
	("bpfeb-unknown-none", bpfeb_unknown_none),
	("bpfel-unknown-none", bpfel_unknown_none),
	("armv6k-nintendo-3ds", armv6k_nintendo_3ds),
	("aarch64-nintendo-switch-freestanding", aarch64_nintendo_switch_freestanding),
	("armv7-sony-vita-newlibeabihf", armv7_sony_vita_newlibeabihf),
	("armv7-unknown-linux-uclibceabi", armv7_unknown_linux_uclibceabi),
	("armv7-unknown-linux-uclibceabihf", armv7_unknown_linux_uclibceabihf),
	("x86_64-unknown-none", x86_64_unknown_none),
	("aarch64-unknown-teeos", aarch64_unknown_teeos),
	("mips64-openwrt-linux-musl", mips64_openwrt_linux_musl),
	("aarch64-unknown-nto-qnx710", aarch64_unknown_nto_qnx710),
	("x86_64-pc-nto-qnx710", x86_64_pc_nto_qnx710),
	("i586-pc-nto-qnx700", i586_pc_nto_qnx700),
	("aarch64-unknown-linux-ohos", aarch64_unknown_linux_ohos),
	("armv7-unknown-linux-ohos", armv7_unknown_linux_ohos),
	("x86_64-unknown-linux-ohos", x86_64_unknown_linux_ohos),
	}

for this check rather than asking the bootstrap compiler. And I think it also needs to allow json target specs.

[Rajveer100]

@bjorn3
What would be the right place to detect this, i.e, to disallow initiating the build at the beginning itself if the --target or --host triple is invalid?

[bjorn3]

Other sanity checks are done in https://github.com/rust-lang/rust/blob/master/src/bootstrap/src/core/sanity.rs

[Rajveer100]

I believe the checks are being done here:

rust/src/bootstrap/src/core/sanity.rs

Line 162 in 703dc9c

for target in &build.targets {

rust/src/bootstrap/src/core/sanity.rs

Line 188 in 703dc9c

for host in &build.hosts {

Although, I am not quite sure about !build.config.dry_run()?

Since there are limited number of targets, do we just create some constant structure to store this and just map if it does not have any typos?

[tgross35]

I think you found the correct locations for such a check.

Although, I am not quite sure about !build.config.dry_run()?

./x takes a --dry-run flag that doesn't build anything. These checks should run even on dry run, so don't worry about that.

Since there are limited number of targets, do we just create some constant structure to store this and just map if it does not have any typos?

You could probably just use regex to extract a target list from the file linked in #122128 (comment), then add a check that the specified hosts and targets all exist in that list.

[onur-ozkan]

You could probably just use regex to extract a target list from the file linked in #122128 (comment), then add a check that the specified hosts and targets all exist in that list.

This approach is too straightforward; custom targets will fail from this logic.

[tgross35]

Do we have custom target info available early? If not, even a warning that something isn't in the list would be helpful here

[onur-ozkan]

Do we have custom target info available early? If not, even a warning that something isn't in the list would be helpful here

We do. #71009 can be a good ref to this.

Also, I don't think reading list from the compiler source file will be a good idea. Why not using someting like rustc --print target-list? That can give the built-in target list for the stage 0 compiler. EDIT: I just saw #122128 (comment), ignore my suggestion here.

[Rajveer100]

@onur-ozkan
I see this function:

rust/src/librustc_back/target/mod.rs

Line 293 in 61aeab4

pub fn search(target: &str) -> Result<Target, String> {

Do we just use this for the search part?

[bjorn3]

That is a 10 year old commit...