rustc silently crashes with STATUS_ILLEGAL_INSTRUCTION when targeting thumbv7a-*-windows-msvc with raw-dylib

[bdbai]

I tried this code inside a cdylib crate in src/lib.rs:

#[no_mangle]
pub fn foo1() {
    #[link(name = "Kernel32.dll", kind = "raw-dylib", modifiers = "+verbatim")]
    extern "system" {
        #[link_name = "GetLastError"]
        pub fn get_last_error() -> i32;
    }
    unsafe { get_last_error() };
}

and then built the package targeting thumbv7a-uwp-windows-msvc:

cargo +nightly build -Z build-std=std,panic_abort --target thumbv7a-uwp-windows-msvc

A DLL is expected to be produced without any errors.

Instead, I was getting errors from cargo output:

error: could not compile `testlib` (lib)

Caused by:
  process didn't exit successfully: `rustc --crate-name testlib --edition=2021 src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=149 --crate-type cdylib --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=ef61da8a61eafeee --out-dir D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps --target thumbv7a-uwp-windows-msvc -C incremental=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\incremental -L dependency=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps -L dependency=D:\proj\testrs\testlib\target\debug\deps --extern noprelude:alloc=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\liballoc-d258b9239a7ba282.rlib --extern noprelude:compiler_builtins=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcompiler_builtins-f04b6bba69e7d7d9.rlib --extern noprelude:core=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcore-ce81669056b9279b.rlib --extern noprelude:panic_abort=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_abort-004c9cbe9edf74e5.rlib --extern noprelude:panic_unwind=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_unwind-36a0313086dccb8e.rlib --extern noprelude:proc_macro=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libproc_macro-47df777a82030abd.rlib --extern noprelude:std=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libstd-2dafaaca0018a6d9.rlib -Z unstable-options` (exit code: 0xc000001d, STATUS_ILLEGAL_INSTRUCTION)

Full output:

PS D:\proj\testrs\testlib> cargo +nightly build -Z build-std=std,panic_abort --target thumbv7a-uwp-windows-msvc Compiling core v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\core) Compiling rustc-std-workspace-core v1.99.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\rustc-std-workspace-core) Compiling compiler_builtins v0.1.105 Compiling libc v0.2.153 Compiling alloc v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\alloc) Compiling cfg-if v1.0.0 Compiling adler v1.0.2 Compiling memchr v2.5.0 Compiling rustc-demangle v0.1.23 Compiling unwind v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\unwind) Compiling rustc-std-workspace-alloc v1.99.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\rustc-std-workspace-alloc) Compiling panic_abort v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\panic_abort) Compiling panic_unwind v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\panic_unwind) Compiling gimli v0.28.0 Compiling miniz_oxide v0.7.1 Compiling object v0.32.2 Compiling std_detect v0.1.5 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\stdarch\crates\std_detect) Compiling hashbrown v0.14.3 Compiling addr2line v0.21.0 Compiling std v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\std) Compiling proc_macro v0.0.0 (C:\Users\bdbai\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\proc_macro) Compiling testlib v0.1.0 (D:\proj\testrs\testlib) error: could not compile `testlib` (lib)

Caused by:
process didn't exit successfully: rustc --crate-name testlib --edition=2021 src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=149 --crate-type cdylib --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=ef61da8a61eafeee --out-dir D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps --target thumbv7a-uwp-windows-msvc -C incremental=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\incremental -L dependency=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps -L dependency=D:\proj\testrs\testlib\target\debug\deps --extern noprelude:alloc=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\liballoc-d258b9239a7ba282.rlib --extern noprelude:compiler_builtins=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcompiler_builtins-f04b6bba69e7d7d9.rlib --extern noprelude:core=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcore-ce81669056b9279b.rlib --extern noprelude:panic_abort=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_abort-004c9cbe9edf74e5.rlib --extern noprelude:panic_unwind=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_unwind-36a0313086dccb8e.rlib --extern noprelude:proc_macro=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libproc_macro-47df777a82030abd.rlib --extern noprelude:std=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libstd-2dafaaca0018a6d9.rlib -Z unstable-options (exit code: 0xc000001d, STATUS_ILLEGAL_INSTRUCTION)


Meta

rustc +nightly --version --verbose:

rustc 1.78.0-nightly (6cc484351 2024-02-10)
binary: rustc
commit-hash: 6cc4843512d613f51ec81aba689180c31b0b28b6
commit-date: 2024-02-10
host: x86_64-pc-windows-msvc
release: 1.78.0-nightly
LLVM version: 17.0.6

I did not see any ICE, panic messages or stack traces, hence attached Visual Studio debugger to capture the exception:

Memory dump: https://1drv.ms/u/s!AvQksscT-2xElJJNe7C2yAEa9NV5BQ?e=dt93eH

rustc command line

rustc --crate-name testlib --edition=2021 src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=149 --crate-type cdylib --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=ef61da8a61eafeee --out-dir D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps --target thumbv7a-uwp-windows-msvc -C incremental=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\incremental -L dependency=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps -L dependency=D:\proj\testrs\testlib\target\debug\deps --extern noprelude:alloc=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\liballoc-d258b9239a7ba282.rlib --extern noprelude:compiler_builtins=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcompiler_builtins-f04b6bba69e7d7d9.rlib --extern noprelude:core=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libcore-ce81669056b9279b.rlib --extern noprelude:panic_abort=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_abort-004c9cbe9edf74e5.rlib --extern noprelude:panic_unwind=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libpanic_unwind-36a0313086dccb8e.rlib --extern noprelude:proc_macro=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libproc_macro-47df777a82030abd.rlib --extern noprelude:std=D:\proj\testrs\testlib\target\thumbv7a-uwp-windows-msvc\debug\deps\libstd-2dafaaca0018a6d9.rlib -Z unstable-options

[bjorn3]

Based on the crash location and https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/invalid-parameter-functions?view=msvc-170 it seems like LLVM passed an invalid argument to a libc function.

[bdbai]

Closing as no longer reproducible using latest nightly toolchain.