All versions of LLVM 18 have a bug where the __prefetch intrinsic has the wrong definition. This bug was fixed in https://github.com/llvm/llvm-project/pull/93235, but will not be released until LLVM 19 comes out.
When bindgen invokes clang to parse the headers, it looks like clang is actually using its bugged intrin.h which brings in the invalid signature for __prefetch. This leads to the failure to generate bindings for any header that pulls in msvc's intrin.h on aarch64. I attempted to use clang's -fno-builtin arg to prevent bindgen from pulling in the wrong definition of __prefetch, but it seems to not have any effect here.
Bindgen Invocation
use std::env;
use std::path::PathBuf;
fn main() {
let bindings = bindgen::Builder::default()
.header_contents(
"input.h",
r#"
void __prefetch(const void *);"#,
)
.parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
.clang_args([
"-fms-compatibility",
"-fms-extensions",
"-fdelayed-template-parsing",
"-fno-builtin", // attempt to prevent intrin.h from clang from being used (not working)
"-fno-builtin-__prefetch" // another not working attempt
])
.generate()
.expect("Unable to generate bindings");
let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
bindings
.write_to_file(out_path.join("bindings.rs"))
.expect("Couldn't write bindings!");
}
Actual Results
cargo build --target aarch64-pc-windows-msvc
Compiling bindgen-test v0.1.0 (D:\git-repos\bindgen-test)
error: failed to run custom build command for `bindgen-test v0.1.0 (D:\git-repos\bindgen-test)`
Caused by:
process didn't exit successfully: `D:\git-repos\bindgen-test\target\debug\build\bindgen-test-28575ca189a67a38\build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-env-changed=TARGET
cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS_aarch64-pc-windows-msvc
cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS_aarch64_pc_windows_msvc
cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS
--- stderr
D:\git-repos\bindgen-test\input.h:2:6: error: conflicting types for '__prefetch'
D:\git-repos\bindgen-test\input.h:2:6: note: '__prefetch' is a builtin with type 'void (void *)'
thread 'main' panicked at build.rs:23:10:
Unable to generate bindings: ClangDiagnostic("D:\\git-repos\\bindgen-test\\input.h:2:6: error: conflicting types for '__prefetch'\n")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
All versions of LLVM 18 have a bug where the
__prefetch
intrinsic has the wrong definition. This bug was fixed in https://github.com/llvm/llvm-project/pull/93235, but will not be released until LLVM 19 comes out.When
bindgen
invokesclang
to parse the headers, it looks likeclang
is actually using its buggedintrin.h
which brings in the invalid signature for__prefetch
. This leads to the failure to generate bindings for any header that pulls in msvc'sintrin.h
onaarch64
. I attempted to useclang
's-fno-builtin
arg to preventbindgen
from pulling in the wrong definition of__prefetch
, but it seems to not have any effect here.Bindgen Invocation
Actual Results
Expected Results
Should compile sucessfully