global_asm-implemented extern "C" functions are not exported from dylib crates about rust HOT 5 OPEN

The same happens if you implement the function in a static library you link into the dylib. Rustc doesn't know that the function is defined within the dylib, so it doesn't mark it as exported in the version script.

from rust.

I think that behavior is fine in theory: there is no way for rust to know that the symbol is defined. but I believe there is currently a way to force the exporting of the symbol. E.g. this does not work

std::arch::global_asm! {
    ".global foo",
    "foo:",
    "ret",
}

extern "C" {
    #[export_name = "foo"]
    pub fn foo();
}

because

8 |     #[export_name = "foo"]
  |     ^^^^^^^^^^^^^^^^^^^^^^
9 |     pub fn foo();
  |     ------------- not a free function, impl method or static

So could it be a solution to provide a way to explicitly export the symbol?

from rust.

global_asm and static libraries should probably be handled the same for symbol export. You could look at the issue for the staticlib version of this behavior if such an option is already suggested.

from rust.

@bjorn3 would you mind linking the staticlib issue? I could not find it, unless you meant #104707 although that looks like the opposite problem to this one (too many exported symbols vs not enough).

from rust.

#78827, rust-lang/rfcs#2771, rust-lang/rfcs#3556

from rust.