rust/tests/run-make/cdylib-fewer-symbols/foo.rs

#![crate_type = "cdylib"]

#[no_mangle]
pub extern "C" fn foo() -> u32 {
    3
}
rustc: Handle some libstd symbole exports better Right now symbol exports, particularly in a cdylib, are handled by assuming that `pub extern` combined with `#[no_mangle]` means "export this". This isn't actually what we want for some symbols that the standard library uses to implement itself, for example symbols related to allocation. Additionally other special symbols like `rust_eh_personallity` have no need to be exported from cdylib crate types (only needed in dylib crate types). This commit updates how rustc handles these special symbols by adding to the hardcoded logic of symbols like `rust_eh_personallity` but also adding a new attribute, `#[rustc_std_internal_symbol]`, which forces the export level to be considered the same as all other Rust functions instead of looking like a C function. The eventual goal here is to prevent functions like `__rdl_alloc` from showing up as part of a Rust cdylib as it's just an internal implementation detail. This then further allows such symbols to get gc'd by the linker when creating a cdylib. 2017-11-01 15:16:36 -05:00			`#![crate_type = "cdylib"]`

			`#[no_mangle]`
Update code to account for extern ABI requirement 2020-09-01 16:28:11 -05:00			`pub extern "C" fn foo() -> u32 {`
rustc: Handle some libstd symbole exports better Right now symbol exports, particularly in a cdylib, are handled by assuming that `pub extern` combined with `#[no_mangle]` means "export this". This isn't actually what we want for some symbols that the standard library uses to implement itself, for example symbols related to allocation. Additionally other special symbols like `rust_eh_personallity` have no need to be exported from cdylib crate types (only needed in dylib crate types). This commit updates how rustc handles these special symbols by adding to the hardcoded logic of symbols like `rust_eh_personallity` but also adding a new attribute, `#[rustc_std_internal_symbol]`, which forces the export level to be considered the same as all other Rust functions instead of looking like a C function. The eventual goal here is to prevent functions like `__rdl_alloc` from showing up as part of a Rust cdylib as it's just an internal implementation detail. This then further allows such symbols to get gc'd by the linker when creating a cdylib. 2017-11-01 15:16:36 -05:00			`3`
			`}`