rust/tests/ui/link-native-libs/issue-70093/link-directives.rs

// Ensure that `#[link]` attributes are entirely ignore when using `-Zlink-directives=no`.

//@ run-pass
//@ compile-flags: -Zlink-directives=no
//@ ignore-fuchsia - missing __libc_start_main for some reason (#84733)
//@ ignore-cross-compile - default-linker-libraries=yes doesn't play well with cross compiling

// Usually these `#[link]` attribute would cause `libsome-random-non-existent-library`
// to be passed to the linker, causing it to fail because the file doesn't exist.
// However, with -Zlink-directives=no, the `#[link]` is ignored.
#[link(name = "some-random-non-existent-library", kind = "static")]
extern "C" {}

fn main() {}
Add comments to -Zlink-* tests 2024-12-31 02:25:35 +00:00			// Ensure that `#[link]` attributes are entirely ignore when using `-Zlink-directives=no`.

Implement -Zlink-native-libraries This implements a flag `-Zlink-native-libraries=yes/no`. If set to true/yes, or unspecified, then native libraries referenced via `#[link]` attributes will be put on the linker line (ie, unchanged behaviour). If `-Zlink-native-libraries=no` is specified then rustc will not add the native libraries to the link line. The assumption is that the outer build system driving the build already knows about the native libraries and will specify them to the linker directly (for example via `-Clink-arg=`). Addresses issue #70093 2020-03-18 02:10:56 +00:00			`//@ run-pass`
Implement -Zlink-directives=yes/no `-Zlink-directives=no` will ignored `#[link]` directives while compiling a crate, so nothing is emitted into the crate's metadata. The assumption is that the build system already knows about the crate's native dependencies and can provide them at link time without these directives. This is another way to address issue # #70093, which is currently addressed by `-Zlink-native-libraries` (implemented in #70095). The latter is implemented at link time, which has the effect of ignoring `#[link]` in every crate. This makes it a very large hammer as it requires all native dependencies to be known to the build system to be at all usable, including those in sysroot libraries. I think this means its effectively unused, and definitely under-used. Being able to control this on a crate-by-crate basis should make it much easier to apply when needed. I'm not sure if we need both mechanisms, but we can decide that later. 2023-02-04 23:07:41 +00:00			`//@ compile-flags: -Zlink-directives=no`
Fix up/ignore failing ui tests on fuchsia 2021-04-30 04:02:05 +00:00			`//@ ignore-fuchsia - missing __libc_start_main for some reason (#84733)`
Don't test -Cdefault-linker-libraries=yes when cross compiling. 2022-04-12 13:00:44 +00:00			`//@ ignore-cross-compile - default-linker-libraries=yes doesn't play well with cross compiling`
Implement -Zlink-native-libraries This implements a flag `-Zlink-native-libraries=yes/no`. If set to true/yes, or unspecified, then native libraries referenced via `#[link]` attributes will be put on the linker line (ie, unchanged behaviour). If `-Zlink-native-libraries=no` is specified then rustc will not add the native libraries to the link line. The assumption is that the outer build system driving the build already knows about the native libraries and will specify them to the linker directly (for example via `-Clink-arg=`). Addresses issue #70093 2020-03-18 02:10:56 +00:00
Add comments to -Zlink-* tests 2024-12-31 02:25:35 +00:00			// Usually these `#[link]` attribute would cause `libsome-random-non-existent-library`
			`// to be passed to the linker, causing it to fail because the file doesn't exist.`
			// However, with -Zlink-directives=no, the `#[link]` is ignored.
Implement -Zlink-native-libraries This implements a flag `-Zlink-native-libraries=yes/no`. If set to true/yes, or unspecified, then native libraries referenced via `#[link]` attributes will be put on the linker line (ie, unchanged behaviour). If `-Zlink-native-libraries=no` is specified then rustc will not add the native libraries to the link line. The assumption is that the outer build system driving the build already knows about the native libraries and will specify them to the linker directly (for example via `-Clink-arg=`). Addresses issue #70093 2020-03-18 02:10:56 +00:00			`#[link(name = "some-random-non-existent-library", kind = "static")]`
			`extern "C" {}`

			`fn main() {}`