Add test for raw-dylib with an external variable

[dpaoliello]

All existing tests of link kind raw-dylib only validate the ability to link against functions, but it is also possible to link against variables.

This adds tests for linking against a variable using raw-dylib both by-name and by-ordinal.

[rust-highfive]

r? @Mark-Simulacrum

(rust-highfive has picked a reviewer for you, use r? to override)

[dpaoliello]

r? @michaelwoerister

[chenyukang]

I have a question,

#![feature(raw_dylib)]

#[link(name = "exporter", kind = "raw-dylib")]
extern {
    #[link_ordinal(1, 2)]
    fn imported_function();
}

fn main() {}

Will trigger an error:

error: incorrect number of arguments to `#[link_ordinal]`
 --> src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs:5:5
  |
5 |     #[link_ordinal(1, 2)]
  |     ^^^^^^^^^^^^^^^^^^^^^
  |
  = note: the attribute requires exactly one argument

error: aborting due to 2 previous errors; 1 warning emitted

But when it's used for a static variable, it won't tigger error:

#![feature(raw_dylib)]

#[link(name = "exporter", kind = "raw-dylib")]
extern {
    #[link_ordinal(1, 2)]
    static mut imported_variable: i32;
}

fn main() {}

[dpaoliello]

But when it's used for a static variable, it won't tigger error:

Well spotted - looks like there is a bug where we aren't checking attributes on ForeignStatic items at all.

[michaelwoerister]

But when it's used for a static variable, it won't tigger error:

Well spotted - looks like there is a bug where we aren't checking attributes on ForeignStatic items at all.

I assume this is the fix for that?

Thanks a lot, @dpaoliello!
@bors r+

[bors]

📌 Commit 0a754b3 has been approved by michaelwoerister

It is now in the queue for this repository.

[bors]

⌛ Testing commit 0a754b3 with merge d77da9d...

[bors]

☀️ Test successful - checks-actions
Approved by: michaelwoerister
Pushing d77da9d to master...

[dpaoliello]

But when it's used for a static variable, it won't tigger error:

Well spotted - looks like there is a bug where we aren't checking attributes on ForeignStatic items at all.

I assume this is the fix for that?

Correct

[rust-timer]

Finished benchmarking commit (d77da9d): comparison url.

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: 😿 relevant regressions found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	2.4%	3.1%	32
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: mixed results

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	2.8%	2.9%	2
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-4.6%	-4.6%	1
All 😿🎉 (primary)	N/A	N/A	0

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

Footnotes

1. the arithmetic mean of the percent change ↩ ↩²

2. number of relevant changes ↩ ↩²