error out when repr(align) exceeds COFF limit

[nthery]

The PE-COFF binary format limits section alignment to 8192 bytes. Emit error when alignment exceeds this limit to avoid crash in llvm.

Closes #142386.

[rustbot]

r? @WaffleLapkin

rustbot has assigned @WaffleLapkin.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[rustbot]

Some changes occurred in diagnostic error codes

cc @GuillaumeGomez

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

[workingjubilee]

It only needs to error if we generate a static based on this.

[folkertdev]

Could you include testing alignment on functions here in this PR (if relevant, but I suspect it is). I think you can just add it to the test files you already modify.

#![feature(fn_align)]

// ...

// and then you can annotate a function with `#[repr(align(N))]`
#[repr(align(16))]
fn foo() {}

[workingjubilee]

@nthery This simple version that rejects repr(align(0x4000)) will need to be cratered. Nonetheless please finish writing up the PR so we can do so.

[workingjubilee]

...wait, we can't crater for Windows.

[workingjubilee]

fbbth.

[bors]

☔ The latest upstream changes (presumably #138165) made this pull request unmergeable. Please resolve the merge conflicts.

[nthery]

Could you include testing alignment on functions here in this PR (if relevant, but I suspect it is). I think you can just add it to the test files you already modify.

#![feature(fn_align)]

// ...

// and then you can annotate a function with `#[repr(align(N))]`
#[repr(align(16))]
fn foo() {}

It is relevant indeed. I reproduced the original bug with a function alignment exceeding 0x2000 bytes. Thanks for spotting this. I will add some test points.

[nthery]

I reckon I've addressed all points in the latest force-push.

[bors]

☔ The latest upstream changes (presumably #142906) made this pull request unmergeable. Please resolve the merge conflicts.