Rollup merge of #146178 - folkertdev:static-align, r=jdonszelmann,ralfjung,traviscross

Implement `#[rustc_align_static(N)]` on `static`s

Tracking issue: https://github.com/rust-lang/rust/issues/146177

```rust
#![feature(static_align)]

#[rustc_align_static(64)]
static SO_ALIGNED: u64 = 0;
```

We need a different attribute than `rustc_align` because unstable attributes are tied to their feature (we can't have two unstable features use the same unstable attribute). Otherwise this uses all of the same infrastructure as `#[rustc_align]`.

r? `@traviscross`

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/ui/attributes/malformed-static-align.rs b/tests/ui/attributes/malformed-static-align.rs
new file mode 100644
index 00000000000..305d8acf8af
--- /dev/null
+++ b/tests/ui/attributes/malformed-static-align.rs
@@ -0,0 +1,17 @@
+#![feature(static_align)]
+#![crate_type = "lib"]
+
+#[rustc_align_static = 16] //~ ERROR malformed `rustc_align_static` attribute input
+static S1: () = ();
+
+#[rustc_align_static("hello")] //~ ERROR invalid alignment value: not an unsuffixed integer
+static S2: () = ();
+
+#[rustc_align_static(0)] //~ ERROR invalid alignment value: not a power of two
+static S3: () = ();
+
+#[repr(align(16))] //~ ERROR `#[repr(align(...))]` is not supported on static
+static S4: () = ();
+
+#[rustc_align_static(16)] //~ ERROR `#[rustc_align_static]` attribute cannot be used on structs
+struct Struct1;