Tracking Issue for `asm!` `interpolate`

The feature gate for the issue is #![feature(asm_interpolate)].

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
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Description

This feature adds a new interpolate operator for inline ASM. This operator copies const strings verbatim into the assembly.

unsafe {
    let a: usize;
    asm!("{} {}, 42", interpolate "mov", out(reg) a);
    assert_eq!(a, 42);

    const MOV: &str = "mov";
    let a: usize;
    asm!("{} {}, 42", interpolate MOV, out(reg) a);
    assert_eq!(a, 42);
}

Steps

• Implementation: https://github.com/rust-lang/rust/pull/156719
• Adjust documentation (see instructions on rustc-dev-guide)
• Style updates for any new syntax (nightly-style-procedure)
  • Style team decision on new formatting
  • Formatting for new syntax has been added to the Style Guide
  • (non-blocking) Formatting has been implemented in rustfmt
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

• Bikeshedding interpolate. Maybe verbatim?

Implementation history

• https://github.com/rust-lang/rust/pull/156719

Start with the implementation tracked in rust-lang/rust#156719, then review the stabilization and documentation instructions linked in this issue. The remaining work spans documentation, the Style Guide and rustfmt, stabilization, and the unresolved choice between interpolate and verbatim; completion means the applicable checklist items are resolved.