Static rustc_lint::builtin::BINARY_ASM_LABELS

pub static BINARY_ASM_LABELS: &Lint

The binary_asm_labels lint detects the use of numeric labels containing only binary digits in the inline asm! macro.

Example

#![cfg(target_arch = "x86_64")]

use std::arch::asm;

fn main() {
    unsafe {
        asm!("0: jmp 0b");
    }
}

This will produce:

error: avoid using labels containing only the digits `0` and `1` in inline assembly
 --> <source>:7:15
  |
7 |         asm!("0: jmp 0b");
  |               ^ use a different label that doesn't start with `0` or `1`
  |
  = help: start numbering with `2` instead
  = note: an LLVM bug makes these labels ambiguous with a binary literal number on x86
  = note: see <https://github.com/llvm/llvm-project/issues/99547> for more information
  = note: `#[deny(binary_asm_labels)]` on by default

Explanation

An LLVM bug causes this code to fail to compile because it interprets the 0b as a binary literal instead of a reference to the previous local label 0. To work around this bug, don’t use labels that could be confused with a binary literal.

This behavior is platform-specific to x86 and x86-64.

See the explanation in Rust By Example for more details.