[BUG]: Rust-generated LLVM IR fails to demangle

[Alcaro]

Describe the bug

[BUG]: LLVM IR viewer on rustc uses C++ demangling

Steps to reproduce

#[inline(never)]
#[no_mangle]
pub fn _Z1ai() {}

#[inline(never)]
pub fn common_chars() -> Vec<String> {
    vec!["a".into(),"b".into()]
}

Expected behavior

_Z1ai

<alloc::vec::Vec<T,A> as core::ops::drop::Drop>::drop::h20f42961a44ccece

Actual behavior

define void @a(int)() unnamed_addr {

define void @"_ZN70_$LT$alloc..vec..Vec$LT$T$C$A$GT$$u20$as$u20$core..ops..drop..Drop$GT$4drop17h20f42961a44cceceE"(ptr noalias nocapture noundef readnone align 8 dereferenceable(24) %self) unnamed_addr {

Reproduction link

https://godbolt.org/z/h7PP4GTzn

Screenshots

Not applicable

Operating System

No response

Browser version

No response

[narpfel]

#6560 addresses the second case of quoted identifiers not being demangled.

The fix for the first case (non-Rust identifiers) is a bit more complicated; I’ve written some thoughts here: #6265 (comment)