Undefined temporary symbol `$BB342_17` when compiling `rustc-demangle`

[AaronKutch]

Checklist

• I've looked through the issues and pull requests for similar reports

Describe your issue

When I run cross test --target mips-unknown-linux-gnu -Z build-std=core,alloc,proc_macro,std --features=std,zeroize_support,rand_support,serde_support,dag,try_support,debug on awint v0.12.0 (AaronKutch/awint@74f41a5 ) and cargo 1.74.0-nightly (925280f02 2023-08-25)

What target(s) are you cross-compiling for?

mips-unknown-linux-gnu

Which operating system is the host (e.g computer cross is on) running?

• macOS
• Windows
• Linux / BSD
• other OS (specify in description)

What architecture is the host?

• x86_64 / AMD64
• arm32
• arm64 (including Mac M1)

What container engine is cross using?

• docker
• podman
• other container engine (specify in description)

cross version

cross 2.5.0

Example

navigate to workspace root and run cross test --target mips-unknown-linux-gnu -Z build-std=core,alloc,proc_macro,std --features=std,zeroize_support,rand_support,serde_support,dag,try_support,debug
I get the result

error: Undefined temporary symbol $BB342_17

error: could not compile `rustc-demangle` (lib) due to previous error

Additional information / notes

No response

[AaronKutch]

I know that mips was demoted recently, this isn't necessary if I could run s390x-unknown-linux-gnu (I need a 32-bit big endian system) which seems to be blocked by the libtest issues

[taiki-e]

This is rustc/llvm bug, and can be worked around by enabling optimization.
rust-lang/rust#108835 (comment)

[urosbericsyrmia]

This issue should be fixed by llvm/llvm-project#80799.
Initially, the cause of the issue and the solution are explained in llvm/llvm-project#80666, but more elegant solution is just to remove derived isBlockOnlyReachableByFallthrough for Mips architecture.