non-pub function no longer compiled in debug profile, causing link errors on thumbv7em-none-eabihf with defmt #131164
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I tried this code:
$ git clone https://github.com/ferrous-systems/rust-exercises.git
$ cd rust-exercises
$ git checkout v1.17.0
$ cd nrf52_code/radio_app
$ rustup target add thumbv7em-none-eabihf --toolchain=nightly
$ cargo install flip-link (or change `.cargo/config.toml` to not use flip-link - either is fine)
$ cargo +nightly buildI expected to see this happen:
The binaries build like, they do on stable.
Instead, this happened:
= note: rust-lld: error: /Users/jonathan/Documents/clients/training/open-rust-embedded-2024-10-02/rust-exercises-v1.17.0/nrf52-code/radio-app/target/thumbv7em-none-eabihf/debug/build/defmt-36a2ab5d209daca3/out/defmt.x:7: symbol not found: __defmt_default_panic
rust-lld: error: /Users/jonathan/Documents/clients/training/open-rust-embedded-2024-10-02/rust-exercises-v1.17.0/nrf52-code/radio-app/target/thumbv7em-none-eabihf/debug/build/defmt-36a2ab5d209daca3/out/defmt.x:7: symbol not found: __defmt_default_panic
rust-lld: error: /Users/jonathan/Documents/clients/training/open-rust-embedded-2024-10-02/rust-exercises-v1.17.0/nrf52-code/radio-app/target/thumbv7em-none-eabihf/debug/build/defmt-36a2ab5d209daca3/out/defmt.x:7: symbol not found: __defmt_default_panic
rust-lld: error: /Users/jonathan/Documents/clients/training/open-rust-embedded-2024-10-02/rust-exercises-v1.17.0/nrf52-code/radio-app/target/thumbv7em-none-eabihf/debug/build/defmt-36a2ab5d209daca3/out/defmt.x:7: symbol not found: __defmt_default_panic
That symbol is defined here: https://github.com/knurling-rs/defmt/blob/b7a89f56059fc66ac3c7cc3445d092829599e699/defmt/src/lib.rs#L365
Bisect
@Dirbaio said:
searched nightlies: from nightly-2024-07-30 to nightly-2024-10-02
regressed nightly: nightly-2024-08-01
searched commit range: f8060d2...28a58f2
regressed commit: 0b5eb7b
That's the LLVM 19 upgrade.
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Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues.Area: linking into static, shared libraries and binariesCategory: This is a bug.High priorityStatus: A Minimal Complete and Verifiable Example has been found for this issueRelevant to the compiler team, which will review and decide on the PR/issue.Performance or correctness regression from stable to beta.