Bug Reporting, Documentation, and Minimizing Rust Code

Once you have a minimized reproducer (`mwe.ll` or `reduced.ll`), you can delve deeper: - **manual editing:** try manually rewriting the llvm-ir. for certain issues, like those involving indirect calls, you might investigate enzyme-specific intrinsics like `__enzyme_virtualreverse`. Understanding how to use these might require consulting enzyme's documentation or source code. - **enzyme test cases:** look for relevant test cases within the [enzyme repository](https://github.com/enzymead/enzyme/tree/main/enzyme/test) that might demonstrate the correct usage of features or intrinsics related to your problem. ## 5) Report your bug. Afterwards, you should be able to copy and paste your `mwe.ll` (or `reduced.ll`) example into our [compiler explorer](https://enzyme.mit.edu/explorer/). - Select `llvm ir` as language and `opt 20` as compiler. - Replace the field to the right of your compiler with `-passes="enzyme"`, if it is not already set. - Hopefully, you will see once again your now familiar error. - Please use the share button to copy links to them. - Please create an issue on [https://github.com/enzymead/enzyme/issues](https://github.com/enzymead/enzyme/issues) and share `mwe.ll` and (if you have it) `reduced.ll`, as well as links to the compiler explorer. Please feel free to also add your rust code or a link to it. #### Documenting findings some enzyme errors, like `"attempting to call an indirect active function whose runtime value is inactive"`, have historically caused confusion. If you investigate such an issue, even if you don't find a complete solution, please consider documenting your findings. If the insights are general to enzyme and not specific to its rust usage, contributing them to the main [enzyme documentation](https://github.com/enzymead/www) is often the best first step. You can also mention your findings in the relevant enzyme github issue or propose updates to these docs if appropriate. This helps prevent others from starting from scratch. With a clear reproducer and documentation, hopefully an enzyme developer will be able to fix your bug. Once that happens, the enzyme submodule inside the rust compiler will be updated, which should allow you to differentiate your rust code. Thanks for helping us to improve rust-ad. # Minimize rust code Beyond having a minimal llvm-ir reproducer, it is also helpful to have a minimal rust reproducer without dependencies. This allows us to add it as a test case to ci once we fix it, which avoids regressions for the future. There are a few solutions to help you with minimizing the rust reproducer. This is probably the most simple automated approach: [cargo-minimize](https://github.com/nilstrieb/cargo-minimize). Otherwise we have various alternatives, including [`treereduce`](https://github.com/langston-barrett/treereduce), [`halfempty`](https://github.com/googleprojectzero/halfempty), or [`picireny`](https://github.com/renatahodovan/picireny), potentially also [`creduce`](https://github.com/csmith-project/creduce).

This section provides a detailed guide on reporting bugs found while using Enzyme, emphasizing the importance of creating a minimal LLVM IR reproducer and sharing it through the compiler explorer and GitHub issues. It also encourages documenting findings to aid others and contribute to the Enzyme documentation. Furthermore, the section covers the significance of minimizing the Rust code that triggers the bug and suggests various tools like `cargo-minimize`, `treereduce`, `halfempty`, `picireny`, and `creduce` to achieve this.