gdbstub VS prusti-dev

now integrate gdbstub to support debugging code inside the emulator :)

Shameless plug, but have you considered integrating gdbstub rather than rolling your own debugger? I know a couple folks out there have successfully integrated it into their PS1 emulators with great success.

I've worked really hard to keep gdbstub panic free in its minimal configuration, going so far as to write some informal scripts that parse rustc's asm output to scan for the presence of panicking code paths.

crates.io | docs | repo

As a totally shameless plug, I'm the maintainer of gdbstub, a bare-metal, no_std, no_alloc, and size-optimized implementation of the GDB Remote Serial Protocol. One of the major changes slated for the upcoming release 0.6 is support for a new state-machine based API, which makes it possible to drive gdbstub directly via bare metal interrupt handlers (i.e: send/recv data over UART, handling breakpoints via the undefined instruction trap interrupt, etc...).

Continue working on a new API in gdbstub that'll make it easier to use directly from an interrupt handler when debugging code in a no_std, bare-metal OS environment.

I ran into almost this exact same problem while working on gdbstub, whereby I an API that allowed users to mix/match protocol features however they wanted, while also preventing users from accidentally implementing mutually-exclusive features. Moreover, I wanted to have a "zero cost" way to enable/disable API features without relying on cargo features. The solution I came up with is something I've been calling "Inlineable Dyn Extension Traits", or IDETs.

For a concrete example of how smart the Rust compiler is, I have a small writeup + test-repo that benchmarks a technique I came up with while working on gdbstub that [ab]uses the compiler's devirtualization and inlining optimizations to create runtime feature flags that are entirely compiled out if hard-coded to false at runtime.

> The overall goal would be to figure out classical error conditions like nill pointers deference.

> If I can figure out if a pointer will be nil in some execution branch, there is no reason why a computer cannot do the same.

Note, this is called flow-sensitive typing (also called type narrowing) and I think that typescript does it.

https://en.wikipedia.org/wiki/Flow-sensitive_typing

> I personally would see this as an human race level upgrades. Imagine feeding your code to a CI that spit back something like: "you will have a panic at line 156 when your input is > 4"

A model checker can do that!

See this

https://model-checking.github.io/kani/tutorial-kinds-of-fail...

Other techniques are also possible

https://github.com/viperproject/prusti-dev#quick-example

(Here I could link a lot of things, I just selected two Rust projects to illustrate)

This works better if you are able to provide contracts in your API that says which guarantees you provide. Alternatively, asserts are useful too.

You might be interested in the Prusti project, which statically checks for absence of reachable panics, overflows etc. It also allows user-defined specifications such as pre and post-conditions, loop body invariants, termination checking and so on.

https://github.com/viperproject/prusti-dev

This is called refinement types and prusti might be the project you saw.

But there's also a lot of exciting work around formal verification like Prusti.

prusti

Efforts: seL4, Project Everest, the Prossimo project of the ISRG, Let's Encrypt, and Prusti for the Rust language

Wow that sounds really cool! I'm not an expert but does that mean that one day you could implement dependend types or refinement types in Rust as a crate ? I currently only know of tools like: Flux Creusot Kani Prusti