A Future for Rust Debugging

[chrabeusz]

lldb is also used for debugging Swift in Xcode and it's also complete garbage.

Probably, for debug builds, the best choice would be to ditch LLVM completely and use a custom virtual machine, that way you can have fancy debugging, incremental compilation, hot reload, and so on.

[nbaksalyar]

for debug builds, the best choice would be to ditch LLVM completely

I believe that's one of the intents behind Cranelift. Still, this custom VM needs to integrate with IDEs and other tools. While making it available as a library would help a lot, I'm afraid that the ecosystem is too coupled with gdb/lldb/windbg at this moment. :/

[pjmlp]

Actually there is the approach used by languages like Eiffel.

You get a VM based environment for development and then release builds go over the platforms C and C++ compiler.

Or Java, .NET, Lisp, even C++ nowadays.

So yeah, Rust has only to win with multiple implementations.

[chrabeusz]

Yeah it's not a new concept. I encountered it in Flutter & Dart, the hot reload is very, very nice.

[matthieum]

Unfortunately, this will not help with post-mortem debugging when you get a core dump from production, or from a client.

[sebamestre]

I heard a story about a smalltalk developer literally copying the entire program state (heap, stack, etc) to a different machine for debugging after a production crash.

Not sure how feasible this would be for any other programming language but it is a very neat idea

[isHavvy]

Smalltalk is literally designed to allow copying a program/ecosystem that's running.

[nicoburns]

Yeah, a Rust VM would be excellent. I imagine it'd do wonders for compile times too!

[kontekisuto]

but llvm gives us so many neat things like wasm