[aidanhs]

Out of curiosity, what would you say the current state of the art is for full compilable decompilation? This is something I have a vague interest in but I'm not involved enough in the space to be on top of the latest and greatest tooling.

[feznyng]

Echoing IDA but its pricing is a huge PITA if you’re using it in a hobbyist capacity i.e. you don’t have an employer willing to pay for it. Could opt for the home version but that’s a yearly cost and you have to use their cloud decompiler. Ghidra’s your best bet if you want something FOSS and community-driven although not as great at decompilation.

[mdaniel]

Not only the pricing by itself, every story that I've heard about normal people trying to actually give them money is that they actually don't want to sell it to anyone other than big players

That said, depending on ones needs they do actually offer a slimmed down IDA Free: https://hex-rays.com/ida-free

I actually use AUR to more-or-less track its releases https://aur.archlinux.org/packages/ida-free

[D4Ha]

Hexrays used to be difficult to deal with if you want to purchase IDA Pro for the first time, due to their software getting leaked online.

They have eased the procedure to buy from them, but from time to time they'll ask you to fill out your info with national ID/passport (they say its because they don't want to sell their software to individuals under sanctions). This is despite them being based in Belgium (not the US).

For any serious work IDA Pro is highly suitable (the customization and scripting, loader examples and processor plugins...etc), on the other hand for side projects and basic security research Binary ninja and ghidra can go along way.

[carom]

Most decompilers do not strive for recompilability. [1] I believe there are (or were) some academic projects that aimed for recompilation as a core feature, but it is a hard problem.

On the commercial side, IDA / HexRays [2] is very strong for C-like decompilation. If you're looking at Go, Rust, or even C++ it is going to be a little bit more messy. As other commenters have said, you'll work function-by-function and it is expensive, though the free version does have decompilation (F5) for x86 and x64 (IIRC).

Binary Ninja [3] (no affiliation) is the coolest IMO, they have multiple intermediate representations they lift the assembly through. So you get like assembly -> low level IL -> medium level IL -> high level IL. There are also SSA forms (static single assignment) that can aid in programmatic analyses. The high level IL is very readable but makes no effort to be compilable as a programming language. That being said, Binary Ninja has implemented different "views" on the HLIL so you can show it as pseudo-C, Rust, etc. There is a free online version and the commercial version is cheaper than IDA but still expensive. Good Python API, good UI.

Ghidra [4] is the RE framework released by NSA. It is free and open source. It supports a ton of niche architectures. This is what most people use. I think the UI is awful, personally. It has a decompiler, the results are OK. They have an intermediate representation (P-Code) and plugins are in Java (since it is written in Java). I haven't worked much with it.

Most online decompilations you see for old games are likely using Ghidra, some might be using IDA. This is largely a manual process of doing a function at a time and building up the mental map of the program and how things interact.

Also worth mentioning are lifters. There were a few projects that aimed to lift assembly to LLVM IR (compiler framework's intermediate representation), with the idea being that then all your analyses could be written over LLVM IR as a lingua franca. Since it is in LLVM IR, it would be also recompilable and retargetable. [5][6]

1. https://reverseengineering.stackexchange.com/questions/2603/...

2. https://hex-rays.com/ida-free

3. https://binary.ninja/free/

4. https://ghidra-sre.org/

5. https://github.com/avast/retdec

6. https://github.com/lifting-bits/mcsema

[r00t-]

Meta has a foundation model trained on LLVM IR: https://ai.meta.com/research/publications/meta-large-languag...

[spectre9]

lol ok, now we’re getting into pure-nonsense territory

[michaeltlewis]

It's not clear to me why that is so. An LLM trained on IR for the purpose of compilation is not quite what we're looking for here but it is in the same territory.

[Retr0id]

Looking at an individual function, IDA hex-rays output is often recompilable as-is (or with minor modifications), but it won't necessarily be idiomatic, especially if you don't have symbol information.