Copyright applies to literal reproduction of documents; not to ideas. It is straightforwardly allowed to read some implementation of an idea, think about it, and write your own implementation of the same idea.
IBM published its initial BIOS code in a manual bundled with the PC. Having any knowledge of it, even if you don't implement it verbatim makes you tainted, and makes you guilty in any of the subsequent cases.
This is why Black Box Reverse Engineering Exists.
Same is true for console reverse engineering. No self respecting reverse engineer reads code leaks from official console development. Otherwise they'd be in a legal hot water.
This is serious stuff and there's no blurry line in this.
I agree with all that (that is on actual legal basis, not personal preferences on societal structure), and it’s all the more frustrating to think about the power asymmetry in the era of LLM trained on basically every written material that can be found out there, and in that case oh yes you absolutely can go with it regardless of how verbatim some code they output can be.
The more disturbing thing about LLMs is, it's "fair-use" to scrape everything for them, but it's a liability for the user to use the code, text, whatever.
If it emits a large block of copyrighted material, you'll be again in legal hot water.
Considering even fair-use can be abused (see what GamersNexus is going through) at-will, it looks even more bleaker than at first glance.
So clean room the llvm analysis and work from a spec carried out of the room.
It's a really low bar to avoid, tbh. The point is that people have hobbies. And aspects of this work can look like a hobbyist "but i don't want to do it that way" view.
As a consumer of compiler products it doesn't have to matter to me, nor as a user of compilers. It's only observations reading the comments and the article which brought this to mind: llvm is proof by example and is a different kind of open source, it's not a barrier I would struggle to pierce, for my own personal view of code licences.
(I'm old enough to have read the gnu manifesto when it first published btw)
> It's of course not ridiculous.
I have the feeling you're arguing against and about something I never said.
To clarify, I'll restate: "I believe Linus has even opined that any filesystem which was developed after Linux, whose developers are aware of Linux, could be considered a 'derived work'. [The view that any new filesystem, simply aware of, but created independent of, and after Linux, is a derived work of Linux] is of course ridiculous,..."
> It's why black box reverse engineering exists and is generally legal, while white box reverse engineering is generally illegal.
Oh, I agree a clean room implementation is generally the best legal practice. I am just not sure there are cases on point that always require a clean room implementation, because I am aware of cases which expressly don't require clean room implementations (see Sony v. Connectix and Sega Enterprises Ltd. v. Accolade, Inc). And, given the factual situation has also likely changed due to FOSS and the Internet, I am saying some of these questions are likely still open, even if you regard them as closed.