Added rust phases diagram and explanation

[igaray]

• CoC read
• Included @ehuss 's diagram of rustc compilation phases and artifacts
• Added elaboration on stage naming convention
• Added content from Fix off-by-one-error in stage numbering between rustc-guide and rustbuild rust#57963

[spastorino]

The diagram was made by @ehuss, @nnethercote build a first explanation with text.
I was trying to ask in the other issue to @ehuss if you were comfortable by adding the diagram to rustc-guides.

[ehuss]

Sure, you're free to use it. Here's the source file if you want to edit it: https://gist.github.com/ehuss/70eafa935cf21f0d67533790dcafc18e That can be edited in https://www.draw.io/. Just keep in mind that this is a simplification. If there are non-host targets, its a bit different (described here), and passing flags like --keep-stage will change what happens. Also, rustdoc can be built at different stages depending on various things.

[igaray]

I'll add in those caveats, thank you

[mark-i-m]

Thanks! This is helpful addition.

A couple of small nits, but other than that r=me 🙂

[igaray]

Update: pushed some more content and almost done but still missing some important info and editing. Will r= when done.

[igaray]

r=mark-i-im

@jonas-schievink @dwijnand @mark-i-m @ehuss @Mark-Simulacrum
Please review the incorporated text, as they are based mostly off of your comments. I tried hard to be clear, non-repetitive and most of all, factually correct. I know the diff is large so if you have the opportunity maybe fetching the branch and reviewing the rendered markdown locally would be easier. Thank you for your time.

[mark-i-m]

Looks good to me :)

I’m fine with merging this now, but i will leave it open for a day or so for the others you cc’ed.

Thanks!

[ehuss]

I'm not sure I understand this sentence. rustc links to libstd/libcore?

[mark-i-m]

Yes, but IIUC, bootstrap treats libstd/libcore as "just another crate" that we are linking to our program. In other words, one can think of the compiler as a no_core program that cross-compiles and links with its own versions of the standard library.

[mark-i-m]

@igaray Sorry for the delay. Can you rebase? After that I think we can merge. This PR has already undergone more scrutiny than most.

Thanks for your patience!

[igaray]

Rebased but chalk links are broken again. Will rebase again after #322 is merged