bootstrap: sccache has no effect / RUSTC_WRAPPER not used?

[matthiaskrgr]

b389b0a

It seems that when doing a x.py build or check, RUSTC_WRAPPER is no longer used, so all calls go directly to rustc and not sccache rustc which would allow caching through sccache?

When building rustc, I could see that the sccache was neither utilized (no cache hits) nor fed with new artifacts (no cache misses)

[bjorn3]

I am pretty sure that sccache will either not be effective (it doesn't cache when --sysroot is passed) or cause actual issues (like not invalidating the cache if the standard library gets changed) if it were to be used.

[matthiaskrgr]

I'm wondering if #126476 is related. 🤔

@bjorn3 from just doing normal compiler bootstraps like x.py build/test/check I don't remember running into any frequent problems tbh 🤔