fix "still mutable" ice while metrics are enabled

[yaahc]

Resolves "still mutable" ICE discovered by @matthiaskrgr here: #t-docs-rs > metrics intitiative @ 💬

This was caused by invoking crate_hash before the definitions struct was frozen here:

rust/compiler/rustc_interface/src/passes.rs

Line 951 in e643f59

tcx.untracked().definitions.freeze();

resolved by moving metrics dumping to occur after analysis freezes the definitions

I'm guessing we didn't discover this in CI because the problem only occurs when you try to calculate the crash hash with incremental compilation enabled when it tries to freeze the definitions here:

rust/compiler/rustc_middle/src/hir/map.rs

Line 1172 in e643f59

let definitions = tcx.untracked().definitions.freeze();

my understanding is that this causes us to freeze the definitions too early in compilation, then we subsequently try to mutate them, likely during analysis, and this causes the ICE.

r? @bjorn3

[compiler-errors]

Are there any run-make tests for these metrics flags? It would be nice to have a test for this to actually show that this flag works without ICEing in incremental.

[yaahc]

Are there any run-make tests for these metrics flags? It would be nice to have a test for this to actually show that this flag works without ICEing in incremental.

we have a run-make test but I doubt it enables incremental compilation. I can enable that, question is do I just do that on the same test, do I create a second otherwise identical test that uses incremental, or is there some way to make the test run twice, once with and once without incremental compilation enabled?

[compiler-errors]

A second test is best, minimized to whatever you need to repro the breakage. Also probably best to check that it faithfully reproduces the ICE without the change in this PR.

[matthiaskrgr]

maybe we could also change "still mutable" to be slightly more descriptive? 😅

[yaahc]

maybe we could also change "still mutable" to be slightly more descriptive? 😅

probably something like "freezelock should not be frozen since we're still trying to write to it"

[rustbot]

This PR modifies run-make tests.

cc @jieyouxu

[yaahc]

I got it btw, I needed a late bound parameter which seemed to be the common factor in both of the repros I encountered

https://github.com./rust-lang/rust/pull/139502/files#diff-c576e89e24b5bfa584fdb04e336f6768068b3abc216621232b1dcdc18a3e5315R14

[bjorn3]

@bors r+

[bors]

📌 Commit 6f55015 has been approved by bjorn3

It is now in the queue for this repository.