Introduce tcx.get_diagnostic_name

[camsteffen]

Introduces a "reverse lookup" for diagnostic items. This is mainly intended for @rust-lang/clippy which often does a long series of is_diagnostic_item calls for the same DefId.

r? @oli-obk

[oli-obk]

Nice!

Two (not really important things):

• do we want to get rid of is_diagnostic_item, to nudge ppl to using one of the other two functions?
• it may be good from an API perspective to make the fields private and add a setter that inserts into both at the same time.

But these don't need to happen, let's get this rolling first and update clippy and stuff.

@bors r+

[bors]

📌 Commit 76dc8699a5446753b21873b938f696ecd6571bc7 has been approved by oli-obk

[oli-obk]

@bors r-

[oli-obk]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit 76dc8699a5446753b21873b938f696ecd6571bc7 with merge c6f2cb4408076901a5429245f87b314372eed6fc...

[camsteffen]

do we want to get rid of is_diagnostic_item, to nudge ppl to using one of the other two functions?

I think is_diagnostic_item will still be useful for a lot of cases.

it may be good from an API perspective to make the fields private and add a setter that inserts into both at the same time

I didn't do this because we only observe the insert return value for one of the maps, so putting an API layer there feels a little weird. And we only insert in one place.

[camsteffen]

@bors ping

[bors]

😪 I'm awake I'm awake

[camsteffen]

@rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[camsteffen]

@bors try

[bors]

⌛ Trying commit 76dc8699a5446753b21873b938f696ecd6571bc7 with merge 65a46a09ff197696229f1abbd888ff7fbee2b777...

[bors]

☀️ Try build successful - checks-actions
Build commit: 65a46a09ff197696229f1abbd888ff7fbee2b777 (65a46a09ff197696229f1abbd888ff7fbee2b777)

[rust-timer]

Queued 65a46a09ff197696229f1abbd888ff7fbee2b777 with parent 55111d6, future comparison URL.

[rust-timer]

Finished benchmarking commit (65a46a09ff197696229f1abbd888ff7fbee2b777): comparison url.

Summary: This change led to moderate relevant mixed results 🤷 in compiler performance.

• Moderate improvement in instruction counts (up to -3.0% on incr-full builds of ctfe-stress-4)
• Small regression in instruction counts (up to 0.6% on incr-unchanged builds of helloworld)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

[bors]

⌛ Trying commit b6cab80 with merge f108b6525490526153b5efa677b3ecfc9ac2ea71...

[camsteffen]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit a8d8bfd with merge 7633f3a38960dc501c2a2111fd8496abd90553ff...

[bors]

☀️ Try build successful - checks-actions
Build commit: 7633f3a38960dc501c2a2111fd8496abd90553ff (7633f3a38960dc501c2a2111fd8496abd90553ff)

[rust-timer]

Queued 7633f3a38960dc501c2a2111fd8496abd90553ff with parent d7539a6, future comparison URL.

[rust-timer]

Finished benchmarking commit (7633f3a38960dc501c2a2111fd8496abd90553ff): comparison url.

Summary: This change led to large relevant improvements 🎉 in compiler performance.

• Large improvement in instruction counts (up to -3.4% on incr-full builds of ctfe-stress-4)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf -perf-regression

[camsteffen]

My first compiler perf improvement! ☺️

[oli-obk]

Very nice!

@bors r+

[bors]

📌 Commit a8d8bfd has been approved by oli-obk

[bors]

⌛ Testing commit a8d8bfd with merge 0157cc9...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 0157cc9 to master...

[rust-timer]

Finished benchmarking commit (0157cc9): comparison url.

Summary: This change led to large relevant mixed results 🤷 in compiler performance.

• Large improvement in instruction counts (up to -3.4% on incr-full builds of ctfe-stress-4)
• Small regression in instruction counts (up to 0.4% on incr-unchanged builds of helloworld)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression