Remove unused dependencies from compiler crates #86617

joshtriplett · 2021-06-25T07:57:08Z

Various compiler crates have dependencies that they don't appear to use. I used some scripting to detect such dependencies, filtered them based on some manual review, and removed those that do indeed appear to be entirely unused.

rust-highfive · 2021-06-25T07:57:11Z

r? @Mark-Simulacrum

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rustc_data_structures has a dependency on crossbeam-utils but never uses it. It appears to have originally had this dependency in order to set the "nightly" feature; however, its other dependencies use a different version of crossbeam-utils, so this doesn't actually affect anything. Furthermore, in current crossbeam-utils, the "nightly" feature has become a no-op.

joshtriplett · 2021-06-25T08:06:21Z

Updated Cargo.lock in each commit.

Useful command:

git rebase -i origin --exec 'cargo tree > /dev/null && git add Cargo.lock && git commit --amend --no-edit'

Unused since commit 622c48e ("Allow making `RUSTC_BOOTSTRAP` conditional on the crate name").

Unused since commit f141acf ("Move finalize_session_directory call out of cg_llvm").

…peck Unused since commit dc3eabd ("Store THIR in `IndexVec`s instead of an `Arena`").

Unused since commit 7d73e4c ("Remove ReScope").

Unused since commit 50e1ae1 ("Use ty::{IntTy,UintTy,FloatTy} in rustc").

Unused since commit cd7a011 ("Don't duplicate the extern providers once for each crate").

…log")

Unused since commit 8331dbe ("Add an Mmap wrapper to rustc_data_structures").

Unused since commit 4581d16 ("Move the query system to rustc_query_impl.").

Unused since commit 530a629 ("Remove pretty-print/reparse hack, and add derive-specific hack").

Unused since commit 6a32e79 ("stabilize union with 'ManuallyDrop' fields and 'impl Drop for Union'").

Unused since commit 64af7ea ("Move SanitizerSet to rustc_target").

Unused since commit 50e1ae1 ("Use ty::{IntTy,UintTy,FloatTy} in rustc").

joshtriplett · 2021-06-25T08:14:21Z

Dropped the removal of rustc_data_structures from rustc_attr, as it's used via derive(HashStable_Generic).

joshtriplett · 2021-06-25T08:57:48Z

@bors try @rust-timer queue

rust-timer · 2021-06-25T08:57:49Z

Awaiting bors try build completion.

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

bors · 2021-06-25T08:57:58Z

⌛ Trying commit 7a9d419 with merge 83f01bd5cc130c2f354a61775a6bb8dc2cf42b8f...

bors · 2021-06-25T09:46:10Z

☀️ Try build successful - checks-actions
Build commit: 83f01bd5cc130c2f354a61775a6bb8dc2cf42b8f (83f01bd5cc130c2f354a61775a6bb8dc2cf42b8f)

rust-timer · 2021-06-25T09:46:12Z

Queued 83f01bd5cc130c2f354a61775a6bb8dc2cf42b8f with parent 50a9081, future comparison URL.

compiler/rustc_lint_defs/Cargo.toml

rust-timer · 2021-06-25T12:03:13Z

Finished benchmarking try commit (83f01bd5cc130c2f354a61775a6bb8dc2cf42b8f): comparison url.

Summary: This benchmark run did not return any significant changes.

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. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

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

rustbot · 2021-06-25T12:03:14Z

Error: Label perf-regression can only be set by Rust team members

Please let @rust-lang/release know if you're having trouble with this bot.

JohnTitor · 2021-06-25T13:31:42Z

Label perf-regression can only be set by Rust team members

I just created the perf-regression label as it was missing.
@Mark-Simulacrum Is the perfbot considered as a team member? If not we should tweak the triagebot config.

JohnTitor · 2021-06-25T13:34:57Z

Although the bot said the result didn't have any significant changes, there're a lot of small regressions it seems.

joshtriplett · 2021-06-25T15:05:47Z

The benchmark results appear to be entirely noise/neutral, which is what I expected. I was primarily doing the perf run for the bootstrap timings; however, it looks like those timings are a simple sum of individual crate timings, which won't reflect any additional parallelism potentially made available by the looser dependencies.

Mark-Simulacrum · 2021-06-28T15:24:37Z

The benchmark results appear to be entirely noise/neutral, which is what I expected. I was primarily doing the perf run for the bootstrap timings; however, it looks like those timings are a simple sum of individual crate timings, which won't reflect any additional parallelism potentially made available by the looser dependencies.

Yes, we currently use -j1 to reduce noise in the bootstrap measurements.

@joshtriplett is there a reason this is still marked as a draft PR?

Mark-Simulacrum · 2021-06-28T15:25:03Z

(r=me if it's ready to go on your end)

…Mark-Simulacrum Allow anyone to set `perf-regression` label The main purpose is to allow the triage bot to set the label: rust-lang#86617 (comment) r? `@Mark-Simulacrum`

joshtriplett · 2021-06-28T19:35:37Z

Yes, we currently use -j1 to reduce noise in the bootstrap measurements.

I absolutely think that's the right thing to do in general. Is there some way to get perf measurements of a normal parallel build (and ideally the graph timings of "how early can things start"), without having to run them locally?

is there a reason this is still marked as a draft PR?

Just hadn't changed that yet. It started out as a draft because I wasn't sure if there were subtle dependencies I missed. I meant to change it to non-draft as soon as it built and showed a build performance improvement, and got distracted by the perf results not actually providing that information.

Mark-Simulacrum · 2021-06-28T19:37:05Z

I absolutely think that's the right thing to do in general. Is there some way to get perf measurements of a normal parallel build (and ideally the graph timings of "how early can things start"), without having to run them locally?

No, not really. We in theory could add support for one-off collection on perf, but it's not trivial and doesn't seem particularly warranted.

joshtriplett · 2021-06-30T20:58:49Z

@bors r=Mark-Simulacrum

bors · 2021-06-30T20:58:50Z

📌 Commit 7a9d419 has been approved by Mark-Simulacrum

bors · 2021-07-01T03:49:52Z

⌛ Testing commit 7a9d419 with merge 1034282...

bors · 2021-07-01T06:39:31Z

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 1034282 to master...

rust-highfive assigned Mark-Simulacrum Jun 25, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 25, 2021

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joshtriplett force-pushed the prune-dependencies branch from 241398e to 0f61739 Compare June 25, 2021 08:04

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joshtriplett added 14 commits June 25, 2021 01:12

rustc_codegen_llvm: Remove unused dependency rustc_feature

e37d6a9

Unused since commit 622c48e ("Allow making `RUSTC_BOOTSTRAP` conditional on the crate name").

rustc_codegen_llvm: Remove unused dependency rustc_incremental

aadbf75

Unused since commit f141acf ("Move finalize_session_directory call out of cg_llvm").

rustc_driver: Remove unused dependencies rustc_mir_build and rustc_ty…

8f7839f

…peck Unused since commit dc3eabd ("Store THIR in `IndexVec`s instead of an `Arena`").

rustc_infer: Remove unused dependency rustc_graphviz

b060ba9

Unused since commit 7d73e4c ("Remove ReScope").

rustc_infer: Remove unused dependency rustc_ast

40cc278

Unused since commit 50e1ae1 ("Use ty::{IntTy,UintTy,FloatTy} in rustc").

rustc_interface: Remove unused dependency rustc_index

b836ecd

Unused since commit cd7a011 ("Don't duplicate the extern providers once for each crate").

rustc_lint_defs: Remove apparently unused dependency on tracing (as "…

b29b3c1

…log")

rustc_metadata: Remove unused dependency stable_deref_trait

70e2683

Unused since commit 8331dbe ("Add an Mmap wrapper to rustc_data_structures").

rustc_middle: Remove unused dependency measureme

20cedd1

Unused since commit 4581d16 ("Move the query system to rustc_query_impl.").

rustc_parse: Remove unused dependency smallvec

7d75cac

Unused since commit 530a629 ("Remove pretty-print/reparse hack, and add derive-specific hack").

rustc_passes: Remove unused dependency rustc_trait_selection

f746012

Unused since commit 6a32e79 ("stabilize union with 'ManuallyDrop' fields and 'impl Drop for Union'").

rustc_session: Remove unused dependency bitflags

f20aec4

Unused since commit 64af7ea ("Move SanitizerSet to rustc_target").

rustc_query_impl: Remove unused dependencies

e721e15

rustc_symbol_mangling: Remove unused dependency rustc_ast

7a9d419

Unused since commit 50e1ae1 ("Use ty::{IntTy,UintTy,FloatTy} in rustc").

joshtriplett force-pushed the prune-dependencies branch from 0f61739 to 7a9d419 Compare June 25, 2021 08:13

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 25, 2021

Mark-Simulacrum reviewed Jun 25, 2021

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JohnTitor removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 25, 2021

JohnTitor mentioned this pull request Jun 28, 2021

Allow anyone to set perf-regression label #86687

Merged

Mark-Simulacrum added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 28, 2021

joshtriplett marked this pull request as ready for review June 28, 2021 19:31

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 30, 2021

bors added the merged-by-bors This PR was explicitly merged by bors. label Jul 1, 2021

bors merged commit 1034282 into rust-lang:master Jul 1, 2021

rustbot added this to the 1.55.0 milestone Jul 1, 2021

Remove unused dependencies from compiler crates #86617

Remove unused dependencies from compiler crates #86617

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