coverage: Several small cleanups in `spans` #116754

Zalathar · 2023-10-15T06:58:22Z

While investigating the details of coverage span processing, I noticed several opportunities to make the code simpler and clearer.

@rustbot label +A-code-coverage

rustbot · 2023-10-15T06:58:32Z

r? @wesleywiser

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rustbot · 2023-10-15T06:58:34Z

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

compiler/rustc_mir_transform/src/coverage/spans.rs

Zalathar · 2023-10-15T08:04:17Z

Addressed review feedback (diff).

Zalathar · 2023-10-15T08:14:44Z

Switched over to an if-let chain in the early-exit logic (diff).

bors · 2023-10-15T16:13:00Z

☔ The latest upstream changes (presumably #116688) made this pull request unmergeable. Please resolve the merge conflicts.

compiler/rustc_mir_transform/src/coverage/spans.rs

oli-obk · 2023-10-16T07:41:24Z

compiler/rustc_mir_transform/src/coverage/spans.rs

                    debug!("    ...adding at least one pending={:?}", dup);
                    self.push_refined_span(dup);
                }
+                // The list of dups is now empty, but we can recycle its capacity.
+                assert!(pending_dups.is_empty() && self.pending_dups.is_empty());
+                self.pending_dups = pending_dups;
            } else {
                self.pending_dups.clear();


this is not necessary anymore, right? Could assert that it is empty instead of clearing it.

When this clear occurs, pending_dups should always be non-empty. We checked that it's non-empty at the top of the function, and in this branch we haven't tried to drain it.

(I wanted to prove this by adding the assert and having it fail, but this line doesn't seem to ever be executed by the current coverage test suite.)

This also makes me think that I should flatten the guard logic here too.

(I wanted to prove this by adding the assert and having it fail, but this line doesn't seem to ever be executed by the current coverage test suite.)

could assert it and wait for someone to report an issue with coverage 😆

Zalathar · 2023-10-16T09:32:09Z

Tweaked push_refined_span (diff).

Zalathar · 2023-10-16T09:49:53Z

Flattened the guard logic in check_pending_dups/maybe_flush_pending_dups (diff).

…_name_span`

This method's main responsibility is to flush the pending dups into refined spans, if appropriate.

…ing_dups`

This patch also sorts the constructor fields into declaration order.

It turns out that all of the `len` manipulation here was just reimplementing `last_mut`.

Zalathar · 2023-10-16T10:01:21Z

Hoisted all of the renames to the start of the PR, so other changes can consistently refer to the new name instead of the old one.

This span can always be retrieved from `prev`, so there is no need to store it separately.

This makes it easier to see that the non-initial cases assume that `prev` and `curr` are set, and all operate on the same prev/curr references.

This reduces clutter, and makes it easier to notice regions where mutations definitely don't occur.

Interacting with `basic_coverage_blocks` directly makes it easier to satisfy the borrow checker when mutating `pending_dups` while reading other fields.

Zalathar · 2023-10-16T10:08:09Z

Fixed indentation of a debug string (diff).

oli-obk · 2023-10-16T11:24:02Z

@bors r+

bors · 2023-10-16T11:24:04Z

📌 Commit 7aa1b83 has been approved by oli-obk

It is now in the queue for this repository.

…llaumeGomez Rollup of 6 pull requests Successful merges: - rust-lang#116754 (coverage: Several small cleanups in `spans`) - rust-lang#116798 (Improve display of parallel jobs in rustdoc-gui tester script) - rust-lang#116800 (Fix implied outlives check for GAT in RPITIT) - rust-lang#116805 (Make `rustc_onunimplemented` export path agnostic) - rust-lang#116808 (Add myself to smir triage) - rust-lang#116811 (Preserve unicode escapes in format string literals when pretty-printing AST) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#116754 - Zalathar:spans, r=oli-obk coverage: Several small cleanups in `spans` While investigating the details of coverage span processing, I noticed several opportunities to make the code simpler and clearer. --- `@rustbot` label +A-code-coverage

rustbot assigned wesleywiser Oct 15, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Oct 15, 2023

rustbot added the A-code-coverage Area: Source-based code coverage (-Cinstrument-coverage) label Oct 15, 2023

cjgillot reviewed Oct 15, 2023

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compiler/rustc_mir_transform/src/coverage/spans.rs Outdated Show resolved Hide resolved

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Zalathar force-pushed the spans branch from c0fec7c to 287a2e8 Compare October 15, 2023 08:03

Zalathar force-pushed the spans branch from 287a2e8 to c2b6e43 Compare October 15, 2023 08:13

Zalathar force-pushed the spans branch from c2b6e43 to 26b9855 Compare October 15, 2023 11:04

Zalathar force-pushed the spans branch from 26b9855 to 58f7c67 Compare October 15, 2023 22:55

oli-obk reviewed Oct 16, 2023

View reviewed changes

Zalathar force-pushed the spans branch 2 times, most recently from 395b5d2 to 8e19075 Compare October 16, 2023 09:31

Zalathar force-pushed the spans branch from 8e19075 to ce9b319 Compare October 16, 2023 09:48

Zalathar added 5 commits October 16, 2023 20:52

coverage: Rename check_invoked_macro_name_span to `maybe_push_macro…

46c545c

…_name_span`

coverage: Rename check_pending_dups to maybe_flush_pending_dups

9b6ce4f

This method's main responsibility is to flush the pending dups into refined spans, if appropriate.

coverage: Rename hold_pending_dups_unless_dominated to `update_pend…

d928d3e

…ing_dups`

coverage: Use DUMMY_SP instead of creating a dummy span manually

fa2e262

This patch also sorts the constructor fields into declaration order.

coverage: Simplify push_refined_span

5f1e8f9

It turns out that all of the `len` manipulation here was just reimplementing `last_mut`.

Zalathar force-pushed the spans branch from ce9b319 to 0f552df Compare October 16, 2023 10:00

Zalathar added 3 commits October 16, 2023 21:05

coverage: Flatten guard logic in maybe_push_macro_name_span

97d1a91

coverage: Flatten guard logic in maybe_flush_pending_dups

7bbe4be

coverage: Remove redundant field prev_expn_span

9bb27f3

This span can always be retrieved from `prev`, so there is no need to store it separately.

Zalathar added 6 commits October 16, 2023 21:05

coverage: Call prev/curr less in to_refined_spans

b1c44f4

This makes it easier to see that the non-initial cases assume that `prev` and `curr` are set, and all operate on the same prev/curr references.

coverage: Call prev/curr less in other places

41038db

This reduces clutter, and makes it easier to notice regions where mutations definitely don't occur.

coverage: Move take_curr and note what its callers are doing

25e6303

coverage: Inline prev_starts_after_next

4ab4273

coverage: Inline span_bcb_dominates

5e5a8e7

Interacting with `basic_coverage_blocks` directly makes it easier to satisfy the borrow checker when mutating `pending_dups` while reading other fields.

coverage: Explain why we temporarily steal pending_dups

7aa1b83

Zalathar force-pushed the spans branch from 0f552df to 7aa1b83 Compare October 16, 2023 10:07

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-review Status: Awaiting review from the assignee but also interested parties. labels Oct 16, 2023

GuillaumeGomez mentioned this pull request Oct 16, 2023

Rollup of 6 pull requests #116820

Merged

bors merged commit 581f88d into rust-lang:master Oct 17, 2023
11 checks passed

rustbot added this to the 1.75.0 milestone Oct 17, 2023

Zalathar deleted the spans branch October 17, 2023 01:19

Veykril mentioned this pull request Oct 17, 2023

Pull upstream master 2023 10 17 ferrocene/ferrocene#54

Merged

Zalathar mentioned this pull request Nov 11, 2023

Malformed coverage data with a no_mangle function #117788

Closed

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coverage: Several small cleanups in `spans` #116754

coverage: Several small cleanups in `spans` #116754

Zalathar commented Oct 15, 2023

rustbot commented Oct 15, 2023

rustbot commented Oct 15, 2023

Zalathar commented Oct 15, 2023

Zalathar commented Oct 15, 2023

bors commented Oct 15, 2023

oli-obk Oct 16, 2023

Zalathar Oct 16, 2023

Zalathar Oct 16, 2023

oli-obk Oct 16, 2023

Zalathar commented Oct 16, 2023

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oli-obk commented Oct 16, 2023

bors commented Oct 16, 2023

coverage: Several small cleanups in spans #116754

coverage: Several small cleanups in spans #116754

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bors commented Oct 16, 2023

coverage: Several small cleanups in `spans` #116754

coverage: Several small cleanups in `spans` #116754