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coverage: Hoist the removal of unwanted macro expansion spans

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This commit is contained in:
Zalathar 2023-12-21 23:03:45 +11:00
parent df0df5256b
commit cd3a9760e4
2 changed files with 27 additions and 26 deletions
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29
compiler/rustc_mir_transform/src/coverage/spans.rs
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@ -251,32 +251,9 @@ impl<'a> CoverageSpansGenerator<'a> {
} else if curr.is_closure {
self.carve_out_span_for_closure();
} else if self.prev_original_span == curr.span {
// Note that this compares the new (`curr`) span to `prev_original_span`.
// In this branch, the actual span byte range of `prev_original_span` is not
// important. What is important is knowing whether the new `curr` span was
// **originally** the same as the original span of `prev()`. The original spans
// reflect their original sort order, and for equal spans, conveys a partial
// ordering based on CFG dominator priority.
if prev.visible_macro.is_some() && curr.visible_macro.is_some() {
// Macros that expand to include branching (such as
// `assert_eq!()`, `assert_ne!()`, `info!()`, `debug!()`, or
// `trace!()`) typically generate callee spans with identical
// ranges (typically the full span of the macro) for all
// `BasicBlocks`. This makes it impossible to distinguish
// the condition (`if val1 != val2`) from the optional
// branched statements (such as the call to `panic!()` on
// assert failure). In this case it is better (or less
// worse) to drop the optional branch bcbs and keep the
// non-conditional statements, to count when reached.
debug!(
" curr and prev are part of a macro expansion, and curr has the same span \
as prev, but is in a different bcb. Drop curr and keep prev for next iter. \
prev={prev:?}",
);
self.take_curr(); // Discards curr.
} else {
self.update_pending_dups();
}
// `prev` and `curr` have the same span, or would have had the
// same span before `prev` was modified by other spans.
self.update_pending_dups();
} else {
self.cutoff_prev_at_overlapping_curr();
self.maybe_push_macro_name_span();