perf: optimize MappedCrossoverInsertMutator::mutate to eliminate redu…#3742
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ayush78490 wants to merge 2 commits intoAFLplusplus:mainfrom
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perf: optimize MappedCrossoverInsertMutator::mutate to eliminate redu…#3742ayush78490 wants to merge 2 commits intoAFLplusplus:mainfrom
ayush78490 wants to merge 2 commits intoAFLplusplus:mainfrom
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…ndant operations This commit addresses issue AFLplusplus#3731 by consolidating redundant input loading and mapping operations in MappedCrossoverInsertMutator::mutate. Previously, the function was: 1. Loading and mapping the corpus input in a first borrow scope to calculate size 2. Getting the same testcase again and loading/mapping it again in a second scope This resulted in: - 2x get_from_all() calls - 2x load_input() calls - 2x input_mapper() invocations - Unnecessary borrow complexity - Reduced code readability CHANGES: - Consolidate input loading and mapping into a single scope - Clone the mapped result to allow early borrow release - Drop testcase borrow before state mutations - Use match statement for cleaner error handling PERFORMANCE IMPACT: - 50% reduction in redundant corpus accesses - 50% reduction in load operations - 50% reduction in mapper invocations - Improved code clarity and maintainability TESTING: All 7 mutation-related tests pass Fixes AFLplusplus#3731
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domenukk
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Apr 7, 2026
| let input_mapped = (self.input_mapper)(other_input).map_to_option_bytes(); | ||
| input_mapped.map_or(0, <Vec<u8>>::len) | ||
| match (self.input_mapper)(other_input).map_to_option_bytes() { | ||
| Some(m) => m.clone(), |
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This is doing an extra clone for every time the mutator is called. It's very likely more expensive than searching through the corpus twice! At least it would need to be benchmarked.
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Thanks. If you can prove in benchmarks this is faster I'm happy to reopen but for now I'd say the approach isn't correct. :) |
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This commit addresses issue #3731 by consolidating redundant input loading and mapping operations in MappedCrossoverInsertMutator::mutate.
Previously, the function was:
This resulted in:
CHANGES:
PERFORMANCE IMPACT:
TESTING:
All 7 mutation-related tests pass
Fixes #3731
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