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[5.7] Fix infinite loop and scalar matching in grapheme mode + scalar matching optimizations #569

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Merged
merged 2 commits into from
Jul 21, 2022
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[5.7] Fix infinite loop and scalar matching in grapheme mode + scalar matching optimizations #569

merged 2 commits into from
Jul 21, 2022

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rctcwyvrn
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@rctcwyvrn rctcwyvrn commented Jul 12, 2022 •
edited by hamishknight
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Cherry pick of #525 (which includes #565) and #560

rdar://97394951

@rctcwyvrn rctcwyvrn requested a review from stephentyrone July 12, 2022 18:55
This was referenced Jul 13, 2022
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  • Explanation: Fixes UnicodeScalar matching behavior in the DSL, such that we do not consume part of a grapheme. Additionally fixes the matching engine such that we avoid creating an infinite loop when attempting to match a quantification of a potentially empty match.

  • Scope: Affects the runtime matching behavior of regex literals and DSLs.

  • Radar: rdar://97394951

  • Risk: Low/Medium – This does require making quite a few changes to the machine engine logic, however many test cases have been added to ensure correctness.

  • Testing: Added test cases to the repo.

  • Reviewer: @milseman

@hamishknight hamishknight added the r5.7 5.7 Release Cherry Picks label Jul 21, 2022
rctcwyvrn added 2 commits July 21, 2022 23:16
@rctcwyvrn @hamishknight
Break out of quantification loop if there is no forward progress (swi…
bf08402 
…ftlang#560)

This fixes infinite loops when we loop over an internal node that does not have any forward progress. Also included is an optimization to only emit the check/break instructions if we have a case that might result in an infinite loop (possibly non-progressing inner node + unlimited quantification)
@rctcwyvrn @hamishknight
Optimize matching to match on scalar values when possible (swiftlang#525
5f5848e 
)

- Adds new instructions for matching characters and scalars case insensitively
- Compiles ascii character matches into the faster scalar match instructions even in grapheme semantic mode
- Optimizes out unnecessary runtime grapheme boundary checks for all ascii strings
- Also includes fixes to scalar matching in grapheme semantic mode (swiftlang#565)
@hamishknight hamishknight force-pushed the uhoh-infinite-loop-5.7 branch from 3235ef3 to 5f5848e Compare July 21, 2022 22:22
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@swift-ci please test

@hamishknight hamishknight merged commit 7aedd69 into swiftlang:swift/release/5.7 Jul 21, 2022
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@stephentyrone stephentyrone stephentyrone approved these changes

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