Reflection: correct conformance table iteration #41221
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Adjust the iteration of the conformance table to match the current data structure layout. `MapData` is a view into the `ConformanceState`: ~~~ [+0x00] Cache [Type: swift::ConcurrentReadableHashMap<ConformaanceCacheEntry, swift::StaticMutex>] [+0x28] SectionsToScan [Type: swift::ConcurrentReadableArray<ConformanceSection>] [+0x50] scanSectionsBackwards [Type: bool] ~~~ `Cache` itself is a structure: ~~~ [+0x00] ReaderCount [Type: std::atomic<uint32_t>] [+0x04] ElementCount [Type: std::atomic<uint32_t>] [+0x08] Elements [Type: std::atomic<swift::ConcurrentReadableHashMap<ConformanceCacheEntry, swift::staticMutex>::ElementStorage *>] ~~~ The `ElementStorage` backing `Elements` actually looks like: ~~~ [+0x00] Capacity [Type: uint32_t] [+0x08] Elem [Typwe: ConformanceCacheEntry] ~~~ The `Capacity` field will be pointer aligned (a previous change has changed this to be explicitly pointer sized bit-sliced). However, we would previously fail to accomodate the `Capacity` field, and read the contents shifted by the size of `Capacity`. This repairs the iteration off the `ConformanceCache`.
|
CC: @tbkka |
mikeash
approved these changes
Feb 5, 2022
|
@swift-ci please test |
|
Build failed |
|
@swift-ci please test Linux platform |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Adjust the iteration of the conformance table to match the current data structure layout.
MapDatais a view into theConformanceState:Cacheitself is a structure:The
ElementStoragebackingElementsactually looks like:The
Capacityfield will be pointer aligned (a previous change has changed thisto be explicitly pointer sized bit-sliced). However, we would previously fail
to accomodate the
Capacityfield, and read the contents shifted by the size ofCapacity. This repairs the iteration off theConformanceCache.Replace this paragraph with a description of your changes and rationale. Provide links to external references/discussions if appropriate.
Resolves SR-NNNN.