Introduce a custom availability domain for UnicodeNormalization #85324
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
Custom availability serialization is based on serializing the underlying declaration that describes the availability domain. Those don't exist yet, so conjure up a VarDecl that we use just for the name. When deserializing based on one of these declarations, do a lookup into the module. This is quite gross, but lets us do more experimentation.
Tag the C functions used by the standard library for Unicode normalization as being part of a new availability domain called "UnicodeNormalization". Mark anything else that (transitively) depends on those functions as requiring UnicodeNormalization, so that we get the full surface area of the standard library that somehow depends on the Unicode data tables (for normalization). This availability domain is always available in non-Embedded Swift. In Embedded Swift, this availability domain is optional: if it's enabled, one needs to link against the swiftUnicodeDataTables library. If it's disabled, the compiler will have rejected any code that depends on the Unicode tables. This provides better diagnostic experience for Embedded Swift where one does not have to work backwards from a linker failure to determine where the Unicode normalization tables occur. Part of rdar://151212706.
DougGregor
requested review from
a team,
Xazax-hun,
artemcm,
hnrklssn and
tshortli
as code owners
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.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.
Tag the C functions used by the standard library for Unicode
normalization as being part of a new availability domain called
"UnicodeNormalization". Mark anything else that (transitively) depends
on those functions as requiring UnicodeNormalization, so that we get
the full surface area of the standard library that somehow depends on
the Unicode data tables (for normalization).
This availability domain is always available in non-Embedded Swift. In
Embedded Swift, this availability domain is optional: if it's enabled,
one needs to link against the swiftUnicodeDataTables library. If it's
disabled, the compiler will have rejected any code that depends on the
Unicode tables. This provides better diagnostic experience for Embedded
Swift where one does not have to work backwards from a linker failure
to determine where the Unicode normalization tables occur.
Part of rdar://151212706.