Functions like withUnsafeBufferPointer are, by themselves, safe to
call. It's only the operations on the unsafe pointers passed into the
closure that are the safety issue.
This was the intent spelled out in SE-0458 but was not fully realized
in the library.
Fixes rdar://174519372.
This isn't a "complete" port of the standard library for embedded Swift, but
something that should serve as a starting point for further iterations on the
stdlib.
- General CMake logic for building a library as ".swiftmodule only" (ONLY_SWIFTMODULE).
- CMake logic in stdlib/public/core/CMakeLists.txt to start building the embedded stdlib for a handful of hardcoded target triples.
- Lots of annotations throughout the standard library to make types, functions, protocols unavailable in embedded Swift (@_unavailableInEmbedded).
- Mainly this is about stdlib functionality that relies on existentials, type erasure, metatypes, reflection, string interpolations.
- We rely on function body removal of unavailable functions to eliminate the actual problematic SIL code (existentials).
- Many .swift files are not included in the compilation of embedded stdlib at all, to simplify the scope of the annotations.
- EmbeddedStubs.swift is used to stub out (as unavailable and fatalError'd) the missing functionality.
This let the optimizer generate efficient code for generic array loops (note that generic functions are not inlined by default).
Note that the same change is not done for `Array` because this might increase code size due to Array's bridging code.
rdar://108746069
Types that have "value semantics" should not have lexical lifetimes.
Value types are not expected to have custom deinits. Are not expected to
expose unsafe interior pointers. And cannot have weak references because
they are structs. Therefore, deinitialization barriers are irrelevant.
rdar://107076869
Cleanup code in _modify accessors will only run reliably if it is put in a defer statement.
(Statements that follow the `yield` aren’t executed if the yielded-to code throws an error.)
* [stdlib] Deprecate MutableCollection._withUnsafeMutableBufferPointerIfSupported
In Swift 5.0, [SE-0237] introduced the public `MutableCollection.withContiguousMutableStorageIfAvailable` method. It’s time we migrated off the old, underscored variant and deprecated it.
The default `MutableCollection.sort` and `.partition(by:)` implementations are currently calling this hidden method rather than the documented interface, preventing custom Collection implementations from achieving good performance, even if they have contiguous storage.
[SE-0237]: https://github.com/apple/swift-evolution/blob/master/proposals/0237-contiguous-collection.md
* [test] Update tests for stdlib behavior changes
* Update stdlib/private/StdlibCollectionUnittest/CheckMutableCollectionType.swift
Co-authored-by: Nate Cook <natecook@apple.com>
* Update stdlib/private/StdlibCollectionUnittest/CheckMutableCollectionType.swift
Co-authored-by: Nate Cook <natecook@apple.com>
* Apply suggestions from code review
Co-authored-by: Nate Cook <natecook@apple.com>
* [test] LoggingMutableCollection: Fix logging targets
* [stdlib] Fix warning by restoring original workaround
Co-authored-by: Nate Cook <natecook@apple.com>
Introduce checking of ConcurrentValue conformances:
- For structs, check that each stored property conforms to ConcurrentValue
- For enums, check that each associated value conforms to ConcurrentValue
- For classes, check that each stored property is immutable and conforms
to ConcurrentValue
Because all of the stored properties / associated values need to be
visible for this check to work, limit ConcurrentValue conformances to
be in the same source file as the type definition.
This checking can be disabled by conforming to a new marker protocol,
UnsafeConcurrentValue, that refines ConcurrentValue.
UnsafeConcurrentValue otherwise his no specific meaning. This allows
both "I know what I'm doing" for types that manage concurrent access
themselves as well as enabling retroactive conformance, both of which
are fundamentally unsafe but also quite necessary.
The bulk of this change ended up being to the standard library, because
all conformances of standard library types to the ConcurrentValue
protocol needed to be sunk down into the standard library so they
would benefit from the checking above. There were numerous little
mistakes in the initial pass through the stsandard library types that
have now been corrected.
Guillaume Lessard
Doug Gregor
Rick van Voorden
Meghana Gupta
Artem Chikin
Meghana Gupta
Allan Shortlidge
Hamish Knight
David Smith
Kuba Mracek
Lucy Satheesan
Erik Eckstein
Nate Chandler
Karoy Lorentey
Matt Zanchelli