Switch StringObject and StringGuts from opaquely storing tagged cocoa
strings into storing small strings. Plumb small string support
throughout the standard library's routines.
Use the visitor pattern in most of the opaque-by-hand call
sites. Inspecting the compiler output does not show excessive and
unanticipated ARC, but there may need to be further tweaks.
One downside of the visitor pattern as written is that there's extra
shuffling around of registers for the closure CC. Hopefully this will
also be fixed soon.
Stop inlining _asOpaque into user code. Inlining it bloats user code
as there's a bit-test-and-branch to a block containing the _asOpaque
call, followed up some operations to e.g. manipulate the range or
re-align the calling convention, etc., followed by a final branch to
opaque stdlib code.
Instead, branch directly into opaque stdlib code. In theory, this
means that supporting all opaque patterns can be done with minimal
bloat. On ARM, this is a single tbnz instruction.
Deprecated the `PlaygroundQuickLook` enum and `CustomPlaygroundQuickLookable`
protocol. These are being targeted for removal in Swift 5, so we want to
unconditionally deprecate them now to encourage use of
`CustomPlaygroundDisplayConvertible` instead.
This commit includes deprecated the various `CustomPlaygroundQuickLookable`
conformances across the standard library and overlay libraries.
Include the initial implementation of _StringGuts, a 2-word
replacement for _LegacyStringCore. 64-bit Darwin supported, 32-bit and
Linux support in subsequent commits.
In grand LLVM tradition, the first step to redesigning _StringCore is
to first rename it to _LegacyStringCore. Subsequent commits will
introduce the replacement, and eventually all uses of the old one will
be moved to the new one.
NFC.
* Eradicate IndexDistance associated type, replacing with Int everywhere
* Consistently use Int for ExistentialCollection’s IndexDistance type.
* Fix test for IndexDistance removal
* Remove a handful of no-longer-needed explicit types
* Add compatibility shims for non-Int index distances
* Test compatibility shim
* Move IndexDistance typealias into the Collection protocol
* Unify the capitalization across all user-visible error messages (fatal errors, assertion failures, precondition failures) produced by the runtime, standard library and the compiler.
* Update some more tests to the new expectations.
- Update NSRange -> Range guidance
- Fix example in Optional
- Improve RangeExpression docs
- Fix issue in UnsafeRawBufferPointer.initializeMemory
- Code point -> scalar value most places
- Reposition the dot above the scripty `i'
- Fix ExpressibleByArrayLiteral code sample
This necessary for ensuring the property that String doesn't keep
inaccessible memory alive. For example, before this change,
String(s.dropFirst().unicodeScalars)
would compile and produce a String that owned inaccessible memory.
Now it no longer compiles.
String's view's SubSequences are the same as the Substring's
view. E.g. String.UnicodeScalarView.SubSequence is
Substring.UnicodeScalarView.
New compatibility inits added, to work around the fact that many
previously failable initializers are now non-failable.
This is a step along the way toward handling backward-compatiblity of UTF8View
slicing and preventing inadvertent creation of String instances that keep
inaccessible memory alive.
I failed to merge the upstream changes to swift-corelibs-foundation at the same
time as I merged that #9806, and it broke on linux. Going to get it right this
time.
