Create a _StringRepresentation struct to standardize internal testing
on. Internalize much of _StringGuts, except for some SPI hacks, and
update tests to use _StringRepresentation.
* Update std lib to Swift 5.0
* Disable Unicode.* warnings for now
* Slow path to resiliently handle the case where an unknown rounding rule is passed
* Remove resilience from Encoding/DecodingError (which should only happen on slow paths anyway)
* internal typealiases now need @usableFromInline
* Force inlining on Array._owner.get
Add some fast paths to String.init(decoding:as:) for inputs of
contiguously stored UTF-8 code units. Dramatically speeds up creation
when the String happens to be ASCII and we can form more small
strings.
@effects is too low a level, and not meant for general usage outside
the standard library. Therefore it deserves to be underscored like
other such attributes.
The main part of this is to rewrite the small string literal-constructor to work with values (= shifting bytes) instead of setting bytes in memory.
This allows the compiler to fold away everything and end up with the optimal code for small string literals.
Drop append-related @inlinable annotations for String, StringGuts,
StringStorage, and the Views. Drop several for larger operations, such
as case conversion. Drop as many as we can from StringGuts for now.
Switch StringObject and StringGuts from opaquely storing tagged cocoa
strings into storing small strings. Plumb small string support
throughout the standard library's routines.
Streamline internal String creation. Previously, everything funneled
into a single generic function, however, every single call of the
generic funnel had relevant specific information that could be used
for a more efficient algorithm.
In preparation for efficiently forming small strings, refactor this
logic into a handful of more specialized subroutines to preserve more
specific information from the callers.
Adds some comments for sections of code that doesn't adopt the
visitation pattern, or have inefficiencies discovered as part of this
work. Additionally, mutating methods generally do not use the visitor
scheme.
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.
In preparation for small strings optimizations, bifurcate StringGuts's
inits to denote when the caller is choosing to skip any checks for is
small. In the majority of cases, the caller has more local information
to guide the decision.
Adds todos and comments as well:
* TODO(SSO) denotes any task that should be done simultaneously with
the introduction of small strings.
* TODO(TODO: JIRA) denotes tasks that should eventually happen
later (and will have corresponding JIRAs filed for).
* TODO(Comparison) denotes tasks when the new string comparison
lands.
- Adding docs for unbounded ranges
- Filling in missing docs for range-expression subscripts
- Equality operators for arrays
- Fix issues with range discussions
- Fill in missing integer docs
This is a temporary workaround for some situations where the empty
singleton is not being formed correctly (and this seems to be highly
configuration dependent). Work around that for now for also checking
for empty non-storage-backed Strings.
This is probably too expensive a check for us to do long-term, but it
works for now.
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.
- 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
