* Add partial range subscripts to _UnmanagedOpaqueString
* Use SipHash13+_NormalizedCodeUnitIterator for String hashes on all platforms
* Remove unecessary collation algorithm shims
* Pass the buffer to the SipHasher for ASCII
* Hash the ascii parts of UTF16 strings the same way we hash pure ascii strings
* De-dupe some code that can be shared between _UnmanagedOpaqueString and _UnmanagedString<UInt16>
* ASCII strings now hash consistently for in hashASCII() and hashUTF16()
* Fix zalgo comparison regression
* Use hasher
* Fix crash when appending to an empty _FixedArray
* Compact ASCII characters into a single UInt64 for hashing
* String: Switch to _hash(into:)-based hashing
This should speed up String hashing quite a bit, as doing it through hashValue involves two rounds of SipHash nested in each other.
* Remove obsolete workaround for ARC traffic
* Ditch _FixedArray<UInt8> in favor of _UIntBuffer<UInt64, UInt8>
* Bad rebase remnants
* Fix failing benchmarks
* michael's feedback
* clarify the comment about nul-terminated string hashes
I was trying to make the entry-delegation thing do *way* too much.
Just give the entry access to the lock/queue and introduce subclasses
which simplify most of the work.
Also, fix some bad reasoning around the attempts to avoid acquiring
locks in the absence of waiters. It really is always necessary to
acquire the lock when notifying; waiters cannot atomically set the
has-waiters flag and wait, so we have to protect against the
possibility that we notify before they can wait.
* Cleanup tgmath wrappers.
- Remove special-case gyb logic for lgamma on Darwin; the symbols we need are always present, even if not visible in the headers, so we only need a prototype.
- Add some deprecations for symbols that have direct stdlib analogues.
- Make some operations generic on [Binary]FloatingPoint, where they can map to the protocols instead of calling libm.
- Mark ldexp(Float/Double) renamed to scalbn; for binary formats these are identical functions, and we don't really want to use these names for hypothetical future Decimal support, as they're not Swifty.
* Change the RemoteMirror API to have extensible data layout callback
* Use DLQ_Get prefix on DataLayoutQueryType enum values
* Simplify MemoryReaderImpl and synthesize minimalDataLayoutQueryFunction
This allows them to be used in generic arguments for NSArray et al.
We already do this for the ones that wrap bridged values (like
NSString/String), but failed to do it for objects that /weren't/
bridged to Swift values (class instances and protocol compositions),
or for Error-which-is-special.
In addition to this being a sensible thing to do, /not/ doing this led
to IRGen getting very confused (i.e. crashing) when we imported a
Objective-C protocol that actually used an NS_TYPED_ENUM in this way.
(We actually shouldn't be using Swift's IRGen logic to emit protocol
descriptors for imported protocols at all, because it's possible we
weren't able to import all the requirements. But that's a separate
issue.)
https://bugs.swift.org/browse/SR-6844
It looks like we exposed a bunch of Metal APIs to Swift 3 that we
didn't mean to; at this point it would be a source-breaking change to
hide them. Oops.
This is done by xoring the base address of the hash table storage to the hash seed.
In deterministic mode, we perturb the seed by the bucket count instead, so that we ordering within hashed collections remains repeatable (as long as the capacity doesn't change).
Fixes https://bugs.swift.org/browse/SR-3268
Having a single initializer function lets us not set a randomized seed in deterministic mode, slightly simplifying the stdlib.
Set related stdlib properties to be always inlined.
StringStorage tried to adopt the visitor pattern, but it regressed
benchmarks too much. We'd like to come up with a mutation story
anyways, and StringStorage was sort of cheating that by being a class.
Restores perf-regressions of Join etc.
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.
Add a visitor-like function which will inspect the bitpattern of
_StringGuts and dispatch to the appropriate mechanism. This allows us
to keep the core usage pattern in one spot, and tweak the branching
scheme as the ABI finalizes.
It also reduces the bug surface area by allowing us to maintain
resilience in the visitor, instead of by-hand at every use site. It
also prevents expression-drift, which the by-hand opaque pattern is
susceptible to.
Current implementation is very carefully written to avoid excess
ARC. Uses need to be very careful about not capturing, or else there
will be non-trivial closure contexts and performance will blow
up. Both of these aspects will hopefully 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.
