The assertions here are based around the idea that `std::atomic` is
trivially constructible which is not a guarantee that the standard fully
provides. The default initialization of the `std::atomic` type may
leave it in an undetermined state. These were caught using the Visual
C++ preview runtime.
Ideally, the object constructor would use a placement new operator.
However, prior to C++17, the C++ standard mandated that there be a
NULL pointer check in the placement new operator. This is something
which is no longer the case with C++17. Switch to the placement new
operator for C++17 and newer and enable that codepath for Windows as
well (which seemingly elides the null-pointer check with clang-cl).
- Don’t expose the raw execution seed to _rawHashValue.
- Change the type of _rawHashValue’s seed from (UInt64,UInt64) to a single Int. Working with a pair of UInt64s is unwieldy, and overkill in practice. Int as a seed also integrates nicely with Int as a hash value.
- Remove _HasherCore._generateSeed(). Instead, simply call finalize() on a copy of the hasher to get a seed suitable for _rawHashValue.
- Update Set and Dictionary to store a single Int as the seed value.
Note that this doesn’t affect the core hasher, which still mixes in the actual 128-bit execution seed during its initialization. To reduce the potential of confusion, use the name “rawSeed” to refer to an actual 128-bit seed value.
- Use _HashTable to unify low-level hashing operations across Set and Dictionary.
- Store the capacity directly inside the storage header. This allows the maximum load factor to be controlled by non-inlinable code.
- Introduce a dedicated class for the empty singleton.
- Add _BridgingHashBuffer, a standalone flat hash buffer for use in deferred bridging. Use it to eliminate the need to support non-hashable storage/wrapper variants and to improve memory use in cases where Key or Value are verbatim bridged.
- Eliminate the “TypedNative*Storage” class and _NativeSet/_NativeDictionary’s support for non-hashable keys.
- Rename storage classes as follows:
_RawNativeSetStorage ⟹ _RawSetStorage
_RawNativeDictionaryStorage ⟹ _RawDictionaryStorage
_TypedNativeSetStorage ⟹ (removed)
_TypedNativeDictionaryStorage ⟹ (removed)
_HashableTypedNativeSetStorage ⟹ _SetStorage
_HashableTypedNativeDictionaryStorage ⟹ _DictionaryStorage
The new names make it obvious which ivar layout is in use.
This allows us to move the empty NSSet/NSDictionary overrides out of the root storage class; they don’t really belong there. More importantly, it makes empty sets/dictionaries super obvious to lldb and other runtime tools.
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.
- Hash seed randomization can now be disabled by defining the SWIFT_DETERMINISTIC_HASHING environment value with a value of "1".
- The random hash seed is now generated using arc4random, where available. On platforms where it isn't, don't construct std::random_device twice.
- _Hasher._secretKey is renamed _Hashing._seed, with no setter.
- _Hasher._isDeterministic is a new property exposing whether we're running with non-random hashes. (Set/Dictionary will need this information to decide if they're allowed to use per-instance seeding.)
I had optimistically written the code here optimistically hoping #7837 would land in time for me to merge, but that didn't happen, so adjust some things to match the current 12-byte object header size on 32-bit, and introduce some ABI constants for the expected 32- and 64-bit object header sizes we can assert against so that we have some robustness when it eventually changes again. Implements rdar://problem/31768303.
Provides a new fallback for Process arguments for those instances where we do
not own main (e.g. Frameworks, Objective-C owns main.m or main.c, etc.). This
includes a number of platform-specific specializations of argument grabbing
logic and a new thread-safe interface to Process.unsafeArgv.
main() | _NSGetArgc/_NSGetArgv | /proc/self/cmdline | __argc/__argv
--------|--------------------------|------------------------|---------------
Scripts | OS X, iOS, tvOS, watchOS | Linux, FreeBSD, Cygwin | Windows
For interpreted Swift where we must filter out the arguments we now do so by
loading the standard library and calling into new SPI to override the arguments
that would have been grabbed by the runtime. This implementation completely
subsumes the use of the entry point '_stdlib_didEnterMain' and it will be
removed in a future commit.
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
