The `__future__` we relied on is now, where the 3 specific things are
all included [since Python 3.0](https://docs.python.org/3/library/__future__.html):
* absolute_import
* print_function
* unicode_literals
* division
These import statements are no-ops and are no longer necessary.
Commit the platform definition and build script work necessary to
cross-compile for arm64_32.
arm64_32 is a variant of AARCH64 that supports an ILP32 architecture.
Fix Hashable conformance of standard integer types so that the number of bits they feed into hasher is exactly Self.bitWidth.
This was intended to be part of SE-0206. However, it would have introduced additional issues with AnyHashable. The custom AnyHashable representations introduced in the previous commit unify hashing for numeric types, eliminating the problem.
Newly internal declarations include Hasher._seed and the integer overloads of Hasher._combine(_:), as well as _SipHash13 and _SipHash24.
Unify the interfaces of these SipHash testing structs with Hasher. Update SipHash test to cover Hasher, too.
Add @usableFromInline to all newly internal stuff. In addition to its normal use, it also enables white box testing; compile tests that need to use these declarations with -disable-access-control.
Beyond switching hashing algorithms, this also enables per-execution hash seeds, fulfilling a long-standing prophecy in Hashable’s documentation.
To reduce the possibility of random test failures, StdlibUnittest’s TestSuite overrides the random hash seed on initialization.
rdar://problem/24109692
rdar://problem/35052153
Introduce _Hasher, representing an opaque hash compression function.
Add the method _hash(into:) as a Hashable requirement, decoupling the choice of hash function from Hashable's implementation. The default implementation of _hash(into:) has a default implementation that simply feeds hashValue to the hasher.
Add _hash(into:) implementations for the default integer types. Note that Int.hashValue does not return self anymore.
Add struct _LegacyHasher, emulating Swift 4.1 hashes in the new interface.
`FixedPoint.swift.gyb` generates a massive amount of assertions:
one for each `Int` type (such as `UInt8` and `Int64`) as a source,
to one of each `Int` type as a destination, for each of 27 bit
patterns. By my math that's 8 * 8 * 27 == 1728 assertions.
As a result, when one of those assertions fails, it's difficult to
tell what went wrong.
Split each assertion into its own test case. This makes the test
take a little longer to run, but it produces much more valuable
output when it fails.
This patch adds powerpc64le Linux support. While the patch also adds
the matching powerpc64 bits, there are endian issues that need to be
sorted out.
The PowerPC LLVM changes for the swift ABI (eg returning three element
non-homogeneous aggregates) are still in the works, but a simple LLVM
fix to allow those aggregates results in swift passing all but 8
test cases.
