[stdlib] Remove obsolete hashing interfaces

(cherry picked from commit 1e1f6b8)

Author: lorentey

stdlib/public/core/Hashing.swift

@@ -11,181 +11,8 @@
 //===----------------------------------------------------------------------===//
 
 //
-// This file implements helpers for constructing non-cryptographic hash
-// functions.
+// This file implements helpers for hashing collections.
 //
-// This code was ported from LLVM's ADT/Hashing.h.
-//
-// Currently the algorithm is based on CityHash, but this is an implementation
-// detail.  Even more, there are facilities to mix in a per-execution seed to
-// ensure that hash values differ between executions.
-//
-
-@_frozen // FIXME(sil-serialize-all)
-public // @testable
-enum _HashingDetail {
-
-  // FIXME(hasher): Remove
-  @inlinable // FIXME(sil-serialize-all)
-  @_transparent
-  internal static func getExecutionSeed() -> UInt64 {
-    // FIXME: This needs to be a per-execution seed. This is just a placeholder
-    // implementation.
-    return 0xff51afd7ed558ccd
-  }
-
-  // FIXME(hasher): Remove
-  @inlinable // FIXME(sil-serialize-all)
-  @_transparent
-  internal static func hash16Bytes(_ low: UInt64, _ high: UInt64) -> UInt64 {
-    // Murmur-inspired hashing.
-    let mul: UInt64 = 0x9ddfea08eb382d69
-    var a: UInt64 = (low ^ high) &* mul
-    a ^= (a >> 47)
-    var b: UInt64 = (high ^ a) &* mul
-    b ^= (b >> 47)
-    b = b &* mul
-    return b
-  }
-}
-
-//
-// API functions.
-//
-
-//
-// _mix*() functions all have type (T) -> T.  These functions don't compress
-// their inputs and just exhibit avalanche effect.
-//
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixUInt32(_ value: UInt32) -> UInt32 {
-  // Zero-extend to 64 bits, hash, select 32 bits from the hash.
-  //
-  // NOTE: this differs from LLVM's implementation, which selects the lower
-  // 32 bits.  According to the statistical tests, the 3 lowest bits have
-  // weaker avalanche properties.
-  let extendedValue = UInt64(value)
-  let extendedResult = _mixUInt64(extendedValue)
-  return UInt32((extendedResult >> 3) & 0xffff_ffff)
-}
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixInt32(_ value: Int32) -> Int32 {
-  return Int32(bitPattern: _mixUInt32(UInt32(bitPattern: value)))
-}
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixUInt64(_ value: UInt64) -> UInt64 {
-  // Similar to hash_4to8_bytes but using a seed instead of length.
-  let seed: UInt64 = _HashingDetail.getExecutionSeed()
-  let low: UInt64 = value & 0xffff_ffff
-  let high: UInt64 = value >> 32
-  return _HashingDetail.hash16Bytes(seed &+ (low << 3), high)
-}
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixInt64(_ value: Int64) -> Int64 {
-  return Int64(bitPattern: _mixUInt64(UInt64(bitPattern: value)))
-}
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixUInt(_ value: UInt) -> UInt {
-#if arch(i386) || arch(arm)
-  return UInt(_mixUInt32(UInt32(value)))
-#elseif arch(x86_64) || arch(arm64) || arch(powerpc64) || arch(powerpc64le) || arch(s390x)
-  return UInt(_mixUInt64(UInt64(value)))
-#endif
-}
-
-// FIXME(hasher): Remove
-@inlinable // FIXME(sil-serialize-all)
-@_transparent
-public // @testable
-func _mixInt(_ value: Int) -> Int {
-#if arch(i386) || arch(arm)
-  return Int(_mixInt32(Int32(value)))
-#elseif arch(x86_64) || arch(arm64) || arch(powerpc64) || arch(powerpc64le) || arch(s390x)
-  return Int(_mixInt64(Int64(value)))
-#endif
-}
-
-/// Returns a new value that combines the two given hash values.
-///
-/// Combining is performed using [a hash function][ref] described by T.C. Hoad
-/// and J. Zobel, which is also adopted in the Boost C++ libraries.
-///
-/// This function is used by synthesized implementations of `hashValue` to
-/// combine the hash values of individual `struct` fields and associated values
-/// of `enum`s. It is factored out into a standard library function so that the
-/// specific hashing logic can be refined without requiring major changes to the
-/// code that creates the synthesized AST nodes.
-///
-/// [ref]: https://pdfs.semanticscholar.org/03bf/7be88e88ba047c6ab28036d0f28510299226.pdf
-@_transparent
-public // @testable
-func _combineHashValues(_ firstValue: Int, _ secondValue: Int) -> Int {
-  // Use a magic number based on the golden ratio
-  // (0x1.9e3779b97f4a7c15f39cc0605cedc8341082276bf3a27251f86c6a11d0c18e95p0).
-#if arch(i386) || arch(arm)
-  let magic = 0x9e3779b9 as UInt
-#elseif arch(x86_64) || arch(arm64) || arch(powerpc64) || arch(powerpc64le) || arch(s390x)
-  let magic = 0x9e3779b97f4a7c15 as UInt
-#endif
-  var x = UInt(bitPattern: firstValue)
-  x ^= UInt(bitPattern: secondValue) &+ magic &+ (x &<< 6) &+ (x &>> 2)
-  return Int(bitPattern: x)
-}
-
-// FIXME(hasher): This hasher emulates Swift 4.1 hashValues. It is purely for
-// benchmarking; to be removed.
-internal struct _LegacyHasherCore: _HasherCore {
-  internal var _hash: Int
-
-  @inline(__always)
-  internal init(seed: (UInt64, UInt64) = (0, 0)) { // seed is ignored
-    _hash = 0
-  }
-
-  @inline(__always)
-  internal mutating func compress(_ value: UInt64) {
-    let value = (UInt64.bitWidth > Int.bitWidth
-      ? Int(truncatingIfNeeded: value ^ (value &>> 32))
-      : Int(truncatingIfNeeded: value))
-    _hash = (_hash == 0 ? value : _combineHashValues(_hash, value))
-  }
-
-  @inline(__always)
-  internal mutating func finalize(tailAndByteCount: UInt64) -> UInt64 {
-    let count = (tailAndByteCount &>> 56) & 7
-    if count > 0 {
-      compress(tailAndByteCount & ((1 &<< (count &<< 3)) - 1))
-    }
-    return UInt64(
-      _truncatingBits: UInt(bitPattern: _mixInt(_hash))._lowWord)
-  }
-
-  @inline(__always)
-  func _generateSeed() -> (UInt64, UInt64) {
-    return (0, 0)
-  }
-}
-
 
 /// This protocol is only used for compile-time checks that
 /// every buffer type implements all required operations.

validation-test/compiler_crashers_2_fixed/0123-rdar31164540.swift

@@ -38,6 +38,10 @@ internal func _abstract(
 #endif
 }
 
+internal func _mixInt(_ value: Int) -> Int {
+  return value.hashValue
+}
+
 // MARK: Type-erased abstract base classes
 
 public class AnyKeyPath: Hashable {