swift 6.0+ performance tweaks 3x-6x (#9067)

* start/stop measurements

* tweaks

* add 6.0 annotations

* remove some inlines

* address feedback

* address wasi + let

* adopt flex buffers

* flex buffers benchmarks

swift/Sources/Common/Scalar.swift

@@ -28,7 +28,7 @@ public let FileIdLength = 4
 /// Protocol that All Scalars should conform to
 ///
 /// Scalar is used to conform all the numbers that can be represented in a FlatBuffer. It's used to write/read from the buffer.
-public protocol Scalar: Equatable {
+public protocol Scalar: Equatable, BitwiseCopyable {
   associatedtype NumericValue
   var convertedEndian: NumericValue { get }
 }

swift/Sources/FlatBuffers/ByteBuffer.swift

@@ -27,7 +27,7 @@ public struct ByteBuffer: @unchecked Sendable {
   @usableFromInline
   final class Storage {
     @usableFromInline
-    enum Blob {
+    @frozen enum Blob: ~Copyable {
       #if !os(WASI)
       case data(Data)
       case bytes(any ContiguousBytes)
@@ -36,6 +36,40 @@ public struct ByteBuffer: @unchecked Sendable {
       case byteBuffer(_InternalByteBuffer)
       case array([UInt8])
       case pointer(UnsafeMutableRawPointer)
+
+      init(_ other: borrowing Blob) {
+        switch other {
+        #if !os(WASI)
+        case .data(let data):
+          self = .data(data)
+        case .bytes(let contiguousBytes):
+          self = .bytes(contiguousBytes)
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          self = .byteBuffer(internalByteBuffer)
+        case .array(let array):
+          self = .array(array)
+        case .pointer(let unsafeMutableRawPointer):
+          self = .pointer(unsafeMutableRawPointer)
+        }
+      }
+
+      var description: String {
+        switch self {
+        #if !os(WASI)
+        case .data(let data):
+          "data: \(data)"
+        case .bytes(let contiguousBytes):
+          "bytes: \(contiguousBytes)"
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          "byteBuffer: \(internalByteBuffer)"
+        case .array(let array):
+          "array: \(array)"
+        case .pointer(let unsafeMutableRawPointer):
+          "pointer: \(unsafeMutableRawPointer)"
+        }
+      }
     }
 
     /// This storage doesn't own the memory, therefore, we won't deallocate on deinit.
@@ -44,7 +78,7 @@ public struct ByteBuffer: @unchecked Sendable {
     private let capacity: Int
     /// Retained blob of data that requires the storage to retain a pointer to.
     @usableFromInline
-    var retainedBlob: Blob
+    let retainedBlob: Blob
 
     @usableFromInline
     init(count: Int) {
@@ -57,9 +91,9 @@ public struct ByteBuffer: @unchecked Sendable {
     }
 
     @usableFromInline
-    init(blob: Blob, capacity count: Int) {
+    init(blob: borrowing Blob, capacity count: Int) {
       capacity = count
-      retainedBlob = blob
+      retainedBlob = .init(blob)
       isOwned = false
     }
 
@@ -150,6 +184,7 @@ public struct ByteBuffer: @unchecked Sendable {
 
     @discardableResult
     @inline(__always)
+    @inlinable
     func readWithUnsafeRawPointer<T>(
       position: Int,
       _ body: (UnsafeRawPointer) throws -> T) rethrows -> T
@@ -278,7 +313,7 @@ public struct ByteBuffer: @unchecked Sendable {
   ///   - removeBytes: Removes a number of bytes from the current size
   @inline(__always)
   init(
-    blob: Storage.Blob,
+    blob: borrowing Storage.Blob,
     count: Int,
     removing removeBytes: Int)
   {
@@ -318,7 +353,8 @@ public struct ByteBuffer: @unchecked Sendable {
   ///   - def: Type of the object
   ///   - position: the index of the object in the buffer
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  @inlinable
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _storage.readWithUnsafeRawPointer(position: position) {
       $0.bindMemory(to: T.self, capacity: 1)
         .pointee
@@ -412,7 +448,7 @@ public struct ByteBuffer: @unchecked Sendable {
   /// - Parameter removeBytes: the amount of bytes to remove from the current Size
   @inline(__always)
   public func duplicate(removing removeBytes: Int = 0) -> ByteBuffer {
-    assert(removeBytes > 0, "Can NOT remove negative bytes")
+    assert(removeBytes >= 0, "Can NOT remove negative bytes")
     assert(
       removeBytes < capacity,
       "Can NOT remove more bytes than the ones allocated")
@@ -464,8 +500,9 @@ public struct ByteBuffer: @unchecked Sendable {
 extension ByteBuffer: CustomDebugStringConvertible {
 
   public var debugDescription: String {
-    """
-    buffer located at: \(_storage.retainedBlob), 
+    let blobDescription = _storage.retainedBlob.description
+    return """
+    buffer located at: \(blobDescription), 
     with capacity of \(capacity),
     { writtenSize: \(_readerIndex), readerSize: \(reader), 
     size: \(size) }

swift/Sources/FlatBuffers/FlatBufferBuilder.swift

@@ -47,7 +47,8 @@ public struct FlatBufferBuilder {
   /// A check to see if finish(::) was ever called to retreive data object
   private(set) var finished = false
   /// A check to see if the buffer should serialize Default values
-  private var serializeDefaults: Bool
+  @usableFromInline
+  let serializeDefaults: Bool
 
   /// Current alignment for the buffer
   var _minAlignment: Int = 0 {
@@ -756,6 +757,7 @@ public struct FlatBufferBuilder {
   ///   - offset: ``Offset`` of another object to be written
   ///   - position: The predefined position of the object
   @inline(__always)
+  @inlinable
   mutating public func add(offset: Offset, at position: VOffset) {
     if offset.isEmpty { return }
     add(element: refer(to: offset.o), def: 0, at: position)
@@ -794,6 +796,7 @@ public struct FlatBufferBuilder {
   ///   - def: Default value for that element
   ///   - position: The predefined position of the element
   @inline(__always)
+  @inlinable
   mutating public func add<T: Scalar>(
     element: T,
     def: T,
@@ -813,6 +816,7 @@ public struct FlatBufferBuilder {
   ///   - element: Optional element of type scalar
   ///   - position: The predefined position of the element
   @inline(__always)
+  @inlinable
   mutating public func add<T: Scalar>(element: T?, at position: VOffset) {
     guard let element = element else { return }
     track(offset: push(element: element), at: position)
@@ -825,6 +829,7 @@ public struct FlatBufferBuilder {
   /// - Parameter element: Element to insert
   /// - returns: position of the Element
   @inline(__always)
+  @inlinable
   @discardableResult
   mutating public func push<T: Scalar>(element: T) -> UOffset {
     let size = MemoryLayout<T>.size
@@ -836,7 +841,8 @@ public struct FlatBufferBuilder {
   }
 
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  @inlinable
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _bb.read(def: def, position: position)
   }
 }

swift/Sources/FlatBuffers/FlatBufferObject.swift

@@ -18,7 +18,7 @@ import Foundation
 
 /// NativeStruct is a protocol that indicates if the struct is a native `swift` struct
 /// since now we will be serializing native structs into the buffer.
-public protocol NativeStruct {}
+public protocol NativeStruct: BitwiseCopyable {}
 
 public protocol FlatBufferVerifiableNativeStruct: NativeStruct, Verifiable {}
 

swift/Sources/FlatBuffers/Table.swift

@@ -82,7 +82,7 @@ public struct Table {
   /// - Parameters:
   ///   - type: Type of Element that needs to be read from the buffer
   ///   - o: Offset of the Element
-  public func readBuffer<T>(of type: T.Type, at o: Int32) -> T {
+  public func readBuffer<T: BitwiseCopyable>(of type: T.Type, at o: Int32) -> T {
     bb.read(def: T.self, position: Int(o &+ position))
   }
 

swift/Sources/FlatBuffers/Verifier.swift

@@ -163,7 +163,7 @@ public struct Verifier {
   /// - Parameter position: Current position to be read
   /// - Throws: `inBuffer` errors
   /// - Returns: a value of type `T` usually a `VTable` or a table offset
-  internal func getValue<T>(at position: Int) throws -> T {
+  internal func getValue<T: BitwiseCopyable>(at position: Int) throws -> T {
     try inBuffer(position: position, of: T.self)
     return _buffer.read(def: T.self, position: position)
   }

swift/Sources/FlatBuffers/_InternalByteBuffer.swift

@@ -30,7 +30,7 @@ struct _InternalByteBuffer {
   @usableFromInline
   final class Storage {
     /// pointer to the start of the buffer object in memory
-    private(set) var memory: UnsafeMutableRawPointer
+    @exclusivity(unchecked) private(set) var memory: UnsafeMutableRawPointer
 
     @usableFromInline
     init(count: Int, alignment: Int) {
@@ -333,6 +333,7 @@ struct _InternalByteBuffer {
 
   @discardableResult
   @inline(__always)
+  @usableFromInline
   func readWithUnsafeRawPointer<T>(
     position: Int,
     _ body: (UnsafeRawPointer) throws -> T) rethrows -> T

swift/Sources/FlexBuffers/ByteBuffer.swift

@@ -27,7 +27,7 @@ public struct ByteBuffer {
   @usableFromInline
   final class Storage {
     @usableFromInline
-    enum Blob {
+    @frozen enum Blob: ~Copyable {
       #if !os(WASI)
       case data(Data)
       case bytes(any ContiguousBytes)
@@ -36,6 +36,23 @@ public struct ByteBuffer {
       case byteBuffer(_InternalByteBuffer)
       case array([UInt8])
       case pointer(UnsafeMutableRawPointer)
+
+      init(_ other: borrowing Blob) {
+        switch other {
+        #if !os(WASI)
+        case .data(let data):
+          self = .data(data)
+        case .bytes(let contiguousBytes):
+          self = .bytes(contiguousBytes)
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          self = .byteBuffer(internalByteBuffer)
+        case .array(let array):
+          self = .array(array)
+        case .pointer(let unsafeMutableRawPointer):
+          self = .pointer(unsafeMutableRawPointer)
+        }
+      }
     }
 
     /// This storage doesn't own the memory, therefore, we won't deallocate on deinit.
@@ -44,7 +61,7 @@ public struct ByteBuffer {
     private let capacity: Int
     /// Retained blob of data that requires the storage to retain a pointer to.
     @usableFromInline
-    var retainedBlob: Blob
+    let retainedBlob: Blob
 
     @usableFromInline
     init(count: Int) {
@@ -57,9 +74,9 @@ public struct ByteBuffer {
     }
 
     @usableFromInline
-    init(blob: Blob, capacity count: Int) {
+    init(blob: borrowing Blob, capacity count: Int) {
       capacity = count
-      retainedBlob = blob
+      retainedBlob = .init(blob)
       isOwned = false
     }
 
@@ -276,7 +293,7 @@ public struct ByteBuffer {
   ///   - removeBytes: Removes a number of bytes from the current size
   @inline(__always)
   init(
-    blob: Storage.Blob,
+    blob: borrowing Storage.Blob,
     count: Int,
     removing removeBytes: Int)
   {
@@ -316,7 +333,7 @@ public struct ByteBuffer {
   ///   - def: Type of the object
   ///   - position: the index of the object in the buffer
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _storage.readWithUnsafeRawPointer(position: position) {
       $0.bindMemory(to: T.self, capacity: 1)
         .pointee
@@ -360,10 +377,10 @@ public struct ByteBuffer {
   @inline(__always)
   func readSizedScalar<
     T: BinaryInteger,
-    T1: BinaryInteger,
-    T2: BinaryInteger,
-    T3: BinaryInteger,
-    T4: BinaryInteger
+    T1: BinaryInteger & BitwiseCopyable,
+    T2: BinaryInteger & BitwiseCopyable,
+    T3: BinaryInteger & BitwiseCopyable,
+    T4: BinaryInteger & BitwiseCopyable
   >(
     def: T.Type,
     t1: T1.Type,

swift/Sources/FlexBuffers/_InternalByteBuffer.swift

@@ -31,7 +31,7 @@ struct _InternalByteBuffer {
   @usableFromInline
   final class Storage {
     /// pointer to the start of the buffer object in memory
-    var memory: UnsafeMutableRawPointer
+    @exclusivity(unchecked) private(set) var memory: UnsafeMutableRawPointer
 
     @usableFromInline
     init(count: Int, alignment: Int) {