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SwiftDriver: migrate LLVM bitcode support from tools-support-core
The swift-driver is the only consumer of the bitcode implementation in TSCUtility. Migrate the code to the single user to allow us to deprecate the API in tools-support-core. While there are no practical changes to the implementation, this does take the opportunity to split up the bitcode implementation into multiple files.
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11 files changed

+1437
-10
lines changed

11 files changed

+1437
-10
lines changed

‎Sources/SwiftDriver/CMakeLists.txt‎

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@@ -34,6 +34,15 @@ add_library(SwiftDriver
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Execution/ParsableOutput.swift
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Execution/ProcessProtocol.swift
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"IncrementalCompilation/Bitcode/Bitcode.swift"
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"IncrementalCompilation/Bitcode/BitcodeElement.swift"
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"IncrementalCompilation/Bitcode/Bits.swift"
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"IncrementalCompilation/Bitcode/Bitstream.swift"
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"IncrementalCompilation/Bitcode/BitstreamReader.swift"
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"IncrementalCompilation/Bitcode/BitstreamVisitor.swift"
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"IncrementalCompilation/Bitcode/BitstreamWriter.swift"
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"IncrementalCompilation/Bitcode/BlockInfo.swift"
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"IncrementalCompilation/BuildRecord.swift"
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"IncrementalCompilation/BuildRecordInfo.swift"
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"IncrementalCompilation/DependencyGraphDotFileWriter.swift"

‎Sources/SwiftDriver/IncrementalCompilation/Bitcode/Bitcode.swift‎

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//===--------------- BitCode.swift - LLVM BitCode Helpers ----------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import struct TSCBasic.ByteString
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public struct Bitcode {
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public let signature: Bitcode.Signature
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public let elements: [BitcodeElement]
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public let blockInfo: [UInt64:BlockInfo]
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}
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extension Bitcode {
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public struct Signature: Equatable {
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private var value: UInt32
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public init(value: UInt32) {
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self.value = value
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}
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public init(string: String) {
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precondition(string.utf8.count == 4)
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var result: UInt32 = 0
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for byte in string.utf8.reversed() {
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result <<= 8
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result |= UInt32(byte)
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}
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self.value = result
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}
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}
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}
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extension Bitcode {
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/// Traverse a bitstream using the specified `visitor`, which will receive
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/// callbacks when blocks and records are encountered.
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public static func read<Visitor: BitstreamVisitor>(bytes: ByteString, using visitor: inout Visitor) throws {
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precondition(bytes.count > 4)
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var reader = BitstreamReader(buffer: bytes)
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try visitor.validate(signature: reader.readSignature())
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try reader.readBlock(id: BitstreamReader.fakeTopLevelBlockID,
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abbrevWidth: 2,
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abbrevInfo: [],
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visitor: &visitor)
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}
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}

‎Sources/SwiftDriver/IncrementalCompilation/Bitcode/BitcodeElement.swift‎

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//===--------------- BitcodeElement.swift - LLVM Bitcode Elements --------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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public enum BitcodeElement {
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public struct Block {
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public var id: UInt64
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public var elements: [BitcodeElement]
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}
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/// A record element.
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///
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/// - Warning: A `Record` element's fields and payload only live as long as
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/// the `visit` function that provides them is called. To persist
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/// a record, always make a copy of it.
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public struct Record {
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public enum Payload {
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case none
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case array([UInt64])
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case char6String(String)
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case blob(ArraySlice<UInt8>)
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}
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public var id: UInt64
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public var fields: UnsafeBufferPointer<UInt64>
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public var payload: Payload
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}
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case block(Block)
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case record(Record)
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}
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extension BitcodeElement.Record.Payload: CustomStringConvertible {
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public var description: String {
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switch self {
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case .none:
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return "none"
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case .array(let vals):
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return "array(\(vals))"
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case .char6String(let s):
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return "char6String(\(s))"
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case .blob(let s):
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return "blob(\(s.count) bytes)"
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}
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}
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}

‎Sources/SwiftDriver/IncrementalCompilation/Bitcode/Bits.swift‎

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//===--------------- Bits.swift - Bitstream helpers ----------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import struct TSCBasic.ByteString
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struct Bits: RandomAccessCollection {
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var buffer: ByteString
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var startIndex: Int { return 0 }
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var endIndex: Int { return buffer.count * 8 }
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subscript(index: Int) -> UInt8 {
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let byte = buffer.contents[index / 8]
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return (byte >> UInt8(index % 8)) & 1
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}
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func readBits(atOffset offset: Int, count: Int) -> UInt64 {
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precondition(count >= 0 && count <= 64)
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precondition(offset >= 0)
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precondition(offset &+ count >= offset)
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precondition(offset &+ count <= self.endIndex)
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return buffer.contents.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) in
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let upperBound = offset &+ count
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let topByteIndex = upperBound >> 3
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var result: UInt64 = 0
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if upperBound & 7 != 0 {
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let mask: UInt8 = (1 << UInt8(upperBound & 7)) &- 1
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result = UInt64(bytes[topByteIndex] & mask)
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}
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for i in ((offset >> 3)..<(upperBound >> 3)).reversed() {
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result <<= 8
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result |= UInt64(bytes[i])
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}
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if offset & 7 != 0 {
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result >>= UInt64(offset & 7)
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}
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return result
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}
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}
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}
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extension Bits {
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struct Cursor {
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enum Error: Swift.Error { case bufferOverflow }
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let buffer: Bits
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private var offset: Int = 0
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init(buffer: Bits) {
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self.buffer = buffer
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}
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init(buffer: ByteString) {
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self.init(buffer: Bits(buffer: buffer))
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}
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var isAtStart: Bool {
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return offset == buffer.startIndex
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}
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var isAtEnd: Bool {
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return offset == buffer.count
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}
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func peek(_ count: Int) throws -> UInt64 {
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if buffer.count - offset < count { throw Error.bufferOverflow }
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return buffer.readBits(atOffset: offset, count: count)
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}
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mutating func read(_ count: Int) throws -> UInt64 {
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defer { offset += count }
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return try peek(count)
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}
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mutating func read(bytes count: Int) throws -> ArraySlice<UInt8> {
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precondition(count >= 0)
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precondition(offset & 0b111 == 0)
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let newOffset = offset &+ (count << 3)
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precondition(newOffset >= offset)
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if newOffset > buffer.count { throw Error.bufferOverflow }
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defer { offset = newOffset }
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return buffer.buffer.contents.dropFirst(offset >> 3).prefix((newOffset - offset) >> 3)
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}
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mutating func skip(bytes count: Int) throws {
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precondition(count >= 0)
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precondition(offset & 0b111 == 0)
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let newOffset = offset &+ (count << 3)
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precondition(newOffset >= offset)
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if newOffset > buffer.count { throw Error.bufferOverflow }
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offset = newOffset
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}
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mutating func advance(toBitAlignment align: Int) throws {
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precondition(align > 0)
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precondition(offset &+ (align&-1) >= offset)
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precondition(align & (align &- 1) == 0)
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if offset % align == 0 { return }
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offset = (offset &+ align) & ~(align &- 1)
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if offset > buffer.count { throw Error.bufferOverflow }
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}
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}
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}

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