Merge branch 'master' of github.com:apple/swift into tensorflow-stage

* 'master' of github.com:apple/swift:
  Make MinSizeRel builds of stdlib (but not the compiler) produce debug info (swiftlang#33787)
  Add result checking to the ChaCha benchmark.
  [ConstraintSystem] Adjust overload filtering to be less aggressive in code completion mode
  Store Clang module imports in addition to Swift overlay.
  LLVM-Passes: add pointer authentication to Swift's function merge pass.
  Update doc and links to support new main branch
  [benchmark] Tweak naming and workload for two new tests
  [benchmark] Add another floating point conversion benchmark
  [benchmark] Add another test to floating point conversion benchmark

Author: pschuh

README.md

@@ -5,7 +5,7 @@
 | **macOS** | Google Kokoro | ![Build Status](https://storage.googleapis.com/tensorflow-kokoro-build-badges/macos-swift-tf-release.svg) | - |
 | **Ubuntu 16.04** | Swift.org CI | [![Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-16.04-tensorflow/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-16.04-tensorflow) | [![Build Status](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-16.04-tensorflow-gpu/lastCompletedBuild/badge/icon)](https://ci-external.swift.org/job/oss-swift-RA-linux-ubuntu-16.04-tensorflow-gpu) |
 
-| | **Architecture** | **Master** | **Package** |
+| | **Architecture** | **main** | **Package** |
 |---|:---:|:---:|:---:|
 | **macOS**        | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-osx/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-osx)|[![Build Status](https://ci.swift.org/job/oss-swift-package-osx/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-osx)|
 | **Ubuntu 16.04** | x86_64 | [![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-16_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-16_04)|[![Build Status](https://ci.swift.org/job/oss-swift-package-linux-ubuntu-16_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-linux-ubuntu-16_04)|

benchmark/README.md

@@ -8,11 +8,11 @@ To run Swift benchmarks, pass the `--benchmark` flag to `build-script`. The
 current benchmark results will be compared to the previous run's results if
 available. Results for each benchmark run are logged for future comparison.
 
-For branch based development, take a baseline benchmark on the Swift `master`
+For branch based development, take a baseline benchmark on the Swift `main`
 branch, switch to a development branch containing potentially performance
 impacting changes, and run the benchmarks again. Upon benchmark completion, the
 benchmark results for the development branch will be compared to the most
-recent benchmark results for `master`.
+recent benchmark results for `main`.
 
 ## Building the Swift Benchmarks
 
@@ -181,7 +181,7 @@ benchmarks will be compiled with -Onone!**
 * `--list`
     * Print a list of available tests matching specified criteria
 * `--tags`
-    * Run tests that are labeled with specified [tags](https://github.com/apple/swift/blob/master/benchmark/utils/TestsUtils.swift#L19)
+    * Run tests that are labeled with specified [tags](https://github.com/apple/swift/blob/main/benchmark/utils/TestsUtils.swift#L19)
      (comma separated list); multiple tags are interpreted as logical AND, i.e.
      run only test that are labeled with all the supplied tags
 * `--skip-tags`

benchmark/scripts/Benchmark_Driver

@@ -975,9 +975,9 @@ def parse_args(args):
     )
     compare_parser.add_argument(
         "--baseline-branch",
-        default="master",
+        default="main",
         help="attempt to compare results to baseline results for specified "
-        "branch (default: master)",
+        "branch (default: main)",
     )
     compare_parser.set_defaults(func=compare)
 

benchmark/single-source/ChaCha.swift

@@ -22,6 +22,7 @@ import TestsUtils
 enum ChaCha20 { }
 
 extension ChaCha20 {
+    @inline(never)
     public static func encrypt<Key: Collection, Nonce: Collection, Bytes: MutableCollection>(bytes: inout Bytes, key: Key, nonce: Nonce, initialCounter: UInt32 = 0) where Bytes.Element == UInt8, Key.Element == UInt8, Nonce.Element == UInt8 {
         var baseState = ChaChaState(key: key, nonce: nonce, counter: initialCounter)
         var index = bytes.startIndex
@@ -347,13 +348,28 @@ public let ChaCha = BenchmarkInfo(
   runFunction: run_ChaCha,
   tags: [.runtime, .cpubench])
 
+@inline(never)
+func checkResult(_ plaintext: [UInt8]) {
+    CheckResults(plaintext.first! == 6 && plaintext.last! == 254)
+    var hash: UInt64 = 0
+    for byte in plaintext {
+        // rotate
+        hash = (hash &<< 8) | (hash &>> (64 - 8))
+        hash ^= UInt64(byte)
+    }
+    CheckResults(hash == 0xa1bcdb217d8d14e4)
+}
 
 @inline(never)
 public func run_ChaCha(_ N: Int) {
-  var plaintext = Array(repeating: UInt8(0), count: 30720)  // Chosen for CI runtime
   let key = Array(repeating: UInt8(1), count: 32)
   let nonce = Array(repeating: UInt8(2), count: 12)
 
+  var checkedtext = Array(repeating: UInt8(0), count: 1024)
+  ChaCha20.encrypt(bytes: &checkedtext, key: key, nonce: nonce)
+  checkResult(checkedtext)
+
+  var plaintext = Array(repeating: UInt8(0), count: 30720)  // Chosen for CI runtime
   for _ in 1...N {
     ChaCha20.encrypt(bytes: &plaintext, key: key, nonce: nonce)
     blackHole(plaintext.first!)

benchmark/single-source/FloatingPointConversion.swift

@@ -18,6 +18,16 @@ public let FloatingPointConversion = [
     runFunction: run_ConvertFloatingPoint_MockFloat64ToDouble,
     tags: [.validation, .api],
     setUpFunction: { blackHole(mockFloat64s) }),
+  BenchmarkInfo(
+    name: "ConvertFloatingPoint.MockFloat64Exactly",
+    runFunction: run_ConvertFloatingPoint_MockFloat64Exactly,
+    tags: [.validation, .api],
+    setUpFunction: { blackHole(mockFloat64s) }),
+  BenchmarkInfo(
+    name: "ConvertFloatingPoint.MockFloat64Exactly2",
+    runFunction: run_ConvertFloatingPoint_MockFloat64Exactly2,
+    tags: [.validation, .api],
+    setUpFunction: { blackHole(mockFloat64s) }),
   BenchmarkInfo(
     name: "ConvertFloatingPoint.MockFloat64ToInt64",
     runFunction: run_ConvertFloatingPoint_MockFloat64ToInt64,
@@ -130,6 +140,11 @@ struct MockFloat64: MockBinaryFloatingPoint {
   init(_ _value: Double) { self._value = _value }
 }
 
+struct MockFloat32: MockBinaryFloatingPoint {
+  var _value: Float
+  init(_ _value: Float) { self._value = _value }
+}
+
 let doubles = [
    1.8547832857295,  26.321549267719135, 98.9544480962058,    73.70286973782363,
   82.04918555938816, 76.38902969312758,  46.35647857011161,   64.0821426030317,
@@ -147,20 +162,40 @@ let doubles = [
 
 let mockFloat64s = doubles.map { MockFloat64($0) }
 
+// See also: test/SILOptimizer/floating_point_conversion.swift
+
+@inline(never)
+public func run_ConvertFloatingPoint_MockFloat64ToDouble(_ N: Int) {
+  for _ in 0..<(N * 100) {
+    for element in mockFloat64s {
+      let f = Double(identity(element))
+      blackHole(f)
+    }
+  }
+}
+
 @inline(__always)
 func convert<
   T: BinaryFloatingPoint, U: BinaryFloatingPoint
->(_ value: T, to: U.Type) -> U {
-  U(value)
+>(exactly value: T, to: U.Type) -> U? {
+  U(exactly: value)
 }
 
-// See also: test/SILOptimizer/floating_point_conversion.swift
+@inline(never)
+public func run_ConvertFloatingPoint_MockFloat64Exactly(_ N: Int) {
+  for _ in 0..<(N * 25) {
+    for element in mockFloat64s {
+      let f = convert(exactly: identity(element), to: Double.self)
+      blackHole(f)
+    }
+  }
+}
 
 @inline(never)
-public func run_ConvertFloatingPoint_MockFloat64ToDouble(_ N: Int) {
-  for _ in 0..<(N * 100) {
+public func run_ConvertFloatingPoint_MockFloat64Exactly2(_ N: Int) {
+  for _ in 0..<(N * 25) {
     for element in mockFloat64s {
-      let f = Double(identity(element))
+      let f = convert(exactly: identity(element), to: MockFloat32.self)
       blackHole(f)
     }
   }

docs/ABI/RegisterUsage.md

@@ -1,6 +1,6 @@
 ## 64-Bit Architecture Register Usage
 
-From Swift 5, the calling convention register allocation for 64-bit architectures is largely based on [existing](https://developer.apple.com/library/content/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html) [standards](https://developer.apple.com/library/content/documentation/DeveloperTools/Conceptual/LowLevelABI/140-x86-64_Function_Calling_Conventions/x86_64.html), with the addition of the context and error return registers discussed in the [ABI stability manifesto](https://github.com/apple/swift/blob/master/docs/ABIStabilityManifesto.md):
+From Swift 5, the calling convention register allocation for 64-bit architectures is largely based on [existing](https://developer.apple.com/library/content/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html) [standards](https://developer.apple.com/library/content/documentation/DeveloperTools/Conceptual/LowLevelABI/140-x86-64_Function_Calling_Conventions/x86_64.html), with the addition of the context and error return registers discussed in the [ABI stability manifesto](https://github.com/apple/swift/blob/main/docs/ABIStabilityManifesto.md):
 
 | Register Purpose | ARM64 | x86_64 |
 | ------------- |:-------------:| ----- |