Merge branch 'main' of github.com:apple/swift into maxd/main-merge

# Conflicts:
#	lib/Driver/WebAssemblyToolChains.cpp

Author: MaxDesiatov

CHANGELOG.md

@@ -19,6 +19,129 @@ _**Note:** This is in reverse chronological order, so newer entries are added to
 Swift 5.6
 ---------
 
+* Actor isolation checking now understands that `defer` bodies share the isolation of their enclosing function.
+
+  ```swift
+  // Works on global actors
+  @MainActor
+  func runAnimation(controller: MyViewController) async {
+    controller.hasActiveAnimation = true
+    defer { controller.hasActiveAnimation = false }
+
+    // do the animation here...
+  }
+
+  // Works on actor instances
+  actor OperationCounter {
+    var activeOperationCount = 0
+
+    func operate() async {
+      activeOperationCount += 1
+      defer { activeOperationCount -= 1 }
+
+      // do work here...
+    }
+  }
+  ```
+
+* [SE-0335][]:
+
+  Swift now allows existential types to be explicitly written with the `any`
+  keyword, creating a syntactic distinction between existential types and
+  protocol conformance constraints. For example:
+
+  ```swift
+  protocol P {}
+
+  func generic<T>(value: T) where T: P {
+    ...
+  }
+
+  func existential(value: any P) {
+     ...
+  }
+  ```
+
+* [SE-0337][]:
+
+  Swift now provides an incremental migration path to data race safety, allowing
+  APIs to adopt concurrency without breaking their clients that themselves have
+  not adopted concurrency. An existing declaration can introduce
+  concurrency-related annotations (such as making its closure parameters
+  `@Sendable`) and use the `@preconcurrency` attribute to maintain its behavior
+  for clients who have not themselves adopted concurrency:
+
+  ```swift
+  // module A
+  @preconcurrency func runOnSeparateTask(_ workItem: @Sendable () -> Void)
+
+  // module B
+  import A
+
+  class MyCounter {
+    var value = 0
+  }
+
+  func doesNotUseConcurrency(counter: MyCounter) {
+    runOnSeparateTask {
+      counter.value += 1 // no warning, because this code hasn't adopted concurrency
+    }
+  }
+
+  func usesConcurrency(counter: MyCounter) async {
+    runOnSeparateTask {
+      counter.value += 1 // warning: capture of non-Sendable type 'MyCounter'
+    }
+  }
+  ```
+
+  One can enable warnings about data race safety within a module with the
+  `-warn-concurrency` compiler option. When using a module that does not yet
+  provide `Sendable` annotations, one can suppress warnings for types from that
+  module by marking the import with `@preconcurrency`:
+
+  ```swift
+  /// module C
+  public struct Point {
+    public var x, y: Double
+  }
+
+  // module D
+  @preconcurrency import C
+
+  func centerView(at location: Point) {
+    Task {
+      await mainView.center(at: location) // no warning about non-Sendable 'Point' because the @preconcurrency import suppresses it
+    }
+  }
+  ```
+
+* [SE-0302][]:
+
+  Swift will now produce warnings to indicate potential data races when
+  non-`Sendable` types are passed across actor or task boundaries. For
+  example:
+
+  ```swift
+  class MyCounter {
+    var value = 0
+  }
+
+  func f() -> MyCounter {
+    let counter = MyCounter()
+    Task {
+      counter.value += 1  // warning: capture of non-Sendable type 'MyCounter'
+    }
+    return counter
+  }
+  ```
+
+* [SE-0331][]:
+
+  The conformance of the unsafe pointer types (e.g., `UnsafePointer`,
+  `UnsafeMutableBufferPointer`) to the `Sendable` protocols has been removed,
+  because pointers cannot safely be transferred across task or actor boundaries.
+
 * References to `Self` or so-called "`Self` requirements" in the type signatures
   of protocol members are now correctly detected in the parent of a nested type.
   As a result, protocol members that fall under this overlooked case are no longer
@@ -39,7 +162,7 @@ Swift 5.6
     // protocol type (use a generic constraint instead).
     _ = p.method
   }
-  ``` 
+  ```
 
 * [SE-0324][]:
 
@@ -66,6 +189,19 @@ Swift 5.6
   }
   ```
 
+* [SE-0322][]:
+
+  The standard library now provides a new operation
+  `withUnsafeTemporaryAllocation` which provides an efficient temporarily
+  allocation within a limited scope, which will be optimized to use stack
+  allocation when possible.
+
+* [SE-0320][]:
+
+  Dictionaries with keys of any type conforming to the new protocol
+  `CodingKeyRepresentable` can now be encoded and decoded. Formerly, encoding
+  and decoding was limited to keys of type `String` or `Int`.
+
 * [SE-0315][]:
 
   Type expressions and annotations can now include "type placeholders" which
@@ -8766,15 +8902,21 @@ Swift 1.0
 [SE-0298]: <https://github.com/apple/swift-evolution/blob/main/proposals/0298-asyncsequence.md>
 [SE-0299]: <https://github.com/apple/swift-evolution/blob/main/proposals/0299-extend-generic-static-member-lookup.md>
 [SE-0300]: <https://github.com/apple/swift-evolution/blob/main/proposals/0300-continuation.md>
+[SE-0302]: <https://github.com/apple/swift-evolution/blob/main/proposals/0302-concurrent-value-and-concurrent-closures.md>
 [SE-0306]: <https://github.com/apple/swift-evolution/blob/main/proposals/0306-actors.md>
 [SE-0310]: <https://github.com/apple/swift-evolution/blob/main/proposals/0310-effectful-readonly-properties.md>
 [SE-0311]: <https://github.com/apple/swift-evolution/blob/main/proposals/0311-task-locals.md>
 [SE-0313]: <https://github.com/apple/swift-evolution/blob/main/proposals/0313-actor-isolation-control.md>
 [SE-0315]: <https://github.com/apple/swift-evolution/blob/main/proposals/0315-placeholder-types.md>
 [SE-0316]: <https://github.com/apple/swift-evolution/blob/main/proposals/0316-global-actors.md>
+[SE-0320]: <https://github.com/apple/swift-evolution/blob/main/proposals/0320-codingkeyrepresentable.md>
+[SE-0322]: <https://github.com/apple/swift-evolution/blob/main/proposals/0322-temporary-buffers.md>
 [SE-0324]: <https://github.com/apple/swift-evolution/blob/main/proposals/0324-c-lang-pointer-arg-conversion.md>
 [SE-0323]: <https://github.com/apple/swift-evolution/blob/main/proposals/0323-async-main-semantics.md>
 [SE-0328]: <https://github.com/apple/swift-evolution/blob/main/proposals/0328-structural-opaque-result-types.md>
+[SE-0331]: <https://github.com/apple/swift-evolution/blob/main/proposals/0331-remove-sendable-from-unsafepointer.md>
+[SE-0337]: <https://github.com/apple/swift-evolution/blob/main/proposals/0337-support-incremental-migration-to-concurrency-checking.md>
+[SE-0335]: <https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md>
 
 [SR-75]: <https://bugs.swift.org/browse/SR-75>
 [SR-106]: <https://bugs.swift.org/browse/SR-106>

SwiftCompilerSources/Sources/Optimizer/InstructionPasses/SimplifyStrongRetainRelease.swift

@@ -76,18 +76,18 @@ private func isNotReferenceCounted(value: Value, context: PassContext) -> Bool {
       return isNotReferenceCounted(value: uci.operand, context: context)
     case let urc as UncheckedRefCastInst:
       return isNotReferenceCounted(value: urc.operand, context: context)
-    case is GlobalValueInst:
+    case let gvi as GlobalValueInst:
       // Since Swift 5.1, statically allocated objects have "immortal" reference
       // counts. Therefore we can safely eliminate unbalaced retains and
       // releases, because they are no-ops on immortal objects.
       // Note that the `simplifyGlobalValuePass` pass is deleting balanced
       // retains/releases, which doesn't require a Swift 5.1 minimum deployment
       // targert.
-      return context.isSwift51RuntimeAvailable
+      return gvi.function.isSwift51RuntimeAvailable
     case let rptr as RawPointerToRefInst:
       // Like `global_value` but for the empty collection singletons from the
       // stdlib, e.g. the empty Array singleton.
-      if context.isSwift51RuntimeAvailable {
+      if rptr.function.isSwift51RuntimeAvailable {
         // The pattern generated for empty collection singletons is:
         //     %0 = global_addr @_swiftEmptyArrayStorage
         //     %1 = address_to_pointer %0

SwiftCompilerSources/Sources/Optimizer/PassManager/PassUtils.swift

@@ -22,10 +22,6 @@ struct PassContext {
 
   let _bridged: BridgedPassContext
 
-  var isSwift51RuntimeAvailable: Bool {
-    PassContext_isSwift51RuntimeAvailable(_bridged) != 0
-  }
-
   var aliasAnalysis: AliasAnalysis {
     let bridgedAA = PassContext_getAliasAnalysis(_bridged)
     return AliasAnalysis(bridged: bridgedAA)

SwiftCompilerSources/Sources/SIL/Function.swift

@@ -52,6 +52,13 @@ final public class Function : CustomStringConvertible, HasName {
   public var argumentTypes: ArgumentTypeArray { ArgumentTypeArray(function: self) }
   public var resultType: Type { SILFunction_getSILResultType(bridged).type }
 
+  /// True, if the function runs with a swift 5.1 runtime.
+  /// Note that this is function specific, because inlinable functions are de-serialized
+  /// in a client module, which might be compiled with a different deployment target.
+  public var isSwift51RuntimeAvailable: Bool {
+    SILFunction_isSwift51RuntimeAvailable(bridged) != 0
+  }
+
   // Only to be called by PassContext
   public func _modifyEffects(_ body: (inout FunctionEffects) -> ()) {
     body(&effects)

docs/ExternalResources.md

@@ -135,6 +135,11 @@ https://medium.com/kinandcartacreated/contributing-to-swift-part-2-efebcf7b6c93
 
 ## Code generation, runtime and ABI
 
+- [Bringing Swift to Windows][] by Saleem Abdulrasool (talk, Nov 2019): This talk
+  covers the story of bringing Swift to Windows from the ground up through an unusual
+  route: cross-compilation on Linux. It covers interesting challenges in porting
+  the Swift compiler, standard library, and core libraries that were overcome in the
+  process of bringing Swift to a platform that challenges the Unix design assumptions.
 - [The Swift Runtime][] by Jordan Rose (blog post series, Aug-Oct 2020):
   This blog post series describes the runtime layout for different structures,
   runtime handling for metadata, as well as basic runtime functionality such
@@ -187,6 +192,7 @@ https://medium.com/kinandcartacreated/contributing-to-swift-part-2-efebcf7b6c93
   value witness tables, type metadata, abstraction patterns, reabstraction,
   reabstraction thunks and protocol witness tables.
 
+[Bringing Swift to Windows]: https://www.youtube.com/watch?v=Zjlxa1NIfJc
 [Mac OS 9]: https://belkadan.com/blog/2020/04/Swift-on-Mac-OS-9/
 [The Swift Runtime]: https://belkadan.com/blog/tags/swift-runtime/
 [Part 1: Heap Objects]: https://belkadan.com/blog/2020/08/Swift-Runtime-Heap-Objects/

include/swift/ABI/ObjectFile.h

@@ -28,6 +28,9 @@ class SwiftObjectFileFormat {
 public:
   virtual ~SwiftObjectFileFormat() {}
   virtual llvm::StringRef getSectionName(ReflectionSectionKind section) = 0;
+  virtual llvm::Optional<llvm::StringRef> getSegmentName() {
+    return {};
+  }
 };
 
 /// Responsible for providing the Mach-O reflection section identifiers.
@@ -50,6 +53,9 @@ class SwiftObjectFileFormatMachO : public SwiftObjectFileFormat {
     }
     llvm_unreachable("Section type not found.");
   }
+  llvm::Optional<llvm::StringRef> getSegmentName() override {
+    return {"__TEXT"};
+  }
 };
 
 /// Responsible for providing the ELF reflection section identifiers.

include/swift/AST/ASTContext.h

@@ -659,6 +659,50 @@ class ASTContext final {
   // Retrieve the declaration of Swift._stdlib_isOSVersionAtLeast.
   FuncDecl *getIsOSVersionAtLeastDecl() const;
 
+  /// Retrieve the declaration of DistributedActorSystem.remoteCall(Void)(...).
+  ///
+  /// \param actorOrSystem distributed actor or actor system to get the
+  /// remoteCall function for. Since the method we're looking for is an ad-hoc
+  /// requirement, a specific type MUST be passed here as it is not possible
+  /// to obtain the decl from just the `DistributedActorSystem` protocol type.
+  /// \param isVoidReturn true if the call will be returning `Void`.
+  AbstractFunctionDecl *getRemoteCallOnDistributedActorSystem(
+      NominalTypeDecl *actorOrSystem,
+      bool isVoidReturn) const;
+
+  /// Retrieve the declaration of DistributedActorSystem.make().
+  ///
+  /// \param actorOrSystem distributed actor or actor system to get the
+  /// remoteCall function for. Since the method we're looking for is an ad-hoc
+  /// requirement, a specific type MUST be passed here as it is not possible
+  /// to obtain the decl from just the `DistributedActorSystem` protocol type.
+  FuncDecl *getMakeInvocationEncoderOnDistributedActorSystem(
+      NominalTypeDecl *actorOrSystem) const;
+
+  // Retrieve the declaration of DistributedInvocationEncoder.recordArgument(_:).
+  //
+  // \param nominal optionally provide a 'NominalTypeDecl' from which the
+  // function decl shall be extracted. This is useful to avoid witness calls
+  // through the protocol which is looked up when nominal is null.
+  FuncDecl *getRecordArgumentOnDistributedInvocationEncoder(
+      NominalTypeDecl *nominal) const;
+
+  // Retrieve the declaration of DistributedInvocationEncoder.recordErrorType(_:).
+  FuncDecl *getRecordErrorTypeOnDistributedInvocationEncoder(
+      NominalTypeDecl *nominal) const;
+
+  // Retrieve the declaration of DistributedInvocationEncoder.recordReturnType(_:).
+  FuncDecl *getRecordReturnTypeOnDistributedInvocationEncoder(
+      NominalTypeDecl *nominal) const;
+
+  // Retrieve the declaration of DistributedInvocationEncoder.doneRecording().
+  //
+  // \param nominal optionally provide a 'NominalTypeDecl' from which the
+  // function decl shall be extracted. This is useful to avoid witness calls
+  // through the protocol which is looked up when nominal is null.
+  FuncDecl *getDoneRecordingOnDistributedInvocationEncoder(
+      NominalTypeDecl *nominal) const;
+
   /// Look for the declaration with the given name within the
   /// passed in module.
   void lookupInModule(ModuleDecl *M, StringRef name,

include/swift/AST/ASTMangler.h

@@ -70,7 +70,7 @@ class ASTMangler : public Mangler {
   /// Whether the mangling predates concurrency, and therefore shouldn't
   /// include concurrency features such as global actors or @Sendable
   /// function types.
-  bool PredatesConcurrency = false;
+  bool Preconcurrency = false;
 
 public:
   using SymbolicReferent = llvm::PointerUnion<const NominalTypeDecl *,

include/swift/AST/Attr.def

@@ -691,9 +691,9 @@ SIMPLE_DECL_ATTR(_noAllocation, NoAllocation,
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   124)
 
-SIMPLE_DECL_ATTR(_predatesConcurrency, PredatesConcurrency,
+SIMPLE_DECL_ATTR(preconcurrency, Preconcurrency,
   OnFunc | OnConstructor | OnProtocol | OnGenericType | OnVar | OnSubscript |
-  OnEnumElement | OnImport | UserInaccessible |
+  OnEnumElement | OnImport |
   ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
   125)