Merge main 2021-02-18

CHANGELOG.md

@@ -28,6 +28,20 @@ CHANGELOG
 Swift Next
 ----------
 
+* Whenever a reference to `Self` does not impede the usage of a protocol as a value type, or a protocol member on a value of protocol type, the same is now true for references to `[Self]` and `[Key : Self]`:
+
+  ```swift
+  protocol Copyable {
+    func copy() -> Self
+    func copy(count: Int) -> [Self]
+  }
+
+  func test(c: Copyable) {
+    let copy: Copyable = c.copy() // OK
+    let copies: [Copyable] = c.copy(count: 5) // also OK
+  }
+  ```
+
 * [SE-0296][]:
 
   Asynchronous programming is now natively supported using async/await. Asynchronous functions can be defined using `async`:

CMakeLists.txt

@@ -196,6 +196,13 @@ if(SWIFT_PROFDATA_FILE AND EXISTS ${SWIFT_PROFDATA_FILE})
   add_definitions("-fprofile-instr-use=${SWIFT_PROFDATA_FILE}")
 endif()
 
+option(USE_SWIFT_ASYNC_LOWERING
+       "Indicates if Swiftc should use async-specific lowering for async
+        functions if it is supported for the target. The runtime also checks
+        this setting before using async-specific attributes. This only applies
+        to the async calling convention and not to the async context attribute."
+	FALSE)
+
 #
 # User-configurable Swift Standard Library specific options.
 #

docs/ABI/Mangling.rst

@@ -167,6 +167,8 @@ Globals
   global ::= protocol-conformance protocol 'Wb' // base protocol witness table accessor
   global ::= type protocol-conformance 'Wl' // lazy protocol witness table accessor
 
+  global ::= global generic-signature? 'WJ' DIFFERENTIABILITY-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // differentiability witness
+
   global ::= type 'WV'                   // value witness table
   global ::= entity 'Wvd'                // field offset
   global ::= entity 'WC'                 // resilient enum tag index
@@ -222,13 +224,17 @@ types where the metadata itself has unknown layout.)
   global ::= from-type to-type generic-signature? 'TR'  // reabstraction thunk
   global ::= impl-function-type type 'Tz'     // objc-to-swift-async completion handler block implementation
   global ::= impl-function-type type 'TZ'     // objc-to-swift-async completion handler block implementation (predefined by runtime)
+  global ::= from-type to-type generic-signature? 'TR'  // reabstraction thunk
+  global ::= impl-function-type type generic-signature? 'Tz'     // objc-to-swift-async completion handler block implementation
+  global ::= impl-function-type type generic-signature? 'TZ'     // objc-to-swift-async completion handler block implementation (predefined by runtime)
   global ::= from-type to-type self-type generic-signature? 'Ty'  // reabstraction thunk with dynamic 'Self' capture
   global ::= from-type to-type generic-signature? 'Tr'  // obsolete mangling for reabstraction thunk
   global ::= entity generic-signature? type type* 'TK' // key path getter
   global ::= entity generic-signature? type type* 'Tk' // key path setter
   global ::= type generic-signature 'TH' // key path equality
   global ::= type generic-signature 'Th' // key path hasher
   global ::= global generic-signature? 'TJ' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff function
+  global ::= global generic-signature? 'TJV' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff derivative vtable thunk
   global ::= from-type to-type 'TJO' AUTODIFF-FUNCTION-KIND // autodiff self-reordering reabstraction thunk
   global ::= from-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff linear map subset parameters thunk
   global ::= global to-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff derivative function subset parameters thunk

docs/SIL.rst

@@ -1590,12 +1590,15 @@ Differentiability Witnesses
   sil-differentiability-witness ::=
       'sil_differentiability_witness'
       sil-linkage?
+      '[' differentiability-kind ']'
       '[' 'parameters' sil-differentiability-witness-function-index-list ']'
       '[' 'results' sil-differentiability-witness-function-index-list ']'
       generic-parameter-clause?
       sil-function-name ':' sil-type
       sil-differentiability-witness-body?
 
+  differentiability-kind ::= 'forward' | 'reverse' | 'normal' | 'linear'
+
   sil-differentiability-witness-body ::=
       '{' sil-differentiability-witness-entry?
           sil-differentiability-witness-entry? '}'
@@ -1625,7 +1628,7 @@ based on the key.
 
 ::
 
-  sil_differentiability_witness hidden [parameters 0] [results 0] <T where T : Differentiable> @id : $@convention(thin) (T) -> T {
+  sil_differentiability_witness hidden [normal] [parameters 0] [results 0] <T where T : Differentiable> @id : $@convention(thin) (T) -> T {
     jvp: @id_jvp : $@convention(thin) (T) -> (T, @owned @callee_guaranteed (T.TangentVector) -> T.TangentVector)
     vjp: @id_vjp : $@convention(thin) (T) -> (T, @owned @callee_guaranteed (T.TangentVector) -> T.TangentVector)
   }
@@ -7066,6 +7069,7 @@ differentiability_witness_function
   sil-instruction ::=
       'differentiability_witness_function'
       '[' sil-differentiability-witness-function-kind ']'
+      '[' differentiability-kind ']'
       '[' 'parameters' sil-differentiability-witness-function-index-list ']'
       '[' 'results' sil-differentiability-witness-function-index-list ']'
       generic-parameter-clause?
@@ -7074,7 +7078,7 @@ differentiability_witness_function
   sil-differentiability-witness-function-kind ::= 'jvp' | 'vjp' | 'transpose'
   sil-differentiability-witness-function-index-list ::= [0-9]+ (' ' [0-9]+)*
 
-  differentiability_witness_function [jvp] [parameters 0] [results 0] \
+  differentiability_witness_function [vjp] [reverse] [parameters 0] [results 0] \
     <T where T: Differentiable> @foo : $(T) -> T
 
 Looks up a differentiability witness function (JVP, VJP, or transpose) for
@@ -7086,6 +7090,7 @@ look up: ``[jvp]``, ``[vjp]``, or ``[transpose]``.
 The remaining components identify the SIL differentiability witness:
 
 - Original function name.
+- Differentiability kind.
 - Parameter indices.
 - Result indices.
 - Witness generic parameter clause (optional). When parsing SIL, the parsed

include/swift/ABI/Task.h

@@ -300,15 +300,15 @@ class AsyncTask : public HeapObject, public Job {
                 // therefore skip also skip pointing to that parent and point
                 // to whichever parent it was pointing to as well, it may be its
                 // immediate parent, or some super-parent.
-                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext());
+                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext()) |
                                   static_cast<uintptr_t>(NextLinkType::IsParent);
                 break;
               case NextLinkType::IsNext:
                 assert(false && "empty taskValue head in parent task, yet parent's 'head' is `IsNext`, "
                                 "this should not happen, as it implies the parent must have stored some value.");
                 break;
               case NextLinkType::IsTerminal:
-                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext());
+                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext()) | 
                                   static_cast<uintptr_t>(NextLinkType::IsTerminal);
                 break;
             }
@@ -845,8 +845,10 @@ class AsyncTask : public HeapObject, public Job {
     /// The type of the result that will be produced by the future.
     const Metadata *resultType;
 
-    // Trailing storage for the result itself. The storage will be uninitialized,
-    // contain an instance of \c resultType, or contain an an \c Error.
+    SwiftError *error = nullptr;
+
+    // Trailing storage for the result itself. The storage will be
+    // uninitialized, contain an instance of \c resultType.
 
     friend class AsyncTask;
 
@@ -865,25 +867,20 @@ class AsyncTask : public HeapObject, public Job {
     }
 
     /// Retrieve the error.
-    SwiftError *&getError() {
-      return *reinterpret_cast<SwiftError **>(
-           reinterpret_cast<char *>(this) + storageOffset(resultType));
-    }
+    SwiftError *&getError() { return *&error; }
 
     /// Compute the offset of the storage from the base of the future
     /// fragment.
     static size_t storageOffset(const Metadata *resultType)  {
       size_t offset = sizeof(FutureFragment);
-      size_t alignment =
-          std::max(resultType->vw_alignment(), alignof(SwiftError *));
+      size_t alignment = resultType->vw_alignment();
       return (offset + alignment - 1) & ~(alignment - 1);
     }
 
     /// Determine the size of the future fragment given a particular future
     /// result type.
     static size_t fragmentSize(const Metadata *resultType) {
-      return storageOffset(resultType) +
-          std::max(resultType->vw_size(), sizeof(SwiftError *));
+      return storageOffset(resultType) + resultType->vw_size();
     }
   };
 
@@ -1038,7 +1035,7 @@ class YieldingAsyncContext : public AsyncContext {
 /// futures.
 class FutureAsyncContext : public AsyncContext {
 public:
-  SwiftError *errorResult = nullptr;
+  SwiftError **errorResult = nullptr;
   OpaqueValue *indirectResult;
 
   using AsyncContext::AsyncContext;

include/swift/AST/ASTMangler.h

@@ -171,17 +171,20 @@ class ASTMangler : public Mangler {
   /// predefined in the Swift runtime for the given type signature.
   std::string mangleObjCAsyncCompletionHandlerImpl(CanSILFunctionType BlockType,
                                                    CanType ResultType,
+                                                   CanGenericSignature Sig,
                                                    bool predefined);
 
-  /// Mangle the derivative function (JVP/VJP) for the given:
+  /// Mangle the derivative function (JVP/VJP), or optionally its vtable entry
+  /// thunk, for the given:
   /// - Mangled original function declaration.
   /// - Derivative function kind.
   /// - Derivative function configuration: parameter/result indices and
   ///   derivative generic signature.
   std::string
   mangleAutoDiffDerivativeFunction(const AbstractFunctionDecl *originalAFD,
                                    AutoDiffDerivativeFunctionKind kind,
-                                   AutoDiffConfig config);
+                                   AutoDiffConfig config,
+                                   bool isVTableThunk = false);
 
   /// Mangle the linear map (differential/pullback) for the given:
   /// - Mangled original function declaration.
@@ -201,6 +204,11 @@ class ASTMangler : public Mangler {
       CanType fromType, CanType toType, GenericSignature signature,
       AutoDiffLinearMapKind linearMapKind);
 
+  /// Mangle a SIL differentiability witness.
+  std::string mangleSILDifferentiabilityWitness(StringRef originalName,
+                                                DifferentiabilityKind kind,
+                                                AutoDiffConfig config);
+
   /// Mangle the AutoDiff generated declaration for the given:
   /// - Generated declaration kind: linear map struct or branching trace enum.
   /// - Mangled original function name.
@@ -214,14 +222,6 @@ class ASTMangler : public Mangler {
                                      AutoDiffLinearMapKind linearMapKind,
                                      AutoDiffConfig config);
 
-  /// Mangle a SIL differentiability witness key:
-  /// - Mangled original function name.
-  /// - Parameter indices.
-  /// - Result indices.
-  /// - Derivative generic signature (optional).
-  std::string
-  mangleSILDifferentiabilityWitnessKey(SILDifferentiabilityWitnessKey key);
-
   std::string mangleKeyPathGetterThunkHelper(const AbstractStorageDecl *property,
                                              GenericSignature signature,
                                              CanType baseType,
@@ -447,7 +447,8 @@ class ASTMangler : public Mangler {
 
   void beginManglingWithAutoDiffOriginalFunction(
       const AbstractFunctionDecl *afd);
-  void appendAutoDiffFunctionParts(char functionKindCode,
+  void appendAutoDiffFunctionParts(StringRef op, 
+                                   Demangle::AutoDiffFunctionKind kind,
                                    AutoDiffConfig config);
   void appendIndexSubset(IndexSubset *indexSubset);
 };

include/swift/AST/ASTTypeIDZone.def

@@ -31,8 +31,8 @@ SWIFT_TYPEID(PropertyWrapperTypeInfo)
 SWIFT_TYPEID(Requirement)
 SWIFT_TYPEID(ResilienceExpansion)
 SWIFT_TYPEID(FragileFunctionKind)
-SWIFT_TYPEID(FunctionRethrowingKind)
-SWIFT_TYPEID(ProtocolRethrowsRequirementList)
+SWIFT_TYPEID(PolymorphicEffectKind)
+SWIFT_TYPEID(PolymorphicEffectRequirementList)
 SWIFT_TYPEID(TangentPropertyInfo)
 SWIFT_TYPEID(SymbolSourceMap)
 SWIFT_TYPEID(Type)

include/swift/AST/ASTTypeIDs.h

@@ -64,8 +64,8 @@ class ProtocolDecl;
 class Requirement;
 enum class ResilienceExpansion : unsigned;
 struct FragileFunctionKind;
-enum class FunctionRethrowingKind : uint8_t;
-class ProtocolRethrowsRequirementList;
+enum class PolymorphicEffectKind : uint8_t;
+class PolymorphicEffectRequirementList;
 class SourceFile;
 class SymbolSourceMap;
 struct TangentPropertyInfo;

include/swift/AST/Attr.def

@@ -353,25 +353,25 @@ SIMPLE_DECL_ATTR(testable, Testable,
 DECL_ATTR(_alignment, Alignment,
   OnStruct | OnEnum |
   UserInaccessible |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
   56)
 SIMPLE_DECL_ATTR(rethrows, Rethrows,
-  OnFunc | OnAccessor | OnConstructor |
+  OnFunc | OnConstructor |
   RejectByParser |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
   57)
 SIMPLE_DECL_ATTR(rethrows, AtRethrows,
   OnProtocol |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
   58)
 DECL_ATTR(_swift_native_objc_runtime_base, SwiftNativeObjCRuntimeBase,
   OnClass |
   UserInaccessible |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
   59)
 CONTEXTUAL_SIMPLE_DECL_ATTR(indirect, Indirect, DeclModifier |
   OnEnum | OnEnumElement |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
   60)
 SIMPLE_DECL_ATTR(warn_unqualified_access, WarnUnqualifiedAccess,
   OnFunc | OnAccessor /*| OnVar*/ |
@@ -469,7 +469,7 @@ DECL_ATTR(_dynamicReplacement, DynamicReplacement,
 SIMPLE_DECL_ATTR(_borrowed, Borrowed,
   OnVar | OnSubscript | UserInaccessible |
   NotSerialized |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIBreakingToRemove | APIStableToAdd | APIStableToRemove,
   81)
 DECL_ATTR(_private, PrivateImport,
   OnImport |
@@ -479,7 +479,7 @@ DECL_ATTR(_private, PrivateImport,
   82)
 SIMPLE_DECL_ATTR(_alwaysEmitIntoClient, AlwaysEmitIntoClient,
   OnVar | OnSubscript | OnAbstractFunction | UserInaccessible |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIBreakingToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   83)
 
 SIMPLE_DECL_ATTR(_implementationOnly, ImplementationOnly,
@@ -613,6 +613,17 @@ SIMPLE_DECL_ATTR(_marker, Marker,
   APIBreakingToAdd | APIBreakingToRemove,
   108)
 
+SIMPLE_DECL_ATTR(reasync, Reasync,
+  OnFunc | OnConstructor |
+  RejectByParser |
+  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
+  109)
+
+SIMPLE_DECL_ATTR(reasync, AtReasync,
+  OnProtocol |
+  ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
+  110)
+
 #undef TYPE_ATTR
 #undef DECL_ATTR_ALIAS
 #undef CONTEXTUAL_DECL_ATTR_ALIAS