Merge pull request #4341 from swiftwasm/main

Author: MaxDesiatov

docs/ReferenceGuides/UnderscoredAttributes.md

@@ -830,3 +830,10 @@ the compiler.
 
 This `async` function uses the pre-SE-0338 semantics of unsafely inheriting the caller's executor.  This is an underscored feature because the right way of inheriting an executor is to pass in the required executor and switch to it.  Unfortunately, there are functions in the standard library which need to inherit their caller's executor but cannot change their ABI because they were not defined as `@_alwaysEmitIntoClient` in the initial release.
 
+## `@_spi_available(platform, version)`
+
+Like `@available`, this attribute indicates a decl is available only as an SPI.
+This implies several behavioral changes comparing to regular `@available`:
+1. Type checker diagnoses when a client accidently exposes such a symbol in library APIs.
+2. When emitting public interfaces, `@_spi_available` is printed as `@available(platform, unavailable)`.
+3. ClangImporter imports ObjC macros `SPI_AVAILABLE` and `__SPI_AVAILABLE` to this attribute.

include/swift/AST/Attr.h

@@ -632,14 +632,16 @@ class AvailableAttr : public DeclAttribute {
                    const llvm::VersionTuple &Obsoleted,
                    SourceRange ObsoletedRange,
                    PlatformAgnosticAvailabilityKind PlatformAgnostic,
-                   bool Implicit)
+                   bool Implicit,
+                   bool IsSPI)
     : DeclAttribute(DAK_Available, AtLoc, Range, Implicit),
       Message(Message), Rename(Rename), RenameDecl(RenameDecl),
       INIT_VER_TUPLE(Introduced), IntroducedRange(IntroducedRange),
       INIT_VER_TUPLE(Deprecated), DeprecatedRange(DeprecatedRange),
       INIT_VER_TUPLE(Obsoleted), ObsoletedRange(ObsoletedRange),
       PlatformAgnostic(PlatformAgnostic),
-      Platform(Platform)
+      Platform(Platform),
+      IsSPI(IsSPI)
   {}
 
 #undef INIT_VER_TUPLE
@@ -685,6 +687,9 @@ class AvailableAttr : public DeclAttribute {
   /// The platform of the availability.
   const PlatformKind Platform;
 
+  /// Whether this is available as SPI.
+  const bool IsSPI;
+
   /// Whether this is a language-version-specific entity.
   bool isLanguageVersionSpecific() const;
 

include/swift/AST/Availability.h

@@ -209,9 +209,12 @@ class UnavailabilityReason {
 /// [lattice]: http://mathworld.wolfram.com/Lattice.html
 class AvailabilityContext {
   VersionRange OSVersion;
+  llvm::Optional<bool> SPI;
 public:
   /// Creates a context that requires certain versions of the target OS.
-  explicit AvailabilityContext(VersionRange OSVersion) : OSVersion(OSVersion) {}
+  explicit AvailabilityContext(VersionRange OSVersion,
+                               llvm::Optional<bool> SPI = llvm::None)
+    : OSVersion(OSVersion), SPI(SPI) {}
 
   /// Creates a context that imposes the constraints of the ASTContext's
   /// deployment target.
@@ -291,6 +294,10 @@ class AvailabilityContext {
   void unionWith(AvailabilityContext other) {
     OSVersion.unionWith(other.getOSVersion());
   }
+
+  bool isAvailableAsSPI() const {
+    return SPI && *SPI;
+  }
 };
 
 

include/swift/AST/Decl.h

@@ -1030,6 +1030,8 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   // an @_spi context.
   bool isSPI() const;
 
+  bool isAvailableAsSPI() const;
+
   // List the SPI groups declared with @_spi or inherited by this decl.
   //
   // SPI groups are inherited from the parent contexts only if the local decl

include/swift/AST/DiagnosticsSema.def

@@ -142,7 +142,7 @@ ERROR(could_not_use_instance_member_on_type,none,
       "%select{| instance of nested}3 type %0",
       (Type, DeclNameRef, Type, bool))
 ERROR(could_not_use_member_on_existential,none,
-      "member %1 cannot be used on value of protocol type %0; consider using a"
+      "member %1 cannot be used on value of type %0; consider using a"
       " generic constraint instead",
       (Type, DeclNameRef))
 FIXIT(replace_with_type,"%0",(Type))
@@ -1542,6 +1542,9 @@ ERROR(optional_attribute_initializer,none,
 ERROR(unavailable_method_non_objc_protocol,none,
       "protocol members can only be marked unavailable in an @objc protocol",
       ())
+ERROR(spi_available_malformed,none,
+      "SPI available only supports introducing version on specific platform",
+      ())
 ERROR(missing_in_class_init_1,none,
       "stored property %0 requires an initial value%select{| or should be "
       "@NSManaged}1", (Identifier, bool))
@@ -1945,9 +1948,8 @@ ERROR(type_cannot_conform_to_nsobject,none,
 ERROR(use_of_equal_instead_of_equality,none,
       "use of '=' in a boolean context, did you mean '=='?", ())
 ERROR(type_cannot_conform, none,
-      "%select{type %1|protocol %1 as a type}0 cannot conform to "
-      "%select{%3|the protocol itself}2",
-      (bool, Type, bool, Type))
+      "type %0 cannot conform to %1",
+      (Type, Type))
 NOTE(only_concrete_types_conform_to_protocols,none,
      "only concrete types such as structs, enums and classes can conform to protocols",
      ())
@@ -2455,8 +2457,8 @@ ERROR(protocol_composition_one_class,none,
       "contains class %1", (Type, Type))
 
 ERROR(requires_conformance_nonprotocol,none,
-      "type %0 constrained to non-protocol, non-class type '%1'",
-      (Type, StringRef))
+      "type %0 constrained to non-protocol, non-class type %1",
+      (Type, Type))
 NOTE(requires_conformance_nonprotocol_fixit,none,
      "use '%0 == %1' to require '%0' to be '%1'",
      (StringRef, StringRef))
@@ -2777,9 +2779,9 @@ WARNING(anyobject_class_inheritance_deprecated,Deprecation,
 ERROR(multiple_inheritance,none,
   "multiple inheritance from classes %0 and %1", (Type, Type))
 ERROR(inheritance_from_non_protocol_or_class,none,
-  "inheritance from non-protocol, non-class type '%0'", (StringRef))
+  "inheritance from non-protocol, non-class type %0", (Type))
 ERROR(inheritance_from_non_protocol,none,
-  "inheritance from non-protocol type '%0'", (StringRef))
+  "inheritance from non-protocol type %0", (Type))
 ERROR(inheritance_from_anyobject,none,
   "only protocols can inherit from 'AnyObject'", ())
 ERROR(inheritance_from_parameterized_protocol,none,
@@ -3589,7 +3591,7 @@ ERROR(construct_protocol_value,none,
       "value of type %0 is a protocol; it cannot be instantiated",
       (Type))
 ERROR(construct_protocol_by_name,none,
-      "protocol type %0 cannot be instantiated",
+      "type %0 cannot be instantiated",
       (Type))
 
 // Operators

include/swift/AST/PrintOptions.h

@@ -548,6 +548,13 @@ struct PrintOptions {
     return result;
   }
 
+  /// The print options used for formatting diagnostic arguments.
+  static PrintOptions forDiagnosticArguments() {
+    PrintOptions result;
+    result.PrintExplicitAny = true;
+    return result;
+  }
+
   /// Retrieve the set of options suitable for diagnostics printing.
   static PrintOptions printForDiagnostics(AccessLevel accessFilter,
                                           bool printFullConvention) {

include/swift/AST/Types.h

@@ -5330,7 +5330,7 @@ class ExistentialType final : public TypeBase {
         ConstraintType(constraintType) {}
 
 public:
-  static Type get(Type constraint);
+  static Type get(Type constraint, bool forceExistential = false);
 
   Type getConstraintType() const { return ConstraintType; }
 
@@ -6663,9 +6663,9 @@ inline bool TypeBase::hasSimpleTypeRepr() const {
     return false;
 
   case TypeKind::Metatype:
-  case TypeKind::ExistentialMetatype:
     return !cast<const AnyMetatypeType>(this)->hasRepresentation();
 
+  case TypeKind::ExistentialMetatype:
   case TypeKind::Existential:
     return false;
 

include/swift/Strings.h

@@ -64,6 +64,10 @@ constexpr static const StringLiteral BUILTIN_TYPE_NAME_PREFIX = "Builtin.";
 constexpr static const StringLiteral CLANG_MODULE_DEFUALT_SPI_GROUP_NAME =
   "OBJC_DEFAULT_SPI_GROUP";
 
+/// The attribute name for @_spi_available
+constexpr static const StringLiteral SPI_AVAILABLE_ATTRNAME =
+  "_spi_available";
+
 /// A composition class containing a StringLiteral for the names of
 /// Swift builtins. The reason we use this is to ensure that we when
 /// necessary slice off the "Builtin." prefix from these names in a

lib/AST/ASTContext.cpp

@@ -4260,15 +4260,17 @@ ProtocolType::ProtocolType(ProtocolDecl *TheDecl, Type Parent,
                            RecursiveTypeProperties properties)
   : NominalType(TypeKind::Protocol, &Ctx, TheDecl, Parent, properties) { }
 
-Type ExistentialType::get(Type constraint) {
+Type ExistentialType::get(Type constraint, bool forceExistential) {
   auto &C = constraint->getASTContext();
-  // FIXME: Any and AnyObject don't yet use ExistentialType.
-  if (constraint->isAny() || constraint->isAnyObject())
-    return constraint;
+  if (!forceExistential) {
+    // FIXME: Any and AnyObject don't yet use ExistentialType.
+    if (constraint->isAny() || constraint->isAnyObject())
+      return constraint;
 
-  // ExistentialMetatypeType is already an existential type.
-  if (constraint->is<ExistentialMetatypeType>())
-    return constraint;
+    // ExistentialMetatypeType is already an existential type.
+    if (constraint->is<ExistentialMetatypeType>())
+      return constraint;
+  }
 
   assert(constraint->isConstraintType());
 

lib/AST/ASTPrinter.cpp

@@ -5171,6 +5171,9 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
     } else if (auto existential = dyn_cast<ExistentialType>(T.getPointer())) {
       if (!Options.PrintExplicitAny)
         return isSimpleUnderPrintOptions(existential->getConstraintType());
+    } else if (auto existential = dyn_cast<ExistentialMetatypeType>(T.getPointer())) {
+      if (!Options.PrintExplicitAny)
+        return isSimpleUnderPrintOptions(existential->getInstanceType());
     }
     return T->hasSimpleTypeRepr();
   }
@@ -5591,10 +5594,32 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       }
     }
 
-    if (T->is<ExistentialMetatypeType>() && Options.PrintExplicitAny)
-      Printer << "any ";
+    Type instanceType = T->getInstanceType();
+    if (Options.PrintExplicitAny) {
+      if (T->is<ExistentialMetatypeType>()) {
+        Printer << "any ";
+
+        // FIXME: We need to replace nested existential metatypes so that
+        // we don't print duplicate 'any'. This will be unnecessary once
+        // ExistentialMetatypeType is split into ExistentialType(MetatypeType).
+        instanceType = Type(instanceType).transform([](Type type) -> Type {
+          if (auto existential = type->getAs<ExistentialMetatypeType>())
+            return MetatypeType::get(existential->getInstanceType());
+
+          return type;
+        });
+      } else if (instanceType->isAny() || instanceType->isAnyObject()) {
+        // FIXME: 'any' is needed to distinguish between '(any Any).Type'
+        // and 'any Any.Type'. However, this combined with the above hack
+        // to replace nested existential metatypes with metatypes causes
+        // a bug in printing nested existential metatypes for Any and AnyObject,
+        // e.g. 'any (any Any).Type.Type'. This will be fixed by using
+        // ExistentialType for Any and AnyObject.
+        instanceType = ExistentialType::get(instanceType, /*forceExistential=*/true);
+      }
+    }
 
-    printWithParensIfNotSimple(T->getInstanceType());
+    printWithParensIfNotSimple(instanceType);
 
     // We spell normal metatypes of existential types as .Protocol.
     if (isa<MetatypeType>(T) &&
@@ -6294,7 +6319,11 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       if (printNamedOpaque())
         return;
 
-      visit(T->getExistentialType());
+      auto constraint = T->getExistentialType();
+      if (auto existential = constraint->getAs<ExistentialType>())
+        constraint = existential->getConstraintType();
+
+      visit(constraint);
       return;
     }
     case PrintOptions::OpaqueReturnTypePrintingMode::StableReference: {

lib/AST/Attr.cpp

@@ -29,6 +29,7 @@
 #include "swift/AST/Types.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/QuotedString.h"
+#include "swift/Strings.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -126,6 +127,7 @@ DeclAttrKind DeclAttribute::getAttrKindFromString(StringRef Str) {
 #define DECL_ATTR(X, CLASS, ...) .Case(#X, DAK_##CLASS)
 #define DECL_ATTR_ALIAS(X, CLASS) .Case(#X, DAK_##CLASS)
 #include "swift/AST/Attr.def"
+  .Case(SPI_AVAILABLE_ATTRNAME, DAK_Available)
   .Default(DAK_Count);
 }
 
@@ -370,6 +372,9 @@ static bool isShortAvailable(const DeclAttribute *DA) {
   if (!AvailAttr)
     return false;
 
+  if (AvailAttr->IsSPI)
+    return false;
+
   if (!AvailAttr->Introduced.hasValue())
     return false;
 
@@ -968,9 +973,23 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
   }
 
   case DAK_Available: {
-    Printer.printAttrName("@available");
-    Printer << "(";
     auto Attr = cast<AvailableAttr>(this);
+    if (!Options.PrintSPIs && Attr->IsSPI) {
+      assert(Attr->hasPlatform());
+      assert(Attr->Introduced.hasValue());
+      Printer.printAttrName("@available");
+      Printer << "(";
+      Printer << Attr->platformString();
+      Printer << ", unavailable)";
+      break;
+    }
+    if (Attr->IsSPI) {
+      std::string atSPI = (llvm::Twine("@") + SPI_AVAILABLE_ATTRNAME).str();
+      Printer.printAttrName(atSPI);
+    } else {
+      Printer.printAttrName("@available");
+    }
+    Printer << "(";
     printAvailableAttr(Attr, Printer, Options);
     Printer << ")";
     break;
@@ -1599,7 +1618,7 @@ AvailableAttr::createPlatformAgnostic(ASTContext &C,
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
     Obsoleted, SourceRange(),
-    Kind, /* isImplicit */ false);
+    Kind, /* isImplicit */ false, /*SPI*/false);
 }
 
 AvailableAttr *AvailableAttr::createForAlternative(
@@ -1610,7 +1629,7 @@ AvailableAttr *AvailableAttr::createForAlternative(
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
-    PlatformAgnosticAvailabilityKind::None, /*Implicit=*/true);
+    PlatformAgnosticAvailabilityKind::None, /*Implicit=*/true, /*SPI*/false);
 }
 
 bool AvailableAttr::isActivePlatform(const ASTContext &ctx) const {
@@ -1628,7 +1647,8 @@ AvailableAttr *AvailableAttr::clone(ASTContext &C, bool implicit) const {
                                Obsoleted ? *Obsoleted : llvm::VersionTuple(),
                                implicit ? SourceRange() : ObsoletedRange,
                                PlatformAgnostic,
-                               implicit);
+                               implicit,
+                               IsSPI);
 }
 
 Optional<OriginallyDefinedInAttr::ActiveVersion>