Merge pull request #26684 from slavapestov/is-iuo-request

Introduce IsImplicitlyUnwrappedOptionalRequest

Author: slavapestov

include/swift/AST/Attr.def

@@ -348,10 +348,7 @@ DECL_ATTR(_restatedObjCConformance, RestatedObjCConformance,
   LongAttribute | RejectByParser |
   NotSerialized, 70)
 // NOTE: 71 is unused
-SIMPLE_DECL_ATTR(_implicitly_unwrapped_optional, ImplicitlyUnwrappedOptional,
-  OnFunc | OnAccessor | OnVar | OnParam | OnSubscript | OnConstructor |
-  RejectByParser,
-  72)
+// NOTE: 72 is unused
 DECL_ATTR(_optimize, Optimize,
   OnAbstractFunction | OnSubscript | OnVar |
   UserInaccessible,

include/swift/AST/Decl.h

@@ -456,16 +456,16 @@ class alignas(1 << DeclAlignInBits) Decl {
     IsTransparentComputed : 1
   );
 
-  SWIFT_INLINE_BITFIELD(ConstructorDecl, AbstractFunctionDecl, 3+2+1,
+  SWIFT_INLINE_BITFIELD(ConstructorDecl, AbstractFunctionDecl, 3+1+1,
     /// The body initialization kind (+1), or zero if not yet computed.
     ///
     /// This value is cached but is not serialized, because it is a property
     /// of the definition of the constructor that is useful only to semantic
     /// analysis and SIL generation.
     ComputedBodyInitKind : 3,
 
-    /// The failability of this initializer, which is an OptionalTypeKind.
-    Failability : 2,
+    /// Whether this constructor can fail, by building an Optional type.
+    Failable : 1,
 
     /// Whether this initializer is a stub placed into a subclass to
     /// catch invalid delegations to a designated initializer not
@@ -2412,12 +2412,20 @@ class ValueDecl : public Decl {
     /// Whether this declaration is 'final'. A final class can't be subclassed,
     /// a final class member can't be overriden.
     unsigned isFinal : 1;
+
+    /// Whether the "isIUO" bit" has been computed yet.
+    unsigned isIUOComputed : 1;
+
+    /// Whether this declaration produces an implicitly unwrapped
+    /// optional result.
+    unsigned isIUO : 1;
   } LazySemanticInfo = { };
 
   friend class OverriddenDeclsRequest;
   friend class IsObjCRequest;
   friend class IsFinalRequest;
   friend class IsDynamicRequest;
+  friend class IsImplicitlyUnwrappedOptionalRequest;
 
 protected:
   ValueDecl(DeclKind K,
@@ -2686,6 +2694,21 @@ class ValueDecl : public Decl {
   /// Returns true if this decl can be found by id-style dynamic lookup.
   bool canBeAccessedByDynamicLookup() const;
 
+  /// Returns true if this declaration has an implicitly unwrapped optional
+  /// result. The precise meaning depends on the declaration kind:
+  /// - for properties, the value is IUO
+  /// - for subscripts, the element type is IUO
+  /// - for functions, the result type is IUO
+  /// - for constructors, the failability kind is IUO
+  bool isImplicitlyUnwrappedOptional() const;
+
+  /// Should only be set on imported and deserialized declarations; parsed
+  /// declarations compute this lazily via a request.
+  void setImplicitlyUnwrappedOptional(bool isIUO) {
+    LazySemanticInfo.isIUOComputed = 1;
+    LazySemanticInfo.isIUO = isIUO;
+  }
+
   /// Returns the protocol requirements that this decl conforms to.
   ArrayRef<ValueDecl *>
   getSatisfiedProtocolRequirements(bool Sorted = false) const;
@@ -3198,19 +3221,6 @@ class AssociatedTypeDecl : public AbstractTypeParamDecl {
 
 class MemberLookupTable;
 class ConformanceLookupTable;
-
-/// Kinds of optional types.
-enum OptionalTypeKind : unsigned {
-  /// The type is not an optional type.
-  OTK_None = 0,
-
-  /// The type is Optional<T>.
-  OTK_Optional,
-
-  /// The type is ImplicitlyUnwrappedOptional<T>.
-  OTK_ImplicitlyUnwrappedOptional
-};
-enum { NumOptionalTypeKinds = 2 };
 
 // Kinds of pointer types.
 enum PointerTypeKind : unsigned {
@@ -6495,7 +6505,7 @@ class ConstructorDecl : public AbstractFunctionDecl {
 
 public:
   ConstructorDecl(DeclName Name, SourceLoc ConstructorLoc, 
-                  OptionalTypeKind Failability, SourceLoc FailabilityLoc,
+                  bool Failable, SourceLoc FailabilityLoc,
                   bool Throws, SourceLoc ThrowsLoc,
                   ParameterList *BodyParams,
                   GenericParamList *GenericParams, 
@@ -6595,9 +6605,9 @@ class ConstructorDecl : public AbstractFunctionDecl {
     llvm_unreachable("bad CtorInitializerKind");
   }
 
-  /// Determine the failability of the initializer.
-  OptionalTypeKind getFailability() const {
-    return static_cast<OptionalTypeKind>(Bits.ConstructorDecl.Failability);
+  /// Determine if this is a failable initializer.
+  bool isFailable() const {
+    return Bits.ConstructorDecl.Failable;
   }
 
   /// Retrieve the location of the '!' or '?' in a failable initializer.

include/swift/AST/PrintOptions.h

@@ -292,8 +292,7 @@ struct PrintOptions {
   /// List of attribute kinds that should not be printed.
   std::vector<AnyAttrKind> ExcludeAttrList = {DAK_Transparent, DAK_Effects,
                                               DAK_FixedLayout,
-                                              DAK_ShowInInterface,
-                                              DAK_ImplicitlyUnwrappedOptional};
+                                              DAK_ShowInInterface};
 
   /// List of attribute kinds that should be printed exclusively.
   /// Empty means allow all.

include/swift/AST/TypeCheckRequests.h

@@ -1031,6 +1031,27 @@ class EmittedMembersRequest :
   void cacheResult(DeclRange value) const;
 };
 
+class IsImplicitlyUnwrappedOptionalRequest :
+    public SimpleRequest<IsImplicitlyUnwrappedOptionalRequest,
+                         bool(ValueDecl *),
+                         CacheKind::SeparatelyCached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  llvm::Expected<bool>
+  evaluate(Evaluator &evaluator, ValueDecl *value) const;
+
+public:
+  // Separate caching.
+  bool isCached() const { return true; }
+  Optional<bool> getCachedResult() const;
+  void cacheResult(bool value) const;
+};
+
 // Allow AnyValue to compare two Type values, even though Type doesn't
 // support ==.
 template<>

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -55,3 +55,4 @@ SWIFT_TYPEID(RequiresOpaqueModifyCoroutineRequest)
 SWIFT_TYPEID(IsAccessorTransparentRequest)
 SWIFT_TYPEID(SynthesizeAccessorRequest)
 SWIFT_TYPEID(EmittedMembersRequest)
+SWIFT_TYPEID(IsImplicitlyUnwrappedOptionalRequest)

include/swift/ClangImporter/ClangImporter.h

@@ -60,6 +60,19 @@ class TypeDecl;
 class VisibleDeclConsumer;
 enum class SelectorSplitKind;
 
+/// Kinds of optional types.
+enum OptionalTypeKind : unsigned {
+  /// The type is not an optional type.
+  OTK_None = 0,
+
+  /// The type is Optional<T>.
+  OTK_Optional,
+
+  /// The type is ImplicitlyUnwrappedOptional<T>.
+  OTK_ImplicitlyUnwrappedOptional
+};
+enum { NumOptionalTypeKinds = 2 };
+
 /// This interface is implemented by LLDB to serve as a fallback when Clang
 /// modules can't be imported from source in the debugger.
 ///

include/swift/Parse/Parser.h

@@ -1019,7 +1019,6 @@ class Parser {
   ParserStatus parseGetSet(ParseDeclOptions Flags,
                            GenericParamList *GenericParams,
                            ParameterList *Indices,
-                           TypeLoc ElementTy,
                            ParsedAccessors &accessors,
                            AbstractStorageDecl *storage,
                            SourceLoc StaticLoc);

include/swift/Serialization/ModuleFormat.h

@@ -52,7 +52,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 509; // [dynamic_lifetime] sil flag
+const uint16_t SWIFTMODULE_VERSION_MINOR = 511; // ctor failability change
 
 using DeclIDField = BCFixed<31>;
 
@@ -409,15 +409,6 @@ enum class AccessLevel : uint8_t {
 };
 using AccessLevelField = BCFixed<3>;
 
-// These IDs must \em not be renumbered or reordered without incrementing
-// the module version.
-enum class OptionalTypeKind : uint8_t {
-  None,
-  Optional,
-  ImplicitlyUnwrappedOptional
-};
-using OptionalTypeKindField = BCFixed<2>;
-
 // These IDs must \em not be renumbered or reordered without incrementing
 // the module version.
 enum class DeclNameKind: uint8_t {
@@ -1019,7 +1010,8 @@ namespace decls_block {
   using ConstructorLayout = BCRecordLayout<
     CONSTRUCTOR_DECL,
     DeclContextIDField, // context decl
-    OptionalTypeKindField,  // failability
+    BCFixed<1>,  // failable?
+    BCFixed<1>,  // IUO result?
     BCFixed<1>,  // implicit?
     BCFixed<1>,  // objc?
     BCFixed<1>,  // stub implementation?
@@ -1059,6 +1051,7 @@ namespace decls_block {
     ReadWriteImplKindField,   // read-write implementation
     AccessorCountField, // number of accessors
     TypeIDField,  // interface type
+    BCFixed<1>,   // IUO value?
     DeclIDField,  // overridden decl
     AccessLevelField, // access level
     AccessLevelField, // setter access, if applicable
@@ -1075,6 +1068,7 @@ namespace decls_block {
     DeclContextIDField,      // context decl
     ParamDeclSpecifierField, // specifier
     TypeIDField,             // interface type
+    BCFixed<1>,              // isIUO?
     BCFixed<1>,              // isVariadic?
     BCFixed<1>,              // isAutoClosure?
     DefaultArgumentField,    // default argument kind
@@ -1093,6 +1087,7 @@ namespace decls_block {
     BCFixed<1>,   // throws?
     GenericEnvironmentIDField, // generic environment
     TypeIDField,  // result interface type
+    BCFixed<1>,   // IUO result?
     DeclIDField,  // operator decl
     DeclIDField,  // overridden function
     BCVBR<5>,     // 0 for a simple name, otherwise the number of parameter name
@@ -1134,6 +1129,7 @@ namespace decls_block {
     BCFixed<1>,   // throws?
     GenericEnvironmentIDField, // generic environment
     TypeIDField,  // result interface type
+    BCFixed<1>,   // IUO result?
     DeclIDField,  // overridden function
     DeclIDField,  // AccessorStorageDecl
     AccessorKindField, // accessor kind
@@ -1220,6 +1216,7 @@ namespace decls_block {
     AccessorCountField, // number of accessors
     GenericEnvironmentIDField, // generic environment
     TypeIDField, // element interface type
+    BCFixed<1>,  // IUO element?
     DeclIDField, // overridden decl
     AccessLevelField, // access level
     AccessLevelField, // setter access, if applicable

lib/AST/ASTDumper.cpp

@@ -370,15 +370,6 @@ static StringRef getCtorInitializerKindString(CtorInitializerKind value) {
 
   llvm_unreachable("Unhandled CtorInitializerKind in switch.");
 }
-static StringRef getOptionalTypeKindString(OptionalTypeKind value) {
-  switch (value) {
-    case OTK_None: return "none";
-    case OTK_Optional: return "Optional";
-    case OTK_ImplicitlyUnwrappedOptional: return "ImplicitlyUnwrappedOptional";
-  }
-
-  llvm_unreachable("Unhandled OptionalTypeKind in switch.");
-}
 static StringRef getAssociativityString(Associativity value) {
   switch (value) {
     case Associativity::None: return "none";
@@ -1100,9 +1091,11 @@ namespace {
         PrintWithColorRAII(OS, DeclModifierColor) << " required";
       PrintWithColorRAII(OS, DeclModifierColor) << " "
         << getCtorInitializerKindString(CD->getInitKind());
-      if (CD->getFailability() != OTK_None)
+      if (CD->isFailable())
         PrintWithColorRAII(OS, DeclModifierColor) << " failable="
-          << getOptionalTypeKindString(CD->getFailability());
+          << (CD->isImplicitlyUnwrappedOptional()
+              ? "ImplicitlyUnwrappedOptional"
+              : "Optional");
       printAbstractFunctionDecl(CD);
       PrintWithColorRAII(OS, ParenthesisColor) << ')';
     }