Merge pull request #4617 from slavapestov/kill-canonical-mangling-signature

Kill canonical mangling signature

Author: slavapestov

include/swift/AST/ASTContext.h

@@ -230,10 +230,6 @@ class ASTContext {
 
   /// Cache of remapped types (useful for diagnostics).
   llvm::StringMap<Type> RemappedTypes;
-  
-  /// Cache for generic mangling signatures.
-  llvm::DenseMap<std::pair<GenericSignature*, ModuleDecl*>,
-                 CanGenericSignature> ManglingSignatures;
 
 private:
   /// \brief The current generation number, which reflects the number of
@@ -838,12 +834,6 @@ class ASTContext {
   ArchetypeBuilder *getOrCreateArchetypeBuilder(CanGenericSignature sig,
                                                 ModuleDecl *mod);
 
-  /// Set the stored archetype builder for the given canonical generic
-  /// signature and module.
-  void setArchetypeBuilder(CanGenericSignature sig,
-                           ModuleDecl *mod,
-                           std::unique_ptr<ArchetypeBuilder> builder);
-
   /// Retrieve the inherited name set for the given class.
   const InheritedNameSet *getAllPropertyNames(ClassDecl *classDecl,
                                               bool forInstance);

include/swift/AST/ArchetypeBuilder.h

@@ -63,15 +63,21 @@ class RequirementSource {
     /// The requirement was explicitly stated in the generic parameter
     /// clause.
     Explicit,
-    /// The requirement was explicitly stated in the generic parameter clause
-    /// but is redundant with some other requirement.
-    Redundant,
-    /// The requirement was part of a protocol requirement, e.g., an
-    /// inherited protocol or a requirement on an associated type.
-    Protocol,
-    /// 
-    /// The requirement was inferred from part of the signature.
+    /// The requirement was inferred from the function's parameter or
+    /// result types.
     Inferred,
+
+    /// The requirement was part of a protocol requirement on an
+    /// associated type.
+    ///
+    /// These are dropped when building the GenericSignature.
+    Protocol,
+
+    /// The requirement is redundant with some other requirement.
+    ///
+    /// These are dropped when building the GenericSignature.
+    Redundant,
+
     /// The requirement came from an outer scope.
     /// FIXME: eliminate this in favor of keeping requirement sources in 
     /// GenericSignatures, at least non-canonical ones?
@@ -242,9 +248,10 @@ class ArchetypeBuilder {
   /// \brief Add all of a generic signature's parameters and requirements.
   ///
   /// FIXME: Requirements from the generic signature are treated as coming from
-  /// an outer scope in order to avoid disturbing the AllDependentTypes.
-  /// Setting \c treatRequirementsAsExplicit to true disables this behavior.
-  void addGenericSignature(GenericSignature *sig, bool adoptArchetypes,
+  /// an outer scope. Setting \c treatRequirementsAsExplicit to true disables
+  /// this behavior.
+  void addGenericSignature(GenericSignature *sig,
+                           GenericEnvironment *genericEnv,
                            bool treatRequirementsAsExplicit = false);
 
   /// \brief Get a generic signature based on the provided complete list
@@ -342,13 +349,6 @@ class ArchetypeBuilder {
   using SameTypeRequirement
     = std::pair<PotentialArchetype *,
                 PointerUnion<Type, PotentialArchetype*>>;
-  
-  /// Retrieve the set of same-type requirements that apply to the potential
-  /// archetypes known to this builder.
-  ArrayRef<SameTypeRequirement> getSameTypeRequirements() const;
-
-  // FIXME: Compute the set of 'extra' witness tables needed to express this
-  // requirement set.
 
   /// \brief Dump all of the requirements, both specified and inferred.
   LLVM_ATTRIBUTE_DEPRECATED(
@@ -617,15 +617,15 @@ class ArchetypeBuilder::PotentialArchetype {
   }
 
   void setIsRecursive() { IsRecursive = true; }
-  bool isRecursive() { return IsRecursive; }
+  bool isRecursive() const { return IsRecursive; }
 
-  bool isInvalid() { return Invalid; }
+  bool isInvalid() const { return Invalid; }
 
   void setInvalid() { Invalid = true; }
 
   /// Determine whether this archetype was renamed due to typo
   /// correction. If so, \c getName() retrieves the new name.
-  bool wasRenamed() { return Renamed; }
+  bool wasRenamed() const { return Renamed; }
 
   /// Note that this potential archetype was renamed (due to typo
   /// correction), providing the new name.
@@ -636,7 +636,7 @@ class ArchetypeBuilder::PotentialArchetype {
 
   /// Whether this potential archetype makes a better archetype anchor than
   /// the given archetype anchor.
-  bool isBetterArchetypeAnchor(PotentialArchetype *other);
+  bool isBetterArchetypeAnchor(PotentialArchetype *other) const;
 
   void dump(llvm::raw_ostream &Out, SourceManager *SrcMgr,
             unsigned Indent);

include/swift/AST/DiagnosticsSema.def

@@ -1333,8 +1333,8 @@ NOTE(no_witnesses_type,none,
      "protocol requires nested type %0; do you want to add it?", (Identifier))
 NOTE(default_associated_type_req_fail,none,
      "default type %0 for associated type %1 (from protocol %2) "
-     "does not conform to %3",
-     (Type, DeclName, Type, Type))
+     "does not %select{inherit from|conform to}4 %3",
+     (Type, DeclName, Type, Type, bool))
 ERROR(associated_type_access,none,
       "associated type in "
       "%select{PRIVATE|a fileprivate|an internal|a public}0 protocol uses "
@@ -1347,8 +1347,8 @@ NOTE(bad_associated_type_deduction,none,
      (DeclName, DeclName))
 NOTE(associated_type_deduction_witness_failed,none,
      "inferred type %1 (by matching requirement %0) is invalid: "
-     "does not conform to %2",
-     (DeclName, Type, DeclName))
+     "does not %select{inherit from|conform to}3 %2",
+     (DeclName, Type, DeclName, bool))
 NOTE(ambiguous_associated_type_deduction,none,
      "ambiguous inference of associated type %0: %1 vs. %2",
      (DeclName, Type, Type))
@@ -1406,7 +1406,8 @@ NOTE(protocol_witness_not_objc,none,
 NOTE(protocol_witness_type,none,
      "possibly intended match", ())
 NOTE(protocol_witness_nonconform_type,none,
-     "possibly intended match %0 does not conform to %1", (Type, Type))
+     "possibly intended match %0 does not "
+     "%select{inherit from|conform to}2 %1", (Type, Type, bool))
 
 NOTE(protocol_requirement_here,none,
      "requirement %0 declared here", (DeclName))

include/swift/AST/GenericEnvironment.h

@@ -69,6 +69,8 @@ class GenericEnvironment final {
 
   ArrayRef<Substitution>
   getForwardingSubstitutions(ModuleDecl *M, GenericSignature *sig) const;
+
+  void dump() const;
 };
 
 } // end namespace swift

include/swift/AST/GenericSignature.h

@@ -28,6 +28,9 @@ namespace swift {
 class ArchetypeBuilder;
 class ProtocolType;
 
+using TypeConformanceMap
+  = llvm::DenseMap<TypeBase *, ArrayRef<ProtocolConformanceRef>>;
+
 /// Iterator that walks the generic parameter types declared in a generic
 /// signature and their dependent members.
 class GenericSignatureWitnessIterator {
@@ -171,15 +174,27 @@ class GenericSignature final : public llvm::FoldingSetNode,
   /// the order of generic parameters in getGenericParams().
   TypeSubstitutionMap getSubstitutionMap(ArrayRef<Substitution> args) const;
 
+  /// Variant of the above that also returns conformances.
+  void getSubstitutionMap(ArrayRef<Substitution> subs,
+                          TypeSubstitutionMap &subMap,
+                          TypeConformanceMap &conformanceMap) const;
+
   using LookupConformanceFn =
-      llvm::function_ref<ProtocolConformanceRef(Type, ProtocolType *)>;
+      llvm::function_ref<ProtocolConformanceRef(CanType, Type, ProtocolType *)>;
 
   /// Build an array of substitutions from an interface type substitution map,
   /// using the given function to look up conformances.
   void getSubstitutions(ModuleDecl &mod,
-                        const TypeSubstitutionMap &subs,
+                        const TypeSubstitutionMap &subMap,
                         LookupConformanceFn lookupConformance,
-                        SmallVectorImpl<Substitution> &result);
+                        SmallVectorImpl<Substitution> &result) const;
+
+  /// Build an array of substitutions from an interface type substitution map,
+  /// using the given function to look up conformances.
+  void getSubstitutions(ModuleDecl &mod,
+                        const TypeSubstitutionMap &subMap,
+                        const TypeConformanceMap &conformanceMap,
+                        SmallVectorImpl<Substitution> &result) const;
 
   /// Return a range that iterates through first all of the generic parameters
   /// of the signature, followed by all of their recursive member types exposed
@@ -195,16 +210,6 @@ class GenericSignature final : public llvm::FoldingSetNode,
 
   /// Canonicalize the components of a generic signature.
   CanGenericSignature getCanonicalSignature() const;
-  
-  /// Canonicalize a generic signature down to its essential requirements,
-  /// for mangling purposes.
-  ///
-  /// TODO: This is what getCanonicalSignature() ought to do, but currently
-  /// does not due to former implementation dependencies on
-  /// 'getAllDependentTypes' order matching 'getAllArchetypes' order of a
-  /// generic param list. Now that 'getAllArchetypes' is gone, we might
-  /// be able to move forward here.
-  CanGenericSignature getCanonicalManglingSignature(ModuleDecl &M) const;
 
   /// Uniquing for the ASTContext.
   void Profile(llvm::FoldingSetNodeID &ID) {

include/swift/AST/Module.h

@@ -952,7 +952,7 @@ class SourceFile final : public FileUnit {
                                              SourceLoc diagLoc = {});
   /// @}
 
-  ReferencedNameTracker *getReferencedNameTracker() {
+  ReferencedNameTracker *getReferencedNameTracker() const {
     return ReferencedNames;
   }
   void setReferencedNameTracker(ReferencedNameTracker *Tracker) {

include/swift/AST/ProtocolConformance.h

@@ -296,7 +296,6 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance {
   /// applies to the substituted type.
   ProtocolConformance *subst(ModuleDecl *module,
                              Type substType,
-                             ArrayRef<Substitution> subs,
                              TypeSubstitutionMap &subMap,
                              ArchetypeConformanceMap &conformanceMap);
 };

include/swift/AST/Requirement.h

@@ -74,6 +74,8 @@ class Requirement {
   Type getSecondType() const {
     return SecondType;
   }
+
+  void dump() const;
 };
 
 } // end namespace swift

include/swift/AST/Substitution.h

@@ -71,13 +71,12 @@ class Substitution {
                      GenericEnvironment *env,
                      ArrayRef<Substitution> subs) const;
 
-private:
-  friend class ProtocolConformance;
-  
   Substitution subst(ModuleDecl *module,
-                     ArrayRef<Substitution> subs,
                      TypeSubstitutionMap &subMap,
                      ArchetypeConformanceMap &conformanceMap) const;
+
+private:
+  friend class ProtocolConformance;
 };
 
 void dump(const ArrayRef<Substitution> &subs);

include/swift/AST/Types.h

@@ -636,6 +636,19 @@ class alignas(1 << TypeAlignInBits) TypeBase {
   /// a type's subclass.
   bool isExactSuperclassOf(Type ty, LazyResolver *resolver);
 
+  /// \brief Get the substituted base class type, starting from a base class
+  /// declaration and a substituted derived class type.
+  ///
+  /// For example, given the following declarations:
+  ///
+  /// class A<T, U> {}
+  /// class B<V> : A<Int, V> {}
+  /// class C<X, Y> : B<Y> {}
+  ///
+  /// Calling `C<String, NSObject>`->getSuperclassForDecl(`A`) will return
+  /// `A<Int, NSObject>`.
+  Type getSuperclassForDecl(const ClassDecl *classDecl, LazyResolver *resolver);
+
   /// \brief True if this type is the superclass of another type, or a generic
   /// type that could be bound to the superclass.
   ///