Merge pull request #12075 from apple/revert-12062-make-fewer-gsbs

Revert "Create fewer generic signature builders"

Author: DougGregor

include/swift/AST/ASTContext.h

@@ -846,16 +846,6 @@ class ASTContext {
   /// not necessarily loaded.
   void getVisibleTopLevelClangModules(SmallVectorImpl<clang::Module*> &Modules) const;
 
-private:
-  /// Register the given generic signature builder to be used as the canonical
-  /// generic signature builder for the given signature, if we don't already
-  /// have one.
-  void registerGenericSignatureBuilder(GenericSignature *sig,
-                                       ModuleDecl &module,
-                                       GenericSignatureBuilder &&builder);
-  friend class GenericSignatureBuilder;
-
-public:
   /// Retrieve or create the stored generic signature builder for the given
   /// canonical generic signature and module.
   GenericSignatureBuilder *getOrCreateGenericSignatureBuilder(CanGenericSignature sig,

include/swift/AST/Decl.h

@@ -4591,7 +4591,7 @@ class ParamDecl : public VarDecl {
   /// Clone constructor, allocates a new ParamDecl identical to the first.
   /// Intentionally not defined as a typical copy constructor to avoid
   /// accidental copies.
-  ParamDecl(ParamDecl *PD, bool withTypes);
+  ParamDecl(ParamDecl *PD);
 
   /// Retrieve the argument (API) name for this function parameter.
   Identifier getArgumentName() const { return ArgumentName; }

include/swift/AST/GenericSignatureBuilder.h

@@ -215,14 +215,6 @@ class GenericSignatureBuilder {
     /// a superclass requirement.
     bool isConformanceSatisfiedBySuperclass(ProtocolDecl *proto) const;
 
-    /// Lookup a nested type with the given name within this equivalence
-    /// class.
-    ///
-    /// \param otherConcreteTypes If non-null, will be filled in the all of the
-    /// concrete types we found (other than the result) with the same name.
-    TypeDecl *lookupNestedType(Identifier name,
-                               SmallVectorImpl<TypeDecl *> *otherConcreteTypes);
-
     /// Dump a debugging representation of this equivalence class.
     void dump(llvm::raw_ostream &out) const;
 
@@ -240,17 +232,6 @@ class GenericSignatureBuilder {
       /// anchor was cached.
       unsigned numMembers;
     } archetypeAnchorCache;
-
-    /// Describes a cached nested type.
-    struct CachedNestedType {
-      unsigned numConformancesPresent;
-      CanType superclassPresent;
-      llvm::TinyPtrVector<TypeDecl *> types;
-    };
-
-    /// Cached nested-type information, which contains the best declaration
-    /// for a given name.
-    llvm::SmallDenseMap<Identifier, CachedNestedType> nestedTypeNameCache;
   };
 
   friend class RequirementSource;
@@ -541,6 +522,9 @@ class GenericSignatureBuilder {
   /// \brief Add all of a generic signature's parameters and requirements.
   void addGenericSignature(GenericSignature *sig);
 
+  /// \brief Build the generic signature.
+  GenericSignature *getGenericSignature();
+
   /// Infer requirements from the given type, recursively.
   ///
   /// This routine infers requirements from a type that occurs within the
@@ -574,14 +558,11 @@ class GenericSignatureBuilder {
   /// \brief Finalize the set of requirements and compute the generic
   /// signature.
   ///
-  /// After this point, one cannot introduce new requirements, and the
-  /// generic signature builder no longer has valid state.
+  /// After this point, one cannot introduce new requirements.
   GenericSignature *computeGenericSignature(
-                      ModuleDecl &module,
                       SourceLoc loc,
-                      bool allowConcreteGenericParams = false) &&;
+                      bool allowConcreteGenericParams = false);
 
-private:
   /// Finalize the set of requirements, performing any remaining checking
   /// required before generating archetypes.
   ///
@@ -591,7 +572,6 @@ class GenericSignatureBuilder {
                 ArrayRef<GenericTypeParamType *> genericParams,
                 bool allowConcreteGenericParams=false);
 
-public:
   /// Process any delayed requirements that can be handled now.
   void processDelayedRequirements();
 
@@ -1495,12 +1475,6 @@ class GenericSignatureBuilder::PotentialArchetype {
     return pa->parentOrBuilder.get<GenericSignatureBuilder *>();
   }
 
-  // Replace the generic signature builder.
-  void replaceBuilder(GenericSignatureBuilder *builder) {
-    assert(parentOrBuilder.is<GenericSignatureBuilder *>());
-    parentOrBuilder = builder;
-  }
-
   friend class GenericSignatureBuilder;
   friend class GenericSignature;
 
@@ -1516,12 +1490,6 @@ class GenericSignatureBuilder::PotentialArchetype {
     return parentOrBuilder.dyn_cast<PotentialArchetype *>();
   }
 
-  /// Retrieve the type declaration to which this nested type was resolved.
-  TypeDecl *getResolvedType() const {
-    assert(getParent() && "Not an associated type");
-    return identifier.assocTypeOrConcrete;
-  }
-
   /// Retrieve the associated type to which this potential archetype
   /// has been resolved.
   AssociatedTypeDecl *getResolvedAssociatedType() const {
@@ -1664,8 +1632,13 @@ class GenericSignatureBuilder::PotentialArchetype {
                                     ArchetypeResolutionKind kind,
                                     GenericSignatureBuilder &builder);
 
-  /// \brief Retrieve (or create) a nested type with a known type.
-  PotentialArchetype *getNestedType(TypeDecl *type,
+  /// \brief Retrieve (or create) a nested type with a known associated type.
+  PotentialArchetype *getNestedType(AssociatedTypeDecl *assocType,
+                                    GenericSignatureBuilder &builder);
+
+  /// \brief Retrieve (or create) a nested type with a known concrete type
+  /// declaration.
+  PotentialArchetype *getNestedType(TypeDecl *concreteDecl,
                                     GenericSignatureBuilder &builder);
 
   /// \brief Retrieve (or create) a nested type that is the current best
@@ -1685,8 +1658,8 @@ class GenericSignatureBuilder::PotentialArchetype {
   /// type or typealias of the given protocol, unless the \c kind implies that
   /// a potential archetype should not be created if it's missing.
   PotentialArchetype *updateNestedTypeForConformance(
-                        TypeDecl *type,
-                        ArchetypeResolutionKind kind);
+                      PointerUnion<AssociatedTypeDecl *, TypeDecl *> type,
+                      ArchetypeResolutionKind kind);
 
   /// Update the named nested type when we know this type conforms to the given
   /// protocol.

include/swift/AST/ParameterList.h

@@ -128,15 +128,9 @@ class alignas(ParamDecl *) ParameterList final :
     Implicit = 0x01,
     /// The cloned pattern is for an inherited constructor; mark default
     /// arguments as inherited, and mark unnamed arguments as named.
-    Inherited = 0x02,
-    /// The cloned pattern will strip type information.
-    WithoutTypes = 0x04,
+    Inherited = 0x02
   };
-
-  friend OptionSet<CloneFlags> operator|(CloneFlags flag1, CloneFlags flag2) {
-    return OptionSet<CloneFlags>(flag1) | flag2;
-  }
-
+  
   /// Make a duplicate copy of this parameter list.  This allocates copies of
   /// the ParamDecls, so they can be reparented into a new DeclContext.
   ParameterList *clone(const ASTContext &C,

lib/AST/ASTContext.cpp

@@ -43,7 +43,6 @@
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Allocator.h"
@@ -53,12 +52,6 @@
 
 using namespace swift;
 
-#define DEBUG_TYPE "ASTContext"
-STATISTIC(NumRegisteredGenericSignatureBuilders,
-          "# of generic signature builders successfully registered");
-STATISTIC(NumRegisteredGenericSignatureBuildersAlready,
-          "# of generic signature builders already registered");
-
 /// Define this to 1 to enable expensive assertions of the
 /// GenericSignatureBuilder.
 #define SWIFT_GSB_EXPENSIVE_ASSERTIONS 0
@@ -1430,22 +1423,6 @@ void ASTContext::getVisibleTopLevelClangModules(
     collectAllModules(Modules);
 }
 
-void ASTContext::registerGenericSignatureBuilder(
-                                       GenericSignature *sig,
-                                       ModuleDecl &module,
-                                       GenericSignatureBuilder &&builder) {
-  auto canSig = sig->getCanonicalSignature();
-  auto known = Impl.GenericSignatureBuilders.find({canSig, &module});
-  if (known != Impl.GenericSignatureBuilders.end()) {
-    ++NumRegisteredGenericSignatureBuildersAlready;
-    return;
-  }
-
-  ++NumRegisteredGenericSignatureBuilders;
-  Impl.GenericSignatureBuilders[{canSig, &module}] =
-    llvm::make_unique<GenericSignatureBuilder>(std::move(builder));
-}
-
 GenericSignatureBuilder *ASTContext::getOrCreateGenericSignatureBuilder(
                                                       CanGenericSignature sig,
                                                       ModuleDecl *mod) {
@@ -4614,7 +4591,7 @@ CanGenericSignature ASTContext::getExistentialSignature(CanType existential,
     GenericSignatureBuilder::FloatingRequirementSource::forAbstract();
   builder.addRequirement(requirement, source, nullptr);
 
-  CanGenericSignature genericSig(std::move(builder).computeGenericSignature(*mod, SourceLoc()));
+  CanGenericSignature genericSig(builder.computeGenericSignature(SourceLoc()));
 
   auto result = Impl.ExistentialSignatures.insert(
     std::make_pair(existential, genericSig));

lib/AST/Builtins.cpp

@@ -491,9 +491,7 @@ namespace {
         Builder.addGenericParameter(gp);
       }
 
-      auto GenericSig =
-        std::move(Builder).computeGenericSignature(*ctx.TheBuiltinModule,
-                                                   SourceLoc());
+      auto GenericSig = Builder.computeGenericSignature(SourceLoc());
       GenericEnv = GenericSig->createGenericEnvironment(*ctx.TheBuiltinModule);
     }
 

lib/AST/Decl.cpp

@@ -3419,8 +3419,7 @@ void ProtocolDecl::computeRequirementSignature() {
          nullptr);
 
   // Compute and record the signature.
-  auto requirementSig =
-    std::move(builder).computeGenericSignature(*module, SourceLoc());
+  auto requirementSig = builder.computeGenericSignature(SourceLoc());
   RequirementSignature = requirementSig->getRequirements().data();
   assert(RequirementSignature != nullptr);
   NumRequirementsInSignature = requirementSig->getRequirements().size();
@@ -4218,22 +4217,18 @@ ParamDecl::ParamDecl(Specifier specifier,
 
 /// Clone constructor, allocates a new ParamDecl identical to the first.
 /// Intentionally not defined as a copy constructor to avoid accidental copies.
-ParamDecl::ParamDecl(ParamDecl *PD, bool withTypes)
+ParamDecl::ParamDecl(ParamDecl *PD)
   : VarDecl(DeclKind::Param, /*IsStatic*/false, PD->getSpecifier(),
             /*IsCaptureList*/false, PD->getNameLoc(), PD->getName(),
-            PD->hasType() && withTypes? PD->getType() : Type(),
-            PD->getDeclContext()),
+            PD->hasType() ? PD->getType() : Type(), PD->getDeclContext()),
     ArgumentName(PD->getArgumentName()),
     ArgumentNameLoc(PD->getArgumentNameLoc()),
     SpecifierLoc(PD->getSpecifierLoc()),
     DefaultValueAndIsVariadic(nullptr, PD->DefaultValueAndIsVariadic.getInt()),
     IsTypeLocImplicit(PD->IsTypeLocImplicit),
     defaultArgumentKind(PD->defaultArgumentKind) {
   typeLoc = PD->getTypeLoc().clone(PD->getASTContext());
-  if (!withTypes && typeLoc.getTypeRepr())
-    typeLoc.setType(Type());
-
-  if (withTypes && PD->hasInterfaceType())
+  if (PD->hasInterfaceType())
     setInterfaceType(PD->getInterfaceType());
 }