Merge pull request #38382 from slavapestov/encapsulate-lookup-nested-type

slavapestov · web-flow · commit 7e854637923d · 2021-07-14T02:51:54.000-04:00
Introduce GenericSignature::lookupNestedType() to further hide GenericSignatureBuilder
diff --git a/include/swift/AST/GenericSignature.h b/include/swift/AST/GenericSignature.h
@@ -389,6 +389,9 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   ConformanceAccessPath getConformanceAccessPath(Type type,
                                                  ProtocolDecl *protocol) const;
 
+  /// Lookup a nested type with the given name within this type parameter.
+  TypeDecl *lookupNestedType(Type type, Identifier name) const;
+
   /// Get the ordinal of a generic parameter in this generic signature.
   ///
   /// For example, if you have a generic signature for a nested context like:
diff --git a/lib/AST/GenericSignature.cpp b/lib/AST/GenericSignature.cpp
@@ -795,6 +795,21 @@ GenericSignatureImpl::getConformanceAccessPath(Type type,
       type, protocol, this);
 }
 
+TypeDecl *
+GenericSignatureImpl::lookupNestedType(Type type, Identifier name) const {
+  assert(type->isTypeParameter());
+
+  auto *builder = getGenericSignatureBuilder();
+  auto equivClass =
+    builder->resolveEquivalenceClass(
+                                type,
+                                ArchetypeResolutionKind::CompleteWellFormed);
+  if (!equivClass)
+    return nullptr;
+
+  return equivClass->lookupNestedType(*builder, name);
+}
+
 unsigned GenericParamKey::findIndexIn(
                       TypeArrayView<GenericTypeParamType> genericParams) const {
   // For depth 0, we have random access. We perform the extra checking so that
diff --git a/lib/ClangImporter/ImportType.cpp b/lib/ClangImporter/ImportType.cpp
@@ -23,8 +23,8 @@
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticsClangImporter.h"
 #include "swift/AST/ExistentialLayout.h"
-#include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
+#include "swift/AST/GenericParamList.h"
+#include "swift/AST/GenericSignature.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/ParameterList.h"
diff --git a/lib/SIL/IR/SILFunctionType.cpp b/lib/SIL/IR/SILFunctionType.cpp
@@ -23,7 +23,6 @@
 #include "swift/AST/DiagnosticsSIL.h"
 #include "swift/AST/ForeignInfo.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/ModuleLoader.h"
 #include "swift/AST/ProtocolConformance.h"
diff --git a/lib/Sema/TypeCheckDeclPrimary.cpp b/lib/Sema/TypeCheckDeclPrimary.cpp
@@ -35,7 +35,6 @@
 #include "swift/AST/Expr.h"
 #include "swift/AST/ForeignErrorConvention.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/NameLookupRequests.h"
diff --git a/lib/Sema/TypeCheckGeneric.cpp b/lib/Sema/TypeCheckGeneric.cpp
@@ -19,7 +19,6 @@
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/TypeCheckRequests.h"
diff --git a/lib/Sema/TypeCheckType.cpp b/lib/Sema/TypeCheckType.cpp
@@ -29,7 +29,6 @@
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/ForeignErrorConvention.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/GenericSignatureBuilder.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/PrettyStackTrace.h"
@@ -75,8 +74,7 @@ TypeResolution::forInterface(DeclContext *dc, TypeResolutionOptions options,
                              HandlePlaceholderTypeReprFn placeholderHandler) {
   TypeResolution result(dc, TypeResolutionStage::Interface, options,
                         unboundTyOpener, placeholderHandler);
-  result.complete.genericSig = dc->getGenericSignatureOfContext();
-  result.complete.builder = nullptr;
+  result.genericSig = dc->getGenericSignatureOfContext();
   return result;
 }
 
@@ -102,32 +100,22 @@ TypeResolution::forContextual(DeclContext *dc, GenericEnvironment *genericEnv,
 TypeResolution TypeResolution::withOptions(TypeResolutionOptions opts) const {
   TypeResolution result(dc, stage, opts, unboundTyOpener, placeholderHandler);
   result.genericEnv = genericEnv;
-  result.complete = complete;
+  result.genericSig = genericSig;
   return result;
 }
 
 ASTContext &TypeResolution::getASTContext() const {
   return dc->getASTContext();
 }
 
-GenericSignatureBuilder *TypeResolution::getGenericSignatureBuilder() const {
-  assert(stage == TypeResolutionStage::Interface);
-  if (!complete.builder) {
-    auto genericSig = getGenericSignature();
-    complete.builder = genericSig->getGenericSignatureBuilder();
-  }
-
-  return complete.builder;
-}
-
 GenericSignature TypeResolution::getGenericSignature() const {
   switch (stage) {
   case TypeResolutionStage::Contextual:
     return dc->getGenericSignatureOfContext();
 
   case TypeResolutionStage::Interface:
-    if (complete.genericSig)
-      return complete.genericSig;
+    if (genericSig)
+      return genericSig;
 
     return dc->getGenericSignatureOfContext();
 
@@ -197,22 +185,13 @@ Type TypeResolution::resolveDependentMemberType(
   if (!genericSig)
     return ErrorType::get(baseTy);
 
-  auto builder = getGenericSignatureBuilder();
-  auto baseEquivClass =
-    builder->resolveEquivalenceClass(
-                                baseTy,
-                                ArchetypeResolutionKind::CompleteWellFormed);
-  if (!baseEquivClass)
-    return ErrorType::get(baseTy);
-
-  ASTContext &ctx = baseTy->getASTContext();
-
   // Look for a nested type with the given name.
-  if (auto nestedType =
-          baseEquivClass->lookupNestedType(*builder, refIdentifier)) {
+  if (auto nestedType = genericSig->lookupNestedType(baseTy, refIdentifier)) {
     // Record the type we found.
     ref->setValue(nestedType, nullptr);
   } else {
+    ASTContext &ctx = DC->getASTContext();
+
     // Resolve the base to a potential archetype.
     // Perform typo correction.
     TypoCorrectionResults corrections(ref->getNameRef(), ref->getNameLoc());
@@ -258,13 +237,6 @@ Type TypeResolution::resolveDependentMemberType(
     return DependentMemberType::get(baseTy, assocType);
   }
 
-  // Otherwise, the nested type comes from a concrete type,
-  // or it's a typealias declared in protocol or protocol extension.
-  // Substitute the base type into it.
-
-  // Make sure that base type didn't get replaced along the way.
-  assert(baseTy->isTypeParameter());
-
   // There are two situations possible here:
   //
   // 1. Member comes from the protocol, which means that it has been
@@ -280,9 +252,12 @@ Type TypeResolution::resolveDependentMemberType(
   // end up using incorrect generic signature while attempting to form
   // a substituted type for the member we found.
   if (!concrete->getDeclContext()->getSelfProtocolDecl()) {
-    baseTy = baseEquivClass->concreteType ? baseEquivClass->concreteType
-                                          : baseEquivClass->superclass;
-    assert(baseTy);
+    if (auto concreteTy = genericSig->getConcreteType(baseTy))
+      baseTy = concreteTy;
+    else {
+      baseTy = genericSig->getSuperclassBound(baseTy);
+      assert(baseTy);
+    }
   }
 
   return TypeChecker::substMemberTypeWithBase(DC->getParentModule(), concrete,
@@ -305,16 +280,12 @@ Type TypeResolution::resolveSelfAssociatedType(Type baseTy,
   }
 
   assert(stage == TypeResolutionStage::Interface);
-  auto builder = getGenericSignatureBuilder();
-  auto baseEquivClass =
-    builder->resolveEquivalenceClass(
-                                baseTy,
-                                ArchetypeResolutionKind::CompleteWellFormed);
-  if (!baseEquivClass)
+  auto genericSig = getGenericSignature();
+  if (!genericSig)
     return ErrorType::get(baseTy);
 
   // Look for a nested type with the given name.
-  auto nestedType = baseEquivClass->lookupNestedType(*builder, name);
+  auto nestedType = genericSig->lookupNestedType(baseTy, name);
   assert(nestedType);
 
   // If the nested type has been resolved to an associated type, use it.
@@ -327,9 +298,12 @@ Type TypeResolution::resolveSelfAssociatedType(Type baseTy,
     // extension.
     //
     // Get the superclass of the 'Self' type parameter.
-    baseTy = (baseEquivClass->concreteType
-              ? baseEquivClass->concreteType
-              : baseEquivClass->superclass);
+    if (auto concreteTy = genericSig->getConcreteType(baseTy))
+      baseTy = concreteTy;
+    else {
+      baseTy = genericSig->getSuperclassBound(baseTy);
+      assert(baseTy);
+    }
     assert(baseTy);
   }
 
@@ -925,12 +899,13 @@ Type TypeResolution::applyUnboundGenericArguments(
     }
 
     skipRequirementsCheck |= parentTy->hasTypeVariable();
-  } else if (auto genericEnv =
-                 decl->getDeclContext()->getGenericEnvironmentOfContext()) {
-    auto genericSig = genericEnv->getGenericSignature();
+  } else if (auto genericSig =
+                 decl->getDeclContext()->getGenericSignatureOfContext()) {
     for (auto gp : genericSig->getGenericParams()) {
       subs[gp->getCanonicalType()->castTo<GenericTypeParamType>()] =
-          (usesArchetypes() ? genericEnv->mapTypeIntoContext(gp) : gp);
+          (usesArchetypes()
+           ? genericSig->getGenericEnvironment()->mapTypeIntoContext(gp)
+           : gp);
     }
   }
 
diff --git a/lib/Sema/TypeCheckType.h b/lib/Sema/TypeCheckType.h
@@ -28,7 +28,6 @@ class TypeRepr;
 class ComponentIdentTypeRepr;
 class GenericEnvironment;
 class GenericSignature;
-class GenericSignatureBuilder;
 
 /// Flags that describe the context of type checking a pattern or
 /// type.
@@ -297,30 +296,20 @@ class TypeResolution {
   HandlePlaceholderTypeReprFn placeholderHandler;
 
 private:
-  union {
-    /// The generic environment used to map to archetypes.
-    GenericEnvironment *genericEnv;
+  /// The generic environment used to map to archetypes.
+  GenericEnvironment *genericEnv;
 
-    /// The generic signature
-    struct {
-      /// The generic signature to use for type resolution.
-      GenericSignature genericSig;
-
-      /// The generic signature builder that will answer queries about
-      /// generic types.
-      mutable GenericSignatureBuilder *builder;
-    } complete;
-  };
+  /// The generic signature to use for type resolution.
+  GenericSignature genericSig;
 
   TypeResolution(DeclContext *dc, TypeResolutionStage stage,
                  TypeResolutionOptions options,
                  OpenUnboundGenericTypeFn unboundTyOpener,
                  HandlePlaceholderTypeReprFn placeholderHandler)
       : dc(dc), stage(stage), options(options),
         unboundTyOpener(unboundTyOpener),
-        placeholderHandler(placeholderHandler) {}
-
-  GenericSignatureBuilder *getGenericSignatureBuilder() const;
+        placeholderHandler(placeholderHandler),
+        genericEnv(nullptr) {}
 
   /// Retrieves the generic signature for the context, or NULL if there is
   /// no generic signature to resolve types.
