[NFC] AST: Requestify checkInheritanceClause.

Author: nate-chandler

include/swift/AST/Decl.h

@@ -561,7 +561,13 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     HasStubImplementation : 1
   );
 
-  SWIFT_INLINE_BITFIELD_EMPTY(TypeDecl, ValueDecl);
+  SWIFT_INLINE_BITFIELD(TypeDecl, ValueDecl, 1+1,
+    /// Whether the inheritance clause has been checked.
+    HasCheckedInheritanceClause : 1,
+
+    /// Whether the inheritance clause checked successfully.
+    HasValidInheritanceClause : 1
+  );
 
   SWIFT_INLINE_BITFIELD_FULL(GenericTypeParamDecl, TypeDecl, 16+16+1+1,
     : NumPadBits,
@@ -774,7 +780,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     NumPathElements : 8
   );
 
-  SWIFT_INLINE_BITFIELD(ExtensionDecl, Decl, 4+1,
+  SWIFT_INLINE_BITFIELD(ExtensionDecl, Decl, 4+1+1+1,
     /// An encoding of the default and maximum access level for this extension.
     /// The value 4 corresponds to AccessLevel::Public
     ///
@@ -784,7 +790,13 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     DefaultAndMaxAccessLevel : 4,
 
     /// Whether there is are lazily-loaded conformances for this extension.
-    HasLazyConformances : 1
+    HasLazyConformances : 1,
+
+    /// Whether the inheritance clause has been checked.
+    HasCheckedInheritanceClause : 1,
+
+    /// Whether the inheritance clause checked successfully.
+    HasValidInheritanceClause : 1
   );
 
   SWIFT_INLINE_BITFIELD(IfConfigDecl, Decl, 1,
@@ -1819,6 +1831,17 @@ class ExtensionDecl final : public GenericContext, public Decl,
 
   void setInherited(ArrayRef<InheritedEntry> i) { Inherited = i; }
 
+  void setInheritanceClauseChecked(bool valid) {
+    assert(!Bits.ExtensionDecl.HasCheckedInheritanceClause);
+    Bits.ExtensionDecl.HasCheckedInheritanceClause = true;
+    Bits.ExtensionDecl.HasValidInheritanceClause = valid;
+  }
+
+  std::pair<bool, bool> hasCheckedInheritanceClause() const {
+    return {Bits.ExtensionDecl.HasCheckedInheritanceClause,
+            Bits.ExtensionDecl.HasValidInheritanceClause};
+  }
+
   bool hasDefaultAccessLevel() const {
     return Bits.ExtensionDecl.DefaultAndMaxAccessLevel != 0;
   }
@@ -3233,8 +3256,11 @@ class TypeDecl : public ValueDecl {
 protected:
   TypeDecl(DeclKind K, llvm::PointerUnion<DeclContext *, ASTContext *> context,
            Identifier name, SourceLoc NameLoc,
-           ArrayRef<InheritedEntry> inherited) :
-    ValueDecl(K, context, name, NameLoc), Inherited(inherited) {}
+           ArrayRef<InheritedEntry> inherited)
+      : ValueDecl(K, context, name, NameLoc), Inherited(inherited) {
+    Bits.TypeDecl.HasCheckedInheritanceClause = false;
+    Bits.TypeDecl.HasValidInheritanceClause = false;
+  }
 
   friend class InheritedTypes;
 
@@ -3257,6 +3283,17 @@ class TypeDecl : public ValueDecl {
 
   void setInherited(ArrayRef<InheritedEntry> i) { Inherited = i; }
 
+  void setInheritanceClauseChecked(bool valid) {
+    assert(!Bits.TypeDecl.HasCheckedInheritanceClause);
+    Bits.TypeDecl.HasCheckedInheritanceClause = true;
+    Bits.TypeDecl.HasValidInheritanceClause = valid;
+  }
+
+  std::pair<bool, bool> hasCheckedInheritanceClause() const {
+    return {Bits.TypeDecl.HasCheckedInheritanceClause,
+            Bits.TypeDecl.HasValidInheritanceClause};
+  }
+
   struct CanBeInvertible {
     /// Indicates how "strongly" a TypeDecl will conform to an invertible
     /// protocol. Supports inequality comparisons and casts to bool.

include/swift/AST/TypeCheckRequests.h

@@ -4866,6 +4866,7 @@ class ImportDeclRequest
   bool isCached() const { return true; }
 };
 
+
 class LifetimeDependenceInfoRequest
     : public SimpleRequest<LifetimeDependenceInfoRequest,
                            std::optional<LifetimeDependenceInfo>(
@@ -4885,6 +4886,31 @@ class LifetimeDependenceInfoRequest
   bool isCached() const { return true; }
 };
 
+/// Type check an inheritance clause.
+class InheritanceClauseRequest
+    : public SimpleRequest<
+          InheritanceClauseRequest,
+          ArrayRef<InheritedEntry>(
+              llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *>),
+          RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  ArrayRef<InheritedEntry>
+  evaluate(Evaluator &evaluator,
+           llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *>
+               declUnion) const;
+
+public:
+  // Cached in TypeDecl/ExtensionDecl.
+  bool isCached() const { return true; }
+  std::optional<ArrayRef<InheritedEntry>> getCachedResult() const;
+  void cacheResult(ArrayRef<InheritedEntry>) const;
+};
+
 #define SWIFT_TYPEID_ZONE TypeChecker
 #define SWIFT_TYPEID_HEADER "swift/AST/TypeCheckerTypeIDZone.def"
 #include "swift/Basic/DefineTypeIDZone.h"

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -205,6 +205,9 @@ SWIFT_REQUEST(TypeChecker, InheritedTypeRequest,
               Type(llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *>,
                    unsigned, TypeResolutionStage),
               SeparatelyCached, HasNearestLocation)
+SWIFT_REQUEST(TypeChecker, InheritanceClauseRequest,
+              evaluator::SideEffect(llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *>),
+              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InheritsSuperclassInitializersRequest,
               bool(ClassDecl *), SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InitKindRequest,

lib/AST/Decl.cpp

@@ -1686,6 +1686,8 @@ ExtensionDecl::ExtensionDecl(SourceLoc extensionLoc,
 {
   Bits.ExtensionDecl.DefaultAndMaxAccessLevel = 0;
   Bits.ExtensionDecl.HasLazyConformances = false;
+  Bits.ExtensionDecl.HasCheckedInheritanceClause = false;
+  Bits.ExtensionDecl.HasValidInheritanceClause = false;
   setTrailingWhereClause(trailingWhereClause);
 }
 

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -87,13 +87,34 @@ static Type containsParameterizedProtocolType(Type inheritedTy) {
   return Type();
 }
 
+static ArrayRef<InheritedEntry> checkInheritanceClauseEntries(
+    llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> declUnion) {
+  const Decl *decl = nullptr;
+  if (const auto *td = declUnion.dyn_cast<const TypeDecl *>()) {
+    decl = td;
+  } else {
+    decl = declUnion.get<const ExtensionDecl *>();
+  }
+  ASTContext &ctx = decl->getASTContext();
+  return evaluateOrDefault(ctx.evaluator, InheritanceClauseRequest{declUnion},
+                           {});
+}
+
+static void checkInheritanceClause(
+    llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> declUnion) {
+  auto entries = checkInheritanceClauseEntries(declUnion);
+  (void)entries;
+}
+
 /// Check the inheritance clause of a type declaration or extension thereof.
 ///
 /// This routine performs detailed checking of the inheritance clause of the
 /// given type or extension. It need only be called within the primary source
 /// file.
-static void checkInheritanceClause(
-    llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> declUnion) {
+ArrayRef<InheritedEntry> InheritanceClauseRequest::evaluate(
+    Evaluator &evaluator,
+    llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> declUnion)
+    const {
   auto inheritedTypes = InheritedTypes(declUnion);
   auto inheritedClause = inheritedTypes.getEntries();
   const ExtensionDecl *ext = nullptr;
@@ -109,7 +130,7 @@ static void checkInheritanceClause(
                  proto->getName())
           .highlight(SourceRange(inheritedClause.front().getSourceRange().Start,
                                  inheritedClause.back().getSourceRange().End));
-        return;
+        return {};
       }
     }
   } else {
@@ -341,6 +362,50 @@ static void checkInheritanceClause(
                    inheritedTy);
     // FIXME: Note pointing to the declaration 'inheritedTy' references?
   }
+  CheckSuppressions(declUnion, suppressedConformances, ctx).check();
+  return inheritedTypes.getEntries();
+}
+
+std::optional<ArrayRef<InheritedEntry>>
+InheritanceClauseRequest::getCachedResult() const {
+  auto declUnion = std::get<0>(getStorage());
+  if (const auto *td = declUnion.dyn_cast<const TypeDecl *>()) {
+    auto checking = td->hasCheckedInheritanceClause();
+    if (!checking.first)
+      return std::nullopt;
+    if (!checking.second)
+      return {{}};
+  } else {
+    auto *ed = declUnion.get<const ExtensionDecl *>();
+    auto checking = ed->hasCheckedInheritanceClause();
+    if (!checking.first)
+      return std::nullopt;
+    if (!checking.second)
+      return {{}};
+  }
+  return InheritedTypes(std::get<0>(getStorage())).getEntries();
+}
+
+void InheritanceClauseRequest::cacheResult(
+    ArrayRef<InheritedEntry> entries) const {
+  auto declUnion = std::get<0>(getStorage());
+  auto inheritanceClause = InheritedTypes(declUnion);
+  if (inheritanceClause.size() == 0) {
+    // Nothing to check, nothing to cache.
+    assert(entries.size() == 0);
+    return;
+  }
+  assert(entries.size() == 0 || entries.size() == inheritanceClause.size());
+  // It's valid if it has entries.
+  auto valid = entries.size() > 0;
+  if (const auto *td = declUnion.dyn_cast<const TypeDecl *>()) {
+    auto *mtd = const_cast<TypeDecl *>(td);
+    mtd->setInheritanceClauseChecked(valid);
+  } else {
+    auto *ed = declUnion.get<const ExtensionDecl *>();
+    auto *med = const_cast<ExtensionDecl *>(ed);
+    med->setInheritanceClauseChecked(valid);
+  }
 }
 
 static void installCodingKeysIfNecessary(NominalTypeDecl *NTD) {