[Cleanup] Eliminate DerivedFileUnit.

The only client of DerivedFileUnit was synthesized global '=='
operators for Equatable conformances, which has since been removed.

Author: DougGregor

include/swift/AST/Module.h

@@ -53,7 +53,6 @@ namespace swift {
   class ExtensionDecl;
   class DebuggerClient;
   class DeclName;
-  class DerivedFileUnit;
   class FileUnit;
   class FuncDecl;
   class InfixOperatorDecl;
@@ -238,8 +237,6 @@ class ModuleDecl : public TypeDecl, public DeclContext {
   /// dealing with.
   FileUnit &getMainFile(FileUnitKind expectedKind) const;
 
-  DerivedFileUnit &getDerivedFileUnit() const;
-
   DebuggerClient *getDebugClient() const { return DebugClient; }
   void setDebugClient(DebuggerClient *R) {
     assert(!DebugClient && "Debugger client already set");
@@ -750,47 +747,6 @@ class FileUnit : public DeclContext {
                      unsigned Alignment = alignof(FileUnit));
 };
 
-/// A container for a module-level definition derived as part of an implicit
-/// protocol conformance.
-class DerivedFileUnit final : public FileUnit {
-  TinyPtrVector<FuncDecl *> DerivedDecls;
-
-public:
-  DerivedFileUnit(ModuleDecl &M);
-  ~DerivedFileUnit() = default;
-
-  void addDerivedDecl(FuncDecl *FD) {
-    DerivedDecls.push_back(FD);
-  }
-
-  void lookupValue(ModuleDecl::AccessPathTy accessPath, DeclName name,
-                   NLKind lookupKind,
-                   SmallVectorImpl<ValueDecl*> &result) const override;
-  
-  void lookupVisibleDecls(ModuleDecl::AccessPathTy accessPath,
-                          VisibleDeclConsumer &consumer,
-                          NLKind lookupKind) const override;
-  
-  void getTopLevelDecls(SmallVectorImpl<Decl*> &results) const override;
-
-  void lookupObjCMethods(
-         ObjCSelector selector,
-         SmallVectorImpl<AbstractFunctionDecl *> &results) const override;
-
-  Identifier
-  getDiscriminatorForPrivateValue(const ValueDecl *D) const override {
-    llvm_unreachable("no private decls in the derived file unit");
-  }
-
-  static bool classof(const FileUnit *file) {
-    return file->getKind() == FileUnitKind::Derived;
-  }
-  static bool classof(const DeclContext *DC) {
-    return isa<FileUnit>(DC) && classof(cast<FileUnit>(DC));
-  }
-};
-
-
 /// A file containing Swift source code.
 ///
 /// This is a .swift or .sil file (or a virtual file, such as the contents of

lib/AST/ASTContext.cpp

@@ -1229,13 +1229,7 @@ void ASTContext::verifyAllLoadedModules() const {
 
   for (auto &topLevelModulePair : LoadedModules) {
     Module *M = topLevelModulePair.second;
-    bool hasAnyFileUnits = std::any_of(M->getFiles().begin(),
-                                       M->getFiles().end(),
-                                       [](const FileUnit *file) {
-      return !isa<DerivedFileUnit>(file);
-    });
-    if (!hasAnyFileUnits)
-      assert(M->failedToLoad());
+    assert(!M->getFiles().empty() || M->failedToLoad());
   }
 #endif
 }

lib/AST/Module.cpp

@@ -347,35 +347,12 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx)
 }
 
 void Module::addFile(FileUnit &newFile) {
-  assert(!isa<DerivedFileUnit>(newFile) &&
-         "DerivedFileUnits are added automatically");
-
   // Require Main and REPL files to be the first file added.
   assert(Files.empty() ||
          !isa<SourceFile>(newFile) ||
          cast<SourceFile>(newFile).Kind == SourceFileKind::Library ||
          cast<SourceFile>(newFile).Kind == SourceFileKind::SIL);
   Files.push_back(&newFile);
-
-  switch (newFile.getKind()) {
-  case FileUnitKind::Source:
-  case FileUnitKind::ClangModule: {
-    for (auto File : Files) {
-      if (isa<DerivedFileUnit>(File))
-        return;
-    }
-    auto DFU = new (getASTContext()) DerivedFileUnit(*this);
-    Files.push_back(DFU);
-    break;
-  }
-
-  case FileUnitKind::Builtin:
-  case FileUnitKind::SerializedAST:
-    break;
-
-  case FileUnitKind::Derived:
-    llvm_unreachable("DerivedFileUnits are added automatically");
-  }
 }
 
 void Module::removeFile(FileUnit &existingFile) {
@@ -390,15 +367,6 @@ void Module::removeFile(FileUnit &existingFile) {
   Files.erase(I.base());
 }
 
-DerivedFileUnit &Module::getDerivedFileUnit() const {
-  for (auto File : Files) {
-    if (auto DFU = dyn_cast<DerivedFileUnit>(File))
-      return *DFU;
-  }
-  llvm_unreachable("the client should not be calling this function if "
-                   "there is no DerivedFileUnit");
-}
-
 VarDecl *Module::getDSOHandle() {
   if (DSOHandle)
     return DSOHandle;
@@ -540,58 +508,6 @@ void BuiltinUnit::lookupObjCMethods(
   // No @objc methods in the Builtin module.
 }
 
-DerivedFileUnit::DerivedFileUnit(Module &M)
-    : FileUnit(FileUnitKind::Derived, M) {
-  M.getASTContext().addDestructorCleanup(*this);
-}
-
-void DerivedFileUnit::lookupValue(Module::AccessPathTy accessPath,
-                                  DeclName name,
-                                  NLKind lookupKind,
-                                  SmallVectorImpl<ValueDecl*> &result) const {
-  // If this import is specific to some named type or decl ("import Swift.int")
-  // then filter out any lookups that don't match.
-  if (!Module::matchesAccessPath(accessPath, name))
-    return;
-  
-  for (auto D : DerivedDecls) {
-    if (D->getFullName().matchesRef(name))
-      result.push_back(D);
-  }
-}
-
-void DerivedFileUnit::lookupVisibleDecls(Module::AccessPathTy accessPath,
-                                         VisibleDeclConsumer &consumer,
-                                         NLKind lookupKind) const {
-  assert(accessPath.size() <= 1 && "can only refer to top-level decls");
-  
-  Identifier Id;
-  if (!accessPath.empty()) {
-    Id = accessPath.front().first;
-  }
-
-  for (auto D : DerivedDecls) {
-    if (Id.empty() || D->getName() == Id)
-      consumer.foundDecl(D, DeclVisibilityKind::VisibleAtTopLevel);
-  }
-}
-
-void DerivedFileUnit::lookupObjCMethods(
-       ObjCSelector selector,
-       SmallVectorImpl<AbstractFunctionDecl *> &results) const {
-  for (auto D : DerivedDecls) {
-    if (auto func = dyn_cast<AbstractFunctionDecl>(D)) {
-      if (func->isObjC() && func->getObjCSelector() == selector)
-        results.push_back(func);
-    }
-  }
-}
-
-void DerivedFileUnit::getTopLevelDecls(SmallVectorImpl<swift::Decl *> &results)
-const {
-  results.append(DerivedDecls.begin(), DerivedDecls.end());
-}
-
 void SourceFile::lookupValue(Module::AccessPathTy accessPath, DeclName name,
                              NLKind lookupKind,
                              SmallVectorImpl<ValueDecl*> &result) const {
@@ -1203,8 +1119,6 @@ StringRef Module::getModuleFilename() const {
       Result = LF->getFilename();
       continue;
     }
-    if (isa<DerivedFileUnit>(F))
-      continue;
     return StringRef();
   }
   return Result;

lib/Sema/CodeSynthesis.cpp

@@ -37,9 +37,6 @@ static void addMemberToContextIfNeeded(Decl *D, DeclContext *DC,
     ntd->addMember(D, Hint);
   } else if (auto *ed = dyn_cast<ExtensionDecl>(DC)) {
     ed->addMember(D, Hint);
-  } else if (isa<SourceFile>(DC)) {
-    auto *mod = DC->getParentModule();
-    mod->getDerivedFileUnit().addDerivedDecl(cast<FuncDecl>(D));
   } else {
     assert((isa<AbstractFunctionDecl>(DC) || isa<FileUnit>(DC)) &&
            "Unknown declcontext");

test/SILGen/property_behavior.swift

@@ -9,7 +9,7 @@ extension behavior {
   }
 }
 
-// TODO: global accessor doesn't get walked because it's in DerivedFileUnit
+// TODO: global accessor doesn't get walked??
 var global: Int __behavior behavior
 
 struct S1<T> {

unittests/AST/OverrideTests.cpp

@@ -52,36 +52,34 @@ class TestContext : public TestContextBase {
   SourceFile *FileForLookups;
 
   void declareOptionalType(Identifier name) {
-    auto wrapped = new (Ctx) GenericTypeParamDecl(File,
+    auto wrapped = new (Ctx) GenericTypeParamDecl(FileForLookups,
                                                   Ctx.getIdentifier("Wrapped"),
                                                   SourceLoc(), /*depth*/0,
                                                   /*index*/0);
     auto params = GenericParamList::create(Ctx, SourceLoc(), wrapped,
                                            SourceLoc());
     auto decl = new (Ctx) EnumDecl(SourceLoc(), name, SourceLoc(),
-                                   /*inherited*/{}, params, File);
+                                   /*inherited*/{}, params, FileForLookups);
     wrapped->setDeclContext(decl);
     FileForLookups->Decls.push_back(decl);
   }
 
 public:
   ASTContext Ctx;
-  DerivedFileUnit *File;
 
   TestContext(ShouldDeclareOptionalTypes optionals = DoNotDeclareOptionalTypes)
       : Ctx(LangOpts, SearchPathOpts, SourceMgr, Diags) {
     auto stdlibID = Ctx.getIdentifier(STDLIB_NAME);
     auto *module = ModuleDecl::create(stdlibID, Ctx);
     Ctx.LoadedModules[stdlibID] = module;
-    File = new (Ctx) DerivedFileUnit(*module);
 
-    if (optionals == DeclareOptionalTypes) {
-      using ImplicitModuleImportKind = SourceFile::ImplicitModuleImportKind;
-      FileForLookups = new (Ctx) SourceFile(*module, SourceFileKind::Library,
-                                            /*buffer*/None,
-                                            ImplicitModuleImportKind::None);
-      module->addFile(*FileForLookups);
+    using ImplicitModuleImportKind = SourceFile::ImplicitModuleImportKind;
+    FileForLookups = new (Ctx) SourceFile(*module, SourceFileKind::Library,
+                                          /*buffer*/None,
+                                          ImplicitModuleImportKind::None);
+    module->addFile(*FileForLookups);
 
+    if (optionals == DeclareOptionalTypes) {
       declareOptionalType(Ctx.getIdentifier("Optional"));
       declareOptionalType(Ctx.getIdentifier("ImplicitlyUnwrappedOptional"));
     }
@@ -92,7 +90,7 @@ class TestContext : public TestContextBase {
                        GenericParamList *genericParams = nullptr) {
     auto result = new (Ctx) Nominal(SourceLoc(), Ctx.getIdentifier(name),
                                     SourceLoc(), /*inherited*/{},
-                                    genericParams, File);
+                                    genericParams, FileForLookups);
     result->setAccessibility(Accessibility::Internal);
     return result;
   }