don't crawl exported imports more than once

Author: QuietMisdreavus

include/swift/AST/SourceFile.h

@@ -288,6 +288,10 @@ class SourceFile final : public FileUnit {
 
   ~SourceFile();
 
+  bool hasImports() const {
+    return Imports.hasValue();
+  }
+
   /// Retrieve an immutable view of the source file's imports.
   ArrayRef<AttributedImport<ImportedModule>> getImports() const {
     return *Imports;
@@ -393,8 +397,6 @@ class SourceFile final : public FileUnit {
 public:
   virtual void getTopLevelDecls(SmallVectorImpl<Decl*> &results) const override;
 
-  virtual void getDisplayDecls(SmallVectorImpl<Decl*> &results) const override;
-
   virtual void
   getOperatorDecls(SmallVectorImpl<OperatorDecl *> &results) const override;
 

lib/AST/Module.cpp

@@ -780,6 +780,22 @@ void SourceFile::lookupObjCMethods(
   results.append(known->second.begin(), known->second.end());
 }
 
+static void collectParsedExportedImports(const ModuleDecl *M, SmallPtrSetImpl<ModuleDecl *> &Imports) {
+  for (const FileUnit *file : M->getFiles()) {
+    if (const SourceFile *source = dyn_cast<SourceFile>(file)) {
+      if (source->hasImports()) {
+        for (auto import : source->getImports()) {
+          if (import.options.contains(ImportFlags::Exported)) {
+            if (!Imports.contains(import.module.importedModule)) {
+              Imports.insert(import.module.importedModule);
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
 void ModuleDecl::getLocalTypeDecls(SmallVectorImpl<TypeDecl*> &Results) const {
   FORWARD(getLocalTypeDecls, (Results));
 }
@@ -822,17 +838,6 @@ void SourceFile::getTopLevelDecls(SmallVectorImpl<Decl*> &Results) const {
   Results.append(decls.begin(), decls.end());
 }
 
-void SourceFile::getDisplayDecls(SmallVectorImpl<Decl*> &Results) const {
-  if (Imports.hasValue()) {
-    for (auto import : *Imports) {
-      if (import.options.contains(ImportFlags::Exported)) {
-        import.module.importedModule->getDisplayDecls(Results);
-      }
-    }
-  }
-  getTopLevelDecls(Results);
-}
-
 void ModuleDecl::getOperatorDecls(
     SmallVectorImpl<OperatorDecl *> &results) const {
   // For a parsed module, we can check the source cache on the module rather
@@ -937,8 +942,23 @@ SourceFile::getExternalRawLocsForDecl(const Decl *D) const {
 }
 
 void ModuleDecl::getDisplayDecls(SmallVectorImpl<Decl*> &Results) const {
+  if (isParsedModule(this)) {
+    SmallPtrSet<ModuleDecl *, 4> Modules;
+    collectParsedExportedImports(this, Modules);
+    for (const ModuleDecl *import : Modules) {
+      import->getDisplayDecls(Results);
+    }
+  }
   // FIXME: Should this do extra access control filtering?
   FORWARD(getDisplayDecls, (Results));
+
+#ifndef NDEBUG
+  llvm::DenseSet<Decl *> visited;
+  for (auto *D : Results) {
+    auto inserted = visited.insert(D).second;
+    assert(inserted && "there should be no duplicate decls");
+  }
+#endif
 }
 
 ProtocolConformanceRef

test/SymbolGraph/ClangImporter/EmitWhileBuilding.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: cp -r %S/Inputs/EmitWhileBuilding/EmitWhileBuilding.framework %t
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -emit-module-path %t/EmitWhileBuilding.framework/Modules/EmitWhileBuilding.swiftmodule/%target-swiftmodule-name -import-underlying-module -F %t -module-name EmitWhileBuilding -disable-objc-attr-requires-foundation-module %s -emit-symbol-graph -emit-symbol-graph-dir %t
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -emit-module-path %t/EmitWhileBuilding.framework/Modules/EmitWhileBuilding.swiftmodule/%target-swiftmodule-name -import-underlying-module -F %t -module-name EmitWhileBuilding -disable-objc-attr-requires-foundation-module %s %S/Inputs/EmitWhileBuilding/Extra.swift -emit-symbol-graph -emit-symbol-graph-dir %t
 // RUN: %{python} -m json.tool %t/EmitWhileBuilding.symbols.json %t/EmitWhileBuilding.formatted.symbols.json
 // RUN: %FileCheck %s --input-file %t/EmitWhileBuilding.formatted.symbols.json
 // RUN: %FileCheck %s --input-file %t/EmitWhileBuilding.formatted.symbols.json --check-prefix HEADER

test/SymbolGraph/ClangImporter/Inputs/EmitWhileBuilding/Extra.swift

@@ -0,0 +1 @@
+public struct SomeStruct {}