[clang][include-tree] Fix spurious dependencies

Author: jansvoboda11

clang/include/clang/Basic/Module.h

@@ -350,6 +350,10 @@ class alignas(8) Module {
   LLVM_PREFERRED_TYPE(bool)
   unsigned IsInferred : 1;
 
+  /// Whether this is an inferred submodule that's missing from the umbrella
+  /// header.
+  unsigned IsInferredMissingFromUmbrellaHeader : 1;
+
   /// Whether we should infer submodules for this module based on
   /// the headers.
   ///

clang/lib/Basic/Module.cpp

@@ -42,6 +42,7 @@ Module::Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent,
       HasIncompatibleModuleFile(false), IsAvailable(true),
       IsFromModuleFile(false), IsFramework(IsFramework), IsExplicit(IsExplicit),
       IsSystem(false), IsExternC(false), IsInferred(false),
+      IsInferredMissingFromUmbrellaHeader(false),
       InferSubmodules(false), InferExplicitSubmodules(false),
       InferExportWildcard(false), ConfigMacrosExhaustive(false),
       NoUndeclaredIncludes(false), ModuleMapIsPrivate(false),

clang/lib/Frontend/CompilerInstance.cpp

@@ -2227,6 +2227,8 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
         << Module->getFullModuleName()
         << SourceRange(Path.front().second, Path.back().second);
 
+      Module->IsInferredMissingFromUmbrellaHeader = true;
+
       return ModuleLoadResult(Module, ModuleLoadResult::MissingExpected);
     }
 

clang/lib/Tooling/DependencyScanning/IncludeTreeActionController.cpp

@@ -204,12 +204,7 @@ struct IncludeTreePPCallbacks : public PPCallbacks {
                           bool ModuleImported,
                           SrcMgr::CharacteristicKind FileType) override {
     // File includes are handled by LexedFileChanged.
-    if (!SuggestedModule)
-      return;
-
-    // Modules that will not be imported and were not loaded from an AST file
-    // (e.g. the module being implemented) are also handled by LexedFileChanged.
-    if (!ModuleImported && !SuggestedModule->getASTFile())
+    if (!ModuleImported)
       return;
 
     // Calculate EndLoc for the directive
@@ -462,20 +457,25 @@ void IncludeTreeBuilder::exitedInclude(Preprocessor &PP, FileID IncludedBy,
   SourceManager &SM = PP.getSourceManager();
   std::pair<FileID, unsigned> LocInfo = SM.getDecomposedExpansionLoc(ExitLoc);
 
-  // If the file includes already has a node for the current source location, it
-  // must be an import that turned out to be spurious.
-  auto &CurIncludes = IncludeStack.back().Includes;
-  if (!CurIncludes.empty() && CurIncludes.back().Offset == LocInfo.second) {
-    assert(!IncludeTree->isSubmodule());
-    auto Import = CurIncludes.pop_back_val();
-    assert(Import.Kind == cas::IncludeTree::NodeKind::ModuleImport);
-    auto SpuriousImport = cas::IncludeTree::SpuriousImport::create(
-        DB, Import.Ref, IncludeTree->getRef());
-    if (!SpuriousImport)
+  if (auto FE = PP.getSourceManager().getFileEntryRefForID(Include)) {
+    ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
+    Module *M = ModMap.findModuleForHeader(*FE).getModule();
+    if (M && M->IsInferredMissingFromUmbrellaHeader) {
+      assert(!IncludeTree->isSubmodule() &&
+             "Include of header missing from umbrella header is modular");
+
+      moduleImport(PP, M, ExitLoc);
+      auto Import = IncludeStack.back().Includes.pop_back_val();
+
+      auto SpuriousImport = check(cas::IncludeTree::SpuriousImport::create(
+          DB, Import.Ref, IncludeTree->getRef()));
+      if (!SpuriousImport)
+        return;
+      IncludeStack.back().Includes.push_back(
+          {SpuriousImport->getRef(), LocInfo.second,
+           cas::IncludeTree::NodeKind::SpuriousImport});
       return;
-    CurIncludes.push_back({SpuriousImport->getRef(), LocInfo.second,
-                           cas::IncludeTree::NodeKind::SpuriousImport});
-    return;
+    }
   }
 
   IncludeStack.back().Includes.push_back({IncludeTree->getRef(), LocInfo.second,