[clang] [clang][DependencyScanning] Track dependencies from prebuilt modules to determine IsInStableDir (PR #132237)

[Jan Svoboda via cfe-commits]

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@@ -90,63 +90,132 @@ static bool checkHeaderSearchPaths(const HeaderSearchOptions &HSOpts,
 
 using PrebuiltModuleFilesT = decltype(HeaderSearchOptions::PrebuiltModuleFiles);
 
-/// A listener that collects the imported modules and optionally the input
-/// files.
+/// A listener that collects the imported modules and the input
+/// files. While visiting, collect vfsoverlays and file inputs that determine
+/// whether prebuilt modules fully resolve in stable directories.
 class PrebuiltModuleListener : public ASTReaderListener {
 public:
   PrebuiltModuleListener(PrebuiltModuleFilesT &PrebuiltModuleFiles,
                          llvm::SmallVector<std::string> &NewModuleFiles,
-                         PrebuiltModuleVFSMapT &PrebuiltModuleVFSMap,
+                         PrebuiltModulesAttrsMap &PrebuiltModulesASTMap,
                          const HeaderSearchOptions &HSOpts,
-                         const LangOptions &LangOpts, DiagnosticsEngine &Diags)
+                         const LangOptions &LangOpts, DiagnosticsEngine &Diags,
+                         const llvm::SmallVector<StringRef> &StableDirs)
       : PrebuiltModuleFiles(PrebuiltModuleFiles),
         NewModuleFiles(NewModuleFiles),
-        PrebuiltModuleVFSMap(PrebuiltModuleVFSMap), ExistingHSOpts(HSOpts),
-        ExistingLangOpts(LangOpts), Diags(Diags) {}
+        PrebuiltModulesASTMap(PrebuiltModulesASTMap), ExistingHSOpts(HSOpts),
+        ExistingLangOpts(LangOpts), Diags(Diags), StableDirs(StableDirs) {}
 
   bool needsImportVisitation() const override { return true; }
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override { return true; }
 
+  /// Accumulate the modules are transitively depended on by the initial
+  /// prebuilt module.
   void visitImport(StringRef ModuleName, StringRef Filename) override {
     if (PrebuiltModuleFiles.insert({ModuleName.str(), Filename.str()}).second)
       NewModuleFiles.push_back(Filename.str());
+
+    if (PrebuiltModulesASTMap.try_emplace(Filename).second)
+      PrebuiltModulesASTMap[Filename].setInStableDir(!StableDirs.empty());
+
+    if (auto It = PrebuiltModulesASTMap.find(CurrentFile);
+        It != PrebuiltModulesASTMap.end() && CurrentFile != Filename)
+      PrebuiltModulesASTMap[Filename].addDependent(It->getKey());
+  }
+
+  /// For each input file discovered, check whether it's external path is in a
+  /// stable directory. Traversal is stopped if the current module is not
+  /// considered stable.
+  bool visitInputFile(StringRef FilenameAsRequested, StringRef ExternalFilename,
+                      bool isSystem, bool isOverridden,
+                      bool isExplicitModule) override {
+    if (StableDirs.empty())
+      return false;
+    if (!PrebuiltModulesASTMap.contains(CurrentFile) ||
+        !PrebuiltModulesASTMap[CurrentFile].isInStableDir())
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jansvoboda11 wrote:

Nit: Double lookup.

https://github.com/llvm/llvm-project/pull/132237