[clang-tools-extra] [clangd] [Modules] Support Reusable Modules Builder (PR #106683)

[Chuanqi Xu via cfe-commits]

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@@ -228,54 +223,30 @@ class StandalonePrerequisiteModules : public PrerequisiteModules {
     return BuiltModuleNames.contains(ModuleName);
   }
 
-  void addModuleFile(llvm::StringRef ModuleName,
-                     llvm::StringRef ModuleFilePath) {
-    RequiredModules.emplace_back(ModuleName, ModuleFilePath);
-    BuiltModuleNames.insert(ModuleName);
+  void addModuleFile(std::shared_ptr<ModuleFile> BMI) {
+    BuiltModuleNames.insert(BMI->ModuleName);
+    RequiredModules.emplace_back(std::move(BMI));
   }
 
 private:
-  llvm::SmallVector<ModuleFile, 8> RequiredModules;
+  mutable llvm::SmallVector<std::shared_ptr<ModuleFile>, 8> RequiredModules;
   // A helper class to speedup the query if a module is built.
   llvm::StringSet<> BuiltModuleNames;
 };
 
-// Build a module file for module with `ModuleName`. The information of built
-// module file are stored in \param BuiltModuleFiles.
-llvm::Error buildModuleFile(llvm::StringRef ModuleName,
-                            const GlobalCompilationDatabase &CDB,
-                            const ThreadsafeFS &TFS, ProjectModules &MDB,
-                            PathRef ModuleFilesPrefix,
-                            StandalonePrerequisiteModules &BuiltModuleFiles) {
-  if (BuiltModuleFiles.isModuleUnitBuilt(ModuleName))
-    return llvm::Error::success();
-
-  PathRef ModuleUnitFileName = MDB.getSourceForModuleName(ModuleName);
-  // It is possible that we're meeting third party modules (modules whose
-  // source are not in the project. e.g, the std module may be a third-party
-  // module for most projects) or something wrong with the implementation of
-  // ProjectModules.
-  // FIXME: How should we treat third party modules here? If we want to ignore
-  // third party modules, we should return true instead of false here.
-  // Currently we simply bail out.
-  if (ModuleUnitFileName.empty())
-    return llvm::createStringError("Failed to get the primary source");
-
+/// Build a module file for module with `ModuleName`. The information of built
+/// module file are stored in \param BuiltModuleFiles.
+llvm::Expected<ModuleFile>
+buildModuleFile(llvm::StringRef ModuleName, PathRef ModuleUnitFileName,
+                const GlobalCompilationDatabase &CDB, const ThreadsafeFS &TFS,
+                PathRef ModuleFilesPrefix,
+                const ReusablePrerequisiteModules &BuiltModuleFiles) {
   // Try cheap operation earlier to boil-out cheaply if there are problems.
   auto Cmd = CDB.getCompileCommand(ModuleUnitFileName);
   if (!Cmd)
     return llvm::createStringError(
         llvm::formatv("No compile command for {0}", ModuleUnitFileName));
 
-  for (auto &RequiredModuleName : MDB.getRequiredModules(ModuleUnitFileName)) {
----------------
ChuanqiXu9 wrote:

See the following comment.

https://github.com/llvm/llvm-project/pull/106683