Frontend: Always create a new FileManager in ASTUnit::CodeComplete

[dexonsmith]

Summary

The filesystem underneath it may have changed. This matches other
ASTUnit entry points like Reparse, and unblocks implementing
remapped files in a VFS layer underneath the FileManager in a future
patch.

[dexonsmith]

ping

clang/include/clang/Frontend/ASTUnit.h

public:
   /// FIXME: The Diag, LangOpts, SourceMgr, FileMgr, StoredDiagnostics, and
   /// OwnedBuffers parameters are all disgusting hacks. They will go away.
   void CodeComplete(StringRef File, unsigned Line, unsigned Column,
                     ArrayRef<RemappedFile> RemappedFiles, bool IncludeMacros,
                     bool IncludeCodePatterns, bool IncludeBriefComments,
                     CodeCompleteConsumer &Consumer,
                     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                     DiagnosticsEngine &Diag, LangOptions &LangOpts,
-                    SourceManager &SourceMgr, FileManager &FileMgr,
                     SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
                     SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers);
 
   /// Save this translation unit to a file with the given name.
   ///
   /// \returns true if there was a file error or false if the save was
   /// successful.
   bool Save(StringRef File);

clang/lib/Frontend/ASTUnit.cpp

 }
 
 void ASTUnit::CodeComplete(
     StringRef File, unsigned Line, unsigned Column,
     ArrayRef<RemappedFile> RemappedFiles, bool IncludeMacros,
     bool IncludeCodePatterns, bool IncludeBriefComments,
     CodeCompleteConsumer &Consumer,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-    DiagnosticsEngine &Diag, LangOptions &LangOpts, SourceManager &SourceMgr,
-    FileManager &FileMgr, SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
+    DiagnosticsEngine &Diag, LangOptions &LangOpts,
+    SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
     SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers) {
   if (!Invocation)
     return;
 
   SimpleTimer CompletionTimer(WantTiming);
   CompletionTimer.setOutput("Code completion @ " + File + ":" +
                             Twine(Line) + ":" + Twine(Column));
 
assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
          "Invocation must have exactly one source file!");
   assert(Clang->getFrontendOpts().Inputs[0].getKind().getFormat() ==
              InputKind::Source &&
          "FIXME: AST inputs not yet supported here!");
   assert(Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() !=
              Language::LLVM_IR &&
          "IR inputs not support here!");
 
-  // Use the source and file managers that we were given.
-  Clang->setFileManager(&FileMgr);
-  Clang->setSourceManager(&SourceMgr);
+  // Initialize file and source managers up front so that the caller can access
+  // them after.
+  Clang->createFileManager(FS);
+  FileMgr = &Clang->getFileManager();
+  Clang->createSourceManager(*FileMgr);
+  SourceMgr = &Clang->getSourceManager();
 
   // Remap files.
   PreprocessorOpts.clearRemappedFiles();
   PreprocessorOpts.RetainRemappedFileBuffers = true;
   for (const auto &RemappedFile : RemappedFiles) {
     PreprocessorOpts.addRemappedFile(RemappedFile.first, RemappedFile.second);
     OwnedBuffers.push_back(RemappedFile.second);
   }

clang/tools/libclang/CIndexCodeCompletion.cpp

 /// Used for debugging purposes only.
 static std::atomic<unsigned> CodeCompletionResultObjects;
 
 AllocatedCXCodeCompleteResults::AllocatedCXCodeCompleteResults(
     IntrusiveRefCntPtr<FileManager> FileMgr)
     : CXCodeCompleteResults(), DiagOpts(new DiagnosticOptions),
       Diag(new DiagnosticsEngine(
           IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs), &*DiagOpts)),
-      FileMgr(std::move(FileMgr)),
-      SourceMgr(new SourceManager(*Diag, *this->FileMgr)),
       CodeCompletionAllocator(
           std::make_shared<clang::GlobalCodeCompletionAllocator>()),
       Contexts(CXCompletionContext_Unknown),
       ContainerKind(CXCursor_InvalidCode), ContainerIsIncomplete(1) {
   if (getenv("LIBCLANG_OBJTRACKING"))
     fprintf(stderr, "+++ %u completion results\n",
             ++CodeCompletionResultObjects);
 }
for (const auto &Arg : TU->Arguments)
     CArgs.push_back(Arg.c_str());
   std::string CompletionInvocation =
       llvm::formatv("-code-completion-at={0}:{1}:{2}", complete_filename,
                     complete_line, complete_column)
           .str();
   LibclangInvocationReporter InvocationReporter(
       *CXXIdx, LibclangInvocationReporter::OperationKind::CompletionOperation,
       TU->ParsingOptions, CArgs, CompletionInvocation, unsaved_files);
-  AST->CodeComplete(complete_filename, complete_line, complete_column,
-                    RemappedFiles, (options & CXCodeComplete_IncludeMacros),
-                    (options & CXCodeComplete_IncludeCodePatterns),
-                    IncludeBriefComments, Capture,
-                    CXXIdx->getPCHContainerOperations(), *Results->Diag,
-                    Results->LangOpts, *Results->SourceMgr, *Results->FileMgr,
-                    Results->Diagnostics, Results->TemporaryBuffers);
+  AST->CodeComplete(
+      complete_filename, complete_line, complete_column, RemappedFiles,
+      (options & CXCodeComplete_IncludeMacros),
+      (options & CXCodeComplete_IncludeCodePatterns), IncludeBriefComments,
+      Capture, CXXIdx->getPCHContainerOperations(), *Results->Diag,
+      Results->LangOpts, Results->Diagnostics, Results->TemporaryBuffers);
 
+  Results->FileMgr = &AST->getFileManager();
+  Results->SourceMgr = &AST->getSourceManager();
   Results->DiagnosticsWrappers.resize(Results->Diagnostics.size());
 
   // Keep a reference to the allocator used for cached global completions, so
   // that we can be sure that the memory used by our code completion strings
   // doesn't get freed due to subsequent reparses (while the code completion
   // results are still active).
   Results->CachedCompletionAllocator = AST->getCachedCompletionAllocator();