Resubmit "[clangd] The new threading implementation"

Initially submitted as r324356 and reverted in r324386.

This change additionally contains a fix to crashes of the buildbots.
The source of the crash was undefined behaviour caused by
std::future<> whose std::promise<> was destroyed without calling
set_value().

llvm-svn: 324575

1 files changed, 14 insertions, 11 deletions

diff --git a/clang-tools-extra/clangd/TUScheduler.h b/clang-tools-extra/clangd/TUScheduler.h
index c7df8c4dba1..c984b711209 100644
--- a/clang-tools-extra/clangd/TUScheduler.h
+++ b/clang-tools-extra/clangd/TUScheduler.h
@@ -11,9 +11,9 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_TUSCHEDULER_H
 
 #include "ClangdUnit.h"
-#include "ClangdUnitStore.h"
 #include "Function.h"
 #include "Threading.h"
+#include "llvm/ADT/StringMap.h"
 
 namespace clang {
 namespace clangd {
@@ -42,6 +42,7 @@ class TUScheduler {
 public:
   TUScheduler(unsigned AsyncThreadsCount, bool StorePreamblesInMemory,
               ASTParsedCallback ASTCallback);
+  ~TUScheduler();
 
   /// Returns estimated memory usage for each of the currently open files.
   /// The order of results is unspecified.
@@ -55,12 +56,8 @@ public:
                   OnUpdated);
 
   /// Remove \p File from the list of tracked files and schedule removal of its
-  /// resources. \p Action will be called when resources are freed.
-  /// If an error occurs during processing, it is forwarded to the \p Action
-  /// callback.
-  /// FIXME(ibiryukov): the callback passed to this function is not used, we
-  /// should remove it.
-  void remove(PathRef File, UniqueFunction<void(llvm::Error)> Action);
+  /// resources.
+  void remove(PathRef File);
 
   /// Schedule an async read of the AST. \p Action will be called when AST is
   /// ready. The AST passed to \p Action refers to the version of \p File
@@ -81,11 +78,17 @@ public:
       UniqueFunction<void(llvm::Expected<InputsAndPreamble>)> Action);
 
 private:
-  const ParseInputs &getInputs(PathRef File);
+  /// This class stores per-file data in the Files map.
+  struct FileData;
 
-  llvm::StringMap<ParseInputs> CachedInputs;
-  CppFileCollection Files;
-  ThreadPool Threads;
+  const bool StorePreamblesInMemory;
+  const std::shared_ptr<PCHContainerOperations> PCHOps;
+  const ASTParsedCallback ASTCallback;
+  Semaphore Barrier;
+  llvm::StringMap<std::unique_ptr<FileData>> Files;
+  // None when running tasks synchronously and non-None when running tasks
+  // asynchronously.
+  llvm::Optional<AsyncTaskRunner> Tasks;
 };
 } // namespace clangd
 } // namespace clang