[Tooling] Restore working dir in ClangTool.

Summary:
And add an option to disable this behavior. The option is only used in
AllTUsExecutor to avoid races when running concurrently on multiple
threads.

This fixes PR38869 introduced by r340937.

Reviewers: ioeric, steveire

Reviewed By: ioeric

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D51864

llvm-svn: 341910

1 files changed, 13 insertions, 1 deletions

diff --git a/clang/lib/Tooling/AllTUsExecution.cpp b/clang/lib/Tooling/AllTUsExecution.cpp
index b761556ee76..a7af541cc5d 100644
--- a/clang/lib/Tooling/AllTUsExecution.cpp
+++ b/clang/lib/Tooling/AllTUsExecution.cpp
@@ -104,7 +104,12 @@ llvm::Error AllTUsToolExecutor::execute(
   {
     llvm::ThreadPool Pool(ThreadCount == 0 ? llvm::hardware_concurrency()
                                            : ThreadCount);
-
+    llvm::SmallString<128> InitialWorkingDir;
+    if (auto EC = llvm::sys::fs::current_path(InitialWorkingDir)) {
+      InitialWorkingDir = "";
+      llvm::errs() << "Error while getting current working directory: "
+                   << EC.message() << "\n";
+    }
     for (std::string File : Files) {
       Pool.async(
           [&](std::string Path) {
@@ -116,12 +121,19 @@ llvm::Error AllTUsToolExecutor::execute(
             for (const auto &FileAndContent : OverlayFiles)
               Tool.mapVirtualFile(FileAndContent.first(),
                                   FileAndContent.second);
+            // Do not restore working dir from multiple threads to avoid races.
+            Tool.setRestoreWorkingDir(false);
             if (Tool.run(Action.first.get()))
               AppendError(llvm::Twine("Failed to run action on ") + Path +
                           "\n");
           },
           File);
     }
+    if (!InitialWorkingDir.empty()) {
+      if (auto EC = llvm::sys::fs::set_current_path(InitialWorkingDir))
+        llvm::errs() << "Error while restoring working directory: "
+                     << EC.message() << "\n";
+    }
   }
 
   if (!ErrorMsg.empty())