[Tooling] Remove unused function setRestoreWorkingDir

The last use was removed by:

  commit 146ec74
  Author: Jan Svoboda <jan_svoboda@apple.com>
  Date:   Fri Sep 10 10:24:16 2021 +0200

Once I remove the function, RestoreCWD is always true, so this patch
removes the variable and propagates the constant.

Differential Revision: https://reviews.llvm.org/D151786

clang/include/clang/Tooling/Tooling.h

@@ -361,11 +361,6 @@ class ClangTool {
   /// append them to ASTs.
   int buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs);
 
-  /// Sets whether working directory should be restored after calling run(). By
-  /// default, working directory is restored. However, it could be useful to
-  /// turn this off when running on multiple threads to avoid the raciness.
-  void setRestoreWorkingDir(bool RestoreCWD);
-
   /// Sets whether an error message should be printed out if an action fails. By
   /// default, if an action fails, a message is printed out to stderr.
   void setPrintErrorMessage(bool PrintErrorMessage);
@@ -395,7 +390,6 @@ class ClangTool {
 
   DiagnosticConsumer *DiagConsumer = nullptr;
 
-  bool RestoreCWD = true;
   bool PrintErrorMessage = true;
 };
 

clang/lib/Tooling/Tooling.cpp

@@ -542,13 +542,11 @@ int ClangTool::run(ToolAction *Action) {
 
   // Remember the working directory in case we need to restore it.
   std::string InitialWorkingDir;
-  if (RestoreCWD) {
-    if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
-      InitialWorkingDir = std::move(*CWD);
-    } else {
-      llvm::errs() << "Could not get working directory: "
-                   << CWD.getError().message() << "\n";
-    }
+  if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
+    InitialWorkingDir = std::move(*CWD);
+  } else {
+    llvm::errs() << "Could not get working directory: "
+                 << CWD.getError().message() << "\n";
   }
 
   for (llvm::StringRef File : AbsolutePaths) {
@@ -662,10 +660,6 @@ int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
   return run(&Action);
 }
 
-void ClangTool::setRestoreWorkingDir(bool RestoreCWD) {
-  this->RestoreCWD = RestoreCWD;
-}
-
 void ClangTool::setPrintErrorMessage(bool PrintErrorMessage) {
   this->PrintErrorMessage = PrintErrorMessage;
 }