[clang][deps] NFC: Respect working directory on construction

[jansvoboda11]

Summary

This patch provides FileManager with the CWD on construction in the worker, rather than later in the action.

Depends on D134976.

[jansvoboda11]

Always check input exists.

clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp

bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
 
     ScanInstance.getPreprocessorOpts().AllowPCHWithDifferentModulesCachePath =
         true;
 
     ScanInstance.getFrontendOpts().GenerateGlobalModuleIndex = false;
     ScanInstance.getFrontendOpts().UseGlobalModuleIndex = false;
     ScanInstance.getFrontendOpts().ModulesShareFileManager = false;
 
-    FileMgr->getFileSystemOpts().WorkingDir = std::string(WorkingDirectory);
     ScanInstance.setFileManager(FileMgr);
     ScanInstance.createSourceManager(*FileMgr);
 
     llvm::StringSet<> PrebuiltModulesInputFiles;
     // Store the list of prebuilt module files into header search options. This
     // will prevent the implicit build to create duplicate modules and will
     // force reuse of the existing prebuilt module files instead.
     if (!ScanInstance.getPreprocessorOpts().ImplicitPCHInclude.empty())
std::unique_ptr<driver::Driver> Driver = std::make_unique<driver::Driver>(
       Args[0], llvm::sys::getDefaultTargetTriple(), Diags,
       "clang LLVM compiler", &FM.getVirtualFileSystem());
   Driver->setTitle("clang_based_tool");
 
   std::vector<const char *> Argv;
   for (const std::string &Arg : Args)
     Argv.push_back(Arg.c_str());
 
-  // The "input file not found" diagnostics from the driver are useful.
-  // The driver is only aware of the VFS working directory, but some clients
-  // change this at the FileManager level instead.
-  // In this case the checks have false positives, so skip them.
-  if (!FM.getFileSystemOpts().WorkingDir.empty())
-    Driver->setCheckInputsExist(false);
   const std::unique_ptr<driver::Compilation> Compilation(
       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
   if (!Compilation)
     return false;
 
   for (const driver::Command &Job : Compilation->getJobs()) {
     if (!Callback(Job))
       return false;
   }
   return true;
 }
 
 bool DependencyScanningWorker::computeDependencies(
     StringRef WorkingDirectory, const std::vector<std::string> &CommandLine,
     DependencyConsumer &Consumer, DiagnosticConsumer &DC,
     llvm::Optional<StringRef> ModuleName) {
   // Reset what might have been modified in the previous worker invocation.
   RealFS->setCurrentWorkingDirectory(WorkingDirectory);
 
-  auto FileMgr =
-      llvm::makeIntrusiveRefCnt<FileManager>(FileSystemOptions(), RealFS);
+  FileSystemOptions FSOpts;
+  FSOpts.WorkingDir = WorkingDirectory.str();
+  auto FileMgr = llvm::makeIntrusiveRefCnt<FileManager>(FSOpts, RealFS);
 
   Optional<std::vector<std::string>> ModifiedCommandLine;
   if (ModuleName) {
     ModifiedCommandLine = CommandLine;
     InMemoryFS->addFile(*ModuleName, 0, llvm::MemoryBuffer::getMemBuffer(""));
     ModifiedCommandLine->emplace_back(*ModuleName);
   }