[Tooling] Produce diagnostics for missing input files.

Summary:
This was disabled way back in 2011, in the dark times before Driver was VFS-aware.

Also, make driver more VFS-aware :-)

This breaks one ClangTidy test (we improved the error message), will fix when
submitting.

Reviewers: ioeric

Subscribers: cfe-commits, alexfh

Differential Revision: https://reviews.llvm.org/D53958

llvm-svn: 346414

2 files changed, 1 insertions, 3 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 18fc4b7eabc..c784fec1366 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1972,7 +1972,7 @@ static bool DiagnoseInputExistence(const Driver &D, const DerivedArgList &Args,
     }
   }
 
-  if (llvm::sys::fs::exists(Twine(Path)))
+  if (D.getVFS().exists(Path))
     return true;
 
   if (D.IsCLMode()) {
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index eb9451d8b76..f143f7fe71f 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -303,8 +303,6 @@ bool ToolInvocation::run() {
 
   const std::unique_ptr<driver::Driver> Driver(
       newDriver(&Diagnostics, BinaryName, Files->getVirtualFileSystem()));
-  // Since the input might only be virtual, don't check whether it exists.
-  Driver->setCheckInputsExist(false);
   const std::unique_ptr<driver::Compilation> Compilation(
       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
   if (!Compilation)