Revert "[NFC] Explicitly pass a VFS when creating DiagnosticsEngine (#115852)"

Reverted for causing:
https://github.com/llvm/llvm-project/issues/117145

This reverts commit bdd10d9d249bd1c2a45e3de56a5accd97e953458.

8 files changed, 38 insertions, 48 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index fbfc305..ecc6782 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -332,20 +332,23 @@ static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
   }
 }
 
-void CompilerInstance::createDiagnostics(llvm::vfs::FileSystem &VFS,
-                                         DiagnosticConsumer *Client,
+void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
                                          bool ShouldOwnClient) {
-  Diagnostics = createDiagnostics(VFS, &getDiagnosticOpts(), Client,
-                                  ShouldOwnClient, &getCodeGenOpts());
+  Diagnostics = createDiagnostics(
+      &getDiagnosticOpts(), Client, ShouldOwnClient, &getCodeGenOpts(),
+      FileMgr ? FileMgr->getVirtualFileSystemPtr() : nullptr);
 }
 
 IntrusiveRefCntPtr<DiagnosticsEngine> CompilerInstance::createDiagnostics(
-    llvm::vfs::FileSystem &VFS, DiagnosticOptions *Opts,
-    DiagnosticConsumer *Client, bool ShouldOwnClient,
-    const CodeGenOptions *CodeGenOpts) {
+    DiagnosticOptions *Opts, DiagnosticConsumer *Client, bool ShouldOwnClient,
+    const CodeGenOptions *CodeGenOpts,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
-  IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
-      new DiagnosticsEngine(DiagID, Opts));
+  IntrusiveRefCntPtr<DiagnosticsEngine>
+      Diags(new DiagnosticsEngine(DiagID, Opts));
+
+  if (!VFS)
+    VFS = llvm::vfs::getRealFileSystem();
 
   // Create the diagnostic client for reporting errors or for
   // implementing -verify.
@@ -369,7 +372,7 @@ IntrusiveRefCntPtr<DiagnosticsEngine> CompilerInstance::createDiagnostics(
                                Opts->DiagnosticSerializationFile);
 
   // Configure our handling of diagnostics.
-  ProcessWarningOptions(*Diags, *Opts, VFS);
+  ProcessWarningOptions(*Diags, *Opts, *VFS);
 
   return Diags;
 }
@@ -1237,10 +1240,9 @@ compileModuleImpl(CompilerInstance &ImportingInstance, SourceLocation ImportLoc,
   auto &Inv = *Invocation;
   Instance.setInvocation(std::move(Invocation));
 
-  Instance.createDiagnostics(
-      ImportingInstance.getVirtualFileSystem(),
-      new ForwardingDiagnosticConsumer(ImportingInstance.getDiagnosticClient()),
-      /*ShouldOwnClient=*/true);
+  Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
+                                   ImportingInstance.getDiagnosticClient()),
+                             /*ShouldOwnClient=*/true);
 
   if (llvm::is_contained(DiagOpts.SystemHeaderWarningsModules, ModuleName))
     Instance.getDiagnostics().setSuppressSystemWarnings(false);
diff --git a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
index d0b855f..638757a 100644
--- a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
+++ b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -22,7 +22,6 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Option/ArgList.h"
-#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/TargetParser/Host.h"
 using namespace clang;
 using namespace llvm::opt;
@@ -33,9 +32,7 @@ clang::createInvocation(ArrayRef<const char *> ArgList,
   assert(!ArgList.empty());
   auto Diags = Opts.Diags
                    ? std::move(Opts.Diags)
-                   : CompilerInstance::createDiagnostics(
-                         Opts.VFS ? *Opts.VFS : *llvm::vfs::getRealFileSystem(),
-                         new DiagnosticOptions);
+                   : CompilerInstance::createDiagnostics(new DiagnosticOptions);
 
   SmallVector<const char *, 16> Args(ArgList);
 
diff --git a/clang/lib/Frontend/Rewrite/FrontendActions.cpp b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
index 5d2e1d7..6e1f949 100644
--- a/clang/lib/Frontend/Rewrite/FrontendActions.cpp
+++ b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
@@ -247,7 +247,6 @@ public:
     Instance.setInvocation(
         std::make_shared<CompilerInvocation>(CI.getInvocation()));
     Instance.createDiagnostics(
-        CI.getVirtualFileSystem(),
         new ForwardingDiagnosticConsumer(CI.getDiagnosticClient()),
         /*ShouldOwnClient=*/true);
     Instance.getFrontendOpts().DisableFree = false;
diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index 5dc67f6..94f0156 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -15,7 +15,6 @@
 #include "IncrementalExecutor.h"
 #include "IncrementalParser.h"
 #include "InterpreterUtils.h"
-#include "llvm/Support/VirtualFileSystem.h"
 #ifdef __EMSCRIPTEN__
 #include "Wasm.h"
 #endif // __EMSCRIPTEN__
@@ -107,7 +106,7 @@ CreateCI(const llvm::opt::ArgStringList &Argv) {
         CompilerInvocation::GetResourcesPath(Argv[0], nullptr);
 
   // Create the actual diagnostics engine.
-  Clang->createDiagnostics(*llvm::vfs::getRealFileSystem());
+  Clang->createDiagnostics();
   if (!Clang->hasDiagnostics())
     return llvm::createStringError(llvm::errc::not_supported,
                                    "Initialization failed. "
diff --git a/clang/lib/StaticAnalyzer/Frontend/ModelInjector.cpp b/clang/lib/StaticAnalyzer/Frontend/ModelInjector.cpp
index 168c73d..ae11fbb 100644
--- a/clang/lib/StaticAnalyzer/Frontend/ModelInjector.cpp
+++ b/clang/lib/StaticAnalyzer/Frontend/ModelInjector.cpp
@@ -78,7 +78,6 @@ void ModelInjector::onBodySynthesis(const NamedDecl *D) {
   CompilerInstance Instance(CI.getPCHContainerOperations());
   Instance.setInvocation(std::move(Invocation));
   Instance.createDiagnostics(
-      CI.getVirtualFileSystem(),
       new ForwardingDiagnosticConsumer(CI.getDiagnosticClient()),
       /*ShouldOwnClient=*/true);
 
diff --git a/clang/lib/Testing/TestAST.cpp b/clang/lib/Testing/TestAST.cpp
index f7348aa..fe8b938 100644
--- a/clang/lib/Testing/TestAST.cpp
+++ b/clang/lib/Testing/TestAST.cpp
@@ -55,7 +55,7 @@ public:
 // Provides "empty" ASTContext etc if we fail before parsing gets started.
 void createMissingComponents(CompilerInstance &Clang) {
   if (!Clang.hasDiagnostics())
-    Clang.createDiagnostics(*llvm::vfs::getRealFileSystem());
+    Clang.createDiagnostics();
   if (!Clang.hasFileManager())
     Clang.createFileManager();
   if (!Clang.hasSourceManager())
@@ -82,24 +82,9 @@ TestAST::TestAST(const TestInputs &In) {
   auto RecoverFromEarlyExit =
       llvm::make_scope_exit([&] { createMissingComponents(*Clang); });
 
-  std::string Filename = In.FileName;
-  if (Filename.empty())
-    Filename = getFilenameForTesting(In.Language).str();
-
-  // Set up a VFS with only the virtual file visible.
-  auto VFS = llvm::makeIntrusiveRefCnt<llvm::vfs::InMemoryFileSystem>();
-  if (auto Err = VFS->setCurrentWorkingDirectory(In.WorkingDir))
-    ADD_FAILURE() << "Failed to setWD: " << Err.message();
-  VFS->addFile(Filename, /*ModificationTime=*/0,
-               llvm::MemoryBuffer::getMemBufferCopy(In.Code, Filename));
-  for (const auto &Extra : In.ExtraFiles)
-    VFS->addFile(
-        Extra.getKey(), /*ModificationTime=*/0,
-        llvm::MemoryBuffer::getMemBufferCopy(Extra.getValue(), Extra.getKey()));
-
   // Extra error conditions are reported through diagnostics, set that up first.
   bool ErrorOK = In.ErrorOK || llvm::StringRef(In.Code).contains("error-ok");
-  Clang->createDiagnostics(*VFS, new StoreDiagnostics(Diagnostics, !ErrorOK));
+  Clang->createDiagnostics(new StoreDiagnostics(Diagnostics, !ErrorOK));
 
   // Parse cc1 argv, (typically [-std=c++20 input.cc]) into CompilerInvocation.
   std::vector<const char *> Argv;
@@ -108,6 +93,9 @@ TestAST::TestAST(const TestInputs &In) {
     Argv.push_back(S.c_str());
   for (const auto &S : In.ExtraArgs)
     Argv.push_back(S.c_str());
+  std::string Filename = In.FileName;
+  if (Filename.empty())
+    Filename = getFilenameForTesting(In.Language).str();
   Argv.push_back(Filename.c_str());
   Clang->setInvocation(std::make_unique<CompilerInvocation>());
   if (!CompilerInvocation::CreateFromArgs(Clang->getInvocation(), Argv,
@@ -117,6 +105,16 @@ TestAST::TestAST(const TestInputs &In) {
   }
   assert(!Clang->getInvocation().getFrontendOpts().DisableFree);
 
+  // Set up a VFS with only the virtual file visible.
+  auto VFS = llvm::makeIntrusiveRefCnt<llvm::vfs::InMemoryFileSystem>();
+  if (auto Err = VFS->setCurrentWorkingDirectory(In.WorkingDir))
+    ADD_FAILURE() << "Failed to setWD: " << Err.message();
+  VFS->addFile(Filename, /*ModificationTime=*/0,
+               llvm::MemoryBuffer::getMemBufferCopy(In.Code, Filename));
+  for (const auto &Extra : In.ExtraFiles)
+    VFS->addFile(
+        Extra.getKey(), /*ModificationTime=*/0,
+        llvm::MemoryBuffer::getMemBufferCopy(Extra.getValue(), Extra.getKey()));
   Clang->createFileManager(VFS);
 
   // Running the FrontendAction creates the other components: SourceManager,
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
index 5a648df..fd1b7af 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -322,8 +322,7 @@ public:
 
     // Create the compiler's actual diagnostics engine.
     sanitizeDiagOpts(ScanInstance.getDiagnosticOpts());
-    ScanInstance.createDiagnostics(DriverFileMgr->getVirtualFileSystem(),
-                                   DiagConsumer, /*ShouldOwnClient=*/false);
+    ScanInstance.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
     if (!ScanInstance.hasDiagnostics())
       return false;
 
@@ -651,7 +650,7 @@ bool DependencyScanningWorker::computeDependencies(
   auto DiagOpts = CreateAndPopulateDiagOpts(FinalCCommandLine);
   sanitizeDiagOpts(*DiagOpts);
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
-      CompilerInstance::createDiagnostics(*FinalFS, DiagOpts.release(), &DC,
+      CompilerInstance::createDiagnostics(DiagOpts.release(), &DC,
                                           /*ShouldOwnClient=*/false);
 
   // Although `Diagnostics` are used only for command-line parsing, the
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index 88b7349..ffacf9c 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -387,8 +387,7 @@ bool ToolInvocation::run() {
   TextDiagnosticPrinter DiagnosticPrinter(llvm::errs(), DiagOpts);
   IntrusiveRefCntPtr<DiagnosticsEngine> Diagnostics =
       CompilerInstance::createDiagnostics(
-          Files->getVirtualFileSystem(), &*DiagOpts,
-          DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
+          &*DiagOpts, DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
   // Although `Diagnostics` are used only for command-line parsing, the custom
   // `DiagConsumer` might expect a `SourceManager` to be present.
   SourceManager SrcMgr(*Diagnostics, *Files);
@@ -457,8 +456,7 @@ bool FrontendActionFactory::runInvocation(
   std::unique_ptr<FrontendAction> ScopedToolAction(create());
 
   // Create the compiler's actual diagnostics engine.
-  Compiler.createDiagnostics(Files->getVirtualFileSystem(), DiagConsumer,
-                             /*ShouldOwnClient=*/false);
+  Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
   if (!Compiler.hasDiagnostics())
     return false;
 
@@ -654,8 +652,7 @@ public:
                      DiagnosticConsumer *DiagConsumer) override {
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
         Invocation, std::move(PCHContainerOps),
-        CompilerInstance::createDiagnostics(Files->getVirtualFileSystem(),
-                                            &Invocation->getDiagnosticOpts(),
+        CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
                                             DiagConsumer,
                                             /*ShouldOwnClient=*/false),
         Files);