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

Starting with 41e3919 DiagnosticsEngine
creation might perform IO. It was implicitly defaulting to
getRealFileSystem. This patch makes it explicit by pushing the decision
making to callers.

It uses ambient VFS if one is available, and keeps using
`getRealFileSystem` if there aren't any VFS.

Author: kadircet

clang-tools-extra/clang-include-fixer/IncludeFixer.cpp

@@ -95,7 +95,8 @@ bool IncludeFixerActionFactory::runInvocation(
 
   // Create the compiler's actual diagnostics engine. We want to drop all
   // diagnostics here.
-  Compiler.createDiagnostics(new clang::IgnoringDiagConsumer,
+  Compiler.createDiagnostics(Files->getVirtualFileSystem(),
+                             new clang::IgnoringDiagConsumer,
                              /*ShouldOwnClient=*/true);
   Compiler.createSourceManager(*Files);
 

clang-tools-extra/clangd/Compiler.cpp

@@ -110,8 +110,8 @@ buildCompilerInvocation(const ParseInputs &Inputs, clang::DiagnosticConsumer &D,
   CIOpts.VFS = Inputs.TFS->view(Inputs.CompileCommand.Directory);
   CIOpts.CC1Args = CC1Args;
   CIOpts.RecoverOnError = true;
-  CIOpts.Diags =
-      CompilerInstance::createDiagnostics(new DiagnosticOptions, &D, false);
+  CIOpts.Diags = CompilerInstance::createDiagnostics(
+      *CIOpts.VFS, new DiagnosticOptions, &D, false);
   CIOpts.ProbePrecompiled = false;
   std::unique_ptr<CompilerInvocation> CI = createInvocation(ArgStrs, CIOpts);
   if (!CI)
@@ -148,7 +148,7 @@ prepareCompilerInstance(std::unique_ptr<clang::CompilerInvocation> CI,
   auto Clang = std::make_unique<CompilerInstance>(
       std::make_shared<PCHContainerOperations>());
   Clang->setInvocation(std::move(CI));
-  Clang->createDiagnostics(&DiagsClient, false);
+  Clang->createDiagnostics(*VFS, &DiagsClient, false);
 
   if (auto VFSWithRemapping = createVFSFromCompilerInvocation(
           Clang->getInvocation(), Clang->getDiagnostics(), VFS))

clang-tools-extra/clangd/ModulesBuilder.cpp

@@ -188,7 +188,8 @@ bool IsModuleFileUpToDate(PathRef ModuleFilePath,
 
   clang::clangd::IgnoreDiagnostics IgnoreDiags;
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
-      CompilerInstance::createDiagnostics(new DiagnosticOptions, &IgnoreDiags,
+      CompilerInstance::createDiagnostics(*VFS, new DiagnosticOptions,
+                                          &IgnoreDiags,
                                           /*ShouldOwnClient=*/false);
 
   LangOptions LangOpts;

clang-tools-extra/clangd/Preamble.cpp

@@ -613,8 +613,9 @@ buildPreamble(PathRef FileName, CompilerInvocation CI,
         for (const auto &L : ASTListeners)
           L->sawDiagnostic(D, Diag);
       });
+  auto VFS = Inputs.TFS->view(Inputs.CompileCommand.Directory);
   llvm::IntrusiveRefCntPtr<DiagnosticsEngine> PreambleDiagsEngine =
-      CompilerInstance::createDiagnostics(&CI.getDiagnosticOpts(),
+      CompilerInstance::createDiagnostics(*VFS, &CI.getDiagnosticOpts(),
                                           &PreambleDiagnostics,
                                           /*ShouldOwnClient=*/false);
   const Config &Cfg = Config::current();
@@ -651,7 +652,6 @@ buildPreamble(PathRef FileName, CompilerInvocation CI,
         for (const auto &L : ASTListeners)
           L->beforeExecute(CI);
       });
-  auto VFS = Inputs.TFS->view(Inputs.CompileCommand.Directory);
   llvm::SmallString<32> AbsFileName(FileName);
   VFS->makeAbsolute(AbsFileName);
   auto StatCache = std::make_shared<PreambleFileStatusCache>(AbsFileName);

clang-tools-extra/include-cleaner/unittests/RecordTest.cpp

@@ -609,15 +609,6 @@ TEST_F(PragmaIncludeTest, ExportInUnnamedBuffer) {
   )cpp";
   Inputs.ExtraFiles["foo.h"] = "";
 
-  auto Clang = std::make_unique<CompilerInstance>(
-      std::make_shared<PCHContainerOperations>());
-  Clang->createDiagnostics();
-
-  Clang->setInvocation(std::make_unique<CompilerInvocation>());
-  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(
-      Clang->getInvocation(), {Filename.data()}, Clang->getDiagnostics(),
-      "clang"));
-
   // Create unnamed memory buffers for all the files.
   auto VFS = llvm::makeIntrusiveRefCnt<llvm::vfs::InMemoryFileSystem>();
   VFS->addFile(Filename, /*ModificationTime=*/0,
@@ -626,6 +617,16 @@ TEST_F(PragmaIncludeTest, ExportInUnnamedBuffer) {
     VFS->addFile(Extra.getKey(), /*ModificationTime=*/0,
                  llvm::MemoryBuffer::getMemBufferCopy(Extra.getValue(),
                                                       /*BufferName=*/""));
+
+  auto Clang = std::make_unique<CompilerInstance>(
+      std::make_shared<PCHContainerOperations>());
+  Clang->createDiagnostics(*VFS);
+
+  Clang->setInvocation(std::make_unique<CompilerInvocation>());
+  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(
+      Clang->getInvocation(), {Filename.data()}, Clang->getDiagnostics(),
+      "clang"));
+
   auto *FM = Clang->createFileManager(VFS);
   ASSERT_TRUE(Clang->ExecuteAction(*Inputs.MakeAction()));
   EXPECT_THAT(

clang/include/clang/Frontend/CompilerInstance.h

@@ -675,13 +675,17 @@ class CompilerInstance : public ModuleLoader {
   /// Note that this routine also replaces the diagnostic client,
   /// allocating one if one is not provided.
   ///
+  /// \param VFS is used for any IO needed when creating DiagnosticsEngine. It
+  /// doesn't replace VFS in the CompilerInstance (if any).
+  ///
   /// \param Client If non-NULL, a diagnostic client that will be
   /// attached to (and, then, owned by) the DiagnosticsEngine inside this AST
   /// unit.
   ///
   /// \param ShouldOwnClient If Client is non-NULL, specifies whether
   /// the diagnostic object should take ownership of the client.
-  void createDiagnostics(DiagnosticConsumer *Client = nullptr,
+  void createDiagnostics(llvm::vfs::FileSystem &VFS,
+                         DiagnosticConsumer *Client = nullptr,
                          bool ShouldOwnClient = true);
 
   /// Create a DiagnosticsEngine object with a the TextDiagnosticPrinter.
@@ -702,10 +706,11 @@ class CompilerInstance : public ModuleLoader {
   /// used by some diagnostics printers (for logging purposes only).
   ///
   /// \return The new object on success, or null on failure.
-  static IntrusiveRefCntPtr<DiagnosticsEngine> createDiagnostics(
-      DiagnosticOptions *Opts, DiagnosticConsumer *Client = nullptr,
-      bool ShouldOwnClient = true, const CodeGenOptions *CodeGenOpts = nullptr,
-      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
+  static IntrusiveRefCntPtr<DiagnosticsEngine>
+  createDiagnostics(llvm::vfs::FileSystem &VFS, DiagnosticOptions *Opts,
+                    DiagnosticConsumer *Client = nullptr,
+                    bool ShouldOwnClient = true,
+                    const CodeGenOptions *CodeGenOpts = nullptr);
 
   /// Create the file manager and replace any existing one with it.
   ///

clang/lib/Frontend/CompilerInstance.cpp

@@ -332,23 +332,20 @@ static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
   }
 }
 
-void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
+void CompilerInstance::createDiagnostics(llvm::vfs::FileSystem &VFS,
+                                         DiagnosticConsumer *Client,
                                          bool ShouldOwnClient) {
-  Diagnostics = createDiagnostics(
-      &getDiagnosticOpts(), Client, ShouldOwnClient, &getCodeGenOpts(),
-      FileMgr ? FileMgr->getVirtualFileSystemPtr() : nullptr);
+  Diagnostics = createDiagnostics(VFS, &getDiagnosticOpts(), Client,
+                                  ShouldOwnClient, &getCodeGenOpts());
 }
 
 IntrusiveRefCntPtr<DiagnosticsEngine> CompilerInstance::createDiagnostics(
-    DiagnosticOptions *Opts, DiagnosticConsumer *Client, bool ShouldOwnClient,
-    const CodeGenOptions *CodeGenOpts,
-    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
+    llvm::vfs::FileSystem &VFS, DiagnosticOptions *Opts,
+    DiagnosticConsumer *Client, bool ShouldOwnClient,
+    const CodeGenOptions *CodeGenOpts) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
-  IntrusiveRefCntPtr<DiagnosticsEngine>
-      Diags(new DiagnosticsEngine(DiagID, Opts));
-
-  if (!VFS)
-    VFS = llvm::vfs::getRealFileSystem();
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
+      new DiagnosticsEngine(DiagID, Opts));
 
   // Create the diagnostic client for reporting errors or for
   // implementing -verify.
@@ -372,7 +369,7 @@ IntrusiveRefCntPtr<DiagnosticsEngine> CompilerInstance::createDiagnostics(
                                Opts->DiagnosticSerializationFile);
 
   // Configure our handling of diagnostics.
-  ProcessWarningOptions(*Diags, *Opts, *VFS);
+  ProcessWarningOptions(*Diags, *Opts, VFS);
 
   return Diags;
 }
@@ -1240,9 +1237,10 @@ compileModuleImpl(CompilerInstance &ImportingInstance, SourceLocation ImportLoc,
   auto &Inv = *Invocation;
   Instance.setInvocation(std::move(Invocation));
 
-  Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
-                                   ImportingInstance.getDiagnosticClient()),
-                             /*ShouldOwnClient=*/true);
+  Instance.createDiagnostics(
+      ImportingInstance.getVirtualFileSystem(),
+      new ForwardingDiagnosticConsumer(ImportingInstance.getDiagnosticClient()),
+      /*ShouldOwnClient=*/true);
 
   if (llvm::is_contained(DiagOpts.SystemHeaderWarningsModules, ModuleName))
     Instance.getDiagnostics().setSuppressSystemWarnings(false);

clang/lib/Frontend/CreateInvocationFromCommandLine.cpp

@@ -22,6 +22,7 @@
 #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;
@@ -32,7 +33,9 @@ clang::createInvocation(ArrayRef<const char *> ArgList,
   assert(!ArgList.empty());
   auto Diags = Opts.Diags
                    ? std::move(Opts.Diags)
-                   : CompilerInstance::createDiagnostics(new DiagnosticOptions);
+                   : CompilerInstance::createDiagnostics(
+                         Opts.VFS ? *Opts.VFS : *llvm::vfs::getRealFileSystem(),
+                         new DiagnosticOptions);
 
   SmallVector<const char *, 16> Args(ArgList);
 

clang/lib/Frontend/Rewrite/FrontendActions.cpp

@@ -247,6 +247,7 @@ class RewriteIncludesAction::RewriteImportsListener : public ASTReaderListener {
     Instance.setInvocation(
         std::make_shared<CompilerInvocation>(CI.getInvocation()));
     Instance.createDiagnostics(
+        CI.getVirtualFileSystem(),
         new ForwardingDiagnosticConsumer(CI.getDiagnosticClient()),
         /*ShouldOwnClient=*/true);
     Instance.getFrontendOpts().DisableFree = false;

clang/lib/Interpreter/Interpreter.cpp

@@ -15,6 +15,7 @@
 #include "IncrementalExecutor.h"
 #include "IncrementalParser.h"
 #include "InterpreterUtils.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #ifdef __EMSCRIPTEN__
 #include "Wasm.h"
 #endif // __EMSCRIPTEN__
@@ -106,7 +107,7 @@ CreateCI(const llvm::opt::ArgStringList &Argv) {
         CompilerInvocation::GetResourcesPath(Argv[0], nullptr);
 
   // Create the actual diagnostics engine.
-  Clang->createDiagnostics();
+  Clang->createDiagnostics(*llvm::vfs::getRealFileSystem());
   if (!Clang->hasDiagnostics())
     return llvm::createStringError(llvm::errc::not_supported,
                                    "Initialization failed. "