[clang] [clang-tools-extra] [clang] Initialize the file system explicitly (PR #158381)

[Jan Svoboda via cfe-commits]

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@@ -650,32 +675,31 @@ 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(llvm::vfs::FileSystem &VFS,
-                         DiagnosticConsumer *Client = nullptr,
+  void createDiagnostics(DiagnosticConsumer *Client = nullptr,
                          bool ShouldOwnClient = true);
 
-  /// Create a DiagnosticsEngine object with a the TextDiagnosticPrinter.
+  /// Create a DiagnosticsEngine object.
   ///
   /// If no diagnostic client is provided, this creates a
   /// DiagnosticConsumer that is owned by the returned diagnostic
   /// object, if using directly the caller is responsible for
   /// releasing the returned DiagnosticsEngine's client eventually.
   ///
+  /// \param VFS The file system used to load the suppression mappings file.
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jansvoboda11 wrote:

This is a static function, so this one doesn't have access to the instance's VFS.

https://github.com/llvm/llvm-project/pull/158381