[clang] [clang-tools-extra] Fix OOM in FormatDiagnostic (PR #108187)

[Vadim D. via cfe-commits]

================
@@ -945,50 +959,11 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> {
 
   void Report(const StoredDiagnostic &storedDiag);
 
-  /// Determine whethere there is already a diagnostic in flight.
-  bool isDiagnosticInFlight() const {
-    return CurDiagID != std::numeric_limits<unsigned>::max();
-  }
-
-  /// Set the "delayed" diagnostic that will be emitted once
-  /// the current diagnostic completes.
-  ///
-  ///  If a diagnostic is already in-flight but the front end must
-  ///  report a problem (e.g., with an inconsistent file system
-  ///  state), this routine sets a "delayed" diagnostic that will be
-  ///  emitted after the current diagnostic completes. This should
-  ///  only be used for fatal errors detected at inconvenient
-  ///  times. If emitting a delayed diagnostic causes a second delayed
-  ///  diagnostic to be introduced, that second delayed diagnostic
-  ///  will be ignored.
-  ///
-  /// \param DiagID The ID of the diagnostic being delayed.
-  ///
-  /// \param Arg1 A string argument that will be provided to the
-  /// diagnostic. A copy of this string will be stored in the
-  /// DiagnosticsEngine object itself.
-  ///
-  /// \param Arg2 A string argument that will be provided to the
-  /// diagnostic. A copy of this string will be stored in the
-  /// DiagnosticsEngine object itself.
-  ///
-  /// \param Arg3 A string argument that will be provided to the
-  /// diagnostic. A copy of this string will be stored in the
-  /// DiagnosticsEngine object itself.
-  void SetDelayedDiagnostic(unsigned DiagID, StringRef Arg1 = "",
-                            StringRef Arg2 = "", StringRef Arg3 = "");
-
-  /// Clear out the current diagnostic.
-  void Clear() { CurDiagID = std::numeric_limits<unsigned>::max(); }
-
-  /// Return the value associated with this diagnostic flag.
-  StringRef getFlagValue() const { return FlagValue; }
-
 private:
   // This is private state used by DiagnosticBuilder.  We put it here instead of
   // in DiagnosticBuilder in order to keep DiagnosticBuilder a small lightweight
-  // object.  This implementation choice means that we can only have one
-  // diagnostic "in flight" at a time, but this seems to be a reasonable
+  // object.  This implementation choice means that we can only have a few
+  // diagnostics "in flight" at a time, but this seems to be a reasonable
   // tradeoff to keep these objects small.  Assertions verify that only one
   // diagnostic is in flight at a time.
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vvd170501 wrote:

"Assertions verify that only one diagnostic is in flight at a time" is now outdated and can be removed.

https://github.com/llvm/llvm-project/pull/108187