6 files changed, 21 insertions, 8 deletions
diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index b77ddcb6c05..7eff0a4216a 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -653,6 +653,12 @@ enum CXDiagnosticSeverity {
   CXDiagnostic_Note    = 1,
 
   /**
+   * \brief This diagnostic is a remark that provides additional information
+   * for the user.
+   */
+  CXDiagnostic_Remark = 5,
+
+  /**
    * \brief This diagnostic indicates suspicious code that may not be
    * wrong.
    */
diff --git a/clang/include/clang/Basic/Diagnostic.h b/clang/include/clang/Basic/Diagnostic.h
index 6782964df66..d83c4c0b9b4 100644
--- a/clang/include/clang/Basic/Diagnostic.h
+++ b/clang/include/clang/Basic/Diagnostic.h
@@ -142,6 +142,7 @@ public:
   enum Level {
     Ignored = DiagnosticIDs::Ignored,
     Note = DiagnosticIDs::Note,
+    Remark = DiagnosticIDs::Remark,
     Warning = DiagnosticIDs::Warning,
     Error = DiagnosticIDs::Error,
     Fatal = DiagnosticIDs::Fatal
diff --git a/clang/include/clang/Basic/Diagnostic.td b/clang/include/clang/Basic/Diagnostic.td
index 2616548bc00..61a4508615e 100644
--- a/clang/include/clang/Basic/Diagnostic.td
+++ b/clang/include/clang/Basic/Diagnostic.td
@@ -15,6 +15,7 @@
 // Define the diagnostic mappings.
 class DiagMapping;
 def MAP_IGNORE  : DiagMapping;
+def MAP_REMARK  : DiagMapping;
 def MAP_WARNING : DiagMapping;
 def MAP_ERROR   : DiagMapping;
 def MAP_FATAL   : DiagMapping;
@@ -22,6 +23,7 @@ def MAP_FATAL   : DiagMapping;
 // Define the diagnostic classes.
 class DiagClass;
 def CLASS_NOTE      : DiagClass;
+def CLASS_REMARK    : DiagClass;
 def CLASS_WARNING   : DiagClass;
 def CLASS_EXTENSION : DiagClass;
 def CLASS_ERROR     : DiagClass;
@@ -84,6 +86,7 @@ class AccessControl {
 // FIXME: ExtWarn and Extension should also be SFINAEFailure by default.
 class Error<string str>     : Diagnostic<str, CLASS_ERROR, MAP_ERROR>, SFINAEFailure;
 class Warning<string str>   : Diagnostic<str, CLASS_WARNING, MAP_WARNING>;
+class Remark<string str>    : Diagnostic<str, CLASS_REMARK, MAP_IGNORE>;
 class Extension<string str> : Diagnostic<str, CLASS_EXTENSION, MAP_IGNORE>;
 class ExtWarn<string str>   : Diagnostic<str, CLASS_EXTENSION, MAP_WARNING>;
 class Note<string str>      : Diagnostic<str, CLASS_NOTE, MAP_FATAL/*ignored*/>;
diff --git a/clang/include/clang/Basic/DiagnosticFrontendKinds.td b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
index 2b36d38a3f1..41a83a0b8ed 100644
--- a/clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -29,6 +29,7 @@ def note_fe_backend_frame_larger_than: Note<"%0">, CatBackend;
 
 def warn_fe_backend_plugin: Warning<"%0">, CatBackend, InGroup<BackendPlugin>;
 def err_fe_backend_plugin: Error<"%0">, CatBackend;
+def remark_fe_backend_plugin: Remark<"%0">, CatBackend, InGroup<RemarkBackendPlugin>;
 def note_fe_backend_plugin: Note<"%0">, CatBackend;
 
 def err_fe_invalid_code_complete_file : Error<
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 428363bcfc5..9ec2f421cda 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -637,3 +637,4 @@ def SourceUsesOpenMP : DiagGroup<"source-uses-openmp">;
 def BackendInlineAsm : DiagGroup<"inline-asm">;
 def BackendFrameLargerThan : DiagGroup<"frame-larger-than">;
 def BackendPlugin : DiagGroup<"backend-plugin">;
+def RemarkBackendPlugin : DiagGroup<"remark-backend-plugin">;
diff --git a/clang/include/clang/Basic/DiagnosticIDs.h b/clang/include/clang/Basic/DiagnosticIDs.h
index 0152f25fa66..f9b845606bc 100644
--- a/clang/include/clang/Basic/DiagnosticIDs.h
+++ b/clang/include/clang/Basic/DiagnosticIDs.h
@@ -56,16 +56,17 @@ namespace clang {
     };
 
     /// Enum values that allow the client to map NOTEs, WARNINGs, and EXTENSIONs
-    /// to either MAP_IGNORE (nothing), MAP_WARNING (emit a warning), MAP_ERROR
-    /// (emit as an error).  It allows clients to map errors to
-    /// MAP_ERROR/MAP_DEFAULT or MAP_FATAL (stop emitting diagnostics after this
-    /// one).
+    /// to either MAP_IGNORE (nothing), MAP_REMARK (emit a remark), MAP_WARNING
+    /// (emit a warning), MAP_ERROR (emit as an error).  It allows clients to
+    /// map errors to MAP_ERROR/MAP_DEFAULT or MAP_FATAL (stop emitting
+    /// diagnostics after this one).
     enum Mapping {
       // NOTE: 0 means "uncomputed".
       MAP_IGNORE  = 1,     ///< Map this diagnostic to nothing, ignore it.
-      MAP_WARNING = 2,     ///< Map this diagnostic to a warning.
-      MAP_ERROR   = 3,     ///< Map this diagnostic to an error.
-      MAP_FATAL   = 4      ///< Map this diagnostic to a fatal error.
+      MAP_REMARK  = 2,     ///< Map this diagnostic to a remark.
+      MAP_WARNING = 3,     ///< Map this diagnostic to a warning.
+      MAP_ERROR   = 4,     ///< Map this diagnostic to an error.
+      MAP_FATAL   = 5      ///< Map this diagnostic to a fatal error.
     };
   }
 
@@ -113,7 +114,7 @@ class DiagnosticIDs : public RefCountedBase<DiagnosticIDs> {
 public:
   /// \brief The level of the diagnostic, after it has been through mapping.
   enum Level {
-    Ignored, Note, Warning, Error, Fatal
+    Ignored, Note, Remark, Warning, Error, Fatal
   };
 
 private: