Index: include/clang/Basic/DiagnosticIDs.h
===================================================================
--- include/clang/Basic/DiagnosticIDs.h
+++ include/clang/Basic/DiagnosticIDs.h
@@ -217,6 +217,8 @@
   /// or 0 if no category.
   static unsigned getCategoryNumberForDiag(unsigned DiagID);
 
+  static StringRef getDiagIDName(unsigned DiagID);
+
   /// \brief Return the number of diagnostic categories.
   static unsigned getNumberOfCategories();
 
Index: include/clang/Basic/DiagnosticOptions.def
===================================================================
--- include/clang/Basic/DiagnosticOptions.def
+++ include/clang/Basic/DiagnosticOptions.def
@@ -61,6 +61,7 @@
 DIAGOPT(ShowNoteIncludeStack, 1, 0) /// Show include stacks for notes.
 VALUE_DIAGOPT(ShowCategories, 2, 0) /// Show categories: 0 -> none, 1 -> Number,
                                     /// 2 -> Full Name.
+DIAGOPT(ShowDiagIDs, 1, 0) /// Show Diagnostic ID
                                  
 ENUM_DIAGOPT(Format, TextDiagnosticFormat, 2, Clang) /// Format for diagnostics: 
   
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -742,6 +742,10 @@
     Group<f_Group>,  Flags<[CC1Option]>, HelpText<"Display include stacks for diagnostic notes">;
 def fdiagnostics_format_EQ : Joined<["-"], "fdiagnostics-format=">, Group<f_clang_Group>;
 def fdiagnostics_show_category_EQ : Joined<["-"], "fdiagnostics-show-category=">, Group<f_clang_Group>;
+def fdiagnostics_show_diag_ids : Flag<["-"], "fdiagnostics-show-diag-ids">,
+    Group<f_clang_Group>, Flags<[CC1Option]>;
+def fno_diagnostics_show_diag_ids : Flag<["-"], "fno-diagnostics-show-diag-ids">,
+    Group<f_clang_Group>, Flags<[CC1Option]>;
 def fdiagnostics_show_template_tree : Flag<["-"], "fdiagnostics-show-template-tree">,
     Group<f_Group>, Flags<[CC1Option]>,
     HelpText<"Print a template comparison tree for differing templates">;
Index: lib/Basic/DiagnosticIDs.cpp
===================================================================
--- lib/Basic/DiagnosticIDs.cpp
+++ lib/Basic/DiagnosticIDs.cpp
@@ -37,6 +37,7 @@
 };
 
 struct StaticDiagInfoRec {
+  const char *IDName;
   uint16_t DiagID;
   unsigned DefaultSeverity : 3;
   unsigned Class : 3;
@@ -74,8 +75,9 @@
 #define DIAG(ENUM, CLASS, DEFAULT_SEVERITY, DESC, GROUP, SFINAE, NOWERROR,     \
              SHOWINSYSHEADER, CATEGORY)                                        \
   {                                                                            \
-    diag::ENUM, DEFAULT_SEVERITY, CLASS, DiagnosticIDs::SFINAE, NOWERROR,      \
-        SHOWINSYSHEADER, CATEGORY, GROUP, STR_SIZE(DESC, uint16_t), DESC       \
+    #ENUM, diag::ENUM, DEFAULT_SEVERITY, CLASS, DiagnosticIDs::SFINAE,         \
+        NOWERROR, SHOWINSYSHEADER, CATEGORY, GROUP, STR_SIZE(DESC, uint16_t),  \
+        DESC                                                                   \
   }                                                                            \
   ,
 #include "clang/Basic/DiagnosticCommonKinds.inc"
@@ -179,6 +181,12 @@
   return 0;
 }
 
+StringRef DiagnosticIDs::getDiagIDName(unsigned DiagID) {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return StringRef(Info->IDName);
+  return StringRef();
+}
+
 namespace {
   // The diagnostic category names.
   struct StaticDiagCategoryRec {
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -4046,6 +4046,11 @@
     CmdArgs.push_back(A->getValue());
   }
 
+  if (Args.hasFlag(options::OPT_fdiagnostics_show_diag_ids,
+                   options::OPT_fno_diagnostics_show_diag_ids, false)) {
+    CmdArgs.push_back("-fdiagnostics-show-diag-ids");
+  }
+
   if (Args.hasFlag(options::OPT_fdiagnostics_show_hotness,
                    options::OPT_fno_diagnostics_show_hotness, false))
     CmdArgs.push_back("-fdiagnostics-show-hotness");
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1079,6 +1079,8 @@
       << ShowCategory;
   }
 
+  Opts.ShowDiagIDs = Args.hasArg(OPT_fdiagnostics_show_diag_ids);
+
   StringRef Format =
     Args.getLastArgValue(OPT_fdiagnostics_format, "clang");
   if (Format == "clang")
Index: lib/Frontend/TextDiagnosticPrinter.cpp
===================================================================
--- lib/Frontend/TextDiagnosticPrinter.cpp
+++ lib/Frontend/TextDiagnosticPrinter.cpp
@@ -19,6 +19,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Signals.h"
 #include <algorithm>
 using namespace clang;
 
@@ -103,6 +104,13 @@
       }
     }
   }
+  // If the user wants to see diagnostic ids, include it too.
+  if (DiagOpts.ShowDiagIDs) {
+    OS << (Started ? "," : " [");
+    Started = true;
+    OS << DiagnosticIDs::getDiagIDName(Info.getID()) << ":" << Info.getID();
+  }
+
   if (Started)
     OS << ']';
 }