7 files changed, 46 insertions, 2 deletions

diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 605e6cc7d97..e56cfda056b 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -149,6 +149,7 @@ def IncompatiblePointerTypes
   : DiagGroup<"incompatible-pointer-types",
     [IncompatiblePointerTypesDiscardsQualifiers]>;
 def IncompleteUmbrella : DiagGroup<"incomplete-umbrella">;
+def IncompleteModule : DiagGroup<"incomplete-module", [IncompleteUmbrella]>;
 def InvalidNoreturn : DiagGroup<"invalid-noreturn">;
 def InvalidSourceEncoding : DiagGroup<"invalid-source-encoding">;
 def KNRPromotedParameter : DiagGroup<"knr-promoted-parameter">;
diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
index 2c16000d339..6d4008c5e76 100644
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -579,7 +579,10 @@ def warn_auto_module_import : Warning<
   "import of module '%1'">, InGroup<AutoImport>, DefaultIgnore;
 def warn_uncovered_module_header : Warning<
   "umbrella header for module '%0' does not include header '%1'">, 
-  InGroup<IncompleteUmbrella>;
+  InGroup<IncompleteUmbrella>, DefaultIgnore;
+def warn_forgotten_module_header : Warning<
+  "header '%0' is included in module '%1' but not listed in module map">,
+  InGroup<IncompleteModule>, DefaultIgnore;
 def err_expected_id_building_module : Error<
   "expected a module name in '__building_module' expression">;
   
diff --git a/clang/lib/Lex/PPLexerChange.cpp b/clang/lib/Lex/PPLexerChange.cpp
index a22d67a6edf..deec5a8766c 100644
--- a/clang/lib/Lex/PPLexerChange.cpp
+++ b/clang/lib/Lex/PPLexerChange.cpp
@@ -401,8 +401,36 @@ bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
         }
       }
     }
+
+    // Check whether there are any headers that were included, but not
+    // mentioned at all in the module map. Such headers 
+    SourceLocation StartLoc
+      = SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID());
+    if (getDiagnostics().getDiagnosticLevel(diag::warn_forgotten_module_header,
+                                            StartLoc)
+          != DiagnosticsEngine::Ignored) {
+      ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
+      for (unsigned I = 0, N = SourceMgr.local_sloc_entry_size(); I != N; ++I) {
+        // We only care about file entries.
+        const SrcMgr::SLocEntry &Entry = SourceMgr.getLocalSLocEntry(I);
+        if (!Entry.isFile())
+          continue;
+
+        // Dig out the actual file.
+        const FileEntry *File = Entry.getFile().getContentCache()->OrigEntry;
+        if (!File)
+          continue;
+
+        // If it's not part of a module and not unknown, complain.
+        if (!ModMap.findModuleForHeader(File) &&
+            !ModMap.isHeaderInUnavailableModule(File)) {
+          Diag(StartLoc, diag::warn_forgotten_module_header)
+            << File->getName() << Mod->getFullModuleName();
+        }
+      }
+    }
   }
-  
+
   return true;
 }
 
diff --git a/clang/test/Modules/Inputs/incomplete_mod.h b/clang/test/Modules/Inputs/incomplete_mod.h
new file mode 100644
index 00000000000..f08be724413
--- /dev/null
+++ b/clang/test/Modules/Inputs/incomplete_mod.h
@@ -0,0 +1 @@
+#include "incomplete_mod_missing.h"
diff --git a/clang/test/Modules/Inputs/incomplete_mod_missing.h b/clang/test/Modules/Inputs/incomplete_mod_missing.h
new file mode 100644
index 00000000000..ffc85d5e730
--- /dev/null
+++ b/clang/test/Modules/Inputs/incomplete_mod_missing.h
@@ -0,0 +1,2 @@
+extern int *missing;
+
diff --git a/clang/test/Modules/Inputs/module.map b/clang/test/Modules/Inputs/module.map
index d20521f9c76..249700a494a 100644
--- a/clang/test/Modules/Inputs/module.map
+++ b/clang/test/Modules/Inputs/module.map
@@ -209,3 +209,7 @@ module linkage_merge {
   }
 
 }
+
+module incomplete_mod {
+  header "incomplete_mod.h"
+}
diff --git a/clang/test/Modules/incomplete-module.m b/clang/test/Modules/incomplete-module.m
new file mode 100644
index 00000000000..8edaea983cb
--- /dev/null
+++ b/clang/test/Modules/incomplete-module.m
@@ -0,0 +1,5 @@
+@import incomplete_mod;
+
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t -Wincomplete-module -fmodules -I %S/Inputs %s 2>&1 | FileCheck %s
+// CHECK: {{warning: header '.*incomplete_mod_missing.h' is included in module 'incomplete_mod' but not listed in module map}}