6 files changed, 21 insertions, 14 deletions
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index fe47c3a9c8..b1f4fb62dc 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3284,10 +3284,12 @@ def note_deleted_assign_field : Note<
   "%select{copy|move}0 assignment operator of %1 is implicitly deleted "
   "because field %2 is of %select{reference|const-qualified}4 type %3">;
 
-// This should eventually be an error.
+// These should be errors.
 def warn_undefined_internal : Warning<
   "%select{function|variable}0 %q1 has internal linkage but is not defined">,
   InGroup<DiagGroup<"undefined-internal">>;
+def warn_undefined_inline : Warning<"inline function %q0 is not defined">,
+  InGroup<DiagGroup<"undefined-inline">>;
 def note_used_here : Note<"used here">;
 
 def warn_internal_in_extern_inline : ExtWarn<
diff --git a/include/clang/Sema/ExternalSemaSource.h b/include/clang/Sema/ExternalSemaSource.h
index 6693dc8683..cbce757ea7 100644
--- a/include/clang/Sema/ExternalSemaSource.h
+++ b/include/clang/Sema/ExternalSemaSource.h
@@ -67,9 +67,11 @@ public:
   virtual void ReadKnownNamespaces(
                            SmallVectorImpl<NamespaceDecl *> &Namespaces);
 
-  virtual void ReadUndefinedInternals(
+  /// \brief Load the set of used but not defined functions or variables with
+  /// internal linkage, or used but not defined internal functions.
+  virtual void ReadUndefinedButUsed(
                          llvm::DenseMap<NamedDecl*, SourceLocation> &Undefined);
-  
+
   /// \brief Do last resort, unqualified lookup on a LookupResult that
   /// Sema cannot find.
   ///
diff --git a/include/clang/Sema/MultiplexExternalSemaSource.h b/include/clang/Sema/MultiplexExternalSemaSource.h
index 494ba656bb..32b7276c83 100644
--- a/include/clang/Sema/MultiplexExternalSemaSource.h
+++ b/include/clang/Sema/MultiplexExternalSemaSource.h
@@ -253,7 +253,9 @@ public:
   /// which will be used during typo correction.
   virtual void ReadKnownNamespaces(SmallVectorImpl<NamespaceDecl*> &Namespaces);
 
-  virtual void ReadUndefinedInternals(
+  /// \brief Load the set of used but not defined functions or variables with
+  /// internal linkage, or used but not defined inline functions.
+  virtual void ReadUndefinedButUsed(
                          llvm::DenseMap<NamedDecl*, SourceLocation> &Undefined);
   
   /// \brief Do last resort, unqualified lookup on a LookupResult that
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index d0d3ff937d..da80f0c8df 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -738,12 +738,12 @@ public:
   // argument locations.
   llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;
 
-  /// UndefinedInternals - all the used, undefined objects with
-  /// internal linkage in this translation unit.
-  llvm::DenseMap<NamedDecl *, SourceLocation> UndefinedInternals;
+  /// UndefinedInternals - all the used, undefined objects which require a
+  /// definition in this translation unit.
+  llvm::DenseMap<NamedDecl *, SourceLocation> UndefinedButUsed;
 
   /// Obtain a sorted list of functions that are undefined but ODR-used.
-  void getUndefinedInternals(
+  void getUndefinedButUsed(
     llvm::SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);
 
   typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 166434201c..6f76367342 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -526,9 +526,9 @@ namespace clang {
       /// being deserialized.
       MACRO_UPDATES = 48,
 
-      /// \brief Record code for undefined but used internal functions and
-      /// variables.
-      UNDEFINED_INTERNALS = 49
+      /// \brief Record code for undefined but used functions and variables that
+      /// need a definition in this TU.
+      UNDEFINED_BUT_USED = 49
     };
 
     /// \brief Record types used within a source manager block.
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index aa3633b4b3..d3f3466c33 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -677,8 +677,9 @@ private:
   /// \brief A list of the namespaces we've seen.
   SmallVector<uint64_t, 4> KnownNamespaces;
 
-  /// \brief A list of undefined decls with internal linkage.
-  SmallVector<uint64_t, 8> UndefinedInternals;
+  /// \brief A list of undefined decls with internal linkage followed by the
+  /// SourceLocation of a matching ODR-use.
+  SmallVector<uint64_t, 8> UndefinedButUsed;
 
   /// \brief A list of modules that were imported by precompiled headers or
   /// any other non-module AST file.
@@ -1520,7 +1521,7 @@ public:
   virtual void ReadKnownNamespaces(
                            SmallVectorImpl<NamespaceDecl *> &Namespaces);
 
-  virtual void ReadUndefinedInternals(
+  virtual void ReadUndefinedButUsed(
                         llvm::DenseMap<NamedDecl *, SourceLocation> &Undefined);
 
   virtual void ReadTentativeDefinitions(