diff --git a/lib/Frontend/DiagnosticRenderer.cpp b/lib/Frontend/DiagnosticRenderer.cpp
index 913aa82..9c4976c 100644
--- a/lib/Frontend/DiagnosticRenderer.cpp
+++ b/lib/Frontend/DiagnosticRenderer.cpp
@@ -69,6 +69,43 @@
   return SM.getImmediateSpellingLoc(Loc);
 }
 
+/// \brief Retrieve the name of the immediate macro expansion.
+///
+/// This routine starts from a source location, and finds the name of the macro
+/// responsible for its immediate expansion. It looks through any intervening
+/// macro argument expansions to compute this. It returns a StringRef which
+/// refers to the SourceManager-owned buffer of the source where that macro
+/// name is spelled. Thus, the result shouldn't out-live that SourceManager.
+///
+/// This differs from Lexer::getImmediateMacroName in that any macro argument
+/// location will result in the topmost function macro that accepted it.
+/// e.g.
+/// \code
+///   MAC1( MAC2(foo) )
+/// \endcode
+/// for location of 'foo' token, this function will return "MAC1" while
+/// Lexer::getImmediateMacroName will return "MAC2".
+static StringRef getImmediateMacroName(SourceLocation Loc,
+                                       const SourceManager &SM,
+                                       const LangOptions &LangOpts) {
+   assert(Loc.isMacroID() && "Only reasonble to call this on macros");
+   // Walk past macro argument expanions.
+   while (SM.isMacroArgExpansion(Loc))
+     Loc = SM.getImmediateExpansionRange(Loc).first;
+
+   // Find the spelling location of the start of the non-argument expansion
+   // range. This is where the macro name was spelled in order to begin
+   // expanding this macro.
+   Loc = SM.getSpellingLoc(SM.getImmediateExpansionRange(Loc).first);
+
+   // Dig out the buffer where the macro name was spelled and the extents of the
+   // name so that we can render it into the expansion note.
+   std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(Loc);
+   unsigned MacroTokenLength = Lexer::MeasureTokenLength(Loc, SM, LangOpts);
+   StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
+   return ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
+}
+
 /// Get the presumed location of a diagnostic message. This computes the
 /// presumed location for the top of any macro backtrace when present.
 static PresumedLoc getDiagnosticPresumedLoc(const SourceManager &SM,
@@ -260,7 +297,7 @@
   llvm::SmallString<100> MessageStorage;
   llvm::raw_svector_ostream Message(MessageStorage);
   Message << "expanded from macro '"
-          << Lexer::getImmediateMacroName(MacroLoc, SM, LangOpts) << "'";
+          << getImmediateMacroName(MacroLoc, SM, LangOpts) << "'";
   emitDiagnostic(SM.getSpellingLoc(Loc), DiagnosticsEngine::Note,
                  Message.str(),
                  Ranges, ArrayRef<FixItHint>());
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 967359f..8ae6e98 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -917,14 +917,40 @@
                                        const SourceManager &SM,
                                        const LangOptions &LangOpts) {
   assert(Loc.isMacroID() && "Only reasonble to call this on macros");
-  // Walk past macro argument expanions.
-  while (SM.isMacroArgExpansion(Loc))
+
+  // Find the location of the immediate macro expansion.
+  while (1) {
+    FileID FID = SM.getFileID(Loc);
+    const SrcMgr::SLocEntry *E = &SM.getSLocEntry(FID);
+    const SrcMgr::ExpansionInfo &Expansion = E->getExpansion();
+    Loc = Expansion.getExpansionLocStart();
+    if (!Expansion.isMacroArgExpansion())
+      break;
+
+    // For macro arguments we need to check that the argument did not come
+    // from an inner macro, e.g: "MAC1( MAC2(foo) )"
+    
+    // Loc points to the argument id of the macro definition, move to the
+    // macro expansion.
     Loc = SM.getImmediateExpansionRange(Loc).first;
+    SourceLocation SpellLoc = Expansion.getSpellingLoc();
+    if (SpellLoc.isFileID())
+      break; // No inner macro.
+
+    // If spelling location resides in the same FileID as macro expansion
+    // location, it means there is no inner macro.
+    FileID MacroFID = SM.getFileID(Loc);
+    if (SM.isInFileID(SpellLoc, MacroFID))
+      break;
+
+    // Argument came from inner macro.
+    Loc = SpellLoc;
+  }
 
   // Find the spelling location of the start of the non-argument expansion
   // range. This is where the macro name was spelled in order to begin
   // expanding this macro.
-  Loc = SM.getSpellingLoc(SM.getImmediateExpansionRange(Loc).first);
+  Loc = SM.getSpellingLoc(Loc);
 
   // Dig out the buffer where the macro name was spelled and the extents of the
   // name so that we can render it into the expansion note.