Index: clang/lib/Lex/PPDirectives.cpp
===================================================================
--- clang/lib/Lex/PPDirectives.cpp
+++ clang/lib/Lex/PPDirectives.cpp
@@ -164,6 +164,7 @@
         "_THREAD_SAFE",
         "_XOPEN_SOURCE",
         "_XOPEN_SOURCE_EXTENDED",
+        "__GCC_HAVE_DWARF2_CFI_ASM",
         "__STDCPP_WANT_MATH_SPEC_FUNCS__",
         "__STDC_FORMAT_MACROS",
     };
@@ -352,8 +353,9 @@
   SourceLocation MacroNameLoc = MacroNameTok.getLocation();
   if (ShadowFlag)
     *ShadowFlag = false;
-  if (!SourceMgr.isInSystemHeader(MacroNameLoc) &&
-      (SourceMgr.getBufferName(MacroNameLoc) != "<built-in>")) {
+  PresumedLoc PL = SourceMgr.getPresumedLoc(MacroNameLoc);
+  if (!SourceMgr.isInSystemHeader(MacroNameLoc) && PL.isValid() &&
+      strcmp(PL.getFilename(), "<built-in>")) {
     MacroDiag D = MD_NoWarn;
     if (isDefineUndef == MU_Define) {
       D = shouldWarnOnMacroDef(*this, II);