2 files changed, 23 insertions, 1 deletions
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index e6e7ca5ee1..7983a6b3e8 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -2595,8 +2595,14 @@ LexNextToken:
       // Read the PP instance variable into an automatic variable, because
       // LexEndOfFile will often delete 'this'.
       Preprocessor *PPCache = PP;
+      bool EnableIncludedEOFCache = EnableIncludedEOF;
       if (LexEndOfFile(Result, CurPtr-1))  // Retreat back into the file.
         return;   // Got a token to return.
+
+      if (EnableIncludedEOFCache) {
+        Result.setKind(tok::included_eof);
+        return;
+      }
       assert(PPCache && "Raw buffer::LexEndOfFile should return a token");
       return PPCache->Lex(Result);
     }
@@ -3234,5 +3240,21 @@ HandleDirective:
     }
     goto LexNextToken;   // GCC isn't tail call eliminating.
   }
+
+  if (PreprocessorLexer *PPLex = PP->getCurrentLexer()) {
+    // If we #include something that contributes no tokens at all, return with
+    // a tok::included_eof instead of recursively continuing lexing.
+    // This avoids a stack overflow with a sequence of many empty #includes.
+    PPLex->setEnableIncludedEOF(true);
+    PP->Lex(Result);
+    if (Result.isNot(tok::included_eof)) {
+      if (Result.isNot(tok::eof) && Result.isNot(tok::eod))
+        PPLex->setEnableIncludedEOF(false);
+      return;
+    }
+    if (PP->isCurrentLexer(this))
+      goto LexNextToken;
+  }
+
   return PP->Lex(Result);
 }
diff --git a/lib/Lex/PreprocessorLexer.cpp b/lib/Lex/PreprocessorLexer.cpp
index a64c84d6bb..390d4c4523 100644
--- a/lib/Lex/PreprocessorLexer.cpp
+++ b/lib/Lex/PreprocessorLexer.cpp
@@ -22,7 +22,7 @@ void PreprocessorLexer::anchor() { }
 PreprocessorLexer::PreprocessorLexer(Preprocessor *pp, FileID fid)
   : PP(pp), FID(fid), InitialNumSLocEntries(0),
     ParsingPreprocessorDirective(false),
-    ParsingFilename(false), LexingRawMode(false) {
+    ParsingFilename(false), LexingRawMode(false), EnableIncludedEOF(false) {
   if (pp)
     InitialNumSLocEntries = pp->getSourceManager().local_sloc_entry_size();
 }