diff --git a/include/clang/Basic/TokenKinds.def b/include/clang/Basic/TokenKinds.def
index 704f1d9..25e8d5a 100644
--- a/include/clang/Basic/TokenKinds.def
+++ b/include/clang/Basic/TokenKinds.def
@@ -103,8 +103,6 @@
 TOK(eof)                 // End of file.
 TOK(eod)                 // End of preprocessing directive (end of line inside a
                          // directive).
-TOK(included_eof)        // End of included file, only if
-                         // PreprocessorLexer::EnableIncludedEOF is true.
 TOK(code_completion)     // Code completion marker
 TOK(cxx_defaultarg_end)  // C++ default argument end marker
 
diff --git a/include/clang/Lex/PreprocessorLexer.h b/include/clang/Lex/PreprocessorLexer.h
index b85729d..20fb8a0 100644
--- a/include/clang/Lex/PreprocessorLexer.h
+++ b/include/clang/Lex/PreprocessorLexer.h
@@ -61,10 +61,6 @@
   /// Note that in raw mode that the PP pointer may be null.
   bool LexingRawMode;
 
-  /// \brief When true, if EOF of the current lexer is found, tok::included_eof
-  /// is returned instead of continuing lexing higher in the include stack.
-  bool EnableIncludedEOF;
-
   /// \brief A state machine that detects the \#ifndef-wrapping a file
   /// idiom for the multiple-include optimization.
   MultipleIncludeOpt MIOpt;
@@ -83,8 +79,7 @@
     : PP(0), InitialNumSLocEntries(0),
       ParsingPreprocessorDirective(false),
       ParsingFilename(false),
-      LexingRawMode(false),
-      EnableIncludedEOF(false) {}
+      LexingRawMode(false) {}
 
   virtual ~PreprocessorLexer() {}
 
@@ -152,11 +147,6 @@
   /// \brief Return true if this lexer is in raw mode or not.
   bool isLexingRawMode() const { return LexingRawMode; }
 
-  /// \brief When true, if EOF of the current lexer is found, tok::included_eof
-  /// is returned instead of continuing lexing higher in the include stack.
-  /// False is the default behavior.
-  void setEnableIncludedEOF(bool Enable) { EnableIncludedEOF = Enable; }
-
   /// \brief Return the preprocessor object for this lexer.
   Preprocessor *getPP() const { return PP; }
 
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 6917645..bf0883e 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -2594,14 +2594,8 @@
       // 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);
     }
@@ -3239,21 +3233,5 @@
     }
     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 390d4c4..a64c84d 100644
--- a/lib/Lex/PreprocessorLexer.cpp
+++ b/lib/Lex/PreprocessorLexer.cpp
@@ -22,7 +22,7 @@
 PreprocessorLexer::PreprocessorLexer(Preprocessor *pp, FileID fid)
   : PP(pp), FID(fid), InitialNumSLocEntries(0),
     ParsingPreprocessorDirective(false),
-    ParsingFilename(false), LexingRawMode(false), EnableIncludedEOF(false) {
+    ParsingFilename(false), LexingRawMode(false) {
   if (pp)
     InitialNumSLocEntries = pp->getSourceManager().local_sloc_entry_size();
 }
diff --git a/test/Index/Inputs/empty.h b/test/Index/Inputs/empty.h
deleted file mode 100644
index e69de29..0000000
--- a/test/Index/Inputs/empty.h
+++ /dev/null
diff --git a/test/Index/pp-many-includes.c b/test/Index/pp-many-includes.c
deleted file mode 100644
index 8a53b4f..0000000
--- a/test/Index/pp-many-includes.c
+++ /dev/null
@@ -1,208 +0,0 @@
-// RUN: env LIBCLANG_THREAD_SMALLSTACK=1 c-index-test -index-file %s | FileCheck %s
-
-// rdar://11988695
-// Check that we don't get stack overflow while including a lot of empty includes.
-
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-#include "Inputs/empty.h"
-
-// CHECK: [indexDeclaration]: kind: function | name: foo
-void foo();
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index bb75db3..3a6c408 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -6119,8 +6119,6 @@
 bool RunSafely(llvm::CrashRecoveryContext &CRC,
                void (*Fn)(void*), void *UserData,
                unsigned Size) {
-  if (getenv("LIBCLANG_THREAD_SMALLSTACK"))
-    Size = 0x10000; // 64K.
   if (!Size)
     Size = GetSafetyThreadStackSize();
   if (Size)