diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index c192d28..5a92250 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -4511,7 +4511,7 @@
   QualType BlockTy =
       Expr->getType()->getAs<BlockPointerType>()->getPointeeType();
   // Encode result type.
-  if (getLangOpts().ObjCExtendedBlockEncode)
+  if (getLangOpts().EncodeExtendedBlockSig)
     getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None,
                             BlockTy->getAs<FunctionType>()->getResultType(),
                             S, true /*Extended*/);
@@ -4552,7 +4552,7 @@
         PType = PVDecl->getType();
     } else if (PType->isFunctionType())
       PType = PVDecl->getType();
-    if (getLangOpts().ObjCExtendedBlockEncode)
+    if (getLangOpts().EncodeExtendedBlockSig)
       getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, PType,
                                       S, true /*Extended*/);
     else
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index 8ea466a..2005d96 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -318,6 +318,10 @@
     return true;
   }
 
+  virtual bool IsEncodeExtendedBlockSignatureDefault() const {
+    return true;
+  }
+  
   virtual bool IsObjCNonFragileABIDefault() const {
     // Non-fragile ABI is default for everything but i386.
     return getTriple().getArch() != llvm::Triple::x86;
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index b1e450d..4dea717 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2727,6 +2727,11 @@
     CmdArgs.push_back("-fobjc-default-synthesize-properties");
   }
 
+  // -fencode-extended-block-signature=1 is default.
+  if (getToolChain().IsEncodeExtendedBlockSignatureDefault()) {
+    CmdArgs.push_back("-fencode-extended-block-signature");
+  }
+  
   // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
   // NOTE: This logic is duplicated in ToolChains.cpp.
   bool ARC = isObjCAutoRefCount(Args);
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index df4c883..2e8ae63 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1126,8 +1126,6 @@
 
   if (Args.hasArg(OPT_print_ivar_layout))
     Opts.ObjCGCBitmapPrint = 1;
-  if (Args.hasArg(OPT_encode_extended_block_sig))
-    Opts.ObjCExtendedBlockEncode = 1;
   if (Args.hasArg(OPT_fno_constant_cfstrings))
     Opts.NoConstantCFStrings = 1;
 
@@ -1216,6 +1214,8 @@
     Args.getLastArgValue(OPT_fconstant_string_class);
   Opts.ObjCDefaultSynthProperties =
     Args.hasArg(OPT_fobjc_default_synthesize_properties);
+  Opts.EncodeExtendedBlockSig =
+    Args.hasArg(OPT_fencode_extended_block_signature);
   Opts.EmitAllDecls = Args.hasArg(OPT_femit_all_decls);
   Opts.PackStruct = Args.getLastArgIntValue(OPT_fpack_struct_EQ, 0, Diags);
   Opts.PICLevel = Args.getLastArgIntValue(OPT_pic_level, 0, Diags);