Implement visibility checking during linking. Also implement protected

visibility support for bitcode.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36577 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -59,6 +59,7 @@ static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
   default: // Map unknown visibilities to default.
   case 0: return GlobalValue::DefaultVisibility;
   case 1: return GlobalValue::HiddenVisibility;
+  case 2: return GlobalValue::ProtectedVisibility;
   }
 }