Support .code32 and .code64 in X86 assembler.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136197 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 9312a49..844793b 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -143,8 +143,9 @@
   // Do any generic stuff we need to do.
   switch (Flag) {
   case MCAF_SyntaxUnified: return; // no-op here.
-  case MCAF_Code16: return; // no-op here.
-  case MCAF_Code32: return; // no-op here.
+  case MCAF_Code16: return; // Change parsing mode; no-op here.
+  case MCAF_Code32: return; // Change parsing mode; no-op here.
+  case MCAF_Code64: return; // Change parsing mode; no-op here.
   case MCAF_SubsectionsViaSymbols:
     getAssembler().setSubsectionsViaSymbols(true);
     return;