--- a/include/llvm/Bitcode/BitCodes.h	Tue Jan 26 22:56:36 2016 +0900
+++ b/include/llvm/Bitcode/BitCodes.h	Fri Nov 25 19:14:25 2016 +0900
@@ -25,6 +25,14 @@
 #include <cassert>
 
 namespace llvm {
+/// Offsets of the 32-bit fields of bitcode wrapper header.
+static const unsigned BWH_MagicField = 0 * 4;
+static const unsigned BWH_VersionField = 1 * 4;
+static const unsigned BWH_OffsetField = 2 * 4;
+static const unsigned BWH_SizeField = 3 * 4;
+static const unsigned BWH_CPUTypeField = 4 * 4;
+static const unsigned BWH_HeaderSize = 5 * 4;
+
 namespace bitc {
   enum StandardWidths {
     BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
@@ -147,12 +155,8 @@
 
   static char DecodeChar6(unsigned V) {
     assert((V & ~63) == 0 && "Not a Char6 encoded character!");
-    if (V < 26)       return V+'a';
-    if (V < 26+26)    return V-26+'A';
-    if (V < 26+26+10) return V-26-26+'0';
-    if (V == 62)      return '.';
-    if (V == 63)      return '_';
-    llvm_unreachable("Not a value Char6 character!");
+    return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._"
+        [V];
   }
 
 };