Add (unsupported experimental) feature allowing byte aligned bitcode.

lib/Bitcode/NaCl/Analysis/NaClObjDump.cpp

 //===-- NaClObjDump.cpp - Dump PNaCl bitcode contents ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/STLExtras.h"
@@ skipping 3513 matching lines @@
   naclbitc::ObjDumpStream ObjDump(Output, !NoRecords, !NoAssembly);
 
   if (MemBuf.getBufferSize() % 4 != 0) {
     ObjDump.Error()
         << "Bitcode stream should be a multiple of 4 bytes in length.\n";
     return true;
   }
 
   const unsigned char *BufPtr = (const unsigned char *)MemBuf.getBufferStart();
   const unsigned char *EndBufPtr = BufPtr+MemBuf.getBufferSize();
-  const unsigned char *HeaderPtr = BufPtr;
 
   // Read header and verify it is good.
   NaClBitcodeHeader Header;
-  if (Header.Read(HeaderPtr, EndBufPtr) || !Header.IsSupported()) {
+  if (Header.Read(BufPtr, EndBufPtr)) {
     ObjDump.Error() << "Invalid PNaCl bitcode header.\n";
     return true;
   }
+  if (!Header.IsSupported()) {
+    ObjDump.Warning() << Header.Unsupported();
+    if (!Header.IsReadable()) {
+      ObjDump.Error() << "Invalid PNaCl bitcode header.\n";
+      return true;
+    }
+  }
 
   // Create a bitstream reader to read the bitcode file.
-  NaClBitstreamReader InputStreamFile(BufPtr, EndBufPtr,
-                                      Header.getHeaderSize());
+  NaClBitstreamReader InputStreamFile(BufPtr, EndBufPtr, Header);
   NaClBitstreamCursor InputStream(InputStreamFile);
 
   // Parse the the bitcode file.
   ::NaClDisTopLevelParser Parser(Header, InputStream, ObjDump);
   int NumBlocksRead = 0;
   bool ErrorsFound = false;
   while (!InputStream.AtEndOfStream()) {
     ++NumBlocksRead;
     if (Parser.Parse()) ErrorsFound = true;
   }
 
   if (NumBlocksRead != 1) {
     ObjDump.Error() << "Expected 1 top level block in bitcode: Found:"
                     << NumBlocksRead << "\n";
     ErrorsFound = true;
   }
 
   ObjDump.Flush();
   return ErrorsFound || Parser.GetNumErrors() > 0;
 }
 
 }