Add (unsupported experimental) feature allowing byte aligned bitcode.

lib/Bitcode/NaCl/TestUtils/NaClBitcodeMungeReader.cpp

 //===- NaClBitcodeMungeReader.cpp - Read bitcode record list ----*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Implements bitcode reader for NaClBitcodeRecordList and NaClMungedBitcode.
@@ skipping 113 matching lines @@
 void llvm::readNaClBitcodeRecordList(
     NaClBitcodeRecordList &RecordList,
     std::unique_ptr<MemoryBuffer> InputBuffer) {
   if (InputBuffer->getBufferSize() % 4 != 0)
     report_fatal_error(
         "Bitcode stream must be a multiple of 4 bytes in length");
 
   const unsigned char *BufPtr =
       (const unsigned char *) InputBuffer->getBufferStart();
   const unsigned char *EndBufPtr = BufPtr + InputBuffer->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))
+    report_fatal_error("Invalid PNaCl bitcode header.\n");
+  if (!Header.IsSupported())
+    errs() << Header.Unsupported();
+  if (!Header.IsReadable())
     report_fatal_error("Invalid PNaCl bitcode header.\n");
 
-  NaClBitstreamReader Reader(BufPtr, EndBufPtr, Header.getHeaderSize());
+  NaClBitstreamReader Reader(BufPtr, EndBufPtr, Header);
   NaClBitstreamCursor Cursor(Reader);
 
   // Parse the bitcode buffer.
   BitcodeParser Parser(Cursor, RecordList);
 
   while (!Cursor.AtEndOfStream()) {
     if (Parser.Parse())
       report_fatal_error("Malformed records founds, unable to continue");
   }
 }
 
 
 NaClMungedBitcode::NaClMungedBitcode(std::unique_ptr<MemoryBuffer> InputBuffer)
     : BaseRecords(new NaClBitcodeRecordList()) {
   readNaClBitcodeRecordList(*BaseRecords, std::move(InputBuffer));
 }