Copy LLVM bitcode reader to generate a PNaCl wire format reader.

Copy classes for LLVM BitcodeReader into a NaCl subdirectory, to create a wire
format version. Renames classes/functions to include NaCl prefix, so that
they don't conflict with the LLVM Bitcode reader.

Also implements pnacl-thaw, showing that we can read the PNaCl wire format
files.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3405
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/14314016

19 files changed, 5248 insertions, 205 deletions

diff --git a/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h b/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
new file mode 100644
index 0000000000..238ce5275a
--- /dev/null
+++ b/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
@@ -0,0 +1,560 @@
+//===- NaClBitstreamReader.h -----------------------------------*- C++ -*-===//
+//     Low-level bitstream reader interface
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines the BitstreamReader class.  This class can be used to
+// read an arbitrary bitstream, regardless of its contents.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITCODE_NACL_NACLBITSTREAMREADER_H
+#define LLVM_BITCODE_NACL_NACLBITSTREAMREADER_H
+
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Bitcode/NaCl/NaClLLVMBitCodes.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/StreamableMemoryObject.h"
+#include <climits>
+#include <string>
+#include <vector>
+
+namespace llvm {
+
+  class Deserializer;
+
+/// NaClBitstreamReader - This class is used to read from a NaCl
+/// bitcode wire format stream, maintaining information that is global
+/// to decoding the entire file.  While a file is being read, multiple
+/// cursors can be independently advanced or skipped around within the
+/// file.  These are represented by the NaClBitstreamCursor class.
+class NaClBitstreamReader {
+public:
+  /// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks.
+  /// These describe abbreviations that all blocks of the specified ID inherit.
+  struct BlockInfo {
+    unsigned BlockID;
+    std::vector<BitCodeAbbrev*> Abbrevs;
+    std::string Name;
+
+    std::vector<std::pair<unsigned, std::string> > RecordNames;
+  };
+private:
+  OwningPtr<StreamableMemoryObject> BitcodeBytes;
+
+  std::vector<BlockInfo> BlockInfoRecords;
+
+  /// IgnoreBlockInfoNames - This is set to true if we don't care about the
+  /// block/record name information in the BlockInfo block. Only llvm-bcanalyzer
+  /// uses this.
+  bool IgnoreBlockInfoNames;
+
+  NaClBitstreamReader(const NaClBitstreamReader&) LLVM_DELETED_FUNCTION;
+  void operator=(const NaClBitstreamReader&) LLVM_DELETED_FUNCTION;
+public:
+  NaClBitstreamReader() : IgnoreBlockInfoNames(true) {
+  }
+
+  NaClBitstreamReader(const unsigned char *Start, const unsigned char *End) {
+    IgnoreBlockInfoNames = true;
+    init(Start, End);
+  }
+
+  NaClBitstreamReader(StreamableMemoryObject *bytes) {
+    BitcodeBytes.reset(bytes);
+  }
+
+  void init(const unsigned char *Start, const unsigned char *End) {
+    assert(((End-Start) & 3) == 0 &&"Bitcode stream not a multiple of 4 bytes");
+    BitcodeBytes.reset(getNonStreamedMemoryObject(Start, End));
+  }
+
+  StreamableMemoryObject &getBitcodeBytes() { return *BitcodeBytes; }
+
+  ~NaClBitstreamReader() {
+    // Free the BlockInfoRecords.
+    while (!BlockInfoRecords.empty()) {
+      BlockInfo &Info = BlockInfoRecords.back();
+      // Free blockinfo abbrev info.
+      for (unsigned i = 0, e = static_cast<unsigned>(Info.Abbrevs.size());
+           i != e; ++i)
+        Info.Abbrevs[i]->dropRef();
+      BlockInfoRecords.pop_back();
+    }
+  }
+
+  /// CollectBlockInfoNames - This is called by clients that want block/record
+  /// name information.
+  void CollectBlockInfoNames() { IgnoreBlockInfoNames = false; }
+  bool isIgnoringBlockInfoNames() { return IgnoreBlockInfoNames; }
+
+  //===--------------------------------------------------------------------===//
+  // Block Manipulation
+  //===--------------------------------------------------------------------===//
+
+  /// hasBlockInfoRecords - Return true if we've already read and processed the
+  /// block info block for this Bitstream.  We only process it for the first
+  /// cursor that walks over it.
+  bool hasBlockInfoRecords() const { return !BlockInfoRecords.empty(); }
+
+  /// getBlockInfo - If there is block info for the specified ID, return it,
+  /// otherwise return null.
+  const BlockInfo *getBlockInfo(unsigned BlockID) const {
+    // Common case, the most recent entry matches BlockID.
+    if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
+      return &BlockInfoRecords.back();
+
+    for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
+         i != e; ++i)
+      if (BlockInfoRecords[i].BlockID == BlockID)
+        return &BlockInfoRecords[i];
+    return 0;
+  }
+
+  BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
+    if (const BlockInfo *BI = getBlockInfo(BlockID))
+      return *const_cast<BlockInfo*>(BI);
+
+    // Otherwise, add a new record.
+    BlockInfoRecords.push_back(BlockInfo());
+    BlockInfoRecords.back().BlockID = BlockID;
+    return BlockInfoRecords.back();
+  }
+};
+
+  
+/// NaClBitstreamEntry - When advancing through a bitstream cursor,
+/// each advance can discover a few different kinds of entries:
+///   Error    - Malformed bitcode was found.
+///   EndBlock - We've reached the end of the current block, (or the end of the
+///              file, which is treated like a series of EndBlock records.
+///   SubBlock - This is the start of a new subblock of a specific ID.
+///   Record   - This is a record with a specific AbbrevID.
+///
+struct NaClBitstreamEntry {
+  enum {
+    Error,
+    EndBlock,
+    SubBlock,
+    Record
+  } Kind;
+  
+  unsigned ID;
+
+  static NaClBitstreamEntry getError() {
+    NaClBitstreamEntry E; E.Kind = Error; return E;
+  }
+  static NaClBitstreamEntry getEndBlock() {
+    NaClBitstreamEntry E; E.Kind = EndBlock; return E;
+  }
+  static NaClBitstreamEntry getSubBlock(unsigned ID) {
+    NaClBitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
+  }
+  static NaClBitstreamEntry getRecord(unsigned AbbrevID) {
+    NaClBitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
+  }
+};
+
+/// NaClBitstreamCursor - This represents a position within a bitcode
+/// file.  There may be multiple independent cursors reading within
+/// one bitstream, each maintaining their own local state.
+///
+/// Unlike iterators, NaClBitstreamCursors are heavy-weight objects
+/// that should not be passed by value.
+class NaClBitstreamCursor {
+  friend class Deserializer;
+  NaClBitstreamReader *BitStream;
+  size_t NextChar;
+
+  
+  /// CurWord/word_t - This is the current data we have pulled from the stream
+  /// but have not returned to the client.  This is specifically and
+  /// intentionally defined to follow the word size of the host machine for
+  /// efficiency.  We use word_t in places that are aware of this to make it
+  /// perfectly explicit what is going on.
+  typedef uint32_t word_t;
+  word_t CurWord;
+
+  /// BitsInCurWord - This is the number of bits in CurWord that are valid. This
+  /// is always from [0...31/63] inclusive (depending on word size).
+  unsigned BitsInCurWord;
+
+  // CurCodeSize - This is the declared size of code values used for the current
+  // block, in bits.
+  unsigned CurCodeSize;
+
+  /// CurAbbrevs - Abbrevs installed at in this block.
+  std::vector<BitCodeAbbrev*> CurAbbrevs;
+
+  struct Block {
+    unsigned PrevCodeSize;
+    std::vector<BitCodeAbbrev*> PrevAbbrevs;
+    explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
+  };
+
+  /// BlockScope - This tracks the codesize of parent blocks.
+  SmallVector<Block, 8> BlockScope;
+
+  
+public:
+  NaClBitstreamCursor() : BitStream(0), NextChar(0) {
+  }
+  NaClBitstreamCursor(const NaClBitstreamCursor &RHS)
+      : BitStream(0), NextChar(0) {
+    operator=(RHS);
+  }
+
+  explicit NaClBitstreamCursor(NaClBitstreamReader &R) : BitStream(&R) {
+    NextChar = 0;
+    CurWord = 0;
+    BitsInCurWord = 0;
+    CurCodeSize = 2;
+  }
+
+  void init(NaClBitstreamReader &R) {
+    freeState();
+
+    BitStream = &R;
+    NextChar = 0;
+    CurWord = 0;
+    BitsInCurWord = 0;
+    CurCodeSize = 2;
+  }
+
+  ~NaClBitstreamCursor() {
+    freeState();
+  }
+
+  void operator=(const NaClBitstreamCursor &RHS);
+
+  void freeState();
+  
+  bool isEndPos(size_t pos) {
+    return BitStream->getBitcodeBytes().isObjectEnd(static_cast<uint64_t>(pos));
+  }
+
+  bool canSkipToPos(size_t pos) const {
+    // pos can be skipped to if it is a valid address or one byte past the end.
+    return pos == 0 || BitStream->getBitcodeBytes().isValidAddress(
+        static_cast<uint64_t>(pos - 1));
+  }
+
+  uint32_t getWord(size_t pos) {
+    uint8_t buf[4] = { 0xFF, 0xFF, 0xFF, 0xFF };
+    BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf, NULL);
+    return *reinterpret_cast<support::ulittle32_t *>(buf);
+  }
+
+  bool AtEndOfStream() {
+    return BitsInCurWord == 0 && isEndPos(NextChar);
+  }
+
+  /// getAbbrevIDWidth - Return the number of bits used to encode an abbrev #.
+  unsigned getAbbrevIDWidth() const { return CurCodeSize; }
+
+  /// GetCurrentBitNo - Return the bit # of the bit we are reading.
+  uint64_t GetCurrentBitNo() const {
+    return NextChar*CHAR_BIT - BitsInCurWord;
+  }
+
+  NaClBitstreamReader *getBitStreamReader() {
+    return BitStream;
+  }
+  const NaClBitstreamReader *getBitStreamReader() const {
+    return BitStream;
+  }
+
+  /// Flags that modify the behavior of advance().
+  enum {
+    /// AF_DontPopBlockAtEnd - If this flag is used, the advance() method does
+    /// not automatically pop the block scope when the end of a block is
+    /// reached.
+    AF_DontPopBlockAtEnd = 1,
+
+    /// AF_DontAutoprocessAbbrevs - If this flag is used, abbrev entries are
+    /// returned just like normal records.
+    AF_DontAutoprocessAbbrevs = 2
+  };
+  
+  /// advance - Advance the current bitstream, returning the next entry in the
+  /// stream.
+  NaClBitstreamEntry advance(unsigned Flags = 0) {
+    while (1) {
+      unsigned Code = ReadCode();
+      if (Code == bitc::END_BLOCK) {
+        // Pop the end of the block unless Flags tells us not to.
+        if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
+          return NaClBitstreamEntry::getError();
+        return NaClBitstreamEntry::getEndBlock();
+      }
+      
+      if (Code == bitc::ENTER_SUBBLOCK)
+        return NaClBitstreamEntry::getSubBlock(ReadSubBlockID());
+      
+      if (Code == bitc::DEFINE_ABBREV &&
+          !(Flags & AF_DontAutoprocessAbbrevs)) {
+        // We read and accumulate abbrev's, the client can't do anything with
+        // them anyway.
+        ReadAbbrevRecord();
+        continue;
+      }
+
+      return NaClBitstreamEntry::getRecord(Code);
+    }
+  }
+
+  /// advanceSkippingSubblocks - This is a convenience function for clients that
+  /// don't expect any subblocks.  This just skips over them automatically.
+  NaClBitstreamEntry advanceSkippingSubblocks(unsigned Flags = 0) {
+    while (1) {
+      // If we found a normal entry, return it.
+      NaClBitstreamEntry Entry = advance(Flags);
+      if (Entry.Kind != NaClBitstreamEntry::SubBlock)
+        return Entry;
+      
+      // If we found a sub-block, just skip over it and check the next entry.
+      if (SkipBlock())
+        return NaClBitstreamEntry::getError();
+    }
+  }
+
+  /// JumpToBit - Reset the stream to the specified bit number.
+  void JumpToBit(uint64_t BitNo) {
+    uintptr_t ByteNo = uintptr_t(BitNo/8) & ~(sizeof(word_t)-1);
+    unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
+    assert(canSkipToPos(ByteNo) && "Invalid location");
+
+    // Move the cursor to the right word.
+    NextChar = ByteNo;
+    BitsInCurWord = 0;
+    CurWord = 0;
+
+    // Skip over any bits that are already consumed.
+    if (WordBitNo) {
+      if (sizeof(word_t) > 4)
+        Read64(WordBitNo);
+      else
+        Read(WordBitNo);
+    }
+  }
+
+
+  uint32_t Read(unsigned NumBits) {
+    assert(NumBits && NumBits <= 32 &&
+           "Cannot return zero or more than 32 bits!");
+    
+    // If the field is fully contained by CurWord, return it quickly.
+    if (BitsInCurWord >= NumBits) {
+      uint32_t R = uint32_t(CurWord) & (~0U >> (32-NumBits));
+      CurWord >>= NumBits;
+      BitsInCurWord -= NumBits;
+      return R;
+    }
+
+    // If we run out of data, stop at the end of the stream.
+    if (isEndPos(NextChar)) {
+      CurWord = 0;
+      BitsInCurWord = 0;
+      return 0;
+    }
+
+    uint32_t R = uint32_t(CurWord);
+
+    // Read the next word from the stream.
+    uint8_t Array[sizeof(word_t)] = {0};
+    
+    BitStream->getBitcodeBytes().readBytes(NextChar, sizeof(Array),
+                                           Array, NULL);
+    
+    // Handle big-endian byte-swapping if necessary.
+    support::detail::packed_endian_specific_integral
+      <word_t, support::little, support::unaligned> EndianValue;
+    memcpy(&EndianValue, Array, sizeof(Array));
+    
+    CurWord = EndianValue;
+
+    NextChar += sizeof(word_t);
+
+    // Extract NumBits-BitsInCurWord from what we just read.
+    unsigned BitsLeft = NumBits-BitsInCurWord;
+
+    // Be careful here, BitsLeft is in the range [1..32]/[1..64] inclusive.
+    R |= uint32_t((CurWord & (word_t(~0ULL) >> (sizeof(word_t)*8-BitsLeft)))
+                    << BitsInCurWord);
+
+    // BitsLeft bits have just been used up from CurWord.  BitsLeft is in the
+    // range [1..32]/[1..64] so be careful how we shift.
+    if (BitsLeft != sizeof(word_t)*8)
+      CurWord >>= BitsLeft;
+    else
+      CurWord = 0;
+    BitsInCurWord = sizeof(word_t)*8-BitsLeft;
+    return R;
+  }
+
+  uint64_t Read64(unsigned NumBits) {
+    if (NumBits <= 32) return Read(NumBits);
+
+    uint64_t V = Read(32);
+    return V | (uint64_t)Read(NumBits-32) << 32;
+  }
+
+  uint32_t ReadVBR(unsigned NumBits) {
+    uint32_t Piece = Read(NumBits);
+    if ((Piece & (1U << (NumBits-1))) == 0)
+      return Piece;
+
+    uint32_t Result = 0;
+    unsigned NextBit = 0;
+    while (1) {
+      Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
+
+      if ((Piece & (1U << (NumBits-1))) == 0)
+        return Result;
+
+      NextBit += NumBits-1;
+      Piece = Read(NumBits);
+    }
+  }
+
+  // ReadVBR64 - Read a VBR that may have a value up to 64-bits in size.  The
+  // chunk size of the VBR must still be <= 32 bits though.
+  uint64_t ReadVBR64(unsigned NumBits) {
+    uint32_t Piece = Read(NumBits);
+    if ((Piece & (1U << (NumBits-1))) == 0)
+      return uint64_t(Piece);
+
+    uint64_t Result = 0;
+    unsigned NextBit = 0;
+    while (1) {
+      Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
+
+      if ((Piece & (1U << (NumBits-1))) == 0)
+        return Result;
+
+      NextBit += NumBits-1;
+      Piece = Read(NumBits);
+    }
+  }
+
+private:
+  void SkipToFourByteBoundary() {
+    // If word_t is 64-bits and if we've read less than 32 bits, just dump
+    // the bits we have up to the next 32-bit boundary.
+    if (sizeof(word_t) > 4 &&
+        BitsInCurWord >= 32) {
+      CurWord >>= BitsInCurWord-32;
+      BitsInCurWord = 32;
+      return;
+    }
+    
+    BitsInCurWord = 0;
+    CurWord = 0;
+  }
+public:
+
+  unsigned ReadCode() {
+    return Read(CurCodeSize);
+  }
+
+
+  // Block header:
+  //    [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
+
+  /// ReadSubBlockID - Having read the ENTER_SUBBLOCK code, read the BlockID for
+  /// the block.
+  unsigned ReadSubBlockID() {
+    return ReadVBR(bitc::BlockIDWidth);
+  }
+
+  /// SkipBlock - Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip
+  /// over the body of this block.  If the block record is malformed, return
+  /// true.
+  bool SkipBlock() {
+    // Read and ignore the codelen value.  Since we are skipping this block, we
+    // don't care what code widths are used inside of it.
+    ReadVBR(bitc::CodeLenWidth);
+    SkipToFourByteBoundary();
+    unsigned NumFourBytes = Read(bitc::BlockSizeWidth);
+
+    // Check that the block wasn't partially defined, and that the offset isn't
+    // bogus.
+    size_t SkipTo = GetCurrentBitNo() + NumFourBytes*4*8;
+    if (AtEndOfStream() || !canSkipToPos(SkipTo/8))
+      return true;
+
+    JumpToBit(SkipTo);
+    return false;
+  }
+
+  /// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
+  /// the block, and return true if the block has an error.
+  bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = 0);
+  
+  bool ReadBlockEnd() {
+    if (BlockScope.empty()) return true;
+
+    // Block tail:
+    //    [END_BLOCK, <align4bytes>]
+    SkipToFourByteBoundary();
+
+    popBlockScope();
+    return false;
+  }
+
+private:
+
+  void popBlockScope() {
+    CurCodeSize = BlockScope.back().PrevCodeSize;
+
+    // Delete abbrevs from popped scope.
+    for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
+         i != e; ++i)
+      CurAbbrevs[i]->dropRef();
+
+    BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+    BlockScope.pop_back();
+  }
+
+  //===--------------------------------------------------------------------===//
+  // Record Processing
+  //===--------------------------------------------------------------------===//
+
+private:
+  void readAbbreviatedLiteral(const BitCodeAbbrevOp &Op,
+                              SmallVectorImpl<uint64_t> &Vals);
+  void readAbbreviatedField(const BitCodeAbbrevOp &Op,
+                            SmallVectorImpl<uint64_t> &Vals);
+  void skipAbbreviatedField(const BitCodeAbbrevOp &Op);
+  
+public:
+
+  /// getAbbrev - Return the abbreviation for the specified AbbrevId.
+  const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
+    unsigned AbbrevNo = AbbrevID-bitc::FIRST_APPLICATION_ABBREV;
+    assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
+    return CurAbbrevs[AbbrevNo];
+  }
+
+  /// skipRecord - Read the current record and discard it.
+  void skipRecord(unsigned AbbrevID);
+  
+  unsigned readRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
+                      StringRef *Blob = 0);
+
+  //===--------------------------------------------------------------------===//
+  // Abbrev Processing
+  //===--------------------------------------------------------------------===//
+  void ReadAbbrevRecord();
+  
+  bool ReadBlockInfoBlock();
+};
+
+} // End llvm namespace
+
+#endif
diff --git a/include/llvm/Bitcode/NaCl/NaClLLVMBitCodes.h b/include/llvm/Bitcode/NaCl/NaClLLVMBitCodes.h
new file mode 100644
index 0000000000..a211a61edc
--- /dev/null
+++ b/include/llvm/Bitcode/NaCl/NaClLLVMBitCodes.h
@@ -0,0 +1,339 @@
+//===- NaClLLVMBitCodes.h ---------------------------------------*- C++ -*-===//
+//     Enum values for the NaCl bitcode wire format
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines Bitcode enum values for NaCl bitcode wire format.
+//
+// The enum values defined in this file should be considered permanent.  If
+// new features are added, they should have values added at the end of the
+// respective lists.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITCODE_NACL_NACLBITCODES_H
+#define LLVM_BITCODE_NACL_NACLBITCODES_H
+
+// TODO(kschimpf) Make a NaCl version of BitCodes.h, so that block id's
+// and abbreviations can be modified.
+#include "llvm/Bitcode/BitCodes.h"
+
+namespace llvm {
+namespace naclbitc {
+  // The only top-level block type defined is for a module.
+  enum NaClBlockIDs {
+    // Blocks
+    MODULE_BLOCK_ID          = bitc::FIRST_APPLICATION_BLOCKID,
+
+    // Module sub-block id's.
+    PARAMATTR_BLOCK_ID,
+    PARAMATTR_GROUP_BLOCK_ID,
+
+    CONSTANTS_BLOCK_ID,
+    FUNCTION_BLOCK_ID,
+
+    UNUSED_ID1,
+
+    VALUE_SYMTAB_BLOCK_ID,
+    METADATA_BLOCK_ID,
+    METADATA_ATTACHMENT_ID,
+
+    TYPE_BLOCK_ID_NEW,
+
+    USELIST_BLOCK_ID
+  };
+
+
+  /// MODULE blocks have a number of optional fields and subblocks.
+  enum NaClModuleCodes {
+    MODULE_CODE_VERSION     = 1,    // VERSION:     [version#]
+    MODULE_CODE_TRIPLE      = 2,    // TRIPLE:      [strchr x N]
+    MODULE_CODE_DATALAYOUT  = 3,    // DATALAYOUT:  [strchr x N]
+    MODULE_CODE_ASM         = 4,    // ASM:         [strchr x N]
+    MODULE_CODE_SECTIONNAME = 5,    // SECTIONNAME: [strchr x N]
+
+    // FIXME: Remove DEPLIB in 4.0.
+    MODULE_CODE_DEPLIB      = 6,    // DEPLIB:      [strchr x N]
+
+    // GLOBALVAR: [pointer type, isconst, initid,
+    //             linkage, alignment, section, visibility, threadlocal]
+    MODULE_CODE_GLOBALVAR   = 7,
+
+    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
+    //             section, visibility, gc, unnamed_addr]
+    MODULE_CODE_FUNCTION    = 8,
+
+    // ALIAS: [alias type, aliasee val#, linkage, visibility]
+    MODULE_CODE_ALIAS       = 9,
+
+    // MODULE_CODE_PURGEVALS: [numvals]
+    MODULE_CODE_PURGEVALS   = 10,
+
+    MODULE_CODE_GCNAME      = 11   // GCNAME: [strchr x N]
+  };
+
+  /// PARAMATTR blocks have code for defining a parameter attribute set.
+  enum NaClAttributeCodes {
+    // FIXME: Remove `PARAMATTR_CODE_ENTRY_OLD' in 4.0
+    PARAMATTR_CODE_ENTRY_OLD  = 1, // ENTRY: [paramidx0, attr0,
+                                   //         paramidx1, attr1...]
+    PARAMATTR_CODE_ENTRY      = 2, // ENTRY: [paramidx0, attrgrp0,
+                                   //         paramidx1, attrgrp1, ...]
+    PARAMATTR_GRP_CODE_ENTRY  = 3  // ENTRY: [id, attr0, att1, ...]
+  };
+
+  /// TYPE blocks have codes for each type primitive they use.
+  enum NaClTypeCodes {
+    TYPE_CODE_NUMENTRY =  1,    // NUMENTRY: [numentries]
+
+    // Type Codes
+    TYPE_CODE_VOID     =  2,    // VOID
+    TYPE_CODE_FLOAT    =  3,    // FLOAT
+    TYPE_CODE_DOUBLE   =  4,    // DOUBLE
+    TYPE_CODE_LABEL    =  5,    // LABEL
+    TYPE_CODE_OPAQUE   =  6,    // OPAQUE
+    TYPE_CODE_INTEGER  =  7,    // INTEGER: [width]
+    TYPE_CODE_POINTER  =  8,    // POINTER: [pointee type]
+
+    TYPE_CODE_FUNCTION_OLD = 9, // FUNCTION: [vararg, attrid, retty,
+                                //            paramty x N]
+
+    TYPE_CODE_HALF     =  10,   // HALF
+
+    TYPE_CODE_ARRAY    = 11,    // ARRAY: [numelts, eltty]
+    TYPE_CODE_VECTOR   = 12,    // VECTOR: [numelts, eltty]
+
+    // These are not with the other floating point types because they're
+    // a late addition, and putting them in the right place breaks
+    // binary compatibility.
+    TYPE_CODE_X86_FP80 = 13,    // X86 LONG DOUBLE
+    TYPE_CODE_FP128    = 14,    // LONG DOUBLE (112 bit mantissa)
+    TYPE_CODE_PPC_FP128= 15,    // PPC LONG DOUBLE (2 doubles)
+
+    TYPE_CODE_METADATA = 16,    // METADATA
+
+    TYPE_CODE_X86_MMX = 17,     // X86 MMX
+
+    TYPE_CODE_STRUCT_ANON = 18, // STRUCT_ANON: [ispacked, eltty x N]
+    TYPE_CODE_STRUCT_NAME = 19, // STRUCT_NAME: [strchr x N]
+    TYPE_CODE_STRUCT_NAMED = 20,// STRUCT_NAMED: [ispacked, eltty x N]
+
+    TYPE_CODE_FUNCTION = 21     // FUNCTION: [vararg, retty, paramty x N]
+  };
+
+  // The type symbol table only has one code (TST_ENTRY_CODE).
+  enum NaClTypeSymtabCodes {
+    TST_CODE_ENTRY = 1     // TST_ENTRY: [typeid, namechar x N]
+  };
+
+  // The value symbol table only has one code (VST_ENTRY_CODE).
+  enum NaClValueSymtabCodes {
+    VST_CODE_ENTRY   = 1,  // VST_ENTRY: [valid, namechar x N]
+    VST_CODE_BBENTRY = 2   // VST_BBENTRY: [bbid, namechar x N]
+  };
+
+  enum NaClMetadataCodes {
+    METADATA_STRING        = 1,   // MDSTRING:      [values]
+    // 2 is unused.
+    // 3 is unused.
+    METADATA_NAME          = 4,   // STRING:        [values]
+    // 5 is unused.
+    METADATA_KIND          = 6,   // [n x [id, name]]
+    // 7 is unused.
+    METADATA_NODE          = 8,   // NODE:          [n x (type num, value num)]
+    METADATA_FN_NODE       = 9,   // FN_NODE:       [n x (type num, value num)]
+    METADATA_NAMED_NODE    = 10,  // NAMED_NODE:    [n x mdnodes]
+    METADATA_ATTACHMENT    = 11   // [m x [value, [n x [id, mdnode]]]
+  };
+
+  // The constants block (CONSTANTS_BLOCK_ID) describes emission for each
+  // constant and maintains an implicit current type value.
+  enum NaClConstantsCodes {
+    CST_CODE_SETTYPE       =  1,  // SETTYPE:       [typeid]
+    CST_CODE_NULL          =  2,  // NULL
+    CST_CODE_UNDEF         =  3,  // UNDEF
+    CST_CODE_INTEGER       =  4,  // INTEGER:       [intval]
+    CST_CODE_WIDE_INTEGER  =  5,  // WIDE_INTEGER:  [n x intval]
+    CST_CODE_FLOAT         =  6,  // FLOAT:         [fpval]
+    CST_CODE_AGGREGATE     =  7,  // AGGREGATE:     [n x value number]
+    CST_CODE_STRING        =  8,  // STRING:        [values]
+    CST_CODE_CSTRING       =  9,  // CSTRING:       [values]
+    CST_CODE_CE_BINOP      = 10,  // CE_BINOP:      [opcode, opval, opval]
+    CST_CODE_CE_CAST       = 11,  // CE_CAST:       [opcode, opty, opval]
+    CST_CODE_CE_GEP        = 12,  // CE_GEP:        [n x operands]
+    CST_CODE_CE_SELECT     = 13,  // CE_SELECT:     [opval, opval, opval]
+    CST_CODE_CE_EXTRACTELT = 14,  // CE_EXTRACTELT: [opty, opval, opval]
+    CST_CODE_CE_INSERTELT  = 15,  // CE_INSERTELT:  [opval, opval, opval]
+    CST_CODE_CE_SHUFFLEVEC = 16,  // CE_SHUFFLEVEC: [opval, opval, opval]
+    CST_CODE_CE_CMP        = 17,  // CE_CMP:        [opty, opval, opval, pred]
+    CST_CODE_INLINEASM_OLD = 18,  // INLINEASM:     [sideeffect|alignstack,
+                                  //                 asmstr,conststr]
+    CST_CODE_CE_SHUFVEC_EX = 19,  // SHUFVEC_EX:    [opty, opval, opval, opval]
+    CST_CODE_CE_INBOUNDS_GEP = 20,// INBOUNDS_GEP:  [n x operands]
+    CST_CODE_BLOCKADDRESS  = 21,  // CST_CODE_BLOCKADDRESS [fnty, fnval, bb#]
+    CST_CODE_DATA          = 22,  // DATA:          [n x elements]
+    CST_CODE_INLINEASM     = 23   // INLINEASM:     [sideeffect|alignstack|
+                                  //                 asmdialect,asmstr,conststr]
+  };
+
+  /// CastOpcodes - These are values used in the bitcode files to encode which
+  /// cast a CST_CODE_CE_CAST or a XXX refers to.  The values of these enums
+  /// have no fixed relation to the LLVM IR enum values.  Changing these will
+  /// break compatibility with old files.
+  enum NaClCastOpcodes {
+    CAST_TRUNC    =  0,
+    CAST_ZEXT     =  1,
+    CAST_SEXT     =  2,
+    CAST_FPTOUI   =  3,
+    CAST_FPTOSI   =  4,
+    CAST_UITOFP   =  5,
+    CAST_SITOFP   =  6,
+    CAST_FPTRUNC  =  7,
+    CAST_FPEXT    =  8,
+    CAST_PTRTOINT =  9,
+    CAST_INTTOPTR = 10,
+    CAST_BITCAST  = 11
+  };
+
+  /// BinaryOpcodes - These are values used in the bitcode files to encode which
+  /// binop a CST_CODE_CE_BINOP or a XXX refers to.  The values of these enums
+  /// have no fixed relation to the LLVM IR enum values.  Changing these will
+  /// break compatibility with old files.
+  enum NaClBinaryOpcodes {
+    BINOP_ADD  =  0,
+    BINOP_SUB  =  1,
+    BINOP_MUL  =  2,
+    BINOP_UDIV =  3,
+    BINOP_SDIV =  4,    // overloaded for FP
+    BINOP_UREM =  5,
+    BINOP_SREM =  6,    // overloaded for FP
+    BINOP_SHL  =  7,
+    BINOP_LSHR =  8,
+    BINOP_ASHR =  9,
+    BINOP_AND  = 10,
+    BINOP_OR   = 11,
+    BINOP_XOR  = 12
+  };
+
+  /// These are values used in the bitcode files to encode AtomicRMW operations.
+  /// The values of these enums have no fixed relation to the LLVM IR enum
+  /// values.  Changing these will break compatibility with old files.
+  enum NaClRMWOperations {
+    RMW_XCHG = 0,
+    RMW_ADD = 1,
+    RMW_SUB = 2,
+    RMW_AND = 3,
+    RMW_NAND = 4,
+    RMW_OR = 5,
+    RMW_XOR = 6,
+    RMW_MAX = 7,
+    RMW_MIN = 8,
+    RMW_UMAX = 9,
+    RMW_UMIN = 10
+  };
+
+  /// OverflowingBinaryOperatorOptionalFlags - Flags for serializing
+  /// OverflowingBinaryOperator's SubclassOptionalData contents.
+  enum NaClOverflowingBinaryOperatorOptionalFlags {
+    OBO_NO_UNSIGNED_WRAP = 0,
+    OBO_NO_SIGNED_WRAP = 1
+  };
+
+  /// PossiblyExactOperatorOptionalFlags - Flags for serializing
+  /// PossiblyExactOperator's SubclassOptionalData contents.
+  enum NaClPossiblyExactOperatorOptionalFlags {
+    PEO_EXACT = 0
+  };
+
+  /// Encoded AtomicOrdering values.
+  enum NaClAtomicOrderingCodes {
+    ORDERING_NOTATOMIC = 0,
+    ORDERING_UNORDERED = 1,
+    ORDERING_MONOTONIC = 2,
+    ORDERING_ACQUIRE = 3,
+    ORDERING_RELEASE = 4,
+    ORDERING_ACQREL = 5,
+    ORDERING_SEQCST = 6
+  };
+
+  /// Encoded SynchronizationScope values.
+  enum NaClAtomicSynchScopeCodes {
+    SYNCHSCOPE_SINGLETHREAD = 0,
+    SYNCHSCOPE_CROSSTHREAD = 1
+  };
+
+  // The function body block (FUNCTION_BLOCK_ID) describes function bodies.  It
+  // can contain a constant block (CONSTANTS_BLOCK_ID).
+  enum NaClFunctionCodes {
+    FUNC_CODE_DECLAREBLOCKS    =  1, // DECLAREBLOCKS: [n]
+
+    FUNC_CODE_INST_BINOP       =  2, // BINOP:      [opcode, ty, opval, opval]
+    FUNC_CODE_INST_CAST        =  3, // CAST:       [opcode, ty, opty, opval]
+    FUNC_CODE_INST_GEP         =  4, // GEP:        [n x operands]
+    FUNC_CODE_INST_SELECT      =  5, // SELECT:     [ty, opval, opval, opval]
+    FUNC_CODE_INST_EXTRACTELT  =  6, // EXTRACTELT: [opty, opval, opval]
+    FUNC_CODE_INST_INSERTELT   =  7, // INSERTELT:  [ty, opval, opval, opval]
+    FUNC_CODE_INST_SHUFFLEVEC  =  8, // SHUFFLEVEC: [ty, opval, opval, opval]
+    FUNC_CODE_INST_CMP         =  9, // CMP:        [opty, opval, opval, pred]
+
+    FUNC_CODE_INST_RET         = 10, // RET:        [opty,opval<both optional>]
+    FUNC_CODE_INST_BR          = 11, // BR:         [bb#, bb#, cond] or [bb#]
+    FUNC_CODE_INST_SWITCH      = 12, // SWITCH:     [opty, op0, op1, ...]
+    FUNC_CODE_INST_INVOKE      = 13, // INVOKE:     [attr, fnty, op0,op1, ...]
+    // 14 is unused.
+    FUNC_CODE_INST_UNREACHABLE = 15, // UNREACHABLE
+
+    FUNC_CODE_INST_PHI         = 16, // PHI:        [ty, val0,bb0, ...]
+    // 17 is unused.
+    // 18 is unused.
+    FUNC_CODE_INST_ALLOCA      = 19, // ALLOCA:     [instty, op, align]
+    FUNC_CODE_INST_LOAD        = 20, // LOAD:       [opty, op, align, vol]
+    // 21 is unused.
+    // 22 is unused.
+    FUNC_CODE_INST_VAARG       = 23, // VAARG:      [valistty, valist, instty]
+    // This store code encodes the pointer type, rather than the value type
+    // this is so information only available in the pointer type (e.g. address
+    // spaces) is retained.
+    FUNC_CODE_INST_STORE       = 24, // STORE:      [ptrty,ptr,val, align, vol]
+    // 25 is unused.
+    FUNC_CODE_INST_EXTRACTVAL  = 26, // EXTRACTVAL: [n x operands]
+    FUNC_CODE_INST_INSERTVAL   = 27, // INSERTVAL:  [n x operands]
+    // fcmp/icmp returning Int1TY or vector of Int1Ty. Same as CMP, exists to
+    // support legacy vicmp/vfcmp instructions.
+    FUNC_CODE_INST_CMP2        = 28, // CMP2:       [opty, opval, opval, pred]
+    // new select on i1 or [N x i1]
+    FUNC_CODE_INST_VSELECT     = 29, // VSELECT:    [ty,opval,opval,predty,pred]
+    FUNC_CODE_INST_INBOUNDS_GEP= 30, // INBOUNDS_GEP: [n x operands]
+    FUNC_CODE_INST_INDIRECTBR  = 31, // INDIRECTBR: [opty, op0, op1, ...]
+    // 32 is unused.
+    FUNC_CODE_DEBUG_LOC_AGAIN  = 33, // DEBUG_LOC_AGAIN
+
+    FUNC_CODE_INST_CALL        = 34, // CALL:       [attr, fnty, fnid, args...]
+
+    FUNC_CODE_DEBUG_LOC        = 35, // DEBUG_LOC:  [Line,Col,ScopeVal, IAVal]
+    FUNC_CODE_INST_FENCE       = 36, // FENCE: [ordering, synchscope]
+    FUNC_CODE_INST_CMPXCHG     = 37, // CMPXCHG: [ptrty,ptr,cmp,new, align, vol,
+                                     //           ordering, synchscope]
+    FUNC_CODE_INST_ATOMICRMW   = 38, // ATOMICRMW: [ptrty,ptr,val, operation,
+                                     //             align, vol,
+                                     //             ordering, synchscope]
+    FUNC_CODE_INST_RESUME      = 39, // RESUME:     [opval]
+    FUNC_CODE_INST_LANDINGPAD  = 40, // LANDINGPAD: [ty,val,val,num,id0,val0...]
+    FUNC_CODE_INST_LOADATOMIC  = 41, // LOAD: [opty, op, align, vol,
+                                     //        ordering, synchscope]
+    FUNC_CODE_INST_STOREATOMIC = 42  // STORE: [ptrty,ptr,val, align, vol
+                                     //         ordering, synchscope]
+  };
+
+  enum NaClUseListCodes {
+    USELIST_CODE_ENTRY = 1   // USELIST_CODE_ENTRY: TBD.
+  };
+} // End naclbitc namespace
+} // End llvm namespace
+
+#endif
diff --git a/include/llvm/Bitcode/NaCl/NaClReaderWriter.h b/include/llvm/Bitcode/NaCl/NaClReaderWriter.h
index 2b905b97e8..d505af0a1f 100644
--- a/include/llvm/Bitcode/NaCl/NaClReaderWriter.h
+++ b/include/llvm/Bitcode/NaCl/NaClReaderWriter.h
@@ -8,22 +8,142 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This header defines interfaces to read and write LLVM bitcode files/streams.
+// This header defines interfaces to read and write NaCl bitcode wire format
+// files.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_BITCODE_NACL_NACLREADERWRITER_H
 #define LLVM_BITCODE_NACL_NACLREADERWRITER_H
 
+#include <string>
+
 namespace llvm {
+  class MemoryBuffer;
+  class DataStreamer;
+  class LLVMContext;
   class Module;
   class raw_ostream;
 
+  /// getNaClLazyBitcodeModule - Read the header of the specified bitcode buffer
+  /// and prepare for lazy deserialization of function bodies.  If successful,
+  /// this takes ownership of 'buffer' and returns a non-null pointer.  On
+  /// error, this returns null, *does not* take ownership of Buffer, and fills
+  /// in *ErrMsg with an error description if ErrMsg is non-null.
+  Module *getNaClLazyBitcodeModule(MemoryBuffer *Buffer,
+				   LLVMContext &Context,
+				   std::string *ErrMsg = 0);
+
+  /// getNaClStreamedBitcodeModule - Read the header of the specified stream
+  /// and prepare for lazy deserialization and streaming of function bodies.
+  /// On error, this returns null, and fills in *ErrMsg with an error
+  /// description if ErrMsg is non-null.
+  Module *getNaClStreamedBitcodeModule(const std::string &name,
+				       DataStreamer *streamer,
+				       LLVMContext &Context,
+				       std::string *ErrMsg = 0);
+
+  /// NaClParseBitcodeFile - Read the specified bitcode file,
+  /// returning the module.  If an error occurs, this returns null and
+  /// fills in *ErrMsg if it is non-null.  This method *never* takes
+  /// ownership of Buffer.
+  Module *NaClParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext &Context,
+			       std::string *ErrMsg = 0);
+
   /// NaClWriteBitcodeToFile - Write the specified module to the
   /// specified raw output stream, using PNaCl wire format.  For
   /// streams where it matters, the given stream should be in "binary"
   /// mode.
   void NaClWriteBitcodeToFile(const Module *M, raw_ostream &Out);
 
+  /// isNaClBitcodeWrapper - Return true if the given bytes are the
+  /// magic bytes for an LLVM IR bitcode wrapper.
+  ///
+  inline bool isNaClBitcodeWrapper(const unsigned char *BufPtr,
+                                   const unsigned char *BufEnd) {
+    // See if you can find the hidden message in the magic bytes :-).
+    // (Hint: it's a little-endian encoding.)
+    return BufPtr != BufEnd &&
+           BufPtr[0] == 0xDE &&
+           BufPtr[1] == 0xC0 &&
+           BufPtr[2] == 0x17 &&
+           BufPtr[3] == 0x0B;
+  }
+
+  /// isNaClRawBitcode - Return true if the given bytes are the magic
+  /// bytes for raw LLVM IR bitcode (without a wrapper).
+  ///
+  inline bool isNaClRawBitcode(const unsigned char *BufPtr,
+                               const unsigned char *BufEnd) {
+    // These bytes sort of have a hidden message, but it's not in
+    // little-endian this time, and it's a little redundant.
+    return BufPtr != BufEnd &&
+           BufPtr[0] == 'B' &&
+           BufPtr[1] == 'C' &&
+           BufPtr[2] == 0xc0 &&
+           BufPtr[3] == 0xde;
+  }
+
+  /// isNaClBitcode - Return true if the given bytes are the magic bytes for
+  /// LLVM IR bitcode, either with or without a wrapper.
+  ///
+  inline bool isNaClBitcode(const unsigned char *BufPtr,
+                        const unsigned char *BufEnd) {
+    return isNaClBitcodeWrapper(BufPtr, BufEnd) ||
+           isNaClRawBitcode(BufPtr, BufEnd);
+  }
+
+  /// SkipNaClBitcodeWrapperHeader - Some systems wrap bc files with a
+  /// special header for padding or other reasons.  The format of this
+  /// header is:
+  ///
+  /// struct bc_header {
+  ///   uint32_t Magic;         // 0x0B17C0DE
+  ///   uint32_t Version;       // Version, currently always 0.
+  ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
+  ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
+  ///   ... potentially other gunk ...
+  /// };
+  ///
+  /// TODO(kschimpf): Consider changing Magic and/or gunk to communicate
+  ///     file is PNaCl wire format file (rather than LLVM bitcode).
+  ///
+  /// TODO(kschimpf): Add code to read gunk in, and store it so it is
+  /// accessable.
+  ///
+  /// This function is called when we find a file with a matching magic number.
+  /// In this case, skip down to the subsection of the file that is actually a
+  /// BC file.
+  /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
+  /// contain the whole bitcode file.
+  inline bool SkipNaClBitcodeWrapperHeader(const unsigned char *&BufPtr,
+                                           const unsigned char *&BufEnd,
+                                           bool VerifyBufferSize) {
+    enum {
+      KnownHeaderSize = 4*4,  // Size of header we read.
+      OffsetField = 2*4,      // Offset in bytes to Offset field.
+      SizeField = 3*4         // Offset in bytes to Size field.
+    };
+
+    // Must contain the header!
+    if (BufEnd-BufPtr < KnownHeaderSize) return true;
+
+    unsigned Offset = ( BufPtr[OffsetField  ]        |
+                       (BufPtr[OffsetField+1] << 8)  |
+                       (BufPtr[OffsetField+2] << 16) |
+                       (BufPtr[OffsetField+3] << 24));
+    unsigned Size   = ( BufPtr[SizeField    ]        |
+                       (BufPtr[SizeField  +1] << 8)  |
+                       (BufPtr[SizeField  +2] << 16) |
+                       (BufPtr[SizeField  +3] << 24));
+
+    // Verify that Offset+Size fits in the file.
+    if (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
+      return true;
+    BufPtr += Offset;
+    BufEnd = BufPtr+Size;
+    return false;
+  }
+
 } // end llvm namespace
 #endif
diff --git a/lib/Bitcode/NaCl/CMakeLists.txt b/lib/Bitcode/NaCl/CMakeLists.txt
index 2854f037d3..5a8b272bef 100644
--- a/lib/Bitcode/NaCl/CMakeLists.txt
+++ b/lib/Bitcode/NaCl/CMakeLists.txt
@@ -1 +1,2 @@
 add_subdirectory(Writer)
+add_subdirectory(Reader)
diff --git a/lib/Bitcode/NaCl/LLVMBuild.txt b/lib/Bitcode/NaCl/LLVMBuild.txt
index 154bb0c589..a29928d2a0 100644
--- a/lib/Bitcode/NaCl/LLVMBuild.txt
+++ b/lib/Bitcode/NaCl/LLVMBuild.txt
@@ -16,7 +16,7 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = Writer
+subdirectories = Writer Reader
 
 [component_0]
 type = Group
diff --git a/lib/Bitcode/NaCl/Makefile b/lib/Bitcode/NaCl/Makefile
index a1e85e919b..5bbbc351a1 100644
--- a/lib/Bitcode/NaCl/Makefile
+++ b/lib/Bitcode/NaCl/Makefile
@@ -8,7 +8,7 @@
 ##===----------------------------------------------------------------------===##
 
 LEVEL = ../../..
-PARALLEL_DIRS = Writer
+PARALLEL_DIRS = Writer Reader
 
 include $(LEVEL)/Makefile.common
 
diff --git a/lib/Bitcode/NaCl/Reader/CMakeLists.txt b/lib/Bitcode/NaCl/Reader/CMakeLists.txt
new file mode 100644
index 0000000000..1013174307
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/CMakeLists.txt
@@ -0,0 +1,6 @@
+add_llvm_library(LLVMNaClBitReader
+  NaClBitcodeReader.cpp
+  NaClBitstreamReader.cpp
+  )
+
+add_dependencies(LLVMNaClBitReader intrinsics_gen)
diff --git a/lib/Bitcode/NaCl/Reader/LLVMBuild.txt b/lib/Bitcode/NaCl/Reader/LLVMBuild.txt
new file mode 100644
index 0000000000..acf354f5b5
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/Bitcode/NaClReader/LLVMBuild.txt -------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = NaClBitReader
+parent = NaClBitcode
+required_libraries = Core Support
diff --git a/lib/Bitcode/NaCl/Reader/Makefile b/lib/Bitcode/NaCl/Reader/Makefile
new file mode 100644
index 0000000000..92c75c29a4
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/Makefile
@@ -0,0 +1,15 @@
+##===- lib/Bitcode/NaCl/Reader/Makefile --------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../../..
+LIBRARYNAME = LLVMNaClBitReader
+BUILD_ARCHIVE = 1
+
+include $(LEVEL)/Makefile.common
+
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
new file mode 100644
index 0000000000..79b6ea6cca
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
@@ -0,0 +1,3124 @@
+//===- NaClBitcodeReader.cpp ----------------------------------------------===//
+//     Internal NaClBitcodeReader implementation
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+#include "NaClBitcodeReader.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/AutoUpgrade.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/OperandTraits.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+using namespace llvm;
+
+enum {
+  SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
+};
+
+void NaClBitcodeReader::materializeForwardReferencedFunctions() {
+  while (!BlockAddrFwdRefs.empty()) {
+    Function *F = BlockAddrFwdRefs.begin()->first;
+    F->Materialize();
+  }
+}
+
+void NaClBitcodeReader::FreeState() {
+  if (BufferOwned)
+    delete Buffer;
+  Buffer = 0;
+  std::vector<Type*>().swap(TypeList);
+  ValueList.clear();
+  MDValueList.clear();
+
+  std::vector<AttributeSet>().swap(MAttributes);
+  std::vector<BasicBlock*>().swap(FunctionBBs);
+  std::vector<Function*>().swap(FunctionsWithBodies);
+  DeferredFunctionInfo.clear();
+  MDKindMap.clear();
+
+  assert(BlockAddrFwdRefs.empty() && "Unresolved blockaddress fwd references");
+}
+
+//===----------------------------------------------------------------------===//
+//  Helper functions to implement forward reference resolution, etc.
+//===----------------------------------------------------------------------===//
+
+/// ConvertToString - Convert a string from a record into an std::string, return
+/// true on failure.
+template<typename StrTy>
+static bool ConvertToString(ArrayRef<uint64_t> Record, unsigned Idx,
+                            StrTy &Result) {
+  if (Idx > Record.size())
+    return true;
+
+  for (unsigned i = Idx, e = Record.size(); i != e; ++i)
+    Result += (char)Record[i];
+  return false;
+}
+
+static GlobalValue::LinkageTypes GetDecodedLinkage(unsigned Val) {
+  switch (Val) {
+  default: // Map unknown/new linkages to external
+  case 0:  return GlobalValue::ExternalLinkage;
+  case 1:  return GlobalValue::WeakAnyLinkage;
+  case 2:  return GlobalValue::AppendingLinkage;
+  case 3:  return GlobalValue::InternalLinkage;
+  case 4:  return GlobalValue::LinkOnceAnyLinkage;
+  case 5:  return GlobalValue::DLLImportLinkage;
+  case 6:  return GlobalValue::DLLExportLinkage;
+  case 7:  return GlobalValue::ExternalWeakLinkage;
+  case 8:  return GlobalValue::CommonLinkage;
+  case 9:  return GlobalValue::PrivateLinkage;
+  case 10: return GlobalValue::WeakODRLinkage;
+  case 11: return GlobalValue::LinkOnceODRLinkage;
+  case 12: return GlobalValue::AvailableExternallyLinkage;
+  case 13: return GlobalValue::LinkerPrivateLinkage;
+  case 14: return GlobalValue::LinkerPrivateWeakLinkage;
+  case 15: return GlobalValue::LinkOnceODRAutoHideLinkage;
+  }
+}
+
+static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
+  switch (Val) {
+  default: // Map unknown visibilities to default.
+  case 0: return GlobalValue::DefaultVisibility;
+  case 1: return GlobalValue::HiddenVisibility;
+  case 2: return GlobalValue::ProtectedVisibility;
+  }
+}
+
+static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
+  switch (Val) {
+    case 0: return GlobalVariable::NotThreadLocal;
+    default: // Map unknown non-zero value to general dynamic.
+    case 1: return GlobalVariable::GeneralDynamicTLSModel;
+    case 2: return GlobalVariable::LocalDynamicTLSModel;
+    case 3: return GlobalVariable::InitialExecTLSModel;
+    case 4: return GlobalVariable::LocalExecTLSModel;
+  }
+}
+
+static int GetDecodedCastOpcode(unsigned Val) {
+  switch (Val) {
+  default: return -1;
+  case naclbitc::CAST_TRUNC   : return Instruction::Trunc;
+  case naclbitc::CAST_ZEXT    : return Instruction::ZExt;
+  case naclbitc::CAST_SEXT    : return Instruction::SExt;
+  case naclbitc::CAST_FPTOUI  : return Instruction::FPToUI;
+  case naclbitc::CAST_FPTOSI  : return Instruction::FPToSI;
+  case naclbitc::CAST_UITOFP  : return Instruction::UIToFP;
+  case naclbitc::CAST_SITOFP  : return Instruction::SIToFP;
+  case naclbitc::CAST_FPTRUNC : return Instruction::FPTrunc;
+  case naclbitc::CAST_FPEXT   : return Instruction::FPExt;
+  case naclbitc::CAST_PTRTOINT: return Instruction::PtrToInt;
+  case naclbitc::CAST_INTTOPTR: return Instruction::IntToPtr;
+  case naclbitc::CAST_BITCAST : return Instruction::BitCast;
+  }
+}
+static int GetDecodedBinaryOpcode(unsigned Val, Type *Ty) {
+  switch (Val) {
+  default: return -1;
+  case naclbitc::BINOP_ADD:
+    return Ty->isFPOrFPVectorTy() ? Instruction::FAdd : Instruction::Add;
+  case naclbitc::BINOP_SUB:
+    return Ty->isFPOrFPVectorTy() ? Instruction::FSub : Instruction::Sub;
+  case naclbitc::BINOP_MUL:
+    return Ty->isFPOrFPVectorTy() ? Instruction::FMul : Instruction::Mul;
+  case naclbitc::BINOP_UDIV: return Instruction::UDiv;
+  case naclbitc::BINOP_SDIV:
+    return Ty->isFPOrFPVectorTy() ? Instruction::FDiv : Instruction::SDiv;
+  case naclbitc::BINOP_UREM: return Instruction::URem;
+  case naclbitc::BINOP_SREM:
+    return Ty->isFPOrFPVectorTy() ? Instruction::FRem : Instruction::SRem;
+  case naclbitc::BINOP_SHL:  return Instruction::Shl;
+  case naclbitc::BINOP_LSHR: return Instruction::LShr;
+  case naclbitc::BINOP_ASHR: return Instruction::AShr;
+  case naclbitc::BINOP_AND:  return Instruction::And;
+  case naclbitc::BINOP_OR:   return Instruction::Or;
+  case naclbitc::BINOP_XOR:  return Instruction::Xor;
+  }
+}
+
+static AtomicRMWInst::BinOp GetDecodedRMWOperation(unsigned Val) {
+  switch (Val) {
+  default: return AtomicRMWInst::BAD_BINOP;
+  case naclbitc::RMW_XCHG: return AtomicRMWInst::Xchg;
+  case naclbitc::RMW_ADD: return AtomicRMWInst::Add;
+  case naclbitc::RMW_SUB: return AtomicRMWInst::Sub;
+  case naclbitc::RMW_AND: return AtomicRMWInst::And;
+  case naclbitc::RMW_NAND: return AtomicRMWInst::Nand;
+  case naclbitc::RMW_OR: return AtomicRMWInst::Or;
+  case naclbitc::RMW_XOR: return AtomicRMWInst::Xor;
+  case naclbitc::RMW_MAX: return AtomicRMWInst::Max;
+  case naclbitc::RMW_MIN: return AtomicRMWInst::Min;
+  case naclbitc::RMW_UMAX: return AtomicRMWInst::UMax;
+  case naclbitc::RMW_UMIN: return AtomicRMWInst::UMin;
+  }
+}
+
+static AtomicOrdering GetDecodedOrdering(unsigned Val) {
+  switch (Val) {
+  case naclbitc::ORDERING_NOTATOMIC: return NotAtomic;
+  case naclbitc::ORDERING_UNORDERED: return Unordered;
+  case naclbitc::ORDERING_MONOTONIC: return Monotonic;
+  case naclbitc::ORDERING_ACQUIRE: return Acquire;
+  case naclbitc::ORDERING_RELEASE: return Release;
+  case naclbitc::ORDERING_ACQREL: return AcquireRelease;
+  default: // Map unknown orderings to sequentially-consistent.
+  case naclbitc::ORDERING_SEQCST: return SequentiallyConsistent;
+  }
+}
+
+static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
+  switch (Val) {
+  case naclbitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
+  default: // Map unknown scopes to cross-thread.
+  case naclbitc::SYNCHSCOPE_CROSSTHREAD: return CrossThread;
+  }
+}
+
+namespace llvm {
+namespace {
+  /// @brief A class for maintaining the slot number definition
+  /// as a placeholder for the actual definition for forward constants defs.
+  class ConstantPlaceHolder : public ConstantExpr {
+    void operator=(const ConstantPlaceHolder &) LLVM_DELETED_FUNCTION;
+  public:
+    // allocate space for exactly one operand
+    void *operator new(size_t s) {
+      return User::operator new(s, 1);
+    }
+    explicit ConstantPlaceHolder(Type *Ty, LLVMContext& Context)
+      : ConstantExpr(Ty, Instruction::UserOp1, &Op<0>(), 1) {
+      Op<0>() = UndefValue::get(Type::getInt32Ty(Context));
+    }
+
+    /// @brief Methods to support type inquiry through isa, cast, and dyn_cast.
+    static bool classof(const Value *V) {
+      return isa<ConstantExpr>(V) &&
+             cast<ConstantExpr>(V)->getOpcode() == Instruction::UserOp1;
+    }
+
+
+    /// Provide fast operand accessors
+    //DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+  };
+}
+
+// FIXME: can we inherit this from ConstantExpr?
+template <>
+struct OperandTraits<ConstantPlaceHolder> :
+  public FixedNumOperandTraits<ConstantPlaceHolder, 1> {
+};
+}
+
+
+void NaClBitcodeReaderValueList::AssignValue(Value *V, unsigned Idx) {
+  if (Idx == size()) {
+    push_back(V);
+    return;
+  }
+
+  if (Idx >= size())
+    resize(Idx+1);
+
+  WeakVH &OldV = ValuePtrs[Idx];
+  if (OldV == 0) {
+    OldV = V;
+    return;
+  }
+
+  // Handle constants and non-constants (e.g. instrs) differently for
+  // efficiency.
+  if (Constant *PHC = dyn_cast<Constant>(&*OldV)) {
+    ResolveConstants.push_back(std::make_pair(PHC, Idx));
+    OldV = V;
+  } else {
+    // If there was a forward reference to this value, replace it.
+    Value *PrevVal = OldV;
+    OldV->replaceAllUsesWith(V);
+    delete PrevVal;
+  }
+}
+
+
+Constant *NaClBitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
+                                                    Type *Ty) {
+  if (Idx >= size())
+    resize(Idx + 1);
+
+  if (Value *V = ValuePtrs[Idx]) {
+    assert(Ty == V->getType() && "Type mismatch in constant table!");
+    return cast<Constant>(V);
+  }
+
+  // Create and return a placeholder, which will later be RAUW'd.
+  Constant *C = new ConstantPlaceHolder(Ty, Context);
+  ValuePtrs[Idx] = C;
+  return C;
+}
+
+Value *NaClBitcodeReaderValueList::getValueFwdRef(unsigned Idx, Type *Ty) {
+  if (Idx >= size())
+    resize(Idx + 1);
+
+  if (Value *V = ValuePtrs[Idx]) {
+    assert((Ty == 0 || Ty == V->getType()) && "Type mismatch in value table!");
+    return V;
+  }
+
+  // No type specified, must be invalid reference.
+  if (Ty == 0) return 0;
+
+  // Create and return a placeholder, which will later be RAUW'd.
+  Value *V = new Argument(Ty);
+  ValuePtrs[Idx] = V;
+  return V;
+}
+
+/// ResolveConstantForwardRefs - Once all constants are read, this method bulk
+/// resolves any forward references.  The idea behind this is that we sometimes
+/// get constants (such as large arrays) which reference *many* forward ref
+/// constants.  Replacing each of these causes a lot of thrashing when
+/// building/reuniquing the constant.  Instead of doing this, we look at all the
+/// uses and rewrite all the place holders at once for any constant that uses
+/// a placeholder.
+void NaClBitcodeReaderValueList::ResolveConstantForwardRefs() {
+  // Sort the values by-pointer so that they are efficient to look up with a
+  // binary search.
+  std::sort(ResolveConstants.begin(), ResolveConstants.end());
+
+  SmallVector<Constant*, 64> NewOps;
+
+  while (!ResolveConstants.empty()) {
+    Value *RealVal = operator[](ResolveConstants.back().second);
+    Constant *Placeholder = ResolveConstants.back().first;
+    ResolveConstants.pop_back();
+
+    // Loop over all users of the placeholder, updating them to reference the
+    // new value.  If they reference more than one placeholder, update them all
+    // at once.
+    while (!Placeholder->use_empty()) {
+      Value::use_iterator UI = Placeholder->use_begin();
+      User *U = *UI;
+
+      // If the using object isn't uniqued, just update the operands.  This
+      // handles instructions and initializers for global variables.
+      if (!isa<Constant>(U) || isa<GlobalValue>(U)) {
+        UI.getUse().set(RealVal);
+        continue;
+      }
+
+      // Otherwise, we have a constant that uses the placeholder.  Replace that
+      // constant with a new constant that has *all* placeholder uses updated.
+      Constant *UserC = cast<Constant>(U);
+      for (User::op_iterator I = UserC->op_begin(), E = UserC->op_end();
+           I != E; ++I) {
+        Value *NewOp;
+        if (!isa<ConstantPlaceHolder>(*I)) {
+          // Not a placeholder reference.
+          NewOp = *I;
+        } else if (*I == Placeholder) {
+          // Common case is that it just references this one placeholder.
+          NewOp = RealVal;
+        } else {
+          // Otherwise, look up the placeholder in ResolveConstants.
+          ResolveConstantsTy::iterator It =
+            std::lower_bound(ResolveConstants.begin(), ResolveConstants.end(),
+                             std::pair<Constant*, unsigned>(cast<Constant>(*I),
+                                                            0));
+          assert(It != ResolveConstants.end() && It->first == *I);
+          NewOp = operator[](It->second);
+        }
+
+        NewOps.push_back(cast<Constant>(NewOp));
+      }
+
+      // Make the new constant.
+      Constant *NewC;
+      if (ConstantArray *UserCA = dyn_cast<ConstantArray>(UserC)) {
+        NewC = ConstantArray::get(UserCA->getType(), NewOps);
+      } else if (ConstantStruct *UserCS = dyn_cast<ConstantStruct>(UserC)) {
+        NewC = ConstantStruct::get(UserCS->getType(), NewOps);
+      } else if (isa<ConstantVector>(UserC)) {
+        NewC = ConstantVector::get(NewOps);
+      } else {
+        assert(isa<ConstantExpr>(UserC) && "Must be a ConstantExpr.");
+        NewC = cast<ConstantExpr>(UserC)->getWithOperands(NewOps);
+      }
+
+      UserC->replaceAllUsesWith(NewC);
+      UserC->destroyConstant();
+      NewOps.clear();
+    }
+
+    // Update all ValueHandles, they should be the only users at this point.
+    Placeholder->replaceAllUsesWith(RealVal);
+    delete Placeholder;
+  }
+}
+
+void NaClBitcodeReaderMDValueList::AssignValue(Value *V, unsigned Idx) {
+  if (Idx == size()) {
+    push_back(V);
+    return;
+  }
+
+  if (Idx >= size())
+    resize(Idx+1);
+
+  WeakVH &OldV = MDValuePtrs[Idx];
+  if (OldV == 0) {
+    OldV = V;
+    return;
+  }
+
+  // If there was a forward reference to this value, replace it.
+  MDNode *PrevVal = cast<MDNode>(OldV);
+  OldV->replaceAllUsesWith(V);
+  MDNode::deleteTemporary(PrevVal);
+  // Deleting PrevVal sets Idx value in MDValuePtrs to null. Set new
+  // value for Idx.
+  MDValuePtrs[Idx] = V;
+}
+
+Value *NaClBitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
+  if (Idx >= size())
+    resize(Idx + 1);
+
+  if (Value *V = MDValuePtrs[Idx]) {
+    assert(V->getType()->isMetadataTy() && "Type mismatch in value table!");
+    return V;
+  }
+
+  // Create and return a placeholder, which will later be RAUW'd.
+  Value *V = MDNode::getTemporary(Context, ArrayRef<Value*>());
+  MDValuePtrs[Idx] = V;
+  return V;
+}
+
+Type *NaClBitcodeReader::getTypeByID(unsigned ID) {
+  // The type table size is always specified correctly.
+  if (ID >= TypeList.size())
+    return 0;
+
+  if (Type *Ty = TypeList[ID])
+    return Ty;
+
+  // If we have a forward reference, the only possible case is when it is to a
+  // named struct.  Just create a placeholder for now.
+  return TypeList[ID] = StructType::create(Context);
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Functions for parsing blocks from the bitcode file
+//===----------------------------------------------------------------------===//
+
+
+/// \brief This fills an AttrBuilder object with the LLVM attributes that have
+/// been decoded from the given integer. This function must stay in sync with
+/// 'encodeLLVMAttributesForBitcode'.
+static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
+                                           uint64_t EncodedAttrs) {
+  // FIXME: Remove in 4.0.
+
+  // The alignment is stored as a 16-bit raw value from bits 31--16.  We shift
+  // the bits above 31 down by 11 bits.
+  unsigned Alignment = (EncodedAttrs & (0xffffULL << 16)) >> 16;
+  assert((!Alignment || isPowerOf2_32(Alignment)) &&
+         "Alignment must be a power of two.");
+
+  if (Alignment)
+    B.addAlignmentAttr(Alignment);
+  B.addRawValue(((EncodedAttrs & (0xfffffULL << 32)) >> 11) |
+                (EncodedAttrs & 0xffff));
+}
+
+bool NaClBitcodeReader::ParseAttributeBlock() {
+  if (Stream.EnterSubBlock(naclbitc::PARAMATTR_BLOCK_ID))
+    return Error("Malformed block record");
+
+  if (!MAttributes.empty())
+    return Error("Multiple PARAMATTR blocks found!");
+
+  SmallVector<uint64_t, 64> Record;
+
+  SmallVector<AttributeSet, 8> Attrs;
+
+  // Read all the records.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("Error at end of PARAMATTR block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default:  // Default behavior: ignore.
+      break;
+    case naclbitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
+      // FIXME: Remove in 4.0.
+      if (Record.size() & 1)
+        return Error("Invalid ENTRY record");
+
+      for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
+        AttrBuilder B;
+        decodeLLVMAttributesForBitcode(B, Record[i+1]);
+        Attrs.push_back(AttributeSet::get(Context, Record[i], B));
+      }
+
+      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      Attrs.clear();
+      break;
+    }
+    case naclbitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [attrgrp0, attrgrp1, ...]
+      for (unsigned i = 0, e = Record.size(); i != e; ++i)
+        Attrs.push_back(MAttributeGroups[Record[i]]);
+
+      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      Attrs.clear();
+      break;
+    }
+    }
+  }
+}
+
+bool NaClBitcodeReader::ParseAttributeGroupBlock() {
+  if (Stream.EnterSubBlock(naclbitc::PARAMATTR_GROUP_BLOCK_ID))
+    return Error("Malformed block record");
+
+  if (!MAttributeGroups.empty())
+    return Error("Multiple PARAMATTR_GROUP blocks found!");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("Error at end of PARAMATTR_GROUP block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default:  // Default behavior: ignore.
+      break;
+    case naclbitc::PARAMATTR_GRP_CODE_ENTRY: {
+      // ENTRY: [grpid, idx, a0, a1, ...]
+      if (Record.size() < 3)
+        return Error("Invalid ENTRY record");
+
+      uint64_t GrpID = Record[0];
+      uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
+
+      AttrBuilder B;
+      for (unsigned i = 2, e = Record.size(); i != e; ++i) {
+        if (Record[i] == 0) {        // Enum attribute
+          B.addAttribute(Attribute::AttrKind(Record[++i]));
+        } else if (Record[i] == 1) { // Align attribute
+          if (Attribute::AttrKind(Record[++i]) == Attribute::Alignment)
+            B.addAlignmentAttr(Record[++i]);
+          else
+            B.addStackAlignmentAttr(Record[++i]);
+        } else {                     // String attribute
+          assert((Record[i] == 3 || Record[i] == 4) &&
+                 "Invalid attribute group entry");
+          bool HasValue = (Record[i++] == 4);
+          SmallString<64> KindStr;
+          SmallString<64> ValStr;
+
+          while (Record[i] != 0 && i != e)
+            KindStr += Record[i++];
+          assert(Record[i] == 0 && "Kind string not null terminated");
+
+          if (HasValue) {
+            // Has a value associated with it.
+            ++i; // Skip the '0' that terminates the "kind" string.
+            while (Record[i] != 0 && i != e)
+              ValStr += Record[i++];
+            assert(Record[i] == 0 && "Value string not null terminated");
+          }
+
+          B.addAttribute(KindStr.str(), ValStr.str());
+        }
+      }
+
+      MAttributeGroups[GrpID] = AttributeSet::get(Context, Idx, B);
+      break;
+    }
+    }
+  }
+}
+
+bool NaClBitcodeReader::ParseTypeTable() {
+  if (Stream.EnterSubBlock(naclbitc::TYPE_BLOCK_ID_NEW))
+    return Error("Malformed block record");
+
+  return ParseTypeTableBody();
+}
+
+bool NaClBitcodeReader::ParseTypeTableBody() {
+  if (!TypeList.empty())
+    return Error("Multiple TYPE_BLOCKs found!");
+
+  SmallVector<uint64_t, 64> Record;
+  unsigned NumRecords = 0;
+
+  SmallString<64> TypeName;
+
+  // Read all the records for this type table.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      Error("Error in the type table block");
+      return true;
+    case NaClBitstreamEntry::EndBlock:
+      if (NumRecords != TypeList.size())
+        return Error("Invalid type forward reference in TYPE_BLOCK");
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    Type *ResultTy = 0;
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default: return Error("unknown type in type table");
+    case naclbitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
+      // TYPE_CODE_NUMENTRY contains a count of the number of types in the
+      // type list.  This allows us to reserve space.
+      if (Record.size() < 1)
+        return Error("Invalid TYPE_CODE_NUMENTRY record");
+      TypeList.resize(Record[0]);
+      continue;
+    case naclbitc::TYPE_CODE_VOID:      // VOID
+      ResultTy = Type::getVoidTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_HALF:     // HALF
+      ResultTy = Type::getHalfTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_FLOAT:     // FLOAT
+      ResultTy = Type::getFloatTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_DOUBLE:    // DOUBLE
+      ResultTy = Type::getDoubleTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_X86_FP80:  // X86_FP80
+      ResultTy = Type::getX86_FP80Ty(Context);
+      break;
+    case naclbitc::TYPE_CODE_FP128:     // FP128
+      ResultTy = Type::getFP128Ty(Context);
+      break;
+    case naclbitc::TYPE_CODE_PPC_FP128: // PPC_FP128
+      ResultTy = Type::getPPC_FP128Ty(Context);
+      break;
+    case naclbitc::TYPE_CODE_LABEL:     // LABEL
+      ResultTy = Type::getLabelTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_METADATA:  // METADATA
+      ResultTy = Type::getMetadataTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_X86_MMX:   // X86_MMX
+      ResultTy = Type::getX86_MMXTy(Context);
+      break;
+    case naclbitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
+      if (Record.size() < 1)
+        return Error("Invalid Integer type record");
+
+      ResultTy = IntegerType::get(Context, Record[0]);
+      break;
+    case naclbitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
+                                    //          [pointee type, address space]
+      if (Record.size() < 1)
+        return Error("Invalid POINTER type record");
+      unsigned AddressSpace = 0;
+      if (Record.size() == 2)
+        AddressSpace = Record[1];
+      ResultTy = getTypeByID(Record[0]);
+      if (ResultTy == 0) return Error("invalid element type in pointer type");
+      ResultTy = PointerType::get(ResultTy, AddressSpace);
+      break;
+    }
+    case naclbitc::TYPE_CODE_FUNCTION_OLD: {
+      // FIXME: attrid is dead, remove it in LLVM 4.0
+      // FUNCTION: [vararg, attrid, retty, paramty x N]
+      if (Record.size() < 3)
+        return Error("Invalid FUNCTION type record");
+      SmallVector<Type*, 8> ArgTys;
+      for (unsigned i = 3, e = Record.size(); i != e; ++i) {
+        if (Type *T = getTypeByID(Record[i]))
+          ArgTys.push_back(T);
+        else
+          break;
+      }
+
+      ResultTy = getTypeByID(Record[2]);
+      if (ResultTy == 0 || ArgTys.size() < Record.size()-3)
+        return Error("invalid type in function type");
+
+      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
+      break;
+    }
+    case naclbitc::TYPE_CODE_FUNCTION: {
+      // FUNCTION: [vararg, retty, paramty x N]
+      if (Record.size() < 2)
+        return Error("Invalid FUNCTION type record");
+      SmallVector<Type*, 8> ArgTys;
+      for (unsigned i = 2, e = Record.size(); i != e; ++i) {
+        if (Type *T = getTypeByID(Record[i]))
+          ArgTys.push_back(T);
+        else
+          break;
+      }
+
+      ResultTy = getTypeByID(Record[1]);
+      if (ResultTy == 0 || ArgTys.size() < Record.size()-2)
+        return Error("invalid type in function type");
+
+      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
+      break;
+    }
+    case naclbitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
+      if (Record.size() < 1)
+        return Error("Invalid STRUCT type record");
+      SmallVector<Type*, 8> EltTys;
+      for (unsigned i = 1, e = Record.size(); i != e; ++i) {
+        if (Type *T = getTypeByID(Record[i]))
+          EltTys.push_back(T);
+        else
+          break;
+      }
+      if (EltTys.size() != Record.size()-1)
+        return Error("invalid type in struct type");
+      ResultTy = StructType::get(Context, EltTys, Record[0]);
+      break;
+    }
+    case naclbitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
+      if (ConvertToString(Record, 0, TypeName))
+        return Error("Invalid STRUCT_NAME record");
+      continue;
+
+    case naclbitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
+      if (Record.size() < 1)
+        return Error("Invalid STRUCT type record");
+
+      if (NumRecords >= TypeList.size())
+        return Error("invalid TYPE table");
+
+      // Check to see if this was forward referenced, if so fill in the temp.
+      StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
+      if (Res) {
+        Res->setName(TypeName);
+        TypeList[NumRecords] = 0;
+      } else  // Otherwise, create a new struct.
+        Res = StructType::create(Context, TypeName);
+      TypeName.clear();
+
+      SmallVector<Type*, 8> EltTys;
+      for (unsigned i = 1, e = Record.size(); i != e; ++i) {
+        if (Type *T = getTypeByID(Record[i]))
+          EltTys.push_back(T);
+        else
+          break;
+      }
+      if (EltTys.size() != Record.size()-1)
+        return Error("invalid STRUCT type record");
+      Res->setBody(EltTys, Record[0]);
+      ResultTy = Res;
+      break;
+    }
+    case naclbitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
+      if (Record.size() != 1)
+        return Error("Invalid OPAQUE type record");
+
+      if (NumRecords >= TypeList.size())
+        return Error("invalid TYPE table");
+
+      // Check to see if this was forward referenced, if so fill in the temp.
+      StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
+      if (Res) {
+        Res->setName(TypeName);
+        TypeList[NumRecords] = 0;
+      } else  // Otherwise, create a new struct with no body.
+        Res = StructType::create(Context, TypeName);
+      TypeName.clear();
+      ResultTy = Res;
+      break;
+    }
+    case naclbitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
+      if (Record.size() < 2)
+        return Error("Invalid ARRAY type record");
+      if ((ResultTy = getTypeByID(Record[1])))
+        ResultTy = ArrayType::get(ResultTy, Record[0]);
+      else
+        return Error("Invalid ARRAY type element");
+      break;
+    case naclbitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
+      if (Record.size() < 2)
+        return Error("Invalid VECTOR type record");
+      if ((ResultTy = getTypeByID(Record[1])))
+        ResultTy = VectorType::get(ResultTy, Record[0]);
+      else
+        return Error("Invalid ARRAY type element");
+      break;
+    }
+
+    if (NumRecords >= TypeList.size())
+      return Error("invalid TYPE table");
+    assert(ResultTy && "Didn't read a type?");
+    assert(TypeList[NumRecords] == 0 && "Already read type?");
+    TypeList[NumRecords++] = ResultTy;
+  }
+}
+
+bool NaClBitcodeReader::ParseValueSymbolTable() {
+  if (Stream.EnterSubBlock(naclbitc::VALUE_SYMTAB_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records for this value table.
+  SmallString<128> ValueName;
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("malformed value symbol table block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default:  // Default behavior: unknown type.
+      break;
+    case naclbitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
+      if (ConvertToString(Record, 1, ValueName))
+        return Error("Invalid VST_ENTRY record");
+      unsigned ValueID = Record[0];
+      if (ValueID >= ValueList.size())
+        return Error("Invalid Value ID in VST_ENTRY record");
+      Value *V = ValueList[ValueID];
+
+      V->setName(StringRef(ValueName.data(), ValueName.size()));
+      ValueName.clear();
+      break;
+    }
+    case naclbitc::VST_CODE_BBENTRY: {
+      if (ConvertToString(Record, 1, ValueName))
+        return Error("Invalid VST_BBENTRY record");
+      BasicBlock *BB = getBasicBlock(Record[0]);
+      if (BB == 0)
+        return Error("Invalid BB ID in VST_BBENTRY record");
+
+      BB->setName(StringRef(ValueName.data(), ValueName.size()));
+      ValueName.clear();
+      break;
+    }
+    }
+  }
+}
+
+bool NaClBitcodeReader::ParseMetadata() {
+  unsigned NextMDValueNo = MDValueList.size();
+
+  if (Stream.EnterSubBlock(naclbitc::METADATA_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      Error("malformed metadata block");
+      return true;
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    bool IsFunctionLocal = false;
+    // Read a record.
+    Record.clear();
+    unsigned Code = Stream.readRecord(Entry.ID, Record);
+    switch (Code) {
+    default:  // Default behavior: ignore.
+      break;
+    case naclbitc::METADATA_NAME: {
+      // Read name of the named metadata.
+      SmallString<8> Name(Record.begin(), Record.end());
+      Record.clear();
+      Code = Stream.ReadCode();
+
+      // METADATA_NAME is always followed by METADATA_NAMED_NODE.
+      unsigned NextBitCode = Stream.readRecord(Code, Record);
+      assert(NextBitCode == naclbitc::METADATA_NAMED_NODE); (void)NextBitCode;
+
+      // Read named metadata elements.
+      unsigned Size = Record.size();
+      NamedMDNode *NMD = TheModule->getOrInsertNamedMetadata(Name);
+      for (unsigned i = 0; i != Size; ++i) {
+        MDNode *MD = dyn_cast<MDNode>(MDValueList.getValueFwdRef(Record[i]));
+        if (MD == 0)
+          return Error("Malformed metadata record");
+        NMD->addOperand(MD);
+      }
+      break;
+    }
+    case naclbitc::METADATA_FN_NODE:
+      IsFunctionLocal = true;
+      // fall-through
+    case naclbitc::METADATA_NODE: {
+      if (Record.size() % 2 == 1)
+        return Error("Invalid METADATA_NODE record");
+
+      unsigned Size = Record.size();
+      SmallVector<Value*, 8> Elts;
+      for (unsigned i = 0; i != Size; i += 2) {
+        Type *Ty = getTypeByID(Record[i]);
+        if (!Ty) return Error("Invalid METADATA_NODE record");
+        if (Ty->isMetadataTy())
+          Elts.push_back(MDValueList.getValueFwdRef(Record[i+1]));
+        else if (!Ty->isVoidTy())
+          Elts.push_back(ValueList.getValueFwdRef(Record[i+1], Ty));
+        else
+          Elts.push_back(NULL);
+      }
+      Value *V = MDNode::getWhenValsUnresolved(Context, Elts, IsFunctionLocal);
+      IsFunctionLocal = false;
+      MDValueList.AssignValue(V, NextMDValueNo++);
+      break;
+    }
+    case naclbitc::METADATA_STRING: {
+      SmallString<8> String(Record.begin(), Record.end());
+      Value *V = MDString::get(Context, String);
+      MDValueList.AssignValue(V, NextMDValueNo++);
+      break;
+    }
+    case naclbitc::METADATA_KIND: {
+      if (Record.size() < 2)
+        return Error("Invalid METADATA_KIND record");
+
+      unsigned Kind = Record[0];
+      SmallString<8> Name(Record.begin()+1, Record.end());
+
+      unsigned NewKind = TheModule->getMDKindID(Name.str());
+      if (!MDKindMap.insert(std::make_pair(Kind, NewKind)).second)
+        return Error("Conflicting METADATA_KIND records");
+      break;
+    }
+    }
+  }
+}
+
+/// decodeSignRotatedValue - Decode a signed value stored with the sign bit in
+/// the LSB for dense VBR encoding.
+uint64_t NaClBitcodeReader::decodeSignRotatedValue(uint64_t V) {
+  if ((V & 1) == 0)
+    return V >> 1;
+  if (V != 1)
+    return -(V >> 1);
+  // There is no such thing as -0 with integers.  "-0" really means MININT.
+  return 1ULL << 63;
+}
+
+/// ResolveGlobalAndAliasInits - Resolve all of the initializers for global
+/// values and aliases that we can.
+bool NaClBitcodeReader::ResolveGlobalAndAliasInits() {
+  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
+  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
+
+  GlobalInitWorklist.swap(GlobalInits);
+  AliasInitWorklist.swap(AliasInits);
+
+  while (!GlobalInitWorklist.empty()) {
+    unsigned ValID = GlobalInitWorklist.back().second;
+    if (ValID >= ValueList.size()) {
+      // Not ready to resolve this yet, it requires something later in the file.
+      GlobalInits.push_back(GlobalInitWorklist.back());
+    } else {
+      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+        GlobalInitWorklist.back().first->setInitializer(C);
+      else
+        return Error("Global variable initializer is not a constant!");
+    }
+    GlobalInitWorklist.pop_back();
+  }
+
+  while (!AliasInitWorklist.empty()) {
+    unsigned ValID = AliasInitWorklist.back().second;
+    if (ValID >= ValueList.size()) {
+      AliasInits.push_back(AliasInitWorklist.back());
+    } else {
+      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+        AliasInitWorklist.back().first->setAliasee(C);
+      else
+        return Error("Alias initializer is not a constant!");
+    }
+    AliasInitWorklist.pop_back();
+  }
+  return false;
+}
+
+static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
+  SmallVector<uint64_t, 8> Words(Vals.size());
+  std::transform(Vals.begin(), Vals.end(), Words.begin(),
+                 NaClBitcodeReader::decodeSignRotatedValue);
+
+  return APInt(TypeBits, Words);
+}
+
+bool NaClBitcodeReader::ParseConstants() {
+  if (Stream.EnterSubBlock(naclbitc::CONSTANTS_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records for this value table.
+  Type *CurTy = Type::getInt32Ty(Context);
+  unsigned NextCstNo = ValueList.size();
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("malformed block record in AST file");
+    case NaClBitstreamEntry::EndBlock:
+      if (NextCstNo != ValueList.size())
+        return Error("Invalid constant reference!");
+
+      // Once all the constants have been read, go through and resolve forward
+      // references.
+      ValueList.ResolveConstantForwardRefs();
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    Value *V = 0;
+    unsigned BitCode = Stream.readRecord(Entry.ID, Record);
+    switch (BitCode) {
+    default:  // Default behavior: unknown constant
+    case naclbitc::CST_CODE_UNDEF:     // UNDEF
+      V = UndefValue::get(CurTy);
+      break;
+    case naclbitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
+      if (Record.empty())
+        return Error("Malformed CST_SETTYPE record");
+      if (Record[0] >= TypeList.size())
+        return Error("Invalid Type ID in CST_SETTYPE record");
+      CurTy = TypeList[Record[0]];
+      continue;  // Skip the ValueList manipulation.
+    case naclbitc::CST_CODE_NULL:      // NULL
+      V = Constant::getNullValue(CurTy);
+      break;
+    case naclbitc::CST_CODE_INTEGER:   // INTEGER: [intval]
+      if (!CurTy->isIntegerTy() || Record.empty())
+        return Error("Invalid CST_INTEGER record");
+      V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
+      break;
+    case naclbitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
+      if (!CurTy->isIntegerTy() || Record.empty())
+        return Error("Invalid WIDE_INTEGER record");
+
+      APInt VInt = ReadWideAPInt(Record,
+                                 cast<IntegerType>(CurTy)->getBitWidth());
+      V = ConstantInt::get(Context, VInt);
+
+      break;
+    }
+    case naclbitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
+      if (Record.empty())
+        return Error("Invalid FLOAT record");
+      if (CurTy->isHalfTy())
+        V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf,
+                                             APInt(16, (uint16_t)Record[0])));
+      else if (CurTy->isFloatTy())
+        V = ConstantFP::get(Context, APFloat(APFloat::IEEEsingle,
+                                             APInt(32, (uint32_t)Record[0])));
+      else if (CurTy->isDoubleTy())
+        V = ConstantFP::get(Context, APFloat(APFloat::IEEEdouble,
+                                             APInt(64, Record[0])));
+      else if (CurTy->isX86_FP80Ty()) {
+        // Bits are not stored the same way as a normal i80 APInt, compensate.
+        uint64_t Rearrange[2];
+        Rearrange[0] = (Record[1] & 0xffffLL) | (Record[0] << 16);
+        Rearrange[1] = Record[0] >> 48;
+        V = ConstantFP::get(Context, APFloat(APFloat::x87DoubleExtended,
+                                             APInt(80, Rearrange)));
+      } else if (CurTy->isFP128Ty())
+        V = ConstantFP::get(Context, APFloat(APFloat::IEEEquad,
+                                             APInt(128, Record)));
+      else if (CurTy->isPPC_FP128Ty())
+        V = ConstantFP::get(Context, APFloat(APFloat::PPCDoubleDouble,
+                                             APInt(128, Record)));
+      else
+        V = UndefValue::get(CurTy);
+      break;
+    }
+
+    case naclbitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
+      if (Record.empty())
+        return Error("Invalid CST_AGGREGATE record");
+
+      unsigned Size = Record.size();
+      SmallVector<Constant*, 16> Elts;
+
+      if (StructType *STy = dyn_cast<StructType>(CurTy)) {
+        for (unsigned i = 0; i != Size; ++i)
+          Elts.push_back(ValueList.getConstantFwdRef(Record[i],
+                                                     STy->getElementType(i)));
+        V = ConstantStruct::get(STy, Elts);
+      } else if (ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
+        Type *EltTy = ATy->getElementType();
+        for (unsigned i = 0; i != Size; ++i)
+          Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
+        V = ConstantArray::get(ATy, Elts);
+      } else if (VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
+        Type *EltTy = VTy->getElementType();
+        for (unsigned i = 0; i != Size; ++i)
+          Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
+        V = ConstantVector::get(Elts);
+      } else {
+        V = UndefValue::get(CurTy);
+      }
+      break;
+    }
+    case naclbitc::CST_CODE_STRING:    // STRING: [values]
+    case naclbitc::CST_CODE_CSTRING: { // CSTRING: [values]
+      if (Record.empty())
+        return Error("Invalid CST_STRING record");
+
+      SmallString<16> Elts(Record.begin(), Record.end());
+      V = ConstantDataArray::getString(Context, Elts,
+                                       BitCode == naclbitc::CST_CODE_CSTRING);
+      break;
+    }
+    case naclbitc::CST_CODE_DATA: {// DATA: [n x value]
+      if (Record.empty())
+        return Error("Invalid CST_DATA record");
+
+      Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
+      unsigned Size = Record.size();
+
+      if (EltTy->isIntegerTy(8)) {
+        SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(16)) {
+        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(32)) {
+        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(64)) {
+        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isFloatTy()) {
+        SmallVector<float, 16> Elts(Size);
+        std::transform(Record.begin(), Record.end(), Elts.begin(), BitsToFloat);
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isDoubleTy()) {
+        SmallVector<double, 16> Elts(Size);
+        std::transform(Record.begin(), Record.end(), Elts.begin(),
+                       BitsToDouble);
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else {
+        return Error("Unknown element type in CE_DATA");
+      }
+      break;
+    }
+
+    case naclbitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
+      if (Record.size() < 3) return Error("Invalid CE_BINOP record");
+      int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
+      if (Opc < 0) {
+        V = UndefValue::get(CurTy);  // Unknown binop.
+      } else {
+        Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
+        Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
+        unsigned Flags = 0;
+        if (Record.size() >= 4) {
+          if (Opc == Instruction::Add ||
+              Opc == Instruction::Sub ||
+              Opc == Instruction::Mul ||
+              Opc == Instruction::Shl) {
+            if (Record[3] & (1 << naclbitc::OBO_NO_SIGNED_WRAP))
+              Flags |= OverflowingBinaryOperator::NoSignedWrap;
+            if (Record[3] & (1 << naclbitc::OBO_NO_UNSIGNED_WRAP))
+              Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
+          } else if (Opc == Instruction::SDiv ||
+                     Opc == Instruction::UDiv ||
+                     Opc == Instruction::LShr ||
+                     Opc == Instruction::AShr) {
+            if (Record[3] & (1 << naclbitc::PEO_EXACT))
+              Flags |= SDivOperator::IsExact;
+          }
+        }
+        V = ConstantExpr::get(Opc, LHS, RHS, Flags);
+      }
+      break;
+    }
+    case naclbitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
+      if (Record.size() < 3) return Error("Invalid CE_CAST record");
+      int Opc = GetDecodedCastOpcode(Record[0]);
+      if (Opc < 0) {
+        V = UndefValue::get(CurTy);  // Unknown cast.
+      } else {
+        Type *OpTy = getTypeByID(Record[1]);
+        if (!OpTy) return Error("Invalid CE_CAST record");
+        Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
+        V = ConstantExpr::getCast(Opc, Op, CurTy);
+      }
+      break;
+    }
+    case naclbitc::CST_CODE_CE_INBOUNDS_GEP:
+    case naclbitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
+      if (Record.size() & 1) return Error("Invalid CE_GEP record");
+      SmallVector<Constant*, 16> Elts;
+      for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
+        Type *ElTy = getTypeByID(Record[i]);
+        if (!ElTy) return Error("Invalid CE_GEP record");
+        Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
+      }
+      ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
+      V = ConstantExpr::getGetElementPtr(Elts[0], Indices,
+                                         BitCode ==
+                                           naclbitc::CST_CODE_CE_INBOUNDS_GEP);
+      break;
+    }
+    case naclbitc::CST_CODE_CE_SELECT:  // CE_SELECT: [opval#, opval#, opval#]
+      if (Record.size() < 3) return Error("Invalid CE_SELECT record");
+      V = ConstantExpr::getSelect(
+                          ValueList.getConstantFwdRef(Record[0],
+                                                      Type::getInt1Ty(Context)),
+                          ValueList.getConstantFwdRef(Record[1],CurTy),
+                          ValueList.getConstantFwdRef(Record[2],CurTy));
+      break;
+    case naclbitc::CST_CODE_CE_EXTRACTELT: {
+      // CE_EXTRACTELT: [opty, opval, opval]
+      if (Record.size() < 3) return Error("Invalid CE_EXTRACTELT record");
+      VectorType *OpTy =
+        dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
+      if (OpTy == 0) return Error("Invalid CE_EXTRACTELT record");
+      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
+      Constant *Op1 = ValueList.getConstantFwdRef(Record[2],
+                                                  Type::getInt32Ty(Context));
+      V = ConstantExpr::getExtractElement(Op0, Op1);
+      break;
+    }
+    case naclbitc::CST_CODE_CE_INSERTELT: {// CE_INSERTELT: [opval, opval, opval]
+      VectorType *OpTy = dyn_cast<VectorType>(CurTy);
+      if (Record.size() < 3 || OpTy == 0)
+        return Error("Invalid CE_INSERTELT record");
+      Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
+      Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
+                                                  OpTy->getElementType());
+      Constant *Op2 = ValueList.getConstantFwdRef(Record[2],
+                                                  Type::getInt32Ty(Context));
+      V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
+      break;
+    }
+    case naclbitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
+      VectorType *OpTy = dyn_cast<VectorType>(CurTy);
+      if (Record.size() < 3 || OpTy == 0)
+        return Error("Invalid CE_SHUFFLEVEC record");
+      Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
+      Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
+      Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
+                                                 OpTy->getNumElements());
+      Constant *Op2 = ValueList.getConstantFwdRef(Record[2], ShufTy);
+      V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
+      break;
+    }
+    case naclbitc::CST_CODE_CE_SHUFVEC_EX: { // [opty, opval, opval, opval]
+      VectorType *RTy = dyn_cast<VectorType>(CurTy);
+      VectorType *OpTy =
+        dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
+      if (Record.size() < 4 || RTy == 0 || OpTy == 0)
+        return Error("Invalid CE_SHUFVEC_EX record");
+      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
+      Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
+      Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
+                                                 RTy->getNumElements());
+      Constant *Op2 = ValueList.getConstantFwdRef(Record[3], ShufTy);
+      V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
+      break;
+    }
+    case naclbitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
+      if (Record.size() < 4) return Error("Invalid CE_CMP record");
+      Type *OpTy = getTypeByID(Record[0]);
+      if (OpTy == 0) return Error("Invalid CE_CMP record");
+      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
+      Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
+
+      if (OpTy->isFPOrFPVectorTy())
+        V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
+      else
+        V = ConstantExpr::getICmp(Record[3], Op0, Op1);
+      break;
+    }
+    // This maintains backward compatibility, pre-asm dialect keywords.
+    // FIXME: Remove with the 4.0 release.
+    case naclbitc::CST_CODE_INLINEASM_OLD: {
+      if (Record.size() < 2) return Error("Invalid INLINEASM record");
+      std::string AsmStr, ConstrStr;
+      bool HasSideEffects = Record[0] & 1;
+      bool IsAlignStack = Record[0] >> 1;
+      unsigned AsmStrSize = Record[1];
+      if (2+AsmStrSize >= Record.size())
+        return Error("Invalid INLINEASM record");
+      unsigned ConstStrSize = Record[2+AsmStrSize];
+      if (3+AsmStrSize+ConstStrSize > Record.size())
+        return Error("Invalid INLINEASM record");
+
+      for (unsigned i = 0; i != AsmStrSize; ++i)
+        AsmStr += (char)Record[2+i];
+      for (unsigned i = 0; i != ConstStrSize; ++i)
+        ConstrStr += (char)Record[3+AsmStrSize+i];
+      PointerType *PTy = cast<PointerType>(CurTy);
+      V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
+                         AsmStr, ConstrStr, HasSideEffects, IsAlignStack);
+      break;
+    }
+    // This version adds support for the asm dialect keywords (e.g.,
+    // inteldialect).
+    case naclbitc::CST_CODE_INLINEASM: {
+      if (Record.size() < 2) return Error("Invalid INLINEASM record");
+      std::string AsmStr, ConstrStr;
+      bool HasSideEffects = Record[0] & 1;
+      bool IsAlignStack = (Record[0] >> 1) & 1;
+      unsigned AsmDialect = Record[0] >> 2;
+      unsigned AsmStrSize = Record[1];
+      if (2+AsmStrSize >= Record.size())
+        return Error("Invalid INLINEASM record");
+      unsigned ConstStrSize = Record[2+AsmStrSize];
+      if (3+AsmStrSize+ConstStrSize > Record.size())
+        return Error("Invalid INLINEASM record");
+
+      for (unsigned i = 0; i != AsmStrSize; ++i)
+        AsmStr += (char)Record[2+i];
+      for (unsigned i = 0; i != ConstStrSize; ++i)
+        ConstrStr += (char)Record[3+AsmStrSize+i];
+      PointerType *PTy = cast<PointerType>(CurTy);
+      V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
+                         AsmStr, ConstrStr, HasSideEffects, IsAlignStack,
+                         InlineAsm::AsmDialect(AsmDialect));
+      break;
+    }
+    case naclbitc::CST_CODE_BLOCKADDRESS:{
+      if (Record.size() < 3) return Error("Invalid CE_BLOCKADDRESS record");
+      Type *FnTy = getTypeByID(Record[0]);
+      if (FnTy == 0) return Error("Invalid CE_BLOCKADDRESS record");
+      Function *Fn =
+        dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
+      if (Fn == 0) return Error("Invalid CE_BLOCKADDRESS record");
+
+      // If the function is already parsed we can insert the block address right
+      // away.
+      if (!Fn->empty()) {
+        Function::iterator BBI = Fn->begin(), BBE = Fn->end();
+        for (size_t I = 0, E = Record[2]; I != E; ++I) {
+          if (BBI == BBE)
+            return Error("Invalid blockaddress block #");
+          ++BBI;
+        }
+        V = BlockAddress::get(Fn, BBI);
+      } else {
+        // Otherwise insert a placeholder and remember it so it can be inserted
+        // when the function is parsed.
+        GlobalVariable *FwdRef = new GlobalVariable(*Fn->getParent(),
+                                                    Type::getInt8Ty(Context),
+                                            false, GlobalValue::InternalLinkage,
+                                                    0, "");
+        BlockAddrFwdRefs[Fn].push_back(std::make_pair(Record[2], FwdRef));
+        V = FwdRef;
+      }
+      break;
+    }
+    }
+
+    ValueList.AssignValue(V, NextCstNo);
+    ++NextCstNo;
+  }
+}
+
+bool NaClBitcodeReader::ParseUseLists() {
+  if (Stream.EnterSubBlock(naclbitc::USELIST_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("malformed use list block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a use list record.
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default:  // Default behavior: unknown type.
+      break;
+    case naclbitc::USELIST_CODE_ENTRY: { // USELIST_CODE_ENTRY: TBD.
+      unsigned RecordLength = Record.size();
+      if (RecordLength < 1)
+        return Error ("Invalid UseList reader!");
+      UseListRecords.push_back(Record);
+      break;
+    }
+    }
+  }
+}
+
+/// RememberAndSkipFunctionBody - When we see the block for a function body,
+/// remember where it is and then skip it.  This lets us lazily deserialize the
+/// functions.
+bool NaClBitcodeReader::RememberAndSkipFunctionBody() {
+  // Get the function we are talking about.
+  if (FunctionsWithBodies.empty())
+    return Error("Insufficient function protos");
+
+  Function *Fn = FunctionsWithBodies.back();
+  FunctionsWithBodies.pop_back();
+
+  // Save the current stream state.
+  uint64_t CurBit = Stream.GetCurrentBitNo();
+  DeferredFunctionInfo[Fn] = CurBit;
+
+  // Skip over the function block for now.
+  if (Stream.SkipBlock())
+    return Error("Malformed block record");
+  return false;
+}
+
+bool NaClBitcodeReader::GlobalCleanup() {
+  // Patch the initializers for globals and aliases up.
+  ResolveGlobalAndAliasInits();
+  if (!GlobalInits.empty() || !AliasInits.empty())
+    return Error("Malformed global initializer set");
+
+  // Look for intrinsic functions which need to be upgraded at some point
+  for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
+       FI != FE; ++FI) {
+    Function *NewFn;
+    if (UpgradeIntrinsicFunction(FI, NewFn))
+      UpgradedIntrinsics.push_back(std::make_pair(FI, NewFn));
+  }
+
+  // Look for global variables which need to be renamed.
+  for (Module::global_iterator
+         GI = TheModule->global_begin(), GE = TheModule->global_end();
+       GI != GE; ++GI)
+    UpgradeGlobalVariable(GI);
+  // Force deallocation of memory for these vectors to favor the client that
+  // want lazy deserialization.
+  std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
+  std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
+  return false;
+}
+
+bool NaClBitcodeReader::ParseModule(bool Resume) {
+  if (Resume)
+    Stream.JumpToBit(NextUnreadBit);
+  else if (Stream.EnterSubBlock(naclbitc::MODULE_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+  std::vector<std::string> SectionTable;
+  std::vector<std::string> GCTable;
+
+  // Read all the records for this module.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      Error("malformed module block");
+      return true;
+    case NaClBitstreamEntry::EndBlock:
+      return GlobalCleanup();
+
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      default:  // Skip unknown content.
+        if (Stream.SkipBlock())
+          return Error("Malformed block record");
+        break;
+      case bitc::BLOCKINFO_BLOCK_ID:
+        if (Stream.ReadBlockInfoBlock())
+          return Error("Malformed BlockInfoBlock");
+        break;
+      case naclbitc::PARAMATTR_BLOCK_ID:
+        if (ParseAttributeBlock())
+          return true;
+        break;
+      case naclbitc::PARAMATTR_GROUP_BLOCK_ID:
+        if (ParseAttributeGroupBlock())
+          return true;
+        break;
+      case naclbitc::TYPE_BLOCK_ID_NEW:
+        if (ParseTypeTable())
+          return true;
+        break;
+      case naclbitc::VALUE_SYMTAB_BLOCK_ID:
+        if (ParseValueSymbolTable())
+          return true;
+        SeenValueSymbolTable = true;
+        break;
+      case naclbitc::CONSTANTS_BLOCK_ID:
+        if (ParseConstants() || ResolveGlobalAndAliasInits())
+          return true;
+        break;
+      case naclbitc::METADATA_BLOCK_ID:
+        if (ParseMetadata())
+          return true;
+        break;
+      case naclbitc::FUNCTION_BLOCK_ID:
+        // If this is the first function body we've seen, reverse the
+        // FunctionsWithBodies list.
+        if (!SeenFirstFunctionBody) {
+          std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
+          if (GlobalCleanup())
+            return true;
+          SeenFirstFunctionBody = true;
+        }
+
+        if (RememberAndSkipFunctionBody())
+          return true;
+        // For streaming bitcode, suspend parsing when we reach the function
+        // bodies. Subsequent materialization calls will resume it when
+        // necessary. For streaming, the function bodies must be at the end of
+        // the bitcode. If the bitcode file is old, the symbol table will be
+        // at the end instead and will not have been seen yet. In this case,
+        // just finish the parse now.
+        if (LazyStreamer && SeenValueSymbolTable) {
+          NextUnreadBit = Stream.GetCurrentBitNo();
+          return false;
+        }
+        break;
+      case naclbitc::USELIST_BLOCK_ID:
+        if (ParseUseLists())
+          return true;
+        break;
+      }
+      continue;
+
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+
+    // Read a record.
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default: break;  // Default behavior, ignore unknown content.
+    case naclbitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
+      if (Record.size() < 1)
+        return Error("Malformed MODULE_CODE_VERSION");
+      // Only version #0 and #1 are supported so far.
+      unsigned module_version = Record[0];
+      switch (module_version) {
+        default: return Error("Unknown bitstream version!");
+        case 0:
+          UseRelativeIDs = false;
+          break;
+        case 1:
+          UseRelativeIDs = true;
+          break;
+      }
+      break;
+    }
+    case naclbitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_TRIPLE record");
+
+      // @LOCALMOD-BEGIN
+      // This hack is needed in order to get Clang compiled binaries
+      // working with the Gold plugin, until PNaCl backend is introduced
+      // in lib/Target/PNaCl.
+      if (S == "le32-unknown-nacl")
+        S = "armv7-none-linux-gnueabi";
+      // @LOCALMOD-END
+      TheModule->setTargetTriple(S);
+      break;
+    }
+    case naclbitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_DATALAYOUT record");
+      TheModule->setDataLayout(S);
+      break;
+    }
+    case naclbitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_ASM record");
+      TheModule->setModuleInlineAsm(S);
+      break;
+    }
+    case naclbitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strchr x N]
+      // FIXME: Remove in 4.0.
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_DEPLIB record");
+      // Ignore value.
+      break;
+    }
+    case naclbitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_SECTIONNAME record");
+      SectionTable.push_back(S);
+      break;
+    }
+    case naclbitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_GCNAME record");
+      GCTable.push_back(S);
+      break;
+    }
+    // GLOBALVAR: [pointer type, isconst, initid,
+    //             linkage, alignment, section, visibility, threadlocal,
+    //             unnamed_addr]
+    case naclbitc::MODULE_CODE_GLOBALVAR: {
+      if (Record.size() < 6)
+        return Error("Invalid MODULE_CODE_GLOBALVAR record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty) return Error("Invalid MODULE_CODE_GLOBALVAR record");
+      if (!Ty->isPointerTy())
+        return Error("Global not a pointer type!");
+      unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
+      Ty = cast<PointerType>(Ty)->getElementType();
+
+      bool isConstant = Record[1];
+      GlobalValue::LinkageTypes Linkage = GetDecodedLinkage(Record[3]);
+      unsigned Alignment = (1 << Record[4]) >> 1;
+      std::string Section;
+      if (Record[5]) {
+        if (Record[5]-1 >= SectionTable.size())
+          return Error("Invalid section ID");
+        Section = SectionTable[Record[5]-1];
+      }
+      GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
+      if (Record.size() > 6)
+        Visibility = GetDecodedVisibility(Record[6]);
+
+      GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
+      if (Record.size() > 7)
+        TLM = GetDecodedThreadLocalMode(Record[7]);
+
+      bool UnnamedAddr = false;
+      if (Record.size() > 8)
+        UnnamedAddr = Record[8];
+
+      bool ExternallyInitialized = false;
+      if (Record.size() > 9)
+        ExternallyInitialized = Record[9];
+
+      GlobalVariable *NewGV =
+        new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
+                           TLM, AddressSpace, ExternallyInitialized);
+      NewGV->setAlignment(Alignment);
+      if (!Section.empty())
+        NewGV->setSection(Section);
+      NewGV->setVisibility(Visibility);
+      NewGV->setUnnamedAddr(UnnamedAddr);
+
+      ValueList.push_back(NewGV);
+
+      // Remember which value to use for the global initializer.
+      if (unsigned InitID = Record[2])
+        GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
+      break;
+    }
+    // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
+    //             alignment, section, visibility, gc, unnamed_addr]
+    case naclbitc::MODULE_CODE_FUNCTION: {
+      if (Record.size() < 8)
+        return Error("Invalid MODULE_CODE_FUNCTION record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty) return Error("Invalid MODULE_CODE_FUNCTION record");
+      if (!Ty->isPointerTy())
+        return Error("Function not a pointer type!");
+      FunctionType *FTy =
+        dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
+      if (!FTy)
+        return Error("Function not a pointer to function type!");
+
+      Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
+                                        "", TheModule);
+
+      Func->setCallingConv(static_cast<CallingConv::ID>(Record[1]));
+      bool isProto = Record[2];
+      Func->setLinkage(GetDecodedLinkage(Record[3]));
+      Func->setAttributes(getAttributes(Record[4]));
+
+      Func->setAlignment((1 << Record[5]) >> 1);
+      if (Record[6]) {
+        if (Record[6]-1 >= SectionTable.size())
+          return Error("Invalid section ID");
+        Func->setSection(SectionTable[Record[6]-1]);
+      }
+      Func->setVisibility(GetDecodedVisibility(Record[7]));
+      if (Record.size() > 8 && Record[8]) {
+        if (Record[8]-1 > GCTable.size())
+          return Error("Invalid GC ID");
+        Func->setGC(GCTable[Record[8]-1].c_str());
+      }
+      bool UnnamedAddr = false;
+      if (Record.size() > 9)
+        UnnamedAddr = Record[9];
+      Func->setUnnamedAddr(UnnamedAddr);
+      ValueList.push_back(Func);
+
+      // If this is a function with a body, remember the prototype we are
+      // creating now, so that we can match up the body with them later.
+      if (!isProto) {
+        FunctionsWithBodies.push_back(Func);
+        if (LazyStreamer) DeferredFunctionInfo[Func] = 0;
+      }
+      break;
+    }
+    // ALIAS: [alias type, aliasee val#, linkage]
+    // ALIAS: [alias type, aliasee val#, linkage, visibility]
+    case naclbitc::MODULE_CODE_ALIAS: {
+      if (Record.size() < 3)
+        return Error("Invalid MODULE_ALIAS record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty) return Error("Invalid MODULE_ALIAS record");
+      if (!Ty->isPointerTy())
+        return Error("Function not a pointer type!");
+
+      GlobalAlias *NewGA = new GlobalAlias(Ty, GetDecodedLinkage(Record[2]),
+                                           "", 0, TheModule);
+      // Old bitcode files didn't have visibility field.
+      if (Record.size() > 3)
+        NewGA->setVisibility(GetDecodedVisibility(Record[3]));
+      ValueList.push_back(NewGA);
+      AliasInits.push_back(std::make_pair(NewGA, Record[1]));
+      break;
+    }
+    /// MODULE_CODE_PURGEVALS: [numvals]
+    case naclbitc::MODULE_CODE_PURGEVALS:
+      // Trim down the value list to the specified size.
+      if (Record.size() < 1 || Record[0] > ValueList.size())
+        return Error("Invalid MODULE_PURGEVALS record");
+      ValueList.shrinkTo(Record[0]);
+      break;
+    }
+    Record.clear();
+  }
+}
+
+bool NaClBitcodeReader::ParseBitcodeInto(Module *M) {
+  TheModule = 0;
+
+  if (InitStream()) return true;
+
+  // Sniff for the signature.
+  if (Stream.Read(8) != 'B' ||
+      Stream.Read(8) != 'C' ||
+      Stream.Read(4) != 0x0 ||
+      Stream.Read(4) != 0xC ||
+      Stream.Read(4) != 0xE ||
+      Stream.Read(4) != 0xD)
+    return Error("Invalid bitcode signature");
+
+  // We expect a number of well-defined blocks, though we don't necessarily
+  // need to understand them all.
+  while (1) {
+    if (Stream.AtEndOfStream())
+      return false;
+
+    NaClBitstreamEntry Entry =
+      Stream.advance(NaClBitstreamCursor::AF_DontAutoprocessAbbrevs);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      Error("malformed module file");
+      return true;
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      case bitc::BLOCKINFO_BLOCK_ID:
+        if (Stream.ReadBlockInfoBlock())
+          return Error("Malformed BlockInfoBlock");
+        break;
+      case naclbitc::MODULE_BLOCK_ID:
+        // Reject multiple MODULE_BLOCK's in a single bitstream.
+        if (TheModule)
+          return Error("Multiple MODULE_BLOCKs in same stream");
+        TheModule = M;
+        if (ParseModule(false))
+          return true;
+        if (LazyStreamer) return false;
+        break;
+      default:
+        if (Stream.SkipBlock())
+          return Error("Malformed block record");
+        break;
+      }
+      continue;
+    case NaClBitstreamEntry::Record:
+      // There should be no records in the top-level of blocks.
+
+      // The ranlib in Xcode 4 will align archive members by appending newlines
+      // to the end of them. If this file size is a multiple of 4 but not 8, we
+      // have to read and ignore these final 4 bytes :-(
+      if (Stream.getAbbrevIDWidth() == 2 && Entry.ID == 2 &&
+          Stream.Read(6) == 2 && Stream.Read(24) == 0xa0a0a &&
+          Stream.AtEndOfStream())
+        return false;
+
+      return Error("Invalid record at top-level");
+    }
+  }
+}
+
+bool NaClBitcodeReader::ParseModuleTriple(std::string &Triple) {
+  if (Stream.EnterSubBlock(naclbitc::MODULE_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records for this module.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("malformed module block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default: break;  // Default behavior, ignore unknown content.
+    case naclbitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
+      std::string S;
+      if (ConvertToString(Record, 0, S))
+        return Error("Invalid MODULE_CODE_TRIPLE record");
+      Triple = S;
+      break;
+    }
+    }
+    Record.clear();
+  }
+}
+
+bool NaClBitcodeReader::ParseTriple(std::string &Triple) {
+  if (InitStream()) return true;
+
+  // Sniff for the signature.
+  if (Stream.Read(8) != 'B' ||
+      Stream.Read(8) != 'C' ||
+      Stream.Read(4) != 0x0 ||
+      Stream.Read(4) != 0xC ||
+      Stream.Read(4) != 0xE ||
+      Stream.Read(4) != 0xD)
+    return Error("Invalid bitcode signature");
+
+  // We expect a number of well-defined blocks, though we don't necessarily
+  // need to understand them all.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      Error("malformed module file");
+      return true;
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+
+    case NaClBitstreamEntry::SubBlock:
+      if (Entry.ID == naclbitc::MODULE_BLOCK_ID)
+        return ParseModuleTriple(Triple);
+
+      // Ignore other sub-blocks.
+      if (Stream.SkipBlock()) {
+        Error("malformed block record in AST file");
+        return true;
+      }
+      continue;
+
+    case NaClBitstreamEntry::Record:
+      Stream.skipRecord(Entry.ID);
+      continue;
+    }
+  }
+}
+
+/// ParseMetadataAttachment - Parse metadata attachments.
+bool NaClBitcodeReader::ParseMetadataAttachment() {
+  if (Stream.EnterSubBlock(naclbitc::METADATA_ATTACHMENT_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advanceSkippingSubblocks();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case NaClBitstreamEntry::Error:
+      return Error("malformed metadata block");
+    case NaClBitstreamEntry::EndBlock:
+      return false;
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a metadata attachment record.
+    Record.clear();
+    switch (Stream.readRecord(Entry.ID, Record)) {
+    default:  // Default behavior: ignore.
+      break;
+    case naclbitc::METADATA_ATTACHMENT: {
+      unsigned RecordLength = Record.size();
+      if (Record.empty() || (RecordLength - 1) % 2 == 1)
+        return Error ("Invalid METADATA_ATTACHMENT reader!");
+      Instruction *Inst = InstructionList[Record[0]];
+      for (unsigned i = 1; i != RecordLength; i = i+2) {
+        unsigned Kind = Record[i];
+        DenseMap<unsigned, unsigned>::iterator I =
+          MDKindMap.find(Kind);
+        if (I == MDKindMap.end())
+          return Error("Invalid metadata kind ID");
+        Value *Node = MDValueList.getValueFwdRef(Record[i+1]);
+        Inst->setMetadata(I->second, cast<MDNode>(Node));
+      }
+      break;
+    }
+    }
+  }
+}
+
+/// ParseFunctionBody - Lazily parse the specified function body block.
+bool NaClBitcodeReader::ParseFunctionBody(Function *F) {
+  if (Stream.EnterSubBlock(naclbitc::FUNCTION_BLOCK_ID))
+    return Error("Malformed block record");
+
+  InstructionList.clear();
+  unsigned ModuleValueListSize = ValueList.size();
+  unsigned ModuleMDValueListSize = MDValueList.size();
+
+  // Add all the function arguments to the value table.
+  for(Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
+    ValueList.push_back(I);
+
+  unsigned NextValueNo = ValueList.size();
+  BasicBlock *CurBB = 0;
+  unsigned CurBBNo = 0;
+
+  DebugLoc LastLoc;
+
+  // Read all the records.
+  SmallVector<uint64_t, 64> Record;
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance();
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      return Error("Bitcode error in function block");
+    case NaClBitstreamEntry::EndBlock:
+      goto OutOfRecordLoop;
+
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      default:  // Skip unknown content.
+        if (Stream.SkipBlock())
+          return Error("Malformed block record");
+        break;
+      case naclbitc::CONSTANTS_BLOCK_ID:
+        if (ParseConstants()) return true;
+        NextValueNo = ValueList.size();
+        break;
+      case naclbitc::VALUE_SYMTAB_BLOCK_ID:
+        if (ParseValueSymbolTable()) return true;
+        break;
+      case naclbitc::METADATA_ATTACHMENT_ID:
+        if (ParseMetadataAttachment()) return true;
+        break;
+      case naclbitc::METADATA_BLOCK_ID:
+        if (ParseMetadata()) return true;
+        break;
+      }
+      continue;
+
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    Instruction *I = 0;
+    unsigned BitCode = Stream.readRecord(Entry.ID, Record);
+    switch (BitCode) {
+    default: // Default behavior: reject
+      return Error("Unknown instruction");
+    case naclbitc::FUNC_CODE_DECLAREBLOCKS:     // DECLAREBLOCKS: [nblocks]
+      if (Record.size() < 1 || Record[0] == 0)
+        return Error("Invalid DECLAREBLOCKS record");
+      // Create all the basic blocks for the function.
+      FunctionBBs.resize(Record[0]);
+      for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
+        FunctionBBs[i] = BasicBlock::Create(Context, "", F);
+      CurBB = FunctionBBs[0];
+      continue;
+
+    case naclbitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
+      // This record indicates that the last instruction is at the same
+      // location as the previous instruction with a location.
+      I = 0;
+
+      // Get the last instruction emitted.
+      if (CurBB && !CurBB->empty())
+        I = &CurBB->back();
+      else if (CurBBNo && FunctionBBs[CurBBNo-1] &&
+               !FunctionBBs[CurBBNo-1]->empty())
+        I = &FunctionBBs[CurBBNo-1]->back();
+
+      if (I == 0) return Error("Invalid DEBUG_LOC_AGAIN record");
+      I->setDebugLoc(LastLoc);
+      I = 0;
+      continue;
+
+    case naclbitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
+      I = 0;     // Get the last instruction emitted.
+      if (CurBB && !CurBB->empty())
+        I = &CurBB->back();
+      else if (CurBBNo && FunctionBBs[CurBBNo-1] &&
+               !FunctionBBs[CurBBNo-1]->empty())
+        I = &FunctionBBs[CurBBNo-1]->back();
+      if (I == 0 || Record.size() < 4)
+        return Error("Invalid FUNC_CODE_DEBUG_LOC record");
+
+      unsigned Line = Record[0], Col = Record[1];
+      unsigned ScopeID = Record[2], IAID = Record[3];
+
+      MDNode *Scope = 0, *IA = 0;
+      if (ScopeID) Scope = cast<MDNode>(MDValueList.getValueFwdRef(ScopeID-1));
+      if (IAID)    IA = cast<MDNode>(MDValueList.getValueFwdRef(IAID-1));
+      LastLoc = DebugLoc::get(Line, Col, Scope, IA);
+      I->setDebugLoc(LastLoc);
+      I = 0;
+      continue;
+    }
+
+    case naclbitc::FUNC_CODE_INST_BINOP: {    // BINOP: [opval, ty, opval, opcode]
+      unsigned OpNum = 0;
+      Value *LHS, *RHS;
+      if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
+          popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
+          OpNum+1 > Record.size())
+        return Error("Invalid BINOP record");
+
+      int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
+      if (Opc == -1) return Error("Invalid BINOP record");
+      I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
+      InstructionList.push_back(I);
+      if (OpNum < Record.size()) {
+        if (Opc == Instruction::Add ||
+            Opc == Instruction::Sub ||
+            Opc == Instruction::Mul ||
+            Opc == Instruction::Shl) {
+          if (Record[OpNum] & (1 << naclbitc::OBO_NO_SIGNED_WRAP))
+            cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
+          if (Record[OpNum] & (1 << naclbitc::OBO_NO_UNSIGNED_WRAP))
+            cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
+        } else if (Opc == Instruction::SDiv ||
+                   Opc == Instruction::UDiv ||
+                   Opc == Instruction::LShr ||
+                   Opc == Instruction::AShr) {
+          if (Record[OpNum] & (1 << naclbitc::PEO_EXACT))
+            cast<BinaryOperator>(I)->setIsExact(true);
+        } else if (isa<FPMathOperator>(I)) {
+          FastMathFlags FMF;
+          if (0 != (Record[OpNum] & FastMathFlags::UnsafeAlgebra))
+            FMF.setUnsafeAlgebra();
+          if (0 != (Record[OpNum] & FastMathFlags::NoNaNs))
+            FMF.setNoNaNs();
+          if (0 != (Record[OpNum] & FastMathFlags::NoInfs))
+            FMF.setNoInfs();
+          if (0 != (Record[OpNum] & FastMathFlags::NoSignedZeros))
+            FMF.setNoSignedZeros();
+          if (0 != (Record[OpNum] & FastMathFlags::AllowReciprocal))
+            FMF.setAllowReciprocal();
+          if (FMF.any())
+            I->setFastMathFlags(FMF);
+        }
+
+      }
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, opty, destty, castopc]
+      unsigned OpNum = 0;
+      Value *Op;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
+          OpNum+2 != Record.size())
+        return Error("Invalid CAST record");
+
+      Type *ResTy = getTypeByID(Record[OpNum]);
+      int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
+      if (Opc == -1 || ResTy == 0)
+        return Error("Invalid CAST record");
+      I = CastInst::Create((Instruction::CastOps)Opc, Op, ResTy);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_INBOUNDS_GEP:
+    case naclbitc::FUNC_CODE_INST_GEP: { // GEP: [n x operands]
+      unsigned OpNum = 0;
+      Value *BasePtr;
+      if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
+        return Error("Invalid GEP record");
+
+      SmallVector<Value*, 16> GEPIdx;
+      while (OpNum != Record.size()) {
+        Value *Op;
+        if (getValueTypePair(Record, OpNum, NextValueNo, Op))
+          return Error("Invalid GEP record");
+        GEPIdx.push_back(Op);
+      }
+
+      I = GetElementPtrInst::Create(BasePtr, GEPIdx);
+      InstructionList.push_back(I);
+      if (BitCode == naclbitc::FUNC_CODE_INST_INBOUNDS_GEP)
+        cast<GetElementPtrInst>(I)->setIsInBounds(true);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_EXTRACTVAL: {
+                                       // EXTRACTVAL: [opty, opval, n x indices]
+      unsigned OpNum = 0;
+      Value *Agg;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
+        return Error("Invalid EXTRACTVAL record");
+
+      SmallVector<unsigned, 4> EXTRACTVALIdx;
+      for (unsigned RecSize = Record.size();
+           OpNum != RecSize; ++OpNum) {
+        uint64_t Index = Record[OpNum];
+        if ((unsigned)Index != Index)
+          return Error("Invalid EXTRACTVAL index");
+        EXTRACTVALIdx.push_back((unsigned)Index);
+      }
+
+      I = ExtractValueInst::Create(Agg, EXTRACTVALIdx);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_INSERTVAL: {
+                           // INSERTVAL: [opty, opval, opty, opval, n x indices]
+      unsigned OpNum = 0;
+      Value *Agg;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
+        return Error("Invalid INSERTVAL record");
+      Value *Val;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Val))
+        return Error("Invalid INSERTVAL record");
+
+      SmallVector<unsigned, 4> INSERTVALIdx;
+      for (unsigned RecSize = Record.size();
+           OpNum != RecSize; ++OpNum) {
+        uint64_t Index = Record[OpNum];
+        if ((unsigned)Index != Index)
+          return Error("Invalid INSERTVAL index");
+        INSERTVALIdx.push_back((unsigned)Index);
+      }
+
+      I = InsertValueInst::Create(Agg, Val, INSERTVALIdx);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_SELECT: { // SELECT: [opval, ty, opval, opval]
+      // obsolete form of select
+      // handles select i1 ... in old bitcode
+      unsigned OpNum = 0;
+      Value *TrueVal, *FalseVal, *Cond;
+      if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
+          popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
+          popValue(Record, OpNum, NextValueNo, Type::getInt1Ty(Context), Cond))
+        return Error("Invalid SELECT record");
+
+      I = SelectInst::Create(Cond, TrueVal, FalseVal);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_VSELECT: {// VSELECT: [ty,opval,opval,predty,pred]
+      // new form of select
+      // handles select i1 or select [N x i1]
+      unsigned OpNum = 0;
+      Value *TrueVal, *FalseVal, *Cond;
+      if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
+          popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
+          getValueTypePair(Record, OpNum, NextValueNo, Cond))
+        return Error("Invalid SELECT record");
+
+      // select condition can be either i1 or [N x i1]
+      if (VectorType* vector_type =
+          dyn_cast<VectorType>(Cond->getType())) {
+        // expect <n x i1>
+        if (vector_type->getElementType() != Type::getInt1Ty(Context))
+          return Error("Invalid SELECT condition type");
+      } else {
+        // expect i1
+        if (Cond->getType() != Type::getInt1Ty(Context))
+          return Error("Invalid SELECT condition type");
+      }
+
+      I = SelectInst::Create(Cond, TrueVal, FalseVal);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_EXTRACTELT: { // EXTRACTELT: [opty, opval, opval]
+      unsigned OpNum = 0;
+      Value *Vec, *Idx;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
+          popValue(Record, OpNum, NextValueNo, Type::getInt32Ty(Context), Idx))
+        return Error("Invalid EXTRACTELT record");
+      I = ExtractElementInst::Create(Vec, Idx);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_INSERTELT: { // INSERTELT: [ty, opval,opval,opval]
+      unsigned OpNum = 0;
+      Value *Vec, *Elt, *Idx;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
+          popValue(Record, OpNum, NextValueNo,
+                   cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
+          popValue(Record, OpNum, NextValueNo, Type::getInt32Ty(Context), Idx))
+        return Error("Invalid INSERTELT record");
+      I = InsertElementInst::Create(Vec, Elt, Idx);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_SHUFFLEVEC: {// SHUFFLEVEC: [opval,ty,opval,opval]
+      unsigned OpNum = 0;
+      Value *Vec1, *Vec2, *Mask;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Vec1) ||
+          popValue(Record, OpNum, NextValueNo, Vec1->getType(), Vec2))
+        return Error("Invalid SHUFFLEVEC record");
+
+      if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
+        return Error("Invalid SHUFFLEVEC record");
+      I = new ShuffleVectorInst(Vec1, Vec2, Mask);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_CMP:   // CMP: [opty, opval, opval, pred]
+      // Old form of ICmp/FCmp returning bool
+      // Existed to differentiate between icmp/fcmp and vicmp/vfcmp which were
+      // both legal on vectors but had different behaviour.
+    case naclbitc::FUNC_CODE_INST_CMP2: { // CMP2: [opty, opval, opval, pred]
+      // FCmp/ICmp returning bool or vector of bool
+
+      unsigned OpNum = 0;
+      Value *LHS, *RHS;
+      if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
+          popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
+          OpNum+1 != Record.size())
+        return Error("Invalid CMP record");
+
+      if (LHS->getType()->isFPOrFPVectorTy())
+        I = new FCmpInst((FCmpInst::Predicate)Record[OpNum], LHS, RHS);
+      else
+        I = new ICmpInst((ICmpInst::Predicate)Record[OpNum], LHS, RHS);
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_RET: // RET: [opty,opval<optional>]
+      {
+        unsigned Size = Record.size();
+        if (Size == 0) {
+          I = ReturnInst::Create(Context);
+          InstructionList.push_back(I);
+          break;
+        }
+
+        unsigned OpNum = 0;
+        Value *Op = NULL;
+        if (getValueTypePair(Record, OpNum, NextValueNo, Op))
+          return Error("Invalid RET record");
+        if (OpNum != Record.size())
+          return Error("Invalid RET record");
+
+        I = ReturnInst::Create(Context, Op);
+        InstructionList.push_back(I);
+        break;
+      }
+    case naclbitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
+      if (Record.size() != 1 && Record.size() != 3)
+        return Error("Invalid BR record");
+      BasicBlock *TrueDest = getBasicBlock(Record[0]);
+      if (TrueDest == 0)
+        return Error("Invalid BR record");
+
+      if (Record.size() == 1) {
+        I = BranchInst::Create(TrueDest);
+        InstructionList.push_back(I);
+      }
+      else {
+        BasicBlock *FalseDest = getBasicBlock(Record[1]);
+        Value *Cond = getValue(Record, 2, NextValueNo,
+                               Type::getInt1Ty(Context));
+        if (FalseDest == 0 || Cond == 0)
+          return Error("Invalid BR record");
+        I = BranchInst::Create(TrueDest, FalseDest, Cond);
+        InstructionList.push_back(I);
+      }
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
+      // Check magic
+      if ((Record[0] >> 16) == SWITCH_INST_MAGIC) {
+        // New SwitchInst format with case ranges.
+
+        Type *OpTy = getTypeByID(Record[1]);
+        unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
+
+        Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
+        BasicBlock *Default = getBasicBlock(Record[3]);
+        if (OpTy == 0 || Cond == 0 || Default == 0)
+          return Error("Invalid SWITCH record");
+
+        unsigned NumCases = Record[4];
+
+        SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
+        InstructionList.push_back(SI);
+
+        unsigned CurIdx = 5;
+        for (unsigned i = 0; i != NumCases; ++i) {
+          IntegersSubsetToBB CaseBuilder;
+          unsigned NumItems = Record[CurIdx++];
+          for (unsigned ci = 0; ci != NumItems; ++ci) {
+            bool isSingleNumber = Record[CurIdx++];
+
+            APInt Low;
+            unsigned ActiveWords = 1;
+            if (ValueBitWidth > 64)
+              ActiveWords = Record[CurIdx++];
+            Low = ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
+                                ValueBitWidth);
+            CurIdx += ActiveWords;
+
+            if (!isSingleNumber) {
+              ActiveWords = 1;
+              if (ValueBitWidth > 64)
+                ActiveWords = Record[CurIdx++];
+              APInt High =
+                  ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
+                                ValueBitWidth);
+
+              CaseBuilder.add(IntItem::fromType(OpTy, Low),
+                              IntItem::fromType(OpTy, High));
+              CurIdx += ActiveWords;
+            } else
+              CaseBuilder.add(IntItem::fromType(OpTy, Low));
+          }
+          BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
+          IntegersSubset Case = CaseBuilder.getCase();
+          SI->addCase(Case, DestBB);
+        }
+        uint16_t Hash = SI->hash();
+        if (Hash != (Record[0] & 0xFFFF))
+          return Error("Invalid SWITCH record");
+        I = SI;
+        break;
+      }
+
+      // Old SwitchInst format without case ranges.
+
+      if (Record.size() < 3 || (Record.size() & 1) == 0)
+        return Error("Invalid SWITCH record");
+      Type *OpTy = getTypeByID(Record[0]);
+      Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
+      BasicBlock *Default = getBasicBlock(Record[2]);
+      if (OpTy == 0 || Cond == 0 || Default == 0)
+        return Error("Invalid SWITCH record");
+      unsigned NumCases = (Record.size()-3)/2;
+      SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
+      InstructionList.push_back(SI);
+      for (unsigned i = 0, e = NumCases; i != e; ++i) {
+        ConstantInt *CaseVal =
+          dyn_cast_or_null<ConstantInt>(getFnValueByID(Record[3+i*2], OpTy));
+        BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
+        if (CaseVal == 0 || DestBB == 0) {
+          delete SI;
+          return Error("Invalid SWITCH record!");
+        }
+        SI->addCase(CaseVal, DestBB);
+      }
+      I = SI;
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
+      if (Record.size() < 2)
+        return Error("Invalid INDIRECTBR record");
+      Type *OpTy = getTypeByID(Record[0]);
+      Value *Address = getValue(Record, 1, NextValueNo, OpTy);
+      if (OpTy == 0 || Address == 0)
+        return Error("Invalid INDIRECTBR record");
+      unsigned NumDests = Record.size()-2;
+      IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
+      InstructionList.push_back(IBI);
+      for (unsigned i = 0, e = NumDests; i != e; ++i) {
+        if (BasicBlock *DestBB = getBasicBlock(Record[2+i])) {
+          IBI->addDestination(DestBB);
+        } else {
+          delete IBI;
+          return Error("Invalid INDIRECTBR record!");
+        }
+      }
+      I = IBI;
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_INVOKE: {
+      // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
+      if (Record.size() < 4) return Error("Invalid INVOKE record");
+      AttributeSet PAL = getAttributes(Record[0]);
+      unsigned CCInfo = Record[1];
+      BasicBlock *NormalBB = getBasicBlock(Record[2]);
+      BasicBlock *UnwindBB = getBasicBlock(Record[3]);
+
+      unsigned OpNum = 4;
+      Value *Callee;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
+        return Error("Invalid INVOKE record");
+
+      PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
+      FunctionType *FTy = !CalleeTy ? 0 :
+        dyn_cast<FunctionType>(CalleeTy->getElementType());
+
+      // Check that the right number of fixed parameters are here.
+      if (FTy == 0 || NormalBB == 0 || UnwindBB == 0 ||
+          Record.size() < OpNum+FTy->getNumParams())
+        return Error("Invalid INVOKE record");
+
+      SmallVector<Value*, 16> Ops;
+      for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
+        Ops.push_back(getValue(Record, OpNum, NextValueNo,
+                               FTy->getParamType(i)));
+        if (Ops.back() == 0) return Error("Invalid INVOKE record");
+      }
+
+      if (!FTy->isVarArg()) {
+        if (Record.size() != OpNum)
+          return Error("Invalid INVOKE record");
+      } else {
+        // Read type/value pairs for varargs params.
+        while (OpNum != Record.size()) {
+          Value *Op;
+          if (getValueTypePair(Record, OpNum, NextValueNo, Op))
+            return Error("Invalid INVOKE record");
+          Ops.push_back(Op);
+        }
+      }
+
+      I = InvokeInst::Create(Callee, NormalBB, UnwindBB, Ops);
+      InstructionList.push_back(I);
+      cast<InvokeInst>(I)->setCallingConv(
+        static_cast<CallingConv::ID>(CCInfo));
+      cast<InvokeInst>(I)->setAttributes(PAL);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
+      unsigned Idx = 0;
+      Value *Val = 0;
+      if (getValueTypePair(Record, Idx, NextValueNo, Val))
+        return Error("Invalid RESUME record");
+      I = ResumeInst::Create(Val);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
+      I = new UnreachableInst(Context);
+      InstructionList.push_back(I);
+      break;
+    case naclbitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
+      if (Record.size() < 1 || ((Record.size()-1)&1))
+        return Error("Invalid PHI record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty) return Error("Invalid PHI record");
+
+      PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
+      InstructionList.push_back(PN);
+
+      for (unsigned i = 0, e = Record.size()-1; i != e; i += 2) {
+        Value *V;
+        // With the new function encoding, it is possible that operands have
+        // negative IDs (for forward references).  Use a signed VBR
+        // representation to keep the encoding small.
+        if (UseRelativeIDs)
+          V = getValueSigned(Record, 1+i, NextValueNo, Ty);
+        else
+          V = getValue(Record, 1+i, NextValueNo, Ty);
+        BasicBlock *BB = getBasicBlock(Record[2+i]);
+        if (!V || !BB) return Error("Invalid PHI record");
+        PN->addIncoming(V, BB);
+      }
+      I = PN;
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_LANDINGPAD: {
+      // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
+      unsigned Idx = 0;
+      if (Record.size() < 4)
+        return Error("Invalid LANDINGPAD record");
+      Type *Ty = getTypeByID(Record[Idx++]);
+      if (!Ty) return Error("Invalid LANDINGPAD record");
+      Value *PersFn = 0;
+      if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
+        return Error("Invalid LANDINGPAD record");
+
+      bool IsCleanup = !!Record[Idx++];
+      unsigned NumClauses = Record[Idx++];
+      LandingPadInst *LP = LandingPadInst::Create(Ty, PersFn, NumClauses);
+      LP->setCleanup(IsCleanup);
+      for (unsigned J = 0; J != NumClauses; ++J) {
+        LandingPadInst::ClauseType CT =
+          LandingPadInst::ClauseType(Record[Idx++]); (void)CT;
+        Value *Val;
+
+        if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
+          delete LP;
+          return Error("Invalid LANDINGPAD record");
+        }
+
+        assert((CT != LandingPadInst::Catch ||
+                !isa<ArrayType>(Val->getType())) &&
+               "Catch clause has a invalid type!");
+        assert((CT != LandingPadInst::Filter ||
+                isa<ArrayType>(Val->getType())) &&
+               "Filter clause has invalid type!");
+        LP->addClause(Val);
+      }
+
+      I = LP;
+      InstructionList.push_back(I);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
+      if (Record.size() != 4)
+        return Error("Invalid ALLOCA record");
+      PointerType *Ty =
+        dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
+      Type *OpTy = getTypeByID(Record[1]);
+      Value *Size = getFnValueByID(Record[2], OpTy);
+      unsigned Align = Record[3];
+      if (!Ty || !Size) return Error("Invalid ALLOCA record");
+      I = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
+      unsigned OpNum = 0;
+      Value *Op;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
+          OpNum+2 != Record.size())
+        return Error("Invalid LOAD record");
+
+      I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_LOADATOMIC: {
+       // LOADATOMIC: [opty, op, align, vol, ordering, synchscope]
+      unsigned OpNum = 0;
+      Value *Op;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
+          OpNum+4 != Record.size())
+        return Error("Invalid LOADATOMIC record");
+
+
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
+      if (Ordering == NotAtomic || Ordering == Release ||
+          Ordering == AcquireRelease)
+        return Error("Invalid LOADATOMIC record");
+      if (Ordering != NotAtomic && Record[OpNum] == 0)
+        return Error("Invalid LOADATOMIC record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
+
+      I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1,
+                       Ordering, SynchScope);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_STORE: { // STORE2:[ptrty, ptr, val, align, vol]
+      unsigned OpNum = 0;
+      Value *Val, *Ptr;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
+          popValue(Record, OpNum, NextValueNo,
+                    cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
+          OpNum+2 != Record.size())
+        return Error("Invalid STORE record");
+
+      I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_STOREATOMIC: {
+      // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, synchscope]
+      unsigned OpNum = 0;
+      Value *Val, *Ptr;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
+          popValue(Record, OpNum, NextValueNo,
+                    cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
+          OpNum+4 != Record.size())
+        return Error("Invalid STOREATOMIC record");
+
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
+      if (Ordering == NotAtomic || Ordering == Acquire ||
+          Ordering == AcquireRelease)
+        return Error("Invalid STOREATOMIC record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
+      if (Ordering != NotAtomic && Record[OpNum] == 0)
+        return Error("Invalid STOREATOMIC record");
+
+      I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1,
+                        Ordering, SynchScope);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_CMPXCHG: {
+      // CMPXCHG:[ptrty, ptr, cmp, new, vol, ordering, synchscope]
+      unsigned OpNum = 0;
+      Value *Ptr, *Cmp, *New;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
+          popValue(Record, OpNum, NextValueNo,
+                    cast<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
+          popValue(Record, OpNum, NextValueNo,
+                    cast<PointerType>(Ptr->getType())->getElementType(), New) ||
+          OpNum+3 != Record.size())
+        return Error("Invalid CMPXCHG record");
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+1]);
+      if (Ordering == NotAtomic || Ordering == Unordered)
+        return Error("Invalid CMPXCHG record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
+      I = new AtomicCmpXchgInst(Ptr, Cmp, New, Ordering, SynchScope);
+      cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_ATOMICRMW: {
+      // ATOMICRMW:[ptrty, ptr, val, op, vol, ordering, synchscope]
+      unsigned OpNum = 0;
+      Value *Ptr, *Val;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
+          popValue(Record, OpNum, NextValueNo,
+                    cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
+          OpNum+4 != Record.size())
+        return Error("Invalid ATOMICRMW record");
+      AtomicRMWInst::BinOp Operation = GetDecodedRMWOperation(Record[OpNum]);
+      if (Operation < AtomicRMWInst::FIRST_BINOP ||
+          Operation > AtomicRMWInst::LAST_BINOP)
+        return Error("Invalid ATOMICRMW record");
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
+      if (Ordering == NotAtomic || Ordering == Unordered)
+        return Error("Invalid ATOMICRMW record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
+      I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
+      cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
+      if (2 != Record.size())
+        return Error("Invalid FENCE record");
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
+      if (Ordering == NotAtomic || Ordering == Unordered ||
+          Ordering == Monotonic)
+        return Error("Invalid FENCE record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
+      I = new FenceInst(Context, Ordering, SynchScope);
+      InstructionList.push_back(I);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_CALL: {
+      // CALL: [paramattrs, cc, fnty, fnid, arg0, arg1...]
+      if (Record.size() < 3)
+        return Error("Invalid CALL record");
+
+      AttributeSet PAL = getAttributes(Record[0]);
+      unsigned CCInfo = Record[1];
+
+      unsigned OpNum = 2;
+      Value *Callee;
+      if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
+        return Error("Invalid CALL record");
+
+      PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
+      FunctionType *FTy = 0;
+      if (OpTy) FTy = dyn_cast<FunctionType>(OpTy->getElementType());
+      if (!FTy || Record.size() < FTy->getNumParams()+OpNum)
+        return Error("Invalid CALL record");
+
+      SmallVector<Value*, 16> Args;
+      // Read the fixed params.
+      for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
+        if (FTy->getParamType(i)->isLabelTy())
+          Args.push_back(getBasicBlock(Record[OpNum]));
+        else
+          Args.push_back(getValue(Record, OpNum, NextValueNo,
+                                  FTy->getParamType(i)));
+        if (Args.back() == 0) return Error("Invalid CALL record");
+      }
+
+      // Read type/value pairs for varargs params.
+      if (!FTy->isVarArg()) {
+        if (OpNum != Record.size())
+          return Error("Invalid CALL record");
+      } else {
+        while (OpNum != Record.size()) {
+          Value *Op;
+          if (getValueTypePair(Record, OpNum, NextValueNo, Op))
+            return Error("Invalid CALL record");
+          Args.push_back(Op);
+        }
+      }
+
+      I = CallInst::Create(Callee, Args);
+      InstructionList.push_back(I);
+      cast<CallInst>(I)->setCallingConv(
+        static_cast<CallingConv::ID>(CCInfo>>1));
+      cast<CallInst>(I)->setTailCall(CCInfo & 1);
+      cast<CallInst>(I)->setAttributes(PAL);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
+      if (Record.size() < 3)
+        return Error("Invalid VAARG record");
+      Type *OpTy = getTypeByID(Record[0]);
+      Value *Op = getValue(Record, 1, NextValueNo, OpTy);
+      Type *ResTy = getTypeByID(Record[2]);
+      if (!OpTy || !Op || !ResTy)
+        return Error("Invalid VAARG record");
+      I = new VAArgInst(Op, ResTy);
+      InstructionList.push_back(I);
+      break;
+    }
+    }
+
+    // Add instruction to end of current BB.  If there is no current BB, reject
+    // this file.
+    if (CurBB == 0) {
+      delete I;
+      return Error("Invalid instruction with no BB");
+    }
+    CurBB->getInstList().push_back(I);
+
+    // If this was a terminator instruction, move to the next block.
+    if (isa<TerminatorInst>(I)) {
+      ++CurBBNo;
+      CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : 0;
+    }
+
+    // Non-void values get registered in the value table for future use.
+    if (I && !I->getType()->isVoidTy())
+      ValueList.AssignValue(I, NextValueNo++);
+  }
+
+OutOfRecordLoop:
+
+  // Check the function list for unresolved values.
+  if (Argument *A = dyn_cast<Argument>(ValueList.back())) {
+    if (A->getParent() == 0) {
+      // We found at least one unresolved value.  Nuke them all to avoid leaks.
+      for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
+        if ((A = dyn_cast<Argument>(ValueList[i])) && A->getParent() == 0) {
+          A->replaceAllUsesWith(UndefValue::get(A->getType()));
+          delete A;
+        }
+      }
+      return Error("Never resolved value found in function!");
+    }
+  }
+
+  // FIXME: Check for unresolved forward-declared metadata references
+  // and clean up leaks.
+
+  // See if anything took the address of blocks in this function.  If so,
+  // resolve them now.
+  DenseMap<Function*, std::vector<BlockAddrRefTy> >::iterator BAFRI =
+    BlockAddrFwdRefs.find(F);
+  if (BAFRI != BlockAddrFwdRefs.end()) {
+    std::vector<BlockAddrRefTy> &RefList = BAFRI->second;
+    for (unsigned i = 0, e = RefList.size(); i != e; ++i) {
+      unsigned BlockIdx = RefList[i].first;
+      if (BlockIdx >= FunctionBBs.size())
+        return Error("Invalid blockaddress block #");
+
+      GlobalVariable *FwdRef = RefList[i].second;
+      FwdRef->replaceAllUsesWith(BlockAddress::get(F, FunctionBBs[BlockIdx]));
+      FwdRef->eraseFromParent();
+    }
+
+    BlockAddrFwdRefs.erase(BAFRI);
+  }
+
+  // Trim the value list down to the size it was before we parsed this function.
+  ValueList.shrinkTo(ModuleValueListSize);
+  MDValueList.shrinkTo(ModuleMDValueListSize);
+  std::vector<BasicBlock*>().swap(FunctionBBs);
+  return false;
+}
+
+/// FindFunctionInStream - Find the function body in the bitcode stream
+bool NaClBitcodeReader::FindFunctionInStream(Function *F,
+       DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator) {
+  while (DeferredFunctionInfoIterator->second == 0) {
+    if (Stream.AtEndOfStream())
+      return Error("Could not find Function in stream");
+    // ParseModule will parse the next body in the stream and set its
+    // position in the DeferredFunctionInfo map.
+    if (ParseModule(true)) return true;
+  }
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// GVMaterializer implementation
+//===----------------------------------------------------------------------===//
+
+
+bool NaClBitcodeReader::isMaterializable(const GlobalValue *GV) const {
+  if (const Function *F = dyn_cast<Function>(GV)) {
+    return F->isDeclaration() &&
+      DeferredFunctionInfo.count(const_cast<Function*>(F));
+  }
+  return false;
+}
+
+bool NaClBitcodeReader::Materialize(GlobalValue *GV, std::string *ErrInfo) {
+  Function *F = dyn_cast<Function>(GV);
+  // If it's not a function or is already material, ignore the request.
+  if (!F || !F->isMaterializable()) return false;
+
+  DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
+  assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
+  // If its position is recorded as 0, its body is somewhere in the stream
+  // but we haven't seen it yet.
+  if (DFII->second == 0)
+    if (LazyStreamer && FindFunctionInStream(F, DFII)) return true;
+
+  // Move the bit stream to the saved position of the deferred function body.
+  Stream.JumpToBit(DFII->second);
+
+  if (ParseFunctionBody(F)) {
+    if (ErrInfo) *ErrInfo = ErrorString;
+    return true;
+  }
+
+  // Upgrade any old intrinsic calls in the function.
+  for (UpgradedIntrinsicMap::iterator I = UpgradedIntrinsics.begin(),
+       E = UpgradedIntrinsics.end(); I != E; ++I) {
+    if (I->first != I->second) {
+      for (Value::use_iterator UI = I->first->use_begin(),
+           UE = I->first->use_end(); UI != UE; ) {
+        if (CallInst* CI = dyn_cast<CallInst>(*UI++))
+          UpgradeIntrinsicCall(CI, I->second);
+      }
+    }
+  }
+
+  return false;
+}
+
+bool NaClBitcodeReader::isDematerializable(const GlobalValue *GV) const {
+  const Function *F = dyn_cast<Function>(GV);
+  if (!F || F->isDeclaration())
+    return false;
+  // @LOCALMOD-START
+  // Don't dematerialize functions with BBs which have their address taken;
+  // it will cause any referencing blockAddress constants to also be destroyed,
+  // but because they are GVs, they need to stay around until PassManager
+  // finalization.
+  for (Function::const_iterator BB = F->begin(); BB != F->end(); ++BB) {
+    if (BB->hasAddressTaken())
+      return false;
+  }
+  // @LOCALMOD-END
+  return DeferredFunctionInfo.count(const_cast<Function*>(F));
+}
+
+void NaClBitcodeReader::Dematerialize(GlobalValue *GV) {
+  Function *F = dyn_cast<Function>(GV);
+  // If this function isn't dematerializable, this is a noop.
+  if (!F || !isDematerializable(F))
+    return;
+
+  assert(DeferredFunctionInfo.count(F) && "No info to read function later?");
+
+  // Just forget the function body, we can remat it later.
+  F->deleteBody();
+}
+
+
+bool NaClBitcodeReader::MaterializeModule(Module *M, std::string *ErrInfo) {
+  assert(M == TheModule &&
+         "Can only Materialize the Module this NaClBitcodeReader is attached to.");
+  // Iterate over the module, deserializing any functions that are still on
+  // disk.
+  for (Module::iterator F = TheModule->begin(), E = TheModule->end();
+       F != E; ++F)
+    if (F->isMaterializable() &&
+        Materialize(F, ErrInfo))
+      return true;
+
+  // At this point, if there are any function bodies, the current bit is
+  // pointing to the END_BLOCK record after them. Now make sure the rest
+  // of the bits in the module have been read.
+  if (NextUnreadBit)
+    ParseModule(true);
+
+  // Upgrade any intrinsic calls that slipped through (should not happen!) and
+  // delete the old functions to clean up. We can't do this unless the entire
+  // module is materialized because there could always be another function body
+  // with calls to the old function.
+  for (std::vector<std::pair<Function*, Function*> >::iterator I =
+       UpgradedIntrinsics.begin(), E = UpgradedIntrinsics.end(); I != E; ++I) {
+    if (I->first != I->second) {
+      for (Value::use_iterator UI = I->first->use_begin(),
+           UE = I->first->use_end(); UI != UE; ) {
+        if (CallInst* CI = dyn_cast<CallInst>(*UI++))
+          UpgradeIntrinsicCall(CI, I->second);
+      }
+      if (!I->first->use_empty())
+        I->first->replaceAllUsesWith(I->second);
+      I->first->eraseFromParent();
+    }
+  }
+  std::vector<std::pair<Function*, Function*> >().swap(UpgradedIntrinsics);
+
+  return false;
+}
+
+bool NaClBitcodeReader::InitStream() {
+  if (LazyStreamer) return InitLazyStream();
+  return InitStreamFromBuffer();
+}
+
+bool NaClBitcodeReader::InitStreamFromBuffer() {
+  const unsigned char *BufPtr = (const unsigned char*)Buffer->getBufferStart();
+  const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
+
+  if (Buffer->getBufferSize() & 3) {
+    if (!isNaClRawBitcode(BufPtr, BufEnd) &&
+        !isNaClBitcodeWrapper(BufPtr, BufEnd))
+      return Error("Invalid bitcode signature");
+    else
+      return Error("Bitcode stream should be a multiple of 4 bytes in length");
+  }
+
+  // If we have a wrapper header, parse it and ignore the non-bc file contents.
+  // The magic number is 0x0B17C0DE stored in little endian.
+  if (isNaClBitcodeWrapper(BufPtr, BufEnd))
+    if (SkipNaClBitcodeWrapperHeader(BufPtr, BufEnd, true))
+      return Error("Invalid bitcode wrapper header");
+
+  StreamFile.reset(new NaClBitstreamReader(BufPtr, BufEnd));
+  Stream.init(*StreamFile);
+
+  return false;
+}
+
+bool NaClBitcodeReader::InitLazyStream() {
+  // Check and strip off the bitcode wrapper; NaClBitstreamReader expects
+  // never to see it.
+  StreamingMemoryObject *Bytes = new StreamingMemoryObject(LazyStreamer);
+  StreamFile.reset(new NaClBitstreamReader(Bytes));
+  Stream.init(*StreamFile);
+
+  unsigned char buf[16];
+  if (Bytes->readBytes(0, 16, buf, NULL) == -1)
+    return Error("Bitcode stream must be at least 16 bytes in length");
+
+  if (!isNaClBitcode(buf, buf + 16))
+    return Error("Invalid bitcode signature");
+
+  if (isNaClBitcodeWrapper(buf, buf + 4)) {
+    const unsigned char *bitcodeStart = buf;
+    const unsigned char *bitcodeEnd = buf + 16;
+    SkipNaClBitcodeWrapperHeader(bitcodeStart, bitcodeEnd, false);
+    Bytes->dropLeadingBytes(bitcodeStart - buf);
+    Bytes->setKnownObjectSize(bitcodeEnd - bitcodeStart);
+  }
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// External interface
+//===----------------------------------------------------------------------===//
+
+/// getNaClLazyBitcodeModule - lazy function-at-a-time loading from a file.
+///
+Module *llvm::getNaClLazyBitcodeModule(MemoryBuffer *Buffer,
+                                       LLVMContext& Context,
+                                       std::string *ErrMsg) {
+  Module *M = new Module(Buffer->getBufferIdentifier(), Context);
+  NaClBitcodeReader *R = new NaClBitcodeReader(Buffer, Context);
+  M->setMaterializer(R);
+  if (R->ParseBitcodeInto(M)) {
+    if (ErrMsg)
+      *ErrMsg = R->getErrorString();
+
+    delete M;  // Also deletes R.
+    return 0;
+  }
+  // Have the NaClBitcodeReader dtor delete 'Buffer'.
+  R->setBufferOwned(true);
+
+  R->materializeForwardReferencedFunctions();
+
+  M->convertMetadataToLibraryList(); // @LOCALMOD
+
+  return M;
+}
+
+
+Module *llvm::getNaClStreamedBitcodeModule(const std::string &name,
+                                           DataStreamer *streamer,
+                                           LLVMContext &Context,
+                                           std::string *ErrMsg) {
+  Module *M = new Module(name, Context);
+  NaClBitcodeReader *R = new NaClBitcodeReader(streamer, Context);
+  M->setMaterializer(R);
+  if (R->ParseBitcodeInto(M)) {
+    if (ErrMsg)
+      *ErrMsg = R->getErrorString();
+    delete M;  // Also deletes R.
+    return 0;
+  }
+  R->setBufferOwned(false); // no buffer to delete
+
+  R->materializeForwardReferencedFunctions();
+
+  M->convertMetadataToLibraryList(); // @LOCALMOD
+
+  return M;
+}
+
+/// NaClParseBitcodeFile - Read the specified bitcode file, returning the module.
+/// If an error occurs, return null and fill in *ErrMsg if non-null.
+Module *llvm::NaClParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,
+                                   std::string *ErrMsg){
+  Module *M = getNaClLazyBitcodeModule(Buffer, Context, ErrMsg);
+  if (!M) return 0;
+
+  // Don't let the NaClBitcodeReader dtor delete 'Buffer', regardless of whether
+  // there was an error.
+  static_cast<NaClBitcodeReader*>(M->getMaterializer())->setBufferOwned(false);
+
+  // Read in the entire module, and destroy the NaClBitcodeReader.
+  if (M->MaterializeAllPermanently(ErrMsg)) {
+    delete M;
+    return 0;
+  }
+
+  // TODO: Restore the use-lists to the in-memory state when the bitcode was
+  // written.  We must defer until the Module has been fully materialized.
+
+  return M;
+}
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
new file mode 100644
index 0000000000..f6e3e94841
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
@@ -0,0 +1,350 @@
+//===- NaClBitcodeReader.h ------------------------------------*- C++ -*-===//
+//     Internal NaClBitcodeReader implementation
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines the NaClBitcodeReader class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef NACL_BITCODE_READER_H
+#define NACL_BITCODE_READER_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Bitcode/NaCl/NaClBitstreamReader.h"
+#include "llvm/Bitcode/NaCl/NaClLLVMBitCodes.h"
+#include "llvm/GVMaterializer.h"
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/OperandTraits.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Support/ValueHandle.h"
+#include <vector>
+
+namespace llvm {
+  class MemoryBuffer;
+  class LLVMContext;
+
+//===----------------------------------------------------------------------===//
+//                          NaClBitcodeReaderValueList Class
+//===----------------------------------------------------------------------===//
+
+class NaClBitcodeReaderValueList {
+  std::vector<WeakVH> ValuePtrs;
+
+  /// ResolveConstants - As we resolve forward-referenced constants, we add
+  /// information about them to this vector.  This allows us to resolve them in
+  /// bulk instead of resolving each reference at a time.  See the code in
+  /// ResolveConstantForwardRefs for more information about this.
+  ///
+  /// The key of this vector is the placeholder constant, the value is the slot
+  /// number that holds the resolved value.
+  typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
+  ResolveConstantsTy ResolveConstants;
+  LLVMContext &Context;
+public:
+  NaClBitcodeReaderValueList(LLVMContext &C) : Context(C) {}
+  ~NaClBitcodeReaderValueList() {
+    assert(ResolveConstants.empty() && "Constants not resolved?");
+  }
+
+  // vector compatibility methods
+  unsigned size() const { return ValuePtrs.size(); }
+  void resize(unsigned N) { ValuePtrs.resize(N); }
+  void push_back(Value *V) {
+    ValuePtrs.push_back(V);
+  }
+
+  void clear() {
+    assert(ResolveConstants.empty() && "Constants not resolved?");
+    ValuePtrs.clear();
+  }
+
+  Value *operator[](unsigned i) const {
+    assert(i < ValuePtrs.size());
+    return ValuePtrs[i];
+  }
+
+  Value *back() const { return ValuePtrs.back(); }
+    void pop_back() { ValuePtrs.pop_back(); }
+  bool empty() const { return ValuePtrs.empty(); }
+  void shrinkTo(unsigned N) {
+    assert(N <= size() && "Invalid shrinkTo request!");
+    ValuePtrs.resize(N);
+  }
+
+  Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
+  Value *getValueFwdRef(unsigned Idx, Type *Ty);
+
+  void AssignValue(Value *V, unsigned Idx);
+
+  /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
+  /// resolves any forward references.
+  void ResolveConstantForwardRefs();
+};
+
+
+//===----------------------------------------------------------------------===//
+//                          NaClBitcodeReaderMDValueList Class
+//===----------------------------------------------------------------------===//
+
+class NaClBitcodeReaderMDValueList {
+  std::vector<WeakVH> MDValuePtrs;
+
+  LLVMContext &Context;
+public:
+  NaClBitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
+
+  // vector compatibility methods
+  unsigned size() const       { return MDValuePtrs.size(); }
+  void resize(unsigned N)     { MDValuePtrs.resize(N); }
+  void push_back(Value *V)    { MDValuePtrs.push_back(V);  }
+  void clear()                { MDValuePtrs.clear();  }
+  Value *back() const         { return MDValuePtrs.back(); }
+  void pop_back()             { MDValuePtrs.pop_back(); }
+  bool empty() const          { return MDValuePtrs.empty(); }
+
+  Value *operator[](unsigned i) const {
+    assert(i < MDValuePtrs.size());
+    return MDValuePtrs[i];
+  }
+
+  void shrinkTo(unsigned N) {
+    assert(N <= size() && "Invalid shrinkTo request!");
+    MDValuePtrs.resize(N);
+  }
+
+  Value *getValueFwdRef(unsigned Idx);
+  void AssignValue(Value *V, unsigned Idx);
+};
+
+class NaClBitcodeReader : public GVMaterializer {
+  LLVMContext &Context;
+  Module *TheModule;
+  MemoryBuffer *Buffer;
+  bool BufferOwned;
+  OwningPtr<NaClBitstreamReader> StreamFile;
+  NaClBitstreamCursor Stream;
+  DataStreamer *LazyStreamer;
+  uint64_t NextUnreadBit;
+  bool SeenValueSymbolTable;
+
+  const char *ErrorString;
+
+  std::vector<Type*> TypeList;
+  NaClBitcodeReaderValueList ValueList;
+  NaClBitcodeReaderMDValueList MDValueList;
+  SmallVector<Instruction *, 64> InstructionList;
+  SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
+
+  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
+  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
+
+  /// MAttributes - The set of attributes by index.  Index zero in the
+  /// file is for null, and is thus not represented here.  As such all indices
+  /// are off by one.
+  std::vector<AttributeSet> MAttributes;
+
+  /// \brief The set of attribute groups.
+  std::map<unsigned, AttributeSet> MAttributeGroups;
+
+  /// FunctionBBs - While parsing a function body, this is a list of the basic
+  /// blocks for the function.
+  std::vector<BasicBlock*> FunctionBBs;
+
+  // When reading the module header, this list is populated with functions that
+  // have bodies later in the file.
+  std::vector<Function*> FunctionsWithBodies;
+
+  // When intrinsic functions are encountered which require upgrading they are
+  // stored here with their replacement function.
+  typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
+  UpgradedIntrinsicMap UpgradedIntrinsics;
+
+  // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
+  DenseMap<unsigned, unsigned> MDKindMap;
+
+  // Several operations happen after the module header has been read, but
+  // before function bodies are processed. This keeps track of whether
+  // we've done this yet.
+  bool SeenFirstFunctionBody;
+
+  /// DeferredFunctionInfo - When function bodies are initially scanned, this
+  /// map contains info about where to find deferred function body in the
+  /// stream.
+  DenseMap<Function*, uint64_t> DeferredFunctionInfo;
+
+  /// BlockAddrFwdRefs - These are blockaddr references to basic blocks.  These
+  /// are resolved lazily when functions are loaded.
+  typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
+  DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
+
+  /// UseRelativeIDs - Indicates that we are using a new encoding for
+  /// instruction operands where most operands in the current
+  /// FUNCTION_BLOCK are encoded relative to the instruction number,
+  /// for a more compact encoding.  Some instruction operands are not
+  /// relative to the instruction ID: basic block numbers, and types.
+  /// Once the old style function blocks have been phased out, we would
+  /// not need this flag.
+  bool UseRelativeIDs;
+
+public:
+  explicit NaClBitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
+    : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
+      LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false), UseRelativeIDs(false) {
+  }
+  explicit NaClBitcodeReader(DataStreamer *streamer, LLVMContext &C)
+    : Context(C), TheModule(0), Buffer(0), BufferOwned(false),
+      LazyStreamer(streamer), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false), UseRelativeIDs(false) {
+  }
+  ~NaClBitcodeReader() {
+    FreeState();
+  }
+
+  void materializeForwardReferencedFunctions();
+
+  void FreeState();
+
+  /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
+  /// when the reader is destroyed.
+  void setBufferOwned(bool Owned) { BufferOwned = Owned; }
+
+  virtual bool isMaterializable(const GlobalValue *GV) const;
+  virtual bool isDematerializable(const GlobalValue *GV) const;
+  virtual bool Materialize(GlobalValue *GV, std::string *ErrInfo = 0);
+  virtual bool MaterializeModule(Module *M, std::string *ErrInfo = 0);
+  virtual void Dematerialize(GlobalValue *GV);
+
+  bool Error(const char *Str) {
+    ErrorString = Str;
+    return true;
+  }
+  const char *getErrorString() const { return ErrorString; }
+
+  /// @brief Main interface to parsing a bitcode buffer.
+  /// @returns true if an error occurred.
+  bool ParseBitcodeInto(Module *M);
+
+  /// @brief Cheap mechanism to just extract module triple
+  /// @returns true if an error occurred.
+  bool ParseTriple(std::string &Triple);
+
+  static uint64_t decodeSignRotatedValue(uint64_t V);
+
+private:
+  Type *getTypeByID(unsigned ID);
+  Value *getFnValueByID(unsigned ID, Type *Ty) {
+    if (Ty && Ty->isMetadataTy())
+      return MDValueList.getValueFwdRef(ID);
+    return ValueList.getValueFwdRef(ID, Ty);
+  }
+  BasicBlock *getBasicBlock(unsigned ID) const {
+    if (ID >= FunctionBBs.size()) return 0; // Invalid ID
+    return FunctionBBs[ID];
+  }
+  AttributeSet getAttributes(unsigned i) const {
+    if (i-1 < MAttributes.size())
+      return MAttributes[i-1];
+    return AttributeSet();
+  }
+
+  /// getValueTypePair - Read a value/type pair out of the specified record from
+  /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
+  /// Return true on failure.
+  bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
+                        unsigned InstNum, Value *&ResVal) {
+    if (Slot == Record.size()) return true;
+    unsigned ValNo = (unsigned)Record[Slot++];
+    // Adjust the ValNo, if it was encoded relative to the InstNum.
+    if (UseRelativeIDs)
+      ValNo = InstNum - ValNo;
+    if (ValNo < InstNum) {
+      // If this is not a forward reference, just return the value we already
+      // have.
+      ResVal = getFnValueByID(ValNo, 0);
+      return ResVal == 0;
+    } else if (Slot == Record.size()) {
+      return true;
+    }
+
+    unsigned TypeNo = (unsigned)Record[Slot++];
+    ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
+    return ResVal == 0;
+  }
+
+  /// popValue - Read a value out of the specified record from slot 'Slot'.
+  /// Increment Slot past the number of slots used by the value in the record.
+  /// Return true if there is an error.
+  bool popValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
+                unsigned InstNum, Type *Ty, Value *&ResVal) {
+    if (getValue(Record, Slot, InstNum, Ty, ResVal))
+      return true;
+    // All values currently take a single record slot.
+    ++Slot;
+    return false;
+  }
+
+  /// getValue -- Like popValue, but does not increment the Slot number.
+  bool getValue(SmallVector<uint64_t, 64> &Record, unsigned Slot,
+                unsigned InstNum, Type *Ty, Value *&ResVal) {
+    ResVal = getValue(Record, Slot, InstNum, Ty);
+    return ResVal == 0;
+  }
+
+  /// getValue -- Version of getValue that returns ResVal directly,
+  /// or 0 if there is an error.
+  Value *getValue(SmallVector<uint64_t, 64> &Record, unsigned Slot,
+                  unsigned InstNum, Type *Ty) {
+    if (Slot == Record.size()) return 0;
+    unsigned ValNo = (unsigned)Record[Slot];
+    // Adjust the ValNo, if it was encoded relative to the InstNum.
+    if (UseRelativeIDs)
+      ValNo = InstNum - ValNo;
+    return getFnValueByID(ValNo, Ty);
+  }
+
+  /// getValueSigned -- Like getValue, but decodes signed VBRs.
+  Value *getValueSigned(SmallVector<uint64_t, 64> &Record, unsigned Slot,
+                        unsigned InstNum, Type *Ty) {
+    if (Slot == Record.size()) return 0;
+    unsigned ValNo = (unsigned)decodeSignRotatedValue(Record[Slot]);
+    // Adjust the ValNo, if it was encoded relative to the InstNum.
+    if (UseRelativeIDs)
+      ValNo = InstNum - ValNo;
+    return getFnValueByID(ValNo, Ty);
+  }
+
+  bool ParseModule(bool Resume);
+  bool ParseAttributeBlock();
+  bool ParseAttributeGroupBlock();
+  bool ParseTypeTable();
+  bool ParseTypeTableBody();
+
+  bool ParseValueSymbolTable();
+  bool ParseConstants();
+  bool RememberAndSkipFunctionBody();
+  bool ParseFunctionBody(Function *F);
+  bool GlobalCleanup();
+  bool ResolveGlobalAndAliasInits();
+  bool ParseMetadata();
+  bool ParseMetadataAttachment();
+  bool ParseModuleTriple(std::string &Triple);
+  bool ParseUseLists();
+  bool InitStream();
+  bool InitStreamFromBuffer();
+  bool InitLazyStream();
+  bool FindFunctionInStream(Function *F,
+         DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator);
+};
+
+} // End llvm namespace
+
+#endif
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitstreamReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitstreamReader.cpp
new file mode 100644
index 0000000000..ab8f1a5c6d
--- /dev/null
+++ b/lib/Bitcode/NaCl/Reader/NaClBitstreamReader.cpp
@@ -0,0 +1,373 @@
+//===- NaClBitstreamReader.cpp --------------------------------------------===//
+//     NaClBitstreamReader implementation
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/NaCl/NaClBitstreamReader.h"
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//  NaClBitstreamCursor implementation
+//===----------------------------------------------------------------------===//
+
+void NaClBitstreamCursor::operator=(const NaClBitstreamCursor &RHS) {
+  freeState();
+
+  BitStream = RHS.BitStream;
+  NextChar = RHS.NextChar;
+  CurWord = RHS.CurWord;
+  BitsInCurWord = RHS.BitsInCurWord;
+  CurCodeSize = RHS.CurCodeSize;
+
+  // Copy abbreviations, and bump ref counts.
+  CurAbbrevs = RHS.CurAbbrevs;
+  for (size_t i = 0, e = CurAbbrevs.size(); i != e; ++i)
+    CurAbbrevs[i]->addRef();
+
+  // Copy block scope and bump ref counts.
+  BlockScope = RHS.BlockScope;
+  for (size_t S = 0, e = BlockScope.size(); S != e; ++S) {
+    std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
+    for (size_t i = 0, e = Abbrevs.size(); i != e; ++i)
+      Abbrevs[i]->addRef();
+  }
+}
+
+void NaClBitstreamCursor::freeState() {
+  // Free all the Abbrevs.
+  for (size_t i = 0, e = CurAbbrevs.size(); i != e; ++i)
+    CurAbbrevs[i]->dropRef();
+  CurAbbrevs.clear();
+
+  // Free all the Abbrevs in the block scope.
+  for (size_t S = 0, e = BlockScope.size(); S != e; ++S) {
+    std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
+    for (size_t i = 0, e = Abbrevs.size(); i != e; ++i)
+      Abbrevs[i]->dropRef();
+  }
+  BlockScope.clear();
+}
+
+/// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
+/// the block, and return true if the block has an error.
+bool NaClBitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
+  // Save the current block's state on BlockScope.
+  BlockScope.push_back(Block(CurCodeSize));
+  BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+
+  // Add the abbrevs specific to this block to the CurAbbrevs list.
+  if (const NaClBitstreamReader::BlockInfo *Info =
+      BitStream->getBlockInfo(BlockID)) {
+    for (size_t i = 0, e = Info->Abbrevs.size(); i != e; ++i) {
+      CurAbbrevs.push_back(Info->Abbrevs[i]);
+      CurAbbrevs.back()->addRef();
+    }
+  }
+
+  // Get the codesize of this block.
+  CurCodeSize = ReadVBR(bitc::CodeLenWidth);
+  SkipToFourByteBoundary();
+  unsigned NumWords = Read(bitc::BlockSizeWidth);
+  if (NumWordsP) *NumWordsP = NumWords;
+
+  // Validate that this block is sane.
+  if (CurCodeSize == 0 || AtEndOfStream())
+    return true;
+
+  return false;
+}
+
+void NaClBitstreamCursor::readAbbreviatedLiteral(
+    const BitCodeAbbrevOp &Op,
+    SmallVectorImpl<uint64_t> &Vals) {
+  assert(Op.isLiteral() && "Not a literal");
+  // If the abbrev specifies the literal value to use, use it.
+  Vals.push_back(Op.getLiteralValue());
+}
+
+void NaClBitstreamCursor::readAbbreviatedField(
+    const BitCodeAbbrevOp &Op,
+    SmallVectorImpl<uint64_t> &Vals) {
+  assert(!Op.isLiteral() && "Use ReadAbbreviatedLiteral for literals!");
+
+  // Decode the value as we are commanded.
+  switch (Op.getEncoding()) {
+  case BitCodeAbbrevOp::Array:
+  case BitCodeAbbrevOp::Blob:
+    assert(0 && "Should not reach here");
+  case BitCodeAbbrevOp::Fixed:
+    Vals.push_back(Read((unsigned)Op.getEncodingData()));
+    break;
+  case BitCodeAbbrevOp::VBR:
+    Vals.push_back(ReadVBR64((unsigned)Op.getEncodingData()));
+    break;
+  case BitCodeAbbrevOp::Char6:
+    Vals.push_back(BitCodeAbbrevOp::DecodeChar6(Read(6)));
+    break;
+  }
+}
+
+void NaClBitstreamCursor::skipAbbreviatedField(const BitCodeAbbrevOp &Op) {
+  assert(!Op.isLiteral() && "Use ReadAbbreviatedLiteral for literals!");
+
+  // Decode the value as we are commanded.
+  switch (Op.getEncoding()) {
+  case BitCodeAbbrevOp::Array:
+  case BitCodeAbbrevOp::Blob:
+    assert(0 && "Should not reach here");
+  case BitCodeAbbrevOp::Fixed:
+    (void)Read((unsigned)Op.getEncodingData());
+    break;
+  case BitCodeAbbrevOp::VBR:
+    (void)ReadVBR64((unsigned)Op.getEncodingData());
+    break;
+  case BitCodeAbbrevOp::Char6:
+    (void)Read(6);
+    break;
+  }
+}
+
+
+
+/// skipRecord - Read the current record and discard it.
+void NaClBitstreamCursor::skipRecord(unsigned AbbrevID) {
+  // Skip unabbreviated records by reading past their entries.
+  if (AbbrevID == bitc::UNABBREV_RECORD) {
+    unsigned Code = ReadVBR(6);
+    (void)Code;
+    unsigned NumElts = ReadVBR(6);
+    for (unsigned i = 0; i != NumElts; ++i)
+      (void)ReadVBR64(6);
+    return;
+  }
+
+  const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+
+  for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
+    const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+    if (Op.isLiteral())
+      continue;
+
+    if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
+        Op.getEncoding() != BitCodeAbbrevOp::Blob) {
+      skipAbbreviatedField(Op);
+      continue;
+    }
+
+    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+      // Array case.  Read the number of elements as a vbr6.
+      unsigned NumElts = ReadVBR(6);
+
+      // Get the element encoding.
+      assert(i+2 == e && "array op not second to last?");
+      const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+
+      // Read all the elements.
+      for (; NumElts; --NumElts)
+        skipAbbreviatedField(EltEnc);
+      continue;
+    }
+
+    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+    // Blob case.  Read the number of bytes as a vbr6.
+    unsigned NumElts = ReadVBR(6);
+    SkipToFourByteBoundary();  // 32-bit alignment
+
+    // Figure out where the end of this blob will be including tail padding.
+    size_t NewEnd = GetCurrentBitNo()+((NumElts+3)&~3)*8;
+
+    // If this would read off the end of the bitcode file, just set the
+    // record to empty and return.
+    if (!canSkipToPos(NewEnd/8)) {
+      NextChar = BitStream->getBitcodeBytes().getExtent();
+      break;
+    }
+
+    // Skip over the blob.
+    JumpToBit(NewEnd);
+  }
+}
+
+unsigned NaClBitstreamCursor::readRecord(unsigned AbbrevID,
+                                         SmallVectorImpl<uint64_t> &Vals,
+                                         StringRef *Blob) {
+  if (AbbrevID == bitc::UNABBREV_RECORD) {
+    unsigned Code = ReadVBR(6);
+    unsigned NumElts = ReadVBR(6);
+    for (unsigned i = 0; i != NumElts; ++i)
+      Vals.push_back(ReadVBR64(6));
+    return Code;
+  }
+
+  const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+
+  for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
+    const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+    if (Op.isLiteral()) {
+      readAbbreviatedLiteral(Op, Vals);
+      continue;
+    }
+
+    if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
+        Op.getEncoding() != BitCodeAbbrevOp::Blob) {
+      readAbbreviatedField(Op, Vals);
+      continue;
+    }
+
+    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+      // Array case.  Read the number of elements as a vbr6.
+      unsigned NumElts = ReadVBR(6);
+
+      // Get the element encoding.
+      assert(i+2 == e && "array op not second to last?");
+      const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+
+      // Read all the elements.
+      for (; NumElts; --NumElts)
+        readAbbreviatedField(EltEnc, Vals);
+      continue;
+    }
+
+    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+    // Blob case.  Read the number of bytes as a vbr6.
+    unsigned NumElts = ReadVBR(6);
+    SkipToFourByteBoundary();  // 32-bit alignment
+
+    // Figure out where the end of this blob will be including tail padding.
+    size_t CurBitPos = GetCurrentBitNo();
+    size_t NewEnd = CurBitPos+((NumElts+3)&~3)*8;
+
+    // If this would read off the end of the bitcode file, just set the
+    // record to empty and return.
+    if (!canSkipToPos(NewEnd/8)) {
+      Vals.append(NumElts, 0);
+      NextChar = BitStream->getBitcodeBytes().getExtent();
+      break;
+    }
+
+    // Otherwise, inform the streamer that we need these bytes in memory.
+    const char *Ptr = (const char*)
+      BitStream->getBitcodeBytes().getPointer(CurBitPos/8, NumElts);
+
+    // If we can return a reference to the data, do so to avoid copying it.
+    if (Blob) {
+      *Blob = StringRef(Ptr, NumElts);
+    } else {
+      // Otherwise, unpack into Vals with zero extension.
+      for (; NumElts; --NumElts)
+        Vals.push_back((unsigned char)*Ptr++);
+    }
+    // Skip over tail padding.
+    JumpToBit(NewEnd);
+  }
+
+  unsigned Code = (unsigned)Vals[0];
+  Vals.erase(Vals.begin());
+  return Code;
+}
+
+
+void NaClBitstreamCursor::ReadAbbrevRecord() {
+  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
+  unsigned NumOpInfo = ReadVBR(5);
+  for (unsigned i = 0; i != NumOpInfo; ++i) {
+    bool IsLiteral = Read(1) ? true : false;
+    if (IsLiteral) {
+      Abbv->Add(BitCodeAbbrevOp(ReadVBR64(8)));
+      continue;
+    }
+
+    BitCodeAbbrevOp::Encoding E = (BitCodeAbbrevOp::Encoding)Read(3);
+    if (BitCodeAbbrevOp::hasEncodingData(E)) {
+      unsigned Data = ReadVBR64(5);
+
+      // As a special case, handle fixed(0) (i.e., a fixed field with zero bits)
+      // and vbr(0) as a literal zero.  This is decoded the same way, and avoids
+      // a slow path in Read() to have to handle reading zero bits.
+      if ((E == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
+          Data == 0) {
+        Abbv->Add(BitCodeAbbrevOp(0));
+        continue;
+      }
+      
+      Abbv->Add(BitCodeAbbrevOp(E, Data));
+    } else
+      Abbv->Add(BitCodeAbbrevOp(E));
+  }
+  CurAbbrevs.push_back(Abbv);
+}
+
+bool NaClBitstreamCursor::ReadBlockInfoBlock() {
+  // If this is the second stream to get to the block info block, skip it.
+  if (BitStream->hasBlockInfoRecords())
+    return SkipBlock();
+
+  if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return true;
+
+  SmallVector<uint64_t, 64> Record;
+  NaClBitstreamReader::BlockInfo *CurBlockInfo = 0;
+
+  // Read all the records for this module.
+  while (1) {
+    NaClBitstreamEntry Entry = advanceSkippingSubblocks(AF_DontAutoprocessAbbrevs);
+
+    switch (Entry.Kind) {
+    case llvm::NaClBitstreamEntry::SubBlock: // Handled for us already.
+    case llvm::NaClBitstreamEntry::Error:
+      return true;
+    case llvm::NaClBitstreamEntry::EndBlock:
+      return false;
+    case llvm::NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read abbrev records, associate them with CurBID.
+    if (Entry.ID == bitc::DEFINE_ABBREV) {
+      if (!CurBlockInfo) return true;
+      ReadAbbrevRecord();
+
+      // ReadAbbrevRecord installs the abbrev in CurAbbrevs.  Move it to the
+      // appropriate BlockInfo.
+      BitCodeAbbrev *Abbv = CurAbbrevs.back();
+      CurAbbrevs.pop_back();
+      CurBlockInfo->Abbrevs.push_back(Abbv);
+      continue;
+    }
+
+    // Read a record.
+    Record.clear();
+    switch (readRecord(Entry.ID, Record)) {
+      default: break;  // Default behavior, ignore unknown content.
+      case bitc::BLOCKINFO_CODE_SETBID:
+        if (Record.size() < 1) return true;
+        CurBlockInfo = &BitStream->getOrCreateBlockInfo((unsigned)Record[0]);
+        break;
+      case bitc::BLOCKINFO_CODE_BLOCKNAME: {
+        if (!CurBlockInfo) return true;
+        if (BitStream->isIgnoringBlockInfoNames()) break;  // Ignore name.
+        std::string Name;
+        for (unsigned i = 0, e = Record.size(); i != e; ++i)
+          Name += (char)Record[i];
+        CurBlockInfo->Name = Name;
+        break;
+      }
+      case bitc::BLOCKINFO_CODE_SETRECORDNAME: {
+        if (!CurBlockInfo) return true;
+        if (BitStream->isIgnoringBlockInfoNames()) break;  // Ignore name.
+        std::string Name;
+        for (unsigned i = 1, e = Record.size(); i != e; ++i)
+          Name += (char)Record[i];
+        CurBlockInfo->RecordNames.push_back(std::make_pair((unsigned)Record[0],
+                                                           Name));
+        break;
+      }
+    }
+  }
+}
diff --git a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
index 1cadd02450..edaaadf681 100644
--- a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
+++ b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
@@ -15,7 +15,7 @@
 #include "NaClValueEnumerator.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Bitcode/NaCl/NaClBitstreamWriter.h"
-#include "llvm/Bitcode/LLVMBitCodes.h"
+#include "llvm/Bitcode/NaCl/NaClLLVMBitCodes.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InlineAsm.h"
@@ -63,18 +63,18 @@ enum {
 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
   switch (Opcode) {
   default: llvm_unreachable("Unknown cast instruction!");
-  case Instruction::Trunc   : return bitc::CAST_TRUNC;
-  case Instruction::ZExt    : return bitc::CAST_ZEXT;
-  case Instruction::SExt    : return bitc::CAST_SEXT;
-  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
-  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
-  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
-  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
-  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
-  case Instruction::FPExt   : return bitc::CAST_FPEXT;
-  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
-  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
-  case Instruction::BitCast : return bitc::CAST_BITCAST;
+  case Instruction::Trunc   : return naclbitc::CAST_TRUNC;
+  case Instruction::ZExt    : return naclbitc::CAST_ZEXT;
+  case Instruction::SExt    : return naclbitc::CAST_SEXT;
+  case Instruction::FPToUI  : return naclbitc::CAST_FPTOUI;
+  case Instruction::FPToSI  : return naclbitc::CAST_FPTOSI;
+  case Instruction::UIToFP  : return naclbitc::CAST_UITOFP;
+  case Instruction::SIToFP  : return naclbitc::CAST_SITOFP;
+  case Instruction::FPTrunc : return naclbitc::CAST_FPTRUNC;
+  case Instruction::FPExt   : return naclbitc::CAST_FPEXT;
+  case Instruction::PtrToInt: return naclbitc::CAST_PTRTOINT;
+  case Instruction::IntToPtr: return naclbitc::CAST_INTTOPTR;
+  case Instruction::BitCast : return naclbitc::CAST_BITCAST;
   }
 }
 
@@ -82,60 +82,60 @@ static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
   switch (Opcode) {
   default: llvm_unreachable("Unknown binary instruction!");
   case Instruction::Add:
-  case Instruction::FAdd: return bitc::BINOP_ADD;
+  case Instruction::FAdd: return naclbitc::BINOP_ADD;
   case Instruction::Sub:
-  case Instruction::FSub: return bitc::BINOP_SUB;
+  case Instruction::FSub: return naclbitc::BINOP_SUB;
   case Instruction::Mul:
-  case Instruction::FMul: return bitc::BINOP_MUL;
-  case Instruction::UDiv: return bitc::BINOP_UDIV;
+  case Instruction::FMul: return naclbitc::BINOP_MUL;
+  case Instruction::UDiv: return naclbitc::BINOP_UDIV;
   case Instruction::FDiv:
-  case Instruction::SDiv: return bitc::BINOP_SDIV;
-  case Instruction::URem: return bitc::BINOP_UREM;
+  case Instruction::SDiv: return naclbitc::BINOP_SDIV;
+  case Instruction::URem: return naclbitc::BINOP_UREM;
   case Instruction::FRem:
-  case Instruction::SRem: return bitc::BINOP_SREM;
-  case Instruction::Shl:  return bitc::BINOP_SHL;
-  case Instruction::LShr: return bitc::BINOP_LSHR;
-  case Instruction::AShr: return bitc::BINOP_ASHR;
-  case Instruction::And:  return bitc::BINOP_AND;
-  case Instruction::Or:   return bitc::BINOP_OR;
-  case Instruction::Xor:  return bitc::BINOP_XOR;
+  case Instruction::SRem: return naclbitc::BINOP_SREM;
+  case Instruction::Shl:  return naclbitc::BINOP_SHL;
+  case Instruction::LShr: return naclbitc::BINOP_LSHR;
+  case Instruction::AShr: return naclbitc::BINOP_ASHR;
+  case Instruction::And:  return naclbitc::BINOP_AND;
+  case Instruction::Or:   return naclbitc::BINOP_OR;
+  case Instruction::Xor:  return naclbitc::BINOP_XOR;
   }
 }
 
 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
   switch (Op) {
   default: llvm_unreachable("Unknown RMW operation!");
-  case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
-  case AtomicRMWInst::Add: return bitc::RMW_ADD;
-  case AtomicRMWInst::Sub: return bitc::RMW_SUB;
-  case AtomicRMWInst::And: return bitc::RMW_AND;
-  case AtomicRMWInst::Nand: return bitc::RMW_NAND;
-  case AtomicRMWInst::Or: return bitc::RMW_OR;
-  case AtomicRMWInst::Xor: return bitc::RMW_XOR;
-  case AtomicRMWInst::Max: return bitc::RMW_MAX;
-  case AtomicRMWInst::Min: return bitc::RMW_MIN;
-  case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
-  case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
+  case AtomicRMWInst::Xchg: return naclbitc::RMW_XCHG;
+  case AtomicRMWInst::Add: return naclbitc::RMW_ADD;
+  case AtomicRMWInst::Sub: return naclbitc::RMW_SUB;
+  case AtomicRMWInst::And: return naclbitc::RMW_AND;
+  case AtomicRMWInst::Nand: return naclbitc::RMW_NAND;
+  case AtomicRMWInst::Or: return naclbitc::RMW_OR;
+  case AtomicRMWInst::Xor: return naclbitc::RMW_XOR;
+  case AtomicRMWInst::Max: return naclbitc::RMW_MAX;
+  case AtomicRMWInst::Min: return naclbitc::RMW_MIN;
+  case AtomicRMWInst::UMax: return naclbitc::RMW_UMAX;
+  case AtomicRMWInst::UMin: return naclbitc::RMW_UMIN;
   }
 }
 
 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
   switch (Ordering) {
-  case NotAtomic: return bitc::ORDERING_NOTATOMIC;
-  case Unordered: return bitc::ORDERING_UNORDERED;
-  case Monotonic: return bitc::ORDERING_MONOTONIC;
-  case Acquire: return bitc::ORDERING_ACQUIRE;
-  case Release: return bitc::ORDERING_RELEASE;
-  case AcquireRelease: return bitc::ORDERING_ACQREL;
-  case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
+  case NotAtomic: return naclbitc::ORDERING_NOTATOMIC;
+  case Unordered: return naclbitc::ORDERING_UNORDERED;
+  case Monotonic: return naclbitc::ORDERING_MONOTONIC;
+  case Acquire: return naclbitc::ORDERING_ACQUIRE;
+  case Release: return naclbitc::ORDERING_RELEASE;
+  case AcquireRelease: return naclbitc::ORDERING_ACQREL;
+  case SequentiallyConsistent: return naclbitc::ORDERING_SEQCST;
   }
   llvm_unreachable("Invalid ordering");
 }
 
 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
   switch (SynchScope) {
-  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
-  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
+  case SingleThread: return naclbitc::SYNCHSCOPE_SINGLETHREAD;
+  case CrossThread: return naclbitc::SYNCHSCOPE_CROSSTHREAD;
   }
   llvm_unreachable("Invalid synch scope");
 }
@@ -160,7 +160,7 @@ static void WriteAttributeGroupTable(const NaClValueEnumerator &VE,
   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
   if (AttrGrps.empty()) return;
 
-  Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
+  Stream.EnterSubblock(naclbitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
@@ -195,7 +195,7 @@ static void WriteAttributeGroupTable(const NaClValueEnumerator &VE,
         }
       }
 
-      Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
+      Stream.EmitRecord(naclbitc::PARAMATTR_GRP_CODE_ENTRY, Record);
       Record.clear();
     }
   }
@@ -208,7 +208,7 @@ static void WriteAttributeTable(const NaClValueEnumerator &VE,
   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
   if (Attrs.empty()) return;
 
-  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
+  Stream.EnterSubblock(naclbitc::PARAMATTR_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
@@ -216,7 +216,7 @@ static void WriteAttributeTable(const NaClValueEnumerator &VE,
     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 
-    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
+    Stream.EmitRecord(naclbitc::PARAMATTR_CODE_ENTRY, Record);
     Record.clear();
   }
 
@@ -228,21 +228,21 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
                            NaClBitstreamWriter &Stream) {
   const NaClValueEnumerator::TypeList &TypeList = VE.getTypes();
 
-  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
+  Stream.EnterSubblock(naclbitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
   SmallVector<uint64_t, 64> TypeVals;
 
   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 
   // Abbrev for TYPE_CODE_POINTER.
   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_POINTER));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 
   // Abbrev for TYPE_CODE_FUNCTION.
   Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_FUNCTION));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
@@ -251,7 +251,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
 
   // Abbrev for TYPE_CODE_STRUCT_ANON.
   Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_STRUCT_ANON));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
@@ -260,14 +260,14 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
 
   // Abbrev for TYPE_CODE_STRUCT_NAME.
   Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_STRUCT_NAME));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 
   // Abbrev for TYPE_CODE_STRUCT_NAMED.
   Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_STRUCT_NAMED));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
@@ -276,7 +276,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
 
   // Abbrev for TYPE_CODE_ARRAY.
   Abbv = new BitCodeAbbrev();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
+  Abbv->Add(BitCodeAbbrevOp(naclbitc::TYPE_CODE_ARRAY));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 
@@ -284,7 +284,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
 
   // Emit an entry count so the reader can reserve space.
   TypeVals.push_back(TypeList.size());
-  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
+  Stream.EmitRecord(naclbitc::TYPE_CODE_NUMENTRY, TypeVals);
   TypeVals.clear();
 
   // Loop over all of the types, emitting each in turn.
@@ -295,25 +295,25 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
 
     switch (T->getTypeID()) {
     default: llvm_unreachable("Unknown type!");
-    case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
-    case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
-    case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
-    case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
-    case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
-    case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
-    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
-    case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
-    case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
-    case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
+    case Type::VoidTyID:      Code = naclbitc::TYPE_CODE_VOID;      break;
+    case Type::HalfTyID:      Code = naclbitc::TYPE_CODE_HALF;      break;
+    case Type::FloatTyID:     Code = naclbitc::TYPE_CODE_FLOAT;     break;
+    case Type::DoubleTyID:    Code = naclbitc::TYPE_CODE_DOUBLE;    break;
+    case Type::X86_FP80TyID:  Code = naclbitc::TYPE_CODE_X86_FP80;  break;
+    case Type::FP128TyID:     Code = naclbitc::TYPE_CODE_FP128;     break;
+    case Type::PPC_FP128TyID: Code = naclbitc::TYPE_CODE_PPC_FP128; break;
+    case Type::LabelTyID:     Code = naclbitc::TYPE_CODE_LABEL;     break;
+    case Type::MetadataTyID:  Code = naclbitc::TYPE_CODE_METADATA;  break;
+    case Type::X86_MMXTyID:   Code = naclbitc::TYPE_CODE_X86_MMX;   break;
     case Type::IntegerTyID:
       // INTEGER: [width]
-      Code = bitc::TYPE_CODE_INTEGER;
+      Code = naclbitc::TYPE_CODE_INTEGER;
       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
       break;
     case Type::PointerTyID: {
       PointerType *PTy = cast<PointerType>(T);
       // POINTER: [pointee type, address space]
-      Code = bitc::TYPE_CODE_POINTER;
+      Code = naclbitc::TYPE_CODE_POINTER;
       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
       unsigned AddressSpace = PTy->getAddressSpace();
       TypeVals.push_back(AddressSpace);
@@ -323,7 +323,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
     case Type::FunctionTyID: {
       FunctionType *FT = cast<FunctionType>(T);
       // FUNCTION: [isvararg, retty, paramty x N]
-      Code = bitc::TYPE_CODE_FUNCTION;
+      Code = naclbitc::TYPE_CODE_FUNCTION;
       TypeVals.push_back(FT->isVarArg());
       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
@@ -341,19 +341,19 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
         TypeVals.push_back(VE.getTypeID(*I));
 
       if (ST->isLiteral()) {
-        Code = bitc::TYPE_CODE_STRUCT_ANON;
+        Code = naclbitc::TYPE_CODE_STRUCT_ANON;
         AbbrevToUse = StructAnonAbbrev;
       } else {
         if (ST->isOpaque()) {
-          Code = bitc::TYPE_CODE_OPAQUE;
+          Code = naclbitc::TYPE_CODE_OPAQUE;
         } else {
-          Code = bitc::TYPE_CODE_STRUCT_NAMED;
+          Code = naclbitc::TYPE_CODE_STRUCT_NAMED;
           AbbrevToUse = StructNamedAbbrev;
         }
 
         // Emit the name if it is present.
         if (!ST->getName().empty())
-          WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
+          WriteStringRecord(naclbitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
                             StructNameAbbrev, Stream);
       }
       break;
@@ -361,7 +361,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
     case Type::ArrayTyID: {
       ArrayType *AT = cast<ArrayType>(T);
       // ARRAY: [numelts, eltty]
-      Code = bitc::TYPE_CODE_ARRAY;
+      Code = naclbitc::TYPE_CODE_ARRAY;
       TypeVals.push_back(AT->getNumElements());
       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
       AbbrevToUse = ArrayAbbrev;
@@ -370,7 +370,7 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
     case Type::VectorTyID: {
       VectorType *VT = cast<VectorType>(T);
       // VECTOR [numelts, eltty]
-      Code = bitc::TYPE_CODE_VECTOR;
+      Code = naclbitc::TYPE_CODE_VECTOR;
       TypeVals.push_back(VT->getNumElements());
       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
       break;
@@ -433,13 +433,13 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
                             NaClBitstreamWriter &Stream) {
   // Emit various pieces of data attached to a module.
   if (!M->getTargetTriple().empty())
-    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
+    WriteStringRecord(naclbitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
                       0/*TODO*/, Stream);
   if (!M->getDataLayout().empty())
-    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
+    WriteStringRecord(naclbitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
                       0/*TODO*/, Stream);
   if (!M->getModuleInlineAsm().empty())
-    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
+    WriteStringRecord(naclbitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
                       0/*TODO*/, Stream);
 
   // Emit information about sections and GC, computing how many there are. Also
@@ -456,7 +456,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
       // Give section names unique ID's.
       unsigned &Entry = SectionMap[GV->getSection()];
       if (!Entry) {
-        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
+        WriteStringRecord(naclbitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
                           0/*TODO*/, Stream);
         Entry = SectionMap.size();
       }
@@ -468,7 +468,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
       // Give section names unique ID's.
       unsigned &Entry = SectionMap[F->getSection()];
       if (!Entry) {
-        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
+        WriteStringRecord(naclbitc::MODULE_CODE_SECTIONNAME, F->getSection(),
                           0/*TODO*/, Stream);
         Entry = SectionMap.size();
       }
@@ -477,7 +477,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
       // Same for GC names.
       unsigned &Entry = GCMap[F->getGC()];
       if (!Entry) {
-        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
+        WriteStringRecord(naclbitc::MODULE_CODE_GCNAME, F->getGC(),
                           0/*TODO*/, Stream);
         Entry = GCMap.size();
       }
@@ -489,7 +489,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
   if (!M->global_empty()) {
     // Add an abbrev for common globals with no visibility or thread localness.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::MODULE_CODE_GLOBALVAR));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
                               Log2_32_Ceil(MaxGlobalType+1)));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
@@ -538,7 +538,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
       AbbrevToUse = SimpleGVarAbbrev;
     }
 
-    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
+    Stream.EmitRecord(naclbitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
     Vals.clear();
   }
 
@@ -558,7 +558,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
     Vals.push_back(F->hasUnnamedAddr());
 
     unsigned AbbrevToUse = 0;
-    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
+    Stream.EmitRecord(naclbitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
     Vals.clear();
   }
 
@@ -571,7 +571,7 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
     Vals.push_back(getEncodedLinkage(AI));
     Vals.push_back(getEncodedVisibility(AI));
     unsigned AbbrevToUse = 0;
-    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
+    Stream.EmitRecord(naclbitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
     Vals.clear();
   }
 }
@@ -582,13 +582,13 @@ static uint64_t GetOptimizationFlags(const Value *V) {
   if (const OverflowingBinaryOperator *OBO =
         dyn_cast<OverflowingBinaryOperator>(V)) {
     if (OBO->hasNoSignedWrap())
-      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
+      Flags |= 1 << naclbitc::OBO_NO_SIGNED_WRAP;
     if (OBO->hasNoUnsignedWrap())
-      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
+      Flags |= 1 << naclbitc::OBO_NO_UNSIGNED_WRAP;
   } else if (const PossiblyExactOperator *PEO =
                dyn_cast<PossiblyExactOperator>(V)) {
     if (PEO->isExact())
-      Flags |= 1 << bitc::PEO_EXACT;
+      Flags |= 1 << naclbitc::PEO_EXACT;
   } else if (const FPMathOperator *FPMO =
              dyn_cast<const FPMathOperator>(V)) {
     if (FPMO->hasUnsafeAlgebra())
@@ -619,8 +619,8 @@ static void WriteMDNode(const MDNode *N,
       Record.push_back(0);
     }
   }
-  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
-                                           bitc::METADATA_NODE;
+  unsigned MDCode = N->isFunctionLocal() ? naclbitc::METADATA_FN_NODE :
+                                           naclbitc::METADATA_NODE;
   Stream.EmitRecord(MDCode, Record, 0);
   Record.clear();
 }
@@ -637,18 +637,18 @@ static void WriteModuleMetadata(const Module *M,
     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
       if (!N->isFunctionLocal() || !N->getFunction()) {
         if (!StartedMetadataBlock) {
-          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
+          Stream.EnterSubblock(naclbitc::METADATA_BLOCK_ID, 3);
           StartedMetadataBlock = true;
         }
         WriteMDNode(N, VE, Stream, Record);
       }
     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
       if (!StartedMetadataBlock)  {
-        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
+        Stream.EnterSubblock(naclbitc::METADATA_BLOCK_ID, 3);
 
         // Abbrev for METADATA_STRING.
         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
+        Abbv->Add(BitCodeAbbrevOp(naclbitc::METADATA_STRING));
         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
         MDSAbbrev = Stream.EmitAbbrev(Abbv);
@@ -659,7 +659,7 @@ static void WriteModuleMetadata(const Module *M,
       Record.append(MDS->begin(), MDS->end());
 
       // Emit the finished record.
-      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
+      Stream.EmitRecord(naclbitc::METADATA_STRING, Record, MDSAbbrev);
       Record.clear();
     }
   }
@@ -669,7 +669,7 @@ static void WriteModuleMetadata(const Module *M,
        E = M->named_metadata_end(); I != E; ++I) {
     const NamedMDNode *NMD = I;
     if (!StartedMetadataBlock)  {
-      Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
+      Stream.EnterSubblock(naclbitc::METADATA_BLOCK_ID, 3);
       StartedMetadataBlock = true;
     }
 
@@ -677,13 +677,13 @@ static void WriteModuleMetadata(const Module *M,
     StringRef Str = NMD->getName();
     for (unsigned i = 0, e = Str.size(); i != e; ++i)
       Record.push_back(Str[i]);
-    Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
+    Stream.EmitRecord(naclbitc::METADATA_NAME, Record, 0/*TODO*/);
     Record.clear();
 
     // Write named metadata operands.
     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
       Record.push_back(VE.getValueID(NMD->getOperand(i)));
-    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
+    Stream.EmitRecord(naclbitc::METADATA_NAMED_NODE, Record, 0);
     Record.clear();
   }
 
@@ -701,7 +701,7 @@ static void WriteFunctionLocalMetadata(const Function &F,
     if (const MDNode *N = Vals[i])
       if (N->isFunctionLocal() && N->getFunction() == &F) {
         if (!StartedMetadataBlock) {
-          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
+          Stream.EnterSubblock(naclbitc::METADATA_BLOCK_ID, 3);
           StartedMetadataBlock = true;
         }
         WriteMDNode(N, VE, Stream, Record);
@@ -714,7 +714,7 @@ static void WriteFunctionLocalMetadata(const Function &F,
 static void WriteMetadataAttachment(const Function &F,
                                     const NaClValueEnumerator &VE,
                                     NaClBitstreamWriter &Stream) {
-  Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
+  Stream.EnterSubblock(naclbitc::METADATA_ATTACHMENT_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
 
@@ -737,7 +737,7 @@ static void WriteMetadataAttachment(const Function &F,
         Record.push_back(MDs[i].first);
         Record.push_back(VE.getValueID(MDs[i].second));
       }
-      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
+      Stream.EmitRecord(naclbitc::METADATA_ATTACHMENT, Record, 0);
       Record.clear();
     }
 
@@ -754,14 +754,14 @@ static void WriteModuleMetadataStore(const Module *M, NaClBitstreamWriter &Strea
 
   if (Names.empty()) return;
 
-  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
+  Stream.EnterSubblock(naclbitc::METADATA_BLOCK_ID, 3);
 
   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
     Record.push_back(MDKindID);
     StringRef KName = Names[MDKindID];
     Record.append(KName.begin(), KName.end());
 
-    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
+    Stream.EmitRecord(naclbitc::METADATA_KIND, Record, 0);
     Record.clear();
   }
 
@@ -782,7 +782,7 @@ static void EmitAPInt(SmallVectorImpl<uint64_t> &Vals,
   if (Val.getBitWidth() <= 64) {
     uint64_t V = Val.getSExtValue();
     emitSignedInt64(Vals, V);
-    Code = bitc::CST_CODE_INTEGER;
+    Code = naclbitc::CST_CODE_INTEGER;
     AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
   } else {
     // Wide integers, > 64 bits in size.
@@ -799,7 +799,7 @@ static void EmitAPInt(SmallVectorImpl<uint64_t> &Vals,
     for (unsigned i = 0; i != NWords; ++i) {
       emitSignedInt64(Vals, RawWords[i]);
     }
-    Code = bitc::CST_CODE_WIDE_INTEGER;
+    Code = naclbitc::CST_CODE_WIDE_INTEGER;
   }
 }
 
@@ -808,7 +808,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
                            NaClBitstreamWriter &Stream, bool isGlobal) {
   if (FirstVal == LastVal) return;
 
-  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
+  Stream.EnterSubblock(naclbitc::CONSTANTS_BLOCK_ID, 4);
 
   unsigned AggregateAbbrev = 0;
   unsigned String8Abbrev = 0;
@@ -818,26 +818,26 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
   if (isGlobal) {
     // Abbrev for CST_CODE_AGGREGATE.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_AGGREGATE));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 
     // Abbrev for CST_CODE_STRING.
     Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_STRING));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
     String8Abbrev = Stream.EmitAbbrev(Abbv);
     // Abbrev for CST_CODE_CSTRING.
     Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_CSTRING));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
     CString7Abbrev = Stream.EmitAbbrev(Abbv);
     // Abbrev for CST_CODE_CSTRING.
     Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_CSTRING));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
     CString6Abbrev = Stream.EmitAbbrev(Abbv);
@@ -853,7 +853,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
     if (V->getType() != LastTy) {
       LastTy = V->getType();
       Record.push_back(VE.getTypeID(LastTy));
-      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
+      Stream.EmitRecord(naclbitc::CST_CODE_SETTYPE, Record,
                         CONSTANTS_SETTYPE_ABBREV);
       Record.clear();
     }
@@ -874,7 +874,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       Record.push_back(ConstraintStr.size());
       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
         Record.push_back(ConstraintStr[i]);
-      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
+      Stream.EmitRecord(naclbitc::CST_CODE_INLINEASM, Record);
       Record.clear();
       continue;
     }
@@ -882,13 +882,13 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
     unsigned Code = -1U;
     unsigned AbbrevToUse = 0;
     if (C->isNullValue()) {
-      Code = bitc::CST_CODE_NULL;
+      Code = naclbitc::CST_CODE_NULL;
     } else if (isa<UndefValue>(C)) {
-      Code = bitc::CST_CODE_UNDEF;
+      Code = naclbitc::CST_CODE_UNDEF;
     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
       EmitAPInt(Record, Code, AbbrevToUse, IV->getValue());
     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
-      Code = bitc::CST_CODE_FLOAT;
+      Code = naclbitc::CST_CODE_FLOAT;
       Type *Ty = CFP->getType();
       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
@@ -914,14 +914,14 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       unsigned NumElts = Str->getNumElements();
       // If this is a null-terminated string, use the denser CSTRING encoding.
       if (Str->isCString()) {
-        Code = bitc::CST_CODE_CSTRING;
+        Code = naclbitc::CST_CODE_CSTRING;
         --NumElts;  // Don't encode the null, which isn't allowed by char6.
       } else {
-        Code = bitc::CST_CODE_STRING;
+        Code = naclbitc::CST_CODE_STRING;
         AbbrevToUse = String8Abbrev;
       }
-      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
-      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
+      bool isCStr7 = Code == naclbitc::CST_CODE_CSTRING;
+      bool isCStrChar6 = Code == naclbitc::CST_CODE_CSTRING;
       for (unsigned i = 0; i != NumElts; ++i) {
         unsigned char V = Str->getElementAsInteger(i);
         Record.push_back(V);
@@ -936,7 +936,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
         AbbrevToUse = CString7Abbrev;
     } else if (const ConstantDataSequential *CDS =
                   dyn_cast<ConstantDataSequential>(C)) {
-      Code = bitc::CST_CODE_DATA;
+      Code = naclbitc::CST_CODE_DATA;
       Type *EltTy = CDS->getType()->getElementType();
       if (isa<IntegerType>(EltTy)) {
         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
@@ -957,7 +957,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       }
     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
                isa<ConstantVector>(C)) {
-      Code = bitc::CST_CODE_AGGREGATE;
+      Code = naclbitc::CST_CODE_AGGREGATE;
       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
         Record.push_back(VE.getValueID(C->getOperand(i)));
       AbbrevToUse = AggregateAbbrev;
@@ -965,14 +965,14 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       switch (CE->getOpcode()) {
       default:
         if (Instruction::isCast(CE->getOpcode())) {
-          Code = bitc::CST_CODE_CE_CAST;
+          Code = naclbitc::CST_CODE_CE_CAST;
           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
           Record.push_back(VE.getValueID(C->getOperand(0)));
           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
         } else {
           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
-          Code = bitc::CST_CODE_CE_BINOP;
+          Code = naclbitc::CST_CODE_CE_BINOP;
           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
           Record.push_back(VE.getValueID(C->getOperand(0)));
           Record.push_back(VE.getValueID(C->getOperand(1)));
@@ -982,28 +982,28 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
         }
         break;
       case Instruction::GetElementPtr:
-        Code = bitc::CST_CODE_CE_GEP;
+        Code = naclbitc::CST_CODE_CE_GEP;
         if (cast<GEPOperator>(C)->isInBounds())
-          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
+          Code = naclbitc::CST_CODE_CE_INBOUNDS_GEP;
         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
           Record.push_back(VE.getValueID(C->getOperand(i)));
         }
         break;
       case Instruction::Select:
-        Code = bitc::CST_CODE_CE_SELECT;
+        Code = naclbitc::CST_CODE_CE_SELECT;
         Record.push_back(VE.getValueID(C->getOperand(0)));
         Record.push_back(VE.getValueID(C->getOperand(1)));
         Record.push_back(VE.getValueID(C->getOperand(2)));
         break;
       case Instruction::ExtractElement:
-        Code = bitc::CST_CODE_CE_EXTRACTELT;
+        Code = naclbitc::CST_CODE_CE_EXTRACTELT;
         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
         Record.push_back(VE.getValueID(C->getOperand(0)));
         Record.push_back(VE.getValueID(C->getOperand(1)));
         break;
       case Instruction::InsertElement:
-        Code = bitc::CST_CODE_CE_INSERTELT;
+        Code = naclbitc::CST_CODE_CE_INSERTELT;
         Record.push_back(VE.getValueID(C->getOperand(0)));
         Record.push_back(VE.getValueID(C->getOperand(1)));
         Record.push_back(VE.getValueID(C->getOperand(2)));
@@ -1014,9 +1014,9 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
         // then the shuffle is widening or truncating the input vectors, and
         // the argument type must also be encoded.
         if (C->getType() == C->getOperand(0)->getType()) {
-          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
+          Code = naclbitc::CST_CODE_CE_SHUFFLEVEC;
         } else {
-          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
+          Code = naclbitc::CST_CODE_CE_SHUFVEC_EX;
           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
         }
         Record.push_back(VE.getValueID(C->getOperand(0)));
@@ -1025,7 +1025,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
         break;
       case Instruction::ICmp:
       case Instruction::FCmp:
-        Code = bitc::CST_CODE_CE_CMP;
+        Code = naclbitc::CST_CODE_CE_CMP;
         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
         Record.push_back(VE.getValueID(C->getOperand(0)));
         Record.push_back(VE.getValueID(C->getOperand(1)));
@@ -1033,7 +1033,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
         break;
       }
     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
-      Code = bitc::CST_CODE_BLOCKADDRESS;
+      Code = naclbitc::CST_CODE_BLOCKADDRESS;
       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
       Record.push_back(VE.getValueID(BA->getFunction()));
       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
@@ -1119,14 +1119,14 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
   switch (I.getOpcode()) {
   default:
     if (Instruction::isCast(I.getOpcode())) {
-      Code = bitc::FUNC_CODE_INST_CAST;
+      Code = naclbitc::FUNC_CODE_INST_CAST;
       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
       Vals.push_back(VE.getTypeID(I.getType()));
       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
     } else {
       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
-      Code = bitc::FUNC_CODE_INST_BINOP;
+      Code = naclbitc::FUNC_CODE_INST_BINOP;
       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
       pushValue(I.getOperand(1), InstID, Vals, VE);
@@ -1141,14 +1141,14 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
 
   case Instruction::GetElementPtr:
-    Code = bitc::FUNC_CODE_INST_GEP;
+    Code = naclbitc::FUNC_CODE_INST_GEP;
     if (cast<GEPOperator>(&I)->isInBounds())
-      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
+      Code = naclbitc::FUNC_CODE_INST_INBOUNDS_GEP;
     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
     break;
   case Instruction::ExtractValue: {
-    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
+    Code = naclbitc::FUNC_CODE_INST_EXTRACTVAL;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
@@ -1156,7 +1156,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   }
   case Instruction::InsertValue: {
-    Code = bitc::FUNC_CODE_INST_INSERTVAL;
+    Code = naclbitc::FUNC_CODE_INST_INSERTVAL;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
@@ -1165,24 +1165,24 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   }
   case Instruction::Select:
-    Code = bitc::FUNC_CODE_INST_VSELECT;
+    Code = naclbitc::FUNC_CODE_INST_VSELECT;
     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
     pushValue(I.getOperand(2), InstID, Vals, VE);
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     break;
   case Instruction::ExtractElement:
-    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
+    Code = naclbitc::FUNC_CODE_INST_EXTRACTELT;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     pushValue(I.getOperand(1), InstID, Vals, VE);
     break;
   case Instruction::InsertElement:
-    Code = bitc::FUNC_CODE_INST_INSERTELT;
+    Code = naclbitc::FUNC_CODE_INST_INSERTELT;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     pushValue(I.getOperand(1), InstID, Vals, VE);
     pushValue(I.getOperand(2), InstID, Vals, VE);
     break;
   case Instruction::ShuffleVector:
-    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
+    Code = naclbitc::FUNC_CODE_INST_SHUFFLEVEC;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     pushValue(I.getOperand(1), InstID, Vals, VE);
     pushValue(I.getOperand(2), InstID, Vals, VE);
@@ -1190,7 +1190,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
   case Instruction::ICmp:
   case Instruction::FCmp:
     // compare returning Int1Ty or vector of Int1Ty
-    Code = bitc::FUNC_CODE_INST_CMP2;
+    Code = naclbitc::FUNC_CODE_INST_CMP2;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     pushValue(I.getOperand(1), InstID, Vals, VE);
     Vals.push_back(cast<CmpInst>(I).getPredicate());
@@ -1198,7 +1198,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
 
   case Instruction::Ret:
     {
-      Code = bitc::FUNC_CODE_INST_RET;
+      Code = naclbitc::FUNC_CODE_INST_RET;
       unsigned NumOperands = I.getNumOperands();
       if (NumOperands == 0)
         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
@@ -1213,7 +1213,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   case Instruction::Br:
     {
-      Code = bitc::FUNC_CODE_INST_BR;
+      Code = naclbitc::FUNC_CODE_INST_BR;
       const BranchInst &II = cast<BranchInst>(I);
       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
       if (II.isConditional()) {
@@ -1228,7 +1228,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
       // explicitly to store large APInt numbers.
       SmallVector<uint64_t, 128> Vals64;
 
-      Code = bitc::FUNC_CODE_INST_SWITCH;
+      Code = naclbitc::FUNC_CODE_INST_SWITCH;
       const SwitchInst &SI = cast<SwitchInst>(I);
 
       uint32_t SwitchRecordHeader = SI.hash() | (SWITCH_INST_MAGIC << 16);
@@ -1284,7 +1284,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     }
     break;
   case Instruction::IndirectBr:
-    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
+    Code = naclbitc::FUNC_CODE_INST_INDIRECTBR;
     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
     // Encode the address operand as relative, but not the basic blocks.
     pushValue(I.getOperand(0), InstID, Vals, VE);
@@ -1297,7 +1297,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     const Value *Callee(II->getCalledValue());
     PointerType *PTy = cast<PointerType>(Callee->getType());
     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
-    Code = bitc::FUNC_CODE_INST_INVOKE;
+    Code = naclbitc::FUNC_CODE_INST_INVOKE;
 
     Vals.push_back(VE.getAttributeID(II->getAttributes()));
     Vals.push_back(II->getCallingConv());
@@ -1318,17 +1318,17 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   }
   case Instruction::Resume:
-    Code = bitc::FUNC_CODE_INST_RESUME;
+    Code = naclbitc::FUNC_CODE_INST_RESUME;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     break;
   case Instruction::Unreachable:
-    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
+    Code = naclbitc::FUNC_CODE_INST_UNREACHABLE;
     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
     break;
 
   case Instruction::PHI: {
     const PHINode &PN = cast<PHINode>(I);
-    Code = bitc::FUNC_CODE_INST_PHI;
+    Code = naclbitc::FUNC_CODE_INST_PHI;
     // With the newer instruction encoding, forward references could give
     // negative valued IDs.  This is most common for PHIs, so we use
     // signed VBRs.
@@ -1346,7 +1346,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
 
   case Instruction::LandingPad: {
     const LandingPadInst &LP = cast<LandingPadInst>(I);
-    Code = bitc::FUNC_CODE_INST_LANDINGPAD;
+    Code = naclbitc::FUNC_CODE_INST_LANDINGPAD;
     Vals.push_back(VE.getTypeID(LP.getType()));
     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
     Vals.push_back(LP.isCleanup());
@@ -1362,7 +1362,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
   }
 
   case Instruction::Alloca:
-    Code = bitc::FUNC_CODE_INST_ALLOCA;
+    Code = naclbitc::FUNC_CODE_INST_ALLOCA;
     Vals.push_back(VE.getTypeID(I.getType()));
     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
@@ -1371,10 +1371,10 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
 
   case Instruction::Load:
     if (cast<LoadInst>(I).isAtomic()) {
-      Code = bitc::FUNC_CODE_INST_LOADATOMIC;
+      Code = naclbitc::FUNC_CODE_INST_LOADATOMIC;
       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     } else {
-      Code = bitc::FUNC_CODE_INST_LOAD;
+      Code = naclbitc::FUNC_CODE_INST_LOAD;
       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
     }
@@ -1387,9 +1387,9 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   case Instruction::Store:
     if (cast<StoreInst>(I).isAtomic())
-      Code = bitc::FUNC_CODE_INST_STOREATOMIC;
+      Code = naclbitc::FUNC_CODE_INST_STOREATOMIC;
     else
-      Code = bitc::FUNC_CODE_INST_STORE;
+      Code = naclbitc::FUNC_CODE_INST_STORE;
     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
@@ -1400,7 +1400,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     }
     break;
   case Instruction::AtomicCmpXchg:
-    Code = bitc::FUNC_CODE_INST_CMPXCHG;
+    Code = naclbitc::FUNC_CODE_INST_CMPXCHG;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
@@ -1411,7 +1411,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
     break;
   case Instruction::AtomicRMW:
-    Code = bitc::FUNC_CODE_INST_ATOMICRMW;
+    Code = naclbitc::FUNC_CODE_INST_ATOMICRMW;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
     Vals.push_back(GetEncodedRMWOperation(
@@ -1422,7 +1422,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
                      cast<AtomicRMWInst>(I).getSynchScope()));
     break;
   case Instruction::Fence:
-    Code = bitc::FUNC_CODE_INST_FENCE;
+    Code = naclbitc::FUNC_CODE_INST_FENCE;
     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
     break;
@@ -1431,7 +1431,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 
-    Code = bitc::FUNC_CODE_INST_CALL;
+    Code = naclbitc::FUNC_CODE_INST_CALL;
 
     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
@@ -1455,7 +1455,7 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     break;
   }
   case Instruction::VAArg:
-    Code = bitc::FUNC_CODE_INST_VAARG;
+    Code = naclbitc::FUNC_CODE_INST_VAARG;
     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
     Vals.push_back(VE.getTypeID(I.getType())); // restype.
@@ -1471,7 +1471,7 @@ static void WriteValueSymbolTable(const ValueSymbolTable &VST,
                                   const NaClValueEnumerator &VE,
                                   NaClBitstreamWriter &Stream) {
   if (VST.empty()) return;
-  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
+  Stream.EnterSubblock(naclbitc::VALUE_SYMTAB_BLOCK_ID, 4);
 
   // FIXME: Set up the abbrev, we know how many values there are!
   // FIXME: We know if the type names can use 7-bit ascii.
@@ -1501,11 +1501,11 @@ static void WriteValueSymbolTable(const ValueSymbolTable &VST,
     // VST_BBENTRY: [bbid, namechar x N]
     unsigned Code;
     if (isa<BasicBlock>(SI->getValue())) {
-      Code = bitc::VST_CODE_BBENTRY;
+      Code = naclbitc::VST_CODE_BBENTRY;
       if (isChar6)
         AbbrevToUse = VST_BBENTRY_6_ABBREV;
     } else {
-      Code = bitc::VST_CODE_ENTRY;
+      Code = naclbitc::VST_CODE_ENTRY;
       if (isChar6)
         AbbrevToUse = VST_ENTRY_6_ABBREV;
       else if (is7Bit)
@@ -1527,7 +1527,7 @@ static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 /// WriteFunction - Emit a function body to the module stream.
 static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
                           NaClBitstreamWriter &Stream) {
-  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
+  Stream.EnterSubblock(naclbitc::FUNCTION_BLOCK_ID, 4);
   VE.incorporateFunction(F);
 
   SmallVector<unsigned, 64> Vals;
@@ -1535,7 +1535,7 @@ static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
   // Emit the number of basic blocks, so the reader can create them ahead of
   // time.
   Vals.push_back(VE.getBasicBlocks().size());
-  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
+  Stream.EmitRecord(naclbitc::FUNC_CODE_DECLAREBLOCKS, Vals);
   Vals.clear();
 
   // If there are function-local constants, emit them now.
@@ -1571,7 +1571,7 @@ static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
         // nothing todo.
       } else if (DL == LastDL) {
         // Just repeat the same debug loc as last time.
-        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
+        Stream.EmitRecord(naclbitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
       } else {
         MDNode *Scope, *IA;
         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
@@ -1580,7 +1580,7 @@ static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
         Vals.push_back(DL.getCol());
         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
-        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
+        Stream.EmitRecord(naclbitc::FUNC_CODE_DEBUG_LOC, Vals);
         Vals.clear();
 
         LastDL = DL;
@@ -1609,38 +1609,38 @@ static void WriteBlockInfo(const NaClValueEnumerator &VE, NaClBitstreamWriter &S
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
-    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_ENTRY_8_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
 
   { // 7-bit fixed width VST_ENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::VST_CODE_ENTRY));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
-    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_ENTRY_7_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // 6-bit char6 VST_ENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::VST_CODE_ENTRY));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
-    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_ENTRY_6_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // 6-bit char6 VST_BBENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::VST_CODE_BBENTRY));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
-    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_BBENTRY_6_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
@@ -1649,39 +1649,39 @@ static void WriteBlockInfo(const NaClValueEnumerator &VE, NaClBitstreamWriter &S
 
   { // SETTYPE abbrev for CONSTANTS_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_SETTYPE));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
                               Log2_32_Ceil(VE.getTypes().size()+1)));
-    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
 
   { // INTEGER abbrev for CONSTANTS_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_INTEGER));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
-    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
 
   { // CE_CAST abbrev for CONSTANTS_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_CE_CAST));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
                               Log2_32_Ceil(VE.getTypes().size()+1)));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
 
-    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // NULL abbrev for CONSTANTS_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
-    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::CST_CODE_NULL));
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_NULL_Abbrev)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
@@ -1690,66 +1690,66 @@ static void WriteBlockInfo(const NaClValueEnumerator &VE, NaClBitstreamWriter &S
 
   { // INST_LOAD abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_LOAD));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // INST_BINOP abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_BINOP));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_BINOP));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // INST_CAST abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_CAST));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
                               Log2_32_Ceil(VE.getTypes().size()+1)));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
 
   { // INST_RET abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_RET));
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // INST_RET abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_RET));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
+    Abbv->Add(BitCodeAbbrevOp(naclbitc::FUNC_CODE_INST_UNREACHABLE));
+    if (Stream.EmitBlockInfoAbbrev(naclbitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
@@ -1759,12 +1759,12 @@ static void WriteBlockInfo(const NaClValueEnumerator &VE, NaClBitstreamWriter &S
 
 /// WriteModule - Emit the specified module to the bitstream.
 static void WriteModule(const Module *M, NaClBitstreamWriter &Stream) {
-  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
+  Stream.EnterSubblock(naclbitc::MODULE_BLOCK_ID, 3);
 
   SmallVector<unsigned, 1> Vals;
   unsigned CurVersion = 1;
   Vals.push_back(CurVersion);
-  Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
+  Stream.EmitRecord(naclbitc::MODULE_CODE_VERSION, Vals);
 
   // Analyze the module, enumerating globals, functions, etc.
   NaClValueEnumerator VE(M);
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index dd30c77a5d..7e32507e91 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -44,6 +44,7 @@ add_subdirectory(llvm-mcmarkup)
 add_subdirectory(llvm-symbolizer)
 add_subdirectory(pnacl-abicheck)
 add_subdirectory(pnacl-freeze)
+add_subdirectory(pnacl-thaw)
 add_subdirectory(bc-wrap)
 
 if( NOT WIN32 )
diff --git a/tools/Makefile b/tools/Makefile
index 5a51ba8948..f46e3b5fac 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -35,7 +35,7 @@ PARALLEL_DIRS := opt llvm-as llvm-dis \
                  llvm-diff macho-dump llvm-objdump llvm-readobj \
 	         llvm-rtdyld llvm-dwarfdump llvm-cov \
 	         llvm-size llvm-stress llvm-mcmarkup bc-wrap pso-stub \
-	         llvm-symbolizer pnacl-abicheck pnacl-freeze
+	         llvm-symbolizer pnacl-abicheck pnacl-freeze pnacl-thaw
 
 # If Intel JIT Events support is configured, build an extra tool to test it.
 ifeq ($(USE_INTEL_JITEVENTS), 1)
diff --git a/tools/pnacl-thaw/CMakeLists.txt b/tools/pnacl-thaw/CMakeLists.txt
new file mode 100644
index 0000000000..91b818efe6
--- /dev/null
+++ b/tools/pnacl-thaw/CMakeLists.txt
@@ -0,0 +1,5 @@
+set(LLVM_LINK_COMPONENTS bitwriter naclbitreader)
+
+add_llvm_tool(pnacl-thaw
+  pnacl-thaw.cpp
+  )
diff --git a/tools/pnacl-thaw/LLVMBuild.txt b/tools/pnacl-thaw/LLVMBuild.txt
new file mode 100644
index 0000000000..864da2cbd5
--- /dev/null
+++ b/tools/pnacl-thaw/LLVMBuild.txt
@@ -0,0 +1,16 @@
+;===- ./tools/pnacl-thaw/LLVMBuild.txt -----------------------*- Conf -*--===;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Tool
+name = pnacl-thaw
+parent = Tools
+required_libraries = BitWriter NaClBitReader
diff --git a/tools/pnacl-thaw/Makefile b/tools/pnacl-thaw/Makefile
new file mode 100644
index 0000000000..8e7699e185
--- /dev/null
+++ b/tools/pnacl-thaw/Makefile
@@ -0,0 +1,17 @@
+##===- tools/pnacl-thaw/Makefile ---------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL := ../..
+TOOLNAME := pnacl-thaw
+LINK_COMPONENTS := bitwriter naclbitreader
+
+# This tool has no plugins, optimize startup time.
+TOOL_NO_EXPORTS := 1
+
+include $(LEVEL)/Makefile.common
diff --git a/tools/pnacl-thaw/pnacl-thaw.cpp b/tools/pnacl-thaw/pnacl-thaw.cpp
new file mode 100644
index 0000000000..b28c357165
--- /dev/null
+++ b/tools/pnacl-thaw/pnacl-thaw.cpp
@@ -0,0 +1,94 @@
+/* Copyright 2013 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can
+ * be found in the LICENSE file.
+ */
+
+//===-- pnacl-thaw.cpp - The low-level NaCl bitcode thawer ----------------===//
+//
+//===----------------------------------------------------------------------===//
+//
+// Converts NaCl wire format back to LLVM bitcode.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/LLVMContext.h"
+// Note: We need the following to provide the API for calling the NaCl
+// Bitcode Reader to read the frozen file.
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+// Note: We need the following to provide the API for calling the (LLVM)
+// Bitcode Writer to generate the corresponding LLVM bitcode file.
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+using namespace llvm;
+
+static cl::opt<std::string>
+OutputFilename("o", cl::desc("Specify thawed pexe filename"),
+	       cl::value_desc("filename"));
+
+static cl::opt<std::string>
+InputFilename(cl::Positional, cl::desc("<frozen file>"), cl::Required);
+
+static void WriteOutputFile(const Module *M) {
+
+  std::string ThawedFilename =
+    (OutputFilename.size() == 0 ? (InputFilename + ".thawed") : OutputFilename);
+
+  std::string ErrorInfo;
+  OwningPtr<tool_output_file> Out
+    (new tool_output_file(ThawedFilename.c_str(), ErrorInfo,
+			  raw_fd_ostream::F_Binary));
+  if (!ErrorInfo.empty()) {
+    errs() << ErrorInfo << '\n';
+    exit(1);
+  }
+
+  WriteBitcodeToFile(M, Out->os());
+
+  // Declare success.
+  Out->keep();
+}
+
+int main(int argc, char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+
+  LLVMContext &Context = getGlobalContext();
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+  cl::ParseCommandLineOptions(
+      argc, argv, "Converts NaCl pexe wire format into LLVM bitcode format\n");
+
+  std::string ErrorMessage;
+  std::auto_ptr<Module> M;
+
+  // Use the bitcode streaming interface
+  DataStreamer *streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
+  if (streamer) {
+    std::string DisplayFilename = InputFilename;
+    M.reset(getNaClStreamedBitcodeModule(DisplayFilename, streamer, Context,
+                                         &ErrorMessage));
+    if(M.get() != 0 && M->MaterializeAllPermanently(&ErrorMessage)) {
+      M.reset();
+    }
+  }
+
+  if (M.get() == 0) {
+    errs() << argv[0] << ": ";
+    if (ErrorMessage.size())
+      errs() << ErrorMessage << "\n";
+    else
+      errs() << "bitcode didn't read correctly.\n";
+    return 1;
+  }
+
+  WriteOutputFile(M.get());
+  return 0;
+}