Rebased PNaCl localmods in LLVM to 223109

lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp

+//===- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "NaClBitcodeReader"
+
+#include "NaClBitcodeReader.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/NaCl/PNaClABITypeChecker.h"
+#include "llvm/Bitcode/NaCl/NaClBitcodeDecoders.h"
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+#include "llvm/IR/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/Debug.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+
+cl::opt<bool>
+llvm::PNaClAllowLocalSymbolTables(
+    "allow-local-symbol-tables",
+    cl::desc("Allow (function) local symbol tables in PNaCl bitcode files"),
+    cl::init(false));
+
+void NaClBitcodeReader::FreeState() {
+  std::vector<Type*>().swap(TypeList);
+  ValueList.clear();
+
+  std::vector<Function*>().swap(FunctionsWithBodies);
+  DeferredFunctionInfo.clear();
+}
+
+//===----------------------------------------------------------------------===//
+//  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;
+}
+
+void NaClBitcodeReaderValueList::AssignValue(Value *V, unsigned Idx) {
+  assert(V);
+  if (Idx == size()) {
+    push_back(V);
+    return;
+  }
+
+  if (Idx >= size())
+    resize(Idx+1);
+
+  WeakVH &OldV = ValuePtrs[Idx];
+  if (OldV == 0) {
+    OldV = V;
+    return;
+  }
+
+  // If there was a forward reference to this value, replace it.
+  Value *PrevVal = OldV;
+  OldV->replaceAllUsesWith(V);
+  delete PrevVal;
+}
+
+void NaClBitcodeReaderValueList::OverwriteValue(Value *V, unsigned Idx) {
+  ValuePtrs[Idx] = V;
+}
+
+Value *NaClBitcodeReaderValueList::getValueFwdRef(unsigned Idx) {
+  if (Idx >= size())
+    return 0;
+
+  if (Value *V = ValuePtrs[Idx])
+    return V;
+
+  return 0;
+}
+
+bool NaClBitcodeReaderValueList::createValueFwdRef(unsigned Idx, Type *Ty) {
+  if (Idx >= size())
+    resize(Idx + 1);
+
+  // Return an error if this a duplicate definition of Idx.
+  if (ValuePtrs[Idx])
+    return true;
+
+  // No type specified, must be invalid reference.
+  if (Ty == 0)
+    return true;
+
+  // Create a placeholder, which will later be RAUW'd.
+  ValuePtrs[Idx] = new Argument(Ty);
+  return false;
+}
+
+namespace {
+class NaClBitcodeErrorCategoryType : public std::error_category {
+  const char *name() const LLVM_NOEXCEPT override {
+    return "pnacl.bitcode";
+  }
+  std::string message(int IndexError) const override {
+    switch(static_cast<NaClBitcodeReader::ErrorType>(IndexError)) {
+    case NaClBitcodeReader::CouldNotFindFunctionInStream:
+      return "Unable to find function in bitcode stream.";
+    case NaClBitcodeReader::InsufficientFunctionProtos:
+      return "Insufficient function protos";
+    case NaClBitcodeReader::InvalidBitstream:
+      return "Error in bitstream format";
+    case NaClBitcodeReader::InvalidBlock:
+      return "Invalid block found in bitcode file";
+    case NaClBitcodeReader::InvalidConstantReference:
+      return "Bad constant reference";
+    case NaClBitcodeReader::InvalidDataAfterModule:
+      return "Invalid data after module";
+    case NaClBitcodeReader::InvalidInstructionWithNoBB:
+      return "No basic block for instruction";
+    case NaClBitcodeReader::InvalidMultipleBlocks:
+      return "Multiple blocks for a kind of block that should have only one";
+    case NaClBitcodeReader::InvalidRecord:
+      return "Record doesn't have expected size or structure";
+    case NaClBitcodeReader::InvalidSkippedBlock:
+      return "Unable to skip unknown block in bitcode file";
+    case NaClBitcodeReader::InvalidType:
+      return "Invalid type in record";
+    case NaClBitcodeReader::InvalidTypeForValue:
+      return "Type of value in record incorrect";
+    case NaClBitcodeReader::InvalidValue:
+      return "Invalid value in record";
+    case NaClBitcodeReader::MalformedBlock:
+      return "Malformed block. Unable to advance over block";
+    }
+    llvm_unreachable("Unknown error type!");
+  }
+};
+} // end of anonomous namespace.
+
+const std::error_category &NaClBitcodeReader::BitcodeErrorCategory() {
+  static NaClBitcodeErrorCategoryType ErrCat;
+  return ErrCat;
+}
+
+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
+//===----------------------------------------------------------------------===//
+
+
+namespace {
+
+static const unsigned MaxAlignmentExponent = 29;
+static_assert(
+    (1u << MaxAlignmentExponent) == Value::MaximumAlignment,
+    "Inconsistency between Value.MaxAlignment and PNaCl alignment limit");
+}
+
+std::error_code NaClBitcodeReader::Error(ErrorType E,
+                                         const std::string &Message) const {
+  if (Verbose) {
+    uint64_t Bit = Stream.GetCurrentBitNo();
+    *Verbose << "Error: (" <<  (Bit / CHAR_BIT) << ":"
+             << static_cast<unsigned>(Bit % CHAR_BIT)
+             << ") " << Message << "\n";
+  }
+  return Error(E);
+}
+
+std::error_code NaClBitcodeReader::getAlignmentValue(
+    uint64_t Exponent, unsigned &Alignment) {
+  if (Exponent > MaxAlignmentExponent + 1) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << "Alignment can't be greater than 2**" << MaxAlignmentExponent
+           << ". Found: 2**" << (Exponent - 1);
+    return Error(InvalidValue, StrBuf.str());
+  }
+  Alignment = (1 << static_cast<unsigned>(Exponent)) >> 1;
+  return std::error_code();
+}
+
+std::error_code NaClBitcodeReader::ParseTypeTable() {
+  DEBUG(dbgs() << "-> ParseTypeTable\n");
+  if (Stream.EnterSubBlock(naclbitc::TYPE_BLOCK_ID_NEW))
+    return Error(InvalidRecord, "Malformed block record");
+
+  std::error_code result = ParseTypeTableBody();
+  if (!result)
+    DEBUG(dbgs() << "<- ParseTypeTable\n");
+  return result;
+}
+
+std::error_code NaClBitcodeReader::ParseTypeTableBody() {
+  if (!TypeList.empty())
+    return Error(InvalidMultipleBlocks, "Multiple TYPE_BLOCKs found!");
+
+  SmallVector<uint64_t, 64> Record;
+  unsigned NumRecords = 0;
+
+  // Read all the records for this type table.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance(0, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock:
+      return Error(InvalidBlock, "Invalid block found in the types block");
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "Malformed types block");
+    case NaClBitstreamEntry::EndBlock:
+      if (NumRecords != TypeList.size())
+        return Error(MalformedBlock,
+                     "Invalid forward reference in the types block");
+      return std::error_code();
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    Record.clear();
+    Type *ResultTy = 0;
+    unsigned TypeCode = Stream.readRecord(Entry.ID, Record);
+    switch (TypeCode) {
+    default: {
+      std::string Message;
+      raw_string_ostream StrM(Message);
+      StrM << "Unknown type code in type table: " << TypeCode;
+      StrM.flush();
+      return Error(InvalidValue, Message);
+    }
+
+    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(InvalidRecord, "Invalid TYPE_CODE_NUMENTRY record");
+      TypeList.resize(Record[0]);
+      // No type was defined, skip the checks that follow the switch.
+      continue;
+
+    case naclbitc::TYPE_CODE_VOID: // VOID
+      if (Record.size() != 0)
+        return Error(InvalidRecord, "Invalid TYPE_CODE_VOID record");
+      ResultTy = Type::getVoidTy(Context);
+      break;
+
+    case naclbitc::TYPE_CODE_FLOAT: // FLOAT
+      if (Record.size() != 0)
+        return Error(InvalidRecord, "Invalid TYPE_CODE_FLOAT record");
+      ResultTy = Type::getFloatTy(Context);
+      break;
+
+    case naclbitc::TYPE_CODE_DOUBLE: // DOUBLE
+      if (Record.size() != 0)
+        return Error(InvalidRecord, "Invalid TYPE_CODE_DOUBLE record");
+      ResultTy = Type::getDoubleTy(Context);
+      break;
+
+    case naclbitc::TYPE_CODE_INTEGER: // INTEGER: [width]
+      if (Record.size() != 1)
+        return Error(InvalidRecord, "Invalid TYPE_CODE_INTEGER record");
+      ResultTy = IntegerType::get(Context, Record[0]);
+      break;
+
+    case naclbitc::TYPE_CODE_FUNCTION: {
+      // FUNCTION: [vararg, retty, paramty x N]
+      if (Record.size() < 2)
+        return Error(InvalidRecord, "Invalid TYPE_CODE_FUNCTION 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(InvalidType, "invalid type in function type");
+
+      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
+      break;
+    }
+    case naclbitc::TYPE_CODE_VECTOR: { // VECTOR: [numelts, eltty]
+      if (Record.size() != 2)
+        return Error(InvalidRecord, "Invalid VECTOR type record");
+      if ((ResultTy = getTypeByID(Record[1])))
+        ResultTy = VectorType::get(ResultTy, Record[0]);
+      else
+        return Error(InvalidType, "invalid type in vector type");
+      break;
+    }
+    }
+
+    if (NumRecords >= TypeList.size())
+      return Error(MalformedBlock, "invalid TYPE table");
+    assert(ResultTy && "Didn't read a type?");
+    assert(TypeList[NumRecords] == 0 && "Already read type?");
+    TypeList[NumRecords++] = ResultTy;
+  }
+  return std::error_code();
+}
+
+namespace {
+
+// Class to process globals in two passes. In the first pass, build
+// the corresponding global variables with no initializers. In the
+// second pass, add initializers. The purpose of putting off
+// initializers is to make sure that we don't need to generate
+// placeholders for relocation records, and the corresponding cost
+// of duplicating initializers when these placeholders are replaced.
+class ParseGlobalsHandler {
+  ParseGlobalsHandler(const ParseGlobalsHandler &H) LLVM_DELETED_FUNCTION;
+  void operator=(const ParseGlobalsHandler &H) LLVM_DELETED_FUNCTION;
+
+  NaClBitcodeReader &Reader;
+  NaClBitcodeReaderValueList &ValueList;
+  NaClBitstreamCursor &Stream;
+  LLVMContext &Context;
+  Module *TheModule;
+
+  // Holds read data record.
+  SmallVector<uint64_t, 64> Record;
+  // True when processing a global variable. Stays true until all records
+  // are processed, and the global variable is created.
+  bool ProcessingGlobal;
+  // The number of initializers needed for the global variable.
+  unsigned VarInitializersNeeded ;
+  unsigned FirstValueNo;
+  // The index of the next global variable.
+  unsigned NextValueNo;
+  // The number of expected global variable definitions.
+  unsigned NumGlobals;
+  // The bit to go back to to generate initializers.
+  uint64_t StartBit;
+
+  void InitPass() {
+    Stream.JumpToBit(StartBit);
+    ProcessingGlobal = false;
+    VarInitializersNeeded = 0;
+    NextValueNo = FirstValueNo;
+  }
+
+public:
+  ParseGlobalsHandler(NaClBitcodeReader &Reader,
+                      NaClBitcodeReaderValueList &ValueList,
+                      NaClBitstreamCursor &Stream,
+                      LLVMContext &Context,
+                      Module *TheModule)
+      : Reader(Reader),
+        ValueList(ValueList),
+        Stream(Stream),
+        Context(Context),
+        TheModule(TheModule),
+        FirstValueNo(ValueList.size()),
+        NumGlobals(0),
+        StartBit(Stream.GetCurrentBitNo()) {}
+
+  std::error_code GenerateGlobalVarsPass() {
+    InitPass();
+
+    // The type for the initializer of the global variable.
+    SmallVector<Type*, 10> VarType;
+    // The alignment value defined for the global variable.
+    unsigned VarAlignment = 0;
+    // True if the variable is read-only.
+    bool VarIsConstant = false;
+
+    // Read all records to build global variables without initializers.
+    while (1) {
+      NaClBitstreamEntry Entry =
+        Stream.advance(NaClBitstreamCursor::AF_DontPopBlockAtEnd, nullptr);
+      switch (Entry.Kind) {
+      case NaClBitstreamEntry::SubBlock:
+        return Reader.Error(NaClBitcodeReader::InvalidBlock,
+                            "Invalid block in the global vars block");
+      case NaClBitstreamEntry::Error:
+        return Reader.Error(NaClBitcodeReader::MalformedBlock,
+                            "Error in the global vars block");
+      case NaClBitstreamEntry::EndBlock:
+        if (ProcessingGlobal || NumGlobals != (NextValueNo - FirstValueNo))
+          return Reader.Error(NaClBitcodeReader::MalformedBlock,
+                              "Error in the global vars block");
+        return std::error_code();
+      case NaClBitstreamEntry::Record:
+        // The interesting case.
+        break;
+      }
+
+      // Read a record.
+      Record.clear();
+      unsigned Bitcode = Stream.readRecord(Entry.ID, Record);
+      switch (Bitcode) {
+      default:
+        return Reader.Error(NaClBitcodeReader::InvalidValue,
+                            "Unknown global variable entry");
+      case naclbitc::GLOBALVAR_VAR:
+        // Start the definition of a global variable.
+        if (ProcessingGlobal || Record.size() != 2)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_VAR record");
+        ProcessingGlobal = true;
+        if (std::error_code EC =
+            Reader.getAlignmentValue(Record[0], VarAlignment))
+          return EC;
+        VarIsConstant = Record[1] != 0;
+        // Assume (by default) there is a single initializer.
+        VarInitializersNeeded = 1;
+        break;
+      case naclbitc::GLOBALVAR_COMPOUND:
+        // Global variable has multiple initializers. Changes the
+        // default number of initializers to the given value in
+        // Record[0].
+        if (!ProcessingGlobal || !VarType.empty() ||
+            VarInitializersNeeded != 1 || Record.size() != 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_COMPOUND record");
+        VarInitializersNeeded = Record[0];
+        break;
+      case naclbitc::GLOBALVAR_ZEROFILL: {
+        // Define a type that defines a sequence of zero-filled bytes.
+        if (!ProcessingGlobal || Record.size() != 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_ZEROFILL record");
+        VarType.push_back(ArrayType::get(
+            Type::getInt8Ty(Context), Record[0]));
+        break;
+      }
+      case naclbitc::GLOBALVAR_DATA: {
+        // Defines a type defined by a sequence of byte values.
+        if (!ProcessingGlobal || Record.size() < 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_DATA record");
+        VarType.push_back(ArrayType::get(
+            Type::getInt8Ty(Context), Record.size()));
+        break;
+      }
+      case naclbitc::GLOBALVAR_RELOC: {
+        // Define a relocation initializer type.
+        if (!ProcessingGlobal || Record.size() < 1 || Record.size() > 2)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_RELOC record");
+        VarType.push_back(IntegerType::get(Context, 32));
+        break;
+      }
+      case naclbitc::GLOBALVAR_COUNT:
+        if (Record.size() != 1 || NumGlobals != 0)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Invalid global count record");
+        NumGlobals = Record[0];
+        break;
+      }
+
+      // If more initializers needed for global variable, continue processing.
+      if (!ProcessingGlobal || VarType.size() < VarInitializersNeeded)
+        continue;
+
+      Type *Ty = 0;
+      switch (VarType.size()) {
+      case 0:
+        return Reader.Error(
+            NaClBitcodeReader::InvalidRecord,
+            "No initializer for global variable in global vars block");
+      case 1:
+        Ty = VarType[0];
+        break;
+      default:
+        Ty = StructType::get(Context, VarType, true);
+        break;
+      }
+      GlobalVariable *GV = new GlobalVariable(
+          *TheModule, Ty, VarIsConstant,
+          GlobalValue::InternalLinkage, NULL, "");
+      GV->setAlignment(VarAlignment);
+      ValueList.AssignValue(GV, NextValueNo);
+      ++NextValueNo;
+      ProcessingGlobal = false;
+      VarAlignment = 0;
+      VarIsConstant = false;
+      VarInitializersNeeded = 0;
+      VarType.clear();
+    }
+    return std::error_code();
+  }
+
+  std::error_code GenerateGlobalVarInitsPass() {
+    InitPass();
+    // The initializer for the global variable.
+    SmallVector<Constant *, 10> VarInit;
+
+    while (1) {
+      NaClBitstreamEntry Entry =
+        Stream.advance(NaClBitstreamCursor::AF_DontAutoprocessAbbrevs, nullptr);
+      switch (Entry.Kind) {
+      case NaClBitstreamEntry::SubBlock:
+        return Reader.Error(NaClBitcodeReader::InvalidBlock,
+                            "Invalid block in the global vars block");
+      case NaClBitstreamEntry::Error:
+        return Reader.Error(NaClBitcodeReader::MalformedBlock,
+                            "Error in the global vars block");
+      case NaClBitstreamEntry::EndBlock:
+        if (ProcessingGlobal || NumGlobals != (NextValueNo - FirstValueNo))
+          return Reader.Error(NaClBitcodeReader::MalformedBlock,
+                              "Error in the global vars block");
+        return std::error_code();
+      case NaClBitstreamEntry::Record:
+        if (Entry.ID == naclbitc::DEFINE_ABBREV) {
+          Stream.SkipAbbrevRecord();
+          continue;
+        }
+        // The interesting case.
+        break;
+      }
+
+      // Read a record.
+      Record.clear();
+      unsigned Bitcode = Stream.readRecord(Entry.ID, Record);
+      switch (Bitcode) {
+      default:
+        return Reader.Error(NaClBitcodeReader::InvalidValue,
+                            "Unknown global variable entry 2");
+      case naclbitc::GLOBALVAR_VAR:
+        // Start the definition of a global variable.
+        ProcessingGlobal = true;
+        // Assume (by default) there is a single initializer.
+        VarInitializersNeeded = 1;
+        break;
+      case naclbitc::GLOBALVAR_COMPOUND:
+        // Global variable has multiple initializers. Changes the
+        // default number of initializers to the given value in
+        // Record[0].
+        if (!ProcessingGlobal || !VarInit.empty() ||
+            VarInitializersNeeded != 1 || Record.size() != 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_COMPOUND record");
+        VarInitializersNeeded = Record[0];
+        break;
+      case naclbitc::GLOBALVAR_ZEROFILL: {
+        // Define an initializer that defines a sequence of zero-filled bytes.
+        if (!ProcessingGlobal || Record.size() != 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_ZEROFILL record");
+        Type *Ty = ArrayType::get(Type::getInt8Ty(Context),
+                                  Record[0]);
+        Constant *Zero = ConstantAggregateZero::get(Ty);
+        VarInit.push_back(Zero);
+        break;
+      }
+      case naclbitc::GLOBALVAR_DATA: {
+        // Defines an initializer defined by a sequence of byte values.
+        if (!ProcessingGlobal || Record.size() < 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_DATA record");
+        unsigned Size = Record.size();
+        uint8_t *Buf = new uint8_t[Size];
+        assert(Buf);
+        for (unsigned i = 0; i < Size; ++i)
+          Buf[i] = Record[i];
+        Constant *Init = ConstantDataArray::get(
+            Context, ArrayRef<uint8_t>(Buf, Buf + Size));
+        VarInit.push_back(Init);
+        delete[] Buf;
+        break;
+      }
+      case naclbitc::GLOBALVAR_RELOC: {
+        // Define a relocation initializer.
+        if (!ProcessingGlobal || Record.size() < 1 || Record.size() > 2)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Bad GLOBALVAR_RELOC record");
+        Constant *BaseVal = cast<Constant>(ValueList[Record[0]]);
+        Type *IntPtrType = IntegerType::get(Context, 32);
+        Constant *Val = ConstantExpr::getPtrToInt(BaseVal, IntPtrType);
+        if (Record.size() == 2) {
+          uint32_t Addend = Record[1];
+          Val = ConstantExpr::getAdd(Val, ConstantInt::get(IntPtrType,
+                                                           Addend));
+        }
+        VarInit.push_back(Val);
+        break;
+      }
+      case naclbitc::GLOBALVAR_COUNT:
+        if (Record.size() != 1)
+          return Reader.Error(NaClBitcodeReader::InvalidRecord,
+                              "Invalid global count record");
+        // Note: NumGlobals should have been set in GenerateGlobalVarsPass.
+        // Fail if methods are called in wrong order.
+        assert(NumGlobals == Record[0]);
+        break;
+      }
+
+      // If more initializers needed for global variable, continue processing.
+      if (!ProcessingGlobal || VarInit.size() < VarInitializersNeeded)
+        continue;
+
+      Constant *Init = 0;
+      switch (VarInit.size()) {
+      case 0:
+        return Reader.Error(NaClBitcodeReader::InvalidRecord,
+            "No initializer for global variable in global vars block");
+      case 1:
+        Init = VarInit[0];
+        break;
+      default:
+        Init = ConstantStruct::getAnon(Context, VarInit, true);
+        break;
+      }
+      cast<GlobalVariable>(ValueList[NextValueNo])->setInitializer(Init);
+      ++NextValueNo;
+      ProcessingGlobal = false;
+      VarInitializersNeeded = 0;
+      VarInit.clear();
+    }
+    return std::error_code();
+  }
+};
+
+} // End anonymous namespace.
+
+std::error_code NaClBitcodeReader::ParseGlobalVars() {
+  if (Stream.EnterSubBlock(naclbitc::GLOBALVAR_BLOCK_ID))
+    return Error(InvalidRecord, "Malformed block record");
+
+  ParseGlobalsHandler PassHandler(*this, ValueList, Stream, Context, TheModule);
+  if (std::error_code EC = PassHandler.GenerateGlobalVarsPass())
+    return EC;
+  return PassHandler.GenerateGlobalVarInitsPass();
+}
+
+std::error_code NaClBitcodeReader::ParseValueSymbolTable() {
+  DEBUG(dbgs() << "-> ParseValueSymbolTable\n");
+  if (Stream.EnterSubBlock(naclbitc::VALUE_SYMTAB_BLOCK_ID))
+    return Error(InvalidRecord, "Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records for this value table.
+  SmallString<128> ValueName;
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance(0, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock:
+      return Error(InvalidBlock,
+                   "Invalid block in the value symbol table block");
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "malformed value symbol table block");
+    case NaClBitstreamEntry::EndBlock:
+      DEBUG(dbgs() << "<- ParseValueSymbolTable\n");
+      return std::error_code();
+    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(InvalidRecord, "Invalid VST_ENTRY record");
+      unsigned ValueID = Record[0];
+      if (ValueID >= ValueList.size())
+        return Error(InvalidValue, "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(InvalidRecord, "Invalid VST_BBENTRY record");
+      BasicBlock *BB = getBasicBlock(Record[0]);
+      if (BB == 0)
+        return Error(InvalidValue, "Invalid BB ID in VST_BBENTRY record");
+
+      BB->setName(StringRef(ValueName.data(), ValueName.size()));
+      ValueName.clear();
+      break;
+    }
+    }
+  }
+}
+
+std::error_code NaClBitcodeReader::ParseConstants() {
+  DEBUG(dbgs() << "-> ParseConstants\n");
+  if (Stream.EnterSubBlock(naclbitc::CONSTANTS_BLOCK_ID))
+    return Error(InvalidRecord, "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.advance(0, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::SubBlock:
+      return Error(InvalidBlock, "Invalid block in function constants block");
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "malformed function constants block");
+    case NaClBitstreamEntry::EndBlock:
+      if (NextCstNo != ValueList.size())
+        return Error(InvalidConstantReference,
+                     "Invalid constant reference!");
+      DEBUG(dbgs() << "<- ParseConstants\n");
+      return std::error_code();
+    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: {
+      std::string Message;
+      raw_string_ostream StrM(Message);
+      StrM << "Invalid Constant code: " << BitCode;
+      StrM.flush();
+      return Error(InvalidValue, Message);
+    }
+    case naclbitc::CST_CODE_UNDEF:     // UNDEF
+      V = UndefValue::get(CurTy);
+      break;
+    case naclbitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
+      if (Record.empty())
+        return Error(NaClBitcodeReader::InvalidRecord,
+                     "Malformed CST_SETTYPE record");
+      if (Record[0] >= TypeList.size())
+        return Error(NaClBitcodeReader::InvalidType,
+                     "Invalid Type ID in CST_SETTYPE record");
+      CurTy = TypeList[Record[0]];
+      continue;  // Skip the ValueList manipulation.
+    case naclbitc::CST_CODE_INTEGER:   // INTEGER: [intval]
+      if (!CurTy->isIntegerTy() || Record.empty())
+        return Error(InvalidRecord, "Invalid CST_INTEGER record");
+      V = ConstantInt::get(CurTy, NaClDecodeSignRotatedValue(Record[0]));
+      break;
+    case naclbitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
+      if (Record.empty())
+        return Error(NaClBitcodeReader::InvalidRecord, "Invalid FLOAT record");
+      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
+        return Error(NaClBitcodeReader::InvalidRecord,
+                     "Unknown type for FLOAT record");
+      break;
+    }
+    }
+
+    ValueList.AssignValue(V, NextCstNo);
+    ++NextCstNo;
+  }
+  return std::error_code();
+}
+
+/// 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.
+std::error_code NaClBitcodeReader::RememberAndSkipFunctionBody() {
+  DEBUG(dbgs() << "-> RememberAndSkipFunctionBody\n");
+  // Get the function we are talking about.
+  if (FunctionsWithBodies.empty())
+    return Error(InsufficientFunctionProtos,
+                 "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(InvalidSkippedBlock, "Unable to skip function block.");
+  DEBUG(dbgs() << "<- RememberAndSkipFunctionBody\n");
+  return std::error_code();
+}
+
+std::error_code NaClBitcodeReader::GlobalCleanup() {
+  // 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);
+  return std::error_code();
+}
+
+FunctionType *NaClBitcodeReader::AddPointerTypesToIntrinsicType(
+    StringRef Name, FunctionType *FTy) {
+  FunctionType *IntrinsicTy = AllowedIntrinsics.getIntrinsicType(Name);
+  if (IntrinsicTy == 0) return FTy;
+
+  Type *IReturnTy = IntrinsicTy->getReturnType();
+  Type *FReturnTy = FTy->getReturnType();
+
+  if (!PNaClABITypeChecker::IsPointerEquivType(IReturnTy, FReturnTy)) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << "Intrinsic return type mismatch for " << Name << ": "
+           << *IReturnTy << " and " << *FReturnTy;
+    report_fatal_error(StrBuf.str());
+  }
+  if (FTy->getNumParams() != IntrinsicTy->getNumParams()) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << "Intrinsic type mistmatch for " << Name << ": "
+           << *FTy << " and " << *IntrinsicTy;
+    report_fatal_error(StrBuf.str());
+  }
+  for (unsigned i = 0; i < FTy->getNumParams(); ++i) {
+    Type *IargTy = IntrinsicTy->getParamType(i);
+    Type *FargTy = FTy->getParamType(i);
+    if (!PNaClABITypeChecker::IsPointerEquivType(IargTy, FargTy)) {
+      std::string Buffer;
+      raw_string_ostream StrBuf(Buffer);
+      StrBuf << "Intrinsic type mismatch for argument " << i << " in "
+             << Name << ": " << *IargTy << " and " << *FargTy;
+      report_fatal_error(StrBuf.str());
+    }
+  }
+  return IntrinsicTy;
+}
+
+void NaClBitcodeReader::AddPointerTypesToIntrinsicParams() {
+  for (unsigned Index = 0, E = ValueList.size(); Index < E; ++Index) {
+    if (Function *Func = dyn_cast<Function>(ValueList[Index])) {
+      if (Func->isIntrinsic()) {
+        FunctionType *FTy = Func->getFunctionType();
+        FunctionType *ITy = AddPointerTypesToIntrinsicType(
+            Func->getName(), FTy);
+        if (ITy == FTy) continue;
+        Function *NewIntrinsic = Function::Create(
+            ITy, GlobalValue::ExternalLinkage, "", TheModule);
+        NewIntrinsic->takeName(Func);
+        ValueList.OverwriteValue(NewIntrinsic, Index);
+        Func->eraseFromParent();
+      }
+    }
+  }
+}
+
+std::error_code NaClBitcodeReader::ParseModule(bool Resume) {
+  DEBUG(dbgs() << "-> ParseModule\n");
+  if (Resume)
+    Stream.JumpToBit(NextUnreadBit);
+  else if (Stream.EnterSubBlock(naclbitc::MODULE_BLOCK_ID))
+    return Error(InvalidRecord, "Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+
+  // Read all the records for this module.
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance(0, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "malformed module block");
+    case NaClBitstreamEntry::EndBlock:
+      DEBUG(dbgs() << "<- ParseModule\n");
+      if (std::error_code EC = GlobalCleanup())
+        return EC;
+      if (!Stream.AtEndOfStream())
+        return Error(InvalidDataAfterModule, "Invalid data after module");
+      return std::error_code();
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      default: {
+        std::string Message;
+        raw_string_ostream StrM(Message);
+        StrM << "Unknown block ID: " << Entry.ID;
+        return Error(InvalidRecord, StrM.str());
+      }
+      case naclbitc::BLOCKINFO_BLOCK_ID:
+        if (Stream.ReadBlockInfoBlock(0))
+          return Error(MalformedBlock, "Malformed BlockInfoBlock");
+        break;
+      case naclbitc::TYPE_BLOCK_ID_NEW:
+        if (std::error_code EC = ParseTypeTable())
+          return EC;
+        break;
+      case naclbitc::GLOBALVAR_BLOCK_ID:
+        if (std::error_code EC = ParseGlobalVars())
+          return EC;
+        break;
+      case naclbitc::VALUE_SYMTAB_BLOCK_ID:
+        if (std::error_code EC = ParseValueSymbolTable())
+          return EC;
+        SeenValueSymbolTable = true;
+        // Now that we know the names of the intrinsics, we can add
+        // pointer types to the intrinsic declarations' types.
+        AddPointerTypesToIntrinsicParams();
+        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 (std::error_code EC = GlobalCleanup())
+            return EC;
+          SeenFirstFunctionBody = true;
+        }
+
+        if (std::error_code EC = RememberAndSkipFunctionBody())
+          return EC;
+
+        // 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();
+          DEBUG(dbgs() << "<- ParseModule\n");
+          return std::error_code();
+        }
+        break;
+      }
+      continue;
+
+    case NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read a record.
+    unsigned Selector = Stream.readRecord(Entry.ID, Record);
+    switch (Selector) {
+    default: {
+      std::string Message;
+      raw_string_ostream StrM(Message);
+      StrM << "Invalid MODULE_CODE: " << Selector;
+      StrM.flush();
+      return Error(InvalidValue, Message);
+    }
+    case naclbitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
+      if (Record.size() < 1)
+        return Error(InvalidRecord, "Malformed MODULE_CODE_VERSION");
+      // Only version #1 is supported for PNaCl. Version #0 is not supported.
+      unsigned module_version = Record[0];
+      if (module_version != 1)
+        return Error(InvalidValue, "Unknown bitstream version!");
+      break;
+    }
+    // FUNCTION:  [type, callingconv, isproto, linkage]
+    case naclbitc::MODULE_CODE_FUNCTION: {
+      if (Record.size() < 4)
+        return Error(InvalidRecord, "Invalid MODULE_CODE_FUNCTION record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty)
+        return Error(InvalidType, "Invalid MODULE_CODE_FUNCTION record");
+      FunctionType *FTy = dyn_cast<FunctionType>(Ty);
+      if (!FTy)
+        return Error(InvalidType,
+                     "Function not declared with a function type!");
+
+      Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
+                                        "", TheModule);
+
+      CallingConv::ID CallingConv;
+      if (!naclbitc::DecodeCallingConv(Record[1], CallingConv))
+        return Error(InvalidValue,
+                     "PNaCl bitcode contains invalid calling conventions.");
+      Func->setCallingConv(CallingConv);
+      bool isProto = Record[2];
+      GlobalValue::LinkageTypes Linkage;
+      if (!naclbitc::DecodeLinkage(Record[3], Linkage))
+        return Error(InvalidValue, "Unknown linkage type");
+      Func->setLinkage(Linkage);
+      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) {
+        Func->setIsMaterializable(true);
+        FunctionsWithBodies.push_back(Func);
+        if (LazyStreamer) DeferredFunctionInfo[Func] = 0;
+      }
+      break;
+    }
+    }
+    Record.clear();
+  }
+  return std::error_code();
+}
+
+const char *llvm::PNaClDataLayout =
+    "e-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-"
+    "f32:32:32-f64:64:64-p:32:32:32-v128:32:32";
+
+std::error_code NaClBitcodeReader::ParseBitcodeInto(Module *M) {
+  TheModule = 0;
+
+  // PNaCl does not support different DataLayouts in pexes, so we
+  // implicitly set the DataLayout to the following default.
+  //
+  // This is not usually needed by the backend, but it might be used
+  // by IR passes that the PNaCl translator runs.  We set this in the
+  // reader rather than in pnacl-llc so that 'opt' will also use the
+  // correct DataLayout if it is run on a pexe.
+  M->setDataLayout(PNaClDataLayout);
+
+  if (std::error_code EC = InitStream())
+    return EC;
+
+  // We expect a number of well-defined blocks, though we don't necessarily
+  // need to understand them all.
+  while (1) {
+    if (Stream.AtEndOfStream())
+      return std::error_code();
+
+    NaClBitstreamEntry Entry =
+        Stream.advance(NaClBitstreamCursor::AF_DontAutoprocessAbbrevs, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "malformed module file");
+    case NaClBitstreamEntry::EndBlock:
+      return std::error_code();
+
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      case naclbitc::MODULE_BLOCK_ID:
+        // Reject multiple MODULE_BLOCK's in a single bitstream.
+        if (TheModule)
+          return Error(InvalidMultipleBlocks,
+                       "Multiple MODULE_BLOCKs in same stream");
+        TheModule = M;
+        if (std::error_code EC = ParseModule(false))
+          return EC;
+        if (LazyStreamer)
+          return std::error_code();
+        break;
+      default:
+        return Error(InvalidBlock, "Invalid top-level block found.");
+        break;
+      }
+      continue;
+    case NaClBitstreamEntry::Record:
+      // There should be no records in the top-level of blocks.
+      return Error(InvalidRecord, "Invalid record at top-level");
+    }
+  }
+}
+
+// Returns true if error occured installing I into BB.
+std::error_code NaClBitcodeReader::InstallInstruction(
+    BasicBlock *BB, Instruction *I) {
+  // Add instruction to end of current BB.  If there is no current BB, reject
+  // this file.
+  if (BB == 0) {
+    delete I;
+    return Error(InvalidInstructionWithNoBB,
+                 "Instruction with no BB, can't install");
+  }
+  BB->getInstList().push_back(I);
+  return std::error_code();
+}
+
+CastInst *
+NaClBitcodeReader::CreateCast(unsigned BBIndex, Instruction::CastOps Op,
+                              Type *CT, Value *V, bool DeferInsertion) {
+  if (BBIndex >= FunctionBBs.size())
+    report_fatal_error("CreateCast on unknown basic block");
+  BasicBlockInfo &BBInfo = FunctionBBs[BBIndex];
+  NaClBitcodeReaderCast ModeledCast(Op, CT, V);
+  CastInst *Cast = BBInfo.CastMap[ModeledCast];
+  if (Cast == NULL) {
+    Cast = CastInst::Create(Op, V, CT);
+    BBInfo.CastMap[ModeledCast] = Cast;
+    if (DeferInsertion) {
+      BBInfo.PhiCasts.push_back(Cast);
+    }
+  }
+  if (!DeferInsertion && Cast->getParent() == 0) {
+    InstallInstruction(BBInfo.BB, Cast);
+  }
+  return Cast;
+}
+
+Value *NaClBitcodeReader::ConvertOpToScalar(Value *Op, unsigned BBIndex,
+                                            bool DeferInsertion) {
+  if (Op->getType()->isPointerTy()) {
+    return CreateCast(BBIndex, Instruction::PtrToInt, IntPtrType, Op,
+                      DeferInsertion);
+  }
+  return Op;
+}
+
+Value *NaClBitcodeReader::ConvertOpToType(Value *Op, Type *T,
+                                          unsigned BBIndex) {
+  Type *OpTy = Op->getType();
+  if (OpTy == T) return Op;
+
+  if (OpTy->isPointerTy()) {
+    if (T == IntPtrType) {
+      return ConvertOpToScalar(Op, BBIndex);
+    } else {
+      return CreateCast(BBIndex, Instruction::BitCast, T, Op);
+    }
+  } else if (OpTy == IntPtrType) {
+    return CreateCast(BBIndex, Instruction::IntToPtr, T, Op);
+  }
+
+  std::string Message;
+  raw_string_ostream StrM(Message);
+  StrM << "Can't convert " << *Op << " to type " << *T << "\n";
+  report_fatal_error(StrM.str());
+}
+
+/// ParseFunctionBody - Lazily parse the specified function body block.
+std::error_code NaClBitcodeReader::ParseFunctionBody(Function *F) {
+  DEBUG(dbgs() << "-> ParseFunctionBody\n");
+  if (Stream.EnterSubBlock(naclbitc::FUNCTION_BLOCK_ID))
+    return Error(InvalidRecord, "Malformed block record");
+
+  unsigned ModuleValueListSize = ValueList.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;
+
+  // Read all the records.
+  SmallVector<uint64_t, 64> Record;
+  while (1) {
+    NaClBitstreamEntry Entry = Stream.advance(0, nullptr);
+
+    switch (Entry.Kind) {
+    case NaClBitstreamEntry::Error:
+      return Error(MalformedBlock, "Bitcode error in function block");
+    case NaClBitstreamEntry::EndBlock:
+      goto OutOfRecordLoop;
+
+    case NaClBitstreamEntry::SubBlock:
+      switch (Entry.ID) {
+      default:
+        return Error(InvalidBlock, "Invalid block in function block");
+        break;
+      case naclbitc::CONSTANTS_BLOCK_ID:
+        if (std::error_code EC = ParseConstants())
+          return EC;
+        NextValueNo = ValueList.size();
+        break;
+      case naclbitc::VALUE_SYMTAB_BLOCK_ID:
+        if (PNaClAllowLocalSymbolTables) {
+          if (std::error_code EC = ParseValueSymbolTable())
+            return EC;
+        } else {
+          return Error(InvalidRecord, "Local value symbol tables not allowed");
+        }
+        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
+      std::string Message;
+      raw_string_ostream StrM(Message);
+      StrM << "Unknown instruction record: <" << BitCode;
+      for (unsigned I = 0, E = Record.size(); I != E; ++I) {
+        StrM << " " << Record[I];
+      }
+      StrM << ">";
+      return Error(InvalidRecord, StrM.str());
+    }
+
+    case naclbitc::FUNC_CODE_DECLAREBLOCKS:     // DECLAREBLOCKS: [nblocks]
+      if (Record.size() != 1 || Record[0] == 0)
+        return Error(InvalidRecord, "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) {
+        BasicBlockInfo &BBInfo = FunctionBBs[i];
+        BBInfo.BB = BasicBlock::Create(Context, "", F);
+      }
+      CurBB = FunctionBBs.at(0).BB;
+      continue;
+
+    case naclbitc::FUNC_CODE_INST_BINOP: {
+      // BINOP: [opval, opval, opcode[, flags]]
+      // Note: Only old PNaCl bitcode files may contain flags. If
+      // they are found, we ignore them.
+      unsigned OpNum = 0;
+      Value *LHS, *RHS;
+      if (popValue(Record, &OpNum, NextValueNo, &LHS) ||
+          popValue(Record, &OpNum, NextValueNo, &RHS) ||
+          OpNum+1 > Record.size())
+        return Error(InvalidRecord, "Invalid BINOP record");
+
+      LHS = ConvertOpToScalar(LHS, CurBBNo);
+      RHS = ConvertOpToScalar(RHS, CurBBNo);
+
+      Instruction::BinaryOps Opc;
+      if (!naclbitc::DecodeBinaryOpcode(Record[OpNum++], LHS->getType(), Opc))
+        return Error(InvalidValue, "Invalid binary opcode in BINOP record");
+      I = BinaryOperator::Create(Opc, LHS, RHS);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, destty, castopc]
+      unsigned OpNum = 0;
+      Value *Op;
+      if (popValue(Record, &OpNum, NextValueNo, &Op) ||
+          OpNum+2 != Record.size())
+        return Error(InvalidRecord, "Invalid CAST record: bad record size");
+
+      Type *ResTy = getTypeByID(Record[OpNum]);
+      if (ResTy == 0)
+        return Error(InvalidType, "Invalid CAST record: bad type ID");
+      Instruction::CastOps Opc;
+      if (!naclbitc::DecodeCastOpcode(Record[OpNum+1], Opc)) {
+        return Error(InvalidValue, "Invalid CAST record: bad opcode");
+      }
+
+      // If a ptrtoint cast was elided on the argument of the cast,
+      // add it back. Note: The casts allowed here should match the
+      // casts in NaClValueEnumerator::ExpectsScalarValue.
+      switch (Opc) {
+      case Instruction::Trunc:
+      case Instruction::ZExt:
+      case Instruction::SExt:
+      case Instruction::UIToFP:
+      case Instruction::SIToFP:
+        Op = ConvertOpToScalar(Op, CurBBNo);
+        break;
+      default:
+        break;
+      }
+
+      I = CastInst::Create(Opc, Op, ResTy);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_VSELECT: {// VSELECT: [opval, opval, pred]
+      // new form of select
+      // handles select i1 or select [N x i1]
+      unsigned OpNum = 0;
+      Value *TrueVal, *FalseVal, *Cond;
+      if (popValue(Record, &OpNum, NextValueNo, &TrueVal) ||
+          popValue(Record, &OpNum, NextValueNo, &FalseVal) ||
+          popValue(Record, &OpNum, NextValueNo, &Cond) ||
+          OpNum != Record.size())
+        return Error(InvalidRecord, "Invalid SELECT record");
+
+      TrueVal = ConvertOpToScalar(TrueVal, CurBBNo);
+      FalseVal = ConvertOpToScalar(FalseVal, CurBBNo);
+
+      // 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(InvalidTypeForValue,
+                       "Invalid SELECT vector condition type");
+      } else {
+        // expect i1
+        if (Cond->getType() != Type::getInt1Ty(Context))
+          return Error(InvalidTypeForValue, "Invalid SELECT condition type");
+      }
+
+      I = SelectInst::Create(Cond, TrueVal, FalseVal);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_EXTRACTELT: { // EXTRACTELT: [opval, opval]
+      unsigned OpNum = 0;
+      Value *Vec, *Idx;
+      if (popValue(Record, &OpNum, NextValueNo, &Vec) ||
+          popValue(Record, &OpNum, NextValueNo, &Idx) || OpNum != Record.size())
+        return Error(InvalidRecord, "Invalid EXTRACTELEMENT record");
+
+      // expect i32
+      if (Idx->getType() != Type::getInt32Ty(Context))
+        return Error(InvalidTypeForValue, "Invalid EXTRACTELEMENT index type");
+
+      I = ExtractElementInst::Create(Vec, Idx);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_INSERTELT: { // INSERTELT: [opval,opval,opval]
+      unsigned OpNum = 0;
+      Value *Vec, *Elt, *Idx;
+      if (popValue(Record, &OpNum, NextValueNo, &Vec) ||
+          popValue(Record, &OpNum, NextValueNo, &Elt) ||
+          popValue(Record, &OpNum, NextValueNo, &Idx) || OpNum != Record.size())
+        return Error(InvalidRecord, "Invalid INSERTELEMENT record");
+
+      // expect vector type
+      if (!isa<VectorType>(Vec->getType()))
+        return Error(InvalidTypeForValue, "Invalid INSERTELEMENT vector type");
+      // match vector and element types
+      if (cast<VectorType>(Vec->getType())->getElementType() != Elt->getType())
+        return Error(InvalidTypeForValue,
+                     "Mismatched INSERTELEMENT vector and element type");
+      // expect i32
+      if (Idx->getType() != Type::getInt32Ty(Context))
+        return Error(InvalidTypeForValue, "Invalid INSERTELEMENT index type");
+
+      I = InsertElementInst::Create(Vec, Elt, Idx);
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_CMP2: { // CMP2: [opval, opval, pred]
+      // FCmp/ICmp returning bool or vector of bool
+
+      unsigned OpNum = 0;
+      Value *LHS, *RHS;
+      if (popValue(Record, &OpNum, NextValueNo, &LHS) ||
+          popValue(Record, &OpNum, NextValueNo, &RHS) ||
+          OpNum+1 != Record.size())
+        return Error(InvalidRecord, "Invalid CMP record");
+
+      LHS = ConvertOpToScalar(LHS, CurBBNo);
+      RHS = ConvertOpToScalar(RHS, CurBBNo);
+
+      CmpInst::Predicate Predicate;
+      if (LHS->getType()->isFPOrFPVectorTy()) {
+        if (!naclbitc::DecodeFcmpPredicate(Record[OpNum], Predicate))
+          return Error(
+              InvalidValue,
+              "PNaCl bitcode contains invalid floating comparison predicate");
+        I = new FCmpInst(Predicate, LHS, RHS);
+      } else {
+        if (!naclbitc::DecodeIcmpPredicate(Record[OpNum], Predicate))
+          return Error(
+              InvalidValue,
+              "PNaCl bitcode contains invalid integer comparison predicate");
+        I = new ICmpInst(Predicate, LHS, RHS);
+      }
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_RET: // RET: [opval<optional>]
+      {
+        unsigned Size = Record.size();
+        if (Size == 0) {
+          I = ReturnInst::Create(Context);
+          break;
+        }
+
+        unsigned OpNum = 0;
+        Value *Op = NULL;
+        if (popValue(Record, &OpNum, NextValueNo, &Op))
+          return Error(InvalidRecord, "Invalid RET record");
+        if (OpNum != Record.size())
+          return Error(InvalidRecord, "Invalid RET record");
+
+        I = ReturnInst::Create(Context, ConvertOpToScalar(Op, CurBBNo));
+        break;
+      }
+    case naclbitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
+      if (Record.size() != 1 && Record.size() != 3)
+        return Error(InvalidRecord, "Invalid BR record");
+      BasicBlock *TrueDest = getBasicBlock(Record[0]);
+      if (TrueDest == 0)
+        return Error(InvalidRecord, "Invalid BR record");
+
+      if (Record.size() == 1) {
+        I = BranchInst::Create(TrueDest);
+      }
+      else {
+        BasicBlock *FalseDest = getBasicBlock(Record[1]);
+        Value *Cond = getValue(Record, 2, NextValueNo);
+        if (FalseDest == 0 || Cond == 0)
+          return Error(InvalidValue, "Invalid BR record");
+        I = BranchInst::Create(TrueDest, FalseDest, Cond);
+      }
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
+      if (Record.size() < 4)
+        return Error(InvalidRecord, "Invalid SWITCH record");
+      Type *OpTy = getTypeByID(Record[0]);
+      unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
+      if (ValueBitWidth > 64)
+        return Error(InvalidValue,
+                     "Wide integers are not supported in PNaCl bitcode");
+
+      Value *Cond = getValue(Record, 1, NextValueNo);
+      BasicBlock *Default = getBasicBlock(Record[2]);
+      if (OpTy == 0 || Cond == 0 || Default == 0)
+        return Error(InvalidRecord, "Invalid SWITCH record");
+
+      Cond = ConvertOpToScalar(Cond, CurBBNo);
+      unsigned NumCases = Record[3];
+
+      SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
+
+      unsigned CurIdx = 4;
+      for (unsigned i = 0; i != NumCases; ++i) {
+        // The PNaCl bitcode format has vestigial support for case
+        // ranges, but we no longer support reading them because
+        // no-one produced them.
+        // See https://code.google.com/p/nativeclient/issues/detail?id=3758
+        unsigned NumItems = Record[CurIdx++];
+        bool isSingleNumber = Record[CurIdx++];
+        if (NumItems != 1 || !isSingleNumber)
+          return Error(InvalidRecord,
+                       "Case ranges are not supported in PNaCl bitcode");
+
+        APInt CaseValue(ValueBitWidth,
+                        NaClDecodeSignRotatedValue(Record[CurIdx++]));
+        BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
+        SI->addCase(ConstantInt::get(Context, CaseValue), DestBB);
+      }
+      I = SI;
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
+      I = new UnreachableInst(Context);
+      break;
+    case naclbitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
+      if (Record.size() < 1 || ((Record.size()-1)&1))
+        return Error(InvalidRecord, "Invalid PHI record");
+      Type *Ty = getTypeByID(Record[0]);
+      if (!Ty) return Error(InvalidType, "Invalid PHI record");
+
+      PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
+
+      for (unsigned i = 0, e = Record.size()-1; i != e; i += 2) {
+        Value *V;
+        // With relative value IDs, it is possible that operands have
+        // negative IDs (for forward references).  Use a signed VBR
+        // representation to keep the encoding small.
+        V = getValueSigned(Record, 1+i, NextValueNo);
+        unsigned BBIndex = Record[2+i];
+        BasicBlock *BB = getBasicBlock(BBIndex);
+        if (!V || !BB)
+          return Error(InvalidValue, "Invalid PHI record");
+        if (Ty == IntPtrType) {
+          // Delay installing scalar casts until all instructions of
+          // the function are rendered. This guarantees that we insert
+          // the conversion just before the incoming edge (or use an
+          // existing conversion if already installed).
+          V = ConvertOpToScalar(V, BBIndex, /* DeferInsertion = */ true);
+        }
+        PN->addIncoming(V, BB);
+      }
+      I = PN;
+      break;
+    }
+
+    case naclbitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [op, align]
+      if (Record.size() != 2)
+        return Error(InvalidRecord, "Invalid ALLOCA record");
+      Value *Size;
+      unsigned OpNum = 0;
+      if (popValue(Record, &OpNum, NextValueNo, &Size))
+        return Error(InvalidRecord, "Invalid ALLOCA record");
+      unsigned Alignment;
+      if (std::error_code EC = getAlignmentValue(Record[1], Alignment))
+        return EC;
+      I = new AllocaInst(Type::getInt8Ty(Context), Size, Alignment);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_LOAD: {
+      // LOAD: [op, align, ty]
+      unsigned OpNum = 0;
+      Value *Op;
+      if (popValue(Record, &OpNum, NextValueNo, &Op) ||
+          Record.size() != 3)
+        return Error(InvalidRecord, "Invalid LOAD record");
+
+      // Add pointer cast to op.
+      Type *T = getTypeByID(Record[2]);
+      if (T == nullptr)
+        return Error(InvalidType, "Invalid type for load instruction");
+      Op = ConvertOpToType(Op, T->getPointerTo(), CurBBNo);
+      if (Op == nullptr)
+        return Error(InvalidTypeForValue, "Can't convert cast to type");
+      unsigned Alignment;
+      if (std::error_code EC = getAlignmentValue(Record[OpNum], Alignment))
+        return EC;
+      I = new LoadInst(Op, "", false, Alignment);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_STORE: {
+      // STORE: [ptr, val, align]
+      unsigned OpNum = 0;
+      Value *Val, *Ptr;
+      if (popValue(Record, &OpNum, NextValueNo, &Ptr) ||
+          popValue(Record, &OpNum, NextValueNo, &Val) ||
+          OpNum+1 != Record.size())
+        return Error(InvalidRecord, "Invalid STORE record");
+      Val = ConvertOpToScalar(Val, CurBBNo);
+      Ptr = ConvertOpToType(Ptr, Val->getType()->getPointerTo(), CurBBNo);
+      if (Ptr == nullptr)
+        return Error(InvalidTypeForValue, "Can't convert cast to type");
+      unsigned Alignment;
+      if (std::error_code EC = getAlignmentValue(Record[OpNum], Alignment))
+       return EC;
+      I = new StoreInst(Val, Ptr, false, Alignment);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_CALL:
+    case naclbitc::FUNC_CODE_INST_CALL_INDIRECT: {
+      // CALL: [cc, fnid, arg0, arg1...]
+      // CALL_INDIRECT: [cc, fnid, returnty, args...]
+      if ((Record.size() < 2) ||
+          (BitCode == naclbitc::FUNC_CODE_INST_CALL_INDIRECT &&
+           Record.size() < 3))
+        return Error(InvalidRecord, "Invalid CALL record");
+
+      unsigned CCInfo = Record[0];
+
+      unsigned OpNum = 1;
+      Value *Callee;
+      if (popValue(Record, &OpNum, NextValueNo, &Callee))
+        return Error(InvalidRecord, "Invalid CALL record");
+
+      // Build function type for call.
+      FunctionType *FTy = 0;
+      Type *ReturnType = 0;
+      if (BitCode == naclbitc::FUNC_CODE_INST_CALL_INDIRECT) {
+        // Callee type has been elided, add back in.
+        ReturnType = getTypeByID(Record[2]);
+        ++OpNum;
+      } else {
+        // Get type signature from callee.
+        if (PointerType *OpTy = dyn_cast<PointerType>(Callee->getType())) {
+          FTy = dyn_cast<FunctionType>(OpTy->getElementType());
+        }
+        if (FTy == 0)
+          return Error(InvalidType, "Invalid type for CALL record");
+      }
+
+      unsigned NumParams = Record.size() - OpNum;
+      if (FTy && NumParams != FTy->getNumParams())
+        return Error(InvalidRecord, "Invalid CALL record");
+
+      // Process call arguments.
+      SmallVector<Value*, 6> Args;
+      for (unsigned Index = 0; Index < NumParams; ++Index) {
+        Value *Arg;
+        if (popValue(Record, &OpNum, NextValueNo, &Arg)) {
+          std::string Buffer;
+          raw_string_ostream StrBuf(Buffer);
+          StrBuf << "Invalid call argument: Index " << Index;
+          return Error(InvalidValue, StrBuf.str());
+        }
+        if (FTy) {
+          // Add a cast, to a pointer type if necessary, in case this
+          // is an intrinsic call that takes a pointer argument.
+          Arg = ConvertOpToType(Arg, FTy->getParamType(Index), CurBBNo);
+        } else {
+          Arg = ConvertOpToScalar(Arg, CurBBNo);
+        }
+        if (Arg == nullptr) {
+          std::string Buffer;
+          raw_string_ostream StrBuf(Buffer);
+          StrBuf << "Unable to cast call argument to parameter type: " << Index;
+          return Error(InvalidValue, StrBuf.str());
+        }
+        Args.push_back(Arg);
+      }
+      if (FTy == nullptr) {
+        // Reconstruct the function type and cast the function pointer
+        // to it.
+        SmallVector<Type*, 6> ArgTypes;
+        for (const auto Arg : Args) {
+          ArgTypes.push_back(Arg->getType());
+        }
+        FTy = FunctionType::get(ReturnType, ArgTypes, false);
+        Callee = ConvertOpToType(Callee, FTy->getPointerTo(), CurBBNo);
+      }
+
+      // Construct call.
+      I = CallInst::Create(Callee, Args);
+      CallingConv::ID CallingConv;
+      if (!naclbitc::DecodeCallingConv(CCInfo>>1, CallingConv))
+        return Error(InvalidValue,
+                     "PNaCl bitcode contains invalid calling conventions.");
+      cast<CallInst>(I)->setCallingConv(CallingConv);
+      cast<CallInst>(I)->setTailCall(CCInfo & 1);
+      break;
+    }
+    case naclbitc::FUNC_CODE_INST_FORWARDTYPEREF:
+      // Build corresponding forward reference.
+      if (Record.size() != 2 ||
+          ValueList.createValueFwdRef(Record[0], getTypeByID(Record[1])))
+        return Error(InvalidRecord, "Invalid FORWARDTYPEREF record");
+      continue;
+    }
+
+    if (std::error_code EC = InstallInstruction(CurBB, I))
+      return EC;
+
+    // If this was a terminator instruction, move to the next block.
+    if (isa<TerminatorInst>(I)) {
+      ++CurBBNo;
+      CurBB = getBasicBlock(CurBBNo);
+    }
+
+    // Non-void values get registered in the value table for future use.
+    if (I && !I->getType()->isVoidTy()) {
+      Value *NewVal = I;
+      if (NewVal->getType()->isPointerTy() &&
+          ValueList.getValueFwdRef(NextValueNo)) {
+        // Forward-referenced values cannot have pointer type.
+        NewVal = ConvertOpToScalar(NewVal, CurBBNo);
+      }
+      ValueList.AssignValue(NewVal, NextValueNo++);
+    }
+  }
+
+OutOfRecordLoop:
+
+  // Add PHI conversions to corresponding incoming block, if not
+  // already in the block. Also clear all conversions after fixing
+  // PHI conversions.
+  for (unsigned I = 0, NumBBs = FunctionBBs.size(); I < NumBBs; ++I) {
+    BasicBlockInfo &BBInfo = FunctionBBs[I];
+    std::vector<CastInst*> &PhiCasts = BBInfo.PhiCasts;
+    for (std::vector<CastInst*>::iterator Iter = PhiCasts.begin(),
+           IterEnd = PhiCasts.end(); Iter != IterEnd; ++Iter) {
+      CastInst *Cast = *Iter;
+      if (Cast->getParent() == 0) {
+        BasicBlock *BB = BBInfo.BB;
+        BB->getInstList().insert(BB->getTerminator(), Cast);
+      }
+    }
+    PhiCasts.clear();
+    BBInfo.CastMap.clear();
+  }
+
+  // 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(InvalidValue, "Never resolved value found in function!");
+    }
+  }
+
+  // Trim the value list down to the size it was before we parsed this function.
+  ValueList.shrinkTo(ModuleValueListSize);
+  FunctionBBs.clear();
+  DEBUG(dbgs() << "-> ParseFunctionBody\n");
+  return std::error_code();
+}
+
+/// FindFunctionInStream - Find the function body in the bitcode stream
+std::error_code NaClBitcodeReader::FindFunctionInStream(
+    Function *F,
+    DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator) {
+  while (DeferredFunctionInfoIterator->second == 0) {
+    if (Stream.AtEndOfStream())
+      return Error(CouldNotFindFunctionInStream,
+                   "Could not find Function in stream");
+    // ParseModule will parse the next body in the stream and set its
+    // position in the DeferredFunctionInfo map.
+    if (std::error_code EC = ParseModule(true))
+      return EC;
+  }
+  return std::error_code();
+}
+
+//===----------------------------------------------------------------------===//
+// GVMaterializer implementation
+//===----------------------------------------------------------------------===//
+
+void NaClBitcodeReader::releaseBuffer() { Buffer.release(); }
+
+std::error_code NaClBitcodeReader::materialize(GlobalValue *GV) {
+  Function *F = dyn_cast<Function>(GV);
+  // If it's not a function or is already material, ignore the request.
+  if (!F || !F->isMaterializable())
+    return std::error_code();
+
+  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 (std::error_code EC = FindFunctionInStream(F, DFII)) {
+      return EC;
+    }
+  }
+
+  // Move the bit stream to the saved position of the deferred function body.
+  Stream.JumpToBit(DFII->second);
+
+  if (std::error_code EC = ParseFunctionBody(F))
+    return EC;
+  F->setIsMaterializable(false);
+
+  // 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 std::error_code();
+}
+
+bool NaClBitcodeReader::isDematerializable(const GlobalValue *GV) const {
+  const Function *F = dyn_cast<Function>(GV);
+  if (!F || F->isDeclaration())
+    return false;
+  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->dropAllReferences();
+  F->setIsMaterializable(true);
+}
+
+
+std::error_code NaClBitcodeReader::MaterializeModule(Module *M) {
+  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()) {
+      if (std::error_code EC = materialize(F))
+        return EC;
+    }
+  }
+
+  // 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 std::error_code();
+}
+
+std::error_code NaClBitcodeReader::InitStream() {
+  if (LazyStreamer)
+    return InitLazyStream();
+  return InitStreamFromBuffer();
+}
+
+std::error_code NaClBitcodeReader::InitStreamFromBuffer() {
+  const unsigned char *BufPtr = (const unsigned char*)Buffer->getBufferStart();
+  const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
+
+  if (Buffer->getBufferSize() & 3)
+    return Error(InvalidBitstream,
+                 "Bitcode stream should be a multiple of 4 bytes in length");
+
+  if (Header.Read(BufPtr, BufEnd))
+    return Error(InvalidBitstream, Header.Unsupported());
+
+  StreamFile.reset(new NaClBitstreamReader(BufPtr, BufEnd));
+  Stream.init(StreamFile.get());
+
+  if (AcceptHeader())
+    return Error(InvalidBitstream, Header.Unsupported());
+  return std::error_code();
+}
+
+std::error_code NaClBitcodeReader::InitLazyStream() {
+  if (Header.Read(LazyStreamer))
+    return Error(InvalidBitstream, Header.Unsupported());
+
+  StreamFile.reset(new NaClBitstreamReader(LazyStreamer,
+                                           Header.getHeaderSize()));
+  Stream.init(StreamFile.get());
+  if (AcceptHeader())
+    return Error(InvalidBitstream, Header.Unsupported());
+  return std::error_code();
+}
+
+//===----------------------------------------------------------------------===//
+// External interface
+//===----------------------------------------------------------------------===//
+
+/// \brief Get a lazy one-at-time loading module from bitcode.
+///
+/// This isn't always used in a lazy context.  In particular, it's also used by
+/// \a NaClParseBitcodeFile(). Compared to the upstream LLVM bitcode reader,
+/// NaCl does not support BlockAddresses, so it does not need to materialize
+/// forward-referenced functions from block address references.
+ErrorOr<Module *> llvm::getNaClLazyBitcodeModule(
+    std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext& Context,
+    raw_ostream *Verbose, bool AcceptSupportedOnly) {
+  Module *M = new Module(Buffer->getBufferIdentifier(), Context);
+  NaClBitcodeReader *R =
+      new NaClBitcodeReader(Buffer.get(), Context, Verbose, AcceptSupportedOnly);
+  M->setMaterializer(R);
+
+  auto cleanupOnError = [&](std::error_code EC) {
+    R->releaseBuffer(); // Never take ownership on error.
+    delete M;  // Also deletes R.
+    return EC;
+  };
+
+  if (std::error_code EC = R->ParseBitcodeInto(M))
+    return cleanupOnError(EC);
+
+  Buffer.release(); // The BitcodeReader owns it now.
+  return M;
+}
+
+
+Module *llvm::getNaClStreamedBitcodeModule(const std::string &name,
+                                           StreamingMemoryObject *Streamer,
+                                           LLVMContext &Context,
+                                           raw_ostream *Verbose,
+                                           std::string *ErrMsg,
+                                           bool AcceptSupportedOnly) {
+  Module *M = new Module(name, Context);
+  NaClBitcodeReader *R =
+      new NaClBitcodeReader(Streamer, Context, Verbose,
+                            AcceptSupportedOnly);
+  M->setMaterializer(R);
+  if (std::error_code EC = R->ParseBitcodeInto(M)) {
+    if (ErrMsg)
+      *ErrMsg = EC.message();
+    delete M;  // Also deletes R.
+    return nullptr;
+  }
+
+  return M;
+}
+
+ErrorOr<Module *> llvm::NaClParseBitcodeFile(
+    MemoryBufferRef Buffer, LLVMContext& Context, raw_ostream *Verbose,
+    bool AcceptSupportedOnly){
+  std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
+  ErrorOr<Module *> ModuleOrErr =
+      getNaClLazyBitcodeModule(std::move(Buf), Context, Verbose, AcceptSupportedOnly);
+  if (!ModuleOrErr)
+    return ModuleOrErr;
+  Module *M = ModuleOrErr.get();
+  // Read in the entire module, and destroy the NaClBitcodeReader.
+  if (std::error_code EC = M->materializeAllPermanently()) {
+    delete M;
+    return EC;
+  }
+
+  // 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;
+}