//===- BitcodeReader.cpp - Internal BitcodeReader 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/ReaderWriter.h"
#include "BitcodeReader.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/AutoUpgrade.h"
#include "llvm/Bitcode/LLVMBitCodes.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.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"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

enum {
  SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
};

void BitcodeReader::materializeForwardReferencedFunctions() {
  while (!BlockAddrFwdRefs.empty()) {
    Function *F = BlockAddrFwdRefs.begin()->first;
    F->Materialize();
  }
}

void BitcodeReader::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;
  }
}

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 bitc::CAST_TRUNC   : return Instruction::Trunc;
  case bitc::CAST_ZEXT    : return Instruction::ZExt;
  case bitc::CAST_SEXT    : return Instruction::SExt;
  case bitc::CAST_FPTOUI  : return Instruction::FPToUI;
  case bitc::CAST_FPTOSI  : return Instruction::FPToSI;
  case bitc::CAST_UITOFP  : return Instruction::UIToFP;
  case bitc::CAST_SITOFP  : return Instruction::SIToFP;
  case bitc::CAST_FPTRUNC : return Instruction::FPTrunc;
  case bitc::CAST_FPEXT   : return Instruction::FPExt;
  case bitc::CAST_PTRTOINT: return Instruction::PtrToInt;
  case bitc::CAST_INTTOPTR: return Instruction::IntToPtr;
  case bitc::CAST_BITCAST : return Instruction::BitCast;
  case bitc::CAST_ADDRSPACECAST: return Instruction::AddrSpaceCast;
  }
}
static int GetDecodedBinaryOpcode(unsigned Val, Type *Ty) {
  switch (Val) {
  default: return -1;
  case bitc::BINOP_ADD:
    return Ty->isFPOrFPVectorTy() ? Instruction::FAdd : Instruction::Add;
  case bitc::BINOP_SUB:
    return Ty->isFPOrFPVectorTy() ? Instruction::FSub : Instruction::Sub;
  case bitc::BINOP_MUL:
    return Ty->isFPOrFPVectorTy() ? Instruction::FMul : Instruction::Mul;
  case bitc::BINOP_UDIV: return Instruction::UDiv;
  case bitc::BINOP_SDIV:
    return Ty->isFPOrFPVectorTy() ? Instruction::FDiv : Instruction::SDiv;
  case bitc::BINOP_UREM: return Instruction::URem;
  case bitc::BINOP_SREM:
    return Ty->isFPOrFPVectorTy() ? Instruction::FRem : Instruction::SRem;
  case bitc::BINOP_SHL:  return Instruction::Shl;
  case bitc::BINOP_LSHR: return Instruction::LShr;
  case bitc::BINOP_ASHR: return Instruction::AShr;
  case bitc::BINOP_AND:  return Instruction::And;
  case bitc::BINOP_OR:   return Instruction::Or;
  case bitc::BINOP_XOR:  return Instruction::Xor;
  }
}

static AtomicRMWInst::BinOp GetDecodedRMWOperation(unsigned Val) {
  switch (Val) {
  default: return AtomicRMWInst::BAD_BINOP;
  case bitc::RMW_XCHG: return AtomicRMWInst::Xchg;
  case bitc::RMW_ADD: return AtomicRMWInst::Add;
  case bitc::RMW_SUB: return AtomicRMWInst::Sub;
  case bitc::RMW_AND: return AtomicRMWInst::And;
  case bitc::RMW_NAND: return AtomicRMWInst::Nand;
  case bitc::RMW_OR: return AtomicRMWInst::Or;
  case bitc::RMW_XOR: return AtomicRMWInst::Xor;
  case bitc::RMW_MAX: return AtomicRMWInst::Max;
  case bitc::RMW_MIN: return AtomicRMWInst::Min;
  case bitc::RMW_UMAX: return AtomicRMWInst::UMax;
  case bitc::RMW_UMIN: return AtomicRMWInst::UMin;
  }
}

static AtomicOrdering GetDecodedOrdering(unsigned Val) {
  switch (Val) {
  case bitc::ORDERING_NOTATOMIC: return NotAtomic;
  case bitc::ORDERING_UNORDERED: return Unordered;
  case bitc::ORDERING_MONOTONIC: return Monotonic;
  case bitc::ORDERING_ACQUIRE: return Acquire;
  case bitc::ORDERING_RELEASE: return Release;
  case bitc::ORDERING_ACQREL: return AcquireRelease;
  default: // Map unknown orderings to sequentially-consistent.
  case bitc::ORDERING_SEQCST: return SequentiallyConsistent;
  }
}

static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
  switch (Val) {
  case bitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
  default: // Map unknown scopes to cross-thread.
  case bitc::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 BitcodeReaderValueList::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 *BitcodeReaderValueList::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 *BitcodeReaderValueList::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 BitcodeReaderValueList::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 BitcodeReaderMDValueList::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 *BitcodeReaderMDValueList::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, None);
  MDValuePtrs[Idx] = V;
  return V;
}

Type *BitcodeReader::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));
}

error_code BitcodeReader::ParseAttributeBlock() {
  if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
    return Error(InvalidRecord);

  if (!MAttributes.empty())
    return Error(InvalidMultipleBlocks);

  SmallVector<uint64_t, 64> Record;

  SmallVector<AttributeSet, 8> Attrs;

  // Read all the records.
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      return error_code::success();
    case BitstreamEntry::Record:
      // The interesting case.
      break;
    }

    // Read a record.
    Record.clear();
    switch (Stream.readRecord(Entry.ID, Record)) {
    default:  // Default behavior: ignore.
      break;
    case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
      // FIXME: Remove in 4.0.
      if (Record.size() & 1)
        return Error(InvalidRecord);

      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 bitc::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;
    }
    }
  }
}

// Returns Attribute::None on unrecognized codes.
static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
  switch (Code) {
  default:
    return Attribute::None;
  case bitc::ATTR_KIND_ALIGNMENT:
    return Attribute::Alignment;
  case bitc::ATTR_KIND_ALWAYS_INLINE:
    return Attribute::AlwaysInline;
  case bitc::ATTR_KIND_BUILTIN:
    return Attribute::Builtin;
  case bitc::ATTR_KIND_BY_VAL:
    return Attribute::ByVal;
  case bitc::ATTR_KIND_COLD:
    return Attribute::Cold;
  case bitc::ATTR_KIND_INLINE_HINT:
    return Attribute::InlineHint;
  case bitc::ATTR_KIND_IN_REG:
    return Attribute::InReg;
  case bitc::ATTR_KIND_MIN_SIZE:
    return Attribute::MinSize;
  case bitc::ATTR_KIND_NAKED:
    return Attribute::Naked;
  case bitc::ATTR_KIND_NEST:
    return Attribute::Nest;
  case bitc::ATTR_KIND_NO_ALIAS:
    return Attribute::NoAlias;
  case bitc::ATTR_KIND_NO_BUILTIN:
    return Attribute::NoBuiltin;
  case bitc::ATTR_KIND_NO_CAPTURE:
    return Attribute::NoCapture;
  case bitc::ATTR_KIND_NO_DUPLICATE:
    return Attribute::NoDuplicate;
  case bitc::ATTR_KIND_NO_IMPLICIT_FLOAT:
    return Attribute::NoImplicitFloat;
  case bitc::ATTR_KIND_NO_INLINE:
    return Attribute::NoInline;
  case bitc::ATTR_KIND_NON_LAZY_BIND:
    return Attribute::NonLazyBind;
  case bitc::ATTR_KIND_NO_RED_ZONE:
    return Attribute::NoRedZone;
  case bitc::ATTR_KIND_NO_RETURN:
    return Attribute::NoReturn;
  case bitc::ATTR_KIND_NO_UNWIND:
    return Attribute::NoUnwind;
  case bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE:
    return Attribute::OptimizeForSize;
  case bitc::ATTR_KIND_OPTIMIZE_NONE:
    return Attribute::OptimizeNone;
  case bitc::ATTR_KIND_READ_NONE:
    return Attribute::ReadNone;
  case bitc::ATTR_KIND_READ_ONLY:
    return Attribute::ReadOnly;
  case bitc::ATTR_KIND_RETURNED:
    return Attribute::Returned;
  case bitc::ATTR_KIND_RETURNS_TWICE:
    return Attribute::ReturnsTwice;
  case bitc::ATTR_KIND_S_EXT:
    return Attribute::SExt;
  case bitc::ATTR_KIND_STACK_ALIGNMENT:
    return Attribute::StackAlignment;
  case bitc::ATTR_KIND_STACK_PROTECT:
    return Attribute::StackProtect;
  case bitc::ATTR_KIND_STACK_PROTECT_REQ:
    return Attribute::StackProtectReq;
  case bitc::ATTR_KIND_STACK_PROTECT_STRONG:
    return Attribute::StackProtectStrong;
  case bitc::ATTR_KIND_STRUCT_RET:
    return Attribute::StructRet;
  case bitc::ATTR_KIND_SANITIZE_ADDRESS:
    return Attribute::SanitizeAddress;
  case bitc::ATTR_KIND_SANITIZE_THREAD:
    return Attribute::SanitizeThread;
  case bitc::ATTR_KIND_SANITIZE_MEMORY:
    return Attribute::SanitizeMemory;
  case bitc::ATTR_KIND_UW_TABLE:
    return Attribute::UWTable;
  case bitc::ATTR_KIND_Z_EXT:
    return Attribute::ZExt;
  }
}

error_code BitcodeReader::ParseAttrKind(uint64_t Code,
                                        Attribute::AttrKind *Kind) {
  *Kind = GetAttrFromCode(Code);
  if (*Kind == Attribute::None)
    return Error(InvalidValue);
  return error_code::success();
}

error_code BitcodeReader::ParseAttributeGroupBlock() {
  if (Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
    return Error(InvalidRecord);

  if (!MAttributeGroups.empty())
    return Error(InvalidMultipleBlocks);

  SmallVector<uint64_t, 64> Record;

  // Read all the records.
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      return error_code::success();
    case BitstreamEntry::Record:
      // The interesting case.
      break;
    }

    // Read a record.
    Record.clear();
    switch (Stream.readRecord(Entry.ID, Record)) {
    default:  // Default behavior: ignore.
      break;
    case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
      if (Record.size() < 3)
        return Error(InvalidRecord);

      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
          Attribute::AttrKind Kind;
          if (error_code EC = ParseAttrKind(Record[++i], &Kind))
            return EC;

          B.addAttribute(Kind);
        } else if (Record[i] == 1) { // Align attribute
          Attribute::AttrKind Kind;
          if (error_code EC = ParseAttrKind(Record[++i], &Kind))
            return EC;
          if (Kind == 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;
    }
    }
  }
}

error_code BitcodeReader::ParseTypeTable() {
  if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
    return Error(InvalidRecord);

  return ParseTypeTableBody();
}

error_code BitcodeReader::ParseTypeTableBody() {
  if (!TypeList.empty())
    return Error(InvalidMultipleBlocks);

  SmallVector<uint64_t, 64> Record;
  unsigned NumRecords = 0;

  SmallString<64> TypeName;

  // Read all the records for this type table.
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      if (NumRecords != TypeList.size())
        return Error(MalformedBlock);
      return error_code::success();
    case BitstreamEntry::Record:
      // The interesting case.
      break;
    }

    // Read a record.
    Record.clear();
    Type *ResultTy = 0;
    switch (Stream.readRecord(Entry.ID, Record)) {
    default:
      return Error(InvalidValue);
    case bitc::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);
      TypeList.resize(Record[0]);
      continue;
    case bitc::TYPE_CODE_VOID:      // VOID
      ResultTy = Type::getVoidTy(Context);
      break;
    case bitc::TYPE_CODE_HALF:     // HALF
      ResultTy = Type::getHalfTy(Context);
      break;
    case bitc::TYPE_CODE_FLOAT:     // FLOAT
      ResultTy = Type::getFloatTy(Context);
      break;
    case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
      ResultTy = Type::getDoubleTy(Context);
      break;
    case bitc::TYPE_CODE_X86_FP80:  // X86_FP80
      ResultTy = Type::getX86_FP80Ty(Context);
      break;
    case bitc::TYPE_CODE_FP128:     // FP128
      ResultTy = Type::getFP128Ty(Context);
      break;
    case bitc::TYPE_CODE_PPC_FP128: // PPC_FP128
      ResultTy = Type::getPPC_FP128Ty(Context);
      break;
    case bitc::TYPE_CODE_LABEL:     // LABEL
      ResultTy = Type::getLabelTy(Context);
      break;
    case bitc::TYPE_CODE_METADATA:  // METADATA
      ResultTy = Type::getMetadataTy(Context);
      break;
    case bitc::TYPE_CODE_X86_MMX:   // X86_MMX
      ResultTy = Type::getX86_MMXTy(Context);
      break;
    case bitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
      if (Record.size() < 1)
        return Error(InvalidRecord);

      ResultTy = IntegerType::get(Context, Record[0]);
      break;
    case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
                                    //          [pointee type, address space]
      if (Record.size() < 1)
        return Error(InvalidRecord);
      unsigned AddressSpace = 0;
      if (Record.size() == 2)
        AddressSpace = Record[1];
      ResultTy = getTypeByID(Record[0]);
      if (ResultTy == 0)
        return Error(InvalidType);
      ResultTy = PointerType::get(ResultTy, AddressSpace);
      break;
    }
    case bitc::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(InvalidRecord);
      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(InvalidType);

      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
      break;
    }
    case bitc::TYPE_CODE_FUNCTION: {
      // FUNCTION: [vararg, retty, paramty x N]
      if (Record.size() < 2)
        return Error(InvalidRecord);
      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);

      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
      break;
    }
    case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
      if (Record.size() < 1)
        return Error(InvalidRecord);
      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(InvalidType);
      ResultTy = StructType::get(Context, EltTys, Record[0]);
      break;
    }
    case bitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
      if (ConvertToString(Record, 0, TypeName))
        return Error(InvalidRecord);
      continue;

    case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
      if (Record.size() < 1)
        return Error(InvalidRecord);

      if (NumRecords >= TypeList.size())
        return Error(InvalidTYPETable);

      // 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(InvalidRecord);
      Res->setBody(EltTys, Record[0]);
      ResultTy = Res;
      break;
    }
    case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
      if (Record.size() != 1)
        return Error(InvalidRecord);

      if (NumRecords >= TypeList.size())
        return Error(InvalidTYPETable);

      // 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 bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
      if (Record.size() < 2)
        return Error(InvalidRecord);
      if ((ResultTy = getTypeByID(Record[1])))
        ResultTy = ArrayType::get(ResultTy, Record[0]);
      else
        return Error(InvalidType);
      break;
    case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
      if (Record.size() < 2)
        return Error(InvalidRecord);
      if ((ResultTy = getTypeByID(Record[1])))
        ResultTy = VectorType::get(ResultTy, Record[0]);
      else
        return Error(InvalidType);
      break;
    }

    if (NumRecords >= TypeList.size())
      return Error(InvalidTYPETable);
    assert(ResultTy && "Didn't read a type?");
    assert(TypeList[NumRecords] == 0 && "Already read type?");
    TypeList[NumRecords++] = ResultTy;
  }
}

error_code BitcodeReader::ParseValueSymbolTable() {
  if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
    return Error(InvalidRecord);

  SmallVector<uint64_t, 64> Record;

  // Read all the records for this value table.
  SmallString<128> ValueName;
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      return error_code::success();
    case BitstreamEntry::Record:
      // The interesting case.
      break;
    }

    // Read a record.
    Record.clear();
    switch (Stream.readRecord(Entry.ID, Record)) {
    default:  // Default behavior: unknown type.
      break;
    case bitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
      if (ConvertToString(Record, 1, ValueName))
        return Error(InvalidRecord);
      unsigned ValueID = Record[0];
      if (ValueID >= ValueList.size())
        return Error(InvalidRecord);
      Value *V = ValueList[ValueID];

      V->setName(StringRef(ValueName.data(), ValueName.size()));
      ValueName.clear();
      break;
    }
    case bitc::VST_CODE_BBENTRY: {
      if (ConvertToString(Record, 1, ValueName))
        return Error(InvalidRecord);
      BasicBlock *BB = getBasicBlock(Record[0]);
      if (BB == 0)
        return Error(InvalidRecord);

      BB->setName(StringRef(ValueName.data(), ValueName.size()));
      ValueName.clear();
      break;
    }
    }
  }
}

error_code BitcodeReader::ParseMetadata() {
  unsigned NextMDValueNo = MDValueList.size();

  if (Stream.EnterSubBlock(bitc::METADATA_BLOCK_ID))
    return Error(InvalidRecord);

  SmallVector<uint64_t, 64> Record;

  // Read all the records.
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      return error_code::success();
    case BitstreamEntry::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 bitc::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 == bitc::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(InvalidRecord);
        NMD->addOperand(MD);
      }
      break;
    }
    case bitc::METADATA_FN_NODE:
      IsFunctionLocal = true;
      // fall-through
    case bitc::METADATA_NODE: {
      if (Record.size() % 2 == 1)
        return Error(InvalidRecord);

      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(InvalidRecord);
        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 bitc::METADATA_STRING: {
      SmallString<8> String(Record.begin(), Record.end());
      Value *V = MDString::get(Context, String);
      MDValueList.AssignValue(V, NextMDValueNo++);
      break;
    }
    case bitc::METADATA_KIND: {
      if (Record.size() < 2)
        return Error(InvalidRecord);

      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(ConflictingMETADATA_KINDRecords);
      break;
    }
    }
  }
}

/// decodeSignRotatedValue - Decode a signed value stored with the sign bit in
/// the LSB for dense VBR encoding.
uint64_t BitcodeReader::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.
error_code BitcodeReader::ResolveGlobalAndAliasInits() {
  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
  std::vector<std::pair<Function*, unsigned> > FunctionPrefixWorklist;

  GlobalInitWorklist.swap(GlobalInits);
  AliasInitWorklist.swap(AliasInits);
  FunctionPrefixWorklist.swap(FunctionPrefixes);

  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(ExpectedConstant);
    }
    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(ExpectedConstant);
    }
    AliasInitWorklist.pop_back();
  }

  while (!FunctionPrefixWorklist.empty()) {
    unsigned ValID = FunctionPrefixWorklist.back().second;
    if (ValID >= ValueList.size()) {
      FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
    } else {
      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
        FunctionPrefixWorklist.back().first->setPrefixData(C);
      else
        return Error(ExpectedConstant);
    }
    FunctionPrefixWorklist.pop_back();
  }

  return error_code::success();
}

static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
  SmallVector<uint64_t, 8> Words(Vals.size());
  std::transform(Vals.begin(), Vals.end(), Words.begin(),
                 BitcodeReader::decodeSignRotatedValue);

  return APInt(TypeBits, Words);
}

error_code BitcodeReader::ParseConstants() {
  if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
    return Error(InvalidRecord);

  SmallVector<uint64_t, 64> Record;

  // Read all the records for this value table.
  Type *CurTy = Type::getInt32Ty(Context);
  unsigned NextCstNo = ValueList.size();
  while (1) {
    BitstreamEntry Entry = Stream.advanceSkippingSubblocks();

    switch (Entry.Kind) {
    case BitstreamEntry::SubBlock: // Handled for us already.
    case BitstreamEntry::Error:
      return Error(MalformedBlock);
    case BitstreamEntry::EndBlock:
      if (NextCstNo != ValueList.size())
        return Error(InvalidConstantReference);

      // Once all the constants have been read, go through and resolve forward
      // references.
      ValueList.ResolveConstantForwardRefs();
      return error_code::success();
    case BitstreamEntry::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 bitc::CST_CODE_UNDEF:     // UNDEF
      V = UndefValue::get(CurTy);
      break;
    case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
      if (Record.empty())
        return Error(InvalidRecord);
      if (Record[0] >= TypeList.size())
        return Error(InvalidRecord);
      CurTy = TypeList[Record[0]];
      continue;  // Skip the ValueList manipulation.
    case bitc::CST_CODE_NULL:      // NULL
      V = Constant::getNullValue(CurTy);
      break;
    case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
      if (!CurTy->isIntegerTy() || Record.empty())
        return Error(InvalidRecord);
      V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
      break;
    case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
      if (!CurTy->isIntegerTy() || Record.empty())
        return Error(InvalidRecord);

      APInt VInt = ReadWideAPInt(Record,
                                 cast<IntegerType>(CurTy)->getBitWidth());
      V = ConstantInt::get(Context, VInt);

      break;
    }
    case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
      if (Record.empty())
        return Error(InvalidRecord);
      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 bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
      if (Record.empty())
        return Error(InvalidRecord);

      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 bitc::CST_CODE_STRING:    // STRING: [values]
    case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
      if (Record.empty())
        return Error(InvalidRecord);

      SmallString<16> Elts(Record.begin(), Record.end());
      V = ConstantDataArray::getString(Context, Elts,
                                       BitCode == bitc::CST_CODE_CSTRING);
      break;
    }
    case bitc::CST_CODE_DATA: {// DATA: [n x value]
      if (Record.empty())
        return Error(InvalidRecord);

      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(InvalidTypeForValue);
      }
      break;
    }

    case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
      if (Record.size() < 3)
        return Error(InvalidRecord);
      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 << bitc::OBO_NO_SIGNED_WRAP))
              Flags |= OverflowingBinaryOperator::NoSignedWrap;
            if (Record[3] & (1 << bitc::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 << bitc::PEO_EXACT))
              Flags |= SDivOperator::IsExact;
          }
        }
        V = ConstantExpr::get(Opc, LHS, RHS, Flags);
      }
      break;
    }
    case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
      if (Record.size() < 3)
        return Error(InvalidRecord);
      int Opc = GetDecodedCastOpcode(Record[0]);
      if (Opc < 0) {
        V = UndefValue::get(CurTy);  // Unknown cast.
      } else {
        Type *OpTy = getTypeByID(Record[1]);
        if (!OpTy)
          return Error(InvalidRecord);
        Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
        V = UpgradeBitCastExpr(Opc, Op, CurTy);
        if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
      }
      break;
    }
    case bitc::CST_CODE_CE_INBOUNDS_GEP:
    case bitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
      if (Record.size() & 1)
        return Error(InvalidRecord);
      SmallVector<Constant*, 16> Elts;
      for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
        Type *ElTy = getTypeByID(Record[i]);
        if (!ElTy)
          return Error(InvalidRecord);
        Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
      }
      ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
      V = ConstantExpr::getGetElementPtr(Elts[0], Indices,
                                         BitCode ==
                                           bitc::CST_CODE_CE_INBOUNDS_GEP);
      break;
    }
    case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
      if (Record.size() < 3)
        return Error(InvalidRecord);

      Type *SelectorTy = Type::getInt1Ty(Context);

      // If CurTy is a vector of length n, then Record[0] must be a <n x i1>
      // vector. Otherwise, it must be a single bit.
      if (VectorType *VTy = dyn_cast<VectorType>(CurTy))
        SelectorTy = VectorType::get(Type::getInt1Ty(Context),
                                     VTy->getNumElements());

      V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
                                                              SelectorTy),
                                  ValueList.getConstantFwdRef(Record[1],CurTy),
                                  ValueList.getConstantFwdRef(Record[2],CurTy));
      break;
    }
    case bitc::CST_CODE_CE_EXTRACTELT: { // CE_EXTRACTELT: [opty, opval, opval]
      if (Record.size() < 3)
        return Error(InvalidRecord);
      VectorType *OpTy =
        dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
      if (OpTy == 0)
        return Error(InvalidRecord);
      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
      Constant *Op1 = ValueList.getConstantFwdRef(Record[2],
                                                  Type::getInt32Ty(Context));
      V = ConstantExpr::getExtractElement(Op0, Op1);
      break;
    }
    case bitc::CST_CODE_CE_INSERTELT: { // CE_INSERTELT: [opval, opval, opval]
      VectorType *OpTy = dyn_cast<VectorType>(CurTy);
      if (Record.size() < 3 || OpTy == 0)
        return Error(InvalidRecord);
      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 bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
      VectorType *OpTy = dyn_cast<VectorType>(CurTy);
      if (Record.size() < 3 || OpTy == 0)
        return Error(InvalidRecord);
      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 bitc::CST_CODE_CE_SHUFVEC_EX: { // [opty, opval, op…