path: root/lib/Bitcode/Reader/BitcodeReader.cpp

//===- BitcodeReader.cpp - Internal BitcodeReader implementation ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License.  See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header defines the BitcodeReader class.
//
//===----------------------------------------------------------------------===//

#include "BitcodeReader.h"
#include "llvm/Bitcode/BitstreamReader.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;

/// ConvertToString - Convert a string from a record into an std::string, return
/// true on failure.
template<typename StrTy>
static bool ConvertToString(SmallVector<uint64_t, 64> &Record, unsigned Idx,
                            StrTy &Result) {
  if (Record.size() < Idx+1 || Record.size() < Record[Idx]+Idx+1)
    return true;
  
  for (unsigned i = 0, e = Record[Idx]; i != e; ++i)
    Result += (char)Record[Idx+i+1];
  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::WeakLinkage;
  case 2: return GlobalValue::AppendingLinkage;
  case 3: return GlobalValue::InternalLinkage;
  case 4: return GlobalValue::LinkOnceLinkage;
  case 5: return GlobalValue::DLLImportLinkage;
  case 6: return GlobalValue::DLLExportLinkage;
  case 7: return GlobalValue::ExternalWeakLinkage;
  }
}

static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
  switch (Val) {
  default: // Map unknown visibilities to default.
  case 0: return GlobalValue::DefaultVisibility;
  case 1: return GlobalValue::HiddenVisibility;
  }
}

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;
  }
}
static int GetDecodedBinaryOpcode(unsigned Val, const Type *Ty) {
  switch (Val) {
  default: return -1;
  case bitc::BINOP_ADD:  return Instruction::Add;
  case bitc::BINOP_SUB:  return Instruction::Sub;
  case bitc::BINOP_MUL:  return Instruction::Mul;
  case bitc::BINOP_UDIV: return Instruction::UDiv;
  case bitc::BINOP_SDIV:
    return Ty->isFPOrFPVector() ? Instruction::FDiv : Instruction::SDiv;
  case bitc::BINOP_UREM: return Instruction::URem;
  case bitc::BINOP_SREM:
    return Ty->isFPOrFPVector() ? 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;
  }
}


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 {
    ConstantPlaceHolder();                       // DO NOT IMPLEMENT
    void operator=(const ConstantPlaceHolder &); // DO NOT IMPLEMENT
  public:
    Use Op;
    ConstantPlaceHolder(const Type *Ty)
      : ConstantExpr(Ty, Instruction::UserOp1, &Op, 1),
        Op(UndefValue::get(Type::Int32Ty), this) {
    }
  };
}

Constant *BitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
                                                    const Type *Ty) {
  if (Idx >= size()) {
    // Insert a bunch of null values.
    Uses.resize(Idx+1);
    OperandList = &Uses[0];