C++ BasicValueFactory类代码示例

// Turn all [A, B] ranges to [-B, -A]. Ranges [MIN, B] are turned to range set
// [MIN, MIN] U [-B, MAX], when MIN and MAX are the minimal and the maximal
// signed values of the type.
RangeSet RangeSet::Negate(BasicValueFactory &BV, Factory &F) const {
  PrimRangeSet newRanges = F.getEmptySet();

  for (iterator i = begin(), e = end(); i != e; ++i) {
    const llvm::APSInt &from = i->From(), &to = i->To();
    const llvm::APSInt &newTo = (from.isMinSignedValue() ?
                                 BV.getMaxValue(from) :
                                 BV.getValue(- from));
    if (to.isMaxSignedValue() && !newRanges.isEmpty() &&
        newRanges.begin()->From().isMinSignedValue()) {
      assert(newRanges.begin()->To().isMinSignedValue() &&
             "Ranges should not overlap");
      assert(!from.isMinSignedValue() && "Ranges should not overlap");
      const llvm::APSInt &newFrom = newRanges.begin()->From();
      newRanges =
        F.add(F.remove(newRanges, *newRanges.begin()), Range(newFrom, newTo));
    } else if (!to.isMinSignedValue()) {
      const llvm::APSInt &newFrom = BV.getValue(- to);
      newRanges = F.add(newRanges, Range(newFrom, newTo));
    }
    if (from.isMinSignedValue()) {
      newRanges = F.add(newRanges, Range(BV.getMinValue(from),
                                         BV.getMinValue(from)));
    }
  }

  return newRanges;
}

/// Apply implicit constraints for bitwise OR- and AND-.
/// For unsigned types, bitwise OR with a constant always returns
/// a value greater-or-equal than the constant, and bitwise AND
/// returns a value less-or-equal then the constant.
///
/// Pattern matches the expression \p Sym against those rule,
/// and applies the required constraints.
/// \p Input Previously established expression range set
static RangeSet applyBitwiseConstraints(
    BasicValueFactory &BV,
    RangeSet::Factory &F,
    RangeSet Input,
    const SymIntExpr* SIE) {
  QualType T = SIE->getType();
  bool IsUnsigned = T->isUnsignedIntegerType();
  const llvm::APSInt &RHS = SIE->getRHS();
  const llvm::APSInt &Zero = BV.getAPSIntType(T).getZeroValue();
  BinaryOperator::Opcode Operator = SIE->getOpcode();

  // For unsigned types, the output of bitwise-or is bigger-or-equal than RHS.
  if (Operator == BO_Or && IsUnsigned)
    return Input.Intersect(BV, F, RHS, BV.getMaxValue(T));

  // Bitwise-or with a non-zero constant is always non-zero.
  if (Operator == BO_Or && RHS != Zero)
    return assumeNonZero(BV, F, SIE, Input);

  // For unsigned types, or positive RHS,
  // bitwise-and output is always smaller-or-equal than RHS (assuming two's
  // complement representation of signed types).
  if (Operator == BO_And && (IsUnsigned || RHS >= Zero))
    return Input.Intersect(BV, F, BV.getMinValue(T), RHS);

  return Input;
}

/// Return a range set subtracting zero from \p Domain.
static RangeSet assumeNonZero(
    BasicValueFactory &BV,
    RangeSet::Factory &F,
    SymbolRef Sym,
    RangeSet Domain) {
  APSIntType IntType = BV.getAPSIntType(Sym->getType());
  return Domain.Intersect(BV, F, ++IntType.getZeroValue(),
      --IntType.getZeroValue());
}

// Returns a set containing the values in the receiving set, intersected with
// the closed range [Lower, Upper]. Unlike the Range type, this range uses
// modular arithmetic, corresponding to the common treatment of C integer
// overflow. Thus, if the Lower bound is greater than the Upper bound, the
// range is taken to wrap around. This is equivalent to taking the
// intersection with the two ranges [Min, Upper] and [Lower, Max],
// or, alternatively, /removing/ all integers between Upper and Lower.
RangeSet RangeSet::Intersect(BasicValueFactory &BV, Factory &F,
                             llvm::APSInt Lower, llvm::APSInt Upper) const {
  if (!pin(Lower, Upper))
    return F.getEmptySet();

  PrimRangeSet newRanges = F.getEmptySet();

  PrimRangeSet::iterator i = begin(), e = end();
  if (Lower <= Upper)
    IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
  else {
    // The order of the next two statements is important!
    // IntersectInRange() does not reset the iteration state for i and e.
    // Therefore, the lower range most be handled first.
    IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
    IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
  }

  return newRanges;
}

SVal nonloc::ConcreteInt::EvalBinOp(BasicValueFactory& BasicVals,
                                     BinaryOperator::Opcode Op,
                                     const nonloc::ConcreteInt& R) const {
  
  const llvm::APSInt* X =
    BasicVals.EvaluateAPSInt(Op, getValue(), R.getValue());
  
  if (X)
    return nonloc::ConcreteInt(*X);
  else
    return UndefinedVal();
}

 /// AddNE - Create a new RangeSet with the additional constraint that the
 ///  value be not be equal to V.
 RangeSet AddNE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
   PrimRangeSet newRanges = ranges;
   
   // FIXME: We can perhaps enhance ImmutableSet to do this search for us
   // in log(N) time using the sorted property of the internal AVL tree.
   for (iterator i = begin(), e = end(); i != e; ++i) {
     if (i->Includes(V)) {
       // Remove the old range.
       newRanges = F.Remove(newRanges, *i);
       // Split the old range into possibly one or two ranges.
       if (V != i->From())
         newRanges = F.Add(newRanges, Range(i->From(), BV.Sub1(V)));
       if (V != i->To())
         newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
       // All of the ranges are non-overlapping, so we can stop.        
       break;
     }
   }
   
   return newRanges;
 }

  RangeSet AddGT(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
    PrimRangeSet newRanges = F.GetEmptySet();

    for (PrimRangeSet::iterator i = begin(), e = end(); i != e; ++i) {
      if (i->Includes(V) && i->To() > V)
        newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
      else if (i->From() > V)
        newRanges = F.Add(newRanges, *i);
    }
    
    return newRanges;
  }

SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals,
                                 BinaryOperator::Opcode Op,
                                 const loc::ConcreteInt& R) const {

  assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub);

  const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());

  if (X)
    return nonloc::ConcreteInt(*X);
  else
    return UndefinedVal();
}

SVal loc::ConcreteInt::EvalBinOp(BasicValueFactory& BasicVals,
                                 BinaryOperator::Opcode Op,
                                 const loc::ConcreteInt& R) const {

  assert (Op == BinaryOperator::Add || Op == BinaryOperator::Sub ||
          (Op >= BinaryOperator::LT && Op <= BinaryOperator::NE));

  const llvm::APSInt* X = BasicVals.EvaluateAPSInt(Op, getValue(), R.getValue());

  if (X)
    return loc::ConcreteInt(*X);
  else
    return UndefinedVal();
}

void RangeSet::IntersectInRange(BasicValueFactory &BV, Factory &F,
                      const llvm::APSInt &Lower, const llvm::APSInt &Upper,
                      PrimRangeSet &newRanges, PrimRangeSet::iterator &i,
                      PrimRangeSet::iterator &e) const {
  // There are six cases for each range R in the set:
  //   1. R is entirely before the intersection range.
  //   2. R is entirely after the intersection range.
  //   3. R contains the entire intersection range.
  //   4. R starts before the intersection range and ends in the middle.
  //   5. R starts in the middle of the intersection range and ends after it.
  //   6. R is entirely contained in the intersection range.
  // These correspond to each of the conditions below.
  for (/* i = begin(), e = end() */; i != e; ++i) {
    if (i->To() < Lower) {
      continue;
    }
    if (i->From() > Upper) {
      break;
    }

    if (i->Includes(Lower)) {
      if (i->Includes(Upper)) {
        newRanges =
            F.add(newRanges, Range(BV.getValue(Lower), BV.getValue(Upper)));
        break;
      } else
        newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
    } else {
      if (i->Includes(Upper)) {
        newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
        break;
      } else
        newRanges = F.add(newRanges, *i);
    }
  }
}

NonLoc NonLoc::MakeIntTruthVal(BasicValueFactory& BasicVals, bool b) {
  return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
}

nonloc::ConcreteInt
nonloc::ConcreteInt::EvalComplement(BasicValueFactory& BasicVals) const {
  return BasicVals.getValue(~getValue()); 
}

nonloc::ConcreteInt
nonloc::ConcreteInt::EvalMinus(BasicValueFactory& BasicVals, UnaryOperator* U) const {
  assert (U->getType() == U->getSubExpr()->getType());  
  assert (U->getType()->isIntegerType());  
  return BasicVals.getValue(-getValue()); 
}

NonLoc NonLoc::MakeIntVal(BasicValueFactory& BasicVals, uint64_t X, 
                          bool isUnsigned) {
  return nonloc::ConcreteInt(BasicVals.getIntValue(X, isUnsigned));
}

Loc Loc::MakeNull(BasicValueFactory &BasicVals) {
  return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
}