ProgramStateRef SimpleConstraintManager::assumeSymWithinInclusiveRange(
    ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
    const llvm::APSInt &To, bool InRange) {
  // Get the type used for calculating wraparound.
  BasicValueFactory &BVF = getBasicVals();
  APSIntType WraparoundType = BVF.getAPSIntType(Sym->getType());

  llvm::APSInt Adjustment = WraparoundType.getZeroValue();
  SymbolRef AdjustedSym = Sym;
  computeAdjustment(AdjustedSym, Adjustment);

  // Convert the right-hand side integer as necessary.
  APSIntType ComparisonType = std::max(WraparoundType, APSIntType(From));
  llvm::APSInt ConvertedFrom = ComparisonType.convert(From);
  llvm::APSInt ConvertedTo = ComparisonType.convert(To);

  // Prefer unsigned comparisons.
  if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
      ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
    Adjustment.setIsSigned(false);

  if (InRange)
    return assumeSymbolWithinInclusiveRange(State, AdjustedSym, ConvertedFrom,
                                            ConvertedTo, Adjustment);
  return assumeSymbolOutOfInclusiveRange(State, AdjustedSym, ConvertedFrom,
                                         ConvertedTo, Adjustment);
}
Esempio n. 2
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ProgramStateRef SimpleConstraintManager::assumeSymRel(ProgramStateRef State,
                                                      const SymExpr *LHS,
                                                      BinaryOperator::Opcode Op,
                                                      const llvm::APSInt &Int) {
  assert(BinaryOperator::isComparisonOp(Op) &&
         "Non-comparison ops should be rewritten as comparisons to zero.");

  // Get the type used for calculating wraparound.
  BasicValueFactory &BVF = getBasicVals();
  APSIntType WraparoundType = BVF.getAPSIntType(LHS->getType());

  // We only handle simple comparisons of the form "$sym == constant"
  // or "($sym+constant1) == constant2".
  // The adjustment is "constant1" in the above expression. It's used to
  // "slide" the solution range around for modular arithmetic. For example,
  // x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
  // in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
  // the subclasses of SimpleConstraintManager to handle the adjustment.
  SymbolRef Sym = LHS;
  llvm::APSInt Adjustment = WraparoundType.getZeroValue();
  computeAdjustment(Sym, Adjustment);

  // Convert the right-hand side integer as necessary.
  APSIntType ComparisonType = std::max(WraparoundType, APSIntType(Int));
  llvm::APSInt ConvertedInt = ComparisonType.convert(Int);

  // Prefer unsigned comparisons.
  if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
      ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
    Adjustment.setIsSigned(false);

  switch (Op) {
  default:
    llvm_unreachable("invalid operation not caught by assertion above");

  case BO_EQ:
    return assumeSymEQ(State, Sym, ConvertedInt, Adjustment);

  case BO_NE:
    return assumeSymNE(State, Sym, ConvertedInt, Adjustment);

  case BO_GT:
    return assumeSymGT(State, Sym, ConvertedInt, Adjustment);

  case BO_GE:
    return assumeSymGE(State, Sym, ConvertedInt, Adjustment);

  case BO_LT:
    return assumeSymLT(State, Sym, ConvertedInt, Adjustment);

  case BO_LE:
    return assumeSymLE(State, Sym, ConvertedInt, Adjustment);
  } // end switch
}