Ejemplo n.º 1
0
APSIntType::RangeTestResultKind
APSIntType::testInRange(const llvm::APSInt &Value,
                        bool AllowSignConversions) const {

  // Negative numbers cannot be losslessly converted to unsigned type.
  if (IsUnsigned && !AllowSignConversions &&
      Value.isSigned() && Value.isNegative())
    return RTR_Below;

  unsigned MinBits;
  if (AllowSignConversions) {
    if (Value.isSigned() && !IsUnsigned)
      MinBits = Value.getMinSignedBits();
    else
      MinBits = Value.getActiveBits();

  } else {
    // Signed integers can be converted to signed integers of the same width
    // or (if positive) unsigned integers with one fewer bit.
    // Unsigned integers can be converted to unsigned integers of the same width
    // or signed integers with one more bit.
    if (Value.isSigned())
      MinBits = Value.getMinSignedBits() - IsUnsigned;
    else
      MinBits = Value.getActiveBits() + !IsUnsigned;
  }

  if (MinBits <= BitWidth)
    return RTR_Within;

  if (Value.isSigned() && Value.isNegative())
    return RTR_Below;
  else
    return RTR_Above;
}
Ejemplo n.º 2
0
/// \brief Determine if two APSInts have the same value, zero- or sign-extending
/// as needed.
static bool IsSameValue(const llvm::APSInt &I1, const llvm::APSInt &I2) {
  if (I1.getBitWidth() == I2.getBitWidth() && I1.isSigned() == I2.isSigned())
    return I1 == I2;
  
  // Check for a bit-width mismatch.
  if (I1.getBitWidth() > I2.getBitWidth())
    return IsSameValue(I1, I2.extend(I1.getBitWidth()));
  else if (I2.getBitWidth() > I1.getBitWidth())
    return IsSameValue(I1.extend(I2.getBitWidth()), I2);
  
  // We have a signedness mismatch. Turn the signed value into an unsigned 
  // value.
  if (I1.isSigned()) {
    if (I1.isNegative())
      return false;
    
    return llvm::APSInt(I1, true) == I2;
  }
 
  if (I2.isNegative())
    return false;
  
  return I1 == llvm::APSInt(I2, true);
}
Ejemplo n.º 3
0
bool LiteralAnalyser::checkRange(QualType TLeft, const Expr* Right, clang::SourceLocation Loc, llvm::APSInt Result) {
    // TODO refactor with check()
    const QualType QT = TLeft.getCanonicalType();
    int availableWidth = 0;
    if (QT.isBuiltinType()) {
        const BuiltinType* TL = cast<BuiltinType>(QT);
        if (!TL->isInteger()) {
            // TODO floats
            return false;
        }
        availableWidth = TL->getIntegerWidth();
    } else {
        QT.dump();
        assert(0 && "todo");
    }

    const Limit* L = getLimit(availableWidth);
    assert(Result.isSigned() && "TEMP FOR NOW");
    int64_t value = Result.getSExtValue();
    bool overflow = false;
    if (Result.isNegative()) {
        const int64_t limit = L->minVal;
        if (value < limit) overflow = true;
    } else {
        const int64_t limit = (int64_t)L->maxVal;
        if (value > limit) overflow = true;
    }
    //fprintf(stderr, "VAL=%lld  width=%d signed=%d\n", value, availableWidth, Result.isSigned());
    if (overflow) {
        SmallString<20> ss;
        Result.toString(ss, 10, true);

        StringBuilder buf1;
        TLeft->DiagName(buf1);

        if (Right) {
            Diags.Report(Right->getLocStart(), diag::err_literal_outofbounds)
                    << buf1 << L->minStr << L->maxStr << ss << Right->getSourceRange();
        } else {
            Diags.Report(Loc, diag::err_literal_outofbounds)
                    << buf1 << L->minStr << L->maxStr << ss;
        }
        return false;
    }
    return true;
}
Ejemplo n.º 4
0
SVal SimpleSValBuilder::MakeSymIntVal(const SymExpr *LHS,
                                    BinaryOperator::Opcode op,
                                    const llvm::APSInt &RHS,
                                    QualType resultTy) {
  bool isIdempotent = false;

  // Check for a few special cases with known reductions first.
  switch (op) {
  default:
    // We can't reduce this case; just treat it normally.
    break;
  case BO_Mul:
    // a*0 and a*1
    if (RHS == 0)
      return makeIntVal(0, resultTy);
    else if (RHS == 1)
      isIdempotent = true;
    break;
  case BO_Div:
    // a/0 and a/1
    if (RHS == 0)
      // This is also handled elsewhere.
      return UndefinedVal();
    else if (RHS == 1)
      isIdempotent = true;
    break;
  case BO_Rem:
    // a%0 and a%1
    if (RHS == 0)
      // This is also handled elsewhere.
      return UndefinedVal();
    else if (RHS == 1)
      return makeIntVal(0, resultTy);
    break;
  case BO_Add:
  case BO_Sub:
  case BO_Shl:
  case BO_Shr:
  case BO_Xor:
    // a+0, a-0, a<<0, a>>0, a^0
    if (RHS == 0)
      isIdempotent = true;
    break;
  case BO_And:
    // a&0 and a&(~0)
    if (RHS == 0)
      return makeIntVal(0, resultTy);
    else if (RHS.isAllOnesValue())
      isIdempotent = true;
    break;
  case BO_Or:
    // a|0 and a|(~0)
    if (RHS == 0)
      isIdempotent = true;
    else if (RHS.isAllOnesValue()) {
      const llvm::APSInt &Result = BasicVals.Convert(resultTy, RHS);
      return nonloc::ConcreteInt(Result);
    }
    break;
  }

  // Idempotent ops (like a*1) can still change the type of an expression.
  // Wrap the LHS up in a NonLoc again and let evalCastFromNonLoc do the
  // dirty work.
  if (isIdempotent)
      return evalCastFromNonLoc(nonloc::SymbolVal(LHS), resultTy);

  // If we reach this point, the expression cannot be simplified.
  // Make a SymbolVal for the entire expression, after converting the RHS.
  const llvm::APSInt *ConvertedRHS = &RHS;
  if (BinaryOperator::isComparisonOp(op)) {
    // We're looking for a type big enough to compare the symbolic value
    // with the given constant.
    // FIXME: This is an approximation of Sema::UsualArithmeticConversions.
    ASTContext &Ctx = getContext();
    QualType SymbolType = LHS->getType();
    uint64_t ValWidth = RHS.getBitWidth();
    uint64_t TypeWidth = Ctx.getTypeSize(SymbolType);

    if (ValWidth < TypeWidth) {
      // If the value is too small, extend it.
      ConvertedRHS = &BasicVals.Convert(SymbolType, RHS);
    } else if (ValWidth == TypeWidth) {
      // If the value is signed but the symbol is unsigned, do the comparison
      // in unsigned space. [C99 6.3.1.8]
      // (For the opposite case, the value is already unsigned.)
      if (RHS.isSigned() && !SymbolType->isSignedIntegerOrEnumerationType())
        ConvertedRHS = &BasicVals.Convert(SymbolType, RHS);
    }
  } else
    ConvertedRHS = &BasicVals.Convert(resultTy, RHS);

  return makeNonLoc(LHS, op, *ConvertedRHS, resultTy);
}