C++ llvm::APSInt类代码示例

ProgramStateRef SimpleConstraintManager::assumeInclusiveRange(
    ProgramStateRef State, NonLoc Value, const llvm::APSInt &From,
    const llvm::APSInt &To, bool InRange) {

  assert(From.isUnsigned() == To.isUnsigned() &&
         From.getBitWidth() == To.getBitWidth() &&
         "Values should have same types!");

  if (!canReasonAbout(Value)) {
    // Just add the constraint to the expression without trying to simplify.
    SymbolRef Sym = Value.getAsSymExpr();
    assert(Sym);
    return assumeSymWithinInclusiveRange(State, Sym, From, To, InRange);
  }

  switch (Value.getSubKind()) {
  default:
    llvm_unreachable("'assumeInclusiveRange' is not implemented"
                     "for this NonLoc");

  case nonloc::LocAsIntegerKind:
  case nonloc::SymbolValKind: {
    if (SymbolRef Sym = Value.getAsSymbol())
      return assumeSymWithinInclusiveRange(State, Sym, From, To, InRange);
    return State;
  } // end switch

  case nonloc::ConcreteIntKind: {
    const llvm::APSInt &IntVal = Value.castAs<nonloc::ConcreteInt>().getValue();
    bool IsInRange = IntVal >= From && IntVal <= To;
    bool isFeasible = (IsInRange == InRange);
    return isFeasible ? State : nullptr;
  }
  } // end switch
}

DWARFExpression lldb_private::npdb::MakeConstantLocationExpression(
    TypeIndex underlying_ti, TpiStream &tpi, const llvm::APSInt &constant,
    ModuleSP module) {
  const ArchSpec &architecture = module->GetArchitecture();
  uint32_t address_size = architecture.GetAddressByteSize();

  size_t size = 0;
  bool is_signed = false;
  std::tie(size, is_signed) = GetIntegralTypeInfo(underlying_ti, tpi);

  union {
    llvm::support::little64_t I;
    llvm::support::ulittle64_t U;
  } Value;

  std::shared_ptr<DataBufferHeap> buffer = std::make_shared<DataBufferHeap>();
  buffer->SetByteSize(size);

  llvm::ArrayRef<uint8_t> bytes;
  if (is_signed) {
    Value.I = constant.getSExtValue();
  } else {
    Value.U = constant.getZExtValue();
  }

  bytes = llvm::makeArrayRef(reinterpret_cast<const uint8_t *>(&Value), 8)
              .take_front(size);
  buffer->CopyData(bytes.data(), size);
  DataExtractor extractor(buffer, lldb::eByteOrderLittle, address_size);
  DWARFExpression result(nullptr, extractor, nullptr, 0, size);
  return result;
}

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;
}

ProgramStateRef 
BasicConstraintManager::assumeSymLE(ProgramStateRef state,
                                    SymbolRef sym,
                                    const llvm::APSInt &V,
                                    const llvm::APSInt &Adjustment) {
  // Reject a path if the value of sym is a constant X and !(X+Adj <= V).
  if (const llvm::APSInt* X = getSymVal(state, sym)) {
    bool isFeasible = (*X <= V-Adjustment);
    return isFeasible ? state : NULL;
  }

  // Sym is not a constant, but it is worth looking to see if V is the
  // minimum integer value.
  if (V == llvm::APSInt::getMinValue(V.getBitWidth(), V.isUnsigned())) {
    llvm::APSInt Adjusted = V-Adjustment;

    // If we know that sym != V (after adjustment), then this condition
    // is infeasible since there is no other value less than V.
    bool isFeasible = !isNotEqual(state, sym, Adjusted);

    // If the path is still feasible then as a consequence we know that
    // 'sym+Adjustment == V' because there are no smaller values.
    // Add this constraint.
    return isFeasible ? AddEQ(state, sym, Adjusted) : NULL;
  }

  return state;
}

ProgramStateRef 
BasicConstraintManager::assumeSymGT(ProgramStateRef state,
                                    SymbolRef sym,
                                    const llvm::APSInt &V,
                                    const llvm::APSInt &Adjustment) {
  // Is 'V' the largest possible value?
  if (V == llvm::APSInt::getMaxValue(V.getBitWidth(), V.isUnsigned())) {
    // sym cannot be any value greater than 'V'.  This path is infeasible.
    return NULL;
  }

  // FIXME: For now have assuming x > y be the same as assuming sym != V;
  return assumeSymNE(state, sym, V, Adjustment);
}

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;
}

TemplateArgument::TemplateArgument(ASTContext &Ctx, const llvm::APSInt &Value,
                                   QualType Type) {
  Integer.Kind = Integral;
  // Copy the APSInt value into our decomposed form.
  Integer.BitWidth = Value.getBitWidth();
  Integer.IsUnsigned = Value.isUnsigned();
  // If the value is large, we have to get additional memory from the ASTContext
  unsigned NumWords = Value.getNumWords();
  if (NumWords > 1) {
    void *Mem = Ctx.Allocate(NumWords * sizeof(uint64_t));
    std::memcpy(Mem, Value.getRawData(), NumWords * sizeof(uint64_t));
    Integer.pVal = static_cast<uint64_t *>(Mem);
  } else {
    Integer.VAL = Value.getZExtValue();
  }

  Integer.Type = Type.getAsOpaquePtr();
}

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);
}

/// \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);
}

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) {
    if (SymbolRef LHSSym = dyn_cast<SymbolData>(LHS))
      return evalCastFromNonLoc(nonloc::SymbolVal(LHSSym), resultTy);
    return evalCastFromNonLoc(nonloc::SymExprVal(LHS), resultTy);
  }

  // If we reach this point, the expression cannot be simplified.
  // Make a SymExprVal for the entire thing.
  return makeNonLoc(LHS, op, RHS, resultTy);
}

 bool isUnsigned() const { return Val.isUnsigned(); }

 unsigned getBitWidth() const { return Val.getBitWidth(); }