C++ QualType::isVariableArrayType方法代码示例

void MicrosoftCXXNameMangler::mangleExtraDimensions(QualType ElementTy) {
  llvm::SmallVector<llvm::APInt, 3> Dimensions;
  for (;;) {
    if (ElementTy->isConstantArrayType()) {
      const ConstantArrayType *CAT =
      static_cast<const ConstantArrayType *>(ElementTy.getTypePtr());
      Dimensions.push_back(CAT->getSize());
      ElementTy = CAT->getElementType();
    } else if (ElementTy->isVariableArrayType()) {
      assert(false && "Don't know how to mangle VLAs!");
    } else if (ElementTy->isDependentSizedArrayType()) {
      // The dependent expression has to be folded into a constant (TODO).
      assert(false && "Don't know how to mangle dependent-sized arrays!");
    } else if (ElementTy->isIncompleteArrayType()) continue;
    else break;
  }
  mangleQualifiers(ElementTy.getQualifiers(), false);
  // If there are any additional dimensions, mangle them now.
  if (Dimensions.size() > 0) {
    Out << 'Y';
    // <dimension-count> ::= <number> # number of extra dimensions
    mangleNumber(Dimensions.size());
    for (unsigned Dim = 0; Dim < Dimensions.size(); ++Dim) {
      mangleNumber(Dimensions[Dim].getLimitedValue());
    }
  }
  mangleType(ElementTy.getLocalUnqualifiedType());
}

void ExprEngine::
VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
                              ExplodedNode *Pred,
                              ExplodedNodeSet &Dst) {
  StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);

  QualType T = Ex->getTypeOfArgument();
  
  if (Ex->getKind() == UETT_SizeOf) {
    if (!T->isIncompleteType() && !T->isConstantSizeType()) {
      assert(T->isVariableArrayType() && "Unknown non-constant-sized type.");
      
      // FIXME: Add support for VLA type arguments and VLA expressions.
      // When that happens, we should probably refactor VLASizeChecker's code.
      return;
    }
    else if (T->getAs<ObjCObjectType>()) {
      // Some code tries to take the sizeof an ObjCObjectType, relying that
      // the compiler has laid out its representation.  Just report Unknown
      // for these.
      return;
    }
  }
  
  APSInt Value = Ex->EvaluateKnownConstInt(getContext());
  CharUnits amt = CharUnits::fromQuantity(Value.getZExtValue());
  
  ProgramStateRef state = Pred->getState();
  state = state->BindExpr(Ex, Pred->getLocationContext(),
                          svalBuilder.makeIntVal(amt.getQuantity(),
                                                     Ex->getType()));
  Bldr.generateNode(Ex, Pred, state);
}

void ExprEngine::
VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
                              ExplodedNode *Pred,
                              ExplodedNodeSet &Dst) {
  // FIXME: Prechecks eventually go in ::Visit().
  ExplodedNodeSet CheckedSet;
  getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, Ex, *this);

  ExplodedNodeSet EvalSet;
  StmtNodeBuilder Bldr(CheckedSet, EvalSet, *currBldrCtx);

  QualType T = Ex->getTypeOfArgument();

  for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
       I != E; ++I) {
    if (Ex->getKind() == UETT_SizeOf) {
      if (!T->isIncompleteType() && !T->isConstantSizeType()) {
        assert(T->isVariableArrayType() && "Unknown non-constant-sized type.");

        // FIXME: Add support for VLA type arguments and VLA expressions.
        // When that happens, we should probably refactor VLASizeChecker's code.
        continue;
      } else if (T->getAs<ObjCObjectType>()) {
        // Some code tries to take the sizeof an ObjCObjectType, relying that
        // the compiler has laid out its representation.  Just report Unknown
        // for these.
        continue;
      }
    }

    APSInt Value = Ex->EvaluateKnownConstInt(getContext());
    CharUnits amt = CharUnits::fromQuantity(Value.getZExtValue());

    ProgramStateRef state = (*I)->getState();
    state = state->BindExpr(Ex, (*I)->getLocationContext(),
                            svalBuilder.makeIntVal(amt.getQuantity(),
                                                   Ex->getType()));
    Bldr.generateNode(Ex, *I, state);
  }

  getCheckerManager().runCheckersForPostStmt(Dst, EvalSet, Ex, *this);
}

llvm::Value *CodeGenFunction::EmitVLASize(QualType Ty) {
  assert(Ty->isVariablyModifiedType() &&
         "Must pass variably modified type to EmitVLASizes!");

  EnsureInsertPoint();

  if (const VariableArrayType *VAT = getContext().getAsVariableArrayType(Ty)) {
    llvm::Value *&SizeEntry = VLASizeMap[VAT->getSizeExpr()];

    if (!SizeEntry) {
      const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());

      // Get the element size;
      QualType ElemTy = VAT->getElementType();
      llvm::Value *ElemSize;
      if (ElemTy->isVariableArrayType())
        ElemSize = EmitVLASize(ElemTy);
      else
        ElemSize = llvm::ConstantInt::get(SizeTy,
            getContext().getTypeSizeInChars(ElemTy).getQuantity());

      llvm::Value *NumElements = EmitScalarExpr(VAT->getSizeExpr());
      NumElements = Builder.CreateIntCast(NumElements, SizeTy, false, "tmp");

      SizeEntry = Builder.CreateMul(ElemSize, NumElements);
    }

    return SizeEntry;
  }

  if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
    EmitVLASize(AT->getElementType());
    return 0;
  }

  const PointerType *PT = Ty->getAs<PointerType>();
  assert(PT && "unknown VM type!");
  EmitVLASize(PT->getPointeeType());
  return 0;
}

// FIXME: should rewrite according to the cast kind.
SVal SValBuilder::evalCast(SVal val, QualType castTy, QualType originalTy) {
  castTy = Context.getCanonicalType(castTy);
  originalTy = Context.getCanonicalType(originalTy);
  if (val.isUnknownOrUndef() || castTy == originalTy)
    return val;

  if (castTy->isBooleanType()) {
    if (val.isUnknownOrUndef())
      return val;
    if (val.isConstant())
      return makeTruthVal(!val.isZeroConstant(), castTy);
    if (!Loc::isLocType(originalTy) &&
        !originalTy->isIntegralOrEnumerationType() &&
        !originalTy->isMemberPointerType())
      return UnknownVal();
    if (SymbolRef Sym = val.getAsSymbol(true)) {
      BasicValueFactory &BVF = getBasicValueFactory();
      // FIXME: If we had a state here, we could see if the symbol is known to
      // be zero, but we don't.
      return makeNonLoc(Sym, BO_NE, BVF.getValue(0, Sym->getType()), castTy);
    }
    // Loc values are not always true, they could be weakly linked functions.
    if (Optional<Loc> L = val.getAs<Loc>())
      return evalCastFromLoc(*L, castTy);

    Loc L = val.castAs<nonloc::LocAsInteger>().getLoc();
    return evalCastFromLoc(L, castTy);
  }

  // For const casts, casts to void, just propagate the value.
  if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
    if (shouldBeModeledWithNoOp(Context, Context.getPointerType(castTy),
                                         Context.getPointerType(originalTy)))
      return val;
  
  // Check for casts from pointers to integers.
  if (castTy->isIntegralOrEnumerationType() && Loc::isLocType(originalTy))
    return evalCastFromLoc(val.castAs<Loc>(), castTy);

  // Check for casts from integers to pointers.
  if (Loc::isLocType(castTy) && originalTy->isIntegralOrEnumerationType()) {
    if (Optional<nonloc::LocAsInteger> LV = val.getAs<nonloc::LocAsInteger>()) {
      if (const MemRegion *R = LV->getLoc().getAsRegion()) {
        StoreManager &storeMgr = StateMgr.getStoreManager();
        R = storeMgr.castRegion(R, castTy);
        return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
      }
      return LV->getLoc();
    }
    return dispatchCast(val, castTy);
  }

  // Just pass through function and block pointers.
  if (originalTy->isBlockPointerType() || originalTy->isFunctionPointerType()) {
    assert(Loc::isLocType(castTy));
    return val;
  }

  // Check for casts from array type to another type.
  if (const ArrayType *arrayT =
                      dyn_cast<ArrayType>(originalTy.getCanonicalType())) {
    // We will always decay to a pointer.
    QualType elemTy = arrayT->getElementType();
    val = StateMgr.ArrayToPointer(val.castAs<Loc>(), elemTy);

    // Are we casting from an array to a pointer?  If so just pass on
    // the decayed value.
    if (castTy->isPointerType() || castTy->isReferenceType())
      return val;

    // Are we casting from an array to an integer?  If so, cast the decayed
    // pointer value to an integer.
    assert(castTy->isIntegralOrEnumerationType());

    // FIXME: Keep these here for now in case we decide soon that we
    // need the original decayed type.
    //    QualType elemTy = cast<ArrayType>(originalTy)->getElementType();
    //    QualType pointerTy = C.getPointerType(elemTy);
    return evalCastFromLoc(val.castAs<Loc>(), castTy);
  }

  // Check for casts from a region to a specific type.
  if (const MemRegion *R = val.getAsRegion()) {
    // Handle other casts of locations to integers.
    if (castTy->isIntegralOrEnumerationType())
      return evalCastFromLoc(loc::MemRegionVal(R), castTy);

    // FIXME: We should handle the case where we strip off view layers to get
    //  to a desugared type.
    if (!Loc::isLocType(castTy)) {
      // FIXME: There can be gross cases where one casts the result of a function
      // (that returns a pointer) to some other value that happens to fit
      // within that pointer value.  We currently have no good way to
      // model such operations.  When this happens, the underlying operation
      // is that the caller is reasoning about bits.  Conceptually we are
      // layering a "view" of a location on top of those bits.  Perhaps
      // we need to be more lazy about mutual possible views, even on an
      // SVal?  This may be necessary for bit-level reasoning as well.
      return UnknownVal();
//.........这里部分代码省略.........

// FIXME: should rewrite according to the cast kind.
SVal SValBuilder::evalCast(SVal val, QualType castTy, QualType originalTy) {
  castTy = Context.getCanonicalType(castTy);
  originalTy = Context.getCanonicalType(originalTy);
  if (val.isUnknownOrUndef() || castTy == originalTy)
    return val;

  // For const casts, just propagate the value.
  if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
    if (haveSimilarTypes(Context, Context.getPointerType(castTy),
                                  Context.getPointerType(originalTy)))
      return val;
  
  // Check for casts from pointers to integers.
  if (castTy->isIntegerType() && Loc::isLocType(originalTy))
    return evalCastFromLoc(cast<Loc>(val), castTy);

  // Check for casts from integers to pointers.
  if (Loc::isLocType(castTy) && originalTy->isIntegerType()) {
    if (nonloc::LocAsInteger *LV = dyn_cast<nonloc::LocAsInteger>(&val)) {
      if (const MemRegion *R = LV->getLoc().getAsRegion()) {
        StoreManager &storeMgr = StateMgr.getStoreManager();
        R = storeMgr.castRegion(R, castTy);
        return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
      }
      return LV->getLoc();
    }
    return dispatchCast(val, castTy);
  }

  // Just pass through function and block pointers.
  if (originalTy->isBlockPointerType() || originalTy->isFunctionPointerType()) {
    assert(Loc::isLocType(castTy));
    return val;
  }

  // Check for casts from array type to another type.
  if (originalTy->isArrayType()) {
    // We will always decay to a pointer.
    val = StateMgr.ArrayToPointer(cast<Loc>(val));

    // Are we casting from an array to a pointer?  If so just pass on
    // the decayed value.
    if (castTy->isPointerType())
      return val;

    // Are we casting from an array to an integer?  If so, cast the decayed
    // pointer value to an integer.
    assert(castTy->isIntegerType());

    // FIXME: Keep these here for now in case we decide soon that we
    // need the original decayed type.
    //    QualType elemTy = cast<ArrayType>(originalTy)->getElementType();
    //    QualType pointerTy = C.getPointerType(elemTy);
    return evalCastFromLoc(cast<Loc>(val), castTy);
  }

  // Check for casts from a region to a specific type.
  if (const MemRegion *R = val.getAsRegion()) {
    // Handle other casts of locations to integers.
    if (castTy->isIntegerType())
      return evalCastFromLoc(loc::MemRegionVal(R), castTy);

    // FIXME: We should handle the case where we strip off view layers to get
    //  to a desugared type.
    if (!Loc::isLocType(castTy)) {
      // FIXME: There can be gross cases where one casts the result of a function
      // (that returns a pointer) to some other value that happens to fit
      // within that pointer value.  We currently have no good way to
      // model such operations.  When this happens, the underlying operation
      // is that the caller is reasoning about bits.  Conceptually we are
      // layering a "view" of a location on top of those bits.  Perhaps
      // we need to be more lazy about mutual possible views, even on an
      // SVal?  This may be necessary for bit-level reasoning as well.
      return UnknownVal();
    }

    // We get a symbolic function pointer for a dereference of a function
    // pointer, but it is of function type. Example:

    //  struct FPRec {
    //    void (*my_func)(int * x);
    //  };
    //
    //  int bar(int x);
    //
    //  int f1_a(struct FPRec* foo) {
    //    int x;
    //    (*foo->my_func)(&x);
    //    return bar(x)+1; // no-warning
    //  }

    assert(Loc::isLocType(originalTy) || originalTy->isFunctionType() ||
           originalTy->isBlockPointerType() || castTy->isReferenceType());

    StoreManager &storeMgr = StateMgr.getStoreManager();

    // Delegate to store manager to get the result of casting a region to a
    // different type.  If the MemRegion* returned is NULL, this expression
    // Evaluates to UnknownVal.
//.........这里部分代码省略.........