C++ CheckerContext::getCurrentAnalysisDeclContext方法代码示例

void ObjCSelfInitChecker::checkPostObjCMessage(ObjCMessage msg,
                                               CheckerContext &C) const {
  // When encountering a message that does initialization (init rule),
  // tag the return value so that we know later on that if self has this value
  // then it is properly initialized.

  // FIXME: A callback should disable checkers at the start of functions.
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
                                     C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  if (isInitMessage(msg)) {
    // Tag the return value as the result of an initializer.
    const ProgramState *state = C.getState();
    
    // FIXME this really should be context sensitive, where we record
    // the current stack frame (for IPA).  Also, we need to clean this
    // value out when we return from this method.
    state = state->set<CalledInit>(true);
    
    SVal V = state->getSVal(msg.getOriginExpr(), C.getLocationContext());
    addSelfFlag(state, V, SelfFlag_InitRes, C);
    return;
  }

  // We don't check for an invalid 'self' in an obj-c message expression to cut
  // down false positives where logging functions get information from self
  // (like its class) or doing "invalidation" on self when the initialization
  // fails.
}

void ObjCSelfInitChecker::checkPostCall(const CallEvent &CE,
                                        CheckerContext &C) const {
  // FIXME: A callback should disable checkers at the start of functions.
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
                                 C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  ProgramStateRef state = C.getState();
  SelfFlagEnum prevFlags = (SelfFlagEnum)state->get<PreCallSelfFlags>();
  if (!prevFlags)
    return;
  state = state->remove<PreCallSelfFlags>();

  unsigned NumArgs = CE.getNumArgs();
  for (unsigned i = 0; i < NumArgs; ++i) {
    SVal argV = CE.getArgSVal(i);
    if (isSelfVar(argV, C)) {
      // If the address of 'self' is being passed to the call, assume that the
      // 'self' after the call will have the same flags.
      // EX: log(&self)
      addSelfFlag(state, state->getSVal(cast<Loc>(argV)), prevFlags, C);
      return;
    } else if (hasSelfFlag(argV, SelfFlag_Self, C)) {
      // If 'self' is passed to the call by value, assume that the function
      // returns 'self'. So assign the flags, which were set on 'self' to the
      // return value.
      // EX: self = performMoreInitialization(self)
      addSelfFlag(state, CE.getReturnValue(), prevFlags, C);
      return;
    }
  }

  C.addTransition(state);
}

void ObjCSelfInitChecker::checkPreCall(const CallEvent &CE,
                                       CheckerContext &C) const {
  // FIXME: A callback should disable checkers at the start of functions.
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
                                 C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  ProgramStateRef state = C.getState();
  unsigned NumArgs = CE.getNumArgs();
  // If we passed 'self' as and argument to the call, record it in the state
  // to be propagated after the call.
  // Note, we could have just given up, but try to be more optimistic here and
  // assume that the functions are going to continue initialization or will not
  // modify self.
  for (unsigned i = 0; i < NumArgs; ++i) {
    SVal argV = CE.getArgSVal(i);
    if (isSelfVar(argV, C)) {
      unsigned selfFlags = getSelfFlags(state->getSVal(cast<Loc>(argV)), C);
      C.addTransition(state->set<PreCallSelfFlags>(selfFlags));
      return;
    } else if (hasSelfFlag(argV, SelfFlag_Self, C)) {
      unsigned selfFlags = getSelfFlags(argV, C);
      C.addTransition(state->set<PreCallSelfFlags>(selfFlags));
      return;
    }
  }
}

 void DanglingDelegateChecker::resetInitialStateIfNeeded(CheckerContext &context) const {
   // nothing to do if we did it already
   ProgramStateRef state = context.getState();
   if (state->get<InitStateWasSet>()) {
     return;
   }
   // record the InterfaceDecl if any
   const ObjCInterfaceDecl *topInterface = getCurrentTopClassInterface(context);
   if (topInterface) {
     state = state->set<CurrentObjCInterfaceDecl>((void *)topInterface);
     // see if we are in a 'pseudo-init' method
     const ObjCMethodDecl *decl = dyn_cast_or_null<ObjCMethodDecl>(context.getCurrentAnalysisDeclContext()->getDecl());
     if (decl) {
       const ObjCImplFacts *facts = getCurrentFacts(topInterface);
       if (facts && facts->_pseudoInitMethods.find(decl->getNameAsString()) != facts->_pseudoInitMethods.end()) {
         // override the maps to assume that everything was cleared already
         const std::map<const ObjCIvarDecl *, IvarFacts> &ivarFactsMap = facts->_ivarFactsMap;
         for (auto it = ivarFactsMap.begin(), end = ivarFactsMap.end(); it != end; ++it) {
           state = state->set<IvarMap>(it->first, IvarDynamicState(it->second));
         }
       }
     }
   }
   // in any case mark the state as initialized
   state = state->set<InitStateWasSet>(true);
   context.addTransition(state);
 }

void ObjCSelfInitChecker::checkPreStmt(const ReturnStmt *S,
                                       CheckerContext &C) const {
  // FIXME: A callback should disable checkers at the start of functions.
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
                                     C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  checkForInvalidSelf(S->getRetValue(), C,
    "Returning 'self' while it is not set to the result of "
                                                 "'[(super or self) init...]'");
}

void ObjCSelfInitChecker::checkPostStmt(const ObjCIvarRefExpr *E,
                                        CheckerContext &C) const {
  // FIXME: A callback should disable checkers at the start of functions.
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
                                     C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  checkForInvalidSelf(E->getBase(), C,
    "Instance variable used while 'self' is not set to the result of "
                                                 "'[(super or self) init...]'");
}

/// \brief Returns true if the location is 'self'.
static bool isSelfVar(SVal location, CheckerContext &C) {
  AnalysisDeclContext *analCtx = C.getCurrentAnalysisDeclContext(); 
  if (!analCtx->getSelfDecl())
    return false;
  if (!isa<loc::MemRegionVal>(location))
    return false;

  loc::MemRegionVal MRV = cast<loc::MemRegionVal>(location);
  if (const DeclRegion *DR = dyn_cast<DeclRegion>(MRV.getRegion()))
    return (DR->getDecl() == analCtx->getSelfDecl());

  return false;
}

void ObjCSelfInitChecker::checkLocation(SVal location, bool isLoad,
                                        const Stmt *S,
                                        CheckerContext &C) const {
  if (!shouldRunOnFunctionOrMethod(dyn_cast<NamedDecl>(
        C.getCurrentAnalysisDeclContext()->getDecl())))
    return;

  // Tag the result of a load from 'self' so that we can easily know that the
  // value is the object that 'self' points to.
  ProgramStateRef state = C.getState();
  if (isSelfVar(location, C))
    addSelfFlag(state, state->getSVal(location.castAs<Loc>()), SelfFlag_Self,
                C);
}

void IdempotentOperationChecker::checkPreStmt(const BinaryOperator *B,
                                              CheckerContext &C) const {
  // Find or create an entry in the hash for this BinaryOperator instance.
  // If we haven't done a lookup before, it will get default initialized to
  // 'Possible'. At this stage we do not store the ExplodedNode, as it has not
  // been created yet.
  BinaryOperatorData &Data = hash[B];
  Assumption &A = Data.assumption;
  AnalysisDeclContext *AC = C.getCurrentAnalysisDeclContext();

  // If we already have visited this node on a path that does not contain an
  // idempotent operation, return immediately.
  if (A == Impossible)
    return;

  // Retrieve both sides of the operator and determine if they can vary (which
  // may mean this is a false positive.
  const Expr *LHS = B->getLHS();
  const Expr *RHS = B->getRHS();

  // At this stage we can calculate whether each side contains a false positive
  // that applies to all operators. We only need to calculate this the first
  // time.
  bool LHSContainsFalsePositive = false, RHSContainsFalsePositive = false;
  if (A == Possible) {
    // An expression contains a false positive if it can't vary, or if it
    // contains a known false positive VarDecl.
    LHSContainsFalsePositive = !CanVary(LHS, AC)
        || containsNonLocalVarDecl(LHS);
    RHSContainsFalsePositive = !CanVary(RHS, AC)
        || containsNonLocalVarDecl(RHS);
  }

  ProgramStateRef state = C.getState();
  const LocationContext *LCtx = C.getLocationContext();
  SVal LHSVal = state->getSVal(LHS, LCtx);
  SVal RHSVal = state->getSVal(RHS, LCtx);

  // If either value is unknown, we can't be 100% sure of all paths.
  if (LHSVal.isUnknownOrUndef() || RHSVal.isUnknownOrUndef()) {
    A = Impossible;
    return;
  }
  BinaryOperator::Opcode Op = B->getOpcode();

  // Dereference the LHS SVal if this is an assign operation
  switch (Op) {
  default:
    break;

  // Fall through intentional
  case BO_AddAssign:
  case BO_SubAssign:
  case BO_MulAssign:
  case BO_DivAssign:
  case BO_AndAssign:
  case BO_OrAssign:
  case BO_XorAssign:
  case BO_ShlAssign:
  case BO_ShrAssign:
  case BO_Assign:
  // Assign statements have one extra level of indirection
    if (!isa<Loc>(LHSVal)) {
      A = Impossible;
      return;
    }
    LHSVal = state->getSVal(cast<Loc>(LHSVal), LHS->getType());
  }


  // We now check for various cases which result in an idempotent operation.

  // x op x
  switch (Op) {
  default:
    break; // We don't care about any other operators.

  // Fall through intentional
  case BO_Assign:
    // x Assign x can be used to silence unused variable warnings intentionally.
    // If this is a self assignment and the variable is referenced elsewhere,
    // and the assignment is not a truncation or extension, then it is a false
    // positive.
    if (isSelfAssign(LHS, RHS)) {
      if (!isUnused(LHS, AC) && !isTruncationExtensionAssignment(LHS, RHS)) {
        UpdateAssumption(A, Equal);
        return;
      }
      else {
        A = Impossible;
        return;
      }
    }

  case BO_SubAssign:
  case BO_DivAssign:
  case BO_AndAssign:
  case BO_OrAssign:
  case BO_XorAssign:
  case BO_Sub:
//.........这里部分代码省略.........