C++ SymbolReaper类代码示例

void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                     CheckerContext &C) const {
  // TODO: Clean up the state.
  for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
         E = SymReaper.dead_end(); I != E; ++I) {
    SymbolRef Sym = *I;
    ProgramStateRef state = C.getState();
    const StreamState *SS = state->get<StreamMap>(Sym);
    // TODO: Shouldn't we have a continue here?
    if (!SS)
      return;

    if (SS->isOpened()) {
      ExplodedNode *N = C.generateSink();
      if (N) {
        if (!BT_ResourceLeak)
          BT_ResourceLeak.reset(new BuiltinBug("Resource Leak", 
                         "Opened File never closed. Potential Resource leak."));
        BugReport *R = new BugReport(*BT_ResourceLeak, 
                                     BT_ResourceLeak->getDescription(), N);
        C.emitReport(R);
      }
    }
  }
}

void DynamicTypePropagation::checkDeadSymbols(SymbolReaper &SR,
                                              CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  DynamicTypeMapImpl TypeMap = State->get<DynamicTypeMap>();
  for (DynamicTypeMapImpl::iterator I = TypeMap.begin(), E = TypeMap.end();
       I != E; ++I) {
    if (!SR.isLiveRegion(I->first)) {
      State = State->remove<DynamicTypeMap>(I->first);
    }
  }

  if (!SR.hasDeadSymbols()) {
    C.addTransition(State);
    return;
  }

  MostSpecializedTypeArgsMapTy TyArgMap =
      State->get<MostSpecializedTypeArgsMap>();
  for (MostSpecializedTypeArgsMapTy::iterator I = TyArgMap.begin(),
                                              E = TyArgMap.end();
       I != E; ++I) {
    if (SR.isDead(I->first)) {
      State = State->remove<MostSpecializedTypeArgsMap>(I->first);
    }
  }

  C.addTransition(State);
}

/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef 
BasicConstraintManager::removeDeadBindings(ProgramStateRef state,
                                           SymbolReaper& SymReaper) {

  ConstEqTy CE = state->get<ConstEq>();
  ConstEqTy::Factory& CEFactory = state->get_context<ConstEq>();

  for (ConstEqTy::iterator I = CE.begin(), E = CE.end(); I!=E; ++I) {
    SymbolRef sym = I.getKey();
    if (SymReaper.maybeDead(sym))
      CE = CEFactory.remove(CE, sym);
  }
  state = state->set<ConstEq>(CE);

  ConstNotEqTy CNE = state->get<ConstNotEq>();
  ConstNotEqTy::Factory& CNEFactory = state->get_context<ConstNotEq>();

  for (ConstNotEqTy::iterator I = CNE.begin(), E = CNE.end(); I != E; ++I) {
    SymbolRef sym = I.getKey();
    if (SymReaper.maybeDead(sym))
      CNE = CNEFactory.remove(CNE, sym);
  }

  return state->set<ConstNotEq>(CNE);
}

void IteratorChecker::checkDeadSymbols(SymbolReaper &SR,
                                       CheckerContext &C) const {
  // Cleanup
  auto State = C.getState();

  auto RegionMap = State->get<IteratorRegionMap>();
  for (const auto Reg : RegionMap) {
    if (!SR.isLiveRegion(Reg.first)) {
      State = State->remove<IteratorRegionMap>(Reg.first);
    }
  }

  auto SymbolMap = State->get<IteratorSymbolMap>();
  for (const auto Sym : SymbolMap) {
    if (!SR.isLive(Sym.first)) {
      State = State->remove<IteratorSymbolMap>(Sym.first);
    }
  }

  auto ContMap = State->get<ContainerMap>();
  for (const auto Cont : ContMap) {
    if (!SR.isLiveRegion(Cont.first)) {
      State = State->remove<ContainerMap>(Cont.first);
    }
  }

  auto ComparisonMap = State->get<IteratorComparisonMap>();
  for (const auto Comp : ComparisonMap) {
    if (!SR.isLive(Comp.first)) {
      State = State->remove<IteratorComparisonMap>(Comp.first);
    }
  }
}

Environment
EnvironmentManager::RemoveDeadBindings(Environment Env, const Stmt *S,
                                       SymbolReaper &SymReaper,
                                       const GRState *ST,
                              llvm::SmallVectorImpl<const MemRegion*> &DRoots) {

  CFG &C = *Env.getAnalysisContext().getCFG();

  // We construct a new Environment object entirely, as this is cheaper than
  // individually removing all the subexpression bindings (which will greatly
  // outnumber block-level expression bindings).
  Environment NewEnv = getInitialEnvironment(&Env.getAnalysisContext());

  // Iterate over the block-expr bindings.
  for (Environment::iterator I = Env.begin(), E = Env.end();
       I != E; ++I) {

    const Stmt *BlkExpr = I.getKey();

    // Not a block-level expression?
    if (!C.isBlkExpr(BlkExpr))
      continue;

    const SVal &X = I.getData();

    if (SymReaper.isLive(S, BlkExpr)) {
      // Copy the binding to the new map.
      NewEnv.ExprBindings = F.Add(NewEnv.ExprBindings, BlkExpr, X);

      // If the block expr's value is a memory region, then mark that region.
      if (isa<loc::MemRegionVal>(X)) {
        const MemRegion* R = cast<loc::MemRegionVal>(X).getRegion();
        DRoots.push_back(R);
        // Mark the super region of the RX as live.
        // e.g.: int x; char *y = (char*) &x; if (*y) ...
        // 'y' => element region. 'x' is its super region.
        // We only add one level super region for now.

        // FIXME: maybe multiple level of super regions should be added.
        if (const SubRegion *SR = dyn_cast<SubRegion>(R))
          DRoots.push_back(SR->getSuperRegion());
      }

      // Mark all symbols in the block expr's value live.
      MarkLiveCallback cb(SymReaper);
      ST->scanReachableSymbols(X, cb);
      continue;
    }

    // Otherwise the expression is dead with a couple exceptions.
    // Do not misclean LogicalExpr or ConditionalOperator.  It is dead at the
    // beginning of itself, but we need its UndefinedVal to determine its
    // SVal.
    if (X.isUndef() && cast<UndefinedVal>(X).getData())
      NewEnv.ExprBindings = F.Add(NewEnv.ExprBindings, BlkExpr, X);
  }

  return NewEnv;
}

// removeDeadBindings:
//  - Remove subexpression bindings.
//  - Remove dead block expression bindings.
//  - Keep live block expression bindings:
//   - Mark their reachable symbols live in SymbolReaper,
//     see ScanReachableSymbols.
//   - Mark the region in DRoots if the binding is a loc::MemRegionVal.
Environment
EnvironmentManager::removeDeadBindings(Environment Env,
                                       SymbolReaper &SymReaper,
                                       ProgramStateRef ST) {

  // We construct a new Environment object entirely, as this is cheaper than
  // individually removing all the subexpression bindings (which will greatly
  // outnumber block-level expression bindings).
  Environment NewEnv = getInitialEnvironment();

  MarkLiveCallback CB(SymReaper);
  ScanReachableSymbols RSScaner(ST, CB);

  llvm::ImmutableMapRef<EnvironmentEntry,SVal>
    EBMapRef(NewEnv.ExprBindings.getRootWithoutRetain(),
             F.getTreeFactory());

  // Iterate over the block-expr bindings.
  for (Environment::iterator I = Env.begin(), E = Env.end();
       I != E; ++I) {

    const EnvironmentEntry &BlkExpr = I.getKey();
    const SVal &X = I.getData();

    if (SymReaper.isLive(BlkExpr.getStmt(), BlkExpr.getLocationContext())) {
      // Copy the binding to the new map.
      EBMapRef = EBMapRef.add(BlkExpr, X);

      // If the block expr's value is a memory region, then mark that region.
      if (Optional<loc::MemRegionVal> R = X.getAs<loc::MemRegionVal>())
        SymReaper.markLive(R->getRegion());

      // Mark all symbols in the block expr's value live.
      RSScaner.scan(X);
      continue;
    } else {
      SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
      for (; SI != SE; ++SI)
        SymReaper.maybeDead(*SI);
    }
  }

  NewEnv.ExprBindings = EBMapRef.asImmutableMap();
  return NewEnv;
}

void MoveChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                   CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  TrackedRegionMapTy TrackedRegions = State->get<TrackedRegionMap>();
  for (TrackedRegionMapTy::value_type E : TrackedRegions) {
    const MemRegion *Region = E.first;
    bool IsRegDead = !SymReaper.isLiveRegion(Region);

    // Remove the dead regions from the region map.
    if (IsRegDead) {
      State = State->remove<TrackedRegionMap>(Region);
    }
  }
  C.addTransition(State);
}

static bool IsLiveRegion(SymbolReaper &Reaper, const MemRegion *MR) {
  MR = MR->getBaseRegion();

  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
    return Reaper.isLive(SR->getSymbol());

  if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
    return Reaper.isLive(VR);

  // FIXME: This is a gross over-approximation. What we really need is a way to
  // tell if anything still refers to this region. Unlike SymbolicRegions,
  // AllocaRegions don't have associated symbols, though, so we don't actually
  // have a way to track their liveness.
  if (isa<AllocaRegion>(MR))
    return true;

  if (isa<CXXThisRegion>(MR))
    return true;

  if (isa<MemSpaceRegion>(MR))
    return true;

  return false;
}

/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef 
RangeConstraintManager::removeDeadBindings(ProgramStateRef state,
                                           SymbolReaper& SymReaper) {

  ConstraintRangeTy CR = state->get<ConstraintRange>();
  ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();

  for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
    SymbolRef sym = I.getKey();
    if (SymReaper.maybeDead(sym))
      CR = CRFactory.remove(CR, sym);
  }

  return state->set<ConstraintRange>(CR);
}

void InnerPointerChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                           CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  PtrSet::Factory &F = State->getStateManager().get_context<PtrSet>();
  RawPtrMapTy RPM = State->get<RawPtrMap>();
  for (const auto Entry : RPM) {
    if (!SymReaper.isLiveRegion(Entry.first)) {
      // Due to incomplete destructor support, some dead regions might
      // remain in the program state map. Clean them up.
      State = State->remove<RawPtrMap>(Entry.first);
    }
    if (const PtrSet *OldSet = State->get<RawPtrMap>(Entry.first)) {
      PtrSet CleanedUpSet = *OldSet;
      for (const auto Symbol : Entry.second) {
        if (!SymReaper.isLive(Symbol))
          CleanedUpSet = F.remove(CleanedUpSet, Symbol);
      }
      State = CleanedUpSet.isEmpty()
                  ? State->remove<RawPtrMap>(Entry.first)
                  : State->set<RawPtrMap>(Entry.first, CleanedUpSet);
    }
  }
  C.addTransition(State);
}

void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                     CheckerContext &C) const {
  // TODO: Clean up the state.
  for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
         E = SymReaper.dead_end(); I != E; ++I) {
    SymbolRef Sym = *I;
    ProgramStateRef state = C.getState();
    const StreamState *SS = state->get<StreamMap>(Sym);
    if (!SS)
      continue;

    if (SS->isOpened()) {
      ExplodedNode *N = C.generateErrorNode();
      if (N) {
        if (!BT_ResourceLeak)
          BT_ResourceLeak.reset(new BuiltinBug(
              this, "Resource Leak",
              "Opened File never closed. Potential Resource leak."));
        C.emitReport(llvm::make_unique<BugReport>(
            *BT_ResourceLeak, BT_ResourceLeak->getDescription(), N));
      }
    }
  }
}

void ObjCLoopChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                       CheckerContext &C) const {
    ProgramStateRef State = C.getState();

    // Remove the dead symbols from the collection count map.
    ContainerCountMapTy Tracked = State->get<ContainerCountMap>();
    for (ContainerCountMapTy::iterator I = Tracked.begin(),
            E = Tracked.end(); I != E; ++I) {
        SymbolRef Sym = I->first;
        if (SymReaper.isDead(Sym))
            State = State->remove<ContainerCountMap>(Sym);
    }

    C.addTransition(State);
}

/// Cleaning up the program state.
void NullabilityChecker::checkDeadSymbols(SymbolReaper &SR,
                                          CheckerContext &C) const {
  if (!SR.hasDeadSymbols())
    return;

  ProgramStateRef State = C.getState();
  NullabilityMapTy Nullabilities = State->get<NullabilityMap>();
  for (NullabilityMapTy::iterator I = Nullabilities.begin(),
                                  E = Nullabilities.end();
       I != E; ++I) {
    const auto *Region = I->first->getAs<SymbolicRegion>();
    assert(Region && "Non-symbolic region is tracked.");
    if (SR.isDead(Region->getSymbol())) {
      State = State->remove<NullabilityMap>(I->first);
    }
  }
  // When one of the nonnull arguments are constrained to be null, nullability
  // preconditions are violated. It is not enough to check this only when we
  // actually report an error, because at that time interesting symbols might be
  // reaped.
  if (checkPreconditionViolation(State, C.getPredecessor(), C))
    return;
  C.addTransition(State);
}

void MPIChecker::checkMissingWaits(SymbolReaper &SymReaper,
                                   CheckerContext &Ctx) const {
  if (!SymReaper.hasDeadSymbols())
    return;

  ProgramStateRef State = Ctx.getState();
  const auto &Requests = State->get<RequestMap>();
  if (Requests.isEmpty())
    return;

  static CheckerProgramPointTag Tag("MPI-Checker", "MissingWait");
  ExplodedNode *ErrorNode{nullptr};

  auto ReqMap = State->get<RequestMap>();
  for (const auto &Req : ReqMap) {
    if (!SymReaper.isLiveRegion(Req.first)) {
      if (Req.second.CurrentState == Request::State::Nonblocking) {

        if (!ErrorNode) {
          ErrorNode = Ctx.generateNonFatalErrorNode(State, &Tag);
          State = ErrorNode->getState();
        }
        BReporter.reportMissingWait(Req.second, Req.first, ErrorNode,
                                    Ctx.getBugReporter());
      }
      State = State->remove<RequestMap>(Req.first);
    }
  }

  // Transition to update the state regarding removed requests.
  if (!ErrorNode) {
    Ctx.addTransition(State);
  } else {
    Ctx.addTransition(State, ErrorNode);
  }
}

/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef
RangeConstraintManager::removeDeadBindings(ProgramStateRef State,
                                           SymbolReaper &SymReaper) {
  bool Changed = false;
  ConstraintRangeTy CR = State->get<ConstraintRange>();
  ConstraintRangeTy::Factory &CRFactory = State->get_context<ConstraintRange>();

  for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
    SymbolRef Sym = I.getKey();
    if (SymReaper.maybeDead(Sym)) {
      Changed = true;
      CR = CRFactory.remove(CR, Sym);
    }
  }

  return Changed ? State->set<ConstraintRange>(CR) : State;
}