C++ SymbolSet::isEmpty方法代码示例

/// Remove the Value requiring a release from the tracked set for
/// Instance and return the resultant state.
ProgramStateRef ObjCDeallocChecker::removeValueRequiringRelease(
    ProgramStateRef State, SymbolRef Instance, SymbolRef Value) const {
  assert(Instance);
  assert(Value);
  const ObjCIvarRegion *RemovedRegion = getIvarRegionForIvarSymbol(Value);
  if (!RemovedRegion)
    return State;

  const SymbolSet *Unreleased = State->get<UnreleasedIvarMap>(Instance);
  if (!Unreleased)
    return State;

  // Mark the value as no longer requiring a release.
  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();
  SymbolSet NewUnreleased = *Unreleased;
  for (auto &Sym : *Unreleased) {
    const ObjCIvarRegion *UnreleasedRegion = getIvarRegionForIvarSymbol(Sym);
    assert(UnreleasedRegion);
    if (RemovedRegion->getDecl() == UnreleasedRegion->getDecl()) {
      NewUnreleased = F.remove(NewUnreleased, Sym);
    }
  }

  if (NewUnreleased.isEmpty()) {
    return State->remove<UnreleasedIvarMap>(Instance);
  }

  return State->set<UnreleasedIvarMap>(Instance, NewUnreleased);
}

/// If this is the beginning of -dealloc, mark the values initially stored in
/// instance variables that must be released by the end of -dealloc
/// as unreleased in the state.
void ObjCDeallocChecker::checkBeginFunction(
    CheckerContext &C) const {
  initIdentifierInfoAndSelectors(C.getASTContext());

  // Only do this if the current method is -dealloc.
  SVal SelfVal;
  if (!isInInstanceDealloc(C, SelfVal))
    return;

  SymbolRef SelfSymbol = SelfVal.getAsSymbol();

  const LocationContext *LCtx = C.getLocationContext();
  ProgramStateRef InitialState = C.getState();

  ProgramStateRef State = InitialState;

  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();

  // Symbols that must be released by the end of the -dealloc;
  SymbolSet RequiredReleases = F.getEmptySet();

  // If we're an inlined -dealloc, we should add our symbols to the existing
  // set from our subclass.
  if (const SymbolSet *CurrSet = State->get<UnreleasedIvarMap>(SelfSymbol))
    RequiredReleases = *CurrSet;

  for (auto *PropImpl : getContainingObjCImpl(LCtx)->property_impls()) {
    ReleaseRequirement Requirement = getDeallocReleaseRequirement(PropImpl);
    if (Requirement != ReleaseRequirement::MustRelease)
      continue;

    SVal LVal = State->getLValue(PropImpl->getPropertyIvarDecl(), SelfVal);
    Optional<Loc> LValLoc = LVal.getAs<Loc>();
    if (!LValLoc)
      continue;

    SVal InitialVal = State->getSVal(LValLoc.getValue());
    SymbolRef Symbol = InitialVal.getAsSymbol();
    if (!Symbol || !isa<SymbolRegionValue>(Symbol))
      continue;

    // Mark the value as requiring a release.
    RequiredReleases = F.add(RequiredReleases, Symbol);
  }

  if (!RequiredReleases.isEmpty()) {
    State = State->set<UnreleasedIvarMap>(SelfSymbol, RequiredReleases);
  }

  if (State != InitialState) {
    C.addTransition(State);
  }
}

//.........这里部分代码省略.........

  const SymbolSet *OldUnreleased = State->get<UnreleasedIvarMap>(SelfSym);
  if (!OldUnreleased)
    return;

  SymbolSet NewUnreleased = *OldUnreleased;
  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();

  ProgramStateRef InitialState = State;

  for (auto *IvarSymbol : *OldUnreleased) {
    const TypedValueRegion *TVR =
        cast<SymbolRegionValue>(IvarSymbol)->getRegion();
    const ObjCIvarRegion *IvarRegion = cast<ObjCIvarRegion>(TVR);

    // Don't warn if the ivar is not for this instance.
    if (SelfRegion != IvarRegion->getSuperRegion())
      continue;

    const ObjCIvarDecl *IvarDecl = IvarRegion->getDecl();
    // Prevent an inlined call to -dealloc in a super class from warning
    // about the values the subclass's -dealloc should release.
    if (IvarDecl->getContainingInterface() !=
        cast<ObjCMethodDecl>(LCtx->getDecl())->getClassInterface())
      continue;

    // Prevents diagnosing multiple times for the same instance variable
    // at, for example, both a return and at the end of the function.
    NewUnreleased = F.remove(NewUnreleased, IvarSymbol);

    if (State->getStateManager()
            .getConstraintManager()
            .isNull(State, IvarSymbol)
            .isConstrainedTrue()) {
      continue;
    }

    // A missing release manifests as a leak, so treat as a non-fatal error.
    if (!ErrNode)
      ErrNode = C.generateNonFatalErrorNode();
    // If we've already reached this node on another path, return without
    // diagnosing.
    if (!ErrNode)
      return;

    std::string Buf;
    llvm::raw_string_ostream OS(Buf);

    const ObjCInterfaceDecl *Interface = IvarDecl->getContainingInterface();
    // If the class is known to have a lifecycle with teardown that is
    // separate from -dealloc, do not warn about missing releases. We
    // suppress here (rather than not tracking for instance variables in
    // such classes) because these classes are rare.
    if (classHasSeparateTeardown(Interface))
      return;

    ObjCImplDecl *ImplDecl = Interface->getImplementation();

    const ObjCPropertyImplDecl *PropImpl =
        ImplDecl->FindPropertyImplIvarDecl(IvarDecl->getIdentifier());

    const ObjCPropertyDecl *PropDecl = PropImpl->getPropertyDecl();

    assert(PropDecl->getSetterKind() == ObjCPropertyDecl::Copy ||
           PropDecl->getSetterKind() == ObjCPropertyDecl::Retain);

    OS << "The '" << *IvarDecl << "' ivar in '" << *ImplDecl
       << "' was ";

    if (PropDecl->getSetterKind() == ObjCPropertyDecl::Retain)
      OS << "retained";
    else
      OS << "copied";

    OS << " by a synthesized property but not released"
          " before '[super dealloc]'";

    std::unique_ptr<BugReport> BR(
        new BugReport(*MissingReleaseBugType, OS.str(), ErrNode));

    C.emitReport(std::move(BR));
  }

  if (NewUnreleased.isEmpty()) {
    State = State->remove<UnreleasedIvarMap>(SelfSym);
  } else {
    State = State->set<UnreleasedIvarMap>(SelfSym, NewUnreleased);
  }

  if (ErrNode) {
    C.addTransition(State, ErrNode);
  } else if (State != InitialState) {
    C.addTransition(State);
  }

  // Make sure that after checking in the top-most frame the list of
  // tracked ivars is empty. This is intended to detect accidental leaks in
  // the UnreleasedIvarMap program state.
  assert(!LCtx->inTopFrame() || State->get<UnreleasedIvarMap>().isEmpty());
}