CFRefCount.cpp

    isRetain = true;
  else if (S != ReleaseSelector)
    return true;
  
  // We have "Retain" or "Release".  Get the reference binding.
  
  ValueStateManager& StateMgr = Eng.getStateManager();
  ValueState* St = Builder.GetState(Pred);
  RVal V = StateMgr.GetRVal(St, Receiver);
  
  if (!isa<lval::SymbolVal>(V))
    return true;

  SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
  RefBindings B = GetRefBindings(*St);
  
  RefBindings::TreeTy* T = B.SlimFind(Sym);
  
  if (!T)
    return true;
  
  RefVal::Kind hasErr = (RefVal::Kind) 0;
  B = Update(B, Sym, T->getValue().second, isRetain ? IncRef : DecRef, hasErr);

  // Create a new state with the updated bindings.
  
  ValueState StVals = *St;
  SetRefBindings(StVals, B);
  St = StateMgr.getPersistentState(StVals);
  
  // Create an error node if it exists.
  
  if (hasErr)
    ProcessNonLeakError(Dst, Builder, ME, Receiver, Pred, St, hasErr);
  else
    Builder.MakeNode(Dst, ME, Pred, St);

  return false;
}

// Stores.

void CFRefCount::EvalStore(ExplodedNodeSet<ValueState>& Dst,
                           GRExprEngine& Eng,
                           GRStmtNodeBuilder<ValueState>& Builder,
                           Expr* E, ExplodedNode<ValueState>* Pred,
                           ValueState* St, RVal TargetLV, RVal Val) {
  
  // Check if we have a binding for "Val" and if we are storing it to something
  // we don't understand or otherwise the value "escapes" the function.
  
  if (!isa<lval::SymbolVal>(Val))
    return;
  
  // Are we storing to something that causes the value to "escape"?
  
  bool escapes = false;
  
  if (!isa<lval::DeclVal>(TargetLV))
    escapes = true;
  else
    escapes = cast<lval::DeclVal>(TargetLV).getDecl()->hasGlobalStorage();
  
  if (!escapes)
    return;
  
  SymbolID Sym = cast<lval::SymbolVal>(Val).getSymbol();
  RefBindings B = GetRefBindings(*St);
  RefBindings::TreeTy* T = B.SlimFind(Sym);
  
  if (!T)
    return;
  
  // Nuke the binding.  
  St = NukeBinding(Eng.getStateManager(), St, Sym);
  
  // Hand of the remaining logic to the parent implementation.
  GRSimpleVals::EvalStore(Dst, Eng, Builder, E, Pred, St, TargetLV, Val);
}


ValueState* CFRefCount::NukeBinding(ValueStateManager& VMgr, ValueState* St,
                                    SymbolID sid) {
  ValueState StImpl = *St;
  RefBindings B = GetRefBindings(StImpl);
  StImpl.CheckerState = RefBFactory.Remove(B, sid).getRoot();
  return VMgr.getPersistentState(StImpl);
}

// End-of-path.



ValueState* CFRefCount::HandleSymbolDeath(ValueStateManager& VMgr,
                                          ValueState* St, SymbolID sid,
                                          RefVal V, bool& hasLeak) {
    
  hasLeak = V.isOwned() || 
            ((V.isNotOwned() || V.isReturnedOwned()) && V.getCount() > 0);

  if (!hasLeak)
    return NukeBinding(VMgr, St, sid);
  
  RefBindings B = GetRefBindings(*St);
  ValueState StImpl = *St;  
  StImpl.CheckerState = RefBFactory.Add(B, sid, RefVal::makeLeak()).getRoot();
  return VMgr.getPersistentState(StImpl);
}

void CFRefCount::EvalEndPath(GRExprEngine& Eng,
                             GREndPathNodeBuilder<ValueState>& Builder) {
  
  ValueState* St = Builder.getState();
  RefBindings B = GetRefBindings(*St);
  
  llvm::SmallVector<SymbolID, 10> Leaked;
  
  for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
    bool hasLeak = false;
    
    St = HandleSymbolDeath(Eng.getStateManager(), St,
                           (*I).first, (*I).second, hasLeak);
    
    if (hasLeak) Leaked.push_back((*I).first);
  }
      
  ExplodedNode<ValueState>* N = Builder.MakeNode(St);
  
  for (llvm::SmallVector<SymbolID, 10>::iterator I=Leaked.begin(),
       E = Leaked.end(); I != E; ++I)
    Leaks.push_back(std::make_pair(*I, N));
}

 // Return statements.

void CFRefCount::EvalReturn(ExplodedNodeSet<ValueState>& Dst,
                            GRExprEngine& Eng,
                            GRStmtNodeBuilder<ValueState>& Builder,
                            ReturnStmt* S,
                            ExplodedNode<ValueState>* Pred) {
  
  Expr* RetE = S->getRetValue();
  if (!RetE) return;
  
  ValueStateManager& StateMgr = Eng.getStateManager();
  ValueState* St = Builder.GetState(Pred);
  RVal V = StateMgr.GetRVal(St, RetE);
  
  if (!isa<lval::SymbolVal>(V))
    return;
  
  // Get the reference count binding (if any).
  SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
  RefBindings B = GetRefBindings(*St);
  RefBindings::TreeTy* T = B.SlimFind(Sym);
  
  if (!T)
    return;
  
  // Change the reference count.
  
  RefVal X = T->getValue().second;  
  
  switch (X.getKind()) {
      
    case RefVal::Owned: { 
      unsigned cnt = X.getCount();
      X = RefVal::makeReturnedOwned(cnt);
      break;
    }
      
    case RefVal::NotOwned: {
      unsigned cnt = X.getCount();
      X = cnt ? RefVal::makeReturnedOwned(cnt - 1)
              : RefVal::makeReturnedNotOwned();
      break;
    }
      
    default: 
      // None of the error states should be possible at this point.
      // A symbol could not have been leaked (yet) if we are returning it
      // (and thus it is still live), and the other errors are hard errors.
      assert(false);
      return;
  }
  
  // Update the binding.

  ValueState StImpl = *St;
  StImpl.CheckerState = RefBFactory.Add(B, Sym, X).getRoot();        
  Builder.MakeNode(Dst, S, Pred, StateMgr.getPersistentState(StImpl));
}


CFRefCount::RefBindings CFRefCount::Update(RefBindings B, SymbolID sym,
                                           RefVal V, ArgEffect E,
                                           RefVal::Kind& hasErr) {
  
  // FIXME: This dispatch can potentially be sped up by unifiying it into
  //  a single switch statement.  Opt for simplicity for now.
  
  switch (E) {
    default:
      assert (false && "Unhandled CFRef transition.");
      
    case DoNothing:
      if (V.getKind() == RefVal::Released) {
        V = RefVal::makeUseAfterRelease();        
        hasErr = V.getKind();
        break;
      }
      
      return B;
      
    case IncRef:      
      switch (V.getKind()) {
        default:
          assert(false);

        case RefVal::Owned:
          V = RefVal::makeOwned(V.getCount()+1);
          break;
                    
        case RefVal::NotOwned:
          V = RefVal::makeNotOwned(V.getCount()+1);
          break;
          
        case RefVal::Released:
          V = RefVal::makeUseAfterRelease();
          hasErr = V.getKind();
          break;
      }
      
      break;
      
    case DecRef:
      switch (V.getKind()) {
        default:
          assert (false);
          
        case RefVal::Owned: {
          unsigned Count = V.getCount();
          V = Count > 0 ? RefVal::makeOwned(Count - 1) : RefVal::makeReleased();
          break;
        }
          
        case RefVal::NotOwned: {
          unsigned Count = V.getCount();
          
          if (Count > 0)
            V = RefVal::makeNotOwned(Count - 1);
          else {
            V = RefVal::makeReleaseNotOwned();
            hasErr = V.getKind();
          }
          
          break;
        }

        case RefVal::Released:
          V = RefVal::makeUseAfterRelease();
          hasErr = V.getKind();
          break;          
      }
      
      break;
  }

  return RefBFactory.Add(B, sym, V);
}


//===----------------------------------------------------------------------===//
// Error reporting.
//===----------------------------------------------------------------------===//

void UseAfterRelease::EmitWarnings(BugReporter& BR) {

  for (CFRefCount::use_after_iterator I = TF.use_after_begin(),
        E = TF.use_after_end(); I != E; ++I) {
    
    RangedBugReport report(*this, I->first);
    report.addRange(I->second->getSourceRange());    
    BR.EmitWarning(report);    
  }
}

void BadRelease::EmitWarnings(BugReporter& BR) {
  
  for (CFRefCount::bad_release_iterator I = TF.bad_release_begin(),
       E = TF.bad_release_end(); I != E; ++I) {
    
    RangedBugReport report(*this, I->first);
    report.addRange(I->second->getSourceRange());    
    BR.EmitWarning(report); 

  }  
}

void Leak::EmitWarnings(BugReporter& BR) {
  
  for (CFRefCount::leaks_iterator I = TF.leaks_begin(),
       E = TF.leaks_end(); I != E; ++I) {
    
    BugReport report(*this, I->second);
    BR.EmitWarning(report);     
  }  
}

//===----------------------------------------------------------------------===//
// Transfer function creation for external clients.
//===----------------------------------------------------------------------===//

GRTransferFuncs* clang::MakeCFRefCountTF(ASTContext& Ctx) {
  return new CFRefCount(Ctx);
}