GRExprEngine.cpp

    }
  }
}

GRExprEngine::StateTy GRExprEngine::Assume(StateTy St, NonLValue Cond,
                                         bool Assumption, 
                                         bool& isFeasible) {
  
  assert (!isa<UninitializedVal>(Cond));
  
  if (isa<UnknownVal>(Cond)) {
    isFeasible = true;
    return St;  
  }
  
  switch (Cond.getSubKind()) {
    default:
      assert (false && "'Assume' not implemented for this NonLValue.");
      return St;
      
      
    case nonlval::SymbolValKind: {
      nonlval::SymbolVal& SV = cast<nonlval::SymbolVal>(Cond);
      SymbolID sym = SV.getSymbol();
      
      if (Assumption)
        return AssumeSymNE(St, sym, ValMgr.getValue(0, SymMgr.getType(sym)),
                           isFeasible);
      else
        return AssumeSymEQ(St, sym, ValMgr.getValue(0, SymMgr.getType(sym)),
                           isFeasible);
    }
      
    case nonlval::SymIntConstraintValKind:
      return
        AssumeSymInt(St, Assumption,
                     cast<nonlval::SymIntConstraintVal>(Cond).getConstraint(),
                     isFeasible);
      
    case nonlval::ConcreteIntKind: {
      bool b = cast<nonlval::ConcreteInt>(Cond).getValue() != 0;
      isFeasible = b ? Assumption : !Assumption;      
      return St;
    }
  }
}

GRExprEngine::StateTy
GRExprEngine::AssumeSymNE(StateTy St, SymbolID sym,
                         const llvm::APSInt& V, bool& isFeasible) {
  
  // First, determine if sym == X, where X != V.
  if (const llvm::APSInt* X = St.getSymVal(sym)) {
    isFeasible = *X != V;
    return St;
  }
  
  // Second, determine if sym != V.
  if (St.isNotEqual(sym, V)) {
    isFeasible = true;
    return St;
  }
      
  // If we reach here, sym is not a constant and we don't know if it is != V.
  // Make that assumption.
  
  isFeasible = true;
  return StateMgr.AddNE(St, sym, V);
}

GRExprEngine::StateTy
GRExprEngine::AssumeSymEQ(StateTy St, SymbolID sym,
                         const llvm::APSInt& V, bool& isFeasible) {
  
  // First, determine if sym == X, where X != V.
  if (const llvm::APSInt* X = St.getSymVal(sym)) {
    isFeasible = *X == V;
    return St;
  }
  
  // Second, determine if sym != V.
  if (St.isNotEqual(sym, V)) {
    isFeasible = false;
    return St;
  }
  
  // If we reach here, sym is not a constant and we don't know if it is == V.
  // Make that assumption.
  
  isFeasible = true;
  return StateMgr.AddEQ(St, sym, V);
}

GRExprEngine::StateTy
GRExprEngine::AssumeSymInt(StateTy St, bool Assumption,
                          const SymIntConstraint& C, bool& isFeasible) {
  
  switch (C.getOpcode()) {
    default:
      // No logic yet for other operators.
      return St;
      
    case BinaryOperator::EQ:
      if (Assumption)
        return AssumeSymEQ(St, C.getSymbol(), C.getInt(), isFeasible);
      else
        return AssumeSymNE(St, C.getSymbol(), C.getInt(), isFeasible);
      
    case BinaryOperator::NE:
      if (Assumption)
        return AssumeSymNE(St, C.getSymbol(), C.getInt(), isFeasible);
      else
        return AssumeSymEQ(St, C.getSymbol(), C.getInt(), isFeasible);
  }
}

//===----------------------------------------------------------------------===//
// Visualization.
//===----------------------------------------------------------------------===//

#ifndef NDEBUG
static GRExprEngine* GraphPrintCheckerState;

namespace llvm {
template<>
struct VISIBILITY_HIDDEN DOTGraphTraits<GRExprEngine::NodeTy*> :
  public DefaultDOTGraphTraits {
    
  static void PrintVarBindings(std::ostream& Out, GRExprEngine::StateTy St) {

    Out << "Variables:\\l";
    
    bool isFirst = true;
    
    for (GRExprEngine::StateTy::vb_iterator I=St.vb_begin(),
                                           E=St.vb_end(); I!=E;++I) {        

      if (isFirst)
        isFirst = false;
      else
        Out << "\\l";
      
      Out << ' ' << I.getKey()->getName() << " : ";
      I.getData().print(Out);
    }
    
  }
    
    
  static void PrintSubExprBindings(std::ostream& Out, GRExprEngine::StateTy St){
    
    bool isFirst = true;
    
    for (GRExprEngine::StateTy::seb_iterator I=St.seb_begin(), E=St.seb_end();
                                            I != E;++I) {        
      
      if (isFirst) {
        Out << "\\l\\lSub-Expressions:\\l";
        isFirst = false;
      }
      else
        Out << "\\l";
      
      Out << " (" << (void*) I.getKey() << ") ";
      I.getKey()->printPretty(Out);
      Out << " : ";
      I.getData().print(Out);
    }
  }
    
  static void PrintBlkExprBindings(std::ostream& Out, GRExprEngine::StateTy St){
        
    bool isFirst = true;

    for (GRExprEngine::StateTy::beb_iterator I=St.beb_begin(), E=St.beb_end();
                                            I != E; ++I) {      
      if (isFirst) {
        Out << "\\l\\lBlock-level Expressions:\\l";
        isFirst = false;
      }
      else
        Out << "\\l";

      Out << " (" << (void*) I.getKey() << ") ";
      I.getKey()->printPretty(Out);
      Out << " : ";
      I.getData().print(Out);
    }
  }
    
  static void PrintEQ(std::ostream& Out, GRExprEngine::StateTy St) {
    ValueState::ConstantEqTy CE = St.getImpl()->ConstantEq;
    
    if (CE.isEmpty())
      return;
    
    Out << "\\l\\|'==' constraints:";

    for (ValueState::ConstantEqTy::iterator I=CE.begin(), E=CE.end(); I!=E;++I)
      Out << "\\l $" << I.getKey() << " : " << I.getData()->toString();
  }
    
  static void PrintNE(std::ostream& Out, GRExprEngine::StateTy St) {
    ValueState::ConstantNotEqTy NE = St.getImpl()->ConstantNotEq;
    
    if (NE.isEmpty())
      return;
    
    Out << "\\l\\|'!=' constraints:";
    
    for (ValueState::ConstantNotEqTy::iterator I=NE.begin(), EI=NE.end();
         I != EI; ++I){
      
      Out << "\\l $" << I.getKey() << " : ";
      bool isFirst = true;
      
      ValueState::IntSetTy::iterator J=I.getData().begin(),
                                    EJ=I.getData().end();      
      for ( ; J != EJ; ++J) {        
        if (isFirst) isFirst = false;
        else Out << ", ";
        
        Out << (*J)->toString();
      }    
    }
  }
    
  static std::string getNodeAttributes(const GRExprEngine::NodeTy* N, void*) {
    
    if (GraphPrintCheckerState->isImplicitNullDeref(N) ||
        GraphPrintCheckerState->isExplicitNullDeref(N) ||
        GraphPrintCheckerState->isUninitStore(N) ||
        GraphPrintCheckerState->isUninitControlFlow(N))
      return "color=\"red\",style=\"filled\"";
    
    return "";
  }
    
  static std::string getNodeLabel(const GRExprEngine::NodeTy* N, void*) {
    std::ostringstream Out;

    // Program Location.
    ProgramPoint Loc = N->getLocation();
    
    switch (Loc.getKind()) {
      case ProgramPoint::BlockEntranceKind:
        Out << "Block Entrance: B" 
            << cast<BlockEntrance>(Loc).getBlock()->getBlockID();
        break;
      
      case ProgramPoint::BlockExitKind:
        assert (false);
        break;
        
      case ProgramPoint::PostStmtKind: {
        const PostStmt& L = cast<PostStmt>(Loc);
        Out << L.getStmt()->getStmtClassName() << ':' 
            << (void*) L.getStmt() << ' ';
        
        L.getStmt()->printPretty(Out);
        
        if (GraphPrintCheckerState->isImplicitNullDeref(N)) {
          Out << "\\|Implicit-Null Dereference.\\l";
        }
        else if (GraphPrintCheckerState->isExplicitNullDeref(N)) {
          Out << "\\|Explicit-Null Dereference.\\l";
        }
        else if (GraphPrintCheckerState->isUninitStore(N)) {
          Out << "\\|Store to Uninitialized LValue.";
        }
        
        break;
      }
    
      default: {
        const BlockEdge& E = cast<BlockEdge>(Loc);
        Out << "Edge: (B" << E.getSrc()->getBlockID() << ", B"
            << E.getDst()->getBlockID()  << ')';
        
        if (Stmt* T = E.getSrc()->getTerminator()) {
          Out << "\\|Terminator: ";
          E.getSrc()->printTerminator(Out);
          
          if (isa<SwitchStmt>(T)) {
            Stmt* Label = E.getDst()->getLabel();
            
            if (Label) {                        
              if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) {
                Out << "\\lcase ";
                C->getLHS()->printPretty(Out);
                
                if (Stmt* RHS = C->getRHS()) {
                  Out << " .. ";
                  RHS->printPretty(Out);
                }
                
                Out << ":";
              }
              else {
                assert (isa<DefaultStmt>(Label));
                Out << "\\ldefault:";
              }
            }
            else 
              Out << "\\l(implicit) default:";
          }
          else if (isa<IndirectGotoStmt>(T)) {
            // FIXME
          }
          else {
            Out << "\\lCondition: ";
            if (*E.getSrc()->succ_begin() == E.getDst())
              Out << "true";
            else
              Out << "false";                        
          }
          
          Out << "\\l";
        }
        
        if (GraphPrintCheckerState->isUninitControlFlow(N)) {
          Out << "\\|Control-flow based on\\lUninitialized value.\\l";
        }
      }
    }
    
    Out << "\\|StateID: " << (void*) N->getState().getImpl() << "\\|";

    N->getState().printDOT(Out);
      
    Out << "\\l";
    return Out.str();
  }
};
} // end llvm namespace    
#endif

void GRExprEngine::ViewGraph() {
#ifndef NDEBUG
  GraphPrintCheckerState = this;
  llvm::ViewGraph(*G.roots_begin(), "GRExprEngine");
  GraphPrintCheckerState = NULL;
#endif
}