include/clang/StaticAnalyzer/EntoSA/PathSensitive/ExplodedGraph.h

   1 //=-- ExplodedGraph.h - Local, Path-Sens. "Exploded Graph" -*- C++ -*-------==//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file defines the template classes ExplodedNode and ExplodedGraph,
  11 //  which represent a path-sensitive, intra-procedural "exploded graph."
  12 //  See "Precise interprocedural dataflow analysis via graph reachability"
  13 //  by Reps, Horwitz, and Sagiv
  14 //  (http://portal.acm.org/citation.cfm?id=199462) for the definition of an
  15 //  exploded graph.
  16 //
  17 //===----------------------------------------------------------------------===//
  18
  19 #ifndef LLVM_CLANG_GR_EXPLODEDGRAPH
  20 #define LLVM_CLANG_GR_EXPLODEDGRAPH
  21
  22 #include "clang/Analysis/ProgramPoint.h"
  23 #include "clang/Analysis/AnalysisContext.h"
  24 #include "clang/AST/Decl.h"
  25 #include "llvm/ADT/SmallVector.h"
  26 #include "llvm/ADT/FoldingSet.h"
  27 #include "llvm/ADT/SmallPtrSet.h"
  28 #include "llvm/Support/Allocator.h"
  29 #include "llvm/ADT/OwningPtr.h"
  30 #include "llvm/ADT/GraphTraits.h"
  31 #include "llvm/ADT/DepthFirstIterator.h"
  32 #include "llvm/Support/Casting.h"
  33 #include "clang/Analysis/Support/BumpVector.h"
  34
  35 namespace clang {
  36
  37 class CFG;
  38
  39 namespace ento {
  40
  41 class GRState;
  42 class ExplodedGraph;
  43
  44 //===----------------------------------------------------------------------===//
  45 // ExplodedGraph "implementation" classes.  These classes are not typed to
  46 // contain a specific kind of state.  Typed-specialized versions are defined
  47 // on top of these classes.
  48 //===----------------------------------------------------------------------===//
  49
  50 class ExplodedNode : public llvm::FoldingSetNode {
  51   friend class ExplodedGraph;
  52   friend class CoreEngine;
  53   friend class StmtNodeBuilder;
  54   friend class BranchNodeBuilder;
  55   friend class IndirectGotoNodeBuilder;
  56   friend class SwitchNodeBuilder;
  57   friend class EndPathNodeBuilder;
  58
  59   class NodeGroup {
  60     enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 };
  61     uintptr_t P;
  62
  63     unsigned getKind() const {
  64       return P & 0x1;
  65     }
  66
  67     void* getPtr() const {
  68       assert (!getFlag());
  69       return reinterpret_cast<void*>(P & ~Mask);
  70     }
  71
  72     ExplodedNode *getNode() const {
  73       return reinterpret_cast<ExplodedNode*>(getPtr());
  74     }
  75
  76   public:
  77     NodeGroup() : P(0) {}
  78
  79     ExplodedNode **begin() const;
  80
  81     ExplodedNode **end() const;
  82
  83     unsigned size() const;
  84
  85     bool empty() const { return (P & ~Mask) == 0; }
  86
  87     void addNode(ExplodedNode* N, ExplodedGraph &G);
  88
  89     void setFlag() {
  90       assert(P == 0);
  91       P = AuxFlag;
  92     }
  93
  94     bool getFlag() const {
  95       return P & AuxFlag ? true : false;
  96     }
  97   };
  98
  99   /// Location - The program location (within a function body) associated
 100   ///  with this node.
 101   const ProgramPoint Location;
 102
 103   /// State - The state associated with this node.
 104   const GRState* State;
 105
 106   /// Preds - The predecessors of this node.
 107   NodeGroup Preds;
 108
 109   /// Succs - The successors of this node.
 110   NodeGroup Succs;
 111
 112 public:
 113
 114   explicit ExplodedNode(const ProgramPoint& loc, const GRState* state)
 115     : Location(loc), State(state) {}
 116
 117   /// getLocation - Returns the edge associated with the given node.
 118   ProgramPoint getLocation() const { return Location; }
 119
 120   const LocationContext *getLocationContext() const {
 121     return getLocation().getLocationContext();
 122   }
 123
 124   const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); }
 125
 126   CFG &getCFG() const { return *getLocationContext()->getCFG(); }
 127
 128   ParentMap &getParentMap() const {return getLocationContext()->getParentMap();}
 129
 130   LiveVariables &getLiveVariables() const {
 131     return *getLocationContext()->getLiveVariables();
 132   }
 133
 134   const GRState* getState() const { return State; }
 135
 136   template <typename T>
 137   const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); }
 138
 139   static void Profile(llvm::FoldingSetNodeID &ID,
 140                       const ProgramPoint& Loc, const GRState* state) {
 141     ID.Add(Loc);
 142     ID.AddPointer(state);
 143   }
 144
 145   void Profile(llvm::FoldingSetNodeID& ID) const {
 146     Profile(ID, getLocation(), getState());
 147   }
 148
 149   /// addPredeccessor - Adds a predecessor to the current node, and
 150   ///  in tandem add this node as a successor of the other node.
 151   void addPredecessor(ExplodedNode* V, ExplodedGraph &G);
 152
 153   unsigned succ_size() const { return Succs.size(); }
 154   unsigned pred_size() const { return Preds.size(); }
 155   bool succ_empty() const { return Succs.empty(); }
 156   bool pred_empty() const { return Preds.empty(); }
 157
 158   bool isSink() const { return Succs.getFlag(); }
 159   void markAsSink() { Succs.setFlag(); }
 160
 161   ExplodedNode* getFirstPred() {
 162     return pred_empty() ? NULL : *(pred_begin());
 163   }
 164
 165   const ExplodedNode* getFirstPred() const {
 166     return const_cast<ExplodedNode*>(this)->getFirstPred();
 167   }
 168
 169   // Iterators over successor and predecessor vertices.
 170   typedef ExplodedNode**       succ_iterator;
 171   typedef const ExplodedNode* const * const_succ_iterator;
 172   typedef ExplodedNode**       pred_iterator;
 173   typedef const ExplodedNode* const * const_pred_iterator;
 174
 175   pred_iterator pred_begin() { return Preds.begin(); }
 176   pred_iterator pred_end() { return Preds.end(); }
 177
 178   const_pred_iterator pred_begin() const {
 179     return const_cast<ExplodedNode*>(this)->pred_begin();
 180   }
 181   const_pred_iterator pred_end() const {
 182     return const_cast<ExplodedNode*>(this)->pred_end();
 183   }
 184
 185   succ_iterator succ_begin() { return Succs.begin(); }
 186   succ_iterator succ_end() { return Succs.end(); }
 187
 188   const_succ_iterator succ_begin() const {
 189     return const_cast<ExplodedNode*>(this)->succ_begin();
 190   }
 191   const_succ_iterator succ_end() const {
 192     return const_cast<ExplodedNode*>(this)->succ_end();
 193   }
 194
 195   // For debugging.
 196
 197 public:
 198
 199   class Auditor {
 200   public:
 201     virtual ~Auditor();
 202     virtual void AddEdge(ExplodedNode* Src, ExplodedNode* Dst) = 0;
 203   };
 204
 205   static void SetAuditor(Auditor* A);
 206 };
 207
 208 // FIXME: Is this class necessary?
 209 class InterExplodedGraphMap {
 210   llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M;
 211   friend class ExplodedGraph;
 212
 213 public:
 214   ExplodedNode* getMappedNode(const ExplodedNode* N) const;
 215
 216   InterExplodedGraphMap() {}
 217   virtual ~InterExplodedGraphMap() {}
 218 };
 219
 220 class ExplodedGraph {
 221 protected:
 222   friend class CoreEngine;
 223
 224   // Type definitions.
 225   typedef llvm::SmallVector<ExplodedNode*,2>    RootsTy;
 226   typedef llvm::SmallVector<ExplodedNode*,10>   EndNodesTy;
 227
 228   /// Roots - The roots of the simulation graph. Usually there will be only
 229   /// one, but clients are free to establish multiple subgraphs within a single
 230   /// SimulGraph. Moreover, these subgraphs can often merge when paths from
 231   /// different roots reach the same state at the same program location.
 232   RootsTy Roots;
 233
 234   /// EndNodes - The nodes in the simulation graph which have been
 235   ///  specially marked as the endpoint of an abstract simulation path.
 236   EndNodesTy EndNodes;
 237
 238   /// Nodes - The nodes in the graph.
 239   llvm::FoldingSet<ExplodedNode> Nodes;
 240
 241   /// BVC - Allocator and context for allocating nodes and their predecessor
 242   /// and successor groups.
 243   BumpVectorContext BVC;
 244
 245   /// NumNodes - The number of nodes in the graph.
 246   unsigned NumNodes;
 247
 248 public:
 249   /// getNode - Retrieve the node associated with a (Location,State) pair,
 250   ///  where the 'Location' is a ProgramPoint in the CFG.  If no node for
 251   ///  this pair exists, it is created.  IsNew is set to true if
 252   ///  the node was freshly created.
 253
 254   ExplodedNode* getNode(const ProgramPoint& L, const GRState *State,
 255                         bool* IsNew = 0);
 256
 257   ExplodedGraph* MakeEmptyGraph() const {
 258     return new ExplodedGraph();
 259   }
 260
 261   /// addRoot - Add an untyped node to the set of roots.
 262   ExplodedNode* addRoot(ExplodedNode* V) {
 263     Roots.push_back(V);
 264     return V;
 265   }
 266
 267   /// addEndOfPath - Add an untyped node to the set of EOP nodes.
 268   ExplodedNode* addEndOfPath(ExplodedNode* V) {
 269     EndNodes.push_back(V);
 270     return V;
 271   }
 272
 273   ExplodedGraph() : NumNodes(0) {}
 274
 275   ~ExplodedGraph() {}
 276
 277   unsigned num_roots() const { return Roots.size(); }
 278   unsigned num_eops() const { return EndNodes.size(); }
 279
 280   bool empty() const { return NumNodes == 0; }
 281   unsigned size() const { return NumNodes; }
 282
 283   // Iterators.
 284   typedef ExplodedNode                        NodeTy;
 285   typedef llvm::FoldingSet<ExplodedNode>      AllNodesTy;
 286   typedef NodeTy**                            roots_iterator;
 287   typedef NodeTy* const *                     const_roots_iterator;
 288   typedef NodeTy**                            eop_iterator;
 289   typedef NodeTy* const *                     const_eop_iterator;
 290   typedef AllNodesTy::iterator                node_iterator;
 291   typedef AllNodesTy::const_iterator          const_node_iterator;
 292
 293   node_iterator nodes_begin() { return Nodes.begin(); }
 294
 295   node_iterator nodes_end() { return Nodes.end(); }
 296
 297   const_node_iterator nodes_begin() const { return Nodes.begin(); }
 298
 299   const_node_iterator nodes_end() const { return Nodes.end(); }
 300
 301   roots_iterator roots_begin() { return Roots.begin(); }
 302
 303   roots_iterator roots_end() { return Roots.end(); }
 304
 305   const_roots_iterator roots_begin() const { return Roots.begin(); }
 306
 307   const_roots_iterator roots_end() const { return Roots.end(); }
 308
 309   eop_iterator eop_begin() { return EndNodes.begin(); }
 310
 311   eop_iterator eop_end() { return EndNodes.end(); }
 312
 313   const_eop_iterator eop_begin() const { return EndNodes.begin(); }
 314
 315   const_eop_iterator eop_end() const { return EndNodes.end(); }
 316
 317   llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); }
 318   BumpVectorContext &getNodeAllocator() { return BVC; }
 319
 320   typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap;
 321
 322   std::pair<ExplodedGraph*, InterExplodedGraphMap*>
 323   Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd,
 324        llvm::DenseMap<const void*, const void*> *InverseMap = 0) const;
 325
 326   ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg,
 327                               const ExplodedNode* const * NEnd,
 328                               InterExplodedGraphMap *M,
 329                     llvm::DenseMap<const void*, const void*> *InverseMap) const;
 330 };
 331
 332 class ExplodedNodeSet {
 333   typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy;
 334   ImplTy Impl;
 335
 336 public:
 337   ExplodedNodeSet(ExplodedNode* N) {
 338     assert (N && !static_cast<ExplodedNode*>(N)->isSink());
 339     Impl.insert(N);
 340   }
 341
 342   ExplodedNodeSet() {}
 343
 344   inline void Add(ExplodedNode* N) {
 345     if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N);
 346   }
 347
 348   ExplodedNodeSet& operator=(const ExplodedNodeSet &X) {
 349     Impl = X.Impl;
 350     return *this;
 351   }
 352
 353   typedef ImplTy::iterator       iterator;
 354   typedef ImplTy::const_iterator const_iterator;
 355
 356   unsigned size() const { return Impl.size();  }
 357   bool empty()    const { return Impl.empty(); }
 358
 359   void clear() { Impl.clear(); }
 360   void insert(const ExplodedNodeSet &S) {
 361     if (empty())
 362       Impl = S.Impl;
 363     else
 364       Impl.insert(S.begin(), S.end());
 365   }
 366
 367   inline iterator begin() { return Impl.begin(); }
 368   inline iterator end()   { return Impl.end();   }
 369
 370   inline const_iterator begin() const { return Impl.begin(); }
 371   inline const_iterator end()   const { return Impl.end();   }
 372 };
 373
 374 } // end GR namespace
 375
 376 } // end clang namespace
 377
 378 // GraphTraits
 379
 380 namespace llvm {
 381   template<> struct GraphTraits<clang::ento::ExplodedNode*> {
 382     typedef clang::ento::ExplodedNode NodeType;
 383     typedef NodeType::succ_iterator  ChildIteratorType;
 384     typedef llvm::df_iterator<NodeType*>      nodes_iterator;
 385
 386     static inline NodeType* getEntryNode(NodeType* N) {
 387       return N;
 388     }
 389
 390     static inline ChildIteratorType child_begin(NodeType* N) {
 391       return N->succ_begin();
 392     }
 393
 394     static inline ChildIteratorType child_end(NodeType* N) {
 395       return N->succ_end();
 396     }
 397
 398     static inline nodes_iterator nodes_begin(NodeType* N) {
 399       return df_begin(N);
 400     }
 401
 402     static inline nodes_iterator nodes_end(NodeType* N) {
 403       return df_end(N);
 404     }
 405   };
 406
 407   template<> struct GraphTraits<const clang::ento::ExplodedNode*> {
 408     typedef const clang::ento::ExplodedNode NodeType;
 409     typedef NodeType::const_succ_iterator   ChildIteratorType;
 410     typedef llvm::df_iterator<NodeType*>       nodes_iterator;
 411
 412     static inline NodeType* getEntryNode(NodeType* N) {
 413       return N;
 414     }
 415
 416     static inline ChildIteratorType child_begin(NodeType* N) {
 417       return N->succ_begin();
 418     }
 419
 420     static inline ChildIteratorType child_end(NodeType* N) {
 421       return N->succ_end();
 422     }
 423
 424     static inline nodes_iterator nodes_begin(NodeType* N) {
 425       return df_begin(N);
 426     }
 427
 428     static inline nodes_iterator nodes_end(NodeType* N) {
 429       return df_end(N);
 430     }
 431   };
 432
 433 } // end llvm namespace
 434
 435 #endif