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