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 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 35 36 namespace clang { 37 38 class CFG; 39 40 namespace ento { 41 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 // ExplodedNode is not constified all over the engine because we need to add 51 // successors to it at any time after creating it. 52 53 class ExplodedNode : public llvm::FoldingSetNode { 54 friend class ExplodedGraph; 55 friend class CoreEngine; 56 friend class NodeBuilder; 57 friend class StmtNodeBuilder; 58 friend class BranchNodeBuilder; 59 friend class IndirectGotoNodeBuilder; 60 friend class SwitchNodeBuilder; 61 friend class EndOfFunctionNodeBuilder; 62 63 class NodeGroup { 64 enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 }; 65 uintptr_t P; 66 67 unsigned getKind() const { 68 return P & 0x1; 69 } 70 71 void *getPtr() const { 72 assert (!getFlag()); 73 return reinterpret_cast<void*>(P & ~Mask); 74 } 75 76 ExplodedNode *getNode() const { 77 return reinterpret_cast<ExplodedNode*>(getPtr()); 78 } 79 80 public: 81 NodeGroup() : P(0) {} 82 83 ExplodedNode **begin() const; 84 85 ExplodedNode **end() const; 86 87 unsigned size() const; 88 89 bool empty() const { return (P & ~Mask) == 0; } 90 91 void addNode(ExplodedNode *N, ExplodedGraph &G); 92 93 void replaceNode(ExplodedNode *node); 94 95 void setFlag() { 96 assert(P == 0); 97 P = AuxFlag; 98 } 99 100 bool getFlag() const { 101 return P & AuxFlag ? true : false; 102 } 103 }; 104 105 /// Location - The program location (within a function body) associated 106 /// with this node. 107 const ProgramPoint Location; 108 109 /// State - The state associated with this node. 110 const ProgramState *State; 111 112 /// Preds - The predecessors of this node. 113 NodeGroup Preds; 114 115 /// Succs - The successors of this node. 116 NodeGroup Succs; 117 118 public: 119 120 explicit ExplodedNode(const ProgramPoint &loc, const ProgramState *state) 121 : Location(loc), State(state) { 122 const_cast<ProgramState*>(State)->incrementReferenceCount(); 123 } 124 125 ~ExplodedNode() { 126 const_cast<ProgramState*>(State)->decrementReferenceCount(); 127 } 128 129 /// getLocation - Returns the edge associated with the given node. 130 ProgramPoint getLocation() const { return Location; } 131 132 const LocationContext *getLocationContext() const { 133 return getLocation().getLocationContext(); 134 } 135 136 const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); } 137 138 CFG &getCFG() const { return *getLocationContext()->getCFG(); } 139 140 ParentMap &getParentMap() const {return getLocationContext()->getParentMap();} 141 142 template <typename T> 143 T &getAnalysis() const { 144 return *getLocationContext()->getAnalysis<T>(); 145 } 146 147 const ProgramState *getState() const { return State; } 148 149 template <typename T> 150 const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); } 151 152 static void Profile(llvm::FoldingSetNodeID &ID, 153 const ProgramPoint &Loc, const ProgramState *state) { 154 ID.Add(Loc); 155 ID.AddPointer(state); 156 } 157 158 void Profile(llvm::FoldingSetNodeID& ID) const { 159 Profile(ID, getLocation(), getState()); 160 } 161 162 /// addPredeccessor - Adds a predecessor to the current node, and 163 /// in tandem add this node as a successor of the other node. 164 void addPredecessor(ExplodedNode *V, ExplodedGraph &G); 165 166 unsigned succ_size() const { return Succs.size(); } 167 unsigned pred_size() const { return Preds.size(); } 168 bool succ_empty() const { return Succs.empty(); } 169 bool pred_empty() const { return Preds.empty(); } 170 171 bool isSink() const { return Succs.getFlag(); } 172 void markAsSink() { Succs.setFlag(); } 173 174 ExplodedNode *getFirstPred() { 175 return pred_empty() ? NULL : *(pred_begin()); 176 } 177 178 const ExplodedNode *getFirstPred() const { 179 return const_cast<ExplodedNode*>(this)->getFirstPred(); 180 } 181 182 // Iterators over successor and predecessor vertices. 183 typedef ExplodedNode** succ_iterator; 184 typedef const ExplodedNode* const * const_succ_iterator; 185 typedef ExplodedNode** pred_iterator; 186 typedef const ExplodedNode* const * const_pred_iterator; 187 188 pred_iterator pred_begin() { return Preds.begin(); } 189 pred_iterator pred_end() { return Preds.end(); } 190 191 const_pred_iterator pred_begin() const { 192 return const_cast<ExplodedNode*>(this)->pred_begin(); 193 } 194 const_pred_iterator pred_end() const { 195 return const_cast<ExplodedNode*>(this)->pred_end(); 196 } 197 198 succ_iterator succ_begin() { return Succs.begin(); } 199 succ_iterator succ_end() { return Succs.end(); } 200 201 const_succ_iterator succ_begin() const { 202 return const_cast<ExplodedNode*>(this)->succ_begin(); 203 } 204 const_succ_iterator succ_end() const { 205 return const_cast<ExplodedNode*>(this)->succ_end(); 206 } 207 208 // For debugging. 209 210 public: 211 212 class Auditor { 213 public: 214 virtual ~Auditor(); 215 virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst) = 0; 216 }; 217 218 static void SetAuditor(Auditor* A); 219 220 private: 221 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); } 222 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); } 223 }; 224 225 // FIXME: Is this class necessary? 226 class InterExplodedGraphMap { 227 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M; 228 friend class ExplodedGraph; 229 230 public: 231 ExplodedNode *getMappedNode(const ExplodedNode *N) const; 232 233 InterExplodedGraphMap() {} 234 virtual ~InterExplodedGraphMap() {} 235 }; 236 237 class ExplodedGraph { 238 protected: 239 friend class CoreEngine; 240 241 // Type definitions. 242 typedef SmallVector<ExplodedNode*,2> RootsTy; 243 typedef SmallVector<ExplodedNode*,10> EndNodesTy; 244 245 /// Roots - The roots of the simulation graph. Usually there will be only 246 /// one, but clients are free to establish multiple subgraphs within a single 247 /// SimulGraph. Moreover, these subgraphs can often merge when paths from 248 /// different roots reach the same state at the same program location. 249 RootsTy Roots; 250 251 /// EndNodes - The nodes in the simulation graph which have been 252 /// specially marked as the endpoint of an abstract simulation path. 253 EndNodesTy EndNodes; 254 255 /// Nodes - The nodes in the graph. 256 llvm::FoldingSet<ExplodedNode> Nodes; 257 258 /// BVC - Allocator and context for allocating nodes and their predecessor 259 /// and successor groups. 260 BumpVectorContext BVC; 261 262 /// NumNodes - The number of nodes in the graph. 263 unsigned NumNodes; 264 265 /// A list of recently allocated nodes that can potentially be recycled. 266 void *recentlyAllocatedNodes; 267 268 /// A list of nodes that can be reused. 269 void *freeNodes; 270 271 /// A flag that indicates whether nodes should be recycled. 272 bool reclaimNodes; 273 274 public: 275 /// getNode - Retrieve the node associated with a (Location,State) pair, 276 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 277 /// this pair exists, it is created. IsNew is set to true if 278 /// the node was freshly created. 279 280 ExplodedNode *getNode(const ProgramPoint &L, const ProgramState *State, 281 bool* IsNew = 0); 282 283 ExplodedGraph* MakeEmptyGraph() const { 284 return new ExplodedGraph(); 285 } 286 287 /// addRoot - Add an untyped node to the set of roots. 288 ExplodedNode *addRoot(ExplodedNode *V) { 289 Roots.push_back(V); 290 return V; 291 } 292 293 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 294 ExplodedNode *addEndOfPath(ExplodedNode *V) { 295 EndNodes.push_back(V); 296 return V; 297 } 298 299 ExplodedGraph() 300 : NumNodes(0), recentlyAllocatedNodes(0), 301 freeNodes(0), reclaimNodes(false) {} 302 303 ~ExplodedGraph(); 304 305 unsigned num_roots() const { return Roots.size(); } 306 unsigned num_eops() const { return EndNodes.size(); } 307 308 bool empty() const { return NumNodes == 0; } 309 unsigned size() const { return NumNodes; } 310 311 // Iterators. 312 typedef ExplodedNode NodeTy; 313 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 314 typedef NodeTy** roots_iterator; 315 typedef NodeTy* const * const_roots_iterator; 316 typedef NodeTy** eop_iterator; 317 typedef NodeTy* const * const_eop_iterator; 318 typedef AllNodesTy::iterator node_iterator; 319 typedef AllNodesTy::const_iterator const_node_iterator; 320 321 node_iterator nodes_begin() { return Nodes.begin(); } 322 323 node_iterator nodes_end() { return Nodes.end(); } 324 325 const_node_iterator nodes_begin() const { return Nodes.begin(); } 326 327 const_node_iterator nodes_end() const { return Nodes.end(); } 328 329 roots_iterator roots_begin() { return Roots.begin(); } 330 331 roots_iterator roots_end() { return Roots.end(); } 332 333 const_roots_iterator roots_begin() const { return Roots.begin(); } 334 335 const_roots_iterator roots_end() const { return Roots.end(); } 336 337 eop_iterator eop_begin() { return EndNodes.begin(); } 338 339 eop_iterator eop_end() { return EndNodes.end(); } 340 341 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 342 343 const_eop_iterator eop_end() const { return EndNodes.end(); } 344 345 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 346 BumpVectorContext &getNodeAllocator() { return BVC; } 347 348 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 349 350 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 351 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 352 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 353 354 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 355 const ExplodedNode* const * NEnd, 356 InterExplodedGraphMap *M, 357 llvm::DenseMap<const void*, const void*> *InverseMap) const; 358 359 /// Enable tracking of recently allocated nodes for potential reclamation 360 /// when calling reclaimRecentlyAllocatedNodes(). 361 void enableNodeReclamation() { reclaimNodes = true; } 362 363 /// Reclaim "uninteresting" nodes created since the last time this method 364 /// was called. 365 void reclaimRecentlyAllocatedNodes(); 366 }; 367 368 class ExplodedNodeSet { 369 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 370 ImplTy Impl; 371 372 public: 373 ExplodedNodeSet(ExplodedNode *N) { 374 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 375 Impl.insert(N); 376 } 377 378 ExplodedNodeSet() {} 379 380 inline void Add(ExplodedNode *N) { 381 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 382 } 383 384 typedef ImplTy::iterator iterator; 385 typedef ImplTy::const_iterator const_iterator; 386 387 unsigned size() const { return Impl.size(); } 388 bool empty() const { return Impl.empty(); } 389 390 void clear() { Impl.clear(); } 391 void insert(const ExplodedNodeSet &S) { 392 if (empty()) 393 Impl = S.Impl; 394 else 395 Impl.insert(S.begin(), S.end()); 396 } 397 398 inline iterator begin() { return Impl.begin(); } 399 inline iterator end() { return Impl.end(); } 400 401 inline const_iterator begin() const { return Impl.begin(); } 402 inline const_iterator end() const { return Impl.end(); } 403 }; 404 405 } // end GR namespace 406 407 } // end clang namespace 408 409 // GraphTraits 410 411 namespace llvm { 412 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 413 typedef clang::ento::ExplodedNode NodeType; 414 typedef NodeType::succ_iterator ChildIteratorType; 415 typedef llvm::df_iterator<NodeType*> nodes_iterator; 416 417 static inline NodeType* getEntryNode(NodeType* N) { 418 return N; 419 } 420 421 static inline ChildIteratorType child_begin(NodeType* N) { 422 return N->succ_begin(); 423 } 424 425 static inline ChildIteratorType child_end(NodeType* N) { 426 return N->succ_end(); 427 } 428 429 static inline nodes_iterator nodes_begin(NodeType* N) { 430 return df_begin(N); 431 } 432 433 static inline nodes_iterator nodes_end(NodeType* N) { 434 return df_end(N); 435 } 436 }; 437 438 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 439 typedef const clang::ento::ExplodedNode NodeType; 440 typedef NodeType::const_succ_iterator ChildIteratorType; 441 typedef llvm::df_iterator<NodeType*> nodes_iterator; 442 443 static inline NodeType* getEntryNode(NodeType* N) { 444 return N; 445 } 446 447 static inline ChildIteratorType child_begin(NodeType* N) { 448 return N->succ_begin(); 449 } 450 451 static inline ChildIteratorType child_end(NodeType* N) { 452 return N->succ_end(); 453 } 454 455 static inline nodes_iterator nodes_begin(NodeType* N) { 456 return df_begin(N); 457 } 458 459 static inline nodes_iterator nodes_end(NodeType* N) { 460 return df_end(N); 461 } 462 }; 463 464 } // end llvm namespace 465 466 #endif 467
