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/GRState.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 StmtNodeBuilder; 57 friend class BranchNodeBuilder; 58 friend class IndirectGotoNodeBuilder; 59 friend class SwitchNodeBuilder; 60 friend class EndOfFunctionNodeBuilder; 61 62 class NodeGroup { 63 enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 }; 64 uintptr_t P; 65 66 unsigned getKind() const { 67 return P & 0x1; 68 } 69 70 void* getPtr() const { 71 assert (!getFlag()); 72 return reinterpret_cast<void*>(P & ~Mask); 73 } 74 75 ExplodedNode *getNode() const { 76 return reinterpret_cast<ExplodedNode*>(getPtr()); 77 } 78 79 public: 80 NodeGroup() : P(0) {} 81 82 ExplodedNode **begin() const; 83 84 ExplodedNode **end() const; 85 86 unsigned size() const; 87 88 bool empty() const { return (P & ~Mask) == 0; } 89 90 void addNode(ExplodedNode* N, ExplodedGraph &G); 91 92 void replaceNode(ExplodedNode *node); 93 94 void setFlag() { 95 assert(P == 0); 96 P = AuxFlag; 97 } 98 99 bool getFlag() const { 100 return P & AuxFlag ? true : false; 101 } 102 }; 103 104 /// Location - The program location (within a function body) associated 105 /// with this node. 106 const ProgramPoint Location; 107 108 /// State - The state associated with this node. 109 const GRState* State; 110 111 /// Preds - The predecessors of this node. 112 NodeGroup Preds; 113 114 /// Succs - The successors of this node. 115 NodeGroup Succs; 116 117 public: 118 119 explicit ExplodedNode(const ProgramPoint& loc, const GRState* state) 120 : Location(loc), State(state) { 121 const_cast<GRState*>(State)->incrementReferenceCount(); 122 } 123 124 ~ExplodedNode() { 125 const_cast<GRState*>(State)->decrementReferenceCount(); 126 } 127 128 /// getLocation - Returns the edge associated with the given node. 129 ProgramPoint getLocation() const { return Location; } 130 131 const LocationContext *getLocationContext() const { 132 return getLocation().getLocationContext(); 133 } 134 135 const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); } 136 137 CFG &getCFG() const { return *getLocationContext()->getCFG(); } 138 139 ParentMap &getParentMap() const {return getLocationContext()->getParentMap();} 140 141 LiveVariables &getLiveVariables() const { 142 return *getLocationContext()->getLiveVariables(); 143 } 144 145 const GRState* getState() const { return State; } 146 147 template <typename T> 148 const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); } 149 150 static void Profile(llvm::FoldingSetNodeID &ID, 151 const ProgramPoint& Loc, const GRState* state) { 152 ID.Add(Loc); 153 ID.AddPointer(state); 154 } 155 156 void Profile(llvm::FoldingSetNodeID& ID) const { 157 Profile(ID, getLocation(), getState()); 158 } 159 160 /// addPredeccessor - Adds a predecessor to the current node, and 161 /// in tandem add this node as a successor of the other node. 162 void addPredecessor(ExplodedNode* V, ExplodedGraph &G); 163 164 unsigned succ_size() const { return Succs.size(); } 165 unsigned pred_size() const { return Preds.size(); } 166 bool succ_empty() const { return Succs.empty(); } 167 bool pred_empty() const { return Preds.empty(); } 168 169 bool isSink() const { return Succs.getFlag(); } 170 void markAsSink() { Succs.setFlag(); } 171 172 ExplodedNode* getFirstPred() { 173 return pred_empty() ? NULL : *(pred_begin()); 174 } 175 176 const ExplodedNode* getFirstPred() const { 177 return const_cast<ExplodedNode*>(this)->getFirstPred(); 178 } 179 180 // Iterators over successor and predecessor vertices. 181 typedef ExplodedNode** succ_iterator; 182 typedef const ExplodedNode* const * const_succ_iterator; 183 typedef ExplodedNode** pred_iterator; 184 typedef const ExplodedNode* const * const_pred_iterator; 185 186 pred_iterator pred_begin() { return Preds.begin(); } 187 pred_iterator pred_end() { return Preds.end(); } 188 189 const_pred_iterator pred_begin() const { 190 return const_cast<ExplodedNode*>(this)->pred_begin(); 191 } 192 const_pred_iterator pred_end() const { 193 return const_cast<ExplodedNode*>(this)->pred_end(); 194 } 195 196 succ_iterator succ_begin() { return Succs.begin(); } 197 succ_iterator succ_end() { return Succs.end(); } 198 199 const_succ_iterator succ_begin() const { 200 return const_cast<ExplodedNode*>(this)->succ_begin(); 201 } 202 const_succ_iterator succ_end() const { 203 return const_cast<ExplodedNode*>(this)->succ_end(); 204 } 205 206 // For debugging. 207 208 public: 209 210 class Auditor { 211 public: 212 virtual ~Auditor(); 213 virtual void AddEdge(ExplodedNode* Src, ExplodedNode* Dst) = 0; 214 }; 215 216 static void SetAuditor(Auditor* A); 217 218 private: 219 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); } 220 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); } 221 }; 222 223 // FIXME: Is this class necessary? 224 class InterExplodedGraphMap { 225 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M; 226 friend class ExplodedGraph; 227 228 public: 229 ExplodedNode* getMappedNode(const ExplodedNode* N) const; 230 231 InterExplodedGraphMap() {} 232 virtual ~InterExplodedGraphMap() {} 233 }; 234 235 class ExplodedGraph { 236 protected: 237 friend class CoreEngine; 238 239 // Type definitions. 240 typedef llvm::SmallVector<ExplodedNode*,2> RootsTy; 241 typedef llvm::SmallVector<ExplodedNode*,10> EndNodesTy; 242 243 /// Roots - The roots of the simulation graph. Usually there will be only 244 /// one, but clients are free to establish multiple subgraphs within a single 245 /// SimulGraph. Moreover, these subgraphs can often merge when paths from 246 /// different roots reach the same state at the same program location. 247 RootsTy Roots; 248 249 /// EndNodes - The nodes in the simulation graph which have been 250 /// specially marked as the endpoint of an abstract simulation path. 251 EndNodesTy EndNodes; 252 253 /// Nodes - The nodes in the graph. 254 llvm::FoldingSet<ExplodedNode> Nodes; 255 256 /// BVC - Allocator and context for allocating nodes and their predecessor 257 /// and successor groups. 258 BumpVectorContext BVC; 259 260 /// NumNodes - The number of nodes in the graph. 261 unsigned NumNodes; 262 263 /// A list of recently allocated nodes that can potentially be recycled. 264 void *recentlyAllocatedNodes; 265 266 /// A list of nodes that can be reused. 267 void *freeNodes; 268 269 /// A flag that indicates whether nodes should be recycled. 270 bool reclaimNodes; 271 272 public: 273 /// getNode - Retrieve the node associated with a (Location,State) pair, 274 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 275 /// this pair exists, it is created. IsNew is set to true if 276 /// the node was freshly created. 277 278 ExplodedNode* getNode(const ProgramPoint& L, const GRState *State, 279 bool* IsNew = 0); 280 281 ExplodedGraph* MakeEmptyGraph() const { 282 return new ExplodedGraph(); 283 } 284 285 /// addRoot - Add an untyped node to the set of roots. 286 ExplodedNode* addRoot(ExplodedNode* V) { 287 Roots.push_back(V); 288 return V; 289 } 290 291 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 292 ExplodedNode* addEndOfPath(ExplodedNode* V) { 293 EndNodes.push_back(V); 294 return V; 295 } 296 297 ExplodedGraph() 298 : NumNodes(0), recentlyAllocatedNodes(0), 299 freeNodes(0), reclaimNodes(false) {} 300 301 ~ExplodedGraph(); 302 303 unsigned num_roots() const { return Roots.size(); } 304 unsigned num_eops() const { return EndNodes.size(); } 305 306 bool empty() const { return NumNodes == 0; } 307 unsigned size() const { return NumNodes; } 308 309 // Iterators. 310 typedef ExplodedNode NodeTy; 311 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 312 typedef NodeTy** roots_iterator; 313 typedef NodeTy* const * const_roots_iterator; 314 typedef NodeTy** eop_iterator; 315 typedef NodeTy* const * const_eop_iterator; 316 typedef AllNodesTy::iterator node_iterator; 317 typedef AllNodesTy::const_iterator const_node_iterator; 318 319 node_iterator nodes_begin() { return Nodes.begin(); } 320 321 node_iterator nodes_end() { return Nodes.end(); } 322 323 const_node_iterator nodes_begin() const { return Nodes.begin(); } 324 325 const_node_iterator nodes_end() const { return Nodes.end(); } 326 327 roots_iterator roots_begin() { return Roots.begin(); } 328 329 roots_iterator roots_end() { return Roots.end(); } 330 331 const_roots_iterator roots_begin() const { return Roots.begin(); } 332 333 const_roots_iterator roots_end() const { return Roots.end(); } 334 335 eop_iterator eop_begin() { return EndNodes.begin(); } 336 337 eop_iterator eop_end() { return EndNodes.end(); } 338 339 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 340 341 const_eop_iterator eop_end() const { return EndNodes.end(); } 342 343 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 344 BumpVectorContext &getNodeAllocator() { return BVC; } 345 346 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 347 348 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 349 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 350 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 351 352 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 353 const ExplodedNode* const * NEnd, 354 InterExplodedGraphMap *M, 355 llvm::DenseMap<const void*, const void*> *InverseMap) const; 356 357 /// Enable tracking of recently allocated nodes for potential reclamation 358 /// when calling reclaimRecentlyAllocatedNodes(). 359 void enableNodeReclamation() { reclaimNodes = true; } 360 361 /// Reclaim "uninteresting" nodes created since the last time this method 362 /// was called. 363 void reclaimRecentlyAllocatedNodes(); 364 }; 365 366 class ExplodedNodeSet { 367 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 368 ImplTy Impl; 369 370 public: 371 ExplodedNodeSet(ExplodedNode* N) { 372 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 373 Impl.insert(N); 374 } 375 376 ExplodedNodeSet() {} 377 378 inline void Add(ExplodedNode* N) { 379 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 380 } 381 382 ExplodedNodeSet& operator=(const ExplodedNodeSet &X) { 383 Impl = X.Impl; 384 return *this; 385 } 386 387 typedef ImplTy::iterator iterator; 388 typedef ImplTy::const_iterator const_iterator; 389 390 unsigned size() const { return Impl.size(); } 391 bool empty() const { return Impl.empty(); } 392 393 void clear() { Impl.clear(); } 394 void insert(const ExplodedNodeSet &S) { 395 if (empty()) 396 Impl = S.Impl; 397 else 398 Impl.insert(S.begin(), S.end()); 399 } 400 401 inline iterator begin() { return Impl.begin(); } 402 inline iterator end() { return Impl.end(); } 403 404 inline const_iterator begin() const { return Impl.begin(); } 405 inline const_iterator end() const { return Impl.end(); } 406 }; 407 408 } // end GR namespace 409 410 } // end clang namespace 411 412 // GraphTraits 413 414 namespace llvm { 415 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 416 typedef clang::ento::ExplodedNode NodeType; 417 typedef NodeType::succ_iterator ChildIteratorType; 418 typedef llvm::df_iterator<NodeType*> nodes_iterator; 419 420 static inline NodeType* getEntryNode(NodeType* N) { 421 return N; 422 } 423 424 static inline ChildIteratorType child_begin(NodeType* N) { 425 return N->succ_begin(); 426 } 427 428 static inline ChildIteratorType child_end(NodeType* N) { 429 return N->succ_end(); 430 } 431 432 static inline nodes_iterator nodes_begin(NodeType* N) { 433 return df_begin(N); 434 } 435 436 static inline nodes_iterator nodes_end(NodeType* N) { 437 return df_end(N); 438 } 439 }; 440 441 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 442 typedef const clang::ento::ExplodedNode NodeType; 443 typedef NodeType::const_succ_iterator ChildIteratorType; 444 typedef llvm::df_iterator<NodeType*> nodes_iterator; 445 446 static inline NodeType* getEntryNode(NodeType* N) { 447 return N; 448 } 449 450 static inline ChildIteratorType child_begin(NodeType* N) { 451 return N->succ_begin(); 452 } 453 454 static inline ChildIteratorType child_end(NodeType* N) { 455 return N->succ_end(); 456 } 457 458 static inline nodes_iterator nodes_begin(NodeType* N) { 459 return df_begin(N); 460 } 461 462 static inline nodes_iterator nodes_end(NodeType* N) { 463 return df_end(N); 464 } 465 }; 466 467 } // end llvm namespace 468 469 #endif 470
