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 #include <vector> 36 37 namespace clang { 38 39 class CFG; 40 41 namespace ento { 42 43 class ExplodedGraph; 44 45 //===----------------------------------------------------------------------===// 46 // ExplodedGraph "implementation" classes. These classes are not typed to 47 // contain a specific kind of state. Typed-specialized versions are defined 48 // on top of these classes. 49 //===----------------------------------------------------------------------===// 50 51 // ExplodedNode is not constified all over the engine because we need to add 52 // successors to it at any time after creating it. 53 54 class ExplodedNode : public llvm::FoldingSetNode { 55 friend class ExplodedGraph; 56 friend class CoreEngine; 57 friend class NodeBuilder; 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 ProgramStateRef 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, ProgramStateRef state, 121 bool IsSink) 122 : Location(loc), State(state) { 123 if (IsSink) 124 Succs.setFlag(); 125 } 126 127 ~ExplodedNode() {} 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 ProgramStateRef 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, 154 ProgramStateRef state, 155 bool IsSink) { 156 ID.Add(Loc); 157 ID.AddPointer(state.getPtr()); 158 ID.AddBoolean(IsSink); 159 } 160 161 void Profile(llvm::FoldingSetNodeID& ID) const { 162 Profile(ID, getLocation(), getState(), isSink()); 163 } 164 165 /// addPredeccessor - Adds a predecessor to the current node, and 166 /// in tandem add this node as a successor of the other node. 167 void addPredecessor(ExplodedNode *V, ExplodedGraph &G); 168 169 unsigned succ_size() const { return Succs.size(); } 170 unsigned pred_size() const { return Preds.size(); } 171 bool succ_empty() const { return Succs.empty(); } 172 bool pred_empty() const { return Preds.empty(); } 173 174 bool isSink() const { return Succs.getFlag(); } 175 176 bool hasSinglePred() const { 177 return (pred_size() == 1); 178 } 179 180 ExplodedNode *getFirstPred() { 181 return pred_empty() ? NULL : *(pred_begin()); 182 } 183 184 const ExplodedNode *getFirstPred() const { 185 return const_cast<ExplodedNode*>(this)->getFirstPred(); 186 } 187 188 // Iterators over successor and predecessor vertices. 189 typedef ExplodedNode** succ_iterator; 190 typedef const ExplodedNode* const * const_succ_iterator; 191 typedef ExplodedNode** pred_iterator; 192 typedef const ExplodedNode* const * const_pred_iterator; 193 194 pred_iterator pred_begin() { return Preds.begin(); } 195 pred_iterator pred_end() { return Preds.end(); } 196 197 const_pred_iterator pred_begin() const { 198 return const_cast<ExplodedNode*>(this)->pred_begin(); 199 } 200 const_pred_iterator pred_end() const { 201 return const_cast<ExplodedNode*>(this)->pred_end(); 202 } 203 204 succ_iterator succ_begin() { return Succs.begin(); } 205 succ_iterator succ_end() { return Succs.end(); } 206 207 const_succ_iterator succ_begin() const { 208 return const_cast<ExplodedNode*>(this)->succ_begin(); 209 } 210 const_succ_iterator succ_end() const { 211 return const_cast<ExplodedNode*>(this)->succ_end(); 212 } 213 214 // For debugging. 215 216 public: 217 218 class Auditor { 219 public: 220 virtual ~Auditor(); 221 virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst) = 0; 222 }; 223 224 static void SetAuditor(Auditor* A); 225 226 private: 227 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); } 228 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); } 229 }; 230 231 // FIXME: Is this class necessary? 232 class InterExplodedGraphMap { 233 virtual void anchor(); 234 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M; 235 friend class ExplodedGraph; 236 237 public: 238 ExplodedNode *getMappedNode(const ExplodedNode *N) const; 239 240 InterExplodedGraphMap() {} 241 virtual ~InterExplodedGraphMap() {} 242 }; 243 244 class ExplodedGraph { 245 protected: 246 friend class CoreEngine; 247 248 // Type definitions. 249 typedef std::vector<ExplodedNode *> NodeVector; 250 251 /// The roots of the simulation graph. Usually there will be only 252 /// one, but clients are free to establish multiple subgraphs within a single 253 /// SimulGraph. Moreover, these subgraphs can often merge when paths from 254 /// different roots reach the same state at the same program location. 255 NodeVector Roots; 256 257 /// The nodes in the simulation graph which have been 258 /// specially marked as the endpoint of an abstract simulation path. 259 NodeVector EndNodes; 260 261 /// Nodes - The nodes in the graph. 262 llvm::FoldingSet<ExplodedNode> Nodes; 263 264 /// BVC - Allocator and context for allocating nodes and their predecessor 265 /// and successor groups. 266 BumpVectorContext BVC; 267 268 /// NumNodes - The number of nodes in the graph. 269 unsigned NumNodes; 270 271 /// A list of recently allocated nodes that can potentially be recycled. 272 NodeVector ChangedNodes; 273 274 /// A list of nodes that can be reused. 275 NodeVector FreeNodes; 276 277 /// A flag that indicates whether nodes should be recycled. 278 bool reclaimNodes; 279 280 /// Counter to determine when to reclaim nodes. 281 unsigned reclaimCounter; 282 283 public: 284 285 /// \brief Retrieve the node associated with a (Location,State) pair, 286 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 287 /// this pair exists, it is created. IsNew is set to true if 288 /// the node was freshly created. 289 ExplodedNode *getNode(const ProgramPoint &L, ProgramStateRef State, 290 bool IsSink = false, 291 bool* IsNew = 0); 292 293 ExplodedGraph* MakeEmptyGraph() const { 294 return new ExplodedGraph(); 295 } 296 297 /// addRoot - Add an untyped node to the set of roots. 298 ExplodedNode *addRoot(ExplodedNode *V) { 299 Roots.push_back(V); 300 return V; 301 } 302 303 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 304 ExplodedNode *addEndOfPath(ExplodedNode *V) { 305 EndNodes.push_back(V); 306 return V; 307 } 308 309 ExplodedGraph(); 310 311 ~ExplodedGraph(); 312 313 unsigned num_roots() const { return Roots.size(); } 314 unsigned num_eops() const { return EndNodes.size(); } 315 316 bool empty() const { return NumNodes == 0; } 317 unsigned size() const { return NumNodes; } 318 319 // Iterators. 320 typedef ExplodedNode NodeTy; 321 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 322 typedef NodeVector::iterator roots_iterator; 323 typedef NodeVector::const_iterator const_roots_iterator; 324 typedef NodeVector::iterator eop_iterator; 325 typedef NodeVector::const_iterator const_eop_iterator; 326 typedef AllNodesTy::iterator node_iterator; 327 typedef AllNodesTy::const_iterator const_node_iterator; 328 329 node_iterator nodes_begin() { return Nodes.begin(); } 330 331 node_iterator nodes_end() { return Nodes.end(); } 332 333 const_node_iterator nodes_begin() const { return Nodes.begin(); } 334 335 const_node_iterator nodes_end() const { return Nodes.end(); } 336 337 roots_iterator roots_begin() { return Roots.begin(); } 338 339 roots_iterator roots_end() { return Roots.end(); } 340 341 const_roots_iterator roots_begin() const { return Roots.begin(); } 342 343 const_roots_iterator roots_end() const { return Roots.end(); } 344 345 eop_iterator eop_begin() { return EndNodes.begin(); } 346 347 eop_iterator eop_end() { return EndNodes.end(); } 348 349 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 350 351 const_eop_iterator eop_end() const { return EndNodes.end(); } 352 353 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 354 BumpVectorContext &getNodeAllocator() { return BVC; } 355 356 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 357 358 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 359 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 360 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 361 362 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 363 const ExplodedNode* const * NEnd, 364 InterExplodedGraphMap *M, 365 llvm::DenseMap<const void*, const void*> *InverseMap) const; 366 367 /// Enable tracking of recently allocated nodes for potential reclamation 368 /// when calling reclaimRecentlyAllocatedNodes(). 369 void enableNodeReclamation() { reclaimNodes = true; } 370 371 /// Reclaim "uninteresting" nodes created since the last time this method 372 /// was called. 373 void reclaimRecentlyAllocatedNodes(); 374 375 private: 376 bool shouldCollect(const ExplodedNode *node); 377 void collectNode(ExplodedNode *node); 378 }; 379 380 class ExplodedNodeSet { 381 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 382 ImplTy Impl; 383 384 public: 385 ExplodedNodeSet(ExplodedNode *N) { 386 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 387 Impl.insert(N); 388 } 389 390 ExplodedNodeSet() {} 391 392 inline void Add(ExplodedNode *N) { 393 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 394 } 395 396 typedef ImplTy::iterator iterator; 397 typedef ImplTy::const_iterator const_iterator; 398 399 unsigned size() const { return Impl.size(); } 400 bool empty() const { return Impl.empty(); } 401 bool erase(ExplodedNode *N) { return Impl.erase(N); } 402 403 void clear() { Impl.clear(); } 404 void insert(const ExplodedNodeSet &S) { 405 assert(&S != this); 406 if (empty()) 407 Impl = S.Impl; 408 else 409 Impl.insert(S.begin(), S.end()); 410 } 411 412 inline iterator begin() { return Impl.begin(); } 413 inline iterator end() { return Impl.end(); } 414 415 inline const_iterator begin() const { return Impl.begin(); } 416 inline const_iterator end() const { return Impl.end(); } 417 }; 418 419 } // end GR namespace 420 421 } // end clang namespace 422 423 // GraphTraits 424 425 namespace llvm { 426 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 427 typedef clang::ento::ExplodedNode NodeType; 428 typedef NodeType::succ_iterator ChildIteratorType; 429 typedef llvm::df_iterator<NodeType*> nodes_iterator; 430 431 static inline NodeType* getEntryNode(NodeType* N) { 432 return N; 433 } 434 435 static inline ChildIteratorType child_begin(NodeType* N) { 436 return N->succ_begin(); 437 } 438 439 static inline ChildIteratorType child_end(NodeType* N) { 440 return N->succ_end(); 441 } 442 443 static inline nodes_iterator nodes_begin(NodeType* N) { 444 return df_begin(N); 445 } 446 447 static inline nodes_iterator nodes_end(NodeType* N) { 448 return df_end(N); 449 } 450 }; 451 452 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 453 typedef const clang::ento::ExplodedNode NodeType; 454 typedef NodeType::const_succ_iterator ChildIteratorType; 455 typedef llvm::df_iterator<NodeType*> nodes_iterator; 456 457 static inline NodeType* getEntryNode(NodeType* N) { 458 return N; 459 } 460 461 static inline ChildIteratorType child_begin(NodeType* N) { 462 return N->succ_begin(); 463 } 464 465 static inline ChildIteratorType child_end(NodeType* N) { 466 return N->succ_end(); 467 } 468 469 static inline nodes_iterator nodes_begin(NodeType* N) { 470 return df_begin(N); 471 } 472 473 static inline nodes_iterator nodes_end(NodeType* N) { 474 return df_end(N); 475 } 476 }; 477 478 } // end llvm namespace 479 480 #endif 481
