ExplodedGraph.h revision 99ba9e3bd70671f3441fb974895f226a83ce0e66
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 36namespace clang { 37 38class CFG; 39 40namespace ento { 41 42class 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 53class ExplodedNode : public llvm::FoldingSetNode { 54 friend class ExplodedGraph; 55 friend class CoreEngine; 56 friend class NodeBuilder; 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 ProgramState *State; 110 111 /// Preds - The predecessors of this node. 112 NodeGroup Preds; 113 114 /// Succs - The successors of this node. 115 NodeGroup Succs; 116 117public: 118 119 explicit ExplodedNode(const ProgramPoint &loc, const ProgramState *state, 120 bool IsSink) 121 : Location(loc), State(state) { 122 const_cast<ProgramState*>(State)->incrementReferenceCount(); 123 if (IsSink) 124 Succs.setFlag(); 125 } 126 127 ~ExplodedNode() { 128 const_cast<ProgramState*>(State)->decrementReferenceCount(); 129 } 130 131 /// getLocation - Returns the edge associated with the given node. 132 ProgramPoint getLocation() const { return Location; } 133 134 const LocationContext *getLocationContext() const { 135 return getLocation().getLocationContext(); 136 } 137 138 const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); } 139 140 CFG &getCFG() const { return *getLocationContext()->getCFG(); } 141 142 ParentMap &getParentMap() const {return getLocationContext()->getParentMap();} 143 144 template <typename T> 145 T &getAnalysis() const { 146 return *getLocationContext()->getAnalysis<T>(); 147 } 148 149 const ProgramState *getState() const { return State; } 150 151 template <typename T> 152 const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); } 153 154 static void Profile(llvm::FoldingSetNodeID &ID, 155 const ProgramPoint &Loc, 156 const ProgramState *state, 157 bool IsSink) { 158 ID.Add(Loc); 159 ID.AddPointer(state); 160 ID.AddBoolean(IsSink); 161 } 162 163 void Profile(llvm::FoldingSetNodeID& ID) const { 164 Profile(ID, getLocation(), getState(), isSink()); 165 } 166 167 /// addPredeccessor - Adds a predecessor to the current node, and 168 /// in tandem add this node as a successor of the other node. 169 void addPredecessor(ExplodedNode *V, ExplodedGraph &G); 170 171 unsigned succ_size() const { return Succs.size(); } 172 unsigned pred_size() const { return Preds.size(); } 173 bool succ_empty() const { return Succs.empty(); } 174 bool pred_empty() const { return Preds.empty(); } 175 176 bool isSink() const { return Succs.getFlag(); } 177 178 ExplodedNode *getFirstPred() { 179 return pred_empty() ? NULL : *(pred_begin()); 180 } 181 182 const ExplodedNode *getFirstPred() const { 183 return const_cast<ExplodedNode*>(this)->getFirstPred(); 184 } 185 186 // Iterators over successor and predecessor vertices. 187 typedef ExplodedNode** succ_iterator; 188 typedef const ExplodedNode* const * const_succ_iterator; 189 typedef ExplodedNode** pred_iterator; 190 typedef const ExplodedNode* const * const_pred_iterator; 191 192 pred_iterator pred_begin() { return Preds.begin(); } 193 pred_iterator pred_end() { return Preds.end(); } 194 195 const_pred_iterator pred_begin() const { 196 return const_cast<ExplodedNode*>(this)->pred_begin(); 197 } 198 const_pred_iterator pred_end() const { 199 return const_cast<ExplodedNode*>(this)->pred_end(); 200 } 201 202 succ_iterator succ_begin() { return Succs.begin(); } 203 succ_iterator succ_end() { return Succs.end(); } 204 205 const_succ_iterator succ_begin() const { 206 return const_cast<ExplodedNode*>(this)->succ_begin(); 207 } 208 const_succ_iterator succ_end() const { 209 return const_cast<ExplodedNode*>(this)->succ_end(); 210 } 211 212 // For debugging. 213 214public: 215 216 class Auditor { 217 public: 218 virtual ~Auditor(); 219 virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst) = 0; 220 }; 221 222 static void SetAuditor(Auditor* A); 223 224private: 225 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); } 226 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); } 227}; 228 229// FIXME: Is this class necessary? 230class InterExplodedGraphMap { 231 virtual void anchor(); 232 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M; 233 friend class ExplodedGraph; 234 235public: 236 ExplodedNode *getMappedNode(const ExplodedNode *N) const; 237 238 InterExplodedGraphMap() {} 239 virtual ~InterExplodedGraphMap() {} 240}; 241 242class ExplodedGraph { 243protected: 244 friend class CoreEngine; 245 246 // Type definitions. 247 typedef SmallVector<ExplodedNode*,2> RootsTy; 248 typedef SmallVector<ExplodedNode*,10> EndNodesTy; 249 250 /// Roots - The roots of the simulation graph. Usually there will be only 251 /// one, but clients are free to establish multiple subgraphs within a single 252 /// SimulGraph. Moreover, these subgraphs can often merge when paths from 253 /// different roots reach the same state at the same program location. 254 RootsTy Roots; 255 256 /// EndNodes - The nodes in the simulation graph which have been 257 /// specially marked as the endpoint of an abstract simulation path. 258 EndNodesTy EndNodes; 259 260 /// Nodes - The nodes in the graph. 261 llvm::FoldingSet<ExplodedNode> Nodes; 262 263 /// BVC - Allocator and context for allocating nodes and their predecessor 264 /// and successor groups. 265 BumpVectorContext BVC; 266 267 /// NumNodes - The number of nodes in the graph. 268 unsigned NumNodes; 269 270 /// A list of recently allocated nodes that can potentially be recycled. 271 void *recentlyAllocatedNodes; 272 273 /// A list of nodes that can be reused. 274 void *freeNodes; 275 276 /// A flag that indicates whether nodes should be recycled. 277 bool reclaimNodes; 278 279public: 280 281 /// \brief Retrieve the node associated with a (Location,State) pair, 282 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 283 /// this pair exists, it is created. IsNew is set to true if 284 /// the node was freshly created. 285 ExplodedNode *getNode(const ProgramPoint &L, const ProgramState *State, 286 bool IsSink = false, 287 bool* IsNew = 0); 288 289 ExplodedGraph* MakeEmptyGraph() const { 290 return new ExplodedGraph(); 291 } 292 293 /// addRoot - Add an untyped node to the set of roots. 294 ExplodedNode *addRoot(ExplodedNode *V) { 295 Roots.push_back(V); 296 return V; 297 } 298 299 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 300 ExplodedNode *addEndOfPath(ExplodedNode *V) { 301 EndNodes.push_back(V); 302 return V; 303 } 304 305 ExplodedGraph() 306 : NumNodes(0), recentlyAllocatedNodes(0), 307 freeNodes(0), reclaimNodes(false) {} 308 309 ~ExplodedGraph(); 310 311 unsigned num_roots() const { return Roots.size(); } 312 unsigned num_eops() const { return EndNodes.size(); } 313 314 bool empty() const { return NumNodes == 0; } 315 unsigned size() const { return NumNodes; } 316 317 // Iterators. 318 typedef ExplodedNode NodeTy; 319 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 320 typedef NodeTy** roots_iterator; 321 typedef NodeTy* const * const_roots_iterator; 322 typedef NodeTy** eop_iterator; 323 typedef NodeTy* const * const_eop_iterator; 324 typedef AllNodesTy::iterator node_iterator; 325 typedef AllNodesTy::const_iterator const_node_iterator; 326 327 node_iterator nodes_begin() { return Nodes.begin(); } 328 329 node_iterator nodes_end() { return Nodes.end(); } 330 331 const_node_iterator nodes_begin() const { return Nodes.begin(); } 332 333 const_node_iterator nodes_end() const { return Nodes.end(); } 334 335 roots_iterator roots_begin() { return Roots.begin(); } 336 337 roots_iterator roots_end() { return Roots.end(); } 338 339 const_roots_iterator roots_begin() const { return Roots.begin(); } 340 341 const_roots_iterator roots_end() const { return Roots.end(); } 342 343 eop_iterator eop_begin() { return EndNodes.begin(); } 344 345 eop_iterator eop_end() { return EndNodes.end(); } 346 347 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 348 349 const_eop_iterator eop_end() const { return EndNodes.end(); } 350 351 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 352 BumpVectorContext &getNodeAllocator() { return BVC; } 353 354 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 355 356 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 357 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 358 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 359 360 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 361 const ExplodedNode* const * NEnd, 362 InterExplodedGraphMap *M, 363 llvm::DenseMap<const void*, const void*> *InverseMap) const; 364 365 /// Enable tracking of recently allocated nodes for potential reclamation 366 /// when calling reclaimRecentlyAllocatedNodes(). 367 void enableNodeReclamation() { reclaimNodes = true; } 368 369 /// Reclaim "uninteresting" nodes created since the last time this method 370 /// was called. 371 void reclaimRecentlyAllocatedNodes(); 372}; 373 374class ExplodedNodeSet { 375 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 376 ImplTy Impl; 377 378public: 379 ExplodedNodeSet(ExplodedNode *N) { 380 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 381 Impl.insert(N); 382 } 383 384 ExplodedNodeSet() {} 385 386 inline void Add(ExplodedNode *N) { 387 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 388 } 389 390 typedef ImplTy::iterator iterator; 391 typedef ImplTy::const_iterator const_iterator; 392 393 unsigned size() const { return Impl.size(); } 394 bool empty() const { return Impl.empty(); } 395 bool erase(ExplodedNode *N) { return Impl.erase(N); } 396 397 void clear() { Impl.clear(); } 398 void insert(const ExplodedNodeSet &S) { 399 assert(&S != this); 400 if (empty()) 401 Impl = S.Impl; 402 else 403 Impl.insert(S.begin(), S.end()); 404 } 405 406 inline iterator begin() { return Impl.begin(); } 407 inline iterator end() { return Impl.end(); } 408 409 inline const_iterator begin() const { return Impl.begin(); } 410 inline const_iterator end() const { return Impl.end(); } 411}; 412 413} // end GR namespace 414 415} // end clang namespace 416 417// GraphTraits 418 419namespace llvm { 420 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 421 typedef clang::ento::ExplodedNode NodeType; 422 typedef NodeType::succ_iterator ChildIteratorType; 423 typedef llvm::df_iterator<NodeType*> nodes_iterator; 424 425 static inline NodeType* getEntryNode(NodeType* N) { 426 return N; 427 } 428 429 static inline ChildIteratorType child_begin(NodeType* N) { 430 return N->succ_begin(); 431 } 432 433 static inline ChildIteratorType child_end(NodeType* N) { 434 return N->succ_end(); 435 } 436 437 static inline nodes_iterator nodes_begin(NodeType* N) { 438 return df_begin(N); 439 } 440 441 static inline nodes_iterator nodes_end(NodeType* N) { 442 return df_end(N); 443 } 444 }; 445 446 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 447 typedef const clang::ento::ExplodedNode NodeType; 448 typedef NodeType::const_succ_iterator ChildIteratorType; 449 typedef llvm::df_iterator<NodeType*> nodes_iterator; 450 451 static inline NodeType* getEntryNode(NodeType* N) { 452 return N; 453 } 454 455 static inline ChildIteratorType child_begin(NodeType* N) { 456 return N->succ_begin(); 457 } 458 459 static inline ChildIteratorType child_end(NodeType* N) { 460 return N->succ_end(); 461 } 462 463 static inline nodes_iterator nodes_begin(NodeType* N) { 464 return df_begin(N); 465 } 466 467 static inline nodes_iterator nodes_end(NodeType* N) { 468 return df_end(N); 469 } 470 }; 471 472} // end llvm namespace 473 474#endif 475