ExplodedGraph.h revision 8bef8238181a30e52dea380789a7e2d760eac532
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 ProgramStateRef 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, ProgramStateRef 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 ProgramStateRef 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 ProgramStateRef 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; 278 279 /// Counter to determine when to reclaim nodes. 280 unsigned reclaimCounter; 281 282public: 283 284 /// \brief Retrieve the node associated with a (Location,State) pair, 285 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 286 /// this pair exists, it is created. IsNew is set to true if 287 /// the node was freshly created. 288 ExplodedNode *getNode(const ProgramPoint &L, ProgramStateRef State, 289 bool IsSink = false, 290 bool* IsNew = 0); 291 292 ExplodedGraph* MakeEmptyGraph() const { 293 return new ExplodedGraph(); 294 } 295 296 /// addRoot - Add an untyped node to the set of roots. 297 ExplodedNode *addRoot(ExplodedNode *V) { 298 Roots.push_back(V); 299 return V; 300 } 301 302 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 303 ExplodedNode *addEndOfPath(ExplodedNode *V) { 304 EndNodes.push_back(V); 305 return V; 306 } 307 308 ExplodedGraph(); 309 310 ~ExplodedGraph(); 311 312 unsigned num_roots() const { return Roots.size(); } 313 unsigned num_eops() const { return EndNodes.size(); } 314 315 bool empty() const { return NumNodes == 0; } 316 unsigned size() const { return NumNodes; } 317 318 // Iterators. 319 typedef ExplodedNode NodeTy; 320 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 321 typedef NodeTy** roots_iterator; 322 typedef NodeTy* const * const_roots_iterator; 323 typedef NodeTy** eop_iterator; 324 typedef NodeTy* const * const_eop_iterator; 325 typedef AllNodesTy::iterator node_iterator; 326 typedef AllNodesTy::const_iterator const_node_iterator; 327 328 node_iterator nodes_begin() { return Nodes.begin(); } 329 330 node_iterator nodes_end() { return Nodes.end(); } 331 332 const_node_iterator nodes_begin() const { return Nodes.begin(); } 333 334 const_node_iterator nodes_end() const { return Nodes.end(); } 335 336 roots_iterator roots_begin() { return Roots.begin(); } 337 338 roots_iterator roots_end() { return Roots.end(); } 339 340 const_roots_iterator roots_begin() const { return Roots.begin(); } 341 342 const_roots_iterator roots_end() const { return Roots.end(); } 343 344 eop_iterator eop_begin() { return EndNodes.begin(); } 345 346 eop_iterator eop_end() { return EndNodes.end(); } 347 348 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 349 350 const_eop_iterator eop_end() const { return EndNodes.end(); } 351 352 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 353 BumpVectorContext &getNodeAllocator() { return BVC; } 354 355 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 356 357 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 358 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 359 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 360 361 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 362 const ExplodedNode* const * NEnd, 363 InterExplodedGraphMap *M, 364 llvm::DenseMap<const void*, const void*> *InverseMap) const; 365 366 /// Enable tracking of recently allocated nodes for potential reclamation 367 /// when calling reclaimRecentlyAllocatedNodes(). 368 void enableNodeReclamation() { reclaimNodes = true; } 369 370 /// Reclaim "uninteresting" nodes created since the last time this method 371 /// was called. 372 void reclaimRecentlyAllocatedNodes(); 373}; 374 375class ExplodedNodeSet { 376 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 377 ImplTy Impl; 378 379public: 380 ExplodedNodeSet(ExplodedNode *N) { 381 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 382 Impl.insert(N); 383 } 384 385 ExplodedNodeSet() {} 386 387 inline void Add(ExplodedNode *N) { 388 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 389 } 390 391 typedef ImplTy::iterator iterator; 392 typedef ImplTy::const_iterator const_iterator; 393 394 unsigned size() const { return Impl.size(); } 395 bool empty() const { return Impl.empty(); } 396 bool erase(ExplodedNode *N) { return Impl.erase(N); } 397 398 void clear() { Impl.clear(); } 399 void insert(const ExplodedNodeSet &S) { 400 assert(&S != this); 401 if (empty()) 402 Impl = S.Impl; 403 else 404 Impl.insert(S.begin(), S.end()); 405 } 406 407 inline iterator begin() { return Impl.begin(); } 408 inline iterator end() { return Impl.end(); } 409 410 inline const_iterator begin() const { return Impl.begin(); } 411 inline const_iterator end() const { return Impl.end(); } 412}; 413 414} // end GR namespace 415 416} // end clang namespace 417 418// GraphTraits 419 420namespace llvm { 421 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 422 typedef clang::ento::ExplodedNode NodeType; 423 typedef NodeType::succ_iterator ChildIteratorType; 424 typedef llvm::df_iterator<NodeType*> nodes_iterator; 425 426 static inline NodeType* getEntryNode(NodeType* N) { 427 return N; 428 } 429 430 static inline ChildIteratorType child_begin(NodeType* N) { 431 return N->succ_begin(); 432 } 433 434 static inline ChildIteratorType child_end(NodeType* N) { 435 return N->succ_end(); 436 } 437 438 static inline nodes_iterator nodes_begin(NodeType* N) { 439 return df_begin(N); 440 } 441 442 static inline nodes_iterator nodes_end(NodeType* N) { 443 return df_end(N); 444 } 445 }; 446 447 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 448 typedef const clang::ento::ExplodedNode NodeType; 449 typedef NodeType::const_succ_iterator ChildIteratorType; 450 typedef llvm::df_iterator<NodeType*> nodes_iterator; 451 452 static inline NodeType* getEntryNode(NodeType* N) { 453 return N; 454 } 455 456 static inline ChildIteratorType child_begin(NodeType* N) { 457 return N->succ_begin(); 458 } 459 460 static inline ChildIteratorType child_end(NodeType* N) { 461 return N->succ_end(); 462 } 463 464 static inline nodes_iterator nodes_begin(NodeType* N) { 465 return df_begin(N); 466 } 467 468 static inline nodes_iterator nodes_end(NodeType* N) { 469 return df_end(N); 470 } 471 }; 472 473} // end llvm namespace 474 475#endif 476