ExplodedGraph.h revision 955cd444f445bcdbade1cdd3926254c8ee7890d8
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 37namespace clang { 38 39class CFG; 40 41namespace ento { 42 43class 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 54class 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 118public: 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 StackFrameContext *getStackFrame() const { 137 return getLocationContext()->getCurrentStackFrame(); 138 } 139 140 const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); } 141 142 CFG &getCFG() const { return *getLocationContext()->getCFG(); } 143 144 ParentMap &getParentMap() const {return getLocationContext()->getParentMap();} 145 146 template <typename T> 147 T &getAnalysis() const { 148 return *getLocationContext()->getAnalysis<T>(); 149 } 150 151 ProgramStateRef getState() const { return State; } 152 153 template <typename T> 154 const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); } 155 156 static void Profile(llvm::FoldingSetNodeID &ID, 157 const ProgramPoint &Loc, 158 const ProgramStateRef &state, 159 bool IsSink) { 160 ID.Add(Loc); 161 ID.AddPointer(state.getPtr()); 162 ID.AddBoolean(IsSink); 163 } 164 165 void Profile(llvm::FoldingSetNodeID& ID) const { 166 Profile(ID, getLocation(), getState(), isSink()); 167 } 168 169 /// addPredeccessor - Adds a predecessor to the current node, and 170 /// in tandem add this node as a successor of the other node. 171 void addPredecessor(ExplodedNode *V, ExplodedGraph &G); 172 173 unsigned succ_size() const { return Succs.size(); } 174 unsigned pred_size() const { return Preds.size(); } 175 bool succ_empty() const { return Succs.empty(); } 176 bool pred_empty() const { return Preds.empty(); } 177 178 bool isSink() const { return Succs.getFlag(); } 179 180 bool hasSinglePred() const { 181 return (pred_size() == 1); 182 } 183 184 ExplodedNode *getFirstPred() { 185 return pred_empty() ? NULL : *(pred_begin()); 186 } 187 188 const ExplodedNode *getFirstPred() const { 189 return const_cast<ExplodedNode*>(this)->getFirstPred(); 190 } 191 192 // Iterators over successor and predecessor vertices. 193 typedef ExplodedNode** succ_iterator; 194 typedef const ExplodedNode* const * const_succ_iterator; 195 typedef ExplodedNode** pred_iterator; 196 typedef const ExplodedNode* const * const_pred_iterator; 197 198 pred_iterator pred_begin() { return Preds.begin(); } 199 pred_iterator pred_end() { return Preds.end(); } 200 201 const_pred_iterator pred_begin() const { 202 return const_cast<ExplodedNode*>(this)->pred_begin(); 203 } 204 const_pred_iterator pred_end() const { 205 return const_cast<ExplodedNode*>(this)->pred_end(); 206 } 207 208 succ_iterator succ_begin() { return Succs.begin(); } 209 succ_iterator succ_end() { return Succs.end(); } 210 211 const_succ_iterator succ_begin() const { 212 return const_cast<ExplodedNode*>(this)->succ_begin(); 213 } 214 const_succ_iterator succ_end() const { 215 return const_cast<ExplodedNode*>(this)->succ_end(); 216 } 217 218 // For debugging. 219 220public: 221 222 class Auditor { 223 public: 224 virtual ~Auditor(); 225 virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst) = 0; 226 }; 227 228 static void SetAuditor(Auditor* A); 229 230private: 231 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); } 232 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); } 233}; 234 235// FIXME: Is this class necessary? 236class InterExplodedGraphMap { 237 virtual void anchor(); 238 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M; 239 friend class ExplodedGraph; 240 241public: 242 ExplodedNode *getMappedNode(const ExplodedNode *N) const; 243 244 InterExplodedGraphMap() {} 245 virtual ~InterExplodedGraphMap() {} 246}; 247 248class ExplodedGraph { 249protected: 250 friend class CoreEngine; 251 252 // Type definitions. 253 typedef std::vector<ExplodedNode *> NodeVector; 254 255 /// The roots of the simulation graph. Usually there will be only 256 /// one, but clients are free to establish multiple subgraphs within a single 257 /// SimulGraph. Moreover, these subgraphs can often merge when paths from 258 /// different roots reach the same state at the same program location. 259 NodeVector Roots; 260 261 /// The nodes in the simulation graph which have been 262 /// specially marked as the endpoint of an abstract simulation path. 263 NodeVector EndNodes; 264 265 /// Nodes - The nodes in the graph. 266 llvm::FoldingSet<ExplodedNode> Nodes; 267 268 /// BVC - Allocator and context for allocating nodes and their predecessor 269 /// and successor groups. 270 BumpVectorContext BVC; 271 272 /// NumNodes - The number of nodes in the graph. 273 unsigned NumNodes; 274 275 /// A list of recently allocated nodes that can potentially be recycled. 276 NodeVector ChangedNodes; 277 278 /// A list of nodes that can be reused. 279 NodeVector FreeNodes; 280 281 /// A flag that indicates whether nodes should be recycled. 282 bool reclaimNodes; 283 284 /// Counter to determine when to reclaim nodes. 285 unsigned reclaimCounter; 286 287public: 288 289 /// \brief Retrieve the node associated with a (Location,State) pair, 290 /// where the 'Location' is a ProgramPoint in the CFG. If no node for 291 /// this pair exists, it is created. IsNew is set to true if 292 /// the node was freshly created. 293 ExplodedNode *getNode(const ProgramPoint &L, ProgramStateRef State, 294 bool IsSink = false, 295 bool* IsNew = 0); 296 297 ExplodedGraph* MakeEmptyGraph() const { 298 return new ExplodedGraph(); 299 } 300 301 /// addRoot - Add an untyped node to the set of roots. 302 ExplodedNode *addRoot(ExplodedNode *V) { 303 Roots.push_back(V); 304 return V; 305 } 306 307 /// addEndOfPath - Add an untyped node to the set of EOP nodes. 308 ExplodedNode *addEndOfPath(ExplodedNode *V) { 309 EndNodes.push_back(V); 310 return V; 311 } 312 313 ExplodedGraph(); 314 315 ~ExplodedGraph(); 316 317 unsigned num_roots() const { return Roots.size(); } 318 unsigned num_eops() const { return EndNodes.size(); } 319 320 bool empty() const { return NumNodes == 0; } 321 unsigned size() const { return NumNodes; } 322 323 // Iterators. 324 typedef ExplodedNode NodeTy; 325 typedef llvm::FoldingSet<ExplodedNode> AllNodesTy; 326 typedef NodeVector::iterator roots_iterator; 327 typedef NodeVector::const_iterator const_roots_iterator; 328 typedef NodeVector::iterator eop_iterator; 329 typedef NodeVector::const_iterator const_eop_iterator; 330 typedef AllNodesTy::iterator node_iterator; 331 typedef AllNodesTy::const_iterator const_node_iterator; 332 333 node_iterator nodes_begin() { return Nodes.begin(); } 334 335 node_iterator nodes_end() { return Nodes.end(); } 336 337 const_node_iterator nodes_begin() const { return Nodes.begin(); } 338 339 const_node_iterator nodes_end() const { return Nodes.end(); } 340 341 roots_iterator roots_begin() { return Roots.begin(); } 342 343 roots_iterator roots_end() { return Roots.end(); } 344 345 const_roots_iterator roots_begin() const { return Roots.begin(); } 346 347 const_roots_iterator roots_end() const { return Roots.end(); } 348 349 eop_iterator eop_begin() { return EndNodes.begin(); } 350 351 eop_iterator eop_end() { return EndNodes.end(); } 352 353 const_eop_iterator eop_begin() const { return EndNodes.begin(); } 354 355 const_eop_iterator eop_end() const { return EndNodes.end(); } 356 357 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); } 358 BumpVectorContext &getNodeAllocator() { return BVC; } 359 360 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap; 361 362 std::pair<ExplodedGraph*, InterExplodedGraphMap*> 363 Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd, 364 llvm::DenseMap<const void*, const void*> *InverseMap = 0) const; 365 366 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg, 367 const ExplodedNode* const * NEnd, 368 InterExplodedGraphMap *M, 369 llvm::DenseMap<const void*, const void*> *InverseMap) const; 370 371 /// Enable tracking of recently allocated nodes for potential reclamation 372 /// when calling reclaimRecentlyAllocatedNodes(). 373 void enableNodeReclamation() { reclaimNodes = true; } 374 375 /// Reclaim "uninteresting" nodes created since the last time this method 376 /// was called. 377 void reclaimRecentlyAllocatedNodes(); 378 379private: 380 bool shouldCollect(const ExplodedNode *node); 381 void collectNode(ExplodedNode *node); 382}; 383 384class ExplodedNodeSet { 385 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy; 386 ImplTy Impl; 387 388public: 389 ExplodedNodeSet(ExplodedNode *N) { 390 assert (N && !static_cast<ExplodedNode*>(N)->isSink()); 391 Impl.insert(N); 392 } 393 394 ExplodedNodeSet() {} 395 396 inline void Add(ExplodedNode *N) { 397 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N); 398 } 399 400 typedef ImplTy::iterator iterator; 401 typedef ImplTy::const_iterator const_iterator; 402 403 unsigned size() const { return Impl.size(); } 404 bool empty() const { return Impl.empty(); } 405 bool erase(ExplodedNode *N) { return Impl.erase(N); } 406 407 void clear() { Impl.clear(); } 408 void insert(const ExplodedNodeSet &S) { 409 assert(&S != this); 410 if (empty()) 411 Impl = S.Impl; 412 else 413 Impl.insert(S.begin(), S.end()); 414 } 415 416 inline iterator begin() { return Impl.begin(); } 417 inline iterator end() { return Impl.end(); } 418 419 inline const_iterator begin() const { return Impl.begin(); } 420 inline const_iterator end() const { return Impl.end(); } 421}; 422 423} // end GR namespace 424 425} // end clang namespace 426 427// GraphTraits 428 429namespace llvm { 430 template<> struct GraphTraits<clang::ento::ExplodedNode*> { 431 typedef clang::ento::ExplodedNode NodeType; 432 typedef NodeType::succ_iterator ChildIteratorType; 433 typedef llvm::df_iterator<NodeType*> nodes_iterator; 434 435 static inline NodeType* getEntryNode(NodeType* N) { 436 return N; 437 } 438 439 static inline ChildIteratorType child_begin(NodeType* N) { 440 return N->succ_begin(); 441 } 442 443 static inline ChildIteratorType child_end(NodeType* N) { 444 return N->succ_end(); 445 } 446 447 static inline nodes_iterator nodes_begin(NodeType* N) { 448 return df_begin(N); 449 } 450 451 static inline nodes_iterator nodes_end(NodeType* N) { 452 return df_end(N); 453 } 454 }; 455 456 template<> struct GraphTraits<const clang::ento::ExplodedNode*> { 457 typedef const clang::ento::ExplodedNode NodeType; 458 typedef NodeType::const_succ_iterator ChildIteratorType; 459 typedef llvm::df_iterator<NodeType*> nodes_iterator; 460 461 static inline NodeType* getEntryNode(NodeType* N) { 462 return N; 463 } 464 465 static inline ChildIteratorType child_begin(NodeType* N) { 466 return N->succ_begin(); 467 } 468 469 static inline ChildIteratorType child_end(NodeType* N) { 470 return N->succ_end(); 471 } 472 473 static inline nodes_iterator nodes_begin(NodeType* N) { 474 return df_begin(N); 475 } 476 477 static inline nodes_iterator nodes_end(NodeType* N) { 478 return df_end(N); 479 } 480 }; 481 482} // end llvm namespace 483 484#endif 485