1 //=-- ExplodedGraph.h - Local, Path-Sens. "Exploded Graph" -*- C++ -*-------==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_CLANG_GR_EXPLODEDGRAPH
20 #define LLVM_CLANG_GR_EXPLODEDGRAPH
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"
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 //===----------------------------------------------------------------------===//
51 // ExplodedNode is not constified all over the engine because we need to add
52 // successors to it at any time after creating it.
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;
64 enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 };
67 unsigned getKind() const {
71 void *getPtr() const {
73 return reinterpret_cast<void*>(P & ~Mask);
76 ExplodedNode *getNode() const {
77 return reinterpret_cast<ExplodedNode*>(getPtr());
83 ExplodedNode **begin() const;
85 ExplodedNode **end() const;
87 unsigned size() const;
89 bool empty() const { return (P & ~Mask) == 0; }
91 void addNode(ExplodedNode *N, ExplodedGraph &G);
93 void replaceNode(ExplodedNode *node);
100 bool getFlag() const {
101 return P & AuxFlag ? true : false;
105 /// Location - The program location (within a function body) associated
107 const ProgramPoint Location;
109 /// State - The state associated with this node.
110 ProgramStateRef State;
112 /// Preds - The predecessors of this node.
115 /// Succs - The successors of this node.
120 explicit ExplodedNode(const ProgramPoint &loc, ProgramStateRef state,
122 : Location(loc), State(state) {
129 /// getLocation - Returns the edge associated with the given node.
130 ProgramPoint getLocation() const { return Location; }
132 const LocationContext *getLocationContext() const {
133 return getLocation().getLocationContext();
136 const Decl &getCodeDecl() const { return *getLocationContext()->getDecl(); }
138 CFG &getCFG() const { return *getLocationContext()->getCFG(); }
140 ParentMap &getParentMap() const {return getLocationContext()->getParentMap();}
142 template <typename T>
143 T &getAnalysis() const {
144 return *getLocationContext()->getAnalysis<T>();
147 ProgramStateRef getState() const { return State; }
149 template <typename T>
150 const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); }
152 static void Profile(llvm::FoldingSetNodeID &ID,
153 const ProgramPoint &Loc,
154 ProgramStateRef state,
157 ID.AddPointer(state.getPtr());
158 ID.AddBoolean(IsSink);
161 void Profile(llvm::FoldingSetNodeID& ID) const {
162 Profile(ID, getLocation(), getState(), isSink());
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);
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(); }
174 bool isSink() const { return Succs.getFlag(); }
176 bool hasSinglePred() const {
177 return (pred_size() == 1);
180 ExplodedNode *getFirstPred() {
181 return pred_empty() ? NULL : *(pred_begin());
184 const ExplodedNode *getFirstPred() const {
185 return const_cast<ExplodedNode*>(this)->getFirstPred();
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;
194 pred_iterator pred_begin() { return Preds.begin(); }
195 pred_iterator pred_end() { return Preds.end(); }
197 const_pred_iterator pred_begin() const {
198 return const_cast<ExplodedNode*>(this)->pred_begin();
200 const_pred_iterator pred_end() const {
201 return const_cast<ExplodedNode*>(this)->pred_end();
204 succ_iterator succ_begin() { return Succs.begin(); }
205 succ_iterator succ_end() { return Succs.end(); }
207 const_succ_iterator succ_begin() const {
208 return const_cast<ExplodedNode*>(this)->succ_begin();
210 const_succ_iterator succ_end() const {
211 return const_cast<ExplodedNode*>(this)->succ_end();
221 virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst) = 0;
224 static void SetAuditor(Auditor* A);
227 void replaceSuccessor(ExplodedNode *node) { Succs.replaceNode(node); }
228 void replacePredecessor(ExplodedNode *node) { Preds.replaceNode(node); }
231 // FIXME: Is this class necessary?
232 class InterExplodedGraphMap {
233 virtual void anchor();
234 llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M;
235 friend class ExplodedGraph;
238 ExplodedNode *getMappedNode(const ExplodedNode *N) const;
240 InterExplodedGraphMap() {}
241 virtual ~InterExplodedGraphMap() {}
244 class ExplodedGraph {
246 friend class CoreEngine;
249 typedef std::vector<ExplodedNode *> NodeVector;
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.
257 /// The nodes in the simulation graph which have been
258 /// specially marked as the endpoint of an abstract simulation path.
261 /// Nodes - The nodes in the graph.
262 llvm::FoldingSet<ExplodedNode> Nodes;
264 /// BVC - Allocator and context for allocating nodes and their predecessor
265 /// and successor groups.
266 BumpVectorContext BVC;
268 /// NumNodes - The number of nodes in the graph.
271 /// A list of recently allocated nodes that can potentially be recycled.
272 NodeVector ChangedNodes;
274 /// A list of nodes that can be reused.
275 NodeVector FreeNodes;
277 /// A flag that indicates whether nodes should be recycled.
280 /// Counter to determine when to reclaim nodes.
281 unsigned reclaimCounter;
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,
293 ExplodedGraph* MakeEmptyGraph() const {
294 return new ExplodedGraph();
297 /// addRoot - Add an untyped node to the set of roots.
298 ExplodedNode *addRoot(ExplodedNode *V) {
303 /// addEndOfPath - Add an untyped node to the set of EOP nodes.
304 ExplodedNode *addEndOfPath(ExplodedNode *V) {
305 EndNodes.push_back(V);
313 unsigned num_roots() const { return Roots.size(); }
314 unsigned num_eops() const { return EndNodes.size(); }
316 bool empty() const { return NumNodes == 0; }
317 unsigned size() const { return NumNodes; }
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;
329 node_iterator nodes_begin() { return Nodes.begin(); }
331 node_iterator nodes_end() { return Nodes.end(); }
333 const_node_iterator nodes_begin() const { return Nodes.begin(); }
335 const_node_iterator nodes_end() const { return Nodes.end(); }
337 roots_iterator roots_begin() { return Roots.begin(); }
339 roots_iterator roots_end() { return Roots.end(); }
341 const_roots_iterator roots_begin() const { return Roots.begin(); }
343 const_roots_iterator roots_end() const { return Roots.end(); }
345 eop_iterator eop_begin() { return EndNodes.begin(); }
347 eop_iterator eop_end() { return EndNodes.end(); }
349 const_eop_iterator eop_begin() const { return EndNodes.begin(); }
351 const_eop_iterator eop_end() const { return EndNodes.end(); }
353 llvm::BumpPtrAllocator & getAllocator() { return BVC.getAllocator(); }
354 BumpVectorContext &getNodeAllocator() { return BVC; }
356 typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap;
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;
362 ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg,
363 const ExplodedNode* const * NEnd,
364 InterExplodedGraphMap *M,
365 llvm::DenseMap<const void*, const void*> *InverseMap) const;
367 /// Enable tracking of recently allocated nodes for potential reclamation
368 /// when calling reclaimRecentlyAllocatedNodes().
369 void enableNodeReclamation() { reclaimNodes = true; }
371 /// Reclaim "uninteresting" nodes created since the last time this method
373 void reclaimRecentlyAllocatedNodes();
376 bool shouldCollect(const ExplodedNode *node);
377 void collectNode(ExplodedNode *node);
380 class ExplodedNodeSet {
381 typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy;
385 ExplodedNodeSet(ExplodedNode *N) {
386 assert (N && !static_cast<ExplodedNode*>(N)->isSink());
392 inline void Add(ExplodedNode *N) {
393 if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N);
396 typedef ImplTy::iterator iterator;
397 typedef ImplTy::const_iterator const_iterator;
399 unsigned size() const { return Impl.size(); }
400 bool empty() const { return Impl.empty(); }
401 bool erase(ExplodedNode *N) { return Impl.erase(N); }
403 void clear() { Impl.clear(); }
404 void insert(const ExplodedNodeSet &S) {
409 Impl.insert(S.begin(), S.end());
412 inline iterator begin() { return Impl.begin(); }
413 inline iterator end() { return Impl.end(); }
415 inline const_iterator begin() const { return Impl.begin(); }
416 inline const_iterator end() const { return Impl.end(); }
419 } // end GR namespace
421 } // end clang namespace
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;
431 static inline NodeType* getEntryNode(NodeType* N) {
435 static inline ChildIteratorType child_begin(NodeType* N) {
436 return N->succ_begin();
439 static inline ChildIteratorType child_end(NodeType* N) {
440 return N->succ_end();
443 static inline nodes_iterator nodes_begin(NodeType* N) {
447 static inline nodes_iterator nodes_end(NodeType* N) {
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;
457 static inline NodeType* getEntryNode(NodeType* N) {
461 static inline ChildIteratorType child_begin(NodeType* N) {
462 return N->succ_begin();
465 static inline ChildIteratorType child_end(NodeType* N) {
466 return N->succ_end();
469 static inline nodes_iterator nodes_begin(NodeType* N) {
473 static inline nodes_iterator nodes_end(NodeType* N) {
478 } // end llvm namespace