ExplodedGraph.h revision 11062b118476368fa5b294954713e5df97d8599f 
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//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_ANALYSIS_EXPLODEDGRAPH
16#define LLVM_CLANG_ANALYSIS_EXPLODEDGRAPH
17
18#include "clang/Analysis/ProgramPoint.h"
19#include "clang/AST/Decl.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/FoldingSet.h"
22#include "llvm/ADT/SmallPtrSet.h"
23#include "llvm/Support/Allocator.h"
24#include "llvm/ADT/OwningPtr.h"
25#include "llvm/ADT/GraphTraits.h"
26#include "llvm/ADT/DepthFirstIterator.h"
27#include "llvm/Support/Casting.h"
28
29namespace clang {
30
31class GRCoreEngineImpl;
32class ExplodedNodeImpl;
33class CFG;
34class ASTContext;
35
36class GRStmtNodeBuilderImpl;
37class GRBranchNodeBuilderImpl;
38class GRIndirectGotoNodeBuilderImpl;
39class GRSwitchNodeBuilderImpl;
40class GREndPathNodebuilderImpl;
41
42class ExplodedNodeImpl : public llvm::FoldingSetNode {
43protected:
44  friend class ExplodedGraphImpl;
45  friend class GRCoreEngineImpl;
46  friend class GRStmtNodeBuilderImpl;
47  friend class GRBranchNodeBuilderImpl;
48  friend class GRIndirectGotoNodeBuilderImpl;
49  friend class GRSwitchNodeBuilderImpl;
50  friend class GREndPathNodeBuilderImpl;
51
52  class NodeGroup {
53    enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 };
54    uintptr_t P;
55
56    unsigned getKind() const {
57      return P & 0x1;
58    }
59
60    void* getPtr() const {
61      assert (!getFlag());
62      return reinterpret_cast<void*>(P & ~Mask);
63    }
64
65    ExplodedNodeImpl* getNode() const {
66      return reinterpret_cast<ExplodedNodeImpl*>(getPtr());
67    }
68
69  public:
70    NodeGroup() : P(0) {}
71
72    ~NodeGroup();
73
74    ExplodedNodeImpl** begin() const;
75
76    ExplodedNodeImpl** end() const;
77
78    unsigned size() const;
79
80    bool empty() const { return size() == 0; }
81
82    void addNode(ExplodedNodeImpl* N);
83
84    void setFlag() {
85      assert (P == 0);
86      P = AuxFlag;
87    }
88
89    bool getFlag() const {
90      return P & AuxFlag ? true : false;
91    }
92  };
93
94  /// Location - The program location (within a function body) associated
95  ///  with this node.
96  const ProgramPoint Location;
97
98  /// State - The state associated with this node. Normally this value
99  ///  is immutable, but we anticipate there will be times when algorithms
100  ///  that directly manipulate the analysis graph will need to change it.
101  void* State;
102
103  /// Preds - The predecessors of this node.
104  NodeGroup Preds;
105
106  /// Succs - The successors of this node.
107  NodeGroup Succs;
108
109  /// Construct a ExplodedNodeImpl with the provided location and state.
110  explicit ExplodedNodeImpl(const ProgramPoint& loc, void* state)
111  : Location(loc), State(state) {}
112
113  /// addPredeccessor - Adds a predecessor to the current node, and
114  ///  in tandem add this node as a successor of the other node.
115  void addPredecessor(ExplodedNodeImpl* V) {
116    assert (!V->isSink());
117    Preds.addNode(V);
118    V->Succs.addNode(this);
119  }
120
121public:
122
123  /// getLocation - Returns the edge associated with the given node.
124  ProgramPoint getLocation() const { return Location; }
125
126  unsigned succ_size() const { return Succs.size(); }
127  unsigned pred_size() const { return Preds.size(); }
128  bool succ_empty() const { return Succs.empty(); }
129  bool pred_empty() const { return Preds.empty(); }
130
131  bool isSink() const { return Succs.getFlag(); }
132  void markAsSink() { Succs.setFlag(); }
133};
134
135
136template <typename StateTy>
137struct GRTrait {
138  static inline void Profile(llvm::FoldingSetNodeID& ID, const StateTy* St) {
139    St->Profile(ID);
140  }
141};
142
143
144template <typename StateTy>
145class ExplodedNode : public ExplodedNodeImpl {
146public:
147  /// Construct a ExplodedNodeImpl with the given node ID, program edge,
148  ///  and state.
149  explicit ExplodedNode(const ProgramPoint& loc, StateTy* St)
150    : ExplodedNodeImpl(loc, St) {}
151
152  /// getState - Returns the state associated with the node.
153  inline StateTy* getState() const {
154    return static_cast<StateTy*>(State);
155  }
156
157  // Profiling (for FoldingSet).
158
159  static inline void Profile(llvm::FoldingSetNodeID& ID,
160                             const ProgramPoint& Loc,
161                             StateTy* state) {
162    ID.Add(Loc);
163    GRTrait<StateTy>::Profile(ID, state);
164  }
165
166  inline void Profile(llvm::FoldingSetNodeID& ID) const {
167    Profile(ID, getLocation(), getState());
168  }
169
170  // Iterators over successor and predecessor vertices.
171  typedef ExplodedNode**       succ_iterator;
172  typedef const ExplodedNode** const_succ_iterator;
173  typedef ExplodedNode**       pred_iterator;
174  typedef const ExplodedNode** const_pred_iterator;
175
176  pred_iterator pred_begin() { return (ExplodedNode**) Preds.begin(); }
177  pred_iterator pred_end() { return (ExplodedNode**) Preds.end(); }
178
179  const_pred_iterator pred_begin() const {
180    return const_cast<ExplodedNode*>(this)->pred_begin();
181  }
182  const_pred_iterator pred_end() const {
183    return const_cast<ExplodedNode*>(this)->pred_end();
184  }
185
186  succ_iterator succ_begin() { return (ExplodedNode**) Succs.begin(); }
187  succ_iterator succ_end() { return (ExplodedNode**) Succs.end(); }
188
189  const_succ_iterator succ_begin() const {
190    return const_cast<ExplodedNode*>(this)->succ_begin();
191  }
192  const_succ_iterator succ_end() const {
193    return const_cast<ExplodedNode*>(this)->succ_end();
194  }
195};
196
197
198class ExplodedGraphImpl {
199protected:
200  friend class GRCoreEngineImpl;
201  friend class GRStmtNodeBuilderImpl;
202  friend class GRBranchNodeBuilderImpl;
203  friend class GRIndirectGotoNodeBuilderImpl;
204  friend class GRSwitchNodeBuilderImpl;
205  friend class GREndPathNodeBuilderImpl;
206
207  // Type definitions.
208  typedef llvm::SmallVector<ExplodedNodeImpl*,2>    RootsTy;
209  typedef llvm::SmallVector<ExplodedNodeImpl*,10>   EndNodesTy;
210
211  /// Roots - The roots of the simulation graph. Usually there will be only
212  /// one, but clients are free to establish multiple subgraphs within a single
213  /// SimulGraph. Moreover, these subgraphs can often merge when paths from
214  /// different roots reach the same state at the same program location.
215  RootsTy Roots;
216
217  /// EndNodes - The nodes in the simulation graph which have been
218  ///  specially marked as the endpoint of an abstract simulation path.
219  EndNodesTy EndNodes;
220
221  /// Allocator - BumpPtrAllocator to create nodes.
222  llvm::BumpPtrAllocator Allocator;
223
224  /// cfg - The CFG associated with this analysis graph.
225  CFG& cfg;
226
227  /// CodeDecl - The declaration containing the code being analyzed.  This
228  ///  can be a FunctionDecl or and ObjCMethodDecl.
229  Decl& CodeDecl;
230
231  /// Ctx - The ASTContext used to "interpret" CodeDecl.
232  ASTContext& Ctx;
233
234  /// NumNodes - The number of nodes in the graph.
235  unsigned NumNodes;
236
237  /// getNodeImpl - Retrieve the node associated with a (Location,State)
238  ///  pair, where 'State' is represented as an opaque void*.  This method
239  ///  is intended to be used only by GRCoreEngineImpl.
240  virtual ExplodedNodeImpl* getNodeImpl(const ProgramPoint& L, void* State,
241                                        bool* IsNew) = 0;
242
243  virtual ExplodedGraphImpl* MakeEmptyGraph() const = 0;
244
245  /// addRoot - Add an untyped node to the set of roots.
246  ExplodedNodeImpl* addRoot(ExplodedNodeImpl* V) {
247    Roots.push_back(V);
248    return V;
249  }
250
251  /// addEndOfPath - Add an untyped node to the set of EOP nodes.
252  ExplodedNodeImpl* addEndOfPath(ExplodedNodeImpl* V) {
253    EndNodes.push_back(V);
254    return V;
255  }
256
257  // ctor.
258  ExplodedGraphImpl(CFG& c, Decl& cd, ASTContext& ctx)
259    : cfg(c), CodeDecl(cd), Ctx(ctx), NumNodes(0) {}
260
261public:
262  virtual ~ExplodedGraphImpl() {}
263
264  unsigned num_roots() const { return Roots.size(); }
265  unsigned num_eops() const { return EndNodes.size(); }
266
267  bool empty() const { return NumNodes == 0; }
268  unsigned size() const { return NumNodes; }
269
270  llvm::BumpPtrAllocator& getAllocator() { return Allocator; }
271  CFG& getCFG() { return cfg; }
272  ASTContext& getContext() { return Ctx; }
273
274  const Decl& getCodeDecl() const { return CodeDecl; }
275
276  const FunctionDecl* getFunctionDecl() const {
277    return llvm::dyn_cast<FunctionDecl>(&CodeDecl);
278  }
279
280  ExplodedGraphImpl* Trim(ExplodedNodeImpl** NBeg,
281                          ExplodedNodeImpl** NEnd) const;
282
283};
284
285template <typename STATE>
286class ExplodedGraph : public ExplodedGraphImpl {
287public:
288  typedef STATE                       StateTy;
289  typedef ExplodedNode<StateTy>       NodeTy;
290  typedef llvm::FoldingSet<NodeTy>    AllNodesTy;
291
292protected:
293  /// Nodes - The nodes in the graph.
294  AllNodesTy Nodes;
295
296protected:
297  virtual ExplodedNodeImpl* getNodeImpl(const ProgramPoint& L,
298                                        void* State, bool* IsNew) {
299
300    return getNode(L, static_cast<StateTy*>(State), IsNew);
301  }
302
303  virtual ExplodedGraphImpl* MakeEmptyGraph() const {
304    return new ExplodedGraph(cfg, CodeDecl, Ctx);
305  }
306
307public:
308  ExplodedGraph(CFG& c, Decl& cd, ASTContext& ctx)
309    : ExplodedGraphImpl(c, cd, ctx) {}
310
311  /// getNode - Retrieve the node associated with a (Location,State) pair,
312  ///  where the 'Location' is a ProgramPoint in the CFG.  If no node for
313  ///  this pair exists, it is created.  IsNew is set to true if
314  ///  the node was freshly created.
315  NodeTy* getNode(const ProgramPoint& L, StateTy* State, bool* IsNew = NULL) {
316
317    // Profile 'State' to determine if we already have an existing node.
318    llvm::FoldingSetNodeID profile;
319    void* InsertPos = 0;
320
321    NodeTy::Profile(profile, L, State);
322    NodeTy* V = Nodes.FindNodeOrInsertPos(profile, InsertPos);
323
324    if (!V) {
325      // Allocate a new node.
326      V = (NodeTy*) Allocator.Allocate<NodeTy>();
327      new (V) NodeTy(L, State);
328
329      // Insert the node into the node set and return it.
330      Nodes.InsertNode(V, InsertPos);
331
332      ++NumNodes;
333
334      if (IsNew) *IsNew = true;
335    }
336    else
337      if (IsNew) *IsNew = false;
338
339    return V;
340  }
341
342  // Iterators.
343  typedef NodeTy**                            roots_iterator;
344  typedef const NodeTy**                      const_roots_iterator;
345  typedef NodeTy**                            eop_iterator;
346  typedef const NodeTy**                      const_eop_iterator;
347  typedef typename AllNodesTy::iterator       node_iterator;
348  typedef typename AllNodesTy::const_iterator const_node_iterator;
349
350  node_iterator nodes_begin() {
351    return Nodes.begin();
352  }
353
354  node_iterator nodes_end() {
355    return Nodes.end();
356  }
357
358  const_node_iterator nodes_begin() const {
359    return Nodes.begin();
360  }
361
362  const_node_iterator nodes_end() const {
363    return Nodes.end();
364  }
365
366  roots_iterator roots_begin() {
367    return reinterpret_cast<roots_iterator>(Roots.begin());
368  }
369
370  roots_iterator roots_end() {
371    return reinterpret_cast<roots_iterator>(Roots.end());
372  }
373
374  const_roots_iterator roots_begin() const {
375    return const_cast<ExplodedGraph>(this)->roots_begin();
376  }
377
378  const_roots_iterator roots_end() const {
379    return const_cast<ExplodedGraph>(this)->roots_end();
380  }
381
382  eop_iterator eop_begin() {
383    return reinterpret_cast<eop_iterator>(EndNodes.begin());
384  }
385
386  eop_iterator eop_end() {
387    return reinterpret_cast<eop_iterator>(EndNodes.end());
388  }
389
390  const_eop_iterator eop_begin() const {
391    return const_cast<ExplodedGraph>(this)->eop_begin();
392  }
393
394  const_eop_iterator eop_end() const {
395    return const_cast<ExplodedGraph>(this)->eop_end();
396  }
397
398  // Utility.
399
400  ExplodedGraph* Trim(NodeTy** NBeg, NodeTy** NEnd) const {
401
402    if (NBeg == NEnd)
403      return NULL;
404
405    assert (NBeg < NEnd);
406
407    ExplodedNodeImpl** NBegImpl = (ExplodedNodeImpl**) NBeg;
408    ExplodedNodeImpl** NEndImpl = (ExplodedNodeImpl**) NEnd;
409
410    return static_cast<ExplodedGraph*>(ExplodedGraphImpl::Trim(NBegImpl,
411                                                               NEndImpl));
412  }
413};
414
415
416template <typename StateTy>
417class ExplodedNodeSet {
418
419  typedef ExplodedNode<StateTy>        NodeTy;
420  typedef llvm::SmallPtrSet<NodeTy*,5> ImplTy;
421  ImplTy Impl;
422
423public:
424  ExplodedNodeSet(NodeTy* N) {
425    assert (N && !static_cast<ExplodedNodeImpl*>(N)->isSink());
426    Impl.insert(N);
427  }
428
429  ExplodedNodeSet() {}
430
431  inline void Add(NodeTy* N) {
432    if (N && !static_cast<ExplodedNodeImpl*>(N)->isSink()) Impl.insert(N);
433  }
434
435  typedef typename ImplTy::iterator       iterator;
436  typedef typename ImplTy::const_iterator const_iterator;
437
438  inline unsigned size() const { return Impl.size();  }
439  inline bool empty()    const { return Impl.empty(); }
440
441  inline void clear() { Impl.clear(); }
442
443  inline iterator begin() { return Impl.begin(); }
444  inline iterator end()   { return Impl.end();   }
445
446  inline const_iterator begin() const { return Impl.begin(); }
447  inline const_iterator end()   const { return Impl.end();   }
448};
449
450} // end clang namespace
451
452// GraphTraits
453
454namespace llvm {
455  template<typename StateTy>
456  struct GraphTraits<clang::ExplodedNode<StateTy>*> {
457    typedef clang::ExplodedNode<StateTy>      NodeType;
458    typedef typename NodeType::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  template<typename StateTy>
483  struct GraphTraits<const clang::ExplodedNode<StateTy>*> {
484    typedef const clang::ExplodedNode<StateTy> NodeType;
485    typedef typename NodeType::succ_iterator   ChildIteratorType;
486    typedef llvm::df_iterator<NodeType*>       nodes_iterator;
487
488    static inline NodeType* getEntryNode(NodeType* N) {
489      return N;
490    }
491
492    static inline ChildIteratorType child_begin(NodeType* N) {
493      return N->succ_begin();
494    }
495
496    static inline ChildIteratorType child_end(NodeType* N) {
497      return N->succ_end();
498    }
499
500    static inline nodes_iterator nodes_begin(NodeType* N) {
501      return df_begin(N);
502    }
503
504    static inline nodes_iterator nodes_end(NodeType* N) {
505      return df_end(N);
506    }
507  };
508
509} // end llvm namespace
510
511#endif
512