ExprEngine.h revision fbcb3f11fc90e9f00e6074e9b118b8dc11ca604c 
1//===-- ExprEngine.h - Path-Sensitive Expression-Level Dataflow ---*- 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 a meta-engine for path-sensitive dataflow analysis that
11//  is built on CoreEngine, but provides the boilerplate to execute transfer
12//  functions and build the ExplodedGraph at the expression level.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CLANG_GR_EXPRENGINE
17#define LLVM_CLANG_GR_EXPRENGINE
18
19#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
20#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
21#include "clang/StaticAnalyzer/Core/PathSensitive/CoreEngine.h"
22#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
23#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
24#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
25#include "clang/AST/Expr.h"
26#include "clang/AST/Type.h"
27
28namespace clang {
29
30class AnalysisDeclContextManager;
31class CXXCatchStmt;
32class CXXConstructExpr;
33class CXXDeleteExpr;
34class CXXNewExpr;
35class CXXTemporaryObjectExpr;
36class CXXThisExpr;
37class MaterializeTemporaryExpr;
38class ObjCAtSynchronizedStmt;
39class ObjCForCollectionStmt;
40
41namespace ento {
42
43class AnalysisManager;
44class CallEvent;
45class SimpleCall;
46
47class ExprEngine : public SubEngine {
48  AnalysisManager &AMgr;
49
50  AnalysisDeclContextManager &AnalysisDeclContexts;
51
52  CoreEngine Engine;
53
54  /// G - the simulation graph.
55  ExplodedGraph& G;
56
57  /// StateMgr - Object that manages the data for all created states.
58  ProgramStateManager StateMgr;
59
60  /// SymMgr - Object that manages the symbol information.
61  SymbolManager& SymMgr;
62
63  /// svalBuilder - SValBuilder object that creates SVals from expressions.
64  SValBuilder &svalBuilder;
65
66  /// EntryNode - The immediate predecessor node.
67  ExplodedNode *EntryNode;
68
69  /// CleanedState - The state for EntryNode "cleaned" of all dead
70  ///  variables and symbols (as determined by a liveness analysis).
71  ProgramStateRef CleanedState;
72
73  /// currStmt - The current block-level statement.
74  const Stmt *currStmt;
75  unsigned int currStmtIdx;
76  const NodeBuilderContext *currBldrCtx;
77
78  /// Obj-C Class Identifiers.
79  IdentifierInfo* NSExceptionII;
80
81  /// Obj-C Selectors.
82  Selector* NSExceptionInstanceRaiseSelectors;
83  Selector RaiseSel;
84
85  /// Whether or not GC is enabled in this analysis.
86  bool ObjCGCEnabled;
87
88  /// The BugReporter associated with this engine.  It is important that
89  ///  this object be placed at the very end of member variables so that its
90  ///  destructor is called before the rest of the ExprEngine is destroyed.
91  GRBugReporter BR;
92
93  /// The functions which have been analyzed through inlining. This is owned by
94  /// AnalysisConsumer. It can be null.
95  SetOfConstDecls *VisitedCallees;
96
97public:
98  ExprEngine(AnalysisManager &mgr, bool gcEnabled,
99             SetOfConstDecls *VisitedCalleesIn,
100             FunctionSummariesTy *FS);
101
102  ~ExprEngine();
103
104  /// Returns true if there is still simulation state on the worklist.
105  bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
106    return Engine.ExecuteWorkList(L, Steps, 0);
107  }
108
109  /// Execute the work list with an initial state. Nodes that reaches the exit
110  /// of the function are added into the Dst set, which represent the exit
111  /// state of the function call. Returns true if there is still simulation
112  /// state on the worklist.
113  bool ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
114                                       ProgramStateRef InitState,
115                                       ExplodedNodeSet &Dst) {
116    return Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
117  }
118
119  /// getContext - Return the ASTContext associated with this analysis.
120  ASTContext &getContext() const { return AMgr.getASTContext(); }
121
122  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
123
124  CheckerManager &getCheckerManager() const {
125    return *AMgr.getCheckerManager();
126  }
127
128  SValBuilder &getSValBuilder() { return svalBuilder; }
129
130  BugReporter& getBugReporter() { return BR; }
131
132  const NodeBuilderContext &getBuilderContext() {
133    assert(currBldrCtx);
134    return *currBldrCtx;
135  }
136
137  bool isObjCGCEnabled() { return ObjCGCEnabled; }
138
139  const Stmt *getStmt() const;
140
141  void GenerateAutoTransition(ExplodedNode *N);
142  void enqueueEndOfPath(ExplodedNodeSet &S);
143  void GenerateCallExitNode(ExplodedNode *N);
144
145  /// ViewGraph - Visualize the ExplodedGraph created by executing the
146  ///  simulation.
147  void ViewGraph(bool trim = false);
148
149  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
150
151  /// getInitialState - Return the initial state used for the root vertex
152  ///  in the ExplodedGraph.
153  ProgramStateRef getInitialState(const LocationContext *InitLoc);
154
155  ExplodedGraph& getGraph() { return G; }
156  const ExplodedGraph& getGraph() const { return G; }
157
158  /// \brief Run the analyzer's garbage collection - remove dead symbols and
159  /// bindings.
160  ///
161  /// \param Node - The predecessor node, from which the processing should
162  /// start.
163  /// \param Out - The returned set of output nodes.
164  /// \param ReferenceStmt - Run garbage collection using the symbols,
165  /// which are live before the given statement.
166  /// \param LC - The location context of the ReferenceStmt.
167  /// \param DiagnosticStmt - the statement used to associate the diagnostic
168  /// message, if any warnings should occur while removing the dead (leaks
169  /// are usually reported here).
170  /// \param K - In some cases it is possible to use PreStmt kind. (Do
171  /// not use it unless you know what you are doing.)
172  void removeDead(ExplodedNode *Node, ExplodedNodeSet &Out,
173            const Stmt *ReferenceStmt, const LocationContext *LC,
174            const Stmt *DiagnosticStmt,
175            ProgramPoint::Kind K = ProgramPoint::PreStmtPurgeDeadSymbolsKind);
176
177  /// processCFGElement - Called by CoreEngine. Used to generate new successor
178  ///  nodes by processing the 'effects' of a CFG element.
179  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
180                         unsigned StmtIdx, NodeBuilderContext *Ctx);
181
182  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
183
184  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
185
186  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
187
188  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
189                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
190  void ProcessBaseDtor(const CFGBaseDtor D,
191                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
192  void ProcessMemberDtor(const CFGMemberDtor D,
193                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
194  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
195                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
196
197  /// Called by CoreEngine when processing the entrance of a CFGBlock.
198  virtual void processCFGBlockEntrance(const BlockEdge &L,
199                                       NodeBuilderWithSinks &nodeBuilder);
200
201  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
202  ///  nodes by processing the 'effects' of a branch condition.
203  void processBranch(const Stmt *Condition, const Stmt *Term,
204                     NodeBuilderContext& BuilderCtx,
205                     ExplodedNode *Pred,
206                     ExplodedNodeSet &Dst,
207                     const CFGBlock *DstT,
208                     const CFGBlock *DstF);
209
210  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
211  ///  nodes by processing the 'effects' of a computed goto jump.
212  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
213
214  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
215  ///  nodes by processing the 'effects' of a switch statement.
216  void processSwitch(SwitchNodeBuilder& builder);
217
218  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
219  ///  nodes when the control reaches the end of a function.
220  void processEndOfFunction(NodeBuilderContext& BC);
221
222  /// Generate the entry node of the callee.
223  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
224
225  /// Generate the sequence of nodes that simulate the call exit and the post
226  /// visit for CallExpr.
227  void processCallExit(ExplodedNode *Pred);
228
229  /// Called by CoreEngine when the analysis worklist has terminated.
230  void processEndWorklist(bool hasWorkRemaining);
231
232  /// evalAssume - Callback function invoked by the ConstraintManager when
233  ///  making assumptions about state values.
234  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
235
236  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
237  ///  region change should trigger a processRegionChanges update.
238  bool wantsRegionChangeUpdate(ProgramStateRef state);
239
240  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
241  ///  to the store. Used to update checkers that track region values.
242  ProgramStateRef
243  processRegionChanges(ProgramStateRef state,
244                       const StoreManager::InvalidatedSymbols *invalidated,
245                       ArrayRef<const MemRegion *> ExplicitRegions,
246                       ArrayRef<const MemRegion *> Regions,
247                       const CallEvent *Call);
248
249  /// printState - Called by ProgramStateManager to print checker-specific data.
250  void printState(raw_ostream &Out, ProgramStateRef State,
251                  const char *NL, const char *Sep);
252
253  virtual ProgramStateManager& getStateManager() { return StateMgr; }
254
255  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
256
257  ConstraintManager& getConstraintManager() {
258    return StateMgr.getConstraintManager();
259  }
260
261  // FIXME: Remove when we migrate over to just using SValBuilder.
262  BasicValueFactory& getBasicVals() {
263    return StateMgr.getBasicVals();
264  }
265  const BasicValueFactory& getBasicVals() const {
266    return StateMgr.getBasicVals();
267  }
268
269  // FIXME: Remove when we migrate over to just using ValueManager.
270  SymbolManager& getSymbolManager() { return SymMgr; }
271  const SymbolManager& getSymbolManager() const { return SymMgr; }
272
273  // Functions for external checking of whether we have unfinished work
274  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
275  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
276  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
277
278  const CoreEngine &getCoreEngine() const { return Engine; }
279
280public:
281  /// Visit - Transfer function logic for all statements.  Dispatches to
282  ///  other functions that handle specific kinds of statements.
283  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
284
285  /// VisitArraySubscriptExpr - Transfer function for array accesses.
286  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
287                                   ExplodedNode *Pred,
288                                   ExplodedNodeSet &Dst);
289
290  /// VisitGCCAsmStmt - Transfer function logic for inline asm.
291  void VisitGCCAsmStmt(const GCCAsmStmt *A, ExplodedNode *Pred,
292                       ExplodedNodeSet &Dst);
293
294  /// VisitMSAsmStmt - Transfer function logic for MS inline asm.
295  void VisitMSAsmStmt(const MSAsmStmt *A, ExplodedNode *Pred,
296                      ExplodedNodeSet &Dst);
297
298  /// VisitBlockExpr - Transfer function logic for BlockExprs.
299  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
300                      ExplodedNodeSet &Dst);
301
302  /// VisitBinaryOperator - Transfer function logic for binary operators.
303  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
304                           ExplodedNodeSet &Dst);
305
306
307  /// VisitCall - Transfer function for function calls.
308  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
309                     ExplodedNodeSet &Dst);
310
311  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
312  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
313                ExplodedNodeSet &Dst);
314
315  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
316  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
317                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
318
319  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
320  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
321                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
322
323  /// VisitDeclStmt - Transfer function logic for DeclStmts.
324  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
325                     ExplodedNodeSet &Dst);
326
327  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
328  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
329                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
330
331  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
332                         ExplodedNodeSet &Dst);
333
334  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
335  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
336                        ExplodedNodeSet &Dst);
337
338  /// VisitMemberExpr - Transfer function for member expressions.
339  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
340                           ExplodedNodeSet &Dst);
341
342  /// Transfer function logic for ObjCAtSynchronizedStmts.
343  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
344                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
345
346  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
347  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
348                                ExplodedNodeSet &Dst);
349
350  /// VisitObjCForCollectionStmt - Transfer function logic for
351  ///  ObjCForCollectionStmt.
352  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
353                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
354
355  void VisitObjCMessage(const ObjCMessageExpr *ME, ExplodedNode *Pred,
356                        ExplodedNodeSet &Dst);
357
358  /// VisitReturnStmt - Transfer function logic for return statements.
359  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
360                       ExplodedNodeSet &Dst);
361
362  /// VisitOffsetOfExpr - Transfer function for offsetof.
363  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
364                         ExplodedNodeSet &Dst);
365
366  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
367  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
368                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
369
370  /// VisitUnaryOperator - Transfer function logic for unary operators.
371  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
372                          ExplodedNodeSet &Dst);
373
374  /// Handle ++ and -- (both pre- and post-increment).
375  void VisitIncrementDecrementOperator(const UnaryOperator* U,
376                                       ExplodedNode *Pred,
377                                       ExplodedNodeSet &Dst);
378
379  void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
380                         ExplodedNodeSet &Dst);
381
382  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
383                        ExplodedNodeSet & Dst);
384
385  void VisitCXXConstructExpr(const CXXConstructExpr *E, ExplodedNode *Pred,
386                             ExplodedNodeSet &Dst);
387
388  void VisitCXXDestructor(QualType ObjectType,
389                          const MemRegion *Dest, const Stmt *S,
390                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
391
392  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
393                       ExplodedNodeSet &Dst);
394
395  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
396                          ExplodedNodeSet &Dst);
397
398  /// Create a C++ temporary object for an rvalue.
399  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
400                                ExplodedNode *Pred,
401                                ExplodedNodeSet &Dst);
402
403  /// evalEagerlyAssumeBinOpBifurcation - Given the nodes in 'Src', eagerly assume symbolic
404  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
405  ///  with those assumptions.
406  void evalEagerlyAssumeBinOpBifurcation(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
407                         const Expr *Ex);
408
409  std::pair<const ProgramPointTag *, const ProgramPointTag*>
410    geteagerlyAssumeBinOpBifurcationTags();
411
412  SVal evalMinus(SVal X) {
413    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
414  }
415
416  SVal evalComplement(SVal X) {
417    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
418  }
419
420public:
421
422  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
423                 NonLoc L, NonLoc R, QualType T) {
424    return svalBuilder.evalBinOpNN(state, op, L, R, T);
425  }
426
427  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
428                 NonLoc L, SVal R, QualType T) {
429    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
430  }
431
432  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
433                 SVal LHS, SVal RHS, QualType T) {
434    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
435  }
436
437protected:
438  /// evalBind - Handle the semantics of binding a value to a specific location.
439  ///  This method is used by evalStore, VisitDeclStmt, and others.
440  void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred,
441                SVal location, SVal Val, bool atDeclInit = false,
442                const ProgramPoint *PP = 0);
443
444public:
445  // FIXME: 'tag' should be removed, and a LocationContext should be used
446  // instead.
447  // FIXME: Comment on the meaning of the arguments, when 'St' may not
448  // be the same as Pred->state, and when 'location' may not be the
449  // same as state->getLValue(Ex).
450  /// Simulate a read of the result of Ex.
451  void evalLoad(ExplodedNodeSet &Dst,
452                const Expr *NodeEx,  /* Eventually will be a CFGStmt */
453                const Expr *BoundExpr,
454                ExplodedNode *Pred,
455                ProgramStateRef St,
456                SVal location,
457                const ProgramPointTag *tag = 0,
458                QualType LoadTy = QualType());
459
460  // FIXME: 'tag' should be removed, and a LocationContext should be used
461  // instead.
462  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
463                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
464                 const ProgramPointTag *tag = 0);
465
466  /// \brief Create a new state in which the call return value is binded to the
467  /// call origin expression.
468  ProgramStateRef bindReturnValue(const CallEvent &Call,
469                                  const LocationContext *LCtx,
470                                  ProgramStateRef State);
471
472  /// Evaluate a call, running pre- and post-call checks and allowing checkers
473  /// to be responsible for handling the evaluation of the call itself.
474  void evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred,
475                const CallEvent &Call);
476
477  /// \brief Default implementation of call evaluation.
478  void defaultEvalCall(NodeBuilder &B, ExplodedNode *Pred,
479                       const CallEvent &Call);
480private:
481  void evalLoadCommon(ExplodedNodeSet &Dst,
482                      const Expr *NodeEx,  /* Eventually will be a CFGStmt */
483                      const Expr *BoundEx,
484                      ExplodedNode *Pred,
485                      ProgramStateRef St,
486                      SVal location,
487                      const ProgramPointTag *tag,
488                      QualType LoadTy);
489
490  // FIXME: 'tag' should be removed, and a LocationContext should be used
491  // instead.
492  void evalLocation(ExplodedNodeSet &Dst,
493                    const Stmt *NodeEx, /* This will eventually be a CFGStmt */
494                    const Stmt *BoundEx,
495                    ExplodedNode *Pred,
496                    ProgramStateRef St, SVal location,
497                    const ProgramPointTag *tag, bool isLoad);
498
499  bool shouldInlineDecl(const Decl *D, ExplodedNode *Pred);
500  bool inlineCall(const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,
501                  ExplodedNode *Pred, ProgramStateRef State);
502
503  /// \brief Conservatively evaluate call by invalidating regions and binding
504  /// a conjured return value.
505  void conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr,
506                            ExplodedNode *Pred, ProgramStateRef State);
507
508  /// \brief Either inline or process the call conservatively (or both), based
509  /// on DynamicDispatchBifurcation data.
510  void BifurcateCall(const MemRegion *BifurReg,
511                     const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,
512                     ExplodedNode *Pred);
513
514  bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC);
515};
516
517/// Traits for storing the call processing policy inside GDM.
518/// The GDM stores the corresponding CallExpr pointer.
519struct ReplayWithoutInlining{};
520template <>
521struct ProgramStateTrait<ReplayWithoutInlining> :
522  public ProgramStatePartialTrait<void*> {
523  static void *GDMIndex() { static int index = 0; return &index; }
524};
525
526} // end ento namespace
527
528} // end clang namespace
529
530#endif
531