ExprEngine.h revision 66c486f275531df6362b3511fc3af6563561801b 
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
93public:
94  ExprEngine(AnalysisManager &mgr, bool gcEnabled,
95             SetOfConstDecls *VisitedCallees,
96             FunctionSummariesTy *FS);
97
98  ~ExprEngine();
99
100  /// Returns true if there is still simulation state on the worklist.
101  bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
102    return Engine.ExecuteWorkList(L, Steps, 0);
103  }
104
105  /// Execute the work list with an initial state. Nodes that reaches the exit
106  /// of the function are added into the Dst set, which represent the exit
107  /// state of the function call. Returns true if there is still simulation
108  /// state on the worklist.
109  bool ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
110                                       ProgramStateRef InitState,
111                                       ExplodedNodeSet &Dst) {
112    return Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
113  }
114
115  /// getContext - Return the ASTContext associated with this analysis.
116  ASTContext &getContext() const { return AMgr.getASTContext(); }
117
118  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
119
120  CheckerManager &getCheckerManager() const {
121    return *AMgr.getCheckerManager();
122  }
123
124  SValBuilder &getSValBuilder() { return svalBuilder; }
125
126  BugReporter& getBugReporter() { return BR; }
127
128  const NodeBuilderContext &getBuilderContext() {
129    assert(currBldrCtx);
130    return *currBldrCtx;
131  }
132
133  bool isObjCGCEnabled() { return ObjCGCEnabled; }
134
135  const Stmt *getStmt() const;
136
137  void GenerateAutoTransition(ExplodedNode *N);
138  void enqueueEndOfPath(ExplodedNodeSet &S);
139  void GenerateCallExitNode(ExplodedNode *N);
140
141  /// ViewGraph - Visualize the ExplodedGraph created by executing the
142  ///  simulation.
143  void ViewGraph(bool trim = false);
144
145  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
146
147  /// getInitialState - Return the initial state used for the root vertex
148  ///  in the ExplodedGraph.
149  ProgramStateRef getInitialState(const LocationContext *InitLoc);
150
151  ExplodedGraph& getGraph() { return G; }
152  const ExplodedGraph& getGraph() const { return G; }
153
154  /// \brief Run the analyzer's garbage collection - remove dead symbols and
155  /// bindings.
156  ///
157  /// \param Node - The predecessor node, from which the processing should
158  /// start.
159  /// \param Out - The returned set of output nodes.
160  /// \param ReferenceStmt - Run garbage collection using the symbols,
161  /// which are live before the given statement.
162  /// \param LC - The location context of the ReferenceStmt.
163  /// \param DiagnosticStmt - the statement used to associate the diagnostic
164  /// message, if any warnings should occur while removing the dead (leaks
165  /// are usually reported here).
166  /// \param K - In some cases it is possible to use PreStmt kind. (Do
167  /// not use it unless you know what you are doing.)
168  void removeDead(ExplodedNode *Node, ExplodedNodeSet &Out,
169            const Stmt *ReferenceStmt, const LocationContext *LC,
170            const Stmt *DiagnosticStmt,
171            ProgramPoint::Kind K = ProgramPoint::PreStmtPurgeDeadSymbolsKind);
172
173  /// processCFGElement - Called by CoreEngine. Used to generate new successor
174  ///  nodes by processing the 'effects' of a CFG element.
175  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
176                         unsigned StmtIdx, NodeBuilderContext *Ctx);
177
178  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
179
180  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
181
182  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
183
184  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
185                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
186  void ProcessBaseDtor(const CFGBaseDtor D,
187                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
188  void ProcessMemberDtor(const CFGMemberDtor D,
189                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
190  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
191                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
192
193  /// Called by CoreEngine when processing the entrance of a CFGBlock.
194  virtual void processCFGBlockEntrance(const BlockEdge &L,
195                                       NodeBuilderWithSinks &nodeBuilder);
196
197  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
198  ///  nodes by processing the 'effects' of a branch condition.
199  void processBranch(const Stmt *Condition, const Stmt *Term,
200                     NodeBuilderContext& BuilderCtx,
201                     ExplodedNode *Pred,
202                     ExplodedNodeSet &Dst,
203                     const CFGBlock *DstT,
204                     const CFGBlock *DstF);
205
206  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
207  ///  nodes by processing the 'effects' of a computed goto jump.
208  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
209
210  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
211  ///  nodes by processing the 'effects' of a switch statement.
212  void processSwitch(SwitchNodeBuilder& builder);
213
214  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
215  ///  nodes when the control reaches the end of a function.
216  void processEndOfFunction(NodeBuilderContext& BC);
217
218  /// Generate the entry node of the callee.
219  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
220
221  /// Generate the sequence of nodes that simulate the call exit and the post
222  /// visit for CallExpr.
223  void processCallExit(ExplodedNode *Pred);
224
225  /// Called by CoreEngine when the analysis worklist has terminated.
226  void processEndWorklist(bool hasWorkRemaining);
227
228  /// evalAssume - Callback function invoked by the ConstraintManager when
229  ///  making assumptions about state values.
230  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
231
232  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
233  ///  region change should trigger a processRegionChanges update.
234  bool wantsRegionChangeUpdate(ProgramStateRef state);
235
236  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
237  ///  to the store. Used to update checkers that track region values.
238  ProgramStateRef
239  processRegionChanges(ProgramStateRef state,
240                       const StoreManager::InvalidatedSymbols *invalidated,
241                       ArrayRef<const MemRegion *> ExplicitRegions,
242                       ArrayRef<const MemRegion *> Regions,
243                       const CallEvent *Call);
244
245  /// printState - Called by ProgramStateManager to print checker-specific data.
246  void printState(raw_ostream &Out, ProgramStateRef State,
247                  const char *NL, const char *Sep);
248
249  virtual ProgramStateManager& getStateManager() { return StateMgr; }
250
251  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
252
253  ConstraintManager& getConstraintManager() {
254    return StateMgr.getConstraintManager();
255  }
256
257  // FIXME: Remove when we migrate over to just using SValBuilder.
258  BasicValueFactory& getBasicVals() {
259    return StateMgr.getBasicVals();
260  }
261  const BasicValueFactory& getBasicVals() const {
262    return StateMgr.getBasicVals();
263  }
264
265  // FIXME: Remove when we migrate over to just using ValueManager.
266  SymbolManager& getSymbolManager() { return SymMgr; }
267  const SymbolManager& getSymbolManager() const { return SymMgr; }
268
269  // Functions for external checking of whether we have unfinished work
270  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
271  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
272  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
273
274  const CoreEngine &getCoreEngine() const { return Engine; }
275
276public:
277  /// Visit - Transfer function logic for all statements.  Dispatches to
278  ///  other functions that handle specific kinds of statements.
279  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
280
281  /// VisitArraySubscriptExpr - Transfer function for array accesses.
282  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
283                                   ExplodedNode *Pred,
284                                   ExplodedNodeSet &Dst);
285
286  /// VisitAsmStmt - Transfer function logic for inline asm.
287  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
288
289  /// VisitMSAsmStmt - Transfer function logic for MS inline asm.
290  void VisitMSAsmStmt(const MSAsmStmt *A, ExplodedNode *Pred,
291                      ExplodedNodeSet &Dst);
292
293  /// VisitBlockExpr - Transfer function logic for BlockExprs.
294  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
295                      ExplodedNodeSet &Dst);
296
297  /// VisitBinaryOperator - Transfer function logic for binary operators.
298  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
299                           ExplodedNodeSet &Dst);
300
301
302  /// VisitCall - Transfer function for function calls.
303  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
304                     ExplodedNodeSet &Dst);
305
306  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
307  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
308                ExplodedNodeSet &Dst);
309
310  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
311  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
312                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
313
314  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
315  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
316                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
317
318  /// VisitDeclStmt - Transfer function logic for DeclStmts.
319  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
320                     ExplodedNodeSet &Dst);
321
322  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
323  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
324                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
325
326  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
327                         ExplodedNodeSet &Dst);
328
329  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
330  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
331                        ExplodedNodeSet &Dst);
332
333  /// VisitMemberExpr - Transfer function for member expressions.
334  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
335                           ExplodedNodeSet &Dst);
336
337  /// Transfer function logic for ObjCAtSynchronizedStmts.
338  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
339                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
340
341  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
342  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
343                                ExplodedNodeSet &Dst);
344
345  /// VisitObjCForCollectionStmt - Transfer function logic for
346  ///  ObjCForCollectionStmt.
347  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
348                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
349
350  void VisitObjCMessage(const ObjCMessageExpr *ME, ExplodedNode *Pred,
351                        ExplodedNodeSet &Dst);
352
353  /// VisitReturnStmt - Transfer function logic for return statements.
354  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
355                       ExplodedNodeSet &Dst);
356
357  /// VisitOffsetOfExpr - Transfer function for offsetof.
358  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
359                         ExplodedNodeSet &Dst);
360
361  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
362  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
363                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
364
365  /// VisitUnaryOperator - Transfer function logic for unary operators.
366  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
367                          ExplodedNodeSet &Dst);
368
369  /// Handle ++ and -- (both pre- and post-increment).
370  void VisitIncrementDecrementOperator(const UnaryOperator* U,
371                                       ExplodedNode *Pred,
372                                       ExplodedNodeSet &Dst);
373
374  void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
375                         ExplodedNodeSet &Dst);
376
377  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
378                        ExplodedNodeSet & Dst);
379
380  void VisitCXXConstructExpr(const CXXConstructExpr *E, ExplodedNode *Pred,
381                             ExplodedNodeSet &Dst);
382
383  void VisitCXXDestructor(QualType ObjectType,
384                          const MemRegion *Dest, const Stmt *S,
385                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
386
387  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
388                       ExplodedNodeSet &Dst);
389
390  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
391                          ExplodedNodeSet &Dst);
392
393  /// Create a C++ temporary object for an rvalue.
394  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
395                                ExplodedNode *Pred,
396                                ExplodedNodeSet &Dst);
397
398  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
399  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
400  ///  with those assumptions.
401  void evalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
402                         const Expr *Ex);
403
404  std::pair<const ProgramPointTag *, const ProgramPointTag*>
405    getEagerlyAssumeTags();
406
407  SVal evalMinus(SVal X) {
408    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
409  }
410
411  SVal evalComplement(SVal X) {
412    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
413  }
414
415public:
416
417  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
418                 NonLoc L, NonLoc R, QualType T) {
419    return svalBuilder.evalBinOpNN(state, op, L, R, T);
420  }
421
422  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
423                 NonLoc L, SVal R, QualType T) {
424    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
425  }
426
427  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
428                 SVal LHS, SVal RHS, QualType T) {
429    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
430  }
431
432protected:
433  /// evalBind - Handle the semantics of binding a value to a specific location.
434  ///  This method is used by evalStore, VisitDeclStmt, and others.
435  void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred,
436                SVal location, SVal Val, bool atDeclInit = false);
437
438public:
439  // FIXME: 'tag' should be removed, and a LocationContext should be used
440  // instead.
441  // FIXME: Comment on the meaning of the arguments, when 'St' may not
442  // be the same as Pred->state, and when 'location' may not be the
443  // same as state->getLValue(Ex).
444  /// Simulate a read of the result of Ex.
445  void evalLoad(ExplodedNodeSet &Dst,
446                const Expr *NodeEx,  /* Eventually will be a CFGStmt */
447                const Expr *BoundExpr,
448                ExplodedNode *Pred,
449                ProgramStateRef St,
450                SVal location,
451                const ProgramPointTag *tag = 0,
452                QualType LoadTy = QualType());
453
454  // FIXME: 'tag' should be removed, and a LocationContext should be used
455  // instead.
456  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
457                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
458                 const ProgramPointTag *tag = 0);
459
460  /// \brief Create a new state in which the call return value is binded to the
461  /// call origin expression.
462  ProgramStateRef bindReturnValue(const CallEvent &Call,
463                                  const LocationContext *LCtx,
464                                  ProgramStateRef State);
465
466  /// Evaluate a call, running pre- and post-call checks and allowing checkers
467  /// to be responsible for handling the evaluation of the call itself.
468  void evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred,
469                const CallEvent &Call);
470
471  /// \brief Default implementation of call evaluation.
472  void defaultEvalCall(NodeBuilder &B, ExplodedNode *Pred,
473                       const CallEvent &Call);
474private:
475  void evalLoadCommon(ExplodedNodeSet &Dst,
476                      const Expr *NodeEx,  /* Eventually will be a CFGStmt */
477                      const Expr *BoundEx,
478                      ExplodedNode *Pred,
479                      ProgramStateRef St,
480                      SVal location,
481                      const ProgramPointTag *tag,
482                      QualType LoadTy);
483
484  // FIXME: 'tag' should be removed, and a LocationContext should be used
485  // instead.
486  void evalLocation(ExplodedNodeSet &Dst,
487                    const Stmt *NodeEx, /* This will eventually be a CFGStmt */
488                    const Stmt *BoundEx,
489                    ExplodedNode *Pred,
490                    ProgramStateRef St, SVal location,
491                    const ProgramPointTag *tag, bool isLoad);
492
493  bool shouldInlineDecl(const Decl *D, ExplodedNode *Pred);
494  bool inlineCall(const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,
495                  ExplodedNode *Pred, ProgramStateRef State);
496
497  /// \brief Conservatively evaluate call by invalidating regions and binding
498  /// a conjured return value.
499  void conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr,
500                            ExplodedNode *Pred, ProgramStateRef State);
501
502  /// \brief Either inline or process the call conservatively (or both), based
503  /// on DynamicDispatchBifurcation data.
504  void BifurcateCall(const MemRegion *BifurReg,
505                     const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,
506                     ExplodedNode *Pred);
507
508  bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC);
509};
510
511/// Traits for storing the call processing policy inside GDM.
512/// The GDM stores the corresponding CallExpr pointer.
513struct ReplayWithoutInlining{};
514template <>
515struct ProgramStateTrait<ReplayWithoutInlining> :
516  public ProgramStatePartialTrait<void*> {
517  static void *GDMIndex() { static int index = 0; return &index; }
518};
519
520} // end ento namespace
521
522} // end clang namespace
523
524#endif
525