ExprEngine.h revision 3fd5f370a28552976c52e76c3035d79012d78dda 
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/BugReporter/BugReporter.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/Type.h"
26
27namespace clang {
28
29class AnalysisDeclContextManager;
30class CXXConstructExpr;
31class CXXDeleteExpr;
32class CXXNewExpr;
33class CXXTemporaryObjectExpr;
34class CXXThisExpr;
35class MaterializeTemporaryExpr;
36class ObjCAtSynchronizedStmt;
37class ObjCForCollectionStmt;
38
39namespace ento {
40
41class AnalysisManager;
42class CallOrObjCMessage;
43class ObjCMessage;
44
45class ExprEngine : public SubEngine {
46  AnalysisManager &AMgr;
47
48  AnalysisDeclContextManager &AnalysisDeclContexts;
49
50  CoreEngine Engine;
51
52  /// G - the simulation graph.
53  ExplodedGraph& G;
54
55  /// StateMgr - Object that manages the data for all created states.
56  ProgramStateManager StateMgr;
57
58  /// SymMgr - Object that manages the symbol information.
59  SymbolManager& SymMgr;
60
61  /// svalBuilder - SValBuilder object that creates SVals from expressions.
62  SValBuilder &svalBuilder;
63
64  /// EntryNode - The immediate predecessor node.
65  ExplodedNode *EntryNode;
66
67  /// CleanedState - The state for EntryNode "cleaned" of all dead
68  ///  variables and symbols (as determined by a liveness analysis).
69  ProgramStateRef CleanedState;
70
71  /// currentStmt - The current block-level statement.
72  const Stmt *currentStmt;
73  unsigned int currentStmtIdx;
74  const NodeBuilderContext *currentBuilderContext;
75
76  /// Obj-C Class Identifiers.
77  IdentifierInfo* NSExceptionII;
78
79  /// Obj-C Selectors.
80  Selector* NSExceptionInstanceRaiseSelectors;
81  Selector RaiseSel;
82
83  /// Whether or not GC is enabled in this analysis.
84  bool ObjCGCEnabled;
85
86  /// The BugReporter associated with this engine.  It is important that
87  ///  this object be placed at the very end of member variables so that its
88  ///  destructor is called before the rest of the ExprEngine is destroyed.
89  GRBugReporter BR;
90
91public:
92  ExprEngine(AnalysisManager &mgr, bool gcEnabled, SetOfDecls *VisitedCallees);
93
94  ~ExprEngine();
95
96  void ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
97    Engine.ExecuteWorkList(L, Steps, 0);
98  }
99
100  /// Execute the work list with an initial state. Nodes that reaches the exit
101  /// of the function are added into the Dst set, which represent the exit
102  /// state of the function call.
103  void ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
104                                       ProgramStateRef InitState,
105                                       ExplodedNodeSet &Dst) {
106    Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
107  }
108
109  /// getContext - Return the ASTContext associated with this analysis.
110  ASTContext &getContext() const { return AMgr.getASTContext(); }
111
112  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
113
114  CheckerManager &getCheckerManager() const {
115    return *AMgr.getCheckerManager();
116  }
117
118  SValBuilder &getSValBuilder() { return svalBuilder; }
119
120  BugReporter& getBugReporter() { return BR; }
121
122  const NodeBuilderContext &getBuilderContext() {
123    assert(currentBuilderContext);
124    return *currentBuilderContext;
125  }
126
127  bool isObjCGCEnabled() { return ObjCGCEnabled; }
128
129  const Stmt *getStmt() const;
130
131  void GenerateAutoTransition(ExplodedNode *N);
132  void enqueueEndOfPath(ExplodedNodeSet &S);
133  void GenerateCallExitNode(ExplodedNode *N);
134
135  /// ViewGraph - Visualize the ExplodedGraph created by executing the
136  ///  simulation.
137  void ViewGraph(bool trim = false);
138
139  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
140
141  /// getInitialState - Return the initial state used for the root vertex
142  ///  in the ExplodedGraph.
143  ProgramStateRef getInitialState(const LocationContext *InitLoc);
144
145  ExplodedGraph& getGraph() { return G; }
146  const ExplodedGraph& getGraph() const { return G; }
147
148  /// processCFGElement - Called by CoreEngine. Used to generate new successor
149  ///  nodes by processing the 'effects' of a CFG element.
150  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
151                         unsigned StmtIdx, NodeBuilderContext *Ctx);
152
153  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
154
155  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
156
157  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
158
159  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
160                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
161  void ProcessBaseDtor(const CFGBaseDtor D,
162                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
163  void ProcessMemberDtor(const CFGMemberDtor D,
164                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
165  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
166                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
167
168  /// Called by CoreEngine when processing the entrance of a CFGBlock.
169  virtual void processCFGBlockEntrance(NodeBuilderWithSinks &nodeBuilder);
170
171  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
172  ///  nodes by processing the 'effects' of a branch condition.
173  void processBranch(const Stmt *Condition, const Stmt *Term,
174                     NodeBuilderContext& BuilderCtx,
175                     ExplodedNode *Pred,
176                     ExplodedNodeSet &Dst,
177                     const CFGBlock *DstT,
178                     const CFGBlock *DstF);
179
180  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
181  ///  nodes by processing the 'effects' of a computed goto jump.
182  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
183
184  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
185  ///  nodes by processing the 'effects' of a switch statement.
186  void processSwitch(SwitchNodeBuilder& builder);
187
188  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
189  ///  nodes when the control reaches the end of a function.
190  void processEndOfFunction(NodeBuilderContext& BC);
191
192  /// Generate the entry node of the callee.
193  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
194
195  /// Generate the first post callsite node.
196  void processCallExit(ExplodedNode *Pred);
197
198  /// Called by CoreEngine when the analysis worklist has terminated.
199  void processEndWorklist(bool hasWorkRemaining);
200
201  /// evalAssume - Callback function invoked by the ConstraintManager when
202  ///  making assumptions about state values.
203  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
204
205  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
206  ///  region change should trigger a processRegionChanges update.
207  bool wantsRegionChangeUpdate(ProgramStateRef state);
208
209  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
210  ///  to the store. Used to update checkers that track region values.
211  ProgramStateRef
212  processRegionChanges(ProgramStateRef state,
213                       const StoreManager::InvalidatedSymbols *invalidated,
214                       ArrayRef<const MemRegion *> ExplicitRegions,
215                       ArrayRef<const MemRegion *> Regions,
216                       const CallOrObjCMessage *Call);
217
218  /// printState - Called by ProgramStateManager to print checker-specific data.
219  void printState(raw_ostream &Out, ProgramStateRef State,
220                  const char *NL, const char *Sep);
221
222  virtual ProgramStateManager& getStateManager() { return StateMgr; }
223
224  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
225
226  ConstraintManager& getConstraintManager() {
227    return StateMgr.getConstraintManager();
228  }
229
230  // FIXME: Remove when we migrate over to just using SValBuilder.
231  BasicValueFactory& getBasicVals() {
232    return StateMgr.getBasicVals();
233  }
234  const BasicValueFactory& getBasicVals() const {
235    return StateMgr.getBasicVals();
236  }
237
238  // FIXME: Remove when we migrate over to just using ValueManager.
239  SymbolManager& getSymbolManager() { return SymMgr; }
240  const SymbolManager& getSymbolManager() const { return SymMgr; }
241
242  // Functions for external checking of whether we have unfinished work
243  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
244  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
245  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
246
247  const CoreEngine &getCoreEngine() const { return Engine; }
248
249public:
250  /// Visit - Transfer function logic for all statements.  Dispatches to
251  ///  other functions that handle specific kinds of statements.
252  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
253
254  /// VisitArraySubscriptExpr - Transfer function for array accesses.
255  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
256                                   ExplodedNode *Pred,
257                                   ExplodedNodeSet &Dst);
258
259  /// VisitAsmStmt - Transfer function logic for inline asm.
260  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
261
262  /// VisitBlockExpr - Transfer function logic for BlockExprs.
263  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
264                      ExplodedNodeSet &Dst);
265
266  /// VisitBinaryOperator - Transfer function logic for binary operators.
267  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
268                           ExplodedNodeSet &Dst);
269
270
271  /// VisitCall - Transfer function for function calls.
272  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
273                     ExplodedNodeSet &Dst);
274
275  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
276  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
277                ExplodedNodeSet &Dst);
278
279  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
280  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
281                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
282
283  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
284  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
285                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
286
287  /// VisitDeclStmt - Transfer function logic for DeclStmts.
288  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
289                     ExplodedNodeSet &Dst);
290
291  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
292  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
293                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
294
295  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
296                         ExplodedNodeSet &Dst);
297
298  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
299  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
300                        ExplodedNodeSet &Dst);
301
302  /// VisitMemberExpr - Transfer function for member expressions.
303  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
304                           ExplodedNodeSet &Dst);
305
306  /// Transfer function logic for ObjCAtSynchronizedStmts.
307  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
308                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
309
310  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
311  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
312                                ExplodedNodeSet &Dst);
313
314  /// VisitObjCForCollectionStmt - Transfer function logic for
315  ///  ObjCForCollectionStmt.
316  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
317                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
318
319  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNode *Pred,
320                        ExplodedNodeSet &Dst);
321
322  /// VisitReturnStmt - Transfer function logic for return statements.
323  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
324                       ExplodedNodeSet &Dst);
325
326  /// VisitOffsetOfExpr - Transfer function for offsetof.
327  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
328                         ExplodedNodeSet &Dst);
329
330  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
331  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
332                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
333
334  /// VisitUnaryOperator - Transfer function logic for unary operators.
335  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
336                          ExplodedNodeSet &Dst);
337
338  /// Handle ++ and -- (both pre- and post-increment).
339  void VisitIncrementDecrementOperator(const UnaryOperator* U,
340                                       ExplodedNode *Pred,
341                                       ExplodedNodeSet &Dst);
342
343  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
344                        ExplodedNodeSet & Dst);
345
346  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
347                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
348
349  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
350                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
351
352  void VisitCXXDestructor(const CXXDestructorDecl *DD,
353                          const MemRegion *Dest, const Stmt *S,
354                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
355
356  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
357                       ExplodedNodeSet &Dst);
358
359  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
360                          ExplodedNodeSet &Dst);
361
362  void VisitAggExpr(const Expr *E, const MemRegion *Dest, ExplodedNode *Pred,
363                    ExplodedNodeSet &Dst);
364
365  /// Create a C++ temporary object for an rvalue.
366  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
367                                ExplodedNode *Pred,
368                                ExplodedNodeSet &Dst);
369
370  /// Synthesize CXXThisRegion.
371  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
372                                        const StackFrameContext *SFC);
373
374  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
375                                        const StackFrameContext *frameCtx);
376
377  /// Evaluate arguments with a work list algorithm.
378  void evalArguments(ConstExprIterator AI, ConstExprIterator AE,
379                     const FunctionProtoType *FnType,
380                     ExplodedNode *Pred, ExplodedNodeSet &Dst,
381                     bool FstArgAsLValue = false);
382
383  /// Evaluate callee expression (for a function call).
384  void evalCallee(const CallExpr *callExpr, const ExplodedNodeSet &src,
385                  ExplodedNodeSet &dest);
386
387  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
388  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
389  ///  with those assumptions.
390  void evalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
391                         const Expr *Ex);
392
393  std::pair<const ProgramPointTag *, const ProgramPointTag*>
394    getEagerlyAssumeTags();
395
396  SVal evalMinus(SVal X) {
397    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
398  }
399
400  SVal evalComplement(SVal X) {
401    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
402  }
403
404public:
405
406  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
407                 NonLoc L, NonLoc R, QualType T) {
408    return svalBuilder.evalBinOpNN(state, op, L, R, T);
409  }
410
411  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
412                 NonLoc L, SVal R, QualType T) {
413    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
414  }
415
416  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
417                 SVal LHS, SVal RHS, QualType T) {
418    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
419  }
420
421protected:
422  void evalObjCMessage(StmtNodeBuilder &Bldr, const ObjCMessage &msg,
423                       ExplodedNode *Pred, ProgramStateRef state,
424                       bool GenSink);
425
426  ProgramStateRef invalidateArguments(ProgramStateRef State,
427                                          const CallOrObjCMessage &Call,
428                                          const LocationContext *LC);
429
430  ProgramStateRef MarkBranch(ProgramStateRef state,
431                                 const Stmt *Terminator,
432                                 const LocationContext *LCtx,
433                                 bool branchTaken);
434
435  /// evalBind - Handle the semantics of binding a value to a specific location.
436  ///  This method is used by evalStore, VisitDeclStmt, and others.
437  void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred,
438                SVal location, SVal Val, bool atDeclInit = false,
439                ProgramPoint::Kind PP = ProgramPoint::PostStmtKind);
440
441public:
442  // FIXME: 'tag' should be removed, and a LocationContext should be used
443  // instead.
444  // FIXME: Comment on the meaning of the arguments, when 'St' may not
445  // be the same as Pred->state, and when 'location' may not be the
446  // same as state->getLValue(Ex).
447  /// Simulate a read of the result of Ex.
448  void evalLoad(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
449                ProgramStateRef St, SVal location, const ProgramPointTag *tag = 0,
450                QualType LoadTy = QualType());
451
452  // FIXME: 'tag' should be removed, and a LocationContext should be used
453  // instead.
454  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
455                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
456                 const ProgramPointTag *tag = 0);
457private:
458  void evalLoadCommon(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
459                      ProgramStateRef St, SVal location, const ProgramPointTag *tag,
460                      QualType LoadTy);
461
462  // FIXME: 'tag' should be removed, and a LocationContext should be used
463  // instead.
464  void evalLocation(ExplodedNodeSet &Dst, const Stmt *S, ExplodedNode *Pred,
465                    ProgramStateRef St, SVal location,
466                    const ProgramPointTag *tag, bool isLoad);
467
468  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
469};
470
471} // end ento namespace
472
473} // end clang namespace
474
475#endif
476