ExprEngine.h revision 6a86082f3a06a2dcceaaf63f78a0e52d64bcbaa3 
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 CallOrObjCMessage;
45class ObjCMessage;
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  /// currentStmt - The current block-level statement.
74  const Stmt *currentStmt;
75  unsigned int currentStmtIdx;
76  const NodeBuilderContext *currentBuilderContext;
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(currentBuilderContext);
130    return *currentBuilderContext;
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  /// processCFGElement - Called by CoreEngine. Used to generate new successor
155  ///  nodes by processing the 'effects' of a CFG element.
156  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
157                         unsigned StmtIdx, NodeBuilderContext *Ctx);
158
159  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
160
161  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
162
163  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
164
165  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
166                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
167  void ProcessBaseDtor(const CFGBaseDtor D,
168                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
169  void ProcessMemberDtor(const CFGMemberDtor D,
170                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
171  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
172                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
173
174  /// Called by CoreEngine when processing the entrance of a CFGBlock.
175  virtual void processCFGBlockEntrance(const BlockEdge &L,
176                                       NodeBuilderWithSinks &nodeBuilder);
177
178  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
179  ///  nodes by processing the 'effects' of a branch condition.
180  void processBranch(const Stmt *Condition, const Stmt *Term,
181                     NodeBuilderContext& BuilderCtx,
182                     ExplodedNode *Pred,
183                     ExplodedNodeSet &Dst,
184                     const CFGBlock *DstT,
185                     const CFGBlock *DstF);
186
187  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
188  ///  nodes by processing the 'effects' of a computed goto jump.
189  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
190
191  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
192  ///  nodes by processing the 'effects' of a switch statement.
193  void processSwitch(SwitchNodeBuilder& builder);
194
195  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
196  ///  nodes when the control reaches the end of a function.
197  void processEndOfFunction(NodeBuilderContext& BC);
198
199  /// Generate the entry node of the callee.
200  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
201
202  /// Generate the first post callsite node.
203  void processCallExit(ExplodedNode *Pred);
204
205  /// Called by CoreEngine when the analysis worklist has terminated.
206  void processEndWorklist(bool hasWorkRemaining);
207
208  /// evalAssume - Callback function invoked by the ConstraintManager when
209  ///  making assumptions about state values.
210  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
211
212  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
213  ///  region change should trigger a processRegionChanges update.
214  bool wantsRegionChangeUpdate(ProgramStateRef state);
215
216  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
217  ///  to the store. Used to update checkers that track region values.
218  ProgramStateRef
219  processRegionChanges(ProgramStateRef state,
220                       const StoreManager::InvalidatedSymbols *invalidated,
221                       ArrayRef<const MemRegion *> ExplicitRegions,
222                       ArrayRef<const MemRegion *> Regions,
223                       const CallOrObjCMessage *Call);
224
225  /// printState - Called by ProgramStateManager to print checker-specific data.
226  void printState(raw_ostream &Out, ProgramStateRef State,
227                  const char *NL, const char *Sep);
228
229  virtual ProgramStateManager& getStateManager() { return StateMgr; }
230
231  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
232
233  ConstraintManager& getConstraintManager() {
234    return StateMgr.getConstraintManager();
235  }
236
237  // FIXME: Remove when we migrate over to just using SValBuilder.
238  BasicValueFactory& getBasicVals() {
239    return StateMgr.getBasicVals();
240  }
241  const BasicValueFactory& getBasicVals() const {
242    return StateMgr.getBasicVals();
243  }
244
245  // FIXME: Remove when we migrate over to just using ValueManager.
246  SymbolManager& getSymbolManager() { return SymMgr; }
247  const SymbolManager& getSymbolManager() const { return SymMgr; }
248
249  // Functions for external checking of whether we have unfinished work
250  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
251  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
252  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
253
254  const CoreEngine &getCoreEngine() const { return Engine; }
255
256public:
257  /// Visit - Transfer function logic for all statements.  Dispatches to
258  ///  other functions that handle specific kinds of statements.
259  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
260
261  /// VisitArraySubscriptExpr - Transfer function for array accesses.
262  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
263                                   ExplodedNode *Pred,
264                                   ExplodedNodeSet &Dst);
265
266  /// VisitAsmStmt - Transfer function logic for inline asm.
267  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
268
269  /// VisitBlockExpr - Transfer function logic for BlockExprs.
270  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
271                      ExplodedNodeSet &Dst);
272
273  /// VisitBinaryOperator - Transfer function logic for binary operators.
274  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
275                           ExplodedNodeSet &Dst);
276
277
278  /// VisitCall - Transfer function for function calls.
279  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
280                     ExplodedNodeSet &Dst);
281
282  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
283  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
284                ExplodedNodeSet &Dst);
285
286  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
287  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
288                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
289
290  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
291  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
292                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
293
294  /// VisitDeclStmt - Transfer function logic for DeclStmts.
295  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
296                     ExplodedNodeSet &Dst);
297
298  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
299  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
300                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
301
302  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
303                         ExplodedNodeSet &Dst);
304
305  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
306  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
307                        ExplodedNodeSet &Dst);
308
309  /// VisitMemberExpr - Transfer function for member expressions.
310  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
311                           ExplodedNodeSet &Dst);
312
313  /// Transfer function logic for ObjCAtSynchronizedStmts.
314  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
315                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
316
317  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
318  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
319                                ExplodedNodeSet &Dst);
320
321  /// VisitObjCForCollectionStmt - Transfer function logic for
322  ///  ObjCForCollectionStmt.
323  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
324                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
325
326  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNode *Pred,
327                        ExplodedNodeSet &Dst);
328
329  /// VisitReturnStmt - Transfer function logic for return statements.
330  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
331                       ExplodedNodeSet &Dst);
332
333  /// VisitOffsetOfExpr - Transfer function for offsetof.
334  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
335                         ExplodedNodeSet &Dst);
336
337  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
338  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
339                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
340
341  /// VisitUnaryOperator - Transfer function logic for unary operators.
342  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
343                          ExplodedNodeSet &Dst);
344
345  /// Handle ++ and -- (both pre- and post-increment).
346  void VisitIncrementDecrementOperator(const UnaryOperator* U,
347                                       ExplodedNode *Pred,
348                                       ExplodedNodeSet &Dst);
349
350  void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
351                         ExplodedNodeSet &Dst);
352
353  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
354                        ExplodedNodeSet & Dst);
355
356  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
357                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
358
359  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
360                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
361
362  void VisitCXXDestructor(const CXXDestructorDecl *DD,
363                          const MemRegion *Dest, const Stmt *S,
364                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
365
366  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
367                       ExplodedNodeSet &Dst);
368
369  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
370                          ExplodedNodeSet &Dst);
371
372  /// Create a C++ temporary object for an rvalue.
373  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
374                                ExplodedNode *Pred,
375                                ExplodedNodeSet &Dst);
376
377  /// Synthesize CXXThisRegion.
378  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
379                                        const StackFrameContext *SFC);
380
381  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
382                                        const StackFrameContext *frameCtx);
383
384  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
385  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
386  ///  with those assumptions.
387  void evalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
388                         const Expr *Ex);
389
390  std::pair<const ProgramPointTag *, const ProgramPointTag*>
391    getEagerlyAssumeTags();
392
393  SVal evalMinus(SVal X) {
394    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
395  }
396
397  SVal evalComplement(SVal X) {
398    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
399  }
400
401public:
402
403  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
404                 NonLoc L, NonLoc R, QualType T) {
405    return svalBuilder.evalBinOpNN(state, op, L, R, T);
406  }
407
408  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
409                 NonLoc L, SVal R, QualType T) {
410    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
411  }
412
413  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
414                 SVal LHS, SVal RHS, QualType T) {
415    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
416  }
417
418protected:
419  void evalObjCMessage(StmtNodeBuilder &Bldr, const ObjCMessage &msg,
420                       ExplodedNode *Pred, ProgramStateRef state,
421                       bool GenSink);
422
423  ProgramStateRef invalidateArguments(ProgramStateRef State,
424                                          const CallOrObjCMessage &Call,
425                                          const LocationContext *LC);
426
427  ProgramStateRef MarkBranch(ProgramStateRef state,
428                                 const Stmt *Terminator,
429                                 const LocationContext *LCtx,
430                                 bool branchTaken);
431
432  /// evalBind - Handle the semantics of binding a value to a specific location.
433  ///  This method is used by evalStore, VisitDeclStmt, and others.
434  void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred,
435                SVal location, SVal Val, bool atDeclInit = false);
436
437public:
438  // FIXME: 'tag' should be removed, and a LocationContext should be used
439  // instead.
440  // FIXME: Comment on the meaning of the arguments, when 'St' may not
441  // be the same as Pred->state, and when 'location' may not be the
442  // same as state->getLValue(Ex).
443  /// Simulate a read of the result of Ex.
444  void evalLoad(ExplodedNodeSet &Dst,
445                const Expr *NodeEx,  /* Eventually will be a CFGStmt */
446                const Expr *BoundExpr,
447                ExplodedNode *Pred,
448                ProgramStateRef St,
449                SVal location,
450                const ProgramPointTag *tag = 0,
451                QualType LoadTy = QualType());
452
453  // FIXME: 'tag' should be removed, and a LocationContext should be used
454  // instead.
455  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
456                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
457                 const ProgramPointTag *tag = 0);
458private:
459  void evalLoadCommon(ExplodedNodeSet &Dst,
460                      const Expr *NodeEx,  /* Eventually will be a CFGStmt */
461                      const Expr *BoundEx,
462                      ExplodedNode *Pred,
463                      ProgramStateRef St,
464                      SVal location,
465                      const ProgramPointTag *tag,
466                      QualType LoadTy);
467
468  // FIXME: 'tag' should be removed, and a LocationContext should be used
469  // instead.
470  void evalLocation(ExplodedNodeSet &Dst,
471                    const Stmt *NodeEx, /* This will eventually be a CFGStmt */
472                    const Stmt *BoundEx,
473                    ExplodedNode *Pred,
474                    ProgramStateRef St, SVal location,
475                    const ProgramPointTag *tag, bool isLoad);
476
477  bool shouldInlineDecl(const FunctionDecl *FD, ExplodedNode *Pred);
478  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
479
480  bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC);
481};
482
483/// Traits for storing the call processing policy inside GDM.
484/// The GDM stores the corresponding CallExpr pointer.
485struct ReplayWithoutInlining{};
486template <>
487struct ProgramStateTrait<ReplayWithoutInlining> :
488  public ProgramStatePartialTrait<void*> {
489  static void *GDMIndex() { static int index = 0; return &index; }
490};
491
492} // end ento namespace
493
494} // end clang namespace
495
496#endif
497