ExprEngine.h revision 3bbd8cd831788c506f2980293eb3c7e1b3ca2501 
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
93  /// The information about functions shared by the whole translation unit.
94  /// (This data is owned by AnalysisConsumer.)
95  FunctionSummariesTy *FunctionSummaries;
96
97public:
98  ExprEngine(AnalysisManager &mgr, bool gcEnabled, SetOfDecls *VisitedCallees,
99             FunctionSummariesTy *FS);
100
101  ~ExprEngine();
102
103  /// Returns true if there is still simulation state on the worklist.
104  bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
105    return Engine.ExecuteWorkList(L, Steps, 0);
106  }
107
108  /// Execute the work list with an initial state. Nodes that reaches the exit
109  /// of the function are added into the Dst set, which represent the exit
110  /// state of the function call. Returns true if there is still simulation
111  /// state on the worklist.
112  bool ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
113                                       ProgramStateRef InitState,
114                                       ExplodedNodeSet &Dst) {
115    return Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
116  }
117
118  /// getContext - Return the ASTContext associated with this analysis.
119  ASTContext &getContext() const { return AMgr.getASTContext(); }
120
121  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
122
123  CheckerManager &getCheckerManager() const {
124    return *AMgr.getCheckerManager();
125  }
126
127  SValBuilder &getSValBuilder() { return svalBuilder; }
128
129  BugReporter& getBugReporter() { return BR; }
130
131  const NodeBuilderContext &getBuilderContext() {
132    assert(currentBuilderContext);
133    return *currentBuilderContext;
134  }
135
136  bool isObjCGCEnabled() { return ObjCGCEnabled; }
137
138  const Stmt *getStmt() const;
139
140  void GenerateAutoTransition(ExplodedNode *N);
141  void enqueueEndOfPath(ExplodedNodeSet &S);
142  void GenerateCallExitNode(ExplodedNode *N);
143
144  /// ViewGraph - Visualize the ExplodedGraph created by executing the
145  ///  simulation.
146  void ViewGraph(bool trim = false);
147
148  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
149
150  /// getInitialState - Return the initial state used for the root vertex
151  ///  in the ExplodedGraph.
152  ProgramStateRef getInitialState(const LocationContext *InitLoc);
153
154  ExplodedGraph& getGraph() { return G; }
155  const ExplodedGraph& getGraph() const { return G; }
156
157  /// processCFGElement - Called by CoreEngine. Used to generate new successor
158  ///  nodes by processing the 'effects' of a CFG element.
159  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
160                         unsigned StmtIdx, NodeBuilderContext *Ctx);
161
162  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
163
164  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
165
166  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
167
168  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
169                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
170  void ProcessBaseDtor(const CFGBaseDtor D,
171                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
172  void ProcessMemberDtor(const CFGMemberDtor D,
173                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
174  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
175                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
176
177  /// Called by CoreEngine when processing the entrance of a CFGBlock.
178  virtual void processCFGBlockEntrance(const BlockEdge &L,
179                                       NodeBuilderWithSinks &nodeBuilder);
180
181  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
182  ///  nodes by processing the 'effects' of a branch condition.
183  void processBranch(const Stmt *Condition, const Stmt *Term,
184                     NodeBuilderContext& BuilderCtx,
185                     ExplodedNode *Pred,
186                     ExplodedNodeSet &Dst,
187                     const CFGBlock *DstT,
188                     const CFGBlock *DstF);
189
190  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
191  ///  nodes by processing the 'effects' of a computed goto jump.
192  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
193
194  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
195  ///  nodes by processing the 'effects' of a switch statement.
196  void processSwitch(SwitchNodeBuilder& builder);
197
198  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
199  ///  nodes when the control reaches the end of a function.
200  void processEndOfFunction(NodeBuilderContext& BC);
201
202  /// Generate the entry node of the callee.
203  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
204
205  /// Generate the first post callsite node.
206  void processCallExit(ExplodedNode *Pred);
207
208  /// Called by CoreEngine when the analysis worklist has terminated.
209  void processEndWorklist(bool hasWorkRemaining);
210
211  /// evalAssume - Callback function invoked by the ConstraintManager when
212  ///  making assumptions about state values.
213  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
214
215  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
216  ///  region change should trigger a processRegionChanges update.
217  bool wantsRegionChangeUpdate(ProgramStateRef state);
218
219  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
220  ///  to the store. Used to update checkers that track region values.
221  ProgramStateRef
222  processRegionChanges(ProgramStateRef state,
223                       const StoreManager::InvalidatedSymbols *invalidated,
224                       ArrayRef<const MemRegion *> ExplicitRegions,
225                       ArrayRef<const MemRegion *> Regions,
226                       const CallOrObjCMessage *Call);
227
228  /// printState - Called by ProgramStateManager to print checker-specific data.
229  void printState(raw_ostream &Out, ProgramStateRef State,
230                  const char *NL, const char *Sep);
231
232  virtual ProgramStateManager& getStateManager() { return StateMgr; }
233
234  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
235
236  ConstraintManager& getConstraintManager() {
237    return StateMgr.getConstraintManager();
238  }
239
240  // FIXME: Remove when we migrate over to just using SValBuilder.
241  BasicValueFactory& getBasicVals() {
242    return StateMgr.getBasicVals();
243  }
244  const BasicValueFactory& getBasicVals() const {
245    return StateMgr.getBasicVals();
246  }
247
248  // FIXME: Remove when we migrate over to just using ValueManager.
249  SymbolManager& getSymbolManager() { return SymMgr; }
250  const SymbolManager& getSymbolManager() const { return SymMgr; }
251
252  // Functions for external checking of whether we have unfinished work
253  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
254  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
255  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
256
257  const CoreEngine &getCoreEngine() const { return Engine; }
258
259public:
260  /// Visit - Transfer function logic for all statements.  Dispatches to
261  ///  other functions that handle specific kinds of statements.
262  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
263
264  /// VisitArraySubscriptExpr - Transfer function for array accesses.
265  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
266                                   ExplodedNode *Pred,
267                                   ExplodedNodeSet &Dst);
268
269  /// VisitAsmStmt - Transfer function logic for inline asm.
270  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
271
272  /// VisitBlockExpr - Transfer function logic for BlockExprs.
273  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
274                      ExplodedNodeSet &Dst);
275
276  /// VisitBinaryOperator - Transfer function logic for binary operators.
277  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
278                           ExplodedNodeSet &Dst);
279
280
281  /// VisitCall - Transfer function for function calls.
282  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
283                     ExplodedNodeSet &Dst);
284
285  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
286  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
287                ExplodedNodeSet &Dst);
288
289  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
290  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
291                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
292
293  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
294  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
295                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
296
297  /// VisitDeclStmt - Transfer function logic for DeclStmts.
298  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
299                     ExplodedNodeSet &Dst);
300
301  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
302  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
303                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
304
305  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
306                         ExplodedNodeSet &Dst);
307
308  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
309  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
310                        ExplodedNodeSet &Dst);
311
312  /// VisitMemberExpr - Transfer function for member expressions.
313  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
314                           ExplodedNodeSet &Dst);
315
316  /// Transfer function logic for ObjCAtSynchronizedStmts.
317  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
318                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
319
320  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
321  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
322                                ExplodedNodeSet &Dst);
323
324  /// VisitObjCForCollectionStmt - Transfer function logic for
325  ///  ObjCForCollectionStmt.
326  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
327                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
328
329  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNode *Pred,
330                        ExplodedNodeSet &Dst);
331
332  /// VisitReturnStmt - Transfer function logic for return statements.
333  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
334                       ExplodedNodeSet &Dst);
335
336  /// VisitOffsetOfExpr - Transfer function for offsetof.
337  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
338                         ExplodedNodeSet &Dst);
339
340  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
341  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
342                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
343
344  /// VisitUnaryOperator - Transfer function logic for unary operators.
345  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
346                          ExplodedNodeSet &Dst);
347
348  /// Handle ++ and -- (both pre- and post-increment).
349  void VisitIncrementDecrementOperator(const UnaryOperator* U,
350                                       ExplodedNode *Pred,
351                                       ExplodedNodeSet &Dst);
352
353  void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
354                         ExplodedNodeSet &Dst);
355
356  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
357                        ExplodedNodeSet & Dst);
358
359  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
360                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
361
362  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
363                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
364
365  void VisitCXXDestructor(const CXXDestructorDecl *DD,
366                          const MemRegion *Dest, const Stmt *S,
367                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
368
369  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
370                       ExplodedNodeSet &Dst);
371
372  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
373                          ExplodedNodeSet &Dst);
374
375  /// Create a C++ temporary object for an rvalue.
376  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
377                                ExplodedNode *Pred,
378                                ExplodedNodeSet &Dst);
379
380  /// Synthesize CXXThisRegion.
381  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
382                                        const StackFrameContext *SFC);
383
384  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
385                                        const StackFrameContext *frameCtx);
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
440public:
441  // FIXME: 'tag' should be removed, and a LocationContext should be used
442  // instead.
443  // FIXME: Comment on the meaning of the arguments, when 'St' may not
444  // be the same as Pred->state, and when 'location' may not be the
445  // same as state->getLValue(Ex).
446  /// Simulate a read of the result of Ex.
447  void evalLoad(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
448                ProgramStateRef St, SVal location, const ProgramPointTag *tag = 0,
449                QualType LoadTy = QualType());
450
451  // FIXME: 'tag' should be removed, and a LocationContext should be used
452  // instead.
453  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
454                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
455                 const ProgramPointTag *tag = 0);
456private:
457  void evalLoadCommon(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
458                      ProgramStateRef St, SVal location, const ProgramPointTag *tag,
459                      QualType LoadTy);
460
461  // FIXME: 'tag' should be removed, and a LocationContext should be used
462  // instead.
463  void evalLocation(ExplodedNodeSet &Dst, const Stmt *S, ExplodedNode *Pred,
464                    ProgramStateRef St, SVal location,
465                    const ProgramPointTag *tag, bool isLoad);
466
467  bool shouldInlineDecl(const FunctionDecl *FD, ExplodedNode *Pred);
468  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
469
470  bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC);
471};
472
473/// Traits for storing the call processing policy inside GDM.
474/// The GDM stores the corresponding CallExpr pointer.
475struct ReplayWithoutInlining{};
476template <>
477struct ProgramStateTrait<ReplayWithoutInlining> :
478  public ProgramStatePartialTrait<void*> {
479  static void *GDMIndex() { static int index = 0; return &index; }
480};
481
482} // end ento namespace
483
484} // end clang namespace
485
486#endif
487