ExprEngine.h revision a19f4af7a94835ce4693bfe12d6270754e79eb56 
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/Type.h"
25#include "clang/AST/ExprObjC.h"
26#include "clang/AST/ExprCXX.h"
27#include "clang/AST/StmtObjC.h"
28
29namespace clang {
30
31class ObjCForCollectionStmt;
32
33namespace ento {
34
35class AnalysisManager;
36class CallOrObjCMessage;
37class ObjCMessage;
38
39class ExprEngine : public SubEngine {
40  AnalysisManager &AMgr;
41
42  CoreEngine Engine;
43
44  /// G - the simulation graph.
45  ExplodedGraph& G;
46
47  /// Builder - The current StmtNodeBuilder which is used when building the
48  ///  nodes for a given statement.
49  StmtNodeBuilder* Builder;
50
51  /// StateMgr - Object that manages the data for all created states.
52  ProgramStateManager StateMgr;
53
54  /// SymMgr - Object that manages the symbol information.
55  SymbolManager& SymMgr;
56
57  /// svalBuilder - SValBuilder object that creates SVals from expressions.
58  SValBuilder &svalBuilder;
59
60  /// EntryNode - The immediate predecessor node.
61  ExplodedNode *EntryNode;
62
63  /// CleanedState - The state for EntryNode "cleaned" of all dead
64  ///  variables and symbols (as determined by a liveness analysis).
65  const ProgramState *CleanedState;
66
67  /// currentStmt - The current block-level statement.
68  const Stmt *currentStmt;
69
70  /// Obj-C Class Identifiers.
71  IdentifierInfo* NSExceptionII;
72
73  /// Obj-C Selectors.
74  Selector* NSExceptionInstanceRaiseSelectors;
75  Selector RaiseSel;
76
77  /// Whether or not GC is enabled in this analysis.
78  bool ObjCGCEnabled;
79
80  /// The BugReporter associated with this engine.  It is important that
81  ///  this object be placed at the very end of member variables so that its
82  ///  destructor is called before the rest of the ExprEngine is destroyed.
83  GRBugReporter BR;
84
85public:
86  ExprEngine(AnalysisManager &mgr, bool gcEnabled);
87
88  ~ExprEngine();
89
90  void ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
91    Engine.ExecuteWorkList(L, Steps, 0);
92  }
93
94  /// Execute the work list with an initial state. Nodes that reaches the exit
95  /// of the function are added into the Dst set, which represent the exit
96  /// state of the function call.
97  void ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
98                                       const ProgramState *InitState,
99                                       ExplodedNodeSet &Dst) {
100    Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
101  }
102
103  /// getContext - Return the ASTContext associated with this analysis.
104  ASTContext &getContext() const { return AMgr.getASTContext(); }
105
106  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
107
108  CheckerManager &getCheckerManager() const {
109    return *AMgr.getCheckerManager();
110  }
111
112  SValBuilder &getSValBuilder() { return svalBuilder; }
113
114  BugReporter& getBugReporter() { return BR; }
115
116  StmtNodeBuilder &getBuilder() { assert(Builder); return *Builder; }
117
118  bool isObjCGCEnabled() { return ObjCGCEnabled; }
119
120  /// ViewGraph - Visualize the ExplodedGraph created by executing the
121  ///  simulation.
122  void ViewGraph(bool trim = false);
123
124  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
125
126  /// getInitialState - Return the initial state used for the root vertex
127  ///  in the ExplodedGraph.
128  const ProgramState *getInitialState(const LocationContext *InitLoc);
129
130  ExplodedGraph& getGraph() { return G; }
131  const ExplodedGraph& getGraph() const { return G; }
132
133  /// processCFGElement - Called by CoreEngine. Used to generate new successor
134  ///  nodes by processing the 'effects' of a CFG element.
135  void processCFGElement(const CFGElement E, StmtNodeBuilder& builder);
136
137  void ProcessStmt(const CFGStmt S, StmtNodeBuilder &builder);
138
139  void ProcessInitializer(const CFGInitializer I, StmtNodeBuilder &builder);
140
141  void ProcessImplicitDtor(const CFGImplicitDtor D, StmtNodeBuilder &builder);
142
143  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
144                            StmtNodeBuilder &builder);
145  void ProcessBaseDtor(const CFGBaseDtor D, StmtNodeBuilder &builder);
146  void ProcessMemberDtor(const CFGMemberDtor D, StmtNodeBuilder &builder);
147  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
148                            StmtNodeBuilder &builder);
149
150  /// Called by CoreEngine when processing the entrance of a CFGBlock.
151  virtual void processCFGBlockEntrance(ExplodedNodeSet &dstNodes,
152                                GenericNodeBuilder<BlockEntrance> &nodeBuilder);
153
154  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
155  ///  nodes by processing the 'effects' of a branch condition.
156  void processBranch(const Stmt *Condition, const Stmt *Term,
157                     NodeBuilderContext& BuilderCtx,
158                     const CFGBlock *DstT,
159                     const CFGBlock *DstF);
160
161  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
162  ///  nodes by processing the 'effects' of a computed goto jump.
163  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
164
165  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
166  ///  nodes by processing the 'effects' of a switch statement.
167  void processSwitch(SwitchNodeBuilder& builder);
168
169  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
170  ///  nodes when the control reaches the end of a function.
171  void processEndOfFunction(EndOfFunctionNodeBuilder& builder);
172
173  /// Generate the entry node of the callee.
174  void processCallEnter(CallEnterNodeBuilder &builder);
175
176  /// Generate the first post callsite node.
177  void processCallExit(CallExitNodeBuilder &builder);
178
179  /// Called by CoreEngine when the analysis worklist has terminated.
180  void processEndWorklist(bool hasWorkRemaining);
181
182  /// evalAssume - Callback function invoked by the ConstraintManager when
183  ///  making assumptions about state values.
184  const ProgramState *processAssume(const ProgramState *state, SVal cond,bool assumption);
185
186  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
187  ///  region change should trigger a processRegionChanges update.
188  bool wantsRegionChangeUpdate(const ProgramState *state);
189
190  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
191  ///  to the store. Used to update checkers that track region values.
192  const ProgramState *
193  processRegionChanges(const ProgramState *state,
194                       const StoreManager::InvalidatedSymbols *invalidated,
195                       ArrayRef<const MemRegion *> ExplicitRegions,
196                       ArrayRef<const MemRegion *> Regions);
197
198  /// printState - Called by ProgramStateManager to print checker-specific data.
199  void printState(raw_ostream &Out, const ProgramState *State,
200                  const char *NL, const char *Sep);
201
202  virtual ProgramStateManager& getStateManager() { return StateMgr; }
203
204  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
205
206  ConstraintManager& getConstraintManager() {
207    return StateMgr.getConstraintManager();
208  }
209
210  // FIXME: Remove when we migrate over to just using SValBuilder.
211  BasicValueFactory& getBasicVals() {
212    return StateMgr.getBasicVals();
213  }
214  const BasicValueFactory& getBasicVals() const {
215    return StateMgr.getBasicVals();
216  }
217
218  // FIXME: Remove when we migrate over to just using ValueManager.
219  SymbolManager& getSymbolManager() { return SymMgr; }
220  const SymbolManager& getSymbolManager() const { return SymMgr; }
221
222  // Functions for external checking of whether we have unfinished work
223  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
224  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
225  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
226
227  const CoreEngine &getCoreEngine() const { return Engine; }
228
229public:
230  ExplodedNode *MakeNode(ExplodedNodeSet &Dst, const Stmt *S,
231                         ExplodedNode *Pred, const ProgramState *St,
232                         ProgramPoint::Kind K = ProgramPoint::PostStmtKind,
233                         const ProgramPointTag *tag = 0);
234
235  /// Visit - Transfer function logic for all statements.  Dispatches to
236  ///  other functions that handle specific kinds of statements.
237  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
238
239  /// VisitArraySubscriptExpr - Transfer function for array accesses.
240  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
241                                   ExplodedNode *Pred,
242                                   ExplodedNodeSet &Dst);
243
244  /// VisitAsmStmt - Transfer function logic for inline asm.
245  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
246
247  void VisitAsmStmtHelperOutputs(const AsmStmt *A,
248                                 AsmStmt::const_outputs_iterator I,
249                                 AsmStmt::const_outputs_iterator E,
250                                 ExplodedNode *Pred, ExplodedNodeSet &Dst);
251
252  void VisitAsmStmtHelperInputs(const AsmStmt *A,
253                                AsmStmt::const_inputs_iterator I,
254                                AsmStmt::const_inputs_iterator E,
255                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
256
257  /// VisitBlockExpr - Transfer function logic for BlockExprs.
258  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
259                      ExplodedNodeSet &Dst);
260
261  /// VisitBinaryOperator - Transfer function logic for binary operators.
262  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
263                           ExplodedNodeSet &Dst);
264
265
266  /// VisitCall - Transfer function for function calls.
267  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
268                     ExplodedNodeSet &Dst);
269
270  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
271  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
272                ExplodedNodeSet &Dst);
273
274  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
275  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
276                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
277
278  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
279  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
280                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
281
282  /// VisitDeclStmt - Transfer function logic for DeclStmts.
283  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
284                     ExplodedNodeSet &Dst);
285
286  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
287  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
288                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
289
290  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
291                         ExplodedNodeSet &Dst);
292
293  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
294  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
295                        ExplodedNodeSet &Dst);
296
297  /// VisitMemberExpr - Transfer function for member expressions.
298  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
299                           ExplodedNodeSet &Dst);
300
301  /// Transfer function logic for ObjCAtSynchronizedStmts.
302  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
303                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
304
305  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
306  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
307                                ExplodedNodeSet &Dst);
308
309  /// VisitObjCForCollectionStmt - Transfer function logic for
310  ///  ObjCForCollectionStmt.
311  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
312                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
313
314  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNode *Pred,
315                        ExplodedNodeSet &Dst);
316
317  /// VisitReturnStmt - Transfer function logic for return statements.
318  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
319                       ExplodedNodeSet &Dst);
320
321  /// VisitOffsetOfExpr - Transfer function for offsetof.
322  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
323                         ExplodedNodeSet &Dst);
324
325  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
326  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
327                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
328
329  /// VisitUnaryOperator - Transfer function logic for unary operators.
330  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
331                          ExplodedNodeSet &Dst);
332
333  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
334                        ExplodedNodeSet & Dst);
335
336  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
337                                   ExplodedNode *Pred, ExplodedNodeSet &Dst) {
338    VisitCXXConstructExpr(expr, 0, Pred, Dst);
339  }
340
341  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
342                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
343
344  void VisitCXXDestructor(const CXXDestructorDecl *DD,
345                          const MemRegion *Dest, const Stmt *S,
346                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
347
348  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
349                       ExplodedNodeSet &Dst);
350
351  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
352                          ExplodedNodeSet &Dst);
353
354  void VisitAggExpr(const Expr *E, const MemRegion *Dest, ExplodedNode *Pred,
355                    ExplodedNodeSet &Dst);
356
357  /// Create a C++ temporary object for an rvalue.
358  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
359                                ExplodedNode *Pred,
360                                ExplodedNodeSet &Dst);
361
362  /// Synthesize CXXThisRegion.
363  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
364                                        const StackFrameContext *SFC);
365
366  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
367                                        const StackFrameContext *frameCtx);
368
369  /// Evaluate arguments with a work list algorithm.
370  void evalArguments(ConstExprIterator AI, ConstExprIterator AE,
371                     const FunctionProtoType *FnType,
372                     ExplodedNode *Pred, ExplodedNodeSet &Dst,
373                     bool FstArgAsLValue = false);
374
375  /// Evaluate callee expression (for a function call).
376  void evalCallee(const CallExpr *callExpr, const ExplodedNodeSet &src,
377                  ExplodedNodeSet &dest);
378
379  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
380  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
381  ///  with those assumptions.
382  void evalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
383                         const Expr *Ex);
384
385  std::pair<const ProgramPointTag *, const ProgramPointTag*>
386    getEagerlyAssumeTags();
387
388  SVal evalMinus(SVal X) {
389    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
390  }
391
392  SVal evalComplement(SVal X) {
393    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
394  }
395
396public:
397
398  SVal evalBinOp(const ProgramState *state, BinaryOperator::Opcode op,
399                 NonLoc L, NonLoc R, QualType T) {
400    return svalBuilder.evalBinOpNN(state, op, L, R, T);
401  }
402
403  SVal evalBinOp(const ProgramState *state, BinaryOperator::Opcode op,
404                 NonLoc L, SVal R, QualType T) {
405    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
406  }
407
408  SVal evalBinOp(const ProgramState *ST, BinaryOperator::Opcode Op,
409                 SVal LHS, SVal RHS, QualType T) {
410    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
411  }
412
413protected:
414  void evalObjCMessage(ExplodedNodeSet &Dst, const ObjCMessage &msg,
415                       ExplodedNode *Pred, const ProgramState *state);
416
417  const ProgramState *invalidateArguments(const ProgramState *State,
418                                          const CallOrObjCMessage &Call,
419                                          const LocationContext *LC);
420
421  const ProgramState *MarkBranch(const ProgramState *St, const Stmt *Terminator,
422                            bool branchTaken);
423
424  /// evalBind - Handle the semantics of binding a value to a specific location.
425  ///  This method is used by evalStore, VisitDeclStmt, and others.
426  void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred,
427                SVal location, SVal Val, bool atDeclInit = false);
428
429public:
430  // FIXME: 'tag' should be removed, and a LocationContext should be used
431  // instead.
432  // FIXME: Comment on the meaning of the arguments, when 'St' may not
433  // be the same as Pred->state, and when 'location' may not be the
434  // same as state->getLValue(Ex).
435  /// Simulate a read of the result of Ex.
436  void evalLoad(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
437                const ProgramState *St, SVal location, const ProgramPointTag *tag = 0,
438                QualType LoadTy = QualType());
439
440  // FIXME: 'tag' should be removed, and a LocationContext should be used
441  // instead.
442  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
443                 ExplodedNode *Pred, const ProgramState *St, SVal TargetLV, SVal Val,
444                 const ProgramPointTag *tag = 0);
445private:
446  void evalLoadCommon(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
447                      const ProgramState *St, SVal location, const ProgramPointTag *tag,
448                      QualType LoadTy);
449
450  // FIXME: 'tag' should be removed, and a LocationContext should be used
451  // instead.
452  void evalLocation(ExplodedNodeSet &Dst, const Stmt *S, ExplodedNode *Pred,
453                    const ProgramState *St, SVal location,
454                    const ProgramPointTag *tag, bool isLoad);
455
456  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
457
458
459public:
460  /// Returns true if calling the specific function or method would possibly
461  /// cause global variables to be invalidated.
462  bool doesInvalidateGlobals(const CallOrObjCMessage &callOrMessage) const;
463
464};
465
466} // end ento namespace
467
468} // end clang namespace
469
470#endif
471