ExprEngine.h revision e5cfd52a3a5d4bb46f77323fa8fa0b973fcde7bc 
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/GRState.h"
23#include "clang/StaticAnalyzer/Core/PathSensitive/TransferFuncs.h"
24#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h"
25#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
26#include "clang/AST/Type.h"
27#include "clang/AST/ExprObjC.h"
28#include "clang/AST/ExprCXX.h"
29#include "clang/AST/StmtObjC.h"
30
31namespace clang {
32
33class ObjCForCollectionStmt;
34
35namespace ento {
36
37class AnalysisManager;
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  GRStateManager 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 GRState* 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  /// The BugReporter associated with this engine.  It is important that
78  ///  this object be placed at the very end of member variables so that its
79  ///  destructor is called before the rest of the ExprEngine is destroyed.
80  GRBugReporter BR;
81
82  llvm::OwningPtr<TransferFuncs> TF;
83
84public:
85  ExprEngine(AnalysisManager &mgr, TransferFuncs *tf);
86
87  ~ExprEngine();
88
89  void ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
90    Engine.ExecuteWorkList(L, Steps, 0);
91  }
92
93  /// Execute the work list with an initial state. Nodes that reaches the exit
94  /// of the function are added into the Dst set, which represent the exit
95  /// state of the function call.
96  void ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
97                                       const GRState *InitState,
98                                       ExplodedNodeSet &Dst) {
99    Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
100  }
101
102  /// getContext - Return the ASTContext associated with this analysis.
103  ASTContext& getContext() const { return AMgr.getASTContext(); }
104
105  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
106
107  CheckerManager &getCheckerManager() const {
108    return *AMgr.getCheckerManager();
109  }
110
111  SValBuilder &getSValBuilder() { return svalBuilder; }
112
113  TransferFuncs& getTF() { return *TF; }
114
115  BugReporter& getBugReporter() { return BR; }
116
117  StmtNodeBuilder &getBuilder() { assert(Builder); return *Builder; }
118
119  // FIXME: Remove once TransferFuncs is no longer referenced.
120  void setTransferFunction(TransferFuncs* tf);
121
122  /// ViewGraph - Visualize the ExplodedGraph created by executing the
123  ///  simulation.
124  void ViewGraph(bool trim = false);
125
126  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
127
128  /// getInitialState - Return the initial state used for the root vertex
129  ///  in the ExplodedGraph.
130  const GRState* getInitialState(const LocationContext *InitLoc);
131
132  ExplodedGraph& getGraph() { return G; }
133  const ExplodedGraph& getGraph() const { return G; }
134
135  /// processCFGElement - Called by CoreEngine. Used to generate new successor
136  ///  nodes by processing the 'effects' of a CFG element.
137  void processCFGElement(const CFGElement E, StmtNodeBuilder& builder);
138
139  void ProcessStmt(const CFGStmt S, StmtNodeBuilder &builder);
140
141  void ProcessInitializer(const CFGInitializer I, StmtNodeBuilder &builder);
142
143  void ProcessImplicitDtor(const CFGImplicitDtor D, StmtNodeBuilder &builder);
144
145  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
146                            StmtNodeBuilder &builder);
147  void ProcessBaseDtor(const CFGBaseDtor D, StmtNodeBuilder &builder);
148  void ProcessMemberDtor(const CFGMemberDtor D, StmtNodeBuilder &builder);
149  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
150                            StmtNodeBuilder &builder);
151
152  /// Called by CoreEngine when processing the entrance of a CFGBlock.
153  virtual void processCFGBlockEntrance(ExplodedNodeSet &dstNodes,
154                                GenericNodeBuilder<BlockEntrance> &nodeBuilder);
155
156  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
157  ///  nodes by processing the 'effects' of a branch condition.
158  void processBranch(const Stmt* Condition, const Stmt* Term,
159                     BranchNodeBuilder& builder);
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 GRState *processAssume(const GRState *state, SVal cond,bool assumption);
185
186  /// wantsRegionChangeUpdate - Called by GRStateManager to determine if a
187  ///  region change should trigger a processRegionChanges update.
188  bool wantsRegionChangeUpdate(const GRState* state);
189
190  /// processRegionChanges - Called by GRStateManager whenever a change is made
191  ///  to the store. Used to update checkers that track region values.
192  const GRState *
193  processRegionChanges(const GRState *state,
194                       const StoreManager::InvalidatedSymbols *invalidated,
195                       const MemRegion * const *Begin,
196                       const MemRegion * const *End);
197
198  virtual GRStateManager& getStateManager() { return StateMgr; }
199
200  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
201
202  ConstraintManager& getConstraintManager() {
203    return StateMgr.getConstraintManager();
204  }
205
206  // FIXME: Remove when we migrate over to just using SValBuilder.
207  BasicValueFactory& getBasicVals() {
208    return StateMgr.getBasicVals();
209  }
210  const BasicValueFactory& getBasicVals() const {
211    return StateMgr.getBasicVals();
212  }
213
214  // FIXME: Remove when we migrate over to just using ValueManager.
215  SymbolManager& getSymbolManager() { return SymMgr; }
216  const SymbolManager& getSymbolManager() const { return SymMgr; }
217
218  // Functions for external checking of whether we have unfinished work
219  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
220  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
221  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
222
223  const CoreEngine &getCoreEngine() const { return Engine; }
224
225protected:
226  const GRState* GetState(ExplodedNode* N) {
227    return N == EntryNode ? CleanedState : N->getState();
228  }
229
230public:
231  ExplodedNode* MakeNode(ExplodedNodeSet& Dst, const Stmt* S,
232                         ExplodedNode* Pred, const GRState* St,
233                         ProgramPoint::Kind K = ProgramPoint::PostStmtKind,
234                         const void *tag = 0);
235
236  /// Visit - Transfer function logic for all statements.  Dispatches to
237  ///  other functions that handle specific kinds of statements.
238  void Visit(const Stmt* S, ExplodedNode* Pred, ExplodedNodeSet& Dst);
239
240  /// VisitArraySubscriptExpr - Transfer function for array accesses.
241  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr* Ex,
242                                   ExplodedNode* Pred,
243                                   ExplodedNodeSet& Dst);
244
245  /// VisitAsmStmt - Transfer function logic for inline asm.
246  void VisitAsmStmt(const AsmStmt* A, ExplodedNode* Pred, ExplodedNodeSet& Dst);
247
248  void VisitAsmStmtHelperOutputs(const AsmStmt* A,
249                                 AsmStmt::const_outputs_iterator I,
250                                 AsmStmt::const_outputs_iterator E,
251                                 ExplodedNode* Pred, ExplodedNodeSet& Dst);
252
253  void VisitAsmStmtHelperInputs(const AsmStmt* A,
254                                AsmStmt::const_inputs_iterator I,
255                                AsmStmt::const_inputs_iterator E,
256                                ExplodedNode* Pred, ExplodedNodeSet& Dst);
257
258  /// VisitBlockExpr - Transfer function logic for BlockExprs.
259  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
260                      ExplodedNodeSet &Dst);
261
262  /// VisitBinaryOperator - Transfer function logic for binary operators.
263  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode* Pred,
264                           ExplodedNodeSet& Dst);
265
266
267  /// VisitCall - Transfer function for function calls.
268  void VisitCallExpr(const CallExpr* CE, ExplodedNode* Pred,
269                     ExplodedNodeSet& Dst);
270
271  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
272  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
273                ExplodedNodeSet &Dst);
274
275  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
276  void VisitCompoundLiteralExpr(const CompoundLiteralExpr* CL,
277                                ExplodedNode* Pred, ExplodedNodeSet& Dst);
278
279  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
280  void VisitCommonDeclRefExpr(const Expr* DR, const NamedDecl *D,
281                              ExplodedNode* Pred, ExplodedNodeSet& Dst);
282
283  /// VisitDeclStmt - Transfer function logic for DeclStmts.
284  void VisitDeclStmt(const DeclStmt* DS, ExplodedNode* Pred,
285                     ExplodedNodeSet& Dst);
286
287  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
288  void VisitGuardedExpr(const Expr* Ex, const Expr* L, const Expr* R,
289                        ExplodedNode* Pred, ExplodedNodeSet& Dst);
290
291  void VisitInitListExpr(const InitListExpr* E, ExplodedNode* Pred,
292                         ExplodedNodeSet& Dst);
293
294  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
295  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode* Pred,
296                        ExplodedNodeSet& Dst);
297
298  /// VisitMemberExpr - Transfer function for member expressions.
299  void VisitMemberExpr(const MemberExpr* M, ExplodedNode* Pred,
300                           ExplodedNodeSet& Dst);
301
302  /// Transfer function logic for ObjCAtSynchronizedStmts.
303  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
304                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
305
306  void VisitObjCPropertyRefExpr(const ObjCPropertyRefExpr *E,
307                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
308
309  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
310  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr* DR, ExplodedNode* Pred,
311                                ExplodedNodeSet& Dst);
312
313  /// VisitObjCForCollectionStmt - Transfer function logic for
314  ///  ObjCForCollectionStmt.
315  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt* S,
316                                  ExplodedNode* Pred, ExplodedNodeSet& Dst);
317
318  void VisitObjCForCollectionStmtAux(const ObjCForCollectionStmt* S,
319                                     ExplodedNode* Pred,
320                                     ExplodedNodeSet& Dst, SVal ElementV);
321
322  /// VisitObjCMessageExpr - Transfer function for ObjC message expressions.
323  void VisitObjCMessageExpr(const ObjCMessageExpr* ME, ExplodedNode* Pred,
324                            ExplodedNodeSet& Dst);
325  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNodeSet &Src,
326                        ExplodedNodeSet& Dst);
327
328  /// VisitReturnStmt - Transfer function logic for return statements.
329  void VisitReturnStmt(const ReturnStmt* R, ExplodedNode* Pred,
330                       ExplodedNodeSet& Dst);
331
332  /// VisitOffsetOfExpr - Transfer function for offsetof.
333  void VisitOffsetOfExpr(const OffsetOfExpr* Ex, ExplodedNode* Pred,
334                         ExplodedNodeSet& Dst);
335
336  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
337  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr* Ex,
338                              ExplodedNode* Pred, ExplodedNodeSet& Dst);
339
340  /// VisitUnaryOperator - Transfer function logic for unary operators.
341  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode* Pred,
342                          ExplodedNodeSet& Dst);
343
344  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
345                        ExplodedNodeSet & Dst);
346
347  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
348                                   ExplodedNode *Pred, ExplodedNodeSet &Dst) {
349    VisitCXXConstructExpr(expr, 0, Pred, Dst);
350  }
351
352  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
353                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
354
355  void VisitCXXDestructor(const CXXDestructorDecl *DD,
356                          const MemRegion *Dest, const Stmt *S,
357                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
358
359  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
360                       ExplodedNodeSet &Dst);
361
362  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
363                          ExplodedNodeSet &Dst);
364
365  void VisitAggExpr(const Expr *E, const MemRegion *Dest, ExplodedNode *Pred,
366                    ExplodedNodeSet &Dst);
367
368  /// Create a C++ temporary object for an rvalue.
369  void CreateCXXTemporaryObject(const Expr *Ex, ExplodedNode *Pred,
370                                ExplodedNodeSet &Dst);
371
372  /// Synthesize CXXThisRegion.
373  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
374                                        const StackFrameContext *SFC);
375
376  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
377                                        const StackFrameContext *frameCtx);
378
379  /// Evaluate arguments with a work list algorithm.
380  void evalArguments(ConstExprIterator AI, ConstExprIterator AE,
381                     const FunctionProtoType *FnType,
382                     ExplodedNode *Pred, ExplodedNodeSet &Dst,
383                     bool FstArgAsLValue = false);
384
385  /// Evaluate callee expression (for a function call).
386  void evalCallee(const CallExpr *callExpr, const ExplodedNodeSet &src,
387                  ExplodedNodeSet &dest);
388
389  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
390  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
391  ///  with those assumptions.
392  void evalEagerlyAssume(ExplodedNodeSet& Dst, ExplodedNodeSet& Src,
393                         const Expr *Ex);
394
395  SVal evalMinus(SVal X) {
396    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
397  }
398
399  SVal evalComplement(SVal X) {
400    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
401  }
402
403public:
404
405  SVal evalBinOp(const GRState *state, BinaryOperator::Opcode op,
406                 NonLoc L, NonLoc R, QualType T) {
407    return svalBuilder.evalBinOpNN(state, op, L, R, T);
408  }
409
410  SVal evalBinOp(const GRState *state, BinaryOperator::Opcode op,
411                 NonLoc L, SVal R, QualType T) {
412    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
413  }
414
415  SVal evalBinOp(const GRState *ST, BinaryOperator::Opcode Op,
416                 SVal LHS, SVal RHS, QualType T) {
417    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
418  }
419
420protected:
421  void evalObjCMessage(ExplodedNodeSet& Dst, const ObjCMessage &msg,
422                       ExplodedNode* Pred, const GRState *state) {
423    assert (Builder && "StmtNodeBuilder must be defined.");
424    getTF().evalObjCMessage(Dst, *this, *Builder, msg, Pred, state);
425  }
426
427  const GRState* MarkBranch(const GRState* St, const Stmt* Terminator,
428                            bool branchTaken);
429
430  /// evalBind - Handle the semantics of binding a value to a specific location.
431  ///  This method is used by evalStore, VisitDeclStmt, and others.
432  void evalBind(ExplodedNodeSet& Dst, const Stmt* StoreE, ExplodedNode* Pred,
433                const GRState* St, SVal location, SVal Val,
434                bool atDeclInit = false);
435
436public:
437  // FIXME: 'tag' should be removed, and a LocationContext should be used
438  // instead.
439  // FIXME: Comment on the meaning of the arguments, when 'St' may not
440  // be the same as Pred->state, and when 'location' may not be the
441  // same as state->getLValue(Ex).
442  /// Simulate a read of the result of Ex.
443  void evalLoad(ExplodedNodeSet& Dst, const Expr* Ex, ExplodedNode* Pred,
444                const GRState* St, SVal location, const void *tag = 0,
445                QualType LoadTy = QualType());
446
447  // FIXME: 'tag' should be removed, and a LocationContext should be used
448  // instead.
449  void evalStore(ExplodedNodeSet& Dst, const Expr* AssignE, const Expr* StoreE,
450                 ExplodedNode* Pred, const GRState* St, SVal TargetLV, SVal Val,
451                 const void *tag = 0);
452private:
453  void evalLoadCommon(ExplodedNodeSet& Dst, const Expr* Ex, ExplodedNode* Pred,
454                      const GRState* St, SVal location, const void *tag,
455                      QualType LoadTy);
456
457  // FIXME: 'tag' should be removed, and a LocationContext should be used
458  // instead.
459  void evalLocation(ExplodedNodeSet &Dst, const Stmt *S, ExplodedNode* Pred,
460                    const GRState* St, SVal location,
461                    const void *tag, bool isLoad);
462
463  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
464
465
466public:
467  /// Returns true if calling the specific function or method would possibly
468  /// cause global variables to be invalidated.
469  bool doesInvalidateGlobals(const CallOrObjCMessage &callOrMessage) const;
470
471};
472
473} // end ento namespace
474
475} // end clang namespace
476
477#endif
478