ExprEngine.h revision 253955ca25c7e7049963b5db613c0cd15d66e4f8 
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, SetOfDecls *VisitedCallees);
95
96  ~ExprEngine();
97
98  /// Returns true if there is still simulation state on the worklist.
99  bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
100    return Engine.ExecuteWorkList(L, Steps, 0);
101  }
102
103  /// Execute the work list with an initial state. Nodes that reaches the exit
104  /// of the function are added into the Dst set, which represent the exit
105  /// state of the function call. Returns true if there is still simulation
106  /// state on the worklist.
107  bool ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps,
108                                       ProgramStateRef InitState,
109                                       ExplodedNodeSet &Dst) {
110    return Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst);
111  }
112
113  /// getContext - Return the ASTContext associated with this analysis.
114  ASTContext &getContext() const { return AMgr.getASTContext(); }
115
116  virtual AnalysisManager &getAnalysisManager() { return AMgr; }
117
118  CheckerManager &getCheckerManager() const {
119    return *AMgr.getCheckerManager();
120  }
121
122  SValBuilder &getSValBuilder() { return svalBuilder; }
123
124  BugReporter& getBugReporter() { return BR; }
125
126  const NodeBuilderContext &getBuilderContext() {
127    assert(currentBuilderContext);
128    return *currentBuilderContext;
129  }
130
131  bool isObjCGCEnabled() { return ObjCGCEnabled; }
132
133  const Stmt *getStmt() const;
134
135  void GenerateAutoTransition(ExplodedNode *N);
136  void enqueueEndOfPath(ExplodedNodeSet &S);
137  void GenerateCallExitNode(ExplodedNode *N);
138
139  /// ViewGraph - Visualize the ExplodedGraph created by executing the
140  ///  simulation.
141  void ViewGraph(bool trim = false);
142
143  void ViewGraph(ExplodedNode** Beg, ExplodedNode** End);
144
145  /// getInitialState - Return the initial state used for the root vertex
146  ///  in the ExplodedGraph.
147  ProgramStateRef getInitialState(const LocationContext *InitLoc);
148
149  ExplodedGraph& getGraph() { return G; }
150  const ExplodedGraph& getGraph() const { return G; }
151
152  /// processCFGElement - Called by CoreEngine. Used to generate new successor
153  ///  nodes by processing the 'effects' of a CFG element.
154  void processCFGElement(const CFGElement E, ExplodedNode *Pred,
155                         unsigned StmtIdx, NodeBuilderContext *Ctx);
156
157  void ProcessStmt(const CFGStmt S, ExplodedNode *Pred);
158
159  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);
160
161  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);
162
163  void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D,
164                               ExplodedNode *Pred, ExplodedNodeSet &Dst);
165  void ProcessBaseDtor(const CFGBaseDtor D,
166                       ExplodedNode *Pred, ExplodedNodeSet &Dst);
167  void ProcessMemberDtor(const CFGMemberDtor D,
168                         ExplodedNode *Pred, ExplodedNodeSet &Dst);
169  void ProcessTemporaryDtor(const CFGTemporaryDtor D,
170                            ExplodedNode *Pred, ExplodedNodeSet &Dst);
171
172  /// Called by CoreEngine when processing the entrance of a CFGBlock.
173  virtual void processCFGBlockEntrance(const BlockEdge &L,
174                                       NodeBuilderWithSinks &nodeBuilder);
175
176  /// ProcessBranch - Called by CoreEngine.  Used to generate successor
177  ///  nodes by processing the 'effects' of a branch condition.
178  void processBranch(const Stmt *Condition, const Stmt *Term,
179                     NodeBuilderContext& BuilderCtx,
180                     ExplodedNode *Pred,
181                     ExplodedNodeSet &Dst,
182                     const CFGBlock *DstT,
183                     const CFGBlock *DstF);
184
185  /// processIndirectGoto - Called by CoreEngine.  Used to generate successor
186  ///  nodes by processing the 'effects' of a computed goto jump.
187  void processIndirectGoto(IndirectGotoNodeBuilder& builder);
188
189  /// ProcessSwitch - Called by CoreEngine.  Used to generate successor
190  ///  nodes by processing the 'effects' of a switch statement.
191  void processSwitch(SwitchNodeBuilder& builder);
192
193  /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
194  ///  nodes when the control reaches the end of a function.
195  void processEndOfFunction(NodeBuilderContext& BC);
196
197  /// Generate the entry node of the callee.
198  void processCallEnter(CallEnter CE, ExplodedNode *Pred);
199
200  /// Generate the first post callsite node.
201  void processCallExit(ExplodedNode *Pred);
202
203  /// Called by CoreEngine when the analysis worklist has terminated.
204  void processEndWorklist(bool hasWorkRemaining);
205
206  /// evalAssume - Callback function invoked by the ConstraintManager when
207  ///  making assumptions about state values.
208  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption);
209
210  /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a
211  ///  region change should trigger a processRegionChanges update.
212  bool wantsRegionChangeUpdate(ProgramStateRef state);
213
214  /// processRegionChanges - Called by ProgramStateManager whenever a change is made
215  ///  to the store. Used to update checkers that track region values.
216  ProgramStateRef
217  processRegionChanges(ProgramStateRef state,
218                       const StoreManager::InvalidatedSymbols *invalidated,
219                       ArrayRef<const MemRegion *> ExplicitRegions,
220                       ArrayRef<const MemRegion *> Regions,
221                       const CallOrObjCMessage *Call);
222
223  /// printState - Called by ProgramStateManager to print checker-specific data.
224  void printState(raw_ostream &Out, ProgramStateRef State,
225                  const char *NL, const char *Sep);
226
227  virtual ProgramStateManager& getStateManager() { return StateMgr; }
228
229  StoreManager& getStoreManager() { return StateMgr.getStoreManager(); }
230
231  ConstraintManager& getConstraintManager() {
232    return StateMgr.getConstraintManager();
233  }
234
235  // FIXME: Remove when we migrate over to just using SValBuilder.
236  BasicValueFactory& getBasicVals() {
237    return StateMgr.getBasicVals();
238  }
239  const BasicValueFactory& getBasicVals() const {
240    return StateMgr.getBasicVals();
241  }
242
243  // FIXME: Remove when we migrate over to just using ValueManager.
244  SymbolManager& getSymbolManager() { return SymMgr; }
245  const SymbolManager& getSymbolManager() const { return SymMgr; }
246
247  // Functions for external checking of whether we have unfinished work
248  bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); }
249  bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); }
250  bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); }
251
252  const CoreEngine &getCoreEngine() const { return Engine; }
253
254public:
255  /// Visit - Transfer function logic for all statements.  Dispatches to
256  ///  other functions that handle specific kinds of statements.
257  void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst);
258
259  /// VisitArraySubscriptExpr - Transfer function for array accesses.
260  void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex,
261                                   ExplodedNode *Pred,
262                                   ExplodedNodeSet &Dst);
263
264  /// VisitAsmStmt - Transfer function logic for inline asm.
265  void VisitAsmStmt(const AsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst);
266
267  /// VisitBlockExpr - Transfer function logic for BlockExprs.
268  void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
269                      ExplodedNodeSet &Dst);
270
271  /// VisitBinaryOperator - Transfer function logic for binary operators.
272  void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred,
273                           ExplodedNodeSet &Dst);
274
275
276  /// VisitCall - Transfer function for function calls.
277  void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
278                     ExplodedNodeSet &Dst);
279
280  /// VisitCast - Transfer function logic for all casts (implicit and explicit).
281  void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred,
282                ExplodedNodeSet &Dst);
283
284  /// VisitCompoundLiteralExpr - Transfer function logic for compound literals.
285  void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
286                                ExplodedNode *Pred, ExplodedNodeSet &Dst);
287
288  /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs.
289  void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D,
290                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
291
292  /// VisitDeclStmt - Transfer function logic for DeclStmts.
293  void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
294                     ExplodedNodeSet &Dst);
295
296  /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose
297  void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R,
298                        ExplodedNode *Pred, ExplodedNodeSet &Dst);
299
300  void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred,
301                         ExplodedNodeSet &Dst);
302
303  /// VisitLogicalExpr - Transfer function logic for '&&', '||'
304  void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
305                        ExplodedNodeSet &Dst);
306
307  /// VisitMemberExpr - Transfer function for member expressions.
308  void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
309                           ExplodedNodeSet &Dst);
310
311  /// Transfer function logic for ObjCAtSynchronizedStmts.
312  void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S,
313                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
314
315  /// Transfer function logic for computing the lvalue of an Objective-C ivar.
316  void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred,
317                                ExplodedNodeSet &Dst);
318
319  /// VisitObjCForCollectionStmt - Transfer function logic for
320  ///  ObjCForCollectionStmt.
321  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S,
322                                  ExplodedNode *Pred, ExplodedNodeSet &Dst);
323
324  void VisitObjCMessage(const ObjCMessage &msg, ExplodedNode *Pred,
325                        ExplodedNodeSet &Dst);
326
327  /// VisitReturnStmt - Transfer function logic for return statements.
328  void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred,
329                       ExplodedNodeSet &Dst);
330
331  /// VisitOffsetOfExpr - Transfer function for offsetof.
332  void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred,
333                         ExplodedNodeSet &Dst);
334
335  /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof.
336  void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
337                              ExplodedNode *Pred, ExplodedNodeSet &Dst);
338
339  /// VisitUnaryOperator - Transfer function logic for unary operators.
340  void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred,
341                          ExplodedNodeSet &Dst);
342
343  /// Handle ++ and -- (both pre- and post-increment).
344  void VisitIncrementDecrementOperator(const UnaryOperator* U,
345                                       ExplodedNode *Pred,
346                                       ExplodedNodeSet &Dst);
347
348  void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,
349                         ExplodedNodeSet &Dst);
350
351  void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
352                        ExplodedNodeSet & Dst);
353
354  void VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr,
355                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
356
357  void VisitCXXConstructExpr(const CXXConstructExpr *E, const MemRegion *Dest,
358                             ExplodedNode *Pred, ExplodedNodeSet &Dst);
359
360  void VisitCXXDestructor(const CXXDestructorDecl *DD,
361                          const MemRegion *Dest, const Stmt *S,
362                          ExplodedNode *Pred, ExplodedNodeSet &Dst);
363
364  void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
365                       ExplodedNodeSet &Dst);
366
367  void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred,
368                          ExplodedNodeSet &Dst);
369
370  /// Create a C++ temporary object for an rvalue.
371  void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
372                                ExplodedNode *Pred,
373                                ExplodedNodeSet &Dst);
374
375  /// Synthesize CXXThisRegion.
376  const CXXThisRegion *getCXXThisRegion(const CXXRecordDecl *RD,
377                                        const StackFrameContext *SFC);
378
379  const CXXThisRegion *getCXXThisRegion(const CXXMethodDecl *decl,
380                                        const StackFrameContext *frameCtx);
381
382  /// evalEagerlyAssume - Given the nodes in 'Src', eagerly assume symbolic
383  ///  expressions of the form 'x != 0' and generate new nodes (stored in Dst)
384  ///  with those assumptions.
385  void evalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
386                         const Expr *Ex);
387
388  std::pair<const ProgramPointTag *, const ProgramPointTag*>
389    getEagerlyAssumeTags();
390
391  SVal evalMinus(SVal X) {
392    return X.isValid() ? svalBuilder.evalMinus(cast<NonLoc>(X)) : X;
393  }
394
395  SVal evalComplement(SVal X) {
396    return X.isValid() ? svalBuilder.evalComplement(cast<NonLoc>(X)) : X;
397  }
398
399public:
400
401  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
402                 NonLoc L, NonLoc R, QualType T) {
403    return svalBuilder.evalBinOpNN(state, op, L, R, T);
404  }
405
406  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
407                 NonLoc L, SVal R, QualType T) {
408    return R.isValid() ? svalBuilder.evalBinOpNN(state,op,L, cast<NonLoc>(R), T) : R;
409  }
410
411  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
412                 SVal LHS, SVal RHS, QualType T) {
413    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
414  }
415
416protected:
417  void evalObjCMessage(StmtNodeBuilder &Bldr, const ObjCMessage &msg,
418                       ExplodedNode *Pred, ProgramStateRef state,
419                       bool GenSink);
420
421  ProgramStateRef invalidateArguments(ProgramStateRef State,
422                                          const CallOrObjCMessage &Call,
423                                          const LocationContext *LC);
424
425  ProgramStateRef MarkBranch(ProgramStateRef state,
426                                 const Stmt *Terminator,
427                                 const LocationContext *LCtx,
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                SVal location, SVal Val, bool atDeclInit = false);
434
435public:
436  // FIXME: 'tag' should be removed, and a LocationContext should be used
437  // instead.
438  // FIXME: Comment on the meaning of the arguments, when 'St' may not
439  // be the same as Pred->state, and when 'location' may not be the
440  // same as state->getLValue(Ex).
441  /// Simulate a read of the result of Ex.
442  void evalLoad(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
443                ProgramStateRef St, SVal location, const ProgramPointTag *tag = 0,
444                QualType LoadTy = QualType());
445
446  // FIXME: 'tag' should be removed, and a LocationContext should be used
447  // instead.
448  void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE,
449                 ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val,
450                 const ProgramPointTag *tag = 0);
451private:
452  void evalLoadCommon(ExplodedNodeSet &Dst, const Expr *Ex, ExplodedNode *Pred,
453                      ProgramStateRef St, SVal location, const ProgramPointTag *tag,
454                      QualType LoadTy);
455
456  // FIXME: 'tag' should be removed, and a LocationContext should be used
457  // instead.
458  void evalLocation(ExplodedNodeSet &Dst, const Stmt *S, ExplodedNode *Pred,
459                    ProgramStateRef St, SVal location,
460                    const ProgramPointTag *tag, bool isLoad);
461
462  bool shouldInlineDecl(const FunctionDecl *FD, ExplodedNode *Pred);
463  bool InlineCall(ExplodedNodeSet &Dst, const CallExpr *CE, ExplodedNode *Pred);
464
465  bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC);
466};
467
468/// Traits for storing the call processing policy inside GDM.
469/// The GDM stores the corresponding CallExpr pointer.
470struct ReplayWithoutInlining{};
471template <>
472struct ProgramStateTrait<ReplayWithoutInlining> :
473  public ProgramStatePartialTrait<void*> {
474  static void *GDMIndex() { static int index = 0; return &index; }
475};
476
477} // end ento namespace
478
479} // end clang namespace
480
481#endif
482