CoreEngine.cpp revision 9c378f705405d37f49795d5e915989de774fe11f 
1//==- CoreEngine.cpp - Path-Sensitive Dataflow Engine ------------*- 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 generic engine for intraprocedural, path-sensitive,
11//  dataflow analysis via graph reachability engine.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
16#include "clang/StaticAnalyzer/Core/PathSensitive/CoreEngine.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
18#include "clang/Index/TranslationUnit.h"
19#include "clang/AST/Expr.h"
20#include "llvm/Support/Casting.h"
21#include "llvm/ADT/DenseMap.h"
22using namespace clang;
23using namespace ento;
24
25// This should be removed in the future.
26namespace clang {
27namespace ento {
28TransferFuncs* MakeCFRefCountTF(ASTContext &Ctx, bool GCEnabled,
29                                  const LangOptions& lopts);
30}
31}
32
33//===----------------------------------------------------------------------===//
34// Worklist classes for exploration of reachable states.
35//===----------------------------------------------------------------------===//
36
37WorkList::Visitor::~Visitor() {}
38
39namespace {
40class DFS : public WorkList {
41  SmallVector<WorkListUnit,20> Stack;
42public:
43  virtual bool hasWork() const {
44    return !Stack.empty();
45  }
46
47  virtual void enqueue(const WorkListUnit& U) {
48    Stack.push_back(U);
49  }
50
51  virtual WorkListUnit dequeue() {
52    assert (!Stack.empty());
53    const WorkListUnit& U = Stack.back();
54    Stack.pop_back(); // This technically "invalidates" U, but we are fine.
55    return U;
56  }
57
58  virtual bool visitItemsInWorkList(Visitor &V) {
59    for (SmallVectorImpl<WorkListUnit>::iterator
60         I = Stack.begin(), E = Stack.end(); I != E; ++I) {
61      if (V.visit(*I))
62        return true;
63    }
64    return false;
65  }
66};
67
68class BFS : public WorkList {
69  std::deque<WorkListUnit> Queue;
70public:
71  virtual bool hasWork() const {
72    return !Queue.empty();
73  }
74
75  virtual void enqueue(const WorkListUnit& U) {
76    Queue.push_front(U);
77  }
78
79  virtual WorkListUnit dequeue() {
80    WorkListUnit U = Queue.front();
81    Queue.pop_front();
82    return U;
83  }
84
85  virtual bool visitItemsInWorkList(Visitor &V) {
86    for (std::deque<WorkListUnit>::iterator
87         I = Queue.begin(), E = Queue.end(); I != E; ++I) {
88      if (V.visit(*I))
89        return true;
90    }
91    return false;
92  }
93};
94
95} // end anonymous namespace
96
97// Place the dstor for WorkList here because it contains virtual member
98// functions, and we the code for the dstor generated in one compilation unit.
99WorkList::~WorkList() {}
100
101WorkList *WorkList::makeDFS() { return new DFS(); }
102WorkList *WorkList::makeBFS() { return new BFS(); }
103
104namespace {
105  class BFSBlockDFSContents : public WorkList {
106    std::deque<WorkListUnit> Queue;
107    SmallVector<WorkListUnit,20> Stack;
108  public:
109    virtual bool hasWork() const {
110      return !Queue.empty() || !Stack.empty();
111    }
112
113    virtual void enqueue(const WorkListUnit& U) {
114      if (isa<BlockEntrance>(U.getNode()->getLocation()))
115        Queue.push_front(U);
116      else
117        Stack.push_back(U);
118    }
119
120    virtual WorkListUnit dequeue() {
121      // Process all basic blocks to completion.
122      if (!Stack.empty()) {
123        const WorkListUnit& U = Stack.back();
124        Stack.pop_back(); // This technically "invalidates" U, but we are fine.
125        return U;
126      }
127
128      assert(!Queue.empty());
129      // Don't use const reference.  The subsequent pop_back() might make it
130      // unsafe.
131      WorkListUnit U = Queue.front();
132      Queue.pop_front();
133      return U;
134    }
135    virtual bool visitItemsInWorkList(Visitor &V) {
136      for (SmallVectorImpl<WorkListUnit>::iterator
137           I = Stack.begin(), E = Stack.end(); I != E; ++I) {
138        if (V.visit(*I))
139          return true;
140      }
141      for (std::deque<WorkListUnit>::iterator
142           I = Queue.begin(), E = Queue.end(); I != E; ++I) {
143        if (V.visit(*I))
144          return true;
145      }
146      return false;
147    }
148
149  };
150} // end anonymous namespace
151
152WorkList* WorkList::makeBFSBlockDFSContents() {
153  return new BFSBlockDFSContents();
154}
155
156//===----------------------------------------------------------------------===//
157// Core analysis engine.
158//===----------------------------------------------------------------------===//
159
160/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
161bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
162                                   const GRState *InitState) {
163
164  if (G->num_roots() == 0) { // Initialize the analysis by constructing
165    // the root if none exists.
166
167    const CFGBlock *Entry = &(L->getCFG()->getEntry());
168
169    assert (Entry->empty() &&
170            "Entry block must be empty.");
171
172    assert (Entry->succ_size() == 1 &&
173            "Entry block must have 1 successor.");
174
175    // Get the solitary successor.
176    const CFGBlock *Succ = *(Entry->succ_begin());
177
178    // Construct an edge representing the
179    // starting location in the function.
180    BlockEdge StartLoc(Entry, Succ, L);
181
182    // Set the current block counter to being empty.
183    WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
184
185    if (!InitState)
186      // Generate the root.
187      generateNode(StartLoc, SubEng.getInitialState(L), 0);
188    else
189      generateNode(StartLoc, InitState, 0);
190  }
191
192  // Check if we have a steps limit
193  bool UnlimitedSteps = Steps == 0;
194
195  while (WList->hasWork()) {
196    if (!UnlimitedSteps) {
197      if (Steps == 0)
198        break;
199      --Steps;
200    }
201
202    const WorkListUnit& WU = WList->dequeue();
203
204    // Set the current block counter.
205    WList->setBlockCounter(WU.getBlockCounter());
206
207    // Retrieve the node.
208    ExplodedNode *Node = WU.getNode();
209
210    // Dispatch on the location type.
211    switch (Node->getLocation().getKind()) {
212      case ProgramPoint::BlockEdgeKind:
213        HandleBlockEdge(cast<BlockEdge>(Node->getLocation()), Node);
214        break;
215
216      case ProgramPoint::BlockEntranceKind:
217        HandleBlockEntrance(cast<BlockEntrance>(Node->getLocation()), Node);
218        break;
219
220      case ProgramPoint::BlockExitKind:
221        assert (false && "BlockExit location never occur in forward analysis.");
222        break;
223
224      case ProgramPoint::CallEnterKind:
225        HandleCallEnter(cast<CallEnter>(Node->getLocation()), WU.getBlock(),
226                        WU.getIndex(), Node);
227        break;
228
229      case ProgramPoint::CallExitKind:
230        HandleCallExit(cast<CallExit>(Node->getLocation()), Node);
231        break;
232
233      default:
234        assert(isa<PostStmt>(Node->getLocation()) ||
235               isa<PostInitializer>(Node->getLocation()));
236        HandlePostStmt(WU.getBlock(), WU.getIndex(), Node);
237        break;
238    }
239  }
240
241  SubEng.processEndWorklist(hasWorkRemaining());
242  return WList->hasWork();
243}
244
245void CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
246                                                   unsigned Steps,
247                                                   const GRState *InitState,
248                                                   ExplodedNodeSet &Dst) {
249  ExecuteWorkList(L, Steps, InitState);
250  for (SmallVectorImpl<ExplodedNode*>::iterator I = G->EndNodes.begin(),
251                                           E = G->EndNodes.end(); I != E; ++I) {
252    Dst.Add(*I);
253  }
254}
255
256void CoreEngine::HandleCallEnter(const CallEnter &L, const CFGBlock *Block,
257                                   unsigned Index, ExplodedNode *Pred) {
258  CallEnterNodeBuilder Builder(*this, Pred, L.getCallExpr(),
259                                 L.getCalleeContext(), Block, Index);
260  SubEng.processCallEnter(Builder);
261}
262
263void CoreEngine::HandleCallExit(const CallExit &L, ExplodedNode *Pred) {
264  CallExitNodeBuilder Builder(*this, Pred);
265  SubEng.processCallExit(Builder);
266}
267
268void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
269
270  const CFGBlock *Blk = L.getDst();
271
272  // Check if we are entering the EXIT block.
273  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
274
275    assert (L.getLocationContext()->getCFG()->getExit().size() == 0
276            && "EXIT block cannot contain Stmts.");
277
278    // Process the final state transition.
279    EndOfFunctionNodeBuilder Builder(Blk, Pred, this);
280    SubEng.processEndOfFunction(Builder);
281
282    // This path is done. Don't enqueue any more nodes.
283    return;
284  }
285
286  // Call into the subengine to process entering the CFGBlock.
287  ExplodedNodeSet dstNodes;
288  BlockEntrance BE(Blk, Pred->getLocationContext());
289  GenericNodeBuilder<BlockEntrance> nodeBuilder(*this, Pred, BE);
290  SubEng.processCFGBlockEntrance(dstNodes, nodeBuilder);
291
292  if (dstNodes.empty()) {
293    if (!nodeBuilder.hasGeneratedNode) {
294      // Auto-generate a node and enqueue it to the worklist.
295      generateNode(BE, Pred->State, Pred);
296    }
297  }
298  else {
299    for (ExplodedNodeSet::iterator I = dstNodes.begin(), E = dstNodes.end();
300         I != E; ++I) {
301      WList->enqueue(*I);
302    }
303  }
304
305  for (SmallVectorImpl<ExplodedNode*>::const_iterator
306       I = nodeBuilder.sinks().begin(), E = nodeBuilder.sinks().end();
307       I != E; ++I) {
308    blocksExhausted.push_back(std::make_pair(L, *I));
309  }
310}
311
312void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
313                                       ExplodedNode *Pred) {
314
315  // Increment the block counter.
316  BlockCounter Counter = WList->getBlockCounter();
317  Counter = BCounterFactory.IncrementCount(Counter,
318                             Pred->getLocationContext()->getCurrentStackFrame(),
319                                           L.getBlock()->getBlockID());
320  WList->setBlockCounter(Counter);
321
322  // Process the entrance of the block.
323  if (CFGElement E = L.getFirstElement()) {
324    StmtNodeBuilder Builder(L.getBlock(), 0, Pred, this,
325                              SubEng.getStateManager());
326    SubEng.processCFGElement(E, Builder);
327  }
328  else
329    HandleBlockExit(L.getBlock(), Pred);
330}
331
332void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
333
334  if (const Stmt *Term = B->getTerminator()) {
335    switch (Term->getStmtClass()) {
336      default:
337        assert(false && "Analysis for this terminator not implemented.");
338        break;
339
340      case Stmt::BinaryOperatorClass: // '&&' and '||'
341        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
342        return;
343
344      case Stmt::BinaryConditionalOperatorClass:
345      case Stmt::ConditionalOperatorClass:
346        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
347                     Term, B, Pred);
348        return;
349
350        // FIXME: Use constant-folding in CFG construction to simplify this
351        // case.
352
353      case Stmt::ChooseExprClass:
354        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
355        return;
356
357      case Stmt::DoStmtClass:
358        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
359        return;
360
361      case Stmt::ForStmtClass:
362        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
363        return;
364
365      case Stmt::ContinueStmtClass:
366      case Stmt::BreakStmtClass:
367      case Stmt::GotoStmtClass:
368        break;
369
370      case Stmt::IfStmtClass:
371        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
372        return;
373
374      case Stmt::IndirectGotoStmtClass: {
375        // Only 1 successor: the indirect goto dispatch block.
376        assert (B->succ_size() == 1);
377
378        IndirectGotoNodeBuilder
379           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
380                   *(B->succ_begin()), this);
381
382        SubEng.processIndirectGoto(builder);
383        return;
384      }
385
386      case Stmt::ObjCForCollectionStmtClass: {
387        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
388        //
389        //  (1) inside a basic block, which represents the binding of the
390        //      'element' variable to a value.
391        //  (2) in a terminator, which represents the branch.
392        //
393        // For (1), subengines will bind a value (i.e., 0 or 1) indicating
394        // whether or not collection contains any more elements.  We cannot
395        // just test to see if the element is nil because a container can
396        // contain nil elements.
397        HandleBranch(Term, Term, B, Pred);
398        return;
399      }
400
401      case Stmt::SwitchStmtClass: {
402        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
403                                    this);
404
405        SubEng.processSwitch(builder);
406        return;
407      }
408
409      case Stmt::WhileStmtClass:
410        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
411        return;
412    }
413  }
414
415  assert (B->succ_size() == 1 &&
416          "Blocks with no terminator should have at most 1 successor.");
417
418  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
419               Pred->State, Pred);
420}
421
422void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
423                                const CFGBlock * B, ExplodedNode *Pred) {
424  assert(B->succ_size() == 2);
425  BranchNodeBuilder Builder(B, *(B->succ_begin()), *(B->succ_begin()+1),
426                            Pred, this);
427  SubEng.processBranch(Cond, Term, Builder);
428}
429
430void CoreEngine::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
431                                  ExplodedNode *Pred) {
432  assert (!B->empty());
433
434  if (StmtIdx == B->size())
435    HandleBlockExit(B, Pred);
436  else {
437    StmtNodeBuilder Builder(B, StmtIdx, Pred, this,
438                              SubEng.getStateManager());
439    SubEng.processCFGElement((*B)[StmtIdx], Builder);
440  }
441}
442
443/// generateNode - Utility method to generate nodes, hook up successors,
444///  and add nodes to the worklist.
445void CoreEngine::generateNode(const ProgramPoint &Loc,
446                              const GRState *State, ExplodedNode *Pred) {
447
448  bool IsNew;
449  ExplodedNode *Node = G->getNode(Loc, State, &IsNew);
450
451  if (Pred)
452    Node->addPredecessor(Pred, *G);  // Link 'Node' with its predecessor.
453  else {
454    assert (IsNew);
455    G->addRoot(Node);  // 'Node' has no predecessor.  Make it a root.
456  }
457
458  // Only add 'Node' to the worklist if it was freshly generated.
459  if (IsNew) WList->enqueue(Node);
460}
461
462ExplodedNode *
463GenericNodeBuilderImpl::generateNodeImpl(const GRState *state,
464                                         ExplodedNode *pred,
465                                         ProgramPoint programPoint,
466                                         bool asSink) {
467
468  hasGeneratedNode = true;
469  bool isNew;
470  ExplodedNode *node = engine.getGraph().getNode(programPoint, state, &isNew);
471  if (pred)
472    node->addPredecessor(pred, engine.getGraph());
473  if (isNew) {
474    if (asSink) {
475      node->markAsSink();
476      sinksGenerated.push_back(node);
477    }
478    return node;
479  }
480  return 0;
481}
482
483StmtNodeBuilder::StmtNodeBuilder(const CFGBlock *b, unsigned idx,
484                                     ExplodedNode *N, CoreEngine* e,
485                                     GRStateManager &mgr)
486  : Eng(*e), B(*b), Idx(idx), Pred(N), Mgr(mgr),
487    PurgingDeadSymbols(false), BuildSinks(false), hasGeneratedNode(false),
488    PointKind(ProgramPoint::PostStmtKind), Tag(0) {
489  Deferred.insert(N);
490}
491
492StmtNodeBuilder::~StmtNodeBuilder() {
493  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
494    if (!(*I)->isSink())
495      GenerateAutoTransition(*I);
496}
497
498void StmtNodeBuilder::GenerateAutoTransition(ExplodedNode *N) {
499  assert (!N->isSink());
500
501  // Check if this node entered a callee.
502  if (isa<CallEnter>(N->getLocation())) {
503    // Still use the index of the CallExpr. It's needed to create the callee
504    // StackFrameContext.
505    Eng.WList->enqueue(N, &B, Idx);
506    return;
507  }
508
509  // Do not create extra nodes. Move to the next CFG element.
510  if (isa<PostInitializer>(N->getLocation())) {
511    Eng.WList->enqueue(N, &B, Idx+1);
512    return;
513  }
514
515  PostStmt Loc(getStmt(), N->getLocationContext());
516
517  if (Loc == N->getLocation()) {
518    // Note: 'N' should be a fresh node because otherwise it shouldn't be
519    // a member of Deferred.
520    Eng.WList->enqueue(N, &B, Idx+1);
521    return;
522  }
523
524  bool IsNew;
525  ExplodedNode *Succ = Eng.G->getNode(Loc, N->State, &IsNew);
526  Succ->addPredecessor(N, *Eng.G);
527
528  if (IsNew)
529    Eng.WList->enqueue(Succ, &B, Idx+1);
530}
531
532ExplodedNode *StmtNodeBuilder::MakeNode(ExplodedNodeSet &Dst, const Stmt *S,
533                                          ExplodedNode *Pred, const GRState *St,
534                                          ProgramPoint::Kind K) {
535
536  ExplodedNode *N = generateNode(S, St, Pred, K);
537
538  if (N) {
539    if (BuildSinks)
540      N->markAsSink();
541    else
542      Dst.Add(N);
543  }
544
545  return N;
546}
547
548static ProgramPoint GetProgramPoint(const Stmt *S, ProgramPoint::Kind K,
549                                    const LocationContext *LC,
550                                    const ProgramPointTag *tag){
551  switch (K) {
552    default:
553      assert(false && "Unhandled ProgramPoint kind");
554    case ProgramPoint::PreStmtKind:
555      return PreStmt(S, LC, tag);
556    case ProgramPoint::PostStmtKind:
557      return PostStmt(S, LC, tag);
558    case ProgramPoint::PreLoadKind:
559      return PreLoad(S, LC, tag);
560    case ProgramPoint::PostLoadKind:
561      return PostLoad(S, LC, tag);
562    case ProgramPoint::PreStoreKind:
563      return PreStore(S, LC, tag);
564    case ProgramPoint::PostStoreKind:
565      return PostStore(S, LC, tag);
566    case ProgramPoint::PostLValueKind:
567      return PostLValue(S, LC, tag);
568    case ProgramPoint::PostPurgeDeadSymbolsKind:
569      return PostPurgeDeadSymbols(S, LC, tag);
570  }
571}
572
573ExplodedNode*
574StmtNodeBuilder::generateNodeInternal(const Stmt *S, const GRState *state,
575                                      ExplodedNode *Pred,
576                                      ProgramPoint::Kind K,
577                                      const ProgramPointTag *tag) {
578
579  const ProgramPoint &L = GetProgramPoint(S, K, Pred->getLocationContext(),
580                                          tag);
581  return generateNodeInternal(L, state, Pred);
582}
583
584ExplodedNode*
585StmtNodeBuilder::generateNodeInternal(const ProgramPoint &Loc,
586                                        const GRState *State,
587                                        ExplodedNode *Pred) {
588  bool IsNew;
589  ExplodedNode *N = Eng.G->getNode(Loc, State, &IsNew);
590  N->addPredecessor(Pred, *Eng.G);
591  Deferred.erase(Pred);
592
593  if (IsNew) {
594    Deferred.insert(N);
595    return N;
596  }
597
598  return NULL;
599}
600
601// This function generate a new ExplodedNode but not a new branch(block edge).
602ExplodedNode *BranchNodeBuilder::generateNode(const Stmt *Condition,
603                                              const GRState *State) {
604  bool IsNew;
605
606  ExplodedNode *Succ
607    = Eng.G->getNode(PostCondition(Condition, Pred->getLocationContext()), State,
608                     &IsNew);
609
610  Succ->addPredecessor(Pred, *Eng.G);
611
612  Pred = Succ;
613
614  if (IsNew)
615    return Succ;
616
617  return NULL;
618}
619
620ExplodedNode *BranchNodeBuilder::generateNode(const GRState *State,
621                                                bool branch) {
622
623  // If the branch has been marked infeasible we should not generate a node.
624  if (!isFeasible(branch))
625    return NULL;
626
627  bool IsNew;
628
629  ExplodedNode *Succ =
630    Eng.G->getNode(BlockEdge(Src,branch ? DstT:DstF,Pred->getLocationContext()),
631                   State, &IsNew);
632
633  Succ->addPredecessor(Pred, *Eng.G);
634
635  if (branch)
636    GeneratedTrue = true;
637  else
638    GeneratedFalse = true;
639
640  if (IsNew) {
641    Deferred.push_back(Succ);
642    return Succ;
643  }
644
645  return NULL;
646}
647
648BranchNodeBuilder::~BranchNodeBuilder() {
649  if (!GeneratedTrue) generateNode(Pred->State, true);
650  if (!GeneratedFalse) generateNode(Pred->State, false);
651
652  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
653    if (!(*I)->isSink()) Eng.WList->enqueue(*I);
654}
655
656
657ExplodedNode*
658IndirectGotoNodeBuilder::generateNode(const iterator &I, const GRState *St,
659                                        bool isSink) {
660  bool IsNew;
661
662  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
663                                      Pred->getLocationContext()), St, &IsNew);
664
665  Succ->addPredecessor(Pred, *Eng.G);
666
667  if (IsNew) {
668
669    if (isSink)
670      Succ->markAsSink();
671    else
672      Eng.WList->enqueue(Succ);
673
674    return Succ;
675  }
676
677  return NULL;
678}
679
680
681ExplodedNode*
682SwitchNodeBuilder::generateCaseStmtNode(const iterator &I, const GRState *St){
683
684  bool IsNew;
685
686  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
687                                       Pred->getLocationContext()), St, &IsNew);
688  Succ->addPredecessor(Pred, *Eng.G);
689
690  if (IsNew) {
691    Eng.WList->enqueue(Succ);
692    return Succ;
693  }
694
695  return NULL;
696}
697
698
699ExplodedNode*
700SwitchNodeBuilder::generateDefaultCaseNode(const GRState *St, bool isSink) {
701
702  // Get the block for the default case.
703  assert (Src->succ_rbegin() != Src->succ_rend());
704  CFGBlock *DefaultBlock = *Src->succ_rbegin();
705
706  bool IsNew;
707
708  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, DefaultBlock,
709                                       Pred->getLocationContext()), St, &IsNew);
710  Succ->addPredecessor(Pred, *Eng.G);
711
712  if (IsNew) {
713    if (isSink)
714      Succ->markAsSink();
715    else
716      Eng.WList->enqueue(Succ);
717
718    return Succ;
719  }
720
721  return NULL;
722}
723
724EndOfFunctionNodeBuilder::~EndOfFunctionNodeBuilder() {
725  // Auto-generate an EOP node if one has not been generated.
726  if (!hasGeneratedNode) {
727    // If we are in an inlined call, generate CallExit node.
728    if (Pred->getLocationContext()->getParent())
729      GenerateCallExitNode(Pred->State);
730    else
731      generateNode(Pred->State);
732  }
733}
734
735ExplodedNode*
736EndOfFunctionNodeBuilder::generateNode(const GRState *State,
737                                       ExplodedNode *P,
738                                       const ProgramPointTag *tag) {
739  hasGeneratedNode = true;
740  bool IsNew;
741
742  ExplodedNode *Node = Eng.G->getNode(BlockEntrance(&B,
743                               Pred->getLocationContext(), tag ? tag : Tag),
744                               State, &IsNew);
745
746  Node->addPredecessor(P ? P : Pred, *Eng.G);
747
748  if (IsNew) {
749    Eng.G->addEndOfPath(Node);
750    return Node;
751  }
752
753  return NULL;
754}
755
756void EndOfFunctionNodeBuilder::GenerateCallExitNode(const GRState *state) {
757  hasGeneratedNode = true;
758  // Create a CallExit node and enqueue it.
759  const StackFrameContext *LocCtx
760                         = cast<StackFrameContext>(Pred->getLocationContext());
761  const Stmt *CE = LocCtx->getCallSite();
762
763  // Use the the callee location context.
764  CallExit Loc(CE, LocCtx);
765
766  bool isNew;
767  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
768  Node->addPredecessor(Pred, *Eng.G);
769
770  if (isNew)
771    Eng.WList->enqueue(Node);
772}
773
774
775void CallEnterNodeBuilder::generateNode(const GRState *state) {
776  // Check if the callee is in the same translation unit.
777  if (CalleeCtx->getTranslationUnit() !=
778      Pred->getLocationContext()->getTranslationUnit()) {
779    // Create a new engine. We must be careful that the new engine should not
780    // reference data structures owned by the old engine.
781
782    AnalysisManager &OldMgr = Eng.SubEng.getAnalysisManager();
783
784    // Get the callee's translation unit.
785    idx::TranslationUnit *TU = CalleeCtx->getTranslationUnit();
786
787    // Create a new AnalysisManager with components of the callee's
788    // TranslationUnit.
789    // The Diagnostic is  actually shared when we create ASTUnits from AST files.
790    AnalysisManager AMgr(TU->getASTContext(), TU->getDiagnostic(),
791                         OldMgr.getLangOptions(),
792                         OldMgr.getPathDiagnosticClient(),
793                         OldMgr.getStoreManagerCreator(),
794                         OldMgr.getConstraintManagerCreator(),
795                         OldMgr.getCheckerManager(),
796                         OldMgr.getIndexer(),
797                         OldMgr.getMaxNodes(), OldMgr.getMaxVisit(),
798                         OldMgr.shouldVisualizeGraphviz(),
799                         OldMgr.shouldVisualizeUbigraph(),
800                         OldMgr.shouldPurgeDead(),
801                         OldMgr.shouldEagerlyAssume(),
802                         OldMgr.shouldTrimGraph(),
803                         OldMgr.shouldInlineCall(),
804                     OldMgr.getAnalysisContextManager().getUseUnoptimizedCFG(),
805                     OldMgr.getAnalysisContextManager().
806                         getCFGBuildOptions().AddImplicitDtors,
807                     OldMgr.getAnalysisContextManager().
808                         getCFGBuildOptions().AddInitializers,
809                     OldMgr.shouldEagerlyTrimExplodedGraph());
810    llvm::OwningPtr<TransferFuncs> TF(MakeCFRefCountTF(AMgr.getASTContext(),
811                                                         /* GCEnabled */ false,
812                                                        AMgr.getLangOptions()));
813    // Create the new engine.
814    ExprEngine NewEng(AMgr, TF.take());
815
816    // Create the new LocationContext.
817    AnalysisContext *NewAnaCtx = AMgr.getAnalysisContext(CalleeCtx->getDecl(),
818                                               CalleeCtx->getTranslationUnit());
819    const StackFrameContext *OldLocCtx = CalleeCtx;
820    const StackFrameContext *NewLocCtx = AMgr.getStackFrame(NewAnaCtx,
821                                               OldLocCtx->getParent(),
822                                               OldLocCtx->getCallSite(),
823                                               OldLocCtx->getCallSiteBlock(),
824                                               OldLocCtx->getIndex());
825
826    // Now create an initial state for the new engine.
827    const GRState *NewState = NewEng.getStateManager().MarshalState(state,
828                                                                    NewLocCtx);
829    ExplodedNodeSet ReturnNodes;
830    NewEng.ExecuteWorkListWithInitialState(NewLocCtx, AMgr.getMaxNodes(),
831                                           NewState, ReturnNodes);
832    return;
833  }
834
835  // Get the callee entry block.
836  const CFGBlock *Entry = &(CalleeCtx->getCFG()->getEntry());
837  assert(Entry->empty());
838  assert(Entry->succ_size() == 1);
839
840  // Get the solitary successor.
841  const CFGBlock *SuccB = *(Entry->succ_begin());
842
843  // Construct an edge representing the starting location in the callee.
844  BlockEdge Loc(Entry, SuccB, CalleeCtx);
845
846  bool isNew;
847  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
848  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
849
850  if (isNew)
851    Eng.WList->enqueue(Node);
852}
853
854void CallExitNodeBuilder::generateNode(const GRState *state) {
855  // Get the callee's location context.
856  const StackFrameContext *LocCtx
857                         = cast<StackFrameContext>(Pred->getLocationContext());
858  // When exiting an implicit automatic obj dtor call, the callsite is the Stmt
859  // that triggers the dtor.
860  PostStmt Loc(LocCtx->getCallSite(), LocCtx->getParent());
861  bool isNew;
862  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
863  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
864  if (isNew)
865    Eng.WList->enqueue(Node, LocCtx->getCallSiteBlock(),
866                       LocCtx->getIndex() + 1);
867}
868