CoreEngine.cpp revision 226633 
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 "clang/AST/StmtCXX.h"
21#include "llvm/Support/Casting.h"
22#include "llvm/ADT/DenseMap.h"
23using namespace clang;
24using namespace ento;
25
26//===----------------------------------------------------------------------===//
27// Worklist classes for exploration of reachable states.
28//===----------------------------------------------------------------------===//
29
30WorkList::Visitor::~Visitor() {}
31
32namespace {
33class DFS : public WorkList {
34  SmallVector<WorkListUnit,20> Stack;
35public:
36  virtual bool hasWork() const {
37    return !Stack.empty();
38  }
39
40  virtual void enqueue(const WorkListUnit& U) {
41    Stack.push_back(U);
42  }
43
44  virtual WorkListUnit dequeue() {
45    assert (!Stack.empty());
46    const WorkListUnit& U = Stack.back();
47    Stack.pop_back(); // This technically "invalidates" U, but we are fine.
48    return U;
49  }
50
51  virtual bool visitItemsInWorkList(Visitor &V) {
52    for (SmallVectorImpl<WorkListUnit>::iterator
53         I = Stack.begin(), E = Stack.end(); I != E; ++I) {
54      if (V.visit(*I))
55        return true;
56    }
57    return false;
58  }
59};
60
61class BFS : public WorkList {
62  std::deque<WorkListUnit> Queue;
63public:
64  virtual bool hasWork() const {
65    return !Queue.empty();
66  }
67
68  virtual void enqueue(const WorkListUnit& U) {
69    Queue.push_front(U);
70  }
71
72  virtual WorkListUnit dequeue() {
73    WorkListUnit U = Queue.front();
74    Queue.pop_front();
75    return U;
76  }
77
78  virtual bool visitItemsInWorkList(Visitor &V) {
79    for (std::deque<WorkListUnit>::iterator
80         I = Queue.begin(), E = Queue.end(); I != E; ++I) {
81      if (V.visit(*I))
82        return true;
83    }
84    return false;
85  }
86};
87
88} // end anonymous namespace
89
90// Place the dstor for WorkList here because it contains virtual member
91// functions, and we the code for the dstor generated in one compilation unit.
92WorkList::~WorkList() {}
93
94WorkList *WorkList::makeDFS() { return new DFS(); }
95WorkList *WorkList::makeBFS() { return new BFS(); }
96
97namespace {
98  class BFSBlockDFSContents : public WorkList {
99    std::deque<WorkListUnit> Queue;
100    SmallVector<WorkListUnit,20> Stack;
101  public:
102    virtual bool hasWork() const {
103      return !Queue.empty() || !Stack.empty();
104    }
105
106    virtual void enqueue(const WorkListUnit& U) {
107      if (isa<BlockEntrance>(U.getNode()->getLocation()))
108        Queue.push_front(U);
109      else
110        Stack.push_back(U);
111    }
112
113    virtual WorkListUnit dequeue() {
114      // Process all basic blocks to completion.
115      if (!Stack.empty()) {
116        const WorkListUnit& U = Stack.back();
117        Stack.pop_back(); // This technically "invalidates" U, but we are fine.
118        return U;
119      }
120
121      assert(!Queue.empty());
122      // Don't use const reference.  The subsequent pop_back() might make it
123      // unsafe.
124      WorkListUnit U = Queue.front();
125      Queue.pop_front();
126      return U;
127    }
128    virtual bool visitItemsInWorkList(Visitor &V) {
129      for (SmallVectorImpl<WorkListUnit>::iterator
130           I = Stack.begin(), E = Stack.end(); I != E; ++I) {
131        if (V.visit(*I))
132          return true;
133      }
134      for (std::deque<WorkListUnit>::iterator
135           I = Queue.begin(), E = Queue.end(); I != E; ++I) {
136        if (V.visit(*I))
137          return true;
138      }
139      return false;
140    }
141
142  };
143} // end anonymous namespace
144
145WorkList* WorkList::makeBFSBlockDFSContents() {
146  return new BFSBlockDFSContents();
147}
148
149//===----------------------------------------------------------------------===//
150// Core analysis engine.
151//===----------------------------------------------------------------------===//
152
153/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
154bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
155                                   const ProgramState *InitState) {
156
157  if (G->num_roots() == 0) { // Initialize the analysis by constructing
158    // the root if none exists.
159
160    const CFGBlock *Entry = &(L->getCFG()->getEntry());
161
162    assert (Entry->empty() &&
163            "Entry block must be empty.");
164
165    assert (Entry->succ_size() == 1 &&
166            "Entry block must have 1 successor.");
167
168    // Get the solitary successor.
169    const CFGBlock *Succ = *(Entry->succ_begin());
170
171    // Construct an edge representing the
172    // starting location in the function.
173    BlockEdge StartLoc(Entry, Succ, L);
174
175    // Set the current block counter to being empty.
176    WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
177
178    if (!InitState)
179      // Generate the root.
180      generateNode(StartLoc, SubEng.getInitialState(L), 0);
181    else
182      generateNode(StartLoc, InitState, 0);
183  }
184
185  // Check if we have a steps limit
186  bool UnlimitedSteps = Steps == 0;
187
188  while (WList->hasWork()) {
189    if (!UnlimitedSteps) {
190      if (Steps == 0)
191        break;
192      --Steps;
193    }
194
195    const WorkListUnit& WU = WList->dequeue();
196
197    // Set the current block counter.
198    WList->setBlockCounter(WU.getBlockCounter());
199
200    // Retrieve the node.
201    ExplodedNode *Node = WU.getNode();
202
203    // Dispatch on the location type.
204    switch (Node->getLocation().getKind()) {
205      case ProgramPoint::BlockEdgeKind:
206        HandleBlockEdge(cast<BlockEdge>(Node->getLocation()), Node);
207        break;
208
209      case ProgramPoint::BlockEntranceKind:
210        HandleBlockEntrance(cast<BlockEntrance>(Node->getLocation()), Node);
211        break;
212
213      case ProgramPoint::BlockExitKind:
214        assert (false && "BlockExit location never occur in forward analysis.");
215        break;
216
217      case ProgramPoint::CallEnterKind:
218        HandleCallEnter(cast<CallEnter>(Node->getLocation()), WU.getBlock(),
219                        WU.getIndex(), Node);
220        break;
221
222      case ProgramPoint::CallExitKind:
223        HandleCallExit(cast<CallExit>(Node->getLocation()), Node);
224        break;
225
226      default:
227        assert(isa<PostStmt>(Node->getLocation()) ||
228               isa<PostInitializer>(Node->getLocation()));
229        HandlePostStmt(WU.getBlock(), WU.getIndex(), Node);
230        break;
231    }
232  }
233
234  SubEng.processEndWorklist(hasWorkRemaining());
235  return WList->hasWork();
236}
237
238void CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
239                                                 unsigned Steps,
240                                                 const ProgramState *InitState,
241                                                 ExplodedNodeSet &Dst) {
242  ExecuteWorkList(L, Steps, InitState);
243  for (SmallVectorImpl<ExplodedNode*>::iterator I = G->EndNodes.begin(),
244                                           E = G->EndNodes.end(); I != E; ++I) {
245    Dst.Add(*I);
246  }
247}
248
249void CoreEngine::HandleCallEnter(const CallEnter &L, const CFGBlock *Block,
250                                   unsigned Index, ExplodedNode *Pred) {
251  CallEnterNodeBuilder Builder(*this, Pred, L.getCallExpr(),
252                                 L.getCalleeContext(), Block, Index);
253  SubEng.processCallEnter(Builder);
254}
255
256void CoreEngine::HandleCallExit(const CallExit &L, ExplodedNode *Pred) {
257  CallExitNodeBuilder Builder(*this, Pred);
258  SubEng.processCallExit(Builder);
259}
260
261void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
262
263  const CFGBlock *Blk = L.getDst();
264
265  // Check if we are entering the EXIT block.
266  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
267
268    assert (L.getLocationContext()->getCFG()->getExit().size() == 0
269            && "EXIT block cannot contain Stmts.");
270
271    // Process the final state transition.
272    EndOfFunctionNodeBuilder Builder(Blk, Pred, this);
273    SubEng.processEndOfFunction(Builder);
274
275    // This path is done. Don't enqueue any more nodes.
276    return;
277  }
278
279  // Call into the subengine to process entering the CFGBlock.
280  ExplodedNodeSet dstNodes;
281  BlockEntrance BE(Blk, Pred->getLocationContext());
282  GenericNodeBuilder<BlockEntrance> nodeBuilder(*this, Pred, BE);
283  SubEng.processCFGBlockEntrance(dstNodes, nodeBuilder);
284
285  if (dstNodes.empty()) {
286    if (!nodeBuilder.hasGeneratedNode) {
287      // Auto-generate a node and enqueue it to the worklist.
288      generateNode(BE, Pred->State, Pred);
289    }
290  }
291  else {
292    for (ExplodedNodeSet::iterator I = dstNodes.begin(), E = dstNodes.end();
293         I != E; ++I) {
294      WList->enqueue(*I);
295    }
296  }
297
298  for (SmallVectorImpl<ExplodedNode*>::const_iterator
299       I = nodeBuilder.sinks().begin(), E = nodeBuilder.sinks().end();
300       I != E; ++I) {
301    blocksExhausted.push_back(std::make_pair(L, *I));
302  }
303}
304
305void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
306                                       ExplodedNode *Pred) {
307
308  // Increment the block counter.
309  BlockCounter Counter = WList->getBlockCounter();
310  Counter = BCounterFactory.IncrementCount(Counter,
311                             Pred->getLocationContext()->getCurrentStackFrame(),
312                                           L.getBlock()->getBlockID());
313  WList->setBlockCounter(Counter);
314
315  // Process the entrance of the block.
316  if (CFGElement E = L.getFirstElement()) {
317    StmtNodeBuilder Builder(L.getBlock(), 0, Pred, this);
318    SubEng.processCFGElement(E, Builder);
319  }
320  else
321    HandleBlockExit(L.getBlock(), Pred);
322}
323
324void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
325
326  if (const Stmt *Term = B->getTerminator()) {
327    switch (Term->getStmtClass()) {
328      default:
329        llvm_unreachable("Analysis for this terminator not implemented.");
330
331      case Stmt::BinaryOperatorClass: // '&&' and '||'
332        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
333        return;
334
335      case Stmt::BinaryConditionalOperatorClass:
336      case Stmt::ConditionalOperatorClass:
337        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
338                     Term, B, Pred);
339        return;
340
341        // FIXME: Use constant-folding in CFG construction to simplify this
342        // case.
343
344      case Stmt::ChooseExprClass:
345        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
346        return;
347
348      case Stmt::DoStmtClass:
349        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
350        return;
351
352      case Stmt::CXXForRangeStmtClass:
353        HandleBranch(cast<CXXForRangeStmt>(Term)->getCond(), Term, B, Pred);
354        return;
355
356      case Stmt::ForStmtClass:
357        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
358        return;
359
360      case Stmt::ContinueStmtClass:
361      case Stmt::BreakStmtClass:
362      case Stmt::GotoStmtClass:
363        break;
364
365      case Stmt::IfStmtClass:
366        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
367        return;
368
369      case Stmt::IndirectGotoStmtClass: {
370        // Only 1 successor: the indirect goto dispatch block.
371        assert (B->succ_size() == 1);
372
373        IndirectGotoNodeBuilder
374           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
375                   *(B->succ_begin()), this);
376
377        SubEng.processIndirectGoto(builder);
378        return;
379      }
380
381      case Stmt::ObjCForCollectionStmtClass: {
382        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
383        //
384        //  (1) inside a basic block, which represents the binding of the
385        //      'element' variable to a value.
386        //  (2) in a terminator, which represents the branch.
387        //
388        // For (1), subengines will bind a value (i.e., 0 or 1) indicating
389        // whether or not collection contains any more elements.  We cannot
390        // just test to see if the element is nil because a container can
391        // contain nil elements.
392        HandleBranch(Term, Term, B, Pred);
393        return;
394      }
395
396      case Stmt::SwitchStmtClass: {
397        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
398                                    this);
399
400        SubEng.processSwitch(builder);
401        return;
402      }
403
404      case Stmt::WhileStmtClass:
405        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
406        return;
407    }
408  }
409
410  assert (B->succ_size() == 1 &&
411          "Blocks with no terminator should have at most 1 successor.");
412
413  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
414               Pred->State, Pred);
415}
416
417void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
418                                const CFGBlock * B, ExplodedNode *Pred) {
419  assert(B->succ_size() == 2);
420  BranchNodeBuilder Builder(B, *(B->succ_begin()), *(B->succ_begin()+1),
421                            Pred, this);
422  SubEng.processBranch(Cond, Term, Builder);
423}
424
425void CoreEngine::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
426                                  ExplodedNode *Pred) {
427  assert (!B->empty());
428
429  if (StmtIdx == B->size())
430    HandleBlockExit(B, Pred);
431  else {
432    StmtNodeBuilder Builder(B, StmtIdx, Pred, this);
433    SubEng.processCFGElement((*B)[StmtIdx], Builder);
434  }
435}
436
437/// generateNode - Utility method to generate nodes, hook up successors,
438///  and add nodes to the worklist.
439void CoreEngine::generateNode(const ProgramPoint &Loc,
440                              const ProgramState *State,
441                              ExplodedNode *Pred) {
442
443  bool IsNew;
444  ExplodedNode *Node = G->getNode(Loc, State, &IsNew);
445
446  if (Pred)
447    Node->addPredecessor(Pred, *G);  // Link 'Node' with its predecessor.
448  else {
449    assert (IsNew);
450    G->addRoot(Node);  // 'Node' has no predecessor.  Make it a root.
451  }
452
453  // Only add 'Node' to the worklist if it was freshly generated.
454  if (IsNew) WList->enqueue(Node);
455}
456
457ExplodedNode *
458GenericNodeBuilderImpl::generateNodeImpl(const ProgramState *state,
459                                         ExplodedNode *pred,
460                                         ProgramPoint programPoint,
461                                         bool asSink) {
462
463  hasGeneratedNode = true;
464  bool isNew;
465  ExplodedNode *node = engine.getGraph().getNode(programPoint, state, &isNew);
466  if (pred)
467    node->addPredecessor(pred, engine.getGraph());
468  if (isNew) {
469    if (asSink) {
470      node->markAsSink();
471      sinksGenerated.push_back(node);
472    }
473    return node;
474  }
475  return 0;
476}
477
478StmtNodeBuilder::StmtNodeBuilder(const CFGBlock *b,
479                                 unsigned idx,
480                                 ExplodedNode *N,
481                                 CoreEngine* e)
482  : Eng(*e), B(*b), Idx(idx), Pred(N),
483    PurgingDeadSymbols(false), BuildSinks(false), hasGeneratedNode(false),
484    PointKind(ProgramPoint::PostStmtKind), Tag(0) {
485  Deferred.insert(N);
486}
487
488StmtNodeBuilder::~StmtNodeBuilder() {
489  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
490    if (!(*I)->isSink())
491      GenerateAutoTransition(*I);
492}
493
494void StmtNodeBuilder::GenerateAutoTransition(ExplodedNode *N) {
495  assert (!N->isSink());
496
497  // Check if this node entered a callee.
498  if (isa<CallEnter>(N->getLocation())) {
499    // Still use the index of the CallExpr. It's needed to create the callee
500    // StackFrameContext.
501    Eng.WList->enqueue(N, &B, Idx);
502    return;
503  }
504
505  // Do not create extra nodes. Move to the next CFG element.
506  if (isa<PostInitializer>(N->getLocation())) {
507    Eng.WList->enqueue(N, &B, Idx+1);
508    return;
509  }
510
511  PostStmt Loc(getStmt(), N->getLocationContext());
512
513  if (Loc == N->getLocation()) {
514    // Note: 'N' should be a fresh node because otherwise it shouldn't be
515    // a member of Deferred.
516    Eng.WList->enqueue(N, &B, Idx+1);
517    return;
518  }
519
520  bool IsNew;
521  ExplodedNode *Succ = Eng.G->getNode(Loc, N->State, &IsNew);
522  Succ->addPredecessor(N, *Eng.G);
523
524  if (IsNew)
525    Eng.WList->enqueue(Succ, &B, Idx+1);
526}
527
528ExplodedNode *StmtNodeBuilder::MakeNode(ExplodedNodeSet &Dst,
529                                        const Stmt *S,
530                                        ExplodedNode *Pred,
531                                        const ProgramState *St,
532                                        ProgramPoint::Kind K) {
533
534  ExplodedNode *N = generateNode(S, St, Pred, K);
535
536  if (N) {
537    if (BuildSinks)
538      N->markAsSink();
539    else
540      Dst.Add(N);
541  }
542
543  return N;
544}
545
546ExplodedNode*
547StmtNodeBuilder::generateNodeInternal(const Stmt *S,
548                                      const ProgramState *state,
549                                      ExplodedNode *Pred,
550                                      ProgramPoint::Kind K,
551                                      const ProgramPointTag *tag) {
552
553  const ProgramPoint &L = ProgramPoint::getProgramPoint(S, K,
554                                        Pred->getLocationContext(), tag);
555  return generateNodeInternal(L, state, Pred);
556}
557
558ExplodedNode*
559StmtNodeBuilder::generateNodeInternal(const ProgramPoint &Loc,
560                                      const ProgramState *State,
561                                      ExplodedNode *Pred) {
562  bool IsNew;
563  ExplodedNode *N = Eng.G->getNode(Loc, State, &IsNew);
564  N->addPredecessor(Pred, *Eng.G);
565  Deferred.erase(Pred);
566
567  if (IsNew) {
568    Deferred.insert(N);
569    return N;
570  }
571
572  return NULL;
573}
574
575// This function generate a new ExplodedNode but not a new branch(block edge).
576ExplodedNode *BranchNodeBuilder::generateNode(const Stmt *Condition,
577                                              const ProgramState *State) {
578  bool IsNew;
579
580  ExplodedNode *Succ
581    = Eng.G->getNode(PostCondition(Condition, Pred->getLocationContext()), State,
582                     &IsNew);
583
584  Succ->addPredecessor(Pred, *Eng.G);
585
586  Pred = Succ;
587
588  if (IsNew)
589    return Succ;
590
591  return NULL;
592}
593
594ExplodedNode *BranchNodeBuilder::generateNode(const ProgramState *State,
595                                              bool branch) {
596
597  // If the branch has been marked infeasible we should not generate a node.
598  if (!isFeasible(branch))
599    return NULL;
600
601  bool IsNew;
602
603  ExplodedNode *Succ =
604    Eng.G->getNode(BlockEdge(Src,branch ? DstT:DstF,Pred->getLocationContext()),
605                   State, &IsNew);
606
607  Succ->addPredecessor(Pred, *Eng.G);
608
609  if (branch)
610    GeneratedTrue = true;
611  else
612    GeneratedFalse = true;
613
614  if (IsNew) {
615    Deferred.push_back(Succ);
616    return Succ;
617  }
618
619  return NULL;
620}
621
622BranchNodeBuilder::~BranchNodeBuilder() {
623  if (!GeneratedTrue) generateNode(Pred->State, true);
624  if (!GeneratedFalse) generateNode(Pred->State, false);
625
626  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
627    if (!(*I)->isSink()) Eng.WList->enqueue(*I);
628}
629
630
631ExplodedNode*
632IndirectGotoNodeBuilder::generateNode(const iterator &I,
633                                      const ProgramState *St,
634                                      bool isSink) {
635  bool IsNew;
636
637  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
638                                      Pred->getLocationContext()), St, &IsNew);
639
640  Succ->addPredecessor(Pred, *Eng.G);
641
642  if (IsNew) {
643
644    if (isSink)
645      Succ->markAsSink();
646    else
647      Eng.WList->enqueue(Succ);
648
649    return Succ;
650  }
651
652  return NULL;
653}
654
655
656ExplodedNode*
657SwitchNodeBuilder::generateCaseStmtNode(const iterator &I,
658                                        const ProgramState *St) {
659
660  bool IsNew;
661  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
662                                      Pred->getLocationContext()),
663                                      St, &IsNew);
664  Succ->addPredecessor(Pred, *Eng.G);
665  if (IsNew) {
666    Eng.WList->enqueue(Succ);
667    return Succ;
668  }
669  return NULL;
670}
671
672
673ExplodedNode*
674SwitchNodeBuilder::generateDefaultCaseNode(const ProgramState *St,
675                                           bool isSink) {
676  // Get the block for the default case.
677  assert(Src->succ_rbegin() != Src->succ_rend());
678  CFGBlock *DefaultBlock = *Src->succ_rbegin();
679
680  // Sanity check for default blocks that are unreachable and not caught
681  // by earlier stages.
682  if (!DefaultBlock)
683    return NULL;
684
685  bool IsNew;
686
687  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, DefaultBlock,
688                                      Pred->getLocationContext()), St, &IsNew);
689  Succ->addPredecessor(Pred, *Eng.G);
690
691  if (IsNew) {
692    if (isSink)
693      Succ->markAsSink();
694    else
695      Eng.WList->enqueue(Succ);
696
697    return Succ;
698  }
699
700  return NULL;
701}
702
703EndOfFunctionNodeBuilder::~EndOfFunctionNodeBuilder() {
704  // Auto-generate an EOP node if one has not been generated.
705  if (!hasGeneratedNode) {
706    // If we are in an inlined call, generate CallExit node.
707    if (Pred->getLocationContext()->getParent())
708      GenerateCallExitNode(Pred->State);
709    else
710      generateNode(Pred->State);
711  }
712}
713
714ExplodedNode*
715EndOfFunctionNodeBuilder::generateNode(const ProgramState *State,
716                                       ExplodedNode *P,
717                                       const ProgramPointTag *tag) {
718  hasGeneratedNode = true;
719  bool IsNew;
720
721  ExplodedNode *Node = Eng.G->getNode(BlockEntrance(&B,
722                               Pred->getLocationContext(), tag ? tag : Tag),
723                               State, &IsNew);
724
725  Node->addPredecessor(P ? P : Pred, *Eng.G);
726
727  if (IsNew) {
728    Eng.G->addEndOfPath(Node);
729    return Node;
730  }
731
732  return NULL;
733}
734
735void EndOfFunctionNodeBuilder::GenerateCallExitNode(const ProgramState *state) {
736  hasGeneratedNode = true;
737  // Create a CallExit node and enqueue it.
738  const StackFrameContext *LocCtx
739                         = cast<StackFrameContext>(Pred->getLocationContext());
740  const Stmt *CE = LocCtx->getCallSite();
741
742  // Use the the callee location context.
743  CallExit Loc(CE, LocCtx);
744
745  bool isNew;
746  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
747  Node->addPredecessor(Pred, *Eng.G);
748
749  if (isNew)
750    Eng.WList->enqueue(Node);
751}
752
753
754void CallEnterNodeBuilder::generateNode(const ProgramState *state) {
755  // Check if the callee is in the same translation unit.
756  if (CalleeCtx->getTranslationUnit() !=
757      Pred->getLocationContext()->getTranslationUnit()) {
758    // Create a new engine. We must be careful that the new engine should not
759    // reference data structures owned by the old engine.
760
761    AnalysisManager &OldMgr = Eng.SubEng.getAnalysisManager();
762
763    // Get the callee's translation unit.
764    idx::TranslationUnit *TU = CalleeCtx->getTranslationUnit();
765
766    // Create a new AnalysisManager with components of the callee's
767    // TranslationUnit.
768    // The Diagnostic is  actually shared when we create ASTUnits from AST files.
769    AnalysisManager AMgr(TU->getASTContext(), TU->getDiagnostic(), OldMgr);
770
771    // Create the new engine.
772    // FIXME: This cast isn't really safe.
773    bool GCEnabled = static_cast<ExprEngine&>(Eng.SubEng).isObjCGCEnabled();
774    ExprEngine NewEng(AMgr, GCEnabled);
775
776    // Create the new LocationContext.
777    AnalysisContext *NewAnaCtx = AMgr.getAnalysisContext(CalleeCtx->getDecl(),
778                                               CalleeCtx->getTranslationUnit());
779    const StackFrameContext *OldLocCtx = CalleeCtx;
780    const StackFrameContext *NewLocCtx = AMgr.getStackFrame(NewAnaCtx,
781                                               OldLocCtx->getParent(),
782                                               OldLocCtx->getCallSite(),
783                                               OldLocCtx->getCallSiteBlock(),
784                                               OldLocCtx->getIndex());
785
786    // Now create an initial state for the new engine.
787    const ProgramState *NewState =
788      NewEng.getStateManager().MarshalState(state, NewLocCtx);
789    ExplodedNodeSet ReturnNodes;
790    NewEng.ExecuteWorkListWithInitialState(NewLocCtx, AMgr.getMaxNodes(),
791                                           NewState, ReturnNodes);
792    return;
793  }
794
795  // Get the callee entry block.
796  const CFGBlock *Entry = &(CalleeCtx->getCFG()->getEntry());
797  assert(Entry->empty());
798  assert(Entry->succ_size() == 1);
799
800  // Get the solitary successor.
801  const CFGBlock *SuccB = *(Entry->succ_begin());
802
803  // Construct an edge representing the starting location in the callee.
804  BlockEdge Loc(Entry, SuccB, CalleeCtx);
805
806  bool isNew;
807  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
808  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
809
810  if (isNew)
811    Eng.WList->enqueue(Node);
812}
813
814void CallExitNodeBuilder::generateNode(const ProgramState *state) {
815  // Get the callee's location context.
816  const StackFrameContext *LocCtx
817                         = cast<StackFrameContext>(Pred->getLocationContext());
818  // When exiting an implicit automatic obj dtor call, the callsite is the Stmt
819  // that triggers the dtor.
820  PostStmt Loc(LocCtx->getCallSite(), LocCtx->getParent());
821  bool isNew;
822  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
823  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
824  if (isNew)
825    Eng.WList->enqueue(Node, LocCtx->getCallSiteBlock(),
826                       LocCtx->getIndex() + 1);
827}
828