CoreEngine.cpp revision b219cfc4d75f0a03630b7c4509ef791b7e97b2c8 
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//===----------------------------------------------------------------------===//
26// Worklist classes for exploration of reachable states.
27//===----------------------------------------------------------------------===//
28
29WorkList::Visitor::~Visitor() {}
30
31namespace {
32class DFS : public WorkList {
33  SmallVector<WorkListUnit,20> Stack;
34public:
35  virtual bool hasWork() const {
36    return !Stack.empty();
37  }
38
39  virtual void enqueue(const WorkListUnit& U) {
40    Stack.push_back(U);
41  }
42
43  virtual WorkListUnit dequeue() {
44    assert (!Stack.empty());
45    const WorkListUnit& U = Stack.back();
46    Stack.pop_back(); // This technically "invalidates" U, but we are fine.
47    return U;
48  }
49
50  virtual bool visitItemsInWorkList(Visitor &V) {
51    for (SmallVectorImpl<WorkListUnit>::iterator
52         I = Stack.begin(), E = Stack.end(); I != E; ++I) {
53      if (V.visit(*I))
54        return true;
55    }
56    return false;
57  }
58};
59
60class BFS : public WorkList {
61  std::deque<WorkListUnit> Queue;
62public:
63  virtual bool hasWork() const {
64    return !Queue.empty();
65  }
66
67  virtual void enqueue(const WorkListUnit& U) {
68    Queue.push_front(U);
69  }
70
71  virtual WorkListUnit dequeue() {
72    WorkListUnit U = Queue.front();
73    Queue.pop_front();
74    return U;
75  }
76
77  virtual bool visitItemsInWorkList(Visitor &V) {
78    for (std::deque<WorkListUnit>::iterator
79         I = Queue.begin(), E = Queue.end(); I != E; ++I) {
80      if (V.visit(*I))
81        return true;
82    }
83    return false;
84  }
85};
86
87} // end anonymous namespace
88
89// Place the dstor for WorkList here because it contains virtual member
90// functions, and we the code for the dstor generated in one compilation unit.
91WorkList::~WorkList() {}
92
93WorkList *WorkList::makeDFS() { return new DFS(); }
94WorkList *WorkList::makeBFS() { return new BFS(); }
95
96namespace {
97  class BFSBlockDFSContents : public WorkList {
98    std::deque<WorkListUnit> Queue;
99    SmallVector<WorkListUnit,20> Stack;
100  public:
101    virtual bool hasWork() const {
102      return !Queue.empty() || !Stack.empty();
103    }
104
105    virtual void enqueue(const WorkListUnit& U) {
106      if (isa<BlockEntrance>(U.getNode()->getLocation()))
107        Queue.push_front(U);
108      else
109        Stack.push_back(U);
110    }
111
112    virtual WorkListUnit dequeue() {
113      // Process all basic blocks to completion.
114      if (!Stack.empty()) {
115        const WorkListUnit& U = Stack.back();
116        Stack.pop_back(); // This technically "invalidates" U, but we are fine.
117        return U;
118      }
119
120      assert(!Queue.empty());
121      // Don't use const reference.  The subsequent pop_back() might make it
122      // unsafe.
123      WorkListUnit U = Queue.front();
124      Queue.pop_front();
125      return U;
126    }
127    virtual bool visitItemsInWorkList(Visitor &V) {
128      for (SmallVectorImpl<WorkListUnit>::iterator
129           I = Stack.begin(), E = Stack.end(); I != E; ++I) {
130        if (V.visit(*I))
131          return true;
132      }
133      for (std::deque<WorkListUnit>::iterator
134           I = Queue.begin(), E = Queue.end(); I != E; ++I) {
135        if (V.visit(*I))
136          return true;
137      }
138      return false;
139    }
140
141  };
142} // end anonymous namespace
143
144WorkList* WorkList::makeBFSBlockDFSContents() {
145  return new BFSBlockDFSContents();
146}
147
148//===----------------------------------------------------------------------===//
149// Core analysis engine.
150//===----------------------------------------------------------------------===//
151
152/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
153bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
154                                   const ProgramState *InitState) {
155
156  if (G->num_roots() == 0) { // Initialize the analysis by constructing
157    // the root if none exists.
158
159    const CFGBlock *Entry = &(L->getCFG()->getEntry());
160
161    assert (Entry->empty() &&
162            "Entry block must be empty.");
163
164    assert (Entry->succ_size() == 1 &&
165            "Entry block must have 1 successor.");
166
167    // Get the solitary successor.
168    const CFGBlock *Succ = *(Entry->succ_begin());
169
170    // Construct an edge representing the
171    // starting location in the function.
172    BlockEdge StartLoc(Entry, Succ, L);
173
174    // Set the current block counter to being empty.
175    WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
176
177    if (!InitState)
178      // Generate the root.
179      generateNode(StartLoc, SubEng.getInitialState(L), 0);
180    else
181      generateNode(StartLoc, InitState, 0);
182  }
183
184  // Check if we have a steps limit
185  bool UnlimitedSteps = Steps == 0;
186
187  while (WList->hasWork()) {
188    if (!UnlimitedSteps) {
189      if (Steps == 0)
190        break;
191      --Steps;
192    }
193
194    const WorkListUnit& WU = WList->dequeue();
195
196    // Set the current block counter.
197    WList->setBlockCounter(WU.getBlockCounter());
198
199    // Retrieve the node.
200    ExplodedNode *Node = WU.getNode();
201
202    // Dispatch on the location type.
203    switch (Node->getLocation().getKind()) {
204      case ProgramPoint::BlockEdgeKind:
205        HandleBlockEdge(cast<BlockEdge>(Node->getLocation()), Node);
206        break;
207
208      case ProgramPoint::BlockEntranceKind:
209        HandleBlockEntrance(cast<BlockEntrance>(Node->getLocation()), Node);
210        break;
211
212      case ProgramPoint::BlockExitKind:
213        assert (false && "BlockExit location never occur in forward analysis.");
214        break;
215
216      case ProgramPoint::CallEnterKind:
217        HandleCallEnter(cast<CallEnter>(Node->getLocation()), WU.getBlock(),
218                        WU.getIndex(), Node);
219        break;
220
221      case ProgramPoint::CallExitKind:
222        HandleCallExit(cast<CallExit>(Node->getLocation()), Node);
223        break;
224
225      default:
226        assert(isa<PostStmt>(Node->getLocation()) ||
227               isa<PostInitializer>(Node->getLocation()));
228        HandlePostStmt(WU.getBlock(), WU.getIndex(), Node);
229        break;
230    }
231  }
232
233  SubEng.processEndWorklist(hasWorkRemaining());
234  return WList->hasWork();
235}
236
237void CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
238                                                 unsigned Steps,
239                                                 const ProgramState *InitState,
240                                                 ExplodedNodeSet &Dst) {
241  ExecuteWorkList(L, Steps, InitState);
242  for (SmallVectorImpl<ExplodedNode*>::iterator I = G->EndNodes.begin(),
243                                           E = G->EndNodes.end(); I != E; ++I) {
244    Dst.Add(*I);
245  }
246}
247
248void CoreEngine::HandleCallEnter(const CallEnter &L, const CFGBlock *Block,
249                                   unsigned Index, ExplodedNode *Pred) {
250  CallEnterNodeBuilder Builder(*this, Pred, L.getCallExpr(),
251                                 L.getCalleeContext(), Block, Index);
252  SubEng.processCallEnter(Builder);
253}
254
255void CoreEngine::HandleCallExit(const CallExit &L, ExplodedNode *Pred) {
256  CallExitNodeBuilder Builder(*this, Pred);
257  SubEng.processCallExit(Builder);
258}
259
260void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
261
262  const CFGBlock *Blk = L.getDst();
263
264  // Check if we are entering the EXIT block.
265  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
266
267    assert (L.getLocationContext()->getCFG()->getExit().size() == 0
268            && "EXIT block cannot contain Stmts.");
269
270    // Process the final state transition.
271    EndOfFunctionNodeBuilder Builder(Blk, Pred, this);
272    SubEng.processEndOfFunction(Builder);
273
274    // This path is done. Don't enqueue any more nodes.
275    return;
276  }
277
278  // Call into the subengine to process entering the CFGBlock.
279  ExplodedNodeSet dstNodes;
280  BlockEntrance BE(Blk, Pred->getLocationContext());
281  GenericNodeBuilder<BlockEntrance> nodeBuilder(*this, Pred, BE);
282  SubEng.processCFGBlockEntrance(dstNodes, nodeBuilder);
283
284  if (dstNodes.empty()) {
285    if (!nodeBuilder.hasGeneratedNode) {
286      // Auto-generate a node and enqueue it to the worklist.
287      generateNode(BE, Pred->State, Pred);
288    }
289  }
290  else {
291    for (ExplodedNodeSet::iterator I = dstNodes.begin(), E = dstNodes.end();
292         I != E; ++I) {
293      WList->enqueue(*I);
294    }
295  }
296
297  for (SmallVectorImpl<ExplodedNode*>::const_iterator
298       I = nodeBuilder.sinks().begin(), E = nodeBuilder.sinks().end();
299       I != E; ++I) {
300    blocksExhausted.push_back(std::make_pair(L, *I));
301  }
302}
303
304void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
305                                       ExplodedNode *Pred) {
306
307  // Increment the block counter.
308  BlockCounter Counter = WList->getBlockCounter();
309  Counter = BCounterFactory.IncrementCount(Counter,
310                             Pred->getLocationContext()->getCurrentStackFrame(),
311                                           L.getBlock()->getBlockID());
312  WList->setBlockCounter(Counter);
313
314  // Process the entrance of the block.
315  if (CFGElement E = L.getFirstElement()) {
316    StmtNodeBuilder Builder(L.getBlock(), 0, Pred, this,
317                              SubEng.getStateManager());
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        break;
331
332      case Stmt::BinaryOperatorClass: // '&&' and '||'
333        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
334        return;
335
336      case Stmt::BinaryConditionalOperatorClass:
337      case Stmt::ConditionalOperatorClass:
338        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
339                     Term, B, Pred);
340        return;
341
342        // FIXME: Use constant-folding in CFG construction to simplify this
343        // case.
344
345      case Stmt::ChooseExprClass:
346        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
347        return;
348
349      case Stmt::DoStmtClass:
350        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
351        return;
352
353      case Stmt::ForStmtClass:
354        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
355        return;
356
357      case Stmt::ContinueStmtClass:
358      case Stmt::BreakStmtClass:
359      case Stmt::GotoStmtClass:
360        break;
361
362      case Stmt::IfStmtClass:
363        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
364        return;
365
366      case Stmt::IndirectGotoStmtClass: {
367        // Only 1 successor: the indirect goto dispatch block.
368        assert (B->succ_size() == 1);
369
370        IndirectGotoNodeBuilder
371           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
372                   *(B->succ_begin()), this);
373
374        SubEng.processIndirectGoto(builder);
375        return;
376      }
377
378      case Stmt::ObjCForCollectionStmtClass: {
379        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
380        //
381        //  (1) inside a basic block, which represents the binding of the
382        //      'element' variable to a value.
383        //  (2) in a terminator, which represents the branch.
384        //
385        // For (1), subengines will bind a value (i.e., 0 or 1) indicating
386        // whether or not collection contains any more elements.  We cannot
387        // just test to see if the element is nil because a container can
388        // contain nil elements.
389        HandleBranch(Term, Term, B, Pred);
390        return;
391      }
392
393      case Stmt::SwitchStmtClass: {
394        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
395                                    this);
396
397        SubEng.processSwitch(builder);
398        return;
399      }
400
401      case Stmt::WhileStmtClass:
402        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
403        return;
404    }
405  }
406
407  assert (B->succ_size() == 1 &&
408          "Blocks with no terminator should have at most 1 successor.");
409
410  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
411               Pred->State, Pred);
412}
413
414void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
415                                const CFGBlock * B, ExplodedNode *Pred) {
416  assert(B->succ_size() == 2);
417  BranchNodeBuilder Builder(B, *(B->succ_begin()), *(B->succ_begin()+1),
418                            Pred, this);
419  SubEng.processBranch(Cond, Term, Builder);
420}
421
422void CoreEngine::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
423                                  ExplodedNode *Pred) {
424  assert (!B->empty());
425
426  if (StmtIdx == B->size())
427    HandleBlockExit(B, Pred);
428  else {
429    StmtNodeBuilder Builder(B, StmtIdx, Pred, this,
430                              SubEng.getStateManager());
431    SubEng.processCFGElement((*B)[StmtIdx], Builder);
432  }
433}
434
435/// generateNode - Utility method to generate nodes, hook up successors,
436///  and add nodes to the worklist.
437void CoreEngine::generateNode(const ProgramPoint &Loc,
438                              const ProgramState *State,
439                              ExplodedNode *Pred) {
440
441  bool IsNew;
442  ExplodedNode *Node = G->getNode(Loc, State, &IsNew);
443
444  if (Pred)
445    Node->addPredecessor(Pred, *G);  // Link 'Node' with its predecessor.
446  else {
447    assert (IsNew);
448    G->addRoot(Node);  // 'Node' has no predecessor.  Make it a root.
449  }
450
451  // Only add 'Node' to the worklist if it was freshly generated.
452  if (IsNew) WList->enqueue(Node);
453}
454
455ExplodedNode *
456GenericNodeBuilderImpl::generateNodeImpl(const ProgramState *state,
457                                         ExplodedNode *pred,
458                                         ProgramPoint programPoint,
459                                         bool asSink) {
460
461  hasGeneratedNode = true;
462  bool isNew;
463  ExplodedNode *node = engine.getGraph().getNode(programPoint, state, &isNew);
464  if (pred)
465    node->addPredecessor(pred, engine.getGraph());
466  if (isNew) {
467    if (asSink) {
468      node->markAsSink();
469      sinksGenerated.push_back(node);
470    }
471    return node;
472  }
473  return 0;
474}
475
476StmtNodeBuilder::StmtNodeBuilder(const CFGBlock *b,
477                                 unsigned idx,
478                                 ExplodedNode *N,
479                                 CoreEngine* e,
480                                 ProgramStateManager &mgr)
481  : Eng(*e), B(*b), Idx(idx), Pred(N), Mgr(mgr),
482    PurgingDeadSymbols(false), BuildSinks(false), hasGeneratedNode(false),
483    PointKind(ProgramPoint::PostStmtKind), Tag(0) {
484  Deferred.insert(N);
485}
486
487StmtNodeBuilder::~StmtNodeBuilder() {
488  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
489    if (!(*I)->isSink())
490      GenerateAutoTransition(*I);
491}
492
493void StmtNodeBuilder::GenerateAutoTransition(ExplodedNode *N) {
494  assert (!N->isSink());
495
496  // Check if this node entered a callee.
497  if (isa<CallEnter>(N->getLocation())) {
498    // Still use the index of the CallExpr. It's needed to create the callee
499    // StackFrameContext.
500    Eng.WList->enqueue(N, &B, Idx);
501    return;
502  }
503
504  // Do not create extra nodes. Move to the next CFG element.
505  if (isa<PostInitializer>(N->getLocation())) {
506    Eng.WList->enqueue(N, &B, Idx+1);
507    return;
508  }
509
510  PostStmt Loc(getStmt(), N->getLocationContext());
511
512  if (Loc == N->getLocation()) {
513    // Note: 'N' should be a fresh node because otherwise it shouldn't be
514    // a member of Deferred.
515    Eng.WList->enqueue(N, &B, Idx+1);
516    return;
517  }
518
519  bool IsNew;
520  ExplodedNode *Succ = Eng.G->getNode(Loc, N->State, &IsNew);
521  Succ->addPredecessor(N, *Eng.G);
522
523  if (IsNew)
524    Eng.WList->enqueue(Succ, &B, Idx+1);
525}
526
527ExplodedNode *StmtNodeBuilder::MakeNode(ExplodedNodeSet &Dst,
528                                        const Stmt *S,
529                                        ExplodedNode *Pred,
530                                        const ProgramState *St,
531                                        ProgramPoint::Kind K) {
532
533  ExplodedNode *N = generateNode(S, St, Pred, K);
534
535  if (N) {
536    if (BuildSinks)
537      N->markAsSink();
538    else
539      Dst.Add(N);
540  }
541
542  return N;
543}
544
545static ProgramPoint GetProgramPoint(const Stmt *S, ProgramPoint::Kind K,
546                                    const LocationContext *LC,
547                                    const ProgramPointTag *tag){
548  switch (K) {
549    default:
550      llvm_unreachable("Unhandled ProgramPoint kind");
551    case ProgramPoint::PreStmtKind:
552      return PreStmt(S, LC, tag);
553    case ProgramPoint::PostStmtKind:
554      return PostStmt(S, LC, tag);
555    case ProgramPoint::PreLoadKind:
556      return PreLoad(S, LC, tag);
557    case ProgramPoint::PostLoadKind:
558      return PostLoad(S, LC, tag);
559    case ProgramPoint::PreStoreKind:
560      return PreStore(S, LC, tag);
561    case ProgramPoint::PostStoreKind:
562      return PostStore(S, LC, tag);
563    case ProgramPoint::PostLValueKind:
564      return PostLValue(S, LC, tag);
565    case ProgramPoint::PostPurgeDeadSymbolsKind:
566      return PostPurgeDeadSymbols(S, LC, tag);
567  }
568}
569
570ExplodedNode*
571StmtNodeBuilder::generateNodeInternal(const Stmt *S,
572                                      const ProgramState *state,
573                                      ExplodedNode *Pred,
574                                      ProgramPoint::Kind K,
575                                      const ProgramPointTag *tag) {
576
577  const ProgramPoint &L = GetProgramPoint(S, K, Pred->getLocationContext(),
578                                          tag);
579  return generateNodeInternal(L, state, Pred);
580}
581
582ExplodedNode*
583StmtNodeBuilder::generateNodeInternal(const ProgramPoint &Loc,
584                                      const ProgramState *State,
585                                      ExplodedNode *Pred) {
586  bool IsNew;
587  ExplodedNode *N = Eng.G->getNode(Loc, State, &IsNew);
588  N->addPredecessor(Pred, *Eng.G);
589  Deferred.erase(Pred);
590
591  if (IsNew) {
592    Deferred.insert(N);
593    return N;
594  }
595
596  return NULL;
597}
598
599// This function generate a new ExplodedNode but not a new branch(block edge).
600ExplodedNode *BranchNodeBuilder::generateNode(const Stmt *Condition,
601                                              const ProgramState *State) {
602  bool IsNew;
603
604  ExplodedNode *Succ
605    = Eng.G->getNode(PostCondition(Condition, Pred->getLocationContext()), State,
606                     &IsNew);
607
608  Succ->addPredecessor(Pred, *Eng.G);
609
610  Pred = Succ;
611
612  if (IsNew)
613    return Succ;
614
615  return NULL;
616}
617
618ExplodedNode *BranchNodeBuilder::generateNode(const ProgramState *State,
619                                              bool branch) {
620
621  // If the branch has been marked infeasible we should not generate a node.
622  if (!isFeasible(branch))
623    return NULL;
624
625  bool IsNew;
626
627  ExplodedNode *Succ =
628    Eng.G->getNode(BlockEdge(Src,branch ? DstT:DstF,Pred->getLocationContext()),
629                   State, &IsNew);
630
631  Succ->addPredecessor(Pred, *Eng.G);
632
633  if (branch)
634    GeneratedTrue = true;
635  else
636    GeneratedFalse = true;
637
638  if (IsNew) {
639    Deferred.push_back(Succ);
640    return Succ;
641  }
642
643  return NULL;
644}
645
646BranchNodeBuilder::~BranchNodeBuilder() {
647  if (!GeneratedTrue) generateNode(Pred->State, true);
648  if (!GeneratedFalse) generateNode(Pred->State, false);
649
650  for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
651    if (!(*I)->isSink()) Eng.WList->enqueue(*I);
652}
653
654
655ExplodedNode*
656IndirectGotoNodeBuilder::generateNode(const iterator &I,
657                                      const ProgramState *St,
658                                      bool isSink) {
659  bool IsNew;
660
661  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
662                                      Pred->getLocationContext()), St, &IsNew);
663
664  Succ->addPredecessor(Pred, *Eng.G);
665
666  if (IsNew) {
667
668    if (isSink)
669      Succ->markAsSink();
670    else
671      Eng.WList->enqueue(Succ);
672
673    return Succ;
674  }
675
676  return NULL;
677}
678
679
680ExplodedNode*
681SwitchNodeBuilder::generateCaseStmtNode(const iterator &I,
682                                        const ProgramState *St) {
683
684  bool IsNew;
685  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
686                                      Pred->getLocationContext()),
687                                      St, &IsNew);
688  Succ->addPredecessor(Pred, *Eng.G);
689  if (IsNew) {
690    Eng.WList->enqueue(Succ);
691    return Succ;
692  }
693  return NULL;
694}
695
696
697ExplodedNode*
698SwitchNodeBuilder::generateDefaultCaseNode(const ProgramState *St,
699                                           bool isSink) {
700  // Get the block for the default case.
701  assert (Src->succ_rbegin() != Src->succ_rend());
702  CFGBlock *DefaultBlock = *Src->succ_rbegin();
703
704  bool IsNew;
705
706  ExplodedNode *Succ = Eng.G->getNode(BlockEdge(Src, DefaultBlock,
707                                       Pred->getLocationContext()), St, &IsNew);
708  Succ->addPredecessor(Pred, *Eng.G);
709
710  if (IsNew) {
711    if (isSink)
712      Succ->markAsSink();
713    else
714      Eng.WList->enqueue(Succ);
715
716    return Succ;
717  }
718
719  return NULL;
720}
721
722EndOfFunctionNodeBuilder::~EndOfFunctionNodeBuilder() {
723  // Auto-generate an EOP node if one has not been generated.
724  if (!hasGeneratedNode) {
725    // If we are in an inlined call, generate CallExit node.
726    if (Pred->getLocationContext()->getParent())
727      GenerateCallExitNode(Pred->State);
728    else
729      generateNode(Pred->State);
730  }
731}
732
733ExplodedNode*
734EndOfFunctionNodeBuilder::generateNode(const ProgramState *State,
735                                       ExplodedNode *P,
736                                       const ProgramPointTag *tag) {
737  hasGeneratedNode = true;
738  bool IsNew;
739
740  ExplodedNode *Node = Eng.G->getNode(BlockEntrance(&B,
741                               Pred->getLocationContext(), tag ? tag : Tag),
742                               State, &IsNew);
743
744  Node->addPredecessor(P ? P : Pred, *Eng.G);
745
746  if (IsNew) {
747    Eng.G->addEndOfPath(Node);
748    return Node;
749  }
750
751  return NULL;
752}
753
754void EndOfFunctionNodeBuilder::GenerateCallExitNode(const ProgramState *state) {
755  hasGeneratedNode = true;
756  // Create a CallExit node and enqueue it.
757  const StackFrameContext *LocCtx
758                         = cast<StackFrameContext>(Pred->getLocationContext());
759  const Stmt *CE = LocCtx->getCallSite();
760
761  // Use the the callee location context.
762  CallExit Loc(CE, LocCtx);
763
764  bool isNew;
765  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
766  Node->addPredecessor(Pred, *Eng.G);
767
768  if (isNew)
769    Eng.WList->enqueue(Node);
770}
771
772
773void CallEnterNodeBuilder::generateNode(const ProgramState *state) {
774  // Check if the callee is in the same translation unit.
775  if (CalleeCtx->getTranslationUnit() !=
776      Pred->getLocationContext()->getTranslationUnit()) {
777    // Create a new engine. We must be careful that the new engine should not
778    // reference data structures owned by the old engine.
779
780    AnalysisManager &OldMgr = Eng.SubEng.getAnalysisManager();
781
782    // Get the callee's translation unit.
783    idx::TranslationUnit *TU = CalleeCtx->getTranslationUnit();
784
785    // Create a new AnalysisManager with components of the callee's
786    // TranslationUnit.
787    // The Diagnostic is  actually shared when we create ASTUnits from AST files.
788    AnalysisManager AMgr(TU->getASTContext(), TU->getDiagnostic(),
789                         OldMgr.getLangOptions(),
790                         OldMgr.getPathDiagnosticClient(),
791                         OldMgr.getStoreManagerCreator(),
792                         OldMgr.getConstraintManagerCreator(),
793                         OldMgr.getCheckerManager(),
794                         OldMgr.getIndexer(),
795                         OldMgr.getMaxNodes(), OldMgr.getMaxVisit(),
796                         OldMgr.shouldVisualizeGraphviz(),
797                         OldMgr.shouldVisualizeUbigraph(),
798                         OldMgr.shouldPurgeDead(),
799                         OldMgr.shouldEagerlyAssume(),
800                         OldMgr.shouldTrimGraph(),
801                         OldMgr.shouldInlineCall(),
802                     OldMgr.getAnalysisContextManager().getUseUnoptimizedCFG(),
803                     OldMgr.getAnalysisContextManager().
804                         getCFGBuildOptions().AddImplicitDtors,
805                     OldMgr.getAnalysisContextManager().
806                         getCFGBuildOptions().AddInitializers,
807                     OldMgr.shouldEagerlyTrimExplodedGraph());
808    // Create the new engine.
809    // FIXME: This cast isn't really safe.
810    bool GCEnabled = static_cast<ExprEngine&>(Eng.SubEng).isObjCGCEnabled();
811    ExprEngine NewEng(AMgr, GCEnabled);
812
813    // Create the new LocationContext.
814    AnalysisContext *NewAnaCtx = AMgr.getAnalysisContext(CalleeCtx->getDecl(),
815                                               CalleeCtx->getTranslationUnit());
816    const StackFrameContext *OldLocCtx = CalleeCtx;
817    const StackFrameContext *NewLocCtx = AMgr.getStackFrame(NewAnaCtx,
818                                               OldLocCtx->getParent(),
819                                               OldLocCtx->getCallSite(),
820                                               OldLocCtx->getCallSiteBlock(),
821                                               OldLocCtx->getIndex());
822
823    // Now create an initial state for the new engine.
824    const ProgramState *NewState =
825      NewEng.getStateManager().MarshalState(state, NewLocCtx);
826    ExplodedNodeSet ReturnNodes;
827    NewEng.ExecuteWorkListWithInitialState(NewLocCtx, AMgr.getMaxNodes(),
828                                           NewState, ReturnNodes);
829    return;
830  }
831
832  // Get the callee entry block.
833  const CFGBlock *Entry = &(CalleeCtx->getCFG()->getEntry());
834  assert(Entry->empty());
835  assert(Entry->succ_size() == 1);
836
837  // Get the solitary successor.
838  const CFGBlock *SuccB = *(Entry->succ_begin());
839
840  // Construct an edge representing the starting location in the callee.
841  BlockEdge Loc(Entry, SuccB, CalleeCtx);
842
843  bool isNew;
844  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
845  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
846
847  if (isNew)
848    Eng.WList->enqueue(Node);
849}
850
851void CallExitNodeBuilder::generateNode(const ProgramState *state) {
852  // Get the callee's location context.
853  const StackFrameContext *LocCtx
854                         = cast<StackFrameContext>(Pred->getLocationContext());
855  // When exiting an implicit automatic obj dtor call, the callsite is the Stmt
856  // that triggers the dtor.
857  PostStmt Loc(LocCtx->getCallSite(), LocCtx->getParent());
858  bool isNew;
859  ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
860  Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
861  if (isNew)
862    Eng.WList->enqueue(Node, LocCtx->getCallSiteBlock(),
863                       LocCtx->getIndex() + 1);
864}
865