CoreEngine.cpp revision 309124 
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/CoreEngine.h"
16#include "clang/AST/Expr.h"
17#include "clang/AST/ExprCXX.h"
18#include "clang/AST/StmtCXX.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
20#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/Support/Casting.h"
24
25using namespace clang;
26using namespace ento;
27
28#define DEBUG_TYPE "CoreEngine"
29
30STATISTIC(NumSteps,
31            "The # of steps executed.");
32STATISTIC(NumReachedMaxSteps,
33            "The # of times we reached the max number of steps.");
34STATISTIC(NumPathsExplored,
35            "The # of paths explored by the analyzer.");
36
37//===----------------------------------------------------------------------===//
38// Worklist classes for exploration of reachable states.
39//===----------------------------------------------------------------------===//
40
41WorkList::Visitor::~Visitor() {}
42
43namespace {
44class DFS : public WorkList {
45  SmallVector<WorkListUnit,20> Stack;
46public:
47  bool hasWork() const override {
48    return !Stack.empty();
49  }
50
51  void enqueue(const WorkListUnit& U) override {
52    Stack.push_back(U);
53  }
54
55  WorkListUnit dequeue() override {
56    assert (!Stack.empty());
57    const WorkListUnit& U = Stack.back();
58    Stack.pop_back(); // This technically "invalidates" U, but we are fine.
59    return U;
60  }
61
62  bool visitItemsInWorkList(Visitor &V) override {
63    for (SmallVectorImpl<WorkListUnit>::iterator
64         I = Stack.begin(), E = Stack.end(); I != E; ++I) {
65      if (V.visit(*I))
66        return true;
67    }
68    return false;
69  }
70};
71
72class BFS : public WorkList {
73  std::deque<WorkListUnit> Queue;
74public:
75  bool hasWork() const override {
76    return !Queue.empty();
77  }
78
79  void enqueue(const WorkListUnit& U) override {
80    Queue.push_back(U);
81  }
82
83  WorkListUnit dequeue() override {
84    WorkListUnit U = Queue.front();
85    Queue.pop_front();
86    return U;
87  }
88
89  bool visitItemsInWorkList(Visitor &V) override {
90    for (std::deque<WorkListUnit>::iterator
91         I = Queue.begin(), E = Queue.end(); I != E; ++I) {
92      if (V.visit(*I))
93        return true;
94    }
95    return false;
96  }
97};
98
99} // end anonymous namespace
100
101// Place the dstor for WorkList here because it contains virtual member
102// functions, and we the code for the dstor generated in one compilation unit.
103WorkList::~WorkList() {}
104
105WorkList *WorkList::makeDFS() { return new DFS(); }
106WorkList *WorkList::makeBFS() { return new BFS(); }
107
108namespace {
109  class BFSBlockDFSContents : public WorkList {
110    std::deque<WorkListUnit> Queue;
111    SmallVector<WorkListUnit,20> Stack;
112  public:
113    bool hasWork() const override {
114      return !Queue.empty() || !Stack.empty();
115    }
116
117    void enqueue(const WorkListUnit& U) override {
118      if (U.getNode()->getLocation().getAs<BlockEntrance>())
119        Queue.push_front(U);
120      else
121        Stack.push_back(U);
122    }
123
124    WorkListUnit dequeue() override {
125      // Process all basic blocks to completion.
126      if (!Stack.empty()) {
127        const WorkListUnit& U = Stack.back();
128        Stack.pop_back(); // This technically "invalidates" U, but we are fine.
129        return U;
130      }
131
132      assert(!Queue.empty());
133      // Don't use const reference.  The subsequent pop_back() might make it
134      // unsafe.
135      WorkListUnit U = Queue.front();
136      Queue.pop_front();
137      return U;
138    }
139    bool visitItemsInWorkList(Visitor &V) override {
140      for (SmallVectorImpl<WorkListUnit>::iterator
141           I = Stack.begin(), E = Stack.end(); I != E; ++I) {
142        if (V.visit(*I))
143          return true;
144      }
145      for (std::deque<WorkListUnit>::iterator
146           I = Queue.begin(), E = Queue.end(); I != E; ++I) {
147        if (V.visit(*I))
148          return true;
149      }
150      return false;
151    }
152
153  };
154} // end anonymous namespace
155
156WorkList* WorkList::makeBFSBlockDFSContents() {
157  return new BFSBlockDFSContents();
158}
159
160//===----------------------------------------------------------------------===//
161// Core analysis engine.
162//===----------------------------------------------------------------------===//
163
164/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
165bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
166                                   ProgramStateRef InitState) {
167
168  if (G.num_roots() == 0) { // Initialize the analysis by constructing
169    // the root if none exists.
170
171    const CFGBlock *Entry = &(L->getCFG()->getEntry());
172
173    assert (Entry->empty() &&
174            "Entry block must be empty.");
175
176    assert (Entry->succ_size() == 1 &&
177            "Entry block must have 1 successor.");
178
179    // Mark the entry block as visited.
180    FunctionSummaries->markVisitedBasicBlock(Entry->getBlockID(),
181                                             L->getDecl(),
182                                             L->getCFG()->getNumBlockIDs());
183
184    // Get the solitary successor.
185    const CFGBlock *Succ = *(Entry->succ_begin());
186
187    // Construct an edge representing the
188    // starting location in the function.
189    BlockEdge StartLoc(Entry, Succ, L);
190
191    // Set the current block counter to being empty.
192    WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
193
194    if (!InitState)
195      InitState = SubEng.getInitialState(L);
196
197    bool IsNew;
198    ExplodedNode *Node = G.getNode(StartLoc, InitState, false, &IsNew);
199    assert (IsNew);
200    G.addRoot(Node);
201
202    NodeBuilderContext BuilderCtx(*this, StartLoc.getDst(), Node);
203    ExplodedNodeSet DstBegin;
204    SubEng.processBeginOfFunction(BuilderCtx, Node, DstBegin, StartLoc);
205
206    enqueue(DstBegin);
207  }
208
209  // Check if we have a steps limit
210  bool UnlimitedSteps = Steps == 0;
211  // Cap our pre-reservation in the event that the user specifies
212  // a very large number of maximum steps.
213  const unsigned PreReservationCap = 4000000;
214  if(!UnlimitedSteps)
215    G.reserve(std::min(Steps,PreReservationCap));
216
217  while (WList->hasWork()) {
218    if (!UnlimitedSteps) {
219      if (Steps == 0) {
220        NumReachedMaxSteps++;
221        break;
222      }
223      --Steps;
224    }
225
226    NumSteps++;
227
228    const WorkListUnit& WU = WList->dequeue();
229
230    // Set the current block counter.
231    WList->setBlockCounter(WU.getBlockCounter());
232
233    // Retrieve the node.
234    ExplodedNode *Node = WU.getNode();
235
236    dispatchWorkItem(Node, Node->getLocation(), WU);
237  }
238  SubEng.processEndWorklist(hasWorkRemaining());
239  return WList->hasWork();
240}
241
242void CoreEngine::dispatchWorkItem(ExplodedNode* Pred, ProgramPoint Loc,
243                                  const WorkListUnit& WU) {
244  // Dispatch on the location type.
245  switch (Loc.getKind()) {
246    case ProgramPoint::BlockEdgeKind:
247      HandleBlockEdge(Loc.castAs<BlockEdge>(), Pred);
248      break;
249
250    case ProgramPoint::BlockEntranceKind:
251      HandleBlockEntrance(Loc.castAs<BlockEntrance>(), Pred);
252      break;
253
254    case ProgramPoint::BlockExitKind:
255      assert (false && "BlockExit location never occur in forward analysis.");
256      break;
257
258    case ProgramPoint::CallEnterKind: {
259      HandleCallEnter(Loc.castAs<CallEnter>(), Pred);
260      break;
261    }
262
263    case ProgramPoint::CallExitBeginKind:
264      SubEng.processCallExit(Pred);
265      break;
266
267    case ProgramPoint::EpsilonKind: {
268      assert(Pred->hasSinglePred() &&
269             "Assume epsilon has exactly one predecessor by construction");
270      ExplodedNode *PNode = Pred->getFirstPred();
271      dispatchWorkItem(Pred, PNode->getLocation(), WU);
272      break;
273    }
274    default:
275      assert(Loc.getAs<PostStmt>() ||
276             Loc.getAs<PostInitializer>() ||
277             Loc.getAs<PostImplicitCall>() ||
278             Loc.getAs<CallExitEnd>());
279      HandlePostStmt(WU.getBlock(), WU.getIndex(), Pred);
280      break;
281  }
282}
283
284bool CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
285                                                 unsigned Steps,
286                                                 ProgramStateRef InitState,
287                                                 ExplodedNodeSet &Dst) {
288  bool DidNotFinish = ExecuteWorkList(L, Steps, InitState);
289  for (ExplodedGraph::eop_iterator I = G.eop_begin(), E = G.eop_end(); I != E;
290       ++I) {
291    Dst.Add(*I);
292  }
293  return DidNotFinish;
294}
295
296void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
297
298  const CFGBlock *Blk = L.getDst();
299  NodeBuilderContext BuilderCtx(*this, Blk, Pred);
300
301  // Mark this block as visited.
302  const LocationContext *LC = Pred->getLocationContext();
303  FunctionSummaries->markVisitedBasicBlock(Blk->getBlockID(),
304                                           LC->getDecl(),
305                                           LC->getCFG()->getNumBlockIDs());
306
307  // Check if we are entering the EXIT block.
308  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
309
310    assert (L.getLocationContext()->getCFG()->getExit().size() == 0
311            && "EXIT block cannot contain Stmts.");
312
313    // Process the final state transition.
314    SubEng.processEndOfFunction(BuilderCtx, Pred);
315
316    // This path is done. Don't enqueue any more nodes.
317    return;
318  }
319
320  // Call into the SubEngine to process entering the CFGBlock.
321  ExplodedNodeSet dstNodes;
322  BlockEntrance BE(Blk, Pred->getLocationContext());
323  NodeBuilderWithSinks nodeBuilder(Pred, dstNodes, BuilderCtx, BE);
324  SubEng.processCFGBlockEntrance(L, nodeBuilder, Pred);
325
326  // Auto-generate a node.
327  if (!nodeBuilder.hasGeneratedNodes()) {
328    nodeBuilder.generateNode(Pred->State, Pred);
329  }
330
331  // Enqueue nodes onto the worklist.
332  enqueue(dstNodes);
333}
334
335void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
336                                       ExplodedNode *Pred) {
337
338  // Increment the block counter.
339  const LocationContext *LC = Pred->getLocationContext();
340  unsigned BlockId = L.getBlock()->getBlockID();
341  BlockCounter Counter = WList->getBlockCounter();
342  Counter = BCounterFactory.IncrementCount(Counter, LC->getCurrentStackFrame(),
343                                           BlockId);
344  WList->setBlockCounter(Counter);
345
346  // Process the entrance of the block.
347  if (Optional<CFGElement> E = L.getFirstElement()) {
348    NodeBuilderContext Ctx(*this, L.getBlock(), Pred);
349    SubEng.processCFGElement(*E, Pred, 0, &Ctx);
350  }
351  else
352    HandleBlockExit(L.getBlock(), Pred);
353}
354
355void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
356
357  if (const Stmt *Term = B->getTerminator()) {
358    switch (Term->getStmtClass()) {
359      default:
360        llvm_unreachable("Analysis for this terminator not implemented.");
361
362      case Stmt::CXXBindTemporaryExprClass:
363        HandleCleanupTemporaryBranch(
364            cast<CXXBindTemporaryExpr>(B->getTerminator().getStmt()), B, Pred);
365        return;
366
367      // Model static initializers.
368      case Stmt::DeclStmtClass:
369        HandleStaticInit(cast<DeclStmt>(Term), B, Pred);
370        return;
371
372      case Stmt::BinaryOperatorClass: // '&&' and '||'
373        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
374        return;
375
376      case Stmt::BinaryConditionalOperatorClass:
377      case Stmt::ConditionalOperatorClass:
378        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
379                     Term, B, Pred);
380        return;
381
382        // FIXME: Use constant-folding in CFG construction to simplify this
383        // case.
384
385      case Stmt::ChooseExprClass:
386        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
387        return;
388
389      case Stmt::CXXTryStmtClass: {
390        // Generate a node for each of the successors.
391        // Our logic for EH analysis can certainly be improved.
392        for (CFGBlock::const_succ_iterator it = B->succ_begin(),
393             et = B->succ_end(); it != et; ++it) {
394          if (const CFGBlock *succ = *it) {
395            generateNode(BlockEdge(B, succ, Pred->getLocationContext()),
396                         Pred->State, Pred);
397          }
398        }
399        return;
400      }
401
402      case Stmt::DoStmtClass:
403        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
404        return;
405
406      case Stmt::CXXForRangeStmtClass:
407        HandleBranch(cast<CXXForRangeStmt>(Term)->getCond(), Term, B, Pred);
408        return;
409
410      case Stmt::ForStmtClass:
411        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
412        return;
413
414      case Stmt::ContinueStmtClass:
415      case Stmt::BreakStmtClass:
416      case Stmt::GotoStmtClass:
417        break;
418
419      case Stmt::IfStmtClass:
420        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
421        return;
422
423      case Stmt::IndirectGotoStmtClass: {
424        // Only 1 successor: the indirect goto dispatch block.
425        assert (B->succ_size() == 1);
426
427        IndirectGotoNodeBuilder
428           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
429                   *(B->succ_begin()), this);
430
431        SubEng.processIndirectGoto(builder);
432        return;
433      }
434
435      case Stmt::ObjCForCollectionStmtClass: {
436        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
437        //
438        //  (1) inside a basic block, which represents the binding of the
439        //      'element' variable to a value.
440        //  (2) in a terminator, which represents the branch.
441        //
442        // For (1), subengines will bind a value (i.e., 0 or 1) indicating
443        // whether or not collection contains any more elements.  We cannot
444        // just test to see if the element is nil because a container can
445        // contain nil elements.
446        HandleBranch(Term, Term, B, Pred);
447        return;
448      }
449
450      case Stmt::SwitchStmtClass: {
451        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
452                                    this);
453
454        SubEng.processSwitch(builder);
455        return;
456      }
457
458      case Stmt::WhileStmtClass:
459        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
460        return;
461    }
462  }
463
464  assert (B->succ_size() == 1 &&
465          "Blocks with no terminator should have at most 1 successor.");
466
467  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
468               Pred->State, Pred);
469}
470
471void CoreEngine::HandleCallEnter(const CallEnter &CE, ExplodedNode *Pred) {
472  NodeBuilderContext BuilderCtx(*this, CE.getEntry(), Pred);
473  SubEng.processCallEnter(BuilderCtx, CE, Pred);
474}
475
476void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
477                                const CFGBlock * B, ExplodedNode *Pred) {
478  assert(B->succ_size() == 2);
479  NodeBuilderContext Ctx(*this, B, Pred);
480  ExplodedNodeSet Dst;
481  SubEng.processBranch(Cond, Term, Ctx, Pred, Dst,
482                       *(B->succ_begin()), *(B->succ_begin()+1));
483  // Enqueue the new frontier onto the worklist.
484  enqueue(Dst);
485}
486
487void CoreEngine::HandleCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,
488                                              const CFGBlock *B,
489                                              ExplodedNode *Pred) {
490  assert(B->succ_size() == 2);
491  NodeBuilderContext Ctx(*this, B, Pred);
492  ExplodedNodeSet Dst;
493  SubEng.processCleanupTemporaryBranch(BTE, Ctx, Pred, Dst, *(B->succ_begin()),
494                                       *(B->succ_begin() + 1));
495  // Enqueue the new frontier onto the worklist.
496  enqueue(Dst);
497}
498
499void CoreEngine::HandleStaticInit(const DeclStmt *DS, const CFGBlock *B,
500                                  ExplodedNode *Pred) {
501  assert(B->succ_size() == 2);
502  NodeBuilderContext Ctx(*this, B, Pred);
503  ExplodedNodeSet Dst;
504  SubEng.processStaticInitializer(DS, Ctx, Pred, Dst,
505                                  *(B->succ_begin()), *(B->succ_begin()+1));
506  // Enqueue the new frontier onto the worklist.
507  enqueue(Dst);
508}
509
510
511void CoreEngine::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
512                                  ExplodedNode *Pred) {
513  assert(B);
514  assert(!B->empty());
515
516  if (StmtIdx == B->size())
517    HandleBlockExit(B, Pred);
518  else {
519    NodeBuilderContext Ctx(*this, B, Pred);
520    SubEng.processCFGElement((*B)[StmtIdx], Pred, StmtIdx, &Ctx);
521  }
522}
523
524/// generateNode - Utility method to generate nodes, hook up successors,
525///  and add nodes to the worklist.
526void CoreEngine::generateNode(const ProgramPoint &Loc,
527                              ProgramStateRef State,
528                              ExplodedNode *Pred) {
529
530  bool IsNew;
531  ExplodedNode *Node = G.getNode(Loc, State, false, &IsNew);
532
533  if (Pred)
534    Node->addPredecessor(Pred, G); // Link 'Node' with its predecessor.
535  else {
536    assert (IsNew);
537    G.addRoot(Node); // 'Node' has no predecessor.  Make it a root.
538  }
539
540  // Only add 'Node' to the worklist if it was freshly generated.
541  if (IsNew) WList->enqueue(Node);
542}
543
544void CoreEngine::enqueueStmtNode(ExplodedNode *N,
545                                 const CFGBlock *Block, unsigned Idx) {
546  assert(Block);
547  assert (!N->isSink());
548
549  // Check if this node entered a callee.
550  if (N->getLocation().getAs<CallEnter>()) {
551    // Still use the index of the CallExpr. It's needed to create the callee
552    // StackFrameContext.
553    WList->enqueue(N, Block, Idx);
554    return;
555  }
556
557  // Do not create extra nodes. Move to the next CFG element.
558  if (N->getLocation().getAs<PostInitializer>() ||
559      N->getLocation().getAs<PostImplicitCall>()) {
560    WList->enqueue(N, Block, Idx+1);
561    return;
562  }
563
564  if (N->getLocation().getAs<EpsilonPoint>()) {
565    WList->enqueue(N, Block, Idx);
566    return;
567  }
568
569  if ((*Block)[Idx].getKind() == CFGElement::NewAllocator) {
570    WList->enqueue(N, Block, Idx+1);
571    return;
572  }
573
574  // At this point, we know we're processing a normal statement.
575  CFGStmt CS = (*Block)[Idx].castAs<CFGStmt>();
576  PostStmt Loc(CS.getStmt(), N->getLocationContext());
577
578  if (Loc == N->getLocation().withTag(nullptr)) {
579    // Note: 'N' should be a fresh node because otherwise it shouldn't be
580    // a member of Deferred.
581    WList->enqueue(N, Block, Idx+1);
582    return;
583  }
584
585  bool IsNew;
586  ExplodedNode *Succ = G.getNode(Loc, N->getState(), false, &IsNew);
587  Succ->addPredecessor(N, G);
588
589  if (IsNew)
590    WList->enqueue(Succ, Block, Idx+1);
591}
592
593ExplodedNode *CoreEngine::generateCallExitBeginNode(ExplodedNode *N) {
594  // Create a CallExitBegin node and enqueue it.
595  const StackFrameContext *LocCtx
596                         = cast<StackFrameContext>(N->getLocationContext());
597
598  // Use the callee location context.
599  CallExitBegin Loc(LocCtx);
600
601  bool isNew;
602  ExplodedNode *Node = G.getNode(Loc, N->getState(), false, &isNew);
603  Node->addPredecessor(N, G);
604  return isNew ? Node : nullptr;
605}
606
607
608void CoreEngine::enqueue(ExplodedNodeSet &Set) {
609  for (ExplodedNodeSet::iterator I = Set.begin(),
610                                 E = Set.end(); I != E; ++I) {
611    WList->enqueue(*I);
612  }
613}
614
615void CoreEngine::enqueue(ExplodedNodeSet &Set,
616                         const CFGBlock *Block, unsigned Idx) {
617  for (ExplodedNodeSet::iterator I = Set.begin(),
618                                 E = Set.end(); I != E; ++I) {
619    enqueueStmtNode(*I, Block, Idx);
620  }
621}
622
623void CoreEngine::enqueueEndOfFunction(ExplodedNodeSet &Set) {
624  for (ExplodedNodeSet::iterator I = Set.begin(), E = Set.end(); I != E; ++I) {
625    ExplodedNode *N = *I;
626    // If we are in an inlined call, generate CallExitBegin node.
627    if (N->getLocationContext()->getParent()) {
628      N = generateCallExitBeginNode(N);
629      if (N)
630        WList->enqueue(N);
631    } else {
632      // TODO: We should run remove dead bindings here.
633      G.addEndOfPath(N);
634      NumPathsExplored++;
635    }
636  }
637}
638
639
640void NodeBuilder::anchor() { }
641
642ExplodedNode* NodeBuilder::generateNodeImpl(const ProgramPoint &Loc,
643                                            ProgramStateRef State,
644                                            ExplodedNode *FromN,
645                                            bool MarkAsSink) {
646  HasGeneratedNodes = true;
647  bool IsNew;
648  ExplodedNode *N = C.Eng.G.getNode(Loc, State, MarkAsSink, &IsNew);
649  N->addPredecessor(FromN, C.Eng.G);
650  Frontier.erase(FromN);
651
652  if (!IsNew)
653    return nullptr;
654
655  if (!MarkAsSink)
656    Frontier.Add(N);
657
658  return N;
659}
660
661void NodeBuilderWithSinks::anchor() { }
662
663StmtNodeBuilder::~StmtNodeBuilder() {
664  if (EnclosingBldr)
665    for (ExplodedNodeSet::iterator I = Frontier.begin(),
666                                   E = Frontier.end(); I != E; ++I )
667      EnclosingBldr->addNodes(*I);
668}
669
670void BranchNodeBuilder::anchor() { }
671
672ExplodedNode *BranchNodeBuilder::generateNode(ProgramStateRef State,
673                                              bool branch,
674                                              ExplodedNode *NodePred) {
675  // If the branch has been marked infeasible we should not generate a node.
676  if (!isFeasible(branch))
677    return nullptr;
678
679  ProgramPoint Loc = BlockEdge(C.Block, branch ? DstT:DstF,
680                               NodePred->getLocationContext());
681  ExplodedNode *Succ = generateNodeImpl(Loc, State, NodePred);
682  return Succ;
683}
684
685ExplodedNode*
686IndirectGotoNodeBuilder::generateNode(const iterator &I,
687                                      ProgramStateRef St,
688                                      bool IsSink) {
689  bool IsNew;
690  ExplodedNode *Succ =
691      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
692                    St, IsSink, &IsNew);
693  Succ->addPredecessor(Pred, Eng.G);
694
695  if (!IsNew)
696    return nullptr;
697
698  if (!IsSink)
699    Eng.WList->enqueue(Succ);
700
701  return Succ;
702}
703
704
705ExplodedNode*
706SwitchNodeBuilder::generateCaseStmtNode(const iterator &I,
707                                        ProgramStateRef St) {
708
709  bool IsNew;
710  ExplodedNode *Succ =
711      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
712                    St, false, &IsNew);
713  Succ->addPredecessor(Pred, Eng.G);
714  if (!IsNew)
715    return nullptr;
716
717  Eng.WList->enqueue(Succ);
718  return Succ;
719}
720
721
722ExplodedNode*
723SwitchNodeBuilder::generateDefaultCaseNode(ProgramStateRef St,
724                                           bool IsSink) {
725  // Get the block for the default case.
726  assert(Src->succ_rbegin() != Src->succ_rend());
727  CFGBlock *DefaultBlock = *Src->succ_rbegin();
728
729  // Sanity check for default blocks that are unreachable and not caught
730  // by earlier stages.
731  if (!DefaultBlock)
732    return nullptr;
733
734  bool IsNew;
735  ExplodedNode *Succ =
736      Eng.G.getNode(BlockEdge(Src, DefaultBlock, Pred->getLocationContext()),
737                    St, IsSink, &IsNew);
738  Succ->addPredecessor(Pred, Eng.G);
739
740  if (!IsNew)
741    return nullptr;
742
743  if (!IsSink)
744    Eng.WList->enqueue(Succ);
745
746  return Succ;
747}
748