CoreEngine.cpp revision 314564 
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/Statistic.h"
22#include "llvm/Support/Casting.h"
23
24using namespace clang;
25using namespace ento;
26
27#define DEBUG_TYPE "CoreEngine"
28
29STATISTIC(NumSteps,
30            "The # of steps executed.");
31STATISTIC(NumReachedMaxSteps,
32            "The # of times we reached the max number of steps.");
33STATISTIC(NumPathsExplored,
34            "The # of paths explored by the analyzer.");
35
36//===----------------------------------------------------------------------===//
37// Worklist classes for exploration of reachable states.
38//===----------------------------------------------------------------------===//
39
40WorkList::Visitor::~Visitor() {}
41
42namespace {
43class DFS : public WorkList {
44  SmallVector<WorkListUnit,20> Stack;
45public:
46  bool hasWork() const override {
47    return !Stack.empty();
48  }
49
50  void enqueue(const WorkListUnit& U) override {
51    Stack.push_back(U);
52  }
53
54  WorkListUnit dequeue() override {
55    assert (!Stack.empty());
56    const WorkListUnit& U = Stack.back();
57    Stack.pop_back(); // This technically "invalidates" U, but we are fine.
58    return U;
59  }
60
61  bool visitItemsInWorkList(Visitor &V) override {
62    for (SmallVectorImpl<WorkListUnit>::iterator
63         I = Stack.begin(), E = Stack.end(); I != E; ++I) {
64      if (V.visit(*I))
65        return true;
66    }
67    return false;
68  }
69};
70
71class BFS : public WorkList {
72  std::deque<WorkListUnit> Queue;
73public:
74  bool hasWork() const override {
75    return !Queue.empty();
76  }
77
78  void enqueue(const WorkListUnit& U) override {
79    Queue.push_back(U);
80  }
81
82  WorkListUnit dequeue() override {
83    WorkListUnit U = Queue.front();
84    Queue.pop_front();
85    return U;
86  }
87
88  bool visitItemsInWorkList(Visitor &V) override {
89    for (std::deque<WorkListUnit>::iterator
90         I = Queue.begin(), E = Queue.end(); I != E; ++I) {
91      if (V.visit(*I))
92        return true;
93    }
94    return false;
95  }
96};
97
98} // end anonymous namespace
99
100// Place the dstor for WorkList here because it contains virtual member
101// functions, and we the code for the dstor generated in one compilation unit.
102WorkList::~WorkList() {}
103
104WorkList *WorkList::makeDFS() { return new DFS(); }
105WorkList *WorkList::makeBFS() { return new BFS(); }
106
107namespace {
108  class BFSBlockDFSContents : public WorkList {
109    std::deque<WorkListUnit> Queue;
110    SmallVector<WorkListUnit,20> Stack;
111  public:
112    bool hasWork() const override {
113      return !Queue.empty() || !Stack.empty();
114    }
115
116    void enqueue(const WorkListUnit& U) override {
117      if (U.getNode()->getLocation().getAs<BlockEntrance>())
118        Queue.push_front(U);
119      else
120        Stack.push_back(U);
121    }
122
123    WorkListUnit dequeue() override {
124      // Process all basic blocks to completion.
125      if (!Stack.empty()) {
126        const WorkListUnit& U = Stack.back();
127        Stack.pop_back(); // This technically "invalidates" U, but we are fine.
128        return U;
129      }
130
131      assert(!Queue.empty());
132      // Don't use const reference.  The subsequent pop_back() might make it
133      // unsafe.
134      WorkListUnit U = Queue.front();
135      Queue.pop_front();
136      return U;
137    }
138    bool visitItemsInWorkList(Visitor &V) override {
139      for (SmallVectorImpl<WorkListUnit>::iterator
140           I = Stack.begin(), E = Stack.end(); I != E; ++I) {
141        if (V.visit(*I))
142          return true;
143      }
144      for (std::deque<WorkListUnit>::iterator
145           I = Queue.begin(), E = Queue.end(); I != E; ++I) {
146        if (V.visit(*I))
147          return true;
148      }
149      return false;
150    }
151
152  };
153} // end anonymous namespace
154
155WorkList* WorkList::makeBFSBlockDFSContents() {
156  return new BFSBlockDFSContents();
157}
158
159//===----------------------------------------------------------------------===//
160// Core analysis engine.
161//===----------------------------------------------------------------------===//
162
163/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
164bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
165                                   ProgramStateRef InitState) {
166
167  if (G.num_roots() == 0) { // Initialize the analysis by constructing
168    // the root if none exists.
169
170    const CFGBlock *Entry = &(L->getCFG()->getEntry());
171
172    assert (Entry->empty() &&
173            "Entry block must be empty.");
174
175    assert (Entry->succ_size() == 1 &&
176            "Entry block must have 1 successor.");
177
178    // Mark the entry block as visited.
179    FunctionSummaries->markVisitedBasicBlock(Entry->getBlockID(),
180                                             L->getDecl(),
181                                             L->getCFG()->getNumBlockIDs());
182
183    // Get the solitary successor.
184    const CFGBlock *Succ = *(Entry->succ_begin());
185
186    // Construct an edge representing the
187    // starting location in the function.
188    BlockEdge StartLoc(Entry, Succ, L);
189
190    // Set the current block counter to being empty.
191    WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
192
193    if (!InitState)
194      InitState = SubEng.getInitialState(L);
195
196    bool IsNew;
197    ExplodedNode *Node = G.getNode(StartLoc, InitState, false, &IsNew);
198    assert (IsNew);
199    G.addRoot(Node);
200
201    NodeBuilderContext BuilderCtx(*this, StartLoc.getDst(), Node);
202    ExplodedNodeSet DstBegin;
203    SubEng.processBeginOfFunction(BuilderCtx, Node, DstBegin, StartLoc);
204
205    enqueue(DstBegin);
206  }
207
208  // Check if we have a steps limit
209  bool UnlimitedSteps = Steps == 0;
210  // Cap our pre-reservation in the event that the user specifies
211  // a very large number of maximum steps.
212  const unsigned PreReservationCap = 4000000;
213  if(!UnlimitedSteps)
214    G.reserve(std::min(Steps,PreReservationCap));
215
216  while (WList->hasWork()) {
217    if (!UnlimitedSteps) {
218      if (Steps == 0) {
219        NumReachedMaxSteps++;
220        break;
221      }
222      --Steps;
223    }
224
225    NumSteps++;
226
227    const WorkListUnit& WU = WList->dequeue();
228
229    // Set the current block counter.
230    WList->setBlockCounter(WU.getBlockCounter());
231
232    // Retrieve the node.
233    ExplodedNode *Node = WU.getNode();
234
235    dispatchWorkItem(Node, Node->getLocation(), WU);
236  }
237  SubEng.processEndWorklist(hasWorkRemaining());
238  return WList->hasWork();
239}
240
241void CoreEngine::dispatchWorkItem(ExplodedNode* Pred, ProgramPoint Loc,
242                                  const WorkListUnit& WU) {
243  // Dispatch on the location type.
244  switch (Loc.getKind()) {
245    case ProgramPoint::BlockEdgeKind:
246      HandleBlockEdge(Loc.castAs<BlockEdge>(), Pred);
247      break;
248
249    case ProgramPoint::BlockEntranceKind:
250      HandleBlockEntrance(Loc.castAs<BlockEntrance>(), Pred);
251      break;
252
253    case ProgramPoint::BlockExitKind:
254      assert (false && "BlockExit location never occur in forward analysis.");
255      break;
256
257    case ProgramPoint::CallEnterKind: {
258      HandleCallEnter(Loc.castAs<CallEnter>(), Pred);
259      break;
260    }
261
262    case ProgramPoint::CallExitBeginKind:
263      SubEng.processCallExit(Pred);
264      break;
265
266    case ProgramPoint::EpsilonKind: {
267      assert(Pred->hasSinglePred() &&
268             "Assume epsilon has exactly one predecessor by construction");
269      ExplodedNode *PNode = Pred->getFirstPred();
270      dispatchWorkItem(Pred, PNode->getLocation(), WU);
271      break;
272    }
273    default:
274      assert(Loc.getAs<PostStmt>() ||
275             Loc.getAs<PostInitializer>() ||
276             Loc.getAs<PostImplicitCall>() ||
277             Loc.getAs<CallExitEnd>());
278      HandlePostStmt(WU.getBlock(), WU.getIndex(), Pred);
279      break;
280  }
281}
282
283bool CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
284                                                 unsigned Steps,
285                                                 ProgramStateRef InitState,
286                                                 ExplodedNodeSet &Dst) {
287  bool DidNotFinish = ExecuteWorkList(L, Steps, InitState);
288  for (ExplodedGraph::eop_iterator I = G.eop_begin(), E = G.eop_end(); I != E;
289       ++I) {
290    Dst.Add(*I);
291  }
292  return DidNotFinish;
293}
294
295void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
296
297  const CFGBlock *Blk = L.getDst();
298  NodeBuilderContext BuilderCtx(*this, Blk, Pred);
299
300  // Mark this block as visited.
301  const LocationContext *LC = Pred->getLocationContext();
302  FunctionSummaries->markVisitedBasicBlock(Blk->getBlockID(),
303                                           LC->getDecl(),
304                                           LC->getCFG()->getNumBlockIDs());
305
306  // Check if we are entering the EXIT block.
307  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
308
309    assert (L.getLocationContext()->getCFG()->getExit().size() == 0
310            && "EXIT block cannot contain Stmts.");
311
312    // Get return statement..
313    const ReturnStmt *RS = nullptr;
314    if (!L.getSrc()->empty()) {
315      if (Optional<CFGStmt> LastStmt = L.getSrc()->back().getAs<CFGStmt>()) {
316        if ((RS = dyn_cast<ReturnStmt>(LastStmt->getStmt()))) {
317          if (!RS->getRetValue())
318            RS = nullptr;
319        }
320      }
321    }
322
323    // Process the final state transition.
324    SubEng.processEndOfFunction(BuilderCtx, Pred, RS);
325
326    // This path is done. Don't enqueue any more nodes.
327    return;
328  }
329
330  // Call into the SubEngine to process entering the CFGBlock.
331  ExplodedNodeSet dstNodes;
332  BlockEntrance BE(Blk, Pred->getLocationContext());
333  NodeBuilderWithSinks nodeBuilder(Pred, dstNodes, BuilderCtx, BE);
334  SubEng.processCFGBlockEntrance(L, nodeBuilder, Pred);
335
336  // Auto-generate a node.
337  if (!nodeBuilder.hasGeneratedNodes()) {
338    nodeBuilder.generateNode(Pred->State, Pred);
339  }
340
341  // Enqueue nodes onto the worklist.
342  enqueue(dstNodes);
343}
344
345void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
346                                       ExplodedNode *Pred) {
347
348  // Increment the block counter.
349  const LocationContext *LC = Pred->getLocationContext();
350  unsigned BlockId = L.getBlock()->getBlockID();
351  BlockCounter Counter = WList->getBlockCounter();
352  Counter = BCounterFactory.IncrementCount(Counter, LC->getCurrentStackFrame(),
353                                           BlockId);
354  WList->setBlockCounter(Counter);
355
356  // Process the entrance of the block.
357  if (Optional<CFGElement> E = L.getFirstElement()) {
358    NodeBuilderContext Ctx(*this, L.getBlock(), Pred);
359    SubEng.processCFGElement(*E, Pred, 0, &Ctx);
360  }
361  else
362    HandleBlockExit(L.getBlock(), Pred);
363}
364
365void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
366
367  if (const Stmt *Term = B->getTerminator()) {
368    switch (Term->getStmtClass()) {
369      default:
370        llvm_unreachable("Analysis for this terminator not implemented.");
371
372      case Stmt::CXXBindTemporaryExprClass:
373        HandleCleanupTemporaryBranch(
374            cast<CXXBindTemporaryExpr>(B->getTerminator().getStmt()), B, Pred);
375        return;
376
377      // Model static initializers.
378      case Stmt::DeclStmtClass:
379        HandleStaticInit(cast<DeclStmt>(Term), B, Pred);
380        return;
381
382      case Stmt::BinaryOperatorClass: // '&&' and '||'
383        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
384        return;
385
386      case Stmt::BinaryConditionalOperatorClass:
387      case Stmt::ConditionalOperatorClass:
388        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
389                     Term, B, Pred);
390        return;
391
392        // FIXME: Use constant-folding in CFG construction to simplify this
393        // case.
394
395      case Stmt::ChooseExprClass:
396        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
397        return;
398
399      case Stmt::CXXTryStmtClass: {
400        // Generate a node for each of the successors.
401        // Our logic for EH analysis can certainly be improved.
402        for (CFGBlock::const_succ_iterator it = B->succ_begin(),
403             et = B->succ_end(); it != et; ++it) {
404          if (const CFGBlock *succ = *it) {
405            generateNode(BlockEdge(B, succ, Pred->getLocationContext()),
406                         Pred->State, Pred);
407          }
408        }
409        return;
410      }
411
412      case Stmt::DoStmtClass:
413        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
414        return;
415
416      case Stmt::CXXForRangeStmtClass:
417        HandleBranch(cast<CXXForRangeStmt>(Term)->getCond(), Term, B, Pred);
418        return;
419
420      case Stmt::ForStmtClass:
421        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
422        return;
423
424      case Stmt::ContinueStmtClass:
425      case Stmt::BreakStmtClass:
426      case Stmt::GotoStmtClass:
427        break;
428
429      case Stmt::IfStmtClass:
430        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
431        return;
432
433      case Stmt::IndirectGotoStmtClass: {
434        // Only 1 successor: the indirect goto dispatch block.
435        assert (B->succ_size() == 1);
436
437        IndirectGotoNodeBuilder
438           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
439                   *(B->succ_begin()), this);
440
441        SubEng.processIndirectGoto(builder);
442        return;
443      }
444
445      case Stmt::ObjCForCollectionStmtClass: {
446        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
447        //
448        //  (1) inside a basic block, which represents the binding of the
449        //      'element' variable to a value.
450        //  (2) in a terminator, which represents the branch.
451        //
452        // For (1), subengines will bind a value (i.e., 0 or 1) indicating
453        // whether or not collection contains any more elements.  We cannot
454        // just test to see if the element is nil because a container can
455        // contain nil elements.
456        HandleBranch(Term, Term, B, Pred);
457        return;
458      }
459
460      case Stmt::SwitchStmtClass: {
461        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
462                                    this);
463
464        SubEng.processSwitch(builder);
465        return;
466      }
467
468      case Stmt::WhileStmtClass:
469        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
470        return;
471    }
472  }
473
474  assert (B->succ_size() == 1 &&
475          "Blocks with no terminator should have at most 1 successor.");
476
477  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
478               Pred->State, Pred);
479}
480
481void CoreEngine::HandleCallEnter(const CallEnter &CE, ExplodedNode *Pred) {
482  NodeBuilderContext BuilderCtx(*this, CE.getEntry(), Pred);
483  SubEng.processCallEnter(BuilderCtx, CE, Pred);
484}
485
486void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
487                                const CFGBlock * B, ExplodedNode *Pred) {
488  assert(B->succ_size() == 2);
489  NodeBuilderContext Ctx(*this, B, Pred);
490  ExplodedNodeSet Dst;
491  SubEng.processBranch(Cond, Term, Ctx, Pred, Dst,
492                       *(B->succ_begin()), *(B->succ_begin()+1));
493  // Enqueue the new frontier onto the worklist.
494  enqueue(Dst);
495}
496
497void CoreEngine::HandleCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,
498                                              const CFGBlock *B,
499                                              ExplodedNode *Pred) {
500  assert(B->succ_size() == 2);
501  NodeBuilderContext Ctx(*this, B, Pred);
502  ExplodedNodeSet Dst;
503  SubEng.processCleanupTemporaryBranch(BTE, Ctx, Pred, Dst, *(B->succ_begin()),
504                                       *(B->succ_begin() + 1));
505  // Enqueue the new frontier onto the worklist.
506  enqueue(Dst);
507}
508
509void CoreEngine::HandleStaticInit(const DeclStmt *DS, const CFGBlock *B,
510                                  ExplodedNode *Pred) {
511  assert(B->succ_size() == 2);
512  NodeBuilderContext Ctx(*this, B, Pred);
513  ExplodedNodeSet Dst;
514  SubEng.processStaticInitializer(DS, Ctx, Pred, Dst,
515                                  *(B->succ_begin()), *(B->succ_begin()+1));
516  // Enqueue the new frontier onto the worklist.
517  enqueue(Dst);
518}
519
520
521void CoreEngine::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
522                                  ExplodedNode *Pred) {
523  assert(B);
524  assert(!B->empty());
525
526  if (StmtIdx == B->size())
527    HandleBlockExit(B, Pred);
528  else {
529    NodeBuilderContext Ctx(*this, B, Pred);
530    SubEng.processCFGElement((*B)[StmtIdx], Pred, StmtIdx, &Ctx);
531  }
532}
533
534/// generateNode - Utility method to generate nodes, hook up successors,
535///  and add nodes to the worklist.
536void CoreEngine::generateNode(const ProgramPoint &Loc,
537                              ProgramStateRef State,
538                              ExplodedNode *Pred) {
539
540  bool IsNew;
541  ExplodedNode *Node = G.getNode(Loc, State, false, &IsNew);
542
543  if (Pred)
544    Node->addPredecessor(Pred, G); // Link 'Node' with its predecessor.
545  else {
546    assert (IsNew);
547    G.addRoot(Node); // 'Node' has no predecessor.  Make it a root.
548  }
549
550  // Only add 'Node' to the worklist if it was freshly generated.
551  if (IsNew) WList->enqueue(Node);
552}
553
554void CoreEngine::enqueueStmtNode(ExplodedNode *N,
555                                 const CFGBlock *Block, unsigned Idx) {
556  assert(Block);
557  assert (!N->isSink());
558
559  // Check if this node entered a callee.
560  if (N->getLocation().getAs<CallEnter>()) {
561    // Still use the index of the CallExpr. It's needed to create the callee
562    // StackFrameContext.
563    WList->enqueue(N, Block, Idx);
564    return;
565  }
566
567  // Do not create extra nodes. Move to the next CFG element.
568  if (N->getLocation().getAs<PostInitializer>() ||
569      N->getLocation().getAs<PostImplicitCall>()) {
570    WList->enqueue(N, Block, Idx+1);
571    return;
572  }
573
574  if (N->getLocation().getAs<EpsilonPoint>()) {
575    WList->enqueue(N, Block, Idx);
576    return;
577  }
578
579  if ((*Block)[Idx].getKind() == CFGElement::NewAllocator) {
580    WList->enqueue(N, Block, Idx+1);
581    return;
582  }
583
584  // At this point, we know we're processing a normal statement.
585  CFGStmt CS = (*Block)[Idx].castAs<CFGStmt>();
586  PostStmt Loc(CS.getStmt(), N->getLocationContext());
587
588  if (Loc == N->getLocation().withTag(nullptr)) {
589    // Note: 'N' should be a fresh node because otherwise it shouldn't be
590    // a member of Deferred.
591    WList->enqueue(N, Block, Idx+1);
592    return;
593  }
594
595  bool IsNew;
596  ExplodedNode *Succ = G.getNode(Loc, N->getState(), false, &IsNew);
597  Succ->addPredecessor(N, G);
598
599  if (IsNew)
600    WList->enqueue(Succ, Block, Idx+1);
601}
602
603ExplodedNode *CoreEngine::generateCallExitBeginNode(ExplodedNode *N,
604                                                    const ReturnStmt *RS) {
605  // Create a CallExitBegin node and enqueue it.
606  const StackFrameContext *LocCtx
607                         = cast<StackFrameContext>(N->getLocationContext());
608
609  // Use the callee location context.
610  CallExitBegin Loc(LocCtx, RS);
611
612  bool isNew;
613  ExplodedNode *Node = G.getNode(Loc, N->getState(), false, &isNew);
614  Node->addPredecessor(N, G);
615  return isNew ? Node : nullptr;
616}
617
618
619void CoreEngine::enqueue(ExplodedNodeSet &Set) {
620  for (ExplodedNodeSet::iterator I = Set.begin(),
621                                 E = Set.end(); I != E; ++I) {
622    WList->enqueue(*I);
623  }
624}
625
626void CoreEngine::enqueue(ExplodedNodeSet &Set,
627                         const CFGBlock *Block, unsigned Idx) {
628  for (ExplodedNodeSet::iterator I = Set.begin(),
629                                 E = Set.end(); I != E; ++I) {
630    enqueueStmtNode(*I, Block, Idx);
631  }
632}
633
634void CoreEngine::enqueueEndOfFunction(ExplodedNodeSet &Set, const ReturnStmt *RS) {
635  for (ExplodedNodeSet::iterator I = Set.begin(), E = Set.end(); I != E; ++I) {
636    ExplodedNode *N = *I;
637    // If we are in an inlined call, generate CallExitBegin node.
638    if (N->getLocationContext()->getParent()) {
639      N = generateCallExitBeginNode(N, RS);
640      if (N)
641        WList->enqueue(N);
642    } else {
643      // TODO: We should run remove dead bindings here.
644      G.addEndOfPath(N);
645      NumPathsExplored++;
646    }
647  }
648}
649
650
651void NodeBuilder::anchor() { }
652
653ExplodedNode* NodeBuilder::generateNodeImpl(const ProgramPoint &Loc,
654                                            ProgramStateRef State,
655                                            ExplodedNode *FromN,
656                                            bool MarkAsSink) {
657  HasGeneratedNodes = true;
658  bool IsNew;
659  ExplodedNode *N = C.Eng.G.getNode(Loc, State, MarkAsSink, &IsNew);
660  N->addPredecessor(FromN, C.Eng.G);
661  Frontier.erase(FromN);
662
663  if (!IsNew)
664    return nullptr;
665
666  if (!MarkAsSink)
667    Frontier.Add(N);
668
669  return N;
670}
671
672void NodeBuilderWithSinks::anchor() { }
673
674StmtNodeBuilder::~StmtNodeBuilder() {
675  if (EnclosingBldr)
676    for (ExplodedNodeSet::iterator I = Frontier.begin(),
677                                   E = Frontier.end(); I != E; ++I )
678      EnclosingBldr->addNodes(*I);
679}
680
681void BranchNodeBuilder::anchor() { }
682
683ExplodedNode *BranchNodeBuilder::generateNode(ProgramStateRef State,
684                                              bool branch,
685                                              ExplodedNode *NodePred) {
686  // If the branch has been marked infeasible we should not generate a node.
687  if (!isFeasible(branch))
688    return nullptr;
689
690  ProgramPoint Loc = BlockEdge(C.Block, branch ? DstT:DstF,
691                               NodePred->getLocationContext());
692  ExplodedNode *Succ = generateNodeImpl(Loc, State, NodePred);
693  return Succ;
694}
695
696ExplodedNode*
697IndirectGotoNodeBuilder::generateNode(const iterator &I,
698                                      ProgramStateRef St,
699                                      bool IsSink) {
700  bool IsNew;
701  ExplodedNode *Succ =
702      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
703                    St, IsSink, &IsNew);
704  Succ->addPredecessor(Pred, Eng.G);
705
706  if (!IsNew)
707    return nullptr;
708
709  if (!IsSink)
710    Eng.WList->enqueue(Succ);
711
712  return Succ;
713}
714
715
716ExplodedNode*
717SwitchNodeBuilder::generateCaseStmtNode(const iterator &I,
718                                        ProgramStateRef St) {
719
720  bool IsNew;
721  ExplodedNode *Succ =
722      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
723                    St, false, &IsNew);
724  Succ->addPredecessor(Pred, Eng.G);
725  if (!IsNew)
726    return nullptr;
727
728  Eng.WList->enqueue(Succ);
729  return Succ;
730}
731
732
733ExplodedNode*
734SwitchNodeBuilder::generateDefaultCaseNode(ProgramStateRef St,
735                                           bool IsSink) {
736  // Get the block for the default case.
737  assert(Src->succ_rbegin() != Src->succ_rend());
738  CFGBlock *DefaultBlock = *Src->succ_rbegin();
739
740  // Sanity check for default blocks that are unreachable and not caught
741  // by earlier stages.
742  if (!DefaultBlock)
743    return nullptr;
744
745  bool IsNew;
746  ExplodedNode *Succ =
747      Eng.G.getNode(BlockEdge(Src, DefaultBlock, Pred->getLocationContext()),
748                    St, IsSink, &IsNew);
749  Succ->addPredecessor(Pred, Eng.G);
750
751  if (!IsNew)
752    return nullptr;
753
754  if (!IsSink)
755    Eng.WList->enqueue(Succ);
756
757  return Succ;
758}
759