1//===- CoreEngine.cpp - Path-Sensitive Dataflow Engine --------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file defines a generic engine for intraprocedural, path-sensitive,
10//  dataflow analysis via graph reachability engine.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/StaticAnalyzer/Core/PathSensitive/CoreEngine.h"
15#include "clang/AST/Expr.h"
16#include "clang/AST/ExprCXX.h"
17#include "clang/AST/Stmt.h"
18#include "clang/AST/StmtCXX.h"
19#include "clang/Analysis/AnalysisDeclContext.h"
20#include "clang/Analysis/CFG.h"
21#include "clang/Analysis/ProgramPoint.h"
22#include "clang/Basic/LLVM.h"
23#include "clang/StaticAnalyzer/Core/AnalyzerOptions.h"
24#include "clang/StaticAnalyzer/Core/PathSensitive/BlockCounter.h"
25#include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
26#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
27#include "clang/StaticAnalyzer/Core/PathSensitive/FunctionSummary.h"
28#include "clang/StaticAnalyzer/Core/PathSensitive/WorkList.h"
29#include "llvm/ADT/STLExtras.h"
30#include "llvm/ADT/Statistic.h"
31#include "llvm/Support/Casting.h"
32#include "llvm/Support/ErrorHandling.h"
33#include <algorithm>
34#include <cassert>
35#include <memory>
36#include <optional>
37#include <utility>
38
39using namespace clang;
40using namespace ento;
41
42#define DEBUG_TYPE "CoreEngine"
43
44STATISTIC(NumSteps,
45            "The # of steps executed.");
46STATISTIC(NumSTUSteps, "The # of STU steps executed.");
47STATISTIC(NumCTUSteps, "The # of CTU steps executed.");
48STATISTIC(NumReachedMaxSteps,
49            "The # of times we reached the max number of steps.");
50STATISTIC(NumPathsExplored,
51            "The # of paths explored by the analyzer.");
52
53//===----------------------------------------------------------------------===//
54// Core analysis engine.
55//===----------------------------------------------------------------------===//
56
57static std::unique_ptr<WorkList> generateWorkList(AnalyzerOptions &Opts) {
58  switch (Opts.getExplorationStrategy()) {
59    case ExplorationStrategyKind::DFS:
60      return WorkList::makeDFS();
61    case ExplorationStrategyKind::BFS:
62      return WorkList::makeBFS();
63    case ExplorationStrategyKind::BFSBlockDFSContents:
64      return WorkList::makeBFSBlockDFSContents();
65    case ExplorationStrategyKind::UnexploredFirst:
66      return WorkList::makeUnexploredFirst();
67    case ExplorationStrategyKind::UnexploredFirstQueue:
68      return WorkList::makeUnexploredFirstPriorityQueue();
69    case ExplorationStrategyKind::UnexploredFirstLocationQueue:
70      return WorkList::makeUnexploredFirstPriorityLocationQueue();
71  }
72  llvm_unreachable("Unknown AnalyzerOptions::ExplorationStrategyKind");
73}
74
75CoreEngine::CoreEngine(ExprEngine &exprengine, FunctionSummariesTy *FS,
76                       AnalyzerOptions &Opts)
77    : ExprEng(exprengine), WList(generateWorkList(Opts)),
78      CTUWList(Opts.IsNaiveCTUEnabled ? generateWorkList(Opts) : nullptr),
79      BCounterFactory(G.getAllocator()), FunctionSummaries(FS) {}
80
81void CoreEngine::setBlockCounter(BlockCounter C) {
82  WList->setBlockCounter(C);
83  if (CTUWList)
84    CTUWList->setBlockCounter(C);
85}
86
87/// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
88bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned MaxSteps,
89                                 ProgramStateRef InitState) {
90  if (G.num_roots() == 0) { // Initialize the analysis by constructing
91    // the root if none exists.
92
93    const CFGBlock *Entry = &(L->getCFG()->getEntry());
94
95    assert(Entry->empty() && "Entry block must be empty.");
96
97    assert(Entry->succ_size() == 1 && "Entry block must have 1 successor.");
98
99    // Mark the entry block as visited.
100    FunctionSummaries->markVisitedBasicBlock(Entry->getBlockID(),
101                                             L->getDecl(),
102                                             L->getCFG()->getNumBlockIDs());
103
104    // Get the solitary successor.
105    const CFGBlock *Succ = *(Entry->succ_begin());
106
107    // Construct an edge representing the
108    // starting location in the function.
109    BlockEdge StartLoc(Entry, Succ, L);
110
111    // Set the current block counter to being empty.
112    setBlockCounter(BCounterFactory.GetEmptyCounter());
113
114    if (!InitState)
115      InitState = ExprEng.getInitialState(L);
116
117    bool IsNew;
118    ExplodedNode *Node = G.getNode(StartLoc, InitState, false, &IsNew);
119    assert(IsNew);
120    G.addRoot(Node);
121
122    NodeBuilderContext BuilderCtx(*this, StartLoc.getDst(), Node);
123    ExplodedNodeSet DstBegin;
124    ExprEng.processBeginOfFunction(BuilderCtx, Node, DstBegin, StartLoc);
125
126    enqueue(DstBegin);
127  }
128
129  // Check if we have a steps limit
130  bool UnlimitedSteps = MaxSteps == 0;
131
132  // Cap our pre-reservation in the event that the user specifies
133  // a very large number of maximum steps.
134  const unsigned PreReservationCap = 4000000;
135  if(!UnlimitedSteps)
136    G.reserve(std::min(MaxSteps, PreReservationCap));
137
138  auto ProcessWList = [this, UnlimitedSteps](unsigned MaxSteps) {
139    unsigned Steps = MaxSteps;
140    while (WList->hasWork()) {
141      if (!UnlimitedSteps) {
142        if (Steps == 0) {
143          NumReachedMaxSteps++;
144          break;
145        }
146        --Steps;
147      }
148
149      NumSteps++;
150
151      const WorkListUnit &WU = WList->dequeue();
152
153      // Set the current block counter.
154      setBlockCounter(WU.getBlockCounter());
155
156      // Retrieve the node.
157      ExplodedNode *Node = WU.getNode();
158
159      dispatchWorkItem(Node, Node->getLocation(), WU);
160    }
161    return MaxSteps - Steps;
162  };
163  const unsigned STUSteps = ProcessWList(MaxSteps);
164
165  if (CTUWList) {
166    NumSTUSteps += STUSteps;
167    const unsigned MinCTUSteps =
168        this->ExprEng.getAnalysisManager().options.CTUMaxNodesMin;
169    const unsigned Pct =
170        this->ExprEng.getAnalysisManager().options.CTUMaxNodesPercentage;
171    unsigned MaxCTUSteps = std::max(STUSteps * Pct / 100, MinCTUSteps);
172
173    WList = std::move(CTUWList);
174    const unsigned CTUSteps = ProcessWList(MaxCTUSteps);
175    NumCTUSteps += CTUSteps;
176  }
177
178  ExprEng.processEndWorklist();
179  return WList->hasWork();
180}
181
182void CoreEngine::dispatchWorkItem(ExplodedNode* Pred, ProgramPoint Loc,
183                                  const WorkListUnit& WU) {
184  // Dispatch on the location type.
185  switch (Loc.getKind()) {
186    case ProgramPoint::BlockEdgeKind:
187      HandleBlockEdge(Loc.castAs<BlockEdge>(), Pred);
188      break;
189
190    case ProgramPoint::BlockEntranceKind:
191      HandleBlockEntrance(Loc.castAs<BlockEntrance>(), Pred);
192      break;
193
194    case ProgramPoint::BlockExitKind:
195      assert(false && "BlockExit location never occur in forward analysis.");
196      break;
197
198    case ProgramPoint::CallEnterKind:
199      HandleCallEnter(Loc.castAs<CallEnter>(), Pred);
200      break;
201
202    case ProgramPoint::CallExitBeginKind:
203      ExprEng.processCallExit(Pred);
204      break;
205
206    case ProgramPoint::EpsilonKind: {
207      assert(Pred->hasSinglePred() &&
208             "Assume epsilon has exactly one predecessor by construction");
209      ExplodedNode *PNode = Pred->getFirstPred();
210      dispatchWorkItem(Pred, PNode->getLocation(), WU);
211      break;
212    }
213    default:
214      assert(Loc.getAs<PostStmt>() ||
215             Loc.getAs<PostInitializer>() ||
216             Loc.getAs<PostImplicitCall>() ||
217             Loc.getAs<CallExitEnd>() ||
218             Loc.getAs<LoopExit>() ||
219             Loc.getAs<PostAllocatorCall>());
220      HandlePostStmt(WU.getBlock(), WU.getIndex(), Pred);
221      break;
222  }
223}
224
225bool CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
226                                                 unsigned Steps,
227                                                 ProgramStateRef InitState,
228                                                 ExplodedNodeSet &Dst) {
229  bool DidNotFinish = ExecuteWorkList(L, Steps, InitState);
230  for (ExplodedGraph::eop_iterator I = G.eop_begin(), E = G.eop_end(); I != E;
231       ++I) {
232    Dst.Add(*I);
233  }
234  return DidNotFinish;
235}
236
237void CoreEngine::HandleBlockEdge(const BlockEdge &L, ExplodedNode *Pred) {
238  const CFGBlock *Blk = L.getDst();
239  NodeBuilderContext BuilderCtx(*this, Blk, Pred);
240
241  // Mark this block as visited.
242  const LocationContext *LC = Pred->getLocationContext();
243  FunctionSummaries->markVisitedBasicBlock(Blk->getBlockID(),
244                                           LC->getDecl(),
245                                           LC->getCFG()->getNumBlockIDs());
246
247  // Display a prunable path note to the user if it's a virtual bases branch
248  // and we're taking the path that skips virtual base constructors.
249  if (L.getSrc()->getTerminator().isVirtualBaseBranch() &&
250      L.getDst() == *L.getSrc()->succ_begin()) {
251    ProgramPoint P = L.withTag(getDataTags().make<NoteTag>(
252        [](BugReporterContext &, PathSensitiveBugReport &) -> std::string {
253          // TODO: Just call out the name of the most derived class
254          // when we know it.
255          return "Virtual base initialization skipped because "
256                 "it has already been handled by the most derived class";
257        },
258        /*IsPrunable=*/true));
259    // Perform the transition.
260    ExplodedNodeSet Dst;
261    NodeBuilder Bldr(Pred, Dst, BuilderCtx);
262    Pred = Bldr.generateNode(P, Pred->getState(), Pred);
263    if (!Pred)
264      return;
265  }
266
267  // Check if we are entering the EXIT block.
268  if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
269    assert(L.getLocationContext()->getCFG()->getExit().empty() &&
270           "EXIT block cannot contain Stmts.");
271
272    // Get return statement..
273    const ReturnStmt *RS = nullptr;
274    if (!L.getSrc()->empty()) {
275      CFGElement LastElement = L.getSrc()->back();
276      if (std::optional<CFGStmt> LastStmt = LastElement.getAs<CFGStmt>()) {
277        RS = dyn_cast<ReturnStmt>(LastStmt->getStmt());
278      } else if (std::optional<CFGAutomaticObjDtor> AutoDtor =
279                     LastElement.getAs<CFGAutomaticObjDtor>()) {
280        RS = dyn_cast<ReturnStmt>(AutoDtor->getTriggerStmt());
281      }
282    }
283
284    // Process the final state transition.
285    ExprEng.processEndOfFunction(BuilderCtx, Pred, RS);
286
287    // This path is done. Don't enqueue any more nodes.
288    return;
289  }
290
291  // Call into the ExprEngine to process entering the CFGBlock.
292  ExplodedNodeSet dstNodes;
293  BlockEntrance BE(Blk, Pred->getLocationContext());
294  NodeBuilderWithSinks nodeBuilder(Pred, dstNodes, BuilderCtx, BE);
295  ExprEng.processCFGBlockEntrance(L, nodeBuilder, Pred);
296
297  // Auto-generate a node.
298  if (!nodeBuilder.hasGeneratedNodes()) {
299    nodeBuilder.generateNode(Pred->State, Pred);
300  }
301
302  // Enqueue nodes onto the worklist.
303  enqueue(dstNodes);
304}
305
306void CoreEngine::HandleBlockEntrance(const BlockEntrance &L,
307                                       ExplodedNode *Pred) {
308  // Increment the block counter.
309  const LocationContext *LC = Pred->getLocationContext();
310  unsigned BlockId = L.getBlock()->getBlockID();
311  BlockCounter Counter = WList->getBlockCounter();
312  Counter = BCounterFactory.IncrementCount(Counter, LC->getStackFrame(),
313                                           BlockId);
314  setBlockCounter(Counter);
315
316  // Process the entrance of the block.
317  if (std::optional<CFGElement> E = L.getFirstElement()) {
318    NodeBuilderContext Ctx(*this, L.getBlock(), Pred);
319    ExprEng.processCFGElement(*E, Pred, 0, &Ctx);
320  } else
321    HandleBlockExit(L.getBlock(), Pred);
322}
323
324void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
325  if (const Stmt *Term = B->getTerminatorStmt()) {
326    switch (Term->getStmtClass()) {
327      default:
328        llvm_unreachable("Analysis for this terminator not implemented.");
329
330      case Stmt::CXXBindTemporaryExprClass:
331        HandleCleanupTemporaryBranch(
332            cast<CXXBindTemporaryExpr>(Term), B, Pred);
333        return;
334
335      // Model static initializers.
336      case Stmt::DeclStmtClass:
337        HandleStaticInit(cast<DeclStmt>(Term), B, Pred);
338        return;
339
340      case Stmt::BinaryOperatorClass: // '&&' and '||'
341        HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
342        return;
343
344      case Stmt::BinaryConditionalOperatorClass:
345      case Stmt::ConditionalOperatorClass:
346        HandleBranch(cast<AbstractConditionalOperator>(Term)->getCond(),
347                     Term, B, Pred);
348        return;
349
350        // FIXME: Use constant-folding in CFG construction to simplify this
351        // case.
352
353      case Stmt::ChooseExprClass:
354        HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
355        return;
356
357      case Stmt::CXXTryStmtClass:
358        // Generate a node for each of the successors.
359        // Our logic for EH analysis can certainly be improved.
360        for (CFGBlock::const_succ_iterator it = B->succ_begin(),
361             et = B->succ_end(); it != et; ++it) {
362          if (const CFGBlock *succ = *it) {
363            generateNode(BlockEdge(B, succ, Pred->getLocationContext()),
364                         Pred->State, Pred);
365          }
366        }
367        return;
368
369      case Stmt::DoStmtClass:
370        HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
371        return;
372
373      case Stmt::CXXForRangeStmtClass:
374        HandleBranch(cast<CXXForRangeStmt>(Term)->getCond(), Term, B, Pred);
375        return;
376
377      case Stmt::ForStmtClass:
378        HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
379        return;
380
381      case Stmt::SEHLeaveStmtClass:
382      case Stmt::ContinueStmtClass:
383      case Stmt::BreakStmtClass:
384      case Stmt::GotoStmtClass:
385        break;
386
387      case Stmt::IfStmtClass:
388        HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
389        return;
390
391      case Stmt::IndirectGotoStmtClass: {
392        // Only 1 successor: the indirect goto dispatch block.
393        assert(B->succ_size() == 1);
394
395        IndirectGotoNodeBuilder
396           builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
397                   *(B->succ_begin()), this);
398
399        ExprEng.processIndirectGoto(builder);
400        return;
401      }
402
403      case Stmt::ObjCForCollectionStmtClass:
404        // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
405        //
406        //  (1) inside a basic block, which represents the binding of the
407        //      'element' variable to a value.
408        //  (2) in a terminator, which represents the branch.
409        //
410        // For (1), ExprEngine will bind a value (i.e., 0 or 1) indicating
411        // whether or not collection contains any more elements.  We cannot
412        // just test to see if the element is nil because a container can
413        // contain nil elements.
414        HandleBranch(Term, Term, B, Pred);
415        return;
416
417      case Stmt::SwitchStmtClass: {
418        SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
419                                    this);
420
421        ExprEng.processSwitch(builder);
422        return;
423      }
424
425      case Stmt::WhileStmtClass:
426        HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
427        return;
428
429      case Stmt::GCCAsmStmtClass:
430        assert(cast<GCCAsmStmt>(Term)->isAsmGoto() && "Encountered GCCAsmStmt without labels");
431        // TODO: Handle jumping to labels
432        return;
433    }
434  }
435
436  if (B->getTerminator().isVirtualBaseBranch()) {
437    HandleVirtualBaseBranch(B, Pred);
438    return;
439  }
440
441  assert(B->succ_size() == 1 &&
442         "Blocks with no terminator should have at most 1 successor.");
443
444  generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
445               Pred->State, Pred);
446}
447
448void CoreEngine::HandleCallEnter(const CallEnter &CE, ExplodedNode *Pred) {
449  NodeBuilderContext BuilderCtx(*this, CE.getEntry(), Pred);
450  ExprEng.processCallEnter(BuilderCtx, CE, Pred);
451}
452
453void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
454                                const CFGBlock * B, ExplodedNode *Pred) {
455  assert(B->succ_size() == 2);
456  NodeBuilderContext Ctx(*this, B, Pred);
457  ExplodedNodeSet Dst;
458  ExprEng.processBranch(Cond, Ctx, Pred, Dst, *(B->succ_begin()),
459                       *(B->succ_begin() + 1));
460  // Enqueue the new frontier onto the worklist.
461  enqueue(Dst);
462}
463
464void CoreEngine::HandleCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,
465                                              const CFGBlock *B,
466                                              ExplodedNode *Pred) {
467  assert(B->succ_size() == 2);
468  NodeBuilderContext Ctx(*this, B, Pred);
469  ExplodedNodeSet Dst;
470  ExprEng.processCleanupTemporaryBranch(BTE, Ctx, Pred, Dst, *(B->succ_begin()),
471                                       *(B->succ_begin() + 1));
472  // Enqueue the new frontier onto the worklist.
473  enqueue(Dst);
474}
475
476void CoreEngine::HandleStaticInit(const DeclStmt *DS, const CFGBlock *B,
477                                  ExplodedNode *Pred) {
478  assert(B->succ_size() == 2);
479  NodeBuilderContext Ctx(*this, B, Pred);
480  ExplodedNodeSet Dst;
481  ExprEng.processStaticInitializer(DS, 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::HandlePostStmt(const CFGBlock *B, unsigned StmtIdx,
488                                ExplodedNode *Pred) {
489  assert(B);
490  assert(!B->empty());
491
492  if (StmtIdx == B->size())
493    HandleBlockExit(B, Pred);
494  else {
495    NodeBuilderContext Ctx(*this, B, Pred);
496    ExprEng.processCFGElement((*B)[StmtIdx], Pred, StmtIdx, &Ctx);
497  }
498}
499
500void CoreEngine::HandleVirtualBaseBranch(const CFGBlock *B,
501                                         ExplodedNode *Pred) {
502  const LocationContext *LCtx = Pred->getLocationContext();
503  if (const auto *CallerCtor = dyn_cast_or_null<CXXConstructExpr>(
504          LCtx->getStackFrame()->getCallSite())) {
505    switch (CallerCtor->getConstructionKind()) {
506    case CXXConstructionKind::NonVirtualBase:
507    case CXXConstructionKind::VirtualBase: {
508      BlockEdge Loc(B, *B->succ_begin(), LCtx);
509      HandleBlockEdge(Loc, Pred);
510      return;
511    }
512    default:
513      break;
514    }
515  }
516
517  // We either don't see a parent stack frame because we're in the top frame,
518  // or the parent stack frame doesn't initialize our virtual bases.
519  BlockEdge Loc(B, *(B->succ_begin() + 1), LCtx);
520  HandleBlockEdge(Loc, Pred);
521}
522
523/// generateNode - Utility method to generate nodes, hook up successors,
524///  and add nodes to the worklist.
525void CoreEngine::generateNode(const ProgramPoint &Loc,
526                              ProgramStateRef State,
527                              ExplodedNode *Pred) {
528  bool IsNew;
529  ExplodedNode *Node = G.getNode(Loc, State, false, &IsNew);
530
531  if (Pred)
532    Node->addPredecessor(Pred, G); // Link 'Node' with its predecessor.
533  else {
534    assert(IsNew);
535    G.addRoot(Node); // 'Node' has no predecessor.  Make it a root.
536  }
537
538  // Only add 'Node' to the worklist if it was freshly generated.
539  if (IsNew) WList->enqueue(Node);
540}
541
542void CoreEngine::enqueueStmtNode(ExplodedNode *N,
543                                 const CFGBlock *Block, unsigned Idx) {
544  assert(Block);
545  assert(!N->isSink());
546
547  // Check if this node entered a callee.
548  if (N->getLocation().getAs<CallEnter>()) {
549    // Still use the index of the CallExpr. It's needed to create the callee
550    // StackFrameContext.
551    WList->enqueue(N, Block, Idx);
552    return;
553  }
554
555  // Do not create extra nodes. Move to the next CFG element.
556  if (N->getLocation().getAs<PostInitializer>() ||
557      N->getLocation().getAs<PostImplicitCall>()||
558      N->getLocation().getAs<LoopExit>()) {
559    WList->enqueue(N, Block, Idx+1);
560    return;
561  }
562
563  if (N->getLocation().getAs<EpsilonPoint>()) {
564    WList->enqueue(N, Block, Idx);
565    return;
566  }
567
568  if ((*Block)[Idx].getKind() == CFGElement::NewAllocator) {
569    WList->enqueue(N, Block, Idx+1);
570    return;
571  }
572
573  // At this point, we know we're processing a normal statement.
574  CFGStmt CS = (*Block)[Idx].castAs<CFGStmt>();
575  PostStmt Loc(CS.getStmt(), N->getLocationContext());
576
577  if (Loc == N->getLocation().withTag(nullptr)) {
578    // Note: 'N' should be a fresh node because otherwise it shouldn't be
579    // a member of Deferred.
580    WList->enqueue(N, Block, Idx+1);
581    return;
582  }
583
584  bool IsNew;
585  ExplodedNode *Succ = G.getNode(Loc, N->getState(), false, &IsNew);
586  Succ->addPredecessor(N, G);
587
588  if (IsNew)
589    WList->enqueue(Succ, Block, Idx+1);
590}
591
592ExplodedNode *CoreEngine::generateCallExitBeginNode(ExplodedNode *N,
593                                                    const ReturnStmt *RS) {
594  // Create a CallExitBegin node and enqueue it.
595  const auto *LocCtx = cast<StackFrameContext>(N->getLocationContext());
596
597  // Use the callee location context.
598  CallExitBegin Loc(LocCtx, RS);
599
600  bool isNew;
601  ExplodedNode *Node = G.getNode(Loc, N->getState(), false, &isNew);
602  Node->addPredecessor(N, G);
603  return isNew ? Node : nullptr;
604}
605
606void CoreEngine::enqueue(ExplodedNodeSet &Set) {
607  for (const auto I : Set)
608    WList->enqueue(I);
609}
610
611void CoreEngine::enqueue(ExplodedNodeSet &Set,
612                         const CFGBlock *Block, unsigned Idx) {
613  for (const auto I : Set)
614    enqueueStmtNode(I, Block, Idx);
615}
616
617void CoreEngine::enqueueEndOfFunction(ExplodedNodeSet &Set, const ReturnStmt *RS) {
618  for (auto *I : Set) {
619    // If we are in an inlined call, generate CallExitBegin node.
620    if (I->getLocationContext()->getParent()) {
621      I = generateCallExitBeginNode(I, RS);
622      if (I)
623        WList->enqueue(I);
624    } else {
625      // TODO: We should run remove dead bindings here.
626      G.addEndOfPath(I);
627      NumPathsExplored++;
628    }
629  }
630}
631
632void NodeBuilder::anchor() {}
633
634ExplodedNode* NodeBuilder::generateNodeImpl(const ProgramPoint &Loc,
635                                            ProgramStateRef State,
636                                            ExplodedNode *FromN,
637                                            bool MarkAsSink) {
638  HasGeneratedNodes = true;
639  bool IsNew;
640  ExplodedNode *N = C.Eng.G.getNode(Loc, State, MarkAsSink, &IsNew);
641  N->addPredecessor(FromN, C.Eng.G);
642  Frontier.erase(FromN);
643
644  if (!IsNew)
645    return nullptr;
646
647  if (!MarkAsSink)
648    Frontier.Add(N);
649
650  return N;
651}
652
653void NodeBuilderWithSinks::anchor() {}
654
655StmtNodeBuilder::~StmtNodeBuilder() {
656  if (EnclosingBldr)
657    for (const auto I : Frontier)
658      EnclosingBldr->addNodes(I);
659}
660
661void BranchNodeBuilder::anchor() {}
662
663ExplodedNode *BranchNodeBuilder::generateNode(ProgramStateRef State,
664                                              bool branch,
665                                              ExplodedNode *NodePred) {
666  // If the branch has been marked infeasible we should not generate a node.
667  if (!isFeasible(branch))
668    return nullptr;
669
670  ProgramPoint Loc = BlockEdge(C.Block, branch ? DstT:DstF,
671                               NodePred->getLocationContext());
672  ExplodedNode *Succ = generateNodeImpl(Loc, State, NodePred);
673  return Succ;
674}
675
676ExplodedNode*
677IndirectGotoNodeBuilder::generateNode(const iterator &I,
678                                      ProgramStateRef St,
679                                      bool IsSink) {
680  bool IsNew;
681  ExplodedNode *Succ =
682      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
683                    St, IsSink, &IsNew);
684  Succ->addPredecessor(Pred, Eng.G);
685
686  if (!IsNew)
687    return nullptr;
688
689  if (!IsSink)
690    Eng.WList->enqueue(Succ);
691
692  return Succ;
693}
694
695ExplodedNode*
696SwitchNodeBuilder::generateCaseStmtNode(const iterator &I,
697                                        ProgramStateRef St) {
698  bool IsNew;
699  ExplodedNode *Succ =
700      Eng.G.getNode(BlockEdge(Src, I.getBlock(), Pred->getLocationContext()),
701                    St, false, &IsNew);
702  Succ->addPredecessor(Pred, Eng.G);
703  if (!IsNew)
704    return nullptr;
705
706  Eng.WList->enqueue(Succ);
707  return Succ;
708}
709
710ExplodedNode*
711SwitchNodeBuilder::generateDefaultCaseNode(ProgramStateRef St,
712                                           bool IsSink) {
713  // Get the block for the default case.
714  assert(Src->succ_rbegin() != Src->succ_rend());
715  CFGBlock *DefaultBlock = *Src->succ_rbegin();
716
717  // Basic correctness check for default blocks that are unreachable and not
718  // caught by earlier stages.
719  if (!DefaultBlock)
720    return nullptr;
721
722  bool IsNew;
723  ExplodedNode *Succ =
724      Eng.G.getNode(BlockEdge(Src, DefaultBlock, Pred->getLocationContext()),
725                    St, IsSink, &IsNew);
726  Succ->addPredecessor(Pred, Eng.G);
727
728  if (!IsNew)
729    return nullptr;
730
731  if (!IsSink)
732    Eng.WList->enqueue(Succ);
733
734  return Succ;
735}
736