lib/StaticAnalyzer/CoreEngine.cpp

   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/PathSensitive/AnalysisManager.h"
  16 #include "clang/StaticAnalyzer/PathSensitive/CoreEngine.h"
  17 #include "clang/StaticAnalyzer/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"
  22 #include <vector>
  23 #include <queue>
  24
  25 using llvm::cast;
  26 using llvm::isa;
  27 using namespace clang;
  28 using namespace ento;
  29
  30 // This should be removed in the future.
  31 namespace clang {
  32 namespace ento {
  33 TransferFuncs* MakeCFRefCountTF(ASTContext& Ctx, bool GCEnabled,
  34                                   const LangOptions& lopts);
  35 }
  36 }
  37
  38 //===----------------------------------------------------------------------===//
  39 // Worklist classes for exploration of reachable states.
  40 //===----------------------------------------------------------------------===//
  41
  42 WorkList::Visitor::~Visitor() {}
  43
  44 namespace {
  45 class DFS : public WorkList {
  46   llvm::SmallVector<WorkListUnit,20> Stack;
  47 public:
  48   virtual bool hasWork() const {
  49     return !Stack.empty();
  50   }
  51
  52   virtual void enqueue(const WorkListUnit& U) {
  53     Stack.push_back(U);
  54   }
  55
  56   virtual WorkListUnit dequeue() {
  57     assert (!Stack.empty());
  58     const WorkListUnit& U = Stack.back();
  59     Stack.pop_back(); // This technically "invalidates" U, but we are fine.
  60     return U;
  61   }
  62
  63   virtual bool visitItemsInWorkList(Visitor &V) {
  64     for (llvm::SmallVectorImpl<WorkListUnit>::iterator
  65          I = Stack.begin(), E = Stack.end(); I != E; ++I) {
  66       if (V.visit(*I))
  67         return true;
  68     }
  69     return false;
  70   }
  71 };
  72
  73 class BFS : public WorkList {
  74   std::deque<WorkListUnit> Queue;
  75 public:
  76   virtual bool hasWork() const {
  77     return !Queue.empty();
  78   }
  79
  80   virtual void enqueue(const WorkListUnit& U) {
  81     Queue.push_front(U);
  82   }
  83
  84   virtual WorkListUnit dequeue() {
  85     WorkListUnit U = Queue.front();
  86     Queue.pop_front();
  87     return U;
  88   }
  89
  90   virtual bool visitItemsInWorkList(Visitor &V) {
  91     for (std::deque<WorkListUnit>::iterator
  92          I = Queue.begin(), E = Queue.end(); I != E; ++I) {
  93       if (V.visit(*I))
  94         return true;
  95     }
  96     return false;
  97   }
  98 };
  99
 100 } // end anonymous namespace
 101
 102 // Place the dstor for WorkList here because it contains virtual member
 103 // functions, and we the code for the dstor generated in one compilation unit.
 104 WorkList::~WorkList() {}
 105
 106 WorkList *WorkList::makeDFS() { return new DFS(); }
 107 WorkList *WorkList::makeBFS() { return new BFS(); }
 108
 109 namespace {
 110   class BFSBlockDFSContents : public WorkList {
 111     std::deque<WorkListUnit> Queue;
 112     llvm::SmallVector<WorkListUnit,20> Stack;
 113   public:
 114     virtual bool hasWork() const {
 115       return !Queue.empty() || !Stack.empty();
 116     }
 117
 118     virtual void enqueue(const WorkListUnit& U) {
 119       if (isa<BlockEntrance>(U.getNode()->getLocation()))
 120         Queue.push_front(U);
 121       else
 122         Stack.push_back(U);
 123     }
 124
 125     virtual WorkListUnit dequeue() {
 126       // Process all basic blocks to completion.
 127       if (!Stack.empty()) {
 128         const WorkListUnit& U = Stack.back();
 129         Stack.pop_back(); // This technically "invalidates" U, but we are fine.
 130         return U;
 131       }
 132
 133       assert(!Queue.empty());
 134       // Don't use const reference.  The subsequent pop_back() might make it
 135       // unsafe.
 136       WorkListUnit U = Queue.front();
 137       Queue.pop_front();
 138       return U;
 139     }
 140     virtual bool visitItemsInWorkList(Visitor &V) {
 141       for (llvm::SmallVectorImpl<WorkListUnit>::iterator
 142            I = Stack.begin(), E = Stack.end(); I != E; ++I) {
 143         if (V.visit(*I))
 144           return true;
 145       }
 146       for (std::deque<WorkListUnit>::iterator
 147            I = Queue.begin(), E = Queue.end(); I != E; ++I) {
 148         if (V.visit(*I))
 149           return true;
 150       }
 151       return false;
 152     }
 153
 154   };
 155 } // end anonymous namespace
 156
 157 WorkList* WorkList::makeBFSBlockDFSContents() {
 158   return new BFSBlockDFSContents();
 159 }
 160
 161 //===----------------------------------------------------------------------===//
 162 // Core analysis engine.
 163 //===----------------------------------------------------------------------===//
 164
 165 /// ExecuteWorkList - Run the worklist algorithm for a maximum number of steps.
 166 bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
 167                                    const GRState *InitState) {
 168
 169   if (G->num_roots() == 0) { // Initialize the analysis by constructing
 170     // the root if none exists.
 171
 172     const CFGBlock* Entry = &(L->getCFG()->getEntry());
 173
 174     assert (Entry->empty() &&
 175             "Entry block must be empty.");
 176
 177     assert (Entry->succ_size() == 1 &&
 178             "Entry block must have 1 successor.");
 179
 180     // Get the solitary successor.
 181     const CFGBlock* Succ = *(Entry->succ_begin());
 182
 183     // Construct an edge representing the
 184     // starting location in the function.
 185     BlockEdge StartLoc(Entry, Succ, L);
 186
 187     // Set the current block counter to being empty.
 188     WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
 189
 190     if (!InitState)
 191       // Generate the root.
 192       generateNode(StartLoc, SubEng.getInitialState(L), 0);
 193     else
 194       generateNode(StartLoc, InitState, 0);
 195   }
 196
 197   // Check if we have a steps limit
 198   bool UnlimitedSteps = Steps == 0;
 199
 200   while (WList->hasWork()) {
 201     if (!UnlimitedSteps) {
 202       if (Steps == 0)
 203         break;
 204       --Steps;
 205     }
 206
 207     const WorkListUnit& WU = WList->dequeue();
 208
 209     // Set the current block counter.
 210     WList->setBlockCounter(WU.getBlockCounter());
 211
 212     // Retrieve the node.
 213     ExplodedNode* Node = WU.getNode();
 214
 215     // Dispatch on the location type.
 216     switch (Node->getLocation().getKind()) {
 217       case ProgramPoint::BlockEdgeKind:
 218         HandleBlockEdge(cast<BlockEdge>(Node->getLocation()), Node);
 219         break;
 220
 221       case ProgramPoint::BlockEntranceKind:
 222         HandleBlockEntrance(cast<BlockEntrance>(Node->getLocation()), Node);
 223         break;
 224
 225       case ProgramPoint::BlockExitKind:
 226         assert (false && "BlockExit location never occur in forward analysis.");
 227         break;
 228
 229       case ProgramPoint::CallEnterKind:
 230         HandleCallEnter(cast<CallEnter>(Node->getLocation()), WU.getBlock(),
 231                         WU.getIndex(), Node);
 232         break;
 233
 234       case ProgramPoint::CallExitKind:
 235         HandleCallExit(cast<CallExit>(Node->getLocation()), Node);
 236         break;
 237
 238       default:
 239         assert(isa<PostStmt>(Node->getLocation()) ||
 240                isa<PostInitializer>(Node->getLocation()));
 241         HandlePostStmt(WU.getBlock(), WU.getIndex(), Node);
 242         break;
 243     }
 244   }
 245
 246   SubEng.processEndWorklist(hasWorkRemaining());
 247   return WList->hasWork();
 248 }
 249
 250 void CoreEngine::ExecuteWorkListWithInitialState(const LocationContext *L,
 251                                                    unsigned Steps,
 252                                                    const GRState *InitState,
 253                                                    ExplodedNodeSet &Dst) {
 254   ExecuteWorkList(L, Steps, InitState);
 255   for (llvm::SmallVectorImpl<ExplodedNode*>::iterator I = G->EndNodes.begin(),
 256                                            E = G->EndNodes.end(); I != E; ++I) {
 257     Dst.Add(*I);
 258   }
 259 }
 260
 261 void CoreEngine::HandleCallEnter(const CallEnter &L, const CFGBlock *Block,
 262                                    unsigned Index, ExplodedNode *Pred) {
 263   CallEnterNodeBuilder Builder(*this, Pred, L.getCallExpr(),
 264                                  L.getCalleeContext(), Block, Index);
 265   SubEng.processCallEnter(Builder);
 266 }
 267
 268 void CoreEngine::HandleCallExit(const CallExit &L, ExplodedNode *Pred) {
 269   CallExitNodeBuilder Builder(*this, Pred);
 270   SubEng.processCallExit(Builder);
 271 }
 272
 273 void CoreEngine::HandleBlockEdge(const BlockEdge& L, ExplodedNode* Pred) {
 274
 275   const CFGBlock* Blk = L.getDst();
 276
 277   // Check if we are entering the EXIT block.
 278   if (Blk == &(L.getLocationContext()->getCFG()->getExit())) {
 279
 280     assert (L.getLocationContext()->getCFG()->getExit().size() == 0
 281             && "EXIT block cannot contain Stmts.");
 282
 283     // Process the final state transition.
 284     EndOfFunctionNodeBuilder Builder(Blk, Pred, this);
 285     SubEng.processEndOfFunction(Builder);
 286
 287     // This path is done. Don't enqueue any more nodes.
 288     return;
 289   }
 290
 291   // Call into the subengine to process entering the CFGBlock.
 292   ExplodedNodeSet dstNodes;
 293   BlockEntrance BE(Blk, Pred->getLocationContext());
 294   GenericNodeBuilder<BlockEntrance> nodeBuilder(*this, Pred, BE);
 295   SubEng.processCFGBlockEntrance(dstNodes, nodeBuilder);
 296
 297   if (dstNodes.empty()) {
 298     if (!nodeBuilder.hasGeneratedNode) {
 299       // Auto-generate a node and enqueue it to the worklist.
 300       generateNode(BE, Pred->State, Pred);
 301     }
 302   }
 303   else {
 304     for (ExplodedNodeSet::iterator I = dstNodes.begin(), E = dstNodes.end();
 305          I != E; ++I) {
 306       WList->enqueue(*I);
 307     }
 308   }
 309
 310   for (llvm::SmallVectorImpl<ExplodedNode*>::const_iterator
 311        I = nodeBuilder.sinks().begin(), E = nodeBuilder.sinks().end();
 312        I != E; ++I) {
 313     blocksAborted.push_back(std::make_pair(L, *I));
 314   }
 315 }
 316
 317 void CoreEngine::HandleBlockEntrance(const BlockEntrance& L,
 318                                        ExplodedNode* Pred) {
 319
 320   // Increment the block counter.
 321   BlockCounter Counter = WList->getBlockCounter();
 322   Counter = BCounterFactory.IncrementCount(Counter,
 323                              Pred->getLocationContext()->getCurrentStackFrame(),
 324                                            L.getBlock()->getBlockID());
 325   WList->setBlockCounter(Counter);
 326
 327   // Process the entrance of the block.
 328   if (CFGElement E = L.getFirstElement()) {
 329     StmtNodeBuilder Builder(L.getBlock(), 0, Pred, this,
 330                               SubEng.getStateManager());
 331     SubEng.processCFGElement(E, Builder);
 332   }
 333   else
 334     HandleBlockExit(L.getBlock(), Pred);
 335 }
 336
 337 void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode* Pred) {
 338
 339   if (const Stmt* Term = B->getTerminator()) {
 340     switch (Term->getStmtClass()) {
 341       default:
 342         assert(false && "Analysis for this terminator not implemented.");
 343         break;
 344
 345       case Stmt::BinaryOperatorClass: // '&&' and '||'
 346         HandleBranch(cast<BinaryOperator>(Term)->getLHS(), Term, B, Pred);
 347         return;
 348
 349       case Stmt::ConditionalOperatorClass:
 350         HandleBranch(cast<ConditionalOperator>(Term)->getCond(), Term, B, Pred);
 351         return;
 352
 353         // FIXME: Use constant-folding in CFG construction to simplify this
 354         // case.
 355
 356       case Stmt::ChooseExprClass:
 357         HandleBranch(cast<ChooseExpr>(Term)->getCond(), Term, B, Pred);
 358         return;
 359
 360       case Stmt::DoStmtClass:
 361         HandleBranch(cast<DoStmt>(Term)->getCond(), Term, B, Pred);
 362         return;
 363
 364       case Stmt::ForStmtClass:
 365         HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
 366         return;
 367
 368       case Stmt::ContinueStmtClass:
 369       case Stmt::BreakStmtClass:
 370       case Stmt::GotoStmtClass:
 371         break;
 372
 373       case Stmt::IfStmtClass:
 374         HandleBranch(cast<IfStmt>(Term)->getCond(), Term, B, Pred);
 375         return;
 376
 377       case Stmt::IndirectGotoStmtClass: {
 378         // Only 1 successor: the indirect goto dispatch block.
 379         assert (B->succ_size() == 1);
 380
 381         IndirectGotoNodeBuilder
 382            builder(Pred, B, cast<IndirectGotoStmt>(Term)->getTarget(),
 383                    *(B->succ_begin()), this);
 384
 385         SubEng.processIndirectGoto(builder);
 386         return;
 387       }
 388
 389       case Stmt::ObjCForCollectionStmtClass: {
 390         // In the case of ObjCForCollectionStmt, it appears twice in a CFG:
 391         //
 392         //  (1) inside a basic block, which represents the binding of the
 393         //      'element' variable to a value.
 394         //  (2) in a terminator, which represents the branch.
 395         //
 396         // For (1), subengines will bind a value (i.e., 0 or 1) indicating
 397         // whether or not collection contains any more elements.  We cannot
 398         // just test to see if the element is nil because a container can
 399         // contain nil elements.
 400         HandleBranch(Term, Term, B, Pred);
 401         return;
 402       }
 403
 404       case Stmt::SwitchStmtClass: {
 405         SwitchNodeBuilder builder(Pred, B, cast<SwitchStmt>(Term)->getCond(),
 406                                     this);
 407
 408         SubEng.processSwitch(builder);
 409         return;
 410       }
 411
 412       case Stmt::WhileStmtClass:
 413         HandleBranch(cast<WhileStmt>(Term)->getCond(), Term, B, Pred);
 414         return;
 415     }
 416   }
 417
 418   assert (B->succ_size() == 1 &&
 419           "Blocks with no terminator should have at most 1 successor.");
 420
 421   generateNode(BlockEdge(B, *(B->succ_begin()), Pred->getLocationContext()),
 422                Pred->State, Pred);
 423 }
 424
 425 void CoreEngine::HandleBranch(const Stmt* Cond, const Stmt* Term,
 426                                 const CFGBlock * B, ExplodedNode* Pred) {
 427   assert(B->succ_size() == 2);
 428   BranchNodeBuilder Builder(B, *(B->succ_begin()), *(B->succ_begin()+1),
 429                             Pred, this);
 430   SubEng.processBranch(Cond, Term, Builder);
 431 }
 432
 433 void CoreEngine::HandlePostStmt(const CFGBlock* B, unsigned StmtIdx,
 434                                   ExplodedNode* Pred) {
 435   assert (!B->empty());
 436
 437   if (StmtIdx == B->size())
 438     HandleBlockExit(B, Pred);
 439   else {
 440     StmtNodeBuilder Builder(B, StmtIdx, Pred, this,
 441                               SubEng.getStateManager());
 442     SubEng.processCFGElement((*B)[StmtIdx], Builder);
 443   }
 444 }
 445
 446 /// generateNode - Utility method to generate nodes, hook up successors,
 447 ///  and add nodes to the worklist.
 448 void CoreEngine::generateNode(const ProgramPoint& Loc,
 449                               const GRState* State, ExplodedNode* Pred) {
 450
 451   bool IsNew;
 452   ExplodedNode* Node = G->getNode(Loc, State, &IsNew);
 453
 454   if (Pred)
 455     Node->addPredecessor(Pred, *G);  // Link 'Node' with its predecessor.
 456   else {
 457     assert (IsNew);
 458     G->addRoot(Node);  // 'Node' has no predecessor.  Make it a root.
 459   }
 460
 461   // Only add 'Node' to the worklist if it was freshly generated.
 462   if (IsNew) WList->enqueue(Node);
 463 }
 464
 465 ExplodedNode *
 466 GenericNodeBuilderImpl::generateNodeImpl(const GRState *state,
 467                                          ExplodedNode *pred,
 468                                          ProgramPoint programPoint,
 469                                          bool asSink) {
 470
 471   hasGeneratedNode = true;
 472   bool isNew;
 473   ExplodedNode *node = engine.getGraph().getNode(programPoint, state, &isNew);
 474   if (pred)
 475     node->addPredecessor(pred, engine.getGraph());
 476   if (isNew) {
 477     if (asSink) {
 478       node->markAsSink();
 479       sinksGenerated.push_back(node);
 480     }
 481     return node;
 482   }
 483   return 0;
 484 }
 485
 486 StmtNodeBuilder::StmtNodeBuilder(const CFGBlock* b, unsigned idx,
 487                                      ExplodedNode* N, CoreEngine* e,
 488                                      GRStateManager &mgr)
 489   : Eng(*e), B(*b), Idx(idx), Pred(N), Mgr(mgr),
 490     PurgingDeadSymbols(false), BuildSinks(false), hasGeneratedNode(false),
 491     PointKind(ProgramPoint::PostStmtKind), Tag(0) {
 492   Deferred.insert(N);
 493   CleanedState = Pred->getState();
 494 }
 495
 496 StmtNodeBuilder::~StmtNodeBuilder() {
 497   for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
 498     if (!(*I)->isSink())
 499       GenerateAutoTransition(*I);
 500 }
 501
 502 void StmtNodeBuilder::GenerateAutoTransition(ExplodedNode* N) {
 503   assert (!N->isSink());
 504
 505   // Check if this node entered a callee.
 506   if (isa<CallEnter>(N->getLocation())) {
 507     // Still use the index of the CallExpr. It's needed to create the callee
 508     // StackFrameContext.
 509     Eng.WList->enqueue(N, &B, Idx);
 510     return;
 511   }
 512
 513   // Do not create extra nodes. Move to the next CFG element.
 514   if (isa<PostInitializer>(N->getLocation())) {
 515     Eng.WList->enqueue(N, &B, Idx+1);
 516     return;
 517   }
 518
 519   PostStmt Loc(getStmt(), N->getLocationContext());
 520
 521   if (Loc == N->getLocation()) {
 522     // Note: 'N' should be a fresh node because otherwise it shouldn't be
 523     // a member of Deferred.
 524     Eng.WList->enqueue(N, &B, Idx+1);
 525     return;
 526   }
 527
 528   bool IsNew;
 529   ExplodedNode* Succ = Eng.G->getNode(Loc, N->State, &IsNew);
 530   Succ->addPredecessor(N, *Eng.G);
 531
 532   if (IsNew)
 533     Eng.WList->enqueue(Succ, &B, Idx+1);
 534 }
 535
 536 ExplodedNode* StmtNodeBuilder::MakeNode(ExplodedNodeSet& Dst, const Stmt* S,
 537                                           ExplodedNode* Pred, const GRState* St,
 538                                           ProgramPoint::Kind K) {
 539
 540   ExplodedNode* N = generateNode(S, St, Pred, K);
 541
 542   if (N) {
 543     if (BuildSinks)
 544       N->markAsSink();
 545     else
 546       Dst.Add(N);
 547   }
 548
 549   return N;
 550 }
 551
 552 static ProgramPoint GetProgramPoint(const Stmt *S, ProgramPoint::Kind K,
 553                                     const LocationContext *LC, const void *tag){
 554   switch (K) {
 555     default:
 556       assert(false && "Unhandled ProgramPoint kind");
 557     case ProgramPoint::PreStmtKind:
 558       return PreStmt(S, LC, tag);
 559     case ProgramPoint::PostStmtKind:
 560       return PostStmt(S, LC, tag);
 561     case ProgramPoint::PreLoadKind:
 562       return PreLoad(S, LC, tag);
 563     case ProgramPoint::PostLoadKind:
 564       return PostLoad(S, LC, tag);
 565     case ProgramPoint::PreStoreKind:
 566       return PreStore(S, LC, tag);
 567     case ProgramPoint::PostStoreKind:
 568       return PostStore(S, LC, tag);
 569     case ProgramPoint::PostLValueKind:
 570       return PostLValue(S, LC, tag);
 571     case ProgramPoint::PostPurgeDeadSymbolsKind:
 572       return PostPurgeDeadSymbols(S, LC, tag);
 573   }
 574 }
 575
 576 ExplodedNode*
 577 StmtNodeBuilder::generateNodeInternal(const Stmt* S, const GRState* state,
 578                                         ExplodedNode* Pred,
 579                                         ProgramPoint::Kind K,
 580                                         const void *tag) {
 581
 582   const ProgramPoint &L = GetProgramPoint(S, K, Pred->getLocationContext(),tag);
 583   return generateNodeInternal(L, state, Pred);
 584 }
 585
 586 ExplodedNode*
 587 StmtNodeBuilder::generateNodeInternal(const ProgramPoint &Loc,
 588                                         const GRState* State,
 589                                         ExplodedNode* Pred) {
 590   bool IsNew;
 591   ExplodedNode* N = Eng.G->getNode(Loc, State, &IsNew);
 592   N->addPredecessor(Pred, *Eng.G);
 593   Deferred.erase(Pred);
 594
 595   if (IsNew) {
 596     Deferred.insert(N);
 597     return N;
 598   }
 599
 600   return NULL;
 601 }
 602
 603 ExplodedNode* BranchNodeBuilder::generateNode(const GRState* State,
 604                                                 bool branch) {
 605
 606   // If the branch has been marked infeasible we should not generate a node.
 607   if (!isFeasible(branch))
 608     return NULL;
 609
 610   bool IsNew;
 611
 612   ExplodedNode* Succ =
 613     Eng.G->getNode(BlockEdge(Src,branch ? DstT:DstF,Pred->getLocationContext()),
 614                    State, &IsNew);
 615
 616   Succ->addPredecessor(Pred, *Eng.G);
 617
 618   if (branch)
 619     GeneratedTrue = true;
 620   else
 621     GeneratedFalse = true;
 622
 623   if (IsNew) {
 624     Deferred.push_back(Succ);
 625     return Succ;
 626   }
 627
 628   return NULL;
 629 }
 630
 631 BranchNodeBuilder::~BranchNodeBuilder() {
 632   if (!GeneratedTrue) generateNode(Pred->State, true);
 633   if (!GeneratedFalse) generateNode(Pred->State, false);
 634
 635   for (DeferredTy::iterator I=Deferred.begin(), E=Deferred.end(); I!=E; ++I)
 636     if (!(*I)->isSink()) Eng.WList->enqueue(*I);
 637 }
 638
 639
 640 ExplodedNode*
 641 IndirectGotoNodeBuilder::generateNode(const iterator& I, const GRState* St,
 642                                         bool isSink) {
 643   bool IsNew;
 644
 645   ExplodedNode* Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
 646                                       Pred->getLocationContext()), St, &IsNew);
 647
 648   Succ->addPredecessor(Pred, *Eng.G);
 649
 650   if (IsNew) {
 651
 652     if (isSink)
 653       Succ->markAsSink();
 654     else
 655       Eng.WList->enqueue(Succ);
 656
 657     return Succ;
 658   }
 659
 660   return NULL;
 661 }
 662
 663
 664 ExplodedNode*
 665 SwitchNodeBuilder::generateCaseStmtNode(const iterator& I, const GRState* St){
 666
 667   bool IsNew;
 668
 669   ExplodedNode* Succ = Eng.G->getNode(BlockEdge(Src, I.getBlock(),
 670                                        Pred->getLocationContext()), St, &IsNew);
 671   Succ->addPredecessor(Pred, *Eng.G);
 672
 673   if (IsNew) {
 674     Eng.WList->enqueue(Succ);
 675     return Succ;
 676   }
 677
 678   return NULL;
 679 }
 680
 681
 682 ExplodedNode*
 683 SwitchNodeBuilder::generateDefaultCaseNode(const GRState* St, bool isSink) {
 684
 685   // Get the block for the default case.
 686   assert (Src->succ_rbegin() != Src->succ_rend());
 687   CFGBlock* DefaultBlock = *Src->succ_rbegin();
 688
 689   bool IsNew;
 690
 691   ExplodedNode* Succ = Eng.G->getNode(BlockEdge(Src, DefaultBlock,
 692                                        Pred->getLocationContext()), St, &IsNew);
 693   Succ->addPredecessor(Pred, *Eng.G);
 694
 695   if (IsNew) {
 696     if (isSink)
 697       Succ->markAsSink();
 698     else
 699       Eng.WList->enqueue(Succ);
 700
 701     return Succ;
 702   }
 703
 704   return NULL;
 705 }
 706
 707 EndOfFunctionNodeBuilder::~EndOfFunctionNodeBuilder() {
 708   // Auto-generate an EOP node if one has not been generated.
 709   if (!hasGeneratedNode) {
 710     // If we are in an inlined call, generate CallExit node.
 711     if (Pred->getLocationContext()->getParent())
 712       GenerateCallExitNode(Pred->State);
 713     else
 714       generateNode(Pred->State);
 715   }
 716 }
 717
 718 ExplodedNode*
 719 EndOfFunctionNodeBuilder::generateNode(const GRState* State, const void *tag,
 720                                    ExplodedNode* P) {
 721   hasGeneratedNode = true;
 722   bool IsNew;
 723
 724   ExplodedNode* Node = Eng.G->getNode(BlockEntrance(&B,
 725                                Pred->getLocationContext(), tag), State, &IsNew);
 726
 727   Node->addPredecessor(P ? P : Pred, *Eng.G);
 728
 729   if (IsNew) {
 730     Eng.G->addEndOfPath(Node);
 731     return Node;
 732   }
 733
 734   return NULL;
 735 }
 736
 737 void EndOfFunctionNodeBuilder::GenerateCallExitNode(const GRState *state) {
 738   hasGeneratedNode = true;
 739   // Create a CallExit node and enqueue it.
 740   const StackFrameContext *LocCtx
 741                          = cast<StackFrameContext>(Pred->getLocationContext());
 742   const Stmt *CE = LocCtx->getCallSite();
 743
 744   // Use the the callee location context.
 745   CallExit Loc(CE, LocCtx);
 746
 747   bool isNew;
 748   ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
 749   Node->addPredecessor(Pred, *Eng.G);
 750
 751   if (isNew)
 752     Eng.WList->enqueue(Node);
 753 }
 754
 755
 756 void CallEnterNodeBuilder::generateNode(const GRState *state) {
 757   // Check if the callee is in the same translation unit.
 758   if (CalleeCtx->getTranslationUnit() !=
 759       Pred->getLocationContext()->getTranslationUnit()) {
 760     // Create a new engine. We must be careful that the new engine should not
 761     // reference data structures owned by the old engine.
 762
 763     AnalysisManager &OldMgr = Eng.SubEng.getAnalysisManager();
 764
 765     // Get the callee's translation unit.
 766     idx::TranslationUnit *TU = CalleeCtx->getTranslationUnit();
 767
 768     // Create a new AnalysisManager with components of the callee's
 769     // TranslationUnit.
 770     // The Diagnostic is actually shared when we create ASTUnits from AST files.
 771     AnalysisManager AMgr(TU->getASTContext(), TU->getDiagnostic(),
 772                          OldMgr.getLangOptions(),
 773                          OldMgr.getPathDiagnosticClient(),
 774                          OldMgr.getStoreManagerCreator(),
 775                          OldMgr.getConstraintManagerCreator(),
 776                          OldMgr.getIndexer(),
 777                          OldMgr.getMaxNodes(), OldMgr.getMaxVisit(),
 778                          OldMgr.shouldVisualizeGraphviz(),
 779                          OldMgr.shouldVisualizeUbigraph(),
 780                          OldMgr.shouldPurgeDead(),
 781                          OldMgr.shouldEagerlyAssume(),
 782                          OldMgr.shouldTrimGraph(),
 783                          OldMgr.shouldInlineCall(),
 784                      OldMgr.getAnalysisContextManager().getUseUnoptimizedCFG(),
 785                      OldMgr.getAnalysisContextManager().getAddImplicitDtors(),
 786                      OldMgr.getAnalysisContextManager().getAddInitializers());
 787     llvm::OwningPtr<TransferFuncs> TF(MakeCFRefCountTF(AMgr.getASTContext(),
 788                                                          /* GCEnabled */ false,
 789                                                         AMgr.getLangOptions()));
 790     // Create the new engine.
 791     ExprEngine NewEng(AMgr, TF.take());
 792
 793     // Create the new LocationContext.
 794     AnalysisContext *NewAnaCtx = AMgr.getAnalysisContext(CalleeCtx->getDecl(),
 795                                                CalleeCtx->getTranslationUnit());
 796     const StackFrameContext *OldLocCtx = CalleeCtx;
 797     const StackFrameContext *NewLocCtx = AMgr.getStackFrame(NewAnaCtx,
 798                                                OldLocCtx->getParent(),
 799                                                OldLocCtx->getCallSite(),
 800                                                OldLocCtx->getCallSiteBlock(),
 801                                                OldLocCtx->getIndex());
 802
 803     // Now create an initial state for the new engine.
 804     const GRState *NewState = NewEng.getStateManager().MarshalState(state,
 805                                                                     NewLocCtx);
 806     ExplodedNodeSet ReturnNodes;
 807     NewEng.ExecuteWorkListWithInitialState(NewLocCtx, AMgr.getMaxNodes(),
 808                                            NewState, ReturnNodes);
 809     return;
 810   }
 811
 812   // Get the callee entry block.
 813   const CFGBlock *Entry = &(CalleeCtx->getCFG()->getEntry());
 814   assert(Entry->empty());
 815   assert(Entry->succ_size() == 1);
 816
 817   // Get the solitary successor.
 818   const CFGBlock *SuccB = *(Entry->succ_begin());
 819
 820   // Construct an edge representing the starting location in the callee.
 821   BlockEdge Loc(Entry, SuccB, CalleeCtx);
 822
 823   bool isNew;
 824   ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
 825   Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
 826
 827   if (isNew)
 828     Eng.WList->enqueue(Node);
 829 }
 830
 831 void CallExitNodeBuilder::generateNode(const GRState *state) {
 832   // Get the callee's location context.
 833   const StackFrameContext *LocCtx
 834                          = cast<StackFrameContext>(Pred->getLocationContext());
 835   // When exiting an implicit automatic obj dtor call, the callsite is the Stmt
 836   // that triggers the dtor.
 837   PostStmt Loc(LocCtx->getCallSite(), LocCtx->getParent());
 838   bool isNew;
 839   ExplodedNode *Node = Eng.G->getNode(Loc, state, &isNew);
 840   Node->addPredecessor(const_cast<ExplodedNode*>(Pred), *Eng.G);
 841   if (isNew)
 842     Eng.WList->enqueue(Node, LocCtx->getCallSiteBlock(),
 843                        LocCtx->getIndex() + 1);
 844 }