1 //=-- ExprEngineCallAndReturn.cpp - Support for call/return -----*- C++ -*-===// 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 ExprEngine's support for calls and returns. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "clang/AST/Decl.h" 14 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 15 #include "PrettyStackTraceLocationContext.h" 16 #include "clang/AST/CXXInheritance.h" 17 #include "clang/AST/DeclCXX.h" 18 #include "clang/Analysis/Analyses/LiveVariables.h" 19 #include "clang/Analysis/ConstructionContext.h" 20 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 22 #include "llvm/ADT/SmallSet.h" 23 #include "llvm/ADT/Statistic.h" 24 #include "llvm/Support/SaveAndRestore.h" 25 26 using namespace clang; 27 using namespace ento; 28 29 #define DEBUG_TYPE "ExprEngine" 30 31 STATISTIC(NumOfDynamicDispatchPathSplits, 32 "The # of times we split the path due to imprecise dynamic dispatch info"); 33 34 STATISTIC(NumInlinedCalls, 35 "The # of times we inlined a call"); 36 37 STATISTIC(NumReachedInlineCountMax, 38 "The # of times we reached inline count maximum"); 39 40 void ExprEngine::processCallEnter(NodeBuilderContext& BC, CallEnter CE, 41 ExplodedNode *Pred) { 42 // Get the entry block in the CFG of the callee. 43 const StackFrameContext *calleeCtx = CE.getCalleeContext(); 44 PrettyStackTraceLocationContext CrashInfo(calleeCtx); 45 const CFGBlock *Entry = CE.getEntry(); 46 47 // Validate the CFG. 48 assert(Entry->empty()); 49 assert(Entry->succ_size() == 1); 50 51 // Get the solitary successor. 52 const CFGBlock *Succ = *(Entry->succ_begin()); 53 54 // Construct an edge representing the starting location in the callee. 55 BlockEdge Loc(Entry, Succ, calleeCtx); 56 57 ProgramStateRef state = Pred->getState(); 58 59 // Construct a new node, notify checkers that analysis of the function has 60 // begun, and add the resultant nodes to the worklist. 61 bool isNew; 62 ExplodedNode *Node = G.getNode(Loc, state, false, &isNew); 63 Node->addPredecessor(Pred, G); 64 if (isNew) { 65 ExplodedNodeSet DstBegin; 66 processBeginOfFunction(BC, Node, DstBegin, Loc); 67 Engine.enqueue(DstBegin); 68 } 69 } 70 71 // Find the last statement on the path to the exploded node and the 72 // corresponding Block. 73 static std::pair<const Stmt*, 74 const CFGBlock*> getLastStmt(const ExplodedNode *Node) { 75 const Stmt *S = nullptr; 76 const CFGBlock *Blk = nullptr; 77 const StackFrameContext *SF = Node->getStackFrame(); 78 79 // Back up through the ExplodedGraph until we reach a statement node in this 80 // stack frame. 81 while (Node) { 82 const ProgramPoint &PP = Node->getLocation(); 83 84 if (PP.getStackFrame() == SF) { 85 if (Optional<StmtPoint> SP = PP.getAs<StmtPoint>()) { 86 S = SP->getStmt(); 87 break; 88 } else if (Optional<CallExitEnd> CEE = PP.getAs<CallExitEnd>()) { 89 S = CEE->getCalleeContext()->getCallSite(); 90 if (S) 91 break; 92 93 // If there is no statement, this is an implicitly-generated call. 94 // We'll walk backwards over it and then continue the loop to find 95 // an actual statement. 96 Optional<CallEnter> CE; 97 do { 98 Node = Node->getFirstPred(); 99 CE = Node->getLocationAs<CallEnter>(); 100 } while (!CE || CE->getCalleeContext() != CEE->getCalleeContext()); 101 102 // Continue searching the graph. 103 } else if (Optional<BlockEdge> BE = PP.getAs<BlockEdge>()) { 104 Blk = BE->getSrc(); 105 } 106 } else if (Optional<CallEnter> CE = PP.getAs<CallEnter>()) { 107 // If we reached the CallEnter for this function, it has no statements. 108 if (CE->getCalleeContext() == SF) 109 break; 110 } 111 112 if (Node->pred_empty()) 113 return std::make_pair(nullptr, nullptr); 114 115 Node = *Node->pred_begin(); 116 } 117 118 return std::make_pair(S, Blk); 119 } 120 121 /// Adjusts a return value when the called function's return type does not 122 /// match the caller's expression type. This can happen when a dynamic call 123 /// is devirtualized, and the overriding method has a covariant (more specific) 124 /// return type than the parent's method. For C++ objects, this means we need 125 /// to add base casts. 126 static SVal adjustReturnValue(SVal V, QualType ExpectedTy, QualType ActualTy, 127 StoreManager &StoreMgr) { 128 // For now, the only adjustments we handle apply only to locations. 129 if (!V.getAs<Loc>()) 130 return V; 131 132 // If the types already match, don't do any unnecessary work. 133 ExpectedTy = ExpectedTy.getCanonicalType(); 134 ActualTy = ActualTy.getCanonicalType(); 135 if (ExpectedTy == ActualTy) 136 return V; 137 138 // No adjustment is needed between Objective-C pointer types. 139 if (ExpectedTy->isObjCObjectPointerType() && 140 ActualTy->isObjCObjectPointerType()) 141 return V; 142 143 // C++ object pointers may need "derived-to-base" casts. 144 const CXXRecordDecl *ExpectedClass = ExpectedTy->getPointeeCXXRecordDecl(); 145 const CXXRecordDecl *ActualClass = ActualTy->getPointeeCXXRecordDecl(); 146 if (ExpectedClass && ActualClass) { 147 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 148 /*DetectVirtual=*/false); 149 if (ActualClass->isDerivedFrom(ExpectedClass, Paths) && 150 !Paths.isAmbiguous(ActualTy->getCanonicalTypeUnqualified())) { 151 return StoreMgr.evalDerivedToBase(V, Paths.front()); 152 } 153 } 154 155 // Unfortunately, Objective-C does not enforce that overridden methods have 156 // covariant return types, so we can't assert that that never happens. 157 // Be safe and return UnknownVal(). 158 return UnknownVal(); 159 } 160 161 void ExprEngine::removeDeadOnEndOfFunction(NodeBuilderContext& BC, 162 ExplodedNode *Pred, 163 ExplodedNodeSet &Dst) { 164 // Find the last statement in the function and the corresponding basic block. 165 const Stmt *LastSt = nullptr; 166 const CFGBlock *Blk = nullptr; 167 std::tie(LastSt, Blk) = getLastStmt(Pred); 168 if (!Blk || !LastSt) { 169 Dst.Add(Pred); 170 return; 171 } 172 173 // Here, we destroy the current location context. We use the current 174 // function's entire body as a diagnostic statement, with which the program 175 // point will be associated. However, we only want to use LastStmt as a 176 // reference for what to clean up if it's a ReturnStmt; otherwise, everything 177 // is dead. 178 SaveAndRestore<const NodeBuilderContext *> NodeContextRAII(currBldrCtx, &BC); 179 const LocationContext *LCtx = Pred->getLocationContext(); 180 removeDead(Pred, Dst, dyn_cast<ReturnStmt>(LastSt), LCtx, 181 LCtx->getAnalysisDeclContext()->getBody(), 182 ProgramPoint::PostStmtPurgeDeadSymbolsKind); 183 } 184 185 static bool wasDifferentDeclUsedForInlining(CallEventRef<> Call, 186 const StackFrameContext *calleeCtx) { 187 const Decl *RuntimeCallee = calleeCtx->getDecl(); 188 const Decl *StaticDecl = Call->getDecl(); 189 assert(RuntimeCallee); 190 if (!StaticDecl) 191 return true; 192 return RuntimeCallee->getCanonicalDecl() != StaticDecl->getCanonicalDecl(); 193 } 194 195 /// The call exit is simulated with a sequence of nodes, which occur between 196 /// CallExitBegin and CallExitEnd. The following operations occur between the 197 /// two program points: 198 /// 1. CallExitBegin (triggers the start of call exit sequence) 199 /// 2. Bind the return value 200 /// 3. Run Remove dead bindings to clean up the dead symbols from the callee. 201 /// 4. CallExitEnd (switch to the caller context) 202 /// 5. PostStmt<CallExpr> 203 void ExprEngine::processCallExit(ExplodedNode *CEBNode) { 204 // Step 1 CEBNode was generated before the call. 205 PrettyStackTraceLocationContext CrashInfo(CEBNode->getLocationContext()); 206 const StackFrameContext *calleeCtx = CEBNode->getStackFrame(); 207 208 // The parent context might not be a stack frame, so make sure we 209 // look up the first enclosing stack frame. 210 const StackFrameContext *callerCtx = 211 calleeCtx->getParent()->getStackFrame(); 212 213 const Stmt *CE = calleeCtx->getCallSite(); 214 ProgramStateRef state = CEBNode->getState(); 215 // Find the last statement in the function and the corresponding basic block. 216 const Stmt *LastSt = nullptr; 217 const CFGBlock *Blk = nullptr; 218 std::tie(LastSt, Blk) = getLastStmt(CEBNode); 219 220 // Generate a CallEvent /before/ cleaning the state, so that we can get the 221 // correct value for 'this' (if necessary). 222 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 223 CallEventRef<> Call = CEMgr.getCaller(calleeCtx, state); 224 225 // Step 2: generate node with bound return value: CEBNode -> BindedRetNode. 226 227 // If the callee returns an expression, bind its value to CallExpr. 228 if (CE) { 229 if (const ReturnStmt *RS = dyn_cast_or_null<ReturnStmt>(LastSt)) { 230 const LocationContext *LCtx = CEBNode->getLocationContext(); 231 SVal V = state->getSVal(RS, LCtx); 232 233 // Ensure that the return type matches the type of the returned Expr. 234 if (wasDifferentDeclUsedForInlining(Call, calleeCtx)) { 235 QualType ReturnedTy = 236 CallEvent::getDeclaredResultType(calleeCtx->getDecl()); 237 if (!ReturnedTy.isNull()) { 238 if (const Expr *Ex = dyn_cast<Expr>(CE)) { 239 V = adjustReturnValue(V, Ex->getType(), ReturnedTy, 240 getStoreManager()); 241 } 242 } 243 } 244 245 state = state->BindExpr(CE, callerCtx, V); 246 } 247 248 // Bind the constructed object value to CXXConstructExpr. 249 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(CE)) { 250 loc::MemRegionVal This = 251 svalBuilder.getCXXThis(CCE->getConstructor()->getParent(), calleeCtx); 252 SVal ThisV = state->getSVal(This); 253 ThisV = state->getSVal(ThisV.castAs<Loc>()); 254 state = state->BindExpr(CCE, callerCtx, ThisV); 255 } 256 257 if (const auto *CNE = dyn_cast<CXXNewExpr>(CE)) { 258 // We are currently evaluating a CXXNewAllocator CFGElement. It takes a 259 // while to reach the actual CXXNewExpr element from here, so keep the 260 // region for later use. 261 // Additionally cast the return value of the inlined operator new 262 // (which is of type 'void *') to the correct object type. 263 SVal AllocV = state->getSVal(CNE, callerCtx); 264 AllocV = svalBuilder.evalCast( 265 AllocV, CNE->getType(), 266 getContext().getPointerType(getContext().VoidTy)); 267 268 state = addObjectUnderConstruction(state, CNE, calleeCtx->getParent(), 269 AllocV); 270 } 271 } 272 273 // Step 3: BindedRetNode -> CleanedNodes 274 // If we can find a statement and a block in the inlined function, run remove 275 // dead bindings before returning from the call. This is important to ensure 276 // that we report the issues such as leaks in the stack contexts in which 277 // they occurred. 278 ExplodedNodeSet CleanedNodes; 279 if (LastSt && Blk && AMgr.options.AnalysisPurgeOpt != PurgeNone) { 280 static SimpleProgramPointTag retValBind("ExprEngine", "Bind Return Value"); 281 PostStmt Loc(LastSt, calleeCtx, &retValBind); 282 bool isNew; 283 ExplodedNode *BindedRetNode = G.getNode(Loc, state, false, &isNew); 284 BindedRetNode->addPredecessor(CEBNode, G); 285 if (!isNew) 286 return; 287 288 NodeBuilderContext Ctx(getCoreEngine(), Blk, BindedRetNode); 289 currBldrCtx = &Ctx; 290 // Here, we call the Symbol Reaper with 0 statement and callee location 291 // context, telling it to clean up everything in the callee's context 292 // (and its children). We use the callee's function body as a diagnostic 293 // statement, with which the program point will be associated. 294 removeDead(BindedRetNode, CleanedNodes, nullptr, calleeCtx, 295 calleeCtx->getAnalysisDeclContext()->getBody(), 296 ProgramPoint::PostStmtPurgeDeadSymbolsKind); 297 currBldrCtx = nullptr; 298 } else { 299 CleanedNodes.Add(CEBNode); 300 } 301 302 for (ExplodedNodeSet::iterator I = CleanedNodes.begin(), 303 E = CleanedNodes.end(); I != E; ++I) { 304 305 // Step 4: Generate the CallExit and leave the callee's context. 306 // CleanedNodes -> CEENode 307 CallExitEnd Loc(calleeCtx, callerCtx); 308 bool isNew; 309 ProgramStateRef CEEState = (*I == CEBNode) ? state : (*I)->getState(); 310 311 ExplodedNode *CEENode = G.getNode(Loc, CEEState, false, &isNew); 312 CEENode->addPredecessor(*I, G); 313 if (!isNew) 314 return; 315 316 // Step 5: Perform the post-condition check of the CallExpr and enqueue the 317 // result onto the work list. 318 // CEENode -> Dst -> WorkList 319 NodeBuilderContext Ctx(Engine, calleeCtx->getCallSiteBlock(), CEENode); 320 SaveAndRestore<const NodeBuilderContext*> NBCSave(currBldrCtx, 321 &Ctx); 322 SaveAndRestore<unsigned> CBISave(currStmtIdx, calleeCtx->getIndex()); 323 324 CallEventRef<> UpdatedCall = Call.cloneWithState(CEEState); 325 326 ExplodedNodeSet DstPostCall; 327 if (const CXXNewExpr *CNE = dyn_cast_or_null<CXXNewExpr>(CE)) { 328 ExplodedNodeSet DstPostPostCallCallback; 329 getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback, 330 CEENode, *UpdatedCall, *this, 331 /*wasInlined=*/true); 332 for (auto I : DstPostPostCallCallback) { 333 getCheckerManager().runCheckersForNewAllocator( 334 CNE, 335 *getObjectUnderConstruction(I->getState(), CNE, 336 calleeCtx->getParent()), 337 DstPostCall, I, *this, 338 /*wasInlined=*/true); 339 } 340 } else { 341 getCheckerManager().runCheckersForPostCall(DstPostCall, CEENode, 342 *UpdatedCall, *this, 343 /*wasInlined=*/true); 344 } 345 ExplodedNodeSet Dst; 346 if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(Call)) { 347 getCheckerManager().runCheckersForPostObjCMessage(Dst, DstPostCall, *Msg, 348 *this, 349 /*wasInlined=*/true); 350 } else if (CE && 351 !(isa<CXXNewExpr>(CE) && // Called when visiting CXXNewExpr. 352 AMgr.getAnalyzerOptions().MayInlineCXXAllocator)) { 353 getCheckerManager().runCheckersForPostStmt(Dst, DstPostCall, CE, 354 *this, /*wasInlined=*/true); 355 } else { 356 Dst.insert(DstPostCall); 357 } 358 359 // Enqueue the next element in the block. 360 for (ExplodedNodeSet::iterator PSI = Dst.begin(), PSE = Dst.end(); 361 PSI != PSE; ++PSI) { 362 Engine.getWorkList()->enqueue(*PSI, calleeCtx->getCallSiteBlock(), 363 calleeCtx->getIndex()+1); 364 } 365 } 366 } 367 368 bool ExprEngine::isSmall(AnalysisDeclContext *ADC) const { 369 // When there are no branches in the function, it means that there's no 370 // exponential complexity introduced by inlining such function. 371 // Such functions also don't trigger various fundamental problems 372 // with our inlining mechanism, such as the problem of 373 // inlined defensive checks. Hence isLinear(). 374 const CFG *Cfg = ADC->getCFG(); 375 return Cfg->isLinear() || Cfg->size() <= AMgr.options.AlwaysInlineSize; 376 } 377 378 bool ExprEngine::isLarge(AnalysisDeclContext *ADC) const { 379 const CFG *Cfg = ADC->getCFG(); 380 return Cfg->size() >= AMgr.options.MinCFGSizeTreatFunctionsAsLarge; 381 } 382 383 bool ExprEngine::isHuge(AnalysisDeclContext *ADC) const { 384 const CFG *Cfg = ADC->getCFG(); 385 return Cfg->getNumBlockIDs() > AMgr.options.MaxInlinableSize; 386 } 387 388 void ExprEngine::examineStackFrames(const Decl *D, const LocationContext *LCtx, 389 bool &IsRecursive, unsigned &StackDepth) { 390 IsRecursive = false; 391 StackDepth = 0; 392 393 while (LCtx) { 394 if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LCtx)) { 395 const Decl *DI = SFC->getDecl(); 396 397 // Mark recursive (and mutually recursive) functions and always count 398 // them when measuring the stack depth. 399 if (DI == D) { 400 IsRecursive = true; 401 ++StackDepth; 402 LCtx = LCtx->getParent(); 403 continue; 404 } 405 406 // Do not count the small functions when determining the stack depth. 407 AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(DI); 408 if (!isSmall(CalleeADC)) 409 ++StackDepth; 410 } 411 LCtx = LCtx->getParent(); 412 } 413 } 414 415 // The GDM component containing the dynamic dispatch bifurcation info. When 416 // the exact type of the receiver is not known, we want to explore both paths - 417 // one on which we do inline it and the other one on which we don't. This is 418 // done to ensure we do not drop coverage. 419 // This is the map from the receiver region to a bool, specifying either we 420 // consider this region's information precise or not along the given path. 421 namespace { 422 enum DynamicDispatchMode { 423 DynamicDispatchModeInlined = 1, 424 DynamicDispatchModeConservative 425 }; 426 } // end anonymous namespace 427 428 REGISTER_MAP_WITH_PROGRAMSTATE(DynamicDispatchBifurcationMap, 429 const MemRegion *, unsigned) 430 431 bool ExprEngine::inlineCall(const CallEvent &Call, const Decl *D, 432 NodeBuilder &Bldr, ExplodedNode *Pred, 433 ProgramStateRef State) { 434 assert(D); 435 436 const LocationContext *CurLC = Pred->getLocationContext(); 437 const StackFrameContext *CallerSFC = CurLC->getStackFrame(); 438 const LocationContext *ParentOfCallee = CallerSFC; 439 if (Call.getKind() == CE_Block && 440 !cast<BlockCall>(Call).isConversionFromLambda()) { 441 const BlockDataRegion *BR = cast<BlockCall>(Call).getBlockRegion(); 442 assert(BR && "If we have the block definition we should have its region"); 443 AnalysisDeclContext *BlockCtx = AMgr.getAnalysisDeclContext(D); 444 ParentOfCallee = BlockCtx->getBlockInvocationContext(CallerSFC, 445 cast<BlockDecl>(D), 446 BR); 447 } 448 449 // This may be NULL, but that's fine. 450 const Expr *CallE = Call.getOriginExpr(); 451 452 // Construct a new stack frame for the callee. 453 AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(D); 454 const StackFrameContext *CalleeSFC = 455 CalleeADC->getStackFrame(ParentOfCallee, CallE, currBldrCtx->getBlock(), 456 currBldrCtx->blockCount(), currStmtIdx); 457 458 CallEnter Loc(CallE, CalleeSFC, CurLC); 459 460 // Construct a new state which contains the mapping from actual to 461 // formal arguments. 462 State = State->enterStackFrame(Call, CalleeSFC); 463 464 bool isNew; 465 if (ExplodedNode *N = G.getNode(Loc, State, false, &isNew)) { 466 N->addPredecessor(Pred, G); 467 if (isNew) 468 Engine.getWorkList()->enqueue(N); 469 } 470 471 // If we decided to inline the call, the successor has been manually 472 // added onto the work list so remove it from the node builder. 473 Bldr.takeNodes(Pred); 474 475 NumInlinedCalls++; 476 Engine.FunctionSummaries->bumpNumTimesInlined(D); 477 478 // Mark the decl as visited. 479 if (VisitedCallees) 480 VisitedCallees->insert(D); 481 482 return true; 483 } 484 485 static ProgramStateRef getInlineFailedState(ProgramStateRef State, 486 const Stmt *CallE) { 487 const void *ReplayState = State->get<ReplayWithoutInlining>(); 488 if (!ReplayState) 489 return nullptr; 490 491 assert(ReplayState == CallE && "Backtracked to the wrong call."); 492 (void)CallE; 493 494 return State->remove<ReplayWithoutInlining>(); 495 } 496 497 void ExprEngine::VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred, 498 ExplodedNodeSet &dst) { 499 // Perform the previsit of the CallExpr. 500 ExplodedNodeSet dstPreVisit; 501 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, CE, *this); 502 503 // Get the call in its initial state. We use this as a template to perform 504 // all the checks. 505 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 506 CallEventRef<> CallTemplate 507 = CEMgr.getSimpleCall(CE, Pred->getState(), Pred->getLocationContext()); 508 509 // Evaluate the function call. We try each of the checkers 510 // to see if the can evaluate the function call. 511 ExplodedNodeSet dstCallEvaluated; 512 for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end(); 513 I != E; ++I) { 514 evalCall(dstCallEvaluated, *I, *CallTemplate); 515 } 516 517 // Finally, perform the post-condition check of the CallExpr and store 518 // the created nodes in 'Dst'. 519 // Note that if the call was inlined, dstCallEvaluated will be empty. 520 // The post-CallExpr check will occur in processCallExit. 521 getCheckerManager().runCheckersForPostStmt(dst, dstCallEvaluated, CE, 522 *this); 523 } 524 525 ProgramStateRef ExprEngine::finishArgumentConstruction(ProgramStateRef State, 526 const CallEvent &Call) { 527 const Expr *E = Call.getOriginExpr(); 528 // FIXME: Constructors to placement arguments of operator new 529 // are not supported yet. 530 if (!E || isa<CXXNewExpr>(E)) 531 return State; 532 533 const LocationContext *LC = Call.getLocationContext(); 534 for (unsigned CallI = 0, CallN = Call.getNumArgs(); CallI != CallN; ++CallI) { 535 unsigned I = Call.getASTArgumentIndex(CallI); 536 if (Optional<SVal> V = 537 getObjectUnderConstruction(State, {E, I}, LC)) { 538 SVal VV = *V; 539 (void)VV; 540 assert(cast<VarRegion>(VV.castAs<loc::MemRegionVal>().getRegion()) 541 ->getStackFrame()->getParent() 542 ->getStackFrame() == LC->getStackFrame()); 543 State = finishObjectConstruction(State, {E, I}, LC); 544 } 545 } 546 547 return State; 548 } 549 550 void ExprEngine::finishArgumentConstruction(ExplodedNodeSet &Dst, 551 ExplodedNode *Pred, 552 const CallEvent &Call) { 553 ProgramStateRef State = Pred->getState(); 554 ProgramStateRef CleanedState = finishArgumentConstruction(State, Call); 555 if (CleanedState == State) { 556 Dst.insert(Pred); 557 return; 558 } 559 560 const Expr *E = Call.getOriginExpr(); 561 const LocationContext *LC = Call.getLocationContext(); 562 NodeBuilder B(Pred, Dst, *currBldrCtx); 563 static SimpleProgramPointTag Tag("ExprEngine", 564 "Finish argument construction"); 565 PreStmt PP(E, LC, &Tag); 566 B.generateNode(PP, CleanedState, Pred); 567 } 568 569 void ExprEngine::evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred, 570 const CallEvent &Call) { 571 // WARNING: At this time, the state attached to 'Call' may be older than the 572 // state in 'Pred'. This is a minor optimization since CheckerManager will 573 // use an updated CallEvent instance when calling checkers, but if 'Call' is 574 // ever used directly in this function all callers should be updated to pass 575 // the most recent state. (It is probably not worth doing the work here since 576 // for some callers this will not be necessary.) 577 578 // Run any pre-call checks using the generic call interface. 579 ExplodedNodeSet dstPreVisit; 580 getCheckerManager().runCheckersForPreCall(dstPreVisit, Pred, 581 Call, *this); 582 583 // Actually evaluate the function call. We try each of the checkers 584 // to see if the can evaluate the function call, and get a callback at 585 // defaultEvalCall if all of them fail. 586 ExplodedNodeSet dstCallEvaluated; 587 getCheckerManager().runCheckersForEvalCall(dstCallEvaluated, dstPreVisit, 588 Call, *this); 589 590 // If there were other constructors called for object-type arguments 591 // of this call, clean them up. 592 ExplodedNodeSet dstArgumentCleanup; 593 for (auto I : dstCallEvaluated) 594 finishArgumentConstruction(dstArgumentCleanup, I, Call); 595 596 ExplodedNodeSet dstPostCall; 597 getCheckerManager().runCheckersForPostCall(dstPostCall, dstArgumentCleanup, 598 Call, *this); 599 600 // Escaping symbols conjured during invalidating the regions above. 601 // Note that, for inlined calls the nodes were put back into the worklist, 602 // so we can assume that every node belongs to a conservative call at this 603 // point. 604 605 // Run pointerEscape callback with the newly conjured symbols. 606 SmallVector<std::pair<SVal, SVal>, 8> Escaped; 607 for (auto I : dstPostCall) { 608 NodeBuilder B(I, Dst, *currBldrCtx); 609 ProgramStateRef State = I->getState(); 610 Escaped.clear(); 611 { 612 unsigned Arg = -1; 613 for (const ParmVarDecl *PVD : Call.parameters()) { 614 ++Arg; 615 QualType ParamTy = PVD->getType(); 616 if (ParamTy.isNull() || 617 (!ParamTy->isPointerType() && !ParamTy->isReferenceType())) 618 continue; 619 QualType Pointee = ParamTy->getPointeeType(); 620 if (Pointee.isConstQualified() || Pointee->isVoidType()) 621 continue; 622 if (const MemRegion *MR = Call.getArgSVal(Arg).getAsRegion()) 623 Escaped.emplace_back(loc::MemRegionVal(MR), State->getSVal(MR, Pointee)); 624 } 625 } 626 627 State = processPointerEscapedOnBind(State, Escaped, I->getLocationContext(), 628 PSK_EscapeOutParameters, &Call); 629 630 if (State == I->getState()) 631 Dst.insert(I); 632 else 633 B.generateNode(I->getLocation(), State, I); 634 } 635 } 636 637 ProgramStateRef ExprEngine::bindReturnValue(const CallEvent &Call, 638 const LocationContext *LCtx, 639 ProgramStateRef State) { 640 const Expr *E = Call.getOriginExpr(); 641 if (!E) 642 return State; 643 644 // Some method families have known return values. 645 if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(&Call)) { 646 switch (Msg->getMethodFamily()) { 647 default: 648 break; 649 case OMF_autorelease: 650 case OMF_retain: 651 case OMF_self: { 652 // These methods return their receivers. 653 return State->BindExpr(E, LCtx, Msg->getReceiverSVal()); 654 } 655 } 656 } else if (const CXXConstructorCall *C = dyn_cast<CXXConstructorCall>(&Call)){ 657 SVal ThisV = C->getCXXThisVal(); 658 ThisV = State->getSVal(ThisV.castAs<Loc>()); 659 return State->BindExpr(E, LCtx, ThisV); 660 } 661 662 SVal R; 663 QualType ResultTy = Call.getResultType(); 664 unsigned Count = currBldrCtx->blockCount(); 665 if (auto RTC = getCurrentCFGElement().getAs<CFGCXXRecordTypedCall>()) { 666 // Conjure a temporary if the function returns an object by value. 667 SVal Target; 668 assert(RTC->getStmt() == Call.getOriginExpr()); 669 EvalCallOptions CallOpts; // FIXME: We won't really need those. 670 std::tie(State, Target) = 671 prepareForObjectConstruction(Call.getOriginExpr(), State, LCtx, 672 RTC->getConstructionContext(), CallOpts); 673 const MemRegion *TargetR = Target.getAsRegion(); 674 assert(TargetR); 675 // Invalidate the region so that it didn't look uninitialized. If this is 676 // a field or element constructor, we do not want to invalidate 677 // the whole structure. Pointer escape is meaningless because 678 // the structure is a product of conservative evaluation 679 // and therefore contains nothing interesting at this point. 680 RegionAndSymbolInvalidationTraits ITraits; 681 ITraits.setTrait(TargetR, 682 RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 683 State = State->invalidateRegions(TargetR, E, Count, LCtx, 684 /* CausesPointerEscape=*/false, nullptr, 685 &Call, &ITraits); 686 687 R = State->getSVal(Target.castAs<Loc>(), E->getType()); 688 } else { 689 // Conjure a symbol if the return value is unknown. 690 691 // See if we need to conjure a heap pointer instead of 692 // a regular unknown pointer. 693 bool IsHeapPointer = false; 694 if (const auto *CNE = dyn_cast<CXXNewExpr>(E)) 695 if (CNE->getOperatorNew()->isReplaceableGlobalAllocationFunction()) { 696 // FIXME: Delegate this to evalCall in MallocChecker? 697 IsHeapPointer = true; 698 } 699 700 R = IsHeapPointer ? svalBuilder.getConjuredHeapSymbolVal(E, LCtx, Count) 701 : svalBuilder.conjureSymbolVal(nullptr, E, LCtx, ResultTy, 702 Count); 703 } 704 return State->BindExpr(E, LCtx, R); 705 } 706 707 // Conservatively evaluate call by invalidating regions and binding 708 // a conjured return value. 709 void ExprEngine::conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr, 710 ExplodedNode *Pred, ProgramStateRef State) { 711 State = Call.invalidateRegions(currBldrCtx->blockCount(), State); 712 State = bindReturnValue(Call, Pred->getLocationContext(), State); 713 714 // And make the result node. 715 Bldr.generateNode(Call.getProgramPoint(), State, Pred); 716 } 717 718 ExprEngine::CallInlinePolicy 719 ExprEngine::mayInlineCallKind(const CallEvent &Call, const ExplodedNode *Pred, 720 AnalyzerOptions &Opts, 721 const ExprEngine::EvalCallOptions &CallOpts) { 722 const LocationContext *CurLC = Pred->getLocationContext(); 723 const StackFrameContext *CallerSFC = CurLC->getStackFrame(); 724 switch (Call.getKind()) { 725 case CE_Function: 726 case CE_Block: 727 break; 728 case CE_CXXMember: 729 case CE_CXXMemberOperator: 730 if (!Opts.mayInlineCXXMemberFunction(CIMK_MemberFunctions)) 731 return CIP_DisallowedAlways; 732 break; 733 case CE_CXXConstructor: { 734 if (!Opts.mayInlineCXXMemberFunction(CIMK_Constructors)) 735 return CIP_DisallowedAlways; 736 737 const CXXConstructorCall &Ctor = cast<CXXConstructorCall>(Call); 738 739 const CXXConstructExpr *CtorExpr = Ctor.getOriginExpr(); 740 741 auto CCE = getCurrentCFGElement().getAs<CFGConstructor>(); 742 const ConstructionContext *CC = CCE ? CCE->getConstructionContext() 743 : nullptr; 744 745 if (CC && isa<NewAllocatedObjectConstructionContext>(CC) && 746 !Opts.MayInlineCXXAllocator) 747 return CIP_DisallowedOnce; 748 749 // FIXME: We don't handle constructors or destructors for arrays properly. 750 // Even once we do, we still need to be careful about implicitly-generated 751 // initializers for array fields in default move/copy constructors. 752 // We still allow construction into ElementRegion targets when they don't 753 // represent array elements. 754 if (CallOpts.IsArrayCtorOrDtor) 755 return CIP_DisallowedOnce; 756 757 // Inlining constructors requires including initializers in the CFG. 758 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); 759 assert(ADC->getCFGBuildOptions().AddInitializers && "No CFG initializers"); 760 (void)ADC; 761 762 // If the destructor is trivial, it's always safe to inline the constructor. 763 if (Ctor.getDecl()->getParent()->hasTrivialDestructor()) 764 break; 765 766 // For other types, only inline constructors if destructor inlining is 767 // also enabled. 768 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) 769 return CIP_DisallowedAlways; 770 771 if (CtorExpr->getConstructionKind() == CXXConstructExpr::CK_Complete) { 772 // If we don't handle temporary destructors, we shouldn't inline 773 // their constructors. 774 if (CallOpts.IsTemporaryCtorOrDtor && 775 !Opts.ShouldIncludeTemporaryDtorsInCFG) 776 return CIP_DisallowedOnce; 777 778 // If we did not find the correct this-region, it would be pointless 779 // to inline the constructor. Instead we will simply invalidate 780 // the fake temporary target. 781 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) 782 return CIP_DisallowedOnce; 783 784 // If the temporary is lifetime-extended by binding it to a reference-type 785 // field within an aggregate, automatic destructors don't work properly. 786 if (CallOpts.IsTemporaryLifetimeExtendedViaAggregate) 787 return CIP_DisallowedOnce; 788 } 789 790 break; 791 } 792 case CE_CXXDestructor: { 793 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) 794 return CIP_DisallowedAlways; 795 796 // Inlining destructors requires building the CFG correctly. 797 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); 798 assert(ADC->getCFGBuildOptions().AddImplicitDtors && "No CFG destructors"); 799 (void)ADC; 800 801 // FIXME: We don't handle constructors or destructors for arrays properly. 802 if (CallOpts.IsArrayCtorOrDtor) 803 return CIP_DisallowedOnce; 804 805 // Allow disabling temporary destructor inlining with a separate option. 806 if (CallOpts.IsTemporaryCtorOrDtor && 807 !Opts.MayInlineCXXTemporaryDtors) 808 return CIP_DisallowedOnce; 809 810 // If we did not find the correct this-region, it would be pointless 811 // to inline the destructor. Instead we will simply invalidate 812 // the fake temporary target. 813 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) 814 return CIP_DisallowedOnce; 815 break; 816 } 817 case CE_CXXAllocator: 818 if (Opts.MayInlineCXXAllocator) 819 break; 820 // Do not inline allocators until we model deallocators. 821 // This is unfortunate, but basically necessary for smart pointers and such. 822 return CIP_DisallowedAlways; 823 case CE_ObjCMessage: 824 if (!Opts.MayInlineObjCMethod) 825 return CIP_DisallowedAlways; 826 if (!(Opts.getIPAMode() == IPAK_DynamicDispatch || 827 Opts.getIPAMode() == IPAK_DynamicDispatchBifurcate)) 828 return CIP_DisallowedAlways; 829 break; 830 } 831 832 return CIP_Allowed; 833 } 834 835 /// Returns true if the given C++ class contains a member with the given name. 836 static bool hasMember(const ASTContext &Ctx, const CXXRecordDecl *RD, 837 StringRef Name) { 838 const IdentifierInfo &II = Ctx.Idents.get(Name); 839 DeclarationName DeclName = Ctx.DeclarationNames.getIdentifier(&II); 840 if (!RD->lookup(DeclName).empty()) 841 return true; 842 843 CXXBasePaths Paths(false, false, false); 844 if (RD->lookupInBases( 845 [DeclName](const CXXBaseSpecifier *Specifier, CXXBasePath &Path) { 846 return CXXRecordDecl::FindOrdinaryMember(Specifier, Path, DeclName); 847 }, 848 Paths)) 849 return true; 850 851 return false; 852 } 853 854 /// Returns true if the given C++ class is a container or iterator. 855 /// 856 /// Our heuristic for this is whether it contains a method named 'begin()' or a 857 /// nested type named 'iterator' or 'iterator_category'. 858 static bool isContainerClass(const ASTContext &Ctx, const CXXRecordDecl *RD) { 859 return hasMember(Ctx, RD, "begin") || 860 hasMember(Ctx, RD, "iterator") || 861 hasMember(Ctx, RD, "iterator_category"); 862 } 863 864 /// Returns true if the given function refers to a method of a C++ container 865 /// or iterator. 866 /// 867 /// We generally do a poor job modeling most containers right now, and might 868 /// prefer not to inline their methods. 869 static bool isContainerMethod(const ASTContext &Ctx, 870 const FunctionDecl *FD) { 871 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) 872 return isContainerClass(Ctx, MD->getParent()); 873 return false; 874 } 875 876 /// Returns true if the given function is the destructor of a class named 877 /// "shared_ptr". 878 static bool isCXXSharedPtrDtor(const FunctionDecl *FD) { 879 const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(FD); 880 if (!Dtor) 881 return false; 882 883 const CXXRecordDecl *RD = Dtor->getParent(); 884 if (const IdentifierInfo *II = RD->getDeclName().getAsIdentifierInfo()) 885 if (II->isStr("shared_ptr")) 886 return true; 887 888 return false; 889 } 890 891 /// Returns true if the function in \p CalleeADC may be inlined in general. 892 /// 893 /// This checks static properties of the function, such as its signature and 894 /// CFG, to determine whether the analyzer should ever consider inlining it, 895 /// in any context. 896 bool ExprEngine::mayInlineDecl(AnalysisDeclContext *CalleeADC) const { 897 AnalyzerOptions &Opts = AMgr.getAnalyzerOptions(); 898 // FIXME: Do not inline variadic calls. 899 if (CallEvent::isVariadic(CalleeADC->getDecl())) 900 return false; 901 902 // Check certain C++-related inlining policies. 903 ASTContext &Ctx = CalleeADC->getASTContext(); 904 if (Ctx.getLangOpts().CPlusPlus) { 905 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeADC->getDecl())) { 906 // Conditionally control the inlining of template functions. 907 if (!Opts.MayInlineTemplateFunctions) 908 if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate) 909 return false; 910 911 // Conditionally control the inlining of C++ standard library functions. 912 if (!Opts.MayInlineCXXStandardLibrary) 913 if (Ctx.getSourceManager().isInSystemHeader(FD->getLocation())) 914 if (AnalysisDeclContext::isInStdNamespace(FD)) 915 return false; 916 917 // Conditionally control the inlining of methods on objects that look 918 // like C++ containers. 919 if (!Opts.MayInlineCXXContainerMethods) 920 if (!AMgr.isInCodeFile(FD->getLocation())) 921 if (isContainerMethod(Ctx, FD)) 922 return false; 923 924 // Conditionally control the inlining of the destructor of C++ shared_ptr. 925 // We don't currently do a good job modeling shared_ptr because we can't 926 // see the reference count, so treating as opaque is probably the best 927 // idea. 928 if (!Opts.MayInlineCXXSharedPtrDtor) 929 if (isCXXSharedPtrDtor(FD)) 930 return false; 931 } 932 } 933 934 // It is possible that the CFG cannot be constructed. 935 // Be safe, and check if the CalleeCFG is valid. 936 const CFG *CalleeCFG = CalleeADC->getCFG(); 937 if (!CalleeCFG) 938 return false; 939 940 // Do not inline large functions. 941 if (isHuge(CalleeADC)) 942 return false; 943 944 // It is possible that the live variables analysis cannot be 945 // run. If so, bail out. 946 if (!CalleeADC->getAnalysis<RelaxedLiveVariables>()) 947 return false; 948 949 return true; 950 } 951 952 bool ExprEngine::shouldInlineCall(const CallEvent &Call, const Decl *D, 953 const ExplodedNode *Pred, 954 const EvalCallOptions &CallOpts) { 955 if (!D) 956 return false; 957 958 AnalysisManager &AMgr = getAnalysisManager(); 959 AnalyzerOptions &Opts = AMgr.options; 960 AnalysisDeclContextManager &ADCMgr = AMgr.getAnalysisDeclContextManager(); 961 AnalysisDeclContext *CalleeADC = ADCMgr.getContext(D); 962 963 // The auto-synthesized bodies are essential to inline as they are 964 // usually small and commonly used. Note: we should do this check early on to 965 // ensure we always inline these calls. 966 if (CalleeADC->isBodyAutosynthesized()) 967 return true; 968 969 if (!AMgr.shouldInlineCall()) 970 return false; 971 972 // Check if this function has been marked as non-inlinable. 973 Optional<bool> MayInline = Engine.FunctionSummaries->mayInline(D); 974 if (MayInline.hasValue()) { 975 if (!MayInline.getValue()) 976 return false; 977 978 } else { 979 // We haven't actually checked the static properties of this function yet. 980 // Do that now, and record our decision in the function summaries. 981 if (mayInlineDecl(CalleeADC)) { 982 Engine.FunctionSummaries->markMayInline(D); 983 } else { 984 Engine.FunctionSummaries->markShouldNotInline(D); 985 return false; 986 } 987 } 988 989 // Check if we should inline a call based on its kind. 990 // FIXME: this checks both static and dynamic properties of the call, which 991 // means we're redoing a bit of work that could be cached in the function 992 // summary. 993 CallInlinePolicy CIP = mayInlineCallKind(Call, Pred, Opts, CallOpts); 994 if (CIP != CIP_Allowed) { 995 if (CIP == CIP_DisallowedAlways) { 996 assert(!MayInline.hasValue() || MayInline.getValue()); 997 Engine.FunctionSummaries->markShouldNotInline(D); 998 } 999 return false; 1000 } 1001 1002 // Do not inline if recursive or we've reached max stack frame count. 1003 bool IsRecursive = false; 1004 unsigned StackDepth = 0; 1005 examineStackFrames(D, Pred->getLocationContext(), IsRecursive, StackDepth); 1006 if ((StackDepth >= Opts.InlineMaxStackDepth) && 1007 (!isSmall(CalleeADC) || IsRecursive)) 1008 return false; 1009 1010 // Do not inline large functions too many times. 1011 if ((Engine.FunctionSummaries->getNumTimesInlined(D) > 1012 Opts.MaxTimesInlineLarge) && 1013 isLarge(CalleeADC)) { 1014 NumReachedInlineCountMax++; 1015 return false; 1016 } 1017 1018 if (HowToInline == Inline_Minimal && (!isSmall(CalleeADC) || IsRecursive)) 1019 return false; 1020 1021 return true; 1022 } 1023 1024 static bool isTrivialObjectAssignment(const CallEvent &Call) { 1025 const CXXInstanceCall *ICall = dyn_cast<CXXInstanceCall>(&Call); 1026 if (!ICall) 1027 return false; 1028 1029 const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(ICall->getDecl()); 1030 if (!MD) 1031 return false; 1032 if (!(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())) 1033 return false; 1034 1035 return MD->isTrivial(); 1036 } 1037 1038 void ExprEngine::defaultEvalCall(NodeBuilder &Bldr, ExplodedNode *Pred, 1039 const CallEvent &CallTemplate, 1040 const EvalCallOptions &CallOpts) { 1041 // Make sure we have the most recent state attached to the call. 1042 ProgramStateRef State = Pred->getState(); 1043 CallEventRef<> Call = CallTemplate.cloneWithState(State); 1044 1045 // Special-case trivial assignment operators. 1046 if (isTrivialObjectAssignment(*Call)) { 1047 performTrivialCopy(Bldr, Pred, *Call); 1048 return; 1049 } 1050 1051 // Try to inline the call. 1052 // The origin expression here is just used as a kind of checksum; 1053 // this should still be safe even for CallEvents that don't come from exprs. 1054 const Expr *E = Call->getOriginExpr(); 1055 1056 ProgramStateRef InlinedFailedState = getInlineFailedState(State, E); 1057 if (InlinedFailedState) { 1058 // If we already tried once and failed, make sure we don't retry later. 1059 State = InlinedFailedState; 1060 } else { 1061 RuntimeDefinition RD = Call->getRuntimeDefinition(); 1062 const Decl *D = RD.getDecl(); 1063 if (shouldInlineCall(*Call, D, Pred, CallOpts)) { 1064 if (RD.mayHaveOtherDefinitions()) { 1065 AnalyzerOptions &Options = getAnalysisManager().options; 1066 1067 // Explore with and without inlining the call. 1068 if (Options.getIPAMode() == IPAK_DynamicDispatchBifurcate) { 1069 BifurcateCall(RD.getDispatchRegion(), *Call, D, Bldr, Pred); 1070 return; 1071 } 1072 1073 // Don't inline if we're not in any dynamic dispatch mode. 1074 if (Options.getIPAMode() != IPAK_DynamicDispatch) { 1075 conservativeEvalCall(*Call, Bldr, Pred, State); 1076 return; 1077 } 1078 } 1079 1080 // We are not bifurcating and we do have a Decl, so just inline. 1081 if (inlineCall(*Call, D, Bldr, Pred, State)) 1082 return; 1083 } 1084 } 1085 1086 // If we can't inline it, handle the return value and invalidate the regions. 1087 conservativeEvalCall(*Call, Bldr, Pred, State); 1088 } 1089 1090 void ExprEngine::BifurcateCall(const MemRegion *BifurReg, 1091 const CallEvent &Call, const Decl *D, 1092 NodeBuilder &Bldr, ExplodedNode *Pred) { 1093 assert(BifurReg); 1094 BifurReg = BifurReg->StripCasts(); 1095 1096 // Check if we've performed the split already - note, we only want 1097 // to split the path once per memory region. 1098 ProgramStateRef State = Pred->getState(); 1099 const unsigned *BState = 1100 State->get<DynamicDispatchBifurcationMap>(BifurReg); 1101 if (BState) { 1102 // If we are on "inline path", keep inlining if possible. 1103 if (*BState == DynamicDispatchModeInlined) 1104 if (inlineCall(Call, D, Bldr, Pred, State)) 1105 return; 1106 // If inline failed, or we are on the path where we assume we 1107 // don't have enough info about the receiver to inline, conjure the 1108 // return value and invalidate the regions. 1109 conservativeEvalCall(Call, Bldr, Pred, State); 1110 return; 1111 } 1112 1113 // If we got here, this is the first time we process a message to this 1114 // region, so split the path. 1115 ProgramStateRef IState = 1116 State->set<DynamicDispatchBifurcationMap>(BifurReg, 1117 DynamicDispatchModeInlined); 1118 inlineCall(Call, D, Bldr, Pred, IState); 1119 1120 ProgramStateRef NoIState = 1121 State->set<DynamicDispatchBifurcationMap>(BifurReg, 1122 DynamicDispatchModeConservative); 1123 conservativeEvalCall(Call, Bldr, Pred, NoIState); 1124 1125 NumOfDynamicDispatchPathSplits++; 1126 } 1127 1128 void ExprEngine::VisitReturnStmt(const ReturnStmt *RS, ExplodedNode *Pred, 1129 ExplodedNodeSet &Dst) { 1130 ExplodedNodeSet dstPreVisit; 1131 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, RS, *this); 1132 1133 StmtNodeBuilder B(dstPreVisit, Dst, *currBldrCtx); 1134 1135 if (RS->getRetValue()) { 1136 for (ExplodedNodeSet::iterator it = dstPreVisit.begin(), 1137 ei = dstPreVisit.end(); it != ei; ++it) { 1138 B.generateNode(RS, *it, (*it)->getState()); 1139 } 1140 } 1141 } 1142