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 "PrettyStackTraceLocationContext.h" 14 #include "clang/AST/CXXInheritance.h" 15 #include "clang/AST/Decl.h" 16 #include "clang/AST/DeclCXX.h" 17 #include "clang/Analysis/Analyses/LiveVariables.h" 18 #include "clang/Analysis/ConstructionContext.h" 19 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 20 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 23 #include "llvm/ADT/SmallSet.h" 24 #include "llvm/ADT/Statistic.h" 25 #include "llvm/Support/Casting.h" 26 #include "llvm/Support/Compiler.h" 27 #include "llvm/Support/SaveAndRestore.h" 28 29 using namespace clang; 30 using namespace ento; 31 32 #define DEBUG_TYPE "ExprEngine" 33 34 STATISTIC(NumOfDynamicDispatchPathSplits, 35 "The # of times we split the path due to imprecise dynamic dispatch info"); 36 37 STATISTIC(NumInlinedCalls, 38 "The # of times we inlined a call"); 39 40 STATISTIC(NumReachedInlineCountMax, 41 "The # of times we reached inline count maximum"); 42 43 void ExprEngine::processCallEnter(NodeBuilderContext& BC, CallEnter CE, 44 ExplodedNode *Pred) { 45 // Get the entry block in the CFG of the callee. 46 const StackFrameContext *calleeCtx = CE.getCalleeContext(); 47 PrettyStackTraceLocationContext CrashInfo(calleeCtx); 48 const CFGBlock *Entry = CE.getEntry(); 49 50 // Validate the CFG. 51 assert(Entry->empty()); 52 assert(Entry->succ_size() == 1); 53 54 // Get the solitary successor. 55 const CFGBlock *Succ = *(Entry->succ_begin()); 56 57 // Construct an edge representing the starting location in the callee. 58 BlockEdge Loc(Entry, Succ, calleeCtx); 59 60 ProgramStateRef state = Pred->getState(); 61 62 // Construct a new node, notify checkers that analysis of the function has 63 // begun, and add the resultant nodes to the worklist. 64 bool isNew; 65 ExplodedNode *Node = G.getNode(Loc, state, false, &isNew); 66 Node->addPredecessor(Pred, G); 67 if (isNew) { 68 ExplodedNodeSet DstBegin; 69 processBeginOfFunction(BC, Node, DstBegin, Loc); 70 Engine.enqueue(DstBegin); 71 } 72 } 73 74 // Find the last statement on the path to the exploded node and the 75 // corresponding Block. 76 static std::pair<const Stmt*, 77 const CFGBlock*> getLastStmt(const ExplodedNode *Node) { 78 const Stmt *S = nullptr; 79 const CFGBlock *Blk = nullptr; 80 const StackFrameContext *SF = Node->getStackFrame(); 81 82 // Back up through the ExplodedGraph until we reach a statement node in this 83 // stack frame. 84 while (Node) { 85 const ProgramPoint &PP = Node->getLocation(); 86 87 if (PP.getStackFrame() == SF) { 88 if (Optional<StmtPoint> SP = PP.getAs<StmtPoint>()) { 89 S = SP->getStmt(); 90 break; 91 } else if (Optional<CallExitEnd> CEE = PP.getAs<CallExitEnd>()) { 92 S = CEE->getCalleeContext()->getCallSite(); 93 if (S) 94 break; 95 96 // If there is no statement, this is an implicitly-generated call. 97 // We'll walk backwards over it and then continue the loop to find 98 // an actual statement. 99 Optional<CallEnter> CE; 100 do { 101 Node = Node->getFirstPred(); 102 CE = Node->getLocationAs<CallEnter>(); 103 } while (!CE || CE->getCalleeContext() != CEE->getCalleeContext()); 104 105 // Continue searching the graph. 106 } else if (Optional<BlockEdge> BE = PP.getAs<BlockEdge>()) { 107 Blk = BE->getSrc(); 108 } 109 } else if (Optional<CallEnter> CE = PP.getAs<CallEnter>()) { 110 // If we reached the CallEnter for this function, it has no statements. 111 if (CE->getCalleeContext() == SF) 112 break; 113 } 114 115 if (Node->pred_empty()) 116 return std::make_pair(nullptr, nullptr); 117 118 Node = *Node->pred_begin(); 119 } 120 121 return std::make_pair(S, Blk); 122 } 123 124 /// Adjusts a return value when the called function's return type does not 125 /// match the caller's expression type. This can happen when a dynamic call 126 /// is devirtualized, and the overriding method has a covariant (more specific) 127 /// return type than the parent's method. For C++ objects, this means we need 128 /// to add base casts. 129 static SVal adjustReturnValue(SVal V, QualType ExpectedTy, QualType ActualTy, 130 StoreManager &StoreMgr) { 131 // For now, the only adjustments we handle apply only to locations. 132 if (!isa<Loc>(V)) 133 return V; 134 135 // If the types already match, don't do any unnecessary work. 136 ExpectedTy = ExpectedTy.getCanonicalType(); 137 ActualTy = ActualTy.getCanonicalType(); 138 if (ExpectedTy == ActualTy) 139 return V; 140 141 // No adjustment is needed between Objective-C pointer types. 142 if (ExpectedTy->isObjCObjectPointerType() && 143 ActualTy->isObjCObjectPointerType()) 144 return V; 145 146 // C++ object pointers may need "derived-to-base" casts. 147 const CXXRecordDecl *ExpectedClass = ExpectedTy->getPointeeCXXRecordDecl(); 148 const CXXRecordDecl *ActualClass = ActualTy->getPointeeCXXRecordDecl(); 149 if (ExpectedClass && ActualClass) { 150 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 151 /*DetectVirtual=*/false); 152 if (ActualClass->isDerivedFrom(ExpectedClass, Paths) && 153 !Paths.isAmbiguous(ActualTy->getCanonicalTypeUnqualified())) { 154 return StoreMgr.evalDerivedToBase(V, Paths.front()); 155 } 156 } 157 158 // Unfortunately, Objective-C does not enforce that overridden methods have 159 // covariant return types, so we can't assert that that never happens. 160 // Be safe and return UnknownVal(). 161 return UnknownVal(); 162 } 163 164 void ExprEngine::removeDeadOnEndOfFunction(NodeBuilderContext& BC, 165 ExplodedNode *Pred, 166 ExplodedNodeSet &Dst) { 167 // Find the last statement in the function and the corresponding basic block. 168 const Stmt *LastSt = nullptr; 169 const CFGBlock *Blk = nullptr; 170 std::tie(LastSt, Blk) = getLastStmt(Pred); 171 if (!Blk || !LastSt) { 172 Dst.Add(Pred); 173 return; 174 } 175 176 // Here, we destroy the current location context. We use the current 177 // function's entire body as a diagnostic statement, with which the program 178 // point will be associated. However, we only want to use LastStmt as a 179 // reference for what to clean up if it's a ReturnStmt; otherwise, everything 180 // is dead. 181 SaveAndRestore<const NodeBuilderContext *> NodeContextRAII(currBldrCtx, &BC); 182 const LocationContext *LCtx = Pred->getLocationContext(); 183 removeDead(Pred, Dst, dyn_cast<ReturnStmt>(LastSt), LCtx, 184 LCtx->getAnalysisDeclContext()->getBody(), 185 ProgramPoint::PostStmtPurgeDeadSymbolsKind); 186 } 187 188 static bool wasDifferentDeclUsedForInlining(CallEventRef<> Call, 189 const StackFrameContext *calleeCtx) { 190 const Decl *RuntimeCallee = calleeCtx->getDecl(); 191 const Decl *StaticDecl = Call->getDecl(); 192 assert(RuntimeCallee); 193 if (!StaticDecl) 194 return true; 195 return RuntimeCallee->getCanonicalDecl() != StaticDecl->getCanonicalDecl(); 196 } 197 198 /// The call exit is simulated with a sequence of nodes, which occur between 199 /// CallExitBegin and CallExitEnd. The following operations occur between the 200 /// two program points: 201 /// 1. CallExitBegin (triggers the start of call exit sequence) 202 /// 2. Bind the return value 203 /// 3. Run Remove dead bindings to clean up the dead symbols from the callee. 204 /// 4. CallExitEnd (switch to the caller context) 205 /// 5. PostStmt<CallExpr> 206 void ExprEngine::processCallExit(ExplodedNode *CEBNode) { 207 // Step 1 CEBNode was generated before the call. 208 PrettyStackTraceLocationContext CrashInfo(CEBNode->getLocationContext()); 209 const StackFrameContext *calleeCtx = CEBNode->getStackFrame(); 210 211 // The parent context might not be a stack frame, so make sure we 212 // look up the first enclosing stack frame. 213 const StackFrameContext *callerCtx = 214 calleeCtx->getParent()->getStackFrame(); 215 216 const Stmt *CE = calleeCtx->getCallSite(); 217 ProgramStateRef state = CEBNode->getState(); 218 // Find the last statement in the function and the corresponding basic block. 219 const Stmt *LastSt = nullptr; 220 const CFGBlock *Blk = nullptr; 221 std::tie(LastSt, Blk) = getLastStmt(CEBNode); 222 223 // Generate a CallEvent /before/ cleaning the state, so that we can get the 224 // correct value for 'this' (if necessary). 225 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 226 CallEventRef<> Call = CEMgr.getCaller(calleeCtx, state); 227 228 // Step 2: generate node with bound return value: CEBNode -> BindedRetNode. 229 230 // If the callee returns an expression, bind its value to CallExpr. 231 if (CE) { 232 if (const ReturnStmt *RS = dyn_cast_or_null<ReturnStmt>(LastSt)) { 233 const LocationContext *LCtx = CEBNode->getLocationContext(); 234 SVal V = state->getSVal(RS, LCtx); 235 236 // Ensure that the return type matches the type of the returned Expr. 237 if (wasDifferentDeclUsedForInlining(Call, calleeCtx)) { 238 QualType ReturnedTy = 239 CallEvent::getDeclaredResultType(calleeCtx->getDecl()); 240 if (!ReturnedTy.isNull()) { 241 if (const Expr *Ex = dyn_cast<Expr>(CE)) { 242 V = adjustReturnValue(V, Ex->getType(), ReturnedTy, 243 getStoreManager()); 244 } 245 } 246 } 247 248 state = state->BindExpr(CE, callerCtx, V); 249 } 250 251 // Bind the constructed object value to CXXConstructExpr. 252 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(CE)) { 253 loc::MemRegionVal This = 254 svalBuilder.getCXXThis(CCE->getConstructor()->getParent(), calleeCtx); 255 SVal ThisV = state->getSVal(This); 256 ThisV = state->getSVal(ThisV.castAs<Loc>()); 257 state = state->BindExpr(CCE, callerCtx, ThisV); 258 } 259 260 if (const auto *CNE = dyn_cast<CXXNewExpr>(CE)) { 261 // We are currently evaluating a CXXNewAllocator CFGElement. It takes a 262 // while to reach the actual CXXNewExpr element from here, so keep the 263 // region for later use. 264 // Additionally cast the return value of the inlined operator new 265 // (which is of type 'void *') to the correct object type. 266 SVal AllocV = state->getSVal(CNE, callerCtx); 267 AllocV = svalBuilder.evalCast( 268 AllocV, CNE->getType(), 269 getContext().getPointerType(getContext().VoidTy)); 270 271 state = addObjectUnderConstruction(state, CNE, calleeCtx->getParent(), 272 AllocV); 273 } 274 } 275 276 // Step 3: BindedRetNode -> CleanedNodes 277 // If we can find a statement and a block in the inlined function, run remove 278 // dead bindings before returning from the call. This is important to ensure 279 // that we report the issues such as leaks in the stack contexts in which 280 // they occurred. 281 ExplodedNodeSet CleanedNodes; 282 if (LastSt && Blk && AMgr.options.AnalysisPurgeOpt != PurgeNone) { 283 static SimpleProgramPointTag retValBind("ExprEngine", "Bind Return Value"); 284 PostStmt Loc(LastSt, calleeCtx, &retValBind); 285 bool isNew; 286 ExplodedNode *BindedRetNode = G.getNode(Loc, state, false, &isNew); 287 BindedRetNode->addPredecessor(CEBNode, G); 288 if (!isNew) 289 return; 290 291 NodeBuilderContext Ctx(getCoreEngine(), Blk, BindedRetNode); 292 currBldrCtx = &Ctx; 293 // Here, we call the Symbol Reaper with 0 statement and callee location 294 // context, telling it to clean up everything in the callee's context 295 // (and its children). We use the callee's function body as a diagnostic 296 // statement, with which the program point will be associated. 297 removeDead(BindedRetNode, CleanedNodes, nullptr, calleeCtx, 298 calleeCtx->getAnalysisDeclContext()->getBody(), 299 ProgramPoint::PostStmtPurgeDeadSymbolsKind); 300 currBldrCtx = nullptr; 301 } else { 302 CleanedNodes.Add(CEBNode); 303 } 304 305 for (ExplodedNodeSet::iterator I = CleanedNodes.begin(), 306 E = CleanedNodes.end(); I != E; ++I) { 307 308 // Step 4: Generate the CallExit and leave the callee's context. 309 // CleanedNodes -> CEENode 310 CallExitEnd Loc(calleeCtx, callerCtx); 311 bool isNew; 312 ProgramStateRef CEEState = (*I == CEBNode) ? state : (*I)->getState(); 313 314 ExplodedNode *CEENode = G.getNode(Loc, CEEState, false, &isNew); 315 CEENode->addPredecessor(*I, G); 316 if (!isNew) 317 return; 318 319 // Step 5: Perform the post-condition check of the CallExpr and enqueue the 320 // result onto the work list. 321 // CEENode -> Dst -> WorkList 322 NodeBuilderContext Ctx(Engine, calleeCtx->getCallSiteBlock(), CEENode); 323 SaveAndRestore<const NodeBuilderContext*> NBCSave(currBldrCtx, 324 &Ctx); 325 SaveAndRestore<unsigned> CBISave(currStmtIdx, calleeCtx->getIndex()); 326 327 CallEventRef<> UpdatedCall = Call.cloneWithState(CEEState); 328 329 ExplodedNodeSet DstPostCall; 330 if (llvm::isa_and_nonnull<CXXNewExpr>(CE)) { 331 ExplodedNodeSet DstPostPostCallCallback; 332 getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback, 333 CEENode, *UpdatedCall, *this, 334 /*wasInlined=*/true); 335 for (ExplodedNode *I : DstPostPostCallCallback) { 336 getCheckerManager().runCheckersForNewAllocator( 337 cast<CXXAllocatorCall>(*UpdatedCall), 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 REGISTER_TRAIT_WITH_PROGRAMSTATE(CTUDispatchBifurcation, bool) 431 432 void ExprEngine::ctuBifurcate(const CallEvent &Call, const Decl *D, 433 NodeBuilder &Bldr, ExplodedNode *Pred, 434 ProgramStateRef State) { 435 ProgramStateRef ConservativeEvalState = nullptr; 436 if (Call.isForeign() && !isSecondPhaseCTU()) { 437 const auto IK = AMgr.options.getCTUPhase1Inlining(); 438 const bool DoInline = IK == CTUPhase1InliningKind::All || 439 (IK == CTUPhase1InliningKind::Small && 440 isSmall(AMgr.getAnalysisDeclContext(D))); 441 if (DoInline) { 442 inlineCall(Engine.getWorkList(), Call, D, Bldr, Pred, State); 443 return; 444 } 445 const bool BState = State->get<CTUDispatchBifurcation>(); 446 if (!BState) { // This is the first time we see this foreign function. 447 // Enqueue it to be analyzed in the second (ctu) phase. 448 inlineCall(Engine.getCTUWorkList(), Call, D, Bldr, Pred, State); 449 // Conservatively evaluate in the first phase. 450 ConservativeEvalState = State->set<CTUDispatchBifurcation>(true); 451 conservativeEvalCall(Call, Bldr, Pred, ConservativeEvalState); 452 } else { 453 conservativeEvalCall(Call, Bldr, Pred, State); 454 } 455 return; 456 } 457 inlineCall(Engine.getWorkList(), Call, D, Bldr, Pred, State); 458 } 459 460 void ExprEngine::inlineCall(WorkList *WList, const CallEvent &Call, 461 const Decl *D, NodeBuilder &Bldr, 462 ExplodedNode *Pred, ProgramStateRef State) { 463 assert(D); 464 465 const LocationContext *CurLC = Pred->getLocationContext(); 466 const StackFrameContext *CallerSFC = CurLC->getStackFrame(); 467 const LocationContext *ParentOfCallee = CallerSFC; 468 if (Call.getKind() == CE_Block && 469 !cast<BlockCall>(Call).isConversionFromLambda()) { 470 const BlockDataRegion *BR = cast<BlockCall>(Call).getBlockRegion(); 471 assert(BR && "If we have the block definition we should have its region"); 472 AnalysisDeclContext *BlockCtx = AMgr.getAnalysisDeclContext(D); 473 ParentOfCallee = BlockCtx->getBlockInvocationContext(CallerSFC, 474 cast<BlockDecl>(D), 475 BR); 476 } 477 478 // This may be NULL, but that's fine. 479 const Expr *CallE = Call.getOriginExpr(); 480 481 // Construct a new stack frame for the callee. 482 AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(D); 483 const StackFrameContext *CalleeSFC = 484 CalleeADC->getStackFrame(ParentOfCallee, CallE, currBldrCtx->getBlock(), 485 currBldrCtx->blockCount(), currStmtIdx); 486 487 CallEnter Loc(CallE, CalleeSFC, CurLC); 488 489 // Construct a new state which contains the mapping from actual to 490 // formal arguments. 491 State = State->enterStackFrame(Call, CalleeSFC); 492 493 bool isNew; 494 if (ExplodedNode *N = G.getNode(Loc, State, false, &isNew)) { 495 N->addPredecessor(Pred, G); 496 if (isNew) 497 WList->enqueue(N); 498 } 499 500 // If we decided to inline the call, the successor has been manually 501 // added onto the work list so remove it from the node builder. 502 Bldr.takeNodes(Pred); 503 504 NumInlinedCalls++; 505 Engine.FunctionSummaries->bumpNumTimesInlined(D); 506 507 // Do not mark as visited in the 2nd run (CTUWList), so the function will 508 // be visited as top-level, this way we won't loose reports in non-ctu 509 // mode. Considering the case when a function in a foreign TU calls back 510 // into the main TU. 511 // Note, during the 1st run, it doesn't matter if we mark the foreign 512 // functions as visited (or not) because they can never appear as a top level 513 // function in the main TU. 514 if (!isSecondPhaseCTU()) 515 // Mark the decl as visited. 516 if (VisitedCallees) 517 VisitedCallees->insert(D); 518 } 519 520 static ProgramStateRef getInlineFailedState(ProgramStateRef State, 521 const Stmt *CallE) { 522 const void *ReplayState = State->get<ReplayWithoutInlining>(); 523 if (!ReplayState) 524 return nullptr; 525 526 assert(ReplayState == CallE && "Backtracked to the wrong call."); 527 (void)CallE; 528 529 return State->remove<ReplayWithoutInlining>(); 530 } 531 532 void ExprEngine::VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred, 533 ExplodedNodeSet &dst) { 534 // Perform the previsit of the CallExpr. 535 ExplodedNodeSet dstPreVisit; 536 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, CE, *this); 537 538 // Get the call in its initial state. We use this as a template to perform 539 // all the checks. 540 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 541 CallEventRef<> CallTemplate 542 = CEMgr.getSimpleCall(CE, Pred->getState(), Pred->getLocationContext()); 543 544 // Evaluate the function call. We try each of the checkers 545 // to see if the can evaluate the function call. 546 ExplodedNodeSet dstCallEvaluated; 547 for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end(); 548 I != E; ++I) { 549 evalCall(dstCallEvaluated, *I, *CallTemplate); 550 } 551 552 // Finally, perform the post-condition check of the CallExpr and store 553 // the created nodes in 'Dst'. 554 // Note that if the call was inlined, dstCallEvaluated will be empty. 555 // The post-CallExpr check will occur in processCallExit. 556 getCheckerManager().runCheckersForPostStmt(dst, dstCallEvaluated, CE, 557 *this); 558 } 559 560 ProgramStateRef ExprEngine::finishArgumentConstruction(ProgramStateRef State, 561 const CallEvent &Call) { 562 const Expr *E = Call.getOriginExpr(); 563 // FIXME: Constructors to placement arguments of operator new 564 // are not supported yet. 565 if (!E || isa<CXXNewExpr>(E)) 566 return State; 567 568 const LocationContext *LC = Call.getLocationContext(); 569 for (unsigned CallI = 0, CallN = Call.getNumArgs(); CallI != CallN; ++CallI) { 570 unsigned I = Call.getASTArgumentIndex(CallI); 571 if (Optional<SVal> V = 572 getObjectUnderConstruction(State, {E, I}, LC)) { 573 SVal VV = *V; 574 (void)VV; 575 assert(cast<VarRegion>(VV.castAs<loc::MemRegionVal>().getRegion()) 576 ->getStackFrame()->getParent() 577 ->getStackFrame() == LC->getStackFrame()); 578 State = finishObjectConstruction(State, {E, I}, LC); 579 } 580 } 581 582 return State; 583 } 584 585 void ExprEngine::finishArgumentConstruction(ExplodedNodeSet &Dst, 586 ExplodedNode *Pred, 587 const CallEvent &Call) { 588 ProgramStateRef State = Pred->getState(); 589 ProgramStateRef CleanedState = finishArgumentConstruction(State, Call); 590 if (CleanedState == State) { 591 Dst.insert(Pred); 592 return; 593 } 594 595 const Expr *E = Call.getOriginExpr(); 596 const LocationContext *LC = Call.getLocationContext(); 597 NodeBuilder B(Pred, Dst, *currBldrCtx); 598 static SimpleProgramPointTag Tag("ExprEngine", 599 "Finish argument construction"); 600 PreStmt PP(E, LC, &Tag); 601 B.generateNode(PP, CleanedState, Pred); 602 } 603 604 void ExprEngine::evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred, 605 const CallEvent &Call) { 606 // WARNING: At this time, the state attached to 'Call' may be older than the 607 // state in 'Pred'. This is a minor optimization since CheckerManager will 608 // use an updated CallEvent instance when calling checkers, but if 'Call' is 609 // ever used directly in this function all callers should be updated to pass 610 // the most recent state. (It is probably not worth doing the work here since 611 // for some callers this will not be necessary.) 612 613 // Run any pre-call checks using the generic call interface. 614 ExplodedNodeSet dstPreVisit; 615 getCheckerManager().runCheckersForPreCall(dstPreVisit, Pred, 616 Call, *this); 617 618 // Actually evaluate the function call. We try each of the checkers 619 // to see if the can evaluate the function call, and get a callback at 620 // defaultEvalCall if all of them fail. 621 ExplodedNodeSet dstCallEvaluated; 622 getCheckerManager().runCheckersForEvalCall(dstCallEvaluated, dstPreVisit, 623 Call, *this, EvalCallOptions()); 624 625 // If there were other constructors called for object-type arguments 626 // of this call, clean them up. 627 ExplodedNodeSet dstArgumentCleanup; 628 for (ExplodedNode *I : dstCallEvaluated) 629 finishArgumentConstruction(dstArgumentCleanup, I, Call); 630 631 ExplodedNodeSet dstPostCall; 632 getCheckerManager().runCheckersForPostCall(dstPostCall, dstArgumentCleanup, 633 Call, *this); 634 635 // Escaping symbols conjured during invalidating the regions above. 636 // Note that, for inlined calls the nodes were put back into the worklist, 637 // so we can assume that every node belongs to a conservative call at this 638 // point. 639 640 // Run pointerEscape callback with the newly conjured symbols. 641 SmallVector<std::pair<SVal, SVal>, 8> Escaped; 642 for (ExplodedNode *I : dstPostCall) { 643 NodeBuilder B(I, Dst, *currBldrCtx); 644 ProgramStateRef State = I->getState(); 645 Escaped.clear(); 646 { 647 unsigned Arg = -1; 648 for (const ParmVarDecl *PVD : Call.parameters()) { 649 ++Arg; 650 QualType ParamTy = PVD->getType(); 651 if (ParamTy.isNull() || 652 (!ParamTy->isPointerType() && !ParamTy->isReferenceType())) 653 continue; 654 QualType Pointee = ParamTy->getPointeeType(); 655 if (Pointee.isConstQualified() || Pointee->isVoidType()) 656 continue; 657 if (const MemRegion *MR = Call.getArgSVal(Arg).getAsRegion()) 658 Escaped.emplace_back(loc::MemRegionVal(MR), State->getSVal(MR, Pointee)); 659 } 660 } 661 662 State = processPointerEscapedOnBind(State, Escaped, I->getLocationContext(), 663 PSK_EscapeOutParameters, &Call); 664 665 if (State == I->getState()) 666 Dst.insert(I); 667 else 668 B.generateNode(I->getLocation(), State, I); 669 } 670 } 671 672 ProgramStateRef ExprEngine::bindReturnValue(const CallEvent &Call, 673 const LocationContext *LCtx, 674 ProgramStateRef State) { 675 const Expr *E = Call.getOriginExpr(); 676 if (!E) 677 return State; 678 679 // Some method families have known return values. 680 if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(&Call)) { 681 switch (Msg->getMethodFamily()) { 682 default: 683 break; 684 case OMF_autorelease: 685 case OMF_retain: 686 case OMF_self: { 687 // These methods return their receivers. 688 return State->BindExpr(E, LCtx, Msg->getReceiverSVal()); 689 } 690 } 691 } else if (const CXXConstructorCall *C = dyn_cast<CXXConstructorCall>(&Call)){ 692 SVal ThisV = C->getCXXThisVal(); 693 ThisV = State->getSVal(ThisV.castAs<Loc>()); 694 return State->BindExpr(E, LCtx, ThisV); 695 } 696 697 SVal R; 698 QualType ResultTy = Call.getResultType(); 699 unsigned Count = currBldrCtx->blockCount(); 700 if (auto RTC = getCurrentCFGElement().getAs<CFGCXXRecordTypedCall>()) { 701 // Conjure a temporary if the function returns an object by value. 702 SVal Target; 703 assert(RTC->getStmt() == Call.getOriginExpr()); 704 EvalCallOptions CallOpts; // FIXME: We won't really need those. 705 std::tie(State, Target) = 706 handleConstructionContext(Call.getOriginExpr(), State, LCtx, 707 RTC->getConstructionContext(), CallOpts); 708 const MemRegion *TargetR = Target.getAsRegion(); 709 assert(TargetR); 710 // Invalidate the region so that it didn't look uninitialized. If this is 711 // a field or element constructor, we do not want to invalidate 712 // the whole structure. Pointer escape is meaningless because 713 // the structure is a product of conservative evaluation 714 // and therefore contains nothing interesting at this point. 715 RegionAndSymbolInvalidationTraits ITraits; 716 ITraits.setTrait(TargetR, 717 RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 718 State = State->invalidateRegions(TargetR, E, Count, LCtx, 719 /* CausesPointerEscape=*/false, nullptr, 720 &Call, &ITraits); 721 722 R = State->getSVal(Target.castAs<Loc>(), E->getType()); 723 } else { 724 // Conjure a symbol if the return value is unknown. 725 726 // See if we need to conjure a heap pointer instead of 727 // a regular unknown pointer. 728 const auto *CNE = dyn_cast<CXXNewExpr>(E); 729 if (CNE && CNE->getOperatorNew()->isReplaceableGlobalAllocationFunction()) { 730 R = svalBuilder.getConjuredHeapSymbolVal(E, LCtx, Count); 731 const MemRegion *MR = R.getAsRegion()->StripCasts(); 732 733 // Store the extent of the allocated object(s). 734 SVal ElementCount; 735 if (const Expr *SizeExpr = CNE->getArraySize().value_or(nullptr)) { 736 ElementCount = State->getSVal(SizeExpr, LCtx); 737 } else { 738 ElementCount = svalBuilder.makeIntVal(1, /*IsUnsigned=*/true); 739 } 740 741 SVal ElementSize = getElementExtent(CNE->getAllocatedType(), svalBuilder); 742 743 SVal Size = 744 svalBuilder.evalBinOp(State, BO_Mul, ElementCount, ElementSize, 745 svalBuilder.getArrayIndexType()); 746 747 State = setDynamicExtent(State, MR, Size.castAs<DefinedOrUnknownSVal>(), 748 svalBuilder); 749 } else { 750 R = svalBuilder.conjureSymbolVal(nullptr, E, LCtx, ResultTy, Count); 751 } 752 } 753 return State->BindExpr(E, LCtx, R); 754 } 755 756 // Conservatively evaluate call by invalidating regions and binding 757 // a conjured return value. 758 void ExprEngine::conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr, 759 ExplodedNode *Pred, ProgramStateRef State) { 760 State = Call.invalidateRegions(currBldrCtx->blockCount(), State); 761 State = bindReturnValue(Call, Pred->getLocationContext(), State); 762 763 // And make the result node. 764 Bldr.generateNode(Call.getProgramPoint(), State, Pred); 765 } 766 767 ExprEngine::CallInlinePolicy 768 ExprEngine::mayInlineCallKind(const CallEvent &Call, const ExplodedNode *Pred, 769 AnalyzerOptions &Opts, 770 const EvalCallOptions &CallOpts) { 771 const LocationContext *CurLC = Pred->getLocationContext(); 772 const StackFrameContext *CallerSFC = CurLC->getStackFrame(); 773 switch (Call.getKind()) { 774 case CE_Function: 775 case CE_Block: 776 break; 777 case CE_CXXMember: 778 case CE_CXXMemberOperator: 779 if (!Opts.mayInlineCXXMemberFunction(CIMK_MemberFunctions)) 780 return CIP_DisallowedAlways; 781 break; 782 case CE_CXXConstructor: { 783 if (!Opts.mayInlineCXXMemberFunction(CIMK_Constructors)) 784 return CIP_DisallowedAlways; 785 786 const CXXConstructorCall &Ctor = cast<CXXConstructorCall>(Call); 787 788 const CXXConstructExpr *CtorExpr = Ctor.getOriginExpr(); 789 790 auto CCE = getCurrentCFGElement().getAs<CFGConstructor>(); 791 const ConstructionContext *CC = CCE ? CCE->getConstructionContext() 792 : nullptr; 793 794 if (llvm::isa_and_nonnull<NewAllocatedObjectConstructionContext>(CC) && 795 !Opts.MayInlineCXXAllocator) 796 return CIP_DisallowedOnce; 797 798 // FIXME: We don't handle constructors or destructors for arrays properly. 799 // Even once we do, we still need to be careful about implicitly-generated 800 // initializers for array fields in default move/copy constructors. 801 // We still allow construction into ElementRegion targets when they don't 802 // represent array elements. 803 if (CallOpts.IsArrayCtorOrDtor) 804 return CIP_DisallowedOnce; 805 806 // Inlining constructors requires including initializers in the CFG. 807 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); 808 assert(ADC->getCFGBuildOptions().AddInitializers && "No CFG initializers"); 809 (void)ADC; 810 811 // If the destructor is trivial, it's always safe to inline the constructor. 812 if (Ctor.getDecl()->getParent()->hasTrivialDestructor()) 813 break; 814 815 // For other types, only inline constructors if destructor inlining is 816 // also enabled. 817 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) 818 return CIP_DisallowedAlways; 819 820 if (CtorExpr->getConstructionKind() == CXXConstructExpr::CK_Complete) { 821 // If we don't handle temporary destructors, we shouldn't inline 822 // their constructors. 823 if (CallOpts.IsTemporaryCtorOrDtor && 824 !Opts.ShouldIncludeTemporaryDtorsInCFG) 825 return CIP_DisallowedOnce; 826 827 // If we did not find the correct this-region, it would be pointless 828 // to inline the constructor. Instead we will simply invalidate 829 // the fake temporary target. 830 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) 831 return CIP_DisallowedOnce; 832 833 // If the temporary is lifetime-extended by binding it to a reference-type 834 // field within an aggregate, automatic destructors don't work properly. 835 if (CallOpts.IsTemporaryLifetimeExtendedViaAggregate) 836 return CIP_DisallowedOnce; 837 } 838 839 break; 840 } 841 case CE_CXXInheritedConstructor: { 842 // This doesn't really increase the cost of inlining ever, because 843 // the stack frame of the inherited constructor is trivial. 844 return CIP_Allowed; 845 } 846 case CE_CXXDestructor: { 847 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) 848 return CIP_DisallowedAlways; 849 850 // Inlining destructors requires building the CFG correctly. 851 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); 852 assert(ADC->getCFGBuildOptions().AddImplicitDtors && "No CFG destructors"); 853 (void)ADC; 854 855 // FIXME: We don't handle constructors or destructors for arrays properly. 856 if (CallOpts.IsArrayCtorOrDtor) 857 return CIP_DisallowedOnce; 858 859 // Allow disabling temporary destructor inlining with a separate option. 860 if (CallOpts.IsTemporaryCtorOrDtor && 861 !Opts.MayInlineCXXTemporaryDtors) 862 return CIP_DisallowedOnce; 863 864 // If we did not find the correct this-region, it would be pointless 865 // to inline the destructor. Instead we will simply invalidate 866 // the fake temporary target. 867 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) 868 return CIP_DisallowedOnce; 869 break; 870 } 871 case CE_CXXDeallocator: 872 LLVM_FALLTHROUGH; 873 case CE_CXXAllocator: 874 if (Opts.MayInlineCXXAllocator) 875 break; 876 // Do not inline allocators until we model deallocators. 877 // This is unfortunate, but basically necessary for smart pointers and such. 878 return CIP_DisallowedAlways; 879 case CE_ObjCMessage: 880 if (!Opts.MayInlineObjCMethod) 881 return CIP_DisallowedAlways; 882 if (!(Opts.getIPAMode() == IPAK_DynamicDispatch || 883 Opts.getIPAMode() == IPAK_DynamicDispatchBifurcate)) 884 return CIP_DisallowedAlways; 885 break; 886 } 887 888 return CIP_Allowed; 889 } 890 891 /// Returns true if the given C++ class contains a member with the given name. 892 static bool hasMember(const ASTContext &Ctx, const CXXRecordDecl *RD, 893 StringRef Name) { 894 const IdentifierInfo &II = Ctx.Idents.get(Name); 895 return RD->hasMemberName(Ctx.DeclarationNames.getIdentifier(&II)); 896 } 897 898 /// Returns true if the given C++ class is a container or iterator. 899 /// 900 /// Our heuristic for this is whether it contains a method named 'begin()' or a 901 /// nested type named 'iterator' or 'iterator_category'. 902 static bool isContainerClass(const ASTContext &Ctx, const CXXRecordDecl *RD) { 903 return hasMember(Ctx, RD, "begin") || 904 hasMember(Ctx, RD, "iterator") || 905 hasMember(Ctx, RD, "iterator_category"); 906 } 907 908 /// Returns true if the given function refers to a method of a C++ container 909 /// or iterator. 910 /// 911 /// We generally do a poor job modeling most containers right now, and might 912 /// prefer not to inline their methods. 913 static bool isContainerMethod(const ASTContext &Ctx, 914 const FunctionDecl *FD) { 915 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) 916 return isContainerClass(Ctx, MD->getParent()); 917 return false; 918 } 919 920 /// Returns true if the given function is the destructor of a class named 921 /// "shared_ptr". 922 static bool isCXXSharedPtrDtor(const FunctionDecl *FD) { 923 const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(FD); 924 if (!Dtor) 925 return false; 926 927 const CXXRecordDecl *RD = Dtor->getParent(); 928 if (const IdentifierInfo *II = RD->getDeclName().getAsIdentifierInfo()) 929 if (II->isStr("shared_ptr")) 930 return true; 931 932 return false; 933 } 934 935 /// Returns true if the function in \p CalleeADC may be inlined in general. 936 /// 937 /// This checks static properties of the function, such as its signature and 938 /// CFG, to determine whether the analyzer should ever consider inlining it, 939 /// in any context. 940 bool ExprEngine::mayInlineDecl(AnalysisDeclContext *CalleeADC) const { 941 AnalyzerOptions &Opts = AMgr.getAnalyzerOptions(); 942 // FIXME: Do not inline variadic calls. 943 if (CallEvent::isVariadic(CalleeADC->getDecl())) 944 return false; 945 946 // Check certain C++-related inlining policies. 947 ASTContext &Ctx = CalleeADC->getASTContext(); 948 if (Ctx.getLangOpts().CPlusPlus) { 949 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeADC->getDecl())) { 950 // Conditionally control the inlining of template functions. 951 if (!Opts.MayInlineTemplateFunctions) 952 if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate) 953 return false; 954 955 // Conditionally control the inlining of C++ standard library functions. 956 if (!Opts.MayInlineCXXStandardLibrary) 957 if (Ctx.getSourceManager().isInSystemHeader(FD->getLocation())) 958 if (AnalysisDeclContext::isInStdNamespace(FD)) 959 return false; 960 961 // Conditionally control the inlining of methods on objects that look 962 // like C++ containers. 963 if (!Opts.MayInlineCXXContainerMethods) 964 if (!AMgr.isInCodeFile(FD->getLocation())) 965 if (isContainerMethod(Ctx, FD)) 966 return false; 967 968 // Conditionally control the inlining of the destructor of C++ shared_ptr. 969 // We don't currently do a good job modeling shared_ptr because we can't 970 // see the reference count, so treating as opaque is probably the best 971 // idea. 972 if (!Opts.MayInlineCXXSharedPtrDtor) 973 if (isCXXSharedPtrDtor(FD)) 974 return false; 975 } 976 } 977 978 // It is possible that the CFG cannot be constructed. 979 // Be safe, and check if the CalleeCFG is valid. 980 const CFG *CalleeCFG = CalleeADC->getCFG(); 981 if (!CalleeCFG) 982 return false; 983 984 // Do not inline large functions. 985 if (isHuge(CalleeADC)) 986 return false; 987 988 // It is possible that the live variables analysis cannot be 989 // run. If so, bail out. 990 if (!CalleeADC->getAnalysis<RelaxedLiveVariables>()) 991 return false; 992 993 return true; 994 } 995 996 bool ExprEngine::shouldInlineCall(const CallEvent &Call, const Decl *D, 997 const ExplodedNode *Pred, 998 const EvalCallOptions &CallOpts) { 999 if (!D) 1000 return false; 1001 1002 AnalysisManager &AMgr = getAnalysisManager(); 1003 AnalyzerOptions &Opts = AMgr.options; 1004 AnalysisDeclContextManager &ADCMgr = AMgr.getAnalysisDeclContextManager(); 1005 AnalysisDeclContext *CalleeADC = ADCMgr.getContext(D); 1006 1007 // The auto-synthesized bodies are essential to inline as they are 1008 // usually small and commonly used. Note: we should do this check early on to 1009 // ensure we always inline these calls. 1010 if (CalleeADC->isBodyAutosynthesized()) 1011 return true; 1012 1013 if (!AMgr.shouldInlineCall()) 1014 return false; 1015 1016 // Check if this function has been marked as non-inlinable. 1017 Optional<bool> MayInline = Engine.FunctionSummaries->mayInline(D); 1018 if (MayInline) { 1019 if (!MayInline.getValue()) 1020 return false; 1021 1022 } else { 1023 // We haven't actually checked the static properties of this function yet. 1024 // Do that now, and record our decision in the function summaries. 1025 if (mayInlineDecl(CalleeADC)) { 1026 Engine.FunctionSummaries->markMayInline(D); 1027 } else { 1028 Engine.FunctionSummaries->markShouldNotInline(D); 1029 return false; 1030 } 1031 } 1032 1033 // Check if we should inline a call based on its kind. 1034 // FIXME: this checks both static and dynamic properties of the call, which 1035 // means we're redoing a bit of work that could be cached in the function 1036 // summary. 1037 CallInlinePolicy CIP = mayInlineCallKind(Call, Pred, Opts, CallOpts); 1038 if (CIP != CIP_Allowed) { 1039 if (CIP == CIP_DisallowedAlways) { 1040 assert(!MayInline || *MayInline); 1041 Engine.FunctionSummaries->markShouldNotInline(D); 1042 } 1043 return false; 1044 } 1045 1046 // Do not inline if recursive or we've reached max stack frame count. 1047 bool IsRecursive = false; 1048 unsigned StackDepth = 0; 1049 examineStackFrames(D, Pred->getLocationContext(), IsRecursive, StackDepth); 1050 if ((StackDepth >= Opts.InlineMaxStackDepth) && 1051 (!isSmall(CalleeADC) || IsRecursive)) 1052 return false; 1053 1054 // Do not inline large functions too many times. 1055 if ((Engine.FunctionSummaries->getNumTimesInlined(D) > 1056 Opts.MaxTimesInlineLarge) && 1057 isLarge(CalleeADC)) { 1058 NumReachedInlineCountMax++; 1059 return false; 1060 } 1061 1062 if (HowToInline == Inline_Minimal && (!isSmall(CalleeADC) || IsRecursive)) 1063 return false; 1064 1065 return true; 1066 } 1067 1068 static bool isTrivialObjectAssignment(const CallEvent &Call) { 1069 const CXXInstanceCall *ICall = dyn_cast<CXXInstanceCall>(&Call); 1070 if (!ICall) 1071 return false; 1072 1073 const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(ICall->getDecl()); 1074 if (!MD) 1075 return false; 1076 if (!(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())) 1077 return false; 1078 1079 return MD->isTrivial(); 1080 } 1081 1082 void ExprEngine::defaultEvalCall(NodeBuilder &Bldr, ExplodedNode *Pred, 1083 const CallEvent &CallTemplate, 1084 const EvalCallOptions &CallOpts) { 1085 // Make sure we have the most recent state attached to the call. 1086 ProgramStateRef State = Pred->getState(); 1087 CallEventRef<> Call = CallTemplate.cloneWithState(State); 1088 1089 // Special-case trivial assignment operators. 1090 if (isTrivialObjectAssignment(*Call)) { 1091 performTrivialCopy(Bldr, Pred, *Call); 1092 return; 1093 } 1094 1095 // Try to inline the call. 1096 // The origin expression here is just used as a kind of checksum; 1097 // this should still be safe even for CallEvents that don't come from exprs. 1098 const Expr *E = Call->getOriginExpr(); 1099 1100 ProgramStateRef InlinedFailedState = getInlineFailedState(State, E); 1101 if (InlinedFailedState) { 1102 // If we already tried once and failed, make sure we don't retry later. 1103 State = InlinedFailedState; 1104 } else { 1105 RuntimeDefinition RD = Call->getRuntimeDefinition(); 1106 Call->setForeign(RD.isForeign()); 1107 const Decl *D = RD.getDecl(); 1108 if (shouldInlineCall(*Call, D, Pred, CallOpts)) { 1109 if (RD.mayHaveOtherDefinitions()) { 1110 AnalyzerOptions &Options = getAnalysisManager().options; 1111 1112 // Explore with and without inlining the call. 1113 if (Options.getIPAMode() == IPAK_DynamicDispatchBifurcate) { 1114 BifurcateCall(RD.getDispatchRegion(), *Call, D, Bldr, Pred); 1115 return; 1116 } 1117 1118 // Don't inline if we're not in any dynamic dispatch mode. 1119 if (Options.getIPAMode() != IPAK_DynamicDispatch) { 1120 conservativeEvalCall(*Call, Bldr, Pred, State); 1121 return; 1122 } 1123 } 1124 ctuBifurcate(*Call, D, Bldr, Pred, State); 1125 return; 1126 } 1127 } 1128 1129 // If we can't inline it, handle the return value and invalidate the regions. 1130 conservativeEvalCall(*Call, Bldr, Pred, State); 1131 } 1132 1133 void ExprEngine::BifurcateCall(const MemRegion *BifurReg, 1134 const CallEvent &Call, const Decl *D, 1135 NodeBuilder &Bldr, ExplodedNode *Pred) { 1136 assert(BifurReg); 1137 BifurReg = BifurReg->StripCasts(); 1138 1139 // Check if we've performed the split already - note, we only want 1140 // to split the path once per memory region. 1141 ProgramStateRef State = Pred->getState(); 1142 const unsigned *BState = 1143 State->get<DynamicDispatchBifurcationMap>(BifurReg); 1144 if (BState) { 1145 // If we are on "inline path", keep inlining if possible. 1146 if (*BState == DynamicDispatchModeInlined) 1147 ctuBifurcate(Call, D, Bldr, Pred, State); 1148 // If inline failed, or we are on the path where we assume we 1149 // don't have enough info about the receiver to inline, conjure the 1150 // return value and invalidate the regions. 1151 conservativeEvalCall(Call, Bldr, Pred, State); 1152 return; 1153 } 1154 1155 // If we got here, this is the first time we process a message to this 1156 // region, so split the path. 1157 ProgramStateRef IState = 1158 State->set<DynamicDispatchBifurcationMap>(BifurReg, 1159 DynamicDispatchModeInlined); 1160 ctuBifurcate(Call, D, Bldr, Pred, IState); 1161 1162 ProgramStateRef NoIState = 1163 State->set<DynamicDispatchBifurcationMap>(BifurReg, 1164 DynamicDispatchModeConservative); 1165 conservativeEvalCall(Call, Bldr, Pred, NoIState); 1166 1167 NumOfDynamicDispatchPathSplits++; 1168 } 1169 1170 void ExprEngine::VisitReturnStmt(const ReturnStmt *RS, ExplodedNode *Pred, 1171 ExplodedNodeSet &Dst) { 1172 ExplodedNodeSet dstPreVisit; 1173 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, RS, *this); 1174 1175 StmtNodeBuilder B(dstPreVisit, Dst, *currBldrCtx); 1176 1177 if (RS->getRetValue()) { 1178 for (ExplodedNodeSet::iterator it = dstPreVisit.begin(), 1179 ei = dstPreVisit.end(); it != ei; ++it) { 1180 B.generateNode(RS, *it, (*it)->getState()); 1181 } 1182 } 1183 } 1184