1 //=-- ExprEngineCallAndReturn.cpp - Support for call/return -----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines ExprEngine's support for calls and returns.
12 //===----------------------------------------------------------------------===//
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"
26 using namespace clang;
29 #define DEBUG_TYPE "ExprEngine"
31 STATISTIC(NumOfDynamicDispatchPathSplits,
32 "The # of times we split the path due to imprecise dynamic dispatch info");
34 STATISTIC(NumInlinedCalls,
35 "The # of times we inlined a call");
37 STATISTIC(NumReachedInlineCountMax,
38 "The # of times we reached inline count maximum");
40 void ExprEngine::processCallEnter(NodeBuilderContext& BC, CallEnter CE,
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();
48 assert(Entry->empty());
49 assert(Entry->succ_size() == 1);
51 // Get the solitary successor.
52 const CFGBlock *Succ = *(Entry->succ_begin());
54 // Construct an edge representing the starting location in the callee.
55 BlockEdge Loc(Entry, Succ, calleeCtx);
57 ProgramStateRef state = Pred->getState();
59 // Construct a new node, notify checkers that analysis of the function has
60 // begun, and add the resultant nodes to the worklist.
62 ExplodedNode *Node = G.getNode(Loc, state, false, &isNew);
63 Node->addPredecessor(Pred, G);
65 ExplodedNodeSet DstBegin;
66 processBeginOfFunction(BC, Node, DstBegin, Loc);
67 Engine.enqueue(DstBegin);
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();
79 // Back up through the ExplodedGraph until we reach a statement node in this
82 const ProgramPoint &PP = Node->getLocation();
84 if (PP.getStackFrame() == SF) {
85 if (Optional<StmtPoint> SP = PP.getAs<StmtPoint>()) {
88 } else if (Optional<CallExitEnd> CEE = PP.getAs<CallExitEnd>()) {
89 S = CEE->getCalleeContext()->getCallSite();
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;
98 Node = Node->getFirstPred();
99 CE = Node->getLocationAs<CallEnter>();
100 } while (!CE || CE->getCalleeContext() != CEE->getCalleeContext());
102 // Continue searching the graph.
103 } else if (Optional<BlockEdge> BE = PP.getAs<BlockEdge>()) {
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)
112 if (Node->pred_empty())
113 return std::make_pair(nullptr, nullptr);
115 Node = *Node->pred_begin();
118 return std::make_pair(S, Blk);
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.
132 // If the types already match, don't do any unnecessary work.
133 ExpectedTy = ExpectedTy.getCanonicalType();
134 ActualTy = ActualTy.getCanonicalType();
135 if (ExpectedTy == ActualTy)
138 // No adjustment is needed between Objective-C pointer types.
139 if (ExpectedTy->isObjCObjectPointerType() &&
140 ActualTy->isObjCObjectPointerType())
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());
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().
161 void ExprEngine::removeDeadOnEndOfFunction(NodeBuilderContext& BC,
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) {
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
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);
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);
192 return RuntimeCallee->getCanonicalDecl() != StaticDecl->getCanonicalDecl();
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();
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();
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);
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);
225 // Step 2: generate node with bound return value: CEBNode -> BindedRetNode.
227 // If the callee returns an expression, bind its value to CallExpr.
229 if (const ReturnStmt *RS = dyn_cast_or_null<ReturnStmt>(LastSt)) {
230 const LocationContext *LCtx = CEBNode->getLocationContext();
231 SVal V = state->getSVal(RS, LCtx);
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,
245 state = state->BindExpr(CE, callerCtx, V);
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);
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));
268 state = addObjectUnderConstruction(state, CNE, calleeCtx->getParent(),
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
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);
283 ExplodedNode *BindedRetNode = G.getNode(Loc, state, false, &isNew);
284 BindedRetNode->addPredecessor(CEBNode, G);
288 NodeBuilderContext Ctx(getCoreEngine(), Blk, BindedRetNode);
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;
299 CleanedNodes.Add(CEBNode);
302 for (ExplodedNodeSet::iterator I = CleanedNodes.begin(),
303 E = CleanedNodes.end(); I != E; ++I) {
305 // Step 4: Generate the CallExit and leave the callee's context.
306 // CleanedNodes -> CEENode
307 CallExitEnd Loc(calleeCtx, callerCtx);
309 ProgramStateRef CEEState = (*I == CEBNode) ? state : (*I)->getState();
311 ExplodedNode *CEENode = G.getNode(Loc, CEEState, false, &isNew);
312 CEENode->addPredecessor(*I, G);
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,
322 SaveAndRestore<unsigned> CBISave(currStmtIdx, calleeCtx->getIndex());
324 CallEventRef<> UpdatedCall = Call.cloneWithState(CEEState);
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(
335 *getObjectUnderConstruction(I->getState(), CNE,
336 calleeCtx->getParent()),
337 DstPostCall, I, *this,
338 /*WasInlined=*/true);
341 getCheckerManager().runCheckersForPostCall(DstPostCall, CEENode,
343 /*WasInlined=*/true);
346 if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(Call)) {
347 getCheckerManager().runCheckersForPostObjCMessage(Dst, DstPostCall, *Msg,
349 /*WasInlined=*/true);
351 !(isa<CXXNewExpr>(CE) && // Called when visiting CXXNewExpr.
352 AMgr.getAnalyzerOptions().MayInlineCXXAllocator)) {
353 getCheckerManager().runCheckersForPostStmt(Dst, DstPostCall, CE,
354 *this, /*WasInlined=*/true);
356 Dst.insert(DstPostCall);
359 // Enqueue the next element in the block.
360 for (ExplodedNodeSet::iterator PSI = Dst.begin(), PSE = Dst.end();
362 Engine.getWorkList()->enqueue(*PSI, calleeCtx->getCallSiteBlock(),
363 calleeCtx->getIndex()+1);
368 void ExprEngine::examineStackFrames(const Decl *D, const LocationContext *LCtx,
369 bool &IsRecursive, unsigned &StackDepth) {
374 if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LCtx)) {
375 const Decl *DI = SFC->getDecl();
377 // Mark recursive (and mutually recursive) functions and always count
378 // them when measuring the stack depth.
382 LCtx = LCtx->getParent();
386 // Do not count the small functions when determining the stack depth.
387 AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(DI);
388 const CFG *CalleeCFG = CalleeADC->getCFG();
389 if (CalleeCFG->getNumBlockIDs() > AMgr.options.AlwaysInlineSize)
392 LCtx = LCtx->getParent();
396 // The GDM component containing the dynamic dispatch bifurcation info. When
397 // the exact type of the receiver is not known, we want to explore both paths -
398 // one on which we do inline it and the other one on which we don't. This is
399 // done to ensure we do not drop coverage.
400 // This is the map from the receiver region to a bool, specifying either we
401 // consider this region's information precise or not along the given path.
403 enum DynamicDispatchMode {
404 DynamicDispatchModeInlined = 1,
405 DynamicDispatchModeConservative
407 } // end anonymous namespace
409 REGISTER_MAP_WITH_PROGRAMSTATE(DynamicDispatchBifurcationMap,
410 const MemRegion *, unsigned)
412 bool ExprEngine::inlineCall(const CallEvent &Call, const Decl *D,
413 NodeBuilder &Bldr, ExplodedNode *Pred,
414 ProgramStateRef State) {
417 const LocationContext *CurLC = Pred->getLocationContext();
418 const StackFrameContext *CallerSFC = CurLC->getStackFrame();
419 const LocationContext *ParentOfCallee = CallerSFC;
420 if (Call.getKind() == CE_Block &&
421 !cast<BlockCall>(Call).isConversionFromLambda()) {
422 const BlockDataRegion *BR = cast<BlockCall>(Call).getBlockRegion();
423 assert(BR && "If we have the block definition we should have its region");
424 AnalysisDeclContext *BlockCtx = AMgr.getAnalysisDeclContext(D);
425 ParentOfCallee = BlockCtx->getBlockInvocationContext(CallerSFC,
430 // This may be NULL, but that's fine.
431 const Expr *CallE = Call.getOriginExpr();
433 // Construct a new stack frame for the callee.
434 AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(D);
435 const StackFrameContext *CalleeSFC =
436 CalleeADC->getStackFrame(ParentOfCallee, CallE,
437 currBldrCtx->getBlock(),
440 CallEnter Loc(CallE, CalleeSFC, CurLC);
442 // Construct a new state which contains the mapping from actual to
444 State = State->enterStackFrame(Call, CalleeSFC);
447 if (ExplodedNode *N = G.getNode(Loc, State, false, &isNew)) {
448 N->addPredecessor(Pred, G);
450 Engine.getWorkList()->enqueue(N);
453 // If we decided to inline the call, the successor has been manually
454 // added onto the work list so remove it from the node builder.
455 Bldr.takeNodes(Pred);
458 Engine.FunctionSummaries->bumpNumTimesInlined(D);
460 // Mark the decl as visited.
462 VisitedCallees->insert(D);
467 static ProgramStateRef getInlineFailedState(ProgramStateRef State,
469 const void *ReplayState = State->get<ReplayWithoutInlining>();
473 assert(ReplayState == CallE && "Backtracked to the wrong call.");
476 return State->remove<ReplayWithoutInlining>();
479 void ExprEngine::VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred,
480 ExplodedNodeSet &dst) {
481 // Perform the previsit of the CallExpr.
482 ExplodedNodeSet dstPreVisit;
483 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, CE, *this);
485 // Get the call in its initial state. We use this as a template to perform
487 CallEventManager &CEMgr = getStateManager().getCallEventManager();
488 CallEventRef<> CallTemplate
489 = CEMgr.getSimpleCall(CE, Pred->getState(), Pred->getLocationContext());
491 // Evaluate the function call. We try each of the checkers
492 // to see if the can evaluate the function call.
493 ExplodedNodeSet dstCallEvaluated;
494 for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end();
496 evalCall(dstCallEvaluated, *I, *CallTemplate);
499 // Finally, perform the post-condition check of the CallExpr and store
500 // the created nodes in 'Dst'.
501 // Note that if the call was inlined, dstCallEvaluated will be empty.
502 // The post-CallExpr check will occur in processCallExit.
503 getCheckerManager().runCheckersForPostStmt(dst, dstCallEvaluated, CE,
507 ProgramStateRef ExprEngine::finishArgumentConstruction(ProgramStateRef State,
508 const CallEvent &Call) {
509 const Expr *E = Call.getOriginExpr();
510 // FIXME: Constructors to placement arguments of operator new
511 // are not supported yet.
512 if (!E || isa<CXXNewExpr>(E))
515 const LocationContext *LC = Call.getLocationContext();
516 for (unsigned CallI = 0, CallN = Call.getNumArgs(); CallI != CallN; ++CallI) {
517 unsigned I = Call.getASTArgumentIndex(CallI);
518 if (Optional<SVal> V =
519 getObjectUnderConstruction(State, {E, I}, LC)) {
522 assert(cast<VarRegion>(VV.castAs<loc::MemRegionVal>().getRegion())
523 ->getStackFrame()->getParent()
524 ->getStackFrame() == LC->getStackFrame());
525 State = finishObjectConstruction(State, {E, I}, LC);
532 void ExprEngine::finishArgumentConstruction(ExplodedNodeSet &Dst,
534 const CallEvent &Call) {
535 ProgramStateRef State = Pred->getState();
536 ProgramStateRef CleanedState = finishArgumentConstruction(State, Call);
537 if (CleanedState == State) {
542 const Expr *E = Call.getOriginExpr();
543 const LocationContext *LC = Call.getLocationContext();
544 NodeBuilder B(Pred, Dst, *currBldrCtx);
545 static SimpleProgramPointTag Tag("ExprEngine",
546 "Finish argument construction");
547 PreStmt PP(E, LC, &Tag);
548 B.generateNode(PP, CleanedState, Pred);
551 void ExprEngine::evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred,
552 const CallEvent &Call) {
553 // WARNING: At this time, the state attached to 'Call' may be older than the
554 // state in 'Pred'. This is a minor optimization since CheckerManager will
555 // use an updated CallEvent instance when calling checkers, but if 'Call' is
556 // ever used directly in this function all callers should be updated to pass
557 // the most recent state. (It is probably not worth doing the work here since
558 // for some callers this will not be necessary.)
560 // Run any pre-call checks using the generic call interface.
561 ExplodedNodeSet dstPreVisit;
562 getCheckerManager().runCheckersForPreCall(dstPreVisit, Pred,
565 // Actually evaluate the function call. We try each of the checkers
566 // to see if the can evaluate the function call, and get a callback at
567 // defaultEvalCall if all of them fail.
568 ExplodedNodeSet dstCallEvaluated;
569 getCheckerManager().runCheckersForEvalCall(dstCallEvaluated, dstPreVisit,
572 // If there were other constructors called for object-type arguments
573 // of this call, clean them up.
574 ExplodedNodeSet dstArgumentCleanup;
575 for (auto I : dstCallEvaluated)
576 finishArgumentConstruction(dstArgumentCleanup, I, Call);
578 // Finally, run any post-call checks.
579 getCheckerManager().runCheckersForPostCall(Dst, dstArgumentCleanup,
583 ProgramStateRef ExprEngine::bindReturnValue(const CallEvent &Call,
584 const LocationContext *LCtx,
585 ProgramStateRef State) {
586 const Expr *E = Call.getOriginExpr();
590 // Some method families have known return values.
591 if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(&Call)) {
592 switch (Msg->getMethodFamily()) {
595 case OMF_autorelease:
598 // These methods return their receivers.
599 return State->BindExpr(E, LCtx, Msg->getReceiverSVal());
602 } else if (const CXXConstructorCall *C = dyn_cast<CXXConstructorCall>(&Call)){
603 SVal ThisV = C->getCXXThisVal();
604 ThisV = State->getSVal(ThisV.castAs<Loc>());
605 return State->BindExpr(E, LCtx, ThisV);
609 QualType ResultTy = Call.getResultType();
610 unsigned Count = currBldrCtx->blockCount();
611 if (auto RTC = getCurrentCFGElement().getAs<CFGCXXRecordTypedCall>()) {
612 // Conjure a temporary if the function returns an object by value.
614 assert(RTC->getStmt() == Call.getOriginExpr());
615 EvalCallOptions CallOpts; // FIXME: We won't really need those.
616 std::tie(State, Target) =
617 prepareForObjectConstruction(Call.getOriginExpr(), State, LCtx,
618 RTC->getConstructionContext(), CallOpts);
619 assert(Target.getAsRegion());
620 // Invalidate the region so that it didn't look uninitialized. Don't notify
622 State = State->invalidateRegions(Target.getAsRegion(), E, Count, LCtx,
623 /* CausedByPointerEscape=*/false, nullptr,
626 R = State->getSVal(Target.castAs<Loc>(), E->getType());
628 // Conjure a symbol if the return value is unknown.
630 // See if we need to conjure a heap pointer instead of
631 // a regular unknown pointer.
632 bool IsHeapPointer = false;
633 if (const auto *CNE = dyn_cast<CXXNewExpr>(E))
634 if (CNE->getOperatorNew()->isReplaceableGlobalAllocationFunction()) {
635 // FIXME: Delegate this to evalCall in MallocChecker?
636 IsHeapPointer = true;
639 R = IsHeapPointer ? svalBuilder.getConjuredHeapSymbolVal(E, LCtx, Count)
640 : svalBuilder.conjureSymbolVal(nullptr, E, LCtx, ResultTy,
643 return State->BindExpr(E, LCtx, R);
646 // Conservatively evaluate call by invalidating regions and binding
647 // a conjured return value.
648 void ExprEngine::conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr,
650 ProgramStateRef State) {
651 State = Call.invalidateRegions(currBldrCtx->blockCount(), State);
652 State = bindReturnValue(Call, Pred->getLocationContext(), State);
654 // And make the result node.
655 Bldr.generateNode(Call.getProgramPoint(), State, Pred);
658 ExprEngine::CallInlinePolicy
659 ExprEngine::mayInlineCallKind(const CallEvent &Call, const ExplodedNode *Pred,
660 AnalyzerOptions &Opts,
661 const ExprEngine::EvalCallOptions &CallOpts) {
662 const LocationContext *CurLC = Pred->getLocationContext();
663 const StackFrameContext *CallerSFC = CurLC->getStackFrame();
664 switch (Call.getKind()) {
669 case CE_CXXMemberOperator:
670 if (!Opts.mayInlineCXXMemberFunction(CIMK_MemberFunctions))
671 return CIP_DisallowedAlways;
673 case CE_CXXConstructor: {
674 if (!Opts.mayInlineCXXMemberFunction(CIMK_Constructors))
675 return CIP_DisallowedAlways;
677 const CXXConstructorCall &Ctor = cast<CXXConstructorCall>(Call);
679 const CXXConstructExpr *CtorExpr = Ctor.getOriginExpr();
681 auto CCE = getCurrentCFGElement().getAs<CFGConstructor>();
682 const ConstructionContext *CC = CCE ? CCE->getConstructionContext()
685 if (CC && isa<NewAllocatedObjectConstructionContext>(CC) &&
686 !Opts.MayInlineCXXAllocator)
687 return CIP_DisallowedOnce;
689 // FIXME: We don't handle constructors or destructors for arrays properly.
690 // Even once we do, we still need to be careful about implicitly-generated
691 // initializers for array fields in default move/copy constructors.
692 // We still allow construction into ElementRegion targets when they don't
693 // represent array elements.
694 if (CallOpts.IsArrayCtorOrDtor)
695 return CIP_DisallowedOnce;
697 // Inlining constructors requires including initializers in the CFG.
698 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext();
699 assert(ADC->getCFGBuildOptions().AddInitializers && "No CFG initializers");
702 // If the destructor is trivial, it's always safe to inline the constructor.
703 if (Ctor.getDecl()->getParent()->hasTrivialDestructor())
706 // For other types, only inline constructors if destructor inlining is
708 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors))
709 return CIP_DisallowedAlways;
711 if (CtorExpr->getConstructionKind() == CXXConstructExpr::CK_Complete) {
712 // If we don't handle temporary destructors, we shouldn't inline
713 // their constructors.
714 if (CallOpts.IsTemporaryCtorOrDtor &&
715 !Opts.ShouldIncludeTemporaryDtorsInCFG)
716 return CIP_DisallowedOnce;
718 // If we did not find the correct this-region, it would be pointless
719 // to inline the constructor. Instead we will simply invalidate
720 // the fake temporary target.
721 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)
722 return CIP_DisallowedOnce;
724 // If the temporary is lifetime-extended by binding it to a reference-type
725 // field within an aggregate, automatic destructors don't work properly.
726 if (CallOpts.IsTemporaryLifetimeExtendedViaAggregate)
727 return CIP_DisallowedOnce;
732 case CE_CXXDestructor: {
733 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors))
734 return CIP_DisallowedAlways;
736 // Inlining destructors requires building the CFG correctly.
737 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext();
738 assert(ADC->getCFGBuildOptions().AddImplicitDtors && "No CFG destructors");
741 // FIXME: We don't handle constructors or destructors for arrays properly.
742 if (CallOpts.IsArrayCtorOrDtor)
743 return CIP_DisallowedOnce;
745 // Allow disabling temporary destructor inlining with a separate option.
746 if (CallOpts.IsTemporaryCtorOrDtor &&
747 !Opts.MayInlineCXXTemporaryDtors)
748 return CIP_DisallowedOnce;
750 // If we did not find the correct this-region, it would be pointless
751 // to inline the destructor. Instead we will simply invalidate
752 // the fake temporary target.
753 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)
754 return CIP_DisallowedOnce;
757 case CE_CXXAllocator:
758 if (Opts.MayInlineCXXAllocator)
760 // Do not inline allocators until we model deallocators.
761 // This is unfortunate, but basically necessary for smart pointers and such.
762 return CIP_DisallowedAlways;
764 if (!Opts.MayInlineObjCMethod)
765 return CIP_DisallowedAlways;
766 if (!(Opts.getIPAMode() == IPAK_DynamicDispatch ||
767 Opts.getIPAMode() == IPAK_DynamicDispatchBifurcate))
768 return CIP_DisallowedAlways;
775 /// Returns true if the given C++ class contains a member with the given name.
776 static bool hasMember(const ASTContext &Ctx, const CXXRecordDecl *RD,
778 const IdentifierInfo &II = Ctx.Idents.get(Name);
779 DeclarationName DeclName = Ctx.DeclarationNames.getIdentifier(&II);
780 if (!RD->lookup(DeclName).empty())
783 CXXBasePaths Paths(false, false, false);
784 if (RD->lookupInBases(
785 [DeclName](const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
786 return CXXRecordDecl::FindOrdinaryMember(Specifier, Path, DeclName);
794 /// Returns true if the given C++ class is a container or iterator.
796 /// Our heuristic for this is whether it contains a method named 'begin()' or a
797 /// nested type named 'iterator' or 'iterator_category'.
798 static bool isContainerClass(const ASTContext &Ctx, const CXXRecordDecl *RD) {
799 return hasMember(Ctx, RD, "begin") ||
800 hasMember(Ctx, RD, "iterator") ||
801 hasMember(Ctx, RD, "iterator_category");
804 /// Returns true if the given function refers to a method of a C++ container
807 /// We generally do a poor job modeling most containers right now, and might
808 /// prefer not to inline their methods.
809 static bool isContainerMethod(const ASTContext &Ctx,
810 const FunctionDecl *FD) {
811 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
812 return isContainerClass(Ctx, MD->getParent());
816 /// Returns true if the given function is the destructor of a class named
818 static bool isCXXSharedPtrDtor(const FunctionDecl *FD) {
819 const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(FD);
823 const CXXRecordDecl *RD = Dtor->getParent();
824 if (const IdentifierInfo *II = RD->getDeclName().getAsIdentifierInfo())
825 if (II->isStr("shared_ptr"))
831 /// Returns true if the function in \p CalleeADC may be inlined in general.
833 /// This checks static properties of the function, such as its signature and
834 /// CFG, to determine whether the analyzer should ever consider inlining it,
836 static bool mayInlineDecl(AnalysisManager &AMgr,
837 AnalysisDeclContext *CalleeADC) {
838 AnalyzerOptions &Opts = AMgr.getAnalyzerOptions();
839 // FIXME: Do not inline variadic calls.
840 if (CallEvent::isVariadic(CalleeADC->getDecl()))
843 // Check certain C++-related inlining policies.
844 ASTContext &Ctx = CalleeADC->getASTContext();
845 if (Ctx.getLangOpts().CPlusPlus) {
846 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeADC->getDecl())) {
847 // Conditionally control the inlining of template functions.
848 if (!Opts.MayInlineTemplateFunctions)
849 if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate)
852 // Conditionally control the inlining of C++ standard library functions.
853 if (!Opts.MayInlineCXXStandardLibrary)
854 if (Ctx.getSourceManager().isInSystemHeader(FD->getLocation()))
855 if (AnalysisDeclContext::isInStdNamespace(FD))
858 // Conditionally control the inlining of methods on objects that look
859 // like C++ containers.
860 if (!Opts.MayInlineCXXContainerMethods)
861 if (!AMgr.isInCodeFile(FD->getLocation()))
862 if (isContainerMethod(Ctx, FD))
865 // Conditionally control the inlining of the destructor of C++ shared_ptr.
866 // We don't currently do a good job modeling shared_ptr because we can't
867 // see the reference count, so treating as opaque is probably the best
869 if (!Opts.MayInlineCXXSharedPtrDtor)
870 if (isCXXSharedPtrDtor(FD))
875 // It is possible that the CFG cannot be constructed.
876 // Be safe, and check if the CalleeCFG is valid.
877 const CFG *CalleeCFG = CalleeADC->getCFG();
881 // Do not inline large functions.
882 if (CalleeCFG->getNumBlockIDs() > Opts.MaxInlinableSize)
885 // It is possible that the live variables analysis cannot be
886 // run. If so, bail out.
887 if (!CalleeADC->getAnalysis<RelaxedLiveVariables>())
893 bool ExprEngine::shouldInlineCall(const CallEvent &Call, const Decl *D,
894 const ExplodedNode *Pred,
895 const EvalCallOptions &CallOpts) {
899 AnalysisManager &AMgr = getAnalysisManager();
900 AnalyzerOptions &Opts = AMgr.options;
901 AnalysisDeclContextManager &ADCMgr = AMgr.getAnalysisDeclContextManager();
902 AnalysisDeclContext *CalleeADC = ADCMgr.getContext(D);
904 // The auto-synthesized bodies are essential to inline as they are
905 // usually small and commonly used. Note: we should do this check early on to
906 // ensure we always inline these calls.
907 if (CalleeADC->isBodyAutosynthesized())
910 if (!AMgr.shouldInlineCall())
913 // Check if this function has been marked as non-inlinable.
914 Optional<bool> MayInline = Engine.FunctionSummaries->mayInline(D);
915 if (MayInline.hasValue()) {
916 if (!MayInline.getValue())
920 // We haven't actually checked the static properties of this function yet.
921 // Do that now, and record our decision in the function summaries.
922 if (mayInlineDecl(getAnalysisManager(), CalleeADC)) {
923 Engine.FunctionSummaries->markMayInline(D);
925 Engine.FunctionSummaries->markShouldNotInline(D);
930 // Check if we should inline a call based on its kind.
931 // FIXME: this checks both static and dynamic properties of the call, which
932 // means we're redoing a bit of work that could be cached in the function
934 CallInlinePolicy CIP = mayInlineCallKind(Call, Pred, Opts, CallOpts);
935 if (CIP != CIP_Allowed) {
936 if (CIP == CIP_DisallowedAlways) {
937 assert(!MayInline.hasValue() || MayInline.getValue());
938 Engine.FunctionSummaries->markShouldNotInline(D);
943 const CFG *CalleeCFG = CalleeADC->getCFG();
945 // Do not inline if recursive or we've reached max stack frame count.
946 bool IsRecursive = false;
947 unsigned StackDepth = 0;
948 examineStackFrames(D, Pred->getLocationContext(), IsRecursive, StackDepth);
949 if ((StackDepth >= Opts.InlineMaxStackDepth) &&
950 ((CalleeCFG->getNumBlockIDs() > Opts.AlwaysInlineSize)
954 // Do not inline large functions too many times.
955 if ((Engine.FunctionSummaries->getNumTimesInlined(D) >
956 Opts.MaxTimesInlineLarge) &&
957 CalleeCFG->getNumBlockIDs() >=
958 Opts.MinCFGSizeTreatFunctionsAsLarge) {
959 NumReachedInlineCountMax++;
963 if (HowToInline == Inline_Minimal &&
964 (CalleeCFG->getNumBlockIDs() > Opts.AlwaysInlineSize
971 static bool isTrivialObjectAssignment(const CallEvent &Call) {
972 const CXXInstanceCall *ICall = dyn_cast<CXXInstanceCall>(&Call);
976 const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(ICall->getDecl());
979 if (!(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))
982 return MD->isTrivial();
985 void ExprEngine::defaultEvalCall(NodeBuilder &Bldr, ExplodedNode *Pred,
986 const CallEvent &CallTemplate,
987 const EvalCallOptions &CallOpts) {
988 // Make sure we have the most recent state attached to the call.
989 ProgramStateRef State = Pred->getState();
990 CallEventRef<> Call = CallTemplate.cloneWithState(State);
992 // Special-case trivial assignment operators.
993 if (isTrivialObjectAssignment(*Call)) {
994 performTrivialCopy(Bldr, Pred, *Call);
998 // Try to inline the call.
999 // The origin expression here is just used as a kind of checksum;
1000 // this should still be safe even for CallEvents that don't come from exprs.
1001 const Expr *E = Call->getOriginExpr();
1003 ProgramStateRef InlinedFailedState = getInlineFailedState(State, E);
1004 if (InlinedFailedState) {
1005 // If we already tried once and failed, make sure we don't retry later.
1006 State = InlinedFailedState;
1008 RuntimeDefinition RD = Call->getRuntimeDefinition();
1009 const Decl *D = RD.getDecl();
1010 if (shouldInlineCall(*Call, D, Pred, CallOpts)) {
1011 if (RD.mayHaveOtherDefinitions()) {
1012 AnalyzerOptions &Options = getAnalysisManager().options;
1014 // Explore with and without inlining the call.
1015 if (Options.getIPAMode() == IPAK_DynamicDispatchBifurcate) {
1016 BifurcateCall(RD.getDispatchRegion(), *Call, D, Bldr, Pred);
1020 // Don't inline if we're not in any dynamic dispatch mode.
1021 if (Options.getIPAMode() != IPAK_DynamicDispatch) {
1022 conservativeEvalCall(*Call, Bldr, Pred, State);
1027 // We are not bifurcating and we do have a Decl, so just inline.
1028 if (inlineCall(*Call, D, Bldr, Pred, State))
1033 // If we can't inline it, handle the return value and invalidate the regions.
1034 conservativeEvalCall(*Call, Bldr, Pred, State);
1037 void ExprEngine::BifurcateCall(const MemRegion *BifurReg,
1038 const CallEvent &Call, const Decl *D,
1039 NodeBuilder &Bldr, ExplodedNode *Pred) {
1041 BifurReg = BifurReg->StripCasts();
1043 // Check if we've performed the split already - note, we only want
1044 // to split the path once per memory region.
1045 ProgramStateRef State = Pred->getState();
1046 const unsigned *BState =
1047 State->get<DynamicDispatchBifurcationMap>(BifurReg);
1049 // If we are on "inline path", keep inlining if possible.
1050 if (*BState == DynamicDispatchModeInlined)
1051 if (inlineCall(Call, D, Bldr, Pred, State))
1053 // If inline failed, or we are on the path where we assume we
1054 // don't have enough info about the receiver to inline, conjure the
1055 // return value and invalidate the regions.
1056 conservativeEvalCall(Call, Bldr, Pred, State);
1060 // If we got here, this is the first time we process a message to this
1061 // region, so split the path.
1062 ProgramStateRef IState =
1063 State->set<DynamicDispatchBifurcationMap>(BifurReg,
1064 DynamicDispatchModeInlined);
1065 inlineCall(Call, D, Bldr, Pred, IState);
1067 ProgramStateRef NoIState =
1068 State->set<DynamicDispatchBifurcationMap>(BifurReg,
1069 DynamicDispatchModeConservative);
1070 conservativeEvalCall(Call, Bldr, Pred, NoIState);
1072 NumOfDynamicDispatchPathSplits++;
1075 void ExprEngine::VisitReturnStmt(const ReturnStmt *RS, ExplodedNode *Pred,
1076 ExplodedNodeSet &Dst) {
1077 ExplodedNodeSet dstPreVisit;
1078 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, RS, *this);
1080 StmtNodeBuilder B(dstPreVisit, Dst, *currBldrCtx);
1082 if (RS->getRetValue()) {
1083 for (ExplodedNodeSet::iterator it = dstPreVisit.begin(),
1084 ei = dstPreVisit.end(); it != ei; ++it) {
1085 B.generateNode(RS, *it, (*it)->getState());