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
processCallEnter(NodeBuilderContext & BC,CallEnter CE,ExplodedNode * Pred)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*,
getLastStmt(const ExplodedNode * Node)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.
adjustReturnValue(SVal V,QualType ExpectedTy,QualType ActualTy,StoreManager & StoreMgr)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 (!V.getAs<Loc>())
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
removeDeadOnEndOfFunction(NodeBuilderContext & BC,ExplodedNode * Pred,ExplodedNodeSet & Dst)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
wasDifferentDeclUsedForInlining(CallEventRef<> Call,const StackFrameContext * calleeCtx)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>
processCallExit(ExplodedNode * CEBNode)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
isSmall(AnalysisDeclContext * ADC) const368 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
isLarge(AnalysisDeclContext * ADC) const378 bool ExprEngine::isLarge(AnalysisDeclContext *ADC) const {
379 const CFG *Cfg = ADC->getCFG();
380 return Cfg->size() >= AMgr.options.MinCFGSizeTreatFunctionsAsLarge;
381 }
382
isHuge(AnalysisDeclContext * ADC) const383 bool ExprEngine::isHuge(AnalysisDeclContext *ADC) const {
384 const CFG *Cfg = ADC->getCFG();
385 return Cfg->getNumBlockIDs() > AMgr.options.MaxInlinableSize;
386 }
387
examineStackFrames(const Decl * D,const LocationContext * LCtx,bool & IsRecursive,unsigned & StackDepth)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
REGISTER_MAP_WITH_PROGRAMSTATE(DynamicDispatchBifurcationMap,const MemRegion *,unsigned)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
getInlineFailedState(ProgramStateRef State,const Stmt * CallE)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
VisitCallExpr(const CallExpr * CE,ExplodedNode * Pred,ExplodedNodeSet & dst)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
finishArgumentConstruction(ProgramStateRef State,const CallEvent & Call)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
finishArgumentConstruction(ExplodedNodeSet & Dst,ExplodedNode * Pred,const CallEvent & Call)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
evalCall(ExplodedNodeSet & Dst,ExplodedNode * Pred,const CallEvent & Call)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, EvalCallOptions());
589
590 // If there were other constructors called for object-type arguments
591 // of this call, clean them up.
592 ExplodedNodeSet dstArgumentCleanup;
593 for (ExplodedNode *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 (ExplodedNode *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
bindReturnValue(const CallEvent & Call,const LocationContext * LCtx,ProgramStateRef State)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 handleConstructionContext(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 const auto *CNE = dyn_cast<CXXNewExpr>(E);
694 if (CNE && CNE->getOperatorNew()->isReplaceableGlobalAllocationFunction()) {
695 R = svalBuilder.getConjuredHeapSymbolVal(E, LCtx, Count);
696 const MemRegion *MR = R.getAsRegion()->StripCasts();
697
698 // Store the extent of the allocated object(s).
699 SVal ElementCount;
700 if (const Expr *SizeExpr = CNE->getArraySize().getValueOr(nullptr)) {
701 ElementCount = State->getSVal(SizeExpr, LCtx);
702 } else {
703 ElementCount = svalBuilder.makeIntVal(1, /*IsUnsigned=*/true);
704 }
705
706 SVal ElementSize = getElementExtent(CNE->getAllocatedType(), svalBuilder);
707
708 SVal Size =
709 svalBuilder.evalBinOp(State, BO_Mul, ElementCount, ElementSize,
710 svalBuilder.getArrayIndexType());
711
712 State = setDynamicExtent(State, MR, Size.castAs<DefinedOrUnknownSVal>(),
713 svalBuilder);
714 } else {
715 R = svalBuilder.conjureSymbolVal(nullptr, E, LCtx, ResultTy, Count);
716 }
717 }
718 return State->BindExpr(E, LCtx, R);
719 }
720
721 // Conservatively evaluate call by invalidating regions and binding
722 // a conjured return value.
conservativeEvalCall(const CallEvent & Call,NodeBuilder & Bldr,ExplodedNode * Pred,ProgramStateRef State)723 void ExprEngine::conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr,
724 ExplodedNode *Pred, ProgramStateRef State) {
725 State = Call.invalidateRegions(currBldrCtx->blockCount(), State);
726 State = bindReturnValue(Call, Pred->getLocationContext(), State);
727
728 // And make the result node.
729 Bldr.generateNode(Call.getProgramPoint(), State, Pred);
730 }
731
732 ExprEngine::CallInlinePolicy
mayInlineCallKind(const CallEvent & Call,const ExplodedNode * Pred,AnalyzerOptions & Opts,const EvalCallOptions & CallOpts)733 ExprEngine::mayInlineCallKind(const CallEvent &Call, const ExplodedNode *Pred,
734 AnalyzerOptions &Opts,
735 const EvalCallOptions &CallOpts) {
736 const LocationContext *CurLC = Pred->getLocationContext();
737 const StackFrameContext *CallerSFC = CurLC->getStackFrame();
738 switch (Call.getKind()) {
739 case CE_Function:
740 case CE_Block:
741 break;
742 case CE_CXXMember:
743 case CE_CXXMemberOperator:
744 if (!Opts.mayInlineCXXMemberFunction(CIMK_MemberFunctions))
745 return CIP_DisallowedAlways;
746 break;
747 case CE_CXXConstructor: {
748 if (!Opts.mayInlineCXXMemberFunction(CIMK_Constructors))
749 return CIP_DisallowedAlways;
750
751 const CXXConstructorCall &Ctor = cast<CXXConstructorCall>(Call);
752
753 const CXXConstructExpr *CtorExpr = Ctor.getOriginExpr();
754
755 auto CCE = getCurrentCFGElement().getAs<CFGConstructor>();
756 const ConstructionContext *CC = CCE ? CCE->getConstructionContext()
757 : nullptr;
758
759 if (llvm::isa_and_nonnull<NewAllocatedObjectConstructionContext>(CC) &&
760 !Opts.MayInlineCXXAllocator)
761 return CIP_DisallowedOnce;
762
763 // FIXME: We don't handle constructors or destructors for arrays properly.
764 // Even once we do, we still need to be careful about implicitly-generated
765 // initializers for array fields in default move/copy constructors.
766 // We still allow construction into ElementRegion targets when they don't
767 // represent array elements.
768 if (CallOpts.IsArrayCtorOrDtor)
769 return CIP_DisallowedOnce;
770
771 // Inlining constructors requires including initializers in the CFG.
772 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext();
773 assert(ADC->getCFGBuildOptions().AddInitializers && "No CFG initializers");
774 (void)ADC;
775
776 // If the destructor is trivial, it's always safe to inline the constructor.
777 if (Ctor.getDecl()->getParent()->hasTrivialDestructor())
778 break;
779
780 // For other types, only inline constructors if destructor inlining is
781 // also enabled.
782 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors))
783 return CIP_DisallowedAlways;
784
785 if (CtorExpr->getConstructionKind() == CXXConstructExpr::CK_Complete) {
786 // If we don't handle temporary destructors, we shouldn't inline
787 // their constructors.
788 if (CallOpts.IsTemporaryCtorOrDtor &&
789 !Opts.ShouldIncludeTemporaryDtorsInCFG)
790 return CIP_DisallowedOnce;
791
792 // If we did not find the correct this-region, it would be pointless
793 // to inline the constructor. Instead we will simply invalidate
794 // the fake temporary target.
795 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)
796 return CIP_DisallowedOnce;
797
798 // If the temporary is lifetime-extended by binding it to a reference-type
799 // field within an aggregate, automatic destructors don't work properly.
800 if (CallOpts.IsTemporaryLifetimeExtendedViaAggregate)
801 return CIP_DisallowedOnce;
802 }
803
804 break;
805 }
806 case CE_CXXInheritedConstructor: {
807 // This doesn't really increase the cost of inlining ever, because
808 // the stack frame of the inherited constructor is trivial.
809 return CIP_Allowed;
810 }
811 case CE_CXXDestructor: {
812 if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors))
813 return CIP_DisallowedAlways;
814
815 // Inlining destructors requires building the CFG correctly.
816 const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext();
817 assert(ADC->getCFGBuildOptions().AddImplicitDtors && "No CFG destructors");
818 (void)ADC;
819
820 // FIXME: We don't handle constructors or destructors for arrays properly.
821 if (CallOpts.IsArrayCtorOrDtor)
822 return CIP_DisallowedOnce;
823
824 // Allow disabling temporary destructor inlining with a separate option.
825 if (CallOpts.IsTemporaryCtorOrDtor &&
826 !Opts.MayInlineCXXTemporaryDtors)
827 return CIP_DisallowedOnce;
828
829 // If we did not find the correct this-region, it would be pointless
830 // to inline the destructor. Instead we will simply invalidate
831 // the fake temporary target.
832 if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)
833 return CIP_DisallowedOnce;
834 break;
835 }
836 case CE_CXXDeallocator:
837 LLVM_FALLTHROUGH;
838 case CE_CXXAllocator:
839 if (Opts.MayInlineCXXAllocator)
840 break;
841 // Do not inline allocators until we model deallocators.
842 // This is unfortunate, but basically necessary for smart pointers and such.
843 return CIP_DisallowedAlways;
844 case CE_ObjCMessage:
845 if (!Opts.MayInlineObjCMethod)
846 return CIP_DisallowedAlways;
847 if (!(Opts.getIPAMode() == IPAK_DynamicDispatch ||
848 Opts.getIPAMode() == IPAK_DynamicDispatchBifurcate))
849 return CIP_DisallowedAlways;
850 break;
851 }
852
853 return CIP_Allowed;
854 }
855
856 /// Returns true if the given C++ class contains a member with the given name.
hasMember(const ASTContext & Ctx,const CXXRecordDecl * RD,StringRef Name)857 static bool hasMember(const ASTContext &Ctx, const CXXRecordDecl *RD,
858 StringRef Name) {
859 const IdentifierInfo &II = Ctx.Idents.get(Name);
860 return RD->hasMemberName(Ctx.DeclarationNames.getIdentifier(&II));
861 }
862
863 /// Returns true if the given C++ class is a container or iterator.
864 ///
865 /// Our heuristic for this is whether it contains a method named 'begin()' or a
866 /// nested type named 'iterator' or 'iterator_category'.
isContainerClass(const ASTContext & Ctx,const CXXRecordDecl * RD)867 static bool isContainerClass(const ASTContext &Ctx, const CXXRecordDecl *RD) {
868 return hasMember(Ctx, RD, "begin") ||
869 hasMember(Ctx, RD, "iterator") ||
870 hasMember(Ctx, RD, "iterator_category");
871 }
872
873 /// Returns true if the given function refers to a method of a C++ container
874 /// or iterator.
875 ///
876 /// We generally do a poor job modeling most containers right now, and might
877 /// prefer not to inline their methods.
isContainerMethod(const ASTContext & Ctx,const FunctionDecl * FD)878 static bool isContainerMethod(const ASTContext &Ctx,
879 const FunctionDecl *FD) {
880 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
881 return isContainerClass(Ctx, MD->getParent());
882 return false;
883 }
884
885 /// Returns true if the given function is the destructor of a class named
886 /// "shared_ptr".
isCXXSharedPtrDtor(const FunctionDecl * FD)887 static bool isCXXSharedPtrDtor(const FunctionDecl *FD) {
888 const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(FD);
889 if (!Dtor)
890 return false;
891
892 const CXXRecordDecl *RD = Dtor->getParent();
893 if (const IdentifierInfo *II = RD->getDeclName().getAsIdentifierInfo())
894 if (II->isStr("shared_ptr"))
895 return true;
896
897 return false;
898 }
899
900 /// Returns true if the function in \p CalleeADC may be inlined in general.
901 ///
902 /// This checks static properties of the function, such as its signature and
903 /// CFG, to determine whether the analyzer should ever consider inlining it,
904 /// in any context.
mayInlineDecl(AnalysisDeclContext * CalleeADC) const905 bool ExprEngine::mayInlineDecl(AnalysisDeclContext *CalleeADC) const {
906 AnalyzerOptions &Opts = AMgr.getAnalyzerOptions();
907 // FIXME: Do not inline variadic calls.
908 if (CallEvent::isVariadic(CalleeADC->getDecl()))
909 return false;
910
911 // Check certain C++-related inlining policies.
912 ASTContext &Ctx = CalleeADC->getASTContext();
913 if (Ctx.getLangOpts().CPlusPlus) {
914 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeADC->getDecl())) {
915 // Conditionally control the inlining of template functions.
916 if (!Opts.MayInlineTemplateFunctions)
917 if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate)
918 return false;
919
920 // Conditionally control the inlining of C++ standard library functions.
921 if (!Opts.MayInlineCXXStandardLibrary)
922 if (Ctx.getSourceManager().isInSystemHeader(FD->getLocation()))
923 if (AnalysisDeclContext::isInStdNamespace(FD))
924 return false;
925
926 // Conditionally control the inlining of methods on objects that look
927 // like C++ containers.
928 if (!Opts.MayInlineCXXContainerMethods)
929 if (!AMgr.isInCodeFile(FD->getLocation()))
930 if (isContainerMethod(Ctx, FD))
931 return false;
932
933 // Conditionally control the inlining of the destructor of C++ shared_ptr.
934 // We don't currently do a good job modeling shared_ptr because we can't
935 // see the reference count, so treating as opaque is probably the best
936 // idea.
937 if (!Opts.MayInlineCXXSharedPtrDtor)
938 if (isCXXSharedPtrDtor(FD))
939 return false;
940 }
941 }
942
943 // It is possible that the CFG cannot be constructed.
944 // Be safe, and check if the CalleeCFG is valid.
945 const CFG *CalleeCFG = CalleeADC->getCFG();
946 if (!CalleeCFG)
947 return false;
948
949 // Do not inline large functions.
950 if (isHuge(CalleeADC))
951 return false;
952
953 // It is possible that the live variables analysis cannot be
954 // run. If so, bail out.
955 if (!CalleeADC->getAnalysis<RelaxedLiveVariables>())
956 return false;
957
958 return true;
959 }
960
shouldInlineCall(const CallEvent & Call,const Decl * D,const ExplodedNode * Pred,const EvalCallOptions & CallOpts)961 bool ExprEngine::shouldInlineCall(const CallEvent &Call, const Decl *D,
962 const ExplodedNode *Pred,
963 const EvalCallOptions &CallOpts) {
964 if (!D)
965 return false;
966
967 AnalysisManager &AMgr = getAnalysisManager();
968 AnalyzerOptions &Opts = AMgr.options;
969 AnalysisDeclContextManager &ADCMgr = AMgr.getAnalysisDeclContextManager();
970 AnalysisDeclContext *CalleeADC = ADCMgr.getContext(D);
971
972 // The auto-synthesized bodies are essential to inline as they are
973 // usually small and commonly used. Note: we should do this check early on to
974 // ensure we always inline these calls.
975 if (CalleeADC->isBodyAutosynthesized())
976 return true;
977
978 if (!AMgr.shouldInlineCall())
979 return false;
980
981 // Check if this function has been marked as non-inlinable.
982 Optional<bool> MayInline = Engine.FunctionSummaries->mayInline(D);
983 if (MayInline.hasValue()) {
984 if (!MayInline.getValue())
985 return false;
986
987 } else {
988 // We haven't actually checked the static properties of this function yet.
989 // Do that now, and record our decision in the function summaries.
990 if (mayInlineDecl(CalleeADC)) {
991 Engine.FunctionSummaries->markMayInline(D);
992 } else {
993 Engine.FunctionSummaries->markShouldNotInline(D);
994 return false;
995 }
996 }
997
998 // Check if we should inline a call based on its kind.
999 // FIXME: this checks both static and dynamic properties of the call, which
1000 // means we're redoing a bit of work that could be cached in the function
1001 // summary.
1002 CallInlinePolicy CIP = mayInlineCallKind(Call, Pred, Opts, CallOpts);
1003 if (CIP != CIP_Allowed) {
1004 if (CIP == CIP_DisallowedAlways) {
1005 assert(!MayInline.hasValue() || MayInline.getValue());
1006 Engine.FunctionSummaries->markShouldNotInline(D);
1007 }
1008 return false;
1009 }
1010
1011 // Do not inline if recursive or we've reached max stack frame count.
1012 bool IsRecursive = false;
1013 unsigned StackDepth = 0;
1014 examineStackFrames(D, Pred->getLocationContext(), IsRecursive, StackDepth);
1015 if ((StackDepth >= Opts.InlineMaxStackDepth) &&
1016 (!isSmall(CalleeADC) || IsRecursive))
1017 return false;
1018
1019 // Do not inline large functions too many times.
1020 if ((Engine.FunctionSummaries->getNumTimesInlined(D) >
1021 Opts.MaxTimesInlineLarge) &&
1022 isLarge(CalleeADC)) {
1023 NumReachedInlineCountMax++;
1024 return false;
1025 }
1026
1027 if (HowToInline == Inline_Minimal && (!isSmall(CalleeADC) || IsRecursive))
1028 return false;
1029
1030 return true;
1031 }
1032
isTrivialObjectAssignment(const CallEvent & Call)1033 static bool isTrivialObjectAssignment(const CallEvent &Call) {
1034 const CXXInstanceCall *ICall = dyn_cast<CXXInstanceCall>(&Call);
1035 if (!ICall)
1036 return false;
1037
1038 const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(ICall->getDecl());
1039 if (!MD)
1040 return false;
1041 if (!(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))
1042 return false;
1043
1044 return MD->isTrivial();
1045 }
1046
defaultEvalCall(NodeBuilder & Bldr,ExplodedNode * Pred,const CallEvent & CallTemplate,const EvalCallOptions & CallOpts)1047 void ExprEngine::defaultEvalCall(NodeBuilder &Bldr, ExplodedNode *Pred,
1048 const CallEvent &CallTemplate,
1049 const EvalCallOptions &CallOpts) {
1050 // Make sure we have the most recent state attached to the call.
1051 ProgramStateRef State = Pred->getState();
1052 CallEventRef<> Call = CallTemplate.cloneWithState(State);
1053
1054 // Special-case trivial assignment operators.
1055 if (isTrivialObjectAssignment(*Call)) {
1056 performTrivialCopy(Bldr, Pred, *Call);
1057 return;
1058 }
1059
1060 // Try to inline the call.
1061 // The origin expression here is just used as a kind of checksum;
1062 // this should still be safe even for CallEvents that don't come from exprs.
1063 const Expr *E = Call->getOriginExpr();
1064
1065 ProgramStateRef InlinedFailedState = getInlineFailedState(State, E);
1066 if (InlinedFailedState) {
1067 // If we already tried once and failed, make sure we don't retry later.
1068 State = InlinedFailedState;
1069 } else {
1070 RuntimeDefinition RD = Call->getRuntimeDefinition();
1071 const Decl *D = RD.getDecl();
1072 if (shouldInlineCall(*Call, D, Pred, CallOpts)) {
1073 if (RD.mayHaveOtherDefinitions()) {
1074 AnalyzerOptions &Options = getAnalysisManager().options;
1075
1076 // Explore with and without inlining the call.
1077 if (Options.getIPAMode() == IPAK_DynamicDispatchBifurcate) {
1078 BifurcateCall(RD.getDispatchRegion(), *Call, D, Bldr, Pred);
1079 return;
1080 }
1081
1082 // Don't inline if we're not in any dynamic dispatch mode.
1083 if (Options.getIPAMode() != IPAK_DynamicDispatch) {
1084 conservativeEvalCall(*Call, Bldr, Pred, State);
1085 return;
1086 }
1087 }
1088
1089 // We are not bifurcating and we do have a Decl, so just inline.
1090 if (inlineCall(*Call, D, Bldr, Pred, State))
1091 return;
1092 }
1093 }
1094
1095 // If we can't inline it, handle the return value and invalidate the regions.
1096 conservativeEvalCall(*Call, Bldr, Pred, State);
1097 }
1098
BifurcateCall(const MemRegion * BifurReg,const CallEvent & Call,const Decl * D,NodeBuilder & Bldr,ExplodedNode * Pred)1099 void ExprEngine::BifurcateCall(const MemRegion *BifurReg,
1100 const CallEvent &Call, const Decl *D,
1101 NodeBuilder &Bldr, ExplodedNode *Pred) {
1102 assert(BifurReg);
1103 BifurReg = BifurReg->StripCasts();
1104
1105 // Check if we've performed the split already - note, we only want
1106 // to split the path once per memory region.
1107 ProgramStateRef State = Pred->getState();
1108 const unsigned *BState =
1109 State->get<DynamicDispatchBifurcationMap>(BifurReg);
1110 if (BState) {
1111 // If we are on "inline path", keep inlining if possible.
1112 if (*BState == DynamicDispatchModeInlined)
1113 if (inlineCall(Call, D, Bldr, Pred, State))
1114 return;
1115 // If inline failed, or we are on the path where we assume we
1116 // don't have enough info about the receiver to inline, conjure the
1117 // return value and invalidate the regions.
1118 conservativeEvalCall(Call, Bldr, Pred, State);
1119 return;
1120 }
1121
1122 // If we got here, this is the first time we process a message to this
1123 // region, so split the path.
1124 ProgramStateRef IState =
1125 State->set<DynamicDispatchBifurcationMap>(BifurReg,
1126 DynamicDispatchModeInlined);
1127 inlineCall(Call, D, Bldr, Pred, IState);
1128
1129 ProgramStateRef NoIState =
1130 State->set<DynamicDispatchBifurcationMap>(BifurReg,
1131 DynamicDispatchModeConservative);
1132 conservativeEvalCall(Call, Bldr, Pred, NoIState);
1133
1134 NumOfDynamicDispatchPathSplits++;
1135 }
1136
VisitReturnStmt(const ReturnStmt * RS,ExplodedNode * Pred,ExplodedNodeSet & Dst)1137 void ExprEngine::VisitReturnStmt(const ReturnStmt *RS, ExplodedNode *Pred,
1138 ExplodedNodeSet &Dst) {
1139 ExplodedNodeSet dstPreVisit;
1140 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, RS, *this);
1141
1142 StmtNodeBuilder B(dstPreVisit, Dst, *currBldrCtx);
1143
1144 if (RS->getRetValue()) {
1145 for (ExplodedNodeSet::iterator it = dstPreVisit.begin(),
1146 ei = dstPreVisit.end(); it != ei; ++it) {
1147 B.generateNode(RS, *it, (*it)->getState());
1148 }
1149 }
1150 }
1151