| //=-- ExprEngineCallAndReturn.cpp - Support for call/return -----*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines ExprEngine's support for calls and returns. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" |
| #include "PrettyStackTraceLocationContext.h" |
| #include "clang/AST/CXXInheritance.h" |
| #include "clang/AST/DeclCXX.h" |
| #include "clang/AST/ParentMap.h" |
| #include "clang/Analysis/Analyses/LiveVariables.h" |
| #include "clang/StaticAnalyzer/Core/CheckerManager.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/Support/SaveAndRestore.h" |
| |
| using namespace clang; |
| using namespace ento; |
| |
| #define DEBUG_TYPE "ExprEngine" |
| |
| STATISTIC(NumOfDynamicDispatchPathSplits, |
| "The # of times we split the path due to imprecise dynamic dispatch info"); |
| |
| STATISTIC(NumInlinedCalls, |
| "The # of times we inlined a call"); |
| |
| STATISTIC(NumReachedInlineCountMax, |
| "The # of times we reached inline count maximum"); |
| |
| void ExprEngine::processCallEnter(CallEnter CE, ExplodedNode *Pred) { |
| // Get the entry block in the CFG of the callee. |
| const StackFrameContext *calleeCtx = CE.getCalleeContext(); |
| PrettyStackTraceLocationContext CrashInfo(calleeCtx); |
| |
| const CFG *CalleeCFG = calleeCtx->getCFG(); |
| const CFGBlock *Entry = &(CalleeCFG->getEntry()); |
| |
| // Validate the CFG. |
| assert(Entry->empty()); |
| assert(Entry->succ_size() == 1); |
| |
| // Get the solitary successor. |
| const CFGBlock *Succ = *(Entry->succ_begin()); |
| |
| // Construct an edge representing the starting location in the callee. |
| BlockEdge Loc(Entry, Succ, calleeCtx); |
| |
| ProgramStateRef state = Pred->getState(); |
| |
| // Construct a new node and add it to the worklist. |
| bool isNew; |
| ExplodedNode *Node = G.getNode(Loc, state, false, &isNew); |
| Node->addPredecessor(Pred, G); |
| if (isNew) |
| Engine.getWorkList()->enqueue(Node); |
| } |
| |
| // Find the last statement on the path to the exploded node and the |
| // corresponding Block. |
| static std::pair<const Stmt*, |
| const CFGBlock*> getLastStmt(const ExplodedNode *Node) { |
| const Stmt *S = 0; |
| const CFGBlock *Blk = 0; |
| const StackFrameContext *SF = |
| Node->getLocation().getLocationContext()->getCurrentStackFrame(); |
| |
| // Back up through the ExplodedGraph until we reach a statement node in this |
| // stack frame. |
| while (Node) { |
| const ProgramPoint &PP = Node->getLocation(); |
| |
| if (PP.getLocationContext()->getCurrentStackFrame() == SF) { |
| if (Optional<StmtPoint> SP = PP.getAs<StmtPoint>()) { |
| S = SP->getStmt(); |
| break; |
| } else if (Optional<CallExitEnd> CEE = PP.getAs<CallExitEnd>()) { |
| S = CEE->getCalleeContext()->getCallSite(); |
| if (S) |
| break; |
| |
| // If there is no statement, this is an implicitly-generated call. |
| // We'll walk backwards over it and then continue the loop to find |
| // an actual statement. |
| Optional<CallEnter> CE; |
| do { |
| Node = Node->getFirstPred(); |
| CE = Node->getLocationAs<CallEnter>(); |
| } while (!CE || CE->getCalleeContext() != CEE->getCalleeContext()); |
| |
| // Continue searching the graph. |
| } else if (Optional<BlockEdge> BE = PP.getAs<BlockEdge>()) { |
| Blk = BE->getSrc(); |
| } |
| } else if (Optional<CallEnter> CE = PP.getAs<CallEnter>()) { |
| // If we reached the CallEnter for this function, it has no statements. |
| if (CE->getCalleeContext() == SF) |
| break; |
| } |
| |
| if (Node->pred_empty()) |
| return std::pair<const Stmt*, const CFGBlock*>((Stmt*)0, (CFGBlock*)0); |
| |
| Node = *Node->pred_begin(); |
| } |
| |
| return std::pair<const Stmt*, const CFGBlock*>(S, Blk); |
| } |
| |
| /// Adjusts a return value when the called function's return type does not |
| /// match the caller's expression type. This can happen when a dynamic call |
| /// is devirtualized, and the overridding method has a covariant (more specific) |
| /// return type than the parent's method. For C++ objects, this means we need |
| /// to add base casts. |
| static SVal adjustReturnValue(SVal V, QualType ExpectedTy, QualType ActualTy, |
| StoreManager &StoreMgr) { |
| // For now, the only adjustments we handle apply only to locations. |
| if (!V.getAs<Loc>()) |
| return V; |
| |
| // If the types already match, don't do any unnecessary work. |
| ExpectedTy = ExpectedTy.getCanonicalType(); |
| ActualTy = ActualTy.getCanonicalType(); |
| if (ExpectedTy == ActualTy) |
| return V; |
| |
| // No adjustment is needed between Objective-C pointer types. |
| if (ExpectedTy->isObjCObjectPointerType() && |
| ActualTy->isObjCObjectPointerType()) |
| return V; |
| |
| // C++ object pointers may need "derived-to-base" casts. |
| const CXXRecordDecl *ExpectedClass = ExpectedTy->getPointeeCXXRecordDecl(); |
| const CXXRecordDecl *ActualClass = ActualTy->getPointeeCXXRecordDecl(); |
| if (ExpectedClass && ActualClass) { |
| CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, |
| /*DetectVirtual=*/false); |
| if (ActualClass->isDerivedFrom(ExpectedClass, Paths) && |
| !Paths.isAmbiguous(ActualTy->getCanonicalTypeUnqualified())) { |
| return StoreMgr.evalDerivedToBase(V, Paths.front()); |
| } |
| } |
| |
| // Unfortunately, Objective-C does not enforce that overridden methods have |
| // covariant return types, so we can't assert that that never happens. |
| // Be safe and return UnknownVal(). |
| return UnknownVal(); |
| } |
| |
| void ExprEngine::removeDeadOnEndOfFunction(NodeBuilderContext& BC, |
| ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| // Find the last statement in the function and the corresponding basic block. |
| const Stmt *LastSt = 0; |
| const CFGBlock *Blk = 0; |
| std::tie(LastSt, Blk) = getLastStmt(Pred); |
| if (!Blk || !LastSt) { |
| Dst.Add(Pred); |
| return; |
| } |
| |
| // Here, we destroy the current location context. We use the current |
| // function's entire body as a diagnostic statement, with which the program |
| // point will be associated. However, we only want to use LastStmt as a |
| // reference for what to clean up if it's a ReturnStmt; otherwise, everything |
| // is dead. |
| SaveAndRestore<const NodeBuilderContext *> NodeContextRAII(currBldrCtx, &BC); |
| const LocationContext *LCtx = Pred->getLocationContext(); |
| removeDead(Pred, Dst, dyn_cast<ReturnStmt>(LastSt), LCtx, |
| LCtx->getAnalysisDeclContext()->getBody(), |
| ProgramPoint::PostStmtPurgeDeadSymbolsKind); |
| } |
| |
| static bool wasDifferentDeclUsedForInlining(CallEventRef<> Call, |
| const StackFrameContext *calleeCtx) { |
| const Decl *RuntimeCallee = calleeCtx->getDecl(); |
| const Decl *StaticDecl = Call->getDecl(); |
| assert(RuntimeCallee); |
| if (!StaticDecl) |
| return true; |
| return RuntimeCallee->getCanonicalDecl() != StaticDecl->getCanonicalDecl(); |
| } |
| |
| /// Returns true if the CXXConstructExpr \p E was intended to construct a |
| /// prvalue for the region in \p V. |
| /// |
| /// Note that we can't just test for rvalue vs. glvalue because |
| /// CXXConstructExprs embedded in DeclStmts and initializers are considered |
| /// rvalues by the AST, and the analyzer would like to treat them as lvalues. |
| static bool isTemporaryPRValue(const CXXConstructExpr *E, SVal V) { |
| if (E->isGLValue()) |
| return false; |
| |
| const MemRegion *MR = V.getAsRegion(); |
| if (!MR) |
| return false; |
| |
| return isa<CXXTempObjectRegion>(MR); |
| } |
| |
| /// The call exit is simulated with a sequence of nodes, which occur between |
| /// CallExitBegin and CallExitEnd. The following operations occur between the |
| /// two program points: |
| /// 1. CallExitBegin (triggers the start of call exit sequence) |
| /// 2. Bind the return value |
| /// 3. Run Remove dead bindings to clean up the dead symbols from the callee. |
| /// 4. CallExitEnd (switch to the caller context) |
| /// 5. PostStmt<CallExpr> |
| void ExprEngine::processCallExit(ExplodedNode *CEBNode) { |
| // Step 1 CEBNode was generated before the call. |
| PrettyStackTraceLocationContext CrashInfo(CEBNode->getLocationContext()); |
| const StackFrameContext *calleeCtx = |
| CEBNode->getLocationContext()->getCurrentStackFrame(); |
| |
| // The parent context might not be a stack frame, so make sure we |
| // look up the first enclosing stack frame. |
| const StackFrameContext *callerCtx = |
| calleeCtx->getParent()->getCurrentStackFrame(); |
| |
| const Stmt *CE = calleeCtx->getCallSite(); |
| ProgramStateRef state = CEBNode->getState(); |
| // Find the last statement in the function and the corresponding basic block. |
| const Stmt *LastSt = 0; |
| const CFGBlock *Blk = 0; |
| std::tie(LastSt, Blk) = getLastStmt(CEBNode); |
| |
| // Generate a CallEvent /before/ cleaning the state, so that we can get the |
| // correct value for 'this' (if necessary). |
| CallEventManager &CEMgr = getStateManager().getCallEventManager(); |
| CallEventRef<> Call = CEMgr.getCaller(calleeCtx, state); |
| |
| // Step 2: generate node with bound return value: CEBNode -> BindedRetNode. |
| |
| // If the callee returns an expression, bind its value to CallExpr. |
| if (CE) { |
| if (const ReturnStmt *RS = dyn_cast_or_null<ReturnStmt>(LastSt)) { |
| const LocationContext *LCtx = CEBNode->getLocationContext(); |
| SVal V = state->getSVal(RS, LCtx); |
| |
| // Ensure that the return type matches the type of the returned Expr. |
| if (wasDifferentDeclUsedForInlining(Call, calleeCtx)) { |
| QualType ReturnedTy = |
| CallEvent::getDeclaredResultType(calleeCtx->getDecl()); |
| if (!ReturnedTy.isNull()) { |
| if (const Expr *Ex = dyn_cast<Expr>(CE)) { |
| V = adjustReturnValue(V, Ex->getType(), ReturnedTy, |
| getStoreManager()); |
| } |
| } |
| } |
| |
| state = state->BindExpr(CE, callerCtx, V); |
| } |
| |
| // Bind the constructed object value to CXXConstructExpr. |
| if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(CE)) { |
| loc::MemRegionVal This = |
| svalBuilder.getCXXThis(CCE->getConstructor()->getParent(), calleeCtx); |
| SVal ThisV = state->getSVal(This); |
| |
| // If the constructed object is a temporary prvalue, get its bindings. |
| if (isTemporaryPRValue(CCE, ThisV)) |
| ThisV = state->getSVal(ThisV.castAs<Loc>()); |
| |
| state = state->BindExpr(CCE, callerCtx, ThisV); |
| } |
| } |
| |
| // Step 3: BindedRetNode -> CleanedNodes |
| // If we can find a statement and a block in the inlined function, run remove |
| // dead bindings before returning from the call. This is important to ensure |
| // that we report the issues such as leaks in the stack contexts in which |
| // they occurred. |
| ExplodedNodeSet CleanedNodes; |
| if (LastSt && Blk && AMgr.options.AnalysisPurgeOpt != PurgeNone) { |
| static SimpleProgramPointTag retValBind("ExprEngine", "Bind Return Value"); |
| PostStmt Loc(LastSt, calleeCtx, &retValBind); |
| bool isNew; |
| ExplodedNode *BindedRetNode = G.getNode(Loc, state, false, &isNew); |
| BindedRetNode->addPredecessor(CEBNode, G); |
| if (!isNew) |
| return; |
| |
| NodeBuilderContext Ctx(getCoreEngine(), Blk, BindedRetNode); |
| currBldrCtx = &Ctx; |
| // Here, we call the Symbol Reaper with 0 statement and callee location |
| // context, telling it to clean up everything in the callee's context |
| // (and its children). We use the callee's function body as a diagnostic |
| // statement, with which the program point will be associated. |
| removeDead(BindedRetNode, CleanedNodes, 0, calleeCtx, |
| calleeCtx->getAnalysisDeclContext()->getBody(), |
| ProgramPoint::PostStmtPurgeDeadSymbolsKind); |
| currBldrCtx = 0; |
| } else { |
| CleanedNodes.Add(CEBNode); |
| } |
| |
| for (ExplodedNodeSet::iterator I = CleanedNodes.begin(), |
| E = CleanedNodes.end(); I != E; ++I) { |
| |
| // Step 4: Generate the CallExit and leave the callee's context. |
| // CleanedNodes -> CEENode |
| CallExitEnd Loc(calleeCtx, callerCtx); |
| bool isNew; |
| ProgramStateRef CEEState = (*I == CEBNode) ? state : (*I)->getState(); |
| ExplodedNode *CEENode = G.getNode(Loc, CEEState, false, &isNew); |
| CEENode->addPredecessor(*I, G); |
| if (!isNew) |
| return; |
| |
| // Step 5: Perform the post-condition check of the CallExpr and enqueue the |
| // result onto the work list. |
| // CEENode -> Dst -> WorkList |
| NodeBuilderContext Ctx(Engine, calleeCtx->getCallSiteBlock(), CEENode); |
| SaveAndRestore<const NodeBuilderContext*> NBCSave(currBldrCtx, |
| &Ctx); |
| SaveAndRestore<unsigned> CBISave(currStmtIdx, calleeCtx->getIndex()); |
| |
| CallEventRef<> UpdatedCall = Call.cloneWithState(CEEState); |
| |
| ExplodedNodeSet DstPostCall; |
| getCheckerManager().runCheckersForPostCall(DstPostCall, CEENode, |
| *UpdatedCall, *this, |
| /*WasInlined=*/true); |
| |
| ExplodedNodeSet Dst; |
| if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(Call)) { |
| getCheckerManager().runCheckersForPostObjCMessage(Dst, DstPostCall, *Msg, |
| *this, |
| /*WasInlined=*/true); |
| } else if (CE) { |
| getCheckerManager().runCheckersForPostStmt(Dst, DstPostCall, CE, |
| *this, /*WasInlined=*/true); |
| } else { |
| Dst.insert(DstPostCall); |
| } |
| |
| // Enqueue the next element in the block. |
| for (ExplodedNodeSet::iterator PSI = Dst.begin(), PSE = Dst.end(); |
| PSI != PSE; ++PSI) { |
| Engine.getWorkList()->enqueue(*PSI, calleeCtx->getCallSiteBlock(), |
| calleeCtx->getIndex()+1); |
| } |
| } |
| } |
| |
| void ExprEngine::examineStackFrames(const Decl *D, const LocationContext *LCtx, |
| bool &IsRecursive, unsigned &StackDepth) { |
| IsRecursive = false; |
| StackDepth = 0; |
| |
| while (LCtx) { |
| if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LCtx)) { |
| const Decl *DI = SFC->getDecl(); |
| |
| // Mark recursive (and mutually recursive) functions and always count |
| // them when measuring the stack depth. |
| if (DI == D) { |
| IsRecursive = true; |
| ++StackDepth; |
| LCtx = LCtx->getParent(); |
| continue; |
| } |
| |
| // Do not count the small functions when determining the stack depth. |
| AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(DI); |
| const CFG *CalleeCFG = CalleeADC->getCFG(); |
| if (CalleeCFG->getNumBlockIDs() > AMgr.options.getAlwaysInlineSize()) |
| ++StackDepth; |
| } |
| LCtx = LCtx->getParent(); |
| } |
| |
| } |
| |
| static bool IsInStdNamespace(const FunctionDecl *FD) { |
| const DeclContext *DC = FD->getEnclosingNamespaceContext(); |
| const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(DC); |
| if (!ND) |
| return false; |
| |
| while (const DeclContext *Parent = ND->getParent()) { |
| if (!isa<NamespaceDecl>(Parent)) |
| break; |
| ND = cast<NamespaceDecl>(Parent); |
| } |
| |
| return ND->getName() == "std"; |
| } |
| |
| // The GDM component containing the dynamic dispatch bifurcation info. When |
| // the exact type of the receiver is not known, we want to explore both paths - |
| // one on which we do inline it and the other one on which we don't. This is |
| // done to ensure we do not drop coverage. |
| // This is the map from the receiver region to a bool, specifying either we |
| // consider this region's information precise or not along the given path. |
| namespace { |
| enum DynamicDispatchMode { |
| DynamicDispatchModeInlined = 1, |
| DynamicDispatchModeConservative |
| }; |
| } |
| REGISTER_TRAIT_WITH_PROGRAMSTATE(DynamicDispatchBifurcationMap, |
| CLANG_ENTO_PROGRAMSTATE_MAP(const MemRegion *, |
| unsigned)) |
| |
| bool ExprEngine::inlineCall(const CallEvent &Call, const Decl *D, |
| NodeBuilder &Bldr, ExplodedNode *Pred, |
| ProgramStateRef State) { |
| assert(D); |
| |
| const LocationContext *CurLC = Pred->getLocationContext(); |
| const StackFrameContext *CallerSFC = CurLC->getCurrentStackFrame(); |
| const LocationContext *ParentOfCallee = CallerSFC; |
| if (Call.getKind() == CE_Block) { |
| const BlockDataRegion *BR = cast<BlockCall>(Call).getBlockRegion(); |
| assert(BR && "If we have the block definition we should have its region"); |
| AnalysisDeclContext *BlockCtx = AMgr.getAnalysisDeclContext(D); |
| ParentOfCallee = BlockCtx->getBlockInvocationContext(CallerSFC, |
| cast<BlockDecl>(D), |
| BR); |
| } |
| |
| // This may be NULL, but that's fine. |
| const Expr *CallE = Call.getOriginExpr(); |
| |
| // Construct a new stack frame for the callee. |
| AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(D); |
| const StackFrameContext *CalleeSFC = |
| CalleeADC->getStackFrame(ParentOfCallee, CallE, |
| currBldrCtx->getBlock(), |
| currStmtIdx); |
| |
| |
| CallEnter Loc(CallE, CalleeSFC, CurLC); |
| |
| // Construct a new state which contains the mapping from actual to |
| // formal arguments. |
| State = State->enterStackFrame(Call, CalleeSFC); |
| |
| bool isNew; |
| if (ExplodedNode *N = G.getNode(Loc, State, false, &isNew)) { |
| N->addPredecessor(Pred, G); |
| if (isNew) |
| Engine.getWorkList()->enqueue(N); |
| } |
| |
| // If we decided to inline the call, the successor has been manually |
| // added onto the work list so remove it from the node builder. |
| Bldr.takeNodes(Pred); |
| |
| NumInlinedCalls++; |
| |
| // Mark the decl as visited. |
| if (VisitedCallees) |
| VisitedCallees->insert(D); |
| |
| return true; |
| } |
| |
| static ProgramStateRef getInlineFailedState(ProgramStateRef State, |
| const Stmt *CallE) { |
| const void *ReplayState = State->get<ReplayWithoutInlining>(); |
| if (!ReplayState) |
| return 0; |
| |
| assert(ReplayState == CallE && "Backtracked to the wrong call."); |
| (void)CallE; |
| |
| return State->remove<ReplayWithoutInlining>(); |
| } |
| |
| void ExprEngine::VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred, |
| ExplodedNodeSet &dst) { |
| // Perform the previsit of the CallExpr. |
| ExplodedNodeSet dstPreVisit; |
| getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, CE, *this); |
| |
| // Get the call in its initial state. We use this as a template to perform |
| // all the checks. |
| CallEventManager &CEMgr = getStateManager().getCallEventManager(); |
| CallEventRef<> CallTemplate |
| = CEMgr.getSimpleCall(CE, Pred->getState(), Pred->getLocationContext()); |
| |
| // Evaluate the function call. We try each of the checkers |
| // to see if the can evaluate the function call. |
| ExplodedNodeSet dstCallEvaluated; |
| for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end(); |
| I != E; ++I) { |
| evalCall(dstCallEvaluated, *I, *CallTemplate); |
| } |
| |
| // Finally, perform the post-condition check of the CallExpr and store |
| // the created nodes in 'Dst'. |
| // Note that if the call was inlined, dstCallEvaluated will be empty. |
| // The post-CallExpr check will occur in processCallExit. |
| getCheckerManager().runCheckersForPostStmt(dst, dstCallEvaluated, CE, |
| *this); |
| } |
| |
| void ExprEngine::evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred, |
| const CallEvent &Call) { |
| // WARNING: At this time, the state attached to 'Call' may be older than the |
| // state in 'Pred'. This is a minor optimization since CheckerManager will |
| // use an updated CallEvent instance when calling checkers, but if 'Call' is |
| // ever used directly in this function all callers should be updated to pass |
| // the most recent state. (It is probably not worth doing the work here since |
| // for some callers this will not be necessary.) |
| |
| // Run any pre-call checks using the generic call interface. |
| ExplodedNodeSet dstPreVisit; |
| getCheckerManager().runCheckersForPreCall(dstPreVisit, Pred, Call, *this); |
| |
| // Actually evaluate the function call. We try each of the checkers |
| // to see if the can evaluate the function call, and get a callback at |
| // defaultEvalCall if all of them fail. |
| ExplodedNodeSet dstCallEvaluated; |
| getCheckerManager().runCheckersForEvalCall(dstCallEvaluated, dstPreVisit, |
| Call, *this); |
| |
| // Finally, run any post-call checks. |
| getCheckerManager().runCheckersForPostCall(Dst, dstCallEvaluated, |
| Call, *this); |
| } |
| |
| ProgramStateRef ExprEngine::bindReturnValue(const CallEvent &Call, |
| const LocationContext *LCtx, |
| ProgramStateRef State) { |
| const Expr *E = Call.getOriginExpr(); |
| if (!E) |
| return State; |
| |
| // Some method families have known return values. |
| if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(&Call)) { |
| switch (Msg->getMethodFamily()) { |
| default: |
| break; |
| case OMF_autorelease: |
| case OMF_retain: |
| case OMF_self: { |
| // These methods return their receivers. |
| return State->BindExpr(E, LCtx, Msg->getReceiverSVal()); |
| } |
| } |
| } else if (const CXXConstructorCall *C = dyn_cast<CXXConstructorCall>(&Call)){ |
| SVal ThisV = C->getCXXThisVal(); |
| |
| // If the constructed object is a temporary prvalue, get its bindings. |
| if (isTemporaryPRValue(cast<CXXConstructExpr>(E), ThisV)) |
| ThisV = State->getSVal(ThisV.castAs<Loc>()); |
| |
| return State->BindExpr(E, LCtx, ThisV); |
| } |
| |
| // Conjure a symbol if the return value is unknown. |
| QualType ResultTy = Call.getResultType(); |
| SValBuilder &SVB = getSValBuilder(); |
| unsigned Count = currBldrCtx->blockCount(); |
| SVal R = SVB.conjureSymbolVal(0, E, LCtx, ResultTy, Count); |
| return State->BindExpr(E, LCtx, R); |
| } |
| |
| // Conservatively evaluate call by invalidating regions and binding |
| // a conjured return value. |
| void ExprEngine::conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr, |
| ExplodedNode *Pred, |
| ProgramStateRef State) { |
| State = Call.invalidateRegions(currBldrCtx->blockCount(), State); |
| State = bindReturnValue(Call, Pred->getLocationContext(), State); |
| |
| // And make the result node. |
| Bldr.generateNode(Call.getProgramPoint(), State, Pred); |
| } |
| |
| enum CallInlinePolicy { |
| CIP_Allowed, |
| CIP_DisallowedOnce, |
| CIP_DisallowedAlways |
| }; |
| |
| static CallInlinePolicy mayInlineCallKind(const CallEvent &Call, |
| const ExplodedNode *Pred, |
| AnalyzerOptions &Opts) { |
| const LocationContext *CurLC = Pred->getLocationContext(); |
| const StackFrameContext *CallerSFC = CurLC->getCurrentStackFrame(); |
| switch (Call.getKind()) { |
| case CE_Function: |
| case CE_Block: |
| break; |
| case CE_CXXMember: |
| case CE_CXXMemberOperator: |
| if (!Opts.mayInlineCXXMemberFunction(CIMK_MemberFunctions)) |
| return CIP_DisallowedAlways; |
| break; |
| case CE_CXXConstructor: { |
| if (!Opts.mayInlineCXXMemberFunction(CIMK_Constructors)) |
| return CIP_DisallowedAlways; |
| |
| const CXXConstructorCall &Ctor = cast<CXXConstructorCall>(Call); |
| |
| // FIXME: We don't handle constructors or destructors for arrays properly. |
| // Even once we do, we still need to be careful about implicitly-generated |
| // initializers for array fields in default move/copy constructors. |
| const MemRegion *Target = Ctor.getCXXThisVal().getAsRegion(); |
| if (Target && isa<ElementRegion>(Target)) |
| return CIP_DisallowedOnce; |
| |
| // FIXME: This is a hack. We don't use the correct region for a new |
| // expression, so if we inline the constructor its result will just be |
| // thrown away. This short-term hack is tracked in <rdar://problem/12180598> |
| // and the longer-term possible fix is discussed in PR12014. |
| const CXXConstructExpr *CtorExpr = Ctor.getOriginExpr(); |
| if (const Stmt *Parent = CurLC->getParentMap().getParent(CtorExpr)) |
| if (isa<CXXNewExpr>(Parent)) |
| return CIP_DisallowedOnce; |
| |
| // Inlining constructors requires including initializers in the CFG. |
| const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); |
| assert(ADC->getCFGBuildOptions().AddInitializers && "No CFG initializers"); |
| (void)ADC; |
| |
| // If the destructor is trivial, it's always safe to inline the constructor. |
| if (Ctor.getDecl()->getParent()->hasTrivialDestructor()) |
| break; |
| |
| // For other types, only inline constructors if destructor inlining is |
| // also enabled. |
| if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) |
| return CIP_DisallowedAlways; |
| |
| // FIXME: This is a hack. We don't handle temporary destructors |
| // right now, so we shouldn't inline their constructors. |
| if (CtorExpr->getConstructionKind() == CXXConstructExpr::CK_Complete) |
| if (!Target || !isa<DeclRegion>(Target)) |
| return CIP_DisallowedOnce; |
| |
| break; |
| } |
| case CE_CXXDestructor: { |
| if (!Opts.mayInlineCXXMemberFunction(CIMK_Destructors)) |
| return CIP_DisallowedAlways; |
| |
| // Inlining destructors requires building the CFG correctly. |
| const AnalysisDeclContext *ADC = CallerSFC->getAnalysisDeclContext(); |
| assert(ADC->getCFGBuildOptions().AddImplicitDtors && "No CFG destructors"); |
| (void)ADC; |
| |
| const CXXDestructorCall &Dtor = cast<CXXDestructorCall>(Call); |
| |
| // FIXME: We don't handle constructors or destructors for arrays properly. |
| const MemRegion *Target = Dtor.getCXXThisVal().getAsRegion(); |
| if (Target && isa<ElementRegion>(Target)) |
| return CIP_DisallowedOnce; |
| |
| break; |
| } |
| case CE_CXXAllocator: |
| if (Opts.mayInlineCXXAllocator()) |
| break; |
| // Do not inline allocators until we model deallocators. |
| // This is unfortunate, but basically necessary for smart pointers and such. |
| return CIP_DisallowedAlways; |
| case CE_ObjCMessage: |
| if (!Opts.mayInlineObjCMethod()) |
| return CIP_DisallowedAlways; |
| if (!(Opts.getIPAMode() == IPAK_DynamicDispatch || |
| Opts.getIPAMode() == IPAK_DynamicDispatchBifurcate)) |
| return CIP_DisallowedAlways; |
| break; |
| } |
| |
| return CIP_Allowed; |
| } |
| |
| /// Returns true if the given C++ class contains a member with the given name. |
| static bool hasMember(const ASTContext &Ctx, const CXXRecordDecl *RD, |
| StringRef Name) { |
| const IdentifierInfo &II = Ctx.Idents.get(Name); |
| DeclarationName DeclName = Ctx.DeclarationNames.getIdentifier(&II); |
| if (!RD->lookup(DeclName).empty()) |
| return true; |
| |
| CXXBasePaths Paths(false, false, false); |
| if (RD->lookupInBases(&CXXRecordDecl::FindOrdinaryMember, |
| DeclName.getAsOpaquePtr(), |
| Paths)) |
| return true; |
| |
| return false; |
| } |
| |
| /// Returns true if the given C++ class is a container or iterator. |
| /// |
| /// Our heuristic for this is whether it contains a method named 'begin()' or a |
| /// nested type named 'iterator' or 'iterator_category'. |
| static bool isContainerClass(const ASTContext &Ctx, const CXXRecordDecl *RD) { |
| return hasMember(Ctx, RD, "begin") || |
| hasMember(Ctx, RD, "iterator") || |
| hasMember(Ctx, RD, "iterator_category"); |
| } |
| |
| /// Returns true if the given function refers to a constructor or destructor of |
| /// a C++ container or iterator. |
| /// |
| /// We generally do a poor job modeling most containers right now, and would |
| /// prefer not to inline their setup and teardown. |
| static bool isContainerCtorOrDtor(const ASTContext &Ctx, |
| const FunctionDecl *FD) { |
| if (!(isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))) |
| return false; |
| |
| const CXXRecordDecl *RD = cast<CXXMethodDecl>(FD)->getParent(); |
| return isContainerClass(Ctx, RD); |
| } |
| |
| /// Returns true if the given function is the destructor of a class named |
| /// "shared_ptr". |
| static bool isCXXSharedPtrDtor(const FunctionDecl *FD) { |
| const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(FD); |
| if (!Dtor) |
| return false; |
| |
| const CXXRecordDecl *RD = Dtor->getParent(); |
| if (const IdentifierInfo *II = RD->getDeclName().getAsIdentifierInfo()) |
| if (II->isStr("shared_ptr")) |
| return true; |
| |
| return false; |
| } |
| |
| /// Returns true if the function in \p CalleeADC may be inlined in general. |
| /// |
| /// This checks static properties of the function, such as its signature and |
| /// CFG, to determine whether the analyzer should ever consider inlining it, |
| /// in any context. |
| static bool mayInlineDecl(AnalysisDeclContext *CalleeADC, |
| AnalyzerOptions &Opts) { |
| // FIXME: Do not inline variadic calls. |
| if (CallEvent::isVariadic(CalleeADC->getDecl())) |
| return false; |
| |
| // Check certain C++-related inlining policies. |
| ASTContext &Ctx = CalleeADC->getASTContext(); |
| if (Ctx.getLangOpts().CPlusPlus) { |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeADC->getDecl())) { |
| // Conditionally control the inlining of template functions. |
| if (!Opts.mayInlineTemplateFunctions()) |
| if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate) |
| return false; |
| |
| // Conditionally control the inlining of C++ standard library functions. |
| if (!Opts.mayInlineCXXStandardLibrary()) |
| if (Ctx.getSourceManager().isInSystemHeader(FD->getLocation())) |
| if (IsInStdNamespace(FD)) |
| return false; |
| |
| // Conditionally control the inlining of methods on objects that look |
| // like C++ containers. |
| if (!Opts.mayInlineCXXContainerCtorsAndDtors()) |
| if (!Ctx.getSourceManager().isInMainFile(FD->getLocation())) |
| if (isContainerCtorOrDtor(Ctx, FD)) |
| return false; |
| |
| // Conditionally control the inlining of the destructor of C++ shared_ptr. |
| // We don't currently do a good job modeling shared_ptr because we can't |
| // see the reference count, so treating as opaque is probably the best |
| // idea. |
| if (!Opts.mayInlineCXXSharedPtrDtor()) |
| if (isCXXSharedPtrDtor(FD)) |
| return false; |
| |
| } |
| } |
| |
| // It is possible that the CFG cannot be constructed. |
| // Be safe, and check if the CalleeCFG is valid. |
| const CFG *CalleeCFG = CalleeADC->getCFG(); |
| if (!CalleeCFG) |
| return false; |
| |
| // Do not inline large functions. |
| if (CalleeCFG->getNumBlockIDs() > Opts.getMaxInlinableSize()) |
| return false; |
| |
| // It is possible that the live variables analysis cannot be |
| // run. If so, bail out. |
| if (!CalleeADC->getAnalysis<RelaxedLiveVariables>()) |
| return false; |
| |
| return true; |
| } |
| |
| bool ExprEngine::shouldInlineCall(const CallEvent &Call, const Decl *D, |
| const ExplodedNode *Pred) { |
| if (!D) |
| return false; |
| |
| AnalysisManager &AMgr = getAnalysisManager(); |
| AnalyzerOptions &Opts = AMgr.options; |
| AnalysisDeclContextManager &ADCMgr = AMgr.getAnalysisDeclContextManager(); |
| AnalysisDeclContext *CalleeADC = ADCMgr.getContext(D); |
| |
| // Temporary object destructor processing is currently broken, so we never |
| // inline them. |
| // FIXME: Remove this once temp destructors are working. |
| if (isa<CXXDestructorCall>(Call)) { |
| if ((*currBldrCtx->getBlock())[currStmtIdx].getAs<CFGTemporaryDtor>()) |
| return false; |
| } |
| |
| // The auto-synthesized bodies are essential to inline as they are |
| // usually small and commonly used. Note: we should do this check early on to |
| // ensure we always inline these calls. |
| if (CalleeADC->isBodyAutosynthesized()) |
| return true; |
| |
| if (!AMgr.shouldInlineCall()) |
| return false; |
| |
| // Check if this function has been marked as non-inlinable. |
| Optional<bool> MayInline = Engine.FunctionSummaries->mayInline(D); |
| if (MayInline.hasValue()) { |
| if (!MayInline.getValue()) |
| return false; |
| |
| } else { |
| // We haven't actually checked the static properties of this function yet. |
| // Do that now, and record our decision in the function summaries. |
| if (mayInlineDecl(CalleeADC, Opts)) { |
| Engine.FunctionSummaries->markMayInline(D); |
| } else { |
| Engine.FunctionSummaries->markShouldNotInline(D); |
| return false; |
| } |
| } |
| |
| // Check if we should inline a call based on its kind. |
| // FIXME: this checks both static and dynamic properties of the call, which |
| // means we're redoing a bit of work that could be cached in the function |
| // summary. |
| CallInlinePolicy CIP = mayInlineCallKind(Call, Pred, Opts); |
| if (CIP != CIP_Allowed) { |
| if (CIP == CIP_DisallowedAlways) { |
| assert(!MayInline.hasValue() || MayInline.getValue()); |
| Engine.FunctionSummaries->markShouldNotInline(D); |
| } |
| return false; |
| } |
| |
| const CFG *CalleeCFG = CalleeADC->getCFG(); |
| |
| // Do not inline if recursive or we've reached max stack frame count. |
| bool IsRecursive = false; |
| unsigned StackDepth = 0; |
| examineStackFrames(D, Pred->getLocationContext(), IsRecursive, StackDepth); |
| if ((StackDepth >= Opts.InlineMaxStackDepth) && |
| ((CalleeCFG->getNumBlockIDs() > Opts.getAlwaysInlineSize()) |
| || IsRecursive)) |
| return false; |
| |
| // Do not inline large functions too many times. |
| if ((Engine.FunctionSummaries->getNumTimesInlined(D) > |
| Opts.getMaxTimesInlineLarge()) && |
| CalleeCFG->getNumBlockIDs() > 13) { |
| NumReachedInlineCountMax++; |
| return false; |
| } |
| |
| if (HowToInline == Inline_Minimal && |
| (CalleeCFG->getNumBlockIDs() > Opts.getAlwaysInlineSize() |
| || IsRecursive)) |
| return false; |
| |
| Engine.FunctionSummaries->bumpNumTimesInlined(D); |
| |
| return true; |
| } |
| |
| static bool isTrivialObjectAssignment(const CallEvent &Call) { |
| const CXXInstanceCall *ICall = dyn_cast<CXXInstanceCall>(&Call); |
| if (!ICall) |
| return false; |
| |
| const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(ICall->getDecl()); |
| if (!MD) |
| return false; |
| if (!(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())) |
| return false; |
| |
| return MD->isTrivial(); |
| } |
| |
| void ExprEngine::defaultEvalCall(NodeBuilder &Bldr, ExplodedNode *Pred, |
| const CallEvent &CallTemplate) { |
| // Make sure we have the most recent state attached to the call. |
| ProgramStateRef State = Pred->getState(); |
| CallEventRef<> Call = CallTemplate.cloneWithState(State); |
| |
| // Special-case trivial assignment operators. |
| if (isTrivialObjectAssignment(*Call)) { |
| performTrivialCopy(Bldr, Pred, *Call); |
| return; |
| } |
| |
| // Try to inline the call. |
| // The origin expression here is just used as a kind of checksum; |
| // this should still be safe even for CallEvents that don't come from exprs. |
| const Expr *E = Call->getOriginExpr(); |
| |
| ProgramStateRef InlinedFailedState = getInlineFailedState(State, E); |
| if (InlinedFailedState) { |
| // If we already tried once and failed, make sure we don't retry later. |
| State = InlinedFailedState; |
| } else { |
| RuntimeDefinition RD = Call->getRuntimeDefinition(); |
| const Decl *D = RD.getDecl(); |
| if (shouldInlineCall(*Call, D, Pred)) { |
| if (RD.mayHaveOtherDefinitions()) { |
| AnalyzerOptions &Options = getAnalysisManager().options; |
| |
| // Explore with and without inlining the call. |
| if (Options.getIPAMode() == IPAK_DynamicDispatchBifurcate) { |
| BifurcateCall(RD.getDispatchRegion(), *Call, D, Bldr, Pred); |
| return; |
| } |
| |
| // Don't inline if we're not in any dynamic dispatch mode. |
| if (Options.getIPAMode() != IPAK_DynamicDispatch) { |
| conservativeEvalCall(*Call, Bldr, Pred, State); |
| return; |
| } |
| } |
| |
| // We are not bifurcating and we do have a Decl, so just inline. |
| if (inlineCall(*Call, D, Bldr, Pred, State)) |
| return; |
| } |
| } |
| |
| // If we can't inline it, handle the return value and invalidate the regions. |
| conservativeEvalCall(*Call, Bldr, Pred, State); |
| } |
| |
| void ExprEngine::BifurcateCall(const MemRegion *BifurReg, |
| const CallEvent &Call, const Decl *D, |
| NodeBuilder &Bldr, ExplodedNode *Pred) { |
| assert(BifurReg); |
| BifurReg = BifurReg->StripCasts(); |
| |
| // Check if we've performed the split already - note, we only want |
| // to split the path once per memory region. |
| ProgramStateRef State = Pred->getState(); |
| const unsigned *BState = |
| State->get<DynamicDispatchBifurcationMap>(BifurReg); |
| if (BState) { |
| // If we are on "inline path", keep inlining if possible. |
| if (*BState == DynamicDispatchModeInlined) |
| if (inlineCall(Call, D, Bldr, Pred, State)) |
| return; |
| // If inline failed, or we are on the path where we assume we |
| // don't have enough info about the receiver to inline, conjure the |
| // return value and invalidate the regions. |
| conservativeEvalCall(Call, Bldr, Pred, State); |
| return; |
| } |
| |
| // If we got here, this is the first time we process a message to this |
| // region, so split the path. |
| ProgramStateRef IState = |
| State->set<DynamicDispatchBifurcationMap>(BifurReg, |
| DynamicDispatchModeInlined); |
| inlineCall(Call, D, Bldr, Pred, IState); |
| |
| ProgramStateRef NoIState = |
| State->set<DynamicDispatchBifurcationMap>(BifurReg, |
| DynamicDispatchModeConservative); |
| conservativeEvalCall(Call, Bldr, Pred, NoIState); |
| |
| NumOfDynamicDispatchPathSplits++; |
| return; |
| } |
| |
| |
| void ExprEngine::VisitReturnStmt(const ReturnStmt *RS, ExplodedNode *Pred, |
| ExplodedNodeSet &Dst) { |
| |
| ExplodedNodeSet dstPreVisit; |
| getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, RS, *this); |
| |
| StmtNodeBuilder B(dstPreVisit, Dst, *currBldrCtx); |
| |
| if (RS->getRetValue()) { |
| for (ExplodedNodeSet::iterator it = dstPreVisit.begin(), |
| ei = dstPreVisit.end(); it != ei; ++it) { |
| B.generateNode(RS, *it, (*it)->getState()); |
| } |
| } |
| } |