//===-- ExprEngine.h - Path-Sensitive Expression-Level Dataflow ---*- 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 a meta-engine for path-sensitive dataflow analysis that // is built on CoreEngine, but provides the boilerplate to execute transfer // functions and build the ExplodedGraph at the expression level. // //===----------------------------------------------------------------------===// #ifndef LLVM_CLANG_GR_EXPRENGINE #define LLVM_CLANG_GR_EXPRENGINE #include "clang/AST/Expr.h" #include "clang/AST/Type.h" #include "clang/Analysis/DomainSpecific/ObjCNoReturn.h" #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h" #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h" #include "clang/StaticAnalyzer/Core/PathSensitive/CoreEngine.h" #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" #include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h" namespace clang { class AnalysisDeclContextManager; class CXXCatchStmt; class CXXConstructExpr; class CXXDeleteExpr; class CXXNewExpr; class CXXTemporaryObjectExpr; class CXXThisExpr; class MaterializeTemporaryExpr; class ObjCAtSynchronizedStmt; class ObjCForCollectionStmt; namespace ento { class AnalysisManager; class CallEvent; class SimpleCall; class CXXConstructorCall; class ExprEngine : public SubEngine { public: /// The modes of inlining, which override the default analysis-wide settings. enum InliningModes { /// Follow the default settings for inlining callees. Inline_Regular = 0, /// Do minimal inlining of callees. Inline_Minimal = 0x1 }; private: AnalysisManager &AMgr; AnalysisDeclContextManager &AnalysisDeclContexts; CoreEngine Engine; /// G - the simulation graph. ExplodedGraph& G; /// StateMgr - Object that manages the data for all created states. ProgramStateManager StateMgr; /// SymMgr - Object that manages the symbol information. SymbolManager& SymMgr; /// svalBuilder - SValBuilder object that creates SVals from expressions. SValBuilder &svalBuilder; unsigned int currStmtIdx; const NodeBuilderContext *currBldrCtx; /// Helper object to determine if an Objective-C message expression /// implicitly never returns. ObjCNoReturn ObjCNoRet; /// Whether or not GC is enabled in this analysis. bool ObjCGCEnabled; /// The BugReporter associated with this engine. It is important that /// this object be placed at the very end of member variables so that its /// destructor is called before the rest of the ExprEngine is destroyed. GRBugReporter BR; /// The functions which have been analyzed through inlining. This is owned by /// AnalysisConsumer. It can be null. SetOfConstDecls *VisitedCallees; /// The flag, which specifies the mode of inlining for the engine. InliningModes HowToInline; public: ExprEngine(AnalysisManager &mgr, bool gcEnabled, SetOfConstDecls *VisitedCalleesIn, FunctionSummariesTy *FS, InliningModes HowToInlineIn); ~ExprEngine(); /// Returns true if there is still simulation state on the worklist. bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) { return Engine.ExecuteWorkList(L, Steps, 0); } /// Execute the work list with an initial state. Nodes that reaches the exit /// of the function are added into the Dst set, which represent the exit /// state of the function call. Returns true if there is still simulation /// state on the worklist. bool ExecuteWorkListWithInitialState(const LocationContext *L, unsigned Steps, ProgramStateRef InitState, ExplodedNodeSet &Dst) { return Engine.ExecuteWorkListWithInitialState(L, Steps, InitState, Dst); } /// getContext - Return the ASTContext associated with this analysis. ASTContext &getContext() const { return AMgr.getASTContext(); } virtual AnalysisManager &getAnalysisManager() { return AMgr; } CheckerManager &getCheckerManager() const { return *AMgr.getCheckerManager(); } SValBuilder &getSValBuilder() { return svalBuilder; } BugReporter& getBugReporter() { return BR; } const NodeBuilderContext &getBuilderContext() { assert(currBldrCtx); return *currBldrCtx; } bool isObjCGCEnabled() { return ObjCGCEnabled; } const Stmt *getStmt() const; void GenerateAutoTransition(ExplodedNode *N); void enqueueEndOfPath(ExplodedNodeSet &S); void GenerateCallExitNode(ExplodedNode *N); /// Visualize the ExplodedGraph created by executing the simulation. void ViewGraph(bool trim = false); /// Visualize a trimmed ExplodedGraph that only contains paths to the given /// nodes. void ViewGraph(ArrayRef Nodes); /// getInitialState - Return the initial state used for the root vertex /// in the ExplodedGraph. ProgramStateRef getInitialState(const LocationContext *InitLoc); ExplodedGraph& getGraph() { return G; } const ExplodedGraph& getGraph() const { return G; } /// \brief Run the analyzer's garbage collection - remove dead symbols and /// bindings from the state. /// /// Checkers can participate in this process with two callbacks: /// \c checkLiveSymbols and \c checkDeadSymbols. See the CheckerDocumentation /// class for more information. /// /// \param Node The predecessor node, from which the processing should start. /// \param Out The returned set of output nodes. /// \param ReferenceStmt The statement which is about to be processed. /// Everything needed for this statement should be considered live. /// A null statement means that everything in child LocationContexts /// is dead. /// \param LC The location context of the \p ReferenceStmt. A null location /// context means that we have reached the end of analysis and that /// all statements and local variables should be considered dead. /// \param DiagnosticStmt Used as a location for any warnings that should /// occur while removing the dead (e.g. leaks). By default, the /// \p ReferenceStmt is used. /// \param K Denotes whether this is a pre- or post-statement purge. This /// must only be ProgramPoint::PostStmtPurgeDeadSymbolsKind if an /// entire location context is being cleared, in which case the /// \p ReferenceStmt must either be a ReturnStmt or \c NULL. Otherwise, /// it must be ProgramPoint::PreStmtPurgeDeadSymbolsKind (the default) /// and \p ReferenceStmt must be valid (non-null). void removeDead(ExplodedNode *Node, ExplodedNodeSet &Out, const Stmt *ReferenceStmt, const LocationContext *LC, const Stmt *DiagnosticStmt = 0, ProgramPoint::Kind K = ProgramPoint::PreStmtPurgeDeadSymbolsKind); /// processCFGElement - Called by CoreEngine. Used to generate new successor /// nodes by processing the 'effects' of a CFG element. void processCFGElement(const CFGElement E, ExplodedNode *Pred, unsigned StmtIdx, NodeBuilderContext *Ctx); void ProcessStmt(const CFGStmt S, ExplodedNode *Pred); void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred); void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred); void ProcessAutomaticObjDtor(const CFGAutomaticObjDtor D, ExplodedNode *Pred, ExplodedNodeSet &Dst); void ProcessDeleteDtor(const CFGDeleteDtor D, ExplodedNode *Pred, ExplodedNodeSet &Dst); void ProcessBaseDtor(const CFGBaseDtor D, ExplodedNode *Pred, ExplodedNodeSet &Dst); void ProcessMemberDtor(const CFGMemberDtor D, ExplodedNode *Pred, ExplodedNodeSet &Dst); void ProcessTemporaryDtor(const CFGTemporaryDtor D, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Called by CoreEngine when processing the entrance of a CFGBlock. virtual void processCFGBlockEntrance(const BlockEdge &L, NodeBuilderWithSinks &nodeBuilder, ExplodedNode *Pred); /// ProcessBranch - Called by CoreEngine. Used to generate successor /// nodes by processing the 'effects' of a branch condition. void processBranch(const Stmt *Condition, const Stmt *Term, NodeBuilderContext& BuilderCtx, ExplodedNode *Pred, ExplodedNodeSet &Dst, const CFGBlock *DstT, const CFGBlock *DstF); /// Called by CoreEngine. Used to processing branching behavior /// at static initalizers. void processStaticInitializer(const DeclStmt *DS, NodeBuilderContext& BuilderCtx, ExplodedNode *Pred, ExplodedNodeSet &Dst, const CFGBlock *DstT, const CFGBlock *DstF); /// processIndirectGoto - Called by CoreEngine. Used to generate successor /// nodes by processing the 'effects' of a computed goto jump. void processIndirectGoto(IndirectGotoNodeBuilder& builder); /// ProcessSwitch - Called by CoreEngine. Used to generate successor /// nodes by processing the 'effects' of a switch statement. void processSwitch(SwitchNodeBuilder& builder); /// Called by CoreEngine. Used to generate end-of-path /// nodes when the control reaches the end of a function. void processEndOfFunction(NodeBuilderContext& BC, ExplodedNode *Pred); /// Remove dead bindings/symbols before exiting a function. void removeDeadOnEndOfFunction(NodeBuilderContext& BC, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Generate the entry node of the callee. void processCallEnter(CallEnter CE, ExplodedNode *Pred); /// Generate the sequence of nodes that simulate the call exit and the post /// visit for CallExpr. void processCallExit(ExplodedNode *Pred); /// Called by CoreEngine when the analysis worklist has terminated. void processEndWorklist(bool hasWorkRemaining); /// evalAssume - Callback function invoked by the ConstraintManager when /// making assumptions about state values. ProgramStateRef processAssume(ProgramStateRef state, SVal cond,bool assumption); /// wantsRegionChangeUpdate - Called by ProgramStateManager to determine if a /// region change should trigger a processRegionChanges update. bool wantsRegionChangeUpdate(ProgramStateRef state); /// processRegionChanges - Called by ProgramStateManager whenever a change is made /// to the store. Used to update checkers that track region values. ProgramStateRef processRegionChanges(ProgramStateRef state, const InvalidatedSymbols *invalidated, ArrayRef ExplicitRegions, ArrayRef Regions, const CallEvent *Call); /// printState - Called by ProgramStateManager to print checker-specific data. void printState(raw_ostream &Out, ProgramStateRef State, const char *NL, const char *Sep); virtual ProgramStateManager& getStateManager() { return StateMgr; } StoreManager& getStoreManager() { return StateMgr.getStoreManager(); } ConstraintManager& getConstraintManager() { return StateMgr.getConstraintManager(); } // FIXME: Remove when we migrate over to just using SValBuilder. BasicValueFactory& getBasicVals() { return StateMgr.getBasicVals(); } // FIXME: Remove when we migrate over to just using ValueManager. SymbolManager& getSymbolManager() { return SymMgr; } const SymbolManager& getSymbolManager() const { return SymMgr; } // Functions for external checking of whether we have unfinished work bool wasBlocksExhausted() const { return Engine.wasBlocksExhausted(); } bool hasEmptyWorkList() const { return !Engine.getWorkList()->hasWork(); } bool hasWorkRemaining() const { return Engine.hasWorkRemaining(); } const CoreEngine &getCoreEngine() const { return Engine; } public: /// Visit - Transfer function logic for all statements. Dispatches to /// other functions that handle specific kinds of statements. void Visit(const Stmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitArraySubscriptExpr - Transfer function for array accesses. void VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *Ex, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitGCCAsmStmt - Transfer function logic for inline asm. void VisitGCCAsmStmt(const GCCAsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitMSAsmStmt - Transfer function logic for MS inline asm. void VisitMSAsmStmt(const MSAsmStmt *A, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitBlockExpr - Transfer function logic for BlockExprs. void VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitBinaryOperator - Transfer function logic for binary operators. void VisitBinaryOperator(const BinaryOperator* B, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitCall - Transfer function for function calls. void VisitCallExpr(const CallExpr *CE, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitCast - Transfer function logic for all casts (implicit and explicit). void VisitCast(const CastExpr *CastE, const Expr *Ex, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitCompoundLiteralExpr - Transfer function logic for compound literals. void VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Transfer function logic for DeclRefExprs and BlockDeclRefExprs. void VisitCommonDeclRefExpr(const Expr *DR, const NamedDecl *D, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitDeclStmt - Transfer function logic for DeclStmts. void VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitGuardedExpr - Transfer function logic for ?, __builtin_choose void VisitGuardedExpr(const Expr *Ex, const Expr *L, const Expr *R, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitInitListExpr(const InitListExpr *E, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitLogicalExpr - Transfer function logic for '&&', '||' void VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitMemberExpr - Transfer function for member expressions. void VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Transfer function logic for ObjCAtSynchronizedStmts. void VisitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Transfer function logic for computing the lvalue of an Objective-C ivar. void VisitLvalObjCIvarRefExpr(const ObjCIvarRefExpr *DR, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitObjCForCollectionStmt - Transfer function logic for /// ObjCForCollectionStmt. void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitObjCMessage(const ObjCMessageExpr *ME, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitReturnStmt - Transfer function logic for return statements. void VisitReturnStmt(const ReturnStmt *R, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitOffsetOfExpr - Transfer function for offsetof. void VisitOffsetOfExpr(const OffsetOfExpr *Ex, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitUnaryExprOrTypeTraitExpr - Transfer function for sizeof. void VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// VisitUnaryOperator - Transfer function logic for unary operators. void VisitUnaryOperator(const UnaryOperator* B, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Handle ++ and -- (both pre- and post-increment). void VisitIncrementDecrementOperator(const UnaryOperator* U, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred, ExplodedNodeSet & Dst); void VisitCXXConstructExpr(const CXXConstructExpr *E, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitCXXDestructor(QualType ObjectType, const MemRegion *Dest, const Stmt *S, bool IsBaseDtor, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred, ExplodedNodeSet &Dst); void VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// Create a C++ temporary object for an rvalue. void CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME, ExplodedNode *Pred, ExplodedNodeSet &Dst); /// evalEagerlyAssumeBinOpBifurcation - Given the nodes in 'Src', eagerly assume symbolic /// expressions of the form 'x != 0' and generate new nodes (stored in Dst) /// with those assumptions. void evalEagerlyAssumeBinOpBifurcation(ExplodedNodeSet &Dst, ExplodedNodeSet &Src, const Expr *Ex); std::pair geteagerlyAssumeBinOpBifurcationTags(); SVal evalMinus(SVal X) { return X.isValid() ? svalBuilder.evalMinus(X.castAs()) : X; } SVal evalComplement(SVal X) { return X.isValid() ? svalBuilder.evalComplement(X.castAs()) : X; } public: SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, NonLoc L, NonLoc R, QualType T) { return svalBuilder.evalBinOpNN(state, op, L, R, T); } SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, NonLoc L, SVal R, QualType T) { return R.isValid() ? svalBuilder.evalBinOpNN(state, op, L, R.castAs(), T) : R; } SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op, SVal LHS, SVal RHS, QualType T) { return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T); } protected: /// evalBind - Handle the semantics of binding a value to a specific location. /// This method is used by evalStore, VisitDeclStmt, and others. void evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE, ExplodedNode *Pred, SVal location, SVal Val, bool atDeclInit = false, const ProgramPoint *PP = 0); /// Call PointerEscape callback when a value escapes as a result of bind. ProgramStateRef processPointerEscapedOnBind(ProgramStateRef State, SVal Loc, SVal Val); /// Call PointerEscape callback when a value escapes as a result of /// region invalidation. /// \param[in] ITraits Specifies invalidation traits for regions/symbols. ProgramStateRef notifyCheckersOfPointerEscape( ProgramStateRef State, const InvalidatedSymbols *Invalidated, ArrayRef ExplicitRegions, ArrayRef Regions, const CallEvent *Call, RegionAndSymbolInvalidationTraits &ITraits); public: // FIXME: 'tag' should be removed, and a LocationContext should be used // instead. // FIXME: Comment on the meaning of the arguments, when 'St' may not // be the same as Pred->state, and when 'location' may not be the // same as state->getLValue(Ex). /// Simulate a read of the result of Ex. void evalLoad(ExplodedNodeSet &Dst, const Expr *NodeEx, /* Eventually will be a CFGStmt */ const Expr *BoundExpr, ExplodedNode *Pred, ProgramStateRef St, SVal location, const ProgramPointTag *tag = 0, QualType LoadTy = QualType()); // FIXME: 'tag' should be removed, and a LocationContext should be used // instead. void evalStore(ExplodedNodeSet &Dst, const Expr *AssignE, const Expr *StoreE, ExplodedNode *Pred, ProgramStateRef St, SVal TargetLV, SVal Val, const ProgramPointTag *tag = 0); /// \brief Create a new state in which the call return value is binded to the /// call origin expression. ProgramStateRef bindReturnValue(const CallEvent &Call, const LocationContext *LCtx, ProgramStateRef State); /// Evaluate a call, running pre- and post-call checks and allowing checkers /// to be responsible for handling the evaluation of the call itself. void evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred, const CallEvent &Call); /// \brief Default implementation of call evaluation. void defaultEvalCall(NodeBuilder &B, ExplodedNode *Pred, const CallEvent &Call); private: void evalLoadCommon(ExplodedNodeSet &Dst, const Expr *NodeEx, /* Eventually will be a CFGStmt */ const Expr *BoundEx, ExplodedNode *Pred, ProgramStateRef St, SVal location, const ProgramPointTag *tag, QualType LoadTy); // FIXME: 'tag' should be removed, and a LocationContext should be used // instead. void evalLocation(ExplodedNodeSet &Dst, const Stmt *NodeEx, /* This will eventually be a CFGStmt */ const Stmt *BoundEx, ExplodedNode *Pred, ProgramStateRef St, SVal location, const ProgramPointTag *tag, bool isLoad); /// Count the stack depth and determine if the call is recursive. void examineStackFrames(const Decl *D, const LocationContext *LCtx, bool &IsRecursive, unsigned &StackDepth); /// Checks our policies and decides weither the given call should be inlined. bool shouldInlineCall(const CallEvent &Call, const Decl *D, const ExplodedNode *Pred); bool inlineCall(const CallEvent &Call, const Decl *D, NodeBuilder &Bldr, ExplodedNode *Pred, ProgramStateRef State); /// \brief Conservatively evaluate call by invalidating regions and binding /// a conjured return value. void conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr, ExplodedNode *Pred, ProgramStateRef State); /// \brief Either inline or process the call conservatively (or both), based /// on DynamicDispatchBifurcation data. void BifurcateCall(const MemRegion *BifurReg, const CallEvent &Call, const Decl *D, NodeBuilder &Bldr, ExplodedNode *Pred); bool replayWithoutInlining(ExplodedNode *P, const LocationContext *CalleeLC); /// Models a trivial copy or move constructor or trivial assignment operator /// call with a simple bind. void performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred, const CallEvent &Call); /// If the value of the given expression is a NonLoc, copy it into a new /// temporary object region, and replace the value of the expression with /// that. /// /// If \p ResultE is provided, the new region will be bound to this expression /// instead of \p E. ProgramStateRef createTemporaryRegionIfNeeded(ProgramStateRef State, const LocationContext *LC, const Expr *E, const Expr *ResultE = 0); }; /// Traits for storing the call processing policy inside GDM. /// The GDM stores the corresponding CallExpr pointer. // FIXME: This does not use the nice trait macros because it must be accessible // from multiple translation units. struct ReplayWithoutInlining{}; template <> struct ProgramStateTrait : public ProgramStatePartialTrait { static void *GDMIndex() { static int index = 0; return &index; } }; } // end ento namespace } // end clang namespace #endif