//===- ExprEngine.h - Path-Sensitive Expression-Level Dataflow --*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  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_STATICANALYZER_CORE_PATHSENSITIVE_EXPRENGINE_H

#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_EXPRENGINE_H

#include "clang/AST/Expr.h"

#include "clang/AST/Type.h"

#include "clang/Analysis/CFG.h"

#include "clang/Analysis/DomainSpecific/ObjCNoReturn.h"

#include "clang/Analysis/ProgramPoint.h"

#include "clang/Basic/LLVM.h"

#include "clang/StaticAnalyzer/Core/CheckerManager.h"

#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"

#include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CoreEngine.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/FunctionSummary.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/WorkList.h"

#include "llvm/ADT/ArrayRef.h"

#include <cassert>

#include <utility>

namespace clang {

class AnalysisDeclContextManager;

class AnalyzerOptions;

class ASTContext;

class CFGBlock;

class CFGElement;

class ConstructionContext;

class CXXBindTemporaryExpr;

class CXXCatchStmt;

class CXXConstructExpr;

class CXXDeleteExpr;

class CXXNewExpr;

class CXXThisExpr;

class Decl;

class DeclStmt;

class GCCAsmStmt;

class LambdaExpr;

class LocationContext;

class MaterializeTemporaryExpr;

class MSAsmStmt;

class NamedDecl;

class ObjCAtSynchronizedStmt;

class ObjCForCollectionStmt;

class ObjCIvarRefExpr;

class ObjCMessageExpr;

class ReturnStmt;

class Stmt;

namespace cross_tu {

class CrossTranslationUnitContext;

} // namespace cross_tu

namespace ento {

class AnalysisManager;

class BasicValueFactory;

class BlockCounter;

class BranchNodeBuilder;

class CallEvent;

class CheckerManager;

class ConstraintManager;

class CXXTempObjectRegion;

class EndOfFunctionNodeBuilder;

class ExplodedNodeSet;

class ExplodedNode;

class IndirectGotoNodeBuilder;

class MemRegion;

struct NodeBuilderContext;

class NodeBuilderWithSinks;

class ProgramState;

class ProgramStateManager;

class RegionAndSymbolInvalidationTraits;

class SymbolManager;

class SwitchNodeBuilder;

/// Hints for figuring out of a call should be inlined during evalCall().

struct EvalCallOptions {

  /// This call is a constructor or a destructor for which we do not currently

  /// compute the this-region correctly.

  bool IsCtorOrDtorWithImproperlyModeledTargetRegion = false;

  /// This call is a constructor or a destructor for a single element within

  /// an array, a part of array construction or destruction.

  bool IsArrayCtorOrDtor = false;

  /// This call is a constructor or a destructor of a temporary value.

  bool IsTemporaryCtorOrDtor = false;

  /// This call is a constructor for a temporary that is lifetime-extended

  /// by binding it to a reference-type field within an aggregate,

  /// for example 'A { const C &c; }; A a = { C() };'

  bool IsTemporaryLifetimeExtendedViaAggregate = false;

  /// This call is a pre-C++17 elidable constructor that we failed to elide

  /// because we failed to compute the target region into which

  /// this constructor would have been ultimately elided. Analysis that

  /// we perform in this case is still correct but it behaves differently,

  /// as if copy elision is disabled.

  bool IsElidableCtorThatHasNotBeenElided = false;

  EvalCallOptions() {}

};

class ExprEngine {

  void anchor();

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:

  cross_tu::CrossTranslationUnitContext &CTU;

  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;

  /// MRMgr - MemRegionManager object that creates memory regions.

  MemRegionManager &MRMgr;

  /// svalBuilder - SValBuilder object that creates SVals from expressions.

  SValBuilder &svalBuilder;

  unsigned int currStmtIdx = 0;

  const NodeBuilderContext *currBldrCtx = nullptr;

  /// Helper object to determine if an Objective-C message expression

  /// implicitly never returns.

  ObjCNoReturn ObjCNoRet;

  /// 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.

  PathSensitiveBugReporter 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(cross_tu::CrossTranslationUnitContext &CTU, AnalysisManager &mgr,

             SetOfConstDecls *VisitedCalleesIn,

             FunctionSummariesTy *FS, InliningModes HowToInlineIn);

  virtual ~ExprEngine() = default;

  /// Returns true if there is still simulation state on the worklist.

  bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {

    return Engine.ExecuteWorkList(L, Steps, nullptr);

  }

  /// 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(); }

  AnalysisManager &getAnalysisManager() { return AMgr; }

  AnalysisDeclContextManager &getAnalysisDeclContextManager() {

    return AMgr.getAnalysisDeclContextManager();

  }

  CheckerManager &getCheckerManager() const {

    return *AMgr.getCheckerManager();

  }

  SValBuilder &getSValBuilder() { return svalBuilder; }

  BugReporter &getBugReporter() { return BR; }

  cross_tu::CrossTranslationUnitContext *

  getCrossTranslationUnitContext() {

    return &CTU;

  }

  const NodeBuilderContext &getBuilderContext() {

    assert(currBldrCtx);

    return *currBldrCtx;

  }

  const Stmt *getStmt() const;

  void GenerateAutoTransition(ExplodedNode *N);

  void enqueueEndOfPath(ExplodedNodeSet &S);

  void GenerateCallExitNode(ExplodedNode *N);

  /// Dump graph to the specified filename.

  /// If filename is empty, generate a temporary one.

  /// \return The filename the graph is written into.

  std::string DumpGraph(bool trim = false, StringRef Filename="");

  /// Dump the graph consisting of the given nodes to a specified filename.

  /// Generate a temporary filename if it's not provided.

  /// \return The filename the graph is written into.

  std::string DumpGraph(ArrayRef<const ExplodedNode *> Nodes,

                        StringRef Filename = "");

  /// 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<const ExplodedNode *> 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; }

  /// 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 = nullptr,

            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 Stmt *S, ExplodedNode *Pred);

  void ProcessLoopExit(const Stmt* S, ExplodedNode *Pred);

  void ProcessInitializer(const CFGInitializer I, ExplodedNode *Pred);

  void ProcessImplicitDtor(const CFGImplicitDtor D, ExplodedNode *Pred);

  void ProcessNewAllocator(const CXXNewExpr *NE, 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.

  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,

                     NodeBuilderContext& BuilderCtx,

                     ExplodedNode *Pred,

                     ExplodedNodeSet &Dst,

                     const CFGBlock *DstT,

                     const CFGBlock *DstF);

  /// Called by CoreEngine.

  /// Used to generate successor nodes for temporary destructors depending

  /// on whether the corresponding constructor was visited.

  void processCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,

                                     NodeBuilderContext &BldCtx,

                                     ExplodedNode *Pred, ExplodedNodeSet &Dst,

                                     const CFGBlock *DstT,

                                     const CFGBlock *DstF);

  /// Called by CoreEngine.  Used to processing branching behavior

  /// at static initializers.

  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 notify checkers that processing a

  /// function has begun. Called for both inlined and and top-level functions.

  void processBeginOfFunction(NodeBuilderContext &BC,

                              ExplodedNode *Pred, ExplodedNodeSet &Dst,

                              const BlockEdge &L);

  /// Called by CoreEngine.  Used to notify checkers that processing a

  /// function has ended. Called for both inlined and and top-level functions.

  void processEndOfFunction(NodeBuilderContext& BC,

                            ExplodedNode *Pred,

                            const ReturnStmt *RS = nullptr);

  /// 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(NodeBuilderContext& BC, 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();

  /// evalAssume - Callback function invoked by the ConstraintManager when

  ///  making assumptions about state values.

  ProgramStateRef processAssume(ProgramStateRef state, SVal cond,

                                bool assumption);

  /// 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<const MemRegion *> ExplicitRegions,

                       ArrayRef<const MemRegion *> Regions,

                       const LocationContext *LCtx,

                       const CallEvent *Call);

  inline ProgramStateRef

  processRegionChange(ProgramStateRef state,

                      const MemRegion* MR,

                      const LocationContext *LCtx) {

    return processRegionChanges(state, nullptr, MR, MR, LCtx, nullptr);

  }

  /// printJson - Called by ProgramStateManager to print checker-specific data.

  void printJson(raw_ostream &Out, ProgramStateRef State,

                 const LocationContext *LCtx, const char *NL,

                 unsigned int Space, bool IsDot) const;

  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();

  }

  SymbolManager &getSymbolManager() { return SymMgr; }

  MemRegionManager &getRegionManager() { return MRMgr; }

  DataTag::Factory &getDataTags() { return Engine.getDataTags(); }

  // 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 VisitArraySubscriptExpr(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);

  /// VisitLambdaExpr - Transfer function logic for LambdaExprs.

  void VisitLambdaExpr(const LambdaExpr *LE, 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);

  /// VisitAtomicExpr - Transfer function for builtin atomic expressions

  void VisitAtomicExpr(const AtomicExpr *E, 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 VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *BTE,

                                 ExplodedNodeSet &PreVisit,

                                 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 VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E,

                                     ExplodedNode *Pred, ExplodedNodeSet &Dst);

  void VisitCXXDestructor(QualType ObjectType, const MemRegion *Dest,

                          const Stmt *S, bool IsBaseDtor,

                          ExplodedNode *Pred, ExplodedNodeSet &Dst,

                          EvalCallOptions &Options);

  void VisitCXXNewAllocatorCall(const CXXNewExpr *CNE,

                                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);

  static std::pair<const ProgramPointTag *, const ProgramPointTag *>

    geteagerlyAssumeBinOpBifurcationTags();

  SVal evalMinus(SVal X) {

    return X.isValid() ? svalBuilder.evalMinus(X.castAs<NonLoc>()) : 
X0
;

  }

  SVal evalComplement(SVal X) {

    return X.isValid() ? svalBuilder.evalComplement(X.castAs<NonLoc>()) : 
X0
;

  }

  ProgramStateRef handleLValueBitCast(ProgramStateRef state, const Expr *Ex,

                                      const LocationContext *LCtx, QualType T,

                                      QualType ExTy, const CastExpr *CastE,

                                      StmtNodeBuilder &Bldr,

                                      ExplodedNode *Pred);

  ProgramStateRef handleLVectorSplat(ProgramStateRef state,

                                     const LocationContext *LCtx,

                                     const CastExpr *CastE,

                                     StmtNodeBuilder &Bldr,

                                     ExplodedNode *Pred);

  void handleUOExtension(ExplodedNodeSet::iterator I,

                         const UnaryOperator* U,

                         StmtNodeBuilder &Bldr);

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<NonLoc>(), T) : R;

  }

  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,

                 SVal LHS, SVal RHS, QualType T) {

    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);

  }

  /// By looking at a certain item that may be potentially part of an object's

  /// ConstructionContext, retrieve such object's location. A particular

  /// statement can be transparently passed as \p Item in most cases.

  static Optional<SVal>

  getObjectUnderConstruction(ProgramStateRef State,

                             const ConstructionContextItem &Item,

                             const LocationContext *LC);

  /// Call PointerEscape callback when a value escapes as a result of bind.

  ProgramStateRef processPointerEscapedOnBind(

      ProgramStateRef State, ArrayRef<std::pair<SVal, SVal>> LocAndVals,

      const LocationContext *LCtx, PointerEscapeKind Kind,

      const CallEvent *Call);

  /// 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<const MemRegion *> ExplicitRegions,

                           const CallEvent *Call,

                           RegionAndSymbolInvalidationTraits &ITraits);

private:

  /// 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 = nullptr);

  ProgramStateRef

  processPointerEscapedOnBind(ProgramStateRef State,

                              SVal Loc, SVal Val,

                              const LocationContext *LCtx);

  /// A simple wrapper when you only need to notify checkers of pointer-escape

  /// of some values.

  ProgramStateRef escapeValues(ProgramStateRef State, ArrayRef<SVal> Vs,

                               PointerEscapeKind K,

                               const CallEvent *Call = nullptr) const;

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 = nullptr,

                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 = nullptr);

  /// Return the CFG element corresponding to the worklist element

  /// that is currently being processed by ExprEngine.

  CFGElement getCurrentCFGElement() {

    return (*currBldrCtx->getBlock())[currStmtIdx];

  }

  /// 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 checkers and allowing checkers

  /// to be responsible for handling the evaluation of the call itself.

  void evalCall(ExplodedNodeSet &Dst, ExplodedNode *Pred,

                const CallEvent &Call);

  /// Default implementation of call evaluation.

  void defaultEvalCall(NodeBuilder &B, ExplodedNode *Pred,

                       const CallEvent &Call,

                       const EvalCallOptions &CallOpts = {});

  /// Find location of the object that is being constructed by a given

  /// constructor. This should ideally always succeed but due to not being

  /// fully implemented it sometimes indicates that it failed via its

  /// out-parameter CallOpts; in such cases a fake temporary region is

  /// returned, which is better than nothing but does not represent

  /// the actual behavior of the program.

  SVal computeObjectUnderConstruction(

      const Expr *E, ProgramStateRef State, const LocationContext *LCtx,

      const ConstructionContext *CC, EvalCallOptions &CallOpts);

  /// Update the program state with all the path-sensitive information

  /// that's necessary to perform construction of an object with a given

  /// syntactic construction context. V and CallOpts have to be obtained from

  /// computeObjectUnderConstruction() invoked with the same set of

  /// the remaining arguments (E, State, LCtx, CC).

  ProgramStateRef updateObjectsUnderConstruction(

      SVal V, const Expr *E, ProgramStateRef State, const LocationContext *LCtx,

      const ConstructionContext *CC, const EvalCallOptions &CallOpts);

  /// A convenient wrapper around computeObjectUnderConstruction

  /// and updateObjectsUnderConstruction.

  std::pair<ProgramStateRef, SVal> handleConstructionContext(

      const Expr *E, ProgramStateRef State, const LocationContext *LCtx,

      const ConstructionContext *CC, EvalCallOptions &CallOpts) {

    SVal V = computeObjectUnderConstruction(E, State, LCtx, CC, CallOpts);

    return std::make_pair(

        updateObjectsUnderConstruction(V, E, State, LCtx, CC, CallOpts), V);

  }

private:

  ProgramStateRef finishArgumentConstruction(ProgramStateRef State,

                                             const CallEvent &Call);

  void finishArgumentConstruction(ExplodedNodeSet &Dst, ExplodedNode *Pred,

                                  const CallEvent &Call);

  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);

  void evalLocation(ExplodedNodeSet &Dst,

                    const Stmt *NodeEx, /* This will eventually be a CFGStmt */

                    const Stmt *BoundEx,

                    ExplodedNode *Pred,

                    ProgramStateRef St,

                    SVal location,

                    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);

  enum CallInlinePolicy {

    CIP_Allowed,

    CIP_DisallowedOnce,

    CIP_DisallowedAlways

  };

  /// See if a particular call should be inlined, by only looking

  /// at the call event and the current state of analysis.

  CallInlinePolicy mayInlineCallKind(const CallEvent &Call,

                                     const ExplodedNode *Pred,

                                     AnalyzerOptions &Opts,

                                     const EvalCallOptions &CallOpts);

  /// See if the given AnalysisDeclContext is built for a function that we

  /// should always inline simply because it's small enough.

  /// Apart from "small" functions, we also have "large" functions

  /// (cf. isLarge()), some of which are huge (cf. isHuge()), and we classify

  /// the remaining functions as "medium".

  bool isSmall(AnalysisDeclContext *ADC) const;

  /// See if the given AnalysisDeclContext is built for a function that we

  /// should inline carefully because it looks pretty large.

  bool isLarge(AnalysisDeclContext *ADC) const;

  /// See if the given AnalysisDeclContext is built for a function that we

  /// should never inline because it's legit gigantic.

  bool isHuge(AnalysisDeclContext *ADC) const;

  /// See if the given AnalysisDeclContext is built for a function that we

  /// should inline, just by looking at the declaration of the function.

  bool mayInlineDecl(AnalysisDeclContext *ADC) const;

  /// Checks our policies and decides weither the given call should be inlined.

  bool shouldInlineCall(const CallEvent &Call, const Decl *D,

                        const ExplodedNode *Pred,

                        const EvalCallOptions &CallOpts = {});

  bool inlineCall(const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,

                  ExplodedNode *Pred, ProgramStateRef State);

  /// Conservatively evaluate call by invalidating regions and binding

  /// a conjured return value.

  void conservativeEvalCall(const CallEvent &Call, NodeBuilder &Bldr,

                            ExplodedNode *Pred, ProgramStateRef State);

  /// 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 \p InitWithAdjustments is a NonLoc,

  /// copy it into a new temporary object region, and replace the value of the

  /// expression with that.

  ///

  /// If \p Result is provided, the new region will be bound to this expression

  /// instead of \p InitWithAdjustments.

  ///

  /// Returns the temporary region with adjustments into the optional

  /// OutRegionWithAdjustments out-parameter if a new region was indeed needed,

  /// otherwise sets it to nullptr.

  ProgramStateRef createTemporaryRegionIfNeeded(

      ProgramStateRef State, const LocationContext *LC,

      const Expr *InitWithAdjustments, const Expr *Result = nullptr,

      const SubRegion **OutRegionWithAdjustments = nullptr);

  /// Returns a region representing the first element of a (possibly

  /// multi-dimensional) array, for the purposes of element construction or

  /// destruction.

  ///

  /// On return, \p Ty will be set to the base type of the array.

  ///

  /// If the type is not an array type at all, the original value is returned.

  /// Otherwise the "IsArray" flag is set.

  static SVal makeZeroElementRegion(ProgramStateRef State, SVal LValue,

                                    QualType &Ty, bool &IsArray);

  /// For a DeclStmt or CXXInitCtorInitializer, walk backward in the current CFG

  /// block to find the constructor expression that directly constructed into

  /// the storage for this statement. Returns null if the constructor for this

  /// statement created a temporary object region rather than directly

  /// constructing into an existing region.

  const CXXConstructExpr *findDirectConstructorForCurrentCFGElement();

  /// Common code that handles either a CXXConstructExpr or a

  /// CXXInheritedCtorInitExpr.

  void handleConstructor(const Expr *E, ExplodedNode *Pred,

                         ExplodedNodeSet &Dst);

public:

  /// Note whether this loop has any more iteratios to model. These methods are

  /// essentially an interface for a GDM trait. Further reading in

  /// ExprEngine::VisitObjCForCollectionStmt().

  LLVM_NODISCARD static ProgramStateRef

  setWhetherHasMoreIteration(ProgramStateRef State,

                             const ObjCForCollectionStmt *O,

                             const LocationContext *LC, bool HasMoreIteraton);

  LLVM_NODISCARD static ProgramStateRef

  removeIterationState(ProgramStateRef State, const ObjCForCollectionStmt *O,

                       const LocationContext *LC);

  LLVM_NODISCARD static bool hasMoreIteration(ProgramStateRef State,

                                              const ObjCForCollectionStmt *O,

                                              const LocationContext *LC);

private:

  /// Store the location of a C++ object corresponding to a statement

  /// until the statement is actually encountered. For example, if a DeclStmt

  /// has CXXConstructExpr as its initializer, the object would be considered

  /// to be "under construction" between CXXConstructExpr and DeclStmt.

  /// This allows, among other things, to keep bindings to variable's fields

  /// made within the constructor alive until its declaration actually

  /// goes into scope.

  static ProgramStateRef

  addObjectUnderConstruction(ProgramStateRef State,

                             const ConstructionContextItem &Item,

                             const LocationContext *LC, SVal V);

  /// Mark the object sa fully constructed, cleaning up the state trait

  /// that tracks objects under construction.

  static ProgramStateRef

  finishObjectConstruction(ProgramStateRef State,

                           const ConstructionContextItem &Item,

                           const LocationContext *LC);

  /// If the given expression corresponds to a temporary that was used for

  /// passing into an elidable copy/move constructor and that constructor

  /// was actually elided, track that we also need to elide the destructor.

  static ProgramStateRef elideDestructor(ProgramStateRef State,

                                         const CXXBindTemporaryExpr *BTE,

                                         const LocationContext *LC);

  /// Stop tracking the destructor that corresponds to an elided constructor.

  static ProgramStateRef

  cleanupElidedDestructor(ProgramStateRef State,

                          const CXXBindTemporaryExpr *BTE,

                          const LocationContext *LC);

  /// Returns true if the given expression corresponds to a temporary that

  /// was constructed for passing into an elidable copy/move constructor

  /// and that constructor was actually elided.

  static bool isDestructorElided(ProgramStateRef State,

                                 const CXXBindTemporaryExpr *BTE,

                                 const LocationContext *LC);

  /// Check if all objects under construction have been fully constructed

  /// for the given context range (including FromLC, not including ToLC).

  /// This is useful for assertions. Also checks if elided destructors

  /// were cleaned up.

  static bool areAllObjectsFullyConstructed(ProgramStateRef State,

                                            const LocationContext *FromLC,

                                            const LocationContext *ToLC);

};

/// 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<ReplayWithoutInlining> :

  public ProgramStatePartialTrait<const void*> {

  static void *GDMIndex();

};

} // namespace ento

} // namespace clang

#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_EXPRENGINE_H