ExprEngine.h

Go to the documentation of this file.

//===- 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 <optional>
#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 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 CallEvent;
class CheckerManager;
class ConstraintManager;
class ExplodedNodeSet;
class ExplodedNode;
class MemRegion;
class NodeBuilderContext;
class ProgramState;
class ProgramStateManager;
class RegionAndSymbolInvalidationTraits;
class SymbolManager;
 
/// Hints for figuring out if 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;
  bool IsCTUEnabled;
 
  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;
 
  /// Pointer to a (so-called, somewhat misnamed) NodeBuilderContext object
  /// which has three independent roles:
  /// - It holds a pointer to the CFGBlock that is currently under analysis.
  ///   (This is the primary way to get the current block.)
  /// - It holds a pointer to the current StackFrame. (This is rarely
  ///   used, the stack frame is usually queried from a recent
  ///   ExplodedNode. Unfortunately it seems that these two sources of truth
  ///   are not always consistent.)
  /// - It can be used for constructing `NodeBuilder`s. Practically all
  ///   `NodeBuilder` objects are useless complications in the code, so I
  ///   intend to replace them with direct use of `CoreEngine::makeNode`.
  /// TODO: Eventually `currBldrCtx` should be replaced by two separate fields:
  /// `const CFGBlock *CurrBlock` & `const StackFrame *CurrStackFrame`
  /// that are kept up-to-date and are almost always non-null during the
  /// analysis. I will switch to this more natural representation when
  /// `NodeBuilder`s are eliminated from the code.
  const NodeBuilderContext *currBldrCtx = nullptr;
  /// Historically `currBldrCtx` pointed to a local variable in some stack
  /// frame. This field is introduced as a temporary measure to allow a gradual
  /// transition. Only use this in {re,}setCurrStackFrameAndBlock!
  /// TODO: Remove this temporary hack.
  std::optional<NodeBuilderContext> OwnedCurrBldrCtx;
 
  /// 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 StackFrame *SF, unsigned Steps = 150000) {
    assert(SF->inTopFrame());
    BR.setAnalysisEntryPoint(SF->getDecl());
    return Engine.ExecuteWorkList(SF, Steps, nullptr);
  }
 
  /// getContext - Return the ASTContext associated with this analysis.
  ASTContext &getContext() const { return AMgr.getASTContext(); }
 
  AnalysisManager &getAnalysisManager() { return AMgr; }
  const AnalysisManager &getAnalysisManager() const { return AMgr; }
 
  AnalysisDeclContextManager &getAnalysisDeclContextManager() {
    return AMgr.getAnalysisDeclContextManager();
  }
 
  CheckerManager &getCheckerManager() const {
    return *AMgr.getCheckerManager();
  }
 
  SValBuilder &getSValBuilder() { return svalBuilder; }
  const SValBuilder &getSValBuilder() const { return svalBuilder; }
 
  BugReporter &getBugReporter() { return BR; }
  const BugReporter &getBugReporter() const { return BR; }
 
  cross_tu::CrossTranslationUnitContext *
  getCrossTranslationUnitContext() {
    return &CTU;
  }
 
  // FIXME: Ideally the body of this method should look like
  //   CurrStackFrame = SF;
  //   CurrBlock = B;
  // where CurrStackFrame and CurrBlock are new member variables that
  // fulfill the roles of `currBldrCtx` in a more natural way.
  // This implementation is a temporary measure to allow a gradual transition.
  void setCurrStackFrameAndBlock(const StackFrame *SF, const CFGBlock *B) {
    // The current StackFrame and Block is reset at the beginning of
    // dispatchWorkItem. Ideally, this method should be called only once per
    // dispatchWorkItem call (= elementary analysis step); so the following
    // assertion is there to catch accidental repeated calls. If the current
    // StackFrame and Block needs to change in the middle of a single step
    // (which currently happens only once, in processCallExit), use an explicit
    // call to resetCurrStackFrameAndBlock.
    assert(!currBldrCtx && !OwnedCurrBldrCtx &&
           "The current StackFrame and Block is already set");
    OwnedCurrBldrCtx.emplace(Engine, B, SF);
    currBldrCtx = &*OwnedCurrBldrCtx;
  }
 
  void resetCurrStackFrameAndBlock() {
    currBldrCtx = nullptr;
    OwnedCurrBldrCtx = std::nullopt;
  }
 
  const NodeBuilderContext &getBuilderContext() const {
    assert(currBldrCtx);
    return *currBldrCtx;
  }
 
  const StackFrame *getRootStackFrame() const {
    assert(G.getRoot());
    return G.getRoot()->getLocation().getStackFrame();
  }
 
  /// Get the 'current' stack frame corresponding to the current work item
  /// (elementary analysis step handled by `dispatchWorkItem`).
  /// FIXME: This sometimes (e.g. in some `BeginFunction` callbacks) differs
  /// from the `StackFrame` that can be obtained from different sources
  /// (e.g. a recent `ExplodedNode`). Traditionally this stack frame is
  /// only used for block count calculations (`getNumVisited`); it is probably
  /// wise to follow this tradition until the discrepancies are resolved.
  const StackFrame *getCurrStackFrame() const {
    return currBldrCtx ? currBldrCtx->getStackFrame() : nullptr;
  }
 
  /// Get the 'current' CFGBlock corresponding to the current work item
  /// (elementary analysis step handled by `dispatchWorkItem`).
  const CFGBlock *getCurrBlock() const {
    return currBldrCtx ? currBldrCtx->getBlock() : nullptr;
  }
 
  ConstCFGElementRef getCFGElementRef() const {
    return {getCurrBlock(), currStmtIdx};
  }
 
  unsigned getNumVisited(const StackFrame *SF, const CFGBlock *Block) const {
    return Engine.WList->getBlockCounter().getNumVisited(SF,
                                                         Block->getBlockID());
  }
 
  unsigned getNumVisitedCurrent() const {
    return getNumVisited(getCurrStackFrame(), getCurrBlock());
  }
 
  /// 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 StackFrame *InitSF);
 
  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 StackFrames
  ///        is dead.
  /// \param SF The stack frame of the \p ReferenceStmt. A null stack frame
  ///        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 stack frame 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 StackFrame *SF,
             const Stmt *DiagnosticStmt = nullptr,
             ProgramPoint::Kind K = ProgramPoint::PreStmtPurgeDeadSymbolsKind);
 
  /// A tag to track convenience transitions, which can be removed at cleanup.
  /// This tag applies to a node created after removeDead.
  static const ProgramPointTag *cleanupNodeTag();
 
  /// 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);
 
  void ProcessStmt(const Stmt *S, ExplodedNode *Pred);
 
  void ProcessLoopExit(const Stmt* S, ExplodedNode *Pred);
  void ProcessLifetimeEnd(const Stmt *S, const VarDecl *D, 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, const BlockEntrance &BE,
                               NodeBuilder &Builder, ExplodedNode *Pred);
 
  void runCheckersForBlockEntrance(const BlockEntrance &Entrance,
                                   ExplodedNode *Pred, ExplodedNodeSet &Dst);
 
  /// ProcessBranch - Called by CoreEngine. Used to generate successor nodes by
  /// processing the 'effects' of a branch condition. If the branch condition
  /// is a loop condition, IterationsCompletedInLoop is the number of completed
  /// iterations (otherwise it's std::nullopt).
  void processBranch(const Stmt *Condition, ExplodedNode *Pred,
                     ExplodedNodeSet &Dst, const CFGBlock *DstT,
                     const CFGBlock *DstF,
                     std::optional<unsigned> IterationsCompletedInLoop);
 
  /// Called by CoreEngine.
  /// Used to generate successor nodes for temporary destructors depending
  /// on whether the corresponding constructor was visited.
  void processCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,
                                     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, 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(ExplodedNodeSet &Dst, const Expr *Tgt,
                           const CFGBlock *Dispatch, ExplodedNode *Pred);
 
  /// ProcessSwitch - Called by CoreEngine. Used to generate successor
  ///  nodes by processing the 'effects' of a switch statement.
  void processSwitch(const SwitchStmt *Switch, ExplodedNode *Pred,
                     ExplodedNodeSet &Dst);
 
  /// Called by CoreEngine. Used to notify checkers that processing a
  /// function has begun. Called for both inlined and top-level functions.
  void processBeginOfFunction(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 top-level functions.
  void processEndOfFunction(ExplodedNode *Pred, const ReturnStmt *RS = nullptr);
 
  /// Remove dead bindings/symbols before exiting a function.
  void removeDeadOnEndOfFunction(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();
 
  /// 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 StackFrame *SF, const CallEvent *Call);
 
  inline ProgramStateRef processRegionChange(ProgramStateRef state,
                                             const MemRegion *MR,
                                             const StackFrame *SF) {
    return processRegionChanges(state, nullptr, MR, MR, SF, nullptr);
  }
 
  /// printJson - Called by ProgramStateManager to print checker-specific data.
  void printJson(raw_ostream &Out, ProgramStateRef State, const StackFrame *SF,
                 const char *NL, unsigned int Space, bool IsDot) const;
 
  ProgramStateManager &getStateManager() { return StateMgr; }
  const ProgramStateManager &getStateManager() const { return StateMgr; }
 
  StoreManager &getStoreManager() { return StateMgr.getStoreManager(); }
  const StoreManager &getStoreManager() const {
    return StateMgr.getStoreManager();
  }
 
  ConstraintManager &getConstraintManager() {
    return StateMgr.getConstraintManager();
  }
  const ConstraintManager &getConstraintManager() const {
    return StateMgr.getConstraintManager();
  }
 
  // FIXME: Remove when we migrate over to just using SValBuilder.
  BasicValueFactory &getBasicVals() {
    return StateMgr.getBasicVals();
  }
 
  SymbolManager &getSymbolManager() { return SymMgr; }
  const SymbolManager &getSymbolManager() const { 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);
 
  /// VisitArrayInitLoopExpr - Transfer function for array init loop.
  void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *Ex, 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);
 
  /// VisitAttributedStmt - Transfer function logic for AttributedStmt.
  void VisitAttributedStmt(const AttributedStmt *A, 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);
 
  void ConstructInitList(const Expr *Source, ArrayRef<Expr *> Args,
                         bool IsTransparent, ExplodedNode *Pred,
                         ExplodedNodeSet &Dst);
 
  /// evalEagerlyAssumeBifurcation - Given the nodes in 'Src', eagerly assume
  /// concrete boolean values for 'Ex', storing the resulting nodes in 'Dst'.
  void evalEagerlyAssumeBifurcation(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
                                    const Expr *Ex);
 
  bool didEagerlyAssumeBifurcateAt(ProgramStateRef State, const Expr *Ex) const;
 
  static std::pair<const ProgramPointTag *, const ProgramPointTag *>
  getEagerlyAssumeBifurcationTags();
 
  ProgramStateRef handleLValueBitCast(ProgramStateRef state, const Expr *Ex,
                                      const StackFrame *SF, QualType T,
                                      QualType ExTy, const CastExpr *CastE,
                                      NodeBuilder &Bldr, ExplodedNode *Pred);
 
  void handleUOExtension(ExplodedNode *N, const UnaryOperator *U,
                         NodeBuilder &Bldr);
 
public:
  SVal evalBinOp(ProgramStateRef ST, BinaryOperator::Opcode Op,
                 SVal LHS, SVal RHS, QualType T) {
    return svalBuilder.evalBinOp(ST, Op, LHS, RHS, T);
  }
 
  /// Retrieves which element is being constructed in a non-POD type array.
  static std::optional<unsigned>
  getIndexOfElementToConstruct(ProgramStateRef State, const CXXConstructExpr *E,
                               const StackFrame *SF);
 
  /// Retrieves which element is being destructed in a non-POD type array.
  static std::optional<unsigned>
  getPendingArrayDestruction(ProgramStateRef State, const StackFrame *SF);
 
  /// Retrieves the size of the array in the pending ArrayInitLoopExpr.
  static std::optional<unsigned> getPendingInitLoop(ProgramStateRef State,
                                                    const CXXConstructExpr *E,
                                                    const StackFrame *SF);
 
  /// 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 std::optional<SVal>
  getObjectUnderConstruction(ProgramStateRef State,
                             const ConstructionContextItem &Item,
                             const StackFrame *SF);
 
  /// Call PointerEscape callback when a value escapes as a result of bind.
  ProgramStateRef processPointerEscapedOnBind(
      ProgramStateRef State, ArrayRef<std::pair<SVal, SVal>> LocAndVals,
      const StackFrame *SF, 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 StackFrame *SF);
 
public:
  /// 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;
 
  // FIXME: 'tag' should be removed, and a StackFrame 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 StackFrame 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 (*getCurrBlock())[currStmtIdx]; }
 
  /// Create a new state in which the call return value is binded to the
  /// call origin expression.
  ProgramStateRef bindReturnValue(const CallEvent &Call, const StackFrame *SF,
                                  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. The Idx parameter is used if we
  /// construct an array of objects. In that case it points to the index
  /// of the continuous memory region.
  /// E.g.:
  /// For `int arr[4]` this index can be 0,1,2,3.
  /// For `int arr2[3][3]` this index can be 0,1,...,7,8.
  /// A multi-dimensional array is also a continuous memory location in a
  /// row major order, so for arr[0][0] Idx is 0 and for arr[3][3] Idx is 8.
  SVal computeObjectUnderConstruction(const Expr *E, ProgramStateRef State,
                                      unsigned NumVisitedCaller,
                                      const StackFrame *SF,
                                      const ConstructionContext *CC,
                                      EvalCallOptions &CallOpts,
                                      unsigned Idx = 0);
 
  /// 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, SF, CC).
  ProgramStateRef updateObjectsUnderConstruction(
      SVal V, const Expr *E, ProgramStateRef State, const StackFrame *SF,
      const ConstructionContext *CC, const EvalCallOptions &CallOpts);
 
  /// A convenient wrapper around computeObjectUnderConstruction
  /// and updateObjectsUnderConstruction.
  std::pair<ProgramStateRef, SVal>
  handleConstructionContext(const Expr *E, ProgramStateRef State,
                            const NodeBuilderContext *BldrCtx,
                            const StackFrame *SF, const ConstructionContext *CC,
                            EvalCallOptions &CallOpts, unsigned Idx = 0) {
 
    SVal V = computeObjectUnderConstruction(E, State, BldrCtx->blockCount(), SF,
                                            CC, CallOpts, Idx);
    State = updateObjectsUnderConstruction(V, E, State, SF, CC, CallOpts);
 
    return std::make_pair(State, V);
  }
 
private:
  ProgramStateRef finishArgumentConstruction(ProgramStateRef State,
                                             const CallEvent &Call);
  void finishArgumentConstruction(ExplodedNodeSet &Dst, ExplodedNode *Pred,
                                  const CallEvent &Call);
 
  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 StackFrame *SF,
                          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 whether the given call should be inlined.
  bool shouldInlineCall(const CallEvent &Call, const Decl *D,
                        const ExplodedNode *Pred,
                        const EvalCallOptions &CallOpts = {});
 
  /// Checks whether our policies allow us to inline a non-POD type array
  /// construction.
  bool shouldInlineArrayConstruction(const ProgramStateRef State,
                                     const CXXConstructExpr *CE,
                                     const StackFrame *SF);
 
  /// Checks whether our policies allow us to inline a non-POD type array
  /// destruction.
  /// \param Size The size of the array.
  bool shouldInlineArrayDestruction(uint64_t Size);
 
  /// Prepares the program state for array destruction. If no error happens
  /// the function binds a 'PendingArrayDestruction' entry to the state, which
  /// it returns along with the index. If any error happens (we fail to read
  /// the size, the index would be -1, etc.) the function will return the
  /// original state along with an index of 0. The actual element count of the
  /// array can be accessed by the optional 'ElementCountVal' parameter. \param
  /// State The program state. \param Region The memory region where the array
  /// is stored. \param ElementTy The type an element in the array. \param SF
  /// The stack frame. \param ElementCountVal A pointer to an optional SVal.
  /// If specified, the size of the array will be returned in it. It can
  /// be Unknown.
  std::pair<ProgramStateRef, uint64_t> prepareStateForArrayDestruction(
      const ProgramStateRef State, const MemRegion *Region,
      const QualType &ElementTy, const StackFrame *SF,
      SVal *ElementCountVal = nullptr);
 
  /// Checks whether we construct an array of non-POD type, and decides if the
  /// constructor should be invoked once again.
  bool shouldRepeatCtorCall(ProgramStateRef State, const CXXConstructExpr *E,
                            const StackFrame *SF);
 
  void inlineCall(WorkList *WList, const CallEvent &Call, const Decl *D,
                  NodeBuilder &Bldr, ExplodedNode *Pred, ProgramStateRef State);
 
  void ctuBifurcate(const CallEvent &Call, const Decl *D, NodeBuilder &Bldr,
                    ExplodedNode *Pred, ProgramStateRef State);
 
  /// Returns true if the CTU analysis is running its second phase.
  bool isSecondPhaseCTU() { return IsCTUEnabled && !Engine.getCTUWorkList(); }
 
  /// 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 StackFrame *CalleeSF);
 
  /// 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 StackFrame *SF,
      const Expr *InitWithAdjustments, const Expr *Result = nullptr,
      const SubRegion **OutRegionWithAdjustments = nullptr);
 
  /// Returns a region representing the `Idx`th 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 makeElementRegion(ProgramStateRef State, SVal LValue,
                                QualType &Ty, bool &IsArray, unsigned Idx = 0);
 
  /// 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 iterations to model. These methods
  //  are essentially an interface for a GDM trait. Further reading in
  /// ExprEngine::VisitObjCForCollectionStmt().
  [[nodiscard]] static ProgramStateRef
  setWhetherHasMoreIteration(ProgramStateRef State,
                             const ObjCForCollectionStmt *O,
                             const StackFrame *SF, bool HasMoreIteraton);
 
  [[nodiscard]] static ProgramStateRef
  removeIterationState(ProgramStateRef State, const ObjCForCollectionStmt *O,
                       const StackFrame *SF);
 
  [[nodiscard]] static bool hasMoreIteration(ProgramStateRef State,
                                             const ObjCForCollectionStmt *O,
                                             const StackFrame *SF);
 
private:
  /// Assuming we construct an array of non-POD types, this method allows us
  /// to store which element is to be constructed next.
  static ProgramStateRef setIndexOfElementToConstruct(ProgramStateRef State,
                                                      const CXXConstructExpr *E,
                                                      const StackFrame *SF,
                                                      unsigned Idx);
 
  static ProgramStateRef removeIndexOfElementToConstruct(
      ProgramStateRef State, const CXXConstructExpr *E, const StackFrame *SF);
 
  /// Assuming we destruct an array of non-POD types, this method allows us
  /// to store which element is to be destructed next.
  static ProgramStateRef setPendingArrayDestruction(ProgramStateRef State,
                                                    const StackFrame *SF,
                                                    unsigned Idx);
 
  static ProgramStateRef removePendingArrayDestruction(ProgramStateRef State,
                                                       const StackFrame *SF);
 
  /// Sets the size of the array in a pending ArrayInitLoopExpr.
  static ProgramStateRef setPendingInitLoop(ProgramStateRef State,
                                            const CXXConstructExpr *E,
                                            const StackFrame *SF, unsigned Idx);
 
  static ProgramStateRef removePendingInitLoop(ProgramStateRef State,
                                               const CXXConstructExpr *E,
                                               const StackFrame *SF);
 
  static ProgramStateRef removeStateTraitsUsedForArrayEvaluation(
      ProgramStateRef State, const CXXConstructExpr *E, const StackFrame *SF);
 
  /// 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 StackFrame *SF, SVal V);
 
  /// Mark the object as fully constructed, cleaning up the state trait
  /// that tracks objects under construction.
  static ProgramStateRef
  finishObjectConstruction(ProgramStateRef State,
                           const ConstructionContextItem &Item,
                           const StackFrame *SF);
 
  /// 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 StackFrame *SF);
 
  /// Stop tracking the destructor that corresponds to an elided constructor.
  static ProgramStateRef
  cleanupElidedDestructor(ProgramStateRef State,
                          const CXXBindTemporaryExpr *BTE,
                          const StackFrame *SF);
 
  /// 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 StackFrame *SF);
 
  /// Check if all objects under construction have been fully constructed
  /// for the given context range (including FromSF, not including ToSF).
  /// This is useful for assertions. Also checks if elided destructors
  /// were cleaned up.
  static bool areAllObjectsFullyConstructed(ProgramStateRef State,
                                            const StackFrame *FromSF,
                                            const StackFrame *ToSF);
};
 
/// 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