//===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- 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 the C++ expression evaluation engine.

//

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

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

#include "clang/Analysis/ConstructionContext.h"

#include "clang/AST/DeclCXX.h"

#include "clang/AST/StmtCXX.h"

#include "clang/AST/ParentMap.h"

#include "clang/Basic/PrettyStackTrace.h"

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

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

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

using namespace clang;

using namespace ento;

void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,

                                          ExplodedNode *Pred,

                                          ExplodedNodeSet &Dst) {

  StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);

  const Expr *tempExpr = ME->getSubExpr()->IgnoreParens();

  ProgramStateRef state = Pred->getState();

  const LocationContext *LCtx = Pred->getLocationContext();

  state = createTemporaryRegionIfNeeded(state, LCtx, tempExpr, ME);

  Bldr.generateNode(ME, Pred, state);

}

// FIXME: This is the sort of code that should eventually live in a Core

// checker rather than as a special case in ExprEngine.

void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred,

                                    const CallEvent &Call) {

  SVal ThisVal;

  bool AlwaysReturnsLValue;

  const CXXRecordDecl *ThisRD = nullptr;

  if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call)) {

    assert(Ctor->getDecl()->isTrivial());

    assert(Ctor->getDecl()->isCopyOrMoveConstructor());

    ThisVal = Ctor->getCXXThisVal();

    ThisRD = Ctor->getDecl()->getParent();

    AlwaysReturnsLValue = false;

  } else {

    assert(cast<CXXMethodDecl>(Call.getDecl())->isTrivial());

    assert(cast<CXXMethodDecl>(Call.getDecl())->getOverloadedOperator() ==

           OO_Equal);

    ThisVal = cast<CXXInstanceCall>(Call).getCXXThisVal();

    ThisRD = cast<CXXMethodDecl>(Call.getDecl())->getParent();

    AlwaysReturnsLValue = true;

  }

  assert(ThisRD);

  if (ThisRD->isEmpty()) {

    // Do nothing for empty classes. Otherwise it'd retrieve an UnknownVal

    // and bind it and RegionStore would think that the actual value

    // in this region at this offset is unknown.

    return;

  }

  const LocationContext *LCtx = Pred->getLocationContext();

  ExplodedNodeSet Dst;

  Bldr.takeNodes(Pred);

  SVal V = Call.getArgSVal(0);

  // If the value being copied is not unknown, load from its location to get

  // an aggregate rvalue.

  if (Optional<Loc> L = V.getAs<Loc>())

    V = Pred->getState()->getSVal(*L);

  else

    assert(V.isUnknownOrUndef());

  const Expr *CallExpr = Call.getOriginExpr();

  evalBind(Dst, CallExpr, Pred, ThisVal, V, true);

  PostStmt PS(CallExpr, LCtx);

  for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end();

       I != E; 
++I10.9k
) {

    ProgramStateRef State = (*I)->getState();

    if (AlwaysReturnsLValue)

      State = State->BindExpr(CallExpr, LCtx, ThisVal);

    else

      State = bindReturnValue(Call, LCtx, State);

    Bldr.generateNode(PS, State, *I);

  }

}

SVal ExprEngine::makeZeroElementRegion(ProgramStateRef State, SVal LValue,

                                       QualType &Ty, bool &IsArray) {

  SValBuilder &SVB = State->getStateManager().getSValBuilder();

  ASTContext &Ctx = SVB.getContext();

  while (const ArrayType *AT = Ctx.getAsArrayType(Ty)) {

    Ty = AT->getElementType();

    LValue = State->getLValue(Ty, SVB.makeZeroArrayIndex(), LValue);

    IsArray = true;

  }

  return LValue;

}

SVal ExprEngine::computeObjectUnderConstruction(

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

    const ConstructionContext *CC, EvalCallOptions &CallOpts) {

  SValBuilder &SVB = getSValBuilder();

  MemRegionManager &MRMgr = SVB.getRegionManager();

  ASTContext &ACtx = SVB.getContext();

  // Compute the target region by exploring the construction context.

  if (CC) {

    switch (CC->getKind()) {

    case ConstructionContext::CXX17ElidedCopyVariableKind:

    case ConstructionContext::SimpleVariableKind: {

      const auto *DSCC = cast<VariableConstructionContext>(CC);

      const auto *DS = DSCC->getDeclStmt();

      const auto *Var = cast<VarDecl>(DS->getSingleDecl());

      QualType Ty = Var->getType();

      return makeZeroElementRegion(State, State->getLValue(Var, LCtx), Ty,

                                   CallOpts.IsArrayCtorOrDtor);

    }

    case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:

    case ConstructionContext::SimpleConstructorInitializerKind: {

      const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);

      const auto *Init = ICC->getCXXCtorInitializer();

      const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());

      Loc ThisPtr = SVB.getCXXThis(CurCtor, LCtx->getStackFrame());

      SVal ThisVal = State->getSVal(ThisPtr);

      if (Init->isBaseInitializer()) {

        const auto *ThisReg = cast<SubRegion>(ThisVal.getAsRegion());

        const CXXRecordDecl *BaseClass =

          Init->getBaseClass()->getAsCXXRecordDecl();

        const auto *BaseReg =

          MRMgr.getCXXBaseObjectRegion(BaseClass, ThisReg,

                                       Init->isBaseVirtual());

        return SVB.makeLoc(BaseReg);

      }

      if (Init->isDelegatingInitializer())

        return ThisVal;

      const ValueDecl *Field;

      SVal FieldVal;

      if (Init->isIndirectMemberInitializer()) {

        Field = Init->getIndirectMember();

        FieldVal = State->getLValue(Init->getIndirectMember(), ThisVal);

      } else {

        Field = Init->getMember();

        FieldVal = State->getLValue(Init->getMember(), ThisVal);

      }

      QualType Ty = Field->getType();

      return makeZeroElementRegion(State, FieldVal, Ty,

                                   CallOpts.IsArrayCtorOrDtor);

    }

    case ConstructionContext::NewAllocatedObjectKind: {

      if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {

        const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);

        const auto *NE = NECC->getCXXNewExpr();

        SVal V = *getObjectUnderConstruction(State, NE, LCtx);

        if (const SubRegion *MR =

                dyn_cast_or_null<SubRegion>(V.getAsRegion())) {

          if (NE->isArray()) {

            // TODO: In fact, we need to call the constructor for every

            // allocated element, not just the first one!

            CallOpts.IsArrayCtorOrDtor = true;

            return loc::MemRegionVal(getStoreManager().GetElementZeroRegion(

                MR, NE->getType()->getPointeeType()));

          }

          return  V;

        }

        // TODO: Detect when the allocator returns a null pointer.

        // Constructor shall not be called in this case.

      }

      break;

    }

    case ConstructionContext::SimpleReturnedValueKind:

    case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {

      // The temporary is to be managed by the parent stack frame.

      // So build it in the parent stack frame if we're not in the

      // top frame of the analysis.

      const StackFrameContext *SFC = LCtx->getStackFrame();

      if (const LocationContext *CallerLCtx = SFC->getParent()) {

        auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]

                       .getAs<CFGCXXRecordTypedCall>();

        if (!RTC) {

          // We were unable to find the correct construction context for the

          // call in the parent stack frame. This is equivalent to not being

          // able to find construction context at all.

          break;

        }

        if (isa<BlockInvocationContext>(CallerLCtx)) {

          // Unwrap block invocation contexts. They're mostly part of

          // the current stack frame.

          CallerLCtx = CallerLCtx->getParent();

          assert(!isa<BlockInvocationContext>(CallerLCtx));

        }

        return computeObjectUnderConstruction(

            cast<Expr>(SFC->getCallSite()), State, CallerLCtx,

            RTC->getConstructionContext(), CallOpts);

      } else {

        // We are on the top frame of the analysis. We do not know where is the

        // object returned to. Conjure a symbolic region for the return value.

        // TODO: We probably need a new MemRegion kind to represent the storage

        // of that SymbolicRegion, so that we cound produce a fancy symbol

        // instead of an anonymous conjured symbol.

        // TODO: Do we need to track the region to avoid having it dead

        // too early? It does die too early, at least in C++17, but because

        // putting anything into a SymbolicRegion causes an immediate escape,

        // it doesn't cause any leak false positives.

        const auto *RCC = cast<ReturnedValueConstructionContext>(CC);

        // Make sure that this doesn't coincide with any other symbol

        // conjured for the returned expression.

        static const int TopLevelSymRegionTag = 0;

        const Expr *RetE = RCC->getReturnStmt()->getRetValue();

        assert(RetE && "Void returns should not have a construction context");

        QualType ReturnTy = RetE->getType();

        QualType RegionTy = ACtx.getPointerType(ReturnTy);

        return SVB.conjureSymbolVal(&TopLevelSymRegionTag, RetE, SFC, RegionTy,

                                    currBldrCtx->blockCount());

      }

      
llvm_unreachable0
("Unhandled return value construction context!");

    }

    case ConstructionContext::ElidedTemporaryObjectKind: {

      assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);

      const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);

      // Support pre-C++17 copy elision. We'll have the elidable copy

      // constructor in the AST and in the CFG, but we'll skip it

      // and construct directly into the final object. This call

      // also sets the CallOpts flags for us.

      // If the elided copy/move constructor is not supported, there's still

      // benefit in trying to model the non-elided constructor.

      // Stash our state before trying to elide, as it'll get overwritten.

      ProgramStateRef PreElideState = State;

      EvalCallOptions PreElideCallOpts = CallOpts;

      SVal V = computeObjectUnderConstruction(

          TCC->getConstructorAfterElision(), State, LCtx,

          TCC->getConstructionContextAfterElision(), CallOpts);

      // FIXME: This definition of "copy elision has not failed" is unreliable.

      // It doesn't indicate that the constructor will actually be inlined

      // later; this is still up to evalCall() to decide.

      if (!CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion)

        return V;

      // Copy elision failed. Revert the changes and proceed as if we have

      // a simple temporary.

      CallOpts = PreElideCallOpts;

      CallOpts.IsElidableCtorThatHasNotBeenElided = true;

      LLVM_FALLTHROUGH;

    }

    case ConstructionContext::SimpleTemporaryObjectKind: {

      const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);

      const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();

      CallOpts.IsTemporaryCtorOrDtor = true;

      if (MTE) {

        if (const ValueDecl *VD = MTE->getExtendingDecl()) {

          assert(MTE->getStorageDuration() != SD_FullExpression);

          if (!VD->getType()->isReferenceType()) {

            // We're lifetime-extended by a surrounding aggregate.

            // Automatic destructors aren't quite working in this case

            // on the CFG side. We should warn the caller about that.

            // FIXME: Is there a better way to retrieve this information from

            // the MaterializeTemporaryExpr?

            CallOpts.IsTemporaryLifetimeExtendedViaAggregate = true;

          }

        }

        if (MTE->getStorageDuration() == SD_Static ||

            MTE->getStorageDuration() == SD_Thread)

          return loc::MemRegionVal(MRMgr.getCXXStaticTempObjectRegion(E));

      }

      return loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));

    }

    case ConstructionContext::ArgumentKind: {

      // Arguments are technically temporaries.

      CallOpts.IsTemporaryCtorOrDtor = true;

      const auto *ACC = cast<ArgumentConstructionContext>(CC);

      const Expr *E = ACC->getCallLikeExpr();

      unsigned Idx = ACC->getIndex();

      CallEventManager &CEMgr = getStateManager().getCallEventManager();

      auto getArgLoc = [&](CallEventRef<> Caller) -> Optional<SVal> {

        const LocationContext *FutureSFC =

            Caller->getCalleeStackFrame(currBldrCtx->blockCount());

        // Return early if we are unable to reliably foresee

        // the future stack frame.

        if (!FutureSFC)

          return None;

        // This should be equivalent to Caller->getDecl() for now, but

        // FutureSFC->getDecl() is likely to support better stuff (like

        // virtual functions) earlier.

        const Decl *CalleeD = FutureSFC->getDecl();

        // FIXME: Support for variadic arguments is not implemented here yet.

        if (CallEvent::isVariadic(CalleeD))

          return None;

        // Operator arguments do not correspond to operator parameters

        // because this-argument is implemented as a normal argument in

        // operator call expressions but not in operator declarations.

        const TypedValueRegion *TVR = Caller->getParameterLocation(

            *Caller->getAdjustedParameterIndex(Idx), currBldrCtx->blockCount());

        if (!TVR)

          return None;

        return loc::MemRegionVal(TVR);

      };

      if (const auto *CE = dyn_cast<CallExpr>(E)) {

        CallEventRef<> Caller = CEMgr.getSimpleCall(CE, State, LCtx);

        if (Optional<SVal> V = getArgLoc(Caller))

          return *V;

        else

          break;

      } else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {

        // Don't bother figuring out the target region for the future

        // constructor because we won't need it.

        CallEventRef<> Caller =

            CEMgr.getCXXConstructorCall(CCE, /*Target=*/nullptr, State, LCtx);

        if (Optional<SVal> V = getArgLoc(Caller))

          return *V;

        else

          break;

      } else if (const auto *ME = dyn_cast<ObjCMessageExpr>(E)) {

        CallEventRef<> Caller = CEMgr.getObjCMethodCall(ME, State, LCtx);

        if (Optional<SVal> V = getArgLoc(Caller))

          return *V;

        else

          break;

      }

    }

    } // switch (CC->getKind())

  }

  // If we couldn't find an existing region to construct into, assume we're

  // constructing a temporary. Notify the caller of our failure.

  CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;

  return loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));

}

ProgramStateRef ExprEngine::updateObjectsUnderConstruction(

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

    const ConstructionContext *CC, const EvalCallOptions &CallOpts) {

  if (CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) {

    // Sounds like we failed to find the target region and therefore

    // copy elision failed. There's nothing we can do about it here.

    return State;

  }

  // See if we're constructing an existing region by looking at the

  // current construction context.

  assert(CC && "Computed target region without construction context?");

  switch (CC->getKind()) {

  case ConstructionContext::CXX17ElidedCopyVariableKind:

  case ConstructionContext::SimpleVariableKind: {

    const auto *DSCC = cast<VariableConstructionContext>(CC);

    return addObjectUnderConstruction(State, DSCC->getDeclStmt(), LCtx, V);

    }

    case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:

    case ConstructionContext::SimpleConstructorInitializerKind: {

      const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);

      const auto *Init = ICC->getCXXCtorInitializer();

      // Base and delegating initializers handled above

      assert(Init->isAnyMemberInitializer() &&

             "Base and delegating initializers should have been handled by"

             "computeObjectUnderConstruction()");

      return addObjectUnderConstruction(State, Init, LCtx, V);

    }

    case ConstructionContext::NewAllocatedObjectKind: {

      return State;

    }

    case ConstructionContext::SimpleReturnedValueKind:

    case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {

      const StackFrameContext *SFC = LCtx->getStackFrame();

      const LocationContext *CallerLCtx = SFC->getParent();

      if (!CallerLCtx) {

        // No extra work is necessary in top frame.

        return State;

      }

      auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]

                     .getAs<CFGCXXRecordTypedCall>();

      assert(RTC && "Could not have had a target region without it");

      if (isa<BlockInvocationContext>(CallerLCtx)) {

        // Unwrap block invocation contexts. They're mostly part of

        // the current stack frame.

        CallerLCtx = CallerLCtx->getParent();

        assert(!isa<BlockInvocationContext>(CallerLCtx));

      }

      return updateObjectsUnderConstruction(V,

          cast<Expr>(SFC->getCallSite()), State, CallerLCtx,

          RTC->getConstructionContext(), CallOpts);

    }

    case ConstructionContext::ElidedTemporaryObjectKind: {

      assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);

      if (!CallOpts.IsElidableCtorThatHasNotBeenElided) {

        const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);

        State = updateObjectsUnderConstruction(

            V, TCC->getConstructorAfterElision(), State, LCtx,

            TCC->getConstructionContextAfterElision(), CallOpts);

        // Remember that we've elided the constructor.

        State = addObjectUnderConstruction(

            State, TCC->getConstructorAfterElision(), LCtx, V);

        // Remember that we've elided the destructor.

        if (const auto *BTE = TCC->getCXXBindTemporaryExpr())

          State = elideDestructor(State, BTE, LCtx);

        // Instead of materialization, shamelessly return

        // the final object destination.

        if (const auto *MTE = TCC->getMaterializedTemporaryExpr())

          State = addObjectUnderConstruction(State, MTE, LCtx, V);

        return State;

      }

      // If we decided not to elide the constructor, proceed as if

      // it's a simple temporary.

      LLVM_FALLTHROUGH;

    }

    case ConstructionContext::SimpleTemporaryObjectKind: {

      const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);

      if (const auto *BTE = TCC->getCXXBindTemporaryExpr())

        State = addObjectUnderConstruction(State, BTE, LCtx, V);

      if (const auto *MTE = TCC->getMaterializedTemporaryExpr())

        State = addObjectUnderConstruction(State, MTE, LCtx, V);

      return State;

    }

    case ConstructionContext::ArgumentKind: {

      const auto *ACC = cast<ArgumentConstructionContext>(CC);

      if (const auto *BTE = ACC->getCXXBindTemporaryExpr())

        State = addObjectUnderConstruction(State, BTE, LCtx, V);

      return addObjectUnderConstruction(

          State, {ACC->getCallLikeExpr(), ACC->getIndex()}, LCtx, V);

    }

  }

  
llvm_unreachable0
("Unhandled construction context!");

}

void ExprEngine::handleConstructor(const Expr *E,

                                   ExplodedNode *Pred,

                                   ExplodedNodeSet &destNodes) {

  const auto *CE = dyn_cast<CXXConstructExpr>(E);

  const auto *CIE = dyn_cast<CXXInheritedCtorInitExpr>(E);

  assert(CE || CIE);

  const LocationContext *LCtx = Pred->getLocationContext();

  ProgramStateRef State = Pred->getState();

  SVal Target = UnknownVal();

  if (CE) {

    if (Optional<SVal> ElidedTarget =

            getObjectUnderConstruction(State, CE, LCtx)) {

      // We've previously modeled an elidable constructor by pretending that it

      // in fact constructs into the correct target. This constructor can

      // therefore be skipped.

      Target = *ElidedTarget;

      StmtNodeBuilder Bldr(Pred, destNodes, *currBldrCtx);

      State = finishObjectConstruction(State, CE, LCtx);

      if (auto L = Target.getAs<Loc>())

        State = State->BindExpr(CE, LCtx, State->getSVal(*L, CE->getType()));

      Bldr.generateNode(CE, Pred, State);

      return;

    }

  }

  // FIXME: Handle arrays, which run the same constructor for every element.

  // For now, we just run the first constructor (which should still invalidate

  // the entire array).

  EvalCallOptions CallOpts;

  auto C = getCurrentCFGElement().getAs<CFGConstructor>();

  assert(C || getCurrentCFGElement().getAs<CFGStmt>());

  const ConstructionContext *CC = C ? 
C->getConstructionContext()22.7k
 : 
nullptr328
;

  const CXXConstructExpr::ConstructionKind CK =

      CE ? 
CE->getConstructionKind()23.0k
 : 
CIE->getConstructionKind()5
;

  switch (CK) {

  case CXXConstructExpr::CK_Complete: {

    // Inherited constructors are always base class constructors.

    assert(CE && !CIE && "A complete constructor is inherited?!");

    // The target region is found from construction context.

    std::tie(State, Target) =

        handleConstructionContext(CE, State, LCtx, CC, CallOpts);

    break;

  }

  case CXXConstructExpr::CK_VirtualBase: {

    // Make sure we are not calling virtual base class initializers twice.

    // Only the most-derived object should initialize virtual base classes.

    const auto *OuterCtor = dyn_cast_or_null<CXXConstructExpr>(

        LCtx->getStackFrame()->getCallSite());

    assert(

        (!OuterCtor ||

         OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Complete ||

         OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Delegating) &&

        ("This virtual base should have already been initialized by "

         "the most derived class!"));

    (void)OuterCtor;

    LLVM_FALLTHROUGH;

  }

  case CXXConstructExpr::CK_NonVirtualBase:

    // In C++17, classes with non-virtual bases may be aggregates, so they would

    // be initialized as aggregates without a constructor call, so we may have

    // a base class constructed directly into an initializer list without

    // having the derived-class constructor call on the previous stack frame.

    // Initializer lists may be nested into more initializer lists that

    // correspond to surrounding aggregate initializations.

    // FIXME: For now this code essentially bails out. We need to find the

    // correct target region and set it.

    // FIXME: Instead of relying on the ParentMap, we should have the

    // trigger-statement (InitListExpr in this case) passed down from CFG or

    // otherwise always available during construction.

    if (dyn_cast_or_null<InitListExpr>(LCtx->getParentMap().getParent(E))) {

      MemRegionManager &MRMgr = getSValBuilder().getRegionManager();

      Target = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));

      CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;

      break;

    }

    LLVM_FALLTHROUGH;

  case CXXConstructExpr::CK_Delegating: {

    const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());

    Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,

                                              LCtx->getStackFrame());

    SVal ThisVal = State->getSVal(ThisPtr);

    if (CK == CXXConstructExpr::CK_Delegating) {

      Target = ThisVal;

    } else {

      // Cast to the base type.

      bool IsVirtual = (CK == CXXConstructExpr::CK_VirtualBase);

      SVal BaseVal =

          getStoreManager().evalDerivedToBase(ThisVal, E->getType(), IsVirtual);

      Target = BaseVal;

    }

    break;

  }

  }

  if (State != Pred->getState()) {

    static SimpleProgramPointTag T("ExprEngine",

                                   "Prepare for object construction");

    ExplodedNodeSet DstPrepare;

    StmtNodeBuilder BldrPrepare(Pred, DstPrepare, *currBldrCtx);

    BldrPrepare.generateNode(E, Pred, State, &T, ProgramPoint::PreStmtKind);

    assert(DstPrepare.size() <= 1);

    if (DstPrepare.size() == 0)

      return;

    Pred = *BldrPrepare.begin();

  }

  const MemRegion *TargetRegion = Target.getAsRegion();

  CallEventManager &CEMgr = getStateManager().getCallEventManager();

  CallEventRef<> Call =

      CIE ? (CallEventRef<>)CEMgr.getCXXInheritedConstructorCall(

                CIE, TargetRegion, State, LCtx)

          : (CallEventRef<>)CEMgr.getCXXConstructorCall(

                CE, TargetRegion, State, LCtx);

  ExplodedNodeSet DstPreVisit;

  getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, E, *this);

  ExplodedNodeSet PreInitialized;

  if (CE) {

    // FIXME: Is it possible and/or useful to do this before PreStmt?

    StmtNodeBuilder Bldr(DstPreVisit, PreInitialized, *currBldrCtx);

    for (ExplodedNodeSet::iterator I = DstPreVisit.begin(),

                                   E = DstPreVisit.end();

         I != E; 
++I23.0k
) {

      ProgramStateRef State = (*I)->getState();

      if (CE->requiresZeroInitialization()) {

        // FIXME: Once we properly handle constructors in new-expressions, we'll

        // need to invalidate the region before setting a default value, to make

        // sure there aren't any lingering bindings around. This probably needs

        // to happen regardless of whether or not the object is zero-initialized

        // to handle random fields of a placement-initialized object picking up

        // old bindings. We might only want to do it when we need to, though.

        // FIXME: This isn't actually correct for arrays -- we need to zero-

        // initialize the entire array, not just the first element -- but our

        // handling of arrays everywhere else is weak as well, so this shouldn't

        // actually make things worse. Placement new makes this tricky as well,

        // since it's then possible to be initializing one part of a multi-

        // dimensional array.

        State = State->bindDefaultZero(Target, LCtx);

      }

      Bldr.generateNode(CE, *I, State, /*tag=*/nullptr,

                        ProgramPoint::PreStmtKind);

    }

  } else {

    PreInitialized = DstPreVisit;

  }

  ExplodedNodeSet DstPreCall;

  getCheckerManager().runCheckersForPreCall(DstPreCall, PreInitialized,

                                            *Call, *this);

  ExplodedNodeSet DstEvaluated;

  if (CE && 
CE->getConstructor()->isTrivial()23.0k
 &&

      CE->getConstructor()->isCopyOrMoveConstructor() &&

      !CallOpts.IsArrayCtorOrDtor) {

    StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx);

    // FIXME: Handle other kinds of trivial constructors as well.

    for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();

         I != E; 
++I12.5k
)

      performTrivialCopy(Bldr, *I, *Call);

  } else {

    for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();

         I != E; 
++I10.4k
)

      getCheckerManager().runCheckersForEvalCall(DstEvaluated, *I, *Call, *this,

                                                 CallOpts);

  }

  // If the CFG was constructed without elements for temporary destructors

  // and the just-called constructor created a temporary object then

  // stop exploration if the temporary object has a noreturn constructor.

  // This can lose coverage because the destructor, if it were present

  // in the CFG, would be called at the end of the full expression or

  // later (for life-time extended temporaries) -- but avoids infeasible

  // paths when no-return temporary destructors are used for assertions.

  ExplodedNodeSet DstEvaluatedPostProcessed;

  StmtNodeBuilder Bldr(DstEvaluated, DstEvaluatedPostProcessed, *currBldrCtx);

  const AnalysisDeclContext *ADC = LCtx->getAnalysisDeclContext();

  if (!ADC->getCFGBuildOptions().AddTemporaryDtors) {

    if (llvm::isa_and_nonnull<CXXTempObjectRegion>(TargetRegion) &&

        cast<CXXConstructorDecl>(Call->getDecl())

            ->getParent()

            ->isAnyDestructorNoReturn()) {

      // If we've inlined the constructor, then DstEvaluated would be empty.

      // In this case we still want a sink, which could be implemented

      // in processCallExit. But we don't have that implemented at the moment,

      // so if you hit this assertion, see if you can avoid inlining

      // the respective constructor when analyzer-config cfg-temporary-dtors

      // is set to false.

      // Otherwise there's nothing wrong with inlining such constructor.

      assert(!DstEvaluated.empty() &&

             "We should not have inlined this constructor!");

      for (ExplodedNode *N : DstEvaluated) {

        Bldr.generateSink(E, N, N->getState());

      }

      // There is no need to run the PostCall and PostStmt checker

      // callbacks because we just generated sinks on all nodes in th

      // frontier.

      return;

    }

  }

  ExplodedNodeSet DstPostArgumentCleanup;

  for (ExplodedNode *I : DstEvaluatedPostProcessed)

    finishArgumentConstruction(DstPostArgumentCleanup, I, *Call);

  // If there were other constructors called for object-type arguments

  // of this constructor, clean them up.

  ExplodedNodeSet DstPostCall;

  getCheckerManager().runCheckersForPostCall(DstPostCall,

                                             DstPostArgumentCleanup,

                                             *Call, *this);

  getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, E, *this);

}

void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE,

                                       ExplodedNode *Pred,

                                       ExplodedNodeSet &Dst) {

  handleConstructor(CE, Pred, Dst);

}

void ExprEngine::VisitCXXInheritedCtorInitExpr(

    const CXXInheritedCtorInitExpr *CE, ExplodedNode *Pred,

    ExplodedNodeSet &Dst) {

  handleConstructor(CE, Pred, Dst);

}

void ExprEngine::VisitCXXDestructor(QualType ObjectType,

                                    const MemRegion *Dest,

                                    const Stmt *S,

                                    bool IsBaseDtor,

                                    ExplodedNode *Pred,

                                    ExplodedNodeSet &Dst,

                                    EvalCallOptions &CallOpts) {

  assert(S && "A destructor without a trigger!");

  const LocationContext *LCtx = Pred->getLocationContext();

  ProgramStateRef State = Pred->getState();

  const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl();

  assert(RecordDecl && "Only CXXRecordDecls should have destructors");

  const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor();

  // FIXME: There should always be a Decl, otherwise the destructor call

  // shouldn't have been added to the CFG in the first place.

  if (!DtorDecl) {

    // Skip the invalid destructor. We cannot simply return because

    // it would interrupt the analysis instead.

    static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");

    // FIXME: PostImplicitCall with a null decl may crash elsewhere anyway.

    PostImplicitCall PP(/*Decl=*/nullptr, S->getEndLoc(), LCtx, &T);

    NodeBuilder Bldr(Pred, Dst, *currBldrCtx);

    Bldr.generateNode(PP, Pred->getState(), Pred);

    return;

  }

  if (!Dest) {

    // We're trying to destroy something that is not a region. This may happen

    // for a variety of reasons (unknown target region, concrete integer instead

    // of target region, etc.). The current code makes an attempt to recover.

    // FIXME: We probably don't really need to recover when we're dealing

    // with concrete integers specifically.

    CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;

    if (const Expr *E = dyn_cast_or_null<Expr>(S)) {

      Dest = MRMgr.getCXXTempObjectRegion(E, Pred->getLocationContext());

    } else {

      static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");

      NodeBuilder Bldr(Pred, Dst, *currBldrCtx);

      Bldr.generateSink(Pred->getLocation().withTag(&T),

                        Pred->getState(), Pred);

      return;

    }

  }

  CallEventManager &CEMgr = getStateManager().getCallEventManager();

  CallEventRef<CXXDestructorCall> Call =

      CEMgr.getCXXDestructorCall(DtorDecl, S, Dest, IsBaseDtor, State, LCtx);

  PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),

                                Call->getSourceRange().getBegin(),

                                "Error evaluating destructor");

  ExplodedNodeSet DstPreCall;

  getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,

                                            *Call, *this);

  ExplodedNodeSet DstInvalidated;

  StmtNodeBuilder Bldr(DstPreCall, DstInvalidated, *currBldrCtx);

  for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();

       I != E; 
++I1.49k
)

    defaultEvalCall(Bldr, *I, *Call, CallOpts);

  getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated,

                                             *Call, *this);

}

void ExprEngine::VisitCXXNewAllocatorCall(const CXXNewExpr *CNE,

                                          ExplodedNode *Pred,

                                          ExplodedNodeSet &Dst) {

  ProgramStateRef State = Pred->getState();

  const LocationContext *LCtx = Pred->getLocationContext();

  PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),

                                CNE->getBeginLoc(),

                                "Error evaluating New Allocator Call");

  CallEventManager &CEMgr = getStateManager().getCallEventManager();

  CallEventRef<CXXAllocatorCall> Call =

    CEMgr.getCXXAllocatorCall(CNE, State, LCtx);

  ExplodedNodeSet DstPreCall;

  getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,

                                            *Call, *this);

  ExplodedNodeSet DstPostCall;

  StmtNodeBuilder CallBldr(DstPreCall, DstPostCall, *currBldrCtx);

  for (ExplodedNode *I : DstPreCall) {

    // FIXME: Provide evalCall for checkers?

    defaultEvalCall(CallBldr, I, *Call);

  }

  // If the call is inlined, DstPostCall will be empty and we bail out now.

  // Store return value of operator new() for future use, until the actual

  // CXXNewExpr gets processed.

  ExplodedNodeSet DstPostValue;

  StmtNodeBuilder ValueBldr(DstPostCall, DstPostValue, *currBldrCtx);

  for (ExplodedNode *I : DstPostCall) {

    // FIXME: Because CNE serves as the "call site" for the allocator (due to

    // lack of a better expression in the AST), the conjured return value symbol

    // is going to be of the same type (C++ object pointer type). Technically

    // this is not correct because the operator new's prototype always says that

    // it returns a 'void *'. So we should change the type of the symbol,

    // and then evaluate the cast over the symbolic pointer from 'void *' to

    // the object pointer type. But without changing the symbol's type it

    // is breaking too much to evaluate the no-op symbolic cast over it, so we

    // skip it for now.

    ProgramStateRef State = I->getState();

    SVal RetVal = State->getSVal(CNE, LCtx);

    // If this allocation function is not declared as non-throwing, failures

    // /must/ be signalled by exceptions, and thus the return value will never

    // be NULL. -fno-exceptions does not influence this semantics.

    // FIXME: GCC has a -fcheck-new option, which forces it to consider the case

    // where new can return NULL. If we end up supporting that option, we can

    // consider adding a check for it here.

    // C++11 [basic.stc.dynamic.allocation]p3.

    if (const FunctionDecl *FD = CNE->getOperatorNew()) {

      QualType Ty = FD->getType();

      if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())

        if (!ProtoType->isNothrow())

          State = State->assume(RetVal.castAs<DefinedOrUnknownSVal>(), true);

    }

    ValueBldr.generateNode(

        CNE, I, addObjectUnderConstruction(State, CNE, LCtx, RetVal));

  }

  ExplodedNodeSet DstPostPostCallCallback;

  getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback,

                                             DstPostValue, *Call, *this);

  for (ExplodedNode *I : DstPostPostCallCallback) {

    getCheckerManager().runCheckersForNewAllocator(*Call, Dst, I, *this);

  }

}

void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,

                                   ExplodedNodeSet &Dst) {

  // FIXME: Much of this should eventually migrate to CXXAllocatorCall.

  // Also, we need to decide how allocators actually work -- they're not

  // really part of the CXXNewExpr because they happen BEFORE the

  // CXXConstructExpr subexpression. See PR12014 for some discussion.

  unsigned blockCount = currBldrCtx->blockCount();

  const LocationContext *LCtx = Pred->getLocationContext();

  SVal symVal = UnknownVal();

  FunctionDecl *FD = CNE->getOperatorNew();

  bool IsStandardGlobalOpNewFunction =

      FD->isReplaceableGlobalAllocationFunction();

  ProgramStateRef State = Pred->getState();

  // Retrieve the stored operator new() return value.

  if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {

    symVal = *getObjectUnderConstruction(State, CNE, LCtx);

    State = finishObjectConstruction(State, CNE, LCtx);

  }

  // We assume all standard global 'operator new' functions allocate memory in

  // heap. We realize this is an approximation that might not correctly model

  // a custom global allocator.

  if (symVal.isUnknown()) {

    if (IsStandardGlobalOpNewFunction)

      symVal = svalBuilder.getConjuredHeapSymbolVal(CNE, LCtx, blockCount);

    else

      symVal = svalBuilder.conjureSymbolVal(nullptr, CNE, LCtx, CNE->getType(),

                                            blockCount);

  }

  CallEventManager &CEMgr = getStateManager().getCallEventManager();

  CallEventRef<CXXAllocatorCall> Call =

    CEMgr.getCXXAllocatorCall(CNE, State, LCtx);

  if (!AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {

    // Invalidate placement args.

    // FIXME: Once we figure out how we want allocators to work,

    // we should be using the usual pre-/(default-)eval-/post-call checkers

    // here.

    State = Call->invalidateRegions(blockCount);

    if (!State)

      return;

    // If this allocation function is not declared as non-throwing, failures

    // /must/ be signalled by exceptions, and thus the return value will never

    // be NULL. -fno-exceptions does not influence this semantics.

    // FIXME: GCC has a -fcheck-new option, which forces it to consider the case

    // where new can return NULL. If we end up supporting that option, we can

    // consider adding a check for it here.

    // C++11 [basic.stc.dynamic.allocation]p3.

    if (FD) {

      QualType Ty = FD->getType();

      if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())

        if (!ProtoType->isNothrow())

          if (auto dSymVal = symVal.getAs<DefinedOrUnknownSVal>())

            State = State->assume(*dSymVal, true);

    }

  }

  StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);

  SVal Result = symVal;

  if (CNE->isArray()) {

    // FIXME: allocating an array requires simulating the constructors.

    // For now, just return a symbolicated region.

    if (const auto *NewReg = cast_or_null<SubRegion>(symVal.getAsRegion())) {

      QualType ObjTy = CNE->getType()->getPointeeType();

      const ElementRegion *EleReg =

          getStoreManager().GetElementZeroRegion(NewReg, ObjTy);

      Result = loc::MemRegionVal(EleReg);

    }

    State = State->BindExpr(CNE, Pred->getLocationContext(), Result);

    Bldr.generateNode(CNE, Pred, State);

    return;

  }

  // FIXME: Once we have proper support for CXXConstructExprs inside

  // CXXNewExpr, we need to make sure that the constructed object is not

  // immediately invalidated here. (The placement call should happen before

  // the constructor call anyway.)

  if (FD && FD->isReservedGlobalPlacementOperator()) {

    // Non-array placement new should always return the placement location.

    SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx);

    Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(),

                                  CNE->getPlacementArg(0)->getType());

  }

  // Bind the address of the object, then check to see if we cached out.

  State = State->BindExpr(CNE, LCtx, Result);

  ExplodedNode *NewN = Bldr.generateNode(CNE, Pred, State);

  if (!NewN)

    return;

  // If the type is not a record, we won't have a CXXConstructExpr as an

  // initializer. Copy the value over.

  if (const Expr *Init = CNE->getInitializer()) {

    if (!isa<CXXConstructExpr>(Init)) {

      assert(Bldr.getResults().size() == 1);

      Bldr.takeNodes(NewN);

      evalBind(Dst, CNE, NewN, Result, State->getSVal(Init, LCtx),

               /*FirstInit=*/IsStandardGlobalOpNewFunction);

    }

  }

}

void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE,

                                    ExplodedNode *Pred, ExplodedNodeSet &Dst) {

  CallEventManager &CEMgr = getStateManager().getCallEventManager();

  CallEventRef<CXXDeallocatorCall> Call = CEMgr.getCXXDeallocatorCall(

      CDE, Pred->getState(), Pred->getLocationContext());

  ExplodedNodeSet DstPreCall;

  getCheckerManager().runCheckersForPreCall(DstPreCall, Pred, *Call, *this);

  getCheckerManager().runCheckersForPostCall(Dst, DstPreCall, *Call, *this);

}

void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS, ExplodedNode *Pred,

                                   ExplodedNodeSet &Dst) {

  const VarDecl *VD = CS->getExceptionDecl();

  if (!VD) {

    Dst.Add(Pred);

    return;

  }

  const LocationContext *LCtx = Pred->getLocationContext();

  SVal V = svalBuilder.conjureSymbolVal(CS, LCtx, VD->getType(),

                                        currBldrCtx->blockCount());

  ProgramStateRef state = Pred->getState();

  state = state->bindLoc(state->getLValue(VD, LCtx), V, LCtx);

  StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);

  Bldr.generateNode(CS, Pred, state);

}

void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,

                                    ExplodedNodeSet &Dst) {

  StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);

  // Get the this object region from StoreManager.

  const LocationContext *LCtx = Pred->getLocationContext();

  const MemRegion *R =

    svalBuilder.getRegionManager().getCXXThisRegion(

                                  getContext().getCanonicalType(TE->getType()),

                                                    LCtx);

  ProgramStateRef state = Pred->getState();

  SVal V = state->getSVal(loc::MemRegionVal(R));

  Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V));

}

void ExprEngine::VisitLambdaExpr(const LambdaExpr *LE, ExplodedNode *Pred,

                                 ExplodedNodeSet &Dst) {

  const LocationContext *LocCtxt = Pred->getLocationContext();

  // Get the region of the lambda itself.

  const MemRegion *R = svalBuilder.getRegionManager().getCXXTempObjectRegion(

      LE, LocCtxt);

  SVal V = loc::MemRegionVal(R);

  ProgramStateRef State = Pred->getState();

  // If we created a new MemRegion for the lambda, we should explicitly bind

  // the captures.

  CXXRecordDecl::field_iterator CurField = LE->getLambdaClass()->field_begin();

  for (LambdaExpr::const_capture_init_iterator i = LE->capture_init_begin(),

                                               e = LE->capture_init_end();

       i != e; 
++i, ++CurField201
) {

    FieldDecl *FieldForCapture = *CurField;

    SVal FieldLoc = State->getLValue(FieldForCapture, V);

    SVal InitVal;

    if (!FieldForCapture->hasCapturedVLAType()) {

      Expr *InitExpr = *i;

      assert(InitExpr && "Capture missing initialization expression");

      InitVal = State->getSVal(InitExpr, LocCtxt);

    } else {

      // The field stores the length of a captured variable-length array.

      // These captures don't have initialization expressions; instead we

      // get the length from the VLAType size expression.

      Expr *SizeExpr = FieldForCapture->getCapturedVLAType()->getSizeExpr();

      InitVal = State->getSVal(SizeExpr, LocCtxt);

    }

    State = State->bindLoc(FieldLoc, InitVal, LocCtxt);

  }

  // Decay the Loc into an RValue, because there might be a

  // MaterializeTemporaryExpr node above this one which expects the bound value

  // to be an RValue.

  SVal LambdaRVal = State->getSVal(R);

  ExplodedNodeSet Tmp;

  StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);

  // FIXME: is this the right program point kind?

  Bldr.generateNode(LE, Pred,

                    State->BindExpr(LE, LocCtxt, LambdaRVal),

                    nullptr, ProgramPoint::PostLValueKind);

  // FIXME: Move all post/pre visits to ::Visit().