SemaOpenMP.cpp

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//===--- SemaOpenMP.cpp - Semantic Analysis for OpenMP constructs ---------===//
//
// 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements semantic analysis for OpenMP directives and
/// clauses.
///
//===----------------------------------------------------------------------===//
 
#include "TreeTransform.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclOpenMP.h"
#include "clang/AST/OpenMPClause.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtOpenMP.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/TypeOrdering.h"
#include "clang/Basic/DiagnosticSema.h"
#include "clang/Basic/OpenMPKinds.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/PointerEmbeddedInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Frontend/OpenMP/OMPAssume.h"
#include "llvm/Frontend/OpenMP/OMPConstants.h"
#include <set>
 
using namespace clang;
using namespace llvm::omp;
 
//===----------------------------------------------------------------------===//
// Stack of data-sharing attributes for variables
//===----------------------------------------------------------------------===//
 
static const Expr *checkMapClauseExpressionBase(
    Sema &SemaRef, Expr *E,
    OMPClauseMappableExprCommon::MappableExprComponentList &CurComponents,
    OpenMPClauseKind CKind, OpenMPDirectiveKind DKind, bool NoDiagnose);
 
namespace {
/// Default data sharing attributes, which can be applied to directive.
enum DefaultDataSharingAttributes {
  DSA_unspecified = 0,       /// Data sharing attribute not specified.
  DSA_none = 1 << 0,         /// Default data sharing attribute 'none'.
  DSA_shared = 1 << 1,       /// Default data sharing attribute 'shared'.
  DSA_private = 1 << 2,      /// Default data sharing attribute 'private'.
  DSA_firstprivate = 1 << 3, /// Default data sharing attribute 'firstprivate'.
};
 
/// Stack for tracking declarations used in OpenMP directives and
/// clauses and their data-sharing attributes.
class DSAStackTy {
public:
  struct DSAVarData {
    OpenMPDirectiveKind DKind = OMPD_unknown;
    OpenMPClauseKind CKind = OMPC_unknown;
    unsigned Modifier = 0;
    const Expr *RefExpr = nullptr;
    DeclRefExpr *PrivateCopy = nullptr;
    SourceLocation ImplicitDSALoc;
    bool AppliedToPointee = false;
    DSAVarData() = default;
    DSAVarData(OpenMPDirectiveKind DKind, OpenMPClauseKind CKind,
               const Expr *RefExpr, DeclRefExpr *PrivateCopy,
               SourceLocation ImplicitDSALoc, unsigned Modifier,
               bool AppliedToPointee)
        : DKind(DKind), CKind(CKind), Modifier(Modifier), RefExpr(RefExpr),
          PrivateCopy(PrivateCopy), ImplicitDSALoc(ImplicitDSALoc),
          AppliedToPointee(AppliedToPointee) {}
  };
  using OperatorOffsetTy =
      llvm::SmallVector<std::pair<Expr *, OverloadedOperatorKind>, 4>;
  using DoacrossDependMapTy =
      llvm::DenseMap<OMPDependClause *, OperatorOffsetTy>;
  /// Kind of the declaration used in the uses_allocators clauses.
  enum class UsesAllocatorsDeclKind {
    /// Predefined allocator
    PredefinedAllocator,
    /// User-defined allocator
    UserDefinedAllocator,
    /// The declaration that represent allocator trait
    AllocatorTrait,
  };
 
private:
  struct DSAInfo {
    OpenMPClauseKind Attributes = OMPC_unknown;
    unsigned Modifier = 0;
    /// Pointer to a reference expression and a flag which shows that the
    /// variable is marked as lastprivate(true) or not (false).
    llvm::PointerIntPair<const Expr *, 1, bool> RefExpr;
    DeclRefExpr *PrivateCopy = nullptr;
    /// true if the attribute is applied to the pointee, not the variable
    /// itself.
    bool AppliedToPointee = false;
  };
  using DeclSAMapTy = llvm::SmallDenseMap<const ValueDecl *, DSAInfo, 8>;
  using UsedRefMapTy = llvm::SmallDenseMap<const ValueDecl *, const Expr *, 8>;
  using LCDeclInfo = std::pair<unsigned, VarDecl *>;
  using LoopControlVariablesMapTy =
      llvm::SmallDenseMap<const ValueDecl *, LCDeclInfo, 8>;
  /// Struct that associates a component with the clause kind where they are
  /// found.
  struct MappedExprComponentTy {
    OMPClauseMappableExprCommon::MappableExprComponentLists Components;
    OpenMPClauseKind Kind = OMPC_unknown;
  };
  using MappedExprComponentsTy =
      llvm::DenseMap<const ValueDecl *, MappedExprComponentTy>;
  using CriticalsWithHintsTy =
      llvm::StringMap<std::pair<const OMPCriticalDirective *, llvm::APSInt>>;
  struct ReductionData {
    using BOKPtrType = llvm::PointerEmbeddedInt<BinaryOperatorKind, 16>;
    SourceRange ReductionRange;
    llvm::PointerUnion<const Expr *, BOKPtrType> ReductionOp;
    ReductionData() = default;
    void set(BinaryOperatorKind BO, SourceRange RR) {
      ReductionRange = RR;
      ReductionOp = BO;
    }
    void set(const Expr *RefExpr, SourceRange RR) {
      ReductionRange = RR;
      ReductionOp = RefExpr;
    }
  };
  using DeclReductionMapTy =
      llvm::SmallDenseMap<const ValueDecl *, ReductionData, 4>;
  struct DefaultmapInfo {
    OpenMPDefaultmapClauseModifier ImplicitBehavior =
        OMPC_DEFAULTMAP_MODIFIER_unknown;
    SourceLocation SLoc;
    DefaultmapInfo() = default;
    DefaultmapInfo(OpenMPDefaultmapClauseModifier M, SourceLocation Loc)
        : ImplicitBehavior(M), SLoc(Loc) {}
  };
 
  struct SharingMapTy {
    DeclSAMapTy SharingMap;
    DeclReductionMapTy ReductionMap;
    UsedRefMapTy AlignedMap;
    UsedRefMapTy NontemporalMap;
    MappedExprComponentsTy MappedExprComponents;
    LoopControlVariablesMapTy LCVMap;
    DefaultDataSharingAttributes DefaultAttr = DSA_unspecified;
    SourceLocation DefaultAttrLoc;
    DefaultmapInfo DefaultmapMap[OMPC_DEFAULTMAP_unknown];
    OpenMPDirectiveKind Directive = OMPD_unknown;
    DeclarationNameInfo DirectiveName;
    Scope *CurScope = nullptr;
    DeclContext *Context = nullptr;
    SourceLocation ConstructLoc;
    /// Set of 'depend' clauses with 'sink|source' dependence kind. Required to
    /// get the data (loop counters etc.) about enclosing loop-based construct.
    /// This data is required during codegen.
    DoacrossDependMapTy DoacrossDepends;
    /// First argument (Expr *) contains optional argument of the
    /// 'ordered' clause, the second one is true if the regions has 'ordered'
    /// clause, false otherwise.
    llvm::Optional<std::pair<const Expr *, OMPOrderedClause *>> OrderedRegion;
    unsigned AssociatedLoops = 1;
    bool HasMutipleLoops = false;
    const Decl *PossiblyLoopCounter = nullptr;
    bool NowaitRegion = false;
    bool UntiedRegion = false;
    bool CancelRegion = false;
    bool LoopStart = false;
    bool BodyComplete = false;
    SourceLocation PrevScanLocation;
    SourceLocation PrevOrderedLocation;
    SourceLocation InnerTeamsRegionLoc;
    /// Reference to the taskgroup task_reduction reference expression.
    Expr *TaskgroupReductionRef = nullptr;
    llvm::DenseSet<QualType> MappedClassesQualTypes;
    SmallVector<Expr *, 4> InnerUsedAllocators;
    llvm::DenseSet<CanonicalDeclPtr<Decl>> ImplicitTaskFirstprivates;
    /// List of globals marked as declare target link in this target region
    /// (isOpenMPTargetExecutionDirective(Directive) == true).
    llvm::SmallVector<DeclRefExpr *, 4> DeclareTargetLinkVarDecls;
    /// List of decls used in inclusive/exclusive clauses of the scan directive.
    llvm::DenseSet<CanonicalDeclPtr<Decl>> UsedInScanDirective;
    llvm::DenseMap<CanonicalDeclPtr<const Decl>, UsesAllocatorsDeclKind>
        UsesAllocatorsDecls;
    /// Data is required on creating capture fields for implicit
    /// default first|private clause.
    struct ImplicitDefaultFDInfoTy {
      /// Field decl.
      const FieldDecl *FD = nullptr;
      /// Nesting stack level
      size_t StackLevel = 0;
      /// Capture variable decl.
      VarDecl *VD = nullptr;
      ImplicitDefaultFDInfoTy(const FieldDecl *FD, size_t StackLevel,
                              VarDecl *VD)
          : FD(FD), StackLevel(StackLevel), VD(VD) {}
    };
    /// List of captured fields
    llvm::SmallVector<ImplicitDefaultFDInfoTy, 8>
        ImplicitDefaultFirstprivateFDs;
    Expr *DeclareMapperVar = nullptr;
    SharingMapTy(OpenMPDirectiveKind DKind, DeclarationNameInfo Name,
                 Scope *CurScope, SourceLocation Loc)
        : Directive(DKind), DirectiveName(Name), CurScope(CurScope),
          ConstructLoc(Loc) {}
    SharingMapTy() = default;
  };
 
  using StackTy = SmallVector<SharingMapTy, 4>;
 
  /// Stack of used declaration and their data-sharing attributes.
  DeclSAMapTy Threadprivates;
  const FunctionScopeInfo *CurrentNonCapturingFunctionScope = nullptr;
  SmallVector<std::pair<StackTy, const FunctionScopeInfo *>, 4> Stack;
  /// true, if check for DSA must be from parent directive, false, if
  /// from current directive.
  OpenMPClauseKind ClauseKindMode = OMPC_unknown;
  Sema &SemaRef;
  bool ForceCapturing = false;
  /// true if all the variables in the target executable directives must be
  /// captured by reference.
  bool ForceCaptureByReferenceInTargetExecutable = false;
  CriticalsWithHintsTy Criticals;
  unsigned IgnoredStackElements = 0;
 
  /// Iterators over the stack iterate in order from innermost to outermost
  /// directive.
  using const_iterator = StackTy::const_reverse_iterator;
  const_iterator begin() const {
    return Stack.empty() ? const_iterator()
                         : Stack.back().first.rbegin() + IgnoredStackElements;
  }
  const_iterator end() const {
    return Stack.empty() ? const_iterator() : Stack.back().first.rend();
  }
  using iterator = StackTy::reverse_iterator;
  iterator begin() {
    return Stack.empty() ? iterator()
                         : Stack.back().first.rbegin() + IgnoredStackElements;
  }
  iterator end() {
    return Stack.empty() ? iterator() : Stack.back().first.rend();
  }
 
  // Convenience operations to get at the elements of the stack.
 
  bool isStackEmpty() const {
    return Stack.empty() ||
           Stack.back().second != CurrentNonCapturingFunctionScope ||
           Stack.back().first.size() <= IgnoredStackElements;
  }
  size_t getStackSize() const {
    return isStackEmpty() ? 0
                          : Stack.back().first.size() - IgnoredStackElements;
  }
 
  SharingMapTy *getTopOfStackOrNull() {
    size_t Size = getStackSize();
    if (Size == 0)
      return nullptr;
    return &Stack.back().first[Size - 1];
  }
  const SharingMapTy *getTopOfStackOrNull() const {
    return const_cast<DSAStackTy &>(*this).getTopOfStackOrNull();
  }
  SharingMapTy &getTopOfStack() {
    assert(!isStackEmpty() && "no current directive");
    return *getTopOfStackOrNull();
  }
  const SharingMapTy &getTopOfStack() const {
    return const_cast<DSAStackTy &>(*this).getTopOfStack();
  }
 
  SharingMapTy *getSecondOnStackOrNull() {
    size_t Size = getStackSize();
    if (Size <= 1)
      return nullptr;
    return &Stack.back().first[Size - 2];
  }
  const SharingMapTy *getSecondOnStackOrNull() const {
    return const_cast<DSAStackTy &>(*this).getSecondOnStackOrNull();
  }
 
  /// Get the stack element at a certain level (previously returned by
  /// \c getNestingLevel).
  ///
  /// Note that nesting levels count from outermost to innermost, and this is
  /// the reverse of our iteration order where new inner levels are pushed at
  /// the front of the stack.
  SharingMapTy &getStackElemAtLevel(unsigned Level) {
    assert(Level < getStackSize() && "no such stack element");
    return Stack.back().first[Level];
  }
  const SharingMapTy &getStackElemAtLevel(unsigned Level) const {
    return const_cast<DSAStackTy &>(*this).getStackElemAtLevel(Level);
  }
 
  DSAVarData getDSA(const_iterator &Iter, ValueDecl *D) const;
 
  /// Checks if the variable is a local for OpenMP region.
  bool isOpenMPLocal(VarDecl *D, const_iterator Iter) const;
 
  /// Vector of previously declared requires directives
  SmallVector<const OMPRequiresDecl *, 2> RequiresDecls;
  /// omp_allocator_handle_t type.
  QualType OMPAllocatorHandleT;
  /// omp_depend_t type.
  QualType OMPDependT;
  /// omp_event_handle_t type.
  QualType OMPEventHandleT;
  /// omp_alloctrait_t type.
  QualType OMPAlloctraitT;
  /// Expression for the predefined allocators.
  Expr *OMPPredefinedAllocators[OMPAllocateDeclAttr::OMPUserDefinedMemAlloc] = {
      nullptr};
  /// Vector of previously encountered target directives
  SmallVector<SourceLocation, 2> TargetLocations;
  SourceLocation AtomicLocation;
  /// Vector of declare variant construct traits.
  SmallVector<llvm::omp::TraitProperty, 8> ConstructTraits;
 
public:
  explicit DSAStackTy(Sema &S) : SemaRef(S) {}
 
  /// Sets omp_allocator_handle_t type.
  void setOMPAllocatorHandleT(QualType Ty) { OMPAllocatorHandleT = Ty; }
  /// Gets omp_allocator_handle_t type.
  QualType getOMPAllocatorHandleT() const { return OMPAllocatorHandleT; }
  /// Sets omp_alloctrait_t type.
  void setOMPAlloctraitT(QualType Ty) { OMPAlloctraitT = Ty; }
  /// Gets omp_alloctrait_t type.
  QualType getOMPAlloctraitT() const { return OMPAlloctraitT; }
  /// Sets the given default allocator.
  void setAllocator(OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind,
                    Expr *Allocator) {
    OMPPredefinedAllocators[AllocatorKind] = Allocator;
  }
  /// Returns the specified default allocator.
  Expr *getAllocator(OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind) const {
    return OMPPredefinedAllocators[AllocatorKind];
  }
  /// Sets omp_depend_t type.
  void setOMPDependT(QualType Ty) { OMPDependT = Ty; }
  /// Gets omp_depend_t type.
  QualType getOMPDependT() const { return OMPDependT; }
 
  /// Sets omp_event_handle_t type.
  void setOMPEventHandleT(QualType Ty) { OMPEventHandleT = Ty; }
  /// Gets omp_event_handle_t type.
  QualType getOMPEventHandleT() const { return OMPEventHandleT; }
 
  bool isClauseParsingMode() const { return ClauseKindMode != OMPC_unknown; }
  OpenMPClauseKind getClauseParsingMode() const {
    assert(isClauseParsingMode() && "Must be in clause parsing mode.");
    return ClauseKindMode;
  }
  void setClauseParsingMode(OpenMPClauseKind K) { ClauseKindMode = K; }
 
  bool isBodyComplete() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top && Top->BodyComplete;
  }
  void setBodyComplete() { getTopOfStack().BodyComplete = true; }
 
  bool isForceVarCapturing() const { return ForceCapturing; }
  void setForceVarCapturing(bool V) { ForceCapturing = V; }
 
  void setForceCaptureByReferenceInTargetExecutable(bool V) {
    ForceCaptureByReferenceInTargetExecutable = V;
  }
  bool isForceCaptureByReferenceInTargetExecutable() const {
    return ForceCaptureByReferenceInTargetExecutable;
  }
 
  void push(OpenMPDirectiveKind DKind, const DeclarationNameInfo &DirName,
            Scope *CurScope, SourceLocation Loc) {
    assert(!IgnoredStackElements &&
           "cannot change stack while ignoring elements");
    if (Stack.empty() ||
        Stack.back().second != CurrentNonCapturingFunctionScope)
      Stack.emplace_back(StackTy(), CurrentNonCapturingFunctionScope);
    Stack.back().first.emplace_back(DKind, DirName, CurScope, Loc);
    Stack.back().first.back().DefaultAttrLoc = Loc;
  }
 
  void pop() {
    assert(!IgnoredStackElements &&
           "cannot change stack while ignoring elements");
    assert(!Stack.back().first.empty() &&
           "Data-sharing attributes stack is empty!");
    Stack.back().first.pop_back();
  }
 
  /// RAII object to temporarily leave the scope of a directive when we want to
  /// logically operate in its parent.
  class ParentDirectiveScope {
    DSAStackTy &Self;
    bool Active;
 
  public:
    ParentDirectiveScope(DSAStackTy &Self, bool Activate)
        : Self(Self), Active(false) {
      if (Activate)
        enable();
    }
    ~ParentDirectiveScope() { disable(); }
    void disable() {
      if (Active) {
        --Self.IgnoredStackElements;
        Active = false;
      }
    }
    void enable() {
      if (!Active) {
        ++Self.IgnoredStackElements;
        Active = true;
      }
    }
  };
 
  /// Marks that we're started loop parsing.
  void loopInit() {
    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
           "Expected loop-based directive.");
    getTopOfStack().LoopStart = true;
  }
  /// Start capturing of the variables in the loop context.
  void loopStart() {
    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
           "Expected loop-based directive.");
    getTopOfStack().LoopStart = false;
  }
  /// true, if variables are captured, false otherwise.
  bool isLoopStarted() const {
    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
           "Expected loop-based directive.");
    return !getTopOfStack().LoopStart;
  }
  /// Marks (or clears) declaration as possibly loop counter.
  void resetPossibleLoopCounter(const Decl *D = nullptr) {
    getTopOfStack().PossiblyLoopCounter = D ? D->getCanonicalDecl() : D;
  }
  /// Gets the possible loop counter decl.
  const Decl *getPossiblyLoopCunter() const {
    return getTopOfStack().PossiblyLoopCounter;
  }
  /// Start new OpenMP region stack in new non-capturing function.
  void pushFunction() {
    assert(!IgnoredStackElements &&
           "cannot change stack while ignoring elements");
    const FunctionScopeInfo *CurFnScope = SemaRef.getCurFunction();
    assert(!isa<CapturingScopeInfo>(CurFnScope));
    CurrentNonCapturingFunctionScope = CurFnScope;
  }
  /// Pop region stack for non-capturing function.
  void popFunction(const FunctionScopeInfo *OldFSI) {
    assert(!IgnoredStackElements &&
           "cannot change stack while ignoring elements");
    if (!Stack.empty() && Stack.back().second == OldFSI) {
      assert(Stack.back().first.empty());
      Stack.pop_back();
    }
    CurrentNonCapturingFunctionScope = nullptr;
    for (const FunctionScopeInfo *FSI : llvm::reverse(SemaRef.FunctionScopes)) {
      if (!isa<CapturingScopeInfo>(FSI)) {
        CurrentNonCapturingFunctionScope = FSI;
        break;
      }
    }
  }
 
  void addCriticalWithHint(const OMPCriticalDirective *D, llvm::APSInt Hint) {
    Criticals.try_emplace(D->getDirectiveName().getAsString(), D, Hint);
  }
  const std::pair<const OMPCriticalDirective *, llvm::APSInt>
  getCriticalWithHint(const DeclarationNameInfo &Name) const {
    auto I = Criticals.find(Name.getAsString());
    if (I != Criticals.end())
      return I->second;
    return std::make_pair(nullptr, llvm::APSInt());
  }
  /// If 'aligned' declaration for given variable \a D was not seen yet,
  /// add it and return NULL; otherwise return previous occurrence's expression
  /// for diagnostics.
  const Expr *addUniqueAligned(const ValueDecl *D, const Expr *NewDE);
  /// If 'nontemporal' declaration for given variable \a D was not seen yet,
  /// add it and return NULL; otherwise return previous occurrence's expression
  /// for diagnostics.
  const Expr *addUniqueNontemporal(const ValueDecl *D, const Expr *NewDE);
 
  /// Register specified variable as loop control variable.
  void addLoopControlVariable(const ValueDecl *D, VarDecl *Capture);
  /// Check if the specified variable is a loop control variable for
  /// current region.
  /// \return The index of the loop control variable in the list of associated
  /// for-loops (from outer to inner).
  const LCDeclInfo isLoopControlVariable(const ValueDecl *D) const;
  /// Check if the specified variable is a loop control variable for
  /// parent region.
  /// \return The index of the loop control variable in the list of associated
  /// for-loops (from outer to inner).
  const LCDeclInfo isParentLoopControlVariable(const ValueDecl *D) const;
  /// Check if the specified variable is a loop control variable for
  /// current region.
  /// \return The index of the loop control variable in the list of associated
  /// for-loops (from outer to inner).
  const LCDeclInfo isLoopControlVariable(const ValueDecl *D,
                                         unsigned Level) const;
  /// Get the loop control variable for the I-th loop (or nullptr) in
  /// parent directive.
  const ValueDecl *getParentLoopControlVariable(unsigned I) const;
 
  /// Marks the specified decl \p D as used in scan directive.
  void markDeclAsUsedInScanDirective(ValueDecl *D) {
    if (SharingMapTy *Stack = getSecondOnStackOrNull())
      Stack->UsedInScanDirective.insert(D);
  }
 
  /// Checks if the specified declaration was used in the inner scan directive.
  bool isUsedInScanDirective(ValueDecl *D) const {
    if (const SharingMapTy *Stack = getTopOfStackOrNull())
      return Stack->UsedInScanDirective.contains(D);
    return false;
  }
 
  /// Adds explicit data sharing attribute to the specified declaration.
  void addDSA(const ValueDecl *D, const Expr *E, OpenMPClauseKind A,
              DeclRefExpr *PrivateCopy = nullptr, unsigned Modifier = 0,
              bool AppliedToPointee = false);
 
  /// Adds additional information for the reduction items with the reduction id
  /// represented as an operator.
  void addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                 BinaryOperatorKind BOK);
  /// Adds additional information for the reduction items with the reduction id
  /// represented as reduction identifier.
  void addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                 const Expr *ReductionRef);
  /// Returns the location and reduction operation from the innermost parent
  /// region for the given \p D.
  const DSAVarData
  getTopMostTaskgroupReductionData(const ValueDecl *D, SourceRange &SR,
                                   BinaryOperatorKind &BOK,
                                   Expr *&TaskgroupDescriptor) const;
  /// Returns the location and reduction operation from the innermost parent
  /// region for the given \p D.
  const DSAVarData
  getTopMostTaskgroupReductionData(const ValueDecl *D, SourceRange &SR,
                                   const Expr *&ReductionRef,
                                   Expr *&TaskgroupDescriptor) const;
  /// Return reduction reference expression for the current taskgroup or
  /// parallel/worksharing directives with task reductions.
  Expr *getTaskgroupReductionRef() const {
    assert((getTopOfStack().Directive == OMPD_taskgroup ||
            ((isOpenMPParallelDirective(getTopOfStack().Directive) ||
              isOpenMPWorksharingDirective(getTopOfStack().Directive)) &&
             !isOpenMPSimdDirective(getTopOfStack().Directive))) &&
           "taskgroup reference expression requested for non taskgroup or "
           "parallel/worksharing directive.");
    return getTopOfStack().TaskgroupReductionRef;
  }
  /// Checks if the given \p VD declaration is actually a taskgroup reduction
  /// descriptor variable at the \p Level of OpenMP regions.
  bool isTaskgroupReductionRef(const ValueDecl *VD, unsigned Level) const {
    return getStackElemAtLevel(Level).TaskgroupReductionRef &&
           cast<DeclRefExpr>(getStackElemAtLevel(Level).TaskgroupReductionRef)
                   ->getDecl() == VD;
  }
 
  /// Returns data sharing attributes from top of the stack for the
  /// specified declaration.
  const DSAVarData getTopDSA(ValueDecl *D, bool FromParent);
  /// Returns data-sharing attributes for the specified declaration.
  const DSAVarData getImplicitDSA(ValueDecl *D, bool FromParent) const;
  /// Returns data-sharing attributes for the specified declaration.
  const DSAVarData getImplicitDSA(ValueDecl *D, unsigned Level) const;
  /// Checks if the specified variables has data-sharing attributes which
  /// match specified \a CPred predicate in any directive which matches \a DPred
  /// predicate.
  const DSAVarData
  hasDSA(ValueDecl *D,
         const llvm::function_ref<bool(OpenMPClauseKind, bool,
                                       DefaultDataSharingAttributes)>
             CPred,
         const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
         bool FromParent) const;
  /// Checks if the specified variables has data-sharing attributes which
  /// match specified \a CPred predicate in any innermost directive which
  /// matches \a DPred predicate.
  const DSAVarData
  hasInnermostDSA(ValueDecl *D,
                  const llvm::function_ref<bool(OpenMPClauseKind, bool)> CPred,
                  const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
                  bool FromParent) const;
  /// Checks if the specified variables has explicit data-sharing
  /// attributes which match specified \a CPred predicate at the specified
  /// OpenMP region.
  bool
  hasExplicitDSA(const ValueDecl *D,
                 const llvm::function_ref<bool(OpenMPClauseKind, bool)> CPred,
                 unsigned Level, bool NotLastprivate = false) const;
 
  /// Returns true if the directive at level \Level matches in the
  /// specified \a DPred predicate.
  bool hasExplicitDirective(
      const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
      unsigned Level) const;
 
  /// Finds a directive which matches specified \a DPred predicate.
  bool hasDirective(
      const llvm::function_ref<bool(
          OpenMPDirectiveKind, const DeclarationNameInfo &, SourceLocation)>
          DPred,
      bool FromParent) const;
 
  /// Returns currently analyzed directive.
  OpenMPDirectiveKind getCurrentDirective() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->Directive : OMPD_unknown;
  }
  /// Returns directive kind at specified level.
  OpenMPDirectiveKind getDirective(unsigned Level) const {
    assert(!isStackEmpty() && "No directive at specified level.");
    return getStackElemAtLevel(Level).Directive;
  }
  /// Returns the capture region at the specified level.
  OpenMPDirectiveKind getCaptureRegion(unsigned Level,
                                       unsigned OpenMPCaptureLevel) const {
    SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
    getOpenMPCaptureRegions(CaptureRegions, getDirective(Level));
    return CaptureRegions[OpenMPCaptureLevel];
  }
  /// Returns parent directive.
  OpenMPDirectiveKind getParentDirective() const {
    const SharingMapTy *Parent = getSecondOnStackOrNull();
    return Parent ? Parent->Directive : OMPD_unknown;
  }
 
  /// Add requires decl to internal vector
  void addRequiresDecl(OMPRequiresDecl *RD) { RequiresDecls.push_back(RD); }
 
  /// Checks if the defined 'requires' directive has specified type of clause.
  template <typename ClauseType> bool hasRequiresDeclWithClause() const {
    return llvm::any_of(RequiresDecls, [](const OMPRequiresDecl *D) {
      return llvm::any_of(D->clauselists(), [](const OMPClause *C) {
        return isa<ClauseType>(C);
      });
    });
  }
 
  /// Checks for a duplicate clause amongst previously declared requires
  /// directives
  bool hasDuplicateRequiresClause(ArrayRef<OMPClause *> ClauseList) const {
    bool IsDuplicate = false;
    for (OMPClause *CNew : ClauseList) {
      for (const OMPRequiresDecl *D : RequiresDecls) {
        for (const OMPClause *CPrev : D->clauselists()) {
          if (CNew->getClauseKind() == CPrev->getClauseKind()) {
            SemaRef.Diag(CNew->getBeginLoc(),
                         diag::err_omp_requires_clause_redeclaration)
                << getOpenMPClauseName(CNew->getClauseKind());
            SemaRef.Diag(CPrev->getBeginLoc(),
                         diag::note_omp_requires_previous_clause)
                << getOpenMPClauseName(CPrev->getClauseKind());
            IsDuplicate = true;
          }
        }
      }
    }
    return IsDuplicate;
  }
 
  /// Add location of previously encountered target to internal vector
  void addTargetDirLocation(SourceLocation LocStart) {
    TargetLocations.push_back(LocStart);
  }
 
  /// Add location for the first encountered atomicc directive.
  void addAtomicDirectiveLoc(SourceLocation Loc) {
    if (AtomicLocation.isInvalid())
      AtomicLocation = Loc;
  }
 
  /// Returns the location of the first encountered atomic directive in the
  /// module.
  SourceLocation getAtomicDirectiveLoc() const { return AtomicLocation; }
 
  // Return previously encountered target region locations.
  ArrayRef<SourceLocation> getEncounteredTargetLocs() const {
    return TargetLocations;
  }
 
  /// Set default data sharing attribute to none.
  void setDefaultDSANone(SourceLocation Loc) {
    getTopOfStack().DefaultAttr = DSA_none;
    getTopOfStack().DefaultAttrLoc = Loc;
  }
  /// Set default data sharing attribute to shared.
  void setDefaultDSAShared(SourceLocation Loc) {
    getTopOfStack().DefaultAttr = DSA_shared;
    getTopOfStack().DefaultAttrLoc = Loc;
  }
  /// Set default data sharing attribute to private.
  void setDefaultDSAPrivate(SourceLocation Loc) {
    getTopOfStack().DefaultAttr = DSA_private;
    getTopOfStack().DefaultAttrLoc = Loc;
  }
  /// Set default data sharing attribute to firstprivate.
  void setDefaultDSAFirstPrivate(SourceLocation Loc) {
    getTopOfStack().DefaultAttr = DSA_firstprivate;
    getTopOfStack().DefaultAttrLoc = Loc;
  }
  /// Set default data mapping attribute to Modifier:Kind
  void setDefaultDMAAttr(OpenMPDefaultmapClauseModifier M,
                         OpenMPDefaultmapClauseKind Kind, SourceLocation Loc) {
    DefaultmapInfo &DMI = getTopOfStack().DefaultmapMap[Kind];
    DMI.ImplicitBehavior = M;
    DMI.SLoc = Loc;
  }
  /// Check whether the implicit-behavior has been set in defaultmap
  bool checkDefaultmapCategory(OpenMPDefaultmapClauseKind VariableCategory) {
    if (VariableCategory == OMPC_DEFAULTMAP_unknown)
      return getTopOfStack()
                     .DefaultmapMap[OMPC_DEFAULTMAP_aggregate]
                     .ImplicitBehavior != OMPC_DEFAULTMAP_MODIFIER_unknown ||
             getTopOfStack()
                     .DefaultmapMap[OMPC_DEFAULTMAP_scalar]
                     .ImplicitBehavior != OMPC_DEFAULTMAP_MODIFIER_unknown ||
             getTopOfStack()
                     .DefaultmapMap[OMPC_DEFAULTMAP_pointer]
                     .ImplicitBehavior != OMPC_DEFAULTMAP_MODIFIER_unknown;
    return getTopOfStack().DefaultmapMap[VariableCategory].ImplicitBehavior !=
           OMPC_DEFAULTMAP_MODIFIER_unknown;
  }
 
  ArrayRef<llvm::omp::TraitProperty> getConstructTraits() {
    return ConstructTraits;
  }
  void handleConstructTrait(ArrayRef<llvm::omp::TraitProperty> Traits,
                            bool ScopeEntry) {
    if (ScopeEntry)
      ConstructTraits.append(Traits.begin(), Traits.end());
    else
      for (llvm::omp::TraitProperty Trait : llvm::reverse(Traits)) {
        llvm::omp::TraitProperty Top = ConstructTraits.pop_back_val();
        assert(Top == Trait && "Something left a trait on the stack!");
        (void)Trait;
        (void)Top;
      }
  }
 
  DefaultDataSharingAttributes getDefaultDSA(unsigned Level) const {
    return getStackSize() <= Level ? DSA_unspecified
                                   : getStackElemAtLevel(Level).DefaultAttr;
  }
  DefaultDataSharingAttributes getDefaultDSA() const {
    return isStackEmpty() ? DSA_unspecified : getTopOfStack().DefaultAttr;
  }
  SourceLocation getDefaultDSALocation() const {
    return isStackEmpty() ? SourceLocation() : getTopOfStack().DefaultAttrLoc;
  }
  OpenMPDefaultmapClauseModifier
  getDefaultmapModifier(OpenMPDefaultmapClauseKind Kind) const {
    return isStackEmpty()
               ? OMPC_DEFAULTMAP_MODIFIER_unknown
               : getTopOfStack().DefaultmapMap[Kind].ImplicitBehavior;
  }
  OpenMPDefaultmapClauseModifier
  getDefaultmapModifierAtLevel(unsigned Level,
                               OpenMPDefaultmapClauseKind Kind) const {
    return getStackElemAtLevel(Level).DefaultmapMap[Kind].ImplicitBehavior;
  }
  bool isDefaultmapCapturedByRef(unsigned Level,
                                 OpenMPDefaultmapClauseKind Kind) const {
    OpenMPDefaultmapClauseModifier M =
        getDefaultmapModifierAtLevel(Level, Kind);
    if (Kind == OMPC_DEFAULTMAP_scalar || Kind == OMPC_DEFAULTMAP_pointer) {
      return (M == OMPC_DEFAULTMAP_MODIFIER_alloc) ||
             (M == OMPC_DEFAULTMAP_MODIFIER_to) ||
             (M == OMPC_DEFAULTMAP_MODIFIER_from) ||
             (M == OMPC_DEFAULTMAP_MODIFIER_tofrom);
    }
    return true;
  }
  static bool mustBeFirstprivateBase(OpenMPDefaultmapClauseModifier M,
                                     OpenMPDefaultmapClauseKind Kind) {
    switch (Kind) {
    case OMPC_DEFAULTMAP_scalar:
    case OMPC_DEFAULTMAP_pointer:
      return (M == OMPC_DEFAULTMAP_MODIFIER_unknown) ||
             (M == OMPC_DEFAULTMAP_MODIFIER_firstprivate) ||
             (M == OMPC_DEFAULTMAP_MODIFIER_default);
    case OMPC_DEFAULTMAP_aggregate:
      return M == OMPC_DEFAULTMAP_MODIFIER_firstprivate;
    default:
      break;
    }
    llvm_unreachable("Unexpected OpenMPDefaultmapClauseKind enum");
  }
  bool mustBeFirstprivateAtLevel(unsigned Level,
                                 OpenMPDefaultmapClauseKind Kind) const {
    OpenMPDefaultmapClauseModifier M =
        getDefaultmapModifierAtLevel(Level, Kind);
    return mustBeFirstprivateBase(M, Kind);
  }
  bool mustBeFirstprivate(OpenMPDefaultmapClauseKind Kind) const {
    OpenMPDefaultmapClauseModifier M = getDefaultmapModifier(Kind);
    return mustBeFirstprivateBase(M, Kind);
  }
 
  /// Checks if the specified variable is a threadprivate.
  bool isThreadPrivate(VarDecl *D) {
    const DSAVarData DVar = getTopDSA(D, false);
    return isOpenMPThreadPrivate(DVar.CKind);
  }
 
  /// Marks current region as ordered (it has an 'ordered' clause).
  void setOrderedRegion(bool IsOrdered, const Expr *Param,
                        OMPOrderedClause *Clause) {
    if (IsOrdered)
      getTopOfStack().OrderedRegion.emplace(Param, Clause);
    else
      getTopOfStack().OrderedRegion.reset();
  }
  /// Returns true, if region is ordered (has associated 'ordered' clause),
  /// false - otherwise.
  bool isOrderedRegion() const {
    if (const SharingMapTy *Top = getTopOfStackOrNull())
      return Top->OrderedRegion.has_value();
    return false;
  }
  /// Returns optional parameter for the ordered region.
  std::pair<const Expr *, OMPOrderedClause *> getOrderedRegionParam() const {
    if (const SharingMapTy *Top = getTopOfStackOrNull())
      if (Top->OrderedRegion)
        return Top->OrderedRegion.value();
    return std::make_pair(nullptr, nullptr);
  }
  /// Returns true, if parent region is ordered (has associated
  /// 'ordered' clause), false - otherwise.
  bool isParentOrderedRegion() const {
    if (const SharingMapTy *Parent = getSecondOnStackOrNull())
      return Parent->OrderedRegion.has_value();
    return false;
  }
  /// Returns optional parameter for the ordered region.
  std::pair<const Expr *, OMPOrderedClause *>
  getParentOrderedRegionParam() const {
    if (const SharingMapTy *Parent = getSecondOnStackOrNull())
      if (Parent->OrderedRegion)
        return Parent->OrderedRegion.value();
    return std::make_pair(nullptr, nullptr);
  }
  /// Marks current region as nowait (it has a 'nowait' clause).
  void setNowaitRegion(bool IsNowait = true) {
    getTopOfStack().NowaitRegion = IsNowait;
  }
  /// Returns true, if parent region is nowait (has associated
  /// 'nowait' clause), false - otherwise.
  bool isParentNowaitRegion() const {
    if (const SharingMapTy *Parent = getSecondOnStackOrNull())
      return Parent->NowaitRegion;
    return false;
  }
  /// Marks current region as untied (it has a 'untied' clause).
  void setUntiedRegion(bool IsUntied = true) {
    getTopOfStack().UntiedRegion = IsUntied;
  }
  /// Return true if current region is untied.
  bool isUntiedRegion() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->UntiedRegion : false;
  }
  /// Marks parent region as cancel region.
  void setParentCancelRegion(bool Cancel = true) {
    if (SharingMapTy *Parent = getSecondOnStackOrNull())
      Parent->CancelRegion |= Cancel;
  }
  /// Return true if current region has inner cancel construct.
  bool isCancelRegion() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->CancelRegion : false;
  }
 
  /// Mark that parent region already has scan directive.
  void setParentHasScanDirective(SourceLocation Loc) {
    if (SharingMapTy *Parent = getSecondOnStackOrNull())
      Parent->PrevScanLocation = Loc;
  }
  /// Return true if current region has inner cancel construct.
  bool doesParentHasScanDirective() const {
    const SharingMapTy *Top = getSecondOnStackOrNull();
    return Top ? Top->PrevScanLocation.isValid() : false;
  }
  /// Return true if current region has inner cancel construct.
  SourceLocation getParentScanDirectiveLoc() const {
    const SharingMapTy *Top = getSecondOnStackOrNull();
    return Top ? Top->PrevScanLocation : SourceLocation();
  }
  /// Mark that parent region already has ordered directive.
  void setParentHasOrderedDirective(SourceLocation Loc) {
    if (SharingMapTy *Parent = getSecondOnStackOrNull())
      Parent->PrevOrderedLocation = Loc;
  }
  /// Return true if current region has inner ordered construct.
  bool doesParentHasOrderedDirective() const {
    const SharingMapTy *Top = getSecondOnStackOrNull();
    return Top ? Top->PrevOrderedLocation.isValid() : false;
  }
  /// Returns the location of the previously specified ordered directive.
  SourceLocation getParentOrderedDirectiveLoc() const {
    const SharingMapTy *Top = getSecondOnStackOrNull();
    return Top ? Top->PrevOrderedLocation : SourceLocation();
  }
 
  /// Set collapse value for the region.
  void setAssociatedLoops(unsigned Val) {
    getTopOfStack().AssociatedLoops = Val;
    if (Val > 1)
      getTopOfStack().HasMutipleLoops = true;
  }
  /// Return collapse value for region.
  unsigned getAssociatedLoops() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->AssociatedLoops : 0;
  }
  /// Returns true if the construct is associated with multiple loops.
  bool hasMutipleLoops() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->HasMutipleLoops : false;
  }
 
  /// Marks current target region as one with closely nested teams
  /// region.
  void setParentTeamsRegionLoc(SourceLocation TeamsRegionLoc) {
    if (SharingMapTy *Parent = getSecondOnStackOrNull())
      Parent->InnerTeamsRegionLoc = TeamsRegionLoc;
  }
  /// Returns true, if current region has closely nested teams region.
  bool hasInnerTeamsRegion() const {
    return getInnerTeamsRegionLoc().isValid();
  }
  /// Returns location of the nested teams region (if any).
  SourceLocation getInnerTeamsRegionLoc() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->InnerTeamsRegionLoc : SourceLocation();
  }
 
  Scope *getCurScope() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->CurScope : nullptr;
  }
  void setContext(DeclContext *DC) { getTopOfStack().Context = DC; }
  SourceLocation getConstructLoc() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->ConstructLoc : SourceLocation();
  }
 
  /// Do the check specified in \a Check to all component lists and return true
  /// if any issue is found.
  bool checkMappableExprComponentListsForDecl(
      const ValueDecl *VD, bool CurrentRegionOnly,
      const llvm::function_ref<
          bool(OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind)>
          Check) const {
    if (isStackEmpty())
      return false;
    auto SI = begin();
    auto SE = end();
 
    if (SI == SE)
      return false;
 
    if (CurrentRegionOnly)
      SE = std::next(SI);
    else
      std::advance(SI, 1);
 
    for (; SI != SE; ++SI) {
      auto MI = SI->MappedExprComponents.find(VD);
      if (MI != SI->MappedExprComponents.end())
        for (OMPClauseMappableExprCommon::MappableExprComponentListRef L :
             MI->second.Components)
          if (Check(L, MI->second.Kind))
            return true;
    }
    return false;
  }
 
  /// Do the check specified in \a Check to all component lists at a given level
  /// and return true if any issue is found.
  bool checkMappableExprComponentListsForDeclAtLevel(
      const ValueDecl *VD, unsigned Level,
      const llvm::function_ref<
          bool(OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind)>
          Check) const {
    if (getStackSize() <= Level)
      return false;
 
    const SharingMapTy &StackElem = getStackElemAtLevel(Level);
    auto MI = StackElem.MappedExprComponents.find(VD);
    if (MI != StackElem.MappedExprComponents.end())
      for (OMPClauseMappableExprCommon::MappableExprComponentListRef L :
           MI->second.Components)
        if (Check(L, MI->second.Kind))
          return true;
    return false;
  }
 
  /// Create a new mappable expression component list associated with a given
  /// declaration and initialize it with the provided list of components.
  void addMappableExpressionComponents(
      const ValueDecl *VD,
      OMPClauseMappableExprCommon::MappableExprComponentListRef Components,
      OpenMPClauseKind WhereFoundClauseKind) {
    MappedExprComponentTy &MEC = getTopOfStack().MappedExprComponents[VD];
    // Create new entry and append the new components there.
    MEC.Components.resize(MEC.Components.size() + 1);
    MEC.Components.back().append(Components.begin(), Components.end());
    MEC.Kind = WhereFoundClauseKind;
  }
 
  unsigned getNestingLevel() const {
    assert(!isStackEmpty());
    return getStackSize() - 1;
  }
  void addDoacrossDependClause(OMPDependClause *C,
                               const OperatorOffsetTy &OpsOffs) {
    SharingMapTy *Parent = getSecondOnStackOrNull();
    assert(Parent && isOpenMPWorksharingDirective(Parent->Directive));
    Parent->DoacrossDepends.try_emplace(C, OpsOffs);
  }
  llvm::iterator_range<DoacrossDependMapTy::const_iterator>
  getDoacrossDependClauses() const {
    const SharingMapTy &StackElem = getTopOfStack();
    if (isOpenMPWorksharingDirective(StackElem.Directive)) {
      const DoacrossDependMapTy &Ref = StackElem.DoacrossDepends;
      return llvm::make_range(Ref.begin(), Ref.end());
    }
    return llvm::make_range(StackElem.DoacrossDepends.end(),
                            StackElem.DoacrossDepends.end());
  }
 
  // Store types of classes which have been explicitly mapped
  void addMappedClassesQualTypes(QualType QT) {
    SharingMapTy &StackElem = getTopOfStack();
    StackElem.MappedClassesQualTypes.insert(QT);
  }
 
  // Return set of mapped classes types
  bool isClassPreviouslyMapped(QualType QT) const {
    const SharingMapTy &StackElem = getTopOfStack();
    return StackElem.MappedClassesQualTypes.contains(QT);
  }
 
  /// Adds global declare target to the parent target region.
  void addToParentTargetRegionLinkGlobals(DeclRefExpr *E) {
    assert(*OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(
               E->getDecl()) == OMPDeclareTargetDeclAttr::MT_Link &&
           "Expected declare target link global.");
    for (auto &Elem : *this) {
      if (isOpenMPTargetExecutionDirective(Elem.Directive)) {
        Elem.DeclareTargetLinkVarDecls.push_back(E);
        return;
      }
    }
  }
 
  /// Returns the list of globals with declare target link if current directive
  /// is target.
  ArrayRef<DeclRefExpr *> getLinkGlobals() const {
    assert(isOpenMPTargetExecutionDirective(getCurrentDirective()) &&
           "Expected target executable directive.");
    return getTopOfStack().DeclareTargetLinkVarDecls;
  }
 
  /// Adds list of allocators expressions.
  void addInnerAllocatorExpr(Expr *E) {
    getTopOfStack().InnerUsedAllocators.push_back(E);
  }
  /// Return list of used allocators.
  ArrayRef<Expr *> getInnerAllocators() const {
    return getTopOfStack().InnerUsedAllocators;
  }
  /// Marks the declaration as implicitly firstprivate nin the task-based
  /// regions.
  void addImplicitTaskFirstprivate(unsigned Level, Decl *D) {
    getStackElemAtLevel(Level).ImplicitTaskFirstprivates.insert(D);
  }
  /// Checks if the decl is implicitly firstprivate in the task-based region.
  bool isImplicitTaskFirstprivate(Decl *D) const {
    return getTopOfStack().ImplicitTaskFirstprivates.contains(D);
  }
 
  /// Marks decl as used in uses_allocators clause as the allocator.
  void addUsesAllocatorsDecl(const Decl *D, UsesAllocatorsDeclKind Kind) {
    getTopOfStack().UsesAllocatorsDecls.try_emplace(D, Kind);
  }
  /// Checks if specified decl is used in uses allocator clause as the
  /// allocator.
  Optional<UsesAllocatorsDeclKind> isUsesAllocatorsDecl(unsigned Level,
                                                        const Decl *D) const {
    const SharingMapTy &StackElem = getTopOfStack();
    auto I = StackElem.UsesAllocatorsDecls.find(D);
    if (I == StackElem.UsesAllocatorsDecls.end())
      return None;
    return I->getSecond();
  }
  Optional<UsesAllocatorsDeclKind> isUsesAllocatorsDecl(const Decl *D) const {
    const SharingMapTy &StackElem = getTopOfStack();
    auto I = StackElem.UsesAllocatorsDecls.find(D);
    if (I == StackElem.UsesAllocatorsDecls.end())
      return None;
    return I->getSecond();
  }
 
  void addDeclareMapperVarRef(Expr *Ref) {
    SharingMapTy &StackElem = getTopOfStack();
    StackElem.DeclareMapperVar = Ref;
  }
  const Expr *getDeclareMapperVarRef() const {
    const SharingMapTy *Top = getTopOfStackOrNull();
    return Top ? Top->DeclareMapperVar : nullptr;
  }
  /// get captured field from ImplicitDefaultFirstprivateFDs
  VarDecl *getImplicitFDCapExprDecl(const FieldDecl *FD) const {
    const_iterator I = begin();
    const_iterator EndI = end();
    size_t StackLevel = getStackSize();
    for (; I != EndI; ++I) {
      if (I->DefaultAttr == DSA_firstprivate || I->DefaultAttr == DSA_private)
        break;
      StackLevel--;
    }
    assert((StackLevel > 0 && I != EndI) || (StackLevel == 0 && I == EndI));
    if (I == EndI)
      return nullptr;
    for (const auto &IFD : I->ImplicitDefaultFirstprivateFDs)
      if (IFD.FD == FD && IFD.StackLevel == StackLevel)
        return IFD.VD;
    return nullptr;
  }
  /// Check if capture decl is field captured in ImplicitDefaultFirstprivateFDs
  bool isImplicitDefaultFirstprivateFD(VarDecl *VD) const {
    const_iterator I = begin();
    const_iterator EndI = end();
    for (; I != EndI; ++I)
      if (I->DefaultAttr == DSA_firstprivate || I->DefaultAttr == DSA_private)
        break;
    if (I == EndI)
      return false;
    for (const auto &IFD : I->ImplicitDefaultFirstprivateFDs)
      if (IFD.VD == VD)
        return true;
    return false;
  }
  /// Store capture FD info in ImplicitDefaultFirstprivateFDs
  void addImplicitDefaultFirstprivateFD(const FieldDecl *FD, VarDecl *VD) {
    iterator I = begin();
    const_iterator EndI = end();
    size_t StackLevel = getStackSize();
    for (; I != EndI; ++I) {
      if (I->DefaultAttr == DSA_private || I->DefaultAttr == DSA_firstprivate) {
        I->ImplicitDefaultFirstprivateFDs.emplace_back(FD, StackLevel, VD);
        break;
      }
      StackLevel--;
    }
    assert((StackLevel > 0 && I != EndI) || (StackLevel == 0 && I == EndI));
  }
};
 
bool isImplicitTaskingRegion(OpenMPDirectiveKind DKind) {
  return isOpenMPParallelDirective(DKind) || isOpenMPTeamsDirective(DKind);
}
 
bool isImplicitOrExplicitTaskingRegion(OpenMPDirectiveKind DKind) {
  return isImplicitTaskingRegion(DKind) || isOpenMPTaskingDirective(DKind) ||
         DKind == OMPD_unknown;
}
 
} // namespace
 
static const Expr *getExprAsWritten(const Expr *E) {
  if (const auto *FE = dyn_cast<FullExpr>(E))
    E = FE->getSubExpr();
 
  if (const auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
    E = MTE->getSubExpr();
 
  while (const auto *Binder = dyn_cast<CXXBindTemporaryExpr>(E))
    E = Binder->getSubExpr();
 
  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(E))
    E = ICE->getSubExprAsWritten();
  return E->IgnoreParens();
}
 
static Expr *getExprAsWritten(Expr *E) {
  return const_cast<Expr *>(getExprAsWritten(const_cast<const Expr *>(E)));
}
 
static const ValueDecl *getCanonicalDecl(const ValueDecl *D) {
  if (const auto *CED = dyn_cast<OMPCapturedExprDecl>(D))
    if (const auto *ME = dyn_cast<MemberExpr>(getExprAsWritten(CED->getInit())))
      D = ME->getMemberDecl();
  const auto *VD = dyn_cast<VarDecl>(D);
  const auto *FD = dyn_cast<FieldDecl>(D);
  if (VD != nullptr) {
    VD = VD->getCanonicalDecl();
    D = VD;
  } else {
    assert(FD);
    FD = FD->getCanonicalDecl();
    D = FD;
  }
  return D;
}
 
static ValueDecl *getCanonicalDecl(ValueDecl *D) {
  return const_cast<ValueDecl *>(
      getCanonicalDecl(const_cast<const ValueDecl *>(D)));
}
 
DSAStackTy::DSAVarData DSAStackTy::getDSA(const_iterator &Iter,
                                          ValueDecl *D) const {
  D = getCanonicalDecl(D);
  auto *VD = dyn_cast<VarDecl>(D);
  const auto *FD = dyn_cast<FieldDecl>(D);
  DSAVarData DVar;
  if (Iter == end()) {
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a region but not in construct]
    //  File-scope or namespace-scope variables referenced in called routines
    //  in the region are shared unless they appear in a threadprivate
    //  directive.
    if (VD && !VD->isFunctionOrMethodVarDecl() && !isa<ParmVarDecl>(VD))
      DVar.CKind = OMPC_shared;
 
    // OpenMP [2.9.1.2, Data-sharing Attribute Rules for Variables Referenced
    // in a region but not in construct]
    //  Variables with static storage duration that are declared in called
    //  routines in the region are shared.
    if (VD && VD->hasGlobalStorage())
      DVar.CKind = OMPC_shared;
 
    // Non-static data members are shared by default.
    if (FD)
      DVar.CKind = OMPC_shared;
 
    return DVar;
  }
 
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  // Variables with automatic storage duration that are declared in a scope
  // inside the construct are private.
  if (VD && isOpenMPLocal(VD, Iter) && VD->isLocalVarDecl() &&
      (VD->getStorageClass() == SC_Auto || VD->getStorageClass() == SC_None)) {
    DVar.CKind = OMPC_private;
    return DVar;
  }
 
  DVar.DKind = Iter->Directive;
  // Explicitly specified attributes and local variables with predetermined
  // attributes.
  if (Iter->SharingMap.count(D)) {
    const DSAInfo &Data = Iter->SharingMap.lookup(D);
    DVar.RefExpr = Data.RefExpr.getPointer();
    DVar.PrivateCopy = Data.PrivateCopy;
    DVar.CKind = Data.Attributes;
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    DVar.Modifier = Data.Modifier;
    DVar.AppliedToPointee = Data.AppliedToPointee;
    return DVar;
  }
 
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, implicitly determined, p.1]
  //  In a parallel or task construct, the data-sharing attributes of these
  //  variables are determined by the default clause, if present.
  switch (Iter->DefaultAttr) {
  case DSA_shared:
    DVar.CKind = OMPC_shared;
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    return DVar;
  case DSA_none:
    return DVar;
  case DSA_firstprivate:
    if (VD && VD->getStorageDuration() == SD_Static &&
        VD->getDeclContext()->isFileContext()) {
      DVar.CKind = OMPC_unknown;
    } else {
      DVar.CKind = OMPC_firstprivate;
    }
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    return DVar;
  case DSA_private:
    // each variable with static storage duration that is declared
    // in a namespace or global scope and referenced in the construct,
    // and that does not have a predetermined data-sharing attribute
    if (VD && VD->getStorageDuration() == SD_Static &&
        VD->getDeclContext()->isFileContext()) {
      DVar.CKind = OMPC_unknown;
    } else {
      DVar.CKind = OMPC_private;
    }
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    return DVar;
  case DSA_unspecified:
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, implicitly determined, p.2]
    //  In a parallel construct, if no default clause is present, these
    //  variables are shared.
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    if ((isOpenMPParallelDirective(DVar.DKind) &&
         !isOpenMPTaskLoopDirective(DVar.DKind)) ||
        isOpenMPTeamsDirective(DVar.DKind)) {
      DVar.CKind = OMPC_shared;
      return DVar;
    }
 
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, implicitly determined, p.4]
    //  In a task construct, if no default clause is present, a variable that in
    //  the enclosing context is determined to be shared by all implicit tasks
    //  bound to the current team is shared.
    if (isOpenMPTaskingDirective(DVar.DKind)) {
      DSAVarData DVarTemp;
      const_iterator I = Iter, E = end();
      do {
        ++I;
        // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables
        // Referenced in a Construct, implicitly determined, p.6]
        //  In a task construct, if no default clause is present, a variable
        //  whose data-sharing attribute is not determined by the rules above is
        //  firstprivate.
        DVarTemp = getDSA(I, D);
        if (DVarTemp.CKind != OMPC_shared) {
          DVar.RefExpr = nullptr;
          DVar.CKind = OMPC_firstprivate;
          return DVar;
        }
      } while (I != E && !isImplicitTaskingRegion(I->Directive));
      DVar.CKind =
          (DVarTemp.CKind == OMPC_unknown) ? OMPC_firstprivate : OMPC_shared;
      return DVar;
    }
  }
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, implicitly determined, p.3]
  //  For constructs other than task, if no default clause is present, these
  //  variables inherit their data-sharing attributes from the enclosing
  //  context.
  return getDSA(++Iter, D);
}
 
const Expr *DSAStackTy::addUniqueAligned(const ValueDecl *D,
                                         const Expr *NewDE) {
  assert(!isStackEmpty() && "Data sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  SharingMapTy &StackElem = getTopOfStack();
  auto It = StackElem.AlignedMap.find(D);
  if (It == StackElem.AlignedMap.end()) {
    assert(NewDE && "Unexpected nullptr expr to be added into aligned map");
    StackElem.AlignedMap[D] = NewDE;
    return nullptr;
  }
  assert(It->second && "Unexpected nullptr expr in the aligned map");
  return It->second;
}
 
const Expr *DSAStackTy::addUniqueNontemporal(const ValueDecl *D,
                                             const Expr *NewDE) {
  assert(!isStackEmpty() && "Data sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  SharingMapTy &StackElem = getTopOfStack();
  auto It = StackElem.NontemporalMap.find(D);
  if (It == StackElem.NontemporalMap.end()) {
    assert(NewDE && "Unexpected nullptr expr to be added into aligned map");
    StackElem.NontemporalMap[D] = NewDE;
    return nullptr;
  }
  assert(It->second && "Unexpected nullptr expr in the aligned map");
  return It->second;
}
 
void DSAStackTy::addLoopControlVariable(const ValueDecl *D, VarDecl *Capture) {
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  SharingMapTy &StackElem = getTopOfStack();
  StackElem.LCVMap.try_emplace(
      D, LCDeclInfo(StackElem.LCVMap.size() + 1, Capture));
}
 
const DSAStackTy::LCDeclInfo
DSAStackTy::isLoopControlVariable(const ValueDecl *D) const {
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  const SharingMapTy &StackElem = getTopOfStack();
  auto It = StackElem.LCVMap.find(D);
  if (It != StackElem.LCVMap.end())
    return It->second;
  return {0, nullptr};
}
 
const DSAStackTy::LCDeclInfo
DSAStackTy::isLoopControlVariable(const ValueDecl *D, unsigned Level) const {
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  for (unsigned I = Level + 1; I > 0; --I) {
    const SharingMapTy &StackElem = getStackElemAtLevel(I - 1);
    auto It = StackElem.LCVMap.find(D);
    if (It != StackElem.LCVMap.end())
      return It->second;
  }
  return {0, nullptr};
}
 
const DSAStackTy::LCDeclInfo
DSAStackTy::isParentLoopControlVariable(const ValueDecl *D) const {
  const SharingMapTy *Parent = getSecondOnStackOrNull();
  assert(Parent && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  auto It = Parent->LCVMap.find(D);
  if (It != Parent->LCVMap.end())
    return It->second;
  return {0, nullptr};
}
 
const ValueDecl *DSAStackTy::getParentLoopControlVariable(unsigned I) const {
  const SharingMapTy *Parent = getSecondOnStackOrNull();
  assert(Parent && "Data-sharing attributes stack is empty");
  if (Parent->LCVMap.size() < I)
    return nullptr;
  for (const auto &Pair : Parent->LCVMap)
    if (Pair.second.first == I)
      return Pair.first;
  return nullptr;
}
 
void DSAStackTy::addDSA(const ValueDecl *D, const Expr *E, OpenMPClauseKind A,
                        DeclRefExpr *PrivateCopy, unsigned Modifier,
                        bool AppliedToPointee) {
  D = getCanonicalDecl(D);
  if (A == OMPC_threadprivate) {
    DSAInfo &Data = Threadprivates[D];
    Data.Attributes = A;
    Data.RefExpr.setPointer(E);
    Data.PrivateCopy = nullptr;
    Data.Modifier = Modifier;
  } else {
    DSAInfo &Data = getTopOfStack().SharingMap[D];
    assert(Data.Attributes == OMPC_unknown || (A == Data.Attributes) ||
           (A == OMPC_firstprivate && Data.Attributes == OMPC_lastprivate) ||
           (A == OMPC_lastprivate && Data.Attributes == OMPC_firstprivate) ||
           (isLoopControlVariable(D).first && A == OMPC_private));
    Data.Modifier = Modifier;
    if (A == OMPC_lastprivate && Data.Attributes == OMPC_firstprivate) {
      Data.RefExpr.setInt(/*IntVal=*/true);
      return;
    }
    const bool IsLastprivate =
        A == OMPC_lastprivate || Data.Attributes == OMPC_lastprivate;
    Data.Attributes = A;
    Data.RefExpr.setPointerAndInt(E, IsLastprivate);
    Data.PrivateCopy = PrivateCopy;
    Data.AppliedToPointee = AppliedToPointee;
    if (PrivateCopy) {
      DSAInfo &Data = getTopOfStack().SharingMap[PrivateCopy->getDecl()];
      Data.Modifier = Modifier;
      Data.Attributes = A;
      Data.RefExpr.setPointerAndInt(PrivateCopy, IsLastprivate);
      Data.PrivateCopy = nullptr;
      Data.AppliedToPointee = AppliedToPointee;
    }
  }
}
 
/// Build a variable declaration for OpenMP loop iteration variable.
static VarDecl *buildVarDecl(Sema &SemaRef, SourceLocation Loc, QualType Type,
                             StringRef Name, const AttrVec *Attrs = nullptr,
                             DeclRefExpr *OrigRef = nullptr) {
  DeclContext *DC = SemaRef.CurContext;
  IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
  TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
  auto *Decl =
      VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, TInfo, SC_None);
  if (Attrs) {
    for (specific_attr_iterator<AlignedAttr> I(Attrs->begin()), E(Attrs->end());
         I != E; ++I)
      Decl->addAttr(*I);
  }
  Decl->setImplicit();
  if (OrigRef) {
    Decl->addAttr(
        OMPReferencedVarAttr::CreateImplicit(SemaRef.Context, OrigRef));
  }
  return Decl;
}
 
static DeclRefExpr *buildDeclRefExpr(Sema &S, VarDecl *D, QualType Ty,
                                     SourceLocation Loc,
                                     bool RefersToCapture = false) {
  D->setReferenced();
  D->markUsed(S.Context);
  return DeclRefExpr::Create(S.getASTContext(), NestedNameSpecifierLoc(),
                             SourceLocation(), D, RefersToCapture, Loc, Ty,
                             VK_LValue);
}
 
void DSAStackTy::addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                           BinaryOperatorKind BOK) {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  assert(
      getTopOfStack().SharingMap[D].Attributes == OMPC_reduction &&
      "Additional reduction info may be specified only for reduction items.");
  ReductionData &ReductionData = getTopOfStack().ReductionMap[D];
  assert(ReductionData.ReductionRange.isInvalid() &&
         (getTopOfStack().Directive == OMPD_taskgroup ||
          ((isOpenMPParallelDirective(getTopOfStack().Directive) ||
            isOpenMPWorksharingDirective(getTopOfStack().Directive)) &&
           !isOpenMPSimdDirective(getTopOfStack().Directive))) &&
         "Additional reduction info may be specified only once for reduction "
         "items.");
  ReductionData.set(BOK, SR);
  Expr *&TaskgroupReductionRef = getTopOfStack().TaskgroupReductionRef;
  if (!TaskgroupReductionRef) {
    VarDecl *VD = buildVarDecl(SemaRef, SR.getBegin(),
                               SemaRef.Context.VoidPtrTy, ".task_red.");
    TaskgroupReductionRef =
        buildDeclRefExpr(SemaRef, VD, SemaRef.Context.VoidPtrTy, SR.getBegin());
  }
}
 
void DSAStackTy::addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                           const Expr *ReductionRef) {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  assert(
      getTopOfStack().SharingMap[D].Attributes == OMPC_reduction &&
      "Additional reduction info may be specified only for reduction items.");
  ReductionData &ReductionData = getTopOfStack().ReductionMap[D];
  assert(ReductionData.ReductionRange.isInvalid() &&
         (getTopOfStack().Directive == OMPD_taskgroup ||
          ((isOpenMPParallelDirective(getTopOfStack().Directive) ||
            isOpenMPWorksharingDirective(getTopOfStack().Directive)) &&
           !isOpenMPSimdDirective(getTopOfStack().Directive))) &&
         "Additional reduction info may be specified only once for reduction "
         "items.");
  ReductionData.set(ReductionRef, SR);
  Expr *&TaskgroupReductionRef = getTopOfStack().TaskgroupReductionRef;
  if (!TaskgroupReductionRef) {
    VarDecl *VD = buildVarDecl(SemaRef, SR.getBegin(),
                               SemaRef.Context.VoidPtrTy, ".task_red.");
    TaskgroupReductionRef =
        buildDeclRefExpr(SemaRef, VD, SemaRef.Context.VoidPtrTy, SR.getBegin());
  }
}
 
const DSAStackTy::DSAVarData DSAStackTy::getTopMostTaskgroupReductionData(
    const ValueDecl *D, SourceRange &SR, BinaryOperatorKind &BOK,
    Expr *&TaskgroupDescriptor) const {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty.");
  for (const_iterator I = begin() + 1, E = end(); I != E; ++I) {
    const DSAInfo &Data = I->SharingMap.lookup(D);
    if (Data.Attributes != OMPC_reduction ||
        Data.Modifier != OMPC_REDUCTION_task)
      continue;
    const ReductionData &ReductionData = I->ReductionMap.lookup(D);
    if (!ReductionData.ReductionOp ||
        ReductionData.ReductionOp.is<const Expr *>())
      return DSAVarData();
    SR = ReductionData.ReductionRange;
    BOK = ReductionData.ReductionOp.get<ReductionData::BOKPtrType>();
    assert(I->TaskgroupReductionRef && "taskgroup reduction reference "
                                       "expression for the descriptor is not "
                                       "set.");
    TaskgroupDescriptor = I->TaskgroupReductionRef;
    return DSAVarData(I->Directive, OMPC_reduction, Data.RefExpr.getPointer(),
                      Data.PrivateCopy, I->DefaultAttrLoc, OMPC_REDUCTION_task,
                      /*AppliedToPointee=*/false);
  }
  return DSAVarData();
}
 
const DSAStackTy::DSAVarData DSAStackTy::getTopMostTaskgroupReductionData(
    const ValueDecl *D, SourceRange &SR, const Expr *&ReductionRef,
    Expr *&TaskgroupDescriptor) const {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty.");
  for (const_iterator I = begin() + 1, E = end(); I != E; ++I) {
    const DSAInfo &Data = I->SharingMap.lookup(D);
    if (Data.Attributes != OMPC_reduction ||
        Data.Modifier != OMPC_REDUCTION_task)
      continue;
    const ReductionData &ReductionData = I->ReductionMap.lookup(D);
    if (!ReductionData.ReductionOp ||
        !ReductionData.ReductionOp.is<const Expr *>())
      return DSAVarData();
    SR = ReductionData.ReductionRange;
    ReductionRef = ReductionData.ReductionOp.get<const Expr *>();
    assert(I->TaskgroupReductionRef && "taskgroup reduction reference "
                                       "expression for the descriptor is not "
                                       "set.");
    TaskgroupDescriptor = I->TaskgroupReductionRef;
    return DSAVarData(I->Directive, OMPC_reduction, Data.RefExpr.getPointer(),
                      Data.PrivateCopy, I->DefaultAttrLoc, OMPC_REDUCTION_task,
                      /*AppliedToPointee=*/false);
  }
  return DSAVarData();
}
 
bool DSAStackTy::isOpenMPLocal(VarDecl *D, const_iterator I) const {
  D = D->getCanonicalDecl();
  for (const_iterator E = end(); I != E; ++I) {
    if (isImplicitOrExplicitTaskingRegion(I->Directive) ||
        isOpenMPTargetExecutionDirective(I->Directive)) {
      if (I->CurScope) {
        Scope *TopScope = I->CurScope->getParent();
        Scope *CurScope = getCurScope();
        while (CurScope && CurScope != TopScope && !CurScope->isDeclScope(D))
          CurScope = CurScope->getParent();
        return CurScope != TopScope;
      }
      for (DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent())
        if (I->Context == DC)
          return true;
      return false;
    }
  }
  return false;
}
 
static bool isConstNotMutableType(Sema &SemaRef, QualType Type,
                                  bool AcceptIfMutable = true,
                                  bool *IsClassType = nullptr) {
  ASTContext &Context = SemaRef.getASTContext();
  Type = Type.getNonReferenceType().getCanonicalType();
  bool IsConstant = Type.isConstant(Context);
  Type = Context.getBaseElementType(Type);
  const CXXRecordDecl *RD = AcceptIfMutable && SemaRef.getLangOpts().CPlusPlus
                                ? Type->getAsCXXRecordDecl()
                                : nullptr;
  if (const auto *CTSD = dyn_cast_or_null<ClassTemplateSpecializationDecl>(RD))
    if (const ClassTemplateDecl *CTD = CTSD->getSpecializedTemplate())
      RD = CTD->getTemplatedDecl();
  if (IsClassType)
    *IsClassType = RD;
  return IsConstant && !(SemaRef.getLangOpts().CPlusPlus && RD &&
                         RD->hasDefinition() && RD->hasMutableFields());
}
 
static bool rejectConstNotMutableType(Sema &SemaRef, const ValueDecl *D,
                                      QualType Type, OpenMPClauseKind CKind,
                                      SourceLocation ELoc,
                                      bool AcceptIfMutable = true,
                                      bool ListItemNotVar = false) {
  ASTContext &Context = SemaRef.getASTContext();
  bool IsClassType;
  if (isConstNotMutableType(SemaRef, Type, AcceptIfMutable, &IsClassType)) {
    unsigned Diag = ListItemNotVar ? diag::err_omp_const_list_item
                    : IsClassType  ? diag::err_omp_const_not_mutable_variable
                                   : diag::err_omp_const_variable;
    SemaRef.Diag(ELoc, Diag) << getOpenMPClauseName(CKind);
    if (!ListItemNotVar && D) {
      const VarDecl *VD = dyn_cast<VarDecl>(D);
      bool IsDecl = !VD || VD->isThisDeclarationADefinition(Context) ==
                               VarDecl::DeclarationOnly;
      SemaRef.Diag(D->getLocation(),
                   IsDecl ? diag::note_previous_decl : diag::note_defined_here)
          << D;
    }
    return true;
  }
  return false;
}
 
const DSAStackTy::DSAVarData DSAStackTy::getTopDSA(ValueDecl *D,
                                                   bool FromParent) {
  D = getCanonicalDecl(D);
  DSAVarData DVar;
 
  auto *VD = dyn_cast<VarDecl>(D);
  auto TI = Threadprivates.find(D);
  if (TI != Threadprivates.end()) {
    DVar.RefExpr = TI->getSecond().RefExpr.getPointer();
    DVar.CKind = OMPC_threadprivate;
    DVar.Modifier = TI->getSecond().Modifier;
    return DVar;
  }
  if (VD && VD->hasAttr<OMPThreadPrivateDeclAttr>()) {
    DVar.RefExpr = buildDeclRefExpr(
        SemaRef, VD, D->getType().getNonReferenceType(),
        VD->getAttr<OMPThreadPrivateDeclAttr>()->getLocation());
    DVar.CKind = OMPC_threadprivate;
    addDSA(D, DVar.RefExpr, OMPC_threadprivate);
    return DVar;
  }
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  //  Variables appearing in threadprivate directives are threadprivate.
  if ((VD && VD->getTLSKind() != VarDecl::TLS_None &&
       !(VD->hasAttr<OMPThreadPrivateDeclAttr>() &&
         SemaRef.getLangOpts().OpenMPUseTLS &&
         SemaRef.getASTContext().getTargetInfo().isTLSSupported())) ||
      (VD && VD->getStorageClass() == SC_Register &&
       VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())) {
    DVar.RefExpr = buildDeclRefExpr(
        SemaRef, VD, D->getType().getNonReferenceType(), D->getLocation());
    DVar.CKind = OMPC_threadprivate;
    addDSA(D, DVar.RefExpr, OMPC_threadprivate);
    return DVar;
  }
  if (SemaRef.getLangOpts().OpenMPCUDAMode && VD &&
      VD->isLocalVarDeclOrParm() && !isStackEmpty() &&
      !isLoopControlVariable(D).first) {
    const_iterator IterTarget =
        std::find_if(begin(), end(), [](const SharingMapTy &Data) {
          return isOpenMPTargetExecutionDirective(Data.Directive);
        });
    if (IterTarget != end()) {
      const_iterator ParentIterTarget = IterTarget + 1;
      for (const_iterator Iter = begin(); Iter != ParentIterTarget; ++Iter) {
        if (isOpenMPLocal(VD, Iter)) {
          DVar.RefExpr =
              buildDeclRefExpr(SemaRef, VD, D->getType().getNonReferenceType(),
                               D->getLocation());
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
      }
      if (!isClauseParsingMode() || IterTarget != begin()) {
        auto DSAIter = IterTarget->SharingMap.find(D);
        if (DSAIter != IterTarget->SharingMap.end() &&
            isOpenMPPrivate(DSAIter->getSecond().Attributes)) {
          DVar.RefExpr = DSAIter->getSecond().RefExpr.getPointer();
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
        const_iterator End = end();
        if (!SemaRef.isOpenMPCapturedByRef(D,
                                           std::distance(ParentIterTarget, End),
                                           /*OpenMPCaptureLevel=*/0)) {
          DVar.RefExpr =
              buildDeclRefExpr(SemaRef, VD, D->getType().getNonReferenceType(),
                               IterTarget->ConstructLoc);
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
      }
    }
  }
 
  if (isStackEmpty())
    // Not in OpenMP execution region and top scope was already checked.
    return DVar;
 
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.4]
  //  Static data members are shared.
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.7]
  //  Variables with static storage duration that are declared in a scope
  //  inside the construct are shared.
  if (VD && VD->isStaticDataMember()) {
    // Check for explicitly specified attributes.
    const_iterator I = begin();
    const_iterator EndI = end();
    if (FromParent && I != EndI)
      ++I;
    if (I != EndI) {
      auto It = I->SharingMap.find(D);
      if (It != I->SharingMap.end()) {
        const DSAInfo &Data = It->getSecond();
        DVar.RefExpr = Data.RefExpr.getPointer();
        DVar.PrivateCopy = Data.PrivateCopy;
        DVar.CKind = Data.Attributes;
        DVar.ImplicitDSALoc = I->DefaultAttrLoc;
        DVar.DKind = I->Directive;
        DVar.Modifier = Data.Modifier;
        DVar.AppliedToPointee = Data.AppliedToPointee;
        return DVar;
      }
    }
 
    DVar.CKind = OMPC_shared;
    return DVar;
  }
 
  auto &&MatchesAlways = [](OpenMPDirectiveKind) { return true; };
  // The predetermined shared attribute for const-qualified types having no
  // mutable members was removed after OpenMP 3.1.
  if (SemaRef.LangOpts.OpenMP <= 31) {
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, C/C++, predetermined, p.6]
    //  Variables with const qualified type having no mutable member are
    //  shared.
    if (isConstNotMutableType(SemaRef, D->getType())) {
      // Variables with const-qualified type having no mutable member may be
      // listed in a firstprivate clause, even if they are static data members.
      DSAVarData DVarTemp = hasInnermostDSA(
          D,
          [](OpenMPClauseKind C, bool) {
            return C == OMPC_firstprivate || C == OMPC_shared;
          },
          MatchesAlways, FromParent);
      if (DVarTemp.CKind != OMPC_unknown && DVarTemp.RefExpr)
        return DVarTemp;
 
      DVar.CKind = OMPC_shared;
      return DVar;
    }
  }
 
  // Explicitly specified attributes and local variables with predetermined
  // attributes.
  const_iterator I = begin();
  const_iterator EndI = end();
  if (FromParent && I != EndI)
    ++I;
  if (I == EndI)
    return DVar;
  auto It = I->SharingMap.find(D);
  if (It != I->SharingMap.end()) {
    const DSAInfo &Data = It->getSecond();
    DVar.RefExpr = Data.RefExpr.getPointer();
    DVar.PrivateCopy = Data.PrivateCopy;
    DVar.CKind = Data.Attributes;
    DVar.ImplicitDSALoc = I->DefaultAttrLoc;
    DVar.DKind = I->Directive;
    DVar.Modifier = Data.Modifier;
    DVar.AppliedToPointee = Data.AppliedToPointee;
  }
 
  return DVar;
}
 
const DSAStackTy::DSAVarData DSAStackTy::getImplicitDSA(ValueDecl *D,
                                                        bool FromParent) const {
  if (isStackEmpty()) {
    const_iterator I;
    return getDSA(I, D);
  }
  D = getCanonicalDecl(D);
  const_iterator StartI = begin();
  const_iterator EndI = end();
  if (FromParent && StartI != EndI)
    ++StartI;
  return getDSA(StartI, D);
}
 
const DSAStackTy::DSAVarData DSAStackTy::getImplicitDSA(ValueDecl *D,
                                                        unsigned Level) const {
  if (getStackSize() <= Level)
    return DSAVarData();
  D = getCanonicalDecl(D);
  const_iterator StartI = std::next(begin(), getStackSize() - 1 - Level);
  return getDSA(StartI, D);
}
 
const DSAStackTy::DSAVarData
DSAStackTy::hasDSA(ValueDecl *D,
                   const llvm::function_ref<bool(OpenMPClauseKind, bool,
                                                 DefaultDataSharingAttributes)>
                       CPred,
                   const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
                   bool FromParent) const {
  if (isStackEmpty())
    return {};
  D = getCanonicalDecl(D);
  const_iterator I = begin();
  const_iterator EndI = end();
  if (FromParent && I != EndI)
    ++I;
  for (; I != EndI; ++I) {
    if (!DPred(I->Directive) &&
        !isImplicitOrExplicitTaskingRegion(I->Directive))
      continue;
    const_iterator NewI = I;
    DSAVarData DVar = getDSA(NewI, D);
    if (I == NewI && CPred(DVar.CKind, DVar.AppliedToPointee, I->DefaultAttr))
      return DVar;
  }
  return {};
}
 
const DSAStackTy::DSAVarData DSAStackTy::hasInnermostDSA(
    ValueDecl *D, const llvm::function_ref<bool(OpenMPClauseKind, bool)> CPred,
    const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
    bool FromParent) const {
  if (isStackEmpty())
    return {};
  D = getCanonicalDecl(D);
  const_iterator StartI = begin();
  const_iterator EndI = end();
  if (FromParent && StartI != EndI)
    ++StartI;
  if (StartI == EndI || !DPred(StartI->Directive))
    return {};
  const_iterator NewI = StartI;
  DSAVarData DVar = getDSA(NewI, D);
  return (NewI == StartI && CPred(DVar.CKind, DVar.AppliedToPointee))
             ? DVar
             : DSAVarData();
}
 
bool DSAStackTy::hasExplicitDSA(
    const ValueDecl *D,
    const llvm::function_ref<bool(OpenMPClauseKind, bool)> CPred,
    unsigned Level, bool NotLastprivate) const {
  if (getStackSize() <= Level)
    return false;
  D = getCanonicalDecl(D);
  const SharingMapTy &StackElem = getStackElemAtLevel(Level);
  auto I = StackElem.SharingMap.find(D);
  if (I != StackElem.SharingMap.end() && I->getSecond().RefExpr.getPointer() &&
      CPred(I->getSecond().Attributes, I->getSecond().AppliedToPointee) &&
      (!NotLastprivate || !I->getSecond().RefExpr.getInt()))
    return true;
  // Check predetermined rules for the loop control variables.
  auto LI = StackElem.LCVMap.find(D);
  if (LI != StackElem.LCVMap.end())
    return CPred(OMPC_private, /*AppliedToPointee=*/false);
  return false;
}
 
bool DSAStackTy::hasExplicitDirective(
    const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
    unsigned Level) const {
  if (getStackSize() <= Level)
    return false;
  const SharingMapTy &StackElem = getStackElemAtLevel(Level);
  return DPred(StackElem.Directive);
}
 
bool DSAStackTy::hasDirective(
    const llvm::function_ref<bool(OpenMPDirectiveKind,
                                  const DeclarationNameInfo &, SourceLocation)>
        DPred,
    bool FromParent) const {
  // We look only in the enclosing region.
  size_t Skip = FromParent ? 2 : 1;
  for (const_iterator I = begin() + std::min(Skip, getStackSize()), E = end();
       I != E; ++I) {
    if (DPred(I->Directive, I->DirectiveName, I->ConstructLoc))
      return true;
  }
  return false;
}
 
void Sema::InitDataSharingAttributesStack() {
  VarDataSharingAttributesStack = new DSAStackTy(*this);
}
 
#define DSAStack static_cast<DSAStackTy *>(VarDataSharingAttributesStack)
 
void Sema::pushOpenMPFunctionRegion() { DSAStack->pushFunction(); }
 
void Sema::popOpenMPFunctionRegion(const FunctionScopeInfo *OldFSI) {
  DSAStack->popFunction(OldFSI);
}
 
static bool isOpenMPDeviceDelayedContext(Sema &S) {
  assert(S.LangOpts.OpenMP && S.LangOpts.OpenMPIsDevice &&
         "Expected OpenMP device compilation.");
  return !S.isInOpenMPTargetExecutionDirective();
}
 
namespace {
/// Status of the function emission on the host/device.
enum class FunctionEmissionStatus {
  Emitted,
  Discarded,
  Unknown,
};
} // anonymous namespace
 
Sema::SemaDiagnosticBuilder Sema::diagIfOpenMPDeviceCode(SourceLocation Loc,
                                                         unsigned DiagID,
                                                         FunctionDecl *FD) {
  assert(LangOpts.OpenMP && LangOpts.OpenMPIsDevice &&
         "Expected OpenMP device compilation.");
 
  SemaDiagnosticBuilder::Kind Kind = SemaDiagnosticBuilder::K_Nop;
  if (FD) {
    FunctionEmissionStatus FES = getEmissionStatus(FD);
    switch (FES) {
    case FunctionEmissionStatus::Emitted:
      Kind = SemaDiagnosticBuilder::K_Immediate;
      break;
    case FunctionEmissionStatus::Unknown:
      // TODO: We should always delay diagnostics here in case a target
      //       region is in a function we do not emit. However, as the
      //       current diagnostics are associated with the function containing
      //       the target region and we do not emit that one, we would miss out
      //       on diagnostics for the target region itself. We need to anchor
      //       the diagnostics with the new generated function *or* ensure we
      //       emit diagnostics associated with the surrounding function.
      Kind = isOpenMPDeviceDelayedContext(*this)
                 ? SemaDiagnosticBuilder::K_Deferred
                 : SemaDiagnosticBuilder::K_Immediate;
      break;
    case FunctionEmissionStatus::TemplateDiscarded:
    case FunctionEmissionStatus::OMPDiscarded:
      Kind = SemaDiagnosticBuilder::K_Nop;
      break;
    case FunctionEmissionStatus::CUDADiscarded:
      llvm_unreachable("CUDADiscarded unexpected in OpenMP device compilation");
      break;
    }
  }
 
  return SemaDiagnosticBuilder(Kind, Loc, DiagID, FD, *this);
}
 
Sema::SemaDiagnosticBuilder Sema::diagIfOpenMPHostCode(SourceLocation Loc,
                                                       unsigned DiagID,
                                                       FunctionDecl *FD) {
  assert(LangOpts.OpenMP && !LangOpts.OpenMPIsDevice &&
         "Expected OpenMP host compilation.");
 
  SemaDiagnosticBuilder::Kind Kind = SemaDiagnosticBuilder::K_Nop;
  if (FD) {
    FunctionEmissionStatus FES = getEmissionStatus(FD);
    switch (FES) {
    case FunctionEmissionStatus::Emitted:
      Kind = SemaDiagnosticBuilder::K_Immediate;
      break;
    case FunctionEmissionStatus::Unknown:
      Kind = SemaDiagnosticBuilder::K_Deferred;
      break;
    case FunctionEmissionStatus::TemplateDiscarded:
    case FunctionEmissionStatus::OMPDiscarded:
    case FunctionEmissionStatus::CUDADiscarded:
      Kind = SemaDiagnosticBuilder::K_Nop;
      break;
    }
  }
 
  return SemaDiagnosticBuilder(Kind, Loc, DiagID, FD, *this);
}
 
static OpenMPDefaultmapClauseKind
getVariableCategoryFromDecl(const LangOptions &LO, const ValueDecl *VD) {
  if (LO.OpenMP <= 45) {
    if (VD->getType().getNonReferenceType()->isScalarType())
      return OMPC_DEFAULTMAP_scalar;
    return OMPC_DEFAULTMAP_aggregate;
  }
  if (VD->getType().getNonReferenceType()->isAnyPointerType())
    return OMPC_DEFAULTMAP_pointer;
  if (VD->getType().getNonReferenceType()->isScalarType())
    return OMPC_DEFAULTMAP_scalar;
  return OMPC_DEFAULTMAP_aggregate;
}
 
bool Sema::isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level,
                                 unsigned OpenMPCaptureLevel) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
 
  ASTContext &Ctx = getASTContext();
  bool IsByRef = true;
 
  // Find the directive that is associated with the provided scope.
  D = cast<ValueDecl>(D->getCanonicalDecl());
  QualType Ty = D->getType();
 
  bool IsVariableUsedInMapClause = false;
  if (DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective, Level)) {
    // This table summarizes how a given variable should be passed to the device
    // given its type and the clauses where it appears. This table is based on
    // the description in OpenMP 4.5 [2.10.4, target Construct] and
    // OpenMP 4.5 [2.15.5, Data-mapping Attribute Rules and Clauses].
    //
    // =========================================================================
    // | type |  defaultmap   | pvt | first | is_device_ptr |    map   | res.  |
    // |      |(tofrom:scalar)|     |  pvt  |               |has_dv_adr|       |
    // =========================================================================
    // | scl  |               |     |       |       -       |          | bycopy|
    // | scl  |               |  -  |   x   |       -       |     -    | bycopy|
    // | scl  |               |  x  |   -   |       -       |     -    | null  |
    // | scl  |       x       |     |       |       -       |          | byref |
    // | scl  |       x       |  -  |   x   |       -       |     -    | bycopy|
    // | scl  |       x       |  x  |   -   |       -       |     -    | null  |
    // | scl  |               |  -  |   -   |       -       |     x    | byref |
    // | scl  |       x       |  -  |   -   |       -       |     x    | byref |
    //
    // | agg  |      n.a.     |     |       |       -       |          | byref |
    // | agg  |      n.a.     |  -  |   x   |       -       |     -    | byref |
    // | agg  |      n.a.     |  x  |   -   |       -       |     -    | null  |
    // | agg  |      n.a.     |  -  |   -   |       -       |     x    | byref |
    // | agg  |      n.a.     |  -  |   -   |       -       |    x[]   | byref |
    //
    // | ptr  |      n.a.     |     |       |       -       |          | bycopy|
    // | ptr  |      n.a.     |  -  |   x   |       -       |     -    | bycopy|
    // | ptr  |      n.a.     |  x  |   -   |       -       |     -    | null  |
    // | ptr  |      n.a.     |  -  |   -   |       -       |     x    | byref |
    // | ptr  |      n.a.     |  -  |   -   |       -       |    x[]   | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |          | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |     x    | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |    x[]   | bycopy|
    // =========================================================================
    // Legend:
    //  scl - scalar
    //  ptr - pointer
    //  agg - aggregate
    //  x - applies
    //  - - invalid in this combination
    //  [] - mapped with an array section
    //  byref - should be mapped by reference
    //  byval - should be mapped by value
    //  null - initialize a local variable to null on the device
    //
    // Observations:
    //  - All scalar declarations that show up in a map clause have to be passed
    //    by reference, because they may have been mapped in the enclosing data
    //    environment.
    //  - If the scalar value does not fit the size of uintptr, it has to be
    //    passed by reference, regardless the result in the table above.
    //  - For pointers mapped by value that have either an implicit map or an
    //    array section, the runtime library may pass the NULL value to the
    //    device instead of the value passed to it by the compiler.
 
    if (Ty->isReferenceType())
      Ty = Ty->castAs<ReferenceType>()->getPointeeType();
 
    // Locate map clauses and see if the variable being captured is referred to
    // in any of those clauses. Here we only care about variables, not fields,
    // because fields are part of aggregates.
    bool IsVariableAssociatedWithSection = false;
 
    DSAStack->checkMappableExprComponentListsForDeclAtLevel(
        D, Level,
        [&IsVariableUsedInMapClause, &IsVariableAssociatedWithSection,
         D](OMPClauseMappableExprCommon::MappableExprComponentListRef
                MapExprComponents,
            OpenMPClauseKind WhereFoundClauseKind) {
          // Both map and has_device_addr clauses information influences how a
          // variable is captured. E.g. is_device_ptr does not require changing
          // the default behavior.
          if (WhereFoundClauseKind != OMPC_map &&
              WhereFoundClauseKind != OMPC_has_device_addr)
            return false;
 
          auto EI = MapExprComponents.rbegin();
          auto EE = MapExprComponents.rend();
 
          assert(EI != EE && "Invalid map expression!");
 
          if (isa<DeclRefExpr>(EI->getAssociatedExpression()))
            IsVariableUsedInMapClause |= EI->getAssociatedDeclaration() == D;
 
          ++EI;
          if (EI == EE)
            return false;
 
          if (isa<ArraySubscriptExpr>(EI->getAssociatedExpression()) ||
              isa<OMPArraySectionExpr>(EI->getAssociatedExpression()) ||
              isa<MemberExpr>(EI->getAssociatedExpression()) ||
              isa<OMPArrayShapingExpr>(EI->getAssociatedExpression())) {
            IsVariableAssociatedWithSection = true;
            // There is nothing more we need to know about this variable.
            return true;
          }
 
          // Keep looking for more map info.
          return false;
        });
 
    if (IsVariableUsedInMapClause) {
      // If variable is identified in a map clause it is always captured by
      // reference except if it is a pointer that is dereferenced somehow.
      IsByRef = !(Ty->isPointerType() && IsVariableAssociatedWithSection);
    } else {
      // By default, all the data that has a scalar type is mapped by copy
      // (except for reduction variables).
      // Defaultmap scalar is mutual exclusive to defaultmap pointer
      IsByRef = (DSAStack->isForceCaptureByReferenceInTargetExecutable() &&
                 !Ty->isAnyPointerType()) ||
                !Ty->isScalarType() ||
                DSAStack->isDefaultmapCapturedByRef(
                    Level, getVariableCategoryFromDecl(LangOpts, D)) ||
                DSAStack->hasExplicitDSA(
                    D,
                    [](OpenMPClauseKind K, bool AppliedToPointee) {
                      return K == OMPC_reduction && !AppliedToPointee;
                    },
                    Level);
    }
  }
 
  if (IsByRef && Ty.getNonReferenceType()->isScalarType()) {
    IsByRef =
        ((IsVariableUsedInMapClause &&
          DSAStack->getCaptureRegion(Level, OpenMPCaptureLevel) ==
              OMPD_target) ||
         !(DSAStack->hasExplicitDSA(
               D,
               [](OpenMPClauseKind K, bool AppliedToPointee) -> bool {
                 return K == OMPC_firstprivate ||
                        (K == OMPC_reduction && AppliedToPointee);
               },
               Level, /*NotLastprivate=*/true) ||
           DSAStack->isUsesAllocatorsDecl(Level, D))) &&
        // If the variable is artificial and must be captured by value - try to
        // capture by value.
        !(isa<OMPCapturedExprDecl>(D) && !D->hasAttr<OMPCaptureNoInitAttr>() &&
          !cast<OMPCapturedExprDecl>(D)->getInit()->isGLValue()) &&
        // If the variable is implicitly firstprivate and scalar - capture by
        // copy
        !((DSAStack->getDefaultDSA() == DSA_firstprivate ||
           DSAStack->getDefaultDSA() == DSA_private) &&
          !DSAStack->hasExplicitDSA(
              D, [](OpenMPClauseKind K, bool) { return K != OMPC_unknown; },
              Level) &&
          !DSAStack->isLoopControlVariable(D, Level).first);
  }
 
  // When passing data by copy, we need to make sure it fits the uintptr size
  // and alignment, because the runtime library only deals with uintptr types.
  // If it does not fit the uintptr size, we need to pass the data by reference
  // instead.
  if (!IsByRef &&
      (Ctx.getTypeSizeInChars(Ty) >
           Ctx.getTypeSizeInChars(Ctx.getUIntPtrType()) ||
       Ctx.getDeclAlign(D) > Ctx.getTypeAlignInChars(Ctx.getUIntPtrType()))) {
    IsByRef = true;
  }
 
  return IsByRef;
}
 
unsigned Sema::getOpenMPNestingLevel() const {
  assert(getLangOpts().OpenMP);
  return DSAStack->getNestingLevel();
}
 
bool Sema::isInOpenMPTaskUntiedContext() const {
  return isOpenMPTaskingDirective(DSAStack->getCurrentDirective()) &&
         DSAStack->isUntiedRegion();
}
 
bool Sema::isInOpenMPTargetExecutionDirective() const {
  return (isOpenMPTargetExecutionDirective(DSAStack->getCurrentDirective()) &&
          !DSAStack->isClauseParsingMode()) ||
         DSAStack->hasDirective(
             [](OpenMPDirectiveKind K, const DeclarationNameInfo &,
                SourceLocation) -> bool {
               return isOpenMPTargetExecutionDirective(K);
             },
             false);
}
 
bool Sema::isOpenMPRebuildMemberExpr(ValueDecl *D) {
  // Only rebuild for Field.
  if (!dyn_cast<FieldDecl>(D))
    return false;
  DSAStackTy::DSAVarData DVarPrivate = DSAStack->hasDSA(
      D,
      [](OpenMPClauseKind C, bool AppliedToPointee,
         DefaultDataSharingAttributes DefaultAttr) {
        return isOpenMPPrivate(C) && !AppliedToPointee &&
               (DefaultAttr == DSA_firstprivate || DefaultAttr == DSA_private);
      },
      [](OpenMPDirectiveKind) { return true; },
      DSAStack->isClauseParsingMode());
  if (DVarPrivate.CKind != OMPC_unknown)
    return true;
  return false;
}
 
static OMPCapturedExprDecl *buildCaptureDecl(Sema &S, IdentifierInfo *Id,
                                             Expr *CaptureExpr, bool WithInit,
                                             DeclContext *CurContext,
                                             bool AsExpression);
 
VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D, bool CheckScopeInfo,
                                    unsigned StopAt) {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  D = getCanonicalDecl(D);
 
  auto *VD = dyn_cast<VarDecl>(D);
  // Do not capture constexpr variables.
  if (VD && VD->isConstexpr())
    return nullptr;
 
  // If we want to determine whether the variable should be captured from the
  // perspective of the current capturing scope, and we've already left all the
  // capturing scopes of the top directive on the stack, check from the
  // perspective of its parent directive (if any) instead.
  DSAStackTy::ParentDirectiveScope InParentDirectiveRAII(
      *DSAStack, CheckScopeInfo && DSAStack->isBodyComplete());
 
  // If we are attempting to capture a global variable in a directive with
  // 'target' we return true so that this global is also mapped to the device.
  //
  if (VD && !VD->hasLocalStorage() &&
      (getCurCapturedRegion() || getCurBlock() || getCurLambda())) {
    if (isInOpenMPTargetExecutionDirective()) {
      DSAStackTy::DSAVarData DVarTop =
          DSAStack->getTopDSA(D, DSAStack->isClauseParsingMode());
      if (DVarTop.CKind != OMPC_unknown && DVarTop.RefExpr)
        return VD;
      // If the declaration is enclosed in a 'declare target' directive,
      // then it should not be captured.
      //
      if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
        return nullptr;
      CapturedRegionScopeInfo *CSI = nullptr;
      for (FunctionScopeInfo *FSI : llvm::drop_begin(
               llvm::reverse(FunctionScopes),
               CheckScopeInfo ? (FunctionScopes.size() - (StopAt + 1)) : 0)) {
        if (!isa<CapturingScopeInfo>(FSI))
          return nullptr;
        if (auto *RSI = dyn_cast<CapturedRegionScopeInfo>(FSI))
          if (RSI->CapRegionKind == CR_OpenMP) {
            CSI = RSI;
            break;
          }
      }
      assert(CSI && "Failed to find CapturedRegionScopeInfo");
      SmallVector<OpenMPDirectiveKind, 4> Regions;
      getOpenMPCaptureRegions(Regions,
                              DSAStack->getDirective(CSI->OpenMPLevel));
      if (Regions[CSI->OpenMPCaptureLevel] != OMPD_task)
        return VD;
    }
    if (isInOpenMPDeclareTargetContext()) {
      // Try to mark variable as declare target if it is used in capturing
      // regions.
      if (LangOpts.OpenMP <= 45 &&
          !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
        checkDeclIsAllowedInOpenMPTarget(nullptr, VD);
      return nullptr;
    }
  }
 
  if (CheckScopeInfo) {
    bool OpenMPFound = false;
    for (unsigned I = StopAt + 1; I > 0; --I) {
      FunctionScopeInfo *FSI = FunctionScopes[I - 1];
      if (!isa<CapturingScopeInfo>(FSI))
        return nullptr;
      if (auto *RSI = dyn_cast<CapturedRegionScopeInfo>(FSI))
        if (RSI->CapRegionKind == CR_OpenMP) {
          OpenMPFound = true;
          break;
        }
    }
    if (!OpenMPFound)
      return nullptr;
  }
 
  if (DSAStack->getCurrentDirective() != OMPD_unknown &&
      (!DSAStack->isClauseParsingMode() ||
       DSAStack->getParentDirective() != OMPD_unknown)) {
    auto &&Info = DSAStack->isLoopControlVariable(D);
    if (Info.first ||
        (VD && VD->hasLocalStorage() &&
         isImplicitOrExplicitTaskingRegion(DSAStack->getCurrentDirective())) ||
        (VD && DSAStack->isForceVarCapturing()))
      return VD ? VD : Info.second;
    DSAStackTy::DSAVarData DVarTop =
        DSAStack->getTopDSA(D, DSAStack->isClauseParsingMode());
    if (DVarTop.CKind != OMPC_unknown && isOpenMPPrivate(DVarTop.CKind) &&
        (!VD || VD->hasLocalStorage() || !DVarTop.AppliedToPointee))
      return VD ? VD : cast<VarDecl>(DVarTop.PrivateCopy->getDecl());
    // Threadprivate variables must not be captured.
    if (isOpenMPThreadPrivate(DVarTop.CKind))
      return nullptr;
    // The variable is not private or it is the variable in the directive with
    // default(none) clause and not used in any clause.
    DSAStackTy::DSAVarData DVarPrivate = DSAStack->hasDSA(
        D,
        [](OpenMPClauseKind C, bool AppliedToPointee, bool) {
          return isOpenMPPrivate(C) && !AppliedToPointee;
        },
        [](OpenMPDirectiveKind) { return true; },
        DSAStack->isClauseParsingMode());
    // Global shared must not be captured.
    if (VD && !VD->hasLocalStorage() && DVarPrivate.CKind == OMPC_unknown &&
        ((DSAStack->getDefaultDSA() != DSA_none &&
          DSAStack->getDefaultDSA() != DSA_private &&
          DSAStack->getDefaultDSA() != DSA_firstprivate) ||
         DVarTop.CKind == OMPC_shared))
      return nullptr;
    auto *FD = dyn_cast<FieldDecl>(D);
    if (DVarPrivate.CKind != OMPC_unknown && !VD && FD &&
        !DVarPrivate.PrivateCopy) {
      DSAStackTy::DSAVarData DVarPrivate = DSAStack->hasDSA(
          D,
          [](OpenMPClauseKind C, bool AppliedToPointee,
             DefaultDataSharingAttributes DefaultAttr) {
            return isOpenMPPrivate(C) && !AppliedToPointee &&
                   (DefaultAttr == DSA_firstprivate ||
                    DefaultAttr == DSA_private);
          },
          [](OpenMPDirectiveKind) { return true; },
          DSAStack->isClauseParsingMode());
      if (DVarPrivate.CKind == OMPC_unknown)
        return nullptr;
 
      VarDecl *VD = DSAStack->getImplicitFDCapExprDecl(FD);
      if (VD)
        return VD;
      if (getCurrentThisType().isNull())
        return nullptr;
      Expr *ThisExpr = BuildCXXThisExpr(SourceLocation(), getCurrentThisType(),
                                        /*IsImplicit=*/true);
      const CXXScopeSpec CS = CXXScopeSpec();
      Expr *ME = BuildMemberExpr(ThisExpr, /*IsArrow=*/true, SourceLocation(),
                                 NestedNameSpecifierLoc(), SourceLocation(), FD,
                                 DeclAccessPair::make(FD, FD->getAccess()),
                                 /*HadMultipleCandidates=*/false,
                                 DeclarationNameInfo(), FD->getType(),
                                 VK_LValue, OK_Ordinary);
      OMPCapturedExprDecl *CD = buildCaptureDecl(
          *this, FD->getIdentifier(), ME, DVarPrivate.CKind != OMPC_private,
          CurContext->getParent(), /*AsExpression=*/false);
      DeclRefExpr *VDPrivateRefExpr = buildDeclRefExpr(
          *this, CD, CD->getType().getNonReferenceType(), SourceLocation());
      VD = cast<VarDecl>(VDPrivateRefExpr->getDecl());
      DSAStack->addImplicitDefaultFirstprivateFD(FD, VD);
      return VD;
    }
    if (DVarPrivate.CKind != OMPC_unknown ||
        (VD && (DSAStack->getDefaultDSA() == DSA_none ||
                DSAStack->getDefaultDSA() == DSA_private ||
                DSAStack->getDefaultDSA() == DSA_firstprivate)))
      return VD ? VD : cast<VarDecl>(DVarPrivate.PrivateCopy->getDecl());
  }
  return nullptr;
}
 
void Sema::adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
                                        unsigned Level) const {
  FunctionScopesIndex -= getOpenMPCaptureLevels(DSAStack->getDirective(Level));
}
 
void Sema::startOpenMPLoop() {
  assert(LangOpts.OpenMP && "OpenMP must be enabled.");
  if (isOpenMPLoopDirective(DSAStack->getCurrentDirective()))
    DSAStack->loopInit();
}
 
void Sema::startOpenMPCXXRangeFor() {
  assert(LangOpts.OpenMP && "OpenMP must be enabled.");
  if (isOpenMPLoopDirective(DSAStack->getCurrentDirective())) {
    DSAStack->resetPossibleLoopCounter();
    DSAStack->loopStart();
  }
}
 
OpenMPClauseKind Sema::isOpenMPPrivateDecl(ValueDecl *D, unsigned Level,
                                           unsigned CapLevel) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  if (DSAStack->getCurrentDirective() != OMPD_unknown &&
      (!DSAStack->isClauseParsingMode() ||
       DSAStack->getParentDirective() != OMPD_unknown)) {
    DSAStackTy::DSAVarData DVarPrivate = DSAStack->hasDSA(
        D,
        [](OpenMPClauseKind C, bool AppliedToPointee,
           DefaultDataSharingAttributes DefaultAttr) {
          return isOpenMPPrivate(C) && !AppliedToPointee &&
                 DefaultAttr == DSA_private;
        },
        [](OpenMPDirectiveKind) { return true; },
        DSAStack->isClauseParsingMode());
    if (DVarPrivate.CKind == OMPC_private && isa<OMPCapturedExprDecl>(D) &&
        DSAStack->isImplicitDefaultFirstprivateFD(cast<VarDecl>(D)) &&
        !DSAStack->isLoopControlVariable(D).first)
      return OMPC_private;
  }
  if (DSAStack->hasExplicitDirective(isOpenMPTaskingDirective, Level)) {
    bool IsTriviallyCopyable =
        D->getType().getNonReferenceType().isTriviallyCopyableType(Context) &&
        !D->getType()
             .getNonReferenceType()
             .getCanonicalType()
             ->getAsCXXRecordDecl();
    OpenMPDirectiveKind DKind = DSAStack->getDirective(Level);
    SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
    getOpenMPCaptureRegions(CaptureRegions, DKind);
    if (isOpenMPTaskingDirective(CaptureRegions[CapLevel]) &&
        (IsTriviallyCopyable ||
         !isOpenMPTaskLoopDirective(CaptureRegions[CapLevel]))) {
      if (DSAStack->hasExplicitDSA(
              D,
              [](OpenMPClauseKind K, bool) { return K == OMPC_firstprivate; },
              Level, /*NotLastprivate=*/true))
        return OMPC_firstprivate;
      DSAStackTy::DSAVarData DVar = DSAStack->getImplicitDSA(D, Level);
      if (DVar.CKind != OMPC_shared &&
          !DSAStack->isLoopControlVariable(D, Level).first && !DVar.RefExpr) {
        DSAStack->addImplicitTaskFirstprivate(Level, D);
        return OMPC_firstprivate;
      }
    }
  }
  if (isOpenMPLoopDirective(DSAStack->getCurrentDirective())) {
    if (DSAStack->getAssociatedLoops() > 0 && !DSAStack->isLoopStarted()) {
      DSAStack->resetPossibleLoopCounter(D);
      DSAStack->loopStart();
      return OMPC_private;
    }
    if ((DSAStack->getPossiblyLoopCunter() == D->getCanonicalDecl() ||
         DSAStack->isLoopControlVariable(D).first) &&
        !DSAStack->hasExplicitDSA(
            D, [](OpenMPClauseKind K, bool) { return K != OMPC_private; },
            Level) &&
        !isOpenMPSimdDirective(DSAStack->getCurrentDirective()))
      return OMPC_private;
  }
  if (const auto *VD = dyn_cast<VarDecl>(D)) {
    if (DSAStack->isThreadPrivate(const_cast<VarDecl *>(VD)) &&
        DSAStack->isForceVarCapturing() &&
        !DSAStack->hasExplicitDSA(
            D, [](OpenMPClauseKind K, bool) { return K == OMPC_copyin; },
            Level))
      return OMPC_private;
  }
  // User-defined allocators are private since they must be defined in the
  // context of target region.
  if (DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective, Level) &&
      DSAStack->isUsesAllocatorsDecl(Level, D).value_or(
          DSAStackTy::UsesAllocatorsDeclKind::AllocatorTrait) ==
          DSAStackTy::UsesAllocatorsDeclKind::UserDefinedAllocator)
    return OMPC_private;
  return (DSAStack->hasExplicitDSA(
              D, [](OpenMPClauseKind K, bool) { return K == OMPC_private; },
              Level) ||
          (DSAStack->isClauseParsingMode() &&
           DSAStack->getClauseParsingMode() == OMPC_private) ||
          // Consider taskgroup reduction descriptor variable a private
          // to avoid possible capture in the region.
          (DSAStack->hasExplicitDirective(
               [](OpenMPDirectiveKind K) {
                 return K == OMPD_taskgroup ||
                        ((isOpenMPParallelDirective(K) ||
                          isOpenMPWorksharingDirective(K)) &&
                         !isOpenMPSimdDirective(K));
               },
               Level) &&
           DSAStack->isTaskgroupReductionRef(D, Level)))
             ? OMPC_private
             : OMPC_unknown;
}
 
void Sema::setOpenMPCaptureKind(FieldDecl *FD, const ValueDecl *D,
                                unsigned Level) {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  D = getCanonicalDecl(D);
  OpenMPClauseKind OMPC = OMPC_unknown;
  for (unsigned I = DSAStack->getNestingLevel() + 1; I > Level; --I) {
    const unsigned NewLevel = I - 1;
    if (DSAStack->hasExplicitDSA(
            D,
            [&OMPC](const OpenMPClauseKind K, bool AppliedToPointee) {
              if (isOpenMPPrivate(K) && !AppliedToPointee) {
                OMPC = K;
                return true;
              }
              return false;
            },
            NewLevel))
      break;
    if (DSAStack->checkMappableExprComponentListsForDeclAtLevel(
            D, NewLevel,
            [](OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind) { return true; })) {
      OMPC = OMPC_map;
      break;
    }
    if (DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective,
                                       NewLevel)) {
      OMPC = OMPC_map;
      if (DSAStack->mustBeFirstprivateAtLevel(
              NewLevel, getVariableCategoryFromDecl(LangOpts, D)))
        OMPC = OMPC_firstprivate;
      break;
    }
  }
  if (OMPC != OMPC_unknown)
    FD->addAttr(OMPCaptureKindAttr::CreateImplicit(Context, unsigned(OMPC)));
}
 
bool Sema::isOpenMPTargetCapturedDecl(const ValueDecl *D, unsigned Level,
                                      unsigned CaptureLevel) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  // Return true if the current level is no longer enclosed in a target region.
 
  SmallVector<OpenMPDirectiveKind, 4> Regions;
  getOpenMPCaptureRegions(Regions, DSAStack->getDirective(Level));
  const auto *VD = dyn_cast<VarDecl>(D);
  return VD && !VD->hasLocalStorage() &&
         DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective,
                                        Level) &&
         Regions[CaptureLevel] != OMPD_task;
}
 
bool Sema::isOpenMPGlobalCapturedDecl(ValueDecl *D, unsigned Level,
                                      unsigned CaptureLevel) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  // Return true if the current level is no longer enclosed in a target region.
 
  if (const auto *VD = dyn_cast<VarDecl>(D)) {
    if (!VD->hasLocalStorage()) {
      if (isInOpenMPTargetExecutionDirective())
        return true;
      DSAStackTy::DSAVarData TopDVar =
          DSAStack->getTopDSA(D, /*FromParent=*/false);
      unsigned NumLevels =
          getOpenMPCaptureLevels(DSAStack->getDirective(Level));
      if (Level == 0)
        // non-file scope static variale with default(firstprivate)
        // should be gloabal captured.
        return (NumLevels == CaptureLevel + 1 &&
                (TopDVar.CKind != OMPC_shared ||
                 DSAStack->getDefaultDSA() == DSA_firstprivate));
      do {
        --Level;
        DSAStackTy::DSAVarData DVar = DSAStack->getImplicitDSA(D, Level);
        if (DVar.CKind != OMPC_shared)
          return true;
      } while (Level > 0);
    }
  }
  return true;
}
 
void Sema::DestroyDataSharingAttributesStack() { delete DSAStack; }
 
void Sema::ActOnOpenMPBeginDeclareVariant(SourceLocation Loc,
                                          OMPTraitInfo &TI) {
  OMPDeclareVariantScopes.push_back(OMPDeclareVariantScope(TI));
}
 
void Sema::ActOnOpenMPEndDeclareVariant() {
  assert(isInOpenMPDeclareVariantScope() &&
         "Not in OpenMP declare variant scope!");
 
  OMPDeclareVariantScopes.pop_back();
}
 
void Sema::finalizeOpenMPDelayedAnalysis(const FunctionDecl *Caller,
                                         const FunctionDecl *Callee,
                                         SourceLocation Loc) {
  assert(LangOpts.OpenMP && "Expected OpenMP compilation mode.");
  Optional<OMPDeclareTargetDeclAttr::DevTypeTy> DevTy =
      OMPDeclareTargetDeclAttr::getDeviceType(Caller->getMostRecentDecl());
  // Ignore host functions during device analyzis.
  if (LangOpts.OpenMPIsDevice &&
      (!DevTy || *DevTy == OMPDeclareTargetDeclAttr::DT_Host))
    return;
  // Ignore nohost functions during host analyzis.
  if (!LangOpts.OpenMPIsDevice && DevTy &&
      *DevTy == OMPDeclareTargetDeclAttr::DT_NoHost)
    return;
  const FunctionDecl *FD = Callee->getMostRecentDecl();
  DevTy = OMPDeclareTargetDeclAttr::getDeviceType(FD);
  if (LangOpts.OpenMPIsDevice && DevTy &&
      *DevTy == OMPDeclareTargetDeclAttr::DT_Host) {
    // Diagnose host function called during device codegen.
    StringRef HostDevTy =
        getOpenMPSimpleClauseTypeName(OMPC_device_type, OMPC_DEVICE_TYPE_host);
    Diag(Loc, diag::err_omp_wrong_device_function_call) << HostDevTy << 0;
    Diag(*OMPDeclareTargetDeclAttr::getLocation(FD),
         diag::note_omp_marked_device_type_here)
        << HostDevTy;
    return;
  }
  if (!LangOpts.OpenMPIsDevice && !LangOpts.OpenMPOffloadMandatory && DevTy &&
      *DevTy == OMPDeclareTargetDeclAttr::DT_NoHost) {
    // Diagnose nohost function called during host codegen.
    StringRef NoHostDevTy = getOpenMPSimpleClauseTypeName(
        OMPC_device_type, OMPC_DEVICE_TYPE_nohost);
    Diag(Loc, diag::err_omp_wrong_device_function_call) << NoHostDevTy << 1;
    Diag(*OMPDeclareTargetDeclAttr::getLocation(FD),
         diag::note_omp_marked_device_type_here)
        << NoHostDevTy;
  }
}
 
void Sema::StartOpenMPDSABlock(OpenMPDirectiveKind DKind,
                               const DeclarationNameInfo &DirName,
                               Scope *CurScope, SourceLocation Loc) {
  DSAStack->push(DKind, DirName, CurScope, Loc);
  PushExpressionEvaluationContext(
      ExpressionEvaluationContext::PotentiallyEvaluated);
}
 
void Sema::StartOpenMPClause(OpenMPClauseKind K) {
  DSAStack->setClauseParsingMode(K);
}
 
void Sema::EndOpenMPClause() {
  DSAStack->setClauseParsingMode(/*K=*/OMPC_unknown);
  CleanupVarDeclMarking();
}
 
static std::pair<ValueDecl *, bool>
getPrivateItem(Sema &S, Expr *&RefExpr, SourceLocation &ELoc,
               SourceRange &ERange, bool AllowArraySection = false,
               StringRef DiagType = "");
 
/// Check consistency of the reduction clauses.
static void checkReductionClauses(Sema &S, DSAStackTy *Stack,
                                  ArrayRef<OMPClause *> Clauses) {
  bool InscanFound = false;
  SourceLocation InscanLoc;
  // OpenMP 5.0, 2.19.5.4 reduction Clause, Restrictions.
  // A reduction clause without the inscan reduction-modifier may not appear on
  // a construct on which a reduction clause with the inscan reduction-modifier
  // appears.
  for (OMPClause *C : Clauses) {
    if (C->getClauseKind() != OMPC_reduction)
      continue;
    auto *RC = cast<OMPReductionClause>(C);
    if (RC->getModifier() == OMPC_REDUCTION_inscan) {
      InscanFound = true;
      InscanLoc = RC->getModifierLoc();
      continue;
    }
    if (RC->getModifier() == OMPC_REDUCTION_task) {
      // OpenMP 5.0, 2.19.5.4 reduction Clause.
      // A reduction clause with the task reduction-modifier may only appear on
      // a parallel construct, a worksharing construct or a combined or
      // composite construct for which any of the aforementioned constructs is a
      // constituent construct and simd or loop are not constituent constructs.
      OpenMPDirectiveKind CurDir = Stack->getCurrentDirective();
      if (!(isOpenMPParallelDirective(CurDir) ||
            isOpenMPWorksharingDirective(CurDir)) ||
          isOpenMPSimdDirective(CurDir))
        S.Diag(RC->getModifierLoc(),
               diag::err_omp_reduction_task_not_parallel_or_worksharing);
      continue;
    }
  }
  if (InscanFound) {
    for (OMPClause *C : Clauses) {
      if (C->getClauseKind() != OMPC_reduction)
        continue;
      auto *RC = cast<OMPReductionClause>(C);
      if (RC->getModifier() != OMPC_REDUCTION_inscan) {
        S.Diag(RC->getModifier() == OMPC_REDUCTION_unknown
                   ? RC->getBeginLoc()
                   : RC->getModifierLoc(),
               diag::err_omp_inscan_reduction_expected);
        S.Diag(InscanLoc, diag::note_omp_previous_inscan_reduction);
        continue;
      }
      for (Expr *Ref : RC->varlists()) {
        assert(Ref && "NULL expr in OpenMP nontemporal clause.");
        SourceLocation ELoc;
        SourceRange ERange;
        Expr *SimpleRefExpr = Ref;
        auto Res = getPrivateItem(S, SimpleRefExpr, ELoc, ERange,
                                  /*AllowArraySection=*/true);
        ValueDecl *D = Res.first;
        if (!D)
          continue;
        if (!Stack->isUsedInScanDirective(getCanonicalDecl(D))) {
          S.Diag(Ref->getExprLoc(),
                 diag::err_omp_reduction_not_inclusive_exclusive)
              << Ref->getSourceRange();
        }
      }
    }
  }
}
 
static void checkAllocateClauses(Sema &S, DSAStackTy *Stack,
                                 ArrayRef<OMPClause *> Clauses);
static DeclRefExpr *buildCapture(Sema &S, ValueDecl *D, Expr *CaptureExpr,
                                 bool WithInit);
 
static void reportOriginalDsa(Sema &SemaRef, const DSAStackTy *Stack,
                              const ValueDecl *D,
                              const DSAStackTy::DSAVarData &DVar,
                              bool IsLoopIterVar = false);
 
void Sema::EndOpenMPDSABlock(Stmt *CurDirective) {
  // OpenMP [2.14.3.5, Restrictions, C/C++, p.1]
  //  A variable of class type (or array thereof) that appears in a lastprivate
  //  clause requires an accessible, unambiguous default constructor for the
  //  class type, unless the list item is also specified in a firstprivate
  //  clause.
  if (const auto *D = dyn_cast_or_null<OMPExecutableDirective>(CurDirective)) {
    for (OMPClause *C : D->clauses()) {
      if (auto *Clause = dyn_cast<OMPLastprivateClause>(C)) {
        SmallVector<Expr *, 8> PrivateCopies;
        for (Expr *DE : Clause->varlists()) {
          if (DE->isValueDependent() || DE->isTypeDependent()) {
            PrivateCopies.push_back(nullptr);
            continue;
          }
          auto *DRE = cast<DeclRefExpr>(DE->IgnoreParens());
          auto *VD = cast<VarDecl>(DRE->getDecl());
          QualType Type = VD->getType().getNonReferenceType();
          const DSAStackTy::DSAVarData DVar =
              DSAStack->getTopDSA(VD, /*FromParent=*/false);
          if (DVar.CKind == OMPC_lastprivate) {
            // Generate helper private variable and initialize it with the
            // default value. The address of the original variable is replaced
            // by the address of the new private variable in CodeGen. This new
            // variable is not added to IdResolver, so the code in the OpenMP
            // region uses original variable for proper diagnostics.
            VarDecl *VDPrivate = buildVarDecl(
                *this, DE->getExprLoc(), Type.getUnqualifiedType(),
                VD->getName(), VD->hasAttrs() ? &VD->getAttrs() : nullptr, DRE);
            ActOnUninitializedDecl(VDPrivate);
            if (VDPrivate->isInvalidDecl()) {
              PrivateCopies.push_back(nullptr);
              continue;
            }
            PrivateCopies.push_back(buildDeclRefExpr(
                *this, VDPrivate, DE->getType(), DE->getExprLoc()));
          } else {
            // The variable is also a firstprivate, so initialization sequence
            // for private copy is generated already.
            PrivateCopies.push_back(nullptr);
          }
        }
        Clause->setPrivateCopies(PrivateCopies);
        continue;
      }
      // Finalize nontemporal clause by handling private copies, if any.
      if (auto *Clause = dyn_cast<OMPNontemporalClause>(C)) {
        SmallVector<Expr *, 8> PrivateRefs;
        for (Expr *RefExpr : Clause->varlists()) {
          assert(RefExpr && "NULL expr in OpenMP nontemporal clause.");
          SourceLocation ELoc;
          SourceRange ERange;
          Expr *SimpleRefExpr = RefExpr;
          auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange);
          if (Res.second)
            // It will be analyzed later.
            PrivateRefs.push_back(RefExpr);
          ValueDecl *D = Res.first;
          if (!D)
            continue;
 
          const DSAStackTy::DSAVarData DVar =
              DSAStack->getTopDSA(D, /*FromParent=*/false);
          PrivateRefs.push_back(DVar.PrivateCopy ? DVar.PrivateCopy
                                                 : SimpleRefExpr);
        }
        Clause->setPrivateRefs(PrivateRefs);
        continue;
      }
      if (auto *Clause = dyn_cast<OMPUsesAllocatorsClause>(C)) {
        for (unsigned I = 0, E = Clause->getNumberOfAllocators(); I < E; ++I) {
          OMPUsesAllocatorsClause::Data D = Clause->getAllocatorData(I);
          auto *DRE = dyn_cast<DeclRefExpr>(D.Allocator->IgnoreParenImpCasts());
          if (!DRE)
            continue;
          ValueDecl *VD = DRE->getDecl();
          if (!VD || !isa<VarDecl>(VD))
            continue;
          DSAStackTy::DSAVarData DVar =
              DSAStack->getTopDSA(VD, /*FromParent=*/false);
          // OpenMP [2.12.5, target Construct]
          // Memory allocators that appear in a uses_allocators clause cannot
          // appear in other data-sharing attribute clauses or data-mapping
          // attribute clauses in the same construct.
          Expr *MapExpr = nullptr;
          if (DVar.RefExpr ||
              DSAStack->checkMappableExprComponentListsForDecl(
                  VD, /*CurrentRegionOnly=*/true,
                  [VD, &MapExpr](
                      OMPClauseMappableExprCommon::MappableExprComponentListRef
                          MapExprComponents,
                      OpenMPClauseKind C) {
                    auto MI = MapExprComponents.rbegin();
                    auto ME = MapExprComponents.rend();
                    if (MI != ME &&
                        MI->getAssociatedDeclaration()->getCanonicalDecl() ==
                            VD->getCanonicalDecl()) {
                      MapExpr = MI->getAssociatedExpression();
                      return true;
                    }
                    return false;
                  })) {
            Diag(D.Allocator->getExprLoc(),
                 diag::err_omp_allocator_used_in_clauses)
                << D.Allocator->getSourceRange();
            if (DVar.RefExpr)
              reportOriginalDsa(*this, DSAStack, VD, DVar);
            else
              Diag(MapExpr->getExprLoc(), diag::note_used_here)
                  << MapExpr->getSourceRange();
          }
        }
        continue;
      }
    }
    // Check allocate clauses.
    if (!CurContext->isDependentContext())
      checkAllocateClauses(*this, DSAStack, D->clauses());
    checkReductionClauses(*this, DSAStack, D->clauses());
  }
 
  DSAStack->pop();
  DiscardCleanupsInEvaluationContext();
  PopExpressionEvaluationContext();
}
 
static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
                                     Expr *NumIterations, Sema &SemaRef,
                                     Scope *S, DSAStackTy *Stack);
 
namespace {
 
class VarDeclFilterCCC final : public CorrectionCandidateCallback {
private:
  Sema &SemaRef;
 
public:
  explicit VarDeclFilterCCC(Sema &S) : SemaRef(S) {}
  bool ValidateCandidate(const TypoCorrection &Candidate) override {
    NamedDecl *ND = Candidate.getCorrectionDecl();
    if (const auto *VD = dyn_cast_or_null<VarDecl>(ND)) {
      return VD->hasGlobalStorage() &&
             SemaRef.isDeclInScope(ND, SemaRef.getCurLexicalContext(),
                                   SemaRef.getCurScope());
    }
    return false;
  }
 
  std::unique_ptr<CorrectionCandidateCallback> clone() override {
    return std::make_unique<VarDeclFilterCCC>(*this);
  }
};
 
class VarOrFuncDeclFilterCCC final : public CorrectionCandidateCallback {
private:
  Sema &SemaRef;
 
public:
  explicit VarOrFuncDeclFilterCCC(Sema &S) : SemaRef(S) {}
  bool ValidateCandidate(const TypoCorrection &Candidate) override {
    NamedDecl *ND = Candidate.getCorrectionDecl();
    if (ND && ((isa<VarDecl>(ND) && ND->getKind() == Decl::Var) ||
               isa<FunctionDecl>(ND))) {
      return SemaRef.isDeclInScope(ND, SemaRef.getCurLexicalContext(),
                                   SemaRef.getCurScope());
    }
    return false;
  }
 
  std::unique_ptr<CorrectionCandidateCallback> clone() override {
    return std::make_unique<VarOrFuncDeclFilterCCC>(*this);
  }
};
 
} // namespace
 
ExprResult Sema::ActOnOpenMPIdExpression(Scope *CurScope,
                                         CXXScopeSpec &ScopeSpec,
                                         const DeclarationNameInfo &Id,
                                         OpenMPDirectiveKind Kind) {
  LookupResult Lookup(*this, Id, LookupOrdinaryName);
  LookupParsedName(Lookup, CurScope, &ScopeSpec, true);
 
  if (Lookup.isAmbiguous())
    return ExprError();
 
  VarDecl *VD;
  if (!Lookup.isSingleResult()) {
    VarDeclFilterCCC CCC(*this);
    if (TypoCorrection Corrected =
            CorrectTypo(Id, LookupOrdinaryName, CurScope, nullptr, CCC,
                        CTK_ErrorRecovery)) {
      diagnoseTypo(Corrected,
                   PDiag(Lookup.empty()
                             ? diag::err_undeclared_var_use_suggest
                             : diag::err_omp_expected_var_arg_suggest)
                       << Id.getName());
      VD = Corrected.getCorrectionDeclAs<VarDecl>();
    } else {
      Diag(Id.getLoc(), Lookup.empty() ? diag::err_undeclared_var_use
                                       : diag::err_omp_expected_var_arg)
          << Id.getName();
      return ExprError();
    }
  } else if (!(VD = Lookup.getAsSingle<VarDecl>())) {
    Diag(Id.getLoc(), diag::err_omp_expected_var_arg) << Id.getName();
    Diag(Lookup.getFoundDecl()->getLocation(), diag::note_declared_at);
    return ExprError();
  }
  Lookup.suppressDiagnostics();
 
  // OpenMP [2.9.2, Syntax, C/C++]
  //   Variables must be file-scope, namespace-scope, or static block-scope.
  if (Kind == OMPD_threadprivate && !VD->hasGlobalStorage()) {
    Diag(Id.getLoc(), diag::err_omp_global_var_arg)
        << getOpenMPDirectiveName(Kind) << !VD->isStaticLocal();
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
 
  VarDecl *CanonicalVD = VD->getCanonicalDecl();
  NamedDecl *ND = CanonicalVD;
  // OpenMP [2.9.2, Restrictions, C/C++, p.2]
  //   A threadprivate directive for file-scope variables must appear outside
  //   any definition or declaration.
  if (CanonicalVD->getDeclContext()->isTranslationUnit() &&
      !getCurLexicalContext()->isTranslationUnit()) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(Kind) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.3]
  //   A threadprivate directive for static class member variables must appear
  //   in the class definition, in the same scope in which the member
  //   variables are declared.
  if (CanonicalVD->isStaticDataMember() &&
      !CanonicalVD->getDeclContext()->Equals(getCurLexicalContext())) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(Kind) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.4]
  //   A threadprivate directive for namespace-scope variables must appear
  //   outside any definition or declaration other than the namespace
  //   definition itself.
  if (CanonicalVD->getDeclContext()->isNamespace() &&
      (!getCurLexicalContext()->isFileContext() ||
       !getCurLexicalContext()->Encloses(CanonicalVD->getDeclContext()))) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(Kind) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.6]
  //   A threadprivate directive for static block-scope variables must appear
  //   in the scope of the variable and not in a nested scope.
  if (CanonicalVD->isLocalVarDecl() && CurScope &&
      !isDeclInScope(ND, getCurLexicalContext(), CurScope)) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(Kind) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
 
  // OpenMP [2.9.2, Restrictions, C/C++, p.2-6]
  //   A threadprivate directive must lexically precede all references to any
  //   of the variables in its list.
  if (Kind == OMPD_threadprivate && VD->isUsed() &&
      !DSAStack->isThreadPrivate(VD)) {
    Diag(Id.getLoc(), diag::err_omp_var_used)
        << getOpenMPDirectiveName(Kind) << VD;
    return ExprError();
  }
 
  QualType ExprType = VD->getType().getNonReferenceType();
  return DeclRefExpr::Create(Context, NestedNameSpecifierLoc(),
                             SourceLocation(), VD,
                             /*RefersToEnclosingVariableOrCapture=*/false,
                             Id.getLoc(), ExprType, VK_LValue);
}
 
Sema::DeclGroupPtrTy
Sema::ActOnOpenMPThreadprivateDirective(SourceLocation Loc,
                                        ArrayRef<Expr *> VarList) {
  if (OMPThreadPrivateDecl *D = CheckOMPThreadPrivateDecl(Loc, VarList)) {
    CurContext->addDecl(D);
    return DeclGroupPtrTy::make(DeclGroupRef(D));
  }
  return nullptr;
}
 
namespace {
class LocalVarRefChecker final
    : public ConstStmtVisitor<LocalVarRefChecker, bool> {
  Sema &SemaRef;
 
public:
  bool VisitDeclRefExpr(const DeclRefExpr *E) {
    if (const auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
      if (VD->hasLocalStorage()) {
        SemaRef.Diag(E->getBeginLoc(),
                     diag::err_omp_local_var_in_threadprivate_init)
            << E->getSourceRange();
        SemaRef.Diag(VD->getLocation(), diag::note_defined_here)
            << VD << VD->getSourceRange();
        return true;
      }
    }
    return false;
  }
  bool VisitStmt(const Stmt *S) {
    for (const Stmt *Child : S->children()) {
      if (Child && Visit(Child))
        return true;
    }
    return false;
  }
  explicit LocalVarRefChecker(Sema &SemaRef) : SemaRef(SemaRef) {}
};
} // namespace
 
OMPThreadPrivateDecl *
Sema::CheckOMPThreadPrivateDecl(SourceLocation Loc, ArrayRef<Expr *> VarList) {
  SmallVector<Expr *, 8> Vars;
  for (Expr *RefExpr : VarList) {
    auto *DE = cast<DeclRefExpr>(RefExpr);
    auto *VD = cast<VarDecl>(DE->getDecl());
    SourceLocation ILoc = DE->getExprLoc();
 
    // Mark variable as used.
    VD->setReferenced();
    VD->markUsed(Context);
 
    QualType QType = VD->getType();
    if (QType->isDependentType() || QType->isInstantiationDependentType()) {
      // It will be analyzed later.
      Vars.push_back(DE);
      continue;
    }
 
    // OpenMP [2.9.2, Restrictions, C/C++, p.10]
    //   A threadprivate variable must not have an incomplete type.
    if (RequireCompleteType(ILoc, VD->getType(),
                            diag::err_omp_threadprivate_incomplete_type)) {
      continue;
    }
 
    // OpenMP [2.9.2, Restrictions, C/C++, p.10]
    //   A threadprivate variable must not have a reference type.
    if (VD->getType()->isReferenceType()) {
      Diag(ILoc, diag::err_omp_ref_type_arg)
          << getOpenMPDirectiveName(OMPD_threadprivate) << VD->getType();
      bool IsDecl =
          VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
      Diag(VD->getLocation(),
           IsDecl ? diag::note_previous_decl : diag::note_defined_here)
          << VD;
      continue;
    }
 
    // Check if this is a TLS variable. If TLS is not being supported, produce
    // the corresponding diagnostic.
    if ((VD->getTLSKind() != VarDecl::TLS_None &&
         !(VD->hasAttr<OMPThreadPrivateDeclAttr>() &&
           getLangOpts().OpenMPUseTLS &&
           getASTContext().getTargetInfo().isTLSSupported())) ||
        (VD->getStorageClass() == SC_Register && VD->hasAttr<AsmLabelAttr>() &&
         !VD->isLocalVarDecl())) {
      Diag(ILoc, diag::err_omp_var_thread_local)
          << VD << ((VD->getTLSKind() != VarDecl::TLS_None) ? 0 : 1);
      bool IsDecl =
          VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
      Diag(VD->getLocation(),
           IsDecl ? diag::note_previous_decl : diag::note_defined_here)
          << VD;
      continue;
    }
 
    // Check if initial value of threadprivate variable reference variable with
    // local storage (it is not supported by runtime).
    if (const Expr *Init = VD->getAnyInitializer()) {
      LocalVarRefChecker Checker(*this);
      if (Checker.Visit(Init))
        continue;
    }
 
    Vars.push_back(RefExpr);
    DSAStack->addDSA(VD, DE, OMPC_threadprivate);
    VD->addAttr(OMPThreadPrivateDeclAttr::CreateImplicit(
        Context, SourceRange(Loc, Loc)));
    if (ASTMutationListener *ML = Context.getASTMutationListener())
      ML->DeclarationMarkedOpenMPThreadPrivate(VD);
  }
  OMPThreadPrivateDecl *D = nullptr;
  if (!Vars.empty()) {
    D = OMPThreadPrivateDecl::Create(Context, getCurLexicalContext(), Loc,
                                     Vars);
    D->setAccess(AS_public);
  }
  return D;
}
 
static OMPAllocateDeclAttr::AllocatorTypeTy
getAllocatorKind(Sema &S, DSAStackTy *Stack, Expr *Allocator) {
  if (!Allocator)
    return OMPAllocateDeclAttr::OMPNullMemAlloc;
  if (Allocator->isTypeDependent() || Allocator->isValueDependent() ||
      Allocator->isInstantiationDependent() ||
      Allocator->containsUnexpandedParameterPack())
    return OMPAllocateDeclAttr::OMPUserDefinedMemAlloc;
  auto AllocatorKindRes = OMPAllocateDeclAttr::OMPUserDefinedMemAlloc;
  const Expr *AE = Allocator->IgnoreParenImpCasts();
  for (int I = 0; I < OMPAllocateDeclAttr::OMPUserDefinedMemAlloc; ++I) {
    auto AllocatorKind = static_cast<OMPAllocateDeclAttr::AllocatorTypeTy>(I);
    const Expr *DefAllocator = Stack->getAllocator(AllocatorKind);
    llvm::FoldingSetNodeID AEId, DAEId;
    AE->Profile(AEId, S.getASTContext(), /*Canonical=*/true);
    DefAllocator->Profile(DAEId, S.getASTContext(), /*Canonical=*/true);
    if (AEId == DAEId) {
      AllocatorKindRes = AllocatorKind;
      break;
    }
  }
  return AllocatorKindRes;
}
 
static bool checkPreviousOMPAllocateAttribute(
    Sema &S, DSAStackTy *Stack, Expr *RefExpr, VarDecl *VD,
    OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind, Expr *Allocator) {
  if (!VD->hasAttr<OMPAllocateDeclAttr>())
    return false;
  const auto *A = VD->getAttr<OMPAllocateDeclAttr>();
  Expr *PrevAllocator = A->getAllocator();
  OMPAllocateDeclAttr::AllocatorTypeTy PrevAllocatorKind =
      getAllocatorKind(S, Stack, PrevAllocator);
  bool AllocatorsMatch = AllocatorKind == PrevAllocatorKind;
  if (AllocatorsMatch &&
      AllocatorKind == OMPAllocateDeclAttr::OMPUserDefinedMemAlloc &&
      Allocator && PrevAllocator) {
    const Expr *AE = Allocator->IgnoreParenImpCasts();
    const Expr *PAE = PrevAllocator->IgnoreParenImpCasts();
    llvm::FoldingSetNodeID AEId, PAEId;
    AE->Profile(AEId, S.Context, /*Canonical=*/true);
    PAE->Profile(PAEId, S.Context, /*Canonical=*/true);
    AllocatorsMatch = AEId == PAEId;
  }
  if (!AllocatorsMatch) {
    SmallString<256> AllocatorBuffer;
    llvm::raw_svector_ostream AllocatorStream(AllocatorBuffer);
    if (Allocator)
      Allocator->printPretty(AllocatorStream, nullptr, S.getPrintingPolicy());
    SmallString<256> PrevAllocatorBuffer;
    llvm::raw_svector_ostream PrevAllocatorStream(PrevAllocatorBuffer);
    if (PrevAllocator)
      PrevAllocator->printPretty(PrevAllocatorStream, nullptr,
                                 S.getPrintingPolicy());
 
    SourceLocation AllocatorLoc =
        Allocator ? Allocator->getExprLoc() : RefExpr->getExprLoc();
    SourceRange AllocatorRange =
        Allocator ? Allocator->getSourceRange() : RefExpr->getSourceRange();
    SourceLocation PrevAllocatorLoc =
        PrevAllocator ? PrevAllocator->getExprLoc() : A->getLocation();
    SourceRange PrevAllocatorRange =
        PrevAllocator ? PrevAllocator->getSourceRange() : A->getRange();
    S.Diag(AllocatorLoc, diag::warn_omp_used_different_allocator)
        << (Allocator ? 1 : 0) << AllocatorStream.str()
        << (PrevAllocator ? 1 : 0) << PrevAllocatorStream.str()
        << AllocatorRange;
    S.Diag(PrevAllocatorLoc, diag::note_omp_previous_allocator)
        << PrevAllocatorRange;
    return true;
  }
  return false;
}
 
static void
applyOMPAllocateAttribute(Sema &S, VarDecl *VD,
                          OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind,
                          Expr *Allocator, Expr *Alignment, SourceRange SR) {
  if (VD->hasAttr<OMPAllocateDeclAttr>())
    return;
  if (Alignment &&
      (Alignment->isTypeDependent() || Alignment->isValueDependent() ||
       Alignment->isInstantiationDependent() ||
       Alignment->containsUnexpandedParameterPack()))
    // Apply later when we have a usable value.
    return;
  if (Allocator &&
      (Allocator->isTypeDependent() || Allocator->isValueDependent() ||
       Allocator->isInstantiationDependent() ||
       Allocator->containsUnexpandedParameterPack()))
    return;
  auto *A = OMPAllocateDeclAttr::CreateImplicit(S.Context, AllocatorKind,
                                                Allocator, Alignment, SR);
  VD->addAttr(A);
  if (ASTMutationListener *ML = S.Context.getASTMutationListener())
    ML->DeclarationMarkedOpenMPAllocate(VD, A);
}
 
Sema::DeclGroupPtrTy
Sema::ActOnOpenMPAllocateDirective(SourceLocation Loc, ArrayRef<Expr *> VarList,
                                   ArrayRef<OMPClause *> Clauses,
                                   DeclContext *Owner) {
  assert(Clauses.size() <= 2 && "Expected at most two clauses.");
  Expr *Alignment = nullptr;
  Expr *Allocator = nullptr;
  if (Clauses.empty()) {
    // OpenMP 5.0, 2.11.3 allocate Directive, Restrictions.
    // allocate directives that appear in a target region must specify an
    // allocator clause unless a requires directive with the dynamic_allocators
    // clause is present in the same compilation unit.
    if (LangOpts.OpenMPIsDevice &&
        !DSAStack->hasRequiresDeclWithClause<OMPDynamicAllocatorsClause>())
      targetDiag(Loc, diag::err_expected_allocator_clause);
  } else {
    for (const OMPClause *C : Clauses)
      if (const auto *AC = dyn_cast<OMPAllocatorClause>(C))
        Allocator = AC->getAllocator();
      else if (const auto *AC = dyn_cast<OMPAlignClause>(C))
        Alignment = AC->getAlignment();
      else
        llvm_unreachable("Unexpected clause on allocate directive");
  }
  OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind =
      getAllocatorKind(*this, DSAStack, Allocator);
  SmallVector<Expr *, 8> Vars;
  for (Expr *RefExpr : VarList) {
    auto *DE = cast<DeclRefExpr>(RefExpr);
    auto *VD = cast<VarDecl>(DE->getDecl());
 
    // Check if this is a TLS variable or global register.
    if (VD->getTLSKind() != VarDecl::TLS_None ||
        VD->hasAttr<OMPThreadPrivateDeclAttr>() ||
        (VD->getStorageClass() == SC_Register && VD->hasAttr<AsmLabelAttr>() &&
         !VD->isLocalVarDecl()))
      continue;
 
    // If the used several times in the allocate directive, the same allocator
    // must be used.
    if (checkPreviousOMPAllocateAttribute(*this, DSAStack, RefExpr, VD,
                                          AllocatorKind, Allocator))
      continue;
 
    // OpenMP, 2.11.3 allocate Directive, Restrictions, C / C++
    // If a list item has a static storage type, the allocator expression in the
    // allocator clause must be a constant expression that evaluates to one of
    // the predefined memory allocator values.
    if (Allocator && VD->hasGlobalStorage()) {
      if (AllocatorKind == OMPAllocateDeclAttr::OMPUserDefinedMemAlloc) {
        Diag(Allocator->getExprLoc(),
             diag::err_omp_expected_predefined_allocator)
            << Allocator->getSourceRange();
        bool IsDecl = VD->isThisDeclarationADefinition(Context) ==
                      VarDecl::DeclarationOnly;
        Diag(VD->getLocation(),
             IsDecl ? diag::note_previous_decl : diag::note_defined_here)
            << VD;
        continue;
      }
    }
 
    Vars.push_back(RefExpr);
    applyOMPAllocateAttribute(*this, VD, AllocatorKind, Allocator, Alignment,
                              DE->getSourceRange());
  }
  if (Vars.empty())
    return nullptr;
  if (!Owner)
    Owner = getCurLexicalContext();
  auto *D = OMPAllocateDecl::Create(Context, Owner, Loc, Vars, Clauses);
  D->setAccess(AS_public);
  Owner->addDecl(D);
  return DeclGroupPtrTy::make(DeclGroupRef(D));
}
 
Sema::DeclGroupPtrTy
Sema::ActOnOpenMPRequiresDirective(SourceLocation Loc,
                                   ArrayRef<OMPClause *> ClauseList) {
  OMPRequiresDecl *D = nullptr;
  if (!CurContext->isFileContext()) {
    Diag(Loc, diag::err_omp_invalid_scope) << "requires";
  } else {
    D = CheckOMPRequiresDecl(Loc, ClauseList);
    if (D) {
      CurContext->addDecl(D);
      DSAStack->addRequiresDecl(D);
    }
  }
  return DeclGroupPtrTy::make(DeclGroupRef(D));
}
 
void Sema::ActOnOpenMPAssumesDirective(SourceLocation Loc,
                                       OpenMPDirectiveKind DKind,
                                       ArrayRef<std::string> Assumptions,
                                       bool SkippedClauses) {
  if (!SkippedClauses && Assumptions.empty())
    Diag(Loc, diag::err_omp_no_clause_for_directive)
        << llvm::omp::getAllAssumeClauseOptions()
        << llvm::omp::getOpenMPDirectiveName(DKind);
 
  auto *AA = AssumptionAttr::Create(Context, llvm::join(Assumptions, ","), Loc);
  if (DKind == llvm::omp::Directive::OMPD_begin_assumes) {
    OMPAssumeScoped.push_back(AA);
    return;
  }
 
  // Global assumes without assumption clauses are ignored.
  if (Assumptions.empty())
    return;
 
  assert(DKind == llvm::omp::Directive::OMPD_assumes &&
         "Unexpected omp assumption directive!");
  OMPAssumeGlobal.push_back(AA);
 
  // The OMPAssumeGlobal scope above will take care of new declarations but
  // we also want to apply the assumption to existing ones, e.g., to
  // declarations in included headers. To this end, we traverse all existing
  // declaration contexts and annotate function declarations here.
  SmallVector<DeclContext *, 8> DeclContexts;
  auto *Ctx = CurContext;
  while (Ctx->getLexicalParent())
    Ctx = Ctx->getLexicalParent();
  DeclContexts.push_back(Ctx);
  while (!DeclContexts.empty()) {
    DeclContext *DC = DeclContexts.pop_back_val();
    for (auto *SubDC : DC->decls()) {
      if (SubDC->isInvalidDecl())
        continue;
      if (auto *CTD = dyn_cast<ClassTemplateDecl>(SubDC)) {
        DeclContexts.push_back(CTD->getTemplatedDecl());
        llvm::append_range(DeclContexts, CTD->specializations());
        continue;
      }
      if (auto *DC = dyn_cast<DeclContext>(SubDC))
        DeclContexts.push_back(DC);
      if (auto *F = dyn_cast<FunctionDecl>(SubDC)) {
        F->addAttr(AA);
        continue;
      }
    }
  }
}
 
void Sema::ActOnOpenMPEndAssumesDirective() {
  assert(isInOpenMPAssumeScope() && "Not in OpenMP assumes scope!");
  OMPAssumeScoped.pop_back();
}
 
OMPRequiresDecl *Sema::CheckOMPRequiresDecl(SourceLocation Loc,
                                            ArrayRef<OMPClause *> ClauseList) {
  /// For target specific clauses, the requires directive cannot be
  /// specified after the handling of any of the target regions in the
  /// current compilation unit.
  ArrayRef<SourceLocation> TargetLocations =
      DSAStack->getEncounteredTargetLocs();
  SourceLocation AtomicLoc = DSAStack->getAtomicDirectiveLoc();
  if (!TargetLocations.empty() || !AtomicLoc.isInvalid()) {
    for (const OMPClause *CNew : ClauseList) {
      // Check if any of the requires clauses affect target regions.
      if (isa<OMPUnifiedSharedMemoryClause>(CNew) ||
          isa<OMPUnifiedAddressClause>(CNew) ||
          isa<OMPReverseOffloadClause>(CNew) ||
          isa<OMPDynamicAllocatorsClause>(CNew)) {
        Diag(Loc, diag::err_omp_directive_before_requires)
            << "target" << getOpenMPClauseName(CNew->getClauseKind());
        for (SourceLocation TargetLoc : TargetLocations) {
          Diag(TargetLoc, diag::note_omp_requires_encountered_directive)
              << "target";
        }
      } else if (!AtomicLoc.isInvalid() &&
                 isa<OMPAtomicDefaultMemOrderClause>(CNew)) {
        Diag(Loc, diag::err_omp_directive_before_requires)
            << "atomic" << getOpenMPClauseName(CNew->getClauseKind());
        Diag(AtomicLoc, diag::note_omp_requires_encountered_directive)
            << "atomic";
      }
    }
  }
 
  if (!DSAStack->hasDuplicateRequiresClause(ClauseList))
    return OMPRequiresDecl::Create(Context, getCurLexicalContext(), Loc,
                                   ClauseList);
  return nullptr;
}
 
static void reportOriginalDsa(Sema &SemaRef, const DSAStackTy *Stack,
                              const ValueDecl *D,
                              const DSAStackTy::DSAVarData &DVar,
                              bool IsLoopIterVar) {
  if (DVar.RefExpr) {
    SemaRef.Diag(DVar.RefExpr->getExprLoc(), diag::note_omp_explicit_dsa)
        << getOpenMPClauseName(DVar.CKind);
    return;
  }
  enum {
    PDSA_StaticMemberShared,
    PDSA_StaticLocalVarShared,
    PDSA_LoopIterVarPrivate,
    PDSA_LoopIterVarLinear,
    PDSA_LoopIterVarLastprivate,
    PDSA_ConstVarShared,
    PDSA_GlobalVarShared,
    PDSA_TaskVarFirstprivate,
    PDSA_LocalVarPrivate,
    PDSA_Implicit
  } Reason = PDSA_Implicit;
  bool ReportHint = false;
  auto ReportLoc = D->getLocation();
  auto *VD = dyn_cast<VarDecl>(D);
  if (IsLoopIterVar) {
    if (DVar.CKind == OMPC_private)
      Reason = PDSA_LoopIterVarPrivate;
    else if (DVar.CKind == OMPC_lastprivate)
      Reason = PDSA_LoopIterVarLastprivate;
    else
      Reason = PDSA_LoopIterVarLinear;
  } else if (isOpenMPTaskingDirective(DVar.DKind) &&
             DVar.CKind == OMPC_firstprivate) {
    Reason = PDSA_TaskVarFirstprivate;
    ReportLoc = DVar.ImplicitDSALoc;
  } else if (VD && VD->isStaticLocal())
    Reason = PDSA_StaticLocalVarShared;
  else if (VD && VD->isStaticDataMember())
    Reason = PDSA_StaticMemberShared;
  else if (VD && VD->isFileVarDecl())
    Reason = PDSA_GlobalVarShared;
  else if (D->getType().isConstant(SemaRef.getASTContext()))
    Reason = PDSA_ConstVarShared;
  else if (VD && VD->isLocalVarDecl() && DVar.CKind == OMPC_private) {
    ReportHint = true;
    Reason = PDSA_LocalVarPrivate;
  }
  if (Reason != PDSA_Implicit) {
    SemaRef.Diag(ReportLoc, diag::note_omp_predetermined_dsa)
        << Reason << ReportHint
        << getOpenMPDirectiveName(Stack->getCurrentDirective());
  } else if (DVar.ImplicitDSALoc.isValid()) {
    SemaRef.Diag(DVar.ImplicitDSALoc, diag::note_omp_implicit_dsa)
        << getOpenMPClauseName(DVar.CKind);
  }
}
 
static OpenMPMapClauseKind
getMapClauseKindFromModifier(OpenMPDefaultmapClauseModifier M,
                             bool IsAggregateOrDeclareTarget) {
  OpenMPMapClauseKind Kind = OMPC_MAP_unknown;
  switch (M) {
  case OMPC_DEFAULTMAP_MODIFIER_alloc:
    Kind = OMPC_MAP_alloc;
    break;
  case OMPC_DEFAULTMAP_MODIFIER_to:
    Kind = OMPC_MAP_to;
    break;
  case OMPC_DEFAULTMAP_MODIFIER_from:
    Kind = OMPC_MAP_from;
    break;
  case OMPC_DEFAULTMAP_MODIFIER_tofrom:
    Kind = OMPC_MAP_tofrom;
    break;
  case OMPC_DEFAULTMAP_MODIFIER_present:
    // OpenMP 5.1 [2.21.7.3] defaultmap clause, Description]
    // If implicit-behavior is present, each variable referenced in the
    // construct in the category specified by variable-category is treated as if
    // it had been listed in a map clause with the map-type of alloc and
    // map-type-modifier of present.
    Kind = OMPC_MAP_alloc;
    break;
  case OMPC_DEFAULTMAP_MODIFIER_firstprivate:
  case OMPC_DEFAULTMAP_MODIFIER_last:
    llvm_unreachable("Unexpected defaultmap implicit behavior");
  case OMPC_DEFAULTMAP_MODIFIER_none:
  case OMPC_DEFAULTMAP_MODIFIER_default:
  case OMPC_DEFAULTMAP_MODIFIER_unknown:
    // IsAggregateOrDeclareTarget could be true if:
    // 1. the implicit behavior for aggregate is tofrom
    // 2. it's a declare target link
    if (IsAggregateOrDeclareTarget) {
      Kind = OMPC_MAP_tofrom;
      break;
    }
    llvm_unreachable("Unexpected defaultmap implicit behavior");
  }
  assert(Kind != OMPC_MAP_unknown && "Expect map kind to be known");
  return Kind;
}
 
namespace {
class DSAAttrChecker final : public StmtVisitor<DSAAttrChecker, void> {
  DSAStackTy *Stack;
  Sema &SemaRef;
  bool ErrorFound = false;
  bool TryCaptureCXXThisMembers = false;
  CapturedStmt *CS = nullptr;
  const static unsigned DefaultmapKindNum = OMPC_DEFAULTMAP_pointer + 1;
  llvm::SmallVector<Expr *, 4> ImplicitFirstprivate;
  llvm::SmallVector<Expr *, 4> ImplicitPrivate;
  llvm::SmallVector<Expr *, 4> ImplicitMap[DefaultmapKindNum][OMPC_MAP_delete];
  llvm::SmallVector<OpenMPMapModifierKind, NumberOfOMPMapClauseModifiers>
      ImplicitMapModifier[DefaultmapKindNum];
  Sema::VarsWithInheritedDSAType VarsWithInheritedDSA;
  llvm::SmallDenseSet<const ValueDecl *, 4> ImplicitDeclarations;
 
  void VisitSubCaptures(OMPExecutableDirective *S) {
    // Check implicitly captured variables.
    if (!S->hasAssociatedStmt() || !S->getAssociatedStmt())
      return;
    if (S->getDirectiveKind() == OMPD_atomic ||
        S->getDirectiveKind() == OMPD_critical ||
        S->getDirectiveKind() == OMPD_section ||
        S->getDirectiveKind() == OMPD_master ||
        S->getDirectiveKind() == OMPD_masked ||
        isOpenMPLoopTransformationDirective(S->getDirectiveKind())) {
      Visit(S->getAssociatedStmt());
      return;
    }
    visitSubCaptures(S->getInnermostCapturedStmt());
    // Try to capture inner this->member references to generate correct mappings
    // and diagnostics.
    if (TryCaptureCXXThisMembers ||
        (isOpenMPTargetExecutionDirective(Stack->getCurrentDirective()) &&
         llvm::any_of(S->getInnermostCapturedStmt()->captures(),
                      [](const CapturedStmt::Capture &C) {
                        return C.capturesThis();
                      }))) {
      bool SavedTryCaptureCXXThisMembers = TryCaptureCXXThisMembers;
      TryCaptureCXXThisMembers = true;
      Visit(S->getInnermostCapturedStmt()->getCapturedStmt());
      TryCaptureCXXThisMembers = SavedTryCaptureCXXThisMembers;
    }
    // In tasks firstprivates are not captured anymore, need to analyze them
    // explicitly.
    if (isOpenMPTaskingDirective(S->getDirectiveKind()) &&
        !isOpenMPTaskLoopDirective(S->getDirectiveKind())) {
      for (OMPClause *C : S->clauses())
        if (auto *FC = dyn_cast<OMPFirstprivateClause>(C)) {
          for (Expr *Ref : FC->varlists())
            Visit(Ref);
        }
    }
  }
 
public:
  void VisitDeclRefExpr(DeclRefExpr *E) {
    if (TryCaptureCXXThisMembers || E->isTypeDependent() ||
        E->isValueDependent() || E->containsUnexpandedParameterPack() ||
        E->isInstantiationDependent())
      return;
    if (auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
      // Check the datasharing rules for the expressions in the clauses.
      if (!CS || (isa<OMPCapturedExprDecl>(VD) && !CS->capturesVariable(VD) &&
                  !Stack->getTopDSA(VD, /*FromParent=*/false).RefExpr &&
                  !Stack->isImplicitDefaultFirstprivateFD(VD))) {
        if (auto *CED = dyn_cast<OMPCapturedExprDecl>(VD))
          if (!CED->hasAttr<OMPCaptureNoInitAttr>()) {
            Visit(CED->getInit());
            return;
          }
      } else if (VD->isImplicit() || isa<OMPCapturedExprDecl>(VD))
        // Do not analyze internal variables and do not enclose them into
        // implicit clauses.
        if (!Stack->isImplicitDefaultFirstprivateFD(VD))
          return;
      VD = VD->getCanonicalDecl();
      // Skip internally declared variables.
      if (VD->hasLocalStorage() && CS && !CS->capturesVariable(VD) &&
          !Stack->isImplicitDefaultFirstprivateFD(VD) &&
          !Stack->isImplicitTaskFirstprivate(VD))
        return;
      // Skip allocators in uses_allocators clauses.
      if (Stack->isUsesAllocatorsDecl(VD))
        return;
 
      DSAStackTy::DSAVarData DVar = Stack->getTopDSA(VD, /*FromParent=*/false);
      // Check if the variable has explicit DSA set and stop analysis if it so.
      if (DVar.RefExpr || !ImplicitDeclarations.insert(VD).second)
        return;
 
      // Skip internally declared static variables.
      llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
          OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD);
      if (VD->hasGlobalStorage() && CS && !CS->capturesVariable(VD) &&
          (Stack->hasRequiresDeclWithClause<OMPUnifiedSharedMemoryClause>() ||
           !Res || *Res != OMPDeclareTargetDeclAttr::MT_Link) &&
          !Stack->isImplicitDefaultFirstprivateFD(VD) &&
          !Stack->isImplicitTaskFirstprivate(VD))
        return;
 
      SourceLocation ELoc = E->getExprLoc();
      OpenMPDirectiveKind DKind = Stack->getCurrentDirective();
      // The default(none) clause requires that each variable that is referenced
      // in the construct, and does not have a predetermined data-sharing
      // attribute, must have its data-sharing attribute explicitly determined
      // by being listed in a data-sharing attribute clause.
      if (DVar.CKind == OMPC_unknown &&
          (Stack->getDefaultDSA() == DSA_none ||
           Stack->getDefaultDSA() == DSA_private ||
           Stack->getDefaultDSA() == DSA_firstprivate) &&
          isImplicitOrExplicitTaskingRegion(DKind) &&
          VarsWithInheritedDSA.count(VD) == 0) {
        bool InheritedDSA = Stack->getDefaultDSA() == DSA_none;
        if (!InheritedDSA && (Stack->getDefaultDSA() == DSA_firstprivate ||
                              Stack->getDefaultDSA() == DSA_private)) {
          DSAStackTy::DSAVarData DVar =
              Stack->getImplicitDSA(VD, /*FromParent=*/false);
          InheritedDSA = DVar.CKind == OMPC_unknown;
        }
        if (InheritedDSA)
          VarsWithInheritedDSA[VD] = E;
        if (Stack->getDefaultDSA() == DSA_none)
          return;
      }
 
      // OpenMP 5.0 [2.19.7.2, defaultmap clause, Description]
      // If implicit-behavior is none, each variable referenced in the
      // construct that does not have a predetermined data-sharing attribute
      // and does not appear in a to or link clause on a declare target
      // directive must be listed in a data-mapping attribute clause, a
      // data-sharing attribute clause (including a data-sharing attribute
      // clause on a combined construct where target. is one of the
      // constituent constructs), or an is_device_ptr clause.
      OpenMPDefaultmapClauseKind ClauseKind =
          getVariableCategoryFromDecl(SemaRef.getLangOpts(), VD);
      if (SemaRef.getLangOpts().OpenMP >= 50) {
        bool IsModifierNone = Stack->getDefaultmapModifier(ClauseKind) ==
                              OMPC_DEFAULTMAP_MODIFIER_none;
        if (DVar.CKind == OMPC_unknown && IsModifierNone &&
            VarsWithInheritedDSA.count(VD) == 0 && !Res) {
          // Only check for data-mapping attribute and is_device_ptr here
          // since we have already make sure that the declaration does not
          // have a data-sharing attribute above
          if (!Stack->checkMappableExprComponentListsForDecl(
                  VD, /*CurrentRegionOnly=*/true,
                  [VD](OMPClauseMappableExprCommon::MappableExprComponentListRef
                           MapExprComponents,
                       OpenMPClauseKind) {
                    auto MI = MapExprComponents.rbegin();
                    auto ME = MapExprComponents.rend();
                    return MI != ME && MI->getAssociatedDeclaration() == VD;
                  })) {
            VarsWithInheritedDSA[VD] = E;
            return;
          }
        }
      }
      if (SemaRef.getLangOpts().OpenMP > 50) {
        bool IsModifierPresent = Stack->getDefaultmapModifier(ClauseKind) ==
                                 OMPC_DEFAULTMAP_MODIFIER_present;
        if (IsModifierPresent) {
          if (!llvm::is_contained(ImplicitMapModifier[ClauseKind],
                                  OMPC_MAP_MODIFIER_present)) {
            ImplicitMapModifier[ClauseKind].push_back(
                OMPC_MAP_MODIFIER_present);
          }
        }
      }
 
      if (isOpenMPTargetExecutionDirective(DKind) &&
          !Stack->isLoopControlVariable(VD).first) {
        if (!Stack->checkMappableExprComponentListsForDecl(
                VD, /*CurrentRegionOnly=*/true,
                [this](OMPClauseMappableExprCommon::MappableExprComponentListRef
                           StackComponents,
                       OpenMPClauseKind) {
                  if (SemaRef.LangOpts.OpenMP >= 50)
                    return !StackComponents.empty();
                  // Variable is used if it has been marked as an array, array
                  // section, array shaping or the variable iself.
                  return StackComponents.size() == 1 ||
                         llvm::all_of(
                             llvm::drop_begin(llvm::reverse(StackComponents)),
                             [](const OMPClauseMappableExprCommon::
                                    MappableComponent &MC) {
                               return MC.getAssociatedDeclaration() ==
                                          nullptr &&
                                      (isa<OMPArraySectionExpr>(
                                           MC.getAssociatedExpression()) ||
                                       isa<OMPArrayShapingExpr>(
                                           MC.getAssociatedExpression()) ||
                                       isa<ArraySubscriptExpr>(
                                           MC.getAssociatedExpression()));
                             });
                })) {
          bool IsFirstprivate = false;
          // By default lambdas are captured as firstprivates.
          if (const auto *RD =
                  VD->getType().getNonReferenceType()->getAsCXXRecordDecl())
            IsFirstprivate = RD->isLambda();
          IsFirstprivate =
              IsFirstprivate || (Stack->mustBeFirstprivate(ClauseKind) && !Res);
          if (IsFirstprivate) {
            ImplicitFirstprivate.emplace_back(E);
          } else {
            OpenMPDefaultmapClauseModifier M =
                Stack->getDefaultmapModifier(ClauseKind);
            OpenMPMapClauseKind Kind = getMapClauseKindFromModifier(
                M, ClauseKind == OMPC_DEFAULTMAP_aggregate || Res);
            ImplicitMap[ClauseKind][Kind].emplace_back(E);
          }
          return;
        }
      }
 
      // OpenMP [2.9.3.6, Restrictions, p.2]
      //  A list item that appears in a reduction clause of the innermost
      //  enclosing worksharing or parallel construct may not be accessed in an
      //  explicit task.
      DVar = Stack->hasInnermostDSA(
          VD,
          [](OpenMPClauseKind C, bool AppliedToPointee) {
            return C == OMPC_reduction && !AppliedToPointee;
          },
          [](OpenMPDirectiveKind K) {
            return isOpenMPParallelDirective(K) ||
                   isOpenMPWorksharingDirective(K) || isOpenMPTeamsDirective(K);
          },
          /*FromParent=*/true);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind == OMPC_reduction) {
        ErrorFound = true;
        SemaRef.Diag(ELoc, diag::err_omp_reduction_in_task);
        reportOriginalDsa(SemaRef, Stack, VD, DVar);
        return;
      }
 
      // Define implicit data-sharing attributes for task.
      DVar = Stack->getImplicitDSA(VD, /*FromParent=*/false);
      if (((isOpenMPTaskingDirective(DKind) && DVar.CKind != OMPC_shared) ||
           (((Stack->getDefaultDSA() == DSA_firstprivate &&
              DVar.CKind == OMPC_firstprivate) ||
             (Stack->getDefaultDSA() == DSA_private &&
              DVar.CKind == OMPC_private)) &&
            !DVar.RefExpr)) &&
          !Stack->isLoopControlVariable(VD).first) {
        if (Stack->getDefaultDSA() == DSA_private)
          ImplicitPrivate.push_back(E);
        else
          ImplicitFirstprivate.push_back(E);
        return;
      }
 
      // Store implicitly used globals with declare target link for parent
      // target.
      if (!isOpenMPTargetExecutionDirective(DKind) && Res &&
          *Res == OMPDeclareTargetDeclAttr::MT_Link) {
        Stack->addToParentTargetRegionLinkGlobals(E);
        return;
      }
    }
  }
  void VisitMemberExpr(MemberExpr *E) {
    if (E->isTypeDependent() || E->isValueDependent() ||
        E->containsUnexpandedParameterPack() || E->isInstantiationDependent())
      return;
    auto *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
    OpenMPDirectiveKind DKind = Stack->getCurrentDirective();
    if (auto *TE = dyn_cast<CXXThisExpr>(E->getBase()->IgnoreParenCasts())) {
      if (!FD)
        return;
      DSAStackTy::DSAVarData DVar = Stack->getTopDSA(FD, /*FromParent=*/false);
      // Check if the variable has explicit DSA set and stop analysis if it
      // so.
      if (DVar.RefExpr || !ImplicitDeclarations.insert(FD).second)
        return;
 
      if (isOpenMPTargetExecutionDirective(DKind) &&
          !Stack->isLoopControlVariable(FD).first &&
          !Stack->checkMappableExprComponentListsForDecl(
              FD, /*CurrentRegionOnly=*/true,
              [](OMPClauseMappableExprCommon::MappableExprComponentListRef
                     StackComponents,
                 OpenMPClauseKind) {
                return isa<CXXThisExpr>(
                    cast<MemberExpr>(
                        StackComponents.back().getAssociatedExpression())
                        ->getBase()
                        ->IgnoreParens());
              })) {
        // OpenMP 4.5 [2.15.5.1, map Clause, Restrictions, C/C++, p.3]
        //  A bit-field cannot appear in a map clause.
        //
        if (FD->isBitField())
          return;
 
        // Check to see if the member expression is referencing a class that
        // has already been explicitly mapped
        if (Stack->isClassPreviouslyMapped(TE->getType()))
          return;
 
        OpenMPDefaultmapClauseModifier Modifier =
            Stack->getDefaultmapModifier(OMPC_DEFAULTMAP_aggregate);
        OpenMPDefaultmapClauseKind ClauseKind =
            getVariableCategoryFromDecl(SemaRef.getLangOpts(), FD);
        OpenMPMapClauseKind Kind = getMapClauseKindFromModifier(
            Modifier, /*IsAggregateOrDeclareTarget*/ true);
        ImplicitMap[ClauseKind][Kind].emplace_back(E);
        return;
      }
 
      SourceLocation ELoc = E->getExprLoc();
      // OpenMP [2.9.3.6, Restrictions, p.2]
      //  A list item that appears in a reduction clause of the innermost
      //  enclosing worksharing or parallel construct may not be accessed in
      //  an  explicit task.
      DVar = Stack->hasInnermostDSA(
          FD,
          [](OpenMPClauseKind C, bool AppliedToPointee) {
            return C == OMPC_reduction && !AppliedToPointee;
          },
          [](OpenMPDirectiveKind K) {
            return isOpenMPParallelDirective(K) ||
                   isOpenMPWorksharingDirective(K) || isOpenMPTeamsDirective(K);
          },
          /*FromParent=*/true);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind == OMPC_reduction) {
        ErrorFound = true;
        SemaRef.Diag(ELoc, diag::err_omp_reduction_in_task);
        reportOriginalDsa(SemaRef, Stack, FD, DVar);
        return;
      }
 
      // Define implicit data-sharing attributes for task.
      DVar = Stack->getImplicitDSA(FD, /*FromParent=*/false);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind != OMPC_shared &&
          !Stack->isLoopControlVariable(FD).first) {
        // Check if there is a captured expression for the current field in the
        // region. Do not mark it as firstprivate unless there is no captured
        // expression.
        // TODO: try to make it firstprivate.
        if (DVar.CKind != OMPC_unknown)
          ImplicitFirstprivate.push_back(E);
      }
      return;
    }
    if (isOpenMPTargetExecutionDirective(DKind)) {
      OMPClauseMappableExprCommon::MappableExprComponentList CurComponents;
      if (!checkMapClauseExpressionBase(SemaRef, E, CurComponents, OMPC_map,
                                        Stack->getCurrentDirective(),
                                        /*NoDiagnose=*/true))
        return;
      const auto *VD = cast<ValueDecl>(
          CurComponents.back().getAssociatedDeclaration()->getCanonicalDecl());
      if (!Stack->checkMappableExprComponentListsForDecl(
              VD, /*CurrentRegionOnly=*/true,
              [&CurComponents](
                  OMPClauseMappableExprCommon::MappableExprComponentListRef
                      StackComponents,
                  OpenMPClauseKind) {
                auto CCI = CurComponents.rbegin();
                auto CCE = CurComponents.rend();
                for (const auto &SC : llvm::reverse(StackComponents)) {
                  // Do both expressions have the same kind?
                  if (CCI->getAssociatedExpression()->getStmtClass() !=
                      SC.getAssociatedExpression()->getStmtClass())
                    if (!((isa<OMPArraySectionExpr>(
                               SC.getAssociatedExpression()) ||
                           isa<OMPArrayShapingExpr>(
                               SC.getAssociatedExpression())) &&
                          isa<ArraySubscriptExpr>(
                              CCI->getAssociatedExpression())))
                      return false;
 
                  const Decl *CCD = CCI->getAssociatedDeclaration();
                  const Decl *SCD = SC.getAssociatedDeclaration();
                  CCD = CCD ? CCD->getCanonicalDecl() : nullptr;
                  SCD = SCD ? SCD->getCanonicalDecl() : nullptr;
                  if (SCD != CCD)
                    return false;
                  std::advance(CCI, 1);
                  if (CCI == CCE)
                    break;
                }
                return true;
              })) {
        Visit(E->getBase());
      }
    } else if (!TryCaptureCXXThisMembers) {
      Visit(E->getBase());
    }
  }
  void VisitOMPExecutableDirective(OMPExecutableDirective *S) {
    for (OMPClause *C : S->clauses()) {
      // Skip analysis of arguments of private clauses for task|target
      // directives.
      if (isa_and_nonnull<OMPPrivateClause>(C))
        continue;
      // Skip analysis of arguments of implicitly defined firstprivate clause
      // for task|target directives.
      // Skip analysis of arguments of implicitly defined map clause for target
      // directives.
      if (C && !((isa<OMPFirstprivateClause>(C) || isa<OMPMapClause>(C)) &&
                 C->isImplicit() &&
                 !isOpenMPTaskingDirective(Stack->getCurrentDirective()))) {
        for (Stmt *CC : C->children()) {
          if (CC)
            Visit(CC);
        }
      }
    }
    // Check implicitly captured variables.
    VisitSubCaptures(S);
  }
 
  void VisitOMPLoopTransformationDirective(OMPLoopTransformationDirective *S) {
    // Loop transformation directives do not introduce data sharing
    VisitStmt(S);
  }
 
  void VisitCallExpr(CallExpr *S) {
    for (Stmt *C : S->arguments()) {
      if (C) {
        // Check implicitly captured variables in the task-based directives to
        // check if they must be firstprivatized.
        Visit(C);
      }
    }
    if (Expr *Callee = S->getCallee())
      if (auto *CE = dyn_cast<MemberExpr>(Callee->IgnoreParenImpCasts()))
        Visit(CE->getBase());
  }
  void VisitStmt(Stmt *S) {
    for (Stmt *C : S->children()) {
      if (C) {
        // Check implicitly captured variables in the task-based directives to
        // check if they must be firstprivatized.
        Visit(C);
      }
    }
  }
 
  void visitSubCaptures(CapturedStmt *S) {
    for (const CapturedStmt::Capture &Cap : S->captures()) {
      if (!Cap.capturesVariable() && !Cap.capturesVariableByCopy())
        continue;
      VarDecl *VD = Cap.getCapturedVar();
      // Do not try to map the variable if it or its sub-component was mapped
      // already.
      if (isOpenMPTargetExecutionDirective(Stack->getCurrentDirective()) &&
          Stack->checkMappableExprComponentListsForDecl(
              VD, /*CurrentRegionOnly=*/true,
              [](OMPClauseMappableExprCommon::MappableExprComponentListRef,
                 OpenMPClauseKind) { return true; }))
        continue;
      DeclRefExpr *DRE = buildDeclRefExpr(
          SemaRef, VD, VD->getType().getNonLValueExprType(SemaRef.Context),
          Cap.getLocation(), /*RefersToCapture=*/true);
      Visit(DRE);
    }
  }
  bool isErrorFound() const { return ErrorFound; }
  ArrayRef<Expr *> getImplicitFirstprivate() const {
    return ImplicitFirstprivate;
  }
  ArrayRef<Expr *> getImplicitPrivate() const { return ImplicitPrivate; }
  ArrayRef<Expr *> getImplicitMap(OpenMPDefaultmapClauseKind DK,
                                  OpenMPMapClauseKind MK) const {
    return ImplicitMap[DK][MK];
  }
  ArrayRef<OpenMPMapModifierKind>
  getImplicitMapModifier(OpenMPDefaultmapClauseKind Kind) const {
    return ImplicitMapModifier[Kind];
  }
  const Sema::VarsWithInheritedDSAType &getVarsWithInheritedDSA() const {
    return VarsWithInheritedDSA;
  }
 
  DSAAttrChecker(DSAStackTy *S, Sema &SemaRef, CapturedStmt *CS)
      : Stack(S), SemaRef(SemaRef), ErrorFound(false), CS(CS) {
    // Process declare target link variables for the target directives.
    if (isOpenMPTargetExecutionDirective(S->getCurrentDirective())) {
      for (DeclRefExpr *E : Stack->getLinkGlobals())
        Visit(E);
    }
  }
};
} // namespace
 
static void handleDeclareVariantConstructTrait(DSAStackTy *Stack,
                                               OpenMPDirectiveKind DKind,
                                               bool ScopeEntry) {
  SmallVector<llvm::omp::TraitProperty, 8> Traits;
  if (isOpenMPTargetExecutionDirective(DKind))
    Traits.emplace_back(llvm::omp::TraitProperty::construct_target_target);
  if (isOpenMPTeamsDirective(DKind))
    Traits.emplace_back(llvm::omp::TraitProperty::construct_teams_teams);
  if (isOpenMPParallelDirective(DKind))
    Traits.emplace_back(llvm::omp::TraitProperty::construct_parallel_parallel);
  if (isOpenMPWorksharingDirective(DKind))
    Traits.emplace_back(llvm::omp::TraitProperty::construct_for_for);
  if (isOpenMPSimdDirective(DKind))
    Traits.emplace_back(llvm::omp::TraitProperty::construct_simd_simd);
  Stack->handleConstructTrait(Traits, ScopeEntry);
}
 
void Sema::ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope) {
  switch (DKind) {
  case OMPD_parallel:
  case OMPD_parallel_for:
  case OMPD_parallel_for_simd:
  case OMPD_parallel_sections:
  case OMPD_parallel_master:
  case OMPD_parallel_masked:
  case OMPD_parallel_loop:
  case OMPD_teams:
  case OMPD_teams_distribute:
  case OMPD_teams_distribute_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_target_teams:
  case OMPD_target_parallel:
  case OMPD_target_parallel_for:
  case OMPD_target_parallel_for_simd:
  case OMPD_target_teams_loop:
  case OMPD_target_parallel_loop:
  case OMPD_target_teams_distribute:
  case OMPD_target_teams_distribute_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params, /*OpenMPCaptureLevel=*/0);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    Sema::CapturedParamNameType ParamsTarget[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTarget, /*OpenMPCaptureLevel=*/1);
    Sema::CapturedParamNameType ParamsTeamsOrParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeamsOrParallel, /*OpenMPCaptureLevel=*/2);
    break;
  }
  case OMPD_target:
  case OMPD_target_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params, /*OpenMPCaptureLevel=*/0);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             std::make_pair(StringRef(), QualType()),
                             /*OpenMPCaptureLevel=*/1);
    break;
  }
  case OMPD_atomic:
  case OMPD_critical:
  case OMPD_section:
  case OMPD_master:
  case OMPD_masked:
  case OMPD_tile:
  case OMPD_unroll:
    break;
  case OMPD_loop:
    // TODO: 'loop' may require additional parameters depending on the binding.
    // Treat similar to OMPD_simd/OMPD_for for now.
  case OMPD_simd:
  case OMPD_for:
  case OMPD_for_simd:
  case OMPD_sections:
  case OMPD_single:
  case OMPD_taskgroup:
  case OMPD_distribute:
  case OMPD_distribute_simd:
  case OMPD_ordered:
  case OMPD_target_data:
  case OMPD_dispatch: {
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_task: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_taskloop:
  case OMPD_taskloop_simd:
  case OMPD_master_taskloop:
  case OMPD_masked_taskloop:
  case OMPD_masked_taskloop_simd:
  case OMPD_master_taskloop_simd: {
    QualType KmpInt32Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/32, /*Signed=*/1)
            .withConst();
    QualType KmpUInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0)
            .withConst();
    QualType KmpInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1)
            .withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(".lb.", KmpUInt64Ty),
        std::make_pair(".ub.", KmpUInt64Ty),
        std::make_pair(".st.", KmpInt64Ty),
        std::make_pair(".liter.", KmpInt32Ty),
        std::make_pair(".reductions.", VoidPtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_parallel_masked_taskloop:
  case OMPD_parallel_masked_taskloop_simd:
  case OMPD_parallel_master_taskloop:
  case OMPD_parallel_master_taskloop_simd: {
    QualType KmpInt32Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/32, /*Signed=*/1)
            .withConst();
    QualType KmpUInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0)
            .withConst();
    QualType KmpInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1)
            .withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    Sema::CapturedParamNameType ParamsParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'parallel'.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsParallel, /*OpenMPCaptureLevel=*/0);
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(".lb.", KmpUInt64Ty),
        std::make_pair(".ub.", KmpUInt64Ty),
        std::make_pair(".st.", KmpInt64Ty),
        std::make_pair(".liter.", KmpInt32Ty),
        std::make_pair(".reductions.", VoidPtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params, /*OpenMPCaptureLevel=*/1);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_distribute_parallel_for_simd:
  case OMPD_distribute_parallel_for: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_target_teams_distribute_parallel_for:
  case OMPD_target_teams_distribute_parallel_for_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
 
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params, /*OpenMPCaptureLevel=*/0);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    Sema::CapturedParamNameType ParamsTarget[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTarget, /*OpenMPCaptureLevel=*/1);
 
    Sema::CapturedParamNameType ParamsTeams[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeams, /*OpenMPCaptureLevel=*/2);
 
    Sema::CapturedParamNameType ParamsParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsParallel, /*OpenMPCaptureLevel=*/3);
    break;
  }
 
  case OMPD_teams_loop: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
 
    Sema::CapturedParamNameType ParamsTeams[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams'.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeams, /*OpenMPCaptureLevel=*/0);
    break;
  }
 
  case OMPD_teams_distribute_parallel_for:
  case OMPD_teams_distribute_parallel_for_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
 
    Sema::CapturedParamNameType ParamsTeams[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeams, /*OpenMPCaptureLevel=*/0);
 
    Sema::CapturedParamNameType ParamsParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsParallel, /*OpenMPCaptureLevel=*/1);
    break;
  }
  case OMPD_target_update:
  case OMPD_target_enter_data:
  case OMPD_target_exit_data: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, {}, AttributeCommonInfo::AS_Keyword,
            AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_threadprivate:
  case OMPD_allocate:
  case OMPD_taskyield:
  case OMPD_error:
  case OMPD_barrier:
  case OMPD_taskwait:
  case OMPD_cancellation_point:
  case OMPD_cancel:
  case OMPD_flush:
  case OMPD_depobj:
  case OMPD_scan:
  case OMPD_declare_reduction:
  case OMPD_declare_mapper:
  case OMPD_declare_simd:
  case OMPD_declare_target:
  case OMPD_end_declare_target:
  case OMPD_requires:
  case OMPD_declare_variant:
  case OMPD_begin_declare_variant:
  case OMPD_end_declare_variant:
  case OMPD_metadirective:
    llvm_unreachable("OpenMP Directive is not allowed");
  case OMPD_unknown:
  default:
    llvm_unreachable("Unknown OpenMP directive");
  }
  DSAStack->setContext(CurContext);
  handleDeclareVariantConstructTrait(DSAStack, DKind, /* ScopeEntry */ true);
}
 
int Sema::getNumberOfConstructScopes(unsigned Level) const {
  return getOpenMPCaptureLevels(DSAStack->getDirective(Level));
}
 
int Sema::getOpenMPCaptureLevels(OpenMPDirectiveKind DKind) {
  SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
  getOpenMPCaptureRegions(CaptureRegions, DKind);
  return CaptureRegions.size();
}
 
static OMPCapturedExprDecl *buildCaptureDecl(Sema &S, IdentifierInfo *Id,
                                             Expr *CaptureExpr, bool WithInit,
                                             DeclContext *CurContext,
                                             bool AsExpression) {
  assert(CaptureExpr);
  ASTContext &C = S.getASTContext();
  Expr *Init = AsExpression ? CaptureExpr : CaptureExpr->IgnoreImpCasts();
  QualType Ty = Init->getType();
  if (CaptureExpr->getObjectKind() == OK_Ordinary && CaptureExpr->isGLValue()) {
    if (S.getLangOpts().CPlusPlus) {
      Ty = C.getLValueReferenceType(Ty);
    } else {
      Ty = C.getPointerType(Ty);
      ExprResult Res =
          S.CreateBuiltinUnaryOp(CaptureExpr->getExprLoc(), UO_AddrOf, Init);
      if (!Res.isUsable())
        return nullptr;
      Init = Res.get();
    }
    WithInit = true;
  }
  auto *CED = OMPCapturedExprDecl::Create(C, CurContext, Id, Ty,
                                          CaptureExpr->getBeginLoc());
  if (!WithInit)
    CED->addAttr(OMPCaptureNoInitAttr::CreateImplicit(C));
  CurContext->addHiddenDecl(CED);
  Sema::TentativeAnalysisScope Trap(S);
  S.AddInitializerToDecl(CED, Init, /*DirectInit=*/false);
  return CED;
}
 
static DeclRefExpr *buildCapture(Sema &S, ValueDecl *D, Expr *CaptureExpr,
                                 bool WithInit) {
  OMPCapturedExprDecl *CD;
  if (VarDecl *VD = S.isOpenMPCapturedDecl(D))
    CD = cast<OMPCapturedExprDecl>(VD);
  else
    CD = buildCaptureDecl(S, D->getIdentifier(), CaptureExpr, WithInit,
                          S.CurContext,
                          /*AsExpression=*/false);
  return buildDeclRefExpr(S, CD, CD->getType().getNonReferenceType(),
                          CaptureExpr->getExprLoc());
}
 
static ExprResult buildCapture(Sema &S, Expr *CaptureExpr, DeclRefExpr *&Ref) {
  CaptureExpr = S.DefaultLvalueConversion(CaptureExpr).get();
  if (!Ref) {
    OMPCapturedExprDecl *CD = buildCaptureDecl(
        S, &S.getASTContext().Idents.get(".capture_expr."), CaptureExpr,
        /*WithInit=*/true, S.CurContext, /*AsExpression=*/true);
    Ref = buildDeclRefExpr(S, CD, CD->getType().getNonReferenceType(),
                           CaptureExpr->getExprLoc());
  }
  ExprResult Res = Ref;
  if (!S.getLangOpts().CPlusPlus &&
      CaptureExpr->getObjectKind() == OK_Ordinary && CaptureExpr->isGLValue() &&
      Ref->getType()->isPointerType()) {
    Res = S.CreateBuiltinUnaryOp(CaptureExpr->getExprLoc(), UO_Deref, Ref);
    if (!Res.isUsable())
      return ExprError();
  }
  return S.DefaultLvalueConversion(Res.get());
}
 
namespace {
// OpenMP directives parsed in this section are represented as a
// CapturedStatement with an associated statement.  If a syntax error
// is detected during the parsing of the associated statement, the
// compiler must abort processing and close the CapturedStatement.
//
// Combined directives such as 'target parallel' have more than one
// nested CapturedStatements.  This RAII ensures that we unwind out
// of all the nested CapturedStatements when an error is found.
class CaptureRegionUnwinderRAII {
private:
  Sema &S;
  bool &ErrorFound;
  OpenMPDirectiveKind DKind = OMPD_unknown;
 
public:
  CaptureRegionUnwinderRAII(Sema &S, bool &ErrorFound,
                            OpenMPDirectiveKind DKind)
      : S(S), ErrorFound(ErrorFound), DKind(DKind) {}
  ~CaptureRegionUnwinderRAII() {
    if (ErrorFound) {
      int ThisCaptureLevel = S.getOpenMPCaptureLevels(DKind);
      while (--ThisCaptureLevel >= 0)
        S.ActOnCapturedRegionError();
    }
  }
};
} // namespace
 
void Sema::tryCaptureOpenMPLambdas(ValueDecl *V) {
  // Capture variables captured by reference in lambdas for target-based
  // directives.
  if (!CurContext->isDependentContext() &&
      (isOpenMPTargetExecutionDirective(DSAStack->getCurrentDirective()) ||
       isOpenMPTargetDataManagementDirective(
           DSAStack->getCurrentDirective()))) {
    QualType Type = V->getType();
    if (const auto *RD = Type.getCanonicalType()
                             .getNonReferenceType()
                             ->getAsCXXRecordDecl()) {
      bool SavedForceCaptureByReferenceInTargetExecutable =
          DSAStack->isForceCaptureByReferenceInTargetExecutable();
      DSAStack->setForceCaptureByReferenceInTargetExecutable(
          /*V=*/true);
      if (RD->isLambda()) {
        llvm::DenseMap<const ValueDecl *, FieldDecl *> Captures;
        FieldDecl *ThisCapture;
        RD->getCaptureFields(Captures, ThisCapture);
        for (const LambdaCapture &LC : RD->captures()) {
          if (LC.getCaptureKind() == LCK_ByRef) {
            VarDecl *VD = cast<VarDecl>(LC.getCapturedVar());
            DeclContext *VDC = VD->getDeclContext();
            if (!VDC->Encloses(CurContext))
              continue;
            MarkVariableReferenced(LC.getLocation(), VD);
          } else if (LC.getCaptureKind() == LCK_This) {
            QualType ThisTy = getCurrentThisType();
            if (!ThisTy.isNull() &&
                Context.typesAreCompatible(ThisTy, ThisCapture->getType()))
              CheckCXXThisCapture(LC.getLocation());
          }
        }
      }
      DSAStack->setForceCaptureByReferenceInTargetExecutable(
          SavedForceCaptureByReferenceInTargetExecutable);
    }
  }
}
 
static bool checkOrderedOrderSpecified(Sema &S,
                                       const ArrayRef<OMPClause *> Clauses) {
  const OMPOrderedClause *Ordered = nullptr;
  const OMPOrderClause *Order = nullptr;
 
  for (const OMPClause *Clause : Clauses) {
    if (Clause->getClauseKind() == OMPC_ordered)
      Ordered = cast<OMPOrderedClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_order) {
      Order = cast<OMPOrderClause>(Clause);
      if (Order->getKind() != OMPC_ORDER_concurrent)
        Order = nullptr;
    }
    if (Ordered && Order)
      break;
  }
 
  if (Ordered && Order) {
    S.Diag(Order->getKindKwLoc(),
           diag::err_omp_simple_clause_incompatible_with_ordered)
        << getOpenMPClauseName(OMPC_order)
        << getOpenMPSimpleClauseTypeName(OMPC_order, OMPC_ORDER_concurrent)
        << SourceRange(Order->getBeginLoc(), Order->getEndLoc());
    S.Diag(Ordered->getBeginLoc(), diag::note_omp_ordered_param)
        << 0 << SourceRange(Ordered->getBeginLoc(), Ordered->getEndLoc());
    return true;
  }
  return false;
}
 
StmtResult Sema::ActOnOpenMPRegionEnd(StmtResult S,
                                      ArrayRef<OMPClause *> Clauses) {
  handleDeclareVariantConstructTrait(DSAStack, DSAStack->getCurrentDirective(),
                                     /* ScopeEntry */ false);
  if (DSAStack->getCurrentDirective() == OMPD_atomic ||
      DSAStack->getCurrentDirective() == OMPD_critical ||
      DSAStack->getCurrentDirective() == OMPD_section ||
      DSAStack->getCurrentDirective() == OMPD_master ||
      DSAStack->getCurrentDirective() == OMPD_masked)
    return S;
 
  bool ErrorFound = false;
  CaptureRegionUnwinderRAII CaptureRegionUnwinder(
      *this, ErrorFound, DSAStack->getCurrentDirective());
  if (!S.isUsable()) {
    ErrorFound = true;
    return StmtError();
  }
 
  SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
  getOpenMPCaptureRegions(CaptureRegions, DSAStack->getCurrentDirective());
  OMPOrderedClause *OC = nullptr;
  OMPScheduleClause *SC = nullptr;
  SmallVector<const OMPLinearClause *, 4> LCs;
  SmallVector<const OMPClauseWithPreInit *, 4> PICs;
  // This is required for proper codegen.
  for (OMPClause *Clause : Clauses) {
    if (!LangOpts.OpenMPSimd &&
        (isOpenMPTaskingDirective(DSAStack->getCurrentDirective()) ||
         DSAStack->getCurrentDirective() == OMPD_target) &&
        Clause->getClauseKind() == OMPC_in_reduction) {
      // Capture taskgroup task_reduction descriptors inside the tasking regions
      // with the corresponding in_reduction items.
      auto *IRC = cast<OMPInReductionClause>(Clause);
      for (Expr *E : IRC->taskgroup_descriptors())
        if (E)
          MarkDeclarationsReferencedInExpr(E);
    }
    if (isOpenMPPrivate(Clause->getClauseKind()) ||
        Clause->getClauseKind() == OMPC_copyprivate ||
        (getLangOpts().OpenMPUseTLS &&
         getASTContext().getTargetInfo().isTLSSupported() &&
         Clause->getClauseKind() == OMPC_copyin)) {
      DSAStack->setForceVarCapturing(Clause->getClauseKind() == OMPC_copyin);
      // Mark all variables in private list clauses as used in inner region.
      for (Stmt *VarRef : Clause->children()) {
        if (auto *E = cast_or_null<Expr>(VarRef)) {
          MarkDeclarationsReferencedInExpr(E);
        }
      }
      DSAStack->setForceVarCapturing(/*V=*/false);
    } else if (isOpenMPLoopTransformationDirective(
                   DSAStack->getCurrentDirective())) {
      assert(CaptureRegions.empty() &&
             "No captured regions in loop transformation directives.");
    } else if (CaptureRegions.size() > 1 ||
               CaptureRegions.back() != OMPD_unknown) {
      if (auto *C = OMPClauseWithPreInit::get(Clause))
        PICs.push_back(C);
      if (auto *C = OMPClauseWithPostUpdate::get(Clause)) {
        if (Expr *E = C->getPostUpdateExpr())
          MarkDeclarationsReferencedInExpr(E);
      }
    }
    if (Clause->getClauseKind() == OMPC_schedule)
      SC = cast<OMPScheduleClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_ordered)
      OC = cast<OMPOrderedClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_linear)
      LCs.push_back(cast<OMPLinearClause>(Clause));
  }
  // Capture allocator expressions if used.
  for (Expr *E : DSAStack->getInnerAllocators())
    MarkDeclarationsReferencedInExpr(E);
  // OpenMP, 2.7.1 Loop Construct, Restrictions
  // The nonmonotonic modifier cannot be specified if an ordered clause is
  // specified.
  if (SC &&
      (SC->getFirstScheduleModifier() == OMPC_SCHEDULE_MODIFIER_nonmonotonic ||
       SC->getSecondScheduleModifier() ==
           OMPC_SCHEDULE_MODIFIER_nonmonotonic) &&
      OC) {
    Diag(SC->getFirstScheduleModifier() == OMPC_SCHEDULE_MODIFIER_nonmonotonic
             ? SC->getFirstScheduleModifierLoc()
             : SC->getSecondScheduleModifierLoc(),
         diag::err_omp_simple_clause_incompatible_with_ordered)
        << getOpenMPClauseName(OMPC_schedule)
        << getOpenMPSimpleClauseTypeName(OMPC_schedule,
                                         OMPC_SCHEDULE_MODIFIER_nonmonotonic)
        << SourceRange(OC->getBeginLoc(), OC->getEndLoc());
    ErrorFound = true;
  }
  // OpenMP 5.0, 2.9.2 Worksharing-Loop Construct, Restrictions.
  // If an order(concurrent) clause is present, an ordered clause may not appear
  // on the same directive.
  if (checkOrderedOrderSpecified(*this, Clauses))
    ErrorFound = true;
  if (!LCs.empty() && OC && OC->getNumForLoops()) {
    for (const OMPLinearClause *C : LCs) {
      Diag(C->getBeginLoc(), diag::err_omp_linear_ordered)
          << SourceRange(OC->getBeginLoc(), OC->getEndLoc());
    }
    ErrorFound = true;
  }
  if (isOpenMPWorksharingDirective(DSAStack->getCurrentDirective()) &&
      isOpenMPSimdDirective(DSAStack->getCurrentDirective()) && OC &&
      OC->getNumForLoops()) {
    Diag(OC->getBeginLoc(), diag::err_omp_ordered_simd)
        << getOpenMPDirectiveName(DSAStack->getCurrentDirective());
    ErrorFound = true;
  }
  if (ErrorFound) {
    return StmtError();
  }
  StmtResult SR = S;
  unsigned CompletedRegions = 0;
  for (OpenMPDirectiveKind ThisCaptureRegion : llvm::reverse(CaptureRegions)) {
    // Mark all variables in private list clauses as used in inner region.
    // Required for proper codegen of combined directives.
    // TODO: add processing for other clauses.
    if (ThisCaptureRegion != OMPD_unknown) {
      for (const clang::OMPClauseWithPreInit *C : PICs) {
        OpenMPDirectiveKind CaptureRegion = C->getCaptureRegion();
        // Find the particular capture region for the clause if the
        // directive is a combined one with multiple capture regions.
        // If the directive is not a combined one, the capture region
        // associated with the clause is OMPD_unknown and is generated
        // only once.
        if (CaptureRegion == ThisCaptureRegion ||
            CaptureRegion == OMPD_unknown) {
          if (auto *DS = cast_or_null<DeclStmt>(C->getPreInitStmt())) {
            for (Decl *D : DS->decls())
              MarkVariableReferenced(D->getLocation(), cast<VarDecl>(D));
          }
        }
      }
    }
    if (ThisCaptureRegion == OMPD_target) {
      // Capture allocator traits in the target region. They are used implicitly
      // and, thus, are not captured by default.
      for (OMPClause *C : Clauses) {
        if (const auto *UAC = dyn_cast<OMPUsesAllocatorsClause>(C)) {
          for (unsigned I = 0, End = UAC->getNumberOfAllocators(); I < End;
               ++I) {
            OMPUsesAllocatorsClause::Data D = UAC->getAllocatorData(I);
            if (Expr *E = D.AllocatorTraits)
              MarkDeclarationsReferencedInExpr(E);
          }
          continue;
        }
      }
    }
    if (ThisCaptureRegion == OMPD_parallel) {
      // Capture temp arrays for inscan reductions and locals in aligned
      // clauses.
      for (OMPClause *C : Clauses) {
        if (auto *RC = dyn_cast<OMPReductionClause>(C)) {
          if (RC->getModifier() != OMPC_REDUCTION_inscan)
            continue;
          for (Expr *E : RC->copy_array_temps())
            MarkDeclarationsReferencedInExpr(E);
        }
        if (auto *AC = dyn_cast<OMPAlignedClause>(C)) {
          for (Expr *E : AC->varlists())
            MarkDeclarationsReferencedInExpr(E);
        }
      }
    }
    if (++CompletedRegions == CaptureRegions.size())
      DSAStack->setBodyComplete();
    SR = ActOnCapturedRegionEnd(SR.get());
  }
  return SR;
}
 
static bool checkCancelRegion(Sema &SemaRef, OpenMPDirectiveKind CurrentRegion,
                              OpenMPDirectiveKind CancelRegion,
                              SourceLocation StartLoc) {
  // CancelRegion is only needed for cancel and cancellation_point.
  if (CurrentRegion != OMPD_cancel && CurrentRegion != OMPD_cancellation_point)
    return false;
 
  if (CancelRegion == OMPD_parallel || CancelRegion == OMPD_for ||
      CancelRegion == OMPD_sections || CancelRegion == OMPD_taskgroup)
    return false;
 
  SemaRef.Diag(StartLoc, diag::err_omp_wrong_cancel_region)
      << getOpenMPDirectiveName(CancelRegion);
  return true;
}
 
static bool checkNestingOfRegions(Sema &SemaRef, const DSAStackTy *Stack,
                                  OpenMPDirectiveKind CurrentRegion,
                                  const DeclarationNameInfo &CurrentName,
                                  OpenMPDirectiveKind CancelRegion,
                                  OpenMPBindClauseKind BindKind,
                                  SourceLocation StartLoc) {
  if (Stack->getCurScope()) {
    OpenMPDirectiveKind ParentRegion = Stack->getParentDirective();
    OpenMPDirectiveKind OffendingRegion = ParentRegion;
    bool NestingProhibited = false;
    bool CloseNesting = true;
    bool OrphanSeen = false;
    enum {
      NoRecommend,
      ShouldBeInParallelRegion,
      ShouldBeInOrderedRegion,
      ShouldBeInTargetRegion,
      ShouldBeInTeamsRegion,
      ShouldBeInLoopSimdRegion,
    } Recommend = NoRecommend;
    if (isOpenMPSimdDirective(ParentRegion) &&
        ((SemaRef.LangOpts.OpenMP <= 45 && CurrentRegion != OMPD_ordered) ||
         (SemaRef.LangOpts.OpenMP >= 50 && CurrentRegion != OMPD_ordered &&
          CurrentRegion != OMPD_simd && CurrentRegion != OMPD_atomic &&
          CurrentRegion != OMPD_scan))) {
      // OpenMP [2.16, Nesting of Regions]
      // OpenMP constructs may not be nested inside a simd region.
      // OpenMP [2.8.1,simd Construct, Restrictions]
      // An ordered construct with the simd clause is the only OpenMP
      // construct that can appear in the simd region.
      // Allowing a SIMD construct nested in another SIMD construct is an
      // extension. The OpenMP 4.5 spec does not allow it. Issue a warning
      // message.
      // OpenMP 5.0 [2.9.3.1, simd Construct, Restrictions]
      // The only OpenMP constructs that can be encountered during execution of
      // a simd region are the atomic construct, the loop construct, the simd
      // construct and the ordered construct with the simd clause.
      SemaRef.Diag(StartLoc, (CurrentRegion != OMPD_simd)
                                 ? diag::err_omp_prohibited_region_simd
                                 : diag::warn_omp_nesting_simd)
          << (SemaRef.LangOpts.OpenMP >= 50 ? 1 : 0);
      return CurrentRegion != OMPD_simd;
    }
    if (ParentRegion == OMPD_atomic) {
      // OpenMP [2.16, Nesting of Regions]
      // OpenMP constructs may not be nested inside an atomic region.
      SemaRef.Diag(StartLoc, diag::err_omp_prohibited_region_atomic);
      return true;
    }
    if (CurrentRegion == OMPD_section) {
      // OpenMP [2.7.2, sections Construct, Restrictions]
      // Orphaned section directives are prohibited. That is, the section
      // directives must appear within the sections construct and must not be
      // encountered elsewhere in the sections region.
      if (ParentRegion != OMPD_sections &&
          ParentRegion != OMPD_parallel_sections) {
        SemaRef.Diag(StartLoc, diag::err_omp_orphaned_section_directive)
            << (ParentRegion != OMPD_unknown)
            << getOpenMPDirectiveName(ParentRegion);
        return true;
      }
      return false;
    }
    // Allow some constructs (except teams and cancellation constructs) to be
    // orphaned (they could be used in functions, called from OpenMP regions
    // with the required preconditions).
    if (ParentRegion == OMPD_unknown &&
        !isOpenMPNestingTeamsDirective(CurrentRegion) &&
        CurrentRegion != OMPD_cancellation_point &&
        CurrentRegion != OMPD_cancel && CurrentRegion != OMPD_scan)
      return false;
    if (CurrentRegion == OMPD_cancellation_point ||
        CurrentRegion == OMPD_cancel) {
      // OpenMP [2.16, Nesting of Regions]
      // A cancellation point construct for which construct-type-clause is
      // taskgroup must be nested inside a task construct. A cancellation
      // point construct for which construct-type-clause is not taskgroup must
      // be closely nested inside an OpenMP construct that matches the type
      // specified in construct-type-clause.
      // A cancel construct for which construct-type-clause is taskgroup must be
      // nested inside a task construct. A cancel construct for which
      // construct-type-clause is not taskgroup must be closely nested inside an
      // OpenMP construct that matches the type specified in
      // construct-type-clause.
      NestingProhibited =
          !((CancelRegion == OMPD_parallel &&
             (ParentRegion == OMPD_parallel ||
              ParentRegion == OMPD_target_parallel)) ||
            (CancelRegion == OMPD_for &&
             (ParentRegion == OMPD_for || ParentRegion == OMPD_parallel_for ||
              ParentRegion == OMPD_target_parallel_for ||
              ParentRegion == OMPD_distribute_parallel_for ||
              ParentRegion == OMPD_teams_distribute_parallel_for ||
              ParentRegion == OMPD_target_teams_distribute_parallel_for)) ||
            (CancelRegion == OMPD_taskgroup &&
             (ParentRegion == OMPD_task ||
              (SemaRef.getLangOpts().OpenMP >= 50 &&
               (ParentRegion == OMPD_taskloop ||
                ParentRegion == OMPD_master_taskloop ||
                ParentRegion == OMPD_masked_taskloop ||
                ParentRegion == OMPD_parallel_masked_taskloop ||
                ParentRegion == OMPD_parallel_master_taskloop)))) ||
            (CancelRegion == OMPD_sections &&
             (ParentRegion == OMPD_section || ParentRegion == OMPD_sections ||
              ParentRegion == OMPD_parallel_sections)));
      OrphanSeen = ParentRegion == OMPD_unknown;
    } else if (CurrentRegion == OMPD_master || CurrentRegion == OMPD_masked) {
      // OpenMP 5.1 [2.22, Nesting of Regions]
      // A masked region may not be closely nested inside a worksharing, loop,
      // atomic, task, or taskloop region.
      NestingProhibited = isOpenMPWorksharingDirective(ParentRegion) ||
                          isOpenMPGenericLoopDirective(ParentRegion) ||
                          isOpenMPTaskingDirective(ParentRegion);
    } else if (CurrentRegion == OMPD_critical && CurrentName.getName()) {
      // OpenMP [2.16, Nesting of Regions]
      // A critical region may not be nested (closely or otherwise) inside a
      // critical region with the same name. Note that this restriction is not
      // sufficient to prevent deadlock.
      SourceLocation PreviousCriticalLoc;
      bool DeadLock = Stack->hasDirective(
          [CurrentName, &PreviousCriticalLoc](OpenMPDirectiveKind K,
                                              const DeclarationNameInfo &DNI,
                                              SourceLocation Loc) {
            if (K == OMPD_critical && DNI.getName() == CurrentName.getName()) {
              PreviousCriticalLoc = Loc;
              return true;
            }
            return false;
          },
          false /* skip top directive */);
      if (DeadLock) {
        SemaRef.Diag(StartLoc,
                     diag::err_omp_prohibited_region_critical_same_name)
            << CurrentName.getName();
        if (PreviousCriticalLoc.isValid())
          SemaRef.Diag(PreviousCriticalLoc,
                       diag::note_omp_previous_critical_region);
        return true;
      }
    } else if (CurrentRegion == OMPD_barrier) {
      // OpenMP 5.1 [2.22, Nesting of Regions]
      // A barrier region may not be closely nested inside a worksharing, loop,
      // task, taskloop, critical, ordered, atomic, or masked region.
      NestingProhibited =
          isOpenMPWorksharingDirective(ParentRegion) ||
          isOpenMPGenericLoopDirective(ParentRegion) ||
          isOpenMPTaskingDirective(ParentRegion) ||
          ParentRegion == OMPD_master || ParentRegion == OMPD_masked ||
          ParentRegion == OMPD_parallel_master ||
          ParentRegion == OMPD_parallel_masked ||
          ParentRegion == OMPD_critical || ParentRegion == OMPD_ordered;
    } else if (isOpenMPWorksharingDirective(CurrentRegion) &&
               !isOpenMPParallelDirective(CurrentRegion) &&
               !isOpenMPTeamsDirective(CurrentRegion)) {
      // OpenMP 5.1 [2.22, Nesting of Regions]
      // A loop region that binds to a parallel region or a worksharing region
      // may not be closely nested inside a worksharing, loop, task, taskloop,
      // critical, ordered, atomic, or masked region.
      NestingProhibited =
          isOpenMPWorksharingDirective(ParentRegion) ||
          isOpenMPGenericLoopDirective(ParentRegion) ||
          isOpenMPTaskingDirective(ParentRegion) ||
          ParentRegion == OMPD_master || ParentRegion == OMPD_masked ||
          ParentRegion == OMPD_parallel_master ||
          ParentRegion == OMPD_parallel_masked ||
          ParentRegion == OMPD_critical || ParentRegion == OMPD_ordered;
      Recommend = ShouldBeInParallelRegion;
    } else if (CurrentRegion == OMPD_ordered) {
      // OpenMP [2.16, Nesting of Regions]
      // An ordered region may not be closely nested inside a critical,
      // atomic, or explicit task region.
      // An ordered region must be closely nested inside a loop region (or
      // parallel loop region) with an ordered clause.
      // OpenMP [2.8.1,simd Construct, Restrictions]
      // An ordered construct with the simd clause is the only OpenMP construct
      // that can appear in the simd region.
      NestingProhibited = ParentRegion == OMPD_critical ||
                          isOpenMPTaskingDirective(ParentRegion) ||
                          !(isOpenMPSimdDirective(ParentRegion) ||
                            Stack->isParentOrderedRegion());
      Recommend = ShouldBeInOrderedRegion;
    } else if (isOpenMPNestingTeamsDirective(CurrentRegion)) {
      // OpenMP [2.16, Nesting of Regions]
      // If specified, a teams construct must be contained within a target
      // construct.
      NestingProhibited =
          (SemaRef.LangOpts.OpenMP <= 45 && ParentRegion != OMPD_target) ||
          (SemaRef.LangOpts.OpenMP >= 50 && ParentRegion != OMPD_unknown &&
           ParentRegion != OMPD_target);
      OrphanSeen = ParentRegion == OMPD_unknown;
      Recommend = ShouldBeInTargetRegion;
    } else if (CurrentRegion == OMPD_scan) {
      // OpenMP [2.16, Nesting of Regions]
      // If specified, a teams construct must be contained within a target
      // construct.
      NestingProhibited =
          SemaRef.LangOpts.OpenMP < 50 ||
          (ParentRegion != OMPD_simd && ParentRegion != OMPD_for &&
           ParentRegion != OMPD_for_simd && ParentRegion != OMPD_parallel_for &&
           ParentRegion != OMPD_parallel_for_simd);
      OrphanSeen = ParentRegion == OMPD_unknown;
      Recommend = ShouldBeInLoopSimdRegion;
    }
    if (!NestingProhibited &&
        !isOpenMPTargetExecutionDirective(CurrentRegion) &&
        !isOpenMPTargetDataManagementDirective(CurrentRegion) &&
        (ParentRegion == OMPD_teams || ParentRegion == OMPD_target_teams)) {
      // OpenMP [5.1, 2.22, Nesting of Regions]
      // distribute, distribute simd, distribute parallel worksharing-loop,
      // distribute parallel worksharing-loop SIMD, loop, parallel regions,
      // including any parallel regions arising from combined constructs,
      // omp_get_num_teams() regions, and omp_get_team_num() regions are the
      // only OpenMP regions that may be strictly nested inside the teams
      // region.
      //
      // As an extension, we permit atomic within teams as well.
      NestingProhibited = !isOpenMPParallelDirective(CurrentRegion) &&
                          !isOpenMPDistributeDirective(CurrentRegion) &&
                          CurrentRegion != OMPD_loop &&
                          !(SemaRef.getLangOpts().OpenMPExtensions &&
                            CurrentRegion == OMPD_atomic);
      Recommend = ShouldBeInParallelRegion;
    }
    if (!NestingProhibited && CurrentRegion == OMPD_loop) {
      // OpenMP [5.1, 2.11.7, loop Construct, Restrictions]
      // If the bind clause is present on the loop construct and binding is
      // teams then the corresponding loop region must be strictly nested inside
      // a teams region.
      NestingProhibited = BindKind == OMPC_BIND_teams &&
                          ParentRegion != OMPD_teams &&
                          ParentRegion != OMPD_target_teams;
      Recommend = ShouldBeInTeamsRegion;
    }
    if (!NestingProhibited &&
        isOpenMPNestingDistributeDirective(CurrentRegion)) {
      // OpenMP 4.5 [2.17 Nesting of Regions]
      // The region associated with the distribute construct must be strictly
      // nested inside a teams region
      NestingProhibited =
          (ParentRegion != OMPD_teams && ParentRegion != OMPD_target_teams);
      Recommend = ShouldBeInTeamsRegion;
    }
    if (!NestingProhibited &&
        (isOpenMPTargetExecutionDirective(CurrentRegion) ||
         isOpenMPTargetDataManagementDirective(CurrentRegion))) {
      // OpenMP 4.5 [2.17 Nesting of Regions]
      // If a target, target update, target data, target enter data, or
      // target exit data construct is encountered during execution of a
      // target region, the behavior is unspecified.
      NestingProhibited = Stack->hasDirective(
          [&OffendingRegion](OpenMPDirectiveKind K, const DeclarationNameInfo &,
                             SourceLocation) {
            if (isOpenMPTargetExecutionDirective(K)) {
              OffendingRegion = K;
              return true;
            }
            return false;
          },
          false /* don't skip top directive */);
      CloseNesting = false;
    }
    if (NestingProhibited) {
      if (OrphanSeen) {
        SemaRef.Diag(StartLoc, diag::err_omp_orphaned_device_directive)
            << getOpenMPDirectiveName(CurrentRegion) << Recommend;
      } else {
        SemaRef.Diag(StartLoc, diag::err_omp_prohibited_region)
            << CloseNesting << getOpenMPDirectiveName(OffendingRegion)
            << Recommend << getOpenMPDirectiveName(CurrentRegion);
      }
      return true;
    }
  }
  return false;
}
 
struct Kind2Unsigned {
  using argument_type = OpenMPDirectiveKind;
  unsigned operator()(argument_type DK) { return unsigned(DK); }
};
static bool checkIfClauses(Sema &S, OpenMPDirectiveKind Kind,
                           ArrayRef<OMPClause *> Clauses,
                           ArrayRef<OpenMPDirectiveKind> AllowedNameModifiers) {
  bool ErrorFound = false;
  unsigned NamedModifiersNumber = 0;
  llvm::IndexedMap<const OMPIfClause *, Kind2Unsigned> FoundNameModifiers;
  FoundNameModifiers.resize(llvm::omp::Directive_enumSize + 1);
  SmallVector<SourceLocation, 4> NameModifierLoc;
  for (const OMPClause *C : Clauses) {
    if (const auto *IC = dyn_cast_or_null<OMPIfClause>(C)) {
      // At most one if clause without a directive-name-modifier can appear on
      // the directive.
      OpenMPDirectiveKind CurNM = IC->getNameModifier();
      if (FoundNameModifiers[CurNM]) {
        S.Diag(C->getBeginLoc(), diag::err_omp_more_one_clause)
            << getOpenMPDirectiveName(Kind) << getOpenMPClauseName(OMPC_if)
            << (CurNM != OMPD_unknown) << getOpenMPDirectiveName(CurNM);
        ErrorFound = true;
      } else if (CurNM != OMPD_unknown) {
        NameModifierLoc.push_back(IC->getNameModifierLoc());
        ++NamedModifiersNumber;
      }
      FoundNameModifiers[CurNM] = IC;
      if (CurNM == OMPD_unknown)
        continue;
      // Check if the specified name modifier is allowed for the current
      // directive.
      // At most one if clause with the particular directive-name-modifier can
      // appear on the directive.
      if (!llvm::is_contained(AllowedNameModifiers, CurNM)) {
        S.Diag(IC->getNameModifierLoc(),
               diag::err_omp_wrong_if_directive_name_modifier)
            << getOpenMPDirectiveName(CurNM) << getOpenMPDirectiveName(Kind);
        ErrorFound = true;
      }
    }
  }
  // If any if clause on the directive includes a directive-name-modifier then
  // all if clauses on the directive must include a directive-name-modifier.
  if (FoundNameModifiers[OMPD_unknown] && NamedModifiersNumber > 0) {
    if (NamedModifiersNumber == AllowedNameModifiers.size()) {
      S.Diag(FoundNameModifiers[OMPD_unknown]->getBeginLoc(),
             diag::err_omp_no_more_if_clause);
    } else {
      std::string Values;
      std::string Sep(", ");
      unsigned AllowedCnt = 0;
      unsigned TotalAllowedNum =
          AllowedNameModifiers.size() - NamedModifiersNumber;
      for (unsigned Cnt = 0, End = AllowedNameModifiers.size(); Cnt < End;
           ++Cnt) {
        OpenMPDirectiveKind NM = AllowedNameModifiers[Cnt];
        if (!FoundNameModifiers[NM]) {
          Values += "'";
          Values += getOpenMPDirectiveName(NM);
          Values += "'";
          if (AllowedCnt + 2 == TotalAllowedNum)
            Values += " or ";
          else if (AllowedCnt + 1 != TotalAllowedNum)
            Values += Sep;
          ++AllowedCnt;
        }
      }
      S.Diag(FoundNameModifiers[OMPD_unknown]->getCondition()->getBeginLoc(),
             diag::err_omp_unnamed_if_clause)
          << (TotalAllowedNum > 1) << Values;
    }
    for (SourceLocation Loc : NameModifierLoc) {
      S.Diag(Loc, diag::note_omp_previous_named_if_clause);
    }
    ErrorFound = true;
  }
  return ErrorFound;
}
 
static std::pair<ValueDecl *, bool> getPrivateItem(Sema &S, Expr *&RefExpr,
                                                   SourceLocation &ELoc,
                                                   SourceRange &ERange,
                                                   bool AllowArraySection,
                                                   StringRef DiagType) {
  if (RefExpr->isTypeDependent() || RefExpr->isValueDependent() ||
      RefExpr->containsUnexpandedParameterPack())
    return std::make_pair(nullptr, true);
 
  // OpenMP [3.1, C/C++]
  //  A list item is a variable name.
  // OpenMP  [2.9.3.3, Restrictions, p.1]
  //  A variable that is part of another variable (as an array or
  //  structure element) cannot appear in a private clause.
  RefExpr = RefExpr->IgnoreParens();
  enum {
    NoArrayExpr = -1,
    ArraySubscript = 0,
    OMPArraySection = 1
  } IsArrayExpr = NoArrayExpr;
  if (AllowArraySection) {
    if (auto *ASE = dyn_cast_or_null<ArraySubscriptExpr>(RefExpr)) {
      Expr *Base = ASE->getBase()->IgnoreParenImpCasts();
      while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
        Base = TempASE->getBase()->IgnoreParenImpCasts();
      RefExpr = Base;
      IsArrayExpr = ArraySubscript;
    } else if (auto *OASE = dyn_cast_or_null<OMPArraySectionExpr>(RefExpr)) {
      Expr *Base = OASE->getBase()->IgnoreParenImpCasts();
      while (auto *TempOASE = dyn_cast<OMPArraySectionExpr>(Base))
        Base = TempOASE->getBase()->IgnoreParenImpCasts();
      while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
        Base = TempASE->getBase()->IgnoreParenImpCasts();
      RefExpr = Base;
      IsArrayExpr = OMPArraySection;
    }
  }
  ELoc = RefExpr->getExprLoc();
  ERange = RefExpr->getSourceRange();
  RefExpr = RefExpr->IgnoreParenImpCasts();
  auto *DE = dyn_cast_or_null<DeclRefExpr>(RefExpr);
  auto *ME = dyn_cast_or_null<MemberExpr>(RefExpr);
  if ((!DE || !isa<VarDecl>(DE->getDecl())) &&
      (S.getCurrentThisType().isNull() || !ME ||
       !isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()) ||
       !isa<FieldDecl>(ME->getMemberDecl()))) {
    if (IsArrayExpr != NoArrayExpr) {
      S.Diag(ELoc, diag::err_omp_expected_base_var_name)
          << IsArrayExpr << ERange;
    } else if (!DiagType.empty()) {
      unsigned DiagSelect = S.getLangOpts().CPlusPlus
                                ? (S.getCurrentThisType().isNull() ? 1 : 2)
                                : 0;
      S.Diag(ELoc, diag::err_omp_expected_var_name_member_expr_with_type)
          << DiagSelect << DiagType << ERange;
    } else {
      S.Diag(ELoc,
             AllowArraySection
                 ? diag::err_omp_expected_var_name_member_expr_or_array_item
                 : diag::err_omp_expected_var_name_member_expr)
          << (S.getCurrentThisType().isNull() ? 0 : 1) << ERange;
    }
    return std::make_pair(nullptr, false);
  }
  return std::make_pair(
      getCanonicalDecl(DE ? DE->getDecl() : ME->getMemberDecl()), false);
}
 
namespace {
/// Checks if the allocator is used in uses_allocators clause to be allowed in
/// target regions.
class AllocatorChecker final : public ConstStmtVisitor<AllocatorChecker, bool> {
  DSAStackTy *S = nullptr;
 
public:
  bool VisitDeclRefExpr(const DeclRefExpr *E) {
    return S->isUsesAllocatorsDecl(E->getDecl())
               .value_or(DSAStackTy::UsesAllocatorsDeclKind::AllocatorTrait) ==
           DSAStackTy::UsesAllocatorsDeclKind::AllocatorTrait;
  }
  bool VisitStmt(const Stmt *S) {
    for (const Stmt *Child : S->children()) {
      if (Child && Visit(Child))
        return true;
    }
    return false;
  }
  explicit AllocatorChecker(DSAStackTy *S) : S(S) {}
};
} // namespace
 
static void checkAllocateClauses(Sema &S, DSAStackTy *Stack,
                                 ArrayRef<OMPClause *> Clauses) {
  assert(!S.CurContext->isDependentContext() &&
         "Expected non-dependent context.");
  auto AllocateRange =
      llvm::make_filter_range(Clauses, OMPAllocateClause::classof);
  llvm::DenseMap<CanonicalDeclPtr<Decl>, CanonicalDeclPtr<VarDecl>> DeclToCopy;
  auto PrivateRange = llvm::make_filter_range(Clauses, [](const OMPClause *C) {
    return isOpenMPPrivate(C->getClauseKind());
  });
  for (OMPClause *Cl : PrivateRange) {
    MutableArrayRef<Expr *>::iterator I, It, Et;
    if (Cl->getClauseKind() == OMPC_private) {
      auto *PC = cast<OMPPrivateClause>(Cl);
      I = PC->private_copies().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_firstprivate) {
      auto *PC = cast<OMPFirstprivateClause>(Cl);
      I = PC->private_copies().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_lastprivate) {
      auto *PC = cast<OMPLastprivateClause>(Cl);
      I = PC->private_copies().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_linear) {
      auto *PC = cast<OMPLinearClause>(Cl);
      I = PC->privates().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_reduction) {
      auto *PC = cast<OMPReductionClause>(Cl);
      I = PC->privates().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_task_reduction) {
      auto *PC = cast<OMPTaskReductionClause>(Cl);
      I = PC->privates().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else if (Cl->getClauseKind() == OMPC_in_reduction) {
      auto *PC = cast<OMPInReductionClause>(Cl);
      I = PC->privates().begin();
      It = PC->varlist_begin();
      Et = PC->varlist_end();
    } else {
      llvm_unreachable("Expected private clause.");
    }
    for (Expr *E : llvm::make_range(It, Et)) {
      if (!*I) {
        ++I;
        continue;
      }
      SourceLocation ELoc;
      SourceRange ERange;
      Expr *SimpleRefExpr = E;
      auto Res = getPrivateItem(S, SimpleRefExpr, ELoc, ERange,
                                /*AllowArraySection=*/true);
      DeclToCopy.try_emplace(Res.first,
                             cast<VarDecl>(cast<DeclRefExpr>(*I)->getDecl()));
      ++I;
    }
  }
  for (OMPClause *C : AllocateRange) {
    auto *AC = cast<OMPAllocateClause>(C);
    if (S.getLangOpts().OpenMP >= 50 &&
        !Stack->hasRequiresDeclWithClause<OMPDynamicAllocatorsClause>() &&
        isOpenMPTargetExecutionDirective(Stack->getCurrentDirective()) &&
        AC->getAllocator()) {
      Expr *Allocator = AC->getAllocator();
      // OpenMP, 2.12.5 target Construct
      // Memory allocators that do not appear in a uses_allocators clause cannot
      // appear as an allocator in an allocate clause or be used in the target
      // region unless a requires directive with the dynamic_allocators clause
      // is present in the same compilation unit.
      AllocatorChecker Checker(Stack);
      if (Checker.Visit(Allocator))
        S.Diag(Allocator->getExprLoc(),
               diag::err_omp_allocator_not_in_uses_allocators)
            << Allocator->getSourceRange();
    }
    OMPAllocateDeclAttr::AllocatorTypeTy AllocatorKind =
        getAllocatorKind(S, Stack, AC->getAllocator());
    // OpenMP, 2.11.4 allocate Clause, Restrictions.
    // For task, taskloop or target directives, allocation requests to memory
    // allocators with the trait access set to thread result in unspecified
    // behavior.
    if (AllocatorKind == OMPAllocateDeclAttr::OMPThreadMemAlloc &&
        (isOpenMPTaskingDirective(Stack->getCurrentDirective()) ||
         isOpenMPTargetExecutionDirective(Stack->getCurrentDirective()))) {
      S.Diag(AC->getAllocator()->getExprLoc(),
             diag::warn_omp_allocate_thread_on_task_target_directive)
          << getOpenMPDirectiveName(Stack->getCurrentDirective());
    }
    for (Expr *E : AC->varlists()) {
      SourceLocation ELoc;
      SourceRange ERange;
      Expr *SimpleRefExpr = E;
      auto Res = getPrivateItem(S, SimpleRefExpr, ELoc, ERange);
      ValueDecl *VD = Res.first;
      DSAStackTy::DSAVarData Data = Stack->getTopDSA(VD, /*FromParent=*/false);
      if (!isOpenMPPrivate(Data.CKind)) {
        S.Diag(E->getExprLoc(),
               diag::err_omp_expected_private_copy_for_allocate);
        continue;
      }
      VarDecl *PrivateVD = DeclToCopy[VD];
      if (checkPreviousOMPAllocateAttribute(S, Stack, E, PrivateVD,
                                            AllocatorKind, AC->getAllocator()))
        continue;
      // Placeholder until allocate clause supports align modifier.
      Expr *Alignment = nullptr;
      applyOMPAllocateAttribute(S, PrivateVD, AllocatorKind, AC->getAllocator(),
                                Alignment, E->getSourceRange());
    }
  }
}
 
namespace {
/// Rewrite statements and expressions for Sema \p Actions CurContext.
///
/// Used to wrap already parsed statements/expressions into a new CapturedStmt
/// context. DeclRefExpr used inside the new context are changed to refer to the
/// captured variable instead.
class CaptureVars : public TreeTransform<CaptureVars> {
  using BaseTransform = TreeTransform<CaptureVars>;
 
public:
  CaptureVars(Sema &Actions) : BaseTransform(Actions) {}
 
  bool AlwaysRebuild() { return true; }
};
} // namespace
 
static VarDecl *precomputeExpr(Sema &Actions,
                               SmallVectorImpl<Stmt *> &BodyStmts, Expr *E,
                               StringRef Name) {
  Expr *NewE = AssertSuccess(CaptureVars(Actions).TransformExpr(E));
  VarDecl *NewVar = buildVarDecl(Actions, {}, NewE->getType(), Name, nullptr,
                                 dyn_cast<DeclRefExpr>(E->IgnoreImplicit()));
  auto *NewDeclStmt = cast<DeclStmt>(AssertSuccess(
      Actions.ActOnDeclStmt(Actions.ConvertDeclToDeclGroup(NewVar), {}, {})));
  Actions.AddInitializerToDecl(NewDeclStmt->getSingleDecl(), NewE, false);
  BodyStmts.push_back(NewDeclStmt);
  return NewVar;
}
 
/// Create a closure that computes the number of iterations of a loop.
///
/// \param Actions   The Sema object.
/// \param LogicalTy Type for the logical iteration number.
/// \param Rel       Comparison operator of the loop condition.
/// \param StartExpr Value of the loop counter at the first iteration.
/// \param StopExpr  Expression the loop counter is compared against in the loop
/// condition. \param StepExpr      Amount of increment after each iteration.
///
/// \return Closure (CapturedStmt) of the distance calculation.
static CapturedStmt *buildDistanceFunc(Sema &Actions, QualType LogicalTy,
                                       BinaryOperator::Opcode Rel,
                                       Expr *StartExpr, Expr *StopExpr,
                                       Expr *StepExpr) {
  ASTContext &Ctx = Actions.getASTContext();
  TypeSourceInfo *LogicalTSI = Ctx.getTrivialTypeSourceInfo(LogicalTy);
 
  // Captured regions currently don't support return values, we use an
  // out-parameter instead. All inputs are implicit captures.
  // TODO: Instead of capturing each DeclRefExpr occurring in
  // StartExpr/StopExpr/Step, these could also be passed as a value capture.
  QualType ResultTy = Ctx.getLValueReferenceType(LogicalTy);
  Sema::CapturedParamNameType Params[] = {{"Distance", ResultTy},
                                          {StringRef(), QualType()}};
  Actions.ActOnCapturedRegionStart({}, nullptr, CR_Default, Params);
 
  Stmt *Body;
  {
    Sema::CompoundScopeRAII CompoundScope(Actions);
    CapturedDecl *CS = cast<CapturedDecl>(Actions.CurContext);
 
    // Get the LValue expression for the result.
    ImplicitParamDecl *DistParam = CS->getParam(0);
    DeclRefExpr *DistRef = Actions.BuildDeclRefExpr(
        DistParam, LogicalTy, VK_LValue, {}, nullptr, nullptr, {}, nullptr);
 
    SmallVector<Stmt *, 4> BodyStmts;
 
    // Capture all referenced variable references.
    // TODO: Instead of computing NewStart/NewStop/NewStep inside the
    // CapturedStmt, we could compute them before and capture the result, to be
    // used jointly with the LoopVar function.
    VarDecl *NewStart = precomputeExpr(Actions, BodyStmts, StartExpr, ".start");
    VarDecl *NewStop = precomputeExpr(Actions, BodyStmts, StopExpr, ".stop");
    VarDecl *NewStep = precomputeExpr(Actions, BodyStmts, StepExpr, ".step");
    auto BuildVarRef = [&](VarDecl *VD) {
      return buildDeclRefExpr(Actions, VD, VD->getType(), {});
    };
 
    IntegerLiteral *Zero = IntegerLiteral::Create(
        Ctx, llvm::APInt(Ctx.getIntWidth(LogicalTy), 0), LogicalTy, {});
    IntegerLiteral *One = IntegerLiteral::Create(
        Ctx, llvm::APInt(Ctx.getIntWidth(LogicalTy), 1), LogicalTy, {});
    Expr *Dist;
    if (Rel == BO_NE) {
      // When using a != comparison, the increment can be +1 or -1. This can be
      // dynamic at runtime, so we need to check for the direction.
      Expr *IsNegStep = AssertSuccess(
          Actions.BuildBinOp(nullptr, {}, BO_LT, BuildVarRef(NewStep), Zero));
 
      // Positive increment.
      Expr *ForwardRange = AssertSuccess(Actions.BuildBinOp(
          nullptr, {}, BO_Sub, BuildVarRef(NewStop), BuildVarRef(NewStart)));
      ForwardRange = AssertSuccess(
          Actions.BuildCStyleCastExpr({}, LogicalTSI, {}, ForwardRange));
      Expr *ForwardDist = AssertSuccess(Actions.BuildBinOp(
          nullptr, {}, BO_Div, ForwardRange, BuildVarRef(NewStep)));
 
      // Negative increment.
      Expr *BackwardRange = AssertSuccess(Actions.BuildBinOp(
          nullptr, {}, BO_Sub, BuildVarRef(NewStart), BuildVarRef(NewStop)));
      BackwardRange = AssertSuccess(
          Actions.BuildCStyleCastExpr({}, LogicalTSI, {}, BackwardRange));
      Expr *NegIncAmount = AssertSuccess(
          Actions.BuildUnaryOp(nullptr, {}, UO_Minus, BuildVarRef(NewStep)));
      Expr *BackwardDist = AssertSuccess(
          Actions.BuildBinOp(nullptr, {}, BO_Div, BackwardRange, NegIncAmount));
 
      // Use the appropriate case.
      Dist = AssertSuccess(Actions.ActOnConditionalOp(
          {}, {}, IsNegStep, BackwardDist, ForwardDist));
    } else {
      assert((Rel == BO_LT || Rel == BO_LE || Rel == BO_GE || Rel == BO_GT) &&
             "Expected one of these relational operators");
 
      // We can derive the direction from any other comparison operator. It is
      // non well-formed OpenMP if Step increments/decrements in the other
      // directions. Whether at least the first iteration passes the loop