OpenMPClause.h

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//===- OpenMPClause.h - Classes for OpenMP clauses --------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// This file defines OpenMP AST classes for clauses.
/// There are clauses for executable directives, clauses for declarative
/// directives and clauses which can be used in both kinds of directives.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_OPENMPCLAUSE_H
#define LLVM_CLANG_AST_OPENMPCLAUSE_H

#include "clang/AST/Decl.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/StmtIterator.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/OpenMPKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/TrailingObjects.h"
#include <cassert>
#include <cstddef>
#include <iterator>
#include <utility>

namespace clang {

class ASTContext;

//===----------------------------------------------------------------------===//
// AST classes for clauses.
//===----------------------------------------------------------------------===//

/// This is a basic class for representing single OpenMP clause.
class OMPClause {
  /// Starting location of the clause (the clause keyword).
  SourceLocation StartLoc;

  /// Ending location of the clause.
  SourceLocation EndLoc;

  /// Kind of the clause.
  OpenMPClauseKind Kind;

protected:
  OMPClause(OpenMPClauseKind K, SourceLocation StartLoc, SourceLocation EndLoc)
      : StartLoc(StartLoc), EndLoc(EndLoc), Kind(K) {}

public:
  /// Returns the starting location of the clause.
  SourceLocation getBeginLoc() const { return StartLoc; }

  /// Returns the ending location of the clause.
  SourceLocation getEndLoc() const { return EndLoc; }

  /// Sets the starting location of the clause.
  void setLocStart(SourceLocation Loc) { StartLoc = Loc; }

  /// Sets the ending location of the clause.
  void setLocEnd(SourceLocation Loc) { EndLoc = Loc; }

  /// Returns kind of OpenMP clause (private, shared, reduction, etc.).
  OpenMPClauseKind getClauseKind() const { return Kind; }

  bool isImplicit() const { return StartLoc.isInvalid(); }

  using child_iterator = StmtIterator;
  using const_child_iterator = ConstStmtIterator;
  using child_range = llvm::iterator_range<child_iterator>;
  using const_child_range = llvm::iterator_range<const_child_iterator>;

  child_range children();
  const_child_range children() const {
    auto Children = const_cast<OMPClause *>(this)->children();
    return const_child_range(Children.begin(), Children.end());
  }

  static bool classof(const OMPClause *) { return true; }
};

/// Class that handles pre-initialization statement for some clauses, like
/// 'shedule', 'firstprivate' etc.
class OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Pre-initialization statement for the clause.
  Stmt *PreInit = nullptr;

  /// Region that captures the associated stmt.
  OpenMPDirectiveKind CaptureRegion = OMPD_unknown;

protected:
  OMPClauseWithPreInit(const OMPClause *This) {
    assert(get(This) && "get is not tuned for pre-init.");
  }

  /// Set pre-initialization statement for the clause.
  void setPreInitStmt(Stmt *S, OpenMPDirectiveKind ThisRegion = OMPD_unknown) {
    PreInit = S;
    CaptureRegion = ThisRegion;
  }

public:
  /// Get pre-initialization statement for the clause.
  const Stmt *getPreInitStmt() const { return PreInit; }

  /// Get pre-initialization statement for the clause.
  Stmt *getPreInitStmt() { return PreInit; }

  /// Get capture region for the stmt in the clause.
  OpenMPDirectiveKind getCaptureRegion() const { return CaptureRegion; }

  static OMPClauseWithPreInit *get(OMPClause *C);
  static const OMPClauseWithPreInit *get(const OMPClause *C);
};

/// Class that handles post-update expression for some clauses, like
/// 'lastprivate', 'reduction' etc.
class OMPClauseWithPostUpdate : public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Post-update expression for the clause.
  Expr *PostUpdate = nullptr;

protected:
  OMPClauseWithPostUpdate(const OMPClause *This) : OMPClauseWithPreInit(This) {
    assert(get(This) && "get is not tuned for post-update.");
  }

  /// Set pre-initialization statement for the clause.
  void setPostUpdateExpr(Expr *S) { PostUpdate = S; }

public:
  /// Get post-update expression for the clause.
  const Expr *getPostUpdateExpr() const { return PostUpdate; }

  /// Get post-update expression for the clause.
  Expr *getPostUpdateExpr() { return PostUpdate; }

  static OMPClauseWithPostUpdate *get(OMPClause *C);
  static const OMPClauseWithPostUpdate *get(const OMPClause *C);
};

/// This represents clauses with the list of variables like 'private',
/// 'firstprivate', 'copyin', 'shared', or 'reduction' clauses in the
/// '#pragma omp ...' directives.
template <class T> class OMPVarListClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Number of variables in the list.
  unsigned NumVars;

protected:
  /// Build a clause with \a N variables
  ///
  /// \param K Kind of the clause.
  /// \param StartLoc Starting location of the clause (the clause keyword).
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPVarListClause(OpenMPClauseKind K, SourceLocation StartLoc,
                   SourceLocation LParenLoc, SourceLocation EndLoc, unsigned N)
      : OMPClause(K, StartLoc, EndLoc), LParenLoc(LParenLoc), NumVars(N) {}

  /// Fetches list of variables associated with this clause.
  MutableArrayRef<Expr *> getVarRefs() {
    return MutableArrayRef<Expr *>(
        static_cast<T *>(this)->template getTrailingObjects<Expr *>(), NumVars);
  }

  /// Sets the list of variables for this clause.
  void setVarRefs(ArrayRef<Expr *> VL) {
    assert(VL.size() == NumVars &&
           "Number of variables is not the same as the preallocated buffer");
    std::copy(VL.begin(), VL.end(),
              static_cast<T *>(this)->template getTrailingObjects<Expr *>());
  }

public:
  using varlist_iterator = MutableArrayRef<Expr *>::iterator;
  using varlist_const_iterator = ArrayRef<const Expr *>::iterator;
  using varlist_range = llvm::iterator_range<varlist_iterator>;
  using varlist_const_range = llvm::iterator_range<varlist_const_iterator>;

  unsigned varlist_size() const { return NumVars; }
  bool varlist_empty() const { return NumVars == 0; }

  varlist_range varlists() {
    return varlist_range(varlist_begin(), varlist_end());
  }
  varlist_const_range varlists() const {
    return varlist_const_range(varlist_begin(), varlist_end());
  }

  varlist_iterator varlist_begin() { return getVarRefs().begin(); }
  varlist_iterator varlist_end() { return getVarRefs().end(); }
  varlist_const_iterator varlist_begin() const { return getVarRefs().begin(); }
  varlist_const_iterator varlist_end() const { return getVarRefs().end(); }

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Fetches list of all variables in the clause.
  ArrayRef<const Expr *> getVarRefs() const {
    return llvm::makeArrayRef(
        static_cast<const T *>(this)->template getTrailingObjects<Expr *>(),
        NumVars);
  }
};

/// This represents 'if' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp parallel if(parallel:a > 5)
/// \endcode
/// In this example directive '#pragma omp parallel' has simple 'if' clause with
/// condition 'a > 5' and directive name modifier 'parallel'.
class OMPIfClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Condition of the 'if' clause.
  Stmt *Condition = nullptr;

  /// Location of ':' (if any).
  SourceLocation ColonLoc;

  /// Directive name modifier for the clause.
  OpenMPDirectiveKind NameModifier = OMPD_unknown;

  /// Name modifier location.
  SourceLocation NameModifierLoc;

  /// Set condition.
  void setCondition(Expr *Cond) { Condition = Cond; }

  /// Set directive name modifier for the clause.
  void setNameModifier(OpenMPDirectiveKind NM) { NameModifier = NM; }

  /// Set location of directive name modifier for the clause.
  void setNameModifierLoc(SourceLocation Loc) { NameModifierLoc = Loc; }

  /// Set location of ':'.
  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }

public:
  /// Build 'if' clause with condition \a Cond.
  ///
  /// \param NameModifier [OpenMP 4.1] Directive name modifier of clause.
  /// \param Cond Condition of the clause.
  /// \param HelperCond Helper condition for the clause.
  /// \param CaptureRegion Innermost OpenMP region where expressions in this
  /// clause must be captured.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param NameModifierLoc Location of directive name modifier.
  /// \param ColonLoc [OpenMP 4.1] Location of ':'.
  /// \param EndLoc Ending location of the clause.
  OMPIfClause(OpenMPDirectiveKind NameModifier, Expr *Cond, Stmt *HelperCond,
              OpenMPDirectiveKind CaptureRegion, SourceLocation StartLoc,
              SourceLocation LParenLoc, SourceLocation NameModifierLoc,
              SourceLocation ColonLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_if, StartLoc, EndLoc), OMPClauseWithPreInit(this),
        LParenLoc(LParenLoc), Condition(Cond), ColonLoc(ColonLoc),
        NameModifier(NameModifier), NameModifierLoc(NameModifierLoc) {
    setPreInitStmt(HelperCond, CaptureRegion);
  }

  /// Build an empty clause.
  OMPIfClause()
      : OMPClause(OMPC_if, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return the location of ':'.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Returns condition.
  Expr *getCondition() const { return cast_or_null<Expr>(Condition); }

  /// Return directive name modifier associated with the clause.
  OpenMPDirectiveKind getNameModifier() const { return NameModifier; }

  /// Return the location of directive name modifier.
  SourceLocation getNameModifierLoc() const { return NameModifierLoc; }

  child_range children() { return child_range(&Condition, &Condition + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_if;
  }
};

/// This represents 'final' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp task final(a > 5)
/// \endcode
/// In this example directive '#pragma omp task' has simple 'final'
/// clause with condition 'a > 5'.
class OMPFinalClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Condition of the 'if' clause.
  Stmt *Condition = nullptr;

  /// Set condition.
  void setCondition(Expr *Cond) { Condition = Cond; }

public:
  /// Build 'final' clause with condition \a Cond.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param Cond Condition of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPFinalClause(Expr *Cond, SourceLocation StartLoc, SourceLocation LParenLoc,
                 SourceLocation EndLoc)
      : OMPClause(OMPC_final, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Condition(Cond) {}

  /// Build an empty clause.
  OMPFinalClause()
      : OMPClause(OMPC_final, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Returns condition.
  Expr *getCondition() const { return cast_or_null<Expr>(Condition); }

  child_range children() { return child_range(&Condition, &Condition + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_final;
  }
};

/// This represents 'num_threads' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp parallel num_threads(6)
/// \endcode
/// In this example directive '#pragma omp parallel' has simple 'num_threads'
/// clause with number of threads '6'.
class OMPNumThreadsClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Condition of the 'num_threads' clause.
  Stmt *NumThreads = nullptr;

  /// Set condition.
  void setNumThreads(Expr *NThreads) { NumThreads = NThreads; }

public:
  /// Build 'num_threads' clause with condition \a NumThreads.
  ///
  /// \param NumThreads Number of threads for the construct.
  /// \param HelperNumThreads Helper Number of threads for the construct.
  /// \param CaptureRegion Innermost OpenMP region where expressions in this
  /// clause must be captured.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPNumThreadsClause(Expr *NumThreads, Stmt *HelperNumThreads,
                      OpenMPDirectiveKind CaptureRegion,
                      SourceLocation StartLoc, SourceLocation LParenLoc,
                      SourceLocation EndLoc)
      : OMPClause(OMPC_num_threads, StartLoc, EndLoc),
        OMPClauseWithPreInit(this), LParenLoc(LParenLoc),
        NumThreads(NumThreads) {
    setPreInitStmt(HelperNumThreads, CaptureRegion);
  }

  /// Build an empty clause.
  OMPNumThreadsClause()
      : OMPClause(OMPC_num_threads, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Returns number of threads.
  Expr *getNumThreads() const { return cast_or_null<Expr>(NumThreads); }

  child_range children() { return child_range(&NumThreads, &NumThreads + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_num_threads;
  }
};

/// This represents 'safelen' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp simd safelen(4)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'safelen'
/// with single expression '4'.
/// If the safelen clause is used then no two iterations executed
/// concurrently with SIMD instructions can have a greater distance
/// in the logical iteration space than its value. The parameter of
/// the safelen clause must be a constant positive integer expression.
class OMPSafelenClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Safe iteration space distance.
  Stmt *Safelen = nullptr;

  /// Set safelen.
  void setSafelen(Expr *Len) { Safelen = Len; }

public:
  /// Build 'safelen' clause.
  ///
  /// \param Len Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPSafelenClause(Expr *Len, SourceLocation StartLoc, SourceLocation LParenLoc,
                   SourceLocation EndLoc)
      : OMPClause(OMPC_safelen, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Safelen(Len) {}

  /// Build an empty clause.
  explicit OMPSafelenClause()
      : OMPClause(OMPC_safelen, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return safe iteration space distance.
  Expr *getSafelen() const { return cast_or_null<Expr>(Safelen); }

  child_range children() { return child_range(&Safelen, &Safelen + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_safelen;
  }
};

/// This represents 'simdlen' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp simd simdlen(4)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'simdlen'
/// with single expression '4'.
/// If the 'simdlen' clause is used then it specifies the preferred number of
/// iterations to be executed concurrently. The parameter of the 'simdlen'
/// clause must be a constant positive integer expression.
class OMPSimdlenClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Safe iteration space distance.
  Stmt *Simdlen = nullptr;

  /// Set simdlen.
  void setSimdlen(Expr *Len) { Simdlen = Len; }

public:
  /// Build 'simdlen' clause.
  ///
  /// \param Len Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPSimdlenClause(Expr *Len, SourceLocation StartLoc, SourceLocation LParenLoc,
                   SourceLocation EndLoc)
      : OMPClause(OMPC_simdlen, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Simdlen(Len) {}

  /// Build an empty clause.
  explicit OMPSimdlenClause()
      : OMPClause(OMPC_simdlen, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return safe iteration space distance.
  Expr *getSimdlen() const { return cast_or_null<Expr>(Simdlen); }

  child_range children() { return child_range(&Simdlen, &Simdlen + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_simdlen;
  }
};

/// This represents 'collapse' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp simd collapse(3)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'collapse'
/// with single expression '3'.
/// The parameter must be a constant positive integer expression, it specifies
/// the number of nested loops that should be collapsed into a single iteration
/// space.
class OMPCollapseClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Number of for-loops.
  Stmt *NumForLoops = nullptr;

  /// Set the number of associated for-loops.
  void setNumForLoops(Expr *Num) { NumForLoops = Num; }

public:
  /// Build 'collapse' clause.
  ///
  /// \param Num Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPCollapseClause(Expr *Num, SourceLocation StartLoc,
                    SourceLocation LParenLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_collapse, StartLoc, EndLoc), LParenLoc(LParenLoc),
        NumForLoops(Num) {}

  /// Build an empty clause.
  explicit OMPCollapseClause()
      : OMPClause(OMPC_collapse, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return the number of associated for-loops.
  Expr *getNumForLoops() const { return cast_or_null<Expr>(NumForLoops); }

  child_range children() { return child_range(&NumForLoops, &NumForLoops + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_collapse;
  }
};

/// This represents 'default' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp parallel default(shared)
/// \endcode
/// In this example directive '#pragma omp parallel' has simple 'default'
/// clause with kind 'shared'.
class OMPDefaultClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// A kind of the 'default' clause.
  OpenMPDefaultClauseKind Kind = OMPC_DEFAULT_unknown;

  /// Start location of the kind in source code.
  SourceLocation KindKwLoc;

  /// Set kind of the clauses.
  ///
  /// \param K Argument of clause.
  void setDefaultKind(OpenMPDefaultClauseKind K) { Kind = K; }

  /// Set argument location.
  ///
  /// \param KLoc Argument location.
  void setDefaultKindKwLoc(SourceLocation KLoc) { KindKwLoc = KLoc; }

public:
  /// Build 'default' clause with argument \a A ('none' or 'shared').
  ///
  /// \param A Argument of the clause ('none' or 'shared').
  /// \param ALoc Starting location of the argument.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPDefaultClause(OpenMPDefaultClauseKind A, SourceLocation ALoc,
                   SourceLocation StartLoc, SourceLocation LParenLoc,
                   SourceLocation EndLoc)
      : OMPClause(OMPC_default, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Kind(A), KindKwLoc(ALoc) {}

  /// Build an empty clause.
  OMPDefaultClause()
      : OMPClause(OMPC_default, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Returns kind of the clause.
  OpenMPDefaultClauseKind getDefaultKind() const { return Kind; }

  /// Returns location of clause kind.
  SourceLocation getDefaultKindKwLoc() const { return KindKwLoc; }

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_default;
  }
};

/// This represents 'proc_bind' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp parallel proc_bind(master)
/// \endcode
/// In this example directive '#pragma omp parallel' has simple 'proc_bind'
/// clause with kind 'master'.
class OMPProcBindClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// A kind of the 'proc_bind' clause.
  OpenMPProcBindClauseKind Kind = OMPC_PROC_BIND_unknown;

  /// Start location of the kind in source code.
  SourceLocation KindKwLoc;

  /// Set kind of the clause.
  ///
  /// \param K Kind of clause.
  void setProcBindKind(OpenMPProcBindClauseKind K) { Kind = K; }

  /// Set clause kind location.
  ///
  /// \param KLoc Kind location.
  void setProcBindKindKwLoc(SourceLocation KLoc) { KindKwLoc = KLoc; }

public:
  /// Build 'proc_bind' clause with argument \a A ('master', 'close' or
  ///        'spread').
  ///
  /// \param A Argument of the clause ('master', 'close' or 'spread').
  /// \param ALoc Starting location of the argument.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPProcBindClause(OpenMPProcBindClauseKind A, SourceLocation ALoc,
                    SourceLocation StartLoc, SourceLocation LParenLoc,
                    SourceLocation EndLoc)
      : OMPClause(OMPC_proc_bind, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Kind(A), KindKwLoc(ALoc) {}

  /// Build an empty clause.
  OMPProcBindClause()
      : OMPClause(OMPC_proc_bind, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Returns kind of the clause.
  OpenMPProcBindClauseKind getProcBindKind() const { return Kind; }

  /// Returns location of clause kind.
  SourceLocation getProcBindKindKwLoc() const { return KindKwLoc; }

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_proc_bind;
  }
};

/// This represents 'unified_address' clause in the '#pragma omp requires'
/// directive.
///
/// \code
/// #pragma omp requires unified_address
/// \endcode
/// In this example directive '#pragma omp requires' has 'unified_address'
/// clause.
class OMPUnifiedAddressClause final : public OMPClause {
public:
  friend class OMPClauseReader;
  /// Build 'unified_address' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPUnifiedAddressClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_unified_address, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPUnifiedAddressClause()
      : OMPClause(OMPC_unified_address, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_unified_address;
  }
};

/// This represents 'unified_shared_memory' clause in the '#pragma omp requires'
/// directive.
///
/// \code
/// #pragma omp requires unified_shared_memory
/// \endcode
/// In this example directive '#pragma omp requires' has 'unified_shared_memory'
/// clause.
class OMPUnifiedSharedMemoryClause final : public OMPClause {
public:
  friend class OMPClauseReader;
  /// Build 'unified_shared_memory' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPUnifiedSharedMemoryClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_unified_shared_memory, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPUnifiedSharedMemoryClause()
      : OMPClause(OMPC_unified_shared_memory, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_unified_shared_memory;
  }
};

/// This represents 'reverse_offload' clause in the '#pragma omp requires'
/// directive.
///
/// \code
/// #pragma omp requires reverse_offload
/// \endcode
/// In this example directive '#pragma omp requires' has 'reverse_offload'
/// clause.
class OMPReverseOffloadClause final : public OMPClause {
public:
  friend class OMPClauseReader;
  /// Build 'reverse_offload' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPReverseOffloadClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_reverse_offload, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPReverseOffloadClause()
      : OMPClause(OMPC_reverse_offload, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_reverse_offload;
  }
};

/// This represents 'dynamic_allocators' clause in the '#pragma omp requires'
/// directive.
///
/// \code
/// #pragma omp requires dynamic_allocators
/// \endcode
/// In this example directive '#pragma omp requires' has 'dynamic_allocators'
/// clause.
class OMPDynamicAllocatorsClause final : public OMPClause {
public:
  friend class OMPClauseReader;
  /// Build 'dynamic_allocators' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPDynamicAllocatorsClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_dynamic_allocators, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPDynamicAllocatorsClause()
      : OMPClause(OMPC_dynamic_allocators, SourceLocation(), SourceLocation()) {
  }

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_dynamic_allocators;
  }
};

/// This represents 'schedule' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp for schedule(static, 3)
/// \endcode
/// In this example directive '#pragma omp for' has 'schedule' clause with
/// arguments 'static' and '3'.
class OMPScheduleClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// A kind of the 'schedule' clause.
  OpenMPScheduleClauseKind Kind = OMPC_SCHEDULE_unknown;

  /// Modifiers for 'schedule' clause.
  enum {FIRST, SECOND, NUM_MODIFIERS};
  OpenMPScheduleClauseModifier Modifiers[NUM_MODIFIERS];

  /// Locations of modifiers.
  SourceLocation ModifiersLoc[NUM_MODIFIERS];

  /// Start location of the schedule ind in source code.
  SourceLocation KindLoc;

  /// Location of ',' (if any).
  SourceLocation CommaLoc;

  /// Chunk size.
  Expr *ChunkSize = nullptr;

  /// Set schedule kind.
  ///
  /// \param K Schedule kind.
  void setScheduleKind(OpenMPScheduleClauseKind K) { Kind = K; }

  /// Set the first schedule modifier.
  ///
  /// \param M Schedule modifier.
  void setFirstScheduleModifier(OpenMPScheduleClauseModifier M) {
    Modifiers[FIRST] = M;
  }

  /// Set the second schedule modifier.
  ///
  /// \param M Schedule modifier.
  void setSecondScheduleModifier(OpenMPScheduleClauseModifier M) {
    Modifiers[SECOND] = M;
  }

  /// Set location of the first schedule modifier.
  void setFirstScheduleModifierLoc(SourceLocation Loc) {
    ModifiersLoc[FIRST] = Loc;
  }

  /// Set location of the second schedule modifier.
  void setSecondScheduleModifierLoc(SourceLocation Loc) {
    ModifiersLoc[SECOND] = Loc;
  }

  /// Set schedule modifier location.
  ///
  /// \param M Schedule modifier location.
  void setScheduleModifer(OpenMPScheduleClauseModifier M) {
    if (Modifiers[FIRST] == OMPC_SCHEDULE_MODIFIER_unknown)
      Modifiers[FIRST] = M;
    else {
      assert(Modifiers[SECOND] == OMPC_SCHEDULE_MODIFIER_unknown);
      Modifiers[SECOND] = M;
    }
  }

  /// Sets the location of '('.
  ///
  /// \param Loc Location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Set schedule kind start location.
  ///
  /// \param KLoc Schedule kind location.
  void setScheduleKindLoc(SourceLocation KLoc) { KindLoc = KLoc; }

  /// Set location of ','.
  ///
  /// \param Loc Location of ','.
  void setCommaLoc(SourceLocation Loc) { CommaLoc = Loc; }

  /// Set chunk size.
  ///
  /// \param E Chunk size.
  void setChunkSize(Expr *E) { ChunkSize = E; }

public:
  /// Build 'schedule' clause with schedule kind \a Kind and chunk size
  /// expression \a ChunkSize.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param KLoc Starting location of the argument.
  /// \param CommaLoc Location of ','.
  /// \param EndLoc Ending location of the clause.
  /// \param Kind Schedule kind.
  /// \param ChunkSize Chunk size.
  /// \param HelperChunkSize Helper chunk size for combined directives.
  /// \param M1 The first modifier applied to 'schedule' clause.
  /// \param M1Loc Location of the first modifier
  /// \param M2 The second modifier applied to 'schedule' clause.
  /// \param M2Loc Location of the second modifier
  OMPScheduleClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                    SourceLocation KLoc, SourceLocation CommaLoc,
                    SourceLocation EndLoc, OpenMPScheduleClauseKind Kind,
                    Expr *ChunkSize, Stmt *HelperChunkSize,
                    OpenMPScheduleClauseModifier M1, SourceLocation M1Loc,
                    OpenMPScheduleClauseModifier M2, SourceLocation M2Loc)
      : OMPClause(OMPC_schedule, StartLoc, EndLoc), OMPClauseWithPreInit(this),
        LParenLoc(LParenLoc), Kind(Kind), KindLoc(KLoc), CommaLoc(CommaLoc),
        ChunkSize(ChunkSize) {
    setPreInitStmt(HelperChunkSize);
    Modifiers[FIRST] = M1;
    Modifiers[SECOND] = M2;
    ModifiersLoc[FIRST] = M1Loc;
    ModifiersLoc[SECOND] = M2Loc;
  }

  /// Build an empty clause.
  explicit OMPScheduleClause()
      : OMPClause(OMPC_schedule, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {
    Modifiers[FIRST] = OMPC_SCHEDULE_MODIFIER_unknown;
    Modifiers[SECOND] = OMPC_SCHEDULE_MODIFIER_unknown;
  }

  /// Get kind of the clause.
  OpenMPScheduleClauseKind getScheduleKind() const { return Kind; }

  /// Get the first modifier of the clause.
  OpenMPScheduleClauseModifier getFirstScheduleModifier() const {
    return Modifiers[FIRST];
  }

  /// Get the second modifier of the clause.
  OpenMPScheduleClauseModifier getSecondScheduleModifier() const {
    return Modifiers[SECOND];
  }

  /// Get location of '('.
  SourceLocation getLParenLoc() { return LParenLoc; }

  /// Get kind location.
  SourceLocation getScheduleKindLoc() { return KindLoc; }

  /// Get the first modifier location.
  SourceLocation getFirstScheduleModifierLoc() const {
    return ModifiersLoc[FIRST];
  }

  /// Get the second modifier location.
  SourceLocation getSecondScheduleModifierLoc() const {
    return ModifiersLoc[SECOND];
  }

  /// Get location of ','.
  SourceLocation getCommaLoc() { return CommaLoc; }

  /// Get chunk size.
  Expr *getChunkSize() { return ChunkSize; }

  /// Get chunk size.
  const Expr *getChunkSize() const { return ChunkSize; }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(&ChunkSize),
                       reinterpret_cast<Stmt **>(&ChunkSize) + 1);
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_schedule;
  }
};

/// This represents 'ordered' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp for ordered (2)
/// \endcode
/// In this example directive '#pragma omp for' has 'ordered' clause with
/// parameter 2.
class OMPOrderedClause final
    : public OMPClause,
      private llvm::TrailingObjects<OMPOrderedClause, Expr *> {
  friend class OMPClauseReader;
  friend TrailingObjects;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Number of for-loops.
  Stmt *NumForLoops = nullptr;

  /// Real number of loops.
  unsigned NumberOfLoops = 0;

  /// Build 'ordered' clause.
  ///
  /// \param Num Expression, possibly associated with this clause.
  /// \param NumLoops Number of loops, associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPOrderedClause(Expr *Num, unsigned NumLoops, SourceLocation StartLoc,
                   SourceLocation LParenLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_ordered, StartLoc, EndLoc), LParenLoc(LParenLoc),
        NumForLoops(Num), NumberOfLoops(NumLoops) {}

  /// Build an empty clause.
  explicit OMPOrderedClause(unsigned NumLoops)
      : OMPClause(OMPC_ordered, SourceLocation(), SourceLocation()),
        NumberOfLoops(NumLoops) {}

  /// Set the number of associated for-loops.
  void setNumForLoops(Expr *Num) { NumForLoops = Num; }

public:
  /// Build 'ordered' clause.
  ///
  /// \param Num Expression, possibly associated with this clause.
  /// \param NumLoops Number of loops, associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  static OMPOrderedClause *Create(const ASTContext &C, Expr *Num,
                                  unsigned NumLoops, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc);

  /// Build an empty clause.
  static OMPOrderedClause* CreateEmpty(const ASTContext &C, unsigned NumLoops);

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return the number of associated for-loops.
  Expr *getNumForLoops() const { return cast_or_null<Expr>(NumForLoops); }

  /// Set number of iterations for the specified loop.
  void setLoopNumIterations(unsigned NumLoop, Expr *NumIterations);
  /// Get number of iterations for all the loops.
  ArrayRef<Expr *> getLoopNumIterations() const;

  /// Set loop counter for the specified loop.
  void setLoopCounter(unsigned NumLoop, Expr *Counter);
  /// Get loops counter for the specified loop.
  Expr *getLoopCounter(unsigned NumLoop);
  const Expr *getLoopCounter(unsigned NumLoop) const;

  child_range children() { return child_range(&NumForLoops, &NumForLoops + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_ordered;
  }
};

/// This represents 'nowait' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp for nowait
/// \endcode
/// In this example directive '#pragma omp for' has 'nowait' clause.
class OMPNowaitClause : public OMPClause {
public:
  /// Build 'nowait' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPNowaitClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_nowait, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPNowaitClause()
      : OMPClause(OMPC_nowait, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_nowait;
  }
};

/// This represents 'untied' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp task untied
/// \endcode
/// In this example directive '#pragma omp task' has 'untied' clause.
class OMPUntiedClause : public OMPClause {
public:
  /// Build 'untied' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPUntiedClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_untied, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPUntiedClause()
      : OMPClause(OMPC_untied, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_untied;
  }
};

/// This represents 'mergeable' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp task mergeable
/// \endcode
/// In this example directive '#pragma omp task' has 'mergeable' clause.
class OMPMergeableClause : public OMPClause {
public:
  /// Build 'mergeable' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPMergeableClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_mergeable, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPMergeableClause()
      : OMPClause(OMPC_mergeable, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_mergeable;
  }
};

/// This represents 'read' clause in the '#pragma omp atomic' directive.
///
/// \code
/// #pragma omp atomic read
/// \endcode
/// In this example directive '#pragma omp atomic' has 'read' clause.
class OMPReadClause : public OMPClause {
public:
  /// Build 'read' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPReadClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_read, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPReadClause() : OMPClause(OMPC_read, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_read;
  }
};

/// This represents 'write' clause in the '#pragma omp atomic' directive.
///
/// \code
/// #pragma omp atomic write
/// \endcode
/// In this example directive '#pragma omp atomic' has 'write' clause.
class OMPWriteClause : public OMPClause {
public:
  /// Build 'write' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPWriteClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_write, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPWriteClause()
      : OMPClause(OMPC_write, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_write;
  }
};

/// This represents 'update' clause in the '#pragma omp atomic'
/// directive.
///
/// \code
/// #pragma omp atomic update
/// \endcode
/// In this example directive '#pragma omp atomic' has 'update' clause.
class OMPUpdateClause : public OMPClause {
public:
  /// Build 'update' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPUpdateClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_update, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPUpdateClause()
      : OMPClause(OMPC_update, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_update;
  }
};

/// This represents 'capture' clause in the '#pragma omp atomic'
/// directive.
///
/// \code
/// #pragma omp atomic capture
/// \endcode
/// In this example directive '#pragma omp atomic' has 'capture' clause.
class OMPCaptureClause : public OMPClause {
public:
  /// Build 'capture' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPCaptureClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_capture, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPCaptureClause()
      : OMPClause(OMPC_capture, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_capture;
  }
};

/// This represents 'seq_cst' clause in the '#pragma omp atomic'
/// directive.
///
/// \code
/// #pragma omp atomic seq_cst
/// \endcode
/// In this example directive '#pragma omp atomic' has 'seq_cst' clause.
class OMPSeqCstClause : public OMPClause {
public:
  /// Build 'seq_cst' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPSeqCstClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_seq_cst, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPSeqCstClause()
      : OMPClause(OMPC_seq_cst, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_seq_cst;
  }
};

/// This represents clause 'private' in the '#pragma omp ...' directives.
///
/// \code
/// #pragma omp parallel private(a,b)
/// \endcode
/// In this example directive '#pragma omp parallel' has clause 'private'
/// with the variables 'a' and 'b'.
class OMPPrivateClause final
    : public OMPVarListClause<OMPPrivateClause>,
      private llvm::TrailingObjects<OMPPrivateClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPPrivateClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                   SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPPrivateClause>(OMPC_private, StartLoc, LParenLoc,
                                           EndLoc, N) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPPrivateClause(unsigned N)
      : OMPVarListClause<OMPPrivateClause>(OMPC_private, SourceLocation(),
                                           SourceLocation(), SourceLocation(),
                                           N) {}

  /// Sets the list of references to private copies with initializers for
  /// new private variables.
  /// \param VL List of references.
  void setPrivateCopies(ArrayRef<Expr *> VL);

  /// Gets the list of references to private copies with initializers for
  /// new private variables.
  MutableArrayRef<Expr *> getPrivateCopies() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivateCopies() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param PrivateVL List of references to private copies with initializers.
  static OMPPrivateClause *Create(const ASTContext &C, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation EndLoc, ArrayRef<Expr *> VL,
                                  ArrayRef<Expr *> PrivateVL);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPPrivateClause *CreateEmpty(const ASTContext &C, unsigned N);

  using private_copies_iterator = MutableArrayRef<Expr *>::iterator;
  using private_copies_const_iterator = ArrayRef<const Expr *>::iterator;
  using private_copies_range = llvm::iterator_range<private_copies_iterator>;
  using private_copies_const_range =
      llvm::iterator_range<private_copies_const_iterator>;

  private_copies_range private_copies() {
    return private_copies_range(getPrivateCopies().begin(),
                                getPrivateCopies().end());
  }

  private_copies_const_range private_copies() const {
    return private_copies_const_range(getPrivateCopies().begin(),
                                      getPrivateCopies().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_private;
  }
};

/// This represents clause 'firstprivate' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp parallel firstprivate(a,b)
/// \endcode
/// In this example directive '#pragma omp parallel' has clause 'firstprivate'
/// with the variables 'a' and 'b'.
class OMPFirstprivateClause final
    : public OMPVarListClause<OMPFirstprivateClause>,
      public OMPClauseWithPreInit,
      private llvm::TrailingObjects<OMPFirstprivateClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPFirstprivateClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                        SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPFirstprivateClause>(OMPC_firstprivate, StartLoc,
                                                LParenLoc, EndLoc, N),
        OMPClauseWithPreInit(this) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPFirstprivateClause(unsigned N)
      : OMPVarListClause<OMPFirstprivateClause>(
            OMPC_firstprivate, SourceLocation(), SourceLocation(),
            SourceLocation(), N),
        OMPClauseWithPreInit(this) {}

  /// Sets the list of references to private copies with initializers for
  /// new private variables.
  /// \param VL List of references.
  void setPrivateCopies(ArrayRef<Expr *> VL);

  /// Gets the list of references to private copies with initializers for
  /// new private variables.
  MutableArrayRef<Expr *> getPrivateCopies() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivateCopies() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Sets the list of references to initializer variables for new
  /// private variables.
  /// \param VL List of references.
  void setInits(ArrayRef<Expr *> VL);

  /// Gets the list of references to initializer variables for new
  /// private variables.
  MutableArrayRef<Expr *> getInits() {
    return MutableArrayRef<Expr *>(getPrivateCopies().end(), varlist_size());
  }
  ArrayRef<const Expr *> getInits() const {
    return llvm::makeArrayRef(getPrivateCopies().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the original variables.
  /// \param PrivateVL List of references to private copies with initializers.
  /// \param InitVL List of references to auto generated variables used for
  /// initialization of a single array element. Used if firstprivate variable is
  /// of array type.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  static OMPFirstprivateClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> VL, ArrayRef<Expr *> PrivateVL,
         ArrayRef<Expr *> InitVL, Stmt *PreInit);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPFirstprivateClause *CreateEmpty(const ASTContext &C, unsigned N);

  using private_copies_iterator = MutableArrayRef<Expr *>::iterator;
  using private_copies_const_iterator = ArrayRef<const Expr *>::iterator;
  using private_copies_range = llvm::iterator_range<private_copies_iterator>;
  using private_copies_const_range =
      llvm::iterator_range<private_copies_const_iterator>;

  private_copies_range private_copies() {
    return private_copies_range(getPrivateCopies().begin(),
                                getPrivateCopies().end());
  }
  private_copies_const_range private_copies() const {
    return private_copies_const_range(getPrivateCopies().begin(),
                                      getPrivateCopies().end());
  }

  using inits_iterator = MutableArrayRef<Expr *>::iterator;
  using inits_const_iterator = ArrayRef<const Expr *>::iterator;
  using inits_range = llvm::iterator_range<inits_iterator>;
  using inits_const_range = llvm::iterator_range<inits_const_iterator>;

  inits_range inits() {
    return inits_range(getInits().begin(), getInits().end());
  }
  inits_const_range inits() const {
    return inits_const_range(getInits().begin(), getInits().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_firstprivate;
  }
};

/// This represents clause 'lastprivate' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp simd lastprivate(a,b)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'lastprivate'
/// with the variables 'a' and 'b'.
class OMPLastprivateClause final
    : public OMPVarListClause<OMPLastprivateClause>,
      public OMPClauseWithPostUpdate,
      private llvm::TrailingObjects<OMPLastprivateClause, Expr *> {
  // There are 4 additional tail-allocated arrays at the end of the class:
  // 1. Contains list of pseudo variables with the default initialization for
  // each non-firstprivate variables. Used in codegen for initialization of
  // lastprivate copies.
  // 2. List of helper expressions for proper generation of assignment operation
  // required for lastprivate clause. This list represents private variables
  // (for arrays, single array element).
  // 3. List of helper expressions for proper generation of assignment operation
  // required for lastprivate clause. This list represents original variables
  // (for arrays, single array element).
  // 4. List of helper expressions that represents assignment operation:
  // \code
  // DstExprs = SrcExprs;
  // \endcode
  // Required for proper codegen of final assignment performed by the
  // lastprivate clause.
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPLastprivateClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                       SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPLastprivateClause>(OMPC_lastprivate, StartLoc,
                                               LParenLoc, EndLoc, N),
        OMPClauseWithPostUpdate(this) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPLastprivateClause(unsigned N)
      : OMPVarListClause<OMPLastprivateClause>(
            OMPC_lastprivate, SourceLocation(), SourceLocation(),
            SourceLocation(), N),
        OMPClauseWithPostUpdate(this) {}

  /// Get the list of helper expressions for initialization of private
  /// copies for lastprivate variables.
  MutableArrayRef<Expr *> getPrivateCopies() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivateCopies() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent private variables (for arrays, single
  /// array element) in the final assignment statement performed by the
  /// lastprivate clause.
  void setSourceExprs(ArrayRef<Expr *> SrcExprs);

  /// Get the list of helper source expressions.
  MutableArrayRef<Expr *> getSourceExprs() {
    return MutableArrayRef<Expr *>(getPrivateCopies().end(), varlist_size());
  }
  ArrayRef<const Expr *> getSourceExprs() const {
    return llvm::makeArrayRef(getPrivateCopies().end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent original variables (for arrays, single
  /// array element) in the final assignment statement performed by the
  /// lastprivate clause.
  void setDestinationExprs(ArrayRef<Expr *> DstExprs);

  /// Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getDestinationExprs() {
    return MutableArrayRef<Expr *>(getSourceExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getDestinationExprs() const {
    return llvm::makeArrayRef(getSourceExprs().end(), varlist_size());
  }

  /// Set list of helper assignment expressions, required for proper
  /// codegen of the clause. These expressions are assignment expressions that
  /// assign private copy of the variable to original variable.
  void setAssignmentOps(ArrayRef<Expr *> AssignmentOps);

  /// Get the list of helper assignment expressions.
  MutableArrayRef<Expr *> getAssignmentOps() {
    return MutableArrayRef<Expr *>(getDestinationExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getAssignmentOps() const {
    return llvm::makeArrayRef(getDestinationExprs().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param SrcExprs List of helper expressions for proper generation of
  /// assignment operation required for lastprivate clause. This list represents
  /// private variables (for arrays, single array element).
  /// \param DstExprs List of helper expressions for proper generation of
  /// assignment operation required for lastprivate clause. This list represents
  /// original variables (for arrays, single array element).
  /// \param AssignmentOps List of helper expressions that represents assignment
  /// operation:
  /// \code
  /// DstExprs = SrcExprs;
  /// \endcode
  /// Required for proper codegen of final assignment performed by the
  /// lastprivate clause.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  /// \param PostUpdate Expression that must be executed after exit from the
  /// OpenMP region with this clause.
  static OMPLastprivateClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> VL, ArrayRef<Expr *> SrcExprs,
         ArrayRef<Expr *> DstExprs, ArrayRef<Expr *> AssignmentOps,
         Stmt *PreInit, Expr *PostUpdate);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPLastprivateClause *CreateEmpty(const ASTContext &C, unsigned N);

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  /// Set list of helper expressions, required for generation of private
  /// copies of original lastprivate variables.
  void setPrivateCopies(ArrayRef<Expr *> PrivateCopies);

  helper_expr_const_range private_copies() const {
    return helper_expr_const_range(getPrivateCopies().begin(),
                                   getPrivateCopies().end());
  }

  helper_expr_range private_copies() {
    return helper_expr_range(getPrivateCopies().begin(),
                             getPrivateCopies().end());
  }

  helper_expr_const_range source_exprs() const {
    return helper_expr_const_range(getSourceExprs().begin(),
                                   getSourceExprs().end());
  }

  helper_expr_range source_exprs() {
    return helper_expr_range(getSourceExprs().begin(), getSourceExprs().end());
  }

  helper_expr_const_range destination_exprs() const {
    return helper_expr_const_range(getDestinationExprs().begin(),
                                   getDestinationExprs().end());
  }

  helper_expr_range destination_exprs() {
    return helper_expr_range(getDestinationExprs().begin(),
                             getDestinationExprs().end());
  }

  helper_expr_const_range assignment_ops() const {
    return helper_expr_const_range(getAssignmentOps().begin(),
                                   getAssignmentOps().end());
  }

  helper_expr_range assignment_ops() {
    return helper_expr_range(getAssignmentOps().begin(),
                             getAssignmentOps().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_lastprivate;
  }
};

/// This represents clause 'shared' in the '#pragma omp ...' directives.
///
/// \code
/// #pragma omp parallel shared(a,b)
/// \endcode
/// In this example directive '#pragma omp parallel' has clause 'shared'
/// with the variables 'a' and 'b'.
class OMPSharedClause final
    : public OMPVarListClause<OMPSharedClause>,
      private llvm::TrailingObjects<OMPSharedClause, Expr *> {
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPSharedClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                  SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPSharedClause>(OMPC_shared, StartLoc, LParenLoc,
                                          EndLoc, N) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPSharedClause(unsigned N)
      : OMPVarListClause<OMPSharedClause>(OMPC_shared, SourceLocation(),
                                          SourceLocation(), SourceLocation(),
                                          N) {}

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  static OMPSharedClause *Create(const ASTContext &C, SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc, ArrayRef<Expr *> VL);

  /// Creates an empty clause with \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPSharedClause *CreateEmpty(const ASTContext &C, unsigned N);

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_shared;
  }
};

/// This represents clause 'reduction' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp parallel reduction(+:a,b)
/// \endcode
/// In this example directive '#pragma omp parallel' has clause 'reduction'
/// with operator '+' and the variables 'a' and 'b'.
class OMPReductionClause final
    : public OMPVarListClause<OMPReductionClause>,
      public OMPClauseWithPostUpdate,
      private llvm::TrailingObjects<OMPReductionClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Location of ':'.
  SourceLocation ColonLoc;

  /// Nested name specifier for C++.
  NestedNameSpecifierLoc QualifierLoc;

  /// Name of custom operator.
  DeclarationNameInfo NameInfo;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param ColonLoc Location of ':'.
  /// \param N Number of the variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  OMPReductionClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                     SourceLocation ColonLoc, SourceLocation EndLoc, unsigned N,
                     NestedNameSpecifierLoc QualifierLoc,
                     const DeclarationNameInfo &NameInfo)
      : OMPVarListClause<OMPReductionClause>(OMPC_reduction, StartLoc,
                                             LParenLoc, EndLoc, N),
        OMPClauseWithPostUpdate(this), ColonLoc(ColonLoc),
        QualifierLoc(QualifierLoc), NameInfo(NameInfo) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPReductionClause(unsigned N)
      : OMPVarListClause<OMPReductionClause>(OMPC_reduction, SourceLocation(),
                                             SourceLocation(), SourceLocation(),
                                             N),
        OMPClauseWithPostUpdate(this) {}

  /// Sets location of ':' symbol in clause.
  void setColonLoc(SourceLocation CL) { ColonLoc = CL; }

  /// Sets the name info for specified reduction identifier.
  void setNameInfo(DeclarationNameInfo DNI) { NameInfo = DNI; }

  /// Sets the nested name specifier.
  void setQualifierLoc(NestedNameSpecifierLoc NSL) { QualifierLoc = NSL; }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent private copy of the reduction
  /// variable.
  void setPrivates(ArrayRef<Expr *> Privates);

  /// Get the list of helper privates.
  MutableArrayRef<Expr *> getPrivates() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivates() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent LHS expression in the final
  /// reduction expression performed by the reduction clause.
  void setLHSExprs(ArrayRef<Expr *> LHSExprs);

  /// Get the list of helper LHS expressions.
  MutableArrayRef<Expr *> getLHSExprs() {
    return MutableArrayRef<Expr *>(getPrivates().end(), varlist_size());
  }
  ArrayRef<const Expr *> getLHSExprs() const {
    return llvm::makeArrayRef(getPrivates().end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent RHS expression in the final
  /// reduction expression performed by the reduction clause.
  /// Also, variables in these expressions are used for proper initialization of
  /// reduction copies.
  void setRHSExprs(ArrayRef<Expr *> RHSExprs);

  /// Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getRHSExprs() {
    return MutableArrayRef<Expr *>(getLHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getRHSExprs() const {
    return llvm::makeArrayRef(getLHSExprs().end(), varlist_size());
  }

  /// Set list of helper reduction expressions, required for proper
  /// codegen of the clause. These expressions are binary expressions or
  /// operator/custom reduction call that calculates new value from source
  /// helper expressions to destination helper expressions.
  void setReductionOps(ArrayRef<Expr *> ReductionOps);

  /// Get the list of helper reduction expressions.
  MutableArrayRef<Expr *> getReductionOps() {
    return MutableArrayRef<Expr *>(getRHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getReductionOps() const {
    return llvm::makeArrayRef(getRHSExprs().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param VL The variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  /// \param Privates List of helper expressions for proper generation of
  /// private copies.
  /// \param LHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// LHSs of the reduction expressions.
  /// \param RHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// RHSs of the reduction expressions.
  /// Also, variables in these expressions are used for proper initialization of
  /// reduction copies.
  /// \param ReductionOps List of helper expressions that represents reduction
  /// expressions:
  /// \code
  /// LHSExprs binop RHSExprs;
  /// operator binop(LHSExpr, RHSExpr);
  /// <CutomReduction>(LHSExpr, RHSExpr);
  /// \endcode
  /// Required for proper codegen of final reduction operation performed by the
  /// reduction clause.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  /// \param PostUpdate Expression that must be executed after exit from the
  /// OpenMP region with this clause.
  static OMPReductionClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef<Expr *> VL,
         NestedNameSpecifierLoc QualifierLoc,
         const DeclarationNameInfo &NameInfo, ArrayRef<Expr *> Privates,
         ArrayRef<Expr *> LHSExprs, ArrayRef<Expr *> RHSExprs,
         ArrayRef<Expr *> ReductionOps, Stmt *PreInit, Expr *PostUpdate);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPReductionClause *CreateEmpty(const ASTContext &C, unsigned N);

  /// Gets location of ':' symbol in clause.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Gets the name info for specified reduction identifier.
  const DeclarationNameInfo &getNameInfo() const { return NameInfo; }

  /// Gets the nested name specifier.
  NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  helper_expr_const_range privates() const {
    return helper_expr_const_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_range privates() {
    return helper_expr_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_const_range lhs_exprs() const {
    return helper_expr_const_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_range lhs_exprs() {
    return helper_expr_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_const_range rhs_exprs() const {
    return helper_expr_const_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_range rhs_exprs() {
    return helper_expr_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_const_range reduction_ops() const {
    return helper_expr_const_range(getReductionOps().begin(),
                                   getReductionOps().end());
  }

  helper_expr_range reduction_ops() {
    return helper_expr_range(getReductionOps().begin(),
                             getReductionOps().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_reduction;
  }
};

/// This represents clause 'task_reduction' in the '#pragma omp taskgroup'
/// directives.
///
/// \code
/// #pragma omp taskgroup task_reduction(+:a,b)
/// \endcode
/// In this example directive '#pragma omp taskgroup' has clause
/// 'task_reduction' with operator '+' and the variables 'a' and 'b'.
class OMPTaskReductionClause final
    : public OMPVarListClause<OMPTaskReductionClause>,
      public OMPClauseWithPostUpdate,
      private llvm::TrailingObjects<OMPTaskReductionClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Location of ':'.
  SourceLocation ColonLoc;

  /// Nested name specifier for C++.
  NestedNameSpecifierLoc QualifierLoc;

  /// Name of custom operator.
  DeclarationNameInfo NameInfo;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param ColonLoc Location of ':'.
  /// \param N Number of the variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  OMPTaskReductionClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                         SourceLocation ColonLoc, SourceLocation EndLoc,
                         unsigned N, NestedNameSpecifierLoc QualifierLoc,
                         const DeclarationNameInfo &NameInfo)
      : OMPVarListClause<OMPTaskReductionClause>(OMPC_task_reduction, StartLoc,
                                                 LParenLoc, EndLoc, N),
        OMPClauseWithPostUpdate(this), ColonLoc(ColonLoc),
        QualifierLoc(QualifierLoc), NameInfo(NameInfo) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPTaskReductionClause(unsigned N)
      : OMPVarListClause<OMPTaskReductionClause>(
            OMPC_task_reduction, SourceLocation(), SourceLocation(),
            SourceLocation(), N),
        OMPClauseWithPostUpdate(this) {}

  /// Sets location of ':' symbol in clause.
  void setColonLoc(SourceLocation CL) { ColonLoc = CL; }

  /// Sets the name info for specified reduction identifier.
  void setNameInfo(DeclarationNameInfo DNI) { NameInfo = DNI; }

  /// Sets the nested name specifier.
  void setQualifierLoc(NestedNameSpecifierLoc NSL) { QualifierLoc = NSL; }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent private copy of the reduction variable.
  void setPrivates(ArrayRef<Expr *> Privates);

  /// Get the list of helper privates.
  MutableArrayRef<Expr *> getPrivates() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivates() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent LHS expression in the final reduction
  /// expression performed by the reduction clause.
  void setLHSExprs(ArrayRef<Expr *> LHSExprs);

  /// Get the list of helper LHS expressions.
  MutableArrayRef<Expr *> getLHSExprs() {
    return MutableArrayRef<Expr *>(getPrivates().end(), varlist_size());
  }
  ArrayRef<const Expr *> getLHSExprs() const {
    return llvm::makeArrayRef(getPrivates().end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent RHS expression in the final reduction
  /// expression performed by the reduction clause. Also, variables in these
  /// expressions are used for proper initialization of reduction copies.
  void setRHSExprs(ArrayRef<Expr *> RHSExprs);

  ///  Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getRHSExprs() {
    return MutableArrayRef<Expr *>(getLHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getRHSExprs() const {
    return llvm::makeArrayRef(getLHSExprs().end(), varlist_size());
  }

  /// Set list of helper reduction expressions, required for proper
  /// codegen of the clause. These expressions are binary expressions or
  /// operator/custom reduction call that calculates new value from source
  /// helper expressions to destination helper expressions.
  void setReductionOps(ArrayRef<Expr *> ReductionOps);

  ///  Get the list of helper reduction expressions.
  MutableArrayRef<Expr *> getReductionOps() {
    return MutableArrayRef<Expr *>(getRHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getReductionOps() const {
    return llvm::makeArrayRef(getRHSExprs().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param VL The variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  /// \param Privates List of helper expressions for proper generation of
  /// private copies.
  /// \param LHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// LHSs of the reduction expressions.
  /// \param RHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// RHSs of the reduction expressions.
  /// Also, variables in these expressions are used for proper initialization of
  /// reduction copies.
  /// \param ReductionOps List of helper expressions that represents reduction
  /// expressions:
  /// \code
  /// LHSExprs binop RHSExprs;
  /// operator binop(LHSExpr, RHSExpr);
  /// <CutomReduction>(LHSExpr, RHSExpr);
  /// \endcode
  /// Required for proper codegen of final reduction operation performed by the
  /// reduction clause.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  /// \param PostUpdate Expression that must be executed after exit from the
  /// OpenMP region with this clause.
  static OMPTaskReductionClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef<Expr *> VL,
         NestedNameSpecifierLoc QualifierLoc,
         const DeclarationNameInfo &NameInfo, ArrayRef<Expr *> Privates,
         ArrayRef<Expr *> LHSExprs, ArrayRef<Expr *> RHSExprs,
         ArrayRef<Expr *> ReductionOps, Stmt *PreInit, Expr *PostUpdate);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPTaskReductionClause *CreateEmpty(const ASTContext &C, unsigned N);

  /// Gets location of ':' symbol in clause.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Gets the name info for specified reduction identifier.
  const DeclarationNameInfo &getNameInfo() const { return NameInfo; }

  /// Gets the nested name specifier.
  NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  helper_expr_const_range privates() const {
    return helper_expr_const_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_range privates() {
    return helper_expr_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_const_range lhs_exprs() const {
    return helper_expr_const_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_range lhs_exprs() {
    return helper_expr_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_const_range rhs_exprs() const {
    return helper_expr_const_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_range rhs_exprs() {
    return helper_expr_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_const_range reduction_ops() const {
    return helper_expr_const_range(getReductionOps().begin(),
                                   getReductionOps().end());
  }

  helper_expr_range reduction_ops() {
    return helper_expr_range(getReductionOps().begin(),
                             getReductionOps().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_task_reduction;
  }
};

/// This represents clause 'in_reduction' in the '#pragma omp task' directives.
///
/// \code
/// #pragma omp task in_reduction(+:a,b)
/// \endcode
/// In this example directive '#pragma omp task' has clause 'in_reduction' with
/// operator '+' and the variables 'a' and 'b'.
class OMPInReductionClause final
    : public OMPVarListClause<OMPInReductionClause>,
      public OMPClauseWithPostUpdate,
      private llvm::TrailingObjects<OMPInReductionClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Location of ':'.
  SourceLocation ColonLoc;

  /// Nested name specifier for C++.
  NestedNameSpecifierLoc QualifierLoc;

  /// Name of custom operator.
  DeclarationNameInfo NameInfo;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param ColonLoc Location of ':'.
  /// \param N Number of the variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  OMPInReductionClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                       SourceLocation ColonLoc, SourceLocation EndLoc,
                       unsigned N, NestedNameSpecifierLoc QualifierLoc,
                       const DeclarationNameInfo &NameInfo)
      : OMPVarListClause<OMPInReductionClause>(OMPC_in_reduction, StartLoc,
                                               LParenLoc, EndLoc, N),
        OMPClauseWithPostUpdate(this), ColonLoc(ColonLoc),
        QualifierLoc(QualifierLoc), NameInfo(NameInfo) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPInReductionClause(unsigned N)
      : OMPVarListClause<OMPInReductionClause>(
            OMPC_in_reduction, SourceLocation(), SourceLocation(),
            SourceLocation(), N),
        OMPClauseWithPostUpdate(this) {}

  /// Sets location of ':' symbol in clause.
  void setColonLoc(SourceLocation CL) { ColonLoc = CL; }

  /// Sets the name info for specified reduction identifier.
  void setNameInfo(DeclarationNameInfo DNI) { NameInfo = DNI; }

  /// Sets the nested name specifier.
  void setQualifierLoc(NestedNameSpecifierLoc NSL) { QualifierLoc = NSL; }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent private copy of the reduction variable.
  void setPrivates(ArrayRef<Expr *> Privates);

  /// Get the list of helper privates.
  MutableArrayRef<Expr *> getPrivates() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivates() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent LHS expression in the final reduction
  /// expression performed by the reduction clause.
  void setLHSExprs(ArrayRef<Expr *> LHSExprs);

  /// Get the list of helper LHS expressions.
  MutableArrayRef<Expr *> getLHSExprs() {
    return MutableArrayRef<Expr *>(getPrivates().end(), varlist_size());
  }
  ArrayRef<const Expr *> getLHSExprs() const {
    return llvm::makeArrayRef(getPrivates().end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the clause.
  /// These expressions represent RHS expression in the final reduction
  /// expression performed by the reduction clause. Also, variables in these
  /// expressions are used for proper initialization of reduction copies.
  void setRHSExprs(ArrayRef<Expr *> RHSExprs);

  ///  Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getRHSExprs() {
    return MutableArrayRef<Expr *>(getLHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getRHSExprs() const {
    return llvm::makeArrayRef(getLHSExprs().end(), varlist_size());
  }

  /// Set list of helper reduction expressions, required for proper
  /// codegen of the clause. These expressions are binary expressions or
  /// operator/custom reduction call that calculates new value from source
  /// helper expressions to destination helper expressions.
  void setReductionOps(ArrayRef<Expr *> ReductionOps);

  ///  Get the list of helper reduction expressions.
  MutableArrayRef<Expr *> getReductionOps() {
    return MutableArrayRef<Expr *>(getRHSExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getReductionOps() const {
    return llvm::makeArrayRef(getRHSExprs().end(), varlist_size());
  }

  /// Set list of helper reduction taskgroup descriptors.
  void setTaskgroupDescriptors(ArrayRef<Expr *> ReductionOps);

  ///  Get the list of helper reduction taskgroup descriptors.
  MutableArrayRef<Expr *> getTaskgroupDescriptors() {
    return MutableArrayRef<Expr *>(getReductionOps().end(), varlist_size());
  }
  ArrayRef<const Expr *> getTaskgroupDescriptors() const {
    return llvm::makeArrayRef(getReductionOps().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param VL The variables in the clause.
  /// \param QualifierLoc The nested-name qualifier with location information
  /// \param NameInfo The full name info for reduction identifier.
  /// \param Privates List of helper expressions for proper generation of
  /// private copies.
  /// \param LHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// LHSs of the reduction expressions.
  /// \param RHSExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// RHSs of the reduction expressions.
  /// Also, variables in these expressions are used for proper initialization of
  /// reduction copies.
  /// \param ReductionOps List of helper expressions that represents reduction
  /// expressions:
  /// \code
  /// LHSExprs binop RHSExprs;
  /// operator binop(LHSExpr, RHSExpr);
  /// <CutomReduction>(LHSExpr, RHSExpr);
  /// \endcode
  /// Required for proper codegen of final reduction operation performed by the
  /// reduction clause.
  /// \param TaskgroupDescriptors List of helper taskgroup descriptors for
  /// corresponding items in parent taskgroup task_reduction clause.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  /// \param PostUpdate Expression that must be executed after exit from the
  /// OpenMP region with this clause.
  static OMPInReductionClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef<Expr *> VL,
         NestedNameSpecifierLoc QualifierLoc,
         const DeclarationNameInfo &NameInfo, ArrayRef<Expr *> Privates,
         ArrayRef<Expr *> LHSExprs, ArrayRef<Expr *> RHSExprs,
         ArrayRef<Expr *> ReductionOps, ArrayRef<Expr *> TaskgroupDescriptors,
         Stmt *PreInit, Expr *PostUpdate);

  /// Creates an empty clause with the place for \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPInReductionClause *CreateEmpty(const ASTContext &C, unsigned N);

  /// Gets location of ':' symbol in clause.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Gets the name info for specified reduction identifier.
  const DeclarationNameInfo &getNameInfo() const { return NameInfo; }

  /// Gets the nested name specifier.
  NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  helper_expr_const_range privates() const {
    return helper_expr_const_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_range privates() {
    return helper_expr_range(getPrivates().begin(), getPrivates().end());
  }

  helper_expr_const_range lhs_exprs() const {
    return helper_expr_const_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_range lhs_exprs() {
    return helper_expr_range(getLHSExprs().begin(), getLHSExprs().end());
  }

  helper_expr_const_range rhs_exprs() const {
    return helper_expr_const_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_range rhs_exprs() {
    return helper_expr_range(getRHSExprs().begin(), getRHSExprs().end());
  }

  helper_expr_const_range reduction_ops() const {
    return helper_expr_const_range(getReductionOps().begin(),
                                   getReductionOps().end());
  }

  helper_expr_range reduction_ops() {
    return helper_expr_range(getReductionOps().begin(),
                             getReductionOps().end());
  }

  helper_expr_const_range taskgroup_descriptors() const {
    return helper_expr_const_range(getTaskgroupDescriptors().begin(),
                                   getTaskgroupDescriptors().end());
  }

  helper_expr_range taskgroup_descriptors() {
    return helper_expr_range(getTaskgroupDescriptors().begin(),
                             getTaskgroupDescriptors().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_in_reduction;
  }
};

/// This represents clause 'linear' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp simd linear(a,b : 2)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'linear'
/// with variables 'a', 'b' and linear step '2'.
class OMPLinearClause final
    : public OMPVarListClause<OMPLinearClause>,
      public OMPClauseWithPostUpdate,
      private llvm::TrailingObjects<OMPLinearClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Modifier of 'linear' clause.
  OpenMPLinearClauseKind Modifier = OMPC_LINEAR_val;

  /// Location of linear modifier if any.
  SourceLocation ModifierLoc;

  /// Location of ':'.
  SourceLocation ColonLoc;

  /// Sets the linear step for clause.
  void setStep(Expr *Step) { *(getFinals().end()) = Step; }

  /// Sets the expression to calculate linear step for clause.
  void setCalcStep(Expr *CalcStep) { *(getFinals().end() + 1) = CalcStep; }

  /// Build 'linear' clause with given number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of variables.
  OMPLinearClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                  OpenMPLinearClauseKind Modifier, SourceLocation ModifierLoc,
                  SourceLocation ColonLoc, SourceLocation EndLoc,
                  unsigned NumVars)
      : OMPVarListClause<OMPLinearClause>(OMPC_linear, StartLoc, LParenLoc,
                                          EndLoc, NumVars),
        OMPClauseWithPostUpdate(this), Modifier(Modifier),
        ModifierLoc(ModifierLoc), ColonLoc(ColonLoc) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of variables.
  explicit OMPLinearClause(unsigned NumVars)
      : OMPVarListClause<OMPLinearClause>(OMPC_linear, SourceLocation(),
                                          SourceLocation(), SourceLocation(),
                                          NumVars),
        OMPClauseWithPostUpdate(this) {}

  /// Gets the list of initial values for linear variables.
  ///
  /// There are NumVars expressions with initial values allocated after the
  /// varlist, they are followed by NumVars update expressions (used to update
  /// the linear variable's value on current iteration) and they are followed by
  /// NumVars final expressions (used to calculate the linear variable's
  /// value after the loop body). After these lists, there are 2 helper
  /// expressions - linear step and a helper to calculate it before the
  /// loop body (used when the linear step is not constant):
  ///
  /// { Vars[] /* in OMPVarListClause */; Privates[]; Inits[]; Updates[];
  /// Finals[]; Step; CalcStep; }
  MutableArrayRef<Expr *> getPrivates() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivates() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  MutableArrayRef<Expr *> getInits() {
    return MutableArrayRef<Expr *>(getPrivates().end(), varlist_size());
  }
  ArrayRef<const Expr *> getInits() const {
    return llvm::makeArrayRef(getPrivates().end(), varlist_size());
  }

  /// Sets the list of update expressions for linear variables.
  MutableArrayRef<Expr *> getUpdates() {
    return MutableArrayRef<Expr *>(getInits().end(), varlist_size());
  }
  ArrayRef<const Expr *> getUpdates() const {
    return llvm::makeArrayRef(getInits().end(), varlist_size());
  }

  /// Sets the list of final update expressions for linear variables.
  MutableArrayRef<Expr *> getFinals() {
    return MutableArrayRef<Expr *>(getUpdates().end(), varlist_size());
  }
  ArrayRef<const Expr *> getFinals() const {
    return llvm::makeArrayRef(getUpdates().end(), varlist_size());
  }

  /// Sets the list of the copies of original linear variables.
  /// \param PL List of expressions.
  void setPrivates(ArrayRef<Expr *> PL);

  /// Sets the list of the initial values for linear variables.
  /// \param IL List of expressions.
  void setInits(ArrayRef<Expr *> IL);

public:
  /// Creates clause with a list of variables \a VL and a linear step
  /// \a Step.
  ///
  /// \param C AST Context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param Modifier Modifier of 'linear' clause.
  /// \param ModifierLoc Modifier location.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param PL List of private copies of original variables.
  /// \param IL List of initial values for the variables.
  /// \param Step Linear step.
  /// \param CalcStep Calculation of the linear step.
  /// \param PreInit Statement that must be executed before entering the OpenMP
  /// region with this clause.
  /// \param PostUpdate Expression that must be executed after exit from the
  /// OpenMP region with this clause.
  static OMPLinearClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         OpenMPLinearClauseKind Modifier, SourceLocation ModifierLoc,
         SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef<Expr *> VL,
         ArrayRef<Expr *> PL, ArrayRef<Expr *> IL, Expr *Step, Expr *CalcStep,
         Stmt *PreInit, Expr *PostUpdate);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of variables.
  static OMPLinearClause *CreateEmpty(const ASTContext &C, unsigned NumVars);

  /// Set modifier.
  void setModifier(OpenMPLinearClauseKind Kind) { Modifier = Kind; }

  /// Return modifier.
  OpenMPLinearClauseKind getModifier() const { return Modifier; }

  /// Set modifier location.
  void setModifierLoc(SourceLocation Loc) { ModifierLoc = Loc; }

  /// Return modifier location.
  SourceLocation getModifierLoc() const { return ModifierLoc; }

  /// Sets the location of ':'.
  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }

  /// Returns the location of ':'.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Returns linear step.
  Expr *getStep() { return *(getFinals().end()); }

  /// Returns linear step.
  const Expr *getStep() const { return *(getFinals().end()); }

  /// Returns expression to calculate linear step.
  Expr *getCalcStep() { return *(getFinals().end() + 1); }

  /// Returns expression to calculate linear step.
  const Expr *getCalcStep() const { return *(getFinals().end() + 1); }

  /// Sets the list of update expressions for linear variables.
  /// \param UL List of expressions.
  void setUpdates(ArrayRef<Expr *> UL);

  /// Sets the list of final update expressions for linear variables.
  /// \param FL List of expressions.
  void setFinals(ArrayRef<Expr *> FL);

  using privates_iterator = MutableArrayRef<Expr *>::iterator;
  using privates_const_iterator = ArrayRef<const Expr *>::iterator;
  using privates_range = llvm::iterator_range<privates_iterator>;
  using privates_const_range = llvm::iterator_range<privates_const_iterator>;

  privates_range privates() {
    return privates_range(getPrivates().begin(), getPrivates().end());
  }

  privates_const_range privates() const {
    return privates_const_range(getPrivates().begin(), getPrivates().end());
  }

  using inits_iterator = MutableArrayRef<Expr *>::iterator;
  using inits_const_iterator = ArrayRef<const Expr *>::iterator;
  using inits_range = llvm::iterator_range<inits_iterator>;
  using inits_const_range = llvm::iterator_range<inits_const_iterator>;

  inits_range inits() {
    return inits_range(getInits().begin(), getInits().end());
  }

  inits_const_range inits() const {
    return inits_const_range(getInits().begin(), getInits().end());
  }

  using updates_iterator = MutableArrayRef<Expr *>::iterator;
  using updates_const_iterator = ArrayRef<const Expr *>::iterator;
  using updates_range = llvm::iterator_range<updates_iterator>;
  using updates_const_range = llvm::iterator_range<updates_const_iterator>;

  updates_range updates() {
    return updates_range(getUpdates().begin(), getUpdates().end());
  }

  updates_const_range updates() const {
    return updates_const_range(getUpdates().begin(), getUpdates().end());
  }

  using finals_iterator = MutableArrayRef<Expr *>::iterator;
  using finals_const_iterator = ArrayRef<const Expr *>::iterator;
  using finals_range = llvm::iterator_range<finals_iterator>;
  using finals_const_range = llvm::iterator_range<finals_const_iterator>;

  finals_range finals() {
    return finals_range(getFinals().begin(), getFinals().end());
  }

  finals_const_range finals() const {
    return finals_const_range(getFinals().begin(), getFinals().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_linear;
  }
};

/// This represents clause 'aligned' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp simd aligned(a,b : 8)
/// \endcode
/// In this example directive '#pragma omp simd' has clause 'aligned'
/// with variables 'a', 'b' and alignment '8'.
class OMPAlignedClause final
    : public OMPVarListClause<OMPAlignedClause>,
      private llvm::TrailingObjects<OMPAlignedClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Location of ':'.
  SourceLocation ColonLoc;

  /// Sets the alignment for clause.
  void setAlignment(Expr *A) { *varlist_end() = A; }

  /// Build 'aligned' clause with given number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of variables.
  OMPAlignedClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                   SourceLocation ColonLoc, SourceLocation EndLoc,
                   unsigned NumVars)
      : OMPVarListClause<OMPAlignedClause>(OMPC_aligned, StartLoc, LParenLoc,
                                           EndLoc, NumVars),
        ColonLoc(ColonLoc) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of variables.
  explicit OMPAlignedClause(unsigned NumVars)
      : OMPVarListClause<OMPAlignedClause>(OMPC_aligned, SourceLocation(),
                                           SourceLocation(), SourceLocation(),
                                           NumVars) {}

public:
  /// Creates clause with a list of variables \a VL and alignment \a A.
  ///
  /// \param C AST Context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param ColonLoc Location of ':'.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param A Alignment.
  static OMPAlignedClause *Create(const ASTContext &C, SourceLocation StartLoc,
                                  SourceLocation LParenLoc,
                                  SourceLocation ColonLoc,
                                  SourceLocation EndLoc, ArrayRef<Expr *> VL,
                                  Expr *A);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of variables.
  static OMPAlignedClause *CreateEmpty(const ASTContext &C, unsigned NumVars);

  /// Sets the location of ':'.
  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }

  /// Returns the location of ':'.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Returns alignment.
  Expr *getAlignment() { return *varlist_end(); }

  /// Returns alignment.
  const Expr *getAlignment() const { return *varlist_end(); }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_aligned;
  }
};

/// This represents clause 'copyin' in the '#pragma omp ...' directives.
///
/// \code
/// #pragma omp parallel copyin(a,b)
/// \endcode
/// In this example directive '#pragma omp parallel' has clause 'copyin'
/// with the variables 'a' and 'b'.
class OMPCopyinClause final
    : public OMPVarListClause<OMPCopyinClause>,
      private llvm::TrailingObjects<OMPCopyinClause, Expr *> {
  // Class has 3 additional tail allocated arrays:
  // 1. List of helper expressions for proper generation of assignment operation
  // required for copyin clause. This list represents sources.
  // 2. List of helper expressions for proper generation of assignment operation
  // required for copyin clause. This list represents destinations.
  // 3. List of helper expressions that represents assignment operation:
  // \code
  // DstExprs = SrcExprs;
  // \endcode
  // Required for proper codegen of propagation of master's thread values of
  // threadprivate variables to local instances of that variables in other
  // implicit threads.

  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPCopyinClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                  SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPCopyinClause>(OMPC_copyin, StartLoc, LParenLoc,
                                          EndLoc, N) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPCopyinClause(unsigned N)
      : OMPVarListClause<OMPCopyinClause>(OMPC_copyin, SourceLocation(),
                                          SourceLocation(), SourceLocation(),
                                          N) {}

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent source expression in the final
  /// assignment statement performed by the copyin clause.
  void setSourceExprs(ArrayRef<Expr *> SrcExprs);

  /// Get the list of helper source expressions.
  MutableArrayRef<Expr *> getSourceExprs() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getSourceExprs() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent destination expression in the final
  /// assignment statement performed by the copyin clause.
  void setDestinationExprs(ArrayRef<Expr *> DstExprs);

  /// Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getDestinationExprs() {
    return MutableArrayRef<Expr *>(getSourceExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getDestinationExprs() const {
    return llvm::makeArrayRef(getSourceExprs().end(), varlist_size());
  }

  /// Set list of helper assignment expressions, required for proper
  /// codegen of the clause. These expressions are assignment expressions that
  /// assign source helper expressions to destination helper expressions
  /// correspondingly.
  void setAssignmentOps(ArrayRef<Expr *> AssignmentOps);

  /// Get the list of helper assignment expressions.
  MutableArrayRef<Expr *> getAssignmentOps() {
    return MutableArrayRef<Expr *>(getDestinationExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getAssignmentOps() const {
    return llvm::makeArrayRef(getDestinationExprs().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param SrcExprs List of helper expressions for proper generation of
  /// assignment operation required for copyin clause. This list represents
  /// sources.
  /// \param DstExprs List of helper expressions for proper generation of
  /// assignment operation required for copyin clause. This list represents
  /// destinations.
  /// \param AssignmentOps List of helper expressions that represents assignment
  /// operation:
  /// \code
  /// DstExprs = SrcExprs;
  /// \endcode
  /// Required for proper codegen of propagation of master's thread values of
  /// threadprivate variables to local instances of that variables in other
  /// implicit threads.
  static OMPCopyinClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> VL, ArrayRef<Expr *> SrcExprs,
         ArrayRef<Expr *> DstExprs, ArrayRef<Expr *> AssignmentOps);

  /// Creates an empty clause with \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPCopyinClause *CreateEmpty(const ASTContext &C, unsigned N);

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  helper_expr_const_range source_exprs() const {
    return helper_expr_const_range(getSourceExprs().begin(),
                                   getSourceExprs().end());
  }

  helper_expr_range source_exprs() {
    return helper_expr_range(getSourceExprs().begin(), getSourceExprs().end());
  }

  helper_expr_const_range destination_exprs() const {
    return helper_expr_const_range(getDestinationExprs().begin(),
                                   getDestinationExprs().end());
  }

  helper_expr_range destination_exprs() {
    return helper_expr_range(getDestinationExprs().begin(),
                             getDestinationExprs().end());
  }

  helper_expr_const_range assignment_ops() const {
    return helper_expr_const_range(getAssignmentOps().begin(),
                                   getAssignmentOps().end());
  }

  helper_expr_range assignment_ops() {
    return helper_expr_range(getAssignmentOps().begin(),
                             getAssignmentOps().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_copyin;
  }
};

/// This represents clause 'copyprivate' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp single copyprivate(a,b)
/// \endcode
/// In this example directive '#pragma omp single' has clause 'copyprivate'
/// with the variables 'a' and 'b'.
class OMPCopyprivateClause final
    : public OMPVarListClause<OMPCopyprivateClause>,
      private llvm::TrailingObjects<OMPCopyprivateClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPCopyprivateClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                       SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPCopyprivateClause>(OMPC_copyprivate, StartLoc,
                                               LParenLoc, EndLoc, N) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPCopyprivateClause(unsigned N)
      : OMPVarListClause<OMPCopyprivateClause>(
            OMPC_copyprivate, SourceLocation(), SourceLocation(),
            SourceLocation(), N) {}

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent source expression in the final
  /// assignment statement performed by the copyprivate clause.
  void setSourceExprs(ArrayRef<Expr *> SrcExprs);

  /// Get the list of helper source expressions.
  MutableArrayRef<Expr *> getSourceExprs() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getSourceExprs() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Set list of helper expressions, required for proper codegen of the
  /// clause. These expressions represent destination expression in the final
  /// assignment statement performed by the copyprivate clause.
  void setDestinationExprs(ArrayRef<Expr *> DstExprs);

  /// Get the list of helper destination expressions.
  MutableArrayRef<Expr *> getDestinationExprs() {
    return MutableArrayRef<Expr *>(getSourceExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getDestinationExprs() const {
    return llvm::makeArrayRef(getSourceExprs().end(), varlist_size());
  }

  /// Set list of helper assignment expressions, required for proper
  /// codegen of the clause. These expressions are assignment expressions that
  /// assign source helper expressions to destination helper expressions
  /// correspondingly.
  void setAssignmentOps(ArrayRef<Expr *> AssignmentOps);

  /// Get the list of helper assignment expressions.
  MutableArrayRef<Expr *> getAssignmentOps() {
    return MutableArrayRef<Expr *>(getDestinationExprs().end(), varlist_size());
  }
  ArrayRef<const Expr *> getAssignmentOps() const {
    return llvm::makeArrayRef(getDestinationExprs().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  /// \param SrcExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// sources.
  /// \param DstExprs List of helper expressions for proper generation of
  /// assignment operation required for copyprivate clause. This list represents
  /// destinations.
  /// \param AssignmentOps List of helper expressions that represents assignment
  /// operation:
  /// \code
  /// DstExprs = SrcExprs;
  /// \endcode
  /// Required for proper codegen of final assignment performed by the
  /// copyprivate clause.
  static OMPCopyprivateClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> VL, ArrayRef<Expr *> SrcExprs,
         ArrayRef<Expr *> DstExprs, ArrayRef<Expr *> AssignmentOps);

  /// Creates an empty clause with \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPCopyprivateClause *CreateEmpty(const ASTContext &C, unsigned N);

  using helper_expr_iterator = MutableArrayRef<Expr *>::iterator;
  using helper_expr_const_iterator = ArrayRef<const Expr *>::iterator;
  using helper_expr_range = llvm::iterator_range<helper_expr_iterator>;
  using helper_expr_const_range =
      llvm::iterator_range<helper_expr_const_iterator>;

  helper_expr_const_range source_exprs() const {
    return helper_expr_const_range(getSourceExprs().begin(),
                                   getSourceExprs().end());
  }

  helper_expr_range source_exprs() {
    return helper_expr_range(getSourceExprs().begin(), getSourceExprs().end());
  }

  helper_expr_const_range destination_exprs() const {
    return helper_expr_const_range(getDestinationExprs().begin(),
                                   getDestinationExprs().end());
  }

  helper_expr_range destination_exprs() {
    return helper_expr_range(getDestinationExprs().begin(),
                             getDestinationExprs().end());
  }

  helper_expr_const_range assignment_ops() const {
    return helper_expr_const_range(getAssignmentOps().begin(),
                                   getAssignmentOps().end());
  }

  helper_expr_range assignment_ops() {
    return helper_expr_range(getAssignmentOps().begin(),
                             getAssignmentOps().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_copyprivate;
  }
};

/// This represents implicit clause 'flush' for the '#pragma omp flush'
/// directive.
/// This clause does not exist by itself, it can be only as a part of 'omp
/// flush' directive. This clause is introduced to keep the original structure
/// of \a OMPExecutableDirective class and its derivatives and to use the
/// existing infrastructure of clauses with the list of variables.
///
/// \code
/// #pragma omp flush(a,b)
/// \endcode
/// In this example directive '#pragma omp flush' has implicit clause 'flush'
/// with the variables 'a' and 'b'.
class OMPFlushClause final
    : public OMPVarListClause<OMPFlushClause>,
      private llvm::TrailingObjects<OMPFlushClause, Expr *> {
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  OMPFlushClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                 SourceLocation EndLoc, unsigned N)
      : OMPVarListClause<OMPFlushClause>(OMPC_flush, StartLoc, LParenLoc,
                                         EndLoc, N) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  explicit OMPFlushClause(unsigned N)
      : OMPVarListClause<OMPFlushClause>(OMPC_flush, SourceLocation(),
                                         SourceLocation(), SourceLocation(),
                                         N) {}

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param VL List of references to the variables.
  static OMPFlushClause *Create(const ASTContext &C, SourceLocation StartLoc,
                                SourceLocation LParenLoc, SourceLocation EndLoc,
                                ArrayRef<Expr *> VL);

  /// Creates an empty clause with \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  static OMPFlushClause *CreateEmpty(const ASTContext &C, unsigned N);

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_flush;
  }
};

/// This represents implicit clause 'depend' for the '#pragma omp task'
/// directive.
///
/// \code
/// #pragma omp task depend(in:a,b)
/// \endcode
/// In this example directive '#pragma omp task' with clause 'depend' with the
/// variables 'a' and 'b' with dependency 'in'.
class OMPDependClause final
    : public OMPVarListClause<OMPDependClause>,
      private llvm::TrailingObjects<OMPDependClause, Expr *> {
  friend class OMPClauseReader;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Dependency type (one of in, out, inout).
  OpenMPDependClauseKind DepKind = OMPC_DEPEND_unknown;

  /// Dependency type location.
  SourceLocation DepLoc;

  /// Colon location.
  SourceLocation ColonLoc;

  /// Number of loops, associated with the depend clause.
  unsigned NumLoops = 0;

  /// Build clause with number of variables \a N.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param N Number of the variables in the clause.
  /// \param NumLoops Number of loops that is associated with this depend
  /// clause.
  OMPDependClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                  SourceLocation EndLoc, unsigned N, unsigned NumLoops)
      : OMPVarListClause<OMPDependClause>(OMPC_depend, StartLoc, LParenLoc,
                                          EndLoc, N), NumLoops(NumLoops) {}

  /// Build an empty clause.
  ///
  /// \param N Number of variables.
  /// \param NumLoops Number of loops that is associated with this depend
  /// clause.
  explicit OMPDependClause(unsigned N, unsigned NumLoops)
      : OMPVarListClause<OMPDependClause>(OMPC_depend, SourceLocation(),
                                          SourceLocation(), SourceLocation(),
                                          N),
        NumLoops(NumLoops) {}

  /// Set dependency kind.
  void setDependencyKind(OpenMPDependClauseKind K) { DepKind = K; }

  /// Set dependency kind and its location.
  void setDependencyLoc(SourceLocation Loc) { DepLoc = Loc; }

  /// Set colon location.
  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param DepKind Dependency type.
  /// \param DepLoc Location of the dependency type.
  /// \param ColonLoc Colon location.
  /// \param VL List of references to the variables.
  /// \param NumLoops Number of loops that is associated with this depend
  /// clause.
  static OMPDependClause *Create(const ASTContext &C, SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc,
                                 OpenMPDependClauseKind DepKind,
                                 SourceLocation DepLoc, SourceLocation ColonLoc,
                                 ArrayRef<Expr *> VL, unsigned NumLoops);

  /// Creates an empty clause with \a N variables.
  ///
  /// \param C AST context.
  /// \param N The number of variables.
  /// \param NumLoops Number of loops that is associated with this depend
  /// clause.
  static OMPDependClause *CreateEmpty(const ASTContext &C, unsigned N,
                                      unsigned NumLoops);

  /// Get dependency type.
  OpenMPDependClauseKind getDependencyKind() const { return DepKind; }

  /// Get dependency type location.
  SourceLocation getDependencyLoc() const { return DepLoc; }

  /// Get colon location.
  SourceLocation getColonLoc() const { return ColonLoc; }

  /// Get number of loops associated with the clause.
  unsigned getNumLoops() const { return NumLoops; }

  /// Set the loop data for the depend clauses with 'sink|source' kind of
  /// dependency.
  void setLoopData(unsigned NumLoop, Expr *Cnt);

  /// Get the loop data.
  Expr *getLoopData(unsigned NumLoop);
  const Expr *getLoopData(unsigned NumLoop) const;

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_depend;
  }
};

/// This represents 'device' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp target device(a)
/// \endcode
/// In this example directive '#pragma omp target' has clause 'device'
/// with single expression 'a'.
class OMPDeviceClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Device number.
  Stmt *Device = nullptr;

  /// Set the device number.
  ///
  /// \param E Device number.
  void setDevice(Expr *E) { Device = E; }

public:
  /// Build 'device' clause.
  ///
  /// \param E Expression associated with this clause.
  /// \param CaptureRegion Innermost OpenMP region where expressions in this
  /// clause must be captured.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPDeviceClause(Expr *E, Stmt *HelperE, OpenMPDirectiveKind CaptureRegion,
                  SourceLocation StartLoc, SourceLocation LParenLoc,
                  SourceLocation EndLoc)
      : OMPClause(OMPC_device, StartLoc, EndLoc), OMPClauseWithPreInit(this),
        LParenLoc(LParenLoc), Device(E) {
    setPreInitStmt(HelperE, CaptureRegion);
  }

  /// Build an empty clause.
  OMPDeviceClause()
      : OMPClause(OMPC_device, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return device number.
  Expr *getDevice() { return cast<Expr>(Device); }

  /// Return device number.
  Expr *getDevice() const { return cast<Expr>(Device); }

  child_range children() { return child_range(&Device, &Device + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_device;
  }
};

/// This represents 'threads' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp ordered threads
/// \endcode
/// In this example directive '#pragma omp ordered' has simple 'threads' clause.
class OMPThreadsClause : public OMPClause {
public:
  /// Build 'threads' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPThreadsClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_threads, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPThreadsClause()
      : OMPClause(OMPC_threads, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_threads;
  }
};

/// This represents 'simd' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp ordered simd
/// \endcode
/// In this example directive '#pragma omp ordered' has simple 'simd' clause.
class OMPSIMDClause : public OMPClause {
public:
  /// Build 'simd' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPSIMDClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_simd, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPSIMDClause() : OMPClause(OMPC_simd, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_simd;
  }
};

/// Struct that defines common infrastructure to handle mappable
/// expressions used in OpenMP clauses.
class OMPClauseMappableExprCommon {
public:
  /// Class that represents a component of a mappable expression. E.g.
  /// for an expression S.a, the first component is a declaration reference
  /// expression associated with 'S' and the second is a member expression
  /// associated with the field declaration 'a'. If the expression is an array
  /// subscript it may not have any associated declaration. In that case the
  /// associated declaration is set to nullptr.
  class MappableComponent {
    /// Expression associated with the component.
    Expr *AssociatedExpression = nullptr;

    /// Declaration associated with the declaration. If the component does
    /// not have a declaration (e.g. array subscripts or section), this is set
    /// to nullptr.
    ValueDecl *AssociatedDeclaration = nullptr;

  public:
    explicit MappableComponent() = default;
    explicit MappableComponent(Expr *AssociatedExpression,
                               ValueDecl *AssociatedDeclaration)
        : AssociatedExpression(AssociatedExpression),
          AssociatedDeclaration(
              AssociatedDeclaration
                  ? cast<ValueDecl>(AssociatedDeclaration->getCanonicalDecl())
                  : nullptr) {}

    Expr *getAssociatedExpression() const { return AssociatedExpression; }

    ValueDecl *getAssociatedDeclaration() const {
      return AssociatedDeclaration;
    }
  };

  // List of components of an expression. This first one is the whole
  // expression and the last one is the base expression.
  using MappableExprComponentList = SmallVector<MappableComponent, 8>;
  using MappableExprComponentListRef = ArrayRef<MappableComponent>;

  // List of all component lists associated to the same base declaration.
  // E.g. if both 'S.a' and 'S.b' are a mappable expressions, each will have
  // their component list but the same base declaration 'S'.
  using MappableExprComponentLists = SmallVector<MappableExprComponentList, 8>;
  using MappableExprComponentListsRef = ArrayRef<MappableExprComponentList>;

protected:
  // Return the total number of elements in a list of component lists.
  static unsigned
  getComponentsTotalNumber(MappableExprComponentListsRef ComponentLists);

  // Return the total number of elements in a list of declarations. All
  // declarations are expected to be canonical.
  static unsigned
  getUniqueDeclarationsTotalNumber(ArrayRef<const ValueDecl *> Declarations);
};

/// This represents clauses with a list of expressions that are mappable.
/// Examples of these clauses are 'map' in
/// '#pragma omp target [enter|exit] [data]...' directives, and  'to' and 'from
/// in '#pragma omp target update...' directives.
template <class T>
class OMPMappableExprListClause : public OMPVarListClause<T>,
                                  public OMPClauseMappableExprCommon {
  friend class OMPClauseReader;

  /// Number of unique declarations in this clause.
  unsigned NumUniqueDeclarations;

  /// Number of component lists in this clause.
  unsigned NumComponentLists;

  /// Total number of components in this clause.
  unsigned NumComponents;

protected:
  /// Build a clause for \a NumUniqueDeclarations declarations, \a
  /// NumComponentLists total component lists, and \a NumComponents total
  /// components.
  ///
  /// \param K Kind of the clause.
  /// \param StartLoc Starting location of the clause (the clause keyword).
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause - one
  /// list for each expression in the clause.
  /// \param NumComponents Total number of expression components in the clause.
  OMPMappableExprListClause(OpenMPClauseKind K, SourceLocation StartLoc,
                            SourceLocation LParenLoc, SourceLocation EndLoc,
                            unsigned NumVars, unsigned NumUniqueDeclarations,
                            unsigned NumComponentLists, unsigned NumComponents)
      : OMPVarListClause<T>(K, StartLoc, LParenLoc, EndLoc, NumVars),
        NumUniqueDeclarations(NumUniqueDeclarations),
        NumComponentLists(NumComponentLists), NumComponents(NumComponents) {}

  /// Get the unique declarations that are in the trailing objects of the
  /// class.
  MutableArrayRef<ValueDecl *> getUniqueDeclsRef() {
    return MutableArrayRef<ValueDecl *>(
        static_cast<T *>(this)->template getTrailingObjects<ValueDecl *>(),
        NumUniqueDeclarations);
  }

  /// Get the unique declarations that are in the trailing objects of the
  /// class.
  ArrayRef<ValueDecl *> getUniqueDeclsRef() const {
    return ArrayRef<ValueDecl *>(
        static_cast<const T *>(this)
            ->template getTrailingObjects<ValueDecl *>(),
        NumUniqueDeclarations);
  }

  /// Set the unique declarations that are in the trailing objects of the
  /// class.
  void setUniqueDecls(ArrayRef<ValueDecl *> UDs) {
    assert(UDs.size() == NumUniqueDeclarations &&
           "Unexpected amount of unique declarations.");
    std::copy(UDs.begin(), UDs.end(), getUniqueDeclsRef().begin());
  }

  /// Get the number of lists per declaration that are in the trailing
  /// objects of the class.
  MutableArrayRef<unsigned> getDeclNumListsRef() {
    return MutableArrayRef<unsigned>(
        static_cast<T *>(this)->template getTrailingObjects<unsigned>(),
        NumUniqueDeclarations);
  }

  /// Get the number of lists per declaration that are in the trailing
  /// objects of the class.
  ArrayRef<unsigned> getDeclNumListsRef() const {
    return ArrayRef<unsigned>(
        static_cast<const T *>(this)->template getTrailingObjects<unsigned>(),
        NumUniqueDeclarations);
  }

  /// Set the number of lists per declaration that are in the trailing
  /// objects of the class.
  void setDeclNumLists(ArrayRef<unsigned> DNLs) {
    assert(DNLs.size() == NumUniqueDeclarations &&
           "Unexpected amount of list numbers.");
    std::copy(DNLs.begin(), DNLs.end(), getDeclNumListsRef().begin());
  }

  /// Get the cumulative component lists sizes that are in the trailing
  /// objects of the class. They are appended after the number of lists.
  MutableArrayRef<unsigned> getComponentListSizesRef() {
    return MutableArrayRef<unsigned>(
        static_cast<T *>(this)->template getTrailingObjects<unsigned>() +
            NumUniqueDeclarations,
        NumComponentLists);
  }

  /// Get the cumulative component lists sizes that are in the trailing
  /// objects of the class. They are appended after the number of lists.
  ArrayRef<unsigned> getComponentListSizesRef() const {
    return ArrayRef<unsigned>(
        static_cast<const T *>(this)->template getTrailingObjects<unsigned>() +
            NumUniqueDeclarations,
        NumComponentLists);
  }

  /// Set the cumulative component lists sizes that are in the trailing
  /// objects of the class.
  void setComponentListSizes(ArrayRef<unsigned> CLSs) {
    assert(CLSs.size() == NumComponentLists &&
           "Unexpected amount of component lists.");
    std::copy(CLSs.begin(), CLSs.end(), getComponentListSizesRef().begin());
  }

  /// Get the components that are in the trailing objects of the class.
  MutableArrayRef<MappableComponent> getComponentsRef() {
    return MutableArrayRef<MappableComponent>(
        static_cast<T *>(this)
            ->template getTrailingObjects<MappableComponent>(),
        NumComponents);
  }

  /// Get the components that are in the trailing objects of the class.
  ArrayRef<MappableComponent> getComponentsRef() const {
    return ArrayRef<MappableComponent>(
        static_cast<const T *>(this)
            ->template getTrailingObjects<MappableComponent>(),
        NumComponents);
  }

  /// Set the components that are in the trailing objects of the class.
  /// This requires the list sizes so that it can also fill the original
  /// expressions, which are the first component of each list.
  void setComponents(ArrayRef<MappableComponent> Components,
                     ArrayRef<unsigned> CLSs) {
    assert(Components.size() == NumComponents &&
           "Unexpected amount of component lists.");
    assert(CLSs.size() == NumComponentLists &&
           "Unexpected amount of list sizes.");
    std::copy(Components.begin(), Components.end(), getComponentsRef().begin());
  }

  /// Fill the clause information from the list of declarations and
  /// associated component lists.
  void setClauseInfo(ArrayRef<ValueDecl *> Declarations,
                     MappableExprComponentListsRef ComponentLists) {
    // Perform some checks to make sure the data sizes are consistent with the
    // information available when the clause was created.
    assert(getUniqueDeclarationsTotalNumber(Declarations) ==
               NumUniqueDeclarations &&
           "Unexpected number of mappable expression info entries!");
    assert(getComponentsTotalNumber(ComponentLists) == NumComponents &&
           "Unexpected total number of components!");
    assert(Declarations.size() == ComponentLists.size() &&
           "Declaration and component lists size is not consistent!");
    assert(Declarations.size() == NumComponentLists &&
           "Unexpected declaration and component lists size!");

    // Organize the components by declaration and retrieve the original
    // expression. Original expressions are always the first component of the
    // mappable component list.
    llvm::MapVector<ValueDecl *, SmallVector<MappableExprComponentListRef, 8>>
        ComponentListMap;
    {
      auto CI = ComponentLists.begin();
      for (auto DI = Declarations.begin(), DE = Declarations.end(); DI != DE;
           ++DI, ++CI) {
        assert(!CI->empty() && "Invalid component list!");
        ComponentListMap[*DI].push_back(*CI);
      }
    }

    // Iterators of the target storage.
    auto UniqueDeclarations = getUniqueDeclsRef();
    auto UDI = UniqueDeclarations.begin();

    auto DeclNumLists = getDeclNumListsRef();
    auto DNLI = DeclNumLists.begin();

    auto ComponentListSizes = getComponentListSizesRef();
    auto CLSI = ComponentListSizes.begin();

    auto Components = getComponentsRef();
    auto CI = Components.begin();

    // Variable to compute the accumulation of the number of components.
    unsigned PrevSize = 0u;

    // Scan all the declarations and associated component lists.
    for (auto &M : ComponentListMap) {
      // The declaration.
      auto *D = M.first;
      // The component lists.
      auto CL = M.second;

      // Initialize the entry.
      *UDI = D;
      ++UDI;

      *DNLI = CL.size();
      ++DNLI;

      // Obtain the cumulative sizes and concatenate all the components in the
      // reserved storage.
      for (auto C : CL) {
        // Accumulate with the previous size.
        PrevSize += C.size();

        // Save the size.
        *CLSI = PrevSize;
        ++CLSI;

        // Append components after the current components iterator.
        CI = std::copy(C.begin(), C.end(), CI);
      }
    }
  }

public:
  /// Return the number of unique base declarations in this clause.
  unsigned getUniqueDeclarationsNum() const { return NumUniqueDeclarations; }

  /// Return the number of lists derived from the clause expressions.
  unsigned getTotalComponentListNum() const { return NumComponentLists; }

  /// Return the total number of components in all lists derived from the
  /// clause.
  unsigned getTotalComponentsNum() const { return NumComponents; }

  /// Iterator that browse the components by lists. It also allows
  /// browsing components of a single declaration.
  class const_component_lists_iterator
      : public llvm::iterator_adaptor_base<
            const_component_lists_iterator,
            MappableExprComponentListRef::const_iterator,
            std::forward_iterator_tag, MappableComponent, ptrdiff_t,
            MappableComponent, MappableComponent> {
    // The declaration the iterator currently refers to.
    ArrayRef<ValueDecl *>::iterator DeclCur;

    // The list number associated with the current declaration.
    ArrayRef<unsigned>::iterator NumListsCur;

    // Remaining lists for the current declaration.
    unsigned RemainingLists = 0;

    // The cumulative size of the previous list, or zero if there is no previous
    // list.
    unsigned PrevListSize = 0;

    // The cumulative sizes of the current list - it will delimit the remaining
    // range of interest.
    ArrayRef<unsigned>::const_iterator ListSizeCur;
    ArrayRef<unsigned>::const_iterator ListSizeEnd;

    // Iterator to the end of the components storage.
    MappableExprComponentListRef::const_iterator End;

  public:
    /// Construct an iterator that scans all lists.
    explicit const_component_lists_iterator(
        ArrayRef<ValueDecl *> UniqueDecls, ArrayRef<unsigned> DeclsListNum,
        ArrayRef<unsigned> CumulativeListSizes,
        MappableExprComponentListRef Components)
        : const_component_lists_iterator::iterator_adaptor_base(
              Components.begin()),
          DeclCur(UniqueDecls.begin()), NumListsCur(DeclsListNum.begin()),
          ListSizeCur(CumulativeListSizes.begin()),
          ListSizeEnd(CumulativeListSizes.end()), End(Components.end()) {
      assert(UniqueDecls.size() == DeclsListNum.size() &&
             "Inconsistent number of declarations and list sizes!");
      if (!DeclsListNum.empty())
        RemainingLists = *NumListsCur;
    }

    /// Construct an iterator that scan lists for a given declaration \a
    /// Declaration.
    explicit const_component_lists_iterator(
        const ValueDecl *Declaration, ArrayRef<ValueDecl *> UniqueDecls,
        ArrayRef<unsigned> DeclsListNum, ArrayRef<unsigned> CumulativeListSizes,
        MappableExprComponentListRef Components)
        : const_component_lists_iterator(UniqueDecls, DeclsListNum,
                                         CumulativeListSizes, Components) {
      // Look for the desired declaration. While we are looking for it, we
      // update the state so that we know the component where a given list
      // starts.
      for (; DeclCur != UniqueDecls.end(); ++DeclCur, ++NumListsCur) {
        if (*DeclCur == Declaration)
          break;

        assert(*NumListsCur > 0 && "No lists associated with declaration??");

        // Skip the lists associated with the current declaration, but save the
        // last list size that was skipped.
        std::advance(ListSizeCur, *NumListsCur - 1);
        PrevListSize = *ListSizeCur;
        ++ListSizeCur;
      }

      // If we didn't find any declaration, advance the iterator to after the
      // last component and set remaining lists to zero.
      if (ListSizeCur == CumulativeListSizes.end()) {
        this->I = End;
        RemainingLists = 0u;
        return;
      }

      // Set the remaining lists with the total number of lists of the current
      // declaration.
      RemainingLists = *NumListsCur;

      // Adjust the list size end iterator to the end of the relevant range.
      ListSizeEnd = ListSizeCur;
      std::advance(ListSizeEnd, RemainingLists);

      // Given that the list sizes are cumulative, the index of the component
      // that start the list is the size of the previous list.
      std::advance(this->I, PrevListSize);
    }

    // Return the array with the current list. The sizes are cumulative, so the
    // array size is the difference between the current size and previous one.
    std::pair<const ValueDecl *, MappableExprComponentListRef>
    operator*() const {
      assert(ListSizeCur != ListSizeEnd && "Invalid iterator!");
      return std::make_pair(
          *DeclCur,
          MappableExprComponentListRef(&*this->I, *ListSizeCur - PrevListSize));
    }
    std::pair<const ValueDecl *, MappableExprComponentListRef>
    operator->() const {
      return **this;
    }

    // Skip the components of the current list.
    const_component_lists_iterator &operator++() {
      assert(ListSizeCur != ListSizeEnd && RemainingLists &&
             "Invalid iterator!");

      // If we don't have more lists just skip all the components. Otherwise,
      // advance the iterator by the number of components in the current list.
      if (std::next(ListSizeCur) == ListSizeEnd) {
        this->I = End;
        RemainingLists = 0;
      } else {
        std::advance(this->I, *ListSizeCur - PrevListSize);
        PrevListSize = *ListSizeCur;

        // We are done with a declaration, move to the next one.
        if (!(--RemainingLists)) {
          ++DeclCur;
          ++NumListsCur;
          RemainingLists = *NumListsCur;
          assert(RemainingLists && "No lists in the following declaration??");
        }
      }

      ++ListSizeCur;
      return *this;
    }
  };

  using const_component_lists_range =
      llvm::iterator_range<const_component_lists_iterator>;

  /// Iterators for all component lists.
  const_component_lists_iterator component_lists_begin() const {
    return const_component_lists_iterator(
        getUniqueDeclsRef(), getDeclNumListsRef(), getComponentListSizesRef(),
        getComponentsRef());
  }
  const_component_lists_iterator component_lists_end() const {
    return const_component_lists_iterator(
        ArrayRef<ValueDecl *>(), ArrayRef<unsigned>(), ArrayRef<unsigned>(),
        MappableExprComponentListRef(getComponentsRef().end(),
                                     getComponentsRef().end()));
  }
  const_component_lists_range component_lists() const {
    return {component_lists_begin(), component_lists_end()};
  }

  /// Iterators for component lists associated with the provided
  /// declaration.
  const_component_lists_iterator
  decl_component_lists_begin(const ValueDecl *VD) const {
    return const_component_lists_iterator(
        VD, getUniqueDeclsRef(), getDeclNumListsRef(),
        getComponentListSizesRef(), getComponentsRef());
  }
  const_component_lists_iterator decl_component_lists_end() const {
    return component_lists_end();
  }
  const_component_lists_range decl_component_lists(const ValueDecl *VD) const {
    return {decl_component_lists_begin(VD), decl_component_lists_end()};
  }

  /// Iterators to access all the declarations, number of lists, list sizes, and
  /// components.
  using const_all_decls_iterator = ArrayRef<ValueDecl *>::iterator;
  using const_all_decls_range = llvm::iterator_range<const_all_decls_iterator>;

  const_all_decls_range all_decls() const {
    auto A = getUniqueDeclsRef();
    return const_all_decls_range(A.begin(), A.end());
  }

  using const_all_num_lists_iterator = ArrayRef<unsigned>::iterator;
  using const_all_num_lists_range =
      llvm::iterator_range<const_all_num_lists_iterator>;

  const_all_num_lists_range all_num_lists() const {
    auto A = getDeclNumListsRef();
    return const_all_num_lists_range(A.begin(), A.end());
  }

  using const_all_lists_sizes_iterator = ArrayRef<unsigned>::iterator;
  using const_all_lists_sizes_range =
      llvm::iterator_range<const_all_lists_sizes_iterator>;

  const_all_lists_sizes_range all_lists_sizes() const {
    auto A = getComponentListSizesRef();
    return const_all_lists_sizes_range(A.begin(), A.end());
  }

  using const_all_components_iterator = ArrayRef<MappableComponent>::iterator;
  using const_all_components_range =
      llvm::iterator_range<const_all_components_iterator>;

  const_all_components_range all_components() const {
    auto A = getComponentsRef();
    return const_all_components_range(A.begin(), A.end());
  }
};

/// This represents clause 'map' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp target map(a,b)
/// \endcode
/// In this example directive '#pragma omp target' has clause 'map'
/// with the variables 'a' and 'b'.
class OMPMapClause final : public OMPMappableExprListClause<OMPMapClause>,
                           private llvm::TrailingObjects<
                               OMPMapClause, Expr *, ValueDecl *, unsigned,
                               OMPClauseMappableExprCommon::MappableComponent> {
  friend class OMPClauseReader;
  friend OMPMappableExprListClause;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Define the sizes of each trailing object array except the last one. This
  /// is required for TrailingObjects to work properly.
  size_t numTrailingObjects(OverloadToken<Expr *>) const {
    return varlist_size();
  }
  size_t numTrailingObjects(OverloadToken<ValueDecl *>) const {
    return getUniqueDeclarationsNum();
  }
  size_t numTrailingObjects(OverloadToken<unsigned>) const {
    return getUniqueDeclarationsNum() + getTotalComponentListNum();
  }

  /// Map type modifier for the 'map' clause.
  OpenMPMapClauseKind MapTypeModifier = OMPC_MAP_unknown;

  /// Map type for the 'map' clause.
  OpenMPMapClauseKind MapType = OMPC_MAP_unknown;

  /// Is this an implicit map type or not.
  bool MapTypeIsImplicit = false;

  /// Location of the map type.
  SourceLocation MapLoc;

  /// Colon location.
  SourceLocation ColonLoc;

  /// Build a clause for \a NumVars listed expressions, \a
  /// NumUniqueDeclarations declarations, \a NumComponentLists total component
  /// lists, and \a NumComponents total expression components.
  ///
  /// \param MapTypeModifier Map type modifier.
  /// \param MapType Map type.
  /// \param MapTypeIsImplicit Map type is inferred implicitly.
  /// \param MapLoc Location of the map type.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPMapClause(OpenMPMapClauseKind MapTypeModifier,
                        OpenMPMapClauseKind MapType, bool MapTypeIsImplicit,
                        SourceLocation MapLoc, SourceLocation StartLoc,
                        SourceLocation LParenLoc, SourceLocation EndLoc,
                        unsigned NumVars, unsigned NumUniqueDeclarations,
                        unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_map, StartLoc, LParenLoc, EndLoc,
                                  NumVars, NumUniqueDeclarations,
                                  NumComponentLists, NumComponents),
        MapTypeModifier(MapTypeModifier), MapType(MapType),
        MapTypeIsImplicit(MapTypeIsImplicit), MapLoc(MapLoc) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPMapClause(unsigned NumVars, unsigned NumUniqueDeclarations,
                        unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(
            OMPC_map, SourceLocation(), SourceLocation(), SourceLocation(),
            NumVars, NumUniqueDeclarations, NumComponentLists, NumComponents) {}

  /// Set type modifier for the clause.
  ///
  /// \param T Type Modifier for the clause.
  void setMapTypeModifier(OpenMPMapClauseKind T) { MapTypeModifier = T; }

  /// Set type for the clause.
  ///
  /// \param T Type for the clause.
  void setMapType(OpenMPMapClauseKind T) { MapType = T; }

  /// Set type location.
  ///
  /// \param TLoc Type location.
  void setMapLoc(SourceLocation TLoc) { MapLoc = TLoc; }

  /// Set colon location.
  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }

public:
  /// Creates clause with a list of variables \a VL.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param Vars The original expression used in the clause.
  /// \param Declarations Declarations used in the clause.
  /// \param ComponentLists Component lists used in the clause.
  /// \param TypeModifier Map type modifier.
  /// \param Type Map type.
  /// \param TypeIsImplicit Map type is inferred implicitly.
  /// \param TypeLoc Location of the map type.
  static OMPMapClause *Create(const ASTContext &C, SourceLocation StartLoc,
                              SourceLocation LParenLoc, SourceLocation EndLoc,
                              ArrayRef<Expr *> Vars,
                              ArrayRef<ValueDecl *> Declarations,
                              MappableExprComponentListsRef ComponentLists,
                              OpenMPMapClauseKind TypeModifier,
                              OpenMPMapClauseKind Type, bool TypeIsImplicit,
                              SourceLocation TypeLoc);

  /// Creates an empty clause with the place for \a NumVars original
  /// expressions, \a NumUniqueDeclarations declarations, \NumComponentLists
  /// lists, and \a NumComponents expression components.
  ///
  /// \param C AST context.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of unique base declarations in this
  /// clause.
  /// \param NumComponents Total number of expression components in the clause.
  static OMPMapClause *CreateEmpty(const ASTContext &C, unsigned NumVars,
                                   unsigned NumUniqueDeclarations,
                                   unsigned NumComponentLists,
                                   unsigned NumComponents);

  /// Fetches mapping kind for the clause.
  OpenMPMapClauseKind getMapType() const LLVM_READONLY { return MapType; }

  /// Is this an implicit map type?
  /// We have to capture 'IsMapTypeImplicit' from the parser for more
  /// informative error messages.  It helps distinguish map(r) from
  /// map(tofrom: r), which is important to print more helpful error
  /// messages for some target directives.
  bool isImplicitMapType() const LLVM_READONLY { return MapTypeIsImplicit; }

  /// Fetches the map type modifier for the clause.
  OpenMPMapClauseKind getMapTypeModifier() const LLVM_READONLY {
    return MapTypeModifier;
  }

  /// Fetches location of clause mapping kind.
  SourceLocation getMapLoc() const LLVM_READONLY { return MapLoc; }

  /// Get colon location.
  SourceLocation getColonLoc() const { return ColonLoc; }

  child_range children() {
    return child_range(
        reinterpret_cast<Stmt **>(varlist_begin()),
        reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_map;
  }
};

/// This represents 'num_teams' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp teams num_teams(n)
/// \endcode
/// In this example directive '#pragma omp teams' has clause 'num_teams'
/// with single expression 'n'.
class OMPNumTeamsClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// NumTeams number.
  Stmt *NumTeams = nullptr;

  /// Set the NumTeams number.
  ///
  /// \param E NumTeams number.
  void setNumTeams(Expr *E) { NumTeams = E; }

public:
  /// Build 'num_teams' clause.
  ///
  /// \param E Expression associated with this clause.
  /// \param HelperE Helper Expression associated with this clause.
  /// \param CaptureRegion Innermost OpenMP region where expressions in this
  /// clause must be captured.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPNumTeamsClause(Expr *E, Stmt *HelperE, OpenMPDirectiveKind CaptureRegion,
                    SourceLocation StartLoc, SourceLocation LParenLoc,
                    SourceLocation EndLoc)
      : OMPClause(OMPC_num_teams, StartLoc, EndLoc), OMPClauseWithPreInit(this),
        LParenLoc(LParenLoc), NumTeams(E) {
    setPreInitStmt(HelperE, CaptureRegion);
  }

  /// Build an empty clause.
  OMPNumTeamsClause()
      : OMPClause(OMPC_num_teams, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return NumTeams number.
  Expr *getNumTeams() { return cast<Expr>(NumTeams); }

  /// Return NumTeams number.
  Expr *getNumTeams() const { return cast<Expr>(NumTeams); }

  child_range children() { return child_range(&NumTeams, &NumTeams + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_num_teams;
  }
};

/// This represents 'thread_limit' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp teams thread_limit(n)
/// \endcode
/// In this example directive '#pragma omp teams' has clause 'thread_limit'
/// with single expression 'n'.
class OMPThreadLimitClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// ThreadLimit number.
  Stmt *ThreadLimit = nullptr;

  /// Set the ThreadLimit number.
  ///
  /// \param E ThreadLimit number.
  void setThreadLimit(Expr *E) { ThreadLimit = E; }

public:
  /// Build 'thread_limit' clause.
  ///
  /// \param E Expression associated with this clause.
  /// \param HelperE Helper Expression associated with this clause.
  /// \param CaptureRegion Innermost OpenMP region where expressions in this
  /// clause must be captured.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPThreadLimitClause(Expr *E, Stmt *HelperE,
                       OpenMPDirectiveKind CaptureRegion,
                       SourceLocation StartLoc, SourceLocation LParenLoc,
                       SourceLocation EndLoc)
      : OMPClause(OMPC_thread_limit, StartLoc, EndLoc),
        OMPClauseWithPreInit(this), LParenLoc(LParenLoc), ThreadLimit(E) {
    setPreInitStmt(HelperE, CaptureRegion);
  }

  /// Build an empty clause.
  OMPThreadLimitClause()
      : OMPClause(OMPC_thread_limit, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return ThreadLimit number.
  Expr *getThreadLimit() { return cast<Expr>(ThreadLimit); }

  /// Return ThreadLimit number.
  Expr *getThreadLimit() const { return cast<Expr>(ThreadLimit); }

  child_range children() { return child_range(&ThreadLimit, &ThreadLimit + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_thread_limit;
  }
};

/// This represents 'priority' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp task priority(n)
/// \endcode
/// In this example directive '#pragma omp teams' has clause 'priority' with
/// single expression 'n'.
class OMPPriorityClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Priority number.
  Stmt *Priority = nullptr;

  /// Set the Priority number.
  ///
  /// \param E Priority number.
  void setPriority(Expr *E) { Priority = E; }

public:
  /// Build 'priority' clause.
  ///
  /// \param E Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPPriorityClause(Expr *E, SourceLocation StartLoc, SourceLocation LParenLoc,
                    SourceLocation EndLoc)
      : OMPClause(OMPC_priority, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Priority(E) {}

  /// Build an empty clause.
  OMPPriorityClause()
      : OMPClause(OMPC_priority, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return Priority number.
  Expr *getPriority() { return cast<Expr>(Priority); }

  /// Return Priority number.
  Expr *getPriority() const { return cast<Expr>(Priority); }

  child_range children() { return child_range(&Priority, &Priority + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_priority;
  }
};

/// This represents 'grainsize' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp taskloop grainsize(4)
/// \endcode
/// In this example directive '#pragma omp taskloop' has clause 'grainsize'
/// with single expression '4'.
class OMPGrainsizeClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Safe iteration space distance.
  Stmt *Grainsize = nullptr;

  /// Set safelen.
  void setGrainsize(Expr *Size) { Grainsize = Size; }

public:
  /// Build 'grainsize' clause.
  ///
  /// \param Size Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
                     SourceLocation LParenLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_grainsize, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Grainsize(Size) {}

  /// Build an empty clause.
  explicit OMPGrainsizeClause()
      : OMPClause(OMPC_grainsize, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return safe iteration space distance.
  Expr *getGrainsize() const { return cast_or_null<Expr>(Grainsize); }

  child_range children() { return child_range(&Grainsize, &Grainsize + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_grainsize;
  }
};

/// This represents 'nogroup' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp taskloop nogroup
/// \endcode
/// In this example directive '#pragma omp taskloop' has 'nogroup' clause.
class OMPNogroupClause : public OMPClause {
public:
  /// Build 'nogroup' clause.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPNogroupClause(SourceLocation StartLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_nogroup, StartLoc, EndLoc) {}

  /// Build an empty clause.
  OMPNogroupClause()
      : OMPClause(OMPC_nogroup, SourceLocation(), SourceLocation()) {}

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_nogroup;
  }
};

/// This represents 'num_tasks' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp taskloop num_tasks(4)
/// \endcode
/// In this example directive '#pragma omp taskloop' has clause 'num_tasks'
/// with single expression '4'.
class OMPNumTasksClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Safe iteration space distance.
  Stmt *NumTasks = nullptr;

  /// Set safelen.
  void setNumTasks(Expr *Size) { NumTasks = Size; }

public:
  /// Build 'num_tasks' clause.
  ///
  /// \param Size Expression associated with this clause.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  OMPNumTasksClause(Expr *Size, SourceLocation StartLoc,
                    SourceLocation LParenLoc, SourceLocation EndLoc)
      : OMPClause(OMPC_num_tasks, StartLoc, EndLoc), LParenLoc(LParenLoc),
        NumTasks(Size) {}

  /// Build an empty clause.
  explicit OMPNumTasksClause()
      : OMPClause(OMPC_num_tasks, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Return safe iteration space distance.
  Expr *getNumTasks() const { return cast_or_null<Expr>(NumTasks); }

  child_range children() { return child_range(&NumTasks, &NumTasks + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_num_tasks;
  }
};

/// This represents 'hint' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp critical (name) hint(6)
/// \endcode
/// In this example directive '#pragma omp critical' has name 'name' and clause
/// 'hint' with argument '6'.
class OMPHintClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Hint expression of the 'hint' clause.
  Stmt *Hint = nullptr;

  /// Set hint expression.
  void setHint(Expr *H) { Hint = H; }

public:
  /// Build 'hint' clause with expression \a Hint.
  ///
  /// \param Hint Hint expression.
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param EndLoc Ending location of the clause.
  OMPHintClause(Expr *Hint, SourceLocation StartLoc, SourceLocation LParenLoc,
                SourceLocation EndLoc)
      : OMPClause(OMPC_hint, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Hint(Hint) {}

  /// Build an empty clause.
  OMPHintClause() : OMPClause(OMPC_hint, SourceLocation(), SourceLocation()) {}

  /// Sets the location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Returns the location of '('.
  SourceLocation getLParenLoc() const { return LParenLoc; }

  /// Returns number of threads.
  Expr *getHint() const { return cast_or_null<Expr>(Hint); }

  child_range children() { return child_range(&Hint, &Hint + 1); }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_hint;
  }
};

/// This represents 'dist_schedule' clause in the '#pragma omp ...'
/// directive.
///
/// \code
/// #pragma omp distribute dist_schedule(static, 3)
/// \endcode
/// In this example directive '#pragma omp distribute' has 'dist_schedule'
/// clause with arguments 'static' and '3'.
class OMPDistScheduleClause : public OMPClause, public OMPClauseWithPreInit {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// A kind of the 'schedule' clause.
  OpenMPDistScheduleClauseKind Kind = OMPC_DIST_SCHEDULE_unknown;

  /// Start location of the schedule kind in source code.
  SourceLocation KindLoc;

  /// Location of ',' (if any).
  SourceLocation CommaLoc;

  /// Chunk size.
  Expr *ChunkSize = nullptr;

  /// Set schedule kind.
  ///
  /// \param K Schedule kind.
  void setDistScheduleKind(OpenMPDistScheduleClauseKind K) { Kind = K; }

  /// Sets the location of '('.
  ///
  /// \param Loc Location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Set schedule kind start location.
  ///
  /// \param KLoc Schedule kind location.
  void setDistScheduleKindLoc(SourceLocation KLoc) { KindLoc = KLoc; }

  /// Set location of ','.
  ///
  /// \param Loc Location of ','.
  void setCommaLoc(SourceLocation Loc) { CommaLoc = Loc; }

  /// Set chunk size.
  ///
  /// \param E Chunk size.
  void setChunkSize(Expr *E) { ChunkSize = E; }

public:
  /// Build 'dist_schedule' clause with schedule kind \a Kind and chunk
  /// size expression \a ChunkSize.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param KLoc Starting location of the argument.
  /// \param CommaLoc Location of ','.
  /// \param EndLoc Ending location of the clause.
  /// \param Kind DistSchedule kind.
  /// \param ChunkSize Chunk size.
  /// \param HelperChunkSize Helper chunk size for combined directives.
  OMPDistScheduleClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                        SourceLocation KLoc, SourceLocation CommaLoc,
                        SourceLocation EndLoc,
                        OpenMPDistScheduleClauseKind Kind, Expr *ChunkSize,
                        Stmt *HelperChunkSize)
      : OMPClause(OMPC_dist_schedule, StartLoc, EndLoc),
        OMPClauseWithPreInit(this), LParenLoc(LParenLoc), Kind(Kind),
        KindLoc(KLoc), CommaLoc(CommaLoc), ChunkSize(ChunkSize) {
    setPreInitStmt(HelperChunkSize);
  }

  /// Build an empty clause.
  explicit OMPDistScheduleClause()
      : OMPClause(OMPC_dist_schedule, SourceLocation(), SourceLocation()),
        OMPClauseWithPreInit(this) {}

  /// Get kind of the clause.
  OpenMPDistScheduleClauseKind getDistScheduleKind() const { return Kind; }

  /// Get location of '('.
  SourceLocation getLParenLoc() { return LParenLoc; }

  /// Get kind location.
  SourceLocation getDistScheduleKindLoc() { return KindLoc; }

  /// Get location of ','.
  SourceLocation getCommaLoc() { return CommaLoc; }

  /// Get chunk size.
  Expr *getChunkSize() { return ChunkSize; }

  /// Get chunk size.
  const Expr *getChunkSize() const { return ChunkSize; }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(&ChunkSize),
                       reinterpret_cast<Stmt **>(&ChunkSize) + 1);
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_dist_schedule;
  }
};

/// This represents 'defaultmap' clause in the '#pragma omp ...' directive.
///
/// \code
/// #pragma omp target defaultmap(tofrom: scalar)
/// \endcode
/// In this example directive '#pragma omp target' has 'defaultmap' clause of kind
/// 'scalar' with modifier 'tofrom'.
class OMPDefaultmapClause : public OMPClause {
  friend class OMPClauseReader;

  /// Location of '('.
  SourceLocation LParenLoc;

  /// Modifiers for 'defaultmap' clause.
  OpenMPDefaultmapClauseModifier Modifier = OMPC_DEFAULTMAP_MODIFIER_unknown;

  /// Locations of modifiers.
  SourceLocation ModifierLoc;

  /// A kind of the 'defaultmap' clause.
  OpenMPDefaultmapClauseKind Kind = OMPC_DEFAULTMAP_unknown;

  /// Start location of the defaultmap kind in source code.
  SourceLocation KindLoc;

  /// Set defaultmap kind.
  ///
  /// \param K Defaultmap kind.
  void setDefaultmapKind(OpenMPDefaultmapClauseKind K) { Kind = K; }

  /// Set the defaultmap modifier.
  ///
  /// \param M Defaultmap modifier.
  void setDefaultmapModifier(OpenMPDefaultmapClauseModifier M) {
    Modifier = M;
  }

  /// Set location of the defaultmap modifier.
  void setDefaultmapModifierLoc(SourceLocation Loc) {
    ModifierLoc = Loc;
  }

  /// Sets the location of '('.
  ///
  /// \param Loc Location of '('.
  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }

  /// Set defaultmap kind start location.
  ///
  /// \param KLoc Defaultmap kind location.
  void setDefaultmapKindLoc(SourceLocation KLoc) { KindLoc = KLoc; }

public:
  /// Build 'defaultmap' clause with defaultmap kind \a Kind
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param LParenLoc Location of '('.
  /// \param KLoc Starting location of the argument.
  /// \param EndLoc Ending location of the clause.
  /// \param Kind Defaultmap kind.
  /// \param M The modifier applied to 'defaultmap' clause.
  /// \param MLoc Location of the modifier
  OMPDefaultmapClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                      SourceLocation MLoc, SourceLocation KLoc,
                      SourceLocation EndLoc, OpenMPDefaultmapClauseKind Kind,
                      OpenMPDefaultmapClauseModifier M)
      : OMPClause(OMPC_defaultmap, StartLoc, EndLoc), LParenLoc(LParenLoc),
        Modifier(M), ModifierLoc(MLoc), Kind(Kind), KindLoc(KLoc) {}

  /// Build an empty clause.
  explicit OMPDefaultmapClause()
      : OMPClause(OMPC_defaultmap, SourceLocation(), SourceLocation()) {}

  /// Get kind of the clause.
  OpenMPDefaultmapClauseKind getDefaultmapKind() const { return Kind; }

  /// Get the modifier of the clause.
  OpenMPDefaultmapClauseModifier getDefaultmapModifier() const {
    return Modifier;
  }

  /// Get location of '('.
  SourceLocation getLParenLoc() { return LParenLoc; }

  /// Get kind location.
  SourceLocation getDefaultmapKindLoc() { return KindLoc; }

  /// Get the modifier location.
  SourceLocation getDefaultmapModifierLoc() const {
    return ModifierLoc;
  }

  child_range children() {
    return child_range(child_iterator(), child_iterator());
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_defaultmap;
  }
};

/// This represents clause 'to' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp target update to(a,b)
/// \endcode
/// In this example directive '#pragma omp target update' has clause 'to'
/// with the variables 'a' and 'b'.
class OMPToClause final : public OMPMappableExprListClause<OMPToClause>,
                          private llvm::TrailingObjects<
                              OMPToClause, Expr *, ValueDecl *, unsigned,
                              OMPClauseMappableExprCommon::MappableComponent> {
  friend class OMPClauseReader;
  friend OMPMappableExprListClause;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPToClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                       SourceLocation EndLoc, unsigned NumVars,
                       unsigned NumUniqueDeclarations,
                       unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_to, StartLoc, LParenLoc, EndLoc, NumVars,
                                  NumUniqueDeclarations, NumComponentLists,
                                  NumComponents) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPToClause(unsigned NumVars, unsigned NumUniqueDeclarations,
                       unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(
            OMPC_to, SourceLocation(), SourceLocation(), SourceLocation(),
            NumVars, NumUniqueDeclarations, NumComponentLists, NumComponents) {}

  /// Define the sizes of each trailing object array except the last one. This
  /// is required for TrailingObjects to work properly.
  size_t numTrailingObjects(OverloadToken<Expr *>) const {
    return varlist_size();
  }
  size_t numTrailingObjects(OverloadToken<ValueDecl *>) const {
    return getUniqueDeclarationsNum();
  }
  size_t numTrailingObjects(OverloadToken<unsigned>) const {
    return getUniqueDeclarationsNum() + getTotalComponentListNum();
  }

public:
  /// Creates clause with a list of variables \a Vars.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param Vars The original expression used in the clause.
  /// \param Declarations Declarations used in the clause.
  /// \param ComponentLists Component lists used in the clause.
  static OMPToClause *Create(const ASTContext &C, SourceLocation StartLoc,
                             SourceLocation LParenLoc, SourceLocation EndLoc,
                             ArrayRef<Expr *> Vars,
                             ArrayRef<ValueDecl *> Declarations,
                             MappableExprComponentListsRef ComponentLists);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of unique base declarations in this
  /// clause.
  /// \param NumComponents Total number of expression components in the clause.
  static OMPToClause *CreateEmpty(const ASTContext &C, unsigned NumVars,
                                  unsigned NumUniqueDeclarations,
                                  unsigned NumComponentLists,
                                  unsigned NumComponents);

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_to;
  }
};

/// This represents clause 'from' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp target update from(a,b)
/// \endcode
/// In this example directive '#pragma omp target update' has clause 'from'
/// with the variables 'a' and 'b'.
class OMPFromClause final
    : public OMPMappableExprListClause<OMPFromClause>,
      private llvm::TrailingObjects<
          OMPFromClause, Expr *, ValueDecl *, unsigned,
          OMPClauseMappableExprCommon::MappableComponent> {
  friend class OMPClauseReader;
  friend OMPMappableExprListClause;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPFromClause(SourceLocation StartLoc, SourceLocation LParenLoc,
                         SourceLocation EndLoc, unsigned NumVars,
                         unsigned NumUniqueDeclarations,
                         unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_from, StartLoc, LParenLoc, EndLoc,
                                  NumVars, NumUniqueDeclarations,
                                  NumComponentLists, NumComponents) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPFromClause(unsigned NumVars, unsigned NumUniqueDeclarations,
                         unsigned NumComponentLists, unsigned NumComponents)
      : OMPMappableExprListClause(
            OMPC_from, SourceLocation(), SourceLocation(), SourceLocation(),
            NumVars, NumUniqueDeclarations, NumComponentLists, NumComponents) {}

  /// Define the sizes of each trailing object array except the last one. This
  /// is required for TrailingObjects to work properly.
  size_t numTrailingObjects(OverloadToken<Expr *>) const {
    return varlist_size();
  }
  size_t numTrailingObjects(OverloadToken<ValueDecl *>) const {
    return getUniqueDeclarationsNum();
  }
  size_t numTrailingObjects(OverloadToken<unsigned>) const {
    return getUniqueDeclarationsNum() + getTotalComponentListNum();
  }

public:
  /// Creates clause with a list of variables \a Vars.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param Vars The original expression used in the clause.
  /// \param Declarations Declarations used in the clause.
  /// \param ComponentLists Component lists used in the clause.
  static OMPFromClause *Create(const ASTContext &C, SourceLocation StartLoc,
                               SourceLocation LParenLoc, SourceLocation EndLoc,
                               ArrayRef<Expr *> Vars,
                               ArrayRef<ValueDecl *> Declarations,
                               MappableExprComponentListsRef ComponentLists);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of unique base declarations in this
  /// clause.
  /// \param NumComponents Total number of expression components in the clause.
  static OMPFromClause *CreateEmpty(const ASTContext &C, unsigned NumVars,
                                    unsigned NumUniqueDeclarations,
                                    unsigned NumComponentLists,
                                    unsigned NumComponents);

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_from;
  }
};

/// This represents clause 'use_device_ptr' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp target data use_device_ptr(a,b)
/// \endcode
/// In this example directive '#pragma omp target data' has clause
/// 'use_device_ptr' with the variables 'a' and 'b'.
class OMPUseDevicePtrClause final
    : public OMPMappableExprListClause<OMPUseDevicePtrClause>,
      private llvm::TrailingObjects<
          OMPUseDevicePtrClause, Expr *, ValueDecl *, unsigned,
          OMPClauseMappableExprCommon::MappableComponent> {
  friend class OMPClauseReader;
  friend OMPMappableExprListClause;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPUseDevicePtrClause(SourceLocation StartLoc,
                                 SourceLocation LParenLoc,
                                 SourceLocation EndLoc, unsigned NumVars,
                                 unsigned NumUniqueDeclarations,
                                 unsigned NumComponentLists,
                                 unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_use_device_ptr, StartLoc, LParenLoc,
                                  EndLoc, NumVars, NumUniqueDeclarations,
                                  NumComponentLists, NumComponents) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPUseDevicePtrClause(unsigned NumVars,
                                 unsigned NumUniqueDeclarations,
                                 unsigned NumComponentLists,
                                 unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_use_device_ptr, SourceLocation(),
                                  SourceLocation(), SourceLocation(), NumVars,
                                  NumUniqueDeclarations, NumComponentLists,
                                  NumComponents) {}

  /// Define the sizes of each trailing object array except the last one. This
  /// is required for TrailingObjects to work properly.
  size_t numTrailingObjects(OverloadToken<Expr *>) const {
    return 3 * varlist_size();
  }
  size_t numTrailingObjects(OverloadToken<ValueDecl *>) const {
    return getUniqueDeclarationsNum();
  }
  size_t numTrailingObjects(OverloadToken<unsigned>) const {
    return getUniqueDeclarationsNum() + getTotalComponentListNum();
  }

  /// Sets the list of references to private copies with initializers for new
  /// private variables.
  /// \param VL List of references.
  void setPrivateCopies(ArrayRef<Expr *> VL);

  /// Gets the list of references to private copies with initializers for new
  /// private variables.
  MutableArrayRef<Expr *> getPrivateCopies() {
    return MutableArrayRef<Expr *>(varlist_end(), varlist_size());
  }
  ArrayRef<const Expr *> getPrivateCopies() const {
    return llvm::makeArrayRef(varlist_end(), varlist_size());
  }

  /// Sets the list of references to initializer variables for new private
  /// variables.
  /// \param VL List of references.
  void setInits(ArrayRef<Expr *> VL);

  /// Gets the list of references to initializer variables for new private
  /// variables.
  MutableArrayRef<Expr *> getInits() {
    return MutableArrayRef<Expr *>(getPrivateCopies().end(), varlist_size());
  }
  ArrayRef<const Expr *> getInits() const {
    return llvm::makeArrayRef(getPrivateCopies().end(), varlist_size());
  }

public:
  /// Creates clause with a list of variables \a Vars.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param Vars The original expression used in the clause.
  /// \param PrivateVars Expressions referring to private copies.
  /// \param Inits Expressions referring to private copy initializers.
  /// \param Declarations Declarations used in the clause.
  /// \param ComponentLists Component lists used in the clause.
  static OMPUseDevicePtrClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> Vars,
         ArrayRef<Expr *> PrivateVars, ArrayRef<Expr *> Inits,
         ArrayRef<ValueDecl *> Declarations,
         MappableExprComponentListsRef ComponentLists);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of unique base declarations in this
  /// clause.
  /// \param NumComponents Total number of expression components in the clause.
  static OMPUseDevicePtrClause *CreateEmpty(const ASTContext &C,
                                            unsigned NumVars,
                                            unsigned NumUniqueDeclarations,
                                            unsigned NumComponentLists,
                                            unsigned NumComponents);

  using private_copies_iterator = MutableArrayRef<Expr *>::iterator;
  using private_copies_const_iterator = ArrayRef<const Expr *>::iterator;
  using private_copies_range = llvm::iterator_range<private_copies_iterator>;
  using private_copies_const_range =
      llvm::iterator_range<private_copies_const_iterator>;

  private_copies_range private_copies() {
    return private_copies_range(getPrivateCopies().begin(),
                                getPrivateCopies().end());
  }

  private_copies_const_range private_copies() const {
    return private_copies_const_range(getPrivateCopies().begin(),
                                      getPrivateCopies().end());
  }

  using inits_iterator = MutableArrayRef<Expr *>::iterator;
  using inits_const_iterator = ArrayRef<const Expr *>::iterator;
  using inits_range = llvm::iterator_range<inits_iterator>;
  using inits_const_range = llvm::iterator_range<inits_const_iterator>;

  inits_range inits() {
    return inits_range(getInits().begin(), getInits().end());
  }

  inits_const_range inits() const {
    return inits_const_range(getInits().begin(), getInits().end());
  }

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_use_device_ptr;
  }
};

/// This represents clause 'is_device_ptr' in the '#pragma omp ...'
/// directives.
///
/// \code
/// #pragma omp target is_device_ptr(a,b)
/// \endcode
/// In this example directive '#pragma omp target' has clause
/// 'is_device_ptr' with the variables 'a' and 'b'.
class OMPIsDevicePtrClause final
    : public OMPMappableExprListClause<OMPIsDevicePtrClause>,
      private llvm::TrailingObjects<
          OMPIsDevicePtrClause, Expr *, ValueDecl *, unsigned,
          OMPClauseMappableExprCommon::MappableComponent> {
  friend class OMPClauseReader;
  friend OMPMappableExprListClause;
  friend OMPVarListClause;
  friend TrailingObjects;

  /// Build clause with number of variables \a NumVars.
  ///
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPIsDevicePtrClause(SourceLocation StartLoc,
                                SourceLocation LParenLoc, SourceLocation EndLoc,
                                unsigned NumVars,
                                unsigned NumUniqueDeclarations,
                                unsigned NumComponentLists,
                                unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_is_device_ptr, StartLoc, LParenLoc,
                                  EndLoc, NumVars, NumUniqueDeclarations,
                                  NumComponentLists, NumComponents) {}

  /// Build an empty clause.
  ///
  /// \param NumVars Number of expressions listed in this clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of component lists in this clause.
  /// \param NumComponents Total number of expression components in the clause.
  explicit OMPIsDevicePtrClause(unsigned NumVars,
                                unsigned NumUniqueDeclarations,
                                unsigned NumComponentLists,
                                unsigned NumComponents)
      : OMPMappableExprListClause(OMPC_is_device_ptr, SourceLocation(),
                                  SourceLocation(), SourceLocation(), NumVars,
                                  NumUniqueDeclarations, NumComponentLists,
                                  NumComponents) {}

  /// Define the sizes of each trailing object array except the last one. This
  /// is required for TrailingObjects to work properly.
  size_t numTrailingObjects(OverloadToken<Expr *>) const {
    return varlist_size();
  }
  size_t numTrailingObjects(OverloadToken<ValueDecl *>) const {
    return getUniqueDeclarationsNum();
  }
  size_t numTrailingObjects(OverloadToken<unsigned>) const {
    return getUniqueDeclarationsNum() + getTotalComponentListNum();
  }

public:
  /// Creates clause with a list of variables \a Vars.
  ///
  /// \param C AST context.
  /// \param StartLoc Starting location of the clause.
  /// \param EndLoc Ending location of the clause.
  /// \param Vars The original expression used in the clause.
  /// \param Declarations Declarations used in the clause.
  /// \param ComponentLists Component lists used in the clause.
  static OMPIsDevicePtrClause *
  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
         SourceLocation EndLoc, ArrayRef<Expr *> Vars,
         ArrayRef<ValueDecl *> Declarations,
         MappableExprComponentListsRef ComponentLists);

  /// Creates an empty clause with the place for \a NumVars variables.
  ///
  /// \param C AST context.
  /// \param NumVars Number of expressions listed in the clause.
  /// \param NumUniqueDeclarations Number of unique base declarations in this
  /// clause.
  /// \param NumComponentLists Number of unique base declarations in this
  /// clause.
  /// \param NumComponents Total number of expression components in the clause.
  static OMPIsDevicePtrClause *CreateEmpty(const ASTContext &C,
                                           unsigned NumVars,
                                           unsigned NumUniqueDeclarations,
                                           unsigned NumComponentLists,
                                           unsigned NumComponents);

  child_range children() {
    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
                       reinterpret_cast<Stmt **>(varlist_end()));
  }

  static bool classof(const OMPClause *T) {
    return T->getClauseKind() == OMPC_is_device_ptr;
  }
};

/// This class implements a simple visitor for OMPClause
/// subclasses.
template<class ImplClass, template <typename> class Ptr, typename RetTy>
class OMPClauseVisitorBase {
public:
#define PTR(CLASS) typename Ptr<CLASS>::type
#define DISPATCH(CLASS) \
  return static_cast<ImplClass*>(this)->Visit##CLASS(static_cast<PTR(CLASS)>(S))

#define OPENMP_CLAUSE(Name, Class)                              \
  RetTy Visit ## Class (PTR(Class) S) { DISPATCH(Class); }
#include "clang/Basic/OpenMPKinds.def"

  RetTy Visit(PTR(OMPClause) S) {
    // Top switch clause: visit each OMPClause.
    switch (S->getClauseKind()) {
    default: llvm_unreachable("Unknown clause kind!");
#define OPENMP_CLAUSE(Name, Class)                              \
    case OMPC_ ## Name : return Visit ## Class(static_cast<PTR(Class)>(S));
#include "clang/Basic/OpenMPKinds.def"
    }
  }
  // Base case, ignore it. :)
  RetTy VisitOMPClause(PTR(OMPClause) Node) { return RetTy(); }
#undef PTR
#undef DISPATCH
};

template <typename T>
using const_ptr = typename std::add_pointer<typename std::add_const<T>::type>;

template<class ImplClass, typename RetTy = void>
class OMPClauseVisitor :
      public OMPClauseVisitorBase <ImplClass, std::add_pointer, RetTy> {};
template<class ImplClass, typename RetTy = void>
class ConstOMPClauseVisitor :
      public OMPClauseVisitorBase <ImplClass, const_ptr, RetTy> {};
} // namespace clang

#endif // LLVM_CLANG_AST_OPENMPCLAUSE_H