clang/lib/Parse/ParseOpenMP.cpp

//===--- ParseOpenMP.cpp - OpenMP directives parsing ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements parsing of all OpenMP directives and clauses.
///
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTContext.h"
#include "clang/AST/OpenMPClause.h"
#include "clang/AST/StmtOpenMP.h"
#include "clang/Basic/OpenMPKinds.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Parse/Parser.h"
#include "clang/Parse/RAIIObjectsForParser.h"
#include "clang/Sema/Scope.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/UniqueVector.h"
#include "llvm/Frontend/OpenMP/OMPContext.h"

using namespace clang;
using namespace llvm::omp;

//===----------------------------------------------------------------------===//
// OpenMP declarative directives.
//===----------------------------------------------------------------------===//

namespace {
enum OpenMPDirectiveKindEx {
  OMPD_cancellation = llvm::omp::Directive_enumSize + 1,
  OMPD_data,
  OMPD_declare,
  OMPD_end,
  OMPD_end_declare,
  OMPD_enter,
  OMPD_exit,
  OMPD_point,
  OMPD_reduction,
  OMPD_target_enter,
  OMPD_target_exit,
  OMPD_update,
  OMPD_distribute_parallel,
  OMPD_teams_distribute_parallel,
  OMPD_target_teams_distribute_parallel,
  OMPD_mapper,
  OMPD_variant,
  OMPD_begin,
  OMPD_begin_declare,
};

// Helper to unify the enum class OpenMPDirectiveKind with its extension
// the OpenMPDirectiveKindEx enum which allows to use them together as if they
// are unsigned values.
struct OpenMPDirectiveKindExWrapper {
  OpenMPDirectiveKindExWrapper(unsigned Value) : Value(Value) {}
  OpenMPDirectiveKindExWrapper(OpenMPDirectiveKind DK) : Value(unsigned(DK)) {}
  bool operator==(OpenMPDirectiveKind V) const { return Value == unsigned(V); }
  bool operator!=(OpenMPDirectiveKind V) const { return Value != unsigned(V); }
  bool operator<(OpenMPDirectiveKind V) const { return Value < unsigned(V); }
  operator unsigned() const { return Value; }
  operator OpenMPDirectiveKind() const { return OpenMPDirectiveKind(Value); }
  unsigned Value;
};

class DeclDirectiveListParserHelper final {
  SmallVector<Expr *, 4> Identifiers;
  Parser *P;
  OpenMPDirectiveKind Kind;

public:
  DeclDirectiveListParserHelper(Parser *P, OpenMPDirectiveKind Kind)
      : P(P), Kind(Kind) {}
  void operator()(CXXScopeSpec &SS, DeclarationNameInfo NameInfo) {
    ExprResult Res = P->getActions().ActOnOpenMPIdExpression(
        P->getCurScope(), SS, NameInfo, Kind);
    if (Res.isUsable())
      Identifiers.push_back(Res.get());
  }
  llvm::ArrayRef<Expr *> getIdentifiers() const { return Identifiers; }
};
} // namespace

// Map token string to extended OMP token kind that are
// OpenMPDirectiveKind + OpenMPDirectiveKindEx.
static unsigned getOpenMPDirectiveKindEx(StringRef S) {
  OpenMPDirectiveKindExWrapper DKind = getOpenMPDirectiveKind(S);
  if (DKind != OMPD_unknown)
    return DKind;

  return llvm::StringSwitch<OpenMPDirectiveKindExWrapper>(S)
      .Case("cancellation", OMPD_cancellation)
      .Case("data", OMPD_data)
      .Case("declare", OMPD_declare)
      .Case("end", OMPD_end)
      .Case("enter", OMPD_enter)
      .Case("exit", OMPD_exit)
      .Case("point", OMPD_point)
      .Case("reduction", OMPD_reduction)
      .Case("update", OMPD_update)
      .Case("mapper", OMPD_mapper)
      .Case("variant", OMPD_variant)
      .Case("begin", OMPD_begin)
      .Default(OMPD_unknown);
}

static OpenMPDirectiveKindExWrapper parseOpenMPDirectiveKind(Parser &P) {
  // Array of foldings: F[i][0] F[i][1] ===> F[i][2].
  // E.g.: OMPD_for OMPD_simd ===> OMPD_for_simd
  // TODO: add other combined directives in topological order.
  static const OpenMPDirectiveKindExWrapper F[][3] = {
      {OMPD_begin, OMPD_declare, OMPD_begin_declare},
      {OMPD_end, OMPD_declare, OMPD_end_declare},
      {OMPD_cancellation, OMPD_point, OMPD_cancellation_point},
      {OMPD_declare, OMPD_reduction, OMPD_declare_reduction},
      {OMPD_declare, OMPD_mapper, OMPD_declare_mapper},
      {OMPD_declare, OMPD_simd, OMPD_declare_simd},
      {OMPD_declare, OMPD_target, OMPD_declare_target},
      {OMPD_declare, OMPD_variant, OMPD_declare_variant},
      {OMPD_begin_declare, OMPD_variant, OMPD_begin_declare_variant},
      {OMPD_end_declare, OMPD_variant, OMPD_end_declare_variant},
      {OMPD_distribute, OMPD_parallel, OMPD_distribute_parallel},
      {OMPD_distribute_parallel, OMPD_for, OMPD_distribute_parallel_for},
      {OMPD_distribute_parallel_for, OMPD_simd,
       OMPD_distribute_parallel_for_simd},
      {OMPD_distribute, OMPD_simd, OMPD_distribute_simd},
      {OMPD_end_declare, OMPD_target, OMPD_end_declare_target},
      {OMPD_target, OMPD_data, OMPD_target_data},
      {OMPD_target, OMPD_enter, OMPD_target_enter},
      {OMPD_target, OMPD_exit, OMPD_target_exit},
      {OMPD_target, OMPD_update, OMPD_target_update},
      {OMPD_target_enter, OMPD_data, OMPD_target_enter_data},
      {OMPD_target_exit, OMPD_data, OMPD_target_exit_data},
      {OMPD_for, OMPD_simd, OMPD_for_simd},
      {OMPD_parallel, OMPD_for, OMPD_parallel_for},
      {OMPD_parallel_for, OMPD_simd, OMPD_parallel_for_simd},
      {OMPD_parallel, OMPD_sections, OMPD_parallel_sections},
      {OMPD_taskloop, OMPD_simd, OMPD_taskloop_simd},
      {OMPD_target, OMPD_parallel, OMPD_target_parallel},
      {OMPD_target, OMPD_simd, OMPD_target_simd},
      {OMPD_target_parallel, OMPD_for, OMPD_target_parallel_for},
      {OMPD_target_parallel_for, OMPD_simd, OMPD_target_parallel_for_simd},
      {OMPD_teams, OMPD_distribute, OMPD_teams_distribute},
      {OMPD_teams_distribute, OMPD_simd, OMPD_teams_distribute_simd},
      {OMPD_teams_distribute, OMPD_parallel, OMPD_teams_distribute_parallel},
      {OMPD_teams_distribute_parallel, OMPD_for,
       OMPD_teams_distribute_parallel_for},
      {OMPD_teams_distribute_parallel_for, OMPD_simd,
       OMPD_teams_distribute_parallel_for_simd},
      {OMPD_target, OMPD_teams, OMPD_target_teams},
      {OMPD_target_teams, OMPD_distribute, OMPD_target_teams_distribute},
      {OMPD_target_teams_distribute, OMPD_parallel,
       OMPD_target_teams_distribute_parallel},
      {OMPD_target_teams_distribute, OMPD_simd,
       OMPD_target_teams_distribute_simd},
      {OMPD_target_teams_distribute_parallel, OMPD_for,
       OMPD_target_teams_distribute_parallel_for},
      {OMPD_target_teams_distribute_parallel_for, OMPD_simd,
       OMPD_target_teams_distribute_parallel_for_simd},
      {OMPD_master, OMPD_taskloop, OMPD_master_taskloop},
      {OMPD_master_taskloop, OMPD_simd, OMPD_master_taskloop_simd},
      {OMPD_parallel, OMPD_master, OMPD_parallel_master},
      {OMPD_parallel_master, OMPD_taskloop, OMPD_parallel_master_taskloop},
      {OMPD_parallel_master_taskloop, OMPD_simd,
       OMPD_parallel_master_taskloop_simd}};
  enum { CancellationPoint = 0, DeclareReduction = 1, TargetData = 2 };
  Token Tok = P.getCurToken();
  OpenMPDirectiveKindExWrapper DKind =
      Tok.isAnnotation()
          ? static_cast<unsigned>(OMPD_unknown)
          : getOpenMPDirectiveKindEx(P.getPreprocessor().getSpelling(Tok));
  if (DKind == OMPD_unknown)
    return OMPD_unknown;

  for (unsigned I = 0; I < llvm::array_lengthof(F); ++I) {
    if (DKind != F[I][0])
      continue;

    Tok = P.getPreprocessor().LookAhead(0);
    OpenMPDirectiveKindExWrapper SDKind =
        Tok.isAnnotation()
            ? static_cast<unsigned>(OMPD_unknown)
            : getOpenMPDirectiveKindEx(P.getPreprocessor().getSpelling(Tok));
    if (SDKind == OMPD_unknown)
      continue;

    if (SDKind == F[I][1]) {
      P.ConsumeToken();
      DKind = F[I][2];
    }
  }
  return unsigned(DKind) < llvm::omp::Directive_enumSize
             ? static_cast<OpenMPDirectiveKind>(DKind)
             : OMPD_unknown;
}

static DeclarationName parseOpenMPReductionId(Parser &P) {
  Token Tok = P.getCurToken();
  Sema &Actions = P.getActions();
  OverloadedOperatorKind OOK = OO_None;
  // Allow to use 'operator' keyword for C++ operators
  bool WithOperator = false;
  if (Tok.is(tok::kw_operator)) {
    P.ConsumeToken();
    Tok = P.getCurToken();
    WithOperator = true;
  }
  switch (Tok.getKind()) {
  case tok::plus: // '+'
    OOK = OO_Plus;
    break;
  case tok::minus: // '-'
    OOK = OO_Minus;
    break;
  case tok::star: // '*'
    OOK = OO_Star;
    break;
  case tok::amp: // '&'
    OOK = OO_Amp;
    break;
  case tok::pipe: // '|'
    OOK = OO_Pipe;
    break;
  case tok::caret: // '^'
    OOK = OO_Caret;
    break;
  case tok::ampamp: // '&&'
    OOK = OO_AmpAmp;
    break;
  case tok::pipepipe: // '||'
    OOK = OO_PipePipe;
    break;
  case tok::identifier: // identifier
    if (!WithOperator)
      break;
    LLVM_FALLTHROUGH;
  default:
    P.Diag(Tok.getLocation(), diag::err_omp_expected_reduction_identifier);
    P.SkipUntil(tok::colon, tok::r_paren, tok::annot_pragma_openmp_end,
                Parser::StopBeforeMatch);
    return DeclarationName();
  }
  P.ConsumeToken();
  auto &DeclNames = Actions.getASTContext().DeclarationNames;
  return OOK == OO_None ? DeclNames.getIdentifier(Tok.getIdentifierInfo())
                        : DeclNames.getCXXOperatorName(OOK);
}

/// Parse 'omp declare reduction' construct.
///
///       declare-reduction-directive:
///        annot_pragma_openmp 'declare' 'reduction'
///        '(' <reduction_id> ':' <type> {',' <type>} ':' <expression> ')'
///        ['initializer' '(' ('omp_priv' '=' <expression>)|<function_call> ')']
///        annot_pragma_openmp_end
/// <reduction_id> is either a base language identifier or one of the following
/// operators: '+', '-', '*', '&', '|', '^', '&&' and '||'.
///
Parser::DeclGroupPtrTy
Parser::ParseOpenMPDeclareReductionDirective(AccessSpecifier AS) {
  // Parse '('.
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(
          diag::err_expected_lparen_after,
          getOpenMPDirectiveName(OMPD_declare_reduction).data())) {
    SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
    return DeclGroupPtrTy();
  }

  DeclarationName Name = parseOpenMPReductionId(*this);
  if (Name.isEmpty() && Tok.is(tok::annot_pragma_openmp_end))
    return DeclGroupPtrTy();

  // Consume ':'.
  bool IsCorrect = !ExpectAndConsume(tok::colon);

  if (!IsCorrect && Tok.is(tok::annot_pragma_openmp_end))
    return DeclGroupPtrTy();

  IsCorrect = IsCorrect && !Name.isEmpty();

  if (Tok.is(tok::colon) || Tok.is(tok::annot_pragma_openmp_end)) {
    Diag(Tok.getLocation(), diag::err_expected_type);
    IsCorrect = false;
  }

  if (!IsCorrect && Tok.is(tok::annot_pragma_openmp_end))
    return DeclGroupPtrTy();

  SmallVector<std::pair<QualType, SourceLocation>, 8> ReductionTypes;
  // Parse list of types until ':' token.
  do {
    ColonProtectionRAIIObject ColonRAII(*this);
    SourceRange Range;
    TypeResult TR =
        ParseTypeName(&Range, DeclaratorContext::PrototypeContext, AS);
    if (TR.isUsable()) {
      QualType ReductionType =
          Actions.ActOnOpenMPDeclareReductionType(Range.getBegin(), TR);
      if (!ReductionType.isNull()) {
        ReductionTypes.push_back(
            std::make_pair(ReductionType, Range.getBegin()));
      }
    } else {
      SkipUntil(tok::comma, tok::colon, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
    }

    if (Tok.is(tok::colon) || Tok.is(tok::annot_pragma_openmp_end))
      break;

    // Consume ','.
    if (ExpectAndConsume(tok::comma)) {
      IsCorrect = false;
      if (Tok.is(tok::annot_pragma_openmp_end)) {
        Diag(Tok.getLocation(), diag::err_expected_type);
        return DeclGroupPtrTy();
      }
    }
  } while (Tok.isNot(tok::annot_pragma_openmp_end));

  if (ReductionTypes.empty()) {
    SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
    return DeclGroupPtrTy();
  }

  if (!IsCorrect && Tok.is(tok::annot_pragma_openmp_end))
    return DeclGroupPtrTy();

  // Consume ':'.
  if (ExpectAndConsume(tok::colon))
    IsCorrect = false;

  if (Tok.is(tok::annot_pragma_openmp_end)) {
    Diag(Tok.getLocation(), diag::err_expected_expression);
    return DeclGroupPtrTy();
  }

  DeclGroupPtrTy DRD = Actions.ActOnOpenMPDeclareReductionDirectiveStart(
      getCurScope(), Actions.getCurLexicalContext(), Name, ReductionTypes, AS);

  // Parse <combiner> expression and then parse initializer if any for each
  // correct type.
  unsigned I = 0, E = ReductionTypes.size();
  for (Decl *D : DRD.get()) {
    TentativeParsingAction TPA(*this);
    ParseScope OMPDRScope(this, Scope::FnScope | Scope::DeclScope |
                                    Scope::CompoundStmtScope |
                                    Scope::OpenMPDirectiveScope);
    // Parse <combiner> expression.
    Actions.ActOnOpenMPDeclareReductionCombinerStart(getCurScope(), D);
    ExprResult CombinerResult = Actions.ActOnFinishFullExpr(
        ParseExpression().get(), D->getLocation(), /*DiscardedValue*/ false);
    Actions.ActOnOpenMPDeclareReductionCombinerEnd(D, CombinerResult.get());

    if (CombinerResult.isInvalid() && Tok.isNot(tok::r_paren) &&
        Tok.isNot(tok::annot_pragma_openmp_end)) {
      TPA.Commit();
      IsCorrect = false;
      break;
    }
    IsCorrect = !T.consumeClose() && IsCorrect && CombinerResult.isUsable();
    ExprResult InitializerResult;
    if (Tok.isNot(tok::annot_pragma_openmp_end)) {
      // Parse <initializer> expression.
      if (Tok.is(tok::identifier) &&
          Tok.getIdentifierInfo()->isStr("initializer")) {
        ConsumeToken();
      } else {
        Diag(Tok.getLocation(), diag::err_expected) << "'initializer'";
        TPA.Commit();
        IsCorrect = false;
        break;
      }
      // Parse '('.
      BalancedDelimiterTracker T(*this, tok::l_paren,
                                 tok::annot_pragma_openmp_end);
      IsCorrect =
          !T.expectAndConsume(diag::err_expected_lparen_after, "initializer") &&
          IsCorrect;
      if (Tok.isNot(tok::annot_pragma_openmp_end)) {
        ParseScope OMPDRScope(this, Scope::FnScope | Scope::DeclScope |
                                        Scope::CompoundStmtScope |
                                        Scope::OpenMPDirectiveScope);
        // Parse expression.
        VarDecl *OmpPrivParm =
            Actions.ActOnOpenMPDeclareReductionInitializerStart(getCurScope(),
                                                                D);
        // Check if initializer is omp_priv <init_expr> or something else.
        if (Tok.is(tok::identifier) &&
            Tok.getIdentifierInfo()->isStr("omp_priv")) {
          ConsumeToken();
          ParseOpenMPReductionInitializerForDecl(OmpPrivParm);
        } else {
          InitializerResult = Actions.ActOnFinishFullExpr(
              ParseAssignmentExpression().get(), D->getLocation(),
              /*DiscardedValue*/ false);
        }
        Actions.ActOnOpenMPDeclareReductionInitializerEnd(
            D, InitializerResult.get(), OmpPrivParm);
        if (InitializerResult.isInvalid() && Tok.isNot(tok::r_paren) &&
            Tok.isNot(tok::annot_pragma_openmp_end)) {
          TPA.Commit();
          IsCorrect = false;
          break;
        }
        IsCorrect =
            !T.consumeClose() && IsCorrect && !InitializerResult.isInvalid();
      }
    }

    ++I;
    // Revert parsing if not the last type, otherwise accept it, we're done with
    // parsing.
    if (I != E)
      TPA.Revert();
    else
      TPA.Commit();
  }
  return Actions.ActOnOpenMPDeclareReductionDirectiveEnd(getCurScope(), DRD,
                                                         IsCorrect);
}

void Parser::ParseOpenMPReductionInitializerForDecl(VarDecl *OmpPrivParm) {
  // Parse declarator '=' initializer.
  // If a '==' or '+=' is found, suggest a fixit to '='.
  if (isTokenEqualOrEqualTypo()) {
    ConsumeToken();

    if (Tok.is(tok::code_completion)) {
      Actions.CodeCompleteInitializer(getCurScope(), OmpPrivParm);
      Actions.FinalizeDeclaration(OmpPrivParm);
      cutOffParsing();
      return;
    }

    PreferredType.enterVariableInit(Tok.getLocation(), OmpPrivParm);
    ExprResult Init = ParseInitializer();

    if (Init.isInvalid()) {
      SkipUntil(tok::r_paren, tok::annot_pragma_openmp_end, StopBeforeMatch);
      Actions.ActOnInitializerError(OmpPrivParm);
    } else {
      Actions.AddInitializerToDecl(OmpPrivParm, Init.get(),
                                   /*DirectInit=*/false);
    }
  } else if (Tok.is(tok::l_paren)) {
    // Parse C++ direct initializer: '(' expression-list ')'
    BalancedDelimiterTracker T(*this, tok::l_paren);
    T.consumeOpen();

    ExprVector Exprs;
    CommaLocsTy CommaLocs;

    SourceLocation LParLoc = T.getOpenLocation();
    auto RunSignatureHelp = [this, OmpPrivParm, LParLoc, &Exprs]() {
      QualType PreferredType = Actions.ProduceConstructorSignatureHelp(
          getCurScope(), OmpPrivParm->getType()->getCanonicalTypeInternal(),
          OmpPrivParm->getLocation(), Exprs, LParLoc);
      CalledSignatureHelp = true;
      return PreferredType;
    };
    if (ParseExpressionList(Exprs, CommaLocs, [&] {
          PreferredType.enterFunctionArgument(Tok.getLocation(),
                                              RunSignatureHelp);
        })) {
      if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
        RunSignatureHelp();
      Actions.ActOnInitializerError(OmpPrivParm);
      SkipUntil(tok::r_paren, tok::annot_pragma_openmp_end, StopBeforeMatch);
    } else {
      // Match the ')'.
      SourceLocation RLoc = Tok.getLocation();
      if (!T.consumeClose())
        RLoc = T.getCloseLocation();

      assert(!Exprs.empty() && Exprs.size() - 1 == CommaLocs.size() &&
             "Unexpected number of commas!");

      ExprResult Initializer =
          Actions.ActOnParenListExpr(T.getOpenLocation(), RLoc, Exprs);
      Actions.AddInitializerToDecl(OmpPrivParm, Initializer.get(),
                                   /*DirectInit=*/true);
    }
  } else if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
    // Parse C++0x braced-init-list.
    Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);

    ExprResult Init(ParseBraceInitializer());

    if (Init.isInvalid()) {
      Actions.ActOnInitializerError(OmpPrivParm);
    } else {
      Actions.AddInitializerToDecl(OmpPrivParm, Init.get(),
                                   /*DirectInit=*/true);
    }
  } else {
    Actions.ActOnUninitializedDecl(OmpPrivParm);
  }
}

/// Parses 'omp declare mapper' directive.
///
///       declare-mapper-directive:
///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifier> ':']
///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
///         annot_pragma_openmp_end
/// <mapper-identifier> and <var> are base language identifiers.
///
Parser::DeclGroupPtrTy
Parser::ParseOpenMPDeclareMapperDirective(AccessSpecifier AS) {
  bool IsCorrect = true;
  // Parse '('
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after,
                         getOpenMPDirectiveName(OMPD_declare_mapper).data())) {
    SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
    return DeclGroupPtrTy();
  }

  // Parse <mapper-identifier>
  auto &DeclNames = Actions.getASTContext().DeclarationNames;
  DeclarationName MapperId;
  if (PP.LookAhead(0).is(tok::colon)) {
    if (Tok.isNot(tok::identifier) && Tok.isNot(tok::kw_default)) {
      Diag(Tok.getLocation(), diag::err_omp_mapper_illegal_identifier);
      IsCorrect = false;
    } else {
      MapperId = DeclNames.getIdentifier(Tok.getIdentifierInfo());
    }
    ConsumeToken();
    // Consume ':'.
    ExpectAndConsume(tok::colon);
  } else {
    // If no mapper identifier is provided, its name is "default" by default
    MapperId =
        DeclNames.getIdentifier(&Actions.getASTContext().Idents.get("default"));
  }

  if (!IsCorrect && Tok.is(tok::annot_pragma_openmp_end))
    return DeclGroupPtrTy();

  // Parse <type> <var>
  DeclarationName VName;
  QualType MapperType;
  SourceRange Range;
  TypeResult ParsedType = parseOpenMPDeclareMapperVarDecl(Range, VName, AS);
  if (ParsedType.isUsable())
    MapperType =
        Actions.ActOnOpenMPDeclareMapperType(Range.getBegin(), ParsedType);
  if (MapperType.isNull())
    IsCorrect = false;
  if (!IsCorrect) {
    SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch);
    return DeclGroupPtrTy();
  }

  // Consume ')'.
  IsCorrect &= !T.consumeClose();
  if (!IsCorrect) {
    SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch);
    return DeclGroupPtrTy();
  }

  // Enter scope.
  DeclarationNameInfo DirName;
  SourceLocation Loc = Tok.getLocation();
  unsigned ScopeFlags = Scope::FnScope | Scope::DeclScope |
                        Scope::CompoundStmtScope | Scope::OpenMPDirectiveScope;
  ParseScope OMPDirectiveScope(this, ScopeFlags);
  Actions.StartOpenMPDSABlock(OMPD_declare_mapper, DirName, getCurScope(), Loc);

  // Add the mapper variable declaration.
  ExprResult MapperVarRef = Actions.ActOnOpenMPDeclareMapperDirectiveVarDecl(
      getCurScope(), MapperType, Range.getBegin(), VName);

  // Parse map clauses.
  SmallVector<OMPClause *, 6> Clauses;
  while (Tok.isNot(tok::annot_pragma_openmp_end)) {
    OpenMPClauseKind CKind = Tok.isAnnotation()
                                 ? OMPC_unknown
                                 : getOpenMPClauseKind(PP.getSpelling(Tok));
    Actions.StartOpenMPClause(CKind);
    OMPClause *Clause =
        ParseOpenMPClause(OMPD_declare_mapper, CKind, Clauses.empty());
    if (Clause)
      Clauses.push_back(Clause);
    else
      IsCorrect = false;
    // Skip ',' if any.
    if (Tok.is(tok::comma))
      ConsumeToken();
    Actions.EndOpenMPClause();
  }
  if (Clauses.empty()) {
    Diag(Tok, diag::err_omp_expected_clause)
        << getOpenMPDirectiveName(OMPD_declare_mapper);
    IsCorrect = false;
  }

  // Exit scope.
  Actions.EndOpenMPDSABlock(nullptr);
  OMPDirectiveScope.Exit();
  DeclGroupPtrTy DG = Actions.ActOnOpenMPDeclareMapperDirective(
      getCurScope(), Actions.getCurLexicalContext(), MapperId, MapperType,
      Range.getBegin(), VName, AS, MapperVarRef.get(), Clauses);
  if (!IsCorrect)
    return DeclGroupPtrTy();

  return DG;
}

TypeResult Parser::parseOpenMPDeclareMapperVarDecl(SourceRange &Range,
                                                   DeclarationName &Name,
                                                   AccessSpecifier AS) {
  // Parse the common declaration-specifiers piece.
  Parser::DeclSpecContext DSC = Parser::DeclSpecContext::DSC_type_specifier;
  DeclSpec DS(AttrFactory);
  ParseSpecifierQualifierList(DS, AS, DSC);

  // Parse the declarator.
  DeclaratorContext Context = DeclaratorContext::PrototypeContext;
  Declarator DeclaratorInfo(DS, Context);
  ParseDeclarator(DeclaratorInfo);
  Range = DeclaratorInfo.getSourceRange();
  if (DeclaratorInfo.getIdentifier() == nullptr) {
    Diag(Tok.getLocation(), diag::err_omp_mapper_expected_declarator);
    return true;
  }
  Name = Actions.GetNameForDeclarator(DeclaratorInfo).getName();

  return Actions.ActOnOpenMPDeclareMapperVarDecl(getCurScope(), DeclaratorInfo);
}

namespace {
/// RAII that recreates function context for correct parsing of clauses of
/// 'declare simd' construct.
/// OpenMP, 2.8.2 declare simd Construct
/// The expressions appearing in the clauses of this directive are evaluated in
/// the scope of the arguments of the function declaration or definition.
class FNContextRAII final {
  Parser &P;
  Sema::CXXThisScopeRAII *ThisScope;
  Parser::MultiParseScope Scopes;
  bool HasFunScope = false;
  FNContextRAII() = delete;
  FNContextRAII(const FNContextRAII &) = delete;
  FNContextRAII &operator=(const FNContextRAII &) = delete;

public:
  FNContextRAII(Parser &P, Parser::DeclGroupPtrTy Ptr) : P(P), Scopes(P) {
    Decl *D = *Ptr.get().begin();
    NamedDecl *ND = dyn_cast<NamedDecl>(D);
    RecordDecl *RD = dyn_cast_or_null<RecordDecl>(D->getDeclContext());
    Sema &Actions = P.getActions();

    // Allow 'this' within late-parsed attributes.
    ThisScope = new Sema::CXXThisScopeRAII(Actions, RD, Qualifiers(),
                                           ND && ND->isCXXInstanceMember());

    // If the Decl is templatized, add template parameters to scope.
    // FIXME: Track CurTemplateDepth?
    P.ReenterTemplateScopes(Scopes, D);

    // If the Decl is on a function, add function parameters to the scope.
    if (D->isFunctionOrFunctionTemplate()) {
      HasFunScope = true;
      Scopes.Enter(Scope::FnScope | Scope::DeclScope |
                   Scope::CompoundStmtScope);
      Actions.ActOnReenterFunctionContext(Actions.getCurScope(), D);
    }
  }
  ~FNContextRAII() {
    if (HasFunScope)
      P.getActions().ActOnExitFunctionContext();
    delete ThisScope;
  }
};
} // namespace

/// Parses clauses for 'declare simd' directive.
///    clause:
///      'inbranch' | 'notinbranch'
///      'simdlen' '(' <expr> ')'
///      { 'uniform' '(' <argument_list> ')' }
///      { 'aligned '(' <argument_list> [ ':' <alignment> ] ')' }
///      { 'linear '(' <argument_list> [ ':' <step> ] ')' }
static bool parseDeclareSimdClauses(
    Parser &P, OMPDeclareSimdDeclAttr::BranchStateTy &BS, ExprResult &SimdLen,
    SmallVectorImpl<Expr *> &Uniforms, SmallVectorImpl<Expr *> &Aligneds,
    SmallVectorImpl<Expr *> &Alignments, SmallVectorImpl<Expr *> &Linears,
    SmallVectorImpl<unsigned> &LinModifiers, SmallVectorImpl<Expr *> &Steps) {
  SourceRange BSRange;
  const Token &Tok = P.getCurToken();
  bool IsError = false;
  while (Tok.isNot(tok::annot_pragma_openmp_end)) {
    if (Tok.isNot(tok::identifier))
      break;
    OMPDeclareSimdDeclAttr::BranchStateTy Out;
    IdentifierInfo *II = Tok.getIdentifierInfo();
    StringRef ClauseName = II->getName();
    // Parse 'inranch|notinbranch' clauses.
    if (OMPDeclareSimdDeclAttr::ConvertStrToBranchStateTy(ClauseName, Out)) {
      if (BS != OMPDeclareSimdDeclAttr::BS_Undefined && BS != Out) {
        P.Diag(Tok, diag::err_omp_declare_simd_inbranch_notinbranch)
            << ClauseName
            << OMPDeclareSimdDeclAttr::ConvertBranchStateTyToStr(BS) << BSRange;
        IsError = true;
      }
      BS = Out;
      BSRange = SourceRange(Tok.getLocation(), Tok.getEndLoc());
      P.ConsumeToken();
    } else if (ClauseName.equals("simdlen")) {
      if (SimdLen.isUsable()) {
        P.Diag(Tok, diag::err_omp_more_one_clause)
            << getOpenMPDirectiveName(OMPD_declare_simd) << ClauseName << 0;
        IsError = true;
      }
      P.ConsumeToken();
      SourceLocation RLoc;
      SimdLen = P.ParseOpenMPParensExpr(ClauseName, RLoc);
      if (SimdLen.isInvalid())
        IsError = true;
    } else {
      OpenMPClauseKind CKind = getOpenMPClauseKind(ClauseName);
      if (CKind == OMPC_uniform || CKind == OMPC_aligned ||
          CKind == OMPC_linear) {
        Parser::OpenMPVarListDataTy Data;
        SmallVectorImpl<Expr *> *Vars = &Uniforms;
        if (CKind == OMPC_aligned) {
          Vars = &Aligneds;
        } else if (CKind == OMPC_linear) {
          Data.ExtraModifier = OMPC_LINEAR_val;
          Vars = &Linears;
        }

        P.ConsumeToken();
        if (P.ParseOpenMPVarList(OMPD_declare_simd,
                                 getOpenMPClauseKind(ClauseName), *Vars, Data))
          IsError = true;
        if (CKind == OMPC_aligned) {
          Alignments.append(Aligneds.size() - Alignments.size(),
                            Data.DepModOrTailExpr);
        } else if (CKind == OMPC_linear) {
          assert(0 <= Data.ExtraModifier &&
                 Data.ExtraModifier <= OMPC_LINEAR_unknown &&
                 "Unexpected linear modifier.");
          if (P.getActions().CheckOpenMPLinearModifier(
                  static_cast<OpenMPLinearClauseKind>(Data.ExtraModifier),
                  Data.ExtraModifierLoc))
            Data.ExtraModifier = OMPC_LINEAR_val;
          LinModifiers.append(Linears.size() - LinModifiers.size(),
                              Data.ExtraModifier);
          Steps.append(Linears.size() - Steps.size(), Data.DepModOrTailExpr);
        }
      } else
        // TODO: add parsing of other clauses.
        break;
    }
    // Skip ',' if any.
    if (Tok.is(tok::comma))
      P.ConsumeToken();
  }
  return IsError;
}

/// Parse clauses for '#pragma omp declare simd'.
Parser::DeclGroupPtrTy
Parser::ParseOMPDeclareSimdClauses(Parser::DeclGroupPtrTy Ptr,
                                   CachedTokens &Toks, SourceLocation Loc) {
  PP.EnterToken(Tok, /*IsReinject*/ true);
  PP.EnterTokenStream(Toks, /*DisableMacroExpansion=*/true,
                      /*IsReinject*/ true);
  // Consume the previously pushed token.
  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);

  FNContextRAII FnContext(*this, Ptr);
  OMPDeclareSimdDeclAttr::BranchStateTy BS =
      OMPDeclareSimdDeclAttr::BS_Undefined;
  ExprResult Simdlen;
  SmallVector<Expr *, 4> Uniforms;
  SmallVector<Expr *, 4> Aligneds;
  SmallVector<Expr *, 4> Alignments;
  SmallVector<Expr *, 4> Linears;
  SmallVector<unsigned, 4> LinModifiers;
  SmallVector<Expr *, 4> Steps;
  bool IsError =
      parseDeclareSimdClauses(*this, BS, Simdlen, Uniforms, Aligneds,
                              Alignments, Linears, LinModifiers, Steps);
  skipUntilPragmaOpenMPEnd(OMPD_declare_simd);
  // Skip the last annot_pragma_openmp_end.
  SourceLocation EndLoc = ConsumeAnnotationToken();
  if (IsError)
    return Ptr;
  return Actions.ActOnOpenMPDeclareSimdDirective(
      Ptr, BS, Simdlen.get(), Uniforms, Aligneds, Alignments, Linears,
      LinModifiers, Steps, SourceRange(Loc, EndLoc));
}

namespace {
/// Constant used in the diagnostics to distinguish the levels in an OpenMP
/// contexts: selector-set={selector(trait, ...), ...}, ....
enum OMPContextLvl {
  CONTEXT_SELECTOR_SET_LVL = 0,
  CONTEXT_SELECTOR_LVL = 1,
  CONTEXT_TRAIT_LVL = 2,
};

static StringRef stringLiteralParser(Parser &P) {
  ExprResult Res = P.ParseStringLiteralExpression(true);
  return Res.isUsable() ? Res.getAs<StringLiteral>()->getString() : "";
}

static StringRef getNameFromIdOrString(Parser &P, Token &Tok,
                                       OMPContextLvl Lvl) {
  if (Tok.is(tok::identifier)) {
    llvm::SmallString<16> Buffer;
    StringRef Name = P.getPreprocessor().getSpelling(Tok, Buffer);
    (void)P.ConsumeToken();
    return Name;
  }

  if (tok::isStringLiteral(Tok.getKind()))
    return stringLiteralParser(P);

  P.Diag(Tok.getLocation(),
         diag::warn_omp_declare_variant_string_literal_or_identifier)
      << Lvl;
  return "";
}

static bool checkForDuplicates(Parser &P, StringRef Name,
                               SourceLocation NameLoc,
                               llvm::StringMap<SourceLocation> &Seen,
                               OMPContextLvl Lvl) {
  auto Res = Seen.try_emplace(Name, NameLoc);
  if (Res.second)
    return false;

  // Each trait-set-selector-name, trait-selector-name and trait-name can
  // only be specified once.
  P.Diag(NameLoc, diag::warn_omp_declare_variant_ctx_mutiple_use)
      << Lvl << Name;
  P.Diag(Res.first->getValue(), diag::note_omp_declare_variant_ctx_used_here)
      << Lvl << Name;
  return true;
}
} // namespace

void Parser::parseOMPTraitPropertyKind(
    OMPTraitProperty &TIProperty, llvm::omp::TraitSet Set,
    llvm::omp::TraitSelector Selector, llvm::StringMap<SourceLocation> &Seen) {
  TIProperty.Kind = TraitProperty::invalid;

  SourceLocation NameLoc = Tok.getLocation();
  StringRef Name =
      getNameFromIdOrString(*this, Tok, CONTEXT_TRAIT_LVL);
  if (Name.empty()) {
    Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_options)
        << CONTEXT_TRAIT_LVL << listOpenMPContextTraitProperties(Set, Selector);
    return;
  }

  TIProperty.RawString = Name;
  TIProperty.Kind = getOpenMPContextTraitPropertyKind(Set, Selector, Name);
  if (TIProperty.Kind != TraitProperty::invalid) {
    if (checkForDuplicates(*this, Name, NameLoc, Seen, CONTEXT_TRAIT_LVL))
      TIProperty.Kind = TraitProperty::invalid;
    return;
  }

  // It follows diagnosis and helping notes.
  // FIXME: We should move the diagnosis string generation into libFrontend.
  Diag(NameLoc, diag::warn_omp_declare_variant_ctx_not_a_property)
      << Name << getOpenMPContextTraitSelectorName(Selector)
      << getOpenMPContextTraitSetName(Set);

  TraitSet SetForName = getOpenMPContextTraitSetKind(Name);
  if (SetForName != TraitSet::invalid) {
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_SELECTOR_SET_LVL << CONTEXT_TRAIT_LVL;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << Name << "<selector-name>"
        << "(<property-name>)";
    return;
  }
  TraitSelector SelectorForName = getOpenMPContextTraitSelectorKind(Name);
  if (SelectorForName != TraitSelector::invalid) {
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_SELECTOR_LVL << CONTEXT_TRAIT_LVL;
    bool AllowsTraitScore = false;
    bool RequiresProperty = false;
    isValidTraitSelectorForTraitSet(
        SelectorForName, getOpenMPContextTraitSetForSelector(SelectorForName),
        AllowsTraitScore, RequiresProperty);
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForSelector(SelectorForName))
        << Name << (RequiresProperty ? "(<property-name>)" : "");
    return;
  }
  for (const auto &PotentialSet :
       {TraitSet::construct, TraitSet::user, TraitSet::implementation,
        TraitSet::device}) {
    TraitProperty PropertyForName =
        getOpenMPContextTraitPropertyKind(PotentialSet, Selector, Name);
    if (PropertyForName == TraitProperty::invalid)
      continue;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForProperty(PropertyForName))
        << getOpenMPContextTraitSelectorName(
               getOpenMPContextTraitSelectorForProperty(PropertyForName))
        << ("(" + Name + ")").str();
    return;
  }
  Diag(NameLoc, diag::note_omp_declare_variant_ctx_options)
      << CONTEXT_TRAIT_LVL << listOpenMPContextTraitProperties(Set, Selector);
}

static bool checkExtensionProperty(Parser &P, SourceLocation Loc,
                                   OMPTraitProperty &TIProperty,
                                   OMPTraitSelector &TISelector,
                                   llvm::StringMap<SourceLocation> &Seen) {
  assert(TISelector.Kind ==
             llvm::omp::TraitSelector::implementation_extension &&
         "Only for extension properties, e.g., "
         "`implementation={extension(PROPERTY)}`");
  if (TIProperty.Kind == TraitProperty::invalid)
    return false;

  auto IsMatchExtension = [](OMPTraitProperty &TP) {
    return (TP.Kind ==
                llvm::omp::TraitProperty::implementation_extension_match_all ||
            TP.Kind ==
                llvm::omp::TraitProperty::implementation_extension_match_any ||
            TP.Kind ==
                llvm::omp::TraitProperty::implementation_extension_match_none);
  };

  if (IsMatchExtension(TIProperty)) {
    for (OMPTraitProperty &SeenProp : TISelector.Properties)
      if (IsMatchExtension(SeenProp)) {
        P.Diag(Loc, diag::err_omp_variant_ctx_second_match_extension);
        StringRef SeenName = llvm::omp::getOpenMPContextTraitPropertyName(
            SeenProp.Kind, SeenProp.RawString);
        SourceLocation SeenLoc = Seen[SeenName];
        P.Diag(SeenLoc, diag::note_omp_declare_variant_ctx_used_here)
            << CONTEXT_TRAIT_LVL << SeenName;
        return false;
      }
    return true;
  }

  llvm_unreachable("Unknown extension property!");
}

void Parser::parseOMPContextProperty(OMPTraitSelector &TISelector,
                                     llvm::omp::TraitSet Set,
                                     llvm::StringMap<SourceLocation> &Seen) {
  assert(TISelector.Kind != TraitSelector::user_condition &&
         "User conditions are special properties not handled here!");

  SourceLocation PropertyLoc = Tok.getLocation();
  OMPTraitProperty TIProperty;
  parseOMPTraitPropertyKind(TIProperty, Set, TISelector.Kind, Seen);

  if (TISelector.Kind == llvm::omp::TraitSelector::implementation_extension)
    if (!checkExtensionProperty(*this, Tok.getLocation(), TIProperty,
                                TISelector, Seen))
      TIProperty.Kind = TraitProperty::invalid;

  // If we have an invalid property here we already issued a warning.
  if (TIProperty.Kind == TraitProperty::invalid) {
    if (PropertyLoc != Tok.getLocation())
      Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_continue_here)
          << CONTEXT_TRAIT_LVL;
    return;
  }

  if (isValidTraitPropertyForTraitSetAndSelector(TIProperty.Kind,
                                                 TISelector.Kind, Set)) {

    // If we make it here the property, selector, set, score, condition, ... are
    // all valid (or have been corrected). Thus we can record the property.
    TISelector.Properties.push_back(TIProperty);
    return;
  }

  Diag(PropertyLoc, diag::warn_omp_ctx_incompatible_property_for_selector)
      << getOpenMPContextTraitPropertyName(TIProperty.Kind,
                                           TIProperty.RawString)
      << getOpenMPContextTraitSelectorName(TISelector.Kind)
      << getOpenMPContextTraitSetName(Set);
  Diag(PropertyLoc, diag::note_omp_ctx_compatible_set_and_selector_for_property)
      << getOpenMPContextTraitPropertyName(TIProperty.Kind,
                                           TIProperty.RawString)
      << getOpenMPContextTraitSelectorName(
             getOpenMPContextTraitSelectorForProperty(TIProperty.Kind))
      << getOpenMPContextTraitSetName(
             getOpenMPContextTraitSetForProperty(TIProperty.Kind));
  Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_continue_here)
      << CONTEXT_TRAIT_LVL;
}

void Parser::parseOMPTraitSelectorKind(
    OMPTraitSelector &TISelector, llvm::omp::TraitSet Set,
    llvm::StringMap<SourceLocation> &Seen) {
  TISelector.Kind = TraitSelector::invalid;

  SourceLocation NameLoc = Tok.getLocation();
  StringRef Name = getNameFromIdOrString(*this, Tok, CONTEXT_SELECTOR_LVL
                    );
  if (Name.empty()) {
    Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_options)
        << CONTEXT_SELECTOR_LVL << listOpenMPContextTraitSelectors(Set);
    return;
  }

  TISelector.Kind = getOpenMPContextTraitSelectorKind(Name);
  if (TISelector.Kind != TraitSelector::invalid) {
    if (checkForDuplicates(*this, Name, NameLoc, Seen, CONTEXT_SELECTOR_LVL))
      TISelector.Kind = TraitSelector::invalid;
    return;
  }

  // It follows diagnosis and helping notes.
  Diag(NameLoc, diag::warn_omp_declare_variant_ctx_not_a_selector)
      << Name << getOpenMPContextTraitSetName(Set);

  TraitSet SetForName = getOpenMPContextTraitSetKind(Name);
  if (SetForName != TraitSet::invalid) {
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_SELECTOR_SET_LVL << CONTEXT_SELECTOR_LVL;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << Name << "<selector-name>"
        << "<property-name>";
    return;
  }
  for (const auto &PotentialSet :
       {TraitSet::construct, TraitSet::user, TraitSet::implementation,
        TraitSet::device}) {
    TraitProperty PropertyForName = getOpenMPContextTraitPropertyKind(
        PotentialSet, TraitSelector::invalid, Name);
    if (PropertyForName == TraitProperty::invalid)
      continue;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_TRAIT_LVL << CONTEXT_SELECTOR_LVL;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForProperty(PropertyForName))
        << getOpenMPContextTraitSelectorName(
               getOpenMPContextTraitSelectorForProperty(PropertyForName))
        << ("(" + Name + ")").str();
    return;
  }
  Diag(NameLoc, diag::note_omp_declare_variant_ctx_options)
      << CONTEXT_SELECTOR_LVL << listOpenMPContextTraitSelectors(Set);
}

/// Parse optional 'score' '(' <expr> ')' ':'.
static ExprResult parseContextScore(Parser &P) {
  ExprResult ScoreExpr;
  llvm::SmallString<16> Buffer;
  StringRef SelectorName =
      P.getPreprocessor().getSpelling(P.getCurToken(), Buffer);
  if (!SelectorName.equals("score"))
    return ScoreExpr;
  (void)P.ConsumeToken();
  SourceLocation RLoc;
  ScoreExpr = P.ParseOpenMPParensExpr(SelectorName, RLoc);
  // Parse ':'
  if (P.getCurToken().is(tok::colon))
    (void)P.ConsumeAnyToken();
  else
    P.Diag(P.getCurToken(), diag::warn_omp_declare_variant_expected)
        << "':'"
        << "score expression";
  return ScoreExpr;
}

/// Parses an OpenMP context selector.
///
/// <trait-selector-name> ['('[<trait-score>] <trait-property> [, <t-p>]* ')']
void Parser::parseOMPContextSelector(
    OMPTraitSelector &TISelector, llvm::omp::TraitSet Set,
    llvm::StringMap<SourceLocation> &SeenSelectors) {
  unsigned short OuterPC = ParenCount;

  // If anything went wrong we issue an error or warning and then skip the rest
  // of the selector. However, commas are ambiguous so we look for the nesting
  // of parentheses here as well.
  auto FinishSelector = [OuterPC, this]() -> void {
    bool Done = false;
    while (!Done) {
      while (!SkipUntil({tok::r_brace, tok::r_paren, tok::comma,
                         tok::annot_pragma_openmp_end},
                        StopBeforeMatch))
        ;
      if (Tok.is(tok::r_paren) && OuterPC > ParenCount)
        (void)ConsumeParen();
      if (OuterPC <= ParenCount) {
        Done = true;
        break;
      }
      if (!Tok.is(tok::comma) && !Tok.is(tok::r_paren)) {
        Done = true;
        break;
      }
      (void)ConsumeAnyToken();
    }
    Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_continue_here)
        << CONTEXT_SELECTOR_LVL;
  };

  SourceLocation SelectorLoc = Tok.getLocation();
  parseOMPTraitSelectorKind(TISelector, Set, SeenSelectors);
  if (TISelector.Kind == TraitSelector::invalid)
    return FinishSelector();

  bool AllowsTraitScore = false;
  bool RequiresProperty = false;
  if (!isValidTraitSelectorForTraitSet(TISelector.Kind, Set, AllowsTraitScore,
                                       RequiresProperty)) {
    Diag(SelectorLoc, diag::warn_omp_ctx_incompatible_selector_for_set)
        << getOpenMPContextTraitSelectorName(TISelector.Kind)
        << getOpenMPContextTraitSetName(Set);
    Diag(SelectorLoc, diag::note_omp_ctx_compatible_set_for_selector)
        << getOpenMPContextTraitSelectorName(TISelector.Kind)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForSelector(TISelector.Kind))
        << RequiresProperty;
    return FinishSelector();
  }

  if (!RequiresProperty) {
    TISelector.Properties.push_back(
        {getOpenMPContextTraitPropertyForSelector(TISelector.Kind),
         getOpenMPContextTraitSelectorName(TISelector.Kind)});
    return;
  }

  if (!Tok.is(tok::l_paren)) {
    Diag(SelectorLoc, diag::warn_omp_ctx_selector_without_properties)
        << getOpenMPContextTraitSelectorName(TISelector.Kind)
        << getOpenMPContextTraitSetName(Set);
    return FinishSelector();
  }

  if (TISelector.Kind == TraitSelector::user_condition) {
    SourceLocation RLoc;
    ExprResult Condition = ParseOpenMPParensExpr("user condition", RLoc);
    if (!Condition.isUsable())
      return FinishSelector();
    TISelector.ScoreOrCondition = Condition.get();
    TISelector.Properties.push_back(
        {TraitProperty::user_condition_unknown, "<condition>"});
    return;
  }

  BalancedDelimiterTracker BDT(*this, tok::l_paren,
                               tok::annot_pragma_openmp_end);
  // Parse '('.
  (void)BDT.consumeOpen();

  SourceLocation ScoreLoc = Tok.getLocation();
  ExprResult Score = parseContextScore(*this);

  if (!AllowsTraitScore && !Score.isUnset()) {
    if (Score.isUsable()) {
      Diag(ScoreLoc, diag::warn_omp_ctx_incompatible_score_for_property)
          << getOpenMPContextTraitSelectorName(TISelector.Kind)
          << getOpenMPContextTraitSetName(Set) << Score.get();
    } else {
      Diag(ScoreLoc, diag::warn_omp_ctx_incompatible_score_for_property)
          << getOpenMPContextTraitSelectorName(TISelector.Kind)
          << getOpenMPContextTraitSetName(Set) << "<invalid>";
    }
    Score = ExprResult();
  }

  if (Score.isUsable())
    TISelector.ScoreOrCondition = Score.get();

  llvm::StringMap<SourceLocation> SeenProperties;
  do {
    parseOMPContextProperty(TISelector, Set, SeenProperties);
  } while (TryConsumeToken(tok::comma));

  // Parse ')'.
  BDT.consumeClose();
}

void Parser::parseOMPTraitSetKind(OMPTraitSet &TISet,
                                  llvm::StringMap<SourceLocation> &Seen) {
  TISet.Kind = TraitSet::invalid;

  SourceLocation NameLoc = Tok.getLocation();
  StringRef Name = getNameFromIdOrString(*this, Tok, CONTEXT_SELECTOR_SET_LVL
                   );
  if (Name.empty()) {
    Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_options)
        << CONTEXT_SELECTOR_SET_LVL << listOpenMPContextTraitSets();
    return;
  }

  TISet.Kind = getOpenMPContextTraitSetKind(Name);
  if (TISet.Kind != TraitSet::invalid) {
    if (checkForDuplicates(*this, Name, NameLoc, Seen,
                           CONTEXT_SELECTOR_SET_LVL))
      TISet.Kind = TraitSet::invalid;
    return;
  }

  // It follows diagnosis and helping notes.
  Diag(NameLoc, diag::warn_omp_declare_variant_ctx_not_a_set) << Name;

  TraitSelector SelectorForName = getOpenMPContextTraitSelectorKind(Name);
  if (SelectorForName != TraitSelector::invalid) {
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_SELECTOR_LVL << CONTEXT_SELECTOR_SET_LVL;
    bool AllowsTraitScore = false;
    bool RequiresProperty = false;
    isValidTraitSelectorForTraitSet(
        SelectorForName, getOpenMPContextTraitSetForSelector(SelectorForName),
        AllowsTraitScore, RequiresProperty);
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForSelector(SelectorForName))
        << Name << (RequiresProperty ? "(<property-name>)" : "");
    return;
  }
  for (const auto &PotentialSet :
       {TraitSet::construct, TraitSet::user, TraitSet::implementation,
        TraitSet::device}) {
    TraitProperty PropertyForName = getOpenMPContextTraitPropertyKind(
        PotentialSet, TraitSelector::invalid, Name);
    if (PropertyForName == TraitProperty::invalid)
      continue;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_is_a)
        << Name << CONTEXT_TRAIT_LVL << CONTEXT_SELECTOR_SET_LVL;
    Diag(NameLoc, diag::note_omp_declare_variant_ctx_try)
        << getOpenMPContextTraitSetName(
               getOpenMPContextTraitSetForProperty(PropertyForName))
        << getOpenMPContextTraitSelectorName(
               getOpenMPContextTraitSelectorForProperty(PropertyForName))
        << ("(" + Name + ")").str();
    return;
  }
  Diag(NameLoc, diag::note_omp_declare_variant_ctx_options)
      << CONTEXT_SELECTOR_SET_LVL << listOpenMPContextTraitSets();
}

/// Parses an OpenMP context selector set.
///
/// <trait-set-selector-name> '=' '{' <trait-selector> [, <trait-selector>]* '}'
void Parser::parseOMPContextSelectorSet(
    OMPTraitSet &TISet,
    llvm::StringMap<SourceLocation> &SeenSets) {
  auto OuterBC = BraceCount;

  // If anything went wrong we issue an error or warning and then skip the rest
  // of the set. However, commas are ambiguous so we look for the nesting
  // of braces here as well.
  auto FinishSelectorSet = [this, OuterBC]() -> void {
    bool Done = false;
    while (!Done) {
      while (!SkipUntil({tok::comma, tok::r_brace, tok::r_paren,
                         tok::annot_pragma_openmp_end},
                        StopBeforeMatch))
        ;
      if (Tok.is(tok::r_brace) && OuterBC > BraceCount)
        (void)ConsumeBrace();
      if (OuterBC <= BraceCount) {
        Done = true;
        break;
      }
      if (!Tok.is(tok::comma) && !Tok.is(tok::r_brace)) {
        Done = true;
        break;
      }
      (void)ConsumeAnyToken();
    }
    Diag(Tok.getLocation(), diag::note_omp_declare_variant_ctx_continue_here)
        << CONTEXT_SELECTOR_SET_LVL;
  };

  parseOMPTraitSetKind(TISet, SeenSets);
  if (TISet.Kind == TraitSet::invalid)
    return FinishSelectorSet();

  // Parse '='.
  if (!TryConsumeToken(tok::equal))
    Diag(Tok.getLocation(), diag::warn_omp_declare_variant_expected)
        << "="
        << ("context set name \"" + getOpenMPContextTraitSetName(TISet.Kind) +
            "\"")
               .str();

  // Parse '{'.
  if (Tok.is(tok::l_brace)) {
    (void)ConsumeBrace();
  } else {
    Diag(Tok.getLocation(), diag::warn_omp_declare_variant_expected)
        << "{"
        << ("'=' that follows the context set name \"" +
            getOpenMPContextTraitSetName(TISet.Kind) + "\"")
               .str();
  }

  llvm::StringMap<SourceLocation> SeenSelectors;
  do {
    OMPTraitSelector TISelector;
    parseOMPContextSelector(TISelector, TISet.Kind, SeenSelectors);
    if (TISelector.Kind != TraitSelector::invalid &&
        !TISelector.Properties.empty())
      TISet.Selectors.push_back(TISelector);
  } while (TryConsumeToken(tok::comma));

  // Parse '}'.
  if (Tok.is(tok::r_brace)) {
    (void)ConsumeBrace();
  } else {
    Diag(Tok.getLocation(), diag::warn_omp_declare_variant_expected)
        << "}"
        << ("context selectors for the context set \"" +
            getOpenMPContextTraitSetName(TISet.Kind) + "\"")
               .str();
  }
}

/// Parse OpenMP context selectors:
///
/// <trait-set-selector> [, <trait-set-selector>]*
bool Parser::parseOMPContextSelectors(SourceLocation Loc, OMPTraitInfo& TI) {
  llvm::StringMap<SourceLocation> SeenSets;
  do {
    OMPTraitSet TISet;
    parseOMPContextSelectorSet(TISet, SeenSets);
    if (TISet.Kind != TraitSet::invalid && !TISet.Selectors.empty())
      TI.Sets.push_back(TISet);
  } while (TryConsumeToken(tok::comma));

  return false;
}

/// Parse clauses for '#pragma omp declare variant ( variant-func-id ) clause'.
void Parser::ParseOMPDeclareVariantClauses(Parser::DeclGroupPtrTy Ptr,
                                           CachedTokens &Toks,
                                           SourceLocation Loc) {
  PP.EnterToken(Tok, /*IsReinject*/ true);
  PP.EnterTokenStream(Toks, /*DisableMacroExpansion=*/true,
                      /*IsReinject*/ true);
  // Consume the previously pushed token.
  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);

  FNContextRAII FnContext(*this, Ptr);
  // Parse function declaration id.
  SourceLocation RLoc;
  // Parse with IsAddressOfOperand set to true to parse methods as DeclRefExprs
  // instead of MemberExprs.
  ExprResult AssociatedFunction;
  {
    // Do not mark function as is used to prevent its emission if this is the
    // only place where it is used.
    EnterExpressionEvaluationContext Unevaluated(
        Actions, Sema::ExpressionEvaluationContext::Unevaluated);
    AssociatedFunction = ParseOpenMPParensExpr(
        getOpenMPDirectiveName(OMPD_declare_variant), RLoc,
        /*IsAddressOfOperand=*/true);
  }
  if (!AssociatedFunction.isUsable()) {
    if (!Tok.is(tok::annot_pragma_openmp_end))
      while (!SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch))
        ;
    // Skip the last annot_pragma_openmp_end.
    (void)ConsumeAnnotationToken();
    return;
  }

  OMPTraitInfo &TI = Actions.getASTContext().getNewOMPTraitInfo();
  if (parseOMPDeclareVariantMatchClause(Loc, TI))
    return;

  Optional<std::pair<FunctionDecl *, Expr *>> DeclVarData =
      Actions.checkOpenMPDeclareVariantFunction(
          Ptr, AssociatedFunction.get(), TI,
          SourceRange(Loc, Tok.getLocation()));

  // Skip last tokens.
  while (Tok.isNot(tok::annot_pragma_openmp_end))
    ConsumeAnyToken();
  if (DeclVarData && !TI.Sets.empty())
    Actions.ActOnOpenMPDeclareVariantDirective(
        DeclVarData->first, DeclVarData->second, TI,
        SourceRange(Loc, Tok.getLocation()));

  // Skip the last annot_pragma_openmp_end.
  (void)ConsumeAnnotationToken();
}

bool Parser::parseOMPDeclareVariantMatchClause(SourceLocation Loc,
                                               OMPTraitInfo &TI) {
  // Parse 'match'.
  OpenMPClauseKind CKind = Tok.isAnnotation()
                               ? OMPC_unknown
                               : getOpenMPClauseKind(PP.getSpelling(Tok));
  if (CKind != OMPC_match) {
    Diag(Tok.getLocation(), diag::err_omp_declare_variant_wrong_clause)
        << getOpenMPClauseName(OMPC_match);
    while (!SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch))
      ;
    // Skip the last annot_pragma_openmp_end.
    (void)ConsumeAnnotationToken();
    return true;
  }
  (void)ConsumeToken();
  // Parse '('.
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after,
                         getOpenMPClauseName(OMPC_match).data())) {
    while (!SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch))
      ;
    // Skip the last annot_pragma_openmp_end.
    (void)ConsumeAnnotationToken();
    return true;
  }

  // Parse inner context selectors.
  parseOMPContextSelectors(Loc, TI);

  // Parse ')'
  (void)T.consumeClose();
  return false;
}

/// Parsing of simple OpenMP clauses like 'default' or 'proc_bind'.
///
///    default-clause:
///         'default' '(' 'none' | 'shared'  | 'firstprivate' ')
///
///    proc_bind-clause:
///         'proc_bind' '(' 'master' | 'close' | 'spread' ')
///
///    device_type-clause:
///         'device_type' '(' 'host' | 'nohost' | 'any' )'
namespace {
  struct SimpleClauseData {
    unsigned Type;
    SourceLocation Loc;
    SourceLocation LOpen;
    SourceLocation TypeLoc;
    SourceLocation RLoc;
    SimpleClauseData(unsigned Type, SourceLocation Loc, SourceLocation LOpen,
                     SourceLocation TypeLoc, SourceLocation RLoc)
        : Type(Type), Loc(Loc), LOpen(LOpen), TypeLoc(TypeLoc), RLoc(RLoc) {}
  };
} // anonymous namespace

static Optional<SimpleClauseData>
parseOpenMPSimpleClause(Parser &P, OpenMPClauseKind Kind) {
  const Token &Tok = P.getCurToken();
  SourceLocation Loc = Tok.getLocation();
  SourceLocation LOpen = P.ConsumeToken();
  // Parse '('.
  BalancedDelimiterTracker T(P, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after,
                         getOpenMPClauseName(Kind).data()))
    return llvm::None;

  unsigned Type = getOpenMPSimpleClauseType(
      Kind, Tok.isAnnotation() ? "" : P.getPreprocessor().getSpelling(Tok),
      P.getLangOpts().OpenMP);
  SourceLocation TypeLoc = Tok.getLocation();
  if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::comma) &&
      Tok.isNot(tok::annot_pragma_openmp_end))
    P.ConsumeAnyToken();

  // Parse ')'.
  SourceLocation RLoc = Tok.getLocation();
  if (!T.consumeClose())
    RLoc = T.getCloseLocation();

  return SimpleClauseData(Type, Loc, LOpen, TypeLoc, RLoc);
}

Parser::DeclGroupPtrTy Parser::ParseOMPDeclareTargetClauses() {
  // OpenMP 4.5 syntax with list of entities.
  Sema::NamedDeclSetType SameDirectiveDecls;
  SmallVector<std::tuple<OMPDeclareTargetDeclAttr::MapTypeTy, SourceLocation,
                         NamedDecl *>,
              4>
      DeclareTargetDecls;
  OMPDeclareTargetDeclAttr::DevTypeTy DT = OMPDeclareTargetDeclAttr::DT_Any;
  SourceLocation DeviceTypeLoc;
  while (Tok.isNot(tok::annot_pragma_openmp_end)) {
    OMPDeclareTargetDeclAttr::MapTypeTy MT = OMPDeclareTargetDeclAttr::MT_To;
    if (Tok.is(tok::identifier)) {
      IdentifierInfo *II = Tok.getIdentifierInfo();
      StringRef ClauseName = II->getName();
      bool IsDeviceTypeClause =
          getLangOpts().OpenMP >= 50 &&
          getOpenMPClauseKind(ClauseName) == OMPC_device_type;
      // Parse 'to|link|device_type' clauses.
      if (!OMPDeclareTargetDeclAttr::ConvertStrToMapTypeTy(ClauseName, MT) &&
          !IsDeviceTypeClause) {
        Diag(Tok, diag::err_omp_declare_target_unexpected_clause)
            << ClauseName << (getLangOpts().OpenMP >= 50 ? 1 : 0);
        break;
      }
      // Parse 'device_type' clause and go to next clause if any.
      if (IsDeviceTypeClause) {
        Optional<SimpleClauseData> DevTypeData =
            parseOpenMPSimpleClause(*this, OMPC_device_type);
        if (DevTypeData.hasValue()) {
          if (DeviceTypeLoc.isValid()) {
            // We already saw another device_type clause, diagnose it.
            Diag(DevTypeData.getValue().Loc,
                 diag::warn_omp_more_one_device_type_clause);
          }
          switch(static_cast<OpenMPDeviceType>(DevTypeData.getValue().Type)) {
          case OMPC_DEVICE_TYPE_any:
            DT = OMPDeclareTargetDeclAttr::DT_Any;
            break;
          case OMPC_DEVICE_TYPE_host:
            DT = OMPDeclareTargetDeclAttr::DT_Host;
            break;
          case OMPC_DEVICE_TYPE_nohost:
            DT = OMPDeclareTargetDeclAttr::DT_NoHost;
            break;
          case OMPC_DEVICE_TYPE_unknown:
            llvm_unreachable("Unexpected device_type");
          }
          DeviceTypeLoc = DevTypeData.getValue().Loc;
        }
        continue;
      }
      ConsumeToken();
    }
    auto &&Callback = [this, MT, &DeclareTargetDecls, &SameDirectiveDecls](
                          CXXScopeSpec &SS, DeclarationNameInfo NameInfo) {
      NamedDecl *ND = Actions.lookupOpenMPDeclareTargetName(
          getCurScope(), SS, NameInfo, SameDirectiveDecls);
      if (ND)
        DeclareTargetDecls.emplace_back(MT, NameInfo.getLoc(), ND);
    };
    if (ParseOpenMPSimpleVarList(OMPD_declare_target, Callback,
                                 /*AllowScopeSpecifier=*/true))
      break;

    // Consume optional ','.
    if (Tok.is(tok::comma))
      ConsumeToken();
  }
  SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
  ConsumeAnyToken();
  for (auto &MTLocDecl : DeclareTargetDecls) {
    OMPDeclareTargetDeclAttr::MapTypeTy MT;
    SourceLocation Loc;
    NamedDecl *ND;
    std::tie(MT, Loc, ND) = MTLocDecl;
    // device_type clause is applied only to functions.
    Actions.ActOnOpenMPDeclareTargetName(
        ND, Loc, MT, isa<VarDecl>(ND) ? OMPDeclareTargetDeclAttr::DT_Any : DT);
  }
  SmallVector<Decl *, 4> Decls(SameDirectiveDecls.begin(),
                               SameDirectiveDecls.end());
  if (Decls.empty())
    return DeclGroupPtrTy();
  return Actions.BuildDeclaratorGroup(Decls);
}

void Parser::skipUntilPragmaOpenMPEnd(OpenMPDirectiveKind DKind) {
  // The last seen token is annot_pragma_openmp_end - need to check for
  // extra tokens.
  if (Tok.is(tok::annot_pragma_openmp_end))
    return;

  Diag(Tok, diag::warn_omp_extra_tokens_at_eol)
      << getOpenMPDirectiveName(DKind);
  while (Tok.isNot(tok::annot_pragma_openmp_end))
    ConsumeAnyToken();
}

void Parser::parseOMPEndDirective(OpenMPDirectiveKind BeginKind,
                                  OpenMPDirectiveKind ExpectedKind,
                                  OpenMPDirectiveKind FoundKind,
                                  SourceLocation BeginLoc,
                                  SourceLocation FoundLoc,
                                  bool SkipUntilOpenMPEnd) {
  int DiagSelection = ExpectedKind == OMPD_end_declare_target ? 0 : 1;

  if (FoundKind == ExpectedKind) {
    ConsumeAnyToken();
    skipUntilPragmaOpenMPEnd(ExpectedKind);
    return;
  }

  Diag(FoundLoc, diag::err_expected_end_declare_target_or_variant)
      << DiagSelection;
  Diag(BeginLoc, diag::note_matching)
      << ("'#pragma omp " + getOpenMPDirectiveName(BeginKind) + "'").str();
  if (SkipUntilOpenMPEnd)
    SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
}

void Parser::ParseOMPEndDeclareTargetDirective(OpenMPDirectiveKind DKind,
                                               SourceLocation DKLoc) {
  parseOMPEndDirective(OMPD_declare_target, OMPD_end_declare_target, DKind,
                       DKLoc, Tok.getLocation(),
                       /* SkipUntilOpenMPEnd */ false);
  // Skip the last annot_pragma_openmp_end.
  if (Tok.is(tok::annot_pragma_openmp_end))
    ConsumeAnnotationToken();
}

/// Parsing of declarative OpenMP directives.
///
///       threadprivate-directive:
///         annot_pragma_openmp 'threadprivate' simple-variable-list
///         annot_pragma_openmp_end
///
///       allocate-directive:
///         annot_pragma_openmp 'allocate' simple-variable-list [<clause>]
///         annot_pragma_openmp_end
///
///       declare-reduction-directive:
///        annot_pragma_openmp 'declare' 'reduction' [...]
///        annot_pragma_openmp_end
///
///       declare-mapper-directive:
///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
///         annot_pragma_openmp_end
///
///       declare-simd-directive:
///         annot_pragma_openmp 'declare simd' {<clause> [,]}
///         annot_pragma_openmp_end
///         <function declaration/definition>
///
///       requires directive:
///         annot_pragma_openmp 'requires' <clause> [[[,] <clause>] ... ]
///         annot_pragma_openmp_end
///
Parser::DeclGroupPtrTy Parser::ParseOpenMPDeclarativeDirectiveWithExtDecl(
    AccessSpecifier &AS, ParsedAttributesWithRange &Attrs, bool Delayed,
    DeclSpec::TST TagType, Decl *Tag) {
  assert(Tok.is(tok::annot_pragma_openmp) && "Not an OpenMP directive!");
  ParsingOpenMPDirectiveRAII DirScope(*this);
  ParenBraceBracketBalancer BalancerRAIIObj(*this);

  SourceLocation Loc;
  OpenMPDirectiveKind DKind;
  if (Delayed) {
    TentativeParsingAction TPA(*this);
    Loc = ConsumeAnnotationToken();
    DKind = parseOpenMPDirectiveKind(*this);
    if (DKind == OMPD_declare_reduction || DKind == OMPD_declare_mapper) {
      // Need to delay parsing until completion of the parent class.
      TPA.Revert();
      CachedTokens Toks;
      unsigned Cnt = 1;
      Toks.push_back(Tok);
      while (Cnt && Tok.isNot(tok::eof)) {
        (void)ConsumeAnyToken();
        if (Tok.is(tok::annot_pragma_openmp))
          ++Cnt;
        else if (Tok.is(tok::annot_pragma_openmp_end))
          --Cnt;
        Toks.push_back(Tok);
      }
      // Skip last annot_pragma_openmp_end.
      if (Cnt == 0)
        (void)ConsumeAnyToken();
      auto *LP = new LateParsedPragma(this, AS);
      LP->takeToks(Toks);
      getCurrentClass().LateParsedDeclarations.push_back(LP);
      return nullptr;
    }
    TPA.Commit();
  } else {
    Loc = ConsumeAnnotationToken();
    DKind = parseOpenMPDirectiveKind(*this);
  }

  switch (DKind) {
  case OMPD_threadprivate: {
    ConsumeToken();
    DeclDirectiveListParserHelper Helper(this, DKind);
    if (!ParseOpenMPSimpleVarList(DKind, Helper,
                                  /*AllowScopeSpecifier=*/true)) {
      skipUntilPragmaOpenMPEnd(DKind);
      // Skip the last annot_pragma_openmp_end.
      ConsumeAnnotationToken();
      return Actions.ActOnOpenMPThreadprivateDirective(Loc,
                                                       Helper.getIdentifiers());
    }
    break;
  }
  case OMPD_allocate: {
    ConsumeToken();
    DeclDirectiveListParserHelper Helper(this, DKind);
    if (!ParseOpenMPSimpleVarList(DKind, Helper,
                                  /*AllowScopeSpecifier=*/true)) {
      SmallVector<OMPClause *, 1> Clauses;
      if (Tok.isNot(tok::annot_pragma_openmp_end)) {
        SmallVector<llvm::PointerIntPair<OMPClause *, 1, bool>,
                    llvm::omp::Clause_enumSize + 1>
            FirstClauses(llvm::omp::Clause_enumSize + 1);
        while (Tok.isNot(tok::annot_pragma_openmp_end)) {
          OpenMPClauseKind CKind =
              Tok.isAnnotation() ? OMPC_unknown
                                 : getOpenMPClauseKind(PP.getSpelling(Tok));
          Actions.StartOpenMPClause(CKind);
          OMPClause *Clause = ParseOpenMPClause(
              OMPD_allocate, CKind, !FirstClauses[unsigned(CKind)].getInt());
          SkipUntil(tok::comma, tok::identifier, tok::annot_pragma_openmp_end,
                    StopBeforeMatch);
          FirstClauses[unsigned(CKind)].setInt(true);
          if (Clause != nullptr)
            Clauses.push_back(Clause);
          if (Tok.is(tok::annot_pragma_openmp_end)) {
            Actions.EndOpenMPClause();
            break;
          }
          // Skip ',' if any.
          if (Tok.is(tok::comma))
            ConsumeToken();
          Actions.EndOpenMPClause();
        }
        skipUntilPragmaOpenMPEnd(DKind);
      }
      // Skip the last annot_pragma_openmp_end.
      ConsumeAnnotationToken();
      return Actions.ActOnOpenMPAllocateDirective(Loc, Helper.getIdentifiers(),
                                                  Clauses);
    }
    break;
  }
  case OMPD_requires: {
    SourceLocation StartLoc = ConsumeToken();
    SmallVector<OMPClause *, 5> Clauses;
    SmallVector<llvm::PointerIntPair<OMPClause *, 1, bool>,
                llvm::omp::Clause_enumSize + 1>
        FirstClauses(llvm::omp::Clause_enumSize + 1);
    if (Tok.is(tok::annot_pragma_openmp_end)) {
      Diag(Tok, diag::err_omp_expected_clause)
          << getOpenMPDirectiveName(OMPD_requires);
      break;
    }
    while (Tok.isNot(tok::annot_pragma_openmp_end)) {
      OpenMPClauseKind CKind = Tok.isAnnotation()
                                   ? OMPC_unknown
                                   : getOpenMPClauseKind(PP.getSpelling(Tok));
      Actions.StartOpenMPClause(CKind);
      OMPClause *Clause = ParseOpenMPClause(
          OMPD_requires, CKind, !FirstClauses[unsigned(CKind)].getInt());
      SkipUntil(tok::comma, tok::identifier, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
      FirstClauses[unsigned(CKind)].setInt(true);
      if (Clause != nullptr)
        Clauses.push_back(Clause);
      if (Tok.is(tok::annot_pragma_openmp_end)) {
        Actions.EndOpenMPClause();
        break;
      }
      // Skip ',' if any.
      if (Tok.is(tok::comma))
        ConsumeToken();
      Actions.EndOpenMPClause();
    }
    // Consume final annot_pragma_openmp_end
    if (Clauses.empty()) {
      Diag(Tok, diag::err_omp_expected_clause)
          << getOpenMPDirectiveName(OMPD_requires);
      ConsumeAnnotationToken();
      return nullptr;
    }
    ConsumeAnnotationToken();
    return Actions.ActOnOpenMPRequiresDirective(StartLoc, Clauses);
  }
  case OMPD_declare_reduction:
    ConsumeToken();
    if (DeclGroupPtrTy Res = ParseOpenMPDeclareReductionDirective(AS)) {
      skipUntilPragmaOpenMPEnd(OMPD_declare_reduction);
      // Skip the last annot_pragma_openmp_end.
      ConsumeAnnotationToken();
      return Res;
    }
    break;
  case OMPD_declare_mapper: {
    ConsumeToken();
    if (DeclGroupPtrTy Res = ParseOpenMPDeclareMapperDirective(AS)) {
      // Skip the last annot_pragma_openmp_end.
      ConsumeAnnotationToken();
      return Res;
    }
    break;
  }
  case OMPD_begin_declare_variant: {
    // The syntax is:
    // { #pragma omp begin declare variant clause }
    // <function-declaration-or-definition-sequence>
    // { #pragma omp end declare variant }
    //
    ConsumeToken();
    OMPTraitInfo &TI = Actions.getASTContext().getNewOMPTraitInfo();
    if (parseOMPDeclareVariantMatchClause(Loc, TI))
      break;

    // Skip last tokens.
    skipUntilPragmaOpenMPEnd(OMPD_begin_declare_variant);

    ParsingOpenMPDirectiveRAII NormalScope(*this, /*Value=*/false);

    VariantMatchInfo VMI;
    ASTContext &ASTCtx = Actions.getASTContext();
    TI.getAsVariantMatchInfo(ASTCtx, VMI);

    std::function<void(StringRef)> DiagUnknownTrait = [this, Loc](
                                                          StringRef ISATrait) {
      // TODO Track the selector locations in a way that is accessible here to
      // improve the diagnostic location.
      Diag(Loc, diag::warn_unknown_begin_declare_variant_isa_trait) << ISATrait;
    };
    TargetOMPContext OMPCtx(ASTCtx, std::move(DiagUnknownTrait),
                            /* CurrentFunctionDecl */ nullptr);

    if (isVariantApplicableInContext(VMI, OMPCtx, /* DeviceSetOnly */ true)) {
      Actions.ActOnOpenMPBeginDeclareVariant(Loc, TI);
      break;
    }

    // Elide all the code till the matching end declare variant was found.
    unsigned Nesting = 1;
    SourceLocation DKLoc;
    OpenMPDirectiveKind DK = OMPD_unknown;
    do {
      DKLoc = Tok.getLocation();
      DK = parseOpenMPDirectiveKind(*this);
      if (DK == OMPD_end_declare_variant)
        --Nesting;
      else if (DK == OMPD_begin_declare_variant)
        ++Nesting;
      if (!Nesting || isEofOrEom())
        break;
      ConsumeAnyToken();
    } while (true);

    parseOMPEndDirective(OMPD_begin_declare_variant, OMPD_end_declare_variant,
                         DK, Loc, DKLoc, /* SkipUntilOpenMPEnd */ true);
    if (isEofOrEom())
      return nullptr;
    break;
  }
  case OMPD_end_declare_variant: {
    if (Actions.isInOpenMPDeclareVariantScope())
      Actions.ActOnOpenMPEndDeclareVariant();
    else
      Diag(Loc, diag::err_expected_begin_declare_variant);
    ConsumeToken();
    break;
  }
  case OMPD_declare_variant:
  case OMPD_declare_simd: {
    // The syntax is:
    // { #pragma omp declare {simd|variant} }
    // <function-declaration-or-definition>
    //
    CachedTokens Toks;
    Toks.push_back(Tok);
    ConsumeToken();
    while(Tok.isNot(tok::annot_pragma_openmp_end)) {
      Toks.push_back(Tok);
      ConsumeAnyToken();
    }
    Toks.push_back(Tok);
    ConsumeAnyToken();

    DeclGroupPtrTy Ptr;
    if (Tok.is(tok::annot_pragma_openmp)) {
      Ptr = ParseOpenMPDeclarativeDirectiveWithExtDecl(AS, Attrs, Delayed,
                                                       TagType, Tag);
    } else if (Tok.isNot(tok::r_brace) && !isEofOrEom()) {
      // Here we expect to see some function declaration.
      if (AS == AS_none) {
        assert(TagType == DeclSpec::TST_unspecified);
        MaybeParseCXX11Attributes(Attrs);
        ParsingDeclSpec PDS(*this);
        Ptr = ParseExternalDeclaration(Attrs, &PDS);
      } else {
        Ptr =
            ParseCXXClassMemberDeclarationWithPragmas(AS, Attrs, TagType, Tag);
      }
    }
    if (!Ptr) {
      Diag(Loc, diag::err_omp_decl_in_declare_simd_variant)
          << (DKind == OMPD_declare_simd ? 0 : 1);
      return DeclGroupPtrTy();
    }
    if (DKind == OMPD_declare_simd)
      return ParseOMPDeclareSimdClauses(Ptr, Toks, Loc);
    assert(DKind == OMPD_declare_variant &&
           "Expected declare variant directive only");
    ParseOMPDeclareVariantClauses(Ptr, Toks, Loc);
    return Ptr;
  }
  case OMPD_declare_target: {
    SourceLocation DTLoc = ConsumeAnyToken();
    if (Tok.isNot(tok::annot_pragma_openmp_end)) {
      return ParseOMPDeclareTargetClauses();
    }

    // Skip the last annot_pragma_openmp_end.
    ConsumeAnyToken();

    if (!Actions.ActOnStartOpenMPDeclareTargetDirective(DTLoc))
      return DeclGroupPtrTy();

    ParsingOpenMPDirectiveRAII NormalScope(*this, /*Value=*/false);
    llvm::SmallVector<Decl *, 4>  Decls;
    DKind = parseOpenMPDirectiveKind(*this);
    while (DKind != OMPD_end_declare_target && Tok.isNot(tok::eof) &&
           Tok.isNot(tok::r_brace)) {
      DeclGroupPtrTy Ptr;
      // Here we expect to see some function declaration.
      if (AS == AS_none) {
        assert(TagType == DeclSpec::TST_unspecified);
        MaybeParseCXX11Attributes(Attrs);
        ParsingDeclSpec PDS(*this);
        Ptr = ParseExternalDeclaration(Attrs, &PDS);
      } else {
        Ptr =
            ParseCXXClassMemberDeclarationWithPragmas(AS, Attrs, TagType, Tag);
      }
      if (Ptr) {
        DeclGroupRef Ref = Ptr.get();
        Decls.append(Ref.begin(), Ref.end());
      }
      if (Tok.isAnnotation() && Tok.is(tok::annot_pragma_openmp)) {
        TentativeParsingAction TPA(*this);
        ConsumeAnnotationToken();
        DKind = parseOpenMPDirectiveKind(*this);
        if (DKind != OMPD_end_declare_target)
          TPA.Revert();
        else
          TPA.Commit();
      }
    }

    ParseOMPEndDeclareTargetDirective(DKind, DTLoc);
    Actions.ActOnFinishOpenMPDeclareTargetDirective();
    return Actions.BuildDeclaratorGroup(Decls);
  }
  case OMPD_unknown:
    Diag(Tok, diag::err_omp_unknown_directive);
    break;
  case OMPD_parallel:
  case OMPD_simd:
  case OMPD_task:
  case OMPD_taskyield:
  case OMPD_barrier:
  case OMPD_taskwait:
  case OMPD_taskgroup:
  case OMPD_flush:
  case OMPD_depobj:
  case OMPD_scan:
  case OMPD_for:
  case OMPD_for_simd:
  case OMPD_sections:
  case OMPD_section:
  case OMPD_single:
  case OMPD_master:
  case OMPD_ordered:
  case OMPD_critical:
  case OMPD_parallel_for:
  case OMPD_parallel_for_simd:
  case OMPD_parallel_sections:
  case OMPD_parallel_master:
  case OMPD_atomic:
  case OMPD_target:
  case OMPD_teams:
  case OMPD_cancellation_point:
  case OMPD_cancel:
  case OMPD_target_data:
  case OMPD_target_enter_data:
  case OMPD_target_exit_data:
  case OMPD_target_parallel:
  case OMPD_target_parallel_for:
  case OMPD_taskloop:
  case OMPD_taskloop_simd:
  case OMPD_master_taskloop:
  case OMPD_master_taskloop_simd:
  case OMPD_parallel_master_taskloop:
  case OMPD_parallel_master_taskloop_simd:
  case OMPD_distribute:
  case OMPD_end_declare_target:
  case OMPD_target_update:
  case OMPD_distribute_parallel_for:
  case OMPD_distribute_parallel_for_simd:
  case OMPD_distribute_simd:
  case OMPD_target_parallel_for_simd:
  case OMPD_target_simd:
  case OMPD_teams_distribute:
  case OMPD_teams_distribute_simd:
  case OMPD_teams_distribute_parallel_for_simd:
  case OMPD_teams_distribute_parallel_for:
  case OMPD_target_teams:
  case OMPD_target_teams_distribute:
  case OMPD_target_teams_distribute_parallel_for:
  case OMPD_target_teams_distribute_parallel_for_simd:
  case OMPD_target_teams_distribute_simd:
    Diag(Tok, diag::err_omp_unexpected_directive)
        << 1 << getOpenMPDirectiveName(DKind);
    break;
  default:
    break;
  }
  while (Tok.isNot(tok::annot_pragma_openmp_end))
    ConsumeAnyToken();
  ConsumeAnyToken();
  return nullptr;
}

/// Parsing of declarative or executable OpenMP directives.
///
///       threadprivate-directive:
///         annot_pragma_openmp 'threadprivate' simple-variable-list
///         annot_pragma_openmp_end
///
///       allocate-directive:
///         annot_pragma_openmp 'allocate' simple-variable-list
///         annot_pragma_openmp_end
///
///       declare-reduction-directive:
///         annot_pragma_openmp 'declare' 'reduction' '(' <reduction_id> ':'
///         <type> {',' <type>} ':' <expression> ')' ['initializer' '('
///         ('omp_priv' '=' <expression>|<function_call>) ')']
///         annot_pragma_openmp_end
///
///       declare-mapper-directive:
///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
///         annot_pragma_openmp_end
///
///       executable-directive:
///         annot_pragma_openmp 'parallel' | 'simd' | 'for' | 'sections' |
///         'section' | 'single' | 'master' | 'critical' [ '(' <name> ')' ] |
///         'parallel for' | 'parallel sections' | 'parallel master' | 'task' |
///         'taskyield' | 'barrier' | 'taskwait' | 'flush' | 'ordered' |
///         'atomic' | 'for simd' | 'parallel for simd' | 'target' | 'target
///         data' | 'taskgroup' | 'teams' | 'taskloop' | 'taskloop simd' |
///         'master taskloop' | 'master taskloop simd' | 'parallel master
///         taskloop' | 'parallel master taskloop simd' | 'distribute' | 'target
///         enter data' | 'target exit data' | 'target parallel' | 'target
///         parallel for' | 'target update' | 'distribute parallel for' |
///         'distribute paralle for simd' | 'distribute simd' | 'target parallel
///         for simd' | 'target simd' | 'teams distribute' | 'teams distribute
///         simd' | 'teams distribute parallel for simd' | 'teams distribute
///         parallel for' | 'target teams' | 'target teams distribute' | 'target
///         teams distribute parallel for' | 'target teams distribute parallel
///         for simd' | 'target teams distribute simd' {clause}
///         annot_pragma_openmp_end
///
StmtResult
Parser::ParseOpenMPDeclarativeOrExecutableDirective(ParsedStmtContext StmtCtx) {
  assert(Tok.is(tok::annot_pragma_openmp) && "Not an OpenMP directive!");
  ParsingOpenMPDirectiveRAII DirScope(*this);
  ParenBraceBracketBalancer BalancerRAIIObj(*this);
  SmallVector<OMPClause *, 5> Clauses;
  SmallVector<llvm::PointerIntPair<OMPClause *, 1, bool>,
              llvm::omp::Clause_enumSize + 1>
      FirstClauses(llvm::omp::Clause_enumSize + 1);
  unsigned ScopeFlags = Scope::FnScope | Scope::DeclScope |
                        Scope::CompoundStmtScope | Scope::OpenMPDirectiveScope;
  SourceLocation Loc = ConsumeAnnotationToken(), EndLoc;
  OpenMPDirectiveKind DKind = parseOpenMPDirectiveKind(*this);
  OpenMPDirectiveKind CancelRegion = OMPD_unknown;
  // Name of critical directive.
  DeclarationNameInfo DirName;
  StmtResult Directive = StmtError();
  bool HasAssociatedStatement = true;

  switch (DKind) {
  case OMPD_threadprivate: {
    // FIXME: Should this be permitted in C++?
    if ((StmtCtx & ParsedStmtContext::AllowDeclarationsInC) ==
        ParsedStmtContext()) {
      Diag(Tok, diag::err_omp_immediate_directive)
          << getOpenMPDirectiveName(DKind) << 0;
    }
    ConsumeToken();
    DeclDirectiveListParserHelper Helper(this, DKind);
    if (!ParseOpenMPSimpleVarList(DKind, Helper,
                                  /*AllowScopeSpecifier=*/false)) {
      skipUntilPragmaOpenMPEnd(DKind);
      DeclGroupPtrTy Res = Actions.ActOnOpenMPThreadprivateDirective(
          Loc, Helper.getIdentifiers());
      Directive = Actions.ActOnDeclStmt(Res, Loc, Tok.getLocation());
    }
    SkipUntil(tok::annot_pragma_openmp_end);
    break;
  }
  case OMPD_allocate: {
    // FIXME: Should this be permitted in C++?
    if ((StmtCtx & ParsedStmtContext::AllowDeclarationsInC) ==
        ParsedStmtContext()) {
      Diag(Tok, diag::err_omp_immediate_directive)
          << getOpenMPDirectiveName(DKind) << 0;
    }
    ConsumeToken();
    DeclDirectiveListParserHelper Helper(this, DKind);
    if (!ParseOpenMPSimpleVarList(DKind, Helper,
                                  /*AllowScopeSpecifier=*/false)) {
      SmallVector<OMPClause *, 1> Clauses;
      if (Tok.isNot(tok::annot_pragma_openmp_end)) {
        SmallVector<llvm::PointerIntPair<OMPClause *, 1, bool>,
                    llvm::omp::Clause_enumSize + 1>
            FirstClauses(llvm::omp::Clause_enumSize + 1);
        while (Tok.isNot(tok::annot_pragma_openmp_end)) {
          OpenMPClauseKind CKind =
              Tok.isAnnotation() ? OMPC_unknown
                                 : getOpenMPClauseKind(PP.getSpelling(Tok));
          Actions.StartOpenMPClause(CKind);
          OMPClause *Clause = ParseOpenMPClause(
              OMPD_allocate, CKind, !FirstClauses[unsigned(CKind)].getInt());
          SkipUntil(tok::comma, tok::identifier, tok::annot_pragma_openmp_end,
                    StopBeforeMatch);
          FirstClauses[unsigned(CKind)].setInt(true);
          if (Clause != nullptr)
            Clauses.push_back(Clause);
          if (Tok.is(tok::annot_pragma_openmp_end)) {
            Actions.EndOpenMPClause();
            break;
          }
          // Skip ',' if any.
          if (Tok.is(tok::comma))
            ConsumeToken();
          Actions.EndOpenMPClause();
        }
        skipUntilPragmaOpenMPEnd(DKind);
      }
      DeclGroupPtrTy Res = Actions.ActOnOpenMPAllocateDirective(
          Loc, Helper.getIdentifiers(), Clauses);
      Directive = Actions.ActOnDeclStmt(Res, Loc, Tok.getLocation());
    }
    SkipUntil(tok::annot_pragma_openmp_end);
    break;
  }
  case OMPD_declare_reduction:
    ConsumeToken();
    if (DeclGroupPtrTy Res =
            ParseOpenMPDeclareReductionDirective(/*AS=*/AS_none)) {
      skipUntilPragmaOpenMPEnd(OMPD_declare_reduction);
      ConsumeAnyToken();
      Directive = Actions.ActOnDeclStmt(Res, Loc, Tok.getLocation());
    } else {
      SkipUntil(tok::annot_pragma_openmp_end);
    }
    break;
  case OMPD_declare_mapper: {
    ConsumeToken();
    if (DeclGroupPtrTy Res =
            ParseOpenMPDeclareMapperDirective(/*AS=*/AS_none)) {
      // Skip the last annot_pragma_openmp_end.
      ConsumeAnnotationToken();
      Directive = Actions.ActOnDeclStmt(Res, Loc, Tok.getLocation());
    } else {
      SkipUntil(tok::annot_pragma_openmp_end);
    }
    break;
  }
  case OMPD_flush:
  case OMPD_depobj:
  case OMPD_scan:
  case OMPD_taskyield:
  case OMPD_barrier:
  case OMPD_taskwait:
  case OMPD_cancellation_point:
  case OMPD_cancel:
  case OMPD_target_enter_data:
  case OMPD_target_exit_data:
  case OMPD_target_update:
    if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
        ParsedStmtContext()) {
      Diag(Tok, diag::err_omp_immediate_directive)
          << getOpenMPDirectiveName(DKind) << 0;
    }
    HasAssociatedStatement = false;
    // Fall through for further analysis.
    LLVM_FALLTHROUGH;
  case OMPD_parallel:
  case OMPD_simd:
  case OMPD_for:
  case OMPD_for_simd:
  case OMPD_sections:
  case OMPD_single:
  case OMPD_section:
  case OMPD_master:
  case OMPD_critical:
  case OMPD_parallel_for:
  case OMPD_parallel_for_simd:
  case OMPD_parallel_sections:
  case OMPD_parallel_master:
  case OMPD_task:
  case OMPD_ordered:
  case OMPD_atomic:
  case OMPD_target:
  case OMPD_teams:
  case OMPD_taskgroup:
  case OMPD_target_data:
  case OMPD_target_parallel:
  case OMPD_target_parallel_for:
  case OMPD_taskloop:
  case OMPD_taskloop_simd:
  case OMPD_master_taskloop:
  case OMPD_master_taskloop_simd:
  case OMPD_parallel_master_taskloop:
  case OMPD_parallel_master_taskloop_simd:
  case OMPD_distribute:
  case OMPD_distribute_parallel_for:
  case OMPD_distribute_parallel_for_simd:
  case OMPD_distribute_simd:
  case OMPD_target_parallel_for_simd:
  case OMPD_target_simd:
  case OMPD_teams_distribute:
  case OMPD_teams_distribute_simd:
  case OMPD_teams_distribute_parallel_for_simd:
  case OMPD_teams_distribute_parallel_for:
  case OMPD_target_teams:
  case OMPD_target_teams_distribute:
  case OMPD_target_teams_distribute_parallel_for:
  case OMPD_target_teams_distribute_parallel_for_simd:
  case OMPD_target_teams_distribute_simd: {
    // Special processing for flush and depobj clauses.
    Token ImplicitTok;
    bool ImplicitClauseAllowed = false;
    if (DKind == OMPD_flush || DKind == OMPD_depobj) {
      ImplicitTok = Tok;
      ImplicitClauseAllowed = true;
    }
    ConsumeToken();
    // Parse directive name of the 'critical' directive if any.
    if (DKind == OMPD_critical) {
      BalancedDelimiterTracker T(*this, tok::l_paren,
                                 tok::annot_pragma_openmp_end);
      if (!T.consumeOpen()) {
        if (Tok.isAnyIdentifier()) {
          DirName =
              DeclarationNameInfo(Tok.getIdentifierInfo(), Tok.getLocation());
          ConsumeAnyToken();
        } else {
          Diag(Tok, diag::err_omp_expected_identifier_for_critical);
        }
        T.consumeClose();
      }
    } else if (DKind == OMPD_cancellation_point || DKind == OMPD_cancel) {
      CancelRegion = parseOpenMPDirectiveKind(*this);
      if (Tok.isNot(tok::annot_pragma_openmp_end))
        ConsumeToken();
    }

    if (isOpenMPLoopDirective(DKind))
      ScopeFlags |= Scope::OpenMPLoopDirectiveScope;
    if (isOpenMPSimdDirective(DKind))
      ScopeFlags |= Scope::OpenMPSimdDirectiveScope;
    ParseScope OMPDirectiveScope(this, ScopeFlags);
    Actions.StartOpenMPDSABlock(DKind, DirName, Actions.getCurScope(), Loc);

    while (Tok.isNot(tok::annot_pragma_openmp_end)) {
      bool HasImplicitClause = false;
      if (ImplicitClauseAllowed && Tok.is(tok::l_paren)) {
        HasImplicitClause = true;
        // Push copy of the current token back to stream to properly parse
        // pseudo-clause OMPFlushClause or OMPDepobjClause.
        PP.EnterToken(Tok, /*IsReinject*/ true);
        PP.EnterToken(ImplicitTok, /*IsReinject*/ true);
        ConsumeAnyToken();
      }
      OpenMPClauseKind CKind = Tok.isAnnotation()
                                   ? OMPC_unknown
                                   : getOpenMPClauseKind(PP.getSpelling(Tok));
      if (HasImplicitClause) {
        assert(CKind == OMPC_unknown && "Must be unknown implicit clause.");
        if (DKind == OMPD_flush) {
          CKind = OMPC_flush;
        } else {
          assert(DKind == OMPD_depobj &&
                 "Expected flush or depobj directives.");
          CKind = OMPC_depobj;
        }
      }
      // No more implicit clauses allowed.
      ImplicitClauseAllowed = false;
      Actions.StartOpenMPClause(CKind);
      HasImplicitClause = false;
      OMPClause *Clause = ParseOpenMPClause(
          DKind, CKind, !FirstClauses[unsigned(CKind)].getInt());
      FirstClauses[unsigned(CKind)].setInt(true);
      if (Clause) {
        FirstClauses[unsigned(CKind)].setPointer(Clause);
        Clauses.push_back(Clause);
      }

      // Skip ',' if any.
      if (Tok.is(tok::comma))
        ConsumeToken();
      Actions.EndOpenMPClause();
    }
    // End location of the directive.
    EndLoc = Tok.getLocation();
    // Consume final annot_pragma_openmp_end.
    ConsumeAnnotationToken();

    // OpenMP [2.13.8, ordered Construct, Syntax]
    // If the depend clause is specified, the ordered construct is a stand-alone
    // directive.
    if (DKind == OMPD_ordered && FirstClauses[unsigned(OMPC_depend)].getInt()) {
      if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
          ParsedStmtContext()) {
        Diag(Loc, diag::err_omp_immediate_directive)
            << getOpenMPDirectiveName(DKind) << 1
            << getOpenMPClauseName(OMPC_depend);
      }
      HasAssociatedStatement = false;
    }

    StmtResult AssociatedStmt;
    if (HasAssociatedStatement) {
      // The body is a block scope like in Lambdas and Blocks.
      Actions.ActOnOpenMPRegionStart(DKind, getCurScope());
      // FIXME: We create a bogus CompoundStmt scope to hold the contents of
      // the captured region. Code elsewhere assumes that any FunctionScopeInfo
      // should have at least one compound statement scope within it.
      ParsingOpenMPDirectiveRAII NormalScope(*this, /*Value=*/false);
      AssociatedStmt = (Sema::CompoundScopeRAII(Actions), ParseStatement());
      AssociatedStmt = Actions.ActOnOpenMPRegionEnd(AssociatedStmt, Clauses);
    } else if (DKind == OMPD_target_update || DKind == OMPD_target_enter_data ||
               DKind == OMPD_target_exit_data) {
      Actions.ActOnOpenMPRegionStart(DKind, getCurScope());
      AssociatedStmt = (Sema::CompoundScopeRAII(Actions),
                        Actions.ActOnCompoundStmt(Loc, Loc, llvm::None,
                                                  /*isStmtExpr=*/false));
      AssociatedStmt = Actions.ActOnOpenMPRegionEnd(AssociatedStmt, Clauses);
    }
    Directive = Actions.ActOnOpenMPExecutableDirective(
        DKind, DirName, CancelRegion, Clauses, AssociatedStmt.get(), Loc,
        EndLoc);

    // Exit scope.
    Actions.EndOpenMPDSABlock(Directive.get());
    OMPDirectiveScope.Exit();
    break;
  }
  case OMPD_declare_simd:
  case OMPD_declare_target:
  case OMPD_end_declare_target:
  case OMPD_requires:
  case OMPD_begin_declare_variant:
  case OMPD_end_declare_variant:
  case OMPD_declare_variant:
    Diag(Tok, diag::err_omp_unexpected_directive)
        << 1 << getOpenMPDirectiveName(DKind);
    SkipUntil(tok::annot_pragma_openmp_end);
    break;
  case OMPD_unknown:
  default:
    Diag(Tok, diag::err_omp_unknown_directive);
    SkipUntil(tok::annot_pragma_openmp_end);
    break;
  }
  return Directive;
}

// Parses simple list:
//   simple-variable-list:
//         '(' id-expression {, id-expression} ')'
//
bool Parser::ParseOpenMPSimpleVarList(
    OpenMPDirectiveKind Kind,
    const llvm::function_ref<void(CXXScopeSpec &, DeclarationNameInfo)> &
        Callback,
    bool AllowScopeSpecifier) {
  // Parse '('.
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after,
                         getOpenMPDirectiveName(Kind).data()))
    return true;
  bool IsCorrect = true;
  bool NoIdentIsFound = true;

  // Read tokens while ')' or annot_pragma_openmp_end is not found.
  while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::annot_pragma_openmp_end)) {
    CXXScopeSpec SS;
    UnqualifiedId Name;
    // Read var name.
    Token PrevTok = Tok;
    NoIdentIsFound = false;

    if (AllowScopeSpecifier && getLangOpts().CPlusPlus &&
        ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
                                       /*ObjectHadErrors=*/false, false)) {
      IsCorrect = false;
      SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
    } else if (ParseUnqualifiedId(SS, /*ObjectType=*/nullptr,
                                  /*ObjectHadErrors=*/false, false, false,
                                  false, false, nullptr, Name)) {
      IsCorrect = false;
      SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
    } else if (Tok.isNot(tok::comma) && Tok.isNot(tok::r_paren) &&
               Tok.isNot(tok::annot_pragma_openmp_end)) {
      IsCorrect = false;
      SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
      Diag(PrevTok.getLocation(), diag::err_expected)
          << tok::identifier
          << SourceRange(PrevTok.getLocation(), PrevTokLocation);
    } else {
      Callback(SS, Actions.GetNameFromUnqualifiedId(Name));
    }
    // Consume ','.
    if (Tok.is(tok::comma)) {
      ConsumeToken();
    }
  }

  if (NoIdentIsFound) {
    Diag(Tok, diag::err_expected) << tok::identifier;
    IsCorrect = false;
  }

  // Parse ')'.
  IsCorrect = !T.consumeClose() && IsCorrect;

  return !IsCorrect;
}

OMPClause *Parser::ParseOpenMPUsesAllocatorClause(OpenMPDirectiveKind DKind) {
  SourceLocation Loc = Tok.getLocation();
  ConsumeAnyToken();

  // Parse '('.
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after, "uses_allocator"))
    return nullptr;
  SmallVector<Sema::UsesAllocatorsData, 4> Data;
  do {
    ExprResult Allocator = ParseCXXIdExpression();
    if (Allocator.isInvalid()) {
      SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                StopBeforeMatch);
      break;
    }
    Sema::UsesAllocatorsData &D = Data.emplace_back();
    D.Allocator = Allocator.get();
    if (Tok.is(tok::l_paren)) {
      BalancedDelimiterTracker T(*this, tok::l_paren,
                                 tok::annot_pragma_openmp_end);
      T.consumeOpen();
      ExprResult AllocatorTraits = ParseCXXIdExpression();
      T.consumeClose();
      if (AllocatorTraits.isInvalid()) {
        SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                  StopBeforeMatch);
        break;
      }
      D.AllocatorTraits = AllocatorTraits.get();
      D.LParenLoc = T.getOpenLocation();
      D.RParenLoc = T.getCloseLocation();
    }
    if (Tok.isNot(tok::comma) && Tok.isNot(tok::r_paren))
      Diag(Tok, diag::err_omp_expected_punc) << "uses_allocators" << 0;
    // Parse ','
    if (Tok.is(tok::comma))
      ConsumeAnyToken();
  } while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::annot_pragma_openmp_end));
  T.consumeClose();
  return Actions.ActOnOpenMPUsesAllocatorClause(Loc, T.getOpenLocation(),
                                                T.getCloseLocation(), Data);
}

/// Parsing of OpenMP clauses.
///
///    clause:
///       if-clause | final-clause | num_threads-clause | safelen-clause |
///       default-clause | private-clause | firstprivate-clause | shared-clause
///       | linear-clause | aligned-clause | collapse-clause |
///       lastprivate-clause | reduction-clause | proc_bind-clause |
///       schedule-clause | copyin-clause | copyprivate-clause | untied-clause |
///       mergeable-clause | flush-clause | read-clause | write-clause |
///       update-clause | capture-clause | seq_cst-clause | device-clause |
///       simdlen-clause | threads-clause | simd-clause | num_teams-clause |
///       thread_limit-clause | priority-clause | grainsize-clause |
///       nogroup-clause | num_tasks-clause | hint-clause | to-clause |
///       from-clause | is_device_ptr-clause | task_reduction-clause |
///       in_reduction-clause | allocator-clause | allocate-clause |
///       acq_rel-clause | acquire-clause | release-clause | relaxed-clause |
///       depobj-clause | destroy-clause | detach-clause | inclusive-clause |
///       exclusive-clause | uses_allocators-clause | use_device_addr-clause
///
OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
                                     OpenMPClauseKind CKind, bool FirstClause) {
  OMPClauseKind = CKind;
  OMPClause *Clause = nullptr;
  bool ErrorFound = false;
  bool WrongDirective = false;
  // Check if clause is allowed for the given directive.
  if (CKind != OMPC_unknown &&
      !isAllowedClauseForDirective(DKind, CKind, getLangOpts().OpenMP)) {
    Diag(Tok, diag::err_omp_unexpected_clause) << getOpenMPClauseName(CKind)
                                               << getOpenMPDirectiveName(DKind);
    ErrorFound = true;
    WrongDirective = true;
  }

  switch (CKind) {
  case OMPC_final:
  case OMPC_num_threads:
  case OMPC_safelen:
  case OMPC_simdlen:
  case OMPC_collapse:
  case OMPC_ordered:
  case OMPC_num_teams:
  case OMPC_thread_limit:
  case OMPC_priority:
  case OMPC_grainsize:
  case OMPC_num_tasks:
  case OMPC_hint:
  case OMPC_allocator:
  case OMPC_depobj:
  case OMPC_detach:
    // OpenMP [2.5, Restrictions]
    //  At most one num_threads clause can appear on the directive.
    // OpenMP [2.8.1, simd construct, Restrictions]
    //  Only one safelen  clause can appear on a simd directive.
    //  Only one simdlen  clause can appear on a simd directive.
    //  Only one collapse clause can appear on a simd directive.
    // OpenMP [2.11.1, task Construct, Restrictions]
    //  At most one if clause can appear on the directive.
    //  At most one final clause can appear on the directive.
    // OpenMP [teams Construct, Restrictions]
    //  At most one num_teams clause can appear on the directive.
    //  At most one thread_limit clause can appear on the directive.
    // OpenMP [2.9.1, task Construct, Restrictions]
    // At most one priority clause can appear on the directive.
    // OpenMP [2.9.2, taskloop Construct, Restrictions]
    // At most one grainsize clause can appear on the directive.
    // OpenMP [2.9.2, taskloop Construct, Restrictions]
    // At most one num_tasks clause can appear on the directive.
    // OpenMP [2.11.3, allocate Directive, Restrictions]
    // At most one allocator clause can appear on the directive.
    // OpenMP 5.0, 2.10.1 task Construct, Restrictions.
    // At most one detach clause can appear on the directive.
    if (!FirstClause) {
      Diag(Tok, diag::err_omp_more_one_clause)
          << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
      ErrorFound = true;
    }

    if (CKind == OMPC_ordered && PP.LookAhead(/*N=*/0).isNot(tok::l_paren))
      Clause = ParseOpenMPClause(CKind, WrongDirective);
    else
      Clause = ParseOpenMPSingleExprClause(CKind, WrongDirective);
    break;
  case OMPC_default:
  case OMPC_proc_bind:
  case OMPC_atomic_default_mem_order:
  case OMPC_order:
    // OpenMP [2.14.3.1, Restrictions]
    //  Only a single default clause may be specified on a parallel, task or
    //  teams directive.
    // OpenMP [2.5, parallel Construct, Restrictions]
    //  At most one proc_bind clause can appear on the directive.
    // OpenMP [5.0, Requires directive, Restrictions]
    //  At most one atomic_default_mem_order clause can appear
    //  on the directive
    if (!FirstClause && CKind != OMPC_order) {
      Diag(Tok, diag::err_omp_more_one_clause)
          << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
      ErrorFound = true;
    }

    Clause = ParseOpenMPSimpleClause(CKind, WrongDirective);
    break;
  case OMPC_device:
  case OMPC_schedule:
  case OMPC_dist_schedule:
  case OMPC_defaultmap:
    // OpenMP [2.7.1, Restrictions, p. 3]
    //  Only one schedule clause can appear on a loop directive.
    // OpenMP 4.5 [2.10.4, Restrictions, p. 106]
    //  At most one defaultmap clause can appear on the directive.
    // OpenMP 5.0 [2.12.5, target construct, Restrictions]
    //  At most one device clause can appear on the directive.
    if ((getLangOpts().OpenMP < 50 || CKind != OMPC_defaultmap) &&
        !FirstClause) {
      Diag(Tok, diag::err_omp_more_one_clause)
          << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
      ErrorFound = true;
    }
    LLVM_FALLTHROUGH;
  case OMPC_if:
    Clause = ParseOpenMPSingleExprWithArgClause(DKind, CKind, WrongDirective);
    break;
  case OMPC_nowait:
  case OMPC_untied:
  case OMPC_mergeable:
  case OMPC_read:
  case OMPC_write:
  case OMPC_capture:
  case OMPC_seq_cst:
  case OMPC_acq_rel:
  case OMPC_acquire:
  case OMPC_release:
  case OMPC_relaxed:
  case OMPC_threads:
  case OMPC_simd:
  case OMPC_nogroup:
  case OMPC_unified_address:
  case OMPC_unified_shared_memory:
  case OMPC_reverse_offload:
  case OMPC_dynamic_allocators:
  case OMPC_destroy:
    // OpenMP [2.7.1, Restrictions, p. 9]
    //  Only one ordered clause can appear on a loop directive.
    // OpenMP [2.7.1, Restrictions, C/C++, p. 4]
    //  Only one nowait clause can appear on a for directive.
    // OpenMP [5.0, Requires directive, Restrictions]
    //   Each of the requires clauses can appear at most once on the directive.
    if (!FirstClause) {
      Diag(Tok, diag::err_omp_more_one_clause)
          << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
      ErrorFound = true;
    }

    Clause = ParseOpenMPClause(CKind, WrongDirective);
    break;
  case OMPC_update:
    if (!FirstClause) {
      Diag(Tok, diag::err_omp_more_one_clause)
          << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
      ErrorFound = true;
    }

    Clause = (DKind == OMPD_depobj)
                 ? ParseOpenMPSimpleClause(CKind, WrongDirective)
                 : ParseOpenMPClause(CKind, WrongDirective);
    break;
  case OMPC_private:
  case OMPC_firstprivate:
  case OMPC_lastprivate:
  case OMPC_shared:
  case OMPC_reduction:
  case OMPC_task_reduction:
  case OMPC_in_reduction:
  case OMPC_linear:
  case OMPC_aligned:
  case OMPC_copyin:
  case OMPC_copyprivate:
  case OMPC_flush:
  case OMPC_depend:
  case OMPC_map:
  case OMPC_to:
  case OMPC_from:
  case OMPC_use_device_ptr:
  case OMPC_use_device_addr:
  case OMPC_is_device_ptr:
  case OMPC_allocate:
  case OMPC_nontemporal:
  case OMPC_inclusive:
  case OMPC_exclusive:
  case OMPC_affinity:
    Clause = ParseOpenMPVarListClause(DKind, CKind, WrongDirective);
    break;
  case OMPC_uses_allocators:
    Clause = ParseOpenMPUsesAllocatorClause(DKind);
    break;
  case OMPC_device_type:
  case OMPC_unknown:
    skipUntilPragmaOpenMPEnd(DKind);
    break;
  case OMPC_threadprivate:
  case OMPC_uniform:
  case OMPC_match:
    if (!WrongDirective)
      Diag(Tok, diag::err_omp_unexpected_clause)
          << getOpenMPClauseName(CKind) << getOpenMPDirectiveName(DKind);
    SkipUntil(tok::comma, tok::annot_pragma_openmp_end, StopBeforeMatch);
    break;
  default:
    break;
  }
  return ErrorFound ? nullptr : Clause;
}

/// Parses simple expression in parens for single-expression clauses of OpenMP
/// constructs.
/// \param RLoc Returned location of right paren.
ExprResult Parser::ParseOpenMPParensExpr(StringRef ClauseName,
                                         SourceLocation &RLoc,
                                         bool IsAddressOfOperand) {
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after, ClauseName.data()))
    return ExprError();

  SourceLocation ELoc = Tok.getLocation();
  ExprResult LHS(ParseCastExpression(AnyCastExpr, IsAddressOfOperand,
                                     NotTypeCast));
  ExprResult Val(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
  Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);

  // Parse ')'.
  RLoc = Tok.getLocation();
  if (!T.consumeClose())
    RLoc = T.getCloseLocation();

  return Val;