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

#include "resolve-directives.h"

#include "check-acc-structure.h"
#include "check-omp-structure.h"
#include "resolve-names-utils.h"
#include "flang/Common/idioms.h"
#include "flang/Evaluate/fold.h"
#include "flang/Evaluate/type.h"
#include "flang/Parser/parse-tree-visitor.h"
#include "flang/Parser/parse-tree.h"
#include "flang/Parser/tools.h"
#include "flang/Semantics/expression.h"
#include <list>
#include <map>

namespace Fortran::semantics {

template <typename T> class DirectiveAttributeVisitor {
public:
  explicit DirectiveAttributeVisitor(SemanticsContext &context)
      : context_{context} {}

  template <typename A> bool Pre(const A &) { return true; }
  template <typename A> void Post(const A &) {}

protected:
  struct DirContext {
    DirContext(const parser::CharBlock &source, T d, Scope &s)
        : directiveSource{source}, directive{d}, scope{s} {}
    parser::CharBlock directiveSource;
    T directive;
    Scope &scope;
    Symbol::Flag defaultDSA{Symbol::Flag::AccShared}; // TODOACC
    std::map<const Symbol *, Symbol::Flag> objectWithDSA;
    bool withinConstruct{false};
    std::int64_t associatedLoopLevel{0};
  };

  DirContext &GetContext() {
    CHECK(!dirContext_.empty());
    return dirContext_.back();
  }
  std::optional<DirContext> GetContextIf() {
    return dirContext_.empty()
        ? std::nullopt
        : std::make_optional<DirContext>(dirContext_.back());
  }
  void PushContext(const parser::CharBlock &source, T dir) {
    dirContext_.emplace_back(source, dir, context_.FindScope(source));
  }
  void PopContext() { dirContext_.pop_back(); }
  void SetContextDirectiveSource(parser::CharBlock &dir) {
    GetContext().directiveSource = dir;
  }
  Scope &currScope() { return GetContext().scope; }
  void SetContextDefaultDSA(Symbol::Flag flag) {
    GetContext().defaultDSA = flag;
  }
  void AddToContextObjectWithDSA(
      const Symbol &symbol, Symbol::Flag flag, DirContext &context) {
    context.objectWithDSA.emplace(&symbol, flag);
  }
  void AddToContextObjectWithDSA(const Symbol &symbol, Symbol::Flag flag) {
    AddToContextObjectWithDSA(symbol, flag, GetContext());
  }
  bool IsObjectWithDSA(const Symbol &symbol) {
    auto it{GetContext().objectWithDSA.find(&symbol)};
    return it != GetContext().objectWithDSA.end();
  }
  void SetContextAssociatedLoopLevel(std::int64_t level) {
    GetContext().associatedLoopLevel = level;
  }
  Symbol &MakeAssocSymbol(const SourceName &name, Symbol &prev, Scope &scope) {
    const auto pair{scope.try_emplace(name, Attrs{}, HostAssocDetails{prev})};
    return *pair.first->second;
  }
  Symbol &MakeAssocSymbol(const SourceName &name, Symbol &prev) {
    return MakeAssocSymbol(name, prev, currScope());
  }
  static const parser::Name *GetDesignatorNameIfDataRef(
      const parser::Designator &designator) {
    const auto *dataRef{std::get_if<parser::DataRef>(&designator.u)};
    return dataRef ? std::get_if<parser::Name>(&dataRef->u) : nullptr;
  }
  void AddDataSharingAttributeObject(SymbolRef object) {
    dataSharingAttributeObjects_.insert(object);
  }
  void ClearDataSharingAttributeObjects() {
    dataSharingAttributeObjects_.clear();
  }
  bool HasDataSharingAttributeObject(const Symbol &);
  const parser::Name &GetLoopIndex(const parser::DoConstruct &);
  const parser::DoConstruct *GetDoConstructIf(
      const parser::ExecutionPartConstruct &);
  Symbol *DeclarePrivateAccessEntity(
      const parser::Name &, Symbol::Flag, Scope &);
  Symbol *DeclarePrivateAccessEntity(Symbol &, Symbol::Flag, Scope &);
  Symbol *DeclareOrMarkOtherAccessEntity(const parser::Name &, Symbol::Flag);

  UnorderedSymbolSet dataSharingAttributeObjects_; // on one directive
  SemanticsContext &context_;
  std::vector<DirContext> dirContext_; // used as a stack
};

class AccAttributeVisitor : DirectiveAttributeVisitor<llvm::acc::Directive> {
public:
  explicit AccAttributeVisitor(SemanticsContext &context)
      : DirectiveAttributeVisitor(context) {}

  template <typename A> void Walk(const A &x) { parser::Walk(x, *this); }
  template <typename A> bool Pre(const A &) { return true; }
  template <typename A> void Post(const A &) {}

  bool Pre(const parser::OpenACCBlockConstruct &);
  void Post(const parser::OpenACCBlockConstruct &) { PopContext(); }
  bool Pre(const parser::OpenACCCombinedConstruct &);
  void Post(const parser::OpenACCCombinedConstruct &) { PopContext(); }

  bool Pre(const parser::OpenACCDeclarativeConstruct &);
  void Post(const parser::OpenACCDeclarativeConstruct &) { PopContext(); }

  bool Pre(const parser::OpenACCRoutineConstruct &);
  bool Pre(const parser::AccBindClause &);
  void Post(const parser::OpenACCStandaloneDeclarativeConstruct &);

  void Post(const parser::AccBeginBlockDirective &) {
    GetContext().withinConstruct = true;
  }

  bool Pre(const parser::OpenACCLoopConstruct &);
  void Post(const parser::OpenACCLoopConstruct &) { PopContext(); }
  void Post(const parser::AccLoopDirective &) {
    GetContext().withinConstruct = true;
  }

  bool Pre(const parser::OpenACCStandaloneConstruct &);
  void Post(const parser::OpenACCStandaloneConstruct &) { PopContext(); }
  void Post(const parser::AccStandaloneDirective &) {
    GetContext().withinConstruct = true;
  }

  bool Pre(const parser::OpenACCCacheConstruct &);
  void Post(const parser::OpenACCCacheConstruct &) { PopContext(); }

  void Post(const parser::AccDefaultClause &);

  bool Pre(const parser::AccClause::Copy &x) {
    ResolveAccObjectList(x.v, Symbol::Flag::AccCopyIn);
    ResolveAccObjectList(x.v, Symbol::Flag::AccCopyOut);
    return false;
  }

  bool Pre(const parser::AccClause::Create &x) {
    const auto &objectList{std::get<parser::AccObjectList>(x.v.t)};
    ResolveAccObjectList(objectList, Symbol::Flag::AccCreate);
    return false;
  }

  bool Pre(const parser::AccClause::Copyin &x) {
    const auto &objectList{std::get<parser::AccObjectList>(x.v.t)};
    ResolveAccObjectList(objectList, Symbol::Flag::AccCopyIn);
    return false;
  }

  bool Pre(const parser::AccClause::Copyout &x) {
    const auto &objectList{std::get<parser::AccObjectList>(x.v.t)};
    ResolveAccObjectList(objectList, Symbol::Flag::AccCopyOut);
    return false;
  }

  bool Pre(const parser::AccClause::Present &x) {
    ResolveAccObjectList(x.v, Symbol::Flag::AccPresent);
    return false;
  }
  bool Pre(const parser::AccClause::Private &x) {
    ResolveAccObjectList(x.v, Symbol::Flag::AccPrivate);
    return false;
  }
  bool Pre(const parser::AccClause::Firstprivate &x) {
    ResolveAccObjectList(x.v, Symbol::Flag::AccFirstPrivate);
    return false;
  }

  void Post(const parser::Name &);

private:
  std::int64_t GetAssociatedLoopLevelFromClauses(const parser::AccClauseList &);

  static constexpr Symbol::Flags dataSharingAttributeFlags{
      Symbol::Flag::AccShared, Symbol::Flag::AccPrivate,
      Symbol::Flag::AccPresent, Symbol::Flag::AccFirstPrivate,
      Symbol::Flag::AccReduction};

  static constexpr Symbol::Flags dataMappingAttributeFlags{
      Symbol::Flag::AccCreate, Symbol::Flag::AccCopyIn,
      Symbol::Flag::AccCopyOut, Symbol::Flag::AccDelete};

  static constexpr Symbol::Flags accFlagsRequireNewSymbol{
      Symbol::Flag::AccPrivate, Symbol::Flag::AccFirstPrivate,
      Symbol::Flag::AccReduction};

  static constexpr Symbol::Flags accFlagsRequireMark{};

  void PrivatizeAssociatedLoopIndex(const parser::OpenACCLoopConstruct &);
  void ResolveAccObjectList(const parser::AccObjectList &, Symbol::Flag);
  void ResolveAccObject(const parser::AccObject &, Symbol::Flag);
  Symbol *ResolveAcc(const parser::Name &, Symbol::Flag, Scope &);
  Symbol *ResolveAcc(Symbol &, Symbol::Flag, Scope &);
  Symbol *ResolveName(const parser::Name &);
  Symbol *ResolveAccCommonBlockName(const parser::Name *);
  Symbol *DeclareOrMarkOtherAccessEntity(const parser::Name &, Symbol::Flag);
  Symbol *DeclareOrMarkOtherAccessEntity(Symbol &, Symbol::Flag);
  void CheckMultipleAppearances(
      const parser::Name &, const Symbol &, Symbol::Flag);
  void AllowOnlyArrayAndSubArray(const parser::AccObjectList &objectList);
  void DoNotAllowAssumedSizedArray(const parser::AccObjectList &objectList);
};

// Data-sharing and Data-mapping attributes for data-refs in OpenMP construct
class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
public:
  explicit OmpAttributeVisitor(SemanticsContext &context)
      : DirectiveAttributeVisitor(context) {}

  template <typename A> void Walk(const A &x) { parser::Walk(x, *this); }
  template <typename A> bool Pre(const A &) { return true; }
  template <typename A> void Post(const A &) {}

  template <typename A> bool Pre(const parser::Statement<A> &statement) {
    currentStatementSource_ = statement.source;
    // Keep track of the labels in all the labelled statements
    if (statement.label) {
      auto label{statement.label.value()};
      // Get the context to check if the labelled statement is in an
      // enclosing OpenMP construct
      std::optional<DirContext> thisContext{GetContextIf()};
      targetLabels_.emplace(
          label, std::make_pair(currentStatementSource_, thisContext));
      // Check if a statement that causes a jump to the 'label'
      // has already been encountered
      auto range{sourceLabels_.equal_range(label)};
      for (auto it{range.first}; it != range.second; ++it) {
        // Check if both the statement with 'label' and the statement that
        // causes a jump to the 'label' are in the same scope
        CheckLabelContext(it->second.first, currentStatementSource_,
            it->second.second, thisContext);
      }
    }
    return true;
  }

  bool Pre(const parser::InternalSubprogram &) {
    // Clear the labels being tracked in the previous scope
    ClearLabels();
    return true;
  }

  bool Pre(const parser::ModuleSubprogram &) {
    // Clear the labels being tracked in the previous scope
    ClearLabels();
    return true;
  }

  bool Pre(const parser::SpecificationPart &x) {
    Walk(std::get<std::list<parser::OpenMPDeclarativeConstruct>>(x.t));
    return true;
  }

  bool Pre(const parser::StmtFunctionStmt &x) {
    const auto &parsedExpr{std::get<parser::Scalar<parser::Expr>>(x.t)};
    if (const auto *expr{GetExpr(parsedExpr)}) {
      for (const Symbol &symbol : evaluate::CollectSymbols(*expr)) {
        if (!IsStmtFunctionDummy(symbol)) {
          stmtFunctionExprSymbols_.insert(symbol.GetUltimate());
        }
      }
    }
    return true;
  }

  bool Pre(const parser::OpenMPBlockConstruct &);
  void Post(const parser::OpenMPBlockConstruct &);

  void Post(const parser::OmpBeginBlockDirective &) {
    GetContext().withinConstruct = true;
  }

  bool Pre(const parser::OpenMPLoopConstruct &);
  void Post(const parser::OpenMPLoopConstruct &) { PopContext(); }
  void Post(const parser::OmpBeginLoopDirective &) {
    GetContext().withinConstruct = true;
  }
  bool Pre(const parser::DoConstruct &);

  bool Pre(const parser::OpenMPSectionsConstruct &);
  void Post(const parser::OpenMPSectionsConstruct &) { PopContext(); }

  bool Pre(const parser::OpenMPCriticalConstruct &);
  void Post(const parser::OpenMPCriticalConstruct &) { PopContext(); }

  bool Pre(const parser::OpenMPDeclareSimdConstruct &x) {
    PushContext(x.source, llvm::omp::Directive::OMPD_declare_simd);
    const auto &name{std::get<std::optional<parser::Name>>(x.t)};
    if (name) {
      ResolveOmpName(*name, Symbol::Flag::OmpDeclareSimd);
    }
    return true;
  }
  void Post(const parser::OpenMPDeclareSimdConstruct &) { PopContext(); }
  bool Pre(const parser::OpenMPThreadprivate &);
  void Post(const parser::OpenMPThreadprivate &) { PopContext(); }

  // 2.15.3 Data-Sharing Attribute Clauses
  void Post(const parser::OmpDefaultClause &);
  bool Pre(const parser::OmpClause::Shared &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpShared);
    return false;
  }
  bool Pre(const parser::OmpClause::Private &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpPrivate);
    return false;
  }
  bool Pre(const parser::OmpAllocateClause &x) {
    const auto &objectList{std::get<parser::OmpObjectList>(x.t)};
    ResolveOmpObjectList(objectList, Symbol::Flag::OmpAllocate);
    return false;
  }
  bool Pre(const parser::OmpClause::Firstprivate &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpFirstPrivate);
    return false;
  }
  bool Pre(const parser::OmpClause::Lastprivate &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpLastPrivate);
    return false;
  }
  bool Pre(const parser::OmpClause::Copyin &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpCopyIn);
    return false;
  }
  bool Pre(const parser::OmpClause::Copyprivate &x) {
    ResolveOmpObjectList(x.v, Symbol::Flag::OmpCopyPrivate);
    return false;
  }
  bool Pre(const parser::OmpLinearClause &x) {
    std::visit(common::visitors{
                   [&](const parser::OmpLinearClause::WithoutModifier
                           &linearWithoutModifier) {
                     ResolveOmpNameList(
                         linearWithoutModifier.names, Symbol::Flag::OmpLinear);
                   },
                   [&](const parser::OmpLinearClause::WithModifier
                           &linearWithModifier) {
                     ResolveOmpNameList(
                         linearWithModifier.names, Symbol::Flag::OmpLinear);
                   },
               },
        x.u);
    return false;
  }

  bool Pre(const parser::OmpClause::Reduction &x) {
    const parser::OmpReductionOperator &opr{
        std::get<parser::OmpReductionOperator>(x.v.t)};
    if (const auto *procD{parser::Unwrap<parser::ProcedureDesignator>(opr.u)}) {
      if (const auto *name{parser::Unwrap<parser::Name>(procD->u)}) {
        if (!name->symbol) {
          const auto namePair{currScope().try_emplace(
              name->source, Attrs{}, ProcEntityDetails{})};
          auto &symbol{*namePair.first->second};
          name->symbol = &symbol;
          name->symbol->set(Symbol::Flag::OmpReduction);
          AddToContextObjectWithDSA(*name->symbol, Symbol::Flag::OmpReduction);
        }
      }
      if (const auto *procRef{
              parser::Unwrap<parser::ProcComponentRef>(procD->u)}) {
        ResolveOmp(*procRef->v.thing.component.symbol,
            Symbol::Flag::OmpReduction, currScope());
      }
    }
    const auto &objList{std::get<parser::OmpObjectList>(x.v.t)};
    ResolveOmpObjectList(objList, Symbol::Flag::OmpReduction);
    return false;
  }

  bool Pre(const parser::OmpAlignedClause &x) {
    const auto &alignedNameList{std::get<std::list<parser::Name>>(x.t)};
    ResolveOmpNameList(alignedNameList, Symbol::Flag::OmpAligned);
    return false;
  }
  void Post(const parser::Name &);

  // Keep track of labels in the statements that causes jumps to target labels
  void Post(const parser::GotoStmt &gotoStmt) { CheckSourceLabel(gotoStmt.v); }
  void Post(const parser::ComputedGotoStmt &computedGotoStmt) {
    for (auto &label : std::get<std::list<parser::Label>>(computedGotoStmt.t)) {
      CheckSourceLabel(label);
    }
  }
  void Post(const parser::ArithmeticIfStmt &arithmeticIfStmt) {
    CheckSourceLabel(std::get<1>(arithmeticIfStmt.t));
    CheckSourceLabel(std::get<2>(arithmeticIfStmt.t));
    CheckSourceLabel(std::get<3>(arithmeticIfStmt.t));
  }
  void Post(const parser::AssignedGotoStmt &assignedGotoStmt) {
    for (auto &label : std::get<std::list<parser::Label>>(assignedGotoStmt.t)) {
      CheckSourceLabel(label);
    }
  }
  void Post(const parser::AltReturnSpec &altReturnSpec) {
    CheckSourceLabel(altReturnSpec.v);
  }
  void Post(const parser::ErrLabel &errLabel) { CheckSourceLabel(errLabel.v); }
  void Post(const parser::EndLabel &endLabel) { CheckSourceLabel(endLabel.v); }
  void Post(const parser::EorLabel &eorLabel) { CheckSourceLabel(eorLabel.v); }

  const parser::OmpClause *associatedClause{nullptr};
  void SetAssociatedClause(const parser::OmpClause &c) {
    associatedClause = &c;
  }
  const parser::OmpClause *GetAssociatedClause() { return associatedClause; }

private:
  std::int64_t GetAssociatedLoopLevelFromClauses(const parser::OmpClauseList &);

  static constexpr Symbol::Flags dataSharingAttributeFlags{
      Symbol::Flag::OmpShared, Symbol::Flag::OmpPrivate,
      Symbol::Flag::OmpFirstPrivate, Symbol::Flag::OmpLastPrivate,
      Symbol::Flag::OmpReduction, Symbol::Flag::OmpLinear};

  static constexpr Symbol::Flags privateDataSharingAttributeFlags{
      Symbol::Flag::OmpPrivate, Symbol::Flag::OmpFirstPrivate,
      Symbol::Flag::OmpLastPrivate};

  static constexpr Symbol::Flags ompFlagsRequireNewSymbol{
      Symbol::Flag::OmpPrivate, Symbol::Flag::OmpLinear,
      Symbol::Flag::OmpFirstPrivate, Symbol::Flag::OmpLastPrivate,
      Symbol::Flag::OmpReduction};

  static constexpr Symbol::Flags ompFlagsRequireMark{
      Symbol::Flag::OmpThreadprivate};

  static constexpr Symbol::Flags dataCopyingAttributeFlags{
      Symbol::Flag::OmpCopyIn, Symbol::Flag::OmpCopyPrivate};

  std::vector<const parser::Name *> allocateNames_; // on one directive
  UnorderedSymbolSet privateDataSharingAttributeObjects_; // on one directive
  UnorderedSymbolSet stmtFunctionExprSymbols_;
  std::multimap<const parser::Label,
      std::pair<parser::CharBlock, std::optional<DirContext>>>
      sourceLabels_;
  std::map<const parser::Label,
      std::pair<parser::CharBlock, std::optional<DirContext>>>
      targetLabels_;
  parser::CharBlock currentStatementSource_;

  void AddAllocateName(const parser::Name *&object) {
    allocateNames_.push_back(object);
  }
  void ClearAllocateNames() { allocateNames_.clear(); }

  void AddPrivateDataSharingAttributeObjects(SymbolRef object) {
    privateDataSharingAttributeObjects_.insert(object);
  }
  void ClearPrivateDataSharingAttributeObjects() {
    privateDataSharingAttributeObjects_.clear();
  }

  // Predetermined DSA rules
  void PrivatizeAssociatedLoopIndexAndCheckLoopLevel(
      const parser::OpenMPLoopConstruct &);
  void ResolveSeqLoopIndexInParallelOrTaskConstruct(const parser::Name &);

  void ResolveOmpObjectList(const parser::OmpObjectList &, Symbol::Flag);
  void ResolveOmpObject(const parser::OmpObject &, Symbol::Flag);
  Symbol *ResolveOmp(const parser::Name &, Symbol::Flag, Scope &);
  Symbol *ResolveOmp(Symbol &, Symbol::Flag, Scope &);
  Symbol *ResolveOmpCommonBlockName(const parser::Name *);
  void ResolveOmpNameList(const std::list<parser::Name> &, Symbol::Flag);
  void ResolveOmpName(const parser::Name &, Symbol::Flag);
  Symbol *ResolveName(const parser::Name *);
  Symbol *DeclareOrMarkOtherAccessEntity(const parser::Name &, Symbol::Flag);
  Symbol *DeclareOrMarkOtherAccessEntity(Symbol &, Symbol::Flag);
  void CheckMultipleAppearances(
      const parser::Name &, const Symbol &, Symbol::Flag);

  void CheckDataCopyingClause(
      const parser::Name &, const Symbol &, Symbol::Flag);
  void CheckAssocLoopLevel(std::int64_t level, const parser::OmpClause *clause);
  void CheckPrivateDSAObject(
      const parser::Name &, const Symbol &, Symbol::Flag);
  void CheckSourceLabel(const parser::Label &);
  void CheckLabelContext(const parser::CharBlock, const parser::CharBlock,
      std::optional<DirContext>, std::optional<DirContext>);
  void ClearLabels() {
    sourceLabels_.clear();
    targetLabels_.clear();
  };

  bool HasSymbolInEnclosingScope(const Symbol &, Scope &);
  std::int64_t ordCollapseLevel{0};
};

template <typename T>
bool DirectiveAttributeVisitor<T>::HasDataSharingAttributeObject(
    const Symbol &object) {
  auto it{dataSharingAttributeObjects_.find(object)};
  return it != dataSharingAttributeObjects_.end();
}

template <typename T>
const parser::Name &DirectiveAttributeVisitor<T>::GetLoopIndex(
    const parser::DoConstruct &x) {
  using Bounds = parser::LoopControl::Bounds;
  return std::get<Bounds>(x.GetLoopControl()->u).name.thing;
}

template <typename T>
const parser::DoConstruct *DirectiveAttributeVisitor<T>::GetDoConstructIf(
    const parser::ExecutionPartConstruct &x) {
  return parser::Unwrap<parser::DoConstruct>(x);
}

template <typename T>
Symbol *DirectiveAttributeVisitor<T>::DeclarePrivateAccessEntity(
    const parser::Name &name, Symbol::Flag flag, Scope &scope) {
  if (!name.symbol) {
    return nullptr; // not resolved by Name Resolution step, do nothing
  }
  name.symbol = DeclarePrivateAccessEntity(*name.symbol, flag, scope);
  return name.symbol;
}

template <typename T>
Symbol *DirectiveAttributeVisitor<T>::DeclarePrivateAccessEntity(
    Symbol &object, Symbol::Flag flag, Scope &scope) {
  if (object.owner() != currScope()) {
    auto &symbol{MakeAssocSymbol(object.name(), object, scope)};
    symbol.set(flag);
    return &symbol;
  } else {
    object.set(flag);
    return &object;
  }
}

bool AccAttributeVisitor::Pre(const parser::OpenACCBlockConstruct &x) {
  const auto &beginBlockDir{std::get<parser::AccBeginBlockDirective>(x.t)};
  const auto &blockDir{std::get<parser::AccBlockDirective>(beginBlockDir.t)};
  switch (blockDir.v) {
  case llvm::acc::Directive::ACCD_data:
  case llvm::acc::Directive::ACCD_host_data:
  case llvm::acc::Directive::ACCD_kernels:
  case llvm::acc::Directive::ACCD_parallel:
  case llvm::acc::Directive::ACCD_serial:
    PushContext(blockDir.source, blockDir.v);
    break;
  default:
    break;
  }
  ClearDataSharingAttributeObjects();
  return true;
}

bool AccAttributeVisitor::Pre(const parser::OpenACCDeclarativeConstruct &x) {
  if (const auto *declConstruct{
          std::get_if<parser::OpenACCStandaloneDeclarativeConstruct>(&x.u)}) {
    const auto &declDir{
        std::get<parser::AccDeclarativeDirective>(declConstruct->t)};
    PushContext(declDir.source, llvm::acc::Directive::ACCD_declare);
  } else if (const auto *routineConstruct{
                 std::get_if<parser::OpenACCRoutineConstruct>(&x.u)}) {
    const auto &verbatim{std::get<parser::Verbatim>(routineConstruct->t)};
    PushContext(verbatim.source, llvm::acc::Directive::ACCD_routine);
  }
  ClearDataSharingAttributeObjects();
  return true;
}

static const parser::AccObjectList &GetAccObjectList(
    const parser::AccClause &clause) {
  if (const auto *copyClause =
          std::get_if<Fortran::parser::AccClause::Copy>(&clause.u)) {
    return copyClause->v;
  } else if (const auto *createClause =
                 std::get_if<Fortran::parser::AccClause::Create>(&clause.u)) {
    const Fortran::parser::AccObjectListWithModifier &listWithModifier =
        createClause->v;
    const Fortran::parser::AccObjectList &accObjectList =
        std::get<Fortran::parser::AccObjectList>(listWithModifier.t);
    return accObjectList;
  } else if (const auto *copyinClause =
                 std::get_if<Fortran::parser::AccClause::Copyin>(&clause.u)) {
    const Fortran::parser::AccObjectListWithModifier &listWithModifier =
        copyinClause->v;
    const Fortran::parser::AccObjectList &accObjectList =
        std::get<Fortran::parser::AccObjectList>(listWithModifier.t);
    return accObjectList;
  } else if (const auto *copyoutClause =
                 std::get_if<Fortran::parser::AccClause::Copyout>(&clause.u)) {
    const Fortran::parser::AccObjectListWithModifier &listWithModifier =
        copyoutClause->v;
    const Fortran::parser::AccObjectList &accObjectList =
        std::get<Fortran::parser::AccObjectList>(listWithModifier.t);
    return accObjectList;
  } else if (const auto *presentClause =
                 std::get_if<Fortran::parser::AccClause::Present>(&clause.u)) {
    return presentClause->v;
  } else if (const auto *deviceptrClause =
                 std::get_if<Fortran::parser::AccClause::Deviceptr>(
                     &clause.u)) {
    return deviceptrClause->v;
  } else if (const auto *deviceResidentClause =
                 std::get_if<Fortran::parser::AccClause::DeviceResident>(
                     &clause.u)) {
    return deviceResidentClause->v;
  } else if (const auto *linkClause =
                 std::get_if<Fortran::parser::AccClause::Link>(&clause.u)) {
    return linkClause->v;
  } else {
    llvm_unreachable("Clause without object list!");
  }
}

void AccAttributeVisitor::Post(
    const parser::OpenACCStandaloneDeclarativeConstruct &x) {
  const auto &clauseList = std::get<parser::AccClauseList>(x.t);
  for (const auto &clause : clauseList.v) {
    // Restriction - line 2414
    DoNotAllowAssumedSizedArray(GetAccObjectList(clause));
  }
}

bool AccAttributeVisitor::Pre(const parser::OpenACCLoopConstruct &x) {
  const auto &beginDir{std::get<parser::AccBeginLoopDirective>(x.t)};
  const auto &loopDir{std::get<parser::AccLoopDirective>(beginDir.t)};
  const auto &clauseList{std::get<parser::AccClauseList>(beginDir.t)};
  if (loopDir.v == llvm::acc::Directive::ACCD_loop) {
    PushContext(loopDir.source, loopDir.v);
  }
  ClearDataSharingAttributeObjects();
  SetContextAssociatedLoopLevel(GetAssociatedLoopLevelFromClauses(clauseList));
  PrivatizeAssociatedLoopIndex(x);
  return true;
}

bool AccAttributeVisitor::Pre(const parser::OpenACCStandaloneConstruct &x) {
  const auto &standaloneDir{std::get<parser::AccStandaloneDirective>(x.t)};
  switch (standaloneDir.v) {
  case llvm::acc::Directive::ACCD_enter_data:
  case llvm::acc::Directive::ACCD_exit_data:
  case llvm::acc::Directive::ACCD_init:
  case llvm::acc::Directive::ACCD_set:
  case llvm::acc::Directive::ACCD_shutdown:
  case llvm::acc::Directive::ACCD_update:
    PushContext(standaloneDir.source, standaloneDir.v);
    break;
  default:
    break;
  }
  ClearDataSharingAttributeObjects();
  return true;
}

Symbol *AccAttributeVisitor::ResolveName(const parser::Name &name) {
  Symbol *prev{currScope().FindSymbol(name.source)};
  if (prev != name.symbol) {
    name.symbol = prev;
  }
  return prev;
}

bool AccAttributeVisitor::Pre(const parser::OpenACCRoutineConstruct &x) {
  const auto &optName{std::get<std::optional<parser::Name>>(x.t)};
  if (optName) {
    if (!ResolveName(*optName))
      context_.Say((*optName).source,
          "No function or subroutine declared for '%s'"_err_en_US,
          (*optName).source);
  }
  return true;
}

bool AccAttributeVisitor::Pre(const parser::AccBindClause &x) {
  if (const auto *name{std::get_if<parser::Name>(&x.u)}) {
    if (!ResolveName(*name))
      context_.Say(name->source,
          "No function or subroutine declared for '%s'"_err_en_US,
          name->source);
  }
  return true;
}

bool AccAttributeVisitor::Pre(const parser::OpenACCCombinedConstruct &x) {
  const auto &beginBlockDir{std::get<parser::AccBeginCombinedDirective>(x.t)};
  const auto &combinedDir{
      std::get<parser::AccCombinedDirective>(beginBlockDir.t)};
  switch (combinedDir.v) {
  case llvm::acc::Directive::ACCD_kernels_loop:
  case llvm::acc::Directive::ACCD_parallel_loop:
  case llvm::acc::Directive::ACCD_serial_loop:
    PushContext(combinedDir.source, combinedDir.v);
    break;
  default:
    break;
  }
  ClearDataSharingAttributeObjects();
  return true;
}

static bool IsLastNameArray(const parser::Designator &designator) {
  const auto &name{GetLastName(designator)};
  const evaluate::DataRef dataRef{*(name.symbol)};
  return std::visit(
      common::visitors{
          [](const evaluate::SymbolRef &ref) { return ref->Rank() > 0; },
          [](const evaluate::ArrayRef &aref) {
            return aref.base().IsSymbol() ||
                aref.base().GetComponent().base().Rank() == 0;
          },
          [](const auto &) { return false; },
      },
      dataRef.u);
}

void AccAttributeVisitor::AllowOnlyArrayAndSubArray(
    const parser::AccObjectList &objectList) {
  for (const auto &accObject : objectList.v) {
    std::visit(
        common::visitors{
            [&](const parser::Designator &designator) {
              if (!IsLastNameArray(designator))
                context_.Say(designator.source,
                    "Only array element or subarray are allowed in %s directive"_err_en_US,
                    parser::ToUpperCaseLetters(
                        llvm::acc::getOpenACCDirectiveName(
                            GetContext().directive)
                            .str()));
            },
            [&](const auto &name) {
              context_.Say(name.source,
                  "Only array element or subarray are allowed in %s directive"_err_en_US,
                  parser::ToUpperCaseLetters(
                      llvm::acc::getOpenACCDirectiveName(GetContext().directive)
                          .str()));
            },
        },
        accObject.u);
  }
}

void AccAttributeVisitor::DoNotAllowAssumedSizedArray(
    const parser::AccObjectList &objectList) {
  for (const auto &accObject : objectList.v) {
    std::visit(
        common::visitors{
            [&](const parser::Designator &designator) {
              const auto &name{GetLastName(designator)};
              if (name.symbol && semantics::IsAssumedSizeArray(*name.symbol))
                context_.Say(designator.source,
                    "Assumed-size dummy arrays may not appear on the %s "
                    "directive"_err_en_US,
                    parser::ToUpperCaseLetters(
                        llvm::acc::getOpenACCDirectiveName(
                            GetContext().directive)
                            .str()));
            },
            [&](const auto &name) {

            },
        },
        accObject.u);
  }
}

bool AccAttributeVisitor::Pre(const parser::OpenACCCacheConstruct &x) {
  const auto &verbatim{std::get<parser::Verbatim>(x.t)};
  PushContext(verbatim.source, llvm::acc::Directive::ACCD_cache);
  ClearDataSharingAttributeObjects();

  const auto &objectListWithModifier =
      std::get<parser::AccObjectListWithModifier>(x.t);
  const auto &objectList =
      std::get<Fortran::parser::AccObjectList>(objectListWithModifier.t);

  // 2.10 Cache directive restriction: A var in a cache directive must be a
  // single array element or a simple subarray.
  AllowOnlyArrayAndSubArray(objectList);

  return true;
}

std::int64_t AccAttributeVisitor::GetAssociatedLoopLevelFromClauses(
    const parser::AccClauseList &x) {
  std::int64_t collapseLevel{0};
  for (const auto &clause : x.v) {
    if (const auto *collapseClause{
            std::get_if<parser::AccClause::Collapse>(&clause.u)}) {
      if (const auto v{EvaluateInt64(context_, collapseClause->v)}) {
        collapseLevel = *v;
      }
    }
  }

  if (collapseLevel) {
    return collapseLevel;
  }
  return 1; // default is outermost loop
}

void AccAttributeVisitor::PrivatizeAssociatedLoopIndex(
    const parser::OpenACCLoopConstruct &x) {
  std::int64_t level{GetContext().associatedLoopLevel};
  if (level <= 0) { // collpase value was negative or 0
    return;
  }
  Symbol::Flag ivDSA{Symbol::Flag::AccPrivate};

  const auto &outer{std::get<std::optional<parser::DoConstruct>>(x.t)};
  for (const parser::DoConstruct *loop{&*outer}; loop && level > 0; --level) {
    // go through all the nested do-loops and resolve index variables
    const parser::Name &iv{GetLoopIndex(*loop)};
    if (auto *symbol{ResolveAcc(iv, ivDSA, currScope())}) {
      symbol->set(Symbol::Flag::AccPreDetermined);
      iv.symbol = symbol; // adjust the symbol within region
      AddToContextObjectWithDSA(*symbol, ivDSA);
    }

    const auto &block{std::get<parser::Block>(loop->t)};
    const auto it{block.begin()};
    loop = it != block.end() ? GetDoConstructIf(*it) : nullptr;
  }
  CHECK(level == 0);
}

void AccAttributeVisitor::Post(const parser::AccDefaultClause &x) {
  if (!dirContext_.empty()) {
    switch (x.v) {
    case llvm::acc::DefaultValue::ACC_Default_present:
      SetContextDefaultDSA(Symbol::Flag::AccPresent);
      break;
    case llvm::acc::DefaultValue::ACC_Default_none:
      SetContextDefaultDSA(Symbol::Flag::AccNone);
      break;
    }
  }
}

// For OpenACC constructs, check all the data-refs within the constructs
// and adjust the symbol for each Name if necessary
void AccAttributeVisitor::Post(const parser::Name &name) {
  auto *symbol{name.symbol};
  if (symbol && !dirContext_.empty() && GetContext().withinConstruct) {
    if (!symbol->owner().IsDerivedType() && !symbol->has<ProcEntityDetails>() &&
        !IsObjectWithDSA(*symbol)) {
      if (Symbol * found{currScope().FindSymbol(name.source)}) {
        if (symbol != found) {
          name.symbol = found; // adjust the symbol within region
        } else if (GetContext().defaultDSA == Symbol::Flag::AccNone) {
          // 2.5.14.
          context_.Say(name.source,
              "The DEFAULT(NONE) clause requires that '%s' must be listed in "
              "a data-mapping clause"_err_en_US,
              symbol->name());
        }
      }
    }
  } // within OpenACC construct
}

Symbol *AccAttributeVisitor::ResolveAccCommonBlockName(
    const parser::Name *name) {
  if (!name) {
    return nullptr;
  } else if (auto *prev{
                 GetContext().scope.parent().FindCommonBlock(name->source)}) {
    name->symbol = prev;
    return prev;
  } else {
    return nullptr;
  }
}

void AccAttributeVisitor::ResolveAccObjectList(
    const parser::AccObjectList &accObjectList, Symbol::Flag accFlag) {
  for (const auto &accObject : accObjectList.v) {
    ResolveAccObject(accObject, accFlag);
  }
}

void AccAttributeVisitor::ResolveAccObject(
    const parser::AccObject &accObject, Symbol::Flag accFlag) {
  std::visit(
      common::visitors{
          [&](const parser::Designator &designator) {
            if (const auto *name{GetDesignatorNameIfDataRef(designator)}) {
              if (auto *symbol{ResolveAcc(*name, accFlag, currScope())}) {
                AddToContextObjectWithDSA(*symbol, accFlag);
                if (dataSharingAttributeFlags.test(accFlag)) {
                  CheckMultipleAppearances(*name, *symbol, accFlag);
                }
              }
            } else {
              // Array sections to be changed to substrings as needed
              if (AnalyzeExpr(context_, designator)) {
                if (std::holds_alternative<parser::Substring>(designator.u)) {
                  context_.Say(designator.source,
                      "Substrings are not allowed on OpenACC "
                      "directives or clauses"_err_en_US);
                }
              }
              // other checks, more TBD
            }
          },
          [&](const parser::Name &name) { // common block
            if (auto *symbol{ResolveAccCommonBlockName(&name)}) {
              CheckMultipleAppearances(
                  name, *symbol, Symbol::Flag::AccCommonBlock);
              for (auto &object : symbol->get<CommonBlockDetails>().objects()) {
                if (auto *resolvedObject{
                        ResolveAcc(*object, accFlag, currScope())}) {
                  AddToContextObjectWithDSA(*resolvedObject, accFlag);
                }
              }
            } else {
              context_.Say(name.source,
                  "COMMON block must be declared in the same scoping unit "
                  "in which the OpenACC directive or clause appears"_err_en_US);
            }
          },
      },
      accObject.u);
}

Symbol *AccAttributeVisitor::ResolveAcc(
    const parser::Name &name, Symbol::Flag accFlag, Scope &scope) {
  if (accFlagsRequireNewSymbol.test(accFlag)) {
    return DeclarePrivateAccessEntity(name, accFlag, scope);
  } else {
    return DeclareOrMarkOtherAccessEntity(name, accFlag);
  }
}

Symbol *AccAttributeVisitor::ResolveAcc(
    Symbol &symbol, Symbol::Flag accFlag, Scope &scope) {
  if (accFlagsRequireNewSymbol.test(accFlag)) {
    return DeclarePrivateAccessEntity(symbol, accFlag, scope);
  } else {
    return DeclareOrMarkOtherAccessEntity(symbol, accFlag);
  }
}

Symbol *AccAttributeVisitor::DeclareOrMarkOtherAccessEntity(
    const parser::Name &name, Symbol::Flag accFlag) {
  Symbol *prev{currScope().FindSymbol(name.source)};
  if (!name.symbol || !prev) {
    return nullptr;
  } else if (prev != name.symbol) {
    name.symbol = prev;
  }
  return DeclareOrMarkOtherAccessEntity(*prev, accFlag);
}

Symbol *AccAttributeVisitor::DeclareOrMarkOtherAccessEntity(
    Symbol &object, Symbol::Flag accFlag) {
  if (accFlagsRequireMark.test(accFlag)) {
    object.set(accFlag);
  }
  return &object;
}

static bool WithMultipleAppearancesAccException(
    const Symbol &symbol, Symbol::Flag flag) {
  return false; // Place holder
}

void AccAttributeVisitor::CheckMultipleAppearances(
    const parser::Name &name, const Symbol &symbol, Symbol::Flag accFlag) {
  const auto *target{&symbol};
  if (accFlagsRequireNewSymbol.test(accFlag)) {
    if (const auto *details{symbol.detailsIf<HostAssocDetails>()}) {
      target = &details->symbol();
    }
  }
  if (HasDataSharingAttributeObject(*target) &&
      !WithMultipleAppearancesAccException(symbol, accFlag)) {
    context_.Say(name.source,
        "'%s' appears in more than one data-sharing clause "
        "on the same OpenACC directive"_err_en_US,
        name.ToString());
  } else {
    AddDataSharingAttributeObject(*target);
  }
}

bool OmpAttributeVisitor::Pre(const parser::OpenMPBlockConstruct &x) {
  const auto &beginBlockDir{std::get<parser::OmpBeginBlockDirective>(x.t)};
  const auto &beginDir{std::get<parser::OmpBlockDirective>(beginBlockDir.t)};
  switch (beginDir.v) {
  case llvm::omp::Directive::OMPD_master:
  case llvm::omp::Directive::OMPD_ordered:
  case llvm::omp::Directive::OMPD_parallel:
  case llvm::omp::Directive::OMPD_single:
  case llvm::omp::Directive::OMPD_target:
  case llvm::omp::Directive::OMPD_target_data:
  case llvm::omp::Directive::OMPD_task:
  case llvm::omp::Directive::OMPD_teams:
  case llvm::omp::Directive::OMPD_workshare:
  case llvm::omp::Directive::OMPD_parallel_workshare:
  case llvm::omp::Directive::OMPD_target_teams:
  case llvm::omp::Directive::OMPD_target_parallel:
  case llvm::omp::Directive::OMPD_taskgroup:
    PushContext(beginDir.source, beginDir.v);
    break;
  default:
    // TODO others
    break;
  }
  ClearDataSharingAttributeObjects();
  ClearPrivateDataSharingAttributeObjects();
  ClearAllocateNames();
  return true;
}

void OmpAttributeVisitor::Post(const parser::OpenMPBlockConstruct &x) {
  const auto &beginBlockDir{std::get<parser::OmpBeginBlockDirective>(x.t)};
  const auto &beginDir{std::get<parser::OmpBlockDirective>(beginBlockDir.t)};
  switch (beginDir.v) {
  case llvm::omp::Directive::OMPD_parallel:
  case llvm::omp::Directive::OMPD_single:
  case llvm::omp::Directive::OMPD_target:
  case llvm::omp::Directive::OMPD_task:
  case llvm::omp::Directive::OMPD_teams:
  case llvm::omp::Directive::OMPD_parallel_workshare:
  case llvm::omp::Directive::OMPD_target_teams:
  case llvm::omp::Directive::OMPD_target_parallel: {
    bool hasPrivate;
    for (const auto *allocName : allocateNames_) {
      hasPrivate = false;
      for (auto privateObj : privateDataSharingAttributeObjects_) {
        const Symbol &symbolPrivate{*privateObj};
        if (allocName->source == symbolPrivate.name()) {
          hasPrivate = true;
          break;
        }
      }
      if (!hasPrivate) {
        context_.Say(allocName->source,
            "The ALLOCATE clause requires that '%s' must be listed in a "
            "private "
            "data-sharing attribute clause on the same directive"_err_en_US,
            allocName->ToString());
      }
    }
    break;
  }
  default:
    break;
  }
  PopContext();
}

bool OmpAttributeVisitor::Pre(const parser::OpenMPLoopConstruct &x) {
  const auto &beginLoopDir{std::get<parser::OmpBeginLoopDirective>(x.t)};
  const auto &beginDir{std::get<parser::OmpLoopDirective>(beginLoopDir.t)};
  const auto &clauseList{std::get<parser::OmpClauseList>(beginLoopDir.t)};
  switch (beginDir.v) {
  case llvm::omp::Directive::OMPD_distribute:
  case llvm::omp::Directive::OMPD_distribute_parallel_do:
  case llvm::omp::Directive::OMPD_distribute_parallel_do_simd:
  case llvm::omp::Directive::OMPD_distribute_simd:
  case llvm::omp::Directive::OMPD_do:
  case llvm::omp::Directive::OMPD_do_simd:
  case llvm::omp::Directive::OMPD_parallel_do:
  case llvm::omp::Directive::OMPD_parallel_do_simd:
  case llvm::omp::Directive::OMPD_simd:
  case llvm::omp::Directive::OMPD_target_parallel_do:
  case llvm::omp::Directive::OMPD_target_parallel_do_simd:
  case llvm::omp::Directive::OMPD_target_teams_distribute:
  case llvm::omp::Directive::OMPD_target_teams_distribute_parallel_do:
  case llvm::omp::Directive::OMPD_target_teams_distribute_parallel_do_simd:
  case llvm::omp::Directive::OMPD_target_teams_distribute_simd:
  case llvm::omp::Directive::OMPD_target_simd:
  case llvm::omp::Directive::OMPD_taskloop:
  case llvm::omp::Directive::OMPD_taskloop_simd:
  case llvm::omp::Directive::OMPD_teams_distribute:
  case llvm::omp::Directive::OMPD_teams_distribute_parallel_do:
  case llvm::omp::Directive::OMPD_teams_distribute_parallel_do_simd:
  case llvm::omp::Directive::OMPD_teams_distribute_simd:
    PushContext(beginDir.source, beginDir.v);
    break;
  default:
    break;
  }
  ClearDataSharingAttributeObjects();
  SetContextAssociatedLoopLevel(GetAssociatedLoopLevelFromClauses(clauseList));

  if (beginDir.v == llvm::omp::Directive::OMPD_do) {
    if (const auto &doConstruct{
            std::get<std::optional<parser::DoConstruct>>(x.t)}) {
      if (doConstruct.value().IsDoWhile()) {
        return true;
      }
    }
  }
  PrivatizeAssociatedLoopIndexAndCheckLoopLevel(x);
  ordCollapseLevel = GetAssociatedLoopLevelFromClauses(clauseList) + 1;
  return true;
}

void OmpAttributeVisitor::ResolveSeqLoopIndexInParallelOrTaskConstruct(
    const parser::Name &iv) {
  auto targetIt{dirContext_.rbegin()};
  for (;; ++targetIt) {
    if (targetIt == dirContext_.rend()) {
      return;
    }
    if (llvm::omp::parallelSet.test(targetIt->directive) ||
        llvm::omp::taskGeneratingSet.test(targetIt->directive)) {
      break;
    }
  }
  if (auto *symbol{ResolveOmp(iv, Symbol::Flag::OmpPrivate, targetIt->scope)}) {
    targetIt++;
    symbol->set(Symbol::Flag::OmpPreDetermined);
    iv.symbol = symbol; // adjust the symbol within region
    for (auto it{dirContext_.rbegin()}; it != targetIt; ++it) {
      AddToContextObjectWithDSA(*symbol, Symbol::Flag::OmpPrivate, *it);
    }
  }
}

// [OMP-4.5]2.15.1.1 Data-sharing Attribute Rules - Predetermined
//   - A loop iteration variable for a sequential loop in a parallel
//     or task generating construct is private in the innermost such
//     construct that encloses the loop
// Loop iteration variables are not well defined for DO WHILE loop.
// Use of DO CONCURRENT inside OpenMP construct is unspecified behavior
// till OpenMP-5.0 standard.
// In above both cases we skip the privatization of iteration variables.
bool OmpAttributeVisitor::Pre(const parser::DoConstruct &x) {
  // TODO:[OpenMP 5.1] DO CONCURRENT indices are private
  if (x.IsDoNormal()) {
    if (!dirContext_.empty() && GetContext().withinConstruct) {
      if (const auto &iv{GetLoopIndex(x)}; iv.symbol) {
        if (!iv.symbol->test(Symbol::Flag::OmpPreDetermined)) {
          ResolveSeqLoopIndexInParallelOrTaskConstruct(iv);
        } else {
          // TODO: conflict checks with explicitly determined DSA
        }
        ordCollapseLevel--;
        if (ordCollapseLevel) {
          if (const auto *details{iv.symbol->detailsIf<HostAssocDetails>()}) {
            const Symbol *tpSymbol = &details->symbol();
            if (tpSymbol->test(Symbol::Flag::OmpThreadprivate)) {
              context_.Say(iv.source,
                  "Loop iteration variable %s is not allowed in THREADPRIVATE."_err_en_US,
                  iv.ToString());
            }
          }
        }
      }
    }
  }
  return true;
}

std::int64_t OmpAttributeVisitor::GetAssociatedLoopLevelFromClauses(
    const parser::OmpClauseList &x) {
  std::int64_t orderedLevel{0};
  std::int64_t collapseLevel{0};

  const parser::OmpClause *ordClause{nullptr};
  const parser::OmpClause *collClause{nullptr};

  for (const auto &clause : x.v) {
    if (const auto *orderedClause{
            std::get_if<parser::OmpClause::Ordered>(&clause.u)}) {
      if (const auto v{EvaluateInt64(context_, orderedClause->v)}) {
        orderedLevel = *v;
      }
      ordClause = &clause;
    }
    if (const auto *collapseClause{
            std::get_if<parser::OmpClause::Collapse>(&clause.u)}) {
      if (const auto v{EvaluateInt64(context_, collapseClause->v)}) {
        collapseLevel = *v;
      }
      collClause = &clause;
    }
  }

  if (orderedLevel && (!collapseLevel || orderedLevel >= collapseLevel)) {
    SetAssociatedClause(*ordClause);
    return orderedLevel;
  } else if (!orderedLevel && collapseLevel) {
    SetAssociatedClause(*collClause);
    return collapseLevel;
  } // orderedLevel < collapseLevel is an error handled in structural checks
  return 1; // default is outermost loop
}

// 2.15.1.1 Data-sharing Attribute Rules - Predetermined
//   - The loop iteration variable(s) in the associated do-loop(s) of a do,
//     parallel do, taskloop, or distribute construct is (are) private.
//   - The loop iteration variable in the associated do-loop of a simd construct
//     with just one associated do-loop is linear with a linear-step that is the
//     increment of the associated do-loop.
//   - The loop iteration variables in the associated do-loops of a simd
//     construct with multiple associated do-loops are lastprivate.
void OmpAttributeVisitor::PrivatizeAssociatedLoopIndexAndCheckLoopLevel(
    const parser::OpenMPLoopConstruct &x) {
  std::int64_t level{GetContext().associatedLoopLevel};
  if (level <= 0) {
    return;
  }
  Symbol::Flag ivDSA;
  if (!llvm::omp::simdSet.test(GetContext().directive)) {
    ivDSA = Symbol::Flag::OmpPrivate;
  } else if (level == 1) {
    ivDSA = Symbol::Flag::OmpLinear;
  } else {
    ivDSA = Symbol::Flag::OmpLastPrivate;
  }

  const auto &outer{std::get<std::optional<parser::DoConstruct>>(x.t)};
  for (const parser::DoConstruct *loop{&*outer}; loop && level > 0; --level) {
    // go through all the nested do-loops and resolve index variables
    const parser::Name &iv{GetLoopIndex(*loop)};
    if (auto *symbol{ResolveOmp(iv, ivDSA, currScope())}) {
      symbol->set(Symbol::Flag::OmpPreDetermined);
      iv.symbol = symbol; // adjust the symbol within region
      AddToContextObjectWithDSA(*symbol, ivDSA);
    }

    const auto &block{std::get<parser::Block>(loop->t)};
    const auto it{block.begin()};
    loop = it != block.end() ? GetDoConstructIf(*it) : nullptr;
  }
  CheckAssocLoopLevel(level, GetAssociatedClause());
}
void OmpAttributeVisitor::CheckAssocLoopLevel(
    std::int64_t level, const parser::OmpClause *clause) {
  if (clause && level != 0) {
    context_.Say(clause->source,
        "The value of the parameter in the COLLAPSE or ORDERED clause must"
        " not be larger than the number of nested loops"
        " following the construct."_err_en_US);
  }
}

bool OmpAttributeVisitor::Pre(const parser::OpenMPSectionsConstruct &x) {
  const auto &beginSectionsDir{
      std::get<parser::OmpBeginSectionsDirective>(x.t)};
  const auto &beginDir{
      std::get<parser::OmpSectionsDirective>(beginSectionsDir.t)};
  switch (beginDir.v) {
  case llvm::omp::Directive::OMPD_parallel_sections:
  case llvm::omp::Directive::OMPD_sections:
    PushContext(beginDir.source, beginDir.v);
    break;
  default:
    break;
  }
  ClearDataSharingAttributeObjects();
  return true;
}

bool OmpAttributeVisitor::Pre(const parser::OpenMPCriticalConstruct &x) {
  const auto &criticalDir{std::get<parser::OmpCriticalDirective>(x.t)};
  PushContext(criticalDir.source, llvm::omp::Directive::OMPD_critical);
  return true;
}

bool OmpAttributeVisitor::Pre(const parser::OpenMPThreadprivate &x) {
  PushContext(x.source, llvm::omp::Directive::OMPD_threadprivate);
  const auto &list{std::get<parser::OmpObjectList>(x.t)};
  ResolveOmpObjectList(list, Symbol::Flag::OmpThreadprivate);
  return true;
}

void OmpAttributeVisitor::Post(const parser::OmpDefaultClause &x) {
  if (!dirContext_.empty()) {
    switch (x.v) {
    case parser::OmpDefaultClause::Type::Private:
      SetContextDefaultDSA(Symbol::Flag::OmpPrivate);
      break;
    case parser::OmpDefaultClause::Type::Firstprivate:
      SetContextDefaultDSA(Symbol::Flag::OmpFirstPrivate);
      break;
    case parser::OmpDefaultClause::Type::Shared:
      SetContextDefaultDSA(Symbol::Flag::OmpShared);
      break;
    case parser::OmpDefaultClause::Type::None:
      SetContextDefaultDSA(Symbol::Flag::OmpNone);
      break;
    }
  }
}

// For OpenMP constructs, check all the data-refs within the constructs
// and adjust the symbol for each Name if necessary
void OmpAttributeVisitor::Post(const parser::Name &name) {
  auto *symbol{name.symbol};
  if (symbol && !dirContext_.empty() && GetContext().withinConstruct) {
    if (!symbol->owner().IsDerivedType() && !symbol->has<ProcEntityDetails>() &&
        !IsObjectWithDSA(*symbol)) {
      // TODO: create a separate function to go through the rules for
      //       predetermined, explicitly determined, and implicitly
      //       determined data-sharing attributes (2.15.1.1).
      if (Symbol * found{currScope().FindSymbol(name.source)}) {
        if (symbol != found) {
          name.symbol = found; // adjust the symbol within region
        } else if (GetContext().defaultDSA == Symbol::Flag::OmpNone) {
          context_.Say(name.source,
              "The DEFAULT(NONE) clause requires that '%s' must be listed in "
              "a data-sharing attribute clause"_err_en_US,
              symbol->name());
        }
      }
    }
  } // within OpenMP construct
}

Symbol *OmpAttributeVisitor::ResolveName(const parser::Name *name) {
  if (auto *resolvedSymbol{
          name ? GetContext().scope.FindSymbol(name->source) : nullptr}) {
    name->symbol = resolvedSymbol;
    return resolvedSymbol;
  } else {
    return nullptr;
  }
}

void OmpAttributeVisitor::ResolveOmpName(
    const parser::Name &name, Symbol::Flag ompFlag) {
  if (ResolveName(&name)) {
    if (auto *resolvedSymbol{ResolveOmp(name, ompFlag, currScope())}) {
      if (dataSharingAttributeFlags.test(ompFlag)) {
        AddToContextObjectWithDSA(*resolvedSymbol, ompFlag);
      }
    }
  }
}

void OmpAttributeVisitor::ResolveOmpNameList(
    const std::list<parser::Name> &nameList, Symbol::Flag ompFlag) {
  for (const auto &name : nameList) {
    ResolveOmpName(name, ompFlag);
  }
}

Symbol *OmpAttributeVisitor::ResolveOmpCommonBlockName(
    const parser::Name *name) {
  if (auto *prev{name
              ? GetContext().scope.parent().FindCommonBlock(name->source)
              : nullptr}) {
    name->symbol = prev;
    return prev;
  }
  // Check if the Common Block is declared in the current scope
  if (auto *commonBlockSymbol{
          name ? GetContext().scope.FindCommonBlock(name->source) : nullptr}) {
    name->symbol = commonBlockSymbol;
    return commonBlockSymbol;
  }
  return nullptr;
}

void OmpAttributeVisitor::ResolveOmpObjectList(
    const parser::OmpObjectList &ompObjectList, Symbol::Flag ompFlag) {
  for (const auto &ompObject : ompObjectList.v) {
    ResolveOmpObject(ompObject, ompFlag);
  }
}

void OmpAttributeVisitor::ResolveOmpObject(
    const parser::OmpObject &ompObject, Symbol::Flag ompFlag) {
  std::visit(
      common::visitors{
          [&](const parser::Designator &designator) {
            if (const auto *name{GetDesignatorNameIfDataRef(designator)}) {
              if (auto *symbol{ResolveOmp(*name, ompFlag, currScope())}) {
                if (dataCopyingAttributeFlags.test(ompFlag)) {
                  CheckDataCopyingClause(*name, *symbol, ompFlag);
                } else {
                  AddToContextObjectWithDSA(*symbol, ompFlag);
                  if (dataSharingAttributeFlags.test(ompFlag)) {
                    CheckMultipleAppearances(*name, *symbol, ompFlag);
                  }
                  if (privateDataSharingAttributeFlags.test(ompFlag)) {
                    CheckPrivateDSAObject(*name, *symbol, ompFlag);
                  }

                  if (ompFlag == Symbol::Flag::OmpAllocate) {
                    AddAllocateName(name);
                  }
                }
              }
            } else {
              // Array sections to be changed to substrings as needed
              if (AnalyzeExpr(context_, designator)) {
                if (std::holds_alternative<parser::Substring>(designator.u)) {
                  context_.Say(designator.source,
                      "Substrings are not allowed on OpenMP "
                      "directives or clauses"_err_en_US);
                }
              }
              // other checks, more TBD
            }
          },
          [&](const parser::Name &name) { // common block
            if (auto *symbol{ResolveOmpCommonBlockName(&name)}) {
              if (!dataCopyingAttributeFlags.test(ompFlag)) {
                CheckMultipleAppearances(
                    name, *symbol, Symbol::Flag::OmpCommonBlock);
              }
              // 2.15.3 When a named common block appears in a list, it has the
              // same meaning as if every explicit member of the common block
              // appeared in the list
              for (auto &object : symbol->get<CommonBlockDetails>().objects()) {
                if (auto *resolvedObject{
                        ResolveOmp(*object, ompFlag, currScope())}) {
                  if (dataCopyingAttributeFlags.test(ompFlag)) {
                    CheckDataCopyingClause(name, *resolvedObject, ompFlag);
                  } else {
                    AddToContextObjectWithDSA(*resolvedObject, ompFlag);
                  }
                }
              }
            } else {
              context_.Say(name.source, // 2.15.3
                  "COMMON block must be declared in the same scoping unit "
                  "in which the OpenMP directive or clause appears"_err_en_US);
            }
          },
      },
      ompObject.u);
}

Symbol *OmpAttributeVisitor::ResolveOmp(
    const parser::Name &name, Symbol::Flag ompFlag, Scope &scope) {
  if (ompFlagsRequireNewSymbol.test(ompFlag)) {
    return DeclarePrivateAccessEntity(name, ompFlag, scope);
  } else {
    return DeclareOrMarkOtherAccessEntity(name, ompFlag);
  }
}

Symbol *OmpAttributeVisitor::ResolveOmp(
    Symbol &symbol, Symbol::Flag ompFlag, Scope &scope) {
  if (ompFlagsRequireNewSymbol.test(ompFlag)) {
    return DeclarePrivateAccessEntity(symbol, ompFlag, scope);
  } else {
    return DeclareOrMarkOtherAccessEntity(symbol, ompFlag);
  }
}

Symbol *OmpAttributeVisitor::DeclareOrMarkOtherAccessEntity(
    const parser::Name &name, Symbol::Flag ompFlag) {
  Symbol *prev{currScope().FindSymbol(name.source)};
  if (!name.symbol || !prev) {
    return nullptr;
  } else if (prev != name.symbol) {
    name.symbol = prev;
  }
  return DeclareOrMarkOtherAccessEntity(*prev, ompFlag);
}

Symbol *OmpAttributeVisitor::DeclareOrMarkOtherAccessEntity(
    Symbol &object, Symbol::Flag ompFlag) {
  if (ompFlagsRequireMark.test(ompFlag)) {
    object.set(ompFlag);
  }
  return &object;
}

static bool WithMultipleAppearancesOmpException(
    const Symbol &symbol, Symbol::Flag flag) {
  return (flag == Symbol::Flag::OmpFirstPrivate &&
             symbol.test(Symbol::Flag::OmpLastPrivate)) ||
      (flag == Symbol::Flag::OmpLastPrivate &&
          symbol.test(Symbol::Flag::OmpFirstPrivate));
}

void OmpAttributeVisitor::CheckMultipleAppearances(
    const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
  const auto *target{&symbol};
  if (ompFlagsRequireNewSymbol.test(ompFlag)) {
    if (const auto *details{symbol.detailsIf<HostAssocDetails>()}) {
      target = &details->symbol();
    }
  }
  if (HasDataSharingAttributeObject(*target) &&
      !WithMultipleAppearancesOmpException(symbol, ompFlag)) {
    context_.Say(name.source,
        "'%s' appears in more than one data-sharing clause "
        "on the same OpenMP directive"_err_en_US,
        name.ToString());
  } else {
    AddDataSharingAttributeObject(*target);
    if (privateDataSharingAttributeFlags.test(ompFlag)) {
      AddPrivateDataSharingAttributeObjects(*target);
    }
  }
}

void ResolveAccParts(
    SemanticsContext &context, const parser::ProgramUnit &node) {
  if (context.IsEnabled(common::LanguageFeature::OpenACC)) {
    AccAttributeVisitor{context}.Walk(node);
  }
}

void ResolveOmpParts(
    SemanticsContext &context, const parser::ProgramUnit &node) {
  if (context.IsEnabled(common::LanguageFeature::OpenMP)) {
    OmpAttributeVisitor{context}.Walk(node);
    if (!context.AnyFatalError()) {
      // The data-sharing attribute of the loop iteration variable for a
      // sequential loop (2.15.1.1) can only be determined when visiting
      // the corresponding DoConstruct, a second walk is to adjust the
      // symbols for all the data-refs of that loop iteration variable
      // prior to the DoConstruct.
      OmpAttributeVisitor{context}.Walk(node);
    }
  }
}

void OmpAttributeVisitor::CheckDataCopyingClause(
    const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
  const auto *checkSymbol{&symbol};
  if (const auto *details{symbol.detailsIf<HostAssocDetails>()})
    checkSymbol = &details->symbol();

  if (ompFlag == Symbol::Flag::OmpCopyIn) {
    // List of items/objects that can appear in a 'copyin' clause must be
    // 'threadprivate'
    if (!checkSymbol->test(Symbol::Flag::OmpThreadprivate))
      context_.Say(name.source,
          "Non-THREADPRIVATE object '%s' in COPYIN clause"_err_en_US,
          checkSymbol->name());
  } else if (ompFlag == Symbol::Flag::OmpCopyPrivate &&
      GetContext().directive == llvm::omp::Directive::OMPD_single) {
    // A list item that appears in a 'copyprivate' clause may not appear on a
    // 'private' or 'firstprivate' clause on a single construct
    if (IsObjectWithDSA(symbol) &&
        (symbol.test(Symbol::Flag::OmpPrivate) ||
            symbol.test(Symbol::Flag::OmpFirstPrivate))) {
      context_.Say(name.source,
          "COPYPRIVATE variable '%s' may not appear on a PRIVATE or "
          "FIRSTPRIVATE clause on a SINGLE construct"_err_en_US,
          symbol.name());
    } else {
      // List of items/objects that can appear in a 'copyprivate' clause must be
      // either 'private' or 'threadprivate' in enclosing context.
      if (!checkSymbol->test(Symbol::Flag::OmpThreadprivate) &&
          !(HasSymbolInEnclosingScope(symbol, currScope()) &&
              symbol.test(Symbol::Flag::OmpPrivate))) {
        context_.Say(name.source,
            "COPYPRIVATE variable '%s' is not PRIVATE or THREADPRIVATE in "
            "outer context"_err_en_US,
            symbol.name());
      }
    }
  }
}

void OmpAttributeVisitor::CheckPrivateDSAObject(
    const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
  const auto &ultimateSymbol{symbol.GetUltimate()};
  llvm::StringRef clauseName{"PRIVATE"};
  if (ompFlag == Symbol::Flag::OmpFirstPrivate)
    clauseName = "FIRSTPRIVATE";
  else if (ompFlag == Symbol::Flag::OmpLastPrivate)
    clauseName = "LASTPRIVATE";

  if (ultimateSymbol.test(Symbol::Flag::InNamelist)) {
    context_.Say(name.source,
        "Variable '%s' in NAMELIST cannot be in a %s clause"_err_en_US,
        name.ToString(), clauseName.str());
  }

  if (stmtFunctionExprSymbols_.find(ultimateSymbol) !=
      stmtFunctionExprSymbols_.end()) {
    context_.Say(name.source,
        "Variable '%s' in STATEMENT FUNCTION expression cannot be in a "
        "%s clause"_err_en_US,
        name.ToString(), clauseName.str());
  }
}

void OmpAttributeVisitor::CheckSourceLabel(const parser::Label &label) {
  // Get the context to check if the statement causing a jump to the 'label' is
  // in an enclosing OpenMP construct
  std::optional<DirContext> thisContext{GetContextIf()};
  sourceLabels_.emplace(
      label, std::make_pair(currentStatementSource_, thisContext));
  // Check if the statement with 'label' to which a jump is being introduced
  // has already been encountered
  auto it{targetLabels_.find(label)};
  if (it != targetLabels_.end()) {
    // Check if both the statement with 'label' and the statement that causes a
    // jump to the 'label' are in the same scope
    CheckLabelContext(currentStatementSource_, it->second.first, thisContext,
        it->second.second);
  }
}

// Check for invalid branch into or out of OpenMP structured blocks
void OmpAttributeVisitor::CheckLabelContext(const parser::CharBlock source,
    const parser::CharBlock target, std::optional<DirContext> sourceContext,
    std::optional<DirContext> targetContext) {
  if (targetContext &&
      (!sourceContext ||
          (sourceContext->scope != targetContext->scope &&
              !DoesScopeContain(
                  &targetContext->scope, sourceContext->scope)))) {
    context_
        .Say(source, "invalid branch into an OpenMP structured block"_err_en_US)
        .Attach(target, "In the enclosing %s directive branched into"_en_US,
            parser::ToUpperCaseLetters(
                llvm::omp::getOpenMPDirectiveName(targetContext->directive)
                    .str()));
  }
  if (sourceContext &&
      (!targetContext ||
          (sourceContext->scope != targetContext->scope &&
              !DoesScopeContain(
                  &sourceContext->scope, targetContext->scope)))) {
    context_
        .Say(source,
            "invalid branch leaving an OpenMP structured block"_err_en_US)
        .Attach(target, "Outside the enclosing %s directive"_en_US,
            parser::ToUpperCaseLetters(
                llvm::omp::getOpenMPDirectiveName(sourceContext->directive)
                    .str()));
  }
}

bool OmpAttributeVisitor::HasSymbolInEnclosingScope(
    const Symbol &symbol, Scope &scope) {
  const auto symbols{scope.parent().GetSymbols()};
  auto it{std::find(symbols.begin(), symbols.end(), symbol)};
  return it != symbols.end();
}

} // namespace Fortran::semantics