flang/lib/Lower/OpenMP/Utils.cpp

//===-- Utils..cpp ----------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
//
//===----------------------------------------------------------------------===//

#include "Utils.h"
#include "Clauses.h"

#include <flang/Lower/AbstractConverter.h>
#include <flang/Lower/ConvertType.h>
#include <flang/Optimizer/Builder/FIRBuilder.h>
#include <flang/Parser/parse-tree.h>
#include <flang/Parser/tools.h>
#include <flang/Semantics/tools.h>
#include <llvm/Support/CommandLine.h>

llvm::cl::opt<bool> treatIndexAsSection(
    "openmp-treat-index-as-section",
    llvm::cl::desc("In the OpenMP data clauses treat `a(N)` as `a(N:N)`."),
    llvm::cl::init(true));

llvm::cl::opt<bool> enableDelayedPrivatization(
    "openmp-enable-delayed-privatization",
    llvm::cl::desc(
        "Emit `[first]private` variables as clauses on the MLIR ops."),
    llvm::cl::init(false));

namespace Fortran {
namespace lower {
namespace omp {

int64_t getCollapseValue(const List<Clause> &clauses) {
  auto iter = llvm::find_if(clauses, [](const Clause &clause) {
    return clause.id == llvm::omp::Clause::OMPC_collapse;
  });
  if (iter != clauses.end()) {
    const auto &collapse = std::get<clause::Collapse>(iter->u);
    return evaluate::ToInt64(collapse.v).value();
  }
  return 1;
}

void genObjectList(const ObjectList &objects,
                   Fortran::lower::AbstractConverter &converter,
                   llvm::SmallVectorImpl<mlir::Value> &operands) {
  for (const Object &object : objects) {
    const Fortran::semantics::Symbol *sym = object.id();
    assert(sym && "Expected Symbol");
    if (mlir::Value variable = converter.getSymbolAddress(*sym)) {
      operands.push_back(variable);
    } else if (const auto *details =
                   sym->detailsIf<Fortran::semantics::HostAssocDetails>()) {
      operands.push_back(converter.getSymbolAddress(details->symbol()));
      converter.copySymbolBinding(details->symbol(), *sym);
    }
  }
}

mlir::Type getLoopVarType(Fortran::lower::AbstractConverter &converter,
                          std::size_t loopVarTypeSize) {
  // OpenMP runtime requires 32-bit or 64-bit loop variables.
  loopVarTypeSize = loopVarTypeSize * 8;
  if (loopVarTypeSize < 32) {
    loopVarTypeSize = 32;
  } else if (loopVarTypeSize > 64) {
    loopVarTypeSize = 64;
    mlir::emitWarning(converter.getCurrentLocation(),
                      "OpenMP loop iteration variable cannot have more than 64 "
                      "bits size and will be narrowed into 64 bits.");
  }
  assert((loopVarTypeSize == 32 || loopVarTypeSize == 64) &&
         "OpenMP loop iteration variable size must be transformed into 32-bit "
         "or 64-bit");
  return converter.getFirOpBuilder().getIntegerType(loopVarTypeSize);
}

void gatherFuncAndVarSyms(
    const ObjectList &objects, mlir::omp::DeclareTargetCaptureClause clause,
    llvm::SmallVectorImpl<DeclareTargetCapturePair> &symbolAndClause) {
  for (const Object &object : objects)
    symbolAndClause.emplace_back(clause, *object.id());
}

Fortran::semantics::Symbol *
getOmpObjectSymbol(const Fortran::parser::OmpObject &ompObject) {
  Fortran::semantics::Symbol *sym = nullptr;
  std::visit(
      Fortran::common::visitors{
          [&](const Fortran::parser::Designator &designator) {
            if (auto *arrayEle =
                    Fortran::parser::Unwrap<Fortran::parser::ArrayElement>(
                        designator)) {
              sym = GetFirstName(arrayEle->base).symbol;
            } else if (auto *structComp = Fortran::parser::Unwrap<
                           Fortran::parser::StructureComponent>(designator)) {
              sym = structComp->component.symbol;
            } else if (const Fortran::parser::Name *name =
                           Fortran::semantics::getDesignatorNameIfDataRef(
                               designator)) {
              sym = name->symbol;
            }
          },
          [&](const Fortran::parser::Name &name) { sym = name.symbol; }},
      ompObject.u);
  return sym;
}

} // namespace omp
} // namespace lower
} // namespace Fortran