llvm-project

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//===-- runtime/misc-intrinsic.cpp ----------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "flang/Runtime/misc-intrinsic.h"
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#include "terminator.h"
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#include "tools.h"
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#include "flang/Common/optional.h"
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#include "flang/Runtime/descriptor.h"
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#include <algorithm>
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#include <cstring>
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namespace Fortran::runtime {
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static RT_API_ATTRS void TransferImpl(Descriptor &result,
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    const Descriptor &source, const Descriptor &mold, const char *sourceFile,
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    int line, Fortran::common::optional<std::int64_t> resultExtent) {
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  int rank{resultExtent.has_value() ? 1 : 0};
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  std::size_t elementBytes{mold.ElementBytes()};
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  result.Establish(mold.type(), elementBytes, nullptr, rank, nullptr,
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      CFI_attribute_allocatable, mold.Addendum() != nullptr);
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  if (resultExtent) {
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    result.GetDimension(0).SetBounds(1, *resultExtent);
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  }
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  if (const DescriptorAddendum * addendum{mold.Addendum()}) {
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    *result.Addendum() = *addendum;
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  }
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  if (int stat{result.Allocate()}) {
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    Terminator{sourceFile, line}.Crash(
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        "TRANSFER: could not allocate memory for result; STAT=%d", stat);
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  }
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  char *to{result.OffsetElement<char>()};
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  std::size_t resultBytes{result.Elements() * result.ElementBytes()};
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  const std::size_t sourceElementBytes{source.ElementBytes()};
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  std::size_t sourceElements{source.Elements()};
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  SubscriptValue sourceAt[maxRank];
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  source.GetLowerBounds(sourceAt);
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  while (resultBytes > 0 && sourceElements > 0) {
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    std::size_t toMove{std::min(resultBytes, sourceElementBytes)};
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    std::memcpy(to, source.Element<char>(sourceAt), toMove);
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    to += toMove;
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    resultBytes -= toMove;
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    --sourceElements;
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    source.IncrementSubscripts(sourceAt);
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  }
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  if (resultBytes > 0) {
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    std::memset(to, 0, resultBytes);
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  }
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}
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extern "C" {
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RT_EXT_API_GROUP_BEGIN
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void RTDEF(Transfer)(Descriptor &result, const Descriptor &source,
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    const Descriptor &mold, const char *sourceFile, int line) {
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  Fortran::common::optional<std::int64_t> elements;
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  if (mold.rank() > 0) {
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    if (std::size_t sourceElementBytes{
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            source.Elements() * source.ElementBytes()}) {
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      if (std::size_t moldElementBytes{mold.ElementBytes()}) {
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        elements = static_cast<std::int64_t>(
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            (sourceElementBytes + moldElementBytes - 1) / moldElementBytes);
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      } else {
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        Terminator{sourceFile, line}.Crash("TRANSFER: zero-sized type of MOLD= "
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                                           "when SOURCE= is not zero-sized");
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      }
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    } else {
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      elements = std::int64_t{0};
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    }
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  }
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  return TransferImpl(
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      result, source, mold, sourceFile, line, std::move(elements));
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}
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void RTDEF(TransferSize)(Descriptor &result, const Descriptor &source,
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    const Descriptor &mold, const char *sourceFile, int line,
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    std::int64_t size) {
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  return TransferImpl(result, source, mold, sourceFile, line, size);
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}
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RT_EXT_API_GROUP_END
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} // extern "C"
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} // namespace Fortran::runtime
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