//===--- Level Zero Target RTL Implementation -----------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Level Zero Program abstraction.
//
//===----------------------------------------------------------------------===//

#include <fstream>
#ifdef _WIN32
#include <fcntl.h>
#include <io.h>
#else
#include <dlfcn.h>
#include <sys/stat.h>
#include <unistd.h>
#endif // !_WIN32

#include "L0Plugin.h"
#include "L0Program.h"

namespace llvm::omp::target::plugin {

Error L0GlobalHandlerTy::getGlobalMetadataFromDevice(GenericDeviceTy &Device,
                                                     DeviceImageTy &Image,
                                                     GlobalTy &DeviceGlobal) {
  const char *GlobalName = DeviceGlobal.getName().data();

  L0ProgramTy &Program = L0ProgramTy::makeL0Program(Image);
  auto AddrOrErr = Program.getSymbolDeviceAddr(GlobalName);
  if (!AddrOrErr)
    return AddrOrErr.takeError();

  // Save the pointer to the symbol allowing nullptr.
  DeviceGlobal.setPtr(*AddrOrErr);

  return Plugin::success();
}

inline L0DeviceTy &L0ProgramTy::getL0Device() const {
  return L0DeviceTy::makeL0Device(getDevice());
}

Error L0ProgramTy::deinit() {
  for (auto *Kernel : Kernels) {
    if (auto Err = Kernel->deinit())
      return Err;
    getL0Device().getPlugin().free(Kernel);
  }
  for (auto Module : Modules) {
    CALL_ZE_RET_ERROR(zeModuleDestroy, Module);
  }
  return Plugin::success();
}

Error L0ProgramBuilderTy::addModule(size_t Size, const uint8_t *Image,
                                    const std::string_view CommonBuildOptions,
                                    ze_module_format_t Format) {
  const ze_module_constants_t SpecConstants =
      LevelZeroPluginTy::getOptions().CommonSpecConstants.getModuleConstants();
  auto &l0Device = getL0Device();
  std::string BuildOptions(CommonBuildOptions);

  bool IsLibModule =
      BuildOptions.find("-library-compilation") != std::string::npos;

  ze_module_desc_t ModuleDesc{};
  ModuleDesc.stype = ZE_STRUCTURE_TYPE_MODULE_DESC;
  ModuleDesc.pNext = nullptr;
  ModuleDesc.format = Format;
  ze_module_handle_t Module = nullptr;
  ze_module_build_log_handle_t BuildLog = nullptr;

  // Build a single module from a single image.
  ModuleDesc.inputSize = Size;
  ModuleDesc.pInputModule = Image;
  ModuleDesc.pBuildFlags = BuildOptions.c_str();
  ModuleDesc.pConstants = &SpecConstants;
  CALL_ZE_RET_ERROR(zeModuleCreate, l0Device.getZeContext(),
                    l0Device.getZeDevice(), &ModuleDesc, &Module, &BuildLog);

  // Check if module link is required. We do not need this check for
  // library module.
  if (!RequiresModuleLink && !IsLibModule) {
    ze_module_properties_t Properties = {ZE_STRUCTURE_TYPE_MODULE_PROPERTIES,
                                         nullptr, 0};
    CALL_ZE_RET_ERROR(zeModuleGetProperties, Module, &Properties);
    RequiresModuleLink = Properties.flags & ZE_MODULE_PROPERTY_FLAG_IMPORTS;
  }
  // For now, assume the first module contains libraries, globals.
  if (Modules.empty())
    GlobalModule = Module;
  Modules.push_back(Module);
  l0Device.addGlobalModule(Module);
  return Plugin::success();
}

Error L0ProgramBuilderTy::linkModules() {
  auto &l0Device = getL0Device();
  if (!RequiresModuleLink) {
    ODBG(OLDT_Module) << "Module link is not required";
    return Plugin::success();
  }

  if (Modules.empty())
    return Plugin::error(ErrorCode::UNKNOWN,
                         "Invalid number of modules when linking modules");

  ze_module_build_log_handle_t LinkLog = nullptr;
  CALL_ZE_RET_ERROR(zeModuleDynamicLink,
                    static_cast<uint32_t>(l0Device.getNumGlobalModules()),
                    l0Device.getGlobalModulesArray(), &LinkLog);
  return Plugin::success();
}

static void replaceDriverOptsWithBackendOpts(const L0DeviceTy &Device,
                                             std::string &Options) {
  // Options that need to be replaced with backend-specific options
  static const struct {
    std::string Option;
    std::string BackendOption;
  } OptionTranslationTable[] = {
      {"-ftarget-compile-fast",
       "-igc_opts 'PartitionUnit=1,SubroutineThreshold=50000'"},
      {"-foffload-fp32-prec-div", "-ze-fp32-correctly-rounded-divide-sqrt"},
      {"-foffload-fp32-prec-sqrt", "-ze-fp32-correctly-rounded-divide-sqrt"},
  };

  for (const auto &OptPair : OptionTranslationTable) {
    const size_t Pos = Options.find(OptPair.Option);
    if (Pos != std::string::npos)
      Options.replace(Pos, OptPair.Option.length(), OptPair.BackendOption);
  }
}

// FIXME: move this to llvm/BinaryFormat/ELF.h and elf.h:
#define NT_INTEL_ONEOMP_OFFLOAD_VERSION 1
#define NT_INTEL_ONEOMP_OFFLOAD_IMAGE_COUNT 2
#define NT_INTEL_ONEOMP_OFFLOAD_IMAGE_AUX 3

bool isValidOneOmpImage(StringRef Image, uint64_t &MajorVer,
                        uint64_t &MinorVer) {
  const auto MB = MemoryBuffer::getMemBuffer(Image,
                                             /*BufferName=*/"",
                                             /*RequiresNullTerminator=*/false);
  auto ExpectedNewE =
      ELFObjectFileBase::createELFObjectFile(MB->getMemBufferRef());
  if (!ExpectedNewE) {
    ODBG(OLDT_Module) << "Warning: unable to get ELF handle!";
    return false;
  }
  bool Res = false;
  auto processObjF = [&](const auto ELFObjF) {
    if (!ELFObjF) {
      ODBG(OLDT_Module) << "Warning: Unexpected ELF type!";
      return false;
    }
    const auto &ELFF = ELFObjF->getELFFile();
    auto Sections = ELFF.sections();
    if (!Sections) {
      ODBG(OLDT_Module) << "Warning: unable to get ELF sections!";
      return false;
    }
    bool SeenOffloadSection = false;
    for (auto Sec : *Sections) {
      if (Sec.sh_type != ELF::SHT_NOTE)
        continue;
      Error Err = Plugin::success();
      for (auto Note : ELFF.notes(Sec, Err)) {
        if (Err) {
          ODBG(OLDT_Module) << "Warning: unable to get ELF notes handle!";
          return false;
        }
        if (Note.getName() != "INTELONEOMPOFFLOAD")
          continue;
        SeenOffloadSection = true;
        if (Note.getType() != NT_INTEL_ONEOMP_OFFLOAD_VERSION)
          continue;

        std::string DescStr(std::move(Note.getDescAsStringRef(4).str()));
        const auto DelimPos = DescStr.find('.');
        if (DelimPos == std::string::npos) {
          // The version has to look like "Major#.Minor#".
          ODBG(OLDT_Module)
              << "Invalid NT_INTEL_ONEOMP_OFFLOAD_VERSION: '" << DescStr << "'";
          return false;
        }
        const std::string MajorVerStr = DescStr.substr(0, DelimPos);
        DescStr.erase(0, DelimPos + 1);
        MajorVer = std::stoull(MajorVerStr);
        MinorVer = std::stoull(DescStr);
        return (MajorVer == 1 && MinorVer == 0);
      }
    }
    return SeenOffloadSection;
  };
  if (const auto *O = dyn_cast<ELF64LEObjectFile>((*ExpectedNewE).get())) {
    Res = processObjF(O);
  } else if (const auto *O =
                 dyn_cast<ELF32LEObjectFile>((*ExpectedNewE).get())) {
    Res = processObjF(O);
  } else {
    assert(false && "Unexpected ELF format");
  }
  return Res;
}

Error L0ProgramBuilderTy::buildModules(const std::string_view BuildOptions) {
  auto &l0Device = getL0Device();
  auto Image = getMemoryBuffer();
  if (identify_magic(Image.getBuffer()) == file_magic::spirv_object) {
    // Handle legacy plain SPIR-V image.
    const uint8_t *ImgBegin =
        reinterpret_cast<const uint8_t *>(Image.getBufferStart());
    return addModule(Image.getBufferSize(), ImgBegin, BuildOptions,
                     ZE_MODULE_FORMAT_IL_SPIRV);
  }

  uint64_t MajorVer, MinorVer;
  if (!isValidOneOmpImage(Image.getBuffer(), MajorVer, MinorVer)) {
    ODBG(OLDT_Module) << "Warning: image is not a valid oneAPI OpenMP image.";
    return Plugin::error(ErrorCode::UNKNOWN, "Invalid oneAPI OpenMP image");
  }

  // Iterate over the images and pick the first one that fits.
  uint64_t ImageCount = 0;
  struct V1ImageInfo {
    // 0 - native, 1 - SPIR-V.
    uint64_t Format = std::numeric_limits<uint64_t>::max();
    std::string CompileOpts;
    std::string LinkOpts;
    // We may have multiple sections created from split-kernel mode.
    std::vector<const uint8_t *> PartBegin;
    std::vector<uint64_t> PartSize;

    V1ImageInfo(uint64_t Format, std::string CompileOpts, std::string LinkOpts)
        : Format(Format), CompileOpts(std::move(CompileOpts)),
          LinkOpts(std::move(LinkOpts)) {}
  };
  std::unordered_map<uint64_t, V1ImageInfo> AuxInfo;

  auto ExpectedNewE = ELFObjectFileBase::createELFObjectFile(Image);
  assert(ExpectedNewE &&
         "isValidOneOmpImage() returns true for invalid ELF image");
  auto processELF = [&](auto *EObj) {
    assert(EObj && "isValidOneOmpImage() returns true for invalid ELF image.");
    const auto &E = EObj->getELFFile();
    // Collect auxiliary information.
    uint64_t MaxImageIdx = 0;

    auto Sections = E.sections();
    assert(Sections && "isValidOneOmpImage() returns true for ELF image with "
                       "invalid sections.");

    for (auto Sec : *Sections) {
      if (Sec.sh_type != ELF::SHT_NOTE)
        continue;
      Error Err = Plugin::success();
      for (auto Note : E.notes(Sec, Err)) {
        assert(!Err && "isValidOneOmpImage() returns true for ELF image with "
                       "invalid notes.");
        if (Note.getName().str() != "INTELONEOMPOFFLOAD")
          continue;

        const uint64_t Type = Note.getType();
        auto DescStrRef = Note.getDescAsStringRef(4);
        switch (Type) {
        default:
          ODBG(OLDT_Module) << "Warning: unrecognized INTELONEOMPOFFLOAD note.";
          break;
        case NT_INTEL_ONEOMP_OFFLOAD_VERSION:
          break;
        case NT_INTEL_ONEOMP_OFFLOAD_IMAGE_COUNT:
          if (DescStrRef.getAsInteger(10, ImageCount)) {
            ODBG(OLDT_Module) << "Warning: invalid "
                              << "NT_INTEL_ONEOMP_OFFLOAD_IMAGE_COUNT: '"
                              << DescStrRef.str() << "'";
            ImageCount = 0;
          }
          break;
        case NT_INTEL_ONEOMP_OFFLOAD_IMAGE_AUX:
          llvm::SmallVector<llvm::StringRef, 4> Parts;
          DescStrRef.split(Parts, '\0', /* MaxSplit = */ 4,
                           /* KeepEmpty = */ true);

          // Ignore records with less than 4 strings.
          if (Parts.size() != 4) {
            ODBG(OLDT_Module) << "Warning: short "
                              << "NT_INTEL_ONEOMP_OFFLOAD_IMAGE_AUX "
                              << "record is ignored.";
            continue;
          }

          uint64_t Idx = 0;
          if (Parts[0].getAsInteger(10, Idx)) {
            ODBG(OLDT_Module) << "Warning: ignoring auxiliary information "
                              << "(invalid index '" << Parts[0].str() << "').";
            continue;
          }
          MaxImageIdx = (std::max)(MaxImageIdx, Idx);
          if (AuxInfo.find(Idx) != AuxInfo.end()) {
            ODBG(OLDT_Module) << "Warning: duplicate auxiliary information for "
                              << "image " << Idx << " is ignored.";
            continue;
          }

          uint64_t Part1Id;
          if (Parts[1].getAsInteger(10, Part1Id)) {
            ODBG(OLDT_Module)
                << "Warning: ignoring auxiliary information "
                << "(invalid part id '" << Parts[1].str() << "').";
            continue;
          }

          AuxInfo.emplace(
              std::piecewise_construct, std::forward_as_tuple(Idx),
              std::forward_as_tuple(Part1Id, Parts[2].str(), Parts[3].str()));
          // Image pointer and size will be initialized later.
        }
      }
    }

    if (MaxImageIdx >= ImageCount)
      ODBG(OLDT_Module) << "Warning: invalid image index found in auxiliary "
                        << "information.";

    for (auto Sec : *Sections) {
      const char *Prefix = "__openmp_offload_spirv_";
      auto ExpectedSectionName = E.getSectionName(Sec);
      assert(ExpectedSectionName && "isValidOneOmpImage() returns true for ELF "
                                    "image with invalid section names");
      auto &SectionNameRef = *ExpectedSectionName;
      if (!SectionNameRef.consume_front(Prefix))
        continue;

      // Expected section name in split-kernel mode with the following pattern:
      // __openmp_offload_spirv_<image_id>_<part_id>
      auto Parts = SectionNameRef.split('_');
      // It seems that we do not need part ID as long as they are ordered
      // in the image and we keep the ordering in the runtime.
      SectionNameRef = Parts.first;
      if (Parts.second.empty()) {
        ODBG(OLDT_Module) << "Found a single section in the image";
      } else {
        ODBG(OLDT_Module) << "Found a split section in the image";
      }

      uint64_t Idx = 0;
      if (SectionNameRef.getAsInteger(10, Idx)) {
        ODBG(OLDT_Module) << "Warning: ignoring image section (invalid index '"
                          << SectionNameRef.str() << "').";
        continue;
      }
      if (Idx >= ImageCount) {
        ODBG(OLDT_Module) << "Warning: ignoring image section (index " << Idx
                          << " is out of range).";
        continue;
      }

      auto AuxInfoIt = AuxInfo.find(Idx);
      if (AuxInfoIt == AuxInfo.end()) {
        ODBG(OLDT_Module) << "Warning: ignoring image section (no aux info).";
        continue;
      }
      auto Contents = E.getSectionContents(Sec);
      assert(Contents);
      AuxInfoIt->second.PartBegin.push_back((*Contents).data());
      AuxInfoIt->second.PartSize.push_back(Sec.sh_size);
    }
  };

  if (auto *O = dyn_cast<ELF64LEObjectFile>((*ExpectedNewE).get())) {
    processELF(O);
  } else if (auto *O = dyn_cast<ELF32LEObjectFile>((*ExpectedNewE).get())) {
    processELF(O);
  } else {
    assert(false && "Unexpected ELF format");
  }

  for (uint64_t Idx = 0; Idx < ImageCount; ++Idx) {
    const auto It = AuxInfo.find(Idx);
    if (It == AuxInfo.end()) {
      ODBG(OLDT_Module) << "Warning: image " << Idx
                        << " without auxiliary information is ingored.";
      continue;
    }

    const auto NumParts = It->second.PartBegin.size();
    // Split-kernel is not supported in SPIRV format.
    if (NumParts > 1 && It->second.Format != 0) {
      ODBG(OLDT_Module) << "Warning: split-kernel images are not supported in "
                        << "SPIRV format";
      continue;
    }

    // Skip unknown image format.
    if (It->second.Format != 0 && It->second.Format != 1) {
      ODBG(OLDT_Module) << "Warning: image " << Idx << " is ignored due to "
                        << "unknown format.";
      continue;
    }

    const bool IsBinary = (It->second.Format == 0);
    const auto ModuleFormat =
        IsBinary ? ZE_MODULE_FORMAT_NATIVE : ZE_MODULE_FORMAT_IL_SPIRV;
    std::string Options(BuildOptions);
    {
      Options += " " + It->second.CompileOpts + " " + It->second.LinkOpts;
      replaceDriverOptsWithBackendOpts(l0Device, Options);
    }

    for (size_t I = 0; I < NumParts; I++) {
      const unsigned char *ImgBegin =
          reinterpret_cast<const unsigned char *>(It->second.PartBegin[I]);
      size_t ImgSize = It->second.PartSize[I];

      ODBG(OLDT_Module) << "Creating module from "
                        << (IsBinary ? "Binary" : "SPIR-V") << " image part #"
                        << Idx << "-" << I << ".";
      if (auto Err = addModule(ImgSize, ImgBegin, Options, ModuleFormat))
        return Err;
    }
    ODBG(OLDT_Module) << "Created module from image #" << Idx << ".";

    if (RequiresModuleLink) {
      ODBG(OLDT_Module) << "Linking modules after adding image #" << Idx << ".";
      if (auto Err = linkModules())
        return Err;
    }

    return Plugin::success();
  }

  return Plugin::error(ErrorCode::UNKNOWN, "Failed to create program modules.");
}

Expected<std::unique_ptr<MemoryBuffer>> L0ProgramBuilderTy::getELF() {
  assert(GlobalModule != nullptr && "GlobalModule is null");

  size_t Size = 0;

  CALL_ZE_RET_ERROR(zeModuleGetNativeBinary, GlobalModule, &Size, nullptr);
  std::vector<uint8_t> ELFData(Size);
  CALL_ZE_RET_ERROR(zeModuleGetNativeBinary, GlobalModule, &Size,
                    ELFData.data());
  return MemoryBuffer::getMemBufferCopy(
      StringRef(reinterpret_cast<const char *>(ELFData.data()), Size),
      /*BufferName=*/"L0Program ELF");
}

Expected<void *> L0ProgramTy::getSymbolDeviceAddr(const char *CName) const {
  ODBG(OLDT_Module) << "Looking up OpenMP global variable '" << CName << "'.";

  if (!GlobalModule || !CName)
    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
                         "Invalid arguments to getSymbolDeviceAddr");

  size_t SizeDummy = 0;
  void *DevicePtr = nullptr;
  ze_result_t RC;
  for (auto Module : Modules) {
    CALL_ZE(RC, zeModuleGetGlobalPointer, Module, CName, &SizeDummy,
            &DevicePtr);
    if (RC == ZE_RESULT_SUCCESS && DevicePtr)
      return DevicePtr;
    CALL_ZE(RC, zeModuleGetFunctionPointer, Module, CName, &DevicePtr);
    if (RC == ZE_RESULT_SUCCESS && DevicePtr)
      return DevicePtr;
  }
  return Plugin::error(ErrorCode::INVALID_ARGUMENT,
                       "Symbol '%s' not found on device", CName);
}

Error L0ProgramTy::readGlobalVariable(const char *Name, size_t Size,
                                      void *HostPtr) {
  size_t SizeDummy = 0;
  void *DevicePtr = nullptr;
  ze_result_t RC;
  CALL_ZE(RC, zeModuleGetGlobalPointer, GlobalModule, Name, &SizeDummy,
          &DevicePtr);
  if (RC != ZE_RESULT_SUCCESS || !DevicePtr) {
    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
                         "Cannot read from device global variable %s", Name);
  }
  return getL0Device().enqueueMemCopy(HostPtr, DevicePtr, Size);
}

Error L0ProgramTy::writeGlobalVariable(const char *Name, size_t Size,
                                       const void *HostPtr) {
  size_t SizeDummy = 0;
  void *DevicePtr = nullptr;
  ze_result_t RC;
  CALL_ZE(RC, zeModuleGetGlobalPointer, GlobalModule, Name, &SizeDummy,
          &DevicePtr);
  if (RC != ZE_RESULT_SUCCESS || !DevicePtr) {
    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
                         "Cannot write to device global variable %s", Name);
  }
  return getL0Device().enqueueMemCopy(DevicePtr, HostPtr, Size);
}

Error L0ProgramTy::loadModuleKernels() {
  // We need to build kernels here before filling the offload entries since we
  // don't know which module contains a specific kernel with a name.
  for (auto Module : Modules) {
    uint32_t Count = 0;
    CALL_ZE_RET_ERROR(zeModuleGetKernelNames, Module, &Count,
                      /*Names=*/nullptr);
    if (Count == 0)
      continue;

    llvm::SmallVector<const char *> Names(Count);
    CALL_ZE_RET_ERROR(zeModuleGetKernelNames, Module, &Count, Names.data());

    for (auto *Name : Names) {
      KernelsToModuleMap.emplace(Name, Module);
    }
  }

  return Plugin::success();
}

} // namespace llvm::omp::target::plugin