//===--- HLSL.cpp - HLSL ToolChain Implementations --------------*- 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
//
//===----------------------------------------------------------------------===//

#include "HLSL.h"
#include "CommonArgs.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"

using namespace clang::driver;
using namespace clang::driver::tools;
using namespace clang::driver::toolchains;
using namespace clang;
using namespace llvm::opt;
using namespace llvm;

namespace {

const unsigned OfflineLibMinor = 0xF;

bool isLegalShaderModel(Triple &T) {
  if (T.getOS() != Triple::OSType::ShaderModel)
    return false;

  auto Version = T.getOSVersion();
  if (Version.getBuild())
    return false;
  if (Version.getSubminor())
    return false;

  auto Kind = T.getEnvironment();

  switch (Kind) {
  default:
    return false;
  case Triple::EnvironmentType::Vertex:
  case Triple::EnvironmentType::Hull:
  case Triple::EnvironmentType::Domain:
  case Triple::EnvironmentType::Geometry:
  case Triple::EnvironmentType::Pixel:
  case Triple::EnvironmentType::Compute: {
    VersionTuple MinVer(4, 0);
    return MinVer <= Version;
  } break;
  case Triple::EnvironmentType::Library: {
    VersionTuple SM6x(6, OfflineLibMinor);
    if (Version == SM6x)
      return true;

    VersionTuple MinVer(6, 3);
    return MinVer <= Version;
  } break;
  case Triple::EnvironmentType::Amplification:
  case Triple::EnvironmentType::Mesh: {
    VersionTuple MinVer(6, 5);
    return MinVer <= Version;
  } break;
  }
  return false;
}

std::string tryParseProfile(StringRef Profile) {
  // [ps|vs|gs|hs|ds|cs|ms|as]_[major]_[minor]
  SmallVector<StringRef, 3> Parts;
  Profile.split(Parts, "_");
  if (Parts.size() != 3)
    return "";

  Triple::EnvironmentType Kind =
      StringSwitch<Triple::EnvironmentType>(Parts[0])
          .Case("ps", Triple::EnvironmentType::Pixel)
          .Case("vs", Triple::EnvironmentType::Vertex)
          .Case("gs", Triple::EnvironmentType::Geometry)
          .Case("hs", Triple::EnvironmentType::Hull)
          .Case("ds", Triple::EnvironmentType::Domain)
          .Case("cs", Triple::EnvironmentType::Compute)
          .Case("lib", Triple::EnvironmentType::Library)
          .Case("ms", Triple::EnvironmentType::Mesh)
          .Case("as", Triple::EnvironmentType::Amplification)
          .Default(Triple::EnvironmentType::UnknownEnvironment);
  if (Kind == Triple::EnvironmentType::UnknownEnvironment)
    return "";

  unsigned long long Major = 0;
  if (llvm::getAsUnsignedInteger(Parts[1], 0, Major))
    return "";

  unsigned long long Minor = 0;
  if (Parts[2] == "x" && Kind == Triple::EnvironmentType::Library)
    Minor = OfflineLibMinor;
  else if (llvm::getAsUnsignedInteger(Parts[2], 0, Minor))
    return "";

  // dxil-unknown-shadermodel-hull
  llvm::Triple T;
  T.setArch(Triple::ArchType::dxil);
  T.setOSName(Triple::getOSTypeName(Triple::OSType::ShaderModel).str() +
              VersionTuple(Major, Minor).getAsString());
  T.setEnvironment(Kind);
  if (isLegalShaderModel(T))
    return T.getTriple();
  else
    return "";
}

} // namespace

/// DirectX Toolchain
HLSLToolChain::HLSLToolChain(const Driver &D, const llvm::Triple &Triple,
                             const ArgList &Args)
    : ToolChain(D, Triple, Args) {}

std::string
HLSLToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
                                           types::ID InputType) const {
  if (Arg *A = Args.getLastArg(options::OPT_target_profile)) {
    StringRef Profile = A->getValue();
    std::string Triple = tryParseProfile(Profile);
    if (Triple == "") {
      getDriver().Diag(diag::err_drv_invalid_directx_shader_module) << Profile;
      Triple = ToolChain::ComputeEffectiveClangTriple(Args, InputType);
    }
    A->claim();
    return Triple;
  } else {
    return ToolChain::ComputeEffectiveClangTriple(Args, InputType);
  }
}