// Copyright (c) 2019 The Khronos Group Inc.
// Copyright (c) 2019 Valve Corporation
// Copyright (c) 2019 LunarG Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "relax_float_ops_pass.h"

#include "source/opt/ir_builder.h"

namespace spvtools {
namespace opt {

bool RelaxFloatOpsPass::IsRelaxable(Instruction* inst) {
  return target_ops_core_f_rslt_.count(inst->opcode()) != 0 ||
         target_ops_core_f_opnd_.count(inst->opcode()) != 0 ||
         sample_ops_.count(inst->opcode()) != 0 ||
         (inst->opcode() == SpvOpExtInst &&
          inst->GetSingleWordInOperand(0) ==
              context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450() &&
          target_ops_450_.count(inst->GetSingleWordInOperand(1)) != 0);
}

bool RelaxFloatOpsPass::IsFloat32(Instruction* inst) {
  uint32_t ty_id;
  if (target_ops_core_f_opnd_.count(inst->opcode()) != 0) {
    uint32_t opnd_id = inst->GetSingleWordInOperand(0);
    Instruction* opnd_inst = get_def_use_mgr()->GetDef(opnd_id);
    ty_id = opnd_inst->type_id();
  } else {
    ty_id = inst->type_id();
    if (ty_id == 0) return false;
  }
  return IsFloat(ty_id, 32);
}

bool RelaxFloatOpsPass::IsRelaxed(uint32_t r_id) {
  for (auto r_inst : get_decoration_mgr()->GetDecorationsFor(r_id, false))
    if (r_inst->opcode() == SpvOpDecorate &&
        r_inst->GetSingleWordInOperand(1) == SpvDecorationRelaxedPrecision)
      return true;
  return false;
}

bool RelaxFloatOpsPass::ProcessInst(Instruction* r_inst) {
  uint32_t r_id = r_inst->result_id();
  if (r_id == 0) return false;
  if (!IsFloat32(r_inst)) return false;
  if (IsRelaxed(r_id)) return false;
  if (!IsRelaxable(r_inst)) return false;
  get_decoration_mgr()->AddDecoration(r_id, SpvDecorationRelaxedPrecision);
  return true;
}

bool RelaxFloatOpsPass::ProcessFunction(Function* func) {
  bool modified = false;
  cfg()->ForEachBlockInReversePostOrder(
      func->entry().get(), [&modified, this](BasicBlock* bb) {
        for (auto ii = bb->begin(); ii != bb->end(); ++ii)
          modified |= ProcessInst(&*ii);
      });
  return modified;
}

Pass::Status RelaxFloatOpsPass::ProcessImpl() {
  Pass::ProcessFunction pfn = [this](Function* fp) {
    return ProcessFunction(fp);
  };
  bool modified = context()->ProcessEntryPointCallTree(pfn);
  return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}

Pass::Status RelaxFloatOpsPass::Process() {
  Initialize();
  return ProcessImpl();
}

void RelaxFloatOpsPass::Initialize() {
  target_ops_core_f_rslt_ = {
      SpvOpLoad,
      SpvOpPhi,
      SpvOpVectorExtractDynamic,
      SpvOpVectorInsertDynamic,
      SpvOpVectorShuffle,
      SpvOpCompositeExtract,
      SpvOpCompositeConstruct,
      SpvOpCompositeInsert,
      SpvOpCopyObject,
      SpvOpTranspose,
      SpvOpConvertSToF,
      SpvOpConvertUToF,
      SpvOpFConvert,
      // SpvOpQuantizeToF16,
      SpvOpFNegate,
      SpvOpFAdd,
      SpvOpFSub,
      SpvOpFMul,
      SpvOpFDiv,
      SpvOpFMod,
      SpvOpVectorTimesScalar,
      SpvOpMatrixTimesScalar,
      SpvOpVectorTimesMatrix,
      SpvOpMatrixTimesVector,
      SpvOpMatrixTimesMatrix,
      SpvOpOuterProduct,
      SpvOpDot,
      SpvOpSelect,
  };
  target_ops_core_f_opnd_ = {
      SpvOpFOrdEqual,
      SpvOpFUnordEqual,
      SpvOpFOrdNotEqual,
      SpvOpFUnordNotEqual,
      SpvOpFOrdLessThan,
      SpvOpFUnordLessThan,
      SpvOpFOrdGreaterThan,
      SpvOpFUnordGreaterThan,
      SpvOpFOrdLessThanEqual,
      SpvOpFUnordLessThanEqual,
      SpvOpFOrdGreaterThanEqual,
      SpvOpFUnordGreaterThanEqual,
  };
  target_ops_450_ = {
      GLSLstd450Round, GLSLstd450RoundEven, GLSLstd450Trunc, GLSLstd450FAbs,
      GLSLstd450FSign, GLSLstd450Floor, GLSLstd450Ceil, GLSLstd450Fract,
      GLSLstd450Radians, GLSLstd450Degrees, GLSLstd450Sin, GLSLstd450Cos,
      GLSLstd450Tan, GLSLstd450Asin, GLSLstd450Acos, GLSLstd450Atan,
      GLSLstd450Sinh, GLSLstd450Cosh, GLSLstd450Tanh, GLSLstd450Asinh,
      GLSLstd450Acosh, GLSLstd450Atanh, GLSLstd450Atan2, GLSLstd450Pow,
      GLSLstd450Exp, GLSLstd450Log, GLSLstd450Exp2, GLSLstd450Log2,
      GLSLstd450Sqrt, GLSLstd450InverseSqrt, GLSLstd450Determinant,
      GLSLstd450MatrixInverse,
      // TODO(greg-lunarg): GLSLstd450ModfStruct,
      GLSLstd450FMin, GLSLstd450FMax, GLSLstd450FClamp, GLSLstd450FMix,
      GLSLstd450Step, GLSLstd450SmoothStep, GLSLstd450Fma,
      // TODO(greg-lunarg): GLSLstd450FrexpStruct,
      GLSLstd450Ldexp, GLSLstd450Length, GLSLstd450Distance, GLSLstd450Cross,
      GLSLstd450Normalize, GLSLstd450FaceForward, GLSLstd450Reflect,
      GLSLstd450Refract, GLSLstd450NMin, GLSLstd450NMax, GLSLstd450NClamp};
  sample_ops_ = {SpvOpImageSampleImplicitLod,
                 SpvOpImageSampleExplicitLod,
                 SpvOpImageSampleDrefImplicitLod,
                 SpvOpImageSampleDrefExplicitLod,
                 SpvOpImageSampleProjImplicitLod,
                 SpvOpImageSampleProjExplicitLod,
                 SpvOpImageSampleProjDrefImplicitLod,
                 SpvOpImageSampleProjDrefExplicitLod,
                 SpvOpImageFetch,
                 SpvOpImageGather,
                 SpvOpImageDrefGather,
                 SpvOpImageRead,
                 SpvOpImageSparseSampleImplicitLod,
                 SpvOpImageSparseSampleExplicitLod,
                 SpvOpImageSparseSampleDrefImplicitLod,
                 SpvOpImageSparseSampleDrefExplicitLod,
                 SpvOpImageSparseSampleProjImplicitLod,
                 SpvOpImageSparseSampleProjExplicitLod,
                 SpvOpImageSparseSampleProjDrefImplicitLod,
                 SpvOpImageSparseSampleProjDrefExplicitLod,
                 SpvOpImageSparseFetch,
                 SpvOpImageSparseGather,
                 SpvOpImageSparseDrefGather,
                 SpvOpImageSparseTexelsResident,
                 SpvOpImageSparseRead};
}

}  // namespace opt
}  // namespace spvtools