/* Copyright 2024 The OpenXLA Authors.

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.
==============================================================================*/

#ifndef XLA_SERVICE_LEGALIZE_SCHEDULING_ANNOTATIONS_H_
#define XLA_SERVICE_LEGALIZE_SCHEDULING_ANNOTATIONS_H_

#include <utility>
#include <vector>

#include "absl/container/btree_map.h"
#include "absl/container/flat_hash_map.h"
#include "absl/container/flat_hash_set.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "xla/hlo/ir/hlo_computation.h"
#include "xla/hlo/ir/hlo_module.h"
#include "xla/hlo/pass/hlo_pass_interface.h"
#include "xla/service/scheduling_annotations_util.h"
#include "xla/util.h"

namespace xla {

// Legalizer pass for scheduling annotations (to be used in
//  LatencyHidingScheduler).
class LegalizeSchedulingAnnotations : public HloModulePass {
 public:
  struct Config {
    HloPredicate keep_sync_annotation = HloPredicateTrue;
    HloPredicate keep_trivial_sync_annotation = HloPredicateTrue;
    bool propagate_annotation = false;
    bool check_start_done_annotation_consistency = true;
    bool remove_loop_iteration_annotation_only = false;
    bool run_verification = false;
  };

  explicit LegalizeSchedulingAnnotations(Config config)
      : config_(std::move(config)) {}
  absl::string_view name() const override {
    return "legalize-scheduling-annotations";
  }

  static absl::StatusOr<bool> PropagateAnnotations(
      const HloComputation* computation,
      const absl::btree_map<Annotation, std::vector<HloInstruction*>>&
          annotation_to_instruction);

  static absl::Status Verify(HloModule* module);

  using HloPassInterface::Run;
  absl::StatusOr<bool> Run(
      HloModule* module,
      const absl::flat_hash_set<absl::string_view>& execution_threads) override;

 private:
  bool KeepSchedulingAnnotation(HloInstruction* instr);
  bool RemoveTrivialGroups(
      const absl::flat_hash_map<
          Annotation,
          absl::flat_hash_map<HloComputation*, std::vector<HloInstruction*>>>&
          annotation_to_instruction);
  Config config_;
};
}  // namespace xla

#endif  // XLA_SERVICE_LEGALIZE_SCHEDULING_ANNOTATIONS_H_