/* Copyright 2023 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_BACKENDS_GPU_RUNTIME_ANNOTATION_H_
#define XLA_BACKENDS_GPU_RUNTIME_ANNOTATION_H_

#include <cstdint>
#include <optional>
#include <string>

#include "absl/container/flat_hash_map.h"
#include "xla/hlo/ir/hlo_instruction.h"
#include "xla/hlo/ir/hlo_module.h"
#include "tsl/profiler/lib/nvtx_utils.h"
#include "tsl/profiler/lib/scoped_annotation.h"

namespace xla::gpu {

// Prepared information for the top level NVTX/profiler range covering an
// HloModule
class ModuleAnnotation {
 public:
  explicit ModuleAnnotation(absl::string_view module_name);
  explicit ModuleAnnotation(const HloModule& mod);

  absl::string_view longest_op_name_prefix() const { return longest_prefix_; }
  explicit operator absl::string_view() const { return title_str_; }
  tsl::profiler::StringHandle title() const { return title_; }
  static uint64_t NvtxSchemaId();
  int32_t common_stack_frames() const { return common_stack_frames_; }

 private:
  friend void RangePush(tsl::profiler::ProfilerDomainHandle domain,
                        const ModuleAnnotation& annotation) {
    tsl::profiler::RangePush(domain, annotation.title(), annotation);
  }

  std::string longest_prefix_;
  std::string title_str_;
  tsl::profiler::StringHandle title_;
  tsl::profiler::StringHandle module_name_;
  tsl::profiler::StringHandle common_src_locations_{};
  int32_t module_id_{-1};
  int32_t common_stack_frames_{};
};

// Prepared information for a kernel/thunk/fusion/... within an HloModule
struct KernelAnnotation {
  KernelAnnotation(const ModuleAnnotation& module_annotation,
                   const HloInstruction& inst);

  explicit operator absl::string_view() const { return title_str; }
  static uint64_t NvtxSchemaId();

 private:
  friend void RangePush(tsl::profiler::ProfilerDomainHandle domain,
                        const KernelAnnotation& annotation) {
    tsl::profiler::RangePush(domain, annotation.title, annotation);
  }

  std::string title_str;
  tsl::profiler::StringHandle title;
  tsl::profiler::StringHandle hlo_dump;
  tsl::profiler::StringHandle src_locations;
  tsl::profiler::StringHandle called_hlo_dump;
};

// Parsed/prepared information for an HloModule that gets propagated to NVTX
// ranges/profilers/... at execution time.
struct ModuleAnnotations {
  explicit ModuleAnnotations(absl::string_view module_name);
  explicit ModuleAnnotations(const HloModule&);

  ModuleAnnotation top_level;
  absl::flat_hash_map<absl::string_view, KernelAnnotation> kernels;
};

//===----------------------------------------------------------------------===//
// Scoped RAII helper to set and restore thread local module annotations
//===----------------------------------------------------------------------===//

class ScopedModuleAnnotations {
 public:
  explicit ScopedModuleAnnotations(const ModuleAnnotations* annotations);
  ~ScopedModuleAnnotations();

 private:
  const ModuleAnnotations* restore_;
};

const ModuleAnnotations* GetCurrentModuleAnnotations();

std::optional<tsl::profiler::ScopedAnnotation> GetKernelAnnotation(
    absl::string_view profile_annotation);

}  // namespace xla::gpu

#endif  // XLA_BACKENDS_GPU_RUNTIME_ANNOTATION_H_