// Copyright 2021 The IREE Authors
//
// Licensed 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 "experimental/rocm/rocm_allocator.h"

#include <stddef.h>

#include "experimental/rocm/dynamic_symbols.h"
#include "experimental/rocm/rocm_buffer.h"
#include "experimental/rocm/status_util.h"
#include "iree/base/api.h"

typedef struct iree_hal_rocm_allocator_t {
  iree_hal_resource_t resource;
  iree_hal_device_t* base_device;
  iree_hal_rocm_context_wrapper_t* context;

  bool supports_concurrent_managed_access;

  IREE_STATISTICS(iree_hal_allocator_statistics_t statistics;)
} iree_hal_rocm_allocator_t;

static const iree_hal_allocator_vtable_t iree_hal_rocm_allocator_vtable;

static iree_hal_rocm_allocator_t* iree_hal_rocm_allocator_cast(
    iree_hal_allocator_t* base_value) {
  IREE_HAL_ASSERT_TYPE(base_value, &iree_hal_rocm_allocator_vtable);
  return (iree_hal_rocm_allocator_t*)base_value;
}

iree_status_t iree_hal_rocm_allocator_create(
    iree_hal_rocm_context_wrapper_t* context,
    iree_hal_allocator_t** out_allocator) {
  IREE_ASSERT_ARGUMENT(context);
  IREE_TRACE_ZONE_BEGIN(z0);

  // To support device-local + host-visible memory we need concurrent managed
  // access indicating that the host and devices can concurrently access the
  // device memory. If we don't have this feature then we fall back to forcing
  // all device-local + host-visible memory into host-local + device-visible
  // page-locked memory. The compiler tries to avoid this for high-traffic
  // buffers except for readback staging buffers.
  int supports_concurrent_managed_access = 0;
  IREE_RETURN_AND_END_ZONE_IF_ERROR(
      z0, ROCM_RESULT_TO_STATUS(
              context->syms,
              hipDeviceGetAttribute(&supports_concurrent_managed_access,
                                    hipDeviceAttributeConcurrentManagedAccess,
                                    context->rocm_device),
              "hipDeviceGetAttribute"));

  IREE_TRACE_ZONE_APPEND_TEXT(
      z0, supports_concurrent_managed_access
              ? "has CONCURRENT_MANAGED_ACCESS"
              : "no CONCURRENT_MANAGED_ACCESS (expect slow accesses on "
                "device-local + host-visible memory)");

  iree_hal_rocm_allocator_t* allocator = NULL;
  iree_status_t status = iree_allocator_malloc(
      context->host_allocator, sizeof(*allocator), (void**)&allocator);
  if (iree_status_is_ok(status)) {
    iree_hal_resource_initialize(&iree_hal_rocm_allocator_vtable,
                                 &allocator->resource);
    allocator->context = context;
    allocator->supports_concurrent_managed_access =
        supports_concurrent_managed_access != 0;
    *out_allocator = (iree_hal_allocator_t*)allocator;
  }

  IREE_TRACE_ZONE_END(z0);
  return status;
}

static void iree_hal_rocm_allocator_destroy(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator) {
  iree_hal_rocm_allocator_t* allocator =
      iree_hal_rocm_allocator_cast(base_allocator);
  iree_allocator_t host_allocator = allocator->context->host_allocator;
  IREE_TRACE_ZONE_BEGIN(z0);

  iree_allocator_free(host_allocator, allocator);

  IREE_TRACE_ZONE_END(z0);
}

static iree_allocator_t iree_hal_rocm_allocator_host_allocator(
    const iree_hal_allocator_t* IREE_RESTRICT base_allocator) {
  iree_hal_rocm_allocator_t* allocator =
      (iree_hal_rocm_allocator_t*)base_allocator;
  return allocator->context->host_allocator;
}

static iree_status_t iree_hal_rocm_allocator_trim(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator) {
  return iree_ok_status();
}

static void iree_hal_rocm_allocator_query_statistics(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    iree_hal_allocator_statistics_t* IREE_RESTRICT out_statistics) {
  IREE_STATISTICS({
    iree_hal_rocm_allocator_t* allocator =
        iree_hal_rocm_allocator_cast(base_allocator);
    memcpy(out_statistics, &allocator->statistics, sizeof(*out_statistics));
  });
}

static iree_status_t iree_hal_rocm_allocator_query_memory_heaps(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    iree_host_size_t capacity,
    iree_hal_allocator_memory_heap_t* IREE_RESTRICT heaps,
    iree_host_size_t* IREE_RESTRICT out_count) {
  const iree_host_size_t count = 3;
  if (out_count) *out_count = count;
  if (capacity < count) {
    // NOTE: lightweight as this is hit in normal pre-sizing usage.
    return iree_status_from_code(IREE_STATUS_OUT_OF_RANGE);
  }

  // NOTE: this is all a guess - someone who is familiar with rocm will want
  // to refine this further.

  // Don't think there's a query for these.
  // Max allocation size may be much smaller in certain memory types such as
  // page-locked memory and it'd be good to enforce that.
  const iree_device_size_t max_allocation_size = ~(iree_device_size_t)0;
  const iree_device_size_t min_alignment = 64;

  // Device-local memory (dispatch resources):
  heaps[0] = (iree_hal_allocator_memory_heap_t){
      .type = IREE_HAL_MEMORY_TYPE_DEVICE_LOCAL,
      .allowed_usage =
          IREE_HAL_BUFFER_USAGE_TRANSFER | IREE_HAL_BUFFER_USAGE_DISPATCH,
      .max_allocation_size = max_allocation_size,
      .min_alignment = min_alignment,
  };

  // Write-combined page-locked host-local memory (upload):
  heaps[1] = (iree_hal_allocator_memory_heap_t){
      .type =
          IREE_HAL_MEMORY_TYPE_HOST_LOCAL | IREE_HAL_MEMORY_TYPE_HOST_COHERENT,
      .allowed_usage =
          IREE_HAL_BUFFER_USAGE_TRANSFER | IREE_HAL_BUFFER_USAGE_MAPPING,
      .max_allocation_size = max_allocation_size,
      .min_alignment = min_alignment,
  };

  // Cached page-locked host-local memory (download):
  heaps[2] = (iree_hal_allocator_memory_heap_t){
      .type = IREE_HAL_MEMORY_TYPE_HOST_LOCAL |
              IREE_HAL_MEMORY_TYPE_HOST_COHERENT |
              IREE_HAL_MEMORY_TYPE_HOST_CACHED,
      .allowed_usage =
          IREE_HAL_BUFFER_USAGE_TRANSFER | IREE_HAL_BUFFER_USAGE_MAPPING,
      .max_allocation_size = max_allocation_size,
      .min_alignment = min_alignment,
  };

  return iree_ok_status();
}

static iree_hal_buffer_compatibility_t
iree_hal_rocm_allocator_query_buffer_compatibility(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    iree_hal_buffer_params_t* IREE_RESTRICT params,
    iree_device_size_t* IREE_RESTRICT allocation_size) {
  iree_hal_rocm_allocator_t* allocator =
      iree_hal_rocm_allocator_cast(base_allocator);

  // All buffers can be allocated on the heap.
  iree_hal_buffer_compatibility_t compatibility =
      IREE_HAL_BUFFER_COMPATIBILITY_ALLOCATABLE;

  if (iree_any_bit_set(params->usage, IREE_HAL_BUFFER_USAGE_TRANSFER)) {
    compatibility |= IREE_HAL_BUFFER_COMPATIBILITY_QUEUE_TRANSFER;
  }

  // Buffers can only be used on the queue if they are device visible.
  if (iree_all_bits_set(params->type, IREE_HAL_MEMORY_TYPE_DEVICE_VISIBLE)) {
    if (iree_any_bit_set(params->usage, IREE_HAL_BUFFER_USAGE_TRANSFER)) {
      compatibility |= IREE_HAL_BUFFER_COMPATIBILITY_QUEUE_TRANSFER;
    }
    if (iree_any_bit_set(params->usage,
                         IREE_HAL_BUFFER_USAGE_DISPATCH_STORAGE)) {
      compatibility |= IREE_HAL_BUFFER_COMPATIBILITY_QUEUE_DISPATCH;
    }
  }

  if (iree_all_bits_set(params->type, IREE_HAL_MEMORY_TYPE_DEVICE_LOCAL |
                                          IREE_HAL_MEMORY_TYPE_HOST_VISIBLE)) {
    compatibility |= IREE_HAL_BUFFER_COMPATIBILITY_LOW_PERFORMANCE;
    // If concurrent managed access is not supported then make device-local +
    // host-visible allocations fall back to host-local + device-visible
    // page-locked memory. This will be significantly slower for the device to
    // access but the compiler only uses this type for readback staging buffers
    // and it's better to function than function fast.
    if (!allocator->supports_concurrent_managed_access) {
      params->type &= ~(IREE_HAL_MEMORY_TYPE_DEVICE_LOCAL |
                        IREE_HAL_MEMORY_TYPE_HOST_VISIBLE);
      params->type |=
          IREE_HAL_MEMORY_TYPE_HOST_LOCAL | IREE_HAL_MEMORY_TYPE_DEVICE_VISIBLE;
    }
  }

  // We are now optimal.
  params->type &= ~IREE_HAL_MEMORY_TYPE_OPTIMAL;

  // Guard against the corner case where the requested buffer size is 0. The
  // application is unlikely to do anything when requesting a 0-byte buffer; but
  // it can happen in real world use cases. So we should at least not crash.
  if (*allocation_size == 0) *allocation_size = 4;

  return compatibility;
}

static void iree_hal_rocm_buffer_free(iree_hal_rocm_context_wrapper_t* context,
                                      iree_hal_memory_type_t memory_type,
                                      hipDeviceptr_t device_ptr,
                                      void* host_ptr) {
  if (iree_all_bits_set(memory_type, IREE_HAL_MEMORY_TYPE_DEVICE_LOCAL)) {
    // Device local.
    ROCM_IGNORE_ERROR(context->syms, hipFree(device_ptr));
  } else {
    // Host local.
    ROCM_IGNORE_ERROR(context->syms, hipHostFree(host_ptr));
  }
}

static iree_status_t iree_hal_rocm_allocator_allocate_buffer(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    const iree_hal_buffer_params_t* IREE_RESTRICT params,
    iree_device_size_t allocation_size,
    iree_hal_buffer_t** IREE_RESTRICT out_buffer) {
  iree_hal_rocm_allocator_t* allocator =
      iree_hal_rocm_allocator_cast(base_allocator);
  // Coerce options into those required by the current device.
  iree_hal_buffer_params_t compat_params = *params;
  if (!iree_all_bits_set(iree_hal_rocm_allocator_query_buffer_compatibility(
                             base_allocator, &compat_params, &allocation_size),
                         IREE_HAL_BUFFER_COMPATIBILITY_ALLOCATABLE)) {
    return iree_make_status(
        IREE_STATUS_INVALID_ARGUMENT,
        "allocator cannot allocate a buffer with the given parameters");
  }

  iree_status_t status = iree_ok_status();
  void* host_ptr = NULL;
  hipDeviceptr_t device_ptr = 0;
  if (iree_all_bits_set(compat_params.type,
                        IREE_HAL_MEMORY_TYPE_DEVICE_LOCAL)) {
    // Device local case.
    if (iree_all_bits_set(compat_params.type,
                          IREE_HAL_MEMORY_TYPE_HOST_VISIBLE)) {
      status = ROCM_RESULT_TO_STATUS(
          allocator->context->syms,
          hipMallocManaged(&device_ptr, allocation_size, hipMemAttachGlobal));
      if (iree_status_is_ok(status) &&
          allocator->supports_concurrent_managed_access) {
        // Prefetch the buffer on the GPU device.
        status = ROCM_RESULT_TO_STATUS(
            allocator->context->syms,
            hipMemPrefetchAsync(device_ptr, allocation_size,
                                allocator->context->rocm_device,
                                allocator->context->rocm_stream));
      }
      host_ptr = (void*)device_ptr;
    } else {
      // Device only.
      status = ROCM_RESULT_TO_STATUS(allocator->context->syms,
                                     hipMalloc(&device_ptr, allocation_size));
    }
  } else {
    unsigned int flags = hipHostMallocMapped;
    if (!iree_all_bits_set(compat_params.type,
                           IREE_HAL_MEMORY_TYPE_HOST_CACHED)) {
      flags |= hipHostMallocWriteCombined;
    }
    status = ROCM_RESULT_TO_STATUS(
        allocator->context->syms,
        hipMemAllocHost(&host_ptr, allocation_size, flags));
    if (iree_status_is_ok(status)) {
      status = ROCM_RESULT_TO_STATUS(
          allocator->context->syms,
          hipHostGetDevicePointer(&device_ptr, host_ptr, /*flags=*/0));
    }
  }

  iree_hal_buffer_t* buffer = NULL;
  if (iree_status_is_ok(status)) {
    status = iree_hal_rocm_buffer_wrap(
        (iree_hal_allocator_t*)allocator, compat_params.type,
        compat_params.access, compat_params.usage, allocation_size,
        /*byte_offset=*/0,
        /*byte_length=*/allocation_size, device_ptr, host_ptr, &buffer);
  }

  if (iree_status_is_ok(status)) {
    IREE_STATISTICS(iree_hal_allocator_statistics_record_alloc(
        &allocator->statistics, compat_params.type, allocation_size));
    *out_buffer = buffer;
  } else {
    if (!buffer) {
      iree_hal_rocm_buffer_free(allocator->context, compat_params.type,
                                device_ptr, host_ptr);
    } else {
      iree_hal_buffer_release(buffer);
    }
  }
  return status;
}

static void iree_hal_rocm_allocator_deallocate_buffer(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    iree_hal_buffer_t* IREE_RESTRICT base_buffer) {
  iree_hal_rocm_allocator_t* allocator =
      iree_hal_rocm_allocator_cast(base_allocator);

  iree_hal_memory_type_t memory_type = iree_hal_buffer_memory_type(base_buffer);
  iree_hal_rocm_buffer_free(allocator->context, memory_type,
                            iree_hal_rocm_buffer_device_pointer(base_buffer),
                            iree_hal_rocm_buffer_host_pointer(base_buffer));

  IREE_STATISTICS(iree_hal_allocator_statistics_record_free(
      &allocator->statistics, memory_type,
      iree_hal_buffer_allocation_size(base_buffer)));

  iree_hal_buffer_destroy(base_buffer);
}

static iree_status_t iree_hal_rocm_allocator_import_buffer(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    const iree_hal_buffer_params_t* IREE_RESTRICT params,
    iree_hal_external_buffer_t* IREE_RESTRICT external_buffer,
    iree_hal_buffer_release_callback_t release_callback,
    iree_hal_buffer_t** IREE_RESTRICT out_buffer) {
  return iree_make_status(IREE_STATUS_UNAVAILABLE,
                          "importing from external buffers not supported");
}

static iree_status_t iree_hal_rocm_allocator_export_buffer(
    iree_hal_allocator_t* IREE_RESTRICT base_allocator,
    iree_hal_buffer_t* IREE_RESTRICT buffer,
    iree_hal_external_buffer_type_t requested_type,
    iree_hal_external_buffer_flags_t requested_flags,
    iree_hal_external_buffer_t* IREE_RESTRICT out_external_buffer) {
  return iree_make_status(IREE_STATUS_UNAVAILABLE,
                          "exporting to external buffers not supported");
}

static const iree_hal_allocator_vtable_t iree_hal_rocm_allocator_vtable = {
    .destroy = iree_hal_rocm_allocator_destroy,
    .host_allocator = iree_hal_rocm_allocator_host_allocator,
    .trim = iree_hal_rocm_allocator_trim,
    .query_statistics = iree_hal_rocm_allocator_query_statistics,
    .query_memory_heaps = iree_hal_rocm_allocator_query_memory_heaps,
    .query_buffer_compatibility =
        iree_hal_rocm_allocator_query_buffer_compatibility,
    .allocate_buffer = iree_hal_rocm_allocator_allocate_buffer,
    .deallocate_buffer = iree_hal_rocm_allocator_deallocate_buffer,
    .import_buffer = iree_hal_rocm_allocator_import_buffer,
    .export_buffer = iree_hal_rocm_allocator_export_buffer,
};