src/dawn/native/vulkan/BackendVk.h

// Copyright 2019 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
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#ifndef SRC_DAWN_NATIVE_VULKAN_BACKENDVK_H_
#define SRC_DAWN_NATIVE_VULKAN_BACKENDVK_H_

#include <mutex>
#include <string>
#include <vector>

#include "absl/container/flat_hash_map.h"
#include "src/dawn/common/DynamicLib.h"
#include "src/dawn/common/Ref.h"
#include "src/dawn/common/RefCounted.h"
#include "src/dawn/common/ityp_array.h"
#include "src/dawn/native/BackendConnection.h"
#include "src/dawn/native/vulkan/PhysicalDeviceVk.h"
#include "src/dawn/native/vulkan/VulkanFunctions.h"
#include "src/dawn/native/vulkan/VulkanInfo.h"

namespace dawn::native::vulkan {

// The required version of Vulkan the driver must support in order for Dawn to use the Vulkan
// backend. If this value is updated ensure that appropriate adjustments are made to
// VulkanExtensions.h/cpp and VulkanFunctions.h/cpp.
// Vulkan 1.1 is required due to poor quality of some Vulkan 1.0 drivers.
// See crbug.com/850881, crbug.com/863086, crbug.com/1465064, crbug.com/346990068
inline constexpr uint32_t kRequiredVulkanVersion = VK_API_VERSION_1_1;

enum class ICD : uint8_t {
    None,
    SwiftShader,
};
constexpr uint32_t kICDCount = 2u;

class Device;

// VulkanInstance holds the reference to the Vulkan library, the VkInstance, VkPhysicalDevices
// on that instance, Vulkan functions loaded from the library, and global information
// gathered from the instance. VkPhysicalDevices bound to the VkInstance are bound to the GPU
// and GPU driver, keeping them active. It is RefCounted so that (eventually) when all adapters
// on an instance are no longer in use, the instance is deleted. This can be particuarly useful
// when we create multiple instances to selectively discover ICDs (like only
// SwiftShader/iGPU/dGPU/eGPU), and only one physical device on one instance remains in use. We
// can delete the VkInstances that are not in use to avoid holding the discrete GPU active.
class VulkanInstance : public RefCounted {
  public:
    static ResultOrError<Ref<VulkanInstance>> Create(const InstanceBase* instance, ICD icd);
    ~VulkanInstance() override;

    const VulkanFunctions& GetFunctions() const;
    VkInstance GetVkInstance() const;
    const VulkanGlobalInfo& GetGlobalInfo() const;
    const std::vector<VkPhysicalDevice>& GetVkPhysicalDevices() const;

    // TODO(dawn:831): This set of functions guards may need to be adjusted when Dawn is updated
    // to support multithreading.
    void StartListeningForDeviceMessages(Device* device);
    void StopListeningForDeviceMessages(Device* device);
    bool HandleDeviceMessage(std::string deviceDebugPrefix, std::string message);

  private:
    VulkanInstance();

    MaybeError Initialize(const InstanceBase* instance, ICD icd);
    ResultOrError<VulkanGlobalKnobs> CreateVkInstance(const InstanceBase* instance);

    MaybeError RegisterDebugUtils();

    DynamicLib mVulkanLib;
    VulkanGlobalInfo mGlobalInfo = {};
    VkInstance mInstance = VK_NULL_HANDLE;
    VulkanFunctions mFunctions;

    VkDebugUtilsMessengerEXT mDebugUtilsMessenger = VK_NULL_HANDLE;

    std::vector<VkPhysicalDevice> mVkPhysicalDevices;

    // Devices keep the VulkanInstance alive, so as long as devices remove themselves from this
    // map on destruction the pointers it contains should remain valid.
    absl::flat_hash_map<std::string, Device*> mMessageListenerDevices;
    std::mutex mMessageListenerDevicesMutex;
};

class Backend : public BackendConnection {
  public:
    explicit Backend(InstanceBase* instance);
    ~Backend() override;

    MaybeError Initialize();

    std::vector<Ref<PhysicalDeviceBase>> DiscoverPhysicalDevices(
        const UnpackedPtr<RequestAdapterOptions>& options) override;

  private:
    ityp::bitset<ICD, kICDCount> mVulkanInstancesCreated = {};
    ityp::array<ICD, Ref<VulkanInstance>, kICDCount> mVulkanInstances = {};
    ityp::array<ICD, std::vector<Ref<PhysicalDevice>>, kICDCount> mPhysicalDevices = {};
};

}  // namespace dawn::native::vulkan

#endif  // SRC_DAWN_NATIVE_VULKAN_BACKENDVK_H_