llama-gguf 0.2.0

//! Vulkan GPU backend for tensor operations
//!
//! This module provides a Vulkan-based GPU implementation of the Backend trait.
//! Vulkan enables cross-platform GPU compute on Windows, Linux, macOS (via MoltenVK),
//! and Android.
//!
//! # Features
//! - Cross-platform GPU compute
//! - SPIR-V shader compilation
//! - Memory management via gpu-allocator
//! - Async compute with synchronization
//!
//! # Requirements
//! - Vulkan 1.2+ capable GPU
//! - Vulkan SDK/runtime installed
//! - Build with `--features vulkan`

#[cfg(feature = "vulkan")]
mod context;
#[cfg(feature = "vulkan")]
mod ops;

use crate::backend::{Backend, BackendError, BackendResult};
use crate::tensor::{DType, Tensor};

/// Vulkan backend configuration
#[derive(Debug, Clone)]
pub struct VulkanConfig {
    /// Device index to use (0 = first GPU)
    pub device_index: usize,
    /// Maximum memory to allocate (in bytes, 0 = no limit)
    pub max_memory: usize,
    /// Enable validation layers (for debugging)
    pub enable_validation: bool,
    /// Preferred queue family for compute
    pub compute_queue_family: Option<u32>,
}

impl Default for VulkanConfig {
    fn default() -> Self {
        Self {
            device_index: 0,
            max_memory: 0,
            enable_validation: cfg!(debug_assertions),
            compute_queue_family: None,
        }
    }
}

/// Vulkan GPU backend
///
/// This is a stub implementation. The full implementation requires:
/// - ash for Vulkan API bindings
/// - gpu-allocator for memory management
/// - SPIR-V shaders for compute operations
#[derive(Debug)]
pub struct VulkanBackend {
    config: VulkanConfig,
    available: bool,
    device_name: String,
    compute_capability: ComputeCapability,
}

/// Vulkan compute capability information
#[derive(Debug, Clone, Default)]
pub struct ComputeCapability {
    /// Maximum workgroup size (x * y * z)
    pub max_workgroup_size: [u32; 3],
    /// Maximum workgroup count
    pub max_workgroup_count: [u32; 3],
    /// Maximum shared memory per workgroup
    pub max_shared_memory: u32,
    /// Whether 16-bit float is supported
    pub supports_fp16: bool,
    /// Whether subgroup operations are supported
    pub supports_subgroups: bool,
}

impl VulkanBackend {
    /// Create a new Vulkan backend with default configuration
    pub fn new() -> Self {
        Self::with_config(VulkanConfig::default())
    }

    /// Create a Vulkan backend with custom configuration
    pub fn with_config(config: VulkanConfig) -> Self {
        // In a full implementation, this would:
        // 1. Create Vulkan instance
        // 2. Enumerate physical devices
        // 3. Select device based on config
        // 4. Create logical device and queues
        // 5. Set up memory allocator
        // 6. Load compute shaders

        #[cfg(feature = "vulkan")]
        {
            // Attempt to initialize Vulkan
            // This is where the real implementation would go
            Self {
                config,
                available: false, // Set to true when properly initialized
                device_name: "Vulkan GPU (not initialized)".to_string(),
                compute_capability: ComputeCapability::default(),
            }
        }

        #[cfg(not(feature = "vulkan"))]
        {
            Self {
                config,
                available: false,
                device_name: "Vulkan disabled (compile with --features vulkan)".to_string(),
                compute_capability: ComputeCapability::default(),
            }
        }
    }

    /// Get device name
    pub fn device_name(&self) -> &str {
        &self.device_name
    }

    /// Get compute capability
    pub fn compute_capability(&self) -> &ComputeCapability {
        &self.compute_capability
    }

    /// Get configuration
    pub fn config(&self) -> &VulkanConfig {
        &self.config
    }

    /// Enumerate available Vulkan devices
    pub fn enumerate_devices() -> Vec<VulkanDeviceInfo> {
        #[cfg(feature = "vulkan")]
        {
            // In a full implementation, this would use ash to enumerate devices
            vec![]
        }

        #[cfg(not(feature = "vulkan"))]
        {
            vec![]
        }
    }
}

/// Information about a Vulkan-capable device
#[derive(Debug, Clone)]
pub struct VulkanDeviceInfo {
    /// Device name
    pub name: String,
    /// Device type (discrete, integrated, etc.)
    pub device_type: VulkanDeviceType,
    /// Available VRAM in bytes
    pub vram_bytes: u64,
    /// Vulkan API version supported
    pub api_version: (u32, u32, u32),
    /// Driver version
    pub driver_version: u32,
}

/// Vulkan device type
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum VulkanDeviceType {
    DiscreteGpu,
    IntegratedGpu,
    VirtualGpu,
    Cpu,
    Other,
}

impl Default for VulkanBackend {
    fn default() -> Self {
        Self::new()
    }
}

impl Backend for VulkanBackend {
    fn name(&self) -> &str {
        "vulkan"
    }

    fn is_available(&self) -> bool {
        self.available
    }

    fn alloc(&self, shape: &[usize], dtype: DType) -> BackendResult<Tensor> {
        if !self.available {
            return Err(BackendError::NotAvailable("Vulkan".to_string()));
        }

        // In a full implementation, this would allocate GPU memory
        // For now, fall back to CPU allocation
        Ok(Tensor::zeros(shape.to_vec(), dtype))
    }

    fn copy_to(&self, tensor: &Tensor) -> BackendResult<Tensor> {
        if !self.available {
            return Err(BackendError::NotAvailable("Vulkan".to_string()));
        }

        // In a full implementation, this would copy to GPU memory
        Ok(tensor.clone())
    }

    fn add(&self, a: &Tensor, b: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan add".to_string()))
    }

    fn mul(&self, a: &Tensor, b: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan mul".to_string()))
    }

    fn scale(&self, a: &Tensor, scalar: f32, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan scale".to_string()))
    }

    fn silu(&self, x: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan silu".to_string()))
    }

    fn gelu(&self, x: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan gelu".to_string()))
    }

    fn softmax(&self, x: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan softmax".to_string()))
    }

    fn rms_norm(
        &self,
        x: &Tensor,
        weight: &Tensor,
        eps: f32,
        out: &mut Tensor,
    ) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan rms_norm".to_string()))
    }

    fn matmul(&self, a: &Tensor, b: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan matmul".to_string()))
    }

    fn matvec(&self, a: &Tensor, b: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan matvec".to_string()))
    }

    fn dequantize(&self, src: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan dequantize".to_string()))
    }

    fn matvec_q(&self, a: &Tensor, b: &Tensor, out: &mut Tensor) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan matvec_q".to_string()))
    }

    fn rope(
        &self,
        q: &mut Tensor,
        k: &mut Tensor,
        pos: usize,
        freq_base: f32,
        freq_scale: f32,
        _use_neox: bool,
    ) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan rope".to_string()))
    }

    fn attention(
        &self,
        q: &Tensor,
        k: &Tensor,
        v: &Tensor,
        out: &mut Tensor,
        scale: f32,
    ) -> BackendResult<()> {
        Err(BackendError::NotAvailable("Vulkan attention".to_string()))
    }
}

/// SPIR-V shader source (would be compiled at build time)
pub mod shaders {
    /// Element-wise addition shader
    pub const ADD_SPIRV: &[u8] = &[];

    /// Element-wise multiplication shader
    pub const MUL_SPIRV: &[u8] = &[];

    /// Matrix-vector multiply shader
    pub const MATVEC_SPIRV: &[u8] = &[];

    /// Softmax shader
    pub const SOFTMAX_SPIRV: &[u8] = &[];

    /// RMS normalization shader
    pub const RMS_NORM_SPIRV: &[u8] = &[];

    /// SiLU activation shader
    pub const SILU_SPIRV: &[u8] = &[];

    /// Dequantization shaders
    pub const DEQUANT_Q4_0_SPIRV: &[u8] = &[];
    pub const DEQUANT_Q8_0_SPIRV: &[u8] = &[];
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_vulkan_backend_creation() {
        let backend = VulkanBackend::new();
        assert_eq!(backend.name(), "vulkan");
        // Will be false without proper Vulkan setup
    }

    #[test]
    fn test_vulkan_config_default() {
        let config = VulkanConfig::default();
        assert_eq!(config.device_index, 0);
        assert_eq!(config.max_memory, 0);
    }

    #[test]
    fn test_vulkan_enumerate_devices() {
        let devices = VulkanBackend::enumerate_devices();
        // May be empty if no Vulkan devices
        println!("Found {} Vulkan devices", devices.len());
    }
}