metal2vulkan

Alpha. This project is early and under active development. The public API, CLI flags, reflection layout details, and SPIR-V output may change without a stable semver guarantee while the crate is in the 0.x series. Treat it as research-quality: useful for experimentation and integration pilots, not a frozen interface.

Translate Metal AIR (LLVM bitcode / sanitized .ll) to Vulkan SPIR-V using a native Rust emitter. Production translation does not invoke LLVM llc.

Features

• Native AIR/LLVM-IR → OpCapability Shader / Logical GLSL450 SPIR-V
• Stage interface lowering for vertex, fragment, compute (kernel), and passthrough
• Library API plus a CLI compatible with simple in → out.spv harnesses
• Optional serde feature for reflection metadata JSON
• Optional workspace package for local Metal oracle / Vulkan executor experiments

Install

# CLI
cargo install metal2vulkan

# Library (Cargo.toml)
metal2vulkan = "0.1"

CLI

metal2vulkan <in.air|.ll> <out.spv> --stage vertex|fragment|passthrough|kernel
# optional interface metadata JSON (requires --features serde)
metal2vulkan in.ll out.spv --stage kernel --emit-meta out.json

• Success: prints a line containing PASS, writes SPIR-V, exits 0
• Failure: prints FALLBACK, exits non-zero

On failure the CLI writes a repro bundle under $TMPDIR/metal2vulkan-repros (override with METAL2VULKAN_REPRO_DIR).

Example

cargo run --example translate_native -- path/to/shader.ll kernel out.spv

Library

use metal2vulkan::passes::Stage;
use std::path::Path;

fn translate_ll(sanitized_ll: &str) -> Result<Vec<u8>, String> {
    let tmp = std::env::temp_dir().join("m2v-scratch");
    std::fs::create_dir_all(&tmp).ok();
    metal2vulkan::translate_sanitized_native(sanitized_ll, Stage::Kernel, Path::new(&tmp))
}

See crate docs (cargo doc --open), docs/ARCHITECTURE.md for the pipeline, and docs/REFLECTION.md for how consumers read binding metadata after a convert. Repository layout and the developer loop are in CONTRIBUTING.md. How to stay confident while refactoring (harvest, hash ledgers, A/B) is in docs/VALIDATION.md.

Coverage policy

Grammar and lowering behavior is locked with synthetic Rust tests. This repository does not ship third-party captured shaders. Prefer reduced .ll fixtures that name structural properties. Optional private system-metallib harvest and hash-only drift pins are documented in docs/VALIDATION.md.

spirv-val coverage is not the same as correct end-to-end pixels.

License

Licensed under the GNU Lesser General Public License v3.0 or later (LGPL-3.0-or-later).