https://github.com/pulseengine/loom
Loom — Formally verified WebAssembly optimizer. Part of the PulseEngine toolchain.
https://github.com/pulseengine/loom
Last synced: 3 months ago
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Loom — Formally verified WebAssembly optimizer. Part of the PulseEngine toolchain.
- Host: GitHub
- URL: https://github.com/pulseengine/loom
- Owner: pulseengine
- License: apache-2.0
- Created: 2025-11-10T18:09:14.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2026-02-28T20:13:33.000Z (3 months ago)
- Last Synced: 2026-02-28T23:28:34.140Z (3 months ago)
- Language: Rust
- Size: 1.26 MB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
README
# Loom
Formally verified WebAssembly optimizer
[](https://github.com/pulseengine/loom/actions/workflows/ci.yml)
Meld
·
Loom
·
Synth
·
Kiln
·
Sigil
Meld fuses. Loom weaves. Synth transpiles. Kiln fires. Sigil seals.
Twelve-pass WebAssembly optimization pipeline built on Cranelift's ISLE pattern-matching engine. Constant folding, strength reduction, CSE, inlining, dead code elimination — each pass proven correct through Z3 SMT translation validation. Includes a fused mode purpose-built for Meld output.
Loom consistently achieves 80-95% binary size reduction with 10-30 microsecond optimization times. The entire pipeline is pure Rust with minimal dependencies.
## Quick Start
```bash
# Build from source
git clone https://github.com/pulseengine/loom
cd loom
cargo build --release
# Optimize a WebAssembly module
loom optimize input.wasm -o output.wasm
# With statistics
loom optimize input.wasm -o output.wasm --stats
# With Z3 verification
loom optimize input.wasm -o output.wasm --verify
```
## Architecture
- **loom-core** — Optimization pipeline implementation
- **loom-shared** — Core ISLE definitions and WebAssembly IR (stable API)
- **loom-cli** — Command-line interface
- **loom-testing** — Differential testing framework
The 12-phase pipeline: Precompute, ISLE Constant Folding, Strength Reduction, CSE, Function Inlining, ISLE (Post-inline), Code Folding, LICM, Branch Simplification, Dead Code Elimination, Block Merging, Vacuum and Simplify Locals.
See [docs/architecture.md](docs/architecture.md) for the full pipeline design.
## Features
- **Constant folding** — Compile-time evaluation with cross-function propagation via inlining
- **Strength reduction** — Replace expensive ops with cheaper equivalents (`x * 8` becomes `x << 3`)
- **Common subexpression elimination** — Deduplicate redundant computations
- **Function inlining** — Inline small functions to expose cross-function optimizations
- **Dead code elimination** — Remove unreachable code and unused locals
- **Loop-invariant code motion** — Hoist invariant expressions out of loops
- **Component Model support** — wasm32-wasip2 build target
- **Stateful dataflow analysis** — Track locals and memory state across passes
- **Idempotent passes** — Safe to run multiple times without degradation
## Formal Verification
Loom supports two verification modes:
**Property-Based (Always Available)**
```bash
loom optimize input.wasm -o output.wasm --verify
```
Fast idempotence checks and constant folding validation with ~5ms overhead.
**Z3 SMT Formal Proof (Optional)**
```bash
cargo build --release --features verification
loom optimize input.wasm -o output.wasm --verify
```
Proves mathematically that optimizations preserve program semantics via translation validation. See [docs/guides/formal-verification.md](docs/guides/formal-verification.md) for details.
> [!NOTE]
> **Cross-cutting verification** — Rocq mechanized proofs, Kani bounded model checking, Z3 SMT verification, and Verus Rust verification are used across the PulseEngine toolchain. Sigil attestation chains bind it all together.
## Documentation
- [Usage Guide](docs/guides/usage.md) — Complete CLI reference and best practices
- [Quick Reference](docs/guides/quick-reference.md) — Cheat sheet for common tasks
- [Architecture](docs/architecture.md) — Deep dive into the 12-phase pipeline
- [Formal Verification](docs/guides/formal-verification.md) — Z3 SMT verification internals
- [WASM Build](docs/guides/wasm-build.md) — Building Loom to WebAssembly
- [Fused Component Optimization](docs/design/fused-component-optimization.md) — Meld-Loom pipeline
- [Contributing](CONTRIBUTING.md) — How to contribute
## Building
```bash
cargo build --release # Standard build
cargo build --release --features verification # With Z3 verification
cargo test # Run tests
cargo bench # Run benchmarks
bazel build //loom-cli:loom_wasm --platforms=@rules_rust//rust/platform:wasm # WASM build
```
## License
Apache-2.0
---
Part of PulseEngine — formally verified WebAssembly toolchain for safety-critical systems