WASI Assembler

A comprehensive toolchain for WebAssembly (Wasm) and the WebAssembly System Interface (WASI), supporting both binary .wasm and text .wat formats.

🏛️ Architecture

graph TB
    subgraph "Wasm/WASI Toolchain"
        A[Wasm/WAT Source] --> B[WASI Program Model]
        B --> C[Section Builder]
        C --> D[Instruction Encoder]
        D --> E["Wasm Binary (.wasm)"]
        
        subgraph "Section Types"
            F[Type / Import / Function]
            G[Memory / Global / Export]
            H[Code / Data / Custom]
        end
        
        C --> F
        C --> G
        C --> H
    end

🚀 Features

Core Capabilities

• Dual Format Support: Full support for reading and writing both binary .wasm files and text-based .wat representations.
• Component Model: (🚧) Experimental support for the Wasm Component Model, including component, core module, and alias definitions.
• Instruction Set: Comprehensive coverage of standard WebAssembly instructions, including numeric, control flow, and memory operations.

Advanced Features

• WASI Integration: Built-in support for defining WASI-specific imports and exports (e.g., wasi_snapshot_preview1).
• Section Management: Automatic layout and encoding of all standard Wasm sections, plus support for custom sections (e.g., for debugging).
• Validation: Includes a basic validator to ensure generated modules adhere to the WebAssembly specification.

💻 Usage

Assembling WAT to WASM

The following example demonstrates how to parse a WAT string and compile it into a WASM binary.

use wasi_assembler::WasiAssembler;
use std::fs;

fn main() {
    let wat_source = r#"
        (module
            (func $add (param $lhs i32) (param $rhs i32) (result i32)
                local.get $lhs
                local.get $rhs
                i32.add)
            (export "add" (func $add))
        )
    "#;

    let assembler = WasiAssembler::new();
    let binary = assembler.assemble_from_str(wat_source).expect("Failed to assemble WAT");

    fs::write("add.wasm", binary).unwrap();
    println!("Generated add.wasm");
}

🛠️ Support Status

Legend: ✅ Supported, 🚧 In Progress, ❌ Not Supported

🔗 Relations

• gaia-types: Uses BinaryWriter and LEB128 encoding utilities for compact Wasm binary generation.
• gaia-assembler: Acts as the primary WebAssembly backend for the Gaia project, enabling execution in browsers and WASI runtimes.