> ## Documentation Index > Fetch the complete documentation index at: https://docs.stoffelmpc.com/llms.txt > Use this file to discover all available pages before exploring further. # Compilation > How StoffelLang source is validated, compiled, optimized, disassembled, and executed in current Stoffel programs. StoffelLang source files (`.stfl`) compile to portable Stoffel bytecode files (`.stflb`). The current compiler lives in `crates/stoffel-lang`; the primary user-facing entry points are the `stoffel` CLI and Rust SDK. ## Pipeline Compilation pipeline from StoffelLang source through parsing, type checking, lowering, optimization, and .stflb bytecode. The compiler validates `.stfl` source, lowers it to VM function metadata and instructions, then writes the `.stflb` artifact that the CLI, SDK, and VM can load. ## Validate without writing bytecode ```bash theme={null} stoffel check stoffel check src/main.stfl stoffel check src stoffel check --print-ir ``` `check` reads project defaults from `Stoffel.toml` unless you pass a source path. MPC settings can be overridden: ```bash theme={null} stoffel check --backend honeybadger --field bls12-381 --parties 5 --threshold 1 ``` ## Build a project ```bash theme={null} stoffel build stoffel build --release stoffel build --print-ir ``` `build` writes bytecode under `target/debug` or `target/release`. ## Compile a source file ```bash theme={null} stoffel compile src/main.stfl --output target/debug/main.stflb stoffel compile src/main.stfl -O3 --output target/release/main.stflb ``` When compiling one selected source file, use `--output` to choose the bytecode path. ## Optimization flags ```bash theme={null} stoffel compile src/main.stfl -O0 --output target/debug/main.stflb stoffel compile src/main.stfl -O 2 --output target/debug/main.stflb stoffel compile src/main.stfl --opt-level 3 --output target/release/main.stflb stoffel build --optimize stoffel build --release ``` `--optimize` uses O2 unless `--release` selects O3. `--release` writes under `target/release` and uses O3 unless `--opt-level` is set. ## Disassemble bytecode ```bash theme={null} stoffel compile --disassemble target/debug/main.stflb ``` Use disassembly to confirm generated functions, instructions, and metadata before debugging runtime behavior. ## Run after compiling ```bash theme={null} stoffel run target/debug/main.stflb --entry main stoffel run src/main.stfl --input a=40 --input b=2 stoffel run --program-info ``` For local MPC runs, use the CLI local MPC path and provide any required client-slot inputs: ```bash theme={null} stoffel run --client-input 0=42 --parties 5 --threshold 1 ``` ## Validate repository examples The repository examples are runnable programs under [`crates/stoffel-lang/examples/`](https://github.com/Stoffel-Labs/stoffel/tree/main/crates/stoffel-lang/examples). From the Stoffel repository root, compile the examples and run local-only examples through the VM with: ```bash theme={null} cd crates/stoffel-lang ./examples/validate_examples.sh ``` Compiled bytecode is written to `examples/dist/`. Use the [runnable examples guide](./examples) to choose examples by task. ## Common errors ### `secret` placement Use `secret` inside type annotations for share values: ```stoffel theme={null} def compute(x: secret int64) -> secret int64: var doubled: secret int64 = x * 2 return doubled ``` Do not use `secret` as a declaration modifier before `def` or `var`. The accepted form is `var x: secret int64 = ...`, not `secret var x = ...`. ### Secret control flow Do not branch on secret values. Reveal/open only the output you intend to disclose, or keep values as `Share` / `secret T` and send them to a client output path. ## See also * [StoffelLang Overview](./overview) * [Syntax and Examples](./syntax) * [Runnable Examples](./examples) * [Basic Usage](../getting-started/basic-usage)