/usr/bin/wasmtime

Wasmtime WebAssembly Runtime

Usage: wasmtime [OPTIONS] <WASM>...
       wasmtime <COMMAND>

Commands:
  run         Runs a WebAssembly module
  config      Controls Wasmtime configuration settings
  compile     Compiles a WebAssembly module
  explore     Explore the compilation of a WebAssembly module to native code
  serve       Serves requests from a wasi-http proxy component
  settings    Displays available Cranelift settings for a target
  wast        Runs a WebAssembly test script file
  completion  Generate shell completions for the `wasmtime` CLI
  objdump     Inspect `*.cwasm` files output from Wasmtime
  hot-blocks  Profile a Wasm module's execution and print the hottest basic blocks
  wizer       Wizer: the WebAssembly pre-initializer!
  help        Print this message or the help of the given subcommand(s)

Arguments:
  <WASM>...
          The WebAssembly module to run and arguments to pass to it.

          Arguments passed to the wasm module will be configured as WASI CLI arguments unless the
          `--invoke` CLI argument is passed in which case arguments will be interpreted as arguments
          to the function specified.

Options:
  -O, --optimize <KEY[=VAL[,..]]>
          Optimization and tuning related options for wasm performance, `-O help` to see all

  -C, --codegen <KEY[=VAL[,..]]>
          Codegen-related configuration options, `-C help` to see all

  -D, --debug <KEY[=VAL[,..]]>
          Debug-related configuration options, `-D help` to see all

  -W, --wasm <KEY[=VAL[,..]]>
          Options for configuring semantic execution of WebAssembly, `-W help` to see all

  -S, --wasi <KEY[=VAL[,..]]>
          Options for configuring WASI and its proposals, `-S help` to see all

  -R, --record <KEY[=VAL[,..]]>
          Options to enable and configure execution recording, `-R help` to see all.

          Generates a serialized trace of the Wasm module execution that captures all
          non-determinism observable by the module. This trace can subsequently be re-executed in a
          deterministic, embedding-agnostic manner (see the `wasmtime replay` command).

          Note: Minimal configuration options for deterministic Wasm semantics will be enforced
          during recording by default (NaN canonicalization, deterministic relaxed SIMD).

      --target <TARGET>
          The target triple; default is the host triple

      --config <FILE>
          Use the specified TOML configuration file. This TOML configuration file can provide same
          configuration options as the `--optimize`, `--codegen`, `--debug`, `--wasm`, `--wasi` CLI
          options, with a couple exceptions.

          Additional options specified on the command line will take precedent over options loaded
          from this TOML file.

      --allow-precompiled
          Allow executing precompiled WebAssembly modules as `*.cwasm` files.

          Note that this option is not safe to pass if the module being passed in is arbitrary user
          input. Only `wasmtime`-precompiled modules generated via the `wasmtime compile` command or
          equivalent should be passed as an argument with this option specified.

      --profile <STRATEGY>
          Profiling strategy (valid options are: perfmap, jitdump, vtune, guest)

          The perfmap, jitdump, and vtune profiling strategies integrate Wasmtime with external
          profilers such as `perf`. The guest profiling strategy enables in-process sampling and
          will write the captured profile to `wasmtime-guest-profile.json` by default which can be
          viewed at https://profiler.firefox.com/.

          The `guest` option can be additionally configured as:

          --profile=guest[,path[,interval]]

          where `path` is where to write the profile and `interval` is the duration between samples.
          When used with `--wasm-timeout` the timeout will be rounded up to the nearest multiple of
          this interval.

      --dir <HOST_DIR[::GUEST_DIR]>
          Grant access of a host directory to a guest.

          If specified as just `HOST_DIR` then the same directory name on the host is made available
          within the guest. If specified as `HOST::GUEST` then the `HOST` directory is opened and
          made available as the name `GUEST` in the guest.

      --env <NAME[=VAL]>
          Pass an environment variable to the program.

          The `--env FOO=BAR` form will set the environment variable named `FOO` to the value `BAR`
          for the guest program using WASI. The `--env FOO` form will set the environment variable
          named `FOO` to the same value it has in the calling process for the guest, or in other
          words it will cause the environment variable `FOO` to be inherited.

      --invoke <FUNCTION>
          The name of the function to run

      --preload <NAME=MODULE_PATH>
          Load the given WebAssembly module before the main module

      --argv0 <ARGV0>
          Override the value of `argv[0]`, typically the name of the executable of the application
          being run.

          This can be useful to pass in situations where a CLI tool is being executed that
          dispatches its functionality on the value of `argv[0]` without needing to rename the
          original wasm binary.

  -h, --help
          Print help (see a summary with '-h')

  -V, --version
          Print version

If a subcommand is not provided, the `run` subcommand will be used.

Usage examples:

Running a WebAssembly module with a start function:

  wasmtime example.wasm

Passing command line arguments to a WebAssembly module:

  wasmtime example.wasm arg1 arg2 arg3

Invoking a specific function (e.g. `add`) in a WebAssembly module:

  wasmtime --invoke add example.wasm 1 2