SSVM is a high performance, extensible, and hardware optimized WebAssembly Virtual Machine for cloud, AI, and blockchain applications.

starsStars 589
forksForks 30
watchersWatchers 589
current-versionCurrent version 0.7.2
total-releasesTotal releases 21
open_issues_countOpen issues 2
dateFirst release 2019-11-29
dateLatest release 2020-12-17
updateLast update 2020-12-23


SSVM is a high performance and enterprise-ready WebAssembly (WASM) Virtual Machine for cloud, AI, and Blockchain applications. Its use cases include the following.

Getting Started

Get Source Code

$ git clone
$ cd SSVM
$ git checkout 0.7.1

Prepare the environment

Use our docker image

Our docker image use ubuntu 20.04 as the base.

$ docker pull secondstate/ssvm

Or setup the environment manually

# Tools and libraries
$ sudo apt install -y \
	software-properties-common \
	cmake \

# And you will need to install llvm for ssvm-aot tools
$ sudo apt install -y \
	llvm-dev \

# SSVM supports both clang++ and g++ compilers
# You can choose one of them for building this project
$ sudo apt install -y gcc g++
$ sudo apt install -y clang

Build SSVM

SSVM provides various tools for enabling different runtime environments for optimal performance. After the build is finished, you can find there are several ssvm related tools:

  1. ssvm is for general wasm runtime. Interpreter mode.
  2. ssvm-qitc is for AI application, supporting ONNC runtime for AI model in ONNX format.
  3. ssvm-aot is for general wasm runtime. AOT compilation mode.
    • ssvmc compiles a general wasm runtime to so file.
    • ssvmr execute a general wasm runtime or so file in WASI environment.
    • To disable building the ahead of time compilation runtime, you can set the CMake option SSVM_DISABLE_AOT_RUNTIME to OFF.
# After pulling our ssvm docker image
$ docker run -it --rm \
    -v <path/to/your/ssvm/source/folder>:/root/ssvm \
(docker)$ cd /root/ssvm
(docker)$ mkdir -p build && cd build
(docker)$ cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTS=ON .. && make -j

SSVM requires libLLVM-10 and GLIBCXX_3.4.26 or after. If users want to build and run ssvm interpreter tool without these dependencies, they can set the CMake option SSVM_DISABLE_AOT_RUNTIME and STATIC_BUILD to ON.


Run built-in tests

The following built-in tests are only available when the build flag BUILD_TESTS sets to ON.

Users can use these tests to verify the correctness of SSVM binaries.

$ cd <path/to/ssvm/build_folder>
$ ctest

Run ssvm (SSVM with general wasm runtime)

To run SSVM with general wasm runtime, users will need to provide the following parameters:

  1. (Optional) Reactor mode: use --reactor to enable reactor mode.
    • SSVM will execute the function which name should be given in ARG[0].
    • If there's exported function which names _initialize, the function will be executed with the empty parameter at first.
  2. (Optional) Binding directories into WASI virtual filesystem.
    • Each directory can be specified as --dir host_path:guest_path.
  3. (Optional) Environ variables.
    • Each variable can be specified as --env NAME=VALUE.
  4. Wasm file(/path/to/wasm/file).
  5. (Optional) Arguments.
    • In reactor mode, the first argument will be the function name, and the arguments after ARG[0] will be parameters of wasm function ARG[0].
    • In command mode, the arguments will be parameters of function _start.

Example: Fibonacci

# cd <path/to/ssvm/build_folder>
$ cd tools/ssvm
# ./ssvm [--reactor] [--dir PREOPEN_DIRS ...] [--env ENVS ...] [--] WASM_FILE [ARG ...]
$ ./ssvm --reactor examples/fibonacci.wasm fib 10

When wrong number of parameter given, the following error message is printed.

$ ./ssvm --reactor examples/fibonacci.wasm fib 10 10
2020-08-21 06:30:37,304 ERROR [default] execution failed: function signature mismatch, Code: 0x83
2020-08-21 06:30:37,304 ERROR [default]     Mismatched function type. Expected: params{i32} returns{i32} , Got: params{i32 , i32} returns{i32}
2020-08-21 06:30:37,304 ERROR [default]     When executing function name: "fib"

When calling unknown exported function, the following error message is printed.

$ ./ssvm --reactor examples/fibonacci.wasm fib2 10
2020-08-21 06:30:56,981 ERROR [default] ssvm runtime failed: wasm function not found, Code: 0x04
2020-08-21 06:30:56,981 ERROR [default]     When executing function name: "fib2"

Example: Factorial

# ./ssvm [--reactor] [--dir PREOPEN_DIRS ...] [--env ENVS ...] [--] WASM_FILE [ARG ...]
$ ./ssvm --reactor examples/factorial.wasm fac 5

Related tools



This project provides a shared library that can initialize and execute by the EVMC interface.

SSVM nodejs addon

SSVM-napi provides support for accessing SSVM as a Node.js addon.

It allows Node.js applications to call WebAssembly functions written in Rust or other high-performance languages.

Why do you want to run WebAssembly on the server-side?

The SSVM addon could interact with the wasm files generated by the ssvmup compiler tool.


The Second State DevChain features a powerful and easy-to-use virtual machine that can quickly get you started with the smart contract and DApp development.

SSVM-evmc is integrated into our DevChain. Click here to learn how to run an ewasm smart contract on a real blockchain.

Customized Host Functions

Design document shows how to register customized host functions into SSVM and execute with wasm files.