WebAssembly Micro Runtime

Build WAMR | Build AOT Compiler | Embed WAMR | Export Native API | Build WASM Apps | Samples

A Bytecode Alliance project

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (WASM) runtime with small footprint, high performance and highly configurable features for applications cross from embedded, IoT, edge to Trusted Execution Environment (TEE), smart contract, cloud native and so on. It includes a few parts as below:

• The "iwasm" VM core to run WASM applications, supporting interpreter mode, AOT mode (Ahead-of-Time compilation) and JIT mode (Just-in-Time compilation)

• The "wamrc" AOT compiler to compile WASM file into AOT file for best performance and smaller runtime footprint, which is run by "iwasm" VM Core

• The application framework and the supporting APIs for the WASM applications

• The dynamic management of the WASM applications

Getting started

• Build iwasm VM core on Linux, SGX, MacOS and Windows, and Build wamrc AOT compiler
• Embed WAMR into host applications
• Register native APIs for WASM applications
• Build WASM applications
• Port WAMR to a new platform
• Benchmarks and Samples

iwasm VM core

Key features

• Full compliant to the W3C WASM MVP
• Small runtime binary size (~85K for interpreter and ~50K for AOT) and low memory usage
• Near to native speed by AOT and JIT
• Self-implemented AOT module loader to enable AOT working on Linux, Windows, MacOS, Android, SGX and MCU systems
• Choices of WASM application libc support: the built-in libc subset for the embedded environment or WASI for the standard libc
• The simple C APIs to embed WAMR into host environment, see how to integrate WAMR and the API list
• The mechanism to export native APIs to WASM applications, see how to register native APIs
• Multiple modules as dependencies, ref to document and sample
• Multi-thread, pthread APIs and thread management, ref to document and sample
• Linux SGX (Intel Software Guard Extension) support, ref to document
• Source debugging support, ref to document
• WAMR-IDE (Experimental) to develop WebAssembly applications with build, run and debug support, ref to document
• XIP (Execution In Place) support, ref to document
• Berkeley/Posix Socket support, ref to document and sample

WASM post-MVP features

• wasm-c-api, ref to document and sample
• 128-bit SIMD, ref to samples/workload
• Reference Types, ref to document and sample
• Non-trapping float-to-int conversions
• Sign-extension operators, Bulk memory operations
• Multi-value, Tail-call, Shared memory

Supported architectures and platforms

The iwasm supports the following architectures:

• X86-64, X86-32
• ARM, THUMB (ARMV7 Cortex-M7 and Cortex-A15 are tested)
• AArch64 (Cortex-A57 and Cortex-A53 are tested)
• RISCV64, RISCV32 (RISC-V LP64 and RISC-V LP64D are tested)
• XTENSA, MIPS, ARC

The following platforms are supported, click each link below for how to build iwasm on that platform. Refer to WAMR porting guide for how to port WAMR to a new platform.

• Linux, Linux SGX (Intel Software Guard Extension), MacOS, Android, Windows, Windows (MinGW)
• Zephyr, AliOS-Things, VxWorks, NuttX, RT-Thread, ESP-IDF

Build iwasm VM core (mini product)

WAMR supports building the iwasm VM core only (no app framework) to the mini product. The WAMR mini product takes the WASM application file name or AOT file name as input and then executes it. For the detailed procedure, please see build WAMR VM core and build and run WASM application. Also we can click the link of each platform above to see how to build iwasm on it.

Build wamrc AOT compiler

Both wasm binary file and AOT file are supported by iwasm. The wamrc AOT compiler is to compile wasm binary file to AOT file which can also be run by iwasm. Execute following commands to build wamrc compiler for Linux:

cd wamr-compiler
./build_llvm.sh (or "./build_llvm_xtensa.sh" to support xtensa target)
mkdir build && cd build
cmake .. (or "cmake .. -DWAMR_BUILD_PLATFORM=darwin" for MacOS)
make
# wamrc is generated under current directory

For Windows：

cd wamr-compiler
python build_llvm.py
mkdir build && cd build
cmake ..
cmake --build . --config Release
# wamrc.exe is generated under .\Release directory

Performance and Footprint

• Performance and footprint data: checkout here for the performance and footprint data
• Memory usage tunning: checkout here for the memory model and how to tune the memory usage
• Memory usage profiling: checkout here for how to profile the memory usage
• Benchmarks: checkout these links for how to run the benchmarks: PolyBench, CoreMark, Sightglass, JetStream2

User cases

WAMR is widely used in a lot areas, here are some cases:

• Hyperledger Private Data Objects
• Inclavare Containers
• Fassm
• Waft
• Envoy Proxy
• Apache Teaclave

Application framework

By using the iwasm VM core, we are flexible to build different application frameworks for the specific domains, although it would take quite some effort.

The WAMR has offered a comprehensive framework for programming WASM applications for device and IoT usages. The framework supports running multiple applications, that are based on the event driven programming model. Here are the supporting API sets by the WAMR application framework library :

• Timer, Inter-app communication (request/response and pub/sub), Sensor, Connectivity and data transmission, 2D graphic UI

Browse the folder core/app-framework for how to extend the application framework.

Remote application management

The WAMR application manager supports remote application management from the host environment or the cloud through any physical communications such as TCP, UPD, UART, BLE, etc. Its modular design makes it able to support application management for different managed runtimes.

The tool host_tool communicates to the WAMR app manager for installing/uninstalling the WASM applications on companion chip from the host system. And the IoT App Store Demo shows the conception of remotely managing the device applications from the cloud.

WAMR SDK

Usually there are two tasks for integrating the WAMR into a particular project:

• Select what WAMR components (vmcore, libc, app-mgr, app-framework components) to be integrated, and get the associated source files added into the project building configuration
• Generate the APP SDK for developing the WASM apps on the selected libc and framework components

The WAMR SDK tools is helpful to finish the two tasks quickly. It supports menu configuration for selecting WAMR components and builds the WAMR to a SDK package that includes runtime SDK and APP SDK. The runtime SDK is used for building the native application and the APP SDK should be shipped to WASM application developers.

Samples

The WAMR samples integrate the iwasm VM core, application manager and selected application framework components.

• basic: Demonstrating how to use runtime exposed API's to call WASM functions, how to register native functions and call them, and how to call WASM function from native function.
• simple: The runtime is integrated with most of the WAMR APP libraries, and a few WASM applications are provided for testing the WAMR APP API set. It uses built-in libc and executes apps in interpreter mode by default.
• littlevgl: Demonstrating the graphic user interface application usage on WAMR. The whole LVGL 2D user graphic library and the UI application are built into WASM application. It uses WASI libc and executes apps in AOT mode by default.
• gui: Move the LVGL library into the runtime and define a WASM application interface by wrapping the littlevgl API. It uses WASI libc and executes apps in interpreter mode by default.
• multi-thread: Demonstrating how to run wasm application which creates multiple threads to execute wasm functions concurrently, and uses mutex/cond by calling pthread related API's.
• spawn-thread: Demonstrating how to execute wasm functions of the same wasm application concurrently, in threads created by host embedder or runtime, but not the wasm application itself.
• multi-module: Demonstrating the multiple modules as dependencies feature which implements the load-time dynamic linking.
• ref-types: Demonstrating how to call wasm functions with argument of externref type introduced by reference types proposal.
• wasm-c-api: Demonstrating how to run some samples from wasm-c-api proposal and showing the supported API's.
• socket-api: Demonstrating how to run wasm tcp server and tcp client applications, and how they communicate with each other.
• workload: Demonstrating how to build and run some complex workloads, e.g. tensorflow-lite, XNNPACK, wasm-av1, meshoptimizer and bwa.

Project Technical Steering Committee

The WAMR PTSC Charter governs the operations of the project TSC. The current TSC members:

• lum1n0us - Liang He， liang.he@intel.com
• no1wudi Qi Huang, huangqi3@xiaomi.com
• qinxk-inter - Xiaokang Qin， xiaokang.qxk@antgroup.com
• wei-tang - Wei Tang， tangwei.tang@antgroup.com
• wenyongh - Wenyong Huang， wenyong.huang@intel.com
• xujuntwt95329 - Jun Xu， Jun1.Xu@intel.com
• xwang98 - Xin Wang， xin.wang@intel.com (chair)

License

WAMR uses the same license as LLVM: the Apache 2.0 license with the LLVM exception. See the LICENSE file for details. This license allows you to freely use, modify, distribute and sell your own products based on WAMR. Any contributions you make will be under the same license.

More resources

Check out the Wiki documents for more resources:

• Community news and events
• Roadmap
• WAMR TSC meetings
• Technical documents