id | title |
---|---|
building-and-running |
Building and Running Hermes |
This document describes how to build and run Hermes as a standalone compiler and VM. To use Hermes in the context of a React Native app, see the React Native documentation.
Hermes is a C++11 project. clang, gcc, and Visual C++ are supported. Hermes also requires cmake, git, ICU, Python, and zip. It builds with CMake and ninja.
The Hermes REPL will also use libreadline, if available.
To install dependencies on Ubuntu:
apt install cmake git ninja-build libicu-dev python zip libreadline-dev
On Arch Linux:
pacman -S cmake git ninja icu python zip readline
On Mac via Homebrew:
brew install cmake git ninja
Hermes will place its build files in the current directory by default.
You can also give explicit source and build directories, use --help
on the build scripts to see how.
Create a base directory to work in, e.g. ~/workspace
, and cd into it.
(Tip: avoid naming it hermes
, as hermes
will be one of several subdirectories in the workspace).
After cd
ing, follow the steps below to generate the Hermes build system:
git clone https://github.com/facebook/hermes.git
hermes/utils/build/configure.py
The build system has now been generated in the build
directory. To perform the build:
cd build && ninja
The above instructions create an unoptimized debug build. The --distribute
flag will enable a release build, in the build_release
directory. Example:
hermes/utils/build/configure.py --distribute
cd build_release && ninja
The Windows build depends on which particular combination of GitBash/Cygwin/WSL and Visual Studio is used.
git -c core.autocrlf=false clone https://github.com/facebook/hermes.git
hermes/utils/build/configure.py --build-system='Visual Studio 16 2019' --cmake-flags='-A x64' --distribute
cd build_release && MSBuild.exe ALL_BUILD.vcxproj /p:Configuration=Release
The primary binary is the hermes
tool, which will be found at build/bin/hermes
. This tool compiles JavaScript to Hermes bytecode. It can also execute JavaScript, from source or bytecode or be used as a REPL.
hermes test.js
hermes -emit-binary -out test.hbc test.js
hermes test.hbc
To run the Hermes test suite:
ninja check-hermes
In addition to hermes
, the following tools will be built:
hdb
: JavaScript command line debuggerhbcdump
: Hermes bytecode disassemblerhermesc
: Standalone Hermes compiler. This can compile JavaScript to Hermes bytecode, but does not support executing it.hvm
: Standalone Hermes VM. This can execute Hermes bytecode, but does not support compiling it.