zig-v8

Builds V8 from official source and provides C bindings and a Zig API. This would be used for embedding the V8 runtime into your Zig or C ABI compatible projects.

V8 is the JS/WASM runtime that powers Google Chrome and Microsoft Edge.

Project Status

Static libs are built and released with Github Actions.

Native	Cross Compile	Target	Demo Binary (shell.zig)*
✅		Linux x64	shell - 19 M
✅	✅	Windows x64	shell.exe - 14 M
✅		macOS x64	shell - 24 M
✅	✅	macOS arm64	shell - 21 M

* shell.zig is a JS repl and statically linked with v8. Compiled with -Doptimize=ReleaseSafe. The V8 dependency can be further reduced in size if you don't need all the features (eg. disable WASM runtime).

Toolchain	Fresh Build*	Cached Build*
gclient, full feature + v8 toolchain	1.5-2 hrs	with sccache: 10-20min
minimal feature + v8 toolchain	40-50 min	with sccache: 5-10min
minimal feature + zig c++ toolchain		with zig caching:

* Time is measured on standard Github instances.

System Requirements

• Zig compiler (0.11.0). You can get that here.
• Python 3 (2.7 seems to work as well)
• For native macOS builds:
  • XCode (You won't need this when using zig's c++ toolchain!)
    if you come across this error:
    xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
    run sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

Build

By default UseGclient=false in build.zig. This will pull the minimum sources and deps needed to build v8 and reduce build times.

If you want to include everything, set UseGclient=true. Build times can be quite long using gclient but afterwards rerunning "zig build" should be incremental. You can also use sccache for better incremental build times.

# Clone the repo.
git clone https://github.com/fubark/zig-v8.git
cd zig-v8

# Pull prebuilt GN/Ninja. If UseGclient=true, it also pulls depot_tools.
zig build get-tools

# Pull v8 source
zig build get-v8

# Build, resulting static library should be at:
# v8-build/{target}/{debug/release}/ninja/obj/zig/libc_v8.a
# On windows, use msvc: zig build -Doptimize=ReleaseSafe -Dtarget=x86_64-windows-msvc
zig build -Doptimize=ReleaseSafe

Demo

# shell.zig is a simple JS repl.
# Assumes you've already built v8.
zig build run -Dpath="src/shell.zig" -Doptimize=ReleaseSafe

# If you built v8 using the zig toolchain, you'll need to add the flag here as well.
zig build run -Dpath="src/shell.zig" -Doptimize=ReleaseSafe -Dzig-toolchain

Cross Compiling

With Zig's toolchain, we can build V8 from libstdc++ that's bundled with zig and cross compile to foreign targets/cpus! Simply amazing. Eventually, this will also replace the default V8 toolchain for native builds after further testing.

Linux x64 (Host) to MacOS arm64 (Target)

# Assumes you've fetched tools and v8 sources. See above build steps.
# Resulting static lib will be at:
# v8-build/aarch64-macos/release/ninja/obj/zig/libc_v8.a
zig build -Doptimize=ReleaseSafe -Dtarget=aarch64-macos-gnu -Dzig-toolchain

Cross compile to Windows with gnu (mingw64)

Zig comes with mingw64 source and headers so you'll be able to target Windows without MSVC.

zig build -Doptimize=ReleaseSafe -Dtarget=x86_64-windows-gnu -Dzig-toolchain

Usage

See src/shell.zig or test/test.zig on how to use the library with the Zig API as well as build.zig (fn linkV8) on how to link with the built V8 static library.

Contributing

The C bindings is incomplete but it should be relatively easy to add more as we need them.

C API naming convention should closely follow the V8 C++ API.

Troubleshooting

If you get an error saying that it can't find any of the following:

pkg-config
glib-2.0
gmodule-2.0
gobject-2.0
gthread-2.0

You'll need to run the following command before continuing:

sudo apt install -y pkg-config libglib2.0-dev

Or your distro's equivalent