com_stevenengelhardt_rules_emscripten

Bazel rules for building C/C++ code into Javascript using the Emscripten toolset. Supports builds on Linux, OS X, and Windows.

Build Status

Table of Contents

• Build Status
• Quick Start Guide
• Repository Rules
  • emscripten_setup
    • Attributes
• Build Rules
  • emcc_binary
    • Attributes
  • emcc_module
    • Attributes

Quick Start Guide

Add the following stanza to WORKSPACE:

http_archive(
    name = "com_stevenengelhardt_rules_emscripten",
    sha256 = "d4e2f81085f27579609411c97989bb586f7b9ae0c555345a0617c96b7d1aa47e",
    urls = ["https://github.com/sengelha/rules_emscripten/releases/download/v1.5.2/rules_emscripten-1.5.2.zip"],
)

load("@com_stevenengelhardt_rules_emscripten//emscripten:deps.bzl", "emscripten_rules_dependencies", "emscripten_setup")
emscripten_rules_dependencies()
emscripten_setup()

Add the following stanza to BUILD, adjusting as needed:

load("@com_stevenengelhardt_rules_emscripten//emscripten:def.bzl", "emcc_binary")

emcc_binary(
    name = "hello_world",
    srcs = ["main.cpp"],
)

For more examples, see examples.

Repository Rules

emscripten_setup

Setup up com_stevenengelhardt_rules_emscripten, including registering appropriate toolchains.

emscripten_setup(version)

Attributes

Attribute Name	Type	Required?	Description
version	String	optional	The version of Emscripten to use. Set to host to use the emscripten SDK installed on the host machine. Defaults to the latest supported Emscripten SDK.

Build Rules

emcc_binary

Compiles a set of C/C++ files into a JavaScript "binary" (a .js and a .wasm file) and allows it be executed via bazel run.

Attributes

Attribute Name	Type	Required?	Description
name	Name	required	A unique name for this rule.
srcs	List of files	required	A list of source files required to compile the binary.
emit_wasm	Boolean	Optional	Whether to emit a WASM file as part of the build. Default = True.
emit_memory_init_file	Boolean	Optional	Whether to emit a memory init file. Only applies if emit_wasm = False. Default = True.
configuration	String	optional	The build configuration for the target (dbg, opt, or fastbuild). If not specified, uses the global -c option value.

emcc_module

Compiles a set of C/C++ files into a JavaScript module (a .js and a .wasm file).

Attributes

Attribute Name	Type	Required?	Description
name	Name	required	A unique name for this rule.
srcs	List of files	required	A list of source files required to compile the module.
modularize	Boolean	optional	Whether to output a JS module, as in the emcc -s MODULARIZE=1 option. Default = True.
emit_wasm	Boolean	Optional	Whether to emit a WASM file as part of the build. Default = True.
emit_memory_init_file	Boolean	Optional	Whether to emit a memory init file. Only applies if emit_wasm = False. Default = True.
pre_js	File	optional	A JavaScript file to prepend to the output using emcc's --pre-js option.
post_js	File	optional	A JavaScript file to append to the output using emcc's --post-js option.
extern_pre_js	File	optional	A JavaScript file to prepend to the output using emcc's --extern-pre-js option.
extern_post_js	File	optional	A JavaScript file to append to the output using emcc's --extern-post-js option.
linkopts	List of strings	optional	Additional flags to add to emcc at link time
configuration	String	optional	The build configuration for the target (dbg, opt, or fastbuild). If not specified, uses the global -c option value.