04944ddff6
* Add linux/arm64 support to bazel rules * Make linux arm64 sha optional and PR feedback Not all releases have linux shas. Use getattr to default to no sha if none was present. This way non linux arm64 builds should not fail. * Update linux arm64 sha for 3.1.33 This is the latest arm64 release according to #1204. There do not seem to be a any releases between .21 and .33.
Bazel Emscripten toolchain
Setup Instructions
In WORKSPACE file, put:
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
http_archive(
name = "emsdk",
sha256 = "d55e3c73fc4f8d1fecb7aabe548de86bdb55080fe6b12ce593d63b8bade54567",
strip_prefix = "emsdk-3891e7b04bf8cbb3bc62758e9c575ae096a9a518/bazel",
url = "https://github.com/emscripten-core/emsdk/archive/3891e7b04bf8cbb3bc62758e9c575ae096a9a518.tar.gz",
)
load("@emsdk//:deps.bzl", emsdk_deps = "deps")
emsdk_deps()
load("@emsdk//:emscripten_deps.bzl", emsdk_emscripten_deps = "emscripten_deps")
emsdk_emscripten_deps(emscripten_version = "2.0.31")
load("@emsdk//:toolchains.bzl", "register_emscripten_toolchains")
register_emscripten_toolchains()
The SHA1 hash in the above strip_prefix and url parameters correspond to the git revision of
emsdk 2.0.31. To get access to
newer versions, you'll need to update those. To make use of older versions, change the
parameter of emsdk_emscripten_deps(). Supported versions are listed in revisions.bzl
Building
Put the following line into your .bazelrc:
build --incompatible_enable_cc_toolchain_resolution
Then write a new rule wrapping your cc_binary.
load("@rules_cc//cc:defs.bzl", "cc_binary")
load("@emsdk//emscripten_toolchain:wasm_rules.bzl", "wasm_cc_binary")
cc_binary(
name = "hello-world",
srcs = ["hello-world.cc"],
)
wasm_cc_binary(
name = "hello-world-wasm",
cc_target = ":hello-world",
)
Now you can run bazel build :hello-world-wasm. The result of this build will
be the individual files produced by emscripten. Note that some of these files
may be empty. This is because bazel has no concept of optional outputs for
rules.
wasm_cc_binary uses transition to use emscripten toolchain on cc_target
and all of its dependencies, and does not require amending .bazelrc. This
is the preferred way, since it also unpacks the resulting tarball.
See test_external/ for an example using embind.