This migrates the bazel integration to the new Bazel dependency system
"bzlmod". bzlmod is becoming mandatory this year (see second sentence
here: https://bazel.build/external/migration).
This is a backwards incompatible migration, directly removing the old
WORKSPACE based approach. Users will have to change how they depend on
bzlmod, however I assume pretty much every user will be happy about it,
because they are forced to use bzlmod anyway or add extra flags to
continue to build with newer Bazel versions. Given that users normally
depend on specific git commits in the old system, they won't be hit with
this until they decide to upgrade emsdk.
The basic principle here is simple: I took everything that WORKSPACE did
and searched an alternative in bzlmod. Some interesting bits:
- We have less worries about multiple versions and people depending on
emscripten multiple times in different ways. This is resolved by the new
system: Bazel first iterates through the MODULE.bazel files recursively,
then finds the minimum version needed for each module and then executes
the module extensions that define repos exactly once at that version. So
no more ifs needed to detect multiple inclusions.
- A bunch of nodejs stuff moves to MODULE.bazel, because that is how the
nodejs module works now. As their module extension gets executed only
once you need to declare everything that you could need before that in
the MODULE.bazel file. A side effect of that is that we have to make a
fake repository when emscripten doesn't have an arm64 binary for linux,
because we can't actually figure that out in MODULE.bazel, so we have to
declare that it always exists and then create one in all cases.
There is a bunch of autoformatter changes in here as well, I could try
to revert them if you prefer.
Closes#1509
This is a working solution for generating a separate Emscripten cache.
Note that this requires an additional entry in the workspace as follows:
```starlark
load("@emsdk//:emscripten_cache.bzl", emsdk_emscripten_cache = "emscripten_cache")
emsdk_emscripten_cache()
```
When used like this, the default Emscripten cache will be used. However,
if the entry is as follows:
```starlark
load("@emsdk//:emscripten_cache.bzl", emsdk_emscripten_cache = "emscripten_cache")
emsdk_emscripten_cache(flags = ["--lto"])
```
Then embuilder will be called to build all system libraries and ports
(i.e., the `ALL` option to embuilder) with the LTO option enabled. This
can take awhile, so I have also made possible to specify which libraries
you want to build explicitly:
```starlark
load("@emsdk//:emscripten_cache.bzl", emsdk_emscripten_cache = "emscripten_cache")
emsdk_emscripten_cache(
flags = ["--lto"],
libraries = [
"crtbegin",
"libprintf_long_double-debug",
"libstubs-debug",
"libnoexit",
"libc-debug",
"libdlmalloc",
"libcompiler_rt",
"libc++-noexcept",
"libc++abi-debug-noexcept",
"libsockets"
]
)
```
Resolves#807, resolves#971, resolves#1099, resolves#1362, resolves
#1401
This script is (IMO) more readable, but the real reason for this change is that
it raises an error message when the binary package fails to download. (The shell
script silently generated a bogus hash instead, because the shell's `set -e`
builtin does not affect commands executing inside a $() context.
It seemed just as easy to rewrite the script in Python as to fix that.
This change also updates some outdated filename references.
* Makes provided bazel rules look up @emsdk workspace instead of local workspace
* Uses system-specific emscripten binaries instead of defaulting to linux
* Provides macros for loading emsdk dependencies (nodejs and emscripten binaries)
* Unhardcodes paths in bazel rules and .sh wrappers
* `update_bazel_workspace.sh` now updates `revisions.bzl`
* `emscripten_deps()` can be fed with specific emscripten version
* Adds external usage test
Addresses #650 and #696
