platforms/experimental/platform_data/defs.bzl

86 lines
2.3 KiB
Python

"""
The platform_data rule can be used to change the target platform of a target,
and then depend on that elsewhere in the build tree. For example:
load("@platforms//experimental/platform_data:defs.bzl", "platform_data")
cc_binary(name = "foo")
platform_data(
name = "foo_embedded",
target = ":foo",
platform = "//my/new:platform",
)
py_binary(
name = "flasher",
srcs = ...,
data = [
":foo_embedded",
],
)
Regardless of what platform the top-level :flasher binary is built for,
the :foo_embedded target will be built for //my/new:platform.
Note that if you depend on :foo_embedded it's not exactly the same as depending on :foo, since it won't forward all the same providers. In the future, we can extend this to add some common providers as needed."""
def _target_platform_transition_impl(attr):
return {
"//command_line_option:platforms": str(attr.platform),
}
_target_platform_transition = transition(
implementation = _target_platform_transition_impl,
inputs = [],
outputs = [
"//command_line_option:platforms",
],
)
def _platform_data_impl(ctx):
target = ctx.attr.target
default_info = target[DefaultInfo]
files = default_info.files
original_executable = default_info.files_to_run.executable
runfiles = default_info.default_runfiles
new_executable = ctx.actions.declare_file(ctx.attr.name)
ctx.actions.symlink(
output = new_executable,
target_file = original_executable,
is_executable = True,
)
files = depset(direct = [new_executable], transitive = [files])
runfiles = runfiles.merge(ctx.runfiles([new_executable]))
return [
DefaultInfo(
files = files,
runfiles = runfiles,
executable = new_executable,
)
]
platform_data = rule(
implementation = _platform_data_impl,
attrs = {
"target": attr.label(
allow_files = False,
executable = True,
mandatory = True,
cfg = _target_platform_transition,
),
"platform": attr.label(
mandatory = True,
),
"_allowlist_function_transition": attr.label(
default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
),
},
executable = True,
)