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# Workaround for bazel not supporting a shared exec and target configuration, even when they are
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# identical. https://github.com/bazelbuild/bazel/issues/14848
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# Derived from the tensorflow project (https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/tools/api/generator/api_gen.bzl)
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# See https://github.com/tensorflow/tensorflow/issues/60167 for discussion
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def _run_binary_target_impl(ctx):
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    tool = ctx.attr.tool[DefaultInfo].files_to_run.executable
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    flags = [ctx.expand_location(a) if "$(location" in a else a for a in ctx.attr.args]
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    cmd = " ".join([tool.path] + flags)
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    ctx.actions.run_shell(
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        inputs = ctx.files.srcs,
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        outputs = ctx.outputs.outs,
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        tools = [tool],
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        use_default_shell_env = True,
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        command = cmd,
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    )
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run_binary_target = rule(
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    implementation = _run_binary_target_impl,
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    attrs = {
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        "outs": attr.output_list(mandatory = True),
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        "srcs": attr.label_list(allow_files = True),
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        "args": attr.string_list(),
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        # Setting the configuration to "target" to avoid compiling code used in both this
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        # generator-like target and regular targets twice. For cross-compilation this would need to
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        # be set to "exec".
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        # Unfortunately bazel makes it very difficult to set the configuration at build time as
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        # macros are resolved before select() can be resolved based on the command line. This could
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        # alternatively be done by defining build targets and the rules used to declare them twice
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        # (once for exec and for target).
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        "tool": attr.label(
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            executable = True,
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            cfg = "target",
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            mandatory = True,
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        ),
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    },
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)