122 lines
3.5 KiB
Python
122 lines
3.5 KiB
Python
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"""Copyright (C) 2022 The Android Open Source Project
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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load("@bazel_skylib//lib:paths.bzl", "paths")
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"""Build rule for converting `.l` or `.ll` to C or C++ sources with Flex.
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Uses flex (and m4 under the hood) to convert .l and .ll source files into
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.c and .cc files. Does not support .lex or .lpp extensions
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Examples
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--------
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This is a simple example.
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```
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genlex(
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name = "html_lex",
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src = "html.l",
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)
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```
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This example uses some options for flex.
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```
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genlex(
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name = "rules_l",
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src = "rules.l",
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lexopts = ["-d", "-v"],
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)
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```
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"""
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def _genlex_impl(ctx):
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"""Implementation for genlex rule."""
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# TODO(b/190006308): When fixed, l and ll sources can coexist. Remove this.
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exts = [f.extension for f in ctx.files.srcs]
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contains_l = False
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contains_ll = False
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for ext in exts:
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if ext == "l":
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contains_l = True
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if ext == "ll":
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contains_ll = True
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if contains_l and contains_ll:
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fail(
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"srcs contains both .l and .ll files. Please use separate targets.",
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)
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outputs = []
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for src_file in ctx.files.srcs:
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args = ctx.actions.args()
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output_filename = ""
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src_ext = src_file.extension
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split_filename = src_file.basename.partition(".")
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filename_without_ext = split_filename[0]
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if src_ext == "l":
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output_filename = paths.replace_extension(filename_without_ext, ".c")
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elif src_ext == "ll":
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output_filename = paths.replace_extension(filename_without_ext, ".cc")
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output_file = ctx.actions.declare_file(output_filename)
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outputs.append(output_file)
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args.add("-o", output_file.path)
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args.add_all(ctx.attr.lexopts)
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args.add(src_file)
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ctx.actions.run(
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executable = ctx.executable._flex,
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env = {
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"M4": ctx.executable._m4.path,
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},
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arguments = [args],
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inputs = [src_file],
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tools = [ctx.executable._m4],
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outputs = [output_file],
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mnemonic = "Flex",
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progress_message = "Generating %s from %s" % (
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output_filename,
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src_file.short_path,
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),
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)
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return [DefaultInfo(files = depset(outputs))]
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genlex = rule(
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implementation = _genlex_impl,
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doc = "Generate C/C++-language sources from a lex file using Flex.",
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attrs = {
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"srcs": attr.label_list(
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mandatory = True,
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allow_files = [".l", ".ll"],
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doc = "The lex source file for this rule",
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),
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"lexopts": attr.string_list(
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doc = "A list of options to be added to the flex command line.",
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),
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"_flex": attr.label(
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default = "//prebuilts/build-tools:flex",
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executable = True,
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cfg = "exec",
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),
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"_m4": attr.label(
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default = "//prebuilts/build-tools:m4",
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executable = True,
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cfg = "exec",
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),
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},
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)
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