[libc] Add a TableGen based header generator.

Summary:
* The Python header generator has been removed.
* Docs giving a highlevel overview of the header gen scheme have been
  added.

Reviewers: phosek, abrachet

Subscribers: mgorny, MaskRay, tschuett, libc-commits

Tags: #libc-project

Differential Revision: https://reviews.llvm.org/D70197

1 files changed, 0 insertions, 188 deletions

diff --git a/libc/utils/build_scripts/gen_hdr.py b/libc/utils/build_scripts/gen_hdr.py
deleted file mode 100755
index 54ee0063a02..00000000000
--- a/libc/utils/build_scripts/gen_hdr.py
+++ /dev/null
@@ -1,188 +0,0 @@
-#! /usr/bin/python
-#===---------------- Script to generate header files ----------------------===#
-#
-# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-# See https:#llvm.org/LICENSE.txt for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-#
-#===-----------------------------------------------------------------------===#
-#
-# This script takes a .h.def file and generates a .h header file.
-# See docs/header_generation.md for more information.
-#
-#===-----------------------------------------------------------------------===#
-
-import argparse
-import contextlib
-import os
-import sys
-
-COMMAND_PREFIX = "%%"
-COMMENT_PREFIX = "<!>"
-
-BEGIN_COMMAND = "begin"
-COMMENT_COMMAND = "comment"
-INCLUDE_FILE_COMMAND = "include_file"
-
-
-class _Location(object):
-    def __init__(self, filename, line_number):
-        self.filename = filename
-        self.line_number = line_number
-
-    def __str__(self):
-        return "%s:%s" % (self.filename, self.line_number)
-
-
-@contextlib.contextmanager
-def output_stream_manager(filename):
-    if filename is None:
-        try:
-            yield sys.stdout
-        finally:
-            pass
-    else:
-        output_stream = open(filename, "w")
-        try:
-            yield output_stream
-        finally:
-            output_stream.close()
-
-
-def _parse_command(loc, line):
-    open_paren = line.find("(")
-    if open_paren < 0 or line[-1] != ")":
-        return _fatal_error(loc, "Incorrect header generation command syntax.")
-    command_name = line[len(COMMAND_PREFIX):open_paren]
-    args = line[open_paren + 1:-1].split(",")
-    args = [a.strip() for a in args]
-    if len(args) == 1 and not args[0]:
-        # There are no args, so we will make the args list an empty list.
-        args = []
-    return command_name.strip(), args
-
-
-def _is_named_arg(token):
-    if token.startswith("${") and token.endswith("}"):
-        return True
-    else:
-        return False
-
-
-def _get_arg_name(token):
-    return token[2:-1]
-
-
-def _fatal_error(loc, msg):
-    sys.exit("ERROR:%s: %s" % (loc, msg))
-
-
-def _is_begin_command(line):
-    if line.startswith(COMMAND_PREFIX + BEGIN_COMMAND):
-        return True
-
-
-def include_file_command(out_stream, loc, args, values):
-    if len(args) != 1:
-        _fatal_error(loc, "`%%include_file` command takes exactly one "
-                     "argument. %d given." % len(args))
-    include_file_path = args[0]
-    if _is_named_arg(include_file_path):
-        arg_name = _get_arg_name(include_file_path)
-        include_file_path = values.get(arg_name)
-        if not include_file_path:
-            _fatal_error(
-                loc,
-                "No value specified for argument '%s'." % arg_name)
-        if not os.path.exists(include_file_path):
-            _fatal_error(
-                loc,
-                "Include file %s not found." % include_file_path)
-    with open(include_file_path, "r") as include_file:
-        begin = False
-        for line in include_file.readlines():
-            line = line.strip()
-            if _is_begin_command(line):
-                # Parse the command to make sure there are no errors.
-                command_name, args = _parse_command(loc, line)
-                if args:
-                    _fatal_error(loc, "Begin command does not take any args.")
-                begin = True
-                # Skip the line on which %%begin() is listed.
-                continue
-            if begin:
-                out_stream.write(line + "\n")
-
-
-def begin_command(out_stream, loc, args, values):
-    # "begin" command can only occur in a file included with %%include_file
-    # command. It is not a replacement command. Hence, we just fail with
-    # a fatal error.
-    _fatal_error(loc, "Begin command cannot be listed in an input file.")
-
-
-# Mapping from a command name to its implementation function.
-REPLACEMENT_COMMANDS = {
-    INCLUDE_FILE_COMMAND: include_file_command,
-    BEGIN_COMMAND: begin_command,
-}
-
-
-def apply_replacement_command(out_stream, loc, line, values):
-    if not line.startswith(COMMAND_PREFIX):
-        # This line is not a replacement command.
-        return line
-    command_name, args = _parse_command(loc, line)
-    command = REPLACEMENT_COMMANDS.get(command_name.strip())
-    if not command:
-        _fatal_error(loc, "Unknown replacement command `%`", command_name)
-    command(out_stream, loc, args, values)
-
-
-def parse_options():
-    parser = argparse.ArgumentParser(
-        description="Script to generate header files from .def files.")
-    parser.add_argument("def_file", metavar="DEF_FILE",
-                        help="Path to the .def file.")
-    parser.add_argument("--args", "-P", nargs= "*", default=[],
-                        help="NAME=VALUE pairs for command arguments in the "
-                             "input .def file.")
-    # The output file argument is optional. If not specified, the generated
-    # header file content will be written to stdout.
-    parser.add_argument("--out-file", "-o",
-                        help="Path to the generated header file. Defaults to "
-                             "stdout")
-    opts = parser.parse_args()
-    if not all(["=" in arg for arg in opts.args]):
-        # We want all args to be specified in the form "name=value".
-        _fatal_error(
-            __file__ + ":" + "[command line]",
-            "Command arguments should be listed in the form NAME=VALUE")
-    return opts
-
-
-def main():
-    opts = parse_options()
-    arg_values = {}
-    for name_value_pair in opts.args:
-        name, value = name_value_pair.split("=")
-        arg_values[name] = value
-    with open(opts.def_file, "r") as def_file:
-        loc = _Location(opts.def_file, 0)
-        with output_stream_manager(opts.out_file) as out_stream:
-            for line in def_file:
-                loc.line_number += 1
-                line = line.strip()
-                if line.startswith(COMMAND_PREFIX):
-                    replacement_text = apply_replacement_command(
-                        out_stream, loc, line, arg_values)
-                    out_stream.write("\n")
-                elif line.startswith(COMMENT_PREFIX):
-                    # Ignore comment line
-                    continue
-                else:
-                    out_stream.write(line + "\n")
-
-
-if __name__ == "__main__":
-    main()