1#!/usr/bin/env python
2#
3# Copyright (C) 2018 The Android Open Source Project
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#      http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17# This script looks through compiled object file (stored human readable text),
18# and looks for the compile-time constants (added through custom "asm" block).
19#   For example:  .ascii  ">>OBJECT_ALIGNMENT_MASK $7 $0<<"
20#
21# It will transform each such line to #define which is usabe in assembly code.
22#   For example:  #define OBJECT_ALIGNMENT_MASK 0x7
23#
24# Usage: make_header.py out/soong/.intermediates/.../asm_defines.o
25#
26
27import argparse
28import re
29import sys
30
31def convert(input):
32  """Find all defines in the compiler generated assembly and convert them to #define pragmas"""
33
34  asm_define_re = re.compile(r'">>(\w+) (?:\$|#)?([-0-9]+) (?:\$|#)?(0|1)<<"')
35  asm_defines = asm_define_re.findall(input)
36  if not asm_defines:
37    raise RuntimeError("Failed to find any asm defines in the input")
38
39  # Convert the found constants to #define pragmas.
40  # In case the C++ compiler decides to reorder the AsmDefinesFor_${name} functions,
41  # we don't want the order of the .h file to change from one compilation to another.
42  # Sorting ensures deterministic order of the #defines.
43  output = []
44  for name, value, negative_value in sorted(asm_defines):
45    value = int(value)
46    if value < 0 and negative_value == "0":
47      # Overflow - uint64_t constant was pretty printed as negative value.
48      value += 2 ** 64  # Python will use arbitrary precision arithmetic.
49    output.append("#define {0} {1:#x}".format(name, value))
50  return "\n".join(output)
51
52if __name__ == "__main__":
53  parser = argparse.ArgumentParser()
54  parser.add_argument('input', help="Object file as text")
55  args = parser.parse_args()
56  print(convert(open(args.input, "r").read()))
57