1 files changed, 57 insertions, 0 deletions
diff --git a/tools/cpp-define-generator/make_header.py b/tools/cpp-define-generator/make_header.py
new file mode 100755
index 0000000000..95ef7bc56d
--- /dev/null
+++ b/tools/cpp-define-generator/make_header.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script looks through compiled object file (stored human readable text),
+# and looks for the compile-time constants (added through custom "asm" block).
+#   For example:  .ascii  ">>OBJECT_ALIGNMENT_MASK $7 $0<<"
+#
+# It will transform each such line to #define which is usabe in assembly code.
+#   For example:  #define OBJECT_ALIGNMENT_MASK 0x7
+#
+# Usage: make_header.py out/soong/.intermediates/.../asm_defines.o
+#
+
+import argparse
+import re
+import sys
+
+def convert(input):
+  """Find all defines in the compiler generated assembly and convert them to #define pragmas"""
+
+  asm_define_re = re.compile(r'">>(\w+) (?:\$|#)([-0-9]+) (?:\$|#)(0|1)<<"')
+  asm_defines = asm_define_re.findall(input)
+  if not asm_defines:
+    raise RuntimeError("Failed to find any asm defines in the input")
+
+  # Convert the found constants to #define pragmas.
+  # In case the C++ compiler decides to reorder the AsmDefinesFor_${name} functions,
+  # we don't want the order of the .h file to change from one compilation to another.
+  # Sorting ensures deterministic order of the #defines.
+  output = []
+  for name, value, negative_value in sorted(asm_defines):
+    value = int(value)
+    if value < 0 and negative_value == "0":
+      # Overflow - uint64_t constant was pretty printed as negative value.
+      value += 2 ** 64  # Python will use arbitrary precision arithmetic.
+    output.append("#define {0} {1:#x}".format(name, value))
+    output.append("#define {0} {1:#x}".format(name.upper(), value))
+  return "\n".join(output)
+
+if __name__ == "__main__":
+  parser = argparse.ArgumentParser()
+  parser.add_argument('input', help="Object file as text")
+  args = parser.parse_args()
+  print(convert(open(args.input, "r").read()))