llvm-capstone/llvm-libgcc/generate_version_script.py
Tobias Hieta f98ee40f4b
[NFC][Py Reformat] Reformat python files in the rest of the dirs
This is an ongoing series of commits that are reformatting our
Python code. This catches the last of the python files to
reformat. Since they where so few I bunched them together.

Reformatting is done with `black`.

If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.

If you run into any problems, post to discourse about it and
we will try to help.

RFC Thread below:

https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style

Reviewed By: jhenderson, #libc, Mordante, sivachandra

Differential Revision: https://reviews.llvm.org/D150784
2023-05-25 11:17:05 +02:00

130 lines
4.2 KiB
Python
Executable File

#!/usr/bin/env python3
# Generates a version script for an architecture so that it can be incorporated
# into gcc_s.ver.
from collections import defaultdict
from itertools import chain
import argparse, subprocess, sys, os
def split_suffix(symbol):
"""
Splits a symbol such as `__gttf2@GCC_3.0` into a triple representing its
function name (__gttf2), version name (GCC_3.0), and version number (300).
The version number acts as a priority. Since earlier versions are more
accessible and are likely to be used more, the lower the number is, the higher
its priortiy. A symbol that has a '@@' instead of '@' has been designated by
the linker as the default symbol, and is awarded a priority of -1.
"""
if "@" not in symbol:
return None
data = [i for i in filter(lambda s: s, symbol.split("@"))]
_, version = data[-1].split("_")
version = version.replace(".", "")
priority = -1 if "@@" in symbol else int(version + "0" * (3 - len(version)))
return data[0], data[1], priority
def invert_mapping(symbol_map):
"""Transforms a map from Key->Value to Value->Key."""
store = defaultdict(list)
for symbol, (version, _) in symbol_map.items():
store[version].append(symbol)
result = []
for k, v in store.items():
v.sort()
result.append((k, v))
result.sort(key=lambda x: x[0])
return result
def intersection(llvm, gcc):
"""
Finds the intersection between the symbols extracted from compiler-rt.a/libunwind.a
and libgcc_s.so.1.
"""
common_symbols = {}
for i in gcc:
suffix_triple = split_suffix(i)
if not suffix_triple:
continue
symbol, version_name, version_number = suffix_triple
if symbol in llvm:
if symbol not in common_symbols:
common_symbols[symbol] = (version_name, version_number)
continue
if version_number < common_symbols[symbol][1]:
common_symbols[symbol] = (version_name, version_number)
return invert_mapping(common_symbols)
def find_function_names(path):
"""
Runs readelf on a binary and reduces to only defined functions. Equivalent to
`llvm-readelf --wide ${path} | grep 'FUNC' | grep -v 'UND' | awk '{print $8}'`.
"""
result = subprocess.run(args=["llvm-readelf", "-su", path], capture_output=True)
if result.returncode != 0:
print(result.stderr.decode("utf-8"), file=sys.stderr)
sys.exit(1)
stdout = result.stdout.decode("utf-8")
stdout = filter(lambda x: "FUNC" in x and "UND" not in x, stdout.split("\n"))
stdout = chain(map(lambda x: filter(None, x), (i.split(" ") for i in stdout)))
return [list(i)[7] for i in stdout]
def to_file(versioned_symbols):
path = f"{os.path.dirname(os.path.realpath(__file__))}/new-gcc_s-symbols"
with open(path, "w") as f:
f.write(
"Do not check this version script in: you should instead work "
"out which symbols are missing in `lib/gcc_s.ver` and then "
"integrate them into `lib/gcc_s.ver`. For more information, "
"please see `doc/LLVMLibgcc.rst`.\n"
)
for version, symbols in versioned_symbols:
f.write(f"{version} {{\n")
for i in symbols:
f.write(f" {i};\n")
f.write("};\n\n")
def read_args():
parser = argparse.ArgumentParser()
parser.add_argument(
"--compiler_rt",
type=str,
help="Path to `libclang_rt.builtins-${ARCH}.a`.",
required=True,
)
parser.add_argument(
"--libunwind", type=str, help="Path to `libunwind.a`.", required=True
)
parser.add_argument(
"--libgcc_s",
type=str,
help="Path to `libgcc_s.so.1`. Note that unlike the other two arguments, this is a dynamic library.",
required=True,
)
return parser.parse_args()
def main():
args = read_args()
llvm = find_function_names(args.compiler_rt) + find_function_names(args.libunwind)
gcc = find_function_names(args.libgcc_s)
versioned_symbols = intersection(llvm, gcc)
# TODO(cjdb): work out a way to integrate new symbols in with the existing
# ones
to_file(versioned_symbols)
if __name__ == "__main__":
main()