blob: aa222ceaa42a70fa1eae98eb6ce32ae5b023ebd1 [file] [log] [blame]
#!/usr/bin/env python3.8
# Copyright 2020 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Script to generate runtimes.json for Clang toolchain
This script invokes Clang with different flags to discover the corresponding
runtime paths. The script also ensures that every runtime is stripped and if
not strips it into the .build-id directory, and optionally also generates a
breakpad file. Finally, it prints runtimes.json consumed by the build.
# TODO(phosek): consider rewriting this script in Go reusing the existing logic
# in //tools/debug to populate .build-id directory and generate breakpad.
import argparse
import json
import os
import re
import shutil
import subprocess
import sys
ELF_MAGIC = b"\x7fELF"
TARGETS = ["x86_64-unknown-fuchsia", "aarch64-unknown-fuchsia"]
"x86_64-unknown-fuchsia": "x64",
"aarch64-unknown-fuchsia": "arm64",
# TODO(phosek): use `clang --target=... -print-multi-lib` instead of hardcoding
# these once it supports all variants.
CFLAGS = [[], ["-fsanitize=address"], ["-fsanitize=undefined"]]
LDFLAGS = [[], ["-static-libstdc++"]]
def trace_link(clang_dir, target, sysroot, cflags, ldflags):
cmd = [
os.path.join(clang_dir, "bin", "clang++"),
"--target=%s" % target,
"--sysroot=%s" % sysroot,
if cflags:
if ldflags:
p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
outs, errs = p.communicate(input=b"int main() {}")
return outs.decode().splitlines()
def read_soname_and_build_id(readelf, filename):
p = subprocess.Popen(
[readelf, "-Wnd", filename], stdout=subprocess.PIPE, env={"LC_ALL": "C"}
outs, _ = p.communicate()
if p.returncode != 0:
raise Exception("failed to read notes")
match ="Library soname: \[([a-zA-Z0-9.+_-]+)\]", outs.decode())
soname = if match else None
match ="Build ID: ([a-zA-Z0-9_-]+)", outs.decode())
if not match:
raise Exception("build ID missing")
build_id =
return soname, build_id
def generate_entry(filename, clang_dir, build_id_dir, dump_syms):
entry = {"dist": os.path.relpath(filename, clang_dir)}
soname, build_id = read_soname_and_build_id(
os.path.join(clang_dir, "bin", "llvm-readelf"), filename
if soname:
entry["soname"] = soname
if not build_id_dir:
return entry
dist_file = build_id_dir + "/%s/%s" % (build_id[0:2], build_id[2:])
debug_file = dist_file + ".debug"
os.makedirs(os.path.dirname(debug_file), exist_ok=True)
if not os.path.exists(debug_file):
try:, debug_file)
except OSError, e:
if e.errno == errno.EXDEV:
shutil.copyfile(filename, debug_file)
raise e
if not os.path.exists(dist_file):
os.path.join(clang_dir, "bin", "llvm-objcopy"),
entry["dist"] = dist_file
entry["debug"] = debug_file
if not dump_syms:
return entry
breakpad_file = build_id_dir + ".sym"
if not os.path.exists(breakpad_file):
with open(breakpad_file, "w") as f:
soname = soname or os.path.basename(filename)
[dump_syms, "-r", "-n", soname, "-o", "Fuchsia", debug_file], stdout=f,
entry["breakpad"] = breakpad_file
return entry
def main():
parser = argparse.ArgumentParser()
parser.add_argument("--clang-toolchain", required=True, help="path to Clang")
parser.add_argument("--fuchsia-sdk", required=True, help="path to Fuchsia SDK")
parser.add_argument("--build-id-dir", help="path .build-id directory")
parser.add_argument("--dump-syms", help="path to Breakpad dump_syms utility")
args = parser.parse_args()
clang_dir = os.path.abspath(args.clang_toolchain)
build_id_dir = os.path.abspath(args.build_id_dir) if args.build_id_dir else None
if build_id_dir and build_id_dir.startswith(clang_dir):
build_id_dir = os.path.relpath(build_id_dir, clang_dir)
runtimes = []
for target in TARGETS:
arch = TRIPLE_TO_TARGET[target]
sysroot = os.path.join(args.fuchsia_sdk, "arch", arch, "sysroot")
for cflags in CFLAGS:
for ldflags in LDFLAGS:
runtime = []
for lib in trace_link(clang_dir, target, sysroot, cflags, ldflags):
lib_path = os.path.abspath(lib)
if not os.path.isfile(lib_path):
with open(lib_path, "rb") as f:
magic =
if magic != ELF_MAGIC:
if not lib_path.startswith(clang_dir):
lib_path, clang_dir, build_id_dir, args.dump_syms
"cflags": cflags,
"ldflags": ldflags,
"runtime": runtime,
"target": [target],
json.dump(runtimes, sys.stdout, indent=2, sort_keys=True)
return 0
if __name__ == "__main__":