| #!/usr/bin/env python3 |
| |
| # Copyright 2021 The Chromium Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| import argparse |
| import pathlib |
| import subprocess |
| import os |
| import sys |
| import re |
| |
| # Set up path to be able to import build_utils |
| sys.path.append( |
| os.path.join(os.path.dirname(os.path.abspath(__file__)), os.pardir, |
| os.pardir, 'build', 'android', 'gyp')) |
| from util import build_utils |
| |
| # This script wraps rustc for (currently) three reasons: |
| # * To work around some ldflags escaping performed by ninja/gn |
| # * To remove dependencies on some environment variables from the .d file. |
| # * To enable use of .rsp files. |
| # |
| # LDFLAGS ESCAPING |
| # |
| # This script performs a simple function to work around some of the |
| # parameter escaping performed by ninja/gn. |
| # |
| # rustc invocations are given access to {{rustflags}} and {{ldflags}}. |
| # We want to pass {{ldflags}} into rustc, using -Clink-args="{{ldflags}}". |
| # Unfortunately, ninja assumes that each item in {{ldflags}} is an |
| # independent command-line argument and will have escaped them appropriately |
| # for use on a bare command line, instead of in a string. |
| # |
| # This script converts such {{ldflags}} into individual -Clink-arg=X |
| # arguments to rustc. |
| # |
| # RUSTENV dependency stripping |
| # |
| # When Rust code depends on an environment variable at build-time |
| # (using the env! macro), rustc spots that and adds it to the .d file. |
| # Ninja then parses that .d file and determines that the environment |
| # dependency means that the target always needs to be rebuilt. |
| # |
| # That's all correct, but _we_ know that some of these environment |
| # variables (typically, all of them) are set by .gn files which ninja |
| # tracks independently. So we remove them from the .d file. |
| # |
| # RSP files: |
| # |
| # We want to put the ninja/gn variables {{rustdeps}} and {{externs}} |
| # in an RSP file. Unfortunately, they are space-separated variables |
| # but Rust requires a newline-separated input. This script duly makes |
| # the adjustment. This works around a gn issue: |
| # TODO(https://bugs.chromium.org/p/gn/issues/detail?id=249): fix this |
| # |
| # Usage: |
| # rustc_wrapper.py --rustc <path to rustc> --depfile <path to .d file> |
| # -- <normal rustc args> LDFLAGS {{ldflags}} RUSTENV {{rustenv}} |
| # The LDFLAGS token is discarded, and everything after that is converted |
| # to being a series of -Clink-arg=X arguments, until or unless RUSTENV |
| # is encountered, after which those are interpreted as environment |
| # variables to pass to rustc (and which will be removed from the .d file). |
| # |
| # Both LDFLAGS and RUSTENV **MUST** be specified, in that order, even if |
| # the list following them is empty. |
| # |
| # TODO(https://github.com/rust-lang/rust/issues/73632): avoid using rustc |
| # for linking in the first place. Most of our binaries are linked using |
| # clang directly, but there are some types of Rust build product which |
| # must currently be created by rustc (e.g. unit test executables). As |
| # part of support for using non-rustc linkers, we should arrange to extract |
| # such functionality from rustc so that we can make all types of binary |
| # using our clang toolchain. That will remove the need for most of this |
| # script. |
| |
| |
| def main(): |
| parser = argparse.ArgumentParser() |
| parser.add_argument('--rustc', required=True, type=pathlib.Path) |
| parser.add_argument('--depfile', type=pathlib.Path) |
| parser.add_argument('--rsp', type=pathlib.Path) |
| parser.add_argument('args', metavar='ARG', nargs='+') |
| |
| args = parser.parse_args() |
| |
| remaining_args = args.args |
| |
| ldflags_separator = remaining_args.index("LDFLAGS") |
| rustenv_separator = remaining_args.index("RUSTENV", ldflags_separator) |
| rustc_args = remaining_args[:ldflags_separator] |
| ldflags = remaining_args[ldflags_separator + 1:rustenv_separator] |
| rustenv = remaining_args[rustenv_separator + 1:] |
| |
| rustc_args.extend(["-Clink-arg=%s" % arg for arg in ldflags]) |
| |
| # Workaround for https://bugs.chromium.org/p/gn/issues/detail?id=249 |
| if args.rsp: |
| with open(args.rsp) as rspfile: |
| rsp_args = [l.rstrip() for l in rspfile.read().split(' ') if l.rstrip()] |
| with open(args.rsp, 'w') as rspfile: |
| rspfile.write("\n".join(rsp_args)) |
| rustc_args.append(f'@{args.rsp}') |
| |
| env = os.environ.copy() |
| fixed_env_vars = [] |
| for item in rustenv: |
| (k, v) = item.split("=", 1) |
| env[k] = v |
| fixed_env_vars.append(k) |
| |
| r = subprocess.run([args.rustc, *rustc_args], env=env, check=False) |
| if r.returncode != 0: |
| sys.exit(r.returncode) |
| |
| # Now edit the depfile produced |
| if args.depfile is not None: |
| env_dep_re = re.compile("# env-dep:(.*)=.*") |
| replacement_lines = [] |
| dirty = False |
| with open(args.depfile, encoding="utf-8") as d: |
| for line in d: |
| m = env_dep_re.match(line) |
| if m and m.group(1) in fixed_env_vars: |
| dirty = True # skip this line |
| else: |
| replacement_lines.append(line) |
| if dirty: # we made a change, let's write out the file |
| with build_utils.AtomicOutput(args.depfile) as output: |
| output.write("\n".join(replacement_lines).encode("utf-8")) |
| |
| |
| if __name__ == '__main__': |
| sys.exit(main()) |