build/rust/run_rs_bindings_from_cc.py

   1 #!/usr/bin/env python3
   2
   3 # Copyright 2022 The Chromium Authors
   4 # Use of this source code is governed by a BSD-style license that can be
   5 # found in the LICENSE file.
   6
   7 import argparse
   8 import json
   9 import os
  10 import subprocess
  11 import sys
  12
  13 THIS_DIR = os.path.dirname(os.path.abspath(__file__))
  14 CHROMIUM_SRC_DIR = os.path.relpath(os.path.join(THIS_DIR, os.pardir, os.pardir))
  15 sys.path.append(THIS_DIR)
  16 from run_bindgen import filter_clang_args
  17
  18 RUST_TOOLCHAIN_DIR = os.path.join(CHROMIUM_SRC_DIR, "third_party",
  19                                   "rust-toolchain")
  20 RUSTFMT_EXE_PATH = os.path.join(RUST_TOOLCHAIN_DIR, "bin", "rustfmt")
  21 RUSTFMT_CONFIG_PATH = os.path.join(CHROMIUM_SRC_DIR, ".rustfmt.toml")
  22 RS_BINDINGS_FROM_CC_EXE_PATH = os.path.join(RUST_TOOLCHAIN_DIR, "bin",
  23                                             "rs_bindings_from_cc")
  24
  25
  26 def format_cmdline(args):
  27   def quote_arg(x):
  28     if ' ' not in x: return x
  29     x = x.replace('"', '\\"')
  30     return f"\"{x}\""
  31
  32   return " ".join([quote_arg(x) for x in args])
  33
  34
  35 def main():
  36   parser = argparse.ArgumentParser()
  37   parser.add_argument("--targets_and_args_from_gn",
  38                       metavar="FILE",
  39                       help="File parsed into --targets_and_args Crubit arg",
  40                       required=True),
  41   parser.add_argument("--public_headers",
  42                       metavar="FILE",
  43                       help="Passed through to Crubit",
  44                       required=True),
  45   parser.add_argument("--rs_out",
  46                       metavar="FILE",
  47                       help="Passed through to Crubit",
  48                       required=True),
  49   parser.add_argument("--cc_out",
  50                       metavar="FILE",
  51                       help="Passed through to Crubit",
  52                       required=True),
  53   parser.add_argument("clang_args",
  54                       metavar="CLANGARGS",
  55                       help="Arguments to forward to clang libraries",
  56                       nargs=argparse.REMAINDER)
  57   args = parser.parse_args()
  58
  59   # Output paths
  60   generator_args = []
  61   generator_args.append("--rs_out={0}".format(os.path.relpath(args.rs_out)))
  62   generator_args.append("--cc_out={0}".format(os.path.relpath(args.cc_out)))
  63   if "CRUBIT_DEBUG" in os.environ:
  64     generator_args.append("--ir_out={0}".format(
  65         os.path.relpath(args.rs_out).replace(".rs", ".ir")))
  66
  67   # Public headers.
  68   generator_args.append("--public_headers={0}".format(",".join(
  69       [os.path.relpath(hdr) for hdr in args.public_headers.split(",")])))
  70
  71   # Targets to headers map.
  72   with open(args.targets_and_args_from_gn, "r") as f:
  73     targets_and_args = json.load(f)
  74   for entry in targets_and_args:
  75     entry["f"] = ["supported"]
  76     hdrs = entry["h"]
  77     for i in range(len(hdrs)):
  78       hdrs[i] = os.path.relpath(hdrs[i])
  79   generator_args.append("--targets_and_args={0}".format(
  80       json.dumps(targets_and_args)))
  81
  82   # All Crubit invocations in Chromium share the following cmdline args.
  83   generator_args.append(f"--rustfmt_exe_path={RUSTFMT_EXE_PATH}")
  84   generator_args.append(f"--rustfmt_config_path={RUSTFMT_CONFIG_PATH}")
  85   generator_args.append(
  86       "--crubit_support_path=third_party/crubit/src/rs_bindings_from_cc/support"
  87   )
  88
  89   # Long cmdlines may not work - work around that by using Abseil's `--flagfile`
  90   # https://abseil.io/docs/python/guides/flags#a-note-about---flagfile
  91   #
  92   # Note that `clang_args` are not written to the flag file, because Abseil's
  93   # flag parsing code is only aware of `ABSL_FLAG`-declared flags and doesn't
  94   # know about Clang args (e.g. `-W...` or `-I...`).
  95   params_file_path = os.path.relpath(args.rs_out).replace(".rs", ".params")
  96   with open(params_file_path, "w") as f:
  97     for line in generator_args:
  98       print(line, file=f)
  99
 100   # Clang arguments.
 101   #
 102   # The call to `filter_clang_args` is needed to avoid the following error:
 103   # error: unable to find plugin 'find-bad-constructs'
 104   clang_args = []
 105   clang_args.extend(filter_clang_args(args.clang_args))
 106   # TODO(crbug.com/1329611): This warning needs to be suppressed, because
 107   # otherwise Crubit/Clang complains as follows:
 108   #     error: .../third_party/rust-toolchain/bin/rs_bindings_from_cc:
 109   #     'linker' input unused [-Werror,-Wunused-command-line-argument]
 110   # Maybe `build/rust/rs_bindings_from_cc.gni` gives too much in `args`?  But
 111   # then `{{cflags}}` seems perfectly reasonable...
 112   clang_args += ["-Wno-unused-command-line-argument"]
 113
 114   # Print a copy&pastable final cmdline when asked for debugging help.
 115   cmdline = [RS_BINDINGS_FROM_CC_EXE_PATH, f"--flagfile={params_file_path}"]
 116   cmdline.extend(clang_args)
 117   if "CRUBIT_DEBUG" in os.environ:
 118     pretty_cmdline = format_cmdline(cmdline)
 119     print(f"CRUBIT_DEBUG: CMDLINE: {pretty_cmdline}", file=sys.stderr)
 120
 121   # TODO(crbug.com/1329611): run_bindgen.py removes the outputs when the tool
 122   # fails.  Maybe we need to do something similar here?  OTOH in most failure
 123   # modes Crubit will fail *before* generating its outputs...
 124   return subprocess.run(cmdline).returncode
 125
 126
 127 if __name__ == '__main__':
 128   sys.exit(main())