v8 147.3.0

Rust bindings to V8
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

#!/usr/bin/env python3

# Copyright 2022 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import contextlib
import os
import subprocess
import sys

# Set up path to be able to import action_helpers.
sys.path.append(
    os.path.join(os.path.dirname(os.path.abspath(__file__)), os.pardir,
                 os.pardir, os.pardir, 'build'))
import action_helpers

from filter_clang_args import filter_clang_args


def PrependVersionLine(filepath):
  # Prepending a version line accomplishes two goals:
  # * P1: Incrementing the version forces reindexing of the generated code
  #   by Chromium Code Search (e.g. needed to verify the fix from
  #   https://crbug.com/466084840)
  # * P2: It leaves a breadcrumb about `//build/rust` to help readers of
  #   the generated code figure out where/how to control how Chromium
  #   invokes `bindgen`.
  VERSION = "2025-12-22"
  with open(filepath, 'r', encoding='utf-8') as f:
    original_content = f.read()
  with open(filepath, 'w', encoding='utf-8') as f:
    tool_description = f"`//build/rust/gni_impl/run_bindgen.py` v{VERSION}"
    f.write(f"/* @generated by {tool_description} */\n")
    f.write(original_content)


def main():
  parser = argparse.ArgumentParser("run_bindgen.py")
  parser.add_argument("--bindgen-exe", help="Path to bindgen", required=True),
  parser.add_argument("--rustfmt-exe", help="Path to rustfmt", required=True),
  parser.add_argument("--header",
                      help="C header file to generate bindings for",
                      required=True)
  parser.add_argument("--depfile",
                      help="depfile to output with header dependencies")
  parser.add_argument("--output", help="output .rs bindings", required=True)
  parser.add_argument(
      "--wrap-static-fns",
      help="output source file for `static` and `static inline` functions")
  parser.add_argument("--ld-library-path",
                      help="LD_LIBRARY_PATH (or DYLD_LIBRARY_PATH on Mac) to "
                      "set")
  parser.add_argument("--libclang-path",
                      help="Path to the libclang shared libray.")
  parser.add_argument("-I", "--include", help="include path", action="append")
  parser.add_argument("--bindgen-flags",
                      help="flags to pass to bindgen",
                      nargs="*")
  parser.add_argument(
      "clangargs",
      metavar="CLANGARGS",
      help="arguments to pass to libclang (see "
      "https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#method.clang_args)",
      nargs="*")
  args = parser.parse_args()

  # Abort if `TARGET` exists in the environment. Cargo sets `TARGET` when
  # running build scripts and bindgen will try to be helpful by using that value
  # if it's set. In practice we've seen a case where someone had the value set
  # in their build environment with no intention of it reaching bindgen, leading
  # to a hard-to-debug build error.
  #if 'TARGET' in os.environ:
  #  sys.exit('ERROR: saw TARGET in environment, remove to avoid bindgen'
  #           ' failures')

  with contextlib.ExitStack() as stack:
    # Args passed to the actual bindgen cli
    genargs = []
    genargs.append('--no-layout-tests')
    if args.bindgen_flags is not None:
      for flag in args.bindgen_flags:
        genargs.append("--" + flag)

    # TODO(danakj): We need to point bindgen to
    # //third_party/rust-toolchain/bin/rustfmt.
    genargs.append('--no-rustfmt-bindings')
    genargs += ['--rust-target', 'nightly']

    if args.depfile:
      depfile = stack.enter_context(action_helpers.atomic_output(args.depfile))
      genargs.append('--depfile')
      genargs.append(depfile.name)
    # Ideally we would use action_helpers.atomic_output for the output file, but
    # this would put the wrong name in the depfile.
    genargs.append('--output')
    genargs.append(args.output)

    # The GN rules know what path to find the system headers in, and we want to
    # use the headers we specify, instead of non-hermetic headers from elsewhere
    # in the system.
    genargs.append('--no-include-path-detection')

    if args.wrap_static_fns:
      wrap_static_fns = stack.enter_context(
          action_helpers.atomic_output(args.wrap_static_fns))
      genargs.append('--experimental')
      genargs.append('--wrap-static-fns')
      genargs.append('--wrap-static-fns-path')
      genargs.append(wrap_static_fns.name)
    genargs.append(args.header)
    genargs.append('--')
    genargs.extend(filter_clang_args(args.clangargs))
    env = os.environ
    if args.ld_library_path:
      if sys.platform == 'darwin':
        env["DYLD_LIBRARY_PATH"] = args.ld_library_path
      else:
        env["LD_LIBRARY_PATH"] = args.ld_library_path
    if args.libclang_path:
      env["LIBCLANG_PATH"] = args.libclang_path
    try:
      subprocess.check_call([args.bindgen_exe, *genargs], env=env)

      fmtargs = [
          args.output,
          "--config=normalize_doc_attributes=true",
      ]
      subprocess.check_call([args.rustfmt_exe, *fmtargs])

      PrependVersionLine(args.output)
    except:
      # Make sure we don't emit anything if bindgen failed. The other files use
      # action_helpers for this.
      try:
        os.remove(args.output)
      except FileNotFoundError:
        pass
      raise


if __name__ == '__main__':
  main()