1 files changed, 147 insertions, 0 deletions
diff --git a/js/src/irregexp/import-irregexp.py b/js/src/irregexp/import-irregexp.py
new file mode 100755
index 0000000000..f136b33fbb
--- /dev/null
+++ b/js/src/irregexp/import-irregexp.py
@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This script handles all the mechanical steps of importing irregexp from v8:
+#
+# 1. Acquire the source: either from github, or optionally from a local copy of v8.
+# 2. Copy the contents of v8/src/regexp into js/src/irregexp/imported
+#    - Exclude files that we have chosen not to import.
+# 3. While doing so, update #includes:
+#    - Change "src/regexp/*" to "irregexp/imported/*".
+#    - Remove other v8-specific headers completely.
+# 4. Add '#include "irregexp/RegExpShim.h" in the necessary places.
+# 5. Update the IRREGEXP_VERSION file to include the correct git hash.
+#
+# Usage:
+#  cd path/to/js/src/irregexp
+#  ./import-irregexp.py --path path/to/v8/src/regexp
+#
+# Alternatively, without the --path argument, import-irregexp.py will
+# clone v8 from github into a temporary directory.
+#
+# After running this script, changes to the shim code may be necessary
+# to account for changes in upstream irregexp.
+
+import os
+import re
+import subprocess
+import sys
+from pathlib import Path
+
+
+def get_hash(path):
+    # Get the hash for the current git revision
+    cwd = os.getcwd()
+    os.chdir(path)
+    command = ["git", "rev-parse", "HEAD"]
+    result = subprocess.check_output(command, encoding="utf-8")
+    os.chdir(cwd)
+    return result.rstrip()
+
+
+def copy_and_update_includes(src_path, dst_path):
+    # List of header files that need to include the shim header
+    need_shim = [
+        "property-sequences.h",
+        "regexp-ast.h",
+        "regexp-bytecode-peephole.h",
+        "regexp-bytecodes.h",
+        "regexp-dotprinter.h",
+        "regexp-error.h",
+        "regexp.h",
+        "regexp-macro-assembler.h",
+        "regexp-stack.h",
+        "special-case.h",
+    ]
+
+    src = open(str(src_path), "r")
+    dst = open(str(dst_path), "w")
+
+    # 1. Rewrite includes of V8 regexp headers:
+    regexp_include = re.compile('#include "src/regexp')
+    regexp_include_new = '#include "irregexp/imported'
+
+    # 2. Remove includes of other V8 headers
+    other_include = re.compile('#include "src/')
+
+    # 3. If needed, add '#include "irregexp/RegExpShim.h"'.
+    #    Note: We get a little fancy to ensure that header files are
+    #    in alphabetic order. `need_to_add_shim` is true if we still
+    #    have to add the shim header in this file. `adding_shim_now`
+    #    is true if we have found a '#include "src/*' and we are just
+    #    waiting to find an empty line so that we can insert the shim
+    #    header in the right place.
+    need_to_add_shim = src_path.name in need_shim
+    adding_shim_now = False
+
+    for line in src:
+        if adding_shim_now:
+            if line == "\n":
+                dst.write('#include "irregexp/RegExpShim.h"\n')
+                need_to_add_shim = False
+                adding_shim_now = False
+
+        if regexp_include.search(line):
+            dst.write(re.sub(regexp_include, regexp_include_new, line))
+        elif other_include.search(line):
+            if need_to_add_shim:
+                adding_shim_now = True
+        else:
+            dst.write(line)
+
+
+def import_from(srcdir, dstdir):
+    excluded = [
+        "OWNERS",
+        "regexp.cc",
+        "regexp-utils.cc",
+        "regexp-utils.h",
+        "regexp-macro-assembler-arch.h",
+    ]
+
+    for file in srcdir.iterdir():
+        if file.is_dir():
+            continue
+        if str(file.name) in excluded:
+            continue
+        copy_and_update_includes(file, dstdir / "imported" / file.name)
+
+    # Update IRREGEXP_VERSION file
+    hash = get_hash(srcdir)
+    version_file = open(str(dstdir / "IRREGEXP_VERSION"), "w")
+    version_file.write("Imported using import-irregexp.py from:\n")
+    version_file.write("https://github.com/v8/v8/tree/%s/src/regexp\n" % hash)
+
+
+if __name__ == "__main__":
+    import argparse
+    import tempfile
+
+    # This script should be run from js/src/irregexp to work correctly.
+    current_path = Path(os.getcwd())
+    expected_path = "js/src/irregexp"
+    if not current_path.match(expected_path):
+        raise RuntimeError("%s must be run from %s" % (sys.argv[0], expected_path))
+
+    parser = argparse.ArgumentParser(description="Import irregexp from v8")
+    parser.add_argument("-p", "--path", help="path to v8/src/regexp")
+    args = parser.parse_args()
+
+    if args.path:
+        src_path = Path(args.path)
+
+        if not (src_path / "regexp.h").exists():
+            print("Usage:\n  import-irregexp.py --path <path/to/v8/src/regexp>")
+            sys.exit(1)
+        import_from(src_path, current_path)
+        sys.exit(0)
+
+    with tempfile.TemporaryDirectory() as tempdir:
+        v8_git = "https://github.com/v8/v8.git"
+        clone = "git clone --depth 1 %s %s" % (v8_git, tempdir)
+        os.system(clone)
+        src_path = Path(tempdir) / "src/regexp"
+        import_from(src_path, current_path)