llvm-project

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#!/usr/bin/env python3
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"""Replaces absolute line numbers in lit-tests with relative line numbers.
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Writing line numbers like 152 in 'RUN: or CHECK:' makes tests hard to maintain:
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inserting lines in the middle of the test means updating all the line numbers.
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Encoding them relative to the current line helps, and tools support it:
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    Lit will substitute %(line+2) with the actual line number
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    FileCheck supports [[@LINE+2]]
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This tool takes a regex which captures a line number, and a list of test files.
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It searches for line numbers in the files and replaces them with a relative
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line number reference.
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"""
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USAGE = """Example usage:
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    find -type f clang/test/CodeCompletion | grep -v /Inputs/ | \\
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    xargs relative_lines.py --dry-run --verbose --near=100 \\
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    --pattern='-code-completion-at[ =]%s:(\d+)' \\
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    --pattern='requires fix-it: {(\d+):\d+-(\d+):\d+}'
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"""
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import argparse
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import re
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import sys
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def b(x):
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    return bytes(x, encoding="utf-8")
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parser = argparse.ArgumentParser(
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    prog="relative_lines",
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    description=__doc__,
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    epilog=USAGE,
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    formatter_class=argparse.RawTextHelpFormatter,
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)
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parser.add_argument(
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    "--near", type=int, default=20, help="maximum line distance to make relative"
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)
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parser.add_argument(
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    "--partial",
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    action="store_true",
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    default=False,
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    help="apply replacements to files even if others failed",
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)
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parser.add_argument(
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    "--pattern",
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    default=[],
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    action="append",
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    type=lambda x: re.compile(b(x)),
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    help="regex to match, with line numbers captured in ().",
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)
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parser.add_argument(
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    "--verbose", action="store_true", default=False, help="print matches applied"
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)
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parser.add_argument(
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    "--dry-run",
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    action="store_true",
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    default=False,
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    help="don't apply replacements. Best with --verbose.",
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)
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parser.add_argument("files", nargs="+")
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args = parser.parse_args()
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for file in args.files:
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    try:
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        contents = open(file, "rb").read()
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    except UnicodeDecodeError as e:
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        print(f"{file}: not valid UTF-8 - {e}", file=sys.stderr)
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    failures = 0
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    def line_number(offset):
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        return 1 + contents[:offset].count(b"\n")
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    def replace_one(capture, line, offset):
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        """Text to replace a capture group, e.g. 42 => %(line+1)"""
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        try:
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            target = int(capture)
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        except ValueError:
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            print(f"{file}:{line}: matched non-number '{capture}'", file=sys.stderr)
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            return capture
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        if args.near > 0 and abs(target - line) > args.near:
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            print(
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                f"{file}:{line}: target line {target} is farther than {args.near}",
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                file=sys.stderr,
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            )
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            return capture
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        if target > line:
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            delta = "+" + str(target - line)
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        elif target < line:
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            delta = "-" + str(line - target)
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        else:
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            delta = ""
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        prefix = contents[:offset].rsplit(b"\n")[-1]
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        is_lit = b"RUN" in prefix or b"DEFINE" in prefix
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        text = ("%(line{0})" if is_lit else "[[@LINE{0}]]").format(delta)
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        if args.verbose:
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            print(f"{file}:{line}: {0} ==> {text}")
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        return b(text)
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    def replace_match(m):
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        """Text to replace a whole match, e.g. --at=42:3 => --at=%(line+2):3"""
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        line = 1 + contents[: m.start()].count(b"\n")
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        result = b""
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        pos = m.start()
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        for index, capture in enumerate(m.groups()):
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            index += 1  # re groups are conventionally 1-indexed
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            result += contents[pos : m.start(index)]
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            replacement = replace_one(capture, line, m.start(index))
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            result += replacement
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            if replacement == capture:
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                global failures
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                failures += 1
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            pos = m.end(index)
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        result += contents[pos : m.end()]
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        return result
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    for pattern in args.pattern:
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        contents = re.sub(pattern, replace_match, contents)
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    if failures > 0 and not args.partial:
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        print(f"{file}: leaving unchanged (some failed, --partial not given)")
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        continue
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    if not args.dry_run:
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        open(file, "wb").write(contents)
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