From 3943828cef976d2fe296cdd3a1c26089068b14e3 Mon Sep 17 00:00:00 2001
From: Richard Patel <me@terorie.dev>
Date: Mon, 28 Mar 2022 07:59:04 +0200
Subject: [PATCH] Basic inline asm linter (#160)

---
 mkwutil/tools/lint_inline_asm.py | 142 +++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 mkwutil/tools/lint_inline_asm.py

diff --git a/mkwutil/tools/lint_inline_asm.py b/mkwutil/tools/lint_inline_asm.py
new file mode 100644
index 000000000..fe10336e6
--- /dev/null
+++ b/mkwutil/tools/lint_inline_asm.py
@@ -0,0 +1,142 @@
+#!/usr/bin/env python3
+
+"""
+A dumb little linter for inline assembly.
+"""
+
+from abc import ABC, abstractmethod
+import argparse
+from dataclasses import dataclass
+import os
+from pathlib import Path
+import re
+from typing import Iterator, Optional
+import sys
+
+import colorama
+from termcolor import cprint
+
+
+@dataclass
+class LintViolation:
+    """An instance of a lint violation."""
+
+    col_start: int
+    col_stop: int
+    msg: str
+    line: int = -1
+    file: str = ""
+
+
+class Source:
+    """A source code file, line by line."""
+
+    lines: list[str]
+
+    def __init__(self, path):
+        with open(path, "r") as source_file:
+            self.lines = [line.rstrip("\r\n") for line in source_file.readlines()]
+
+
+class BaseLineRule(ABC):
+    """Base class for lint rules that operate line-by-line."""
+
+    def process(self, source: Source) -> Iterator[LintViolation]:
+        for i, line in enumerate(source.lines):
+            violation = self.process_line(line)
+            if violation:
+                violation.line = i
+                yield violation
+
+    @abstractmethod
+    def process_line(self, line: str) -> Optional[LintViolation]:
+        pass
+
+
+class BaseRegexRule(BaseLineRule):
+    def __init__(self, rule_name: str, pattern: str):
+        self.rule_name = rule_name
+        self.pattern = re.compile(pattern)
+
+    def process_line(self, line: str) -> Optional[LintViolation]:
+        match = self.pattern.match(line)
+        if match:
+            start, stop = match.span()
+            return LintViolation(start, stop-1, self.rule_name)
+
+
+SdataAbsoluteRule = BaseRegexRule(
+    "sdata/sbss reference",
+    r"^\s+((?:lwz|stw|lhz|lha|sth|lbz|stb) r\d{1,2}, -?0x[0-9a-f]+\(r13\));.*$",
+)
+Sdata2AbsoluteRule = BaseRegexRule(
+    "sdata2 reference",
+    r"^\s+((?:lfs|lfd|lhz) [rf]\d{1,2}, -?0x[0-9a-f]+\(r2\));.*$",
+)
+
+
+class LintBasicFormatter:
+    def print(self, source: Source, lint: LintViolation):
+        print(f"{lint.file}:{lint.line+1} {lint.msg}")
+
+
+class LintPrettyFormatter:
+    def print(self, source: Source, lint: LintViolation):
+        cprint(f"{lint.msg}", "white", attrs=["bold"], end="")
+        cprint(f" in {lint.file}:{lint.line+1}", "white")
+        self._print_line(source, lint, lint.line - 1)
+        self._print_line(source, lint, lint.line)
+        self._print_line(source, lint, lint.line + 1)
+        print()
+
+    def _print_line(self, source: Source, lint: LintViolation, line: int):
+        if source.lines[line] is None:
+            return
+        cprint("% 5d > " % (line + 1), "white", attrs=["dark"], end="")
+        line_str = source.lines[line]
+        if lint.line == line:
+            cprint(line_str[: lint.col_start], end="")
+            cprint(
+                line_str[lint.col_start : lint.col_stop], "red", attrs=["bold"], end=""
+            )
+            cprint(line_str[lint.col_stop :])
+        else:
+            cprint(line_str)
+
+
+def get_lint_formatter():
+    if os.isatty(sys.stdout.fileno()):
+        colorama.init()
+        return LintPrettyFormatter()
+    else:
+        return LintBasicFormatter()
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("file", type=str, nargs="+", help="File paths to lint")
+    args = parser.parse_args()
+
+    # Collect list of source paths, respecting wildcards.
+    source_paths = []
+    root_dir = Path(".")
+    for file_path in args.file:
+        source_paths.extend(
+            path_obj for path_obj in root_dir.glob(file_path) if path_obj.is_file()
+        )
+
+    linters = [
+        SdataAbsoluteRule,
+        Sdata2AbsoluteRule,
+    ]
+    formatter = get_lint_formatter()
+    for source_path in source_paths:
+        source = Source(source_path)
+        for linter in linters:
+            for violation in linter.process(source):
+                violation.file = str(source_path)
+                formatter.print(source, violation)
+
+
+if __name__ == "__main__":
+    main()