[PATCH 01/11] scripts: import Zephyr scripts/kconfig/lint.py into barebox

* [PATCH 01/11] scripts: import Zephyr scripts/kconfig/lint.py into barebox
@ 2020-04-28  7:37 Ahmad Fatoum
  2020-04-28  7:37 ` [PATCH 02/11] scripts: kconfig-lint.py: extend for undefined symbol detection Ahmad Fatoum
                   ` (10 more replies)
  0 siblings, 11 replies; 12+ messages in thread
From: Ahmad Fatoum @ 2020-04-28  7:37 UTC (permalink / raw)
  To: barebox

This kconfig linter can do some useful analysis to find problems
in our Kconfig files. Import it into barebox source tree with the
changes necessary to be usable.

The results of running it should be taken with a grain of salt and
verified with grep.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 scripts/kconfig-lint.py | 306 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 306 insertions(+)
 create mode 100755 scripts/kconfig-lint.py

diff --git a/scripts/kconfig-lint.py b/scripts/kconfig-lint.py
new file mode 100755
index 000000000000..308c82dfd8de
--- /dev/null
+++ b/scripts/kconfig-lint.py
@@ -0,0 +1,306 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2019 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Linter for the Zephyr Kconfig files. Pass --help to see
+available checks. By default, all checks are enabled.
+
+Some of the checks rely on heuristics and can get tripped up
+by things like preprocessor magic, so manual checking is
+still needed. 'git grep' is handy.
+"""
+
+import argparse
+import os
+import re
+import shlex
+import subprocess
+import sys
+import tempfile
+
+TOP_DIR = os.path.join(os.path.dirname(__file__), "..")
+
+import kconfiglib
+
+
+def main():
+    init_kconfig()
+
+    args = parse_args()
+    if args.checks:
+        checks = args.checks
+    else:
+        # Run all checks if no checks were specified
+        checks = (check_always_n,
+                  check_unused,
+                  check_pointless_menuconfigs,
+                  check_missing_config_prefix)
+
+    first = True
+    for check in checks:
+        if not first:
+            print()
+        first = False
+        check()
+
+
+def parse_args():
+    # args.checks is set to a list of check functions to run
+
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.RawTextHelpFormatter,
+        description=__doc__)
+
+    parser.add_argument(
+        "-n", "--check-always-n",
+        action="append_const", dest="checks", const=check_always_n,
+        help="""\
+List symbols that can never be anything but n/empty. These
+are detected as symbols with no prompt or defaults that
+aren't selected or implied.
+""")
+
+    parser.add_argument(
+        "-u", "--check-unused",
+        action="append_const", dest="checks", const=check_unused,
+        help="""\
+List symbols that might be unused.
+
+Heuristic:
+
+ - Isn't referenced in Kconfig
+ - Isn't referenced as CONFIG_<NAME> outside Kconfig
+   (besides possibly as CONFIG_<NAME>=<VALUE>)
+ - Isn't selecting/implying other symbols
+ - Isn't a choice symbol
+
+C preprocessor magic can trip up this check.""")
+
+    parser.add_argument(
+        "-m", "--check-pointless-menuconfigs",
+        action="append_const", dest="checks", const=check_pointless_menuconfigs,
+        help="""\
+List symbols defined with 'menuconfig' where the menu is
+empty due to the symbol not being followed by stuff that
+depends on it""")
+
+    parser.add_argument(
+        "-p", "--check-missing-config-prefix",
+        action="append_const", dest="checks", const=check_missing_config_prefix,
+        help="""\
+Look for references like
+
+    #if MACRO
+    #if(n)def MACRO
+    defined(MACRO)
+    IS_ENABLED(MACRO)
+
+where MACRO is the name of a defined Kconfig symbol but
+doesn't have a CONFIG_ prefix. Could be a typo.
+
+Macros that are #define'd somewhere are not flagged.""")
+
+    return parser.parse_args()
+
+
+def check_always_n():
+    print_header("Symbols that can't be anything but n/empty")
+    for sym in kconf.unique_defined_syms:
+        if not has_prompt(sym) and not is_selected_or_implied(sym) and \
+           not has_defaults(sym):
+            print(name_and_locs(sym))
+
+
+def check_unused():
+    print_header("Symbols that look unused")
+    referenced = referenced_sym_names()
+    for sym in kconf.unique_defined_syms:
+        if not is_selecting_or_implying(sym) and not sym.choice and \
+           sym.name not in referenced:
+            print(name_and_locs(sym))
+
+
+def check_pointless_menuconfigs():
+    print_header("menuconfig symbols with empty menus")
+    for node in kconf.node_iter():
+        if node.is_menuconfig and not node.list and \
+           isinstance(node.item, kconfiglib.Symbol):
+            print("{0.item.name:40} {0.filename}:{0.linenr}".format(node))
+
+
+def check_missing_config_prefix():
+    print_header("Symbol references that might be missing a CONFIG_ prefix")
+
+    # Paths to modules
+    modpaths = [TOP_DIR]
+
+    # Gather #define'd macros that might overlap with symbol names, so that
+    # they don't trigger false positives
+    defined = set()
+    for modpath in modpaths:
+        regex = r"#\s*define\s+([A-Z0-9_]+)\b"
+        defines = run(("git", "grep", "--extended-regexp", regex),
+                      cwd=modpath, check=False)
+        # Could pass --only-matching to git grep as well, but it was added
+        # pretty recently (2018)
+        defined.update(re.findall(regex, defines))
+
+    # Filter out symbols whose names are #define'd too. Preserve definition
+    # order to make the output consistent.
+    syms = [sym for sym in kconf.unique_defined_syms
+            if sym.name not in defined]
+
+    # grep for symbol references in #ifdef/defined() that are missing a CONFIG_
+    # prefix. Work around an "argument list too long" error from 'git grep' by
+    # checking symbols in batches.
+    for batch in split_list(syms, 200):
+        # grep for '#if((n)def) <symbol>', 'defined(<symbol>', and
+        # 'IS_ENABLED(<symbol>', with a missing CONFIG_ prefix
+        regex = r"(?:#\s*if(?:n?def)\s+|\bdefined\s*\(\s*|IS_ENABLED\(\s*)(?:" + \
+                "|".join(sym.name for sym in batch) + r")\b"
+        cmd = ("git", "grep", "--line-number", "-I", "--perl-regexp", regex)
+
+        for modpath in modpaths:
+            print(run(cmd, cwd=modpath, check=False), end="")
+
+
+def split_list(lst, batch_size):
+    # check_missing_config_prefix() helper generator that splits a list into
+    # equal-sized batches (possibly with a shorter batch at the end)
+
+    for i in range(0, len(lst), batch_size):
+        yield lst[i:i + batch_size]
+
+
+def print_header(s):
+    print(s + "\n" + len(s)*"=")
+
+
+def init_kconfig():
+    global kconf
+
+    os.environ.update(
+        srctree=TOP_DIR,
+        KCONFIG_DOC_MODE="1",
+        ARCH_DIR="arch",
+        SRCARCH="*")
+
+    kconf = kconfiglib.Kconfig(suppress_traceback=True)
+
+
+def referenced_sym_names():
+    # Returns the names of all symbols referenced inside and outside the
+    # Kconfig files (that we can detect), without any "CONFIG_" prefix
+
+    return referenced_in_kconfig() | referenced_outside_kconfig()
+
+
+def referenced_in_kconfig():
+    # Returns the names of all symbols referenced inside the Kconfig files
+
+    return {ref.name
+            for node in kconf.node_iter()
+                for ref in node.referenced
+                    if isinstance(ref, kconfiglib.Symbol)}
+
+
+def referenced_outside_kconfig():
+    # Returns the names of all symbols referenced outside the Kconfig files
+
+    regex = r"\bCONFIG_[A-Z0-9_]+\b"
+
+    res = set()
+
+    # 'git grep' all modules
+    for modpath in [TOP_DIR]:
+        for line in run(("git", "grep", "-h", "-I", "--extended-regexp", regex),
+                        cwd=modpath).splitlines():
+            # Don't record lines starting with "CONFIG_FOO=" or "# CONFIG_FOO="
+            # as references, so that symbols that are only assigned in .config
+            # files are not included
+            if re.match(r"[\s#]*CONFIG_[A-Z0-9_]+=.*", line):
+                continue
+
+            # Could pass --only-matching to git grep as well, but it was added
+            # pretty recently (2018)
+            for match in re.findall(regex, line):
+                res.add(match[7:])  # Strip "CONFIG_"
+
+    return res
+
+
+def has_prompt(sym):
+    return any(node.prompt for node in sym.nodes)
+
+
+def is_selected_or_implied(sym):
+    return sym.rev_dep is not kconf.n or sym.weak_rev_dep is not kconf.n
+
+
+def has_defaults(sym):
+    return bool(sym.defaults)
+
+
+def is_selecting_or_implying(sym):
+    return sym.selects or sym.implies
+
+
+def name_and_locs(sym):
+    # Returns a string with the name and definition location(s) for 'sym'
+
+    return "{:40} {}".format(
+        sym.name,
+        ", ".join("{0.filename}:{0.linenr}".format(node) for node in sym.nodes))
+
+
+def run(cmd, cwd=TOP_DIR, check=True):
+    # Runs 'cmd' with subprocess, returning the decoded stdout output. 'cwd' is
+    # the working directory. It defaults to the top-level Zephyr directory.
+    # Exits with an error if the command exits with a non-zero return code if
+    # 'check' is True.
+
+    cmd_s = " ".join(shlex.quote(word) for word in cmd)
+
+    try:
+        process = subprocess.Popen(
+            cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd)
+    except OSError as e:
+        err("Failed to run '{}': {}".format(cmd_s, e))
+
+    stdout, stderr = process.communicate()
+    # errors="ignore" temporarily works around
+    # https://github.com/zephyrproject-rtos/esp-idf/pull/2
+    stdout = stdout.decode("utf-8", errors="ignore")
+    stderr = stderr.decode("utf-8")
+    if check and process.returncode:
+        err("""\
+'{}' exited with status {}.
+
+===stdout===
+{}
+===stderr===
+{}""".format(cmd_s, process.returncode, stdout, stderr))
+
+    if stderr:
+        warn("'{}' wrote to stderr:\n{}".format(cmd_s, stderr))
+
+    return stdout
+
+
+def err(msg):
+    sys.exit(executable() + "error: " + msg)
+
+
+def warn(msg):
+    print(executable() + "warning: " + msg, file=sys.stderr)
+
+
+def executable():
+    cmd = sys.argv[0]  # Empty string if missing
+    return cmd + ": " if cmd else ""
+
+
+if __name__ == "__main__":
+    main()
-- 
2.20.1


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