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From:   Ariel Marcovitch <arielmarcovitch@gmail.com>
Cc:     Ariel Marcovitch <arielmarcovitch@gmail.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] checkkconfigsymbols.py: Fix Kconfig parsing to find 'if' lines
Date:   Sun, 22 Aug 2021 22:22:02 +0300
Message-Id: <20210822192205.43210-3-arielmarcovitch@gmail.com>
In-Reply-To: <20210822192205.43210-1-arielmarcovitch@gmail.com>
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When parsing Kconfig files to find symbol definitions and references,
lines after a 'help' line are skipped until a new config definition
starts.

However, it is quite common to define a config and then make some other
configs depend on it by adding an 'if' line. This kind of kconfig
statement usually appears after a config definition which might contain
a 'help' section. The 'if' line is skipped in parse_kconfig_file()
because it is not a config definition.

This means that symbols referenced in this kind of statements are
ignored by this function and thus are not considered undefined
references in case the symbol is not defined.

The REGEX_KCONFIG_STMT regex can't be used because the other types of
statements can't break help lines.

Define a new regex for matching 'if' statements and stop the 'help'
skipping in case it is encountered.

Signed-off-by: Ariel Marcovitch <arielmarcovitch@gmail.com>
---
 scripts/checkkconfigsymbols.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/scripts/checkkconfigsymbols.py b/scripts/checkkconfigsymbols.py
index b9b0f15e5880..875e9a2c14b2 100755
--- a/scripts/checkkconfigsymbols.py
+++ b/scripts/checkkconfigsymbols.py
@@ -26,6 +26,7 @@ EXPR = r"(?:" + OPERATORS + r"|\s|" + SYMBOL + r")+"
 DEFAULT = r"default\s+.*?(?:if\s.+){,1}"
 STMT = r"^\s*(?:if|select|imply|depends\s+on|(?:" + DEFAULT + r"))\s+" + EXPR
 SOURCE_SYMBOL = r"(?:\W|\b)+[D]{,1}CONFIG_(" + SYMBOL + r")"
+IF_LINE = r"^\s*(?:if)\s+" + EXPR
 
 # regex objects
 REGEX_FILE_KCONFIG = re.compile(r".*Kconfig[\.\w+\-]*$")
@@ -35,11 +36,11 @@ REGEX_KCONFIG_DEF = re.compile(DEF)
 REGEX_KCONFIG_EXPR = re.compile(EXPR)
 REGEX_KCONFIG_STMT = re.compile(STMT)
 REGEX_KCONFIG_HELP = re.compile(r"^\s+help\s*$")
+REGEX_KCONFIG_IF_LINE = re.compile(IF_LINE)
 REGEX_FILTER_SYMBOLS = re.compile(r"[A-Za-z0-9]$")
 REGEX_NUMERIC = re.compile(r"0[xX][0-9a-fA-F]+|[0-9]+")
 REGEX_QUOTES = re.compile("(\"(.*?)\")")
 
-
 def parse_options():
     """The user interface of this module."""
     usage = "Run this tool to detect Kconfig symbols that are referenced but " \
@@ -445,6 +446,11 @@ def parse_kconfig_file(kfile):
         line = line.strip('\n')
         line = line.split("#")[0]  # ignore comments
 
+        # 'if EXPR' lines can be after help lines
+        # The if line itself is handled later
+        if REGEX_KCONFIG_IF_LINE.match(line):
+            skip = False
+
         if REGEX_KCONFIG_DEF.match(line):
             symbol_def = REGEX_KCONFIG_DEF.findall(line)
             defined.append(symbol_def[0])
-- 
2.25.1