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Message-ID: <0b1436d7f3f4267d518013919edd351dba4bcc92.camel@perches.com>
Subject: Re: [PATCH v3 01/56] scripts: kernel-doc: fix typedef parsing
From:   Joe Perches <joe@perches.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        linux-kernel@vger.kernel.org
Date:   Mon, 26 Oct 2020 20:55:35 -0700
In-Reply-To: <20201026080322.4d0b26f5@coco.lan>
References: <cover.1603469755.git.mchehab+huawei@kernel.org>
         <d0b2146c4ced3121342583bb3d962628fc96759b.1603469755.git.mchehab+huawei@kernel.org>
         <20201023112226.4035e3f7@lwn.net>
         <c0210eade81060382884e1f38ca7f71742d02b61.camel@perches.com>
         <20201026080322.4d0b26f5@coco.lan>
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On Mon, 2020-10-26 at 08:03 +0100, Mauro Carvalho Chehab wrote:
[]
> Well, this can help:
> 	my $typedef_type = qr { ((?:\w+\s+){1,}) }x;

unbounded captures are generally bad, I suggest a limit like {1,5}

> ????if ($x =~ /typedef\s+((?:\w+\s+){1,})\(\*?\s*(\w\S+)\s*\)\s*\((.*)\);/ ||
> 	$x =~ /typedef\s+((?:\w+\s+){1,})\s*\*?(\w\S+)\s*\s*\((.*)\);/) {
[]
> Fix the regex in order to accept composite types when
> defining a typedef for a function pointer.
[] 
> diff --git a/scripts/kernel-doc b/scripts/kernel-doc
[]
> @@ -1438,13 +1438,14 @@ sub dump_typedef($$) {
> ?????$x =~ s@/\*.*?\*/@@gos;	# strip comments.
> ?
> 
> ?????# Parse function prototypes
> -    if ($x =~ /typedef\s+(\w+)\s*\(\*\s*(\w\S+)\s*\)\s*\((.*)\);/ ||
> -	$x =~ /typedef\s+(\w+)\s*(\w\S+)\s*\s*\((.*)\);/) {
> +    if ($x =~ /typedef\s+((?:\w+\s+){1,})\(\*?\s*(\w\S+)\s*\)\s*\((.*)\);/ ||
> +	$x =~ /typedef\s+((?:\w+\s+){1,})\s*\*?(\w\S+)\s*\s*\((.*)\);/) {

This typedef does not allow * returns?like

	const unsigned char *(*string)(args...);
or
	unsigned char *const(*fn)(args...);
or
	void *(*alloc)(args...);

(not to mention the truly unusual stuff like the typedefs in
 tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c)

typedef void (* (*signal_t)(int, void (*)(int)))(int);
typedef char * (*fn_ptr_arr1_t[10])(int **);
typedef char * (* const (* const fn_ptr_arr2_t[5])())(char * (*)(int));