Re: [PATCH v3 01/56] scripts: kernel-doc: fix typedef parsing

[Joe Perches <joe@perches.com>]

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));