Em Tue, Nov 30, 2021 at 04:42:55PM +0000, Douglas Raillard escreveu:
> On 11/26/21 6:27 PM, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Oct 19, 2021 at 11:07:23AM +0100, Douglas RAILLARD escreveu:
> > > From: Douglas Raillard <douglas.raillard@xxxxxxx>
> > >
> > > Allow making inner struct enums and union anonymous.
> >
> > So I had to apply it by hand due to changes in the areas it touches, see
> > below, and I expanded a bit the commit message, please review:
>
> Thanks for the review, it seems to be working as well as before. That said I found a couple of issues:
>
> 1. CLI options seem to abbreviate "anonymous" into "anon" so maybe we should do the same for this one ?
Ok, I can shorten the option name here.
> 2. I just found a case that generates a broken header:
>
> struct /* hrtimer */ {
> struct /* timerqueue_node */ {
> struct /* rb_node */ {
> long unsigned int __rb_parent_color; /* 3328 8 */
> struct rb_node * rb_right; /* 3336 8 */
> struct rb_node * rb_left; /* 3344 8 */
> }node; /* 3328 24 */
> /* typedef ktime_t -> s64 -> __s64 */ long long int expires; /* 3352 8 */
> }node; /* 3328 32 */
> /* typedef ktime_t -> s64 -> __s64 */ long long int _softexpires; /* 3360 8 */
> enum hrtimer_restart (*function)(struct hrtimer *); /* 3368 8 */
> struct hrtimer_clock_base * base; /* 3376 8 */
> /* typedef u8 -> __u8 */ unsigned char state; /* 3384 1 */
> /* typedef u8 -> __u8 */ unsigned char is_rel; /* 3385 1 */
> /* typedef u8 -> __u8 */ unsigned char is_soft; /* 3386 1 */
> /* typedef u8 -> __u8 */ unsigned char is_hard; /* 3387 1 */
> }hrtick_timer; /* 3328 64 */
>
> Here we can see that "struct rb_node" is a recursive type, so since the type
> definition is now anonymous it will not compile. Detecting recursive types and
> printing the name would avoid that but defeats the original purpose
> of --inner_anonymous.
>
> I can see two solutions:
>
> 1. Detecting recursive types and appending a user-defined prefix to create a
> unique name.
> 2. Detecting recursive types and replacing the recursive references by "void *".
> Solution #2 is the least invasive but will require a bit more work for the
> end-user of the header:
>
> struct hrtimer foo = *ptr;
> typeof(foo.node.node) node = foo.node.node;
> // Extra cast using typeof in order to change the type of tb_right from void*
> // to "struct rb_node*"
> ((typeof(node))node.rb_right)->rb_left
A third solution and probably the easiest to implement. If you don't
punch a hole on it:
Track if the struct is being printed the first time and then flip a bit
not to print it again?
$ cat inner_anon.c
struct foo {
struct baz {
struct rb_node {
struct rb_node *prev, *next;
} yy;
} y;
struct /* rb_node */ {
struct rb_node *prev, *next;
} x;
} i;
$ cc -c inner_anon.c -o inner_anon.o
$ vim inner_anon.c
$ cat inner_anon.c
struct foo {
struct rb_node {
struct rb_node *prev, *next;
} x;
struct baz {
struct /* rb_node */ {
struct rb_node *prev, *next;
} yy;
} y;
} i;
$ cc -c inner_anon.c -o inner_anon.o
$
