[Mesa-dev] [PATCH] glsl/list: Add an exec_list_validate function

[Matt Turner]

On Wed, Nov 5, 2014 at 2:00 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> This can be very useful for trying to debug list corruptions.
>
> Signed-off-by: Jason Ekstrand <jason.ekstrand at intel.com>
> Cc: Ian Romanick <idr at freedesktop.org>
> ---
>  src/glsl/list.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/src/glsl/list.h b/src/glsl/list.h
> index aac13fd..1d18ec9 100644
> --- a/src/glsl/list.h
> +++ b/src/glsl/list.h
> @@ -521,6 +521,20 @@ exec_node_insert_list_before(struct exec_node *n, struct exec_list *before)
>     exec_list_make_empty(before);
>  }
>
> +static inline void
> +exec_list_validate(struct exec_list *list)
> +{
> +   assert(list->head->prev == (struct exec_node *) &list->head);
> +   assert(list->tail == NULL);
> +   assert(list->tail_pred->next == (struct exec_node *) &list->tail);
> +
> +   for (struct exec_node *node = list->head;
> +        node->next != NULL; node = node->next) {

Just use foreach_in_list().

> +      assert(node->next->prev == node);
> +      assert(node->prev->next == node);
> +   }
> +}

Are you intending to call this from gdb? I'm having a hard time
imagining committing code that *sometimes* corrupts lists, which seems
like why this function would be useful to call from real code.

If you just want to call it from gdb, wrap the whole thing in #ifndef
NDEBUG. I don't want to ever accidentally call this function and think
it validated something when it actually did nothing.