Re: [PATCH 2/2] gdb, multi-target: pass a target argument to delete_exited_threads

[Simon Marchi <simark@simark.ca>]

On 4/17/26 7:14 AM, Tankut Baris Aktemur wrote:
> Similar to the parent commit, delete_exited_threads is also mostly
> used in the context of a particular target.  Pass that target as a
> parameter and skip other targets.
> 
> There seems to be two cases where we actually would want to iterate
> all targets.  One use is in inferior_appeared (inferior.c) and the
> other is in thread_select (thread.c).  To handle these cases, allow
> the argument to be nullptr.
> ---
>  gdb/fbsd-nat.c   |  2 +-
>  gdb/gdbthread.h  |  6 +++---
>  gdb/inferior.c   |  2 +-
>  gdb/linux-nat.c  |  2 +-
>  gdb/netbsd-nat.c |  2 +-
>  gdb/thread.c     | 14 ++++++++++----
>  6 files changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
> index a1c7801ec1e..706d6efd342 100644
> --- a/gdb/fbsd-nat.c
> +++ b/gdb/fbsd-nat.c
> @@ -1004,7 +1004,7 @@ fbsd_nat_target::update_thread_list ()
>  #ifdef PT_LWP_EVENTS
>    /* With support for thread events, threads are added/deleted from the
>       list as events are reported, so just try deleting exited threads.  */
> -  delete_exited_threads ();
> +  delete_exited_threads (this);
>  #else
>    prune_threads (this);
>  
> diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
> index 835d07dc660..3bd9598907d 100644
> --- a/gdb/gdbthread.h
> +++ b/gdb/gdbthread.h
> @@ -969,9 +969,9 @@ extern void update_thread_list (void);
>  extern void prune_threads (process_stratum_target *target);
>  
>  /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
> -   does not consult the target about whether the thread is alive right
> -   now.  */
> -extern void delete_exited_threads (void);
> +   does not consult TARGET about whether the thread is alive right
> +   now.  If TARGET is nullptr, operate on all targets.  */
> +extern void delete_exited_threads (process_stratum_target *target);
>  
>  /* Return true if PC is in the stepping range of THREAD.  */
>  
> diff --git a/gdb/inferior.c b/gdb/inferior.c
> index e050dec402e..1481f46cdd1 100644
> --- a/gdb/inferior.c
> +++ b/gdb/inferior.c
> @@ -368,7 +368,7 @@ inferior_appeared (struct inferior *inf, int pid)
>  {
>    /* If this is the first inferior with threads, reset the global
>       thread id.  */
> -  delete_exited_threads ();
> +  delete_exited_threads (nullptr);
>    if (!any_thread_p ())
>      init_thread_list ();
>  
> diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
> index f141ba19ea4..5ac61316445 100644
> --- a/gdb/linux-nat.c
> +++ b/gdb/linux-nat.c
> @@ -3963,7 +3963,7 @@ linux_nat_target::update_thread_list ()
>    /* We add/delete threads from the list as clone/exit events are
>       processed, so just try deleting exited threads still in the
>       thread list.  */
> -  delete_exited_threads ();
> +  delete_exited_threads (this);
>  
>    /* Update the processor core that each lwp/thread was last seen
>       running on.  */
> diff --git a/gdb/netbsd-nat.c b/gdb/netbsd-nat.c
> index 6b9029bf0ef..36bd91f968c 100644
> --- a/gdb/netbsd-nat.c
> +++ b/gdb/netbsd-nat.c
> @@ -155,7 +155,7 @@ nbsd_nat_target::post_attach (int pid)
>  void
>  nbsd_nat_target::update_thread_list ()
>  {
> -  delete_exited_threads ();
> +  delete_exited_threads (this);
>  }
>  
>  /* Convert PTID to a string.  */
> diff --git a/gdb/thread.c b/gdb/thread.c
> index 861eca3591d..4e1f1ad17ac 100644
> --- a/gdb/thread.c
> +++ b/gdb/thread.c
> @@ -785,11 +785,17 @@ prune_threads (process_stratum_target *target)
>  /* See gdbthreads.h.  */
>  
>  void
> -delete_exited_threads (void)
> +delete_exited_threads (process_stratum_target *target)
>  {
>    for (thread_info &tp : all_threads_safe ())
> -    if (tp.state () == THREAD_EXITED)
> -      delete_thread (&tp);
> +    {
> +      if (target != nullptr
> +	  && tp.inf->process_target () != target)
> +	continue;

We have "all_threads", which takes an optional target pointer (to do
exactly what you are doing here), and all_threads_safe, which doesn't
take a target.  Could you check if it's relatively easy to make
all_threads_safe accept a target too?

Simon