Re: [PATCH 8/8] Fix removing inferiors from within "thread apply" commands

[Yao Qi <qiyaoltc@gmail.com>]

Pedro Alves <palves@redhat.com> writes:

> @@ -313,9 +319,31 @@ public:
>    explicit inferior (int pid);
>    ~inferior ();
>  
> +  /* Returns true if we can delete this inferior.  We can't delete it
> +     if it is the current inferior, or if there's code out there that
> +     relies on it existing (m_refcount > 0).  */
> +  bool deletable () const
> +  {
> +    return m_refcount == 0 && this != current_inferior ();
> +  }
> +
>    /* Pointer to next inferior in singly-linked list of inferiors.  */
>    struct inferior *next = NULL;
>  
> +  /* Increase the refcount.  */
> +  void incref ()
> +  {
> +    gdb_assert (m_refcount >= 0);
> +    m_refcount++;
> +  }
> +
> +  /* Decrease the refcount.  */
> +  void decref ()
> +  {
> +    m_refcount--;
> +    gdb_assert (m_refcount >= 0);
> +  }
> +
>    /* Convenient handle (GDB inferior id).  Unique across all
>       inferiors.  */
>    int num = 0;
> @@ -431,6 +459,12 @@ public:
>  
>    /* Per inferior data-pointers required by other GDB modules.  */
>    REGISTRY_FIELDS;
> +
> +private:
> +  /* If this is > 0, then it means there's code out there that relies
> +     on this inferior existing.  Don't allow deleting it in that
> +     case.  */
> +  int m_refcount = 0;
>  };

Can we move them to a super class, so that both thread and inferior can
extend it?

>  
> -/* Switch from one thread to another.  */
> +/* Switch to no thread selected.  */
>  
> -void
> -switch_to_thread (ptid_t ptid)
> +static void
> +switch_to_no_thread ()
>  {
> -  /* Switch the program space as well, if we can infer it from the now
> -     current thread.  Otherwise, it's up to the caller to select the
> -     space it wants.  */
> -  if (ptid != null_ptid)
> -    {
> -      struct inferior *inf;
> +  if (inferior_ptid == null_ptid)
> +    return;
>  
> -      inf = find_inferior_ptid (ptid);
> -      gdb_assert (inf != NULL);
> -      set_current_program_space (inf->pspace);
> -      set_current_inferior (inf);
> -    }
> +  inferior_ptid = null_ptid;
> +  reinit_frame_cache ();
> +  stop_pc = ~(CORE_ADDR) 0;
> +}
>  
> -  if (ptid == inferior_ptid)
> +/* Switch from one thread to another.  */
> +
> +static void
> +switch_to_thread (thread_info *thr)
> +{
> +  gdb_assert (thr != NULL);
> +
> +  if (inferior_ptid == thr->ptid)
>      return;
>  
> -  inferior_ptid = ptid;
> +  /* Switch the current program space and current inferior as
> +     well.  */
> +  set_current_program_space (thr->inf->pspace);
> +  set_current_inferior (thr->inf);
> +
> +  inferior_ptid = thr->ptid;

Can these code be replaced by switch_to_thread_no_regs?

-- 
Yao (齐尧)