Re: [PATCH v2 01/29] displaced step: pass down target_waitstatus instead of gdb_signal

[Simon Marchi <simark@simark.ca>]

On 2022-07-13 18:24, Pedro Alves wrote:
> This commit tweaks displaced_step_finish & friends to pass down a
> target_waitstatus instead of a gdb_signal.  This needed because a
> patch later in the series will want to make
> displaced_step_buffers::finish handle TARGET_WAITKIND_THREAD_EXITED.
> It also helps with the TARGET_WAITKIND_THREAD_CLONED patch.
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
> Change-Id: I4c5d338647b028071bc498c4e47063795a2db4c0
> ---
>  gdb/displaced-stepping.c  | 11 ++++++-----
>  gdb/displaced-stepping.h  |  2 +-
>  gdb/gdbarch-components.py |  2 +-
>  gdb/gdbarch-gen.h         |  4 ++--
>  gdb/gdbarch.c             |  4 ++--
>  gdb/infrun.c              | 17 +++++++----------
>  gdb/linux-tdep.c          |  5 +++--
>  gdb/linux-tdep.h          |  2 +-
>  8 files changed, 23 insertions(+), 24 deletions(-)
> 
> diff --git a/gdb/displaced-stepping.c b/gdb/displaced-stepping.c
> index eac2c5dab94..83080cf6bdd 100644
> --- a/gdb/displaced-stepping.c
> +++ b/gdb/displaced-stepping.c
> @@ -174,10 +174,11 @@ write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
>  }
>  
>  static bool
> -displaced_step_instruction_executed_successfully (gdbarch *arch,
> -						  gdb_signal signal)
> +displaced_step_instruction_executed_successfully
> +  (gdbarch *arch, const target_waitstatus &status)
>  {
> -  if (signal != GDB_SIGNAL_TRAP)
> +  if (status.kind() == TARGET_WAITKIND_STOPPED

Missing space.

> +      && status.sig () != GDB_SIGNAL_TRAP)
>      return false;

The change here (combined with the one in infrun.c changes the
behavior), I just want to make sure this is what you intend.

Before, infrun did this:

	  sig = (event.ws.kind () == TARGET_WAITKIND_STOPPED
		 ? event.ws.sig () : GDB_SIGNAL_0);

So for event kinds kinds other than TARGET_WAITKIND_STOPPED, it passed
GDB_SIGNAL_0.  That would make us return false in
displaced_step_instruction_executed_successfully.

Now, we do this in displaced_step_instruction_executed_successfully:

  if (status.kind() == TARGET_WAITKIND_STOPPED
      && status.sig () != GDB_SIGNAL_TRAP)
    return false;

So a none-TARGET_WAITKIND_STOPPED event would not enter that if, and we
would return true.

Simon