[PATCH] gdb: add debug prints in remote_check_symbols

[Luis Machado]

I think the debugging output is great, but I'm not sure if using the 
same option that enables RSP debugging output is the best option.

On 4/16/21 12:00 PM, Simon Marchi via Gdb-patches wrote:
> While debugging a libthread_db issue against gdbserver, I added these
> debug prints, which help to read the symbols names (which are
> hex-encoded in the packets).  I'd like to merge that upstream, I think
> it may be useful in the future.
> 
> Before:
> 
>    [remote] Sending packet: $qSymbol::#5b
>    [remote] Packet received: qSymbol:6764625f6167656e745f6764625f74705f686561705f627566666572
>    [remote] Sending packet: $qSymbol::6764625f6167656e745f6764625f74705f686561705f627566666572#1e
>    [remote] Packet received: qSymbol:6e70746c5f76657273696f6e
>    [remote] Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d
>    [remote] Packet received: OK
> 
> After:
> 
>    [remote] remote_check_symbols: enter
>      [remote] Sending packet: $qSymbol::#5b
>      [remote] Packet received: qSymbol:6764625f6167656e745f6764625f74705f686561705f627566666572
>      [remote] remote_check_symbols: asked for symbol: gdb_agent_gdb_tp_heap_buffer
>      [remote] remote_check_symbols:   -> not found
>      [remote] Sending packet: $qSymbol::6764625f6167656e745f6764625f74705f686561705f627566666572#1e
>      [remote] Packet received: qSymbol:6e70746c5f76657273696f6e
>      [remote] remote_check_symbols: asked for symbol: nptl_version
>      [remote] remote_check_symbols:   -> not found
>      [remote] Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d
>      [remote] Packet received: OK
>    [remote] remote_check_symbols: exit
> 
> gdb/ChangeLog:
> 
> 	* remote.c (remote_target::remote_check_symbols): Add debug
> 	prints.
> 
> Change-Id: Ia05b61285259a7d1570ec6bacfc9700d5baf129e
> ---
>   gdb/remote.c | 17 ++++++++++++++---
>   1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/gdb/remote.c b/gdb/remote.c
> index 7429e1a86b38..96325531d51d 100644
> --- a/gdb/remote.c
> +++ b/gdb/remote.c
> @@ -5035,6 +5035,8 @@ remote_target::remote_check_symbols ()
>     char *tmp;
>     int end;
>   
> +  REMOTE_SCOPED_DEBUG_ENTER_EXIT;
> +
>     /* The remote side has no concept of inferiors that aren't running
>        yet, it only knows about running processes.  If we're connected
>        but our current inferior is not running, we should not invite the
> @@ -5069,19 +5071,28 @@ remote_target::remote_check_symbols ()
>         end = hex2bin (tmp, reinterpret_cast <gdb_byte *> (msg.data ()),
>   		     strlen (tmp) / 2);
>         msg[end] = '\0';
> +
> +      remote_debug_printf ("asked for symbol: %s", msg.data ());
> +
>         sym = lookup_minimal_symbol (msg.data (), NULL, NULL);
>         if (sym.minsym == NULL)
> -	xsnprintf (msg.data (), get_remote_packet_size (), "qSymbol::%s",
> -		   &reply[8]);
> +	{
> +	  remote_debug_printf ("  -> not found");
> +	  xsnprintf (msg.data (), get_remote_packet_size (), "qSymbol::%s",
> +		     &reply[8]);
> +	}
>         else
>   	{
>   	  int addr_size = gdbarch_addr_bit (target_gdbarch ()) / 8;
>   	  CORE_ADDR sym_addr = BMSYMBOL_VALUE_ADDRESS (sym);
> +	  gdbarch *arch = target_gdbarch ();
>   
>   	  /* If this is a function address, return the start of code
>   	     instead of any data function descriptor.  */
>   	  sym_addr = gdbarch_convert_from_func_ptr_addr
> -	    (target_gdbarch (), sym_addr, current_inferior ()->top_target ());
> +	    (arch, sym_addr, current_inferior ()->top_target ());
> +
> +	  remote_debug_printf ("  -> found %s", paddress (arch, sym_addr));
>   
>   	  xsnprintf (msg.data (), get_remote_packet_size (), "qSymbol:%s:%s",
>   		     phex_nz (sym_addr, addr_size), &reply[8]);
>