Re: [PATCH] Map registers to remote numbers when encoding an ax_reg or ax_reg_mask operation

[Pedro Alves <palves@redhat.com>]

On 02/25/2016 01:25 PM, Antoine Tremblay wrote:
> When encoding the agent expression operation ax_reg or ax_reg_mask, the
> register number used is internal to GDB. However GDBServer expects a tdesc
> based number.
> 
> This usually does not cause a problem since at the moment, for raw
> registers GDBServer R trace action ignores the register mask and just
> collects all registers.
> 
> It can be a problem, however with pseudo registers on some platforms if the
> tdesc number doesn't match the GDB internal register number.
> 
> This is the case with ARM, the upcoming ARM tracepoint support, fails
> these test cases without this patch:
> 
> gdb.trace/collection.exp: collect register locals collectively:*
> 
> GDBSever would exit with: unhandled register size
> Since the register number is not mapped.
> 
> This patch fixes these issues by calling gdbarch_remote_register_number
> before encoding the register number in the ax_reg or ax_reg_mask operation.
> 
> Tested on x86 native-gdbserver no regressions observed.

>    else
>      {
> -      int byte = reg / 8;
> +      int byte = 0;

No need to zero initialize.

> +
> +      /* Get the remote register number.  */
> +      reg = gdbarch_remote_register_number (ax->gdbarch, reg);
> +      byte = reg / 8;
>  
>        /* Grow the bit mask if necessary.  */
>        if (byte >= ax->reg_mask_len)
> 

OK with ChangeLog entry.

Thanks,
Pedro Alves