Re: [PATCH 3/3] gdb/testsuite: Handle targets with lots of registers

["Maciej W. Rozycki" <macro@mips.com>]

On Mon, 9 Apr 2018, Andrew Burgess wrote:

>  # Test for a regression where this command would internal-error if the
> -# program wasn't running.
> -gdb_test "maint print registers" "Name.*Nr.*Rel.*Offset.*Size.*Type.*"
> +# program wasn't running.  If there's a lot of registers then this
> +# might overflow expect's buffers, so process the output line at a
> +# time.
> +send_gdb "maint print registers\n"
> +gdb_expect {
> +    -re "^\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[\n\r\]+" {
> +	exp_continue
> +    }

 I think this changes the meaning of the test; you want to preserve the 
heading match pattern at the very least.  Also `gdb_test' handles various 
error cases gracefully (which matters for the avoidance of excessive 
timeouts with some test boards), whereas your simple matcher does not.

 Also how many is "a lot"?  Perhaps you could take the path of least 
resistance instead and simply increase the size of the buffer, like with 
commit ff604a674771 ("gdb/testsuite: Bump up `match_max'").  This could be 
done temporarily for this test only, so as to avoid slowing down `expect' 
throughout the test suite.

  Maciej