Re: [patch] Skip kill-after-signal.exp if hw single-step is not supported

[Matthew Gretton-Dann <matthew.gretton-dann@arm.com>]

On 09/08/11 15:32, Yao Qi wrote:
> On 07/24/2011 06:47 AM, Mark Kettenis wrote:
>>> From: Pedro Alves<pedro@codesourcery.com>
>>> Date: Wed, 20 Jul 2011 16:05:43 +0100
>>>
>>> Other archs !x86, and other kernels/stubs/servers !Linux that
>>> can do hardware stepping.  If we're going to have a list, invert
>>> the logic of the check, defaulting to running the test, and leaving
>>> out archs were we know software stepping is used.  Some targets,
>>> like x86/OpenBSD and MacOS, although can hardware step, can't step
>>> into a handler.
>>
>> Just FYI, it's putting breakpoints into the signal trampoline that is
>> the issue, at least on OpenBSD.  Single-stepping should work fine on
>> OpenBSD/i386 and OpenBSD/amd64 and all other architectures where it's
>> done in hardware.
>
> This is the 2nd version of the patch.  A new predicate,
> single_step_to_signal_handler_p, is added in lib/gdb.exp.  In default,
> it returns true, and return false on target "arm*-*-* and "mips*-*-*".
>
> I don't find any other tests using "stepi" to step into signal handler,
> so I only changed kill-after-signal.exp.
>
> OK for mainline?
>
>
>
> single_step_to_signal_handler_p.patch
>
>
>
> gdb/testsuite/
>
> 	* lib/gdb.exp (single_step_to_signal_handler_p): New.
> 	* gdb.base/kill-after-signal.exp: Skip if target supports single step
> 	to signal handler.
>
> diff --git a/gdb/testsuite/gdb.base/kill-after-signal.exp b/gdb/testsuite/gdb.base/kill-after-signal.exp
> index eecad2e..f7086fc 100644
> --- a/gdb/testsuite/gdb.base/kill-after-signal.exp
> +++ b/gdb/testsuite/gdb.base/kill-after-signal.exp
> @@ -14,6 +14,12 @@
>   # along with this program.  If not, see<http://www.gnu.org/licenses/>.
>
>   set testfile "kill-after-signal"
> +
> +if { ![single_step_to_signal_handler_p] } {
> +    untested ${testfile}.exp
> +    return
> +}
> +
>   if [prepare_for_testing ${testfile}.exp ${testfile}] {
>       return -1
>   }
> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
> index ef5ad5c..b967a97 100644
> --- a/gdb/testsuite/lib/gdb.exp
> +++ b/gdb/testsuite/lib/gdb.exp
> @@ -1527,6 +1527,21 @@ proc support_complex_tests {} {
>       return $support_complex_tests_saved
>   }
>
> +# Return 1 if target hardware or OS supports single stepping to single handler,
> +# otherwise, return 0.
> +
> +proc single_step_to_signal_handler_p {} {
> +
> +    # Targets don't have hardware single step.  On these targets, when a signal
> +    # is delivered during software single step, gdb is unable to determine the
> +    # next instruction addresses, because start of signal handler is one of them.
> +    if { [istarget "arm*-*-*"] || [istarget "mips*-*-*"] } {
> +	return 0
> +    }
> +
> +    return 1
> +}
> +

Would this be better if it followed the pattern of the 
skip_hw_breakpoint_tests and skip_hw_watchpoint_tests family of 
functions in gdb.exp?

So I would rename the function to skip_hw_single_step_tests[1], and test 
for the existence of gdb,no_hardware_watchpoints in the board info.

[1] Although for the use you are putting it to this is possibly a 
confusing name.

Thanks,

Matt


-- 
Matthew Gretton-Dann
Principal Engineer, PD Software - Tools, ARM Ltd