Re: [python] Allow explicit locations in breakpoints.

[Phil Muldoon <pmuldoon@redhat.com>]

On 23/08/17 18:51, Keith Seitz wrote:
> On 08/23/2017 06:58 AM, Phil Muldoon wrote:
> 
>> diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
>> index 6156eb6179..8431bed939 100644
>> --- a/gdb/python/py-breakpoint.c
>> +++ b/gdb/python/py-breakpoint.c
>> @@ -681,7 +681,7 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
>>  	case bp_breakpoint:
>>  	  {
>>  	    event_location_up location
>> -	      = string_to_event_location_basic (&copy, current_language);
>> +	      = string_to_event_location (&copy, current_language);
>>  	    create_breakpoint (python_gdbarch,
>>  			       location.get (), NULL, -1, NULL,
>>  			       0,
> 
> This binds python interfaces to the CLI, and I don't think we want
> that. I would have expected (perhaps naively) to see explicit
> locations supported using a more natural python convention, such as
> using PyArg_ParseTupleAndKeywords.

My original implementation was that. I had function="foo" etc as
parameters to the constructor. The problem is with the -line
parameters and relative parameters. So line=+3 won't work in the
Python parameter sense. So it would have to be line="+3" in the
constructor. If keywords are all strings, I'm not sure I see the point
of parsing them as keywords when you can just specify the whole string
(i.e.  gdb.Breakpoint("-source=foo.c -line=28"). This is what we do,
more less, with the current constructor: IE

foo = gdb.Breakpoint("bar.c:23")
or
foo = gdb.Breakpoint("functionName").

So this patch allows the addition of explicit location parsing in much
the same vein as we handle regular breakpoints. (That is, with a
CLI-like interface). The gdb.Breakpoint class, for better or for
worse, is based pretty much on the interface to create_breakpoint. I'm
not adverse to implementing keywords; it's a little extra string
wrangling, but I'm not clear on the benefit? The gdb.Breakpoint class
has always handed over the interpretation of breakpoints to GDB using
the CLI like syntax. I can see why MI separates it out, and I take
your point well, in a machine context.

Cheers

Phil