Re: [PATCH] Add Frame.read_register to Python API

[Alexander Smundak <asmundak at google dot com>]

Ping

On Wed, Jun 18, 2014 at 10:18 AM, Alexander Smundak <asmundak@google.com> wrote:
> Ping.
>
> On Wed, Jun 11, 2014 at 4:52 PM, Alexander Smundak <asmundak@google.com> wrote:
>>> Alexander>      def __init__(self, fobj):
>>> Alexander>          super(InlinedFrameDecorator, self).__init__(fobj)
>>> Alexander> +        self.fobj = fobj
>>>
>>> Alexander>      def function(self):
>>> Alexander> -        frame = fobj.inferior_frame()
>>> Alexander> +        frame = self.fobj.inferior_frame()
>>> Alexander>          name = str(frame.name())
>>>
>>> I think this is a nice fix but it seems unrelated to the patch at hand.
>>>
>>> Alexander>  @defun Frame.find_sal ()
>>> Alexander> -Return the frame's symtab and line object.
>>> Alexander> +Return the frame's @code{gdb.Symtab_and_line} object.
>>>
>>> Likewise.
>>
>> Should I mail these two as a single patch or as two separate patches?
>>
>>> Alexander> +      FRAPY_REQUIRE_VALID (self, frame);
>>> Alexander> +      if (!PyArg_ParseTuple (args, "i", &regnum))
>>> Alexander> +    {
>>> Alexander> +      const char *regnum_str;
>>> Alexander> +      PyErr_Clear();  /* Clear PyArg_ParseTuple failure above.  */
>>> Alexander> +      if (PyArg_ParseTuple (args, "s", &regnum_str))
>>> Alexander> +        {
>>> Alexander> +          regnum = user_reg_map_name_to_regnum (get_frame_arch (frame),
>>> Alexander> +                                                regnum_str,
>>> Alexander> +                                                strlen (regnum_str));
>>> Alexander> +        }
>>> Alexander> +    }
>>>
>>> I tend to think this would be clearer if the arguments were only parsed
>>> once and then explicit type checks were applied to the resulting object.
>>
>> Did that, and then started doubting whether it is really necessary to read
>> a register by its (very arch-specific) number. The new version supports
>> reading the register by the name. Another change is that it now throws
>> an exception if the name is wrong.
>>
>>> Alexander> +# On x86-64, PC is register 16.
>>> Alexander> +gdb_test "python print ('result = %s' % ((f0.architecture().name() != 'i386:x86-64') or f0.read_register('pc') == f0.read_register(16)))" \
>>> Alexander> +  "True" \
>>> Alexander> +  "test Frame.read_register(regnum)"
>>>
>>> A test that is arch-specific needs to be conditionalized somehow.
>> IMHO it's borderline arch-specific -- it is runnable on any platform,
>> although it will not be testing much on any but x86-64. There hasn't
>> been any arch-specific tests for Python so far, so I am not sure what to do.
>>
>> Here's the new version (style violations have been addressed, too):
>>
>> The ability to read registers is needed to use Frame Filter API to
>> display the frames created by JIT compilers.
>>
>> gdb/Changelog
>> 2014-06-11  Sasha Smundak  <asmundak@google.com>
>>
>> * python/py-frame.c (frapy_read_register): New function.
>>
>> 2014-06-11  Sasha Smundak  <asmundak@google.com>
>>
>> * python.texi (Frames in Python): Add read_register description.
>>
>> 2014-06-11  Sasha Smundak  <asmundak@google.com>
>>
>> * gdb.python/py-frame.exp: Test Frame.read_register.