Re: [PATCH 4/5] gdb/python: rework how the disassembler API reads the result object

Eli Zaretskii via Gdb-patches
2023-04-04T11:37:58Z

> Cc: Andrew Burgess <aburgess@redhat.com>
> Date: Tue, 4 Apr 2023 09:21:06 +0100
> From: Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org>
>
> This commit is a refactor ahead of the next change which will make
> disassembler styling available through the Python API.
>
> Unfortunately, in order to make the styling support available, I think
> the easiest solution is to make a very small change to the existing
> API.
>
> The current API relies on returning a DisassemblerResult object to
> represent each disassembled instruction. Currently GDB allows the
> DisassemblerResult class to be sub-classed, which could mean that a
> user tries to override the various attributes that exist on the
> DisassemblerResult object.
>
> This commit removes this ability, effectively making the
> DisassemblerResult class final.
>
> Though this is a change to the existing API, I'm hoping this isn't
> going to cause too many issues:
>
> - The Python disassembler API was only added in the previous release
> of GDB, so I don't expect it to be widely used yet, and
>
> - It's not clear to me why a user would need to sub-class the
> DisassemblerResult type, I allowed it in the original patch
> because at the time I couldn't see any reason to NOT allow it.
>
> Having prevented sub-classing I can now rework the tail end of the
> gdbpy_print_insn function; instead of pulling the results out of the
> DisassemblerResult object by calling back into Python, I now cast the
> Python object back to its C++ type (disasm_result_object), and access
> the fields directly from there. In later commits I will be reworking
> the disasm_result_object type in order to hold information about the
> styled disassembler output.
>
> The tests that dealt with sub-classing DisassemblerResult have been
> removed, and a new test that confirms that DisassemblerResult can't be
> sub-classed has been added.
> ---
> gdb/NEWS | 3 ++
> gdb/doc/python.texi | 2 +
> gdb/python/py-disasm.c | 54 +++++++-------------------
> gdb/testsuite/gdb.python/py-disasm.exp | 15 +++++--
> gdb/testsuite/gdb.python/py-disasm.py | 37 ------------------
> 5 files changed, 31 insertions(+), 80 deletions(-)

OK for the documentation parts. Thanks.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>