Re: [PATCH v3] gdb: Add python support for demangling register unwind values

[Eli Zaretskii <eliz@gnu.org>]

> From: Craig Blackmore <craig.blackmore@embecosm.com>
> Cc: aburgess@redhat.com,
> 	eliz@gnu.org,
> 	Craig Blackmore <craig.blackmore@embecosm.com>
> Date: Thu, 30 Apr 2026 16:31:55 +0100
> 
>  gdb/NEWS                                      |  20 +++
>  gdb/doc/python.texi                           |  95 ++++++++++
>  gdb/extension-priv.h                          |   8 +
>  gdb/extension.c                               |  35 ++++
>  gdb/extension.h                               |   6 +
>  gdb/frame.c                                   |   9 +
>  gdb/guile/guile.c                             |   2 +
>  gdb/python/lib/gdb/__init__.py                |  21 +++
>  gdb/python/lib/gdb/unwinder.py                |  89 ++++++++-
>  gdb/python/py-registers.c                     |   2 +-
>  gdb/python/py-unwind.c                        | 169 ++++++++++++++++++
>  gdb/python/py-value.c                         |  21 +++
>  gdb/python/python-internal.h                  |   3 +
>  gdb/python/python.c                           |   4 +-
>  .../gdb.python/py-unwind-transformer-error.py |  33 ++++
>  .../gdb.python/py-unwind-transformer.c        |  80 +++++++++
>  .../gdb.python/py-unwind-transformer.exp      | 115 ++++++++++++
>  .../gdb.python/py-unwind-transformer.py       |  48 +++++
>  gdb/testsuite/gdb.python/py-value.exp         |   8 +
>  19 files changed, 765 insertions(+), 3 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.python/py-unwind-transformer-error.py
>  create mode 100644 gdb/testsuite/gdb.python/py-unwind-transformer.c
>  create mode 100644 gdb/testsuite/gdb.python/py-unwind-transformer.exp
>  create mode 100644 gdb/testsuite/gdb.python/py-unwind-transformer.py

Thanks.

> diff --git a/gdb/NEWS b/gdb/NEWS
> index e233906153a..c1dc008280e 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -457,6 +457,26 @@ info threads [-gid] [-stopped] [-running] [ID]...
>       unavailability like gdb.Value.is_optimized_out checks for
>       optimized out values.
>  
> +  ** New constants gdb.NOT_LVAL, gdb.LVAL_REGISTER and gdb.LVAL_MEMORY
> +     to represent the lval_type of a value.
> +
> +  ** New read-only attribute gdb.Value.lval_type which indicates the
> +     lval_type of the value.  Currently supports not_lval, lval_register
> +     and lval_memory.  Any other type is mapped to not_lval.  Additional
> +     types may be supported in future.
> +
> +  ** Added gdb.unwinder.UnwindRegisterValueTransformer.  This is the
> +     base class for transformers which provide methods for transforming
> +     unwind register values.  Currently one such method, demangle, is
> +     supported, which is called after obtaining a register value from an
> +     unwinder and allows that value to be demangled before being used by
> +     GDB.
> +
> +  ** New function gdb.unwinder.register_unwind_register_value_transformer
> +     that can register an instance of a sub-class of
> +     gdb.unwinder.UnwindRegisterValueTransformer as a transformer for
> +     unwind register values.
> +
>  * Guile API

This part is okay.

> +@defvar Value.lval_type
> +The lval_type of this @code{gdb.Value}.  The value of this attribute can

What is "lval_type"?  If it's a known term in Python programming,
please give it the @code markup.  Alternatively, replace with just
"type", a common word.

> +Additional lval_types may be added in future.

Same here.

> +Currently, only one transformer can be registered at any one time and it
> +is registered globally.  Attempting to register more than one
> +transformer or to a different locus will raise an exception.
> +Registering more than one transformer or to different loci may be
> +supported in future.

I'd remove the last sentence, it isn't useful in the manual.

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