[PATCH 0/2] gdb/alpha: Add target description support and fpcr flags

[Yodel Eldar <yodel.eldar@gmail.com>]

Please note that the second patch depends on the first.

I initially wrote the target description for use in another project, but
when I connected GDB to that project's gdbstub during testing, GDB
emitted a warning about rejecting the target description (because it
does not support them for Alpha); so, I firstly submit it here (along
with some plumbing) and would like to assign the copyright to the FSF
for the first time.

Target description support will allow Alpha target users to easily
specify features of their system at hand that GDB does not have itself;
e.g., according to [1] (see below), Alpha 21264 (EV6) does not implement
the DNOD flag (bit 47) of the fpcr, contrary to other versions; users
can easily inform GDB of this difference by dynamically feeding it their
desired target description instead of modifying code for recompilation.

Furthermore, Alpha's target-dependent code no longer needs helper
functions to get the name or type of a requested register as seen with
the removal of alpha_register_name and alpha_register_type in patch one;
this separation of concerns improves maintainability over the long run.

Converting fpcr from an int64 to a flags type with just a few lines of
XML in the second patch demonstrates the power of the target description
framework in the convenience that it affords. As a control register, the
flags type suits the fpcr better than an int64, because it is a bitfield
of flags; admittedly, sixteen flags are a lot, but the fpcr does not
appear in "info regs" unless the command is invoked with "float" or
"all," and its flags will not appear in the output unless they are set.

Lastly, this is my first submission to GDB, and I want to take this
opportunity to thank all of the incredible folks who have contributed to
this beloved project that has helped me better understand what occurs
under the hood of programs over the years. Thank you! I welcome any and
all suggestions for improvement.

[1] https://www.star.bnl.gov/public/daq/HARDWARE/21264_data_sheet.pdf

Yodel Eldar (2):
  gdb/alpha: Add target description support
  gdb/alpha: Redefine fpcr with fpcr_flags type

 gdb/NEWS                    |   2 +
 gdb/alpha-tdep.c            |  87 ++++++++++++-----------
 gdb/doc/gdb.texinfo         |  42 +++++++++++
 gdb/features/Makefile       |   1 +
 gdb/features/alpha-core.xml | 136 ++++++++++++++++++++++++++++++++++++
 gdb/features/alpha.c        | 111 +++++++++++++++++++++++++++++
 gdb/features/alpha.xml      |  11 +++
 7 files changed, 351 insertions(+), 39 deletions(-)
 create mode 100644 gdb/features/alpha-core.xml
 create mode 100644 gdb/features/alpha.c
 create mode 100644 gdb/features/alpha.xml

-- 
2.49.0