[v2,0/5] Modernize frame unwinders and add disable feature

  This patch series started with me trying to make it easier to test GDB's
ability to unwind using CFI data, to improve a previous patch I sent to
the list.

The first patch is just a minor change, storing frame unwinders in a
vector instead of through an unwinder table accessible using the
registry system. This isn't required (like I originally thought it was),
but it does make the whole system more readable in my opinion.

Patch 3 has the real meat of the modernization, making GDB use
polymorphism to handle frame unwinders. This is slightly slower than
using function pointers, but much more readable in my opinion.

As for the unwinder classes, they were chosen somewhat arbitrarily,
mostly based on where I found an unwinder and its name. I almost expect
some unwinders to be mis-categorized, but that should be easy to fix.

The changes up to patch 3 have been tested with a try-branch, no
regressions as far as I could see.

Changes for v2:
* Added back the test that checks if GDB can handle a mix of CUs with
  and without debuginfo in a single backtrace.
* Fixed all the nitpicks for style.
* Removed FRAME_UNWIND_ prefix when talking about classes
* Thoroughly changed the documentation, to be more readable

Guinevere Larsen (5):
  gdb: make gdbarch store a vector of frame unwinders
  gdb: add "unwinder class" to frame unwinders
  gdb: Migrate frame unwinders to use C++ classes
  gdb: introduce ability to disable frame unwinders
  gdb/testsuite: Test for a backtrace through object without debuginfo

 gdb/NEWS                                      |   7 +
 gdb/aarch64-tdep.c                            |  12 +-
 gdb/alpha-mdebug-tdep.c                       |   6 +-
 gdb/alpha-tdep.c                              |  12 +-
 gdb/amd64-obsd-tdep.c                         |   6 +-
 gdb/amd64-tdep.c                              |  24 +-
 gdb/amd64-windows-tdep.c                      |   6 +-
 gdb/amdgpu-tdep.c                             |   7 +-
 gdb/arc-tdep.c                                |  10 +-
 gdb/arch-utils.c                              |   8 +
 gdb/arm-tdep.c                                |  29 +-
 gdb/avr-tdep.c                                |   5 +-
 gdb/bfin-tdep.c                               |   6 +-
 gdb/bpf-tdep.c                                |   6 +-
 gdb/cris-tdep.c                               |  12 +-
 gdb/csky-tdep.c                               |  10 +-
 gdb/doc/gdb.texinfo                           |  24 ++
 gdb/dummy-frame.c                             |   8 +-
 gdb/dummy-frame.h                             |   2 +-
 gdb/dwarf2/frame-tailcall.c                   |   6 +-
 gdb/dwarf2/frame-tailcall.h                   |   2 +-
 gdb/dwarf2/frame.c                            |  16 +-
 gdb/frame-unwind.c                            | 335 ++++++++++++++----
 gdb/frame-unwind.h                            | 178 +++++++++-
 gdb/frame.c                                   |  28 +-
 gdb/frv-linux-tdep.c                          |   6 +-
 gdb/frv-tdep.c                                |   5 +-
 gdb/ft32-tdep.c                               |   6 +-
 gdb/gdbarch.c                                 |   3 +
 gdb/gdbarch.h                                 |   5 +
 gdb/gdbarch.py                                |   3 +
 gdb/h8300-tdep.c                              |   5 +-
 gdb/hppa-linux-tdep.c                         |   5 +-
 gdb/hppa-tdep.c                               |  17 +-
 gdb/i386-obsd-tdep.c                          |   5 +-
 gdb/i386-tdep.c                               |  30 +-
 gdb/ia64-tdep.c                               |  24 +-
 gdb/inline-frame.c                            |   5 +-
 gdb/inline-frame.h                            |   2 +-
 gdb/iq2000-tdep.c                             |   5 +-
 gdb/jit.c                                     |   6 +-
 gdb/lm32-tdep.c                               |   5 +-
 gdb/loongarch-tdep.c                          |   7 +-
 gdb/m32c-tdep.c                               |   5 +-
 gdb/m32r-linux-tdep.c                         |   5 +-
 gdb/m32r-tdep.c                               |   5 +-
 gdb/m68hc11-tdep.c                            |   5 +-
 gdb/m68k-linux-tdep.c                         |   6 +-
 gdb/m68k-tdep.c                               |   6 +-
 gdb/mep-tdep.c                                |   5 +-
 gdb/microblaze-tdep.c                         |   6 +-
 gdb/mips-sde-tdep.c                           |   6 +-
 gdb/mips-tdep.c                               |  24 +-
 gdb/mn10300-tdep.c                            |   5 +-
 gdb/moxie-tdep.c                              |   5 +-
 gdb/msp430-tdep.c                             |   5 +-
 gdb/nds32-tdep.c                              |  14 +-
 gdb/nios2-tdep.c                              |  12 +-
 gdb/or1k-tdep.c                               |   7 +-
 gdb/ppc-fbsd-tdep.c                           |   5 +-
 gdb/ppc-obsd-tdep.c                           |   5 +-
 gdb/python/py-unwind.c                        |  50 ++-
 gdb/record-btrace.c                           |  12 +-
 gdb/record.h                                  |   4 +-
 gdb/riscv-tdep.c                              |   8 +-
 gdb/rl78-tdep.c                               |   6 +-
 gdb/rs6000-aix-tdep.c                         |   5 +-
 gdb/rs6000-tdep.c                             |  12 +-
 gdb/rx-tdep.c                                 |  10 +-
 gdb/s12z-tdep.c                               |   7 +-
 gdb/s390-linux-tdep.c                         |   5 +-
 gdb/s390-tdep.c                               |  10 +-
 gdb/sentinel-frame.c                          |   8 +-
 gdb/sentinel-frame.h                          |   2 +-
 gdb/sh-tdep.c                                 |  11 +-
 gdb/sparc-netbsd-tdep.c                       |   6 +-
 gdb/sparc-obsd-tdep.c                         |   6 +-
 gdb/sparc-sol2-tdep.c                         |   6 +-
 gdb/sparc-tdep.c                              |   6 +-
 gdb/sparc64-fbsd-tdep.c                       |   6 +-
 gdb/sparc64-netbsd-tdep.c                     |   6 +-
 gdb/sparc64-obsd-tdep.c                       |  12 +-
 gdb/sparc64-sol2-tdep.c                       |   6 +-
 gdb/sparc64-tdep.c                            |   6 +-
 .../backtrace-through-cu-nodebug-caller.c     |  28 ++
 .../backtrace-through-cu-nodebug-main.c       |  32 ++
 .../gdb.base/backtrace-through-cu-nodebug.exp |  87 +++++
 gdb/testsuite/gdb.base/frame-unwind-disable.c |  21 ++
 .../gdb.base/frame-unwind-disable.exp         | 114 ++++++
 gdb/tic6x-tdep.c                              |  12 +-
 gdb/tilegx-tdep.c                             |   5 +-
 gdb/tramp-frame.c                             |  56 ++-
 gdb/v850-tdep.c                               |   5 +-
 gdb/vax-tdep.c                                |   6 +-
 gdb/windows-tdep.c                            |  33 +-
 gdb/windows-tdep.h                            |  16 +-
 gdb/xstormy16-tdep.c                          |   5 +-
 gdb/xtensa-tdep.c                             |   7 +-
 gdb/z80-tdep.c                                |   7 +-
 99 files changed, 1240 insertions(+), 444 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/backtrace-through-cu-nodebug-caller.c
 create mode 100644 gdb/testsuite/gdb.base/backtrace-through-cu-nodebug-main.c
 create mode 100644 gdb/testsuite/gdb.base/backtrace-through-cu-nodebug.exp
 create mode 100644 gdb/testsuite/gdb.base/frame-unwind-disable.c
 create mode 100644 gdb/testsuite/gdb.base/frame-unwind-disable.exp
  

For anyone reviewing this, I'm aware of the arm regressions (thanks 
again, linaro CI). I'm looking into them, but other reviews are still 
welcome!