RE: [PATCHv4 00/10] x86/Linux Target Description Changes

["Willgerodt, Felix" <felix.willgerodt@intel.com>]

> -----Original Message-----
> From: Andrew Burgess <aburgess@redhat.com>
> Sent: Freitag, 5. April 2024 14:33
> To: gdb-patches@sourceware.org
> Cc: Andrew Burgess <aburgess@redhat.com>
> Subject: [PATCHv4 00/10] x86/Linux Target Description Changes
> 
> In v4:
> 
>   - I tried merging V3, but it turned out I broke pretty much
>     everything that wasn't x86 based when configured with
>     --enable-targets=all,
> 
>   - The problem was a failure to correctly split the shared code
>     between the gdb/arch/ and gdb/nat/ directories, as a consequence,
>     code which is needed on a non x86 based host to support x86 based
>     targets wasn't available to the compilation, and the build failed,
> 
>   - In V4 I've gone through every patch and resplit the code in a way
>     which I now believe is correct, I've done the following tests:
> 
>     + On a non x86 host I've built GDB to support only the current
>     host as a target, to support all targets, and to support x86-64
>     and i386 linux targets,
> 
>     + On an i386 virtual machine I built GDB only for the host as a
>     target, and for all targets.  I regression tested the all targets
>     build for unix, native-gdbserver, and native-extended-gdbserver,
> 
>     + On an x86-64 machine I've built GDB for only the current host as
>     a target, and for all targets.  I regression tested the all targets
>     build for unix, native-gdbserver, and native-extended-gdbserver.
> 
>   - Only patches 6, 8, and 10 require significant review.  All of the
>     other patches are pretty trivial (though reviews always welcome).
> 
>   - I think there's more improvements that can be made to the x86
>     target description creation/lookup/caching.  This series only
>     changes the Linux lookup, and we still cache i386/amd64/x32
>     separately.
> 
>     In the future I think we can merge all x86 target description
>     caching into a single data structure, this would be for all OS
>     variants and all ABI variants.
> 
>     Though making that "grand unification" will certainly require some
>     of the code in this series to change, I think the bulk of it will
>     remain, and trying to do everything in one series is just going to
>     result in an even larger series.  I'd prefer to get these first
>     patches merged, then come back to build on this work once this is
>     merged and we know there's no problems with it.
> 
> In v3:
> 
>   - Rebased.  Nasty merge conflict with 4bb20a6244b7091 which I think
>     I've resolved, but am unable to test.  Reposting so the author of
>     that other commit can validate.
> 
>   - Initial testing looks good.  Full tests are still running.
> 
> In v2:
> 
>   - Rebase to current upstream/master, no merge conflicts,
> 
>   - Retested.
> 
> ---
> 
> Andrew Burgess (10):
>   gdbserver/ipa/x86: remove unneeded declarations
>   gdbserver: convert have_ptrace_getregset to a tribool
>   gdb/x86: move reading of cs and ds state into gdb/nat directory
>   gdbserver/x86: move no-xml code earlier in x86_linux_read_description
>   gdb/gdbserver: share I386_LINUX_XSAVE_XCR0_OFFSET definition
>   gdb/gdbserver: share some code relating to target description creation
>   gdb/arch: assert that X86_XSTATE_MPX is not set for x32
>   gdbserver: update target description creation for x86/linux
>   gdb: move xcr0 == 0 check into i386_linux_core_read_description
>   gdb/gdbserver: share x86/linux tdesc caching
> 
>  gdb/Makefile.in                     |   8 +
>  gdb/amd64-linux-tdep.c              |  32 +---
>  gdb/amd64-linux-tdep.h              |   6 -
>  gdb/arch/amd64-linux-tdesc.c        |  61 +++++++
>  gdb/arch/amd64-linux-tdesc.h        |  30 ++++
>  gdb/arch/amd64.c                    |   8 +-
>  gdb/arch/i386-linux-tdesc.c         |  51 ++++++
>  gdb/arch/i386-linux-tdesc.h         |  29 ++++
>  gdb/arch/x86-linux-tdesc-features.c | 247 ++++++++++++++++++++++++++++
>  gdb/arch/x86-linux-tdesc-features.h |  62 +++++++
>  gdb/arch/x86-linux-tdesc.h          |  37 +++++
>  gdb/configure.nat                   |   8 +-
>  gdb/configure.tgt                   |  11 +-
>  gdb/i386-linux-tdep.c               |  42 ++---
>  gdb/i386-linux-tdep.h               |  23 ---
>  gdb/nat/x86-linux-tdesc.c           | 120 ++++++++++++++
>  gdb/nat/x86-linux-tdesc.h           |  60 +++++++
>  gdb/nat/x86-linux.c                 |  47 ++++++
>  gdb/nat/x86-linux.h                 |  28 ++++
>  gdb/x86-linux-nat.c                 | 123 ++------------
>  gdbserver/configure.srv             |  11 ++
>  gdbserver/linux-amd64-ipa.cc        |  50 ++----
>  gdbserver/linux-arm-low.cc          |   6 +-
>  gdbserver/linux-i386-ipa.cc         |  26 +--
>  gdbserver/linux-low.cc              |   2 +-
>  gdbserver/linux-low.h               |   2 +-
>  gdbserver/linux-x86-low.cc          | 192 +++++++--------------
>  gdbserver/linux-x86-tdesc.cc        | 142 +---------------
>  gdbserver/linux-x86-tdesc.h         |  56 -------
>  gdbsupport/x86-xstate.h             |  20 +++
>  30 files changed, 949 insertions(+), 591 deletions(-)
>  create mode 100644 gdb/arch/amd64-linux-tdesc.c
>  create mode 100644 gdb/arch/amd64-linux-tdesc.h
>  create mode 100644 gdb/arch/i386-linux-tdesc.c
>  create mode 100644 gdb/arch/i386-linux-tdesc.h
>  create mode 100644 gdb/arch/x86-linux-tdesc-features.c
>  create mode 100644 gdb/arch/x86-linux-tdesc-features.h
>  create mode 100644 gdb/arch/x86-linux-tdesc.h
>  create mode 100644 gdb/nat/x86-linux-tdesc.c
>  create mode 100644 gdb/nat/x86-linux-tdesc.h
>  delete mode 100644 gdbserver/linux-x86-tdesc.h
> 
> 
> base-commit: 16810e455feb26ef826a3ed876d6d7e6d24818b0
> --
> 2.25.4


Hi Andrew,

Thanks for doing this, I like what this does.
I am still in the middle of reviewing this. Though in first testing I saw
that I can't build a 32-bit gdbserver on Ubuntu 22.04.
I am building like this: 

export CFLAGS="-g -O0 -m32"
export CXXFLAGS="${CFLAGS} -m32"
export LDFLAGS="-m32"

$src/gdb/configure \                                                            
     --build="x86_64-linux-gnu" \                                                
     --host="i686-linux-gnu" \                                                   
     --disable-gdb

make -s -j$(nproc)  all-gdbserver

Not sure if there is an easier way of doing this, but this works for master.
With your series I see this:

  CXX    nat/x86-linux-tdesc.o
/gdb/gdbserver/../gdb/nat/x86-linux-tdesc.c: In function ?const target_desc*
x86_linux_tdesc_for_tid(int, tribool*, gdb::function_view<void(long long unsigned int)>, const char*, uint64_t*)?:
/gdb/gdbserver/../gdb/nat/x86-linux-tdesc.c:54:7: error: ?have_ptrace_getfpxregs? was not declared in this scope;
did you mean ?have_ptrace_getregset??
   54 |   if (have_ptrace_getfpxregs == -1)
      |       ^~~~~~~~~~~~~~~~~~~~~~
      |       have_ptrace_getregset
/gdb/gdbserver/../gdb/nat/x86-linux-tdesc.c:56:7: error: ?elf_fpxregset_t? was not declared in this scope
   56 |       elf_fpxregset_t fpxregs;
      |       ^~~~~~~~~~~~~~~
In file included from /gdb/gdbserver/../gdb/nat/x86-linux-tdesc.c:29:
/gdb/gdbserver/../gdb/nat/x86-linux-tdesc.c:58:53: error: ?fpxregs? was not declared in this scope
   58 |       if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
      |                                                     ^~~~~~~
/gdb/gdbserver/../gdb/nat/gdb_ptrace.h:142:57: note: in definition of macro ?ptrace?
  142 |          ptrace ((PTRACE_TYPE_ARG1) request, pid, addr, data)
      |                                                         ^~~~
make[1]: *** [Makefile:577: nat/x86-linux-tdesc.o] Error 1
make: *** [Makefile:13074: install-gdbserver] Error 2

I didn't investigate further yet, sorry.

Regards,
Felix
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