RE: [PATCH] gdb/testsuite: Fix gdb.rocm/displaced-stepping.exp

["Six, Lancelot" <Lancelot.Six@amd.com>]

AMD General

> -----Original Message-----
> From: Simon Marchi <simark@simark.ca>
> Sent: 21 October 2026 15:22
> To: Six, Lancelot <Lancelot.Six@amd.com>; gdb-patches@sourceware.org
> Cc: Aktemur, Baris <TankutBaris.Aktemur@amd.com>; Machado, Luis
> <Luis.Machado@amd.com>
> Subject: Re: [PATCH] gdb/testsuite: Fix gdb.rocm/displaced-stepping.exp
>
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
>
>
> On 10/21/26 9:39 AM, Lancelot SIX wrote:
> > The gdb.rocm/displaced-stepping.exp testcase currently fails with:
> >
> >   with debug displaced on -- stepi
> >   Unhandled dwarf expression opcode 0xe9
> >   (gdb) FAIL: gdb.rocm/displaced-stepping.exp: with debug displaced on --
> stepi
> >
> > This is because when doing the stepi, GDB computes the current frame ID
> > in set_step_info.  This will go and evaluate the CFA for the current
> > frame, which reads AMDGPU debug info, which is not supported by GDB
> > currently.
> >
> > Current AMDGPU DWARF requires changes expected to be available in the
> > future DWARF-6 standard (address space support), as well as llvm private
> > opcodes (DW_OP_LLVM_user DW_OP_LLVM_form_aspace_address):
> >
> >     $ llvm-dwarfdump --debug-frame displaced-stepping.0.hip-amdgcn-amd-
> amdhsa--gfx1031
> >     [...]
> >     00000014 00000018 00000018 FDE cie=00000000
> pc=00001a00...00001b64
> >       Format:       DWARF32
> >       DW_CFA_def_cfa_expression: DW_OP_lit0, DW_OP_lit6,
> DW_OP_LLVM_user DW_OP_LLVM_form_aspace_address
> >
> > At this point, there is no way to support this in GDB, so instead this
> > patch proposes to fix the failure by instructing the compiler to not
> > produce any unwind table.
> >
> > Tested on x86_64-linux + AMDGPU-gfx1031.
> >
> > Change-Id: I2e62270f39c9e96324ae01d401bafb46cfff596c
>
> I suppose something changed in the compiler since the test was merged,
> since it used to pass.  Did it not emit those tables before?
>

Indeed.  I have not tracked when the compiler started to emit those by default. As you say, this used to pass.

Thanks for the review.

> Approved-By: Simon Marchi <simon.marchi@efficios.com>
>
> Simon