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

["Aktemur, Baris" <TankutBaris.Aktemur@amd.com>]

AMD General

On Wednesday, October 21, 2026 3:39 PM, Six, Lancelot 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
> ---
>  gdb/testsuite/gdb.rocm/displaced-stepping.exp | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/testsuite/gdb.rocm/displaced-stepping.exp
> b/gdb/testsuite/gdb.rocm/displaced-stepping.exp
> index 2466a678f19..a72c19e5314 100644
> --- a/gdb/testsuite/gdb.rocm/displaced-stepping.exp
> +++ b/gdb/testsuite/gdb.rocm/displaced-stepping.exp
> @@ -23,7 +23,8 @@ require allow_hip_tests
>
>  # Since GDB doesn't yet understand DWARF expressions generated by the HIP
>  # compiler, purposefully generate the binary without debug info.
> -if {[build_executable "failed to prepare" $testfile $srcfile {hip}]} {
> +if {[build_executable "failed to prepare" $testfile $srcfile \
> +     {hip "additional_flags=-fno-unwind-tables -fno-asynchronous-unwind-tables"}]} {

Looks good to me.  I tested on gfx1201.  Maybe worth noting that "nodebug" does not
suffice.

-Baris

Reviewed-By: Tankut Baris Aktemur <TankutBaris.Aktemur@amd.com>