Re: [PATCH v2] gdb: LoongArch: Change LOONGARCH_FIRST_FP_REGNUM to 35

[Hui Li <lihui@loongson.cn>]

On 2024/2/27 上午9:18, Hui Li wrote:
> There is an assertion error "gdb_assert (n < tdesc->reg_defs.size ())"
> in find_register_by_number() when gdb connects to gdbserver, this
> is because the value of LOONGARCH_LINUX_NUM_GREGSET (45, which contains
> 10 reserved regs) is different with the number of regs (35, which not
> contains 10 reserved regs) in file gdb/features/loongarch/base64.xml.
> Add a new macro LOONGARCH_USED_NUM_GREGSET which is defined as 35 to
> keep consistent with the gdb/features/loongarch/base64.xml, and then
> define LOONGARCH_FIRST_FP_REGNUM as LOONGARCH_USED_NUM_GREGSET so that
> all the reg numbers in regcache are consistent with tdesc reg numbers.
> 
> without this patch:
> 
> Execute on the target machine:
> 
>    $ gdbserver 192.168.1.123:5678 ./test
> 
> Execute on the host machine:
> 
>    $ gdb ./test
>    (gdb) target remote 192.168.1.123:5678
> 
> Output on the target machine:
> 
>    Process ./test created; pid = 67683
>    Listening on port 5678
>    Remote debugging from host 192.168.1.136, port 6789
>    gdbserver/regcache.cc:205: A problem internal to GDBserver has been detected.
>    find_register_by_number: Assertion 'n < tdesc->reg_defs.size ()' failed.
> 
> Output on the host machine:
> 
>    Remote debugging using 192.168.1.123:5678
>    Remote connection closed
> 
> Signed-off-by: Hui Li <lihui@loongson.cn>
> ---
>   gdb/arch/loongarch.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/arch/loongarch.h b/gdb/arch/loongarch.h
> index 4b7ab054ea0..7056d506bf4 100644
> --- a/gdb/arch/loongarch.h
> +++ b/gdb/arch/loongarch.h
> @@ -33,10 +33,11 @@ enum loongarch_regnum
>     LOONGARCH_ORIG_A0_REGNUM = 32,	/* Syscall's original arg0.  */
>     LOONGARCH_PC_REGNUM = 33,		/* Program Counter.  */
>     LOONGARCH_BADV_REGNUM = 34,		/* Bad Vaddr for Addressing Exception.  */
> +  LOONGARCH_USED_NUM_GREGSET = 35,	/* 32 GPR, ORIG_A0, PC, BADV.  */
>     LOONGARCH_LINUX_NUM_GREGSET = 45,	/* 32 GPR, ORIG_A0, PC, BADV, RESERVED 10.  */
>     LOONGARCH_ARG_REGNUM = 8,            /* r4-r11: general-purpose argument registers.
>   					  f0-f7: floating-point argument registers.  */
> -  LOONGARCH_FIRST_FP_REGNUM = LOONGARCH_LINUX_NUM_GREGSET,
> +  LOONGARCH_FIRST_FP_REGNUM = LOONGARCH_USED_NUM_GREGSET,
>     LOONGARCH_LINUX_NUM_FPREGSET = 32,
>     LOONGARCH_FIRST_FCC_REGNUM = LOONGARCH_FIRST_FP_REGNUM + LOONGARCH_LINUX_NUM_FPREGSET,
>     LOONGARCH_LINUX_NUM_FCC = 8,
> 

Hi John,

Are you ok for this version?

Thanks,
Hui