[DTrace-devel] [PATCH] Add reloc support for the add immediate instruction

[Eugene Loh]

Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
but any tests?

On 3/9/22 4:42 PM, Kris Van Hees via DTrace-devel wrote:
> This patch also reworks a somewhat ugly compound conditional statement
> into a switch statement.
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
>   libdtrace/dt_as.c | 35 +++++++++++++++++++----------------
>   1 file changed, 19 insertions(+), 16 deletions(-)
>
> diff --git a/libdtrace/dt_as.c b/libdtrace/dt_as.c
> index 8ae7bd96..a634b855 100644
> --- a/libdtrace/dt_as.c
> +++ b/libdtrace/dt_as.c
> @@ -279,6 +279,7 @@ dt_as(dt_pcb_t *pcb)
>   		case BPF_ST | BPF_MEM | BPF_W:		/* stw */
>   		case BPF_ST | BPF_MEM | BPF_DW:		/* stdw */
>   		case BPF_ALU64 | BPF_MOV | BPF_K:	/* mov */
> +		case BPF_ALU64 | BPF_ADD | BPF_K:	/* add */
>   			if (idp->di_flags & DT_IDFLG_BPF)
>   				brel++;
>   			else
> @@ -486,27 +487,29 @@ fail:
>   			if (!nodef)
>   				dt_as_undef(idp, i);
>   
> -			if (dip->di_instr.code ==
> -					(BPF_LD | BPF_IMM | BPF_DW))
> -				rp->dofr_type = R_BPF_64_64;
> -			else if (dip->di_instr.code ==
> -					(BPF_ST | BPF_MEM | BPF_W))
> -				rp->dofr_type = R_BPF_64_32;
> -			else if (dip->di_instr.code ==
> -					(BPF_ST | BPF_MEM | BPF_DW))
> -				rp->dofr_type = R_BPF_64_32;
> -			else if (dip->di_instr.code ==
> -					(BPF_ALU64 | BPF_MOV | BPF_K))
> -				rp->dofr_type = R_BPF_64_32;
> -			else if (dip->di_instr.code ==
> -					(BPF_JMP | BPF_CALL) &&
> -				 dip->di_instr.src_reg == BPF_PSEUDO_CALL)
> +			switch (dip->di_instr.code) {
> +			case BPF_ST | BPF_MEM | BPF_W:		/* stw */
> +			case BPF_ST | BPF_MEM | BPF_DW:		/* stdw */
> +			case BPF_ALU64 | BPF_MOV | BPF_K:	/* mov */
> +			case BPF_ALU64 | BPF_ADD | BPF_K:	/* add */
>   				rp->dofr_type = R_BPF_64_32;
> -			else
> +				break;
> +			case BPF_LD | BPF_IMM | BPF_DW:		/* lddw */
> +				rp->dofr_type = R_BPF_64_64;
> +				break;
> +			case BPF_JMP | BPF_CALL:	/* call */
> +				if (dip->di_instr.src_reg == BPF_PSEUDO_CALL) {
> +					rp->dofr_type = R_BPF_64_32;
> +					break;
> +				}
> +
> +				/* fall-through */
> +			default:
>   				xyerror(D_UNKNOWN, "unexpected asm relocation "
>   					"for opcode 0x%x (@%d, %s)\n",
>   					dip->di_instr.code, i - 1,
>   					idp->di_name);
> +			}
>   
>   			soff = dt_strtab_insert(dtp->dt_ccstab, idp->di_name);
>