[DTrace-devel] [PATCH REVIEW 1/6] cg: fix calls to rand

[Kris Van Hees]

Reviewed-by: Kris Van Hees (kris.van.hees at oracle.com>

... and I added it to the 'dev' branch already.

On Thu, Sep 09, 2021 at 12:13:40PM +0100, Nick Alcock wrote:
> For many types of identifier, a di_id of 0 means "undefined".  But for
> subrs, di_id 0 is DIF_SUBR_RAND, a valid (albeit currently
> unimplemented) subr.
> 
> Fixes several assertion failures running the testsute.
> 
> Signed-off-by: Nick Alcock <nick.alcock at oracle.com>
> ---
>  libdtrace/dt_cg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> I *think* it's safe to eliminate the 0: for some types of identifier,
> 0 means "unset", but for DIF_SUBRs, it cannot possibly mean that
> because 0 has another meaning already.  I audited all assignments
> to 0 and all checks of di_id for zeroness and none seemed to be
> something that could ever be done to subrs, so I think we're safe.
> 
> diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
> index 43ed2351d51c..467317de1a66 100644
> --- a/libdtrace/dt_cg.c
> +++ b/libdtrace/dt_cg.c
> @@ -3186,7 +3186,7 @@ dt_cg_call_subr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
>  					"required)\n",
>  			dt_idkind_name(idp->di_kind), idp->di_name);
>  
> -	assert(idp->di_id > 0 && idp->di_id <= DIF_SUBR_MAX);
> +	assert(idp->di_id <= DIF_SUBR_MAX);
>  
>  	fun = _dt_cg_subr[idp->di_id];
>  	if (fun == NULL)
> -- 
> 2.33.0.256.gb827f06fa9
> 
> 
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