[DTrace-devel] [PATCH 5/7] cg: optional 4th arg for dt_cg_subr_arg_to_tstring() calls

[Kris Van Hees]

On Thu, Jul 27, 2023 at 07:35:10PM -0400, Eugene Loh via DTrace-devel wrote:
> Reviewed-by: Eugene Loh <eugene.loh at oracle.com>

Thanks.

> The subject line threw me for a while:  it looked like 5th and 6th args to
> dt_cg_subr_arg_to_tstring(), but now I see what you mean. Okay.
> 
> Also, ISIGN looks to me like I SIGN. Might you consider IGNOR?  Might make
> more sense especially since in this case there is nothing to "is".

Sure.

> On 7/27/23 11:30, Kris Van Hees via DTrace-devel wrote:
> > Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> > ---
> >   libdtrace/dt_cg.c | 26 +++++++++++++++++---------
> >   1 file changed, 17 insertions(+), 9 deletions(-)
> > 
> > diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
> > index 6a1413f0..e05a1f64 100644
> > --- a/libdtrace/dt_cg.c
> > +++ b/libdtrace/dt_cg.c
> > @@ -24,6 +24,7 @@
> >   #include <dt_string.h>
> >   #include <bpf_asm.h>
> > +#define DT_ISIGN	-1		/* Ignore the value */
> >   #define DT_ISIMM	0
> >   #define DT_ISREG	1
> > @@ -976,7 +977,7 @@ dt_cg_probe_error(dt_pcb_t *pcb, uint32_t fault, int illisreg, uint64_t ill)
> >   	 * one we are about to blindly reuse.
> >   	 */
> > -	if (illisreg && ill != 4)
> > +	if (illisreg == DT_ISREG && ill != 4)
> >   		emit(dlp, BPF_MOV_REG(BPF_REG_4, ill));
> >   	else
> >   		emit(dlp, BPF_MOV_IMM(BPF_REG_4, ill));
> > @@ -1213,7 +1214,7 @@ dt_cg_alloca_access_check(dt_irlist_t *dlp, dt_regset_t *drp, int reg,
> >   	emitl(dlp, lbl_base_ok,
> >   		   BPF_NOP());
> > -	if (isreg)
> > +	if (isreg == DT_ISREG)
> >   		emit(dlp, BPF_ALU64_REG(BPF_SUB, BPF_REG_0, size));
> >   	else
> >   		emit(dlp, BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, size));
> > @@ -2563,7 +2564,8 @@ dt_cg_ldsize(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type, ssize_t *ret_size)
> >   	 * rounding cte_bits up to a byte boundary and then finding the
> >   	 * nearest power of two to this value (see clp2(), above).
> >   	 */
> > -	if ((dnp->dn_flags & DT_NF_BITFIELD) &&
> > +	if (dnp &&
> > +	    (dnp->dn_flags & DT_NF_BITFIELD) &&
> >   	    ctf_type_encoding(ctfp, type, &e) != CTF_ERR)
> >   		size = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY);
> >   	else
> > @@ -4578,14 +4580,15 @@ dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   /*
> >    * Emit code to call a precompiled BPF function (named by fname)
> > - * that is of return type void and takes three arguments:
> > + * that is of return type void and takes three or four arguments:
> >    *   - a pointer to the DTrace context (dctx)
> >    *   - one input value
> >    *   - a pointer to an output tstring, allocated here
> > + *   - an optional uint32_t value
> >    */
> >   static void
> >   dt_cg_subr_arg_to_tstring(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
> > -			   const char *fname)
> > +			  const char *fname, int isreg, uint32_t val)
> >   {
> >   	dt_ident_t	*idp;
> >   	dt_node_t	*arg = dnp->dn_args;
> > @@ -4619,6 +4622,11 @@ dt_cg_subr_arg_to_tstring(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
> >   	emit(dlp,  BPF_MOV_REG(BPF_REG_3, dnp->dn_reg));
> > +	if (isreg == DT_ISREG)
> > +		emit(dlp, BPF_MOV_REG(BPF_REG_4, val));
> > +	else if (isreg == DT_ISIMM)
> > +		emit(dlp, BPF_MOV_IMM(BPF_REG_4, val));
> > +
> >   	idp = dt_dlib_get_func(yypcb->pcb_hdl, fname);
> >   	assert(idp != NULL);
> >   	dt_regset_xalloc(drp, BPF_REG_0);
> > @@ -4632,13 +4640,13 @@ dt_cg_subr_arg_to_tstring(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
> >   static void
> >   dt_cg_subr_basename(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   {
> > -	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_basename");
> > +	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_basename", DT_ISIGN, 0);
> >   }
> >   static void
> >   dt_cg_subr_dirname(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   {
> > -	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_dirname");
> > +	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_dirname", DT_ISIGN, 0);
> >   }
> >   static void
> > @@ -4703,7 +4711,7 @@ dt_cg_subr_index(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   static void
> >   dt_cg_subr_lltostr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   {
> > -	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_lltostr");
> > +	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_lltostr", DT_ISIGN, 0);
> >   }
> >   static void
> > @@ -5867,7 +5875,7 @@ dt_cg_subr_htonll(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   static void
> >   dt_cg_subr_inet_ntoa(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> >   {
> > -	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_inet_ntoa");
> > +	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_inet_ntoa", DT_ISIGN, 0);
> >   }
> >   typedef void dt_cg_subr_f(dt_node_t *, dt_irlist_t *, dt_regset_t *);
> 
> _______________________________________________
> DTrace-devel mailing list
> DTrace-devel at oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/dtrace-devel