[DTrace-devel] [PATCH 3/7] Add disassembler support for dynamic type vars

[Kris Van Hees]

On Thu, May 26, 2022 at 07:24:50PM -0700, Eugene Loh via DTrace-devel wrote:
> I do not really understand this code but what the heck:
> Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
> 
> I assume this had no counterpart in DTv1?

Correct.  There was no annotation for this in the legacy version.

> Also, a test would be good.  Presumably a test would not yet work in this
> patch, but it could be added to patch 5.

I will have a look at this.  I do agree a test should be added, but #5/7 does
not seem to be the right place.  Maybe I can put this patch *after* #5/7 and
then add a test to this one (and also update the overall annotation one to
include the args variable).  That would probably work better overall.

> Also, never mind my own preferences on this subject, but the indentation for
> the continuation line in dt_parser.c looks different from what I think you
> normally try to do.  Maybe it's a copy-and-paste from above, but you
> intended to indent more due to the "else"?  (Or possibly I'm totally
> misreading the indentation due to mailer whackiness.)

Ah yes, that was a copy/paste that didn't get cleaned up.  Fixing.  Thanks
for pointing it out.

> On 5/26/22 11:24, Kris Van Hees via DTrace-devel wrote:
> > The args[] built-in variable is a special array where each element has
> > its own datatype.  The overall datatype is considered the 'dynamic type'
> > which is expressed as 'any'.
> > 
> > Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> > ---
> >   include/dtrace/dif_defines.h | 3 ++-
> >   libdtrace/dt_dis.c           | 3 +++
> >   libdtrace/dt_parser.c        | 4 ++++
> >   3 files changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/dtrace/dif_defines.h b/include/dtrace/dif_defines.h
> > index 9f30e649..43824646 100644
> > --- a/include/dtrace/dif_defines.h
> > +++ b/include/dtrace/dif_defines.h
> > @@ -2,7 +2,7 @@
> >    * Licensed under the Universal Permissive License v 1.0 as shown at
> >    * http://oss.oracle.com/licenses/upl.
> >    *
> > - * Copyright (c) 2009, 2021, Oracle and/or its affiliates. All rights reserved.
> > + * Copyright (c) 2009, 2022, Oracle and/or its affiliates. All rights reserved.
> >    */
> >   /*
> > @@ -263,6 +263,7 @@ typedef uint32_t	dif_instr_t;
> >   #define DIF_TYPE_CTF		0
> >   #define DIF_TYPE_STRING		1
> > +#define DIF_TYPE_ANY		2
> >   #define DIF_TF_BYREF		0x1
> > diff --git a/libdtrace/dt_dis.c b/libdtrace/dt_dis.c
> > index 58c02fd5..9a365a6b 100644
> > --- a/libdtrace/dt_dis.c
> > +++ b/libdtrace/dt_dis.c
> > @@ -471,6 +471,9 @@ dt_dis_typestr(const dtrace_diftype_t *t, char *buf, size_t len)
> >   	case DIF_TYPE_STRING:
> >   		strcpy(kind, "string");
> >   		break;
> > +	case DIF_TYPE_ANY:
> > +		strcpy(kind, "any");
> > +		break;
> >   	default:
> >   		snprintf(kind, sizeof(kind), "0x%x", t->dtdt_kind);
> >   	}
> > diff --git a/libdtrace/dt_parser.c b/libdtrace/dt_parser.c
> > index 7c5c30c9..e410f993 100644
> > --- a/libdtrace/dt_parser.c
> > +++ b/libdtrace/dt_parser.c
> > @@ -4810,6 +4810,10 @@ dt_node_diftype(dtrace_hdl_t *dtp, const dt_node_t *dnp, dtrace_diftype_t *tp)
> >   	    dnp->dn_type == DT_STR_TYPE(dtp)) {
> >   		tp->dtdt_kind = DIF_TYPE_STRING;
> >   		tp->dtdt_ckind = CTF_K_UNKNOWN;
> > +	} else if (dnp->dn_ctfp == DT_DYN_CTFP(dtp) &&
> > +	    dnp->dn_type == DT_DYN_TYPE(dtp)) {
> > +		tp->dtdt_kind = DIF_TYPE_ANY;
> > +		tp->dtdt_ckind = CTF_K_UNKNOWN;
> >   	} else {
> >   		tp->dtdt_kind = DIF_TYPE_CTF;
> >   		tp->dtdt_ckind = ctf_type_kind(dnp->dn_ctfp,
> 
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