[DTrace-devel] [PATCH 04/12] options: report EDT_NOREG for iregs < DIF_DIR_NREGS

[Eugene Loh]

See my comments to the 03/12 patch.

On 1/5/24 00:26, Kris Van Hees via DTrace-devel wrote:
> The trampoline generation code hardcodes the use of %r7 and %r8, which
> means that iregs cannot be less than 8 (DIF_DIR_NREGS).
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
>   libdtrace/dt_options.c            |  4 +++-
>   test/unittest/options/tst.iregs.r | 26 +++++++-------------------
>   2 files changed, 10 insertions(+), 20 deletions(-)
>
> diff --git a/libdtrace/dt_options.c b/libdtrace/dt_options.c
> index 6f7cf9e2..18b8f43a 100644
> --- a/libdtrace/dt_options.c
> +++ b/libdtrace/dt_options.c
> @@ -1,6 +1,6 @@
>   /*
>    * Oracle Linux DTrace.
> - * Copyright (c) 2007, 2023, Oracle and/or its affiliates. All rights reserved.
> + * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
>    * Licensed under the Universal Permissive License v 1.0 as shown at
>    * http://oss.oracle.com/licenses/upl.
>    */
> @@ -266,6 +266,8 @@ dt_opt_iregs(dtrace_hdl_t *dtp, const char *arg, uintptr_t option)
>   
>   	if (arg == NULL || (n = atoi(arg)) <= 0 || n > DIF_DIR_NREGS)
>   		return dt_set_errno(dtp, EDT_BADOPTVAL);
> +	if (n < DIF_DIR_NREGS)
> +		return dt_set_errno(dtp, EDT_NOREG);
>   
>   	dtp->dt_conf.dtc_difintregs = n;
>   	return 0;
> diff --git a/test/unittest/options/tst.iregs.r b/test/unittest/options/tst.iregs.r
> index 4926b28d..f67e7b07 100644
> --- a/test/unittest/options/tst.iregs.r
> +++ b/test/unittest/options/tst.iregs.r
> @@ -1,25 +1,13 @@
>   7
>   iregs 8 gives 0
> -7
> -iregs 7 gives 0
> -7
> -iregs 6 gives 0
> +iregs 7 gives 1
> +iregs 6 gives 1
>   iregs 5 gives 1
>   iregs 4 gives 1
>   iregs 3 gives 1
>   -- @@stderr --
> -dtrace: invalid probe specifier BEGIN {
> -        a = b = c = d = e = f = g = h = i = j = k = l = 1;
> -        trace(a + b * (c + d * (e + f * (g + h * (i + j * (k + l))))));
> -        exit(0);
> -    }: Insufficient registers to generate code
> -dtrace: invalid probe specifier BEGIN {
> -        a = b = c = d = e = f = g = h = i = j = k = l = 1;
> -        trace(a + b * (c + d * (e + f * (g + h * (i + j * (k + l))))));
> -        exit(0);
> -    }: Insufficient registers to generate code
> -dtrace: invalid probe specifier BEGIN {
> -        a = b = c = d = e = f = g = h = i = j = k = l = 1;
> -        trace(a + b * (c + d * (e + f * (g + h * (i + j * (k + l))))));
> -        exit(0);
> -    }: Insufficient registers to generate code
> +dtrace: failed to set -x iregs: Insufficient registers to generate code
> +dtrace: failed to set -x iregs: Insufficient registers to generate code
> +dtrace: failed to set -x iregs: Insufficient registers to generate code
> +dtrace: failed to set -x iregs: Insufficient registers to generate code
> +dtrace: failed to set -x iregs: Insufficient registers to generate code