linux-kernel - Re: [PATCH 2/2] verification/rvgen: Do not generate unused variables

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Message-ID: <87c5e103780e8d8d0cef27cb3cba69ab0bcb9b1f.camel@redhat.com>
Date: Mon, 21 Jul 2025 14:07:15 +0200
From: Gabriele Monaco <gmonaco@...hat.com>
To: Nam Cao <namcao@...utronix.de>, Steven Rostedt <rostedt@...dmis.org>, 
 Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
 <mathieu.desnoyers@...icios.com>, 	linux-trace-kernel@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] verification/rvgen: Do not generate unused variables

On Fri, 2025-07-18 at 16:58 +0200, Nam Cao wrote:
> ltl2k generates all variable definition in both ltl_start() and
> ltl_possible_next_states(). However, these two functions may not use
> all
> the variables, causing "unused variable" compiler warning.
> 
> Change the script to only generate used variables.
> 
> Signed-off-by: Nam Cao <namcao@...utronix.de>

Tried both patches and they seem to work as intended.

Reviewed-by: Gabriele Monaco <gmonaco@...hat.com>

Thanks,
Gabriele

> ---
>  tools/verification/rvgen/rvgen/ltl2k.py | 25 +++++++++++++++++++++--
> --
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/verification/rvgen/rvgen/ltl2k.py
> b/tools/verification/rvgen/rvgen/ltl2k.py
> index 59da351792ec..b075f98d50c4 100644
> --- a/tools/verification/rvgen/rvgen/ltl2k.py
> +++ b/tools/verification/rvgen/rvgen/ltl2k.py
> @@ -106,20 +106,25 @@ class ltl2k(generator.Monitor):
>          ])
>          return buf
>  
> -    def _fill_atom_values(self):
> +    def _fill_atom_values(self, required_values):
>          buf = []
>          for node in self.ltl:
> -            if node.op.is_temporal():
> +            if str(node) not in required_values:
>                  continue
>  
>              if isinstance(node.op, ltl2ba.AndOp):
>                  buf.append("\tbool %s = %s && %s;" % (node,
> node.op.left, node.op.right))
> +                required_values |= {str(node.op.left),
> str(node.op.right)}
>              elif isinstance(node.op, ltl2ba.OrOp):
>                  buf.append("\tbool %s = %s || %s;" % (node,
> node.op.left, node.op.right))
> +                required_values |= {str(node.op.left),
> str(node.op.right)}
>              elif isinstance(node.op, ltl2ba.NotOp):
>                  buf.append("\tbool %s = !%s;" % (node,
> node.op.child))
> +                required_values.add(str(node.op.child))
>  
>          for atom in self.atoms:
> +            if atom.lower() not in required_values:
> +                continue
>              buf.append("\tbool %s = test_bit(LTL_%s, mon->atoms);" %
> (atom.lower(), atom))
>  
>          buf.reverse()
> @@ -135,7 +140,13 @@ class ltl2k(generator.Monitor):
>              "ltl_possible_next_states(struct ltl_monitor *mon,
> unsigned int state, unsigned long *next)",
>              "{"
>          ]
> -        buf.extend(self._fill_atom_values())
> +
> +        required_values = set()
> +        for node in self.ba:
> +            for o in sorted(node.outgoing):
> +                required_values |= o.labels
> +
> +        buf.extend(self._fill_atom_values(required_values))
>          buf.extend([
>              "",
>              "\tswitch (state) {"
> @@ -166,7 +177,13 @@ class ltl2k(generator.Monitor):
>              "static void ltl_start(struct task_struct *task, struct
> ltl_monitor *mon)",
>              "{"
>          ]
> -        buf.extend(self._fill_atom_values())
> +
> +        required_values = set()
> +        for node in self.ba:
> +            if node.init:
> +                required_values |= node.labels
> +
> +        buf.extend(self._fill_atom_values(required_values))
>          buf.append("")
>  
>          for node in self.ba: