Re: [PATCH 06/22] plugins: Create TCGHelperInfo for all out-of-line callbacks

[Pierrick Bouvier]

On 3/19/24 23:51, Richard Henderson wrote:
> On 3/19/24 03:12, Pierrick Bouvier wrote:
> > On 3/16/24 05:57, Richard Henderson wrote:
> > > TCGHelperInfo includes the ABI for every function call.
> > >
> > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > > ---
> > >    include/qemu/plugin.h |  1 +
> > >    plugins/core.c        | 51 ++++++++++++++++++++++++++++++++++++++-----
> > >    2 files changed, 46 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
> > > index 143262dca8..793c44f1f2 100644
> > > --- a/include/qemu/plugin.h
> > > +++ b/include/qemu/plugin.h
> > > @@ -92,6 +92,7 @@ struct qemu_plugin_dyn_cb {
> > >        union {
> > >            struct {
> > >                union qemu_plugin_cb_sig f;
> > > +            TCGHelperInfo *info;
> > >            } regular;
> > >            struct {
> > >                qemu_plugin_u64 entry;
> > > diff --git a/plugins/core.c b/plugins/core.c
> > > index 837c373690..b0a2e80874 100644
> > > --- a/plugins/core.c
> > > +++ b/plugins/core.c
> > > @@ -338,12 +338,26 @@ void plugin_register_dyn_cb__udata(GArray **arr,
> > >                                       enum qemu_plugin_cb_flags flags,
> > >                                       void *udata)
> > >    {
> > > -    struct qemu_plugin_dyn_cb *dyn_cb = plugin_get_dyn_cb(arr);
> > > +    static TCGHelperInfo info[3] = {
> > > +        [QEMU_PLUGIN_CB_NO_REGS].flags = TCG_CALL_NO_RWG | TCG_CALL_PLUGIN,
> > > +        [QEMU_PLUGIN_CB_R_REGS].flags = TCG_CALL_NO_WG | TCG_CALL_PLUGIN,
> > > +        [QEMU_PLUGIN_CB_RW_REGS].flags = TCG_CALL_PLUGIN,
> > > +        /*
> > > +         * Match qemu_plugin_vcpu_udata_cb_t:
> > > +         *   void (*)(uint32_t, void *)
> > > +
> >
> > Any chance we could have a static assert ensuring this?
> > I know it's possible in C11, but I don't know if glib offers something for this.
>
> I don't see how.  While you could ask questions about the pointer type
> qemu_plugin_vcpu_udata_cb_t, you can't ask questions about the function 
> arguments.

I was thinking about something similar to:
static_assert(typeof(qemu_plugin_vcpu_udata_cb_t) == void (*)(uint32_t, 
void *));

But I don't think it's possible to express this in C standard before 11.

> r~