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

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

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~