Re: [Qemu-devel] [PATCH v3 07/10] target/i386: introduce gen_jr helper to generate lookup_and_goto_ptr

[Richard Henderson]

On 04/26/2017 08:23 AM, Emilio G. Cota wrote:
> +gen_eob_worker(DisasContext *s, bool inhibit, bool recheck_tf, TCGv jr)
>   {
>       gen_update_cc_op(s);
>   
> @@ -2530,6 +2532,13 @@ static void gen_eob_worker(DisasContext *s, bool inhibit, bool recheck_tf)
>           tcg_gen_exit_tb(0);
>       } else if (s->tf) {
>           gen_helper_single_step(cpu_env);
> +    } else if (jr) {
...
> -        gen_eob_worker(s, false, true);
> +        gen_eob_worker(s, false, true, NULL);

You cannot use NULL.  While we abuse a pointer type for TCGv, that's because C 
doesn't have type verification for different integral types.

You need to use

    TCGv unused;
    TCGV_UNUSED(unused);

and

    if (TCGV_IS_UNUSED(foo))

(As it happens, I do have a branch that tries to clean this up, so that this 
kind of thing is less unwieldy.  Perhaps I'll get to it this cycle...)

> +        tcg_gen_ld_tl(vaddr, cpu_env, offsetof(CPUX86State, segs[R_CS].base));
> +        tcg_gen_add_tl(vaddr, vaddr, jr);

tcg_gen_add_tl(vaddr, jr, cpu_seg_base[R_CS]);


r~