Re: [PATCH v6 4/6] target/riscv: Add support for PC-relative translation

[liweiwei]

On 2023/4/4 23:27, Richard Henderson wrote:
> On 4/4/23 08:14, liweiwei wrote:
> > On 2023/4/4 22:57, Richard Henderson wrote:
> > > On 4/4/23 07:33, liweiwei wrote:
> > > > If we want to hide all of them in gen_pc_plus_diff,  then we need 
> > > > calculate the diff for pc_succ_insn or introduce a new API for it, 
> > > > since we need get the successor pc in many instructions.
> > > >
> > > > And the logic for gen_goto_tb or gen_set_pc_imm also need update.
> > >
> > > Yes, exactly.
> > Sorry, I didn't find benefits from this. If we do this, we'll firstly 
> > calculate the diff = pc_succ_insn - pc_next, then we add it with 
> > pc_next - pc_save to get the relative address to env->pc.
>
> It will me simpler because you'll move all of the calculations into a 
> helper function.
helper? Do you mean gen_pc_plus_diff?
> The trans_* functions will be supplying a immediate directly:
>
>   * for auipc, this is a->imm,
Yeah. this will be simpler in trans_, however the total calculation is 
the same. we just move a->imm + pc_next to gen_pc_plus_diff.
>   * for jalr, this is 0.

Not 0, but pc_succ_insn - pc_next. This may be the case in many place.

Regards,

Weiwei Li

> r~