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Re: [PATCH] tcg: Introduce tcg_remove_ops_after
From: |
Peter Maydell |
Subject: |
Re: [PATCH] tcg: Introduce tcg_remove_ops_after |
Date: |
Mon, 7 Jun 2021 14:51:33 +0100 |
On Fri, 4 Jun 2021 at 22:27, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Introduce a function to remove everything emitted
> since a given point.
>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> include/tcg/tcg.h | 1 +
> tcg/tcg.c | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/include/tcg/tcg.h b/include/tcg/tcg.h
> index 74cb345308..6895246fab 100644
> --- a/include/tcg/tcg.h
> +++ b/include/tcg/tcg.h
> @@ -1081,6 +1081,7 @@ TCGOp *tcg_emit_op(TCGOpcode opc);
> void tcg_op_remove(TCGContext *s, TCGOp *op);
> TCGOp *tcg_op_insert_before(TCGContext *s, TCGOp *op, TCGOpcode opc);
> TCGOp *tcg_op_insert_after(TCGContext *s, TCGOp *op, TCGOpcode opc);
> +void tcg_remove_ops_after(TCGOp *op);
A doc comment would be nice.
> void tcg_optimize(TCGContext *s);
>
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index 0dc271aac9..262dbba1fd 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -2649,6 +2649,19 @@ void tcg_op_remove(TCGContext *s, TCGOp *op)
> #endif
> }
>
> +void tcg_remove_ops_after(TCGOp *op)
> +{
> + TCGContext *s = tcg_ctx;
> +
> + while (true) {
> + TCGOp *last = tcg_last_op();
> + if (last == op) {
> + return;
> + }
> + tcg_op_remove(s, last);
> + }
> +}
This looks OK as far as TCG proper goes, but is it going to confuse
the TCG plugin infrastructure if a frontend generates a bunch of
TCG IR and then winds back the insn stream and generates something
else instead ? I see some calls from tcg/ into plugin related
functions, so I'm not sure...
thanks
-- PMM