Re: [PATCH 1/7] tcg: Introduce INDEX_op_plugin_pc

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

On 4/15/24 21:06, Richard Henderson wrote:
> Add an opcode to find a code address within the current insn,
> for later use with unwinding.  Generate the code generically
> using tcg_reg_alloc_do_movi.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   include/tcg/tcg-op-common.h |  1 +
>   include/tcg/tcg-opc.h       |  1 +
>   tcg/tcg-op.c                |  5 +++++
>   tcg/tcg.c                   | 10 ++++++++++
>   4 files changed, 17 insertions(+)
> 
> diff --git a/include/tcg/tcg-op-common.h b/include/tcg/tcg-op-common.h
> index 009e2778c5..a32c88a182 100644
> --- a/include/tcg/tcg-op-common.h
> +++ b/include/tcg/tcg-op-common.h
> @@ -76,6 +76,7 @@ void tcg_gen_lookup_and_goto_ptr(void);
>   
>   void tcg_gen_plugin_cb(unsigned from);
>   void tcg_gen_plugin_mem_cb(TCGv_i64 addr, unsigned meminfo);
> +void tcg_gen_plugin_pc(TCGv_ptr);
>   
>   /* 32 bit ops */
>   
> diff --git a/include/tcg/tcg-opc.h b/include/tcg/tcg-opc.h
> index 546eb49c11..087d1b82da 100644
> --- a/include/tcg/tcg-opc.h
> +++ b/include/tcg/tcg-opc.h
> @@ -199,6 +199,7 @@ DEF(goto_ptr, 0, 1, 0, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
>   
>   DEF(plugin_cb, 0, 0, 1, TCG_OPF_NOT_PRESENT)
>   DEF(plugin_mem_cb, 0, 1, 1, TCG_OPF_NOT_PRESENT)
> +DEF(plugin_pc, 1, 0, 0, TCG_OPF_NOT_PRESENT)
>   
>   /* Replicate ld/st ops for 32 and 64-bit guest addresses. */
>   DEF(qemu_ld_a32_i32, 1, 1, 1,
> diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
> index eff3728622..b8ca78cbe4 100644
> --- a/tcg/tcg-op.c
> +++ b/tcg/tcg-op.c
> @@ -322,6 +322,11 @@ void tcg_gen_plugin_mem_cb(TCGv_i64 addr, unsigned meminfo)
>       tcg_gen_op2(INDEX_op_plugin_mem_cb, tcgv_i64_arg(addr), meminfo);
>   }
>   
> +void tcg_gen_plugin_pc(TCGv_ptr arg)
> +{
> +    tcg_gen_op1(INDEX_op_plugin_pc, tcgv_ptr_arg(arg));
> +}
> +
>   /* 32 bit ops */
>   
>   void tcg_gen_discard_i32(TCGv_i32 arg)
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index d248c52e96..42e2b53729 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -4701,6 +4701,13 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOp *op)
>       }
>   }
>   
> +static void tcg_reg_alloc_plugin_pc(TCGContext *s, const TCGOp *op)
> +{
> +    tcg_reg_alloc_do_movi(s, arg_temp(op->args[0]),
> +                          (uintptr_t)tcg_splitwx_to_rx(s->code_ptr),
> +                          op->life, output_pref(op, 0));
> +}
> +
>   /*
>    * Specialized code generation for INDEX_op_dup_vec.
>    */
> @@ -6208,6 +6215,9 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb, uint64_t pc_start)
>           case INDEX_op_mov_vec:
>               tcg_reg_alloc_mov(s, op);
>               break;
> +        case INDEX_op_plugin_pc:
> +            tcg_reg_alloc_plugin_pc(s, op);
> +            break;
>           case INDEX_op_dup_vec:
>               tcg_reg_alloc_dup(s, op);
>               break;

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>