Re: [Qemu-devel] [PATCH v6 15/25] tcg/s390: Implement goto_ptr

[Aurelien Jarno]

On 2017-05-02 12:22, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  tcg/s390/tcg-target.h     |  2 +-
>  tcg/s390/tcg-target.inc.c | 24 +++++++++++++++++++++---
>  2 files changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/tcg/s390/tcg-target.h b/tcg/s390/tcg-target.h
> index 6b7bcfb..957f0c0 100644
> --- a/tcg/s390/tcg-target.h
> +++ b/tcg/s390/tcg-target.h
> @@ -92,7 +92,7 @@ extern uint64_t s390_facilities;
>  #define TCG_TARGET_HAS_mulsh_i32      0
>  #define TCG_TARGET_HAS_extrl_i64_i32  0
>  #define TCG_TARGET_HAS_extrh_i64_i32  0
> -#define TCG_TARGET_HAS_goto_ptr       0
> +#define TCG_TARGET_HAS_goto_ptr       1
>  
>  #define TCG_TARGET_HAS_div2_i64       1
>  #define TCG_TARGET_HAS_rot_i64        1
> diff --git a/tcg/s390/tcg-target.inc.c b/tcg/s390/tcg-target.inc.c
> index a679280..5d7083e 100644
> --- a/tcg/s390/tcg-target.inc.c
> +++ b/tcg/s390/tcg-target.inc.c
> @@ -1741,9 +1741,14 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode 
> opc,
>  
>      switch (opc) {
>      case INDEX_op_exit_tb:
> -        /* return value */
> -        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_R2, args[0]);
> -        tgen_gotoi(s, S390_CC_ALWAYS, tb_ret_addr);
> +        /* Reuse the zeroing that exists for goto_ptr.  */
> +        a0 = args[0];
> +        if (a0 == 0) {
> +            tgen_gotoi(s, S390_CC_ALWAYS, s->code_gen_epilogue);
> +        } else {
> +            tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_R2, a0);
> +            tgen_gotoi(s, S390_CC_ALWAYS, tb_ret_addr);
> +        }
>          break;
>  
>      case INDEX_op_goto_tb:
> @@ -1767,6 +1772,10 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode 
> opc,
>          s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s);
>          break;
>  
> +    case INDEX_op_goto_ptr:
> +        tcg_out_insn(s, RR, BCR, S390_CC_ALWAYS, args[0]);
> +        break;
> +
>      OP_32_64(ld8u):
>          /* ??? LLC (RXY format) is only present with the extended-immediate
>             facility, whereas LLGC is always present.  */
> @@ -2241,6 +2250,7 @@ static const TCGTargetOpDef s390_op_defs[] = {
>      { INDEX_op_exit_tb, { } },
>      { INDEX_op_goto_tb, { } },
>      { INDEX_op_br, { } },
> +    { INDEX_op_goto_ptr, { "r" } },
>  
>      { INDEX_op_ld8u_i32, { "r", "r" } },
>      { INDEX_op_ld8s_i32, { "r", "r" } },
> @@ -2439,6 +2449,14 @@ static void tcg_target_qemu_prologue(TCGContext *s)
>      /* br %r3 (go to TB) */
>      tcg_out_insn(s, RR, BCR, S390_CC_ALWAYS, tcg_target_call_iarg_regs[1]);
>  
> +    /*
> +     * Return path for goto_ptr. Set return value to 0, a-la exit_tb,
> +     * and fall through to the rest of the epilogue.
> +     */
> +    s->code_gen_epilogue = s->code_ptr;
> +    tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_R2, 0);
> +
> +    /* TB epilogue */
>      tb_ret_addr = s->code_ptr;
>  
>      /* lmg %r6,%r15,fs+48(%r15) (restore registers) */

Reviewed-by: Aurelien Jarno <address@hidden>
Tested-by: Aurelien Jarno <address@hidden>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
address@hidden                 http://www.aurel32.net