Re: [ARM/FDPIC v5 07/21] [ARM] FDPIC: Avoid saving/restoring r9 on stack since it is read-only

[Kyrill Tkachov <kyrylo dot tkachov at foss dot arm dot com>]

On 5/15/19 1:39 PM, Christophe Lyon wrote:
> 2019-XX-XX  Christophe Lyon <christophe.lyon@st.com>
>         Mickaël Guêné <mickael.guene@st.com>
>
>         gcc/
>         * config/arm/arm.h (PIC_REGISTER_MAY_NEED_SAVING): New helper.
>         * config/arm/arm.c (arm_compute_save_reg0_reg12_mask): Handle
>         FDPIC.
Ok once the rest of the series is approved.

Thanks,

Kyrill


> Change-Id: I0f3b2023ab2a2a0433dfe081dac6bbb194b7a76c
>
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index d9397b5..dbd1671 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -19651,9 +19651,7 @@ arm_compute_save_reg0_reg12_mask (void)
>            save_reg_mask |= (1 << reg);
>
>        /* Also save the pic base register if necessary.  */
> -      if (flag_pic
> -         && !TARGET_SINGLE_PIC_BASE
> -         && arm_pic_register != INVALID_REGNUM
> +      if (PIC_REGISTER_MAY_NEED_SAVING
>            && crtl->uses_pic_offset_table)
>          save_reg_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;
>      }
> @@ -19685,9 +19683,7 @@ arm_compute_save_reg0_reg12_mask (void)
>
>        /* If we aren't loading the PIC register,
>           don't stack it even though it may be live.  */
> -      if (flag_pic
> -         && !TARGET_SINGLE_PIC_BASE
> -         && arm_pic_register != INVALID_REGNUM
> +      if (PIC_REGISTER_MAY_NEED_SAVING
>            && (df_regs_ever_live_p (PIC_OFFSET_TABLE_REGNUM)
>                || crtl->uses_pic_offset_table))
>          save_reg_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;
> diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
> index 7b50ef5..45c0e2b 100644
> --- a/gcc/config/arm/arm.h
> +++ b/gcc/config/arm/arm.h
> @@ -1967,6 +1967,13 @@ extern unsigned arm_pic_register;
>                     || label_mentioned_p (get_pool_constant 
> (X)))))       \
>           || tls_mentioned_p (X))
>
> +/* We may want to save the PIC register if it is a dedicated one.  */
> +#define PIC_REGISTER_MAY_NEED_SAVING                   \
> +  (flag_pic                                            \
> +   && !TARGET_SINGLE_PIC_BASE                          \
> +   && !TARGET_FDPIC                                    \
> +   && arm_pic_register != INVALID_REGNUM)
> +
>  /* We need to know when we are making a constant pool; this determines
>     whether data needs to be in the GOT or can be referenced via a GOT
>     offset.  */
> --
> 2.6.3