[PATCH v2] LoongArch: gas: Adjust DWARF CIE alignment factors

[Jinyang He]

On 2024-05-06 17:23, mengqinggang wrote:

> Set DWARF2_CIE_DATA_ALIGNMENT (data alignment factors) to -8.
> It helps to save space.
>
> Data Alignment Factor
> A signed LEB128 encoded value that is factored out of all offset
> instructions that are associated with this CIE or its FDEs. This value
> shall be multiplied by the register offset argument of an offset
> instruction to obtain the new offset value.
> ---
>   gas/config/tc-loongarch.h | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/gas/config/tc-loongarch.h b/gas/config/tc-loongarch.h
> index e0d0962e5f0..8b6fee0ac23 100644
> --- a/gas/config/tc-loongarch.h
> +++ b/gas/config/tc-loongarch.h
> @@ -101,15 +101,19 @@ extern bool loongarch_frag_align_code (int, int);
>   
>   #define TC_FORCE_RELOCATION_LOCAL(FIX) 1
>   
> -/* Adjust debug_line after relaxation.  */
> -#define DWARF2_USE_FIXED_ADVANCE_PC 1
> -
>   /* Values passed to md_apply_fix don't include symbol values.  */
>   #define MD_APPLY_SYM_VALUE(FIX) 0
>   
>   #define TARGET_USE_CFIPOP 1
> -#define DWARF2_DEFAULT_RETURN_COLUMN 1 /* $ra.  */
> -#define DWARF2_CIE_DATA_ALIGNMENT -4
> +/* Adjust debug_line after relaxation.  */
> +#define DWARF2_USE_FIXED_ADVANCE_PC   1
> +
> +/* FDE Data Alignment Factor.
> +   FDE Code Alignment Factor (DWARF2_LINE_MIN_INSN_LENGTH) should be 1
> +   because DW_CFA_advance_loc need to be relocated in bytes
> +   when linker relaxation.  */
> +#define DWARF2_CIE_DATA_ALIGNMENT     (-8)

Should be (-4) for loongarch32?


> +#define DWARF2_DEFAULT_RETURN_COLUMN  1	    /* FDE Return Address Register.  */
>   
>   #define tc_cfi_frame_initial_instructions	\
>     loongarch_cfi_frame_initial_instructions