Re: [Qemu-devel] [PATCH 4/6] tcg-i386: Implement small forward branches.

[Aurelien Jarno]

On Thu, Jan 07, 2010 at 10:46:59AM -0800, Richard Henderson wrote:
> There are places, like brcond2, where we know that the destination
> of a forward branch will be within 127 bytes.
> 
> Add the R_386_PC8 relocation type to support this.  Add a flag to
> tcg_out_jxx and tcg_out_brcond* to enable it.  Set the flag in the
> brcond2 label_next branches; pass along the input flag otherwise.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  elf.h                 |    2 +
>  tcg/i386/tcg-target.c |  116 
> +++++++++++++++++++++++++++++++++----------------
>  2 files changed, 80 insertions(+), 38 deletions(-)
> 
> diff --git a/elf.h b/elf.h
> index 11674d7..c84c8ab 100644
> --- a/elf.h
> +++ b/elf.h
> @@ -243,6 +243,8 @@ typedef struct {
>  #define R_386_GOTOFF 9
>  #define R_386_GOTPC  10
>  #define R_386_NUM    11
> +/* Not a dynamic reloc, so not included in R_386_NUM.  Used in TCG.  */
> +#define R_386_PC8    23
>  
>  #define R_MIPS_NONE          0
>  #define R_MIPS_16            1
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index 972b102..e1691b3 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -61,6 +61,12 @@ static void patch_reloc(uint8_t *code_ptr, int type,
>      case R_386_PC32:
>          *(uint32_t *)code_ptr = value - (long)code_ptr;
>          break;
> +    case R_386_PC8:
> +        value -= (long)code_ptr;
> +        if (value != (int8_t)value)
> +            tcg_abort();

This does not conforms to CODING_STYLE, curly brackets are missing.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net