[Patch] Gas support for MIPS Compact EH

[Maciej W. Rozycki]

On Tue, 4 Feb 2014, Moore, Catherine wrote:

> I finally got some time to work on fixing up (with some help from Bernd) 
> the binutils submission for compact EH.  Hopefully, the review comments 
> have been addressed.
> 
> The current patch has been expanded to include all of binutils. 
> 
> As a reminder, the spec is available here:
> https://github.com/MentorEmbedded/cxx-abi/blob/master/MIPSCompactEH.pdf

 Just a couple of minor nits I found skimming over the change.  These of 
course by no means invalidate your excellent work!

> diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
> index 34f1bf0..90688f1 100644
> --- a/gas/config/tc-mips.c
> +++ b/gas/config/tc-mips.c
> @@ -18249,3 +18256,13 @@ tc_mips_regname_to_dw2regnum (char *regname)
>  
>    return regnum;
>  }
> +
> +#if defined (OBJ_ELF)
> +bfd_reloc_code_real_type
> +mips_cfi_reloc_for_encoding (int encoding)
> +{
> +  if ((encoding & 0x70) == DW_EH_PE_datarel)
> +    return BFD_RELOC_GPREL32;
> +  return BFD_RELOC_32_PCREL;
> +}
> +#endif

 No need to check for OBJ_ELF anymore, we don't support non-ELF targets 
these days (cf. commit f3ded42a5d397a8dd1548e68a647c690088d3fbd).

> diff --git a/gas/config/tc-mips.h b/gas/config/tc-mips.h
> index c7eaa04..a300062 100644
> --- a/gas/config/tc-mips.h
> +++ b/gas/config/tc-mips.h
> @@ -190,4 +192,18 @@ extern int tc_mips_regname_to_dw2regnum (char *regname);
>  #define DWARF2_DEFAULT_RETURN_COLUMN 31
>  #define DWARF2_CIE_DATA_ALIGNMENT (-4)
>  
> +#if defined (OBJ_ELF)
> +
> +#define tc_cfi_reloc_for_encoding mips_cfi_reloc_for_encoding
> +extern bfd_reloc_code_real_type mips_cfi_reloc_for_encoding (int encoding);
> +
> +#define tc_cfi_special_encoding(e)				   \
> +  ((e) == (DW_EH_PE_sdata4 | DW_EH_PE_datarel | DW_EH_PE_indirect) \
> +   || (e) == (DW_EH_PE_sdata4 | DW_EH_PE_pcrel))
> +
> +#define tc_compact_eh_opcode_stop 0x5c
> +#define tc_compact_eh_opcode_pad 0x5f
> +
> +#endif /* OBJ_ELF */
> +
>  #endif /* TC_MIPS */

 Likewise.

> diff --git a/ld/emultempl/mipself.em b/ld/emultempl/mipself.em
> index 02043b7..252af0f 100644
> --- a/ld/emultempl/mipself.em
> +++ b/ld/emultempl/mipself.em
> @@ -252,11 +253,13 @@ EOF
>  PARSE_AND_LIST_PROLOGUE='
>  #define OPTION_INSN32			301
>  #define OPTION_NO_INSN32		(OPTION_INSN32 + 1)
> +#define OPTION_PCREL_EH_RELOC		303
>  '

 (OPTION_NO_INSN32 + 1) please instead -- this allows easy option 
insertion and removal without the need to renumber options or leaving 
holes behind.

  Maciej