Re: [PATCH v2] MIPS: the default output fellows triple and with-arch

[Richard Sandiford <richard.sandiford@arm.com>]

YunQiang Su <yunqiang.su@cipunited.com> writes:
> PR 25494.
>
> 1. as fellows the isa level in triple of target
>    and the --with-arch buildtime option:
>    > as -march=from-abi xx.s
>    > as xx.s
> 2. ld fellows the isa level in triple of target
>    > ld -r -b binary xx.dat -o xx.o
> ---
>  bfd/Makefile.in                               |  1 +
>  bfd/config.bfd                                | 48 ++++++++++++-
>  bfd/configure                                 |  5 ++
>  bfd/configure.ac                              |  4 ++
>  bfd/elfxx-mips.c                              | 61 +++++++++++++++-
>  .../binutils-all/mips/mips-note-2-n32.d       |  1 +
>  gas/config/tc-mips.c                          | 70 +++++++++++++++++--
>  gas/configure                                 | 20 +++++-
>  gas/configure.ac                              | 18 ++++-
>  gold/configure.tgt                            | 14 ++++
>  ld/configure.tgt                              | 12 +++-
>  11 files changed, 241 insertions(+), 13 deletions(-)
>
> diff --git a/bfd/Makefile.in b/bfd/Makefile.in
> index 82aa96f30e5..7b7b262d64e 100644
> --- a/bfd/Makefile.in
> +++ b/bfd/Makefile.in
> @@ -332,6 +332,7 @@ CPPFLAGS = @CPPFLAGS@
>  CYGPATH_W = @CYGPATH_W@
>  DATADIRNAME = @DATADIRNAME@
>  DEBUGDIR = @DEBUGDIR@
> +DEFAULT_ARCH = @DEFAULT_ARCH@
>  DEFS = @DEFS@
>  DEPDIR = @DEPDIR@
>  DSYMUTIL = @DSYMUTIL@
> diff --git a/bfd/config.bfd b/bfd/config.bfd
> index 7af481048db..f5f3b08e50b 100644
> --- a/bfd/config.bfd
> +++ b/bfd/config.bfd
> @@ -227,6 +227,40 @@ z8k*)		 targ_archs=bfd_z8k_arch ;;
>  *)		 targ_archs=bfd_${targ_cpu}_arch ;;
>  esac
>  
> +case "${targ}" in
> +  mipsisa64r6*)
> +    DEFAULT_ARCH=mips64r6
> +    ;;
> +  mipsisa64r5*)
> +    DEFAULT_ARCH=mips64r5
> +    ;;
> +  mipsisa64r3*)
> +    DEFAULT_ARCH=mips64r3
> +    ;;
> +  mipsisa64r2*)
> +    DEFAULT_ARCH=mips64r2
> +    ;;
> +  mipsisa64*)
> +    DEFAULT_ARCH=mips64
> +    ;;
> +  mipsisa32r6*)
> +    DEFAULT_ARCH=mips32r6
> +    ;;
> +  mipsisa32r5*)
> +    DEFAULT_ARCH=mips32r5
> +    ;;
> +  mipsisa32r3*)
> +    DEFAULT_ARCH=mips32r3
> +    ;;
> +  mipsisa32r2*)
> +    DEFAULT_ARCH=mips32r2
> +    ;;
> +  mipsisa32*)
> +    DEFAULT_ARCH=mips32
> +    ;;
> +  *)
> +    ;;
> +esac
>  
>  # WHEN ADDING ENTRIES TO THIS MATRIX:
>  #  Make sure that the left side always has two dashes.  Otherwise you
> @@ -941,11 +975,21 @@ case "${targ}" in
>      targ_defvec=mips_elf32_be_vec
>      targ_selvecs="mips_elf32_le_vec mips_elf64_be_vec mips_elf64_le_vec mips_ecoff_be_vec mips_ecoff_le_vec"
>      ;;
> -  mips64*el-*-linux*)
> +  mips*64*el-*-linux*-gnuabi64)
> +    targ_defvec=mips_elf64_trad_le_vec
> +    targ_selvecs="mips_elf32_ntrad_be_vec mips_elf32_ntrad_le_vec mips_elf32_trad_be_vec mips_elf32_trad_le_vec mips_elf64_trad_be_vec"
> +    want64=true
> +    ;;
> +  mips*64*-*-linux*-gnuabi64)
> +    targ_defvec=mips_elf64_trad_be_vec
> +    targ_selvecs="mips_elf32_ntrad_be_vec mips_elf32_ntrad_le_vec mips_elf32_trad_be_vec mips_elf32_trad_le_vec mips_elf64_trad_le_vec"
> +    want64=true
> +    ;;
> +  mips*64*el-*-linux*)
>      targ_defvec=mips_elf32_ntrad_le_vec
>      targ_selvecs="mips_elf32_ntrad_be_vec mips_elf32_trad_le_vec mips_elf32_trad_be_vec mips_elf64_trad_le_vec mips_elf64_trad_be_vec"
>      ;;
> -  mips64*-*-linux*)
> +  mips*64*-*-linux*)
>      targ_defvec=mips_elf32_ntrad_be_vec
>      targ_selvecs="mips_elf32_ntrad_le_vec mips_elf32_trad_be_vec mips_elf32_trad_le_vec mips_elf64_trad_be_vec mips_elf64_trad_le_vec"
>      ;;
> diff --git a/bfd/configure b/bfd/configure
> index 41d280ef461..3fc9aa6fdc2 100755
> --- a/bfd/configure
> +++ b/bfd/configure
> @@ -695,6 +695,7 @@ WARN_CFLAGS
>  REPORT_BUGS_TEXI
>  REPORT_BUGS_TO
>  PKGVERSION
> +DEFAULT_ARCH
>  DEBUGDIR
>  ENABLE_BFD_64_BIT_FALSE
>  ENABLE_BFD_64_BIT_TRUE
> @@ -13775,6 +13776,10 @@ do
>      fi
>  done
>  
> +if test -n "$DEFAULT_ARCH"; then
> +  TDEFINES="$TDEFINES -DDEFAULT_ARCH=\\\"${DEFAULT_ARCH}\\\""
> +fi
> +
>  
>  # This processing still needs to be done if we're to decide properly whether
>  # 64-bit support needs to be compiled in.  Currently, it will be included if
> diff --git a/bfd/configure.ac b/bfd/configure.ac
> index f044616f4d9..b432d7cf10f 100644
> --- a/bfd/configure.ac
> +++ b/bfd/configure.ac
> @@ -341,6 +341,10 @@ do
>  	TDEFINES="$TDEFINES $targ_cflags"
>      fi
>  done
> +
> +if test -n "$DEFAULT_ARCH"; then
> +  TDEFINES="$TDEFINES -DDEFAULT_ARCH=\\\"${DEFAULT_ARCH}\\\""
> +fi
>  AC_SUBST(TDEFINES)
>  
>  # This processing still needs to be done if we're to decide properly whether
> diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
> index d34a755807b..61f00981bfc 100644
> --- a/bfd/elfxx-mips.c
> +++ b/bfd/elfxx-mips.c
> @@ -47,6 +47,15 @@
>  
>  #include "hashtab.h"
>  
> +/* A table describing all ISA and its 32bit and 64bit version for best matching */
> +struct mips_eflags_32_64
> +{
> +  const char *name;
> +  flagword e_mips_arch;
> +  flagword e_mips_arch32;
> +  flagword e_mips_arch64;
> +};
> +
>  /* Types of TLS GOT entry.  */
>  enum mips_got_tls_type {
>    GOT_TLS_NONE,
> @@ -1306,6 +1315,28 @@ bfd_get_micromips_32 (const bfd *abfd, const bfd_byte *ptr)
>  #define TP_OFFSET 0x7000
>  #define DTP_OFFSET 0x8000
>  
> +/* A table describing all ISA and its 32bit and 64bit version for best matching */
> +__attribute__ ((unused))
> +static const struct mips_eflags_32_64 mips_eflags_32_64_table[] =
> +{
> +  { "mips1", E_MIPS_ARCH_1, E_MIPS_ARCH_1, E_MIPS_ARCH_3},
> +  { "mips2", E_MIPS_ARCH_2, E_MIPS_ARCH_2, E_MIPS_ARCH_3},
> +  { "mips3", E_MIPS_ARCH_3, E_MIPS_ARCH_2, E_MIPS_ARCH_3},
> +  { "mips4", E_MIPS_ARCH_3, E_MIPS_ARCH_2, E_MIPS_ARCH_4},
> +  { "mips5", E_MIPS_ARCH_5, E_MIPS_ARCH_2, E_MIPS_ARCH_5},
> +  { "mips32", E_MIPS_ARCH_32, E_MIPS_ARCH_32, E_MIPS_ARCH_64},
> +  { "mips32r2", E_MIPS_ARCH_32R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips32r3", E_MIPS_ARCH_32R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips32r5", E_MIPS_ARCH_32R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips32r6", E_MIPS_ARCH_32R6, E_MIPS_ARCH_32R6, E_MIPS_ARCH_64R6},
> +  { "mips64", E_MIPS_ARCH_64, E_MIPS_ARCH_32, E_MIPS_ARCH_64},
> +  { "mips64r2", E_MIPS_ARCH_64R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips64r3", E_MIPS_ARCH_64R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips64r5", E_MIPS_ARCH_64R2, E_MIPS_ARCH_32R2, E_MIPS_ARCH_64R2},
> +  { "mips64r6", E_MIPS_ARCH_64R6, E_MIPS_ARCH_32R6, E_MIPS_ARCH_64R6},
> +  { NULL, 0, 0, 0 }
> +};
> +
>  static bfd_vma
>  dtprel_base (struct bfd_link_info *info)
>  {
> @@ -12316,6 +12347,30 @@ _bfd_mips_elf_finish_dynamic_sections (bfd *output_bfd,
>  }
>  
>  
> +/* Get the E_MIPA_ARCH_?? value for the DEFAULT_ARCH
> +   The value of bits can be 32/64 or 0 (guess from DEFAULT_ARCH)
> +   */
> +static flagword mips_get_default_arch_eflags(int bits)
> +{
> +#ifdef DEFAULT_ARCH
> +  int i;
> +
> +  for (i = 0; mips_eflags_32_64_table[i].name; i++)
> +    if (strcasecmp (mips_eflags_32_64_table[i].name, DEFAULT_ARCH) != 0)
> +      continue;
> +    else if (bits == 32)
> +      return mips_eflags_32_64_table[i].e_mips_arch32;
> +    else if (bits == 64)
> +      return mips_eflags_32_64_table[i].e_mips_arch64;
> +    else if (bits == 0)
> +      return mips_eflags_32_64_table[i].e_mips_arch;
> +#endif
> +
> +  if (bits == 64)
> +    return E_MIPS_ARCH_3;
> +  return E_MIPS_ARCH_1;
> +}
> +
>  /* Set ABFD's EF_MIPS_ARCH and EF_MIPS_MACH flags.  */
>  
>  static void

One of my points in the previous review was that I don't think we should
change the behaviour for mipsisa32/64r2 and earlier (unless there's
a specific reason that I'm missing).  Starting out at the minimum
MIPS I for 32-bit ABIs and MIPS III for 64-bit ABIs seems like the
correct behaviour, with the architecture being bumped once code is
linked in.

E.g. I don't see any reason in principle why mipsisa64-elf-ld should
behave differently from mips64-elf-ld for the same set of input objects.
If all the input objects are MIPS III then the output should be too.
Similarly, I think -march=from-abi should select MIPS I/III even
for mipsisa64-elf.  That matches the GCC documentation:

  The special value @samp{from-abi} selects the
  most compatible architecture for the selected ABI (that is,
  @samp{mips1} for 32-bit ABIs and @samp{mips3} for 64-bit ABIs)@.

AIUI, the motivation for the change is that mipsisa32/64r6 is not
compatible with r2 and earlier, and so defaulting to MIPS I or MIPS III
isn't correct.  I think that makes r6 architectures a new base architecture
for MIPS 32/64 r6 and above.  E.g. if there was an r7 that was backwards-
compatible with r6, r7 should IMO use r6 as the default here, just like
MIPS IV toolchains use MIPS III as the default for 64-bit ABIs.

E.g. maybe we could have a MIPSR6_TOOLCHAIN_P that is true for
toolchains that are for r6+.  Then select:

  MIPSR6_TOOLCHAIN_P ? E_MIPS_ARCH_64R6 : E_MIPS_ARCH_3

and

  MIPSR6_TOOLCHAIN_P ? E_MIPS_ARCH_32R6 : E_MIPS_ARCH_1

I can see the argument for changing -march=from-abi for r6+ too,
but we should try to keep the GCC and GAS handling compatible.

Thanks,
Richard

> @@ -12327,9 +12382,11 @@ mips_set_isa_flags (bfd *abfd)
>      {
>      default:
>        if (ABI_N32_P (abfd) || ABI_64_P (abfd))
> -        val = E_MIPS_ARCH_3;
> +	 val = mips_get_default_arch_eflags(64);
> +      else if (ABI_O32_P (abfd))
> +	 val = mips_get_default_arch_eflags(32);
>        else
> -        val = E_MIPS_ARCH_1;
> +	 val = mips_get_default_arch_eflags(0);
>        break;
>  
>      case bfd_mach_mips3000:
> diff --git a/binutils/testsuite/binutils-all/mips/mips-note-2-n32.d b/binutils/testsuite/binutils-all/mips/mips-note-2-n32.d
> index c2a581858ed..5e24e7a115e 100644
> --- a/binutils/testsuite/binutils-all/mips/mips-note-2-n32.d
> +++ b/binutils/testsuite/binutils-all/mips/mips-note-2-n32.d
> @@ -1,4 +1,5 @@
>  #PROG: objcopy
> +#as: -n32
>  #readelf: --notes --wide
>  #objcopy: --merge-notes
>  #name: MIPS merge notes section (n32)
> diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
> index e911aaa904a..c906471eb92 100644
> --- a/gas/config/tc-mips.c
> +++ b/gas/config/tc-mips.c
> @@ -1422,6 +1422,15 @@ static int relaxed_micromips_16bit_branch_length (fragS *, asection *, int);
>  static int relaxed_micromips_32bit_branch_length (fragS *, asection *, int);
>  static void file_mips_check_options (void);
>  
> +/* A table describing all ISA and its 32bit and 64bit version for best matching */
> +
> +struct mips_isa_32_64
> +{
> +  int isa;
> +  int isa_32;
> +  int isa_64;
> +};
> +
>  /* Table and functions used to map between CPU/ISA names, and
>     ISA levels, and CPU numbers.  */
>  
> @@ -1439,6 +1448,7 @@ struct mips_cpu_info
>  static const struct mips_cpu_info *mips_parse_cpu (const char *, const char *);
>  static const struct mips_cpu_info *mips_cpu_info_from_isa (int);
>  static const struct mips_cpu_info *mips_cpu_info_from_arch (int);
> +static int mips_cpu_isa_32_64(int isa, int bits);
>  \f
>  /* Command-line options.  */
>  const char *md_shortopts = "O::g::G:";
> @@ -19979,6 +19989,28 @@ s_mips_mask (int reg_type)
>      }
>  }
>  
> +
> +/* A table describing all ISA and its 32bit and 64bit version for best matching */
> +static const struct mips_isa_32_64 mips_isa_32_64_table[] =
> +{
> +  { ISA_MIPS1, ISA_MIPS1, ISA_MIPS3 },
> +  { ISA_MIPS2, ISA_MIPS2, ISA_MIPS3 },
> +  { ISA_MIPS3, ISA_MIPS2, ISA_MIPS3 },
> +  { ISA_MIPS4, ISA_MIPS2, ISA_MIPS4 },
> +  { ISA_MIPS5, ISA_MIPS2, ISA_MIPS5 },
> +  { ISA_MIPS32, ISA_MIPS32, ISA_MIPS64 },
> +  { ISA_MIPS32R2, ISA_MIPS32R2, ISA_MIPS64R2 },
> +  { ISA_MIPS32R3, ISA_MIPS32R3, ISA_MIPS64R3 },
> +  { ISA_MIPS32R5, ISA_MIPS32R5, ISA_MIPS64R5 },
> +  { ISA_MIPS32R6, ISA_MIPS32R6, ISA_MIPS64R6 },
> +  { ISA_MIPS64, ISA_MIPS32, ISA_MIPS64 },
> +  { ISA_MIPS64R2, ISA_MIPS32R2, ISA_MIPS64R2 },
> +  { ISA_MIPS64R3, ISA_MIPS32R3, ISA_MIPS64R3 },
> +  { ISA_MIPS64R5, ISA_MIPS32R5, ISA_MIPS64R5 },
> +  { ISA_MIPS64R6, ISA_MIPS32R6, ISA_MIPS64R6 },
> +  { 0, 0, 0 }
> +};
> +
>  /* A table describing all the processors gas knows about.  Names are
>     matched in the order listed.
>  
> @@ -20223,6 +20255,9 @@ static const struct mips_cpu_info *
>  mips_parse_cpu (const char *option, const char *cpu_string)
>  {
>    const struct mips_cpu_info *p;
> +  const struct mips_cpu_info *default_cpu;
> +  int default_isa32 = ISA_MIPS1;
> +  int default_isa64 = ISA_MIPS3;
>  
>    /* 'from-abi' selects the most compatible architecture for the given
>       ABI: MIPS I for 32-bit ABIs and MIPS III for 64-bit ABIs.  For the
> @@ -20236,19 +20271,26 @@ mips_parse_cpu (const char *option, const char *cpu_string)
>       'mips64', just as we did in the days before 'from-abi'.  */
>    if (strcasecmp (cpu_string, "from-abi") == 0)
>      {
> +	for (default_cpu = mips_cpu_info_table; default_cpu->name != 0; default_cpu++)
> +	  if (mips_matching_cpu_name_p (default_cpu->name, MIPS_CPU_STRING_DEFAULT))
> +	    {
> +	      default_isa32 = mips_cpu_isa_32_64 (default_cpu->isa, 32);
> +	      default_isa64 = mips_cpu_isa_32_64 (default_cpu->isa, 64);
> +	      break;
> +	    }
>        if (ABI_NEEDS_32BIT_REGS (mips_abi))
> -	return mips_cpu_info_from_isa (ISA_MIPS1);
> +	return mips_cpu_info_from_isa (default_isa32);
>  
>        if (ABI_NEEDS_64BIT_REGS (mips_abi))
> -	return mips_cpu_info_from_isa (ISA_MIPS3);
> +	return mips_cpu_info_from_isa (default_isa64);
>  
>        if (file_mips_opts.gp >= 0)
>  	return mips_cpu_info_from_isa (file_mips_opts.gp == 32
> -				       ? ISA_MIPS1 : ISA_MIPS3);
> +				       ? default_isa32 : default_isa64);
>  
>        return mips_cpu_info_from_isa (MIPS_DEFAULT_64BIT
> -				     ? ISA_MIPS3
> -				     : ISA_MIPS1);
> +				     ? default_isa64
> +				     : default_isa32);
>      }
>  
>    /* 'default' has traditionally been a no-op.  Probably not very useful.  */
> @@ -20263,6 +20305,24 @@ mips_parse_cpu (const char *option, const char *cpu_string)
>    return 0;
>  }
>  
> +/* Return the best matching 32bit/64bit ISA of a ISA, according the table
> +   mips_isa_32_64_table */
> +static int
> +mips_cpu_isa_32_64(int isa, int bits)
> +{
> +  int i;
> +
> +  for (i = 0; mips_isa_32_64_table[i].isa != 0; i++)
> +    if (isa != mips_isa_32_64_table[i].isa)
> +      continue;
> +    else if (bits == 32)
> +      return mips_isa_32_64_table[i].isa_32;
> +    else if (bits == 64)
> +      return mips_isa_32_64_table[i].isa_64;
> +
> +  return 0;
> +}
> +
>  /* Return the canonical processor information for ISA (a member of the
>     ISA_MIPS* enumeration).  */
>  
> diff --git a/gas/configure b/gas/configure
> index b56836998ef..11b0a56bbd4 100755
> --- a/gas/configure
> +++ b/gas/configure
> @@ -12201,6 +12201,21 @@ _ACEOF
>  	    as_fn_error $? "$target_cpu isn't a supported MIPS CPU name" "$LINENO" 5
>  	    ;;
>  	esac
> +	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for default configuration of --with-arch" >&5
> +$as_echo_n "checking for default configuration of --with-arch... " >&6; }
> +	if test "x${with_arch}" != x; then
> +	  case ${with_arch} in
> +	    mips1 | mips2 | mips32 | mips32r2 | mips32r3 | mips32r5 | mips32r6 | \
> +	    mips3 | mips4 | mips5 | mips64 | mips64r2 | mips64r3 | mips64r5 | mips64r6)
> +	      mips_cpu=${with_arch}
> +	      ;;
> +	    *)
> +	      as_fn_error $? "This kind of arch name does *NOT* exist!" "$LINENO" 5
> +	      ;;
> +	  esac
> +	fi
> +	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_arch" >&5
> +$as_echo "$with_arch" >&6; }
>  	# See whether it's appropriate to set E_MIPS_ABI_O32 for o32
>  	# binaries.  It's a GNU extension that some OSes don't understand.
>  	case ${target} in
> @@ -12223,7 +12238,10 @@ _ACEOF
>  	esac
>  	# Decide which ABI to target by default.
>  	case ${target} in
> -	  mips64*-linux* | mips-sgi-irix6* | mips64*-freebsd* \
> +	  mips*64*-linux-gnuabi64)
> +	    mips_default_abi=N64_ABI
> +	    ;;
> +	  mips*64*-linux* | mips-sgi-irix6* | mips64*-freebsd* \
>  	  | mips64*-kfreebsd*-gnu | mips64*-ps2-elf*)
>  	    mips_default_abi=N32_ABI
>  	    ;;
> diff --git a/gas/configure.ac b/gas/configure.ac
> index 6a68fd7c4e6..a126a3fda5d 100644
> --- a/gas/configure.ac
> +++ b/gas/configure.ac
> @@ -370,6 +370,19 @@ changequote([,])dnl
>  	    AC_MSG_ERROR($target_cpu isn't a supported MIPS CPU name)
>  	    ;;
>  	esac
> +	AC_MSG_CHECKING(for default configuration of --with-arch)
> +	if test "x${with_arch}" != x; then
> +	  case ${with_arch} in
> +	    mips1 | mips2 | mips32 | mips32r2 | mips32r3 | mips32r5 | mips32r6 | \
> +	    mips3 | mips4 | mips5 | mips64 | mips64r2 | mips64r3 | mips64r5 | mips64r6)
> +	      mips_cpu=${with_arch}
> +	      ;;
> +	    *)
> +	      AC_MSG_ERROR(This kind of arch name does *NOT* exist!)
> +	      ;;
> +	  esac
> +	fi
> +	AC_MSG_RESULT($with_arch)
>  	# See whether it's appropriate to set E_MIPS_ABI_O32 for o32
>  	# binaries.  It's a GNU extension that some OSes don't understand.
>  	case ${target} in
> @@ -392,7 +405,10 @@ changequote([,])dnl
>  	esac
>  	# Decide which ABI to target by default.
>  	case ${target} in
> -	  mips64*-linux* | mips-sgi-irix6* | mips64*-freebsd* \
> +	  mips*64*-linux-gnuabi64)
> +	    mips_default_abi=N64_ABI
> +	    ;;
> +	  mips*64*-linux* | mips-sgi-irix6* | mips64*-freebsd* \
>  	  | mips64*-kfreebsd*-gnu | mips64*-ps2-elf*)
>  	    mips_default_abi=N32_ABI
>  	    ;;
> diff --git a/gold/configure.tgt b/gold/configure.tgt
> index 4b54e08d27f..ef47ce079f1 100644
> --- a/gold/configure.tgt
> +++ b/gold/configure.tgt
> @@ -153,6 +153,13 @@ aarch64*-*)
>   targ_big_endian=false
>   targ_extra_big_endian=true
>   ;;
> +mips*64*el*-*-*|mips*64*le*-*-*)
> + targ_obj=mips
> + targ_machine=EM_MIPS_RS3_LE
> + targ_size=64
> + targ_big_endian=false
> + targ_extra_big_endian=true
> + ;;
>  mips*el*-*-*|mips*le*-*-*)
>   targ_obj=mips
>   targ_machine=EM_MIPS_RS3_LE
> @@ -160,6 +167,13 @@ mips*el*-*-*|mips*le*-*-*)
>   targ_big_endian=false
>   targ_extra_big_endian=true
>   ;;
> +mips*64*-*-*)
> + targ_obj=mips
> + targ_machine=EM_MIPS
> + targ_size=64
> + targ_big_endian=true
> + targ_extra_big_endian=false
> + ;;
>  mips*-*-*)
>   targ_obj=mips
>   targ_machine=EM_MIPS
> diff --git a/ld/configure.tgt b/ld/configure.tgt
> index 34c9d67c365..4a71f679e29 100644
> --- a/ld/configure.tgt
> +++ b/ld/configure.tgt
> @@ -580,11 +580,19 @@ mips*-*-vxworks*)	targ_emul=elf32ebmipvxworks
>  			;;
>  mips*-*-windiss)	targ_emul=elf32mipswindiss
>  			;;
> -mips64*el-*-linux-*)	targ_emul=elf32ltsmipn32
> +mips*64*el-*-linux-gnuabi64)	targ_emul=elf64ltsmip
> +			targ_extra_emuls="elf32btsmipn32 elf32ltsmipn32 elf32ltsmip elf32btsmip elf64btsmip"
> +			targ_extra_libpath=$targ_extra_emuls
> +			;;
> +mips*64*el-*-linux-*)	targ_emul=elf32ltsmipn32
>  			targ_extra_emuls="elf32btsmipn32 elf32ltsmip elf32btsmip elf64ltsmip elf64btsmip"
>  			targ_extra_libpath=$targ_extra_emuls
>  			;;
> -mips64*-*-linux-*)	targ_emul=elf32btsmipn32
> +mips*64*-*-linux-gnuabi64)	targ_emul=elf64btsmip
> +			targ_extra_emuls="elf32btsmipn32 elf32ltsmipn32 elf32btsmip elf32ltsmip elf64ltsmip"
> +			targ_extra_libpath=$targ_extra_emuls
> +			;;
> +mips*64*-*-linux-*)	targ_emul=elf32btsmipn32
>  			targ_extra_emuls="elf32ltsmipn32 elf32btsmip elf32ltsmip elf64btsmip elf64ltsmip"
>  			targ_extra_libpath=$targ_extra_emuls
>  			;;