Re: [gold] First patch for aarch64 backend

[Yufeng Zhang <yufengzhangdev at gmail dot com>]

On 26 June 2014 00:46, Jing Yu <jingyu@google.com> wrote:
>
> Hi,
>
> We start to work on gold aarch64 backend. Here is the first patch.
> This patch is just a skeleton which almost does nothing.
> The change that enables gold for aarch64 in top level configure was
> removed from this patch.
>
> Tested:
> 1) On x86_64,
> ${binutils}/configure --build=x86_64-unknown-linux-gnu
> --host=x86_64-unknown-linux-gnu --target=x86_64-unknown-linux-gnu
> --enable-plugins --disable-multilib --disable-nls --enable-threads
> --enable-gold=default --enable-targets=all
> $make all-gold
>
> Also built with -O1 and -O0.
>
> 2) On aarch64,
> gcc version 4.8.2 (Ubuntu/Linaro 4.8.2-19ubuntu1)
> $ ../binutils-gdb/configure --enable-plugins --disable-multilib
> --disable-nls --enable-threads --enable-gold=default
> --enable-targets=all
> $make all-gold
> Also built with -O1 and -O0.
>
> The generated native gold/ld-new is able to read hello.o and libc.so.
>
> Thanks,
> Jing
>
> diff --git a/elfcpp/aarch64.h b/elfcpp/aarch64.h
> new file mode 100644
> index 0000000..09bc498
> --- /dev/null
> +++ b/elfcpp/aarch64.h
> @@ -0,0 +1,183 @@
> +// aarch64.h -- ELF definitions specific to AARCH64  -*- C++ -*-
> +
> +// Copyright (C) 2012-2014 Free Software Foundation, Inc.
> +// Written by Jing Yu (jingyu@google.com)
> +
> +// This file is part of elfcpp.
> +
> +// This program is free software; you can redistribute it and/or
> +// modify it under the terms of the GNU Library General Public License
> +// as published by the Free Software Foundation; either version 2, or
> +// (at your option) any later version.
> +
> +// In addition to the permissions in the GNU Library General Public
> +// License, the Free Software Foundation gives you unlimited
> +// permission to link the compiled version of this file into
> +// combinations with other programs, and to distribute those
> +// combinations without any restriction coming from the use of this
> +// file.  (The Library Public License restrictions do apply in other
> +// respects; for example, they cover modification of the file, and
> +/// distribution when not linked into a combined executable.)
> +
> +// This program is distributed in the hope that it will be useful, but
> +// WITHOUT ANY WARRANTY; without even the implied warranty of
> +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +// Library General Public License for more details.
> +
> +// You should have received a copy of the GNU Library General Public
> +// License along with this program; if not, write to the Free Software
> +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
> +// 02110-1301, USA.
> +
> +#ifndef ELFCPP_AARCH64_H
> +#define ELFCPP_AARCH64_H
> +
> +namespace elfcpp
> +{
> +
> +// The relocation type information is taken from:
> +//
> +//   ELF for the ARM 64-bit Architecture (AArch64)
> +//   Document number: ARM IHI 0056B, current through AArch64 ABI release 1.0
> +//   Date of Issue: 22nd May, 2013
> +//

Is there a particular reason that you didnât choose the ABI release
1.1 which has the support for ELF32, including the ELF32 relocation
codes?

> +
> +enum
> +{
> +  // Null relocation codes
> +  R_AARCH64_NONE = 0, // None
> +  withdrawn = 256, // Treat as R_AARCH64_NONE
> +
> +  // Static relocations
> +  R_AARCH64_ABS64 = 257, // S + A
> +  R_AARCH64_ABS32 = 258, // S + A
> +  R_AARCH64_ABS16 = 259, // S + A
> +  R_AARCH64_PREL64 = 260, // S + A - P
> +  R_AARCH64_PREL32 = 261, // S + A - P
> +  R_AARCH64_PREL16 = 262, // S + A - P
> +  R_AARCH64_MOVW_UABS_G0 = 263, // S + A
> +  R_AARCH64_MOVW_UABS_G0_NC = 264, // S + A
> +  R_AARCH64_MOVW_UABS_G1 = 265, // S + A

[snip]

> diff --git a/gold/configure.tgt b/gold/configure.tgt
> index 93d622d..eaf164b 100644
> --- a/gold/configure.tgt
> +++ b/gold/configure.tgt
> @@ -144,6 +144,14 @@ arm*-*-*)
>   targ_big_endian=false
>   targ_extra_big_endian=true
>   ;;
> +aarch64-*)

I think you'll need aarch64*-* in order to support targ_extra_size=32
and targ_extra_big_endian=true.

Yufeng