[PATCH] Rework to minimize and eventually eliminate RTEMS use of bsp_specs

Amaan Cheval amaan.cheval at gmail.com
Thu May 17 19:29:34 UTC 2018


Hey!

Thanks so much for sharing this, it's quite useful to put your earlier
email[1] about minimzing the bsp_specs in context.

>From looking ahead a bit without testing (still compiling), the patch
may need an ENDFILE_SPEC definition as well for "crtend.o" (it defines
__TMC_END__ which crtbegin.o has left undefined for eg.) and possibly
"crtn.o", at least to eliminate the x86_64 port's bsp_specs entirely
(see here[2]).

I've also left some comments inline below.

+1 on upstreaming this into GCC (making sure it also backports to 7.3
for simplicity, so we don't need to write a 7.3-specific patch for the
RSB as well) with a few additons (at least for the x86_64 target, to
try to have an empty bsp_specs to begin with).

[1] https://lists.rtems.org/pipermail/devel/2018-May/021430.html
[2] https://github.com/AmaanC/rtems-gsoc18/blob/ac/daily-01-compile-stub/bsps/x86_64/amd64/start/bsp_specs

On Wed, May 16, 2018 at 8:46 PM, Joel Sherrill <joel at rtems.org> wrote:
> ---
>  gcc/config.gcc                |  2 +-
>  gcc/config/arm/rtems.h        |  4 ++++
>  gcc/config/bfin/rtems.h       |  4 ++++
>  gcc/config/i386/rtemself.h    |  6 +++++-
>  gcc/config/i386/rtemself64.h  | 39 +++++++++++++++++++++++++++++++++++++++
>  gcc/config/m68k/rtemself.h    |  4 ++++
>  gcc/config/microblaze/rtems.h |  4 ++++
>  gcc/config/mips/rtems.h       |  4 ++++
>  gcc/config/moxie/rtems.h      |  4 ++++
>  gcc/config/nios2/rtems.h      |  4 ++++
>  gcc/config/riscv/rtems.h      |  4 ++++
>  gcc/config/rs6000/rtems.h     |  5 +++++
>  gcc/config/rtems.h            |  6 +++++-
>  gcc/config/sh/rtems.h         |  4 ++++
>  gcc/config/sh/rtemself.h      |  4 ++++
>  gcc/config/sparc/rtemself.h   |  4 ++++
>  gcc/config/v850/rtems.h       |  4 ++++
>  17 files changed, 103 insertions(+), 3 deletions(-)
>  create mode 100644 gcc/config/i386/rtemself64.h
>
> diff --git a/gcc/config.gcc b/gcc/config.gcc
> index d509800..de27e5c 100644
> --- a/gcc/config.gcc
> +++ b/gcc/config.gcc
> @@ -1499,7 +1499,7 @@ x86_64-*-elf*)
>         tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h newlib-stdint.h i386/i386elf.h i386/x86-64.h"
>         ;;
>  x86_64-*-rtems*)
> -       tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h newlib-stdint.h i386/i386elf.h i386/x86-64.h i386/rtemself.h rtems.h"
> +       tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h newlib-stdint.h i386/i386elf.h i386/x86-64.h i386/rtemself64.h"

In rebasing with upstream, this commit must have silently mistakenly
also dropped rtems.h (which my patch earlier added to support the
-qrtems, -qnolinkcmds, etc. flags).

>         ;;
>  i[34567]86-*-rdos*)
>      tm_file="${tm_file} i386/unix.h i386/att.h dbxelf.h elfos.h newlib-stdint.h i386/i386elf.h i386/rdos.h"
> diff --git a/gcc/config/arm/rtems.h b/gcc/config/arm/rtems.h
> index 1123f4a..e79ce90 100644
> --- a/gcc/config/arm/rtems.h
> +++ b/gcc/config/arm/rtems.h
> @@ -34,3 +34,7 @@
>      } while (0)
>
>  #define ARM_DEFAULT_SHORT_ENUMS false
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/bfin/rtems.h b/gcc/config/bfin/rtems.h
> index 6a9a41f..28a69b9 100644
> --- a/gcc/config/bfin/rtems.h
> +++ b/gcc/config/bfin/rtems.h
> @@ -31,3 +31,7 @@
>        builtin_assert ("system=rtems");         \
>      }                                          \
>    while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/i386/rtemself.h b/gcc/config/i386/rtemself.h
> index 65e8dad..3a09354 100644
> --- a/gcc/config/i386/rtemself.h
> +++ b/gcc/config/i386/rtemself.h
> @@ -1,4 +1,4 @@
> -/* Definitions for rtems targeting an ix86 using ELF.
> +/* Definitions for rtems targeting an x86_64 using ELF.

I think you meant to have this comment in rtemself64.h, which says
ix86 currently?

>     Copyright (C) 1996-2018 Free Software Foundation, Inc.
>     Contributed by Joel Sherrill (joel at OARcorp.com).
>
> @@ -33,3 +33,7 @@
>         builtin_assert ("system=rtems");        \
>      }                                          \
>    while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crtbegin.o%s}"
> diff --git a/gcc/config/i386/rtemself64.h b/gcc/config/i386/rtemself64.h
> new file mode 100644
> index 0000000..34e5937
> --- /dev/null
> +++ b/gcc/config/i386/rtemself64.h
> @@ -0,0 +1,39 @@
> +/* Definitions for rtems targeting an ix86 using ELF.

See above.

> +   Copyright (C) 1996-2018 Free Software Foundation, Inc.
> +   Contributed by Joel Sherrill (joel at OARcorp.com).
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC 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 General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +/* Specify predefined symbols in preprocessor.  */
> +
> +#define TARGET_OS_CPP_BUILTINS()               \
> +  do                                           \
> +    {                                          \
> +       builtin_define ("__rtems__");           \
> +       builtin_define ("__USE_INIT_FINI__");   \
> +       builtin_assert ("system=rtems");        \
> +    }                                          \
> +  while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/m68k/rtemself.h b/gcc/config/m68k/rtemself.h
> index e18a06e..6f31aa5 100644
> --- a/gcc/config/m68k/rtemself.h
> +++ b/gcc/config/m68k/rtemself.h
> @@ -36,3 +36,7 @@
>         builtin_assert ("system=rtems");        \
>      }                                          \
>    while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/microblaze/rtems.h b/gcc/config/microblaze/rtems.h
> index 5f23321..fc8914c 100644
> --- a/gcc/config/microblaze/rtems.h
> +++ b/gcc/config/microblaze/rtems.h
> @@ -35,3 +35,7 @@
>    %{mbig-endian:-EB --oformat=elf32-microblaze} \
>    %{mlittle-endian:-EL --oformat=elf32-microblazeel} \
>    %{mxl-gp-opt:%{G*}} %{!mxl-gp-opt: -G 0}"
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/mips/rtems.h b/gcc/config/mips/rtems.h
> index 66e00bf..6e96853 100644
> --- a/gcc/config/mips/rtems.h
> +++ b/gcc/config/mips/rtems.h
> @@ -37,3 +37,7 @@ do {                                  \
>   */
>  #undef MIPS_DEFAULT_GVALUE
>  #define MIPS_DEFAULT_GVALUE 0
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/moxie/rtems.h b/gcc/config/moxie/rtems.h
> index bc28d6e..6c79063 100644
> --- a/gcc/config/moxie/rtems.h
> +++ b/gcc/config/moxie/rtems.h
> @@ -38,3 +38,7 @@
>  #undef PTRDIFF_TYPE
>  #undef WCHAR_TYPE
>  #undef WCHAR_TYPE_SIZE
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/nios2/rtems.h b/gcc/config/nios2/rtems.h
> index b4a6082..f6eedf6 100644
> --- a/gcc/config/nios2/rtems.h
> +++ b/gcc/config/nios2/rtems.h
> @@ -37,3 +37,7 @@ do {                                    \
>
>     This is done so RTEMS targets have Thread Local Storage like Linux.  */
>  #define TARGET_LINUX_ABI 1
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/riscv/rtems.h b/gcc/config/riscv/rtems.h
> index 231b6a0..a9d1e01 100644
> --- a/gcc/config/riscv/rtems.h
> +++ b/gcc/config/riscv/rtems.h
> @@ -29,3 +29,7 @@
>         builtin_define ("__USE_INIT_FINI__");   \
>         builtin_assert ("system=rtems");        \
>      } while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/rs6000/rtems.h b/gcc/config/rs6000/rtems.h
> index 54ddcb4..20a4ffa 100644
> --- a/gcc/config/rs6000/rtems.h
> +++ b/gcc/config/rs6000/rtems.h
> @@ -72,6 +72,11 @@
>      }                                                  \
>    while (0)
>
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} ecrti.o%s crtbegin.o%s}"
> +
>  /* Copy and paste from linux64.h and freebsd64.h */
>  #undef RELOCATABLE_NEEDS_FIXUP
>  #define RELOCATABLE_NEEDS_FIXUP \
> diff --git a/gcc/config/rtems.h b/gcc/config/rtems.h
> index dcea95c..9a0619c 100644
> --- a/gcc/config/rtems.h
> +++ b/gcc/config/rtems.h
> @@ -30,11 +30,15 @@
>   * Dummy start/end specification to let linker work as
>   * needed by autoconf scripts using this compiler.
>   */
> +#if 0
>  #undef STARTFILE_SPEC
> -#define STARTFILE_SPEC "crt0.o%s"
> +#define STARTFILE_SPEC "%{!qrtems: crt0.o%s}"
> +#endif
>
> +#if 0
>  #undef ENDFILE_SPEC
>  #define ENDFILE_SPEC   ""
> +#endif
>
>  /*
>   * Some targets do not set up LIB_SPECS, override it, here.
> diff --git a/gcc/config/sh/rtems.h b/gcc/config/sh/rtems.h
> index d2f2b2a..f699151 100644
> --- a/gcc/config/sh/rtems.h
> +++ b/gcc/config/sh/rtems.h
> @@ -29,3 +29,7 @@
>    builtin_define( "__rtems__" );               \
>    builtin_assert( "system=rtems" );            \
>  } while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/sh/rtemself.h b/gcc/config/sh/rtemself.h
> index 6a67b49..85f26b0 100644
> --- a/gcc/config/sh/rtemself.h
> +++ b/gcc/config/sh/rtemself.h
> @@ -29,3 +29,7 @@
>    builtin_define( "__rtems__" );               \
>    builtin_assert( "system=rtems" );            \
>  } while (0)
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/sparc/rtemself.h b/gcc/config/sparc/rtemself.h
> index e4b52d8..7c5bf43 100644
> --- a/gcc/config/sparc/rtemself.h
> +++ b/gcc/config/sparc/rtemself.h
> @@ -38,3 +38,7 @@
>
>  /* Use the default */
>  #undef LINK_GCC_C_SEQUENCE_SPEC
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> diff --git a/gcc/config/v850/rtems.h b/gcc/config/v850/rtems.h
> index b20b2c3..1b56649 100644
> --- a/gcc/config/v850/rtems.h
> +++ b/gcc/config/v850/rtems.h
> @@ -39,3 +39,7 @@
>  %{!mv850es:%{!mv850e1:%{mv*:-mv%*}} \
>  %{m8byte-align:-m8byte-align} \
>  %{mgcc-abi:-mgcc-abi}}"
> +
> +#undef STARTFILE_SPEC
> +#define STARTFILE_SPEC "\
> +%{!nostdlib: %{!qrtems: crt0.o%s} crti.o%s crtbegin.o%s}"
> --
> 1.8.3.1
>
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