Hi!
Sorry for the late reply.
On Fri, 28 Apr 2017 18:06:39 +0100, Andrew Stubbs <a...@codesourcery.com> wrote:
> 3. Add -mgpu option and corresponding --with-gpu. I've deliberately used
> "gpu" instead of "cpu" because I want offloading compilers to be able to
> say "-mcpu=foo -foffload=-mgpu=bar", or even have the host compiler just
> understand -mgpu and DTRT.
I'm not sure I understand your last statement, or the intentions behind
it.
How would the host compiler (be able to) understand (or, disambiguate)
"-mgpu=[...]" in the (default) case of several offloading targets having
been configured? I think it holds that "-m[...]" etc. must/can always
only apply to the current target (or "host", in "offloading speak").
And then, I don't have any strong opinion, but I don't see why a new
"-mgpu" option is preferable to using the existing "-march" etc. in
"-foffload=[...]". For example, you can already now do things like
(exemplary):
-march=x86_64 -foffload=-march=generic -foffload=nvptx-none=-march=cc_50
-foffload=gcn=-march=carrizo
^ target-specific ^ offload-target-specific, unless overridden... ^ ...
here... ^ ..., and here
Likewise for the new "--with-gpu=[...]" vs. the existing
"--with-arch=[...]", where again I would, unless there is a specific
reason (that I didn't understand here), default to using the existing
option names instead of introducing new ones.
Grüße
Thomas
> commit 5058457b0fa07865b366832828e74a53e5bd2964
> Author: Andrew Stubbs <a...@codesourcery.com>
> Date: Fri Apr 28 14:37:25 2017 +0100
>
> Add -mgpu
>
> 2017-04-28 Andrew Stubbs <a...@codesourcery.com>
>
> gcc/
> * config.gcc (amdgcn): Remove --with-arch and --with-tune.
> Add --with-gpu, and set default to "carrizo"
> (add_defaults): Add "gpu".
> * config/gcn/gcn-opts.h: New file.
> * config/gcn/gcn.c (output_file_start): Switch to HSACO version
> 2 and auto-detection of GPU type (from -mcpu).
> (gcn_arch, gcn_tune): Remove.
> * config/gcn/gcn.h: Include gcn-opts.h.
> (enum processor_type): Move to gcn-opts.h.
> (LIBGCC_SPEC, ASM_SPEC, LINK_SPEC): Define.
> (gcn_arch, gcn_tune): Remove.
> (OPTION_DEFAULT_SPECS): Remove "arch" and "tune"; add "gpu".
> * config/gcn/gcn.opt: Include gcn-opts.h.
> (gpu_type): New Enum.
> (mgpu): New option.
>
> diff --git a/gcc/config.gcc b/gcc/config.gcc
> index 4a77b66..b1df533 100644
> --- a/gcc/config.gcc
> +++ b/gcc/config.gcc
> @@ -3901,20 +3901,20 @@ case "${target}" in
> ;;
>
> amdgcn-*-*)
> - supported_defaults="arch tune"
> + supported_defaults="gpu"
>
> - for which in arch tune; do
> - eval "val=\$with_$which"
> - case ${val} in
> - "" | fiji)
> - # OK
> - ;;
> - *)
> - echo "Unknown cpu used in --with-$which=$val."
> 1>&2
> - exit 1
> - ;;
> - esac
> - done
> + case "$with_gpu" in
> + "")
> + with_gpu=carrizo
> + ;;
> + carrizo | fiji)
> + # OK
> + ;;
> + *)
> + echo "Unknown gpu used in --with-gpu=$val." 1>&2
> + exit 1
> + ;;
> + esac
> ;;
>
> hppa*-*-*)
> @@ -4646,7 +4646,7 @@ case ${target} in
> esac
>
> t=
> -all_defaults="abi cpu cpu_32 cpu_64 arch arch_32 arch_64 tune tune_32
> tune_64 schedule float mode fpu nan fp_32 odd_spreg_32 divide llsc mips-plt
> synci tls lxc1-sxc1 madd4"
> +all_defaults="abi cpu cpu_32 cpu_64 arch arch_32 arch_64 tune tune_32
> tune_64 schedule float mode fpu nan fp_32 odd_spreg_32 divide llsc mips-plt
> synci tls lxc1-sxc1 madd4 gpu"
> for option in $all_defaults
> do
> eval "val=\$with_"`echo $option | sed s/-/_/g`
> diff --git a/gcc/config/gcn/gcn-opts.h b/gcc/config/gcn/gcn-opts.h
> new file mode 100644
> index 0000000..d0586d6
> --- /dev/null
> +++ b/gcc/config/gcn/gcn-opts.h
> @@ -0,0 +1,27 @@
> +/* Copyright (C) 2016-2017 Free Software Foundation, Inc.
> +
> + This file 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 of the License, or (at your option)
> + any later version.
> +
> + This file 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.
> +
> + You should have received a copy of the GNU General Public License
> + along with GCC; see the file COPYING3. If not see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef GCN_OPTS_H
> +#define GCN_OPTS_H
> +
> +/* Which processor to generate code or schedule for. */
> +enum processor_type
> +{
> + PROCESSOR_CARRIZO,
> + PROCESSOR_FIJI
> +};
> +
> +#endif
> diff --git a/gcc/config/gcn/gcn.c b/gcc/config/gcn/gcn.c
> index eb6edd8..f378bf8 100644
> --- a/gcc/config/gcn/gcn.c
> +++ b/gcc/config/gcn/gcn.c
> @@ -60,11 +60,6 @@
> /* This file should be included last. */
> #include "target-def.h"
>
> -/* Which instruction set architecture to use. */
> -int gcn_arch;
> -/* Which cpu are we tuning for. */
> -int gcn_tune;
> -
> static REAL_VALUE_TYPE dconst4, dconst1over2pi;
> static bool ext_gcn_constants_init = 0;
>
> @@ -2006,8 +2001,8 @@ static void
> output_file_start (void)
> {
> fprintf (asm_out_file, "\t.hsatext\n");
> - fprintf (asm_out_file, "\t.hsa_code_object_version 1,0\n");
> - fprintf (asm_out_file, "\t.hsa_code_object_isa
> 8,0,1,\"AMD\",\"AMDGPU\"\n");
> + fprintf (asm_out_file, "\t.hsa_code_object_version 2,0\n");
> + fprintf (asm_out_file, "\t.hsa_code_object_isa\n"); // Autodetect
> fprintf (asm_out_file, "\t.section\t.AMDGPU.config\n");
> fprintf (asm_out_file, "\t.hsatext\n");
> }
> diff --git a/gcc/config/gcn/gcn.h b/gcc/config/gcn/gcn.h
> index 903022f..a3f9463 100644
> --- a/gcc/config/gcn/gcn.h
> +++ b/gcc/config/gcn/gcn.h
> @@ -14,25 +14,28 @@
> along with GCC; see the file COPYING3. If not see
> <http://www.gnu.org/licenses/>. */
>
> +#include "config/gcn/gcn-opts.h"
> +
>
> /* FIXME */
> #define TARGET_CPU_CPP_BUILTINS()
>
> -/* Which processor to generate code or schedule for. */
> -enum processor_type
> -{
> - PROCESSOR_CARRIZO,
> -};
> +/* Temporarily disable libgcc until one actually exists. */
> +#undef LIBGCC_SPEC
> +#define LIBGCC_SPEC ""
> +
> +/* Use LLVM assembler options. */
> +#undef ASM_SPEC
> +#define ASM_SPEC "-triple=amdgcn--amdhsa %{mgpu=*:-mcpu=%*} -filetype=obj"
>
> -extern GTY(()) int gcn_arch;
> -extern GTY(()) int gcn_tune;
> +/* Default to relocatable executables as output. */
> +#undef LINK_SPEC
> +#define LINK_SPEC "-shared"
>
> /* Support for a compile-time default architecture and tuning. The rules
> are:
> - --with-arch is ignored if -march is specified.
> - --with-tune is ignored if -mtune is specified. */
> + --with-gpu is ignored if -mgpu is specified. */
> #define OPTION_DEFAULT_SPECS \
> - {"arch", "%{!march=*:-march=%(VALUE)}" }, \
> - {"tune", "%{!mtune=*:-mtune=%(VALUE)}" }
> + {"gpu", "%{!mgpu=*:-mgpu=%(VALUE)}"}
>
> /* Default target_flags if no switches specified. */
> #ifndef TARGET_DEFAULT
> diff --git a/gcc/config/gcn/gcn.opt b/gcc/config/gcn/gcn.opt
> index 8fc02b7..77f0ef0 100644
> --- a/gcc/config/gcn/gcn.opt
> +++ b/gcc/config/gcn/gcn.opt
> @@ -17,3 +17,20 @@
> ; You should have received a copy of the GNU General Public License
> ; along with GCC; see the file COPYING3. If not see
> ; <http://www.gnu.org/licenses/>.
> +
> +HeaderInclude
> +config/gcn/gcn-opts.h
> +
> +Enum
> +Name(gpu_type) Type(enum processor_type)
> +GCN GPU type to use:
> +
> +EnumValue
> +Enum(gpu_type) String(carrizo) Value(PROCESSOR_CARRIZO)
> +
> +EnumValue
> +Enum(gpu_type) String(fiji) Value(PROCESSOR_FIJI)
> +
> +mgpu=
> +Target RejectNegative Joined ToLower Enum(gpu_type) Var(gcn_gpu)
> Init(PROCESSOR_CARRIZO)
> +Specify the name of the target GPU.
