> -----Original Message-----
> From: Thomas Schwinge <tschwi...@baylibre.com>
> Sent: Friday, August 9, 2024 12:55 AM
> To: Prathamesh Kulkarni <prathame...@nvidia.com>
> Cc: Andrew Pinski <pins...@gmail.com>; Richard Biener
> <rguent...@suse.de>; gcc-patches@gcc.gnu.org; Jakub Jelinek
> <ja...@redhat.com>
> Subject: Re: [nvptx] Pass -m32/-m64 to host_compiler if it has
> multilib support
>
> External email: Use caution opening links or attachments
>
>
> Hi Prathamesh!
Hi Thomas,
>
> On 2024-08-08T06:46:25-0700, Andrew Pinski <pins...@gmail.com> wrote:
> > On Thu, Aug 8, 2024 at 6:11 AM Prathamesh Kulkarni
> > <prathame...@nvidia.com> wrote:
> >> After differing NUM_POLY_INT_COEFFS fix for AArch64/nvptx
> offloading, the following minimal test:
>
> First, thanks for your work on enabling this! I will say that I had
> the plan to re-engage with Nvidia to hire us (as initial implementors
> of GCC/nvptx offloading) to make AArch64/nvptx offloading work, but
> now that Nvidia has its own GCC team, that's great that you're able to
> work on this yourself! :-)
>
> Please CC me for GCC/nvptx issues for (at least potentially...) faster
> response times.
Thanks, will do 😊
>
> >> compiled with -fopenmp -foffload=nvptx-none now fails with:
> >> gcc: error: unrecognized command-line option '-m64'
> >> nvptx mkoffload: fatal error: ../install/bin/gcc returned 1 exit
> status compilation terminated.
>
> Heh. Yeah...
>
> >> As mentioned in RFC email, this happens because
> >> nvptx/mkoffload.cc:compile_native passes -m64/-m32 to host compiler
> depending on whether offload_abi is OFFLOAD_ABI_LP64 or
> OFFLOAD_ABI_ILP32, and aarch64 backend doesn't recognize these
> options.
> >>
> >> Based on your suggestion in:
> >> https://gcc.gnu.org/pipermail/gcc/2024-July/244470.html,
> >> The attached patch generates new macro HOST_MULTILIB derived from
> >> $enable_as_accelerator_for, and in mkoffload.cc it gates passing
> >> -m32/-m64 to host_compiler on HOST_MULTILIB. I verified that the
> macro is set to 0 for aarch64 host (and thus avoids above unrecognized
> command line option error), and is set to 1 for x86_64 host.
> >>
> >> Does the patch look OK ?
> >
> > Note I think the usage of the name MULTILIB here is wrong because
> > aarch64 (and riscv) could have MUTLILIB support just the options are
> > different.
>
> I also think the proposed patch is not quite the right hammer for the
> issue at hand.
>
> > For aarch64, it would be -mabi=ilp32/-mabi=lp64 (riscv it is more
> > complex).
> >
> > This most likely should be something more complex due to the above.
>
> Right.
>
> > Maybe call it HOST_64_32 but even that seems wrong due to Aarch64
> > having ILP32 support and such.
>
> Right.
>
> > What about HOST_64ABI_OPTS="-mabi=lp64"/HOST_32ABI_OPTS="-
> mabi=ilp32"
> > but I am not sure if that would be enough to support RISCV which
> > requires two options.
>
> So, my idea is: instead of the current strategy that the host
> 'TARGET_OFFLOAD_OPTIONS' synthesizes '-foffload-abi=lp64' etc., which
> the 'mkoffload's then interpret and re-synthesize '-m64' etc. -- how
> about we instead directly tell the 'mkoffload's the relevant ABI
> options? That is, 'TARGET_OFFLOAD_OPTIONS' instead synthesizes '-
> foffload-abi=-m64'
> etc., which the 'mkoffload's can then readily use. Could you please
> give that a try, and/or does anyone see any issues with that approach?
>
> And use something like '-foffload-abi=disable' to replace the current:
>
> /* PR libgomp/65099: Currently, we only support offloading in 64-
> bit
> configurations. */
> if (offload_abi == OFFLOAD_ABI_LP64)
> {
>
> (As discussed before, this should be done differently altogether, but
> that's for another day.)
Sorry, I don't quite follow. Currently we enable offloading if offload_abi ==
OFFLOAD_ABI_LP64,
which is synthesized from -foffload-abi=lp64. If we change -foffload-abi to
instead specify
host-specific ABI opts, I guess mkoffload will still need to somehow figure out
which ABI is used,
so it can disable offloading for 32-bit ? I suppose we could adjust
TARGET_OFFLOAD_OPTIONS for each
host to pass -foffload-abi=disable if TARGET_ILP32 is set and offload target is
nvptx, but not sure
if that'd be correct ?
In the attached patch, I added another option -foffload-abi-host-opts to
specify host abi
opts, and leave -foffload-abi to specify if ABI is 32/64 bit which mkoffload
can use to
enable/disable offloading (as before).
Does that look OK ?
Signed-off-by: Prathamesh Kulkarni <prathame...@nvidia.com>
Thanks,
Prathamesh
>
>
> Grüße
> Thomas
[nvptx] Pass host specific ABI opts from mkoffload.
The patch adds an option -foffload-abi-host-opts, which
is set by host in TARGET_OFFLOAD_OPTIONS, and mkoffload then passes it's value
to host_compiler.
gcc/ChangeLog:
* common.opt (foffload-abi-host-opts): New option.
* config/aarch64/aarch64.cc (aarch64_offload_options): Set
-foffload-abi-host-opts.
* config/i386/i386-opts.cc (ix86_offload_options): Likewise.
* config/rs6000/rs6000.cc (rs6000_offload_options): Likewise.
* config/nvptx/mkoffload.cc (host_abi_opts): Define.
(compile_native): Append host_abi_opts to argv_obstack.
(main): Handle option -foffload-abi-host-opts.
* lto-wrapper.cc (append_compiler_options): Handle
-foffload-abi-host-opts.
* opts.cc (common_handle_option): Likewise.
Signed-off-by: Prathamesh Kulkarni <prathame...@nvidia.com>
diff --git a/gcc/common.opt b/gcc/common.opt
index ea39f87ae71..d1a9efb9513 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2361,6 +2361,10 @@ Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
EnumValue
Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
+foffload-abi-host-opts=
+Common Driver Joined MissingArgError(option or option=abi missing after %qs)
+-foffload-abi-host-opts=<options>=<abi> Specify host abi options.
+
fomit-frame-pointer
Common Var(flag_omit_frame_pointer) Optimization
When possible do not generate stack frames.
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 2ac5a22c848..7418cb1fb69 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -18999,9 +18999,9 @@ static char *
aarch64_offload_options (void)
{
if (TARGET_ILP32)
- return xstrdup ("-foffload-abi=ilp32");
+ return xstrdup ("-foffload-abi=ilp32 -foffload-abi-host-opts=-mabi=ilp32");
else
- return xstrdup ("-foffload-abi=lp64");
+ return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-mabi=lp64");
}
static struct machine_function *
diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 1c8f7835af2..bd960674e5d 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3669,8 +3669,8 @@ char *
ix86_offload_options (void)
{
if (TARGET_LP64)
- return xstrdup ("-foffload-abi=lp64");
- return xstrdup ("-foffload-abi=ilp32");
+ return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-m64");
+ return xstrdup ("-foffload-abi=ilp32 -foffload-abi-host-opts=-m32");
}
/* Handle "cdecl", "stdcall", "fastcall", "regparm", "thiscall",
diff --git a/gcc/config/nvptx/mkoffload.cc b/gcc/config/nvptx/mkoffload.cc
index 503b1abcefd..d5ca2386641 100644
--- a/gcc/config/nvptx/mkoffload.cc
+++ b/gcc/config/nvptx/mkoffload.cc
@@ -61,6 +61,7 @@ static const char *omp_requires_file;
static const char *ptx_dumpbase;
enum offload_abi offload_abi = OFFLOAD_ABI_UNSET;
+const char *host_abi_opts = NULL;
/* Delete tempfiles. */
@@ -607,17 +608,9 @@ compile_native (const char *infile, const char *outfile,
const char *compiler,
obstack_ptr_grow (&argv_obstack, ptx_dumpbase);
obstack_ptr_grow (&argv_obstack, "-dumpbase-ext");
obstack_ptr_grow (&argv_obstack, ".c");
- switch (offload_abi)
- {
- case OFFLOAD_ABI_LP64:
- obstack_ptr_grow (&argv_obstack, "-m64");
- break;
- case OFFLOAD_ABI_ILP32:
- obstack_ptr_grow (&argv_obstack, "-m32");
- break;
- default:
- gcc_unreachable ();
- }
+ if (!host_abi_opts)
+ fatal_error (input_location, "-foffload-abi-host-opts not specified.");
+ obstack_ptr_grow (&argv_obstack, host_abi_opts);
obstack_ptr_grow (&argv_obstack, infile);
obstack_ptr_grow (&argv_obstack, "-c");
obstack_ptr_grow (&argv_obstack, "-o");
@@ -721,6 +714,8 @@ main (int argc, char **argv)
"unrecognizable argument of option " STR);
}
#undef STR
+ else if (startswith (argv[i], "-foffload-abi-host-opts="))
+ host_abi_opts = argv[i] + strlen ("-foffload-abi-host-opts=");
else if (strcmp (argv[i], "-fopenmp") == 0)
fopenmp = true;
else if (strcmp (argv[i], "-fopenacc") == 0)
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 0bcc6a2d0ab..decdf49a1f5 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -17333,9 +17333,9 @@ static char *
rs6000_offload_options (void)
{
if (TARGET_64BIT)
- return xstrdup ("-foffload-abi=lp64");
+ return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-m64");
else
- return xstrdup ("-foffload-abi=ilp32");
+ return xstrdup ("-foffload-abi=ilp32 -foffload-abi-host-opts=-m32");
}
diff --git a/gcc/lto-wrapper.cc b/gcc/lto-wrapper.cc
index 6bfc96590a5..1ecc4997e5a 100644
--- a/gcc/lto-wrapper.cc
+++ b/gcc/lto-wrapper.cc
@@ -745,6 +745,7 @@ append_compiler_options (obstack *argv_obstack,
vec<cl_decoded_option> opts)
case OPT_fopenacc:
case OPT_fopenacc_dim_:
case OPT_foffload_abi_:
+ case OPT_foffload_abi_host_opts_:
case OPT_fcf_protection_:
case OPT_fasynchronous_unwind_tables:
case OPT_funwind_tables:
diff --git a/gcc/opts.cc b/gcc/opts.cc
index 0b7b137c376..79118237ce4 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -3069,6 +3069,7 @@ common_handle_option (struct gcc_options *opts,
break;
case OPT_foffload_abi_:
+ case OPT_foffload_abi_host_opts_:
#ifdef ACCEL_COMPILER
/* Handled in the 'mkoffload's. */
#else
