Re: Fix Intel MIC 'mkoffload' for OpenMP 'requires' (was: [Patch] OpenMP: Move omp requires checks to libgomp)

[Tobias Burnus <tobias@codesourcery.com>]

Hi Thomas, hello all,

On 06.07.22 13:04, Thomas Schwinge wrote:
> On 2022-06-08T05:56:02+0200, Tobias Burnus <Tobias_Burnus@mentor.com>
> wrote:
>> PS: I have not fully tested the intelmic version.
...
> Subject: [PATCH] Fix Intel MIC 'mkoffload' for OpenMP 'requires'
...
> This also means finally switching Intel MIC 'mkoffload' to
> 'GOMP_offload_register_ver', 'GOMP_offload_unregister_ver',
> making 'GOMP_offload_register', 'GOMP_offload_unregister'
> legacy entry points.
...
>       gcc/
>       * config/i386/intelmic-mkoffload.cc (generate_host_descr_file)
>       (prepare_target_image, main): Handle OpenMP 'requires'.
>       (generate_host_descr_file): Switch to 'GOMP_offload_register_ver',
>       'GOMP_offload_unregister_ver'.
>       libgomp/
>       * target.c (GOMP_offload_register, GOMP_offload_unregister):
>       Denote as legacy entry points.
>       * testsuite/libgomp.c-c++-common/requires-1.c: Enable for all
>       'target offloading_enabled'.
>       * testsuite/libgomp.c-c++-common/requires-5.c: Likewise.
>       * testsuite/libgomp.c-c++-common/requires-7.c: Likewise.
>       * testsuite/libgomp.fortran/requires-1.f90: Likewise.
...
> diff --git a/gcc/config/i386/intelmic-mkoffload.cc b/gcc/config/i386/intelmic-mkoffload.cc
> index c683d6f473e..596f6f107b8 100644
> --- a/gcc/config/i386/intelmic-mkoffload.cc
> +++ b/gcc/config/i386/intelmic-mkoffload.cc
> @@ -370,7 +370,7 @@ generate_target_offloadend_file (const char *target_compiler)
>
>   /* Generates object file with the host side descriptor.  */
>   static const char *
> -generate_host_descr_file (const char *host_compiler)
> +generate_host_descr_file (const char *host_compiler, uint32_t omp_requires)
>   {
>     char *dump_filename = concat (dumppfx, "_host_descr.c", NULL);
>     const char *src_filename = save_temps
> @@ -386,39 +386,50 @@ generate_host_descr_file (const char *host_compiler)
>     if (!src_file)
>       fatal_error (input_location, "cannot open '%s'", src_filename);
>
> +  fprintf (src_file, "#include <stdint.h>\n\n");
> +
>     fprintf (src_file,
>          "extern const void *const __OFFLOAD_TABLE__;\n"
>          "extern const void *const __offload_image_intelmic_start;\n"
>          "extern const void *const __offload_image_intelmic_end;\n\n"
>
> -        "static const void *const __offload_target_data[] = {\n"
> +        "static const struct intelmic_data {\n"
> +        "  uintptr_t omp_requires_mask;\n"
> +        "  const void *const image_start;\n"
> +        "  const void *const image_end;\n"
> +        "} intelmic_data = {\n"
> +        "  %d,\n"
>          "  &__offload_image_intelmic_start, &__offload_image_intelmic_end\n"
> -        "};\n\n");
> +        "};\n\n", omp_requires);
>
>     fprintf (src_file,
>          "#ifdef __cplusplus\n"
>          "extern \"C\"\n"
>          "#endif\n"
> -        "void GOMP_offload_register (const void *, int, const void *);\n"
> +        "void GOMP_offload_register_ver (unsigned, const void *, int, const void *);\n"
This line now ends in column 90, I think you want to wrap it.
>          "#ifdef __cplusplus\n"
>          "extern \"C\"\n"
>          "#endif\n"
> -        "void GOMP_offload_unregister (const void *, int, const void *);\n\n"
> +        "void GOMP_offload_unregister_ver (unsigned, const void *, int, const void *);\n\n"
Likewise - before col 80, now col 94.
>
>          "__attribute__((constructor))\n"
>          "static void\n"
>          "init (void)\n"
>          "{\n"
> -        "  GOMP_offload_register (&__OFFLOAD_TABLE__, %d, __offload_target_data);\n"
> -        "}\n\n", GOMP_DEVICE_INTEL_MIC);
> +        "  GOMP_offload_register_ver (%#x, &__OFFLOAD_TABLE__, %d, &intelmic_data);\n"
Likewise - albeit before already col 87, now col 89.
> +        "}\n\n",
> +        GOMP_VERSION_PACK (GOMP_VERSION, GOMP_VERSION_INTEL_MIC),
> +        GOMP_DEVICE_INTEL_MIC);
>
>     fprintf (src_file,
>          "__attribute__((destructor))\n"
>          "static void\n"
>          "fini (void)\n"
>          "{\n"
> -        "  GOMP_offload_unregister (&__OFFLOAD_TABLE__, %d, __offload_target_data);\n"
> -        "}\n", GOMP_DEVICE_INTEL_MIC);
>
> +        "}\n",
> +        GOMP_VERSION_PACK (GOMP_VERSION, GOMP_VERSION_INTEL_MIC),
> +        GOMP_DEVICE_INTEL_MIC);
>
>     fclose (src_file);
>
> @@ -462,7 +473,7 @@ generate_host_descr_file (const char *host_compiler)
>   }
>
>   static const char *
> -prepare_target_image (const char *target_compiler, int argc, char **argv)
> +prepare_target_image (const char *target_compiler, int argc, char **argv, uint32_t *omp_requires)
Likewise now too long.
>   {
>     const char *target_descr_filename
>       = generate_target_descr_file (target_compiler);
> @@ -509,8 +520,26 @@ prepare_target_image (const char *target_compiler, int argc, char **argv)
>     obstack_ptr_grow (&argv_obstack, "");
>     obstack_ptr_grow (&argv_obstack, "-o");
>     obstack_ptr_grow (&argv_obstack, target_so_filename);
> +
> +  char *omp_requires_file;
> +  if (save_temps)
> +    omp_requires_file = concat (dumppfx, ".mkoffload.omp_requires", NULL);
> +  else
> +    omp_requires_file = make_temp_file (".mkoffload.omp_requires");
> +  xputenv (concat ("GCC_OFFLOAD_OMP_REQUIRES_FILE=", omp_requires_file, NULL));
> +
>     compile_for_target (&argv_obstack);
>
> +  unsetenv("GCC_OFFLOAD_OMP_REQUIRES_FILE");
> +  FILE *in = fopen (omp_requires_file, "rb");
> +  if (!in)
> +    fatal_error (input_location, "cannot open omp_requires file %qs",
> +              omp_requires_file);
> +  if (fread (omp_requires, sizeof (*omp_requires), 1, in) != 1)
> +    fatal_error (input_location, "cannot read omp_requires file %qs",
> +              omp_requires_file);
> +  fclose (in);
> +
>     /* Run objcopy.  */
>     char *rename_section_opt
>       = XALLOCAVEC (char, sizeof (".data=") + strlen (image_section_name));
> @@ -643,10 +672,13 @@ main (int argc, char **argv)
>     if (!dumppfx)
>       dumppfx = out_obj_filename;
>
> +  uint32_t omp_requires;
> +
>     const char *target_so_filename
> -    = prepare_target_image (target_compiler, argc, argv);
> +    = prepare_target_image (target_compiler, argc, argv, &omp_requires);
>
> -  const char *host_descr_filename = generate_host_descr_file (host_compiler);
> +  const char *host_descr_filename
> +    = generate_host_descr_file (host_compiler, omp_requires);
>
>     /* Perform partial linking for the target image and host side descriptor.
>        As a result we'll get a finalized object file with all offload data.  */
> diff --git a/libgomp/target.c b/libgomp/target.c
> index 288b748b9e8..18c5f6e27db 100644
> --- a/libgomp/target.c
> +++ b/libgomp/target.c
> @@ -2410,6 +2410,8 @@ GOMP_offload_register_ver (unsigned version, const void *host_table,
>     gomp_mutex_unlock (&register_lock);
>   }
>
> +/* Legacy entry point.  */
> +
>   void
>   GOMP_offload_register (const void *host_table, int target_type,
>                      const void *target_data)
> @@ -2465,6 +2467,8 @@ GOMP_offload_unregister_ver (unsigned version, const void *host_table,
>     gomp_mutex_unlock (&register_lock);
>   }
>
> +/* Legacy entry point.  */
> +
>   void
>   GOMP_offload_unregister (const void *host_table, int target_type,
>                        const void *target_data)

Except for the too-long lines, it LGTM up to here.

However, regarding the following, I prefer to have something like 'offload_target_any'
(or similar), instead of (ab)using 'offloading_enabled', as discussed elsewhere in this thread.

While it does not make currently any difference, I could imagine to do the same
for OpenMP as done in libgomp.oacc-*/*exp. Namely: Compile/run all 'omp target'
testcases in addition with -foffload=disable.

As we don't do this, yet, I think it is fine to apply the patch for now. However, if
you don't want to fix it as follow up (please do), can you at least open a PR about it?

> diff --git a/libgomp/testsuite/libgomp.c-c++-common/requires-1.c b/libgomp/testsuite/libgomp.c-c++-common/requires-1.c
> index fedf9779769..8eaac54e187 100644
> --- a/libgomp/testsuite/libgomp.c-c++-common/requires-1.c
> +++ b/libgomp/testsuite/libgomp.c-c++-common/requires-1.c
> @@ -1,4 +1,4 @@
> -/* { dg-do link { target { offload_target_nvptx || offload_target_amdgcn } } } */
> +/* { dg-do link { target offloading_enabled } } */
>   /* { dg-additional-sources requires-1-aux.c } */
>
>   /* Check diagnostic by device-compiler's lto1.
> diff --git a/libgomp/testsuite/libgomp.c-c++-common/requires-5.c b/libgomp/testsuite/libgomp.c-c++-common/requires-5.c
> index c1e5540cfc5..5aa04a5a604 100644
> --- a/libgomp/testsuite/libgomp.c-c++-common/requires-5.c
> +++ b/libgomp/testsuite/libgomp.c-c++-common/requires-5.c
> @@ -1,4 +1,4 @@
> -/* { dg-do run { target { offload_target_nvptx || offload_target_amdgcn } } } */
> +/* { dg-do run { target offloading_enabled } } */
>   /* { dg-additional-sources requires-5-aux.c } */
>
>   #pragma omp requires unified_shared_memory, unified_address, reverse_offload
> diff --git a/libgomp/testsuite/libgomp.c-c++-common/requires-7.c b/libgomp/testsuite/libgomp.c-c++-common/requires-7.c
> index c94a4c10846..31c6f73c6da 100644
> --- a/libgomp/testsuite/libgomp.c-c++-common/requires-7.c
> +++ b/libgomp/testsuite/libgomp.c-c++-common/requires-7.c
> @@ -1,4 +1,4 @@
> -/* { dg-do link { target { offload_target_nvptx || offload_target_amdgcn } } } */
> +/* { dg-do link { target offloading_enabled } } */
>   /* { dg-additional-sources requires-7-aux.c } */
>
>   /* Check diagnostic by device-compiler's lto1.
> diff --git a/libgomp/testsuite/libgomp.fortran/requires-1.f90 b/libgomp/testsuite/libgomp.fortran/requires-1.f90
> index 33741af15f1..1020ebb4277 100644
> --- a/libgomp/testsuite/libgomp.fortran/requires-1.f90
> +++ b/libgomp/testsuite/libgomp.fortran/requires-1.f90
> @@ -1,4 +1,4 @@
> -! { dg-do link { target { offload_target_nvptx || offload_target_amdgcn } } }
> +! { dg-do link { target offloading_enabled } }
>   ! { dg-additional-sources requires-1-aux.f90 }
>
>   ! Check diagnostic by device-compiler's lto1.

Thanks,

Tobias

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