nvptx, libgfortran: Switch out of "minimal" mode
Commit Message
Hi!
On 2023-01-20T22:04:02+0100, I wrote:
> We've been (t)asked to enable (portions of) GCC/Fortran I/O for nvptx
> offloading, which means building a normal (non-'LIBGFOR_MINIMAL')
> configuration of libgfortran.
This is achieved by 'nvptx, libgfortran: Switch out of "minimal" mode',
see attached, again based on WIP work by Andrew Stubbs. This I've just
pushed to devel/omp/gcc-12 branch in
commit c7734c6fbb5513b4da6306de7bc85de9b8547988, and would like to push
to master branch once other pending GCC patches have been accepted.
The OpenACC XFAILs: "[...] overflows the stack for nvptx offloading"
are unresolved at this point; see the discussion around
"Handling of large stack objects in GPU code generation -- maybe transform into heap allocation?",
and my "nvptx: '-mframe-malloc-threshold', '-Wframe-malloc-threshold'"
experimenting. (The latter works to some extent, but also has other
issues that I shall detail at some later point in time.)
Grüße
Thomas
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
Comments
Hi Thomas,
> On 2023-01-20T22:04:02+0100, I wrote:
>> We've been (t)asked to enable (portions of) GCC/Fortran I/O for nvptx
>> offloading, which means building a normal (non-'LIBGFOR_MINIMAL')
>> configuration of libgfortran.
>
> This is achieved by 'nvptx, libgfortran: Switch out of "minimal" mode',
> see attached, again based on WIP work by Andrew Stubbs. This I've just
> pushed to devel/omp/gcc-12 branch in
> commit c7734c6fbb5513b4da6306de7bc85de9b8547988, and would like to push
> to master branch once other pending GCC patches have been accepted.
Looks good to me.
Regards
Thomas
From c7734c6fbb5513b4da6306de7bc85de9b8547988 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Wed, 21 Sep 2022 18:58:34 +0200
Subject: [PATCH] nvptx, libgfortran: Switch out of "minimal" mode
..., in order to enable (portions of) Fortran I/O, for example.
libgfortran/ChangeLog:
* configure: Regenerate.
* configure.ac: No longer set LIBGFOR_MINIMAL for nvptx.
libgomp/ChangeLog:
* testsuite/libgomp.fortran/target-print-1.f90: Adjust.
* testsuite/libgomp.fortran/target-print-1-nvptx.f90: Remove.
* testsuite/libgomp.oacc-fortran/print-1.f90: Adjust.
* testsuite/libgomp.oacc-fortran/print-1-nvptx.f90: Remove.
* testsuite/libgomp.oacc-fortran/error_stop-2.f: Adjust.
* testsuite/libgomp.oacc-fortran/stop-2.f: Likewise.
Co-authored-by: Andrew Stubbs <ams@codesourcery.com>
---
libgfortran/ChangeLog.omp | 6 ++++++
libgfortran/configure | 17 ++++++-----------
libgfortran/configure.ac | 17 ++++++-----------
libgomp/ChangeLog.omp | 7 +++++++
.../libgomp.fortran/target-print-1-nvptx.f90 | 11 -----------
.../libgomp.fortran/target-print-1.f90 | 3 ---
.../libgomp.oacc-fortran/error_stop-2.f | 4 +++-
.../libgomp.oacc-fortran/print-1-nvptx.f90 | 11 -----------
.../testsuite/libgomp.oacc-fortran/print-1.f90 | 5 ++---
libgomp/testsuite/libgomp.oacc-fortran/stop-2.f | 4 +++-
10 files changed, 33 insertions(+), 52 deletions(-)
delete mode 100644 libgomp/testsuite/libgomp.fortran/target-print-1-nvptx.f90
delete mode 100644 libgomp/testsuite/libgomp.oacc-fortran/print-1-nvptx.f90
@@ -1,3 +1,9 @@
+2023-01-20 Thomas Schwinge <thomas@codesourcery.com>
+ Andrew Stubbs <ams@codesourcery.com>
+
+ * configure: Regenerate.
+ * configure.ac: No longer set LIBGFOR_MINIMAL for nvptx.
+
2023-01-20 Thomas Schwinge <thomas@codesourcery.com>
PR target/85463
@@ -6230,17 +6230,12 @@ else
fi
-# For GPU offloading, not everything in libfortran can be supported.
-# Currently, the only target that has this problem is nvptx. The
-# following is a (partial) list of features that are unsupportable on
-# this particular target:
-# * Constructors
-# * alloca
-# * C library support for I/O, with printf as the one notable exception
-# * C library support for other features such as signal, environment
-# variables, time functions
-
- if test "x${target_cpu}" = xnvptx; then
+# "Minimal" mode is for targets that cannot (yet) support all features of
+# libgfortran. It avoids the need for working constructors, alloca, and C
+# library support for I/O, signals, environment variables, time functions, etc.
+# At present there are no targets that require this mode.
+
+ if false; then
LIBGFOR_MINIMAL_TRUE=
LIBGFOR_MINIMAL_FALSE='#'
else
@@ -222,17 +222,12 @@ AM_CONDITIONAL(LIBGFOR_USE_SYMVER, [test "x$gfortran_use_symver" != xno])
AM_CONDITIONAL(LIBGFOR_USE_SYMVER_GNU, [test "x$gfortran_use_symver" = xgnu])
AM_CONDITIONAL(LIBGFOR_USE_SYMVER_SUN, [test "x$gfortran_use_symver" = xsun])
-# For GPU offloading, not everything in libfortran can be supported.
-# Currently, the only target that has this problem is nvptx. The
-# following is a (partial) list of features that are unsupportable on
-# this particular target:
-# * Constructors
-# * alloca
-# * C library support for I/O, with printf as the one notable exception
-# * C library support for other features such as signal, environment
-# variables, time functions
-
-AM_CONDITIONAL(LIBGFOR_MINIMAL, [test "x${target_cpu}" = xnvptx])
+# "Minimal" mode is for targets that cannot (yet) support all features of
+# libgfortran. It avoids the need for working constructors, alloca, and C
+# library support for I/O, signals, environment variables, time functions, etc.
+# At present there are no targets that require this mode.
+
+AM_CONDITIONAL(LIBGFOR_MINIMAL, false)
# Some compiler target support may have limited support for integer
# or floating point numbers – or may want to reduce the libgfortran size
@@ -1,5 +1,12 @@
2023-01-20 Thomas Schwinge <thomas@codesourcery.com>
+ * testsuite/libgomp.fortran/target-print-1.f90: Adjust.
+ * testsuite/libgomp.fortran/target-print-1-nvptx.f90: Remove.
+ * testsuite/libgomp.oacc-fortran/print-1.f90: Adjust.
+ * testsuite/libgomp.oacc-fortran/print-1-nvptx.f90: Remove.
+ * testsuite/libgomp.oacc-fortran/error_stop-2.f: Adjust.
+ * testsuite/libgomp.oacc-fortran/stop-2.f: Likewise.
+
* plugin/plugin-nvptx.c (nvptx_do_global_cdtors): New.
(nvptx_close_device, GOMP_OFFLOAD_load_image)
(GOMP_OFFLOAD_unload_image): Call it.
deleted file mode 100644
@@ -1,11 +0,0 @@
-! Ensure that write on the offload device works, nvptx offloading variant.
-
-! This doesn't compile: for nvptx offloading we're using a minimal libgfortran
-! configuration.
-! { dg-do link } ! ..., but still apply 'dg-do run' options.
-! { dg-xfail-if "minimal libgfortran" { offload_target_nvptx } }
-
-! Skip duplicated testing.
-! { dg-skip-if "separate file" { ! offload_target_nvptx } }
-
-include 'target-print-1.f90'
@@ -3,9 +3,6 @@
! { dg-do run }
! { dg-output "The answer is 42(\n|\r\n|\r)+" }
-! Separate file 'target-print-1-nvptx.f90' for nvptx offloading.
-! { dg-skip-if "separate file" { offload_target_nvptx } }
-
program main
implicit none
integer :: var = 42
@@ -17,7 +17,9 @@
! { dg-output "CheCKpOInT(\n|\r\n|\r)+" }
-! { dg-output "ERROR STOP 35(\n|\r\n|\r)+" }
+! '_gfortran_error_stop_numeric' -> '_gfortrani_st_printf' -> [...]
+! overflows the stack for nvptx offloading, thus XFAILed.
+! { dg-output "ERROR STOP 35(\n|\r\n|\r)+" { xfail openacc_nvidia_accel_selected } }
!
! In gfortran's main program, libfortran's set_options is called - which sets
! compiler_options.backtrace = 1 by default. For an offload libgfortran, this
deleted file mode 100644
@@ -1,11 +0,0 @@
-! Ensure that write on the offload device works, nvptx offloading variant.
-
-! This doesn't compile: for nvptx offloading we're using a minimal libgfortran
-! configuration.
-! { dg-do link } ! ..., but still apply 'dg-do run' options.
-! { dg-xfail-if "minimal libgfortran" { offload_target_nvptx } }
-
-! Skip duplicated testing.
-! { dg-skip-if "separate file" { ! offload_target_nvptx } }
-
-include 'print-1.f90'
@@ -2,9 +2,8 @@
! { dg-do run }
! { dg-output "The answer is 42(\n|\r\n|\r)+" }
-
-! Separate file 'print-1-nvptx.f90' for nvptx offloading.
-! { dg-skip-if "separate file" { offload_target_nvptx } }
+! The 'write' overflows the stack for nvptx offloading, thus XFAILed.
+! { dg-xfail-run-if TODO { openacc_nvidia_accel_selected } }
! { dg-additional-options "-fopt-info-note-omp" }
! { dg-additional-options "-foffload=-fopt-info-note-omp" }
@@ -17,7 +17,9 @@
! { dg-output "CheCKpOInT(\n|\r\n|\r)+" }
-! { dg-output "STOP 35(\n|\r\n|\r)+" }
+! '_gfortran_error_stop_numeric' -> '_gfortrani_st_printf' -> [...]
+! overflows the stack for nvptx offloading, thus XFAILed.
+! { dg-output "STOP 35(\n|\r\n|\r)+" { xfail openacc_nvidia_accel_selected } }
!
! PR85463. The 'exit' implementation used with nvptx
! offloading is a little bit different.
--
2.25.1