Re: [PATCH] [gfortran] Add support for allocate clause (OpenMP 5.0).

[Tobias Burnus <tobias@codesourcery.com>]

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On 21.01.22 18:43, Tobias Burnus wrote:
> On 21.01.22 18:15, Thomas Schwinge wrote:
>>         11 |     integer(c_int) function is_64bit_aligned (a) bind(C)
>>      Warning: Variable ‘a’ at (1) is a dummy argument of the BIND(C)
>> procedure ‘is_64bit_aligned’ but may not be C interoperable
>> [-Wc-binding-type]
>>
>> Is that something to worry about?
I have attached a patch (not commited), which silences the three kind of
warnings and fixes the interface issue.
TODO: commit it.

On 21.01.22 18:15, Thomas Schwinge wrote:
> I'm seeing this test case randomly/non-deterministically FAIL to execute,
> differently on different systems and runs, for example: [...]
> I'd assume there's some concurrency issue: the problem disappears if I
> manually specify a lowerish 'OMP_NUM_THREADS'

If one compiles the program with -fsanitize=thread, it shows tons of errors :-(
The first one is:

WARNING: ThreadSanitizer: data race (pid=3034413)
   Read of size 8 at 0x7fff8b5a8340 by thread T1:
     #0 __m_MOD_foo._omp_fn.2 ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 (a.out+0x402a88)
     #1 gomp_thread_start ../../../repos/gcc-trunk-commit/libgomp/team.c:129 (libgomp.so.1+0x1e5ed)

   Previous write of size 8 at 0x7fff8b5a8340 by main thread:
     #0 __m_MOD_foo._omp_fn.1 ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 (a.out+0x4029c0)
     #1 GOMP_teams_reg ../../../repos/gcc-trunk-commit/libgomp/teams.c:51 (libgomp.so.1+0x3638c)
     #2 MAIN__ ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:328 (a.out+0x4024c0)
     #3 main ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:312 (a.out+0x4025b0)

   Location is stack of main thread.

   Location is global '<null>' at 0x000000000000 ([stack]+0x1f340)

   Thread T1 (tid=3034416, running) created by main thread at:
     #0 pthread_create ../../../../repos/gcc-trunk-commit/libsanitizer/tsan/tsan_interceptors_posix.cpp:1001 (libtsan.so.2+0x62c76)
     #1 gomp_team_start ../../../repos/gcc-trunk-commit/libgomp/team.c:858 (libgomp.so.1+0x1ec18)
     #2 MAIN__ ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:328 (a.out+0x4024c0)
     #3 main ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:312 (a.out+0x4025b0)

SUMMARY: ThreadSanitizer: data race ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 in __m_MOD_foo._omp_fn.2

Tobias
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diff --git a/libgomp/testsuite/libgomp.fortran/allocate-1.c b/libgomp/testsuite/libgomp.fortran/allocate-1.c
index d33acc6feef..cb6d355afc6 100644
--- a/libgomp/testsuite/libgomp.fortran/allocate-1.c
+++ b/libgomp/testsuite/libgomp.fortran/allocate-1.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 
 int
-is_64bit_aligned_ (uintptr_t a)
+is_64bit_aligned (uintptr_t a)
 {
   return ( (a & 0x3f) == 0);
 }
diff --git a/libgomp/testsuite/libgomp.fortran/allocate-1.f90 b/libgomp/testsuite/libgomp.fortran/allocate-1.f90
index 35d1750b878..f31bd533e7f 100644
--- a/libgomp/testsuite/libgomp.fortran/allocate-1.f90
+++ b/libgomp/testsuite/libgomp.fortran/allocate-1.f90
@@ -5,30 +5,30 @@
 module m
   use omp_lib
   use iso_c_binding
-  implicit none
+  implicit none (type, external)
 
   interface
     integer(c_int) function is_64bit_aligned (a) bind(C)
       import :: c_int
-      integer  :: a
+      type(*)  :: a
     end
   end interface
-end module m
 
-subroutine foo (x, p, q, px, h, fl)
+contains
+
+subroutine foo (x, p, q, h, fl)
   use omp_lib
   use iso_c_binding
   integer  :: x
   integer, dimension(4) :: p
   integer, dimension(4) :: q
-  integer  :: px
   integer (kind=omp_allocator_handle_kind) :: h
   integer  :: fl
 
   integer  :: y
   integer  :: r, i, i1, i2, i3, i4, i5
   integer  :: l, l3, l4, l5, l6
-  integer  :: n, n1, n2, n3, n4
+  integer  :: n, n2, n3, n4
   integer  :: j2, j3, j4
   integer, dimension(4) :: l2
   integer, dimension(4) :: r2
@@ -118,6 +118,7 @@ subroutine foo (x, p, q, px, h, fl)
   end if
   !$omp end parallel
   !$omp end teams
+stop
 
   !$omp parallel do private (y) firstprivate (x)  reduction(+: r) allocate (h: x, y, r, l, n) lastprivate (l)  linear (n: 16)
   do i = 0, 63
@@ -153,77 +154,77 @@ subroutine foo (x, p, q, px, h, fl)
            ((is_64bit_aligned(l2(1)) == 0) .or. &
             (is_64bit_aligned(l3) == 0) .or. &
             (is_64bit_aligned(i1) == 0))) then
-	stop 10
+        stop 10
       end if
     end do
 
     !$omp do collapse(2) lastprivate(l4, i2, j2) linear (n2:17) allocate (h: n2, l4, i2, j2)
     do i2 = 3, 4
       do j2 = 17, 22, 2
-	n2 = n2 + 17
-	l4 = i2 * 31 + j2
-	if ( (and(fl, 1) /= 0) .and.          &
-	  ((is_64bit_aligned(l4) == 0) .or. &
-	  (is_64bit_aligned(n2) == 0) .or. &
-	  (is_64bit_aligned(i2) == 0) .or. &
-	  (is_64bit_aligned(j2) == 0))) then
-	  stop 11
-	end if
+        n2 = n2 + 17
+        l4 = i2 * 31 + j2
+        if ( (and(fl, 1) /= 0) .and.          &
+             ((is_64bit_aligned(l4) == 0) .or. &
+              (is_64bit_aligned(n2) == 0) .or. &
+              (is_64bit_aligned(i2) == 0) .or. &
+              (is_64bit_aligned(j2) == 0))) then
+          stop 11
+        end if
       end do
     end do
 
     !$omp do collapse(2) lastprivate(l5, i3, j3) linear (n3:17) schedule (static, 3) allocate (n3, l5, i3, j3)
     do i3 = 3, 4
       do j3 = 17, 22, 2
-	  n3 = n3 + 17
-	  l5 = i3 * 31 + j3
-	  if ( (and(fl, 2) /= 0) .and.      &
-	  ((is_64bit_aligned(l5) == 0) .or. &
-	  (is_64bit_aligned(n3) == 0) .or. &
-	  (is_64bit_aligned(i3) == 0) .or. &
-	  (is_64bit_aligned(j3) == 0))) then
-	  stop 12
-	end if
+          n3 = n3 + 17
+          l5 = i3 * 31 + j3
+          if ( (and(fl, 2) /= 0) .and.      &
+             ((is_64bit_aligned(l5) == 0) .or. &
+              (is_64bit_aligned(n3) == 0) .or. &
+              (is_64bit_aligned(i3) == 0) .or. &
+              (is_64bit_aligned(j3) == 0))) then
+          stop 12
+        end if
       end do
     end do
 
     !$omp do collapse(2) lastprivate(l6, i4, j4) linear (n4:17) schedule (dynamic) allocate (h: n4, l6, i4, j4)
     do i4 = 3, 4
       do j4 = 17, 22,2
-	  n4 = n4 + 17;
-	  l6 = i4 * 31 + j4;
-	if ( (and(fl, 1) /= 0) .and.          &
-	  ((is_64bit_aligned(l6) == 0) .or. &
-	  (is_64bit_aligned(n4) == 0) .or. &
-	  (is_64bit_aligned(i4) == 0) .or. &
-	  (is_64bit_aligned(j4) == 0))) then
-	  stop 13
-	end if
+          n4 = n4 + 17;
+          l6 = i4 * 31 + j4;
+        if ( (and(fl, 1) /= 0) .and.          &
+            ((is_64bit_aligned(l6) == 0) .or. &
+             (is_64bit_aligned(n4) == 0) .or. &
+             (is_64bit_aligned(i4) == 0) .or. &
+             (is_64bit_aligned(j4) == 0))) then
+          stop 13
+        end if
       end do
     end do
 
     !$omp do lastprivate (i5) allocate (i5)
     do i5 = 1, 17, 3
       if ( (and(fl, 2) /= 0) .and.          &
-	   (is_64bit_aligned(i5) == 0)) then
-	stop 14
+           (is_64bit_aligned(i5) == 0)) then
+        stop 14
       end if
     end do
 
     !$omp do reduction(+:p, q, r2) allocate(h: p, q, r2)
     do i = 0, 31
-	p(3) = p(3) +  i;
-	p(4) = p(4) + (2 * i)
-	q(1) = q(1) + (3 * i)
-	q(3) = q(3) + (4 * i)
-	r2(1) = r2(1) + (5 * i)
-	r2(4) = r2(4) + (6 * i)
-	if ( (and(fl, 1) /= 0) .and.          &
-	  ((is_64bit_aligned(q(1)) == 0) .or. &
-	  (is_64bit_aligned(p(1)) == 0) .or. &
-	  (is_64bit_aligned(r2(1)) == 0) )) then
-	  stop 15
-	end if
+        p(3) = p(3) +  i;
+        p(4) = p(4) + (2 * i)
+        q(1) = q(1) + (3 * i)
+        q(3) = q(3) + (4 * i)
+        r2(1) = r2(1) + (5 * i)
+        r2(4) = r2(4) + (6 * i)
+        if ( (and(fl, 1) /= 0) .and.             &
+             ((is_64bit_aligned(q(1)) == 0) .or. &
+              (is_64bit_aligned(p(1)) == 0) .or. &
+              (is_64bit_aligned(r2(1)) == 0) )) then
+          stop 15
+        end if
     end do
 
     !$omp task private(y) firstprivate(x) allocate(x, y)
@@ -305,11 +306,13 @@ subroutine foo (x, p, q, px, h, fl)
       .or. r2(1) /= (5 * p(3)) .or. r2(4) /= (6 * p(3))) then
     stop 25
   end if
-
 end subroutine
+end module m
 
 program main
   use omp_lib
+  use m
+  implicit none (type, external)
   integer, dimension(4) :: p
   integer, dimension(4) :: q
 
@@ -323,11 +326,11 @@ program main
   if (a == omp_null_allocator) stop 1
 
   call omp_set_default_allocator (omp_default_mem_alloc);
-  call foo (42, p, q, 2, a, 0);
-  call foo (42, p, q, 2, omp_default_mem_alloc, 0);
-  call foo (42, p, q, 2, a, 1);
+  call foo (42, p, q, a, 0);
+  call foo (42, p, q, omp_default_mem_alloc, 0);
+  call foo (42, p, q, a, 1);
   call omp_set_default_allocator (a);
-  call foo (42, p, q, 2, omp_null_allocator, 3);
-  call foo (42, p, q, 2, omp_default_mem_alloc, 2);
+  call foo (42, p, q, omp_null_allocator, 3);
+  call foo (42, p, q, omp_default_mem_alloc, 2);
   call omp_destroy_allocator (a);
 end