[flang][OpenMP] Added test case for OpenMP 5.0 specification based semantic checks for parallel sections construct

[NimishMishra]

Summary

Parallel sections directive borrows the semantic checks from both sections directive and parallel directive. Semantic checks for both are merged in main branch; this test case is added to make sure correct semantic checks upon merging the two.

[kiranchandramohan]

LGTM.

I think the commit message can be improved. If this covers only the checks that were added in a previous patch please mention that.

flang/test/Semantics/omp-parallel-sections01.f90

+! RUN: %python %S/test_errors.py %s %flang -fopenmp
+! OpenMP version 5.0.0
+! 2.13.3 parallel sections Construct
+! The restrictions for the parallel construct and the sections construct apply
+program OmpConstructSections01
+   use omp_lib
+   integer :: section_count = 0
+   integer, parameter :: NT = 4
+   integer :: i, array(10)
+   type my_type
+      integer :: array(10)
+   end type my_type
+   type(my_type) :: my_var
+   print *, 'section_count', section_count
+   do i = 1, 10
+      array(i) = i
+   end do
+!ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a PRIVATE or SHARED clause
+!$omp parallel sections shared(array(i))
+!$omp end parallel sections
+!ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a PRIVATE or SHARED clause
+!$omp parallel sections shared(my_var%array)
+!$omp end parallel sections
+
+!ERROR: invalid branch into an OpenMP structured block
+!ERROR: invalid branch into an OpenMP structured block
+!ERROR: invalid branch into an OpenMP structured block
+   if (NT) 20, 30, 40
+!ERROR: invalid branch into an OpenMP structured block
+   goto 20
+!ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a PRIVATE or SHARED clause
+!$omp parallel sections private(my_var%array)
+   !$omp section
+   print *, "This is a single statement structured block"
+   !$omp section
+   open (10, file="random-file-name.txt", err=30)
+   !ERROR: invalid branch into an OpenMP structured block
+   !ERROR: invalid branch leaving an OpenMP structured block
+   open (10, file="random-file-name.txt", err=40)
+   !$omp section
+   section_count = section_count + 1
+20 print *, 'Entering into section'
+   call calledFromWithinSection()
+   print *, 'section_count', section_count
+   !$omp section
+   section_count = section_count + 1
+   print *, 'section_count', section_count
+   !ERROR: invalid branch leaving an OpenMP structured block
+   goto 10
+   !$omp section
+30 print *, "Error in opening file"
+!$omp end parallel sections
+10 print *, 'Jump from section'
+!ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a PRIVATE or SHARED clause
+!$omp parallel sections private(array(i))
+   !$omp section
+40 print *, 'Error in opening file'
+!$omp end parallel sections
+end program OmpConstructSections01
+
+function returnFromSections()
+   !$omp parallel sections
+   !$omp section
+   !ERROR: RETURN statement is not allowed in a PARALLEL SECTIONS construct
+   RETURN
+   !$omp end parallel sections
+end function
+
+subroutine calledFromWithinSection()
+   print *, "I am called from within a 'section' structured block"
+   return
+end subroutine calledFromWithinSection
+
+subroutine continueWithinSections()
+   integer i
+   do i = 1, 10
+      print *, "Statement within loop but outside section construct"
+      !$omp parallel sections
+      !$omp section
+      IF (i .EQ. 5) THEN
+         !ERROR: CYCLE to construct outside of PARALLEL SECTIONS construct is not allowed
+         CYCLE
+      END IF
+      !$omp end parallel sections
+      print *, "Statement within loop but outside section contruct"
+   end do
+
+   !$omp parallel sections
+   !$omp section
+   do i = 1, 10
+      CYCLE
+   end do
+   !$omp end parallel sections
+
+   !$omp parallel sections
+   !$omp section
+   loop_1: do i = 1, 10
+      IF (i .EQ. 5) THEN
+         CYCLE loop_1
+      END IF
+   end do loop_1
+   !$omp end parallel sections
+
+   loop_2: do i = 1, 10
+      !$omp parallel sections
+      !$omp section
+      IF (i .EQ. 5) THEN
+         !ERROR: CYCLE to construct 'loop_2' outside of PARALLEL SECTIONS construct is not allowed
+         CYCLE loop_2
+      END IF
+      !$omp end parallel sections
+   end do loop_2
+end subroutine continueWithinSections
+
+subroutine breakWithinSections()
+   loop_3: do i = 1, 10
+      !$omp parallel sections
+      !$omp section
+      IF (i .EQ. 5) THEN
+         !ERROR: EXIT to construct 'loop_3' outside of PARALLEL SECTIONS construct is not allowed
+         EXIT loop_3
+      END IF
+      !$omp end parallel sections
+   end do loop_3
+
+   loop_4: do i = 1, 10
+      !$omp parallel sections
+      !$omp section
+      IF (i .EQ. 5) THEN
+         !ERROR: EXIT to construct outside of PARALLEL SECTIONS construct is not allowed
+         EXIT
+      END IF
+      !$omp end parallel sections
+   end do loop_4
+
+   !$omp parallel sections
+   !$omp section
+   do i = 1, 10
+      IF (i .EQ. 5) THEN
+         EXIT
+      END IF
+   end do
+   !$omp end parallel sections
+
+   !$omp parallel sections
+   !$omp section
+   loop_5: do i = 1, 10
+      IF (i .EQ. 5) THEN
+         EXIT loop_5
+      END IF
+   end do loop_5
+   !$omp end parallel sections
+end subroutine breakWithinSections