[Flang][OpenMP 4.5] Add semantic check for OpenMP Do Loop Constructs for Threadprivate

[yhegde]

Summary

Semantic check for OpenMP 4.5 - 2.7.1 Do Loop restrictions for Threadprivate.
Implementation of Do loop threadprivate check.

This PR is created based on the review comments on the review PR https://reviews.llvm.org/D92732

File:
resolve-directives.cpp

Tescases:
omp-do04.f90
omp-do04-positivecase.f90

[yhegde]

@kiranchandramohan , I was working with the following test case you have given ,

module md
integer :: i
!$omp threadprivate(i)
end module

program mn
use md
!$omp do
do i = 1, 10

do j = 1, 10
  print *, "Hello"
end do

end do
!$omp end do
end program
+++++++++++++++++++++++++++

The threadPrivateSymbol will get reset once the subroutine called up and it is set as OmpPredetermined and OmpPrivate and adjusted with in the DO loop region and it seems calling DeclareOrMarkOtherAccessEntity to set the Symbol flag to OmpThreadprivate and I think MakeAssocSymbol called with OmpPrivate to create HostAssocDetails. Then I am getting the symbol from HostAssocDtails and then checking whether it is OmpThreadprivate . Its working and throwing the following err.

./tpmodule.f90:9:4: error: Loop iteration variable i is not allowed in THREADPRIVATE.

do i = 1, 10 
   ^

if this is the case , I suppose no where I need to call ClearThreadPrivateSymbols() because all the symbols in the threadPrivateSymbols are reset and new symbols get generated ( local copies probably ). Do you think I am missing anything ? Is this ok ? Please let me know. Thank you.

[yhegde]

In D96686#2565173, @yhegde wrote:

@kiranchandramohan , I was working with the following test case you have given ,

module md
integer :: i
!$omp threadprivate(i)
end module

program mn
use md
!$omp do
do i = 1, 10

do j = 1, 10
  print *, "Hello"
end do

end do
!$omp end do
end program
+++++++++++++++++++++++++++

The threadPrivateSymbol will get reset once the subroutine called up and it is set as OmpPredetermined and OmpPrivate and adjusted with in the DO loop region and it seems calling DeclareOrMarkOtherAccessEntity to set the Symbol flag to OmpThreadprivate and I think MakeAssocSymbol called with OmpPrivate to create HostAssocDetails. Then I am getting the symbol from HostAssocDtails and then checking whether it is OmpThreadprivate . Its working and throwing the following err.

./tpmodule.f90:9:4: error: Loop iteration variable i is not allowed in THREADPRIVATE.

do i = 1, 10 
   ^

if this is the case , I suppose no where I need to call ClearThreadPrivateSymbols() because all the symbols in the threadPrivateSymbols are reset and new symbols get generated ( local copies probably ). Do you think I am missing anything ? Is this ok ? Please let me know. Thank you.

But this code does not work if module.f90 contains
module md
integer :: i
!$omp threadprivate(i)
end module

and tp.f90 uses that module - like
program mn
use md
!$omp do
do i = 1, 10

do j = 1, 10
  print *, "Hello"
end do

end do
!$omp end do
end program

But gfortran gives error.

[yhegde]

It works for the following case.

module tp

integer i
!$omp threadprivate(i)

end module tp

module usetp

use tp

end module usetp

program main

use usetp

!$omp do
do i = 1, 10

do j = 1, 10
  print *, "Hello"
end do

end do
!$omp end do
end program

Error msg
./module.f90:14:4: error: Loop iteration variable i is not allowed in THREADPRIVATE.

do i = 1, 10
   ^

[yhegde]

Patch updated and rebased to check Threadprivate variables in do loops , across the modules.

[kiranchandramohan]

LGTM. Yes, using the symbol is the right way here.
Thanks @yhegde for separating this out into a new patch. Thanks also for you patience and all your work for semantic checks for OpenMP.

[yhegde]

In D96686#2610323, @kiranchandramohan wrote:

LGTM. Yes, using the symbol is the right way here.
Thanks @yhegde for separating this out into a new patch. Thanks also for you patience and all your work for semantic checks for OpenMP.

Thank you @kiranchandramohan for the review comments. That was a good opportunity to understand flang and it was nice working with you.

flang/lib/Semantics/resolve-directives.cpp

void CheckPrivateDSAObject(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void CheckSourceLabel(const parser::Label &);
   void CheckLabelContext(const parser::CharBlock, const parser::CharBlock,
       std::optional<DirContext>, std::optional<DirContext>);
   void ClearLabels() {
     sourceLabels_.clear();
     targetLabels_.clear();
   };
+
   bool HasSymbolInEnclosingScope(const Symbol &, Scope &);
+  std::int64_t ordCollapseLevel{0};
 };
 
 template <typename T>
 bool DirectiveAttributeVisitor<T>::HasDataSharingAttributeObject(
     const Symbol &object) {
   auto it{dataSharingAttributeObjects_.find(object)};
   return it != dataSharingAttributeObjects_.end();
 }
if (beginDir.v == llvm::omp::Directive::OMPD_do) {
     if (const auto &doConstruct{
             std::get<std::optional<parser::DoConstruct>>(x.t)}) {
       if (doConstruct.value().IsDoWhile()) {
         return true;
       }
     }
   }
   PrivatizeAssociatedLoopIndexAndCheckLoopLevel(x);
+  ordCollapseLevel = GetAssociatedLoopLevelFromClauses(clauseList) + 1;
   return true;
 }
 
 void OmpAttributeVisitor::ResolveSeqLoopIndexInParallelOrTaskConstruct(
     const parser::Name &iv) {
   auto targetIt{dirContext_.rbegin()};
   for (;; ++targetIt) {
     if (targetIt == dirContext_.rend()) {
bool OmpAttributeVisitor::Pre(const parser::DoConstruct &x) {
   if (x.IsDoNormal()) {
     if (!dirContext_.empty() && GetContext().withinConstruct) {
       if (const auto &iv{GetLoopIndex(x)}; iv.symbol) {
         if (!iv.symbol->test(Symbol::Flag::OmpPreDetermined)) {
           ResolveSeqLoopIndexInParallelOrTaskConstruct(iv);
         } else {
           // TODO: conflict checks with explicitly determined DSA
         }
+        ordCollapseLevel--;
+        if (ordCollapseLevel) {
+          if (const auto *details{iv.symbol->detailsIf<HostAssocDetails>()}) {
+            const Symbol *tpSymbol = &details->symbol();
+            if (tpSymbol->test(Symbol::Flag::OmpThreadprivate)) {
+              context_.Say(iv.source,
+                  "Loop iteration variable %s is not allowed in THREADPRIVATE."_err_en_US,
+                  iv.ToString());
+            }
+          }
+        }
       }
     }
   }
   return true;
 }
 
 std::int64_t OmpAttributeVisitor::GetAssociatedLoopLevelFromClauses(
     const parser::OmpClauseList &x) {

flang/test/Semantics/omp-do04-positivecase.f90

+! RUN: %S/test_symbols.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.7.1 Do Loop Constructs
+
+!DEF: /omp_do1 MainProgram
+program omp_do1
+  !DEF: /omp_do1/i ObjectEntity INTEGER(4)
+  !DEF: /omp_do1/j ObjectEntity INTEGER(4)
+  !DEF: /omp_do1/k (OmpThreadprivate) ObjectEntity INTEGER(4)
+  !DEF: /omp_do1/n (OmpThreadprivate) ObjectEntity INTEGER(4)
+  integer i, j, k, n
+  !$omp threadprivate (k,n)
+  !$omp do
+  !DEF: /omp_do1/Block1/i (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+  do i=1,10
+    !REF: /omp_do1/j
+    do j=1,10
+      print *, "Hello"
+    end do
+  end do
+  !$omp end do
+end program omp_do1

flang/test/Semantics/omp-do04.f90

-! RUN: %S/test_errors.sh %s %t %flang -fopenmp
-! XFAIL: *
-
+! RUN: %S/test_errors.sh %s %t %f18 -fopenmp
 ! OpenMP Version 4.5
 ! 2.7.1 Loop Construct
 ! The loop iteration variable may not appear in a threadprivate directive.
 
+
 program omp_do
-  integer i, j, k
+  integer, save:: i, j, k,n
+  !$omp  threadprivate(k,j,i)
+  !$omp  do collapse(2)
+  !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
+  do i = 1, 10
+    !ERROR: Loop iteration variable j is not allowed in THREADPRIVATE.
+    do j = 1, 10
+      print *, "Hello"
+    end do
+  end do
+  !$omp end do
+end program omp_do
 
-  !$omp do firstprivate(i)
-  !ERROR: !$OMP DO iteration variable i is not allowed in threadprivate
+program omp_do1
+  !$omp  threadprivate(k,j,i)
+  !$omp  do
+  !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
   do i = 1, 10
     do j = 1, 10
       print *, "Hello"
     end do
   end do
   !$omp end do
 
-end program omp_do
+end program omp_do1
+
+program omp_do2
+  !$omp threadprivate(k)
+  !$omp threadprivate(j)
+  call compute()
+  contains
+  subroutine compute()
+  !$omp  do ordered(1) collapse(1)
+  !ERROR: Loop iteration variable k is not allowed in THREADPRIVATE.
+  foo: do k = 1, 10
+    do i = 1, 10
+      print *, "Hello"
+    end do
+  end do foo
+  !$omp end do
+  end subroutine
+
+end program omp_do2
+
+program omp_do3
+  !$omp  threadprivate(i)
+  !$omp parallel
+  print *, "parallel"
+  !$omp end parallel
+  !$omp  do
+  !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
+  do i = 1, 10
+    do j = 1, 10
+      print *, "Hello"
+    end do
+  end do
+  !$omp end do
+
+end program omp_do3
+
+module tp
+  !integer i,j
+  integer, save:: i, j, k,n
+  !$omp threadprivate(i)
+  !$omp threadprivate(j)
+end module tp
+
+module usetp
+  use tp
+end module usetp
+
+program main
+  use usetp
+  !$omp  do
+  !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
+  do i = 1, 10
+    do j = 1, 10
+      print *, "Hello"
+    end do
+  end do
+  !$omp end do
+end program
+
+program main1
+  use tp
+  !$omp  do
+  !ERROR: Loop iteration variable j is not allowed in THREADPRIVATE.
+  do j = 1, 10
+    do i = 1, 10
+      print *, "Hello"
+    end do
+  end do
+  !$omp end do
+end program