Incorrect implicit data-sharing for nested tasks

Summary:
There is a minor issue in how the implicit data-sharings for nested tasks are computed.

For the following example:
```
int x;
#pragma omp task shared(x)
#pragma omp task
x++;
```
We compute an implicit data-sharing of shared for `x` in the second task although I think that it should be firstprivate. Below you can find the part of the OpenMP spec that covers this example:
- // In a task generating construct, if no default clause is present, a variable for which the data-sharing attribute is not determined by the rules above and that in the enclosing context is determined to be shared by all implicit tasks bound to the current team is shared.//
- //In a task generating construct, if no default clause is present, a variable for which the data-sharing attribute is not determined by the rules above is firstprivate.//

Since each implicit-task has its own copy of `x`, we shouldn't apply the first rule.

Reviewers: ABataev

Reviewed By: ABataev

Subscribers: cfe-commits, rogfer01

Tags: #openmp

Differential Revision: https://reviews.llvm.org/D56430

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@350734 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaOpenMP.cpp b/lib/Sema/SemaOpenMP.cpp
index 140ccd15bbe2175adc1c853cc3d607fddf24a92a..1166de752e395a5edd7b28acdd66c77758eb016f 100644 (file)
--- a/lib/Sema/SemaOpenMP.cpp
+++ b/lib/Sema/SemaOpenMP.cpp
@@ -676,9 +676,13 @@ public:
   }
 
 };
-bool isParallelOrTaskRegion(OpenMPDirectiveKind DKind) {
-  return isOpenMPParallelDirective(DKind) || isOpenMPTaskingDirective(DKind) ||
-         isOpenMPTeamsDirective(DKind) || DKind == OMPD_unknown;
+
+bool isImplicitTaskingRegion(OpenMPDirectiveKind DKind) {
+  return isOpenMPParallelDirective(DKind) || isOpenMPTeamsDirective(DKind);
+}
+
+bool isImplicitOrExplicitTaskingRegion(OpenMPDirectiveKind DKind) {
+  return isImplicitTaskingRegion(DKind) || isOpenMPTaskingDirective(DKind) || DKind == OMPD_unknown;
 }
 
 } // namespace
@@ -819,7 +823,7 @@ DSAStackTy::DSAVarData DSAStackTy::getDSA(iterator &Iter,
           DVar.CKind = OMPC_firstprivate;
           return DVar;
         }
-      } while (I != E && !isParallelOrTaskRegion(I->Directive));
+      } while (I != E && !isImplicitTaskingRegion(I->Directive));
       DVar.CKind =
           (DVarTemp.CKind == OMPC_unknown) ? OMPC_firstprivate : OMPC_shared;
       return DVar;
@@ -1066,7 +1070,7 @@ bool DSAStackTy::isOpenMPLocal(VarDecl *D, iterator Iter) const {
   if (!isStackEmpty()) {
     iterator I = Iter, E = Stack.back().first.rend();
     Scope *TopScope = nullptr;
-    while (I != E && !isParallelOrTaskRegion(I->Directive) &&
+    while (I != E && !isImplicitOrExplicitTaskingRegion(I->Directive) &&
            !isOpenMPTargetExecutionDirective(I->Directive))
       ++I;
     if (I == E)
@@ -1292,7 +1296,7 @@ DSAStackTy::hasDSA(ValueDecl *D,
   if (FromParent && I != EndI)
     std::advance(I, 1);
   for (; I != EndI; std::advance(I, 1)) {
-    if (!DPred(I->Directive) && !isParallelOrTaskRegion(I->Directive))
+    if (!DPred(I->Directive) && !isImplicitOrExplicitTaskingRegion(I->Directive))
       continue;
     iterator NewI = I;
     DSAVarData DVar = getDSA(NewI, D);
@@ -1636,7 +1640,7 @@ VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) {
     auto &&Info = DSAStack->isLoopControlVariable(D);
     if (Info.first ||
         (VD && VD->hasLocalStorage() &&
-         isParallelOrTaskRegion(DSAStack->getCurrentDirective())) ||
+         isImplicitOrExplicitTaskingRegion(DSAStack->getCurrentDirective())) ||
         (VD && DSAStack->isForceVarCapturing()))
       return VD ? VD : Info.second;
     DSAStackTy::DSAVarData DVarPrivate =
@@ -2244,7 +2248,7 @@ public:
       // attribute, must have its data-sharing attribute explicitly determined
       // by being listed in a data-sharing attribute clause.
       if (DVar.CKind == OMPC_unknown && Stack->getDefaultDSA() == DSA_none &&
-          isParallelOrTaskRegion(DKind) &&
+          isImplicitOrExplicitTaskingRegion(DKind) &&
           VarsWithInheritedDSA.count(VD) == 0) {
         VarsWithInheritedDSA[VD] = E;
         return;

diff --git a/test/OpenMP/task_messages.cpp b/test/OpenMP/task_messages.cpp
index 85072cb5b43c6997fa92b80c809fca8965e9f425..d490c7f8ea489d7240f2bfaafa94ab659ab7e35a 100644 (file)
--- a/test/OpenMP/task_messages.cpp
+++ b/test/OpenMP/task_messages.cpp
@@ -8,7 +8,7 @@ void foo() {
 #pragma omp task // expected-error {{unexpected OpenMP directive '#pragma omp task'}}
 
 class S {
-  S(const S &s) { a = s.a + 12; } // expected-note 14 {{implicitly declared private here}}
+  S(const S &s) { a = s.a + 12; } // expected-note 16 {{implicitly declared private here}}
   int a;
 
 public:
@@ -50,6 +50,15 @@ int foo() {
   // expected-error@+1 {{calling a private constructor of class 'S'}}
   ++a; // expected-error {{calling a private constructor of class 'S'}}
 #pragma omp task default(shared)
+#pragma omp task
+  // expected-error@+1 {{calling a private constructor of class 'S'}}
+  ++a;
+#pragma omp parallel shared(a)
+#pragma omp task
+#pragma omp task
+  ++a;
+#pragma omp parallel shared(a)
+#pragma omp task default(shared)
 #pragma omp task
   ++a;
 #pragma omp task
@@ -204,6 +213,15 @@ L2:
   // expected-error@+1 {{calling a private constructor of class 'S'}}
   ++sa; // expected-error {{calling a private constructor of class 'S'}}
 #pragma omp task default(shared)
+#pragma omp task
+  // expected-error@+1 {{calling a private constructor of class 'S'}}
+  ++sa;
+#pragma omp parallel shared(sa)
+#pragma omp task
+#pragma omp task
+  ++sa;
+#pragma omp parallel shared(sa)
+#pragma omp task default(shared)
 #pragma omp task
   ++sa;
 #pragma omp task