[OPENMP] issue error messages for multiple teams contructs in a target constructs

[kkwli0]

Summary

The compiler does not generate any error messages if there are more than one teams construct inside a target constructs.

#pragma omp target
{
  #pragma omp teams
  {  ...  }

  #pragma omp teams
  { ... }
}

After the fix, the error messages are issued.

teams.c:4:9: error: target construct with nested teams region contains statements
      outside of the teams construct
#pragma omp target
        ^
teams.c:14:11: note: nested teams construct here
  #pragma omp teams
          ^
teams.c:9:11: note: directive outside teams construct here
  #pragma omp teams
          ^
1 error generated.

[ABataev]

clang/lib/Sema/SemaOpenMP.cpp

7070–7072

just if (!OED || !isOpenMPTeamsDirective(OED->getDirectiveKind() || OMPTeamsFound)

[kkwli0]

clang/lib/Sema/SemaOpenMP.cpp

7070–7072

Yep, it simplifies the logic.

[kkwli0]

Update based on review comment.

[ABataev]

LG

[kkwli0]

Committed: r353186

clang/lib/Sema/SemaOpenMP.cpp

StmtResult Sema::ActOnOpenMPTargetDirective(ArrayRef<OMPClause *> Clauses,
   // outside of the teams construct.
   if (DSAStack->hasInnerTeamsRegion()) {
     const Stmt *S = CS->IgnoreContainers(/*IgnoreCaptured=*/true);
     bool OMPTeamsFound = true;
     if (const auto *CS = dyn_cast<CompoundStmt>(S)) {
       auto I = CS->body_begin();
       while (I != CS->body_end()) {
         const auto *OED = dyn_cast<OMPExecutableDirective>(*I);
-        if (!OED || !isOpenMPTeamsDirective(OED->getDirectiveKind())) {
+        if (!OED || !isOpenMPTeamsDirective(OED->getDirectiveKind()) ||
+            OMPTeamsFound) {
+
           OMPTeamsFound = false;
           break;
         }
         ++I;
       }
       assert(I != CS->body_end() && "Not found statement");
       S = *I;
     } else {

clang/test/OpenMP/nesting_of_regions.cpp

for (int i = 0; i < 10; ++i)
     ;
 #pragma omp target
   {
 #pragma omp teams
     ++a;
   }
 #pragma omp target // expected-error {{target construct with nested teams region contains statements outside of the teams construct}}
   {
+#pragma omp teams // expected-note {{directive outside teams construct here}}
+    ++a;
+#pragma omp teams // expected-note {{nested teams construct here}}
+    ++a;
+  }
+#pragma omp target // expected-error {{target construct with nested teams region contains statements outside of the teams construct}}
+  {
     ++a;           // expected-note {{statement outside teams construct here}}
 #pragma omp teams  // expected-note {{nested teams construct here}}
     ++a;
   }
 #pragma omp target // expected-error {{target construct with nested teams region contains statements outside of the teams construct}}
   {
     while (0)      // expected-note {{statement outside teams construct here}}
 #pragma omp teams  // expected-note {{nested teams construct here}}
#pragma omp target exit data map(from: a) // expected-error {{region cannot be nested inside 'target' region}}
   }
 #pragma omp target
   {
 #pragma omp teams
     ++a;
   }
 #pragma omp target // expected-error {{target construct with nested teams region contains statements outside of the teams construct}}
   {
+#pragma omp teams // expected-note {{directive outside teams construct here}}
+    ++a;
+#pragma omp teams // expected-note {{nested teams construct here}}
+    ++a;
+  }
+#pragma omp target // expected-error {{target construct with nested teams region contains statements outside of the teams construct}}
+  {
     ++a;          // expected-note {{statement outside teams construct here}}
 #pragma omp teams // expected-note {{nested teams construct here}}
     ++a;
   }
 #pragma omp target
   {
 #pragma omp taskloop
   for (int i = 0; i < 10; ++i)