Revert "[OPENMP]Fix PR41767: diagnose DSA for variables in clauses with default(none)."

This implementation isn't sound as per the standard.
It erroneously diagnoses e.g. the following case:
```
$ cat test.cpp
void f(int n) {
 #pragma omp parallel default(none) if(n)
    ;
}
```
```
$ ./bin/clang -fopenmp test.cpp
test.cpp:2:40: error: variable 'n' must have explicitly specified data sharing attributes
 #pragma omp parallel default(none) if(n)
                                       ^
test.cpp:2:31: note: explicit data sharing attribute requested here
 #pragma omp parallel default(none) if(n)
                              ^
1 error generated.
```

As per OpenMP Application Programming Interface Version 5.0 November 2018:
* 2.19.4.1default Clause
  The default clause explicitly determines the data-sharing attributes of
  variables that are referenced *in a parallel, teams, or task generating
  construct and would otherwise be implicitly determined
  (see Section 2.19.1.1 on page 270).
* 2.6.1 Determining the Number of Threads for a parallel Region
  Using a variable in an if or num_threads clause expression of a parallel
  construct causes an implicit reference to the variable in all enclosing
  constructs. The if clause expression and the num_threads clause expression
  are evaluated in the context outside of the parallel construct,

This reverts commit r360073.

llvm-svn: 360326

1 files changed, 3 insertions, 96 deletions

diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index c6c3a6b5901..276f1506c4b 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -750,8 +750,7 @@ bool isImplicitTaskingRegion(OpenMPDirectiveKind DKind) {
 }
 
 bool isImplicitOrExplicitTaskingRegion(OpenMPDirectiveKind DKind) {
-  return isImplicitTaskingRegion(DKind) || isOpenMPTaskingDirective(DKind) ||
-         DKind == OMPD_unknown;
+  return isImplicitTaskingRegion(DKind) || isOpenMPTaskingDirective(DKind) || DKind == OMPD_unknown;
 }
 
 } // namespace
@@ -2561,17 +2560,9 @@ public:
         E->containsUnexpandedParameterPack() || E->isInstantiationDependent())
       return;
     if (auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
-      // Check the datasharing rules for the expressions in the clauses.
-      if (!CS) {
-        if (auto *CED = dyn_cast<OMPCapturedExprDecl>(VD))
-          if (!CED->hasAttr<OMPCaptureNoInitAttr>()) {
-            Visit(CED->getInit());
-            return;
-          }
-      }
       VD = VD->getCanonicalDecl();
       // Skip internally declared variables.
-      if (VD->hasLocalStorage() && CS && !CS->capturesVariable(VD))
+      if (VD->hasLocalStorage() && !CS->capturesVariable(VD))
         return;
 
       DSAStackTy::DSAVarData DVar = Stack->getTopDSA(VD, /*FromParent=*/false);
@@ -2582,7 +2573,7 @@ public:
       // Skip internally declared static variables.
       llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
           OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD);
-      if (VD->hasGlobalStorage() && CS && !CS->capturesVariable(VD) &&
+      if (VD->hasGlobalStorage() && !CS->capturesVariable(VD) &&
           (!Res || *Res != OMPDeclareTargetDeclAttr::MT_Link))
         return;
 
@@ -4195,90 +4186,6 @@ StmtResult Sema::ActOnOpenMPExecutableDirective(
 
   ErrorFound = Res.isInvalid() || ErrorFound;
 
-  // Check variables in the clauses if default(none) was specified.
-  if (DSAStack->getDefaultDSA() == DSA_none) {
-    DSAAttrChecker DSAChecker(DSAStack, *this, nullptr);
-    for (OMPClause *C : Clauses) {
-      switch (C->getClauseKind()) {
-      case OMPC_num_threads:
-      case OMPC_dist_schedule:
-        // Do not analyse if no parent teams directive.
-        if (isOpenMPTeamsDirective(DSAStack->getCurrentDirective()))
-          break;
-        continue;
-      case OMPC_if:
-        if ((isOpenMPTeamsDirective(DSAStack->getCurrentDirective()) &&
-             cast<OMPIfClause>(C)->getNameModifier() != OMPD_target) ||
-            isOpenMPParallelDirective(DSAStack->getCurrentDirective()))
-          break;
-        continue;
-      case OMPC_schedule:
-        break;
-      case OMPC_ordered:
-      case OMPC_device:
-      case OMPC_num_teams:
-      case OMPC_thread_limit:
-      case OMPC_priority:
-      case OMPC_grainsize:
-      case OMPC_num_tasks:
-      case OMPC_hint:
-      case OMPC_collapse:
-      case OMPC_safelen:
-      case OMPC_simdlen:
-      case OMPC_final:
-      case OMPC_default:
-      case OMPC_proc_bind:
-      case OMPC_private:
-      case OMPC_firstprivate:
-      case OMPC_lastprivate:
-      case OMPC_shared:
-      case OMPC_reduction:
-      case OMPC_task_reduction:
-      case OMPC_in_reduction:
-      case OMPC_linear:
-      case OMPC_aligned:
-      case OMPC_copyin:
-      case OMPC_copyprivate:
-      case OMPC_nowait:
-      case OMPC_untied:
-      case OMPC_mergeable:
-      case OMPC_allocate:
-      case OMPC_read:
-      case OMPC_write:
-      case OMPC_update:
-      case OMPC_capture:
-      case OMPC_seq_cst:
-      case OMPC_depend:
-      case OMPC_threads:
-      case OMPC_simd:
-      case OMPC_map:
-      case OMPC_nogroup:
-      case OMPC_defaultmap:
-      case OMPC_to:
-      case OMPC_from:
-      case OMPC_use_device_ptr:
-      case OMPC_is_device_ptr:
-        continue;
-      case OMPC_allocator:
-      case OMPC_flush:
-      case OMPC_threadprivate:
-      case OMPC_uniform:
-      case OMPC_unknown:
-      case OMPC_unified_address:
-      case OMPC_unified_shared_memory:
-      case OMPC_reverse_offload:
-      case OMPC_dynamic_allocators:
-      case OMPC_atomic_default_mem_order:
-        llvm_unreachable("Unexpected clause");
-      }
-      for (Stmt *CC : C->children()) {
-        if (CC)
-          DSAChecker.Visit(CC);
-      }
-    }
-    for (auto &P : DSAChecker.getVarsWithInheritedDSA())
-      VarsWithInheritedDSA[P.getFirst()] = P.getSecond();
-  }
   for (const auto &P : VarsWithInheritedDSA) {
     Diag(P.second->getExprLoc(), diag::err_omp_no_dsa_for_variable)
         << P.first << P.second->getSourceRange();