[OPENMP5.1] Initial support for message clause.

[jyu2]

Summary

Initial support for message clause.

[ABataev]

clang/lib/Sema/SemaOpenMP.cpp

11046

Use real type instead of auto

[jyu2]

Thanks Alexey for the review. Address his comment.

clang/lib/Sema/SemaOpenMP.cpp

11046

Thanks. How about using getSingleClause.

[ABataev]

LG

[jyu2]

checked with 9d90cf2fca44

clang/include/clang/AST/OpenMPClause.h

const_child_range used_children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   static bool classof(const OMPClause *T) {
     return T->getClauseKind() == llvm::omp::OMPC_severity;
   }
 };
 
+/// This represents 'message' clause in the '#pragma omp error' directive
+///
+/// \code
+/// #pragma omp error message("GNU compiler required.")
+/// \endcode
+/// In this example directive '#pragma omp error' has simple
+/// 'message' clause with user error message of "GNU compiler required.".
+class OMPMessageClause final : public OMPClause {
+  friend class OMPClauseReader;
+
+  /// Location of '('
+  SourceLocation LParenLoc;
+
+  // Expression of the 'message' clause.
+  Stmt *MessageString = nullptr;
+
+  /// Set message string of the clause.
+  void setMessageString(Expr *MS) { MessageString = MS; }
+
+  /// Sets the location of '('.
+  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }
+
+public:
+  /// Build 'message' clause with message string argument
+  ///
+  /// \param A Argument of the clause (message string).
+  /// \param StartLoc Starting location of the clause.
+  /// \param LParenLoc Location of '('.
+  /// \param EndLoc Ending location of the clause.
+  OMPMessageClause(Expr *MS, SourceLocation StartLoc, SourceLocation LParenLoc,
+                   SourceLocation EndLoc)
+      : OMPClause(llvm::omp::OMPC_message, StartLoc, EndLoc),
+        LParenLoc(LParenLoc), MessageString(MS) {}
+
+  /// Build an empty clause.
+  OMPMessageClause()
+      : OMPClause(llvm::omp::OMPC_message, SourceLocation(), SourceLocation()) {
+  }
+
+  /// Returns the locaiton of '('.
+  SourceLocation getLParenLoc() const { return LParenLoc; }
+
+  /// Returns message string of the clause.
+  Expr *getMessageString() const { return cast_or_null<Expr>(MessageString); }
+
+  child_range children() {
+    return child_range(&MessageString, &MessageString + 1);
+  }
+
+  const_child_range children() const {
+    return const_child_range(&MessageString, &MessageString + 1);
+  }
+
+  child_range used_children() {
+    return child_range(child_iterator(), child_iterator());
+  }
+
+  const_child_range used_children() const {
+    return const_child_range(const_child_iterator(), const_child_iterator());
+  }
+
+  static bool classof(const OMPClause *T) {
+    return T->getClauseKind() == llvm::omp::OMPC_message;
+  }
+};
+
 /// This represents 'schedule' clause in the '#pragma omp ...' directive.
 ///
 /// \code
 /// #pragma omp for schedule(static, 3)
 /// \endcode
 /// In this example directive '#pragma omp for' has 'schedule' clause with
 /// arguments 'static' and '3'.
 class OMPScheduleClause : public OMPClause, public OMPClauseWithPreInit {

clang/include/clang/AST/RecursiveASTVisitor.h

 }
 
 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::VisitOMPSeverityClause(OMPSeverityClause *) {
   return true;
 }
 
 template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPMessageClause(OMPMessageClause *C) {
+  TRY_TO(TraverseStmt(C->getMessageString()));
+  return true;
+}
+
+template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::VisitOMPScheduleClause(OMPScheduleClause *C) {
   TRY_TO(VisitOMPClauseWithPreInit(C));
   TRY_TO(TraverseStmt(C->getChunkSize()));
   return true;
 }
 
 template <typename Derived>

clang/include/clang/Basic/DiagnosticParseKinds.td

 def warn_pragma_expected_colon_r_paren : Warning<
   "missing ':' or ')' after %0 - ignoring">, InGroup<IgnoredPragmas>;
 def err_omp_unknown_directive : Error<
   "expected an OpenMP directive">;
 def err_omp_unexpected_directive : Error<
   "unexpected OpenMP directive %select{|'#pragma omp %1'}0">;
 def err_omp_expected_punc : Error<
   "expected ',' or ')' in '%0' %select{clause|directive}1">;
+def warn_clause_expected_string : Warning<
+  "expected string literal in 'clause %0' - ignoring">, InGroup<IgnoredPragmas>;
 def err_omp_unexpected_clause : Error<
   "unexpected OpenMP clause '%0' in directive '#pragma omp %1'">;
 def err_omp_immediate_directive : Error<
   "'#pragma omp %0' %select{|with '%2' clause }1cannot be an immediate substatement">;
 def err_omp_expected_identifier_for_critical : Error<
   "expected identifier specifying the name of the 'omp critical' directive">;
 def err_omp_expected_reduction_identifier : Error<
   "expected identifier or one of the following operators: '+', '-', '*', '&', '|', '^', '&&', or '||'">;

clang/include/clang/Sema/Sema.h

public:
 
   /// Called on well-formed 'severity' clause.
   OMPClause *ActOnOpenMPSeverityClause(OpenMPSeverityClauseKind Kind,
                                        SourceLocation KindLoc,
                                        SourceLocation StartLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation EndLoc);
 
+  /// Called on well-formed 'message' clause.
+  /// passing string for message.
+  OMPClause *ActOnOpenMPMessageClause(Expr *MS, SourceLocation StartLoc,
+                                      SourceLocation LParenLoc,
+                                      SourceLocation EndLoc);
+
   /// Data used for processing a list of variables in OpenMP clauses.
   struct OpenMPVarListDataTy final {
     Expr *DepModOrTailExpr = nullptr;
     SourceLocation ColonLoc;
     SourceLocation RLoc;
     CXXScopeSpec ReductionOrMapperIdScopeSpec;
     DeclarationNameInfo ReductionOrMapperId;
     int ExtraModifier = -1; ///< Additional modifier for linear, map, depend or

clang/lib/AST/OpenMPClause.cpp

const OMPClauseWithPreInit *OMPClauseWithPreInit::get(const OMPClause *C) {
   case OMPC_has_device_addr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
   case OMPC_reverse_offload:
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_destroy:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:
const OMPClauseWithPostUpdate *OMPClauseWithPostUpdate::get(const OMPClause *C) {
   case OMPC_has_device_addr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
   case OMPC_reverse_offload:
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_destroy:
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_detach:

 }
 
 void OMPClausePrinter::VisitOMPSeverityClause(OMPSeverityClause *Node) {
   OS << "severity("
      << getOpenMPSimpleClauseTypeName(OMPC_severity, Node->getSeverityKind())
      << ")";
 }
 
+void OMPClausePrinter::VisitOMPMessageClause(OMPMessageClause *Node) {
+  OS << "message(\""
+     << cast<StringLiteral>(Node->getMessageString())->getString().data()
+     << "\")";
+}
+
 void OMPClausePrinter::VisitOMPScheduleClause(OMPScheduleClause *Node) {
   OS << "schedule(";
   if (Node->getFirstScheduleModifier() != OMPC_SCHEDULE_MODIFIER_unknown) {
     OS << getOpenMPSimpleClauseTypeName(OMPC_schedule,
                                         Node->getFirstScheduleModifier());
     if (Node->getSecondScheduleModifier() != OMPC_SCHEDULE_MODIFIER_unknown) {
       OS << ", ";
       OS << getOpenMPSimpleClauseTypeName(OMPC_schedule,

clang/lib/AST/StmtProfile.cpp

 
 void OMPClauseProfiler::VisitOMPAtomicDefaultMemOrderClause(
     const OMPAtomicDefaultMemOrderClause *C) {}
 
 void OMPClauseProfiler::VisitOMPAtClause(const OMPAtClause *C) {}
 
 void OMPClauseProfiler::VisitOMPSeverityClause(const OMPSeverityClause *C) {}
 
+void OMPClauseProfiler::VisitOMPMessageClause(const OMPMessageClause *C) {
+  if (C->getMessageString())
+    Profiler->VisitStmt(C->getMessageString());
+}
+
 void OMPClauseProfiler::VisitOMPScheduleClause(const OMPScheduleClause *C) {
   VistOMPClauseWithPreInit(C);
   if (auto *S = C->getChunkSize())
     Profiler->VisitStmt(S);
 }
 
 void OMPClauseProfiler::VisitOMPOrderedClause(const OMPOrderedClause *C) {
   if (auto *Num = C->getNumForLoops())

clang/lib/CodeGen/CGStmtOpenMP.cpp

static void emitOMPAtomicExpr(CodeGenFunction &CGF, OpenMPClauseKind Kind,
   case OMPC_has_device_addr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
   case OMPC_reverse_offload:
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_destroy:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:

clang/lib/Parse/ParseOpenMP.cpp

OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
   case OMPC_allocator:
   case OMPC_depobj:
   case OMPC_detach:
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_filter:
   case OMPC_partial:
   case OMPC_align:
+  case OMPC_message:
     // OpenMP [2.5, Restrictions]
     //  At most one num_threads clause can appear on the directive.
     // OpenMP [2.8.1, simd construct, Restrictions]
     //  Only one safelen  clause can appear on a simd directive.
     //  Only one simdlen  clause can appear on a simd directive.
     //  Only one collapse clause can appear on a simd directive.
     // OpenMP [2.11.1, task Construct, Restrictions]
     //  At most one if clause can appear on the directive.
case OMPC_message:
     // At most one num_tasks clause can appear on the directive.
     // OpenMP [2.11.3, allocate Directive, Restrictions]
     // At most one allocator clause can appear on the directive.
     // OpenMP 5.0, 2.10.1 task Construct, Restrictions.
     // At most one detach clause can appear on the directive.
     // OpenMP 5.1, 2.3.6 dispatch Construct, Restrictions.
     // At most one novariants clause can appear on a dispatch directive.
     // At most one nocontext clause can appear on a dispatch directive.
+    // OpenMP [5.1, error directive, Restrictions]
+    // At most one message clause can appear on the directive
     if (!FirstClause) {
       Diag(Tok, diag::err_omp_more_one_clause)
           << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
       ErrorFound = true;
     }
 
     if ((CKind == OMPC_ordered || CKind == OMPC_partial) &&
         PP.LookAhead(/*N=*/0).isNot(tok::l_paren))

clang/lib/Sema/SemaOpenMP.cpp

for (OMPClause *C : Clauses) {
       case OMPC_reverse_offload:
       case OMPC_dynamic_allocators:
       case OMPC_atomic_default_mem_order:
       case OMPC_device_type:
       case OMPC_match:
       case OMPC_when:
       case OMPC_at:
       case OMPC_severity:
+      case OMPC_message:
       default:
         llvm_unreachable("Unexpected clause");
       }
       for (Stmt *CC : C->children()) {
         if (CC)
           DSAChecker.Visit(CC);
       }
     }
StmtResult Sema::ActOnOpenMPBarrierDirective(SourceLocation StartLoc,
                                              SourceLocation EndLoc) {
   return OMPBarrierDirective::Create(Context, StartLoc, EndLoc);
 }
 
 StmtResult Sema::ActOnOpenMPErrorDirective(ArrayRef<OMPClause *> Clauses,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc,
                                            bool InExContext) {
-  auto AtClauses =
-      OMPExecutableDirective::getClausesOfKind<OMPAtClause>(Clauses);
-  const OMPAtClause *AtC = AtClauses.empty() ? nullptr : (*AtClauses.begin());
+  const OMPAtClause *AtC =
+      OMPExecutableDirective::getSingleClause<OMPAtClause>(Clauses);
 
   if (AtC && !InExContext && AtC->getAtKind() == OMPC_AT_execution) {
     Diag(AtC->getAtKindKwLoc(), diag::err_omp_unexpected_execution_modifier);
     return StmtError();
   }
-  auto SeverityClauses =
-      OMPExecutableDirective::getClausesOfKind<OMPSeverityClause>(Clauses);
+
   const OMPSeverityClause *SeverityC =
-      SeverityClauses.empty() ? nullptr : (*SeverityClauses.begin());
+      OMPExecutableDirective::getSingleClause<OMPSeverityClause>(Clauses);
+  const OMPMessageClause *MessageC =
+      OMPExecutableDirective::getSingleClause<OMPMessageClause>(Clauses);
+  Expr *ME = MessageC ? MessageC->getMessageString() : nullptr;
 
   if (!AtC || AtC->getAtKind() == OMPC_AT_compilation) {
     if (SeverityC && SeverityC->getSeverityKind() == OMPC_SEVERITY_warning)
       Diag(SeverityC->getSeverityKindKwLoc(), diag::warn_diagnose_if_succeeded)
-          << "WARNING";
+          << (ME ? cast<StringLiteral>(ME)->getString().data() : "WARNING");
     else
-      Diag(StartLoc, diag::err_diagnose_if_succeeded) << "ERROR";
+      Diag(StartLoc, diag::err_diagnose_if_succeeded)
+          << (ME ? cast<StringLiteral>(ME)->getString().data() : "ERROR");
     if (!SeverityC || SeverityC->getSeverityKind() != OMPC_SEVERITY_warning)
       return StmtError();
   }
   return OMPErrorDirective::Create(Context, StartLoc, EndLoc, Clauses);
 }
 
 StmtResult Sema::ActOnOpenMPTaskwaitDirective(ArrayRef<OMPClause *> Clauses,
                                               SourceLocation StartLoc,
case OMPC_nocontext:
     Res = ActOnOpenMPNocontextClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_filter:
     Res = ActOnOpenMPFilterClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_partial:
     Res = ActOnOpenMPPartialClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
+  case OMPC_message:
+    Res = ActOnOpenMPMessageClause(Expr, StartLoc, LParenLoc, EndLoc);
+    break;
   case OMPC_align:
     Res = ActOnOpenMPAlignClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_device:
   case OMPC_if:
   case OMPC_default:
   case OMPC_proc_bind:
   case OMPC_schedule:
static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_destroy:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:
   case OMPC_uses_allocators:
   case OMPC_affinity:
   case OMPC_bind:
   default:
OMPClause *Sema::ActOnOpenMPSimpleClause(
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:
   case OMPC_uses_allocators:
   case OMPC_affinity:
   case OMPC_when:
+  case OMPC_message:
   default:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
 }
 
 static std::string
 getListOfPossibleValues(OpenMPClauseKind K, unsigned First, unsigned Last,
Diag(KindKwLoc, diag::err_omp_unexpected_clause_value)
                                    /*Last=*/OMPC_SEVERITY_unknown)
         << getOpenMPClauseName(OMPC_severity);
     return nullptr;
   }
   return new (Context)
       OMPSeverityClause(Kind, KindKwLoc, StartLoc, LParenLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPMessageClause(Expr *ME, SourceLocation StartLoc,
+                                          SourceLocation LParenLoc,
+                                          SourceLocation EndLoc) {
+  assert(ME && "NULL expr in Message clause");
+  if (!isa<StringLiteral>(ME)) {
+    Diag(ME->getBeginLoc(), diag::warn_clause_expected_string)
+        << getOpenMPClauseName(OMPC_message);
+    return nullptr;
+  }
+  return new (Context) OMPMessageClause(ME, StartLoc, LParenLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPOrderClause(OpenMPOrderClauseKind Kind,
                                         SourceLocation KindKwLoc,
                                         SourceLocation StartLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation EndLoc) {
   if (Kind == OMPC_ORDER_unknown) {
     static_assert(OMPC_ORDER_unknown > 0,
                   "OMPC_ORDER_unknown not greater than 0");
OMPClause *Sema::ActOnOpenMPSingleExprWithArgClause(
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_destroy:
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:
   case OMPC_uses_allocators:
   case OMPC_affinity:
OMPClause *Sema::ActOnOpenMPClause(OpenMPClauseKind Kind,
   case OMPC_has_device_addr:
   case OMPC_atomic_default_mem_order:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
   case OMPC_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_detach:
   case OMPC_inclusive:
   case OMPC_exclusive:
   case OMPC_uses_allocators:
   case OMPC_affinity:
   case OMPC_when:
OMPClause *Sema::ActOnOpenMPVarListClause(OpenMPClauseKind Kind,
   case OMPC_reverse_offload:
   case OMPC_dynamic_allocators:
   case OMPC_atomic_default_mem_order:
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_order:
   case OMPC_at:
   case OMPC_severity:
+  case OMPC_message:
   case OMPC_destroy:
   case OMPC_novariants:
   case OMPC_nocontext:
   case OMPC_detach:
   case OMPC_uses_allocators:
   case OMPC_when:
   case OMPC_bind:
   default:

clang/lib/Sema/TreeTransform.h

OMPClause *RebuildOMPSeverityClause(OpenMPSeverityClauseKind Kind,
                                       SourceLocation KwLoc,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
                                       SourceLocation EndLoc) {
     return getSema().ActOnOpenMPSeverityClause(Kind, KwLoc, StartLoc, LParenLoc,
                                                EndLoc);
   }
 
+  /// Build a new OpenMP 'message' clause.
+  ///
+  /// By default, performs semantic analysis to build the new OpenMP clause.
+  /// Subclasses may override this routine to provide different behavior.
+  OMPClause *RebuildOMPMessageClause(Expr *MS, SourceLocation StartLoc,
+                                     SourceLocation LParenLoc,
+                                     SourceLocation EndLoc) {
+    return getSema().ActOnOpenMPMessageClause(MS, StartLoc, LParenLoc, EndLoc);
+  }
+
   /// Rebuild the operand to an Objective-C \@synchronized statement.
   ///
   /// By default, performs semantic analysis to build the new statement.
   /// Subclasses may override this routine to provide different behavior.
   ExprResult RebuildObjCAtSynchronizedOperand(SourceLocation atLoc,
                                               Expr *object) {
     return getSema().ActOnObjCAtSynchronizedOperand(atLoc, object);
   }

 TreeTransform<Derived>::TransformOMPSeverityClause(OMPSeverityClause *C) {
   return getDerived().RebuildOMPSeverityClause(
       C->getSeverityKind(), C->getSeverityKindKwLoc(), C->getBeginLoc(),
       C->getLParenLoc(), C->getEndLoc());
 }
 
 template <typename Derived>
 OMPClause *
+TreeTransform<Derived>::TransformOMPMessageClause(OMPMessageClause *C) {
+  ExprResult E = getDerived().TransformExpr(C->getMessageString());
+  if (E.isInvalid())
+    return nullptr;
+  return getDerived().RebuildOMPMessageClause(
+      C->getMessageString(), C->getBeginLoc(), C->getLParenLoc(),
+      C->getEndLoc());
+}
+
+template <typename Derived>
+OMPClause *
 TreeTransform<Derived>::TransformOMPPrivateClause(OMPPrivateClause *C) {
   llvm::SmallVector<Expr *, 16> Vars;
   Vars.reserve(C->varlist_size());
   for (auto *VE : C->varlists()) {
     ExprResult EVar = getDerived().TransformExpr(cast<Expr>(VE));
     if (EVar.isInvalid())
       return nullptr;
     Vars.push_back(EVar.get());

clang/lib/Serialization/ASTReader.cpp

case llvm::omp::OMPC_atomic_default_mem_order:
     C = new (Context) OMPAtomicDefaultMemOrderClause();
     break;
   case llvm::omp::OMPC_at:
     C = new (Context) OMPAtClause();
     break;
   case llvm::omp::OMPC_severity:
     C = new (Context) OMPSeverityClause();
     break;
+  case llvm::omp::OMPC_message:
+    C = new (Context) OMPMessageClause();
+    break;
   case llvm::omp::OMPC_private:
     C = OMPPrivateClause::CreateEmpty(Context, Record.readInt());
     break;
   case llvm::omp::OMPC_firstprivate:
     C = OMPFirstprivateClause::CreateEmpty(Context, Record.readInt());
     break;
   case llvm::omp::OMPC_lastprivate:
     C = OMPLastprivateClause::CreateEmpty(Context, Record.readInt());

 }
 
 void OMPClauseReader::VisitOMPSeverityClause(OMPSeverityClause *C) {
   C->setSeverityKind(static_cast<OpenMPSeverityClauseKind>(Record.readInt()));
   C->setLParenLoc(Record.readSourceLocation());
   C->setSeverityKindKwLoc(Record.readSourceLocation());
 }
 
+void OMPClauseReader::VisitOMPMessageClause(OMPMessageClause *C) {
+  C->setMessageString(Record.readSubExpr());
+  C->setLParenLoc(Record.readSourceLocation());
+}
+
 void OMPClauseReader::VisitOMPPrivateClause(OMPPrivateClause *C) {
   C->setLParenLoc(Record.readSourceLocation());
   unsigned NumVars = C->varlist_size();
   SmallVector<Expr *, 16> Vars;
   Vars.reserve(NumVars);
   for (unsigned i = 0; i != NumVars; ++i)
     Vars.push_back(Record.readSubExpr());
   C->setVarRefs(Vars);

clang/lib/Serialization/ASTWriter.cpp

 }
 
 void OMPClauseWriter::VisitOMPSeverityClause(OMPSeverityClause *C) {
   Record.push_back(C->getSeverityKind());
   Record.AddSourceLocation(C->getLParenLoc());
   Record.AddSourceLocation(C->getSeverityKindKwLoc());
 }
 
+void OMPClauseWriter::VisitOMPMessageClause(OMPMessageClause *C) {
+  Record.AddStmt(C->getMessageString());
+  Record.AddSourceLocation(C->getLParenLoc());
+}
+
 void OMPClauseWriter::VisitOMPNontemporalClause(OMPNontemporalClause *C) {
   Record.push_back(C->varlist_size());
   Record.AddSourceLocation(C->getLParenLoc());
   for (auto *VE : C->varlists())
     Record.AddStmt(VE);
   for (auto *E : C->private_refs())
     Record.AddStmt(E);
 }

clang/test/OpenMP/error_ast_print.cpp

 // RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -ast-print %s | FileCheck %s
 // RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -fopenmp-version=51 -emit-pch -o %t %s
 // RUN: %clang_cc1 -fopenmp -std=c++11 -fopenmp-version=51 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
 
 // RUN: %clang_cc1 -verify -fopenmp-simd -fopenmp-version=51 -ast-print %s | FileCheck %s
 // RUN: %clang_cc1 -fopenmp-simd -x c++ -std=c++11 -fopenmp-version=51 -emit-pch -o %t %s
 // RUN: %clang_cc1 -fopenmp-simd -std=c++11 -fopenmp-version=51 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
 // expected-no-diagnostics
 
 #ifndef HEADER
 #define HEADER
 
 void foo() {}
 // CHECK: template <typename T, int N> int tmain(T argc, char **argv)
 // CHECK: static int a;
-// CHECK-NEXT: #pragma omp error at(execution) severity(fatal)
+// CHECK-NEXT: #pragma omp error at(execution) severity(fatal) message("GNU compiler required.")
 // CHECK-NEXT: a = argv[0][0];
 // CHECK-NEXT: ++a;
-// CHECK-NEXT: #pragma omp error at(execution) severity(warning)
+// CHECK-NEXT: #pragma omp error at(execution) severity(warning) message("Notice: add for loop.")
 // CHECK-NEXT: {
 // CHECK-NEXT: int b = 10;
 // CHECK-NEXT: T c = 100;
 // CHECK-NEXT: a = b + c;
 // CHECK-NEXT: }
-// CHECK-NEXT: #pragma omp error at(execution) severity(fatal)
+// CHECK-NEXT: #pragma omp error at(execution) severity(fatal) message("GPU compiler required.")
 // CHECK-NEXT: foo();
 // CHECK-NEXT: return N;
 
 template <typename T, int N>
 int tmain(T argc, char **argv) {
   T b = argc, c, d, e, f, g;
   static int a;
-#pragma omp error at(execution) severity(fatal)
+#pragma omp error at(execution) severity(fatal) message("GNU compiler required.")
   a = argv[0][0];
   ++a;
-#pragma omp error at(execution) severity(warning)
+#pragma omp error at(execution) severity(warning) message("Notice: add for loop.")
   {
     int b = 10;
     T c = 100;
     a = b + c;
   }
-#pragma omp  error at(execution) severity(fatal)
+#pragma omp  error at(execution) severity(fatal) message("GPU compiler required.")
   foo();
 return N;
 }
 
 // CHECK: int main(int argc, char **argv)
 // CHECK-NEXT: int b = argc, c, d, e, f, g;
 // CHECK-NEXT: static int a;
-// CHECK-NEXT: #pragma omp error at(execution) severity(fatal)
+// CHECK-NEXT: #pragma omp error at(execution) severity(fatal) message("GPU compiler required.")
 // CHECK-NEXT: a = 2;
-// CHECK-NEXT: #pragma omp error at(execution) severity(warning)
+// CHECK-NEXT: #pragma omp error at(execution) severity(warning) message("Note this is functioncall.")
 // CHECK-NEXT: foo();
 int main (int argc, char **argv) {
   int b = argc, c, d, e, f, g;
   static int a;
-#pragma omp error at(execution) severity(fatal)
+#pragma omp error at(execution) severity(fatal) message("GPU compiler required.")
    a=2;
-#pragma omp error at(execution) severity(warning)
+#pragma omp error at(execution) severity(warning) message("Note this is functioncall.")
   foo();
 }
 #endif

clang/test/OpenMP/error_message.cpp

 #pragma omp error severity(warning) // expected-warning {{WARNING}}
 #pragma omp error severity(fatal) // expected-error {{ERROR}}
 
 // expected-warning@+1 {{WARNING}}
 #pragma omp error at(compilation) severity(warning) // expected-warning {{WARNING}}
 #pragma omp error at(execution) severity(warning) // no error, diagnosic at runtime
 #pragma omp error at(compilation) severity(fatal) // expected-error {{ERROR}}
 #pragma omp error at(execution) severity(fatal) // no error, error at runtime
+
+#pragma omp error message("GPU compiler is needed.") // expected-error {{GPU compiler is needed}}
+#pragma omp error at(compilation) message("GPU compiler is needed.") // expected-error {{GPU compiler is needed}}
+#pragma omp error at(execution) message("GPU compiler is needed.") // no error
+// expected-warning@+1 {{GPU compiler is needed.}}
+#pragma omp error severity(warning) message("GPU compiler is needed.") // expected-warning {{GPU compiler is needed.}}
+#pragma omp error severity(fatal) message("GPU compiler is needed.") // expected-error {{GPU compiler is needed}}
+// expected-warning@+1 {{GPU compiler is needed.}}
+#pragma omp error at(compilation) severity(warning) message("GPU compiler is needed.") // expected-warning {{GPU compiler is needed.}}
+#pragma omp error at(compilation) severity(fatal) message("GPU compiler is needed.") // expected-error {{GPU compiler is needed.}}
+#pragma omp error at(execution) severity(warning) message("GPU compiler is needed.") // no warning warning will emit at runtime.
+#pragma omp error at(execution) severity(fatal) message("GPU compiler is needed.") // no warning warning will emit at runtime.
+
+// expected-error@+1 {{GPU compiler is needed.}}
+#pragma omp error message("GPU compiler is needed.") message("GPU compiler is needed.") // expected-error {{directive '#pragma omp error' cannot contain more than one 'message' clause}}
+  int a;
+// expected-warning@+1 {{expected string literal in 'clause message' - ignoring}}
+#pragma omp error message(a) // expected-error {{ERROR}}
+// expected-error@+1 {{ERROR}}
+#pragma omp error message() // expected-error {{expected expression}}
   return T();
 }
 
 #pragma omp error at(execution) // expected-error {{unexpected 'execution' modifier in non-executable context}}
 
 #pragma omp error at(compilation) // expected-error {{ERROR}}
 class A {
 

clang/tools/libclang/CIndex.cpp

 
 void OMPClauseEnqueue::VisitOMPAtomicDefaultMemOrderClause(
     const OMPAtomicDefaultMemOrderClause *) {}
 
 void OMPClauseEnqueue::VisitOMPAtClause(const OMPAtClause *) {}
 
 void OMPClauseEnqueue::VisitOMPSeverityClause(const OMPSeverityClause *) {}
 
+void OMPClauseEnqueue::VisitOMPMessageClause(const OMPMessageClause *) {}
+
 void OMPClauseEnqueue::VisitOMPDeviceClause(const OMPDeviceClause *C) {
   Visitor->AddStmt(C->getDevice());
 }
 
 void OMPClauseEnqueue::VisitOMPNumTeamsClause(const OMPNumTeamsClause *C) {
   VisitOMPClauseWithPreInit(C);
   Visitor->AddStmt(C->getNumTeams());
 }

flang/lib/Semantics/check-omp-structure.cpp

 CHECK_SIMPLE_CLAUSE(UseDeviceAddr, OMPC_use_device_addr)
 CHECK_SIMPLE_CLAUSE(Write, OMPC_write)
 CHECK_SIMPLE_CLAUSE(Init, OMPC_init)
 CHECK_SIMPLE_CLAUSE(Use, OMPC_use)
 CHECK_SIMPLE_CLAUSE(Novariants, OMPC_novariants)
 CHECK_SIMPLE_CLAUSE(Nocontext, OMPC_nocontext)
 CHECK_SIMPLE_CLAUSE(At, OMPC_at)
 CHECK_SIMPLE_CLAUSE(Severity, OMPC_severity)
+CHECK_SIMPLE_CLAUSE(Message, OMPC_message)
 CHECK_SIMPLE_CLAUSE(Filter, OMPC_filter)
 CHECK_SIMPLE_CLAUSE(When, OMPC_when)
 CHECK_SIMPLE_CLAUSE(AdjustArgs, OMPC_adjust_args)
 CHECK_SIMPLE_CLAUSE(AppendArgs, OMPC_append_args)
 CHECK_SIMPLE_CLAUSE(MemoryOrder, OMPC_memory_order)
 CHECK_SIMPLE_CLAUSE(Bind, OMPC_bind)
 CHECK_SIMPLE_CLAUSE(Align, OMPC_align)
 CHECK_SIMPLE_CLAUSE(Compare, OMPC_compare)

llvm/include/llvm/Frontend/OpenMP/OMP.td

def OMPC_AtomicDefaultMemOrder : Clause<"atomic_default_mem_order"> {
   let flangClass = "OmpAtomicDefaultMemOrderClause";
 }
 def OMPC_At : Clause<"at"> {
   let clangClass = "OMPAtClause";
 }
 def OMPC_Severity : Clause<"severity"> {
   let clangClass = "OMPSeverityClause";
 }
+def OMPC_Message : Clause<"message"> {
+  let clangClass = "OMPMessageClause";
+}
 def OMPC_Allocate : Clause<"allocate"> {
   let clangClass = "OMPAllocateClause";
   let flangClass = "OmpAllocateClause";
 }
 def OMPC_NonTemporal : Clause<"nontemporal"> {
   let clangClass = "OMPNontemporalClause";
   let flangClass = "Name";
   let isValueList = true;
let allowedClauses = [
     VersionedClause<OMPC_Hint>
   ];
 }
 def OMP_TaskYield : Directive<"taskyield"> {}
 def OMP_Barrier : Directive<"barrier"> {}
 def OMP_Error : Directive<"error"> {
   let allowedClauses = [
     VersionedClause<OMPC_At, 51>,
-    VersionedClause<OMPC_Severity, 51>
+    VersionedClause<OMPC_Severity, 51>,
+    VersionedClause<OMPC_Message, 51>
   ];
 }
 def OMP_TaskWait : Directive<"taskwait"> {
   let allowedClauses = [
     VersionedClause<OMPC_Depend, 50>
   ];
 }
 def OMP_TaskGroup : Directive<"taskgroup"> {