[OPENMP] Parsing and Sema support for 'omp declare target' directive

[DmitryPolukhin]

Summary

Add parsing, sema analysis for 'declare target' construct for OpenMP 4.0
(4.5 support will be added in separate patch).

The declare target directive specifies that variables, functions (C, C++
and Fortran), and subroutines (Fortran) are mapped to a device. The declare
target directive is a declarative directive. In Clang declare target is
implemented as implicit attribute for the declaration.

The syntax of the declare target directive is as follows:

#pragma omp declare target
declarations-definition-seq
#pragma omp end declare target

Based on patch from Michael Wong http://reviews.llvm.org/D15321

[DmitryPolukhin]

• Added test for templates in declare target region

[DmitryPolukhin]

Aaron,

Could you please take a look to OMPDeclareTargetDecl attribute implementation and printPrettyEnd approach in general?
For post print mechanism alternative approach is to use ad hoc solution in DeclPrinter.

Thanks,
Dmitry

Software Engineer
Intel Compiler Team

[aaron.ballman]

In D18542#387934, @DmitryPolukhin wrote:

Could you please take a look to OMPDeclareTargetDecl attribute implementation and printPrettyEnd approach in general?
For post print mechanism alternative approach is to use ad hoc solution in DeclPrinter.

Attributes are meant to be wholly-contained entities syntactically, so I'm not entirely comfortable with the notion of an attribute having an "ending" because that breaks the model. However, pragmas and statement-level attributes are examples of attribute constructs that sometimes want to be paired together, so I see utility in the overall idea. I sort of feel like what we need is the notion of grouping related attributes together (we already need this for mutual exclusion of attributes, but I see no reason why it couldn't also cover mutual inclusion). Then pretty printing has a natural place for "end" logic within this declarative container.

If you don't feel like doing all that design work (which I'm not attempting to sign you up for!), I think the ad hoc solution may be preferable to the proposed approach. Do you intend to add several more pragmas that need this same sort of behavior, or is this a one-off?

include/clang/Basic/Attr.td

2250

It's a bit odd to say it has no spellings and then give it a spelling list. ;-)

[DmitryPolukhin]

• implemented ad hoc solution for printing
• added documentation for the attrbute
• reabse

In D18542#388241, @aaron.ballman wrote:

If you don't feel like doing all that design work (which I'm not attempting to sign you up for!), I think the ad hoc solution may be preferable to the proposed approach. Do you intend to add several more pragmas that need this same sort of behavior, or is this a one-off?

I don't expect more pragmas like declare target and grouping mechanism design might be overkill for my case. So I implemented ad hoc solution that is much shorter. PTAL!

[DmitryPolukhin]

Alexey, please review OpenMP specific things.

Aaron, are you OK with the attribute implementation and printing approach?

[ABataev]

LG

[aaron.ballman]

Just some very minor nits, otherwise LGTM!

include/clang/Basic/DiagnosticSemaKinds.td

7922

s/into/within

include/clang/Sema/Sema.h

7923

This method should be marked const.

lib/Frontend/MultiplexConsumer.cpp

225

Use std::for_each (or at least a range-based for loop) over Listeners.

lib/Sema/SemaOpenMP.cpp

10405

Please do not use auto since the type is not spelled anywhere else in the expression.

10420

Please do not use auto since the type is not spelled anywhere else in the expression.

10450

Please do not use auto since the type is not spelled anywhere else in the expression.

10486

Please do not use auto since the type is not spelled anywhere else in the expression.

10497

Please do not use auto since the type is not spelled anywhere else in the expression.

[DmitryPolukhin]

• fixed all comments
• rebase

Aaron and Alexey, thank you for the review!

[DmitryPolukhin]

Committed as rL265530

include/clang/AST/ASTMutationListener.h

public:
   virtual void DeclarationMarkedUsed(const Decl *D) {}
 
   /// \brief A declaration is marked as OpenMP threadprivate which was not
   /// previously marked as threadprivate.
   ///
   /// \param D the declaration marked OpenMP threadprivate.
   virtual void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {}
 
+  /// \brief A declaration is marked as OpenMP declaretarget which was not
+  /// previously marked as declaretarget.
+  ///
+  /// \param D the declaration marked OpenMP declaretarget.
+  virtual void DeclarationMarkedOpenMPDeclareTarget(const Decl *D) {}
+
   /// \brief A definition has been made visible by being redefined locally.
   ///
   /// \param D The definition that was previously not visible.
   /// \param M The containing module in which the definition was made visible,
   ///        if any.
   virtual void RedefinedHiddenDefinition(const NamedDecl *D, Module *M) {}
   
   /// \brief An attribute was added to a RecordDecl

include/clang/AST/Attr.h

public:
   // Clone this attribute.
   Attr *clone(ASTContext &C) const;
 
   bool isLateParsed() const { return IsLateParsed; }
 
   // Pretty print this attribute.
   void printPretty(raw_ostream &OS, const PrintingPolicy &Policy) const;
 
+  // Pretty print this attribute ending text if any.
+  void printPrettyEnd(raw_ostream &OS, const PrintingPolicy &Policy) const;
+
   /// \brief By default, attributes cannot be duplicated when being merged;
   /// however, an attribute can override this. Returns true if the attribute
   /// can be duplicated when merging.
   bool duplicatesAllowed() const { return DuplicatesAllowed; }
 };
 
 class StmtAttr : public Attr {
 protected:

include/clang/Basic/Attr.td

 class GNU<string name> : Spelling<name, "GNU">;
 class Declspec<string name> : Spelling<name, "Declspec">;
 class CXX11<string namespace, string name, int version = 1>
     : Spelling<name, "CXX11"> {
   string Namespace = namespace;
   int Version = version;
 }
 class Keyword<string name> : Spelling<name, "Keyword">;
-class Pragma<string namespace, string name> : Spelling<name, "Pragma"> {
+class Pragma<string namespace, string name, string ending = "">
+    : Spelling<name, "Pragma"> {
   string Namespace = namespace;
+  string Ending = ending;
 }
 
 // The GCC spelling implies GNU<name, "GNU"> and CXX11<"gnu", name> and also
 // sets KnownToGCC to 1. This spelling should be used for any GCC-compatible
 // attributes.
 class GCC<string name> : Spelling<name, "GCC"> {
   let KnownToGCC = 1;
 }

 
 def OMPCaptureNoInit : InheritableAttr {
   // This attribute has no spellings as it is only ever created implicitly.
   let Spellings = [];
   let SemaHandler = 0;
   let Documentation = [Undocumented];
 }
 
+def OMPDeclareTargetDecl : Attr {
+  // This attribute has no spellings as it is only ever created implicitly.
+  let Spellings = [Pragma<"omp", "declare target", "end declare target">];
+  let SemaHandler = 0;
+  let Documentation = [Undocumented];
+  let AdditionalMembers = [{
+    void printPrettyPragma(raw_ostream &OS, const PrintingPolicy &Policy) const {}
+  }];
+}
+
 def InternalLinkage : InheritableAttr {
   let Spellings = [GNU<"internal_linkage">, CXX11<"clang", "internal_linkage">];
   let Subjects = SubjectList<[Var, Function, CXXRecord]>;
   let Documentation = [InternalLinkageDocs];
 }

include/clang/Basic/DiagnosticGroups.td

 def ASM : DiagGroup<"asm", [
     ASMOperandWidths
   ]>;
 
 // OpenMP warnings.
 def SourceUsesOpenMP : DiagGroup<"source-uses-openmp">;
 def OpenMPClauses : DiagGroup<"openmp-clauses">;
 def OpenMPLoopForm : DiagGroup<"openmp-loop-form">;
+def OpenMPTarget : DiagGroup<"openmp-target">;
 
 // Backend warnings.
 def BackendInlineAsm : DiagGroup<"inline-asm">;
 def BackendFrameLargerThanEQ : DiagGroup<"frame-larger-than=">;
 def BackendPlugin : DiagGroup<"backend-plugin">;
 def RemarkBackendPlugin : DiagGroup<"remark-backend-plugin">;
 def BackendOptimizationRemark : DiagGroup<"pass">;
 def BackendOptimizationRemarkMissed : DiagGroup<"pass-missed">;

include/clang/Basic/DiagnosticParseKinds.td

 def err_omp_expected_reduction_identifier : Error<
   "expected identifier or one of the following operators: '+', '-', '*', '&', '|', '^', '&&', or '||'">;
 def err_omp_unknown_map_type : Error<
   "incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'">;
 def err_omp_unknown_map_type_modifier : Error<
   "incorrect map type modifier, expected 'always'">;
 def err_omp_map_type_missing : Error<
   "missing map type">;
+def err_expected_end_declare_target : Error<
+  "expected '#pragma omp end declare target'">;
 
 // Pragma loop support.
 def err_pragma_loop_missing_argument : Error<
   "missing argument; expected %select{an integer value|"
   "'enable', %select{'assume_safety'|'full'}1 or 'disable'}0">;
 def err_pragma_loop_invalid_option : Error<
   "%select{invalid|missing}0 option%select{ %1|}0; expected vectorize, "
   "vectorize_width, interleave, interleave_count, unroll, or unroll_count">;

include/clang/Basic/DiagnosticSemaKinds.td

def err_omp_expected_var_arg : Error<
   "%0 is not a global variable, static local variable or static data member">;
 def err_omp_expected_var_arg_suggest : Error<
   "%0 is not a global variable, static local variable or static data member; "
   "did you mean %1">;
 def err_omp_global_var_arg : Error<
   "arguments of '#pragma omp %0' must have %select{global storage|static storage duration}1">;
 def err_omp_ref_type_arg : Error<
   "arguments of '#pragma omp %0' cannot be of reference type %1">;
+def err_omp_region_not_file_context : Error<
+  "directive must be at file or namespace scope">;
 def err_omp_var_scope : Error<
   "'#pragma omp %0' must appear in the scope of the %q1 variable declaration">;
 def err_omp_var_used : Error<
   "'#pragma omp %0' must precede all references to variable %q1">;
 def err_omp_var_thread_local : Error<
   "variable %0 cannot be threadprivate because it is %select{thread-local|a global named register variable}1">;
 def err_omp_private_incomplete_type : Error<
   "a private variable with incomplete type %0">;
def err_omp_not_for : Error<
   "expected %2 for loops after '#pragma omp %1'%select{|, but found only %4}3}0">;
 def note_omp_collapse_ordered_expr : Note<
   "as specified in %select{'collapse'|'ordered'|'collapse' and 'ordered'}0 clause%select{||s}0">;
 def err_omp_negative_expression_in_clause : Error<
   "argument to '%0' clause must be a %select{non-negative|strictly positive}1 integer value">;
 def err_omp_not_integral : Error<
   "expression must have integral or unscoped enumeration "
   "type, not %0">;
+def err_omp_threadprivate_in_target : Error<
+  "threadprivate variables cannot be used in target constructs">;
 def err_omp_incomplete_type : Error<
   "expression has incomplete class type %0">;
 def err_omp_explicit_conversion : Error<
   "expression requires explicit conversion from %0 to %1">;
 def note_omp_conversion_here : Note<
   "conversion to %select{integral|enumeration}0 type %1 declared here">;
 def err_omp_ambiguous_conversion : Error<
   "ambiguous conversion from type %0 to an integral or unscoped "
def err_omp_linear_expected_int_or_ptr : Error<
   "argument of a linear clause should be of integral or pointer "
   "type, not %0">;
 def warn_omp_linear_step_zero : Warning<
   "zero linear step (%0 %select{|and other variables in clause }1should probably be const)">,
   InGroup<OpenMPClauses>;
 def warn_omp_alignment_not_power_of_two : Warning<
   "aligned clause will be ignored because the requested alignment is not a power of 2">,
   InGroup<OpenMPClauses>;
+def err_omp_enclosed_declare_target : Error<
+  "declare target region may not be enclosed into another declare target region">;
+def warn_omp_not_in_target_context : Warning<
+  "declaration is not declared in any declare target region">,
+  InGroup<OpenMPTarget>;
 def err_omp_aligned_expected_array_or_ptr : Error<
   "argument of aligned clause should be array"
   "%select{ or pointer|, pointer, reference to array or reference to pointer}1"
   ", not %0">;
 def err_omp_aligned_twice : Error<
   "a variable cannot appear in more than one aligned clause">;
 def err_omp_local_var_in_threadprivate_init : Error<
   "variable with local storage in initial value of threadprivate variable">;

include/clang/Basic/OpenMPKinds.def

 OPENMP_DIRECTIVE_EXT(parallel_for_simd, "parallel for simd")
 OPENMP_DIRECTIVE_EXT(parallel_sections, "parallel sections")
 OPENMP_DIRECTIVE_EXT(for_simd, "for simd")
 OPENMP_DIRECTIVE_EXT(cancellation_point, "cancellation point")
 OPENMP_DIRECTIVE_EXT(declare_reduction, "declare reduction")
 OPENMP_DIRECTIVE(taskloop)
 OPENMP_DIRECTIVE_EXT(taskloop_simd, "taskloop simd")
 OPENMP_DIRECTIVE(distribute)
+OPENMP_DIRECTIVE_EXT(declare_target, "declare target")
+OPENMP_DIRECTIVE_EXT(end_declare_target, "end declare target")
 
 // OpenMP clauses.
 OPENMP_CLAUSE(if, OMPIfClause)
 OPENMP_CLAUSE(final, OMPFinalClause)
 OPENMP_CLAUSE(num_threads, OMPNumThreadsClause)
 OPENMP_CLAUSE(safelen, OMPSafelenClause)
 OPENMP_CLAUSE(simdlen, OMPSimdlenClause)
 OPENMP_CLAUSE(collapse, OMPCollapseClause)

include/clang/Sema/Sema.h

 
   void CheckCompletedCoroutineBody(FunctionDecl *FD, Stmt *&Body);
 
   //===--------------------------------------------------------------------===//
   // OpenMP directives and clauses.
   //
 private:
   void *VarDataSharingAttributesStack;
+  /// Set to true inside '#pragma omp declare target' region.
+  bool IsInOpenMPDeclareTargetContext = false;
   /// \brief Initialization of data-sharing attributes stack.
   void InitDataSharingAttributesStack();
   void DestroyDataSharingAttributesStack();
   ExprResult
   VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
                                         bool StrictlyPositive = true);
 
 public:
public:
   /// \brief Initialize declare reduction construct initializer.
   void ActOnOpenMPDeclareReductionInitializerStart(Scope *S, Decl *D);
   /// \brief Finish current declare reduction construct initializer.
   void ActOnOpenMPDeclareReductionInitializerEnd(Decl *D, Expr *Initializer);
   /// \brief Called at the end of '#pragma omp declare reduction'.
   DeclGroupPtrTy ActOnOpenMPDeclareReductionDirectiveEnd(
       Scope *S, DeclGroupPtrTy DeclReductions, bool IsValid);
 
+  /// Called on the start of target region i.e. '#pragma omp declare target'.
+  bool ActOnStartOpenMPDeclareTargetDirective(SourceLocation Loc);
+  /// Called at the end of target region i.e. '#pragme omp end declare target'.
+  void ActOnFinishOpenMPDeclareTargetDirective();
+  /// Check declaration inside target region.
+  void checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D);
+  /// Return true inside OpenMP target region.
+  bool isInOpenMPDeclareTargetContext() {
+    return IsInOpenMPDeclareTargetContext;
+  }
+
   /// \brief Initialization of captured region for OpenMP region.
   void ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope);
   /// \brief End of OpenMP region.
   ///
   /// \param S Statement associated with the current OpenMP region.
   /// \param Clauses List of clauses for the current OpenMP region.
   ///
   /// \returns Statement for finished OpenMP region.

include/clang/Serialization/ASTWriter.h

public:
   void CompletedImplicitDefinition(const FunctionDecl *D) override;
   void StaticDataMemberInstantiated(const VarDecl *D) override;
   void DefaultArgumentInstantiated(const ParmVarDecl *D) override;
   void FunctionDefinitionInstantiated(const FunctionDecl *D) override;
   void AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
                                     const ObjCInterfaceDecl *IFD) override;
   void DeclarationMarkedUsed(const Decl *D) override;
   void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) override;
+  void DeclarationMarkedOpenMPDeclareTarget(const Decl *D) override;
   void RedefinedHiddenDefinition(const NamedDecl *D, Module *M) override;
   void AddedAttributeToRecord(const Attr *Attr,
                               const RecordDecl *Record) override;
 };
 
 /// \brief AST and semantic-analysis consumer that generates a
 /// precompiled header from the parsed source code.
 class PCHGenerator : public SemaConsumer {

lib/AST/ASTContext.cpp

if (VD->getDescribedVarTemplate() ||
         isa<VarTemplatePartialSpecializationDecl>(VD))
       return false;
   } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
     // We never need to emit an uninstantiated function template.
     if (FD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
       return false;
   } else if (isa<PragmaCommentDecl>(D))
     return true;
+  else if (isa<OMPThreadPrivateDecl>(D) ||
+           D->hasAttr<OMPDeclareTargetDeclAttr>())
+    return true;
   else if (isa<PragmaDetectMismatchDecl>(D))
     return true;
   else if (isa<OMPThreadPrivateDecl>(D))
     return !D->getDeclContext()->isDependentContext();
   else if (isa<OMPDeclareReductionDecl>(D))
     return !D->getDeclContext()->isDependentContext();
   else
     return false;

lib/AST/DeclPrinter.cpp

public:
     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
 
     void PrintTemplateParameters(const TemplateParameterList *Params,
                                  const TemplateArgumentList *Args = nullptr);
     void prettyPrintAttributes(Decl *D);
     void prettyPrintPragmas(Decl *D);
+    void prettyPrintEndPragmas(Decl *D);
     void printDeclType(QualType T, StringRef DeclName, bool Pack = false);
   };
 }
 
 void Decl::print(raw_ostream &Out, unsigned Indentation,
                  bool PrintInstantiation) const {
   print(Out, getASTContext().getPrintingPolicy(), Indentation, PrintInstantiation);
 }
#include "clang/Basic/AttrList.inc"
         break;
       default:
         break;
       }
     }
   }
 }
 
+void DeclPrinter::prettyPrintEndPragmas(Decl *D) {
+  if (Policy.PolishForDeclaration)
+    return;
+
+  if (D->hasAttrs()) {
+    AttrVec &Attrs = D->getAttrs();
+    for (auto *A : Attrs) {
+      switch (A->getKind()) {
+#define ATTR(X)
+#define PRAGMA_SPELLING_ATTR(X) case attr::X:
+#include "clang/Basic/AttrList.inc"
+        A->printPrettyEnd(Out, Policy);
+        Indent();
+        break;
+      default:
+        break;
+      }
+    }
+  }
+}
+
 void DeclPrinter::printDeclType(QualType T, StringRef DeclName, bool Pack) {
   // Normally, a PackExpansionType is written as T[3]... (for instance, as a
   // template argument), but if it is the type of a declaration, the ellipsis
   // is placed before the name being declared.
   if (auto *PET = T->getAs<PackExpansionType>()) {
     Pack = true;
     T = PET->getPattern();
   }
else if (isa<EnumConstantDecl>(*D)) {
       if (Next != DEnd)
         Terminator = ",";
     } else
       Terminator = ";";
 
     if (Terminator)
       Out << Terminator;
     Out << "\n";
+
+    prettyPrintEndPragmas(*D);
   }
 
   if (!Decls.empty())
     ProcessDeclGroup(Decls);
 
   if (Indent)
     Indentation -= Policy.Indentation;
 }

lib/Basic/OpenMPKinds.cpp

 #define OPENMP_DISTRIBUTE_CLAUSE(Name)                                         \
   case OMPC_##Name:                                                            \
     return true;
 #include "clang/Basic/OpenMPKinds.def"
     default:
       break;
     }
     break;
+  case OMPD_declare_target:
+  case OMPD_end_declare_target:
   case OMPD_unknown:
   case OMPD_threadprivate:
   case OMPD_section:
   case OMPD_master:
   case OMPD_taskyield:
   case OMPD_barrier:
   case OMPD_taskwait:
   case OMPD_taskgroup:

lib/Frontend/MultiplexConsumer.cpp

public:
   void CompletedImplicitDefinition(const FunctionDecl *D) override;
   void StaticDataMemberInstantiated(const VarDecl *D) override;
   void DefaultArgumentInstantiated(const ParmVarDecl *D) override;
   void AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
                                     const ObjCInterfaceDecl *IFD) override;
   void FunctionDefinitionInstantiated(const FunctionDecl *D) override;
   void DeclarationMarkedUsed(const Decl *D) override;
   void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) override;
+  void DeclarationMarkedOpenMPDeclareTarget(const Decl *D) override;
   void RedefinedHiddenDefinition(const NamedDecl *D, Module *M) override;
   void AddedAttributeToRecord(const Attr *Attr, 
                               const RecordDecl *Record) override;
 
 private:
   std::vector<ASTMutationListener*> Listeners;
 };
 
void MultiplexASTMutationListener::DeclarationMarkedUsed(const Decl *D) {
   for (size_t i = 0, e = Listeners.size(); i != e; ++i)
     Listeners[i]->DeclarationMarkedUsed(D);
 }
 void MultiplexASTMutationListener::DeclarationMarkedOpenMPThreadPrivate(
     const Decl *D) {
   for (size_t i = 0, e = Listeners.size(); i != e; ++i)
     Listeners[i]->DeclarationMarkedOpenMPThreadPrivate(D);
 }
+void MultiplexASTMutationListener::DeclarationMarkedOpenMPDeclareTarget(
+    const Decl *D) {
+  for (size_t i = 0, e = Listeners.size(); i != e; ++i)
+    Listeners[i]->DeclarationMarkedOpenMPDeclareTarget(D);
+}
 void MultiplexASTMutationListener::RedefinedHiddenDefinition(const NamedDecl *D,
                                                              Module *M) {
   for (auto *L : Listeners)
     L->RedefinedHiddenDefinition(D, M);
 }
   
 void MultiplexASTMutationListener::AddedAttributeToRecord(
                                                     const Attr *Attr, 

lib/Parse/ParseOpenMP.cpp

 // OpenMP declarative directives.
 //===----------------------------------------------------------------------===//
 
 namespace {
 enum OpenMPDirectiveKindEx {
   OMPD_cancellation = OMPD_unknown + 1,
   OMPD_data,
   OMPD_declare,
+  OMPD_end,
+  OMPD_end_declare,
   OMPD_enter,
   OMPD_exit,
   OMPD_point,
   OMPD_reduction,
   OMPD_target_enter,
   OMPD_target_exit
 };
 } // namespace
 
 // Map token string to extended OMP token kind that are
 // OpenMPDirectiveKind + OpenMPDirectiveKindEx.
 static unsigned getOpenMPDirectiveKindEx(StringRef S) {
   auto DKind = getOpenMPDirectiveKind(S);
   if (DKind != OMPD_unknown)
     return DKind;
 
   return llvm::StringSwitch<unsigned>(S)
       .Case("cancellation", OMPD_cancellation)
       .Case("data", OMPD_data)
       .Case("declare", OMPD_declare)
+      .Case("end", OMPD_end)
       .Case("enter", OMPD_enter)
       .Case("exit", OMPD_exit)
       .Case("point", OMPD_point)
       .Case("reduction", OMPD_reduction)
       .Default(OMPD_unknown);
 }
 
 static OpenMPDirectiveKind ParseOpenMPDirectiveKind(Parser &P) {
   // Array of foldings: F[i][0] F[i][1] ===> F[i][2].
   // E.g.: OMPD_for OMPD_simd ===> OMPD_for_simd
   // TODO: add other combined directives in topological order.
   static const unsigned F[][3] = {
     { OMPD_cancellation, OMPD_point, OMPD_cancellation_point },
     { OMPD_declare, OMPD_reduction, OMPD_declare_reduction },
+    { OMPD_declare, OMPD_target, OMPD_declare_target },
+    { OMPD_end, OMPD_declare, OMPD_end_declare },
+    { OMPD_end_declare, OMPD_target, OMPD_end_declare_target },
     { OMPD_target, OMPD_data, OMPD_target_data },
     { OMPD_target, OMPD_enter, OMPD_target_enter },
     { OMPD_target, OMPD_exit, OMPD_target_exit },
     { OMPD_target_enter, OMPD_data, OMPD_target_enter_data },
     { OMPD_target_exit, OMPD_data, OMPD_target_exit_data },
     { OMPD_for, OMPD_simd, OMPD_for_simd },
     { OMPD_parallel, OMPD_for, OMPD_parallel_for },
     { OMPD_parallel_for, OMPD_simd, OMPD_parallel_for_simd },
if (auto Res = ParseOpenMPDeclareReductionDirective(AS)) {
         while (Tok.isNot(tok::annot_pragma_openmp_end))
           ConsumeAnyToken();
       }
       // Skip the last annot_pragma_openmp_end.
       ConsumeToken();
       return Res;
     }
     break;
+  case OMPD_declare_target: {
+    SourceLocation DTLoc = ConsumeAnyToken();
+    if (Tok.isNot(tok::annot_pragma_openmp_end)) {
+      Diag(Tok, diag::warn_omp_extra_tokens_at_eol)
+          << getOpenMPDirectiveName(OMPD_declare_target);
+      SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
+    }
+    // Skip the last annot_pragma_openmp_end.
+    ConsumeAnyToken();
+
+    if (!Actions.ActOnStartOpenMPDeclareTargetDirective(DTLoc))
+      return DeclGroupPtrTy();
+
+    DKind = ParseOpenMPDirectiveKind(*this);
+    while (DKind != OMPD_end_declare_target && DKind != OMPD_declare_target &&
+           Tok.isNot(tok::eof) && Tok.isNot(tok::r_brace)) {
+      ParsedAttributesWithRange attrs(AttrFactory);
+      MaybeParseCXX11Attributes(attrs);
+      MaybeParseMicrosoftAttributes(attrs);
+      ParseExternalDeclaration(attrs);
+      if (Tok.isAnnotation() && Tok.is(tok::annot_pragma_openmp)) {
+        TentativeParsingAction TPA(*this);
+        ConsumeToken();
+        DKind = ParseOpenMPDirectiveKind(*this);
+        if (DKind != OMPD_end_declare_target)
+          TPA.Revert();
+        else
+          TPA.Commit();
+      }
+    }
+
+    if (DKind == OMPD_end_declare_target) {
+      ConsumeAnyToken();
+      if (Tok.isNot(tok::annot_pragma_openmp_end)) {
+        Diag(Tok, diag::warn_omp_extra_tokens_at_eol)
+            << getOpenMPDirectiveName(OMPD_end_declare_target);
+        SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
+      }
+      // Skip the last annot_pragma_openmp_end.
+      ConsumeAnyToken();
+    } else {
+      Diag(Tok, diag::err_expected_end_declare_target);
+      Diag(DTLoc, diag::note_matching) << "'#pragma omp declare target'";
+    }
+    Actions.ActOnFinishOpenMPDeclareTargetDirective();
+    return DeclGroupPtrTy();
+  }
   case OMPD_unknown:
     Diag(Tok, diag::err_omp_unknown_directive);
     break;
   case OMPD_parallel:
   case OMPD_simd:
   case OMPD_task:
   case OMPD_taskyield:
   case OMPD_barrier:
Parser::ParseOpenMPDeclarativeDirective(AccessSpecifier AS) {
   case OMPD_target_data:
   case OMPD_target_enter_data:
   case OMPD_target_exit_data:
   case OMPD_target_parallel:
   case OMPD_target_parallel_for:
   case OMPD_taskloop:
   case OMPD_taskloop_simd:
   case OMPD_distribute:
+  case OMPD_end_declare_target:
     Diag(Tok, diag::err_omp_unexpected_directive)
         << getOpenMPDirectiveName(DKind);
     break;
   }
   while (Tok.isNot(tok::annot_pragma_openmp_end))
     ConsumeAnyToken();
   ConsumeAnyToken();
   return nullptr;
Directive = Actions.ActOnOpenMPExecutableDirective(
         DKind, DirName, CancelRegion, Clauses, AssociatedStmt.get(), Loc,
         EndLoc);
 
     // Exit scope.
     Actions.EndOpenMPDSABlock(Directive.get());
     OMPDirectiveScope.Exit();
     break;
   }
+  case OMPD_declare_target:
+  case OMPD_end_declare_target:
+    Diag(Tok, diag::err_omp_unexpected_directive)
+        << getOpenMPDirectiveName(DKind);
+    SkipUntil(tok::annot_pragma_openmp_end);
+    break;
   case OMPD_unknown:
     Diag(Tok, diag::err_omp_unknown_directive);
     SkipUntil(tok::annot_pragma_openmp_end);
     break;
   }
   return Directive;
 }
 

lib/Sema/SemaDecl.cpp

if (New->getDeclName() && AddToScope &&
     // declaration of this entity. Qualified lookup for such an entity should
     // only find this declaration if there is no visible declaration of it.
     bool AddToContext = !D.isRedeclaration() || !New->isLocalExternDecl();
     PushOnScopeChains(New, S, AddToContext);
     if (!AddToContext)
       CurContext->addHiddenDecl(New);
   }
 
+  if (isInOpenMPDeclareTargetContext())
+    checkDeclIsAllowedInOpenMPTarget(nullptr, New);
+
   return New;
 }
 
 /// Helper method to turn variable array types into constant array
 /// types in certain situations which would otherwise be errors (for
 /// GCC compatibility).
 static QualType TryToFixInvalidVariablyModifiedType(QualType T,
                                                     ASTContext &Context,

lib/Sema/SemaExpr.cpp

 /// (C++ [basic.def.odr]p2, C99 6.9p3).  Note that this should not be
 /// used directly for normal expressions referring to VarDecl.
 void Sema::MarkVariableReferenced(SourceLocation Loc, VarDecl *Var) {
   DoMarkVarDeclReferenced(*this, Loc, Var, nullptr);
 }
 
 static void MarkExprReferenced(Sema &SemaRef, SourceLocation Loc,
                                Decl *D, Expr *E, bool MightBeOdrUse) {
+  if (SemaRef.isInOpenMPDeclareTargetContext())
+    SemaRef.checkDeclIsAllowedInOpenMPTarget(E, D);
+
   if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
     DoMarkVarDeclReferenced(SemaRef, Loc, Var, E);
     return;
   }
 
   SemaRef.MarkAnyDeclReferenced(Loc, D, MightBeOdrUse);
 
   // If this is a call to a method via a cast, also mark the method in the

lib/Sema/SemaOpenMP.cpp

void Sema::ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope) {
   case OMPD_barrier:
   case OMPD_taskwait:
   case OMPD_cancellation_point:
   case OMPD_cancel:
   case OMPD_flush:
   case OMPD_target_enter_data:
   case OMPD_target_exit_data:
   case OMPD_declare_reduction:
+  case OMPD_declare_target:
+  case OMPD_end_declare_target:
     llvm_unreachable("OpenMP Directive is not allowed");
   case OMPD_unknown:
     llvm_unreachable("Unknown OpenMP directive");
   }
 }
 
 static OMPCapturedExprDecl *buildCaptureDecl(Sema &S, IdentifierInfo *Id,
                                              Expr *CaptureExpr, bool WithInit) {
case OMPD_taskloop_simd:
     Res = ActOnOpenMPTaskLoopSimdDirective(ClausesWithImplicit, AStmt, StartLoc,
                                            EndLoc, VarsWithInheritedDSA);
     AllowedNameModifiers.push_back(OMPD_taskloop);
     break;
   case OMPD_distribute:
     Res = ActOnOpenMPDistributeDirective(ClausesWithImplicit, AStmt, StartLoc,
                                          EndLoc, VarsWithInheritedDSA);
     break;
+  case OMPD_declare_target:
+  case OMPD_end_declare_target:
   case OMPD_threadprivate:
   case OMPD_declare_reduction:
     llvm_unreachable("OpenMP Directive is not allowed");
   case OMPD_unknown:
     llvm_unreachable("Unknown OpenMP directive");
   }
 
   for (auto P : VarsWithInheritedDSA) {
if (M != OMPC_DEFAULTMAP_MODIFIER_tofrom ||
     Diag(Loc, diag::err_omp_unexpected_clause_value)
         << Value << getOpenMPClauseName(OMPC_defaultmap);
     return nullptr;
   }
 
   return new (Context)
       OMPDefaultmapClause(StartLoc, LParenLoc, MLoc, KindLoc, EndLoc, Kind, M);
 }
+
+bool Sema::ActOnStartOpenMPDeclareTargetDirective(SourceLocation Loc) {
+  DeclContext *CurLexicalContext = getCurLexicalContext();
+  if (!CurLexicalContext->isFileContext() &&
+      !CurLexicalContext->isExternCContext() &&
+      !CurLexicalContext->isExternCXXContext()) {
+    Diag(Loc, diag::err_omp_region_not_file_context);
+    return false;
+  }
+  if (IsInOpenMPDeclareTargetContext) {
+    Diag(Loc, diag::err_omp_enclosed_declare_target);
+    return false;
+  }
+
+  IsInOpenMPDeclareTargetContext = true;
+  return true;
+}
+
+void Sema::ActOnFinishOpenMPDeclareTargetDirective() {
+  assert(IsInOpenMPDeclareTargetContext &&
+         "Unexpected ActOnFinishOpenMPDeclareTargetDirective");
+
+  IsInOpenMPDeclareTargetContext = false;
+}
+
+static void checkDeclInTargetContext(SourceLocation SL, SourceRange SR,
+                                     Sema &SemaRef, Decl *D) {
+  if (!D)
+    return;
+  Decl *LD = nullptr;
+  if (isa<TagDecl>(D)) {
+    LD = cast<TagDecl>(D)->getDefinition();
+  } else if (isa<VarDecl>(D)) {
+    LD = cast<VarDecl>(D)->getDefinition();
+
+    // If this is an implicit variable that is legal and we do not need to do
+    // anything.
+    if (cast<VarDecl>(D)->isImplicit()) {
+      D->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(SemaRef.Context));
+      if (auto *ML = SemaRef.Context.getASTMutationListener())
+        ML->DeclarationMarkedOpenMPDeclareTarget(D);
+      return;
+    }
+
+  } else if (isa<FunctionDecl>(D)) {
+    const FunctionDecl *FD = nullptr;
+    if (cast<FunctionDecl>(D)->hasBody(FD))
+      LD = const_cast<FunctionDecl *>(FD);
+
+    // If the definition is associated with the current declaration in the
+    // target region (it can be e.g. a lambda) that is legal and we do not need
+    // to do anything else.
+    if (LD == D) {
+      D->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(SemaRef.Context));
+      if (auto *ML = SemaRef.Context.getASTMutationListener())
+        ML->DeclarationMarkedOpenMPDeclareTarget(D);
+      return;
+    }
+  }
+  if (!LD)
+    LD = D;
+  if (LD) {
+    if (!LD->hasAttr<OMPDeclareTargetDeclAttr>()) {
+      // Outlined declaration is not declared target.
+      if (LD->isOutOfLine()) {
+        SemaRef.Diag(LD->getLocation(), diag::warn_omp_not_in_target_context);
+        SemaRef.Diag(SL, diag::note_used_here) << SR;
+      } else {
+        DeclContext *DC = LD->getDeclContext();
+        while (DC) {
+          if (isa<FunctionDecl>(DC) &&
+              cast<FunctionDecl>(DC)->hasAttr<OMPDeclareTargetDeclAttr>())
+            break;
+          DC = DC->getParent();
+        }
+        // Is not declared in target context.
+        if (!DC) {
+          SemaRef.Diag(LD->getLocation(), diag::warn_omp_not_in_target_context);
+          SemaRef.Diag(SL, diag::note_used_here) << SR;
+        }
+      }
+    }
+    // Mark decl as declared target to prevent further diagnostic.
+    if (isa<VarDecl>(LD) || isa<FunctionDecl>(LD)) {
+      D->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(SemaRef.Context));
+      if (auto *ML = SemaRef.Context.getASTMutationListener())
+        ML->DeclarationMarkedOpenMPDeclareTarget(D);
+    }
+  }
+}
+
+static bool checkValueDeclInTarget(SourceLocation SL, SourceRange SR,
+                                   Sema &SemaRef, DSAStackTy *Stack,
+                                   ValueDecl *VD) {
+  if (VD->hasAttr<OMPDeclareTargetDeclAttr>())
+    return true;
+  if (!CheckTypeMappable(SL, SR, SemaRef, Stack, VD->getType()))
+    return false;
+  return true;
+}
+
+void Sema::checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D) {
+  if (!D || D->isInvalidDecl())
+    return;
+  SourceRange SR = E ? E->getSourceRange() : D->getSourceRange();
+  SourceLocation SL = E ? E->getLocStart() : D->getLocation();
+  // 2.10.6: threadprivate variable cannot appear in a declare target directive.
+  if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
+    if (DSAStack->isThreadPrivate(VD)) {
+      Diag(SL, diag::err_omp_threadprivate_in_target);
+      ReportOriginalDSA(*this, DSAStack, VD, DSAStack->getTopDSA(VD, false));
+      return;
+    }
+  }
+  if (ValueDecl *VD = dyn_cast<ValueDecl>(D)) {
+    if (!checkValueDeclInTarget(SL, SR, *this, DSAStack, VD)) {
+      // Mark decl as declared target to prevent further diagnostic.
+      if (isa<VarDecl>(VD) || isa<FunctionDecl>(VD)) {
+        VD->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(Context));
+        if (auto *ML = Context.getASTMutationListener())
+          ML->DeclarationMarkedOpenMPDeclareTarget(VD);
+      }
+      return;
+    }
+  }
+  if (!E) {
+    // Checking declaration inside declare target region.
+    if (!D->hasAttr<OMPDeclareTargetDeclAttr>() &&
+        (isa<VarDecl>(D) || isa<FunctionDecl>(D))) {
+      D->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(Context));
+      if (auto *ML = Context.getASTMutationListener())
+        ML->DeclarationMarkedOpenMPDeclareTarget(D);
+    }
+    return;
+  }
+  checkDeclInTargetContext(E->getExprLoc(), E->getSourceRange(), *this, D);
+}

lib/Serialization/ASTCommon.h

enum DeclUpdateKind {
   UPD_CXX_INSTANTIATED_DEFAULT_ARGUMENT,
   UPD_CXX_RESOLVED_DTOR_DELETE,
   UPD_CXX_RESOLVED_EXCEPTION_SPEC,
   UPD_CXX_DEDUCED_RETURN_TYPE,
   UPD_DECL_MARKED_USED,
   UPD_MANGLING_NUMBER,
   UPD_STATIC_LOCAL_NUMBER,
   UPD_DECL_MARKED_OPENMP_THREADPRIVATE,
+  UPD_DECL_MARKED_OPENMP_DECLARETARGET,
   UPD_DECL_EXPORTED,
   UPD_ADDED_ATTR_TO_RECORD
 };
 
 TypeIdx TypeIdxFromBuiltin(const BuiltinType *BT);
 
 template <typename IdxForTypeTy>
 TypeID MakeTypeID(ASTContext &Context, QualType T, IdxForTypeTy IdxForType) {

lib/Serialization/ASTReaderDecl.cpp

case UPD_STATIC_LOCAL_NUMBER:
       Reader.Context.setStaticLocalNumber(cast<VarDecl>(D), Record[Idx++]);
       break;
 
     case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
       D->addAttr(OMPThreadPrivateDeclAttr::CreateImplicit(
           Reader.Context, ReadSourceRange(Record, Idx)));
       break;
 
+    case UPD_DECL_MARKED_OPENMP_DECLARETARGET:
+      D->addAttr(OMPDeclareTargetDeclAttr::CreateImplicit(
+          Reader.Context, ReadSourceRange(Record, Idx)));
+      break;
+
     case UPD_DECL_EXPORTED: {
       unsigned SubmoduleID = readSubmoduleID(Record, Idx);
       auto *Exported = cast<NamedDecl>(D);
       if (auto *TD = dyn_cast<TagDecl>(Exported))
         Exported = TD->getDefinition();
       Module *Owner = SubmoduleID ? Reader.getSubmodule(SubmoduleID) : nullptr;
       if (Reader.getContext().getLangOpts().ModulesLocalVisibility) {
         // FIXME: This doesn't send the right notifications if there are

lib/Serialization/ASTWriter.cpp

for (auto &Update : DeclUpdate.second) {
         Record.push_back(Update.getNumber());
         break;
 
       case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
         AddSourceRange(D->getAttr<OMPThreadPrivateDeclAttr>()->getRange(),
                        Record);
         break;
 
+      case UPD_DECL_MARKED_OPENMP_DECLARETARGET:
+        AddSourceRange(D->getAttr<OMPDeclareTargetDeclAttr>()->getRange(),
+                       Record);
+        break;
+
       case UPD_DECL_EXPORTED:
         Record.push_back(getSubmoduleID(Update.getModule()));
         break;
 
       case UPD_ADDED_ATTR_TO_RECORD:
         WriteAttributes(llvm::makeArrayRef(Update.getAttr()), Record);
         break;
       }

 void ASTWriter::DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
 
   DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_MARKED_OPENMP_THREADPRIVATE));
 }
 
+void ASTWriter::DeclarationMarkedOpenMPDeclareTarget(const Decl *D) {
+  assert(!WritingAST && "Already writing the AST!");
+  if (!D->isFromASTFile())
+    return;
+
+  DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_MARKED_OPENMP_DECLARETARGET));
+}
+
 void ASTWriter::RedefinedHiddenDefinition(const NamedDecl *D, Module *M) {
   assert(!WritingAST && "Already writing the AST!");
   assert(D->isHidden() && "expected a hidden declaration");
   DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_EXPORTED, M));
 }
 
 void ASTWriter::AddedAttributeToRecord(const Attr *Attr,
                                        const RecordDecl *Record) {
   assert(!WritingAST && "Already writing the AST!");
   if (!Record->isFromASTFile())
     return;
   DeclUpdates[Record].push_back(DeclUpdate(UPD_ADDED_ATTR_TO_RECORD, Attr));
 }

lib/Serialization/ASTWriterDecl.cpp

 /// clients to use a separate API call to "realize" the decl. This should be
 /// relatively painless since they would presumably only do it for top-level
 /// decls.
 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
                            bool WritingModule) {
   // An ObjCMethodDecl is never considered as "required" because its
   // implementation container always is.
 
-  // File scoped assembly or obj-c implementation must be seen.
-  if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
+  // File scoped assembly or obj-c or OMP declare target implementation must be
+  // seen.
+  if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) ||
+      D->hasAttr<OMPDeclareTargetDeclAttr>())
     return true;
 
   // ImportDecl is used by codegen to determine the set of imported modules to
   // search for inputs for automatic linking; include it if it has a semantic
   // effect.
   if (isa<ImportDecl>(D) && !WritingModule)
     return true;
 

test/OpenMP/declare_target_ast_print.cpp

+// RUN: %clang_cc1 -verify -fopenmp -ast-print %s | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+#pragma omp declare target
+// CHECK: #pragma omp declare target
+
+void foo() {}
+// CHECK-NEXT: void foo()
+
+#pragma omp end declare target
+// CHECK: #pragma omp end declare target
+
+extern "C" {
+#pragma omp declare target
+// CHECK: #pragma omp declare target
+
+void foo_c() {}
+// CHECK-NEXT: void foo_c()
+
+#pragma omp end declare target
+// CHECK: #pragma omp end declare target
+}
+
+extern "C++" {
+#pragma omp declare target
+// CHECK: #pragma omp declare target
+
+void foo_cpp() {}
+// CHECK-NEXT: void foo_cpp()
+
+#pragma omp end declare target
+// CHECK: #pragma omp end declare target
+}
+
+int main (int argc, char **argv) {
+  foo();
+  foo_c();
+  foo_cpp();
+  return (0);
+}
+
+#endif

test/OpenMP/declare_target_messages.cpp

+// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify -fopenmp -fnoopenmp-use-tls -ferror-limit 100 -o - %s
+
+#pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
+
+int a, b; // expected-warning {{declaration is not declared in any declare target region}}
+__thread int t; // expected-note {{defined as threadprivate or thread local}}
+#pragma omp declare target private(a) // expected-warning {{extra tokens at the end of '#pragma omp declare target' are ignored}}
+void f();
+#pragma omp end declare target shared(a) // expected-warning {{extra tokens at the end of '#pragma omp end declare target' are ignored}}
+void c(); // expected-warning {{declaration is not declared in any declare target region}}
+
+extern int b;
+
+struct NonT {
+  int a;
+};
+
+typedef int sint;
+
+#pragma omp declare target // expected-note {{to match this '#pragma omp declare target'}}
+#pragma omp threadprivate(a) // expected-note {{defined as threadprivate or thread local}}
+extern int b;
+int g;
+
+struct T { // expected-note {{mappable type cannot be polymorphic}}
+  int a;
+  virtual int method();
+};
+
+class VC { // expected-note {{mappable type cannot be polymorphic}}
+  T member;
+  NonT member1;
+  public:
+    virtual int method() { T a; return 0; } // expected-error {{type 'T' is not mappable to target}}
+};
+
+struct C {
+  NonT a;
+  sint b;
+  int method();
+  int method1();
+};
+
+int C::method1() {
+  return 0;
+}
+
+void foo() {
+  a = 0; // expected-error {{threadprivate variables cannot be used in target constructs}}
+  b = 0; // expected-note {{used here}}
+  t = 1; // expected-error {{threadprivate variables cannot be used in target constructs}}
+  C object;
+  VC object1; // expected-error {{type 'VC' is not mappable to target}}
+  g = object.method();
+  g += object.method1();
+  g += object1.method();
+  f();
+  c(); // expected-note {{used here}}
+}
+#pragma omp declare target // expected-error {{expected '#pragma omp end declare target'}}
+void foo1() {}
+#pragma omp end declare target
+#pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
+
+int C::method() {
+  return 0;
+}
+
+struct S {
+#pragma omp declare target // expected-error {{directive must be at file or namespace scope}}
+  int v;
+#pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
+};
+
+int main (int argc, char **argv) {
+#pragma omp declare target // expected-error {{unexpected OpenMP directive '#pragma omp declare target'}}
+  int v;
+#pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
+  foo();
+  return (0);
+}
+
+namespace {
+#pragma omp declare target // expected-note {{to match this '#pragma omp declare target'}}
+  int x;
+} //  expected-error {{expected '#pragma omp end declare target'}}
+#pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
+
+#pragma omp declare target // expected-error {{expected '#pragma omp end declare target'}} expected-note {{to match this '#pragma omp declare target'}}

utils/TableGen/ClangAttrEmitter.cpp

 #include <memory>
 #include <set>
 #include <sstream>
 
 using namespace llvm;
 
 namespace {
 class FlattenedSpelling {
-  std::string V, N, NS;
+  std::string V, N, NS, E;
   bool K;
 
 public:
   FlattenedSpelling(const std::string &Variety, const std::string &Name,
-                    const std::string &Namespace, bool KnownToGCC) :
-    V(Variety), N(Name), NS(Namespace), K(KnownToGCC) {}
+                    const std::string &Namespace, const std::string &Ending,
+                    bool KnownToGCC) :
+    V(Variety), N(Name), NS(Namespace), E(Ending), K(KnownToGCC) {}
   explicit FlattenedSpelling(const Record &Spelling) :
     V(Spelling.getValueAsString("Variety")),
     N(Spelling.getValueAsString("Name")) {
 
     assert(V != "GCC" && "Given a GCC spelling, which means this hasn't been"
            "flattened!");
     if (V == "CXX11" || V == "Pragma")
       NS = Spelling.getValueAsString("Namespace");
+    if (V == "Pragma")
+      E = Spelling.getValueAsString("Ending");
     bool Unset;
     K = Spelling.getValueAsBitOrUnset("KnownToGCC", Unset);
   }
 
   const std::string &variety() const { return V; }
   const std::string &name() const { return N; }
   const std::string &nameSpace() const { return NS; }
+  const std::string &ending() const { return E; }
   bool knownToGCC() const { return K; }
 };
 } // end anonymous namespace
 
 static std::vector<FlattenedSpelling>
 GetFlattenedSpellings(const Record &Attr) {
   std::vector<Record *> Spellings = Attr.getValueAsListOfDefs("Spellings");
   std::vector<FlattenedSpelling> Ret;
 
   for (const auto &Spelling : Spellings) {
     if (Spelling->getValueAsString("Variety") == "GCC") {
       // Gin up two new spelling objects to add into the list.
-      Ret.emplace_back("GNU", Spelling->getValueAsString("Name"), "", true);
-      Ret.emplace_back("CXX11", Spelling->getValueAsString("Name"), "gnu",
+      Ret.emplace_back("GNU", Spelling->getValueAsString("Name"), "", "", true);
+      Ret.emplace_back("CXX11", Spelling->getValueAsString("Name"), "gnu", "",
                        true);
     } else
       Ret.push_back(FlattenedSpelling(*Spelling));
   }
 
   return Ret;
 }
 
writePrettyPrintFunction(Record &R,
   }
 
   // End of the switch statement.
   OS << "}\n";
   // End of the print function.
   OS << "}\n\n";
 }
 
+// Determines if an attribute has a Pragma spelling.
+static bool AttrHasPragmaSpelling(const Record *R) {
+  std::vector<FlattenedSpelling> Spellings = GetFlattenedSpellings(*R);
+  return std::find_if(Spellings.begin(), Spellings.end(),
+                      [](const FlattenedSpelling &S) {
+           return S.variety() == "Pragma";
+         }) != Spellings.end();
+}
+
+static void
+writePrettyPrintEndFunction(Record &R,
+                            const std::vector<std::unique_ptr<Argument>> &Args,
+                            raw_ostream &OS) {
+  std::vector<FlattenedSpelling> Spellings = GetFlattenedSpellings(R);
+
+  OS << "void " << R.getName() << "Attr::printPrettyEnd("
+    << "raw_ostream &OS, const PrintingPolicy &Policy) const {\n";
+
+  if (!AttrHasPragmaSpelling(&R)) {
+    OS << "}\n\n";
+    return;
+  }
+
+  OS <<
+    "  switch (SpellingListIndex) {\n"
+    "  default:\n"
+    "    llvm_unreachable(\"Unknown attribute spelling!\");\n"
+    "    break;\n";
+
+  for (unsigned I = 0; I < Spellings.size(); ++ I) {
+    if (Spellings[I].variety() != "Pragma")
+      continue;
+
+    OS << "  case " << I << " : {\n";
+    std::string Ending = Spellings[I].ending();
+    if (!Ending.empty()) {
+      llvm::SmallString<64> Spelling;
+      std::string Namespace = Spellings[I].nameSpace();
+      if (!Namespace.empty()) {
+        Spelling += Namespace;
+        Spelling += " ";
+      }
+      Spelling += Ending;
+
+      OS << "    OS << \"#pragma "  << Spelling << "\\n\";\n";
+
+    }
+    OS << "    break;\n";
+    OS << "  }\n";
+  }
+
+  // End of the switch statement.
+  OS << "}\n";
+  // End of the print function.
+  OS << "}\n\n";
+}
+
 /// \brief Return the index of a spelling in a spelling list.
 static unsigned
 getSpellingListIndex(const std::vector<FlattenedSpelling> &SpellingList,
                      const FlattenedSpelling &Spelling) {
   assert(!SpellingList.empty() && "Spelling list is empty!");
 
   for (unsigned Index = 0; Index < SpellingList.size(); ++Index) {
     const FlattenedSpelling &S = SpellingList[Index];
for (const auto *Attr : Attrs) {
     // Emit a constructor that takes all the non-fake, non-optional arguments.
     if (HasOptArg) {
       emitCtor(false, false);
     }
 
     OS << "  " << R.getName() << "Attr *clone(ASTContext &C) const;\n";
     OS << "  void printPretty(raw_ostream &OS,\n"
        << "                   const PrintingPolicy &Policy) const;\n";
+    OS << "  void printPrettyEnd(raw_ostream &OS,\n"
+       << "                      const PrintingPolicy &Policy) const;\n";
     OS << "  const char *getSpelling() const;\n";
     
     if (!ElideSpelling) {
       assert(!SemanticToSyntacticMap.empty() && "Empty semantic mapping list");
       OS << "  Spelling getSemanticSpelling() const {\n";
       WriteSemanticSpellingSwitch("SpellingListIndex", SemanticToSyntacticMap,
                                   OS);
       OS << "  }\n";
for (auto *Attr : Attrs) {
     }
     OS << ", getSpellingListIndex());\n";
     OS << "  A->Inherited = Inherited;\n";
     OS << "  A->IsPackExpansion = IsPackExpansion;\n";
     OS << "  A->Implicit = Implicit;\n";
     OS << "  return A;\n}\n\n";
 
     writePrettyPrintFunction(R, Args, OS);
+    writePrettyPrintEndFunction(R, Args, OS);
     writeGetSpellingFunction(R, OS);
   }
 
   // Instead of relying on virtual dispatch we just create a huge dispatch
   // switch. This is both smaller and faster than virtual functions.
   auto EmitFunc = [&](const char *Method) {
     OS << "  switch (getKind()) {\n";
     for (const auto *Attr : Attrs) {
void EmitClangAttrImpl(RecordKeeper &Records, raw_ostream &OS) {
   EmitFunc("getSpelling()");
 
   OS << "Attr *Attr::clone(ASTContext &C) const {\n";
   EmitFunc("clone(C)");
 
   OS << "void Attr::printPretty(raw_ostream &OS, "
         "const PrintingPolicy &Policy) const {\n";
   EmitFunc("printPretty(OS, Policy)");
+
+  OS << "void Attr::printPrettyEnd(raw_ostream &OS, "
+        "const PrintingPolicy &Policy) const {\n";
+  EmitFunc("printPrettyEnd(OS, Policy)");
 }
 
 } // end namespace clang
 
 static void emitAttrList(raw_ostream &OS, StringRef Class,
                          const std::vector<Record*> &AttrList) {
   for (auto Cur : AttrList) {
     OS << Class << "(" << Cur->getName() << ")\n";
   }
 }
 
-// Determines if an attribute has a Pragma spelling.
-static bool AttrHasPragmaSpelling(const Record *R) {
-  std::vector<FlattenedSpelling> Spellings = GetFlattenedSpellings(*R);
-  return std::find_if(Spellings.begin(), Spellings.end(),
-                      [](const FlattenedSpelling &S) {
-           return S.variety() == "Pragma";
-         }) != Spellings.end();
-}
-
 namespace {
   struct AttrClassDescriptor {
     const char * const MacroName;
     const char * const TableGenName;
   };
 }
 
 static const AttrClassDescriptor AttrClassDescriptors[] = {