[OPENMP51]Initial parsing/sema for adjust_args clause for 'declare variant'

[mikerice]

Summary

Adds initial parsing and sema for the 'adjust_args' clause.

Note that an AST clause is not created as it instead adds its expressions to the OMPDeclareVariantAttr.

[aaron.ballman]

clang/include/clang/Basic/DiagnosticSemaKinds.td

10626

clang/lib/Parse/ParseOpenMP.cpp

1447–1452

1453

Should this return IsError?

clang/lib/Sema/SemaOpenMP.cpp

7089–7094

7109

Do we have to worry about things like MemberExpr as well?

[mikerice]

Addressed review comments.

[mikerice]

Thanks for taking a look at this.

clang/lib/Parse/ParseOpenMP.cpp

1453

Possibly yes. If we return true we should cleanup the tokens before returning.
Returning false is probably okay here but we could end up with a bunch of cascading errors. I guess I prefer the former so I updated to that for a look.

clang/lib/Sema/SemaOpenMP.cpp

7109

I don't think so, or maybe I don't understand the question. They can specify only function parameters here and anything else is an error. It is also an error if the function parameter is specified more than once.

[aaron.ballman]

clang/lib/Sema/SemaOpenMP.cpp

7109

I don't think so, or maybe I don't understand the question.

It's most likely my near-complete ignorance of OpenMP showing through. :-D

They can specify only function parameters here and anything else is an error.

Ah, I was thinking they could refer to a member of a parameter. e.g., void foo(SomeStruct S); and they could refer to S.Whatever. But it sounds like that's explicitly not allowed?

[mikerice]

Remove unused variable.

clang/lib/Sema/SemaOpenMP.cpp

7109

Right, that's not allowed.

[ABataev]

clang/include/clang/Basic/OpenMPKinds.h

173

OMPC_ADJUST_ARGS_unknown,?

clang/lib/Sema/SemaOpenMP.cpp

7073–7074

Why MutableArrayRef, not just ArrayRef?

[mikerice]

Addressed review comments, fixed switch warning.

[mikerice]

Rebased

[mikerice]

Ping. @jdoerfert any comments on this? Anyone else?

[ABataev]

clang/lib/Parse/ParseOpenMP.cpp

1406–1413

Maybe turn it into while {} form? What if the clause is early terminated?

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

484–491

No need for outer if

492–499

No need for outer if

[mikerice]

Addressed review comments.

clang/lib/Parse/ParseOpenMP.cpp

1406–1413

Rewrote this to parse the clauses in the loop here instead of the separate function, which seems better now that there is more than one clause possible.

[aaron.ballman]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

I know this is code that existed previously, but why the while loop? This strikes me as a potential infinite loop because SkipUntil returns false when the token is not found, so if the token is not found the first time, I'd be surprised if a second pass at it finds the token.

2051

Same question here as above.

3987–3990

ExpectAndConsume?

[ABataev]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

It may return early because of parens/braces etc. counting. In this case, it will return false while if annot_pragma_openmp_end is found, it returns true. We need to iterate to the end of the directive here, that's why there is a loop.

[aaron.ballman]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

Thank you for the explanation -- that sure sounds like a bug with SkipUntil to me, and looking through the code base, the only code that seems to do this dance is OpenMP code. Do you happen to have a code example that requires the loop behavior?

(Not suggesting a change needs to be made in this patch, I'm mostly wondering if there's a change we can make in a follow-up and remove these loops.)

[ABataev]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

OpenMP implementation guarantees that the directives are started by annot_pragma_openmp_begin and terminated by annot_pragma_openmp_end. That's why we always trying to find the terminating annot_pragma_openmp_end to recover the parsing errors in OpenMP correctly, so the parser could start parsing regular C/C++ code rather than starting parsing in the middle of the OpenMP directive.
There are some tests in test/OpenMP directory that checks for this but I don't remember which one exactly.
I think SkipUntil works correctly for the regular C/C++ code, it is just a special corner case for the pragmas

[aaron.ballman]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

OpenMP implementation guarantees that the directives are started by annot_pragma_openmp_begin and terminated by annot_pragma_openmp_end. That's why we always trying to find the terminating annot_pragma_openmp_end to recover the parsing errors in OpenMP correctly, so the parser could start parsing regular C/C++ code rather than starting parsing in the middle of the OpenMP directive.

My expectation is that calling SkipUntil(annot_pragma_openmp_end) should skip until it hits the given annotation token, the end of directive marker, or the end of file marker. It should not require a while loop to reach the given token properly. Either the call returns true because it found the token, or it returns false and it advanced the token to some reasonable stopping point that I would expect is outside of the stream of directive tokens.

Given that there is a guarantee that the directive ends with a annot_pragma_openmp_end, I don't see why a loop should be necessary for callers (one may be necessary within SkipUntil, obviously).

[ABataev]

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

We need to disable braces/parens counting in SkipUntil for some cases to avoid loops.

[mikerice]

Sorry for the long delay. Rebased and addressed comments.

[aaron.ballman]

LGTM aside from some nits.

clang/lib/Parse/ParseOpenMP.cpp

1447–1448

That continues to sound like a bug with SkipUntil() to me, but one that's orthogonal to this patch.

3989

You should fix the formatting issue.

clang/lib/Sema/SemaOpenMP.cpp

7123

clang/include/clang/Basic/Attr.td

def OMPDeclareVariant : InheritableAttr {
   let Subjects = SubjectList<[Function]>;
   let SemaHandler = 0;
   let HasCustomParsing = 1;
   let InheritEvenIfAlreadyPresent = 1;
   let Documentation = [OMPDeclareVariantDocs];
   let Args = [
     ExprArgument<"VariantFuncRef">,
     OMPTraitInfoArgument<"TraitInfos">,
+    VariadicExprArgument<"AdjustArgsNothing">,
+    VariadicExprArgument<"AdjustArgsNeedDevicePtr">
   ];
   let AdditionalMembers = [{
     OMPTraitInfo &getTraitInfo() { return *traitInfos; }
     void printPrettyPragma(raw_ostream & OS, const PrintingPolicy &Policy)
         const;
   }];
 }
 

clang/include/clang/Basic/DiagnosticParseKinds.td

def err_omp_declare_target_unexpected_clause: Error<
   "unexpected '%0' clause, only %select{'to' or 'link'|'to', 'link' or 'device_type'}1 clauses expected">;
 def err_omp_expected_clause: Error<
   "expected at least one clause on '#pragma omp %0' directive">;
 def err_omp_mapper_illegal_identifier : Error<
   "illegal OpenMP user-defined mapper identifier">;
 def err_omp_mapper_expected_declarator : Error<
   "expected declarator on 'omp declare mapper' directive">;
 def err_omp_declare_variant_wrong_clause : Error<
-  "expected '%0' clause on 'omp declare variant' directive">;
+  "expected %select{'match'|'match' or 'adjust_args'}0 clause on "
+  "'omp declare variant' directive">;
 def err_omp_declare_variant_duplicate_nested_trait : Error<
   "nested OpenMP context selector contains duplicated trait '%0'"
   " in selector '%1' and set '%2' with different score">;
 def err_omp_declare_variant_nested_user_condition : Error<
   "nested user conditions in OpenMP context selector not supported (yet)">;
 def warn_omp_declare_variant_string_literal_or_identifier
     : Warning<"expected identifier or string literal describing a context "
               "%select{set|selector|property}0; "

clang/include/clang/Basic/DiagnosticSemaKinds.td

def err_omp_interop_prefer_type : Error<
   "expression">;
 def err_omp_interop_bad_depend_clause : Error<
   "'depend' clause requires the 'targetsync' interop type">;
 def err_omp_interop_var_multiple_actions : Error<
   "interop variable %0 used in multiple action clauses">;
 def err_omp_dispatch_statement_call
     : Error<"statement after '#pragma omp dispatch' must be a direct call"
             " to a target function or an assignment to one">;
+def err_omp_adjust_arg_multiple_clauses : Error<
+  "'adjust_arg' argument %0 used in multiple clauses">;
+def err_omp_clause_requires_dispatch_construct : Error<
+  "'%0' clause requires 'dispatch' context selector">;
 } // end of OpenMP category
 
 let CategoryName = "Related Result Type Issue" in {
 // Objective-C related result type compatibility
 def warn_related_result_type_compatibility_class : Warning<
   "method is expected to return an instance of its class type "
   "%diff{$, but is declared to return $|"
   ", but is declared to return different type}0,1">;

clang/include/clang/Basic/OpenMPKinds.h

 
 /// OpenMP modifiers for 'reduction' clause.
 enum OpenMPReductionClauseModifier {
 #define OPENMP_REDUCTION_MODIFIER(Name) OMPC_REDUCTION_##Name,
 #include "clang/Basic/OpenMPKinds.def"
   OMPC_REDUCTION_unknown,
 };
 
+/// OpenMP adjust-op kinds for 'adjust_args' clause.
+enum OpenMPAdjustArgsOpKind {
+#define OPENMP_ADJUST_ARGS_KIND(Name) OMPC_ADJUST_ARGS_##Name,
+#include "clang/Basic/OpenMPKinds.def"
+  OMPC_ADJUST_ARGS_unknown
+};
+
 unsigned getOpenMPSimpleClauseType(OpenMPClauseKind Kind, llvm::StringRef Str,
                                    unsigned OpenMPVersion);
 const char *getOpenMPSimpleClauseTypeName(OpenMPClauseKind Kind, unsigned Type);
 
 /// Checks if the specified directive is a directive with an associated
 /// loop construct.
 /// \param DKind Specified directive.
 /// \return true - the directive is a loop-associated directive like 'omp simd'

clang/include/clang/Basic/OpenMPKinds.def

 #define OPENMP_ORDER_KIND(Name)
 #endif
 #ifndef OPENMP_DEVICE_MODIFIER
 #define OPENMP_DEVICE_MODIFIER(Name)
 #endif
 #ifndef OPENMP_REDUCTION_MODIFIER
 #define OPENMP_REDUCTION_MODIFIER(Name)
 #endif
+#ifndef OPENMP_ADJUST_ARGS_KIND
+#define OPENMP_ADJUST_ARGS_KIND(Name)
+#endif
 
 // Static attributes for 'schedule' clause.
 OPENMP_SCHEDULE_KIND(static)
 OPENMP_SCHEDULE_KIND(dynamic)
 OPENMP_SCHEDULE_KIND(guided)
 OPENMP_SCHEDULE_KIND(auto)
 OPENMP_SCHEDULE_KIND(runtime)
 

 // Type of the 'order' clause.
 OPENMP_ORDER_KIND(concurrent)
 
 // Modifiers for 'reduction' clause.
 OPENMP_REDUCTION_MODIFIER(default)
 OPENMP_REDUCTION_MODIFIER(inscan)
 OPENMP_REDUCTION_MODIFIER(task)
 
+// Adjust-op kinds for the 'adjust_args' clause.
+OPENMP_ADJUST_ARGS_KIND(nothing)
+OPENMP_ADJUST_ARGS_KIND(need_device_ptr)
+
+#undef OPENMP_ADJUST_ARGS_KIND
 #undef OPENMP_REDUCTION_MODIFIER
 #undef OPENMP_DEVICE_MODIFIER
 #undef OPENMP_ORDER_KIND
 #undef OPENMP_LASTPRIVATE_KIND
 #undef OPENMP_DEVICE_TYPE_KIND
 #undef OPENMP_LINEAR_KIND
 #undef OPENMP_DEPEND_KIND
 #undef OPENMP_SCHEDULE_MODIFIER

clang/include/clang/Parse/Parser.h

private:
 
   /// Parses an OpenMP context selector set.
   void parseOMPContextSelectorSet(OMPTraitSet &TISet,
                                   llvm::StringMap<SourceLocation> &SeenSets);
 
   /// Parses OpenMP context selectors.
   bool parseOMPContextSelectors(SourceLocation Loc, OMPTraitInfo &TI);
 
+  /// Parse a `match` or 'adjust_args' clause for an
+  /// '#pragma omp declare variant'. Return true if there was an error.
+  bool
+  parseOMPDeclareVariantAnyClause(SourceLocation Loc, OMPTraitInfo &TI,
+                                  OMPTraitInfo *ParentTI,
+                                  SmallVectorImpl<Expr *> &AdjustNothing,
+                                  SmallVectorImpl<Expr *> &AdjustNeedDevicePtr);
+
   /// Parse a `match` clause for an '#pragma omp declare variant'. Return true
   /// if there was an error.
   bool parseOMPDeclareVariantMatchClause(SourceLocation Loc, OMPTraitInfo &TI,
                                          OMPTraitInfo *ParentTI);
 
   /// Parse clauses for '#pragma omp declare variant'.
   void ParseOMPDeclareVariantClauses(DeclGroupPtrTy Ptr, CachedTokens &Toks,
                                      SourceLocation Loc);

clang/include/clang/Sema/Sema.h

public:
 
   /// Called on well-formed '\#pragma omp declare variant' after parsing of
   /// the associated method/function.
   /// \param FD Function declaration to which declare variant directive is
   /// applied to.
   /// \param VariantRef Expression that references the variant function, which
   /// must be used instead of the original one, specified in \p DG.
   /// \param TI The context traits associated with the function variant.
-  void ActOnOpenMPDeclareVariantDirective(FunctionDecl *FD, Expr *VariantRef,
-                                          OMPTraitInfo &TI, SourceRange SR);
+  void ActOnOpenMPDeclareVariantDirective(
+      FunctionDecl *FD, Expr *VariantRef, OMPTraitInfo &TI,
+      MutableArrayRef<Expr *> AdjustArgsNothing,
+      MutableArrayRef<Expr *> AdjustArgsNeedDevicePtr, SourceRange SR);
 
   OMPClause *ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind,
                                          Expr *Expr,
                                          SourceLocation StartLoc,
                                          SourceLocation LParenLoc,
                                          SourceLocation EndLoc);
   /// Called on well-formed 'allocator' clause.
   OMPClause *ActOnOpenMPAllocatorClause(Expr *Allocator,

clang/lib/AST/AttrImpl.cpp

 void OMPDeclareVariantAttr::printPrettyPragma(
     raw_ostream &OS, const PrintingPolicy &Policy) const {
   if (const Expr *E = getVariantFuncRef()) {
     OS << "(";
     E->printPretty(OS, nullptr, Policy);
     OS << ")";
   }
   OS << " match(" << traitInfos << ")";
+
+  auto PrintExprs = [&OS, &Policy](Expr **Begin, Expr **End) {
+    for (Expr **I = Begin; I != End; ++I) {
+      assert(*I && "Expected non-null Stmt");
+      if (I != Begin)
+        OS << ",";
+      (*I)->printPretty(OS, nullptr, Policy);
+    }
+  };
+  if (adjustArgsNothing_size()) {
+    OS << " adjust_args(nothing:";
+    PrintExprs(adjustArgsNothing_begin(), adjustArgsNothing_end());
+    OS << ")";
+  }
+  if (adjustArgsNeedDevicePtr_size()) {
+    OS << " adjust_args(need_device_ptr:";
+    PrintExprs(adjustArgsNeedDevicePtr_begin(), adjustArgsNeedDevicePtr_end());
+    OS << ")";
+  }
 }
 
 #include "clang/AST/AttrImpl.inc"

clang/lib/Basic/OpenMPKinds.cpp

 #define OPENMP_DEVICE_MODIFIER(Name) .Case(#Name, OMPC_DEVICE_##Name)
 #include "clang/Basic/OpenMPKinds.def"
         .Default(OMPC_DEVICE_unknown);
   case OMPC_reduction:
     return llvm::StringSwitch<OpenMPReductionClauseModifier>(Str)
 #define OPENMP_REDUCTION_MODIFIER(Name) .Case(#Name, OMPC_REDUCTION_##Name)
 #include "clang/Basic/OpenMPKinds.def"
         .Default(OMPC_REDUCTION_unknown);
+  case OMPC_adjust_args:
+    return llvm::StringSwitch<OpenMPAdjustArgsOpKind>(Str)
+#define OPENMP_ADJUST_ARGS_KIND(Name) .Case(#Name, OMPC_ADJUST_ARGS_##Name)
+#include "clang/Basic/OpenMPKinds.def"
+        .Default(OMPC_ADJUST_ARGS_unknown);
   case OMPC_unknown:
   case OMPC_threadprivate:
   case OMPC_if:
   case OMPC_final:
   case OMPC_num_threads:
   case OMPC_safelen:
   case OMPC_simdlen:
   case OMPC_sizes:
case OMPC_reduction:
     case OMPC_REDUCTION_unknown:
       return "unknown";
 #define OPENMP_REDUCTION_MODIFIER(Name)                                        \
   case OMPC_REDUCTION_##Name:                                                  \
     return #Name;
 #include "clang/Basic/OpenMPKinds.def"
     }
     llvm_unreachable("Invalid OpenMP 'reduction' clause modifier");
+  case OMPC_adjust_args:
+    switch (Type) {
+    case OMPC_ADJUST_ARGS_unknown:
+      return "unknown";
+#define OPENMP_ADJUST_ARGS_KIND(Name)                                          \
+  case OMPC_ADJUST_ARGS_##Name:                                                \
+    return #Name;
+#include "clang/Basic/OpenMPKinds.def"
+    }
+    llvm_unreachable("Invalid OpenMP 'adjust_args' clause kind");
   case OMPC_unknown:
   case OMPC_threadprivate:
   case OMPC_if:
   case OMPC_final:
   case OMPC_num_threads:
   case OMPC_safelen:
   case OMPC_simdlen:
   case OMPC_sizes:

clang/lib/Parse/ParseOpenMP.cpp

if (!AssociatedFunction.isUsable()) {
     // Skip the last annot_pragma_openmp_end.
     (void)ConsumeAnnotationToken();
     return;
   }
 
   OMPTraitInfo *ParentTI = Actions.getOMPTraitInfoForSurroundingScope();
   ASTContext &ASTCtx = Actions.getASTContext();
   OMPTraitInfo &TI = ASTCtx.getNewOMPTraitInfo();
-  if (parseOMPDeclareVariantMatchClause(Loc, TI, ParentTI))
+  SmallVector<Expr *, 6> AdjustNothing;
+  SmallVector<Expr *, 6> AdjustNeedDevicePtr;
+  do {
+    if (parseOMPDeclareVariantAnyClause(Loc, TI, ParentTI, AdjustNothing,
+                                        AdjustNeedDevicePtr))
       return;
+    // Skip ',' if any.
+    if (Tok.is(tok::comma))
+      ConsumeToken();
+  } while (Tok.isNot(tok::annot_pragma_openmp_end));
 
   Optional<std::pair<FunctionDecl *, Expr *>> DeclVarData =
       Actions.checkOpenMPDeclareVariantFunction(
           Ptr, AssociatedFunction.get(), TI,
           SourceRange(Loc, Tok.getLocation()));
 
-  // Skip last tokens.
-  while (Tok.isNot(tok::annot_pragma_openmp_end))
-    ConsumeAnyToken();
   if (DeclVarData && !TI.Sets.empty())
     Actions.ActOnOpenMPDeclareVariantDirective(
-        DeclVarData->first, DeclVarData->second, TI,
-        SourceRange(Loc, Tok.getLocation()));
+        DeclVarData->first, DeclVarData->second, TI, AdjustNothing,
+        AdjustNeedDevicePtr, SourceRange(Loc, Tok.getLocation()));
 
   // Skip the last annot_pragma_openmp_end.
   (void)ConsumeAnnotationToken();
 }
 
+bool Parser::parseOMPDeclareVariantAnyClause(
+    SourceLocation Loc, OMPTraitInfo &TI, OMPTraitInfo *ParentTI,
+    SmallVectorImpl<Expr *> &AdjustNothing,
+    SmallVectorImpl<Expr *> &AdjustNeedDevicePtr) {
+  OpenMPClauseKind CKind = Tok.isAnnotation()
+                               ? OMPC_unknown
+                               : getOpenMPClauseKind(PP.getSpelling(Tok));
+  if (CKind == OMPC_adjust_args &&
+      isAllowedClauseForDirective(OMPD_declare_variant, CKind,
+                                  getLangOpts().OpenMP)) {
+    ConsumeToken();
+    Parser::OpenMPVarListDataTy Data;
+    SmallVector<Expr *> Vars;
+
+    if (ParseOpenMPVarList(OMPD_declare_variant, OMPC_adjust_args, Vars,
+                           Data)) {
+      while (!SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch))
+        ;
+      // Skip the last annot_pragma_openmp_end.
+      (void)ConsumeAnnotationToken();
+      return true;
+    }
+    llvm::append_range(Data.ExtraModifier == OMPC_ADJUST_ARGS_nothing
+                           ? AdjustNothing
+                           : AdjustNeedDevicePtr,
+                       Vars);
+    return false;
+  }
+  if (CKind != OMPC_match) {
+    Diag(Tok.getLocation(), diag::err_omp_declare_variant_wrong_clause)
+        << (getLangOpts().OpenMP < 51 ? 0 : 1);
+    while (!SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch))
+      ;
+    // Skip the last annot_pragma_openmp_end.
+    (void)ConsumeAnnotationToken();
+    return true;
+  }
+  return parseOMPDeclareVariantMatchClause(Loc, TI, ParentTI);
+}
+
 bool Parser::parseOMPDeclareVariantMatchClause(SourceLocation Loc,
                                                OMPTraitInfo &TI,
                                                OMPTraitInfo *ParentTI) {
   // Parse 'match'.
   OpenMPClauseKind CKind = Tok.isAnnotation()
                                ? OMPC_unknown
                                : getOpenMPClauseKind(PP.getSpelling(Tok));
   if (CKind != OMPC_match) {
     Diag(Tok.getLocation(), diag::err_omp_declare_variant_wrong_clause)
-        << getOpenMPClauseName(OMPC_match);
+        << (getLangOpts().OpenMP < 51 ? 0 : 1);
     while (!SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch))
       ;
     // Skip the last annot_pragma_openmp_end.
     (void)ConsumeAnnotationToken();
     return true;
   }
   (void)ConsumeToken();
   // Parse '('.
case OMPD_begin_declare_variant: {
     // <function-declaration-or-definition-sequence>
     // { #pragma omp end declare variant }
     //
     ConsumeToken();
     OMPTraitInfo *ParentTI = Actions.getOMPTraitInfoForSurroundingScope();
     ASTContext &ASTCtx = Actions.getASTContext();
     OMPTraitInfo &TI = ASTCtx.getNewOMPTraitInfo();
     if (parseOMPDeclareVariantMatchClause(Loc, TI, ParentTI))
       break;
 
     // Skip last tokens.
     skipUntilPragmaOpenMPEnd(OMPD_begin_declare_variant);
 
     ParsingOpenMPDirectiveRAII NormalScope(*this, /*Value=*/false);
 
     VariantMatchInfo VMI;
     TI.getAsVariantMatchInfo(ASTCtx, VMI);
if (Tail.isUsable()) {
       }
     } else {
       // Parsing was unsuccessfull, revert and skip to the end of clause or
       // directive.
       TPA.Revert();
       SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
     }
+  } else if (Kind == OMPC_adjust_args) {
+    // Handle adjust-op for adjust_args clause.
+    ColonProtectionRAIIObject ColonRAII(*this);
+    Data.ExtraModifier = getOpenMPSimpleClauseType(
+        Kind, Tok.is(tok::identifier) ? PP.getSpelling(Tok) : "",
+        getLangOpts().OpenMP);
+    Data.ExtraModifierLoc = Tok.getLocation();
+    if (Data.ExtraModifier == OMPC_ADJUST_ARGS_unknown) {
+      SkipUntil(tok::colon, tok::r_paren, tok::annot_pragma_openmp_end,
+                StopBeforeMatch);
+    } else {
+      ConsumeToken();
+      if (Tok.is(tok::colon))
+        Data.ColonLoc = ConsumeToken();
+      else
+        Diag(Tok, diag::warn_pragma_expected_colon) << "adjust-op";
+    }
   }
 
   bool IsComma =
       (Kind != OMPC_reduction && Kind != OMPC_task_reduction &&
        Kind != OMPC_in_reduction && Kind != OMPC_depend && Kind != OMPC_map) ||
       (Kind == OMPC_reduction && !InvalidReductionId) ||
       (Kind == OMPC_map && Data.ExtraModifier != OMPC_MAP_unknown) ||
-      (Kind == OMPC_depend && Data.ExtraModifier != OMPC_DEPEND_unknown);
+      (Kind == OMPC_depend && Data.ExtraModifier != OMPC_DEPEND_unknown) ||
+      (Kind == OMPC_adjust_args &&
+       Data.ExtraModifier != OMPC_ADJUST_ARGS_unknown);
   const bool MayHaveTail = (Kind == OMPC_linear || Kind == OMPC_aligned);
   while (IsComma || (Tok.isNot(tok::r_paren) && Tok.isNot(tok::colon) &&
                      Tok.isNot(tok::annot_pragma_openmp_end))) {
     ParseScope OMPListScope(this, Scope::OpenMPDirectiveScope);
     ColonProtectionRAIIObject ColonRAII(*this, MayHaveTail);
     // Parse variable
     ExprResult VarExpr =
         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());

clang/lib/Sema/SemaOpenMP.cpp

else
     FD = cast<FunctionDecl>(D);
   auto *VariantFuncRef = DeclRefExpr::Create(
       Context, NestedNameSpecifierLoc(), SourceLocation(), FD,
       /* RefersToEnclosingVariableOrCapture */ false,
       /* NameLoc */ FD->getLocation(), FD->getType(), ExprValueKind::VK_RValue);
 
   OMPDeclareVariantScope &DVScope = OMPDeclareVariantScopes.back();
   auto *OMPDeclareVariantA = OMPDeclareVariantAttr::CreateImplicit(
-      Context, VariantFuncRef, DVScope.TI);
+      Context, VariantFuncRef, DVScope.TI,
+      /*NothingArgs=*/nullptr, /*NothingArgsSize=*/0,
+      /*NeedDevicePtrArgs=*/nullptr, /*NeedDevicePtrArgsSize=*/0);
   for (FunctionDecl *BaseFD : Bases)
     BaseFD->addAttr(OMPDeclareVariantA);
 }
 
 ExprResult Sema::ActOnOpenMPCall(ExprResult Call, Scope *Scope,
                                  SourceLocation LParenLoc,
                                  MultiExprArg ArgExprs,
                                  SourceLocation RParenLoc, Expr *ExecConfig) {
if (areMultiversionVariantFunctionsCompatible(
                               PDiag(diag::err_omp_declare_variant_diff)
                                   << FD->getLocation()),
           /*TemplatesSupported=*/true, /*ConstexprSupported=*/false,
           /*CLinkageMayDiffer=*/true))
     return None;
   return std::make_pair(FD, cast<Expr>(DRE));
 }
 
-void Sema::ActOnOpenMPDeclareVariantDirective(FunctionDecl *FD,
-                                              Expr *VariantRef,
-                                              OMPTraitInfo &TI,
-                                              SourceRange SR) {
-  auto *NewAttr =
-      OMPDeclareVariantAttr::CreateImplicit(Context, VariantRef, &TI, SR);
+void Sema::ActOnOpenMPDeclareVariantDirective(
+    FunctionDecl *FD, Expr *VariantRef, OMPTraitInfo &TI,
+    MutableArrayRef<Expr *> AdjustArgsNothing,
+    MutableArrayRef<Expr *> AdjustArgsNeedDevicePtr, SourceRange SR) {
+
+  // OpenMP 5.1 [2.3.5, declare variant directive, Restrictions]
+  // An adjust_args clause or append_args clause can only be specified if the
+  // dispatch selector of the construct selector set appears in the match
+  // clause.
+
+  SmallVector<Expr *, 8> AllAdjustArgs;
+  llvm::append_range(AllAdjustArgs, AdjustArgsNothing);
+  llvm::append_range(AllAdjustArgs, AdjustArgsNeedDevicePtr);
+
+  if (!AllAdjustArgs.empty()) {
+    VariantMatchInfo VMI;
+    bool Found = false;
+    TI.getAsVariantMatchInfo(Context, VMI);
+    if (!llvm::is_contained(
+            VMI.ConstructTraits,
+            llvm::omp::TraitProperty::construct_dispatch_dispatch)) {
+      Diag(AllAdjustArgs[0]->getExprLoc(),
+           diag::err_omp_clause_requires_dispatch_construct)
+          << getOpenMPClauseName(OMPC_adjust_args);
+      return;
+    }
+  }
+
+  // OpenMP 5.1 [2.3.5, declare variant directive, Restrictions]
+  // Each argument can only appear in a single adjust_args clause for each
+  // declare variant directive.
+  llvm::SmallPtrSet<const VarDecl *, 4> AdjustVars;
+
+  for (Expr *E : AllAdjustArgs) {
+    E = E->IgnoreParenImpCasts();
+    if (const auto *DRE = dyn_cast<DeclRefExpr>(E)) {
+      if (const auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
+        const VarDecl *CanonPVD = PVD->getCanonicalDecl();
+        if (FD->getNumParams() > PVD->getFunctionScopeIndex() &&
+            FD->getParamDecl(PVD->getFunctionScopeIndex())
+                    ->getCanonicalDecl() == CanonPVD) {
+          // It's a parameter of the function, check duplicates.
+          if (!AdjustVars.insert(CanonPVD).second) {
+            Diag(DRE->getLocation(), diag::err_omp_adjust_arg_multiple_clauses)
+                << PVD;
+            return;
+          }
+          continue;
+        }
+      }
+    }
+    // Anything that is not a function parameter is an error.
+    Diag(E->getExprLoc(), diag::err_omp_param_or_this_in_clause)
+        << FD->getDeclName() << 0;
+    return;
+  }
+
+  auto *NewAttr = OMPDeclareVariantAttr::CreateImplicit(
+      Context, VariantRef, &TI, AdjustArgsNothing.data(),
+      AdjustArgsNothing.size(), AdjustArgsNeedDevicePtr.data(),
+      AdjustArgsNeedDevicePtr.size(), SR);
   FD->addAttr(NewAttr);
 }
 
 StmtResult Sema::ActOnOpenMPParallelDirective(ArrayRef<OMPClause *> Clauses,
                                               Stmt *AStmt,
                                               SourceLocation StartLoc,
                                               SourceLocation EndLoc) {
   if (!AStmt)

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

if (auto *VariantFD = dyn_cast<FunctionDecl>(VariantDRE->getDecl())) {
                                 SourceLocation(), SubstFD,
                                 /* RefersToEnclosingVariableOrCapture */ false,
                                 /* NameLoc */ SubstFD->getLocation(),
                                 SubstFD->getType(), ExprValueKind::VK_RValue);
       }
     }
   }
 
-  S.ActOnOpenMPDeclareVariantDirective(FD, E, TI, Attr.getRange());
+  SmallVector<Expr *, 8> NothingExprs;
+  SmallVector<Expr *, 8> NeedDevicePtrExprs;
+  if (Attr.adjustArgsNothing_size()) {
+    for (Expr *E : Attr.adjustArgsNothing()) {
+      ExprResult ER = Subst(E);
+      if (ER.isInvalid())
+        continue;
+      NothingExprs.push_back(ER.get());
+    }
+  }
+  if (Attr.adjustArgsNeedDevicePtr_size()) {
+    for (Expr *E : Attr.adjustArgsNeedDevicePtr()) {
+      ExprResult ER = Subst(E);
+      if (ER.isInvalid())
+        continue;
+      NeedDevicePtrExprs.push_back(ER.get());
+    }
+  }
+  S.ActOnOpenMPDeclareVariantDirective(FD, E, TI, NothingExprs,
+                                       NeedDevicePtrExprs, Attr.getRange());
 }
 
 static void instantiateDependentAMDGPUFlatWorkGroupSizeAttr(
     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
     const AMDGPUFlatWorkGroupSizeAttr &Attr, Decl *New) {
   // Both min and max expression are constant expressions.
   EnterExpressionEvaluationContext Unevaluated(
       S, Sema::ExpressionEvaluationContext::ConstantEvaluated);

clang/test/OpenMP/declare_variant_clauses_ast_print.cpp

+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -fsyntax-only -verify -o - %s
+
+//RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                      \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                          \
+//RUN:   -fsyntax-only -verify -o - %s
+
+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -emit-pch -o %t %s
+
+// expected-no-diagnostics
+
+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -ast-print %s | FileCheck %s --check-prefix=PRINT
+
+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -ast-dump %s | FileCheck %s --check-prefix=DUMP
+
+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -include-pch %t -ast-print %s | FileCheck %s --check-prefix=PRINT
+
+//RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fopenmp -fopenmp-version=51 \
+//RUN:   -x c++ -std=c++14 -fexceptions -fcxx-exceptions                   \
+//RUN:   -Wno-source-uses-openmp -Wno-openmp-clauses                       \
+//RUN:   -include-pch %t -ast-dump-all %s | FileCheck %s --check-prefix=DUMP
+
+#ifndef HEADER
+#define HEADER
+
+void foo_v1(float *AAA, float *BBB, int *I) {return;}
+void foo_v2(float *AAA, float *BBB, int *I) {return;}
+void foo_v3(float *AAA, float *BBB, int *I) {return;}
+
+//DUMP: FunctionDecl{{.*}} foo 'void (float *, float *, int *)'
+//DUMP: OMPDeclareVariantAttr{{.*}}device={arch(x86, x86_64)}
+//DUMP: DeclRefExpr{{.*}}Function{{.*}}foo_v3
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'I'
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'BBB'
+//DUMP: OMPDeclareVariantAttr{{.*}}device={arch(ppc)}
+//DUMP: DeclRefExpr{{.*}}Function{{.*}}foo_v2
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'AAA'
+//DUMP: OMPDeclareVariantAttr{{.*}}device={arch(arm)}
+//DUMP: DeclRefExpr{{.*}}Function{{.*}}foo_v1
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'AAA'
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'BBB'
+//PRINT: #pragma omp declare variant(foo_v3) match(construct={dispatch}, device={arch(x86, x86_64)}) adjust_args(nothing:I) adjust_args(need_device_ptr:BBB)
+
+//PRINT: #pragma omp declare variant(foo_v2) match(construct={dispatch}, device={arch(ppc)}) adjust_args(need_device_ptr:AAA)
+
+//PRINT: omp declare variant(foo_v1) match(construct={dispatch}, device={arch(arm)}) adjust_args(need_device_ptr:AAA,BBB)
+
+#pragma omp declare variant(foo_v1)                        \
+   match(construct={dispatch}, device={arch(arm)})         \
+   adjust_args(need_device_ptr:AAA,BBB)
+
+#pragma omp declare variant(foo_v2)                        \
+   match(construct={dispatch}, device={arch(ppc)}),        \
+   adjust_args(need_device_ptr:AAA)
+
+#pragma omp declare variant(foo_v3)                        \
+   adjust_args(need_device_ptr:BBB) adjust_args(nothing:I) \
+   match(construct={dispatch}, device={arch(x86,x86_64)})
+
+void foo(float *AAA, float *BBB, int *I) {return;}
+
+void Foo_Var(float *AAA, float *BBB) {return;}
+
+#pragma omp declare variant(Foo_Var) \
+   match(construct={dispatch}, device={arch(x86_64)}) \
+   adjust_args(need_device_ptr:AAA) adjust_args(nothing:BBB)
+template<typename T>
+void Foo(T *AAA, T *BBB) {return;}
+
+//PRINT: #pragma omp declare variant(Foo_Var) match(construct={dispatch}, device={arch(x86_64)}) adjust_args(nothing:BBB) adjust_args(need_device_ptr:AAA)
+//DUMP: FunctionDecl{{.*}} Foo 'void (T *, T *)'
+//DUMP: OMPDeclareVariantAttr{{.*}}device={arch(x86_64)}
+//DUMP: DeclRefExpr{{.*}}Function{{.*}}Foo_Var
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'BBB'
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'AAA'
+//
+//DUMP: FunctionDecl{{.*}} Foo 'void (float *, float *)'
+//DUMP: OMPDeclareVariantAttr{{.*}}device={arch(x86_64)}
+//DUMP: DeclRefExpr{{.*}}Function{{.*}}Foo_Var
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'BBB'
+//DUMP: DeclRefExpr{{.*}}ParmVar{{.*}}'AAA'
+
+void func()
+{
+  float *A;
+  float *B;
+
+  //#pragma omp dispatch
+  Foo(A, B);
+}
+
+#endif // HEADER

clang/test/OpenMP/declare_variant_clauses_messages.cpp

+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -DOMP51 -std=c++11 -o - %s
+
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=50 -DOMP50 -std=c++11 -o - %s
+
+int Other;
+
+void foo_v1(float *AAA, float *BBB, int *I) { return; }
+void foo_v2(float *AAA, float *BBB, int *I) { return; }
+void foo_v3(float *AAA, float *BBB, int *I) { return; }
+
+#ifdef OMP51
+// expected-error@+3 {{'adjust_arg' argument 'AAA' used in multiple clauses}}
+#pragma omp declare variant(foo_v1)                          \
+   match(construct={dispatch}, device={arch(arm)})           \
+   adjust_args(need_device_ptr:AAA,BBB) adjust_args(need_device_ptr:AAA)
+
+// expected-error@+3 {{'adjust_arg' argument 'AAA' used in multiple clauses}}
+#pragma omp declare variant(foo_v1)                          \
+   match(construct={dispatch}, device={arch(ppc)}),          \
+   adjust_args(need_device_ptr:AAA) adjust_args(nothing:AAA)
+
+// expected-error@+2 {{use of undeclared identifier 'J'}}
+#pragma omp declare variant(foo_v1)                          \
+   adjust_args(nothing:J)                                    \
+   match(construct={dispatch}, device={arch(x86,x86_64)})
+
+// expected-error@+2 {{expected reference to one of the parameters of function 'foo'}}
+#pragma omp declare variant(foo_v3)                          \
+   adjust_args(nothing:Other)                                \
+   match(construct={dispatch}, device={arch(x86,x86_64)})
+
+// expected-error@+2 {{'adjust_args' clause requires 'dispatch' context selector}}
+#pragma omp declare variant(foo_v3)                          \
+   adjust_args(nothing:BBB) match(construct={target}, device={arch(arm)})
+
+// expected-error@+2 {{'adjust_args' clause requires 'dispatch' context selector}}
+#pragma omp declare variant(foo_v3)                          \
+   adjust_args(nothing:BBB) match(device={arch(ppc)})
+#endif // OMP51
+#ifdef OMP50
+// expected-error@+2 {{expected 'match' clause on 'omp declare variant' directive}}
+#pragma omp declare variant(foo_v1)                            \
+   adjust_args(need_device_ptr:AAA) match(device={arch(arm)})
+#endif // OMP50
+
+void foo(float *AAA, float *BBB, int *I) { return; }
+

clang/test/OpenMP/declare_variant_messages.c

 #pragma omp declare variant(foo) // expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foo) xxx // expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foo) match // expected-error {{expected '(' after 'match'}}
 #pragma omp declare variant(foo) match( // expected-error {{expected ')'}} expected-warning {{expected identifier or string literal describing a context set; set skipped}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}} expected-note {{to match this '('}}
 #pragma omp declare variant(foo) match() // expected-warning {{expected identifier or string literal describing a context set; set skipped}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 #pragma omp declare variant(foo) match(xxx) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 #pragma omp declare variant(foo) match(xxx=) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 #pragma omp declare variant(foo) match(xxx=yyy) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
-#pragma omp declare variant(foo) match(xxx=yyy}) // expected-error {{expected ')'}} expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}} expected-note {{to match this '('}}
+#pragma omp declare variant(foo) match(xxx=yyy}) // expected-error {{expected ')'}} expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}} expected-note {{to match this '('}} expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foo) match(xxx={) // expected-error {{expected ')'}} expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}} expected-note {{to match this '('}}
 #pragma omp declare variant(foo) match(xxx={}) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 #pragma omp declare variant(foo) match(xxx={vvv, vvv}) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
 #pragma omp declare variant(foo) match(xxx={vvv} xxx) // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
-#pragma omp declare variant(foo) match(xxx={vvv}) xxx // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}}
+#pragma omp declare variant(foo) match(xxx={vvv}) xxx // expected-warning {{'xxx' is not a valid context set in a `declare variant`; set ignored}} expected-note {{context set options are: 'construct' 'device' 'implementation' 'user'}} expected-note {{the ignored set spans until here}} expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foo) match(implementation={xxx}) // expected-warning {{'xxx' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foo) match(implementation={vendor}) // expected-warning {{the context selector 'vendor' in context set 'implementation' requires a context property defined in parentheses; selector ignored}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foo) match(implementation={vendor(}) // expected-error {{expected ')'}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foo) match(implementation={vendor()}) // expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}}
 #pragma omp declare variant(foo) match(implementation={vendor(score ibm)}) // expected-error {{expected '(' after 'score'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}}
 #pragma omp declare variant(foo) match(implementation={vendor(score( ibm)}) // expected-error {{use of undeclared identifier 'ibm'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foo) match(implementation={vendor(score(2 ibm)}) // expected-error {{expected ')'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{to match this '('}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foo) match(implementation={vendor(score(foo()) ibm)}) // expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{score expressions in the OpenMP context selector need to be constant; foo() is not and will be ignored}}

clang/test/OpenMP/declare_variant_messages.cpp

 #pragma omp declare variant(foofoo <int>) match(implementation) // expected-warning {{expected '=' after the context set name "implementation"; '=' assumed}} expected-warning {{expected '{' after the '=' that follows the context set name "implementation"; '{' assumed}} expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-warning {{expected '}' after the context selectors for the context set "implementation"; '}' assumed}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation =) // expected-warning {{expected '{' after the '=' that follows the context set name "implementation"; '{' assumed}} expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-warning {{expected '}' after the context selectors for the context set "implementation"; '}' assumed}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = yyy) // expected-warning {{expected '{' after the '=' that follows the context set name "implementation"; '{' assumed}} expected-warning {{'yyy' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-warning {{expected '}' after the context selectors for the context set "implementation"; '}' assumed}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = yyy }) // expected-warning {{expected '{' after the '=' that follows the context set name "implementation"; '{' assumed}} expected-warning {{'yyy' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = {) // expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-warning {{expected '}' after the context selectors for the context set "implementation"; '}' assumed}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = {}) // expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = {vvv, vvv}) // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation = {vvv} implementation) // expected-error {{expected ')'}} expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-note {{to match this '('}}
-#pragma omp declare variant(foofoo <int>) match(implementation = {vvv}) implementation // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
+#pragma omp declare variant(foofoo <int>) match(implementation = {vvv}) implementation // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foofoo <int>) match(implementation={xxx}) // expected-warning {{'xxx' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor}) // expected-warning {{the context selector 'vendor' in context set 'implementation' requires a context property defined in parentheses; selector ignored}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(}) // expected-error {{expected ')'}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor()}) // expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score ibm)}) // expected-error {{expected '(' after 'score'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score( ibm)}) // expected-error {{use of undeclared identifier 'ibm'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(2 ibm)}) // expected-error {{expected ')'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{to match this '('}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(foofoo <int>()) ibm)}) // expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{score expressions in the OpenMP context selector need to be constant; foofoo<int>() is not and will be ignored}}

 #pragma omp declare variant(foofoo <T>) match(implementation = {) // expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-warning {{expected '}' after the context selectors for the context set "implementation"; '}' assumed}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(implementation = {}) // expected-warning {{expected identifier or string literal describing a context selector; selector skipped}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(implementation = {vvv, vvv}) // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(user = {score(<expr>) : condition(<expr>)}) // expected-warning {{'score' is not a valid context selector for the context set 'user'; selector ignored}} expected-note {{context selector options are: 'condition'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(user = {score(<expr>) : condition(<expr>)}) // expected-warning {{'score' is not a valid context selector for the context set 'user'; selector ignored}} expected-note {{context selector options are: 'condition'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(user = {condition(<expr>)}) // expected-error {{expected expression}} expected-error {{use of undeclared identifier 'expr'}} expected-error {{expected expression}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(user = {condition(<expr>)}) // expected-error {{expected expression}} expected-error {{use of undeclared identifier 'expr'}} expected-error {{expected expression}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <T>) match(implementation = {vvv} implementation) // expected-error {{expected ')'}} expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-note {{to match this '('}}
-#pragma omp declare variant(foofoo <T>) match(implementation = {vvv}) xxx // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}}
+#pragma omp declare variant(foofoo <T>) match(implementation = {vvv}) xxx // expected-warning {{'vvv' is not a valid context selector for the context set 'implementation'; selector ignored}} expected-note {{context selector options are: 'vendor' 'extension' 'unified_address' 'unified_shared_memory' 'reverse_offload' 'dynamic_allocators' 'atomic_default_mem_order'}} expected-note {{the ignored selector spans until here}} expected-error {{expected 'match' clause on 'omp declare variant' directive}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score ibm)}) // expected-error {{expected '(' after 'score'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score( ibm)}) // expected-error {{use of undeclared identifier 'ibm'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(C ibm)}) // expected-error {{expected ')'}} expected-error {{expected ')'}} expected-warning {{expected '':'' after the score expression; '':'' assumed}} expected-warning {{expected identifier or string literal describing a context property; property skipped}} expected-note {{to match this '('}} expected-note {{context property options are: 'amd' 'arm' 'bsc' 'cray' 'fujitsu' 'gnu' 'ibm' 'intel' 'llvm' 'pgi' 'ti' 'unknown'}} expected-note {{to match this '('}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(foofoo <int>()) ibm)}) // expected-warning {{expected '':'' after the score expression; '':'' assumed}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(C+5): ibm), vendor(llvm)}) // expected-warning {{the context selector 'vendor' was used already in the same 'omp declare variant' directive; selector ignored}} expected-note {{the previous context selector 'vendor' used here}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(implementation={vendor(score(5): ibm), kind(cpu)}) // expected-warning {{the context selector 'kind' is not valid for the context set 'implementation'; selector ignored}} expected-note {{the context selector 'kind' can be nested in the context set 'device'; try 'match(device={kind(property)})'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(device={xxx}) // expected-warning {{'xxx' is not a valid context selector for the context set 'device'; selector ignored}} expected-note {{context selector options are: 'kind' 'arch' 'isa'}} expected-note {{the ignored selector spans until here}}
 #pragma omp declare variant(foofoo <int>) match(device={kind}) // expected-warning {{the context selector 'kind' in context set 'device' requires a context property defined in parentheses; selector ignored}} expected-note {{the ignored selector spans until here}}

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

 CHECK_SIMPLE_CLAUSE(UsesAllocators, OMPC_uses_allocators)
 CHECK_SIMPLE_CLAUSE(Update, OMPC_update)
 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(AdjustArgs, OMPC_adjust_args)
 
 CHECK_REQ_SCALAR_INT_CLAUSE(Allocator, OMPC_allocator)
 CHECK_REQ_SCALAR_INT_CLAUSE(Grainsize, OMPC_grainsize)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumTasks, OMPC_num_tasks)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumTeams, OMPC_num_teams)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumThreads, OMPC_num_threads)
 CHECK_REQ_SCALAR_INT_CLAUSE(Priority, OMPC_priority)
 CHECK_REQ_SCALAR_INT_CLAUSE(ThreadLimit, OMPC_thread_limit)

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

def OMPC_UseDeviceAddr : Clause<"use_device_addr"> {
   let clangClass = "OMPUseDeviceAddrClause";
 }
 def OMPC_Uniform : Clause<"uniform"> {
   let flangClass = "Name";
   let isValueList = true;
 }
 def OMPC_DeviceType : Clause<"device_type"> {}
 def OMPC_Match : Clause<"match"> {}
+def OMPC_AdjustArgs : Clause<"adjust_args"> { }
 def OMPC_Depobj : Clause<"depobj"> {
   let clangClass = "OMPDepobjClause";
   let isImplicit = true;
 }
 def OMPC_Flush : Clause<"flush"> {
   let clangClass = "OMPFlushClause";
   let isImplicit = true;
 }
def OMP_Allocate : Directive<"allocate"> {
   let allowedClauses = [
     VersionedClause<OMPC_Allocator>
   ];
 }
 def OMP_DeclareVariant : Directive<"declare variant"> {
   let allowedClauses = [
     VersionedClause<OMPC_Match>
   ];
+  let allowedExclusiveClauses = [
+    VersionedClause<OMPC_AdjustArgs, 51>
+  ];
 }
 def OMP_MasterTaskloop : Directive<"master taskloop"> {
   let allowedClauses = [
     VersionedClause<OMPC_If>,
     VersionedClause<OMPC_Shared>,
     VersionedClause<OMPC_Private>,
     VersionedClause<OMPC_FirstPrivate>,
     VersionedClause<OMPC_LastPrivate>,