[clang][OpenMP] Issue a warning when parsing future directive spelling

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1530,9 +1530,11 @@ def OpenMPPre51Compat : DiagGroup<"pre-openmp-51-compat">;
 def OpenMP51Ext : DiagGroup<"openmp-51-extensions">;
 def OpenMPExtensions : DiagGroup<"openmp-extensions">;
 def OpenMPTargetException : DiagGroup<"openmp-target-exception">;
+def OpenMPFuture : DiagGroup<"openmp-future">;
 def OpenMP : DiagGroup<"openmp", [
     SourceUsesOpenMP, OpenMPClauses, OpenMPLoopForm, OpenMPTarget,
-    OpenMPMapping, OpenMP51Ext, OpenMPExtensions, OpenMPTargetException
+    OpenMPMapping, OpenMP51Ext, OpenMPExtensions, OpenMPTargetException,
+    OpenMPFuture
   ]>;
 
 // OpenACC warnings.

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -1488,6 +1488,9 @@ def err_omp_multiple_step_or_linear_modifier : Error<
   "multiple %select{'step size'|'linear modifier'}0 found in linear clause">;
 def err_omp_deprecate_old_syntax: Error<
   "old syntax '%0' on '%1' clause was deprecated, use new syntax '%2'">;
+def warn_omp_future_directive_spelling: Warning<
+  "directive spelling '%0' is introduced in a later OpenMP version">,
+  InGroup<OpenMPFuture>;
 def warn_pragma_expected_colon_r_paren : Warning<
   "missing ':' or ')' after %0 - ignoring">, InGroup<IgnoredPragmas>;
 def err_omp_unknown_directive : Error<

clang/lib/Parse/ParseOpenMP.cpp

@@ -25,6 +25,7 @@
 #include "clang/Sema/SemaOpenMP.h"
 #include "llvm/ADT/SmallBitVector.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/Frontend/OpenMP/DirectiveNameParser.h"
 #include "llvm/Frontend/OpenMP/OMPAssume.h"
 #include "llvm/Frontend/OpenMP/OMPContext.h"
 #include <optional>
@@ -37,48 +38,6 @@ using namespace llvm::omp;
 //===----------------------------------------------------------------------===//
 
 namespace {
-enum OpenMPDirectiveKindEx {
-  OMPD_cancellation = llvm::omp::Directive_enumSize + 1,
-  OMPD_data,
-  OMPD_declare,
-  OMPD_end,
-  OMPD_end_declare,
-  OMPD_enter,
-  OMPD_exit,
-  OMPD_point,
-  OMPD_reduction,
-  OMPD_target_enter,
-  OMPD_target_exit,
-  OMPD_update,
-  OMPD_distribute_parallel,
-  OMPD_teams_distribute_parallel,
-  OMPD_target_teams_distribute_parallel,
-  OMPD_mapper,
-  OMPD_variant,
-  OMPD_begin,
-  OMPD_begin_declare,
-};
-
-// Helper to unify the enum class OpenMPDirectiveKind with its extension
-// the OpenMPDirectiveKindEx enum which allows to use them together as if they
-// are unsigned values.
-struct OpenMPDirectiveKindExWrapper {
-  OpenMPDirectiveKindExWrapper(unsigned Value) : Value(Value) {}
-  OpenMPDirectiveKindExWrapper(OpenMPDirectiveKind DK) : Value(unsigned(DK)) {}
-  bool operator==(OpenMPDirectiveKindExWrapper V) const {
-    return Value == V.Value;
-  }
-  bool operator!=(OpenMPDirectiveKindExWrapper V) const {
-    return Value != V.Value;
-  }
-  bool operator==(OpenMPDirectiveKind V) const { return Value == unsigned(V); }
-  bool operator!=(OpenMPDirectiveKind V) const { return Value != unsigned(V); }
-  bool operator<(OpenMPDirectiveKind V) const { return Value < unsigned(V); }
-  operator unsigned() const { return Value; }
-  operator OpenMPDirectiveKind() const { return OpenMPDirectiveKind(Value); }
-  unsigned Value;
-};
-
 class DeclDirectiveListParserHelper final {
   SmallVector<Expr *, 4> Identifiers;
   Parser *P;
@@ -97,130 +56,52 @@ class DeclDirectiveListParserHelper final {
 };
 } // namespace
 
-// Map token string to extended OMP token kind that are
-// OpenMPDirectiveKind + OpenMPDirectiveKindEx.
-static unsigned getOpenMPDirectiveKindEx(StringRef S) {
-  OpenMPDirectiveKindExWrapper DKind = getOpenMPDirectiveKind(S);
-  if (DKind != OMPD_unknown)
-    return DKind;
-
-  return llvm::StringSwitch<OpenMPDirectiveKindExWrapper>(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)
-      .Case("update", OMPD_update)
-      .Case("mapper", OMPD_mapper)
-      .Case("variant", OMPD_variant)
-      .Case("begin", OMPD_begin)
-      .Default(OMPD_unknown);
+static OpenMPDirectiveKind checkOpenMPDirectiveName(Parser &P,
+                                                    SourceLocation Loc,
+                                                    OpenMPDirectiveKind Kind,
+                                                    StringRef Name) {
+  unsigned Version = P.getLangOpts().OpenMP;
+  auto [D, VR] = getOpenMPDirectiveKindAndVersions(Name);
+  assert(D == Kind && "Directive kind mismatch");
+  // Ignore the case Version > VR.Max: In OpenMP 6.0 all prior spellings
+  // are explicitly allowed.
+  if (Version < VR.Min)
+    P.Diag(Loc, diag::warn_omp_future_directive_spelling) << Name;
+
+  return Kind;
 }
 
-static OpenMPDirectiveKindExWrapper 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 OpenMPDirectiveKindExWrapper F[][3] = {
-      {OMPD_begin, OMPD_declare, OMPD_begin_declare},
-      {OMPD_begin, OMPD_assumes, OMPD_begin_assumes},
-      {OMPD_end, OMPD_declare, OMPD_end_declare},
-      {OMPD_end, OMPD_assumes, OMPD_end_assumes},
-      {OMPD_cancellation, OMPD_point, OMPD_cancellation_point},
-      {OMPD_declare, OMPD_reduction, OMPD_declare_reduction},
-      {OMPD_declare, OMPD_mapper, OMPD_declare_mapper},
-      {OMPD_declare, OMPD_simd, OMPD_declare_simd},
-      {OMPD_declare, OMPD_target, OMPD_declare_target},
-      {OMPD_declare, OMPD_variant, OMPD_declare_variant},
-      {OMPD_begin_declare, OMPD_target, OMPD_begin_declare_target},
-      {OMPD_begin_declare, OMPD_variant, OMPD_begin_declare_variant},
-      {OMPD_end_declare, OMPD_variant, OMPD_end_declare_variant},
-      {OMPD_distribute, OMPD_parallel, OMPD_distribute_parallel},
-      {OMPD_distribute_parallel, OMPD_for, OMPD_distribute_parallel_for},
-      {OMPD_distribute_parallel_for, OMPD_simd,
-       OMPD_distribute_parallel_for_simd},
-      {OMPD_distribute, OMPD_simd, OMPD_distribute_simd},
-      {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, OMPD_update, OMPD_target_update},
-      {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},
-      {OMPD_parallel, OMPD_loop, OMPD_parallel_loop},
-      {OMPD_parallel, OMPD_sections, OMPD_parallel_sections},
-      {OMPD_taskloop, OMPD_simd, OMPD_taskloop_simd},
-      {OMPD_target, OMPD_parallel, OMPD_target_parallel},
-      {OMPD_target, OMPD_simd, OMPD_target_simd},
-      {OMPD_target_parallel, OMPD_loop, OMPD_target_parallel_loop},
-      {OMPD_target_parallel, OMPD_for, OMPD_target_parallel_for},
-      {OMPD_target_parallel_for, OMPD_simd, OMPD_target_parallel_for_simd},
-      {OMPD_teams, OMPD_distribute, OMPD_teams_distribute},
-      {OMPD_teams_distribute, OMPD_simd, OMPD_teams_distribute_simd},
-      {OMPD_teams_distribute, OMPD_parallel, OMPD_teams_distribute_parallel},
-      {OMPD_teams_distribute_parallel, OMPD_for,
-       OMPD_teams_distribute_parallel_for},
-      {OMPD_teams_distribute_parallel_for, OMPD_simd,
-       OMPD_teams_distribute_parallel_for_simd},
-      {OMPD_teams, OMPD_loop, OMPD_teams_loop},
-      {OMPD_target, OMPD_teams, OMPD_target_teams},
-      {OMPD_target_teams, OMPD_distribute, OMPD_target_teams_distribute},
-      {OMPD_target_teams, OMPD_loop, OMPD_target_teams_loop},
-      {OMPD_target_teams_distribute, OMPD_parallel,
-       OMPD_target_teams_distribute_parallel},
-      {OMPD_target_teams_distribute, OMPD_simd,
-       OMPD_target_teams_distribute_simd},
-      {OMPD_target_teams_distribute_parallel, OMPD_for,
-       OMPD_target_teams_distribute_parallel_for},
-      {OMPD_target_teams_distribute_parallel_for, OMPD_simd,
-       OMPD_target_teams_distribute_parallel_for_simd},
-      {OMPD_master, OMPD_taskloop, OMPD_master_taskloop},
-      {OMPD_masked, OMPD_taskloop, OMPD_masked_taskloop},
-      {OMPD_master_taskloop, OMPD_simd, OMPD_master_taskloop_simd},
-      {OMPD_masked_taskloop, OMPD_simd, OMPD_masked_taskloop_simd},
-      {OMPD_parallel, OMPD_master, OMPD_parallel_master},
-      {OMPD_parallel, OMPD_masked, OMPD_parallel_masked},
-      {OMPD_parallel_master, OMPD_taskloop, OMPD_parallel_master_taskloop},
-      {OMPD_parallel_masked, OMPD_taskloop, OMPD_parallel_masked_taskloop},
-      {OMPD_parallel_master_taskloop, OMPD_simd,
-       OMPD_parallel_master_taskloop_simd},
-      {OMPD_parallel_masked_taskloop, OMPD_simd,
-       OMPD_parallel_masked_taskloop_simd}};
-  enum { CancellationPoint = 0, DeclareReduction = 1, TargetData = 2 };
+static OpenMPDirectiveKind parseOpenMPDirectiveKind(Parser &P) {
+  static const DirectiveNameParser DirParser;
+
+  const DirectiveNameParser::State *S = DirParser.initial();
+
   Token Tok = P.getCurToken();
-  OpenMPDirectiveKindExWrapper DKind =
-      Tok.isAnnotation()
-          ? static_cast<unsigned>(OMPD_unknown)
-          : getOpenMPDirectiveKindEx(P.getPreprocessor().getSpelling(Tok));
-  if (DKind == OMPD_unknown)
+  if (Tok.isAnnotation())
     return OMPD_unknown;
 
-  for (const auto &I : F) {
-    if (DKind != I[0])
-      continue;
+  std::string Concat = P.getPreprocessor().getSpelling(Tok);
+  SourceLocation Loc = Tok.getLocation();
 
-    Tok = P.getPreprocessor().LookAhead(0);
-    OpenMPDirectiveKindExWrapper SDKind =
-        Tok.isAnnotation()
-            ? static_cast<unsigned>(OMPD_unknown)
-            : getOpenMPDirectiveKindEx(P.getPreprocessor().getSpelling(Tok));
-    if (SDKind == OMPD_unknown)
-      continue;
+  S = DirParser.consume(S, Concat);
+  if (S == nullptr)
+    return OMPD_unknown;
 
-    if (SDKind == I[1]) {
+  while (!Tok.isAnnotation()) {
+    OpenMPDirectiveKind DKind = S->Value;
+    Tok = P.getPreprocessor().LookAhead(0);
+    if (!Tok.isAnnotation()) {
+      std::string TS = P.getPreprocessor().getSpelling(Tok);
+      S = DirParser.consume(S, TS);
+      if (S == nullptr)
+        return checkOpenMPDirectiveName(P, Loc, DKind, Concat);
+      Concat += ' ' + TS;
       P.ConsumeToken();
-      DKind = I[2];
     }
   }
-  return unsigned(DKind) < llvm::omp::Directive_enumSize
-             ? static_cast<OpenMPDirectiveKind>(DKind)
-             : OMPD_unknown;
+
+  assert(S && "Should have exited early");
+  return checkOpenMPDirectiveName(P, Loc, S->Value, Concat);
 }
 
 static DeclarationName parseOpenMPReductionId(Parser &P) {
@@ -2629,10 +2510,6 @@ StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
     Diag(Tok, diag::err_omp_unknown_directive);
     return StmtError();
   }
-  if (!(getDirectiveLanguages(DKind) & SourceLanguage::C)) {
-    // Treat directives that are not allowed in C/C++ as unknown.
-    DKind = OMPD_unknown;
-  }
 
   StmtResult Directive = StmtError();
 
@@ -4014,7 +3891,7 @@ OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPDirectiveKind DKind,
     KLoc.push_back(Tok.getLocation());
     TentativeParsingAction TPA(*this);
     auto DK = parseOpenMPDirectiveKind(*this);
-    Arg.push_back(DK);
+    Arg.push_back(static_cast<unsigned>(DK));
     if (DK != OMPD_unknown) {
       ConsumeToken();
       if (Tok.is(tok::colon) && getLangOpts().OpenMP > 40) {

clang/test/OpenMP/openmp-6-future-spellings.cpp

@@ -0,0 +1,55 @@
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=52 -ferror-limit 100 -o - %s
+
+// expected-warning@+1 {{directive spelling 'begin declare_target' is introduced in a later OpenMP version}}
+#pragma omp begin declare_target
+void f0();
+// expected-warning@+1 {{directive spelling 'end declare_target' is introduced in a later OpenMP version}}
+#pragma omp end declare_target
+
+// expected-warning@+1 {{directive spelling 'begin declare_variant' is introduced in a later OpenMP version}}
+#pragma omp begin declare_variant match(user={condition(true)})
+void f1();
+// expected-warning@+1 {{directive spelling 'end declare_variant' is introduced in a later OpenMP version}}
+#pragma omp end declare_variant
+
+int x;
+// expected-warning@+1 {{directive spelling 'declare_target' is introduced in a later OpenMP version}}
+#pragma omp declare_target(x)
+
+struct A {
+  int x, y;
+};
+// expected-warning@+1 {{directive spelling 'declare_mapper' is introduced in a later OpenMP version}}
+#pragma omp declare_mapper(mymapper: A a) map(tofrom:a.x, a.y)
+A add(A, A);
+// expected-warning@+1 {{directive spelling 'declare_reduction' is introduced in a later OpenMP version}}
+#pragma omp declare_reduction(+: A: omp_out = add(omp_in, omp_out))
+
+// expected-warning@+1 {{directive spelling 'declare_simd' is introduced in a later OpenMP version}}
+#pragma omp declare_simd
+void f2();
+
+void g3();
+// expected-warning@+1 {{directive spelling 'declare_variant' is introduced in a later OpenMP version}}
+#pragma omp declare_variant(g3) match(user={condition(true)})
+void f3() {}
+
+void fred() {
+  #pragma omp parallel
+  {
+    // expected-warning@+1 {{directive spelling 'cancellation_point' is introduced in a later OpenMP version}}
+    #pragma omp cancellation_point parallel
+  }
+
+  // expected-warning@+1 {{directive spelling 'target_data' is introduced in a later OpenMP version}}
+  #pragma omp target_data map(tofrom: x)
+  {}
+
+  // expected-warning@+1 {{directive spelling 'target_enter_data' is introduced in a later OpenMP version}}
+  #pragma omp target_enter_data map(to: x)
+  // expected-warning@+1 {{directive spelling 'target_exit_data' is introduced in a later OpenMP version}}
+  #pragma omp target_exit_data map(from: x)
+  // expected-warning@+1 {{directive spelling 'target_update' is introduced in a later OpenMP version}}
+  #pragma omp target_update from(x)
+}
+