1 files changed, 120 insertions, 6 deletions

diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 6bd96051f9e..293660ec4cd 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -42,6 +42,7 @@ enum OpenMPDirectiveKindEx {
   OMPD_teams_distribute_parallel,
   OMPD_target_teams_distribute_parallel,
   OMPD_mapper,
+  OMPD_variant,
 };
 
 class DeclDirectiveListParserHelper final {
@@ -80,6 +81,7 @@ static unsigned getOpenMPDirectiveKindEx(StringRef S) {
       .Case("reduction", OMPD_reduction)
       .Case("update", OMPD_update)
       .Case("mapper", OMPD_mapper)
+      .Case("variant", OMPD_variant)
       .Default(OMPD_unknown);
 }
 
@@ -93,6 +95,7 @@ static OpenMPDirectiveKind parseOpenMPDirectiveKind(Parser &P) {
       {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_distribute, OMPD_parallel, OMPD_distribute_parallel},
       {OMPD_distribute_parallel, OMPD_for, OMPD_distribute_parallel_for},
       {OMPD_distribute_parallel_for, OMPD_simd,
@@ -752,6 +755,7 @@ Parser::ParseOMPDeclareSimdClauses(Parser::DeclGroupPtrTy Ptr,
                       /*IsReinject*/ true);
   // Consume the previously pushed token.
   ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
+  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
 
   FNContextRAII FnContext(*this, Ptr);
   OMPDeclareSimdDeclAttr::BranchStateTy BS =
@@ -782,6 +786,107 @@ Parser::ParseOMPDeclareSimdClauses(Parser::DeclGroupPtrTy Ptr,
       LinModifiers, Steps, SourceRange(Loc, EndLoc));
 }
 
+/// Parses clauses for 'declare variant' directive.
+/// clause:
+/// 'match' '('
+/// <selector_set_name> '=' '{' <context_selectors> '}'
+/// ')'
+static bool parseDeclareVariantClause(Parser &P) {
+  Token Tok = P.getCurToken();
+  // Parse 'match'.
+  if (!Tok.is(tok::identifier) ||
+      P.getPreprocessor().getSpelling(Tok).compare("match")) {
+    P.Diag(Tok.getLocation(), diag::err_omp_declare_variant_wrong_clause)
+        << "match";
+    while (!P.SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch))
+      ;
+    return true;
+  }
+  (void)P.ConsumeToken();
+  // Parse '('.
+  BalancedDelimiterTracker T(P, tok::l_paren, tok::annot_pragma_openmp_end);
+  if (T.expectAndConsume(diag::err_expected_lparen_after, "match"))
+    return true;
+  // Parse inner context selector.
+  Tok = P.getCurToken();
+  if (!Tok.is(tok::identifier)) {
+    P.Diag(Tok.getLocation(), diag::err_omp_declare_variant_no_ctx_selector)
+        << "match";
+    return true;
+  }
+  SmallString<16> Buffer;
+  StringRef CtxSelectorName = P.getPreprocessor().getSpelling(Tok, Buffer);
+  // Parse '='.
+  (void)P.ConsumeToken();
+  Tok = P.getCurToken();
+  if (Tok.isNot(tok::equal)) {
+    P.Diag(Tok.getLocation(), diag::err_omp_declare_variant_equal_expected)
+        << CtxSelectorName;
+    return true;
+  }
+  (void)P.ConsumeToken();
+  // Unknown selector - just ignore it completely.
+  {
+    // Parse '{'.
+    BalancedDelimiterTracker TBr(P, tok::l_brace, tok::annot_pragma_openmp_end);
+    if (TBr.expectAndConsume(diag::err_expected_lbrace_after, "="))
+      return true;
+    while (!P.SkipUntil(tok::r_brace, tok::r_paren,
+                        tok::annot_pragma_openmp_end, Parser::StopBeforeMatch))
+      ;
+    // Parse '}'.
+    (void)TBr.consumeClose();
+  }
+  // Parse ')'.
+  (void)T.consumeClose();
+  // TBD: add parsing of known context selectors.
+  return false;
+}
+
+/// Parse clauses for '#pragma omp declare variant ( variant-func-id ) clause'.
+Parser::DeclGroupPtrTy
+Parser::ParseOMPDeclareVariantClauses(Parser::DeclGroupPtrTy Ptr,
+                                      CachedTokens &Toks, SourceLocation Loc) {
+  PP.EnterToken(Tok, /*IsReinject*/ true);
+  PP.EnterTokenStream(Toks, /*DisableMacroExpansion=*/true,
+                      /*IsReinject*/ true);
+  // Consume the previously pushed token.
+  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
+  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
+
+  FNContextRAII FnContext(*this, Ptr);
+  // Parse function declaration id.
+  SourceLocation RLoc;
+  // Parse with IsAddressOfOperand set to true to parse methods as DeclRefExprs
+  // instead of MemberExprs.
+  ExprResult AssociatedFunction =
+      ParseOpenMPParensExpr(getOpenMPDirectiveName(OMPD_declare_variant), RLoc,
+                            /*IsAddressOfOperand=*/true);
+  if (!AssociatedFunction.isUsable()) {
+    if (!Tok.is(tok::annot_pragma_openmp_end))
+      while (!SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch))
+        ;
+    // Skip the last annot_pragma_openmp_end.
+    (void)ConsumeAnnotationToken();
+    return Ptr;
+  }
+
+  bool IsError = parseDeclareVariantClause(*this);
+  // Need to check for extra tokens.
+  if (Tok.isNot(tok::annot_pragma_openmp_end)) {
+    Diag(Tok, diag::warn_omp_extra_tokens_at_eol)
+        << getOpenMPDirectiveName(OMPD_declare_variant);
+    while (Tok.isNot(tok::annot_pragma_openmp_end))
+      ConsumeAnyToken();
+  }
+  // Skip the last annot_pragma_openmp_end.
+  SourceLocation EndLoc = ConsumeAnnotationToken();
+  if (IsError)
+    return Ptr;
+  return Actions.ActOnOpenMPDeclareVariantDirective(
+      Ptr, AssociatedFunction.get(), SourceRange(Loc, EndLoc));
+}
+
 /// Parsing of simple OpenMP clauses like 'default' or 'proc_bind'.
 ///
 ///    default-clause:
@@ -1103,13 +1208,15 @@ Parser::DeclGroupPtrTy Parser::ParseOpenMPDeclarativeDirectiveWithExtDecl(
     }
     break;
   }
+  case OMPD_declare_variant:
   case OMPD_declare_simd: {
     // The syntax is:
-    // { #pragma omp declare simd }
+    // { #pragma omp declare {simd|variant} }
     // <function-declaration-or-definition>
     //
-    ConsumeToken();
     CachedTokens Toks;
+    Toks.push_back(Tok);
+    ConsumeToken();
     while(Tok.isNot(tok::annot_pragma_openmp_end)) {
       Toks.push_back(Tok);
       ConsumeAnyToken();
@@ -1133,10 +1240,15 @@ Parser::DeclGroupPtrTy Parser::ParseOpenMPDeclarativeDirectiveWithExtDecl(
       }
     }
     if (!Ptr) {
-      Diag(Loc, diag::err_omp_decl_in_declare_simd);
+      Diag(Loc, diag::err_omp_decl_in_declare_simd_variant)
+          << (DKind == OMPD_declare_simd ? 0 : 1);
       return DeclGroupPtrTy();
     }
-    return ParseOMPDeclareSimdClauses(Ptr, Toks, Loc);
+    if (DKind == OMPD_declare_simd)
+      return ParseOMPDeclareSimdClauses(Ptr, Toks, Loc);
+    assert(DKind == OMPD_declare_variant &&
+           "Expected declare variant directive only");
+    return ParseOMPDeclareVariantClauses(Ptr, Toks, Loc);
   }
   case OMPD_declare_target: {
     SourceLocation DTLoc = ConsumeAnyToken();
@@ -1572,6 +1684,7 @@ Parser::ParseOpenMPDeclarativeOrExecutableDirective(ParsedStmtContext StmtCtx) {
   case OMPD_declare_target:
   case OMPD_end_declare_target:
   case OMPD_requires:
+  case OMPD_declare_variant:
     Diag(Tok, diag::err_omp_unexpected_directive)
         << 1 << getOpenMPDirectiveName(DKind);
     SkipUntil(tok::annot_pragma_openmp_end);
@@ -1831,14 +1944,15 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
 /// constructs.
 /// \param RLoc Returned location of right paren.
 ExprResult Parser::ParseOpenMPParensExpr(StringRef ClauseName,
-                                         SourceLocation &RLoc) {
+                                         SourceLocation &RLoc,
+                                         bool IsAddressOfOperand) {
   BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
   if (T.expectAndConsume(diag::err_expected_lparen_after, ClauseName.data()))
     return ExprError();
 
   SourceLocation ELoc = Tok.getLocation();
   ExprResult LHS(ParseCastExpression(
-      /*isUnaryExpression=*/false, /*isAddressOfOperand=*/false, NotTypeCast));
+      /*isUnaryExpression=*/false, IsAddressOfOperand, NotTypeCast));
   ExprResult Val(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
   Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);