[OPENMP5.0]Add basic support for declare variant directive.

Added basic support for declare variant directive and its match clause
with user context selector.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@371892 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 59 insertions, 6 deletions

diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index a8bc1421ce..66c40c0e9e 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -201,6 +201,7 @@ def err_invalid_token_after_declarator_suggest_equal : Error<
   "invalid %0 at end of declaration; did you mean '='?">;
 def err_expected_statement : Error<"expected statement">;
 def err_expected_lparen_after : Error<"expected '(' after '%0'">;
+def err_expected_lbrace_after : Error<"expected '{' after '%0'">;
 def err_expected_rparen_after : Error<"expected ')' after '%0'">;
 def err_expected_punc : Error<"expected ')' or ',' after '%0'">;
 def err_expected_less_after : Error<"expected '<' after '%0'">;
@@ -1177,8 +1178,8 @@ def err_omp_expected_identifier_for_critical : Error<
   "expected identifier specifying the name of the 'omp critical' directive">;
 def err_omp_expected_reduction_identifier : Error<
   "expected identifier or one of the following operators: '+', '-', '*', '&', '|', '^', '&&', or '||'">;
-def err_omp_decl_in_declare_simd : Error<
-  "function declaration is expected after 'declare simd' directive">;
+def err_omp_decl_in_declare_simd_variant : Error<
+  "function declaration is expected after 'declare %select{simd|variant}0' directive">;
 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<
@@ -1199,6 +1200,12 @@ 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">;
+def err_omp_declare_variant_no_ctx_selector : Error<
+  "expected context selector in '%0' clause on 'omp declare variant' directive">;
+def err_omp_declare_variant_equal_expected : Error<
+  "expected '=' after '%0' context selector set name on 'omp declare variant' directive">;
 def warn_omp_more_one_device_type_clause : Warning<
   "more than one 'device_type' clause is specified">,
   InGroup<OpenMPClauses>;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 46af14503e..e55095590f 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9213,10 +9213,10 @@ def err_omp_single_copyprivate_with_nowait : Error<
   "the 'copyprivate' clause must not be used with the 'nowait' clause">;
 def note_omp_nowait_clause_here : Note<
   "'nowait' clause is here">;
-def err_omp_single_decl_in_declare_simd : Error<
-  "single declaration is expected after 'declare simd' directive">;
+def err_omp_single_decl_in_declare_simd_variant : Error<
+  "single declaration is expected after 'declare %select{simd|variant}0' directive">;
 def err_omp_function_expected : Error<
-  "'#pragma omp declare simd' can only be applied to functions">;
+  "'#pragma omp declare %select{simd|variant}0' can only be applied to functions">;
 def err_omp_wrong_cancel_region : Error<
   "one of 'for', 'parallel', 'sections' or 'taskgroup' is expected">;
 def err_omp_parent_cancel_region_nowait : Error<
@@ -9408,6 +9408,27 @@ def note_omp_marked_device_type_here : Note<"marked as 'device_type(%0)' here">;
 def warn_omp_declare_target_after_first_use : Warning<
   "declaration marked as declare target after first use, it may lead to incorrect results">,
   InGroup<OpenMPTarget>;
+def err_omp_declare_variant_incompat_attributes : Error<
+  "'#pragma omp declare variant' is not compatible with any target-specific attributes">;
+def err_omp_declare_variant_after_used : Error<
+  "'#pragma omp declare variant' cannot be applied for function after first "
+  "usage">;
+def err_omp_declare_variant_noproto : Error<
+  "function with '#pragma omp declare variant' must have a prototype">;
+def note_omp_declare_variant_specified_here : Note<
+  "'#pragma omp declare variant' for function specified here">;
+def err_omp_declare_variant_doesnt_support : Error<
+  "'#pragma omp declare variant' does not "
+  "support %select{function templates|virtual functions|"
+  "deduced return types|constructors|destructors|deleted functions|"
+  "defaulted functions|constexpr functions|consteval function}0">;
+def err_omp_declare_variant_diff : Error<
+  "function with '#pragma omp declare variant' has a different %select{calling convention"
+  "|return type|constexpr specification|inline specification|storage class|"
+  "linkage}0">;
+def err_omp_declare_variant_incompat_types : Error<
+  "variant in '#pragma omp declare variant' with type %0 is incompatible with type %1"
+  >;
 } // end of OpenMP category
 
 let CategoryName = "Related Result Type Issue" in {
diff --git a/include/clang/Basic/OpenMPKinds.def b/include/clang/Basic/OpenMPKinds.def
index 9a9592a762..05ecc3496f 100644
--- a/include/clang/Basic/OpenMPKinds.def
+++ b/include/clang/Basic/OpenMPKinds.def
@@ -251,6 +251,7 @@ OPENMP_DIRECTIVE_EXT(target_teams_distribute_parallel_for, "target teams distrib
 OPENMP_DIRECTIVE_EXT(target_teams_distribute_parallel_for_simd, "target teams distribute parallel for simd")
 OPENMP_DIRECTIVE_EXT(target_teams_distribute_simd, "target teams distribute simd")
 OPENMP_DIRECTIVE(allocate)
+OPENMP_DIRECTIVE_EXT(declare_variant, "declare variant")
 
 // OpenMP clauses.
 OPENMP_CLAUSE(allocator, OMPAllocatorClause)
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 9e6d0f4e6c..5c0a831db6 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -2834,6 +2834,10 @@ private:
   DeclGroupPtrTy ParseOMPDeclareSimdClauses(DeclGroupPtrTy Ptr,
                                             CachedTokens &Toks,
                                             SourceLocation Loc);
+  /// Parse clauses for '#pragma omp declare variant'.
+  DeclGroupPtrTy ParseOMPDeclareVariantClauses(DeclGroupPtrTy Ptr,
+                                               CachedTokens &Toks,
+                                               SourceLocation Loc);
   /// Parse clauses for '#pragma omp declare target'.
   DeclGroupPtrTy ParseOMPDeclareTargetClauses();
   /// Parse '#pragma omp end declare target'.
@@ -2927,7 +2931,8 @@ public:
   /// Parses simple expression in parens for single-expression clauses of OpenMP
   /// constructs.
   /// \param RLoc Returned location of right paren.
-  ExprResult ParseOpenMPParensExpr(StringRef ClauseName, SourceLocation &RLoc);
+  ExprResult ParseOpenMPParensExpr(StringRef ClauseName, SourceLocation &RLoc,
+                                   bool IsAddressOfOperand = false);
 
   /// Data used for parsing list of variables in OpenMP clauses.
   struct OpenMPVarListDataTy {
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 59b1d9c3e4..59fc120b7f 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -9090,6 +9090,15 @@ private:
                                      SourceRange SrcRange = SourceRange());
 
 public:
+  /// Checks if the variant/multiversion functions are compatible.
+  bool areMultiversionVariantFunctionsCompatible(
+      const FunctionDecl *OldFD, const FunctionDecl *NewFD,
+      const PartialDiagnostic &NoProtoDiagID,
+      const PartialDiagnosticAt &NoteCausedDiagIDAt,
+      const PartialDiagnosticAt &NoSupportDiagIDAt,
+      const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
+      bool ConstexprSupported);
+
   /// Function tries to capture lambda's captured variables in the OpenMP region
   /// before the original lambda is captured.
   void tryCaptureOpenMPLambdas(ValueDecl *V);
@@ -9514,6 +9523,16 @@ public:
       ArrayRef<Expr *> Alignments, ArrayRef<Expr *> Linears,
       ArrayRef<unsigned> LinModifiers, ArrayRef<Expr *> Steps, SourceRange SR);
 
+  /// Called on well-formed '\#pragma omp declare variant' after parsing of
+  /// the associated method/function.
+  /// \param DG 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.
+  DeclGroupPtrTy ActOnOpenMPDeclareVariantDirective(DeclGroupPtrTy DG,
+                                                    Expr *VariantRef,
+                                                    SourceRange SR);
+
   OMPClause *ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind,
                                          Expr *Expr,
                                          SourceLocation StartLoc,