[OpenMP 5.0] Parsing/sema support for "omp declare mapper" directive.

This patch implements parsing and sema for "omp declare mapper"
directive. User defined mapper, i.e., declare mapper directive, is a new
feature in OpenMP 5.0. It is introduced to extend existing map clauses
for the purpose of simplifying the copy of complex data structures
between host and device (i.e., deep copy). An example is shown below:

    struct S {  int len;  int *d; };
    #pragma omp declare mapper(struct S s) map(s, s.d[0:s.len]) // Memory region that d points to is also mapped using this mapper.

Contributed-by: Lingda Li <lildmh@gmail.com>

Differential Revision: https://reviews.llvm.org/D56326

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@352906 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 170 insertions, 1 deletions

diff --git a/lib/Parse/ParseOpenMP.cpp b/lib/Parse/ParseOpenMP.cpp
index 2308e6e3da..5b8670e928 100644
--- a/lib/Parse/ParseOpenMP.cpp
+++ b/lib/Parse/ParseOpenMP.cpp
@@ -40,7 +40,8 @@ enum OpenMPDirectiveKindEx {
   OMPD_update,
   OMPD_distribute_parallel,
   OMPD_teams_distribute_parallel,
-  OMPD_target_teams_distribute_parallel
+  OMPD_target_teams_distribute_parallel,
+  OMPD_mapper,
 };
 
 class ThreadprivateListParserHelper final {
@@ -76,6 +77,7 @@ static unsigned getOpenMPDirectiveKindEx(StringRef S) {
       .Case("point", OMPD_point)
       .Case("reduction", OMPD_reduction)
       .Case("update", OMPD_update)
+      .Case("mapper", OMPD_mapper)
       .Default(OMPD_unknown);
 }
 
@@ -86,6 +88,7 @@ static OpenMPDirectiveKind parseOpenMPDirectiveKind(Parser &P) {
   static const unsigned F[][3] = {
       {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_distribute, OMPD_parallel, OMPD_distribute_parallel},
@@ -469,6 +472,141 @@ void Parser::ParseOpenMPReductionInitializerForDecl(VarDecl *OmpPrivParm) {
   }
 }
 
+/// Parses 'omp declare mapper' directive.
+///
+///       declare-mapper-directive:
+///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifier> ':']
+///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+///         annot_pragma_openmp_end
+/// <mapper-identifier> and <var> are base language identifiers.
+///
+Parser::DeclGroupPtrTy
+Parser::ParseOpenMPDeclareMapperDirective(AccessSpecifier AS) {
+  bool IsCorrect = true;
+  // Parse '('
+  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
+  if (T.expectAndConsume(diag::err_expected_lparen_after,
+                         getOpenMPDirectiveName(OMPD_declare_mapper))) {
+    SkipUntil(tok::annot_pragma_openmp_end, StopBeforeMatch);
+    return DeclGroupPtrTy();
+  }
+
+  // Parse <mapper-identifier>
+  auto &DeclNames = Actions.getASTContext().DeclarationNames;
+  DeclarationName MapperId;
+  if (PP.LookAhead(0).is(tok::colon)) {
+    if (Tok.isNot(tok::identifier) && Tok.isNot(tok::kw_default)) {
+      Diag(Tok.getLocation(), diag::err_omp_mapper_illegal_identifier);
+      IsCorrect = false;
+    } else {
+      MapperId = DeclNames.getIdentifier(Tok.getIdentifierInfo());
+    }
+    ConsumeToken();
+    // Consume ':'.
+    ExpectAndConsume(tok::colon);
+  } else {
+    // If no mapper identifier is provided, its name is "default" by default
+    MapperId =
+        DeclNames.getIdentifier(&Actions.getASTContext().Idents.get("default"));
+  }
+
+  if (!IsCorrect && Tok.is(tok::annot_pragma_openmp_end))
+    return DeclGroupPtrTy();
+
+  // Parse <type> <var>
+  DeclarationName VName;
+  QualType MapperType;
+  SourceRange Range;
+  TypeResult ParsedType = parseOpenMPDeclareMapperVarDecl(Range, VName, AS);
+  if (ParsedType.isUsable())
+    MapperType =
+        Actions.ActOnOpenMPDeclareMapperType(Range.getBegin(), ParsedType);
+  if (MapperType.isNull())
+    IsCorrect = false;
+  if (!IsCorrect) {
+    SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch);
+    return DeclGroupPtrTy();
+  }
+
+  // Consume ')'.
+  IsCorrect &= !T.consumeClose();
+  if (!IsCorrect) {
+    SkipUntil(tok::annot_pragma_openmp_end, Parser::StopBeforeMatch);
+    return DeclGroupPtrTy();
+  }
+
+  // Enter scope.
+  OMPDeclareMapperDecl *DMD = Actions.ActOnOpenMPDeclareMapperDirectiveStart(
+      getCurScope(), Actions.getCurLexicalContext(), MapperId, MapperType,
+      Range.getBegin(), VName, AS);
+  DeclarationNameInfo DirName;
+  SourceLocation Loc = Tok.getLocation();
+  unsigned ScopeFlags = Scope::FnScope | Scope::DeclScope |
+                        Scope::CompoundStmtScope | Scope::OpenMPDirectiveScope;
+  ParseScope OMPDirectiveScope(this, ScopeFlags);
+  Actions.StartOpenMPDSABlock(OMPD_declare_mapper, DirName, getCurScope(), Loc);
+
+  // Add the mapper variable declaration.
+  Actions.ActOnOpenMPDeclareMapperDirectiveVarDecl(
+      DMD, getCurScope(), MapperType, Range.getBegin(), VName);
+
+  // Parse map clauses.
+  SmallVector<OMPClause *, 6> Clauses;
+  while (Tok.isNot(tok::annot_pragma_openmp_end)) {
+    OpenMPClauseKind CKind = Tok.isAnnotation()
+                                 ? OMPC_unknown
+                                 : getOpenMPClauseKind(PP.getSpelling(Tok));
+    Actions.StartOpenMPClause(CKind);
+    OMPClause *Clause =
+        ParseOpenMPClause(OMPD_declare_mapper, CKind, Clauses.size() == 0);
+    if (Clause)
+      Clauses.push_back(Clause);
+    else
+      IsCorrect = false;
+    // Skip ',' if any.
+    if (Tok.is(tok::comma))
+      ConsumeToken();
+    Actions.EndOpenMPClause();
+  }
+  if (Clauses.empty()) {
+    Diag(Tok, diag::err_omp_expected_clause)
+        << getOpenMPDirectiveName(OMPD_declare_mapper);
+    IsCorrect = false;
+  }
+
+  // Exit scope.
+  Actions.EndOpenMPDSABlock(nullptr);
+  OMPDirectiveScope.Exit();
+
+  DeclGroupPtrTy DGP =
+      Actions.ActOnOpenMPDeclareMapperDirectiveEnd(DMD, getCurScope(), Clauses);
+  if (!IsCorrect)
+    return DeclGroupPtrTy();
+  return DGP;
+}
+
+TypeResult Parser::parseOpenMPDeclareMapperVarDecl(SourceRange &Range,
+                                                   DeclarationName &Name,
+                                                   AccessSpecifier AS) {
+  // Parse the common declaration-specifiers piece.
+  Parser::DeclSpecContext DSC = Parser::DeclSpecContext::DSC_type_specifier;
+  DeclSpec DS(AttrFactory);
+  ParseSpecifierQualifierList(DS, AS, DSC);
+
+  // Parse the declarator.
+  DeclaratorContext Context = DeclaratorContext::PrototypeContext;
+  Declarator DeclaratorInfo(DS, Context);
+  ParseDeclarator(DeclaratorInfo);
+  Range = DeclaratorInfo.getSourceRange();
+  if (DeclaratorInfo.getIdentifier() == nullptr) {
+    Diag(Tok.getLocation(), diag::err_omp_mapper_expected_declarator);
+    return true;
+  }
+  Name = Actions.GetNameForDeclarator(DeclaratorInfo).getName();
+
+  return Actions.ActOnOpenMPDeclareMapperVarDecl(getCurScope(), DeclaratorInfo);
+}
+
 namespace {
 /// RAII that recreates function context for correct parsing of clauses of
 /// 'declare simd' construct.
@@ -707,6 +845,11 @@ void Parser::ParseOMPEndDeclareTargetDirective(OpenMPDirectiveKind DKind,
 ///        annot_pragma_openmp 'declare' 'reduction' [...]
 ///        annot_pragma_openmp_end
 ///
+///       declare-mapper-directive:
+///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
+///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+///         annot_pragma_openmp_end
+///
 ///       declare-simd-directive:
 ///         annot_pragma_openmp 'declare simd' {<clause> [,]}
 ///         annot_pragma_openmp_end
@@ -800,6 +943,15 @@ Parser::DeclGroupPtrTy Parser::ParseOpenMPDeclarativeDirectiveWithExtDecl(
       return Res;
     }
     break;
+  case OMPD_declare_mapper: {
+    ConsumeToken();
+    if (DeclGroupPtrTy Res = ParseOpenMPDeclareMapperDirective(AS)) {
+      // Skip the last annot_pragma_openmp_end.
+      ConsumeAnnotationToken();
+      return Res;
+    }
+    break;
+  }
   case OMPD_declare_simd: {
     // The syntax is:
     // { #pragma omp declare simd }
@@ -954,6 +1106,11 @@ Parser::DeclGroupPtrTy Parser::ParseOpenMPDeclarativeDirectiveWithExtDecl(
 ///         ('omp_priv' '=' <expression>|<function_call>) ')']
 ///         annot_pragma_openmp_end
 ///
+///       declare-mapper-directive:
+///         annot_pragma_openmp 'declare' 'mapper' '(' [<mapper-identifer> ':']
+///         <type> <var> ')' [<clause>[[,] <clause>] ... ]
+///         annot_pragma_openmp_end
+///
 ///       executable-directive:
 ///         annot_pragma_openmp 'parallel' | 'simd' | 'for' | 'sections' |
 ///         'section' | 'single' | 'master' | 'critical' [ '(' <name> ')' ] |
@@ -1034,6 +1191,18 @@ StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
       SkipUntil(tok::annot_pragma_openmp_end);
     }
     break;
+  case OMPD_declare_mapper: {
+    ConsumeToken();
+    if (DeclGroupPtrTy Res =
+            ParseOpenMPDeclareMapperDirective(/*AS=*/AS_none)) {
+      // Skip the last annot_pragma_openmp_end.
+      ConsumeAnnotationToken();
+      Directive = Actions.ActOnDeclStmt(Res, Loc, Tok.getLocation());
+    } else {
+      SkipUntil(tok::annot_pragma_openmp_end);
+    }
+    break;
+  }
   case OMPD_flush:
     if (PP.LookAhead(0).is(tok::l_paren)) {
       FlushHasClause = true;