[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

llvm-svn: 352906

1 files changed, 83 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 883a73f2266..e3f57e00381 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2924,6 +2924,87 @@ Decl *TemplateDeclInstantiator::VisitOMPDeclareReductionDecl(
   return NewDRD;
 }
 
+Decl *
+TemplateDeclInstantiator::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
+  // Instantiate type and check if it is allowed.
+  const bool RequiresInstantiation =
+      D->getType()->isDependentType() ||
+      D->getType()->isInstantiationDependentType() ||
+      D->getType()->containsUnexpandedParameterPack();
+  QualType SubstMapperTy;
+  DeclarationName VN = D->getVarName();
+  if (RequiresInstantiation) {
+    SubstMapperTy = SemaRef.ActOnOpenMPDeclareMapperType(
+        D->getLocation(),
+        ParsedType::make(SemaRef.SubstType(D->getType(), TemplateArgs,
+                                           D->getLocation(), VN)));
+  } else {
+    SubstMapperTy = D->getType();
+  }
+  if (SubstMapperTy.isNull())
+    return nullptr;
+  // Create an instantiated copy of mapper.
+  auto *PrevDeclInScope = D->getPrevDeclInScope();
+  if (PrevDeclInScope && !PrevDeclInScope->isInvalidDecl()) {
+    PrevDeclInScope = cast<OMPDeclareMapperDecl>(
+        SemaRef.CurrentInstantiationScope->findInstantiationOf(PrevDeclInScope)
+            ->get<Decl *>());
+  }
+  OMPDeclareMapperDecl *NewDMD = SemaRef.ActOnOpenMPDeclareMapperDirectiveStart(
+      /*S=*/nullptr, Owner, D->getDeclName(), SubstMapperTy, D->getLocation(),
+      VN, D->getAccess(), PrevDeclInScope);
+  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewDMD);
+  SmallVector<OMPClause *, 6> Clauses;
+  bool IsCorrect = true;
+  if (!RequiresInstantiation) {
+    // Copy the mapper variable.
+    NewDMD->setMapperVarRef(D->getMapperVarRef());
+    // Copy map clauses from the original mapper.
+    for (OMPClause *C : D->clauselists())
+      Clauses.push_back(C);
+  } else {
+    // Instantiate the mapper variable.
+    DeclarationNameInfo DirName;
+    SemaRef.StartOpenMPDSABlock(OMPD_declare_mapper, DirName, /*S=*/nullptr,
+                                (*D->clauselist_begin())->getBeginLoc());
+    SemaRef.ActOnOpenMPDeclareMapperDirectiveVarDecl(
+        NewDMD, /*S=*/nullptr, SubstMapperTy, D->getLocation(), VN);
+    SemaRef.CurrentInstantiationScope->InstantiatedLocal(
+        cast<DeclRefExpr>(D->getMapperVarRef())->getDecl(),
+        cast<DeclRefExpr>(NewDMD->getMapperVarRef())->getDecl());
+    auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);
+    Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, Qualifiers(),
+                                     ThisContext);
+    // Instantiate map clauses.
+    for (OMPClause *C : D->clauselists()) {
+      auto *OldC = cast<OMPMapClause>(C);
+      SmallVector<Expr *, 4> NewVars;
+      for (Expr *OE : OldC->varlists()) {
+        Expr *NE = SemaRef.SubstExpr(OE, TemplateArgs).get();
+        if (!NE) {
+          IsCorrect = false;
+          break;
+        }
+        NewVars.push_back(NE);
+      }
+      if (!IsCorrect)
+        break;
+      OMPClause *NewC = SemaRef.ActOnOpenMPMapClause(
+          OldC->getMapTypeModifiers(), OldC->getMapTypeModifiersLoc(),
+          OldC->getMapType(), OldC->isImplicitMapType(), OldC->getMapLoc(),
+          OldC->getColonLoc(), NewVars, OldC->getBeginLoc(),
+          OldC->getLParenLoc(), OldC->getEndLoc());
+      Clauses.push_back(NewC);
+    }
+    SemaRef.EndOpenMPDSABlock(nullptr);
+  }
+  (void)SemaRef.ActOnOpenMPDeclareMapperDirectiveEnd(NewDMD, /*S=*/nullptr,
+                                                     Clauses);
+  if (!IsCorrect)
+    return nullptr;
+  return NewDMD;
+}
+
 Decl *TemplateDeclInstantiator::VisitOMPCapturedExprDecl(
     OMPCapturedExprDecl * /*D*/) {
   llvm_unreachable("Should not be met in templates");
@@ -5005,7 +5086,8 @@ NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
   if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||
       isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||
       ((ParentDC->isFunctionOrMethod() ||
-        isa<OMPDeclareReductionDecl>(ParentDC)) &&
+        isa<OMPDeclareReductionDecl>(ParentDC) ||
+        isa<OMPDeclareMapperDecl>(ParentDC)) &&
        ParentDC->isDependentContext()) ||
       (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda())) {
     // D is a local of some kind. Look into the map of local