-ms-extensions: Implement __super scope specifier (PR13236).

We build a NestedNameSpecifier that records the CXXRecordDecl in which
__super appeared. Name lookup is performed in all base classes of the
recorded CXXRecordDecl. Use of __super is allowed only inside class and
member function scope.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@218484 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 1 deletions

diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index d3f0fad315..739cba7233 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -148,6 +148,9 @@ DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
 
   case NestedNameSpecifier::Global:
     return Context.getTranslationUnitDecl();
+
+  case NestedNameSpecifier::Super:
+    return NNS->getAsRecordDecl();
   }
 
   llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
@@ -240,12 +243,43 @@ bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
   return true;
 }
 
-bool Sema::ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
+bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
                                         CXXScopeSpec &SS) {
   SS.MakeGlobal(Context, CCLoc);
   return false;
 }
 
+bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
+                                    SourceLocation ColonColonLoc,
+                                    CXXScopeSpec &SS) {
+  CXXRecordDecl *RD = nullptr;
+  for (Scope *S = getCurScope(); S; S = S->getParent()) {
+    if (S->isFunctionScope()) {
+      if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
+        RD = MD->getParent();
+      break;
+    }
+    if (S->isClassScope()) {
+      RD = cast<CXXRecordDecl>(S->getEntity());
+      break;
+    }
+  }
+
+  if (!RD) {
+    Diag(SuperLoc, diag::err_invalid_super_scope);
+    return true;
+  } else if (RD->isLambda()) {
+    Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
+    return true;
+  } else if (RD->getNumBases() == 0) {
+    Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
+    return true;
+  }
+
+  SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
+  return false;
+}
+
 /// \brief Determines whether the given declaration is an valid acceptable
 /// result for name lookup of a nested-name-specifier.
 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD) {
@@ -953,6 +987,7 @@ bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
   case NestedNameSpecifier::Identifier:
   case NestedNameSpecifier::TypeSpec:
   case NestedNameSpecifier::TypeSpecWithTemplate:
+  case NestedNameSpecifier::Super:
     // These are never namespace scopes.
     return true;
   }