Implement basic parsing and semantic analysis for explicit
specialization of class templates, e.g.,

  template<typename T> class X;

  template<> class X<int> { /* blah */ };

Each specialization is a different *Decl node (naturally), and can
have different members. We keep track of forward declarations and
definitions as for other class/struct/union types.

This is only the basic framework: we still have to deal with checking
the template headers properly, improving recovery when there are
failures, handling nested name specifiers, etc.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64848 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index 826b4b0..db29a8e 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -319,17 +319,6 @@
     // The original namespace is our primary context.
     return static_cast<NamespaceDecl*>(this)->getOriginalNamespace();
 
-  case Decl::Enum:
-  case Decl::Record:
-  case Decl::CXXRecord:
-    // If this is a tag type that has a definition or is currently
-    // being defined, that definition is our primary context.
-    if (TagType *TagT = cast_or_null<TagType>(cast<TagDecl>(this)->TypeForDecl))
-      if (TagT->isBeingDefined() || 
-          (TagT->getDecl() && TagT->getDecl()->isDefinition()))
-        return TagT->getDecl();
-    return this;
-
   case Decl::ObjCMethod:
     return this;
 
@@ -344,6 +333,17 @@
     return this;
 
   default:
+    if (DeclKind >= Decl::TagFirst && DeclKind <= Decl::TagLast) {
+      // If this is a tag type that has a definition or is currently
+      // being defined, that definition is our primary context.
+      if (TagType *TagT 
+            = cast_or_null<TagType>(cast<TagDecl>(this)->TypeForDecl))
+        if (TagT->isBeingDefined() || 
+            (TagT->getDecl() && TagT->getDecl()->isDefinition()))
+          return TagT->getDecl();
+      return this;
+    }
+
     assert(DeclKind >= Decl::FunctionFirst && DeclKind <= Decl::FunctionLast &&
           "Unknown DeclContext kind");
     return this;
@@ -352,28 +352,11 @@
 
 DeclContext *DeclContext::getNextContext() {
   switch (DeclKind) {
-  case Decl::TranslationUnit:
-  case Decl::Enum:
-  case Decl::Record:
-  case Decl::CXXRecord:
-  case Decl::ObjCMethod:
-  case Decl::ObjCInterface:
-  case Decl::ObjCCategory:
-  case Decl::ObjCProtocol:
-  case Decl::ObjCImplementation:
-  case Decl::ObjCCategoryImpl:
-  case Decl::LinkageSpec:
-  case Decl::Block:
-    // There is only one DeclContext for these entities.
-    return 0;
-
   case Decl::Namespace:
     // Return the next namespace
     return static_cast<NamespaceDecl*>(this)->getNextNamespace();
 
   default:
-    assert(DeclKind >= Decl::FunctionFirst && DeclKind <= Decl::FunctionLast &&
-          "Unknown DeclContext kind");
     return 0;
   }
 }
@@ -463,6 +446,12 @@
 }
 
 void DeclContext::makeDeclVisibleInContext(NamedDecl *D) {
+  // FIXME: This feels like a hack. Should DeclarationName support
+  // template-ids, or is there a better way to keep specializations
+  // from being visible?
+  if (isa<ClassTemplateSpecializationDecl>(D))
+    return;
+
   DeclContext *PrimaryContext = getPrimaryContext();
   if (PrimaryContext != this) {
     PrimaryContext->makeDeclVisibleInContext(D);
@@ -486,6 +475,12 @@
   if (!D->getDeclName())
     return;
 
+  // FIXME: This feels like a hack. Should DeclarationName support
+  // template-ids, or is there a better way to keep specializations
+  // from being visible?
+  if (isa<ClassTemplateSpecializationDecl>(D))
+    return;
+
   bool MayBeRedeclaration = true;
 
   if (!isLookupMap()) {