Introduce a new kind of TemplateName that captures a substituted

template template parameter pack that cannot be fully expanded because
its enclosing pack expansion could not be expanded. This form of
TemplateName plays the same role as SubstTemplateTypeParmPackType and
SubstNonTypeTemplateParmPackExpr do for template type parameter packs
and non-type template parameter packs, respectively.

We should now handle these multi-level pack expansion substitutions
anywhere. The largest remaining gap in our variadic-templates support
is that we cannot cope with non-type template parameter packs whose
type is a pack expansion.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123521 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 30 insertions, 0 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index e1e6fd08aa..a18247d7ce 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -2737,6 +2737,15 @@ TemplateName ASTContext::getCanonicalTemplateName(TemplateName Name) const {
     return TemplateName(cast<TemplateDecl>(Template->getCanonicalDecl()));
   }
 
+  if (SubstTemplateTemplateParmPackStorage *SubstPack
+                                  = Name.getAsSubstTemplateTemplateParmPack()) {
+    TemplateTemplateParmDecl *CanonParam
+      = getCanonicalTemplateTemplateParmDecl(SubstPack->getParameterPack());
+    TemplateArgument CanonArgPack
+      = getCanonicalTemplateArgument(SubstPack->getArgumentPack());
+    return getSubstTemplateTemplateParmPack(CanonParam, CanonArgPack);
+  }
+      
   assert(!Name.getAsOverloadedTemplate());
 
   DependentTemplateName *DTN = Name.getAsDependentTemplateName();
@@ -4344,6 +4353,27 @@ ASTContext::getDependentTemplateName(NestedNameSpecifier *NNS,
   return TemplateName(QTN);
 }
 
+TemplateName 
+ASTContext::getSubstTemplateTemplateParmPack(TemplateTemplateParmDecl *Param,
+                                       const TemplateArgument &ArgPack) const {
+  ASTContext &Self = const_cast<ASTContext &>(*this);
+  llvm::FoldingSetNodeID ID;
+  SubstTemplateTemplateParmPackStorage::Profile(ID, Self, Param, ArgPack);
+  
+  void *InsertPos = 0;
+  SubstTemplateTemplateParmPackStorage *Subst
+    = SubstTemplateTemplateParmPacks.FindNodeOrInsertPos(ID, InsertPos);
+  
+  if (!Subst) {
+    Subst = new (*this) SubstTemplateTemplateParmPackStorage(Self, Param, 
+                                                           ArgPack.pack_size(),
+                                                         ArgPack.pack_begin());
+    SubstTemplateTemplateParmPacks.InsertNode(Subst, InsertPos);
+  }
+
+  return TemplateName(Subst);
+}
+
 /// getFromTargetType - Given one of the integer types provided by
 /// TargetInfo, produce the corresponding type. The unsigned @p Type
 /// is actually a value of type @c TargetInfo::IntType.