[c++20] For P0732R2 / P1907R1: Basic frontend support for class types as

non-type template parameters.

Create a unique TemplateParamObjectDecl instance for each such value,
representing the globally unique template parameter object to which the
template parameter refers.

No IR generation support yet; that will follow in a separate patch.

1 files changed, 19 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 485cb85..419b25d 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -1123,6 +1123,7 @@ static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
   case InitializedEntity::EK_ArrayElement:
   case InitializedEntity::EK_Parameter:
   case InitializedEntity::EK_Parameter_CF_Audited:
+  case InitializedEntity::EK_TemplateParameter:
   case InitializedEntity::EK_Result:
     // Extra braces here are suspicious.
     DiagID = diag::warn_braces_around_init;
@@ -3283,6 +3284,7 @@ DeclarationName InitializedEntity::getName() const {
   case EK_Variable:
   case EK_Member:
   case EK_Binding:
+  case EK_TemplateParameter:
     return Variable.VariableOrMember->getDeclName();
 
   case EK_LambdaCapture:
@@ -3313,6 +3315,7 @@ ValueDecl *InitializedEntity::getDecl() const {
   case EK_Variable:
   case EK_Member:
   case EK_Binding:
+  case EK_TemplateParameter:
     return Variable.VariableOrMember;
 
   case EK_Parameter:
@@ -3350,6 +3353,7 @@ bool InitializedEntity::allowsNRVO() const {
   case EK_Variable:
   case EK_Parameter:
   case EK_Parameter_CF_Audited:
+  case EK_TemplateParameter:
   case EK_Member:
   case EK_Binding:
   case EK_New:
@@ -3381,6 +3385,7 @@ unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
   case EK_Parameter: OS << "Parameter"; break;
   case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
     break;
+  case EK_TemplateParameter: OS << "TemplateParameter"; break;
   case EK_Result: OS << "Result"; break;
   case EK_StmtExprResult: OS << "StmtExprResult"; break;
   case EK_Exception: OS << "Exception"; break;
@@ -6001,6 +6006,11 @@ getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
     // FIXME: Can we tell apart casting vs. converting?
     return Sema::AA_Casting;
 
+  case InitializedEntity::EK_TemplateParameter:
+    // This is really initialization, but refer to it as conversion for
+    // consistency with CheckConvertedConstantExpression.
+    return Sema::AA_Converting;
+
   case InitializedEntity::EK_Member:
   case InitializedEntity::EK_Binding:
   case InitializedEntity::EK_ArrayElement:
@@ -6035,6 +6045,7 @@ static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
   case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
   case InitializedEntity::EK_LambdaCapture:
   case InitializedEntity::EK_CompoundLiteralInit:
+  case InitializedEntity::EK_TemplateParameter:
     return false;
 
   case InitializedEntity::EK_Parameter:
@@ -6069,6 +6080,7 @@ static bool shouldDestroyEntity(const InitializedEntity &Entity) {
     case InitializedEntity::EK_Variable:
     case InitializedEntity::EK_Parameter:
     case InitializedEntity::EK_Parameter_CF_Audited:
+    case InitializedEntity::EK_TemplateParameter:
     case InitializedEntity::EK_Temporary:
     case InitializedEntity::EK_ArrayElement:
     case InitializedEntity::EK_Exception:
@@ -6102,6 +6114,7 @@ static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
   case InitializedEntity::EK_Member:
   case InitializedEntity::EK_Parameter:
   case InitializedEntity::EK_Parameter_CF_Audited:
+  case InitializedEntity::EK_TemplateParameter:
   case InitializedEntity::EK_Temporary:
   case InitializedEntity::EK_New:
   case InitializedEntity::EK_Base:
@@ -6345,7 +6358,7 @@ static void CheckCXX98CompatAccessibleCopy(Sema &S,
 
 void InitializationSequence::PrintInitLocationNote(Sema &S,
                                               const InitializedEntity &Entity) {
-  if (Entity.isParameterKind() && Entity.getDecl()) {
+  if (Entity.isParamOrTemplateParamKind() && Entity.getDecl()) {
     if (Entity.getDecl()->getLocation().isInvalid())
       return;
 
@@ -6611,6 +6624,10 @@ static LifetimeResult getEntityLifetime(
     //      the call.
     return {nullptr, LK_FullExpression};
 
+  case InitializedEntity::EK_TemplateParameter:
+    // FIXME: This will always be ill-formed; should we eagerly diagnose it here?
+    return {nullptr, LK_FullExpression};
+
   case InitializedEntity::EK_Result:
     //   -- The lifetime of a temporary bound to the returned value in a
     //      function return statement is not extended; the temporary is
@@ -7882,7 +7899,7 @@ ExprResult InitializationSequence::Perform(Sema &S,
 
   if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
       Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
-      !Entity.isParameterKind()) {
+      !Entity.isParamOrTemplateParamKind()) {
     // Produce a C++98 compatibility warning if we are initializing a reference
     // from an initializer list. For parameters, we produce a better warning
     // elsewhere.