[CIR][NFC] Upstream bulk handling for Decl kinds (llvm#138319)

This adds explicit case statements for Decl types that weren't
explicitly present in the emitDecl function. Those that need no handling
are just accepted. Those that will need handling still go to errorNYI,
but the default statement is removed.

Author: andykaylor

clang/lib/CIR/CodeGen/CIRGenDecl.cpp

@@ -268,11 +268,87 @@ void CIRGenFunction::emitExprAsInit(const Expr *init, const ValueDecl *d,
 
 void CIRGenFunction::emitDecl(const Decl &d) {
   switch (d.getKind()) {
-  case Decl::LinkageSpec:
+  case Decl::BuiltinTemplate:
+  case Decl::TranslationUnit:
+  case Decl::ExternCContext:
   case Decl::Namespace:
+  case Decl::UnresolvedUsingTypename:
+  case Decl::ClassTemplateSpecialization:
+  case Decl::ClassTemplatePartialSpecialization:
+  case Decl::VarTemplateSpecialization:
+  case Decl::VarTemplatePartialSpecialization:
+  case Decl::TemplateTypeParm:
+  case Decl::UnresolvedUsingValue:
+  case Decl::NonTypeTemplateParm:
+  case Decl::CXXDeductionGuide:
+  case Decl::CXXMethod:
+  case Decl::CXXConstructor:
+  case Decl::CXXDestructor:
+  case Decl::CXXConversion:
+  case Decl::Field:
+  case Decl::MSProperty:
+  case Decl::IndirectField:
+  case Decl::ObjCIvar:
+  case Decl::ObjCAtDefsField:
+  case Decl::ParmVar:
+  case Decl::ImplicitParam:
+  case Decl::ClassTemplate:
+  case Decl::VarTemplate:
+  case Decl::FunctionTemplate:
+  case Decl::TypeAliasTemplate:
+  case Decl::TemplateTemplateParm:
+  case Decl::ObjCMethod:
+  case Decl::ObjCCategory:
+  case Decl::ObjCProtocol:
+  case Decl::ObjCInterface:
+  case Decl::ObjCCategoryImpl:
+  case Decl::ObjCImplementation:
+  case Decl::ObjCProperty:
+  case Decl::ObjCCompatibleAlias:
+  case Decl::PragmaComment:
+  case Decl::PragmaDetectMismatch:
+  case Decl::AccessSpec:
+  case Decl::LinkageSpec:
+  case Decl::Export:
+  case Decl::ObjCPropertyImpl:
+  case Decl::FileScopeAsm:
+  case Decl::Friend:
+  case Decl::FriendTemplate:
+  case Decl::Block:
+  case Decl::OutlinedFunction:
+  case Decl::Captured:
+  case Decl::UsingShadow:
+  case Decl::ConstructorUsingShadow:
+  case Decl::ObjCTypeParam:
+  case Decl::Binding:
+  case Decl::UnresolvedUsingIfExists:
     llvm_unreachable("Declaration should not be in declstmts!");
 
+  case Decl::Function:     // void X();
+  case Decl::EnumConstant: // enum ? { X = ? }
+  case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
+  case Decl::Label:        // __label__ x;
+  case Decl::Import:
+  case Decl::MSGuid: // __declspec(uuid("..."))
+  case Decl::TemplateParamObject:
+  case Decl::OMPThreadPrivate:
+  case Decl::OMPAllocate:
+  case Decl::OMPCapturedExpr:
+  case Decl::OMPRequires:
+  case Decl::Empty:
+  case Decl::Concept:
+  case Decl::LifetimeExtendedTemporary:
+  case Decl::RequiresExprBody:
+  case Decl::UnnamedGlobalConstant:
+    // None of these decls require codegen support.
+    return;
+
+  case Decl::Enum:   // enum X;
   case Decl::Record: // struct/union/class X;
+  case Decl::CXXRecord: // struct/union/class X; [C++]
+  case Decl::NamespaceAlias:
+  case Decl::Using:          // using X; [C++]
+  case Decl::UsingEnum:      // using enum X; [C++]
   case Decl::UsingDirective: // using namespace X; [C++]
     assert(!cir::MissingFeatures::generateDebugInfo());
     return;
@@ -297,7 +373,13 @@ void CIRGenFunction::emitDecl(const Decl &d) {
       cgm.errorNYI(d.getSourceRange(), "emitDecl: variably modified type");
     return;
   }
-  default:
+  case Decl::ImplicitConceptSpecialization:
+  case Decl::HLSLBuffer:
+  case Decl::TopLevelStmt:
+  case Decl::UsingPack:
+  case Decl::Decomposition: // This could be moved to join Decl::Var
+  case Decl::OMPDeclareReduction:
+  case Decl::OMPDeclareMapper:
     cgm.errorNYI(d.getSourceRange(),
                  std::string("emitDecl: unhandled decl type: ") +
                      d.getDeclKindName());