[clang] Make sure attributes on member classes are applied properly

Summary:
Attributes on member classes of class templates and member class templates
of class templates are not currently instantiated. This was discovered by
Richard Smith here:

  http://lists.llvm.org/pipermail/cfe-dev/2018-September/059291.html

This commit makes sure that attributes are instantiated properly. This
commit does not fix the broken behavior for member partial and explicit
specializations of class templates.

PR38913

Reviewers: rsmith

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51997

llvm-svn: 342238

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -1258,6 +1258,9 @@ Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
   if (QualifierLoc)
     RecordInst->setQualifierInfo(QualifierLoc);
 
+  SemaRef.InstantiateAttrsForDecl(TemplateArgs, Pattern, RecordInst, LateAttrs,
+                                                              StartingScope);
+
   ClassTemplateDecl *Inst
     = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),
                                 D->getIdentifier(), InstParams, RecordInst);
@@ -1491,6 +1494,9 @@ Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
   if (SubstQualifier(D, Record))
     return nullptr;
 
+  SemaRef.InstantiateAttrsForDecl(TemplateArgs, D, Record, LateAttrs,
+                                                              StartingScope);
+
   Record->setImplicit(D->isImplicit());
   // FIXME: Check against AS_none is an ugly hack to work around the issue that
   // the tag decls introduced by friend class declarations don't have an access

clang/test/SemaCXX/PR38913.cpp

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s
+
+// PR38913
+// Check that we instantiate attributes on declarations for...
+
+// ...a member class of a class template specialization
+template<class T> struct A { struct __attribute__((abi_tag("ATAG"))) X { }; };
+A<int>::X* a() { return 0; } // CHECK-DAG: @_Z1aB4ATAGv
+
+// ...a member class template
+template<class T> struct B { template<class U> struct __attribute__((abi_tag("BTAG"))) X { }; };
+B<int>::X<int>* b() { return 0; } // CHECK-DAG: @_Z1bB4BTAGv