[PATCH] D13330: Implement __attribute__((unique_instantiation))

[Keno Fischer via cfe-commits]

loladiro added inline comments.

================
Comment at: lib/AST/ASTContext.cpp:8257-8266
@@ -8256,1 +8256,12 @@
 
+bool ASTContext::containedInUniqueInstantiation(const Decl *D) {
+  const RecordDecl *RD;
+  while ((RD = dyn_cast<RecordDecl>(D->getDeclContext()))) {
+    auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
+    if (CTSD && CTSD->hasAttr<UniqueInstantiationAttr>())
+      return true;
+    D = RD;
+  }
+  return false;
+}
+
----------------
majnemer wrote:
> Function templates can contain class templates which contain functions.  I think this code will return false if the outermost function template is the only one annotated with UniqueInstantiationAttr.
So you're concerned about this case:
```
template < typename T > auto foo( T x ) {
  class inner {
      T y;
  public:
      virtual ~inner() {}
      inner(T y) : y(y) {}
      T getY() { return y; }
  };
  return inner{x}.getY();
}

extern template __attribute__((unique_instantiation)) auto foo<int>(int);
template __attribute__((unique_instantiation)) auto foo<int>(int);
```
Right now the inner class's vtable and method is linkonce_odr. If you think it should be strong I'll look into it.


http://reviews.llvm.org/D13330