Fix a small difference in sema and codegen views of what needs to be output.

In the included testcase, soma thinks that we already have a definition after we
see the out of line decl. Codegen puts it in a deferred list, to be output if
a use is seen. This would break when we saw an explicit template instantiation
definition, since codegen would not be notified.

This patch adds a method to the consumer interface so that soma can notify
codegen that this decl is now required.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152024 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index d491dfc..4633db7 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2596,21 +2596,25 @@
     return;
   }
 
+  TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
+
   // Never instantiate an explicit specialization.
-  if (Var->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
+  if (TSK == TSK_ExplicitSpecialization)
     return;
 
   // C++0x [temp.explicit]p9:
   //   Except for inline functions, other explicit instantiation declarations
   //   have the effect of suppressing the implicit instantiation of the entity
   //   to which they refer.
-  if (Var->getTemplateSpecializationKind()
-        == TSK_ExplicitInstantiationDeclaration)
+  if (TSK == TSK_ExplicitInstantiationDeclaration)
     return;
 
   // If we already have a definition, we're done.
-  if (Var->getDefinition())
+  if (Var->getDefinition()) {
+    if (TSK == TSK_ExplicitInstantiationDefinition)
+      Consumer.MarkVarRequired(Var);
     return;
+  }
 
   InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);
   if (Inst)