Discussing with dgregor we decided that we should not force the emission of

implicit methods on explicit template instantiation definitions. As a
consequence, we should emit them at every use, even if we see a explicit
template instantiation declaration.

This is already the current behaviour, but it is good to test for that :-)

llvm-svn: 99443

clang/test/CodeGenCXX/template-instantiation.cpp

@@ -3,6 +3,10 @@
 // CHECK-NOT: @_ZTVN5test118stdio_sync_filebufIwEE = constant
 // CHECK: @_ZTVN5test018stdio_sync_filebufIwEE = constant
 
+// CHECK: define linkonce_odr void @_ZN5test21CIiEC1Ev(
+// CHECK: define linkonce_odr void @_ZN5test21CIiE6foobarIdEEvT_(
+// CHECK: define available_externally void @_ZN5test21CIiE6zedbarEd(
+
 namespace test0 {
   struct  basic_streambuf   {
     virtual       ~basic_streambuf();
@@ -31,3 +35,28 @@ namespace test1 {
   // Just a declaration should not force the vtable to be emitted.
   template<> void stdio_sync_filebuf<wchar_t>::xsgetn();
 }
+
+namespace test2 {
+  template<typename T1>
+  class C {
+    virtual ~C();
+    void zedbar(double) {
+    }
+    template<typename T2>
+    void foobar(T2 foo) {
+    }
+  };
+  extern template class C<int>;
+  void g() {
+    // The extern template declaration should not prevent us from producing
+    // the implicit constructor (test at the top).
+    C<int> a;
+
+    // or foobar(test at the top).
+    a.foobar(0.0);
+
+    // But it should prevent zebbar
+    // (test at the top).
+    a.zedbar(0.0);
+  }
+}