Always mark friend function declarations in class templates as

implicitly instantiable, even if we don't see a body on the friend
function declaration. The body may simply have not yet been attached.
This fixes PR10666.

There may be an alternate, preferred implementation strategy, see my
FIXME. Review would definitely be appreciated Doug. =D

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137934 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 812482e436172a62cf19e934bf84b665bab8655a..a1ae00cb1cd68b0c4a762abfaaf1982aa4569130 100644 (file)
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1153,9 +1153,13 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
                                                              Innermost.first,
                                                              Innermost.second),
                                                 InsertPos);
-  } else if (isFriend && D->isThisDeclarationADefinition()) {
-    // TODO: should we remember this connection regardless of whether
-    // the friend declaration provided a body?
+  } else if (isFriend) {
+    // Note, we need this connection even if the friend doesn't have a body.
+    // Its body may exist but not have been attached yet due to deferred
+    // parsing.
+    // FIXME: It might be cleaner to set this when attaching the body to the
+    // friend function declaration, however that would require finding all the
+    // instantiations and modifying them.
     Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);
   }
     

diff --git a/test/CodeGenCXX/template-instantiation.cpp b/test/CodeGenCXX/template-instantiation.cpp
index cc30af0aba4bd55d69b4f071be8f7b340fb64049..09b3a4fcc544a29411eb089abb6b66f0c81751c1 100644 (file)
--- a/test/CodeGenCXX/template-instantiation.cpp
+++ b/test/CodeGenCXX/template-instantiation.cpp
@@ -17,6 +17,19 @@
 // CHECK: define linkonce_odr void @_ZN5test21CIiE6foobarIdEEvT_(
 // CHECK: define available_externally void @_ZN5test21CIiE6zedbarEd(
 
+// CHECK: define linkonce_odr void @_ZN7PR106662g1ENS_1SILi1EEE()
+// CHECK: define linkonce_odr void @_ZN7PR106662g1ENS_1SILi2EEE()
+// CHECK: define linkonce_odr void @_ZN7PR106662g1ENS_1SILi3EEE()
+// CHECK: define linkonce_odr void @_ZN7PR106662g2ENS_1SILi1EEE()
+// CHECK: define linkonce_odr void @_ZN7PR106662g2ENS_1SILi2EEE()
+// CHECK: define linkonce_odr void @_ZN7PR106662g2ENS_1SILi3EEE()
+// CHECK: declare void @_ZN7PR106662h1ENS_1SILi1EEE()
+// CHECK: declare void @_ZN7PR106662h1ENS_1SILi2EEE()
+// CHECK: declare void @_ZN7PR106662h1ENS_1SILi3EEE()
+// CHECK: declare void @_ZN7PR106662h2ENS_1SILi1EEE()
+// CHECK: declare void @_ZN7PR106662h2ENS_1SILi2EEE()
+// CHECK: declare void @_ZN7PR106662h2ENS_1SILi3EEE()
+
 namespace test0 {
   struct  basic_streambuf   {
     virtual       ~basic_streambuf();
@@ -152,3 +165,26 @@ namespace PR10001 {
 
   int x = S<int>::f();
 }
+
+// Ensure that definitions are emitted for all friend functions defined within
+// class templates. Order of declaration is extremely important here. Different
+// instantiations of the class happen at different points during the deferred
+// method body parsing and afterward. Those different points of instantiation
+// change the exact form the class template appears to have.
+namespace PR10666 {
+  template <int N> struct S {
+    void f1() { S<1> s; }
+    friend void g1(S s) {}
+    friend void h1(S s);
+    void f2() { S<2> s; }
+    friend void g2(S s) {}
+    friend void h2(S s);
+    void f3() { S<3> s; }
+  };
+  void test(S<1> s1, S<2> s2, S<3> s3) {
+    g1(s1); g1(s2); g1(s3);
+    g2(s1); g2(s2); g2(s3);
+    h1(s1); h1(s2); h1(s3);
+    h2(s1); h2(s2); h2(s3);
+  }
+}