Provide the correct mangling and linkage for certain unnamed nested classes.

This corrects the mangling and linkage of classes (& their member functions) in
cases like this:

  struct foo {
    struct {
      void func() { ... }
    } x;
  };

we were accidentally giving this nested unnamed struct 'no' linkage where it
should've had the linkage of the outer class. The mangling was incorrecty too,
mangling as TU-wide unnamed type mangling of $_X rather than class-scoped
mangling of UtX_.

This also fixes -Wunused-member-function which would incorrectly diagnose
'func' as unused due to it having no linkage & thus appearing to be TU-local
when in fact it might be correctly used in another TU.

Similar mangling should be applied to function local classes in similar cases
but I've deferred that for a subsequent patch.

Review/discussion by Richard Smith, John McCall, & especially Eli Friedman.

llvm-svn: 167906

1 files changed, 21 insertions, 1 deletions

diff --git a/clang/test/CodeGenCXX/mangle.cpp b/clang/test/CodeGenCXX/mangle.cpp
index ba1b3bf5acd..5dad030d5ea 100644
--- a/clang/test/CodeGenCXX/mangle.cpp
+++ b/clang/test/CodeGenCXX/mangle.cpp
@@ -218,7 +218,7 @@ struct S7 {
 // PR5139
 // CHECK: @_ZN2S7C1Ev
 // CHECK: @_ZN2S7C2Ev
-// CHECK: @"_ZN2S73$_0C1Ev"
+// CHECK: @_ZN2S7Ut_C1Ev
 S7::S7() {}
 
 // PR5063
@@ -852,3 +852,23 @@ namespace test36 {
   // CHECK: define weak_odr {{.*}} @_ZN6test362f1IJifEEENS_1AIXsZfp_EEEDpT_
   template A<2> f1(int, float);
 }
+
+namespace test37 {
+  struct foo {
+    struct {
+    } a;
+    typedef struct { } b;
+    typedef struct { } *c;
+    struct {
+    } d;
+  };
+  template<typename T> void func(T) { }
+  void test() {
+    // CHECK: define linkonce_odr void @_ZN6test374funcINS_3fooUt_EEEvT_
+    func(foo().a);
+    // CHECK: define linkonce_odr void @_ZN6test374funcINS_3fooUt0_EEEvT_
+    func(*foo::c());
+    // CHECK: define linkonce_odr void @_ZN6test374funcINS_3fooUt1_EEEvT_
+    func(foo().d);
+  }
+}