Patch implements ranking conversions between member pointers [over.ics.rank]

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@84660 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 80 insertions, 7 deletions

diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 0da13fc667..8c307f7d61 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -1935,13 +1935,42 @@ Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1,
     }
   }
 
-
-  // FIXME: conversion of A::* to B::* is better than conversion of
-  // A::* to C::*,
-
-  // FIXME: conversion of B::* to C::* is better than conversion of
-  // A::* to C::*, and
-
+  // conversion of A::* to B::* is better than conversion of A::* to C::*,
+
+  if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
+      FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
+      ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
+    const MemberPointerType * FromMemPointer1 = 
+                                        FromType1->getAs<MemberPointerType>();
+    const MemberPointerType * ToMemPointer1 = 
+                                          ToType1->getAs<MemberPointerType>();
+    const MemberPointerType * FromMemPointer2 = 
+                                          FromType2->getAs<MemberPointerType>();
+    const MemberPointerType * ToMemPointer2 = 
+                                          ToType2->getAs<MemberPointerType>();
+    const Type *FromPointeeType1 = FromMemPointer1->getClass();
+    const Type *ToPointeeType1 = ToMemPointer1->getClass();
+    const Type *FromPointeeType2 = FromMemPointer2->getClass();
+    const Type *ToPointeeType2 = ToMemPointer2->getClass();
+    QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
+    QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
+    QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
+    QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
+    if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
+      if (IsDerivedFrom(ToPointee1, ToPointee2))
+        return ImplicitConversionSequence::Worse;
+      else if (IsDerivedFrom(ToPointee2, ToPointee1))
+        return ImplicitConversionSequence::Better;
+    }
+    // conversion of B::* to C::* is better than conversion of A::* to C::*
+    if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
+      if (IsDerivedFrom(FromPointee1, FromPointee2))
+        return ImplicitConversionSequence::Better;
+      else if (IsDerivedFrom(FromPointee2, FromPointee1))
+        return ImplicitConversionSequence::Worse;
+    }
+  }
+  
   if (SCS1.CopyConstructor && SCS2.CopyConstructor &&
       SCS1.Second == ICK_Derived_To_Base) {
     //   -- conversion of C to B is better than conversion of C to A,
diff --git a/test/SemaCXX/ptrtomember-overload-resolution.cpp b/test/SemaCXX/ptrtomember-overload-resolution.cpp
new file mode 100644
index 0000000000..b3b65ce840
--- /dev/null
+++ b/test/SemaCXX/ptrtomember-overload-resolution.cpp
@@ -0,0 +1,44 @@
+// RUN: clang-cc -fsyntax-only -verify %s -std=c++0x
+
+// 13.3.3.2 Ranking implicit conversion sequences
+// conversion of A::* to B::* is better than conversion of A::* to C::*,
+struct A {
+int Ai;
+}; 
+
+struct B : public A {}; 
+struct C : public B {}; 
+
+const char * f(int C::*){ return ""; } 
+int f(int B::*) { return 1; } 
+
+struct D : public C {}; 
+
+const char * g(int B::*){ return ""; } 
+int g(int D::*) { return 1; } 
+
+void test() 
+{
+  int i = f(&A::Ai);
+
+  const char * str = g(&A::Ai);
+}
+
+// conversion of B::* to C::* is better than conversion of A::* to C::*
+typedef void (A::*pmfa)();
+typedef void (B::*pmfb)();
+typedef void (C::*pmfc)();
+
+struct X {
+	operator pmfa();
+	operator pmfb();
+};
+
+
+void g(pmfc);
+
+void test2(X x) 
+{
+    g(x);
+}
+