r198343 - Objective-C ARC++: Prefer references to __strong/__weak over __unsafe_unretained.

[Douglas Gregor]

Author: dgregor
Date: Thu Jan  2 13:42:02 2014
New Revision: 198343

URL: http://llvm.org/viewvc/llvm-project?rev=198343&view=rev
Log:
Objective-C ARC++: Prefer references to __strong/__weak over __unsafe_unretained.

Fixes <rdar://problem/15713945>.

Modified:
    cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
    cfe/trunk/test/SemaObjCXX/arc-templates.mm

Modified: cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp?rev=198343&r1=198342&r2=198343&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp Thu Jan  2 13:42:02 2014
@@ -981,6 +981,17 @@ DeduceTemplateArgumentsByTypeMatch(Sema
         Comparison.Qualifiers = ParamMoreQualified;
       else if (ArgQuals.isStrictSupersetOf(ParamQuals))
         Comparison.Qualifiers = ArgMoreQualified;
+      else if (ArgQuals.getObjCLifetime() != ParamQuals.getObjCLifetime() &&
+               ArgQuals.withoutObjCLifetime()
+                 == ParamQuals.withoutObjCLifetime()) {
+        // Prefer binding to non-__unsafe_autoretained parameters.
+        if (ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
+            ParamQuals.getObjCLifetime())
+          Comparison.Qualifiers = ParamMoreQualified;
+        else if (ParamQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
+                 ArgQuals.getObjCLifetime())
+          Comparison.Qualifiers = ArgMoreQualified;
+      }
       RefParamComparisons->push_back(Comparison);
     }
 

Modified: cfe/trunk/test/SemaObjCXX/arc-templates.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjCXX/arc-templates.mm?rev=198343&r1=198342&r2=198343&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjCXX/arc-templates.mm (original)
+++ cfe/trunk/test/SemaObjCXX/arc-templates.mm Thu Jan  2 13:42:02 2014
@@ -302,3 +302,19 @@ namespace rdar14467941 {
     float &fr2 = takePtr<A>(a);
   }
 }
+
+namespace rdar15713945 {
+  template <class T> int &f(__strong T &);
+  template <class T> float &f(__weak T &);
+  template <class T> double &f(__unsafe_unretained T &);
+  template <class T> char &f(T &);
+
+  void foo() {
+    __strong NSString * const strong = 0;
+    int &ir = (f)(strong);
+    __weak NSString * const weak = 0;
+    float &fr = (f)(weak);
+    __unsafe_unretained NSString * const unsafe = 0;
+    double &dr = (f)(unsafe);
+  }
+}