Objective-C. When we use @selector(save:), etc. there may be more

than one method with mismatched type of same selector name. 
clang issues a warning to point this out since it may cause 
undefined behavior. There are cases though that some APIs 
don't care about user methods and such warnings are perceived as 
noise. This patch allows users to add paren delimiters around
selector name to turn off such warnings. So, @selector((save:)) will
turn off the warning. It also provides 'fixit' so user knows 
what to do. // rdar://16458579

llvm-svn: 211611

1 files changed, 17 insertions, 9 deletions

diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 9fbf656b55a..299dd5d379e 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -976,6 +976,8 @@ ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
 
 static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
                                                SourceLocation AtLoc,
+                                               SourceLocation LParenLoc,
+                                               SourceLocation RParenLoc,
                                                ObjCMethodDecl *Method,
                                                ObjCMethodList &MethList) {
   ObjCMethodList *M = &MethList;
@@ -991,7 +993,8 @@ static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
       if (!Warned) {
         Warned = true;
         S.Diag(AtLoc, diag::warning_multiple_selectors)
-          << Method->getSelector();
+          << Method->getSelector() << FixItHint::CreateInsertion(LParenLoc, "(")
+          << FixItHint::CreateInsertion(RParenLoc, ")");
         S.Diag(Method->getLocation(), diag::note_method_declared_at)
           << Method->getDeclName();
       }
@@ -1003,23 +1006,26 @@ static bool HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
 }
 
 static void DiagnoseMismatchedSelectors(Sema &S, SourceLocation AtLoc,
-                                        ObjCMethodDecl *Method) {
-  if (S.Diags.isIgnored(diag::warning_multiple_selectors, SourceLocation()))
+                                        ObjCMethodDecl *Method,
+                                        SourceLocation LParenLoc,
+                                        SourceLocation RParenLoc,
+                                        bool WarnMultipleSelectors) {
+  if (!WarnMultipleSelectors ||
+      S.Diags.isIgnored(diag::warning_multiple_selectors, SourceLocation()))
     return;
   bool Warned = false;
   for (Sema::GlobalMethodPool::iterator b = S.MethodPool.begin(),
        e = S.MethodPool.end(); b != e; b++) {
     // first, instance methods
     ObjCMethodList &InstMethList = b->second.first;
-    if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc,
+    if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
                                                       Method, InstMethList))
       Warned = true;
         
     // second, class methods
     ObjCMethodList &ClsMethList = b->second.second;
-    if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc,
-                                                      Method, ClsMethList) ||
-        Warned)
+    if (HelperToDiagnoseMismatchedMethodsInGlobalPool(S, AtLoc, LParenLoc, RParenLoc,
+                                                      Method, ClsMethList) || Warned)
       return;
   }
 }
@@ -1028,7 +1034,8 @@ ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
                                              SourceLocation AtLoc,
                                              SourceLocation SelLoc,
                                              SourceLocation LParenLoc,
-                                             SourceLocation RParenLoc) {
+                                             SourceLocation RParenLoc,
+                                             bool WarnMultipleSelectors) {
   ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(Sel,
                              SourceRange(LParenLoc, RParenLoc), false, false);
   if (!Method)
@@ -1046,7 +1053,8 @@ ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
     } else
         Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
   } else
-    DiagnoseMismatchedSelectors(*this, AtLoc, Method);
+    DiagnoseMismatchedSelectors(*this, AtLoc, Method, LParenLoc, RParenLoc,
+                                WarnMultipleSelectors);
   
   if (Method &&
       Method->getImplementationControl() != ObjCMethodDecl::Optional &&