With -Wselector, don't warn about unimplemented optional method

used in @selector expression because, well, their implementation 
is optional. // rdar://9545564

llvm-svn: 135057

clang/lib/Sema/SemaExprObjC.cpp

@@ -178,11 +178,14 @@ ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
                                           SourceRange(LParenLoc, RParenLoc));
   if (!Method)
     Diag(SelLoc, diag::warn_undeclared_selector) << Sel;
-
-  llvm::DenseMap<Selector, SourceLocation>::iterator Pos
-    = ReferencedSelectors.find(Sel);
-  if (Pos == ReferencedSelectors.end())
-    ReferencedSelectors.insert(std::make_pair(Sel, SelLoc));
+  
+  if (!Method ||
+      Method->getImplementationControl() != ObjCMethodDecl::Optional) {
+    llvm::DenseMap<Selector, SourceLocation>::iterator Pos
+      = ReferencedSelectors.find(Sel);
+    if (Pos == ReferencedSelectors.end())
+      ReferencedSelectors.insert(std::make_pair(Sel, SelLoc));
+  }
 
   // In ARC, forbid the user from using @selector for 
   // retain/release/autorelease/dealloc/retainCount.

clang/test/SemaObjC/selector-3.m

@@ -27,3 +27,28 @@ SEL func()
 {
     return  @selector(length);  // expected-warning {{unimplemented selector 'length'}}
 }
+
+// rdar://9545564
+@class MSPauseManager;
+
+@protocol MSPauseManagerDelegate 
+@optional
+- (void)pauseManagerDidPause:(MSPauseManager *)manager;
+- (int)respondsToSelector:(SEL)aSelector;
+@end
+
+@interface MSPauseManager
+{
+  id<MSPauseManagerDelegate> _delegate;
+}
+@end
+
+
+@implementation MSPauseManager
+- (id) Meth {
+  if ([_delegate respondsToSelector:@selector(pauseManagerDidPause:)])
+    return 0;
+  return 0;
+}
+@end
+