Objective-C. Reduce false positive warnings with -Wselector by issuing warning

only when named selector is declared in TU and it is not declared in a system
header. rdar://16600230


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208443 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Fariborz Jahanian

lib/Sema/SemaExprObjC.cpp

@@ -1049,8 +1049,9 @@ ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
   } else
     DiagnoseMismatchedSelectors(*this, AtLoc, Method);
 
-  if (!Method ||
-      Method->getImplementationControl() != ObjCMethodDecl::Optional) {
+  if (Method &&
+      Method->getImplementationControl() != ObjCMethodDecl::Optional &&
+      !getSourceManager().isInSystemHeader(Method->getLocation())) {
     llvm::DenseMap<Selector, SourceLocation>::iterator Pos
       = ReferencedSelectors.find(Sel);
     if (Pos == ReferencedSelectors.end())

test/PCH/Inputs/chain-selectors2.h

@@ -1,6 +1,8 @@
 @interface Y
   -(void)f;
   -(void)f2;
+  -(void)x;
+  -(void)y;
   -(void)e;
 @end
 

test/SemaObjC/selector-3.m

@@ -14,7 +14,7 @@ - (void) bar
 - (void) foo
 {
   SEL a,b,c;
-  a = @selector(b1ar);  // expected-warning {{no method with selector 'b1ar' is implemented in this translation unit}}
+  a = @selector(b1ar);
   b = @selector(bar);
 }
 @end
@@ -69,7 +69,7 @@ - (void) Meth;
 
 @implementation INTF
 - (void) Meth {
-  if( [cnx respondsToSelector:MySelector(@selector( _setQueue: ))] ) // expected-warning {{no method with selector '_setQueue:' is implemented in this translation unit}}
+  if( [cnx respondsToSelector:MySelector(@selector( _setQueue: ))] )
   {
   }
 

test/SemaObjC/selector-4.m

@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -Wselector -x objective-c %s -include %s -verify
+// expected-no-diagnostics
+// rdar://16600230
+
+#ifndef INCLUDED
+#define INCLUDED
+
+#pragma clang system_header
+
+@interface NSObject @end
+@interface NSString @end
+
+@interface NSString (NSStringExtensionMethods)
+- (void)compare:(NSString *)string;
+@end
+
+@interface MyObject : NSObject
+@end
+
+#else
+int main() {
+    (void)@selector(compare:);
+}
+
+@implementation MyObject
+
+@end
+#endif