-Wreceiver-is-weak: rephrase warning text and add a suggestion Note.

New output:
  warning: weak property may be unpredictably set to nil
  note: property declared here
  note: assign the value to a strong variable to keep the object alive
        during use

<rdar://problem/12277204>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164857 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index c0afb10ef9148afed8617d49a5667d855a1ce18e..57c6907f62d57eee481441929c870a7e35997ae5 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -707,8 +707,10 @@ def err_gc_weak_property_strong_type : Error<
   "weak attribute declared on a __strong type property in GC mode">;
 def warn_receiver_is_weak : Warning <
   "weak %select{receiver|property|implicit property}0 may be "
-  "unpredictably null in ARC mode">,
+  "unpredictably set to nil">,
   InGroup<DiagGroup<"receiver-is-weak">>, DefaultIgnore;
+def note_arc_assign_to_strong : Note<
+  "assign the value to a strong variable to keep the object alive during use">;
 def warn_arc_repeated_use_of_weak : Warning <
   "weak %select{variable|property|implicit property|instance variable}0 %1 is "
   "accessed multiple times in this %select{function|method|block|lambda}2 "

diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index 58e28a94044b79733a7873d38dfc463dcd2af156..f3ae25ed4829f245f0440b89099c0f5767e562dc 100644 (file)
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1341,21 +1341,22 @@ static void DiagnoseARCUseOfWeakReceiver(Sema &S, Expr *Receiver) {
     }
   }
   
-  if (T.getObjCLifetime() == Qualifiers::OCL_Weak) {
-    S.Diag(Loc, diag::warn_receiver_is_weak) 
-      << ((!PDecl && !GDecl) ? 0 : (PDecl ? 1 : 2));
-    if (PDecl)
-      S.Diag(PDecl->getLocation(), diag::note_property_declare);
-    else if (GDecl)
-      S.Diag(GDecl->getLocation(), diag::note_method_declared_at) << GDecl;
-    return;
+  if (T.getObjCLifetime() != Qualifiers::OCL_Weak) {
+    if (!PDecl)
+      return;
+    if (!(PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak))
+      return;
   }
-  
-  if (PDecl && 
-      (PDecl->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)) {
-    S.Diag(Loc, diag::warn_receiver_is_weak) << 1;
+
+  S.Diag(Loc, diag::warn_receiver_is_weak)
+    << ((!PDecl && !GDecl) ? 0 : (PDecl ? 1 : 2));
+
+  if (PDecl)
     S.Diag(PDecl->getLocation(), diag::note_property_declare);
-  }
+  else if (GDecl)
+    S.Diag(GDecl->getLocation(), diag::note_method_declared_at) << GDecl;
+
+  S.Diag(Loc, diag::note_arc_assign_to_strong);
 }
 
 /// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an

diff --git a/test/SemaObjC/weak-receiver-warn.m b/test/SemaObjC/weak-receiver-warn.m
index 547f0087bc404c61f379eee66fce620e6e883f06..2a109dde5ee87fba7ecea63495b034e298eb7fe3 100644 (file)
--- a/test/SemaObjC/weak-receiver-warn.m
+++ b/test/SemaObjC/weak-receiver-warn.m
@@ -9,13 +9,13 @@
 
 void test0(Test0 *x) {
   __weak Test0 *weakx = x;
-  [x addBlock: ^{ [weakx actNow]; }]; // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
-  [x setBlock: ^{ [weakx actNow]; }]; // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
-  x.block = ^{ [weakx actNow]; }; // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
+  [x addBlock: ^{ [weakx actNow]; }]; // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
+  [x setBlock: ^{ [weakx actNow]; }]; // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
+  x.block = ^{ [weakx actNow]; }; // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 
-  [weakx addBlock: ^{ [x actNow]; }]; // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
-  [weakx setBlock: ^{ [x actNow]; }]; // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
-  weakx.block = ^{ [x actNow]; };     // expected-warning {{weak receiver may be unpredictably null in ARC mode}}
+  [weakx addBlock: ^{ [x actNow]; }]; // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
+  [weakx setBlock: ^{ [x actNow]; }]; // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
+  weakx.block = ^{ [x actNow]; };     // expected-warning {{weak receiver may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 }
 
 @interface Test
@@ -36,12 +36,12 @@ void test0(Test0 *x) {
     if (self.weak_atomic_prop) {
       self.weak_atomic_prop = 0;
     }
-    [self.weak_prop Meth]; // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    [self.weak_prop Meth]; // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
     id pi = self.P;
 
-    [self.weak_atomic_prop Meth];  // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    [self.weak_atomic_prop Meth];  // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 
-    [self.P Meth];                // expected-warning {{weak implicit property may be unpredictably null in ARC mode}}
+    [self.P Meth];                // expected-warning {{weak implicit property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 }
 
 - (__weak id) P { return 0; }
@@ -60,9 +60,9 @@ void test0(Test0 *x) {
 
 - (void)doSomething
 {
-    [[self parent] doSomething]; // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    [[self parent] doSomething]; // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 
-    (void)self.parent.doSomething; // expected-warning {{weak property may be unpredictably null in ARC mode}}
+    (void)self.parent.doSomething; // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 }
 
 @end
@@ -74,7 +74,7 @@ void test0(Test0 *x) {
 @end
 
 void testProtocol(id <MyProtocol> input) {
-  [[input object] Meth]; // expected-warning {{weak property may be unpredictably null in ARC mode}}
-  [input.object Meth]; // expected-warning {{weak property may be unpredictably null in ARC mode}}
+  [[input object] Meth]; // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
+  [input.object Meth]; // expected-warning {{weak property may be unpredictably set to nil}} expected-note {{assign the value to a strong variable to keep the object alive during use}}
 }