Objective-C arc: don't count use of __weak

variables when they are used in such unevaluated 
contexts as __typeof, etc. // rdar://13942025

llvm-svn: 182423

clang/include/clang/Sema/Sema.h

@@ -957,7 +957,13 @@ public:
   sema::FunctionScopeInfo *getCurFunction() const {
     return FunctionScopes.back();
   }
-
+  
+  template <typename ExprT>
+  void recordUseOfEvaluatedWeak(const ExprT *E, bool IsRead=true) {
+    if (!isUnevaluatedContext())
+      getCurFunction()->recordUseOfWeak(E, IsRead);
+  }
+  
   void PushCompoundScope();
   void PopCompoundScope();
 

clang/lib/Sema/SemaExpr.cpp

@@ -1550,7 +1550,7 @@ Sema::BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
       Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
                                E->getLocStart());
     if (Level != DiagnosticsEngine::Ignored)
-      getCurFunction()->recordUseOfWeak(E);
+      recordUseOfEvaluatedWeak(E);
   }
 
   // Just in case we're building an illegal pointer-to-member.
@@ -2152,7 +2152,7 @@ Sema::LookupInObjCMethod(LookupResult &Lookup, Scope *S,
           DiagnosticsEngine::Level Level =
             Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc);
           if (Level != DiagnosticsEngine::Ignored)
-            getCurFunction()->recordUseOfWeak(Result);
+            recordUseOfEvaluatedWeak(Result);
         }
         if (CurContext->isClosure())
           Diag(Loc, diag::warn_implicitly_retains_self)

clang/lib/Sema/SemaExprMember.cpp

@@ -1311,7 +1311,7 @@ Sema::LookupMemberExpr(LookupResult &R, ExprResult &BaseExpr,
           Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
                                    MemberLoc);
         if (Level != DiagnosticsEngine::Ignored)
-          getCurFunction()->recordUseOfWeak(Result);
+          recordUseOfEvaluatedWeak(Result);
       }
     }
 

clang/lib/Sema/SemaPseudoObject.cpp

@@ -882,8 +882,8 @@ ExprResult ObjCPropertyOpBuilder::complete(Expr *SyntacticForm) {
       S.Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
                                  SyntacticForm->getLocStart());
     if (Level != DiagnosticsEngine::Ignored)
-      S.getCurFunction()->recordUseOfWeak(SyntacticRefExpr,
+      S.recordUseOfEvaluatedWeak(SyntacticRefExpr,
-                                         SyntacticRefExpr->isMessagingGetter());
+                                 SyntacticRefExpr->isMessagingGetter());
   }
 
   return PseudoOpBuilder::complete(SyntacticForm);

clang/test/SemaObjC/arc-repeated-weak.mm

@@ -410,3 +410,18 @@ void doubleLevelAccessIvar(Test *a, Test *b) {
   use(a.strongProp.weakProp); // no-warning
 }
 
+// rdar://13942025
+@interface X
+@end
+
+@implementation X
+- (int) warningAboutWeakVariableInsideTypeof {
+    __typeof__(self) __weak weakSelf = self;
+    ^(){
+        __typeof__(weakSelf) blockSelf = weakSelf;
+        use(blockSelf);
+    }();
+    return sizeof(weakSelf);
+}
+@end
+